Skocz do pozycji: 1.

Tytuł:

Some remarks on positron/positronium diffusion models

Autorzy:

Świątkowski, W.

Powiązania:

https://bibliotekanauki.pl/articles/148428.pdf

Data publikacji:

2003

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

diffusion
diffusion length
positron
positronium

Opis:

Positrons thermalized near the sample boundary (as well as Ps atoms formed in the sample) can reach the boundary as a result of diffusive movement. Observations of such effects as positron reemission or positron surface trapping as well as positronium emission allow one to calculate respective diffusion lengths. From the presented analysis it follows that some models used in such calculations give quite wrong results.

Źródło:

Nukleonika; 2003, 48, 3; 141-144
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 2.

Tytuł:

Diffusion Path in Ternary One-Phase Systems: An Overview

Autorzy:

Serafin, D.
Nowak, W. J.
Wierzba, P.
Wędrychowicz, S.
Wierzba, Bartek

Powiązania:

https://bibliotekanauki.pl/articles/175705.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

inter-diffusion
up-hill diffusion
diffusion path

Opis:

In this article, the fundamental questions concerning the diffusion path, in particular, what is the shape of diffusion path in ternary systems and how to approximate it from the initial concentration profile, will be answered. The new rules were found which allow for determining the diffusion path from a known initial concentration of the components. This approximation will allow for designing new materials without a time-consuming numerical simulation of the full system of equations. It is shown that the difference in intrinsic diffusion coefficients determines the up-hill diffusion.

Źródło:

Advances in Manufacturing Science and Technology; 2020, 44, 1; 1-8
0137-4478

Pojawia się w:

Advances in Manufacturing Science and Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 3.

Tytuł:

Reaction-diffusion coupled inclusions with variable exponents and large diffusion

Autorzy:

Simsen, Jacson
Stefanello Simsen, Mariza
Wittbold, Petra

Powiązania:

https://bibliotekanauki.pl/articles/2052022.pdf

Data publikacji:

2021

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

reaction-diffusion coupled systems
variable exponents
attractors
upper semicontinuity
large diffusion

Opis:

This work concerns the study of asymptotic behavior of coupled systems of p(x)-Laplacian differential inclusions. We obtain that the generalized semiflow generated by the coupled system has a global attractor, we prove continuity of the solutions with respect to initial conditions and a triple of parameters and we prove upper semicontinuity of a family of global attractors for reaction-diffusion systems with spatially variable exponents when the exponents go to constants greater than 2 in the topology of [formula] and the diffusion coefficients go to infinity.

Źródło:

Opuscula Mathematica; 2021, 41, 4; 539-570
1232-9274
2300-6919

Pojawia się w:

Opuscula Mathematica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

Strangely sweeping one-dimensional diffusion

Autorzy:

Rudnicki, Ryszard

Powiązania:

https://bibliotekanauki.pl/articles/1311888.pdf

Data publikacji:

1993

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

diffusion process
parabolic equation

Opis:

Let X(t) be a diffusion process satisfying the stochastic differential equation dX(t) = a(X(t))dW(t) + b(X(t))dt. We analyse the asymptotic behaviour of p(t) = Prob{X(t) ≥ 0} as t → ∞ and construct an equation such that $lim sup_{t→∞} t^{-1} ∫_0^t p(s) ds = 1$ and $lim inf_{t→∞}t^{-1} ∫_0^t p(s) ds = 0$.

Źródło:

Annales Polonici Mathematici; 1993, 58, 1; 37-45
0066-2216

Pojawia się w:

Annales Polonici Mathematici

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

Diffusion in Networks

Autorzy:

Kasprzak, R.

Powiązania:

https://bibliotekanauki.pl/articles/309179.pdf

Data publikacji:

2012

Wydawca:

Instytut Łączności - Państwowy Instytut Badawczy

Tematy:

complex network
diffusion
probabilistic finitestate machine

Opis:

In this paper a concept of method and its application examining a dynamic of diffusion processes in networks is considered. Presented method was used as a core framework for system CARE (Creative Application to Remedy Epidemics).

Źródło:

Journal of Telecommunications and Information Technology; 2012, 2; 99-106
1509-4553
1899-8852

Pojawia się w:

Journal of Telecommunications and Information Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

Anomalous and traditional diffusion modelling in SOM learning

Autorzy:

Hrebik, Radek
Kukal, Jaromir

Powiązania:

https://bibliotekanauki.pl/articles/949793.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

self organization
Kohonen map
diffusion learning
anomalous diffusion
SOM

Opis:

The traditional self organizing map (SOM) is learned by Kohonen learning. The main disadvantage of this approach is in epoch based learning when the radius and rate of learning are decreasing functions of epoch index. The aim of study is to demonstrate advantages of diffusive learning in single epoch learning and other cases for both traditional and anomalous diffusion models. We also discuss the differences between traditional and anomalous learning in models and in quality of obtained SOM. The anomalous diffusion model leads to less accurate SOM which is in accordance to biological assumptions of normal diffusive processes in living nervous system. But the traditional Kohonen learning has been overperformed by novel diffusive learning approaches.

Źródło:

Archives of Control Sciences; 2019, 29, 4; 699-717
1230-2384

Pojawia się w:

Archives of Control Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

Diffusion of lead ions trough the Poznan Clay (Neogene) and through glacial clay

Autorzy:

Mieszkowski, R.

Powiązania:

https://bibliotekanauki.pl/articles/2059620.pdf

Data publikacji:

2003

Wydawca:

Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy

Tematy:

apparent diffusion coefficient
diffusion in clays
Fick's Law

Opis:

Two main kinds of migration through clays can be distinguished: advection and diffusion. The main force for advective flow is the water pressure gradient, while ionic concentration gradients drive diffusion. In compacted clays the hydraulic permeability is very low, therefore the diffusion process predominates. Clays can be considered as waste repositories. This paper shows characteristics of the diffusion process and the application of this process to modelling of waste migration in clays. Additionally, a new calculation method for the apparent diffusion coefficient using the finite-difference method is given. Experimental, values of the apparent diffusion coefficient Dapp for Poznan Clay and glacial clay are respectively 2.2_2.6 _ 10-12 m2/s and 2.6_4.4 _ 10-12 m2/s.

Źródło:

Geological Quarterly; 2003, 47, 1; 111-118
1641-7291

Pojawia się w:

Geological Quarterly

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Asymptotic dissipativity of the diffusion process in the asymptotic small diffusion scheme

Autorzy:

Kinash, A.
Chabanyuk, Y.
Khimka, U.

Powiązania:

https://bibliotekanauki.pl/articles/122512.pdf

Data publikacji:

2015

Wydawca:

Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej

Tematy:

small series parameter
diffusion
asymptotic dissipativity

Opis:

This paper considers the random evolution with Markov switching. The resulting limited process is diffusion and depends on the small series parameter. The sufficient conditions of dissipativity of the limited process were obtained. Since the conditions of the Model Limit theorem and dissipativity conditions were set asymptotic dissipativity of the output process.

Źródło:

Journal of Applied Mathematics and Computational Mechanics; 2015, 14, 4; 93-103
2299-9965

Pojawia się w:

Journal of Applied Mathematics and Computational Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

Innovation Diffusion in the Supply Chain

Autorzy:

Laskowska-Rutkowska, A.

Powiązania:

https://bibliotekanauki.pl/articles/409597.pdf

Data publikacji:

2015

Wydawca:

Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej

Tematy:

innovation diffusion
model
supply chain

Opis:

Professional literature has not devoted too much attention to innovation diffusion in the supply chain. Specificity of innovation in supply chains also lacks relevant classification. The aim of this paper is to fill this gap by suggesting classification of innovation adjusted to specificity of supply chains and to describe the model of innovation diffusion in the supply chain. In order to verify the model of innovation diffusion in the supply chain, the following research methods were used: literature research, case description and instrumental case study. These are qualitative methods, often applied in theories of management. There were presented two instrumental descriptions of cases, being an effect of literature research and four descriptions of cases, being based on descriptions of innovative solutions in the logistics, submitted to the Polish contest titled "Innovative Solutions for the Logistics" in 2011. The research hypothesis, which is the model of innovation diffusion in the supply chain, has only been partly validated. As a result, the model of innovation diffusion in the supply chain requires further research, with the aim of the confirmation or the falsification.

Źródło:

Research in Logistics & Production; 2015, 5, 3; 287-297
2083-4942
2083-4950

Pojawia się w:

Research in Logistics & Production

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

Interface Diffusion Behavior of Co40Al-X (X = Ni, Cr, Ti) System by Diffusion Multiple

Autorzy:

Shang, Hang
Gao, Qiuzhi
Jiang, Yujiao
Ma, Qingshuang
Li, Huijun
Zhang, Hailian

Powiązania:

https://bibliotekanauki.pl/articles/2203747.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

Co-Al-X system
diffusion multiple
interface
diffusion
mechanical properties

Opis:

Diffusion multiple method was applied to investigate the alloying elements distribution and interface diffusion reactions in Co-Al-X system, in order to accelerate the alloy development. The diffusion regions of Co-Al-X system at 1173 K were investigated by scanning electron microscope (SEM) and nanoindentation. SEM images show that phases of Co-Al-Ni diffusion interface consisted of β-CoAl + γ Co, γ Co, γ + γ'-(Co, Ni)3Al and γ Ni, while Co-Al-Cr diffusion interface is shaped with δ + γ + β, γ and σ region. TiNiX diffusion layer with high Ni-content was formed in Co-Al-Ti diffusion interface. The diffusion layers during diffusion multiple play an important role in mechanical properties in these alloying systems. The γ + γ' diffusion layer in Co-Al-Ni diffusion interface presented the best comprehensive performance, while the highest hardness (17.48 GPa) was confirmed in Co-Al-Cr diffusion interface due to a large number of brittle phases. Darken method was applied to determine the interdiffusion coefficients of alloying elements in pseudo-binary phase, accordingly the diffusion capacities of alloying elements can be ordered as Al > Ni > Cr in Co-based alloys.

Źródło:

Archives of Metallurgy and Materials; 2023, 68, 1; 275--286
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

Singlet oxygen lifetime and diffusion measurements

Autorzy:

Ożog, Łukasz
Aebisher, David

Powiązania:

https://bibliotekanauki.pl/articles/454834.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego

Tematy:

photodynamic therapy
singlet oxygen
diffusion

Opis:

Introduction. Photodynamic therapy (PDT) is considered to be a promising antitumor methodology due the cytotoxicity of singlet oxygen (1 O2 ). Aim. To present singlet oxygen which is highly reactive and decomposes to the ground state rapidly. Material and methods. Analysis of literature. Results. This review presents techniques to measure lifetime and diffusion of 1 O2.

Źródło:

European Journal of Clinical and Experimental Medicine; 2018, 2; 123-126
2544-2406
2544-1361

Pojawia się w:

European Journal of Clinical and Experimental Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Alternative methodology to determine effective coefficient of methane diffusion in coal

Autorzy:

Koptoń, Henryk

Powiązania:

https://bibliotekanauki.pl/articles/1839042.pdf

Data publikacji:

2020

Wydawca:

Główny Instytut Górnictwa

Tematy:

mining
coal
sorption
diffusion
methane
diffusion coefficient
górnictwo
węgiel
sorpcja
dyfuzja
metan
współczynnik dyfuzji

Opis:

The article presents the results of research in to the development of an alternative method of determining the effective coefficient of methane diffusion in coal, based on a mathematical model following Fick's second law. The research was conducted based on the recorded courses of methane sorption kinetics in coal samples obtained in laboratory conditions with the precise gravimetric sorption system IGA-001. The value of the coefficient was treated as an element tuning the model in such a way that the average relative error of the ex post was as small as possible. Model verification indicated the correctness of its assumptions. The development of a more accurate methodology to determine the effective coefficient of methane diffusion in coal will enable the verification of the models applied in order to describe the physical and chemical mechanisms of the methane desorption natural phenomenon. It will also pave the way for further research aimed at the determination of: the gas bearing capacity of coal seams, the degree of degassing of seamswhich results from the mining operations being conducted; or to what extent it is possible to degas the deposits.

Źródło:

Journal of Sustainable Mining; 2020, 19, 2; 88-95
2300-1364
2300-3960

Pojawia się w:

Journal of Sustainable Mining

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

Analysis of the possibility of shaping the sound diffusion coefficient of diffusers based on acoustic metamaterials

Autorzy:

Rubacha, Jarosław

Powiązania:

https://bibliotekanauki.pl/articles/2202416.pdf

Data publikacji:

2022

Wydawca:

Politechnika Poznańska. Instytut Mechaniki Stosowanej

Tematy:

metamaterial
sound diffusion
diffusion coefficient
metamateriał
dyfuzja dźwięku
współczynnik dyfuzji

Opis:

The article presents the analysis of the possibilities of using acoustic metamaterial to build sound diffusers. The diffusers composed of slots loaded with a curved quarter-wave resonator were investigated. Such solutions induce dispersion and the slow sound effect to increase the effective depth of the quarter-wave resonator. The sound diffusion coefficient was calculated with the use of numerical models of diffusers. Next, obtained results were compared with the Schroeder diffuser. In conclusion, it was shown, that acoustic metamaterials affect the frequency band of the diffuser and the effectiveness of the obtained sound diffusers depend on relative width of slits.

Źródło:

Vibrations in Physical Systems; 2022, 33, 2; art. no. 2022210
0860-6897

Pojawia się w:

Vibrations in Physical Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Modelling of heat diffusion in composites

Autorzy:

Bondyra, A.

Powiązania:

https://bibliotekanauki.pl/articles/243729.pdf

Data publikacji:

2013

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

finite element method
glass reinforced composites
heat diffusion
fire

Opis:

Composites structures are widely using in varied fields of industry, where it has to take into account changes of temperature or it is possibility of fire hazards. Heat transfer and fire conditions in composites are very often analysis issues nowadays. A large amount of research in area of modelling heat transfer and fire loading of composites has been performed for both experimental studies and modelling and simulation. The most common areas of analysis of thermal composite structures are: multiscale modelling of heat transfer, simultaneous fire and mechanical loading, fire involved failure and temperature distribution under fire and elevated temperature conditions. This paper presents analysis of heat transfer in composites with taking into account their shape and thickness. The models include a convection mode of heat transfer. The first composite plate is 10 cm wide by 10 cm tall with a thickness of 1 cm. The modified structure has also second part, smaller plate on top 5 cm wide by 5 cm in right corner. They made of glass/vinylester composite. The plates are heating in one, two and three directions. The results are shown in forms of contours of temperature distribution and thermal gradient. Comparison of results for the modelled structures shows differences in the shape and thickness of the analysed structure.

