CALIBRATION OF A VERTICAL-SCAN LONG TRACE PROFILER AT MSFC. (open access)

CALIBRATION OF A VERTICAL-SCAN LONG TRACE PROFILER AT MSFC.

The long trace profiler (LTP) is the instrument of choice for the surface figure measurement of grazing incidence mirrors. The modification of conventional LTP, the vertical-scan LTP, capable of measuring the surface figure of replicated shell mirrors is now in operation at Marshall Space Flight Center. A few sources of systematic error for vertical-scan LTP are discussed. Status of systematic error reduction is reported.
Date: July 31, 2001
Creator: GUBAREV,M.; KESTER,T. & TAKACS,P.Z.
System: The UNT Digital Library
Controlled Velocity Testing of an 8-kW Wind Turbine (open access)

Controlled Velocity Testing of an 8-kW Wind Turbine

This paper describes a case study of the controlled-velocity test of an 8-kW wind turbine. The turbine was developed in response to the U.S. Department of Energy's small wind turbine program. As background, the prototype development is discussed. The turbine mechanical and electrical components are described. The turbine was tested on a flatbed truck and driven down an airfield runway at constant relative wind speed. Horizontal furling was used to control over-speed. Various parameters were changed to determine their effects on furling. The testing showed that the machine had insufficient rotor offset for adequate furling. Also, a rotor resonance problem was discovered and remedied. Problems associated with taking the measurements made it difficult to determine if the truck test was a suitable method for code validation. However, qualitative observations gleaned from the testing justified the effort.
Date: July 31, 2001
Creator: Larwood, S.; Sencenbaugh, J. & Acker, B.
System: The UNT Digital Library
Equivalence Ratio-EGR Control of HCCI Engine Operation and the Potential for Transition to Spark-Ignited Operation (open access)

Equivalence Ratio-EGR Control of HCCI Engine Operation and the Potential for Transition to Spark-Ignited Operation

This research investigates a control system for HCCI engines, where equivalence ratio, fraction of EGR and intake pressure are adjusted as needed to obtain satisfactory combustion. HCCI engine operation is analyzed with a detailed chemical kinetics code, HCT (Hydrodynamics, Chemistry and Transport), that has been extensively modified for application to engines. HCT is linked to an optimizer that determines the operating conditions that result in maximum brake thermal efficiency, while meeting the peak cylinder pressure restriction. The results show the values of the operating conditions that yield optimum efficiency as a function of torque and rpm. The engine has high NO{sub x} emissions for high power operation, so the possibility of switching to stoichiometric operation for high torque conditions is considered. Stoichiometric operation would allow the use of a three-way catalyst to reduce NO{sub x} emissions to acceptable levels. Finally, the paper discusses the possibility of transitioning from HCCI operation to SI operation to achieve high power output.
Date: July 31, 2001
Creator: Martinez-Frias, J; Aceves, S M; Flowers, D L; Smith, J R & Dibble, R
System: The UNT Digital Library
Update on Optical Design of Adaptive Optics System at Lick Observatory (open access)

Update on Optical Design of Adaptive Optics System at Lick Observatory

In 1999, we presented our plan to upgrade the adaptive optics (AO) system on the Lick Observatory Shane telescope (3m) from a prototype instrument pressed into field service to a facility instrument. This paper updates the progress of that plan and details several important improvements in the alignment and calibration of the AO bench. The paper also includes a discussion of the problems seen in the original design of the tip/tilt (t/t) sensor used in laser guide star mode, and how these problems were corrected with excellent results.
Date: July 31, 2001
Creator: Bauman, B. J.; Gavel, D. T.; Waltjen, K. E.; Freeze, G. J.; Hurd, R. L.; Gates, E. I. et al.
System: The UNT Digital Library
Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography (open access)

Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography

The Learning Objective is to present to the forensic community a potential qualitative/quantitative method for trace-fiber color comparisons using micellar electrokinetic chromatography (MEKC). Developing a means of analyzing extracted dye constituents from millimeter-size nylon fiber samples was the objective of this research initiative. Aside from ascertaining fiber type, color evaluation and source comparison of trace-fiber evidence plays a critical role in forensic-fiber examinations. Literally thousands of dyes exist to date, including both natural and synthetic compounds. Typically a three-color-dye combination is employed to affect a given color on fiber material. The result of this practice leads to a significant number of potential dye combinations capable of producing a similar color and shade. Since a typical forensic fiber sample is 2 mm or less in length, an ideal forensic dye analysis would qualitatively and quantitatively identify the extracted dye constituents from a sample size of 1 mm or smaller. The goal of this research was to develop an analytical method for comparing individual dye constituents from trace-fiber evidence with dyes extracted from a suspected source, while preserving as much of the original evidence as possible.
Date: July 30, 2001
Creator: Lewis, L. A.
System: The UNT Digital Library
Architecture of a software quench management system (open access)

