异相粒子填充聚合物分离膜

膜技术的快速发展对膜性能的要求也越来越高。异相粒子填充制膜扩大了膜材料的选择范围,改善了膜的多种性能,并且为制备特种分离膜提供了一种较为简便的方法。文中从异相粒子填充聚合物分离膜的特点、性能、制备方法和孔的形成机理等几个方面在国内外发展现状进行了评述。     

Anticipating Cutoff Diameters in Deterministic Lateral Displacement (DLD) Microfluidic Devices for an Optimized Particle Separation

Deterministic lateral displacement (DLD) devices enable to separate nanometer to micrometer‐sized particles around a cutoff diameter, during their transport through a microfluidic channel with slanted rows of pillars. In order to design appropriate DLD geometries for specific separation sizes, robust models are required to anticipate the value of the cutoff diameter. So far, the proposed models result in a single cutoff diameter for a given DLD geometry. This paper shows that the cutoff diameter actually varies along the DLD channel, especially in narrow pillar arrays. Experimental and numerical results reveal that the variation of the cutoff diameter is induced by boundary effects at the channel side walls, called the wall effect. The wall effect generates unexpected particle trajectories that may compromise the separation efficiency. In order to anticipate the wall effect when designing DLD devices, a predictive model is proposed in this work and has been validated experimentally. In addition to the usual geometrical parameters, a new parameter, the number of pillars in the channel cross dimension, is considered in this model to investigate its influence on the particle trajectories.     

PEPT Investigation of Particle Separation in a Novel Vertically Vibrated Particle Separator

Separation of particle mixtures in micron size range is of concern to many industrial processes. The experimental work presented in this article has looked into the operational assessment of a novel vertical vibration driven particle separator by using a positron emission particle tracking (PEPT) technique. In addition to PEPT, a smoke blanket visualization technique was used to track the intestinal air movements during the course of vibration induced particle separation. Three different finely sized glass and bronze particle mixtures that formed an average particle bed heights of 20, 40, 60, 80, and 100 mm in separation cells of thickness 20 and 40 mm were used to investigate the particle separation behavior. For a range of operating conditions, the results showed in favor of low particle bed heights (below 40 mm), lower vibration frequency (30 ± 10% Hz) and a small partition separation gap size of 5 mm for optimum separation of bronze particles in the presence of air.     

导叶式旋风管入口颗粒粒度分布对分离效率的影响

为深入研究导叶式旋风管的分离机理,用不同粒度分布的SiO2颗粒对分离总效率与粒级效率进行了对比研究。实验结果表明:入口颗粒的粒度分布不但对旋风管的分离总效率有影响,而且对粒级效率也有较大影响;不同粒径大小的颗粒在旋风管中的分离机理不同。     

Particle Characteristics and Analysis Using the Laser-Based Phase Doppler Particle Analyzer (PDPA) and Statistical Method

Particle characterization is an important component in product research and development, manufacturing, and quality control of particulate materials. In this article a laser-based phase Doppler particle analyzer (PDPA) was used to measure particle size and velocity. Two different particles, humid particles and fog particles, were tested using the PDPA. Several tests were conducted under different conditions and all data were analyzed using the statistical method and analysis of variance (ANOVA) to see which factor affects particle performance. The humid particle flow rate has a significant effect on both the particle mean diameter and the particle mean velocity with 90% confidence. The type of oil particle has a significant effect on the particle mean velocity with 90% confidence.     

Particle Characteristics and Analysis Using a Laser-Based Phase Doppler Particle Analyzer (PDPA) and Statistical Method

Particle characterization is an important component in product research and development, manufacturing, and quality control of particulate materials. In this study a laser-based phase Doppler particle analyzer (PDPA) was used to measure particle size and velocity. Two different particles including humid particles and fog particles were tested using the PDPA. Several tests were conducted under different conditions and all data were analyzed using the statistical method and analysis of variance (ANOVA) to see which factor affects particle performance. The humid particle flow rate has a significant effect on both the particle mean diameter and the particle mean velocity with 90% confidence. The type of oil particles has a significant effect on the particle mean velocity with 90% confidence.     

