Papers by Keyword: Grains

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Authors: Hong Wei Wang, Qi Jun Li, Zhan Hou Wang
Abstract: This paper provides an automatic barn-entering system for grains. Based on the technologies of microwave and PLC, the system may detect the grain moisture on line and control the directions of grain flows on conveyor. For the flows with moisture below the specified threshold, the grains may be made their way into the barn, otherwise rechannel the direction automatically and not permitted into the barn.Thus can avoid effectively grains' from going mouldy due to the high moisture content.
Authors: Nudrat Humera, Hadia Noor, Saira Riaz, Shahzad Naseem
Abstract: Barium titanate (BTO) samples were prepared by nanomilling based solid state reaction method. Dielectric behavior of BTO sample has been investigated by temperature dependent impedance spectroscopy. The impedance analysis of BTO samples confirm that hopping of electrons and defects coexisted in sample and contribution of grain and grain boundary to dielectric behavior is discussed. A single semicircular arc obtained by Nyquist plots whose radius decreased with increase in temperature illustrates the prominent role of grains. The activation energy of defects was calculated from Arrhenius plot. These defects may be due to oxygen vacancies and hopping between Ti+4 to Ti+3 ions.
Authors: Jong Bong Kim, Jeong Whan Yoon
Abstract: Without initial imperfection and damage evolution model, it is difficult to analyze the necking behavior by finite element analysis with continuum theory. Moreover, the results are greatly dependent on the size of the initial imperfection. In order to predict necking phenomenon without geometric imperfection, in this study, a crystal plasticity model was introduced in the 3-dimensional finite element analysis of tensile test. Grains were modeled by an octahedron and different orientations were allocated to each grain. Damage model was also used to predict the sudden drop of load carrying capacity after necking and to reflect the void nucleation and growth on the severely deformed region. Well-known Cockcroft-Latham damage model was used. Void nucleation, growth and coalescence behavior during necking were predicted reasonably.
Authors: E.G. Bennett, L.J.M.G. Dortmans, M. Hendrix, Roger Morrell, G. de With
Authors: B. Škipina, T. Čajkovski, M. Davidović, D. Čajkovski, V. Likar-Smiljanić, U.B. Mioč
Abstract: In our previous work we investigated the conductivity and dielectric relaxation phenomena in heteropoly acids and their salts. In this work, we have studied the conductivity of grains and grain boundaries in compressed powders of 12-tungstophosphoric acid (WPA) salts with univalent and bivalent ions. The method of impedance spectroscopy has been employed in the frequency range from 5 Hz to 500 kHz. We obtained grains and grain boundaries conductivities as well as corresponding activation energies. Grain conductivity in all investigated salts is always higher than the grain boundary conductivity.
Authors: Zakaria Boumerzoug, Lakhdar Lakhdari
Abstract: In this work, the effect of isothermal heat treatments on microstructure evolution and mechanical properties after welding by induction of A37 pipeline steel have been studied by scanning electron microscopy, hardness measurements, and tensile tests. Microstructural evolution in welded joint was identified after isothermal annealing from 200 until 900 °C.
Authors: Sparisoma Viridi, Siti Nurul Khotimah, Novitrian, Widayani
Abstract: Probability occurrence between two successive 2-d granular materials configuration, which are related to their entropy, can be used to check history line of the materials configurations. As an example, a well-known Brazil-nut effect will be presented. In small region it seems that this effect violates principle of minimum energy but not as the whole system, where the energy does decrease. In this work effect of temperature is considered constant since the configurations are observed in frozen states instead of dynamic or fluidized states.
Authors: G.K. Sfantos, Ferri M.H.Aliabadi
Abstract: In this paper, intergranular microfracture evolution in polycrystalline brittle materials is simulated using a cohesive grain boundary integral formulation. A linear cohesive law is used for modelling multiple microcracking initiation and propagation under mixed mode failure conditions, encountering the stochastic e=ects of the grain location, morphology and orientation. Furthermore, in cases where crack surfaces come into contact, slide or separate, fully frictional contact analysis is performed.
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