纺织空调滤料的性能与应用

探讨纺织空调系统滤料应用现状与性能要求.分析了在纺织空调系统滤料应用中存在的问题.针对除尘滤料的开发,认为滤料应具备除尘效率高、永久阻燃性强、耐用性能好、尘体在滤料表面的静电吸附性低、滤料表面的疏水性能好等性能要求,方能满足纺织空调除尘对滤料性能的要求.     

Investigation of PSt-MWCNT concentration on epoxyacrylate photopolymerization and conductivity of polymer films

Photopolymerization kinetics and conductivity changes of epoxyacrylate composites for various loading modified PSt-MWCNT weight fractions changing from 0.0025 to 0.2 wt.% were evaluated by performing photo differential scanning calorimetry (photo-DSC) and four point conductivity measurements. 0.2% PSt-MWCNT additive polymeric films had their electrical conductivity boosted by 6% more than non-additive polymeric films.     

Fabric filter bag investigation following field testing of sorbent injection for mercury control at TXU's Big Brown Station

Field testing of mercury control sorbent injection options with a TOXECON™ configuration has been completed at TXU's Big Brown Station. Mercury control results at Big Brown were promising and have been previously reported. However, the high air-to-cloth ratio of operations at this unit results in significant differential pressure, and thus there was little operating margin before differential pressure limits were encountered, especially at high loads. This limited the use of sorbent injection as the added material contributes to the overall differential pressure. After field testing, the residual differential pressure across the test fabric filter module had increased relative to baseline conditions to the point that the plant performed a filter change of the test module several months ahead of schedule. An investigation was conducted on pre- and posttest filter samples from the test module and a parallel nontest module to examine the effect of activated carbon injection. Analysis of the samples indicates an increase in residual dust embedded in the filters which appears to explain the low fabric permeabilities. The long-term increase in differential pressure did not appear to be associated with activated carbon injection, but instead was due to a gradual buildup of embedded material on the filters that was not cleaned away by the pulse cleaning system. The injected activated carbon appeared to behave like additional fly ash in terms of baghouse differential pressure but did not appear to accelerate the buildup of residual material.     

Lignite aided dewatering of digested sewage sludge

Mechanical dewatering is commonly used to increase the solids content of municipal sludge prior to its disposal. However, if the rate of filtration is slow, mechanical dewatering can be expensive. In this study, the use of lignite to improve the sludge dewatering is investigated. The effectiveness of lignite conditioning of polyelectrolyte-flocculated sludge is examined using mechanical compression tests. Results show that lignite conditioning in conjunction with polyelectrolyte flocculation gives much better dewatering than the polyelectrolyte flocculation alone. Using Darcy's filtration theory, the specific cake resistance and permeability of the compressed cakes are obtained. Both of these parameters are significantly improved after lignite conditioning. Mercury porosimetry tests on compressed cakes show that the porosity of the lignite-conditioned sludge cake is much higher than that of the polyelectrolyte-flocculated sludge and it increases with increasing doses of lignite. The mercury porosimetry results show that the lignite pore volume of pores greater than 0.5 μm are reduced with increasing sludge ratio indicating that sludge is trapped within these pores, whereas smaller pores are unaffected. The yield stress curves for sludge, lignite and sludge-lignite mixtures show that the sludge filter cake is very compressible, but the lignite-conditioned cake has a range of compressibility which although more than lignite indicate that the cake is relatively incompressible at low pressures. Thus, lignite conditioning acts to maintain the permeability of the filter cake during compression dewatering by resisting cake compression. This leads to a trade-off between the rate of dewatering and the solids content of the compressed cake. With lignite conditioning, the dewatering rate can be increased by a factor of five for the same degree of water removal.     

