Triboelectrostatic separation of granular plastics mixtures from waste electric and electronic equipment

The efficiency of the electrostatic separation of insulating granular mixtures depends on the electric charge carried by the particles. The first objective of this work was to characterize the tribocharging properties of various plastic materials in the composition of waste electric and electronic equipment: polyvinyl chloride (PVC), “high-impact” polystyrene (HIPS), acrylonitrile butadiene styrene (ABS), “high-density” polyethylene (HDPE), polycarbonate (PC), polyamide (PA). Thus, in a first series of experiments, 15 samples composed of binary mixtures of above plastics were initially charged in a fluidized bed device, then separated using a free-fall electrostatic separator. The six plastics could be ordered in a specific triboelectric series: PVC, HIPS, ABS, PEHD, PC, PA. The second objective was to evaluate the efficiency of three tribocharging devices: a static charger, a fluidized bed, and a fan-type device. The triboelectrostatic separation experiments performed with four different binary mixtures (PVC/PA, PC/PA, HIPS/PA, and HIPS/ABS) showed that the fluidized bed is the most effective.     

聚醚砜四元制膜液体系的相图计算

以Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论为基础，对ＰＥＳ－ＰＧ－ＮＭＰ＿Ｈ２Ｏ＿）聚醚砜丙二醇－Ｎ－甲基－２－哟咯烷酮水）四元制液体系的相图进行了计算，利用三元相图考察Ｈ２Ｏ和ＰＧ对液－液相分离的影响，在三元的理论的基础上提出了低分子量添加剂的卤元改性Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论，并提出了一种获得四元相图的方法，利用四元相图能较争地描述四元体系，利用改性的四元理论，能了地理解该种体系的液－液相分离行为。     

Monte Carlo simulation of the homogeneous cooling state for a granular mixture

 The Direct Simulation Monte Carlo (DSMC) method is used to numerically solve the Enskog equation for a granular binary mixture in the homogeneous cooling state (HCS). The fourth velocity moments, the temperature ratio, and also the velocity distribution functions are obtained and compared with approximate analytical results derived recently from a Sonine polynomial expansion [V. Garzó and J. W. Dufty, Phys. Rev. E 60, 5706 (1999)]. The comparison shows an excellent agreement between both approaches, even for strong dissipation or disparate values of the mechanical parameters of the mixture. In contrast to previous studies, the partial temperatures of each species are clearly different, so that the total energy is not equally distributed between both species. Finally, in the same way as in the one-component case, the simulation as well as the theory show a high energy tail of the distribution functions. Received: 9 May 2001     

Effect of energy nonequipartition on the transport properties in a granular mixture

The Boltzmann kinetic theory is used to analyze the effect of energy nonequipartition on the pressure and the shear viscosity of a granular binary mixture under simple shear flow. Theory and Monte Carlo simulations show that both quantities exhibit a non–monotonic behaviour with the mass ratio in contrast to the predictions made from previous theories based on the equipartition assumption. Our results agree qualitatively well with recent molecular dynamics simulations performed by Alam and Luding [Granular Matter 4, 139 (2002)]. The authors acknowledge partial support from the MCYT (Spain) through Grants No. BFM2001-0718 and ESP2003-02859.     

高分子季铵盐型抗菌塑料的制备和抗菌性能

采用共价键合方法将高分子季铵盐接枝在纳米SiO2粉体表面,其抗细菌效果与无机载银抗菌剂相当,对金黄色葡萄球菌和大肠杆菌的最小抑菌浓度分别为100 mg/L和1500 mg/L.使用抗菌剂母粒化法将其添加到聚乙烯(PE)中制备抗菌塑料,抗菌粉体均匀分散在塑料的外层,平均粒径为200 nm.抗菌塑料对细菌和霉菌的抗菌效果都非常显著,其防霉性能明显优于由无机载银抗菌剂制备的抗菌塑料.抗菌塑料人工老化处理不会使其抗菌效果明显下降,具有良好的抗菌长效性和稳定性.     

