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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

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Annual effective dose values from^137Cs activity concentrations in soils of Manisa,Turkey

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Nuclear Science and Techniques 2018年第7期29卷 164-170页

作者： Sermin cam Kaynar Department of Physics Faculty of Sciences and ArtsManisaCelal Bayar University45140 ManisaTurkey

In this study,the activity concentrations of the fallout radionuclide ^(137(Cs in 150 soil samples collected from 13 districts of Manisa Province were determined using a gamma ray spectrometer with a Na I(Tl) *** health risks to people resulting from external exposure were evaluated by estimating the outdoor absorbed gamma dose rate and annual effective dose rate(outdoor and indoor).The activity concentration of ^(137)Cs varied from 3.6 ± 2.0 to 124.1 ± 11.0 Bq kg^(-1),with an average value of43.3 Bq kg^(-1).The average values of the outdoor absorbed gamma dose rate and annual effective dose(outdoor plus indoor) were found to be 1.3 n gy h^(-1),and 8.0 μSv y^(-1),(6.38 + 1.59 μSv y^(-1)),*** results were compared with internationally recommended values.

关键词： 137Cs 平均价值有效剂量土壤样品土耳其 gamma 放射性核种健康风险

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A novel reusable anti-COVID-19 transparent face respirator with optimized airflow

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Bio-Design and Manufacturing 2021年第1期4卷 1-9页

作者： Hussain Alenezi Muhammet Emin cam Mohan Edirisinghe Department of Mechanical Engineering University College LondonTorrington PlaceLondon WC1E 7JEUK Department of Manufacturing Engineering College of Technological StudiesPAAET13092 Kuwait CityKuwait Center for Nanotechnology and Biomaterials Application and Research Marmara University34722 IstanbulTurkey

This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric *** material requirements are reduced by 75%compared to traditional designs and allow repeated cleaning or *** probability of virus particle inhalation is reduced using novel air filtration pathways,through square-waveform design to increase filter *** enters the mask from right and left side filters,while the area in front of the mouth is *** epoxy is used for a transparent frame,allowing lip-reading,and mask edges contain a silicone seal preventing bypass of the *** mask is manufactured using silicone molds,eliminating electricity requirements making it economical and viable in developing *** fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human *** breathing cycle was represented as a transient function,and N95 filter specifications were selected as a porous *** novel design achieved 1.2×10^(−3) kg s^(−1),20%higher than human requirements,with air streamlines velocity indicating local high speed,forcing and trapping virus particles against filter walls through centrifugal forces.

关键词： COVID-19 Mask Prototype Flow Pressure Temperature

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Hard carbon derived from coconut shells,walnut shells,and corn silk biomass waste exhibiting high capacity for Na-ion batteries

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Journal of Energy Chemistry 2021年第7期30卷 207-218页

作者： Cristina Nita Biao Zhang Joseph Dentzer camélia Matei ghimbeu Universitéde Haute-Alsace Institut de Science des Matériaux de Mulhouse(IS2M)CNRS UMR 7361F-68100 MulhouseFrance Universitéde Strasbourg F-67081 StrasbourgFrance Center for Advanced Laser Technologies(CETAL) National Institute for LasersPlasma and Radiation PhysicsAtomistilor 409 bisRO-77125 MagureleRomania Department of Applied Physics The Hong Kong Polytechnic UniversityKowloonHong KongChina Réseau sur le Stockage Electrochimique de l’Energie(RS2E) CNRS FR345933 Rue Saint Leu80039 Amiens CedexFrance

