Extraction of rice brain oil using supercritical carbon dioxide and propane

Extraction of rice bran lipids was performed using supercritical carbon dioxide (SC−CO₂) and liquid propane. To provide a basis for extraction efficiency, accelerated solvent extraction with hexane was performed at 100°C and 10.34 MPa. Extraction pressure was varied for propane and SC−CO₂ extractions. Also, the role of temperature in SC−CO₂ extraction efficiency was investigated at 45,65, and 85°C. For the SC−CO₂ experiments, extraction efficiencies were proportional to pressure and inversely proportional to temperature, and the maximal yield of oil achieved using SC−CO₂ was 0.222±0.013 kg of oil extracted per kg of rice bran for conditions of 45°C and 35 MPa. The maximal yield achieved with propane was 0.224±0.016 kg of oil per kg of rice bran at 0.76 MPa and ambient temperature. The maximum extraction efficiencies of both SC−CO₂ and propane were found to be significantly different from the hexane extraction baseline yield, which was 0.261±0.005 kg oil extracted per kg of rice bran. A simulated economic analysis was performed on the possibility of using SC−CO₂ and propane extraction technologies to remove oil from rice bran generated in Mississippi. Although the economic analysis was based on the maximal extraction efficiency for each technology, neither process resulted in a positive rate of return on investment.     

Membrane degumming of crude rice bran oil: Pilot plant study

The procedure for the classical chemical refining of vegetable oils consists of degumming, alkali neutralization, bleaching, and deodorization. Conventional refining of rice bran oil using alkali gives oil of acceptable quality, but the refining losses are very high. A critical work has been carried out to study the application of membrane technology in the pretreatment of crude rice bran oil. Oils intended for physical refining should have a low phosphorus content, and this is not readily achievable by the conventional acid/water degumming process. The application of membrane technology for the pretreatment of rice bran oil has been investigated. The process has already been successfully applied to other vegetable oils. Ceramic membranes, which are important from the commercial point of view, were examined for this purpose. The results showed that the membrane‐filtered oils met the requirements of physical refining, with a substantial reduction in color. It was observed that most of the waxy material was also rejected. Experiments were carried out to establish the relationship between permeate flux and rejection with membrane pore size, trans‐membrane pressure and micellar solute concentration.     

中国水稻害虫发生与防治研究进展

本文介绍了我国水稻害虫发生的种类，主要稻虫的种群消长，对水稻危害的损失，在各个不同年代，通过研究和防治，总结出对抗虫品种评价与利用的研究发展迅速，新农药的试验开发效果明显。７０年代以来，按我国稻区生态条件和稻虫为害的特点，形成了江淮、太湖平原、川西平原、洞庭湖平原和珠江三角洲五大稻区的水稻病虫综合防治技术体系，主要技术路线是以农业防治为基础，抗性品种为主体，依靠经济防治指标，协调农药防治和利用天敌     

17.2%苄.哌可湿性粉剂在直播稻田的应用

１７．２％苄．哌可湿性粉剂是近年推出的稻田复配除草剂新品种。通过药剂不同用量、时间试验结果，表明亩用２００－２５０克，在直接稻播后当天至５天内，对水３７．５公斤，喷雾处理，对杂草株、鲜重防效均达９０％以上，基本达到施药一次，控制草害。药剂对水稻安全，无药害产生，因而是目前直播稻田比较理想的除草剂新品种。     

抛秧稻田杂草发生与化除技术研究初报

抛秧田杂草不但种类多，危害重，而且化除难度大，技术要求高，据１９９３－１９９５年的试验、示范结果证明，一般草害田，掌握在抛栽后１０－１５天，每公顷用５０％二氯喹啉酸３７５－４５０克加１０％苄嘧黄隆１５０－２２５克，采用喷雾或毒土法防治一次，对稗草和多种阔叶草的防效一般可稳定在９０－９３％左右，并且可使亩产增加２成左右，但多草田和漏水田，则应通过二次用药或提高药剂用量的方法加以解决。     

