11,255 research outputs found
Profile of a cell test database and a corresponding reliability database
The development of computerized control, and data retrieval for aerospace cell testing affords an excellent opportunity to incorporate three specific concepts to both manage the test area and to track product performance on a real-time basis. The adoption and incorporation of precepts fostered by this total quality management (TQM) initiative are critical to us for retaining control of our business while substantially reducing the separate quality control inspection activity. Test discrepancies are all 'equally bad' in cell acceptance testing because, for example, we presently do not discriminate between 1 or 25 mV for an overvoltage condition. We must take leadership in classifying such discrepancies in order to expedite their clearance and redirect our resources for prevention activities. The development and use of engineering alerts (or guardbanding) which more closely match our product capabilities and are toleranced tighter than the required customer specification are paramount to managing the test unit in order to remain both quality and cost effective
Sedimentology of Triassic Rocks in the Lower Connecticut Valley
Guidebook for field trips in Connecticut: New England Intercollegiate Geological Conference 60th annual meeting, Yale University, New Haven, Connecticut, October 25-27, 1968: Trip C-
Behavioral Differences Between Two Recently Sympatric Paper Wasps, the Native \u3ci\u3ePolistes Fuscatus\u3c/i\u3e and the Invasive \u3ci\u3ePolistes Dominulus\u3c/i\u3e
Polistes dominulus (Christ), an old world paper wasp, was introduced into the eastern United States in the 1970s and has been rapidly spreading westward. Recently, it has displaced the native Polistes fuscatus (F.) in at least some areas of Michigan. In order to understand why P. dominulus has been so successful, several behavioral attributes were compared between P. dominulus and P. fuscatus at a Michigan field site that contained colonies of both species nest- ing semi-naturally in plywood nestboxes.
Preworker colonies of P. dominulus had a significantly greater tendency to store nectar (and had significantly higher proportions of cells with nectar) than preworker colonies of P. fuscatus. This finding may explain the higher survivorship of P. dominulus foundresses reported in a previous study. P. dominulus also had a significantly greater tendency to build vertical nests and had significantly more pedicels per comb and per cell than P. fuscatus. These findings suggest that compared to P. fuscatus, P. dominulus may have more flexibility in the positioning of its combs and, because of a possibly stronger attachment of the comb to a substrate, may be less susceptible to bird predation. The higher winter survivorship reported for P. fuscatus over P. dominulus in a previous study does not appear to be due to differences in the proportions of gynes stranded on their nests late in the fall. Finally, behavioral evidence from videography was consistent with previous reports that P. dominulus is not replacing P. fuscatus through direct agonistic interactions
Formation of AlCuFe quasicrystalline thin films by solid state diffusion
Journal ArticleWe show that thin films 3000 A in thickness of the icosahedral AlCuFe phase can be formed by solid state diffusion of sputtered Al, Cu, and Fe layers. As for bulk materials, we propose that the icosahedral phase grows by diffusion of the 0.1 in the A13Fe layer previously formed by interdiffusion of the Al and Fe layers. These films present high resistivity values comparable to those obtained in bulk samples of high structural quality
Observation of a narrow pseudogap near the Fermi level of AlCuFe quasicrystalline thin films
Journal ArticleWe present the first experimental determination by tunneling spectroscopy of the density of states (DOS) close to the Fermi energy of AlCuFe quasicrystalline thin film samples. The measurements show that the Fermi level in a quasicrystal lies in a deep narrow pseudogap 60 m e V wide. Above an applied voltage of 50 m V a Vl / 2 contribution to the DOS is observed in agreement with electron-electron interaction effects
Scattering times and mean free path in AlCuFe quasicrystalline thin films
Journal ArticleWe present magnetoresistivity measurements on AlCuFe quasicrystalline thin films from which the temperature dependence of the inelastic scattering time (ri e) has been deduced down to 200 mK in the low field limit. We show that ri e presents a weak temperature dependence below 4 K (1/ гie ~ T°-87) which is in close agreement with the theory of Isawa predicting a crossover from a T3/2 to a T regime. Saturation effects as well as a possible shift in dimensionality have also been investigated
Does the quasicrystal AlCuFe follow Ohm's law?
Journal ArticleWe present the first measurements of the electrical I-V characteristics of AlCuFe quasicrystalline thin films processed by solid state interdiffusion of magnetron sputtered Al, Cu, and Fe layers. Despite the peculiar electronic properties of quasicrystals, our results show that those samples follow perfectly Ohm's law for bias voltages which vary by 7 orders of magnitude
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