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Wyszukujesz frazę "Lewandowski, J." wg kryterium: Autor


Tytuł:
Inductive sensors for weighing of mass
Autorzy:
Lewandowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/220427.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inductive load cell
electronic scales
measuring system of mass
Opis:
A new method measuring of mass in electronic system of scales has been described. The main element of this system is inductive measuring load cell, which was compared with strain gauge load cell. The aim of the paper is described advantages of the inductive measuring system of mass and explain some main problems of this system. Digital correction of the mechanical errors of the beam like: hysteresis, creep material of the beam under constant load, influence of ambient temperature was described.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 323-334
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elongation cutoff technique: parallel performance
Metoda wydłużania w wariancie zrównoleglonym
Autorzy:
Korchowiec, J.
Lewandowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/305353.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
metody klasy O(N)
techniki fragmentacyjne
metoda wydłużania
order-N methods
fragmentation techniques
elongation method
Opis:
It is demonstrated that the elongation cutoff technique (ECT) substantially speeds up the quantum-chemical calculation at Hartree-Fock (HF) level of theory and is especially well suited for parallel performance. A comparison of ECT timings for water chains with the reference HF calculations is given. The analysis includes the overall CPU (central processing unit) time and its most time consuming steps.
Pokazano, że technika obcięcia, zastosowana w metodzie wydłużania istotnie przyspiesza obliczenia kwantowo-chemiczne w formaliźmie Hartreego-Focka (HF). Metoda ta sprawdza się wyjątkowo dobrze w obliczeniach przeprowadzanych na wielu procesorach. W pracy porównano zarówno całkowity czas obliczeń, jak i jego najbardziej czasochłonnych części, z tradycyjnym schematem obliczeniowym metody HF.
Źródło:
Computer Science; 2008, 9; 67-76
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of stress intensity factor in specimens with different fillet geometry subjected to bending
Autorzy:
Lewandowski, J.
Rozumek, D.
Powiązania:
https://bibliotekanauki.pl/articles/387467.pdf
Data publikacji:
2018
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
numerical method
fatigue crack growth
bending
Opis:
The article presents the maps of xx stress component and compares values of analytical and numerical calculations for the stress intensity factor range of welded specimens with fillet welds which subjected to cyclic bending. The tests were performed under constant value of moment amplitude Ma = 9.20 Nm and stress ratio R = σmin/ σmax = -1. The specimens were made of drag steel rod S355. The specimens were solid and welded. The numerical models were simulated with ABAQUS suite and numerical calculations performed with FRANC3D software.
Źródło:
Acta Mechanica et Automatica; 2018, 12, 1; 38-43
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics of back pain in Polish youth depending on place of residence
Autorzy:
Lewandowski, J.
Lukaszewska, K.
Powiązania:
https://bibliotekanauki.pl/articles/52220.pdf
Data publikacji:
2014
Wydawca:
Instytut Medycyny Wsi
Opis:
Introduction and objective. Spinal pain (SP) has become a very common problem in contemporary societies and occurs in adults, youths, and even children. The aim of the study was to determine whether the prevalence and characteristics of SP, as well as the determinants leading to SP in Polish youths, vary depending on the place of residence. The determinants considered were out-of-school physical activity (PA) and physical work (PW), time spent at a computer and TV, and the level of psychosocial development expressed as the level of anxiety-trait. The restricting effect of the experienced SP on everyday functioning of youths was also analysed. Materials and method. A cross-sectional, population-based study comprising 502 village residents (VR) and 1,593 city residents (CR) aged 13–19, residing in 3 random Polish provinces. The tools used were a custom-designed survey and the State-Trait Anxiety Inventory (STAI) filled by students during classes. Results. The frequency and localisation of SP, the time and circumstances in which SP episodes occur, as well as the influence of the pain on everyday functioning, are the same in youths living in villages and youths living in cities. Slight differences in the correlation between the prevalence of SP and determinants of SP development related to lifestyle depending on the place of residence were observed. However, in both VR and CR the occurrence of SP is significantly correlated negatively with the level of psychosocial development. Conclusions. At present, the conditions of living in a rural and in an urban environment in Poland pose no specific threat determining the occurrence of SP in youths, and increasing the negative effect of the pain on the functioning of youths.
