Partner
Collection
Country
States
Language
Results:
1 - 24 of
97
next
A Terrestrial Search for Dark Contents of the Vacuum, Such as Dark Energy, Using Atom Interferometry
We describe the theory and first experimental work on our concept for searching on earth for the presence of dark contents of the vacuum (DCV) using atom interferometry. Specifically, we have in mind any DCV that has not yet been detected on a laboratory scale, but which might manifest itself as dark energy on the cosmological scale. The experimental method uses two atom interferometers to cancel the effect of earth's gravity and diverse noise sources. It depends upon two assumptions: first, that the DCV possesses some space inhomogeneity in density, and second that it exerts a sufficiently strong nongravitational force on matter. The motion of the apparatus through the DCV should then lead to an irregular variation in the detected matter-wave phase shift. We discuss the nature of this signal and note the problem of distinguishing it from instrumental noise. We also discuss the relation of our experiment to what might be learned by studying the noise in gravitational wave detectors such as LIGO. The paper concludes with a projection that a future search of this nature might be carried out using an atom interferometer in an orbiting satellite. The laboratory apparatus is now being constructed.
Date:
June 11, 2012
Creator:
Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Muller, Holger; /UC, Berkeley; Perl, Martin L. & /KIPAC, Menlo Park /SLAC
Object Type:
Article
System:
The UNT Digital Library
Assessment of an ORION-based experimental platform for measuring the opacity of high-temperature and high-density plasma
The following provides an assessment of an experimental platform based on the ORION laser at AWE Aldermasten, England, for measuring the opacity of high-temperature and high-density LTE plasmas. The specific points addressed are (1) the range of electron density and temperature that can be achieved with short-pulse beams alone, as well as (2) by means of compression with a long-pulse beam; (3) the accuracy with which electron density, electron temperature, and absolute emissivity can be measured; (4) the use of pulse shaping to increase the sample density to above solid density; (5) the effect that target materials and target design have on maintaining spatial uniformity of the sample, and (6) the need for additional diagnostics to produce and characterize samples for decisive measurements.
Date:
June 11, 2012
Creator:
Beiersdorfer, P; Schneider, M & Shepherd, R
Object Type:
Report
System:
The UNT Digital Library
Novel wide band gap materials for highly efficient thin film tandem solar cells
Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV’s goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device …
Date:
June 11, 2012
Creator:
Brian E. Hardin, Stephen T. Connor, Craig H. Peters
Object Type:
Report
System:
The UNT Digital Library
The American Opportunity Tax Credit: Overview, Analysis, and Policy Options
This report gives an overview of the American Opportunity Tax Credit (AOTC)—enacted on a temporary basis by the American Recovery and Reinvestment Act and extended through the end of 2012 by the Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010— which is a partially-refundable tax credit that provides financial assistance to taxpayers who are attending college, or whose children are attending college. There are a variety of policy options mentioned in the report regarding the AOTC, including extending the credit, extending a modified AOTC, or repealing the Hope and Lifetime Credits and extending a modified AOTC that includes provisions included in these credits.
Date:
June 11, 2012
Creator:
Crandall-Hollick, Margot L.
Object Type:
Report
System:
The UNT Digital Library
Initial Evaluation of Processing Methods for an Epsilon Metal Waste Form
During irradiation of nuclear fuel in a reactor, the five metals, Mo, Pd, Rh, Ru, and Tc, migrate to the fuel grain boundaries and form small metal particles of an alloy known as epsilon metal ({var_epsilon}-metal). When the fuel is dissolved in a reprocessing plant, these metal particles remain behind with a residue - the undissolved solids (UDS). Some of these same metals that comprise this alloy that have not formed the alloy are dissolved into the aqueous stream. These metals limit the waste loading for a borosilicate glass that is being developed for the reprocessing wastes. Epsilon metal is being developed as a waste form for the noble metals from a number of waste streams in the aqueous reprocessing of used nuclear fuel (UNF) - (1) the {var_epsilon}-metal from the UDS, (2) soluble Tc (ion-exchanged), and (3) soluble noble metals (TRUEX raffinate). Separate immobilization of these metals has benefits other than allowing an increase in the glass waste loading. These materials are quite resistant to dissolution (corrosion) as evidenced by the fact that they survive the chemically aggressive conditions in the fuel dissolver. Remnants of {var_epsilon}-metal particles have survived in the geologically natural reactors found in Gabon, Africa, indicating …
Date:
June 11, 2012
Creator:
Crum, Jarrod V.; Strachan, Denis M. & Zumhoff, Mac R.
Object Type:
Report
System:
The UNT Digital Library
Medicare: History of Insolvency Projections
This Congressional Research Service Report for Congress details Medicare Hospital Insurance (HI) financing as well as history of solvency and current insolvency projections.
Date:
June 11, 2012
Creator:
Davis, Patrica A.
Object Type:
Report
System:
The UNT Digital Library
Relating B_S Mixing and B_S to mu+mu- with New Physics
We perform a study of the standard model fit to the mixing quantities {Delta}M{sub B{sub s}}, and {Delta}{Lambda}{sub B{sub s}}/{Delta}M{sub B{sub s}} in order to bound contributions of new physics (NP) to B{sub s} mixing. We then use this to explore the branching fraction of B{sub s} {yields} {mu}{sup +}{mu}{sup -} in certain models of NP. In most cases, this constrains NP amplitudes for B{sub s} {yields} {mu}{sup +}{mu}{sup -} to lie below the standard model component.
Date:
June 11, 2012
Creator:
Golowich, Eugene; Hewett, JoAnne; Pakvasa, Sandip; Petrov, Alexey A. & Yeghiyan, Gagik K.
Object Type:
Article
System:
The UNT Digital Library
[News Clip: 500,000th Guest]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Arkansas Win]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Arlington Case]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Arlington Elderly Case]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Arlington Homicide]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Arlington Murder]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Baseball News]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Bon Jovi]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Children Golfing]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: CLE vs PIT]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Crime Report]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Degree Forgery]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Detectives]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Discrimination]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Donation]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Farmers]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
[News Clip: Farming]
B-roll video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
June 11, 2012
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library