混凝+UF作为RO进水前处理的适用性研究

本文采用混凝＋UF作为RO进水的前处理,以颖河河水为原水进行了中试实验研究,考察了混凝剂投加量、曝气量、不同抽滤时间对超滤系统的影响.结果表明：混凝剂（PAC）投加量为14mg/L,曝气量为7.08L/s时,超滤对原水浊度的平均去除率为99.2%,出水SDI平均值为1.26,完全达到反渗透进水的水质要求,且水质稳定,混凝和超滤膜联用作为RO前处理是完全适用的.     

CASS反应池结合ClO2消毒工艺在处理某医院废水的应用

采用CASS池结合ClO2消毒工艺处理某医院污水,结果表明,出水COD、BOD5、氨氮、总磷的质量浓度和去除率分别为23～65 mg· L-1、77.38％～90.81％; 11～65 mg·L-1、66.36％～90.91％; 0.12～2.87 mg·L-1、73.57％～98.47％;1.0～1.4 mg· L-1、58.32％～65.01％;总大肠杆菌群低于1 000· L-1,去除率为97.08％～99.83％;接触消毒池出水余氯为3.1～3.5 mg· L-1.各项指标基本达到了污水综合排放标准(GB 8978-1996)的二级排放标准.表明CASS池结合ClO2消毒工艺能有效的处理医院废水.     

AN EXPERIMENTAL STUDY OF SOLIDIFICATION OF BINARY MIXTURES WITH DOUBLE-DIFFUSIVE CONVECTION IN THE LIQUID

An experimental study is reported of solidification of ammonium chloride-water solutions inside a rectangular enclosure. The phase-change and convection processes are studied through shadowgraph and flow visualization as well as temperature and concentration measurements. A number of different initial and boundary conditions are utilized in the experiments in order to obtain a representative data base of the system behavior. It is found that the solidification process induces a variety of double-diffusive convection phenomena in the liquid, including layers, plumes, and stable stratifications. The convection processes influence considerably the local solidification rates and can cause remelting in parts of the system. It is emphasized that many of the physical phenomena identified through the present experiments are expected to be of considerable importance in actual casting processes involving metallic alloys. Consequently, careful consideration must be given to these phenomena when developing more realistic models of solidification processes. The present experiments should serve as a data base for both qualitative and quantitative validation of such models.     

高分子量聚对苯二甲酰对苯二胺硫酸溶液热稳定性的研究

高分子量PPTA树脂在浓硫酸中的热稳定性与温度、溶液浓度以及溶解时的搅拌速度有关。随着温度升高,其热稳定性降低;当溶液浓度低于16%(W/W)时,浓度越低其热稳定性越差,当溶液浓度达到16%以上时,浓度对其热稳定性没有明显的影响;溶解时搅拌速度增大,其热稳定性变差;不同分子量的PPTA树脂在硫酸中的热稳定性基本相同。     

填充床电渗析器制备纯水的研究

本文介绍了离子交换树脂在填充床电渗析器中的脱盐及电再生机理，实验研究了一价离子及二价离子在设备内的操作参数。一价离子与二价离子相比，树脂使用周期长，操作范围宽，对于一价离子，树脂可在低电压下（〈２５Ｖ）再生，在较高电压下（〉２５Ｖ），树脂内的一价离子及二价离子均可再生。操作电流应略大于极限电流，以保护产水质量。     

副产物含量对栲胶脱硫液性质的影响

在栲胶脱硫生产过程中除了主反应外,同时还伴随Na2S2O3,Na2SO4,NaSCN及NaHCO3等盐类生成的副反应.这些副产物的生成会影响栲胶脱硫液的性质,并最终影响整个脱硫循环工艺的稳定.为了避免这些影响,从表面张力、黏度和密度三个方面分析了Na2S2O3,Na2SO4,NaSCN和NaHCO3四种栲胶脱硫工艺的副产物对栲胶脱硫溶液的影响.结果表明,副产物的积累可以引起脱硫溶液表面张力的下降以及溶液黏度和密度的增加,从而引起脱硫工艺中操作条件的改变,最终影响整个系统的脱硫效率.     

陶瓷色料用于耐热煲色釉装饰的应用试验研究

通过将各种颜色的陶瓷色料加入到耐热煲瓷釉中,在1300℃氧化气氛下烧成,考察研究各种色料的发色情况。结果表明:含铬的绿色料、钒蓝、海蓝和宝蓝色料、钒黄色料、包裹料等发色较好,釉面光亮平滑;铬锡红色料严重褪色;其余色料则出现针孔、气泡、起泡等釉面缺陷。     

AN ANALYTICAL STUDY OF THE TRANSIENT MOTION OF A DENSE RIGID SPHERE IN AN INCOMPRESSIBLE NEWTONIAN FLUID

A theoretical study of the transient sphere motion (under the influence of gravity) through an incompressible Newtonian fluid subject to an Oseen-type drag relationship has been carried out. Exact closed form expressions for the instantaneous position, velocity and acceleration of the sphere are presented. An analytical expression developed herein also enables the delineation of the “best” sphere-fluid combination for the experimental observations of transient effects and these provide useful guidelines for designing laboratory experiments. However, this study is restricted to dense spheres falling in light liquids when the additional effects arising from the added mass and the Basset forces are negligible. Also, the boundary effects are altogether neglected.     

