Clostridium perfringens in Dehydrated Soups and Sauces

SUMMARY– Fifty-five samples of nationally advertised dehydrated sauce and gravy mixes, soup mixes, spaghetti sauce mixes, and cheese sauce mixes were examined for the presence of Clostridium perfringens. The organism was found in 18.2% of the samples. Spaghetti sauce mixes had the highest incidence of C. perfringens and the soup mixes had the lowest incidence. One strain possessed heat-resistant spores that were able to withstand boiling at 97.4°C for one hour prior to isolation. The presence of preservatives in the food products did not influence the presence of C. perfringens in these food preparations. No common ingredient was detected as the source of contamination. The general presence of this organism in dehydrated soups and sauces may have epidemiological significance in C. perfringens food poisoning, especially since these products are exposed to short besting periods.     

A New Protein Band Appearing in the Electrophoretic Pattern of Egg White Heated at Below 60°C

When egg white was heated to between 50° and 60°C, a new protein band appeared in its polyacrylamide gel electrophoretic pattern. The formation of the protein band in stored egg white was almost the same as that of fresh egg white. This protein band was shown to be induced by the interaction between macroglobulin and lysozyme during the egg white heating. The optimum temperature for its formation was between 54°C and 57°C. This band formation may be used as an indicator for heat treatment of egg white.     

The "Itrinsic" Thermal Conductivity of Wet Soy Protein and Its Use in Predicting the Effective Thermal Conductivity of Soybean Curd

The applicability of four heat conduction models to heterogeneous materials was examined for defatted soy protein curd with various water contents. Only the series model was applicable to both frozen and unfrozen soy protein curds. The “intrinsic” thermal conductivity of wet soy protein was determined on the basis of the series model to be 0.300 W/m·K for unfrozen curd and 0.488 W/m·K for frozen curd. By using the series model and the “intrinsic” thermal conductivity values of soy protein, the effective thermal conductivity of fat-containing soybean curd, unfrozen or frozen, was predicted satisfactorily. The “intrinsic” thermal conductivity values of wet soy protein were independent of temperature in the ranges from 0° to 20°C and from ?5° to ?20°C.     

Empirical correlations for predicting the self-leveling behavior of debris bed

Studies on the self-leveling behavior of debris bed are crucial for the assessment of core-disruptive accident (CDA) occurred in sodium-cooled fast reactors (SFR). To clarify this behavior over a comparatively wider range of gas velocities, a series of experiments were performed by injecting nitrogen gas uniformly from a pool bottom. Current experiments were conducted in a cylindrical tank, in which water, nitrogen gas and different kinds of solid particles, simulate the coolant, vapor (generated by coolant boiling) and fuel debris, respectively. Based on the quantitative data obtained (mainly the time variation of bed inclination angle), with the help of dimensional analysis technique, a set of empirical correlations to predict the self-leveling development depending on particle size, particle density and gas injection velocity was proposed and discussed. It was seen that good agreement could be obtained between the calculated and experimental values. Rationality of the correlations was further confirmed through detailed analyses of the effects of experimental parameters such as particle size, particle density, gas flow rate and boiling mode. In order to facilitate future analyses and simulations of CDAs in SFRs, the obtained results in this work will be utilized for the validations of an advanced fast reactor safety analysis code.     

Voltage Regulation Utilizing Electric Vehicle Rapid Chargers in a Distribution System

From growing interests in the environment issues, promotion of photovoltaic power generation (PV) is accelerated in the world. Meanwhile, rapid chargers (RCs) for popularized electric vehicles are being installed in urban areas. These two trends in distribution system might cause severer voltage fluctuation problems. On the other hand, a RC can provide the reactive power support, which is capable of voltage regulation. Based on this viewpoint, this paper proposes a new framework of voltage regulation, in which the reactive power compensation by RCs is actively utilized. The proposed voltage regulation method combines two different control functions with consideration for over‐compensation avoidance. This paper ascertains the validity of proposed voltage regulation method through numerical simulations.     

汽车覆盖件弹塑性失稳机理实验模拟研究

利用YBT模型,结合密栅云纹试验,模拟了汽车用钢板的拉伸过程。通过记录、测量、计算和分析,获得试样全部变形过程中的整场连续、瞬时位移、应变和应力信息。结果表明,汽车覆盖件回弹类缺陷是卸载不均匀压缩诱发的局部弹性失稳;起皱类缺陷是加载不均匀导致的塑性失稳。     

LIPASE ACTIVITY AND STABILITY IN SUPERCRITICAL CARBON DIOXIDE

The use of a supercritical fluid as a medium for enzymatic reaction was investigated with respect to its application and reaction mechanism. Lipase could catalyze the reaction of hydrolysis and interes-terification in supercritical carbon dioxide at 35°C and 137 bar. There was no difference in the time course of interesterification between the untreated lipase and the lipase exposed to supercritical carbon dioxide indicating that the enzyme was not severely damaged.