Źródło:
Annals of Agricultural and Environmental Medicine; 2014, 21, 3
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simplified mathematical model of a U-tube steam generator under variable load conditions
Autorzy:
Laskowski, R.
Lewandowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/240139.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam generator
mathematical model under variable load conditions
wytwornica pary
model matematyczny
zmienne warunki obciążenia
Opis:
A steam generator in a nuclear power plant with a light water reactor is a heat exchanger, in which the heat is being transferred from the primary to the secondary loop (it links the primary and secondary loops). When the power plant is running, the inlet parameters (temperatures and mass flow rates) on both sides of the steam generator can change. It is important to know how the changes of these parameters affect the steam generator performance. The complexity of the processes taking place in the steam generator makes it difficult to create a simulator reflecting its performance under changed conditions. In order to simplify the task, the steam generator was considered as a ‘black box’ with the aim of examining how the changes of the inlet parameters affect the changes of the outlet ones. On the basis of the system (steam generator) response, a simple mathematical model of the steam generator under variable load conditions was proposed. In the proposed model, there are two dimensionless parameters and three constant coefficients. A linear relation between these dimensionless parameters was obtained. The correctness of the model was verified against the data obtained with a steam generator simulator for European Pressured Reactor and AP-600 reactors. A good agreement between the proposed model and the simulator data was achieved.
Źródło:
Archives of Thermodynamics; 2013, 34, 3; 75-88
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adress for Professor Krzysztof Jan Jesionek Anniversary
Autorzy:
Lewandowski, J.
Gnutek, Z.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175358.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam and gas turbine
power boiler
compressors
fluid-flow machinery
power plants
Opis:
This article presents professional activity of Krzysztof Jesionek within the background of his personal career in the field of heat and power engineering on Wrocław University of Technology. In particular, we present stages of scientific and professional development with an emphasis on nature Professor Jesionek’s career main driving forces as a result of his cooperation with industry and power engineering.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2014, 126; 3-20
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of stress and strain in specimens with rectangular cross-section subjected to torsion and bending with torsion
Autorzy:
Faszynka, S.
Lewandowski, J.
Rozumek, D.
Powiązania:
https://bibliotekanauki.pl/articles/386781.pdf
Data publikacji:
2016
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
numerical method
fatigue crack growth
torsion
bending with torsion
metody numeryczne
pękanie zmęczeniowe
skręcanie
zginanie ze skręcaniem
Opis:
The paper presents an analysis of the state of stress and crack tip opening displacement (strain) in specimens with rectangular cross-section subjected to torsion and combined bending with torsion. The specimens were made of the EN AW-2017A aluminium alloy. The specimens had an external unilateral notch, which was 2 mm deep and its radius was 22.5 mm. The tests were performed at constant moment amplitude MT=MBT= 15.84 N.m and under stress ratio R= -1. The exemplary results of numerical computations being obtained by using the FRANC3D software were shown in the form of stress and crack tip opening displacement (CTOD) maps. The paper presents the differences of fatigue cracks growth under torsion and bending with torsion being derived by using the FRANC3D software.
Źródło:
Acta Mechanica et Automatica; 2016, 10, 1; 5-11
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multifunctional, Optical Sensor for Analysis of Dynamic Pupillary Light Reflex
Autorzy:
Różanowski, K.
Lewandowski, J.
