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Preparation of a 1 mg/cm{sup 2} {sup 13}C target. (open access)

Preparation of a 1 mg/cm{sup 2} {sup 13}C target.

We give a description for the production of {sup 13}C foils and the preparation of an approximately 1 mg/cm{sup 2} thick target. A recent experiment to measure the mass of {sup 36}Ca via the {sup 40}Ca({sup 4}He,{sup 8}He){sup 36}Ca reaction at the S800 magnetic spectrometer at MSU, needed a precise determination of the beam energy and calibration of the focal plane of the magnetic spectrometer in order to achieve the most accurate value for the {sup 36}Ca mass. The 1 mg/cm{sup 2} {sup 13}C target was essential for these purposes. Target performance along with some preliminary results will also be discussed.
Date: November 18, 1998
Creator: Greene, J. P.
System: The UNT Digital Library
Development of niobium spoke cavities for a superconducting light-ion Linac. (open access)

Development of niobium spoke cavities for a superconducting light-ion Linac.

This paper reports the development of 350 MHz niobium superconducting cavities for the velocity range 0.2< v/c <0.6. Such cavities could be used to form a linac of exceptional flexibility, capable of efficiently accelerating beams of either protons, deuterons, or any of a wide range of light ions, at intensities sufficient for a production beam for a radioactive beam facility. Results of numerical modeling for several resonator geometries are presented. The design and construction status of prototype niobium cavities is discussed.
Date: November 18, 1998
Creator: Shepard, K. W.
System: The UNT Digital Library
SMQIE: Challenges associated with a low frequency charge integrator and encoder for the CDF II Calorimeter (open access)

SMQIE: Challenges associated with a low frequency charge integrator and encoder for the CDF II Calorimeter

The SMQIE is the newest member of the QIE family of integrated circuits. It has been developed specifically for the Shower Max Detector upgrade of the CDF Plug and Central Calorimeters at Fermilab. Like its predecessors, it converts charges over a wide dynamic range with a variable resolution. Unlike its predecessors it contains its own Flash, trigger delay pipeline and buffer area. Furthermore, it operates both at a lower frequency and with only a simple 5-volt power supply. The simultaneous requirements of low frequency and reduced voltage force the front end into a low current, high impedance regime. Specialized circuitry is necessary to prevent charge slopped-over into subsequent time slices. The considerable amount of digital circuitry monolithic with the analog front end makes for a noisy substrate. Specialized circuitry and layout techniques are necessary to keep this chip from being noise-limited. The final design is a two-channel single-ended Charge Integrator and Encoder (QIE) that operates at a frequency of 7.6MHz with a least significant bit resolution of 15 fC in its lowest range.
Date: November 18, 1999
Creator: J. Hoff, G. Drake, A. Byon-Wagner, G. Foster and M. Lindgren
System: The UNT Digital Library
Recent developments in theories of pion production in nucleon-nucleon collisions. (open access)

Recent developments in theories of pion production in nucleon-nucleon collisions.

Recent developments in theories of pion production in nucleon-nucleon collisions are reviewed.
Date: November 18, 1998
Creator: Lee, T. S. H.
System: The UNT Digital Library
Vortex melting and the liquid state in YBa{sub 2}Cu{sub 3}O{sub x}. (open access)

Vortex melting and the liquid state in YBa{sub 2}Cu{sub 3}O{sub x}.

The experimental vortex phase diagram of YBa{sub 2}Cu{sub 3}O{sub x} is reviewed, with emphasis on first order vortex melting, the upper and lower critical points on the melting line, and the effect of disorder arising from twin boundary and point defect pinning.
Date: November 18, 1998
Creator: Crabtree, G. W.
System: The UNT Digital Library
Rotating liquid blanket with no first wall for fusion reactors (open access)

Rotating liquid blanket with no first wall for fusion reactors

A toroidal vortex of liquid FLiBe (LiF + BeF/sub 2/) is suggested for the blanket of a fusion reactor. Because this reactor chamber has no solid first wall, it might avoid many of the problems that accompany conventional blanket design. The liquid blanket is sustained by nozzles that inject a continuous layer of cool liquid on the inner surface. A second set of nozzles sends a stream of droplets across the diverted scrape-off layer or edge plasma to carry its heat away. The feasibility issues of most importance are judged to be avoiding turbulent breakup of the vortex and preventing too much contamination of the plasma by the evaporating FliBe. 7 refs., 5 figs., 1 tabs.
Date: November 18, 1988
Creator: Moir, Ralph W.
System: The UNT Digital Library
Report on the experience with the Supervisory Control and Diagnostics System (SCDS) of MFTF-B (open access)

