Modern Physics Letters B

The consequence of thermal radiation vis-a-vis external heat generation/absorption on the inertial drag force of a hybrid nanoliquid flow in three-dimensional geometry is investigated. It is proposed that with the symmetric or non-symmetric particle shape, the velocity differs because of the direction of the drag. Furthermore, the conducting fluid for the interaction of the magnetic field through a permeable medium past an expanding surface influences the flow phenomenon. The present analysis is useful for the dialysis of blood in the artificial kidneys, the flow of blood in capillaries as well as the design of filters in engineering problems. However, the formulated problem is transformed into its non-dimensional form for the implementation of particular similarity rules. The set of nonlinear governing equations with specific contributing parameter values is subjected to handle by employing shooting-based Runge–Kutta fourth-order technique. Because of the system’s irreversibility, the simulation of entropy and the Bejan value is the main draw. For each profile, the graphical results of specific parameters such as momentum, temperature, entropy, and the Bejan number are shown. Further, the important outcomes are the axial and the transverse velocity profiles are restricted by the inclusion of volume concentration in association with magnetic field and the enhanced Brinkman number augments the entropy generation significantly. However, the numerical validation shows a good correlation between the earlier investigations in particular cases.

In this study, the coupling and the relative sensitivity characteristics of a Dual-Core photonic crystal fiber (DC-PCF)-based liquid sensor are evaluated by employing the full-vectorial finite element method (FV-FEM). The simulation results demonstrate that coupling length of the proposed sensor varies between 2mm and 0.2mm length at wide wavelength range (800–1600nm) for low index analytes (1.33–1.36). Besides, birefringence of order $\approx 10^{-4}$ is reported. It is found that analyte with 1.36 index reaches higher sensitivity levels. On the other hand, the coupling length of the proposed sensor can be optimized with the ellipticity ratio of the central core hole. Bending analysis on coupling length and optical power fluctuations is also reported. It is found that the power flow in one core is increasing almost 90% towards the bending direction. The proposed structure with simple design parameters has a great potential in various biomedical applications including DNA detection and can also be employed as fiber-based refractometer in various sensing applications.

In this paper, we proposed a new model based on the electron tunneling effect in a four-level quantum dot molecule (QDM) for studying the optical bistability (OB) and optical multistability (OM). The QDM interacts with a probe and two coupling and Laguerre–Gaussian (LG) fields. We found that by adjusting the electron tunneling effect and the parametric controlling of LG light, the transition from OB to OM or vice versa is possible. Moreover, due to the simultaneous interaction between coupling and LG lights with the same optical transition adjusting the threshold of OB and OM by orbital angular momentum (OAM) of the LG light becomes achievable. Our results show that by adjusting the simultaneous effect of electron tunneling and OAM state of the vortex light, the favorable OB and OM patterns with adjustable intensity thresholds are achievable. Our proposed model may have potential application in quantum information science based on quantum dot (QD) devices.

In this paper, we analyze quantum walks on cycles with an absorbing wall. We set the absorbing wall on cycles with N vertices (where N is an even number), and divide $|\phi (t)〉$ into two parts, $L(t)$ and $R(t)$. Due to the periodicity of the cycles, the condition $L(M+N)=L(M)$ (or $R(M+N)=R(M)$) is applied to $L(t)$ and $R(t)$, then the transmission probability $P_M$ and reflection probability $Q_M$ at the absorbing wall $n=M(M=\frac{N}{2})$ at time t are obtained. Furthermore, we show that over time, the absorbing wall absorbs less and less.

