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DAmAGE mECHANISmS OF INCONEL 738LC UNDERCREEP-FATIGUE LOADING CONDITIONS

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Acta metallurgica Sinica(English Letters) 1998年第6期11卷 470-476页

作者： m.Yamamoto T.Ogata Central Research Inst of Electric Power Industry Tokyo Japan

In order to investigate creep-fatigue life characteristics of InConel 738LC, fatigue and creep-fatigue tests were carried out at 850 degree C. Significant life reduction to 30% to 50% of normal fatigue life, occurred when a strain hold period was introduced at the minimum compressive strain. Test results show that the degree of life reduction does not depend on the scale of hold time. To clarify the creep-fatigue damage mechanisms under creep-fatigue loading, in-situ SEm observations were carried out during the tests. In the tensile strain hold test, multi-site grain boundary cracking was observed from the beginning of the test. On the other hand, only a single main crack was observed in the compressive strain hold test. The crack propagates in an intergranular manner, and it is different from the features observed under cyclic fatigue conditions. Through the detailed observations, it was found that the grain boundary sliding damage occurs at most surface grain boundaries. (Edited author abstract) 5 Refs.

关键词： superalloy creep-fatigue grain boundary sliding

Ergodicity and Accuracy of Optimal Particle Filters for Bayesian Data Assimilation

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Chinese Annals of mathematics,Series B 2019年第5期40卷 811-842页

作者： David KELLY Andrew m.STUART Courant Institute of mathematical Sciences New York UniversityNew YorkUSAThe Voleon Group2150 Dwight WayBerkeleyCA94704USA Department of Computing and mathematical Sciences California Institute of TechnologyPasadenaCA91125USA.

Data assimilation refers to the methodology of combining dynamical models and observed data with the objective of improving state estimation. most data assimilation algorithms are viewed as approximations of the Bayesian posterior(filtering distribution)on the signal given the observations. Some of these approximations are controlled, such as particle filters which may be refined to produce the true filtering distribution in the large particle number limit, and some are uncontrolled, such as ensemble Kalman filter methods which do not recover the true filtering distribution in the large ensemble limit. Other data assimilation algorithms, such as cycled 3 DVAR methods, may be thought of as controlled estimators of the state, in the small observational noise scenario, but are also uncontrolled in general in relation to the true filtering distribution. For particle filters and ensemble Kalman filters it is of practical importance to understand how and why data assimilation methods can be effective when used with a fixed small number of particles, since for many large-scale applications it is not practical to deploy algorithms close to the large particle limit asymptotic. In this paper, the authors address this question for particle filters and,in particular, study their accuracy(in the small noise limit) and ergodicity(for noisy signal and observation) without appealing to the large particle number limit. The authors first overview the accuracy and minorization properties for the true filtering distribution,working in the setting of conditional Gaussianity for the dynamics-observation model. They then show that these properties are inherited by optimal particle filters for any fixed number of particles, and use the minorization to establish ergodicity of the filters. For completeness we also prove large particle number consistency results for the optimal particle filters, by writing the update equations for the underlying distributions as recursions. In addition to loo

关键词： Particle filters Data assimilation Ergodic theory

Parametric analysis of steel plated shear structures

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Journal of Central South University 2014年第5期21卷 2083-2090页

作者： m.Ghassemieh N.Heidari School of Civil Engineering University of Tehran

Due to outstanding ductility and high strength,the steel plate shear wall(SPSW)is recognized as a good lateral system for building structures; particularly as it interacts with earthquake resistant *** study aims to reveal the dynamic and cyclic behavior of steel plated shear *** element method of analysis was implemented in order to simulate the behavior of such a wall *** determine the dynamic behavior of un-stiffened plate shear wall,two different analytical models were *** post buckling strength of steel plate subjected to lateral loading was also *** story shear-drift diagrams of steel shear wall system were *** strength and ductility of the system obtained from the analysis were compared with those of steel shear wall tests reported *** pertinent parameters of the steel shear wall system such as plate thickness,column and beam stiffness and the plate aspect ratio were recognized and their effects were *** effect of stiffeners on the behavior of the SPSW was also investigated.

