气提有机管式膜工艺精制卤水研究

采用气提有机管式膜过滤工艺进行卤水精制,研究了曝气量、膜面流速、跨膜压差、背压、反洗强度对膜通量的影响,并计算了过滤阻力及系统能耗.实验结果表明随着系统曝气量、跨膜压差、背压的增大,膜通量增加,而膜面流速对膜通量影响较小,反洗周期定为15min.计算结果表明,与错流过滤工艺相比,该工艺利用气液两相流的不稳定性能有效降低膜过滤阻力,并显著降低能耗.     

基于跨膜压差变化特征的膜生物反应器曝气条件的优化

采用膜生物反应器对石化废水进行处理,在300L/h,150L/h及75L/h三个曝气量下,研究跨膜压差及单周期跨膜压差变化率(K)的变化特征.试验结果表明:跨膜压差呈指数型曲线变化,跨膜压差与运行时间的关系式为:ΔP=Aebt.不同曝气量下,单周期跨膜压差变化率K的变化范围为0~2.5Pa/s,曝气量的改变并不能改变K值增大的趋势.但是,曝气量对K值变化特征有影响,在提高曝气量的条件下,K上升的速率较缓.可依据单周期跨膜压差变化率K的变化趋势,对膜生物反应器的曝气进行过程控制,并同步减缓膜污染的进程.     

陶瓷微滤膜滤除骨架镍催化剂微粒的研究

提出用陶瓷微滤膜脱除骨架镍催化剂微粒的方法,研究了操作压差、膜面流速、温度和料液浓度等操作条件对膜通量的影响,确定了简单而有效的膜清洗方法与合适的操作条件.结果表明,在本实验中膜的污染现象不严重,主要的膜过滤阻力来自形成的滤饼层,采用平均孔径0.2μm的陶瓷膜,在合适的操作条件下,膜稳定通量为1050L/(m2·h),渗透液中镍含量小于3mg/L,截留率满足了化工产品质量要求.     

用动态膜技术回收半导体加工中的含硅废水

应用动态膜技术回收半导体厂晶片切割废水,研究了动态膜的形成条件及其水处理效果.通过恒压过滤形成动态膜:恒压过滤压差5 kPa,曝气强度10 L/min,过滤高浓度(TS＝1 800 mg/L)含硅废水,形成了均匀而阻力较小的动态膜;之后在一定的过滤运行条件下,研究膜过滤低浓度晶片切割废水的运行周期和水处理效果:要处理的废水TS(总固形物)=40mg/L,恒速过滤滤速为0.6 m/d,曝气量为15 L/min.结果表明:该动态膜可保护基膜不被污染,维持较长的过滤周期,稳定运行时间达260～360 h.膜过滤单元中的TS(总固形物)可被浓缩达到1 200 mg/L.动态膜对原水浊度、TS的去除效果很好,产水水质稳定,浊度为0.14NTU,TS几乎为0,SDI15为0.5,电导率为12μS/cm,满足反渗透深度处理的进水要求.当压力上升至14 kPa时,排出浓缩液、用产水冲刷清洗基膜表面的滤饼层,以回收高纯硅,同时基膜经过擦洗后通量可以完全恢复.     

气液两相流下膜的抗污染性能研究

膜表面浓差极化与滤饼层形成是膜污染的重要因素.通过管式膜曝气,使膜表面形成气液两相流,增大膜表面剪切力,能有效控制膜污染行为.实验通过微滤高岭土悬浊液,观察了不同曝气量下膜组件内气液流态,发现随着曝气量的增加,膜组件内气泡单元上升速率和频率加快,膜污染速率逐渐减小,延长了膜过滤运行时间.研究发现,气体的通入使膜表面湍流程度增大,有效减缓跨膜压力增长速率,并且实现了在较低流速下控制膜污染,节省了能耗成本,延长了膜使用寿命.     

