Mathematical modelling of drying based on a surface evaporation source term for coupled energy and mass transfer

A mathematical model is developed by introducing a source term and using the coupled mass and energy balances based on the Luikov's system of equations. The source term is due to the surface evaporation of many particles in a solid bed. A numerical scheme based on explicit finite difference method is applied. The prediction of bulk temperature profile and moisture content from the model shows, qualitatively, the same trend as the experimental results found in literature. Additionally, parametric studies are performed to investigate the effect of different parameters such as the porosity, the heat and mass transfer coefficients and the velocity on the overall energy efficiency of the drying process. The present model provides better approximation to an actual drying process, especially in the initial and final periods of drying. Copyright © 2007 John Wiley & Sons, Ltd.     

含氮、氧改性菜籽油润滑添加剂对钢-钢摩擦副和钢-铝摩擦副摩擦学性能的影响

对菜籽油进行化学改性制备了一类氮氧型改性菜籽油添加剂（NOR），并利用红外光谱对其主要官能团进行鉴定。分别通过四球和SRV摩擦磨损试验机考察了以菜籽油为基础油，以NOR为添加剂时对钢-钢摩擦副和钢-铝摩擦副抗磨减摩性能的影响，用扫描电子显微镜观察分析钢球磨斑表面的形貌，同时通过对铝合金磨痕进行X射线光电子能谱分析，探讨了氮氧型改性菜籽油润滑添加剂的抗磨减摩机理。结果表明：以氮氧型改性菜籽油为添加剂，以菜籽油为基础油时，钢-钢摩擦副和钢-铝摩擦副均表现出良好的抗磨减摩作用，其润滑作用机理是由于长链菜籽油分子的载体作用、氮的高反应活性以及二者的协同作用在金属摩擦表面形成了含氮、氧及碳等元素的表面保护膜。     

SBT测井技术在塔河油田低密度固井质量评价中的应用

介绍了塔河油田采用低密度水泥固井的地质背景,指出了低密度水泥固井质量评价的难点.阐述了SBT定量评价低密度水泥固井质量的理论基础和方法原理.最后通过现场SBT测井资料的处理效果表明,该测井方法解释结论真实可靠,突破了常规声波变密度测井的局限性,具有良好的应用效果.     

SBS改性乳化沥青生产新技术

简述改性乳化沥青的生产方法并介绍了一种生产SBS改性乳化沥青的新技术。     

复合菌发酵乳生产及其稳定剂的选择

使用罗地亚MY900复合乳酸菌剂和CMC、黄原胶、变性淀粉、复合稳定剂,对搅拌型酸奶进行应用试验.结果表明当MY900菌剂的接种量为40U/1000L、发酵温度为43℃、发酵时间为5.0～6.0h, 搅拌破乳,制得的搅拌型酸奶口感优良,同时表明使用变性淀粉或复合稳定剂在酸奶生产中是合适的增稠剂.     

活性阴极改性隔膜电槽的使用

采用活性阴极改性隔膜技术对普通隔膜电槽进行改制，降低了槽电压、节电效果显著。     

2002年我国工程塑料应用进展

根据2002年国内公开发表的文献，综述了我国工程塑料及改性塑料在车辆、机械设备、电子电气及通讯、建材、家电及家具、薄膜、兵器等领域的应用情况及研究进展，并介绍了以上领域内塑料新产品的开发、性能评价和使用效果。指出2002年我国塑料新产品的开发应用重点是机械设备、电子电气、建材等领域，汽车、家电、通讯领域较上一年有所减少。     

水泥搅拌桩室内配合比实验研究

本文通过水泥土室内配合比试验,研究出水泥掺量、龄期、外加剂与水灰比对水泥土试件无侧限 抗压强度的影响。     

Physico-chemical properties of flour and starch from jackfruit seeds (Artocarpus heterophyllus Lam.) compared with modified starches

Jackfruit (Artocarpus heterophyllus Lam.) is one of the most popular tropical fruits grown in Asia. The objective of this study was to compare physico‐chemical properties of native flour and starch from jackfruit seeds (A. heterophyllus) to commercially modified starches (Novation 2300 and Purity 4). The colour of jackfruit seed starch was lighter than the Novation 2300 starch but darker than the Purity 4 starch. The jackfruit seed starch had a narrower gelatinization temperature range than Purity 4 and required less gelatinization energy compared with modified starches. The peak viscosity of jackfruit seed starch was lower than commercially modified starches. Likewise, setback viscosity, swelling power and solubility of jackfruit seed starch showed similar trends. Results from this study suggest that native starch from jackfruit seed could be used as an alternative for modified starches in a system needing starch with a high thermal and/or mechanical shear stability.     

修正等时试井资料分析新方法

对于单井控制储量比较低的低渗透致密储集层气井，传统修正等时试井分析方法的不足是：二项式系数偏小甚至为负，稳定点的确定没有完全按定义进行。根据气井早期不稳定渗流理论和渗流叠加原理，对修正等时试井的全过程进行理论分析，推导出确定不稳定及稳定二项式产能方程的校正公式。通过模拟井的检验和对苏里格气田苏6井实际资料的分析，证实对于传统方法不能处理的资料，校正方法具有很好的处理能力，并且计算结果精度更高。图4表2参7