Pub Date : 2024-11-09DOI: 10.1007/s00339-024-08033-1

Zhanfeng Wang, Sai Tao, Ting Jian, Beibei Jiang

Understanding the mechanisms governing stress localization in polycrystalline materials is paramount for optimizing their mechanical properties and performance. Here, we investigate the grain boundary-induced stress localization phenomenon during compression deformation of polycrystalline 316L stainless steel through a combination of experimental and computational approaches. Utilizing a custom-built indentation setup and crystal plasticity finite element (CPFE) simulations, we elucidate the intricate interplay between microstructural features, dislocation mechanisms, and stress distribution. Experimental results reveal significant stress concentrations at grain boundaries, while CPFE simulations demonstrate the influence of grain size on stress response, with finer grains exhibiting higher stresses due to increased accumulation of geometrically necessary dislocations (GNDs). Our findings underscore the critical role of microstructural features, particularly grain boundaries and grain size, in governing the mechanical behavior of polycrystalline materials under compression loading conditions. This study provides valuable insights for designing and optimizing materials for various engineering applications.

{"title":"Grain boundary-induced stress localization during compression deformation of polycrystalline 316L stainless steel","authors":"Zhanfeng Wang, Sai Tao, Ting Jian, Beibei Jiang","doi":"10.1007/s00339-024-08033-1","DOIUrl":"10.1007/s00339-024-08033-1","url":null,"abstract":"<div><p>Understanding the mechanisms governing stress localization in polycrystalline materials is paramount for optimizing their mechanical properties and performance. Here, we investigate the grain boundary-induced stress localization phenomenon during compression deformation of polycrystalline 316L stainless steel through a combination of experimental and computational approaches. Utilizing a custom-built indentation setup and crystal plasticity finite element (CPFE) simulations, we elucidate the intricate interplay between microstructural features, dislocation mechanisms, and stress distribution. Experimental results reveal significant stress concentrations at grain boundaries, while CPFE simulations demonstrate the influence of grain size on stress response, with finer grains exhibiting higher stresses due to increased accumulation of geometrically necessary dislocations (GNDs). Our findings underscore the critical role of microstructural features, particularly grain boundaries and grain size, in governing the mechanical behavior of polycrystalline materials under compression loading conditions. This study provides valuable insights for designing and optimizing materials for various engineering applications.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1007/s12043-024-02845-9

Islam M Elbaz, M A Sohaly, H El-Metwally

Through the application of mathematical epidemiology principles, the formulation of the soft drugs model is established, and the complete dynamics of this deterministic model are contingent upon the crucial parameter called the basic reproduction number, denoted as (R_{0}^{d}). The stochastic soft drug epidemic models are developed by considering the parametric and non-parametric stochastic perturbation techniques. Dynamics of the two different stochastic models are determined using the analog stochastic thresholds (R_0^{s_{1}}), (R_0^{s_{2}}), respectively. Introducing suitable Lyapunov functionals enables us to establish sufficient axioms for the extinction and permanence of soft drug users in both deterministic and stochastic models. Moreover, the sensitivity of the deterministic and stochastic thresholds to some important parameters involved in the models is illustrated. For the verification of our theoretical results, we develop some numerical simulations using the Euler–Maruyama scheme.

{"title":"Soft drug epidemic in deterministic and stochastic case studies","authors":"Islam M Elbaz, M A Sohaly, H El-Metwally","doi":"10.1007/s12043-024-02845-9","DOIUrl":"10.1007/s12043-024-02845-9","url":null,"abstract":"<div><p>Through the application of mathematical epidemiology principles, the formulation of the soft drugs model is established, and the complete dynamics of this deterministic model are contingent upon the crucial parameter called the basic reproduction number, denoted as <span>(R_{0}^{d})</span>. The stochastic soft drug epidemic models are developed by considering the parametric and non-parametric stochastic perturbation techniques. Dynamics of the two different stochastic models are determined using the analog stochastic thresholds <span>(R_0^{s_{1}})</span>, <span>(R_0^{s_{2}})</span>, respectively. Introducing suitable Lyapunov functionals enables us to establish sufficient axioms for the extinction and permanence of soft drug users in both deterministic and stochastic models. Moreover, the sensitivity of the deterministic and stochastic thresholds to some important parameters involved in the models is illustrated. For the verification of our theoretical results, we develop some numerical simulations using the Euler–Maruyama scheme.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1007/s12043-024-02846-8

