Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors. (open access)

Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors.

Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurement using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 …
Date: March 1, 2005
Creator: Haskins, William E.; Leavell, Michael D.; Lane, Pamela; Jacobsen, Richard B.; Hong, Joohee; Ayson, Marites J. et al.
Object Type: Report
System: The UNT Digital Library
Differentiating neutrino models on the basis of $\theta_{13}$ and lepton flavor violation (open access)

Differentiating neutrino models on the basis of $\theta_{13}$ and lepton flavor violation

The authors show how models of neutrino masses and mixings can be differentiated on the basis of their predictions for {theta}{sub 13} and lepton flavor violation in radiative charged lepton decays and {mu} - e conversion. They illustrate the lepton flavor violation results for five predictive SO(10) SUSY GUT models and point out the relative importance of their heavy right-handed neutrino mass spectra and {theta}{sub 13} predictions.
Date: March 1, 2008
Creator: Albright, Carl H.
Object Type: Article
System: The UNT Digital Library
The U.S. Department of Energy's Aerial Measuring System (AMS) (open access)

The U.S. Department of Energy's Aerial Measuring System (AMS)

For nearly 40 years, aerial radiological search and survey missions have been performed by the United States Department of Energy's (USDOE) Remote Sensing Laboratory (RSL). Originally created in 1967 as Aerial Measurement Operations (AMO), the AMS mission has expanded to include acquiring baseline measurements, performing periodic area monitoring, and responding to radiological emergencies. In an accident scenario, AMS fixed-wing and/or rotary-wing systems can be deployed to map radiological deposition. A fixed-wing system is on standby twenty-fours per day, seven days per week and can be deployed within four hours of notification. It can quickly evaluate high levels of radiation which may constitute immediate health risks. To accomplish its mission the fixed-wing aircraft utilizes the Spectral Aerial Radiological Computer System (SPARCS) which records gross count and spectral information. Data from SPARCS is telemetered to ground stations and secure websites where it can be viewed and evaluated in near-real time. The rotary-wing system deploys following the critical phase of an accident and supports the DOE's Consequence Management Response Team (CMRT) in determining long term consequences of the accident. The rotary wing aircraft utilizes the Radiation and Environmental Data Acquisition and Recording System (REDAR). A 25-liter sodium iodide (NaI) spectral system and precise …
Date: March 1, 2008
Creator: Marianno, Craig
Object Type: Article
System: The UNT Digital Library
Impact Tensile Testing of Stainless Steels at Various Temperatures (open access)

Impact Tensile Testing of Stainless Steels at Various Temperatures

Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern (1 to 300 per second) are not well documented. However, research is being performed at the Idaho National Laboratory to quantify these characteristics. The work presented herein discusses tensile impact testing of dual-marked 304/304L and 316/316L stainless steel material specimens. Both base material and welded material specimens were tested at -20 oF, room temperature, 300 oF, and 600 oF conditions. Utilizing a drop weight impact test machine and 1/4-inch and 1/2-inch thick dog bone-shaped test specimens, a strain rate range of approximately 4 to 40 per second (depending on initial temperature conditions) was achieved. Factors were determined that reflect the amount of increased strain energy the material can absorb due to strain rate effects. Using the factors, elevated true stress-strain curves for these materials at various strain rates and temperatures were generated. By incorporating the strain rate elevated true stress-strain material curves into an inelastic finite element computer program as …
Date: March 1, 2008
Creator: Morton, D. K.
Object Type: Report
System: The UNT Digital Library
Determination of Basic Structure-Property Relations for Processing and Modeling in Advanced Nuclear Fuel: Microstructure Evolution and Mechanical Properties (open access)

Determination of Basic Structure-Property Relations for Processing and Modeling in Advanced Nuclear Fuel: Microstructure Evolution and Mechanical Properties

