Thermodynamic Assessment of the System MnO-NiO

The thermodynamic properties of pure MnO and NiO were analyzed in terms of the Debye model and a model for the magnetic transitions. The classical formula R In (β+ 1) for the magnetic entropy was found to overestimate the effect of magnetic ordering in these systems. A previous interpretation of the data for NiO was corrected. Thermodynamic functions were derived for the solid and liquid states and are given as analytic expressions. A previous assessment of the Gibbs energy of the solid solution (Mn, Ni)O from activity data was modified on statistical grounds. The results indicate that there should be a miscibility gap below 41O°C. By estimating the Gibbs energy of the liquid phase, it was possible to calculate the complete phase diagram.     

Solid-State Reactions between CaO Powder and Fe2O3

Diffusion couples are used to study the reaction between CaO powder and Fe₂O₃ All heat treatments were performed in air. The growth and morphology of calcium ferrites is studied at different temperatures. It is shown that CaO·2Fe₂O₃, starts to form at about 1125°C, while the accepted phase diagram for equilibrium with air predicts a temperature of 1155°C.     

Thermodynamic Assessment of the System CoO-MnO

The thermodynamic properties of pure CoO and CoO-MnO solutions have been analyzed in terms of thermodynamic models applying various experimental data. Expressions for the Gibbs energy of the individual phases have been obtained and the phase diagram is calculated. It reveals a homogeneous solid solution at temperatures above room temperature but a miscibility gap at very low temperatures.     

Comparison of selection procedures for the formation of homogeneous groups in clinical tests of dental care agents

Dental trials of new dental care formulations are studied with regard to specific quality characteristics such as inhibition of plaque formation and reduction of gingival bleeding, and require homogeneous panels of test persons in which both systematic and random sources of experimental error are excluded. The homogeneous panels must be formed from an available pool of test persons (global panel) so that each panel as a subset presents the same dental features on average and can be compared statistically one with another. This is a necessary condition for a valid scientific conclusion to be obtained from comparative dental studies. This type of homogeneous group division of a global panel can clearly be based on other medical features.
Four selection procedures for the formation of homogeneous panels from the global panel were compared quantitatively with regard to their efficiency and homogeneity of group division, namely:
— randomization method;
— block target method;
— median pair method;
— block median pair method.
With the exception of the randomization method, which can be applied more generally, the other selection methods require a preliminary study of the available test persons with regard to their medical features.
A comparison of the four selection procedures shows that the three other methods are more likely to provide more homogeneous panels than the randomization method.
Comparaison des procedures de selection concernant la formation de groupes homogènes dans les tests cliniques des agents de soins dentaires     

ALGAL GLYCEROL PRODUCTION: INITIAL GLYCEROL SYNTHESIS KINETICS

A review of previous work has allowed presentation of a unified conceptual model relating the important biochemical mechanisms involved in regulating glycerol production in halophilic algae. Experimental results on the initial rate of glycerol synthesis are reported which are used to indicate sodium transport may be the rate limiting step. These and other related results are discussed in relation to the model, and to algal glycerol process considerations.     

用小规模试验数据预测全尺寸火灾试验结果

在消防界，很多人都想用小规模试验数据来预测全尺寸火灾试验的最终结果。为了通过模拟平行板试验的中等规模试验来达到这个目的，并且把试验结果与FM认可的25ft墙脚火试验（ANSIFM4880）的结果进行比较。利用从实验室试验得来的数据开发了一个模型，用来预测燃烧平行板材所获得的全部热释放速率。对于不同的板材，平行板材下面的沙盘燃烧器释放的速率也随之不同。比较结果非常不错。但是，同25ft墙脚试验的比较显示，通过修正空间和燃烧器大小可以获得与平行板材构造更佳的相关性。     

DETERMINATION OF FIRMNESS AND SUGAR CONTENT OF APPLES USING NEAR‐INFRARED DIFFUSE REFLECTANCE1

The objective of this research was to study the potential of near‐infrared (NIR) diffuse reflectance between 800 nm and 1700 nm for determining the firmness and sugar content of apples and to ascertain the effects of apple peel and variety on the NIR prediction of these two quality attributes. The spectral reflectance data were acquired from both peeled and unpeeled ‘Empire', ‘Golden Delicious', and ‘Red Delicious’ apples. Statistical models were developed using principal component analysis/regression. Lower correlations of prediction were obtained (r=0.38 to 0.58) between NIR measurement and Magness‐Taylor firmness for both unpeeled and peeled fruit, with the standard errors of prediction (SEP) between 6.6 N and 10.1 N. Improved predictions were obtained when NIR reflectance was correlated with the slope of the Magness‐Taylor force‐deformation curves. Excellent predictions of the sugar content in peeled apples were obtained (r=0.93 to 0.97; SEP=0.37 to 0.42 °Brix). The SEP, on average, increased by about 0.17 °Brix for the unpeeled apples. Variety did not have a large effect on the model performance on sugar content predictions.     

SUSPENSION CHARACTERISTICS OF LARGE CYLINDERS IN AGITATED TANKS

Considerable research has been done concerning solid suspension in agitated tanks. Typically, such studies concern slurries or granular material, such as sand, and involve minimum suspension rotational speeds or suspension homogeneity.

The objectives of this work are similar, however we are concerned with rather large cylinders of varying length to diameter ratios. The work involves: 1) the determination of minimum impeller rotational speed for suspension similar to criterion used by Zwietering, 2) the measurement of suspension heights and times, 3) an investigation into whether the correlations by Zwietering, Kolar and Rieger et al., can be used for predicting minimum suspension rotational speed and 4) weight fraction effects on minimum suspension rotational speed.     

OPTIMAL STEP FUNCTION APPROXIMATIONS TO UTILITY LOAD DURATION CURVES

Utility load duration curves are often approximated by step functions, especially in the context of energy modeling and utility scheduling. This paper presents a method of constructing an optimal n-step approximation to a load duration curve.