Separation of H(2)SO(4) + CuSO(4) mixture by diffusion dialysis

Diffusion dialysis of aqueous solution of H(2)SO(4) + CuSO(4) has been investigated in a two-compartment cell with an anion-exchange membrane Neosepta-AFN. The experiments have proved that sulfuric acid permeates well through the membrane used, while cupric sulfate is efficiently rejected. This operation is very effective at high acid concentrations and low concentrations of cupric sulfate. Furthermore, it has been found that even at the highest concentration of CuSO(4), the rejection coefficient is higher than 0.965. The flux of CuSO(4) calculated from the time dependences of the CuSO(4) concentration is negatively influenced by increasing acid concentration.     

Separation of Am(III) and Pu(IV) at Their Joint Oxalate Precipitation

A procedure was developed for purification of plutonium to remove americium by oxalate precipitation using diethyl oxalate as a precipitant. The developed procedure was tested under laboratory conditions and on an enlarged installation. It was shown that the decontamination factor of plutonium from americium can exceed 2 ×10³. The plutonium oxalate precipitate can be dissolved by heating with HNO₃ in the presence of V(V) catalyst and also by electrochemical dissolution at alternating current.     

Particle Separation in an Annular Converging Channel with an Inner Rotating Permeable Baffle

The relation between the separation efficiency of solid particles and the stability of the helical flow of a viscous fluid in a converging channel with an inner rotating permeable cylindrical baffle has been studied. The profiles of the axial and tangential velocities and the separation efficiency of solid particles have been calculated based on the numerical solution of a system of equations describing the hydrodynamics of two-phase media. Analysis of the obtained solutions shows that vortices having an effect on particle separation can appear in the converging channel. Moreover, the larger the size of the converging annular channel, the earlier a loss of stability occurs. It has been found that the formation of vortices is impossible for some flow regimes and, as a result of fluid flow stabilization, the fraction of particles settled on the permeable cylindrical baffle decreases. It has been shown that those regime parameters at which a helical flow exists should be selected for the development of combined action units involving filtering and the separation of the solid dispersed phase.     

关于粉体粒度标样的思考及初步实践

列举了引起不同粒度仪器之间测试结果有差异的各种原因,指出出现差异的必然性.为使测量值统一或可比,应该制备粒度标准样.提出了粒度标样应该具有的特性,同时认为,要制备一种或若干种通用的粒度标样是不现实的,而只能按照各行业的具体特点制备适用于本行业的粒度标样.简单介绍了作者所在单位制备的水泥粒度标样的有关数据.     

Lattice Discrete Particle Modeling (LDPM) of Alkali Silica Reaction (ASR) deterioration of concrete structures

A large number of structures especially in high humidity environments are endangered by Alkali–Silica Reaction (ASR). ASR leads to the formation of an expansive gel that imbibes water over time. The gel expansion causes cracking and consequent deterioration of concrete mechanical behavior in the form of strength and stiffness reduction. In the recent past, many research efforts were directed towards evaluation, modeling and treatment of ASR effects on structures but a comprehensive computational model is still lacking. In this paper, the ASR effect is implemented within the framework of the Lattice Discrete Particle Model (LDPM), which simulates concrete heterogeneous character at the scale of coarse aggregate pieces. The proposed formulation, entitled ASR-LDPM, allows precise and unique modeling of volumetric expansion; expansion anisotropy under applied load; non-uniform cracking distribution; concrete strength and stiffness degradation; alkali ion concentration effect; and temperature effects of concrete subjected to ASR. In addition, a unique advantage of this formulation is its ability to distinguish between the expansion directly related to ASR gel expansion and the one associated with cracking. Simulation of experimental data gathered from the literature demonstrates the ability of ASR-LDPM to predict accurately ASR-induced concrete deterioration.     