Report on the experience with the Supervisory Control and Diagnostics System (SCDS) of MFTF-B

The Supervisory Control and Diagnostics System (SCDS) of MFTF is a multiprocessor computer system using graphics oriented displays with touch sensitive panels as the primary operator interface. Late in the calendar year 1981 the system was used to control an integrated test of the vacuum vessel, vacuum system, cryogenics system and the superconducting magnet of MFTF. Since the completion of those tests and starting in early calendar 1983 the system has been used for control of the neutral beam test facility at LLNL. This paper presents a short overview of SCDS for the purpose of orientation and then proceeds to describe the difficulties encountered in these preliminary encounters with reality. The band-aids used to hold things together as disaster threatened as well as the long-term solutions to the problems will be discussed. Finally, we will present some comments on system costs and management philosophy.
Date: November 18, 1983
Creator: Wyman, R.H.
System: The UNT Digital Library
Texas WASP Honored by Sen. Hutchison in Dallas Ceremony (open access)

Texas WASP Honored by Sen. Hutchison in Dallas Ceremony

Printed online article from Air Force Print News Today about the history of the Women Airforce Service Pilots and how Senator Hutchison honored the women with a bill awarding the Congressional Gold Medal.
Date: November 18, 2009
Creator: Hickerson, Katie
System: The Portal to Texas History
Interagency Advanced Power Group Steering Group meeting minutes (open access)

Interagency Advanced Power Group Steering Group meeting minutes

This document contains presentation overviews and viewgraphs from a meeting military personnel on the subject of power generation and distribution systems for military applications. Mission analysis and directional plans were given for each working group (chemical, mechanical, electrical, nuclear, solar and systems). Attendees represented the US Air Force, Army, Navy, and NASA.
Date: November 18, 1992
Creator: unknown
System: The UNT Digital Library
X-Ray Absorption Characterization of Diesel Exhaust Particulates (open access)

X-Ray Absorption Characterization of Diesel Exhaust Particulates

We have characterized particulates from a 1993 11.1 Detroit Diesel Series 60 engine with electronic unit injectors operated using fuels with and without methylcyclopentadienyl manganese tricarbonyl (MMT) and overbased calcium sulfonate added. X-ray photoabsorption (XAS) spectroscopy was used to characterize the diesel particulates. Results reveal a mixture of primarily Mn-phosphate with some Mn-oxide, and Ca-sulfate on the surface of the filtered particulates from the diesel engine.
Date: November 18, 1999
Creator: Nelson, A J; Ferreira, J L; Reynolds, J G & Roos, J W
System: The UNT Digital Library
An R and D Program for Targetry and Capture at a Neutrino Factory Muon Collider Source. (open access)

An R and D Program for Targetry and Capture at a Neutrino Factory Muon Collider Source.

The need for intense muon beams for muon colliders and for neutrino factories based on muon storage rings leads to a concept of 1-4 MW proton beams incident on a moving target that is inside a 20-T solenoid magnet, with a mercury jet as a preferred example. Novel technical issues for such a system include disruption of the mercury jet by the proton beam and distortion of the jet on entering the solenoid, as well as more conventional issues of materials lifetime and handling of activated materials in an intense radiation environment. As part of the R&D program of the Neutrino Factory and Muon Collider Collaboration, an R&D effort related to targetry is being performed within the context of experiment E951 at Brookhaven National Laboratory, first results of which are reported here.
Date: November 18, 2003
Creator: Hassenein, A.
System: The UNT Digital Library
Determination of effective axion masses in the helium-3 buffer of CAST (open access)

