Abstract In this article, a method called characteristic decomposition is used to show the presence of simple waves for the two-dimensional compressible flow in a non-ideal magneto-hydrodynamics system. Here, a steady and pseudo-steady state magneto-hydrodynamics system is considered, and we provide a characteristic decomposition of the flow equations in both systems. This decomposition ensures the presence of a simple wave adjacent to a region of constant state for the system under consideration. Further, this result is extended as an application of the characteristic decomposition in a pseudo-steady state, and we prove the existence of a simple wave in a full magneto-hydrodynamics system by taking the vorticity and the entropy to be constant along the pseudo-flow characteristics. These results extend the fundamental theorem proposed by Courant and Friedrichs for a reducible system (R. Courant and K. O. Friedrichs, Supersonic Flow and Shock Waves, New York, Interscience Publishers, Inc., 1948, p. 464). A motivational work was carried out for an ideal gas by Li et al. (“Simple waves and a characteristic decomposition of the two dimensional compressible Euler equations,” Commun. Math. Phys. Math. Phys., vol. 267, no. 1, pp. 1–12, 2006) and for a non-ideal gas by Zafar and Sharma (“Characteristic decomposition of compressible Euler equations for a non-ideal gas in two-dimensions,” J. Math. Phys., vol. 55, no. 9, pp. 093103–093112, 2014], [M. Zafar, “A note on characteristic decomposition for two-dimensional euler system in van der waals fluids,” Int. J. Non-Linear Mech., vol. 86, pp. 33–36, 2016].
摘要 本文采用一种称为特征分解的方法来说明非理想磁流体力学系统中二维可压缩流动存在简单波。本文考虑了稳态和伪稳态磁流体力学系统，并给出了这两个系统中流动方程的特征分解。这种分解确保了所考虑的系统在恒定状态区域附近存在一个简单波。此外，我们还将这一结果扩展为特征分解在伪稳态中的应用，并通过沿伪流特征将涡度和熵取为常数，证明了全磁流体力学系统中简波的存在。这些结果扩展了 Courant 和 Friedrichs 针对可还原系统提出的基本定理（R. Courant 和 K. O. Friedrichs，《超音速流和冲击波》，纽约，Interscience 出版社，1948 年，第 464 页）。Li 等人针对理想气体开展了一项激励性工作（"Simple waves and a characteristic decomposition of the two dimensional compressible Euler equations," Commun.Math.Phys.267, no. 1, pp.物理》，第 55 卷，第 9 期，第 093103-093112 页，2014 年]，[M.Zafar, "A note on characteristic decomposition for two-dimensional euler system in van der waals fluids," Int. J. Non-Linear Mech.J. Non-Linear Mech., vol. 86, pp.］
{"title":"On the existence of simple waves for two-dimensional non-ideal magneto-hydrodynamics","authors":"Gaurav, L. P. Singh","doi":"10.1515/zna-2024-0069","DOIUrl":"https://doi.org/10.1515/zna-2024-0069","url":null,"abstract":"Abstract In this article, a method called characteristic decomposition is used to show the presence of simple waves for the two-dimensional compressible flow in a non-ideal magneto-hydrodynamics system. Here, a steady and pseudo-steady state magneto-hydrodynamics system is considered, and we provide a characteristic decomposition of the flow equations in both systems. This decomposition ensures the presence of a simple wave adjacent to a region of constant state for the system under consideration. Further, this result is extended as an application of the characteristic decomposition in a pseudo-steady state, and we prove the existence of a simple wave in a full magneto-hydrodynamics system by taking the vorticity and the entropy to be constant along the pseudo-flow characteristics. These results extend the fundamental theorem proposed by Courant and Friedrichs for a reducible system (R. Courant and K. O. Friedrichs, Supersonic Flow and Shock Waves, New York, Interscience Publishers, Inc., 1948, p. 464). A motivational work was carried out for an ideal gas by Li et al. (“Simple waves and a characteristic decomposition of the two dimensional compressible Euler equations,” Commun. Math. Phys. Math. Phys., vol. 267, no. 1, pp. 1–12, 2006) and for a non-ideal gas by Zafar and Sharma (“Characteristic decomposition of compressible Euler equations for a non-ideal gas in two-dimensions,” J. Math. Phys., vol. 55, no. 9, pp. 093103–093112, 2014], [M. Zafar, “A note on characteristic decomposition for two-dimensional euler system in van der waals fluids,” Int. J. Non-Linear Mech., vol. 86, pp. 33–36, 2016].","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"117 50","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141666559","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}
This article relates with the interaction of water waves obliquely incident on a semi-infinite submerged elastic plate of insignificant thickness. The solution is obtained using method of mode matching. Reflection coefficients under the variation of various physical parameters: submergence depth, angle of incidence, stiffness of elastic plate and Poisson’s ratio, for two different edge conditions (i) pinned edge condition and (ii) sliding edge condition are discussed. Convergence and validation of results is also given. Behaviour of the velocity potentials around semi-infinite submerged elastic plate for different physical parameters are also analyzed. The consequences are explained through numerical and graphical results. More over energy balance relation is also discussed.
