自动投矾-微絮两级陶粒直接过滤净水的试验研究

采用自动投矾—微絮两级陶粒直接过滤净水工艺，对增城中新低浊水源水进行试验。主要结论：(1)净水剂投加量增加，出水浊度减少。投加量为3．8-6．0mg／L[以A12(S04)3计]时，出水浊度可降到很低．再增加投加量对浊度影响不大，但会明显缩短制水周期；(2)原水浊度越低，出水浊度越低。当原水浊度在50NTU以内．对出水浊度影响不大；(3)滤速越慢，出水浊度越低。滤速30m/h较适宜低浊水源水；(4)水温对出水浊度影响不大。自动投矾—微絮两级陶粒直接过滤工艺具有方便、实用、占地面积少并可节省净水剂用量等特点，是一种对低浊水处理有发展潜力的净水工艺。     

低温低浊进水下壳聚糖及其衍生物助滤效果研究

针对黄河下游水库水质冬季呈现低温低浊、处理难度大的特点,采用壳聚糖(CTS)、低聚合度壳聚糖(LCTS)、质子化壳聚糖(HCTS)和羧甲基壳聚糖(CMCS)助滤剂进行二次微絮凝过滤模拟实验。结果表明,低温低浊水质下CTS、LCTS、HCTS可有效降低滤池出水浊度,当CTS投加量为0.6 mg/L时,浊度可将至0.1 NTU;质量分数0.2%的稀盐酸代替质量分数1%的冰乙酸溶液溶解CTS可有效解决滤池出水因投加CTS助滤剂引起水中pH降低、滤池出水TOC含量升高等问题;降低进水pH,可提高CTS强化过滤效果;pH为6时,出水浊度降至0.1 NTU左右,颗粒数降至320 CNT/m L。     

陶瓷膜在高浊度给水处理中的试验研究

为了应对给水厂可能存在的高浊度水源风险,研究了陶瓷膜通量的变化规律,以及陶瓷膜过滤对原水浊度、颗粒数的去除效果。结果表明,膜通量基本随膜孔径增大呈上升趋势,过滤初期膜通量下降很快,运行10 min后逐渐稳定。当水源浊度为12 NTU时,4种孔径的膜通量较大,约为500～600L.m-.2h-1;当水源浊度升高为50～500NTU时,4种孔径的膜通量会变小,约为300～400 L.m-.2h-1。陶瓷膜的出水浊度随膜孔径的增大变化不明显,当水源浊度为12～500 NTU时,4种孔径陶瓷膜的出水浊度相近,约为0.1 NTU。>2μm的膜出水颗粒以2～5μm为主,约占总颗粒数的80%。当水源浊度为500 NTU时,5、10 nm孔径膜出水颗粒数变化不大,>2μm颗粒数约为30～80 CNT.mL-1,50、100 nm孔径膜出水>2μm颗粒数分别为215、346 CNT.mL-1。     

新型聚硅铝铁絮凝剂强化处理低温低浊水

以硅酸钠、硫酸、硫酸铝和三氯化铁为原料制备了聚硅铝铁复合絮凝剂,对低温低浊水进行处理研究,并与硫酸铝、PAC进行了对比。结果表明,聚硅铝铁复合絮凝荆对低温低浊水有较好的处理效果,投加量为4mg／L时,出水浊度在0．5NTU以下。     

超滤膜直接过滤处理低温低浊水的试验

中试采用超滤膜直接过滤处理低温低浊水,考察了超滤膜的除污性能和影响膜污染的各种因素。结果表明超滤膜直接过滤的出水浊度恒低于0．1 NTU,对COD和UV254的平均去除率分别为17％和14％;处理水量越低,过滤周期越短,反洗强度越大,跨膜压差（TMP）增长越缓慢,越有助于缓解膜污染,使超滤膜系统能够长时间稳定运行;低温对膜污染的影响不容忽视。     

废纸浆对聚合氯化铝处理低浊水的助凝效果研究

以废纸浆为助凝剂,通过混凝沉淀烧杯实验研究其对聚合氯化铝(PAC)的助凝效果及处理低浊水的适应性。结果表明,当原水浊度为21.8 NTU,PAC投加量为10 mg/L时,适宜的废纸浆投加量为20 mg/L,处理后出水浊度为2.89 NTU,相比单独使用PAC的出水浊度降低47%。废纸浆宜在快速搅拌前投加,并采用100 r/min的速度进行中速搅拌,其对较高浊度和弱碱性的低浊水有更好的助凝效果。废纸浆的使用能够提高浊度去除率,降低COD_(Mn)和铝、铁含量,且出水的多数水质指标已能满足GB 5749-2006要求,可以作为一种高效、安全、多功能的净水助凝剂。     

