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Sintering study of Ti6Al4V powders with different particle sizes and their mechanical properties

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International journal of Minerals,Metallurgy and Materials 2018年第12期25卷 1389-1401页

作者： joséLuis Cabezas-Villa joséLemus-Ruiz Didier Bouvard Omar jiménez héctor javier vergara-hernández Luis Olmos University Michoacana of San Nicolás of hidalgo IIMMMorelia 58060México University Grenoble Alpes CNRSSIMaPGrenoble 38000France University of Guadalajara Departamento de Ingeniería de ProyectosZapopan 45100México National Technological Institute of Mexico I.T.MoreliaMorelia 58120México University Michoacana of San Nicolás of hidalgo INICITMorelia 58060México

Ti6Al4V powders with three different particle size distributions(0–20, 20–45, and 45–75 μm) were used to evaluate the effect of the particle size distribution on the solid-state sintering and their mechanical properties. The sintering kinetics was determined by dilatometry at temperatures from 900 to 1260°C. The mechanical properties of the sintered samples were evaluated by microhardness and compression tests. The sintering kinetics indicated that the predominant mechanism depends on the relative density irrespective of the particle size used. The mechanical properties of the sintered samples are adversely affected by increasing pore volume fraction. The elastic Young's modulus and yield stress follow a power law function of the relative density. The fracture behavior after compression is linked to the neck size developed during sintering, exhibiting two different mechanisms of failure: interparticle neck breaking and intergranular cracking in samples with relative densities below and above of 90%, respectively. The main conclusion is that relative density is responsible for the kinetics, mechanical properties, and failure behavior of Ti6 Al4 V powders.

关键词： Ti6Al4V powders dilatometry microhardness sintering kinetics compression failure behavior

Message Verification Protocol Based on Bilinear Pairings and Elliptic Curves for Enhanced Security in Vehicular Ad hoc Networks

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Computers, Materials and Continua 2024年第1期81卷 1029-1057页

作者： Nyangaresi V.O. Ghaib A.A. jasim h.M. Abduljabbar Z.A. Ma j. Al Sibahee M.A. Aldarwish A.j.Y. Ali A.h. Neamah h.A. Department of Computer Science and Software Engineering Jaramogi Oginga Odinga University of Science and Technology Bondo 40601 Kenya Department of Applied Electronics Saveetha School of Engineering SIMATS Tamilnadu Chennai 602105 India Information Technology Department Management Technical College Southern Technical University Basrah 61004 Iraq Department of Computer Science College of Education for Pure Sciences University of Basrah Basrah 61004 Iraq College of Big Data and Internet Shenzhen Technology University Shenzhen 518118 China huazhong University of Science and Technology Shenzhen Institute Shenzhen 518000 China National Engineering Laboratory for Big Data System Computing Technology Shenzhen University Shenzhen 518060 China Computer Technology Engineering Department Iraq University College Basrah 61004 Iraq Department of Mathematics College of Education for Pure Sciences University of Basrah Basrah 61004 Iraq Institute of Mathematics University of Debrecen Debrecen H-4002 Hungary Department of Electrical Engineering and Mechatronics Faculty of Engineering University of Debrecen Debrecen 4028 Hungary

Vehicular ad hoc networks (VANETs) provide intelligent navigation and efficient route management, resulting in time savings and cost reductions in the transportation sector. however, the exchange of beacons and messages over public channels among vehicles and roadside units renders these networks vulnerable to numerous attacks and privacy violations. To address these challenges, several privacy and security preservation protocols based on blockchain and public key cryptography have been proposed recently. however, most of these schemes are limited by a long execution time and massive communication costs, which make them inefficient for on-board units (OBUs).Additionally, some of them are still susceptible tomany *** such, this study presents a novel protocol based on the fusion of elliptic curve cryptography (ECC) and bilinear pairing (BP) operations. The formal security analysis is accomplished using the Burrows-Abadi-Needham(BAN) logic, demonstrating that our scheme is verifiably secure. The proposed scheme's informal security assessment also shows that it provides salient security features, such as non-repudiation, anonymity, and unlinkability. Moreover, the scheme is shown to be resilient against attacks, such as packet replays, forgeries,message falsifications, and impersonations. Fromthe performance perspective, this protocol yields a 37.88% reduction in communication overheads and a 44.44% improvement in the supported security features. Therefore, the proposed scheme can be deployed in VANETs to provide robust security at low overheads. © 2024 The Authors. Published by Tech Science Press.

