Abstract We investigate the effect of relativistic ponderomotive force on the propagation of shock waves in relativistic degenerate plasma, which is relevant to high-intensity laser-plasma experiments aimed at replicating extreme conditions on white dwarfs. We derive the KdV-Burger’s equation by incorporating the density modification induced by the ponderomotive force and hence demonstrate that this equation is a suitable model for shock waves affected by ponderomotive force. Unlike previous studies that use ponderomotive force as a source of nonlinearity to derive the nonlinear Schrödinger equation for envelope solitons, our study focuses on the effect of ponderomotive force on shocks produced by the intense laser. We show that the ponderomotive force can significantly modify the strength and shape of shock waves, providing insight into the underlying physics of shock waves in relativistic degenerate plasmas which may help to better understand experimental observations in this regime.
{"title":"Effect of relativistic ponderomotive force on shock waves in a relativistic degenerate plasma","authors":"Hamza Abrar, S. Noureen, F. Aziz","doi":"10.1515/zna-2023-0064","DOIUrl":"https://doi.org/10.1515/zna-2023-0064","url":null,"abstract":"Abstract We investigate the effect of relativistic ponderomotive force on the propagation of shock waves in relativistic degenerate plasma, which is relevant to high-intensity laser-plasma experiments aimed at replicating extreme conditions on white dwarfs. We derive the KdV-Burger’s equation by incorporating the density modification induced by the ponderomotive force and hence demonstrate that this equation is a suitable model for shock waves affected by ponderomotive force. Unlike previous studies that use ponderomotive force as a source of nonlinearity to derive the nonlinear Schrödinger equation for envelope solitons, our study focuses on the effect of ponderomotive force on shocks produced by the intense laser. We show that the ponderomotive force can significantly modify the strength and shape of shock waves, providing insight into the underlying physics of shock waves in relativistic degenerate plasmas which may help to better understand experimental observations in this regime.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"87 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78960430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Farag, K. Abd-Allah, G. Turky, M. El-Okr, W. Abu-raia, A. Saeed
Abstract A blue emitter of Er3+ ions doped a host glass of a chemical composition 30B2O3–30Bi2O3–20Li2O–10BaO–10PbO was fabricated to be used in optoelectronics devices. Four proposed concentrations of Er2O3, which are 0.5, 1, 2, and 4 mol%, were suggested to study the impact of Er3+ ions on the structural, thermal, and photoluminescence properties of the considered host glass, respectively. The phase checking of the produced glasses using X-ray diffraction patterns showed the amorphicity phase formation. Impact of Er3+ ions on the structural properties of the considered host glass network was extensively studied through the occurred variations in XRD patterns, density and density-based parameters, and FTIR spectra. Thermally, the considered glasses have high thermal stability and high glass formability. Optically, the optical band gap, which ranged between 2.18 and 2.56 eV, signifies that the considered glasses have a semiconducting nature. Under 540 nm excitation wavelength, three bands were emitted in the blue region at 450, 462, and 486 nm and two in the violet region at 412 and 427 nm. Chromaticity analysis through CIE 1931 chromaticity diagram showed a strong blue light emission from the produced glasses. The blue light color purity of the considered glasses ranged between 90.887 and 92.324 %. Hence, the considered glasses have suitable characteristics that make them a good choice as blue light-emitting diodes in the optoelectronics devices.
