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Agro-Industrial Waste as a Source of Raw Material:Eggshell and Ash of Agave salmiana Useful for the Synthesis of Hydroxyapatite

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Journal of Renewable Materials 2022年第12期10卷 3559-3572页

作者： Nora Elizondo-Villarreal Luz HVerástegui-Dominguez Jose JQuijano-Briones Francisco JVázquez-Rodríguez Eden Rodríguez-Castellanos Enrique López-Cuellar Ernesto Torres-Lopez victor MCastaño-Meneses Universidad Autónoma de Nuevo León Facultad de Ciencias Fisico MatemáticasCiudad UniversitariaSan Nicolás de los GarzaNuevo LeónMéxico Universidad Autónoma de Nuevo León Facultad de ArquitecturaCiudad UniversiariaSan Nicolás de los GarzaNuevo LeónMéxico Universidad Autónoma de Nuevo León Facultad de Ingeniería Mecainicay EléctricaCiudad UniversitariaSan Nicolás de los GarzaNuevo LeónMéxico Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autonoma de MéxicoQuerétaroMéxico

Agave salmiana ash and poultry eggshell powder as Cao sources were used for obtaining nanostructured hydro-xyapatite(HAP).The synthesis was carried out by the Green Chemistry Hydrothermal Biosynthesis at 180℃ with a pH of 5,by reacting Cao from Agave Salmiana ash and Eggshell powder,with dibasic caldium phosphate(CaH-Po_(4)+2H_(2)o)in an aqueous solution,with Aloe barbadensis *** product was characterized by X-ray dif-fraction,Fourier transform infrared spectroscopy(FT-IR),Scanning Electron Microscopy(SEM),and Transmission Electron Microscopy(TEM).The size and shape of the hydroxyapatite particles changed dramati-cally in the presence of Aloe *** crystals of Hydroxyapatite were observed when Eggshell powder and Agave salmiana ash were used as raw materials in the presence of the Aloe barbadensis *** with shapes of ribbons and plates from 1 micrometers to 8 micrometers were observed when using the eggshell powder in the presence of Aloe bar badensis and,in the case of Agave salmiana ash in the presence of Aloe bar-badensis,crystals with shapes of quadra ngular prisms and hexagonal(polyhedra)with sizes from 2 micrometers to 20 micrometers were *** was therefore successfully biosynthesized by a green and sus-tainable method that reduces the environmental impact.

关键词： Hydroxyapatite raw materials Agave salmiana eggshell Aloe barbadensis surfactant

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The effect of carbon nanotubes and polypropylene fibers on bond of reinforcing bars in strain resilient cementitious composites

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Frontiers of Structural and Civil Engineering 2016年第2期10卷 214-223页

作者： Souzana P. TASTANI Maria S. KoNSTA-GDoUToS, Stavroula J. PANTAZoPoULoU victor BALoPoULoS Department of Civil Engineering Democritus University oJ Thrace Vas. Sofias Street #12 Xanthi 67100 Greece

Stress transfer between reinforcing bars and concrete is engaged through rib translation relative to concrete, and comprises longitudinal bond stresses and radial pressure. The radial pressure is equilibrated by hoop tension undertaken by the concrete cover. owing to concrete＇s poor tensile properties in terms of strength and deformability, the equilibrium is instantly released upon radial cracking of the cover along the anchorage with commensurate abrupt loss of the bond strength. Any improvement of the matrix tensile properties is expected to favorably affect bond in terms of strength, resilience to pullout slip, residual resistance and controlled *** aim of this paper is to investigate the local bond of steel bars developed in adverse tensile stress conditions in the concrete cover. In the tests, the matrix comprises a novel, strain resilient cementitious composite （SRCC） reinforced with polypropylene fibers （PP） with the synergistic action of carbon nano-tubes （CNT）. Local bond is developed over a short anchorage length occurring in the constant moment region of a four-point bending short beam. Parameters of investigation were the material structure （comprising a basic control mix, reinforced with CNTs and/or PP fibers） and the age of testing. Accompanying tests used to characterize the cementitious material were also conducted. The test results illustrate that all the benefits gained due to the synergy between PP fibers and CNTs in the matrix, namely the maintenance of the multi-cracking effect with time, the increased strength and deformability as well as the highly increased material toughness, were imparted in the recorded bond response. The local bond response curves thus obtained were marked by a resilient appearance exhibiting sustained strength up to large levels of controlled bar-slip; the elasto-plastic bond response envelope was a result of the confining synergistic effect of CNTs and the PP fibers, and it occurred even without bar yielding.

