bluuebunny/crossref_metadata_2025 huggingface dataset:
Gravitational instability of nonuniformly rotating and magnetized viscoelastic fluid with dissipative effects
Authors: Dhiman Joginder Singh , Mahajan Mehak
Published: January 2024

In this paper, the effect of dissipative energy arising from bulk-viscosity on the collapse of a self-gravitating viscoelastic medium permeated with a nonuniform magnetic field and rotation is analyzed using the standard Jeans mechanism. A local solution of the system of nondimensional linearized perturbation equations, having variable coefficients, is obtained using the normal modes analysis method. The Jeans instability criteria are derived from the characteristic equation (valid under the kinetic and hydrodynamic limits) for parallel and perpendicular wave propagation, modified due to bulk viscosity and Alfvén wave velocity. From the calculated critical values of Jeans wavenumber, it is found that the bulk-viscosity and magnetic field have stabilizing influence on the onset of gravitational instability for each mode of wave propagation. It is observed that the nonuniform rotation does not affect the instability criterion, however, the rotation strongly suppresses the growth rate of the Jeans instability in both the hydrodynamic and kinetic limits. Also, a comparison of the impact of various rotational and magnetic field orientations on the growth rate in viscoelastic fluid is also presented. From the analysis, it is also observed that the presence of dissipative energy reduces the growth rate, in both modes of wave propagation.
EXPERIMENTAL INVESTIGATION ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DSS2205 AND SS304L DISSIMILAR WELDMENTS
Authors: MURUGAN M. , SELVAKUMAR G. , RAMKUMAR T. , SELVAKUMAR M.
Published: January 2024

This paper outlines the TIG welding process without using active flux for 4[Formula: see text]mm-thick plates of duplex stainless steel (DSS 2205) and austenitic stainless steel (SS 304L). It also provides the properties and behavior analysis of weldments. Complete penetration is achieved with multi-pass welding. The microstructure is examined using an optical microscope (OM) and a scanning electron microscope (SEM). It was used to report on the differences between the unpolished zone and the heat-affected zone (HAZ) in weldments. A Vickers hardness tester (HV scale 10) was used to assess the weldment’s hardness. Tensile and bend failure were among the mechanical properties exhibited by the parent metals of DSS2205, SS304L, and dissimilar junctions. The findings demonstrated shallow gaps in the surface area and a greater ultimate tensile strength of 600[Formula: see text]MPa for DSS similar welding. However, compared to other similar weldments, dissimilar weldments exhibit superior performance in bending conditions.
The growth aspects and experimental techniques for the characterization of amino acid L-histidine hybrid crystals for nonlinear optical device applications
Authors: Merina Albert Helen , Satya Sagar P. , Sai Chandra J. , Manoj Kumar Nellore , Madhuri Sailaja J. , Kalyan Chakravarthi M. , Srinivasa Rao Ganimisetti , Alosious Gonsago C.
Published: January 2024

The development of crystal growth and measurement methods opens new possibilities for studying materials with remarkable nonlinear optical features. The development of bulk crystals is a constant concern to be beneficial for device applications. This study focuses on the development of nonlinear optical crystals of L-histidine complexes, characterization approaches, and prospective applications. The solution growth approach, a straightforward, inexpensive, and low-temperature growth technique, was adopted broadly. Recent studies show that L-histidine derivatives have potential optical, SHG, thermal, dielectric, and mechanical properties, making them an excellent choice for nonlinear optical devices. In this work, structural, spectroscopic, chemical composition, linear and nonlinear optical analyses, thermal, and dielectric characterizations of L-histidine derivatives were conducted. Most of the L-histidine complexes were found to be crystallized in orthorhombic and monoclinic crystal systems with P212121 and P21 space groups. The crystalline perfections of the samples were analyzed by the HR-XRD method. The energy-dispersive X-ray (EDX) spectroscopic technique was applied to evaluate the chemical content of the compounds. FT-IR and FT-Raman techniques were used to recognize the molecular vibrations and functional groups of the L-histidine derivatives. The UV-visible and photoconductivity studies were done to examine the optical behaviors of the developed crystals. Most of the crystals were found to have excellent optical transparency and wide bandgaps. It has been observed that L-histidine hydro-fluoride dehydrate and L-histidine tetrafluoroborate are found to have the highest second harmonic generation (SHG) efficiencies. The dielectric analyses were utilized to study the dielectric constant and dielectric loss variations with the applied frequency. According to the thermal analyses, most of the crystals were found to have substantial thermal stabilities suitable for device applications.
PARAMETER ESTIMATION METHODS OF REQUIRED RATE OF RETURN ON STOCK
Authors: GANKHUU BATTULGA
Published: January 2024

In this study, we introduce new estimation methods for the required rate of returns on equity of private and public companies using the stochastic dividend discount model (DDM). To estimate the required rate of return on equity, we use the maximum likelihood method, the Bayesian method, and the Kalman filtering. We apply the model to a set of firms from the S&P 500 index using historical dividend and price data over a 32-year period. Overall, the suggested methods can be used to estimate the required rate of returns.
Analysis of Torsional Vibration in a Fractured Poroelastic Half-Space Coated with Metal Foam and Sliding Interfaces
Authors: Pramanik Dipendu , Manna Santanu
Published: January 2024

