Modern Physics Letters B

In this study, the hub cutting of the impeller was presented to suppress the rotor–stator interference between the blade and volute tongue in a high-speed centrifugal pump with double volutes. The flow fields in the centrifugal pumps with four hub-cutting angles 0, 15^∘, 30^∘ and 45^∘ were numerically simulated to investigate the influence on the internal flow and pressure pulsation using SST $k-\omega$ turbulent model. The predicted results of numerical simulation were in good agreement with the experimental ones. The results show that the relative velocity streamline distribution is more uniform and smoother in hub-cutting impeller compared with that in the original one. Also, the head and efficiency of the pumps with hub-cutting impeller are higher than that of the prototype pump, with the maximum increase of 1.97% of the head for the hub-cutting angle 45^∘ under the design flow rate. The pressure pulsation intensity at volute 1 and the unsteady radial force of the hub-cutting pumps are smaller than that of the prototype pump due to the flow improvement. In addition, the maximum and average values of the unsteady radial force decrease with the increase of the cutting angle.

The viscoelastic effects on the double diffusive oscillatory flow in a fluid-saturated porous layer are investigated. A modified Darcy–Oldroyd-B model is used to characterize the non-Newtonian fluid behavior flow in a porous layer. Analytic solutions of the dimensionless governing equations of fluid flow are obtained and the effects of the flow parameters on temperature, concentration, velocity profiles, skin friction and rate of heat transfer are discussed and shown graphically. It is interesting to note that skin friction increases on both channel plates as injection increases on the heated plate. Increase in the strain retardation parameter is to decrease the fluid velocity, while an opposite trend is noticed with increasing stress relaxation parameter. The study reiterates that the consideration of viscoelastic fluid is very important in proper considerate of oscillatory flow in double diffusive fluid systems.

In developing current flow phenomena, the proposed study is carried out by the consideration of ternary hybrid nanofluid flow past a stretching surface. The flow became electrically conducting due to the inclusion of transverse magnetic field along the normal direction of the flow. Further, the energy profile is enhanced for the interaction of the radiative heat using Rosseland approximation. The innovation behind this approach is due to the assumption of the various shapes of the particles, i.e. spherical, cylindrical along with platelet-shaped nanoparticles and the corresponding physical properties are demonstrated. In view of physical phenomena, carbon nanotube, graphene, and aluminum oxide nanoparticles with water as a base liquid are used to prepare the hybrid nanofluid. Because of the complexity of the formulated model, the governing non-dimensional set of equations is handled by using traditional numerical technique following shooting-based “Runge–Kutta fourth-order” technique. Further, the significant role of the pertinent factors involved in the flow phenomena is the case of ternary nanofluid overshoots the fluid velocity in comparison to the case of nanofluid and hybrid nanofluid and the shear rate enhances for the increasing magnetization whereas the heat transfer rate attenuates significantly.

In this research paper, we numerically analyze the flow and heat transfer rate of non-Newtonian pseudo-plastic nanofluid with variable apparent viscosity and thermal conductivity effects, respectively, through annular sector duct. Concentric pipes annular sector duct of an apex angle, $2\beta$ and ratio of radii, $\widehat{R}$, is filled with saturated porous media. For this purpose, we utilize the power law Darcy–Brinkman flow model along with Forchheimer term. Also, the contribution of nanoparticles is accounted in carboxy methyl cellulose (CMC)-water, which has been taken as base fluid. Finite volume method (FVM) is utilized to discretize the governing mathematical model, whereas algebraic equations are solved numerically by using strongly implicit procedure (SIP). With the help of graphs, the impacts of nanoparticles’ contribution and porosity factor have been discussed by giving physical interpretation. Results are also found in the limiting sense and show the good agreement with already published data. At $\beta =\pi /3$, $\varphi =0.10$, $Da=0.01$ and $\widehat{R}=0.25$, we can observe down in $f\mathrm{\text{Re}}$ and Nu upto $5.658\%$ and $10.01\%$, respectively, when n decreases from 1 to $0.91$, whereas $13.47\%$ and $23.57\%$, respectively, by decreasing the value of n from 1 to $0.76$. For both cases of nanoparticles’ contribution, the downs in Nu have been observed same by decreasing the value of n.

