Pramana最新文献_第10页

Stability of dual solutions in aqueous Ti-alloy nanofluid with thermal radiation effect 具有热辐射效应的钛合金纳米流体水溶液中双重溶液的稳定性

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-27 DOI: 10.1007/s12043-024-02775-6

Har Lal Saran, C h RamReddy

{"title":"Stability of dual solutions in aqueous Ti-alloy nanofluid with thermal radiation effect","authors":"Har Lal Saran, C h RamReddy","doi":"10.1007/s12043-024-02775-6","DOIUrl":"10.1007/s12043-024-02775-6","url":null,"abstract":"<div>The current article has identified dual solutions and their stability for the Ti-alloy/water nanofluid over an exponentially shrinking sheet, while taking into consideration the presence of magnetic fields, radiation and thermal buoyancy forces. The Tiwari and Das model has been utilised to formulate mathematical equations, which have subsequently been transformed from partial differential equations to ordinary differential equations using suitable similarity transformations. The transformed equations have been solved using the shooting method incorporated with the Runge–Kutta technique. Through the application of these techniques, it has been ascertained that multiple solutions have emerged for this problem. To assess the stability of these solutions, the eigenvalue approach has been employed. The eigenvalue approach has revealed that only the first solution is physically viable in laboratory settings, while the second solution is not. The effects of radiation on temperature, skin friction, velocity and heat transfer rate have been elaborated upon in detail. Furthermore, flow separation points have been identified and the rationale behind the delay in flow separation has been expounded upon. Streamlined patterns have been drawn and explained to enhance our understanding of the fluid flow behaviour. Finally, it is worth noting that these types of studies have significant applications in the medical and aerospace industries.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529814","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

Dissipative heat effects on the Jeffrey nanofluid flow through horizontal channels during a binary chemical reaction dynamics 二元化学反应动力学过程中杰弗里纳米流体流经水平通道时的耗散热效应

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-27 DOI: 10.1007/s12043-024-02785-4

S Acharya, Meenakshi Panda, B Nayak, S R Mishra

引用次数: 0

The classification of exact travelling wave solutions to two-component Dullin–Gottwald–Holm system 双分量杜林-戈特沃尔德-霍尔姆系统精确行波解的分类

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-27 DOI: 10.1007/s12043-024-02787-2

Lintao Guo, Hua Xin

引用次数: 0

Influence of copper doping on structural, morphological and optical properties of tin oxide (Sn1−xCuxO2−δ) 铜掺杂对氧化锡（Sn1-xCuxO2-δ）结构、形态和光学特性的影响

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-27 DOI: 10.1007/s12043-024-02778-3

Archana Verma, B Das

{"title":"Influence of copper doping on structural, morphological and optical properties of tin oxide (Sn1−xCuxO2−δ)","authors":"Archana Verma, B Das","doi":"10.1007/s12043-024-02778-3","DOIUrl":"10.1007/s12043-024-02778-3","url":null,"abstract":"<div>The primary goal of this paper is to study a few advantages of bulk nanoparticles of Cu-doped SnO2 using the solid-state reaction method. Many innovative methods were employed to evaluate the special tuning of the bandgap and other structural and morphological properties of the material. X-ray diffractometer (XRD) confirmed that tin oxide has a rutile-type tetragonal-shaped structure with space group P42(/)mnm. The average crystallite size was calculated which was found to increase from 53 to 80 nm by increasing the Cu-doping from x (=) 0 to x (=) 0.30. SEM images specified that nanoparticles are inhomogeneous and densely close to each other and the average particle size was found to be in the range of ~225–430 nm. Transmission electron microscopy (TEM) images showed the grains present in a few cubic and spherical shapes and grain size was increased (~20–90 nm) with doping of copper in the SnO2 lattice. UV–Vis spectroscopy showed that the band gap increased from 3.531 to 3.701 eV for pure SnO2 and Cu-doped SnO2, respectively. XPS identified the electronic state of Sn as well as Cu atoms as (4^{+}) and (2^{+}), respectively. Raman spectroscopy showed that only three vibrational modes, i.e., A1g, B2g and doubly degenerate Eg, exist in a sample.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141522205","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

Doping properties in Co(_{3-x})Ni(_{x})O(_{4}), comparison between p-DFT and experimental values Co$_{3-x}$Ni$_{x}$O$$_{4}$$ 中的掺杂特性，p-DFT 值与实验值的比较

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-13 DOI: 10.1007/s12043-024-02772-9

C A Aguirre, P DÍaz, D. Laroze, M R Joya, J Barba-Ortega, A S Mosquera Polo

{"title":"Doping properties in Co(_{3-x})Ni(_{x})O(_{4}), comparison between p-DFT and experimental values","authors":"C A Aguirre, P DÍaz, D. Laroze, M R Joya, J Barba-Ortega, A S Mosquera Polo","doi":"10.1007/s12043-024-02772-9","DOIUrl":"10.1007/s12043-024-02772-9","url":null,"abstract":"<div>In the present work, we numerically and experimentally study the Co(_{3-x})Ni(_{x})O(_{4}) (spinel-like oxides) system. Using the perturbative density functional theory (p-DFT) method, we start the study from the homogeneous sample ((x=0)), obtaining the main electronic properties (band structure (BS), density of states (DOS), and Fermi surface (FS)). Subsequently, we doped (x) with Ni atoms in different proportions (0–7% respectively, taking 56 atoms as 100% and the percentage of doping, on this percentage). As we increase the doping ((xne 0)), we have found that the forbidden gap decreases and the Fermi energy (FE) decreases, causing the material to exhibit a transition phase for a particular doping value. In addition, we find that more bands are generated when the system is doped, which would be responsible for the phase transition. The data from the theoretical analysis carried out in this paper was compared with the experimental data of various widely accepted works. Some of the results, when compared with the information available from the experimental ones, show good agreement.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141346292","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

