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Tytuł:
A simple method of determination of the degree of gas mixing by numerical Laplace inversion and Maple®
Autorzy:
Wójcik, M.
Szukiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/200207.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inverse boundary value problem
Gaver-Stehfest algorithm
axial gas dispersion coefficient
Peclet number
CAS program
algorytm Gavera-Stehfesta
dyspersja gazu
liczba Pecleta
program CAS
Maple
Opis:
This article presents a new efficient method of determining values of gas flow parameters (e.g. axial dispersion coefficient, DL and Pèclet number, Pe). A simple and very fast technique based on the pulse tracer response is proposed. It is a method which combines the benefits of a transfer function, numerical inversion of the Laplace transform and optimization allows estimation of missing coefficients. The study focuses on the simplicity and flexibility of the method. Calculations were performed with the use of the CAS-type program (Maple®). The correctness of the results obtained is confirmed by good agreement between the theory and experimental data for different pressures and temperature. The CAS-type program is very helpful both for mathematical manipulations as a symbolic computing environment (mathematical formulas of Laplace-domain model are rather sophisticated) and for numerical calculations. The method of investigations of gas flow motion is original. The method is competitive with earlier methods.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 2; 235-240
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical modelling of gas flow and determination of axial gas dispersion coefficients using numerical inverse laplace transform and maple in a typical commercial apparatus
Autorzy:
Wójcik, M.
Szukiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/185793.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical inversion of the Laplace transform
mathematical modelling
axial gas dispersion coefficient
Maple
numeryczna inwersja transformaty Laplaca
modelowanie matematyczne
osiowy współczynnik dyspersji gazu
Opis:
In this paper, a new simple method for determination of flow parameters, axial dispersion coefficients DL and Péclet numbers Pe was presented. This method is based on an accurate measurement model considering pulse tracer response. Our method makes it possible to test the character of gas flow motion and precisely measure flow parameters for different pressures and temperatures. The idea of combining the transfer function, numerical inversion of the Laplace transform and optimisation method gives many benefits like a simple and effective way of finding solution of inverse problem and model coefficients. The calculated values of flow parameters (DL and/or Pe) suggest that in the considered case the gas flow is neither plug flow nor perfect mixing under operation condition. The obtained outcomes agree with the gas flow theory. Calculations were performed using the CAS program type, Maple.
Źródło:
Chemical and Process Engineering; 2018, 39, 2; 223--232
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmiany w strukturze użytków rolnychw powiecie grójeckim po 1990 r.
Changes in the Structure of Agricultural Lands in Grójec County after 1990
Autorzy:
Wójcik, M.
Traczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/2031600.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
użytki rolne
sady
obszary wiejskie
agricultural lands
orchards
rural areas
Opis:
Celem opracowania jest określenie kierunków zmian w strukturze użytków rolnych w powiecie grójeckim w latach 1990-2010. Zmiany w powierzchni i strukturze użytków rolnych przeanalizowano na podstawie wyników Powszechnych Spisów Rolnych przeprowadzonych w 1996 oraz 2010 r. Analizy zmian w rozmieszczeniu sadów i gruntów ornych dokonano na podstawie mapy pokrycia terenu opracowanej przez Europejską Agencję Środowiska (Corine Land Cover).
The aim of the study is to determine changes in the structure of agricultural land in Grójec county and the direction of these changes in 1990-2010. The structure of agricultural land in Grójec county in the analysed period underwent heavy transformation. One factor that played a significant role in the this transformation was the change in economic conditions that followed Polish accession to the European Union. The accession made it necessary to adapt farms to operate in the new economic conditions. One of the conditions necessary to achieve good economic results and maintain profitability of production was specialisation. Even before Poland joined the EU, Grójec county was an area specialised in fruit picking, with orchards occupying 36% of the structure of agricultural land at the time. After Poland joined the EU, the area occupied by orchards started steadily growing, reaching 69% of all agricultural lands in the regions by 2010. The increase in the level of farm specialisation in fruit picking increased the area occupied by orchards, thus causing transformations in the structure of agricultural lands. As a result of the development of fruit picking, the area occupied by other types of agricultural production was limited. The area of arable lands decreased by 26%, meadows and pastures by 5%, while fallows and idle lands – by 2%. Some undeveloped lands not occupied by orchards has been dedicated to the cultivation of fruit trees and shrubs, or the construction of infrastructure related to fruit picking.
