CONDUCTIVE DRYlNG CHARACTERISTICS OF GELATINIZED RICE STARCH

The main objective of the experiment in thispaper is to investigate the influence of the ratio of the thickness of the plate and that of the film, and initial condi- tions on the conductive drying characteristics of thin films of gelatinized rice starch on a hot plate under constant heat and mass transfer to the surroundings. The plate was. supported on one arm of a sensitive balance which measured and recorded the weight loss due to drying. Tbennocouples situated at the upper and lower surfaces of the plate recorded the respective temperatures. The gelatinized starch was prepared by cooking a slurry of rice starchin a heated and agitated vessel at slightly above the gelatinization temperatureof the starch 70C. The film was applied after the plate was heated to its initial temperature which ranged from 70C to 119C. The weight 10s and the temperature of the upper and lower surfaces of the plate were recorded. The m3isture content of the dried sample was determined by measuring the weight loss after heating it in an oven at 90C for 24 hours.The dimensionless average moisture content was fitted to the drying rate eauation of the form The dimensionless temperature of tbe filmplate interface data was fitted to the following equation It was found that the critlcal moisture content Xc increases when both the intial temperature level and the ratio of the thickness of the plate to that of the film are raised. The dimensionless avenge moisture content profiles against dimensionless time and the dimensionless drying rate ploti against the dimensionless moisture content are not affected at all by this ratio. There was an initial cooling period fol lowed by a continuous rue in temperature. The dimensionless temperature is independent of the ratio of the thickness of rbe plate to that of the film. The dimen     

CONDUCTIVE DRIlNG CHARACTERISTICS OF GELATINIZED RICE STARCH

ABSTRACT

The drying mechanism of shaped ceramics is reviewed and some methods for eliminating defects produced by drying are discussed in this report. The types of defects depend upon the shaping method, shape, properties of the raw materials, drying process and other items. Most defects of dried ceramics are produced during the initial or middle drying stage when large shrinkage of the ceramic body occurs. These defects may be successfully eliminated by heating the body from the inside. Self-deformation caused by weight is also a serious defect. The near net shaping of fine ceramics to reduce machining requires uniform body shrinkage and hence, highly controlled drying. Examples of electric current drying, dielectric drying, and dewaxing are also shown in this report.     

MOISTURE SORPTION CHARACTERISTICS OF STARCH MATERIALS

ABSTRACT

An understanding of the sorptional equilibrium of food systems is an important objective in food engineering. In particular, a knowledge of the equilibrium characteristics of foodstuffs is an essential prerequisite for interpretation of the mass transport phenomena during drying. The equilibrium moisture content of a food system is developed as a result of the interaction between the material and the environment. A standard static gravimetric technique was adopted to evaluate the moisture sorption characteristics of the model food gels. The high-starch systems displayed Type II isotherm characteristics, while the high-sugar systems presented Type III behaviour. Adequate quantitative evaluation of the sorption characteristics was realized on the basis of the Guggenheim-Anderson-de Boer model.     

世界导电塑料工业化进展

介绍了用于导电塑料制造的新型导电添加剂如导电炭黑、碳纳米管、导电钛酸钾晶须、纳米石墨微片等的工业化开发与应用。重点综述了具有高性能特殊用途的导电塑料品种、本征导电型及离子导电型塑料合金技术、母料技术等的工业化进展。列举出许多国际知名厂商的相关新产品牌号,为导电塑料新产品开发提供参考。     

导电高分子材料的研究概况

综合介绍了导电聚合物的种类及其合成的方法，列举了导电聚合物在不同领域的应用情况，同时对导电聚合物未来的发展提出了一些看法。     

导电塑料概述

概述了导电塑料的发展状况，对其分类情况，应用领域，导电机理及制备工艺进行了阐述，并介绍了导电塑料的最新进展及动向。     

导电聚合物复合材料的发展

综述了有关导电聚合物复合材料的研究。讨论了不同导电聚合物复合材料的导电性、光学特性、电化学特性、力学性能以及它们的不同结构形貌。分析了复合材料制备工艺对其结构及性能的影响。     

聚丙烯/炭黑导电复合材料的发热特性及非欧姆性质研究

探索了聚丙烯／炭黑导电复合材料在不同的通电状态及不同的工艺条件下的电压—电流特性、正温度系数效应及起动态性能。结果表明，炭黑的种类、添充量及添加剂将改变复合材料的发热特性。并且聚丙烯／炭黑导电复合材料的非欧姆性质明显。     