Kiran Pant, Pratibha Fuloria

The present investigation examines the behaviour of compact relativistic objects characterised by static and spherically symmetric space–time for neutral anisotropic matter distribution. More specifically, we consider an equation of state (EoS), in which density and radial pressure are connected with each other quadratically. By smoothly matching the interior space–time with the exterior at the stellar surface, the appropriate values of the constant parameters for physically realistic solutions are obtained to model various compact stars. We explore the physical behaviour of compact stellar models SMC X-4, Vela X-1, CEN X-3, PSR J1614-2230, LMC X-4 and EXO 1785-248. Further, we describe several features of the compact stellar systems that exhibit physically acceptable attributes with no singularity. All important stability criteria, such as the energy conditions, causality conditions, Buchdhal condition and the adiabatic index are fulfilled by our neutral anisotropic compact star models. An in-depth comprehension of the physical characteristics of the proposed solution has been achieved through meticulous analytical and graphical examinations. By utilising this solution, the masses and radii of six compact stellar candidates mentioned above are optimised with the observed values obtained experimentally. The derived solution might be useful to enhance the understanding of the strong-field regimes and self-gravitating entities.

{"title":"A comprehensive analysis of anisotropic stellar objects with quadratic equation of state","authors":"Kiran Pant, Pratibha Fuloria","doi":"10.1007/s12043-024-02846-8","DOIUrl":"10.1007/s12043-024-02846-8","url":null,"abstract":"<div><p>The present investigation examines the behaviour of compact relativistic objects characterised by static and spherically symmetric space–time for neutral anisotropic matter distribution. More specifically, we consider an equation of state (EoS), in which density and radial pressure are connected with each other quadratically. By smoothly matching the interior space–time with the exterior at the stellar surface, the appropriate values of the constant parameters for physically realistic solutions are obtained to model various compact stars. We explore the physical behaviour of compact stellar models SMC X-4, Vela X-1, CEN X-3, PSR J1614-2230, LMC X-4 and EXO 1785-248. Further, we describe several features of the compact stellar systems that exhibit physically acceptable attributes with no singularity. All important stability criteria, such as the energy conditions, causality conditions, Buchdhal condition and the adiabatic index are fulfilled by our neutral anisotropic compact star models. An in-depth comprehension of the physical characteristics of the proposed solution has been achieved through meticulous analytical and graphical examinations. By utilising this solution, the masses and radii of six compact stellar candidates mentioned above are optimised with the observed values obtained experimentally. The derived solution might be useful to enhance the understanding of the strong-field regimes and self-gravitating entities.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1007/s12043-024-02840-0