The project objective is to study structure-property relations in solid solutions of nitrides and oxides with surrogate elements to simulate the behavior of fuels of inert matrix fuels of interest to the Advanced Fuel Cycle Initiative (AFCI), with emphasis in zirconium-based materials. Work with actual fuels will be carried out in parallel in collaboration with Los Alamos National Laboratory (LANL). Three key aspects will be explored: microstructure characterization through measurement of global texture evolution and local crystallographic variations using Electron Backscattering Diffraction (EBSD); determination of mechanical properties, including fracture toughness, quasi-static compression strength, and hardness, as functions of load and temperature, and, finally, development of structure-property relations to describe mechanical behavior of the fuels based on experimental data. Materials tested will be characterized to identify the mechanisms of deformation and fracture and their relationship to microstructure and its evolution. New aspects of this research are the inclusion of crystallographic information into the evaluation of fuel performance and the incorporation of statistical variations of microstructural variables into simplified models of mechanical behavior of fuels that account explicitly for these variations. The work is expected to provide insight into processing conditions leading to better fuel performance and structural reliability during manufacturing and …
Date: March 1, 2009
Creator: Wheeler, Kirk; Parra, Manuel & Peralta, Pedro
Object Type: Report
System: The UNT Digital Library
Cosmological Analysis From Large-Scale Anisotropic Correlation Function of the Sloan Digital Sky Survey (open access)

Cosmological Analysis From Large-Scale Anisotropic Correlation Function of the Sloan Digital Sky Survey

None
Date: March 1, 2008
Creator: Okumura, Teppei & U., /Nagoya
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Update on Mechanical Analysis of Monolithic Fuel Plates (open access)

Update on Mechanical Analysis of Monolithic Fuel Plates

Results on the relative bond strength of the fuel-clad interface in monolithic fuel plates have been presented at previous RRFM conferences. An understanding of mechanical properties of the fuel, cladding, and fuel / cladding interface has been identified as an important area of investigation and quantification for qualification of monolithic fuel forms. Significant progress has been made in the area of mechanical analysis of the monolithic fuel plates, including mechanical property determination of fuel foils, cladding processed by both hot isostatic pressing and friction bonding, and the fuel-clad composite. In addition, mechanical analysis of fabrication induced residual stress has been initiated, along with a study to address how such stress can be relieved prior to irradiation. Results of destructive examinations and mechanical tests are presented along with analysis and supporting conclusions. A brief discussion of alternative non-destructive evaluation techniques to quantify not only bond quality, but also bond integrity and strength, will also be provided. These are all necessary steps to link out-of-pile observations as a function of fabrication with in-pile behaviours.
Date: March 1, 2008
Creator: Burkes, D. E.; Rice, F. J.; Jue, J.-F. & Hallinan, N. P.
Object Type: Article
System: The UNT Digital Library
Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on San Juan Basin Coal (open access)

Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on San Juan Basin Coal

The major objectives of this project were to (a) measure the adsorption behavior of pure methane, nitrogen, CO{sub 2} and their binary and ternary mixtures on wet Tiffany coal at 130 F and pressures to 2000 psia; (b) correlate the equilibrium adsorption isotherm data using the extended Langmuir model, the Langmuir model, the loading ratio correlation and the Zhou-Gasem-Robinson equation of state; and (c) establish sorption-time estimates for the pure components. Specific accomplishments are summarized below regarding the complementary tasks involving experimental work and data correlation. Representative coal samples from BP Amoco Tiffany Injection Wells No.1 and No.10 were prepared, as requested. The equilibrium moisture content and particle size distribution of each coal sample were determined. Compositional coal analyses for both samples were performed by Huffman Laboratories, Inc. Pure gas adsorption for methane on wet Tiffany coal samples from Injection Wells No.1 and No.10 was measured separately at 130 F (327.6 K) and pressures to 2000 psia (13.7 MPa). The average expected uncertainty in these data is about 3% (9 SCF/ton). Our measurements indicate that the adsorption isotherms of the two coal samples exhibit similar Langmuir-type behavior. For the samples from the two wells, a maximum variation of about 5% …
Date: March 1, 2002
Creator: Gasem, K. A. M.; Robinson, R. L. & Reeves, S. R.
Object Type: Report
System: The UNT Digital Library
Measurement of the ttbar production cross section in the MET+jets channel at CDF (open access)

