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The yeast lipin orthologue Pah1p is important for biogenesis of lipid droplets (open access)

The yeast lipin orthologue Pah1p is important for biogenesis of lipid droplets

Article on yeast lipin orthologue Pah1p and its importance for biogenesis of lipid droplets.
Date: March 21, 2011
Creator: Adeyo, Oludotun; Horn, Patrick J.; Lee, SungKyung; Binns, Derk Douglas; Chandrahas, Anita; Chapman, Kent D. et al.
System: The UNT Digital Library
Proposed RF Breakdown Studies at the AWA (open access)

Proposed RF Breakdown Studies at the AWA

A study of breakdown mechanism has been initiated at the Argonne Wakefield Accelerator (AWA). Breakdown may include several factors such as local field enhancement, explosive electron emission, Ohmic heating, tensile stress produced by electric field, and others. The AWA is building a dedicated facility to test various models for breakdown mechanisms and to determine the roles of different factors in the breakdown. We plan to trigger breakdown events with a high-powered laser at various wavelengths (IR to UV) to determine the role of explosive electron emission in the breakdown process. Another experimental idea follows from the recent work on a Schottky-enabled photoemission in an RF photoinjector [1] that allows us to determine in situ the field enhancement factor on a cathode surface. Monitoring the field enhancement factor before and after the breakdown can shed some light on a number of observations such as the crater formation process.
Date: March 21, 2007
Creator: Antipov, S.; Conde, M.; Gai, W.; Power, J. G.; Spentzouris, L.; Yusof, Z. et al.
System: The UNT Digital Library
Development of a High Level Waste Tank Inspection System (open access)

Development of a High Level Waste Tank Inspection System

The Westinghouse Savannah River Technology Center was requested by it`s sister site, West Valley Nuclear Service (WVNS), to develop a remote inspection system to gather wall thickness readings of their High Level Waste Tanks. WVNS management chose to take a proactive approach to gain current information on two tanks t hat had been in service since the early 70`s. The tanks contain high level waste, are buried underground, and have only two access ports to an annular space between the tank and the secondary concrete vault. A specialized remote system was proposed to provide both a visual surveillance and ultrasonic thickness measurements of the tank walls. A magnetic wheeled crawler was the basis for the remote delivery system integrated with an off-the-shelf Ultrasonic Data Acquisition System. A development program was initiated for Savannah River Technology Center (SRTC) to design, fabricate, and test a remote system based on the Crawler. The system was completed and involved three crawlers to perform the needed tasks, an Ultrasonic Crawler, a Camera Crawler, and a Surface Prep Crawler. The crawlers were computer controlled so that their operation could be done remotely and their position on the wall could be tracked. The Ultrasonic Crawler controls were …
Date: March 21, 1995
Creator: Appel, D. K.; Loibl, M. W. & Meese, D. C.
System: The UNT Digital Library
Production and Decay of Omega_c^0 (open access)

Production and Decay of Omega_c^0

We present an analysis of inclusive {Omega}{sub c}{sup 0} baryon production and decays in 230.5 fb{sup -1} of data recorded with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the Stanford Linear Accelerator Center. {Omega}{sub c}{sup 0} baryons are reconstructed in four final states ({Omega}{sup -}{pi}{sup +}, {Omega}{sup -}{pi}{sup +}{pi}{sup 0}, {Omega}{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -}, {Xi}{sup -}K{sup -}{pi}{sup +}{pi}{sup +}) and the ratios of branching fractions for these final states are measured. We also measure the momentum spectrum of the {Omega}{sub c}{sup 0} baryons in the e{sup +}e{sup -} center-of-mass frame. From the spectrum, they observe {Omega}{sub c}{sup 0} production from B decays and in c{bar c} events, and extract the two rates of production.
Date: March 21, 2007
Creator: Aubert, B.
System: The UNT Digital Library
Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems (open access)

Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems

We propose and analyze a new tool to help solve sparse linear least-squares problems min{sub x} {parallel}Ax-b{parallel}{sub 2}. Our method is based on a sparse QR factorization of a low-rank perturbation {cflx A} of A. More precisely, we show that the R factor of {cflx A} is an effective preconditioner for the least-squares problem min{sub x} {parallel}Ax-b{parallel}{sub 2}, when solved using LSQR. We propose applications for the new technique. When A is rank deficient we can add rows to ensure that the preconditioner is well-conditioned without column pivoting. When A is sparse except for a few dense rows we can drop these dense rows from A to obtain {cflx A}. Another application is solving an updated or downdated problem. If R is a good preconditioner for the original problem A, it is a good preconditioner for the updated/downdated problem {cflx A}. We can also solve what-if scenarios, where we want to find the solution if a column of the original matrix is changed/removed. We present a spectral theory that analyzes the generalized spectrum of the pencil (A*A,R*R) and analyze the applications.
Date: March 21, 2008
Creator: Avron, Haim; Ng, Esmond G. & Toledo, Sivan
System: The UNT Digital Library
EXPECTED TRIGGER RATES OF HIGH PT JETS AND DIRECT PHOTONS IN THE STAR EMC. (open access)

EXPECTED TRIGGER RATES OF HIGH PT JETS AND DIRECT PHOTONS IN THE STAR EMC.

The STAR experiment at RHIC is a large acceptance detector. The electromagnetic calorimeter (EMC) will provide a sensitive trigger to study high p{sub t} jets and hard photons in AuAu, pp, and pAu collisions. The capability for the EMC to trigger on jets and direct photons was studied for trigger level 0. Trigger efficiencies and expected process rates were obtained for pp reactions. Results from pp interactions will be essential to the interpretation of AuAu results as well as for the spin physics program. These studies were performed with the standard STAR software chain which includes GEANT and EMC simulations. The HIJING event generator was used to provide input for the simulations.
Date: March 21, 1999
Creator: BELT-TONJES,M. FOR THE STAR COLLABORATION
System: The UNT Digital Library
General Dynamics Convair Division approach to structural analysis of large superconducting coils (open access)

General Dynamics Convair Division approach to structural analysis of large superconducting coils

Most of the procedures and techniques described were developed over the past three years. Starting in late 1976, development began on high-accuracy computer codes for electromagnetic field and force analysis. This effort resulted in completion of a family of computer programs called MAGIC (MAGnetic Integration Calcaultion). Included in this group of programs is a post-processor called POSTMAGIC that links MAGIC to GDSAP (General Dynamics Structural Analysis Program) by automatically transferring force data. Integrating these computer programs afforded us the capability to readily analyze several different conditions that are anticipated to occur during tokamak operation. During 1977 we initiated the development of the CONVERT program that effectively links our THERMAL ANALYZER program to GDSAP by automatically transferring temperature data. The CONVERT program allowed us the capability to readily predict thermal stresses at several different time phases during the computer-simulated cooldown and warmup cycle. This feature aided us in determining the most crucial time phases and to adjust recommended operating procedure to minimize risk.
Date: March 21, 1979
Creator: Baldi, R.W.
System: The UNT Digital Library
Accessing the Inaccessible: The Case for Opening up Russia's Closed Cities (open access)

Accessing the Inaccessible: The Case for Opening up Russia's Closed Cities

The selling of weapons-related nuclear knowledge by Russian scientists for economic gain constitutes a threat to US national security. Some estimate that the number of Russian scientists seeking permanent employment abroad constitute five to ten percent of all researchers who have left the field of science. And, there is concern that those who have left are ''the better minds.'' Moreover, the issue of brain drain concerns not only those who move abroad permanently, but those who still reside in Russia and travel abroad to sell their knowledge. Of particular concern to the US is the potential sale of WMD knowledge by some. To ''mitigate the risk that economic difficulties...might create the temptation for individuals or institutes to sell expertise to countries of proliferation concern and terrorist organizations,'' the Department of Energy launched a Nuclear Cities Initiative (NCI) in 1998 with the goal of creating commercial jobs and economic diversification in the ten closed cities that form the core of Russia's nuclear weapons complex to accommodate the loss of employment in the nuclear weapons industry. However, unless Russia opens access to the areas of its closed cities that are, or could become, involved in commercial activities-while of course carefully controlling access …
Date: March 21, 2001
Creator: Ball, D Y
System: The UNT Digital Library
Nuclear desalination plant control studies (open access)

Nuclear desalination plant control studies

None
Date: March 21, 1973
Creator: Ball, S. J.; Clapp, N. E., Jr. & Delene, J. G.
System: The UNT Digital Library
Comments on Reservoir Technology, DOE PR VII, San Francisco, March 23, 1989 (open access)

