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Mechanisms of Protein and Virus Crystal Growth: An Atomic Force Microscopy Study of Canavalin Crystallization (open access)

Mechanisms of Protein and Virus Crystal Growth: An Atomic Force Microscopy Study of Canavalin Crystallization

The evolution of surface morphology and step dynamics during growth of single crystals of the protein Canavalin and of the cubic satellite tobacco mosaic virus crystals (STMV) have been investigated by in situ atomic force microscopy. These two crystals were observed to grow by very different mechanisms. Growth of Canavalin occurs on complex vicinal hillocks formed by multiple, independently acting screw dislocations. Small cluster were observed on the terraces. STMV on the other hand, was observed to grow by 2D nucleation of islands. No dislocations were found on the crystal. The results are used to determine the growth mechanisms and estimate fundamental materials parameters. The images also illustrate the important mechanism of defect incorporation and provide insight to the processes that limit the growth rate and uniformity of these crystals.
Date: March 10, 1995
Creator: Land, T. A.; De Yoreo, J. J.; Malkin, A. J.; Kutznesov, Y. G. & McPherson, A.
System: The UNT Digital Library
The SHARP scramjet launcher (open access)

The SHARP scramjet launcher

The worlds largest light gas gun at SHARP (Super High Altitude Research Project) is completed and in the past year has launched 9 scramjets. Typical masses and velocities are 5.9 kg at 2.8 km/sec.and 4.4 kg at 3.1 km/sec. In so doing SHARP launched the first fully functioning, hydrogen burning scramjet at mach 8. The SHARP launcher is unique in having a 4 inch diameter and 155 foot-long barrel. This enables lower acceleration launches than any other system. In addition the facility can deliver high energy projectiles to targets in the open air without having to contain the impact fragments. This allows one to track lethality test debris for several thousand feet.
Date: January 10, 1995
Creator: Cartland, H.; Fiske, P.; Greenwood, R.; Hargiss, D.; Heston, P.; Hinsey, N. et al.
System: The UNT Digital Library
Growth morphology of vicinal hillocks on the (101) face of KH{sub 2}PO{sub 4}: Evidence of surface diffusion (open access)

Growth morphology of vicinal hillocks on the (101) face of KH{sub 2}PO{sub 4}: Evidence of surface diffusion

The growth morphologies of vicinal hillocks on KH{sub 2}PO{sub 4} (101) surfaces have been investigated using atomic force microscopy. Both 2D and spiral dislocation growth hillocks are observed on the same crystal surface at supersaturations of {approximately}5%. Growth occurs on monomolecular 5 {Angstrom} steps both by step-flow and through layer-by-layer growth. The distribution of islands on the terraces demonstrate that surface diffusion is an important factor during growth. Terraces that are less than the diffusion length do not contain any islands. This, together with the length scale of the inter island spacing and the denuded zones provide an estimate of the diffusion length. In situ experiments at very low supersaturation ({approximately}0.l%) show that growth is a discontinuous process due to step pinning. In addition, in situ images allow for the direct determination of the fundamental growth parameters {alpha}, the step edge energy, and {beta}, the kinetic coefficient.
Date: January 10, 1995
Creator: Land, T. A.; De Yoreo, J. J.; Lee, J. D. & Ferguson, J. R.
System: The UNT Digital Library
Optical scatter as a diagnostic tool for studying bulk defects which cause laser damage in conventional and rapid growth KP and DKDP (open access)

Optical scatter as a diagnostic tool for studying bulk defects which cause laser damage in conventional and rapid growth KP and DKDP

