Tetragonal to monoclinic transformation and microstructural evolution in ZrO2–9.7 mol% MgO during cyclic heating and cooling

The tetragonal (t) to monoclinic (m) transformation behaviour and its relationship to microstructural evolution were investigated by means of dilatometry and transmission electron microscopy for ZrO2–9.7 mol% MgO during cyclic heating and cooling between room temperature and 1490 K. In the as-sintered specimens, fine oblate ellipsoidal t-phase precipitates, 20–50 nm in diameter and 100–200 nm long, were distributed in the cubic (c)-phase matrix. They were below a critical size for transformation and exhibited no transformation in the first three cycles. In the fourth and further cycles, transformation occurred in two distinct stages. A low-temperature stage appeared at 850–1000 K on heating and at 400–700 K on cooling, while a high-temperature stage appeared at 1350–1400 K on heating and at 1000–1200 K on cooling. With the increasing number of cycles, at first the size of low-temperature stages increased and then decreased above ten cycles accompanying the development of the high-temperature stage. During cyclic heating and cooling, coarsening of ellipsoidal precipitates and decomposition of c- and t-phases occurred. As a result of the decomposition, MgO particles and a new m-phase containing a very low concentration of MgO were produced. The coarsened ellipsoidal t-phase precipitates were responsible for the low-temperature stage. The new m- or t-phase containing very low MgO produced by the decomposition was responsible for the high-temperature stage.     

Effects of Oxygen Absorber and Temperature on ω3 Polyunsaturated Fatty Acids of Sardine Oil during Storage

To prevent loss of w3 polyunsaturated fatty acids over long-term preservation, the effects of temperature and oxygen absorber on the fatty acids of sardine oil stored in air-tight film were studied. The fatty acids of sardine oil and lipids in the diet of experimental animals rapidly decreased over 1 month at 22°C. The amounts in the diet decreased slowly at 2°C; however, no alterations in the oil samples were observed for 6 months. Also, the amounts did not change at -30°C. Significant changes in samples treated with oxygen absorber were not observed under all temperatures during 6 months storage (P > 0.05). These results indicate that treatment with an oxygen absorber and/or freezing can prevent ω3 polyunsaturated fatty acids of fish oil from decreasing during storage.     

Design of a fixed-point smoother based on an innovations theory for white gaussian plus coloured observation noise

The optimal fixed-point smoother is designed based on an innovations theory for the white gaussian plus coloured observation noise in linear continuous systems. The signals to be estimated are non-stationary or stationary stochastic processes. The proposed fixed-point smoothing algorithm calculates estimates sequentially by using the observed value, the autocovariance function of the signal plus the coloured observation noise process and the cross-covariance function of the signal with the observed value.     

Acid Urease: Reduction of Ethyl Carbamate Formation in Sherry under Simulated Baking Conditions

Acid urease derived from Lactobacillus fermentum was applied to reduce ethyl cthe target level (90 μg/L). However, complete prearbamate (EC) formation in California sherry production. Commercial sherry and sherry base were treated with urease under different conditions. Amounts of urea were determined and EC amounts were monitored by gas chromatography. Urea removal by acid urease reduced EC formation during the baking process and effectively maintained EC concentrations below vention of EC was not achieved because of precursors other than urea.     

Fermentation of Soy Sauce with Immobilized Whole Cells

Soy sauce was produced continuously for 80 days in 280 liter column-type reactors containing immobilized whole cells of Pediococcus halophilus, Saccharomyces rouxii, and Torulopsis versatilis entrapped in calcium alginate gels. The divided lactic acid and alcohol fermentation by viable cells of three kinds with feed solution obtained from enzymatic hydrolyzate of koji and defatted soybean meal proceeded in shorter time than a complex fermentation of moromi (soy sauce mash) in the slurry state. The refined products fermented by this process had good taste and flavor, and were close to the conventional soy sauce with respect to organic acid and aroma components.     

