bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of thermal-fluid coupling in silicon single crystal growth based on gradient normalized physics-informed neural network
Authors: Shi Shuyan , Liu Ding , Huo Zhiran
Published: May 2024

The thermal-fluid coupling phenomenon of silicon melt is significant in the growth process of silicon single crystals. Complex convection affects the temperature and concentration distribution of the silicon melt. Therefore, establishing and solving the thermal-fluid coupling model of silicon melts is crucial to optimizing the crystal growth process and improving crystal quality. Traditional numerical simulation methods have limitations in regard to optimization, control, and real-time monitoring. Physics-Informed Neural Network (PINN) does not require model discretization, after training, it can make predictions quickly, showing potential for industrial applications. However, when solving practical industrial coupling models, PINN often struggles to converge due to large parameter values and significant gaps between solution variables. Moreover, solving the thermal-fluid coupling model with PINN can be treated as a multitask problem, where the gradients of different equations interfere with each other, leading to gradient confusion, slow convergence, or even divergence. Therefore, this paper proposes a gradient normalized PINN (GNPINN) for solving the thermal-fluid coupling model of silicon melt. GNPINN balances the contribution of each task, ensuring a more equitable training speed between different tasks to stabilize the training process of the coupling model. This paper considers the thermal-fluid coupling model of silicon melt under different rotation conditions. GNPINN can accurately and comprehensively capture the complex temperature, velocity, and pressure distribution of silicon melt compared with other methods. Additionally, the experimental results uncover the flow and heat transfer properties of silicon melt, validating the effectiveness and industrial applicability of GNPINN.
Exploring the photochemistry of OAlOH: Photodissociation pathways and electronic spectra
Authors: Trabelsi Tarek , Francisco Joseph S.
Published: May 2024

This study was focused on the photochemistry of OAlOH and three possible pathways, which were studied with high-level multireference configuration interaction ab initio calculations. We computed cuts of the six-dimensional potential energy surfaces for the ground, the lowest singlet and triplet excited states, and probed the photodissociation mechanisms and the stabilities. The OAlOH electronic spectrum, with an energy reaching 7.15 eV, contained four prominent peaks. Photodissociation to AlO, OH, and AlOH constituted a plausible mechanism within the deep-UV range (λ = 250.4 nm). Our data indicated the photostability of OAlOH in the near-UV‒Vis region, so detection with laser-induced fluorescence is possible. Fluorescence and phosphorescence may occur upon excitation at 363.5 nm. The roles of OAlOH in the photochemical reactions of Al-bearing molecules in the upper atmosphere and VY Canis Majoris are discussed.
Optimizing Cu-alloy surface characteristics through magnetic field-enhanced fs laser treatment
Authors: Dawood Asadullah , Bashir Shazia , Khan Muhmmad Asad , Hayat Asma , Bonyah Ebenezer , Sanderson Joseph H. , Majeed Mehwish , Naz Zarish
Published: May 2024

We report here the effect of the magnetic field on plasma parameters and the surface structuring of the Cu alloy after fs laser irradiation. A Ti:Sapphire (800 nm, 35 fs, 1 KHz) laser is employed at various irradiances (0.011–0.117 PW/cm2) to generate plasma. A Transvers Magnetic Field (TMF) of strength 1.1 T is employed for plasma confinement. All the measurements were performed with and without TMF. The Cu plasma parameters, i.e., excitation temperature (Texc) and electron number sensity (ne), determined by laser-induced breakdown spectroscopy analysis, are higher in the presence of TMF. This magnetic field confinement of Cu plasma was studied analytically by evaluating thermal beta (βt), directional beta (βd), confinement radius (Rb), and diffusion time (td). To correlate Cu-alloy plasma parameters with surface modifications, field emission scanning electron microscope analysis is performed. It reveals the formation of low-spatial-frequency laser-induced periodic surface structures (LIPSSs) and high-spatial-frequency LIPSSs, along with agglomers and nano-rims formation. Distinct and well-defined structures are observed in the presence of a magnetic field. It is concluded that controlled surface structuring can be achieved through magnetic confinement, which enhances key plasma parameters. The technique has the potential for enhancing the fabrication of nano-gratings and field emitters, where spatial uniformity is critically important.
Mapping the transition from quasi-2D to 3D spin textures in NiFe nanomagnets
Authors: Scott J. R. , Atkinson D. , Adeyeye A. O.
Published: May 2024

With increasing interest in understanding and mapping the spin textures within magnetic nanostructures, this work reports a study of the transition from quasi-2D magnetic behavior in thin-film ferromagnetic nanostructures to 3D thick-film nanostructures. A series of arrays of 480 × 250 nm2 elliptical Ni81Fe19 nanomagnets patterned using deep ultraviolet (DUV) lithography with thickness (t) ranging from 20 to 250 nm were studied. It is shown through magnetometry and micromagnetics that as the film thickness increases, the nanomagnets transition from effectively planar 2D magnets, with uniform spin textures extending through the film thickness for t ≤ 50 nm, to 3D nanomagnets with more complex non-uniform 3D spin textures for t ≥ 100 nm. These results demonstrate that the fabrication of thick-film nanomagnets via DUV lithography is a viable route to producing consistent 3D magnetic nanostructures for potential applications, such as magnonics.
Professional realism in practice
Authors: Gałuskina Ksenia , Sycz-Opoń Joanna
Published: May 2024

