Language

REMOVAL OF TECHNETIUM 99 FROM THE EFFLUENT TREATMENT FACILITY (ETF) BASIN 44 USING PUROLITE A-530E & REILLEX HPQ & SYBRON IONAC SR-7 ION EXCHANGE RESINS (open access)

REMOVAL OF TECHNETIUM 99 FROM THE EFFLUENT TREATMENT FACILITY (ETF) BASIN 44 USING PUROLITE A-530E & REILLEX HPQ & SYBRON IONAC SR-7 ION EXCHANGE RESINS

This report documents the laboratory testing and analyses as directed under the test plan, RPP-20407. The overall goal of this task was to evaluate and compare candidate anion exchange resins for their capacity to remove Technetium-99 from Basin 44 Reverse Osmosis reject stream. The candidate resins evaluated were Purolite A-530E, Reillex HPQ, and Sybron IONAC SR-7.
Date: October 29, 2004
Creator: JB, DUNCAN
Object Type: Report
System: The UNT Digital Library
LIQUID EFFLUENT RETENTION FACILITY (LERF) BASIN 42 STUDIES (open access)

LIQUID EFFLUENT RETENTION FACILITY (LERF) BASIN 42 STUDIES

This report documents laboratory results obtained under test plan RPP-21533 for samples submitted by the Effluent Treatment Facility (ETF) from the Liquid Effluent Retention Facility (LERF) Basin 42 (Reference 1). The LERF Basin 42 contains process condensate (PC) from the 242-A Evaporator and landfill leachate. The ETF processes one PC campaign approximately every 12 to 18 months. A typical PC campaign volume can range from 1.5 to 2.5 million gallons. During the September 2003 ETF Basin 42 processing campaign, a recurring problem with 'gelatinous buildup' on the outlet filters from 60A-TK-I (surge tank) was observed (Figure 1). This buildup appeared on the filters after the contents of the surge tank were adjusted to a pH of between 5 and 6 using sulfuric acid. Biological activity in the PC feed was suspected to be the cause of the gelatinous material. Due to this buildup, the filters (10 {micro}m CUNO) required daily change out to maintain process throughput.
Date: October 29, 2004
Creator: JB, DUNCAN
Object Type: Report
System: The UNT Digital Library
POST-PROCESSING ANALYSIS FOR THC SEEPAGE (open access)

POST-PROCESSING ANALYSIS FOR THC SEEPAGE

This report describes the selection of water compositions for the total system performance assessment (TSPA) model of results from the thermal-hydrological-chemical (THC) seepage model documented in ''Drift-Scale THC Seepage Model'' (BSC 2004 [DIRS 169856]). The selection has been conducted in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2004 [DIRS 171334]). This technical work plan (TWP) was prepared in accordance with AP-2.27Q, ''Planning for Science Activities''. Section 1.2.3 of the TWP describes planning information pertaining to the technical scope, content, and management of this report. The post-processing analysis for THC seepage (THC-PPA) documented in this report provides a methodology for evaluating the near-field compositions of water and gas around a typical waste emplacement drift as these relate to the chemistry of seepage, if any, into the drift. The THC-PPA inherits the conceptual basis of the THC seepage model, but is an independently developed process. The relationship between the post-processing analysis and other closely related models, together with their main functions in providing seepage chemistry information for the Total System Performance Assessment for the License Application (TSPA-LA), are illustrated in Figure 1-1. The …
Date: September 29, 2004
Creator: SUN, Y.
Object Type: Report
System: The UNT Digital Library
Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors (open access)

Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful technique for studying bi-molecular interactions at the atomic scale. Our NMR lab is involved in the identification of small molecules, or ligands that bind to target protein receptors, such as tetanus (TeNT) and botulinum (BoNT) neurotoxins, anthrax proteins and HLA-DR10 receptors on non-Hodgkin's lymphoma cancer cells. Once low affinity binders are identified, they can be linked together to produce multidentate synthetic high affinity ligands (SHALs) that have very high specificity for their target protein receptors. An important nanotechnology application for SHALs is their use in the development of robust chemical sensors or biochips for the detection of pathogen proteins in environmental samples or body fluids. Here, we describe a recently developed NMR competition assay based on transferred nuclear Overhauser effect spectroscopy (trNOESY) that enables the identification of sets of ligands that bind to the same site, or a different site, on the surface of TeNT fragment C (TetC) than a known ''marker'' ligand, doxorubicin. Using this assay, we can identify the optimal pairs of ligands to be linked together for creating detection reagents, as well as estimate the relative binding constants for ligands competing for the same site.
Date: April 29, 2004
Creator: Cosman, M; Krishnan, V V & Balhorn, R
Object Type: Book
System: The UNT Digital Library
RP-5 Renewable Energy Efficiency Project (open access)

RP-5 Renewable Energy Efficiency Project

This is the sixth quarterly technical report for the RP-5 Renewable Energy Efficiency Project. The report summarizes the work progress, effort and activities that took place during the period from October 1, 2003 through December 31, 2003. The report has been prepared in accordance with the Department of Energy (DOE) Guidelines. In coordination with the DOE, IEUA has revised the original Cooperative Agreement to reflect the actual and current project scope of work. The original Agreement statement of work (SOW) included conceptual and preliminary equipment and systems, which were further evaluated for feasibility and suitability for the project. As a result, some of the equipment was taken out of the project scope. In response to questions from the DOE, IEUA has submitted a summary report on the Organic Rankine Cycle (ORC) secondary power generation units for availability and suitability for this project and associated safety concerns pointed out by the DOE. IEUA has awarded the consulting engineering contract to Parsons Water and Infrastructure, Inc. to provide the project's design and construction services. The project's pre-design kickoff meeting was held at IEUA's headquarters on December 11, 2003. IEUA has submitted a proposal for a grant offered by California Energy Commission (CEC) …
Date: January 29, 2004
Creator: Clifton, Neil; Whitman, Eliza Jane & Zughbi, Jamal A.
Object Type: Report
System: The UNT Digital Library
Smoothing of Military Mirrors by Novel Surface Alloying and Melting Technique (open access)

Smoothing of Military Mirrors by Novel Surface Alloying and Melting Technique

None
Date: July 29, 2004
Creator: Williams, J.M. (BronteK Delta Corp.)
Object Type: Report
System: The UNT Digital Library
An Assessment of Future Demands for and Benefits of Public Transit Srevices in Tennessee (open access)

An Assessment of Future Demands for and Benefits of Public Transit Srevices in Tennessee

This report documents results from a study carried out by Oak Ridge National Laboratory and the University of Tennessee at Knoxville for the Office of Public Transportation, Tennessee Department of Transportation. The study team was tasked with developing a process and a supporting methodology for estimating the benefits accruing to the State from the operation of state supported public transit services. The team was also tasked with developing forecasts of the future demands for these State supported transit services at five year intervals through the year 2020, broken down where possible to the local transit system level. Separate ridership benefits and forecasts were also requested for the State's urban and rural transit operations. Tennessee's public transit systems are subsidized to a degree by taxpayers. It is therefore in the public interest that assessments of the benefits of such systems be carried out at intervals, to determine how they are contributing to the well-being of the state's population. For some population groups within the State of Tennessee these transit services have become essential as a means of gaining access to workplaces and job training centers, to educational and health care facilities, as well as to shops, social functions and recreational sites.
Date: April 29, 2004
Creator: Southworth, F.
Object Type: Report
System: The UNT Digital Library
Comparison of Varve and 14C Chronologies from Steel Lake, Minnesota, USA (open access)