直播单季稻田杂草防除试验

田间试验表明，３５％丁草胺－苄嘧黄隆在水稻播种后６天用１５０克／６６７米＾２，１２％Ｈｅ草酮在水稻播种前３天用１５０毫升／６６７米＾２，对直播单季稻田主要杂草千金子、稗草、异型莎草、矮慈姑、节节菜、鸭舌草等均具有显著的防除效果，总草防效分别达９７．３％和９５．６％。根据直播单季稻田杂草分布的具体情况，有选择性地应用丁草胺、哌草丹－苄嘧黄隆、丙草胺、吡嘧黄隆，能收到较好的除草效果。     

Fertilizer inputs, nutrient balance, and soil nutrient-supplying power in intensive, irrigated rice systems. I. Potassium uptake and K balance

Research in many countries indicates a negative K balance in intensive, irrigated rice systems but comparative studies across different environments are few. Using a uniform sampling methodology, we measured K uptake, K use efficiency, and K balance in six different fertilizer treatments of long-term fertility experiments with rice at 11 sites in five Asian countries. Depending on the absolute yield level, K uptake requirements of rice ranged from 17 to 30 kg K per ton of grain. For yields greater than 8 t ha^-1, total K uptake exceeded 200 kg ha^-1. The K balance at most experimental sites was negative, with an average net removal of 34–63 kg K season^-1. There was significant depletion of soil K reserves at many sites. Based on these data, we estimated that the amount of K cycled annually from the soil into rice plants is 7–10 million t in irrigated rice systems of Asia. About 1 million t of this total amount is removed with the harvested grain. Present recommendations for K addition in most intensive irrigated rice domains are insufficient to replace K removal. However, response to K can only be expected on soils with deficient supply capacity and where other nutrients, particularly N and P, are not limiting. Efficient K management for rice must therefore be based on the K input/output balance, the achievable yield target, and the effective K-supplying power of the soil.     

丘陵山区水稻生产全程机械化工程研究

水稻生产的主要环节有耕整地、种植(育秧、栽插、直播)、田间管理(植保、除草)和收获,丘陵山区水稻生产主要环节对机械装备的要求有其特殊要求.文中给出了丘陵山区水稻生产全程机械化机械装备研究的技术路线,同时提出了丘陵山区水稻生产全程机械化的对策.     

基于多光谱成像技术的宣纸形态学特征分析

国画艺术品的科技取证与鉴别受到各领域的关注。宣纸作为国画的重要载体,其特征提取和分析方法有较高的研究意义。本文使用多光谱成像技术对宣纸进行形态学特征分析。实验采用多光谱成像系统获取宣纸在不同波长通道下的光谱图片,继而采用纹理参数统计对光谱图像进行测量,获得宣纸特征的敏感波段;采用数学形态学和灰度统计原理建立宣纸形态学特征分析模型,得到一维特征向量。为了评价特征向量的准确度,实验将特征向量输入到支持向量机（SVM）分类器进行检测分类。结果表明,宣纸的差异化特征在550nrn波段下最为明显;由模型输出的特征向量分类正确率为96％。本文提出的宣纸分析模型能够将大部分种类的宣纸特征准确提取,并具有一定的高效性。     

基于ANSYS Workbench的自走式山地微型水稻联合收割机结构的有限元分析

基于Solidworks软件平台建立自走式山地微型水稻联合收割机机架结构的几何模型,应用有限元分析软件ANSYS Workbench对机架结构进行有限元分析,得出机架结构在承受负载作用时的整体位移和应力分布状态,获取机架应力出现最大值的位置,并用强度校核理论对机架结构的应力分析结果进行了校核,结果表明机架结构的设计符合强度要求。机架某些部位的强度富裕,尚有优化空间。有限元分析结果可为今后机架结构或材料的改进提供参考理论依据。