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217,814 Matching Results

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Results: 1 - 24 of 217,814 next
Best Match Title Creator Date Created (Newest) Date Created (Oldest) Date Added (Newest) Date Added (Oldest)
0.25mm-Thick CCD Packaging for the Dark Energy Survey Camera Array (open access)

0.25mm-Thick CCD Packaging for the Dark Energy Survey Camera Array

Abstract: The Dark Energy Survey Camera focal plane array will consist of 62 2k x 4k CCDs with a pixel size of 15 microns and a silicon thickness of 250 microns for use at wavelengths between 400 and 1000 nm. Bare CCD die will be received from the Lawrence Berkeley National Laboratory (LBNL). At the Fermi National Accelerator Laboratory, the bare die will be packaged into a custom back-side-illuminated module design. Cold probe data from LBNL will be used to select the CCDs to be packaged. The module design utilizes an aluminum nitride readout board and spacer and an Invar foot. A module flatness of 3 microns over small (1 sqcm) areas and less than 10 microns over neighboring areas on a CCD are required for uniform images over the focal plane. A confocal chromatic inspection system is being developed to precisely measure flatness over a grid up to 300 x 300 mm. This system will be utilized to inspect not only room-temperature modules, but also cold individual modules and partial arrays through flat dewar windows.
Date: 2006-06~
Creator: Derylo, Greg; Diehl, H. Thomas & Estrada, Juan
Object Type: Article
System: The UNT Digital Library
0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology (open access)

0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology

Thermophotovoltaic (TPV) diodes fabricated from 0.52eV lattice-matched InGaAsSb alloys are grown by Metal Organic Vapor Phase Epitaxy (MOVPE) on GaSb substrates. 4cm{sup 2} multi-chip diode modules with front-surface spectral filters were tested in a vacuum cavity and attained measured efficiency and power density of 19% and 0.58 W/cm{sup 2} respectively at operating at temperatures of T{sub radiator} = 950 C and T{sub diode} = 27 C. Device modeling and minority carrier lifetime measurements of double heterostructure lifetime specimens indicate that diode conversion efficiency is limited predominantly by interface recombination and photon energy loss to the GaSb substrate and back ohmic contact. Recent improvements to the diode include lattice-matched p-type AlGaAsSb passivating layers with interface recombination velocities less than 100 cm/s and new processing techniques enabling thinned substrates and back surface reflectors. Modeling predictions of these improvements to the diode architecture indicate that conversion efficiencies from 27-30% and {approx}0.85 W/cm{sup 2} could be attained under the above operating temperatures.
Date: June 9, 2004
Creator: Dashiell, M. W.; Beausang, J. F.; Nichols, G.; Depoy, D. M.; Danielson, L. R.; Ehsani, H. et al.
Object Type: Report
System: The UNT Digital Library
[1 1/2 Story Rock House, (East elevation)]

[1 1/2 Story Rock House, (East elevation)]

Photograph of the 1 1/2 Story Rock House in Hilda, Texas.
Date: June 28, 1972
Creator: Kennedy, Craig
Object Type: Photograph
System: The Portal to Texas History
[1 1/2 Story Rock House, (Northwest oblique)]

[1 1/2 Story Rock House, (Northwest oblique)]

Photograph of the 1 1/2 Story Rock House in Hilda, Texas.
Date: June 28, 1972
Creator: Kennedy, Craig
Object Type: Photograph
System: The Portal to Texas History
[1 1/2 Story Rock House, (Southeast oblique)]

[1 1/2 Story Rock House, (Southeast oblique)]

Photograph of the 1 1/2 Story Rock House in Hilda, Texas.
Date: June 28, 1972
Creator: Kennedy, Craig
Object Type: Photograph
System: The Portal to Texas History
1 1/4 quick closing gate valve for fuel oil system

1 1/4 quick closing gate valve for fuel oil system

Blueprint depicting technical details of Battleship Texas.
Date: June 26, 1926
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1.1" Ammunition Hoists - Details of Loading Tables

1.1" Ammunition Hoists - Details of Loading Tables

Blueprint depicting technical details of Battleship Texas.
Date: June 30, 1941
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1.1" Ammunition Hoists - Watertight Door & Door Frame at Top

1.1" Ammunition Hoists - Watertight Door & Door Frame at Top

Blueprint depicting technical details of Battleship Texas.
Date: June 30, 1941
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1.5" Cast Steel Swing Check Valve Standard High Pressure 101 - 300 Lbs.

1.5" Cast Steel Swing Check Valve Standard High Pressure 101 - 300 Lbs.

