Resource Type

0-G experiments with advanced ceramic fabric wick structures (open access)

0-G experiments with advanced ceramic fabric wick structures

Both Air Force and NASA future spacecraft thermal management needs span the temperature range from cryogenic to liquid metals. Many of these needs are changing and not well defined and will remain so until goals, technology, and missions converge. Nevertheless, it is certain that high-temperature (> 800 K) and medium-temperature (about 450 K) radiator systems will have to be developed that offer significant improvements over current designs. This paper discusses experiments performed in the lower temperature regime as part of a comprehensive advanced ceramic fabric (ACF) heat pipe development program. These experiments encompassed wicking tests with various ceramic fabric samples, and heat transfer tests with a 1-m long prototype ACF water heat pipe. A prototype ceramic fabric/titanium water heat pipe has been constructed and tested; it transported up to 60 W of power at about 390 K. Startup and operation both with and against gravity examined. Wick testing was begun to aid in the design and construction of an improved prototype heat pipe, with a 38-{mu}m stainless steel linear covered by a biaxially-braided Nextel (trademark of the 3M Co., St. Paul, Minnesota) sleeve that is approximately 300-{mu}m thick. Wick testing took place in 1-g; limited testing in 0-g was initiated, …
Date: July 1991
Creator: Antoniak, Z. I.; Webb, B. J.; Bates, J. M.; Cooper, M. F. & Pauley, K. A.
System: The UNT Digital Library
1. 2-GeV damping-ring complex for the Stanford Linear Collider (open access)

1. 2-GeV damping-ring complex for the Stanford Linear Collider

The choice of parameters, the design, a 2-1/2 year consruction program and the early operation of a high field, high tune research and development damping ring complex for one of the two linear collider beams are described.
Date: July 1983
Creator: Fischer, G. E.; Davies-White, W.; Fieguth, T. & Wiedemann, H.
System: The UNT Digital Library
1.5-GEV FFAG ACCELERATOR AS INJECTOR TO THE BNL-AGS. (open access)

1.5-GEV FFAG ACCELERATOR AS INJECTOR TO THE BNL-AGS.

A 1.5-GeV Fixed-Field Alternating-Gradient (FFAG) proton Accelerator is being studied as a new injector to the Alternating-Gradient Synchrotron (AGS) of Brookhaven National Laboratory (BNL). The major benefit is that it would considerably shorten the overall AGS acceleration cycle, and, consequently, may yield to an improvement of beam stability, intensity and size. The AGS-FFAG will also facilitate the proposed upgrade of the AGS facility toward a 1-MW average proton beam power at the top energy of 28 GeV. This paper describes the FFAG design for acceleration of protons from 400 MeV to 1.5 GeV, with the same circumference of the AGS, and entirely housed in the AGS tunnel.
Date: July 5, 2004
Creator: Ruggiero, A. G.; Blaskiewicz, M.; Trbojevic, D.; Tsoupas, N. & Zhang, W.
System: The UNT Digital Library
1/5-scale experiment of a Mark I boiling-water reactor pressure-suppression system under hypothetical LOCA conditions (open access)

1/5-scale experiment of a Mark I boiling-water reactor pressure-suppression system under hypothetical LOCA conditions

Experimental results show the sensitivity of hydrodynamically generated vertical loads to changes in the drywell pressurization rate, downcomer submergence, and vent-line loss coefficient. Insignificant effects on peak vertical loads were observed when the vent-line loss was varied. Peak vertical loads can be reduced by adding initial drywell overpressure so that the downcomers are partly cleared of water. Spatial variation of pressure at about the time of vent clearing is seen in comparisons of data from locations along the axis of the toroidal wetwell.
Date: July 8, 1977
Creator: Pitts, J. H. & McCauley, E. W.
System: The UNT Digital Library
1.06 μm 150 psec laser damage study of diamond turned, diamond turned/ polished and polished metal mirrors (open access)

1.06 μm 150 psec laser damage study of diamond turned, diamond turned/ polished and polished metal mirrors