模拟移动床色谱(SMBC)分离表没食子儿茶素没食子酸酯(EGCG)的预处理工艺研究

采用乙酸乙酯对茶多酚原料进行预处理,使EGCG得到富集。为模拟移动床分离EGCG作准备。萃取的条件是:萃取剂的配比为V水:V乙酸乙酯=1:3,萃取液的pH值为4,固液比为1:12,萃取次数为2次。     

Discrete Element Modeling (DEM) of the Vertically Vibrated Particle Bed

Discreet element modeling (DEM) is a computational tool used for detailed exploration of dynamic particle bed behaviors. One such application is the analysis of finely sized particle mixtures under the influence of external forces such as vertical vibration, which is difficult, if barely at all accessible for detailed experimental analysis. Here, we examined the differential density dynamic particle bed behaviors, by the application of a modified two dimensional DEM-fluid model that incorporates the gravity and fluid effects, to replicate some of the important experimental based observations of segregation, heaping, tilting, high density particles on top and bottom, and partition cell separation. The simulation results compared favorably with the reported literature on the density segregation attributes such as high density particles on top at vertical vibration frequency of 6.3 and 7 Hz with corresponding dimensionless acceleration magnitude of 1.6 and 2, convection currents at vertical vibration frequency of 30, 40, and 30 with corresponding dimensionless acceleration magnitude of 3.5, 4, and 3, layer separation at vertical vibration frequency of 7 Hz with corresponding dimensionless acceleration magnitude 2 and partition cell separation at vertical vibration frequency of 45 Hz and corresponding dimensionless acceleration magnitude of 2.25 for simulated glass and bronze particle mixture properties.     

Separation of polyvinyl chloride (PVC) from automobile shredder residue (ASR) by froth flotation with ozonation

The purpose of this study is to develop froth flotation to separate polyvinyl chloride (PVC) from automobile shredder residue (ASR) plastic mixtures of variable composition. Some polymers in ASR polymer mixtures have similar density and hydrophobicity with PVC and thus selective flotation of PVC from ASR polymer mixtures cannot be achieved. The present study focused on the surface modification of PVC with ozonation, and then the modified PVC can be separated from other polymers by the following froth flotation. The results of this study indicate that the selective recovery of PVC from real ASR polyethylene tetra pethelate (PET), polymethyl methacrylate (PMMA), polybutyl methacralate (PBMA), ethyl acrylate (EA), polycarbonate (PC) and rubber mixtures can be accomplished in a three-step process involving a gravity separation, ozonation and froth flotation. The rubber was removed from other heavy ASR (PVC, PET, PMMA, PBMA, EA and PC) polymers by froth flotation without mixing. It was found that ozonation process produced the desired difference in contact angle required (from 89.5 to 73.0 degrees ) for separation of PVC from other heavy ASR polymers, whereas the contact angles of other polymers was slightly decreased. The most of the load ASR, i.e. about 72.4% is floated away and 27.6% was settled down. The highest component 96.7% of PVC was recovered in the settled fraction. As a result of this research effort, the surface modification of PVC with ozonation can be efficiently useful to separate the PVC from other similar density ASR mixed polymers.     

Particle growth mechanisms in Ag-ZrO(2) and Au-ZrO(2) granular films obtained by pulsed laser deposition

Thin films consisting of Ag and Au nanoparticles embedded in amorphous ZrO(2) matrix were grown by pulsed laser deposition in a wide range of metal volume concentrations in the dielectric regime (0.08相似文献   

The Research of Blind Source Separation (BSS)in Machinery Fault Diagnosis

1 Introduction：While a machine is running, it will create vibration, and also strong noise. Commonly, when the vibration is more intense, the noise is greater. Just like the vibration signals, the sound signals of the machinery contain affluent facility status information, so the sound signals can also be used in the machinery fault diagnosis. We call the technology the sound fault diagnosis which uses the sound signals in fault diagnosis. Even more, using the sound signal in fault diagnosis…     

用甲基异丁基酮萃取分离锆铪的工艺评价

简要评述了用甲基异丁基酮(MIBK)萃取分离锆铪方法的基本原理、分离工艺和条件、萃取设备.指出,MIBK在硫氰酸体系中萃取分离锆铪分离效果好,技术成熟,可进行规模生产.MIBK法的主要缺点是必须用有毒的SCN-作稀释剂,工艺复杂而冗长,操作不易控制,劳动强度大,收率低.MIBK在水中有较大的溶解度,废液不易处理,给工艺操作和环境带来极大困难.