地热农副产品干燥装置的设计和中间试验

本文根据干燥过程的理论分析和试验研究结果,提出了热风式干燥器设计参数的选择原则,给出一套有一定参考价值的干燥系统的计算方法。该方法概念清楚,不必计算废气排热损失,简化了计算过程。依此,我们设计制造了一套地热干燥中间试验装置,它利用60～70℃的地热水作热源,一次可投湿物料200kg,对于像白菜这类初含水率在90％以上的物料,其每小时最大干燥脱水量超过30kg,平均热效率达到53％。试验结果表明:只有当物料的含水率在90％以上,且表面结合水多的情况下,实际过程才会出现等速干燥阶段。     

Comparison of the adsorption of maize root mucilage and polygalacturonic acid on montmorillonite homoionic to divalent lead and cadmium

Summary Root mucilage material (RM) was isolated from maize plants grown in the field, and its affinity to montmorillonite (M) homoionic to Pb²⁺ and Cd²⁺ was compared with that of a commercial polygalacturonic acid (PGA). Adsorption isotherms of the commercial and natural materials on the two clay systems were compared in unbuffered systems at pH 3 and pH 6. Adsorption of PGA occurred only at pH 3, and was higher on M-Pb than on M-Cd. In contrast, the adsorption of RM was higher on M-Cd than on M-Pb. Total amounts of RM adsorbed at pH 3 were about 3 times lower on M-Cd and 20 times lower on M-Pb than the respective amounts of PGA adsorbed at the same pH. Polygalacturonic acid had a high content of relatively well dissociated (pKa = 3.5) carboxylic groups, and adsorbed on the clay surface at pH values lower than its pKa. At pH 6, the dissociation of the acid groups favoured its solubility, and the metal cations were then probably displaced by ion exchange. The lower affinity of RM to the clay materials was related to its average molecular weight, which was lower than that of PGA, and to its water solubility, which was higher than that of PGA. The low pH dependence of the adsorption of RM was related to its lower carboxylic acidity and higher content in hydroxyl and amino groups.     

The Remobilization of Metals from Iron Oxides and Sediments by Metal-EDTA Complexes

Synthetic chelating agents such as EDTA form strong complexes with heavy metals and therefore have the potential to remobilize metals from sediments and aquifers. In natural waters EDTA is present almost exclusively in the form of metal-complexes. Therefore, remobilization of metals is always a metal-metal-EDTA exchange reaction. We have investigated, to our knowledge for the first time, the remobilization of metals from the surface of synthetic iron oxides and from a river sediment by different metal-EDTA complexes. The metals are exchanged as follows:MeEDTA_dissolved + Me^ast _adsorbed Me^astEDTA_dissolved + Me_adsorbed The order of the remobilization rate of Zn²⁺ from goethite is CaEDTA > Fe(III)EDTA, reflecting the slow exchange reaction of Fe(III)EDTA. For the remobilization of Pb²⁺ from goethite, the rate was found to be Fe(III)EDTA > CaEDTA > ZnEDTA. Here, Fe(III)EDTA has surprisingly the fastest exchange rate. Only very limited remobilization of Pb²⁺ is possible from hydrous ferric oxide at pH 8 due to the very strong adsorption of Pb²⁺. The order of remobilization of Zn²⁺ from a natural river sediment was found to be CaEDTA > CuEDTA > Fe(III)EDTA. The remobilization rate of Zn²⁺ with Fe(III)EDTA is only 12% of the rate with CaEDTA, illustrating the importance of EDTA speciation for assessing remobilization.     

Rice Straw-Derived Biochar Properties and Functions as Cu(Ⅱ) and Cyromazine Sorbents as Influenced by Pyrolysis Temperature

