Kinetics of Dehydration of Green Alfalfa

ABSTRACT

Artificial drying is an important step in processing of green crops in order to preserve their freshness and nutrients for longer time at relatively lower costs. Forage crops, tea and tobacco are the major green crops where the commercial drying is a major operation in their processing. Fresh green alfalfa at about 75 to 80% moisture is subjected to drying in different types of dryers.ln the case of alfalfa, the raw material consists of leaves, stems, chops and fine stems, each varying distinctly in their physical and structural characteristics. The moisture content is reduced from initial level to about 10%. The drying air temperatures range from 40 b 800°C; the lower temperatures are used inconveyor dryers whereas high temperatures are used in rotary drum drycn.The results on drying behavior, and changes in physico-chemical propedes during drying for components of green alfalfa over the temperature range of 40 m 800°C are presented in this paper. The optimum temperature for drying from the stand point of color and protein solubility was found to be 175°C.     

Aerodynamic Separation and Fractional Drying of Alfalfa Leaves and Stems—A Review and New Concept

This article examines the state-of-the art on aerodynamic separation and drying of leaves and stems. Relevant aerodynamic and drying characteristics of alfalfa leaves and stems, important in the design and functional performance evaluation of appropriate drying and separation systems, are presented. General features and design parameters of rotary drum dryers are discussed. A new efficient approach to combined drying and separation in a rotary drum dryer is described in which fresh or pre-wilted alfalfa mixture is dried at a moderate temperature, and in the same operation the dry leaf fraction is aerodynamically separated from the stem fraction. Preliminary test data obtained from the dryer indicated that the separated product stream had comparatively high leaf purity, confirming the feasibility of the new approach.     

在非等温条件下石膏和硼石膏的加热脱水动力学研究

Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides.     

不同品种及单株木豆叶蛋白质含量的研究

对云南省元阳县水塘试验点种植的22个品种(包括引进品种及国内品种)、3个采收季节及其中两个品种不同单株的木豆叶进行蛋白质含量分析测定,结果表明:蛋白质含量与品种呈显著性差异,与采收季节及单株呈极显著差异。不同品种间蛋白质含量为17.65%～22.43%;不同季节间蛋白质含量为14.78%～23.97%。Y57-5和Y43适合作为蛋白饲料源推广种植,其最佳采收期为秋季。为避免异交,保持品种优良性状,对选定优良单株最好在开花前套上防虫纱袋。     

氟橡胶F2314黏结剂的热分解动力学

根据F2314黏结剂在升温速率分别为5,10,20K／min时的DSC-TG曲线,在20～500C温度范围内对F2314黏结剂的热分解过程进行了研究,用Coats-Redfern方法获得F2314黏结剂的热分解动力学参数和机理函数。结果表明,在不同升温速率的TG曲线上,F2314黏结剂热失重的起始温度大致相同,而结束温度随升温速率的增大而升高。同时,升温速率为10K／min的DSC曲线由一个熔化吸热峰和一个分解放热峰组成,在低于360℃时具有良好的热稳定性。得到F2314黏结剂热分解的活化能为294．76kJ／mol,指前因子为10^21.62s^-1,机理函数为f（α）=（1-α）^3/4。     

油酸甲酯和硬脂酸甲酯热解特性及动力学研究

通过热重分析仪对油酸甲酯和硬脂酸甲酯的热解特性进行了研究,发现油酸甲酯相变硬脂酸甲酯具有较差的热安定性。在升温速率分别为10、15、20、30℃/min条件下,利用TG-DTG曲线分析了它们的基本热解特性。结果表明,随着升温速率的增加,它们的起始热分解温度、最大失重速率、最大失重速率峰值温度以及其他热分解参数均呈增大趋势。同时,用多元线性回归法求得相应的反应级数、活化能和指前因子,发现油酸甲酯和硬脂酸甲酯的热解反应机理函数不同,且反应活化能和指前因子之间表现出较好的动力学补偿效应。     

