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Wyszukujesz frazę "Diffusion" wg kryterium: Wszystkie pola


Tytuł:
Economic and institutional determinants of environmental health and sustainability: Spatial and nonlinear effects for a panel of worldwide countries
Autorzy:
Dinu, Vasile
Dragoş, Cristian Mihai
Mare, Codruţa
Dragoş, Simona Laura
Mare, Roxana
Powiązania:
https://bibliotekanauki.pl/articles/39833161.pdf
Data publikacji:
2024
Wydawca:
Instytut Badań Gospodarczych
Tematy:
contagion and diffusion
spatial panel
threshold panel
environmental health
environmental performance
environmental sustainability
Opis:
Research background: This study identifies the key factors influencing environmental health across a global panel of countries, focusing on protection from environmental hazards, as informed by the existing literature, while also shedding light on novel aspects of these causal relationships. Purpose of the article: This study aims to reveal, through a comprehensive review of the relevant literature, the underexplored phenomena of spatial diffusion and contagion of national environmental behaviors and the nonlinear dynamics between environmental performance and its determinants, acknowledging the significant diversity in the characteristics and behaviors of the countries studied. Methods: Spatial analysis and econometric methods, including spatial panel regression alongside dynamic panel models using threshold techniques, were employed to meet the study’s objectives. Findings & value added: This study’s major finding is that environmental performance across nations shows significant clustering influenced by economic and institutional factors. This clustering effect arises from spatial contagion and diffusion processes, as evidenced by spatial panel regression analysis. Furthermore, this study demonstrates that variations in environmental behavior can be attributed to differing levels of development and specific internal conditions within countries. Notably, a country’s gross domestic product and the proportion of industries in its economy have a substantial effect on its environmental health practices, establishing distinct impact thresholds. This research enriches academic dialogue by illustrating, through these thresholds, that in less developed countries, an increased industrial share leads to environmental degradation. Moreover, the influence of the other examined factors varied depending on the category of the country under review, highlighting the nuanced effects of economic and institutional variables on environmental outcomes.
Źródło:
Oeconomia Copernicana; 2024, 15, 1; 195-227
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Encapsulation of genistein in glycidylated G3 polyamidoamine dendrimers enables diffusion of genistein through biological membranes and anti-nematode activity of the encapsulate
Autorzy:
Filipowicz-Rachwał, Aleksandra
Drozdowska, Joanna
Zagórska-Dziok, Martyna
Uram, Łukasz
Wołowiec, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/40556674.pdf
Data publikacji:
2024-06-30
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
C. elegans
fibroblast BJ toxicity
genistein
keratinocyte HaCaT toxicity
PAMAM dendrimer
Opis:
Introduction and aim. Poorly soluble isoflavonoid genistein is known as an anti-nematode agent and also it decreases the risk of certain types of cancer. The biological activity of genistein is limited mostly by its low solubility. Therefore many attempts to increase genistein solubility in water were reported. We applied a polyamidoamine dendrimer, modified its surface by glycidylation, and used this macromolecule as a guest for genistein. Material and methods. Polyamidoamine dendrimer 3rd generation was substituted with 64 glycidol residues to obtain a macromolecule host for genistein. The stoichiometry of this host-guest complex was determined. The complex was tested for skin model permeability, toxicity on fibroblast (BJ) and keratinocyte (HaCaT) cell lines in vitro and anthelmintic activity on the Caenorhabditis elegans nematode. Results. The partition coefficient of genistein between octanol and water was determined (KO/W). The 1:1 host-guest complex was isolated and used as drug delivery system for genistein delivery. PAMAM G3 glycidyled dendrimer containing genistein indicated an anthelmintic activity at 50 μM concentration. Conclusion. The solubility of genistein in water increases 640 times in presence of an equimolar concentration of the dendrimer. One molecule of host dendrimer encapsulates 3 molecules of genistein. The encapsulate is an efficient anti-nematode formulation.