Measurement of the ttbar production cross section in the MET+jets channel at CDF

This thesis is focused on an inclusive search of the t{bar t} {yields} E{sub T} + jets decay channel by means of neural network tools in proton antiproton collisions at {radical}s = 1.96 TeV recorded by the Collider Detector at Fermilab (CDF). At the Tevatron p{bar p} collider top quarks are mainly produced in pairs through quark-antiquark annihilation and gluon-gluon fusion processes; in the Standard Model description, the top quark then decays to a W boson and a b quark almost 100% of the times, so that its decay signatures are classified according to the W decay modes. When only one W decays leptonically, the t{bar t} event typically contains a charged lepton, missing transverse energy due to the presence of a neutrino escaping from the detector, and four high transverse momentum jets, two of which originate from b quarks. In this thesis we describe a t{bar t} production cross section measurement which uses data collected by a 'multijet' trigger, and selects this kind of top decays by requiring a high-P{sub T} neutrino signature and by using an optimized neural network to discriminate top quark pair production from backgrounds. In Chapter 1, a brief review of the Standard Model of …
Date: March 1, 2008
Creator: Compostella, Gabriele & /INFN, Trento
Object Type: Thesis or Dissertation
System: The UNT Digital Library
FRMAC Mission Analysis: What is it, and why is it useful? (open access)

FRMAC Mission Analysis: What is it, and why is it useful?

In 2002, the Director of the U.S. Department of Energy's (DOE's) National Nuclear Security Administration, Division of Emergency Response, requested a team of DOE scientists, considered experts in the field of radiological consequence management, assemble and construct a mission analysis upon which the DOE could build its response program and plan for future requirements. The team developed five scenarios upon which to build the data quality objectives (DQOs) that they considered necessary to ensure a comprehensive consequence management response from the DOE perspective. The resulting document was called the Consequence Management Mission Analysis. Based upon the positive reaction to this document and its obvious benefit to the Consequence Management mission, it was decided to expand the scope of the document to cover a mission analysis of the entire Federal Radiological Monitoring and Assessment Center (FRMAC) mission. The documentation team was expanded to include representatives from all signatories to the National Response Plan who have a role in responding to radiological emergencies. The scope of the FRMAC Mission Analysis includes all federal response resources which are activated to provide rapid support to affected state and local governments in the form of radiological monitoring and dose assessment activities at the incident site. …
Date: March 1, 2008
Creator: Hopkins, Rhonda
Object Type: Article
System: The UNT Digital Library
Hydrogen Analysis Group (open access)

Hydrogen Analysis Group

NREL factsheet that describes the general activites of the Hydrogen Analysis Group within NREL's Hydrogen Technologies and Systems Center.
Date: March 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Comparative Genome Analysis in the Integrated Microbial Genomes (IMG) System (open access)

Comparative Genome Analysis in the Integrated Microbial Genomes (IMG) System

Comparative genome analysis is critical for the effectiveexploration of a rapidly growing number of complete and draft sequencesfor microbial genomes. The Integrated Microbial Genomes (IMG) system(img.jgi.doe.gov) has been developed as a community resource thatprovides support for comparative analysis of microbial genomes in anintegrated context. IMG allows users to navigate the multidimensionalmicrobial genome data space and focus their analysis on a subset ofgenes, genomes, and functions of interest. IMG provides graphicalviewers, summaries and occurrence profile tools for comparing genes,pathways and functions (terms) across specific genomes. Genes can befurther examined using gene neighborhoods and compared with sequencealignment tools.
Date: March 1, 2006
Creator: Kyrpides, Nikos C. & Markowitz, Victor M.
Object Type: Article
System: The UNT Digital Library
Hydrogen Scenario Analysis Summary Report: Analysis of the Transition to Hydrogen Fuel Cell Vehicles and the Potential Hydrogen Energy Infrastructure Requirements (open access)

Hydrogen Scenario Analysis Summary Report: Analysis of the Transition to Hydrogen Fuel Cell Vehicles and the Potential Hydrogen Energy Infrastructure Requirements

Achieving a successful transition to hydrogen-powered vehicles in the U.S. automotive market will require strong and sustained commitment by hydrogen producers, vehicle manufacturers, transporters and retailers, consumers, and governments. The interaction of these agents in the marketplace will determine the real costs and benefits of early market transformation policies, and ultimately the success of the transition itself. The transition to hydrogen-powered transportation faces imposing economic barriers. The challenges include developing and refining a new and different power-train technology, building a supporting fuel infrastructure, creating a market for new and unfamiliar vehicles, and achieving economies of scale in vehicle production while providing an attractive selection of vehicle makes and models for car-buyers. The upfront costs will be high and could persist for a decade or more, delaying profitability until an adequate number of vehicles can be produced and moved into consumer markets. However, the potential rewards to the economy, environment, and national security are immense. Such a profound market transformation will require careful planning and strong, consistent policy incentives. Section 811 of the Energy Policy Act (EPACT) of 2005, Public Law 109-59 (U.S. House, 2005), calls for a report from the Secretary of Energy on measures to support the transition to …
Date: March 1, 2008
Creator: Greene, David L.; Leiby, Paul Newsome; James, Brian; Perez, Julie; Melendez, Margo; Milbrandt, Anelia et al.
Object Type: Report
System: The UNT Digital Library
Measurement of the ratio of the p anti-p ---> W+c-jet cross section to the inclusive p anti-p ---> W+jets cross section (open access)