Comparison of Varve and 14C Chronologies from Steel Lake, Minnesota, USA

Annually laminated sediments (varves) offer an effective means of acquiring high-quality paleoenvironmental records. However, the strength of a varve chronology can be compromised by a number of factors, such as missing varves, ambiguous laminations, and human counting error. We assess the quality of a varve chronology for the last three millennia from Steel Lake, Minnesota, through comparisons with nine AMS {sup 14}C dates on terrestrial plant macrofossils from the same core. These comparisons revealed an overall 8.4% discrepancy, primarily because of missing/uncountable varves within two stratigraphic intervals characterized by low carbonate concentrations and obscure laminations. Application of appropriate correction factors to these two intervals results in excellent agreement between the varve and {sup 14}C chronologies. These results, together with other varve studies, demonstrate that an independent age-determination method, such as {sup 14}C dating, is usually necessary to verify, and potentially correct, varve chronologies.
Date: December 29, 2004
Creator: Tian, J; Brown, T A & Hu, F S
Object Type: Article
System: The UNT Digital Library
Cluster Form Factor Calculation in the Ab Initio No-Core Shell Model (open access)

Cluster Form Factor Calculation in the Ab Initio No-Core Shell Model

None
Date: July 29, 2004
Creator: Navratil, P
Object Type: Article
System: The UNT Digital Library
Influences on the Height of the Stable Boundary Layer as seen in Large-Eddy Simulations (open access)

Influences on the Height of the Stable Boundary Layer as seen in Large-Eddy Simulations

Numerical weather prediction (NWP) models and atmospheric dispersion models rely on parameterizations of planetary boundary layer height. In the case of a stable boundary layer, errors in boundary layer height estimation can result in gross errors in boundary-layer evolution and in prediction of turbulent mixing within the boundary layer. We use large-eddy simulations (LES) of moderately stable boundary layers to characterize the effects of various physical processes on stable boundary layers. The stable boundary layer height is assumed to be a function of surface friction velocity, geostrophic wind, Monin-Obukhov length, and the strength of the temperature inversion atop the stable boundary layer. This temperature inversion induces gravity waves with a frequency determined by the strength of the temperature inversion.
Date: March 29, 2004
Creator: Kosovic, B & Lundquist, J K
Object Type: Article
System: The UNT Digital Library
Timing is Everything:The Boon and Bane of 14C Geochronology (open access)

Timing is Everything:The Boon and Bane of 14C Geochronology

There are underappreciated limitations of the conversion of {sup 14}C-ages to the fixed, calendrical time-scale that bear directly upon our understanding of the dynamic climate system, or the relationship between the collapse of one civilization and it's neighbor's. In this paper we present a quantitative assessment of the limits of {sup 14}C-geochronology and calibration onto the absolute calendrical time-scale over the Holocene. We take into account not only the inherent limitations of the {sup 14}C-calendar calibration curve, but also analytical uncertainties.
Date: October 29, 2004
Creator: Guilderson, T; Guilderson, T; Reimer, P J & Brown, T
Object Type: Article
System: The UNT Digital Library
The Response of Plant Carbohydrates to Elevated CO2: What Have We Learnt From Face Studies? (open access)

The Response of Plant Carbohydrates to Elevated CO2: What Have We Learnt From Face Studies?

Atmospheric CO{sub 2} concentration ([CO{sub 2}]) is expected to rise from a current level of 372 {micro}mol mol{sup -1} to about 550 {micro}mol mol{sup -1} by the middle of the century (Prentice 2001). Accumulation of foliar carbohydrates is one of the most pronounced and universal changes observed in the leaves of C{sub 3} plants grown at elevated [CO{sub 2}] (Drake et al 1997). Carbohydrates are the product of photosynthetic cells and the substrate for sink metabolism. However, carbohydrates are not just substrates, changes in the composition and pool size of foliar carbohydrates have the potential to communicate source-sink balance and a role for carbohydrates in the regulation of the expression of many plant genes is well established (Koch 1996). Importantly, carbohydrate feedback is thought to be the mechanism through which long-term exposure to elevated [CO{sub 2}] leads to a reduction in carboxylation capacity (Rogers et a1 199S, Long et al 2004). Foliar sugar content has recently been linked to an increased susceptibility of soybeans to insect herbivory (Hamilton et al submitted). In addition increases in the C:N ratio of leaf litter of plants grown at elevated [CO{sub 2}] has been implicated in negative feedbacks on ecosystem productivity (Oechel et al …
Date: August 29, 2004
Creator: Rogers, A.; Ainsworth, E. A.; Bernacchi, C. J.; Gibon, Y.; Stitt, M. & Long, S. P.
Object Type: Article
System: The UNT Digital Library
FINAL CLOSURE PLAN SURFACE IMPOUNDMENTS CLOSURE, SITE 300 (open access)