聚合双酸铝铁对低浊水的处理效果研究

采用混凝沉淀烧杯实验研究聚合双酸铝铁(PAFCS)对低浊水的处理效果和适应性。单因素实验结果表明,当原水浊度为5.85~19.20 NTU,水温为12~14℃时,适宜的处理条件为:聚合双酸铝铁投加量为20 mg·L~(-1),搅拌方式为300r·min~(-1)搅拌1min,150r·min~(-1)搅拌5min,50r·min~(-1)搅拌5min,沉淀时间为20min,相应的出水浊度为0.93~3.55NTU,浊度去除率为77.81%~89.01%;且较高浊度和中性偏碱性条件有利于提高处理效果。而正交实验结果表明,影响聚合双酸铝铁对低浊水处理效果的因素主次顺序是pH值大于沉淀时间聚合双酸铝铁投加量搅拌方式。     

大庆石化循环水旁滤系统采用高效流砂过滤器中试研究

介绍了流砂微絮凝过滤用于石油化工厂循环水旁滤系统的试验研究.试验结果表明,投加10mg·L-1聚合氯化铝(PAC)时,出水浊度很稳定,进水浊度在6～9 NTU时,出水浊度维持在3 NTU以下.投加聚合氯化铝铁(PBACF)的出水浊度没有投加PAC时的稳定.试验同时表明,循环水旁滤系统采用流砂过滤器,并投加适量的聚合铝盐,能够获得稳定的出水浊度.     

高锰酸钾及高铁酸钾预氧化及A113对低温低浊水的混凝效果

针对宁夏宁东水厂冬季低温低浊水处理困难的问题,研究了高锰酸钾和高铁酸钾预氧化对混凝效果的影响以及提纯A113,在处理低温低浊水时的优势。结果表明在PAC投加量一定的情况下,高铁酸钾和高锰酸钾先于PAC投加对浊度和的去除效果最好,其次是同时投加,最次是二者后于PAC投加;高锰酸钾和高铁酸钾都有最优的投加量,投加量过多或者过少都会对混凝效果产生影响;pH对高锰酸钾和高铁酸钾预氧化具有重要的影响,酸性条件下高锰酸钾和高铁酸钾的预氧化效果较好;提纯的A113,在处理低温低浊水时混凝沉后水浊度较常规混凝剂有明显的降低（1NTU以下）。     

沉淀池污泥回流强化低浊水处理研究

采用沉淀池排泥水回流的方法以强化净水厂低浊水混凝处理效果,进行了影响因素的研究,并应用于实际工程中。结果表明,当原水浊度在5~10 NTU,p H在8.0左右,回流排泥水浊度为281.2 NTU,回流体积比为5%,PAC投加量为18 mg/L时,浊度去除效果最好。在低投加量的情况下,回流排泥水后,除浊效果较为明显,可较大程度的节约投加量。该技术在孝感某水厂运行效果良好,每年可产生至少约150.96万元的经济效益。     

Contact Ratio: A New Precise Measurement for Wettability

According to Young's equation, the contact angle “Θ” is considered as the measurable wettability parameter. The rate of change in the contact angle has been commonly used as the relevant parameter of spreading dynamics notwithstanding the difficulties associated with contact angle measurements that are well recognized in the literature. Considering that the velocity of the contact line is the pertinent quantity, it is, therefore, reasonable to regard the change in the contact area as the flux of the process. In this study, we have introduced a new measuring parameter for wettability based on the liquid/solid contact area. The term “contact ratio” has been coined to account for this new measurable parameter. The contact ratio is defined as the ratio between the spreading contact area of liquid over solid surface and the surface area of the spherical drop before spreading. The measurements of contact areas and low‐rate dynamic contact angles for various liquid/solid systems were conducted independently using the ADSA‐P technique. The theoretical relation between the contact ratio and the contact angle is derived based on spherical cap approximation. The results show that there is a good correlation between the theoretical relation and the experimental values. Since the contact angle of a specific system is a unique parameter of the system, the contact ratio can also be presented as a unique parameter of the system. Nevertheless, contact ratio presents a more precise measure of wettability.     

Revisit the adhesive contact between a nanoscale rigid sphere and an elastic half-space: considering the effect of sphere size

The current paper revisits the adhesive contact between a rigid nanoscale sphere and an elastic half-space. Using analytical solution for traction and a modified numerical scheme, a new simulation is proposed. The adhesive contact is simulated faster and more easily than previous researches. The effect of sphere size is investigated. A modified spherical JKR model and spherical DMT model are proposed. The results are compared with spherical JKR, spherical DMT, and rigid sphere model. The load–approach and contact radius–load relations can be predicted by the modified spherical JKR model for sphere radius larger than 50?. Finally, approximation equations for pull-off force vs. Tabor parameter and jump-in distance vs. Tabor parameter are proposed.     