Źródło:
Biuletyn Komitetu Przestrzennego Zagospodarowania Kraju PAN; 2016, 262; 20-34
0079-3493
Pojawia się w:
Biuletyn Komitetu Przestrzennego Zagospodarowania Kraju PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Identification of the Material Hardening Parameters for Cyclic Loading - Experimental and Numerical Studies
Autorzy:
Skrzat, A.
Wójcik, M.
Powiązania:
https://bibliotekanauki.pl/articles/351789.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ratchetting
cyclic plasticity
non-symmetrical stress load
finite element method
Opis:
This paper presents the results of experimental studies and numerical simulations of the ratcheting for the PA6 aluminum. In the initial determination of the material hardening parameters, the samples were subjected to the symmetrical strain-controlled cyclic tension-compression test. The experimental stress-strain curve was compared with the numerical one obtained for non-linear Frederick-Armstrong and Voce models. For better fitting of both curves, the optimization procedure based on the least-square method and the fuzzy logic was applied. After establishing the hardening parameters, numerical simulations of the ratcheting were made. The boundary value problem was solved by means of discrete analysis. The data (force and displacement) obtained in numerical computations were used to control the ratchetting experiment. The results of experiments and numerical calculations were compared. Good convergence proves the reliability of the determination of material hardening data.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 779-786
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Społeczne i przestrzenne aspekty procesu odnowy wsi (przypadek województwa łódzkiego)
Social and spatial aspects of the rural renewal processes case of the łódzkie voivodeship
Autorzy:
Jeziorska-Biel, P.
Wójcik, M.
Powiązania:
https://bibliotekanauki.pl/articles/2031824.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
European funds
Łódzkie Voivodeship
rural renewal
social actions
Opis:
The key aim of this article is to define the socio-spatial aspects of implementing Rural Renewal Program in the Łódzkie Voivodeship. The authors analyze the temporal perspective of the first financial founds that came to Poland for the rural renewal, trying to find out the regularities and determinants of the processes. The rural renewal is a multifaceted term, and very difficult to operational. In the discusse of the spatial dimension of this process, the authors focus first on: the attempt to assess the changes in space initiated by the revitalizing actions in rural areas, and, second, the presentation of the spatial allocation of active communes in the Łódzkie Voivodeship. By characterizing the social aspect of rural renewal, the authors focus primarily on the impact of this process on the local community. The conclusions were formulated on the basis of the research carried out: qualitative analysis of the key program documents concerning the Sectoral Operational Program „Restructuring and  modernization of the food sector and rural development, 2004-2006“.
Źródło:
Biuletyn Komitetu Przestrzennego Zagospodarowania Kraju PAN; 2017, 267; 121-131
0079-3493
Pojawia się w:
Biuletyn Komitetu Przestrzennego Zagospodarowania Kraju PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kształtowanie tożsamości lokalnej w „tematycznej” odnowie wsi
Formation the local identity in the “thematic” Rural Renewa
Autorzy:
Wójcik, M.
Jeziorska-Biel, P.
