Zeitschrift für Naturforschung A最新文献_第3页

Finite-dimensional perturbation of the Dirichlet boundary value problem for the biharmonic equation 双谐方程的迪里夏特边界值问题的有限维扰动

Zeitschrift für Naturforschung A Pub Date : 2024-05-13 DOI: 10.1515/zna-2024-0020

Gulnaz Berikkhanova

{"title":"Finite-dimensional perturbation of the Dirichlet boundary value problem for the biharmonic equation","authors":"Gulnaz Berikkhanova","doi":"10.1515/zna-2024-0020","DOIUrl":"https://doi.org/10.1515/zna-2024-0020","url":null,"abstract":"The biharmonic equation is one of the important equations of mathematical physics, describing the behaviour of harmonic functions in higher-dimensional spaces. The main purpose of this study was to construct a finite-dimensional perturbation for the Dirichlet boundary value problem associated with the biharmonic equation. The methodological basis for this study was an integrated approach that includes mathematical analysis, algebraic methods, operator theory, and the theorem on the existence and uniqueness of a solution for a boundary value. The main tool is a finite-dimensional perturbation, which allows for examining the properties and behaviour of boundary value problems in as much detail as possible. In the study, descriptions of correctly solvable internal boundary value problems for a biharmonic equation in non-simply connected domains were considered in detail. The study is also devoted to the search for solutions and the analytical representation of resolvents of boundary value problems for a biharmonic equation in multi-connected domains. Within the framework of the study, theorems and their consequences were proved, and a finite-dimensional perturbation was constructed for the Dirichlet boundary value problem. Analytical representations of resolvents of boundary value problems for a biharmonic equation in multi-connected domains were also obtained. The examination of a finite-dimensional perturbation of the Dirichlet boundary value problem for a biharmonic equation has expanded the understanding of the properties of this equation in various contexts.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940383","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

Analysis of the flow and thermal-fluid–solid coupling of crude oil in circular pipe caused by variable pressure gradient 变压梯度引起的原油在圆管中的流动和热-流-固耦合分析

Zeitschrift für Naturforschung A Pub Date : 2024-05-09 DOI: 10.1515/zna-2023-0293

Jinxia Jiang, Mengqi Liu, Yan Zhang, Zhen Huang

{"title":"Analysis of the flow and thermal-fluid–solid coupling of crude oil in circular pipe caused by variable pressure gradient","authors":"Jinxia Jiang, Mengqi Liu, Yan Zhang, Zhen Huang","doi":"10.1515/zna-2023-0293","DOIUrl":"https://doi.org/10.1515/zna-2023-0293","url":null,"abstract":"Globally, enhanced oil recovery (EOR) has become a pressing issue as the demand for crude oil continues to increase. This study investigates the flow and thermal-fluid–solid coupling of crude oil in a rod pump during hot water recovery and obtains the maximum recovery of crude oil in a vertical pipeline through numerical analysis. The pressure gradient in the pump barrel was first developed and deduced based on the ideal gas state equation and Bernoulli’s equation. According to the rheological experiment results, it was proven that the light crude oil conforms to the Newtonian constitutive equation. Subsequently, the momentum equation of crude oil flowing in the pipeline and fluid–solid coupling heat transfer equations were established and solved using the finite difference method. The effects of the thermal recovery temperature T w , wall thickness c, and stroke time n of the rod pump on flow Q are discussed. In particular, the flow Q within 1 min first increases and then slows down with the increase in stroke time n and reaches its maximum value at n = 7 r/min. Furthermore, flow Q decreases with an increase in c but increases as T w increases; c = 1.2 cm, T w = 363 K is the best oil recovery scheme.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940354","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

Magnetoacoustic waves in spin-1/2 dense quantum degenerate plasma: nonlinear dynamics and dissipative effects 自旋-1/2致密量子退化等离子体中的磁声波：非线性动力学和耗散效应

Zeitschrift für Naturforschung A Pub Date : 2024-05-02 DOI: 10.1515/zna-2023-0322

