Performance of floating cum tilted-wick type solar still with the effect of water flowing over the glass cover

A simple transient performance of floating cum tilted-wick type solar still has been presented by incorporating the effects of water flowing over a glass cover, heat capacity of tilted-wick water surface and floating-wick water surface. Explicit expressions for flowing water, glass, tilted-wick water surface and floating-wick water surface temperature and efficiency of the system have been derived. Numerical calculations have been carried out for a typical day in the month of March 2004. The relative standard deviations between the numerical and experimental results of different temperature components of the proposed still have been found. The results indicate that the relative standard deviations between theoretical and experimental results are less than 8% (glass cover), 2% (tiltedwick water surface), 1% (floating-wick water surface) and 2% (flowing water at the lower end of the glass cover) an average for the working hours of the day. Moreover, based on the numerical results, the following conclusions have been drawn: (i) glass cover temperature decreases significantly; (ii) the effect of water flowing over the glass cover has a fascinating effect on the production of distillate output during peak sunny hours; (iii) water flow rate of 1.5 m/s is optimum, and beyond it the efficiency decreases. Experimental investigations have been performed at Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore, India.     

GYM系列亿丰磨在非金属矿物超微粉碎中的应用

干法生产超细粉是我国非金属粉体的重要加工工艺之一，传统的粉磨设备难以达到大量生产d97=2—10μm超细粉的要求，且生产效率低。阐述了采用多磨轮、多磨道原理设计的GYM-83型亿丰磨在生产粒径为11μ的碳酸钙干粉时，其累积分布达98％，粒径为2μm的占总质量44．96％，产量达到了1250kg／h，且基建投资少，性价比好。     

SIMULATION AND ESTIMATION OF LONG MEMORY CONTINUOUS TIME MODELS

Abstract. Some general properties of long memory continuous time processes are recalled or proved. Methods of simulation are studied. A comparison with the usual discrete time autoregressive fractionally integrated moving-average filter is made and illustrations are provided. Then, two methods of estimation of the parameters of such a model from a discrete sample are studied, both theoretically and empirically, with Monte Carlo experiments.     

四种杀菌剂对枸杞黑果病的防治效果

枸杞黑果病是枸杞产区的主要病害．发病后造成黑花、黑蕾和黑果，使枸杞产量降低，品质变劣。为探明四种杀菌剂对枸杞黑果病的防治效果及最佳剂量，2003年对下述四种杀菌剂进行了田间药效对比试验，调查防效结果如下：20％三苯基醋酸锡WP450～281g／hm^2(以有效成分计，下同)，20％氟硅唑EC21．08g／hm^21．5％噻霉酮EW16、88～21．08g／hm^2、40％氟硅唑EC450g／hm^2和70％甲基托布津WP787．5g/hm^2对枸杞黑果病防效均在88．25％以上。经LSD检验各处理间防效无显著差异。     

Φ10007/00有压三产品重介旋流器结构参数优选与分选效果

辛置选煤厂针对原煤煤质变化后的特点 ,采用有压给料三产品重介旋流器为核心的高效选煤工艺系统分选 5 0～ 0mm原煤 ;对旋流器一段及二段中心管的直径和插入深度、二段底流口的直径等进行了优化调整 ,同时调整了介质泵的工作频率及悬浮液密度等参数 ,取得了分选效率高、产品质量稳定等显著效果     

Anaerobic fermentation of xylose by pichia stipitis: The effect of forced cycling of ph

Xylose fermentation by Pichia stipitis was examined using a two-stage batch process. The cells were first grown aerobically on D-xylose (5 g/L), whereafter additional xylose (10 g/L) was added and fermented during anaerobic conditions (T=30°C). The optimum pH value for a fermentation with constant pH was found to be 4.5 (maximum specific ethanol production rate 0.21 g/(g h). Forced square wave cycling of the pH between 4 and 5, and 3.5 and 5.5 (cycle time 30 min) during the fermentation stage resulted in a fermentation rate lower than the maximum rate, but with unchanged ethanol yields.     

On the catalytic C-H activation of some silicon dioxide overlayers on thin metal film systems — An observation on the isokinetic effect

Kinetic data on the exchange reaction betwee hexane and deuterium have recently been reported by Maier and coworkers [1]. The reaction was catalysed by a series of platinum or rhodium systems, some of which had the property that the upper surface was shielded by a silica overlayer. The data are reinterpreted to indicate an isokinetic temperature of 580 K. This observation indicates that all the catalysts behave in a similar manner, which means that the exchange reaction does not require a free metal surface.     

Adhesion Effects of Intermediate Layers on the Densification of Ceramic Powders

In the ceramic technology the first step to produce sintered bodies is the manufacturing of powders which then are densified. The adhesion mechanisms between the single particles and the agglomerates produced from them determine the densification process. Starting from theoretical considerations adhesion mechanisms, such as solid bridge formation, adhesive bonding and glide-promoting effects, are discussed in principle. Subsequently, the effects of surface-active substances on the densification behaviour of clay-ceramics and oxide-ceramic bodies are discussed. Further, the evaluation of the action of additives to the powder mixtures on the microstructure of the compacts, such as porsity and texture, leads to a compaction equation which describes the transition from the powder pile to a densified green body.     

降低循环流化床锅炉飞灰含碳量的因素分析

循环流化床锅炉的飞灰含碳量是锅炉燃烧工况好坏的直接反映 ,其对锅炉的热效率的影响是很大的 ,它还直接影响着粉煤灰的综合开发和利用 .在对云天化循环流化床锅炉的生产实验研究中 ,分析了影响循环流化床锅炉飞灰含碳量的各种因素 (床温、煤质煤粒、一次风、二次风、床压和旋风分离器效率等 ) ,通过实验研究找到了降低循环流化床锅炉飞灰含碳量的具体而又行之有效的操作方法 ,以指导实际生产 .     

削弱或抑制抗氧剂、光稳定剂作用的有关因素

介绍了削弱或抑制抗氧剂、光稳定剂作用的常见因素及实例，分析了防老化塑料制品发生提前老化现象的可能性和原因。