Architecture of a software quench management system

Testing superconducting accelerator magnets is inherently coupled with the proper handling of quenches; i.e., protecting the magnet and characterizing the quench process. Therefore, software implementations must include elements of both data acquisition and real-time controls. The architecture of the quench management software developed at Fermilab's Magnet Test Facility is described. This system consists of quench detection, quench protection, and quench characterization components that execute concurrently in a distributed system. Collaboration between the elements of quench detection, quench characterization and current control are discussed, together with a schema of distributed saving of various quench-related data. Solutions to synchronization and reliability in such a distributed quench system are also presented.
Date: July 30, 2001
Creator: al., Jerzy M. Nogiec et
System: The UNT Digital Library
Asymptotics, streamlines, and reservoir modeling: a pathway to production tomography (open access)

Asymptotics, streamlines, and reservoir modeling: a pathway to production tomography

None
Date: July 30, 2001
Creator: Vasco, D. W. & Datta-Gupta, Akhil
System: The UNT Digital Library
CHARGED PARTICLE MULTIPLICITIES AT BRAHMS. (open access)

CHARGED PARTICLE MULTIPLICITIES AT BRAHMS.

This report presents the measurement of charged particle multiplicity densities dN/d{eta} in ultrarelativistic heavy ion collisions as function of {eta} and the centrality of the collisions. This distributions were extracted from data collected by the BRAHMS collaboration during the first RHK run with gold ions at {radical}s{sub NN} = 130A {center_dot} GeV. The analysis method is described and, results are compared to some model predictions.
Date: July 30, 2001
Creator: DEBBE, R., FOR THE BRAHMS COLLABORATION
System: The UNT Digital Library
Deletion of a coordinate regulator of type 2 cytokine expression in mice (open access)

Deletion of a coordinate regulator of type 2 cytokine expression in mice

Mechanisms underlying the differentiation of stable T helper subsets will be important in understanding how discrete types of immunity develop in response to different pathogens. An evolutionarily conserved {approx}400 base pair non-coding sequence in the IL-4/IL-13 intergenic region, designated CNS-1, was deleted in mice. The capacity to develop Th2 cells was compromised in vitro and in vivo in the absence of CNS-1. Despite the profound effect in T cells, mast cells from CNS-1-deleted mice maintained their capacity to produce IL-4. A T cell-specific element critical for optimal expression of type 2 cytokines may represent evolution of a regulatory sequence exploited by adaptive immunity.
Date: July 30, 2001
Creator: Mohrs, Markus; Blankespoor, Catherine M.; Wang, Zhi-En; Loots, Gaby G.; Hadeiba, Husein; Shinkai, Kanade et al.
System: The UNT Digital Library
Design and development of Nb{sub 3}Sn single-layer common coil dipole magnet for VLHC (open access)

Design and development of Nb{sub 3}Sn single-layer common coil dipole magnet for VLHC

Common coil dipole magnets based on Nb{sub 3}Sn conductor and the React and Wind technology are a promising option for the next generation of hadron colliders. The react and wind technology has potential cost benefits in terms of cable insulation, structural materials and magnet fabrication. A common coil design allows the use of pre-reacted Nb{sub 3}Sn superconductor with low critical current degradation after bending. Fermilab in collaboration with LBNL is involved in the development of a single-layer common-coil dipole magnet with maximum field of 11 T and 40-50 mm aperture, for a future VLHC. The current magnetic and mechanical designs of the dipole model, magnet parameters along with the status of the program, are reported in this paper.
Date: July 30, 2001
Creator: al., Giorgio Ambrosio et
System: The UNT Digital Library
Induction accelerators for the phase rotator system (open access)

Induction accelerators for the phase rotator system

The principle of magnetic induction has been applied to the acceleration of high current beams in betatrons and a variety of induction accelerators. The linear induction accelerator (LIA) consists of a simple nonresonant structure where the drive voltage is applied to an axially symmetric gap that encloses a toroidal ferromagnetic material. The change in flux in the magnetic core induces an axial electric field that provides particle acceleration. This simple nonresonant (low Q) structure acts as a single turn transformer that can accelerate from hundreds of amperes to tens of kiloamperes, basically only limited by the drive impedance. The LIA is typically a low gradient structure that can provide acceleration fields of varying shapes and time durations from tens of nanoseconds to several microseconds. The efficiency of the LIA depends on the beam current and can exceed 50% if the beam current exceeds the magnetization current required by the ferromagnetic material. The acceleration voltage available is simply given by the expression V=A dB/dt. Hence, for a given cross section of material, the beam pulse duration influences the energy gain. Furthermore, a premium is put on minimizing the diameter, which impacts the total weight or cost of the magnetic material. The …
Date: July 30, 2001
Creator: Reginato, Lou; Yu, Simon & Vanecek, Dave
System: The UNT Digital Library
Model-Based Detection in a Shallow Water Ocean Environment (open access)

