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Wyszukujesz frazę "Diffusion" wg kryterium: Wszystkie pola


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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
Tytuł:
A general study of fundamental solutions in aniotropicthermoelastic media with mass diffusion and voids
Autorzy:
Chawla, Vijay
Kamboj, Deepmala
Powiązania:
https://bibliotekanauki.pl/articles/1839675.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
termosprężystość
dyfuzja masy
źródło ciepła
general solution
fundamental solution
thermoelastic
voids
mass diffusion
Opis:
The present paper deals with the study of a fundamental solution in transversely isotropic thermoelastic media with mass diffusion and voids. For this purpose, a two-dimensional general solution in transversely isotropic thermoelastic media with mass diffusion and voids is derived first. On the basis of the obtained general solution, the fundamental solution for a steady point heat source on the surface of a semi-infinite transversely isotropic thermoelastic material with mass diffusion and voids is derived by nine newly introduced harmonic functions. The components of displacement, stress, temperature distribution, mass concentration and voids are expressed in terms of elementary functions and are convenient to use. From the present investigation, some special cases of interest are also deduced and compared with the previous results obtained, which prove the correctness of the present result.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 4; 22-41
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specification of the process of chloride extraction from reinforced concrete based on the inverse task of the diffusion equation
Autorzy:
Alsabry, A.
Zybura, A.
Powiązania:
https://bibliotekanauki.pl/articles/265298.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
korozja
dyfuzja
ekstrakcja
corrosion
diffusion
inverse task
removing chlorides
extraction
Opis:
When the structure of reinforcement is in danger of chloride corrosion it is possible to prevent this disadvantageous phenomenon through exposing the cover to the influence of an electric field. The forces of an electric field considerably reduce chloride ions in pore liquid in concrete, which helps to rebuild a passive layer on the surface of the reinforcement and stops corrosion. The process of removing chlorides can be described with multi-component diffusion equations. However, an essential parameter of these equations, the diffusion coefficient, can be determined on the basis of an inverse task. Since the solution was achieved for one-dimension flow, the method applied can be confirmed by experimental results and the material parameters of the process can be determined theoretically. Some examples of numerical calculations of the effective electro-diffusion coefficient of chloride ions confirmed the usefulness of the theoretical solution for generalizing experimental results. Moreover, the calculation process of the numerical example provides some practical clues for future experimental research, which could be carried out in close connection with the theoretical solution.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 2; 261-271
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A numerical solution for a class of time fractional diffusion equations with delay
Autorzy:
Pimenov, V. G.
Hendy, A. S.
Powiązania:
https://bibliotekanauki.pl/articles/330624.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fractional diffusion equation
difference scheme
convergence analysis
równanie dyfuzji ułamkowe
schemat różnicowy
analiza zbieżności
Opis:
This paper describes a numerical scheme for a class of fractional diffusion equations with fixed time delay. The study focuses on the uniqueness, convergence and stability of the resulting numerical solution by means of the discrete energy method. The derivation of a linearized difference scheme with convergence order O(τ 2−α + h4) in L ∞-norm is the main purpose of this study. Numerical experiments are carried out to support the obtained theoretical results.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 3; 477-488
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical solutions by EFGM of MHD convective fluid flow past a vertical plate immersed in a porous medium in the presence of cross diffusion effects via biot number and convective boundary condition
Autorzy:
Raju, R. S.
Reddy, B. M.
Rashidi, M. M.
Gorla, R. S. R.