FINAL CLOSURE PLAN SURFACE IMPOUNDMENTS CLOSURE, SITE 300

Lawrence Livermore National Laboratory of the University of California (LLNL) operates two Class II surface impoundments that store wastewater that is discharged from a number of buildings located on the Site 300 Facility (Site 300). The wastewater is the by-product of explosives processing. Reduction in the volume of water discharged from these buildings over the past several years has significantly reduced the wastewater storage needs. In addition, the impoundments were constructed in 1984, and the high-density polyethylene (HDPE) geomembrane liners are nearing the end of their service life. The purpose of this project is to clean close the surface impoundments and provide new wastewater storage using portable, above ground storage tanks at six locations. The tanks will be installed prior to closure of the impoundments and will include heaters for allowing evaporation during relatively cool weather. Golder Associates (Golder) has prepared this Final Closure Plan (Closure Plan) on behalf of LLNL to address construction associated with the clean closure of the impoundments. This Closure Plan complies with State Water Resources Control Board (SWRCB) Section 21400 of the California Code of Regulations Title 27 (27 CCR {section}21400). As required by these regulations and guidance, this Plan provides the following information: (1) …
Date: September 29, 2004
Creator: Lane, J E; Scott, J E & Mathews, S E
Object Type: Report
System: The UNT Digital Library
Studies of laser-driven radiative blast waves (open access)

Studies of laser-driven radiative blast waves

We have performed two sets of experiments looking at laser-driven radiating blast waves. In one set of experiments the effect of a drive laser's passage through a background gas on the hydrodynamical evolution of blast waves was examined. It was found that the laser's passage heats a channel in the gas, creating a region where a portion of the blast wave front had an increased velocity, leading to the formation of a bump-like protrusion on the blast wave. The second set of experiments involved the use of regularly spaced wire arrays to induce perturbations on a blast wave surface. The decay of these perturbations as a function of time was measured for various wave number perturbations and found to be in good agreement with theoretical predictions.
Date: April 29, 2004
Creator: Edwards, M J; Hansen, J; Edens, A; Ditmire, T; Adams, R; Rambo, P et al.
Object Type: Article
System: The UNT Digital Library
Recent Site-Wide Transport Modeling Related to the Carbon Tetrachloride Plume at the Hanford Site (open access)

Recent Site-Wide Transport Modeling Related to the Carbon Tetrachloride Plume at the Hanford Site

Carbon tetrachloride transport in the unconfined aquifer system at the Hanford Site has been the subject of follow-on studies since the Carbon Tetrachloride Innovative Treatment Remediation Demonstration (ITRD) Program was completed in FY 2002. These scoping analyses were undertaken to provide support for strategic planning and guidance for the more robust modeling needed to obtain a final record of decision (ROD) for the carbon tetrachloride plume in the 200 West Area. This report documents the technical approach and the results of these follow-on, site-wide scale-modeling efforts. The existing site-wide groundwater model was used in this effort. The work extended that performed as part of the ITRD modeling study in which a 200 West Area scale submodel was developed to examine arrival concentrations at an arbitrary boundary between the 200 E and 200 W areas. These scoping analyses extended the analysis to predict the arrival of the carbon tetrachloride plume at the Columbia River. The results of these analyses illustrate the importance of developing field-scale estimates of natural attenuation parameters, abiotic degradation rate and soil/water equilibrium sorption coefficient, for carbon tetrachloride. With these parameters set to zero, carbon tetrachloride concentrations will exceed the compliance limit of 5 {micro}g/L outside the 200 …
Date: September 29, 2004
Creator: Bergeron, Marcel P. & Cole, C R.
Object Type: Report
System: The UNT Digital Library
Field-Scale Migration of 99Tc and 129I at the Nevada Test Site (open access)

