362 research outputs found
Self-discharge characteristics of spacecraft nickel-cadmium cells at elevated temperatures
The effects of heat generation were determined in NiCd cells during high temperature storage on open circuits. The testing was designed to determine the extent to which thermal stability is a valid concern, at temperature of exposure (externally effected) between 40 and 120 C
Nickel hydrogen low Earth orbit test program update and status
The current status of nickel-hydrogen (NiH2) testing ongong at NWSC, Crane In, and The Aerospace Corporation, El Segundo, Ca are described. The objective of this testing is to develop a database for NiH2 battery use in Low Earth Orbit (LEO) and support applications in Medium Altitude Orbit (MAO). Individual pressure vessel-type cells are being tested. A minimum of 200 cells (3.5 in diameter and 4.5 in diameter) are included in the test, from four U.S. vendors. As of this date (Nov. 18, 1986) approximately 60 cells have completed preliminary testing (acceptance, characterization, and environmental testing) and have gone into life cycling
Navigating the Winds of Change: Licensing, Registration, and Regulatory Overlay for Wind Farms and Associated Transmission in Texas
The State of Texas leads the United States in wind energy generation capacity—it has more than twice the wind generation capacity of the next-closest state, California. If Texas was an independent nation, it would rank sixth in the world in total installed wind capacity. Texas has a rich history of legislation and regulatory effort to thank for these statistics, which reflects the knowledge that energy and infrastructure drive the economy. Starting in 1999, Texas became one of the first states to enact a Renewable Portfolio Standard (“RPS”). The RPS set a state-wide goal for new renewable energy installation with deadlines for when that goal was to be met. In addition to passing an RPS, Texas also created Competitive Renewable Energy Zones (“CREZs”). CREZs are areas of Texas that have been designated by the Public Utility Commission of Texas (“PUCT”) to receive special benefits for wind transmission and development due to their strong wind resources and large financial commitments in the region by wind developers. These programs, and several others, have helped the wind industry in Texas grow exponentially to continually reach the goals set out by the RPS long before deadlines arrive. In fact, on a recent day towards the end of March, wind generation accounted for 29% of the electricity used by most Texans
Relationships between Peak Oxygen Uptake and Arterial Function: a Preliminary Study
Please view abstract in the attached PDF file
Electronic energy relaxation and transition frequency jumps of single molecules at 30 mK
Transition frequency jumps for single terrylene molecules in a polyethylene matrix caused by resonant laser irradiation are investigated at 30 mK. These jumps are not accompanied by substantial sample heating. A model for the effect is: proposed, based on the interaction of tunneling two-level systems (TLSs) surrounding the single molecule with high-energy nonthermal phonons emitted by the molecule during electronic energy relaxation. The radius of the effective interaction volume is estimated to be r(m) approximate to 12.5 nm, and the interaction cross section for nonequilibrium phonon -TLS scattering is estimated as similar to 10(-22) cm(-2)
A microscopic quantum dynamics approach to the dilute condensed Bose gas
We derive quantum evolution equations for the dynamics of dilute condensed
Bose gases. The approach contains, at different orders of approximation, for
cases close to equilibrium, the Gross Pitaevskii equation and the first order
Hartree Fock Bogoliubov theory. The proposed approach is also suited for the
description of the dynamics of condensed gases which are far away from
equilibrium. As an example the scattering of two Bose condensates is discussed.Comment: 8 pages, submitted to Phys. Rev.