Murawski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1398782.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.66.Ct
42.30.Va
07.05.Pj
07.07.Df
Opis:
The aim of the publication is to describe the multifunctional optical sensor for analysis of dynamic pupillary light reflex developed by the authors which could be used as an objective indicator of human fatigue. The authors utilized knowledge gained from past experimental studies to develop a sensor, which along with custom software for detection of parameters of dynamic pupillary reflex provides a quick analysis of the human psychophysiological condition. Furthermore, the obtained parameters may also be utilized for medical purposes. The authors present the results of pilot studies prior to the development process of the sensory solution. The obtained result show that the type of light stimulation of the retina has a significant impact on the dynamic parameters of the pupillary reflex. The results played also an important role in shaping the structural assumptions of the sensor, so that it can serve as an indicator of the human fatigue level. The article includes results of experimental research conducted during the testing process of the sensor using various parameters of frequency light excitations, luminance and chrominance.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 723-729
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic analysis of biofuels as fuels for high temperature fuel cells
Autorzy:
Milewski, J.
Bujalski, W.
Lewandowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/240906.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biopaliwa
modelowanie matematyczne
ogniwo węglanowe
tlenkowe ogniwa paliwowe
biofuels
mathematical modeling
Molten carbonate fuel cell
solid oxide fuel cell
Opis:
Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.
Źródło:
Archives of Thermodynamics; 2012, 33, 4; 41-65
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the orientation of an object within a 3D space. Implementation and example applications
Autorzy:
Różanowski, K.
Lewandowski, J.
Placha, M.
Powiązania:
https://bibliotekanauki.pl/articles/397887.pdf
Data publikacji:
2015
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
AHRS
biomedical electronics
IMU
motion capture
spatial orientation
elektronika biomedyczna
orientacja przestrzenna
Opis:
The article presents a design of a measurement system implementing algorithms for determination of the orientation of objects within three-dimensional space using am integrated triaxial MEMS system, magnetometer, and Madgwick’s AHRS sensor fusion algorithm. Also included in the proposed implementation are the algorithms for calibration of sensors. Estimated orientation of the object of interest is provided using Euler’s angles or quaternions The system consists of a data acquisition system and software to visualize the acquired data. The main components of the acquisition system include a microcontroller featuring ARM Cortex M4 processor core and integrated 9DOF module consisting of an accelerometer, gyroscope, and magnetometer. The measurement system is capable of communicating with other devices via a Bluetooth interface. The measurements of the monitored values read by 9DOF sensors may be collected at sampling frequencies of up to 100Hz. Options to save data to SD cards and to maintain power supply from a battery are also available. The proposed solution is characterized by low construction costs, small dimensions, and ease of implementation in all types of systems. It can be used for example in mapping the movement of limbs (spatial orientation of the foot, detection of gait cycle phases, assessment of motor activity), as a support tool in inertial navigation systems or in the control of objects in motion (aerial vessels, mechanical vehicles). The article also presents an application of the system as a limb motion capture device.
Źródło:
International Journal of Microelectronics and Computer Science; 2015, 6, 4; 124-129
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and functional relationship of mammalian and nematode ferritins
Autorzy:
Lewandowski, J.
Komur, A.A.
Sobanska, D.
Powiązania:
https://bibliotekanauki.pl/articles/2096865.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nematode ferritins
FTH1
Caenorhabditis elegans
Opis:
Ferritin is a unique buffering protein in iron metabolism. By storing or releasing iron in a tightly controlled manner, it prevents the negative effects of free ferrous ions on biomolecules in all domains of life – from bacteria to mammals. This review focuses on the structural features and activity of the ferritin protein family with an emphasis on nematode ferritins and the similarities in their biological roles with mammalian ferritins. The conservative characteristic of the ferritin family across the species originates from the ferroxidase activity against redox-active iron. The antioxidative function of these proteins translates into their involvement in a wide range of important biological processes, e.g., aging, fat metabolism, immunity, anticancer activity, and antipathogenic activity. Moreover, disturbances in ferritin expression lead to severe iron-associated diseases. Research on the Caenorhabditis elegans model organism may allow us to better understand the wide spectrum of mechanisms involving ferritin activity.