Model-Based Detection in a Shallow Water Ocean Environment

A model-based detector is developed to process shallow water ocean acoustic data. The function of the detector is to adaptively monitor the environment and decide whether or not a change from normal has occurred. Here we develop a processor incorporating both a normal-mode ocean acoustic model and a vertical hydrophone array. The detector is applied to data acquired from the Hudson Canyon experiments at various ranges and its performance is evaluated.
Date: July 30, 2001
Creator: Candy, J V
System: The UNT Digital Library
Nb{sub 3}Sn ARC quadrupole magnets for VLHC (open access)

Nb{sub 3}Sn ARC quadrupole magnets for VLHC

Superconducting quadrupoles with a field gradient of 400-450 T/m for a future Very Large Hadron Collider (VLHC) are being studied at Fermilab. To reach the target field gradient in a 40-50 mm aperture, Nb{sub 3}Sn superconductor is used at an operating temperature of 4.2 K. Two cases with different magnet functions, beam separation distances and coil arrangements have been analyzed and optimized in order to provide the required field quality and magnet parameters.
Date: July 30, 2001
Creator: Zlobin, Vadim V. Kashikhin and Alexander V.
System: The UNT Digital Library
Quench Protection of High Field Nb{sub 3}Sn Magnets for VLHC (open access)

Quench Protection of High Field Nb{sub 3}Sn Magnets for VLHC

Fermilab is developing high field magnets for a possible future VLHC. The high levels of stored energy in these magnets present significant challenges to the magnet quench protection. Simulation programs have been developed and used to analyze temperature and voltage distributions during a quench and to performed parametric studies on conductor and quench-heater requirements. This paper concludes with a proposal for a set of quench protection parameters for the VLHC magnets.
Date: July 30, 2001
Creator: al., Linda Imbasciati et
System: The UNT Digital Library
Reactions Involved in Fingerprint Development Using the Cyanoacrylate - Fuming Method (open access)

Reactions Involved in Fingerprint Development Using the Cyanoacrylate - Fuming Method

The Learning Objective is to present the basic chemistry research findings to the forensic community regarding development of latent fingerprints using the cyanoacrylate fuming method. Chemical processes involved in the development of latent fingerprints using the cyanoacrylate fuming method have been studied, and will be presented. Two major types of latent prints have been investigated--clean (eccrine) and oily (sebaceous) prints. Scanning electron microscopy (SEM) was used as a tool for determining the morphology of the polymer developed separately on clean and oily prints after cyanoacrylate fuming. A correlation between the chemical composition of an aged latent fingerprint, prior to development, and the quality of a developed fingerprint was observed in the morphology. The moisture in the print prior to fuming was found to be a critical factor for the development of a useful latent print. In addition, the amount of time required to develop a high quality latent print was found to be minimal. The cyanoacrylate polymerization process is extremely rapid. When heat is used to accelerate the fuming process, typically a period of 2 minutes is required to develop the print. The optimum development time is dependent upon the concentration of cyanoacrylate vapors within the enclosure.
Date: July 30, 2001
Creator: Lewis, L. A.
System: The UNT Digital Library
Shoe-String Automation (open access)

Shoe-String Automation

Faced with a downsizing organization, serious budget reductions and retirement of key metrology personnel, maintaining capabilities to provide necessary services to our customers was becoming increasingly difficult. It appeared that the only solution was to automate some of our more personnel-intensive processes; however, it was crucial that the most personnel-intensive candidate process be automated, at the lowest price possible and with the lowest risk of failure. This discussion relates factors in the selection of the Standard Leak Calibration System for automation, the methods of automation used to provide the lowest-cost solution and the benefits realized as a result of the automation.
Date: July 30, 2001
Creator: Duncan, M. L.
System: The UNT Digital Library
Single-layer high field dipole magnets (open access)