Microscopic studies of static and dynamic contact angles

Molecular dynamics simulations are used to test macroscopic theories for static and dynamic contact angles. Young's equation is verified by comparing observed static contact angles to angles calculated from the independently measured surface tensions between phases. Laplace's relation between the interfacial curvature and pressure is also checked. Both equations agree with simulation results within statistical errors. Hydrodynamic theories of dynamic contact angles are less well defined because they produce diverging stresses at the contact line between the solid and fluid interfaces if the usual no-slip boundary condition is assumed. Our simulations show that slip occurs within about two molecular diameters of the contact line, and that local hydrodynamics breaks down in the slip region. The slip results from large tangential stresses along the solid wall. A surprising result is that changes in the boundary condition for single-fluid flow at molecular scales produce dramatic changes in the dynamic contact angle.     

水解酸化/接触氧化/接触沉淀工艺处理小区生活污水

惠州市某高级住宅小区生活污水处理站采用了水解酸化/接触氧化/接触沉淀工艺,该处理工艺具有耐冲击能力强,水力停留时间短,污泥产生量少,操作简单,运行出水稳定等特点,出水水质达到《广东省地方标准水污染物排放限值》（DB44/26-2001）的第二时段一级标准。     

轮胎接触问题的分析与研究

简要地综述了轮胎接触问题分析的发展过程及所使用的一些方法，着重介绍了三维有限元法在轮胎接触问题中的应用，同时也概括了弹性力学理论及实验测试在轮胎接触问题中的应用。本文对轮胎接触问题的分析主要是围绕静态接触和滚动接触两方面展开论述的，列出了轮胎接触问题中轮胎变形、接触区形状大小、接触压力分布、应力分布、载荷变形关系、内轮廓形状等结果     

角膜接触镜材料透氧性能的研究进展

角膜接触镜的透氧性及配载角膜接触后角膜的获氧状态，是保证配戴安全性和有效性的关键。本文就角膜接触镜的透氧性能及角膜缺氧时可能引起的症状进行了综述。     

A New Approach to Contact Drying Modelling

This paper deals with contact drying modelling. The more general models of granular material contact dryers are based on assumptions proposed by Schlunder and al. (1.21. In this paper, a sensitivity study of the models is presented in order to find and to explain the influence of the different arameters.

A new approach, based on the same Schlunder's assumptions, but with less restrictive hypothesis, which can be applied to drying in the presence of an inert gas as well as vacuum drying and which take into account phenomena which were ignored untill now such as the local grain dehydration kinetics or the vapour diffusion inside the bed has been developped.

This new model has been compared uith some experimental results found in the litterature. A good agreement between the calculated and the experimental results has been observed. Moreover, this model is able to justify some assumptions made by Schlunder, which have not been so untill now.     

A New Approach to Contact Drying Modelling

ABSTRACT

This paper deals with contact drying modelling. The more general models of granular material contact dryers are based on assumptions proposed by Schlunder and al. (1.21. In this paper, a sensitivity study of the models is presented in order to find and to explain the influence of the different arameters.

A new approach, based on the same Schlunder's assumptions, but with less restrictive hypothesis, which can be applied to drying in the presence of an inert gas as well as vacuum drying and which take into account phenomena which were ignored untill now such as the local grain dehydration kinetics or the vapour diffusion inside the bed has been developped.

This new model has been compared uith some experimental results found in the litterature. A good agreement between the calculated and the experimental results has been observed. Moreover, this model is able to justify some assumptions made by Schlunder, which have not been so untill now.     

The Importance of Bonded Structural Material

Gluing is of tremendous importance to the wood industry. About 70% of all wood used today involves gluing. As an increasing amount of lower quality wood is used in the future, gluing will become even more important. Additional developments in harvesting previously unused species and forest residues and cleaning dirty material, and a means to reclaim urban waste wood, are needed to assure an adequate wood supply. New or improved economical adhesive systems will be important in accelerating the development of glued products. The future of the wood products industry lies with the use of glue, since the wood raw material will continue to be harvested in ever smaller sizes.     

An Attachment Theory for Microsphere Adhesion

A theory of the mechanics of adhesion between a microsphere and substrate is presented. When a force is applied to an elastic body, the deformation depends not only on the magnitude of the force but also its location and distribution. Molecular adhesion between bodies is a surface force localized to the contact area. In contrast, applied forces such as from gravity, flow fields, inertia, etc., are distributed over the volume (body forces) and/or surface areas. Effects of different types of force systems on deformation, particularly when these forces are combined, can influence adhesion. The Hertzian structural stiffness parameter K does not reflect the effects of differently distributed multiple forces. A theory is developed that takes into account simultaneous application of the adhesion force and applied forces through the development of a reduced stiffness, K_R. The paper also develops an equivalent Hertzian process for the condition of adhesion forces alone so that the mechanics of adhesion can be modeled completely by Hertzian theory. Illustrations of how adhesion alone is handled and how the reduced stiffness behaves are provided using experimental data from compressed, crossed rods and from hard particles in static equilibrium with both relatively hard and soft substrates.