Modern Physics Letters B

This analysis is framed to take care of the high heat transfer demand from various application prospects and in this context nanofluid may be in consideration because nanofluids are well-known liquids with higher heat transfer capabilities. Here, a mixed convection flow of Molybdenum disulfide-water (MoS₂-H₂O) nanofluid on a moving vertical plate is examined when there are chemical reactions. Nanofluid problem is investigated using Tiwari and Das model, and numerically solved by “bvp4c” method. For the considered effects in the study, overshoots in temperature profile of nanofluid are observed. Momentum and thermal layer thicknesses become thinner with suction and thicker with blowing. Temperature overshoot is higher for blowing cases. Enhanced homogeneous–heterogeneous reactions lead to rise of the concentration boundary layer’s thickness. Also, magnitude of surface-drag force decays and cooling rate enhances with MoS₂-H₂O nanofluid mixed convection. For weaker suction and for blowing, cooling of nanofluid is faster with larger volume fraction of nanoparticles, but contrast results are obtained for greater suction. Importantly, compared to the homogeneous reaction, the heterogeneous reaction exhibits more impactful influences on flow and heat-mass transport characters.

More and more studies indicate that the effects of quantum size and energy level statistics play a crucial role in the thermodynamic properties of ultrasmall metallic grains. This paper aims to investigate how they affect the specific heat of ultrasmall metallic grains in magnetic field. As the particle size decreases, fluctuation effects and the impact of energy level separation are becoming more and more important. The method of static path approximation (SPA) is adopted to handle the fluctuation effect. Random matrix theory (RMT) is adopted due to its successful description of the energy level of metal nanoparticles. The normalized specific heat of several typical temperatures and electron spins were taken in the calculation, and the results were analyzed. It was found that spin and the spin-orbit coupling affect the specific heat very obviously, and the suppressed high spin weakens the contribution of electrons to the heat capacity.

There is still no consensus about the relaxation behavior of the so-called 50K-relaxation in acceptor and donor co-doped TiO₂ system. Herein, the relaxation behavior of the 50K-relaxation was investigated in (Tm$+$Ta) co-doped rutile TiO₂ ceramics. Dielectric properties of the sample were studied in the temperature range of 2–300K under 100 frequencies in the range of 10²–10⁶Hz. The sample shows a pronounced 50K-relaxation. Various relaxation behaviors of Arrhenius, Mott’s variable range hopping, and Vogel Fulcher laws were tried to describe the relaxation. The result indisputably evidences that the 50K-relaxation follows the Vogel Fulcher law. This work provides a heuristic hint to understand the fundamental physics underlying the colossal permittivity behavior in the acceptor and donor co-doped TiO₂ ceramics system.

In this work, the electronic structure and optical properties of Zr-doped $\beta$-Ga₂O₃ with interstitial H and O vacancies were studied by using first-principles generalized gradient approximation combined with the Hubbard U method based on density functional theory. The energy band structure, density of states, absorption spectrum, effective mass, mobility and conductivity of the doped system were calculated and analyzed. Results showed that the doped system was more stable under the Ga-rich condition than under the O-rich condition. With the increase in Zr doping concentration, the bandgap of the $\beta$-Ga₂O₃ system gradually narrowed and the absorption spectrum of the system blue-shifted in the wavelength range of 162–275nm. System conductivity was enhanced by Zr doping, decreased by O vacancies and greatly improved by interstitial H. Therefore, doping Zr into the $\beta$-Ga₂O₃ system is important for improving material properties and preparing electronic and optical devices.

Non-Newtonian materials have been an appealing topic for researchers because of the variety of laboratory and industrial process involving these fluids. There are several kinds of non-Newtonian fluids classified according to their properties. In this study, the Maxwell fluid model is analyzed due to the unique properties and applications of this non-Newtonian material. We have considered the Buongiorno model for nanofluid, which is a two-phase model that accounts for the effects of Brownian motion and thermophoresis on the transport of nanoparticles in a fluid. A stretching surface holding a chemically reactive fluid is assumed. In addition, the study also considers the impacts of heat flux and magnetic fields. The influence of various physical factors on the flow fields is presented and graphically highlighted. Using linear regression and the data point approach, the relationship between the physical parameters, such as rate of heat and mass transfer, at the surface is investigated. The relationship between the various physical parameters was investigated using the t-test approach. The Maxwell fluid parameter influences heat transmission at the surface. As the magnetic field and heat source parameters increases, the rate of heat transfer decreases. Increasing the Deborah number, chemical reaction parameter and magnetic field parameter enhances the mass transfer rate at the surface. The fluid’s velocity decreases with rising magnetic field and Maxwell fluid parameters. The heat source parameter elevates fluid temperature, while inclusion of the chemical reactions parameter reduces nanoparticle concentration.