关键词： carbon nanotubes strain resilient cementitious composite polypropylene fibers tensile bending bond

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Analysis of the Effect of Subgroup Size on the X-bar Control Chart Using Forensic Science Laboratory Sample Influx Data

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Engineering（科研） 2017年第5期9卷 434-456页

作者： Samwel victor Manyele Department of Forensic Science and DNA Services Government Chemist Laboratory Authority (GCLA) Dar es Salaam Tanzania

This paper analyzes the effect of subgroup size on the x-bar chart characteristics using sample influx (SIF) into forensic science laboratory (FSL). The characteristics studied include changes in out-or-control points (oCP), upper control limit UCLx, and zonal demarcations. Multi-rules were used to identify the number of out-of-control-points, Nocp as violations using five control chart rules applied separately. A sensitivity analysis on the Nocp was applied for subgroup size, k, and number of sigma above the mean value to determine the upper control limit, UCLx. A computer code was implemented using a FoRTRAN code to create x-bar control-charts and capture oCP and other control-chart characteristics with increasing k from 2 to 25. For each value of k, a complete series of average values, Q(p), of specific length, Nsg, was created from which statistical analysis was conducted and compared to the original SIF data, S(t). The variation of number of out-of-control points or violations, Nocp, for different control-charts rules with increasing k was determined to follow a decaying exponential function, Nocp = Ae–α, for which, the goodness of fit was established, and the R2 value approached unity for Rule #4 and #5 only. The goodness of fit was established to be the new criteria for rational subgroup-size range, for Rules #5 and #4 only, which involve a count of 6 consecutive points decreasing and 8 consecutive points above the selected control limit (σ/3 above the grand mean), respectively. Using this criterion, the rational subgroup range was established to be 4 ≤ k ≤ 20 for the two x-bar control chart rules.

关键词： Forensic Science Laboratory Sample Influx Statistical Analysis X-bar Control Chart Sub-Group Size Control Chart Rules Multi-Rules for X-bar Chart out-of-Control Points

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Strain-Rate Dependency of a Unidirectional Filament Wound Composite under Compression

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Computer Modeling in Engineering & Sciences 2023年第12期137卷 2149-2161页

作者： Stepan Konev victor A.Eremeyev Hamid M.Sedighi Leonid Igumnov Anatoly Bragov Aleksandr Konstantinov Ayaulym Kuanyshova Ivan Sergeichev Skolkovo Institute of Science and Technologies Center for Materials TechnologiesMoscowRussia National Research Lobachevsky State University of Nizhny Novgorod Nizhny NovgorodRussia Dipartimento di Ingegneria Civile Ambientale e Architettura(DICAAR)Universitàdegli Studi di CagliariCagliari(CA)Italy Mechanical Engineering Department Faculty of EngineeringShahid Chamran University of AhvazAhvazIran Drilling Center of Excellence and Research Center Shahid Chamran University of AhvazAhvazIran

This article presents the results of experimental studies concerning the dynamic deformation and failure of a unidirectional carbon fiber reinforced plastic(T700/LY113)under *** test samples were manufactured through the filament winding of flat *** establish the strain rate dependencies of the strength and elastic modulus of the material,dynamic tests were carried out using a drop tower,the Split Hopkinson Pressure bar method,and standard static *** samples were loaded both along and perpendicular to the direction of the reinforcing *** applicability of the obtained samples for static and dynamic tests was confirmed through finite elementmodeling and the high-speed imaging of the deformation and failure of samples during *** a result of the conducted experimental studies,static and dynamic stress-strain curves,time dependencies of deformation and the stress and strain rates of the samples during compression were *** on these results,the strain rate dependencies of the strength and elasticity modulus in the strain rate range of 0.001-6001/s are *** is shown that the strain rate significantly affects the strength and deformation characteristics of the unidirectional carbon fiber composites under *** increase in the strain rate by 5 orders of magnitude increased the strength and elastic modulus along the fiber direction by 42%and 50%,*** loading resulted in a strength and elastic modulus increase by 58%and 50%,*** average strength along the fibers at the largest studied strain rate was about *** obtained results can be used to design structural elements made of polymer composite materials operating under dynamic shock loads,as well as to build models of mechanical behavior and failure criteria of such materials,taking into account the strain rate effects.

关键词： High strain rate composites filament winding dynamic strength Split Hopkinson Pressure bar compression

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Jokes & Cartoon

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英语沙龙（初级版） 2010年第4期 55-55页

作者： victor

A guy comes in to a bar and orders a double whiskey. He drinks it andlooks in his *** he orders another one, drinks it and looks in hispocket *** is repeated a dozen times before the bartender asks him what he *** rep... 详细信息

关键词：英语翻译方法译文课外阅读

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