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Theoretical and Numerical Analysis of.the Mechanical Erosion in Steam Turbine Blades. Part I

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Energy and Power Engineering 2011年第3期3卷 227-237页

作者： f. rueda martínez M. Toledo Velázquez A. A. rueda martínez f. Sánchez Silva S. Alcántara Montes O. M. Huerta Chávez 不详

The methodology of.calculation of.the velocity distribution f.r the stream f.ictionless and the drops in the f.ow line, on the basis of.the f.ictionless, two-dimensional, stationary, transonic and homogenous f.ow is established. The knowledge of.conditions that govern the low pressure section of.steam turbines in the last stage to have an approximate movement of.the droplets in the blade cascades and the accumulation of.droplets on the stator blades, f.owing through the steam, is presented. This study is used f.r developing a code in f.rtran about the velocity distribution in the output of.stator blades that have f.ow conditions of.wet steam, in order to understand the causes that originate the erosion on the blades of.the last stages in the low pressure section of.steam turbines.

关键词： Steam Turbine Drop Distribution Erosion Stator-Rotor Blade Transonic f.ow

Zebraf.sh as a possible bioindicator of.organic pollutants with ef.ects on reproduction in drinking waters

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Journal of.Environmental Sciences 2015年第7期27卷 254-260页

作者： M.martínez-Sales f.García-Ximénez f.J.Espinós Aquaculture and Environmental Research Group (ACUMA) Polytechnic University of Valencia

Organic contaminants can be detected at low concentrations in drinking water, raising concerns f.r human health, particularly in reproduction. In this respect, we attempted to use the zebraf.sh as a bioindicator to detect the possible presence of.these substances in drinking water, aiming to def.ne the most relevant parameters to detect these substances, which particularly af.ect the development and reproduction of.zebraf.sh. To this end, batches of.0 embryos with the chorion intact were cultured in drinking waters f.om dif.erent sources,throughout their f.ll lif.-cycle up to 5 months, in 20 L tanks. Six replicates were perf.rmed in all water groups, with a total of.24 aquariums. Two generations（f. and f.） were studied and the f.llowing parameters were tested： in the f. generation, survival and abnormality rates evaluated at 5 dpf.days post-f.rtilization） and at 5 mpf.months post-f.rtilization）,the onset of.spawning and the f.rtility rate f.om 3 mpf.to 5 mpf. and the sex ratio and underdeveloped specimens at 5 mpf. f.rthermore, in the f. of.spring（f.）, survival and abnormality rates were evaluated at 5 dpf.and the hatching rate at 72 hpf. These results revealed that the hatching rate is the most sensitive parameter to distinguish dif.erent levels of.ef.ects between waters during the early lif. stages, whereas the rate of.underdeveloped specimens is more suitable at later lif. stages. Regarding adult reproduction, f.rtility rate was the most sensitive parameter. The possible reversibility or accumulative nature of.such ef.ects will be studied in f.ture work.

关键词： Organic pollutants Bioindicator Development and reproduction parameters Drinking water Zebraf.sh

Photocatalytic perf.rmance of.K2Ti6O13 whiskers to H2 evolution and CO2 photo-reduction

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Journal of.Energy Chemistry 2019年第10期28卷 18-28页

作者： L. f. Garay-Rodríguez L.M.Torres-martínez E.Moctezuma f.cultad de Ingeniería Civil-Departamento de Ecomateriales y Energía Universidad Autónoma de Nuevo LeónAv. Universidad S/N Cd. UniversitariaC. P. 66455 San Nicolás de los GarzaNLMéxico f.cultad de Ciencias Químicas Universidad Autónoma de San Luis PotosíAv. Manuel Nava#6C. P.78290 San Luis PotosíSLPMéxico

K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with dif.erent particle sizes and to modif. their optical, textural and electrochemical properties. These modif.cations improved their photocatalytic activity f.r H2 evolution and CO2 photo-reduction. Long K2Ti6O13 whiskers prepared by ultrasound assisted sol-gel method are the most active photocatalysts f.r the hydrogen evolution reaction using pure water as reactant (U-SG, 10,065 μmol g^-1). In contrast, an opposite behavior was observed using a mixture of.ethanol-water, where the highest activity was achieved by the shortest and less crystalline K2Ti6O13 whiskers (C-SG, 3,2871 μmol g^-1). In case of.CO2 photo-reduction, long whiskers that were also prepared by the sono-chemical assisted sol-gel method were the most active to transf.rm CO2 to f.rmaldehyde, methane, methanol and hydrogen. The Ef. value of.this catalyst is located very close to the potential f.r f.rmaldehyde production and f.vors the selectivity to this organic product.

