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Optical Properties of Epitaxial Plt Thin Films

Description: Metalorganic chemical vapor deposition was used to prepare epitaxial or highly oriented PLT (Pb{sub 1-x}La{sub x}TiO{sub 3}) thin films with x = 0.21-0.34. The growth of PLT films resulted in 3-D epitaxial heterostructures on a (100) surface of both MgO and KTaO{sub 3} substrates. The PLT film grown on a KTaO{sub 3} (100) substrate has a significantly lower minimum channeling yield compared to that grown on the MgO (100) substrate because of the smaller lattice mismatch associated with KTaO{sub… more
Date: January 1, 1996
Creator: Kim, Y.; Erbil, A.; Boatner, L. A.; Steingart, L.; Mensah, T. & Hiamang, S.
Partner: UNT Libraries Government Documents Department
open access

Single-Point Diamond Turning of Lead Indium Phosphate Glass

Description: The development of the ability to routinely machine glass materials to optical tolerances is highly desirable and, in particular, could provide new degrees of control over the precise shape of complex and unusual optical surfaces. Of particular interest in this regard is the formation of non-spherical shapes where there is a need to fabricate both inexpensive, low-precision optics as well as specialized high-precision aspheric components. This work describes the initial feasibility tests of the… more
Date: August 1, 1996
Creator: Allison, S. W.; Cunningham, J. P.; Rajic, S.; Boatner, L. A. & Sales, B. C.
Partner: UNT Libraries Government Documents Department
open access

An Examination of Sandia`S Phenomenological Computer Codes and the Use of Intelligent Searching in Risk Assessments

Description: Because many of the phenomenologically based codes used to support risk assessments require lone execution times, it is important to have a rationally based means for optimizing the choice of parameter values that are input to the code calculations. For this reason, we have developed a method for intelligently searching the space of parameter values to deduce, with as few computations as possible, the values that are most likely to lead to high risk. We have applied the method to a problem invo… more
Date: July 1, 1996
Creator: Benjamin, A. S.
Partner: UNT Libraries Government Documents Department
open access

Identification and quantification of phases formed during the processing of (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}/Ag composite conductors

Description: Scanning electron microscopy, energy dispersive x-ray analysis, (including x-ray dot mapping), x-ray diffraction and computer based image analysis have been used to study non-superconducting secondary phases that evolve during the processing of (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}/Ag composite superconductors. These investigations have provided new information and insights about specific alkaline earth cuprates (AECs) and lead-rich phases. We can conclusively identify (Ca,Sr){sub 2… more
Date: August 1, 1996
Creator: Merchant, N. N.; Fischer, A. K.; Maroni, V. A.; Carter, W. L. & Parrella, R. D.
Partner: UNT Libraries Government Documents Department
open access

Trace metal transformation in gasification

Description: The Energy & Environmental Research Center (EERC) is carrying out an investigation that will provide methods to predict the fate of selected trace elements in integrated gasification combined cycle (IGCC) and integrated gasification fuel cell (IGFC) systems to aid in the development of methods to control the emission of trace elements determined to be air toxics. The goal of this project is to identify the effects of critical chemical and physical transformations associated with trace element b… more
Date: December 31, 1996
Creator: Benson, Steven A.; Erickson, Thomas A.; Zygarlicke, Christopher J.; O'Keefe, Cathy A.; Katrinak, Karen A.; Allen, Sean E. et al.
Partner: UNT Libraries Government Documents Department
open access

Salt-occluded zeolite waste forms: Crystal structures and transformability

Description: Neutron diffraction studies of salt-occluded zeolite and zeolite/glass composite samples, simulating nuclear waste forms loaded with fission products, have revealed complex structures, with cations assuming the dual roles of charge compensation and occlusion (cluster formation). These clusters roughly fill the 6--8 {angstrom} diameter pores of the zeolites. Samples are prepared by equilibrating zeolite-A with complex molten Li, K, Cs, Sr, Ba, Y chloride salts, with compositions representative o… more
Date: December 31, 1996
Creator: Richardson, J. W. Jr.
Partner: UNT Libraries Government Documents Department
open access