Single-layer high field dipole magnets

Fermilab is developing high field dipole magnets for post-LHC hadron colliders. Several designs with a nominal field of 10-12 T, coil bore size of 40-50 mm based on both shell-type and block-type coil geometry are currently under consideration. This paper presents a new approach to magnet design, based on simple and robust single-layer coils optimized for the maximum field, good field quality and minimum number of turns.
Date: July 30, 2001
Creator: Zlobin, Vadim V. Kashikhin and Alexander V.
System: The UNT Digital Library
Surface electrochemistry of CO on Pt(111): Anion Effects (open access)

Surface electrochemistry of CO on Pt(111): Anion Effects

In-situ studies of CO adsorption by surface x-ray scattering (SXS) and Fourier transform infrared (FTIR) spectroscopy techniques are used to create the link between the macroscopic kinetic rates of CO oxidation and the microscopic level of understanding the structure/site occupancy of CO on Pt(111). A remarkable difference in activity was observed between alkaline and acid solutions. In alkaline solution the oxidation of CO proceeds at low overpotential (<0.2 V) by the surface reaction between the adsorbed CO and OH, the latter forming selectively in the hydrogen underpotential potential region at defect sites. In acid solution these sites are blocked by specific adsorption of anions, and consequently in a solution containing Br{sup -} the ignition potential is shifted positively by 0.6 V. Anions of supporting electrolytes also have dramatic effects on both the potential range of stability and the domain size of the p(2x2)-3CO structure which is formed at 0.05 V. The stability/domain size of this structure increases from KOH (ca. 30 {angstrom} between 0.05 < E < 0.3V), to HClO{sub 4} (ca. 140 {angstrom} between 0.05 < E < 0.6V) to HClO{sub 4} + Br{sup -} (ca 350 {angstrom} between 0.05 < E < 0.8V). The larger the ordered domains …
Date: July 30, 2001
Creator: Markovic, N.M.; Lucas, C.A.; Rodes, A.; Stamenkovic, V. & Ross, P.N.
System: The UNT Digital Library
NOVEL INTEGRATING SOLID STATE DETECTOR WITH SEGMENTATION FOR SCANNING TRANSMISSION SOFT X-RAY MICROSCOPY. (open access)

NOVEL INTEGRATING SOLID STATE DETECTOR WITH SEGMENTATION FOR SCANNING TRANSMISSION SOFT X-RAY MICROSCOPY.

An integrating solid state detector with segmentation has been developed that addresses the needs in scanning transmission x-ray microscopy below 1 keV photon energy. The detector is not cooled and can be operated without an entrance window which leads to a total photon detection efficiency close to 100%. The chosen segmentation with 8 independent segments is matched to the geometry of the STXM to maximize image mode flexibility. In the bright field configuration for 1 ms integration time and 520 eV x-rays the rms noise is 8 photons per integration.
Date: July 29, 2001
Creator: FESER,M. JACOBSEN,C. REHAK,P. DE GERONIMO,G. HOLL,P. STUDER,L.
System: The UNT Digital Library
Novel Integrating Solid State Detector With Segmentation For Scanning Transmission Soft X-Ray Microscopy. (open access)

Novel Integrating Solid State Detector With Segmentation For Scanning Transmission Soft X-Ray Microscopy.

An integrating solid state detector with segmentation has been developed that addresses the needs in scanning transmission x-ray microscopy below 1 keV photon energy. The detector is not cooled and can be operated without an entrance window which leads to a total photon detection efficiency close to 100%. The chosen segmentation with 8 independent segments is matched to the geometry of the STXM to maximize image mode flexibility. In the bright field configuration for 1 ms integration time and 520 eV x-rays the rms noise is 8 photons per integration.
Date: July 29, 2001
Creator: Feser, M.; Jacobsen, C.; Rehak, P.; De Geronimo, G.; Holl, P. & Studer, L.
System: The UNT Digital Library
Breeding 10{sup 10}/s Radioactive Nuclei in a Compact Plasma Focus Device (open access)

Breeding 10{sup 10}/s Radioactive Nuclei in a Compact Plasma Focus Device

In the early 90's, it was discovered that a Plasma Focus (PF) system self-creates a plasma-tarp in which high energy-threshold nuclear-reactions occur at high reaction rates. Short life radioisotopes (SLR)s such as {sup 18}F, {sup 17}F, {sup 15}O, {sup 14}O, {sup 13}N have been generated (10{sup 6} - 10{sup 8} per pulse) with a PF-machine using 7 kJ energy storage to produce the plasmas. {beta}{sup -} radioactivity from the SLRs is measured with rugged, Geiger counters inserted into the PF-chamber, and a specific SLR is identified by its half-life. The PF chamber (before discharge) is filled with a mixture of gases that constitutes the latter plasma-target--beam system, e.g., the elements required to produce specific SLRs through nuclear reactions. In this paper, arguments are presented showing that a modest sized PF-machine, using a 50-75 kJ fast capacitor-bank, when operated at pulse frequencies of 1-10 Hz can produce {ge} 10{sup 9} SLRs/pulse. This paper reports the result s of testing a PF as a breeder of SLRs with dual applications for: (1) Secondary Radioactive Nuclear Beams ion-sources (Z < 35), and (2) as a breeder of radioisotopes for biomedicine (Z {le} 10) and/or PET imaging.
Date: July 27, 2001
Creator: Brzosko, JANS.
System: The UNT Digital Library
A case study in application I/O on Linux clusters. (open access)

A case study in application I/O on Linux clusters.