This article describes an attempt to introduce the elements of collaboration into translator training in the form
of a multi-stage translation project. The project was carried out during regular translation classes with the participation of 70
students (translating from Italian, French, or English into Polish). The project comprised the following stages (as prescribed by
two standards: ISO 17100:2015 and ISO/TS 11669:2012). Stage 0: Project preparation (pre-production) – terminological work/dialogue
list preparation; Stages 1 and 2: Translation and check of one’s own translation; Stage 3: Revision – work on bilingual texts –
general correction; Stage 4: Review – work on TL texts – focus on factual errors; Stage 5: Proofreading – work on TL texts – focus
on linguistic errors; Stage 6: Final verification and release. Each student was asked to work on a different text at each stage.
The platform for exchanging files between the students was Trello, an online task management tool. The aim of the classes was to
broaden the students’ view of the current translation market through hands-on experience and to develop their teamwork skills.
This article presents the proceedings of the classes, the results of the opinion survey distributed among the participants, and
discusses the potential difficulties.
Bilateral comparison of 1.018 V and 10 V standards between INRIM (Italy) and the BIPM, November to December 2023 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)
Authors: Solve S , Chayramy R , Stock M , Durandetto P , Enrico E
Published: May 2024

Main text

As part of the ongoing BIPM key comparison BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the INRIM (Italy), from November to December 2023. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_7 (Z7) and BIPM_9 (Z9), were transported by freight to the INRIM and back to the BIPM. In order to keep the Zeners powered during their transportation phase, two additional external batteries were connected in parallel to the internal battery. At the INRIM and the BIPM, the reference standard for DC voltage is a Programmable Josephson Voltage Standard (PJVS). The output electromotive force (EMF) of each travelling standard was measured by direct comparison with the primary standard. The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by the INRIM, at the level of 1.018 V and 10 V, at the INRIM, UINRIM, and those assigned by the BIPM, at the BIPM, UBIPM, at the reference date of the 1st of December 2023.

U
INRIM - U
BIPM = -0.04 µV; u
c = 0.03 µV, at 1.018 V

U
INRIM - U
BIPM = -0.18 µV; u
c = 0.19 µV, at 10 V

where uc is the combined standard uncertainty associated with the measured difference, including the uncertainty of the realisation of the volt at the BIPM and at the INRIM, and the uncertainty related to the comparison.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Bilateral comparison of 1.018 V and 10 V standards between SASO-NMCC (Saudi Arabia) and the BIPM, September to November 2023 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)
Authors: Solve S , Chayramy R , Stock M , Alrobaish A , Aljomaie A
Published: May 2024

Main text

As part of the ongoing BIPM key comparison BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the SASO-NMCC (Saudi Arabia), from September to November 2023. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_E (ZE) and BIPM_F (ZF), were transported by freight to the SASO-NMCC and back to the BIPM. In order to keep the Zeners powered during their transportation phase, a voltage stabiliser developed by the BIPM was connected in parallel to the internal battery. At the SASO-NMCC and the BIPM, the reference standard for DC voltage is a Programmable Josephson Voltage Standard (PJVS). The output electromotive force (EMF) of each travelling standard was measured by direct comparison with the primary standard. The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by the SASO-NMCC, at the level of 1.018 V and 10 V, at the SASO-NMCC, USASO-NMCC, and those assigned by the BIPM, at the BIPM, UBIPM, at the reference date of the 30th of September 2023.

U
SASO-NMCC - U
BIPM = 0.06 µV; uc = 0.05 µV, at 1.018 V

U
SASO-NMCC - U
BIPM = 0.22 µV; uc = 0.12 µV, at 10 V

where uc is the combined standard uncertainty associated with the measured difference, including the uncertainty of the realisation of the volt at the BIPM and at the SASO-NMCC, and the uncertainty related to the comparison.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Gauge-invariant formulation for the gravitational wave equations
Authors: Harada Junpei
Published: May 2024

A gauge-invariant formulation for the gravitational wave equations is presented. Using this approach, weak, plane wave solutions in a vacuum are derived in various theories. These include general relativity with two modes of polarization with helicity ±2, Yang’s theory with three modes of polarization with helicity ±2 and 0, and so-called ‘general metric theories’ with six modes of polarization with helicity ±2, ±1, and two 0s. To identify the polarizations of gravitational waves, it is explicitly demonstrated how the gauge-invariant approach reproduces the earlier results.
Higher-order topological states in T-graphene and their realization in photonic crystals
Authors: Yan Liang , Wang Zhigang , Yan Jie-Yun
Published: May 2024

Higher-order topological states extend the power of nontrivial topological states beyond the bulk-edge correspondence. Here we study the higher-order topological states (corner states) in an open-boundary two-dimensional T-graphene lattice. Unlike the common zero-energy corner states, our findings reveal non-zero energy corner states in such lattice systems, and the energy could be controlled by modifying the hopping parameters. Moreover, the corner states could be transferred away from the lattice corners by designing the position-specific vacancy defects. The strong robustness of the corner states is also demonstrated against the uniaxial strain and vacancy defects, respectively. A plasmonic crystal is constructed to testify to the theory, in which the corner states are realized in optical modes and their higher-order topological properties are verified. Our results open the avenue of corner-states engineering, which holds significant physical implications of higher-order topological states for the design of photonic and electronic devices with specialized functionalities.
A multi-head self-attention autoencoder network for fault detection of wind turbine gearboxes under random loads*
Authors: Yu Xiaoxia , Zhang Zhigang , Tang Baoping , Zhao Minghang
Published: May 2024

