Zeitschrift für Naturforschung A最新文献_第10页

Effect of relativistic ponderomotive force on shock waves in a relativistic degenerate plasma 相对论质动势对相对论简并等离子体中激波的影响

Zeitschrift für Naturforschung A Pub Date : 2023-06-19 DOI: 10.1515/zna-2023-0064

Hamza Abrar, S. Noureen, F. Aziz

引用次数: 0

Blue light-emitting diode of Er3+-doped borate glass for optoelectronics devices 光电器件用掺Er3+硼酸盐玻璃蓝色发光二极管

Zeitschrift für Naturforschung A Pub Date : 2023-06-14 DOI: 10.1515/zna-2023-0075

M. Farag, K. Abd-Allah, G. Turky, M. El-Okr, W. Abu-raia, A. Saeed

{"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":null,"pages":null},"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}

引用次数: 1

Analysis of Williamson fluid flow incorporating Darcy’s resistance and electro kinetics: analytical and numerical results 结合达西阻力和电动力学的威廉姆森流体流动分析:分析和数值结果

Zeitschrift für Naturforschung A Pub Date : 2023-06-13 DOI: 10.1515/zna-2023-0052

S. Noreen, Ali J. Chamkha, Aqsa Jahan

{"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":null,"pages":null},"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}

引用次数: 0

On the multi-component Heisenberg supermagnet models in (1+1) and (2+1)-dimensions (1+1)和(2+1)维多分量Heisenberg超磁体模型

Zeitschrift für Naturforschung A Pub Date : 2023-06-12 DOI: 10.1515/zna-2023-0078

Mengyang Gao, Zhaowen Yan

引用次数: 0

Thermal vibration of perforated nanobeams with deformable boundary conditions via nonlocal strain gradient theory 基于非局部应变梯度理论的可变形边界条件下多孔纳米梁的热振动

Zeitschrift für Naturforschung A Pub Date : 2023-06-12 DOI: 10.1515/zna-2023-0088

Uğur Kafkas, B. Uzun, M. Yaylı, Gökhan Güçlü

{"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":null,"pages":null},"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}

引用次数: 1

Exact chirped solutions of the perturbed Gerdjikov–Ivanov equation with spatio-temporal dispersion 具有时空色散的扰动Gerdjikov-Ivanov方程的精确啁啾解

Zeitschrift für Naturforschung A Pub Date : 2023-06-05 DOI: 10.1515/zna-2023-0093

Ming Tang

引用次数: 1

Calcium oxide decorated graphene oxide nanocomposite as energy storage medium: synthesis and characterization 氧化钙修饰氧化石墨烯纳米复合材料储能介质的合成与表征

Zeitschrift für Naturforschung A Pub Date : 2023-05-31 DOI: 10.1515/zna-2023-0053

Aleeza Jamshaid, M. Rani, A. Shah, R. Siddiqui, R. Neffati, A. Chandio, A. Mahmood

{"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":null,"pages":null},"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}

引用次数: 0

Revealing the structure–property relationship of all-silica zeolites for the carbon dioxide capture: a high throughput screening study 揭示用于二氧化碳捕获的全硅沸石的结构-性能关系:高通量筛选研究

Zeitschrift für Naturforschung A Pub Date : 2023-05-31 DOI: 10.1515/zna-2023-0065

Liu Xiuying, Hao Chen, Junpeng Yuan, Jilong Huang, Xiaodong Li, Jing-Zhi Yu

{"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":null,"pages":null},"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}

引用次数: 0

Unsteady temperature distribution in a cylinder made of functionally graded materials under circumferentially-varying convective heat transfer boundary conditions 在周向变对流换热边界条件下，功能梯度材料圆柱体的非定常温度分布

Zeitschrift für Naturforschung A Pub Date : 2023-05-29 DOI: 10.1515/zna-2023-0039

Fuli He, A. Amiri Delouei, R. Ellahi, S. Alamri, A. Emamian, Saeed Ghorbani

{"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":null,"pages":null},"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}

引用次数: 3

Effects of plaque shape on arterial blood flow 斑块形状对动脉血流的影响

Zeitschrift für Naturforschung A Pub Date : 2023-05-25 DOI: 10.1515/zna-2023-0059

Karla Marušić, E. Marušić‐Paloka, M. Vrdoljak

引用次数: 0