导电云母粉的制法及其应用

导电涂料和塑料用导电云母粉具有比重小、导电性好、有光泽、颜色可调、原料丰富、价格低等特点,优于其他导电填料,用于防止产生静电和屏蔽电磁波。介绍了化学镀和化学共沉淀两种方法制备导电云母粉。举例说明导电云母粉的应用。     

涂料用导电玻璃纤维填料的制备

采用化学镀方法在玻璃纤维上沉积金属镀层,制得镀金属的导电玻璃纤维,用作导电涂料的填料。简述镀镍－磷、镀铜－磷和镀镍－铜－磷玻璃纤维的工艺流程。讨论了化学镀的反应条件对导电玻璃纤维性能的影响。     

导电聚合物复合材料技术进展

本文介绍了导电聚合物复合材料的种类及其特性,重点讨论了填充和共混型导电聚合物复合材料的制备方法、研究现状及最新进展,并且展望了它们的发展方向和应用前景。     

PERFORMANCE CHARACTERISTICS OF A CERAMIC MEMBRANE SYSTEM FOR MICROFILTRATION OF CORN STARCH HYDROLYSATE

A ceramic microfiltration membrane was used for the clarification of corn starch hydrolysate, having a dextrose equivalence of 95, to study the effect of process variables (transmembrane pressure, cross-flow velocity, and feed concentration) on permeate flux. Flux increased with increased cross-flow velocity for all transmembrane pressures and feed concentrations up to a volume concentration ratio of 100. Flux became asymptotic at pressures of 200-375kPa, indicating that microfiltration performance was limited by concentration-polarization. The optimum transmembrane pressure was higher at higher cross-flow velocities. A process model based on the resistances-in-series concept adequately described the observed variation of permeate flux with process variables such as transmembrane pressure, cross-flow velocity and feed concentration. Resistance due to concentration polarization decreased linearly with increase in cross-flow velocities for all feed concentrations, while fouling resistance increased linearly with increase in feed concentration.     

片状导电珠光颜料的现状与发展

综述了近年来国内外的一种新型导电颜料————片状导电珠光颜料的现状及发展情况。介绍了片状导电珠光颜料的特点、分类、导电机理与制备方法,以及今后的研究和开发方向。     

羧甲基淀粉钠的合成

本文是用小麦粗淀粉、氯乙酸为原料,以醇为介质,以氢氧化钠水溶液为酸接受剂,经羧甲基化作用制得粒状能溶于冷水的羧甲基淀粉钠。     

导电涤纶的试制

用碘吸附 -铜离子络合工艺制得比电阻为 8× 10 3～ 1.5× 10 4 Ω· cm的导电涤纶 POY长丝。讨论了诸多因素对纤维比电阻的影响 ,通过实验选定了最佳工艺条件。碘吸附过程的最佳工艺条件为 :I/KI质量比 1.5～ 1.8,碘浓度 2 10 g/L,温度 70～ 80℃ ,时间 80 min;铜离子络合最佳工艺为 :Cu Cl/NH4 Cl质量比 0 .6 ,Cu Cl浓度 2 0～ 4 0 g/L,温度 85～ 95℃ ,时间 4 0 min     

聚合填充型导电聚乙烯复合料的制备及其性能

介绍了制备聚烯烃复合料的新工艺———聚合填充法及其在制备导电聚烯烃复合料方面的发展近况 ,并采用此工艺制备了导电聚乙烯复合料。研究表明 ,用导电填料制备导电聚乙烯的适宜温度为 40℃ ,压力为 0 6MPa。随着导电填料的增加 ,复合料的导电性提高 ,但力学性能有所下降     

复合型导电塑料制备方法的研究进展

阐述了近年来复合型导电塑料制备方法,包括表面处理法、填料分散复合法、分散相的层状分散技术法及导电填料层积复合法,并展望了复合型导电塑料的发展及应用前景.     

丙烯酸聚氨酯涂料的研制

采用多羟基丙烯酸树脂作为羟基组分,ＨＤＩ缩二脲多异氰酸酯作为固化剂,配制成丙烯酸聚氨酯摩托车涂料。该涂料既保持了丙烯酸涂料优异的硬度、丰满度、光泽、耐候性和耐化学品性,又具有良好的附着力、柔韧性和耐磨性。介绍了该涂料的配方及其配制。比较了几种摩托车涂料的性能。讨论了涂料用原料的选择     

明快色调的导电云母颜料

以德国默克公司的导电云母颜料产品为例,介绍了导电云母颜料的结构与性能,以及在导电涂料中的应用