The structural, mechanical, and electronic properties of rubidium iodide (RbI) have been extensively investigated utilizing the generalized gradient approximation (GGA) and the full-potential linearized augmented plane wave (FP-LAPW) approach. The potential was roughly calculated using a modified Becke–Johnson (mBJ) approximation, which increased the precision of the electronic properties. In this study, RbI is analyzed in a wide range of crystal structures, including topologies like rock salt (RS), CsCl, zinc blende (ZB), NiAs, and wurtzite (WZ), among others. Our research shows a strong relationship between the material’s physical properties and the conclusions drawn from both theoretical and experimental studies. Significantly, our results show that the RS form corresponds to RbI’s ground state. All the aforementioned topologies display wide-bandgap semiconductor capabilities, according to further examination of their electronic band structures. Notwithstanding these findings, it was discovered that RbI has a poor fracture resistance due to its low bulk modulus. Born’s stability analysis has shown that RbI is stable in the RS, CsCl, ZB, NiAs, and WZ structures. All RbI structures were discovered to have ionic bonding and to be ductile, and every stabilized system displayed anisotropic stability. Using the Cauchy pressure and Poisson’s ratio, the stiffness of the systems was evaluated, with the RS structure proving to be the stiffest. Overall, the findings illuminate the physical properties of RbI, providing valuable insights that could facilitate the creation and refinement of novel materials possessing desirable characteristics.

The suppression of low-frequency waves has been a challenging task for acoustic black hole (ABH) because a small truncation of the ABH tip would fail to prevent the transmission of low-frequency waves below the cutoff frequency. Here, we propose a novel approach to achieve perfect ABH to suppress the wave propagation at low frequencies in the range of 3–100Hz. Structurally, the perfect ABH consists of two ABHs with rigid materials and a soft material connected between the two ABHs to break the cutoff frequency limit and achieve attenuation of up to 21.3dB in the 3–20Hz range. The wave energy focusing effect possessed by ABHs, combined with the impedance mutation on the surface where soft and hard materials are connected, can concentrate the wave energy within the soft material, thus achieving a perfect ABH effect. The proposed perfect ABH compensates the defect that ABH cannot suppress low-frequency and sub-low-frequency waves, and provides the possibility of full-band suppression.

Based on the first principles, the crystal structure, photoelectric properties, and structural stability of two transition metal dichalcogenides (TMDCs) under different strain treatments are systematically calculated. The properties of NbX₂ under tensile and compressive strains are discussed for the first time. Recently, a single-layer 1T structure with X atoms surrounding the transition metal atoms was synthesized in experiments. The 1T multi-forms were octahedral coordination structures, and some of the systems showed excellent semiconductor properties and stability. The results show that NbS₂ has an indirect band gap under different strains and tends to transition to semiconductors which can effectively improve the material activity. NbSe₂ has more excellent properties in the optical field and can be used to manufacture infrared lenses, anti-reflection coatings, and UV reflectors. This study provides a new understanding of the unconventional structure of NbX₂ and provides theoretical guidance for the work in the field of TMDCs.

In this study, hybrid polymer nanocomposites were produced by combining epoxy (EP) with varying amounts of zirconia (ZrO${}_2)$ and yttria (Y₂O${}_3)$ nanoparticles (NPs), reinforced with multi-walled carbon nanotube (MWCNT) and glass fiber (GF). The objective of this study is to develop and examine the performance of EP nanocomposites through hybridization; for this purpose, hardness and impact tests were conducted in accordance with American Society for Testing and Materials (ASTM) standards. Different sets were produced to investigate the effect of used fillers, including EP/ZrO₂, EP/Y₂O₃, EP/MWCNT, EP/GF, EP/ZrO₂/Y₂O₃, EP/MWCNT/ZrO₂/Y₂O₃, and EP/MWCNT/GF/ZrO₂/Y₂O₃. All findings were compared with the net EP sample. The results showed that the EP nanocomposite samples with low NPs content exhibit much higher mechanical performance than net EP. Furthermore, the additions of MWCNT and GF separately at 0.1 and 0.06wt.% have increased the impact strength, respectively, to 165.2% and 338.8%, compared with pure EP. As a result, the presence of MWCNTs and GF in the EP-based nanocomposite matrix could make the product both stronger and tougher.