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Hydrogen Storage Properties of Magnesium Base Nanostructured Composite Materials (open access)

Hydrogen Storage Properties of Magnesium Base Nanostructured Composite Materials

In this work, nanostructured composite materials have been synthesized using the mechanical alloying process. The new materials produced have been investigated by X-ray diffraction (XRD), transition electron microscope (TEM), scanning electron microscope (SEM) and electron energy dispersion spectrum (EDS) for their phase compositions, crystal structure, grain size, particle morphology and the distribution of catalyst element. Hydrogen storage capacities and the hydriding-dehydriding kinetics of the new materials have been measured at different temperatures using a Sieverts apparatus. It is observed that mechanical alloying accelerates the hydrogenation kinetics of the magnesium based materials at low temperature, but a high temperature must be provided to release the absorbed hydrogen from the hydrided magnesium based materials. It is believed that the dehydriding temperature is largely controlled by the thermodynamic configuration of magnesium hydride. Doping Mg-Ni nano/amorphous composite materials with lanthanum reduces the hydriding and dehydriding temperature. Although the stability of MgH2 can not be easily reduced by ball milling alone, the results suggest the thermodynamic properties of Mg-Ni nano/amorphous composite materials can be alternated by additives such as La or other effective elements. Further investigation toward understanding the mechanism of additives will be rewarded.
Date: April 30, 2004
Creator: AU, M
Object Type: Article
System: The UNT Digital Library
Analysis of Homogeneous Charge Compression Ignition (HCCI) Engines for Cogeneration Applications (open access)

Analysis of Homogeneous Charge Compression Ignition (HCCI) Engines for Cogeneration Applications

This paper presents an evaluation of the applicability of Homogeneous Charge Compression Ignition Engines (HCCI) for small-scale cogeneration (less than 1 MWe) in comparison to five previously analyzed prime movers. The five comparator prime movers include stoichiometric spark-ignited (SI) engines, lean burn SI engines, diesel engines, microturbines and fuel cells. The investigated option, HCCI engines, is a relatively new type of engine that has some fundamental differences with respect to other prime movers. Here, the prime movers are compared by calculating electric and heating efficiency, fuel consumption, nitrogen oxide (NOx) emissions and capital and fuel cost. Two cases are analyzed. In Case 1, the cogeneration facility requires combined power and heating. In Case 2, the requirement is for power and chilling. The results show that the HCCI engines closely approach the very high fuel utilization efficiency of diesel engines without the high emissions of NOx and the expensive diesel fuel. HCCI engines offer a new alternative for cogeneration that provides a unique combination of low cost, high efficiency, low emissions and flexibility in operating temperatures that can be optimally tuned for cogeneration systems. HCCI engines are the most efficient technology that meets the oncoming 2007 CARB NOx standards for cogeneration …
Date: April 30, 2004
Creator: Aceves, S; Martinez-Frias, J & Reistad, G
Object Type: Article
System: The UNT Digital Library
Hydrogen Storage in metal-modified single-walled carbon nanotubes (open access)

Hydrogen Storage in metal-modified single-walled carbon nanotubes

It has been known for over thirty years that potassium-intercalated graphites can readily adsorb and desorb hydrogen at {approx}1 wt% at 77 K. These levels are much higher than can be attained in pure graphite, owing to a larger thermodynamic enthalpy of adsorption. This increased enthalpy may allow hydrogen sorption at higher temperatures. Potassium has other beneficial effects that enable the design of a new material: (a) Increased adsorption enthalpy in potassium-intercalated graphite compared to pure graphite reduces the pressure and increases the temperature required for a given fractional coverage of hydrogen adsorption. We expect the same effects in potassium-intercalated SWNTs. (b) As an intercalant, potassium separates c-axis planes in graphite. Potassium also separates the individual tubes of SWNTs ropes producing swelling and increased surface area. Increased surface area provides more adsorption sites, giving a proportionately higher capacity. The temperature of adsorption depends on the enthalpy of adsorption. The characteristic temperature is roughly the adsorption enthalpy divided by Boltzmann's constant, k{sub B}. For the high hydrogen storage capacity of SWNTs to be achieved at room temperature, it is necessary to increase the enthalpy of adsorption. Our goal for this project was to use metal modifications to the carbon surface of …
Date: April 30, 2004
Creator: Ahn, Dr.
Object Type: Report
System: The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 106, No. 26, Ed. 1 Friday, April 30, 2004 (open access)