{"title":"Blue light-emitting diode of Er3+-doped borate glass for optoelectronics devices","authors":"M. Farag, K. Abd-Allah, G. Turky, M. El-Okr, W. Abu-raia, A. Saeed","doi":"10.1515/zna-2023-0075","DOIUrl":"https://doi.org/10.1515/zna-2023-0075","url":null,"abstract":"Abstract A blue emitter of Er3+ ions doped a host glass of a chemical composition 30B2O3–30Bi2O3–20Li2O–10BaO–10PbO was fabricated to be used in optoelectronics devices. Four proposed concentrations of Er2O3, which are 0.5, 1, 2, and 4 mol%, were suggested to study the impact of Er3+ ions on the structural, thermal, and photoluminescence properties of the considered host glass, respectively. The phase checking of the produced glasses using X-ray diffraction patterns showed the amorphicity phase formation. Impact of Er3+ ions on the structural properties of the considered host glass network was extensively studied through the occurred variations in XRD patterns, density and density-based parameters, and FTIR spectra. Thermally, the considered glasses have high thermal stability and high glass formability. Optically, the optical band gap, which ranged between 2.18 and 2.56 eV, signifies that the considered glasses have a semiconducting nature. Under 540 nm excitation wavelength, three bands were emitted in the blue region at 450, 462, and 486 nm and two in the violet region at 412 and 427 nm. Chromaticity analysis through CIE 1931 chromaticity diagram showed a strong blue light emission from the produced glasses. The blue light color purity of the considered glasses ranged between 90.887 and 92.324 %. Hence, the considered glasses have suitable characteristics that make them a good choice as blue light-emitting diodes in the optoelectronics devices.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79486531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This article discusses a mathematical model for the electrokinetic and Darcy’s resistance of Williamson fluid in an electroosmotic pumping environment. The zeta potential at walls aids in peristaltic movement, and porous dissipation is incorporated into this modulation by the Williamson fluid’s material parameters. Through the use of Debye-Huckel approximations, long wavelengths, and low Reynolds numbers, the model equations are simplified. Mathematica software is used to produce analytical and numerical results, and plots and analyses are done using the included parameters on physical quantities of interest. This study has various practical applications, such as modifying belt resistance in laboratory drainage testing and improving pipeline design. It could also potentially aid in the development of blood filtration and purification techniques and optimize drug delivery systems that utilize fluids. It is observed that the modified Darcy’s law is more accurate for porosity effects in electroosmotic peristaltic channels and results in higher shear stress at the channel wall compared to Darcy’s law.
{"title":"Analysis of Williamson fluid flow incorporating Darcy’s resistance and electro kinetics: analytical and numerical results","authors":"S. Noreen, Ali J. Chamkha, Aqsa Jahan","doi":"10.1515/zna-2023-0052","DOIUrl":"https://doi.org/10.1515/zna-2023-0052","url":null,"abstract":"Abstract This article discusses a mathematical model for the electrokinetic and Darcy’s resistance of Williamson fluid in an electroosmotic pumping environment. The zeta potential at walls aids in peristaltic movement, and porous dissipation is incorporated into this modulation by the Williamson fluid’s material parameters. Through the use of Debye-Huckel approximations, long wavelengths, and low Reynolds numbers, the model equations are simplified. Mathematica software is used to produce analytical and numerical results, and plots and analyses are done using the included parameters on physical quantities of interest. This study has various practical applications, such as modifying belt resistance in laboratory drainage testing and improving pipeline design. It could also potentially aid in the development of blood filtration and purification techniques and optimize drug delivery systems that utilize fluids. It is observed that the modified Darcy’s law is more accurate for porosity effects in electroosmotic peristaltic channels and results in higher shear stress at the channel wall compared to Darcy’s law.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"01 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86257917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The Heisenberg supermagnet model is a significant supersymmetric integrable model which is the superextension of the Heisenberg ferromagnet model. This paper is concerned with the construction of the multi-component (1+1) and (2+1)-dimensional Heisenberg supermagnet models with two distinct quadratic constraints of the superspin variables. In terms of the multi-component gauge transformation, we construct their multi-component gauge equivalent counterparts, i.e., the multi-component (1+1) and (2+1)-dimensional super nonlinear Schrödinger equations and fermionic nonlinear Schrödinger equations, respectively.