Powiązania:
https://bibliotekanauki.pl/articles/265443.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
thermal diffusion
diffusion thermo
MHD
porous medium
EFGM
dyfuzja termiczna
magnetohydrodynamika
porowatość
Opis:
In this investigation, the numerical results of a mixed convective MHD chemically reacting flow past a vertical plate embedded in a porous medium are presented in the presence of cross diffusion effects and convective boundary condition. Instead of the commonly used conditions of constant surface temperature or constant heat flux, a convective boundary condition is employed which makes this study unique and the results more realistic and practically useful. The momentum, energy, and concentration equations derived as coupled second-order, ordinary differential equations are solved numerically using a highly accurate and thoroughly tested element free Galerkin method (EFGM). The effects of the Soret number, Dufour number, Grashof number for heat and mass transfer, the viscous dissipation parameter, Schmidt number, chemical reaction parameter, permeability parameter and Biot number on the dimensionless velocity, temperature and concentration profiles are presented graphically. In addition, numerical results for the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are discussed through tabular forms. The discussion focuses on the physical interpretation of the results as well as their comparison with the results of previous studies.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 613-636
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MHD and thermal radiation effects on exponentially accelerated isothermal vertical plate with uniform mass diffusion
Autorzy:
Muthucumaraswamy, R.
Visalakshi, V.
Powiązania:
https://bibliotekanauki.pl/articles/265445.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
promieniowanie
izotermiczność
płyta pionowa
dyfuzja masy
pole magnetyczne
radiation
isothermal
vertical plate
mass diffusion
magnetic field
Opis:
Thermal radiation effects on an unsteady free convective flow of a viscous incompressible flow of a past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion in the presence magnetic field are considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature is raised to Tw and the concentration level near the plate is also raised to Cʹw . An exact solution to the dimensionless governing equations is obtained by the Laplace transform method, when the plate is exponentially accelerated with a velocity u= u0 exp(aʹtʹ) in its own plane against gravitational field. The effects of velocity, temperature and concentration fields are studied for different physical parameters such as the magnetic field parameter, thermal radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing magnetic field parameter or radiation parameter. But the trend is just reversed with respect to a or t .
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 599-608
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study on flow past an oscillating plate with variable temperature and uniform mass diffusion under chemical reaction
Autorzy:
Vijayalakshmi, A. R.
Selvajayanthi, M.
Powiązania:
https://bibliotekanauki.pl/articles/955172.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
reakcja chemiczna
wymiana ciepła
dyfuzja masy
chemical reaction
oscillating vertical plate
heat transfer
mass diffusion
Opis:
An numerical study on an unsteady flow past an oscillating semi-infinite vertical plate with variable temperature and uniform mass diffusion under the influence of a first order chemical reaction has been carried out. The dimensionless governing equations are solved by an unconditionally stable and fast converging implicit finite difference scheme. The effects of velocity and temperature for different physical parameters such as the chemical reaction parameter, thermal Grashof number, mass Grashof number and time are analysed. It is observed that due to the presence of first order chemical reaction, the velocity increases during a generative reaction and decreases in a destructive reaction.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 1; 181-193
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of thermal expansion on flow past an inclined accelerated sectional plate with persistent mass diffusion
Autorzy:
Nagarajan, G.
Sundar Raj, M.
Muthucumaraswamy, R.
Powiązania:
https://bibliotekanauki.pl/articles/27312397.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
rozszerzalność cieplna
dyfuzja masy
transformata Laplace'a
thermal expansion
mass diffusion
accelerated
inclined plate
isothermal
Opis:
In this article, we examined the solution of a homogeneously intensified isothermal inclined infinite plate with constant temperature. The plate is elevated to Tw, and the species accumulation is enhanced at a consistent speed. Under appropriate boundary conditions, the non-dimensional guiding formulae are remedied using the Laplace transform procedure. The effect of velocity, temperature, and concentration on various factors, including thermal and mass Grashof numbers, Schmidt numbers, and duration, is discussed. The velocity increases proportionally to the thermal and mass Grashof numbers, but decreases as the inclined angle, Schmidt numbers and time increase.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 4; 105--116
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Global behavior of a multi-group SEIR epidemic model with spatial diffusion in a heterogeneous environment
Autorzy:
Liu, Pengyan
Li, Hong-Xu
Powiązania:
https://bibliotekanauki.pl/articles/2134056.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
global stability
multigroup epidemic model
spatial heterogeneity
spatial diffusion
globalna stabilność
wielogrupowy model epidemii
różnorodność przestrzenna
dyfuzja przestrzenna
Opis:
In this paper, we propose a multi-group SEIR epidemic model with spatial diffusion, where the model parameters are spatially heterogeneous. The positivity and ultimate boundedness of the solution, as well as the existence of a global attractor of the associated solution semiflow, are established. The definition of the basic reproduction number is given by utilizing the next generation operator approach, whereby threshold-type results on the global dynamics in terms of this number are established. That is, when the basic reproduction number is less than one, the disease-free steady state is globally asymptotically stable, while if it is greater than one, uniform persistence of this model is proved. Finally, the feasibility of the main theoretical results is shown with the aid of numerical examples for a model with two groups.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2022, 32, 2; 271--283
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mathematical model for file fragment diffusion and a neural predictor to manage priority queues over BitTorrent
Autorzy:
Napoli, C.