Thermodynamics of one- and two-qubit quantum refrigerators interacting with squeezed baths: a comparative study 与挤压浴相互作用的一比特和二比特量子制冷器的热力学：比较研究

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-07 DOI: 10.1007/s12043-024-02776-5

Ashutosh Kumar, Sourabh Lahiri

引用次数: 0

Structural, electronic and magnetic properties of pure and Fe-doped ZnSe: first-principles investigation 纯 ZnSe 和掺 Fe ZnSe 的结构、电子和磁特性：第一原理研究

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-07 DOI: 10.1007/s12043-024-02752-z

Vusala Nabi Jafarova

引用次数: 0

Diverse exact and solitary wave solutions to new extended KdV6 equation using IM extended tanh-function technique 利用 IM 扩展 tanh 函数技术求解新扩展 KdV6 方程的多种精确解和孤波解

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-07 DOI: 10.1007/s12043-024-02767-6

Wafaa B Rabie, Hamdy M Ahmed

引用次数: 0

Exact solutions to the forced KdV equation via three efficient techniques 通过三种高效技术精确求解受迫 KdV 方程

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-06-07 DOI: 10.1007/s12043-024-02774-7

Sanjaya K Mohanty, Md Sagib, Mohasena Ahmed

{"title":"Exact solutions to the forced KdV equation via three efficient techniques","authors":"Sanjaya K Mohanty, Md Sagib, Mohasena Ahmed","doi":"10.1007/s12043-024-02774-7","DOIUrl":"10.1007/s12043-024-02774-7","url":null,"abstract":"<div>In this work, the exact travelling wave solutions to the forced Korteweg–de Vries (fKdV) equation with different force terms are studied with the help of symbolic computations. This equation is derived from a straightforward mathematical model that describes the behaviour of a shallow fluid layer when influenced by external forces. The fKdV equation has many applications in diverse fields, including fluid dynamics, plasma physics, soliton theory and mathematical physics, for modeling wave propagation and nonlinear phenomena under the influence of external forces. Solitary wave solutions for this equation have been derived using three distinct techniques: the extended ((G^prime / G))-expansion method, the Kudryashov method and the ((1/G^prime ))-expansion method. As a result, several new solutions have been achieved which are in the form of hyperbolic, trigonometric, rational and exponential functions. Finally, the effects of different time-dependent external forces have been studied by presenting 3D, 2D and contour plots. It can be seen that the external forces affect the background and speed of solitary waves. The results could be expected to be helpful in understanding the propagation of solitary waves subjected to external forces.</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 3","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141372282","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

Growth, structural, thermal and THz generation properties of modified DAST, CMST and BMST crystals: A comparative study 改性 DAST、CMST 和 BMST 晶体的生长、结构、热和太赫兹生成特性：比较研究

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2024-05-28 DOI: 10.1007/s12043-024-02753-y

S Shanmuga Sundari, D Ganesh, P Kanchana, N Arnadevi, A K Chaudhary, B Prabha Devi

{"title":"Growth, structural, thermal and THz generation properties of modified DAST, CMST and BMST crystals: A comparative study","authors":"S Shanmuga Sundari, D Ganesh, P Kanchana, N Arnadevi, A K Chaudhary, B Prabha Devi","doi":"10.1007/s12043-024-02753-y","DOIUrl":"10.1007/s12043-024-02753-y","url":null,"abstract":"<div>Growth of 4-N-N-dimethylamino-4(^prime )-N(^prime )-methyl-stilbazolium tosylate (DAST), 4-chloro-N-methyl 4-stilbazolium tosylate (CMST) and 4-bromo-N-methyl 4-stilbazolium tosylate (BMST) crystals by slope nucleation technique using mixed solvents are reported. Investigation on compositional, structural, thermal, luminescent and dielectric properties of these crystals were studied. Purity and the crystal quality are analysed using NMR and XRD. The thermal stability of the crystals is studied in detail from the TG-DTA. Emission characteristics are examined by photoluminescence spectra. Finally, 800 nm wavelength of 140 and 50 fs duration of pulses obtained from Ti:sapphire oscillator and amplifier were used for the measurement of refractive indices and absorption coefficients and generation of terahertz (THz) radiation. The conversion efficiency of DAST, CMST and BMST with respect to incident laser power of 150 mW were of the order of (0.67 times 10^{-4}), (0.826times 10^{-4}) and (0.947 times 10^{-4}), respectively. Finally, the significance of effective polarisability in THz generation has been demonstrated in terms of rotational angle (theta ).</div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141167591","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