{"title":"On the multi-component Heisenberg supermagnet models in (1+1) and (2+1)-dimensions","authors":"Mengyang Gao, Zhaowen Yan","doi":"10.1515/zna-2023-0078","DOIUrl":"https://doi.org/10.1515/zna-2023-0078","url":null,"abstract":"Abstract The Heisenberg supermagnet model is a significant supersymmetric integrable model which is the superextension of the Heisenberg ferromagnet model. This paper is concerned with the construction of the multi-component (1+1) and (2+1)-dimensional Heisenberg supermagnet models with two distinct quadratic constraints of the superspin variables. In terms of the multi-component gauge transformation, we construct their multi-component gauge equivalent counterparts, i.e., the multi-component (1+1) and (2+1)-dimensional super nonlinear Schrödinger equations and fermionic nonlinear Schrödinger equations, respectively.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"13 1","pages":"597 - 604"},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82762115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Due to nonlocal and strain gradient effects with rigid and deformable boundary conditions, the thermal vibration behavior of perforated nanobeams resting on a Winkler elastic foundation (WEF) is examined in this paper. The Stokes transformation and Fourier series have been used to achieve this goal and to determine the thermal vibration behavior under various boundary conditions, including deformable and non-deformable ones. The perforated nanobeams’ boundary conditions are considered deformable, and the nonlocal strain gradient theory accounts for the size dependency. The problem is modeled as an eigenvalue problem. The effect of parameters such as the number of holes, elastic foundation, nonlocal and strain gradient, deformable boundaries and size on the solution is considered. The effects of various parameters, such as the length of the perforated beam, number of holes, filling ratio, thermal effect parameter, small-scale parameters and foundation parameter, on the thermal vibration behavior of the perforated nanobeam, are then illustrated using a set of numerical examples. As a result of the analysis, it was determined that the vibration frequency of the nanobeam was most affected by the changes in the dimensionless WEF parameter in the first mode and the changes in the internal length parameter when all modes were considered.
{"title":"Thermal vibration of perforated nanobeams with deformable boundary conditions via nonlocal strain gradient theory","authors":"Uğur Kafkas, B. Uzun, M. Yaylı, Gökhan Güçlü","doi":"10.1515/zna-2023-0088","DOIUrl":"https://doi.org/10.1515/zna-2023-0088","url":null,"abstract":"Abstract Due to nonlocal and strain gradient effects with rigid and deformable boundary conditions, the thermal vibration behavior of perforated nanobeams resting on a Winkler elastic foundation (WEF) is examined in this paper. The Stokes transformation and Fourier series have been used to achieve this goal and to determine the thermal vibration behavior under various boundary conditions, including deformable and non-deformable ones. The perforated nanobeams’ boundary conditions are considered deformable, and the nonlocal strain gradient theory accounts for the size dependency. The problem is modeled as an eigenvalue problem. The effect of parameters such as the number of holes, elastic foundation, nonlocal and strain gradient, deformable boundaries and size on the solution is considered. The effects of various parameters, such as the length of the perforated beam, number of holes, filling ratio, thermal effect parameter, small-scale parameters and foundation parameter, on the thermal vibration behavior of the perforated nanobeam, are then illustrated using a set of numerical examples. As a result of the analysis, it was determined that the vibration frequency of the nanobeam was most affected by the changes in the dimensionless WEF parameter in the first mode and the changes in the internal length parameter when all modes were considered.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87413933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this paper, the perturbed Gerdjikov–Ivanov equation with spatio-temporal dispersion is investigated. The trial equation method, the complex envelope travelling wave transformation, and the complete discriminant system for polynomial method, respectively, are all utilized. As a consequence, twenty-eight exact chirped solutions are obtained, and some representative two-dimensional patterns under concrete parameters are presented. The results acquired are conducive to studying the dynamic behavior of solitons.
{"title":"Exact chirped solutions of the perturbed Gerdjikov–Ivanov equation with spatio-temporal dispersion","authors":"Ming Tang","doi":"10.1515/zna-2023-0093","DOIUrl":"https://doi.org/10.1515/zna-2023-0093","url":null,"abstract":"Abstract In this paper, the perturbed Gerdjikov–Ivanov equation with spatio-temporal dispersion is investigated. The trial equation method, the complex envelope travelling wave transformation, and the complete discriminant system for polynomial method, respectively, are all utilized. As a consequence, twenty-eight exact chirped solutions are obtained, and some representative two-dimensional patterns under concrete parameters are presented. The results acquired are conducive to studying the dynamic behavior of solitons.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81743703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aleeza Jamshaid, M. Rani, A. Shah, R. Siddiqui, R. Neffati, A. Chandio, A. Mahmood
Abstract The article presents research on the synthesis and characterization of a nanocomposite material consisting of graphene oxide (GO) decorated with calcium oxide (CaO), for the use in energy storage. The co-precipitation method was used to prepare the nanocomposite. The presence of CaO and GO in the sample was confirmed by X-ray diffraction (XRD), which revealed a crystallite size of 18 nm for CaO and 9 nm of CaO/GO. The scanning electron microscopy (SEM) images showed a well-dispersed nanocomposite structure, and energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of Ca, C, and O elements in the sample. Fourier-transform infrared (FTIR) spectroscopy was used to analyze the chemical composition and structural properties of the nanocomposite. UV-visible spectroscopy revealed a direct band gap of 3.78 eV for the nanocomposite, indicating its potential application for use in electrochemical energy storage and photoconductive devices. Zeta potential measurement indicated good physical stability of the nanocomposite. These results suggest that the CaO/GO nanocomposite has promising properties for various technological applications, particularly in the field of thermal energy storage.
