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Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adj.sting Y addition

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j.urnal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： j.A.Liu S.j.Liu B.Wang W.B.Sun X.j.Liu Z.W.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of Bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for Bionics-j.lin University Weihai 264205PR China

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adj.st the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),W-phase(Mg_(3)Zn_(3)Y_(2)),and LPSO phase(Mg_(12)ZnY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 Mj.m^(3)to 10.97 Mj.m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

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Concentration of Copper, Zinc, Lead, Cadmium, and Nickel in the Incinerator Bottom Ash in Five County Hospitals in Kenya

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j.urnal of Geoscience and Environment Protection 2024年第6期12卷 90-114页

作者： Muriithi j. Githinj. Paul M. Nj.gu Zipporah Nganga Mohamed Karama Institute of Tropical Medicine and Infectious Diseases (ITROMID) Jomo Kenyatta University of Agriculture and Technology (JKUAT) Nairobi Kenya Institute of Energy and Environmental Technology Jomo Kenyatta University of Agriculture and Technology (JKUAT) Nairobi Kenya Academic Research and Student Affairs South Eastern Kenya University Kitui Kenya School of Public Health Amref International University Nairobi Kenya

Healthcare wastes contain potentially harmful microorganisms, inorganic and organic compounds that pose a risk to human health and the environment. Incineration is a common method employed in healthcare waste management to reduce volume, quantity, toxicity as well as elimination of microorganisms. However, some of the substances remain unchanged during incineration and become part of bottom ash, such as heavy metals and persistent organic pollutants. Monitoring of pollution by heavy metals is important since their concentrations in the environment affect public health. The goal of this study was to determine the levels of Copper (Cu), Zinc (Zn) Lead (Pb), Cadmium (Cd) and Nickel (Ni) in the incinerator bottom ash in five selected County hospitals in Kenya. Bottom ash samples were collected over a period of six months. Sample preparation and treatment were done using standard methods. Analysis of the heavy metals were done using atomic absorption spectrophotometer, model AA-6200. One-Way Analysis of Variance (ANOVA) was performed to determine whether there were significant differences on the mean levels of Cu, Zn, Pd, Cd and Ni in incinerator bottom ash from the five sampling locations. A post-hoc Tukey’s Test (HSD) was used to determine if there were significant differences between and within samples. The significant differences were accepted at p ≤ 0.05. To standardize the results, overall mean of each metal from each site was calculated. The metal mean concentration values were compared with existing permissible levels set by the WHO. The concentrations (mg/kg) were in the range of 102.27 - 192.53 for Cu, Zn (131.68 - 2840.85), Pb (41.06 - 303.96), Cd (1.92 - 20.49) whereas Ni was (13.83 - 38.27) with a mean of 150.76 ± 77.88 for Copper, 131.66 ± 1598.95 for Zinc, 234.60 ± 262.76 for Lead, 12.256 ± 10.86 for Cadmium and 29.45 ± 18.24 for Nickel across the five sampling locations. There were significant differences between levels determined by one-way ANOVA of Zn (

关键词： Healthcare Waste Disposal Public Health Environment Incineration Heavy Metals Bottom Ash

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Fetal Head Compression: Its Possible Role in Neurologic Inj.ry

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Open j.urnal of Obstetrics and Gynecology 2024年第1期14卷 124-143页

作者： Barry S. Schifrin Brian j. Koos Wayne R. Cohen Department of Obstetrics and Gynecology The Western University of Health Sciences Pomona USA The David Geffen School of Medicine at UCLA Los Angeles USA The University of Arizona College of Medicine Tucson USA

It is widely assumed that fetal ischemic brain inj.ry during labor derives almost exclusively from severe, systemic hypoxemia with marked neonatal depression and acidemia. Severe asphyxia, however, is one of several causes of perinatal neurological inj.ry and may not be the most common;most neonates diagnosed with hypoxic-ischemic encephalopathy do not have evidence of severe asphyxia. Sepsis, direct brain trauma, and drug or toxin exposure account for some cases, while mechanical forces of labor and delivery that increase fetal intracranial pressure sufficiently to impair brain perfusion may also contribute. Because of bony compliance and mobile suture lines, the fetal skull changes shape and redistributes cerebrospinal fluid during labor according to constraints imposed by contractions, and bony and soft tissue elements of the birth canal as the head descends. These accommodations, including the increase in intracranial pressure, are adaptive and necessary for efficient descent of the head while safeguarding cerebral blood flow. Autonomic reflexes mediated through central receptors normally provide ample protection of the brain from the considerable pressure exerted on the skull. On occasion, those forces, which are transmitted intracranially, may overcome the various adaptive anatomical, cardiovascular, metabolic, and neurological mechanisms that maintain cerebral perfusion and oxygen availability, resulting in ischemic brain inj.ry. Accepting the notion of a potentially adverse impact of fetal head compression suggests that avoidance of excessive uterine activity and of relentless pushing without steady progress in descent may offer protection for the fetal brain during parturition. Excessive head compression should be considered in the differential diagnosis of ischemic encephalopathy.

