过滤机技术经济分析

本文分析了国内外几种典型过滤机的投资和运行成本，结果发现，国内真空过滤机投资最小，但单位精矿过滤成本并不低；陶瓷过滤机投资大，但单位精矿过滤成本较低；国外产的压滤机投资较大，单位精矿过滤成本也较大。     

Characterization of best Chebychev approximation using the frequency response of IIR digital filters with convex stability

This paper deals with the application of Chebychevʼs approximation theory to IIR digital filter frequency response (FR) approximation. It explores the properties of the frequency response of IIR digital filters as a nonlinear complex approximating function; IIR digital filter frequency response is used to approximate a prescribed magnitude and phase responses. The approximation problem is closely related to optimization. If the set of approximating functions is non-convex, the optimization problem is difficult and may converge to a local minimum. The main results presented in the paper are proposing a convex stability domain by introducing a condition termed “sign condition” and characterization of the best approximation by the Global Kolmogorovʼs Criterion (GKC). The Global Kolmogorovʼs Criteria is shown to be also a necessary condition for the approximation problem. Finally, it is proved that the best approximation is a global minimum. The sign condition can be incorporated as a constraint in an optimization algorithm.     

基于PMF-FFT的伪码捕获算法分析

建立了PMF-FFT算法的数学模型,分析了相关器个数、相关积累长度和FFT点数对积累损失、扇贝损失和频率分辨率的影响。在此基础上,结合算法的效率和运算量,给出了PMF-FFT算法参数选择的原则和依据。     

Slug Test Analysis in Vertical Cutoff Walls with Consideration of Filter Cake

In constructing a vertical cutoff wall, bentonite-water slurry is frequently used to maintain the stability of sidewalls during excavation before backfilling the trench with less permeable materials to complete the cutoff wall construction. This procedure leads to a thin but relatively impermeable layer, called a filter cake, on the excavation surface. The aim of this paper is to examine the effect of a filter cake on evaluating hydraulic conductivity of the cutoff wall backfill through a slug test analysis with the aid of the verified numerical program, Slug_3D. As an upper bound solution for evaluation of the hydraulic conductivity of the cutoff wall backfill, no-flux boundary conditions for the boundaries of cutoff walls are imposed to consider the effect of filter cakes. The type-curve method and modified line-fitting method are employed to reanalyze the case of EMCON/OWT, Inc., as an example. The previous analysis, without consideration of a filter cake, is compared with the current results that consider the filter cake to reveal the necessity of considering the effect of a filter cake in the slug test analysis. The comparison shows that the hydraulic conductivity of the cutoff wall backfill will be underestimated in a slug test analysis if the filter cake is not properly considered.     

Limitations to the Use of Woven Roving Glass Fibers in Plastic Composites,or the Case Against Woven Roving

Composite materials consist of at least two chemically distinct phases basically having a reinforcing material supported in a matrix material with a distinct reinforcement/matrix (R/M) interface separating the components; the components must be combined three-dimensionally. The composite has properties distinctly different from the properties of any constituents, which generally would not be achieved in any of the constituents acting alone. The principle is to use the plastic flow in the matrix to load the reinforcement in the direction of the applied load. To do this it is necessary to transfer and share the externally applied service loads of the composite through the weak matrix to the stronger reinforcement by a shear loading action. The job of the matrix is to transmit and distribute the stresses onto the individual fibers and to maintain the separation and orientation of the fibers. The interface is the critical factor that determines to what extent the potential properties of the composite will be achieved and maintained during usage. The interface must have the appropriate chemical and physical features in order to provide the necessary load transfer from the matrix to the reinforcement [1]. While the strain at the point of service loading is not uniformly distributed over the composite cross section, a finite distance away it does assume a uniform distribution. At this area the shear stress at the component interfaces is zero in the direction of the applied load [2].     

Thinking about Antarctic Heritage: Kaleidoscopes and filters

The preliminary results of a project that is currently investigating the nature and range of meanings of Antarctic heritage are explored. The project involves two visits to Scott Base, and the subjects of the qualitative research are the members of the New Zealand Antarctic community. Work so far suggests that different meanings do exist, and a four-fold typology of meanings is suggested which needs to be considered in decisions affecting the future of Antarctica.     

用离散颗粒数值模拟对陶瓷过滤器滤饼结构的研究

针对IGCC和PFBC中的关键问题 ,用离散颗粒数值模拟方法对高温陶瓷过滤器滤饼的形成过程进行了数值模拟。通过对模拟结果的分析 ,得出了滤饼的内部结构特性。研究发现 ,同种粉尘颗粒在滤饼内部的分布具有显著的不均匀性。在滤饼形成过程中 ,小粉尘颗粒明显有向滤饼内部渗透的现象     

State Estimation in Structural Systems with Model Uncertainties

This paper presents an observer designed under the assumption that differences between predicted and measured outputs arise from discrepancies between the real structural system and the nominal model used to represent it. The observer gain is independent of the assumed model error parametrization and proves to be the transpose of the state to output matrix of a state space formulation. The estimated state with the proposed observer is shown to be identical to that obtained by exciting the nominal model with the known input while adjusting the measured portion of the state to match the measurements at the start of every step. Numerical experiments suggest that the proposed observer can provide state estimates that are substantially more accurate than results predicted by projecting the measurements in a truncated modal space.     

Ozone Treatment of Small–Size Swimming Pools and Whirlpools

Current pool water treatment system designs tend to ignore the relationships between rates of disinfection of microorganisms present and performances of the filters. In this paper, the two subjects will be discussed, with relationship to small swimming pools and whirlpools (spas), emphasizing the problems arising when operating at different system volumes. The effects of proper and improper disinfection upon the operating characteristics and performances of pool and whirlpool water filters will be presented. Furthermore, conditions reducing the trihalomethane concentrations are compared. The role of ozone in overcoming current problems in these two areas will be discussed, in particular, the recent use of compact high frequency ozone generators is examined.