Single crystals of KH{sub 2}PO{sub 4} (KDP) and (D{sub x}H{sub 1-x}){sub 2}PO{sub 4} (DKDP) will be used for frequency conversion and as part of a large aperture optical switch in the proposed National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL). These crystals must have good optical properties and high laser damage thresholds. Currently these crystals have a lower laser damage threshold than other optical materials in the laser chain which has forced designers to limit the output fluence of the NIF in order to avoid damaging the crystals. Furthermore, while more efficient frequency conversion schemes are being explored both theoretically and experimentally, the advantages of these schemes can not be fully realized unless the damage thresholds of the conversion crystals are increased. Over the past decade, LLNL has generated an extensive data base on the laser damage in KDP and DKDP crystals both at the first and third harmonics of Nd-YAG. While the damage thresholds of these crystals have increased over this time period due, in part, to better filtration of the growth solution, the damage thresholds of the best crystals are still far below what is expected from theoretical limits calculated from the band structure of …
Date: July 10, 1995
Creator: Woods, B.; Runkel, M. & Yan, M.
System: The UNT Digital Library
Possible new class of dense white dwarfs (open access)

Possible new class of dense white dwarfs

If the strange quark matter hypothesis is true, then a new class of white dwarfs can exist whose nuclear material in their deep interiors can have a density as high as the neutron drip density, a few hundred times the density in maximum-mass white dwarfs and 4 {times} 10{sup 4} the density in dwarfs of typical mass, M {approximately} 0.6M{sub {circle_dot}}. Their masses fall in the approximate range 10{sup {minus}4} to 1M{sub {circle_dot}}. They are stable against acoustical modes of vibration. A strange quark core stabilizes these stars, which otherwise would have central densities that would place them in the unstable region of the sequence between white dwarfs and neutron stars.
Date: January 10, 1995
Creator: Glendenning, N.K.; Kettner, C. & Weber, F.
System: The UNT Digital Library
Livermore Imaging Fourier Transform Infrared Spectrometer (LIFTIRS) (open access)

Livermore Imaging Fourier Transform Infrared Spectrometer (LIFTIRS)

Lawrence Livermore National Laboratory is currently operating a hyperspectral imager, the Livermore Imaging Fourier Transform Infrared Spectrometer (LIFTIRS). This instrument is capable of operating throughout the infrared spectrum from 3 to 12.5 {mu}m with controllable spectral resolution. In this presentation we report on it`s operating characteristics, current capabilities, data throughput and calibration issues.
Date: May 10, 1995
Creator: Carter, M. R.; Bennett, C. L.; Fields, D. J. & Lee, F. D.
System: The UNT Digital Library
Underwater laser imaging system (UWLIS) (open access)

Underwater laser imaging system (UWLIS)

Practical limitations of underwater imaging systems are reached when the noise in the back scattered radiation generated in the water between the imaging system and the target obscures the spatial contrast and the resolution necessary for target discovery and identification. The advent of high power lasers operating in the oceanic transmission window of the visible spectrum (blue-green portion) has led to improved experimental illumination systems for underwater imaging The properties of laser bearm in range-gated and synchronously scanned devices take advantage of the unique temporal and spatial coherence effect of common volume back scatter to reduce or eliminate noise, increase signal to noise levels. Synchronously scanned systems rely on the highly collimated nature of the laser beam for spatial rejection of common volume back scatter. A synchronous, raster-scanning underwater laser imaging system (UWLIS) has been developed at Lawrence liver-more National Laboratory. The present UWLIS system differs from earlier synchronous scanners in its ability to scan in two dimensions at conventional video frame rate (30 Hz). The imaging performance of the present UWLIS was measured at distances of up to 6.3 AL (at a physical distance of 15.2 meters) during an in-water tank test and 4.5 to 5.0 AL (at a …
Date: March 10, 1995
Creator: DeLong, M. L. & Kulp, T. J.
System: The UNT Digital Library
Visualization methods for high-resolution, transient, 3-D, finite element situations (open access)

Visualization methods for high-resolution, transient, 3-D, finite element situations

Scientific visualization is the process whereby numerical data is transformed into a visual form to augment the process of discovery and understanding. Visualizing the data generated by large-scale, transient, three-dimensional finite element simulations poses many challenges due to geometric complexity, the presence of multiple materials and multiple element types, and the inherent unstructured nature of the meshes. In this paper, the direct use of finite element data structures, nodal assembly procedures, and element interpolants for volumetric adaptive surface extraction, surface rendering, vector grids and particle tracing is discussed. A brief description of a {open_quotes}direct-to-disk{close_quotes} animation system is presented, and case studies which demonstrate the use of isosurfaces, vector plots, cutting planes, reference surfaces and particle tracing are then discussed in the context of several case studies for transient incompressible viscous flow, and acoustic fluid-structure interaction simulations. An overview of the implications of massively parallel computers on visualization is presented to highlight the issues in parallel visualization methodology, algorithms. data locality and the ultimate requirements for temporary and archival data storage and network bandwidth.
Date: January 10, 1995
Creator: Christon, M. A.
System: The UNT Digital Library
Quartz substrates for EUVL reticles (open access)