In recent years,hard carbon materials have gained significant interest as anode materials for Na-ion *** waste is considered one of the most interesting,renewable,available,and cost-effective precursor to obtain hard carbon(HC);however,HC properties must be finely tuned to achieve performance comparable to those provided by Li-ion *** this work,three biomass wastes(coconut shells,walnut shells,and corn silk) were evaluated as potential precursors for HC preparation involving a pyrolysis process and subsequent acid washing to remove the inorganic *** obtained materials exhibited low and similar specific surface areas(g^(-1)), but they presented different structures and surface *** walnut shell HC possessed a lower amount of inorganic impurities and oxygen-based functional groups compared to the coconut shell and corn silk HCs,leading to higher initial coulombic efficiency(iCE).The structural organization was higher in the case of the walnut shell HC,while the corn silk HC revealed a heterogeneous structure combining both highly disordered carbon and localized graphitized *** HCs delivered high initial reversible capacities between 293 and 315 mAh g^(-1) at 50 mA g^(-1) current rate,which remained rather stable during long-term *** best capacity(293 mAh g^(-1) after 100 charge/discharge cycles) and highest capacity retention(93%) was achieved in walnut HCs in half-cells,which could be associated with its higher sp2 C content,better organized structure,and fewer *** "adsorption-insertion" Na storage mechanism is suggested based on several *** walnut HCs exhibited an attractive energy density of 279 Wh/kg when tested in full cells.

关键词： Biomass Pyrolysis Hard carbon Anode Na-ion batteries Energy storage

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Microstructure and mechanical properties of friction-stir welded St52 steel joints

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International Journal of Minerals,Metallurgy and Materials 2018年第12期25卷 1457-1464页

作者： Tevfik kucukomeroglu Semih M.Aktarer guven Ipekoglu gurel cam Department of Mechanical Engineering Karadeniz Technical UniversityTrabzon 61080Turkey Department of Automotive Technology Recep Tayyip Erdogan UniversityRize 53100Turkey Department of Mechanical Engineering Iskenderun Technical UniversityHatay 31200Turkey

The aim of this work is to investigate the mechanical properties and microstructures of friction-stir welded(FSWed) St52 structural steel joints. In this study, St52 steel plates with a thickness of 4 mm were butt-welded by friction-stir welding(FSW) using a tungsten carbide tool having a conical pin. The microstructure of the welded zone consists of equiaxed fine ferrite, grain boundary ferrite, Widmanstatten ferrite, and aggregates of ferrite + cementite. The microhardness measurements showed that the hardness of the welded zone was significantly higher than that of the base metal. The FSWed St52 joint exhibited a significant strength overmatching in the weld region and a strength performance similar to or slightly higher than that of the base plate.

关键词： friction-stir welding St52 steel microstructure mechanical properties

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Determination of ^(210)Po and ^(210)Pb depositions in lichen and soil samples collected from K?prüba??-Manisa,Turkey

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Nuclear Science and Techniques 2018年第6期29卷 92-100页

作者： Sermin cam Kaynar Umit H. Kaynar Umran Hicsonmez Omer S. Sevinc Department of Physics Faculty of Sciences and Arts Manisa Celal Bayar University 45140 Manisa Turkey Science Education Faculty of Education Manisa Celal Bayar University 45900 Manisa Turkey Department of Chemistry Faculty of Sciences and ArtsManisa Celal Bayar University 45140 Manisa Turkey Primary School Science Teaching Duzce University81620 Manisa Turkey

üIn this study, we aimed to determine the accumulations of ^(210) Po and ^(210) Pb in soil and lichen samples in K? prü bas??. The K? prü bas?? district is home to the largest uranium deposits in Turkey. To date, there has been no study recorded in the literature related to ^(210) Po and ^(210) Pb depositions in lichens in K? prü bas??. Six different lichen species(Cladonia convoluta, Parmelina tiliacea, Physcia stellaris, Pleurosticta acetabulum, Xanthoparmelia conspersa, and Xanthoria parietina) as well as soil samples were collected from seven sampling locations around K? prü bas??. Lichens were used as biomonitors for ^(210) Po and ^(210) Pb deposition. The ^(210) Po and ^(210) Pb activity concentrations were measured in all the samples by alpha spectrometry. The activity concentrations in the lichen samples ranged from 64 to 577 Bq kg^(-1) with an average of 266 Bq kg^(-1) for ^(210) Po and from 78 to 565 Bq kg^(-1) with an average of 333 Bq kg^(-1) for ^(210) Pb. The activity ratios of ^(210) Po/ ^(210) Pb ranged from 0.80 to 1.99. In the lichen species,the mean ^(210) Po activity values varied from 154 Bq kg^(-1) in Pleurosticta acetabulum to 390 Bq kg^(-1) in Xanthoparmelia conspersa. The range of the mean ^(210) Pb activity was between 153 Bq kg^(-1) in Cladonia convoluta and 378 Bq kg^(-1) in Parmelina tiliacea. In the soil samples, ^(210) Po and ^(210) Pb activity concentrations were ranged from14 to 1268 Bq kg^(-1) and from 19 to 1113 Bq kg^(-1),respectively. While the values of ^(210) Po and ^(210) Pb measured in the lichen samples are comparable with those of the literature, the results of ^(210) Po and ^(210) Pb in the soil taken from the uranium mine are higher than the results of the literature studies.

