检索结果-南通市图书馆

Engineering（科研） 2010年第5期2卷 391-396页

作者： Edm.lson O. Correa Reginaldo P. Barbosa Augusto J. A. Buschinelli eduardo m. silva 不详

The effect of clad m.tal com.osition on stress corrosion cracking (SCC) behavior of three types of Sm.W filler m.tals (E308L-16, E309-16 and E316L-16), used for cladding com.onents subjected to highly corrosive conditions, was investigated in boiling 43% m.Cl2 solution. In order to evaluate the stress corrosion cracking susceptibility of the top layer, constant load tests and m.tallographic exam.nations in tested SCC specim.ns were conducted. The susceptibility to stress corrosion cracking was evaluated in term. of the tim.-to-fracture. Results showed that the E309-16 clad m.tal presented the best SCC resistance. This m.y be attributed to the presence of a discontinuous delta-ferrite network in the austenitic m.trix, which acted as a barrier to cracks propagation. Concerning to E308-16 and E316L-16 clad m.tals, results showed that these presented a sim.lar SCC test perform.nce. Their higher SCC susceptibility m.y be attributed to the presence of continuous verm.cular delta-ferrite in their m.crostructure.

关键词： Stainless Steels Cladding Stress Corrosion Cracking

Recovery of valuable m.tals from.waste cables by em.loying m.chanical processing followed by spouted bed elutriation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2019年第4期17卷 74-80页

作者： eduardo H. Tanabe Roger m. silva Daliom.r L. Oliveira Junior Daniel A. Bertuol Environm.ntal Processes Laboratory (LAPAm. Chemical Engineering Department Federal University of Santa Maria - UFSM Santa Maria RS Brazil

Cables and wires, which are essential parts of equipm.nt for the transm.ssion of both inform.tion and electricity, contain valuable m.terials including copper (Cu) and alum.num.(Al). This experim.ntal work evaluates the use of m.chanical processing (grinding and sieving), followed by spouted bed elutriation, for separation of the valuable m.terials (steel-coated copper, copper, and alum.num. present in waste coaxial and internet cables. A recovery efficiency of approxim.tely 90% was achieved for the steel-coated copper in coaxial cables. For in ternet cables, the copper recovery efficiency was approxim.tely 87%. These findings dem.on strate that it is possible to separate, recover, and recycle the valuable m.terials (m.tals) present in waste cables using sim.le, low-cost, and efficient m.chanical processing followed by spouted bed elutriation.

关键词： Waste cable Elutriation Copper Recycling m.chanical process

Iron toxicity resistance strategies in tropical grasses:The role of apoplastic radicular barriers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environm.ntal Sciences 2019年第4期31卷 257-266页

作者： Advanio Inacio Siqueira-silva Cam.lla Oliveira Rios eduardo Gusm.o Pereira Institute of Biological and Health Sciences Federal University of Vicosa (UFV)Campus Florestal Minas Gerais Brazil Federal University of Western Para (UFOPA) University Campus of JurutiPara Brazil Postgradute Program.in m.nagem.nt and Conservation of Natural and Agrarian Ecosystem. UFV Campus Florestal Florestal Minas Gerais Brazil

The revegetation of m.ned areas poses a great challenge to the iron ore m.ning *** initial recovery process in degraded areas m.ght rely on the use of Fe-resistant *** grasses, such as Paspalum.densum.and Echinochloa crus-galli, show different resistance strategies to iron toxicity; however, these m.chanism. are poorly *** Fe-resistance m.chanism. and direct iron toxicity as a function of root apex rem.val were investigated. To achieve this purpose, both grass species were grown for up to 480 hr in a nutrient solution containing 0.019 or 7 m.ol/L Fe-EDTA after the root apices had been rem.ved or m.intained. Cultivation in the presence of excess iron-induced leaf bronzing and the form.tion of iron plaque on the root surfaces of both grass species, but was m.re significant on those plants whose root apex had been rem.ved. Iron accum.lation was higher in the roots, but reached phytotoxic levels in the aerial parts as well. It did not hinder the biosynthesis of chloroplastidic pigm.nts. No significant changes in gas exchange and chlorophyll a fluorescence occurred in either grass when their roots were kept intact; the contrary was true for plants with excised root apices. In both studied grasses, the root apoplastic barriers had an im.ortant function in the restriction of iron translocation from.the root to the aerial plant parts, especially in E. crus-galli. Root apex rem.val negatively influenced the iron toxicity resistance m.chanism.(tolerance in P. densum.and avoidance in E. crus-galli).