Quartz substrates for EUVL reticles

A EUVL reticle blank was fabricated on a specially polished quartz blank. The stress-induced distortion of the multilayer coating was unacceptably large. The distortion can be effectively eliminated by coating the backside of the reticle blank with an identical coating. This strategy has the potential to eliminate multilayer induced stress distortion for the reticle blank in a manner which is compatible with the existing reticle fabrication infrastructure.
Date: February 10, 1995
Creator: Kania, D. R.; Weber, F. J.; Vernon, S. P.; Hawryluk, A.; Baker, S. L.; Golub, A. M. et al.
System: The UNT Digital Library
Issues in recycling galvanized scrap (open access)

Issues in recycling galvanized scrap

The quality of the steel used for most galvanizing (and tinplate) applications makes scrap derived from their production and use a premier solid charge material for steelmaking. In 1989 the AISI created a Task Force to define the issues and to recommend technologically and economically sound approaches to assure continued, unhindered recyclability of the growing volume of galvanized scrap. The AISI program addressed the treatment of full-sized industrial bales of scrap. The current, on-going MRI (US)--Argonne National Laboratory program is focused on ``loose`` scrap from industrial and post-consumer sources. Results from these programs, issues of scrap management from source to steel melting, the choices for handling zinc in iron and steelmaking and the benefits/costs for removal of zinc (and lead) from scrap prior to melting in BOF and foundry operations are reviewed in this paper.
Date: February 10, 1995
Creator: Koros, P.J.; Hellickson, D.A. & Dudek, F.J.
System: The UNT Digital Library
Resistance Weld Qualification Analysis for Radioactive Waste Canisters (open access)

Resistance Weld Qualification Analysis for Radioactive Waste Canisters

High level radioactive waste canisters are sealed by resistance upset welding to ensure leak tight closures. Resistance welding is fast, uniform, and can be performed remotely to minimize radiation exposure to the operators. Canisters are constructed in accordance with ASME Band PV Code, Section VIII, Division 1, however, the resistance welds are not used in Section VIII. The resistance welds are qualified by analysis using material properties obtained from the test coupons. Burst tests are performed on canister welds to meet ASME Section IX welder qualification requirements. Since burst tests are not used in Section IX for resistance weld qualification, finite element results of canister resistance welds are compared with the finite element analysis results of resistance weld tests in ASME Section IX, QW-196 to establish similarity between the two weld tests. Detailed analyses show that the primary mode of failure in both the tests is shear and, therefore, the use of burst test in place of shear test is acceptable. It is believed that the detailed analyses and results could help in establishing acceptance criteria for resistance upset welding in ASME B&PV Code, Sections VIII, and IX.
Date: January 10, 1995
Creator: Gupta, N.K. & Gong, C.
System: The UNT Digital Library
Phase control and measurement of ultrashort optical pulses (open access)

Phase control and measurement of ultrashort optical pulses

We have used the Direct Optical Spectral Phase Measurement (DOSPM) technique to characterize the cubic phase tuning ability of our pulse stretcher. We have compared the measured phase to the phase determined from cross-correlation measurements.
Date: February 10, 1995
Creator: Sullivan, A.; White, W.E.; Chu, K.C. & Heritage, J.P.
System: The UNT Digital Library
Class of service in the high performance storage system (open access)