Altus Times (Altus, Okla.), Vol. 106, No. 26, Ed. 1 Friday, April 30, 2004

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: April 30, 2004
Creator: Andrews, Mike
Object Type: Newspaper
System: The Gateway to Oklahoma History
Effects of Ammonium Molybdophosphate (AMP) on Strontium, Actinides, and RCRA Metals in SRS Simulated Waste (open access)

Effects of Ammonium Molybdophosphate (AMP) on Strontium, Actinides, and RCRA Metals in SRS Simulated Waste

High Level Waste samples contain elevated concentrations of radioactive cesium requiring marked dilution of the waste to facilitate handling in non-shielded facilities. The authors developed a sample treatment protocol, using ammonium molybdophosphate (AMP) to remove sufficient cesium to allow handling of the samples with minimal dilution. The sample treatment protocol includes the following steps: pH adjust the sample to the range of 0.01 to 1.0 M acidity; mix 30 mL of acidified sample with 40-60 mg of AMP; cap and shake the mixture for 30-60 seconds; filter AMP from the liquid using 0.45 PTFE syringe filters; and send filtrate directly forward for analysis. To develop the method, SRTC performed a series of tests with three different salt solutions designed to determine the propensity of ammonium molybdophosphate (AMP) to bind some of the common analytes such as the actinides (Pu, Am, Np, U), strontium, or the metals (Ag, As, Ba, Cd, Cr, Hg, Pb, Se) regulated by the Resource Conservation Recovery Act (RCRA). SRTC also examined relevant literature to summarize reported interactions between AMP and other elements.
Date: April 30, 2004
Creator: BARNES, MARKJ
Object Type: Report
System: The UNT Digital Library
Gas Turbine Reheat Using In-Situ Combustion (open access)

Gas Turbine Reheat Using In-Situ Combustion

Gas turbine reheat is a well-known technique for increasing the power output of gas turbine, as well as the efficiency in combined cycle operation with higher heat recovery inlet temperatures. The technique also could allow development of an advanced high efficiency turbine with an additional stage, but without a higher inlet temperature. A novel reheat approach, with fuel added via internal passages in turbine airfoils, has been proposed [1]. This avoids the bulky and possible high-NOx discrete reheat combustors used in traditional approaches. The key questions regarding this approach are whether there is sufficient residence time at high temperature for fuel burnout, and whether increased emissions of NOx and CO result. This project examines the chemical kinetics basis of these questions. In the present task detailed chemical kinetics models were used to evaluate injection reheat combustion. Models used included a Siemens Westinghouse diffusion flame model, the set of CHEMKIN gas-phase kinetics equation solvers, and the GRI 3.0 detailed kinetics data base. These modules are called by a reheat-specific main program, which also provides them with data, including gas path conditions that change with distance through the turbine. Conceptually, injection could occur in either of two ways: (1) direct injection via …
Date: April 30, 2004
Creator: Bachovchin, D. M. & Lippert, T. E.
Object Type: Report
System: The UNT Digital Library
MIDWEST REGIONAL CARBON SEQUESTRATION PARTNERSHIP (MRCSP) (open access)

MIDWEST REGIONAL CARBON SEQUESTRATION PARTNERSHIP (MRCSP)