Field-Scale Migration of 99Tc and 129I at the Nevada Test Site

The groundwater at the Nevada Test Site (NTS) contains many long-lived radionuclides, including {sup 99}Tc (technetium) and {sup 129}I (iodine), as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. We synthesized a body of data collected on the distribution of {sup 99}Tc and {sup 129}I in groundwater to assess their migration at NTS, at field scales over distances of hundreds of meters and for durations up to forty years and under hydrogeologic conditions very similar to the proposed geological repository at Yucca Mountain. The results of our study show that Tc does not necessarily exist as a mobile and conservative species TcO{sub 4}{sup -}, as has been commonly assumed. This conclusion is corroborated by recent in situ redox potential measurements, which show that groundwaters at multiple locations of the NTS are not oxidizing, and mobility of reduced Tc species (TcO{sub 2} {center_dot} nH{sub 2}O) is greatly decreased. Speciation of iodine and its associated reactivity is also complex in the groundwater at the NTS, and its effect on the mobility of iodine should be the subject of future studies.
Date: March 29, 2004
Creator: Hu, Q & Smith, D K
Object Type: Article
System: The UNT Digital Library
Technology Base 2004 Report on the Ultrasonic Calibration Test Phantom (open access)

Technology Base 2004 Report on the Ultrasonic Calibration Test Phantom

We designed and built a phantom consisting of vertical wires maintained under tension to be used as an ultrasonic test, calibration, and reconstruction object for the LLNL annular array scanner known as the KCI scanner. We provide a description of the phantom, present some example data sets, and preliminary reconstructions. The project goals are to design and build a reconfigurable ultrasonic phantom for the KCI scanner. Use it to collect well characterized data under controlled conditions for use as ''canonical data sets'' in testing and evaluating new inversion algorithms. The non-destructive evaluation (NDE) of objects and media of interest to LLNL/DOE/DOD is an essential part of LLNL's mission. Many NDE situations have put demands beyond the scope of the current suite of imaging algorithms. As new algorithms and codes come on line, they must be evaluated on well characterized phantoms. The Ultrasonic Calibration Test Phantom provides such a data set.
Date: September 29, 2004
Creator: Lehman, S K; Fisher, K A; Werve, M & Chambers, D H
Object Type: Report
System: The UNT Digital Library
Solid State NMR Measurements for Preliminary Lifetime Assessments in gamma-Irradiated and Thermally Aged Siloxane Elastomers (open access)

Solid State NMR Measurements for Preliminary Lifetime Assessments in gamma-Irradiated and Thermally Aged Siloxane Elastomers

Siloxanes have a wide variety of applications throughout the aerospace industry which take advantage of their exceptional insulating and adhesive properties and general resilience. They also offer a wide range of tailorable engineering properties with changes in composition and filler content. They are, however, subject to degradation in radiatively and thermally harsh environments. We are using solid state nuclear magnetic resonance techniques to investigate changes in network and interfacial structure in siloxane elastomers and their correlations to changes in engineering performance in a series of degraded materials. NMR parameters such as transverse ( T{sub 2}) relaxation times, cross relaxation rates, and residual dipolar coupling constants provide excellent probes of changes crosslink density and motional dynamics of the polymers caused by multi-mechanism degradation. The results of NMR studies on aged siloxanes are being used in conjunction with other mechanical tests to provide insight into component failure and degradation kinetics necessary for preliminary lifetime assessments of these materials as well as into the structure-property relationships of the polymers. NMR and MRI results obtained both from high resolution NMR spectrometers as well as low resolution benchtop NMR screening tools will be presented.
Date: November 29, 2004
Creator: Chinn, S C; Herberg, J L; Sawvel, A M & Maxwell, R S
Object Type: Report
System: The UNT Digital Library
Initial results of a positron tomograph for prostate imaging (open access)

