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Application of the extended Fourier amplitude sensitivity testing(FAST)method to inflated,axial stretched,and residually stressed cylinders

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Applied Mathematics and Mechanics(English Edition) 2023年第12期44卷 2139-2162页

作者： H.ASGHARI H.TOPOL B.MARKERT J.MERODIO departamento de Matemática Aplicada a las TIC ETS de Ingenier a de Sistemas InformáticosUniversidad Politécnica de MadridMadrid 28031Spain Institute of General Mechanics RWTH Aachen UniversityAachen 52062Germany

This paper is dedicated to applying the Fourier amplitude sensitivity test(FAST)method to the problem of mixed extension and inflation of a circular cylindrical tube in the presence of residual stresses.The metafunctions and the Ishigami function are considered in the sensitivity analysis(SA).The effects of the input variables on the output variables are investigated,and the most important parameters of the system under the applied pressure and axial force such as the axial stretch and the azimuthal stretch are determined.

关键词： sensitivity analysis(SA) Fourier amplitude sensitivity test(FAST)method cylindrical inflation nonlinear elasticity

Habitat use and space preferences of Eurasian Bullfinches(Pyrrhula pyrrhula)in northwestern Iberia throughout the year

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Avian Research 2021年第1期12卷 37-51页

作者： Angel Hernández departamento de Ciencias Agroforestales Area de ZoologiaUniversidad de ValladolidCampus de PalenciaPalenciaEspana Instituto Universitario de Investigacion en Gestion forestal Sostenible Universidad de ValladolidCampus de PalenciaPalenciaEspana

Background:For all vertebrates in general,a concerted effort to move beyond single season research is vital to improve our understanding of species ecology.Knowledge of habitat use and selection by Eurasian Bullfinches(Pyrrhula pyrrhula)is limited with regard to the non-breeding season.To date,research on the habitat of the Iberian subspecies iberiae consists of very general descriptions.In relation to space use,only broad features are available for the entire distribution range of Eurasian Bullfinches,including Iberia.Methods:In this study,seasonal preferences regarding habitat and space in a population of Eurasian Bullfinches are examined for the first time in the Iberian Peninsula,through direct observation during a six-year period.The essential habitat components,substrate selection and perch height were assessed.Results:Hedgerows were the key essential habitat component for bullfinches during all seasons.Nevertheless,small poplar plantations became increasingly important from winter to summer-autumn.Bullfinches perched mostly in shrubs/trees throughout the year,but there were significant seasonal changes in substrate use,ground and herbs being of considerable importance during spring-summer.Throughout the year,over half of the records corresponded to feeding,reaching almost 90%in winter.Generally,bullfinches perched noticeably lower while feeding.Male bullfinches perched markedly higher than females,notably singing males in spring-summer.Juveniles perched at a height not much lower than that of males.In all seasons,males tended to feed at greater heights than females.Bullfinches of different ages and sexes were seen bathing in all seasons except winter.Conclusions:Hedgerow habitat in general appeared to be valuable for bullfinches throughout the year.In summer and autumn,they selected sites with an abundance of food and shade,as well as shelter,a much-needed requirement for fledglings and moulting individuals.There was usually a close link between the most used and most consumed plant species in each season.

关键词： Habitat use Perch height Pyrrhula pyrrhula iberiae Seasonal variation Substrate selection Water bathing

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热机械化学法制备Ag-ZnO粉末（英文）

Transactions of Nonferrous Metals Society of China 2019年第2期29卷 365-373页

作者： D.GUZMáN C.AGUILAR P.ROJAS J.M.CRIADO M.J.DIáNEZ R.ESPINOZA A.GUZMáN C.MARTíNEZ departamento de ingeniería en Metalurgia Universidad de Atacama departamento de ingeniería Metalúrgica y de Materiales Universidad Técnica Federico Santa María Escuela de Dise?o Universidad Adolfo Ibá?ez Instituto de Ciencias de Materiales de Sevilla C.S.I.C departamento de Ciencia de los Materiales Universidad de Chile Laboratorio de Corrosión Instituto de QuímicaPontificia Universidad Católica de Valparaíso