Źródło:
European Journal of Clinical and Experimental Medicine; 2024, 22, 2; 292-299
2544-2406
2544-1361
Pojawia się w:
European Journal of Clinical and Experimental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of photochemical and photothermal effects in soft tissue subjected to laser irradiation
Autorzy:
Jasiński, Marek
Zadoń, Maria
Powiązania:
https://bibliotekanauki.pl/articles/38706609.pdf
Data publikacji:
2024
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
bioheat transfer
optical diffusion equation
photodynamic therapy
boundary element method
finite difference method
transfer biociepła
równanie dyfuzji optycznej
terapia fotodynamiczna
metoda elementów brzegowych
metoda różnic skończonych
Opis:
The purpose of this study is to analyze the phenomena that occur in biological tissueduring photodynamic therapy (PDT). Under the influence of the laser, triplet oxygen istransformed into singlet oxygen, which is cytotoxic to cancer tissue. The impact of thelaser on the tissue may also be accompanied by changes in the thermophysical parameters,e.g., perfusion, which can affect the supply of oxygen to the tissue and, consequently,the outcome of the therapy. The proposed model uses the optical diffusion equation,the Pennes bioheat transfer equation, and reactions equations for PDT. The connectionbetween bioheat transfer and PDT models is taken into account through the respectiverelationships between perfusion rate, capillary blood velocity, and the maximum oxygensupply rate. Furthermore, a method is proposed to model abnormal vascular patterns inthe tumor subdomain. The boundary element method and the finite difference methodwere used in the numerical implementation stage.
Źródło:
Computer Assisted Methods in Engineering and Science; 2024, 31, 1; 29-50
2299-3649
Pojawia się w:
Computer Assisted Methods in Engineering and Science
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
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
Artykuł
Tytuł:
ADDP : Anomaly Detection Based on Denoising Pretraining
Autorzy:
Ge, Xianlei
Li, Xiaoyan
Zhang, Zhipeng
Powiązania:
https://bibliotekanauki.pl/articles/27311945.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Anomaly Detection
Diffusion Models
image denoising
Pretraining
transfer learning
Opis:
Acquiring labels in anomaly detection tasks is expensive and challenging. Therefore, as an effective way to improve efficiency, pretraining is widely used in anomaly detection models, which enriches the model's representation capabilities, thereby enhancing both performance and efficiency in anomaly detection. In most pretraining methods, the decoder is typically randomly initialized. Drawing inspiration from the diffusion model, this paper proposed to use denoising as a task to pretrain the decoder in anomaly detection, which is trained to reconstruct the original noise-free input. Denoising requires the model to learn the structure, patterns, and related features of the data, particularly when training samples are limited. This paper explored two approaches on anomaly detection: simultaneous denoising pretraining for encoder and decoder, denoising pretraining for only decoder. Experimental results demonstrate the effectiveness of this method on improving model’s performance. Particularly, when the number of samples is limited, the improvement is more pronounced.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 4; 719--726
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
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:
Asymptotic analysis of the steady advection-diffusion problem in axial domains
Autorzy:
Morales, Fernando A.
Powiązania:
https://bibliotekanauki.pl/articles/29519253.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
asymptotic analysis
mixed-type variational formulations
advection-diffusion
Opis:
We present the asymptotic analysis of the steady advection-diffusion equation in a thin tube. The problem is modeled in a mixed-type variational formulation, in order to separate the phenomenon in the axial direction and a transverse one. Such formulation makes visible the natural separation of scales within the problem and permits a successful asymptotic analysis, delivering a limiting form, free from the initial geometric singularity and suitable for approximating the original one. Furthermore, it is shown that the limiting problem can be simplified to a significantly simpler structure.
Źródło:
Opuscula Mathematica; 2023, 43, 2; 199-220
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamical properties of a modified chaotic Colpitts oscillator with triangular wave non-linearity
Autorzy:
Suresh, Rasappan
Sathish Kumar, Kumaravel
Regan, Murugesan
Niranjan Kumar, K. A.
Narmada Devi, R.
Obaid, Ahmed J.
Powiązania:
https://bibliotekanauki.pl/articles/27312004.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
chaos
Colpitts oscillator
Lyapunov exponent
diffusion
stability
synchronization
triangular wave non-linearity
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 for triangular wave non-linearity. 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; 2023, 33, 1; 25--53
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fundamental solutions in the generalized theory of thermoelastic diffusion with triple porosity
Autorzy:
Kansal, Tarun
Powiązania:
https://bibliotekanauki.pl/articles/38912689.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
thermoelastic diffusion
triple porosity
pores
steady oscillations
Opis:
The main aim of this paper is to derive the basic governing equations for an anisotropic thermoelastic medium with mass diffusion and triple porosity. Additionally, the fundamental solutions of a system of equations for steady, pseudo-, quasi-static oscillations and equilibrium are constructed.
Źródło:
Engineering Transactions; 2023, 71, 4; 473-505
0867-888X
Pojawia się w:
Engineering Transactions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gas Nitriding of the Near-Beta-Titanium Alloy
Autorzy:
Luk’yanenko, Alexander G.
Pohrelyuk, Iryna M.
Fedirko, Viktor M.
Molyar, A. G.
