bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasticity Improvement in a Co-Rich Co40Fe25Cr20Ni15 High-Entropy Alloy via Al Alloying
Authors: Li Yuxiao , Chen Yu , Nutor Raymond Kwesi , Wang Nan , Cao Qingping , Wang Xiaodong , Zhang Dongxian , Jiang Jian-Zhong
Published: January 2023

The mechanical properties of high-entropy alloys (HEAs) can be regulated by altering the stacking fault energy (SFE) through compositional modulation. The Co-rich HEAs, exhibiting deformation twinning and even strain-induced martensitic transformation at room temperature, suffer from insufficient ductility at high strength. In this work, we developed Co-rich (Co40Fe25Cr20Ni15)100−xAlx (x = 0 and 5 at.%) HEAs and investigated their tensile behaviors at room temperature. The addition of Al resulted in a massive improvement in the strength-ductility product, even at similar grain sizes, and also altered the fracture mode from quasi-cleavage to ductile dimple fracture. Interestingly, both alloys were deformed by mechanical twinning, which was also verified by molecular dynamics (MD) simulations. The MD simulations revealed the SFE increased upon Al addition; however, the slip energy barrier was reduced, which favored the mobility of dislocations and twinning propensity to prolong strain hardening. The present findings provide further insights into the regulation of mechanical properties of HEAs by Al-alloying.
Burdock-Derived Composites Based on Biogenic Gold, Silver Chloride and Zinc Oxide Particles as Green Multifunctional Platforms for Biomedical Applications and Environmental Protection
Authors: Zgura Irina , Badea Nicoleta , Enculescu Monica , Maraloiu Valentin-Adrian , Ungureanu Camelia , Barbinta-Patrascu Marcela-Elisabeta
Published: January 2023

Green nanotechnology is a rapidly growing field linked to using the principles of green chemistry to design novel nanomaterials with great potential in environmental and health protection. In this work, metal and semiconducting particles (AuNPs, AgClNPs, ZnO, AuZnO, AgClZnO, and AuAgClZnO) were phytosynthesized through a “green” bottom-up approach, using burdock (Arctium lappa L.) aqueous extract. The morphological (SEM/TEM), structural (XRD, SAED), compositional (EDS), optical (UV–Vis absorption and FTIR spectroscopy), photocatalytic, and bio-properties of the prepared composites were analyzed. The particle size was determined by SEM/TEM and by DLS measurements. The phytoparticles presented high and moderate physical stability, evaluated by zeta potential measurements. The investigation of photocatalytic activity of these composites, using Rhodamine B solutions’ degradation under solar light irradiation in the presence of prepared powders, showed different degradation efficiencies. Bioevaluation of the obtained composites revealed the antioxidant and antibacterial properties. The tricomponent system AuAgClZnO showed the best antioxidant activity for capturing ROS and ABTS•+ radicals, and the best biocidal action against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The “green” developed composites can be considered potential adjuvants in biomedical (antioxidant or biocidal agents) or environmental (as antimicrobial agents and catalysts for degradation of water pollutants) applications.
Electronic Structure of NdFeCoB Oxide Magnetic Particles Studied by DFT Calculations and XPS
Authors: Samardak Vadim Yu. , Komissarov Alexander A. , Dotsenko Alexander A. , Korochentsev Vladimir V. , Osmushko Ivan S. , Belov Anton A. , Mushtuk Pavel S. , Antonov Valerii A. , Ahmadpour Ghader , Nasirpouri Farzad , Samardak Alexander S. , Ognev Alexey V.
Published: January 2023

Neodymium-iron-boron magnetic oxide powders synthesized by sol–gel Pechini method were studied by using X-ray photoelectron spectroscopy (XPS) and quantum chemical modeling. The powder structure was examined by using X-ray diffraction (XRD) and modeled by using density functional theory (DFT) approximation. The electronic structures of the core and valent regions were determined experimentally by using X-ray photoelectron spectroscopy and modeled by using quantum chemical methods. This study provides important insights into the electronic structure and chemical bonding of atoms of NdFeCoB oxide particles with the partial substitution of Fe by Co atoms.
Phosphorous- and Boron-Doped Graphene-Based Nanomaterials for Energy-Related Applications
Authors: Ubhi Manpreet Kaur , Kaur Manpreet , Grewal Jaspreet Kaur , Sharma Virender K.
Published: January 2023

Doping is a great strategy for tuning the characteristics of graphene-based nanomaterials. Phosphorous has a higher electronegativity as compared to carbon, whereas boron can induce p-type conductivity in graphene. This review provides insight into the different synthesis routes of phosphorous- and boron-doped graphene along with their applications in supercapacitors, lithium- ions batteries, and cells such as solar and fuel cells. The two major approaches for the synthesis, viz. direct and post-treatment methods, are discussed in detail. The former synthetic strategies include ball milling and chemical vapor discharge approaches, whereas self-assembly, thermal annealing, arc-discharge, wet chemical, and electrochemical erosion are representative post-treatment methods. The latter techniques keep the original graphene structure via more surface doping than substitutional doping. As a result, it is possible to preserve the features of the graphene while offering a straightforward handling technique that is more stable and controllable than direct techniques. This review also explains the latest progress in the prospective uses of graphene doped with phosphorous and boron for electronic devices, i.e., fuel and solar cells, supercapacitors, and batteries. Their novel energy-related applications will continue to be a promising area of study.
Effect of Adding Gadolinium Oxide Promoter on Nickel Catalyst over Yttrium-Zirconium Oxide Support for Dry Reforming of Methane
Authors: Alreshaidan Salwa B. , Al-Fatesh Ahmed , Lanre Mahmud S. , Alanazi Yousef M. , Ibrahim Ahmed A. , Fakeeha Anis H. , Albaqi Fahad , Anojaidi Khalid , Bagabas Abdulaziz
Published: January 2023