Pappalardo, G.
Tramontana, E.
Powiązania:
https://bibliotekanauki.pl/articles/331212.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
P2P model
neural network
wavelet
diffusion
file sharing
model P2P
sieć neuronowa
falka
dyfuzja
wymiana plików
Opis:
BitTorrent splits the files that are shared on a P2P network into fragments and then spreads these by giving the highest priority to the rarest fragment. We propose a mathematical model that takes into account several factors such as the peer distance, communication delays, and file fragment availability in a future period also by using a neural network module designed to model the behaviour of the peers. The ensemble comprising the proposed mathematical model and a neural network provides a solution for choosing the file fragments that have to be spread first, in order to ensure their continuous availability, taking into account that some peers will disconnect.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2016, 26, 1; 147-160
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On diffusion of chemically reactive species in a convective flow past an inclined plate with variable surface temperature and variable mass diffusion
Autorzy:
Kirubavathi, J. D.
Palani, G.
Powiązania:
https://bibliotekanauki.pl/articles/266086.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda różnic skończonych
płyta pochylona
tarcie
chemically reactive species
Nusselt number
skin friction
finite-difference methods
inclined plate
Opis:
A numerical solution of a transient natural convection flow past a semi-infinite inclined plate under the combined buoyancy effects of heat and mass transfer along with chemical reaction is presented herewith. The governing boundary layer equations for the above flow problem for a first order homogeneous chemical reaction are set up and non-dimensionalised. An implicit finite difference method is employed to solve the unsteady, nonlinear, integro and coupled partial differential equation. Numerical results are presented for various parameters occurring in the problem. The unsteady velocity, temperature and concentration profiles, local and average skin friction, Nusselt number and Sherwood number are studied for both a generative and destructive reaction.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 905-922
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MHD natural convection flow with radiative heat transfer past an impulsively moving vertical plate with ramped temperature in the presence of hall current and thermal diffusion
Autorzy:
Seth, G. S.
Mahato, G. K.
Sarkar, S.
Powiązania:
https://bibliotekanauki.pl/articles/955266.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja naturalna
dyfuzja termiczna
promieniowanie cieplne
MHD natural convection
Hall current
ramped temperature
thermal diffusion
thermal radiation
Opis:
An investigation on an unsteady MHD natural convection flow with radiative heat transfer of a viscous, incompressible, electrically conducting and optically thick fluid past an impulsively moving vertical plate with ramped temperature in a porous medium in the presence of a Hall current and thermal diffusion is carried out. An exact solution of momentum and energy equations, under Boussinesq and Rosseland approximations, is obtained in a closed form by the Laplace transform technique for both ramped temperature and isothermal plates. Expressions for the skin friction and Nusselt number for both ramped temperature and isothermal plates are also derived. The numerical values of fluid velocity and fluid temperature are displayed graphically versus the boundary layer coordinate y for various values of pertinent flow parameters for both ramped temperature and isothermal plates. The numerical values of the skin friction due to primary and secondary flows are presented in tabular form for various values of pertinent flow parameters.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 4; 1201-1220
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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