{"title":"On oblique interaction of water waves with semi-infinite submerged elastic plate","authors":"Tooba Mirza, Mahmood-ul Hassan, R. Nawaz","doi":"10.1515/zna-2024-0026","DOIUrl":"https://doi.org/10.1515/zna-2024-0026","url":null,"abstract":"This article relates with the interaction of water waves obliquely incident on a semi-infinite submerged elastic plate of insignificant thickness. The solution is obtained using method of mode matching. Reflection coefficients under the variation of various physical parameters: submergence depth, angle of incidence, stiffness of elastic plate and Poisson’s ratio, for two different edge conditions (i) pinned edge condition and (ii) sliding edge condition are discussed. Convergence and validation of results is also given. Behaviour of the velocity potentials around semi-infinite submerged elastic plate for different physical parameters are also analyzed. The consequences are explained through numerical and graphical results. More over energy balance relation is also discussed.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504049","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}
In a recent study, we proposed an axion-electrodynamics model that consistently incorporates a lepton Dirac field into the gauge-invariant Lagrangian of a closed physical system. Our investigation delved toward potential applications of the model, with a focus on its implications in the realm of Dark Matter axions interacting with leptons in a nonlinear electrodynamics background. In the present work, we introduce an extended axion-electrodynamics model wherein the Bianchi identities are modified by the axion field. This leads to a modification of the energy conservation law for the fields: the Poynting theorem in a source-free region, in which the axion field is involved. By implementing a quantization scheme, our model can offer a novel approach for addressing the problem of axion production/conversion in the presence of electromagnetic and Dirac fields.
{"title":"Axion-electrodynamics and the Poynting theorem","authors":"Stanley A. Bruce","doi":"10.1515/zna-2024-0055","DOIUrl":"https://doi.org/10.1515/zna-2024-0055","url":null,"abstract":"\u0000 In a recent study, we proposed an axion-electrodynamics model that consistently incorporates a lepton Dirac field into the gauge-invariant Lagrangian of a closed physical system. Our investigation delved toward potential applications of the model, with a focus on its implications in the realm of Dark Matter axions interacting with leptons in a nonlinear electrodynamics background. In the present work, we introduce an extended axion-electrodynamics model wherein the Bianchi identities are modified by the axion field. This leads to a modification of the energy conservation law for the fields: the Poynting theorem in a source-free region, in which the axion field is involved. By implementing a quantization scheme, our model can offer a novel approach for addressing the problem of axion production/conversion in the presence of electromagnetic and Dirac fields.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141267089","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}
This article proposes a compact coplanar waveguide (CPW)-fed antenna to improve proposed antenna’s bandwidth without altering its basic design. The proposed fractal shaped antenna comprises a CPW feed with a defective ground structure (DGS). The proposed antenna is operating at single frequency band (C), when the gap between two glass plates is filled with an air and covers two different frequency bands (S and C), when there is a LC material p-methoxy-benzylidene-p-n-butyl aniline (MBBA) with ZnO nanoparticles, further the proposed fractal antenna, resonating from 4.4 to 6 GHz frequency and offers 5.64 dBi peak gain with air gap and operates from 3.1 GHz to 6.8 GHz with a maximum obtained peak gain of 3.9 dBi when filled with MBBA dispersed with ZnO nano particles. IT also evident that the transition temperatures of pure MBBA are reduced when doped with ZnO nano particles. The results are compared and analyzed with the body of data available.