The dry reforming of methane (DRM) was studied for seven hours at 800 °C and 42 L/(g·h) gas hourly space velocity over Ni-based catalysts, promoted with various amounts of gadolinium oxide (x = 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 wt.%) and supported on mesoporous yttrium-zirconium oxide (YZr). The best catalyst was found to have 4.0 wt.% of gadolinium, which resulted in ∼80% and ∼86% conversions of CH4 and CO2, respectively, and a mole ratio of ∼0.90 H2/CO. The addition of Gd2O3 shifted the diffraction peaks of the support to higher angles, indicating the incorporation of the promoter into the unit cell of the YZr support. The Gd2O3 promoter improved the catalyst basicity and the interaction of NiO with support, which were reflected in the coke resistance (6.0 wt.% carbon deposit on 5Ni+4Gd/YZr; 19.0 wt.% carbon deposit on 5Ni/YZr) and the stability of our catalysts. The Gd2O3 is believed to react with carbon dioxide to form oxycarbonate species and helps to gasify the surface of the catalysts. In addition, the Gd2O3 enhanced the activation of CH4 and its conversion on the metallic nickel sites.
Serial Cultivation of an MSC-Like Cell Line with Enzyme-Free Passaging Using a Microporous Titanium Scaffold
Authors: Sakisaka Yukihiko , Ishihata Hiroshi , Maruyama Kentaro , Nemoto Eiji , Chiba Shigeki , Nagamine Masaru , Hasegawa Hiroshi , Hatsuzawa Takeshi , Yamada Satoru
Published: January 2023

In vitro studies on adherent cells require a process of passage to dissociate the cells from the culture substrate using enzymes or other chemical agents to maintain cellular activity. However, these proteolytic enzymes have a negative influence on the viability and phenotype of cells. The mesenchymal stem cell (MSC)-like cell line, C3H10T1/2, adhered, migrated, and proliferated to the same extent on newly designed microporous titanium (Ti) membrane and conventional culture dish, and spontaneous transfer to another substrate without enzymatic or chemical dissociation was achieved. The present study pierced a 10 μm-thick pure Ti sheet with 25 μm square holes at 75 μm intervals to create a dense porous structure with biomimetic topography. The pathway of machined holes allowed the cells to access both sides of the membrane frequently. In a culture with Ti membranes stacked above- and below-seeded cells, cell migration between the neighboring membranes was confirmed using the through-holes of the membrane and contact between the membranes as migration routes. Furthermore, the cells on each membrane migrated onto the conventional culture vessel. Therefore, a cell culture system with enzyme-free passaging was developed.
Preliminary Studies into Cutting of a Novel Two Component 3D-Printed Stainless Steel–Polymer Composite Material by Abrasive Water Jet
Authors: Szatkiewicz Tomasz , Perec Andrzej , Radomska-Zalas Aleksandra , Banaszek Kamil , Balasz Blazej
Published: January 2023

Composites are materials with a heterogeneous structure, composed of two or more components with different properties. The properties of composites are never the sum or average of the properties of their components. There is a lot of research and many models on the different property assessments of composite materials. Composites are used as construction materials in key areas of technology, including in civil and mechanical engineering, aviation and space technology, and others. This work presents a modern composite material created with 3D-printing technology using the SLM method, and the possibility of its processing with one of the advanced manufacturing technologies, i.e., the Abrasive Water Jet (AWJ). Tests planned using DoE methods were carried out by changing control parameters such as the pressure, abrasive flow, and traverse speed. As a dependent parameter, the surface roughness parameter Sq (squared mean height) was selected and measured in different places of the cut composite. Based on the S/N ratio, the most favorable control parameters of the cutting process were also determined to achieve the lowest roughness of the cut surface. A clear effect of the controlled cutting process on the surface roughness was observed, as well as roughness variation for the metal and polymer component. In addition, the contact surface of the polymer with the metal in the cut zone was analyzed. Analysis of the contact surfaces on the microscope showed that the gap between the polymer–metal contact surfaces does not exceed 2.5 μm.
Biofuels and Nanocatalysts: Python Boosting Visualization of Similarities
Authors: Gomes Souza Fernando , Pal Kaushik , Ampah Jeffrey Dankwa , Dantas Maria Clara , Araújo Aruzza , Maranhão Fabíola , Domingues Priscila
Published: January 2023

