2,075 research outputs found
Parametric tests of a traction drive retrofitted to an automotive gas turbine
The results of a test program to retrofit a high performance fixed ratio Nasvytis Multiroller Traction Drive in place of a helical gear set to a gas turbine engine are presented. Parametric tests up to a maximum engine power turbine speed of 45,500 rpm and to a power level of 11 kW were conducted. Comparisons were made to similar drives that were parametrically tested on a back-to-back test stand. The drive showed good compatibility with the gas turbine engine. Specific fuel consumption of the engine with the traction drive speed reducer installed was comparable to the original helical gearset equipped engine
From first to the second European Stroke Prevention Study
A number of recent publications have shown that secondary prevention of cerebrovascular ischemic brain events is possible with anti-aggregating drugs. Comparison between the different studies is difficult, but the results obtained with using a combination therapy with aspirin (ASA) and dipyridamole (DP) seem to be superior to the results obtained with ASA alone. The first European Stroke Prevention Study (ESPS 1), that used 990 mg ASA and 225 mg DP a day, showed this clearly. In an attempt to minimize the side effects of a large dose ASA and possibly even to improve the efficacy, ESPS 2 was established. ESPS 2 will compare 50 mg ASA, 400 mg DP, the combination of both, and placebo.Biomedical Reviews 1993; 2: 31-35
Establishing an Equitable and Fair Admissions System for an Online Doctoral Program
The field of educational technology has seen marked growth from just a small number of distance-based doctoral programs to nearly 20 today. Creating and sustaining a quality doctoral program of any kind requires a substantial amount of work; the additional challenges of online programs both increases and changes the nature of the efforts required. Among these challenges is creating an admissions process that treats people fairly, does not create a burdensome system for applicants or those involved in the selection process, and ensures the selection of a solid foundation of high quality candidates with whom faculty can mentor, who add value to the program, and who can benefit from the program. This paper explores common admissions requirements among institutions offering a distance or hybrid doctorate in educational technology and examines the specific admissions system used by the Department of Educational Technology at Boise State University
Open Access Journals in Educational Technology: Results of a Survey of Experienced Users
As the academic publishing industry evolves, there has been an unprecedented growth of open access journals (OAJs). In educational technology alone, with an estimated 270 associated journals, nearly one-third are designated as open. Though OAJs are lauded for what their availability can contribute to social justice issues (reduction of subscription requirement barriers), some remain suspicious of the content found in them and question the legitimacy of publishing in them. In this study, we sought to discover the opinions of educational technology scholars about OAJs in their own field. We were able to learn which OAJs were deemed to be most valuable, as well as the characteristics of OAJs thought to be particularly important
Minimum construction of two-qubit quantum operations
Optimal construction of quantum operations is a fundamental problem in the
realization of quantum computation. We here introduce a newly discovered
quantum gate, B, that can implement any arbitrary two-qubit quantum operation
with minimal number of both two- and single-qubit gates. We show this by giving
an analytic circuit that implements a generic nonlocal two-qubit operation from
just two applications of the B gate. We also demonstrate that for the highly
scalable Josephson junction charge qubits, the B gate is also more easily and
quickly generated than the CNOT gate for physically feasible parameters.Comment: 4 page
Switched Control of Electron Nuclear Spin Systems
In this article, we study control of electron-nuclear spin dynamics at
magnetic field strengths where the Larmor frequency of the nucleus is
comparable to the hyperfine coupling strength. The quantization axis for the
nuclear spin differs from the static B_0 field direction and depends on the
state of the electron spin. The quantization axis can be switched by flipping
the state of electron spin, allowing for universal control on nuclear spin
states. We show that by performing a sequence of flips (each followed by a
suitable delay), we can perform any desired rotation on the nuclear spins,
which can also be conditioned on the state of the electron spin. These
operations, combined with electron spin rotations can be used to synthesize any
unitary transformation on the coupled electron-nuclear spin system. We discuss
how these methods can be used for design of experiments for transfer of
polarization from the electron to the nuclear spins
H-alpha Imaging with HST+NICMOS of An Elusive Damped Ly-alpha Cloud at z=0.6
Despite previous intensive ground-based imaging and spectroscopic campaigns
and wide-band HST imaging of the z=0.927 QSO 3C336 field, the galaxy that hosts
the damped Ly-alpha system along this line-of-sight has eluded detection. We
present a deep narrow-band H-alpha image of the field of this z=0.656 damped
Ly-alpha absorber, obtained through the F108N filter of NICMOS 1 onboard the
Hubble Space Telescope. The goal of this project was to detect any H-alpha
emission 10 times closer than previous studies to unveil the damped absorber.
We do not detect H-alpha emission between 0.05'' and 6'' (0.24 and 30
kpc) from the QSO, with a 3-sigma flux limit of
erg/s/cm^2 for an unresolved source, corresponding to a star formation rate
(SFR) of M_sun/yr. This leads to a 3-sigma upper limit of 0.15
M_sun/yr/kpc^2 on the SFR density, or a maximum SFR of 1.87 M_sun/yr assuming a
disk of 4 kpc in diameter. This result adds to the number of low redshift
damped Ly-alpha absorbers that are not associated with the central regions of
Milky-Way-like disks. Damped Ly-alpha absorption can arise from high density
concentrations in a variety of galactic environments including some that,
despite their high local HI densities, are not conducive to widespread star
formation.Comment: 18 pages, 3 figures. Replaced to match published version in ApJ, 550,
585 (Apr 1 2001
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