Blueprint depicting technical details of Battleship Texas.
Date: June 16, 1926
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1.25" light and heavy pressure valve

1.25" light and heavy pressure valve

Blueprint depicting technical details of Battleship Texas.
Date: June 14, 1912
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1.25" light and heavy pressure valve

1.25" light and heavy pressure valve

Blueprint depicting technical details of Battleship Texas.
Date: June 14, 1912
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1.375" High Pressure Air Cylinder For 6" Torpedo Charger

1.375" High Pressure Air Cylinder For 6" Torpedo Charger

Blueprint depicting technical details of Battleship Texas.
Date: June 25, 1910
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
1- and 2-D computer analysis of an HDL stress wave switch, 1974, June 25 (open access)

1- and 2-D computer analysis of an HDL stress wave switch, 1974, June 25

None
Date: June 25, 1974
Creator: Mahler, J.
Object Type: Report
System: The UNT Digital Library
A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION (open access)

A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION

This paper describes electrical design criteria and first operational results a 140 kV, 1 MW average, 11 MW peak, zero-voltage-switching 20 kHz polyphase bridge, boost converter/modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2300 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three ''H-Bridge'' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. PWM (pulse width modulation) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt-peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. A review of these design parameters and the first results of the performance characteristics will be presented.
Date: June 1, 2001
Creator: Reass, W. A.; Doss, J. D. & Gribble, R. F.
Object Type: Article
System: The UNT Digital Library
1-MWE Heat Exchangers for OTEC Final Design Report (open access)

1-MWE Heat Exchangers for OTEC Final Design Report

The design of a 1 MWe OTEC heat exchanger is documented, including the designs of the evaporator and associated systems, condenser, instrumentation, and materials for corrosion/erosion control and fabrication processes. (LEW)
Date: June 19, 1980
Creator: Sprouse, A.M.
Object Type: Report
System: The UNT Digital Library
1 nA beam position monitoring system (open access)

1 nA beam position monitoring system

A system has been developed at Jefferson Lab for measuring transverse position of very low current beams delivered to the Experimental Hall B of the Continuous Electron Beam Accelerator Facility (CEBAF). At the heart of the system is a position sensitive cavity operating at 1497 MHz. The cavity utilizes a unique design which achieves a high sensitivity to beam position at a relatively low cavity Q. The cavity output RF signal is processed using a down-converter and a commercial lock-in amplifier operating at 100 kHz. The system interfaces with a VME based EPICS control system using the IEEE, 488 bus. The main features of the system are simple and robust design, and wide dynamic range capable of handling beam currents from 1 nA to 1000 nA with an expected resolution better than 100 {mu}m. This paper outlines the design of the system.
Date: June 1, 1997
Creator: Ursic, R.; Flood, R. & Piller, C.
Object Type: Article
System: The UNT Digital Library
A 1- to 5-MW, RCS-based, short-pulse spallation neutron source (open access)

A 1- to 5-MW, RCS-based, short-pulse spallation neutron source

Two accelerator configurations, the linac/compressor ring scheme and the linac/RCS scheme, are commonly used to provide the proton beam power for a short-pulse spallation neutron source. In one configuration, a full-power linac provides the beam power and a compressor ring shortens the pulse length from 1-ms down to 1 {micro}s. In the other, rapid cycling synchrotrons (RCSs) provide the beam power and also shorten the pulse length. A feasibility study of a staged approach to a 5-MW proton source utilizing RCS technology, allowing intermediate operation at 1 MW, was performed at ANL and is presented in this paper. This study is complementary to a study in progress at ORNL based on a linac and an accumulator ring. The 1-MW facility consists of a 400-MeV injector linac that delivers 0.5-mA time-averaged current, a synchrotron that accelerates the beam to 2 GeV at a 30-Hz rate, and two neutron-generating target stations. In the second phase, the 2-GeV beam is accelerated to 10 GeV by a larger RCS, increasing the facility beam power to 5 MW.
Date: June 1997
Creator: Cho, Y.; Chae, Y.-C. & Crosbie, E.
Object Type: Article
System: The UNT Digital Library
2.1 Pan-WCRP Monsoon Modelling Workshop Summary (open access)

2.1 Pan-WCRP Monsoon Modelling Workshop Summary

Ken Sperber led a discussion of the outcome of the Pan-WCRP Monsoon Modelling Workshop that was held at the University of California at Irvine from 15-17 June 2005. At the workshop presentations from key CLIVAR and GEWEX panels were presented to highlight the outstanding problems in modelling the Earth's monsoons. Additionally, presentations from invited experts were given to highlight important aspects of monsoon phenomena and processes, such as low-level jets, air-sea interaction, predictability, observational networks/studies, and model test beds etc. Since all persons attending the CLIVAR AAMP meeting were present for all, or most, of the monsoon workshop, a detailed description of the workshop presentations was not given. Rather, the discussion was focused on the recommendations of the workshop breakout groups and their relevance to CLIVAR AAMP. CLIVAR AAMP endorsed the near-term workshop recommendation of investigating the diurnal cycle using a hierarchy of models a key way forward for promoting CLIVAR/GEWEX interactions. In GCM studies CLIVAR researchers have identified the diurnal cycle as a forced ''mode'' of variability that is poorly represented in terms of amplitude and phase, especially in the case of precipitation. Typical phase errors of 6-12 hours are noted over both land and ocean in GCMs. CLIVAR …
Date: June 28, 2005
Creator: Sperber, K R
Object Type: Report
System: The UNT Digital Library
2-D or not 2-D, that is the question: A Northern California test (open access)