Among the most relevant themes of modernity, using renewable resources to produce biofuels attracts several countries’ attention, constituting a vital part of the global geopolitical chessboard since humanity’s energy needs will grow faster and faster. Fortunately, advances in personal computing associated with free and open-source software production facilitate this work of prospecting and understanding complex scenarios. Thus, for the development of this work, the keywords “biofuel” and “nanocatalyst” were delivered to the Scopus database, which returned 1071 scientific articles. The titles and abstracts of these papers were saved in Research Information Systems (RIS) format and submitted to automatic analysis via the Visualization of Similarities Method implemented in VOSviewer 1.6.18 software. Then, the data extracted from the VOSviewer were processed by software written in Python, which allowed the use of the network data generated by the Visualization of Similarities Method. Thus, it was possible to establish the relationships for the pair between the nodes of all clusters classified by Link Strength Between Items or Terms (LSBI) or by year. Indeed, other associations should arouse particular interest in the readers. However, here, the option was for a numerical criterion. However, all data are freely available, and stakeholders can infer other specific connections directly. Therefore, this innovative approach allowed inferring that the most recent pairs of terms associate the need to produce biofuels from microorganisms’ oils besides cerium oxide nanoparticles to improve the performance of fuel mixtures by reducing the emission of hydrocarbons (HC) and oxides of nitrogen (NOx).
Degradation Mechanism of a Sauce-Glazed Ware of the Song Dynasty Salvaged out of the Water at Dalian Island Wharf: Part I—The Effect of the Surface-Attached Composite Coagula
Authors: Ding Rao , Li Weidong , Yang Zelin , Xu Changsong , Lu Xiaoke
Published: January 2023

Dalian Island is located in the sea area near Pingtan County, Fujian, Southeast China. The sea area used to be the junction of the eastern and western ship routes on the Maritime Silk Road, and is also an important region for underwater archaeology in China. This study focused on a sauce-glazed ware of the Song Dynasty, with serious degradation, which was salvaged out of the water at the Dalian Island Wharf. Optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and micro-Raman spectroscopy were used to comprehensively analyze the composition, phase attributes and microstructure of the ware and the surface-attached coagula. The findings revealed that the sea wave-borne debris scoured the surface of the ware, causing mechanical damage to varying degrees and a significant decrease in its degradation resistance. This was the primary factor accounting for the poor preservation state of the salvaged ceramic ware, and the precondition for the subsequent attachment of marine organisms and the deposition of inorganic pollutants. The calcareous skeletons formed on the surface induced by the bio-mineralization of coralline algae (a type of marine plant) could resist the mechanical action caused by the motion of sea waves, thereby slowing down the ware’s degradation process. In other words, the calcareous skeletons played a ‘bio-protective’ role to a certain degree. In addition, inorganic pollutants represented by iron rusts also participated in the corrosion of the glaze. Some pollutants were directly deposited on the pits and cracks on the surface of the ware, which brought stress to the glaze and glaze/body interface, causing the glaze to further crack and spall. Moreover, iron rusts reacted with the glaze, leading to chemical alteration, accompanied by the formation of iron silicate as the alteration product. Anorthite crystals in the interlayer did not participate in the reaction but remained at the original position. The alteration product gradually replaced the original glass phase of the glaze and entered into the body via pores and cracks. In conclusion, the complex degradation morphology of the salvaged sauce-glazed ware could be attributed to the combined action of mechanical damage, marine bio-fouling, and chemical alteration.
Electrocatalytic Degradation of Rhodamine B Using Li-Doped ZnO Nanoparticles: Novel Approach
Authors: Ganesh Vanga , Ravi Kumar Bandapelli , AlAbdulaal Thekrayat. H. , Yahia Ibrahim. S. , Abdel-wahab Mohamed Sh. , Ade Ramesh , Hussien Mai S. A. , Keshway Mohamed
Published: January 2023

In this paper, we discuss the preparation of Li-doped ZnO nanostructures through combustion and report on their structural, morphological, optical, and electrocatalysis properties. X-ray diffraction analyses show that the samples have a structure crystallized into the usual hexagonal wurtzite ZnO structure according to the P63mc space group. The scanning electron microscope images conceal all samples’ nanosphere bundles and aggregates. The reflectance spectra analysis showed that the direct bandgap values varied from 3.273 eV (for pure ZnO, i.e., ZnL1) to 3.256 eV (for high Li-doped ZnO). The measured capacitance concerning frequency has estimated the variation of dielectric constant, dielectric loss, and AC conductivity against AC electric field frequency. The dielectric constant variations and AC conductivity are analyzed and discussed by well-known models such as Koop’s phenomenological theory and Jonscher’s law. The Raman spectra have been recorded and examined for the prepared samples. Rhodamine B was electro-catalytically degraded in all prepared samples, with the fastest time for ZnL5 being 3 min.
Seismic Behavior of Concrete Columns Retrofitted with a Brace-Type Replaceable Steel Link
Authors: Kim Min Sook , Lee Young Hak
Published: January 2023

