Fabrication of microfluidic networks with integrated electrodes

In this paper a method is presented for the fabrication of micro-channel networks in glass with integrated and insulated gate electrodes to control the zeta-potential at the insulator surface and therewith the electro-osmotic flow (EOF). The fabrication of the electrodes is a sequence of photolithography, etching and thin film deposition steps on a glass substrate, followed by chemical mechanical polishing (CMP) and subsequently direct thermal bonding to a second glass plate to form closed micro-channels. Plasma enhanced chemical vapor deposition (PECVD) SiO₂-layers as insulating material between the electrodes and micro-channels and different electrode materials are examined with respect to a high bonding temperature to obtain an optimal insulating result. A CMP process for the reduction of the SiO₂ topography and roughness is studied and optimized in order to obtain a surface that is smooth enough to be directly bondable to a second glass plate.     

A constructive approach to calculate parameter ranges for systems of geometric constraints

Geometric constraints are at the heart of parametric and feature-based CAD systems. Changing values of geometric constraint parameters is one of the most common operations in such systems. However, because allowable parameter values are not known to the user beforehand, this is often a trial-and-error process. We present an approach for automatically determining the allowable range for parameters of geometric constraints. Considered are systems of distance and angle constraints on points in 3D that can be decomposed into triangular and tetrahedral subproblems, by which most practical situations in parametric and feature-based CAD systems can be represented. Our method uses the decomposition to find critical parameter values for which subproblems degenerate. By solving one problem instance for each interval between two subsequent critical values, the exact parameter range is determined for which a solution exists.     

Discrete port-Hamiltonian systems

Either from a control theoretic viewpoint or from an analysis viewpoint it is necessary to convert smooth systems to discrete systems, which can then be implemented on computers for numerical simulations. Discrete models can be obtained either by discretizing a smooth model, or by directly modeling at the discrete level itself. One of the goals of this paper is to model port-Hamiltonian systems at the discrete level. We also show that the dynamics of the discrete models we obtain exactly correspond to the dynamics obtained via a usual discretization procedure. In this sense we offer an alternative to the usual procedure of modeling (at the smooth level) and discretization.     

Polymer‐based transistors used as pixel switches in active‐matrix displays

A 2‐in. active‐matrix display was demonstrated, containing 4096 solution‐processed polymer‐based transistors. By using the polymer‐dispersed liquid‐crystal display (LCD) effect, this results in a reflective, low‐power display with paper‐like contrast. The influence of the transistor parameters on the display performance is analyzed by use of a model for charging and discharging of the pixel capacitors. Good agreement was obtained between the model and the experimental data. Scaling behavior allows estimation of the performance required for transistors in a quarter‐VGA display. These requirements are met by solution‐processed pentacene transistors.     

Optimal control of a hybrid power compensator using an artificialneural network controller

A hybrid power compensator (HPC) consisting of a static VAr compensator and a dynamic compensator needs to be optimally controlled during the compensation of nonlinear loads. The HPC must be controlled to meet minimum requirements in terms of power factor and harmonic distortion, while at the same time minimizing its total cost. The use of an artificial neural network (ANN) to control the HPC amid a very dynamic environment to achieve the above is investigated. A state-space model of the power distribution network together with the HPC forms the basis of evaluation of the mentioned controller. The model was calibrated against actual in-network measurements. The results obtained reveals that the application of an ANN in controlling an HPC is feasible given that the ANN parameters are chosen appropriately     

Adding Value to Data

Today's rapidly changing, global, competitive business environment requires that an enterprise optimize its operations and leverage its data, information, and knowledge resources better than ever before. the result is an ever-increasing demand for data, information, and knowledge about the enterprise, its operations, and about its customers, suppliers, and business partners. the database management system is the key component of the information systems infrastructure of the modern enterprise that is focused on meeting this demand. the database management system is an organized store of the enterprise' data that provides ever-increasing capabilities for adding value to data by turning data into information; by turning this information into knowledge; and by sharing data, information, and knowledge securely throughout the enterprise.     

Term Rewriting with Type-safe Traversal Functions

Term rewriting is an appealing technique for performing program analysis and program transformation. Tree (term) traversal is frequently used but is not supported by standard term rewriting. In this paper, many-sorted first-order term rewriting is extended with automatic tree traversal by adding two primitive tree traversal strategies and complementing them with three types of traversals. These so-called traversal functions can be either top-down or bottom-up. They can be sort preserving, mapping to a single sort, or a combination of these two. Traversal functions have a simple design, their application is type-safe in a first-order many-sorted setting and can be implemented efficiently. We describe the operational semantics of traversal functions and discuss applications.     

High-pressure pulse radiolysis as a tool in the study of transition metal reaction mechanisms

The unique combination of high-pressure and pulse radiolysis kinetic techniques enables detailed mechanistic insight for a large variety of chemical processes to be gained. Typical examples for transition metal reactions are presented. These include ligand substitution, electron transfer, reactions of complexes with uncommon oxidation states, and reactions with radicals, including the formation and decomposition reactions of complexes with metal-carbon sigma bonds. The volumes of activation and volume profiles obtained form the basis of a critical analysis of different plausible reaction mechanisms.     

PSpice simulation of ultrasonic systems

The usage of electrical analogies for the simulation of wave generation and propagation in ultrasound transducers is well established. In this paper a PSpice approach that includes the temperature and frequency dependency of the transducer performance is proposed. The analogy between acoustic wave propagation and wave propagation in an electric transmission line is given. Further ways to deduce temperature and frequency dependencies are discussed. The simulation approach is applied to a pulse-echo setup for the determination of speed of sound and attenuation in liquids and solids. Experiments and simulations are made for three temperatures and in the frequency range 1-12 MHz using water, glycerine, and polymers (PMMA and PEEK) as test samples. Comparison shows a good agreement between simulation and experiments. Results for glycerine indicates that the available attenuation models for high viscosity liquids is inappropriate.