Metal foams are highly useful in industries because of their lightweight, energy and vibration absorption properties. This study investigated the propagation of torsional waves in an elastic layer over a fluid-saturated fractured poroelastic half-space with a metal foam coated layer. It is assumed that the interfaces are in sliding contact with two different sliding parameters. The coated layer is closed-cell aluminium foam. We use the separation variable technique and the Bessel function to solve the equation of motion in different layers. The displacement components are written in terms of the second kind Whittaker functions. Using an asymptotic formulation of the Whittaker function and appropriate boundary conditions, the dispersion equation is derived in terms of the determinant. The control of the vibration due to the metal foam-coated layer is one of the important goals of this study. Also, numerical and graphical analyses have been done with the help of Mathematica software to see the effect of different parameters on torsional wave propagation. It is found that the presence of coated metal foam layer decreases the phase velocity of the torsional wave propagation. The work may be helpful in the seismology, automobile, and aerospace industries.
Dynamic “Disengagement-Closure” Contact Characteristics of Track–Bridge Interface Caused by High-Speed Train Under Side Pier Settlement
Authors: Feng Yulin , He Shuai , He Binbin , Jiang Lizhong , Zhou Wangbao
Published: January 2024

A nonlinear dynamic model of a train–bridge-longitudinal track coupling system considering the dynamic contact of the bridge–track interface (BTI) is established. Based on the previously established BTI contact characterization model and train–bridge coupling joint simulation model, the proposed model is verified from both static and dynamic perspectives. Accordingly, the dynamic displacement variation law of the bridge–track structure before, during and after the train passing through the side pier settlement area, the additional stress dynamic variation law and the interlayer connection dynamic variation law are analyzed. Moreover, the amplification effect of the wheel repeated “beating effect” on the dynamic contact force of “disengagement-closure-redisengagement” of the BTI void area is also analyzed. The results show that the accuracy of the proposed model can be verified from both static and dynamic perspectives. During the train passes through the settlement area, the dynamic deformation of track is the largest. Before and after the train passes through the settlement area, the dynamic deformation of track is basically the same. During the train passes through the settlement area, the BTI completes a dynamic contact process of “disengagement-closure-redisengagement”. The static effect of the side pier settlement on the dynamic bonding force of sliding layer is much larger than the dynamic effect of the train load. The dynamic effect of the train load is much larger than the static effect of the side pier settlement on the dynamic bonding force of the CA mortar and fasteners. The side pier settlement has a dynamic amplification effect on the train wheelset. Along the mileage direction, there are interface voids and contact areas in the dynamic bonding force of sliding layer and CA mortar, while there are no voids and contact areas in the dynamic bonding force of fasteners.
Comparison Study of the Location-Related Damage Sensitivity and Structural Damage Index with Sensitivity Enhancement for Beam Structure
Authors: Li Panjie , Zhao Tongkuai , Zhang Jian , Li Jinke , Li Shengli
Published: January 2024

The primary requirement for vibration-based structural damage identification is to develop the damage index with higher damage sensitivity. Although it is believed that higher order mode means more sensitivity to damage, what is the quantitative relationship between damage sensitivity of different orders and how to carry out multi-mode fusion lack theoretical guidance. This paper implements the comparison study of the location-related damage sensitivity for different mode shape curvatures and then proposes a structural damage index with sensitivity enhancement for beam structure. First, the damage sensitivity of the mode shape curvature of beam structures at different orders is compared in theory. It reveals that the damage sensitivity is location-dependent, and the second-order mode in the even 16.6% region is more sensitive than the third-order mode in the simply supported beam. Second, a structural damage index with sensitivity enhancement for beam structure is proposed according to the relationship between the damage sensitivity of mode shape curvature at different orders and locations. Third, a simply supported beam model and a steel stringer bridge model with multiple main girders are both investigated to illustrate the comparison results of the damage sensitivity at different orders and the advantages of the proposed structural damage index. It shows that the confused damage sensitivities are very common between different mode orders, the sensitivity-enhanced damage index that considers the damage location always shows certain degree of improvement of damage indication ability in different damage areas. Finally, the effectiveness and accessibility of the proposed method are verified by a simply supported beam experiment.
Bridge Damage Identification Based on LSTM Network and Contact Point Response
Authors: Yin Xinfeng , Yang Yuecheng , Huang Zhou , Yan Wanli
Published: January 2024

In this study, a bridge damage identification method based on the Long Short-Term Memory (LSTM) network and the contact point response is proposed, which utilizes the time behavior of the contact point response. The contact point response serving as the input to the LSTM network is obtained by calculating the vehicle-bridge interaction motion equation. A new bridge damage indicator titled the Euclidean Distance Damage Index (EDDI) is developed based on the difference between the actual and predicted values of the contact point response. Under ideal road surface conditions, the EDDI calculated in the healthy state of the bridge remains below 0.16, while exceeding 1.0 in the damaged state. When road roughness is considered, the EDDI is calculated to be less than 0.12 in the healthy state of the bridge and higher than 0.65 in the damaged state. The results show that the EDDI is more effective in distinguishing between the damaged and the healthy states of the bridge. Meanwhile, road roughness has a negative effect on the damage sensitivity of EDDI.
Global–Local Damage Diagnostic Approach for Large Civil Structures with Very Limited Sensors
Authors: Lakshmi K. , Arora Prateek , Rama Mohan Rao A.
Published: January 2024

