54,272 research outputs found
Liquid switch is remotely operated by low dc voltage
A liquid switch which does not depend on any mechanical, gravitational, or inertial actuation is developed for use in space environments. It may be remotely operated on low dc voltage
Circuit controls transients in SCR inverters
Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load
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An investigation into the sources of fluctuation in real and nominal wage rates in eight EU countries: A structural VAR approach
This paper uses the SVAR approach to assess the degree of labor market flexibility –measured as the responsiveness of real and nominal wages to permanent and temporary shocks - in eight EU member states (France, Italy, UK, Netherlands, Poland, Hungary, Slovakia and the Czech Republic) with a view to assessing their suitability for Euro-area membership. It is found that for Hungary and the Czech Republic real wages are more responsive to real (permanent) shocks than some current members of the Euro zone, such as Italy. On the other hand, in Poland and Slovakia, real wage flexibility seems to be extremely low, making higher unemployment more likely than other EU countries and early euro-area membership unadvisable
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Financial liberalisation in India and a new test of the complementarity hypothesis
This paper reappraises the financial repression hypothesis for India in the light of the partial liberalisation of the financial sector in the early 1990s, using for the first time, state-of-art multivariate cointegration and vector error correction models (VECM). From this robust test we find that for the Indian economy over the sample period 1951-1999 money and capital are complementary, suggesting that higher real interest rates will raise the demand for money and lead to higher levels of investment. Furthermore, testing for a structural break in the early 1990s – to coincide with the liberalisation of the financial sector in India – suggests that these reforms have not significantly changed the complementary relationship between money and capital. The policy implication is that further financial liberalisation is required in India, to enhance investment and economic growth
An unconventional magnetically-coupled multivibrator
Multivibrator circuit provides a low-frequency sine wave output without using a low-frequency power transformer or filter components. This circuit, utilizing two transistors and a magnetic core, represents a reduction in complexity, size, and weight over similar units
Power conditioning - inversion, conversion, and regulation
Switching element requirements for spacecraft electric power conversion, inversion, and regulatio
Sound separation probe
Probe separates sound waves from turbulent flow pressure fluctuations in ducted airstreams by using principle that sound waves and turbulent flow pressure perturbations travel at different velocities
Completion of evaluation of manufacturing processes for B/Al composites containing 0.2mm diameter boron fibers
Four fabricators produced a total of 54 B/1100 Al, B/6061 Al, and B/2024 Al panels for evaluation. The 8 ply unidirectional, 45 to 50 volume percent, panels were made using 0.20 mm diameter boron fibers which were obtained from a single supplier. Hot press consolidation was carried out in vacuum except for one set of dry woven tape panels which were hot pressed in air. A single testing contractor conducted nondestructive inspection, metallography, fractography and mechanical property tests. The mechanical property tests included 21 and 260 C tensile tests and 21 C shear tests. Panel quality, as measured by nondestructive evaluation, was generally good as were the 21 C tensile properties. The panels hot pressed in air delaminated in the shear tests. Shear strength values were lower in these panels. But tensile strengths were not affected by the delaminations because of the relation between the tensile loading direction and the delaminations. Composite tensile strength was found to be proportional to the volume percent boron and the aluminum matrix rather than to the tape used or fabrication technique. Suitability of these composites for 260 C service was confirmed by tensile tests
A timeline algorithm for astronomy missions
An algorithm is presented for generating viewing timelines for orbital astronomy missions of the pointing (nonsurvey/scan) type. The algorithm establishes a target sequence from a list of candidate targets in a way which maximizes total viewing time. Two special cases are treated. One concerns dim targets which, due to lighting constraints, are scheduled only during the antipolar portion of each orbit. They normally require long observation times extending over several revolutions. A minimum slew heuristic is employed to select the sequence of dim targets. The other case deals with bright, or short duration, targets, which have less restrictive lighting constraints and are scheduled during the portion of each orbit when dim targets cannot be viewed. Since this process moves much more rapidly than the dim path, an enumeration algorithm is used to select the sequence that maximizes total viewing time
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