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Tytuł:
2D Cadastral Coordinate Transformation using extreme learning machine technique
Autorzy:
Ziggah, Y. Y.
Issaka, Y.
Laari, P. B.
Hui, Z.
Powiązania:
https://bibliotekanauki.pl/articles/145372.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transformacja współrzędnych
sieci neuronowe
dane geodezyjne
sieć radialna
coordinate transformation
extreme learning machine
backpropagation neural network
radial basis function neural network
geodetic datum
Opis:
Land surveyors, photogrammetrists, remote sensing engineers and professionals in the Earth sciences are often faced with the task of transferring coordinates from one geodetic datum into another to serve their desired purpose. The essence is to create compatibility between data related to different geodetic reference frames for geospatial applications. Strictly speaking, conventional techniques of conformal, affine and projective transformation models are mostly used to accomplish such task. With developing countries like Ghana where there is no immediate plans to establish geocentric datum and still rely on the astro-geodetic datums as it national mapping reference surface, there is the urgent need to explore the suitability of other transformation methods. In this study, an effort has been made to explore the proficiency of the Extreme Learning Machine (ELM) as a novel alternative coordinate transformation method. The proposed ELM approach was applied to data found in the Ghana geodetic reference network. The ELM transformation result has been analysed and compared with benchmark methods of backpropagation neural network (BPNN), radial basis function neural network (RBFNN), two-dimensional (2D) affine and 2D conformal. The overall study results indicate that the ELM can produce comparable transformation results to the widely used BPNN and RBFNN, but better than the 2D affine and 2D conformal. The results produced by ELM has demonstrated it as a promising tool for coordinate transformation in Ghana.
Źródło:
Geodesy and Cartography; 2018, 67, 2; 321-343
2080-6736
2300-2581
Pojawia się w:
Geodesy and Cartography
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
35 mm ammunition’s trajectory model identification based on firing tables
Autorzy:
Baranowski, L.
Gadomski, B.
Majewski, P.
Szymonik, J.
Powiązania:
https://bibliotekanauki.pl/articles/200598.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
identification
exterior ballistics
equations of projectile motion
curve fitting
drag coefficient
identyfikacja
ruch pocisku
współczynnik oporu
Opis:
The article presents a procedure designed for identification of projectile’s trajectory model through aerodynamic coefficients estimation. The identification process is based on firing tables artificially prepared (firing tables prepared using mathematical flight model for the projectile instead of trajectories recorded on field tests) with the use of modified point–mass and rigid body trajectory models. All the necessary data, including physical parameters of the projectile and its aerodynamic characteristics are provided. The detailed results of estimation of chosen aerodynamic coefficients are presented in both visual and tabular form. The main purpose of this paper is to establish the minimum number of trajectories (as characterized in firing tables), and the permissible error of initial parameters being passed to the mathematical model that would allow the correct identification of projectile’s trajectory model.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 5; 635-643
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D ABAQUS simulation of bent softwood elements
Symulacja 3D zginanych elementów z miękkiego drewna w programie ABAQUS
Autorzy:
Kawecki, B.
Podgórski, J.
Powiązania:
https://bibliotekanauki.pl/articles/230344.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metoda elementów skończonych
modelowanie
drewno miękkie
pękanie
zniszczenie
finite element method
modelling
softwood
fracture
destruction
Opis:
Artykuł przedstawia sposób modelowania elementów zginanych wykonanych z miękkiego drewna. Taki rodzaj drewna jest najczęściej wykorzystywany w konstrukcjach budowlanych. Autorzy wykonali zwięzły przegląd sposobów modelowania drewna na podstawie literatury. Znalazły się w nim trzy podstawowe podejścia: liniowo-sprężysta mechanika pękania (LEFM), mechanika zniszczenia ośrodków ciągłych (CDM) i funkcja Hilla (HF). W pracy zaproponowano rozwiązanie oparte na funkcji Hilla, która dostępna jest w programie ABAQUS. Zróżnicowane zachowanie materiału przy ściskaniu i rozciąganiu osiągnięto poprzez teoretyczny podział modelu na strefę ściskaną i rozciąganą. W obu strefach przyjęto różną wytrzymałość wzdłuż włókien w zależności od panującego stanu naprężenia. Na podstawie badań laboratoryjnych wprowadzono ogólne zależności pomiędzy parametrami sprężystymi i wytrzymałościowymi. Dzięki temu do zastosowania modelu wystarczające jest obliczenie modułu sprężystości wzdłuż włókien (EL) i wytrzymałości na rozciąganie przy zginaniu (MOR). Oba parametry można wyznaczyć bezpośrednio w badaniu trójpunktowego zginania. Prawidłowość modelu MES została potwierdzona badaniami laboratoryjnymi oraz metodą cyfrowej korelacji obrazu (DIC). Model umożliwia przewidywanie zachowania elementów z drewna przy zginaniu w stanie 3D. Uwzględnia zarówno plastyczne płynięcie w środkowej fazie obciążenia, spowodowane przekroczeniem wytrzymałości na ściskanie, jak i przewidywanie siły maksymalnej w wyniku rozciągania. Rozwiązanie jest bardzo praktyczne ze względu na brak problemów ze zbieżnością obliczeń. Dodatkowo liczba wymaganych parametrów jest znacznie mniejsza niż w przypadku innych metod odnalezionych w literaturze.
The article presents research on modelling fracture in softwood bent elements. This kind of timber is the one most exploited for construction. Authors present a brief review on the subject with emphasis on three basic attempts: Linear Elastic Fracture Mechanics (LEFM), Continuum Damage Mechanics (CDM) and Hill’s Function (HF). Proposed 3D solution bases on Hill’s Function applied in the ABAQUS FEM code. The new idea includes isolating theoretical compression and tension zones in a model. Then, it is possible to distinguish between compressive and tensile strength and predict a real behaviour of bent elements. Introducing general dependencies between material properties leads to the need of determining only longitudinal elastic modulus (EL) and modulus of rupture (MOR). It is practical because these parameters are the main reported in a scientific and technical literature. Authors describe all of the assumptions in details. The experimental tests and Digital Image Correlation method (DIC) validate the FEM model.
Źródło:
Archives of Civil Engineering; 2020, 66, 3; 323-337
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D Acoustic Field Intensity Probe Design and Measurements
Autorzy:
Kotus, J.
Czyżewski, A.
Kostek, B.
Powiązania:
https://bibliotekanauki.pl/articles/176807.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound intensity
acoustic vector sensor
calibration
measurements
Opis:
The aim of this paper is two-fold. First, some basic notions on acoustic field intensity and its measurement are shortly recalled. Then, the equipment and the measurement procedure used in the sound intensity in the performed research study are described. The second goal is to present details of the design of the engineered 3D intensity probe, as well as the algorithms developed and applied for that purpose. Results of the intensity probe measurements along with the calibration procedure are then contained and discussed. Comparison between the engineered and the reference commercial probe confirms that the designed construction is applicable to the sound field intensity measurements with a sufficient effectiveness.
Źródło:
Archives of Acoustics; 2016, 41, 4; 701-711
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D field analysis in 3-phase amorphous modular transformer under increased frequency operation
Autorzy:
Tomczuk, B.
Koteras, D.
Powiązania:
https://bibliotekanauki.pl/articles/141706.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
3D field analysis
temperature calculation
eddy current losses
measurement tests
Opis:
The calculations results of the temperature distribution in a 3-phase transformer with modular amorphous core are presented. They were performed for two frequency values which were higher than the power system one. For the 3D field analyses the Finite Element Method (FEM) was used. The calculated temperature at the points of the core surface has been verified using an infrared camera.
Źródło:
Archives of Electrical Engineering; 2015, 64, 1; 119-127
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D Model Studies on the Effect of Bed and Powder Type Upon Radial Static Pressure and Powder Distribution in Metallurgical Shaft Furnaces
Autorzy:
Panic, B.
Powiązania:
https://bibliotekanauki.pl/articles/351694.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
blast furnace
system descending packed bed–gas-powder
pressure
holdup powder
Opis:
The flow of gases in metallurgical shaft furnaces has a decisive influence on the course and process efficiency. Radial changes in porosity of the bed cause uneven flow of gas along the radius of the reactor, which sometimes is deliberate and intentional. However, holdup of solid particles in descending packed beds of metallurgical shaft furnaces can lead to unintentional changes in porosity of the bed along the radial reactor. Unintentional changes in porosity often disrupt the flow of gas causing poor performance of the furnace. Such disruptions of flow may occur in the blast furnace due to high level of powder content in gas caused by large amount of coal dust/powder insufflated as fuel substitute. The paper describes the model test results of radial distribution of static pressure and powder hold up within metallurgical reactor. The measurements were carried out with the use of 3D physical model of two-phase flow gas-powder in the moving (descending) packed bed. Sinter or blast furnace pellets were used as packed bed while carbon powder or iron powder were used as the powder. Wide diversity within both static pressure distribution and powder distribution along the radius of the reactor were observed once the change in the type of powder occurred.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1449-1452
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D Model Study of Radial Distribution of Powder Holdup in the Descending Packed Bed of Metallurgical Shaft Furnaces
Autorzy:
Panic, B.
Powiązania:
https://bibliotekanauki.pl/articles/353435.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
blast furnace
system descending packed bed–gas-powder
radial distribution of powder
Opis:
The principle of work of many metallurgical shaft furnaces is based on the flow of reaction gas through the descending packed bed composed of metallurgical materials. Hot gases flow up the shaft furnace through the column of materials, give their heat to the descending charge materials. At the same time due to their reducing nature they interact chemically, causing the reduction of oxides inside the charge. In real conditions, during the course of the process, the powder is generated, the source of which is the batch materials or it is introduced into the as part of the process procedure. The powder in the form of thin slurry is carried by the stream of flowing gas. Such multiphase flow might considerably affect the permeability of the charge due to the local holdup of powder. The holdup of solid phase in packed beds of metallurgical shaft furnaces leads to radial changes in bed porosity. Radial changes in bed porosity uneven gas flow along the radius of the reactor and negatively affect the course and efficiency of the process. The article describes the model studies on radial distribution of carbon powder holdup in the packed bed composed of metallurgical materials. The powder was divided into fractions – "static" and "dynamic". Large diversity of carbon powder distribution was observed in the function of the radius of reactor in relation to the bed type, apparent velocity of gas carrying powder and the level of bed height.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 999-1002
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A 34-year retrospective study of equine viral abortion in Poland
Autorzy:
Bazanow, B.A.
Fracka, A.B.
Jackulak, N.A.
Staroniewicz, Z.M.
Ploch, S.M.
Powiązania:
https://bibliotekanauki.pl/articles/31818.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The purpose of the present review was a comparison of the abortions caused by EAV and EHV-1 viruses over the 34 years. A total of 452 tissues samples from aborted fetuses (347) or foals (105) stillborn or newborn that died within 72 hours were investigated. The material for the examinations came from different farms located throughout Poland. The tissue homogenates were examined by using virus isolation test in RK-13 and Vero cell lines and the cytopathic agent was confirmed as EHV-1 by the direct fluorescent antibody test or as EAV by the indirect fluorescent antibody test. The study indicated that EAV was isolated (104 cases, 23%) almost as equally often as EHV-1 (116 cases, 25.6%). Both, equid herpesvirus-associated abortion and the abortion induced by EAV were characterized by cyclicity. The percentage of EAV and EHV-1 isolation alternately reduced and increased, but the increase of isolation of one virus was accompanied by the decrease of the other. The domination of one virus over the other occurred in cycles of a few years.
Źródło:
Polish Journal of Veterinary Sciences; 2014, 17, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Bayesian virtual metrology for quality inspection of mobile repeater systems
Autorzy:
Kim, S. D.
Kim, J. S.
Mun, B. M.
Bae, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/406820.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Bayesian approach
regression
conjugate priors
ICS repeater
Markov chain Monte Carlo
Opis:
The technology of wideband code division multiple access (WCDMA) has been applied to band selective interference cancellation system (ICS) repeaters. To inspect the telecommunication quality of the systems, quality engineers must check the shape of the signals at the corresponding frequency band of the repeaters. However, measuring the signal quality is a repetitive manual task which requires much inspection time and high costs. In the case of small-sized samples, such as the example of an ICS repeater system, Bayesian approaches have been employed to improve the estimation accuracy by incorporating prior information on the parameters of the model in consideration. This research proposes a virtual method of quality inspection for products using a correlation structure of measurement data, mainly in a Bayesian regression framework. The Bayesian regression model derives prior information from historical measurement data to predict measurements of other frequency bandwidths by exploiting the correlation structure of each measurement data. Empirical results show the potential for reducing inspection costs and time by predicting the values of adjoining frequency bandwidths through measured data of a frequency bandwidth in the course of quality inspections of ICS repeater systems.
Źródło:
Management and Production Engineering Review; 2016, 7, 4; 48-53
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A clinical, cytogenetic and molecular study in Prader-Willi patients
Autorzy:
Krajewska-Walasek, M
Popowska, E
Gutkowska, A
Bielinska, B
Chrzanowska, K
Rump, Z
Mospinek-Krasnopolska, M
Rysiewski, H
Powiązania:
https://bibliotekanauki.pl/articles/2046801.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
deletion
patient
cytogenetic deletion
diagnosis
chromosome 15
Prader-Willi syndrome
Opis:
Twenty-three patients with a putative diagnosis of Prader-Willi syndrome (PWS) were reassessed clinically and then examined by cytogenetic and molecular techniques. Nineteen patients fulfilled the diagnostic criteria for PWS and the remaining four were judged to have atypical PWS. Definite molecular defects were detected in all clinically typical PWS patients but one. A deletion of part of chromosome 15q could be identified molecularly in 14 patients (74%) and maternal disomy for chromosome 15 in four (21%). In all, except one, PWS patients with molecularly detected deletions, the deletion was also identified by cytogenetic studies. Cytogenetic deletions were suspected in two of the atypical PWS patients. However, based on the results of scoring the diagnostic criteria for PWS and on the PW71B methylation test, we were able to rule out PWS in all of our atypical patients. Our study confirms observations that both clinical and cytogenetic investigations can provide misdiagnoses of PWS in some patients, and the first, simple and fast investigation, which can confirm the PWS in most, if not all PWS patients, is molecular analysis by the methylation test.
Źródło:
Journal of Applied Genetics; 1997, 38, 2; 205-216
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Study on Ex-Situ & In-Situ Formed Metal Matrix Composites
Autorzy:
Gobalakrishnan, B.
Rajaravi, C.
Udhayakumar, Gobikrishnan
Lakshminarayanan, P. R.
Powiązania:
https://bibliotekanauki.pl/articles/2203734.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MMCs
Al-SiC
Al-TiB2
extrusion
heat treatment
mechanical properties
microstructure
Opis:
An attempt has been made to synthesize the aluminium based ex-situ (Al-SiC) and in-situ (Al-TiB2) formed metal matrix composites with varying weight percentage of reinforcement contents such as 4wt.%, 6wt.% and 8wt.%. Synthesized composites were subjected to a cold extrusion process followed by heat treatment according to the ASTM B 918-01 standards. The mechanical properties of in-situ composites were evaluated as per the ASTM guidelines and compared with ex-situ formed composites and base metal properties. Superior properties were noticed in the in-situ formed composites and the mechanical properties such as yield strength, Ultimate tensile strength (UTS) and Hardness for both ex-situ and in-situ composites were found to increase with increasing the reinforcement addition. Cold extruded Al-8 wt.% SiC composite properties such as hardness, yield strength and UTS are 87 RB, 152 MPa, 216 MPa respectively. Whereas, for Al-8 wt.% TiB2 composite, the corresponding properties are 94 RB, 192 MPa, 293 MPa. The morphology of the composites is analysed by Optical and Scanning Electron Microscopic (SEM) whereas presence of reinforcement particles such SiC and TiB2 along with intermetallic phases Mg2Si and Al5FeSi are confirmed by EDX, XRD and Element Mapping analyses.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 171--185
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of antioxidant systems between Pisum sativum and Brassica juncea indicates high disproportion in H2O2 level
Autorzy:
Kutrowska, A.