LLM-105基PBX炸药的热分解反应动力学

通过布氏压力计法获得了普通的和纳米化的LLM-105基PBX炸药在不同温度条件下热分解放气量随时间的变化曲线。基于Arrhenius公式计算了两种PBX炸药分解深度为0.1%时的表观活化能。采用TG-DSC研究了两种LLM-105基PBX炸药的非等温热分解反应动力学。结果表明,由Arrhenius公式得到的普通和纳米化的LLM-105基PBX炸药在分解深度为0.1%时的表观活化能分别为74.67和138.09kJ/mol。利用Kissinger法计算获得两种LLM-105基PBX炸药在最大分解速率(分解深度约50%)下的表观活化能分别为389.26和215.73kJ/mol,与Ozawa法计算结果相吻合。升温速率趋于零时的特征分解峰值温度分别为606.94和586.48K,热爆炸临界温度分别为615.0和600.4K。相对于普通LLM-105基PBX炸药,纳米化LLM-105基PBX炸药热分解具有更高的反应活性,热感度也有所提高。     

2,6-二氨基-3,5-二硝基吡啶-1-氧化物及其黏结炸药的热分解动力学

在升温速率分别为2.5、5、10、20 K/min条件下对2,6-二氨基-3,5-二硝基吡啶-1-氧化物(ANPyO)及其黏结炸药进行了TG实验,根据实验结果讨论了ANPyO及其两种橡胶黏结炸药的热分解过程,用非线性等转化率积分法和Ozawa法计算了ANPyO及其两种黏结炸药的热分解动力学参数和机理函数.结果表明,ANPyO及其黏结炸药在210℃以下均未出现明显的质量损失过程.ANPyO及其黏结炸药的热分解机理均属于n=1的随机成核和随后生长.ANPyO热分解的活化能、指前因子和机理函数分别为198.22 kJ/mol,2.743×1017 s-1,f(a)=(1-α),热分解动力学方程为:(dα)/(dt)=kf(α)=A·e(-E)/(RT)·f(α)=2.743×1017×(1-α)exp-(2.384×104)/(T).     

预处理稻壳及其与杨树锯末掺混燃烧特性和燃烧动力学分析

采用热重技术对稻壳（DK）和杨树锯末（JM）燃烧进行分析,考察了不同预处理方式对稻壳燃烧特性的影响,并研究了不同升温速率及稻壳和杨树锯末掺混质量比对掺混燃烧特性及燃烧动力学的影响。结果表明：水洗及酸洗可使稻壳燃烧TG-DTG热重曲线向高温区移动,最大失重速率及对应失重温度升高。水洗使稻壳综合燃烧特性指数提高2.5×10^-7~5.9×10^-7%/（min²·℃³）,而酸洗使稻壳综合燃烧特性指数下降11×10^-7~11.9×10^-7%/（min²·℃³）。不同预处理后稻壳在挥发分析出燃烧阶段的活化能高于未处理稻壳,酸洗后稻壳焦炭燃烧阶段活化能降低16.94 kJ/mol,而水洗使稻壳焦炭燃烧阶段活化能升高。提高稻壳添加比例,混合燃料着火温度和燃尽温度降低。随着升温速率的提高,混合样品综合燃烧特性指数和残余率升高。70%稻壳和30%杨树锯末混合燃料在升温速率40℃/min下燃烧产生协同效应。     

Removal of cellulose from sunflower meal by fractionation

The dependence of sunflower meal fractionation on the following factors was investigated: quality of original meals, 37.5%, 40.0% and 42.5% crude protein; screen hole size, 1.5 mm, 2.0 mm, 2.5 mm and 3.0 mm; and single-phase and two-phase fractionation. The following conclusions were drawn. The increased protein levels in original meals (from 37.5% to 42.5% crude protein) had considerably greater effects on the quality than on the yield of the protein fractions. Increased screen hole size (from 1.5 mm to 2.5 mm) increased the yield of the protein fractions by 16.4–22.3%, but reduced the protein level in these fractions by 2.3–2.8%. Two-phase fractionation of the original meals with 40.0% and 42.5% crude protein increased the protein yield in the resulting protein fractions by 15.5–22.8%. The most efficient fractionation procedures rendered high yields of attractive protein fractions that contained 44.0–47.5% crude protein. The protein fractions were analyzed for physico-functional constants and amino acid composition. The most efficient and applicable fractionation procedures, those that may be successfully used in oil refineries, were selected.     

