Research on the Influence of the Type of Surfactant and Concentrator in Aqueous Dispersion of Pigments

This work reports tests performed to evaluate the stability of aqueous dispersions of inorganic oxide pigments with different specific surface areas, with the use of anionic and non-ionic surfactants and concentrators. Color mixtures of oxide compounds of blue, green, olive and brown with the unit cell spinel structure were used as pigments. The sodium salt of sulfosuccinic acid monoester, oxyethylenated nonylphenol and ethoxylated derivatives of lauryl alcohol, fatty alcohol and fatty amine were used as surfactants. The concentrators used were: poly(vinyl alcohol), the sodium salt of carboxymethyl cellulose as well as a water-based polyurethane oligomer. The highest dispersion efficiency was found for dispersed systems in which surfactant and concentrator were incorporated in the formula. The one containing the sodium salt of carboxymethyl cellulose or polyurethane oligomer with ethoxylated saturated fatty alcohol or fatty amine was found to be the most efficient. It was discovered that a higher dispersion efficiency corresponds to pigments with larger specific surface. The efficiency is also found to improve when the concentrator is an acrylic polymer or copolymer made up of two acrylic species. In this case, the concentrator interaction with the surfactant is more effective if the value of its boundary viscosity number is higher. This observation confirms the existence of interactions between macro-chains of the concentrator and surfactant molecules forming micelles with the pigment particles.     

Texture Assessment of Magnetically Processed Iron Titanate

Untextured and highly textured iron titanate specimens were produced by vacuum filtering iron titanate-ethanol suspensions in the absence and presence of a strong magnetic field, respectively. Crystallographic texture was assessed by measuring X-ray pole figures on surfaces parallel and perpendicular to the field direction for several peaks in each system. Morphological texture was assessed by measuring grain size as a function of angle to a reference direction. Results indicate that magnetic field processing imposes a strong, fiber-type texture on the order of 30 times random, with the b -axis parallel to the applied field. Additionally, morphological texturing is absent for the grain sizes studied in this work.     

Intrinsic flame resistance of polyurethane flexible foams: Unexpectedly low flammability without any flame retardant

Virgin polyurethane flexible foams are widely assumed to be highly flammable materials. The flammability of three model polyurethane flexible foams suggests that this may not be universally true. Two of them show unexpectedly low flammability in the limiting oxygen index test and pass flammability tests such as FMVSS 302 and FAR 25.853. Cone calorimetric measurements at 25 kW/m² and 50 kW/m² furthermore show a high resistance against ignition and demonstrate the self‐extinguishing properties of these two virgin, flame‐retardant‐free, polyurethane flexible foams.     

Effects of firm and IT characteristics on the value of e-commerce initiatives: An inductive theoretical framework

We explore the theoretical foundations on how firm and IT characteristics explain the market value variations in e-commerce initiatives by examining the announcements of 946 e-commerce initiatives in the public media. Our approach combines the Event study methodology and Decision tree induction to examine the main and interaction effects of IT and firm characteristics on Cumulative Abnormal Returns (CAR). In particular, we generate complex interaction models that can guide e-commerce investment decisions so managers can know, for example, which combination of IT and firm characteristics are more likely to be viewed positively by investors. The selected study variables as well as explanation of the proposed framework are informed by innovation, resource-based view, transaction cost economics and complementarity theories. We have inductively developed a set of propositions that can be deductively tested to assess the validity of our proposed theoretical framework. Hence our study provides an initial roadmap for theory development on e-commerce and CAR.     

面向内存文件系统的数据一致性更新机制研究

近年来,研究界提出了多种管理新型存储级内存的内存文件系统,例如BPFS,PMFS和SIMFS。由于内存文件系统的设备访问方式和I/O路径不同于传统面向块设备的文件系统,适用于内存文件系统的数据一致性更新机制尚未得到很好的研究。为此,提出一种适用于内存文件系统的直接拷贝的数据一致性更新机制,讨论多种数据一致性更新机制在内存文件系统中的优缺点,并以内存文件系统SIMFS为基础,实现多种支持不同数据一致性更新机制的SIMFS版本。通过测试基准测试了各个SIMFS版本的性能,并分析了不同数据一致性更新机制对内存文件系统的整体性能的影响。实验结果表明,提出的直接拷贝机制在内存文件系统中取得了最好的性能。     

Three-way analysis of dyadic social interactions.

Proposes a method for analyzing data from dyadic social interactions across 3 dichotomous variables. By accounting for the likely interdependency between 2 scores from a dyad, problems incurred with traditional analyses are circumvented. The analysis is demonstrated by an examination of data from 4 groups of 41 parent–child dyads: mother–daughter, mother–son, father–daughter, and father–son. The effects of sex-of-S, sex-of-partner, familial relationship between S and partner, and the interaction of these factors were tested. Results are compared to results derived from a repeated-measures ANOVA. It is shown that the latter analysis may mask important features of the data. (1 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mobile robot path planning based on hierarchical hexagonal decomposition and artificial potential fields

In this article, a new algorithm based on an artificial potential field and hierarchical cell decomposition technique is developed to solve the find-path problem for a mobile robot. The complete map of the workspace including obstacle locations is assumed to be known a priori. The basic cell structure used for decomposition is a hexagon. The artificial potential field is based on an attractive force from the goal position and repelling forces from the obstacles. Computer simulations of the algorithm for various obstacle scenarios are also presented. © 1994 John Wiley & Sons, Inc.     

A probabilistic framework for specular shape-from-shading

One of the problems that hinders conventional methods for shape-from-shading is the presence of local specularities which may be misidentified as high curvature surface features. In this paper we address the problem of estimating the proportions of Lambertian and specular reflection components in order to improve the quality of surface normal information recoverable using shape-from-shading. The framework for our study is provided by the iterated conditional modes algorithm. We develop a maximum a posteriori probability (MAP) estimation method for estimating the mixing proportions for Lambertian and specular reflectance, and also, for recovering local surface normals. The MAP estimation scheme has two model ingredients. First, there are separate conditional measurement densities which describe the distributions of surface normal directions for the Lambertian and specular reflectance components. We experimentally compare three different models for the specular component. The second ingredient is a smoothness prior which models the distribution of surface normal directions over local image regions. We demonstrate the utility of method on real-world data. Ground truth data is provided by imagery obtained with crossed polaroid filters. This reveals not only that the method accurately estimates the proportion of specular reflection, but that it also results in good surface normal reconstruction in the proximity of specular highlights.