Alternative Fuels and Chemicals From Synthesis Gas Technical Progress Report: Number 30 (open access)

Alternative Fuels and Chemicals From Synthesis Gas Technical Progress Report: Number 30

The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.
Date: March 31, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Calendar Year 2001 Groundwater Monitoring Report, U.S. Department of Energy Y-12 National Security Complex, Oak Ridge, Tennessee (open access)

Calendar Year 2001 Groundwater Monitoring Report, U.S. Department of Energy Y-12 National Security Complex, Oak Ridge, Tennessee

This report contains the groundwater and surface water monitoring data that were obtained during calendar year (CY) 2001 at the U.S. Department of Energy (DOE) Y-12 National Security Complex (hereafter referenced as Y-12) in Oak Ridge, Tennessee. The monitoring data were obtained from groundwater and surface water sampling locations within three hydrogeologic regimes at Y-12. The following sections of this report provide details regarding the CY 2001 groundwater and surface water monitoring activities in the Bear Creek, East Fork, and Chestnut Ridge Regimes. Section 2 identifies the sampling locations in each hydrogeologic regime and the corresponding sampling frequency during CY 2001, along with the associated quality assurance/quality control (QA/QC) sampling. Section 3 describes groundwater and surface water sample collection and Section 4 identifies the field measurements and laboratory analytes for each sampling location. Section 5 outlines the data management protocols and data quality objectives (DQOs). Section 6 describes the groundwater elevation monitoring in each regime during CY 2001 and Section 7 lists the documents cited for more detailed operational, regulatory, and technical information.
Date: March 31, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
CALLA ENERGY BIOMASS COFIRING PROJECT (open access)

CALLA ENERGY BIOMASS COFIRING PROJECT

The Calla Energy Biomass Project, to be located in Estill County, Kentucky is to be conducted in two phases. The objective of Phase I is to evaluate the technical and economic feasibility of cofiring biomass-based gasification fuel-gas in a power generation boiler. Waste coal fines are to be evaluated as the cofired fuel. The project is based on the use of commercially available technology for feeding and gas cleanup that would be suitable for deployment in municipal, large industrial and utility applications. Define a combustion system for the biomass gasification-based fuel-gas capable of stable, low-NOx combustion over the full range of gaseous fuel mixtures, with low carbon monoxide emissions and turndown capabilities suitable for large-scale power generation applications. The objective for Phase II is to design, install and demonstrate the combined gasification and combustion system in a large-scale, long-term cofiring operation to promote acceptance and utilization of indirect biomass cofiring technology for large-scale power generation applications. During this Performance Period work efforts focused on completion of the Topical Report, summarizing the design and techno-economic study of the project's feasibility. GTI received supplemental authorization A002 from DOE contracts for additional work to be performed under Phase I that will further extend …
Date: March 31, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS FUELS (open access)

CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS FUELS

Proposed activities for quarter 7 (12/15/01-3/14/2002): (1) Incorporation of moisture model into PCGC2 code. Parametric study of moisture effects on flame structure and pollutants emissions in cofiring of coal and Liter Biomass (LB) (Task 4); (2) Use the ash tracer method to determine the combustion efficiency and comparison it to results from gas analysis (Task 2); (3) Effect of swirl on combustion performance (Task 2); (4) Completion of the proposed modifications to the gasifier setup (Task 3); (5) Calibration of the Gas Chromatograph (GC) used for measuring the product gas species (Task 3); and (6) To obtain temperature profiles for different fuels under different operating conditions in the fixed bed gasifier (Task 3).
Date: March 31, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR (open access)

DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

The objectives of this report period were to complete the development of the Gas Generator design, which was done; fabricate and test of the non-polluting unique power turbine drive gas Gas Generator, which has been postponed. Focus during this report period has been to complete the brazing and bonding necessary to fabricate the Gas Generator hardware, continue making preparations for fabricating and testing the Gas Generator, and continuing the fabrication of the Gas Generator hardware and ancillary hardware in preparation for the test program. Fabrication is more than 95% complete and is expected to conclude in early May 2002. the test schedule was affected by relocation of the testing to another test supplier. The target test date for hot fire testing is now not earlier than June 15, 2002.
Date: March 31, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Direct Energy Conversion Fission Reactor Progress Report: January-March 2002 (open access)

