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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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Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： g.Murali Division of Research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called geopolymer based ultra-highperformance concrete(gUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of gUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of gUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in gUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,gUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre geopolymer Silica fume Alkaline activators

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Nitrogen mineralization in the oldest climax communities in the eastern Mediterranean region

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Journal of Forestry Research 2024年第1期35卷 213-228页

作者： Fatma Selcen Sakar gürcan güleryüz Department of Biology Section Ecology GörükleGraduate School of Natural and Applied ScienceUniversity of Bursa Uludağ16059 NilüferBursaTurkey Department of Biology Section Ecology GörükleFaculty of Science and ArtsUniversity of Bursa Uludağ16059 NilüferBursaTurkey

In this study,we investigated how tree species affect N mineralization in connection to some soil properties and seconder metabolite levels of litter,in the soil of the old-est native forest *** the oldest pure communi-ties of Pinus nigra(PN),Fagus orientalis(FO),and Abies bornmuelleriana(AB)in the mountain range of Mount Uludağ,Bursa,Turkey,annual net yield and N mineraliza-tion in the 0-5-and 5-20-cm soil layers were determined in a field incubation study over 1 *** locations were chosen from 1300 to 1600 m a.s.l.,and moisture content(%),pH,water-holding capacity(%),organic C,total N,and C/N ratio,and annual net mineral N yield of the soil and hydro-lyzed tannic acid and total phenolic compounds in litter were compared for these forest *** had the highest annual net Nmin yield(43.9±4.8 kg ha^(-1) a^(-1)),*** the lowest(30.5±4.2 kg ha^(-1) a^(-1)).Our findings show that in the oldest forest ecosystems,the seasonal soil moisture content and tree species play an essential role in N cycling and that hydrolyzed tannic acids and total phenolic compounds effectively control N *** acid and total phenolics in the litter were found to inhibit nitrification,but total phenolics were found to stimulate ammonification.

关键词： Oldest forest communities Nitrogen mineralization Nitrification Tannic acid Total phenolic Litter

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Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

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Harmonics in the Squirrel Cage Induction Motor Analytic Calculation Part III: Influence on the Torque-speed Characteristic

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 86-102页

作者： g.Kovács the ganz Electric Works BudapestHungary

The harmonics that appear in the squirrel cage asynchronous machine have been discussed in great detail in the literature for a long time. However, the systematization of the phenomenon is still pending, so we made an attempt to fill this gap in the previous parts of our study by elaborating formulas for calculation of parasitic torques. It was a general demand among those who work in this field towards the author to verify his formulas with measurements. In the literature, it seems,only one detailed, purposeful series of measurements has been published so far, the purpose of which was to investigate the effect of the number of rotor slots on the torque-speed characteristic curve of the machine. The main goal of this study is to verify the correctness of the formulas by comparing them with the referred series of measurements. Relying on this, the expected synchronous parasitic torques were developed for the frequently used rotor slot numbers-as a design guide for the ***, together with our complete table for radial magnetic pull published in our previous work, the designer has all the principles, data and formulas available for the right number of rotor slots for his given machine and for the drive system. This brings this series of papers to an end.

关键词： Asynchronous parasitic torques Induction motor Squirrel cage rotor Space harmonics Synchronous parasitic torques

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健康领域的文化能力

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中国卫生政策研究 2016年第2期9卷 71-78页

作者： Napier A D Ancarno C Butler B Calabrese j Chater A Chatterjee H guesnet F Home R Jacyna S Jadhav S Macdonald A Neuendorf U Parkhurst A Reynolds R scambler g Shamdasani S Smith S Z Stougaard-Nielsen J Thomson L Tyler N Volkmann A M Walker T Watson J Williams AC Willott C Wilson J Woolf K 伦敦大学学院英国伦敦WC1E6BT 伦敦国王学院英国伦敦WC2R2LS 贝德福特大学英国贝德福特LV13JV 国际长寿中心英国伦敦SW1P3QB

1背景尽管人类对其他社会的兴趣纵贯历史的各个阶段，但是检验不同文化概念对人类健康实践的影响从20世纪才开始，当时是伴随着长期的人类学田野调查产生的，这些田野调查揭露了不同文化之间相关卫生实践的多样性、复杂性和连续性。

关键词：文化能力人类健康人类学多样性连续性复杂性调查

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文化与健康关系概述

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中国卫生政策研究 2016年第1期9卷 74-79页

作者： Napier AD Ancarno C Butler B Calabrese J Chater A Chatterjee H guesnet F Horne R Jacyna S Jadhav S Macdonald A Neuendorf U Parkhurst A Reynolds R scambler g Shamdasani S Smith SZ Stougaard-Nielsen J Thomson L Tyler N Volkmann AM Walker T Watson J Williams AC Willott C Wilson J Woolf K 伦敦大学学院英国伦敦WC1E6BT 伦敦国王学院英国伦敦WC2R2LS 贝德福特大学英国贝德福特LV13JV 国际长寿中心英国伦敦SW1P3QB

1引言2013年2月6日,人们聚集在威斯敏斯特教堂对面的伦敦伊丽莎白二世女王会议中心（Queen Elizabeth II Conference Centre）外面,听取中斯塔福德郡NHS信托基金会（Mid Staffordshire NHS Foundation Trust）关于2005年和2009年西米德... 详细信息

1引言2013年2月6日,人们聚集在威斯敏斯特教堂对面的伦敦伊丽莎白二世女王会议中心（Queen Elizabeth II Conference Centre）外面,听取中斯塔福德郡NHS信托基金会（Mid Staffordshire NHS Foundation Trust）关于2005年和2009年西米德兰兹郡一所NHS医院内数百名可预防性死亡的原因调查。患者家属、卫生政策决策者以及新闻界人士一起听取了调查结果,并想知道谁应该承担此次事故的责任。