Comments on Reservoir Technology, DOE PR VII, San Francisco, March 23, 1989

My assignment is to give feedback on the Reservoir Technology Task portion of the DOE-sponsored work we've been hearing about. Briefly, you've done well in adapting to an increasingly tough budgetary and political environment. More specifically, I'd like to highlight some of the encouraging developments in the context of overall research strategy. Ted Mock on Tuesday and Ken Nemzer at yesterday's luncheon made several useful observations and I'd like to refer to just two in relation to Reservoir Technology. Ted observed that product development can proceed along two paths. We might call these the Big Bang or the Evolutionary lines. He correctly pointed out the difficulty American industry has had with commercializing incremental (Evolutionary) product improvements. In this context Reservoir Technology development is more like manufacturing engineering because we aren't developing new products, for the most part. We are simply working to produce electricity or process heat cheaper. The DOE has listened to industry on this point and their statement of objectives sounds excellent. Let me quote one example from Page 10 of the December 20, 1988 report. For ''Reservoir Evaluation'' we read ''Decrease uncertainties...20% by 1993''. I confess that I don't know what the uncertainty is in 1989, but …
Date: March 21, 1989
Creator: Barker, B.J.
System: The UNT Digital Library
Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b (open access)

Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b

Using the integral field spectrograph OSIRIS, on the Keck II telescope, broad near-infrared H and K-band spectra of the young exoplanet HR8799b have been obtained. In addition, six new narrow-band photometric measurements have been taken across the H and K bands. These data are combined with previously published photometry for an analysis of the planet's atmospheric properties. Thick photospheric dust cloud opacity is invoked to explain the planet's red near-IR colors and relatively smooth near-IR spectrum. Strong water absorption is detected, indicating a Hydrogen-rich atmosphere. Only weak CH{sub 4} absorption is detected at K band, indicating efficient vertical mixing and a disequilibrium CO/CH{sub 4} ratio at photospheric depths. The H-band spectrum has a distinct triangular shape consistent with low surface gravity. New giant planet atmosphere models are compared to these data with best fitting bulk parameters, T{sub eff} = 1100K {+-} 100 and log(g) = 3.5 {+-} 0.5 (for solar composition). Given the observed luminosity (log L{sub obs}/L{sub {circle_dot}} {approx} -5.1), these values correspond to a radius of 0.75 R{sub Jup{sub 0.12}{sup +0.17}} and mass {approx} 0.72 M{sub Jup{sub -0.6}{sup +2.6}} - strikingly inconsistent with interior/evolution models. Enhanced metallicity (up to {approx} 10 x that of the Sun) along with …
Date: March 21, 2011
Creator: Barman, T. S.; Macintosh, B. A.; Konopacky, Q. M. & Marois, C.
System: The UNT Digital Library
Bounds on Transport Coefficients of Porous Media (open access)

Bounds on Transport Coefficients of Porous Media

An analytical formulation of conductivity bounds by Bergman and Milton is used in a different way to obtain rigorous bounds on the real transport coefficients (electrical conductivity, thermal conductivity, and/or fluid permeability) of a fluid-saturated porous medium. These bounds do not depend explicitly on the porosity, but rather on two formation factors--one associated with the pore space and the other with the solid frame. Hashin-Shtrikman bounds for transport in random polycrystals of porous-material laminates will also be discussed.
Date: March 21, 2005
Creator: Berger, E. L.
System: The UNT Digital Library
Top spin and experimental tests (open access)

Top spin and experimental tests

The authors examine pair mass dependence near threshold as a means to measure the spin of the top quark in hadron collisions, and they discuss the possibility that a top quark signal could be hidden among the top events.
Date: March 21, 2000
Creator: Berger, E. L. & Tait, T. M. P.
System: The UNT Digital Library
Hot Dry Rock Overview at Los Alamos (open access)

Hot Dry Rock Overview at Los Alamos

The Hot Dry Rock (HDR) geothermal energy program is a renewable energy program that can contribute significantly to the nation's balanced and diversified energy mix. Having extracted energy from the first Fenton Hill HDR reservoir for about 400 days, and from the second reservoir for 30 days in a preliminary test, Los Alamos is focusing on the Long Term Flow Test and reservoir studies. Current budget limitations have slowed preparations thus delaying the start date of that test. The test is planned to gather data for more definitive reservoir modeling with energy availability or reservoir lifetime of primary interest. Other salient information will address geochemistry and tracer studies, microseismic response, water requirements and flow impedance which relates directly to pumping power requirements. During this year of ''preparation'' we have made progress in modeling studies, in chemically reactive tracer techniques, in improvements in acoustic or microseismic event analysis.
Date: March 21, 1989
Creator: Berger, Michael & Hendron, Robert H.
System: The UNT Digital Library
Operando tribochemical formation of onion-likecarbon leads to macroscale superlubricity (open access)