Measurement of the ratio of the p anti-p ---> W+c-jet cross section to the inclusive p anti-p ---> W+jets cross section

None
Date: March 1, 2008
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Si Memory Chip as a Sensitive Neutron Detector (open access)

Si Memory Chip as a Sensitive Neutron Detector

A novel neutron detector is based on semiconductor technology. A boron-containing film is an integral part of the semiconductor device and is in physical contact with the charge-storage medium (CSM). The CSM is a proprietary cell design known as MirrorBit{trademark}, which is different from conventional memory designs such as SRAM or DRAM. The design doubles the resolution and sensitivity in the array. This enables a highly effective detection of the secondary particles, {sup 7}Li and {sup 4}He, produced due to neutron capture by {sup 10}B in the device. Other approaches using semiconductor materials for neutron detection have employed single-diode detectors that require off-system preamplifiers to filter and condition the signal. There are several advantages to this non-volatile detector, one being that it requires no power for detection and retains the signal until reset. Further, this detector, a semiconductor chip, can be seamlessly integrated into other systems. Finally, the semiconductor manufacturing process on which the detector is based will allow for a high-volume and low-cost alternative to current detectors. MirrorBit{trademark} chips were exposed to neutron flux and the signals recorded. Detailed results from this experiment will be described in this presentation.
Date: March 1, 2008
Creator: Quam, William
Object Type: Article
System: The UNT Digital Library
Creating and Implementing a Regularized Monitoring and EnforcementSystem for China's Mandatory Standards and Energy Information Label forAppliances (open access)

Creating and Implementing a Regularized Monitoring and EnforcementSystem for China's Mandatory Standards and Energy Information Label forAppliances

China has developed a comprehensive program of energy efficiency standards and labels for household appliances. In 1989, China first launched its minimum energy performance standards (MEPS), which are now applied to an extensive list of products. In 1998, China launched a voluntary energy endorsement label, which has grown to cover both energy-saving and water-saving products. And, in 2005, China launched a mandatory energy information label that initially covered two products. CLASP has assisted China in developing 11 minimum energy performance standards (MEPS) for 9 products and endorsement labels for 11 products including: refrigerators; air conditioners; televisions; printers; computers; monitors; fax machines; copiers; DVD/VCD players; external power supplies; and set-top boxes. CLASP has also assisted China in the development of the mandatory energy information label. Increasingly, attention is being placed on maximum energy savings from China's standards and labeling (S&L) efforts in order to meet the recently announced goal of reducing China's energy intensity by 20 percent by 2010 with an interim objective of 4 percent in 2006. China's mandatory standards system is heavily focused on the technical requirements for efficiency performance, but historically, it has lacked administrative and personnel capacity to undertake monitoring and enforcement of these legally binding standards. …
Date: March 1, 2007
Creator: Lin, Jiang
Object Type: Report
System: The UNT Digital Library
Yucca Mountain licensing support network archive assistant. (open access)

Yucca Mountain licensing support network archive assistant.

This report describes the Licensing Support Network (LSN) Assistant--a set of tools for categorizing e-mail messages and documents, and investigating and correcting existing archives of categorized e-mail messages and documents. The two main tools in the LSN Assistant are the LSN Archive Assistant (LSNAA) tool for recategorizing manually labeled e-mail messages and documents and the LSN Realtime Assistant (LSNRA) tool for categorizing new e-mail messages and documents. This report focuses on the LSNAA tool. There are two main components of the LSNAA tool. The first is the Sandia Categorization Framework, which is responsible for providing categorizations for documents in an archive and storing them in an appropriate Categorization Database. The second is the actual user interface, which primarily interacts with the Categorization Database, providing a way for finding and correcting categorizations errors in the database. A procedure for applying the LSNAA tool and an example use case of the LSNAA tool applied to a set of e-mail messages are provided. Performance results of the categorization model designed for this example use case are presented.
Date: March 1, 2008
Creator: Dunlavy, Daniel M.; Bauer, Travis L.; Verzi, Stephen J.; Basilico, Justin Derrick & Shaneyfelt, Wendy
Object Type: Report
System: The UNT Digital Library
Assessment of Cavitation-Erosion Resistance of Potential Pump Impeller Materials for Mercury Service at the Spallation Neutron Source (open access)