Initial results of a positron tomograph for prostate imaging

We present the status and initial images of a positrontomograph for prostate imaging that centers a patient between a pair ofexternal curved detector banks (ellipse: 45 cm minor, 70 cm major axis).The distance between detector banks adjusts to allow patient access andto position the detectors as closely as possible for maximum sensitivitywith patients of various sizes. Each bank is composed of two axial rowsof 20 CTI PET Systems HR+ block detectors for a total of 80 modules inthe camera. Compared to an ECAT HR PET system operating in 3D mode, ourcamera uses about one-quarter the number of detectors and hasapproximately the same sensitivity for a central point source, becauseour detectors are close to the patient. The individual detectors areangled in the plane to point towards the prostate to minimize resolutiondegradation in that region. The detectors are read out by modified CTIdata acquisition electronics. We have completed construction of thegantry and electronics, have developed detector calibration and dataacquisition software, and are taking coincidence data. We demonstratethat we can clearly visualize a "prostate" in a simple phantom.Reconstructed images of two phantoms are shown.
Date: November 29, 2004
Creator: Huber, J. S.; Choong, W. S.; Moses, W. W.; Qi, J.; Hu, J.; Wang, G. C. et al.
Object Type: Article
System: The UNT Digital Library
Determining flow, recharge, and vadose zonedrainage in anunconfined aquifer from groundwater strontium isotope measurements, PascoBasin, WA (open access)

Determining flow, recharge, and vadose zonedrainage in anunconfined aquifer from groundwater strontium isotope measurements, PascoBasin, WA

Strontium isotope compositions (87Sr/86Sr) measured in groundwater samples from 273 wells in the Pasco Basin unconfined aquifer below the Hanford Site show large and systematic variations that provide constraints on groundwater recharge, weathering rates of the aquifer host rocks, communication between unconfined and deeper confined aquifers, and vadose zone-groundwater interaction. The impact of millions of cubic meters of wastewater discharged to the vadose zone (103-105 times higher than ambient drainage) shows up strikingly on maps of groundwater 87Sr/86Sr. Extensive access through the many groundwater monitoring wells at the site allows for an unprecedented opportunity to evaluate the strontium geochemistry of a major aquifer, hosted primarily in unconsolidated sediments, and relate it to both long term properties and recent disturbances. Groundwater 87Sr/86Sr increases systematically from 0.707 to 0.712 from west to east across the Hanford Site, in the general direction of groundwater flow, as a result of addition of Sr from the weathering of aquifer sediments and from diffuse drainage through the vadose zone. The lower 87Sr/86Sr groundwater reflects recharge waters that have acquired Sr from Columbia River Basalts. Based on a steady-state model of Sr reactive transport and drainage, there is an average natural drainage flux of 0-1.4 mm/yr near …
Date: June 29, 2004
Creator: Singleton, Michael J.; Maher, Katharine; DePaulo, Donald J.; Conrad, Mark E. & Dresel, P. Evan
Object Type: Article
System: The UNT Digital Library
KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS (open access)

KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

This report covers the second year of this three-year research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict concentrations of all reactants and major product species (H{sub 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the second year of the project we completed the STSR test SB-26203 (275-343 h on stream), which was initiated during the first year of the project, and another STSR test (SB-28603 lasting 341 h). Since the inception of the project we completed 3 STSR tests, and evaluated catalyst under 25 different sets of process conditions. A precipitated iron catalyst obtained from Ruhrchemie AG (Oberhausen-Holten, Germany) was used in all tests. This catalyst was used initially in commercial fixed bed reactors at Sasol in South Africa. Also, during the second year we performed a qualitative analysis of experimental data from all three STSR tests. …
Date: September 29, 2004
Creator: Bukur, Dragomir B.
Object Type: Report
System: The UNT Digital Library
Development of Novel Water-Gas Shift Membrane Reactor (open access)

