Environmentalmanagement Science Program Project Number 87016 Co-Precipitation of Tracemetals Ingroundwater and Vadose Zone Calcite: In Situ Containment and Stabilization of Strontium-90 Andother Divalent Metals and Radionuclides at Aridwestern Doe Sites (open access)

Environmentalmanagement Science Program Project Number 87016 Co-Precipitation of Tracemetals Ingroundwater and Vadose Zone Calcite: In Situ Containment and Stabilization of Strontium-90 Andother Divalent Metals and Radionuclides at Aridwestern Doe Sites

Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. In situ containment and stabilization of these contaminants in vadose zones or groundwater is a cost-effective treatment strategy. Our facilitated approach relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal coprecipitation) by increasing groundwater pH and alkalinity (Fujita et al., 2000; Warren et al., 2001). Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation processes are irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from groundwater. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution (Zachara et al., 1991), solid solution properties of the trace metal in calcite (Tesoriero and Pankow, 1996), and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning, and how …
Date: June 15, 2004
Creator: Ferris, F. Grant; Fujita, Yoshiko; Smith, Robert W.; Cosgrove, Donna M. & Colwell, F. S.
Object Type: Report
System: The UNT Digital Library
Screening Analysis of Criticality Features, Events, and Processes for License Application (open access)

Screening Analysis of Criticality Features, Events, and Processes for License Application

None
Date: October 15, 2004
Creator: McClure, J.A.
Object Type: Report
System: The UNT Digital Library
Wetland Plant Guide for Assessing Habitat Impacts of Real-Time Salinity Management (open access)

Wetland Plant Guide for Assessing Habitat Impacts of Real-Time Salinity Management

This wetland plant guide was developed to aid moist soil plant identification and to assist in the mapping of waterfowl and shorebird habitat in the Grassland Water District and surrounding wetland areas. The motivation for this habitat mapping project was a concern that real-time salinity management of wetland drainage might have long-term consequences for wildfowl habitat health--changes in wetland drawdown schedules might, over the long term, lead to increased soil salinity and other conditions unfavorable to propagation of the most desirable moist soil plants. Hence, the implementation of a program to monitor annual changes in the most common moist soil plants might serve as an index of habitat health and sustainability. Our review of the current scientific and popular literature failed to identify a good, comprehensive field guide that could be used to calibrate and verify high resolution remote sensing imagery, that we had started to use to develop maps of wetland moist soil plants in the Grassland Water District. Since completing the guide it has been used to conduct ground truthing field surveys using the California Native Plant Society methodology in 2004. Results of this survey and a previous wetland plant survey in 2003 are published in a companion …
Date: October 15, 2004
Creator: Quinn, Nigel W.T. & Feldmann, Sara A.
Object Type: Report
System: The UNT Digital Library
Wyoming DOE EPSCoR (open access)

Wyoming DOE EPSCoR

All of the research and human resource development projects were systemic in nature with real potential for becoming self sustaining. They concentrated on building permanent structure, such as faculty expertise, research equipment, the SEM Minority Center, and the School of Environment and Natural Resources. It was the intent of the DOE/EPSCoR project to permanently change the way Wyoming does business in energy-related research, human development for science and engineering careers, and in relationships between Wyoming industry, State Government and UW. While there is still much to be done, the DOE/EPSCoR implementation award has been successful in accomplishing that change and enhancing UW's competitiveness associated with coal utilization, electrical energy efficiency, and environmental remediation.
Date: January 15, 2004
Creator: Gern, W.A.
Object Type: Report
System: The UNT Digital Library
Polarized x-rays as a probe of spin polarization and interface and confinement effects: Theoretical approach (open access)

Polarized x-rays as a probe of spin polarization and interface and confinement effects: Theoretical approach

Progress report for grant from the Division of Materials Sciences and Engineering Office of Basic Energy Sciences (Program manager Dale Koelling)
Date: March 15, 2004
Creator: Veenendaal, Michel van
Object Type: Report
System: The UNT Digital Library
Molecular Biology for the Environment: an EC-US hands-on Course in Environmental Biotechnology (open access)

