Pramana最新文献_第5页

Collision of shock waves in plasma medium: a travelling-wave solution 等离子体介质中激波的碰撞：行波解

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02849-5

Sherin Agnus, Rajeswari Seshadri

引用次数: 0

Quantum Langevin dynamics and long-time behaviour of two charged coupled oscillators in a common heat bath 两个带电耦合振荡器在普通热浴中的量子朗之万动力学和长时间行为

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02857-5

Koushik Mandal, Suraka Bhattacharjee

引用次数: 0

Influence of symmetry energy on electromagnetic field during heavy-ion collisions 重离子碰撞中对称能对电磁场的影响

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02860-w

Dhanpat Sharma, Suneel Kumar

{"title":"Influence of symmetry energy on electromagnetic field during heavy-ion collisions","authors":"Dhanpat Sharma, Suneel Kumar","doi":"10.1007/s12043-024-02860-w","DOIUrl":"10.1007/s12043-024-02860-w","url":null,"abstract":"<div>Heavy-ion collision simulations in intermediate energy regime using isospin quantum molecular dynamics model have been proposed as a novel means to glean information about the high density behaviour of nuclear matter. Herein, the influence of modelling the pressure gradient by changing stiffness parameter and isospin asymmetry on the dynamics of charged particles have been investigated. In this research, three different values of stiffness parameter, (gamma =) 0.66 (soft), 1 (stiff) and 2 (super-stiff), to tune the anisotropic transverse pressure gradients have been considered to explore the influence of density-dependent symmetry energy <div><div>$$begin{aligned} & E_{textrm{sym}}({rho })=E_{textrm{sym}}({rho _{0}}) bigg (frac{rho }{rho _{0}}bigg )^{gamma } end{aligned}$$</div></div>on the electromagnetic field and energy density evolution. Stiffer symmetry energy (( gamma =) 2) leads to larger pressure gradient than softer symmetry energy (( gamma =) 0.66) that drives stronger expansion resulting in higher intensity of ((eB_{y}(0, 0, 0))_{textrm{max}}) and (langle | vec {E}cdot vec {B}|rangle _{textrm{max}}). The correlation of eccentricity, nuclear stopping, centrality with the electromagnetic field and energy density have been established for different stiffness parameters. To deepen this study, the influence of isospin asymmetry (N/Z) on the time evolution of electromagnetic field has also been explored.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810966","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}

引用次数: 0

Effects of rough elements on mixing in microchannels 粗糙元素对微通道混合的影响

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02870-8

Shuai Yuan

{"title":"Effects of rough elements on mixing in microchannels","authors":"Shuai Yuan","doi":"10.1007/s12043-024-02870-8","DOIUrl":"10.1007/s12043-024-02870-8","url":null,"abstract":"<div>For incompressible fluids, no discernible differences exist between microscale and macroscale flows. However, surface roughness has emerged as a significant factor influencing mass transport phenomena at the microscale due to the substantial increase in the surface-to-volume ratio. In this work, we establish a model of a cross-shaped micromixer with structural roughness elements using the finite-element software Comsol. A comprehensive study is conducted to assess the effects of roughness parameters on mixing performance. Our findings indicate that the roughness height can improve mixing quality compared to smooth channels, which is attributed to the extrusion of roughness on the working medium at a low Reynolds number (Re) of 1 and the increase of lateral velocity at high Re = 50. When the roughness height is increased from 2 to 20 μm, the maximum mixing quality is increased by about 7.4 and 32.8% at Re = 1 and 50, respectively. Furthermore, narrowing the roughness pitch enhances the perturbation frequency of microfluidics, thus facilitating the mixing process. When the pitch is reduced from 200 to 20 μm, the maximum mixing quality at Re = 1 and 50 increases by about 1.9 and 13.8%, respectively. This paper provides new insights into the influence of microrough structures on mixing.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810989","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}

引用次数: 0

Investigation of quantum tunnelling on the metallic hydride surfaces in the electrolysis process 电解过程中金属氢化物表面量子隧穿的研究

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02847-7

Mehdi Moosavi, Hossein Zaki Dizaji, Amin Seyyedi

引用次数: 0

Lax pairs, infinite conservation laws of stochastic potential Korteweg–de Vries equation and their solutions by using Darboux transformation 随机势Korteweg-de Vries方程的松弛对、无限守恒律及其用达布变换的解

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02856-6

Nanda Kanan Pal, Prasanta Chatterjee, Abdul-Majid Wazwaz, Santanu Raut

引用次数: 0

Solitary pattern solution of fractional Triki–Biswas and generalised KdV–Zakharov–Kuznetsov equations 分数阶Triki-Biswas方程和广义KdV-Zakharov-Kuznetsov方程的孤立模式解

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-12-13 DOI: 10.1007/s12043-024-02863-7