Assessment of Cavitation-Erosion Resistance of Potential Pump Impeller Materials for Mercury Service at the Spallation Neutron Source

Using a standard vibratory horn apparatus, the relative cavitation-erosion resistance of a number of cast alloys in mercury was evaluated to facilitate material selection decisions for Hg pumps. The performance of nine different alloys - in the as-cast condition as well as following a case-hardening treatment intended to increase surface hardness - was compared in terms of weight loss and surface profile development as a function of sonication time in Hg at ambient temperature. The results indicated that among several potentially suitable alloys, CD3MWCuN perhaps exhibited the best overall resistance to cavitation in both the as-cast and surface treated conditions while the cast irons examined were found unsuitable for service of this type. However, other factors, including cost, availability, and vendor schedules may influence a material selection among the suitable alloys for Hg pumps.
Date: March 1, 2007
Creator: Pawel, Steven J
Object Type: Report
System: The UNT Digital Library
Macro-meso-microsystems integration in LTCC : LDRD report. (open access)

Macro-meso-microsystems integration in LTCC : LDRD report.

Low Temperature Cofired Ceramic (LTCC) has proven to be an enabling medium for microsystem technologies, because of its desirable electrical, physical, and chemical properties coupled with its capability for rapid prototyping and scalable manufacturing of components. LTCC is viewed as an extension of hybrid microcircuits, and in that function it enables development, testing, and deployment of silicon microsystems. However, its versatility has allowed it to succeed as a microsystem medium in its own right, with applications in non-microelectronic meso-scale devices and in a range of sensor devices. Applications include silicon microfluidic ''chip-and-wire'' systems and fluid grid array (FGA)/microfluidic multichip modules using embedded channels in LTCC, and cofired electro-mechanical systems with moving parts. Both the microfluidic and mechanical system applications are enabled by sacrificial volume materials (SVM), which serve to create and maintain cavities and separation gaps during the lamination and cofiring process. SVMs consisting of thermally fugitive or partially inert materials are easily incorporated. Recognizing the premium on devices that are cofired rather than assembled, we report on functional-as-released and functional-as-fired moving parts. Additional applications for cofired transparent windows, some as small as an optical fiber, are also described. The applications described help pave the way for widespread application of …
Date: March 1, 2007
Creator: De Smet, Dennis J.; Nordquist, Christopher Daniel; Turner, Timothy Shawn; Rohrer, Brandon Robinson; Walker, Charles A.; Ho, Clifford K.. et al.
Object Type: Report
System: The UNT Digital Library
Longest-Serving Active Paper Mill in the Western United States Uncovers New Ways to Save Energy (open access)

Longest-Serving Active Paper Mill in the Western United States Uncovers New Ways to Save Energy

This case study describes how West Linn Paper Company's coated paper mill in West Linn, Oregon, saves nearly 58,200 MMBtu and $379,000 annually after receiving a DOE Save Energy Now energy assessment and implementing recommendations to improve the efficiency of its steam system.
Date: March 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Toxin studies using an integrated biophysical and structural biology approach. (open access)

Toxin studies using an integrated biophysical and structural biology approach.

Clostridial neurotoxins, such as botulinum and tetanus, are generally thought to invade neural cells through a process of high affinity binding mediated by gangliosides, internalization via endosome formation, and subsequent membrane penetration of the catalytic domain activated by a pH drop in the endosome. This surface recognition and internalization process is still not well understood with regard to what specific membrane features the toxins target, the intermolecular interactions between bound toxins, and the molecular conformational changes that occur as a result of pH lowering. In an effort to elucidate the mechanism of tetanus toxin binding and permeation through the membrane a simple yet representative model was developed that consisted of the ganglioside G{sub tlb} incorporated in a bilayer of cholesterol and DPPC (dipalmitoylphosphatidyl choline). The bilayers were stable over time yet sensitive towards the binding and activity of whole toxin. A liposome leakage study at constant pH as well as with a pH gradient, to mimic the processes of the endosome, was used to elucidate the effect of pH on the toxin's membrane binding and permeation capability. Topographic imaging of the membrane surface, via in situ tapping mode AFM, provided nanoscale characterization of the toxin's binding location and pore formation …
Date: March 1, 2005
Creator: Last, Julie A.; Schroeder, Anne E.; Slade, Andrea Lynn; Sasaki, Darryl Yoshio; Yip, Christopher M. (University of Toronto, Toronto, Ontario, Canada) & Schoeniger, Joseph S. (Sandia National Laboratories, Livermore, CA)
Object Type: Report
System: The UNT Digital Library
Ecological Monitoring and Compliance Program 2007 Report (open access)