Piechalak, A.
Wojtera-Kwiczor, J.
Malecka, A.
Tomaszewska, B.
Powiązania:
https://bibliotekanauki.pl/articles/80674.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
antioxidant
gene expression
Pisum sativum
Brassica juncea
hydrogen peroxide
trace element
reactive oxygen species
oxidative stress
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of Data Traffic in Standardized Personal Health Monitoring Solutions
Autorzy:
Schuler, A.
Franz, B.
Krauss, O.
Powiązania:
https://bibliotekanauki.pl/articles/227023.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fast healthcare interoperability resources
integrating the healthcare enterprise
continua health alliance
telemonitoring
electronic health record
SOAP
representational state transfer
m-health
e-health
Opis:
The publication of the HL7-FHIR standard offers new possibilities for integrated applications in healthcare. Although trial implementations have only recently started, the application of FHIR in context of a Personal Health Monitoring solution is worth investigating. Most of the existing telemonitoring solutions in healthcare rely on guidelines defined by the Continua Health Alliance (CHA). This paper compares the requirements of CHA and HL7-FHIR with respect to data traffic between client devices and server side applications. Therefore an existing CHA-compliant telemonitoring solution is extended towards supporting HL7-FHIR. Both approaches were simultaneously evaluated in a live system with 68 participants. The results of the evaluation show that the FHIR approach offers the possibility of reducing data traffic in comparison to the CHA solution.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 2; 143-149
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of nature inspired algorithms for the quadratic assignment problem
Autorzy:
Chmiel, W.
Kadłuczka, P.
Kwiecień, J.
Filipowicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/202135.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
permutation problem
quadratic assignment problem
ant algorithm
bees algorithm
problem permutacji
problem przydziału kwadratowego
algorytm Ant Colony
algorytm pszczół
Opis:
This paper presents an application of the ant algorithm and bees algorithm in optimization of QAP problem as an example of NP-hard optimization problem. The experiments with two types of algorithms: the bees algorithm and the ant algorithm were performed for the test instances of the quadratic assignment problem from QAPLIB, designed by Burkard, Karisch and Rendl. On the basis of the experiments results, an influence of particular elements of algorithms, including neighbourhood size and neighbourhood search method, will be determined.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 4; 513-522
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comprehensive in silico prediction of the most deleterious missense variants in the bovine LEP gene
Autorzy:
Al-Shuhaib, M.B.S.
Powiązania:
https://bibliotekanauki.pl/articles/80824.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LEP gene
leptin
biological activity
bovine gene
single nucleotide polymorphism
coding sequence
cattle
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2019, 100, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A concept of propulsion and power supply systems for PRT vehicles
Koncepcja systemów napędowych i zasilania dla pojazdów PRT
Autorzy:
Kamiński, B.
Nikoniuk, M.
Drązikowski, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/224077.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PRT vehicles
hybrid power
propulsion systems
pojazd PRT
zasilanie hybrydowe
systemy napędowe
Opis:
An innovative propulsion and power supply topology for Personal Rapid Transit is presented. The concept is based on application of linear induction motor for propulsion and hybrid power supply using Contactless Energy Transfer supported by a supercapacitor energy storage. Proposed solution is based on the application of linear induction motor as a propulsion and inductive contactless energy transfer.
Zaprezentowano topologię innowacyjnego napędu i zasilania Personal Rapid Transit. Koncepcja opiera się na zastosowaniu liniowego silnika indukcyjnego do napędu i hybrydowego zasilania z użyciem bezstykowego przenoszenia energii wspieranego przez kondensator magazynowania energii. Zaproponowane rozwiązanie polega na zastosowaniu liniowego silnika indukcyjnego, jako napędu i indukcyjnym bezstykowym przekazie energii.
Źródło:
Archives of Transport; 2013, 27-28, 3-4; 81-93
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A control topology for frequency regulation capability in a grid integrated PV system
Autorzy:
Kumar, Ritesh
Sahu, Balakrushna
Shiva, Chandan Kumar
Rajender, B.
Powiązania:
https://bibliotekanauki.pl/articles/140902.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
frequency controller
maximum power point tracking (MPPT)
photovoltaic (PV)
power system
pseudo maximum power point tracking (PMPPT)
Opis:
Photovoltaic (PV) cells are very costly because of the silicon element which is not cheaply available. Usually, PV cells are preferred to be used at maximum efficiency. Therefore, PV plants are emphasized to extract maximum power from PV cells. When inertia free PV plants are integrated into the grid in large numbers, the problem of maintaining system stability subjected to load perturbation is quite difficult. In response to this, a control topology is being an approach to make available the PV cells in maintaining system stability by utilizing the system frequency deviation as feedback to the controller. To implement this, the PVs are operated at Maximum Power Point Tracking (MPPT). This allows the PV to operate at Pseudo Maximum Power Point tracking (PMPPT) which makes it possible to run the PV with reserve power capacity without employing a battery for storage. The control strategy has been implemented over a two-stage power conversion model of the PV system. The simulation results showed that the proposed control PMPPT topology is effective in frequency regulation capability as compared to the MPPT technique.
Źródło:
Archives of Electrical Engineering; 2020, 69, 2; 389-401
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A correlation by chemometric methods of Solanum tuberosum epicuticular wax components and plant infestation with Leptinotarsa decemlineata [Say]
Autorzy:
Szafranek, B.
Synak, E.
Nawrot, J.
Malinski, E.
Szafranek, J.
Powiązania:
https://bibliotekanauki.pl/articles/65492.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
epicuticular wax
chemometric method
pest
Solanum tuberosum
Leptinotarsa decemlineata
Colorado potato beetle
plant infestation
Źródło:
Journal of Plant Protection Research; 2002, 42, 3
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A coupled field-circuit model of a 5-phase permanent magnet tubular linear motor
Autorzy:
Tomczuk, B.
Waindok, A.
Powiązania:
https://bibliotekanauki.pl/articles/141318.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silnik synchroniczny liniowy
magnes trwały
PMLSM
metoda polowo-obwodowa
symulacja
parametry sterowania
permanent magnet linear synchronous motors
field-circuit method
simulation of the transients
control parameters
Opis:
A method for modeling of the dynamics characteristics for a 5-phase permanent magnet tubular linear motor (PMTLM) is presented. Its electromagnetic nonlinear field analysis with finite element method (FEM) has been coupled with the circuit model. The calculation model includes the equations for electrical circuits and mechanical quantities as well. They have been obtained using Lagrange's method. The calculated and measured waves of the mover position have been compared for several values of the excitation current. This comparison yields a good agreement. Presented calculation model is very useful in designing and optimization of the PMTLM and in the calculation of the parameters for the control algorithms intended for such a type of actuators.
Źródło:
Archives of Electrical Engineering; 2011, 60, 1; 5-14
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A critical review on soil ionisation modelling for grounding electrodes
Autorzy:
Mokhtari, M.
Abdul-Malek, Z.
Gharehpetian, G.B.
Powiązania:
https://bibliotekanauki.pl/articles/950672.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grounding electrodes
grounding electrode resistance
soil ionisation modelling
Opis:
Grounding electrode resistance non-linearly changes under impulse conditions due to soil ionisation phenomenon. Several models have been proposed to model soil ionisation for grounding electrodes applications. However, to date, there is yet an attempt made to compile all these works into a comprehensive review article. Therefore, this paper is written with the objective of summarizing all related works in this field as a one– stop reference. With reference to the literature, this paper is written to summarize the working principles of the soil ionisation models as well as the accuracy and performance analysis of the models. This paper, particularly highlights the deficiencies of the available models in terms of accuracy and performance. This knowledge will contribute to the development of a new accurate and efficient soil ionisation model.
Źródło:
Archives of Electrical Engineering; 2016, 65, 3; 449-461
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Dedispersion Transform Method for Extracting the Normal Modes of a Shallow Water Acoustic Signal in the Pekeris Waveguide
Autorzy:
Yang, G.- B.
Lü, L.- G.
Gao, D.- Z.
Jiang, Y.
Liu, H.- N.
Powiązania:
https://bibliotekanauki.pl/articles/177234.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
normal mode extraction
dedispersion transform
Pekeris waveguide
source ranging
Opis:
The normal modes cannot be extracted even in the Pekeris waveguide when the source-receiver distance is very close. This paper introduces a normal mode extraction method based on a dedispersion transform (DDT) to solve this problem. The method presented here takes advantage of DDT, which is based on the waveguide invariant such that the dispersion associated with all of the normal modes is removed at the same time. After performing DDT on a signal received in the Pekeris waveguide, the waveform of resulting normal modes is very close to the source signal, each with different position and amplitude. Each normal mode can be extracted by determining its position and amplitude parameters by applying particle swarm optimization (PSO). The waveform of the extracted normal mode is simply the waveform of the source signal; the real waveform of the received normal mode can then be recovered by applying dispersion compensation to the source signal. The method presented needs only one receiver and is verified with experimental data.
Źródło:
Archives of Acoustics; 2015, 40, 1; 11-18
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A discontinuous Galerkin finite element method for dynamic of fully saturated soil
Rozwiązanie zadania dynamiki całkowicie nawodnionego gruntu przy zastosowaniu mes z nieciągłym sformułowaniem Galerkina w czasie
Autorzy:
Wrana, B.
Powiązania:
https://bibliotekanauki.pl/articles/230501.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dynamika gruntu
metoda elementów skończonych
sformułowanie nieciągłe Galerkina
rozchodzenie się fal
grunt całkowicie nawodniony
soil dynamic
finite element method
discontinuous Galerkin method
wave propagation
saturated porous soil
Opis:
The fully coupled, porous solid-fluid dynamic field equations with u - p formulation are used in this paper to simulate pore fluid and solid skeleton responses. The present formulation uses physical damping, which dissipates energy by velocity proportional damping. The proposed damping model takes into account the interaction of pore fluid and solid skeleton. The paper focuses on formulation and implementation of Time Discontinuous Galerkin (TOG) methods for soil dynamics in the case of fully saturated soil. This method uses both the displacements and velocities as basic unknowns and approximates them through piecewise linear functions which are continuous in space and discontinuous in time. This leads to stable and third-order accurate solution algorithms for ordinary differential equations. Numerical results using the time-discontinuous Galerkin FEM are compared with results using a conventional central difference, Houbolt, Wilson Fi, HHT-alfa, and Newmark methods. This comparison reveals that the time-discontinuous Galerkin FEM is more stable and more accurate than these traditional methods.
Artykuł podejmuje zagadnjenie analizy rozchodzenia się fal naprężenjowych w gruncie w ujęciu metody elementów skończonych bazując na sformułowaniu rozwiązania ciągłego w przestrzeni i nieciągłego w dziedzinie czasu Galerkina (space and time-discontinous Galerkin TDG finite element method). W tym sformułowaniu zarówno przemieszczenia jak i prędkości są wielkościamj nieznanymi wzajemnie niezależnymi aproksymowanymi ciągłymi funkcjami kształtu w przestrzeni i nieciągłymi funkcjami kształtu w czasie. Do opisu zachowania się gruntu w pełni nasyconego wodą zastosowano sformułowanie u-p w ujęciu metody elementów skończonych. Grunt traktowany jest, jako ośrodek dwufazowy składający się ze szkieletu i wody w porach. Zastosowane sformułowanie uwzględnia tłumienie ośrodka przez uwzględnienie dyssypacji energii proporcjonalnej do prędkości wody względem szkieletu. W artykule przedstawiono porównanie proponowanej metody rozwiązania numerycznego w dziedzinie czasu do metod obecnie stosowanych, takich jak: metoda różnicy centralnej, metoda Houbolta, Wilsona fi, HHT-alfa oraz najczęściej stosowanej metody Newmarka. Z porównania wynika, że proponowana metoda jest metodą stabilną o małym błędzie numerycznego rozwiązania.
Źródło:
Archives of Civil Engineering; 2011, 57, 1; 119-134
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hybrid (hydro-numerical) circulatory model: investigations of mechanical aortic valves and a numerical valve model
Autorzy:
Kozarski, M.
Suwalski, P.
Zieliński, K.
Górczyńska, K.
Szafron, B.
Pałko, K. J.
Smoczyński, R.
Darowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/202199.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biological and mechanical heart valves
numerical heart valve
hybrid (hydro-numerical) circulatory model
voltage-controlled hydraulic pressure (flow) source
hydraulic input impedance
varying-elastance left ventricle
Opis:
In most cases of diseased heart valves, they can be repaired or replaced with biological or mechanical prostheses. Biological prostheses seem to be safer than mechanical ones and are applied with good clinical outcomes. Their disadvantage, when compared with mechanical valves, is durability. In the development and application of mechanical and biological heart valves, a significant role can be played by a Hybrid (Hydro-Numerical) Circulatory Model. The aim of this paper is to demonstrate the opportunities created by the hybrid model for investigations of mechanical heart valves and their computer models under conditions similar to those of the circulatory system. A diode-resistor numerical valve model and three different design mechanical aortic valves were tested. To perform their investigations, computer applications were developed under RT LabView to be run on a PC. Static and dynamic characteristics of the valves were measured and registered - pressure in the numerical time-varying elastance left ventricle (pLV), in the aorta (pas) and flow (f), proving, among other factors, that 1) time delay of pas with respect to pLV is mainly related to the valve’s opening time, and 2) the valves of substantially different designs tested under identical hydrodynamic conditions reveal nearly the same dynamic performance.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 3; 605-612
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A laboratory and field condition comparison of life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae)
Autorzy:
Hosseini-Tabesh, B.
Sahragard, A.
Karimi-Malati, A.
Powiązania:
https://bibliotekanauki.pl/articles/66204.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Life table studies are essential tools for understanding population dynamics. The life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae) feeding on the host plant, Hibiscus syriacus L. were studied under laboratory (25±1°C and relative humidity of 65±5% and a photoperiod of 16L : 8D h) and field conditions (23–43°C, and relative humidity of 27–95%). The data were analysed using the age-stage, two-sex life table theory. The life table studies were started with 50 and 40 nymphs in laboratory and field conditions, respectively. Under laboratory conditions, A. gossypii reared on H. syriacus had a higher survival rate, fecundity, and longevity than those reared under field conditions. When reared under field conditions, A. gossypii had a longer nymphal developmental time, shorter adult longevity, and lower fecundity than those reared under laboratory conditions. The intrinsic rate of increase (r), net reproductive rate (R0), and the finite rate of increase (λ) under laboratory conditions, were higher than those obtained under field conditions. Nevertheless, there were no significant differences in the mean generation time T (days) between field and laboratory conditions. In the present study, the results clearly showed that life table parameters of A. gossypii were significantly different under field and laboratory conditions. These results could help us to understand the A. gossypii population dynamics under field conditions. The results could also help us make better management decisions for economically important crops.
Źródło:
Journal of Plant Protection Research; 2015, 55, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A lag in the advancement of biotechnology; reliable control of maize stem borers in Africa
Autorzy:
Samuel, A.O.
Tabbassum, B.
Sharif, M.N.
Bhatti, M.U.
Nasir, I.A.
Husnain, T.
Powiązania:
https://bibliotekanauki.pl/articles/65339.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
climate change
food security
integrated pest management
pest management
pest control
maize
stem
borer
RNAi technology
Opis:
The future of food security in Africa is being severely threatened due to an exponential increase in population, which is almost three times the increase of food production. Maize production is constrained by stem borers which cause significant yield losses. Yield losses can be further compounded by higher temperatures due to climate changes, which are expected to increase the population of maize stem borers. While several methods have been employed in stem borer management, there is still significant damage caused by maize stem borers. This necessitates better control methods including the adoption of recent biotechnological advancement in RNA interference (RNAi) technology. This review highlights evidence of an increase in the stem borer population as well as the foreseen decline in maize production worldwide due to the effects of climatic changes. Furthermore, we have drawn attention to improved methods that have been used to control stem borers in maize production as well as a reluctant acceptance of traditional biotechnology in Africa. Finally, we suggest the application of alternative RNA interference techniques to breed maize for efficient pest control in order to achieve food security, improve nutrition and promote sustainable maize production.
