Effect of Organic Additives on Electrochemical Surface Precipitation and Polymorphism of CaCO3

The inhibition effect of three organic additives on the precipitation and polymorphism of CaCO₃ deposited on gold surfaces was investigated using electrochemical and microscopic techniques. Additives, two polyacrylic acid (PAA) polymers with different molecular weights (Mw 2100, Mw 30,000), and 1,2,4,5‐benzenetetracarboxylic acid (BTCA), were either added to the solution before or during deposition. In the presence of 100 ppm of one of the three additives in solution, almost no scale was observed on the surface for at least 24 hours. In the presence of lower concentrations of PAA Mw 2100, only distorted calcite crystals were obtained while with PAA Mw 30,000 the polymorph was spherical vaterite. A mixture of calcite and vaterite was observed with the BTCA additive. Addition of the polymers inhibits further nucleation and growth even if added after partial deposition of CaCO₃ while BTCA has no effect once nucleation has started. The results indicate that the inhibit ion effect of the PAA polymers is due to adsorption on the electrode surface while the effect of BTCA is related to chelation of calcium ions in solution.     

尖晶石型软磁铁氧体纳米材料的制备研究进展

介绍了软磁铁氧体纳米材料的特性,综述了近年来具有尖晶石结构的软磁铁氧体纳米材料的制备方法。其中包括:化学共沉淀法,水热法,溶胶-凝胶法,喷雾热解法,微乳液法,相转化法,超临界法,冲击波合成法,微波场下湿法合成,爆炸法,高能球磨法,自蔓延高温合成法等。详细介绍了各种制备方法的特点,研究进展及其发展趋势。     

The Challenge of the Market

Identifying markets for new or improved products for minor crops threatened with extinction is one critical component of any strategy intended to enhance prospects for sustainable production and use. Typically, however, activities linked to the sustainability of these commodities avoid addressing questions associated with assessing their commercial potential. After a brief review of this avoidance syndrome, this article presents a sample of practical, low-cost procedures to help evaluate the market prospects and procedures for crops like quinoa, while citing references to other methodological materials covering similar topics.     

Bayesian and Dempster-Shafer fusion

The Kalman Filter is traditionally viewed as a prediction-correction filtering algorithm. In this work we show that it can be viewed as a Bayesian fusion algorithm and derive it using Bayesian arguments. We begin with an outline of Bayes theory, using it to discuss well-known quantities such as priors, likelihood and posteriors, and we provide the basic Bayesian fusion equation. We derive the Kalman Filter from this equation using a novel method to evaluate the Chapman-Kolmogorov prediction integral. We then use the theory to fuse data from multiple sensors. Vying with this approach is the Dempster-Shafer theory, which deals with measures of “belief”, and is based on the nonclassical idea of “mass” as opposed to probability. Although these two measures look very similar, there are some differences. We point them out through outlining the ideas of the Dempster-Shafer theory and presenting the basic Dempster-Shafer fusion equation. Finally we compare the two methods, and discuss the relative merits and demerits using an illustrative example.     

A semiparametric model for compositional data analysis in presence of covariates on the simplex

Compositional data occur as natural realizations of multivariate observations comprising element proportions of some whole quantity. Such observations predominate in disciplines like geology, biology, ecology, economics and chemistry. Due to unit sum constraint on compositional data, specialized statistical methods are required for analyzing these data. Dirichlet distributions were originally used to study compositional data even though this family of distribution is not appropriate (see Aitchison, 1986) because of their extreme independence properties. Aitchison (1982) endeavored to provide a viable alternative to existing methods by employing Logistic Normal distribution to analyze such constrained data. However this family does not include the Dirichlet class and is therefore unable to address the issue of extreme independence. In this paper generalized Liouville family is investigated to model compositional data which includes covariates. This class permits distributions that admit negative or mixed correlation and also contains non-Dirichlet distributions with non-positive correlation and overcomes deficits in the Dirichlet class. Semiparametric Bayesian methods are proposed to estimate the probability density. Predictive distributions are used to assess performance of the model. The methods are illustrated on a real data set.     

活性炭的制备及应用新进展

综述了活性炭材料研究开发的新进展。重点介绍了煤、石油焦、沥青基活性炭的制备方法及针对不同用途的活性炭改性技术，为选择合适的活化方法和制备特殊功能的改性活性炭提供了参考。     

A Bayesian model for measurements on a set of instruments

A Bayesian model is proposed based on randomizing the systematic errors of the instruments. Conditions are identified under which the randomization reduces the expected bias in estimating a measured quantity. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 22–25, March, 2007.     

Interface Management within Construction: In Particular, Building Facade

This paper discusses the need for interface management within construction, with particular reference to building facade interfaces. It categorizes the three different types of interface management—physical, contractual, and organizational. The implication of interface management in construction contracting is discussed; it is explained how the U.K. procurement trends have changed, affecting the interface management within projects. U.K. cladding procurement is very fragmented, and the paper maps the development of a typical cladding system showing the complexities of interface management. Finally, the paper discusses CladdISS, a U.K. government funded research project to develop a standardized strategy for the design and management of window and cladding interfaces. It explains the principles of CladdISS with reference to process maps, action plans, management strategy, bibliography, advice on standards, materials, maintenance, joints, movement, and tolerances. This will enable strategies to be developed to avoid the endemic interface problems occurring on-site. It will also guide the management of the interfaces throughout the project.     

Real-world extensions to scheduling algorithms based on lagrangian relaxation

Recently, efficient scheduling algorithms based on Lagrangian relaxation have been proposed for scheduling parallel machine systems and job shops. In this article, we develop real-world extensions to these scheduling methods. In the first part of the paper, we consider the problem of scheduling single operation jobs on parallel identical machines and extend the methodology to handle multiple classes of jobs, taking into account setup times and setup costs. The proposed methodology uses Lagrangian relaxation and simulated annealing in a hybrid framework. In the second part of the paper, we consider a Lagrangian relaxation based method for scheduling job shops and extend it to obtain a scheduling methodology for a real-world flexible manufacturing system with centralized material handling. This research was supported in part by the Office of Naval Research and the Department of Science and Technology grant N00014-93-1017.