Pressure venting of dust explosions in large vessels

The validity of the dust explosion venting nomograph D in NFPA 68 was examined in tests with vessels having volumes from 2.4 to 250 cubic meters and with dusts of classes St 1 and St 2.     

Hydrodynamic aspects of venting for vessels containing viscous fluids

Nine depressurization experiments for vessels containing water, freon-114 and high viscosity fluids have been analyzed. These experiments were carried out at different plants and provide information about the dependence of the depressurization process on the size of the vessel, the type of vent installed, and the initial conditions. The differences of venting into the atmosphere or venting into a catch tank have been also examined. The accuracy of the two-phase flow model used for the analysis of these experiments has been demonstrated by comparisons with steady state data referring to co-current liquid/vapor flow as well as to batch type of flows, where the liquid phase is stagnant.     

Dust explosion venting for dusts pneumatically conveyed into vessels

The size of venting areas of containers in dust explosions has hitherto been calculated by use of nomograms developed from tests in which explosible dust-air mixtures were produced by rapid discharge of combustible dust from storage containers. Such tests did not truly reflect the conditions prevailing when containers are charged with product in industrial practice. There was, therefore, a need to perform dust explosion tests with vented containers and pneumatic product filling. The results of such tests show that there is a considerable reduction in the venting area in comparison with that predicted from results obtained with earlier test procedures.     

Emergency relief vent sizing for fire emergencies involving liquid-filled atmospheric storage vessels

For large atmospheric vessels the potential occurrence of sufficient liquid swell resulting in two-phase flow is of special importance. Based upon an extension of analytical work it would appear justifiable to ignore two-phase flow effects for non-foamy systems.     

Disengagement predictions via drift flux correlation vertical,horizontal and spherical vessels

The behavior of an open system is modeled. Thus, for special cases, the void fraction is predicted as a function of location and time. The open system may be an open vessel or a vessel with an open relief device. A single governing equation is derived based on combining the material and energy balances with the churn-turbulent drift flux relationship and assuming no radial gradients. This partial differential equation is not solved. It is, however, bounded by homogeneous and all vapor venting. These special cases are solved. In homogeneous venting the key variable is time. In all vapor venting under pseudo-steady-state conditions the key variable is location. The solution of the partial differential equation is also discussed. Under pseudo-steady-state and churn-turbulent conditions, the open system is modeled. The minimum void fractions (corresponding to a maximum liquid inventory) with all vapor venting, for vertical, horizontal, and spherical vessels are predicted and compared. Analytical expressions for the local and average void fractions in a vertical vessel and non-unity distribution parameters are presented. Void fraction profiles are compared for three cases: 1. vertical cylinders with distribution parameters (Co values) of unity and 1.5, 2. horizontal and vertical cylinders with varying L/D ratios, and 3. spheres with inscribed vertical cylinders having constant gas production to bubble rise ratio (Ψ′ value). The vertical cylinder average void fraction for non-unity distribution parameters can now be calculated analytically. The horizontal cylinder average void fraction predicted by turning it upright results in an over prediction of at most 4%. The sphere average void fraction predicted via an inscribed vertical cylinder, with the same Ψ′ value, is consistenly high by at most 8%.     

Portfolio assessment in practice in engineering

Summary A portfolio assessment scheme, introduced for one course in 1990 in the School of Engineering, Sheffield Hallam University is proving to be both a stimulus and support for change. The scheme is described and its impact discussed in terms of staff development, the student experience and curriculum development.     

Nutrition in socioeconomic planning in LDCs

Nutrition should be seen as an integral part of the national planning effort. The author examines longterm determinants of food consumption in developing countries and shows that progress in improving nutrition is closely related to raising productivity and efficiency in the national economy. Optimum programmes in nutrition should be part of the design of appropriate social and economic development. This should be done at national and regional levels, with particular emphasis on the regional level.     

十年巨变看舞阳

1997年5月，笔者受当时的冶金部部长刘淇的委托，带领扭亏调查组到舞阳钢铁公司（以下简称舞阳），参加企业扭亏工作。当时，舞阳已经连续4年严重亏损，虽然1995年6月，冶金部调整了舞阳的领导班子，生产经营形势有了一定好转，但并没能扭转亏损局面。1996年，全国工业企业超亿元的亏损大户共14个，冶金系统占了6个，舞阳就是其中之一。在调查工作的后期，刘淇部长也来到舞阳，听取了调查组的汇报，对舞阳下一步的工作提出了明确要求，并且宣布了部党组的决定，调邯钢总经理助理顾强圻为舞阳钢铁公司的副总经理，协助林承模总经理负责全面工作。同年9月，舞阳实行改制，并入邯钢集团，顾强圻出任舞阳的总经理。目前，顾强圻担任舞阳代理董事长、党委书记。     

我国新型增塑剂亟待开发

10月25日，国家质检总局发出公告：今后将禁止含有DEHA等不符合强制性国家标准规定的物质或氯乙烯单体含量超标的食品保鲜膜进口、出口。这是继今年5月、8月欧盟称中国出口的塑料玩具、套装自行车修理工具、管装橡胶溶液分别含有领苯二甲酸盐酯、苯等增塑剂超标，并据此在欧盟范围内对这些产品发出消费警告后，我国在国内范围对增塑剂产品的一次清理整顿。     

21世纪的中国制造

本文分析了制造业在21世纪世界经济发展中的战略地位和制造业内部结构升级的一般规律；按照“产业竞争优势”理论的原则，分析了20世纪末中国制造业的发展现状，并根据现有基础和市场空间，提出了21世纪中国制造业有预期成长优势的十大产业；从全球经济一体化的高度，提出了21世纪振兴中国制造业的四大发展战略。     

4月欧洲数例玩具召回

西班牙召回中国产塑料玩具武器。玩具表面的小部件松动脱落,可完全放人小部件筒中,小孩吞食会造成气管梗塞的危险。该产品不符合欧盟玩具法规和相关EN71标准。产品扣关。     

Investment opportunities in food production in LDCs

The potential food deficit in many developing countries creates opportunities for foreign commercial investment in food production. The factors influencing the profitability of such investment — agricultural, economic, social, political and investment factors — are examined in this article. Dr Schmid has used these five factors to identify a number of countries where the potential for profitable investment is high. He illustrates the range of good investment opportunities by describing the potential of eight countries — Argentina, Brazil, Columbia, Pakistan, Thailand, Kenya, the Malagasy Republic and the Sudan.     

Slow market growth in China in 2011

In 2011,under the supporting role of the relatively stable domestic macroeconomic environment,the growing income and other factors,the overall domestic market of China’s textile industry still maintained a