300 Area D4 Project 3rd Quarter Fiscal Year 2006 Building Completion Report (open access)

300 Area D4 Project 3rd Quarter Fiscal Year 2006 Building Completion Report

This report documents the deactivation, decontamination, decommissioning, and demolition of five buildings in the 300 Area of the Hanford Site. The D4 of these facilities included characterization, engineering, removal of hazardous and radiologically contaminated materials, equipment removal, utility disconnection, deactivation, decontamination, demolition of the structure, and stabilization or removal of the remaining slab and foundation as appropriate.
Date: September 25, 2006
Creator: Smith, D. S.
Object Type: Report
System: The UNT Digital Library
30th Actinide Separations Conference, PNNL-SA-50126 (open access)

30th Actinide Separations Conference, PNNL-SA-50126

Program booklet for the 30th Actinide Separations Conference. Contains agenda and abstracts for 27 poster and 38 oral presentations to be made during the 3-day meeting, May 23-25, 2006.
Date: May 25, 2006
Creator: Delegard, Calvin H.
Object Type: Article
System: The UNT Digital Library
Analysis Strategy of Powder Diffraction Data with 2-D Detector (open access)

Analysis Strategy of Powder Diffraction Data with 2-D Detector

To gain a clearer understanding of orientation and grain deformation of crystalline materials, x-ray powder diffraction has played an integral role in extracting three-dimensional structural information from one-dimensional diffraction patterns. Powder diffraction models identical geometry to the intersection of a normal right cone with a plane. The purpose of this paper is to develop a general expression defining the conic sections based on the geometry of a powder diffraction experiment. Applying the derived formulation of a diffraction arc to experimental data will give insight to the molecular and structural properties of the sample in question. Instead of using complex three-dimensional Euclidian geometry, we define the problem solving technique with a simpler two-dimensional transformation approach to arrive at the final equation describing the conic sections. Using the diffraction geometry parameters, we can use this equation to calibrate the diffractometer from the diffraction pattern of a known reference material, or to determine the crystalline lattice structure of the compound.
Date: January 25, 2006
Creator: Kumar, Abhik & /SLAC, SSRL
Object Type: Report
System: The UNT Digital Library
An analytical solution for transient gas flow in a multi-wellsystem (open access)

An analytical solution for transient gas flow in a multi-wellsystem

Soil vapor extraction (SVE) combined with air injectionprovides an efficient way for the cleanup of vadose zone contaminated byvolatile organic chemicals (VOCs). A successful design of an SVE system,however, relies on a good knowledge of the induced gas flow field in thevadose zone. Analytical solutions are available to help understand thegas flow field at steady-state. However, most SVE systems must pass atransient period before reaching steady (or quasi-steady) state and thelength of the period should be system-specific. This paper presents ananalytical solution for transient gas flow in a vadose zone withextraction and injection wells. The transient solution approaches thesteady-state solution as time increases. Calculations have shown that fora shallow well (screened in a depth of less than 10 m) in a vadose zonewith an air permeability of 1 darcy (10-12 m2) or larger, the systemreaches steady-state in just several hours. Decreasing the airpermeability or increasing the screen depth increases the time to reachsteady-state. In practical applications the transient solution may berelatively insignificant in an SVE design. However, the solution can beimportant in site characterization through pneumatic tests. A procedureis provided for applying the dimensionless solution in estimating airpermeability and air-filled porosity. An example is also given to use thetransient solution …
Date: May 25, 2006
Creator: Shan, Chao
Object Type: Article
System: The UNT Digital Library
Application of Imaging Plate to X-Ray Imaging and Spectroscopy in Laser Plasma Experiments (open access)

Application of Imaging Plate to X-Ray Imaging and Spectroscopy in Laser Plasma Experiments