关键词：土壤样品地衣种土耳其收集样品测量 alpha 平均数 Po

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Effects of interface trap density on the electrical performance of amorphous InSnZnO thin-film transistor

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Journal of Semiconductors 2015年第2期36卷 82-86页

作者：梁永烨 Kyungsoo Jang S.Velumani cam Phu Thi Nguyen Junsin Yi National Key Laboratory for Electronic Measurement Technology North University of China College of Information and Communication Engineering Sungkyunkwan University Department of Electrical Engineering (SEES) CINVESTAV-IPN Avenida IPN 6508San Pedro Zacatenco Mexico D.F.

We reported the influence of interface trap density（Nt） on the electrical properties of amorphous InSnZnO based thin-film transistors,which were fabricated at different direct-current（DC） magnetron sputtering *** device with the smallest Nt of 5.68×10^11 cm^-2 and low resistivity of 1.21×10^-3Ω·cm exhibited a turn-on voltage（V（ON）） of-3.60 V,a sub-threshold swing（S.S） of 0.16 V/dec and an on-off ratio（I（ON）/I（OFF）） of^8 x 10^*** increasing Nt,the V（ON）,S.S and I（ON）/I（OFF） were suppressed to-9.40 V,0.24 V/dec and 2.59×10^8,*** V（TH） shift under negative gate bias stress has also been estimated to investigate the electrical stability of the *** result showed that the reduction in Nt contributes to an improvement in the electrical properties and stability.

关键词： a-ITZO TFTs low resistivity interface trap density electrical properties electrical stability

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Optimization, equilibrium, adsorption behavior and role of surface functional groups on graphene oxide-based nanocomposite towards diclofenac drug

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Journal of Environmental Sciences 2020年第7期32卷 137-150页

作者： Thuan Van Tran Duyen Thi cam Nguyen Hanh TNLe Dai-Viet NVo Sonil Nanda Trinh Duy Nguyen Nguyen Tat Thanh Hi-Tech Institute Nguyen Tat Thanh UniversityHo Chi Minh City 755414Viet Nam Center of Excellence for green Energy and Environmental Nanomaterials(CE@grEEN) Nguyen Tat Thanh UniversityHo Chi Minh City 755414Viet Nam Institute of Hygiene and Public Health Ho Chi Minh City 700000Viet Nam Department of Chemical and Biochemical Engineering University of Western OntarioLondonOntarioCanada

Aquatic contamination of diclofenac(DCF),an emergent non-steroidal anti-inflammatory drug(NSAIDs),can result in adverse effects to many ecosystems through ***,introducing effective remediation techniques to sequester the pharmaceutical wastes is highly fundamental to prevent their accumulation in the ***,adsorption has been presented as a green and efficient ***,we report the characterization and application of the novel magnetic nanocomposite(gO@CoFe2O4)derived from cobalt-based ferrite(CoFe2O4)and graphene oxide(gO)for DCF *** the optimization procedure,the response surface methodology(RSM)was adopted to investigate the impacts of DCF concentration(1.6-18.4 mg/L),DCF dosage(0.08-0.92 g/L),and solution pH(2.6-9.4)to find the optimum conditions for DCF removal,at 10.5 mg/L,0.74 g/L,and pH 4,*** the adsorption experiments,the kinetic,isotherm,thermodynamic,and intraparticle diffusion models were systematically ***,we have elucidated the role of functional groups on the surface of gO@CoFe2O4 in enhancing the adsorption of DCF *** good removal efficiency(up to 86.1%),high maximum adsorption capacity(32.4 mg/g),gO@CoFe2O4 can be a potential candidate to eliminate DCF drug from water.