Źródło:

Journal of KONES; 2013, 20, 3; 63-69
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Optimal Mass Diffusion Transfer in Solids Using Heat Transfer Similarities

Autorzy:

Jaber, Samar
Alahmer, Ali
Borowski, Gabriel
Alsaqoor, Sameh

Powiązania:

https://bibliotekanauki.pl/articles/957972.pdf

Data publikacji:

2019

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

diffusion transfer
Fick's Law
diffusion resistance
transfer dyfuzyjny
prawo Ficka
opór dyfuzyjny

Opis:

A new concept of solid-solid mass diffusion fin was introduced in this paper. The authors described the mass diffusion in fluid flows to analyze the transfer process in solids and its applications, especially in metallurgical research. Using the advantage of the similarity between heat transfer and mass diffusion transfer will make this issue more practical. The authors suggested a new approach to determine the maximum mass diffusion transfer between two solids by implementing of the extended surface on each solid, where the optimal mass diffusion between solids is required. Then, meshing the surfaces together in order to increase the transfer efficiency was carried out. A complete analysis of the extended surfaces design (diffusion fins), its efficiency and effectiveness were presented. Moreover, mathematical models of each consideration were constructed. The authors found that the total surface efficiency increased along with the number of mass diffusion fins attached to the base, but its effectiveness did not. The mass diffusion for an extended plate increased the total mass diffusion transfer between two materials.

Źródło:

Advances in Science and Technology. Research Journal; 2019, 13, 4; 54-59
2299-8624

Pojawia się w:

Advances in Science and Technology. Research Journal

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Mechanizmy dyfuzji wiedzy w regionie
The mechanisms of knowledge diffusion in the region

Autorzy:

Fic, Maria

Powiązania:

https://bibliotekanauki.pl/articles/534358.pdf

Data publikacji:

2011-12-15

Wydawca:

Uniwersytet Rzeszowski. Wydział Ekonomii

Tematy:

knowledge
diffusion
region

Opis:

The aim of the article is to present mechanisms of knowledge diffusion in the region. The authors discuss methods of aquisition of knowledge by agents functioning in the region, and channels of knowledge distribution - private persons' and public channels, institutional channels and channels based on information and communication systems. They show also the role of knowledge diffusion in the process of knowledge management in the region.

Źródło:

Przedsiębiorstwo i Region; 2011, 3; 16-23
2080-458X

Pojawia się w:

Przedsiębiorstwo i Region

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Diffusion weighted imaging in differentiation of the clear cell RCC from the major non-clear cell RCC subtypes

Autorzy:

Kış, Naciye
Erok, Berrin

Powiązania:

https://bibliotekanauki.pl/articles/2040173.pdf

Data publikacji:

2021-09-30

Wydawca:

Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego

Tematy:

apparent diffusion coefficient
diffusion weighted imaging
renal cell carcinoma

Opis:

Introduction. Renal cell carcinoma (RCC) is the most common malignant renal tumor in adults accounting for 80-90% of primary malignant adult renal neoplasms. RCC represents a very heterogenous groups of tumors with a number of distinct histological varieties, of which the major 3 subtypes are clear cell RCC (70-80%), papillary RCC (13-20%), and chromophobe RCC (5%). Imaging features are varied from solid and relatively homogenous appearance to markedly heterogenous appearance with cystic changes, hemorrhage and necrosis. The use of diffusion weighted imaging (DWI) for RCC subtyping and also for differentiation of high grade and low grade tumors has been showed to be useful in many studies in the literature. Aim. In this study, we aimed to determine the comparative contribution of DWI in differentiation of the clear cell RCC from the major non-clear cell RCC subtypes at standard high b-value (1000 s/mm2) versus low b-value (500 s/mm2). In addition, we also aimed to assess the diagnostic performance of DWI for differentiating high grade clear cell RCC from low grade clear cell RCC based on Fuhrman grades in our patients. Material and methods. 62 cases with a prediagnosis of RCC according to MRI findings including DWI sequence with histological verification and subtyping of renal cortical tumor following a total or partial nephrectomy were included in the study. Results. Among 62 cases, 46 were male and 16 were female, with mean age of 59.5±15.7. Pathological diagnoses of 62 cases were as follows, clear cell RCC, (44) papillary cell RCC (14) and chromophobe cell RCC (4). They were divided into two groups as clear cell RCC group (44 cases) and non-clear cell RCC group (18 cases). There was no statistically significant difference between the mean ADC values of clear cell and non-clear cell groups at b-value of 1000 s/mm2 (p>0.05). However, the mean ADC level for clear cell RCC group at b-value of 500 s/mm2 were significantly higher than for non-clear cell RCC group (p<0.05). When a value of 0.99x10-3 mm2/s was set as cut-off for ADC at b-factor of 500 s/mm2, differentiation was achieved with a high sensitivity (91%) and specificity (56%). Regarding the diagnostic performance of DWI for differentiating high from low Fuhrman grades clear cell RCCs, there was no statistically significant difference between the ADC values of Grade I-II clear cell RCC cases and Grade III-IV clear cell RCC cases at b-factor of 1000 s/mm2 (p>0.05). However, ADC values for grade III-IV group was statistically significantly lower than ADC values for Grade I-II group at b-factor of 500 s/mm2 level. Conclusion. ADC measurements at moderate b-value of 500 s/mm2 were more sensitive in subtyping and grading of RCC cases. This technique can be used in clinical practice as a fast and additional sequence in abdominal MRI.

Źródło:

European Journal of Clinical and Experimental Medicine; 2021, 3; 215-220
2544-2406
2544-1361

Pojawia się w:

European Journal of Clinical and Experimental Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Static and kinematic shakedown theorems in diffusion-induced plasticity

Autorzy:

Peigney, Michael

Powiązania:

https://bibliotekanauki.pl/articles/1839663.pdf

Data publikacji:

2020

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

plasticity
shakedown
diffusion-induced stress
lithium-ion batteries

Opis:

We present shakedown theorems applying to cyclically loaded media in which plastic flow and diffusion of guest atoms are coupled. The presented theorems are in the spirit of Melan and Koiter theorems in plasticity. They allow one to estimate the loading parameters for which elastic shakedown occurs, i.e. for which the plastic strain stabilizes to a time-independent limit. An application related to lithium-ion batteries is presented.

Źródło:

Journal of Theoretical and Applied Mechanics; 2020, 58, 2; 415-424
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

From Diffusion to Translation and Back. Disembedding–Re-embedding and Re-invention in Sociological Studies of Diffusion

Autorzy:

Mica, Adriana

Powiązania:

https://bibliotekanauki.pl/articles/1930004.pdf

Data publikacji:

2013-03-21

Wydawca:

Polskie Towarzystwo Socjologiczne

Tematy:

diffusion
translation
disembedding–re-embedding of ideas
re-invention of innovations
Scandinavian institutionalism

Opis:

This paper reviews and parallels the thesis of disembedding–re-embedding of ideas, objects and practices in the translation paradigm (à la Scandinavian institutionalism) with the discussion of reinvention in the diffusion of innovations theory (as put forward by Everett M. Rogers). The main inquiry to be answered is the extent to which these two propositions might be taken as theoretical allomorphs of a generic treatment of the dialectics of circulation of ideas. The analysis of the two assumptions makes use of Djelic’s (2008) classification of three main framing types within sociological studies of diffusion: diffusion as epidemiology, diffusion as encounter with embeddedness, and diffusion as mediation and construction. The main input of the article is that it shows that the re-invention hypothesis links the diffusion of innovations theory with the diffusion as encounter with embeddedness model, while the disembedding–re-embedding of ideas perspective associates the translation paradigm with the diffusion as mediation and construction model. The paper further discusses the dynamics as well as the theoretical implications of these theoretical affinities for the Scandinavian translation stream.

Źródło:

Polish Sociological Review; 2013, 181, 1; 3-20
1231-1413
2657-4276

Pojawia się w:

Polish Sociological Review

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Liquefaction of saturated soil and the diffusion equation

Autorzy:

Sawicki, A.
Sławińska, J.

Powiązania:

https://bibliotekanauki.pl/articles/178612.pdf

Data publikacji:

2015

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

liquefaction
diffusion equation
saturated soils
sea bed

Opis:

The paper deals with the diffusion equation for pore water pressures with the source term, which is widely promoted in the marine engineering literature. It is shown that such an equation cannot be derived in a consistent way from the mass balance and the Darcy law. The shortcomings of the artificial source term are pointed out, including inconsistencies with experimental data. It is concluded that liquefaction and the preceding process of pore pressure generation and the weakening of the soil skeleton should be described by constitutive equations within the well-known framework of applied mechanics. Relevant references are provided.

Źródło:

Studia Geotechnica et Mechanica; 2015, 37, 2; 39-44
0137-6365
2083-831X

Pojawia się w:

Studia Geotechnica et Mechanica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Contribution of diffusion weighted MRI to the differential diagnosis of renal masses

Autorzy:

Kış, Naciye
Gülden Düzkalır, Hanife
Oğuzhan Ağaçlı, Mehmet
Erok, Berrin
Gamze Kılıçoğlu, Zeynep

Powiązania:

https://bibliotekanauki.pl/articles/2049180.pdf

Data publikacji:

2022-03-30

Wydawca:

Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego

Tematy:

apparent diffusion coefficient
diffusion weighted imaging
renal neoplasms

Opis:

Introduction and aim. We aimed to assess the usefulness of diffusion weighted imaging (DWI) and apparent diffusion coefficients (ADCs) for characterizing renal masses. Material and methods. In this retrospective study we measured the ADC values of renal masses at b=0, b=500 and b=1000. Measurements were made by placing a circular region of interest with a diameter of 1 cm. ADC values from normal renal parenchyma were taken to define the ADC and to compare with the ADC values of the lesions. Results. A total of 72 lesions of 54 patients were included.40 of the masses were benign and 32 were malignant. The ADC values of benign lesions at both b values were significantly higher than malignant lesions. We found the lowest values in angiomyolipomas (AMLs) and oncocytomas and the highest values in Bosniac type I cysts. Similarities was found between the ADC values of some AMLs and the RCCs. In terms of statistical results, the inclusion of AMLs in the analysis did not significantly affect the difference between malignant and benign lesions. Conclusion. In our study, the ADC values of benign renal masses were higher than those of normal renal parenchyme, which is higher than those of malignant renal masses.The lowest ADC values were observed in AMLs and oncocytomas.

Źródło:

European Journal of Clinical and Experimental Medicine; 2022, 1; 44-48
2544-2406
2544-1361

Pojawia się w:

European Journal of Clinical and Experimental Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Impact of Values of Diffusion Coefficient on Results of Diffusion Modelling Driven by Chemical Potential Gradien

Autorzy:

Wróbel, Marek
Burbelko, Andriy

Powiązania:

https://bibliotekanauki.pl/articles/2174626.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

foundry industry
application of information technology
diffusion modelling
Calphad method
chemical potential
diffusion coefficient
przemysł odlewniczy
zastosowanie technologii informatycznej
modelowanie dyfuzyjne
metoda Calphad
potencjał chemiczny
współczynnik dyfuzji

Opis:

In the paper critical role of including the right material parameters, as input values for computer modelling, is stressed. The presented model of diffusion, based on chemical potential gradient, in order to perform calculations, requires a parameter called mobility, which can be calculated using the diffusion coefficient. When analysing the diffusion problem, it is a common practice to assume the diffusion coefficient to be a constant within the range of temperature and chemical composition considered. By doing so the calculations are considerably simplified at the cost of the accuracy of the results. In order to make a reasoned decision, whether this simplification is desirable for particular systems and conditions, its impact on the accuracy of calculations needs to be assessed. The paper presents such evaluation by comparing results of modelling with a constant value of diffusion coefficient to results where the dependency of Di on temperature, chemical composition or both are added. The results show how a given deviation of diffusivity is correlated with the change in the final results. Simulations were performed in a single dimension for the FCC phase in Fe-C, Fe-Si and Fe-Mn systems. Different initial compositions and temperature profiles were used.

Źródło:

Archives of Foundry Engineering; 2022, 22, 3; 81--90
1897-3310
2299-2944

Pojawia się w:

Archives of Foundry Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Admixture diffusion in a two-phase random nonhomogeneous stratified layer

Autorzy:

Chaplia, Y.
Chernukha, O.

Powiązania:

https://bibliotekanauki.pl/articles/281903.pdf

Data publikacji:

2001

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

admixture diffusion
random nonhomogeneous stratified layer

Opis:

Vertical admixture diffusion has been considered in a layer with random nonhomogeneous two-phase stratified structure of material. Different phase diffusion coefficients and phase densities have been taken into account as well as jump discontinuities of the diffusion coefficient at interphase boundaries. Averaging the obtained expressions for the admixture concentration has been done over the ensemble of sublayer configurations with equally probable distribution, and two particular cases of beta-distribution of phases in the body.
Dyfuzja substancji domieszkowej w dwufazowej warstwie losowo niejednorodnej. Rozważona jest jednowymiarowa (pionowa) dyfuzja substancji domieszkowej w warstwie tworzonej przez losowo-niejednorodny, dwufazowy materiał warstwowy.Przy konstruowaniu rozwiązań uwzględniono zarówno różnice współczynników dyfuzji i gęstości w różnych fazach, jak i nieciągłości współczynnika dyfuzji na granicach faz. Zgodnie z zaproponowanym podejściem przy rozwiązaniu zagadnienia brzegowego dyfuzji wpływ niejednorodności materiału sprowadzą się do rozpatrywania źródeł wewnętrznych masy, a same zagadnienie - do równania całkowego, które z koleji rozwiązano metodą rozwinięcia w szereg Neymana. Uśrednienieprzybliżonego rozwiązania po zbiorze konfiguracji faz, z których złożone jest ciało, wykonano dla równomiernego losowego rozkładu faz oraz dwóch szczegółowych przypadków rozkładu beta. Porównanie rozkładów uśrednionego pola koncentracji i koncentracji w jednorodnym ośrodku pokazało potrzebę wzięcia pod uwagę zarówno różnych dyfuzyjnych właściwości faz, jak i nieciągłości współczynnika dyfuzji na granicach faz w warunkach doskonałego kontaktu. Oprócz wyznaczono zależność uśrednionej koncentracji składnika domieszkowego od współczynników dyfuzji, gęstości i objętościowych udziału faz dla losowego rozkładu beta podwarstw.