Direct Energy Conversion Fission Reactor Progress Report: January-March 2002

Direct energy conversion is the only potential means for producing electrical energy from a fission reactor without the Carnot efficiency limitations. This project was undertaken by Sandia National Laboratories, Los Alamos National Laboratories, The University of Florida, Texas A&M University and General Atomics to explore the possibilities of direct energy conversion. Other means of producing electrical energy from a fission reactor, without any moving parts, are also within the statement of proposed work. This report documents the efforts of General Atomics. Sandia National Laboratories, the lead laboratory, provides overall project reporting and documentation. The highlights of this reporting period are: (1) Cooling of the vapor core reactor and the MHD generator was incorporated into the Vapor Core Reactor model using standard heat transfer calculation methods. (2) Fission product removal, previously modeled as independent systems for each class of fission product, was incorporated into the overall fuel recycle loop of the Vapor Core Reactor. The model showed that the circulating activity levels are quite low. (3) Material distribution calculations were made for the ''pom-pom'' style cathode for the Fission Electric Cell. Use of a pom-pom cathode will eliminate the problem of hoop stress in the thin spherical cathode caused by the …
Date: March 31, 2002
Creator: Brown, L. C.
Object Type: Report
System: The UNT Digital Library
Exploitation and Optimization of Reservoir Performance in Hunton Formation, Oklahoma: Final Report, Budget Period 1 (open access)

Exploitation and Optimization of Reservoir Performance in Hunton Formation, Oklahoma: Final Report, Budget Period 1

The West Carney Field in Lincoln County, Oklahoma is one of few newly discovered oil fields in Oklahoma. Although profitable, the field exhibits several unusual characteristics. These include decreasing water-oil ratios, decreasing gas-oil ratios, decreasing bottomhole pressures during shut-ins in some wells, and transient behavior for water production in many wells. This report explains the unusual characteristics of West Carney Field based on detailed geological and engineering analyses. We propose a geological history that explains the presence of mobile water and oil in the reservoir. The combination of matrix and fractures in the reservoir explains the reservoir's flow behavior. We confirm our hypothesis by matching observed performance with a simulated model and develop procedures for correlating core data to log data so that the analysis can be extended to other, similar fields where the core coverage may be limited.
Date: March 31, 2002
Creator: Kelkar, Mohan
Object Type: Report
System: The UNT Digital Library
Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas (open access)

Field Demonstration of Carbon Dioxide Miscible Flooding in the Lansing-Kansas City Formation, Central Kansas

Progress is reported for the period from January 1, 2002 to March 31, 2002. Technical design and budget for a larger (60-acre, 24.3 ha) CO2 demonstration project are being reviewed by the US DOE for approval. While this review process is being conducted, work is proceeding on well testing to obtain reservoir properties and on the VIP reservoir simulation model to improve model prediction and better understand the controls that certain parameters exert on predicted performance. In addition, evaluation of the economics of commercial application in the surrounding area was performed. In a meeting on January 14, 2002 the possibility of staging the demonstration, starting with a 10-acre sub-pattern flood was raised and the decision made to investigate this plan in detail. The influence of carbon dioxide on oil properties and the influence of binary interaction parameters (BIP) used in the VIP simulator were investigated. VIP calculated swelling factors are in good agreement with published values up to 65% mole-fraction CO2. Swelling factor and saturated liquid density are relatively independent of the BIP over the range of BIPs used (0.08-0.15) up to 65% mole-fraction CO2. Assuming a CO2 EOR recovery rate projected as being most likely by current modeling, commercial …
Date: March 31, 2002
Creator: Byrnes, Alan; Willhite, G. Paul; Green, Don; Dubois, Martin; Pancake, Richard; Carr, Timothy et al.
Object Type: Report
System: The UNT Digital Library
High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs Quarterly Report (open access)

