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Deterioration Characteristics of Bridges in Various Districts of Fukui Prefecture
No full textThe deterioration characteristics of bridges have been clarified with progress of inspection of bridges in Fukui prefecture. In this study, the deterioration transfer curve of each member element of bridges in Sabae, Ono, Katsuyama, Fukui and Obama cities isintroduced to compare the deterioration characteristics. The differences of characteristics are discussed for each bridge type. It is emphasized that the deterioration transfer curves of bridges should be introduced in each district considering the environmental difference. Furthermore, the causes of deteriorations for each member element are detected by classifying 4156 numbers of damages in bridge
Fundamental Study of Magnetic Separation Method for Radioactive Contaminant
No full textSince the accident that happened in The Fukushima Daiichi Nuclear Power Station, a scattered radiological decontamination and decommissioning technology are attracting a lot of attention. The removal of radioactive crud in the nuclear power plant will become one of the more important elemental technologies of the decommissioning from now on. However, the effective technique to remove the crud which is applicable at high-temperature area around the nuclear power plant does not exist. Therefore, we focused on the magnetic property of the target cruds which are paramagnetic substance and high gradient magnetic separation (HGMS) was proposed as a nuclear power plant crud removal method. In this study, we tested the magnetic separation of crud sample model in room temperature for the practical use of the HGMS device and a possibility of the application of our method was indicated
An Attempt to Improve the Measurement Precision in Tungsten-Filament Electrothermal Vaporization / ICP-Mass Spectrometry for the Determination of Trace Phosphor
No full textIn order to improve the measurement precision in tungsten-filament electrothermal vaporization (WF-ETV) / inductively coupled plasma mass spectrometry (ICP-MS) for the determination of trace phosphor, we attempted the application of an internal standard method. The delay time between the discharge of a capacitor in the WF-ETV system and the start of measurement in ICP-MS was optimized for the simultaneous measurement of several elements. Operating parameters for WF-ETV were investigated to obtain appropriate intensities of phosphor, and consequently the optimum values of electric
current for desolvation and sample volume became 3.3 A and 3.0 L, respectively. While relative standard deviation (RSD) of intensities of phosphor more than 50% was improved to 17% by correcting with those of cobalt as an internal standard element, the improved RSD was almost the same as the value obtained before. It was found that more detailed studies for selecting suitable internal standard elements were needed to improve the reproducibility of WF-ETV / ICP-MS
Decrease in the double layer capacitance by faradaic current
No full textThis study describes the reverse of the well-known double layer effects on charge transfer kinetics in the relationship between a cause and an effect. The reversible redox reaction of a ferrocenyl derivative decreased the capacitive values of the double layer impedance up to negative values, corresponding to an inductive component. This observation was disclosed by the subtraction of the real admittance from the imaginary admittance, which can extract the net double layer capacitance from the Warburg impedance. The inductance-like behavior is caused due to two reasons: (i) the double layer capacitance in the polarized potential domain is determined by the low concentrations of the fieldoriented solvent dipoles that are considered as the conventionally employed redox concentrations and (ii) the double layer capacitance is caused by the orientation of the dipoles in the same direction as that of the electric field, whereas the redox reaction generates charge in the direction opposite to the field. The faradaic effect was demonstrated via the ac-impedance data obtained for the ferrocenyl compound in a KCl solution in the unpolarized potential domain between 1 Hz and 3 kHz frequency. The negative admittance was proportional to the frequency. The theory of negative capacitance was presented by combining the mirror-image surface charge with the Nernst equation
Study of Direct Heating Defrost for Plate-finned Tube Heat Exchanger with an Induction Heating
No full textThe defrost system with the induction heating have been proposed to be applied to the air conditioner. This induction heating system is made of a swirled coil and a high frequency inverter, when this coil is conducted 30kHz AC current, the plate finned tube type heat exchanger was heated by the electro and magnet phenomena. From the practical point of this defrost system, at first, the analysis of the pressure drop of coil and heat exchanger was conducted to evaluate, secondary, the measurement of impedance and the induction heating defrost test were conducted to investigate the heating efficiency and the defrost time. Thus, it is found that the heat exchanger was uniformly heated and the frost of 170g on the surface of that were melted by the induction heating for 30 min. From these fact, the validity of the proposed system was verified
Effects on Operation Characteristics of Exhaust Gas Recirculation of Diesel Engines Using Bio Fuel
No full textBio Diesel Fuel (BDF) contains a lot of oxygen, but the ignitability is inferior because of its high viscosity compared with gas oil. Previous research has shown that the combustion status of BDF has been improved through increased net thermal efficiency with a larger fuel supply. However, the NOX density in the exhaust gas increased in that case as well with the rise of combustion temperature. In this study, effective EGR for NOX decrease is applied and the effect on operation characteristics of the engine is investigated. In particular, the expected increase in PM emissions due to the lower excess air factor is compared with that when using gas oil. The results make it clear that superior operating characteristics during BDF use can be obtained in comparison to the use of gas oil, in operating conditions with a decreased excess air factor