It is important but still challenging to detect structural damage with limited instrumentation in the spatially large civil infrastructure. In this paper, a damage detection algorithm is proposed employing a global–local approach with limited sensors for detecting structural damage of spatially large civil engineering structures. The proposed algorithm is based on measuring frequency response functions (FRFs) at convenient yet selective locations on the structure with very limited sensors to localize the region of damage in the structure using the proposed global diagnostic approach. Once the local region of damage is established, local diagnostics are performed in the isolated small region of the structure using high fidelity sensing, still, a limited number of sensors in the small localized region (segment) of the structure, to precisely locate the damage. The principal component analysis combined with fractal dimension theory is employed for local diagnostics. Numerical studies have been conducted on a 6 m simply supported beam and a 30-storey framed structure idealized as a shear building. Experimental verification of the proposed global–local damage diagnostic approach is also carried out. Studies presented in this paper indicate that the global–local approach for damage diagnosis of spatially large structures is very promising for precisely locating the damage with very limited sensors.
A Dynamic Modeling Method for Soft Pneumatic Robotic Arms Considering Both Geometric Nonlinearity and Visco-Hyperelasticity
Authors: Wang Tao , Wang Xi , Fu Guoqiang , Lu Caijiang
Published: January 2024

This work proposes a new dynamic modeling approach that integrates the principle of virtual power and a spring–damper–fluid equivalent method. It is able to simultaneously consider the geometric and material nonlinearity including hyperelasticity and viscoelasticity of the soft robotic arm. Meanwhile, the nonuniform deformation of the soft arm wall can be introduced into the model based on the equivalent model. A general prototype of soft robotic arms is fabricated and validation experiments of three pneumatic actuation modes are carried out. A maximum position error of 3.64[Formula: see text]mm at the end of the soft arm is obtained with an eight-segment theoretical model for the 280[Formula: see text]mm long and 30[Formula: see text]mm thick prototype in an approximate step actuation test with a maximum pneumatic pressure of 11.5[Formula: see text]kPa. The comparisons between the theoretical prediction and experimental results demonstrate a high accuracy of the proposed modeling method. Besides, simulations of dynamic motions under in-plane and out-of-plane actuation are carried out respectively, illustrating that the proposed method has the ability to describe a variety of actuation forms. The proposed dynamic modeling method provides a new way for modeling the soft robotic arms and has guiding significance for the design and control of soft robotic arms.
Subsonic Aeroelastic Stability Analysis and Vibration Control of a Plate by Using Nonlinear Energy Sink
Authors: Qiao Yu , Yao Guo
Published: January 2024

Vibration suppression and stability control are classic issues in the field of vibration and control. The nonlinear energy sink (NES) is an effective approach for vibration reduction proposed in recent years. It has the advantages of wide frequency vibration isolation properties and without inputting excessive energy. This paper focuses on the stability and passive vibration control of a plate in subsonic airflow by applying the NES. Two kinds of NESs with linear stiffness and with cubic stiffness are proposed and their vibration control performances are compared. The kinetic equations of the plate with NES are established by using the extended Hamilton principle and analyzed by the incremental harmonic balance (IHB) method. The advantages of the hybrid stiffness NES are demonstrated by comparing with the cubic nonlinear stiffness NES. From the results, the vibration suppression effect of the hybrid stiffness NES is more significant than the purely cubic one. However, the effective vibration reduction range of the cubic stiffness NES is wider than the hybrid one. The optimal design parameters of the NES and the effect of the installation position are also discussed.
Directly Self-Starting Second-Order Explicit Integration Methods with Dissipation Control and Adjustable Bifurcation Points for Second-Order Initial Value Problems
Authors: Li Jinze , Cui Naigang , Li Hua , Lian Yiwei , Yu Kaiping , Zhao Rui
Published: January 2024

This paper proposes a directly self-starting second-order [Formula: see text]-sub-step explicit method, within which the three novel members are developed and analyzed for demonstration. The novel explicit schemes can output second-order accelerations for general structures, which cannot be achieved for the directly self-starting single- and two-sub-step algorithms. Each explicit algorithm achieves controllable algorithmic dissipation and adjustable bifurcation points. As a result, the novel explicit algorithms impose two algorithmic parameters, [Formula: see text] and [Formula: see text], to control numerical dissipation and bifurcation point, respectively. The parameter [Formula: see text], denoting the spectral radius at the bifurcation point, controls numerical dissipation, whereas the parameter [Formula: see text], denoting the bifurcation point, adjusts the amount of dissipation imposed in the low-frequency range. This paper provides users with two recommended selections of [Formula: see text]. Apart from these desirable features, each novel explicit algorithm attains the maximum stability bound, [Formula: see text] where [Formula: see text] denotes the number of sub-steps. The four- and five-sub-step algorithms perform optimization to reduce numerical low-frequency dissipation. As the number of sub-steps increases, the novel explicit algorithms can have better numerical characteristics without an increase in the computational effort. Numerical examples are simulated to validate the performance and superiority of the novel explicit algorithms.
The Influences of the Offshore Ground Motion and Site Factors on the Seismic Response of Immersed Tunnels
Authors: Wang Bowei , Hu Sicong , Song Guquan , Chen Baokui
Published: January 2024

