Color and visual complexity in abstract images: Part II

There are a limited number of studies examining color, visual complexity, and visual interest together, and one of the recent studies that tried to bring a new understanding to the association between color, visual complexity, and visual interest was the first part of the current study. Most of the well‐known color studies researching the effects of color on psychology, physiology, emotion, mood, attention, well‐being, visual complexity, and visual interest used isolated color patches that might be lacking in reflecting the dominating factors. Thus, the aim of this study was to find the relationship between visual complexity, visual interest, and color difference (ΔE) values of colors in abstract images, and it was hypothesized that, as the average ΔE value of colors in an abstract image increases, visual interest and visual complexity will increase until reaching a threshold where visual interest and visual complexity start to decrease. In order to test the hypothesis, a new abstract image was generated and colored. The generated abstract image was rated by 120 undergraduate students from the Faculty of Art, Design and Architecture. As the results of the study indicated, there was an inverted U‐curve relationship between average ΔE values and both visual interest and visual complexity in abstract images.     

Development of a comprehensive visual dataset based on a CIE blue color center: Assessment of color difference formulae using various statistical methods

The objectives of this work were to develop a comprehensive visual dataset around one CIE blue color center, NCSU‐B1, and to use the new dataset to test the performance of the major color difference formulae in this region of color space based on various statistical methods. The dataset comprised of 66 dyed polyester fabrics with small color differences ($\Delta E_{{\rm ab}}^* < 5$ ) around a CIE blue color center. The visual difference between each sample and the color center was assessed by 26 observers in three separate sittings using a modified AATCC gray scale and a total of 5148 assessments were obtained. The performance of CIELAB, CIE94, CMC(l:c), BFD(l:c), and CIEDE2000 (K_L:K_C:K_H) color difference formulae based on the blue dataset was evaluated at various K_L (or l) values using PF/3, conventional correlation coefficient (r), Spearman rank correlation coefficient (ρ) and the STRESS function. The optimum range for K_L (or l) was found to be 1–1.3 based on PF/3, 1.4–1.7 based on r, and 1–1.4 based on STRESS, and in these ranges the performances of CIEDE2000, CMC, BFD and CIE94 were not statistically different at the 95% confidence level. At K_L (or l) = 1, the performance of CIEDE2000 was statistically improved compared to CMC, CIE94 and CIELAB. Also, for NCSU‐B1, the difference in the performance of CMC (2:1) from the performance of CMC (1:1) was statistically insignificant at 95% confidence. The same result was obtained when the performance of all the weighted color difference formulae were compared for K_L (or l) 1 versus 2. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2011     

Segmentation of map image using opponent color dimensions

This article describes a method for segmentation of color geographic map images based on color opponency. In this method, a color-map image is transformed into a color opponent representation as proposed for human vision. The color contrast is enhanced in a manner analogous to the opponent surround receptive fields. The enhancement process separates adjacent foreground and background regions into pairs of opponent colors. The segmentation process can then be easily completed based on this opponent structure. © 1996 John Wiley & Sons, Inc.     

A population balance model describing the dynamics of molecular weight distributions and the structure of PHA copolymer chains

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters produced by many bacterial species under growth-limited conditions when the carbon source is present in excess. It has been recently experimentally demonstrated (Nano Letters 1(9) (2001) 481) that alternating between different carbon sources can lead to the formation of different block copolymer types. This experimental work has been guided by the modeling work presented here as the theoretical considerations permitted evaluation and optimization of the synthesis conditions applied experimentally. To better understand and to optimize the biosynthesis process of different copolymers with desirable properties, we have developed a population balance model that can predict the dynamics of active and inactive PHA polymer chain molecular weight distributions in a nongrowing Ralstonia eutropha cell population. The steady-state version of the model in conjunction with available experimental data was used to compute the steady-state active chain molecular weight distribution and the termination rate as a function of polymer molecular weight for two elongation rate models. For both elongation rate models the steady-state active chain distribution was found to be a monotonically decreasing function of the polymer molecular weight, whereas the termination rate exhibited a maximum. The analytical solution of the steady-state problem was shown to be in excellent agreement with the available experimental data. The population balance model was subsequently used to study the transient dynamics of the process and to predict the experimental conditions, which maximize the production of di- and tri-block copolymer final concentrations. In addition, the structure and molecular weight distribution of the obtained block copolymers were analyzed. Due to the fact that the predicted conditions fall into the range of feasible bioprocessing manipulations, it is expected that such block copolymers can be synthesized. In addition, the proposed model reveals important details of the polymerization process that are difficult to obtain experimentally. Thus, the developed population balance framework should be generally useful for the optimization and control of polymerization processes with similar reaction mechanisms.     