Wind turbine gearboxes work under random load for extended periods of time, and the fault detection indicator constructed by the existing deep learning models fluctuate constantly due to the load, which is easy to cause frequent false alarms. Therefore, a multihead self-attention autoencoder network is proposed and combined with a dynamic alarm threshold to detect faults in a wind turbine gearbox subjected to random loads. The multiheaded attention mechanism layer enhances the feature-extraction capability of the proposed network by extracting global and local features from input data. Furthermore, to suppress the influence of the random load, a dynamic warning threshold was designed based on the reconstruction error between the inputs and outputs of the proposed network. Finally, the effectiveness of the proposed method was verified using the vibration data of wind turbine gearboxes from an actual wind farm.
Integral reinforcement learning-based event-triggered optimal tracking control for modular robot manipulators via non-zero-sum game
Authors: Dong Bo , Ding Zhendong , An Tianjiao , Cui Yiming , Zhu Xinye
Published: May 2024

Under an event-triggered mechanism, a non-zero-sum (NZS) game optimal tracking control method for modular robot manipulator (MRM) systems with input constraints is proposed using the adaptive dynamic programming (ADP) method based on integral reinforcement learning (IRL). First, a dynamic model of the MRM system is developed based on joint torque feedback technology, consisting of an n-joint subsystem related to interconnected dynamic coupling (IDC). Second, we design a robust compensation controller to handle the known model term and an optimal compensation controller to deal with the uncertainty term caused by the IDC and friction, respectively. In addition, a nonlinear disturbance observer is established to dispose of the negative effects caused by the uncertain sensor output disturbance. Third, based on differential game theory, we transform the optimal tracking control problem of the MRM system into an n-player NZS game problem. Then, the IRL-based ADP method is adopted, which relaxes the need for system partial unknown dynamic information, and only a critic neural network is used to solve the coupled Hamilton–Jacobi equation, so as to obtain the optimal control policy. Then, using Lyapunov theory, the tracking error of the MRM system is demonstrated to be uniformly ultimately bounded. Finally, the effectiveness and superiority of the proposed algorithm are verified through experiments.
A strategy to build a library of oil tracers by oleophilic silica-encapsulated DNA nanoparticles
Authors: Deng Jinxin , Li Na , Yang Shuangyu , Qin Mei , Guo Yuen , Feng Yuchen , Ye Xinya , Li Chongying
Published: May 2024

Artificially synthesized DNA is involved in the construction of a library of oil tracers due to their unlimited number and no-biological toxicity. The strategy of the construction is proposed by oleophilic Silica-encapsulated DNA nanoparticles, which offers fresh thinking in developing novel tracers, sensors, and molecular machines in engineering & applied sciences based on artificially synthesized DNA blocks.
Adsorption and dissociation of hydrogen molecules over S-vacancies in a Nb-doped MoS2 monolayer
Authors: Irusta Yako , Morón-Navarrete Guillermo , González César
Published: May 2024

Motivated by the recent interest in the hydrogen energy, we have carried out a complete study of the catalytic activity of a defective molybdenum disulfide monolayer (MoS2) by means of density functional theory (DFT) calculations. The MoS2 monolayer is characterized by a nonreactive basal plane. In principle, its catalytic activity is concentrated at the edges, but an alternative way to increase such activity is obtained by creating active sites where the molecules can dissociate. These defects can be easily produced experimentally by different techniques. In our study, we have performed an atomic, energetic and electronic analysis of a hydrogen molecule adsorbed on a MoS2 monolayer. In a first step, we have found that the H2 molecule remains physisorbed over both doped-free and Nb-doped MoS2 monolayers, showing that the Nb atom does not increase the poor reactivity of the clean MoS2 layer. Interestingly, our energetic results suggest that the vacancies will prefer to be formed close to the Nb atoms in the doped monolayer, but the small energy difference would allow the formation in non-doped like sites. Theoretically, we found out the conditions for the molecular dissociation on a S vacancy. In both cases, with and without Nb, the molecule should rotate from the original perpendicular position to an almost parallel orientation jumping an energetic barrier. After that, the atoms are separated binding to the Mo atoms around the missing S atom. Our ab initio molecular dynamics simulations show that for low pressure conditions (using one single molecule in the system) the H2 prefers to desorb from the vacancy, while for larger pressures (when additional H2 molecules are added to the system) the molecule is finally dissociated on the vacancy. Our long simulations confirm the great stability of the structure with the two H atoms binding to the Mo atoms close to the vacancy. Finally, the inclusion of a third (or a fourth) H atom in the vacancy leads to the formation and desorption of a H2 molecule, leaving one (or two) atoms in the vacancy.
Influence of chemical treatment and interaction with matrix on room temperature phosphorescence of carbon dots
Authors: Arefina Irina A , Erokhina Daria V , Ushakova Elena V
Published: May 2024