Ag-CdO复合材料由于其优异的电气和力学性能,仍然是低压应用中最常用的电触头材料之一。然而,考虑到由于镉的毒性而对其应用的限制,有必要寻找可取代这种复合材料的替代材料。本研究以Ag-Zn固溶体为原料,采用热机械化学工艺制备Ag-ZnO... 详细信息

Ag-CdO复合材料由于其优异的电气和力学性能,仍然是低压应用中最常用的电触头材料之一。然而,考虑到由于镉的毒性而对其应用的限制,有必要寻找可取代这种复合材料的替代材料。本研究以Ag-Zn固溶体为原料,采用热机械化学工艺制备Ag-ZnO合金。在138°C、1200 cm^3/min的氧气流下,在改进的球磨机中对合金样品进行热机械化学处理3 h,利用X射线衍射技术、场发射扫描电镜和透射电镜对合成材料的显微组织和相演变进行研究。结果表明,低温下的热机械化学处理可使Ag-Zn固溶体在短时间内完全氧化。这种新的合成方法可以制备出纳米ZnO相均匀分布的Ag-ZnO复合材料,而这是用传统的材料加工方法无法实现的。考虑到改善电触头材料性能的根本途径在于实现Ag基体中第二相的均匀分散,这一新工艺为Ag-ZnO复合材料取代非环境友好的Ag-CdO提供了可能。

关键词： Ag-ZnO 纳米复合材料电触头材料粉末合成球磨

Corrosion protection of AZ91D magnesium alloy by a cerium-molybdenum coating-The effect of citric acid as an additive

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Journal of Magnesium and Alloys 2018年第4期6卷 356-365页

作者： I.L.Lehr S.B.Saidman Instituto de ingeniería Electroquímica y Corrosión(INIEC) Departamento de Ingeniería QuímicaUniversidad Nacional del Sur(UNS)CONICETBahía BlancaArgentina

In order to improve the corrosion resistance of AZ91D magnesium alloy,a coating was formed by a potentiostatic technique from a solutions containing Ce(NO_(3))_(3),Na_(2)MoO_(4)and citric acid(H_(3)Cit).The degree of corrosion protection achieved was evaluated in simulated physiological solution by monitoring the open circuit potential,polarization techniques and electrochemical impedance spectroscopy(EIS).Surface analysis techniques(SEM,EDS,X-ray diffraction and X-ray photoelectron spectroscopy(XPS))were used for coating characterization.The film is mainly composed by cerium and molybdenum oxides and magnesium oxides and hydroxides.The obtained results show that the corrosion resistance of the coated electrodes has been increased significantly.This improvement in the anticorrosive performance is in part due to the corrosion inhibition properties of H_(3)Cit.

关键词： Cerium and molybdenum-based coatings AZ91D alloy Citric acid Anticorrosive properties

Analysis of the role of diffraction in topographic site effects using boundary element techniques

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Earthquake Science 2013年第5期26卷 341-350页

作者： Juan Gomez Doriam Restrepo Juan Jaramillo Camilo Valencia departamento de ingeniería Civil Universidad EAFITMedellín Colombia

The role played by the diffraction field on the problem of seismic site effects is studied. For that purpose we solve and analyze simple scattering problems under P and SV in-plane wave assumptions, using two well known direct boundary-element-based numerical methods. After establishing the difference between scattered and diffracted motions, and introducing the concept of artificious and physically based incoming fields, we obtain the amplitude of the Fourier spectra for the diffracted part of the response： this is achieved after establishing the connection between the spatial distribution of the transfer function over the studied simple topographies and the diffracted field. From the numerical simulations it is observed that this diffracted part of the response is responsible for the amplification of the surface ground motions due to the geometric effect. Furthermore, it is also found that the diffraction field sets in a fingerprint of the topographic effect in the total ground motions. These conclusions are further supported by observations in the time-domain in terms of snapshots of the propagation patterns over the complete computational model. In this sense the geometric singularities are clearly identified as sources of diffraction and for the considered range of dimensionless frequencies it is evident that larger amplifications are obtained for the geometries containing a larger number of diffraction sources thus resulting in a stronger topographic effect. The need for closed-form solutions of canonical problems to construct a robust analysis method based on the diffraction field is identified.

