Water circulation induced by mechanical aerators in a rectangular vessel for shrimp aquaculture

A water streamer was designed for the purpose of enhancing cost-efficient circulation between the water surface and bottom of shrimp aquaculture ponds. We took direct measurements of the water current field induced by the designed aerator in a large rectangular reservoir of dimensions (L)50 × (W)19 × (D)1.3 m³ and compared the results with those of a standard Taiwanese paddle-wheel aerator. Vertical circulation between the surface and the bottom induced by the paddle wheel aerator was less than that by the designed aerator. Furthermore, the paddle-wheel aerator consumed more electric power than the designed aerator. The structures of water current induced by the two aerators are elucidated, and the advantages and disadvantages of the aerators are discussed.Auxiliary employment of the designed aerators may contribute to delivery of high DO water throughout the pond, which is more efficient than a paddle wheel aerator.     

聚脲喷枪混合室的设计和FLUENT仿真分析

为提高聚脲喷涂喷枪的混合效果，基于撞击流理论设计了一种新型聚脲喷涂喷枪的混合室。混合室采用两级撞击混合，分别采用两组T型和两组Y型对撞混合形式。利用SolidWorks设计混合室的结构模型后，利用FLUENT软件，采用冷、热水在混合室内撞击混合、对流传热的方法进行仿真模拟，并且计算了流体在混合室内的微观混合时间。结果表明:合理增加撞击流混合室的混合级数和采用多组T型、Y型对撞混合形式可增益混合效果；撞击流混合室的主要混合区是在撞击区；流体在喷枪内停留的总时间约为5.71 ms，满足具有反应迅速这一特性的材料的混合要求；微观混合时间小于1 ms，混合效果优异。      

水肥一体化中水肥混合效果数值模拟研究

为研究水肥一体化技术中的水肥混合特性,以流体力学中的两相流理论为基础,针对水肥混合过程中混合时间、混合区间长度、流速及管径对其混合效果的影响进行相应的数值模拟研究。结果表明,混合时间及混合区间长度越长有利于提高水肥混合效果及最终水肥混合均匀性;水肥流速比较低时管内水肥混合的均匀性较好,且水肥流速越大则其混合效果及均匀性越好;水肥流速较低时输水管及输肥管的管径比对水肥混合均匀性的影响较大,两者管径比越小则混合效果越好,随着流速的提高两者管径比对其混合效果的影响逐渐减弱。     

土壤中缓效钾的批量快速测定

通过对NY/T 889—2004标准中前处理方法的改进,建立了批量、快速、准确测定的土壤中缓效钾的方法。以石墨消解代替油浴消煮测定标准土中的有效钾,以验证改进后方法的可行性。结果表明,改进后的方法一次可以测定36个样品,且3 min内沸腾时间对结果无显著影响。因此,改进后的方法操作简单、条件易控制、准确快速,能实现对土壤中缓效钾的批量、快速测定。     

利用甜高粱秸秆汁产单细胞蛋白的分批补料发酵研究

本文以甜高粱秸秆汁为主要的发酵原料,对热带假丝酵母SG-1在15-L罐上产单细胞蛋白(SCP)的分批补料发酵过程进行研究。首先对分批发酵模式下的菌体代谢过程变化进行研究。研究发现,接种后菌体快速进入繁殖阶段,但是总糖在12 h处于耗竭状态,使得菌体量和SCP产量过早的在18 h就达到峰值。基于此,在15-L罐上建立了热带假丝酵母SG-1产SCP的分批补料发酵模式。结果表明:菌体代谢因基质的补加而得到进一步的延续,放罐时(42 h)其菌体干重和SCP产量分别达19.86 g/L和9.93 g/L,显著高于分批发酵模式的10.45 g/L和4.70 g/L。     

Pathological analysis of batch safety testing of veterinary vaccines using small laboratory animals

Batch safety tests (BSTs) of veterinary vaccines are conducted using small laboratory animals to assure the safety of vaccines according to several criteria, including clinical signs and change in body weight. Although the latter is used as an evaluation index in BSTs, there have been no reports on the internal changes that affect body weight during the test period. Therefore, we analyzed BST via pathological examination of the tested animals. Here, BSTs were performed for 176 batches using mice and 126 batches using of guinea pigs. Most of the gross findings could be classified into four lesion types (nodules, adhesions, ascites, no apparent signs), with only one vaccine inducing lesions that could not be classified into any of these four types. Histopathological examination revealed that the reactions caused by BST were pyogenic and/or granulomatous inflammation. Nodular or adhesive lesions comprised more severe pyogenic granulomatous inflammation than ascites or cases with no apparent gross lesions. These nodular or adhesive lesions were more frequently induced by vaccines that contained an adjuvant than by vaccines that did not contain an adjuvant. The cases with “exceptional” gross findings histologically presented severe necrosis of the hematopoietic system. Additional testing showed that these “exceptional” lesions were induced when a specific type of light liquid paraffin was injected along with other vaccine additives. Our results show that body weight loss and/or lesions during BST were induced by proinflammatory properties of the tested vaccines and that BST is a sensitive method for detecting unexpected effects of vaccine components.     

饲料混合机的混合机理及工作性能的评定

混合是生产配合饲料和混合饲料的关键工序,其目的是将配合后的各种物料在外力作用下相互掺合,使各种饲料能够均匀分布。饲料混合机作为混合工序的主导设备,其工作性能显得尤其重要。为此,介绍了我国典型饲料混合机的混合机理以及混合性能的评价指标体系,讨论了混合均匀度的表示方法和测定方法,分析了饲料混合机的发展前景。     

高校图书馆批量退证系统的设计与实现

针对高校图书馆在毕业生退证高峰期所面临的问题,介绍了惠州学院图书馆批量退证系统的设计目标及思路,并对批量退证系统实现过程中对相关表的解读、数据库的连接方法和功能的实现过程进行了详细的论述。     

不同处理稻草混合青贮料对奶牛生产性能的影响

本试验采用稻草分别与玉米秸杆、象草混合青贮,同时添加纤维素复合酶制剂和乳酸菌制剂,研究稻草的最佳青贮模式和五种不同处理稻草混合青贮料对奶牛生产性能的影响,结果表明稻草与玉米秸杆混合青贮（同时添加纤维素复合酶制剂）料对奶牛产奶量显著高于其它青贮组合（P〈0．05）,但对乳成分无显著影响（P〉0．05）,其它组之间的产奶量和乳成分差异不显著（P〉0．05）。     

潜水泵扩张式喷嘴排液装置的优化设计与试验

针对泄漏液体严重危及潜水泵安全的问题,在原非扩张式喷嘴排液装置的基础上,优化设计了一种具有扩张式喷嘴的在线排液装置.为了比较分别具有扩张式和非扩张式喷嘴的排液装置性能的优劣,设计了这两种形式的喷嘴,并设计了4种不同尺寸喉嘴距及6种不同尺寸混合管直径的排液装置;对各种不同的排液装置在同一试验台上分别进行了试验.试验结果表明,当排液装置的扬程为6 m时,具有扩张式喷嘴的排液装置具有更好的排液性能,其最佳工作压力为0.3 MPa,最佳喉嘴距为1.67倍喷嘴喉部直径之长度,最佳混合管直径为2倍喷嘴喉部直径.与非扩张式喷嘴排液装置相比较,具有最佳尺寸的扩张式喷嘴排液装置可以更好地解决潜水泵液体泄漏问题.