SCREENING OF RESISTANT TRIACYLGLYCEROLS TO THE PANCREATIC LIPASE AND THEIR POTENTIALITIES AS A DIGESTIVE RETARDANT

A gradual retarding of lipid digestion and absorption might contribute to preventing the visceral fat accumulation and obesity in humans. The lipolysis rates of different triacylglycerols (TAGs) by pancreatic lipase in vitro were studied in order to find suitable components as a retardant for lipolysis. Several TAGs containing longer acyl chains than stearic acid or containing unsaturated fatty acids whose double bonds are located closely to the carboxyl group like petroserinic and γ-linolenic acid showed significantly lower lipolysis rates as compared with triolein (OOO) control. Most of these resistant TAGs contributed to decelerating the lipolysis rate when replaced at 10% into the OOO control. Especially, 1-behenoyl-2,3-dioleoyl- rac -glycerol (BOO) was comprehensively thought to be a suitable TAG as a digestive retardant among them. Each 10% replacement of edible oils by BOO gave 15% to 30% reduction of the lipolysis rate in vitro . Resistant TAGs that are able to melt or solubilize into liquid oil at body temperature have some potential as a digestive retardant for lipids.

PRACTICAL APPLICATIONS

Visceral fat accumulation and obesity in humans are thought to be correlated with the rate of lipid digestion and absorption. The entire rate of lipid absorption is controlled by their partial replacement with some digestive retardant. Resistant triacylglycerols may have some potential as a digestive retardant of lipids. Results of the present study propose a new fat system for foods with antiobesity effect.     

Structure of operators'' mental models in coping with anomalies occurring in nuclear power plants

Accidents occurring in nuclear power plants cannot be depended upon to train experts of nuclear operators. Generally, this expertise is developed through the simulator training. In this training course, only limited varieties of malfunctions can be presented. Thus, it would be impossible for operators to cope with any other possible anomalies of diverse varieties. Operators have to reorganize knowledge and experiences obtained in the training. Of course, prescribed procedures are far from covering them. This paper presents the structure and contents of a “operator's mental model” and it can deal with flexible operations under any situation. Based on the record of the simulator experiments, in-depth analyses were conducted by interviewing with experienced operators in order to model operators' thinking patterns and also to arrive at the aims behind their actions and utterances. Summarizing the findings obtained, fundamental functions of the mental model in coping with anomalies resulted in the following: (1) suggesting suitable preventive measures by envisioning the ongoing (future) scenario of plant dynamics; (2) identifying causes by investigating symptoms and implying causal remedies to eliminate them or to avoid influences from them and (3) adopting immediate responses simply formulated by “if alarm A then action B”. These functions, as well as the mental model itself, can be made available by getting information on plant status and operator's structured knowledge together. The substances and structures of the mental models could be proposed, including implications of how to create it for a specific event, and finally they were synthesized into a more generalized format.     

Stabilization of Power Supply for the Shinkansen with Power Converters

In the Tokaido Shinkansen, rolling stock types have been unified as an inverter controlled type, which was introduced after Series 300. As a result, the input power factor of the main converter used in the rolling stock has been controlled to 1. In accordance with this change, the role of reactive compensation of static var compensators (SVC) has shifted from the load power of trains to the power consumed by the reactance in the electrical power system. Therefore, when taking into consideration the aging of power converters, it is time to reassess their layout and the configuration for the future of the Tokaido Shinkansen. We reassessed the equipment configuration, capacity, and layout of power converters and verified the impact on the stabilization of the power supply when introducing self‐commutated power converters.     

ENZYMATIC CHARACTERISTICS OF TRYPSIN FROM PYLORIC CECA OF SPOTTED MACKEREL (SCOMBER AUSTRALASICUS)

Trypsin was purified from the pyloric ceca of spotted mackerel (Scomber australasicus) by gel filtration on Sephacryl S‐200 and Sephadex G‐50. The purification and yield were 20‐fold and 81%, respectively, as compared to those in the starting crude extract. Final enzyme preparation was nearly homogeneous in sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) and the molecular weight of the enzyme was estimated to be 24,000 Da by SDS–PAGE. The trypsin was stable at pH 5–11 for 30 min at 30C, and its maximal activity against N^α‐p‐tosyl‐L‐arginine methyl ester was pH 8.0. Trypsin was heat‐stable up to about 50C for 15 min at pH 8.0. Optimum temperature of the trypsin enzyme was 60C. The enzyme was stabilized by calcium ion. The purified trypsin was strongly inhibited by serine protease inhibitors such as N‐p‐tosyl‐L‐lysine chloromethyl ketone and soybean trypsin inhibitor, suggesting that it is a trypsin‐like serine protease. N‐Terminal amino acid sequence of spotted mackerel trypsin was IVGGYECTAHSQPHQVSLNS.     

Design of recursive fixed-point smoother using covariance information in linear discrete-time systems

A recursive fixed-point smoother and filter, for linear discrete-time systems, are designed using the observed value and the covariance information of signal and observation noise for white gaussian and white gaussian plus coloured observation noise.