关键词： Fetal Brain Inj.ry Fetal Head Compression Ischemic Encephalopathy Neonatal Encephalopathy

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Accuracy Enhancement of the Folin-Ciocalteu Method for Propolis

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American j.urnal of Analytical Chemistry 2024年第8期15卷 253-267页

作者： Rosilene S. N. Paganotti Paulo j. S. Barbeira Instituto Federal de Educao Cincia e Tecnologia de Minas GeraisCampus Formiga Formiga MG Brazil Departamento de Qumica Instituto de Cincias Exatas Universidade Federal de Minas Gerais Belo Horizonte MG Brazil

This study presents an optimization of the Folin-Ciocalteu spectrophotometric method for the determination of total phenol content. Multivariate optimization using factorial planning 22 with a central point and central composite planning was constructed to evaluate the influence of variables in the process and maximize radiation absorption with minimal radiation scattering caused by solid formation. X-ray fluorescence and X-ray diffraction spectrometry were used to evaluate the chemical composition of solids formed and nephelometric and spectrophotometric studies were also used to evaluate whether the type, origin, dilution and dry extract contents of commercial propolis extracts would significantly influence the increase in radiation scattering and absorption. The optimized methodology added several advantages, such as reduction of reagents, time analysis, and higher accuracy.

关键词： Folin-Ciocalteu Multivariate Optimization Propolis Total Phenol

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Heat and Mass Transfer for a Nanofluid Flow in Fluidized Bed Dryer in Presence of Induced Magnetic Field

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j.urnal of Applied Mathematics and Physics 2024年第4期12卷 1401-1425页

作者： Kiptum j. Purity Mathew N. Kinyanj.i Edward R. Onyango Pan African University Institute for Basic Sciences Technology and Innovation Nairobi Kenya Department of Pure and Applied Mathematics Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

This research entails the study of heat and mass transfer of nanofluid flow in a fluidized bed dryer used in tea drying processes in presence of induced magnetic field. A mathematical model describing the fluid flow in a Fluidized bed dryer was developed using the nonlinear partial differential equations. Due to their non-linearity, the equations were solved numerically by use of the finite difference method. The effects of physical flow parameters on velocity, temperature, concentration and magnetic induction profiles were studied and results were presented graphically. From the mathematical analysis, it was deduced that addition of silver nanoparticles into the fluid flow enhanced velocity and temperature profiles. This led to improved heat transfer in the fluidized bed dryer, hence amplifying the tea drying process. Furthermore, it was noted that induced magnetic field tends to decrease the fluid velocity, which results in uniform distribution of heat leading to efficient heat transfer between the tea particles and the fluid, thus improving the drying process. The research findings provide information to industries on ways to optimize thermal performance of fluidized bed dryers.

关键词： Heat Transfer Induced Magnetic Field Nanofluid Fluidized Bed Dryer

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Selection of digital fabrication technique in the construction industry--A multi-criteria decision-making approach

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 977-997页

作者： M.P.SALAIMANIMAGUDAM j.j.YAPRAKASH Department of Structural and Geotechnical Engineering School of Civil EngineeringVellore Institute of TechnologyVellore 632014India

Digital fabrication techniques,in recent decades,have provided the basis of a sustainable revolution in the construction ***,selecting the digital fabrication method in terms of manufacturability and functionality requirements is a complex *** paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the multi-criteria decision-making *** alternatives considered in the study are concrete three-dimensional(3D)printing,shotcrete,smart dynamic casting,material intrusion,mesh molding,inj.ction concrete 3D printing,and thin forming *** criteria include formwork utilization,reinforcement incorporation,geometrical complexity,material enhancement,assembly complexity,surface finish,and build *** demonstrates different multi-criteria decision-making techniques,with both subj.ctive and obj.ctive weighting *** given ranking is based on the current condition of digital fabrication in the construction *** study reveals that in the selection of digital fabrication techniques,the criteria including reinforcement incorporation,build area,and geometrical complexity play a pivotal role,collectively accounting for nearly 70% of the overall *** the evaluated techniques,concrete 3D printing emerged as the best performer,however the shotcrete and mesh molding techniques in the second and third positions.

关键词： digital fabrication multicriteria decision-making concrete 3D printing

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Reply to the note by Li Piani et al.

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Defence Technology（防务技术） 2024年第1期31卷 603-606页

作者： T.Li Piani j.Weerheij. L.j.Sluys TU Delft Stevinweg 12628 CNDelftthe Netherlands TNO PO Box 452280 AARijswijkthe Netherlands NLDA Faculty of Military Sciences1781 CADen Helderthe Netherlands

In 2017,a ballistic phenomenological model was proposed by the authors of Ref.[1] to numerically simulate the experimental depths of small caliber proj.ctiles impacting walls made of *** opportunity for a new model in the field revealed from the observation that two older models recently used by the authors of Ref.[2] shared a linear relationship between the penetration depth P and the impacting velocity v_(O).