We report recent progress of x-ray diagnostic techniques in laser plasma experiment with using imaging plates. Imaging plate is a photo-stimulable phosphor screen (BaF(Br0.85,10.15):Eu{sup 2+}) deposited on flexible metal or plastic substrate. We applied the imaging plate to x-ray microscopy in laser fusion experiment experiments. Self-emission x-ray images of imploded core were obtained successfully with using imaging plate and high magnification target mounted pinhole arrays. The imaging plates were applied also in ultra-intense laser experiment at the Rutherford Appleton Laboratory. Small samarium foil was irradiated by high intensity laser pulse from the Vulcan laser system. The k shell x-rays from the foil ({approx}40keV) was used as a line x-ray source for microscopic radiography. Performance of imaging plate on high-energy x-ray backlit radiography was demonstrated by imaging sinusoidal grooves of 6um amplitude on a Au foil. Detailed spectrum of k shell x-ray from Cu embedded foil target was successfully observed by fully coupling imaging plate with a highly ordered pyrolytic graphite crystal spectrometer. The performances of the imaging plates evaluated in actual laser plasma experiments will be presented.
Date: April 25, 2006
Creator: Izumi, N.; Snavely, R.; Gregori, G.; Koch, J. A.; Park, H. & Remington, B. A.
Object Type: Article
System: The UNT Digital Library
Astrophysical Radiation Hydrodynamics: The Prospects for Scaling (open access)

Astrophysical Radiation Hydrodynamics: The Prospects for Scaling

The general principles of scaling are discussed, followed by a survey of the important dimensionless parameters of fluid dynamics including radiation and magnetic fields, and of non-LTE spectroscopy. The values of the parameters are reviewed for a variety of astronomical and laboratory environments. It is found that parameters involving transport coefficients--the fluid and magnetic Reynolds numbers--have enormous values for the astronomical problems that are not reached in the lab. The parameters that measure the importance of radiation are also scarcely reached in the lab. This also means that the lab environments are much closer to LTE than the majority of astronomical examples. Some of the astronomical environments are more magnetically dominated than anything in the lab. The conclusion is that a good astronomical environment for simulation in a given lab experiment can be found, but that the reverse is much more difficult.
Date: May 25, 2006
Creator: Castor, J I
Object Type: Article
System: The UNT Digital Library
A Bayesian Analysis of Regularised Source Inversions in Gravitational Lensing (open access)

A Bayesian Analysis of Regularised Source Inversions in Gravitational Lensing

Strong gravitational lens systems with extended sources are of special interest because they provide additional constraints on the models of the lens systems. To use a gravitational lens system for measuring the Hubble constant, one would need to determine the lens potential and the source intensity distribution simultaneously. A linear inversion method to reconstruct a pixellated source distribution of a given lens potential model was introduced by Warren and Dye. In the inversion process, a regularization on the source intensity is often needed to ensure a successful inversion with a faithful resulting source. In this paper, we use Bayesian analysis to determine the optimal regularization constant (strength of regularization) of a given form of regularization and to objectively choose the optimal form of regularization given a selection of regularizations. We consider and compare quantitatively three different forms of regularization previously described in the literature for source inversions in gravitational lensing: zeroth-order, gradient and curvature. We use simulated data with the exact lens potential to demonstrate the method. We find that the preferred form of regularization depends on the nature of the source distribution.
Date: January 25, 2006
Creator: Suyu, Sherry H.; Marshall, P. J.; Hobson, M. P. & Blandford, R. D.
Object Type: Report
System: The UNT Digital Library
Best Angle to Orient Two Intersecting Lines (open access)

Best Angle to Orient Two Intersecting Lines

Fiducials in the form of intersecting straight lines are used to align the target in the final target chamber of the National Ignition Facility of Lawrence Livermore National Laboratory. One of the techniques used to locate these lines is the Hough transform. When two lines intersect at a 90 degree angle, it is tempting to orient the lines to horizontal and vertical directions. There are other possible angles at which the lines may be oriented. One question that arises while designing the fiducials is whether there is a preferred angle or range of angles that leads to higher accuracy. This work attempts to answer this question through detailed computer simulation.
Date: July 25, 2006
Creator: Awwal, A. S.; Ferguson, S. W. & Shull, P. B.
Object Type: Article
System: The UNT Digital Library
Bootstrapping One-Loop QCD Amplitudeswith General Helicities (open access)

