Non-linear kinematic hardening model for multiaxial cyclic plasticity

A model of kinematic work hardening based on Frederick and Armstrong (1966), Phillips and Weng (1975), Chaboche (1979), and Voyiadjis and Basuroychowdhury (1998) is proposed for metal like behavior materials. In this proposed model, ratcheting is taken into account through the observation of the backstress evolution equation, modified by the addition of a new term, . Experimental observations made by Phillips and Lee (1979) showed that the direction of the movement of the center of the yield surface occurs in between the stress rate tensor and the plastic strain rate tensor directions. The new term, added to Chaboche model (1979), will account for these experimental observation. The model is tested for uniaxial monotonic, cyclic loadings, and for ratcheting prediction. The results obtained are analyzed and compared to existing hardening models and experimental results

Principles of Church-State Relationships in the Writings of Ellen G. White

The Topic Since the beginnings of Seventh-day Adventism there have been real or perceived tensions between two contrasting perspectives of church-state relationships: (1) the “eschatological view” that a union of church and state will lead to persecution in the times preceding the second coming of Christ, and (2) the “temporal view” that in order to accomplish its mission in the present, the church needs to work in an independent, but non-conflictual relationship with the state as far as it can do so without violating its primary allegiance to God. The Purpose In order to discover Ellen G. White’s position on the two perspectives, the study analyzed all the writings of Ellen G. White on the topic of church-state relationships, searching for her principles of church-state relationships. Her principles were compared with the views of others during the colonial and early federal periods of American history, and with the historical records of the church-state debate among Adventists until the end of her life. The Sources The search for principles used all relevant published and unpublished writings of Ellen G. White. The studies of the American historical background and the progression of the debate among Adventists used both primary and secondary sources. The Conclusions Ellen White’s principles of church-state relationships grew out of her worldview of a Great Controversy between good and evil. She believed that both church and state had been established by God as separate institutions with distinct purposes for the benefit of humankind. However, in the conflict between good and evil, both church and state are objects of Satan’s attack. According to White, the state has divinely given authority to enforce the last six of the Ten Commandments which define human responsibilities to other humans, and to safeguard the freedom of humans to obey the first four commandments which describe their responsibilities to God. Thus the proper role of government is to protect both the religious and civil liberties of its citizens. Ellen White expected the church to pursue its mission in compliance with the laws of the land, but with nonnegotiable loyalty to God, and that Adventist participation in social and political activism should always be subordinate to the requirements of the church’s mission

Slab-on-girder prestressed concrete bridges: linear and nonlinear finite element analysis and experimental load tests

“A diaphragm is a transverse stiffener, which is placed between girders in order to maintain section geometry”, (AASHTO, 2002). Intermediate diaphragms, usually placed at the midspan or third points of a bridge, are thought to contribute to the overall distribution of live loads in bridges. Cast-in-place concrete intermediate diaphragms were investigated in this study in order to assess their load distribution effectiveness in prestressed concrete I-girder bridges. Finite element packages (Ansys and GT STRUDL) were used to perform the analyses for multiple bridge configurations, including a parametric study of span length, girder spacing, and concrete strength. It was found that intermediate diaphragms do not contribute significantly to live load distribution and that they are not needed if there is no possibility of impact by an over-height truck. If the risk of a lateral collision to the girders is present, intermediate diaphragms should be placed over the respective traffic lane so that the potential impact takes place at the diaphragms location. Temporary steel diaphragms can be used to stabilize girders during construction. Static and Dynamic live load tests were performed and experimental results were compared to the finite element analysis. Various pavement roughnesses were simulated with the use of wood boards up to 1.5” in depth. A dump truck, driven at 30 MPH, 38.5 MPH and 40 MPH, produced strains and deflections which were processed for load distribution and dynamic allowance (IM) factors. According to the results obtained, there is a more uniform live load distribution as the speed and roughness increase. However, driving at 40 MPH over the 1.5” wood board produced an impact factor almost twice as large as the one specified by AASHTO LRFD (2004). Finally, nonlinear analyses of the tested bridge were performed in order to predict its ultimate capacity. Two bridge configurations were analyzed. The first one was modeled without any diaphragms or edge stiffeners, while the second one with end diaphragms and edge stiffeners. Ultimate loading results show that AASHTO LRFD presents conservative values

Non-reciprocal magnons in a two dimensional crystal with off-plane magnetization

Nonreciprocal spin waves have a chiral asymmetry so that their energy is different for two opposite wave vectors. They are found in atomically thin ferromagnetic overlayers with in-plane magnetization and are linked to the antisymmetric Dzyaloshinskii-Moriya surface exchange. We use an itinerant fermion theory based on first-principles calculations to predict that nonreciprocal magnons can occur in Fe3GeTe2, the first stand-alone metallic two-dimensional crystal with out-of-plane magnetization. We find that both the energy and lifetime of magnons are nonreciprocal, and we predict that acoustic magnons can have lifetimes up to hundreds of picoseconds, orders of magnitude larger than in other conducting magnets.- N.M.R.P. acknowledges support from the European Commission through the project Graphene-Driven Revolutions in ICT and Beyond (Ref. No. 881603 -Core 3), and the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Financing UID/FIS/04650/2013, COMPETE2020, PORTUGAL2020, FEDER, and the Portuguese Foundation for Science and Technology (FCT) through Projects No. PTDC/FISNAN/3668/2013 and No. POCI-01-0145-FEDER-028114. J.F.-R. acknowledges financial support from FCT for Project No. UTAP-EXPL/NTec/0046/2017, as well as Generalitat Valenciana funding Prometeo2017/139 and MINECO-Spain (Grant No. MAT2016-78625-C2). A.T.C. acknowledges the use of computer resources at MareNostrum and technical support provided by the Barcelona Supercomputing Center (RES-FI-2019-2-0034, RES-FI-2019-3-0019)