关键词： Attacks bilinear elliptic curve cryptography (ECC) privacy security vehicular ad hoc network (VANET)

Camalote Grass (Paspalum fasciculatum Willd) as a Sustainable Raw Material for the Production of Lignocellulosic Ethanol

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journal of Sustainable Bioenergy Systems 2024年第2期14卷 23-33页

作者： María Luz May-Reyes Cintya Valerio-Cárdenas Gloria Ivette Bolio-López Manuel Mateo hernández-Villegas Miguel Ángel Velázquez-Carmona Patricia De la Cruz-Burelo Research and Postgraduate Coordination Universidad Popular de la Chontalpa Crdenas Tabasco Mexico

The current trend of replacing a percentage of gasoline with ethanol has promoted the development of new processes for its production from lignocellulosic biomass. This work reports the production of ethanol from the Camalote grass (Paspalum fasciculatum Willd). The lignocellulosic biomass was subjected to acid hydrolysis at 125C and 15 psi with h2SO4 concentrations at 5%, 10%, and 20%, obtaining an average of reducing sugars (pentoses and hexoses) from the hydrolyzed juice with 12.3%, 10%, and 17% Brix, respectively. The sugars were fermented using yeast of the Saccharomyces cerevisiae at 30C for 48 hours. Finally, the ethanol was distilled at 78C, and the average yields were obtained through analysis of variance with a 95% confidence level. The values indicate that there is a significant difference (p > 0.05), the Tukey study shows that all the % v/v averages are different from each other. For h2SO4 concentration at 5% (10.33 ± 2), h2SO4 at 10% (9.33 ± 1.8), and h2SO4 at 20% (6.33 ± 2). The acidity analysis for the ethanol obtained from each treatment gave a value of 1.8 mg/L of acetic acid in all cases.

关键词： Lignocellulosic Ethanol Lignocellulosic Biomass Camalote Grass Acid hydrolysis Energy Crops

Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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journal of Magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.Xue X.j.Li j.h.Chu M.M.Li D.N.Zou L.B.Tong School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

关键词： Mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer

Porphyrins,phthalocyanines,and related covalent-organic frameworks in the photochemical and electrochemical water splitting:A review

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Particuology 2024年第7期90卷 236-265页

作者： Oxana V.Kharissova Yolanda Peña Méndez Boris I.Kharisov Aleksandr LNikolaev Edith Luévano-hipólito Lucy T.González Universidad Autónoma de Nuevo León Ave.Universidad s/nSan Nicolás de los GarzaNuevo León66455Mexico Department of Chemistry Moscow State UniversityVorobievy HillsMoscowRussia CONACYT-Universidad Autónoma de Nuevo León Facultad de Ingeniería Civil-Departamento de Ecomateriales y EnergíaCd.UniversitariaC.P.66455San Nicolás de los GarzaNLMexico Tecnologico de Monterrey Escuela de Ingeniería y CienciasMonterreyNuevo León 64890Mexico Tecnologico de Monterrey Centro del AguaMonterreyNuevo León 64890Mexico

In this review,the possibilities of photochemical and electrochemical water splitting(WS)using porphyrins,phthalocyanines,related macrocycles,and their metal complexes are *** efforts are being carried out in order to develop novel and cheap methods for water decomposition to generate inexhaustible greener energy sources(molecular hydrogen)instead of oil and *** processes of WS in heterogeneous and homogeneous media require novel photo-and electrocatalysts,in particular those on macrocycle basis.A high WS efficiency has been observed for porphyrins and phthalocyanines,showing their suitability both for hER and OER processes are available using these relative compounds for WS *** can be used in photocatalytic and electrocatalytic WS processes both in their free forms or as metal porphyrins/porphyrinates,mainly loaded on various inorganic materials,such as Au NPs,C_(3)N_(4),GaP,KTaO_(3),GaP,and so on,as part of porphyrin-containing polymers or on electrode surface as modifying coatings,being sometimes better than commercial catalysts,such as Pt/*** h2 evolution can be considerably depended on the shape of porphyrin particles;in particular,porphyrin nanowires can yield up to 20 times more h2 than its *** certain cases,both hER and OER can be driven in the same electrolyte using metal *** capacity of metal porphyrins to generate ROS(in particular,singlet oxygen 1O_(2))under ultrasonic treatment is known and can be successfully used for h_(2)O_(2) and O_(2) *** can be used in similar processes in free form or as composites with inorganic or organic counterparts,being immobilized on nanocarbons,metal oxides and salts,or simply dissolved in water acting in a homogeneous *** additional use of ultrasound can lead to better results due to the synergistic effect of the sonochemical treatment and ***-organic frameworks are also applied for WS purposes and are mainly based

关键词： Porphyrins Phthalocyanines COFs Water splitting Photocatalysis Electrocatalysis

hybrid robust fault detection and isolation of satellite reaction wheel actuators

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journal of Control and Decision 2024年第1期11卷 117-131页

作者： h.Abbasi Nozari S.j.Sadati Rostami Paolo Castaldi Silvio Simani Faculty of Electrical and Computer Engineering Babol Noshirvani University of TechnologyBabolIran Department of Electrical Electronic and Information EngineeringUniversity of BolognaCesenaItaly Department of Engineering University of FerraraFerraraItaly

In this paper,a combined robust fault detection and isolation scheme is studied for satellite system subject to actuator faults,external disturbances,and parametric *** proposed methodology incorporates a residual generation module,including a bank of filters,into an intelligent residual evaluation ***,residual filters are designed based on an improved nonlinear differential algebraic approach so that they are not affected by external *** residual evaluation module is developed based on the suggested series and parallel ***,a new ensemble classification scheme defined as blended learning integrates heterogeneous classifiers to enhance the performance.A wide range of simulations is carried out in a high-fidelity satellite simulator subject to the constant and time-varying actuator faults in the presence of disturbances,manoeuvres,uncertainties,and *** obtained results demonstrate the effectiveness of the proposed robust fault detection and isolation method compared to the traditional nonlinear differential algebraic approach.

