Improved method for prediction of milled rice moisture content based on Weibull distribution

The loss on drying method,which is regarded as the standard method of rice moisture content analysis,provides the most reliable results but is both labor intensive and time consuming.In order to improve the detection efficiency of the loss on drying method,this study investigated the drying characteristics of milled rice and developed an information fusion algorithm with which to predict milled rice moisture content based on the Weibull distribution and Levenberg-Marquardt(LM)algorithm.Application of the Weibull distribution model was investigated regarding its description of the drying kinetics of milled rice during infrared drying.An adaptive mechanism was applied to algorithm design,with the starting point of the estimation algorithm determined by calculating the drying rate at each measuring point,and the end-point distinguished using a two-level threshold algorithm.The calculated results were then compared with the measured data regarding the infrared drying of milled rice.For milled rice samples varying in moisture content from 14.44%-17.67%(dry basis),the relative error between predicted and observed values ranged 0.0037-0.0589,with a reduction in test time of 50.71%-67.87%.

Differences in breaking behavior of rice leaves under microwave and naturally drying processes

In order to fight for good farming time or harvest in bad weather,combine harvester will produce more broken leaves when threshing high moisture content rice,which will seriously hinder the grain cleaning effect.In this study,the breaking behavior of rice leaves under different microwave drying time and drying power was studied.Firstly,based on the appearance of freshly rice leaves undergoing microwave drying,the changing property of moisture content,weightlessness rate and temperature rise of rice leaves were tested and analyzed.Secondly,the tensile breaking force of freshly rice leaves under different microwave drying time and drying power was tested and compared with the tensile breaking force of naturally dried rice.Finally,the optimal microwaves parameters of rice leaves after drying which could result in greater breaking force than the natural drying state were obtained.The result showed that microwave drying method will reduce the moisture content of rice leaves and change the microstructure,which would affect the tensile-breaking property of rice leaves.The maximum tensile breaking force of rice leaves appeared at microwave dried power 70 W for 5-8 min and at microwave dried power 210 W for 3-4 min.The tensile breaking property of rice leaves at microwave dried power 350 W for 6-8 min were the weakest,which was lower than that of fresh rice leaves.Therefore,the optimal microwave drying parameters of rice leaves will provide a basis for the application of microwave technology in the threshing process.

The Sorption Isosteric Heats of Rough Rice in China

Equilibrium moisture content （EMC） data for rough rice of thirteen Chinese varieties were obtained by static gravimetric method at five different temperatures （10, 20, 25, 30, and 35 ℃） and 11% to 96% equilibrium relative humidity （ERH）. Six models, i.e., Brunauer-Emmett-Teller, Guggenheim-Anderson-deBoer, Modified Chung-Pfost （MCPE）, Modified Henderson, Modified Oswin, and Strohman-Yoerger （STYE） fitted the EMC/ERH data based on the coefficient of determination, residue sum-of-squares, standard error of estimate, and mean relative percent error. The best fitted equations were MCPE and STYE, but MCPE is three-parameter, readily transformed equation and adopted in this study. The isosteric heats for both rough rice desorption and adsorption, and for both the sorption of Japonica and Indica rice, decreased rapidly with an increase in seed moisture content （m.c.） until the m.c. of 20% dry basis （d.b.） reached, and thereafter they decreased smoothly with increasing moisture content. The isosteric heats of rough rice desorption were higher than those of adsorption below the m.c. of 22.5% d.b., but thereafter, there was no significant difference found between desorption and adsorption. The sorption isosteric heats of Indica rice were slightly higher than those of Japonica rice under all moisture contents at a constant temperature. These results provide a sound basis for future work on the drying and storage of rice.