Powiązania:
https://bibliotekanauki.pl/articles/2032281.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
odnowa wsi
wiejska przestrzeń tematyczna
tożsamość lokalna
rural renewal program
rural thematic space
local identity
Opis:
Artykuł ma na celu określenie głównych uwarunkowań rozwoju wiejskich przestrzeni tematycznych w kontekście odnowy wsi. Na tym tle autorzy podejmują próbę wyjaśnienia mechanizmów rządzących omawianym procesem oraz ich efektów. Wobec powyższego skoncentrowano się na przedstawieniu mechanizmów rozwoju procesów, które prowadzą do rozkwitu tej idei (anatomia sukcesu – przypadek wsi Sierakowo Sławieńskie), oraz takich, które ten rozwój spowalniają lub zupełnie ograniczają (anatomia porażki – przypadek wsi Lubcza).
The article aims to determine the main conditions for the development of rural thematic areas in the context of Rural Renewal. Against this background, the authors attempt to explain the mechanisms governing the discussed process and their effects. In view of the above, the focus was on presenting mechanisms for the development of processes that lead to the flowering of this idea (an anatomy of success – the case of the village of Sierakowo Sławieńskie) and those that slow down or completely limit this development (anatomy of failure – the case of the village of Lubcza).
Źródło:
Biuletyn Komitetu Przestrzennego Zagospodarowania Kraju PAN; 2018, 270; 174-189
0079-3493
Pojawia się w:
Biuletyn Komitetu Przestrzennego Zagospodarowania Kraju PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy Logic Enhancement of Material Strain Hardening Data Obtained in the Heyers Test
Autorzy:
Skrzat, A.
Wójcik, M.
Bąk, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/354901.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fuzzy logic
plasticity
material hardening parameters
Heyer's method
Opis:
Fuzzy logic determination of the material hardening parameters based on the Heyer’s method was applied in this research. As the fuzzy input variables, the length of two measuring bases and the maximum force registered in the Heyer's test were used. Firstly, the numerical experiment (the simulation of the fuzzification of the input data) with the assumed disturbance of input variables was performed. Next, on the basis of experimental investigations (eleven samples made from the same material), the membership functions associated with the input data were created. After that, the fuzzy analysis was examined. Fuzzy material hardening constants obtained by means of the α-level optimization and the extension principle methods were compared. Discrete values of the hardening data are found in the defuzzification process, by application of the mass center method.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 1059-1065
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the level of non-enzymatic antioxidants in leaves of Phaseolus coccineus (L.) plants under heavy metal stress
Autorzy:
Patrzylas, P.
Wojcik, M.
Skorzynska-Polit, E.
Powiązania:
https://bibliotekanauki.pl/articles/951290.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
non-enzymatic antioxidant
leaf
Phaseolus coccineus
reactive oxygen species
glutathione
cellular homeostasis
stress condition
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:
Measurement techniques used for analysis of the geometric structure of machined surfaces
Autorzy:
Niemczewska-Wójcik, M.
Mathia, T.
Wójcik, A.
Powiązania:
https://bibliotekanauki.pl/articles/406956.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface metrology
measurement techniques
SGS analysis
Opis:
The quality of machined surfaces, resulting from the manufacturing process and conditioning their functionality, is determined by the surface geometric structure (SGS). There is a close relationship between surface properties, shape, qualitative imagining of the surface topography, technique and technology employed for machining purposes [1, 2]. If a given surface is to have practical applications in engineering, the correct technological process needs to be chosen. In the paper, various techniques used for measuring the surface geometric structure were described. The results of the study, which were obtained from different measuring devices like Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Optical Interferometer (WLI), were presented. Optical Microscopy (OM) was shown as a helpful device to analyse some aspects of surface topography. Each measuring technique provided different, yet complementary data on the topography of the machined surfaces. Owing to this, a full characterization of the geometric surface structure of the machined surfaces was enabled, including surface properties resulting from the applied technological process. Based on the measurements made, the characteristics of chosen devices (measurement techniques) were defined with an indication of how they can be applied to the analysis of the surface geometric structure (SGS). The devices which are considered to give the best view of examined surfaces and allow a thorough analysis of their irregularities were then indicated.