Źródło:
Journal of Plant Protection Research; 2018, 58, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A literature review of electronic data interchange as electronic business communication for manufacturing
Autorzy:
Yunitarini, R.
Pratikto, -
Santoso, P. B.
Sugiono, -
Powiązania:
https://bibliotekanauki.pl/articles/952865.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electronic data interchange
communication
manufacture
business
Opis:
In the present dynamic environment, manufacture are required to reduce product development cycle time and enhance product quality. To meet such challenges many business are developing closer relationships with their business partner through application of interorganisational system. Electronic data interchange (EDI) providing a structured form of communication and has become very popular vehicle for electronic communication. Since the EDI concept was popularised in 1990, there is a growing recognition by practitioners and academics. The aim of this study is to perform an analysis of EDI research, give the current discussion regarding the trends and note the suggestions for the future directions of EDI research in the manufacture. In this paper, we provide a wide coverage of excessively citations on EDI from 1990 to 2017 from good references in this area. The papers are classified into EDI implementation strategy, EDI adoption, EDI integration, EDI in supply chain and EDI in small and medium enterprises (SMEs). The study results of this literature review are expected to assist development of EDI research especially the implementation of EDI on production outsourcing as one of supply chain activities.
Źródło:
Management and Production Engineering Review; 2018, 9, 4; 117-128
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Modern Approach to the Asynchronous Sequential Circuit Synthesis
Synteza asynchronicznych układów cyfrowych : nowe horyzonty
Autorzy:
Czekalski, P.
Tokarz, K.
Pochopień, B.
Powiązania:
https://bibliotekanauki.pl/articles/375687.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
logic circuits
automatic control
web service
układy logiczne
automatyczna kontrola
serwis internetowy
Opis:
This paper presents novel approach to the Huffman’s asynchronous sequential circuit two valued Boolean switching system design. The algorithm is implemented as software using distributed, service oriented application model with means of the web service component design. It considers method implementation challenges, both towards Moore and Mealy structures with particular respect to the estimation of the Huffman’s minimization algorithm computational complexity. The paper provides implementation details, theoretical model estimation and experimental results that acknowledge the theoretical approach in practice. This paper also examine the multistep design process implementation and its problems inherent in web service based environment both for development and educational purposes.
Synteza asynchronicznych układów cyfrowych w logice szytej, bazująca na dwuwartościowej algebrze Boole’a, doczekała się licznych modeli i metod implementacji. Najpopularniejsze z nich to metoda Huffmana [2] oraz metoda Tablicy Kolejności Łączeń [3]. Metody te, jakkolwiek powstały w połowie XX wieku, są stosowane również obecnie, zarówno w procesie projektowania przemysłowego jak i w edukacji [10][11][14]. Metoda Huffmana pozwala na syntezę układów o strukturach Moore’a (Fig.1) i Mealy’ego (Fig.2). Proces projektowania z wykorzystaniem metody Huffmana jest wieloetapową metodą o deterministycznym przebiegu. W niniejszym opracowaniu przedstawiono nowatorskie podejście do zagadnienia automatycznego projektowania cyfrowych układów asynchronicznych, bazujące na wytworzeniu oprogramowania o budowie komponentowej oraz z zastosowaniem zunifikowanej komunikacji w sieci WEB z wykorzystaniem protokołu SOAP. Na podstawie teoretycznego modelu opracowano rozwiązanie programowe, składające się z bezstanowego serwisu obliczeniowego oraz aplikacji sieciowej WWW, która służy, jako interfejs użytkownika dla usługi obliczeniowej. W zastosowaniach edukacyjnych przewidziano zwracanie szczegółowych informacji z wszystkich etapów syntezy układów metodą Huffmana, co umożliwia ich wizualizację oraz poruszanie się po nich w przód i w tył, w celu prezentacji zależności i sposobu działania, co stanowi również element zdalnego nauczania - aplikacja WWW jest bowiem widoczna w globalnej sieci Internet (adres znajduje się w Appendix A). Ponieważ metoda Huffmana udostępnia wyniki w postaci zredukowanej i zakodowanej siatki bloku pamięci i bloku kombinacyjnego wyjściowego, serwis obliczeniowy korzysta z uprzednio przygotowanej, zewnętrznej usługi, implementującej funkcjonalność minimalizacji funkcji Boolowskiej metodą Kazakowa. W ramach prowadzonych badań przeanalizowano teoretyczną, pesymistyczną złożoność obliczeniową poszczególnych etapów metody Huffmana, a także łączną, pełną złożoność obliczeniową metody, w szczególności względem liczby sygnałów wejściowych, liczby stanów wewnętrznych oraz liczby sygnałów wyjściowych, otrzymując pełny model złożoności obliczeniowej metody Huffmana. Przeprowadzono szereg eksperymentów, aby potwierdzić oszacowaną teoretycznie złożoność obliczeniową w sposób doświadczalny (Tab. 2-4). Przeprowadzone eksperymenty potwierdziły zgodność z teoretycznie wyznaczonym modelem złożoności obliczeniowej, zarówno dla układów Moore’a jak i Mealy’ego (Tab. 5, Fig. 5 i 6). Na potrzeby sformalizowania zapisu wykresu czasowego opracowano gramatykę zapisu przełączania sygnałów (Appendix B). Stanowi ona format wewnętrzny danych wejściowych dla usługi obliczeniowej implementującej metodę Huffmana.
Źródło:
Theoretical and Applied Informatics; 2014, 26, 1-2; 25-37
1896-5334
Pojawia się w:
Theoretical and Applied Informatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Multichannel Receiver of the Experimental FM Based Passive Radar Using Software Defined Radio Technology
Autorzy:
Szlachetko, B.
Lewandowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/226436.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
SDR
passive radar
GNU Radio
USRP
Opis:
In this paper we present results of research on multichannel receiver using Software Defined Radio technology. This receiver is a part of the experimental FM based passive radar being designed. The hardware platform of the receiver consists of the Universal Software Defined Radio Peripheral devices. In the paper we propose modifications of the USRP's FPGA configuration and GNU Radio code. These modifications allow for developing six/nine synchronous input channel receiver based on two/tree USRPs respectively. Issues of synchronization of separate USRP devices by assuring synchronous sampling were presented. We also propose the solution of the problem of the alignment of the data streams being sent from USRP devices via USB to the PC host.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 4; 301-306
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Bacterial Disease on Bluberry (Vaccinium Corymbosum) Caused by Pseudomonas Spp.
Autorzy:
Kaluzna, M.
Pulawska, J.
Meszka, B.
Powiązania:
https://bibliotekanauki.pl/articles/65373.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
In 2011, leaf spot disease was observed on the blueberry (Vaccinium corymbosum) cv. Nelson growing on a commercial field located in Central Poland. The disease symptoms could be seen as russet brown, irregular spots. The diameter of the spots was 0.3-0.5 cm, and the spots often coalesced. From these leaf spots, a fluorescent bacterium was repeatedly isolated in almost pure culture. Polymerase chain reaction (PCR) using primers Ps-for and Ps-rev, specific for Pseudomonas spp. confirmed that they belong to this genus. Based on LOPAT tests [levan production from sucrose (L), presence of oxidase (O), pectolytic activity on potato (P), the presence of arginine dihydrolase (A), hypersensitivity reaction on tobacco (T)], 6 isolates were classified to the LOPAT group Ib - group of Pseudomonas syringae subsp. savastanoi and Pseudomonas delphini, and one isolate to group Ia - P. syringae. All isolates caused a hypersensitivity reaction on tobacco plants, and symptoms similar to those under natural conditions, when young leaves of blueberry cv. Nelson were inoculated. Sequence analysis of 16S rRNA and rpoB genes showed the highest similarity of 6 studied strains to the species P. avellanae. Further taxonomic study is necessary to enable definitive classification of these isolates. It is the first time that a bacterial disease caused by the Pseudomonas spp. was observed in Poland.
Źródło:
Journal of Plant Protection Research; 2013, 53, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Design Methodology For Enhancing The Transient Loading Of Low Drop-out Regulators (LDRs)
Autorzy:
Abdel-Monem, Ahmed
El-Mashade, Mohamed B.
Dabbous, T. E.
Powiązania:
https://bibliotekanauki.pl/articles/227180.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low drop-out regulator
cross coupling
jumps of the load current
undershot
overshot
Opis:
A new simple design methodology which makes LDR output nearly insensitive to jumps of the load current for long times is proposed. This methodology is tested for more than 10⁴ seconds. Our procedure leans on cross coupling of the time second derivative of the LDR power transistor gate and drain voltages along with their currents. This technique keeps low values of these currents in order of nano or hundreds of micro amperes for undershot or overshot cases, respectively. The introduced methodology has been applied to a standard CMOS of 0.18μm technology for NMOS transistors and validated using MATLAB R2014a.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 2; 319-327
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new etching trace from the Savignone Conglomerate (Oligocene), NW Italy, probably produced by limpet gastropods
Autorzy:
Uchman, A.
Rattazzi, B.
Powiązania:
https://bibliotekanauki.pl/articles/139401.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bioerosion
ichnotaxonomy
fan delta
borings
attachment
limpet gastropods
bioerozja
ichnotaksonomia
ślimaki
Gastropoda
Opis:
A new ichnogenus and ichnospecies (Solealites ovalis) of etching trace is preserved on the surfaces of clasts from the Savignone Conglomerate (Oligocene) in the Palaeogene Piemonte Basin in NW Italy. It is a shallow, oval depression with a central elevation, which was produced probably by limpet gastropods and served as their home scar, but other gastropods or even sea anemones are not excluded as the trace makers. The conglomerate is interpreted as a deposit of a fan delta, whose clasts have been bioeroded in an intertidal and shallow subtidal shore zone and redeposited to the deeper sea.
Źródło:
Acta Geologica Polonica; 2018, 68, 4; 651-662
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new form of Boussinesq equations for long waves in water of non-uniform depth
Autorzy:
Szmidt, J.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/201637.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
long wave
Boussinesq equation
wave transformation
variable water depth
Opis:
The paper describes the non-linear transformation of long waves in shallow water of variable depth. Governing equations of the problem are derived under the assumption that the non-viscous fluid is incompressible and the fluid flow is a rotation free. A new form of Boussinesq-type equations is derived employing a power series expansion of the fluid velocity components with respect to the water depth. These non-linear partial differential equations correspond to the conservation of mass and momentum. In order to find the dispersion characteristic of the description, a linear approximation of these equations is derived. A second order approximation of the governing equations is applied to study a time dependent transformation of waves in a rectangular basin of water of variable depth. Such a case corresponds to a spatially periodic problem of sea waves approaching a near-shore zone. In order to overcome difficulties in integrating these equations, the finite difference method is applied to transform them into a set of non-linear ordinary differential equations with respect to the time variable. This final set of these equations is integrated numerically by employing the fourth order Runge - Kutta method.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 3; 631-643
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new look at the bivalve Anomia ephippium Linnæus, 1758 from the Miocene of the Central Paratethys: anexample from the Nowy Sącz Basin in Poland
Autorzy:
Studencka, B.
Powiązania:
https://bibliotekanauki.pl/articles/138893.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bivalvia
anomiidae
calcified byssus
Kamienica Nawojowska
Nowy Sącz Basin
Badenian
middle Miocene
Central Paratethys
małże
bisior
Nowy Sącz
baden
miocen środkowy
Paratetyda Środkowa
Opis:
For the first time, articulated shells of Anomia ephippium Linnæus, 1758, the bivalve species widely distributed in the Egerian–Late Badenian (latest early Oligocene to late middle Miocene) in the Central Paratethys, are described and illustrated. The most astonishing fact is the presence of a heavily calcified byssus that anchored the animal to hard substrates, which is still preserved inside the byssal notch. The investigated material derives from the Badenian (middle Miocene) Niskowa Formation in the Nowy Sącz Basin, a small intramontane basin situated in the Polish Outer Carpathians. Apart from articulated shells and left valves, the collected material contains some dozen of calcified byssi fixed to rigid substrate, SEM images of which are presented. Examination of the A. ephippium specimens stored in the Polish Academy of Sciences, Museum of the Earth in Warsaw revealed other Paratethyan records of anomiid calcified byssi attached to other specimens of A. ephippium. Finally, the paper provides an overview of the previous studies on the representatives of the genus Anomia Linnæus, 1758 from the Central Paratethys and its specific assignment.
Źródło:
Acta Geologica Polonica; 2018, 68, 4; 635-650
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Technology of TRIAD Cement-Free Castables – Practical Aspects
Autorzy:
Cygan, B.
Dorula, J.
Jezierski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2079821.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
refractory materials
new technology
refractory linings used
pouring device
materiały ogniotrwałe
nowe technologie
zastosowanie wykładzin ogniotrwałych
urządzenia do zalewania
Opis:
The article presents the new technology of the refractory materials used for the ladles and pouring devices. The aim for solving the majority of the problems that originated from the refractory lining was to develop the group of cement-free TRIAD products by Vesuvius company. The cement-free setting system in the TRIAD products eliminates calcium oxide (CaO) that occurs in low and extra low cement concretes resulting in its higher strength at higher temperatures. The features of the new cement-free castables were described. One of the most unique features of this technology is the porous material structure. Small venting microchannels are formed during the concrete setting process. These micro-channels allow for removing water vapor from the lining without affecting its refractory properties. On the other hand, the diameter of pores is so low that it disallows the penetration of slag and metal into the lining, extends its operating life at the same time facilitates cleaning and removing build-ups. The procedure of the preparation of these materials, as well as the method of building of the lining, were presented. An example of the practical use of these materials in the ductile cast iron foundry was presented, showing the advantages of the new refractory materials over the traditional ones.
Źródło:
Archives of Foundry Engineering; 2021, 21, 2; 94-98
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A nonlinear statistical approach for damping uncertainty propagation in structural dynamics
Nieliniowe modelowanie statystyczne niepewności tłumienia w dynamice konstrukcyjnej
Autorzy:
Tiliouine, B.
Chemali, B.
Powiązania:
https://bibliotekanauki.pl/articles/230868.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dynamika konstrukcji
niepewność
odpowiedź dynamiczna
symulacja Monte Carlo
model nieliniowy
model statystyczny
structure dynamics
uncertainty
dynamic response
Monte Carlo simulation
nonlinear model
statistical model
Opis:
The object of the present study is to investigate the influence of damping uncertainty and statistical correlation on the dynamic response of structures with random damping parameters in the neighbourhood of a resonant frequency. A Non-Linear Statistical model (NLSM) is successfully demonstrated to predict the probabilistic response of an industrial building structure with correlated random damping. A practical computational technique to generate first and second-order sensitivity derivatives is presented and the validity of the predicted statistical moments is checked by traditional Monte Carlo simulation. Simulation results show the effectiveness of the NLSM to estimate uncertainty propagation in structural dynamics. In addition, it is demonstrated that the uncertainty in damping indeed influences the system response with the effects being more pronounced for lightly damped structures, higher variability and higher statistical correlation of damping parameters.
Nieliniowy Model Statystyczny (NLSM) jest opracowany, aby skutecznie rozpowszechniać niepewność tłumienia w analizach dynamicznych, w celu przewidywania statystyki drugiego rzędu dla probabilistycznej odpowiedzi konstrukcji ze skorelowanymi parametrami tłumienia. Waga tłumienia losowego ze skorelowanymi parametrami oraz ich wpływ na wrażliwość szczytowej odpowiedzi konstrukcyjnej, omawiane są w świetle znaczących zakresów niepewności tłumienia oraz współczynników korelacji. Dodatkowo, wpływ korelacji statystycznej tłumienia na granice przybliżenia Liniowego Modelu Statystycznego (LSM) oraz na NLSM badany jest za pomocą Symulacji Monte Carlo.
Źródło:
Archives of Civil Engineering; 2016, 62, 1; 11-24
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A North American ammonite fauna from the late Middle Turonian of Vaucluse and Gard, southern France: the Romaniceras mexicanum, Prionocyclus hyatti and Coilopoceras cf. springeri association
Autorzy:
Amédro, F.