Using a well characterized 1.06 μm 150 ps glass laser pulse the damage characteristics for diamond turned, diamond turned/ polished, and polished copper and silver mirrors less than 5 cm diameter were studied. Although most samples were tested with a normal angle of incidence, some were tested at 45$sup 0$ with different linear polarization showing an increase in damage threshold for S polarization. Different damage mechanisms observed will be discussed. Laser damage is related to residual surface influences of the fabrication process. First attempts to polish diamond turned surfaces resulted in a significant decrease in laser damage threshold. The importance of including the heat of fusion in the one dimensional heat analysis of the theoretical damage threshold and how close the samples came to the theoretical damage threshold is discussed. (auth)
Date: July 24, 1975
Creator: Saito, T. T.; Milam, D.; Baker, P. & Murphy, G.
System: The UNT Digital Library
(2,2-Bipyridyl)bis(eta5-1,2,3,4,5-pentamethylcyclopentadienyl)Strontium(II) (open access)

(2,2-Bipyridyl)bis(eta5-1,2,3,4,5-pentamethylcyclopentadienyl)Strontium(II)

In the title compound, the Sr-N distances are 2.624 (3) and 2.676 (3) Angstroms. The Sr-centroid distances are 2.571 and 2.561 Angstroms. The N-C-C-N torsion angle in the bipyridine ligand is 2.2 (4){sup o}. Interestingly, the bipyridine ligand is tilted. The angle between the plane defined by Sr1, N1 and N2 and the plane defined by the 12 atoms of the bipyridine ligand is 10.7{sup o}.
Date: July 3, 2008
Creator: Kazhdan, Daniel; Kazhdan, Daniel; Hu, Yung-Jin; Kokai, Akos; Levi, Zerubba & Rozenel, Sergio
System: The UNT Digital Library
2-D Path Corrections for Local and Regional Coda Waves: A Test of Transportability (open access)

2-D Path Corrections for Local and Regional Coda Waves: A Test of Transportability

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. [2003] 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. We will compare performance of 1-D versus 2-D path corrections in a variety of regions. First, 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. Next, we will compare results for the Italian Alps using high frequency data from the University of Genoa. For Northern California, we used the same station and event distribution and compared 1-D and 2-D path …
Date: July 13, 2005
Creator: Mayeda, K M; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D S & Morasca, P
System: The UNT Digital Library
2-D Tomography With Bolometry in DIII-D (open access)

2-D Tomography With Bolometry in DIII-D

We have installed a 48-channel platinum-foil bolometer system on DIII-D achieve better spatial and temporal resolution of the radiated power in diverted discharges. Two 24-channel arrays provide complete plasma coverage with optimized views of the divertor. We have measured the divertor radiation profile for a series of radiative divertor and power balance experiments. We observe a rapid change in the magnitude and distribution of divertor radiation with heavy gas puffing. Unfolding the radiation profile with only two views requires us to treat the core and divertor radiation separately. The core radiation is fitted to a function of magnetic flux and is then subtracted from the divertor viewing chords. The divertor profile is then fit to a 2-D spline as a function of magnetic flux and poloidal angle.
Date: July 1, 1994
Creator: Leonard, A. W.; Meyer, W. H.; Geer, B.; Behne, D. M. & Hill, D. N.
System: The UNT Digital Library
3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation (open access)

3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation

The spermine-based hydroxypyridonate octadentate chelator 3,4,3-LI(1,2-HOPO) was investigated for its ability to act as an antennae that sensitizes the emission of Sm{sup III}, Eu{sup III}, and Tb{sup III} in the Visible range (Φ{sub tot} = 0.2 - 7%) and the emission of Pr{sup III}, Nd{sup III}, Sm{sup III}, and Yb{sup III} in the Near Infra-Red range, with decay times varying from 1.78 μs to 805 μs at room temperature. The particular luminescence spectroscopic properties of these lanthanide complexes formed with 3,4,3-LI(1,2-HOPO) were used to characterize their respective solution thermodynamic stabilities as well as those of the corresponding La{sup III}, Gd{sup III}, Dy{sup III}, Ho{sup III}, Er{sup III}, Tm{sup III}, and Lu{sup III} complexes. The remarkably high affinity of 3,4,3-LI(1,2-HOPO) for lanthanide metal ions and the resulting high complex stabilities (pM values ranging from 17.2 for La{sup III} to 23.1 for Yb{sup III}) constitute a necessary but not sufficient criteria to consider this octadentate ligand an optimal candidate for in vivo metal decorporation. The in vivo lanthanide complex stability and decorporation capacity of the ligand were assessed, using the radioactive isotope {sup 152}Eu as a tracer in a rodent model, which provided a direct comparison with the in vitro thermodynamic results …
Date: July 13, 2011
Creator: Sturzbecher-Hoehne, Manuel; Ng Pak Leung, Clara; Daleo, Anthony; Kullgren, Birgitta; Prigent, Anne-Laure; Shuh, David K. et al.
System: The UNT Digital Library
3-D field computation: The near-triumph of commerical codes (open access)