Mohamed Abd-Elzaher, Kottakkaran S. Nisar, Abdel-Haleem Abdel-Aty, Pralay K. Karmakar, Ahmed Atteya

{"title":"Magnetoacoustic waves in spin-1/2 dense quantum degenerate plasma: nonlinear dynamics and dissipative effects","authors":"Mohamed Abd-Elzaher, Kottakkaran S. Nisar, Abdel-Haleem Abdel-Aty, Pralay K. Karmakar, Ahmed Atteya","doi":"10.1515/zna-2023-0322","DOIUrl":"https://doi.org/10.1515/zna-2023-0322","url":null,"abstract":"Within the confines of a two-fluid quantum magnetohydrodynamic model, the investigation of magnetoacoustic shock and solitary waves is conducted in an electron-ion magnetoplasma that considers electrons of spin 1/2. When the plasma system is nonlinearly investigated using the reductive perturbation approach, the Korteweg de Vries-Burgers (KdVB) equation is produced. Sagdeev’s potential is created, revealing the presence of solitary solutions. However, when dissipative terms are included, intriguing physical solutions can be obtained. The KdVB equation is further investigated using the phase plane theory of a planar dynamical system to demonstrate the existence of periodic and solitary wave solutions. Predicting several classes of traveling wave solutions is advantageous due to various phase orbits, which manifest as soliton-shock waves, and oscillatory shock waves. The presence of a magnetic field, the density of electrons and ions, and the kinematic viscosity significantly alter the properties of magnetoacoustic solitary and shock waves. Additionally, electric fields have been identified. The outcomes obtained here can be applied to studying the nature of magnetoacoustic waves that are observed in compact astrophysical environments, where the influence of quantum spin phenomena remains significant, and also in controlled laboratory plasma experiments.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140833776","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

Dust magnetoacoustic waves in an inhomogeneous cylindrical four-component dusty plasma in the presence of polarization force 存在极化力的非均质圆柱形四分量尘埃等离子体中的尘埃磁声波

Zeitschrift für Naturforschung A Pub Date : 2024-04-27 DOI: 10.1515/zna-2024-0047

Sarit Maitra, Chitrita Dasgupta

{"title":"Dust magnetoacoustic waves in an inhomogeneous cylindrical four-component dusty plasma in the presence of polarization force","authors":"Sarit Maitra, Chitrita Dasgupta","doi":"10.1515/zna-2024-0047","DOIUrl":"https://doi.org/10.1515/zna-2024-0047","url":null,"abstract":"Dust magnetoacoustic waves have been examined in an inhomogeneous, bounded, cylindrical dusty plasma containing oppositely polarized dust particles. Considering polarization force, dust dynamics in r − θ plane is studied in the presence of inhomogeneous external magnetic field along z axis. At equilibrium, the dusty plasma components are supposed to follow Gaussian density distribution. Using reductive perturbation method (RPM), a variable coefficient cylindrical Kadomtsev–Petviashvili (VCCKP) equation has been derived. For weak azimuthal perturbation, an analytical solution, obtained by Zhang (“Exact solutions of a kdv equation with variable coefficients via exp-function method,” Nonlinear Dynam., vol. 52, nos. 1–2, pp. 11–17, 2008) using Exp-function method, is chosen. Phase velocity of dust magnetoacoustic wave is found to be modified by the density inhomogeneities, polarization force, dust charge state ratio and ion-to-electron temperature ratio. Spatio-temporal evolution of the dust number densities has been noticed. Existence of the compressive electromagnetic solitary waves is observed numerically for the chosen dusty plasma parameter range. The impacts of the inhomogeneity, polarization force, dust charge state ratio and ion-to-electron temperature ratio on the relative amplitude of the dust magnetoacoustic wave are also discussed.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140812578","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

Structural, band profiles and optical reflectivity studies of ALi2B (A = Cu, Ag; B = Ge, Sn, Pb) compounds ALi2B（A = 铜、银；B = Ge、锡、铅）化合物的结构、能带剖面和光学反射率研究

Zeitschrift für Naturforschung A Pub Date : 2024-04-27 DOI: 10.1515/zna-2023-0268