Global behavior of the diffusion coefficient for the Van Der Waals binary mixture

We describe the general dependence of the diffusion coefficient associated with the Van der Waals binary mixture on the temperature, number densities, and relative strengths of molecular interaction parameters. The task is facilitated by the fact that for Kac-type intermolecular potentials, in the long-range limit, the diffusion coefficient becomes simply related to the product of a partial compressibility and the curvature of the equilibrium free energy in the space of number densities. Therefore the different kinds of behavior found can be classified according to the scheme of Scott and Van Konynenburg for the global phase diagram of the same model mixture.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

醇/醚混合物渗透汽化分离膜的研究进展

针对醇 /醚混合物的渗透汽化分离 ,提出了分离膜材料及其分离性能 ,讨论了操作条件对分离性能的影响 .     

宽带盲波束形成与卷积混合盲源分离

盲波束形成是在不知道阵形，目标方位以及阵元响应等信息的情况下，只根据阵元输出恢复源信号。现有盲波束形成对窄带信号研究比较多。而对宽带信号盲波束形成论述较少。本文从信号模型，系统框图。处理的三方面说明盲波束形成与盲源分离近似，并指出卷积混合模型盲源分离完全可以作为解决宽带信号盲波束形成问题的一种通用方法。     

基于核典型相关分析的非线性相关源盲分离方法研究

针对传统的相关源盲分离方法的不足,提出了一种基于核典型相关分析的非线性相关源盲分离方法。该方法是利用了核方法来处理数据之间的非线性问题,同时还利用信号源之间的相关性来进行分离。提出的方法与传统的相关源盲分离方法进行对比分析。仿真结果表明,提出的方法明显优于传统的相关源盲分离方法,并从分离性能指标上得到了充分的反映。最后,将该方法应用到转子不对中和碰摩故障的盲分离中,实验结果进一步验证了该方法的有效性。     

灰斗抽气对旋风分离器分离性能影响数值模拟研究

 利用计算流体动力学软件FLUENT对旋风分离器内气固两相流动特性进行三维数值模拟,模拟气相流场采用雷诺应力模型,应用随机轨道模型模拟湍流流场中颗粒的运动轨迹,同时给出了不同抽气率下旋风分离器的速度、压力分布,计算出旋风器分级效率,模拟结果与文献实验数据吻合较好.结果表明,灰斗抽气可以提高锥体内旋转气流切向速度,轴向速度减少能够降低气流携带颗粒返混能力,并减小排气芯管下口短路流,提高旋风分离器分离效率.对于给定的旋风分离器,抽气率应有一最优值.     

噪声环境下水声信号瞬时盲源分离方法研究

噪声环境下大多数盲源分离算法性能大大降低。提出了一种适用于噪声环境的基于子带分解的瞬时盲源分离算法。通过修正白化矩阵和选取合理子带降低盲源分离过程中由噪声产生的不利影响。仿真实验表明,采用基于子带分解的瞬时盲源分离算法能够较好地实现噪声环境下水声混合信号的分离;进一步研究表明,该算法在噪声环境下表现出良好的稳健性。     

Energy and exergy analysis of zeotropic mixture R290/R600a vapor-compression refrigeration cycle with separation condensation

This paper proposes a modified vapor-compression refrigeration cycle (MVRC) system operating with the zeotropic mixture R290/R600a for domestic refrigerator-freezers. In the MVRC system, a phase separator is introduced to enhance the overall system performance. A theoretical energy and exergy analysis on the performance of the MVRC is carried out by using the developed mathematical model, and then compared with that of the traditional vapor-compression refrigeration cycle (TVRC) operating with the refrigerant R600a and the zeotropic mixture R290/R600a, respectively. According to the simulation results of these two cycles, the MVRC can give the most excellent performances in the COP (coefficient of performance), the volumetric refrigeration capacity, the total exergy destruction and the exergetic efficiency under the same given operating conditions. Therefore, the performance characteristics of the MVRC may show its promise in domestic refrigerator-freezer applications.     

