Results 1 - 10 of 482
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[en] For the joints composed of steel beams and reinforced concrete columns, shear failure and bearing failure are the key failure modes. The shear failure indicates stable hysteresis loop without the strength degradation. On the other hand, the bearing failure mode indicates large pinching and strength degration after the attainment of the maximum load. Accordingly, bearing failure in the joints should not be caused in RCS system.To improve the bearing failure behavior of S beam - RC column joint, joint details using perfobond plate connectors were proposed. Perfobond plate connectors were attached on the upper and bottom flanges at right angles to the steel flange. The objective of this study is to clarify the effectiveness of proposed joints details experimentally and theoretically. Six specimens were tested. All specimens were T-shaped planar beam - column joints with 350mm square RC column and S beams with the width of 125mm and the depth of 300mm. The beams were all continuous through the column.Perfobond plate connectors were attached on the bottom flanges at right angles to the steel flange.Three holes were set up in the perfobond plate connectors. The experimental variable was the transverse reinforcement ratio of the joints. The transverse reinforcement ratio of the joints was 0.181% and 0.815%. For each transverse reinforcement ratio of the joints, specimen without the perfobond plate connectors, specimen with the perfobond plate connectors and specimen with the reinforcing bar inserted the hole of perfobond plate connectors were planned. For all specimens, the hysteresis loop showed the reversed S-shape. However, energy dissipation for specimens for specimens with perfobond plate connectors was larger than of specimen without perfobond plate connectors. Bearing strength of specimens with perfobond plate connectors was larger than that of specimen without perfobond plate connectors. From the test results, shear strength of concrete connector a hole was 0.7 times compression strength of concrete.On the other hand, shear strength of inserted reinforcing bar was 1.25 times shear strength of reinforcing bar. Based on the stress transferring mechanism and resistance mechanism of joints proposed by authors, the design formulae of joints with perfobond plate connectors were proposed.The predictions were shown to be in good agreement with the test results. (Author)
[en] Microstructure of as-annealed Laves phase NbCr2 containing 5 at.% V exhibits neither micro twins nor stacking faults, in contrast to binary NbCr2. The stacking fault energy in NbCr2 containing 5 at.% V was evaluated to be approximately 29 mJ m-2. Strain rate dependence of the flow stress and deformed microstructures for NbCr2 containing 5 at.% V at 1623 K suggests that the deformation is controlled by the glide and climb of dislocations (with the Burgers vector of 1/2<011>). No evidence showing the activation of mechanical twinning was obtained. The effect of V addition on microstructures before and after deformation of NbCr2 was discussed from the viewpoint of phase stability of the C15 structure against the C14 structure
[en] A three-dimensional CAD system for plant layout of nuclear power plants has been developed, adopting the latest technologies of knowledge engineering, CAD/CAM, and interactive computer graphics. With this system, Hitachi is now able to plan plant layout more effectively, reduce design time and cost, and detect defective designs before actual construction problems occur. Hitachi is planning to enhance this three-dimensional CAD system to a plant total life computer-aided engineering (CAE) system. This system will include a construction CAE system, a test operation and in-service inspection control system, and a plant maintenance system. After completion of this system, Hitachi will be able to plan, monitor, and control all major aspects in the life of a nuclear power plant from the very first stage of the planning to its decommissioning
[en] A method of making stabilized superconductors of a composition such as Nb3Sn is disclosed. The method includes forming a stock product comprising a tin base alloy as a core with a copper jacket and having a niobium tube clad thereon. The stock product is then embedded in a good thermally and electrically conducting matrix which is then coreduced until the desired size is obtained. This cold worked product is then submitted to a heat treatment to form superconductors of Nb3Sn
[en] The crystallization behaviors of safflower and olive oils were investigated according to changes in volume and transmitted light intensity during isothermal storage at low temperature. The changes between the oils were significantly different even though their fatty acid compositions were similar, with oleic acid accounting for more than 75% (w/w) of the total oil. It was expected that minor components with high melting points would affect the crystallization behaviors of these oils. The crystallization processes of the oils were then analyzed using a kinetic model in which the oil crystallizes through two different processes. It is suggested that although the crystallization behaviors were apparently different, the crystallization mechanisms of these oils are essentially the same.
[es]Se estudiaron los comportamientos durante la cristalización de aceites de cártamo y oliva en función de los cambios en el volumen y la intensidad de la luz transmitida durante el almacenamiento isotérmico a baja temperatura. Los cambios fueron significativamente diferentes entre los dos aceites, aunque su composición en ácidos grasos era similar, con el ácido oleico en una proporción superior al 75% (p/p). Se esperaba que los componentes menores con altos puntos de fusión afectarían a los comportamientos de cristalización de estos aceites. Los procesos de cristalización de los aceites se analizaron utilizando un modelo cinético en el que el aceite cristaliza a través de dos procesos diferentes. Se sugiere que, aunque los comportamientos de cristalización fueron aparentemente diferentes, los mecanismos de cristalización de estos aceites serían esencialmente los mismos.
[en] Construction and maintenance of nuclear power plants have important problems such as shortening the construction period and reducing the construction cost. Recently, the problem of insufficient construction labor has arisen, and as drastic strategic development has become a necessary counter-measure. The following four principles are included in the measures to be taken for efficient execution of the construction work within the short construction period: (1) reduction of on-site work and expansion of module block making, (2)improvement of the accuracy of the on-site work process, adjustment and expansion of the work in parallel with the construction process, (3)improvement of efficiency of the on-site work and mechanization and automation of the work, (4)improvement of the accuracy of the management of the construction. A three dimensional simulation system plant construction plan CAE, comprising five modules has been developed. A project management system was also developed to improve the accuracy and efficiency of management work in the field