Molecular Biology for the Environment: an EC-US hands-on Course in Environmental Biotechnology

One of the central goals of this activity is to bring together young scientists (at the late Ph.D. or early postdoctoral stages of their careers) in a forum that should result in future collaborations. The course is designed to give scientists hands-on experience in modern, up-to-date biotechnological methods at the interface between molecular biology and environmental biotechnology for the analysis of microorganisms and their activities with regard to the remediation of pollutants in the environment.
Date: February 15, 2004
Creator: Lorenzo, Victor de; Ramos, Juan Luis; Kukor, Jerome & Zylstra, Gerben J.
Object Type: Article
System: The UNT Digital Library
Isotopically controlled semiconductors (open access)

Isotopically controlled semiconductors

A review of recent research involving isotopically controlled semiconductors is presented. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, can be considered the most important one for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples. Manuel Cardona, the longtime editor-in-chief of Solid State Communications has been and continues to be one of the major contributors to this field of solid state physics and it is a great pleasure to dedicate this review to him.
Date: November 15, 2004
Creator: Haller, E. E.
Object Type: Article
System: The UNT Digital Library
Sum frequency generation (SFQ) vibrational spectroscopy studies of combustion reactions on platinum single crystal surfaces (open access)

Sum frequency generation (SFQ) vibrational spectroscopy studies of combustion reactions on platinum single crystal surfaces

We have studied the dissociation of CO catalyzed by platinum single crystals. At 40 torr of CO, the Pt(111) crystal dissociates CO at 673 K. Under the same conditions, Pt(100) dissociates CO at 500 K, and Pt(557) dissociates CO at 548 K. Hence, the CO dissociation reaction is a structure sensitive reaction. SFG was used to monitor the CO top site resonance as the platinum crystals were heated to the dissociation temperature when exposed to 40 torr of CO. In all three systems, the CO resonance shifts to lower frequency as the platinum crystal is heated. However, the frequency of the CO resonance at the dissociation frequency is lower on the (100) and (111) crystal faces than on the Pt(557) crystal. We believe that the (111) and (100) crystal faces must undergo roughening to expose step or kink sites in order to facilitate the dissociation reaction. This is supported by UHV studies of CO dissociation catalyzed by platinum crystals. These studies observe dissociation only when step or kink sites are present. Since the Pt(111) surface is very stable, it needs to be heated to 673 K to produce the low coordination number sites needed for CO dissociation. Since the Pt(100) …
Date: January 15, 2004
Creator: Gaughan, Jessica S.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
DWPF Air Lift Pump Life Cycle Evaluation (open access)

DWPF Air Lift Pump Life Cycle Evaluation

The Defense Waste Processing Facility (DWPF) air lift pump was successfully tested at Clemson for 72 days of operation. It provided sufficient flow to pump molten glass without excessive foaming. Slurry feeding also did not reveal any problems with cold cap stability. Metallurgically the Inconel 690 (690) portions of the pump were in excellent condition with no visual evidence of degradation even in high flow regions, i.e., air/melt interface and glass discharge regions. Spinel deposits, which completely covered the air passage on one side, were found at the inlet of each platinum/rhodium (Pt/Rh) nozzle. Although the deposits were extensive, they were porous and did not have an adverse effect on the operation of the pump. The technique used to secure the platinum/rhodium nozzles to the 690 housing appeared to be adequate with only minor oxidation of the 690 threads and glass in-leakage. Galvanic attack was observed where the nozzle formed a seal with the 690. Significant pitting of the 690 was observed around the entire seal. Intergranular cracking of the Pt/Rh alloy was extensive but the cause could not be determined. Testing would be required to evaluate the degradation. Data from the performance test and the metallurgical evaluation are being …
Date: March 15, 2004
Creator: IMRICH, KENNETH
Object Type: Report
System: The UNT Digital Library
The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (Japanese translation) (open access)