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2021, 102, 4; 457-471
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stationary Properties of Superconducting Interferometers
Autorzy:
Lewandowski, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/1892080.pdf
Data publikacji:
1991-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.50.+r
85.25.Dq
Opis:
A generalized superconducting interferometer, comprising a parallel arrangement of (lumped) inductances and series (lumped) Josephson junctions is considered. Such a system can be seen as the building block of a simplified model of a high-T$\text{}_{c}$ superconductor with its haphazard distribution of Josephson weak links on grain boundaries and lattice defects. It is shown that the system properties can be self-consistently derived from a properly defined potential energy function, taking account of the energies of the system, its current source and external magnetic field. In particular, by solving a stationary problem for this function relative to conditions of constant current bias and constant magnetic flux applied to the system, the critical current of the interferometer can be determined in function of the applied flux. Stationary phase relations and their impact on other system variables are discussed in detail. The theory is applied to the simplest possible system exhibiting all discussed properties, i.e. an interferometer composed of two junctions in series and one junction in parallel.
Źródło:
Acta Physica Polonica A; 1991, 80, 6; 841-856
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System of biomedical signal measurement for psychological profiling of soldiers
Autorzy:
Różanowski, K.
Lewandowski, J.
Kleczkowski, J.
Sondej, T.
Powiązania:
https://bibliotekanauki.pl/articles/398061.pdf
Data publikacji:
2015
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
ASIC
biomedical electronics
health-chip
psychological profiles
elektronika biomedyczna
chip zdrowia
profile psychologiczne
Opis:
We present a project of a system of biological signal measurement for psychological profiling of soldiers. The system consists of specialized modules divided into measurement, communications, and powering blocks. The individual devices of the system communicate with one another thorough a dedicated protocol based on the CAN bus interface. The measurement system was designed as a portable, battery-powered device that could be attached to clothing. Apart from hardware, the system comprises a number of desktop and server applications. For data processing and storage, a number of dedicated applications were designed ranging from server applications to mobile user applications. In the article, we review mechanisms that employ genetic algorithms for a determination of the set of traits of an optimal psychological profile. Moreover, we describe ways of remote transmission of information to data bases with the use of the GPRS system. The presented system is designed as a specialized SOC integrated circuit.
Źródło:
International Journal of Microelectronics and Computer Science; 2015, 6, 4; 148-151
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Dimensional Behavior of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{x}$ Films on SrTiO$\text{}_{3}$ Substrates
Autorzy:
Mikheenko, P. N.
Lewandowski, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/1964342.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.62.Dh
74.76.-w
74.80.-g
74.80.Dm
Opis:
Long-term (up to 18 months) degradation of textured YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{x}$ films prepared by laser ablation and magnetron sputtering on single crystal SrΤiO$\text{}_{3}$, MgO and Al$\text{}_{2}$O$\text{}_{3}$ substrates were investigated. All films at each stage of exposition displayed a clearly visible quasi-2D behavior. From the measurements of the Kosterlitz-Thouless temperature it could be concluded that the oxygen content and density of charge carriers remained constant. It follows that the main consequence of degradation is the omission of some planes from the transport of supercurrent and the samples could be described in the model of layered structure with variable number of conducting planes. Using this model we find that effective thickness of an isolated CuO$\text{}_{2}$ plane in samples with greatest internal damage is ≈2Å.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 152-156
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of the Josephson Multi-Junction Systems with Junctions Characterized by Non-Sinusoidal Current - Phase Relationship
Autorzy:
Abal'osheva, I. S.
Lewandowski, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/2041445.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.50.+r
85.25.Am
85.25.Dq
Opis:
It is shown that the inclusion of junctions characterized by non-sinusoidal current - phase relationship in the systems composed of multiple Josephson junctions - results in the appearance of additional system phase states. Numerical simulations and stability considerations confirm that these phase states can be realized in practice. Moreover, spontaneous formation of the grain boundary junctions in high-T$\text{}_{c}$ superconductors with non-trivial current-phase relations due to the d-wave symmetry of the order parameter is probable. Switching between the phase states of multiple grain boundary junction systems can lead to additional 1/f noise in high-T$\text{}_{c}$ superconductors.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 687-691
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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