射流稀疏颗粒图像PIV算法应用

颗粒图像测速（particle image velocimetry,简称PIV）是一种非接触式流场测量方法,它具有全场以及对流场无干扰的特点,在流体力学、化工等很多领域均有非常广泛的应用．     

乳液聚合法合成高相对分子质量聚醋酸乙烯酯的研究

采用过硫酸铵/亚硫酸氢钠氧化还原体系低温引发醋酸乙烯酯乳液聚合,合成出分子量为1.07×106、分子量分布为2.75的聚醋酸乙烯酯。讨论了聚合温度、单体用量、十二烷基硫酸钠(SDS)用量、过硫酸铵用量、亚硫酸氢钠用量等因素对聚醋酸乙烯酯黏均分子量的影响,并用GPC法对其进行表征。     

煤基粗油轻质组分定性定量分析现状与展望

煤基粗油是指原煤经各种热化学反应、化工过程加工处理后得到的初级液体产物,包括煤焦油、煤直接液化油和煤间接液化油等。以生产过程全流程物料衡算为约束条件,对煤基粗油全组分组成的准确定性定量分析,不仅可以全面掌握煤基粗油的组成组分性质,而且可实现对煤基粗油的进一步精准加工、提质生产。但由于煤基粗油组分组成的复杂性,不仅难以实现进样组分及分析结果之间的物料衡算,而且也不能最大程度地实现对所有组分的组成及含量的准确分析,至今尚未见到对此内容相关文献资料报道,也没有相应分析方法的国家或行业标准。因此,以物料衡算为约束,建立全面、系统的分析方法,对煤基粗油进行精准定性定量分析是目前亟需解决的问题。本文指出利用气相色谱与红外光谱联用、液相色谱分离后与紫外光谱、同步荧光光谱联用等光谱分析法可快速获得煤基粗油族组分含量的测定,或是对煤基粗油性质做定性的描述;核磁共振波谱法可实现酚类化合物准确的定性、定量;化学分析法仅适合于煤基粗油具体成分的定性定量分析;红外光谱、核磁共振波谱、凝胶渗透色谱和元素分析结合可系统分析与表征煤基粗油及其组分,得到一些重要的物质结构参数信息;色谱分析法可通过色谱的分离功能使复杂混合物分离,并利用各种检测器工作原理的不同来实现定性和定量。其中定性主要采用质谱仪、光谱仪、核磁共振波谱仪等;定量的方法有归一化法、内标法、外标法、响应因子预测法。针对煤基粗油轻质组分（沸点＜350℃）组成的定性定量,气相色谱-质谱联用（GC-MS）技术为此分析过程提供了可能,本文提出并推导了火焰离子化检测仪（FID）响应因子预测公式,将该公式与面积归一化法联用建立FID定量方法体系,加标回收实验（回收率为99.07%,质量分数）表明该方法体系准确、有效,可以被广泛应用于复杂有机混合物的定量分析中,并指出煤基粗油轻质组分定性定量分析过程中的关键在于对复杂混合物中各组分响应因子的准确获得。     

Three-dimensional mathematical modeling of dispersed two-phase flow using class method of population balance in bubble columns

Computational fluid dynamics (CFD) simulations of bubble columns have received recently much attention and several multiphase models have been developed, tested, and validated through comparison with experimental data. In this work, we propose a model for two-phase flows at high phase fractions. The inter-phase forces (drag, lift and virtual mass) with different closure terms are used and coupled with a classes method (CM) for population balance. This in order to predict bubble’s size distribution in the column which results of break-up and coalescence of bubbles. Since these mechanisms result greatly of turbulence, a dispersed k– turbulent model is used.The results are compared to experimental data available from the literature using a mean bubble diameter approach and CM approach and the appropriate formulations for inter-phase forces in order to predict the flow are highlighted.The above models are implemented using the open source package OpenFoam.     

应用降膜理论研究板波纹填料的持液量

采用降膜理论建立了板波纹填料的持液量模型。通过对下降液膜的受力分析 ,给出了有效重力加速度的计算方法。应用该模型对 2 50 Y型填料进行了计算 ,并和实验值进行了比较。对比表明 ,模型计算值与实验值的偏差在工程意义上都是可以接受的 ,因而模型具有一定的应用价值。     

Modifications of carbon for polymer composites and nanocomposites

The various forms of carbon used in composite preparation include mainly carbon-black, carbon nanotubes and nanofibers, graphite and fullerenes. This review presents a detailed literature survey on the various modifications of the carbon nanostructures for nanocomposite preparation focusing upon the works published in the last decade. The modifications of each form of carbon are considered, with a compilation of structure-property relationships of carbon-based polymer nanocomposites. Modifications in both bulk and surface modifications have been reviewed, with comparison of their mechanical, thermal, electrical and barrier properties. A synopsis of the applications of these advanced materials is presented, pointing out gaps to motivate potential research in this field.