This work deals with the simulation of a perovskite solar cell with structure, ITO/SnO₂/MAPbI${}_{3-x}$Cl_x/Spiro-MeOTAD/Ag using SCAPS-1D software. The optimization of absorber thickness and carriers’ lifetime results in $\mathrm{\text{PCE}}=19.70$% ($V_{\text{oc}}=1.14$V, $J_{\text{sc}}=24.31$mA/cm² and $\mathrm{\text{FF}}=70.88$%). The same structures are also analyzed without ETL and HTL for making cost-effective solar cell. The efficiencies for both ETL and HTL free structures are found to be 17.42% and 9.98%, respectively. Further, the optimization of gradient doping shows a significant increment in performance parameters i.e. $\mathrm{\text{PCE}}=24.42$% ($V_{\text{oc}}=1.19$V, $J_{\text{sc}}=23.98$mA/cm² and $\mathrm{\text{FF}}=84.84$%). Moreover, the analysis of various factors like average doping concentration, number of absorber sublayers, recombination velocities and temperature on the cell performance are performed to examine device stability. Present observations suggest that by considering only two sublayers, one can achieve the highest cell performance by using the gradient doping method. We have also validated the cell performance by comparing it with the experimental results and found a good agreement in both. Our findings may provide an effective route to fabricate highly efficient solar cell devices.

This paper conducts an extensive comparative analysis of numerical methods employed in modeling blood flow through arteries with Magnetohydrodynamics (MHD) and hybrid nanofluids. The study investigates the effectiveness and precision of distinct numerical approaches: Akbari Ganji’s Method (AGM), Fourth-Order Runge–Kutta (RK4), Finite Volume Method (FVM), and the Finite Element Method (FEM). These methods are essential for comprehending the intricate fluid dynamics that arise in the presence of magnetic fields and hybrid nanofluids a phenomenon relevant in numerous medical applications. Blood flow is subjected to a homogeneous magnetic field in a radial direction while the magneto-hemodynamics effect is taken into account. A variety of medical, physiological, and surgical procedures, as well as the regulation of blood pressure, heat distribution, wound healing, diagnostic imaging, and drug discovery, depend on blood flow through arteries to carry out vital functions such as oxygen and nutrition delivery, organ maintenance, and wound healing. Our findings highlight that while each method has strengths, their applicability varies based on the problem’s characteristics and computational resource constraints. This analysis aids researchers and practitioners in selecting the most suitable method for their modeling requirements, advancing numerical techniques for complex fluid dynamics involving MHD and hybrid nanofluids.

In this paper, we delve into a nuanced aspect of the distillability problem within the realm of entanglement theory, specifically examining the distillability of anti-diagonal $4\times 4$ entangled Werner states under the framework of local operations and classical communication (LOCC). To address this, we scrutinize a conjecture central to the distillability issue, initially focusing on its implications in 4-dimensional and 5-dimensional contexts. Through rigorous calculations, we establish that these cases align with the conjecture. Subsequently, we broaden our investigation to encompass $n\times n$ matrices, demonstrating that both even and odd n-dimensional anti-diagonal matrices are in concordance with the conjecture, thus contributing to a deeper understanding of the distillability problem in quantum entanglement.

In this work, we investigated the magnetic annihilation and reconnection and the resulted hot electron acceleration driven by double-beam intense laser pulses in two-layer near critical density (NCD) plasma target. The results are obtained by performing two-dimensional (2D) particle-in-cell (PIC) simulations. It is found that a quasi-mono-energetic peak can be formed in the energy spectrum of electrons accelerated by the process of magnetic field annihilation (MA) at cutoff energy. Electron spectra feature depends on the length of the second low-density layer. This suggests that the process of relativistic magnetic annihilation may be controlled in experiments by target design.

In this paper, we take variable separation method to study Klein–Kramers (KK) equation. By choosing different eigenvalues and noise functions, we can get different probability density functions (PDFs) of KK equation. These PDFs contain not only normal distributions but also other distributions that correspond to anomalous diffusion phenomena. For example, power-law distribution, truncated Cauchy–Lorentz distribution, Weibull distribution, log-logistic distribution, Gamma distribution. We also show the 3D and 2D profiles of these PDFs to analyze the corresponding dynamic properties and illustrate the possible practical applications of these results. In addition, we also find some exact solutions that are not PDFs. They are also listed to ensure the completeness of the results and to illustrate the potential applications of these exact solutions.