{"title":"Calcium oxide decorated graphene oxide nanocomposite as energy storage medium: synthesis and characterization","authors":"Aleeza Jamshaid, M. Rani, A. Shah, R. Siddiqui, R. Neffati, A. Chandio, A. Mahmood","doi":"10.1515/zna-2023-0053","DOIUrl":"https://doi.org/10.1515/zna-2023-0053","url":null,"abstract":"Abstract The article presents research on the synthesis and characterization of a nanocomposite material consisting of graphene oxide (GO) decorated with calcium oxide (CaO), for the use in energy storage. The co-precipitation method was used to prepare the nanocomposite. The presence of CaO and GO in the sample was confirmed by X-ray diffraction (XRD), which revealed a crystallite size of 18 nm for CaO and 9 nm of CaO/GO. The scanning electron microscopy (SEM) images showed a well-dispersed nanocomposite structure, and energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of Ca, C, and O elements in the sample. Fourier-transform infrared (FTIR) spectroscopy was used to analyze the chemical composition and structural properties of the nanocomposite. UV-visible spectroscopy revealed a direct band gap of 3.78 eV for the nanocomposite, indicating its potential application for use in electrochemical energy storage and photoconductive devices. Zeta potential measurement indicated good physical stability of the nanocomposite. These results suggest that the CaO/GO nanocomposite has promising properties for various technological applications, particularly in the field of thermal energy storage.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"284 1","pages":"659 - 668"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74368400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The structural parameters and performance evaluation metrics of 242 promising all-silica zeolites to rank and screen out the top candidates for CO2/N2 separation are obtained by using molecular simulations combined with high-throughput calculations. By setting the pore size range of the material, three top zeolites with the highest adsorption selectivity for CO2 molecules are screened to further investigate the adsorption and separation for CO2 and N2 molecules. The GCMC method was used to calculate the adsorption isotherm, heat of adsorption, adsorption selectivity and centroid distribution density under different feed ratios of CO2/N2 mixed components. The zeolite exhibits a high CO2 adsorption capacity with the maximum pore size of 4–8 Å, the surface area of 1400 m2/g and the pore volume of 0.2–0.4 cm3/g, and best adsorption selectivity for CO2 at the pore size of 4 Å and pore volume of 0.2 cm3/g in the CO2/N2 mixed systems. Zeolite has higher adsorption selectivity for CO2 with low amount of CO2, which is favorable for the removal of a small amount of CO2 molecules. The geometrical structure of the material plays an important role for the adsorption capacity and spatial distribution of the adsorbate molecules in all-silicon zeolites.