Źródło:

Journal of Theoretical and Applied Mechanics; 2001, 39, 4; 929-946
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Markov operators: applications to diffusion processes and population dynamics

Autorzy:

Rudnicki, Ryszard

Powiązania:

https://bibliotekanauki.pl/articles/1208219.pdf

Data publikacji:

2000

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

Markov operator
asymptotic stability
diffusion process
partial differential equation

Opis:

This note contains a survey of recent results concerning asymptotic properties of Markov operators and semigroups. Some biological and physical applications are given.

Źródło:

Applicationes Mathematicae; 2000, 27, 1; 67-79
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

Nonlinear Diffusion Equation with Diffusion Coefficient Directly Proportional to Concentration of Impurities

Autorzy:

Janavičius, A. J.
Poškus, A.

Powiązania:

https://bibliotekanauki.pl/articles/2042120.pdf

Data publikacji:

2005-03

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

66.30.-h

Opis:

We analyzed a diffusion model based on the assumption that the sufficient condition for the mass flux at point x+L to be different from zero is a nonzero value of the impurity gradient and of impurity concentration at point x. In our model, the length of the jump of diffusing particles from one equilibrium position to another has a defined value L. By describing variation of impurity concentration with time when the frequency of the jumps depends on coordinates and L, the nonlinear diffusion equation was derived. We found that the diffusion coefficient in this nonlinear equation is directly proportional to the concentration of impurities, as it had been proposed in earliest papers. The derived nonlinear diffusion equation was solved numerically for the case of spherical symmetry.

Źródło:

Acta Physica Polonica A; 2005, 107, 3; 519-524
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

A Diffusion Model of Binary Systems Controlled by Chemical Potential Gradient

Autorzy:

Wróbel, Marek
Burbelko, Andriy

Powiązania:

https://bibliotekanauki.pl/articles/2105206.pdf

Data publikacji:

2022

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

diffusion
modelling
CALPHAD
chemical potential

Opis:

The paper presents a model of diffusion in a single phase with chemical potential gradient as the driving force of the process. Fick’s laws are strictly empirical and the assumption that the concentration gradients are the driving forces of diffusion is far from precise. Instead, the gradient of chemical potential μi of component i is the real driving force. The matter of governing equations of models that incorporate this approach will be raised and discussed in this article. One of more important features is the ability to acquire results where diffusion against the concentration gradient may occur. The presented model uses the Finite Difference Method (FDM) and employs the CALPHAD method to obtain chemical potentials. The calculations of chemical potential are carried out for instant conditions – temperature and composition – in the entire task domain by Thermo-Calc via a TQ-Interface. Then the heterogeneity of chemical potentials is translated into mass transfer for each individual element. Calculations of two modelling tasks for one-dimension diffusion field were carried out. First: isothermal conditions with linear initial composition distribution and second: constant temperature gradient with uniform chemical composition in the specimen. Results for two binary solid solutions: Fe-C and Fe-Si, in the FCC phase for the given tasks will be presented. Modelling allows us to estimate the time needed to reach a desired state in a particular equilibrium or quasi-equilibrium state. It also shows the path of the composition change during the process. This can be used to determine whether the system at some point is getting close to the formation of another phase due to significant deviation from its initial conditions.

Źródło:

Journal of Casting & Materials Engineering; 2022, 6, 2; 39--44
2543-9901

Pojawia się w:

Journal of Casting & Materials Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Teoria dyfuzji wieloskładnikowej w ośrodkach płynnych. Cz. 2, Zastosowanie konstytutywnych równań dyfuzji wieloskładnikowej
Theory of multicomponent diffusion in fluid systems. Part 2, Applications of the constitutive equations of multicomponent diffusion

Autorzy:

Burghardt, A.

Powiązania:

https://bibliotekanauki.pl/articles/306041.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Instytut Inżynierii Chemicznej PAN

Tematy:

mechaniczna teoria dyfuzji
równania konstytutywne
siły napędowe dyfuzji
mechanical theory of diffusion
constitutive equations
driving forces of diffusion

Opis:

Konstytutywne równania dyfuzji wieloskładnikowej wyprowadzone w części pierwszej opracowania [1] w oparciu o mechaniczną teorię dyfuzji mogą być stosowane do dowolnych mieszanin izotropowych, takich jak gazy pod niskim i wysokim ciśnieniem, ciecze, roztwory elektrolitów i polimerów oraz plazma. Dlatego w tej części (drugiej) opracowania przedstawiono przykłady zastosowań zależności teoretycznych wyprowadzonych w części pierwszej do izotropowych układów płynnych wymienionych powyżej.
The constitutive equations of multicomponent diffusion derived in the first part of the study [1] basing of the mechanical theory of diffusion are applicable to any isotropic fluid mixture like gases under low and high pressure, liquids, electrolyte and polymeric solutions as well as plasma. Therefore in this (second) part of the study examples of application of the theoretical expressions derived in the first part are presented with respect to the fluid systems mentioned above.

Źródło:

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk; 2017, 21; 15-32
1509-0760

Pojawia się w:

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Change of composition and structure of diffusion chrome coating during friction

Autorzy:

Sharifov, Z. Z.
Bashirov, F. R.

Powiązania:

https://bibliotekanauki.pl/articles/359817.pdf

Data publikacji:

2013

Wydawca:

Akademia Morska w Szczecinie. Wydawnictwo AMSz

Tematy:

diffusion
friction
phase matrix

Opis:

The paper studied the behavior of the composition and structure of the diffusion of chromium coatings in sliding. It was found that the strain in friction generates the secondary structure of chromium coatings and as a result of the deformation effect wear is accelerated due to separation of the coating.

Źródło:

Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2013, 33 (105); 96-99
1733-8670
2392-0378

Pojawia się w:

Zeszyty Naukowe Akademii Morskiej w Szczecinie

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

Tytuł:

Drug diffusion transport through human skin

Autorzy:

Walicka, A.
Iwanowska-Chomiak, B.

Powiązania:

https://bibliotekanauki.pl/articles/265397.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

ludzka skóra
dyfuzja
dostarczanie leków
drug delivery
human skin
diffusion

Opis:

The stratum corneum (SC) forms the outermost layer of the human skin and is essentially a multilamellar lipid milieu punctuated by protein-filled corneocytes that augment membrane integrity and significantly increase membrane tortuosity. The lipophilic character of the SC, coupled with its intrinsic tortuosity, ensure that it almost always provides the principal barrier to the entry of drug molecules into the organism. Drugs can be administered either as suspensions or as solutions and the formulation can range in complexity from a gel or and ointment to a multilayer transdermal path. In this paper, we discuss theoretical principles used to describe transdermal release and we show that relatively simple membrane transport models based on the appropriate solution to the Fick’s second law of diffusion can be used to explain drug release kinetics into such a complex biological membrane as the human skin. To apply the Fick’s law we introduced into our considerations a brick-and-mortar model with two factors of tortuosity. Assuming that the mortar thickness is variable we also introduced the hindrance factor allowing us to model this variability. Having the modified Fick’s equation we presented its general solution and two special cases of this solution frequently applicable in permeation experiments. It seems that the solutions presented herein better approximate the real conditions of drug delivery then these well known.

Źródło:

International Journal of Applied Mechanics and Engineering; 2018, 23, 4; 977-988
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

Ocena współczynnika dyfuzji par węglowodorów w gruncie
Prediction of diffusion coefficient of hydrocarbon vapour in soil

Autorzy:

Fąfara, Z.

Powiązania:

https://bibliotekanauki.pl/articles/300210.pdf

Data publikacji:

2010

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

grunt sypki
migracja węglowodorów
dyfuzja par węglowodorów
współczynnik dyfuzji
loose soil
hydrocarbon migration
hydrocarbon vapour diffusion
diffusion coefficient

Opis:

Podczas migracji substancji ropopochodnej w gruncie, w pewnych sytuacjach dyfuzja par węglowodorów może odgrywać istotną rolę, decydując o zasięgu skażenia oraz stwarzając niebezpieczeństwo wybuchu. Z tego względu konieczna jest znajomość prędkości dyfuzji par węglowodorów w przestrzeni porowej gruntu dla właściwej oceny tych zagrożeń. Wykonano pomiary laboratoryjne prędkości dyfuzji par węglowodorów w specjalnie wyselekcjonowanych modelach ośrodka gruntowego. Źródło węglowodorów stanowiła etylina. Stwierdzono, że współczynnik dyfuzji silnie zależy od rodzaju gruntu. Następnie metodami statystycznymi dopasowano zależność regresyjną pozwalającą na ocenę współczynnika dyfuzji par węglowodorów na podstawie parametrów opisujących skład granulometryczny gruntu - powierzchnia właściwa gruntu i średnica efektywna ziaren. Uzyskane równania cechują się bardzo wysokim stopniem dopasowania do danych eksperymentalnych i z powodzeniem mogą być użyte podczas numerycznego modelowania procesu migracji węglowodorów w gruncie.
Diffusion of hydrocarbon vapour can be sometimes very important during numeric modeling of migration of oil contaminations in the soil. It decides on pollution range and zone of danger of explosion. Therefore, acquaintance of diffusion speed of hydrocarbon vapour in soil is indispensable for proper estimate these threats. There are made some laboratory measurements of diffusion speed of hydrocarbon vapour in specially selected models of soil. The ethylene was the hydrocarbon source. As it happens, that the diffusion coefficient is depends on kind of soil very strong. Next it was adjusted the regressive dependence to estimate the diffusion coefficient of hydrocarbon vapour using soil composition parameters - the pore surface and the effective diameter of grains. Get are featured for pilot data equaling very high degree of adjusting and there can be used with success during the numeric modeling process of migration of hydrocarbon in soil.

Źródło:

Wiertnictwo, Nafta, Gaz; 2010, 27, 1--2; 147-154
1507-0042

Pojawia się w:

Wiertnictwo, Nafta, Gaz

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

Uwalnianie środków aktywnych z hydrożeli - model dyfuzyjny i dyfuzyjno-desorpcyjny
Active agent release from hydrogels - diffusion and diffusion-desorption models

Autorzy:

Nawrotek, K.
Modrzejewska, Z.
Zarzycki, R

Powiązania:

https://bibliotekanauki.pl/articles/2073408.pdf

Data publikacji:

2013

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

modelowanie matematyczne
dyfuzja
adsorpcja
hydrożel
mathematical modelling
diffusion
adsorption
hydrogel

Opis:

Przedstawiono dwa modele uwalniania środków aktywnych z hydrożeli znany model dyfuzyjny oraz opracowany nowy model dyfuzyjno-desorpcyjny. Model ten uwzględnia procesy desorpcji z powierzchni fazy stałej matrycy oraz procesy dyfuzyjne zachodzące w porach matrycy. Kinetykę uwalniania opisano za pomocą współczynnika dyfuzji środka aktywnego v cieczy wypełniającej pory oraz współczynnika wnikania masy, który odpowiada szybkości desorpcji składnika aktywnego z powierzchni porów, przykładową symulację dla surowiczej albuminy wołowej (BSA) wykonano w programie MATLAB metodą różnic skończonych.
The paper presents two models of release of active agents from hydrogels: the known diffusion model and a developed new diffusion-desorption model. The later model takes into account desorption processes from the surface of solid phase matrix and diffusion processes taking place in the matrix pores. The release kinetics is described by means of the diffusion coefficient of active agent in liquid filling the pores, and the mass transfer coefficient which corresponds to the desorption rate of active ingredient from the surface of pores. An exemplary simulation for bovine serum albumin (BSA) was performed in MATLAB using the finite differences method.

Źródło:

Inżynieria i Aparatura Chemiczna; 2013, 6; 548--549
0368-0827

Pojawia się w:

Inżynieria i Aparatura Chemiczna

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

Morphophonological reduction in Swahili: the pressure of frequency and lexical diffusion

Autorzy:

Kraska-Szlenk, Iwona

Powiązania:

https://bibliotekanauki.pl/articles/969694.pdf

Data publikacji:

2010-12-10

Wydawca:

Uniwersytet Warszawski. Wydział Orientalistyczny. Katedra Języków i Kultur Afryki

Tematy:

Morphophonological reduction
Swahili language
frequency and lexical diffusion

Opis:

The article discusses a number of morphophonological alternations in Swahili which vary as to their scope and degree of regularity. It is argued that the allomorphy between syllabic and non-syllabic variants of some morphemes is due to phonological reduction which affects high frequency lexical items first and gradually extends on others by way of lexical diffusion. The analysis is supported by comparing the data of Standard Swahili to less conservative colloquial varieties and non-standardized local dialects, in which reductions are more advanced. The analysis contributes to a better comprehension of synchronic allomorphy and it also sheds light on the mechanism of diachronic change.

Źródło:

Studies in African Languages and Cultures; 2010, 44; 83-102
2545-2134
2657-4187

Pojawia się w:

Studies in African Languages and Cultures

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Diffusion limit for the phenomenon of random genetic drift

Autorzy:

Marciniak, Anna

Powiązania:

https://bibliotekanauki.pl/articles/1208221.pdf

Data publikacji:

2000

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

genetic drift
telegraph equations
singularly perturbed systems
diffusion equation
random walk

Opis:

The paper deals with mathematical modelling of population genetics processes. The formulated model describes the random genetic drift. The fluctuations of gene frequency in consecutive generations are described in terms of a random walk. The position of a moving particle is interpreted as the state of the population expressed as the frequency of appearance of a specific gene. This leads to a continuous model on the microscopic level in the form of two first order differential equations (known as the telegraph equations). Applying the modified Chapman-Enskog procedure we show the transition from this system to a macroscopic model which is a diffusion type equation. Finally, the error of approximation is estimated.

Źródło:

Applicationes Mathematicae; 2000, 27, 1; 81-101
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

The quantum diffusion of carbon in alfa-iron in low temperature

Autorzy:

Dąbrowski, L.
Andreev, A.
Georgiev, M.

Powiązania:

https://bibliotekanauki.pl/articles/147484.pdf

Data publikacji:

2006

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

carbon
diffusion
tunneling
adiabatic
polaron

Opis:

Recent experimental data on the diffusion coefficient of carbon in á-iron below liquid nitrogen temperature (LNT) question the classical approach to the observed temperature dependence. As the temperature is lowered below LNT, the diffusion constant tends to a nearly temperature-independent value rather than continuing its activated trend. The low temperature branch is apparently characteristic of a quantum mechanical process dominated by tunneling in ground state. Concomitantly we apply an occurrence-probability approach to describing the overall temperature dependence as a single continuous rate. Within the adiabatic approximation the electronic eigenvalue depending parametrically on the nuclear coordinates is taken to be the potential energy to control the motion of the nuclei. The resulting rate involves all horizontal-tunneling energy-conserving elastic transitions at the quantized energy levels of the migrating atom. A small though not negligible slope in the temperature dependence as the temperature is raised below 100 K is dealt with by complementing for the rate of a parallel one-phonon inelastic-tunneling process in excess to the basic elastic-tunneling rate. Our combined approach agrees well with the experimental data. In particular, the frequency of the coupled vibration is obtained virtually identical to the carbon vibrational frequency from inelastic neutron scattering data. The migrational barrier is also found to be within the limits expected for alfa-iron.