In this study, biochars from rice straw(Oryza sativa L.) were prepared at 200–600?C by oxygen-limited pyrolysis to investigate the changes in properties of rice straw biochars produced at different temperatures, and to examine the adsorption capacities of the biochars for a heavy metal, copper(Ⅱ)(Cu(Ⅱ)), and an organic insecticide of cyromazine, as well as to further reveal the adsorption mechanisms.The results obtained with batch experiments showed that the amount of Cu(Ⅱ) adsorbed varied with the pyrolysis temperatures of rice straw biochar. The biochar produced at 400?C had the largest adsorption capacity for Cu(Ⅱ)(0.37 mol kg-1) among the biochars,with the non-electrostatic adsorption as the main adsorption mechanism. The highest adsorption capacity for cyromazine(156.42 g kg-1) was found in the rice straw biochar produced at 600?C, and cyromazine adsorption was exclusively predominated by surface adsorption. An obvious competitive adsorption was found between 5 mmol L-1Cu(II) and 2 g L-1cyromazine when they were in the binary solute system. Biochar may be used to remediate heavy metal- and organic insecticide-contaminated water, while the pyrolysis temperature of feedstocks for producing biochar should be considered for the restoration of multi-contamination.     

2013年鲁西南地区一次暴雨天气过程分析

利用常规天气图资料、观测资料和NCEP 1°×1°再分析资料对2013年5月25~27日鲁西南暴雨天气过程进行分析,结果表明,强降水发生在高空急流轴右后方低空急流轴的左前方以及江淮气旋顶端;充沛的水汽条件、相对湿度从地面到300 h Pa均达到饱和,低层辐合高层辐散导致强烈的上升运动触发了强降水;高低空急流的耦合和地面气旋配合较好;大气散度、涡度和垂直速度中心与暴雨落区有较好的对应关系;此次暴雨主要是由层状混合性云系造成的。     

饲用大豆粕水分快速测定方法的研究

[目的]快速、准确地测定饲用大豆粕的含水量,满足指导生产的要求.[方法]在饲用大豆粕的4个水分波动区间,通过比较饲用大豆粕水分在130℃烘箱中干燥不同时间与国标GB/T 6435-2014饲料中水分的测定方法干燥的效果差异来选择合适的干燥时间,优化实际生产中的水分测定方法.[结果]试验表明,饲用大豆粕在130℃烘箱中干燥20 min测定的水分含量与GB/T 6435-2014所用方法结果相近,这说明在130℃烘箱中干燥20 min的快速水分测定对在线生产有一定的指导意义.[结论]在生产过程中可以使用在130℃烘箱中干燥20 min的方法代替国标法进行饲用大豆粕水分的检测,在确保数据准确性的条件下,此法能够极大地缩短检测时间,及时、有效地为车间生产提供数据指导.     

“5.22”贵州省西南部大暴雨成因分析

利用Micaps3.1常规资料、两要素自动站降水资料、卫星资料、NCEP再分析资料,对2012年5月21 ～ 22日贵州省西南部出现大暴雨天气过程进行分析.结果表明,高空槽、中低层的低涡切变以及地面冷锋是造成此次大暴雨过程的大尺度影响系统;卫星云图资料分析表明,此次大暴雨过程中有Mesoscale Convective Complex(以下简称MCC)生成、发展,强降水落区随MCC的移动而移动,由此可见,中尺度系统是此次大暴雨过程的主要影响系统;近地面至650 hPa的充沛水汽条件以及强烈的上升运动是造成此次大暴雨的直接因素,θse的演变很好地反演了此次暴雨过程;最强降水时段出现在MCC发展强盛期,水汽通量散度、垂直螺旋度的大值中心位置和强弱变化与强降水的位置和强度变化均有比较好的对应关系.     

热脱附-气质联机法测试挥发性有机物的解析条件研究

采用热脱附-气质联机法测试空气中挥发性有机物,对热脱附仪工作时的解析温度、解析时间、载气流速及冷阱温度等条件进行分析比较,得出最优化的热解析条件,以提高分析准确度,降低检出限。     

樟树黄化病与树皮电阻值、含水量关系的研究

对樟树黄化病发病程度与树皮电阻值、枝条含水量之间的关系进行了研究。结果表明:黄化病发生程度与树皮电阻值呈正相关;与树皮含水率呈负相关;树皮电阻值与含水量呈负相关。该研究揭示了樟树黄化病的发生发展机理,可用树皮电阻值取代树皮含水量,测定树木生长势或病情,从而简化测定程序。     

称重法测木材含水率的干燥窑用单片机控制

本文给出了根据干燥基准和由称重法测得的样板含水率以控制木材干燥窑内干、湿球温度变化的单片机控制方案，叙述了其工作原理、工作过程以及防干扰措施。