Studies on fissure caused by moisture adsorptio in rough rice

1995年的实验使用了一个微型CCD相机，安装在一个空气烘箱内，温度和湿度控制是在科学研究资助计划下购买的。用所述摄像机记录了糙米粒在吸附环境中的断裂行为。录像带被重播，并在电视屏幕上确定了裂缝开始和发展的确切时间。烘箱内的空气条件分别为80、85、90和95%湿度，温度分别为10、20和30ºC。在各温度水平和85% RH以上，17.3%水分条件下无裂缝发生，15.3%水分条件下裂缝发生较少，过干（12.7%水分）裂缝发生最多，过干（10.7%水分）裂缝发生最多。大多数过干颗粒在干燥开始后1 ~ 2小时，中部突然裂开，并迅速向外侧延伸。裂缝的成因在1996年的实验中使用了相同的烤箱。在解吸过程中，从40°C及以上开始出现裂隙。在接近饱和空气条件下，湿度为20.2%时，颗粒未发生裂缝，而随着初始含水量的降低，裂缝的发生率增加，在所有温度水平下，过干颗粒（湿度为12.7%）的裂缝发生率均较高。得到了10、20、30和40个浓度的吸附等温线，得到了相对湿度为40 ~ 95%时的平衡含水率。结果讨论了裂纹与颗粒膨胀收缩、解吸吸附速率和吸附电位的关系。水稻的胀缩比和横向纵向比在弹性体中是独特的。水蒸气压的差异引起了吸附和解吸。驱动力是吸附势，吸附势取决于湿度。

Experiments in 1995 utilized a microscopic CCD camera set inside an air oven with temperature and humidity controls purchased under the grant-in-aid program for scientific research. The fissuring behavior of a brown rice kernel in an adsorptive environment was recorded in a video-casette tape using the said camera. The video tape was replayd and on a TV screen the exact time when fissure started and developed was determined. Air conditions in the oven were varied at 80,85,90 and 95% humidity and temperatures of 10,20, and 30ﾟC.The occurrence of fissure were : none in grain with 17.3% moisture, few in grain with 15.3% moisture at 30ﾟC-95% RH,great in overdried grain (12.7% moisture), and greatest in excessively dried grain (10.7% moisture) at all temperature levels and above 85% RH.Majority of overdried grains suddenly fissured in the central part and rapidly extend to the outer part after 1 to 2 hours from the start of drying.The cause of fissure were done using the same oven in the 1996 experiments. In desorption, fissure occurred from 40ﾟC and above. In adsorption when grains were exposed to near saturated air, fissure did not occur in grains with 20.2% moisture, while the rate of occurrence increased with a decrease in initial moisture content, and heavy occurrence in overdried grains (12.7% moisture) at all temperature levels. Adsorption isotherms for 10,20,30 and 40ﾟC were drawn from which grain equilibrium moisture content were given at 40 to 95% RH.The results discussed the relationship of fissuring to : grain expansion and contraction, rate of desorption and adsorption, and adsorption potential. Rice expansion-contraction and lateral-longitudinal ratios were unique among elastic bodies. Adsorption and desorption were caused by the difference in water vapor pressure. The driving force is the adsorption potential which depends on humidity.