{"title":"Design of fractal shaped antenna with MBBA LC material dispersed with ZnO nanoparticles for bandwidth improvement","authors":"Nagandla Prasad, Pokkunuri Pardhasaradhi, Boddapati Taraka Phani Madhav, Gorla Venkata Ganesh, Velichalamala Sidda Reddy, Manepalli Rama Krishna Nanchara Rao, Nutakki Krishna Mohan","doi":"10.1515/zna-2024-0061","DOIUrl":"https://doi.org/10.1515/zna-2024-0061","url":null,"abstract":"This article proposes a compact coplanar waveguide (CPW)-fed antenna to improve proposed antenna’s bandwidth without altering its basic design. The proposed fractal shaped antenna comprises a CPW feed with a defective ground structure (DGS). The proposed antenna is operating at single frequency band (C), when the gap between two glass plates is filled with an air and covers two different frequency bands (S and C), when there is a LC material <jats:italic>p</jats:italic>-methoxy-benzylidene-<jats:italic>p</jats:italic>-<jats:italic>n</jats:italic>-butyl aniline (MBBA) with ZnO nanoparticles, further the proposed fractal antenna, resonating from 4.4 to 6 GHz frequency and offers 5.64 dBi peak gain with air gap and operates from 3.1 GHz to 6.8 GHz with a maximum obtained peak gain of 3.9 dBi when filled with MBBA dispersed with ZnO nano particles. IT also evident that the transition temperatures of pure MBBA are reduced when doped with ZnO nano particles. The results are compared and analyzed with the body of data available.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189971","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}
Fethi Madouri, Abdullah Bnyah Alanzi, Abdeldjalil Merdaci
The Pauli–Schrodinger equation for a non-relativistic position dependent mass with spin 1/2 and magnetic momentum μ0 in a generalized Morse potential and permanent magnetic field is solved using the Nikiforov–Uvarov method. The energy eigenvalues and the corresponding eigenfunctions are obtained analytically. It is also shown that the results established in a previous work appear to be a special case.
{"title":"Exact solutions of Pauli–Schrödinger equation for a particle with position dependent mass and magnetic momentum in a generalized Morse potential and magnetic field","authors":"Fethi Madouri, Abdullah Bnyah Alanzi, Abdeldjalil Merdaci","doi":"10.1515/zna-2024-0021","DOIUrl":"https://doi.org/10.1515/zna-2024-0021","url":null,"abstract":"The Pauli–Schrodinger equation for a non-relativistic position dependent mass with spin 1/2 and magnetic momentum <jats:italic>μ</jats:italic> <jats:sub>0</jats:sub> in a generalized Morse potential and permanent magnetic field is solved using the Nikiforov–Uvarov method. The energy eigenvalues and the corresponding eigenfunctions are obtained analytically. It is also shown that the results established in a previous work appear to be a special case.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141167835","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}
New transition curves from straight paths to circular paths are proposed for the first time in this study. The paths enable the vehicles to maintain constant normal acceleration components when the vehicle has a given tangential deceleration component. The differential equation describing the path for an arbitrary tangential deceleration component is given first. Several special cases corresponding to different deceleration functions in terms of velocity and position are derived. The path equations are third order ordinary differential equations with high nonlinearities. The equations are cast into a non-dimensional form which enables to define the dimensionless parameters affecting the curves. Two of the special cases are numerically treated: (1) Deceleration proportional to the velocity, (2) Deceleration exponentially decaying with path length. The effects of dimensionless parameters on the solutions are exploited in the figures. The transition curves may be employed in determining the paths of land, aerial and marine vehicles.