High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs Quarterly Report

This report outlines progress in the second quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. A three-dimensional streamline simulator, developed at Stanford University, has been modified in order to use analytical one-dimensional dispersion-free solutions to multicomponent gas injection processes. The use of analytical one-dimensional solutions in combination with streamline simulation is demonstrated to speedup compositional simulations of miscible gas injection processes by orders of magnitude compared to a conventional finite difference simulator. Two-dimensional and three-dimensional examples are reported to demonstrate the potential of this technology. Finally, the assumptions of the approach and possible extensions to include the effects of gravity are discussed.
Date: March 31, 2002
Creator: Orr, Franklin M., Jr.
Object Type: Report
System: The UNT Digital Library
Instrumentation Development, Measurement and Performance Evaluation of Environmental Technologies (open access)

Instrumentation Development, Measurement and Performance Evaluation of Environmental Technologies

This report covers the following topics: Characterization of Heavy Metals and Radionuclides; Development of Tools for Long-term Monitoring; Hanford Tank Waste Chemistry; Environmental Control Device Testing; and Process Monitoring and Control of Toxic Organics.
Date: March 31, 2002
Creator: Plodinec, J.
Object Type: Report
System: The UNT Digital Library
LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES (open access)

LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and testing of Planar Single Cells. This period has continued to address the problem of making dense 1/2 to 5 {micro}m thick dense layers on porous substrates (the cathode LSM). Our current status is that we are making structures of 2-5 cm{sup 2} in area, which consist of either dense YSZ or CGO infiltrated into a 2-5 {micro}m thick 50% porous layer made of either nanoncrystalline CGO or YSZ powder. This composite structure coats a macroporous cathode or anode; which serves as the structural element of the bi-layer structure. These structures are being tested as SOFC elements. A number of structures have been evaluated both as symmetrical and as button cell configuration. Results of this testing indicates that the cathodes contribute the most to cell losses for temperatures below 750 C. In this investigation different cathode materials were studied using impedance spectroscopy of symmetric cells and IV characteristics of anode supported fuel cells. Cathode materials studied included La{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (LSCF), La{sub 0.7}Sr{sub 0.2}MnO{sub 3} (LSM), Pr{sub 0.8}Sr{sub 0.2}Fe{sub 0.8}O{sub 3} (PSCF), Sm{sub 0.8}Sr{sub 0.2}Co{sub 0.2}Fe{sub 0.8}O{sub 3} (SSCF), …
Date: March 31, 2002
Creator: Anderson, Harlan U.; Dogan, Fatih & Petrovsky, Vladimir
Object Type: Report
System: The UNT Digital Library
Modeling Coal Matrix Shrinkage and Differential Swelling with CO2 Injection for Enhanced Coalbed Methane Recovery and Carbon Sequestration Applications (open access)

Modeling Coal Matrix Shrinkage and Differential Swelling with CO2 Injection for Enhanced Coalbed Methane Recovery and Carbon Sequestration Applications

Matrix shrinkage and swelling can cause profound changes in porosity and permeability of coalbed methane reservoirs during depletion or when under CO{sub 2} injection processes, with significant implication for primary or enhanced methane recovery. Two models that are used to describe these effects are discussed. The first was developed by Advanced Resources International (ARI) and published in 1990 by Sawyer, et al. The second model was published by Palmer and Mansoori in 1996. This paper shows that the two provide equivalent results for most applications. However, their differences in formulation cause each to have relative advantages and disadvantages under certain circumstances. Specifically, the former appears superior for undersaturated coalbed methane reservoirs while the latter would be better if a case is found where matrix swelling is strongly disproportional to gas concentration. Since its presentation in 1996, the Palmer and Mansoori model has justifiably received much critical praise. However, the model developed by ARI for the COMET reservoir simulation program has been in use since 1990, and has significant advantages in certain settings. A review of data published by Levine in 1996 reveals that carbon dioxide causes a greater degree of coal matrix swelling compared to methane, even when measured on …
Date: March 31, 2002
Creator: Pekot, L. J. & Reeves, S. R.
Object Type: Report
System: The UNT Digital Library
New architectures for integrated photoelectrochemical systems. Final report, Sept. 1998 - Dec. 2001 (open access)

New architectures for integrated photoelectrochemical systems. Final report, Sept. 1998 - Dec. 2001