Robaszynski, F.
Matrion, B.
Devalque, C.
Powiązania:
https://bibliotekanauki.pl/articles/138974.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cretaceous
Turonian
Ammonites
Transgressive event
migration
North America
Southern France
kreda
turon
amonity
migracja
Ameryka Północna
Francja Południowa
Opis:
An unusual, exotic, ammonite fauna including Romaniceras mexicanum Jones, 1938, Prionocyclus hyatti (Stanton, 1894) and Coilopoceras cf. springeri Hyatt, 1903 is recorded from the late Middle Turonian of Vaucluse and Gard, southern France. It is the first record of this ammonite association outside the Gulf Coast region and the Western Interior of the United States of North America. Up to present, these species were considered as endemic to the Western Interior sea-way. The migration of numerous ammonites from North America to western Europe during the late Middle Turonian suggests it is linked to a transgressive event or to a short sea-level high.
Źródło:
Acta Geologica Polonica; 2016, 66, 4; 729-736
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel proteomic approach to analyse methionine oxidation reveals protein oxidation patterns in Arabidopsis seeds
Autorzy:
Meimoun, P.
Valot, B.
Job, D.
Bailly, C.
Powiązania:
https://bibliotekanauki.pl/articles/80575.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
reactive oxygen species
nucleic acid
protein
oxidation
methionine
methionine sulphoxide reductase
protein oxidation
Arabidopsis
seed
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Novel Software-Defined Networking Controller : the Distributed Active Information Model (DAIM)
Autorzy:
Pupatwibul, P.
Banjar, A.
Hossain, M. I.
Braun, R.
Moulton, B.
Powiązania:
https://bibliotekanauki.pl/articles/226996.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
distributed network
OpenFlow
DAIM model
software defined networking
next generation networks
Opis:
This paper presents a new OpenFlow controller: the Distributed Active Information Model (DAIM). The DAIM controller was developed to explore the viability of a logically distributed control plane. It is implemented in a distributed way throughout a software-defined network, at the level of the switches. The method enables local process flows, by way of local packet switching, to be controlled by the distributed DAIM controller (as opposed to a centralised OpenFlow controller). The DAIM ecosystem is discussed with some sample code, together with flowcharts of the implemented algorithms. We present implementation details, a testing methodology, and an experimental evaluation. A performance analysis was conducted using the Cbench open benchmarking tool. Comparisons were drawn with respect to throughput and latency. It is concluded that the DAIM controller can handle a high throughput, while keeping the latency relatively low. We believe the results to date are potentially very interesting, especially in light of the fact that a key feature of the DAIM controller is that it is designed to enable the future development of autonomous local flow process and management strategies.
Źródło:
International Journal of Electronics and Telecommunications; 2018, 64, 2; 209-216
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A numerical approach to predict sulphur dioxide emissions during switchgrass combustion
Autorzy:
Peters, B.
Smuła-Ostaszewska, J.
Powiązania:
https://bibliotekanauki.pl/articles/185309.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biomass combustion
sulphur dioxide emissions
kinetic parameters
optimization
spalanie biomasy
emisja dwutlenku siarki
parametry kinetyczne
optymalizacja
Opis:
The demand for a net reduction of carbon dioxide and restrictions on energy efficiency make thermal conversion of biomass a very attractive alternative for energy production. However, sulphur dioxide emissions are of major environmental concern and may lead to an increased corrosion rate of boilers in the absence of sulfatation reactions. Therefore, the objective of the present study is to evaluate the kinetics of formation of sulphur dioxide during switchgrass combustion. Experimental data that records the combustion process and the emission formation versus time, carried out by the National Renewable Energy Institute in Colorado (US), was used to evaluate the kinetic data. The combustion of switchgrass is described sufficiently accurate by the Discrete Particle Method (DPM). It predicts all major processes such as heating-up, pyrolysis, combustion of switchgrass by solving the differential conservation equations for mass and energy. The formation reactions of sulphur dioxide are approximated by an Arrhenius-like expression including a pre-exponential factor and an activation energy. Thus, the results predicted by the Discrete Particle Method were compared to measurements and the kinetic parameters were subsequently corrected by the least square method until the deviation between measurements and predictions was minimised. The determined kinetic data yielded good agreement between experimental data and predictions.
Źródło:
Chemical and Process Engineering; 2013, 34, 1; 121-137
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Performance Study on Synchronous and Asynchronous Update Rules for A Plug-In Direct Particle Swarm Repetitive Controller
Autorzy:
Ufnalski, B.
Grzesiak, L. M.
Powiązania:
https://bibliotekanauki.pl/articles/141272.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
repetitive process control
particle swarm optimization (PSO)
synchronous and asynchronous update rules
dynamic optimization problem
repetitive disturbance rejection
optimal control
Opis:
In this paper two different update schemes for the recently developed plug-in direct particle swarm repetitive controller (PDPSRC) are investigated and compared. The proposed approach employs the particle swarm optimizer (PSO) to solve in on-line mode a dynamic optimization problem (DOP) related to the control task in the constant-amplitude constant-frequency voltage-source inverter (CACF VSI) with an LC output filter. The effectiveness of synchronous and asynchronous update rules, both commonly used in static optimization problems (SOPs), is assessed and compared in the case of PDPSRC. The performance of the controller, when synthesized using each of the update schemes, is studied numerically.
Źródło:
Archives of Electrical Engineering; 2014, 63, 4; 635-646
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Possibility to Improve Resistance of Cast-iron Hydraulic Valves to Cavitation Wear
Autorzy:
Orłowicz, A. W.
Tupaj, M.
Mróz, M.
Kupiec, B.
Jacek, M.
Radoń, M.
Powiązania:
https://bibliotekanauki.pl/articles/382203.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast iron
hydraulic valve
cavitation wear
plasma sprayed coating
sealing ring
żeliwo
zawór hydrauliczny
zużycie kawitacyjne
powłoka natryskiwana plazmowo
pierścień uszczelniający
Opis:
A common problem encountered in hydraulic valves is a progressing deterioration of tightness of their water flow cutting-off seats. The seats are provided usually with a copper-alloy insert joined mechanically with cast-iron valve housing. The problem of unreliability of such joints can be solved by providing surface of the seat with a coating, deposited with the use of HVOF method and resistant to abrasive and cavitation wear. The tests were carried out for a sealing-draining seat insert made of CuZn39Pb2Al brass used to date and a specimen taken from the cast-iron valve housing which was the substrate for a plasma-sprayed coating of powder containing 86.1% Cr, 7.2% Ni, and 6.7% C. The coating, 345 ± 15 μm thick, was characterized with good quality of bonding with cast-iron substrate and high compactness of the material. The cavitation wear test on materials used in the study were carried out with the use of Vibra-Cell ultrasonic liquid processor (Sonics) equipped with a piezoelectric probe operating at the frequency of 20 kHz. Based on profilograms taken along a line crossing centers of cavitation craters, measurements of the height parameter Rt, and microscopic observations of surfaces it has been found that the coating plasma-sprayed onto substrate of nodular cast iron demonstrated higher resistance to cavitation compared to copper-alloy inserts used so far in cast-iron hydraulic valves. Cavitation craters on the material used typically for valve seats to date were more distinctly outlined and deeper compared to craters observed on the coating. Larger were also sizes of local tear-outs which resulted in larger difference between the peaks line and the valleys line.
Źródło:
Archives of Foundry Engineering; 2018, 18, 4; 31-34
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Possibility to Improve Resistance of Cast-iron Wood Chip Fine Grinder Liners to Abrasive Wear
Autorzy:
Orłowicz, A. W.
Mróz, M.
Tupaj, M.
Kupiec, B.
Jacek, M.
Radoń, M.
Powiązania:
https://bibliotekanauki.pl/articles/380991.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ductile cast iron
WCCoCr coating
scratch test
żeliwo sferoidalne
powłoka WCCoCr
pomiar zarysowania
Opis:
The paper deals with the issue of potential for improvement of resistance of wood chip fine grinders to abrasive wear by providing them with WCCoCr coating applied with the use of atmospheric plasma spraying (APS). The study focused on establishing parameters of the technological process of spraying a 250–270 μm thick coating onto surface of ductile cast iron castings used to date as grinder linings. The presented data include results of microstructure examination, chemical composition analysis, HV hardness measurements, and scratch tests for both previous and new variant of linings. The obtained scratch test results indicate that the material of the coating is characterized with definitely lower susceptibility to scratching. The scratch made on coating was 75–84 μm wide and 7.2–8.2 μm deep, while the scratch on cast iron was distinctly wider (200–220 μm) and deeper (8.5–12.8 μm). In case of cast iron, the range of variability in scratch width and depth was definitely larger. This can be explained with large difference in hardness of individual components of microstructure of cast iron and significantly larger plastic deformation of cast iron compared to the coating revealed in the course of indenter motion over surfaces of the two materials. It has been found that application of WCCoCr coating offered better resistance of lining surfaces to scratching which can be considered a rationale for undertaking in-service tests.
Źródło:
Archives of Foundry Engineering; 2018, 18, 4; 35-38
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A preliminary study on some Chlorella spp. for biodiesel production
Autorzy:
Mohammady, N.G.-E.
El-Sayed, H.S.
El-Kassas, H.Y.
Elsherbiny, B.A.
Powiązania:
https://bibliotekanauki.pl/articles/80100.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biodiesel production
Chlorella
fatty acid
growth
lipid
oil
esterification
fatty acid methyl ester
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2017, 98, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A quarantine protocol against red palm weevil Rhynchophorus Ferrugineus (Olivier) (Coleptera: Curculiondae) in date palm
Autorzy:
Al-Shawaf, A.M.
Al-Shagag, A.
Al-Bagshi, M.
Al-Saroj, S.
Al-Bather, S.
Al-Dandan, A.M.
Abdallah, A.B.
Faleiro, J.R.
Powiązania:
https://bibliotekanauki.pl/articles/65957.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier), (Coleptera: Curculiondae) is a key pest of date palm in the Middle East. This weevil is currently being reported from over 50% of the date growing countries of the world. The date palm Phoenix dactylifera cropped area in the Middle East, has significantly increased during the last two decades where date palm is mainly propagated through offshoots. The red palm weevil larvae are often found in the offshoots, resulting in the spread of the pest and also its re-inoculation where RPW is already controlled. Currently, there are no quarantine protocols to ensure that date palm offshoots which are transported for planting, are free of RPW larvae. In this study, date palm offshoots were sprayed while still attached to the mother palm and also dipped separately with Fipronil 3.5% (Thripguard 35 SCTM) and Imidacloprid 35% (Confidor 350 SCTM) a day after detachment from the mother palm. Fipronil and Imidacloprid were tested at 0.008 % and 0.01%, respectively. Results revealed that dipping gave complete mortality of the larvae. Dipping was significantly better than spraying since spraying resulted in only partial mortality of the larvae. It was also seen that dipping offshoots in Fipronil 0.004% and 0.002% for 30 and 60 min, respectively, resulted in 100% mortality of the larvae tested. Further, toxicity studies resulted in complete mortality of larvae and adults that were exposed to offshoot tissue that was dipped in Fipronil at the above concentrations. For this reason, it is recommended to dip date palm offshoots in 0.004% Fipronil for 30 min before transporting to ensure complete mortality of the hidden larval stages, if any and complete certification and transport of the treated offshoots to the new planting site within 72 h of treatment.
Źródło:
Journal of Plant Protection Research; 2013, 53, 4
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A reassessment of the Pennsylvanian lycophyte cone Triplosporite Brown
Autorzy:
Thomas, B. A.
Bek, J.
Powiązania:
https://bibliotekanauki.pl/articles/138841.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Lepidostrobus
Lycospora
in situ spores
Triplosporite
Cones
Carboniferous
zarodniki
szyszka
karbon
Opis:
The type collection of the lycopsid cone species Triplosporite brownii Unger was re-examined to assess its in situ spores. The cones are monosporangiate with only microspores that possess both cingulum and zona. They equate to the dispersed miospore genus Lycospora and would be identified as Lycospora cf. pseudoannulata. Therefore, the genus Triplosporite Brown is shown to be a junior synonym to Lepidostrobus and a species emendation is given. A comparison is given with the other Lepidostrobus cones which yielded similar in situ microspores of the Lycospora pellucida Group.
Źródło:
Acta Geologica Polonica; 2014, 64, 2; 139-145
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of the importance of synchrophasor technology, smart grid, and applications
Autorzy:
Baba, Maveeya
Nor, Nursyarizal B.M.
Sheikh, Aman
Nowakowski, Grzegorz
Masood, Faisal
Rehman, Masood
Irfan, Muhammad
Arefin, Ahmed Amirul
Kumar, Rahul
Baba, A. Momin
Powiązania:
https://bibliotekanauki.pl/articles/2173713.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
phasor measurement unit
PMU
micro-PMU
Global Positioning System
GPS
optimal PMU placement
smart grid
SG
jednostka pomiaru fazorów
mikro-PMU
globalny system pozycjonowania
optymalne rozmieszczenie PMU
sieć inteligentna
Opis:
The electrical network is a man-made complex network that makes it difficult to monitor and control the power system with traditional monitoring devices. Traditional devices have some limitations in real-time synchronization monitoring which leads to unwanted behavior and causes new challenges in the operation and control of the power systems. A Phasor measurement unit (PMU) is an advanced metering device that provides an accurate real-time and synchronized measurement of the voltage and current waveforms of the buses in which the PMU devices are directly connected in the grid station. The device is connected to the busbars of the power grid in the electrical distribution and transmission systems and provides time-synchronized measurement with the help of the Global Positioning System (GPS). However, the implementation and maintenance cost of the device is not bearable for the electrical utilities. Therefore, in recent work, many optimization approaches have been developed to overcome optimal placement of PMU problems to reduce the overall cost by providing complete electrical network observability with a minimal number of PMUs. This research paper reviews the importance of PMU for the modern electrical power system, the architecture of PMU, the differences between PMU, micro-PMU, SCADA, and smart grid (SG) relation with PMU, the sinusoidal waveform, and its phasor representation, and finally a list of PMU applications. The applications of PMU are widely involved in the operation of power systems ranging from power system control and monitor, distribution grid control, load shedding control and analyses, and state estimation which shows the importance of PMU for the modern world.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 6; art. no. e143826
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simple Analytical Method for Determining Basic Hydrodynamic Characteristics of Hybrid Fluidized-Bed Air-Lift Apparatae
Autorzy:
Tabiś, B.
Boroń, D.
Powiązania:
https://bibliotekanauki.pl/articles/184975.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fluidized-bed
hydrodynamics
air-lift
hybrid apparatus
bioreactor
łóżko wodne
hydrodynamika
most lotniczy
urządzenie hybrydowe
bioreaktor
Opis:
A simple analytical method for determination of basic hydrodynamic characteristics of hybrid fluidized-bed air-lift devices was presented. These devices consist of two parts: a two-phase air-lift part and a two-phase liquid-solid fluidized-bed part. Forced circulation of fluid in the air-lift part is used for fluidization of solid particles in the fluidized-bed part. According to the opinion given in the literature, if such apparatus is used for aerobic microbiological processes, its advantage is lower shear forces acting on the biofilm immobilized on fine-grained material compared with shear forces in three-phase fluidized-bed bioreactors. Another advantage is higher biomass concentration due to its immobilization on fine particles, compared with two-phase airlift bioreactors. A method of calculating gas hold-up in the air-lift part, and gas and liquid velocities in all zones of the analyzed apparatus is presented.
Źródło:
Chemical and Process Engineering; 2017, 38, 1; 121-133
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simple analytical model of asymmetric rolling
Prosty model analityczny asymetrycznego walcowania
Autorzy:
Halloumi, A.
Desrayaud, Ch.
Bacroix, B.
Rauch, E.
Montheillet, F.
