A NOTE ON THE REDUCED EFFICIENCY OF THE INDUSTRIAL CYCLONE

In this paper a theoretical investigation into the basis of the reduced efficiency of a conical cyclone is performed. By considering the flow in a region where viscosity is unimportant an analytical solution to the problem is obtained. From this model the performance of the cyclone is evaluated and this can be expressed in terms of three operating and design parameters. One of these parameters is the split ratio, that is the proportion of the volume of fluid entering the cyclone which goes to the underflow. It is demonstrated mathematically that the empirical formula for the reduced efficiency at present in common use is a very good absolute measure of the separating ability of a cyclone.     

Practical Design Model for Calculating Bubble Diffuser Contactor Ozone Transfer Efficiency

Ozone transfer to water or wastewater is necessary before desirable, effective ozone reactions occur. Several factors affect ozone transfer efficiency, including water quality characteristics, contactor configuration, and applied ozone characteristics. The design model presented in this paper addresses all factors affecting ozone transfer. The model was used to compare measured transfer efficiency with predicted transfer efficiency at four full-scale wastewater ozone disinfection facilities. A relatively good prediction was obtained at each plant.

The paper presents an example calculation of ozone transfer efficiency. Also, the effect of changes to some of the factors affecting transfer efficiency is presented, such as changes in diffuser depth, plant elevation, ozone concentration, water quality (i.e., ozone demand), pH, detention time, temperature, and acombination of factors. The design model may be used to evaluate the effect of changes in plant design on transfer efficiency, but cannot provide an absolute value for transfer efficiency until difficult-to-measure parameters, such as bubble diameter, are known.     

数学题库及自动组卷系统的设计与实现

本文介绍的数学题库及自动组卷系统使用了C＋＋/VC课程的基本设计方法,是基于windows平台下的数据库系统,界面有几个模块组成,分别为登录模块,维护模块,浏览模块和出卷模块等模块界面。自动出卷模块和组卷模块为出卷模块包含功能,修改、删除、添加等功能则集合于维护模块。本系统主要运用的后台数据库为Access数据库,选用Visual Basic为开发工具。     

Crystal transformation from the α- to the β-form upon tensile drawing of poly(l-lactic acid)

A film of poly(l-lactic acid) (PLLA) consisting of highly oriented α crystals was uniaxially drawn by tensile force. The effects of the draw ratio (DR), draw temperature (T_d), and draw stress on the crystal/crystal transformation from the α- to the β-form crystals were studied. At the initial stage of drawing, the highly oriented α crystals of the starting film transformed into a broader orientation distribution, and significant crystal disorder was introduced. Upon further drawing, the α crystals steadily transformed into β crystals with increasing the DR. For the drawing at a constant T_d, the crystal transformation proceeded more efficiently at a higher draw rate and, hence, at a higher draw stress. Furthermore, for the drawing at a constant draw rate, the transformation proceeded with DR most efficiently for the tensile draw at a T_d around 140 °C, although the draw stress increased with decreasing the T_d. The present result combined with the previous finding in the drawing of PLLA by solid-state extrusion [Macromolecules 36 (2003) 3601] suggests that there is a T_d of around 140 °C at which the crystal transformation proceeds most efficiently with DR, suggesting that there are two factors that have opposite effects on the efficiency of the crystal transformation with increasing the T_d. However, as a result of the combined effects of the T_d and DR on the crystal transformation and the ductility increase with the T_d, an oriented film consisting predominantly of β crystals was obtained by tensile drawing at a T_d in the range of 140-170 °C to the highest DR achieved at each T_d.     

对新形势下加强思想政治建设的思考

加强思想政治建设是通过宣传、教育、培训等方式,帮助干部职工确立正确的世界观、人生观,提高他们认识世界和改造世界的能力,自觉地完成单位工作目标任务。在明确思想政治建设的基本要求的基础上,提出了加强思想政治建设的三项工作内容,即加强理论学习、加大制度创新、培养理想信念。同时,针对最常用的个别教育疏导和集体组织上大课两种形式,提出了注重以情感人、善于寓教于乐、讲求因人施教和注重激励引导四种工作方法。     

板式空冷器导流板式液体分布器结构与流动规律研究

对导流板式液体分布装置的结构提出设计方法并进行了数学描述,推导得出了结构压降公式。采用CFX对该结构进行流场模拟,流场显示入口流体的分布。提出的结构设计方法和压降公式对于板式空冷器液体分布器的设计具有一定的理论指导意义。     

我国企业应收账款风险的成因分析及其防范措施

文章分析了应收账款风险产生的原因,指出产生应收账款风险的原因有＂销售部门与财务部门有效沟通及协调不足、企业内部激励机制单一,企业法律保护意识薄弱、催收方法不合理、减少存货、盲目追求片面的竞争,缺乏风险防范意识、信用管理制度的缺失、财务会计制度的某些条款不尽合理、企业的经营目的不明确＂。针对以上应收账款形成风险的原因,本文提出了＂加强销售与财务的共同管理,结‘对’管理、建立完善的信用管理体系、建立赊销审批制度、采取合理的催款程序及方法、掌握客户债务的动态变化、规避不合理的财务制度、从企业管理的角度看应收账款＂等防范措施。     

煤炭复合型助燃固硫剂的开发与研究

通过对不同粒径煤样的全硫量及黄铁矿硫量的测试分析,以及在燃烧过程中生成酸性气体,从而选用复合型碱性固硫剂来进行固硫试验。通过对这几种试验方案的优选比较分析,确定按煤90%∶CaO 9%∶NaCl 1%的配方脱硫率高且成本低廉,可适合工业化生产使用。同时,用高精度微机全自动量热仪做上述配方的煤燃烧热效率实验,结果表明,煤热效率有明显的提高。这说明复合型碱性添加剂不但可促进煤炭的燃烧,同时在燃烧的过程中取到固硫的作用。     

浅谈如何培养一流的知识型员工队伍

在知识经济时代,培养知识型员工,是一个组织(团队)耐以持续发展的潜在资源方略。达到整合团队资源,提升整体素质,实现组织成员的共同愿景,企业应着重于从建立内部培训考核机制和学习激励机制,以及设计个人职业生涯,提升团队整体素质等方面入手。     

建筑物公共区域能量有效性确定

公共建筑中公共区域人流量变化很大,能量的需求也应随着人流量的变化而变化。但传统模式下能量输出却很少考虑人流量的变化,这就造成了部分能量无效。如何评价能量有效性,以减少能量浪费是建筑节能需要研究的问题。提出了能量利用效率概念,用于判断人对能量的利用程度,给出了能量利用效率的计算方法。在某医院公共候诊区进行了工程实验,对比实验前后的能耗状况发现,能量利用效率能够评估能量有效性的状况,以提高能量利用效率为控制目标,可以较大幅度提高建筑物公共区域能效。