This paper presents the results of a combined cyclic loading test on a single reinforced concrete column which was retrofitted with a newly proposed brace-type replaceable steel link. A total of four retrofitted reinforced concrete columns, with the length of the brace as a variable, were fabricated and tested. A companion column without retrofitting was used as the control specimen. The test results indicate that the proposed brace-type replaceable steel link can be effective in retrofitting the concrete columns, resulting in improvements in the strength, stiffness, and energy dissipation of columns. We observed that the maximum load increases by at least 87%, effective stiffness increases by 44%, and energy dissipation capacity increases by 91% when compared with non-retrofitted specimen.
Investigation of a Simple Viscoelastic Model for a PVC-Gel Actuator under Combined Mechanical and Electrical Loading
Authors: Zhang Maorong , Jakobsen Johnny , Li Ruiqin , Bai Shaoping
Published: January 2023

PVC gels are gaining more attention in the applications of soft actuators. While their characteristics have been extensively studied experimentally, precise models that predict the deformation due to imposed mechanical and electrical forces are not yet available. In this work, a viscoelastic model based on a combination of a Maxwell and a Kelvin–Voigt model is developed to describe the responsive deformation of the actuator. The model parameters are tuned using data obtained from a unique experimental setup. The PVC gel used in the actuator is made from PVC and dibutyl adipate (DBA) together with a tetrahydrofuran (THF) solvent. A full factorial test campaign with four and three levels for the mechanical and electrical forces, respectively, are considered. The results showed that some of the viscoelastic response could be captured by the model to some extent but, furthermore, the stiffness behavior of the PVC gel seemed to be load-type-dependent, meaning that the PVC-gel material changed stiffness due to the magnitude of the electrical force applied and this change was not equal to a similar change in mechanical force.
Study on the Dynamic Evolution Behavior and Failure Mechanism of Burn-Through Instability during In-Service Welding by Combining In-Situ Observation and Failure Analysis
Authors: Zhang Hongjie , Han Tao , Wang Yong
Published: January 2023

There remains a lack of systematic understanding of burn-through instability, which also restricts the development of evaluation criteria. Based on the designed test device, the dynamic evolution behavior and failure mechanism of burn-through instability were investigated by combining in-situ CCD observation and failure analysis. In the initial stage of burn-through instability, the penetrating defect initiated beneath the molten pool bulge and propagated toward the arc. Finally, the weld centerline cracks or pinholes contributed to the pipeline failure. Based on in-situ observation, the burn-through pinhole was found to be forming in the overheating zone. Cracks and pinholes were found simultaneously in the burn-through instability zone and played an essential role in the burn-through instability. It could be concluded that a major burn-through hole was mainly developed from the fusion line to the inner wall surface along the wall thickness. According to the failure behavior and phenomena, the in-service burn-through instability area was divided into four parts, which were the damage failure (DF) zone, burn-through instability (BTI) zone, propagation (P) zone, and secondary burn-through zone (BT2). The failure mechanisms of the damage failure (DF) zone and burn-through instability (BTI) zone were significantly affected by the high temperature and plastic strain. The failure behavior of the propagation (P) zone was influenced considerably by the DF and BTI zones. The secondary burn-through zone was mainly affected by the high temperature. The uneven distribution of chemical elements showed an important influence on defect initiation.
Enzymatic Transesterification of Atlantic Salmon (Salmo salar) Oil with Isoamyl Alcohol
Authors: Gumbytė Milda , Makareviciene Violeta , Sendzikiene Egle
Published: January 2023

In this experimental study, biodiesel was synthesized from the salmon oil using the Lipozyme®RM IM (Bagsværd, Denmark) as a biocatalyst. Isoamyl alcohol was used as an acyl acceptor in the transesterification process. The aim of this study is to select the best process conditions, aiming to obtain the highest transesterification degree that meets the requirements of the EN 14214 standard. Response surface methodology (RSM) was used for statistical analysis and optimization of process parameters. A four-factor experimental design was modelled by central compositional design (CCD) to investigate the effects of biocatalyst concentration, isoamyl alcohol-to-oil molar ratio, temperature, and duration on transesterification degree. It was determined that the optimal parameters for biodiesel synthesis were the following: an enzyme concentration of 11% (wt. of oil mass); a process temperature of 45 °C; a process duration of 4 h; and an alcohol-to-oil molar ratio of 6:1. The transesterification degree of biodiesel reached 87.23%. The stepwise addition of isoamyl alcohol during the transesterification process further increased the degree of transesterification to 96.5%.
Uncertain Dynamic Characteristic Analysis for Structures with Spatially Dependent Random System Parameters
Authors: Du Wenyi , Ma Juan , Zhou Changhu , Yan Yongchun , Wriggers Peter
Published: January 2023