新型聚醚砜/磺化聚醚砜共混超滤膜制备方法的研究

基于自制的磺化聚醚砜(SPES)溶液,直接将SPES溶液与聚醚砜(PES)共混配制铸膜液,制备新型的聚醚砜/磺化聚醚砜(PES/SPES)共混超滤膜,简化了制膜过程.考察了铸膜液中PES与SPES总固含量、凝固浴温度、预蒸发时间和添加剂对PES/SPES共混膜结构与性能的影响.研究发现,随铸膜液温度的降低和铸膜液中酸含量的增加,铸膜液的比浓黏度增加;制备的共混膜断面为致密皮层和多孔支撑层组成的不对称结构;随铸膜液PES/SPES总固含量的增加,共混膜的水通量降低,截留率升高;随凝固浴温度升高和预放置时间延长,共混膜水通量增加,截留率降低;聚乙二醇200(PEG200)和丙酮的加入有利于改善膜性能,当加入量为2%时,共混膜的水通量都高于460L/(m~2·h),对PEG6000截留率都大于85%.     

疏水陶瓷膜脱除油中水分的研究

对采用平均孔径50nm、表面疏水的陶瓷膜脱除油中水分的过程进行了研究,考察了跨膜压差、膜面流速、原料液水含量对膜渗透通量及水截留率的影响.结果表明,采用疏水陶瓷膜脱除异辛烷中水分可得到较好的分离效果;增大跨膜压差或减小原料液水含量可以增加膜稳定通量,而随着膜面流速的增加,膜稳定通量先升后降.实验得出适宜的操作参数为跨膜压差0.1MPa、膜面流速1.67m/s,获得的水截留率均在98%以上.基于所用陶瓷膜稳定的亲油疏水表面,渗透侧水含量在不同的操作条件下变化很小.     

聚氯乙烯接枝烯丙基聚乙二醇的制备及成膜性能

以氯化亚铜(CuCl)/2,2'-联吡啶(BPy)为催化配位体系,N,N-二甲基乙酰胺(DMAc)作为溶剂,通过原子转移自由基聚合(ATRP)法在聚氯乙烯(PVC)分子链上接枝烯丙基聚乙二醇(APEG)。X射线光电子能谱(XPS)、红外光谱(FT-IR)和核磁共振(1H-NMR)表明:APEG单体成功地接枝到了PVC链上;改性材料经相分离法制备过滤膜,膜的孔径分布范围为0.117μm~0.247μm,接触角在300 s内由81°下降至64.4°;0.05 MPa跨膜压差下,初始纯水通量为1677 L/(m2·h);牛血清蛋白(BSA)液过滤试验共循环3次,0.05 MPa跨膜压差下,首次循环初始通量为737 L/(m2·h),经3次循环后BSA通量稳定在101 L/(m2·h),显示出较好的抗污染性能。     

微滤膜过滤阻力机理及模型研究

研究微滤膜过滤阻力机理及其通量的变化是该工艺应用推广需要解决的关键.以Langmuir理论和Darcy定律为基础,从理论上证实了浓度极化阻力与凝胶层阻力是同一性质的阻力,并通过Langmuir关系式统一起来,推导了微滤膜过滤阻力的数学模型.然后采用一体式膜过滤反应器过滤乳化油实验对该模型进行了验证.实验结果与膜过滤阻力模型拟合得很好(R2=0.9912),膜表面极化浓度与相对过滤压差成线性关系,比例系数为凝胶层浓度.基于Langmuir理论的微滤膜过滤阻力模型能真实反映凝胶层阻力的形成过程.用该模型得到的沉积平衡系数Φ反映了混合液的浓度、颗粒大小、温度和黏度等过滤特性,并把极限通量JVlim与混合液过滤特性联系起来,极限通量与过滤压差无关.     

海藻酸钙水凝胶过滤膜的制备及其对硫酸钙的截留

以尿素为致孔剂制备了海藻酸钙(CA)水凝胶过滤膜,测试了其通量、截留率和力学性能;通过扫描电子显微镜(SEM)观测其过滤硫酸钙前后的表面形貌。结果表明,增加尿素含量,均导致膜应力和应变的下降;而膜的纯水通量则迅速增大,尿素含量为3.0%(质量分数)时达到28.7 L/(m2·h),为最大;0.2 MPa下,过滤1.7 g/L硫酸钙时对Ca2+和SO2-4的截留率分别为83%和92%,稳定通量达到21.7 L/(m2·h)。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from