{"title":"New transition curves maintaining constant normal accelerations for vehicles","authors":"Mehmet Pakdemirli","doi":"10.1515/zna-2024-0052","DOIUrl":"https://doi.org/10.1515/zna-2024-0052","url":null,"abstract":"New transition curves from straight paths to circular paths are proposed for the first time in this study. The paths enable the vehicles to maintain constant normal acceleration components when the vehicle has a given tangential deceleration component. The differential equation describing the path for an arbitrary tangential deceleration component is given first. Several special cases corresponding to different deceleration functions in terms of velocity and position are derived. The path equations are third order ordinary differential equations with high nonlinearities. The equations are cast into a non-dimensional form which enables to define the dimensionless parameters affecting the curves. Two of the special cases are numerically treated: (1) Deceleration proportional to the velocity, (2) Deceleration exponentially decaying with path length. The effects of dimensionless parameters on the solutions are exploited in the figures. The transition curves may be employed in determining the paths of land, aerial and marine vehicles.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141167263","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}
Kevine Lena Nguemo Tchoupa, A. S. T. Kammogne, M. S. Siewe, Cedric Talonang Noufozo
This paper focuses on the estimation of the nonlinear encoding and responses of a photosensitive Fitz Hugh Nagumo (FHN) neuron-based-meminductor and provides a relevant analysis of its phase synchronization. In the pattern, a Fitz Hugh–Nagumo neuron connected to a meminductor is activated by a photocell, and a time-varying current source is generated by the presence of external optical signals. This coupling is a benchmark circuit with memory similar to artificial eyes with the ability to capture and encode external signals. It is designed with the aim of studying the dynamics of a neuron with a memory effect highlighted through the meminductor. An appropriate dynamical analysis is provided using standard indicators such as bifurcations to point out thorough transitions and the nature of the electrical neuronal activities. Some couplings between two FHN neurons with meminductor using hybrid synapses composed of passive electronic components are achieved. Relevant tools are used to analyze the stability of the synchronization which gives prominent details on the selection of the appropriate coupling. The energy balance of the external system is evaluated which gives the effort to achieve encoding signals and also proves the feasibility of the proposal in real-time implementation. Simulations are performed on FPGA. The results present a good agreement. In many engineering applications, the detection of optical signals is inescapable as well as the synchronization of its signals for the transmission of the stimuli. These results could be useful for the designer.
{"title":"Bifurcation investigation, phase synchronization and FPGA implementation of a new photosensitive Fitz Hugh Nagumo neuron based meminductor","authors":"Kevine Lena Nguemo Tchoupa, A. S. T. Kammogne, M. S. Siewe, Cedric Talonang Noufozo","doi":"10.1515/zna-2023-0247","DOIUrl":"https://doi.org/10.1515/zna-2023-0247","url":null,"abstract":"\u0000 This paper focuses on the estimation of the nonlinear encoding and responses of a photosensitive Fitz Hugh Nagumo (FHN) neuron-based-meminductor and provides a relevant analysis of its phase synchronization. In the pattern, a Fitz Hugh–Nagumo neuron connected to a meminductor is activated by a photocell, and a time-varying current source is generated by the presence of external optical signals. This coupling is a benchmark circuit with memory similar to artificial eyes with the ability to capture and encode external signals. It is designed with the aim of studying the dynamics of a neuron with a memory effect highlighted through the meminductor. An appropriate dynamical analysis is provided using standard indicators such as bifurcations to point out thorough transitions and the nature of the electrical neuronal activities. Some couplings between two FHN neurons with meminductor using hybrid synapses composed of passive electronic components are achieved. Relevant tools are used to analyze the stability of the synchronization which gives prominent details on the selection of the appropriate coupling. The energy balance of the external system is evaluated which gives the effort to achieve encoding signals and also proves the feasibility of the proposal in real-time implementation. Simulations are performed on FPGA. The results present a good agreement. In many engineering applications, the detection of optical signals is inescapable as well as the synchronization of its signals for the transmission of the stimuli. These results could be useful for the designer.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"11 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141114114","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}
In this paper the performance of a graphene/perovskite Schottky barrier photodetector is investigated theoretically for detecting infrared radiation within the spectral region of 7.5–10 μm. In order to increase the responsivity of the photodetector plasmon–polaritons are excited in the graphene layer within the specified spectral region with the aid of dielectric grating fabricated inside the photodetector structure. The results show that with the increase of the Fermi energy level in the graphene layer the wavelength where plasmon–polaritons are excited is shifted toward shorter wavelengths. This property enables the photodetector for tunable detection. The excitation of plasmon–polaritons localizes the infrared radiation incident on the photodetector to the graphene layer with a full width at half maximum of ≈12.6 nm. This localization increases the absorbance of the graphene layer considerably at peak detection wavelengths where plasmon–polaritons are excited, so that at peak detection wavelengths the absorbance of the graphene layer inside the photodetector is higher than 20 % while without the excitation of plasmon–polaritons the absorbance of the same layer is below 0.05 %. Due to this effect the responsivities of the photodetector at wavelengths where plasmon–polaritons are excited, increase more than 535 times relative to the case where plasmon–polaritons are not excited. Therefore the excitation of plasmon–polaritons not only increases the responsivity of the photodetector significantly but also enables the photodetector for tunable detection by varying the Fermi energy level in the graphene layer.