Bootstrapping One-Loop QCD Amplitudeswith General Helicities

The recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD combines the unitarity method with loop-level on-shell recursion. For generic helicity configurations, the recursion relations may involve undetermined contributions from non-standard complex singularities or from large values of the shift parameter. Here we develop a strategy for sidestepping difficulties through use of pairs of recursion relations. To illustrate the strategy, we present sets of recursion relations needed for obtaining n-gluon amplitudes in QCD. We give a recursive solution for the one-loop n-gluon QCD amplitudes with three or four color-adjacent gluons of negative helicity and the remaining ones of positive helicity. We provide an explicit analytic formula for the QCD amplitude A{sub 6;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}), as well as numerical results for A{sub 7;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}), A{sub 8;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}, 8{sup +}), and A{sub 8;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup -}, 5{sup +}, 6{sup +}, 7{sup +}, 8{sup +}). We expect the on-shell bootstrap approach to have widespread applications to phenomenological studies at colliders.
Date: April 25, 2006
Creator: Berger, Carola F.; Bern, Zvi; Dixon, Lance J.; Forde, Darren & Kosower, David A.
Object Type: Report
System: The UNT Digital Library
Borehole Geologic Data for the 216-Z Crib Facilities, A Status of Data Assembled through the Hanford Borehole Geologic Information System (HBGIS) (open access)

Borehole Geologic Data for the 216-Z Crib Facilities, A Status of Data Assembled through the Hanford Borehole Geologic Information System (HBGIS)

The Pacific Northwest National Laboratory (PNNL) is assembling existing borehole geologic information to aid in determining the distribution and potential movement of contaminants released to the environment and to aid selection of remedial alternatives. This information is being assembled via the Hanford Borehole Geologic Information System (HBGIS), which is being developed as part of the Characterization of Systems Project, managed by PNNL, and the Remediation Decision Support Task of the Groundwater Remediation Project, managed by Fluor Hanford, Inc. The purpose of this particular study was to assemble the existing borehole geologic data pertaining to sediments underlying the 216-Z Crib Facilities and the Plutonium Finishing Plant Closure Zone. The primary objective for Fiscal Year 2006 was to assemble the data, complete log plots, and interpret the location of major geologic contacts for each major borehole in and around the primary disposal facilities that received carbon tetrachloride. To date, 154 boreholes located within or immediately adjacent to 19 of the 216-Z crib facilities have been incorporated into HBGIS. Borehole geologic information for the remaining three Z-crib facilities is either lacking (e.g. 216-Z-13, -14, and -15), or has been identified as a lesser priority to be incorporated at a later date.
Date: September 25, 2006
Creator: Last, George V.; Mackley, Rob D. & Lanigan, David C.
Object Type: Report
System: The UNT Digital Library
Broadband dielectric function of non-equilibrium warm dense gold (open access)

Broadband dielectric function of non-equilibrium warm dense gold

We report on the first single-state measurement of the broadband (450-800 nm) dielectric function of gold isochorically heated by a femtosecond laser pulse to energy densities of 10{sup 6}-10{sup 7} J/kg. A Drude and an inter-band component are clearly seen in the imaginary part of the dielectric function. The Drude component increases with energy density while the inter-band component shows both enhancement and red shift. This is in strong disagreement with predictions of a recent calculation of dielectric function based on limited k-point sampling.
Date: April 25, 2006
Creator: Ping, Y.; Hanson, D.; Koslow, I.; Ogitsu, T.; Prendergast, D.; Schwegler, E. et al.
Object Type: Article
System: The UNT Digital Library
Calculation of the Naval Long and Short Waste Package Three-Dimensional Thermal Interface Temperatures (open access)

Calculation of the Naval Long and Short Waste Package Three-Dimensional Thermal Interface Temperatures