Gopinath Mandal, Dulal Pal

The main aim of this investigation is to study the heat transport and entropy generation of human blood as a hybrid nanofluid (HNF) containing gold (Au) and silver (Ag) nanoparticles inside a Darcy–Fochheimer porous stenotic artery in the presence of thermal radiation and magnetic field. The primary reason for adopting Au and Ag nanoparticles as nanomaterials for drug delivery is because they exhibit potential drug transport and imaging properties for treating stenosed artery. Furthermore, velocity slip and convective boundary conditions at the surface of the artery are considered in this study. A method of suitable similarity transformations has been utilised to convert the partial differential equations (PDEs) into dimensionless ordinary differential equations (ODEs) and using the bvp4c built-in solver in MATLAB mathematical software, numerical solutions have been obtained. The plots of the results show that the hybrid nanofluid (Au–Ag/blood) has greater thermal conductance than the normal nanofluid (Au/blood). The temperature and velocity of the blood gradually increase as the percentage of nanoparticles in the blood flow grows. The heat transference rate increases with increase in Biot number (Bi) and radiation (Nr) effect, which helps in removing the toxic plaque from the artery. Due to the contraction of the artery, dual solutions are found, but dual solutions cannot be found beyond the critical values of suction (S) and shrinking ((lambda )) parameters. The critical values (S_C) from computation are 1.5851, 1.5949 and critical values (lambda _C) are 0.652, 0.781 for Au/blood nanofluid (NF) and Au–Ag/blood hybrid nanofluid (HNF), respectively. Also, the stability of blood flow is achieved by finding the lowest eigenvalue. A positive minimum eigenvalue ((beta _1)) denotes the upper stable solution branch, whereas a negative minimal eigenvalue indicates the bottom unstable solution branch. The entropy of the blood as the HNF flow was found to increase with nanoparticle volume fraction ((phi _1, phi _2)), porous parameter (P) and magnetic parameter (M). These results will help greatly to avoid brain stroke or heart attack caused by the burst of an artery.

{"title":"Impact of gold and silver nanoparticles on the thermally radiating MHD slip blood flow within the stenotic artery using stability analysis and entropy optimisation","authors":"Gopinath Mandal, Dulal Pal","doi":"10.1007/s12043-024-02840-0","DOIUrl":"10.1007/s12043-024-02840-0","url":null,"abstract":"<div><p>The main aim of this investigation is to study the heat transport and entropy generation of human blood as a hybrid nanofluid (HNF) containing gold (Au) and silver (Ag) nanoparticles inside a Darcy–Fochheimer porous stenotic artery in the presence of thermal radiation and magnetic field. The primary reason for adopting Au and Ag nanoparticles as nanomaterials for drug delivery is because they exhibit potential drug transport and imaging properties for treating stenosed artery. Furthermore, velocity slip and convective boundary conditions at the surface of the artery are considered in this study. A method of suitable similarity transformations has been utilised to convert the partial differential equations (PDEs) into dimensionless ordinary differential equations (ODEs) and using the bvp4c built-in solver in MATLAB mathematical software, numerical solutions have been obtained. The plots of the results show that the hybrid nanofluid (Au–Ag/blood) has greater thermal conductance than the normal nanofluid (Au/blood). The temperature and velocity of the blood gradually increase as the percentage of nanoparticles in the blood flow grows. The heat transference rate increases with increase in Biot number (<i>Bi</i>) and radiation (<i>Nr</i>) effect, which helps in removing the toxic plaque from the artery. Due to the contraction of the artery, dual solutions are found, but dual solutions cannot be found beyond the critical values of suction (<i>S</i>) and shrinking (<span>(lambda )</span>) parameters. The critical values <span>(S_C)</span> from computation are 1.5851, 1.5949 and critical values <span>(lambda _C)</span> are 0.652, 0.781 for Au/blood nanofluid (NF) and Au–Ag/blood hybrid nanofluid (HNF), respectively. Also, the stability of blood flow is achieved by finding the lowest eigenvalue. A positive minimum eigenvalue (<span>(beta _1)</span>) denotes the upper stable solution branch, whereas a negative minimal eigenvalue indicates the bottom unstable solution branch. The entropy of the blood as the HNF flow was found to increase with nanoparticle volume fraction (<span>(phi _1, phi _2)</span>), porous parameter (<i>P</i>) and magnetic parameter (<i>M</i>). These results will help greatly to avoid brain stroke or heart attack caused by the burst of an artery.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1007/s12043-024-02836-w