平板膜式氧合器中氧传质系数近似计算的积分法

应用Graetz-Leveque问题的前进边界理论的修正近似解,进一步分析了半透膜阻力对氧传质速率的影响,获得了与Graetz-Leveque问题精确解非常接近的(相对偏差在6.58%以下)用于计算平板膜式氧合器中氧传质系数的简单分析表达式.并提出了基于氧传质速率计算的该类氧合器通道长度设计的临界判据.     

改性石英砂强化火电厂中水回用微污染物处理效果研究

通过对石英砂滤料的改性研究改变原滤料表面物理化学性质,提高滤料吸附能力和截污能力,强化对中水中有机物的去除效率。分别试验了对石英砂进行铝盐和铁盐方法的改性,过对比了静态吸附试验和动态过滤试验改性石英砂和未改性石英砂对微污染水中有机物和浊度的去除效果。结果表明,改性砂对COD和浊度的吸附效果较之未改性前均有明显提高,COD去除率由5%提高到20%～30%,浊度的去除率由37%提高到55%～65%,动态试验与静态试验结果一致,去除率也均有提高;不同金属氧化物的改性砂性能不同。     

EXACT ANALYTICAL SOLUTION OF A LUMPED MODEL OF THE TRANSIENT CONVECTIVE-RADIATIVE COOLING OF A HOT SPHERICAL BODY IN AN ENVIRONMENT

In this study the exact analytical solution of the lumped parameter model of a nonlinear heat transfer process representing the transient convective-radiative cooling of a spherical body has been obtained. The process is governed by a nonlinear ordinary differential equation, and the exact analytical solution has been found in the implicit form of an elementary transcendental function. The obtained exact analytical solution not only yields accurate results but also successfully simulates a recent experimental study of cooling of metallic ball bearings by the combined mechanism of convection and radiation. In addition, the exact explicit solution for a simplified case of the above problem, recently tackled by several researchers in various approximate ways, has also been found. These exact solutions are quite appealing since they are accurate and superior to the available approximate solutions, provide better insight of the physical process, and can also serve as yardsticks for future testing of the approximate solutions.     

细鳞片石墨化学氧化法制备可膨胀石墨技术问题探讨

采用分步氧化法制备了80目细鳞片可膨胀石墨。通过L9（3^4）正交试验确定了最佳工艺条件。在液固比-5：1，C：KMnO4=1：0．12，Ⅰ H2SO4：Ⅱ H2SO4=4：1，H2SO4：H2O2=12：1（均为质量比g／g）条件下获得膨胀容积为290mL／g。对制备过程中液固比、硫酸浓度、双氧水的加入方式、可膨胀石墨烘手温度、原料粒度等因素对膨胀容积的影响以及可膨胀石墨的稳定性的改善方法进行了探讨。     

乙二醛溶液体系中乙酸络合萃取的动力学研究

采用恒界面池法研究了乙酸在乙二醛溶液中的萃取动力学,实验结果表明：萃取速率由界面化学反应所控制,且表观反应速率方程为：ｒ＝ｋｓＣＨＡｃ１．３６４１,在２５℃时的反应速率常数ｋｓ＝１．８２×１０－２ｍｏｌ／ｃｍ２·ｓ。此外,还研究了温度对反应速率的影响,求取了表观反应的活化能Ｅａ＝２３．２８３３ｋＪ／ｍｏｌ,从而进一步说明了萃取速率控制步骤为界面化学反应所控制。     

组合人工湿地对渗滤液中重金属的去除

选用芦苇 凤眼莲和灯心草 凤眼莲 菹草两种人工湿地植物组合构筑了两种小试人工湿地,取内江市高桥镇垃圾填埋场的垃圾渗滤液进行试验研究.结果表明,这两种人工湿地对渗滤液中的重金属均有良好的去除效率,特别是灯心草 凤眼莲 菹草的组合,对重金属铅、镉、铜、锌的去除效率均在95%以上.表现出良好的发展应用前景.     