The purpose of this calculation is to evaluate the thermal performance of the Naval Long and Naval Short spent nuclear fuel (SNF) waste packages (WP) in the repository emplacement drift. The scope of this calculation is limited to the determination of the temperature profiles upon the surfaces of the Naval Long and Short SNF waste package for up to 10,000 years of emplacement. The temperatures on the top of the outside surface of the naval canister are the thermal interfaces for the Naval Nuclear Propulsion Program (NNPP). The results of this calculation are intended to support Licensing Application design activities.
Date: October 25, 2006
Creator: Marr, H.
Object Type: Report
System: The UNT Digital Library
CH Packaging Program Guidance (open access)

CH Packaging Program Guidance

The purpose of this document is to provide the technical requirements for preparation for use, operation, inspection, and maintenance of a Transuranic Package TransporterModel II (TRUPACT-II), a HalfPACT shipping package, and directly related components. This document complies with the minimum requirements as specified in the TRUPACT-II Safety Analysis Report for Packaging (SARP), HalfPACT SARP, and U.S. Nuclear Regulatory Commission (NRC) Certificates of Compliance (C of C) 9218 and 9279, respectively. In the event of a conflict between this document and the SARP or C of C, the C of C shall govern. The C of Cs state: "each package must be prepared for shipment and operated in accordance with the procedures described in Chapter 7.0, Operating Procedures, of the application." They further state: "each package must be tested and maintained in accordance with the procedures described in Chapter 8.0, Acceptance Tests and Maintenance Program of the Application." Chapter 9.0 of the SARP charges the U.S. Department of Energy (DOE) or the Waste Isolation Pilot Plant| (WIPP) management and operating (M&O) contractor with assuring packaging is used in accordance with the requirements of the C of C. Because the packaging is NRC-approved, users need to be familiar with Title 10 Code …
Date: April 25, 2006
Creator: None, None
Object Type: Report
System: The UNT Digital Library
Characterization and Detection of Biological Weapons with Atomic Force Microscopy (open access)

Characterization and Detection of Biological Weapons with Atomic Force Microscopy

Critical gaps exist in our capabilities to rapidly characterize threat agents which could be used in attacks on facilities and military forces. DNA-based PCR and immunoassay-based techniques provide unique identification of species, strains and protein signatures of pathogens. However, differentiation between naturally occurring and weaponized bioagents and the identification of formulation signatures are beyond current technologies. One of the most effective and often the only definitive means to identify a threat agent is by its direct visualization. Atomic force microscopy (AFM) is a rapid imaging technique that covers the size range of most biothreat agents (several nanometers to tens of microns), is capable of resolving pathogen morphology and structure, and could be developed into a portable device for biological weapons (BW) field characterization. AFM can detect pathogens in aerosol, liquid, surface and soil samples while concomitantly acquiring their weaponization and threat agent digital signatures. BW morphological and structural signatures, including modifications to pathogen microstructural architecture and topology that occur during formulation and weaponization, provide the means for their differentiation from crude or purified unformulated agent, processing signatures, as well as assessment of their potential for dispersion, inhalation and environmental persistence. AFM visualization of pathogen morphology and architecture often provides valuable …
Date: September 25, 2006
Creator: Malkin, A J; Plomp, M; Leighton, T J & McPherson, A
Object Type: Article
System: The UNT Digital Library
Characterization of 200-UP-1 and 200-ZP-1 Operable Unit Aquifer Sediments and Batch Adsorption Distribution Coefficients for Contaminants of Concern--Fiscal Year 2006 Progress (open access)

Characterization of 200-UP-1 and 200-ZP-1 Operable Unit Aquifer Sediments and Batch Adsorption Distribution Coefficients for Contaminants of Concern--Fiscal Year 2006 Progress