Powiązania:
https://bibliotekanauki.pl/articles/355090.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modelowanie asymetryczne
walcowanie blachy
walcowanie asymetryczne
asymmetric rolling
upper bound method
uniform strain field method
Opis:
An original analytical method is proposed for modeling asymmetric rolling (ASR) of metal sheet. It is based on a uniform strain field depending on a single optimization parameter, viz. the entry velocity of the sheet. The shear and normal strains associated with an ASR pass are derived analytically. Moreover, it is shown that the entry velocity almost coincides with the outer linear velocity of the slower roll, as far as ASR is sufficiently asymmetric. In that case, closed form formulae are available for the main rolling parameters such as the overall power dissipated and the two rolling torques. These results can be straighforwardly used for practical applications.
Zaproponowano oryginalną metodę analityczną do modelowania asymetrycznego walcowania blachy. Model jest oparty na jednolitym obszarze odkształcenia zależnym od jednego parametru optymalizacji tj. prędkości wejścia arkusza. Naprężenia ścinanające i normalne związane z przebiegiem asymetrycznego walcowania wyprowadzone są analitycznie. Co więcej pokazano, że prędkość wejścia niemal zbiega się z zewnętrzną prędkością liniową wolniejszego walca, o ile asymetryczne walcowanie jest wystarczająco asymetryczne. W takim przypadku zamknięte równania są dostępne dla głównych parametrów walcowania takich jak całkowita moc rozpraszania i dwa momenty obrotowe walcowania. Wyniki te mogą być bezpośrednio wykorzystywane do zastosowań praktycznych.
Źródło:
Archives of Metallurgy and Materials; 2012, 57, 2; 425-435
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simplified Design Methodology for MOSFET-Only Wideband Mixer
Autorzy:
Ortigueira, E.
Bastos, I.
Oliveira, L. B.
Oliveira, J. P.
Goes, J.
Powiązania:
https://bibliotekanauki.pl/articles/227194.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CMOS mixers
MOSFET-only circuits
Gilbert cell
active mixers
wideband mixers
Opis:
In this paper we present a MOSFET-only implementation of a wideband Gilbert Cell. The circuit uses a commongate topology for a wideband input match, capable to cover the Wireless Medical Telemetry Service (WMTS) frequency bands of 600 MHz and 1.4 GHz. In this circuit the load resistors are replaced by transistors in triode region, to reduce area and cost, and minimize the effects of process and supply variations and mismatches. In addition, we obtain a higher gain for the same DC voltage drop, with a reduced impact on the noise figure (NF). The performance of this topology is compared with that of a conventional mixer with load resistors. Simulation results show that a peak gain of 20.6 dB (about 6 dB improvement) and a NF about of 11 dB for the 600 MHz band. The total power consumption is 3.6 mW from a 1.2 V supply.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 4; 503-509
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Statistical Approach To Prediction Of The CMM Drift Behaviour Using A Calibrated Mechanical Artefact
Autorzy:
Cuesta, E.
Alvarez, B.
Sanchez-Lasheras, F.
Gonzalez-Madruga, D.
Powiązania:
https://bibliotekanauki.pl/articles/221090.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multivariate regression models
coordinate measuring machine
drift behaviour
calibration
Opis:
This paper presents a multivariate regression predictive model of drift on the Coordinate Measuring Machine (CMM) behaviour. Evaluation tests on a CMM with a multi-step gauge were carried out following an extended version of an ISO evaluation procedure with a periodicity of at least once a week and during more than five months. This test procedure consists in measuring the gauge for several range volumes, spatial locations, distances and repetitions. The procedure, environment conditions and even the gauge have been kept invariables, so a massive measurement dataset was collected over time under high repeatability conditions. A multivariate regression analysis has revealed the main parameters that could affect the CMM behaviour, and then detected a trend on the CMM performance drift. A performance model that considers both the size of the measured dimension and the elapsed time since the last CMM calibration has been developed. This model can predict the CMM performance and measurement reliability over time and also can estimate an optimized period between calibrations for a specific measurement length or accuracy level.
Źródło:
Metrology and Measurement Systems; 2015, 22, 3; 417-428
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Inclusions in Aluminum and Titanium Deoxidized 4130
Autorzy:
Tuttle, R. B.
Kottala, S.
Powiązania:
https://bibliotekanauki.pl/articles/379476.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
sand casting
inclusions
electrolytic extraction
inclusion characterization
stal
odlewanie piaskowe
wtrącenia
ekstrakcja elektrolityczna
Opis:
In this paper, the authors investigated the size distribution of titanium oxide (TiO2), titanium nitride (TiN) and titanium carbide (TiC) inclusions in a titanium deoxidized 4130 steel and compared it with the 4130 base alloy composition inclusions. TiN and TiC inclusions are of particular interest due to their role as heterogeneous nuclei for various phase reactions in steels. Two types of samples were prepared, a polished sample and a filtered sample. Electrolytic dissolution was employed to make the filter paper samples. The size range of titanium inclusions was found to be more than that of the non-metallic inclusions from 4130 base alloy heat. Titanium inclusions from the filter and polished samples were round in shape. TiC and TiN inclusions were not found in the electrolytic extraction samples. Inclusions and their chemistries were analyzed using scanning electron microscope and energy dispersive spectrometer. The inclusion size range was larger for the titanium deoxidized samples than the base alloy. However, in both steels the majority of inclusions had a size smaller than 10 μm.
Źródło:
Archives of Foundry Engineering; 2018, 18, 1; 129-134
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of molybdenum addition on W-Ni-Fe based heavy alloys sintered with spark plasma sintering
Autorzy:
Prasad, B. S. L.
Annamalai, R.
Powiązania:
https://bibliotekanauki.pl/articles/200737.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tungsten heavy alloys
sintering
mechanical properties
fracture mode
ciężkie stopy wolframu
spiekanie
właściwości mechaniczne
tryb pękania
Opis:
Tungsten heavy alloys comprising tungsten, nickel and ferrous were modified, where molybdenum was added in varying weight proportions keeping the ratio of Ni: Fe (8:2) constant. The powders were mixed in a high-energy ball mill and were further fabricated using the spark plasma sintering (SPS) method at a peak temperature of 1000°C with heating rate of 100°C/min. The details of the microstructure and mechanical properties of these various alloy compositions were studied. With the increasing weight composition of the Mo in the alloy, the relative density of the alloy increased with a significant improvement in all the mechanical properties. The yield strength (YS), ultimate tensile strength (UTS) and hardness improved significantly with increase in the proportion of Mo; however, a reduction in elongation percentage was observed. The maximum strength of 1250 MPa UTS was observed in the alloy with a Mo proportion of 24%. The heavy alloy unmixed with Mo has shown distinct white and grey regions, where white (W) grain is due to tungsten and grey region is a combinatorial effect of Ni and Fe. Upon addition of Mo, the white and gray phase differences started to minimize resulting in deep gray and black ‘C’-phase structures because of homogenization of the alloy. The main fracture mode found during this investigation in the alloys was inter-granular mode.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 2; 167-172
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Susceptibility and Evaluation of Causes of Cracks Formation in Braze-Weld Filler Metal in Lap Joints Aluminum – Carbon Steel Made with Use of CMT Method and High Power Diode Laser
Autorzy:
Adamiak, M.
Wyględacz, B.
Czupryński, A.
Górka, J.
Powiązania:
https://bibliotekanauki.pl/articles/958197.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
braze-welding
intermetallic compound phase
high power diode laser
brazing
Opis:
In this article results of studies on cracks formation susceptibility in braze-welded joints of thin aluminum sheets and double-sided zinc galvanized steel sheets for car body parts made by laser brazing with high power diode laser ROFIN DL 020 and CMT MIG-brazing, with filler material in form of powder and wire accordingly, were presented. Optimal welding parameters were determined by visual acceptance criteria. On joints made with optimal parameters further examinations were carried. Results of macro- and microscopic metallographic examinations, structural roentgenography, EDS microanalysis and hardness tests were presented. Causes of brittle intermetallic Fe-Al phases formation in Al-matrix filler metal in dissimilar aluminum – zinc plated carbon steel joints were pointed.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 4; 2113-2123
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on of Music Features Derived from Audio Recordings Examples – a Quantitative Analysis
Autorzy:
Dorochowicz, A.
Kostek, B.
Powiązania:
https://bibliotekanauki.pl/articles/178092.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
music genre
audio parametrization
music features
Opis:
The paper presents a comparative study of music features derived from audio recordings, i.e. the same music pieces but representing different music genres, excerpts performed by different musicians, and songs performed by a musician, whose style evolved over time. Firstly, the origin and the background of the division of music genres were shortly presented. Then, several objective parameters of an audio signal were recalled that have an easy interpretation in the context of perceptual relevance. Within the study parameter values were extracted from music excerpts, gathered and compared to determine to what extent they are similar within the songs of the same performer or samples representing the same piece.
Źródło:
Archives of Acoustics; 2018, 43, 3; 505-516
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A surface engineering approach applicable to concrete repair engineering
Autorzy:
Garbacz, A.
Courard, L.
Bissonnette, B.
Powiązania:
https://bibliotekanauki.pl/articles/202018.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
durability of concrete structure
repair
adhesion
surface roughness
microcracking
surface engineering
Opis:
The objective of the paper is to analyze the effect of substrate roughness and superficial microcraking upon adhesion of repair systems using concrete surface engineering approach. The results presented in this paper have been obtained within the framework of research projects performed to develop a better understanding of the factors affecting the adhesion of repair materials through a surface engineering approach. Based on the results of investigations, the authors showed that the durability and quality of concrete repairs depend to a large degree on the characteristics of the substrate. Mechanical preparation and profiling of the concrete surface to be repaired has to be balanced with potential co-lateral effects such as superficial cracking, too often induced as a result of inappropriate concrete removal method selection, and the loss of benefits due to better mechanical anchorage. The results obtained confirm also that Concrete Surface Engineering, as a scientific concept, will definitely contribute to shed more light on how to optimize repair bond, taking into account interactions between the materials at different observation scales.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 1; 73-84
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A survey of requirements for COVID-19 mitigation strategies
Autorzy:
Jamroga, Wojciech
Mestel, David
Roenne, Peter B.
Ryan, Peter Y. A.
Skrobot, Marjan
Powiązania:
https://bibliotekanauki.pl/articles/2086859.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
COVID-19
mitigation strategies
specification
multi-agent logic
strategia łagodzenia
specyfikacja
logika wieloagentowa
Opis:
The COVID-19 pandemic has influenced virtually all aspects of our lives. Across the world, countries have applied various mitigation strategies, based on social, political, and technological instruments. We postulate that multi-agent systems can provide a common platform to study (and balance) their essential properties. We also show how to obtain a comprehensive list of the properties by “distilling” them from media snippets. Finally, we present a preliminary take on their formal specification, using ideas from multi-agent logics.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 4; e137724, 1--10
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A System for Acoustic Field Measurement Employing Cartesian Robot
Autorzy:
Szczodrak, M.
Kurowski, A.
Kotus, J.
Czyżewski, A.
Kostek, B.
Powiązania:
https://bibliotekanauki.pl/articles/221435.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cartesian robot
sound intensity
sound field
anechoic chamber
Opis:
A system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity(vector) quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other - with an artificial head in the sound field.
Źródło:
Metrology and Measurement Systems; 2016, 23, 3; 333-343
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A systemic review of existing serological possibilities to diagnose canine osteoarthritis with a particular focus on extracellular matrix proteoglycans and protein
Autorzy:
Shahid, M.
Manchi, G.
Slunsky, P.
Naseer, O.
Fatima, A.
Leo, B.
Raila, J.
Powiązania:
https://bibliotekanauki.pl/articles/30755.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Extra-cellular matrix (ECM) components are important and their stabilization is significant in maintaining normal healthy joint environment. In osteoarthritis (OA), ECM components are altered and indicate disease progression. The joint ECM is composed of proteoglycans (aggrecan, perlecan, inter α-trypsin inhibitor), glycoproteins (fibronectin, lubricin, COMP) and collagen types (most abundantly collagen type II) which represent structural and functional transformation during disease advancement. ECM investigation revealed significant biomarkers of OA that could be used as a diagnostic and therapeutic tool in different canine orthopedic diseases. This review deliberates our current findings of how the components of ECM change at the molecular level during disease progression in canine OA.
Źródło:
Polish Journal of Veterinary Sciences; 2017, 20, 1
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A tool to measure maturity of an employee suggestion scheme
Autorzy:
Lasrado, F.
Gomišček, B.
Powiązania:
https://bibliotekanauki.pl/articles/407046.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
quality management
measurement
model
system
Employee Suggestion Scheme
innovation
Opis:
Employee Suggestion Schemes have been used in organizations for a long time due to the fact that they enable fostering of creative ability of employees. However, they must be used effectively and in a sustainable manner to better the creativity and innovation capacity of organizations in order to improve competitive advantage. Therefore there is a need to understand the maturity of Employee Suggestion Schemes. This paper proposes a new, structured evaluation tool for assessing an organizational Employee Suggestion Scheme maturity. It suggests five building blocks: Leadership and Work Environment, System Capability, System Effectiveness, Organizational Encouragement and System Barriers, each of them characterized by several relevant indicators and an assessment/grading scale in order for an organization to be able to determine the maturity level of their Employee Suggestion Scheme as: Initial stage, Development stage or Advanced stage. Organizations should apply this tool to assess the maturity level of their Employee Suggestion Scheme and draw a roadmap for its improvements.
Źródło:
Management and Production Engineering Review; 2015, 6, 2; 4-13
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A zero-dimensional model used as a basis for numerical modelling of OP-650 boiler
Zerowymiarowy model kotła jako podstawa do obliczeń numerycznych kotła OP 650
Autorzy:
Hernik, B.
Pronobis, M.
Powiązania:
https://bibliotekanauki.pl/articles/172845.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power boiler
OP650 boiler
zero-dimensional model
CFD modelling
numerical modelling
kocioł energetyczny
kocioł OP-650
model zero-wymiarowy
modelowanie CFD
modelowanie numeryczne
Opis:
The numerical modelling of power boiler furnaces is often performed in the engineering practice. Quite often, however, the balance calculations of the entire boiler are not carried out. In this case, the flue gas temperature at the furnace outlet results from the numerical model and depends on the adopted assumptions (e.g. wall fouling or emissivity). However, the value determined in this way may be wrong, and the presented calculation method makes it impossible to verify it. One of the ways to improve the numerical model accuracy is the verification of the flue gas temperature at the furnace outlet value by calculations fully balanced by a zero-dimensional (0D) model based on measuring data. The numerical calculations should be carried in such a way that the average temperature at the furnace outlet in the computational fluid dynamical (CFD) model equals the temperature obtained from the 0D model. At the same time, the matching of this temperature should result from carefully selected assumptions of the numerical model, which have to correspond to the actual phenomena occurring in the furnace. This model presents the verification of the CFD model for the OP-650 boiler of a 225 MWel power unit. The results of numerical modelling of boiler according to non-premixed combustion model with mixture fraction/PDF (probability density function) approach was presented. Also numerical modelling of boiler with species transport model with volumetric reactions and finite rate chemistry was done.
W praktyce inżynierskiej często wykonywane jest numeryczne modelowanie palenisk kotłów energetycznych, przy czym często nie prowadzi się obliczeń bilansowych całego kotła. Temperatura spalin na wylocie z paleniska wynika wówczas z modelu numerycznego i zależy od przyjętych założeń (np. zanieczyszczenie ścian lub ich emisyjność). Tak wyznaczona wartość temperatury może jednak być błędna, a opisany sposób liczenia uniemożliwia jej weryfikację. Sposobem na poprawę dokładności modelu numerycznego jest weryfikacja temperatury spalin na wylocie z paleniska za pomocą w pełni zbilansowanych obliczeń modelem 0-wymiarowym opartym na danych pomiarowych. Obliczenia numeryczne powinny być tak prowadzone, aby średnia temperatura na wylocie z komory paleniskowej kotła w modelu CFD była równa temperaturze uzyskanej z modelu zerowymiarowego. Jednocześnie dopasowanie tej temperatury powinno wynikać z odpowiednio dobranych założeń modelu numerycznego, które muszą odpowiadać realnemu przebiegowi zjawisk zachodzących w palenisku. W niniejszej pracy dokonano opisanej weryfikacji modelu CFD dla kotła OP 650 do bloku 225 MWel. Przedstawiono wyniki modelowania numerycznego kotła wg algorytmu mixture fraction/PDF - z wykorzystaniem modelu spalania non-premixed oraz wyniki dla modelu opartego na reakcjach objętościowych z wykorzystaniem modelu finite-rate/eddy-dissipation.