Trush, Vasyl
Kravchyshyn, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/27313871.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
near-beta-titanium alloy
nitriding
kinetics
diffusion
microhardness
Opis:
The present research investigates the nitriding kinetics of the near-beta-titanium alloy of Ti-Al-Nb-Fe-Zr-Mo-V system at 750, 800, and 850°C in gaseous nitrogen at 105 Pa for 2, 4, and 8 h. The parabolic coefficient kp of the layer’s growth rate and the nitriding activation energy E are set as the kinetic parameters of the nitrided layer’s growth. The activation energy for the formation of a nitride layer is ~108 kJ/mol. The authors discuss the morphology of the nitride layers as well as their roughness and surface hardness. The study determines the effective diffusion coefficient for the growth of diffusion layers in the temperature range of 750...850°C: Def = D0× exp (-E/RT), where D0 = 0.0177 m2 /s; E = 215.7 kJ/mol. The friction coefficient of the disk from nearbeta-titanium alloy with a bronze block is lowered by significantly more than 10 times after gas nitriding, and the temperature in the friction zone is reduced by 2.5 times.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 431--438
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
Tytuł:
Modeling of cracking of the concrete cover taking into account the coupled diffusion/mechanical process
Autorzy:
Yurkova, Kseniya
Krykowski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/38703557.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
corrosion
FEM
elastic-plastic
cover cracking
korozja
MES
sprężysto-plastikowy
pękanie pokrywy
Opis:
This paper presents a mechanical-diffusion one-way coupled corrosion model that allows the analysis of both accelerated and natural reinforcement corrosion. The impact of corrosion products on the concrete cover is exerted using the tensor of the volumetric strain rate dependent on the rate of concentration change of corrosion products or the rate of concentration change of ferrous ions. The approach proposed in the paper enables the analysis of the impact of corrosion products with a complex composition that depends on the intensity and density of the electric current. The model also enables the analysis of cases where the distribution of corrosion products is inhomogeneous around the circumference of the rebar.
Źródło:
Computer Assisted Methods in Engineering and Science; 2023, 30, 4; 481-503
2299-3649
Pojawia się w:
Computer Assisted Methods in Engineering and Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation Process of Coating Interlayer and the Performance of EH40/2205-Clad Plate with Interlayer
Autorzy:
Feng, K.K.
Yi, Yali
Qin, Y.
Jin, Herong R.
Powiązania:
https://bibliotekanauki.pl/articles/27765059.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
element diffusion
interlayer coating
mechanical properties
numerical simulation
stainless steel-clad plate
Opis:
This study aimed to investigate the effect of different coating processes on interlayer coating using ProCAST software and identify the preferred coating process so as to prepare an EH40/2205 composite plate with a coating interlayer of Ni-5 Fe-15 Co (wt.%) displaying good performance. The preparation and characterization tests were conducted to analyze the interlayer coating, the diffusion of elements at the bonding interface and the mechanical properties of the hot-rolled composite plate. The results showed that the coating rate increased linearly with an increase in the initial coating temperature, pressure difference and the width ratio of the suction layer. The interlayer coating was complete under the guidance of optimized process parameters, and the test results and simulations confirmed each other. The coated interlayer successfully blocked the diffusion of elements between the bonding surfaces. The tensile strength of the rolled composite plate was 580 MPa, which met the needs of the project. The tensile shear fracture occurred at EH40, which proved that the plate was well bonded.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 591--598
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on optimum design method of cushion thickness in composite foundation under rigid base
Autorzy:
Xiao, Yaoting
Wang, Jing
Powiązania:
https://bibliotekanauki.pl/articles/27312123.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
fundament kompozytowy
grubość
konstrukcja optymalna
rozkład naprężeń
composite foundation
cushion thickness
optimum design
stress diffusion
Opis:
At present, the cushion thickness of composite foundation under rigid base is mostly selected by the experience of the engineer, which is of great arbitrariness. In order to improve this problem, the optimum design method of cushion thickness is proposed by theoretical research. First, the stress diffusion line in the cushion is assumed to be a quadratic curve, and the critical diffusion thickness of the pile top stress is obtained. Then, by analyzing the relative deformation between soil and pile, pile top penetration into the critical cushion thickness is proposed. Finally, based on the relationship between stress ratio of pile to soil and cushion thickness, the calculation method of optimum cushion thickness is put forward. The application of engineering cases shows that the proposed method has better calculation results, which attests to the correctness of the method. The method can be used for the optimal design of cushion thickness of single-type-pile or multi-type-pile composite foundation.
Źródło:
Archives of Civil Engineering; 2023, 69, 2; 471--482
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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