Performance evaluation of cement-stabilized pond ash-rice husk ashclay mixture as a highway construction material

This paper reports the results of an investigation carried out on clay soil stabilized with pond ash(PA),rice husk ash(RHA) and cement. Modified Proctor compaction tests were performed in order to investigate the compaction behavior of clay, and California bearing ratio(CBR) tests were performed to determine the strength characteristics of clay. For evaluation purpose, the specimens containing different amounts of admixtures were prepared. Clay was replaced with PA and RHA at a dosage of 30%e45% and5%e20%, respectively. The influence of stabilizer types and dosages on mechanical properties of clay was evaluated. In order to study the surface morphology and crystallization characteristics of the soil samples, scanning electron microscopy(SEM) and X-ray diffraction(XRD) analyses were carried out,respectively. The results obtained indicated a decrease in the maximum dry density(MDD) and a simultaneous increase in the optimum moisture content(OMC) with the addition of PA and RHA.Multiple linear regression analysis(MLRA) showed that the predicted values of CBR tests are in good agreement with the experimental values. Developed stabilized soil mixtures showed satisfactory strength and can be used for construction of embankments and stabilization of sub-grade soil. The use of locally available soils, PA, RHA, and cement in the production of stabilized soils for such applications can provide sustainability for the local construction industry.

含水量不同的籼稻在不同储藏温度下品质变化研究

在5℃、20℃、30℃、40℃四种储藏温度下和调质保湿密封恒温与自然通风恒温两种储藏状态的环境条件下,分别对水分为13.0%、14.0%、15.0%左右(±0.1%)的“鄂香1号”、“二优培九”、“汕优63”三个不同优劣品种的籼稻谷进行为期2个月的实验室模拟储藏试验,每间隔10天对其脂肪酸值、粘度、发芽率等进行测定,实验结果表明:稻谷品种越优,含水量越大,储藏温度越高,其储藏品质劣变率和劣变速率越大。相比而言,稻谷含水量在14.0%以下,储藏环境温度在20℃以下,品质下降变化较小。

烘干设备干燥效率比较及对稻谷爆腰率的影响

对四川省内9个粮食烘干机用户的11台不同型号设备进行调研,通过干燥效率和稻谷爆腰率增值两个指标,对烘干设备在籼稻干燥过程中的应用情况进行综合评价,发现5号、7号和8号烘干设备的干燥效率均远高于100kg/h,且稻谷爆腰率增值均低于10%。其中5号和8号设备是国产品牌,7号设备是进口品牌。另外,5号、7号和8号烘干设备的容量分别为30t、16.5t和10t,可以满足不同用户的需求。

低温下土壤水分对籼稻及粳稻根系生长的影响

用籼稻品种浙 92 48,湘早籼 2 4号和粳稻品种胆振早稻 ,早雪 ,探讨低温及不同土壤水分条件下水稻根系生长及与根系活性变化的关系 .结果如下 :低温下籼稻品种湿润处理的增加根数、种子根伸长量、种子根的一次侧根、粗大一次分枝根增加数以及根系伤流量优于淹水区 ,并且籼稻品种少于粳稻品种 ,根系生理活性的大小与根的生长量具有密切关系 .恢复常温后的增加根数、剪根移栽后的发根数、伤流量的恢复程度也以湿润处理的为优 ,这与低温时根的生长及伤流量的变化有密切的对应关系 .认为在根的生长界限温度条件下 ,由于湿润处理增加了分枝根的数量 ,特别是粗大分枝根的数量 ,提高了根的生理活性维持能力 ,这与低温处理后生长恢复的优势密切相关 .