Źródło:

Nukleonika; 2006, 51, 2; 93-99
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Diffusion of innovations in developing countries: blockchain case study

Autorzy:

Sztokfisz, Barbara

Powiązania:

https://bibliotekanauki.pl/articles/570024.pdf

Data publikacji:

2019

Wydawca:

Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu

Tematy:

blockchain
distributed ledger technology
developing countries
economic growth
diffusion of innovations

Opis:

Distributed Ledger Technologies (DLTs) have become a topic that is being more and more discussed in political, economic and scientific discourses. , also within economic sciences. Their potential to redefine many processes in the economy is growing, and there is a consensus in the scientific community about their revolutionary character. Blockchain is one of the DLTs and one of the breakthrough technologies distinctive for the Fourth Industrial Revolution. The aim of the paper is to draw attention to the potential of blockchain technology for developing countries and how it can contribute to the improvement of quality of life and fighting poverty. Following Schwab’s thesis, “the extent to which society embraces technological innovation is a major determinant of progress”. Therefore, developing countries should not disregard the potential of blockchain technology that can solve a lot of current problems and provide access to previously unreachable services with a relatively low cost (both implementation and subsequent maintenance cost).

Źródło:

Ekonomia XXI Wieku; 2019, 1 (21); 60-74
2353-8929

Pojawia się w:

Ekonomia XXI Wieku

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Gradient Observability for Diffusion Systems

Autorzy:

Zerrik, E. H.
Bourray, H.

Powiązania:

https://bibliotekanauki.pl/articles/908195.pdf

Data publikacji:

2003

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

informatyka
diffusion system
observability
regional gradient observability
gradient strategic sensor
gradient reconstruction

Opis:

The aim of this paper is to study regional gradient observability for a diffusion system and the reconstruction of the state gradient without the knowledge of the state. First, we give definitions and characterizations of these new concepts and establish necessary conditions for the sensor structure in order to obtain regional gradient observability. We also explore an approach which allows for a regional gradient reconstruction. The developed method is original and leads to a numerical algorithm illustrated by simulations.

Źródło:

International Journal of Applied Mathematics and Computer Science; 2003, 13, 2; 139-150
1641-876X
2083-8492

Pojawia się w:

International Journal of Applied Mathematics and Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

Modeling the Diffusion of Dichlorvos through Human Stomach Lining

Autorzy:

Bello, O. D.
Oluwatusin, O. O.

Powiązania:

https://bibliotekanauki.pl/articles/1193343.pdf

Data publikacji:

2021

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Analytical solutions
Concentration
Dichlorvos
Diffusion
Mathematical modeling

Opis:

Dichlorvos is the main poison in sniper pesticide which has produced negative effects especially among youths in recent times. The poisonous effects of dichlorvos on humans require urgent studies to combat the damaging impacts among humans. However, the limitations of carrying out experiments on human test subjects request the quest for alternative approach. Such approach can be made through modeling the transport of dichlorvos in the human body and the resulting negative effect. Therefore, this work presents mathematical modeling for the diffusion of dichlorvos through the human stomach lining. The model is set up to determine the amount of dichlorvos that leaves the stomach through diffusion alone and the health effects various concentration of the poison has on humans. Two cases are studied in order to captivate the effects of dichlorvos poisoning for two different scenarios. The initial condition is set to 0.05L and different driving forces is used to model the scenarios in spherical coordinates. The governing equation is derived from Fick’s first law and is solved analytically, a numerical solution is obtained using MATLAB’s pdepe solver and graphs are plotted for the two cases. From the results it is observed that about 14.4% of dichlorvos is diffused through the stomach lining in about 60hours for the first case while for the second case, the periodic intake of water along with dichlorvos gradually reduces the dichlorvos concentration in the stomach. These results show consistency with some experimental results from literature. Therefore, the model can be used in addition to the modes of treatment obtained from literature to predict the concentration of dichlorvos in a person and also proffer a life-saving treatment.

Źródło:

World Scientific News; 2021, 154; 34-47
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Sound diffuser made of acoustic metamaterial: numerical and experimental investigation

Autorzy:

Rubacha, Jarosław

Powiązania:

https://bibliotekanauki.pl/articles/2146653.pdf

Data publikacji:

2021

Wydawca:

Politechnika Poznańska. Instytut Mechaniki Stosowanej

Tematy:

metamaterial
sound diffusion
diffusion coefficient
metamateriał
dyfuzja dźwięku
współczynnik dyfuzji

Opis:

The use of metamaterials in room acoustics is becoming more and more popular. Their advantage is the possibility of adjusting the parameters of the systems in the desired frequency range and the reduction of dimensions compared to the existing solutions. This paper discusses the numerical design and experimental verification of sound diffuser based on the acoustic metamaterials: a slit with added quart-wave length resonator. The transfer matrix method is used to make a numerical model of the metamaterial cell, which was used to build a model of a diffuser composed of N = 7 cells. Then, the dimensions of the diffuser were optimized to obtain the sound diffusion in a wide frequency range. The sound dispersion coefficient was also calculated using the FEM method. The numerical results were compared with the measurements and it was shown that it is possible to make a broadband sound diffuser with the use of metamaterials.

Źródło:

Vibrations in Physical Systems; 2021, 32, 2; art. no. 2021207
0860-6897

Pojawia się w:

Vibrations in Physical Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Inverse Model for the Solute Micro-Field Formation during Self-Propagating High Temperature Reaction

Autorzy:

Wołczyński, W.

Powiązania:

https://bibliotekanauki.pl/articles/351234.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

diffusion equation
diffusion barrier
self-propagating synthesis

Opis:

A new thermodynamic description for the self-propagating high temperature synthesis (SHS - reaction) is presented in the “inverse” version. This description is worked out for the diffusion barrier, thickness of which is at the limit, i.e. its value is infinitesimally small. The solution to the diffusion equation delivered in the description can be easily extended for the diffusion barrier of a greater thickness. The Ni/Al multi-layers system is treated as a virtual eutectic alloy solidifying with the rate equal to that involved by the self-propagating reaction. It is suggested to inverse the curves obtained for solidification in order to characterize the melting completed by the formation of the AlNi - intermetallic phase required in the self-propagating synthesis.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 1; 141-147
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Entropy generation on mhd flow of Powell-Eyring fluid between radially stretching rotating disk with diffusion-thermo and thermo-diffusion effects

Autorzy:

Khan, N. A.
Aziz, S.
Ullah, S.

Powiązania:

https://bibliotekanauki.pl/articles/386796.pdf

Data publikacji:

2017

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

axisymmetric flow
entropy generation
stretching disk
Powell-Eyring fluid
diffusion

Opis:

An investigation is performed for an alyzing the effect of entropy generation on the steady, laminar, axisymmetric flow of an incompressible Powell-Eyring fluid. The flow is considered in the presence of vertically applied magnetic field between radially stretching rotating disks. The Energy and concentration equation is taking into account to investigate the heat dissipation, Soret, Dufour and Joule heating effects. To describe the considered flow non-dimensionalized equations, an exact similarity function is used to reduce a set of the partial differential equation into a system of non-linear coupled ordinary differential equation with the associated boundary conditions. Using homotopy analysis method (HAM), an analytic solution for velocity, temperature and concentration profiles are obtained over the entire range of the imperative parameters. The velocity components, concentration and temperature field are used to determine the entropy generation. Plots illustrate important results on the effect of physical flow parameters. Results obtained by means of HAM are then compared with the results obtained by using optimized homotopy analysis method (OHAM). They are in very good agreement.

Źródło:

Acta Mechanica et Automatica; 2017, 11, 1; 20-32
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

Observation of "Diffusion Modes" in Measurement of the Diffusion Coefficient of Cesium in Noble Gases

Autorzy:

Rudecki, P.

Powiązania:

https://bibliotekanauki.pl/articles/2029276.pdf

Data publikacji:

2001-12

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

82.56.Lz
34.90.+q

Opis:

A set of experiments investigating diffusion of alkali atoms in the noble gases is reported. A cesium gradient in the cell was induced by electrodeless pulse discharge. In the transient signal of absorption, corresponding to the $\text{}^{2}$S$\text{}_{1}\text{}_{/}\text{}_{2}$ -n$\text{}^{2}$P$\text{}_{J}$ transitions, five diffusion modes were observed. The diffusion coefficient D of cesium in helium and argon has been measured in a spherical cell filled with a buffer gas of 2.5 to 30 hPa and for temperatures in the range from 275 K to 400 K.

Źródło:

Acta Physica Polonica A; 2001, 100, 6; 915-923
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

Applications of the fractional Sturm-Liouville difference problem to the fractional diffusion difference equation

Autorzy:

Malinowska, Agnieszka B.
Odzijewicz, Tatiana
Poskrobko, Anna

Powiązania:

https://bibliotekanauki.pl/articles/24200687.pdf

Data publikacji:

2023

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

anomalous diffusion
fractional diffusion equation
fractional calculus
difference equation
dyfuzja anomalna
równanie dyfuzji ułamkowe
rachunek ułamkowy
równanie różnicowe

Opis:

This paper deals with homogeneous and non-homogeneous fractional diffusion difference equations. The fractional operators in space and time are defined in the sense of Grünwald and Letnikov. Applying results on the existence of eigenvalues and corresponding eigenfunctions of the Sturm-Liouville problem, we show that solutions of fractional diffusion difference equations exist and are given by a finite series.

Źródło:

International Journal of Applied Mathematics and Computer Science; 2023, 33, 3; 349--359
1641-876X
2083-8492

Pojawia się w:

International Journal of Applied Mathematics and Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Properties of Tool Steel After Hybrid Treatment Connecting Diffusion Chromizing with the PVD Method

Autorzy:

Kasprzycka, E.
Bogdański, B.

Powiązania:

https://bibliotekanauki.pl/articles/351463.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

diffusion chromizing
PVD coating
carbide layer

Opis:

The objective of the research in this work was the modification of structure of carbide-type chromized layers, by the combination of diffusion chromizing with subsequent PVD treatment, consisting of chromium nitride deposition, carried out to improve their tribological properties. As a result, hybrid layers on the surface of tool steel were obtained. For comparison, the properties of single chromized carbide layers obtained in a diffusion chromizing process were tested. Investigations of layer microstructure, their mechanical properties, surface topography, adhesion of layers to the steel substrate, as well as tribological properties were conducted. The layer microstructure was characterized by X-ray diffraction and scanning electron microscopy. Topography of the layer surface was studied by an optical profilometer. The scratch test for investigations of layers adhesion to the steel substrate was used. Testing of tribological properties (linear wear) of the layers was performed by the three-cylinder-cone method. It was shown, that hybrid layers are characterized by a significantly smaller surface roughness than that of chromized carbide layers and their wear resistance improved almost twice with respect to carbide layers.

Źródło:

Archives of Metallurgy and Materials; 2019, 64, 1; 235-242
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

Diffusion of boron in cobalt sinters
Dyfuzja boru w spiekach kobaltu

Autorzy:

Borowiecka-Jamrozek, J.
Lachowski, J.

Powiązania:

https://bibliotekanauki.pl/articles/354296.pdf

Data publikacji:

2013

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

diffusion
sinter
cobalt
boronizing
dyfuzja
spiek
kobalt
bor

Opis:

The paper describes the process of diffusion taking place at the surface of sinters produced from Co Extrafine powder after saturation with boron. Boronizing was performed at a temperature of 950°C for 6 and 12 hours by applying B4C powder as a depositing source, NH4Cl + NaF as an activator and Al2O3 as an inert filler. The study involved determining the diffusion coefficient, which required analyzing the microstructure and thickness of the layers and the process time. The images obtained with a Leica DM-4000 optical microscope revealed a two-phase structure of the boride layers. The presence of the two phases, i.e. CoB and Co2B, was confirmed by X-ray diffraction (XRD). A model of diffusion of boron atoms into the cobalt substrate was developed assuming the reaction diffusion mechanism. This model was used to calculate the diffusion coefficient. It required taking account of the interatomic potentials of boron and cobalt. The calculation results were compared with the experimental data concerning the diffusion of boron in other materials.
W pracy przedstawiono wyniki badań procesu dyfuzji w warstwach powierzchniowych uzyskanych w wyniku nasycenia borem spieków otrzymanych z proszku kobaltu gatunku Co Extrafine. Warstwy otrzymano przy zastosowaniu proszkowej metody borowania opartej na wykorzystaniu mieszaniny o składzie: B4C jako składnik podstawowy stanowiący źródło boru, (NH4Cl + NaF) aktywator i Al2O3 jako wypełniacz. Zachowane były następujące parametry procesu: temperatura 950°C, czas 6h i 12h. Badania obejmowały wyznaczenie współczynnika dyfuzji w oparciu o strukturę, grubość uzyskanych i czas nasycenia warstw. Obserwacji naniesionych warstw dokonano za pomocą mikroskopu optycznego Leica DM-4000. Zdjęcia ujawniły dwufazową strukturę warstw borkowych. Badania rentgenowskie potwierdziły występowanie faz o składzie: CoB i Co2B. Zbudowano model dyfuzji atomów boru w strukturze kobaltu zakładając dyfuzję reaktywną. Obliczono współczynnik dyfuzji w oparciu o model atomowy dyfuzji wykorzystując potencjały oddziaływan pomiędzy atomami boru i kobaltu. Otrzymane wyniki porównano z danymi doświadczalnymi dyfuzji boru w innych materiałach.

Źródło:

Archives of Metallurgy and Materials; 2013, 58, 4; 1131-1136
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

The Ni-Al-Hf Multiphase Diffusion

Autorzy:

Romanowska, J.
Wierzba, B.
Markowski, J.
Zagula-Yavorska, M.
Sieniawski, J.

Powiązania:

https://bibliotekanauki.pl/articles/356143.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

NiAlHf system
reactive diffusion
simulation
aluminide coatings

Opis:

The generalized Darken method was applied to simulate the diffusion between γ-Ni| γ’-Ni₃Al and γ’-Ni₃Al|β-NiAl interfaces. The results of calculations were compared with the experimental concentration’s profiles of nickel, aluminum and hafnium in aluminide and hafnium doped aluminide coatings deposited by the CVD and PVD methods on pure nickel. The method deals with the Wagner’s integral diffusion coefficients and thermodynamic data - activities of components. The experimental results agree with the simulated ones.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 2A; 587-592
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 46.