A quantum mechanical investigation of positively charged defects in SiO{sub 2} thin film devices

Description: Ab initio Hartree-Fock and second-order Moeller-Plesset theory calculations have been performed to investigate the stability of triply-coordinated O{sup +} centers in the Si-O-Si network of amorphous SiO{sub 2}. The calculations reveal that the H{sup +} ion binds with a bridging O center to form a very stable (D{sub e} > 6 eV) trivalent O complex. Capture of an electron by the positively charged protonated complex, however, is predicted to immediately lead to the dissociation of the O-H bond. A… more
Date: December 31, 1996
Creator: Ferreira, A.M.; Karna, S.P. & Brothers, C.P.
Partner: UNT Libraries Government Documents Department
open access

Effects of heavy-ion irradiation on microstructure of V-4Cr-4Ti alloy at moderate temperatures

Description: V-4Cr-4Ti is promising for first-wall and structural applications in magnetic fusion reactors. Fast neutron sources were used to evaluate postirradiation properties of fusion candidate materials, but FFTF and EBR-II have been shutdown. Under these circumstances, heavy-ion irradiation is an attractive alternative. We used 3-MeV V{sup +} and 4.5-MeV Ni{sup 2+} ions to investigate effects of irradiation on microstructure of V-4Cr-4Ti at 200-420 C. This paper report results of ion irradiation exper… more
Date: December 1, 1996
Creator: Gazda, J.; Chung, H. M.; Loomis, B. A. & Meshii, M.
Partner: UNT Libraries Government Documents Department
open access

Radiographic techniques in the Explosive Component Facility at Sandia National Labs

Description: ECF is a state of the art facility for design and testing of energetic materials and components. Two key elements are the flash x-ray machines: a 6-head 150 keV, and a 6-head 300-keV instrument. The 150 keV system was used to study the action and reaction of a linear shaped charge (LSC) while submerged in water; the submerged samples were viewed from the top to capture the interaction of one piece with another piece nearby. Each LSC was covered by separate rubber coverings and affixed to a comp… more
Date: October 1, 1996
Creator: Lanoue, J.
Partner: UNT Libraries Government Documents Department
open access

Recent advances in phosphate laser glasses for high power applications

Description: Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bu… more
Date: May 14, 1996
Creator: Campbell, J.H.
Partner: UNT Libraries Government Documents Department
open access

Few-valence-particle excitations around doubly magic {sup 132}Sn

Description: Prompt {gamma}-ray cascades in neutron-rich nuclei around doubly-magic {sup 132}Sn have been studied using a {sup 248}Cm fission source. Yrast states located in the N = 82 isotones {sup 134}Te and {sup 135}I are interpreted as valence proton and neutron particle-hole core excitations with the help of shell model calculations employing empirical nucleon-nucleon interactions from both {sup 132}Sn and {sup 208}Pb regions.
Date: November 1, 1996
Creator: Daly, P. J.; Zhang, C. T. & Bhattacharyya, P.
Partner: UNT Libraries Government Documents Department
open access

BNL-AGS complex as a spallation target test-bed

Description: The Brookhaven National Laboratory-Alternating Gradient Synchrotron (BNL-AGS) accelerates protons for high energy physics experiments up to a maximum energy of 24 GeV. The BNL-AGS complex consists of a LINAC (200 MeV), which feeds into a Booster synchrotron (1.5 GeV), and finally the main AGS ring (24 GeV). The Booster has a quarter of the AGS circumference, and thus four Booster pulses can be stacked into the AGS for acceleration up to the maximum desired energy In principle, the AGS can deliv… more
Date: October 1, 1996
Creator: Ludewig, H.; Axe, J.; Hastings, J.; Roser, T.; Todosow, M. & Schaeffer, M.
Partner: UNT Libraries Government Documents Department
open access