关键词： steel shear wall pushover analysis energy dissipation ductility post buckling behavior Strut element

The Sendai Framework for Disaster Risk Reduction and Persons with Disabilities

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International Journal of Disaster Risk Science 2015年第2期6卷 140-149页

作者： Laura m.Stough Donghyun Kang Department of Educational Psychology Center on Disability and Development Texas A&M University College Station

In this paper, the Sendai Framework for Disaster Risk Reduction 2015–2030(SFDRR) is evaluated with respect to its ramifications for persons with disabilities. In the SFDRR, persons with disabilities were referenced either directly or indirectly as part of the preamble,the guiding principles, the priorities for action, and the role of stakeholders. In addition, the 2015 World Conference on Disaster Risk Reduction, during which the SFDRR was adopted, incorporated explicit recommendations toward a disability-accessible and inclusive environment not evident in previous disaster risk reduction conferences. The infusion of disability-related terms and concepts such as accessibility, inclusion, and universal design throughout the SFDRR document was significant. These concepts,which have their origin in disability studies, are used in the SFDRR document to refer to the needs of all in disaster,not only to people with disabilities. These disability-related concepts will now serve the field of disaster risk reduction as important overarching disaster-related principles. The authors conclude that the SFDRR has firmly established people with disabilities and their advocacy organizations as legitimate stakeholders and actors in the design and implementation of international disaster risk reduction policies.

关键词： Disabilities International policy Sendai framework for disaster risk reduction World conference on disaster risk reduction

The Thermodynamical Behaviors of Kerr–Newman AdS Black Holes

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Chinese Physics Letters 2013年第9期30卷 29-33页

作者： A.Belhaj m.Chabab H.El moumni L.medari m.B.Sedra Département de Physique FacultéPolydisciplinaireUniversitéSultan Moulay SlimaneBéni MellalMorocco High Energy Physics and Astrophysics Laboratory FSSMCadi Ayyad UniversityMarrakeshMorocco UniversitéIbn Tofail Facultédes SciencesDépartement de PhysiqueLHESIRKénitraMorocco

We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four *** study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a,relating the mass m of the black hole and its angular momentum J via the relation a=J/***,we discuss such thermodynamical behaviors in the presence of a positive cosmological constant considered as a thermodynamic pressure and its conjugate quantity as a thermodynamic *** equation of state for a charged Reissner—Nordstrom AdS black hole predicts a critical universal number depending on the(Q,a)moduli *** the vanishing limit of the a parameter,this prediction recovers the usual universal number in four ***,we find the bounded region of the moduli space allowing the consistency of the model with real thermodynamical variables.

关键词： Newman thermodynamic behaviors

Niche segregation, competition, and urbanization

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Current Zoology 2018年第2期64卷 145-152页

作者： Anders PAPE mФLLER mario DiAz Ecologie Systematique Evolution CNRS Universite Paris-Sud AgroParisTech Universite Pari-Saclay OrsayCedex F-91400 France Department of Biogeography and Global Change (BGC-mNCN-CSIC) NationalMuseum of Natural Sciences CSIC c/Serrano 155bis Madrid E-28006 Spain

Urbanization of species is an ongoing process where successful urban colonizers usually obtain large fitness benefits. mechanisms proposed to explain associations between urbanization and lifehistory traits are based on behavioral flexibility in food and habitat use and reduced fear responses. We test the novel hypothesis that interspecific competition for proximity to humans is driving ur- banization. We recorded the distance during the breeding season to human habitation for 50 pairs of closely related bird species, where one was closely associated with humans while the other species was not. The degree of urbanization was larger as was range size and abundance in the species more closely associated to humans. Flight initiation distance was shorter, and species closely associated with humans were more abundant in ancestral rural habitats. Likewise, species more closely associated with humans reproduced earlier and during longer periods. These results are consistent with the hypothesis that urbanization is promoted by interspecific competition. Resulting isolation by urban habitat may further facilitate contemporary adaptation to urban environments.

关键词： birds distance to human habitation isolation by habitat isolation by time mechanisms.