Tytuł:

On the identification of diffusion coefficients

Autorzy:

Stoyan, Gisbert

Powiązania:

https://bibliotekanauki.pl/articles/1361928.pdf

Data publikacji:

1978

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Źródło:

Banach Center Publications; 1978, 3, 1; 367-377
0137-6934

Pojawia się w:

Banach Center Publications

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 47.

Tytuł:

Diffusion paths between product life-cycles in the European phonographic market

Autorzy:

Jarynowski, A.
Buda, A.

Powiązania:

https://bibliotekanauki.pl/articles/206745.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

epidemiology modeling
social network analysis
cultural diffusion
music charts

Opis:

We have investigated the product life-cycles of almost 17 000 hit singles having appeared on the 12 biggest national phonographic markets in Europe including: Austria, Belgium, France, Germany, Ireland, Italy, Netherlands, Norway, Spain, Switzerland, Sweden, and the United Kingdom. We have considered weekly singles charts from the last 50 years (1966-2015) in each country. We analyzed the spread of hit singles popularity (chart topping) as an epidemiological process, taking place in various European countries. Popularity of the hit singles is contagious in the sense of moving from one country to another. Thus, we consider time delays between the initial hit single release and reaching the highest position on consecutive national singles charts. We create a directed network of countries, this network representing the transmission of the hit singles popularity between countries. This is obtained by simulating the most likely paths and picking up the most frequent links. A country of initial hit single release is considered as a source of infection. Our algorithm builds up the spanning trees by attaching new nodes. The probability of attachment depends on infectivity of previous nodes from the tree corresponding to their: 1) market size; 2) distance in time between the new node and the potential spreaders. Thus, we obtain a network of popularity spread with: a hub – the UK, a bridge – the Netherlands, and outliers – Italy and Spain. We have found a characteristic topology of hit singles popularity spread. On the top of this, the network of popularity spread has some typical properties of complex networks.

Źródło:

Control and Cybernetics; 2016, 45, 2; 225-237
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 48.

Tytuł:

A Neumann problem for a convection-diffusion equation on the half-line

Autorzy:

Biler, Piotr
Karch, Grzegorz

Powiązania:

https://bibliotekanauki.pl/articles/1207965.pdf

Data publikacji:

2000

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

Neumann problem
asymptotics of solutions.
convection-diffusion equation

Opis:

We study solutions to a nonlinear parabolic convection-diffusion equation on the half-line with the Neumann condition at x=0. The analysis is based on the properties of self-similar solutions to that problem.

Źródło:

Annales Polonici Mathematici; 2000, 74, 1; 79-95
0066-2216

Pojawia się w:

Annales Polonici Mathematici

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 49.

Tytuł:

Dwa typy dyfuzji innowacji i ich ontologiczne założenia
The two types of diffusion of innovations and their ontological assumptions

Autorzy:

Mikołajec, J.

Powiązania:

https://bibliotekanauki.pl/articles/326885.pdf

Data publikacji:

2014

Wydawca:

Politechnika Śląska. Wydawnictwo Politechniki Śląskiej

Tematy:

dyfuzja innowacji
dyfuzjonizm
przestrzeń geograficzna
dyfuzja międzykulturowa
system społeczny
diffusion of innovations
diffusionism
geographical space
cultural diffusion
social system

Opis:

Istnieją dwie koncepcje dyfuzji innowacji o odrębnych założeniach ontologicznych i konsekwencjach historiozoficznych. Tradycyjny dyfuzjonizm w antropologii na przełomie XIX i XX wieku był związany z wielokulturowością. Nowoczesna teoria dyfuzji innowacji zakłada istnienie pojedynczej kultury.
There are two conceptions of innovations diffusion having separate ontological foundations and historiosophical consequences. Traditional diffusionism in anthropology at the turn of the 19th and 20th centuries was related to multiculturalism. The modern theory of the innovations diffusion assumes the existence of a single culture.

Źródło:

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska; 2014, 72; 125-134
1641-3466

Pojawia się w:

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 50.

Tytuł:

Solutions to Time-Fractional Diffusion-Wave Equation in Spherical Coordinates

Autorzy:

Povstenko, Y.

Powiązania:

https://bibliotekanauki.pl/articles/386572.pdf

Data publikacji:

2011

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

transformata Laplace'a
transformata Fouriera
równanie dyfuzji
Laplace transform
Fourier transform
diffusion equation

Opis:

Solutions to time-fractional diffusion-wave equation with a source term in spherical coordinates are obtained for an infinite medium. The solutions are found using the Laplace transform with respect to time t, the finite Fourier transform with respect to the angular coordinate , the Legendre transform with respect to the spatial coordinate , and the Hankel transform of the order n+1/2 with respect to the radial coordinate . In the central symmetric case with one spatial coordinate the obtained results coincide with those studied earlier.

Źródło:

Acta Mechanica et Automatica; 2011, 5, 2; 108-111
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 51.

Tytuł:

Commentary on: The usefulness and limitations of diffusion tensor imaging – a review study

Autorzy:

Szmuda, Tomasz
Ali, Shan

Powiązania:

https://bibliotekanauki.pl/articles/895811.pdf

Data publikacji:

2020-01-09

Wydawca:

Gdański Uniwersytet Medyczny

Tematy:

Diffusion Tensor Imaging
cerebellopontine angle
facial nerve
tractography

Źródło:

European Journal of Translational and Clinical Medicine; 2019, 2, 2; 85-86
2657-3148
2657-3156

Pojawia się w:

European Journal of Translational and Clinical Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 52.

Tytuł:

Global existence and asymptotic behavior for a nonlinear degenerate SIS model

Autorzy:

Ziane, T. A.

Powiązania:

https://bibliotekanauki.pl/articles/952842.pdf

Data publikacji:

2013

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

reaction diffusion systems
degenerate diffusion
global existence
asymptotic behavior
population dynamics

Opis:

In this paper we investigate the global existence and asymptotic behavior of a reaction diffusion system with degenerate diffusion arising in the modeling and the spatial spread of an epidemic disease.

Źródło:

Opuscula Mathematica; 2013, 33, 4; 615-630
1232-9274
2300-6919

Pojawia się w:

Opuscula Mathematica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 53.

Tytuł:

Behaviour of global solutions for a system of reaction-diffusion equations from combustion theory

Autorzy:

Badraoui, Salah

Powiązania:

https://bibliotekanauki.pl/articles/1338841.pdf

Data publikacji:

1999

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

global existence
boundedness
reaction-diffusion equations
large time behaviour

Opis:

We are concerned with the boundedness and large time behaviour of the solution for a system of reaction-diffusion equations modelling complex consecutive reactions on a bounded domain under homogeneous Neumann boundary conditions. Using the techniques of E. Conway, D. Hoff and J. Smoller [3] we also show that the bounded solution converges to a constant function as t → ∞. Finally, we investigate the rate of this convergence.

Źródło:

Applicationes Mathematicae; 1999, 26, 2; 133-150
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 54.

Tytuł:

Dynamics, control, stability, diffusion and synchronization of modified chaotic Colpitts oscillator

Autorzy:

Rasappan, Suresh
Niranjan Kumar, K. A.

Powiązania:

https://bibliotekanauki.pl/articles/1845526.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

chaos
Colpitts oscillator
Lyapunov exponent
diffusion
stability
synchronization

Opis:

The purpose of this paper is to introduce a new chaotic oscillator. Although different chaotic systems have been formulated by earlier researchers, only a few chaotic systems exhibit chaotic behaviour. In this work, a new chaotic system with chaotic attractor is introduced. It is worth noting that this striking phenomenon rarely occurs in respect of chaotic systems. The system proposed in this paper has been realized with numerical simulation. The results emanating from the numerical simulation indicate the feasibility of the proposed chaotic system. More over, chaos control, stability, diffusion and synchronization of such a system have been dealt with.

Źródło:

Archives of Control Sciences; 2021, 31, 3; 731-759
1230-2384

Pojawia się w:

Archives of Control Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 55.

Tytuł:

Solution of diffusion-advection equation of radon transport in many-layered geological media

Autorzy:

Yakovleva, V. S.
Parovik, R. I.

Powiązania:

https://bibliotekanauki.pl/articles/148852.pdf

Data publikacji:

2010

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

radon
diffusion
advection
transport
modeling
soil

Opis:

Radon transport modeling in geological media is an important tool for solving problems and tasks of radioecology and geophysics. Comparison of radon field time series obtained by numerical and experimental methods is one of the most common and widely applicable ways to analyze the influence of state and variability of meteorological, electrical and actinometric parameters of atmosphere, cosmic weather factors, variations of deflected mode of geological medium on the level and variations of radon field. The solutions of stationary and non-stationary diffusion-advection equations of radon transport in many-layered geological media by numerical methods, notably by integro-interpolation method (balance method) are presented. The peculiarity of radon transport in many-layered media is taken into account in the developed numerical model. This peculiarity is connected with the transport equation coefficients which can change very rapidly at the border of two adjacent layers, i.e. they can be discontinuous at the borders of each layer that can be caused by parameters of soils greatly differing in value (density, porosity, radium content, diffusion and emanation coefficients). The present work is provided with an example of application of the developed numerical model for solving a practical problem on assessment of influence of deep seated uranium-containing rock on the value of radon volumetric activity at the depth of less-than or equal to 1 m. The article considers non-stationary numerical model calculations showing at what time moments the distribution curves of radon volumetric activity coincide with stationary regime of radon transport in geological media. The validity of the developed numerical solution has been confirmed by these calculations.

Źródło:

Nukleonika; 2010, 55, 4; 601-606
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 56.

Tytuł:

Growth pole theory as a concept based on innovation activity development and knowledge diffusion

Autorzy:

Wojnicka-Sycz, Elżbieta

Powiązania:

https://bibliotekanauki.pl/articles/1831421.pdf

Data publikacji:

2013

Wydawca:

Politechnika Gdańska

Tematy:

growth pole theory
development factors
innovation
knowledge diffusion

Opis:

Innovation activity and knowledge diffusion are key development factors in territorial growth poles and crucial, but not enough stressed in the original growth pole theory. In the article thoughts of the authors of the original growth pole theory connected with knowledge and innovation are presented. The original theory is than adjusted to the modern requirements of the knowledge based economy by presentation of the model of territorial growth pole as a system of development factors and analysis of the real impact of theoretical development factors on economic growth based on literature review.

Źródło:

Przedsiębiorstwo we współczesnej gospodarce - teoria i praktyka; 2013, 3, 6; 17-33
2084-6495

Pojawia się w:

Przedsiębiorstwo we współczesnej gospodarce - teoria i praktyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 57.

Tytuł:

Diffusion Permeability of Cation-Exchange Membrane in Different Solutions

Autorzy:

Gubari, Mohammed Qader
Abdulkarim, Abdullah Adnan
Alekseeva, Nadezda Vyacheslavovna

Powiązania:

https://bibliotekanauki.pl/articles/1955486.pdf

Data publikacji:

2021

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

cation exchange membrane
temperature
concentration
diffusion permeability

Opis:

This work is devoted to study the effect of thermal conditions and concentrations on the diffusion permeability of a cation exchange membrane (MK-40) using sodium chloride (NaCl), sodium acetate (C2H3NaO2) and acetic acid (CH3COOH) solutions, which are usually highly concentrated components of pigment yellow 13 of industrial wastewater. A cell containing two compartments was used to analyze the properties of membrane. The results showed that the maximum diffusion permeability coefficients for NaCl, C2H3NaO2, and CH3COOH were 6.08×10-9 m2/s, 13.29×10-11 m2/s, and 25.95×10-11 m2/s, respectively. The increase in the CH3COOH solution concentration was found to improve the diffusion permeability. However, the NaCl and C2H3NaO2 solutions exhibited decreases in diffusion permeability with solution concentration. There was a significant increase in diffusion permeability with temperature.

Źródło:

Journal of Ecological Engineering; 2021, 22, 8; 140-145
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 58.

Tytuł:

Differential quadrature methodfor some diffusion-reaction problems

Autorzy:

Szukiewicz, Mirosław K.

Powiązania:

https://bibliotekanauki.pl/articles/184877.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical algorithm
boundary value problem
reaction-diffusion equation
algorytm numeryczny
wartość graniczna
równanie dyfuzji reakcyjnej

Opis:

In the paper, differential quadrature method (DQM) is used to find numerical solutions of reaction-diffusion equations with different boundary conditions. The DQM-method changes the reaction-diffusion equation (ordinary differential equation) into a system of algebraic equations. The obtainedsystem is solved using built-in procedures of Maple®(Computer Algebra System-type program).Calculations were performed with Maple®program. The test problems include reaction-diffusionequation applied in heterogeneous catalysis. The method can be employed even in relatively hard tasks(e.g. ill-conditioned, free boundary problems).

Źródło:

Chemical and Process Engineering; 2020, 41, 1; 3-11
0208-6425
2300-1925

Pojawia się w:

Chemical and Process Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 59.

Tytuł:

Dynamics, control, stability, diffusion and synchronization of modified chaotic Colpitts oscillator

Autorzy:

Rasappan, Suresh
Niranjan Kumar, K. A.

Powiązania:

https://bibliotekanauki.pl/articles/1845536.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

chaos
Colpitts oscillator
Lyapunov exponent
diffusion
stability
synchronization

Opis:

The purpose of this paper is to introduce a new chaotic oscillator. Although different chaotic systems have been formulated by earlier researchers, only a few chaotic systems exhibit chaotic behaviour. In this work, a new chaotic system with chaotic attractor is introduced. It is worth noting that this striking phenomenon rarely occurs in respect of chaotic systems. The system proposed in this paper has been realized with numerical simulation. The results emanating from the numerical simulation indicate the feasibility of the proposed chaotic system. More over, chaos control, stability, diffusion and synchronization of such a system have been dealt with.

Źródło:

Archives of Control Sciences; 2021, 31, 3; 731-759
1230-2384

Pojawia się w:

Archives of Control Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 60.

Tytuł:

Effect of Diffusion Annealing on Borides Layers Produced on XC38 Steel

Autorzy:

Rayane, K.
Allaoui, O.
Allaoui, A.