Źródło:
Management and Production Engineering Review; 2014, 5, 2; 27-32
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Free-Form Surfaces’ Reconstruction Accuracy
Autorzy:
Wójcik, A.
Niemczewska-Wójcik, M.
Sładek, J.
Powiązania:
https://bibliotekanauki.pl/articles/220773.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reverse engineering
accuracy assessment
free-form surface
coordinate measuring machine
radius correction
Opis:
The paper presents the problem of assessing the accuracy of reconstructing free-form surfaces in the CMM/CAD/CAM/CNC systems. The system structure comprises a coordinate measuring machine (CMM) PMM 12106 equipped with a contact scanning probe, a 3-axis Arrow 500 Vertical Machining Center, QUINDOS software and Catia software. For the purpose of surface digitalization, a radius correction algorithm was developed. The surface reconstructing errors for the presented system were assessed and analysed with respect to offset points. The accuracy assessment exhibit error values in the reconstruction of a free-form surface in a range of ± 0.02 mm, which, as it is shown by the analysis, result from a systematic error.
Źródło:
Metrology and Measurement Systems; 2017, 24, 2; 303-312
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Precision machining of spherical ceramic parts
Precyzyjna obróbka ceramicznych elementów kulistych
Autorzy:
Gawlik, J.
Krajewska, J.
Niemczewska-Wójcik, M.
Powiązania:
https://bibliotekanauki.pl/articles/175636.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zirconium
sapphire
precision machining
surface geometric structure
cyrkon
szafir
obróbka precyzyjna
struktura geometryczna powierzchni
Opis:
Physical and mechanical properties of ceramic materials make them useful applications in both mechanical and medical engineering. This paper presents the technological system for precision machining of super hard ceramic materials. As an example of precisely processed ceramic components a circular / spherical element can be given, which was used in an endoprosthesis hip replacement. This paper presents selected characteristics of geometrical surface structure after precision machining and finishing and indicates directions for further research into the development of the technological qualities of ceramic components.
Materiały ceramiczne charakteryzują się właściwościami fizycznymi i mechanicznymi determinującymi ich zastosowanie zarówno w budowie maszyn, jak również w medycynie. W pracy przedstawiono system technologiczny do precyzyjnej obróbki trudnoobrabialnych materiałów ceramicznych. Podano przykłady elementów kulistych do zastosowania na endoprotezy stawu biodrowego. Określono wybrane charakterystyki struktury geometrycznej ich powierzchni po obróbce kształtującej i wykończeniowej. Wskazano kierunki dalszych badań z zakresu kształtowania jakości technologicznej elementów z materiałów ceramicznych.
Źródło:
Advances in Manufacturing Science and Technology; 2013, 37, 4; 19-30
0137-4478
Pojawia się w:
Advances in Manufacturing Science and Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proliferative and oxidative response of hepatocytes (Hep) and hepatic stellate cells (HSC) isolated from rats exposed to ketogenic diet
Autorzy:
Wojcik, M.
Wessely-Szponder, J.
Kosior-Korzecka, U.
Powiązania:
https://bibliotekanauki.pl/articles/30839.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Ketogenic diet (KD) is considered in the context of its anti-epileptic effects, but its influence on liver dysfunction has not been elucidated yet. The study was aimed to investigate the activity of hepatocytes (Hep) and hepatic stellate cells (HSC) isolated from rats fed with KD, in respect of NO and superoxide generation by these cells as well as their proliferative activity in vitro. We also sought to characterize the plasma FFA profiles in control and ketogenic rats. Hep and HSC were isolated by the collagenase perfusion method and separated by the Percoll gradient centrifugation. After the 4th, 8th and 12th day of incubation, the media were collected for further analysis. NO generation increased within the time of incubation both in Hep and HSC isolated from KD-rats. In HSC group NO production raised significantly from 2.65 ± 0.07 μM/10⁶ cells on 4th day of incubation to 5.49 ± 1.2 μM/10⁶ cells on 12th day of incubation. In respect to O₂-. generation experimental Hep and HSC provide considerably higher quantities of this free radical. until 12th day of incubation (2.5 ± 0.07 and 3.2 ± 0.3 nM/10⁶ cells, respectively). Although KD exerts anti-proliferative effect on hepatocytes, in respect to HSC it intensifies their proliferative activity. Furthermore, as we estimated on the basis of NO and O₂-. generation both Hep and HSC exposed to KD are the source of free radicals.