The primary purpose of this study is to provide more information on the stable and incompressible stream of a hybrid nanofluid over a poignant tiny needle in two dimensions under slip boundary conditions. In the hybrid nanofluid flow, Al₂O₃ and Fe₃O₄ are nanoparticles, water and ethylene glycol (50:50) are considered as the base fluids. Furthermore, the impacts of Joule heating and inclined magnetic fields are considered. The PDE’s governing equations are converted into ODEs by using similarity transformations and solved by a numerical technique based on Runge–Kutta fourth-order method. The results illustrate that the crucial parameters such as the magnetic parameter, Eckert number, nanoparticles of solid volume fractions, inclined angle parameter, and Prandtl numbers significantly affect the momentum and thermal profiles. The heat transfer rate and skin friction factors are used to calculate the numerical values of various parameters, which are displayed in a table. These analyses manifest that raising the magnetic parameter results in a decrease in the hybrid nanofluid velocity under slip and no-slip circumstances. The Nusselt number has also grown as a result of the volumetric fractions of nanoparticles and the intensification of the angle parameter. This analysis might include areas such as microfluidics, biomedical devices, heat exchangers, and other engineering applications where precise control over fluid behavior and temperature distribution is important.

Using density functional theory and Boltzmann equations, this study calculates and compares the electronic, optical, thermoelectric, and thermodynamic properties of bulk and single-layer germanium carbide structures. It has been shown that germanium carbide in the bulk structure has an indirect energy band gap of 1.61eV. In a single layer structure, it is a metal. Thermodynamic properties including specific heat at constant volume have been investigated using the quasi-harmonic approximation (QHA) package in QE. According to the studies conducted on optical properties, this material shows good reflection in the visible region. In addition, this structure has high electrical conductivity and low thermal conductivity, which is essential for thermoelectric materials. Thermoelectric calculations using semi-classical Boltzmann transfer theory show that the performance of two-dimensional compounds with graphene gives good thermoelectric results. At 100K, the highest figure of merit (ZT) for GeC is 1.00. Our findings evaluate the GeC compound as a suitable thermoelectric material in the temperature gradient from 100 to 900K.

This study examines Titania nanofluids that conduct electricity and are combined with various base fluids, focusing on various aspects. A magnetic field analyzes a continuous flow of nanofluid over a rotating disk that is positioned at an angle with a three-dimensional geometry assumption. The continuity, momentum, and energy balance equations are established, transformed using similarity variables, and solved through Akbari–Ganji Method (AGM) and Homotopy Perturbation Method (HPM) semi-analytical methods. The effects of several parameters, such as Magnetic parameter (M), Hall parameter (m), Porosity parameter ($\gamma$), Radiation parameter (Rd), and Thickness of liquid ($\delta$), are examined through a graphical representation of state variables, including skin friction and Nusselt number. Additionally, the Response Surface Method (RSM) method has been utilized to simultaneously display the effects of porosity parameters and various factors across the disk. The findings showed that the magnetic, porosity, Hall, and thickness parameters had a significant impact on the behavior of the nanofluid. Specifically, the magnetic field had a strong influence on the velocity and temperature distribution of the fluid as it flowed over the rotating disk, while changes in porosity, Hall, and thickness parameters also affected these state variables.

In order to solve the security of electronic transactions on limited goods, some quantum blind double signature (QBDS) protocols were proposed. In existing QBDS protocols, all participants must have specific quantum computing capabilities. Realistically, high cost of quantum devices may hinder people from using the QBDS protocol. Therefore, we propose a semi-quantum arbitrator blind double signature (SQABDS) scheme. In this scheme, the sender (signer) and the receiver both are classical participants, which can relatively reduce the dependence on quantum hardware. The introduction of blind signers can protect the privacy of electronic transactions, the introduction of semi-trusted arbitrator can relax the strong assumption about the trustworthiness of the arbitrator, for the arbitrator cannot forge the signature. In addition, the SQABDS scheme can be used to sign classical messages directly without performing any quantum swapping tests or quantum gate operations. Finally, the analysis shows that our scheme is securer and its quantum cost is relatively lower.

The nanoporous materials derived from the ZiF-8 metalorganic framework are highly interesting because of their features like good thermal stability, catalytic performance, and electric conductivity. Therefore, ZiF-derived metal oxide was utilized in several applications, for instance, energy storage and environmental remediations. Herin, we compare the as-prepared ZnO, ZiF-8, and ZnO derived from ZiF-8 in terms of structural, thermal, and morphological properties. Thus, the photocatalytic performance of all compositions. The preparation process is an effective parameter in the morphology of the sample surface. The as-synthesized ZnO had nanoparticle morphology with a size of 50–80nm. However, the ZiF-8 has cubic morphology with a long rod. The decomposition of ZiF-8 converted the sample to ZnO coated by carbon, indicating a high surface and fit morphology for photocatalysis. These results mean that ZnO derivative from ZiF-8 nanoparticles has the best efficiency for water desalination with 95%. ZnO drives from ZiF-8 demonstrated the smallest charge transfer resistance compared to that of as-prepared ZnO, and ZIF-8, coinciding with the conclusion of the EIS results. The transient photoresponses and electrochemical impedance spectra of the compounds were used further to explore the separation efficiency of the photogenerated charge carriers.