Powiązania:

https://bibliotekanauki.pl/articles/1031131.pdf

Data publikacji:

2017-09

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

boriding
molten salts
annealing diffusion
XC38 steel

Opis:

In this work, we present a study of the effect of diffusion annealing at 700°C for 1 h on the nature and properties of boride layers obtained on XC38 steel through a molten salt consisting of borax (Na₂B₄O₇) and boron carbide (B₄C). We evaluated the changes brought by the diffusion annealing on the morphology of the boride layer, the thickness of this layer, the distribution of elements in the steel, and the hardness. Comparing the results obtained allowed concluding that the diffusion annealing will completely transform the two-phase layer formed of FeB and Fe₂B borides in a single-phase layer consisting of single boride Fe₂B. The transformation of the two-phase boride into a single-phase boride is done with an increase in thickness of about 30% compared to the initial thickness of the sample. The values of Si concentration obtained in the underlying zone after the diffusion annealing treatment are more important than those obtained in the same underlying zone of samples borided directly by immersion in molten salt consisting of borax and silicon carbide (SiC).

Źródło:

Acta Physica Polonica A; 2017, 132, 3; 521-523
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 61.

Tytuł:

Ekran akustyczny z powierzchnią dyfuzyjną
Acoustic Screen with Diffusion Surface

Autorzy:

Kamisiński, T.
Flach, A.
Rubacha, J.
Pilch, A.

Powiązania:

https://bibliotekanauki.pl/articles/143539.pdf

Data publikacji:

2010

Wydawca:

Stowarzyszenie Inżynierów i Techników Komunikacji Rzeczpospolitej Polskiej

Tematy:

drogi
hałas
ekrany
dyfuzja
roads
noise
screens
diffusion

Opis:

Ekrany akustyczne mogą odbijać, pochłaniać lub rozpraszać dźwięki. Ekran ze specjalnie zaprojektowaną powierzchnią dyfuzyjną ma wysoki stopień rozpraszania dźwięku. Ma również możliwość pochłaniania dźwięku dzięki komorom i systemem perforacji. Te właściwości umożliwiają zastosowanie ekranu do ochrony przed hałasem drogowym.
Acoustic screen can reflect, absorb or scatter a sound. Screen with especially designed diffusion surface gives high degree of sound scattering. It has also possibility of sound absorbing by mean of cells and perforation system. These characteristic features make possible the use of such screen for protection against road noise.

Źródło:

Drogownictwo; 2010, 12; 416-418
0012-6357

Pojawia się w:

Drogownictwo

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 62.

Tytuł:

Innovations in management accounting at the turn of the 20th and 21st century

Autorzy:

Wnuk-Pel, Tomasz

Powiązania:

https://bibliotekanauki.pl/articles/658132.pdf

Data publikacji:

2011

Wydawca:

Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego

Tematy:

management accounting
innovations
diffusion
activity-based costing diffusion

Opis:

Diffusion of innovative management accounting methods constitutes an incredibly interesting and a widely presented subject in literature all over the world. In the context of significance of innovative management accounting methods diffusion, the following objective of the article has been formulated – the article aims to analyze the concept of innovations in management accounting and analyze their significance and diffusion at the turn of the 20th and 21st century. In order to reach the aim, an analysis of the concept of management accounting innovations has been attempted; attention has been paid to the fact that the innovations are delayed when compared to technical innovations, the results of the delay have also been presented. Analysis of findings of the research on the use of innovative methods such as ABC/M, BSC, TQM and analysis of methods of company and individual employees’ performance evaluation has been made.

Źródło:

Acta Universitatis Lodziensis. Folia Oeconomica; 2011, 257
0208-6018
2353-7663

Pojawia się w:

Acta Universitatis Lodziensis. Folia Oeconomica

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 63.

Tytuł:

Nonlinear Many-Staged Diffusion

Autorzy:

Janavičius, A.

Powiązania:

https://bibliotekanauki.pl/articles/1968915.pdf

Data publikacji:

1998-05

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

66.30.-h

Opis:

We considered and solved the nonlinear diffusion equation formerly. The more complicated but more useful task of many-staged diffusion is solved in this paper. The obtained solution satisfies the initial distribution of the impurities and can be generalized for many-staged diffusion. Using these solutions we can take into account all the stages of a planary transistor formation.

Źródło:

Acta Physica Polonica A; 1998, 93, 5-6; 731-735
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 64.

Tytuł:

FINANCIAL MARKETS DIFFUSION PATTERNS. THE CASE OF MEXICAN INVESTMENT FUNDS

Autorzy:

Marszk, Adam
Lechman, Ewa
Kaur, Harleen

Powiązania:

https://bibliotekanauki.pl/articles/517407.pdf

Data publikacji:

2017

Wydawca:

Instytut Badań Gospodarczych

Tematy:

exchange traded funds
mutual funds
diffusion models
financial innovation
Mexico

Opis:

Research background: Exchange traded funds (ETFs) are one of the most influential financial innovations, reshaping the investment funds market in many countries, including Mexico. Due to their similar investment objectives, ETFs are considered substitutes for mutual funds. Purpose of the article: The aim of the article is to provide an indepth insight into the issues associated with the development of financial markets in Mexico over the period 2002-2012, putting special emphasis on the development patterns of ETFs. Methods: First we use descriptive statistics to unveil basic changes and trends in the Mexican investment funds (ETFs and mutual funds). Then we use a category of the innovation diffusion models, i.e. logistic growth models, in order to explore the key development patterns. Data sources and methodological framework are presented in the second section of the article, with a detailed description of the innovation diffusion models applied in the research (based on 3-parametric logistic curve). The sum of assets under management of ETFs and mutual funds is considered as the size of the total investment funds market. Findings & Value added: Empirical findings indicate a significant development of the ETF market, both in terms of assets under management and market share. According to the presented estimations, Mexican ETF market development can be described with the logistic growth models, and three characteristic phases of the logistic curve were clearly observable. The predicted ETF market development patterns point towards a further increase of the market share of ETFs over the next 3-5 years, yet the probability of exceeding the level of ca. 20-30% seems low.

Źródło:

Equilibrium. Quarterly Journal of Economics and Economic Policy; 2017, 12, 1; 83-100
1689-765X
2353-3293

Pojawia się w:

Equilibrium. Quarterly Journal of Economics and Economic Policy

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 65.

Tytuł:

Simultaneous measurement of Cr, Mn and Fe diffusion in chromium-manganese steels

Autorzy:

Dudała, J.
Gilewicz-Wolter, J.
Stęgowski, Z.

Powiązania:

https://bibliotekanauki.pl/articles/148882.pdf

Data publikacji:

2005

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

radiotracers
diffusion
steel
spectrum
artificial neural networks

Opis:

The paper presents an application of multitracer method to diffusion measurement in Cr-Mn steels. Radioisotope tracers of chromium 51Cr, manganese 54Mn and iron 59Fe were used simultaneously in the diffusion process. Measurements of gamma-ray spectra and the proper analysis enabled evaluation of concentration distribution for each tracer. As a new tool, artificial neural networks (ANN) method was used for analysis of spectra. The proper solution of the diffusion model was applied to the experimental tracers' distribution data and diffusion coefficients were determined.

Źródło:

Nukleonika; 2005, 50, 2; 67-71
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 66.

Tytuł:

The usefulness and limitations of diffusion tensor imaging – a review study

Autorzy:

Kierońska, Sara
Słoniewski, Paweł

Powiązania:

https://bibliotekanauki.pl/articles/895759.pdf

Data publikacji:

2020-01-09

Wydawca:

Gdański Uniwersytet Medyczny

Tematy:

Diffusion Tensor Imaging
tractography
corticospinal tract
arcuate fasciculus
frontal aslant tract

Opis:

Diffusion tensor tractography (DTI) has been used for planning of a brain pathology surgeries. Knowledge about the distances between neural tracts and brain tumours is believed to increase the patient safety and implies the extent of resection. The aim of the study was to demonstrate the contemporary possibilities and the clinical usefulness of DTI. Following the explanation of the technical basics of DTI, we presented the drawbacks and limitations of this visualisation technique. The most commonly outlined tracts are corticospinal tract (CST), arcuate fasciculus (AF) and frontal aslant tract (FAT). Tumour located in frontal, parietal or temporal lobe can affect the course of the CST. There are two basic possibilities to visualise CST: deterministic and probabilistic. The usefulness of DTI seems limited in imaging the neoplasms of either frontal or temporal region causing aphasia, which infiltrate the AF or the FAT. This limitation is probably related to divergent and patient-specific location of functional speech areas. Acquisition disturbances, ill-defined mathematical algorithms, surgery-related brain shift and defining wrong non-functional brain area are the sources of DTI inaccuracy, which is limiting its clinical application.

Źródło:

European Journal of Translational and Clinical Medicine; 2019, 2, 2; 43-51
2657-3148
2657-3156

Pojawia się w:

European Journal of Translational and Clinical Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 67.

Tytuł:

Kinetic Monte Carlo study of structural proton diffusion along a one-dimensional path

Autorzy:

Masłowski, T.
Drzewiński, A.
Zubaszewska, M.

Powiązania:

https://bibliotekanauki.pl/articles/122324.pdf

Data publikacji:

2015

Wydawca:

Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej

Tematy:

computational statistical mechanics
diffusion processes
procesy dyfuzyjne

Opis:

We study the structural diffusion coefficient of protons in a chain-like system by the means of KMC simulations. To perform specific calculations, we adopted parameter values in our model that correspond to the benzimidazole crystal. As we have shown, the structural diffusion follows the Arrhenius-like thermal dependence with an effective activation energy of 2.01 eV.

Źródło:

Journal of Applied Mathematics and Computational Mechanics; 2015, 14, 3; 59-64
2299-9965

Pojawia się w:

Journal of Applied Mathematics and Computational Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 68.

Tytuł:

Diffusion Kinetics of Binary Ti-Ni Shape Memory Alloys

Autorzy:

Ucar, N.
Dogan, S.
Ozdemir, A.
Karakas, S.
Calik, A.

Powiązania:

https://bibliotekanauki.pl/articles/1031122.pdf

Data publikacji:

2017-09

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

boriding
shape memory alloys
microhardness
boride layer
diffusion

Opis:

In this work, the boriding of binary Ti-Ni shape memory alloys was carried out in a solid medium at 1173 and 1273 K for 2, 4, and 8 h using the powder pack method with Ekabor-Ni powders. The boride layer was characterized by optical microscopy and scanning electron microscopy. The obtained results show that boride layer thickness increases with the increasing boriding temperature and time. Depending on temperature and boride layer thickness, the diffusion process is thermally activated, with the mean value of the activation energy being close to 67 kJ/mol.

Źródło:

Acta Physica Polonica A; 2017, 132, 3; 524-526
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 69.

Tytuł:

Diffusion of Cd(II), Pb(II) and Zn(II) on calcium alginate beads

Autorzy:

Kwiatkowska-Marks, Sylwia
Miłek, Justyna
Trawczyńska, Ilona

Powiązania:

https://bibliotekanauki.pl/articles/297886.pdf

Data publikacji:

2019

Wydawca:

Uniwersytet Warmińsko-Mazurski w Olsztynie

Tematy:

effective diffusion
alginate beads
cadmium
lead
zinc

Opis:

Effective diffusion coefficients (De) for different heavy-metal salts: Cd, Pb, Zn in calcium alginate beads were determined. Their values depend on the metal type, anion from the metal salt, and the alginate content in the beads. The results of calculations indicate a decrease in the values of De, caused by an increase in the alginate content in the alginate sorbent beads. This is in agreement with the mechanism of the diffusion process taking place in porous carriers. Experimental data were found to be in good agreement with the mathematical model, as indicated by high values of the correlation coefficient.

Źródło:

Technical Sciences / University of Warmia and Mazury in Olsztyn; 2019, 22(1); 19-34
1505-4675
2083-4527

Pojawia się w:

Technical Sciences / University of Warmia and Mazury in Olsztyn

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 70.

Tytuł:

A comparison of oxygen diffusion rates in sand moistened with water or PEG 20000 solution

Autorzy:

Hiller, S.
Dexter, A.R.

Powiązania:

https://bibliotekanauki.pl/articles/24419.pdf

Data publikacji:

1997

Wydawca:

Polska Akademia Nauk. Instytut Agrofizyki PAN

Tematy:

sand
air
oxygen diffusion
polyethylene glycol
water

Źródło:

International Agrophysics; 1997, 11, 3
0236-8722

Pojawia się w:

International Agrophysics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 71.

Tytuł:

Globalna fala protestu i rewolucji: przyczyny, cele, dyfuzja
The global wave of protest and revolution: causes, goals, diffusion

Autorzy:

Chodak, Jarosław

Powiązania:

https://bibliotekanauki.pl/articles/561448.pdf

Data publikacji:

2016-12-31

Wydawca:

Collegium Civitas

Tematy:

protest
rewolucja
dyfuzja
mobilizacja
revolution
diffusion
mobilization

Opis:

Globalną falę protestów i rewolucji, której punktem kulminacyjnym był rok 2011, można uznać za zjawisko o wielorakich konsekwencjach geopolitycznych, społecznych i kulturowych. Celem artykułu jest analiza głównych przyczyn mobilizacji, celów protestujących oraz mechanizmów globalnego rozprzestrzeniania się podobnych repertuarów kontestacji, ram interpretacyjnych, symboli, i sloganów. Refleksja zawarta w artykule obejmuje elementy analizy porównawczej, której celem jest uchwycenie głównych mechanizmów przyczynowych. W procesie wyjaśniającym odwołuję się do koncepcji dyfuzji, kultury światowej oraz analizy ramowej. Efektem są generalizacje historyczne na temat głównych mechanizmów dynamiki współczesnej mobilizacji globalnej.
Global wave of protests and revolutions, which climaxed in 2011, can be considered as the phenomenon of multiple geopolitical, social and cultural consequences. The purpose of the article is to analyze the main causes of the mobilization, goals of the protesters and mechanisms of the global spread of similar repertoires of contestation, interpretative frames, symbols and slogans. Reflection presented in the paper includes elements of the comparative analysis, the aim of which is to capture the major causal mechanisms. I referred to the concept of the diffusion, the world culture and frame analysis. Historical generalizations about the main mechanisms of the dynamics of contemporary global mobilization is the result.

Źródło:

Zoon Politikon; 2016, 7; 35-56
2543-408X

Pojawia się w:

Zoon Politikon

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 72.

Tytuł:

Global existence and blow up of solutions for a completely coupled Fujita type system of reaction-diffusion equations

Autorzy:

Rencławowicz, Joanna

Powiązania:

https://bibliotekanauki.pl/articles/1338982.pdf

Data publikacji:

1998

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Tematy:

reaction-diffusion system
global existence
blow up

Opis:

We examine the parabolic system of three equations $u_t$ - Δu = $v^p$, $v_t$ - Δv = $w^q$, $w_t$ - Δw = $u^r$, x ∈ $ℝ^N$, t > 0 with p, q, r positive numbers, N ≥ 1, and nonnegative, bounded continuous initial values. We obtain global existence and blow up unconditionally (that is, for any initial data). We prove that if pqr ≤ 1 then any solution is global; when pqr > 1 and max(α,β,γ) ≥ N/2 (α, β, γ are defined in terms of p, q, r) then every nontrivial solution exhibits a finite blow up time.