Because the seabed is covered with deep slit soil and seawater layer, the characteristics between offshore and onshore ground motions are significantly different. Besides, compared with sea-crossing bridges and other marine structures, the seismic response of immersed tunnels buried under seabed can be influenced by the site condition more significantly. Therefore, it is necessary to study the effects of seawater depth, site condition and offshore ground motion on the seismic response of immersed tunnels. Firstly, offshore strong motion records from the K-NET are grouped with different epicentral distances, magnitudes, and stations, and the response spectra of offshore ground motions in different groups are compared. Then, a numerical simulation model with the water layer, offshore soil layer and immersed tube tunnel coupling is established. The seismic responses of the tunnel and the seabed site are compared by inputting offshore and onshore ground motions respectively. Finally, the effects of seawater depth, incidence angle, slit soft soil layer and buried depth on the seismic response of tunnel and local seabed site are systematically studied by inputting P wave and SV wave pulses respectively. The results show that the silt soft soil layer will make the horizontal seismic response of the immersed tunnel more serious under SV wave incidence. The vertical seismic responses of the immersed tunnel and seabed are suppressed by the seawater layer under P wave incidence, and the response will decrease with seawater depth increasing. Besides, the effect of the buried depth and incidence angle on the seismic response of the immersed tunnel is limited.
Interval Uncertainty Identification and Application of Strain Modes in Bridge Structures Based on Monitoring Big Data
Authors: Pan Ruiyang , Dan Danhui , Yan Xingfei
Published: January 2024

In order to solve the problem of strain modal identification under strain monitoring signals with poor vibration modal information, this paper proposes a strain mode identification method with statistical stability significance. This method removes noise, vehicle-induced effects, and temperature effects from the original dynamic strain signal, retaining only vibration-related components, and obtaining a statistically stable high quality bridge strain power spectrum, thereby identifying high quality strain mode parameters. Furthermore, in order to verify the confidence level of the strain modes obtained by this method, this paper adopts the interval estimation method to estimate the power spectrum, natural frequency, damping ratio, and modal shape after statistical processing. The credibility of strain modes has been estimated by interval estimation. The confidence interval of 95% confidence for each modal parameter is obtained, achieving the confidence-level evaluation of corresponding variable modal parameter identification. In response to practical engineering problems, this paper evaluates the actual bridge data of Tongji Road Bridge in Shanghai, and explains the abnormal phenomena that occurred in the data evaluation based on the measured diseases, verifying the practicality of this method.
A New and Effective Classification Method for Complex Time Series Based on Information Measure
Authors: Li Ang , Shang Pengjian
Published: January 2024

The growing importance of time series information measure raises questions about how to effectively cluster a large number of nonlinear complex time series data and accurately extract more hidden information from them. In this paper, a clustering measurement and classification method for complex time series, the symmetrical exponential Tsallis relative information (SETRI) measure, is proposed, which aims to address these problems. The intrinsic characteristics of different types of time series information could be validly identified by this method. The modified multidimensional scaling (MDS) method, based on the SETRI measure, has the ability to display the data in the form of graphs for intuitive exhibition and accomplish the process of dimension reduction. The introduction of weighted permutation patterns allows a higher-accuracy classification not only for the time series dissimilarity quantification, but also for avoiding dispensable errors. Besides, the feasibility of the modified MDS classification method is visually and quantitatively verified by the simulated and real-world data. Compared with other MDS methods, the proposed method has better performance, which is reflected in the validity and rationality of the clustering results, thus further verifying the feasibility of the proposed method. Therefore, the new results will be helpful to develop complex data clustering and dimensionality reduction methods.
Lie centralizing mappings on generalized matrix algebras through two-sided zero products
Authors: Argaç Nurcan
Published: January 2024

Let [Formula: see text] be a generalized matrix algebra defined by the Morita context [Formula: see text] and [Formula: see text] the center of [Formula: see text]. In this paper, under some certain conditions on [Formula: see text], we prove that if [Formula: see text] is an additive map satisfying [Formula: see text] for any [Formula: see text] with [Formula: see text], then [Formula: see text] has the form [Formula: see text] for all [Formula: see text], where [Formula: see text] and [Formula: see text] is an additive map from [Formula: see text] into [Formula: see text]. Finally as its applications, we characterize Lie centralizer maps and generalized Lie derivations on [Formula: see text]. Moreover we prove that the similar conclusions remain valid on full matrix algebras, triangular algebras, upper triangular matrix algebras.
Exceptional sequences and rooted labeled forests
Authors: Igusa Kiyoshi , Sen Emre
Published: January 2024