This is the first semiannual report for Phase I of the Midwest Carbon Sequestration Partnership (MRCSP). The project consists of nine tasks to be conducted over a two year period that started in October 2003. The makeup of the MRCSP and objectives are described. Progress on each of the active Tasks is also described and where possible, for those Tasks at some point of completion, a summary of results is presented.
Date: April 30, 2004
Creator: Ball, David; Bradbury, Judith; Lal, Rattan; Wickstrom, Larry; Gupta, Neeraj; Burns, Robert et al.
Object Type: Report
System: The UNT Digital Library
Abandoned Mine Land Fund Reauthorization: Selected Issues (open access)

Abandoned Mine Land Fund Reauthorization: Selected Issues

This report provides a summary of the structure of the Abandon Mine Land (AML) program, distribution of funds, and discusses major proposals considered in the 108th Congress.
Date: April 30, 2004
Creator: Bamberger, Robert L.
Object Type: Report
System: The UNT Digital Library
Developing State Policies Supportive of Bioenergy Development (open access)

Developing State Policies Supportive of Bioenergy Development

Working within the context of the Southern States Biobased Alliance (SSBA) and with officials in each state, the Southern States Energy Board (SSEB) is identifying bioenergy-related policies and programs within each state to determine their impact on the development, deployment or use of bioenergy. In addition, SSEB will determine which policies have impacted industry's efforts to develop, deploy or use biobased technologies or products. As a result, SSEB will work with the Southern States Biobased Alliance to determine how policy changes might address any negative impacts or enhance positive impacts.
Date: April 30, 2004
Creator: Baskin, Kathryn
Object Type: Report
System: The UNT Digital Library
Bounds on Elastic Constants for Random Polycrystals of Laminates (open access)

Bounds on Elastic Constants for Random Polycrystals of Laminates

A well-known result due to Hill provides an exact expression for the bulk modulus of any multicomponent elastic composite whenever the constituents are isotropic and the shear modulus is uniform throughout. Although no precise analog of Hill's result is available for the opposite case of uniform bulk modulus and varying shear modulus, it is shown here that some similar statements can be made for shear behavior of random polycrystals composed of laminates of isotropic materials. In particular, the Hashin-Shtrikman-type bounds of Peselnick, Meister, and Watt for random polycrystals composed of hexagonal (transversely isotropic) grains are applied to the problem of polycrystals of laminates. An exact product formula relating the Reuss estimate of bulk modulus and an effective shear modulus (of laminated grains composing the system) to products of the eigenvalues for quasi-compressional and quasi-uniaxial shear eigenvectors also plays an important role in the analysis of the overall shear behavior of the random polycrystal. When the bulk modulus is uniform in such a system, the equations are shown to reduce to a simple form that depends prominently on the uniaxial shear eigenvalue - as expected from physical arguments concerning the importance of uniaxial shear in these systems. One application of the …
Date: April 30, 2004
Creator: Berger, E. L.
Object Type: Article
System: The UNT Digital Library
Evelopment of an Environmentally Benign Microbial Inhibitor to Control Internal Pipeline Corrosion (open access)

Evelopment of an Environmentally Benign Microbial Inhibitor to Control Internal Pipeline Corrosion

The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing of pepper extracts resulted in preliminary data indicating that some pepper extracts inhibit the growth of some corrosion-associated microorganisms. This quarter additional tests were performed to more specifically investigate the ability of three pepper extracts to inhibit the growth, and to influence the metal corrosion caused by two microbial species: Desulfovibrio vulgaris, and Comomonas denitrificans. All three pepper extracts rapidly killed Desulfovibrio vulgaris, but did not appear to inhibit Comomonas denitrificans. While corrosion rates were at control levels in experiments with Desulfovibrio vulgaris that received pepper extract, corrosion rates were increased in the presence of Comomonas denitrificans plus pepper extract. Further testing with a wider range of pure bacterial cultures, and more importantly, with mixed bacterial cultures should be performed to determine the potential effectiveness of pepper extracts to inhibit MIC.
Date: April 30, 2004
Creator: Bogan, Bill W.; Sullivan, Wendy R.; Cruz, Kristine M. H.; Lowe, Kristine L. & Kilbane, John J., II
Object Type: Report
System: The UNT Digital Library
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 89, No. 193, Ed. 1 Friday, April 30, 2004 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 89, No. 193, Ed. 1 Friday, April 30, 2004