Strain engineering is generally employed as an efficient means of tuning the physical properties of a target compound. In this research paper, we investigated the effect of three axial stretches on the structural, electronic, optical, and thermoelectric properties of inorganic Ge-based halide perovskites LiGeBr₃. Computations were carried out using Density Functional Theory (DFT) and the semi-classical Boltzmann transport theories. The electronic investigation indicated that LiGeBr₃ perovskite exhibits a direct bandgap of 0.480eV. The findings suggest that the bandgap is highly responsive to strain, which improves the absorption ability in the visible light range (300–500nm). The relative stability of the strained compounds and the feasibility of their synthesis were robustly demonstrated by the negative formation energies. The transport features were assessed as a function of temperature and yielded interesting results. The electrical conductivity was considerably enhanced under strain, and the highest figure of merit was found at low temperatures (approximately 0.741). Our theoretical discovery proved that strain is an enormously exciting technique for extending semiconductor applications and boosting thermoelectric and solar cell devices.

This paper investigates the numerical analysis of a highly performed surface plasmon resonance (SPRE)-based sensor employing a hybrid structure of SrTiO₃ (STO) and graphene for rapid detection of malaria. The investigation is performed using the angular interrogation technique and transfer matrix method. The SPRE device has a glass prism, silver (Ag), STO, graphene, affinity layer and sensing medium (SGM). Four coupling prisms are examined and we found the prism N-FK51A corresponds to the highest sensitivity. The sensitivity of the structure N-FK51A/Ag/STO/graphene/affinity layer/SGM is found to be 205.405, 222.222 and $258.333^{\circ }$/RIU for Schizont, Trophozoite and Ring malaria stages. The layer thicknesses are then optimized and it is found that the proposed SPRE sensor can achieve a sensitivity of 278.378, 227.027 and $400^{\circ }$/RIU for Schizont, Trophozoite and Ring malaria stages with 30 nm (silver), 1nm (STO), mono-sheet of graphene and 5nm of the affinity layer. These findings demonstrate that the proposed method and structure can be used efficiently for biomedical applications.

Recently, Ahn et al. created dumbbell-shaped silica nanoparticles, then optically levitated in vacuum, capable of spinning at 300 billion revolutions per minute, driven only by the force and torque of laser. This is by far the fastest spinning object in the world. We show that in this system, there is an additional change in momentum (or extra force) that is proportional to the change in the angular momentum of the particle (or torque). We suggest that this effect also applies to microscopic particles. In the experiment of Ahn et al., although the angular momentum of the particle itself L is large, the rate of change of the angular momentum $\dot{\mathit{L}}$ may not be large. Therefore, experimentally, the physical effects associated with changes in angular momentum can be verified either by applying very strong force and torque to the particle, or by allowing the axis of rotation of the particle to find a way to change very quickly.

This study focuses on the investigation of HIT solar cell using nanocrystalline hydrogenated cubic silicon carbide (nc-3C-SiC:H) as a window layer. The selection of nc-3C-SiC:H is motivated by its wide bandgap, high electron drift velocity, and exceptional optical, electrical, and structural properties. Employing SCAPS-1D simulator, a comprehensive simulation analysis of thin nc-3C-SiC:H-based solar cell was conducted. By analyzing the current–voltage and quantum efficiency curves, the impact of doping concentration in the window layer was examined, covering a range from $1\times 10^{15}{\mathrm{\text{cm}}}^{-3}$ to $1\times 10^{18}{\mathrm{\text{cm}}}^{-3}$. A rapid degradation of $V_{\text{oc}}$ was observed for high doping concentrations. Additionally, the temperature dependence of external DC parameters for the temperatures 273, 300, and 318K was explored under AM1.5G and AM1.5D sunlight spectra. The application of two distinct light spectra resulted in the DC parameters exhibiting minimal variation or similarity. The study also took into account the influence of window thickness variation, temperature, and doping concentration. The findings demonstrate a remarkable influence of temperature and doping concentration on the DC parameters. $J_{\text{sc}}$ value of 30.29mA/cm² was achieved with a 3-nm thickness and an optimal efficiency of 19.48% was registered with a doping concentration of up to $8\times 10^{17}{\mathrm{\text{cm}}}^{-3}$, showcasing the promising potential of nc-3C-SiC:H.