A Progressive Deployment Strategy for Cooperative Adaptive Cruise Control to Improve Trafc Dynamics

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International Journal of Automation and computing 2014年第1期11卷 10-18页

作者： Georges m.Arnaout Shannon Bowling Department of Engineering management and Systems Engineering Old Dominion University Department of Electrical Engineering Technology Bluefeld State College

Cooperative adaptive cruise control(CACC)vehicles are intelligent vehicles that use vehicular ad hoc networks(VANETs)to share trafc information in real *** studies have shown that CACC could have an impact on increasing highway capacities at high market *** reaching a high CACC market penetration level is not occurring in the near future,this study presents a progressive deployment approach that demonstrates to have a great potential of reducing trafc congestions at low CACC penetration *** a previously developed microscopic trafc simulation model of a freeway with an on-ramp—created to induce perturbations and trigger stop-and-go trafc,the CACC system s efect on the trafc performance is *** results show signifcance and indicate the potential of CACC systems to improve trafc characteristics which can be used to reduce trafc *** study shows that the impact of CACC is positive and not only limited to a high market *** giving CACC vehicles priority access to high-occupancy vehicle(HOV)lanes,the highway capacity could be signifcantly improved with a CACC penetration as low as 20%.

关键词： Intelligent transportation systems telematics vehicular adhoc networks cooperative adaptive cruise control trafc simulation agent-based trafc simulation

Non-uniform slot suction/injection into mixed convection boundary layer flow over vertical cone

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Applied mathematics and mechanics(English Edition) 2013年第11期34卷 1327-1338页

作者： R. RAVINDRAN m. GANAPATHIRAO Department of mathematics National Institute of Technology

The aim of this work is to study the effect of non-uniform single and double slot suction/injection into a steady mixed convection boundary layer flow over a vertical cone, while the axis of the cone is inline with the flow. The governing boundary layer equations are transformed into a non-dimensional form by a group of non-similar trans- formations. The resulting coupled non-linear partial differential equations are solved nu- merically by employing the quasi-linearization technique and an implicit finite-difference scheme. Numerical computations are performed for different values of the dimensionless parameters to display the velocity and temperature profiles graphically. Also, numerical results are presented for the skin friction and heat transfer coefficients. Results indicate that the skin friction and heat transfer coefficients increase with non-uniform slot suction, but the effect of non-uniform slot injection is just opposite.

关键词： mixed convection surface mass transfer non-uniform slot suction singleand double slot vertical cone

Performance,emissions and exergy analyses of adding CNTs to various biodiesel feedstocks

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Propulsion and Power Research 2022年第4期11卷 511-526页

作者： m.S.Gad mostafa m.Abdel Aziz Hatem Kayed mechanical Engineering Department Faculty of EngineeringFayoum UniversityEgypt mechanical Engineering Department Institute of Aviation Engineering and TechnologyGizaEgypt mechanical Power Engineering Department Faculty of EngineeringCairo University12613Egypt

Extraction of biodiesel from waste cooking oil,jatropha,and corn oils is done by *** and biodiesel were blended at 20%volume ratio to make methyl *** doses of 25,50,and 100 mg/l,carbon nanotubes(CNTs)was mixed with biodiesel *** objective of the present research is to examine experimentally a diesel engine performance,combustion characteristics,exergy and emissions analyses with inclusion of nano additive to various methyl ester *** ester blend is enriched with CNTs as JB20C100,WB20C100 and CB20C100 where the improvements in thermal efficiency are raised about biodiesel mixture by 9%,13%and 15%,*** of 100 ppm of CNTs to biodiesel blends achieves the greatest reductions in CO(14%,22%and 30%),HC(16%,20%and 25%),and smoke emissions(15%,19%and 23%)for JB20C100,WB20C100 and CB20C100,*** comparing with B20,blending 100 ppm CNTs with JB20,CB20,and WB20 obtained the highest increases in cylinder pressure of 3%,5%,and 10%,as well as the highest increases in heat release of 4%,7%,and 11%,*** downside of CNTs addition achieves a rise in NOx emissions by 10%,17%,and 22%for JB20C100,WB20C100,and CB20C100,*** efficiency increases by 8%,19%,and 24%for B20T100,B20A100,and B20C100,*** index improvements achieve 1.5%,5%and 6.5%,for B20T100,B20A100,and B20C100,***20 with CNTs of 100 ppm is highly recommended for improving engine performance,combustion,and exergy characteristics with considerable emissions reduction.

关键词： Biodiesel Carbon nanotubes(CNTs) Engine performance Exergy Combustion characteristics Emissions