IMC系统的优化滤波器研究

推荐两种滤波器作为ＩＭＣ系统的滤波器。一种是ＩＴＡＥ滤波器，它符合时间乘绝对误差积分值最小的优化原则，即Ｊ＝│ｅ│ｔｄｔ→ｍｉｎ。另一种是Ｂｕｔｔｅｒｗｏｒｔｈ滤波器，它具有很好的理想低通滤波器特性。由于这两种滤波器的全部结构极点均处于Ｓ复平面的高稳定性区域，又是按最优原理确定其参数，因此，采用这两种滤波器可以抑制模型失配导致的不良影响，使得ＩＭＣ系统的鲁棒性更加有保证。本文列举一个工业过程控制例     

高温除尘技术综述

介绍了高温除尘技术的特点,综述了国内外高温除尘设备的现状、水平以及发展趋势,并对该技术在各行业中的应用前景进行了展望。     

Influence of digital audio filters on image reconstruction in MRI

This paper deals with the influence of the transient response and group delay of digital filters on the MRI signal and its aspects in image reconstruction. The consequence of digital filtration on the acquired signal will be shown in the time domain (κ-space) for three basic imaging methods-echo scan, radial scan and spiral scan. The influence of the group delay and transient response of filters will be explained and a method will be proposed which compensates both these phenomena while retaining all the advantages of digital filtration. The proposed method is based on applying the principle of signal superposition and on using the consequences of the sampling principle. The method works in the time domain. It is very simple and rapid and does not depend on the properties of the acquired signal or reconstruction algorithm. It will be shown and explained in which cases the transient response can be neglected and in which it has to be compensated. In the end, the results of the proposed methods will be shown for mentioned cases on a simulated signal in the image domain. © 1998 Elsevier Science B.V. All rights reserved.     

The Analysis of the Parameters and the Functions of Rectangular Waveguide E-plane Filter

In this paper, to analyze the discontinuity structure of E-plane metal insert by mode matching method, and metal insert thickness and resonator length impact on filter design. This work was supported by the Natural Science Foundation of Jiangsu Province of China under Grant No. BK2008357.     

Filter approach to the stochastic analysis of MDOF wind-excited structures

In this paper, an approach useful for stochastic analysis of the Gaussian and non-Gaussian behavior of the response of multi-degree-of-freedom (MDOF) wind-excited structures is presented. This approach is based on a particular model of the multivariate stochastic wind field based upon a particular diagonalization of the power spectral density (PSD) matrix of the fluctuating part of wind velocity. This diagonalization is performed in the space of eigenvectors and eigenvalues that are called here wind-eigenvalues and wind-eigenvectors, respectively. From the examination of these quantities it can be recognized that the wind-eigenvectors change slowly with frequency while the first wind-eigenvalue dominates all the others in the low-frequency range. It is shown that the wind field can be modeled in a satisfactory way by taking the first wind-eigenvector as constant and by retaining only the first eigenvalue in the calculations. The described model is then used for stochastic analysis in the time domain of MDOF wind-excited structures. This is accomplished by modeling each element of the diagonalized wind-PSD matrix as the velocity PSD function of a set of second-order digital filters with viscous damping driven by white noise of selected intensity. This approach makes it easy to obtain in closed form the statistical moments of every order of the structural response, taking full advantage of the Itô calculus. Moreover, in the proposed approach, it is possible to reduce the computational effort by appropriately selecting the number of wind modes retained in the calculation.     

A new method for analysis and design of iterative learning control algorithms in the time-domain

In this paper, a novel analysis method for iterative learning control (ILC) algorithms is presented. Even though expressed in the lifted system representation and hence in the time-domain, the convergence rate as a function of the frequency content of the error signal can be determined. Subsequently, based on the analysis method, a novel ILC algorithm (F-ILC) is proposed. The convergence rate at specific frequencies can be set directly in the design process, which allows simple tuning and a priori known convergence rates. Using the F-ILC design, it is shown how to predict the required number of iterations until convergence is achieved, depending on the reference trajectory and information on the system repeatability. Numerical examples are given and experimental results obtained on an internal combustion engine test bench are shown for validation.