Maryam Ayaz, Hilal Khan, Hessa A. Alsalmah, Muhammad Yunas, Ghulam Murtaza

{"title":"Structural, band profiles and optical reflectivity studies of ALi2B (A = Cu, Ag; B = Ge, Sn, Pb) compounds","authors":"Maryam Ayaz, Hilal Khan, Hessa A. Alsalmah, Muhammad Yunas, Ghulam Murtaza","doi":"10.1515/zna-2023-0268","DOIUrl":"https://doi.org/10.1515/zna-2023-0268","url":null,"abstract":"The subject of given project is to highlight the basic elastic, electronic and optical reflectivity of ALi2B (A = Cu, Ag; B = Ge, Sn, Pb). For the calculation of these properties, we used the full potential linearized augmented plane wave (FP-LAPW) procedures carry through Wien2k package. Specifically, the Perdew, Burke and Ernzerhof’s generalized gradient approximation (PBE-GGA) and Wu and Cohen generalized gradient approximation (WC-GGA) have been used. The obtained results fit well with existing experimental data. Different elastic parameters, such as constant of elasticity, elastic moduli, Poisson’s ratio, anisotropy factor and Cauchy pressure, are calculated for the first time for the compounds. The elastic properties clearly summarized the compound’s elastically stability and brittleness in both zinc blend phase. The band structure results for ALi2B shows that the compounds are metallic having overlapping bands across the electron chemical potential. The valance band highest energy state is composed from combination of Cu-d and Sn-p state, disclosed through these compound’s total (DOS) plots, whereas the conduction band primarily constitution is from Li-p, Sn-s Cu-s and Sn-p states. The intraband transitions play vital rule in the description of the optical reflectivity of the ALi2B compounds.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140812902","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 stability analysis of a restrained FG nanobeam in an elastic matrix with neutral axis effects 带中轴效应的弹性基体中受约束 FG 纳米梁的稳定性分析

Zeitschrift für Naturforschung A Pub Date : 2024-04-17 DOI: 10.1515/zna-2023-0361

Ömer Civalek, Büşra Uzun, Mustafa Özgür Yaylı

{"title":"On the stability analysis of a restrained FG nanobeam in an elastic matrix with neutral axis effects","authors":"Ömer Civalek, Büşra Uzun, Mustafa Özgür Yaylı","doi":"10.1515/zna-2023-0361","DOIUrl":"https://doi.org/10.1515/zna-2023-0361","url":null,"abstract":"In this work, a general eigenvalue solution of an arbitrarily constrained nonlocal strain gradient nanobeam made of functionally graded material is presented for the first time for the stability response by the effect of the Winkler foundation. Elastic springs at the ends of the nanobeam are considered in the formulation, which have not been considered in most studies. In order to analyze deformable boundary conditions, linear equation systems are derived in terms of infinite power series by using the Fourier sine series together with the Stokes’ transform. The higher-order force boundary conditions are used to obtain a coefficient matrix including different end conditions, power-law index, elastic medium, and small-scale parameters. A general eigenvalue problem of technical interest, associated with nonlocal strain gradient theory, is mathematically evaluated and presented in detail. Parametric results are obtained to investigate the effects of material length scale parameter, Winkler stiffness, power-law index, nonlocal parameter, and elastic springs at the ends. In addition, the effects of the other higher-order elasticity theories simplified from nonlocal strain gradient theory are also investigated and some benchmark results are presented.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140610549","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

Chirped optical solitons for the complex Ginzburg–Landau equation with Hamiltonian perturbations and Kerr law nonlinearity 具有哈密顿扰动和克尔定律非线性的复杂金兹堡-朗道方程的啁啾光学孤子

Zeitschrift für Naturforschung A Pub Date : 2024-04-15 DOI: 10.1515/zna-2023-0356

Ming-Yue Tang, Tong-Yu Meng

引用次数: 0

On the validity of the exchange principle in rotatory electrothermoconvection 论旋转电热对流中交换原理的有效性

Zeitschrift für Naturforschung A Pub Date : 2024-04-13 DOI: 10.1515/zna-2023-0330