Ecological Monitoring and Compliance Program 2007 Report

In accordance with U.S. Department of Energy (DOE) Order 450.1, 'Environmental Protection Program', the Office of the Assistant Manager for Environmental Management of the DOE, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) requires ecological monitoring and biological compliance support for activities and programs conducted at the Nevada Test Site (NTS). National Security Technologies, LLC (NSTec), Ecological Services has implemented the Ecological Monitoring and Compliance (EMAC) Program to provide this support. EMAC is designed to ensure compliance with applicable laws and regulations, delineate and define NTS ecosystems, and provide ecological information that can be used to predict and evaluate the potential impacts of proposed projects and programs on those ecosystems. This report summarizes the EMAC activities conducted by NSTec during calendar year 2007. Monitoring tasks during 2007 included eight program areas: (a) biological surveys, (b) desert tortoise compliance, (c) ecosystem mapping and data management, (d) sensitive plant monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat monitoring, (g) habitat restoration monitoring, and (h) biological monitoring at the Nonproliferation Test and Evaluation Complex (NPTEC). The following sections of this report describe work performed under these eight areas.
Date: March 1, 2008
Creator: Dennis Hansen, David Anderson, Derek Hall, Paul Greger, W. Kent Ostler
Object Type: Report
System: The UNT Digital Library
Study on the top quark pair production mechanism in 1.96 TeV proton-antiproton collisions (open access)

Study on the top quark pair production mechanism in 1.96 TeV proton-antiproton collisions

The study of the top quark pair production mechanism in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV is described. The main subjects are the measurements of the top quark pair production cross section, the top quark mass and a search for a new particle decaying to the top quark pair. The analyses are based on 1.9 fb{sup -1} of data collected by the Collider Detector at Fermilab (CDF) Run II experiment between March 2002 and May 2007, using the lepton+jets events. The measured top quark pair production cross section is 8.2 {+-} 0.5 (stat.) {+-} 0.8 (syst.) {+-} 0.5 (lum.) pb, which is slightly higher than the standard model prediction at the top mass of 175 GeV/c{sup 2}. The top quark mass is an important parameter in the standard model, and also in the experimental studies. The measured top quark mass if 171.6 {+-} 2.0 (stat.) {+-} 1.3(syst.) GeV/c{sup 2}. Finally, they report on a search for a new gauge boson decaying to t{bar t}, which interferes with the standard model gluon in the q{bar q} {yields} t{bar t} production process. They call such a hypothetical particle a 'Massive Gluon'. The observed t{bar t} invariant mass distribution is …
Date: March 1, 2008
Creator: Naganoma, Junji & U., /Waseda
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Conformal coating value/risk assessment for Sandia satellite programs. (open access)

Conformal coating value/risk assessment for Sandia satellite programs.

Conformal coatings are used in space applications on printed circuit board (PCB) assemblies primarily as a protective barrier against environmental contaminants. Such coatings have been used at Sandia for decades in satellite applications including the GPS satellite program. Recently, the value of conformal coating has been questioned because it is time consuming (requiring a 5-6 week schedule allowance) and delays due to difficulty of repairs and rework performed afterward are troublesome. In an effort to find opportunities where assembly time can be reduced, a review of the literature as well as discussions with satellite engineers both within and external to Sandia regarding the value of conformal coating was performed. Several sources on the value of conformal coating, the functions it performs, and on whether coatings are necessary and should be used at all were found, though nearly all were based on anecdotal information. The first section of this report, titled 'Conformal Coating for Space Applications', summarizes the results of an initial risk-value assessment of the conformal coating process for Sandia satellite programs based on information gathered. In the process of collecting information to perform the assessment, it was necessary to obtain a comprehensive understanding of the entire satellite box assembly …
Date: March 1, 2008
Creator: Russick, Edward Mark & Thayer, Gayle Echo
Object Type: Report
System: The UNT Digital Library