Kotha Gangadhar, T Sujana Sree, Abderrahim Wakif, K Subbarao

The present investigation of the rotating disk system is highly significant due to its many applications, such as in fluid thermal reactors, regulating fluidic systems and fluid stirring. Subject to the upper functions of the rotating disk, the Stefan blowing into the three-dimensional Reiner–Rivlin (R–R) fluid flow by the rotating disk affect the vertical direction. Thermal radiation and Cattaneo–Christov (CC) energy diffusion effects are examined into considering energy transport. The chemical reaction is accommodated in the concentration equation. The convective boundary conditions are considered in the disk surfaces. The ensuing nonlinear systems are determined by applying the Bvp4c routine along with the shooting method. The obtained outcomes are shown graphically with physical justification. The results show that R–R parameters cause a downturn in the radial and tangential velocity profiles as well as the temperature field. The curves of the temperature profile enhance with higher values of radiation parameter. Although this radiation falls onto the fluid surface and increases the temperature of the liquid as hot particles collide with cold particles, the skin friction coefficients decrease with suction. However, the heat and mass transfer rates are enhanced. The current model has been validated by comparing the simplified version of the investigation to a previously published article and a close agreement has been found.

{"title":"Stefan blowing impact and chemical response of Rivlin–Reiner fluid through rotating convective disk","authors":"Kotha Gangadhar, T Sujana Sree, Abderrahim Wakif, K Subbarao","doi":"10.1007/s12043-024-02836-w","DOIUrl":"10.1007/s12043-024-02836-w","url":null,"abstract":"<div><p>The present investigation of the rotating disk system is highly significant due to its many applications, such as in fluid thermal reactors, regulating fluidic systems and fluid stirring. Subject to the upper functions of the rotating disk, the Stefan blowing into the three-dimensional Reiner–Rivlin (R–R) fluid flow by the rotating disk affect the vertical direction. Thermal radiation and Cattaneo–Christov (CC) energy diffusion effects are examined into considering energy transport. The chemical reaction is accommodated in the concentration equation. The convective boundary conditions are considered in the disk surfaces. The ensuing nonlinear systems are determined by applying the Bvp4c routine along with the shooting method. The obtained outcomes are shown graphically with physical justification. The results show that R–R parameters cause a downturn in the radial and tangential velocity profiles as well as the temperature field. The curves of the temperature profile enhance with higher values of radiation parameter. Although this radiation falls onto the fluid surface and increases the temperature of the liquid as hot particles collide with cold particles, the skin friction coefficients decrease with suction. However, the heat and mass transfer rates are enhanced. The current model has been validated by comparing the simplified version of the investigation to a previously published article and a close agreement has been found.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1140/epja/s10050-024-01436-x

Prasanna M., V. V. Parkar, V. Jha, S. K. Pandit, A. Parmar, A. Shrivastava, K. Mahata, K. Ramachandran, R. Palit, Bhushan Kanagalekar, B. G. Hegde

Neutron transfer cross sections for ^{7}Li+^{205}Tl system were measured near Coulomb barrier energies using online (gamma )-ray detection technique. One neutron stripping, two neutron stripping, and one neutron pickup cross sections have been extracted and are compared with the Coupled Reaction Channel (CRC) calculations. The systematics of one and two neutron stripping and pickup cross sections with a ^{7}Li projectile on several targets show an approximate universal behaviour. A comparison of integrated neutron transfer cross sections with complete and incomplete fusion cross sections available with ^{7}Li projectile is presented to understand the systematic behaviour. The neutron transfer along with cumulative sum of complete and incomplete fusion was found to explain the estimated reaction cross section in ^{7}Li+^{205}Tl system.

{"title":"Neutron transfer in 7Li+205Tl system","authors":"Prasanna M., V. V. Parkar, V. Jha, S. K. Pandit, A. Parmar, A. Shrivastava, K. Mahata, K. Ramachandran, R. Palit, Bhushan Kanagalekar, B. G. Hegde","doi":"10.1140/epja/s10050-024-01436-x","DOIUrl":"10.1140/epja/s10050-024-01436-x","url":null,"abstract":"<div><p>Neutron transfer cross sections for <sup>7</sup>Li+<sup>205</sup>Tl system were measured near Coulomb barrier energies using online <span>(gamma )</span>-ray detection technique. One neutron stripping, two neutron stripping, and one neutron pickup cross sections have been extracted and are compared with the Coupled Reaction Channel (CRC) calculations. The systematics of one and two neutron stripping and pickup cross sections with a <sup>7</sup>Li projectile on several targets show an approximate universal behaviour. A comparison of integrated neutron transfer cross sections with complete and incomplete fusion cross sections available with <sup>7</sup>Li projectile is presented to understand the systematic behaviour. The neutron transfer along with cumulative sum of complete and incomplete fusion was found to explain the estimated reaction cross section in <sup>7</sup>Li+<sup>205</sup>Tl system.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-024-01436-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1140/epja/s10050-024-01423-2