{"title":"Revealing the structure–property relationship of all-silica zeolites for the carbon dioxide capture: a high throughput screening study","authors":"Liu Xiuying, Hao Chen, Junpeng Yuan, Jilong Huang, Xiaodong Li, Jing-Zhi Yu","doi":"10.1515/zna-2023-0065","DOIUrl":"https://doi.org/10.1515/zna-2023-0065","url":null,"abstract":"Abstract The structural parameters and performance evaluation metrics of 242 promising all-silica zeolites to rank and screen out the top candidates for CO2/N2 separation are obtained by using molecular simulations combined with high-throughput calculations. By setting the pore size range of the material, three top zeolites with the highest adsorption selectivity for CO2 molecules are screened to further investigate the adsorption and separation for CO2 and N2 molecules. The GCMC method was used to calculate the adsorption isotherm, heat of adsorption, adsorption selectivity and centroid distribution density under different feed ratios of CO2/N2 mixed components. The zeolite exhibits a high CO2 adsorption capacity with the maximum pore size of 4–8 Å, the surface area of 1400 m2/g and the pore volume of 0.2–0.4 cm3/g, and best adsorption selectivity for CO2 at the pore size of 4 Å and pore volume of 0.2 cm3/g in the CO2/N2 mixed systems. Zeolite has higher adsorption selectivity for CO2 with low amount of CO2, which is favorable for the removal of a small amount of CO2 molecules. The geometrical structure of the material plays an important role for the adsorption capacity and spatial distribution of the adsorbate molecules in all-silicon zeolites.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"120 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76917308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fuli He, A. Amiri Delouei, R. Ellahi, S. Alamri, A. Emamian, Saeed Ghorbani
Abstract A novel model on 2D unsteady conductive heat transfer in an infinite hollow cylinder is proposed. The cylinder is made of functionally graded material (FGM) that has variable properties both in radial and angular directions. Volumetric heat capacity and thermal conductivity coefficient are changed according to the power function of the radius. In the presence of variable coefficients, the governing equations of unsteady heat transfer in FGMs have caused the complexity. The Laplace transform method is used to transfer the energy equation from time to frequency domain whereas the meromorphic function is used for the inverse Laplace transform to obtain the desired solutions. The closed form solutions have been well validated and the results have been presented for different values of functionally graded indices for thermal conductivity coefficients and volumetric heat capacity. Two different FGM cases with different complicated thermal boundary conditions have been investigated. The first case has a constant temperature in the inner radius and a variable heat flux along with the convection condition in the outer radius. In the second case, the inner radius has a specific harmonic temperature and the outer radius is exposed to the convective conditions. It was observed that in both cases, the temperature value in the cylinder decreases with the increase of the FG index for the conductivity coefficient. The presented analytical solution provides a good tool for validating unsteady numerical solutions presented in the field of heat transfer in FGMs.
{"title":"Unsteady temperature distribution in a cylinder made of functionally graded materials under circumferentially-varying convective heat transfer boundary conditions","authors":"Fuli He, A. Amiri Delouei, R. Ellahi, S. Alamri, A. Emamian, Saeed Ghorbani","doi":"10.1515/zna-2023-0039","DOIUrl":"https://doi.org/10.1515/zna-2023-0039","url":null,"abstract":"Abstract A novel model on 2D unsteady conductive heat transfer in an infinite hollow cylinder is proposed. The cylinder is made of functionally graded material (FGM) that has variable properties both in radial and angular directions. Volumetric heat capacity and thermal conductivity coefficient are changed according to the power function of the radius. In the presence of variable coefficients, the governing equations of unsteady heat transfer in FGMs have caused the complexity. The Laplace transform method is used to transfer the energy equation from time to frequency domain whereas the meromorphic function is used for the inverse Laplace transform to obtain the desired solutions. The closed form solutions have been well validated and the results have been presented for different values of functionally graded indices for thermal conductivity coefficients and volumetric heat capacity. Two different FGM cases with different complicated thermal boundary conditions have been investigated. The first case has a constant temperature in the inner radius and a variable heat flux along with the convection condition in the outer radius. In the second case, the inner radius has a specific harmonic temperature and the outer radius is exposed to the convective conditions. It was observed that in both cases, the temperature value in the cylinder decreases with the increase of the FG index for the conductivity coefficient. The presented analytical solution provides a good tool for validating unsteady numerical solutions presented in the field of heat transfer in FGMs.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85869383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Plaque reduces the conductivity of the blood vessel and its shape is more important than its quantity. We show that, for given quantity, the conductivity is maximal if the plaque forms a uniform layer next to the vessel wall and leaves a circular hole in the middle. On the other hand, for any quantity of the plaque a shape can be found such that the conductivity of the vessel is arbitrary close to zero.
{"title":"Effects of plaque shape on arterial blood flow","authors":"Karla Marušić, E. Marušić‐Paloka, M. Vrdoljak","doi":"10.1515/zna-2023-0059","DOIUrl":"https://doi.org/10.1515/zna-2023-0059","url":null,"abstract":"Abstract Plaque reduces the conductivity of the blood vessel and its shape is more important than its quantity. We show that, for given quantity, the conductivity is maximal if the plaque forms a uniform layer next to the vessel wall and leaves a circular hole in the middle. On the other hand, for any quantity of the plaque a shape can be found such that the conductivity of the vessel is arbitrary close to zero.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"100 1 1","pages":"643 - 649"},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83858491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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