高温复合隔热结构组成对其瞬态热特性的影响

建立多层复合隔热结构辐射-导热与相变换热模型, 采用Monte Corlo方法模拟复合隔热结构内半透明介质的热辐射传递,有限体积法求解能量方程。分析比较了纤维隔热毡-金属膜复合结构、纤维隔热毡-纤维增强气凝胶材料-金属膜复合结构、纤维隔热毡-纤维增强气凝胶材料-相变隔热材料-金属膜复合结构等三类典型复合隔热结构的瞬态换热特性,研究表明不同的复合隔热结构组成其热特性差异显著,为复合隔热结构的设计、优化提供了指导思路。     

Improvement of the Fluorescence Intensity during a Flow Cytometric Analysis for Rice Protoplasts by Localization of a Green Fluorescent Protein into Chloroplasts

Protoplasts have been a useful unicellular system for various molecular biological analyses based on transient expression and single cell analysis using fluorescence-activated cell sorting (FACS), widely used as a powerful method in functional genomics. Despite the versatility of these methods, some limits based on low fluorescence intensity of a flow cytometric analysis (FCA) using protoplasts have been reported. In this study, the chloroplast targeting of fluorescent proteins (FPs) led to an eight-fold increase in fluorescence intensity and a 4.5-fold increase of transfection ratio from 14.7% to 65.7% as compared with their targeting into the cytoplasm. Moreover, the plot data of FCA shows that 83.3% of the K-sGFP population is under the threshold level, regarded as a non-transgenic population with background signals, while 65.7% of the K-sGFP population is spread on overall intervals. To investigate the reason underlying this finding, mRNA/protein levels and transfection efficiency were analyzed, and results suggest that mRNA/protein levels and transfection ratio are not much different between K-sGFP and KR-sGFP. From those results, we hypothesized that the difference of fluorescence intensity is not only derived from cellular events such as molecular level or transfection efficiency. Taken together, we suggest that the translocation of FPs into chloroplasts contributes to the improvement of fluorescence intensity in FCA and, apparently, plays an important role in minimizing the loss of the transfected population. Our study could be usefully applicable for highly sensitive FACS and FCA-investigations of green tissue.     

Impact of Wisteria floribunda Agglutinin-Positive Mac-2-Binding Protein in Patients with Hepatitis C Virus-Related Compensated Liver Cirrhosis

We aimed to examine the effect of Wisteria floribunda agglutinin-positive Mac-2-binding protein (WFA⁺-M2BP) level on survival comparing with other laboratory liver fibrosis markers in hepatitis C virus (HCV)-related compensated liver cirrhosis (LC) (n = 165). For assessing prognostic performance of continuous fibrosis markers, we adapted time-dependent receiver operating characteristics (ROC) curves for clinical outcome. In time-dependent ROC analysis, annual area under the ROCs (AUROCs) were plotted. We also calculated the total sum of AUROCs in all time-points (TAAT score) in each fibrosis marker. WFA⁺-M2BP value ranged from 0.66 cutoff index (COI) to 19.95 COI (median value, 5.29 COI). Using ROC analysis for survival, the optimal cutoff point for WFA⁺-M2BP was 6.15 COI (AUROC = 0.79348, sensitivity = 80.0%, specificity = 74.78%). The cumulative five-year survival rate in patients with WFA⁺-M2BP ≥ 6.15 COI (n = 69) was 43.99%, while that in patients with WFA⁺-M2BP < 6.15 COI (n = 96) was 88.40% (p < 0.0001). In the multivariate analysis, absence of hepatocellular carcinoma (p = 0.0008), WFA⁺-M2BP < 6.15 COI (p = 0.0132), achievement of sustained virological response (p < 0.0001) and des-γ-carboxy prothrombin < 41 mAU/mL (p = 0.0018) were significant favorable predictors linked to survival. In time-dependent ROC analysis in all cases, WFA⁺-M2BP had the highest TAAT score among liver fibrosis markers. In conclusion, WFA⁺-M2BP can be a useful predictor in HCV-related compensated LC.