5000m~3/h空分设备液氮气液分离器运行控制分析

简介仪征化纤5000 m3/h空分设备中液氮气液分离器的工作原理和作用,分析气液分离器的工作状态及其对空分设备主塔运行工况的影响,论述用压力控制气液分离器工作状态的可行性,阐述其工作状态控制方法的改造建议。     

自动复叠系统中非共沸混合制冷剂的组分分离

自动复叠系统利用单压缩机多元混合制冷剂来制取低于-60℃的低温。在循环过程中,混合制冷剂分离的好坏直接影响到系统的各部分性能。如何更好地分离各制冷剂组分成为一个重要的课题。本文综述自动复叠系统中选择非共沸混合制冷剂时需要考虑的问题,并讲述几种非共沸混合制冷剂组分分离的方式,提出分离程度与制冷量之间的关系。     

循环流化床锅炉用旋风分离器性能的实验研究

结合水煤浆流化-悬浮燃烧的特点,通过全面测定循环流化床锅炉用旋风分离器在不同操作参数下的分离效率,研究了入口气速、入口颗粒浓度、入口颗粒物性等对旋风分离器的压降和分离性能的影响规律。实验结果表明,影响旋风分离器分离性能的主要物性参数是颗粒的中位粒径、密度,在入口颗粒的中位粒径相差较大时分离性能主要受粒径的影响,而当入口颗粒粒径相差较小时密度对分离器分离性能的影响则更为显著。     

有机混合物渗透汽化膜分离及过程开发研究进展

在分析渗透汽化膜分离有机混合物体系类的基础上，提出了重点分离的有机混合物体系，介绍了固载功能基团膜的研究现状以及它们的传递机理，并简要地讨论了渗透汽化与其他技术相结合的集成过程开发。     

Nonparametric variational learning of multivariate beta mixture models in medical applications

Clustering as an essential technique has matured into a capable solution to address the gap between the growing availability of data and deriving the knowledge from them. In this paper, we propose a novel clustering method “variational learning of infinite multivariate Beta mixture models.” The motivation behind proposing this technique is the flexibility of mixture models to fit the data. This approach has the capability to infer the model complexity and estimate model parameters from the observed data automatically. Moreover, as a label‐free method, it could also address the problem of high costs of medical data labeling, which can be undertaken just by medical experts. The performance of the model is evaluated on real medical applications and compared with other similar alternatives. We demonstrate the ability of our proposed method to outperform widely used methods in the field as it has been shown in experimental results.     

Viscosity of a phase-separating critical mixture

Onuki has predicted the existence of a significant enhancement of the viscosity of a liquid mixture in the course of spinodal decomposition. We discuss a method to measure this effect in a critical mixture of isobutyric acid and water in which spinodal decomposition is induced by a pressure-quench technique. In addition, by varying the static pressure in the homogeneous phase, experimental information about the dynamic critical exponent for the viscosity is obtained.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

Direct observation of critical fluctuations in a binary mixture

Microscopic observations of concentration fluctuations in the range 1–500 m have been performed in a number of binary fluids near their critical temperature (T _c). A heterodyne technique has been used. The temperature range (T-T _c = 1–25 mK) is such that the sizes of the fluctuations are larger than or equal to the correlation length, measured usually as the inverse half-width of the structure factor of the fluctuations. Image analysis has given some information about the free energy of the system determined from the intensity distribution function. Also, the shape of the fluctuations can be studied. These are self-similar over more than three decades, with a fractal dimension of D _f = 2.8. This value is compared with a number of theoretical predictions.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

动力/储能锂离子电池隔膜制备先进技术及研究进展

锂离子电池主要由电极、隔膜、电解液三大部分构成。其中隔膜作为电池的关键部件之一,极大地影响着电池的综合性能。商业聚烯烃隔膜由于润湿性与耐温性差、孔隙率低等缺点,很难满足高性能锂离子电池隔膜的要求。因此,隔膜的制备技术与材料急需进行深入的研究与探索。本文从近期隔膜的研究热点出发,分别从商业聚烯烃隔膜的改性、静电纺丝法及相分离法制备等方面对动力/储能锂离子电池隔膜最新研究成果进行综述,并指出了未来隔膜的发展方向。