Handy X-ray fluorescence (XRF) spectrometers are reviewed. A brief history of development, comparison with desk top or larger XRF spectrometers, and analyzed data examples are described. The usages of handy spectrometers related to recycling of metal scrap, control of hazardous elements in industrial products, toxic element analysis of soil at the trading of immovables, and developing a mine of rare metals, are discussed. The total number of portable XRF has been over 45000 all aver the world at the stage of year 2010.
Atmospheric corrosion of the steel surface of a bridge is largely due to salt spays generated over the ocean and transported around the bridge. The observed data indicate that the salt sprays first adhere to the steel, after which the extent of Cl− on the steel surface increases; however, the mechanism by which these processes occur has not yet been investigated. Our research objectives are to examine the relationship of atmospheric Cl− concentration with the extent of Cl− adhering to the steel surface and to clarify the effect of surface winds on the extent of Cl− adhesion. The results show that the extent of Cl− adhesion is positively correlated with atmospheric Cl− concentration and that the extent of Cl− adhesion depends on surface winds. Therefore, when estimating Cl− on a steel surface, we must consider the atmospheric Cl− concentration and the surface winds.
On the cathodic protection system for concrete structure, a galvanic anode system is recently highlighted as maintenance-free system. But, only some reports on the periodic or continuous monitoring of its performance can be found. The report covers the continuous monitoring of the performance on our galvanic anode system with “aluminum panel anodes”, applied to the concrete highway bridge. The external view on the bridge was kept in initial condition for eight months after application. Although more positive ON potential of the rebar and lower output current of anode per unit rebar surface area were observed at lower ambient temperature, the rebar potential was kept in sufficient protection level.
This paper reports a new approach for the modeling of SCC crack growth in nuclear coolant environments. Many SCC tests have been carried out since 70’s. Some of crack growth rate data was observed to be widely scattered. Previous studies have concentrated on the prediction of crack growth rate in a wide range of stress intensity factor. On the review of many laboratory test data, we propose a process of crack growth of SCC is the coupled phenomenon as a result of synergistic state transition between mechanical system that consisted of stress and material, and chemical system that consisted of material and environment. The coupled phenomenon is a two-stage reaction as results of state transitions of material which commonly exists in the both systems. Since in the case of new approach, several critical reactions could exist in the process of SCC crack growth, it could be explained that an observed data in laboratory test was fluctuated.
The purpose of this research is to basically investigate a corrosion protection method by sacrificial anode applying to steel members in atmospheric environment. In this method, porous sintered Al-Zn plate was applied as sacrificial anode materials. In addition to this, cross-linking chemical fiber sheet was also applied as the material which has functions of continual water absorption and retention needed for sacrificial anode reaction. In order to investigate the anticorrosive effects, electro-chemical measurements of current, potential and corrosion protection effective range of corrosion protection were carried out. Moreover, atmospheric exposure tests were conducted with specimen consisted of steel, fiber sheet and porous sintered Al-Zn plate. The measurements results showed that the effectiveness of the corrosion protection method was confirmed.
Chemical reactions between metal and nitrate ion have been studied to determine their roles in chemical conditioning of a radioactive waste disposal repository and its surrounding environment. Immersion tests and rest potential measurements under hyper-alkaline and high NaNO3 concentration conditions were conducted to elucidate and improve model predictions of chemical interactions between carbon steel and NO3− in highly concentrated solutions of nitrate salts. Potentiostatic electrolysis experiments in the concentrated solution with a carbon steel electrode, as the working electrode, were also conducted to determine the electrochemical rate equation for NO3− reduction to NO2−. Experimental results of potentiostatic electrolysis of the concentrated solutions showed that a linear electrochemical rate equation for NO3− reduction to NO2−, as used in the previous model, gave too high a rate under the conditions of high NaNO3 concentration (≧1 mol dm−3). To ameliorate this effct, a non-linear equation was derived assuming a Langmuir type adsorption process of NO3− as a precursor process of discharge, and the parameter for the equation was determined by curve fitting using the data acquired under the conditions of potential −0.85 V vs. SHE and pH 12.5. The equation was incorporated in the model, and was used to analyze the results of ampul tests and rest potential measurements. The modified model can estimate the tendency of time dependent variation of chemical species and of rest potentials in the highly concentrated solution of NaNO3.