Hydration of Beta Dicalcium Silicate Alone and in the Presence of CaCl2 or C2H5OH

Beta C₂S was hydrated at room temperature with and without added CaCl₂ or C₂H₅OH by methods previously studied for the hydration of C₃S, i.e. paste, bottle, and ball-mill hydration. The amount of reacted β-C₂S, the Ca(OH)₂ concentration in the liquid phase, the CaO/SiO₂ molar ratio, and the specific surface area of the hydrate were investigated. A topochemical reaction occurs between water and β-C₂S, resulting in the appearance of solid Ca(OH)₂ and a hydrated silicate with a CaO/SiO₂ molar ratio of ≃1. As the liquid phase becomes richer in Ca(OH)₂, the first hydrate transforms to one with a higher CaO/SiO₂ ratio. Addition of CaCl₂ increases the reaction rate and the surface area of the hydrate but to a much lesser extent than in the hydration of C₃S, whereas C₂H₆OH strongly depresses the hydration rate of β-C₂S, as observed for C₃S hydration.     

THINGS†

A concept of concrete object, or thing, is built that turns out to subsume the special concepts of thing found in the sciences. The construction proceeds in three stages. In the first, the concept of a substantial individual is introduced as anything that can combine with other individuals. The set of individuals is assigned the semi-group structure, and a number of notions, in particular those of part and of aggregate, are defined. In the second phase the notion of a substantial property, as different from that of attribute, is characterized. It is construed as a function on the set of substantial individuals. The assumption is made that properties are all definite and that they can conjoin but not disjoin; nor are negative properties countenanced. Further, the notions of.property precedence and of property neighbourhood are defined. It is postulated that substantial properties come in clusters. Laws are counted as special properties, namely as functional relations among substantial properties. In the third stage the notion of state is introduced and a thing is defined as a substantial individual equipped with all its possible states. Natural kinds or species are then defined with the help of the concept of a law, namely as the sets of things satisfying certain laws. The real world is assumed to be unique and to be constituted by things alone. Finally the notion of a concrete system is defined as a set of things together with the set of connections among them. The paper employs elementary logical, algebraic and set theoretical notions, and is hoped to belong in exact philosophy.     

Optical and thermal characteristics of glasses based on TeO 2

Glass samples have been synthesized in quaternary system based on TeO ₂–oxide within composition, 85TeO ₂–5Nb ₂O ₅–5ZnO–5Ag ₂O, 68TeO ₂–5Nb ₂O ₅–20ZnO–7Na ₂O and [(75?x)TeO ₂–5Nb ₂O ₅–20ZnO–xPbO, x = 7, 18 mol%]. Structural characterization of the glasses was studied with respect to their thermal stability, refractive indices, third order nonlinear optical susceptibility, IR spectra and Vickers hardness. For four different prepared glasses, density in the range from 5·3744 to 6·0731 g· cm ^???1, the glass transition temperature (T _g) in the range from 326 to 350 °C and refractive indices, n, in the range from 2·1273 to 2·2123 at 435 nm and Vickers hardness, H _v, in the range from 2·91 to 3·44 GPa were determined. The value of third order nonlinear optical susceptibilities ${\vert} {\chi}^{\text{(3)}}{\vert} {\approx} $ 17·9 ·10^{??? 13} esu of glass within composition, 68TeO ₂–5Nb ₂O ₅–20ZnO–7PbO, was measured by using degenerate four-wave mixing (DFWM).     

屈曲约束支撑力学性能试验加载制度研究

目前,由国内的加载制度检测得到的屈曲约束支撑性能相对较小,这导致大部分满足其他国家性能要求的构件无法应用于我国工程实践中。为了推动国产屈曲约束支撑的国际工程应用,以中国规范和日本规范规定的屈曲约束支撑力学性能检验方法为基础,分析规范中对最大变形幅值、变形范围和循环次数的要求;通过OpenSees建模分析,对不同加载历程下屈曲约束支撑的拟静力反复加载试验进行模拟,采用累积非弹性变形和累积滞回耗能来评估屈曲约束支撑的性能,将滞回能量的累积分布作为评估加载制度的幅值增长规律的参数;基于中日规范中屈曲约束支撑循环试验加载制度的定义以及在两种不同加载方式下屈曲约束支撑循环试验数值模拟的结果,提出用于屈曲约束支撑性能检验试验的新加载制度(GLP)。研究结果表明,GLP具有较大的累积非弹性变形,与所参照的累积滞回耗能分布吻合较好;其最大变形幅值为30%,与日本规范要求的最大钢芯应变水平相一致。     

Some Characteristics of Whole Corn: Whole Soybean (70:30) and Rice: Whole Soybean (70:30) Mixtures Processed by Simple Extrusion Cooking

Mixtures of corn or rice with dehulled soybeans (70:30) were extruded at three cone openings. Processing temperatures were inversely correlated with cone opening. As cone opening increased fat retention and nitrogen solubility index increased, while dispersibility, protein nutritive value and acceptability (as “atole”) by school children decreased. The PER and NPR of the mixtures were significantly (P < 0.05) correlated with processing temperature (r = 0.90 for both) and sensory score (r = 0.83 and 0.82, respectively). No correlation was observed between protein nutritive value and residual antiphysiological factors of the products. After storage of mixtures for 12 wk at 4° and 25° C, fat acidity values were lower than 2%; those stored at 35°C showed nearly 10%. All samples were equally acceptable.     

Hydration of Tricalcium Silicate

The kinetics of paste, bottle, and ball-mill hydration of 3CaO SiO₂ and the effects of additions of electrolytes and alcohols were studied. Paste and bottle hydrations proceed through periods of induction, acceleration, and decay. If 3CaO SiO₂ is hydrated in an excess of H₂O, as in bottle hydration, the reaction rate is lower than that for paste hydration. The ball-mill hydration rate is much the highest and is controlled by the removal of the hydrate layer coating the 3CaO SiO₂ particles. Electrolytes always accelerate and alcohols retard the reaction rate. Experimental results are discussed with reference to modern theories of the 3CaO SiO₂ hydration mechanism.     

ANALYSIS OF THE PUNGENT PRINCIPLES OF Capsicum annuum BY COMBINED GAS CHROMATOGRAPHY-MASS SPECTROMETRY

SUMMARY— The pungent principles of Capsicum annuum includes at least five closely related compounds . Four of these pungent compounds-capsaicin, dihydrocapsaicin, nordihydrocapsaicin and homodihydrocapsaicin-were separated by gas chromatography with a 3% SE-30 column and identified by combined gas chromatography-mass spectrometry. Separation of these compounds into oleoresin capsicum by gas chromatography is also reported.     

A Seminar for Real‐time Interactive Simulation of Engineering Projects: An Innovative Use of Video‐conferencing and IT‐based Educational Tools

Graduate‐level programs in project management continue to attract many engineers looking for tools and methods to help them deal with the complexity of their activities. In order to meet this demand, many universities are experimenting with new teaching methods, based on information and communications technologies. This article presents a teaching approach which consists in recreating the organizational context in which engineers generally have to manage their projects. In practical terms, it is a full‐day seminar that involves simulating a project from its launch until product delivery. Like most real projects, the activity takes place at more than one location simultaneously and relies on the intensive use of communications technologies, including video‐conferencing, to coordinate the work teams. Although the primary client base is graduate students, this method is just as relevant for professional engineers and undergraduate students. Over 400 participants have taken part in this seminar to date.