关键词： Seismic site effects Topographiceffects Elastic wave scattering Diffractionof in-plane waves

Envelopes of Commutative Rings

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Acta Mathematica Sinica,English Series 2012年第3期28卷 561-580页

作者： Rafael PARRA Manuel SAORIN departamento de Clculo. Escuela Bsica Facultad de Ingeniería Universidad de los Andes departamento de Matemticas Universidad de Murcia

Given a significative class F of commutative rings, we study the precise conditions under which a commutative ring R has an S-envelope. A full answer is obtained when F is the class of fields, semisimple commutative rings or integral domains. When .F is the class of Noetherian rings, we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic. The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope, which we conjecture is the empty class.

关键词： Noetherian ring envelope local ring artinian ring Krull dimension

Adsorbents derived from Xylan Hemicellulose with Removal Properties of Pollutant Metals

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Chinese Journal of Polymer Science 2023年第6期41卷 874-886,I0007页

作者： Elizabeth Elgueta Yerko Becerra Ana Martínez Miguel Pereira Isabel Carrillo-Varela Felipe Sanhueza Dariela Nuez BernabéL.Rivas Centro de Investigación de Polímeros Avanzados CIPAAvenida Collao 1202Edificio de LaboratoriosConcepcionChile departamento de Química Ambiental Facultad de CienciasUniversidad Católica de la Santísima ConcepciónCaila 160-cConcepcionChile Polymer department Faculty of ChemistryUniversity of ConcepciónCasilla 160-CConcepcionChile departamento de ingeniería Química Facultad de IngenieríaUniversidad de ConcepciónConcepcionChile department of Materials Engineering Faculty of EngineeringUniversidad de ConcepciónConcepcionChile

The adsorption capacity of hydrogels derived from modified xylan hemicellulose has been tested in order to develop new bio-based adsorbent materials useful for removing metal ions pollutants,such as Cd(Ⅱ),Cu(Ⅱ)and Pb(Ⅱ)from an aqueous solution.Xylan was extracted from bleached kraft pulp of eucalyptus and subsequently modified with different proportions of functional sulfonic acid groups(HA3-HA7)and sulfonate groups(HS30-HS70)to generate hydrogels.The results showed that all the synthesized hydrogels were capable of adsorbing metal ions,being the hydrogels with 30%and 50%xylan the ones that presented the highest adsorption capacity.Maximum capacity studies at different initial concentrations revealed that at an initial concentration of 300 mg·L-1,the HA3 hydrogel presented an adsorption capacity of 193mg Pb(Ⅱ),182 mg Cd(Ⅱ),and 66 mg Cu(Ⅱ)per g hydrogel.The HA5 hydrogel presented a capacity of 185 mg Pb(Ⅱ),113 mg Cd(Ⅱ),and 48 mg Cu(Ⅱ)per g hydrogel.The HS30 hydrogel exhibited an adsorption of 205 mg Pb(Ⅱ),174 mg Cd(Ⅱ),and 71 mg Cu(Ⅱ)per g hydrogel,and HS50 hydrogel exhibited an adsorption capacity of 273 mg Pb(Ⅱ),143 mg Cd(Ⅱ),and 45 mg Cu(Ⅱ)per g hydrogel.These results show that modified Xylan hemicellulose is a promising adsorbent for removal Cd(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ)ions from aqueous solutions.