Andrei Butuza

For the even nuclei of (^{204-208})Rn, (^{214-218})Ra and (^{232-234})U, the simultaneous description of charge distribution and total kinetic energy are studied within the scission-point model. The calculated data are compared with experimental data from the literature. Correlations between these observables and other quantities of interest are analysed.

对于 Rn、Ra 和 U 的偶核，在裂变点模型中研究了电荷分布和总动能的同步描述。计算数据与文献中的实验数据进行了比较。分析了这些观测值与其他相关量之间的相关性。

{"title":"Charge distribution and total kinetic energy in the fission of Rn, Ra and U","authors":"Andrei Butuza","doi":"10.1140/epja/s10050-024-01423-2","DOIUrl":"10.1140/epja/s10050-024-01423-2","url":null,"abstract":"<div><p>For the even nuclei of <span>(^{204-208})</span>Rn, <span>(^{214-218})</span>Ra and <span>(^{232-234})</span>U, the simultaneous description of charge distribution and total kinetic energy are studied within the scission-point model. The calculated data are compared with experimental data from the literature. Correlations between these observables and other quantities of interest are analysed.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-024-01423-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-09DOI: 10.1007/s12043-024-02834-y

Abha Kumari, Rajat Tripathi, Amit Kumar

The motion of a long, axisymmetric bubble (fluid 1) inside a vertical peristaltic conduit containing a self-rewetting fluid (fluid 2) is discussed in this article. The fluid inside the tube and the floating bubble are immiscible, incompressible and have different densities. The peristaltic channel has two open ends. It is assumed that the bubble can move freely inside the tube without being restricted or deformed by the border wall. The effect of the density difference between the two fluids, Marangoni convection caused by the thermal and solutal gradient and an imposed back flow on the position and shape of the bubble have all been discussed. Motion of the bubble within a peristaltic tube, influenced by the Marangoni convection due to thermal and solutal gradients, has find various applications in the electrification of the atmosphere by sea bubbles, efficient mixing in microfluidic devices, improved cooling in heat exchangers, design of hydrophobic surfaces, spray coating thography techniques, enhanced mass transfer in chemical reactors, advancing various industrial and biomedical applications with precise fluid control. A mathematical model of the problem has been developed using a two-dimensional cylindrical polar coordinate system. The governing equations are in the form of linear partial differential equation and have been solved analytically. The effect of the thermo-solutal Marangoni convection in the microgravity region and the imposed back flow, impact of gravity-driven convection in the absence of the Marangoni convection or back flow, on the motion of bubble are discussed by plotting the position of the bubble. The initial radius and thermo-solutal Marangoni convection determine the bubble’s form as it evolves. When the initial radius falls below a critical value, the bubble becomes broader and shorter; conversely, when the original radius exceeds the crucial value, the bubble becomes longer and thinner.