关键词：健康文化调查结果 2009年 NHS 可预防性患者家属卫生政策

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Neuroimaging in atypical normal tension glaucoma:debating routine implementation in the absence of classic neurological findings

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International Journal of Ophthalmology(English edition) 2024年第3期17卷 509-517页

作者： Umay güvenç gülizar Demirok güner Üney Selma Uzman Ophthalmology Department Ankara Training and Research HospitalAnkara 06230Turkey

●AIM:To assess the necessity of neuroimaging in patients with neurological or atypical findings of normal tension glaucoma(NTg)who do not exhibit typical glaucoma manifestations.●METHODS:A retrospective analysis was conducted on 90 atypical NTg patients who underwent cranial magnetic resonance imaging(MRI)due to atypical *** demographic characteristics,clinical parameters,and radiological findings were recorded.●RESULTS:Among the patients,66.7%had abnormal radiology results,with the most common findings being gliosis(34.4%),sequelae of cerebrovascular events and vascular malformations(14.4%),and benign intracranial mass lesions(11%).Non-glaucomatous visual field defects were more frequently observed in patients with abnormal neuroimaging ***,there were no significant differences in intraocular pressure,optic disc parameters,retinal nerve fiber layer thickness,and visual field indices between patients with normal and abnormal radiological *** mean age of the patients was ***,there was a significant age difference,with the abnormal radiology group having a higher median age(P=0.021).●CONCLUSION:The study highlights the importance of cranial imaging in older NTg patients to detect underlying pathologies and prevent *** suggests that neuroimaging may be warranted in NTg patients with atypical visual field defects incompatible with ***,routine neuroimaging in all NTg patients without classic neurological signs may not be necessary.

关键词： normal tension glaucoma neuroimaging atypical visual field defects

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Combustion characteristics of low-quality lignite for different bed material sphericities in a circulating fluidized bed boiler:A numerical study

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Particuology 2024年第7期90卷 364-382页

作者： Barış gürel gülşah Karaca Dolgun Osman İpek Ali Keçebaş Department of Mechanical Engineering Engineering FacultySüleyman Demirel UniversityÇünürIspartaTurkey Department of Energy Systems Engineering Technology FacultyMuğla SıtkıKoçman UniversityKötekliMenteşeMuğlaTurkey

This study delves into the combustion behavior of various lignite types within a circulating fluidized bed boiler(CFBB),with a primary focus on the impact of different bed material sphericity ratios(0.5,0.7,and 0.9).Utilizing bed material with a sphericity ratio of 0.9 sourced from theÇan power plant and verified through experimentation,the research reveals several key ***,furnace temperatures tended to rise with higher sphericity ratios,albeit with variations between lignite types,particularly highlighting the complexity of this relationship in the case of gLI-Tunçbilek *** levels in the combustion chamber remained consistent across different sphericity ratios,indicating minimal influence on pressure *** combustion efficiency,especially at the bottom of the boiler,was observed at lower sphericity levels(0.5 and 0.7)forÇan lignite,as reflected in CO_(2) mole *** NO_(x) emissions generally decreased with lower sphericity,the sensitivity to sphericity varied by lignite type,with Ilgın lignite showcasing low NO_(x) but high SO_(2) emissions,underscoring the intricate interplay between lignite properties,sphericity,and ***,this study advances our understanding of CFBB combustion dynamics,offering insights valuable for optimizing performance and emissions control,particularly in lignite-based power.

关键词： Circulating fluidized bed boiler Computational particle fluid dynamics method Particle sphericity ratios NO_(x)and SO_(2)emissions Energy production efficiency

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文化、不平等性与卫生服务提供

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中国卫生政策研究 2016年第3期9卷 74-80,F0003页

作者： Napier A D Ancarno C Butler B Calabrese J Chater A Chatterjee H guesnet F Horne R Jacyna S Jadhav S Macdonald A Neuendorf U Parkhurst A Reynolds R scambler g Shamdasani S Smith S Z Stougaard-Nielsen J Thomson L Tyler N Volkmann A M Walker T Watson J Williams A C Willott C Wilson J Woolf K 伦敦大学学院英国伦敦WC1E6BT 伦敦国王学院英国伦敦WC2R2LS 贝德福特大学英国贝德福特LV13JV 国际长寿中心英国伦敦SW1P3QB

1动态不平等性对基层医疗卫生人力的影响政治、社会、文化、专业群体皆建立在一致且常规的人类行为之上。当遭受巨大变革和内外压力时,这些群体会变得十分脆弱。尤其在动荡时期,这些群体往往更关注社会和文化的差异性,而非二者的一致性... 详细信息

1动态不平等性对基层医疗卫生人力的影响政治、社会、文化、专业群体皆建立在一致且常规的人类行为之上。当遭受巨大变革和内外压力时,这些群体会变得十分脆弱。尤其在动荡时期,这些群体往往更关注社会和文化的差异性,而非二者的一致性。尽管社会中的个体思维和行为会呈现较大的差异,但对健康的感知具有统一性,并在更广范围人群内尤为突出,这主要归因于文化价值观的作用。广义的文化心态会随着时间和地理位置的不同而不同,就像健康的社会决定因素也会因文化类型的不同而产生差异。

关键词：卫生服务不平等性专业群体基层医疗卫生结构暴力个体思维文化类型价值观体系文化心态卫生人员

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