In this work, composite materials were formed based on various matrices (polymer and porous cellulose matrix) and carbon dots (CDs) with intense room-temperature phosphorescence (RTP). The effect of post-synthesis chemical treatment with citric acid or urea on the optical properties of composites was studied: the increase in carboxy and carbonyl groups led to an increase of RTP signals that could be seen with the naked eye over several seconds. The fabricated composites demonstrated good stability and reversibility of RTP signals by mild heating. Based on the developed CDs, luminescent inks were used for a simple demonstration of the data encryption on paper.
Preparation and properties of two-dimensional Ti2CT
x
MXene based on electroetching method
Authors: Liu Ruixue , Wei Sainan , Shi Bao , Ma Yizhi , Sun Luning , Wang Wei
Published: May 2024

The continuous advancements in wearable electronics have drawn significant attention toward 2D MXenes materials for energy storage owing to their abundant availability, adaptability, and distinctive physicochemical properties. Two unresolved concerns currently revolve around environmental pollution by F-containing etching and finite kinetics caused because of re-stacking of nanosheets. In this study, Al was electrochemically etched from porous Ti2AlC electrodes without the use of fluorine, through a selective electrochemical etching process in dilute hydrochloric acid. Subsequently, Ti2CT
x
MXene was vertically grown on carbon fiber (CF) substrates. The resulting Ti2CT
x
@CF electrodes are lightweight, thin, and flexible, exhibiting a surface capacitance of 330 mF cm−2 at a constant current density of 1 mA cm−2 after 2000 cycles. They display a surface capacitance retention of 96.16% and a high energy density of 45.3 μWh cm−2 at a power density of 0.497 mW cm−2. These metrics underscore the Ti2CT
x
@CF electrode’s commendable multifunctionality, electrochemical performance, ion transport efficiency, and charge storage capacity. Moreover, a flexible energy storage electrode material with a high area capacity was developed by combining Ti2CT
x
MXene nanosheets, possessing a large specific surface area, with a flexible carbon fabric substrate.
Synthesis of CS-Fe3O4/GO nanocomposite for adsorption of heavy metal in aqueous environment
Authors: Nguyen Thu Huong , Nguyen Van Doan , Vu Anh-Tuan
Published: May 2024

In this study, magnetic material based on graphene oxide (GO) was developed for enhanced adsorption capacity for heavy metals. The Fe3O4 nanoparticles were combined with the GO material using a chitosan (CS) binder to obtain the CS-Fe3O4/GO nanocomposite. The adsorption capacity of this nanocomposite was evaluated by removing heavy metals including Ni2+ ions. When GO was composed with Fe3O4 and CS, the GO films were densely covered with ferromagnetic particles, which were bound and densely distributed on the GO film surface due to the interaction between GO and CS. The optimal conditions for the complexation of Ni2+ and 4-(2-pyridyl azo)-rezoxine (PAR) are 1 ml Ni2+, 2 ml PAR 100 mg l−1, pH = 6 (adjusted with 0.7 ml of the 0.1 M K2HPO4 solution) and a complexation time of 20 min. After 50 min of adsorption, the Ni2+ removal efficiency of the CS-Fe3O4/GO nanocomposite reached 81.21% and the corresponding adsorption capacity was 2.03 mg g−1 . The Ni2+ removal process followed the first-order model and Freundlich isotherm. This process was spontaneous (ΔG
o < 0) and an exothermic process (ΔH
o = −1128.875 J·mol−1). In addition, the factors affecting this process were investigated, including the pH solution, the dosage of the CS-Fe3O4/GO nanocomposite and the initial Ni2+ concentration. The CS-Fe3O4/GO nanocomposite showed a potential adsorption capacity in removing Ni2+ at low concentrations from wastewater.
Highly sensitive and easy-to-attach wearable sensor for measuring finger force based on curvature changes in an ellipse-shaped finger ring
Authors: Ozaki Takashi , Ohta Norikazu , Fujiyoshi Motohiro
Published: May 2024

Technologies for digitizing worker actions to enhance human labor tasks, mitigate accidents, and prevent disabling injuries have garnered significant attention. This study focuses on monitoring the force exerted by the fingers and developing a wearable fingertip force sensor based on a simple elliptical ring structure in conjunction with a commercially available resistive bend sensor. Resembling a ring accessory, the sensor is easy to attach and detach, and exhibits high sensitivity, with a resistance change of approximately 9% for a fingertip load of 1 N. Furthermore, to mitigate crosstalk during finger flexion, we propose a combined configuration employing this ring-shaped sensor alongside another sensor designed for measuring and rectifying finger flexion angles. Additionally, we introduce an empirically derived fitting function and a straightforward calibration procedure to extract the function’s parameters. The proposed system achieves an average RMS error of 0.53 N for force estimations of approximately 5 N, even during finger flexion and postural changes.
Effects of interface angle, added powder and applied deformation on the transport current and structure of scarf joints of single- and multi-core unreacted MgB2 wires
Authors: Hušek I , Kováč P , Melišek T , Berek D , Kopera L
Published: May 2024