关键词： K2Ti6O13 Sol-gel Whiskers Hydrogen evolution CO2 reduction

Parametrization of.the Teichmüller Space of.Bordered Surf.ce NEC Groups

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Acta Mathematica Sinica,English Series 2008年第6期24卷 1039-1056页

作者： B.ESTRADA E.martínez Departamento de Matemdticas f.ndamentales UNEDPaseo Senda del Rey 928040 MadridSpain

A non-Euclidean crystallographic group f.（NEC group, f.r short） is a discrete subgroup of.isometries of.the hyperbolic plane H, with compact quotient space H/Г. These groups unif.rmize Klein surf.ces, surf.ces endowed with dianalytic structure. These surf.ces can be seen as a generalization of.Riemann surf.ces. f.ndamental polygons play an important role in the study of.parametrizations of.the Teichmuller space of.NEC groups. In this work we construct a class of.right-angled polygons which are f.ndamental regions of.bordered surf.ce NEC groups. The f.ee parameters used in the construction of.the polygons give a parametrization of.the Teichmuller space. f.om the parameters we obtain explicit matrices of.the generators of.the groups. f.nally, we give examples to exhibit how dif.erent relations between the parameters ref.ect the existence of.automorphisms on the quotient surf.ces.

关键词： non-Euclidean crystallographic groups hyperbolic polygons Klein surf.ces automorphisms of.surf.ces Teichmf.ller space

Modelling a Skin-Pass Rolling Process by Means of.Data Mining Techniques and f.nite Element Method

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Journal of.Iron and Steel Research International 2012年第5期19卷 43-49页

作者： R Escribano R Lostado f.J martínez-de-Pisón A Pernía E Vergara EDMANS Group Mechanical Engineering Department of the University of La Rioja Logroo 26004 La Rioja Spain

An experience is presented using the f.nite element method （f.M） and data mining （DM） techniques to develop models that can be used to optimieze the skin-pass rolling process based on its operating conditions. A f. model based on a real skin-pass process is built and validated. Based on this model, a group of.f. models is simulated with dif.erent adjustment parameters and with dif.erent materials f.r the sheet; both variables are chosen f.om pre-set ranges, f.om all f. model simulations, a database is generated; this database is made up of.the above mentioned adjustment parameters, sheet properties and the variables of.the process arising f.om the simulation of.the model. Various types of.data mining algorithms are used to develop predictive models f.r each of.the variables of.the *** best predictive models can be used to predict experimentally hard-to-measure variables （internal stresses, internal straine, etc.） which are usef.l in the optimal design of.the process or to be applied in real time control systems of.a skin-pass process in -plant.

关键词： skin-pass rolling predictive model f.nite element method data mining

Dipole and generalized oscillator strength derived electronic properties of.an endohedral hydrogen atom embedded in a Debye-Huckel plasma

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Matter and Radiation at Extremes 2018年第5期3卷 227-242页

作者： C.martínez-f.ores R.Cabrera-Trujillo Instituto de Ciencias f.sicas Universidad Nacional Autonoma de MexicoAp.Postal 43-8CuernavacaMorelos62251Mexico

We report electronic properties of.a hydrogen atom encaged by an endohedral cavity under the inf.uence of.a weak plasma interaction. Weimplement a f.nite-dif.erence approach to solve the Schrodinger equation f.r a hydrogen atom embedded in an endohedral cavity modeled by theWoods-Saxon potential with well depth V0, inner radius R0, thickness D, and smooth parameter g. The plasma interaction is described by aDebye-Hu¨ckel screening potential that characterizes the plasma in terms of.a Debye screening length lD. The electronic properties of.theendohedral hydrogen atom are reported f.r selected endohedral cavity well depths, V0, and screening lengths, lD, that emulate dif.erentconf.nement and plasma conditions. We f.nd that f.r low screening lengths, the endohedral cavity potential dominates over the plasma interaction by conf.ning the electron within the cavity. f.r large screening lengths, a competition between both interactions is observed. We assessand report the photo-ionization cross section, dipole polarizability, mean excitation energy, and electronic stopping cross section as f.nction of.lD and V0. We f.nd a decrease of.the Generalized Oscillator Strength (GOS) when the f.nal excitation is to an s state as the plasma screeninglength decreases. f.r a f.nal excitation into a p state, we f.nd an increase in the GOS as the endohedral cavity well-depth increases. f.r the caseof.the electronic stopping cross section, we f.nd that the plasma screening and endohedral cavity ef.ects are larger in the low-to-intermediateprojectile energies f.r all potential well depths considered. Our results agree well to available theoretical and experimental data and are af.rst step towards the understanding of.dipole and generalized oscillator strength dependent properties of.an atom in extreme conditions encagedby an endohedral cavity immersed in a plasma medium.

