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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
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:
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
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:
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
Artykuł
Tytuł:
FORMULATION AND EVALUATION OF INDOMETHACIN LOADED NANOSPONGES FOR ORAL DELIVERY
Autorzy:
Abbas, Nasir
Sarwar, Komal
Irfan, Muhammad
Hussain, Amjad
Mehmood, Rabia
Arshad, Muhammad S.
Shah, Pervaiz A.
Powiązania:
https://bibliotekanauki.pl/articles/895238.pdf
Data publikacji:
2018-10-31
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
sustained release
indomethacin
Nanosponges
Emulsion solvent diffusion method
Franz diffusion cell
Opis:
Nanosponges (NS) loaded sustained release tablet formulations of a non-steroidal anti-inflammatory drug; Indomethacin were successfully developed and evaluated for their pharmaceutical properties. Twelve nanosponge formulations were fabricated by solvent diffusion method by using different ratios of drug and polymers (ethyl cellulose and polyvinyl alcohol). Particle size of all the formulations was in the nano range of 221 to 625 nm and it was found dependent on the polymer concentration. Drug loading and entrapment efficiency was ranged in 32.2 to 59.4 % and 30.1 to 64.8 %, respectively. Formulations with equal proportion of drug and polymer resulted in higher values of drug loading and entrapment efficiency. Percent yield was also found dependent on the relative drug polymer ratio with highest value of 51 % was achieved for the formulation having same drug to polymer ratio. SEM results confirmed the formation of spherical and porous structures. Structural analysis by Fourier transform infrared spectroscopy (FTIR), powder x-ray diffraction (PXRD) showed the absence of any interaction between drug and polymer. In comparison to pure drug, NS formulations showed a linear intrinsic dissolution rate (IDR) profile depicting a controlled release profile. Diffusion studies of NS formulations performed by Franz diffusion cell and dialysis bag methods showed comparable results in terms of precision and linearity of diffusion profile. Tablets prepared from the drug loaded NS showed acceptable values for hardness, friability and drug content. Release of drug from NS tablets was confirmed as sustained release behaviour.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2018, 75, 5; 1201-1213
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
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
Artykuł
Tytuł:
A laboratory facility (RTD) to study radon transport through modeled soil bed: results of preliminary measurements
Autorzy:
Kozak, K.
Mazur, J.
Hovhannisyan, H.
Powiązania:
https://bibliotekanauki.pl/articles/148126.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radon
transport
facility
diffusion
Opis:
The paper describes a laboratory facility (radon transport device – RTD) which makes it possible to study radon transport. The measuring position is a vertical cylindrical vessel with a height of 202 cm and a diameter of 24 cm. It can be filled with sand, gravel or other soil materials to be studied. The facility is providing radon gas from the source to the studied material and making it possible to measure radon concentration at different vertical distances from the source. The parameters of the medium (temperature, humidity) can be measured at the same time. The preliminary measurements using the RTD with sand as medium are presented.
Źródło:
Nukleonika; 2009, 54, 3; 193-198
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
Tytuł:
Depth Analysis of Crystalline Silicon Used for Radiation-Hard Detectors
Autorzy:
Moloi, S.
McPherson, M.
Powiązania:
https://bibliotekanauki.pl/articles/1033420.pdf
Data publikacji:
2017-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
silicon
diffusion
XPS
detectors
Opis:
Depth analysis of metal-doped crystalline silicon by the X-ray photoelectron spectroscopy technique is presented in this work. The results from this technique are used to complement those from previous techniques. The metals diffused into the silicon are gold, platinum, erbium, and niobium. In silicon, these metals induce defects that are responsible for relaxation behaviour of the material. Relaxation material is radiation-hard since the effects of radiation on devices fabricated on the material are suppressed. Considerable amounts of gold, platinum, and niobium are found in the silicon bulk. The results of this work are in good agreement with those reported earlier on the same samples using the Rutherford backscattering technique. The spectra of the natural contaminants, carbon and oxygen, are also analysed in this work.
Źródło:
Acta Physica Polonica A; 2017, 132, 4; 1387-1392
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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
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:
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
Artykuł
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
Artykuł
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
Artykuł
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