We give a representation-theoretic bijection between rooted labeled forests with [Formula: see text] vertices and complete exceptional sequences for the quiver of type [Formula: see text] with straight orientation. The ascending and descending vertices in the forest correspond to relatively injective and relatively projective objects in the exceptional sequence. We conclude that every object in an exceptional sequence for linearly oriented [Formula: see text] is either relatively projective or relatively injective or both. We construct a natural action of the extended braid group on rooted labeled forests and show that it agrees with the known action of the braid group on complete exceptional sequences. We also describe the action of [Formula: see text], the Garside element of the braid group, on rooted labeled forests using representation theory and show how this relates to cluster theory.
Rings with S-Noetherian spectrum
Authors: Hamed Ahmed , Kim Hwankoo
Published: January 2024

Let [Formula: see text] be a commutative ring with identity and [Formula: see text] be a multiplicative subset of [Formula: see text]. We say that [Formula: see text] has [Formula: see text]-Noetherian spectrum if for every ideal [Formula: see text] of [Formula: see text] [Formula: see text] for some [Formula: see text] and some finitely generated ideal [Formula: see text] In this paper, we study rings with [Formula: see text]-Noetherian spectrum. Among other things, we give a necessary and sufficient condition for Nagata’s idealization [Formula: see text], where [Formula: see text] is an [Formula: see text]-module, to satisfy the [Formula: see text]-Noetherian spectrum. We also investigate when the amalgamated algebra along an ideal has [Formula: see text]-Noetherian spectrum. Several examples are given to illustrate the concepts and results.
Recent Advances and Prospects of Carbon Nanotubes in Nanomedicine: A Mini Review
Authors: Hui Shalmali
Published: January 2024

Currently, the field of nanoscience and nanotechnology has potential advantages in various disciplines of science. Nanomedicine has emerged as a specific application of nanotechnology in health system. The use of nanoscale materials in nanomedicine holds a promising potential for prevention, diagnosis and treatment of several diseases. During the last three decades, carbon nanotubes (CNTs) have stimulated a significant attention worldwide due to their impressive advantages like small size and mass, high surface area-to-volume ratio, easy functionalization, superb physico-mechanical properties, and so on. CNTs have provided multifunctional platforms for biological applications such as bioimaging, biosensing, medical diagnosis, phototherapy, drug and gene delivery, tissue engineering, etc. owing to their innovative and attractive properties. This review presents a comprehensive framework of the unique advantages and up-to-date advanced biomedical applications of CNTs to date, with special emphasis on the recent progress in nanomedicine like phototherapy, drug and gene delivery, and tissue engineering. Besides the applications, an overview of CNTs along with some important methodologies of synthesis is also discussed herewith. Lastly, some major concerns to be challenged and perspectives for the future development of CNTs in the field of biomedical sector are highlighted in this paper which will help to give valuable insights into new research directions.
Measurements of Sensitivity and Figure of Merit for Noble Metals (Au, Ag, Cu) Thin Film Biosensor Based on SPR Simulation Characterizations
Authors: Ahmad Omar A. , Naif Turki Alrashid Saeed , Khalaf Mohammed K.
Published: January 2024

In this paper, we investigate the influence of varying the thickness of noble metals, namely gold (Au), silver (Ag) and copper (Cu), and the incident light wavelength on the surface plasmon resonance (SPR) properties for biosensor applications. Our analysis employs the Fresnel equations to examine the absorption characteristics of these metals when the refractive index shifts by (0.03,0.06). We explore metal layer thicknesses ranging from [Formula: see text][Formula: see text]nm and incident light wavelengths of [Formula: see text] and 600[Formula: see text]nm, with incident angles ([Formula: see text]) ranging from 0° to 90°. Utilizing simulation analysis in MATLAB, we simulate the SPR responses of these metals when deposited on BK-7 glass prisms, with air as the surrounding medium. Our calculations reveal the absorption properties of Au, Ag and Cu, as indicated by the angle of incidence ([Formula: see text]SPR). Our findings demonstrate that the highest absorption occurs with copper (Cu) at [Formula: see text] (a.u.) for [Formula: see text][Formula: see text]nm and [Formula: see text][Formula: see text]nm. When [Formula: see text] is adjusted to 600[Formula: see text]nm, gold (Au) exhibits the highest absorption (A) at 0.997 (a.u.) with a thickness of [Formula: see text][Formula: see text]nm. Additionally, we calculate sensitivity values for all three metals, with copper (Cu) yielding the highest sensitivity of 101.6 Reflected Index Units (RIU-1) for both [Formula: see text] and 600[Formula: see text]nm. Furthermore, we compute the Figure Of Merit (FOM), with silver (Ag) achieving the highest FOM of 443 at [Formula: see text][Formula: see text]nm and 451 at [Formula: see text][Formula: see text]nm. These results provide important signs about noble metals’ SPR properties in biosensing, and serve as guides for optimizing the biosensors.
Synthesis of Zinc Oxide Nanoflakes by Non-Thermal Plasma Technique and Evaluation of Anticancer Activity in Vitro
Authors: Buraihi Arkan K. , Abdalameer Nisreen Kh. , Ghadeeb Nadia Jasim.
Published: January 2024

