膜分离技术在水处理领域的应用

对2000年底巴黎“饮用水和工业用水制造领域中的膜技术”国际会议进行了简单的回顾，根据会议经历对当今膜分离技术在水处理领域的应用市场进行分析，提出今后液体膜分离技术的研究和发展的重点。最后对我国液体分离膜技术的发展提出一些建议。     

Deflection Calculation of FRP Reinforced Concrete Beams Based on Modifications to the Existing Branson Equation

Fundamental concepts of tension stiffening are used to explain why Branson’s equation for the effective moment of inertia Ie does not predict deflection well for fiber reinforced polymer (FRP) reinforced concrete beams. The tension stiffening component in Branson’s equation is shown to depend on the ratio of gross-to-cracked moment of inertia (Ig/Icr), and gives too much tension stiffening for beams with an Ig/Icr ratio greater than 3. FRP beams typically have an Ig/Icr ratio greater than 5, leading to a much stiffer response and underprediction of computed deflections as observed by others in the past. One common approach to computing deflection of FRP reinforced concrete beams has been to use a modified form of the Branson equation. This paper presents a rational development of appropriate modification factors needed to reduce the tension stiffening component in Branson’s original expression to realistic levels. Computed deflections using this approach give reasonable results with the right modification factor, and compare well with a more general unified approach that incorporates a realistic tension stiffening model. Comparison is made with the existing and past correction factors recommended by ACI 440 for predicting deflection of FRP beams. The method presently used by ACI 440 gives reasonable estimates of deflection for glass and carbon FRP reinforced beams. However, this method underestimates deflection of aramid FRP reinforced beams and is restricted to rectangular sections. A proposal is made for adoption of a simple modification factor that works well for all types of FRP bar and beam cross-sectional shape.     

Bench-Scale Testing of Nanofiltration for Seawater Desalination

A dual-staged nanofiltration process is being evaluated as an alternative to reverse osmosis for seawater desalination. The primary goal of this system is to reduce energy consumption while producing potable water at an acceptable recovery rate. Investigation of this system at the bench-scale level focused on membrane surface characterization, ion rejection (including boron, bromide, and iodide rejection), and flux decline. Results from this study showed that two commercially available nanofiltration membranes can effectively desalinate seawater. Although fouling was apparent—and resulted in approximately 20% flux decline over 3 days—a critical flux was not identifiable. Operation of the system at different cross-flow velocities revealed the significance of hydrodynamic conditions on the polarization modulus, and hence on membrane performance.     

Proposed Design of a CFRP Flange-to-Flange Connection for Precast Prestressed Double Tee Systems

The current methods of connecting the flanges of precast double tee members, and their respective short comings in specific situations, are described. A new carbon fiber-reinforced polymer (CFRP) flange-to-flange connection is proposed to eliminate the problems associated with repair requirements for the current connections. Design expressions for the currently used mechanical anchorage and the proposed CFRP connection are presented. A comparative calculation for the two systems is given.     

特低渗油藏渗流特征及增产技术研究

从特低渗储层渗流机理研究出发，分析了其渗流规律——非达西渗流特征；根据储层中上覆岩石围压变化，通过室内试验表述了其对渗透率伤害。研究提出了改善渗流特征的注水条件、井网优化和压裂对策，可以有效提高这类油藏的开发效果。     

一种复合型数值方法的改进与算法实现

文中对原有的复合方法进行了改进,提出了一种新的复合型数值方法,这种方法解决了原方法求解含源项的问题时存在数值震荡的缺点。为了验证算法的有效性,对计算流体力学中一阶浅水波问题的两个典型的算例进行了数值模拟,在解的光滑性、锐利性等几个方面做了分析,结果表明改进后的方法既消除了数值震荡现象,又能准确地逼近真解,求出锐利的间断,是一种行之有效的数值方法。     

井冈山水厂设计体会

阐述水厂设计中对水厂规模、水源地、净水厂位置及净水工艺的确定过程，根据原水的特点，通过分析对无阀滤池进行改良。     

定向爆破拆除框架式水塔

高 2 7m的水塔建于 193 4年 ,其顶部水罐由 12根钢筋混凝土柱支撑。在倒向侧 7根立柱上形成不同高度的爆破切口 ,背向侧倾倒中心线上的一根立柱上形成小爆破切口 ,其余 4根立柱底部打贯通孔 ,使水塔准确定向倾倒。文中讨论了立柱切口高度的计算 ,爆破参数的确定 ,并介绍了所采用的安全措施。     

电接点压力表补水泵定压系统的应用

阐述了电接点压力表补水泵定压系统的一些应用问题 ,给出了电接点压力表定压点的上、下限计算公式 ,并提出了该系统补给水泵、补给水箱及安全阀的设计选型方法     

油管电热清防蜡技术在强水敏油田的应用

江苏油田的庄 2、韦 2油田属强水敏油田 ,采用热 (水 )洗油井和化学清防蜡效果较差 ,两油田每年因洗井造成地层污染影响的产量损失在 5 0 0 0t以上 ,约占油田产量的 4 5 %。根据集肤效应 ,采用油管电热清蜡技术 ,在含水小于 6 0 %、井斜小于 4 0°的油井上可正常使用 ,一般通电加热 4 0～ 80min后 ,油井井口温度能达到 5 0℃左右 ,最高可达到 6 5℃以上 ,连续加热 5～ 6h即可达到清蜡目的 ,电热清蜡为周期 6 0～ 90d。影响电热清蜡主要指标因素是油井的产液量 ,产液量越小 ,所需要的加热电流和加热电压也越小 ,井口温度达到最高值越低 ,清蜡效果越差。试验的 7口井平均年度投入产出比达到 1∶5 ,经济效益和社会效益十分明显。