检索结果-南通市图书馆

Analysis of Operating Variables in the Catalytic Purification of Butene-1 in a Trickle Bed

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 1998年第2期6卷 13-25页

作者： Sergio P.Bressa Néstor O.Ardiaca osvaldo m.martinez Guillermo F.Barreto Depto.de Ing.Qca. Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-Argentina

A mathematical model for analyzing and simulating selective hydrogenation of butyne-1 and 1,3-bu-tadiene in industrial trickle bed reactors operated to obtain high purity butene-1 is presented in this *** analysis of typical operating conditions,only the relevant phenomena are finally retained in the model *** model is then employed to analyze the effect of operating variables and catalyst selectivity in *** particular,the search for the minimum hydrogen flow rate necessary to fulfil butene-1 purityspecifications is undertaken.

关键词： selective hydrogenation butene-1 1 3-butadiene trickle bed reactor

An egg-shell bifunctional CeO_(2)-modified NiPd/Al_(2) O_(3) catalyst for petrochemical processes involving selective hydrogenation and hydroisomerization

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第11期39卷 1382-1388,I0003页

作者： Franklin J.mendez Javier A.Alves Yahse Rojas-Challa Oscar Corona Yanet Villasana Julia Guerra German Garcia-Colli osvaldo m.martinez Joaquin L.Brito Centro de Quimica Instituto Venezolano de Invesdgaciones CientfficasCarretera PanamericanaKm 11 Altos de PipeCaracas1020AVenezuela Departamento de Estado Solido Instituto de FisicaUniversidad Nacional Autonoma de MexicoCiudad UniversitariaCiudad de Mexico04510Mexico Departamento de Ingenieria Quimica Facultad de Ingenieria(UNLP)and Centro de Investigacion y Desarrollo en Ciencias Aplicadas"Dr.J.J.Ronco"(CINDECA)CCT-La Plata-CONICET-UNLPLa Plata1900Argentina Departamento de Quimica Analitica Facultad de QufmicaUniversidad Nacional Autonoma de MexicoCiudad UniversitariaCiudad de Mexico04510Mexico Instituto Tecnoldgico Venezolano Del Petroleo SA. Petrole os de Venezuela SA.Urb.Santa Rosa-Sector El TamborLos Teques1201Venezuela Instituto Superior de Formacion Docente Salome Urena Esquina Leonardo D'VinciSanto Domingo10114Republica Dominicana Biomass to Resources Group Universidad Regional Amazonica IkiamKm 7 via MuyunaTena150150Ecuador Departamento de Termodinamica y Fenomenos de Transferencia Universidad Simon BolivarValle de SartenejasCaracas1086Venezuela

The catalytic performance during the 1-butyne hydrogenation using two reduced Al_(2) O_(3)-supported Pdbased catalysts was carried out in a total recirculation system with an external fixed-bed *** lab-prepared egg-shell NiPd/CeO_(2)-Al_(2) O_(3) catalyst(NiPdCe) with Pd loading=0.5 wt%,Ni/Pd atomic ratio=1 and CeO_(2) loading=3 wt% was synthesized and characterized,and it was compared with an egg-shell Al_(2) O_(3)-supported Pd based commercial catalyst(PdCC).The reduced catalysts were characterized by X-ray diffraction,X-ray photoelectron spectroscopy,and high-resolution transmission electron *** textural characteristics and ammonia temperature-programmed desorption profiles of the fresh(unreduced) catalysts were also *** catalysts show high 1-butyne conversion and selectivity to 1-butene,but the catalysts also present important differences between hydroisomerizing and hydrogenating *** catalyst shows higher capability for hydroisomerization reactions,while the PdCC catalyst exhibits higher hydrogenating *** observed catalytic performances can be interesting for some industrial processes and can provide a guideline for the development of a Pd-based catalyst with specific catalytic properties.

关键词： 1-Butyne Bifunctional catalyst Egg-shell Hydrogenation Hydroisomerization NiPd catalyst

Seismic response of deep circular tunnels subjected to S-waves:Axial bending

在线全文

学校读者我要写书评

暂无评论

Underground Space 2024年第4期17卷 267-279页

作者： Chatuphat Savigamin Antonio Bobet osvaldo P.m.Vitali HR Engineering Services Inc.MedleyFL 33166United States Lyles School of Civil Engineering Purdue UniversityWest LafayetteIN 47907United States Department of Civil Environmentaland Construction EngineeringUniversity of Hawaii at ManoaHonoluluHI 96822United States

Ovaling deformation of circular tunnels has received great interest from the tunneling community because this mode of seismicinduced deformation is considered the most ***,there is growing evidence that other deformation modes can also be important and thus need to be considered in *** study presents a new analytical solution to estimate axial bending(snaking),a mode of deformation caused by S-waves impinging on a tunnel parallel to the tunnel *** solution is developed using the soilstructure interaction approach with the assumption that the interface between the ground and the tunnel lining is frictionless(fullslip).Full dynamic numerical simulations are conducted to verify the new full-slip solution,together with the existing no-slip *** of dynamic amplification are also explored for both full-slip and no-slip interface conditions by changing the wavelength(or frequency)of the seismic input motions.