浸泡对早籼稻水分含量及蒸谷米品质的影响

以早籼稻为对象,通过改变浸泡时间和温度,测定分析浸泡条件对早籼稻的水分含量、蒸谷米VB1的含量以及蒸谷米品质的影响。结果显示,浸泡条件对蒸谷米品质影响明显,当浸泡温度为75℃、时间为3.5 h时,蒸谷米的品质最好,VB1含量最高。

Design,construction and performance evaluation of paddy rice solar drum dryer equipped with perforated drum

A solar drum dryer was designed and constructed for paddy drying,including a fixed outer drum and inner perforated drum,which rotated at the desired rotational speed inside the outer drum.The maximum capacity of the dryer was 10000 g.The rotational speed of the inner drum was controlled.The thermal energy required for the dryer was provided by a solar absorber plate.The dryer per-formance was examined at three levels of rotational speed(0.21,0.42 and 0.84 r.p.m.),drum slope(1°,1.5°and 2°)and air velocity(1.7,1.8 and 1.9 m.s^(-1)).The diameter of the drum was the geometrical parameter that affected the movement of the particles and the ratio of the particle diameter to the drum diameter changed with the change in the drum diameter.Therefore,increasing the diameter of the drum caused a reduction in the repose angle of the paddy without any effect on the filling angle.The displacement of the product along the drum increased with increasing slope and rotational speed.At the lowest air velocity,the time required to remove moisture(<13%)was less.The results showed a significant reduction in cracked brown rice for the paddy dried by the drum dryer at 43-46℃ compared with those dried using a batch dryer.The highest stress-cracking index(11)was observed for the paddy with an initial moisture of 16%.The results showed that for proportional final moisture content,a longer drum should be considered to intensify the slope and rotational speed of the inner drum.

储藏条件与优质籼稻品质变化关系的研究

为探究储藏条件与优质籼稻品质变化的关系,将优质籼稻“丰优22”样品在4种储藏温度(15、20、25和30℃)、3种水分含量(13.5%、14.5%和15.5%)和2种气体成分(氮气、空气)条件下模拟储藏360 d,定期测定其黄粒米含量、发芽率、电导率、α-淀粉酶活性、脂肪酸值、胶稠度、直链淀粉含量、米汤固形物、碘蓝值和米饭硬度、米饭黏度、米饭平衡度、米饭弹性、外观评分、口感评分、综合评分等指标。结果表明,储藏温度越高、水分含量越大,品质变化越明显;在储藏温度、水分含量相同的情况下,氮气储藏具有延缓品质变化的作用。采用主成分分析法对16个指标进行分析,通过降维得到5个累积贡献率达到81.055%的主成分因子,对各主成分中正特征值较大的指标进行筛选,获得发芽率、电导率、碘蓝值和直链淀粉含量等具有代表性的品质特征指标。将4个特征指标与储藏温度、水分含量、气体成分进行相关性分析,发现储藏温度对优质籼稻特征指标影响最大,水分含量影响次之,气体成分影响最小。

鄂中地区偏高水分晚籼稻谷安全度夏试验

利用机械通风结合粮面稻壳压盖控温技术,进行了偏高水分晚籼稻谷保水度夏试验。结果表明,试验仓稻谷水分下降了0.5%,比对照仓水分少下降0.5%;粮食平均温度保持在准低温线以内,延缓了粮食品质陈化,确保了储粮安全。

高水分晚籼稻仓内控湿降水试验

通过用管道将除湿机与高大平房仓相连,采用控温控湿的空气对高水分晚籼稻进行内循环降水,结果表明,此方法可在较短时间内将高水分晚籼稻的整仓平均水分从15.1%降低到13.2%。当环境温度高于23℃,降水速度显著增加。采用除湿机通风降水,每吨稻谷降水1%仅需3.64元,远低于整晒或烘干降水的费用,可在较低成本下达到快速降水的目的。

高水分籼米安全储藏及保鲜技术研究

以一定条件下的籼米平衡水分，水活度作为评价籼米储藏稳定性和制定保 管技术措施及管理规范的重要依据。对不同水分的籼米，综合运用通风储藏、自然低温 隔湿保冷储藏、磷化铝低剂量密闭和间歇密闭及其它储粮技术，使２１７１０ｔ水分为 １３．７％～１６．６％的籼米保质、保鲜、安全储藏６～８个月。３种不同水分的籼米品质变化 趋势、保质保鲜效果均无明显差异。