Źródło:
Archiwum Energetyki; 2012, 42, 2; 17-26
0066-684X
Pojawia się w:
Archiwum Energetyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Abrasive wear of AlSi12-Al2O3 Composite materials manufac tired by pressure infiltration
Autorzy:
Kremzer, M.
Dziekońska, M.
Sroka, M.
Tomiczek, B.
Powiązania:
https://bibliotekanauki.pl/articles/354917.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
abrasive wear
composite materials
pressure infiltration
Opis:
The aim of this study is to investigate tribological properties of EN AC-AlSi12 alloy composite materials matrix manufactured by pressure infiltration of Al2O3 porous preforms. In the paper, a technique of manufacturing composite materials was described in detail as well as wear resistance made on pin on disc was tested. Metallographic observations of wear traces of tested materials using stereoscopic and confocal microscopy were made. Studies allow concluding that obtained composite materials have much better wear resistance than the matrix alloy AlSil2. It was further proved that the developed technology of their preparation consisting of pressure infiltration of porous ceramic preforms can find a practical application.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 3; 1255-1260
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accumulation and translocation heavy metals in hyperaccumulating plants (Brassica juncea v. Malopolska) exposed to Pb, Cu, Cd and Zn
Autorzy:
Malecka, A.
Piechalak, A.
Kutrowska, A.
Hanc, A.
Baralkiewicz, D.
Tomaszewska, B.
Powiązania:
https://bibliotekanauki.pl/articles/80141.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
heavy metal
translocation
accumulation
hyperaccumulation
Brassica juncea
phytoremediation
phytotoxic damage
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 3
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accuracy of the photogrametric measuring system for large size elements
Autorzy:
Grzelka, M.
Budzik, G.
Marciniak, L.
Gapiński, B.
Powiązania:
https://bibliotekanauki.pl/articles/379891.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
photogrammetry
coordinate measuring technique
maximum permissible error
size measurement
optical coordinate measuring system
fotogrametria
współrzędnościowa technika pomiarowa
błąd maksymalny dopuszczalny
pomiar wielkości
optyczna współrzędnościowa technika pomiarowa
Opis:
The aim of this paper is to present methods of estimating and guidelines for verifying the accuracy of optical photogrammetric measuring systems, using for measurement of large size elements. Measuring systems applied to measure workpieces of a large size which often reach more than 10000mm require use of appropriate standards. Those standards provided by the manufacturer of photogrammetric systems are certified and are inspected annually. To make sure that these systems work properly there was developed a special standard VDI / VDE 2634, "Optical 3D measuring systems. Imaging systems with point - by - point probing. " According to recommendations described in this standard research on accuracy of photogrametric measuring system was conducted using K class gauge blocks dedicated to calibrate and test accuracy of classic CMMs. The paper presents results of research of estimation the actual error of indication for size measurement MPEE for photogrammetric coordinate measuring system TRITOP.
Źródło:
Archives of Foundry Engineering; 2011, 11, 2 spec.; 75-80
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active Stabilization of the Beam Pointing of a High- Power KrF Laser System
Autorzy:
Barna, A.
Földes, I. B.
Bohus, J.
Szatmári, S.
Powiązania:
https://bibliotekanauki.pl/articles/221761.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diffraction-limited UV pulse
beam-pointing stabilization
long-term drift
photodiode
Opis:
An active beam-pointing stabilization system has been developed for a high-power KrF laser system to eliminate the long-term drift of the directional change of the beam in order to have a stable focusing to a high intensity. The control of the beam direction was achieved by a motor-driven mirror activated by an electric signal obtained by monitoring the position of the focus of the output beam. Instead of large sized UV-sensitive position sensitive detectors a simple arrangement with scatter plates and photodiodes are used to measure the directionality of the beam. After the beam stabilization the long-term residual deviation of the laser shots is ~14 μrad, which is comparable to the shot-to-shot variation of the beam (~12 μrad). This deviation is small enough to keep the focal spot size in a micrometer range when tightly focusing the beam using off-axis parabolic mirrors.
Źródło:
Metrology and Measurement Systems; 2015, 22, 1; 165-172
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active suspension system with integrated electrical tubular linear motor: design, control strategy and validation
Autorzy:
Thul, A.
Eggers, D.
Riemer, B.
Hameyer, K.
Powiązania:
https://bibliotekanauki.pl/articles/141477.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active vehicle suspension
tubular linear electric drive
electric motor control
Opis:
This paper focuses on the design and control of an active suspension system, where a tubular linear motor is integrated into a spring damper system of a vehicle. The spring takes up the weight of the vehicle. Therefore the electric linear motor can be designed very compact as it has to provide forces to adjust the damping characteristic only. Design and construction of the active suspension system, a control strategy and validation measurements at a test bench are presented.
Źródło:
Archives of Electrical Engineering; 2015, 64, 4; 605-616
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activity of aspartate aminotransferase and alanine aminotransferase within winter triticale seedlings infested by grain aphid (Sitobion avenae F.)
Autorzy:
Sempruch, C.
Leszczynski, B.
Chrzanowski, G.
Filipczuk, A.
Czerniewicz, P.
Wolska, K.
Powiązania:
https://bibliotekanauki.pl/articles/66072.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Amino acid level is well known indicator of plant resistance to aphids. Our earlier studies showed that grain aphid (Sitobion avenae F.) infestation caused changes in the activity of the enzymes connected with amino acid biosynthesis and the transformation to defensive secondary metabolites within triticale tissues. However, there are not data on the significance of aminotransferases in these processes. The aim of our study was the quantification of changes in the activity of aspartate aminotransferase (AspAT) and alanine aminotransferase (AlaAT) in winter triticale seedlings caused by the feeding of the grain aphid. The study results showed that aphid feeding caused an increase in AlaAT activity and a decrease in AspAT activity within tissues of the triticale. The induced mechanisms of the triticale resistance to the grain aphid are discussed.
Źródło:
Journal of Plant Protection Research; 2012, 52, 3
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activity of resveratrol on the influence of aflatoxin B1 on the testes of Sprague dawley rats
Autorzy:
Omur, A.D.
Yildirim, B.
Saglam, Y.S.
Comakli, S.
Ozkaraca, M.
Powiązania:
https://bibliotekanauki.pl/articles/2087503.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aflatoxin B1
rat
resveratrol
sperm
Źródło:
Polish Journal of Veterinary Sciences; 2019, 2; 313-320
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activity of selected components of antioxidant system in grass pea and yellow lupine protoplasts after enzymatic isolation
Autorzy:
Wiszniewska, A.
Piwowarczyk, B.
Powiązania:
https://bibliotekanauki.pl/articles/80679.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antioxidant
phenolic compound
grass pea
Lathyrus sativus
yellow lupin
Lupinus luteus
peroxidase
radical scavenging activity
oxidative stress
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2015, 96, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activity of some elements of antioxidant system in legume protoplast after enzymatic isolation
Autorzy:
Wiszniewska, A.
Piwowarczyk, B.
Powiązania:
https://bibliotekanauki.pl/articles/951199.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
legume plant
protoplast
grass pea
Lathyrus sativus
yellow lupin
Lupinus luteus
enzyme isolation
homeostatic mechanism
oxygen metabolism
oxidative stress
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2015, 96, 1
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Activity of zinc in the liquid Bi-In-Sn-Zn alloys determined by Knudsen method
Pomiary aktywności cynku w ciekłych stopach Bi-In-Sn-Zn metoda efuzyjna Knudsena
Autorzy:
Zajączkowski, A.
Gąsior, W.
Onderka, B.
Powiązania:
https://bibliotekanauki.pl/articles/356445.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metoda Knudsena
aktywność cynku
cynk
quaternary system
activity of zinc
indium
tin
bismuth
zinc
vapour pressure
effusion method
Opis:
The Knudsen effusion method was used for measurements of mass loss rate of liquid Bi-In-Sn-Zn alloys, in the temperature range from 572 to 768 K. The studies were carried out for the alloys with the ratio of Bi:In:Sn equal 2:6:2, 2:2:6 and 8:1:1. The obtained results were used for the calculation of zinc vapour pressure over liquid Bi-In-Sn-Zn alloys and next the activity of zinc in the Bi-In-Sn-Zn liquid phase. It was found that for the investigated alloys the activity of zinc shows the considerable positive deviation from the Raoult's law.
Stosując efuzyjna metodę Knudsena pomierzono szybkość ubytku masy cynku z ciekłych stopów Bi-In-Sn-Zn, w zakresie temperatur od 572 do 768 K. Badania zostały przeprowadzone dla stopów o stosunku zawartości molowych Bi:In:Sn równym 2:6:2, 2:2:6 oraz 8:1:1. Wyniki badań zostały wykorzystane do obliczenia równowagowej prężności par cynku nad ciekłymi stopami Bi-In-Sn-Zn, a następnie aktywności cynku. Stwierdzono, że dla zbadanych stopów aktywność cynku wykazuje znaczne dodatnie odstępstwa od prawa Raulta.
Źródło:
Archives of Metallurgy and Materials; 2012, 57, 3; 838-843
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acute phase response in the primiparous dairy cows after repeated percutaneous liver biopsy during the transition period
Autorzy:
Jawor, P.
Brzozowska, B.
Sloniewski, K.
Kowalski, Z.M.
Stefaniak, T.
Powiązania:
https://bibliotekanauki.pl/articles/30733.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The aim of this study was to evaluate the acute phase response of dairy cows to repeated liver biopsy in order to estimate the safety of this procedure during the transition period. Liver biopsies (up to 1000 mg of liver tissue) were conducted twice a day, 7 days before expected parturition and 3 days after calving. The number of needle insertions for each biopsy was recorded and was dependent on the amount of obtained tissue. Blood samples were taken on day 7 before expected parturition, then on days 3, 4, 7 and 14 after calving. Body temperature was measured daily in all 30 cows from day 3 until day 14 after calving. The concentrations of haptoglobin, serum amyloid A, fibrinogen and interleukin-6 were determined in serum and plasma. In 16.7% of cows, the rectal body temperature rose by ≥ 0.5oC on the day after liver biopsy. Although the concentrations of haptoglobin, serum amyloid A and fibrinogen increased significantly after calving (p<0.01), there was no influence of the number of biopsies on the acute phase reaction and repeated biopsy during the transition period had no effect on body temperature. Therefore, the procedure may be regarded as safe for cows during the transition period.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 2
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive backstepping control, synchronization and circuit simulation of a 3-D novel jerk chaotic system with two hyperbolic sinusoidal nonlinearities
Autorzy:
Vaidyanathan, S.
Volos, C.
Pham, V.-T.
Madhavan, K.
Idowu, B. A.
Powiązania:
https://bibliotekanauki.pl/articles/230036.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chaos
jerk system
novel system
adaptive control
backstepping control
chaos synchronization
Opis:
In this research work, a six-term 3-D novel jerk chaotic system with two hyperbolic sinusoidal nonlinearities has been proposed, and its qualitative properties have been detailed. The Lyapunov exponents of the novel jerk system are obtained as L1 = 0.07765,L2 = 0, and L3 = −0.87912. The Kaplan-Yorke dimension of the novel jerk system is obtained as DKY = 2.08833. Next, an adaptive backstepping controller is designed to stabilize the novel jerk chaotic system with two unknown parameters. Moreover, an adaptive backstepping controller is designed to achieve complete chaos synchronization of the identical novel jerk chaotic systems with two unknown parameters. Finally, an electronic circuit realization of the novel jerk chaotic system using Spice is presented in detail to confirm the feasibility of the theoretical model.
Źródło:
Archives of Control Sciences; 2014, 24, 3; 375-403
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive sliding mode formation control of multiple underwater robots
Autorzy:
Das, B.
Subudhi, B.
Pati, B. B.
Powiązania:
https://bibliotekanauki.pl/articles/229471.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AUV
SMC
passivity
cooperative control
Opis:
This paper proposes a new adaptive sliding mode control scheme for achieving coordinated motion control of a group of autonomous underwater vehicles with variable added mass. The control law considers the communication constraints in the acoustic medium. A common reference frame for velocity is assigned to a virtual leader dynamically. The performances of the proposed adaptive SMC were compared with that of a passivity based controller. To save the time and traveling distance for reaching the FRP by the follower AUVs, a sliding mode controller is proposed in this paper that drives the state trajectory of the AUV into a switching surface in the state space. It is observed from the obtained results that the proposed SMC provides improved performance in terms of accurately tracking the desired trajectory within less time compared to the passivity based controller. A communication consensus is designed ensuring the transfer of information among the AUVs so that they move collectively as a group. The stability of the overall closed-loop systems are analysed using Lyapunov theory and simulation results confirmed the robustness and efficiency of proposed controller.
Źródło:
Archives of Control Sciences; 2014, 24, 4; 515-543
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adhesion of Malassezia pachydermatis of different growth type to canine epithelial cells
Autorzy:
Florek, M.
Krol, J.
Staroniewicz, Z.
Bazanow, B.
Powiązania:
https://bibliotekanauki.pl/articles/30354.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
A total of 100 Malassezia pachydermatis strains recovered from skin and mucosal membranes of dogs were evaluated for their adhesive properties. Two types of growth, related to colony morphology on Sabouraud agar, were observed (type I and II). The mean number of fungal cells attaching to canine buccal epithelial cells was found to be 17. The number of adhered cells was greater (statistically significant at the level of p < 0.01) in strains belonging to the type I.
Źródło:
Polish Journal of Veterinary Sciences; 2014, 17, 2; 365-366
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adrenergic control of pinealocyte chondriome - an in vitro study
Autorzy:
Przybylska-Gomowicz, B.
Lewczuk, B.
Ziolkowska, N.
Prusik, M.
Powiązania:
https://bibliotekanauki.pl/articles/31742.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Norepinephrine released from sympathetic innervation plays the main role in the regulation of melatonin secretion in mammalian pinealocytes. The present study was conducted for the following reasons: 1) to establish whether the pinealocyte chondriome is controlled by norepinephrine, 2) to determine the effect of adrenergic stimulation on mitochondria, and 3) to characterize adrenoceptors involved in the regulation of the chondriome. The static organ culture of the pineal gland was used. The explants were incubated for 5 consecutive days in control medium and between 20:00 and 08:00 in medium with the presence of 10 μM norepinephrine – adrenergic agonist; isoproterenol – beta-adrenoceptor agonist; cirazoline, methoxamine, M-6364 – alfa1 – adrenoceptors agonists or PMA – activator of PKC. The explants were then subjected to ultrastructural examination and morphometric analysis. The incubation of explants in the presence of norepinephrine or isoproterenol caused a decrease in the relative volume and the numerical density of mitochondria and induced an increase in the percentage of free mitochondria in pinealocytes. Significant changes in these parameters were not observed after treatment with methoxamine, cirazoline, M-6463 and PMA. The results obtained show that the chondriome of pig pinealocytes is controlled by norepinephrine acting via beta-adrenoceptors. Adrenergic stimulation, repeated for five consecutive days of organ culture, causes a decrease in the number of mitochondria and a shift in the distribution of mitochondria from the form of networks and filaments into the form of single particles. This indicates the intensive remodeling of the mitochondria network, which is closely linked to the metabolic status of the cell.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption in Perfect Mixing Tank – Comparison of Exact and Approximate Kinetic Models
Autorzy:
Kupiec, K.
Gwadera, M.
Larwa, B.