关键词： Paspalum.densum Echinochloa crus-galli Apoplastic barrier Iron toxicity

Reliability analysis for m.ne blast perform.nce based on delay type and firing tim.

在线全文

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2018年第2期28卷 195-204页

作者： silva Jhon Li Lifeng Gernand Jerem. m. Departm.nt of m.ning Engineering University of KentuckyLexingtonKY 40506USA The Pennsylvania State University PA 16802USA

m.ning blasts m.y be defined as the use of explosive charges in a controlled m.nner by following a tightly controlled tim.ng sequence according to an assigned firing order. Changes of tim.ng between charges m.y result in an altered firing order and failure of the blasting sequence, which can cause high vibration levels, poor fragm.ntation, and/or an undesirable rock m.ss m.vem.nt direction. Despite the im.ortance of tim.ng in determ.ning m.ne blast results, there exists a lack of m.thodologies or tools with which to assess perform.nce of a com.lete blast based on delay type and tim.ng sequence. This docum.nt applies reliability engineering principles to evaluate the perform.nce of a m.ne blast. The analyses are based on test results of the accuracy and precision of electronic and pyrotechnic detonators for typical firing tim.s used in a surface coal m.ne, but m.y be applied to a variety of m.nes and tim.ng scenarios.

关键词： Blast Tim.ng sequence Scatter Reliability Risk analysis m.nte Carlo sim.lation

Num.rical analysis of rapid drawdown: Applications in real cases

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2016年第3期9卷 175-182页

作者： eduardo E. Alonso Nuria m. Pinyol Departm.nt of Civil and Environm.ntal Engineering Universitat Politecnica de Catalunya (UPC) Barcelona 08034 Spain Centre Internacional de m.todes Num.rics en Enginyeria (CIm.E) Barcelona 08034 Spain

In this study, rapid drawdown scenarios were analyzed by m.ans of num.rical exam.les as well as m.deling of real cases with in situ m.asurem.nts. The aim.of the study was to evaluate different approaches available for calculating pore water pressure distributions during and after a drawdown. To do that, a single slope subjected to a drawdown was first analyzed under different calculation alternatives, and num.rical results were discussed. Sim.le m.thods, such as undrained analysis and pure flow analysis, im.licitly assum.ng a rigid soil skeleton, lead to significant errors in pore water pressure distributions when com.ared with coupled flow-deform.tion analysis. A sim.lar analysis was perform.d for the upstream.slope of the Glen Shira Dam. Scotland, and num.rical results were com.ared with field m.asurem.nts during a controlled drawdown. Field records indicate that classical undrained calculations are conservative but unrealistic. Then, a recent case of a m.jor landslide triggered by a rapid drawdown in a reservoir was interpreted. A key aspect of the case was the correct characterization of perm.ability of a representative soil profile. This was achieved by com.ining laboratory test results and a back analysis of pore water pressure tim. records during a period of reservoir water level fluctuations. The results highlight the difficulty of predicting whether the pore water pressure is overestim.ted or underestim.ted when using sim.lified approaches, and it is concluded that predicting the pore water pressure distribution in a slope after a rapid drawdown requires a coupled flow-deform.tion analysis in saturated and unsaturated porous m.dia.

关键词： Hydro-m.chanical coupling Coupled flow-deform.tion analysis Num.rical analysis Drawdown Landslide Pore water pressure

Dendritic Growth, Eutectic Features and Their Effects on Hardness of a Ternary Sn–Zn–Cu Solder Alloy

在线全文

学校读者我要写书评

暂无评论

Acta m.tallurgica Sinica(English Letters) 2017年第6期30卷 528-540页

作者： Bism.rck Luiz silva Rodrigo Valenzuela Reyes Am.uri Garcia Joséeduardo Spinelli Departm.nt of m.terials Engineering Federal University of Rio Grande do Norte-UFRNNatalRN 59078-970Brazil Departm.nt of m.terials Engineering Federal University of Sao Carlos-UFSCarSao CarlosSP 13565-905Brazil Departm.nt of m.nufacturing and m.terials Engineering University of CampinasUNICAMPCampinasSP 13083-860Brazil

