HVEM study of crack-tip dislocations in Si crystals prepared by FIB and twin-blade cutting method

Crack-tip dislocations in silicon crystals have been examined by using high-voltage electron microscopy. Cracks were introduced by the Vickers indentation method at room temperature and the indented specimens were annealed at high temperatures to induce dislocations around crack tips under the presence of residual stress due to the indentation. A selected area around a crack tip was thinned by a focused ion beam (FIB) technique. Specimens were thinned in advance by a twin-blade cutting (TBC) method, which is a simple cutting process for saving FIB machine time. A combination of FIB and TBC can be a useful thinning procedure for the efficient preparation of transmission electron microscopy specimens. Characteristic dislocation structures were observed around the tip of a crack, aiding the elucidation of dislocation processes, which is essential to increase the fracture toughness of materials.     

Experimental study of several types of ground heat exchanger using a steel pile foundation

An experimental study of several types of ground heat exchangers (GHEs) installed in a steel pile foundation, including double-tube, U-tube, and multi-tube GHEs, was carried out at Saga University. Water flows through the heat exchangers and exchanges heat to or from the ground. The performance of GHEs was investigated under actual operation in the cooling mode with flow rates of 2, 4, and 8 l/min. Temperatures of the ground and GHE tube wall were measured to find the temperature distributions according to the depth of the ground and depth of the GHE tube wall. The temperatures of the inlet and outlet of circulated water were also measured to calculate the heat exchange rate. The double-tube had the highest heat exchange rate, followed by the multi-tube and U-tube GHEs. For example, the average heat exchange rate of GHEs over 24 h of continuous operation with a flow rate of 4 l/min was 49.6 W/m for the double-tube, 34.8 W/m for the multi-tube, and 30.4 W/m for the U-tube. An increasing flow rate increased the heat exchange rate of the GHEs. The heat exchange rates increased significantly for flow rate increases from 2 to 4 l/min, but only slightly changed from 4 to 8 l/min.     

Production of High Fructose Syrup by Glucose Isomerase Immobilized on Phenol-Formaldehyde Resin

An immobilized glucose isomerase which is active and stable in concentrated glucose solution has been developed. The enzyme has been immobilized to Duolite A7 resin simply by adsorption. Industrial application of this immobilized enzyme for the continuous production of high fructose syrup is quite promising because the immobilized enzyme having enough mechanical strength against the pressure of column flow, is active over broad ranges of both temperature and pH and is less dependent on Mg and Coions. Long-run continuous experiments in column system have been carried out, isomerizing 45% of glucose with flow rate of SV 1 at 60°C. A gradual decrease of activity was observed after 25 d operation and the half-life was calculated to be 36 d. One liter of the immobilized enzyme in column isomerized 288 kg of glucose in a month. The values of kinetic parameters of the immobilized enzyme in column operation varied with flow rates and approached to those of the native enzyme when they were assayed at the flow rate approaching to SV 0.     

Dissemination of the Japanese version of the International Chemical Safety Card (ICSC) on the World Wide Web (WWW)

ge of the Japanese version of the International Chemical Safety Cards (ICSC). We prepared the Japanese text files of ICSC, converted them into HTML files and also prepared the dictionary database for the retrieval system, using programs which we developed. These programs shortened the time of work remarkably. 2D- and 3D-structures of chemicals were also incorporated in each ICSC page. Approximately 900 ICSCs in Japanese are provided at the moment on the homepage.     

An investigation of the age hardening behavior of PM 2024Al-Fe-Ni alloys and the effect of consolidation conditions

The aging ability of two PM alloys based on 2024Al with Fe and Ni addition has been investigated by means of EDX, XRD, DSC, TEM and Vickers hardness analysis, and compared with that of the base alloy PM 2024 aluminum. Effect of consolidation temperature and powder size on the aging behavior of the 3F5N alloy was also studied. The results showed that the 3F0N alloy, PM 2024Al with 3 mass% Fe single addition, exhibited poor aging ability compared to 2024 alloy. In this alloy, the amount of solid solution Cu was found to decrease by forming Al₇Cu₂Fe compound during solidification, resulting in a lower amount of Cu dissolved into the α-Al matrix of the extrusions during the solution treatment. Whereas the 3F5N alloy, PM 2024Al with a 3 mass% Fe and 5 mass% Ni combined addition, showed almost the same age hardenability compared to PM 2024 alloy. Due to the addition of Ni, the amount of insoluble compound Al₇Cu₂Fe was decreased by the formation of Al₉FeNi phase in the 3F5N alloy. Thus, more Cu could be dissolved into the matrix during the solution treatment. A quantity of GPB zone could be formed in the 3F5N alloy during the aging resulting in higher age hardenability than the 3F0N alloy. The extrusion temperature and powder size were found to affect the aging hardenability of the 3F5N extrusions. Although higher age hardenability could be obtained in the 3F5N specimen extruded from powders with the relatively larger diameter, it was found that with decreasing extrusion temperature the higher aging ability could also be obtained in the 3F5N alloy extruded from finer powders. This revised version was published online in September 2006 with corrections to the Cover Date.     

A method for estimating visceral fat from the elasticity of lumbar subcutaneous fat

Since metabolic syndrome is a cause of lifestyle-related diseases, and its early diagnosis and an evaluation of visceral fat are important, this study proposes a new method of estimating the amount of fat. The goal of this study is to estimate visceral fat from estimation of subcutaneous fat and total fat. The subcutaneous fat is estimated from the elasticity of the lumbar area, and the total fat is estimated from body information such as the abdominal vertical and lateral width, and body weight. Finally, the estimated subcutaneous fat is subtracted from the estimated total fat to calculate the visceral fat. Measurement tests conducted to verify the constructed visceral fat estimation model showed good results, with a correlation of 0.96 between the visceral fat area estimated by the proposed method and the actual measured area. The reproducibility of the estimation model was also verified by the cross validation method.     

Biodiesel fuel production from plant oil catalyzed by Rhizopus oryzae lipase in a water-containing system without an organic solvent

A new enzymatic method of synthesizing methyl esters from plant oil and methanol in a solvent-free reaction system was developed. It is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future. Lipase from Rhizopus oryzae efficiently catalyzed the methanolysis of soybean oil in the presence of 4–30 wt% water in the starting materials; however the lipase was nearly inactive in the absence of water. The methyl ester (ME) content in the reaction mixture reached 80–90 wt% by stepwise additions of methanol to the reaction mixture. The kinetics of the reaction appears to be in accordance with the successive reaction mechanism. That is, the oil is first hydrolyzed to free fatty acids and partial glycerides, and the fatty acids produced are then esterified with methanol. Although R. oryzae lipase is considered to exhibit 1(3)-regiospecificity, a certain amount of 1,3-diglyceride was obtained during the methanolysis and hydrolysis of soybean oil by R. oryzae lipase solution. Therefore, the high ME content in the reaction mixture is probably attributable to the acyl migration from the sn-2 position to the sn-1 or sn-3 position in partial glycerides.