Class of service in the high performance storage system

Quality of service capabilities are commonly deployed in archival mass storage systems as one or more client-specified parameters to influence physical location of data in multi-level device hierarchies for performance or cost reasons. The capabilities of new high-performance storage architectures and the needs of data-intensive applications require better quality of service models for modern storage systems. HPSS, a new distributed, high-performance, scalable, storage system, uses a Class of Service (COS) structure to influence system behavior. The authors summarize the design objectives and functionality of HPSS and describes how COS defines a set of performance, media, and residency attributes assigned to storage objects managed by HPSS servers. COS definitions are used to provide appropriate behavior and service levels as requested (or demanded) by storage system clients. They compare the HPSS COS approach with other quality of service concepts and discuss alignment possibilities.
Date: January 10, 1995
Creator: Louis, S. & Teaff, D.
System: The UNT Digital Library
Conversion of the rocket propellant UDMH to a reagent useful in vicarious nucleophilic substitution reactions (open access)

Conversion of the rocket propellant UDMH to a reagent useful in vicarious nucleophilic substitution reactions

The objective of our program is to develop novel, innovative solutions for the disposal of surplus energetic materials resulting from the demilitarization of conventional and nuclear munitions. In this report we describe the use of surplus propellant (UDMH) and explosives (TNT, Explosive D) as chemical precursors for higher value products. The conversion of UDMH to 1,1,1-trimethylhydrazinium iodide (TMHI) provides a new aminating reagent for use in Vicarious Nucleophilic Substitution (VNS) reactions. When TMHI is reacted with various nitroarenes the amino functionality is introduced in good to excellent yields. Thus, 2,4,6-trinitroaniline (picramide) reacts with TMHI to give 1,3,5-triamino-2,4,6-trinitroaniline (TATB) while 2,4,6-trinitrotoluene (TNT) reacts with TMHI to give 3,5-diamino-2,4,6-trinitrotoluene (DATNT). The advantages, scope and limitations of the VNS approach and the use of TMHI are discussed.
Date: November 10, 1995
Creator: Mitchell, A. R.; Pagoria, P. F. & Schmidt, R. D.
System: The UNT Digital Library
Nuclear waste, public information and residential property values (open access)

Nuclear waste, public information and residential property values

This document presents details about how increased public knowledge of high-level radioactive waste storage facilities effects the price of near-by residential properties.
Date: October 10, 1995
Creator: Clark, E.E. & Allison, T.
System: The UNT Digital Library
Phase transitions in ammonium perchlorate to 26 GPA and 700 K in a diamond anvil cell (open access)

Phase transitions in ammonium perchlorate to 26 GPA and 700 K in a diamond anvil cell

Ammonium perchlorate (AP) showed previously unreported phase behavior when studied in a diamond anvil cell (DAC) at high temperature (to 693 K) and high pressure (to {approximately}26 GPa). Liquid droplets, observed above the known 513 K orthorhombic-to-cubic phase transition, are interpreted as the onset to melting. The melting point decreased with increasing pressure. Mid-infrared FTIR spectra of the residue showed only AP. The AP melt may contribute to shock insensitivity of AP-based propellants. Gas formation was seen at higher temperatures. A phase diagram was constructed using the appearance of liquid and gas as solid-liquid and liquid-gas transitions. Preliminary pressurized differential scanning calorimetry data showed a weak pressure dependence (to {approximately}6.9 MPa) for the orthorhombic-to-cubic phase transition.
Date: July 10, 1995
Creator: Foltz, M.F. & Maienschein, J.L.
System: The UNT Digital Library
Relevance of the U.S. National Ignition Facility for driver and target options to next-step inertial fusion test facilities (open access)

Relevance of the U.S. National Ignition Facility for driver and target options to next-step inertial fusion test facilities

Achievement of inertial fusion ignition and energy gain in the proposed U.S. National Ignition Facility is a prerequisite for decisions to build next-step U.S. inertial fusion facilities for either high yield or high pulse-rate. There are a variety of target and driver options for such next-step inertial fusion test facilities, and this paper discusses possible ways that the NIF, using a 1.8 MJ glass laser in both direct and indirect-drive configurations, can provide target physics data relevant to several next-step facility options. Next step facility options include the Engineering Test Facility (ETF), which needs several-Hz pulse-rates for testing relevant to Inertial Fusion Energy (IFE) development. An option for high yield, called the Laboratory Microfusion Facility (LMF), does not require such high pulse-rates, but may still benefit from driver technologies capable of much higher shot rates than possible with glass lasers. A high-pulse-rate driver could also be used for a combined ETF/LMF facility, driving multiple target chambers with a common driver. Driver technologies that could support high-pulse rates for next-step options include heavy-ion and light-ion accelerators, diode-pumped solid-state lasers (DPSSL), and krypton-flouride gas lasers. The NIF could be used to provide important data for IFE in generic areas of target chamber …
Date: April 10, 1995
Creator: Logan, B. G.
System: The UNT Digital Library
Acoustic waves in random ensembles of magnetic fluxes (open access)