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: April 30, 2004
Creator: Broaddus, Matthew B.
Object Type: Newspaper
System: The Gateway to Oklahoma History
Perry Daily Journal (Perry, Okla.), Vol. 111, No. 84, Ed. 1 Friday, April 30, 2004 (open access)

Perry Daily Journal (Perry, Okla.), Vol. 111, No. 84, Ed. 1 Friday, April 30, 2004

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: April 30, 2004
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Express-Star (Chickasha, Okla.), Ed. 1 Friday, April 30, 2004 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Friday, April 30, 2004

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: April 30, 2004
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History
The global unified parallel file system (GUPFS) project: FY 2003 activities and results (open access)

The global unified parallel file system (GUPFS) project: FY 2003 activities and results

The Global Unified Parallel File System (GUPFS) project is a multiple-phase project at the National Energy Research Scientific Computing (NERSC) Center whose goal is to provide a scalable, high-performance, high-bandwidth, shared file system for all of the NERSC production computing and support systems. The primary purpose of the GUPFS project is to make the scientific users more productive as they conduct advanced scientific research at NERSC by simplifying the scientists' data management tasks and maximizing storage and data availability. This is to be accomplished through the use of a shared file system providing a unified file namespace, operating on consolidated shared storage that is accessible by all the NERSC production computing and support systems. In order to successfully deploy a scalable high-performance shared file system with consolidated disk storage, three major emerging technologies must be brought together: (1) shared/cluster file systems software, (2) cost-effective, high-performance storage area network (SAN) fabrics, and (3) high-performance storage devices. Although they are evolving rapidly, these emerging technologies individually are not targeted towards the needs of scientific high-performance computing (HPC). The GUPFS project is in the process of assessing these emerging technologies to determine the best combination of solutions for a center-wide shared file system, …
Date: April 30, 2004
Creator: Butler, Gregory F.; P., Baird William; Lee, Rei C.; Tull, Craig E.; Welcome, Michael L. & L., Whitney Cary
Object Type: Report
System: The UNT Digital Library
The Boerne Star (Boerne, Tex.), Vol. 98, No. 35, Ed. 1 Friday, April 30, 2004 (open access)

The Boerne Star (Boerne, Tex.), Vol. 98, No. 35, Ed. 1 Friday, April 30, 2004

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.
Date: April 30, 2004
Creator: Cartwright, Brian & Morgan, Clay
Object Type: Newspaper
System: The Portal to Texas History
Final Report for ''Client Server Software for the National Transport Code Collaboration'' (open access)

Final Report for ''Client Server Software for the National Transport Code Collaboration''

OAK-B135 Tech-X Corporation designed and developed all the networking code tying together the NTCC data server with the data client and the physics server with the data server and physics client. We were also solely responsible for the data and physics clients and the vast majority of the work on the data server. We also performed a number of other tasks.
Date: April 30, 2004
Creator: Cary, John R; Alexander, David; Carlsson, Johan; Luetkemeyer, Kelly & Sizemore, Nathaniel
Object Type: Report
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 82, No. 151, Ed. 1 Friday, April 30, 2004 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 82, No. 151, Ed. 1 Friday, April 30, 2004

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: April 30, 2004
Creator: Cash, Wanda Garner
Object Type: Newspaper
System: The Portal to Texas History
The Message, Volume 39, Number 18, April 2004 (open access)

The Message, Volume 39, Number 18, April 2004

Newsletter of Congregation Beth Yeshurun in Houston, including news and events, upcoming services, member announcements, editorials, and other information of interest to congregants.
Date: April 30, 2004
Creator: Congregation Beth Yeshurun (Houston, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Horizontal Ampoule Growth and Characterization of Mercuric Iodide at Controlled Gas Pressures for X-Ray and Gamma Ray Spectrometers (open access)

