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[en] The structure of RT room is consist of concrete. Because of low cost and shielding efficiency, the concrete is used widely for building of RT room. But in fortunately, gamma radiation is scattered so much with the concrete and back scattering also very strong. The secondary radiation by back scattering will be big affected in making film image quality in case of heavy wall casting, it is needed long exposure time. The long exposure time means increasing of scattered radiation to the film. In the topic, the interaction of gamma radiation and materials by scattered radiation will discussed and also the attenuation of scattered radiation with concrete. It is the main object to find the method of minimizing the effects by the scattered radiation for each materials and its application.
[en] In order to produce only a pH-controlled solution without discharging any unused solution, has developed a continuous electrolytic system with a pH-adjustment reservoir being placed before an ion exchange membrane-equipped electrolyzer, where as a target solution was fed into the pH-adjustment reservoir, some portion of the solution in the pH-adjustment reservoir was circulated through the cathodic or anodic chamber of the depending on the type of the ion exchange membrane used, and some other the solution in the pH-adjustment reservoir was discharged from the electrolytic system through other counter chamber with its pH being controlled as acid or base. The of the pH being controlled in the system could be explained by the electro-migration of the ion species in the solution through the ion exchange membrane under a cell potential difference between anode and cathode and its consequently-occurring non-charge equilibriums and electrolytic water- split reactions in the anodic and cathodic chambers
[en] A Failure that happened sometimes ago in the sintering furnace of HR-05 PEBN-BATAN became a driving force of the investigation to find out the reason of the failure and to review its safety system. From the component level analysis of its electrical system, it is concluded that the failure is caused by the gas trapped inside the furnace while its heating system is on and gas outlet is closed, so that a small explosion is occurred to break the filament heater of the furnace. The failure of the outlet to open is caused by the weakness of the triggering instrument to the outlet while the explosion is caused by the weakness of the safety system design. The replacement of the triggering instrument according to the improved design is the best solution. However, an alternative solution is given if it is desired to keep the old triggering instrument still working in the system after being repaired. (author)
[en] One of the important tasks in the design activities is to accurately predict the pressure losses and flow distribution in the reactor. This task can be challenging especially when facing configurations with no empirical correlations available in the literature. An example of such challenges encountered in the design activity is a region in the flow path which undergoes a sudden contraction followed by a double expansion. In this paper, with the aim of estimating the appropriate orifice size corresponding to the targeted pressure drop, the flow in the above mentioned region is investigated numerically and representative results are presented. In this work, CFD analyses were conducted to develop a correlation for pressure loss coefficient for fluid experiencing a sudden contraction followed by two expansions. Sensitivity tests were also conducted to identify the proper turbulence model and to achieve a grid independent solution.
[en] Amphiphilic molecules (surfactants) consist of two opposing parts - a water-soluble moiety and a water-insoluble one - which are chemically bonded. Consequently, above a certain threshold concentration in aqueous solution (critical micellar concentration, cmc) surfactants self-assemble into aggregates. Aqueous solutions containing linear, flexible chain molecules (polymers) and surfactants exhibit self-assembly at much lower surfactant concentrations. This feature offers a delicate control over the physical properties of the solution, which is used in numerous applications. We study theoretically the onset of self-assembly in such polymer-surfactant systems. Focusing on the effect of the surfactant on polymer conformation and using a conjecture of local instability of the polymer at the onset of self-assembly, we obtain several simple predictions: (i) the threshold concentration required for polymer-surfactant self-assembly (critical aggregation concentration, cac) is always lower than the cmc; (ii) in charged systems the cac increases with the concentration of added salt and is almost independent of polymer charge; (iii) in weakly interacting systems the cac follows changes in the cmc roughly linearly. We further use the special case of interactions between surfactants and amphiphilic polymers to demonstrate the crucial role of chain conformation in the self-assembly. The predictions are supported by available experiments
[en] The paper shows two possibilities obtain first systems of solid phase in the case of growing single-crystals from solutions. These systems, obtained from a supersaturated solution or by a preferential cutting from a single-crystal previously grown, are thermodynamically stable and were used as seeds for further growing under controlled conditions. The paper also mentioned the method used for the growing Kdp single-crystals from solution, the slow cooling method, using seeds obtained by the help of the two methods previously mentioned. In addition, the paper shows two Kdp single-crystals grown from the liquid phase from the two types of seeds