Portable sensor for hazardous waste

Description: We are part-way through the second phase of a 4-year program designed to develop a portable monitor for sensitive hazardous waste detection. The ultimate goal of the program is to develop our concept to the prototype instrument level. Our monitor will be a compact, portable instrument that will allow real-time, in situ, monitoring of hazardous wastes. This instrument will be able to provide the means for rapid field screening of hazardous waste sites to map the areas of greatest contamination. … more
Date: December 31, 1996
Creator: Piper, L. G.; Hunter, A. J. R.; Fraser, M. E. & Davis, S. J.
Partner: UNT Libraries Government Documents Department
open access

Beamline stability measurements with a stretched wire system in the FFTB

Description: Beamline stability is of great importance for future linear colliders where tolerances generally are in the micron to sub-micron range. A stretched wire system in the sealed FFTB tunnel at SLAC was used to monitor beamline motion with a sub-micron resolution. In future linear colliders low frequency changes of the beamline alignment (< 0.1 Hz) lead to untolerable quasistatical misalignments and betatron oscillations. Since it requires time to correct those errors, it is very important to determ… more
Date: September 1, 1996
Creator: Assmann, R.; Salsberg, C. & Montag, C.
Partner: UNT Libraries Government Documents Department
open access

A CMOS variable gain amplifier for PHENIX electromagnetic calorimeter and RICH energy measurements

Description: A variable gain amplifier (VGA) has been developed equalizing the gains of integrating amplifier channels used with multiple photomultiplier tubes operating from common high-voltage supplies. The PHENIX lead-scintillator electromagnetic calorimeter will operate in that manner, and gain equalization is needed to preserve the dynamic range of the analog memory and ADC following the integrating amplifier. The VGA is also needed for matching energy channel gains prior to forming analog sums for tri… more
Date: December 31, 1996
Creator: Wintenberg, A. L.; Simpson, M. L.; Young, G. R.; Palmer, R. L.; Moscone, C. G. & Jackson, R. G.
Partner: UNT Libraries Government Documents Department
open access

Proceedings from a Workshop on Ecological Carrying Capacity of Salmonids in the Columbia River Basin : Measure 7.1A of the Northwest Power Planning Council`s 1994 Fish and Wildlife Program : Report 3 of 4, Final Report.

Description: This report contains the proceedings of a workshop held during 1995 in Portland, Oregon. The objective of the workshop was to assemble a group of experts that could help us define carrying capacity for Columbia River Basin salmonids. The workshop was one activity designed to answer the questions asked in Measure 7.1A of the Council`s Fish and Wildlife Program. Based, in part, on the information we learned during the workshop we concluded that the approach inherent in 7.1A will not increase unde… more
Date: May 1996
Creator: Johnson, Gary E.; Neitzel, D. A. & Mavros, William V.
Partner: UNT Libraries Government Documents Department
open access

Fabrication and characterization of (Bi,Pb)-Sr-Ca-Cu-O (2223) bars

Description: Bulk bars for current lead applications were fabricated from (Bi,Pb)- Sr-Ca-Cu-O (Bi-2223) for low thermal conductivity and high critical current. Bars measuring 17.8 cm in length were made by uniaxially pressing Bi-2223 powder of controlled (1.7/0.34)223 and (1.8/0.4)223 phase composition. The bulk bars were densified by subjecting them to a schedule of alternate liquid-phase sintering and cold isostatic pressing. Liquid phase sintering temperatures were optimized from differential thermal ana… more
Date: August 1996
Creator: Chudzik, M. P.; Polzin, B. J.; Thayer, R.; Picciolo, J. J.; Fisher, B. L. & Lanagan, M. T.
Partner: UNT Libraries Government Documents Department
open access

Observation of the single step links of the yrast superdeformed band in {sup 194}Pb