This work presents a robust non-deterministic free vibration analysis for engineering structures with random field parameters in the frame of stochastic finite element method. For this, considering the randomness and spatial correlation of structural physical parameters, a parameter setting model based on random field theory is proposed to represent the random uncertainty of parameters, and the stochastic dynamic characteristics of different structural systems are then analyzed by incorporating the presented parameter setting model with finite element method. First, Gauss random field theory is used to describe the uncertainty of structural material parameters, the random parameters are then characterized as the standard deviation and correlation length of the random field, and the random field parameters are then discretized with the Karhunen–Loeve expansion method. Moreover, based on the discretized random parameters and finite element method, structural dynamic characteristics analysis is addressed, and the probability distribution density function of the random natural frequency is estimated based on multi-dimensional kernel density estimation method. Finally, the random field parameters of the structures are quantified by using the maximum likelihood estimation method to verify the effectiveness of the proposed method and the applicability of the constructed model. The results indicate that (1) for the perspective of maximum likelihood estimation, the parameter setting at the maximum value point is highly similar to the input parameters; (2) the random field considering more parameters reflects a more realistic structure.
New Materials and Technologies for Durability and Conservation of Building Heritage
Authors: Coppola Luigi , Bellezze Tiziano , Belli Alberto , Bianco Alessandra , Blasi Elisa , Cappello Miriam , Caputo Domenico , Chougan Mehdi , Coffetti Denny , Coppola Bartolomeo , Corinaldesi Valeria , D’Amore Alberto , Daniele Valeria , Di Maio Luciano , Di Palma Luca , Donnini Jacopo , Ferrara Giuseppe , Filippi Sara , Gastaldi Matteo , Generosi Nicola , Giosuè Chiara , Incarnato Loredana , Lamastra Francesca , Liguori Barbara , Macera Ludovico , Maqbool Qaisar , Mascolo Maria Cristina , Mavilia Letterio , Mazzoli Alida , Medici Franco , Mobili Alessandra , Montesperelli Giampiero , Pia Giorgio , Redaelli Elena , Ruello Maria Letizia , Scarfato Paola , Taglieri Giuliana , Tittarelli Francesca , Tulliani Jean-Marc , Valenza Antonino
Published: January 2023

The increase in concrete structures’ durability is a milestone to improve the sustainability of buildings and infrastructures. In order to ensure a prolonged service life, it is necessary to detect the deterioration of materials by means of monitoring systems aimed at evaluating not only the penetration of aggressive substances into concrete but also the corrosion of carbon-steel reinforcement. Therefore, proper data collection makes it possible to plan suitable restoration works which can be carried out with traditional or innovative techniques and materials. This work focuses on building heritage and it highlights the most recent findings for the conservation and restoration of reinforced concrete structures and masonry buildings.
Assessment of the Mechanical Properties of Selected PLA Filaments Used in the UAV Project
Authors: Graba Marcin , Grycz Andrzej
Published: January 2023

The paper presents the evaluation of selected mechanical properties of PLA filaments used in the production of unmanned aerial vehicles (UAV). The manuscript covers a short description of the principles of pattern design and presents a shortened division of incremental manufacturing technologies. The authors present and argue the choice of material that can be used in the UAV drone design. This material has been subjected to experimental tests in order to assess selected mechanical properties that can be successfully adapted to CAD/CAM/CAE systems in order to conduct engineering analyses. The manuscript presents a discussion on the influence of the method of specimen production on selected mechanical properties, as well as the issue of errors made when measuring selected mechanical properties. In addition to the assessment of the mechanical properties of the selected filament, the manuscript indicates how to adapt the determined material constants to the FEM calculation model and presents the effectiveness of topological optimization in engineering design, which allows to reduce the weight of the drone frame by about at least 20% compared with the value originally assumed.
Target Oil Pressure Recognition Algorithm for Oil Pressure Following Control of Electronic Assisted Brake System
Authors: Chen Lei , Yu Yunchen , Luo Jie , Xu Zhongpeng
Published: January 2023

The vehicle dynamics model has multiple degrees of freedom, with strong nonlinear characteristics, so it is difficult to quickly obtain the accurate target oil pressure of an electronically assisted brake system based on the model. This paper proposes a target oil pressure recognition algorithm based on the T-S fuzzy neural network model. Firstly, the braking conditions classification algorithm is built according to the sampled braking intention data. The data are divided into the emergency braking condition data and the general braking condition data by the braking conditions classification algorithm. Secondly, the recognition model is trained respectively by the different braking condition data sets. In the training process, the fuzzy C-means clustering algorithm is used to identify the antecedent parameters of the model, and the learning rate cosine attenuation strategy is applied to optimize the parameter learning process. Finally, a correction method of target oil pressure based on slip ratio is proposed, and the target oil pressure derived following control methods based on traditional PID and fuzzy PID are compared through experiments. The results show that the mean square error of oil pressure following control based on fuzzy PID is smaller, which proves that the proposed method is able to precisely control braking force.
Analysis of the Impact of Vibrations on a Micro-Hydraulic Valve Using a Modified Induction Algorithm
Authors: Stosiak Michał , Skačkauskas Paulius , Towarnicki Krzysztof , Deptuła Adam , Deptuła Anna Małgorzata , Prażnowski Krzysztof , Grzywacz Żaneta , Karpenko Mykola , Urbanowicz Kamil , Łapka Mariusz
Published: January 2023