Źródło:

Applicationes Mathematicae; 1998-1999, 25, 3; 313-326
1233-7234

Pojawia się w:

Applicationes Mathematicae

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 73.

Tytuł:

Bayesian DEJD Model and Detection of Asymmetry in Jump Sizes

Autorzy:

Kostrzewski, Maciej

Powiązania:

https://bibliotekanauki.pl/articles/2076552.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

double exponential jump diffusion model
Kou model
Bernoulli jump-diffusion model
MCMC methods
latent variables

Opis:

News might trigger jump arrivals in financial time series. The "bad" news and "good" news seem to have distinct impact. In the research, a double exponential jump distribution is applied to model downward and upward jumps. Bayesian double exponential jump-diffusion model is proposed. Theorems stated in the paper enable estimation of the model’s parameters, detection of jumps and analysis of jump frequency. The methodology, founded upon the idea of latent variables, is illustrated with simulated data.

Źródło:

Central European Journal of Economic Modelling and Econometrics; 2015, 1; 43-70
2080-0886
2080-119X

Pojawia się w:

Central European Journal of Economic Modelling and Econometrics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 74.

Tytuł:

The Cauchy problem for the time-fractional advection diffusion equation in a layer

Autorzy:

Povstenko, Y.
Klekot, J.

Powiązania:

https://bibliotekanauki.pl/articles/298257.pdf

Data publikacji:

2016

Wydawca:

Uniwersytet Warmińsko-Mazurski w Olsztynie

Tematy:

porous medium
non-Fickian diffusion
fractional calculus
Mittag-Leffler function

Opis:

The time-fractional advection-diffusion equation with the Caputo time derivative is studied in a layer. The fundamental solution to the Cauchy problem is obtained using the integral transform technique. The logarithmicsingularity term is separated from the solution. Expressions amenable for numerical treatment are obtained. The numerical results are illustrated graphically.

Źródło:

Technical Sciences / University of Warmia and Mazury in Olsztyn; 2016, 19(3); 231-244
1505-4675
2083-4527

Pojawia się w:

Technical Sciences / University of Warmia and Mazury in Olsztyn

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 75.

Tytuł:

Fundamental solution to the Cauchy problem for the time-fractional advection-diffusion equation

Autorzy:

Povstenko, Y.
Klekot, J.

Powiązania:

https://bibliotekanauki.pl/articles/122910.pdf

Data publikacji:

2014

Wydawca:

Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej

Tematy:

Cauchy problem
Mittag-Leffler function
time-fractional diffusion-wave equation

Opis:

The one-dimensional time-fractional advection-diffusion equation with the Caputo time derivative is considered. The fundamental solution to the Cauchy problem is obtained using the integral transform technique. The numerical results are illustrated graphically.

Źródło:

Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 1; 95-102
2299-9965

Pojawia się w:

Journal of Applied Mathematics and Computational Mechanics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 76.

Tytuł:

Microstructure Study of Diffusion Bonding of Centrifuged Structural Steel-Bronze

Autorzy:

Soflaei, H.
Vahdat, S. E.

Powiązania:

https://bibliotekanauki.pl/articles/382173.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

centrifugal casting
bearings
microstructure
lubrication
diffusion bonding
line scan
odlewanie odśrodkowe
łożyska
mikrostruktura

Opis:

One of the methods to prevent unsuitable lubrication of moving components of devices and machinery is using bi-metal and three-metal bearings. Centrifugal casting process is one of the manufacturing methods that is used for such bearings. In this study, the purpose is microstructure evaluation of the bonding location and length determination of diffusion bond in structural steel-bronze. A mold made of structural steel with inner diameter of 240mm, length of 300mm and thickness of 10mm was coated by a 6mm film of bronze under centrifugal casting process. At first, a bronze ingot with dimension of 5mm×10mm×20mm is located inside of the hollow cylindrical mold and then the two ends of it will be sealed. During mold rotation with the rate of 800 rpm, two high power flames are used for heating the mold under Ar gas atmosphere to melt the bronze ingot at 1000˚C. After 15minutes, the system is cooled rapidly. Results showed that the diffusion bonding of bronze in structural steel to depth of 1.2μm from the bonding line was obtained. In this bonding, copper element was diffused to 50% of its initial concentration.

Źródło:

Archives of Foundry Engineering; 2016, 16, 2; 99-104
1897-3310
2299-2944

Pojawia się w:

Archives of Foundry Engineering

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 77.

Tytuł:

A study of cerium extraction by TBP and TODGA using a rotating diffusion cell

Autorzy:

Bromley, M. A.
Boxall, C.

Powiązania:

https://bibliotekanauki.pl/articles/148471.pdf

Data publikacji:

2015

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

SACSESS
TBP
TODGA
rotating diffusion cell (RDC)
separation
extraction

Opis:

For the study of the coupled interfacial-mass transfer kinetics of, inter alia, TBP, TODGA, CyMe4-BTBP and CyMe4-BTPhen based solvent extraction processes, a new rotating diffusion cell (RDC) apparatus has been established at Lancaster University. RDC studies of Ce(IV)/TBP and Ce(III)/TODGA extraction systems have been undertaken in order to improve the understanding of the chemical and kinetic processes involved. In each case, an interesting dependency on local hydrodynamics at the solution phase boundary with results suggesting that the organic extractant molecules migrate into the aqueous phase in order to capture Ce.

Źródło:

Nukleonika; 2015, 60, No. 4, part 2; 859-864
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 78.

Tytuł:

Computing Reverberation Time in a 3D Room Model Using a Finite Difference Method Applied for the Diffusion Equation

Autorzy:

Kraszewski, J.

Powiązania:

https://bibliotekanauki.pl/articles/177730.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

diffusion method
reverberation time
finite differences method

Opis:

The article presents theoretical values of reverberation times calculated on the basis of the diffusion equation for three room models: flat, cubic, and long. The article shows that not only the average absorp- tion coefficient, but also location of the absorbent material, as well as the place where the time is counted have an impact on the reverberation time, calculated on the basis of the diffusion equation. Despite that, the diffusion model is based on statistical assumptions. The primary goal of the article was to show that the model has geometrical features.

Źródło:

Archives of Acoustics; 2012, 37, 2; 171-180
0137-5075

Pojawia się w:

Archives of Acoustics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 79.

Tytuł:

Characterisctics of aeration properties of Orthic Luvisol from Poland under different land use

Autorzy:

Stepniewski, W.
Stepniewska, Z.
Przywara, G.
Brzezinska, M.
Wlodarczyk, T.

Powiązania:

https://bibliotekanauki.pl/articles/24066.pdf

Data publikacji:

2000

Wydawca:

Polska Akademia Nauk. Instytut Agrofizyki PAN

Tematy:

catalase activity
soil aeration
Polska
aeration
oxygen diffusion rate
oxygen diffusion coefficient
gas diffusion coefficient
redox potential
dehydrogenase activity
aeration parameter
soil moisture

Źródło:

International Agrophysics; 2000, 14, 4
0236-8722

Pojawia się w:

International Agrophysics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 80.

Tytuł:

Stabilization of solutions of a reaction-diffusion equation

Autorzy:

Fila, Marek

Powiązania:

https://bibliotekanauki.pl/articles/719561.pdf

Data publikacji:

1987

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Źródło:

Banach Center Publications; 1987, 19, 1; 89-93
0137-6934

Pojawia się w:

Banach Center Publications

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 81.

Tytuł:

On the numerical solutions of convection-diffusion equations

Autorzy:

Axelsson, O.

Powiązania:

https://bibliotekanauki.pl/articles/720813.pdf

Data publikacji:

1984

Wydawca:

Polska Akademia Nauk. Instytut Matematyczny PAN

Źródło:

Banach Center Publications; 1984, 13, 1; 165-184
0137-6934

Pojawia się w:

Banach Center Publications

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 82.

Tytuł:

Interest rate models

Autorzy:

Palczewski, Andrzej

Powiązania:

https://bibliotekanauki.pl/articles/748527.pdf

Data publikacji:

2002

Wydawca:

Polskie Towarzystwo Matematyczne

Tematy:

Finance, portfolios, investment
Diffusion processes

Opis:

.
This is a well-written survey paper on post-Heath-Jarrow-Morton interest rate models. The bond pricing and term structure are based on time-dependent continuous-time diffusions, and the main particular cases, including LIBOR and SWAP, are studied in detail.

Źródło:

Mathematica Applicanda; 2002, 30, 44/03
1730-2668
2299-4009

Pojawia się w:

Mathematica Applicanda

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 83.

Tytuł:

Approximated boundary conditions of the equation of diffusion

Autorzy:

Zima, P.

Powiązania:

https://bibliotekanauki.pl/articles/241388.pdf

Data publikacji:

2002

Wydawca:

Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN

Opis:

The paper focuses on boundary conditions in mathematical physics equations. These equations describe the processes of pollutants' migration. The emphasis is put on the influence of boundary conditions' approximation on the solution of one-dimensional advection-dispersion equation. Analytical and numerical solutions were used as a basis for the theoretical consideration. The research included the following methods: `distant boundary' method, rejection of diffusion flux in the boundary profile, rejection of `the near field' and solution of mass or energy balance equation. The research afforded possibilities for quantitative and qualitative identification of the influence of boundary conditions' approximation methods on the equation solution inside domain. The derived formulas made it possible to estimate the margin of error introduced by the simplified method. The formulas were presented in the form of nomograms.

Źródło:

Archives of Hydro-Engineering and Environmental Mechanics; 2002, 49, 2; 71-95
1231-3726

Pojawia się w:

Archives of Hydro-Engineering and Environmental Mechanics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 84.

Tytuł:

The studies of scale surface produced on outer diffusion layers

Autorzy:

Augustyn-Pieniążek, J.
Zapała, R.

Powiązania:

https://bibliotekanauki.pl/articles/379615.pdf

Data publikacji:

2011

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

diffusion aluminising
high temperature corrosion
scale morphology
dyfuzja aluminiowa
korozja wysokotemperaturowa
morfologia zgorzeliny

Opis:

In this study at attempt was made to examine the scale formed on ferritic-austenitic duplex type steel subjected to previous thermo-chemical treatment. The treatment consisted in diffusion aluminising in a metallising mixture composed of Fe-Al powder. As an activator, ammonium chloride (NH₄Cl) added in an amount of 2 wt.% was used. Then, both the base material and samples with the diffusion-deposited surface layers were oxidised at 1000°C in the air. Thus formed scales were identified by light microscopy, SEM and X-ray phase analysis. The aim of the oxidation tests carried out under isothermal conditions was to compare the scale morphology when obtained on untreated substrate material and on the surface layers rich in aluminium.

Źródło:

Archives of Foundry Engineering; 2011, 11, 2 spec.; 5-8
1897-3310
2299-2944

Pojawia się w:

Archives of Foundry Engineering

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 85.

Tytuł:

On the application of the forward and backward diffusion scheme for image enhancement

Autorzy:

Smolka, B.

Powiązania:

https://bibliotekanauki.pl/articles/332900.pdf

Data publikacji:

2002

Wydawca:

Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych

Tematy:

poprawa jakości obrazu
redukcja szumów
anizotropowa dyfuzja
image enhancement
noise reduction
anisotropic diffusion

Opis:

In this paper a novel approach to the problem of edge preserving smoothing is proposed and evaluated. The new algorithm is based on the combined forward and backward anisotropic diffusion with incorporated time dependent cooling process. This method is able to efficiently remove image noise, while preserving and enhancing its edges.

Źródło:

Journal of Medical Informatics & Technologies; 2002, 3; MI51-60
1642-6037

Pojawia się w:

Journal of Medical Informatics & Technologies

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 86.

Tytuł:

Development of the Jewish urban settlement in Israel in view of the theory of the innovation diffusion

Autorzy:

Mularczyk, Mirosław
Mikulska, Małgorzata

Powiązania:

https://bibliotekanauki.pl/articles/2029401.pdf

Data publikacji:

2004-06-01

Wydawca:

Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych

Tematy:

Jewish urban settlement
theory of innovation diffusion

Opis:

Presentation of the current state and development tendencies of Jewish urban settlement in Israel against the innovation diffusion theory. Analysis of the growth tempo of the number of cities in Israel allows to claim that urban Jewish settlement network develops in accordance with the innovation diffusion model. Assuming that the theory fits the urban settlement development pattern on the surveyed territories, the directions taken by the impulses sent by innovation sources have been determined based on the corridor settlement development theory. The hypothesis has been verified against the factors influencing spatial development directions of the Jewish urban settlement using a dynamic (synchronic-comparative) diffusion process simulation model, built with the Monte Carlo method. The conducted analyses and procedures verifying the model distribution of Jewish settlement in Israeli cities in 1948, 1967 and 1992 allowed to conclude that the highest stochastic concordance between the model accounting for the innovation diffusion theory elements, and the real distribution of Jewish settlement cities holds for 1948 and 1967. According to the diffusion innovation theory, these years correspond to the colonisation stage. The model diversifies from reality for late 1967, when network densification process was coming to an end and city competition stage was starting. Despite statistical validity of the hypotheses, the results show that besides the analysed factors influencing the development of Jewish urban settlement, other variables, not accounted for in the model, are also significantly influential.

Źródło:

Miscellanea Geographica. Regional Studies on Development; 2004, 11; 229-240
0867-6046
2084-6118

Pojawia się w:

Miscellanea Geographica. Regional Studies on Development

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 87.

Tytuł:

Solution of linear and nonlinear diffusion problems via stochastic differential equations

Autorzy:

Bargieł, M.
Tory, E. M.

Powiązania:

https://bibliotekanauki.pl/articles/305261.pdf

Data publikacji:

2015

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

nonlinear diffusion
stochastic differential equations
Wiener process
Itô process
Kolmogorov backward equation

Opis:

The equation for nonlinear diffusion can be rearranged to a form that immediately leads to its stochastic analog. The latter contains a drift term that is absent when the diffusion coefficient is constant. The dependence of this coefficient on concentration (or temperature) is handled by generating many paths in parallel and approximating the derivative of concentration with respect to distance by the central difference. This method works for one-dimensional diffusion problems with finite or infinite boundaries and for diffusion in cylindrical or spherical shells. By mimicking the movements of molecules, the stochastic approach provides a deeper insight into the physical process. The parallel version of our algorithm is very efficient. The 99% confidence limits for the stochastic solution enclose the analytical solution so tightly that they cannot be shown graphically. This indicates that there is no systematic difference in the results for the two methods. Finally, we present a direct derivation of the stochastic method for cylindrical and spherical shells.