Development of Novel Water-Gas Shift Membrane Reactor

This report summarizes the objectives, technical barrier, approach, and accomplishments for the development of a novel water-gas-shift (WGS) membrane reactor for hydrogen enhancement and CO reduction. We have synthesized novel CO{sub 2}-selective membranes with high CO{sub 2} permeabilities and high CO{sub 2}/H{sub 2} and CO{sub 2}/CO selectivities by incorporating amino groups in polymer networks. We have also developed a one-dimensional non-isothermal model for the countercurrent WGS membrane reactor. The modeling results have shown that H{sub 2} enhancement (>99.6% H{sub 2} for the steam reforming of methane and >54% H{sub 2} for the autothermal reforming of gasoline with air on a dry basis) via CO{sub 2} removal and CO reduction to 10 ppm or lower are achievable for synthesis gases. With this model, we have elucidated the effects of system parameters, including CO{sub 2}/H{sub 2} selectivity, CO{sub 2} permeability, sweep/feed flow rate ratio, feed temperature, sweep temperature, feed pressure, catalyst activity, and feed CO concentration, on the membrane reactor performance. Based on the modeling study using the membrane data obtained, we showed the feasibility of achieving H{sub 2} enhancement via CO{sub 2} removal, CO reduction to {le} 10 ppm, and high H{sub 2} recovery. Using the membrane synthesized, we have obtained …
Date: December 29, 2004
Creator: Ho, W. S. Winston
Object Type: Report
System: The UNT Digital Library
Advanced Membrane Filtration Technology for Cost Effective Recovery of Fresh Water from Oil & Gas Produced Brine (open access)

Advanced Membrane Filtration Technology for Cost Effective Recovery of Fresh Water from Oil & Gas Produced Brine

Produced water is a major waste generated at the oil and natural gas wells in the state of Texas. This water could be a possible source of new fresh water to meet the growing demands of the state after treatment and purification. Treatment of brine generated in oil fields or produced water with an ultrafiltration membranes were the subject of this thesis. The characterization of ultrafiltration membranes for oil and suspended solids removal of produced water, coupled with the reverse osmosis (RO) desalination of brine were studied on lab size membrane testing equipment and a field size testing unit to test whether a viable membrane system could be used to treat produced water. Oil and suspended solids were evaluated using turbidity and oil in water measurements taken periodically. The research considered the effect of pressure and flow rate on membrane performance of produced water treatment of three commercially available membranes for oily water. The study also analyzed the flux through the membrane and any effect it had on membrane performance. The research showed that an ultrafiltration membrane provided turbidity removal of over 99% and oil removal of 78% for the produced water samples. The results indicated that the ultrafiltration membranes …
Date: September 29, 2004
Creator: Burnett, David B.
Object Type: Report
System: The UNT Digital Library
Heat Pump Water Heater Durabliltiy Testing - Phase II (open access)

Heat Pump Water Heater Durabliltiy Testing - Phase II

Ten heat pump water heaters (HPWH) were placed in an environmentally controlled test facility and run through a durability test program of approximately 7300 duty cycles (actual cycles accumulated ranged from 6640 to 8324 for the ten units). Five of the units were upgraded integral types (HPWH mounted on storage tank, no pump) from the same manufacturer as those tested in our first durability program in 2001 (Baxter and Linkous, 2002). The other five were ''add-on'' type units (HPWH with circulation pump plumbed to a separate storage tank) from another manufacturer. This durability test was designed to represent approximately 7-10 years of normal operation to meet the hot water needs of a residence. The integral units operated without incident apart from two control board failures. Both of these were caused by inadvertent exposure to very hot and humid (>135 F dry bulb and >120 F dew point) conditions that occurred due to a test loop failure. It is not likely that any residential water heater would be installed where such conditions were expected so these failures are not considered a long-term reliability concern. Two of the integral HPWHs featured a condensate management system (CMS) option that effectively eliminated any need …
Date: May 29, 2004
Creator: Baxter, VAND.
Object Type: Report
System: The UNT Digital Library