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Effect of rare earth elements and their oxides on tribo-mechanical performance of laser claddings:A review

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Journal of Rare Earths 2016年第6期34卷 549-564页

作者： m.m.Quazi m.A.Fazal A.S.m.A.haseeb Farazila yusof h.h.masjuki A.Arslan Department of mechanical Engineering Faculty of EngineeringUniversity of Malaya50603 Kuala LumpurMalaysia Center for Energy Science Uni-versity of Malaya50603 Kuala LumpurMalaysia Centre of Advanced manufacturing and material Processing(AmmP Centre) University of Malaya50603 Kuala LumpurMalaysia

Laser cladding is a promising photon-based surface engineering technique broadly utilized for fabricating harder and wear resistant composite coatings. In spite of excellent properties, the practical applications of laser claddings are relatively restricted when compared with well-established coating techniques because of their inherent defects identified as cracks, pores and inclusions. Substantial evidence suggests that the incorporation of an appropriate amount of rare earth in laser claddings can remarkably prevent these defects. Additionally, the presence of rare earth in laser claddings can notably enhance tribo-mechanical properties such as surface hardness, modulus of elasticity, fracture toughness, friction coefficient and wear rate. In this literature review, the effect of rare earth in reducing dilution and cracks susceptibility of laser claddings in addition to microstructural refinement attained was examined. mechanical and tribological properties of these claddings along with their underlying mechanism were discussed in detail. Finally, this article summarizes current applications of laser claddings based on rare earth and was concluded with future research directions.

关键词： laser cladding rare earth elements microstructure tribo-mechanical properties

malaria prevalence in north-eastern Nigeria:A cross-sectional study houben Ch^(1*),Fleischmann h^2,Gǜckel m^3

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Asian Pacific Journal of Tropical medicine 2013年第11期6卷 865-868页

作者： houben Ch Fleischmann h Gckel m Diagnostic Center mmm group & Specialist hospital Yola Hospital RoadP.M.B.2266YolaAdamawa.StateNigeria medical mission Institute Tropical MedicineHermann Schell Str 797074 WrzburgGermany helios Kliniken Schwerin Wismarsche Str 393-39719049 SchwerinGermany

Objective:To assess the prevalence of malaria parasitemia in north-east Nigeria and to evaluate the measures for the prevention of ***:A village in north-eastern Nigeria was selected for the cross sectional study at the height of the rainy season in October 2011.A total of 550 inhabitants of a hamlet were recruited for this *** obtaining the consent individuals received a structured interview and were tested for malaria parasites in their blood *** testing positive for malaria were given a course of artemesinin-based combination therapy（ACT）.Results:A total of 497 inhabitants representing approximately 90 percent of the population participated:a quarter of the study group carried malaria parasitesexclusively Plasmodium falciparum（***）-representing a *** parasite rate（PfPR） of 24.5%.Besides,53/138 in the age group of 2 to hildren tested positive for *** representing a PfPR2-10 value of 38.4%.malaria control measures were used in just under a third（157/497） of this *** these measures 28/157（17.8%） still tested positive for ***:The malaria burden is overestimated for this region in north-east *** findings support an intermediate pattern of malaria *** 30%bed nets coverage for malaria control is well below the WhO estimates for 2011.

关键词： malaria control malaria endemicity malaria prevalence malaria transmission

manufacturing Process Selection of “Green” Oil Palm Natural Fiber Reinforced Polyurethane Composites Using hybrid TEA Criteria Requirement and AhP method for Automotive Crash Box

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Journal of Renewable materials 2020年第6期8卷 647-660页

作者： N.S.B.yusof S.m.Sapuan m.T.h.Sultan m.Jawaid Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)Universiti Putra MalaysiaSelangorMalaysia Faculty of Information Sciences and Engineering management Science&University SelangorMalaysia Advanced Engineering materials and Composites Research Centre Department of mechanical and manufacturing Engineering Universiti Putra MalaysiaSelangorMalaysia Department of Aerospace Engineering Faculty of EngineeringUniversiti Putra MalaysiaSelangorMalaysia

In this study,the best manufacturing process will be selected to build an automotive crash box using green oil palm natural fibre-reinforced polyurethane composite *** paper introduces an approach consist of technical aspects(T),the economic point of view(E)and availability(A),and it’s also called as TEA *** approach was developed with the goal of assisting the design engineer in the selection of the best manufacturing process during the design phase at the criteria selection *** this study,the TEA requirement will integrate with the analytical hierarchy process(AhP)to assist decision makers or manufacturing engineers in determining the most appropriate manufacturing process to be employed in the manufacture of a composite automotive crash box(ACB)at the early stage of the product development *** is obvious that a major challenge in the manufacturing selection process is lack of information regarding manufacturing of ACB using natural fibre composite(NFC).There have been no previous studies that examined ranking manufacturability processes in terms of their ***,the TEA-AhP hybrid method was introduced to provide unprejudiced criteria-ranking selection prior to evaluation of pairwise *** the end of this study,the pulforming process was selected as the best manufacturing process for fabrication of the ACB structural component.

