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.     

An application of Markov potential theory to Markovian decision processes

The aim of this paper is to identify the denumerable stochastic systems which have an optimal strategy, namely, to give general sufficient conditions of the existence of an optimal strategy for denumerable Markovian decision processes. The aim is accomplished by using Markov potential theory and showing the range of the validity of a method to find an optimal strategy called Howard's technique. Since Markov potential theory helps to characterize the properties of evaluations of strategies on such processes, it plays an important role to find the sufficient conditions mentioned above

For Markov potential theory, new concepts are introduced such as absorbable chains, quasi-potentials, etc., and using them, sufficient conditions for the existence of a solution of the equation x = f+Px are generalized to the one's for cyclic chains and multi-chains

The results obtained in this paper are as follows : if a system represents a strong Markov chain for any strategy, then there exists an optimal strategy with respect to the total or the mean expected earnings, and for any stochastic system there exists an optimal strategy with respect to the discounted total expected earnings.     

Preparation and Thermal Properties of Dense Polycrystalline Oxyhydroxyapatite

Solution-grown crystals of hydroxyapatite were sintered into polycrystalline oxyhydroxyapatite bodies, using the range 1050 to 1450°C. The heat capacity, thermal diffusivity, and thermal conductivity of the sintered bodies were measured by the laser flash method at 130–1000 K. The sintered bodies were 94.4 to 99.4% of theoretical density and 0.8 to 12 μm in grain size. Sintering is accompanied by grain growth and by vacancy formation and cell contraction due to thermal dehydration. Typical values of the heat capacity, thermal diffusivity, and thermal conductivity at room temperature are 0.73 J/g K, 0.0057 cm²/s and 0.013 J/s cm K, respectively. Low-temperature thermal conductivity increased with increasing temperature, similarly to that of amorphous solids. This odd behavior is discussed in terms of phonon mean free path.     

LIPID CLASSES, FATTY ACID COMPOSITIONS AND TRIACYLGLYCEROL MOLECULAR SPECIES FROM ADZUKI BEANS (VIGNA ANGULARIS)

The lipids extracted from adzuki beans grown in Japan were classified by thin-layer chromatography (TLC) into eight fractions. Molecular species and fatty acid distributions of triacylglycerols (TAGs) isolated from the total lipids in the beans were determined from a combination of argentation-TLC and gas chromatography. The major lipid components were phospholipids (PL; 63.5%) and TAG (21.2%), while hydrocarbons (5.1%), steryl esters (7.5%), free fatty acids (0.9%), diacylglycerols (1.3%) and monoacylglycerols (0.5%) were also present in minor proportions. Both major samples had high amounts of total unsaturated fatty acids, representing 62.1% for TAG and 65.9% for PL. Seventeen different molecular species were detected. The major TAG components were SMD (5.0%), S₂T (19.3%), SD₂ (13.8%), SMT (9.3%), MD₂ (4.5%), SDT (7.0%), D₃ (8.8%) and ST₂ (15.9%), where S, M, D and T denote a saturated fatty acid, a monoene, a diene and a triene, respectively.

PRACTICAL APPLICATIONS

This article describes the characteristics of lipid components, fatty acid compositions as well as the profiles of triacylglycerol (TAG) molecular species of adzuki beans. α-Linolenic (18:3 n -3) acid was detected as 24.8, 21.2 and 15.2% in the TAG, total lipids and phospholipids, respectively. The oil from legumes, except the profitable fatty acid content, could be a potential source of tocopherols. The data obtained in this study would be useful to both consumers and producers for manufacturing traditional adzuki confectionaries ( wagashi ) in Japan and elsewhere.     

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.     

真空压铸中型腔真空压力的理论计算及试验研究

针对真空压铸中型腔真空压力的下降规律进行了理论计算和试验研究。针对具体的真空系统进行了型腔排气理论曲线和实测曲线的对比,验证了这种计算方法的可行性,指出了真空压铸为了达到理想的型腔真空压力对于低速工艺选择的限制要求,并提出了一种通过计算理论排气时间来对真空系统设计和低速工艺制定进行优化的方法。     

Microstructures of SrTiO3 Internal Boundary Layer Capacitors During and After Processing and Resultant Electrical Properties

The microstructure of strontium titanate internal boundary layer capacitors at various stages in their processing was studied by transmission electron microscopy of rapidly quenched and normally cooled samples. Compositions containing excess TiO₂, Al₂O₃, and SiO₂ have a completely wetting liquid phase at the sintering temperature; during cooling Ti_nO_{2 n −1}, Magneli phases precipitate at multiple grain junctions. Diffused metal oxides and flux (Bi₂O₃, PbO, CuO, and B₂O₃) rapidly penetrate as a liquid phase along boundaries in postsintering heat treatment. This liquid phase disappears during slow cooling.     

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.     

Learning automaton as a model to simulate and analyse learning behaviour in rats

A technique is presented for using a learning automaton as a model to simulate and analyse learning behaviour in rats, and the usefulness of this model is illustrated. This automaton was proposed as a learning machine by Tsetlin (1961) and refined by Aso and Kimura (1976). Some learning properties of such an automaton are first examined and it is shown that the automaton can be used to simulate a variety of learning behaviour, composed of several kinds of action, by the proper selection of parameters. Secondly, a mathematical model of the learning experiment carried out in our laboratory with rats is formulated as an interactive system between a learning automaton and its environment. Finally, the effectiveness of the mathematical model is discussed and proved through the simulation and analysis of learning behaviour with multiple actions in a specific rat.     

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.