{"title":"Study of the bubble motion inside a peristaltic tube","authors":"Abha Kumari, Rajat Tripathi, Amit Kumar","doi":"10.1007/s12043-024-02834-y","DOIUrl":"10.1007/s12043-024-02834-y","url":null,"abstract":"<div><p>The motion of a long, axisymmetric bubble (fluid 1) inside a vertical peristaltic conduit containing a self-rewetting fluid (fluid 2) is discussed in this article. The fluid inside the tube and the floating bubble are immiscible, incompressible and have different densities. The peristaltic channel has two open ends. It is assumed that the bubble can move freely inside the tube without being restricted or deformed by the border wall. The effect of the density difference between the two fluids, Marangoni convection caused by the thermal and solutal gradient and an imposed back flow on the position and shape of the bubble have all been discussed. Motion of the bubble within a peristaltic tube, influenced by the Marangoni convection due to thermal and solutal gradients, has find various applications in the electrification of the atmosphere by sea bubbles, efficient mixing in microfluidic devices, improved cooling in heat exchangers, design of hydrophobic surfaces, spray coating thography techniques, enhanced mass transfer in chemical reactors, advancing various industrial and biomedical applications with precise fluid control. A mathematical model of the problem has been developed using a two-dimensional cylindrical polar coordinate system. The governing equations are in the form of linear partial differential equation and have been solved analytically. The effect of the thermo-solutal Marangoni convection in the microgravity region and the imposed back flow, impact of gravity-driven convection in the absence of the Marangoni convection or back flow, on the motion of bubble are discussed by plotting the position of the bubble. The initial radius and thermo-solutal Marangoni convection determine the bubble’s form as it evolves. When the initial radius falls below a critical value, the bubble becomes broader and shorter; conversely, when the original radius exceeds the crucial value, the bubble becomes longer and thinner.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-08DOI: 10.1007/s00339-024-08027-z

G. M. Sravani, N. Murali, B. Chandra Sekhar, P. S. V. Shanmukhi, Jasgurpreet Singh Chohan, Tulu Wegayehu Mammo, D. Parajuli, Khalid Mujasam Batoo, Muhammad Farzik Ijaz, K. Samatha

{"title":"Correction: Synthesis, structural, improved magnetic and electrical properties of Sr2+ doped BiFeO3 multiferroic materials","authors":"G. M. Sravani, N. Murali, B. Chandra Sekhar, P. S. V. Shanmukhi, Jasgurpreet Singh Chohan, Tulu Wegayehu Mammo, D. Parajuli, Khalid Mujasam Batoo, Muhammad Farzik Ijaz, K. Samatha","doi":"10.1007/s00339-024-08027-z","DOIUrl":"10.1007/s00339-024-08027-z","url":null,"abstract":"","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

Pub Date : 2024-11-08DOI: 10.1007/s00340-024-08354-2

Yuanhao Du, Hui Feng, Shuai Wu

In this study, we report a three-dimensional synthetic aperture imaging system realized by a terahertz time-domain spectrometer. The temporal waveforms of the terahertz pulses scattered by the object to be imaged are Fourier transformed to the frequency domain before image reconstruction by the back-projection algorithm. The resolution of the imaging system is close to the center wavelength of the terahertz pulses, as tested by a resolution test chart. We also demonstrate the ability of this imaging method in non-destructive evaluation applications by measuring the internal structures of a university badge. A three-dimensional terahertz image and a series of slice views of the badge are acquired. The terahertz images clearly show the surface shape and internal structures of the badge, and the logo of the university on the badge is successfully extracted from the three-dimensional terahertz image.

{"title":"Synthetic aperture imaging with pulsed terahertz waves and its application in three-dimensional modeling of complex structures","authors":"Yuanhao Du, Hui Feng, Shuai Wu","doi":"10.1007/s00340-024-08354-2","DOIUrl":"10.1007/s00340-024-08354-2","url":null,"abstract":"<div><p>In this study, we report a three-dimensional synthetic aperture imaging system realized by a terahertz time-domain spectrometer. The temporal waveforms of the terahertz pulses scattered by the object to be imaged are Fourier transformed to the frequency domain before image reconstruction by the back-projection algorithm. The resolution of the imaging system is close to the center wavelength of the terahertz pulses, as tested by a resolution test chart. We also demonstrate the ability of this imaging method in non-destructive evaluation applications by measuring the internal structures of a university badge. A three-dimensional terahertz image and a series of slice views of the badge are acquired. The terahertz images clearly show the surface shape and internal structures of the badge, and the logo of the university on the badge is successfully extracted from the three-dimensional terahertz image.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}