321 research outputs found
Designing a Heat Sink for Lithium-ion Battery Packs in Electric Vehicles
This report addresses the concepts and implementation of fluid cooled heat sink designs for an electric or hybrid vehicle battery. To determine the battery’s temperature and heat flux profile, testing was performed by measuring these values at multiple locations on a lithium-ion pouch battery using heat flux sensors and thermocouples during the charge and discharge cycles of the battery. Once the data was collected and analyzed, trendlines were fit to the heat flux data then used to create equations for the heat flux profile during the discharging stage. Each equation represented a specific region on the battery geometry. Four heat sink designs were modeled in COMSOL Multiphysics to optimize cooling. The third model concept (Model 3) was chosen as the best model because it cooled the battery to the lowest temperature with the lowest pressure drop
Designing a Heat Sink for Lithium-ion Battery Packs in Electric Vehicles
This report addresses the concepts and implementation of fluid cooled heat sink designs for an electric or hybrid vehicle battery. To determine the battery’s temperature and heat flux profile, testing was performed by measuring these values at multiple locations on a lithium-ion pouch battery using heat flux sensors and thermocouples during the charge and discharge cycles of the battery. Once the data was collected and analyzed, trendlines were fit to the heat flux data then used to create equations for the heat flux profile during the discharging stage. Each equation represented a specific region on the battery geometry. Four heat sink designs were modeled in COMSOL Multiphysics to optimize cooling. The third model concept (Model 3) was chosen as the best model because it cooled the battery to the lowest temperature with the lowest pressure drop
F21RS SGR No. 5 (Memorial Day)
A Resolution
To Urge and Request LSU Faculty to not hold University classes on Memorial Da
Seeing double with K2: Testing re-inflation with two remarkably similar planets around red giant branch stars
Despite more than 20 years since the discovery of the first gas giant planet
with an anomalously large radius, the mechanism for planet inflation remains
unknown. Here, we report the discovery of EPIC228754001.01, an inflated gas
giant planet found with the NASA K2 Mission, and a revised mass for another
inflated planet, K2-97b. These planets reside on ~9 day orbits around host
stars which recently evolved into red giants. We constrain the irradiation
history of these planets using models constrained by asteroseismology and
Keck/HIRES spectroscopy and radial velocity measurements. We measure planet
radii of 1.31 +\- 0.11 Rjup and and 1.30 +\- 0.07 Rjup, respectively. These
radii are typical for planets receiving the current irradiation, but not the
former, zero age main sequence irradiation of these planets. This suggests that
the current sizes of these planets are directly correlated to their current
irradiation. Our precise constraints of the masses and radii of the stars and
planets in these systems allow us to constrain the planetary heating efficiency
of both systems as 0.03% +0.03%/-0.02%. These results are consistent with a
planet re-inflation scenario, but suggest the efficiency of planet re-inflation
may be lower than previously theorized. Finally, we discuss the agreement
within 10% of stellar masses and radii, and planet masses, radii, and orbital
periods of both systems and speculate that this may be due to selection bias in
searching for planets around evolved stars.Comment: 18 pages, 15 figures, accepted to AJ. Figures 11, 12, and 13 are the
key figures of the pape
Science from an Ultra-Deep, High-Resolution Millimeter-Wave Survey
Opening up a new window of millimeter-wave observations that span frequency
bands in the range of 30 to 500 GHz, survey half the sky, and are both an order
of magnitude deeper (about 0.5 uK-arcmin) and of higher-resolution (about 10
arcseconds) than currently funded surveys would yield an enormous gain in
understanding of both fundamental physics and astrophysics. In particular, such
a survey would allow for major advances in measuring the distribution of dark
matter and gas on small-scales, and yield needed insight on 1.) dark matter
particle properties, 2.) the evolution of gas and galaxies, 3.) new light
particle species, 4.) the epoch of inflation, and 5.) the census of bodies
orbiting in the outer Solar System.Comment: 5 pages + references; Submitted to the Astro2020 call for science
white paper
Lattice QCD and Particle Physics
Contribution from the USQCD Collaboration to the Proceedings of the US
Community Study on the Future of Particle Physics (Snowmass 2021).Comment: 27 pp. main text, 4 pp. appendices, 30 pp. reference
K2-291b:A rocky super-Earth in a 2.2 day orbit
K2-291 (EPIC 247418783) is a solar-type star with a radius of R_star = 0.899
0.034 R_sun and mass of M_star=0.934 0.038 M_sun. From K2 C13 data,
we found one super-Earth planet (R_p = 1.589+0.095-0.072 R_Earth) transiting
this star on a short period orbit (P = 2.225177 +6.6e-5 -6.8e-5 days). We
followed this system up with adaptive-optic imaging and spectroscopy to derive
stellar parameters, search for stellar companions, and determine a planet mass.
From our 75 radial velocity measurements using HIRES on Keck I and HARPS-N on
Telescopio Nazionale Galileo, we constrained the mass of EPIC 247418783b to M_p
= 6.49 1.16 M_Earth. We found it necessary to model correlated stellar
activity radial velocity signals with a Gaussian process in order to more
accurately model the effect of stellar noise on our data; the addition of the
Gaussian process also improved the precision of this mass measurement. With a
bulk density of 8.84+2.50-2.03 g cm-3, the planet is consistent with an
Earth-like rock/iron composition and no substantial gaseous envelope. Such an
envelope, if it existed in the past, was likely eroded away by
photo-evaporation during the first billion years of the star's lifetime.Comment: Accepted to AJ, 15 pages, 8 figure
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