关键词： Robust fault detection and isolation reaction wheels blended learning series and parallel fault detection and isolation forms satellite attitude control system

A detailed comparison of the composition of(RE)-Ba-Cu-O-Ag bulk superconductors

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Superconductivity 2024年第1期9卷 87-94页

作者： j.V.j.Congreve Y.Shi A.R.Dennis h.Druiff N.C.Tutt D.A.Cardwell j.h.Durrell Department of Engineering University of CambridgeCambridgeUK

The homogeneity of the microstructure and composition are critical in determining the properties of rare earthbarium‐cuprate,single grain bulk superconductors[(RE)BCO].The magnitude of the trapped magnetic field achieveable in these technologically important materials,in particular,is influenced heavily by the size and distribution of(RE)_(2)BaCuO_(x)(RE‐211)flux pinning inclusions in the bulk microstructure,whereas the size and distribution of silver agglomerates present within the bulk superconducting matrix correlate directly with improved mechanical *** careful engineering,these materials have significant potential for application in range of devices related to energy storage,medicine,electro‐magnetic machinery and microelectronic *** of(RE)BCO bulk superconductors typically involves heating a powder compact above its peritectic decomposition temperature followed by slow cooling to facilitate the growth of a single ***(RE)BCO composition has a different peritectic temperature and growth rate,which,therefore,necessitates different requirements in the heating *** fabrication temperature and growth rate,for example,may have an effect on the RE‐211 and silver distribution,which may,in turn,affect the superconducting properties of the resulting single *** this work we compare the distributions of silver and RE‐211 in the single grain microstructures of YBCOAg,GdBCO‐Ag,EuBCO‐Ag and SmBCO‐Ag bulk superconductors using optical microscopy,scanning electron microscopy and energy dispersive X‐ray *** observe that the distributions are very similar along both the a/b‐axis and c‐axis of these *** suggests that factors other than the maximum temperature used to achieve peritectic decomposition and the rate of single grain growth are particularly influential in determining the properties of the as‐processed samples in the top seeded melt growth *** observation demonstrates there is freedom to us

关键词： YBCO‐Ag GdBCO‐Ag SmBCO‐Ag EuBCO‐Ag Composition Bulk superconductor

Effects of pyrethroid and organophosphate insecticides on reared black soldier fly larvae(hermetia illucens)

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Insect Science 2024年第3期31卷 817-834页

作者： Nathan Meijer Lisa Zoet Theo de Rijk Paul Zomer Deborah Rjkers h.j.van der Fels-Klerx joop j.A.van Loon Wageningen Food Safety Research(WFSR) Part of Wageningen University and ResearchWageningenThe Netherlands Bestico B.V. Industrieweg 6Berkel en RodenrjsThe Netherlands Plant Sciences Group Laboratory of EntomologyWageningen UniversityWageningenTheNetherlands

Black soldier fly larvae(hermetia illucens)receive growing interest as a potential alternative animal feed *** insects may be exposed to insecticide residues in the rearing *** study aimed to investigate the effects of six different pyrethroid and organophosphate insecticides on this insect species'*** toxicity of two"model"substances for each of these classes(cypermethrin;pirimiphosmethyl)was quantified,with and without the synergist piperonyl butoxide(PBO).Critical effect doses corresponding to 10%yield(CED10)for cypermethrin(0.4 mg/kg)and pirimiphos-methyl(4.8 mg/kg)were *** addition of PBO to cypermethrin enhanced its relative potency with a factor *** data were compared against the relative toxicity of two analogue substances in each class(permethrin,deltamethrin;chlorpyrifosmethyl,malathion).Results suggest that exposure to concentrations complying with legal limits can cause significant reductions in *** to multiple substances at lower concentrations resulted in negative additive and synergistic *** the tested substances,deltamethrin was most toxic,causing 94%yield at 0.5 mg/*** results suggested that transfer of tested substances to the larval biomass was substance-and concentration-specific,but appeared to be correlated to reduced yields and the presence of *** of organophosphates was overall low(high transfer may result in *** is recommended that rearing companies implement lower contractual thresholds,and that policymakers consider adjusting legally allowed maximum residue levels in insect feed.

关键词： feed insects pesticides rearing substrate

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)