This paper addresses the impact of mechanical vibrations of different frequencies on a particular type of valve. It has been shown that a neural network can be used to compress measurement data and determine the frequency range that is most important in describing the impact of mechanical vibrations on a micro-hydraulic overflow valve. Later, induction decision trees were used for the generated areas, determining key measurement points. The most important areas of dependence are determined using inductive decision trees in induction. The entropy measure is used to determine the most significant attribute. A modified induction algorithm was used for the comprehensive analyses. The analysis carried out in the paper identified the intervals in which the flow rate plays a decisive role for the entire amplitude and frequency spectrum. An analysis was performed for the 200…900 [Hz] frequency interval of the external driving force, with a harmonic step of 10 [Hz]. The analysis was performed while considering these main valve parameters: the pressure of the overflow valve opening p = 10 [MPa]; flow rate in the valve: 0.6, 0.8 and 1 [dm3/min]; stiffness of valve spring c = 7.49 [N/mm]. Plots were presented and for each plot, the most important four intervals were determined. They are hierarchically ordered in the interval range of the whole frequency spectrum range: (coefficient IV)—the most important; (coefficient III)—important; (coefficient II)—less important; (coefficient I)—least important. A test rig and the results of a study on the effect of mechanical vibration on changes in the amplitude-frequency spectrum of pressure pulsations of a micro-hydraulic system, in which a micro-hydraulic relief valve was subjected to mechanical vibration, are presented.
Magnetic Transition State Searching: Beyond the Static Ion Approximation
Authors: Lawrence Robert A. , Donaldson Scott J. , Probert Matt I. J.
Published: January 2023

The effect of structural relaxations on the magnetocrystalline anisotropy energy (MAE) was investigated by using density functional theory (DFT). The theory of the impact of magnetostructural coupling on the MAE was discussed, including the effects on attempt frequency. The MAE for ferromagnetic FePt (3.45 meV/formula unit) and antiferromagnetic PtMn (0.41 meV/formula unit) were calculated within the local density approximation (LDA). The effects of the structural relaxation were calculated and found to give a <0.5% reduction to the MAE for the ferromagnet and ∼20% for the antiferromagnet.
Magnetization Dynamics in FexCo1-x in Presence of Chemical Disorder
Authors: Sadhukhan Banasree , Chimata Raghuveer , Sanyal Biplab , Mookerjee Abhijit
Published: January 2023

In this paper, we present a theoretical formulation of magnetization dynamics in disordered binary alloys, based on the Kubo linear response theory, interfaced with a seamless combination of three approaches: density functional-based tight-binding linear muffin-tin orbitals, generalized recursion and augmented space formalism. We applied this method to study the magnetization dynamics in chemically disordered FexCo1−x (x = 0.2, 0.5, 0.8) alloys. We found that the magnon energies decreased with an increase in Co concentration. Significant magnon softening was observed in Fe20Co80 at the Brillouin zone boundary. Magnon–electron scattering increased with increasing Co content, which in turn modified the hybridization between the Fe and Co atoms. This reduced the exchange energy between the atoms and softened down the magnon energy. The lowest magnon lifetime was found in Fe50Co50, where disorder was at a maximum. This clearly indicated that the damping of magnon energies in FexCo1−x was governed by hybridization between Fe and Co, whereas the magnon lifetime was controlled by disorder configuration. Our atomistic spin dynamics simulations show reasonable agreement with our theoretical approach in magnon dispersion for different alloy compositions.
Effect of Bismuth on the Structure, Magnetic and Photocatalytic Characteristics of GdFeO3
Authors: Ma Yudie , Shen Hui , Fang Yating , Geng Heyan , Zhao Yu , Li Yasheng , Xu Jiayue , Ma Yunfeng
Published: January 2023

In this paper, a series of Gd1-xBixFeO3 (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) nanoparticles have been readily synthesized by a green and facile sol–gel method. It gradually changed from the orthorhombic structure (space group Pbnm) to the rhombohedral perovskite structure (space group R3c). Weak ferromagnetic behavior was effectively induced by Bi3+, with reduced magnetization. It was closely related with the lattice distortion of the perovskite structure and modified interactions between Fe-O-Fe. Boosted photocatalytic activities of Gd1-xBixFeO3 were observed for the removal of methylene blue (MB) under the visible light irradiation. In particular, Gd0.5Bi0.5FeO3 showed the optimum photocatalytic efficiency, in which the degradation efficiency reached 82.1% after 180 min of visible light illumination, with good stability and repeatability. The improved performance was mainly ascribed to enhanced visible light absorption, decreased optical band gap from 2.21 to 1.8eV and stronger charge transfer efficiency. A possible photocatalytic mechanism is also proposed according to the band structure. The results indicate that this system will be a promising candidate for the degradation of organic pollutant as a novel magnetically recoverable photocatalyst.
Computational Analysis of the Fractional Riccati Differential Equation with Prabhakar-type Memory
Authors: Singh Jagdev , Gupta Arpita , Kumar Devendra
Published: January 2023

The key objective of the current work is to examine the behavior of the nonlinear fractional Riccati differential equation associated with the Caputo–Prabhakar derivative. An efficient computational scheme, that is, a mixture of homotopy analysis technique and sumudu transform, is used to solve the nonlinear fractional Riccati differential equation. The convergence and uniqueness analysis for the solution of the implemented technique is shown. In addition, the numerical consequences are demonstrated in the form of graphical representations to verify the reliability of the applied method in obtaining the solution to the mathematical model with Prabhakar-type memory.
Periodic Behavioral Routine Discovery Based on Implicit Spatial Correlations for Smart Home
Authors: Lo Chun-Chih , Hsu Kuo-Hsuan , Chen Shen-Chien , Shieh Chin-Shiuh , Horng Mong-Fong
Published: January 2023