关键词： Pb(Ⅱ) solution capacity

Pisco grape pomace:Iron/copper speciation and antioxidant properties,towards their comprehensive utilization

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Food Bioscience 2022年第3期47卷 1213-1221页

作者： Fátima Rodríguez-Ramos Raúl Cañas-Sarazúa Vilbett Briones-Labarca departamento de ingeniería en Alimentos Universidad de La SerenaAv.Raúl Bitrán Nachary 1305Box 5991720010La SerenaChile

The pisco and wine industry produces hundreds of tons of grape pomace each year in Chile,generating environmental problems,and demanding urgent strategies for its management.The aim of this work was to study the pisco grape pomace based on a physicochemical characterization,an iron/copper speciation analysis,and the optimization for polyphenols recovery,establishing the polyphenolic profile,antioxidant properties,and the Fe^(2+)/Cu^(2+) chelating activity,to promote their revalorization as an ingredient with potential application in the food industry.The chemical characterization showed mainly high values for crude protein(15.36%dw)and potassium(9240.66 mg/kg).The Fe/Cu speciation depicted that iron and copper soluble forms in pisco pomace flour represented 70.57%and 52.18%,respectively,regarding total content.The optimized extract showed mainly pyrogallol,catechin and epicatechin,with concentrations of 1078.43±60.14μg/g,883.20±7.57μg/g and,751.76±23.04μg/g,respectively,with a relevant antioxidant capacity by Oxygen Radical Absorbance Capacity(ORAC)of 1402.15μmol TE/g dw GPE and,a better chelating ability to complex Fe^(2+) than Cu^(2+).The pisco pomace was for the first time chemically characterize,showing it as a potential source of minerals and antioxidant biocompounds,making it a good candidate for nutritional applications,as a rich source of organic matter or even could be potentially utilized to produce value-added commodities,toward a circular economy.

关键词： Pisco grape pomace Polyphenols Chemical speciation analysis Antioxidant capacity Metal chelating ability

Changes in Olsen P in Relation to P Balance in Contrasting Agricultural Soils

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Pedosphere 2016年第5期26卷 636-642页

作者： Isabel DIAZ Jose TORRENT departamento de ingeniería Aeroespacial y Mecánica de Fluidos Escuela Tdcnica Superior de Ingeniería Agronómica(ETSIA)Universidad de SevillaCtra de Utrera km 141013 Sevilla(Spain) departamento de Agronomia Universidad de CordobaEdificio C4Campus de Rabanales14071 Cordoba(Spain)

Maintaining soil phosphorus(P) at adequate levels for plant growth requires assessing how the long-term P balance(viz., the difference between P inputs and outputs) results in changes in soil test P. The hypothesis that routinely measured soil properties can help predict the conversion factor of P balance into Olsen P was tested at 39 sites in agricultural areas of the Mediterranean region in Spain. A set of soil samples from each site was analyzed for Olsen P, inorganic P(P extracted using 0.5 mol L^(-1) H_2SO_4), pseudototal P(P extracted using 0.5 mol L^(-1) H_2SO_4 following ignition at 550℃), and organic P(the difference between pseudototal P and inorganic P). Organic and Olsen P were uncorrelated in most of the 39 soil sets, which suggests that organic P content changed little with P inputs and outputs. The slopes of the regression lines of Olsen P against pseudototal and inorganic P, which were used as two different measures of the conversion factor, ranged widely(from 0.03 to 0.25 approximately), with their average values(about 0.10) being similar to those found in long-term experiments conducted in temperate areas. Neither conversion factor was significantly correlated with any routinely measured soil property; however, the conversion factor for inorganic P was significantly lower for calcareous soils than for noncalcareous soils. Our negative results suggest the need to isolate the influence of soil properties from that of management systems and environmental factors relating to P dynamics in future studies.

关键词：磷素平衡农业土壤 H2SO4 土壤性质土壤测试转换因子常规测量石灰性土壤