Operando tribochemical formation of onion-likecarbon leads to macroscale superlubricity

This article demonstrates that tribochemical reactions occur even in dry conditions when hydrogenated diamond-like carbon (H-DLC) surface is slid against two-dimensional (2D) molybdenum disulfide along with nanodiamonds in dry nitrogen atmosphere.
Date: February 3, 2017
Creator: Berman, Diana; Narayanan, Badri; Cherukara, Mathew J.; Sankaranarayanan, Subramanian K.R.S.; Erdemir, Ali; Zinovev, Alexander et al.
System: The UNT Digital Library
Advanced Binary Geothermal Power Plancts Working Fluid Property Determination and Heat Exchanger Design (open access)

Advanced Binary Geothermal Power Plancts Working Fluid Property Determination and Heat Exchanger Design

The performance of binary geothermal power plants can be improved through the proper choice of a working fluid, and optimization of component designs and operating conditions. This paper reviews the investigations at the Idaho National Engineering Laboratory (INEL) which are examining binary cycle performance improvements: for moderate temperature (350 to 400 F) resources with emphasis on how the improvements may be integrated into design of binary cycles. These investigations are examining performance improvements resulting from the supercritical vaporization of mixed hydrocarbon working fluids and achieving countercurrent integral condensation with these fluids, as well as the modification of the turbine inlet state points to achieve supersaturated turbine vapor expansions. For resources where the brine outlet temperature is restricted, the use of turbine exhaust recuperators is examined. The baseline plant used to determine improvements in plant performance (characterized by the increase in the net brine effectiveness, watt-hours per pound of brine) in these studies operates at conditions similar to the 45 MW Heber binary plant. Through the selection of the optimum working fluids and operating conditions, achieving countercurrent integral condensation, and allowing supersaturated vapor expansions in the turbine, the performance of the binary cycle (the net brine effectiveness) can be improved by …
Date: March 21, 1989
Creator: Bliem, C.J. & Mines, G.L.
System: The UNT Digital Library
2006 Sensory Transduction in Microorganisms Gordon Conference - January 22-27 (open access)

2006 Sensory Transduction in Microorganisms Gordon Conference - January 22-27

This Report is Description of Sensory Transduction in Microorganisms at Gordon Conference.
Date: March 21, 2007
Creator: Borkovich, Katherine
System: The UNT Digital Library
Flash Vacuum Pyrolysis of Lignin Model Compounds: Reaction Pathways of Aromatic Methoxy Groups (open access)

Flash Vacuum Pyrolysis of Lignin Model Compounds: Reaction Pathways of Aromatic Methoxy Groups

Currently, there is interest in utilizing lignin, a major constituent of biomass, as a renewable source of chemicals and fuels. High yields of liquid products can be obtained from the flash or fast pyrolysis of biomass, but the reaction pathways that lead to product formation are not understood. To provide insight into the primary reaction pathways under process relevant conditions, we are investigating the flash vacuum pyrolysis (FVP) of lignin model compounds at 500 C. This presentation will focus on the FVP of {beta}-ether linkages containing aromatic methoxy groups and the reaction pathways of methoxy-substituted phenoxy radicals.
Date: March 21, 1999
Creator: Britt, P. F.; Buchanan, A. C., III & Martineau, D. R.
System: The UNT Digital Library
Reservoir Modeling for Production Management (open access)