Microscopic Dynamics in a Strongly Interacting Bose-Einstein Condensate
An initially stable 85Rb Bose-Einstein condensate (BEC) was subjected to a
carefully controlled magnetic field pulse in the vicinity of a Feshbach
resonance. This pulse probed the strongly interacting regime for the
condensate, with calculated values for the diluteness parameter (na^3) ranging
from 0.01 to 0.5. The field pulse was observed to cause loss of atoms from the
condensate on remarkably short time scales (>=10 microsec). The dependence of
this loss on magnetic field pulse shape and amplitude was measured. For
triangular pulses shorter than 1 ms, decreasing the pulse length actually
increased the loss, until extremely short time scales (a few tens of
microseconds) were reached. Such time scales and dependencies are very
different from those expected in traditional condensate inelastic loss
processes, suggesting the presence of new microscopic BEC physics.Comment: 4 pages in latex2E, 4 eps figures; revised Fig.1, revised
scatt.lengths, added discussion, new refs., resubmitted to PR
Low Resolution Spectral Templates For AGNs and Galaxies From 0.03 -- 30 microns
We present a set of low resolution empirical SED templates for AGNs and
galaxies in the wavelength range from 0.03 to 30 microns based on the
multi-wavelength photometric observations of the NOAO Deep-Wide Field Survey
Bootes field and the spectroscopic observations of the AGN and Galaxy Evolution
Survey. Our training sample is comprised of 14448 galaxies in the redshift
range 0<~z<~1 and 5347 likely AGNs in the range 0<~z<~5.58. We use our
templates to determine photometric redshifts for galaxies and AGNs. While they
are relatively accurate for galaxies, their accuracies for AGNs are a strong
function of the luminosity ratio between the AGN and galaxy components.
Somewhat surprisingly, the relative luminosities of the AGN and its host are
well determined even when the photometric redshift is significantly in error.
We also use our templates to study the mid-IR AGN selection criteria developed
by Stern et al.(2005) and Lacy et al.(2004). We find that the Stern et
al.(2005) criteria suffers from significant incompleteness when there is a
strong host galaxy component and at z =~ 4.5, when the broad Halpha emission
line is redshifted into the [3.6] band, but that it is little contaminated by
low and intermediate redshift galaxies. The Lacy et al.(2004) criterion is not
affected by incompleteness at z =~ 4.5 and is somewhat less affected by strong
galaxy host components, but is heavily contaminated by low redshift star
forming galaxies. Finally, we use our templates to predict the color-color
distribution of sources in the upcoming WISE mission and define a color
criterion to select AGNs analogous to those developed for IRAC photometry. We
estimate that in between 640,000 and 1,700,000 AGNs will be identified by these
criteria, but will have serious completeness problems for z >~ 3.4.Comment: Accepted for publication in The Astrophysical Journal. 26 text pages
+ 3 tables + 20 figures, modified to include comments made by the referee.
Fortran codes, templates and electronic tables available at
http://www.astronomy.ohio-state.edu/~rjassef/lrt
Early Universe Quantum Processes in BEC Collapse Experiments
We show that in the collapse of a Bose-Einstein condensate (BEC) {For an
excellent introduction to BEC theory, see C. Pethick and H. Smith,
Bose-Einstein condensation in dilute gases (Cambridge University Press,
Cambridge, England, 2002)} certain processes involved and mechanisms at work
share a common origin with corresponding quantum field processes in the early
universe such as particle creation, structure formation and spinodal
instability. Phenomena associated with the controlled BEC collapse observed in
the experiment of Donley et al E. Donley et. al., Nature 412, 295 (2001)(they
call it `Bose-Nova', see also J. Chin, J. Vogels and W. Ketterle, Phys. Rev.
Lett. 90, 160405 (2003)) such as the appearance of bursts and jets can be
explained as a consequence of the squeezing and amplification of quantum
fluctuations above the condensate by the dynamics of the condensate. Using the
physical insight gained in depicting these cosmological processes, our analysis
of the changing amplitude and particle contents of quantum excitations in these
BEC dynamics provides excellent quantitative fits with the experimental data on
the scaling behavior of the collapse time and the amount of particles emitted
in the jets. Because of the coherence properties of BEC and the high degree of
control and measurement precision in atomic and optical systems, we see great
potential in the design of tabletop experiments for testing out general ideas
and specific (quantum field) processes in the early universe, thus opening up
the possibility for implementing `laboratory cosmology'.Comment: 7 pages, 3 figures. Invited Talk presented at the Peyresq Meetings of
Gravitation and Cosmology, 200
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