Źródło:

Computer Science; 2015, 16 (4); 415-428
1508-2806
2300-7036

Pojawia się w:

Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 88.

Tytuł:

Phenomenological and numerical issues concerning dynamics of nonisobaric multicomponent diffusion of gases in macroporous media

Autorzy:

Bizon, Katarzyna
Tabiś, Bolesław

Powiązania:

https://bibliotekanauki.pl/articles/2086815.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

multicomponent diffusion
porous media
dynamics
dyfuzja wieloskładnikowa
porowate media
dynamika

Opis:

The homogeneity of an immiscible liquid–liquid system was investigated in a baffled vessel agitated by a Rushton turbine. The dispersion homogeneity was analyzed by comparing Sauter mean diameters and drop size distribution (DSD) determined in different measured regions for various impeller speeds. The sizes of droplets were obtained by the in-situ measurement technique and by the Image Analysis (IA) method. Dispersion kinetics was successfully fitted with Hong and Lee (1983) model. The effect of intermittency turbulence on drop size reported by Bałdyga and Podgórska (1998) was analyzed and the multifractal exponent was evaluated.

Źródło:

Chemical and Process Engineering; 2021, 42, 3; 223--234
0208-6425
2300-1925

Pojawia się w:

Chemical and Process Engineering

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 89.

Tytuł:

Diffusion approximation of recurrent schemes for financial markets, with application to the Ornstein-Uhlenbeck process

Autorzy:

Mishura, Y.

Powiązania:

https://bibliotekanauki.pl/articles/952778.pdf

Data publikacji:

2015

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

diffusion approximation
semimartingale
recurrent scheme
financial market
multiplicative scheme
Ornstein-Uhlenbeck process

Opis:

We adapt the general conditions of the weak convergence for the sequence of processes with discrete time to the diffusion process towards the weak convergence for the discrete-time models of a financial market to the continuous-time diffusion model. These results generalize a classical scheme of the weak convergence for discrete-time markets to the Black-Scholes model. We give an explicit and direct method of approximation by a recurrent scheme. As an example, an Ornstein-Uhlenbeck process is considered as a limit model.

Źródło:

Opuscula Mathematica; 2015, 35, 1; 99-116
1232-9274
2300-6919

Pojawia się w:

Opuscula Mathematica

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 90.

Tytuł:

On the structure of the diffusion distance induced by the fractional dyadic Laplacian

Autorzy:

Acosta, María Florencia
Aimar, Hugo
Gómez, Ivana
Morana, Federico

Powiązania:

https://bibliotekanauki.pl/articles/29519486.pdf

Data publikacji:

2024

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

diffusion metrics
dyadic diffusion

Opis:

In this note we explore the structure of the diffusion metric of Coifman-Lafon determined by fractional dyadic Laplacians. The main result is that, for each t > 0, the diffusion metric is a function of the dyadic distance, given in $ \mathbb{R}^+ $ by δ(x, y) = inf {|I| : I is a dyadic interval containing x and y}. Even if these functions of δ are not equivalent to δ, the families of balls are the same, to wit, the dyadic intervals.

Źródło:

Opuscula Mathematica; 2024, 44, 2; 157-165
1232-9274
2300-6919

Pojawia się w:

Opuscula Mathematica

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 91.

Tytuł:

Dyfuzja innowacji i determinanty jej sukcesu
Diffusion of innovations and determinants of its success

Autorzy:

Nowakowski, M.
Nowakowska, B.

Powiązania:

https://bibliotekanauki.pl/articles/325408.pdf

Data publikacji:

2017

Wydawca:

Politechnika Śląska. Wydawnictwo Politechniki Śląskiej

Tematy:

innowacje
dyfuzja innowacji
transfer wiedzy
innovation
diffusion of innovations
knowledge transfer

Opis:

Celem pracy jest analiza literatury dotyczącej procesu dyfuzji innowacji, a w szczególności odpowiedź na pytanie, jakie czynniki wpływają na sukces lub porażkę upowszechnienia nowych, innowacyjnych rozwiązań. W niniejszym artykule autorzy podejmują się również próby zidentyfikowania luk badawczych występujących w literaturze.
The aim of the study is to analyze the literature on the process of diffusion of innovation, and in particular providing an answer to the question of which factors influence the success or failure of dissemination of new, innovative solutions. In this article the authors also attempt to identify research gaps in existing literature.

Źródło:

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska; 2017, 100; 353-364
1641-3466

Pojawia się w:

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 92.

Tytuł:

Oscillation of time fractional vector diffusion-wave equation with fractional damping

Autorzy:

Ramesh, R.
Harikrishnan, S.
Nieto, J. J.
Prakash, P.

Powiązania:

https://bibliotekanauki.pl/articles/255843.pdf

Data publikacji:

2020

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

fractional diffusion-wave equation H-oscillation
vector differential equation

Opis:

In this paper, sufficient conditions for H-oscillation of solutions of a time fractional vector diffusion-wave equation with forced and fractional damping terms subject to the Neumann boundary condition are established by employing certain fractional differential inequality, where H is a unit vector in Rn. The examples are given to illustrate the main results.

Źródło:

Opuscula Mathematica; 2020, 40, 2; 291-305
1232-9274
2300-6919

Pojawia się w:

Opuscula Mathematica

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 93.

Tytuł:

Influence of diffusion and impedence parameters on wave propagation in thermoelastic medium

Autorzy:

Kaushal, Sachin
Kumar, Rajneesh
Parmar, Kulwinder

Powiązania:

https://bibliotekanauki.pl/articles/2174177.pdf

Data publikacji:

2021

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

fala płaska
dyfuzja
impedancja
plane wave
amplitude ratios
diffusion
impedance parameters

Opis:

The aim of the present paper is to study the impact of diffusion and impedance parameters on the propagation of plane waves in a thermoelastic medium for Green and Lindsay theory (G-L) and the Coupled theory (C-T) of thermoelasticity. Results are demonstrated for impedance boundary conditions and the amplitude ratios of various reflected waves against the angle of incidence are calculated numerically. The characteristics of diffusion, relaxation time and impedence parameter on amplitude ratios have been depicted graphically. Some cases of interest are also derived from the present investigation.

Źródło:

International Journal of Applied Mechanics and Engineering; 2021, 26, 4; 99--112
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 94.

Tytuł:

Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder

Autorzy:

Lee, M.-W.
Bae, K.-H.
Lee, S.-R.
Kim, H.-J.
Jang, T.-S.

Powiązania:

https://bibliotekanauki.pl/articles/353351.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

Nd-Fe-B sintered magnets
grain boundary diffusion process
low melting point element
DyCo alloy-powder diffusion

Opis:

We investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1st post annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd₂ Fe₁₄ B and grain boundary phases covering Nd₂ Fe₁₄ B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)₂Fe₁₄B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd₂O₃ phase.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 2B; 1263-1266
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 95.

Tytuł:

Exact difference schemes and schemes of higher order of approximation for convection-diffusion equation. I

Autorzy:

Lapinska-Chrzczonowicz, M.
Matus, P.

Powiązania:

https://bibliotekanauki.pl/articles/106186.pdf

Data publikacji:

2013

Wydawca:

Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej

Tematy:

convection-diffusion equation
initial-boundary value problem
traveling wave
EDS

Opis:

The initial-boundary value problem for a convection-diffusion equation [formula] is considered. The difference scheme, approximating this problem, is constructed. It is shown that for traveling wave solutions the scheme is exact (EDS). The monotonicity of the scheme is also taken into consideration. Presented numerical experiments illustrate the theoretical results investigated in the paper.

Źródło:

Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2013, 13, 1; 37-51
1732-1360
2083-3628

Pojawia się w:

Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 96.

Tytuł:

Home as a mixture of spaces during the COVID-19 pandemic: The case of migrant families in Poland

Autorzy:

Popyk, Anzhela

Powiązania:

https://bibliotekanauki.pl/articles/2053526.pdf

Data publikacji:

2021-09-28

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

home
social diffusion
diffusion of spaces
migrant family
COVID-19

Opis:

The spread of the coronavirus has led to significant modifications in the majority of social and private institutions. For most families, home is now the location of many activities that are usually kept separate, such as work, school, entertainment, and socialising. Migrant families, for whom the school was the primary place for socialising, were forced to “host” school at home. As a result, migrant families’ homes have been reconstructed from a private household and intimate dwelling place into a mixture of spaces. This paper applies the theory of social diffusion developed by Dodd and Winthrop, and the concept of social solvation designed by Sarnowska et al., to study the diffusion of places at the time of lockdown. The data are derived from a qualitative study of migrant families in Poland during the school shutdown. This study investigates how the mixture of various places within the home has affected the lives of family members.

Źródło:

Kultura i Społeczeństwo; 2021, 65, 3; 27-45
2300-195X

Pojawia się w:

Kultura i Społeczeństwo

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 97.

Tytuł:

Properties of a Meshless Simulation Method of Diffusion from a Finite Source
Własności bezsiatkowej metody symulacji dyfuzji ze źródła skończonego

Autorzy:

Dawidowicz, T.

Powiązania:

https://bibliotekanauki.pl/articles/305907.pdf

Data publikacji:

2011

Wydawca:

Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego

Tematy:

metoda bezsiatkowa
dyfuzja
symulacja
meshless method
diffusion
simulation

Opis:

The paper presents an analysis of the properties of a numerical algorithm of a diffusion simulation from a finite source based on a meshless numerical method. The simulation time dependencies and simulation errors have been presented. The range of parameters were indicated for which the method achieves physical results.
W pracy przedstawiono analizę właściwości algorytmu numerycznego symulacji dyfuzji ze źródła skończonego opartego o bezsiatkową metodę numeryczną. Wykazano zależności czasowe symulacji oraz przedstawiono błędy symulacji. Wskazano zakres parametrów, dla których metoda uzyskuje wyniki fizyczne.

Źródło:

Biuletyn Instytutu Systemów Informatycznych; 2011, 8; 25-33
1508-4183

Pojawia się w:

Biuletyn Instytutu Systemów Informatycznych

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 98.

Tytuł:

GENDERED FAMILY PRACTICES AND CULTURAL DIFFUSION IN BINATIONAL COUPLES OF POLISH MIGRANT WOMEN

Autorzy:

Buler, Marta
Pustułka, Paula

Powiązania:

https://bibliotekanauki.pl/articles/579984.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

BINATIONAL MARRIAGES
DUAL-ETHNICITY COUPLES
POLISH MIGRATION
FAMILY PRACTICES
GENDER ORDERS
CULTURAL DIFFUSION

Opis:

The article discusses family practices and gender relations in the interethnic couples of Polish women having foreign partners. While the theoretical framework engages with conceptualizations of family practice, binational coupledom, cultural diffusion and gender orders, the mix-methods methodological approach combines cases from three qualitative and thematically-linked research projects on Polish migration across three EU destination countries. We argue that spousal attitudes to gender orders shape the degree of cultural diffusion in interethnic couples formed by Polish women in Western Europe. In addition, we propose that gender orders of the spouses must not align with the ethnic belonging, but rather illuminate the pre-existing preferences for a traditional or egalitarian model. More broadly, we observe that women remain the key agents of sustaining or rejecting the Polish heritage and practices in the everyday life. In other words, the women determine the degree and shape of the intra-family cultural diffusion.

Źródło:

Studia Migracyjne - Przegląd Polonijny; 2017, 43, 4 (166); 37-59
2081-4488
2544-4972

Pojawia się w:

Studia Migracyjne - Przegląd Polonijny

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 99.

Tytuł:

New Technologies Adoption and Diffusion Patterns in Developing Countries. An Empirical Study for the Period 2000-2011

Autorzy:

Lechman, Ewa

Powiązania:

https://bibliotekanauki.pl/articles/517122.pdf

Data publikacji:

2013

Wydawca:

Instytut Badań Gospodarczych

Tematy:

Information and Communication Technologies
adoption patterns
technology diffusion
S-shaped curve

Opis:

In recent years, enormous changes are noted worldwide during broad adoption of Information and Communication Technologies (ICT). These unique technologies – often perceived as economic development incentives – have a great ability to spread at high pace and low cost in countries all over the world, bringing people opportunities to contribute to economic development and growth. New Tech-nologies play a special role in developing countries, where their in-country adoption lies in the centre of development strategies. ICT are treated as tools which bring people access to information, education and knowledge, offering unlimited possibilities for wealth-creation. The paper, purely empirical in nature, reports on the pace of adoption of new Information and Communication Technologies in developing countries, and – additionally – investigates country-specific ICT diffusion patterns. We expect to uncover the S-shape curve in the diffusion process in most of developing countries, as well as in the whole country sample. For the analysis purposes, we apply all counties which – according to the World Bank nomenclature – are classified as low-income and lower-middle-income econ-omies. Our sample covers 46 countries (upper-middle-income and high-income economies are excluded from the study purposefully) which are classified as devel-oping economies. The time framework is set for the period of 2000-2011. All data necessary for the analysis are derived from World Telecommunication/ICT Indica-tors Database 2012 (16th edition).

Źródło:

Equilibrium. Quarterly Journal of Economics and Economic Policy; 2013, 8, 4; 79-106
1689-765X
2353-3293

Pojawia się w:

Equilibrium. Quarterly Journal of Economics and Economic Policy

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 100.

Tytuł:

A numerical scheme for time-fractional fourth-order reaction-diffusion model

Autorzy:

Koç, Dilara Altan

Powiązania:

https://bibliotekanauki.pl/articles/24201500.pdf

Data publikacji:

2023

Wydawca:

Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej

Tematy:

implicit finite difference method
fractional calculus
diffusion equation
niejawna metoda różnic skończonych
rachunek ułamkowy
równanie dyfuzji

Opis:

In fractional calculus, the fractional differential equation is physically and theoretically important. In this article an efficient numerical process has been developed. Numerical solutions of the time fractional fourth order reaction diffusion equation in the sense of Caputo derivative is obtained by using the implicit method, which is a finite difference method and is developed by increasing the number of iterations. The advantage of the implicit difference scheme is unconditionally stable. The stability analysis and convergency have been proven. A numerical example has been presented, and the validity of the method is supported by tables and graphics.

Źródło:

Journal of Applied Mathematics and Computational Mechanics; 2023, 22, 2; 15--25
2299-9965

Pojawia się w:

Journal of Applied Mathematics and Computational Mechanics

Dostawca treści:

Biblioteka Nauki

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