3-D field computation: The near-triumph of commerical codes

In recent years, more and more of those who design and analyze magnets and other devices are using commercial codes rather than developing their own. This paper considers the commercial codes and the features available with them. Other recent trends with 3-D field computation include parallel computation and visualization methods such as virtual reality systems.
Date: July 1995
Creator: Turner, L. R.
System: The UNT Digital Library
3-D Finite Element Analysis of Induction Logging in a Dipping Formation (open access)

3-D Finite Element Analysis of Induction Logging in a Dipping Formation

Electromagnetic induction by a magnetic dipole located above a dipping interface is of relevance to the petroleum well-logging industry. The problem is fully three-dimensional (3-D) when formulated as above, but reduces to an analytically tractable one-dimensional (1-D) problem when cast as a small tilted coil above a horizontal interface. The two problems are related by a simple coordinate rotation. An examination of the induced eddy currents and the electric charge accumulation at the interface help to explain the inductive and polarization effects commonly observed in induction logs from dipping geological formations. The equivalence between the 1-D and 3-D formulations of the problem enables the validation of a previously published finite element solver for 3-D controlled-source electromagnetic induction.
Date: July 20, 2000
Creator: Everett, Mark E.; Badea, Eugene A,; Shen, Liang, C.; Merchant, Gulamabbas A. & Weiss, Chester J.
System: The UNT Digital Library
3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration (open access)

3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occurring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When …
Date: July 2, 2008
Creator: Lee, Shiu-Hang; Kamae, Tuneyoshi & Ellison, Donald C.
System: The UNT Digital Library
3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution (open access)

3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution

Three-dimensional photonic lattices are engineered materials which are the photonic analogues of semiconductors. These structures were first proposed and demonstrated in the mid-to-late 1980's. However, due to fabrication difficulties, lattices active in the infrared are only just emerging. Wide ranges of structures and fabrication approaches have been investigated. The most promising approach for many potential applications is a diamond-like structure fabricated using silicon microprocessing techniques. This approach has enabled the fabrication of 3-D silicon photonic lattices active in the infrared. The structures display band gaps centered from 12{micro} down to 1.55{micro}.
Date: July 8, 1999
Creator: Fleming, J.G. & Lin, Shawn-Yu
System: The UNT Digital Library
3 MW, 110 GHz ECH system for the DIII-D tokamak (open access)

3 MW, 110 GHz ECH system for the DIII-D tokamak

To support the Advanced Tokamak (AT) operating regimes in the DIII-D tokamak, methods need to be developed to control the current and pressure profiles across the plasma discharge. In particular, AT plasmas require substantial off-axis current in contrast to normal tokamak discharges where the current peaks on-axis. An effort is under way to use Electron Cyclotron Current Drive (ECCD) as a method of sustaining the off-axis current in AT plasmas. The first step in this campaign is the installation of three megawatts of electron cyclotron heating power. This involves the installation of three rf systems operating at 110 GHz, the second harmonic resonance frequency on DIII-D, with each system generating nominally 1 MW. The three systems will use one GYCOM (Russian) gyrotron and two CPI (formerly Varian) gyrotrons, all with windowless evacuated corrugated low loss transmission lines. The first two of three 1 MW ECH systems is operating routinely at DIII-D with injected power at 110 GHz of approximately 1.5 MW with good power accountability. Transport experiments using modulated ECH have been performed confirming the power deposition location. On-axis and off-axis current drive experiments have been successfully performed with on-axis ECCD currents of 170 kA being observed.
Date: July 1998
Creator: Callis, R. W.; Lohr, J.; Ponce, D.; Harris, T. E.; O`Neill, R. C.; Remsen, D.B. et al.
System: The UNT Digital Library
3(omega) damage threshold evaluation of final optics components using Beamlet mule and off-line testing (open access)

3(omega) damage threshold evaluation of final optics components using Beamlet mule and off-line testing

