三水铝石的粉碎机械力化学效就与热特性

使用振动球磨机将三水铝石粉体进行干式微粉碎.粉碎实验条件为介质球/试样(质量比)=8.5.研究调查了不同粉碎时间处理粉碎试样的机械力化学效应(平均粒径、结晶无定形和加热特性).结果表明,长时间粉碎,达到粉碎平衡,平均粒径趋于极限值.粉碎过程中未脱水.由于粉碎,加热脱水温度、结晶相变温度降低.     

Intestinal absorption and biological effects of orally administered amorphous silica particles

Although amorphous silica nanoparticles are widely used in the production of food products (e.g., as anticaking agents), there is little information available about their absorption and biological effects after oral exposure. Here, we examined the in vitro intestinal absorption and in vivo biological effects in mice of orally administered amorphous silica particles with diameters of 70, 300, and 1,000 nm (nSP70, mSP300, and mSP1000, respectively) and of nSP70 that had been surface-modified with carboxyl or amine groups (nSP70-C and nSP70-N, respectively). Analysis of intestinal absorption by means of the everted gut sac method combined with an inductively coupled plasma optical emission spectrometer showed that the intestinal absorption of nSP70-C was significantly greater than that of nSP70. The absorption of nSP70-N tended to be greater than that of nSP70; however, the results were not statistically significant. Our results indicate that silica nanoparticles can be absorbed through the intestine and that particle diameter and surface properties are major determinants of the degree of absorption. We also examined the biological effects of the silica particles after 28-day oral exposure in mice. Hematological, histopathological, and biochemical analyses showed no significant differences between control mice and mice treated with the silica particles, suggesting that the silica nanoparticles evaluated in this study are safe for use in food production.     

Solvent Extraction of Indium,Gallium, and Zinc Ions with Acidic Organophosphates having Bulky Alkyl Groups

The extraction equilibria of In³⁺, Ga³, and Zn²⁺ with bis(4‐ethylcyclohexyl)phosphoric acid (D4ECHPA), bis(4‐cyclohexylcyclohexyl)phosphoric acid (D4DCHPA), and bis(2‐ethylhexyl)phosphoric acid (D2EHPA) were investigated in acidic aqueous sulfate media. The order of extractability of metal ions is D4DCHPA > D2EHPA > D4ECHPA, which corresponds to the lipophilicity (log P) of the extractants. The separation factors, β_(In/Ga) and β_(Ga/Zn), of D4ECHPA and D4DCHPA are greater or comparable than that of D2EHPA, because of the steric hindrance of the bulky cyclohexyl groups. In³⁺ can be therefore separated from simulated liquor containing a high concentration of Zn²⁺ by D4DCHPA.     

The effect of chemical reaction on the mixing flow between aqueous solutions of acetic acid and ammonia

The basic characteristics of the reacting mixing flow of two streams were investigated. The reaction between aqueous solutions of ammonia and acetic acid, which produces ammonium acetate, was investigated in terms of the effect on the fluid–fluid interface of the mixing flow relative to fluids that did not react. The reaction between these solutions was negligibly exothermic, and there were minimal differences in density. The velocity field in the reacting mixing flow was quantitatively measured using high-speed time-resolved particle image velocimetry (PIV) and the behavior of the mixing flow was qualitatively investigated using laser-induced fluorescence (LIF). The jet width, the velocity field, the kinetic energy and the turbulent intensities are qualitatively estimated and discussed. It was found that the chemical reaction resulted in the suppression of the mixing flow.     

Reduction of in vitro allergenicity of buckwheat Fag e 1 through the Maillard-type glycosylation with polysaccharides

A major allergenic protein of buckwheat, Fag e 1 prepared from common buckwheat (Fagopyrum esculentum), was covalently linked with food-grade polysaccharides, arabinogalactan or xyloglucan through the controlled dry-heating at 60 °C under 65% relative humidity. The introduction of polysaccharide chain onto the molecular surface of Fag e 1 reduced the allergenicity of Fag e 1. The results revealed that the Maillard-type glycosylation of Fag e 1 with polysaccharides brought about a drastic reduction of the reactivity against human sera of buckwheat-allergy subjects, using immuno dot-blotting, QCM analysis and ELISA. In addition, the glycosylation of Fag e 1 yielded a great improvement of its surface functionality. Solubility of Fag e 1 at the neutral pH was substantially increased up to 13.5 times and 9.6 times by the conjugation with arabinogalactan and xyloglucan, respectively. Emulsifying properties of Fag e 1 were also improved by the glycosylation, of which both emulsifying activity and emulsion stability were more than 6 times higher than those of the native protein.     

Electricity markets volatility: estimates,regularities and risk management applications

The recent deregulation of the market for electric power in many parts of the US and Canada has expanded the set of potential tools for managing the types of risks faced by both generators and consumers of electric power. In particular manufacturing and other firms whose operations are powered by electricity now face, on a continuing basis, the engineering management decisions concerning whether they should buy or produce electricity, and if they are to buy or sell electricity, what types of contracts are optimum. These types of risk management decisions typically involve futures, forwards, options and other financial derivatives. The price and volatility of electric power are known to play an essential role in determining which of these instruments should be used. However, electricity as a commodity possesses certain special features not shared by other commodities and hence its risk properties are not yet well understood. In this paper we consider and test certain hypotheses about the properties of electricity price using recent market data. We find that electricity prices possess certain volatility and other systematic properties that can be characterized by the type and method of delivery of electricity. These properties can be used by firms in formulating their optimal demand and supply schedules of electric power.     

An approximate reasoning approach for optimal dynamic dispatch ofthermal generating units including auxiliary control

Fuzzy set theory is applied to decision-making in the optimal generation dispatch of thermal generating units. Operational requirements such as unit auxiliary start-up and shutdown create discrete zones of generation output. Plant operators are required to switch units dynamically from one output zone to another in order to keep track of the changing load. The problem arises when making the decision to switch zones for dynamic load dispatch, because of complicated operational conditions. The authors apply approximate reasoning in order to coordinate multiple system requirements and to make effective zone-switching decisions. Membership functions are introduced to measure generation-load balance, fuel cost, and time to stay in a zone. Approximate reasoning using these indices yields information concerning compatibility of output zones. Model analysis is used to demonstrate the flexibility and improved man-machine interface of the approach     

Inhibition of hepatic lipogenesis by 2-tetradecylglycidic acid

2-Tetradecylglycidic acid (TDGA), a hypoglycemic agent, has been found to be a very effective inhibitor of de novo fatty acid synthesis by isolated hepatocytes. A comparison was made between the effectiveness of TDGA and 5-(tetradecyloxy)-2-furoic acid (TOFA), a hypolipidemic agent, on the metabolic processes of isolated hepatocytes. These compounds are structurally related and both inhibit fatty acid synthesis; however, they have opposite effects from each other on the oxidation and esterification of fatty acids. TDGA inhibits whereas TOFA stimulates fatty acid oxidation. TDGA stimulates whereas TOFA inhibits fatty acid esterification.