Consequences for automotive relays of a 42 VDC power network invehicles

Because of the increasing demand for electrical power in automotive vehicles the car manufacturers have decided worldwide to increase the nominal voltage of the automobile power network from 14 VDC to 42 VDC. Surveying the fundamentals of arc physics the authors show why this decision requires more extensive adaptations of the respective electromechanical switches than might be expected from a change by a factor three. Means to solve the problem are discussed     

Synthesis and Characterization of Telmisartan-Derived Cell Death Modulators to Circumvent Imatinib Resistance in Chronic Myeloid Leukemia

New strategies to eradicate cancer stem cells in chronic myeloid leukemia (CML) include a combination of imatinib with peroxisome proliferator-activated receptor gamma (PPARγ) ligands. Recently, we identified the partial PPARγ agonist telmisartan as effective sensitizer of resistant K562 CML cells to imatinib treatment. Here, the importance of the heterocyclic core on the cell death-modulating effects of the telmisartan-derived lead 4′-((2-propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-carboxylic acid ( 3 b ) was investigated. Inspired by the pharmacodynamics of HYL-6d and the selective PPARγ ligand VSP-51, the benzimidazole was replaced by a carbazole or an indole core. The results indicate no correlation between PPARγ activation and sensitization of resistant CML cells to imatinib. The 2-COOH derivatives of the carbazoles or indoles achieved low activity at PPARγ, while the benzimidazoles showed 60-100 % activation. Among the 2-CO₂CH₃ derivatives, only the ester of the lead ( 2 b ) slightly activated PPARγ. Sensitizing effects were further observed for this non-cytotoxic 2 b (80 % cell death), and to a lesser extent for the lead 3 b or the 5-Br-substituted ester of the benzimidazoles ( 5 b ).     

Symplectic Simulations of Radial Diffusion of Fast Alpha Particles in the Presence of Low-Frequency Modes in Rippled Tokamaks

The symplectic Hamiltonian guiding centre code which enables efficient calculation of charged particle trajectories and diffusion coefficients has been applied to fast ion motion in magnetically perturbed tokamak plasmas. Particularly fusion born alpha particle drift motion, in constant of motion space, is examined in the presence of low mode-number neoclassical tearing mode (NTM) perturbation in a toroidally rippled tokamak. The main focus of this study is to investigate the dependence of the radial diffusion coefficient of energetic ions on the perturbation strength and on the localization of the perturbation. The resonance between bounce motion and toroidal field ripples plays a significant role in this context. The presence of NTMs results in substantial enhancement of radial diffusion coefficient for passing particles. Depending on the strength and localization of the NTM it can cause enhancement or degradation of the radial ripple diffusion coefficient of trapped particles.     

Mitigation of connector damage during disengaging DC loads using polymeric arc suppressor

Although connectors are generally not designed to disconnect electrical loads under power, in some circumstances they are mated and unmated under load. For instance, during repairs, diagnostic procedures, or when blown fuses are replaced under short circuit conditions. At dc system voltage levels significantly higher than the minimum arc voltage of metals such hot-disconnections may impact the reliability of the connection, the electrical distribution system, and automotive safety. Gassing polymers mounted onto connector terminals may reduce the damage resulting from disconnections under dc loads, and therefore enable connector designs with occasionally (forward running) arcing terminals. The authors discuss the effects of different types of gassing polymers on arc extinction and connector damage of standard automotive connectors.     

Technical bases and acquisition conditions of electron-beam computed tomography

PURPOSE: In this review the technical principle and scanner characteristics of electron beam computer tomography (EBCT) are discussed. METHODS: In contrast to conventional CT, image acquisition in EBCT is achieved without mechanically moving parts. This construction allows for short acquisition times in investigating given anatomical regions (100 ms per slice) or up to 8 levels without table movement and short interscan delays (50 ms per slice). RESULTS: Depending on the nature of the investigation, the scanner can be used in the single slice, continuous volume scanning and multi slice mode. The single slice mode is used for detection and quantification of coronary calcifications and for CT angiography of the coronary vessels. Equivalent to the spiral mode in conventional CT, continuous volume scanning may be used for routine investigation of the chest and abdomen. Functional investigations of the heart and perfusion measurement of different organs can be performed in multi slice mode. Because of the geometry of the electron beam scanner, radiation exposure for certain investigations is above the exposure with conventional CT. CONCLUSION: Future developments will focus on dose efficient radiation collimation, high resolution detector systems and artefact reducing reconstruction kernels.     

Leg ulceration with associated thrombocytosis: healing of ulceration associated with treatment of the raised platelet count

Thrombocytosis is the cause of various complications in myeloproliferative disorders. We present the case of a 54-year-old woman with chronic myelogenous leukaemia who developed large ulcers on both lower legs that were refractory to standard treatment. As concomitant thrombocytosis persisted despite treatment with hydroxyurea, the new megakaryocyte inhibitor anagrelide (Agrelin) was administered and led to normalization of the platelet count within 11 days. The leg ulcers started to heal after 2 weeks and disappeared over a period of 5 months. Our findings argue for a pathogenic role of platelets in the development of leg ulcers in patients with thrombocytosis due to a myeloproliferative disorder.     

Symplectic Simulation of Fast Alpha Particle Radial Transport in Tokamaks in the Presence of TF Ripples and a Neoclassical Tearing Mode

A Hamiltonian guiding centre drift orbit code based on a symplectic integration algorithm, which enables the efficient calculation of particle trajectories and diffusion coefficients, is applied to fast alpha particle motion in magnetically perturbed tokamak plasmas. In particular, fast ion drift motion is examined in the presence of a stationary, low mode-number MHD magnetic perturbation in a toroidally rippled tokamak with circular flux surface. The main focus of our study is to investigate the dependence of the radial diffusion coefficient of energetic ions on their energy, on the perturbation strength and the localization of the perturbation. As expected, the resonance between bounce motion and toroidal field ripples plays a significant role in this context. For an ensemble of fast ions uniformly distributed in toroidal angle but with a given poloidal starting position their radial transport coefficient takes on higher values in the neighbourhood of resonance speeds and can exhibit there local minima, i.e. it shows an M-shaped speed dependence around resonances for sufficiently strong ripple perturbations. Expectedly, the addition of a modelled low-mode number neoclassical tearing mode perturbation will modify the pure ripple resonance structure of the radial diffusion coefficient. Depending on the strength and localization of the MHD mode it can cause enhancement or degradation of the radial ripple diffusion coefficient.     

Development of silver zinc oxide for general-purpose relays

The switching behavior of silver cadmium oxide (Ag/CdO), silver tin oxide (Ag/SnO/sub 2/) and silver iron oxide (Ag/Fe/sub 2/O/sub 3/) contact materials is compared to silver zinc oxide (Ag/ZnO) materials having different amounts of additives. Endurance tests were performed in a commercial general-purpose relay, subjected to resistive, inductive and inrush current loads. Results showed the performance of Ag/ZnO to be significantly dependent on the amount of additives and their grain size. The optimum Ag/ZnO was found to be equivalent or superior to other silver metal oxides depending on the applied load. Thus a substitution of Ag/CdO by an environmentally harmless Ag/ZnO material is possible.