关键词： Penetration Adobe Modeling

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Wettability,reactivity,and interface structure in Mg/Ni system

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j.urnal of Magnesium and Alloys 2024年第2期12卷 659-672页

作者： S.Terlicka N.Sobczak Ł.Maj.P.Darłak j.j.Sobczak Institute of Metallurgy and Materials Science Polish Academy of Sciences25 Reymonta Str.KrakowPoland Faculty of Foundry Engineering AGH University23 Reymonta Str.KrakowPoland

The sessile drop method was applied to the experimental investigation of the wetting and spreading behaviors of liquid Mg drops on pure Ni *** comparison,the experiments were performed in two variants:(1)using the Capillary Purification(CP)procedure,which allows the non-contact heating and squeezing of a pure oxide-free Mg drop;(2)by classical Contact Heating(CH)*** high-temperature tests were performed under isothermal conditions(CP:760℃for 30 s;CH:715℃for 300 s)using Ar+5 wt%H_(2) *** the sessile drop tests,images of the Mg/Ni couples were recorded by CCD cameras(57 fps),which were then applied to calculate the contact angles of metal/substrate *** and transmission electron microscopy analyses,both coupled with energy-dispersive X-ray spectroscopy,were used for detailed structural characterization of the solidified *** was found that an oxide-free Mg drop obtained by the CP procedure showed a wetting phenomenon on the Ni substrate(an average contact angleθ<90°in<1 s),followed by fast spreading and good wetting over the Ni substrate(θ_((CP))~20°in 5 s)to form a final contact angle ofθ_(f(CP))~18°.In contrast,a different wetting behavior was observed for the CH procedure,where the unavoidable primary oxide film on the Mg surface blocked the spreading of liquid Mg showing apparently non-wetting behavior after 300 s contact at the test ***,in both cases,the deep craters formed in the Ni substrates under the Mg drops and significant change in the structure of initially pure Mg drops to Mg-Ni alloys suggest a strong dissolution of Ni in liquid Mg and apparent values of the final contact angles measured for the Mg/Ni system.

关键词： Magnesium-based alloys Sessile drop tests Capillary purification procedure Wettability Reactivity Contact angle

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Study of the Physical and Mechanical Properties of Titanium in Volume by the MEAM Method

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Modeling and Numerical Simulation of Material Science 2024年第1期14卷 58-68页

作者： Yahnn j. Mighensle Mimboui Alain S. Dzabana Honguelet Timothée Nsongo Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo Research Group on Physical and Chemical Properties of Materials Brazzaville Congo Association Alpha Sciences Beta Technologies Brazzaville Congo Geological and Mining Research Centre Brazzaville Congo

In this work we present the results of our study on the physical and mechanical properties of titanium in volume. The work consisted in determining its physical and mechanical properties under different crystallographic structures (HCP, FCC, BCC and SC) using the Modified Embedded Atom Method (MEAM) and the MEAM potential of titanium. We used the LAMMPS calculation code, based on classical molecular dynamics, to determine the most stable structure of titanium, which is the hexagonal compact structure (HCP) with crystal parameters a = 2.952 Å and c = 4.821 Å and a cohesion energy of -4.87 eV. This structure is seconded by the cubic centred structure (BCC) with a lattice parameter a = 3.274 Å and a cohesive energy of -4.84 eV. It was shown that titanium can crystallise into a third structure which is the face-centred cubic (FCC) structure with a lattice parameter a = 4.143 Å and a cohesive energy of -4.82 eV. The results obtained in this study were compared with the theoretical results and showed considerable agreement.

关键词： MEAM Potential LAMMPS Code Molecular Dynamics Elastic Constants Modules Ovito

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The Generalized Stackelberg Equilibrium of the Two-Person Stopping Game

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j.urnal of the Operations Research Society of China 2024年第1期12卷 155-168页

作者： Marek Skarupski Krzysztof j.Szaj.wski Faculty of Pure and Applied Mathematics Wroclaw University of Science and Technology50-370WrocƚawDolonoslaskiePoland

In modeling the bilateral selection of states of the process,Dynkin(Dokl Akad Nauk USSR 185:241–288,1969)proposed a two-person game in which players use stopping moments as *** purpose of this work is to present a model of the game in which the players have different information about the process itself,as well as various laws to stop the process and accept its *** game model uses the stochastic process apparatus,in particular,the ability to create different filters for the same *** sets of stopping moments based on different filters are not identical,which allows us to model different sets of strategies for *** show that the follower,by observing the behavior of a rational leader,can recover information that is lost due to the lack of complete observation of the state of the *** the competition of two opponents for the maximum of the ***,one of whom has access to full information and the other only knows their relative ranks,we found the generalized Stackelberg *** the priority of a player observing the relative ranks is less than 50%,then that player modifies his strategy based on the behavior of the second *** a player with full information,information about the behavior of the player observing the relative ranks is useless.

关键词： No-zero-sum game Optional stopping Equilibrium Filtration

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