Determination of effective axion masses in the helium-3 buffer of CAST

The CERN Axion Solar Telescope (CAST) is a ground based experiment located in Geneva (Switzerland) searching for axions coming from the Sun. Axions, hypothetical particles that not only could solve the strong CP problem but also be one of the favored candidates for dark matter, can be produced in the core of the Sun via the Primakoff effect. They can be reconverted into X-ray photons on Earth in the presence of strong electromagnetic fields. In order to look for axions, CAST points a decommissioned LHC prototype dipole magnet with different X-ray detectors installed in both ends of the magnet towards the Sun. The analysis of the data acquired during the first phase of the experiment yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV/c{sup 2}. During the second phase, CAST extends its mass sensitivity by tuning the electron density present in the magnetic field region. Injecting precise amounts of helium gas has enabled CAST to look for axion masses up to 1.2 eV/c{sup 2}. This paper studies the determination of the effective axion masses scanned at CAST during its second phase. The use of a helium gas buffer at …
Date: November 18, 2011
Creator: Ruz, J
System: The UNT Digital Library
Role of Standard Demand Response Signals for Advanced Automated Aggregation (open access)

Role of Standard Demand Response Signals for Advanced Automated Aggregation

Emerging standards such as OpenADR enable Demand Response (DR) Resources to interact directly with Utilities and Independent System Operators to allow their facility automation equipment to respond to a variety of DR signals ranging from day ahead to real time ancillary services. In addition, there are Aggregators in today’s markets who are capable of bringing together collections of aggregated DR assets and selling them to the grid as a single resource. However, in most cases these aggregated resources are not automated and when they are, they typically use proprietary technologies. There is a need for a framework for dealing with aggregated resources that supports the following requirements: • Allows demand-side resources to participate in multiple DR markets ranging from wholesale ancillary services to retail tariffs without being completely committed to a single entity like an Aggregator; • Allow aggregated groups of demand-side resources to be formed in an ad hoc fashion to address specific grid-side issues and support the optimization of the collective response of an aggregated group along a number of different dimensions. This is important in order to taylor the aggregated performance envelope to the needs to of the grid; • Allow aggregated groups to be formed in …
Date: November 18, 2011
Creator: Laboratory, Lawrence Berkeley National & Kiliccote, Sila
System: The UNT Digital Library
Nanostructured Energetci Matreials with sol-gel Chemistry (open access)

Nanostructured Energetci Matreials with sol-gel Chemistry

The utilization of nanomaterials in the synthesis and processing of energetic materials (i.e., pyrotechnics, explosives, and propellants) is a relatively new area of science and technology. Previous energetic nanomaterials have displayed new and potentially beneficial properties, relative to their conventional analogs. Unfortunately some of the energetic nanomaterials are difficult and or expensive to produce. At LLNL we are studying the application of sol-gel chemical methodology to the synthesis of energetic nanomaterials components and their formulation into energetic nanocomposites. Here sol-gel synthesis and formulation techniques are used to prepare Fe{sub 2}O{sub 3}/Al pyrotechnic nanocomposites. The preliminary characterization of their thermal properties and the degree of mixing between fuel and oxidizer phases is contrasted with that of a conventional pyrotechnic mixture.
Date: November 18, 2003
Creator: Gash, A.; Satcher, J.; Simpson, R. & Clapsaddle, B.
System: The UNT Digital Library
RFOFO COOLING RING: SIMULATION RESULTS. (open access)

RFOFO COOLING RING: SIMULATION RESULTS.

Practical cooling rings could lead to lower cost or improved performance in neutrino factory or muon collider designs, The ring modeled here uses realistic 3-dimensional fields and includes such ''real-world'' effects as windows on the absorbers and RF cavities and leaving empty lattice cells for injection and extraction. The ring increases the density of muons in a fixed acceptance volume by a factor of 4.2.
Date: November 18, 2003
Creator: BERG,J. S. FERNOW,R. C. GALLARDO,J. C. PALMER,R. B.
System: The UNT Digital Library
Calculation of Shock Hugoniot Curves of Precompressed Liquid Deuterium (open access)

Calculation of Shock Hugoniot Curves of Precompressed Liquid Deuterium

Path integral Monte Carlo simulations have been used to study deuterium at high pressure and temperature. The equation of state has been derived in the temperature and density region of 10,000 {le} T {le} 1,000,000 and 0.6 {le} {rho} {le} 2.5 g cm{sup -3}. A series of shock Hugoniot curves is computed for different initial compressions in order to compare with current and future shock wave experiments using liquid deuterium samples precompressed in diamond anvil cells.
Date: November 18, 2002
Creator: Militzer, B
System: The UNT Digital Library
Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials (open access)

Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due …
Date: November 18, 2003
Creator: Gash, A. E.; Pantoya, M. L.; Satcher, J. H. Jr.; Zhao, L.; Shea, K. J.; Simpson, R. L. et al.
System: The UNT Digital Library
Overview of Neutrino Factory Simulations. (open access)

Overview of Neutrino Factory Simulations.