Baljinder Kour, Ashish Arora, Deep Singh

引用次数: 0

Precise solution and chaos analysis of a higher-order nonlinear Schrödinger equation in the critical point of surface gravity wave mechanics 表面重力波力学临界点高阶非线性薛定谔方程的精确求解与混沌分析

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-11-27 DOI: 10.1007/s12043-024-02853-9

Chuanqi Li

引用次数: 0

Transient features of mass diffusion of MHD slip flow over an unsteady permeable stretching sheet in the presence of a moving free stream, destructive/constructive chemical reaction and variable mass flux 在存在移动自由流、破坏性/建设性化学反应和可变质量通量的情况下，MHD 滑动流在非稳定渗透性拉伸片上的质量扩散瞬态特征

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-11-23 DOI: 10.1007/s12043-024-02851-x

Rakesh K R Saha, Hiranmoy Maiti, Swati Mukhopadhyay

{"title":"Transient features of mass diffusion of MHD slip flow over an unsteady permeable stretching sheet in the presence of a moving free stream, destructive/constructive chemical reaction and variable mass flux","authors":"Rakesh K R Saha, Hiranmoy Maiti, Swati Mukhopadhyay","doi":"10.1007/s12043-024-02851-x","DOIUrl":"10.1007/s12043-024-02851-x","url":null,"abstract":"<div>An investigation is carried out to explore the combined effects of Thompson–Troian (T–T) slip and variable mass flux on the mass diffusion of unsteady flow of viscous liquid passing a permeable stretched surface. Constructive/destructive chemical reaction has also been considered in this study. In several engineering sectors including aerodynamics, for HVAC (heating, ventilation and air conditioning) systems, it is essential to have a clear idea about the free stream velocity and how to control it. Trusting on this fact, moving free stream is considered here. This, along with the T–T slip, makes the present research distinct. With the help of ‘similarity transformations’, the governing equations along with the conditions at the boundary are transformed to self-similar forms and using fourth-order Runge–Kutta method with shooting technique by the help of bvp4c package in MATLAB software, solutions are obtained numerically. The influences of relevant parameters on the flow, solute distribution, shear stress and concentration at the surface are analysed in detail. Due to enhanced values of unsteadiness, slip and magnetic parameter, flow velocity decreases. Fluid concentration rises for rising strength of the magnetic field and slip whereas increasing unsteadiness causes the fluid concentration to decrease. Flow velocity is boosted up for rising values of velocity ratio parameter. When the slip parameter increases from 0.1 to 0.5, (36.323%) increase in velocity gradient and (8.262%) increase in surface concentration occur. When the slip parameter increases from 0.1 to 0.5, 36.323% increase in velocity gradient and 8.262% increase in surface concentration occur.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691855","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}

引用次数: 0

Pressure-induced iso-structural phase transitions in pyrochlore iridates (A_2hbox {Ir}_2hbox {O}_7) ((A! ,=,)Pr, Gd, Dy and Er) 热绿核铱酸盐（A_2/hbox {Ir}_2hbox {O}_7) ((A!,=,)Pr, Gd, Dy and Er)中压力诱导的等结构相变

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-11-23 DOI: 10.1007/s12043-024-02852-w

M Rosalin, Sebabrata Kisku, Prachi Telang, Surjeet Singh, D V S Muthu, A K Sood

{"title":"Pressure-induced iso-structural phase transitions in pyrochlore iridates (A_2hbox {Ir}_2hbox {O}_7) ((A! ,=,)Pr, Gd, Dy and Er)","authors":"M Rosalin, Sebabrata Kisku, Prachi Telang, Surjeet Singh, D V S Muthu, A K Sood","doi":"10.1007/s12043-024-02852-w","DOIUrl":"10.1007/s12043-024-02852-w","url":null,"abstract":"<div>We investigated pressure-induced changes in pyrochlore iridates ((A_2hbox {Ir}_2hbox {O}_7), (A=) Pr, Gd, Dy and Er) using Raman spectroscopy and X-ray diffraction. All four compounds exhibited a pressure-driven isostructural transition associated with the rearrangement of (hbox {IrO}_6) octahedra in the pyrochlore lattice. Interestingly, the critical pressure ((P_textrm{c})) for this transition correlates inversely with the A-site cation radius, (P_textrm{c}) decreased from (sim )10.8 GPa (Er, smallest cation) to (sim )7.5 GPa (Pr, largest cation). Additionally, the bulk modulus systematically decreases with increasing ionic radius of A-site across the (A_2hbox {Ir}_2hbox {O}_7) series. High-pressure Raman spectroscopy revealed anomalous decrease of the linewidth with increasing pressure for Ir–O ((T_{2g}^{4})) and Ir–O–Ir ((A_{1g}) and (E_g)) vibrational modes, suggesting a suppression of electron–phonon coupling due to enhanced electronic bandwidth under pressure.\u0000</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691864","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}

引用次数: 0