Graphene has excellent mechanical properties and vibration frequency is an important mechanical property. In this paper, the effects of doping elements and doping concentrations on the vibration characteristics of graphene nanoribbons were investigated by molecular dynamics simulation. The vibration characteristics are influenced by the doping element, depending on the bond structural difference in bond structure between doping atoms and carbon atoms. The vibration frequencies of Nitrogen (N)-doped and Nitrogen–Nitrogen (N–N)-doped graphene nanoribbons are slightly lower than those of pure graphene nanoribbons. However, the vibration frequencies of Sulfur (S)/Phosphorus (P)-doped and Sulfur–Sulfur (S–S)/Phosphorus–Phosphorus (P–P)-doped graphene nanoribbons are significantly lower than those of pure graphene nanoribbons. In addition, with the increase of S (P) doping concentration, the vibration frequency of monolayer graphene nanoribbons decreases gradually.

This study presents a comprehensive investigation into the soliton solutions for the Khokhlov–Zabolotskaya–Kuznetsov (${𝒦}{𝒵}{𝒦}$) problem using the Bernoulli sub-equation function approach, generalized Kudryashov method, and Homotopy perturbation method. The ${𝒦}{𝒵}{𝒦}$ equation, a nonlinear wave equation that governs the propagation of high-amplitude ultrasonic waves through nonlinear media, is studied in detail. Perturbation theory and asymptotic expansions are employed to derive approximate solutions for the ${𝒦}{𝒵}{𝒦}$ problem. These methodologies offer valuable insights into the behavior of ultrasonic waves in different media, thereby facilitating the optimization of ultrasonic transducer design and enhancing the precision of ultrasonic imaging systems. The analytical and semi-analytical methods utilized for solving the ${𝒦}{𝒵}{𝒦}$ equation are computationally efficient and serve as valuable resources for researchers and engineers working in the field of ultrasonics. The outcomes of this study carry significant implications for the understanding of ultrasonic wave behavior in nonlinear and dissipative media, ultimately contributing to the development of more accurate and efficient ultrasonic imaging techniques.

Within the framework of the extended Hubbard model on a hexagonal lattice, the effect of sublattice symmetry breaking on the position of the semimetal-antiferromagnet phase transition is studied. The study is carried out using the Quantum Monte Carlo method with five auxiliary Hubbard fields. It is shown that the difference in the intensity of the on-site interaction of electrons on the sublattices leads to a shift of the phase transition point towards lower values of the interaction parameter. An antiferromagnetic condensate is considered.

The structural, electronic, optical, mechanical and vibrational properties of hexagonal Di-Tellurium-Tungsten (Te₂W) are exploited with a hybrid Heyd–Scuseria–Ernzerhof 2003 (HSE03) functional and semi-local general gradient approximation (GGA) scheme using ab initio density functional theory (DFT) calculations. The structural and electronic properties have been analyzed with the band structure and electron orbitals from the partial density of states (PDOS). Our reflectivity data from optical spectra explain its applications over mechanical engineering such as lubricant oils, further with the fact that the refractive index results obtained suggest the possibility of deploying Te₂W material over optical displays. Our work finalizes by testifying the physical and mechanical stability, with our DFT-calculated elastic coefficients along with its criteria, mechanical moduli and phonon data provided. In general, our non-local hybrid functional corrects the band structure and bandgap energy $E_g$ extremely well, over the traditional semi-local exchange-correlation functional.