{"title":"Plasmonic graphene/perovskite Schottky barrier photodetector","authors":"Hadiseh Shahriyari, Naser Hatefi-Kargan, Ahmadreza Daraei","doi":"10.1515/zna-2024-0056","DOIUrl":"https://doi.org/10.1515/zna-2024-0056","url":null,"abstract":"\u0000 In this paper the performance of a graphene/perovskite Schottky barrier photodetector is investigated theoretically for detecting infrared radiation within the spectral region of 7.5–10 μm. In order to increase the responsivity of the photodetector plasmon–polaritons are excited in the graphene layer within the specified spectral region with the aid of dielectric grating fabricated inside the photodetector structure. The results show that with the increase of the Fermi energy level in the graphene layer the wavelength where plasmon–polaritons are excited is shifted toward shorter wavelengths. This property enables the photodetector for tunable detection. The excitation of plasmon–polaritons localizes the infrared radiation incident on the photodetector to the graphene layer with a full width at half maximum of ≈12.6 nm. This localization increases the absorbance of the graphene layer considerably at peak detection wavelengths where plasmon–polaritons are excited, so that at peak detection wavelengths the absorbance of the graphene layer inside the photodetector is higher than 20 % while without the excitation of plasmon–polaritons the absorbance of the same layer is below 0.05 %. Due to this effect the responsivities of the photodetector at wavelengths where plasmon–polaritons are excited, increase more than 535 times relative to the case where plasmon–polaritons are not excited. Therefore the excitation of plasmon–polaritons not only increases the responsivity of the photodetector significantly but also enables the photodetector for tunable detection by varying the Fermi energy level in the graphene layer.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"41 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140971538","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}
Ruoshi Fang, Kai Zhang, Ke Song, Yue Kai, Yong Li, B. Zheng
The study of thermoelasticity problems holds significant importance in the field of engineering. When analyzing non-Fourier thermoelastic problems, it was found that as the thermal relaxation time increases, the finite element solution will face convergence difficulties. Therefore, it is necessary to use alternative methods to solve. This paper proposes a physics-informed neural network (PINN) based on the DeepXDE deep learning library to analyze thermoelastic problems, including classical thermoelastic problems, thermoelastic coupling problems, and generalized thermoelastic problems. The loss function is constructed based on equations, initial conditions, and boundary conditions. Unlike traditional data-driven methods, this approach does not rely on known solutions. By comparing with analytical and finite element solutions, the applicability and accuracy of the deep learning method have been validated, providing new insights for the study of thermoelastic problems.