关键词： Seismic response of tunnels Analytical solutions Soil-structure interaction Axial bending Snaking S-waves

Behavior of tunnels excavated with dip and against dip

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2021年第6期6卷 709-717页

作者： osvaldo P.m.Vitali Tarcisio B.Celestino Antonio Bobet Lyles School of Civil Engineering Purdue UniversityWest LafayetteIN 47907USA Sao Carlos School of Engineering University of Sao PauloSao CarlosSP 13566Brazil

Rock masses with remarked rock structure are likely to be highly anisotropic;thus,the relative orientation of the tunnel with respect to the rock structure will affect the tunnel *** measured at the walls of tunnels in highly anisotropic rock masses often reveal an asymmetric deformation pattern around the tunnel perimeter,which is often interpreted as the result of rock heterogeneity or changing ***,numerical and analytical investigation of tunnels in anisotropic rock masses show that the tunnel axis misalignment with the principal directions of stress and material anisotropy induce anti-symmetric axial displacements(i.e.,axial distortion of the tunnel cross section)far behind the tunnel *** the face,the axial distortion is partially constrained,causing asymmetric radial *** this study,tunnels excavated with and against dip of the major rock mass discontinuity are explored using 3D FEm modeling.A detailed analysis on the mechanisms associated with the direction of excavation is *** is shown that the asymmetric displacements near the face may strongly affect the displacements measured at the tunnel walls,which may explain the asymmetric displacements commonly observed on tunnels in anisotropic rock.

关键词： Tunnel Tunnel misalignment Anisotropic rock Face effects

3D finite element modelling optimization for deep tunnels with material nonlinearity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2018年第2期3卷 125-139页

作者： osvaldo P.m.Vitali Tarcisio B.Celestino Antonio Bobet Lyles School of Civil Engineering Pwrdue UniversityWest LafayetteIN 47907USA Sao Carlos School of Engineering.Univerity of Sao Paulo Sao CarlosSP 13566Brazil

3D modeling of tunnels using a nonlinear ground model is still a time-consuming task because it usually requires a large number of incremental phases with iterative processes,to ensure accuracy while minimizing computational *** of theﬁnite element mesh is of utmost *** the current tendency towards 3D modeling of tunnels,few publications are concerned with mesh optimization considering model size,grid reﬁnement and order of *** paper improves the understanding of key issues that affect 3D modeling of *** results shown that:(1)2nd order elements are more effcient when material nonlinearity is present and should be preferred;(2)the plastic zone size has a strong inﬂuence on the model dimensions and may require discretizations much larger than those currently *** paper provides recommendations for mesh reﬁnement and model dimensions(width and length)as a function of the plastic zone size,for accurate 3D models with reduced computational cost.

关键词： Tunnel Numerical modeling Finite element method mesh optimization Nonlinear material

Construction strategies for a NATm tunnel in Sao Paulo, Brazil, in residual soil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2022年第1期7卷 1-18页

Due to the fast growth of urban areas worldwide,the demand for tunnels in developed areas is *** design and construc-tion of those tunnels are complex because of their shallow depths and their interaction with existing aboveground and buried structures,which results in rather limited allowable ground deformations induced by the tunnel excavation and *** tropical regions,residual porous soils near the surface are *** soils are highly deformable;thus,tunneling may induce large ground deformations that may damage nearby *** new Austrian tunneling method(NATm)and the sprayed concrete lining(SCL)technique are being widely employed in several big cities in tropical regions,but little research has been conducted to assess the induced ground deformations in residual soils,common in tropical *** paper provides insight into this issue.A well-documented metro tunnel in Sa˜o Paulo,Brazil,in a residual red porous clay,was analyzed using 3D finite element method(FEm).The behavior of the residual red porous clay was approximated by an advanced constitutive soil model calibrated with triaxial tests on intact samples extracted at the *** of the tunnel deformations during construction matched the field *** calibrated model was then used to explore the tunnel per-formance under different construction *** influence of partial face excavation,unsupported span length,support stiffness and pipe roof umbrella were *** numerical results showed that partial face excavation was effective to reduce ground deformations ahead of the face of the tunnel and to improve face stability;however,the settlements behind the face increased because of the delay in closing the primary *** installation of a stiffer liner closer to the face reduced the ground deformations *** pipe roof umbrella was the most effective technique to reduce the ground deformations around the tunnel;however,the numerical results

关键词： Tunnel NATm Residual soil FEm 3D face effects Ground deformation Face stability

Life cycle assessment of low impact development technologies combined with conventional centralized water systems for the City of Atlanta, Georgia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2016年第6期10卷 3-15页

作者： Hyunju Jeong osvaldo A. Broesicke Bob Drew Duo Li John C. Crittenden Department of Civil and Environmental Engineering South Dakota School of Mines and Technology Rapid City SD 57701 USA Brook Byers Institute for Sustainable Systems School of Civil and Environmental Engineering Georgia Institute of Technology 828 West Peachtree Street Suite 320 Atlanta GA 30332-0595 USA ECOVIE Rainwater Collection Systems 4287 Club Drive N.E. Atlanta GA 30319 USA Crittenden and Associates C-305 Building E Wangjing High-tech Park LizezhongEr Road Chaoyang District Beijing 100102 China