关键词： manufacturing process selection automotive crash box natural fibre composites TEA requirement

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer m.Colón-mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose m.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis h.Pagan Rivera Jorge D.miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National Institutes of health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of Neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

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)

Conceptual design of oil palm fibre reinforced polymer hybrid composite automotive crash box using integrated approach

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Journal of Central South University 2020年第1期27卷 64-75页

作者： N S B yusof S m SAPUAN m T h SULTAN m JAWAID Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)Universiti Putra Malaysia43400 UPM SerdangSelangorMalaysia Faculty of Information Sciences and Engineering Management and Science UniversitySeksyen 1340100 Shah AlamSelangorMalaysia Advanced Engineering materials and Composites Research Centre Department of Mechanical and Manufacturing EngineeringUniversiti Putra Malaysia43400 UPM SerdangSelangorMalaysia Department of Aerospace Engineering Universiti Putra Malaysia43400 UPM SerdangSelangorMalaysia

A hybrid conceptual design approach was introduced in this study to develop a conceptual design of oil palm polymer composite automotive crash box(ACB). A combination of theory of inventive problem solving(TRIZ), morphological charts and biomimetics was applied where the foremost requirements in terms of the material characteristics, function specifications, force identification, root cause analysis, geometry profile and design selection criteria were considered. The strategy was to use creations of nature to inspire five innovative conceptual designs of the ACB structure and the AhP method was applied to perform the pairwise analysis of selecting the best ACB conceptual design. A new conceptual design for a composite ACB was conceived bearing in mind the properties of natural fibre, unlike those of conventional materials such as steel alloys and aluminium alloys. The design with the highest ranking(26.6 %) was chosen as the final conceptual design, which was the one with a honeycomb structure for the outermost profile, reinforced with a spider web structure inside the part, supported by fibre foam structure extracted from the woodpecker sponge tissue at the centre to maximize the energy absorption capability. The new design could solve the problem of bending collapse which is a major cause of failure to absorb maximum impact energy for ACB during collision. however, the final conceptual design will still need several modifications for production and assembly purposes, which will be completed in a further study.

关键词： conceptual design automotive crash box hybrid method concept selection method

h-m Bearing Capacity of A modified Suction Caisson Determined by Using Load-/Displacement-Controlled methods

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China Ocean Engineering 2016年第6期30卷 926-941页

作者：张雨坤高玉峰李大勇 Ali h.mahfouz Key Laboratory of ministry of Education for Geomechanies and Embankment Engineering Hohai UniversityNanjing 210098China College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Faculty of Petroleum and mining Engineering Suez UniversityIsmailiaEgypt

This paper presents a series of monotonically combined lateral loading tests to investigate the bearing capacity of the mSCs （modified suction caissons） in the saturated marine fine sand. The lateral loads were applied under load- and displacement-controlled methods at the loading eccentricity ratios of 1.5, 2.0 and 2.5. Results show that, in the displacement-controlled test, the deflection-softening behavior of load-deflection curves for mSCs was observed, and the softening degree of the load-deflection response increased with the increasing external skirt length or the decreasing loading eccentricity. It was also found that the rotation center of the mSC at failure determined by the load-controlled method is slightly lower than that by the displacement-controlled method. The calculated mSC capacity based on the rotation center position in serviceability limit state is relatively conservative, compared with the calculated capacity based on the rotation center position in the ultimate limit state. In the limit state, the passive earth pressures opposite the loading direction under load- and displacement-controlled methods decrease by 46% and 74% corresponding to peak values, respectively; however, the passive earth pressures in the loading direction at failure only decrease by approximately 3% and 7%, compared with their peak values.

关键词： mSC (modified suction caisson) saturated marine fine sand model tests load- and displacement-controlled loading laterally combined bearing capacity earth pressure

Analytical model for thermal lensing and spherical aberration in diode side-pumped Nd:YAG laser rod having Gaussian pump profile

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Chinese Physics B 2015年第12期24卷 334-341页

作者： m h moghtader Dindarlu m Kavosh Tehrani h Saghafifar A maleki Institute of Optics and Laser Malek-Ashtar University of Technology

In this paper, according to the temperature and strain distribution obtained by considering the Gaussian pump profile and dependence of physical properties on temperature, we derive an analytical model for refractive index variations of the diode side-pumped Nd：YAG laser rod. Then we evaluate this model by numerical solution and our maximum relative errors are 5% and 10% for variations caused by thermo–optical and thermo–mechanical effects; respectively. Finally, we present an analytical model for calculating the focal length of the thermal lens and spherical aberration. This model is evaluated by experimental results.

关键词： side-pumped laser rod Gaussian pump profile thermal effects thermal lens spherical aberration

microstructure evolution of a recycled Al-Fe-Si-Cu alloy processed by tube channel pressing

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International Journal of minerals,metallurgy and materials 2018年第10期25卷 1166-1172页

作者： m.h.Farshidi m.Rifai h.miyamoto Department of materials Science and metallurgical Engineering Ferdowsi University of Mashhad Department of mechanical Engineering Doshisha University

Although excellent recyclability is one of the advantages of Al alloys, a recycling process can reduce different properties of these alloys by adding coarse AlFeSi particles into the alloys' microstructures. One of the well-known methods for modifying the microstructure of metallic materials is the imposition of severe plastic deformation(SPD). Nevertheless, the microstructure evolutions of recycled Al alloys containing extraordinary fractions of AlFeSi particles during SPD processing have seldom been considered. The aim of the present work is to study the microstructure evolution of a recycled Al–Fe–Si–Cu alloy during SPD processing. For this purpose, tubular specimens of the mentioned alloy were subjected to different numbers of passes of a recently developed SPD process called tube channel pressing(TCP); their microstructures were then studied using different techniques. The results show that coarse AlFeSi particles are fragmented into finer particles after processing by TCP. however, decomposition and dissolution of AlFeSi particles through TCP processing are negligible. In addition, TCP processing results in an increase in hardness of the alloy, which is attributed to the refinement of grains, to an increase of the dislocation density, and to the fragmentation of AlFeSi particles.

关键词： AlFeSi intermetallic particle severe plastic deformation microstructure tube channel pressing