Reservoir Modeling for Production Management

For both petroleum and geothermal resources, many of the reservoirs are fracture dominated--rather than matrix-permeability controlled. For such reservoirs, a knowledge of the pressure-dependent permeability of the interconnected system of natural joints (i.e., pre-existing fractures) is critical to the efficient exploitation of the resource through proper pressure management. Our experience and that reported by others indicates that a reduction in the reservoir pressure sometimes leads to an overall reduction in production rate due to the ''pinching off'' of the joint network, rather than the anticipated increase in production rate. This effect occurs not just in the vicinity of the wellbore, where proppants are sometimes employed, but throughout much of the reservoir region. This follows from the fact that under certain circumstances, the decline in fracture permeability (or conductivity) with decreasing reservoir pressure exceeds the far-field reservoir ''drainage'' flow rate increase due to the increased pressure gradient. Further, a knowledge of the pressure-dependent joint permeability could aid in designing more appropriate secondary recovery strategies in petroleum reservoirs or reinjection procedures for geothermal reservoirs.
Date: March 21, 1989
Creator: Brown, Donald W.
System: The UNT Digital Library
THE YEAR-ONE PHYSICS CAPABILITIES OF STAR. (open access)

THE YEAR-ONE PHYSICS CAPABILITIES OF STAR.

When the Relativistic Heavy Ion Collider (RHIC) at BNL begins operation in the Fall of 1999, heavy ions will be accelerated in collider mode for the first time, and a new energy regime will be entered for Heavy Ion Physics. The Solenoidal Tracker At RHIC (STAR) detector has a near 4{pi} coverage and is dedicated to taking hadronic measurements. A large volume Time Projection Chamber placed in a solenoidal magnet at 0.5T is used to track and identify the many thousands of produced particles. STAR will measure many observables simultaneously on an event-by-event basis to study signatures of a possible QGP phase transition and the space-time evolution of the collision process. The goal is to obtain a fundamental understanding of the microscopic structure of hadronic interactions, at the level of quarks and gluons, at high energy densities. This paper outlines the physics STAR intends to study during the first year of operation.
Date: March 21, 1999
Creator: CAINES,H. FOR THE STAR COLLABORATION
System: The UNT Digital Library
Portal 6.0 Released!! (open access)

Portal 6.0 Released!!

None
Date: March 21, 2011
Creator: Cantor, Michael & Smirnova, Tatyana
System: The UNT Digital Library
Deep Borehole Measurements for Characterizing the Magma/Hydrothermal System at Long Valley Caldera, CA (open access)

Deep Borehole Measurements for Characterizing the Magma/Hydrothermal System at Long Valley Caldera, CA

The Magma Energy Program of the Geothermal Technology Division is scheduled to begin drilling a deep (6 km) exploration well in Long Valley Caldera, California in 1989. The drilling site is near the center of the caldera which is associated with numerous shallow (5-7 km) geophysical anomalies. This deep well will present an unparalleled opportunity to test and validate geophysical techniques for locating magma as well as a test of the theory that magma is still present at drillable depths within the central portion of the caldera. If, indeed, drilling indicates magma, the geothermal community will then be afforded the unique possibility of examining the coupling between magmatic and hydrothermal regimes in a major volcanic system. Goals of planned seismic experiments that involve the well include the investigation of local crustal structure down to depths of 10 km as well as the determination of mechanisms for local seismicity and deformation. Borehole electrical and electromagnetic surveys will increase the volume and depth of rock investigated by the well through consideration of the conductive structure of the hydrothermal and underlying regimes. Currently active processes involving magma injection will be studied through observation of changes in pore pressure and strain. Measurements of in …
Date: March 21, 1989
Creator: Carrrigan, Charles R.
System: The UNT Digital Library
Laser powder bed fusion processing of a precipitation strengthenable FCC based high entropy alloy (open access)

Laser powder bed fusion processing of a precipitation strengthenable FCC based high entropy alloy

Article describes how, while additive manufacturing (AM) of single-phase solid solution based high entropy alloys (HEAs) has attracted a lot of recent attention, such processing of precipitation strengthenable multi-phase HEAs has not been actively investigated. This becomes important since AM processing results in each layer experiencing rapid solidification followed by multiple heating-cooling cycles, mimicking in situ heat treatments, potentially influencing the phase evolution.
Date: March 21, 2023
Creator: Chesetti, Advika; Banerjee, Sucharita; Dasari, Sriswaroop; Varahabhatla, S.M.; Sharma, Abhishek; Mantri, Srinivas Aditya et al.
System: The UNT Digital Library
BOUT Simulations of Edge Turbulence in the DIII-D Tokamak (open access)

BOUT Simulations of Edge Turbulence in the DIII-D Tokamak

None
Date: March 21, 2012
Creator: Cohen, B. I.; Umansky, M.; Makowski, M.; Nevins, W. M.; Boedo, J.; Rudakov, D. et al.
System: The UNT Digital Library