Horizontal Ampoule Growth and Characterization of Mercuric Iodide at Controlled Gas Pressures for X-Ray and Gamma Ray Spectrometers

The project developed a new method for producing high quality mercuric iodide crystals of x-ray and gamma spectrometers. Included are characterization of mercuric iodide crystal properties as a function of growth environment and fabrication and demonstration of room-temperature-operated high-resolution mercuric iodide spectrometers.
Date: April 30, 2004
Creator: Corcoran, Douglas S. McGregor Elsa Ariesanti Bridget
Object Type: Report
System: The UNT Digital Library
Analysis of Potential Benefits and Costs of Updating the Commercial Building Energy Code in North Dakota (open access)

Analysis of Potential Benefits and Costs of Updating the Commercial Building Energy Code in North Dakota

The state of North Dakota is considering updating its commercial building energy code. This report evaluates the potential costs and benefits to North Dakota residents from updating and requiring compliance with ASHRAE Standard 90.1-2001. Both qualitative and quantitative benefits and costs are assessed in the analysis. Energy and economic impacts are estimated using the Building Loads Analysis and System Thermodynamics (BLAST simulation combined with a Life-cycle Cost (LCC) approach to assess correspodning economic costs and benefits.
Date: April 30, 2004
Creator: Cort, Katherine A.; Belzer, David B.; Winiarski, David W. & Richman, Eric E.
Object Type: Report
System: The UNT Digital Library
Monitoring of Refractory Wall recession using high temperature impact echo instrumentation (open access)

Monitoring of Refractory Wall recession using high temperature impact echo instrumentation

Regression of refractory linings of furnaces occurs due to a variety of mechanisms. The specific mechanism selected for investigation during this program is the regression of refractories which are in direct contact with a liquid corrodant. Examples include the melting of glass, the production of pig iron and steel, and the melting of aluminum. The rates of regression to a wall thickness which requires reline or extensive reconstruction vary widely, from less than a year to over ten years depending on the specific service environment. This program investigated the feasibility of measuring refractory wall thickness with an impact-echo method while at operating temperature (wall temperatures exceeding 500 C). The impact-echo method uses the impact of a small sphere with the surface of the test object to send a stress wave into the object. In a plate-like structure, the stress wave reflects back to the front surface, reverberating in the structure and causing a periodic surface displacement whose frequency is inversely proportional to the thickness of the test object. Impact-echo testing was chosen because it requires access to only one side of the test object and could be performed during the operation of a refractory structure. Commercially-available impact-echo instrumentation is available …
Date: April 30, 2004
Creator: Dayton, University of
Object Type: Report
System: The UNT Digital Library
Characterization of Uranium in Archived 2H Evaporator Scale (open access)

Characterization of Uranium in Archived 2H Evaporator Scale

This research was conducted to improve our fundamental understanding of the mechanisms of U accumulation with NAS in the evaporators and in other process areas at the SRS that may concentrate U in the presence of silicates, aluminum and NAS. Our study uses information gained from the characterization of solids formed in laboratory tests under similar HLW evaporator conditions to aid our interpretation of characterization data of an actual archived 2H Evaporator scale sample. These basic scientific studies will help support the basis for the continued safe operation of SRS evaporators and this fundamental information will be used to help mitigate U accumulation during evaporator operation.
Date: April 30, 2004
Creator: Duff, M. C.
Object Type: Report
System: The UNT Digital Library
The Alternative Minimum Tax for Individuals (open access)

The Alternative Minimum Tax for Individuals

This report provides a brief overview of the alternative minimum tax (AMT) for individuals, discusses the issues associated with the current system, and describes current legislation to amend the AMT. The report will be updated as legislative action warrants.
Date: April 30, 2004
Creator: Esenwein, Gregg A.
Object Type: Report
System: The UNT Digital Library