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:
The in vitro effect of bovine lactoferrin on the activity of organ leukocytes in rainbow trout [Oncorhynchus mykiss], European eel [Anguilla anguilla] and wels catfish [Silurus glanis]
Autorzy:
Malaczewska, J
Wojcik, M.
Wojcik, R.
Siwicki, A.K.
Powiązania:
https://bibliotekanauki.pl/articles/30969.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fish
rainbow trout
Oncorhynchus mykiss
European eel
Anguilla anguilla
catfish
Silurus glanis
in vitro effect
bovine lactoferrin
lactoferrin
leucocyte
freshwater fish
Opis:
Lactoferrin (LF) is a glycoprotein found in milk, neutrophil granules, secretions and selected organs of mammals. Lactoferrin exhibits antibacterial, antiviral, fungicidal, immunoregulatory and other functions. Although fish are devoid of this protein and its cell receptors, LF effect on the immune mechanisms of fish has been demonstrated. The objective of this study was to investigate the effect of bovine lactoferrin, applied in vitro, on the activity of head kidney and spleen leukocytes in three freshwater fish species: rainbow trout (Oncorhynchus mykiss), European eel (Anguilla anguilla) and weis catfish (Silurus glanis). The obtained results validate LF beneficial effect on the respiratory burst of phagocytes in rainbow trout and weis catfish despite the fact that the potential killing activity against Aeromonas hydrophila was not stimulated in any of the studied species. Bovine lactoferrin enhanced the proliferation of T-lymphocytes in rainbow trout and European eel, as well as of B-lymphocytes in rainbow trout.
Źródło:
Polish Journal of Veterinary Sciences; 2010, 13, 1; 83-88
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Product quality assessment – measurement and analysis of surface topography
Autorzy:
Niemczewska-Wójcik, M.
Sładek, J.
Tabaka, M.
Wójcik, A.
Powiązania:
https://bibliotekanauki.pl/articles/220537.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface metrology
topography
measurement devices
analysis of defects
quality
Opis:
This paper concerns the issues of measurement techniques, analysis and assessment of the machined surface geometric structure. The aim of this work was to show the application of surface analysis in diagnosing the causes of discrepancies occurring in the manufacturing process, which may result from ill-matched (poorly fitting) process parameters. An appropriate system of control and interpretation of results may allow early reaction to unfavorable trends (for example blunting of the tool) and prevention of undesirable defects. The subject of research was a waste basket used in the construction of retaining sewer systems. In this paper, the quality of the waste basket as well as its manufacturing process were analyzed and assessed. The research was carried out with the use of three measurement stands, i.e. optical microscopy (OM), scanning electron microscopy (SEM) and white light interferometer (WLI). The surface analysis proved to be important from the viewpoint of outlining the production process as well as improving the product quality. The software used for topographical analysis appeared to be significant for the success of the analysis, providing notable economic effects, namely the lack of defects.
Źródło:
Metrology and Measurement Systems; 2014, 21, 2; 271-280
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of salicylic acid and excess of copper on selected stress parameters induced in Phaseolus coccineus leaves
Autorzy:
Hanaka, A.
Dresler, S.
Bednarek, W.
Wojcik, M.
Maksymiec, W.
Powiązania:
https://bibliotekanauki.pl/articles/81194.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
salicylic acid
copper excess
phenolic compound
abiotic stress
anthocyanin
Phaseolus coccineus
runner bean plant
leaf
stress parameter
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
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