The effects of the interface angle and applied deformation on the transport current and structure of scarf architecture joints between single- and multi-core MgB2 wires are studied in this paper. The transport currents of the joints were measured at 4.2 K, external magnetic fields of 2–8 T, and joint’s resistances between 27 and 42 K. Resistive transitions and critical currents of the prepared joints were compared with the transition and critical current of the unjointed MgB2 wires. The interface structure of joined in situ wires was analysed using optical microscopy. Increasing the interface area between the joined wires and optimizing deformation by pressing allows to enlarge the superconducting current path. In-field transport currents of up to 73% of wire’s I
c were measured for joined single-core MgB2/Fe wires. In the case of six-filament wires, the maximal transport current up to 53% of wire’s I
c was reached. The results show that the presented joint technique could potentially be used for superconducting MgB2 coils in a persistent mode.
Spatial mode conversion of a reflected polarized beam from an isotropic medium at brewster angle
Authors: Hu Hua-Jie , Li He-He , Li Xin-Zhong
Published: May 2024

In this study, the spatial mode evolution of a chiral polarized beam during reflection on an isotropic medium surface at Brewster angle is both theoretically and experimentally investigated. In this process, the topological charge of the reflection field’s horizontal component increases (decreases) by one, relative to the specific left (right) elliptical polarization incident beam. While incident l

i
-order vortex beam is in a certain polarization state, the intensity distribution of the reflection field’s horizontal component appears as the interference pattern of the

l

i

±
1

-order output vortex beams. The conversion occurs between the spin and orbital angular momentum and does not violate the conservation of the total angular momentum. We explain the physical mechanism of this phenomenon using phase shift theorem, and analyze the effect of ellipticity and polarization angle on this physical phenomenon.
Numerical investigation of a THz-driven dielectric accelerator with a Bragg-reflector for accelerating sub-relativistic electron beams
Authors: Xiriai M , Aimidula A , Bake Mamat Ali , Zhang Ping
Published: May 2024

Structure-based novel accelerators exhibit significant potential for substantial reduction in size and associated costs of future accelerators. Utilizing high-power THz sources in dielectric accelerator structures presents a favorable compromise for achieving elevated gradients and alleviating beam injection requirements. We conducted numerical investigations on an energy-efficient dielectric single grating structure accompanied by a Bragg-reflector, employing THz pulses to generate a phase-modified field for accelerating sub-relativistic electron beams. The structural parameters were optimized to enhance the strength of the acceleration field. The simulation results demonstrate that the side-coupling single grating structure, accompanied by a Bragg-reflector, designed for sub-relativistic electron beam acceleration, can increase the relative structural energy efficiency by more than 50% compared to a dual-grating accelerator structure. Moreover, it offers an available maximum acceleration gradient of up to 400 MeV m−1.
Multifunctional terahertz device based on plasmon-induced transparency
Authors: Lei Pengliang , Nie Guozheng , Li Huilin , Li Zonglin , Peng Liang , Tang Xiaofang , Gao Enduo
Published: May 2024

Enhancing light-matter interaction is crucial in optics for boosting nanophotonic device performance, which can be achieved via plasmon-induced transparency (PIT). In this study, a polarization-insensitive PIT effect at terahertz frequencies is achieved using a novel metasurface composed of a cross-shaped graphene structure surrounded by four graphene strips. The high symmetry of this metasurface ensures its insensitivity to changes in the polarization angle of incident light. The PIT effect, stemming from the coupling of graphene bright modes, was explored through finite difference time domain (FDTD) simulations and coupled mode theory (CMT) analysis. By tuning the Fermi level in graphene, we effectively modulated the PIT transparent window, achieving high-performance optical switching with a modulation depth (88.9% < MD < 98.0%) and insertion losses (0.17 dB < IL < 0.51 dB) at a carrier mobility of 2 m2/(V·s). Furthermore, the impact of graphene carrier mobility on the slow-light effect was examined, revealing that increasing the carrier mobility from 0.5 m2/(V·s) to 3 m2/(V·s) boosts the group index from 126 to 781. These findings highlight the potential for developing versatile terahertz devices, such as optical switches and slow-light apparatus.
Absorption enhancement in silicon-based dielectric resonator for quad-band terahertz biosensing
Authors: Gupta Raj Kumar , Maurya Jitendra Bahadur
Published: May 2024

A technique is implemented to obtain the multi-band perfect absorption (nearly 100%) in an ultrathin silicon-based dielectric resonator (DR) using perturbation. A silicon-based plus-shaped resonator is utilized to design the proposed absorber which provides the four narrow-band absorptions at frequencies of around 5.75, 6.14, 6.48, and 7.24 THz with the level of absorption 54%, 20%, 95%, and 96%, respectively. The plus-shaped resonator is perturbed by cutting slot of plus shape in such a way that it obtains perfect absorption with sufficient guard-band to prevent the multi-band interference in each band. This perturbation provides four absorption peaks at frequencies of around 5.80, 6.27, 6.80, and 7.23 THz, with highly improved absorption in all the bands, i.e., 99.84%, 99.78%, 99.51%, 98.42%, respectively. The ultranarrow absorption peaks with narrow FWHM are suitable for the application of THz biosensing and refractive index analysis. The performance of the proposed absorber is studied with the variation in refractive index of sample. It is found that the proposed absorber provides the high sensitivity 0.186, 0.29, 0.2485, 0.43 THz RIU−1 and quality factor 280, 185.79, 320.42, and 131.51 for different bands, respectively. The proposed absorber performance is also studied for various THz biosensing applications like the detection of various viruses, malaria, and cancer in the human body at various stages.
Super dense coding out of thermal equilibrium
Authors: Javed Seerat , Tayyab Ansha , Shaukat Muzzamal I
Published: May 2024