This paper describes the synthesis of ZnO nanoparticles using air microplasma jets as the main reaction medium. Various techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV—Vis spectroscopy, were employed to confirm the characterization of the artificially synthesized ZnO nanoparticles. The absence of additional peaks associated with secondary phases of ZnO, as revealed by the XRD analysis, indicates the exceptional purity of these nanoparticles. Through the use of SEM, we examined the surface morphology and observed a substantial rate of agglomeration. The energy band gaps of ZnO nanoparticles were determined to be 3.3 electron volts (eV). The cytotoxic effects of zinc oxide nanoparticles were assessed using the methyl thiazolyl tetrazolium (MTT) assay on breast cancer cells exposed to various doses of the nanoparticles. The Acridine-Orange/Ethidium-bromide (AO/EB) dual stain was employed to assess apoptotic cells. The data indicate that ZnO NPs can induce apoptosis, suggesting their potential as an anticancer treatment in breast cancer cell lines. The presented findings indicate that nanoscale zinc oxide particles (ZnO NPs) possess significant potential for future utilization in many biological applications. An example of such an application could be the prospective substitution for chemotherapy in the management of various forms of cancer diseases.
Formation Mechanism and Morphology Observation of Chips in High-Speed Milling of Titanium Alloy
Authors: Tong Hao , Liu Changfu , Gao Jingjing , Liu Jing
Published: January 2024

The study of chip morphology during high-speed milling is crucial in determining processing quality, but the relationship between chip formation mechanisms and process parameters in titanium alloy high-speed machining has been a difficult issue. This paper investigates milling force and temperature variation, as well as chip morphology and surface quality after milling to improve workpiece surface quality and machining efficiency and provide guidance on selecting milling parameters. Factorial analysis confirms that milling speed worsens the serrated layer of chips. In addition, the experiment confirms the influence of tool rake angle on shear strain in the milling zone, the impact of rotational speed on tool wear, and the effect of tool wear on chip morphology. The results show that increasing milling speed worsens chip serration and increases tool wear.
A Bi-Objective Inventory Model for Strategic Items in a Stochastic Environment with Partial Shortage: A Base-Stock Approach
Authors: Moharramian Ali , Pasandideh Seyed Hamid Reza
Published: January 2024

This paper suggests an ordering policy for strategic items. Based on the base stock policy, we modeled a bi-objective, multi-product inventory control system with partial back-ordering. The model aims to minimize total costs and maximize the average service level, considering stochastic constraints such as storage space, maximum allowable shortage, and maximum allowable lost sales to match real-world conditions. We used three Multi-Objective Decision-Making methods, namely Individual optimization, Desirability function, and Goal attainment, to solve the problem. TOPSIS method showed the Goal attainment method’s superiority over the others. The sensitivity analysis revealed that the mean of storage space had the most significant impact on objective functions. Also, increasing the back-order percentage can reduce the system’s total costs.
Optimizing the Mechanical Properties of the Weld in the Friction Stir Welding of Aluminum and Magnesium (A365–AZ91C)
Authors: Yasavol Noushin , Bakhshi Soroush , Afshari Mahmoud , Asvadi Omid , Reza Samadi Mohammad , Afshari Hossein
Published: January 2024

The friction stir welding of A365 and AZ91C alloys was conducted in this study to assess the effect of tilt angle, linear velocity and rotating speed on the elongation, hardness and tensile strength using the response surface method. Then, the weld microstructure was investigated by SEM, TEM and EDS analysis to deeply investigate the structure of A365–AZ91C weld. It was realized that the grain size of weld joint has grown and the crack and tunnel were formed when the rotating speed improved from 1000 to 2000[Formula: see text]rpm, which produced a decline in the hardness and strength and a rise in the elongation. Moreover, an increment of linear velocity up to 60[Formula: see text]mm/min led to the refinement of the weld microstructure, which was followed by an enhancement in the strength and hardness of the weld, whereas the elongation deteriorated. In the case of tilt angle, the highest elongation and strength were detected at a tilt angle of 2∘, but the highest hardness was observed at a tilt angle of 4∘ because of the nucleation of Al3Mg2 and Al[Formula: see text]Mg[Formula: see text] intermetallics. Results of optimization exhibited that the concurrent improvement of the strength, hardness and elongation can be acquired with the tilt angle of 3∘, rotating speed of 1600[Formula: see text]rpm and linear velocity of 53[Formula: see text]mm/min.
Application of the FMECA Method for Optimizing the Reliability of the 1600T Press
Authors: Ghemari Zine , Belkhiri Salah , Bezaf Yahia , Hamach Ala , Saad Salah
Published: January 2024

