Abstract— We present a RGB multicolor EL display, in which a blue organic EL display was combined with color‐changing media (CCM). The CCMs were basically made up of organic fluorescent media which changed the emission color from blue to green or red.
Abstract Zero-dimensional computations of nanosecond-order ignition using a nanosecond discharge are performed with two constraints. The effects of these constraints are assessed to study the experimental rapid pressure change properly at the initial stages. The computations are carried out with the following constraints: constant internal energy and volume (U&V) and constant enthalpy and pressure (H&P), revealing differences between the two solutions. As the pressure remains constant under the H&P constraint, the total number density of all species decreases during ignition. In this case, O radicals are less generated and consumed. The progression of all reactions and temperatures increases under the H&P constraint less intensely than under the U&V constraint. Significant differences are found between the results calculated under the U&V and H&P constraints. Therefore, large discrepancies with real phenomena can be caused if the loss due to pressure reduction is not treated well.
This paper presents an electro-mechanical model for evaluating the corrosion-induced damage in reinforced concrete under accelerated conditions. The model consists of structural analysis of concrete and the rebar using the Rigid Body Spring Method and corrosion current analysis with the truss networks model. The electric corrosion process is coupled with concrete cracking conditions by relating current efficiency to local crack width; the predicted radius losses of rebars are used to evaluate concrete crack propagation and residual tensile performance of corroded rebars. The model is validated with the results of accelerated corrosion tests using impressed current and a sodium chloride pond on the concrete cover. Good agreement with the test data is obtained with the proposed model, in terms of corrosion degree and profile, concrete crack pattern, and tensile behavior of corroded rebars. The model offers a corroborative tool with the accelerated corrosion technique to study the mechanical behavior of corroded concrete structures.
With a focus on crack propagation in concrete, this Committee concentrated on the morphology of cracking and investigated the current state and future development of the evaluation of crack propagation, while inventorying test and analysis techniques currently available and examining their scope and potential. The topics included testing techniques capable of evaluating crack propagation (digital image processing, etc.), analysis techniques for evaluating crack propagation (FEM, RBSM, etc.), and methods of evaluating crack propagation in deterioration cases due to various causes (drying shrinkage cracking, corrosion cracking, etc.).
This paper aims to investigate the individual effect of corrosion‐induced crack, corroded rebar shape, and rust around rebar on the bond properties of reinforced concrete (RC) members. First, test specimens were corroded by accelerated electric corrosion method with varying corrosion degree ranging from 0 to 25%. Test specimens were divided into different groups. For the normal corrosion group, bond test was conducted directly after the corrosion test to investigate the combined effects including corrosion‐induced crack, corroded rebar shape, and rust on bond deterioration. In another group, after corroded rebar was taken out from test specimen, rust was removed before casted into new concrete to evaluate single effect of corroded rebar shape. Similarly, corroded rebar with rust was casted into new concrete to evaluate the effect of the formation of rust on bond degradation. Experimental results quantitatively illustrate the influential factors including corrosion degree, corrosion crack width and geometry of corroded rebar. As the important finding, corrosion crack in concrete is concluded to be a more dominant factor than the corroded rebar shape and rust accumulation in bond deterioration mechanism. Moreover, rust accumulation contributes to the improvement of bond deterioration induced by corroded rebar shape.
The purpose of this paper is to clarify the mechanism of shear strength reduction for reinforced concrete deep beams with varying stirrup ratios, due to the beam size increase. Three Dimensional Rigid-Body-Spring-Method was the applied numerical tool. By using the simulation results of reinforced concrete deep beams with the effective depth smaller than 1500 mm, the size dependence of each shear resistance component such as arch, beam and truss actions were investigated, along with the size dependence of localized information such as crack pattern, diagonal crack width and compressive stress. It was revealed that the size effect on shear strength results from the size dependence of the arch action, and the change of stirrup ratio does not show any inhibiting effects on it. The crucial reason for the size effect on the arch action is the size dependence of concrete compressive resultant on beam cross sections, and the critical diagonal crack width, which increases with beam size, is a key factor for the deterioration of concrete compressive strength and the capacity of compressive stress in struts. Moreover, it was found that the critical diagonal crack width not only affects the normalized shear strength, but also has influence on the post-peak behavior of deep beam.
The behavior of tritium release from the vacuum vessel of JT-60U during air exposure phase at controlled water vapor concentration and gas purging in the wall conditioning phase has been investigated. For the air exposure with varying water vapor concentrations of 40ppm, 300ppm, 680ppm and 3400ppm, tritium concentration in the vacuum vessel of JT-60U was measured. At each water vapor concentration, tritium concentration initially increased with time and then became steady finally. The steady tritium concentration increased with water vapor concentration. The total amount of tritium released from the vacuum vessel was 13MBq for 3400ppm. This amount is almost the same as that removed by 5 hours’ H2-GDC, which has been the most effective method for tritium removal from JT-60U. This suggests that tritium in the vacuum vessel of JT-60U can be easily removed by water vapor. Tritium released into exhaust gas during gas purging was also measured for varying gases (H2, He and Ar), at different pressures and temperatures of the vacuum vessel. Tritium concentration of the exhaust gas was about 0.1Bq/cm3 at room temperature and was independent of gas species within the pressure from 0.05 to 0.3 Pa. This result indicates that isotope exchange of tritium with hydrogen molecules was not so active under these purge conditions.