As the degree of elders’ social activity and self-care ability depreciates, the potential risk for elderly people who live independently increases. The development of assistive services such as smart homes could likely provide them with a safer living environment. These systems collect sensor data to monitor residents’ daily activities and provide assistance services accordingly. In order to do so, a smart home must understand its residents’ daily activities and identify their periodic behavioral daily routine accordingly. However, existing solutions mainly focus on the temporal feature of daily activities and require prior labeling of where sensors are geographically deployed. In this study, we extract implicit spatial information from hidden correlations between sensors deployed in the environment and present a concept of virtual locations that establishes an abstract spatial representation of the physical living space so that prior labeling of the actual location of the sensors is not required. To demonstrate the viability of this concept, an unsupervised periodic behavioral routine discovery method that does not require any predefined location-specific sensor data for a smart home environment is proposed. The experimental results show that with the help of virtual location, the proposed method achieves high accuracy in activity discovery and significantly reduces the computation time required to complete the task relative to a system without virtual location. Furthermore, the result of simulated anomaly detection also shows that the periodic behavioral routine discovery system is more tolerant to differences in the way routines are performed.
Survey of Cross-Modal Person Re-Identification from a Mathematical Perspective
Authors: Liu Minghui , Zhang Yafei , Li Huafeng
Published: January 2023

Person re-identification (Re-ID) aims to retrieve a particular pedestrian’s identification from a surveillance system consisting of non-overlapping cameras. In recent years, researchers have begun to focus on open-world person Re-ID tasks based on non-ideal situations. One of the most representative of these is cross-modal person Re-ID, which aims to match probe data with target data from different modalities. According to the modalities of probe and target data, we divided cross-modal person Re-ID into visible–infrared, visible–depth, visible–sketch, and visible–text person Re-ID. In cross-modal person Re-ID, the most challenging problem is the modal gap. According to the different methods of narrowing the modal gap, we classified the existing works into picture-based style conversion methods, feature-based modality-invariant embedding mapping methods, and modality-unrelated auxiliary information mining methods. In addition, by generalizing the aforementioned works, we find that although deep-learning-based models perform well, the black-box-like learning process makes these models less interpretable and generalized. Therefore, we attempted to interpret different cross-modal person Re-ID models from a mathematical perspective. Through the above work, we attempt to compensate for the lack of mathematical interpretation of models in previous person Re-ID reviews and hope that our work will bring new inspiration to researchers.
Are State-Owned Enterprises Really Ineffective? An Empirical Study Based on Stochastic Frontier Analysis
Authors: Liu Chao , Lu Jiaye , Li Ding , Jia Mengyao , Han Kunru
Published: January 2023

Technical efficiency (TE) and total factor productivity (TFP) are important criteria to ensure the enhancement of the quality and efficiency of state-owned enterprises (SOEs) and function as important indicators to assess the quality of their accomplishments. The purpose of this study is to explore whether the efficiency of SOEs is higher or lower than that of private enterprises. Transcendental logarithmic production function and stochastic frontier analysis (SFA) are used to assess the TE and TFP of listed central SOEs, local SOEs, and private enterprises, the data of which were taken from 2006–2020. The results show that the sampled private enterprises had the highest average TE during the study period, followed by the central and local SOEs. The private enterprises also had the highest average TFP growth rate, followed by the local and central SOEs. The TFP decompositions show that the TE change (TEC) and technical change (TC) indices of the SOEs were lower than those of the private enterprises. The TC, TEC, and scale change (SC) are limiting the TFP growth rates of the SOEs in labor-intensive industries. The SC of the SOEs has changed less than that of private enterprises in the sampled capital-intensive industries. Northern and southern China had the highest rates of TE and TFP growth. Indeed, this paper measures and decomposes TFP, and analyzes the efficiency of SOEs and private enterprises in different industries and regions in an international context.
Strategy Analysis for Retailer-Leading Supply Chain under Buyback Contract with Focus Theory of Choice
Authors: Zhu Xide , Hu Zhiheng , Lin Guihua , Xu Weina
Published: January 2023

This paper investigates a retailer-leading two-tier supply chain with a buyback contract under market demand uncertainty, where the retailer first announces a potential maximal order quantity and the supplier then provides a unit wholesale price to influence the retailer’s order quantity. In recent years, an increasing number of experimental studies have reported that even in repeated multi-turn games, the decisions of suppliers viewed as newsvendors deviate significantly from the expectation-maximizing options. In light of this observation, we employ the focus theory of choice to characterize suppliers’ behavioral tendencies and theoretically derive optimal unit wholesale prices based on suppliers’ focus preferences. With these results, we further explore how suppliers’ foci may influence the interactions between the retailer and the supplier. We find that when the supplier takes the positive evaluation system as the decision criterion, optimism degree and confidence level have a negative effect on the wholesale price and a positive effect on the final order quantity, and the final order quantity must be located between the most possible market demand and the upper limit of the market demand. This paper provides a behavioral perspective to analyze suppliers’ optimal responses and their influences on retailers’ decision-making. Theoretical and numerical analyses gain managerial insights for retailers to make decisions when faced with suppliers with different focus preferences.
New Fixed Point Results in Orthogonal B-Metric Spaces with Related Applications
Authors: Gnanaprakasam Arul Joseph , Mani Gunaseelan , Ege Ozgur , Aloqaily Ahmad , Mlaiki Nabil
Published: January 2023