A statistics-based model is being developed to predict the laser-damage-limited lifetime of UV optical components on the NIF laser. In order to provide data for the model, laser damage experiments were performed on the Beamlet laser system at LLNL. An early prototype NIF focus lens was exposed to twenty 35 1 nm pulses at an average fluence of 5 J/cm{sup 2}, 3ns. Using a high resolution optic inspection system a total of 353 damage sites was detected within the 1160 cm{sup 2} beam aperture. Through inspections of the lens before, after and, in some cases, during the campaign, pulse to pulse damage growth rates were measured for damage initiating both on the surface and at bulk inclusions. Growth rates as high as 79 {micro}m/pulse (surface diameter) were observed for damage initiating at pre-existing scratches in the surface. For most damage sites on the optic, both surface and bulk, the damage growth rate was approximately l0{micro}m/pulse. The lens was also used in Beamlet for a subsequent 1053 {micro}m/526 {micro}m campaign. The 352 {micro}m-initiated damage continued to grow during that campaign although at generally lower growth rate.
Date: July 27, 1998
Creator: Kozlowski, M. F.; Maricle, S.; Mouser, R.; Schwartz, S.; Wegner, P. & Weiland, T.
System: The UNT Digital Library
A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback (open access)

A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback

A 4.2 GS/sec. beam excitation system with accelerator synchronization and power stages is described. The system is capable of playing unique samples (32 samples/bunch) for 15,000 turns on selected bunch(es) in the SPS in syn- chronism with the injection and acceleration cycle. The purpose of the system is to excite internal modes of single-bunch vertical motion, and study the bunch dynamics in the presence of developing Electron cloud or TMCI effects. The system includes a synchronized master oscillator, SPS timing functions, an FPGA based arbitrary waveform generator, 4.2 GS/sec. D/A system and four 80W 20-1000 MHz amplifiers driving a tapered stripline pickup/kicker. A software GUI allows specification of various modulation signals, selection of bunches and turns to excite, while a remote control interface allows simple control/monitoring of the RF power stages located in the tunnel. The successful use of this system for SPS MD measurements in 2011 is a vital proof-of-principle for wideband feedback using similar functions to correct the beam motion.
Date: July 10, 2012
Creator: Fox, John
System: The UNT Digital Library
An 8-Element Fast-Neutron Double-Scatter Directional Detector. (open access)

An 8-Element Fast-Neutron Double-Scatter Directional Detector.

We have constructed a fast-neutron double-scatter spectrometer that efficiently measures the neutron spectrum and direction of a spontaneous fission source. The device consists of two planes of organic scintillators, each having an area of 125 cm{sup 2}, efficiently coupled to photomultipliers. The four scintillators in the front plane are 2 cm thick, giving almost 25% probability of detecting an incident fission-spectrum neutron at 2 MeV by proton recoil and subsequent ionization. The back plane contains four 5-cm-thick scintillators which give a 40% probability of detecting a scattered fast neutron. A recordable double-scatter event occurs when a neutron is detected in both a front plane detector and a back plane detector within an interval of 500 nanoseconds. Each double-scatter event is analyzed to determine the energy deposited in the front plane, the time of flight between detectors, and the energy deposited in the back plane. The scattering angle of each incident neutron is calculated from the ratio of the energy deposited in the first detector to the kinetic energy of the scattered neutron.
Date: July 31, 2005
Creator: Vanier, P. E. & Forman, L.
System: The UNT Digital Library
10 CFR 830.120 Criterion 10, Independent Assessment: We`re here to help you! (open access)

10 CFR 830.120 Criterion 10, Independent Assessment: We`re here to help you!

Each organization performing activities in the DOE Weapons Complex is required to have an pendent assessment function. This is consistent from DOE Order 5700.6C, Quality Assurance to 10 CFR 830-120, sometimes referred to as the Price-Anderson rule. DOE Order 5700.6C, Criterion 10 Independent Assessment requires, `` Planned and periodic independent assessments shall be conducted to measure item quality and process effectiveness and to promote improvement. The organization performing independent assessments shall have sufficient authority and freedom from the line organization to carry out its responsibilities. Persons conducting independent assessments shall be technically qualified and knowledgeable in the areas assessed.`` 10 CFR 830.120, (c) Quality assurance criteria -- (3) Assessment -- (ii) Independent Assessment requires,``Independent assessments shall be planned and conducted to measure item and service quality, to measure the adequacy of work performance, and to promote improvement. The group performing independent assessments shall have sufficient authority and freedom from the line to carry out its responsibilities. Persons conducting independent assessments shall be technically qualified and knowledgeable in the areas assessed.``
Date: July 1, 1995
Creator: Farrell, R.E.
System: The UNT Digital Library
10-kJ Status and 100-kJ Future for NIF PetaWatt Technology (open access)