We have examined the potentiality of superdense coding for a quantum system placed out of thermal equilibrium. To this aim, the dynamics of two two-level quantum systems are analyzed and explicit expressions for transition rates are evaluated. The dependence of superdense coding capacity on initial states is observed and examined for different ratios of anti-symmetric to symmetric transition rates. The effect of sub-radiant and super-radiant terms is interpreted. The validity of dense coding is also analyzed for different probability amplitudes and it is perceived that maximally entangled states show the highest degree of coding capacity. Moreover, the optimal time of coding capacity is greatest for initially entangled state. This strategy can be relevant to analyze further applications out of thermal equilibrium.
Laboratory simulation to study the nonlinear evolution of right-hand circularly polarised wave in laser-produced plasmas
Authors: Aditya  , Sharma Suresh C , Singh Indraj , Sharma R P
Published: May 2024

To simulate the astrophysical scenarios at the scale of laboratory astrophysics, the interaction of high-power lasers with plasmas is increasingly being used. So, in this perspective, a nonlinear wave-wave interaction between right-hand circularly polarised wave (R-mode wave) and electron plasma wave (EPW) is proposed to understand the localization of the pump R-mode wave and associated magnetic turbulence at electron scale in magnetized plasma relevant to laboratory astrophysics. The ponderomotive force and relativistic variation of electron mass are accountable for this nonlinear wave-wave interaction model. For this nonlinear dynamics, coupled model equations for EPW and R-mode wave are developed and solved by laboratory simulations utilizing finite difference and pseudo-spectral methods. The observed simulation findings, like the nonlinear evolution of the pump wave, typical scale size of the formed localized structures, and electron scale turbulent spectra associated with the coherent structures resemble various laboratory and space plasma scenarios. A semi-analytical model in the paraxial limits is also developed to understand the physics behind the localization process of the pump wave inside the plasma medium.
Dynamics of transformed nonlinear waves for the (2+1)-dimensional pKP-BKP equation: interactions and molecular waves
Authors: Zhang Lihan , Zhao Zhonglong , Zhang Yufeng
Published: May 2024

In this paper, the dynamical behaviors of transformed nonlinear waves for the (2+1)-dimensional combined potential Kadomtsev-Petviashvili and B-type Kadomtsev-Petviashvili (pKP-BKP) equation are investigated, which can be used to reveal the nonlinear wave phenomena in nonlinear optics, plasma physics and hydrodynamics. The breath-wave and the lump solutions are constructed by means of the soliton solutions. The conversion mechanism for the breath-wave is systematically analyzed, which leads to several new kink-shaped nonlinear waves. The gradient relationships of these transformed waves are revealed by a Riemannian circle. Through the analysis of the nonlinear superposition between the periodic wave component and the kink solitary wave component, the dynamical characteristics including the formation mechanism, oscillation and locality for the nonlinear waves are investigated. The time-varying properties of transformed waves are shown by the study of time variables. By virtue of the two breath-wave solutions, several interactions including elastic and inelastic collisions between two nonlinear waves are studied. In particular, some transformed molecular waves encompassing the non-, semi- and full-transition modes are presented with the aid of velocity resonance. The results can help us further understand the complex nonlinear waves existing in the integrable systems.
Angular bispectrum and trispectrum of scalar-induced gravitational waves: all contributions from primordial non-Gaussianity fNLand gNL
Authors: Li Jun-Peng , Wang Sai , Zhao Zhi-Chao , Kohri Kazunori
Published: May 2024

Studying the primordial non-Gaussianity of inflationary perturbations is crucial for testing the inflation paradigm of the early universe. In this work, we conduct a comprehensive analysis of the angular bispectrum and trispectrum of scalar-induced gravitational waves (SIGWs) in the presence of local-type primordial non-Gaussianity parameterized byfNLandgNL, deriving their semi-analytical formulae for the first time. Our findings indicate that it is the presence of primordial non-Gaussianity that leads to a non-Gaussian SIGW background, suggesting that the angular bispectrum and trispectrum of SIGWs could serve as probes of the primordial non-Gaussianity. Our numerical results further illustrate thatfNLandgNLexert significant impacts on the spectral amplitudes, potentially reaching up to 10-5for the former and 10-8for the latter. In particular, we demonstrate that the angular bispectrum and trispectrum exhibit characteristic dependence on the angular multipoles and frequency bands. They hold potentials to be measured by gravitational-wave detectors that may advance our understanding of the origin of the universe.
Cosmological implications of gauged U(1)
B-L
on ΔN
eff in the CMB and BBN
Authors: Esseili Haidar , Kribs Graham D.
Published: May 2024