Reliability optimization is a process aimed at improving the effectiveness and efficiency of maintenance activities within an organization. This optimization can concern various aspects, including failure prevention, resource management, cost reduction, and improving the operational availability of equipment. In this work, our study aims to implement a comprehensive maintenance strategy for the 1600T press at Algal[Formula: see text] company with the primary objectives of preventing breakdowns, minimizing unplanned downtime, optimizing productivity, extending the lifespan of equipment, ensuring safety, and improving the competitiveness and profitability of the company. The problem of reliability and availability of the 1600T press at the Algal[Formula: see text] company can be addressed by a systematic approach to industrial maintenance. By adopting a holistic approach to industrial maintenance, Algal[Formula: see text] company can improve the reliability and availability of its equipment, thereby reducing unplanned downtime and optimizing overall productivity. By systematically applying FMECA to the 1600T press, the optimization efforts become data-driven and focused on addressing the most critical risks. This, in turn, significantly contributes to optimizing the reliability and availability of the equipment, reducing unplanned downtime, and enhancing overall operational efficiency.
Benchmarking a neutral-atom quantum computer
Authors: Wagner N. , Poole C. , Graham T. M. , Saffman M.
Published: January 2024

In this study, we simulated the algorithmic performance of a small neutral atom quantum computer and compared its performance when operating with all-to-all versus nearest-neighbor connectivity. This comparison was made using a suite of algorithmic benchmarks developed by the Quantum Economic Development Consortium. Circuits were simulated with a noise model consistent with experimental data from [Nature 604, 457 (2022)]. We find that all-to-all connectivity improves simulated circuit fidelity by [Formula: see text]–[Formula: see text], compared to nearest-neighbor connectivity.
Complete complementarity relations for quantum correlations in neutrino oscillations with CP violation
Authors: Blasone Massimo , De Siena Silvio , Matrella Cristina
Published: January 2024

We characterize quantum correlations encoded in a three-flavor oscillating neutrino system by taking into account CP violation. By means of the complete complementarity relations (CCR), we study the trade-off of predictability, local coherence and nonlocal correlations by using relevant parameters given by neutrino oscillation experiments. Although the CCR describe very well the contributions associated to bipartite correlations, we explore the possible presence of genuine tripartite correlations, by exploiting polygamy relations. We also provide some observations about the nonlocal advantage of quantum coherence, a mazy quantum correlation characterizing the most valuable, nonlocal, portion of quantum coherence in a multi-partite system.
Quantum α-z fidelity and α-z-weighted right mean
Authors: Dinh Trung Hoa , Le Cong Trinh , Vuong Trung Dung
Published: January 2024

In this paper, we establish some variational principles for the quantum [Formula: see text]-[Formula: see text]-fidelity. Then, we use quantum [Formula: see text]-[Formula: see text]-fidelity to measure the distance between two quantum orbits. We also study several properties of the [Formula: see text]-[Formula: see text]-weighted right mean which is the unique solution of the least squares problem with respect to the [Formula: see text]-[Formula: see text]-Bures Wasserstein distance. We show that the [Formula: see text]-[Formula: see text]-weighted right mean is a multivariate Lie–Trotter mean.
Research on Reliability of Positioning Accuracy of Electromechanical Coupling Ammunition Loading Manipulator During Rotation Process
Authors: Liu Yongji , Chen Guangsong , Qian Linfang , Zhou Shijie
Published: January 2024

The loading manipulator is an important actuator in modern artillery automatic loading systems, and it is crucial to evaluate its positioning accuracy accurately and efficiently. This paper presents a reliability analysis method based on the combination of feedforward neural network (FNN) and mixed importance sampling (MIS) to study the positioning accuracy of the loading manipulator. First, the manipulator dynamic model considering the control system is established. To improve the efficiency of reliability analysis, a surrogate model based on FNN is constructed. By searching the most probable point (MPP) of each limit state equation, an MIS density function is constructed, after which important samples can be extracted to evaluate the reliability of the positioning accuracy of the manipulator. Compared with the Monte Carlo simulation (MCS) method, the proposed method enjoys higher efficiency while ensuring accuracy. The results of the example show that the gear clearance and friction coefficient have an important effect on the positioning accuracy of the loading manipulator, which should be taken into account in the machining and installation process.
Time-Variant Reliability Analysis with an Adaptive Single-Loop Kriging Combined with Directional Sampling Method
Authors: Fan Xin , Liu Yongshou , Yao Qin , Zhang Haozhi
Published: January 2024

The difficulty in calculating time-variant reliability lies in the large number of performance function calls. This paper proposes an efficient method for time-variant reliability analysis by incorporating the directional sampling method (DS). In this method, within the framework of single-loop active learning Kriging (SL–AK), the burden of fitting the Kriging surrogate model is alleviated by constructing a novel candidate sample pool. While reducing the computational burden, the accuracy of the Kriging surrogate model remains unaffected. Unlike the traditional SL–AK, the proposed method obtains the failure probability through an improved DS method. The improved DS utilizes a bisection method for root-finding, thereby circumventing the impact of interpolation coefficients on the computation results. This method of computing failure probability not only alleviates computational burden but also enhances the precision of the estimated failure probability. Furthermore, this paper introduces global sensitive analysis (GSA) into time-variant reliability analysis, thereby expanding the applicability of GSA. The accuracy and high efficiency of the proposed method are verified through three numerical examples and two engineering examples with implicit performance function.
Investigating the compatibility of exact solutions in Weyl-type f(Q,T) gravity with observational data
Authors: Koussour M. , Myrzakulova S. , Myrzakulov N.
Published: January 2024