10-kJ Status and 100-kJ Future for NIF PetaWatt Technology

We discuss the status of the NIF ARC, an 8-beam 10-kJ class high-energy petawatt laser, and the future upgrade path of this and similar systems to 100-kJ-class with coherent phasing of multiple apertures.
Date: July 2, 2007
Creator: Siders, C W; Crane, J K; Rushford, M C; Haefner, L C; Hernandez, J E; Dawson, J W et al.
System: The UNT Digital Library
12 GeV Upgrade Project - Cryomodule Production (open access)

12 GeV Upgrade Project - Cryomodule Production

The Thomas Jefferson National Accelerator Facility (Jefferson Lab) is producing ten 100+MV SRF cryomodules (C100) as part of the CEBAF 12 GeV Upgrade Project. Once installed, these cryomodules will become part of an integrated accelerator system upgrade that will result in doubling the energy of the CEBAF machine from 6 to 12 GeV. This paper will present a complete overview of the C100 cryomodule production process. The C100 cryomodule was designed to have the major components procured from private industry and assembled together at Jefferson Lab. In addition to measuring the integrated component performance, the performance of the individual components is verified prior to being released for production and assembly into a cryomodule. Following a comprehensive cold acceptance test of all subsystems, the completed C100 cryomodules are installed and commissioned in the CEBAF machine in preparation of accelerator operations. This overview of the cryomodule production process will include all principal performance measurements, acceptance criterion and up to date status of current activities.
Date: July 1, 2012
Creator: J. Hogan, A. Burrill, G.K. Davis, M.A. Drury, M. Wiseman
System: The UNT Digital Library
A 12 GHz RF Power Source for the CLIC Study (open access)

A 12 GHz RF Power Source for the CLIC Study

The CLIC RF frequency has been changed in 2008 from the initial 30 GHz to the European X-band 11.9942 GHz permitting beam independent power production using klystrons for CLIC accelerating structure testing. A design and fabrication contract for five klystrons at that frequency has been signed by different parties with SLAC. France (IRFU, CEA Saclay) is contributing a solid state modulator purchased in industry and specific 12 GHz RF network components to the CLIC study. RF pulses over 120 MW peak at 230 ns length will be obtained by using a novel SLED-I type pulse compression scheme designed and fabricated by IAP, Nizhny Novgorod, Russia. The X-band power test stand is being installed in the CLIC Test Facility CTF3 for independent structure and component testing in a bunker, but allowing, in a later stage, for powering RF components in the CTF3 beam lines. The design of the facility, results from commissioning of the RF power source and the expected performance of the Test Facility are reported.
Date: July 3, 2012
Creator: Schirm, Karl; Curt, Stephane; Dobert, Steffen; McMonagle, Gerard; Rossat, Ghislain; Syratchev, Igor et al.
System: The UNT Digital Library
A 14 MeV Fusion Neutron Source for Material and Blanket Development and Fission Fuel Production (open access)

A 14 MeV Fusion Neutron Source for Material and Blanket Development and Fission Fuel Production

None
Date: July 30, 2012
Creator: Simonen, T. C.; Moir, R. W.; Molvik, A. W. & Ryutov, D. D.
System: The UNT Digital Library
14 MeV neutron work at the Lawrence Livermore National Laboratory (open access)

14 MeV neutron work at the Lawrence Livermore National Laboratory

The 14 MeV neutron work at Lawrence Livermore National Laboratory (LLNL) covers two main areas of interest to this Symposium: (1) measurements and calculations of differential cross sections; and (2) integral measurements of the neutron and gamma emission spectra. In both areas a large number of materials have been studied, spanning a wide mass range (6 < A < 239), of interest to fusion and hybrid reactors. In this presentation a brief description of the experimental techniques and calculational analysis is given for each of the above areas and the measured and calculated cross sections are discussed. 28 refs., 7 figs., 3 tabs.
Date: July 1, 1985
Creator: Hansen, L. F.
System: The UNT Digital Library
A 16 Mev/Nucleon Cocktail for Heavy Ion Testing (open access)

A 16 Mev/Nucleon Cocktail for Heavy Ion Testing

This report gives the description of a new cocktail of heavy ions ranging from Z=7-36 at 16 MeV/Nucleon.
Date: July 31, 2004
Creator: McMahan, M. A.; Leitner, D.; Gimpel, T.; Morel, J.; Ninemire, B.; Siero, R. et al.
System: The UNT Digital Library