Recent simulations have shown that muon cooling rings can effectively reduce both longitudinal and transverse emittance. The muon collaboration is investigating several varieties of muon cooling rings. This study looks at the first of these ring cooling scenarios that was proposed by V. Balbekov. This simulation of this ring shows significant cooling in the hard-edge field approximation. We discuss the status of using realistic fields in the tetra simulation.
Date: November 18, 2003
Creator: Fernow, R.C.
System: The UNT Digital Library
X-ray Emission Spectroscopy in Magnetic 3d-Transition Metals (open access)

X-ray Emission Spectroscopy in Magnetic 3d-Transition Metals

The application of high pressure affects the band structure and magnetic interactions in solids by modifying nearest-neighbor distances and interatomic potentials. While all materials experience electronic changes with increasing pressure, spin polarized, strongly electron correlated materials are expected to undergo the most dramatic transformations. In such materials, (d and f-electron metals and compounds), applied pressure reduces the strength of on-site correlations, leading to increased electron delocalization and, eventually, to loss of its magnetism. In this ongoing project, we study the electronic and magnetic properties of Group VIII, 3d (Fe, Co and Ni) magnetic transition metals and their compounds at high pressures. The high-pressure properties of magnetic 3d-transition metals and compounds have been studied extensively over the years, because of iron being a major constituent of the Earth's core and its relevance to the planetary modeling to understand the chemical composition, internal structure, and geomagnetism. However, the fundamental scientific interest in the high-pressure properties of magnetic 3d-electron systems extends well beyond the geophysical applications to include the electron correlation-driven physics. The role of magnetic interactions in the stabilization of the ''non-standard'' ambient pressure structures of Fe, Co and Ni is still incompletely understood. Theoretical studies have predicted (and high pressure experiments …
Date: November 18, 2003
Creator: Iota, V.; Park, J.; Baer, B.; Yoo, C. & Shen, G.
System: The UNT Digital Library
Laser Coupling to Reduced-Scale Targets at the Early Light Program of the National Ignition Facility (open access)

Laser Coupling to Reduced-Scale Targets at the Early Light Program of the National Ignition Facility

A platform for analysis of material properties under extreme conditions, where a sample is bathed in radiation with a high temperature, is under development. This hot environment is produced with a laser by depositing maximum energy into a small, high-Z can. Such targets were recently included in an experimental campaign using the first four of the 192 beams of the National Ignition Facility, under construction at the University of California Lawrence Livermore National Laboratory. These targets demonstrate good laser coupling, reaching a radiation temperature of 340 eV. In addition, there is a unique wavelength dependence of the Raman backscattered light that is consistent with Brillouin backscatter of Raman forward scatter [A. B. Langdon and D. E. Hinkel, Physical Review Letters 89, 015003 (2002)]. Finally, novel diagnostic capabilities indicate that 20% of the direct backscatter from these reduced-scale targets is in the polarization orthogonal to that of the incident light.
Date: November 18, 2004
Creator: Hinkel, D. E.; Schneider, M. B.; Baldis, H. A.; Bower, D.; Campbell, K. M.; Celeste, J. R. et al.
System: The UNT Digital Library
Explosive Chemistry: Simulating the Chemistry of Energetic Materials at Extreme Conditions (open access)

Explosive Chemistry: Simulating the Chemistry of Energetic Materials at Extreme Conditions