We calculate the effects of a light, very weakly-coupled boson X
arising from a spontaneously broken U(1)
B-L
symmetry
on ΔN
eff as measured by the CMB and
 Yp
from BBN.
Our focus is the mass range
1 eV ≲ mX
≲ 100 MeV;
masses lighter than about an eV have strong constraints from
fifth-force law constraints, while masses heavier than about
100 MeV are constrained by other probes, including terrestrial
experiments.
We do not assume N
eff began in thermal equilibrium with the SM;
instead, we allow N
eff to freeze-in from its very weak interactions
with the SM. We find U(1)
B-L
is more strongly constrained
by ΔN
eff than previously considered. The bounds
arise from the energy density in electrons and neutrinos slowly
siphoned off into N
eff bosons, which become nonrelativistic,
redshift as matter, and then decay, dumping their slightly larger
energy density back into the SM bath causing ΔN
eff > 0.
While some of the parameter space has complementary
constraints from stellar cooling, supernova emission, and
terrestrial experiments, we find future CMB observatories
including Simons Observatory and CMB-S4 can access regions of mass
and coupling space not probed by any other method.
In gauging U(1)
B-L
, we assume the [U(1)
B-L
]3 
anomaly is canceled by right-handed
neutrinos, and so our ΔN
eff calculations have been
carried out in two scenarios: neutrinos have Dirac masses, or,
right-handed neutrinos acquire Majorana masses.
In the latter scenario, we comment on the additional implications
of thermalized right-handed neutrinos decaying during BBN.
We also briefly consider the possibility that X decays
into dark sector states. If these states behave as radiation,
we find weaker constraints, whereas if they are massive,
there are stronger constraints, though now from
ΔN
eff < 0.
Mutual information between galaxy properties and the initial predisposition
Authors: Moon Jun-Sung , Lee Jounghun
Published: May 2024

The immense diversity of the galaxy population in the universe is believed to stem from their disparate merging and star formation histories, and multi-scale
influences of diverse environments. No single causal factor of the initial state is known to explain how the galaxies formed and evolved to end up
possessing such various traits as they have at the present epoch. However, several observational studies have revealed that the key physical properties of the observed
galaxies in the local universe appeared to have a much simpler, lower-dimensional correlation structure than expected, the origin of which remains unexplained.
Speculating that the emergence of such a simple correlation structure of the galaxy properties must be triggered by nature rather than by nurture,
we explore if the present galaxy properties may be correlated with the initial precondition for protogalaxy angular momentum, τ, and test it against the data
from the IllustrisTNG300-1 hydrodynamic simulation. Employing Shannon's information theory, we discover that τ shares a significantly large amount of mutual information
with each of the four basic traits of the TNG galaxies at z = 0: the spin parameters, formation epochs, stellar-to-total mass ratios, and fraction of kinetic energy in ordered rotation.
These basic traits except for the stellar-to-total mass ratios are found to contain even a larger amount of MI about τ than about the total masses and environments
for the case of giant galaxies with 11.5 ≤ log[M
t/(h
-1
M
⊙)] < 13. Our results imply that the initial condition of the universe must be more impactful on the galaxy
evolution than conventionally thought.
Surface evolution of thermoelectric material KCu4Se3 explored by scanning tunneling microscopy
Authors: Xia 夏 Yumin 玉敏 , Ma 马 Ni 妮 , Cai 蔡 Desheng 德胜 , Liu 刘 Yuzhou 宇舟 , Gu 谷 Yitong 易通 , Yu 于 Gan 淦 , Huo 霍 Siyu 思宇 , Pang 庞 Wenhui 文慧 , Xiao 肖 Chong 翀 , Qin 秦 Shengyong 胜勇
Published: May 2024

Novel two-dimensional thermoelectric materials have attracted significant attention in the field of thermoelectric due to their low lattice thermal conductivity. A comprehensive understanding of their microscopic structures is crucial for driving further the optimization of materials properties and developing novel functional materials. Here, by using in situ scanning tunneling microscopy, we report the atomic layer evolution and surface reconstruction on the cleaved thermoelectric material KCu4Se3 for the first time. We clearly revealed each atomic layer, including the naturally cleaved K atomic layer, the intermediate Se2− atomic layer, and the Se− atomic layer that emerges in the thermodynamic-stable state. Departing from the majority of studies that predominantly concentrate on macroscopic measurements of the charge transport, our results reveal the coexistence of potassium disorder and complex reconstructed patterns of selenium, which potentially influences charge carrier and lattice dynamics. These results provide direct insight into the surface microstructures and evolution of KCu4Se3, and shed useful light on designing functional materials with superior performance.
Factor analysis method for delay dynamics in Nigerian Tin Can Island Port for sustainable development
Authors: Odetunmibi O. A. , Oke K. Z. , Alabi R. E. , Agboola O. O. , Adedotun A. F.
Published: May 2024