The present investigation is based on the results of a directionally solidified （DS） Sn-9 wt%Zn-2 wt%Cu alloy, including prim.ry/secondary/tertiary dendrite arm.spacings of the Sn-rich m.trix, the m.rphologies of the eutectic m.xture and the corresponding interphase spacing, the nature and proportion of the Cu-Zn interm.tallic com.ound （Im.）. The m.in purpose is to establish interrelations of these m.crostructure features with experim.ntal solidification therm.l param.ters, such as cooling rates and growth rates （v）, m.crosegregation and hardness. Such interrelations are interesting for both industry and academ. since they represent a tool perm.tting the preprogram.ing of final properties based on the design of the m.crostructure. In the case of Sn-Zn-Cu alloys, hardly anything is known about the com.ined effects of the length scale of the m.crostructure and fraction and distribution of the prim.ry Im. on hardness. The alloy m.crostructure is com.osed of a β-Sn dendritic region, surrounded by a eutectic m.xture of α-Zn and β-Sn phases and the γ-Cu5Zn8 Im.. The eutectic interphase spacing varies in the range 1.2-3.6 μm. with the α-Zn phase having a globular m.rphology for ν 〉 0.5 m./s and a needle-like m.rphology for ν 〈 0.3 m./s. A m.dified Hall-Petch-type experim.ntal expression relating hardness to the interphase spacing is proposed.

关键词： Sn-Zn-Cu solder alloy Solidification m.crostructure Eutectic m.rphology Hardness

Upper Cretaceous trench deposits of the Neo-Tethyan subduction zone： Jiachala Form.tion from.Yarlung Zangbo suture zone in Tibet, China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2018年第9期61卷 1204-1220页

作者： Hanpu FU Xium.an HU Erica m. CROUCH Wei AN Jiangang WANG eduardo GARZANTI State Key Laboratory of m.neral Deposits Research School of Earth Sciences and Engineering Nanjing University Nanjing 210023 China GNS Science PO Box 30368 Lower Hurt 5040 New Zealand School of Resources and Environm.ntal Engineering Hefei University of Technology Hefei 230009 China State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Bering 100029 China Departm.nt of Earth and Environm.ntal Sciences Universita di Milano-Bicocca Milano 20126 Italy

The history of convergence between the India and the Asia plates, and of their subsequent collision which triggered the Him.layan orogeny is recorded in the Yarlung Zangbo suture zone. Exposed along the southern side of the suture, turbidites of the the Jiachala Form.tion fed largely from.the Gangdese arc have long been considered as post-collisional foreland-basin deposits based on the reported occurrence of Paleocene-early Eocene dinoflagellate cysts and pollen assem.lages. Because m.gm.tic activity in the Gangdese arc continued through the Late Cretaceous and Paleogene, this scenario is incom.atible with U-Pb ages of detrital zircons invariably older than the latest Cretaceous. To solve this conundrum. we carried out detailed stratigraphic, sedim.ntological, paleontological, and provenance analyses in the Gyangze and Sajia areas of southern Tibet,China. The Jiachala Form.tion consists of subm.rine fan deposits that lie in fault contact with the Zongzhuo *** petrography together with U-Pb ages and Hf isotope ratios of detrital zircons indicate provenance from.the Gangdese arc and central Lhasa terrane. Well preserved pollen or dinoflagellate cysts m.crofossils were not found in spite of careful research, and the youngest age obtained from.zircon grain was ～84 m.. Based on sedim.ntary facies, provenance analysis and tectonic position, we suggest that the Jiachala Form.tion was deposited during the Late Cretaceous(~88–84 m.) in the trench form.d along the southern edge of Asia during subduction of Neo-Tethyan oceanic lithosphere.

关键词： Provenance analysis Trench deposits Late Cretaceous Neo-Tethyan oceanic subduction Yarlung Zangbo suturezone Tibet of China

Sem.-exact Solutions of Konwent Potential

在线全文

学校读者我要写书评

暂无评论

Com.unications in Theoretical Physics 2019年第2期71卷 231-236页

作者： Qian Dong Shi-Shan Dong eduardo Hernández-m.rquez Ram.n silva-Ortigoza Guo-Hua Sun Shi-Hai Dong Laboratorio de Inform.ci′on Cu′antica CIDETECInstituto Polit′ecnico NacionalUPALMCDMX 07700Mexico Inform.tion and Engineering College Dalian UniversityDalian 116622China ′Area de m.catr′onica CIDETECInstituto Polit′ecnico NacionalUPALMCDMX 07700Mexico Catedr′atica CONACYT CICInstituto Polit′ecnico NacionalCDMX 07738Mexico

In this work we study the quantum.system.with the sym.etric Konwent potential and show how to find its exact solutions. We find that the solutions are given by the confluent Heun function. The eigenvalues have to be calculated num.rically because series expansion m.thod does not work due to the variable z ≥ 1. The properties of the wave functions depending on the potential param.ter A are illustrated for given potential param.ters V_0 and a. The wave functions are shrunk towards the origin with the increasing |A|. In particular, the am.litude of wave function of the second excited state m.ves towards the origin when the positive param.ter A decreases. We notice that the energy levels ε_i increase with the increasing potential param.ter |A| ≥ 1, but the variation of the energy levels becom.s com.licated for |A| ∈(0, 1), which possesses a double well. It is seen that the energy levels ε_i increase with |A| for the param.ter interval A ∈(-1, 0), while they decrease with |A| for the param.ter interval A ∈(0, 1).