A total of six core samples from 200-UP/ZP-1 OUs and two additional outcrop samples were characterized during FY2006 by PNNL. One sample (C4971) was identified as slough and not used, but the five other samples identified as intact core samples were used for further analyses. The C4977 sample is gravel-sandy silt and C4990 samples are fine-sandy silt from the Ringold formation. Although the sediments from these two boreholes have similar mineralogical composition, C4990 samples show higher values of Fe oxide content, clay/silt content, and surface area compared those in C4977. The measured Tc Kd values ranged 0–0.2 mg/L for both samples, while U(VI) Kd for C4990 (4.23 mg/L) is much higher than that for C4977 (0.76 mg/L). A key finding from the Kd measurements is that detailed sediment and pore water characterization is necessary to understand the variation in Kd values seen in the empirical batch tests. Without the ancillary characterization of the sediments and pore waters, one might form misleading interpretations of the mechanisms that control the Kd values. Thus, physical, geochemical, and hydrological characterization of the sediments and pore waters should be conducted to increase our understanding of the site-specific Kd measurements. More details for methods and results …
Date: September 25, 2006
Creator: Um, Wooyong & Serne, R. Jeffrey
Object Type: Report
System: The UNT Digital Library
Characterization of Suspect Fuel Rod Pieces from the 105 K West Basin (open access)

Characterization of Suspect Fuel Rod Pieces from the 105 K West Basin

This report provides physical and radiochemical characterization results from examinations and laboratory analyses performed on {approx}0.55-inch diameter rod pieces found in the 105 K West (KW) Basin that were suspected to be from nuclear reactor fuel. The characterization results will be used to establish the technical basis for adding this material to the contents of one of the final Multi-Canister Overpacks (MCOs) that will be loaded out of the KW Basin in late FY2006 or at a later time depending on project priorities. Fifteen fuel rod pieces were found during the clean out of the KW Basin. Based on lack of specific credentials, documentation, or obvious serial numbers, none of the items could be positively identified nor could their sources or compositions be described. Item weights and dimensions measured in the KW Basin indicated densities consistent with the suspect fuel rods containing uranium dioxide (UO2), uranium metal, or being empty. Extensive review of the Hanford Site technical literature led to the postulation that these pieces likely were irradiated test fuel prepared to support of the development of the Hanford ''New Production Reactor'', later called N Reactor. To obtain definitive data on the composition of the suspect fuel, 4 representative fuel …
Date: July 25, 2006
Creator: Delegard, Calvin H.; Schmidt, Andrew J.; Pool, Karl N. & Thornton, Brenda M.
Object Type: Report
System: The UNT Digital Library
Climate Forcings and Climate Sensitivities Diagnosed from Coupled Climate Model Integrations (open access)

Climate Forcings and Climate Sensitivities Diagnosed from Coupled Climate Model Integrations

A simple technique is proposed for calculating global mean climate forcing from transient integrations of coupled Atmosphere Ocean General Circulation Models (AOGCMs). This 'climate forcing' differs from the conventionally defined radiative forcing as it includes semi-direct effects that account for certain short timescale responses in the troposphere. Firstly, we calculate a climate feedback term from reported values of 2 x CO{sub 2} radiative forcing and surface temperature time series from 70-year simulations by twenty AOGCMs. In these simulations carbon dioxide is increased by 1%/year. The derived climate feedback agrees well with values that we diagnose from equilibrium climate change experiments of slab-ocean versions of the same models. These climate feedback terms are associated with the fast, quasi-linear response of lapse rate, clouds, water vapor and albedo to global surface temperature changes. The importance of the feedbacks is gauged by their impact on the radiative fluxes at the top of the atmosphere. We find partial compensation between longwave and shortwave feedback terms that lessens the inter-model differences in the equilibrium climate sensitivity. There is also some indication that the AOGCMs overestimate the strength of the positive longwave feedback. These feedback terms are then used to infer the shortwave and longwave time …
Date: July 25, 2006
Creator: de F. Forster, Piers & Taylor, Karl E.
Object Type: Article
System: The UNT Digital Library
Confirmatory Survey Results for the Reactor Building Dome Upper Surfaces, Rancho Saco Nuclear Generating Station (open access)

Confirmatory Survey Results for the Reactor Building Dome Upper Surfaces, Rancho Saco Nuclear Generating Station

Results from a confirmatory survey of the upper structural surfaces of the Reactor Building Dome at the Rancho Seco Nuclear Generating Station (RSNGS) performed by the Oak Ridge Institute for Science and Education for the NRC. Also includes results of interlaboratory comparison analyses on several archived soil samples that would be provided by RSNGS personnel. The confirmatory surveys were performed on June 7 and 8, 2006.
Date: October 25, 2006
Creator: Adams, Wade C.
Object Type: Report
System: The UNT Digital Library
Defect reduction in (11-20) a-plane GaN by two step epitaxiallateral overgrowth (open access)