Powiązania:
https://bibliotekanauki.pl/articles/185543.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
przybliżone równanie kinetyczne
adsorpcja w naczyniu
approximate kinetic equation
adsorption in vessel
Opis:
Periodic adsorption in a perfect mixing tank of a limited volume was considered. It was assumed that the adsorption rate is limited by diffusion resistance in a pellet. The approximate model of diffusion kinetics based on a continued fraction approximation was compared with the exact analytical solution. For the approximate model an algorithm was developed to determine a temporal variation of the adsorbate concentration in the pellet. The comparison was made for different values of the adsorbent load factor. In the numerical tests different shapes of pellets were considered. Both the numerical tests as well as our own experimental results showed that the approximate model provides results that are in good agreement with the exact solution. In the experimental part of this work adsorption of p-nitrophenol and acetic acid from aqueous solutions on cylindrical pellets of activated carbon was conducted.
Źródło:
Chemical and Process Engineering; 2014, 35, 3; 277-291
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption with chemical reaction in porous catalyst pellets under alternate concentration fields. Uniform temperature case
Autorzy:
Bizon, K.
Tabiś, B.
Powiązania:
https://bibliotekanauki.pl/articles/185479.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
catalyst pellets
reaction
diffusion
adsorption
dynamics
peleta katalityczna
reakcja
dyfuzja
adsorpcja
dynamika
Opis:
The work concerns the dynamic behaviour of a porous, isothermal catalyst pellet in which a simultaneous chemical reaction, diffusion and adsorption take place. The impact of the reactant adsorption onto the pellet dynamics was evaluated. A linear isotherm and a non-linear Freundlich isotherm were considered. Responses of the pellet to sinusoidal variations of the reactant concentration in a bulk gas were examined. It was demonstrated that the dynamics of the pellet is significantly affected both by accounting for the adsorption and by the frequency of the bulk concentration variations. The sorption phenomenon causes damping of the concentration oscillations inside the pellet and damping of its effectiveness factor oscillations. Depending on the frequency of the concentration oscillations in the bulk, the remarkable oscillations can involve an entire volume of the pellet or its portion in the vicinity of the external surface.
Źródło:
Chemical and Process Engineering; 2016, 37, 4; 473-484
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Al-Si-Re Alloys Cast by the Rapid Solidification Process
Stopy Al-Si-Re odlewane metodą rapid solidification
Autorzy:
Szymanek, M.
Augustyn, B.
Kapinos, D.
Żelechowski, J.
Bigaj, M.
Powiązania:
https://bibliotekanauki.pl/articles/356571.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium alloy
rapid solidification
grain refinement
ultrafine structure
stop aluminium
szybka krystalizacja
rozdrobnienie ziarna
rozdrobnienie struktury
Opis:
The aim of the studies described in this article was to present the effect of rare earth elements on aluminium alloys produced by an unconventional casting technique. The article gives characteristics of the thin strip of Al-Si-RE alloy produced by Rapid Solidification (RS). The effect of rare earth elements on structure refinement, i.e. on the size of near-eutectic crystallites in an aluminium–silicon alloy, was discussed. To determine the size of crystallites, the Scherrer X-ray diffraction method was used. The results presented capture relationships showing the effect of variable casting parameters and chemical composition on microstructure of the examined alloys. Rapid Solidification applied to Al-Si alloys with the addition of mischmetal (Ce, La, Ne, Pr) refines their structure.
Celem badań opisanych w artykule było przedstawienie wpływu pierwiastków metali ziem rzadkich na stopy aluminium otrzymywane niekonwencjonalną metodą odlewniczą. W artykule scharakteryzowano cienką taśmę ze stopu Al-Si-RE wytworzoną metodą szybkiej krystalizacji (Rapid Solidification). Przedstawiono wpływ pierwiastków metali ziem rzadkich na rozdrobnienie struktury - wielkość krystalitów okołoeutektycznego stopu aluminium - krzem. Do oznaczenia wielkości krystalitów wykorzystano rentgenowską dyfrakcyjną metodę Scherrera. Zaprezentowane wyniki ujmują zależności zmiennych parametrów odlewania i składu chemicznego na mikrostrukturę badanych stopów. Zastosowanie szybkiej krystalizacji dla stopów Al-Si z dodatkiem miszmetalu (Ce, La, Ne, Pr) powoduje rozdrobnienie ich struktury.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 4; 3057-3062
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algae in the annual sea ice at Hooker Island, Franz Josef Land, in August 1991
Autorzy:
Okolodkov, Yuri B.
Powiązania:
https://bibliotekanauki.pl/articles/2052736.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Franz Josef Land
phycology
sea-ice algae
Źródło:
Polish Polar Research; 1993, 14, 1; 25-32
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm for simultaneous parameter estimation of a multi-harmonic signal
Autorzy:
Petrović, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/221172.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
band-limited signals
fundamental frequency and Fourier coefficient estimation
signal reconstruction
finite-impulse-response (FIR) comb filter
Opis:
Estimating the fundamental frequency and harmonic parameters is basic for signal modelling in a power supply system. Differing from the existing parameter estimation algorithms either in power quality monitoring or in harmonic compensation, the proposed algorithm enables a simultaneous estimation of the fundamental frequency, the amplitudes and phases of harmonic waves. A pure sinusoid is obtained from an input multi-harmonic input signal by finite-impulse-response (FIR) comb filters. Proposed algorithm is based on the use of partial derivatives of the processed signal and the weighted estimation procedure to estimate the fundamental frequency, the amplitude and the phase of a multi-sinusoidal signal. The proposed algorithm can be applied in signal reconstruction, spectral estimation, system identification, as well as in other important signal processing problems. The simulation results verify the effectiveness of the proposed algorithm.
Źródło:
Metrology and Measurement Systems; 2012, 19, 4; 693-702
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Allelopathy in Solanaceae plants
Autorzy:
Mushtaq, W.
Siddiqui, M.B.
Powiązania:
https://bibliotekanauki.pl/articles/65653.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
plant growth
allelopathy
allelochemical
bioassay
plant extract
fraction
residue
Solanaceae
Opis:
Solanaceae plants have strong allelopathic potential, and therefore the action is confirmed through: a) bioassays with liquid or various solvent extracts and residues, b) fractionation, identification, and quantification of causative allelochemicals. Most assessments of allelopathy involve bioassays of plant or soil extracts, leachates, fractions, and residues which support seed germination and seedling growth in laboratory and greenhouse experiments. Plant growth is also stimulated below the allelopathic threshold, however severe growth reductions may be observed above the threshold concentration depending on the sensitivity of the receiving species. Generally, seedling growth is more sensitive than germination, particularly root growth. Some approaches showed that field soil collected beneath donor plants significantly reduced or somewhat promoted the growth of the recipients plants. Petri dish bioassays with aqueous extracts of different parts of donor plants showed considerable phytotoxic activities in a concentration-dependent manner with leaf aqueous extracts being most dominant. Delayed seed germination and slow root growth attributable to the extracts may be baffled with diffusion effects on the rate of imbibition, delayed initiation of germination, and particularly cell elongation; the main factor that is responsible for affecting root growth before and after the tip penetrates the testa. Light and electron microscopy extract analysis at the ultrastructural level are correctly investigated. Several Solanaceae plants have allelopathic potential, and therefore the activities, kinds and quantity of allelopathic compounds differ depending on the plant species. The incorporation of allelopathic substances into agricultural management might scale back the development of pesticides and reduce environmental deterioration.
Źródło:
Journal of Plant Protection Research; 2018, 58, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alternative, Direct Synthesis Method of the Ceramic Solid Solutions Based on BaTiO3 Through a High Energy Ball Milling
Autorzy:
Bąk, W.
Dulian, P.
Garbarz-Glos, B.
Czekaj, D.
Lisińska-Czekaj, A.
Powiązania:
https://bibliotekanauki.pl/articles/351595.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ceramics
mechanochemical synthesis
dielectric properties
phase transitions
ferroelectrics
Opis:
Polycrystalline samples BaTiO3 and the solid solutions Ba0.9 Sr0.1 TiO3, 0.9 Sr0.1 Ti0.9 Sn0.1 O3, Ba0.9 Sr0.1 Ti0.8 Sn0.2 O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure and morphology of the investigated samples were characterized by an X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization of electrical properties of the ceramics within the temperature range from –130°C to 250°C were performed by means of a dielectric spectroscopy method at the frequency ranging from 0.1 Hz to10 MHz. The diffusion of the paraelectric – ferroelectric phase transition and dielectric relaxation for ceramic samples are described.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 805-810
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminium AlMg1SiCu Matrix Composite Materials Reinforced with Halloysite Particles
Materiały kompozytowe o osnowie stopu aluminium AlMg1SiCu wzmacniane cząstkami haloizytowymi
Autorzy:
Dobrzański, L. A.
Tomiczek, B.
Pawlyta, M.
Król, M.
Powiązania:
https://bibliotekanauki.pl/articles/356380.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium matrix composites
halloysite nanotubes
mechanical alloying
hot extrusion
kompozyty z osnową aluminium
nanorurki haloizytowe
wyciskanie na gorąco
mechaniczne stopowanie
Opis:
In this work selected results of investigations of the new AlMg1SiCu matrix composite materials reinforced with halloysite particles manufactured by powder metallurgy techniques including mechanical alloying and hot extrusion are present. The composite materials obtained as a result of mechanical synthesis and hot extrusion are characterized with the structure of evenly distributed, disperse reinforcing phase particles in fine-grain matrix of AlMg1SiCu alloy, facilitate the obtainment of higher values of strength properties, compared to the initial alloy. The nanostructural composite materials reinforced with halloysite nanotubes with 15 mass % share are characterized by almost twice as higher micro-hardness - compared to the matrix material.
W pracy przedstawiono wybrane wyniki badań materiałów kompozytowych o osnowie stopu AlMg1SiCu wzmacnianych cząstkami hałoizytowymi wytworzonymi z wykorzystaniem metod metalurgii proszków, w tym mechanicznej syntezy i wyciskania na gorąco. Otrzymane w procesie mechanicznej syntezy i wyciskania na gorąco materiały kompozytowe charakteryzują się strukturą równomiernie rozłożonych, rozdrobnionych cząstek fazy wzmacniającej w drobnoziarnistej osnowie stopu AlMg1SiCu, sprzyjającą osiąganiu wyższych wartości właściwości wytrzymałościowych w porównaniu do stopu wyjściowego. Wytworzone nanostrukturalne materiały kompozytowe wzmacniane nanorurkami hałoizytowymi o udziale masowym 15% charakteryzują się - w porównaniu do materiału osnowy - ponad dwukrotnie większą mikrotwardością.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 1; 335-338
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amino acids content and basic chemical composition of roe deer (Capreolus capreolus L.) meat
Autorzy:
Cygan-Szczegielniak, D.
Janicki, B.
Powiązania:
https://bibliotekanauki.pl/articles/31855.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The aim of this study was to determine the chemical composition of roe deer meat considering the animals’ sex and age and to estimate the content of amino acids in the meat from two selected groups of the animals, i.e. 2-3-year-old males and females. A further goal was to assess the biological value of proteins as compared to the FAO standard. The study has revealed that in proteins from the roe deer muscle tissue the content of exogenous amino acids (in g/100g) is higher by 20-30% on average comparing to the level of amino acids, in the FAO/WHO (1973) standard protein. Among the endogenous amino acids, the highest (in g/100 g of protein) and the lowest concentrations were found for glutamic acid and proline, respectively. The research has also shown that roe deer meat possesses a high content of protein and a relatively low content of fat.
Źródło:
Polish Journal of Veterinary Sciences; 2012, 15, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An advanced planner for urban freight delivering
Autorzy:
Comi, A.
Buttarazzi, B.
Schiraldi, M.
Innarella, R.
Varisco, M.
Traini, P.
Powiązania:
https://bibliotekanauki.pl/articles/224160.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
urban freight
urban freight delivering
advanced planning
transport miejski
dostarczanie ładunków miejskich
planowanie zaawansowane
Opis:
The paper aims at introducing an advanced delivery tour planner to support operators in urban delivery operations through a combined approach which chooses delivery bays and delivery time windows while optimizing the delivery routes. After a literature review on tools for the management and the control of the delivery system implemented for optimizing the usage of on-street delivery bays, a prototypical tour delivery planner is described. The tool allows transport and logistics operators to book the delivery bays and to have real-time suggestions on the delivery tour to follow, through the minimization of the total delivery time. Currently, at development phase, the tool has been tested in a target zone, considering the road network and time/city delivering constraints and real-time data about vehicles location, traffic and delivery bay availability. The tool identifies the possible tours based on the delivery preferences, ranks the possible solutions according to the total route time based on information on the road network (i.e. travel time forecasts), performs a further optimization to reduce the total travel times and presents the user the best alternative along with the indications of which delivery bay to use in each delivery stop. The developed prototype is composed by two main parts: a web application that manages communication between the database and the road network simulation, and, an Android mobile App that supports transport and logistic operators in managing their delivering, pre trip and en route, showing and updating routing based on real-time information.
Źródło:
Archives of Transport; 2018, 48, 4; 27-40
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis of coal and coal mine methane co-combustion in an 140 t/h pulverized coal boiler
Autorzy:
Jagodzińska, K.
Hernik, B.
Pronobis, M.
Powiązania:
https://bibliotekanauki.pl/articles/175356.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Co-combustion
methane
heat transfer
power boiler
Opis:
The paper presents an attempt to evaluate the impact of coal and coal mine methane cocombustion on the physics of the heat exchange in an 140 t/h pulverized-coal boiler through an analysis of 21 combinations of the boiler operating parameters – three different boiler loads (50, 75, and 100%) and seven values of the fired gas thermal contribution (0–60%). The obtained results are the temperature distribution of flue gas and steam in the boiler characteristic points, the heat transfer coefficient values for the boiler individual elements expressing the nature of changes in the heat transfer and the change in the boiler efficiency depending on how much gas is actually fired. An increase in the amount of co-fired gas involves a temperature increase along the flue gas path. This is the effect of the reduction in the amount of heat collected by the evaporator in the furnace. For these reason, the flue gas temperature at the furnace outlet rises by 9 K on average per a 0.1 increment in the fired gas thermal contribution. The temperature rise improves the heat transfer in the boiler heat exchangers – for the first- and the secondstage superheater the improvement totals 2.8% at a 10 pp. increase in the fired gas thermal contribution. However, the rise in the flue gas temperature at the boiler outlet involves a drop in the boiler efficiency (by 0.13 pp. for a rise in the fired gas thermal contribution by 0.1).
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2017, 137; 3-18
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analysis of Laser-Welded Nicr-Ir and Nicr-Pt Micro Joints on Spark Plug Electrodes in Biogas-Fuelled Engines
Autorzy:
Grabas, B.
Tofil, S.
Napadłek, W.
Powiązania:
https://bibliotekanauki.pl/articles/351967.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microwelding
laser
spark plugs
refractory materials
biogas
Opis:
The paper deals with the laser beam welding of tips to central and side spark plug electrodes made of a nickel-chromium alloy. The tips attached to the central electrodes were made from a solid iridium wire 0.8 mm in diameter and 2 mm in length, while the tips connected to the side electrodes were made from a platinum wire 1.5 mm in diameter and 0.25 mm in thickness. In both cases, accurate positioning of the tips was required before they were resistance welded to the electrodes. Then, a fillet weld was produced with an Nd:YAG laser using single, partly overlapping conductive pulses. The laser welding was performed at different laser power levels and pulse durations. Metallographic sections of the joints were prepared to observe changes in the microstructure and determine their correlation with the changes in the process parameters. The results were used to select appropriate welding parameters for the materials joined. The microscopic analysis indicated welding imperfections such as micro cracks at the interface between the elements joined. The tips welded to the spark plug electrodes can help extend the service life of spark plugs in highly corrosive environments.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2B; 1163-1167
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analysis Of Tensile Test Results to Assess the Innovation Risk for an Additive Manufacturing Technology
Autorzy:
Adamczak, S.
Bochnia, J.
Kaczmarska, B.
Powiązania:
https://bibliotekanauki.pl/articles/221812.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
failure mode and effects analysis
static tensile test
measurement uncertainty
Opis:
The aim of this study was to assess the innovation risk for an additive manufacturing process. The analysis was based on the results of static tensile tests obtained for specimens made of photocured resin. The assessment involved analyzing the measurement uncertainty by applying the FMEA method. The structure of the causes and effects of the discrepancies was illustrated using the Ishikawa diagram. The risk priority numbers were calculated. The uncertainty of the tensile test measurement was determined for three printing orientations. The results suggest that the material used to fabricate the tensile specimens shows clear anisotropy of the properties in relation to the printing direction.