The effect of efficient and effective port system on the economy viability of any nation cannot be over emphasis. This study investigated factors that could be termed as delay causative factors in Nigerian ports industry using TIN CAN Island port complex as a case study. A well-structured questionnaire was developed for this research and 72 respondents, who are port users (custom officers, employees, and customers), were asked to rank the variables perceived to be causing delay at the port according to their respective perception of the effect of each factor on delay factors at the port. The validity of the research instrument was done using Cronbach Alpha. There are several factors that were thought to be working together in reducing efficiency in Nigerian ports and these factors were analyzed using factor analysis method. It was discovered from the analysis that Lack of Government Authority, Ullage Constraint, Inadequate Berthing, Logistics Delay, Financial Constraint and Equipment Breakdown are major factors that cause delay at Tin Can Island Port Lagos. These highlighted factors should be paid special attention in order to reduce delay in Tin Can Island port which will in turns lead to more revenue for the country.
Utilization and application of bioactive compounds generated from Fish waste and by product as Functional Food Ingredient: A review
Authors: Olaniran A. F. , Adeoye O. E. , Oyadeyi O. M. , Okonkwo C. E. , Erinle O. C. , Malomo A. A. , Iranloye Y.M. , Olaniran O. D. , Faloye O. R
Published: May 2024

The quest for novel functional food ingredients from natural sources is one of the most important discuss in food science and technology. Food industries dispose their valuable waste and some food industries re-process their wastes and used them as functional food ingredients, thereby developed their economy to survive in the neck cutting competition of the market. Enormous volumes of food processing by-products (FPBs) are produced from food manufacturing industries, accounting it as the second-largest quota of food waste generation. Fish known as ‘rich food for poor people,’ supplies good quality of fats, minerals vitamins and proteins to billions of populaces across the globe. However, the fish processing industry on daily basis generates huge wastes leading to the quest for management of these wastes. These wastes which can be referred to as by-products are generated during removal of head; gutting of the fish and during other secondary processing carried out either onboard in fishing vessels or at processing plants on the shores. Over the years there are bids for utilization of fish wastes and by products for production of functional food ingredients using bioactive compounds produced from them. This was aimed at reduction of processing waste, creation of sustainable economic boost, environmental safety while formulating value added functional food which could be of importance to human and animal health or wellbeing. By-products from fish processing such as blood, fleshy chunks of fatty fish, tails, liver from white lean fish, Fish heads, offal, viscera (gut, intestines, etc.), skin and shells have potentials utilization as raw materials for production of value-added functional food ingredients. Bioactive peptides isolated from various fish protein hydrolysates have reported to have several bioactivities such as immunomodulatory, antioxidative antihypertensive, antithrombotic, anticoagulant activities among others Hence from the review, the recovery of bioactive compound and utilization of these by-products are untapped sources for functional ingredients which can be applied in several aspects of food processing for the benefit of manufactures, supply series of nourishments, and consequently advancing the usefulness of the fish waste in consumers’ health and economic benefits of all stakeholders.
Application of VLF-EM response and geoelectrical sounding in groundwater investigation around an active dumpsite
Authors: Adeniji A. A. , Ajani O. O. , Adagunodo T. A. , Ojo O. F.
Published: May 2024

An integrated geophysical method combining very low frequency electromagnetic (VLF-EM) and vertical electrical sounding (VES) methods were carried out around Adaland, Southwestern Nigeria, located within latitude 7° 54’ 0” and longitude 4° 43’ 0”, with a view to investigate the possible impact of dumpsite on groundwater. This is the major study in the environment to offer extensive evidence regarding the suitability of obtaining quality groundwater. In this research, eight VLF-EM and twelve VES data sets were generated, which were then used to estimate the linear structure, bedrock formation, subsurface geological characteristics, and identification of leachate pathways. The VLF-EM data were analyzed by employing Karous_Hjelt and Microsoft Excel, while the VES data were investigated using the WinRESIST software. TheVLF-EM results confirmed the presence of conductive zones, which might be due to fracture, fault and contact zones or weathered basements. The lithological units acquired from the electrical resistivity results revealed four geoelectrical layers such as topsoil, weathered-based, fractured basement and fresh basement. However, the identified weathered layers and fractured basements from the geoelectrical sections and the corresponding Karous and Hjelt (K-H) pseudo sectionresults around the dumpsite, constitute the main passages for the possible impact of the open dumpsite on groundwater quality, since leachates from the dumpsite could slowly percolate downwards from the topsoil to the water table. Therefore, the impact of the dumpsite on the groundwater is caused by the inadequate clay materials, near-surface features such as fractures/faults, and lateral in-homogeneity. Thus, integrating both methods has been recommended in site characterization for accessing quality groundwater around a dumpsite environment.
Seasonal Variation of Total Attenuation between Airborne Platform and Earth Station in South-West Region, Nigeria
Authors: Arijaje T. E. , Omotosho T. V. , Aizebeokhai A. P. , Akinwumi S. A.
Published: May 2024

The seasonal variation of total attenuation in the southwest region of Nigeria has been computed using eight (8) years dataset at Ku- and Ka-band of the transmitted power of the radar, transmitted antenna gain and the received antenna gain of the satellite retrieved from the archived of the GPM. The results obtained fluctuates between the seasons at Ku- and Ka-band. From the results obtained at Ku-and Ka-band, the results from analysis showed that the peak total attenuation was recorded between the early (MAM) and late wet (JJA) season when the intensity of rainfall is maximum in the South-West region. As a result, the effect on the airborne-earth station link will be severe which may further lead to signal outage. However, the state where the highest total attenuation was consistent is Lagos state. These seasons and Lagos state must be taking into consideration by engineers and radiowave propagation group when planning and sitting radiowave propagation in the study area.