In this study, we investigate the dynamics of the Universe during the observed late-time acceleration phase within the framework of the Weyl-type [Formula: see text] theory. Specifically, we consider a well-motivated model with the functional form [Formula: see text], where [Formula: see text] represents the scalar of non-metricity and [Formula: see text] denotes the trace of the energy–momentum tensor. In this context, the non-metricity [Formula: see text] of the space-time is established by the vector field [Formula: see text]. The parameters [Formula: see text] and [Formula: see text] govern the gravitational field and its interaction with the matter content of the Universe. By considering the case of dust matter, we obtain exact solutions for the field equations and observe that the Hubble parameter [Formula: see text] follows a power-law behavior with respect to redshift [Formula: see text]. To constrain the model parameters, we analyze various datasets including the Hubble, Pantheon datasets, and their combination. Our results indicate that the Weyl-type [Formula: see text] theory offers a viable alternative to explain the observed late-time acceleration of the Universe avoiding the use of dark energy.
Spacetime metric from quantum-gravity corrected Feynman propagators
Authors: Fernández de Córdoba P. , Isidro J. M. , Roy Rudranil
Published: January 2024

Differentiation of the scalar Feynman propagator with respect to the spacetime coordinates yields the metric on the background spacetime that the scalar particle propagates in. Now Feynman propagators can be modified in order to include quantum-gravity corrections as induced by a zero-point length [Formula: see text]. These corrections cause the length element [Formula: see text] to be replaced with [Formula: see text] within the Feynman propagator. In this paper, we compute the metrics derived from both the quantum-gravity free propagators and from their quantum-gravity corrected counterparts. We verify that the latter propagators yield the same spacetime metrics as the former, provided one measures distances greater than the quantum of length [Formula: see text]. We perform this analysis in the case of the background spacetime [Formula: see text] in the Euclidean sector.
Generating f(R,𝒢) gravity from type IV singular bouncing cosmology
Authors: Assolohou G. C. , Aïnamon C. , Akowanou C. D. , Ganiou M. G. , Houndjo M. J. S.
Published: January 2024

In this paper, we investigate in this paper the Type IV singular bouncing in the framework of [Formula: see text] theory of gravity where [Formula: see text] and [Formula: see text] mean the curvature scalar and the Gauss–Bonnet invariant, respectively. Cosmological [Formula: see text] models constrained by the slow-roll evolution is reconstructed and their explicit forms are provided near the bounce and far away from it. One obtains finally two models whose stability is numerically analyzed in this work. Our results show that the stability of the reconstructed models is very affected by their parameters. The model far from the singularity recovers stability quickly than the model near the singularity.
Carbon Quantum Dots Carrying Antibiotics for Treating Dental Implant Bacterial Infections Following Photothermal Therapy
Authors: Jiang Yong , Hua Zhengwei , Geng Qingli , Li Ning
Published: January 2024

With the continuous development of antibacterial nanotechnology, nanoparticle-mediated photothermal therapy (PTT) could treat dental implant bacterial infections. Here, a carbon quantum dots (CQDs) loading penicillin (CQDs@penicillin) was constructed as an innovative nanoplatforms to confer promising PTT and delivery of antibiotics. In this nanosystem, CQDs with distinct antibacterial application performance were utilized as an ideal nanocarrier for drug loading, evoking photothermal effects to generate heat under near-infrared (NIR) irradiation. The delivery of penicillin could induce damage to the bacterial cell wall and play a bactericidal effect during the reproduction period of bacterial cells. The antibacterial effects in vitro implied that CQDs@penicillin could significantly kill bacterial cells without severe toxicity. This study proposes a feasible therapeutic strategy for the delivery of antibiotics to dental implant bacterial infections and simultaneously the PTT effect.
Maps preserving bi-skew η-Jordan product on von Neumann algebras
Authors: Darvish Vahid , Nouri Mojtaba , Razeghi Mehran
Published: January 2024

Let [Formula: see text] and [Formula: see text] be two von Neumann algebras such that [Formula: see text] is factor. In this paper, we suppose that [Formula: see text] from [Formula: see text] onto [Formula: see text] is bijective, unital and satisfies [Formula: see text] for all [Formula: see text] where [Formula: see text] is a nonzero scalar such that [Formula: see text]. Then, [Formula: see text] is additive ∗-isomorphism.
Prime square order Cayley graph of cyclic groups
Authors: Susanti Yeni , Erfanian Ahmad
Published: January 2024

In this paper, we consider the prime square order Cayley graph of a cyclic group [Formula: see text] of order [Formula: see text], where [Formula: see text] and [Formula: see text] are two distinct prime numbers. We discuss the Eulerianity and Hamiltonicity of the graph. Moreover, we present the girth, the diameter, the independence number, the chromatic number, the clique number, and the dominating number of the graph.