Źródło:
Metrology and Measurement Systems; 2015, 22, 1; 127-138
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analytical model of a system with priorities servicing a mixture of different elastic traffic streams
Autorzy:
Nowak, B.
Piechowiak, M.
Stasiak, M.
Zwierzykowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/201475.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
teletraffic engineering
analytical model
priorities
Opis:
This article proposes an analytical model of a system with priorities servicing a mixture of different elastic traffic streams. The model presented in the article was developed as the extension of earlier works published by the authors. It utilizes the concept of equivalent bandwidth and then, following bandwidth discretization, uses the dependencies introduced on the basis of the assumptions adopted for the generalized Kaufman-Roberts formula and for the model of a full-availability group with traffic compression. The article presents a possibility of using the proposed model to model the radio interface in a multi-service mobile network and provides an example of the above with the interface of an LTE network. Since the proposed model is an approximate one, the results of the calculations are compared with the results of simulations. A comparison of the results confirms an acceptable level of accuracy of the model. The model can be successfully used in the analysis and design of links and nodes of telecommunication and computer networks.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 2; 263-270
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An approximate mathematical model binding the height and position of lumbar vertebrae in the canine spine
Autorzy:
Wadowska, I.
Dzierzęcka, M.
Paśko, S.
Barszcz, K.
Bartyzel, B.J.
Powiązania:
https://bibliotekanauki.pl/articles/2087311.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lumbar vertebrae
spine
dogs
mathematical model
Źródło:
Polish Journal of Veterinary Sciences; 2020, 23, 2; 301-308
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Assessment of Appropriateness of the Choice of Parameters for Refractory Stampings Fabrication Process
Autorzy:
Orłowicz, A. W.
Mróz, M.
Tupaj, M.
Trytek, A.
Kupiec, B.
Korzeniowski, M.
Pająk, D.
Sondej, K.
Kozak, L.
Powiązania:
https://bibliotekanauki.pl/articles/382313.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die stamping
refractory materials
metal die
material density
tłoczenie
materiały ogniotrwałe
matryca
gęstość
Opis:
The paper presents results of an analysis of material density distribution in stampings press-moulded in metal dies from raw refractory materials based on alumina-magnesia-carbon aggregate. The stampings, fabricated on LAEIS HPF 1250 pressing machine, are blanks from which refractory precast shapes are manufactured by means of drying and firing. Samples for material density evaluation were cut out from test stampings with the use of diamond-reinforced disc. Density of the material was determined in thirteen layers of stampings denoted with letters A through M.
Źródło:
Archives of Foundry Engineering; 2016, 16, 2; 55-60
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An assessment of RFID applications in manufacturing companies
Autorzy:
Gładysz, B.
Powiązania:
https://bibliotekanauki.pl/articles/406856.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cyber-physical systems
RFID
decision making
Assessment of RFID Technology
Opis:
The meaning of Cyber Physical Systems and an Internet of Things with indication of RFID position in those concepts was outlined. Research program related to assessment of RFID technology was presented. Author deducted on problems related to RFID implementations and RFID essentially for logistics of manufacturing companies. Research goals and problems were formulated. Tools, techniques, models and methods that could be utilized were proposed and discussed. Research was focused on design of a new method to support early decision making phases for RFID application in logistics of manufacturing companies. Author stated that literature and practice lacks of complex method to answer if RFID is strategically important for the company, which processes should be RFID-supported, how RFID-supported processes should be designed and if RFID-support is rational. Framework for assessment of RFID technology with illustrative example was discussed.
Źródło:
Management and Production Engineering Review; 2015, 6, 4; 33-42
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Essay on Paradigms of Socioglobalistic at Sea and Coast
Autorzy:
Woźniak, Robert B.
Powiązania:
https://bibliotekanauki.pl/articles/520212.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
paradigm
globalization
socioglobalistic
sea
coast
communities
science
Opis:
Socioglobalistic at sea and coast deals with understanding and explaining the global problems of the modern world connected with maritime and around maritime matters. The social reality is presented in terms of objective and subjective determinants of individual and collective social relations at sea and connected with sea. The aim of the article is to present a broad scale of paradigms for new maritime sociology.
Źródło:
Roczniki Socjologii Morskiej; 2013, 22; 69-77
0860-6552
Pojawia się w:
Roczniki Socjologii Morskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An evaluation of practical applicability of multi-assortment production break-even analysis based on mining companies
Ocena praktycznej przydatności metod analizy wieloasortymentowego progu rentowności produkcji na przykładzie przedsiębiorstw górniczych
Autorzy:
Fuksa, D.
Trzaskuś-Żak, B.
Gołaś, Z.
Utrata, A.
Powiązania:
https://bibliotekanauki.pl/articles/218777.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analiza CVP
wieloasortymentowy próg rentowności
koszty
CVP analysis
multi-assortment break-even
costs
Opis:
In the practice of mining companies, the vast majority of them produce more than one product. The analysis of the break-even, which is referred to as CVP (Cost-Volume-Profit) analysis (Wilkinson, 2005; Czopek, 2003) in their case is significantly constricted, given the necessity to include multi-assortment structure in the analysis, which may have more than 20 types of assortments (depending on the grain size) in their offer, as in the case of open-pit mines. The article presents methods of evaluation of break-even (volume and value) for both a single-assortment production and a multi-assortment production. The complexity of problem of break-even evaluation for multi-assortment production has resulted in formation of many methods, and, simultaneously, various approaches to its analysis, especially differences in accounting fixed costs, which may be either totally accounted for among particular assortments, relating to the whole company or partially accounted for among particular assortments and partially relating to the company, as a whole. The evaluation of the chosen methods of break-even analysis, given the availability of data, was based on two examples of mining companies: an open-pit mine of rock materials and an underground hard coal mine. The selection of methods was set by the available data provided by the companies. The data for the analysis comes from internal documentation of the mines – financial statements, breakdowns and cost calculations.
W praktyce przedsiębiorstw górniczych, zdecydowana większość z nich wytwarza więcej niż jeden produkt. Analiza progu rentowności będąca elementem analizy CVP (Cost-Volume-Profit), w przypadku tych przedsiębiorstw jest znacznie utrudniona ze względu na konieczność uwzględnienia struktury asortymentowej w analizie, która, jak w przypadku kopalń odkrywkowych może mieć nawet powyżej dwudziestu rodzajów asortymentów (w zależności od uziarnienia) w ofercie sprzedaży. W artykule przedstawiono sposoby obliczania progów rentowności (ilościowych i wartościowych) zarówno przy produkcji jednoasortymentowej, jak i wieloasortymentowej. Złożoność problemu wyzna- czania progu rentowności przy produkcji wieloasortymentowej spowodowała wykształcenie wielu metod, a wraz z nimi różnych podejść do jego analizy, a w szczególności odmienne uwzględnianie kosztów stałych, które mogą być rozliczane w całości między poszczególne asortymenty, odnoszone do całego przedsiębiorstwa, bądź też w części rozliczone między poszczególne asortymenty, a w części odnoszone do przedsiębiorstwa, jako całości. Ocenę przydatności wybranych metod analizy progu rentowności, ze względu na dostępność danych, przeprowadzono na przykładzie dwóch przedsiębiorstw górniczych: kopalni odkrywkowej surowców skalnych oraz kopalni podziemnej węgla kamiennego. Wybór metod podyktowany był udostępnionymi przez analizowane przedsiębiorstwa danymi. Dane do analizy pochodzą z dokumentów wewnętrznych kopalń – sprawozdań finansowych, prowadzonych zestawień i kalkulacji kosztowych.
Źródło:
Archives of Mining Sciences; 2017, 62, 1; 33-44
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Evaluation of the use of Laser-Vibration Melting to Increase the Surface Roughness of Metal Objects
Analiza możliwości wykorzystania laserowo-wibracyjnego przetapiania do zwiększania chropowatości powierzchni elementów metalowych
Autorzy:
Grabas, B.
Powiązania:
https://bibliotekanauki.pl/articles/353962.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
laser melting
surface roughness
laser treatment
vibration
nucleate boiling
przetapianie laserowe
chropowatość powierzchni
obróbka laserowa
wibracja
zarodkowanie termiczne
Opis:
This paper presents preliminary, experimental results of a new, hybrid method of increasing the surface roughness of metal objects. In this new approach, metal objects are melted with a mobile laser beam while they are being rotated. A vibration generator provides circular vibrations with an amplitude of 3 mm, and the vibration plane is perpendicular to the moving laser beam. The melting tests were performed using flat carbon steel samples at a predetermined frequency of circular vibrations. The effects of laser power and laser beam scanning velocity on the melted shapes were studied. All laser melting procedures were performed at a vibration frequency of 105 Hz. The melted samples were subjected to microscopic evaluation and the Ra parameter, which characterises mean roughness, was measured using a profilometer. Melting metal samples with physically smooth surfaces (Ra = 0.21 µm) resulted in surface structures of varied roughness values, with Ra ranging from 5 µm to approximately 58 µm. The studies were undertaken to employ this technology for the purpose of passive heat exchange intensification of heating surfaces in practical applications.
W artykule zaprezentowano wstępne wyniki eksperymentalne nowej hybrydowej metody zwiększania chropowatości powierzchni elementów metalowych. W metodzie tej wykorzystuje się przetapianie ruchomą wiązką laserową elementów metalowych poddanych równocześnie wibracji kołowej. Generator drgań wytwarza wibrację kołową o amplitudzie 3 mm, a płaszczyzna wibracji jest prostopadła do osi przemieszczającej się wiązki laserowej. Próbom przetapiania przy ustalonej częstotliwości wibracji kołowej poddano płaskie próbki ze stali węglowej. Badano wpływ mocy laserowej oraz prędkości skanowania wiązki laserowej na kształt przetopień. Wszystkie przetopienia laserowe wykonywano przy częstotliwości wibracji f = 105 Hz. Otrzymane przetopy poddane zostały obserwacjom mikroskopowym oraz pomiarom profilometrycznym parametru Ra charakteryzującego średnią chropowatość. W wyniku przetapiania technicznie gładkich powierzchni próbek metalowych (Ra = 0,21 µm), uzyskano struktury o zróżnicowanych chropowatościach, dla których Ra mieścił się w przedziale od ok. 5 µm do ok. 58 µm. Badania prowadzono pod kątem potencjalnych możliwości stosowania tej technologii do pasywnej intensyfikacji wymiany ciepła powierzchni płyt grzewczych.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 1; 33-39
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An evaluation of turbulence model for vortex breakdown detection over delta wing
Autorzy:
Wibowo, S. B.
Sutrisno, -
Rohmat, T. A.
Powiązania:
https://bibliotekanauki.pl/articles/949942.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
turbulence models
vortex breakdown
delta wing
vortex core
computational fluid dynamics
CFD
roll-up vortex
modele turbulencji
awaria wirowa
skrzydło delta
rdzeń vortex
obliczeniowa mechanika płynów
wir zawijający
Opis:
An important phenomenon of delta wing is the mechanism of vortex core, which indicates the increase in lifting force until the occurrence of the vortex breakdown. The computational fluid dynamics (CFD) is very helpful in visualizing and providing analysis of the detailed data. The use of turbulent models will affect the quality of results in obtaining the vortex breakdown phenomenon. This study used several models of turbulence to capture the occurrence of vortex breakdown and compare it with experiments using water tunnel test facility. The results show that all turbulence models give good results at a low angle of attack (AoA), but at a high AoA the DES model gives the results closest to experimental ones with Cl error value of about 1 %. Taking into account the time required and the acceptable level of accuracy, the use of SST and k-ω models is an alternative option for use in the detection of vortex breakdown.
Źródło:
Archive of Mechanical Engineering; 2018, LXV, 3; 399-415
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An extension of Burzyński hypothesis of material effort accounting for the third invariant of stress tensor
Rozszerzenie hipotezy wytężenia burzyńskiego uwzględniające wpływ trzeciego niezmiennika tensora naprężenia
Autorzy:
Pęcherski, R. B.
Szeptyński, P.
Nowak, M.
Powiązania:
https://bibliotekanauki.pl/articles/351280.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
warunek plastyczności Burzyńskiego
kąt Lodego
trzeci niezmiennik dewiatora tensora naprężenia
Burzyński yield condition
strength differential effect
pressure sensitivity
Lode angle
third invariant of stress tensor deviator
Opis:
The aim of the paper is to propose an extension of the Burzyński hypothesis of material effort to account for the influence of the third invariant of stress tensor deviator. In the proposed formulation the contribution of the density of elastic energy of distortion in material effort is controlled by Lode angle. The resulted yield condition is analyzed and possible applications and comparison with the results known in the literature are discussed.
Celem pracy jest propozycja rozszerzenia hipotezy wytężenia Burzyńskiego dla uwzględnienia wpływu trzeciego niezmiennika dewiatora tensora naprężenia. W proponowanym sformułowaniu udział gęstości sprężystej energii odkształcenia postaciowego jest kontrolowany przez funkcję zależną od kąta Lodego. Wyprowadzony warunek plastyczności porównano ze znanymi wynikami z literatury oraz przedyskutowano jego możliwe zastosowania.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 2; 503-508
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Improved Approximation for DIPPR-Based Predicting Speed of Sound in Long-Chained n-Alkanes
Autorzy:
Postnikov, E. B.
Nedyalkov, Y. V.
Polishuk, I.
Powiązania:
https://bibliotekanauki.pl/articles/177788.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
n-alkanes
isothermal compressibility
speed of sound
Opis:
In this short communication, we revise a correlation for the saturated liquid isothermal compressibility based on the data available in DIPPR (Postnikov, 2016) which considers the molecular non-sphericity and addresses a problem of predicting speeds of sound in saturated long-chained alkanes. In addition, we correct a misprint appeared in the cited work and provide programming code used for the realisation of the proposed calculations.
Źródło:
Archives of Acoustics; 2018, 43, 3; 537-541
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved procedure for in vivo and in vitro propagation of Buxus hyrcana, an ornamental shrub critically at risk of extinction
Autorzy:
Negahdar, N.
Hashemabadi, D.
Kaviani, B.
Powiązania:
https://bibliotekanauki.pl/articles/80583.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ornamental shrub
Buxus hyrcana
endangered plant
plant growth regulator
rooting
stem cutting
tissue culture
indole-3-butyric acid
kinetin
in vitro propagation
in vivo
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2019, 100, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved resonant thermal converter based on micro-bridge resonator
Autorzy:
Dong, L.
Han, J.
Zhang, P.
Zhao, Z.
Cheng, B.
Han, D.
Powiązania:
https://bibliotekanauki.pl/articles/220878.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermoelectric transfer difference
micro-bridge resonator
thermal converter
bifilar heater
Opis:
This paper presents the design, fabrication and testing of an improved thin-film thermal converter based on an electro-thermally excited and piezo-resistively detected micro-bridge resonator. The resonant thermal converter comprises a bifilar heater and an opposing micro-bridge resonator. When the micro-bridge resonator absorbs the radiant heat from the heater, its axial strain changes, then its resonant frequency follows. Therefore the alternating voltage or current can be transferred to the equivalent DC quantity. A non-contact temperature sensing mechanism eliminates heat loss from thermopiles and reduces coupling capacitance between the temperature sensor and the heater compared with traditional thin-film thermal converters based on thermopiles. In addition, the quasi-digital output of the resonant thin-film thermal converter eliminates such problems as intensity fluctuations associated with analogue signals output by traditional thin-film thermal converters. Using the fast-reversed DC (FRDC) method, the thermoelectric transfer difference, which determines the frequency-independent part of the ac-dc transfer difference, is evaluated to be as low as 1.1 · 10-6. It indicates that the non-contact temperature sensing mechanism is a feasible method to develop a high-performance thermal converter.
Źródło:
Metrology and Measurement Systems; 2018, 25, 4; 715-725
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł

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