Fractal Structure of Deformed Potato Starch and Its Sorption Characteristics

A deformation of microstructure was attempted on native potato starch and the change in the microstructure was analyzed from the fractal view point. The surface area calculated from the monolayer molecular number was different depending on the molecules used (Ar, N₂, Kr, 1-propanol, and benzene), which showed the surface microstructure was a fractal with the dimension 2.1-2.4. The specific surface area measured using N₂ and benzene was a function of the mean diameter of the material particles, which also showed that the porous structure of the particle was a fractal with the dimension 2.2-3.0. On the other hand, the sorption isotherm of water vapor was independent of particle diameter.     

Heuristics free group method of data handling algorithm of generating optimal partial polynomials with application to air pollution prediction†

In this paper a revised GMDH (Group Method of Data Handling) algorithm is developed in which heuristicsare not required such as dividing the available date. into training data and checking data, predetermining the structure of the partial polynomials, or predetermining the number of intermediate variables. In this algorithm the prediction error criterion, such as PSS (Prediction Sum of Squares) or AIC (Akaike's Information Criterion) evaluated from all the available data, in used as a criterion for generating optimal partial polynomials, for selecting intermediate variables and for stopping the multilayered iterative computation. This heuristics freeGMDH algorithm is applied to non-linear modelling for short-term prediction of air pollution concentration. By using the time series data of SO₂, concentration, the wind velocity and the wind direction in Tokushima; Japan, a suitable model for predicting SO₂concentration at a few hours in advance is developed. The predicted results obtained by the revised GMDH model are compared with the results obtained by a linear regression model, a linear autoregressive model and a. basic GMDH model.     

Electronic Conductivity, Seebeck Coefficient, and Defect Structure of La1-xSrxFeO3 (x=0.l, 0.25)

The electrical conductivity and Seebeck coefficients of La_1-xSr _x FeO₃ ( x =0.1, 0.25) were measured as a function of oxygen partial pressure, P_O2, at T =900° to 1300°C. The electrical conduction was p type in the higher P_O2 range, and n type in the lower P _O2 range. The Seebeck coefficient indicated that the conduction was due to electron hopping between Fe^×_Fe and Fe_Fe, in the higher P_O2 range and electron hopping between Fe'_Fe and Fe^×_Fe in the lower range. The carrier concentrations were calculated from the values of electrical conductivity and Seebeck coefficient. From the P _O2 dependences of the carrier concentrations, the defect structure of La_1-xSr _x FeO₃ was determined. It was found that the electrical properties can be described by considering the imperfections Sr_La, Vo , Fe_Fe, and Fe'_Fe.     

Synthesis and Thermal Stability of Aluminum Titanate Solid Solutions

Aluminum titanate solid solutions with empirical formulas of Al₂Ti_1-xZr_xO₅, Al_6(2-x)(6+x)Si_6x/(6+x)□_6x/(6+x)TiO₅, and Al_2(1-x)Mg_xTi_1+xO₅ were synthesized by reaction sintering and annealed at 900° to 1300°C in air to evaluate the thermal stability. Substitution of Al in Al₂TiO₅ by Si and 2Al by Mg and Ti ions to form solid solutions such as AI_{6(2-x)/(6+x)l-Si}6x/(6+x)□_6x/(6+x)TiO₅, and Al_2(1-x)Mg_xTi_1+xO₅ was effective in controlling the thermal decomposition, but substitution of Ti by Zr had little effect.     

Optimal maintenance policies with lead times and repair

Maintenance policies with lead times and repair are discussed. We first discuss ordering policy with repair and refer to inspection-ordering policy. In each policy, as a criterion of optimality, we apply cost effectiveness which balances system effectiveness and cost, and obtain the optimal policies. It is shown that, under certain conditions, there exists a finite and unique optimal policy.     

最优预见伺服系统与最优预见FF补偿系统的统一处理

最优预见伺服系统一般与基本最优伺服系统共用同一个二次型性能指标函数设计预见前馈补偿项,其设计的着眼点是进一步减小性能指标函数.当控制系统的基本反馈部分不是采用最优控制方法设计时,历史上采用另一个性能指标函数设计预见前馈补偿,并把所得系统称为预见FF(前馈)补偿系统.这里把两种设计方法统一起来处理后,不仅最优预见伺服系统与最优预见FF补偿系统都仅仅是特例,而且给设计者扩大了选择的余地.最后给出了数值仿真,把这种设计方法与最优伺服系统、最优预见伺服系统进行了比较.     

真空处理对薄壁球铁组织性能的影响

制备了壁厚呈阶梯状的薄壁球墨铸铁件,研究了不同真空保压时间对薄壁球墨铸铁组织及石墨形貌的影响.结果表明,球墨铸铁合金熔体经过合适时间的真空保压,能够有效提高组织中的石墨数量,消除组织中分布的较大尺寸石墨.对于壁厚为2 mm的铸件,真空保压3 min后,组织性能最优.阶梯状铸件中不同壁厚部位中的珠光体率对熔体中的熔存含氧量的敏感度不同.熔体经真空保压3 min后,壁厚为4 mm和6 mm部位的珠光体率下降16%,而薄壁2 mm的部位珠光体率基本不变.     

Effects of Polymers on Secondary Nucleation of Ice Crystals

The kinetics of ice crystallization in various polymer solutions were studied by the thermal response method in a batch crystallizer. Polymers suppress the secondary nucleation of ice crystals, depending on the kinds of polymer and concentration. The decrease of the nucleation rate constant in polymer solutions was related to the increase of viscosity. The effects of polymers on the nucleation rate were also observed in solutions containing low molecular weight compounds.     

FOOD TEXTURE AND TASTE: A REVIEW

The subjective measurement of food texture and the objective measurement based on a rheological model are described to clarify the relationship between texture and taste. The authors suggest that the most important sensory property is texture in foods which have relatively low flavor intensity. Additionally, from the fact that the multidimensional evaluation of palatability of foods is strongly influenced by properties requiring physical measurement, they propose the introduction of a new concept, physical taste, for making effective evaluations of food palatability. More quantitative texture studies related to food quality are required as well as research on the traditional four or five basic tastes.     

Pressure Rises Due to Arc under Insulating Oil in Closed Vessel—Pressure Fluctuation of Depth Direction in Oil

When a fault arc occurs in oil‐filled electric equipment, it generates a flammable gas and a dynamic pressure rise. In this study, the pressure rises due to the arc are measured in a closed vessel containing air and oil for different arc depths. The pressure rises in air and oil with different depth are measured under experimental conditions involving an arc current 6.6 kA, an arc duration of 100 ms. Experimental results show that the frequency of pressure fluctuation varies with the depth of the arc. Our approximate calculation of the pressure fluctuation with consideration of the oil flux is consistent with the experimental results.