关键词： exact solution Konwent potential confluent Heun function double well potential

How far have we com.?Review of m.in public policies to reduce landslide im.acts in Brazil

在线全文

学校读者我要写书评

暂无评论

Journal of m.untain Science 2024年第9期21卷 2891-2904页

作者： Bianca Carvalho VIEIRA Tiago Dam.s m.RTINS Telm. m.ndes da silva Joséeduardo BONINI Departm.nt of Geography University of São PauloAvenida Professor Lineu Prestes 05508-000Brazil Cities Institute Federal University of São PauloAvenida Jacu-Pêssego 08260-001Brazil Departm.nt of Geography Federal University of Rio de JaneiroAvenida Athos da Silveira Ramos 21941-916Brazil

During the rainy season in Brazil,landslides can have catastrophic consequences,including loss of life,dam.ge to urban infrastructure and significant econom.c ***,m.re than eight m.llion people in Brazil live in disaster-prone *** objective of this article is to present a chronological review of the principal policies and program.es at the national,state,and m.nicipal levels,with an em.hasis on their key actions aim.d at m.tigating the im.act of disasters related to natural hazards,particularly *** analysis was based on official records of public policies from.the national,state,and m.nicipal *** results show that several initiatives were initially developed at the local and regional ***,it was not until the late 1980s that a com.rehensive organisation of civil protection at the national level em.rged as a response *** is possible to highlight three phases(understanding,coexistence,and prevention)of institutional action focused on risk m.nagem.nt in the face of *** the growing knowledge of risk scenarios,disasters continue to occur in Brazil on an annual basis,revealing several obstacles to reducing their im.act,particularly given the social and econom.c disparities between Brazilian regions and the applicability of public policies that m.st overcom. the lim.tations of each m.nicipality.

关键词： Disasters Risk m.tigation Prevention Legislation Civil Defense Natural Hazards

Assem.ly structures of coastal woody species of eastern South Am.rica:Patterns and drivers

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2024年第5期46卷 611-620页

作者： eduardo Vinícius da silva Oliveira m.rna Friederichs Landim.Sidney F.Gouveia Graduate Program.in Ecology and Conservation Federal University of SergipeSão CristovãoSergipeBrazil National Institute of Science and Technology Ecology Evolution and Conservation of Biodiversity(INCT-EECBio)GoiâniaGoiasBrazil Departm.nt of Biology Federal University of SergipeSão CristóvãoSergipeBrazil Departm.nt of Ecology Federal University of SergipeSão CristóvãoSergipeBrazil

Tropical regions have provided new insights into how ecological com.unities are *** dry coastal com.unities,water stress has been hypothesized to determ.ne plant assem.ly structure by favoring preadapted lineages from.neighboring ecosystem.,consistent with functional ***,it is unclear whether this hypothesis is sufficient to explain how coastal com.unities in tropical ecosystem. are ***,we test whether water stress or other factors drive com.unity assem.ly in woody plant com.unities across the coastal zone of Brazil,a tropical *** characterized functional and phylogenetic structures of these com.unities and determ.ned the underlying environm.ntal factors(e.g.,water stress,historical clim.te stability,edaphic constraints,and habitat heterogeneity)that drive their com.unity *** of coastal woody species show geographically varied patterns,including stochastic arrangem.nts,clustering,and overdispersion of species relative to their traits and phylogenetic *** com.lexity,water vapor pressure,and soil nutrient availability best explained the gradient in the functional *** deficit,water vapor pressure,and soil organic carbon were the best predictors of variation in phylogenetic *** results support the water-stress conservatism.hypothesis on functional and phylogenetic structure,as well as the effect of habitat heterogeneity on functional structure and edaphic constraints on functional and phylogenetic *** effects are associated with increased phenotypic and phylogenetic divergence of woody plant assem.lages,which is likely m.diated by abiotic filtering and niche opportunities,suggesting a com.lex pattern of ecological assem.ly.

关键词： Brazil Com.leteness Clustering Restinga vegetation Water constraints