Method to Characterize the Air Flow and Water Removal Characteristics During Vacuum Dewatering. Part II—Analysis and Characterization

This is part II of a study reported earlier on a method to characterize the air flow and water removal characteristics during vacuum dewatering. This article presents experimental data and analysis of results from the use of a cyclically actuated vacuum dewatering device for removing moisture from wetted porous materials such as paper with the intermittent application of vacuum and accompanying air flow though the material. Results presented include sheet moisture content as a function of residence time and hence water removal rate under a variety of process conditions. Also, experimental results on air flow through the wet porous structure and hence the role and importance of air flow during vacuum dewatering are presented. Vacuum dewatering process conditions include exit solids content between 11 and 20% solid under applied vacuum conditions of 13.5 to 67.7 kPa (4 to 20 in. Hg). Regression analysis indicated that the exit sheet moisture content exhibited a nonlinear relationship with residence time with exit solids reaching a plateau after a certain residence time. Final moisture content correlated linearly with the average overall flow rate of air through the paper sample and the basis weight of the material.     

Evaluating the mixing performance of a ribbon blender

This paper investigates the effects of processing and equipment parameters of a ribbon blender (i.e. loading method of lubricant, fill level, blade speed and blade design) on magnesium stearate homogeneity. A core sampling technique is used to obtain at least one hundred samples per sampling event, which are extracted throughout the blender and yield a thorough characterization of the entire bed. The results presented here can be used as a guideline to develop appropriate blending processes and characterization protocols for ribbon blenders.     

Electrochemical Aspects of Electroosmotic Dewatering of Clay Suspensions

An attempt is made to elucidate the electrochemical aspects of the electroosmotic dewatering (EOD) of clays as reported in some recent work, especially that on interrupted DC power electroosmotic dewatering published by Rabie, Mujumdar and Weber (2). These authors showed that the dewatering by EOD stops after the DC power has been on for several minutes or hours; on interruption of their power and on short-circuiting of the electrodes, conditions can be created again for some further dewatering by DC power EOD. This discovery, of Rabie et al. is interpreted as a fuel cell effect and it is shown that it affords clues to several other electrochemical strategies for the possible enhancement of the efficiency of the EOD by DC power.

Further, the open circuit potentials observed by Rabie et al. (2) on the interruption of DC power are given an electrochemical interpretation which leads to quantitative estimates in agreement with the experimental values.     

青海盐湖镁厂工艺方案探讨

通过对国内外镁冶炼技术的分析,结合青海盐湖提钾后卤液综合利用的实际,提出了采用卤水脱水的先进工艺,获取粒状无水氯化镁原料,然后用高效、节能的大容量无隔板镁电解槽生产金属镁的工艺。     

Reversible changes of the fill factor in the ZnO/CdS/Cu(In,Ga)Se2 solar cells

The reversible persistent changes of the fill factor (FF) induced by the illumination and voltage bias along with changes in the electronic properties of the ZnO/CdS/Cu(In,Ga)Se₂ photovoltaic devices have been studied. Admittance spectroscopy and capacitance–voltage characterization reveal a correlation between the FF and the space charge distribution within the absorber. Our experiments provide evidence that a major source of FF loss in efficient devices is caused by excess negative charge close to the interface. We explain the persistent changes in the net acceptor concentration in the interface region by the relaxation effects due to compensating donors—the same mechanism, which leads to metastable changes of the doping level in the bulk of the absorber.     

高帧速摄像器

本文介绍了高帧速摄像器的设计、制造、工作和性能。该高帧速有３６０×３６０像素、摄像速度高达５×１０５帧／秒，该摄像器读出电路类似于帧转移ＣＣＤ，由四部分组成     

Dewatering behaviour of water treatment sludges associated with contaminated site remediation in Antarctica

Sludge reduction and dewatering is an important aspect of water and waste water treatment. This is especially true in the case of Australia's Antarctic contaminated site remediation program, where the reduction in volume of wastes to be returned to Australia can lead to significant transport and handling cost savings. The dewatering characterisation of water treatment sludges from an Antarctic contaminated site was conducted using a theory of suspension dewatering developed by Buscall, Landman and White. This theory uses fundamental material properties of compressibility and permeability to determine the diffusivity of a suspension. Diffusivity is a useful property that can be used to directly compare the dewaterability of various sludges. In this investigation, several water treatment sludges were collected and characterised in the field to determine the impact of temperature and additives on compressibility, permeability and diffusivity. The Antarctic sludges were found to be less compressible and less permeable than materials such as mineral suspensions and alum water treatment sludges. Compressibility was found to decrease with the addition of powdered coagulation aids such as bentonite and chitosan.     

湿磨干烧生产线料浆脱水工艺的选择

料浆脱水是湿磨干烧的关键工艺，其脱水方法一般有过滤法，喷浆法和混合法三种，其中过滤法包括真空过滤和加压过滤两种，在国外都有应用，国内则大都用前者。南京院在皖维公司1000t/d生产线和白马山厂850t/d生产经上则采用了厢式压滤脱水法，文中就这两种过滤法的过滤工艺特点及其选择进行了分析和探讨。     

纳米级无机粒子对聚乙烯的增强与增韧

对μｍ级ＣａＣＯ３、ＴｉＯ２和ｎｍ级ＳｉＣ／Ｓｉ３Ｎ４粒子填充ＬＤＰＥ的性能进行了研究。实验证明，μｍ级粒子对ＬＤＰＥ虽无明显的增强增韧作用，但也未使基体的机械性能大幅度下降。ｎｍ级ＳｉＣ／Ｓｉ３Ｎ４对ＬＤＰＥ有较大的增强增韧作用，在５％质量分数时冲击强度出现最大值，缺口冲击强度达５５．７ｋＪ／ｍ２为纯ＬＤＰＥ的２０３％；伸长率到６２５％时仍未断裂，为纯ＬＤＰＥ的５００％，但熔体流动速率急剧下降，仅为纯ＬＤＰＥ的２６％，当含量在３％和１５％质量分数时，熔体流动速率分别为纯ＬＤＰＥ的３３７％和１５１％。     

幸福河倒虹吸基坑降水方法

根据倒虹吸基坑降水实际效果,总结了不同地质情况下的基坑降水方法.比较了截渗墙与管井降水方案,考虑施工要求及降水方案造价,选择管井降水方案.降压采用压力平衡法计算,抽水量采用流量法计算.