3,722 research outputs found
The design concept of the 6-degree-of-freedom hydraulic shaker at ESTEC
The European Space Agency (ESA) has decided to extend its test facilities at the European Space and Technology Center (ESTEC) at Noordwijk, The Netherlands, by implementing a 6-degree-of-freedom hydraulic shaker. This shaker will permit vibration testing of large payloads in the frequency range from 0.1 Hz to 100 Hz. Conventional single axis sine and random vibration modes can be applied without the need for a configuration change of the test set-up for vertical and lateral excitations. Transients occurring during launch and/or landing of space vehicles can be accurately simulated in 6-degrees-of-freedom. The performance requirements of the shaker are outlined and the results of the various trade-offs, which are investigated during the initial phase of the design and engineering program are provided. Finally, the resulting baseline concept and the anticipated implementation plan of the new test facility are presented
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VPI Processes and Resin Evaluations for CPA Electrical Windings
High energy density requirements for fieldable electric gun applications has led to the air-core compensated pulsed alternator (CPA) or compulsator as the generator of choice to provide pulse power. The air-core nature of the machines combined with ambitious power density requirements has led to the minimizing of metallic supporting structures which places additional structural requirements on the electrical windings within the generators.Center for Electromechanic
Geometric dependence of Nb-BiTe-Nb topological Josephson junction transport parameters
Superconductor-topological insulator-superconductor Josephson junctions have
been fabricated in order to study the width dependence of the critical current,
normal state resistance and flux periodicity of the critical current modulation
in an external field. Previous literature reports suggest anomalous scaling in
topological junctions due to the presence of Majorana bound states. However,
for most realised devices, one would expect that trivial -periodic
Andreev levels dominate transport. We also observe anomalous scaling behaviour
of junction parameters, but the scaling can be well explained by mere geometric
effects, such as the parallel bulk conductivity shunt and flux focusing
Superconducting Mg-B films by pulsed laser deposition in an in-situ two-step process using multi-component targets
Superconducting thin films have been prepared in a two-step in-situ process,
using the Mg-B plasma generated by pulsed laser ablation. The target was
composed of a mixture of Mg and MgB2 powders to compensate for the volatility
of Mg and therefore to ensure a high Mg content in the film. The films were
deposited at temperatures ranging from room temperature to 300 degrees C
followed by a low-pressure in-situ annealing procedure. Various substrates have
been used and diverse ways to increase the Mg content into the film were
applied. The films show a sharp transition in the resistance and have a zero
resistance transition temperature of 22-24 K.Comment: 4 pages, 3 figures, submitted to Applied Physics Letter
Generalization of Gutzwiller Approximation
We derive expressions required in generalizing the Gutzwiller approximation
to models comprising arbitrarily degenerate localized orbitals.Comment: 6 pages, 1 figure, to appear in J.Phys.Soc.Jpn. vol.6
Traps for the Unwary: Why Counsel Should Think Twice Before Joining Additional Parties in Civil Litigation
One of the first important strategy decisions that defense counsel across the Commonwealth often face at the outset of a civil case is whether to join a third party as an additional defendant. Many counsel make the decision quickly, with only minimal information, in an attempt to shift to the joined party all of the liability for the plaintiffs claim. Because of the Pennsylvania courts\u27 interpretation of the joinder rules, however, a defendant\u27s decision to join a third party, although well intentioned, may create explosive, adverse consequences at trial. This article critically examines the courts\u27 interpretation of the joinder rules and proposes amendments to the Pennsylvania Rules of Civil Procedure to restore balance between the interests of plaintiffs and defendants
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