Efficient Parallelization of Polyphase Arbitrary Resampling FIR Filters for High-Speed Applications

This article describes a method for increasing the sampling rate of efficient polyphase arbitrary resampling FIR filters. An FPGA proof of concept prototype of this architecture has been implemented in a Xilinx Kintex-7 FPGA which is able to convert the sampling rate of a signal from 500 MHz to 600 MHz. This article compares this new architecture with other best known efficient resampling architectures implemented on the same FPGA. The area usage on the FPGA shows that our proposed implementation is very proficient in high bandwidth applications without requiring significantly more resources on the FPGA. A theoretical calculation of the resampling error introduced on a modulated data stream is provided to evaluate the new architecture against other existing resampling architectures.     

Safety and Environmental Activities for ITER

This paper will summarize highlights of the safety approach and discuss the ITER EDA safety activities. The ITER safety approach is driven by three major objectives: (1) Enhancement or improvement of fusion's intrinsic safety characteristics to the maximum extent feasible, which includes a minimization of the dependence on dedicated safety systems; (2) Selection of conservative design parameters and development of a robust design to accommodate uncertainties in plasma physics as well as the lack of operational experience and data; and (3) Integration of engineered mitigation systems to enhance the safety assurance against potentially hazardous inventories in the device by deploying well-established nuclear safety approaches and methodologies tailored as appropriate for ITER.     

截面分析法对界面过渡区厚度的放大作用

在采用截面法分析研究截面过渡区厚度时，由于截平面并不一定正好垂直于集料的表面，导致得到的表观界面过渡区厚度与实际界面过渡区厚度是不同的。以3种规则形状(球形、椭圆形截面以及矩形截面)的集料为例，从几何概率角度研究了截面分析法对界面过渡区厚度的放大问题。研究结果表明，截面分析法得到的表观界面过渡区厚度都大于实际的界面过渡区厚度，平均放大倍数与集料的粒形有关。对正方体性集料而言，平均表观界面过渡区的厚度是实际界面厚度的1．12倍；对球形集料而言，实际界面过渡区厚度被放大了π／2倍。     

Local porosity analysis of pore structure in cement paste

Three-dimensional (3-D) local porosity theory (LPT) was originally proposed by Hilfer and recently used for the analysis of pore space geometry in model sandstone. LPT pursues to define the probability density functions of porosity and porosity connectivity. In doing so, heterogeneity differences in various sandstone samples were assessed. However, fundamental issues as to the stochastic concept of geometric heterogeneity are ignored in Hilfer's LPT theory. This paper focuses on proper sampling procedures that should be based on stochastic approaches to multistage sampling and geometric heterogeneity. Standard LPT analysis provides a 3-D microscopic modeling approach to materials. Traditional experimental techniques yield two-dimensional (2-D) section images, however. Therefore, this paper replaces the method for assessing material data in standard LPT theory to a more practical one, based on stereological, 3-D interpretation of quantitative image analysis data. The developed methodology is used to characterize the pore structure in hardened cement paste with various water/cement ratios (w/c) at different hydration stages.     

Countercurrent plug flow mass exchange with internal particle diffusion

The model for countercurrent steady state mass transfer between uniform dispersed phase particles and a continuous phase, both assumed to move in plug flow, with diffusion resistance inside the particles, and film resistance around the particles, is solved analytically for three particle geometries: infinite plates, infinite cylinders and spheres. In the solution, the direct relation between the local continuous phase concentration, and the average dispersed phase concentration is accounted for in the boundary condition. Concentration profiles in the mass exchanger are derived from the analytical solution, as well as asymptotic Sherwood numbers. The analytical solution requires the determination of roots of the characteristic equations, which is cumbersome for spherical particles. Correlations are provided for the asymptotic Sherwood numbers for easy computation. The model can easily be used for the analogous direct heat exchange problem.     

Barriers in spatial interactions and communications

Barriers are defined as discontinuities in the broadly defined marginal costs of communication, usually leading to a discontinuity in interaction. This paper addresses conceptual issues about barriers to communication. Several typologies of barriers are given. For example, according to the degree of permeability, barriers may discourage interaction, or may even be entirely impermeable, but examples may also be given of barriers which stimulate communication in one or both directions. Another typology of barriers addresses reasons of existence, including natural barriers, barriers created for protection purposes, barriers created for reasons of convenience, etc. The paper concludes with a number of suggestions for further research on communication barriers.     

Sulfide-iron interactions in domestic wastewater from a gravity sewer

Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4mgFeL(-1) and 0-5.1mgSL(-1), respectively. During anaerobic conditions, iron reduction kinetics were investigated and reduction rates amounted on average to 1.32mgFeL(-1)d(-1). Despite the very low solubility of iron sulfide, the reduced iron reacted only partly with sulfide to produce iron sulfide, even when dissolved sulfide was in excess. When a ferric chloride solution was added to sulfide containing anaerobic wastewater, the ferric iron was quickly reduced to ferrous forms by oxidation of dissolved sulfide and the ferrous iron precipitated almost completely as iron sulfide. During aerobic conditions, iron sulfide was oxidized with a half-life period of 11.7h. The oxidation rate of iron sulfide was significantly lower than that reported for the oxidation of dissolved sulfide.     

Endogenising demand for information in road transport

In this paper, the impact of endogenous information provision to drivers in road transport is investigated. A static economic equilibrium model is used, which allows potential road users to buy information on the prevailing (stochastic) traffic situation. It takes for granted that an individual will try to acquire proper information when the private benefits of doing so exceed the private costs. By using an information model for road users, the interesting result is found that the provision of endogenous information leads to a strict Pareto improvement. Furthermore, the model shows that — depending on the price of information — it can be efficiency improving to subsidise or tax the motorist information to the user. Finally, there is a relationship between fine congestion pricing and subsidising motorist information. It turns out that the social welfare maximising subsidy under first-best congestion pricing is equal to zero. However, subsidising information may be an attractive policy instrument when a flat congestion pricing scheme is preferred.Participates in the VSB-fonds sponsored research project Transport and Environment