Defect reduction in (11-20) a-plane GaN by two step epitaxiallateral overgrowth

We report a two-step growth method to obtain uniformly coalesced epitaxial lateral overgrown a-plane GaN by metal-organic chemical vapor deposition (MOCVD). By obtaining a large wing height to width aspect ratio in the first step followed by enhanced lateral growth in the second step via controlling the growth temperature, we reduced the tilt angle between the advancing Ga-polar and N-polar wings for improved properties. Transmission electron microscopy (TEM) showed that the threading dislocation density in the wing area was 1.0 x 10{sup 8}cm{sup -2}, more than two orders of magnitude lower than that in the window area (4.2 x 10{sup 10} cm{sup -2}). However, a high density of basal stacking faults, 1.2 x 10{sup 4} cm{sup -1}, was still observed in the wing area. Near field scanning optical microscopy (NSOM) at room temperature revealed that the luminescence was mainly from the wing regions with very little contribution from the windows and meeting fronts. These observations suggest that due to significant reduction of threading dislocations radiative recombination is enhanced in the wings.
Date: November 25, 2006
Creator: Ni, X.; Ozgur, U.; Fu, Y.; Biyikii, N.; Morkoc, H. & Liliental-Weber, Z.
Object Type: Article
System: The UNT Digital Library
Delineation of Waters of the United States for Lawrence Livermore National Laboratory, Site 300 (open access)

Delineation of Waters of the United States for Lawrence Livermore National Laboratory, Site 300

This report presents the results of a delineation of waters of the United States, including wetlands, for Lawrence Livermore National Laboratory's Site 300 in Alameda and San Joaquin Counties, California. Jones & Stokes mapped vegetation at Site 300 in August, 2001, using Global Positioning System (GPS) data recorders to collect point locations and to record linear features and map unit polygons. We identified wetlands boundaries in the field on the basis of the plant community present. We returned to collect additional information on wetland soils on July 3, 2002. Forty-six wetlands were identified, with a total area of 3.482 hectares (8.605 acres). The wetlands include vernal pools, freshwater seeps, and seasonal ponds. Wetlands appearing to meet the criteria for federal jurisdictional total 1.776 hectares (4.388 acres). A delineation map is presented and a table is provided with information on the type, size, characteristic plant species of each wetland, and a preliminary jurisdictional assessment.
Date: September 25, 2006
Creator: Preston, R E
Object Type: Report
System: The UNT Digital Library
Development and Testing of a Groundwater Management Model for the Faultless Underground Nuclear Test, Central Nevada Test Area (open access)

Development and Testing of a Groundwater Management Model for the Faultless Underground Nuclear Test, Central Nevada Test Area

This document describes the development and application of a user-friendly and efficient groundwater management model of the Central Nevada Test Area (CNTA) and surrounding areas that will allow the U.S. Department of Energy and state personnel to evaluate the impact of future proposed scenarios. The management model consists of a simple hydrologic model within an interactive groundwater management framework. This framework is based on an object user interface that was developed by the U.S. Geological Survey and has been used by the Desert Research Institute researchers and others to couple disparate environmental resource models, manage the necessary temporal and spatial data, and evaluate model results for management decision making. This framework was modified and applied to the CNTA and surrounding Hot Creek Valley. The utility of the management model was demonstrated through the application of hypothetical future scenarios including mineral mining, regional expansion of agriculture, geothermal energy production, and export of water to large urban areas outside the region. While the results from some of the scenarios indicated potential impacts to the region near CNTA and others did not, together they demonstrate the usefulness of the management tool for managers who need to evaluate the impact proposed changes in groundwater …
Date: January 25, 2006
Creator: Boyle, Douglas P.; Lamorey, Gregg; Bassett, Scott; Pohll, Greg & Chapman, Jenny
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION (open access)