Chitresh Kumari, Jitender Kumar, Jyoti Prakash

引用次数: 0

On some novel solitonic structures for the Zhiber–Shabat model in modern physics 论现代物理学中齐伯-沙巴特模型的一些新型孤子结构

Zeitschrift für Naturforschung A Pub Date : 2024-04-08 DOI: 10.1515/zna-2024-0010

Reem K. Alhefthi, Kalim U. Tariq, Ahmet Bekir, Arslan Ahmed

{"title":"On some novel solitonic structures for the Zhiber–Shabat model in modern physics","authors":"Reem K. Alhefthi, Kalim U. Tariq, Ahmet Bekir, Arslan Ahmed","doi":"10.1515/zna-2024-0010","DOIUrl":"https://doi.org/10.1515/zna-2024-0010","url":null,"abstract":"In this article, the modified Kudryashov and extended simple equation methods are employed to obtain analytical solutions for the Zhiber–Shabat problem. The outcomes of this study clearly indicate that the provided methodologies are appropriate techniques for generating some new exact solutions for nonlinear evolution equations. Furthermore, the nature of the solutions would be presented in three dimensions for various parameters applying the most advanced scientific instruments. The physical behavior of the solutions are graphically displayed, and it is established that the acquired solutions are newly constructed in the form of bright, dark, optical, singular, and bell-shaped periodic soliton wave structures. The properties of the nonlinear model have been illustrated using 3D, 2D, and contour plots by selecting an appropriate set of parameters, which is demonstrated to visualize the physical structures more productively. Finally, it is concluded that similar strategies can also be implemented to study many contemporary models. To the best of our knowledge, the current work presents a novel case study that has not been previously studied in order to generate several new solutions to the governing model appearing in diverse disciplines. The results show that the strategies that have been employed are more effective and capable than the traditional methods found in previous research.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140603207","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

Tailoring reduced graphene oxide into nanofibrous architectures: fabrication, characterization, and functional insights 将还原氧化石墨烯裁剪成纳米纤维结构：制造、表征和功能见解

Zeitschrift für Naturforschung A Pub Date : 2024-03-25 DOI: 10.1515/zna-2023-0310

Jawaria Rehman, Nadia Anwar, Muqarrab Ahmed, Shaheen Irfan, Ghazi Aman Nowsherwan, Abdul Waheed Anwar, Nazia Iram, Javeria Arshad, Nosheen Mushahid, Ayesha Saleem

{"title":"Tailoring reduced graphene oxide into nanofibrous architectures: fabrication, characterization, and functional insights","authors":"Jawaria Rehman, Nadia Anwar, Muqarrab Ahmed, Shaheen Irfan, Ghazi Aman Nowsherwan, Abdul Waheed Anwar, Nazia Iram, Javeria Arshad, Nosheen Mushahid, Ayesha Saleem","doi":"10.1515/zna-2023-0310","DOIUrl":"https://doi.org/10.1515/zna-2023-0310","url":null,"abstract":"The electrospinning process allows the production of nanofibers from polymer solutions, making them suitable for various applications such as sensors, electronic devices, conductive materials, and advanced composites for high-temperature environments. In this research, polyaniline (PANI) was doped with camphor sulfonic camphor sulfonic acid (HCSA). HCSA dopant is used to modify the electrical and structural properties of polyaniline. To introduce reduced graphene oxide as a nanofiller to enhance the electrical properties of the polymer. Both the HCSA-doped PANI and HCSA-doped PANI with rGO nanofibers were electro-spun separately to create individual nanofibers. Fourier-transform infrared spectroscopy was used to investigate the chemical composition and functional groups present in the nanofibers. Field emission scanning electron microscopy was employed to study the nanofibers’ morphology, structure, and surface characteristics. Thermogravimetric analysis was used to assess the thermal stability of the nanofibers and to approximate the content of rGO. These results indicate that the addition of reduced graphene oxide (rGO) led to improvements in the nanofibers’ electrical conductivity and thermal stability.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"2018 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140301363","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