Low-impact development （LID） technologies, such as bioretention areas, rooftop rainwater harvesting, a_nd xeris_caping can co_ntrol stormwater runoff, supply non-potable water, and landscape open *** study examines a hybrid system （HS） that combines LID technologies with a centralized water system to lessen the burden on a conventional system （CS）. CS is defined as the stormwater collection and water supply infrastructure, and the conventional landscaping choices in the City of Atlanta. The study scope is limited to five single-family residential zones （SFZs）, classified R-1 through R-5, and four multi-family residential zones （mFZs）, classified RG-2 through RG-5. Population density increases from 0.4 （R-1） to 62.2 （RG-5） persons per 1,000 m2. We performed a life cycle assessment （LCA） comparison of CS and HS using TRACI 2.1 to simulate impacts on the ecosystem, human health, and natural resources. We quantified the impact of freshwater consumption using the freshwater ecosystem impact （FEI） indicator. Test results indicate that HS has a higher LCA single score than CS in zones with a low population density; however, the difference becomes negligible as population density increases. Incorporating LID in SFZs and mFZs can reduce potable water use by an average of 50%. and 25%,respectively.; however, water savings are negligible in zones with high population density （i.e., RG-5） due to the diminished surface area per capitaavailable for LID technoogies. The results demonstrate that LID technologies effectively reduce outdoor water demand and therefore would be a good choice to decrease the water consumption impact in the City of Atlanta.

关键词： Life cycle assessment (LCA) Low impact development (LID) Bioretention area Rainwater harvesting Xeriscaping

Exergames： neuroplastic hypothesis about cognitive improvement and biological effects on physical function of institutionalized older persons

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2016年第2期11卷 201-204页

作者： Renato Sobral monteiro-Junior Cesar Augusto Otero Vaghetti osvaldo Jose m. Nascimento Jerson Laks Andrea Camaz Deslandes Physical Education and Sport Department of the Universidade Estadual de montes Claros Minas GeraisBrazil Post Graduation Program(PhD)in medicine(Neurology-Neuroscience) Universidade Federal FluminenseNiteroiBrazil Neuroscience Laboratory of Exercise Universidade Federal do Rio de JaneiroRio de JaneiroBrazil Higher School of Physical Education Universidade Federal de PelotasPelotasBrazil Neurology Department Universidade Federal FluminenseNiteroiBrazil Programa de Pos-graduacao em Biomedicina Translacional-Biotrans Universidade UnigranrioBrazil Institute of Psychiatry UniversidadeFederal do Rio de JaneiroRio de JaneiroBrazil Centro de Estudos e Pesquisa do Envelhecimento Instituto Vital BrasilRio de JaneiroBrazil Institute of Physical Education and Sport Universdiade do Estado do Rio de JaneiroRio de JaneiroBrazil

Exergames can be considered a dual task because the games are performed by a man-videogame interface, requiring cognitive and motor functions simultaneously. Although the literature has shown improvements of cognitive and physical functions due to exergames, the intrinsic mechanisms involved in these functional changes have still not been elucidated. The aims of the present study were（1） to demonstrate the known biological mechanisms of physical exercise regarding muscle adaptation and establish a relationship with exergames; and（2） to present a neurobiological hypothesis about the neuroplastic effects of exergames on the cognitive function of institutionalized older persons. These hypotheses are discussed.

关键词： virtual reality elderly nursing-home physical activity cognition neuroplasticity

Biliary acute pancreatitis:a review

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2000年第2期6卷 157-168页

作者： osvaldo m.Tiscomia Susana Hamamura Enriqueta S.deLehmann Graciela Otero Hipolito Waisman Patricia Tiscornia-Wasserman Simmy Bank "Programade Estudios Pancreáticos" Hospital de ClínicasUniversidad de Bs.As.Argentina Centro de Investigaciones Pancreáticas"(CIP)Hospital de ClínicasUniv.de Buenos AiresArgentina Research Member of CONICETBuenos AiresArgentina "Programade Estudios Pancreáticos" Hospital de ClínicasUniversidad de Bs.As.Argentina "Centro de Investigaciones Pancreáticas"(CIP)Hospital de ClínicasUniv.de Buenos AiresArgentina "Programa de Estudios Pancreáticos" Hospital de ClínicasUniversidad de Bs.As.Argentina "Centro de Investigaciones Pancreáticas"(CIP)Hospital de ClínicasUniv.de Buenos AiresArgentina Chief of Cytology Department of PathologyLong Island Jewish Medical Center (LIJ) NYUSA Chief Department of Gastroenterology Long Island Jewish Medical Center (LIJ) NYUSA

INTRODUCTIONIt is axiomatic that the most effective and soundlybased plan of treatment of any disorder is one aimedat the mechanism or mechanisms responsible for *** basic notion,coupled withrecent reports in which,su... 详细信息

关键词： cholelithiasis/physiopathology pancreatitis/physiopathology bile reflux common bile duct sphincterotomy endoscopic