关键词： Diclofenac sodium graphene oxide Magnetic nanocomposite Response surface methodology Pharmaceuticals adsorption

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Association between measles antibodies in vaccinated and naturally infected mothers with protective antibodies and the occurrence of measles in their children:A cross-sectional study in the Bavi district of Hanoi

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Asian Pacific Journal of Tropical Medicine 2019年第9期12卷 404-408页

作者： cam Nhat Nguyen Quynh Ngoc Nguyen Than Huu Dao Le Thi Quynh Mai Infectious Disease Prevention und Control Department Center for Disease ControlHonoiVietnom Virology Department National Institute of Hygiene and EpidemiologyHanoiVietnam

Objective:To determine the concentration and rate of decay of maternal Igg antibodies against measles prevalence in infants of vaccinated or naturally infected mothers and study initial measles immunization occurs in nine-month-old ***:In total,401 pregnant women and the same number of their subsequent newborns were recruited in the Bavi district of Hanoi in 2016-2017;they were divided into two groups:Older women(born before 1985,n=201)and younger women(born after 1990,n=200).Samples were collected at five time-points;week 36 of pregnancy,birth(cord),and 3,6,and 9 months after ***-specific Igg antibody levels were ***:In total,77.06% of the 401 pregnant women were seropositive for measles-specific Igg antibodies.A significantly greater proportion of mothers aged 30 and older(88.06%)and their newborn(93.53%)were seropositive compared to the mothers aged 25 and younger(66.00%),and their newborn(72.00%)(Pgnificantly higher geometric mean titres(gMT)of measles Igg antibodies than the infants of younger mothers(Pgg antibodies together with gMT decreased from 82.97%(506.96)at the age of three months to 23.19%(45.22)at the age of nine ***:This study provides a profile of maternal antibodies against measles in Vietnamese infants and investigates the early susceptibility to measles in both the infants of vaccinated mothers and mothers with naturally acquired *** data suggest that determining the appropriate age for measles vaccination is paramount for the elimination of measles in Vietnam.

关键词： Infant Measles Seropositive National Expanded Program of Immunization Vietnam

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From Concepts to Consistent Object Specifications:Translation of a Domain-Oriented Feature Framework into Practice

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Journal of Computer Science & Technology 2001年第3期16卷 208-230页

作者： Harald E. Otto CAD/cam Research, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, 113-8656 Tokyo, Japan CAD/cam Research University of Tokyo Tokyo Japan

A steady increase in consumer demands, and severe constraints from both a somewhat damaged environment and newly installed government policies, require today's product design and development to be faster and more efficient than ever before, yet utilizing even fewer resources. New holistic approaches, such as total product life cycle modeling which embraces all aspects of a product's life cycle, are current attempts to solve these problems. Within the field of product design and modeling, feature technology has proved to be one very promising solution component. Owing to the tremendous increase in information technology, to transfer from low level data processing towards knowledge modeling and information processing is about to bring a change in almost every computerized application. From this viewpoint, current problems of both feature frameworks and feature systems are analyzed in respect to static and dynamic consistency breakdowns. The analysis ranges from early stages of designing (feature) concepts to final system implementation and application. Por the first time, an integrated view is given oil approaches, solutions and practical experience, with feature concepts and structures, providing both a feature framework and its implementation with sufficient system architecture and computational power to master a fair number of known consistency breakdowns, while providing for robust contexts for feature semantics and integrated models. Within today's heavy use of information technology these are pre-requisites if the full potential of feature technology is to be successfully translated into practice.

关键词： framework integration feature semantics conceptual structures model consistency

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