DEVELOPMENT OF A CO2 SEQUESTRATION MODULE BY INTEGRATING MINERAL ACTIVATION AND AQUEOUS CARBONATION

Mineral carbonation provides a potential option for the long-term storage of carbon dioxide. Serpentine has been chosen as the feedstock mineral, due to its abundance and availability. However, the relatively low reactivity of serpentine has warranted research into physical and chemical treatments that have been shown to greatly increase its reactivity. The use of sulfuric acid as an accelerating medium for the removal of magnesium from serpentine has recently been investigated. In addition to the challenges presented by the dissolution of serpentine, another challenge is the subsequent carbonation of the magnesium ions. A stable hydration sphere for the magnesium ion reduces the carbonation kinetics by obstructing the formation of the carbonation products. Accordingly, this research has evaluated the solubility of carbon dioxide in aqueous solution, the interaction between the dissociation products of carbon dioxide, and the carbonation potential of the magnesium ion.
Date: March 25, 2006
Creator: Alexander, George; Maroto-Valer, M. Mercedes; Aksoy, Parvana & Schobert, Harold
Object Type: Report
System: The UNT Digital Library
Development of Pulse Position Modulation/Optical CDMA (PPM/O-CDMA) for Gb/s Fiber Optic Networking (open access)

Development of Pulse Position Modulation/Optical CDMA (PPM/O-CDMA) for Gb/s Fiber Optic Networking

Pulse position modulation (PPM) in lasercom systems is known to provide potential advantages over other modulation schemes. [1]. In PPM, a periodic time frame is established and data is transmitted by placing a pulse in any one of several subintervals (or ''slots'') within each frame. In PPM/O-CDMA all users use the same frame structure and each transmits its unique address code in place of the PPM pulse. The advantage of PPM as a pulsed signal format is that (1) a single pulse can transmit multiple bits during each frame; (2) decoding (determining which subinterval contains the pulse) is by comparison rather than threshold tests (as in on-off-keying); (3) each user transmits in only a small fraction of the frame, hence the multi-access interference (MAI) of any user statistically spreads over the entire frame time, reducing the chance of overlap with any other user; and (4) under an average power constraint, increasing frame time increases the peak pulse power (i.e., PPM trades average power for peak power). The most straightforward approach to implementing PPM/O-CDMA data modulator inserts the PPM pulse modulation first, then imposes the O-CDMA coding. A pulsed PPM modulator converts bits (words) into pulse positions. In the case of …
Date: May 25, 2006
Creator: Mendez, A. J.; Hernandez, V. J.; Gagliardi, R. M.; Bennett, C. V. & Lennon, W. J.
Object Type: Article
System: The UNT Digital Library
Direct Injection Compressed Ignition Diesel Automotive Technology Education GATE Program (open access)

Direct Injection Compressed Ignition Diesel Automotive Technology Education GATE Program

The underlying goal of this project was to provide multi-disciplinary engineering training for graduate students in the area of internal combustion engines, specifically in direct injection compression ignition engines. The program was designed to educate highly qualified engineers and scientists that will seek to overcome technological barriers preventing the development and production of cost-effective high-efficiency vehicles for the US. market. Further, these highly qualified engineers and scientists will foster an educational process to train a future workforce of automotive engineering professionals who are knowledgeable about and have experience in developing and commercializing critical advanced automotive technologies. Eight objectives were defined to accomplish this goal: (1) Develop an interdisciplinary internal combustion engine curriculum emphasizing direct injected combustion ignited diesel engines. (2) Encourage and promote interdisciplinary interaction of the faculty. (3) Offer a Ph.D. degree in internal combustion engines based upon an interdisciplinary curriculum. (4) Promote strong interaction with industry, develop a sense of responsibility with industry and pursue a self sustaining program. (5) Establish collaborative arrangements and network universities active in internal combustion engine study. (6) Further Enhance a First Class educational facility. (7) Establish ''off-campus'' M.S. and Ph.D. engine programs of study at various industrial sites. (8) Extend and Enhance …
Date: September 25, 2006
Creator: Anderson, Carl L.
Object Type: Report
System: The UNT Digital Library