A critical but often ignored component of system performance is the I/O system. Today's applications expect a great deal from underlying storage systems and software, and both high performance distributed storage and high level interfaces have been developed to fill these needs. In this paper they discuss the I/O performance of a parallel scientific application on a Linux cluster, the FLASH astrophysics code. This application relies on three I/O software components to provide high performance parallel I/O on Linux clusters: the Parallel Virtual File System (PVFS), the ROMIO MPI-IO implementation, and the Hierarchical Data Format (HDF5) library. First they discuss the roles played by each of these components in providing an I/O solution. Next they discuss the FLASH I/O benchmark and point out its relevance. Following this they examine the performance of the benchmark, and through instrumentation of both the application and underlying system software code they discover the location of major software bottlenecks. They work around the most inhibiting of these bottlenecks, showing substantial performance improvement. Finally they point out similarities between the inefficiencies found here and those found in message passing systems, indicating that research in the message passing field could be leveraged to solve similar problems in …
Date: July 27, 2001
Creator: Ross, R.; Nurmi, D.; Cheng, A. & Zingale, M.
System: The UNT Digital Library
LLNL Identification Program: Regional Body-Wave Correction Surfaces and Surface-Wave Tomography Models to Improve Discrimination (open access)

LLNL Identification Program: Regional Body-Wave Correction Surfaces and Surface-Wave Tomography Models to Improve Discrimination

LLNL identification research is focused on the problem of correctly discriminating small-magnitude explosions from a background of earthquakes, mining tremors, and other events. The goal is to reduce the variance within the population of each type of event, while increasing the separation between the explosions and the other event types. We address this problem for both broad categories of seismic waves: body waves and surface waves. First, we map out the effects of propagation and source size in advance so that they can be accounted for and removed from observed events. This can dramatically reduce the population variance. Second, we try to optimize the measurement process to improve the separation between population types. For body waves we focus on the identification power of the short-period regional phases Pn, Pg, Sn and Lg, which can often be detected down to very small magnitudes. Many studies have shown that particular ratios of these phases, such as 6-to 8-Hz Pn/Lg, can effectively discriminate between closely located explosions and earthquakes. To extend this discrimination power over broad areas, we use our revised Magnitude and Distance Amplitude Correction (MDAC2) procedure. This joint source and path model fits the observed spectra and removes magnitude and distance …
Date: July 27, 2001
Creator: Walter, W.; Rodgers, A. J.; Pasyanos, M. E.; Mayeda, K. M.; Sicherman, A. & Harris, D. B.
System: The UNT Digital Library
LLNL Seismic Locations: Validating Improvement Through Integration of Regionalized Models and Empirical Corrections (open access)

LLNL Seismic Locations: Validating Improvement Through Integration of Regionalized Models and Empirical Corrections

The monitoring of nuclear explosions on a global basis requires accurate event locations. As an example, a typical size used for an on-site inspection search area is 1,000 square kilometers or approximately 17 km accuracy, assuming a circular area. This level of accuracy is a significant challenge for small events that are recorded using a sparse regional network. In such cases, the travel time of seismic energy is strongly affected by crustal and upper mantle heterogeneity and large biases can result. This can lead to large systematic errors in location and, more importantly, to invalid error bounds associated with location estimates. Calibration data and methods are being developed and integrated to correct for these biases. Our research over the last few years has shown that one of the most effective approaches to generate path corrections is the hybrid technique that combine both regionalized models with three-dimensional empirical travel-time corrections. We implement a rigorous and comprehensive uncertainty framework for these hybrid approaches. Qualitative and quantitative validations are presented in the form of single component consistency checks, sensitivity analysis, robustness measures, outlier testing along with end-to-end testing of confidence measures. We focus on screening and validating both empirical and model based calibrations …
Date: July 27, 2001
Creator: Schultz, C. A.; Flanagan, M. P.; Myers, S. C.; Pasyanos, M. E.; Swenson, J. L.; Hanley, W. et al.
System: The UNT Digital Library