Surge immunity of electronic equipment

Only 7 of the sample with 20 video recorders passed the impulse test without any failure. Almost all failures observed were located in the primary part of the power supply. Typically the radio interference suppression capacitors failed and/or internal fuses were blowing. Although the damage is rather small and limited to a few components, a rather expensive repair is required in any case. Since the radio interference suppression capacitors are the weakest point in the insulation system, either their quality has to be improved or some series impedance has to be used for suppression of the transients     

An optimal and a heuristic algorithm for the single-item retrieval problem in puzzle-based storage systems with multiple escorts

Puzzle-based storage systems consist of densely stored unit loads on a square grid. The problem addressed in this paper is to retrieve a stored unit load from a puzzle-based storage using the minimum number of item moves. While previous research contributed optimal algorithms for only up to two empty locations (escorts), our approach solves configurations where multiple empty locations are arbitrarily positioned in the grid. The problem is formulated as a state space problem and solved to optimality using an exact search algorithm. To reduce the search space, we derive bounds on the number of eligible empty locations and develop several search-guiding estimate functions. Furthermore, we present a heuristic variant of the search algorithm to solve larger problem instances. We evaluate both solution algorithms on a large set of problem instances. Our computational results show that the algorithms clearly outperform existing approaches where they are applicate and solve more general configurations, which could not be solved to optimality before. The heuristic variant efficiently yields high-quality solutions for significantly larger instances of practically relevant size.     

Pulverization of Low Density Polyethylene and Rubber Under High Shear and Normal Forces

ABSTRACT

To obtain a fundamental understanding of pulverization of rubber and thermoplastic materials, such as low density polyethylene (LDPE), using our solid state shear extraction process (SSSE), a thin disk of the material was placed between two parallel plates of a Bridgeman Anvil. Normal forces of 300-2000 kg and rpm of 2-32 were exerted to obtain shear and normal forces needed for pulverization. Our experimental results showed that the residence time required for effective pulverization is a function of normal load. It was also determined that the minimum normal load required for pulverization is reduced at higher rates of rotation. Although increasing normal load was found to improve the pulverization, significant agglomeration was obtained at very high normal force. This indicates the existence of an optimum condition for obtaining fine particle size distribution. It was observed that the pulverization of both LDPE and rubber samples were initiated at the outer radial edge of the disk.

Computational analysis of the deformation of LDPE and rubber disks in a Bridgeman Anvil were performed using ANSYS computer code. Experimental stress-strain data from a simple extension of samples were used to calculate the constants for a Mooney-type stored energy function, and used as input to the computer code. Similar to our experimental results, our calculations showed much strain energy at the outer radial edge of the disk, and in turn more pulverization.     

Model-based imaging of cardiac electrical excitation in humans

Activation time (AT) imaging from electrocardiographic (ECG) mapping data has been developing for several years. By coupling ECG mapping and three-dimensional (3-D) + time anatomical data, the electrical excitation sequence can be imaged completely noninvasively in the human heart. In this paper, a bidomain theory-based surface heart model AT imaging approach was applied to single-beat data of atrial and ventricular depolarization in two patients with structurally normal hearts. In both patients, the AT map was reconstructed from sinus and paced rhythm data. Pacing sites were the apex of the right ventricle and the coronary sinus (CS) ostium. For CS pacing, the reconstructed AT pattern on the endocardium of the right atrium was compared with the CARTO map in both patients. The localization errors of the origins of the initial endocardial breakthroughs were determined to be 6 and 12 mm. The sites of early activation and the areas with late activation were estimated with sufficient accuracy. The reconstructed sinus rhythm sequence was in good qualitative agreement with the pattern previously published for the isolated Langendorff-perfused human heart.     

Unternehmensnetzwerke schützen und dennoch mobiles Potential nutzen

Dieser Beitrag m?chhte auf der einen Seite auf die Gefahr aufmerksam machen, die von mobilen Endger?ten wie Smartphones ausgeht, aber auf der anderen Seite auch von L?sungsm?glichkeiten berichten, so dass die wertvollen Unternehmensressourcen abgesichert werden k?nnen, obwohl mobile L?sungen zus?tzlich im Einsatz sind. Ziel ist es, ein ?hnliches Sicherheitsniveau erreichen zu k?nnen, wie bei vorhandenen Desktop-Arbeitspl?tzen.