2,154 research outputs found
NASA-FAA helicopter Microwave Landing System curved path flight test
An ongoing series of joint NASA/FAA helicopter Microwave Landing System (MLS) flight tests was conducted at Ames Research Center. This paper deals with tests done from the spring through the fall of 1983. This flight test investigated and developed solutions to the problem of manually flying curved-path and steep glide slope approaches into the terminal area using the MLS and flight director guidance. An MLS-equipped Bell UH-1H helicopter flown by NASA test pilots was used to develop approaches and procedures for flying these approaches. The approaches took the form of Straight-in, U-turn, and S-turn flightpaths with glide slopes of 6 deg, 9 deg, and 12 deg. These procedures were evaluated by 18 pilots from various elements of the helicopter community, flying a total of 221 hooded instrument approaches. Flying these curved path and steep glide slopes was found to be operationally acceptable with flight director guidance using the MLS
The Impact of Corporate Restructuring and Downsizing on the Managerial Careers of Minorities and Women: Lessons Learned from Nine Companies
Glass Ceiling ReportGlassCeilingBackground6ImpactofCorporateDownsizing.pdf: 1346 downloads, before Oct. 1, 2020.0-Pages_from_ImpactofCorporateRestructuringDownsizing.pdf: 87 downloads, before Oct. 1, 2020.1-Appendixfrom_ImpactofCorporateRestructuringDownsizing.pdf: 2958 downloads, before Oct. 1, 2020
Superconductivity in LnFePO (Ln = La, Pr, and Nd) single crystals
Single crystals of the compounds LaFePO, PrFePO, and NdFePO have been
prepared by means of a flux growth technique and studied by electrical
resistivity, magnetic susceptibility and specific heat measurements. We have
found that PrFePO and NdFePO display superconductivity with values of the
superconducting critical temperature T_c of 3.2 K and 3.1 K, respectively. The
effect of annealing on the properties of LaFePO, PrFePO, and NdFePO is also
reported. The LnFePO (Ln = lanthanide) compounds are isostructural with the
LnFeAsO_{1-x}F_x compounds that become superconducting with T_c values as high
as 55 K for Ln = Sm. A systematic comparison of the occurrence of
superconductivity in the series LnFePO and LnFeAsO_{1-x}F_x points to a
possible difference in the origin of the superconductivity in these two series
of compounds.Comment: submitted to the New Journal of Physic
Pressure-induced superconductivity in the giant Rashba system BiTeI
At ambient pressure, BiTeI is the first material found to exhibit a giant
Rashba splitting of the bulk electronic bands. At low pressures, BiTeI
undergoes a transition from trivial insulator to topological insulator. At
still higher pressures, two structural transitions are known to occur. We have
carried out a series of electrical resistivity and AC magnetic susceptibility
measurements on BiTeI at pressure up to ~40 GPa in an effort to characterize
the properties of the high-pressure phases. A previous calculation found that
the high-pressure orthorhombic P4/nmm structure BiTeI is a metal. We find that
this structure is superconducting with Tc values as high as 6 K. AC magnetic
susceptibility measurements support the bulk nature of the superconductivity.
Using electronic structure and phonon calculations, we compute Tc and find that
our data is consistent with phonon-mediated superconductivity.Comment: 7 pages, 7 figure
Pressure-Induced Superconductivity in Sc to 74 GPa
Using a diamond anvil cell with nearly hydrostatic helium pressure medium we
have significantly extended the superconducting phase diagram Tc(P) of Sc, the
lightest of all transition metals. We find that superconductivity is induced in
Sc under pressure, Tc increasing monotonically to 8.2 K at 74.2 GPa. The Tc(P)
dependences of the trivalent d-electron metals Sc, Y, La, and Lu are compared
and discussed within a simple s-d charge transfer framework.Comment: to be published in Phys. Rev. B (Brief Reports
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