During the three year grant period, significant progress has been made toward the accomplishment of each of the goals outlined in the original proposal. The budget proposed for the project was also expended fully, as originally projected. In accord with these objectives, we have prepared an array of new macromolecules and supramolecular aggregates in which a light-sensitive organic group initiates long range photoinduced electron transfer in this designed heterogeneous environment. In doing so, we have developed several new synthetic methodologies for accurate spatial definition of these polymeric arrays on a nanometer to micrometer scale. We have used these integrated materials to define the photophysical principles that control vectorial energy and electron migration over distances that are large compared with the dimensions of most small molecules. By attaching these same molecules to the surface of a metal or semiconductor electrode, we have obtained chemically modified surfaces that function as efficient vehicles for conversion of incident photons to chemical or electrical energy. Thus, we have investigated: (1) the synthesis and characterization of new polymeric and supramolecular arrays for directional electron transfer; (2) new techniques for optical imaging in self-assembled monolayers on metals (mostly gold); and (3) fundamental principles that govern long range …
Date: March 31, 2002
Creator: Fox, Marye Anne
Object Type: Report
System: The UNT Digital Library
RESEARCH ON CARBON PRODUCTS FROM COAL USING AN EXTRACTIVE PROCESS (open access)

RESEARCH ON CARBON PRODUCTS FROM COAL USING AN EXTRACTIVE PROCESS

This report presents the results of a one-year effort directed at the exploration of the use of coal as a feedstock for a variety of industrially-relevant carbon products. The work was basically divided into three focus areas. The first area dealt with the acquisition of laboratory equipment to aid in the analysis and characterization of both the raw coal and the coal-derived feedstocks. Improvements were also made on the coal-extraction pilot plant which will now allow larger quantities of feedstock to be produced. Mass and energy balances were also performed on the pilot plant in an attempt to evaluate the scale-up potential of the process. The second focus area dealt with exploring hydrogenation conditions specifically aimed at testing several less-expensive candidate hydrogen-donor solvents. Through a process of filtration and vacuum distillation, viable pitch products were produced and evaluated. Moreover, a recycle solvent was also isolated so that the overall solvent balance in the system could be maintained. The effect of variables such as gas pressure and gas atmosphere were evaluated. The pitch product was analyzed and showed low ash content, reasonable yield, good coking value and a coke with anisotropic optical texture. A unique plot of coke yield vs. pitch …
Date: March 31, 2002
Creator: Stansberry, Peter G.; Stiller, Alfred H.; Zondlo, John W.; Chen, Chong; Bland, Brian & Fenton, David
Object Type: Report
System: The UNT Digital Library
Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation (open access)

Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

This report summarizes the work performed by Honeywell during the January 2002 to March 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. For this reporting period the following activities have been carried out: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} System-level performance model was created {lg_bullet} Dynamic control models are being developed {lg_bullet} Mechanical properties of candidate heat exchanger materials were investigated {lg_bullet} SOFC performance mapping as a function of flow rate and pressure was completed
Date: March 31, 2002
Creator: Minh, Nguyen
Object Type: Report
System: The UNT Digital Library
STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS (open access)

STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

Solid oxide fuel cells (SOFCs) are the future of energy production in America. They offer great promise as a clean and efficient process for directly converting chemical energy to electricity while providing significant environmental benefits (they produce negligible hydrocarbons, CO, or NO{sub x} and, as a result of their high efficiency, produce about one-third less CO{sub 2} per kilowatt hour than internal combustion engines). Unfortunately, the current SOFC technology, based on a stabilized zirconia electrolyte, must operate in the region of 1000 C to avoid unacceptably high ohmic losses. These high temperatures demand (a) specialized (expensive) materials for the fuel cell interconnects and insulation, (b) time to heat up to the operating temperature and (c) energy input to arrive at the operating temperature. Therefore, if fuel cells could be designed to give a reasonable power output at low to intermediate temperatures tremendous benefits may be accrued. At low temperatures, in particular, it becomes feasible to use ferritic steel for interconnects instead of expensive and brittle ceramic materials such as those based on LaCrO{sub 3}. In addition, sealing the fuel cell becomes easier and more reliable; rapid startup is facilitated; thermal stresses (e.g., those caused by thermal expansion mismatches) are reduced; …
Date: March 31, 2002
Creator: Wachsman, Eric D. & Duncan, Keith L.
Object Type: Report
System: The UNT Digital Library
UTSI/CFFF MHD PROGRAM COMPLETION AND RELATED ACTIVITY (open access)