In the brief instant of a high-explosive detonation, the shock wave produces a pressure 500,000 times that of the Earth's atmosphere, the detonation wave travels as fast as 10 kilometers per second, and internal temperatures soar up to 5,500 Kelvin. As the shock propagates through the energetic material, the rapid heating coupled with compression that results in almost 30% volume reduction, initiate complex chemical reactions. A dense, highly reactive supercritical fluid is established behind the propagating detonation front. Energy release from the exothermic chemical reactions serve in turn to drive and sustain the detonation process until complete reactivity is reached. Several experimental results suggest the existence of strong correlations between the applied mechanical stress and shocks, the local heterogeneity and defects (dislocations, vacancies, cracks, impurities, etc.), and the onset of chemical reactions. The reaction chemistry of energetic materials at high pressure and temperature is, therefore, of considerable importance in understanding processes that these materials experience under impact and detonation conditions. Chemical decomposition models are critical ingredients in order to predict, among other things, the measured times to explosion and the conditions for ignition of hot spots, localized regions of highly concentrated energy associated with defects. To date, chemical kinetic rates …
Date: November 18, 2003
Creator: Reed, E J; Manaa, M R & Fried, L E
System: The UNT Digital Library
Dislocation Interactions with Voids and Helium Bubbles in FCC Metals (open access)

Dislocation Interactions with Voids and Helium Bubbles in FCC Metals

The formation of a high number density of helium bubbles in FCC metals irradiated within the fusion energy environment is well established. Yet, the role of helium bubbles in radiation hardening and mechanical property degradation of these steels remains an outstanding issue. In this paper, we present the results of a combined molecular dynamics simulation and in-situ straining transmission electron microscopy study, which investigates the interaction mechanisms between glissile dislocations and nanometer-sized helium bubbles. The molecular dynamics simulations, which directly account for dislocation core effects through semi-empirical interatomic potentials, provide fundamental insight into the effect of helium bubble size and internal gas pressure on the dislocation/bubble interaction and bypass mechanisms. The combination of simulation and in-situ straining experiments provides a powerful approach to determine the atomic to microscopic mechanisms of dislocation-helium bubble interactions, which govern the mechanical response of metals irradiated within the fusion environment.
Date: November 18, 2003
Creator: Robertson, I.; Robach, J.; Wirth, B. & Young, J.
System: The UNT Digital Library
Development of a Microcantilever-Based Pathogen Detector (open access)

Development of a Microcantilever-Based Pathogen Detector

The ability to detect small amounts of materials, especially whole organisms, is important for medical diagnostics and national security issues. Engineered micro-mechanical systems can serve as multifunctional, highly sensitive, real time, immunospecific biological detectors under certain circumstances. We present qualitative detection of specific Salmonella strains using a functionalized silicon nitride microcantilever. Detection is achieved due to differential surface stress on the cantilever surface in-situ. Scanning electron micrographs indicate that less than 25 adsorbed bacteria are required for detection.
Date: November 18, 2002
Creator: Weeks, B. L.; Camarero, J.; Noy, A.; Miller, A. E. & De Yoreo, J. J.
System: The UNT Digital Library
Serum Protein Profile Alterations in Hemodialysis Patients (open access)

Serum Protein Profile Alterations in Hemodialysis Patients

Background: Serum protein profiling patterns can reflect the pathological state of a patient and therefore may be useful for clinical diagnostics. Here, we present results from a pilot study of proteomic expression patterns in hemodialysis patients designed to evaluate the range of serum proteomic alterations in this population. Methods: Surface-Enhanced Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SELDI-TOFMS) was used to analyze serum obtained from patients on periodic hemodialysis treatment and healthy controls. Serum samples from patients and controls were first fractionated into six eluants on a strong anion exchange column, followed by application to four array chemistries representing cation exchange, anion exchange, metal affinity and hydrophobic surfaces. A total of 144 SELDI-TOF-MS spectra were obtained from each serum sample. Results: The overall profiles of the patient and control samples were consistent and reproducible. However, 30 well-defined protein differences were observed; 15 proteins were elevated and 15 were decreased in patients compared to controls. Serum from one patient exhibited novel protein peaks suggesting possible additional changes due to a secondary disease process. Conclusion: SELDI-TOF-MS demonstrated dramatic serum protein profile differences between patients and controls. Similarity in protein profiles among dialysis patients suggests that patient physiological responses to end-stage renal disease and/or dialysis …
Date: November 18, 2003
Creator: Murphy, G. A.; Davies, R. W.; Choi, M. W.; Perkins, J.; Turteltaub, K. W.; McCutchen-Maloney, S. L. et al.
System: The UNT Digital Library