Acoustic waves in random ensembles of magnetic fluxes

To analyze the observational data and provide the appropriate diagnostic procedure for photospheric manifestation of solar oscillations it is necessary to take into account strong inhomogeneity of solar atmosphere with respect to distribution of magnetic fields. We study the collective phenomena in the propagation of acoustic waves and unsteady wave-packets through quite regions, sunspots and plages, including time-dependent response of these regions to solar oscillations, the energy transfer mechanisms, frequency shift effects and reradiation of the acoustic waves in higher layers of atmosphere. We show that the dynamics of differently magnetized regions, their dispersion properties, and their response to the propagation of acoustic waves are completely different. We describe the effects caused by the specific distribution and randomness of magnetic flux tubes, which can be observed and which can provide the tools for diagnostic goals.
Date: October 10, 1995
Creator: Ryutova, M.P.
System: The UNT Digital Library
Application of optical interconnect technology at Lawrence Livermore National Laboratory (open access)

Application of optical interconnect technology at Lawrence Livermore National Laboratory

Optical interconnects will be required to meet the information bandwidth requirements of future communication and computing applications. At Lawrence Livermore National Laboratory, the authors are involved in applying optical interconnect technologies in two distinct application areas: Multi-Gigabit/sec Computer Backplanes and Gigabit/sec Wide Area Networking using Wavelength Division Multiplexing. In this paper, the authors discuss their efforts to integrate optical interconnect technologies into prototype computing and communication systems.
Date: August 10, 1995
Creator: Haigh, R. E.; Lowry, M. E.; McCammon, K.; Hills, R.; Mitchell, R. & Sweider, D.
System: The UNT Digital Library
Series hybrid vehicles and optimized hydrogen engine design (open access)

Series hybrid vehicles and optimized hydrogen engine design

Lawrence Livermore, Sandia Livermore and Los Alamos National Laboratories have a joint project to develop an optimized hydrogen fueled engine for series hybrid automobiles. The major divisions of responsibility are: system analysis, engine design and kinetics modeling by LLNL; performance and emission testing, and friction reduction by SNL; computational fluid mechanics and combustion modeling by LANL. This project is a component of the Department of Energy, Office of Utility Technology, National Hydrogen Program. We report here on the progress on system analysis and preliminary engine testing. We have done system studies of series hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. The impact of various on-board storage options on fuel economy are evaluated. Experiments with an available engine at the Sandia Combustion Research Facility demonstrated NO{sub x} emissions of 10 to 20 ppm at an equivalence ratio of 0.4, rising to about 500 ppm at 0.5 equivalence ratio using neat hydrogen. Hybrid vehicle simulation studies indicate that exhaust NO{sub x} concentrations must be less than 180 ppm to meet the …
Date: May 10, 1995
Creator: Smith, J. R.; Aceves, S. & Van Blarigan, P.
System: The UNT Digital Library
Vicarious amination of nitroarenes with trimethylhydrazinium iodine (open access)

Vicarious amination of nitroarenes with trimethylhydrazinium iodine

This paper investigated the use of 1,1,1-trimethylhydrazinium iodide as a vicarious nucleophilic substitution reagent for introducing amino groups into nitroaromatic substrates. The substrates included nitroarenes, polynitrobenzenes, picramide, TNB,TNT, and dinitropyrazole; other nitroazoles are being studied.
Date: November 10, 1995
Creator: Pagoria, P. F.; Schmidt, R. D. & Mitchell, A. R.
System: The UNT Digital Library