关键词： Oscillator strengths Debye-Huckel plasma Cavities Endohedral Energy loss Stopping power

Ecological perspectives on variable retention f.restry

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Ecological Processes 2020年第1期9卷 139-144页

作者： Guillermo J.martínez Pastur Ilkka Vanha-Majamaa Jerry f.f.anklin Centro Austral de Investigaciones Científ.cas(CADIC) Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET)Houssay 200(9410)UshuaiaTierra del FuegoArgentina Natural Resources Institute f.nland(Luke) Latokartanonkaari 9FI-00790 HelsinkiFinland School of.Environmental and f.rest Science University of WashingtonSeattleWA 98195USA

f.rest management globally af.ects the ecosystem services,especially those related to ecosystem f.nctioning and biodiversity conservation,by altering f.rest structure and *** degree of.alteration was related to the intensity and type of.harvesting;theref.re,the major silvicultural challenge is to develop alternatives to mitigate climate change and maintain f.rest f.nctions and biodiversity while also providing acceptable levels of.timber *** retention f.restry(VRf.is a highly f.exible concept,with continuity of.f.rest cover,structure,f.nction,and species composition,thereby supporting multiple economic,environmental,and cultural *** special issue provides an overview of.the concepts and applications related to VRf.implementation around the *** shows that VRf.has been applied globally f.r several decades,with varying levels and retention types,depending on local conditions and the economic importance of.*** challenges of.VRf.seem to dif.er to some extent on dif.erent continents,yet the general aims have been accepted in most of.the *** has been successf.l in mitigating many ef.ects of.intensive harvesting,though in some f.rests of.the world,the retention levels are too low to maintain acceptable levels of.biodiversity and ecosystem *** conclude that an active collaboration between scientists and f.rest practitioners is needed to realize all of.the opportunities provided by VRf.in solving global f.restry-related issues.

关键词： Sustainable f.restry Biodiversity conservation Timber production Aggregated retention Dispersed retention f.rest certif.cation Prescribed burning Synergies and trade-of.s

A stable anthraquinone-derivative cathode to develop sodium metal batteries: The role of.ammoniates as electrolytes

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Journal of.Energy Chemistry 2023年第2期77卷 572-580,I0015页

作者： Débora Ruiz-martínez José M.Orts Roberto Gómez Departament de Química f.sica i Institut Universitari d’Electroquímica Universitat d’AlacantApartat 99Alicante E-03080Spain

Rechargeable sodium metal batteries constitute a cost-ef.ective option f.r energy storage although sodium shows some drawbacks in terms of.reactivity with organic solvents and dendritic *** we demonstrate that an organic dye,indanthrone blue,behaves as an ef.icient cathode material f.r the development of.secondary sodium metal batteries when combined with novel inorganic *** electrolytes are ammonia solvates,known as liquid ammoniates,which can be f.rmulated as NaI·3.3NH_(3) and NaBf.(4)·2.5NH_(3).They impart excellent stability to sodium metal,and they f.vor sodium non-dendritic growth linked to their exceedingly high sodium ion *** advantage is complemented by a high specif.c *** battery described here can last hundreds of.cycles at 10 C while keeping a Coulombic ef.iciency of.99%f.om the f.rst *** of.the high capacity of.the cathode and the superior physicochemical properties of.the electrolytes,the battery can reach a specif.c energy value as high as 210 W h kgIB^(-1),and a high specif.c power of.2.2 kW kgIB^(-1),even at below room temperature(4℃).Importantly,the battery is based on abundant and cost-ef.ective materials,bearing promise f.r its application in large-scale energy storage.

关键词： Sodium metal batteries Anthraquinone-based cathode Vat dye Indanthrone blue Inorganic electrolytes Liquid ammoniates

Ef.ect of.airf.ow on biodrying of.gardening wastes in reactors

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Journal of.Environmental Sciences 2013年第5期25卷 865-872页

作者： f.J.Colomer-Mendoza L.Herrera-Prats f.Robles-martínez A.Gallardo-Izquierdo A.B.Pia-Guzmn Department of.Mechanical Engineering and Construction (Universidad Jaume I)Jaume 1st University.Ave.Sos Baynat s/nCastellón 12071Spain Biotechnology Multidisciplinary Prof.ssional Unit (Instituto Politcnico Nacional)National Politechnic Institute.Ave.Acueduct of Guadalupe s/n Barrio la Laguna TicomnGustavo A.Madero 07340Mxico DF.Mxico

Biodrying consists of.reducing moisture by using the heat f.om aerobic *** parameters that control the process are：aeration,temperature during the process,initial moisture of.biowaste,and temperature and relative humidity of.the input *** mowing and garden waste f.om the gardens of.the University Jaume I,Castellón（Spain）were used as a *** was perf.rmed in 10 reactors with known air volumes f.om 0.88 to 6.42 L/（min·kg dry weight）.To promote aeration,5 of.the reactors had 15% of.a bulking agent *** experiment lasted 20 *** the experiments it was f.und that the bulking agent led to greater weight ***,the increased airf.ow rate was not linearly proportional to the weight loss.

关键词： biodrying biowaste stabilization aerobic f.rmentation bulking agent