UTSI/CFFF MHD PROGRAM COMPLETION AND RELATED ACTIVITY

Maintenance work on the DOE CFFF facility and other related government property is no longer authorized under this contract in accordance with the DOE-UT Settlement Agreement. Environmental remediation preservation of the facility continued. Government property has been transferred to UTSI as owner which frees up many items for proper disposal. Actions are underway to dispose of other wastes, and control pests and water at the DOE CFFF. Groundwater remediation activities as mandated by the Tennessee Department of Environment and Conservation (TDEC) continued throughout the quarter. A contract was awarded to an environmental consulting company to drill and sample three additional groundwater wells adjacent to the CFFF property. A report on this activity, with results of the sample analysis, has been sent to the TDEC.
Date: March 31, 2002
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Very high power THz radiation at Jefferson Lab (open access)

Very high power THz radiation at Jefferson Lab

We report the production of high power (20 watts average, {approx};1 Megawatt peak) broadband THz light based on coherent emission from relativistic electrons. We describe the source, presenting theoretical calculations and their experimental verification. For clarity we compare this source with one based on ultrafast laser techniques, and in fact the radiation has qualities closely analogous to that produced by such sources, namely that it is spatially coherent, and comprises short duration pulses with transform-limited spectral content. In contrast to conventional THz radiation, however, the intensity is many orders of magnitude greater due to the relativistic enhancement.
Date: March 31, 2002
Creator: Carr, G. L.; Martin, Michael C.; McKinney, Wayne R.; Jordan, K.; Neil, George R. & Williams, G. P.
Object Type: Article
System: The UNT Digital Library
A comparison of equilibrium and non-equilibrium cycle methods for Na-cooled ATW system. (open access)

A comparison of equilibrium and non-equilibrium cycle methods for Na-cooled ATW system.

An equilibrium cycle method, embodied in the REBUS-3[1] code system, has generally been used in conventional fast reactor design activities. The equilibrium cycle method provides an efficient approach for modeling reactor system, compared to the more traditional non-equilibrium cycle fuel management calculation approach. Recently, the equilibrium analysis method has been utilized for designing Accelerator Transmutation of Waste (ATW)[2,3,4] cores, in which a scattered-reloading fuel management scheme is used. Compared with the conventional fast reactors, the ATW core is significantly different in several aspects since its main mission is to incinerate the transuranic (TRU) fuels. The high burnup non-fertile fuel has large variations in composition and reactivity during its lifetime. Furthermore, a relatively short cycle length is utilized in the ATW design to limit the potentially large reactivity swing over a cycle, and consequently 7 or 8-batch fuel management is usually assumed for a high fuel burnup. The validity of the equilibrium analysis method for the ATW core, therefore, needed to be verified. The main objective of this paper is to assess the validity of the equilibrium analysis method for a Na-cooled ATW core[4], which is an alternative core design of the ATW system under development.
Date: March 30, 2002
Creator: Kim, Y.; Hill, R. N. & Taiwo, T. A.
Object Type: Article
System: The UNT Digital Library
Initial Development of a Continuous Emission Monitor for Dioxins (open access)

Initial Development of a Continuous Emission Monitor for Dioxins

Under contract DE-AC26-98FT-40370, SRI International has completed the third phase of a planned three-phase effort to develop a laboratory prototype continuous emission monitor (CEM) for dioxins and furans generated during the incineration of waste materials at DOE remediation sites. The project was initiated on July 29, 1998 with the technical effort completed in October 2001. During this research effort, SRI has made numerous improvements in our jet-REMPI instrument. These improvements have involved characterization and optimization of the molecular cooling in the gas jet, implementation of a custom-fabricated, four pulsed valve assembly, new data acquisition and display software, and preliminary development of a wavelength and mass calibration approach. We have also measured the REMPI excitation spectra of numerous organic compounds that are likely to be present in the exhaust stream of a waste incinerator. These spectra must be well characterized in the laboratory to understand any potential interferences that might arise when monitoring for dioxin and furan congeners. Our results to date continue to validate the original concept of using jet-REMPI as the detection method in a dioxin CEM. Using only commercial components with minor modifications, we have already demonstrated a detection sensitivity in the low ppt range with sufficient chemical …
Date: March 30, 2002
Creator: Coggiola, Michael J.; Oser, Harald; Faris, Gregory W. & Crosley, David R.
Object Type: Report
System: The UNT Digital Library
Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation and Recycle of Sodium Hydroxide and Sodium Nitrate (open access)

Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation and Recycle of Sodium Hydroxide and Sodium Nitrate

This research has focused on new liquid-liquid extraction chemistry applicable to separation of major sodium salts from alkaline tank waste. It was the overall goal to provide the scientific foundation upon which the feasibility of liquid-liquid extraction chemistry for bulk reduction of the volume of tank waste can be evaluated. Sodium hydroxide represented the initial test case and primary focus. It is a primary component of the waste1 and has the most value for recycle. A full explanation of the relevance of this research to USDOE Environmental Management needs will be given in the Relevance, Impact, and Technology Transfer section below. It should be noted that this effort was predicated on the need for sodium removal primarily from low-activity waste, whereas evolving needs have shifted attention to volume reduction of the high-activity waste. The results of the research to date apply to both applications, though treatment of high-activity wastes raises new questions that will be addressed in the renewal period. Toward understanding the extractive chemistry of sodium hydroxide and other sodium salts, it was the intent to identify candidate extractants and determine their applicable basic properties regarding selectivity, efficiency, speciation, and structure. A hierarchical strategy was to be employed in …
Date: March 30, 2002
Creator: Moyer, Bruce A.; Marchand, Alan P.; Bonnesen, Peter V.; Bryan, Jeffrey C. & Haverlock, Tamara J.
Object Type: Report
System: The UNT Digital Library
SURFACE-ALTERED ZEOLITES AS PERMEABLE BARRIERS FOR IN SITU TREATMENT OF CONTAMINATED GROUNDWATER (open access)

SURFACE-ALTERED ZEOLITES AS PERMEABLE BARRIERS FOR IN SITU TREATMENT OF CONTAMINATED GROUNDWATER

None
Date: March 30, 2002
Creator: Bowman, Robert S.; Zhang, Pengfei; Tao, Xian; Johnson, Richard L. & Wolf, Douglas
Object Type: Report
System: The UNT Digital Library
Africa: U.S. Foreign Assistance Issues (open access)

Africa: U.S. Foreign Assistance Issues

This report discusses the issue of U.S. economic assistance to sub-Saharan Africa, highlighting the importance of continued assistance in light of U.S. national security and also various U.S.-led efforts to promote reform amongst African citizens themselves. U.S. assistance finds its way to Africa through a variety of channels, including the USAID-administered DA program, food aid programs, and indirect aid provided through international financial institutions and the United Nations.
Date: March 29, 2002
Creator: Copson, Raymond W.
Object Type: Report
System: The UNT Digital Library
Attenuation of P-Waves by Wave-Induced Fluid Flow (open access)

Attenuation of P-Waves by Wave-Induced Fluid Flow

Analytical expressions for three P-wave attenuation mechanisms in rocks are given and numerically-compared. The mechanisms are: (1) Biot loss, in which flow occurs at the scale of the wavelength between the peaks and troughs of a P wave; (2) squirt loss, in which flow occurs at the grain scale between microcracks the grains and the adjacent pores; and (3) mesoscopic loss, in which flow occurs at intermediate scales between the various lithological bodies that are present in an averaging volume of earth material. Each mechanism is of importance over different frequency bands. Typically, Biot loss is only important at the highest of ultrasonic frequencies (> 1 MHz), squirt-loss (when it occurs) is important in the range of 10 kHz to 1 MHz, while mesoscale loss dominates at the lower frequencies (<10 kHz) employed in seismology.
Date: March 29, 2002
Creator: Pride, S R & Berryman, J G
Object Type: Article
System: The UNT Digital Library