Purification and Characterization of an Endoprotease from Melon Fruit

An endoprotease was purified from melon fruit (Cucumis melo L.) by ammonium sulfate precipitation, gel filtration and ion-exchange chromatography using t-butyloxycarbonyl-Ala-Ala-Pro-Leu p-nitroanilide as a substrate. The molecular weight was estimated as 26,000 and isoelectric point pH 9.5. It preferentially hydrolyzed peptide bonds of the carboxyl terminal sides of Leu, Ala, His, Gin, and Am. Activity was strongly inhibited by diisopropyl phosphofluoridate, indicating the serine protease nature of the enzyme. The migration distance on electrophoresis, molecular weight and substrate specificity differed from cucumisin, a known protease from melon. This unusual protease may have potential for special food treatment applications.     

Optimized Energy‐Saving Speed Profile in Linear‐Motor Railway System

The most striking characteristic of linear‐motor railway system is that the structure consists of a primary and secondary linear induction motor (LIM). The primary side of the LIM is installed in a rolling stock, and the secondary side of LIM is installed on the track. The magnetic attractive vertical force produced by the LIM increases the running resistance since this force is in the same direction as the gravitational force due to which rolling stocks gain weight virtually from the track side of view. In addition, the efficiency of the LIM has different characteristics of efficiency compared with the rotary motor. Previous studies have focused on the design method of LIM to improve motor efficiency and decrease energy consumption. However, it is a well‐known fact that this kind of approach requires hardware renewal which requests large amount of investments. The purpose of this study is to analyze these characteristics of LIM effects and design the optimal speed profile to minimize the energy consumption as a linear‐motor railway system. This smart and economic energy‐saving approach is based on the optimization of speed profiles of the linear‐motor railway system using dynamic programming.     

Fast Electromagnetic Transient Simulations of Power Systems Utilizing Single‐Phase Phasor‐Based Modeling of Remote Systems

Electromagnetic transient (EMT) simulations of relatively large power systems have become quite common, for instance, in the case where simulations of HVDC converters are carried out with large ac power systems connected to the converters. Thus, the increase in computation time is a serious concern. To reduce computation time, this paper proposes a method to reduce computational demand of a remote power system which is located far from the source of a transient event to be simulated. In the proposed method, the remote power system, which is supposed to be represented by a three‐phase EMT‐based model, is reduced to a single‐phase phasor‐based model, and the size of the circuit to be simulated is thus reduced and the dynamics calculations of inductors and capacitors included in the remote power system are neglected. The calculation algorithm of generator models included in the remote power system is also simplified. The proposed method has been applied to EMT simulations of the WEST 10 benchmark power system prepared by the IEEJ, and it has been shown that the computation time is remarkably reduced without significant loss of accuracy if the portion assumed to be the remote power system is sufficiently far from the source of a transient event.     

Stress concentration formula useful for any dimensions of shoulder fillet in a round bar under tension and bending

In this work stress concentration factors (SCFs), K_t for a round bar with a fillet are considered on the basis of exact solutions, now available for special cases, and accurate numerical results. Then, a convenient K_t formula useful for any dimensions of the fillet is proposed. The conclusions can be summarised as follows: (i) For the limiting cases of deep (d) and shallow (s) fillet, the body force method is used to calculate the K_t values. Then, the formula are obtained as K_td and K_ts. (ii) On the one hand, upon comparison of K_t and K_td, it is found that K_t is nearly equal to K_td if the fillet is deep or blunt. (iii) On the other hand, if the fillet is sharp or shallow, K_t is mainly controlled by K_ts and the fillet depth. (iv) The fillet shape is classified into several groups according to the fillet radius and fillet depth. Then the least squares method is applied for calculation of K_t/K_td and K_t/K_ts. (v) Finally, a convenient formula is proposed that is useful for any dimensions of fillet in a round bar. The formula give SCFs with less than 1% error in most cases for any dimensions of fillet under tension and bending.     

Synthetic Mica Research in Japan

Research on the synthesis of mica was started in Japan in 1938. As the first step, compositions which crystallize easily were investigated. The next step was the determination of the temperature of crystallization from melts and the rate of crystal growth. Experiments with growing of crystals were performed and these fundamental properties were determined. Various types of mica were synthesized. The results of (1) the determination of temperature of crystallization and rate of growth of fluor-phlogopite from melts and (2) studies on the isomorphism in the various types of synthetic mica, e.g., chemical composition, crystal size, refractive index, electrical properties, heat of crystallization, and temperature of crystallization, are summarized. The practical uses of both synthetic mica and glass-bonded synthetic mica ceramics are described.     

利用中国甘蔗渣原料生产活性炭

以中国甘蔗渣为原料生产活性炭的研究,生产出具有比表面积1096×103m2/kg的活性炭.处理甘蔗渣的生产工艺是活化温度800℃,升温速度5℃/min.保持时间1.0h、水通入流量为6kg/kg-甘蔗渣.同时进行增加活性炭强度的实验,强度约为商品椰子壳活性炭强度的1/3.     

界面涂层与基体对先进CVI-SiC/SiC复合材料性能的影响

对含有几种典型界面结构和SiC纳米线的CVI-SiC/SiC复合材料的弯曲性能和断裂韧性进行了比较研究. 研究表明: 界面涂层对SiC/SiC的力学性能至关重要, 120nm厚的碳界面涂层使材料的强度与韧性都增加一倍; 在用140nm厚的SiC层将该碳层分为更薄的两层, 形成C/SiC/C多层界面涂层时, 材料的强度没有明显的变化, 而断裂韧性则略有提高. 对基体中弥散分布有SiC纳米线的SiC/SiC的力学性能研究表明, SiC纳米线具有非常高的强化效率, 使SiC/SiC复合材料具有更高的强度和韧性.     

基于波动法的静水压力下环肋圆柱壳耦合振动特性研究

研究了静水压力下环肋圆柱壳的振动特性。在Flügge理论的基础上,考虑流体的影响,通过变换轴向波数,先后采用波动法和牛顿迭代法得到了不同边界条件下环肋圆柱壳的固有频率值。经过与已有文献数据进行对比,验证了研究的有效性和正确性。通过算例,分析了静水压力、肋条截面尺寸和数目、边界条件等因素对水下环肋圆柱壳固有频率的影响。     

Semi-continuous Hydrolysis of Sweet Potato Raw Starch by Chalara paradoxa Glucoamylase

Effect of preservatives was investigated on semi-continuous digestion of sweet potato raw starch by Chalara paradoxa glucoamylase which digests both raw and gelatinized starch. Potassium metabisulfite strongly inhibited raw starch digesting activity (RDA) although gelatinized starch digesting activity was only slightly inhibited. Potassium sorbate, among the preservatives examined, showed the weakest inhibition (below 10%) on RDA. In the presence of potassium sorbate, semi-continuous digestion of sweet potato raw starch in a 20L scale hollow fiber UF membrane pilot reactor proceeded efficiently at 30% (w/v) initial concentration of raw starch at pH 5.0 and 40°C. Glucose production was 5.7 to 6.0 g/hr/L.