In this article, we present the concept of orthogonal α-almost Istra˘tescu contraction of types D and D* and prove some fixed point theorems on orthogonal b-metric spaces. We also provide an illustrative example to support our theorems. As an application, we establish the existence and uniqueness of the solution of the fractional differential equation and the solution of the integral equation using Elzaki transform.
Classical and Fixed Point Approach to the Stability Analysis of a Bilateral Symmetric Additive Functional Equation in Fuzzy and Random Normed Spaces
Authors: Agilan P. , Almazah Mohammed M. A. , Julietraja K. , Alsinai Ammar
Published: January 2023

In this article, a new kind of bilateral symmetric additive type functional equation is introduced. One of the interesting characteristics of the equation is the fact that it is ideal for investigating the Ulam–Hyers stabilities in two prominent normed spaces, namely fuzzy and random normed spaces simultaneously. This article analyzes the proposed equation in both spaces. The solution of this equation exhibits the property of symmetry, that is, the left of the object becomes the right of the image, and vice versa. Additionally, the stability results of this functional equation are determined in fuzzy and random normed spaces using direct and fixed point methods.
New Results on Finite-Time Synchronization Control of Chaotic Memristor-Based Inertial Neural Networks with Time-Varying Delays
Authors: Wang Jun , Tian Yongqiang , Hua Lanfeng , Shi Kaibo , Zhong Shouming , Wen Shiping
Published: January 2023

In this work, we are concerned with the finite-time synchronization (FTS) control issue of the drive and response delayed memristor-based inertial neural networks (MINNs). Firstly, a novel finite-time stability lemma is developed, which is different from the existing finite-time stability criteria and extends the previous results. Secondly, by constructing an appropriate Lyapunov function, designing effective delay-dependent feedback controllers and combining the finite-time control theory with a new non-reduced order method (NROD), several novel theoretical criteria to ensure the FTS for the studied MINNs are provided. In addition, the obtained theoretical results are established in a more general framework than the previous works and widen the application scope. Lastly, we illustrate the practicality and validity of the theoretical results via some numerical examples.
Global Dynamics of an HTLV-I and SARS-CoV-2 Co-Infection Model with Diffusion
Authors: Elaiw Ahmed M. , Shflot Abdulsalam S. , Hobiny Aatef D. , Aly Shaban A.
Published: January 2023

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel respiratory virus that causes coronavirus disease 2019 (COVID-19). Symptoms of COVID-19 range from mild to severe illness. It was observed that disease progression in COVID-19 patients depends on their immune response, especially in elderly patients whose immune system suppression may put them at increased risk of infection. Human T-cell lymphotropic virus type-I (HTLV-I) attacks the CD4+ T cells (T cells) of the immune system and leads to immune dysfunction. Co-infection with HTLV-I and SARS-CoV-2 has been reported in recent studies. Modeling HTLV-I and SARS-CoV-2 co-infection can be a helpful tool to understand the in-host co-dynamics of these viruses. The aim of this study was to construct a model that characterizes the in-host dynamics of HTLV-I and SARS-CoV-2 co-infection. By considering the mobility of the viruses and cells, the model is represented by a system of partial differential equations (PDEs). The system contains two independent variables, time t and position x, and seven dependent variables for representing the densities of healthy epithelial cells (ECs), latent SARS-CoV-2-infected ECs, active SARS-CoV-2-infected ECs, SARS-CoV-2, healthy T cells, latent HTLV-I-infected T cells and active HTLV-I-infected T cells. We first studied the fundamental properties of the solutions of the system, then deduced all steady states and proved their global properties. We examined the global stability of the steady states by constructing appropriate Lyapunov functions. The analytical results were illustrated by performing numerical simulations. We discussed the effect of HTLV-I infection on COVID-19 progression. The results suggest that patients with HTLV-I have a weakened immune response; consequently, their risk of COVID-19 infection may be increased.
Single Earthquake Bond Pricing Framework with Double Trigger Parameters Based on Multi Regional Seismic Information
Authors: Anggraeni Wulan , Supian Sudradjat , Sukono  , Halim Nurfadhlina Abdul
Published: January 2023

The investor interest in multi-regional earthquake bonds may drop because high-risk locations are less appealing to investors than low-risk ones. Furthermore, a single parameter (earthquake magnitude) cannot accurately express the severity due to an earthquake. Therefore, the aim of this research is to propose valuing a framework for single earthquake bonds (SEB) using a double parameter trigger type, namely magnitude and depth of earthquakes, based on zone division according to seismic information. The zone division stage is divided into two stages. The first stage is to divide the covered area based on regional administrative boundaries and clustering based on the earthquake disaster risk index (EDRI), and the second stage involves clustering based on magnitude and depth of earthquakes and distance between earthquake events using the K-Means and K-Medoids algorithms. The distribution of double parameter triggers is modeled using the Archimedean copula. The result obtained is that the price of SEB based on the clustering result of EDRI categories and K-Means is higher than the price obtained by clustering EDRI categories and K-Medoids with maturities of less than 5 years. The result of this research is expected to assist the Special Purpose Vehicle in determining the price of SEB.