2-D or not 2-D, that is the question: A Northern California test

Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance …
Date: June 6, 2005
Creator: Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R & Dreger, D
Object Type: Article
System: The UNT Digital Library
A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors (open access)

A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors

This paper will focus on the methodology of using a 2D plasma Direct Simulation Monte Carlo technique to simulate the species transport in an inductively coupled, low pressure, chemically reacting plasma system. The pressure in these systems is typically less than 20 mtorr with plasma densities of approximately 10{sup 17} {number_sign}/m{sup 3} and an ionization level of only 0.1%. This low ionization level tightly couples the neutral, ion, and electron chemistries and interactions in a system where the flow is subsonic. We present our strategy and compare simulation results to experimental data for Cl{sub 2} in a Gaseous Electronics Conference (GEC) reference cell modified with an inductive coil.
Date: June 17, 1999
Creator: Bartel, Timothy J.; Economou, Demetre & Johannes, Justine E.
Object Type: Article
System: The UNT Digital Library
2" heavy pressure valve

2" heavy pressure valve

Blueprint depicting technical details of Battleship Texas.
Date: June 10, 1912
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
2" Horizontal Volute Pump Circulating Pump (Jeansville Iron Works)

2" Horizontal Volute Pump Circulating Pump (Jeansville Iron Works)

Blueprint depicting technical details of Battleship Texas.
Date: June 25, 1914
Creator: unknown
Object Type: Technical Drawing
System: The Portal to Texas History
A 2-Megawatt load for testing high voltage dc power supplies (open access)

A 2-Megawatt load for testing high voltage dc power supplies

A high power water-cooled resistive load, capable of dissipating 2 Megawatts at 95 kilovolts is being designed and built. The load utilizes wirewound resistor elements suspended inside insulating tubing contained within a pressure vessel which is supplied a continuous flow of deionized water for coolant. A sub-system of the load is composed of non-inductive resistor elements in an oil tank. Power tests conducted on various resistor types indicate that dissipation levels as high as 22 times the rated dissipation in air can be achieved when the resistors are placed in a turbulent water flow of at least 15 gallons per minute. Using this data, the load w.as designed using 100 resistor elements in a series arrangement A single-wall 316 stainless steel pressure vessel with flanged torispherical heads is built to contain the resistor assembly and deionized water. The resistors are suspended within G-11 tubing which span the cylindrical length of the vessel. These tubes are supported by G-10 baffles which also increase convection from the tubes by promoting turbulence within the surrounding water.
Date: June 1, 1993
Creator: Horan, D.; Kustom, R.; Ferguson, M. & Primdahl, K.
Object Type: Article
System: The UNT Digital Library
A 2-MV multi-beam injector for heavy ion fusion (open access)

A 2-MV multi-beam injector for heavy ion fusion

Construction of a sixteen beam (0.5 A per beam) injector for use in scaled heavy ion fusion experiments is underway at LBL. The machine was designed and partially constructed at LANL. The injector is designed to use carbon arc sources which will provide 25 mA/cm/sup 2/ of extractable current density. The plasma from the arcs is confined electrostatically from drifting into the ion gun before firing the extraction pulse. The acceleration column consists of a set of aperture lenses which both transport the beam and attenuate backstreaming electrons. The acceleration column is mounted inside a 28-inch diameter brazed alumina insulating module. The high voltage for the injector is provided by an inductively loaded and graded Marx generator which resides inside a pressure vessel filled with a 65 psig mixture of 30/percent/ SF/sub 6/ and 70/percent/ N/sub 2/. Data is presented showing the performance of single and multiple carbon arc sources. Measurements show that adequate current density is available. Emittance measurements and efforts to improve emittance and reproducibility are shown. Tests with a 5-tray section of the full 18 tray generator are described showing the evolution of the generator design. 5 refs., 3 figs.
Date: June 1, 1988
Creator: Rutkowski, H. L.; Faltens, A.; Vanecek, D.; Pike, C.; Humphries, S., Jr. & Meyer, E. A.
Object Type: Article
System: The UNT Digital Library