{"title":"A deep learning method for solving thermoelastic coupling problem","authors":"Ruoshi Fang, Kai Zhang, Ke Song, Yue Kai, Yong Li, B. Zheng","doi":"10.1515/zna-2024-0009","DOIUrl":"https://doi.org/10.1515/zna-2024-0009","url":null,"abstract":"\u0000 The study of thermoelasticity problems holds significant importance in the field of engineering. When analyzing non-Fourier thermoelastic problems, it was found that as the thermal relaxation time increases, the finite element solution will face convergence difficulties. Therefore, it is necessary to use alternative methods to solve. This paper proposes a physics-informed neural network (PINN) based on the DeepXDE deep learning library to analyze thermoelastic problems, including classical thermoelastic problems, thermoelastic coupling problems, and generalized thermoelastic problems. The loss function is constructed based on equations, initial conditions, and boundary conditions. Unlike traditional data-driven methods, this approach does not rely on known solutions. By comparing with analytical and finite element solutions, the applicability and accuracy of the deep learning method have been validated, providing new insights for the study of thermoelastic problems.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"130 37","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140976894","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}
Dodonea viscosa-zinc oxide (DV-ZnO) nanocomposite was synthesized and characterized using Fourier transform infrared (FTIR), thermal gravimetric method (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The most abundant compounds in the plant extract were explored using gas chromatography-mass spectrometry (GC-MS). FTIR indicated the existence of the different functional groups, XRD showed that the nanocomposite has the hexagonal wurtzite shape of ZnO nanoparticles, SEM-EDS showed a size of 50 nm, and elemental analysis depicts the existence of the different elements in the extract, which confirms, along with TGA results, the formation of DV-ZnO nanocomposite. The nanocomposite synergistic effect was examined for anticorrosion capabilities using gravimetric, electrochemical, and surface analysis methods. Both the plant extract and the nanocomposite exhibited corrosion inhibition abilities. However, the incorporation of the plant extract with ZnO increased the inhibition efficiency by 20 %. Weight loss and electrochemical methods concluded an inhibition efficiency of 80 % for DV-ZnO nanocomposite. The inhibition of the nanocomposite is due to the adsorption of the inhibitor on the carbon steel surface, which was verified using X-ray photoelectron spectroscopy and scanning electron microscopy (SEM). The adsorption was found to follow both Langmuir and Temkin isotherms. Surface examination using atomic force microscopy (AFM) found that the carbon steel surface roughness was decreased from the sample submerged in an uninhibited medium (Sa = 121.20 nm) when adding DV-ZnO nanocomposite (Sa = 22.95 nm) and DV plant extract inhibitor (Sa = 54.73 nm).
{"title":"Synergistic effect of ZnO nanocomposite of Dodonea viscosa for corrosion inhibition in saline media","authors":"Maha D. Alghamdi","doi":"10.1515/zna-2023-0339","DOIUrl":"https://doi.org/10.1515/zna-2023-0339","url":null,"abstract":"<jats:italic>Dodonea viscosa</jats:italic>-zinc oxide (DV-ZnO) nanocomposite was synthesized and characterized using Fourier transform infrared (FTIR), thermal gravimetric method (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The most abundant compounds in the plant extract were explored using gas chromatography-mass spectrometry (GC-MS). FTIR indicated the existence of the different functional groups, XRD showed that the nanocomposite has the hexagonal wurtzite shape of ZnO nanoparticles, SEM-EDS showed a size of 50 nm, and elemental analysis depicts the existence of the different elements in the extract, which confirms, along with TGA results, the formation of DV-ZnO nanocomposite. The nanocomposite synergistic effect was examined for anticorrosion capabilities using gravimetric, electrochemical, and surface analysis methods. Both the plant extract and the nanocomposite exhibited corrosion inhibition abilities. However, the incorporation of the plant extract with ZnO increased the inhibition efficiency by 20 %. Weight loss and electrochemical methods concluded an inhibition efficiency of 80 % for DV-ZnO nanocomposite. The inhibition of the nanocomposite is due to the adsorption of the inhibitor on the carbon steel surface, which was verified using X-ray photoelectron spectroscopy and scanning electron microscopy (SEM). The adsorption was found to follow both Langmuir and Temkin isotherms. Surface examination using atomic force microscopy (AFM) found that the carbon steel surface roughness was decreased from the sample submerged in an uninhibited medium (Sa = 121.20 nm) when adding DV-ZnO nanocomposite (Sa = 22.95 nm) and DV plant extract inhibitor (Sa = 54.73 nm).","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940384","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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