Description: The EUROGAM array has been used to investigate the decay out of the yrast superdeformed (SD) band in {sup 194}Pb. Eigth single step decays from the lowest observed SD states to low-lying states at normal deformation (ND) have been identified. From this observation, the excitation energy (4877 {plus_minus} 1.5 keV) and the spin (6+) of the lowest observed SD state in {sup 194}Pb are established.
Date: December 1, 1996
Creator: Hannachi, F.; Lopez-Martens, A. & Schueck, C.
Partner: UNT Libraries Government Documents Department
open access

Emittance growth of a short electron bunch in circular motion

Description: A short electron bunch undergoing circular motion produces space-charge forces that do not decrease with increasing bunch energy, unlike those induced by straight-line motion. These energy-independent forces can be separated into a noninertial space-charge force and a coherent synchrotron radiation force. These forces result in an energy spread in the bunch, and can lead to a potentially large emittance growth. These effects can take place in both (1) bunch compression systems used to increase … more
Date: September 1996
Creator: Carlsten, B. E. & Goldstein, J. C.
Partner: UNT Libraries Government Documents Department
open access

Status report of a high luminosity muon collider and future research and development plans

Description: Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV (c-of-m) high luminosity {mu}{sup +}{mu}{sup -} colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acce… more
Date: November 1996
Creator: Palmer, R. B.; Tollestrup, A. & Sessler, A.
Partner: UNT Libraries Government Documents Department
open access

Voltage shifts and defect-dipoles in ferroelectric capacitors

Description: We review the processes and mechanisms by which voltage offsets occur in the hysteresis loop of ferroelectric materials. Simply stated, voltage shifts arise from near-interfacial charge trapping in the ferroelectric. We show that the impetus behind voltage shifts in ferroelectric capacitors is the net polarization, with the net polarization being determined by the perovskite and the aligned defect-dipole components. Some common defect-dipoles in the PZT system are lead vacancy-oxygen vacancy co… more
Date: December 1, 1996
Creator: Warren, W.L.; Pike, G.E. & Dimos, D.
Partner: UNT Libraries Government Documents Department
open access

Increased emphasis on toxics control in oil and gas industry NPDES permits

Description: The 1987 amendments to the Clean Water Act emphasized stricter control of toxics in wastewater discharges. Although state and U.S. Environmental Protection Agency permit writers have had the authority to incorporate strict water quality-based controls in permits, they did not widely use this authority in the past. However, general permits proposed in the past year by Region VI for discharges into the territorial seas of Louisiana and by Region X for coastal and offshore discharges in Alaska are… more
Date: October 1, 1996
Creator: Veil, J.A.
Partner: UNT Libraries Government Documents Department
open access

Spallation neutron production measurements

Description: Measurements of neutron production by proton bombardment of range- thick targets of Pb and W at 0.8, 1.0, 1.2, and 1.4 GeV were made for comparison with calculations based on code LAHET for neutrons with E{sub n}>20 MeV and code MCNP for E{sub n}{le}20 MeV and also to compare with each of two prior experiments dating from about 1965.
Date: October 1, 1996
Creator: Zucker, M. S.; Vanier, P. E.; von Wimmersperg, U.; Mughabghab, S. F.; Schmidt, E. & Tsoupas, N.
Partner: UNT Libraries Government Documents Department
open access

Diagnostics and data fusion of robotic sensors

Description: Robotic systems for remediation of hazardous waste sites must be highly reliable to avoid equipment failures and subsequent possible exposure of personnel to hazardous environments. Safe, efficient cleanup operations also require accurate, complete knowledge of the task space. This paper presents progress made on a 18 month program to meet these needs. To enhance robot reliability, a conceptual design of a monitoring and diagnostic system is being developed to predict the onset of mechanical fa… more
Date: December 31, 1996
Creator: Dhar, M.; Bardsley, S; Cowper, L.; Hamm, R.; Jammu, V. & Wagner, J.
Partner: UNT Libraries Government Documents Department
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