AN APPLICATION OF SIMULTANEOUS HEAT AND MASS TRANSFER IN A CYLINDER USING THE FINITE-DIFFERENCE METHOD

A study of simultaneous heat and mass transfer during drying an infinite cylinder shape material (twigs of ilex paraguayenais saint hilaire) was carried out. The finite-difference method was used to solve the drying model and a simultaneous heat and mass balance in each node was made. Models with different assumptions were tested and the external mass transfer coefficient was used as a parameter to fit the model to experimental data. The thickness of the node and the time step were selected considering the system stability.

Drying temperature, twig diameter and air velocity were selected as study variables. The models results were in good agreement with experimental measurements giving mass coefficient values between 1.97 10^-4and 9.55 10^-4 Kg/m² s.     

AN APPLICATION OF SIMULTANEOUS HEAT AND MASS TRANSFER IN A CYLINDER USING THE FINITE-DIFFERENCE METHOD

ABSTRACT

A study of simultaneous heat and mass transfer during drying an infinite cylinder shape material (twigs of ilex paraguayenais saint hilaire) was carried out. The finite-difference method was used to solve the drying model and a simultaneous heat and mass balance in each node was made. Models with different assumptions were tested and the external mass transfer coefficient was used as a parameter to fit the model to experimental data. The thickness of the node and the time step were selected considering the system stability.

Drying temperature, twig diameter and air velocity were selected as study variables. The models results were in good agreement with experimental measurements giving mass coefficient values between 1.97 10^?4and 9.55 10^?4 Kg/m² s.     

AN EXPERIMENTAL STUDY OF METHANE OXIDATIVE COUPLING IN FIXED BED REACTORS WITH A DISTRIBUTED OXYGEN FEED

Methane oxidative coupling has been carried out in a reactor with a distributed oxygen feed. The system consists of a catalytic bed of Li/MgO in a quartz reactor with one inlet for methane and one or more inlets for oxygen. To enable the comparison between the co-fed mode and the distributed feed mode, an especial experimental design was used in order to maintain the same contact time in the co-fed and in the distributed feed modes, and in order to minimize the temperature gradients caused by the exothermic oxidation process. The results clearly show that a distributed oxygen feed may give rise to significant increases in the hydrocarbon selectivity obtained at a given methane conversion,     

AN APPLICATION OF THE FINITE ELEMENT COLLOCATION METHOD IN SOLVING SELECTED PROBLEMS OF SUBMICRON AEROSOL FILTRATION. THE CASE OF THE SLIP FLOW ON A FIBRE

The convective diffusion equation of aerosols in the case of gas stream slip on the fibre cylindrical surface has been solved by means of the finite element collocation method. Half-analytical form of the solution makes it possible to examine directly changes the slip causes in the distribution of solids around the fibre surface. Concentration profiles and deposition efficiency computed by this method differ from the experiment results less than those obtained by the common method of finite differences. Additionally the finite element collocation has proved to converge more rapidly than that of finite differences (at optimal conditions of calculation for both methods).¹⁰     

AN EXPERIMENTAL STUDY ON THE PERFORMANCE OF A SINGLE DISCHARGE WIRE-PLATE ELECTROSTATIC PRECIPITATOR WITH BACK CORONA

The phenomenon of back corona is well known in that it may reduce the collection efficiency of an electrostatic precipitator. In this study, experimental results are presented for the influence of back corona on the performance of a laboratory scale single-discharge-wire ESP system. The effect of back corona under two power controlled methods, constant voltage operation and constant current operation, has been evaluated. The experimental results showed that as back corona occurs, the output current and the power consumption are increased under constant voltage operation. The mass collection efficiency is proportional to the applied voltage. On the other hand, for constant current operation the voltage and the power consumption are decreased under back corona. The mass collection efficiency is independent of the applied current. A lateral mixing model was also applied to assist in the discussion of corona power and particle collection efficiency under normal and stable back corona conditions. Both experimental and theoretical results indicated that the back corona has a large effect on submicron particles. The grade efficiency can be reduced by over 60% for submicron particles. The large reduction of efficiency for submicron particles is due to significant reduction in both particle charge and migration velocity. Since particles in the submicron region are more sensitive to light scattering, the opacity problem may be aggravated under back corona.     

降低双酚A型环氧树脂可水解氯含量方法的探讨

可水解氯含量是环氧树脂一个十分重要的特性指标，它同固化速度、无机氯、杂质离子含量等指标一样表征了环氧树脂的内在质量，它区别于环氧值（或环氧当量）、软化点、粘度等主要作为划分不同分子量环氧树脂规格的指标，因为可水解氯含量的高低直接影响环氧树脂的固化行为和固化产物的性能。因此在提高环氧树脂质量时，降低可水解氯含量的重要性是显而易见的。本文以典型的双酚A环氧树脂（DOEBPA）为例，对它形成的机理，降低可水解氯含量的工业化工艺路线的实验摸索作了初步探讨。