The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (Japanese translation)

The August 2003 blackout of the northeastern U.S. and CANADA caused great economic losses and inconvenience to New York City and other affected areas. The blackout was a warning to the rest of the world that the ability of conventional power systems to meet growing electricity demand is questionable. Failure of large power systems can lead to serious emergencies. Introduction of on-site generation, renewable energy such as solar and wind power and the effective utilization of exhaust heat is needed, to meet the growing energy demands of the residential and commercial sectors. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems. This work demonstrates a method for choosing and designing economically optimal DER systems. An additional purpose of this research is to establish a database of energy tariffs, DER technology cost and performance characteristics, and building energy consumption for Japan. This research builds on prior DER studies at the Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) and with their associates in the Consortium for Electric Reliability Technology Solutions (CERTS) and operation, including the development of the microgrid concept, and the DER selection optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM …
Date: October 15, 2004
Creator: Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun & Nishida, Masaru
Object Type: Report
System: The UNT Digital Library
Elemental Composition of a Composite of Samples HTF-E-03-162 to 164 From Tank 51H to Evaluate Acceptability of the Sludge for Transfer to Tank 40H and Processing in the DWPF (open access)

Elemental Composition of a Composite of Samples HTF-E-03-162 to 164 From Tank 51H to Evaluate Acceptability of the Sludge for Transfer to Tank 40H and Processing in the DWPF

Three dip samples of suspended sludge slurry were obtained from Tank 51H and sent to the Savannah River Technology Center for analysis. The composite of these samples is intended as a confirmatory sample to evaluate the acceptability of the Tank 51H sludge slurry for transfer to Tank 40H and for eventual processing in the Defense Waste Processing Facility. This report presents results of analyses requested by the Defense Waste Processing Facility for this evaluation. These analyses included the measurement of the concentrations of twenty two elements in the sludge slurry and the determination of the weight percent calcined solids of the slurry.
Date: April 15, 2004
Creator: Bibler, N. E.
Object Type: Report
System: The UNT Digital Library
Press and Dryer Roll Surgaces and Web Transfer Systems for Ultra High Paper Maching Speeds (open access)

Press and Dryer Roll Surgaces and Web Transfer Systems for Ultra High Paper Maching Speeds

The objective of the project was to provide fundamental knowledge and diagnostic tools needed to design new technologies that will allow ultra high speed web transfer from press rolls and dryer cylinders.
Date: March 15, 2004
Creator: Patterson, T. F.
Object Type: Report
System: The UNT Digital Library
The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (English Version) (open access)

The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (English Version)

The August 2003 blackout of the northeastern U.S. and CANADA caused great economic losses and inconvenience to New York City and other affected areas. The blackout was a warning to the rest of the world that the ability of conventional power systems to meet growing electricity demand is questionable. Failure of large power systems can lead to serious emergencies. Introduction of on-site generation, renewable energy such as solar and wind power and the effective utilization of exhaust heat is needed, to meet the growing energy demands of the residential and commercial sectors. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems. This work demonstrates a method for choosing and designing economically optimal DER systems. An additional purpose of this research is to establish a database of energy tariffs, DER technology cost and performance characteristics, and building energy consumption for Japan. This research builds on prior DER studies at the Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) and with their associates in the Consortium for Electric Reliability Technology Solutions (CERTS) and operation, including the development of the microgrid concept, and the DER selection optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM …
Date: October 15, 2004
Creator: Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun & Nishida, Masaru
Object Type: Report
System: The UNT Digital Library
Deposition Diagnostics for Next-step Devices (open access)

Deposition Diagnostics for Next-step Devices

The scale-up of deposition in next-step devices such as ITER will pose new diagnostic challenges. Codeposition of hydrogen with carbon needs to be characterized and understood in the initial hydrogen phase in order to mitigate tritium retention and qualify carbon plasma facing components for DT operations. Plasma facing diagnostic mirrors will experience deposition that is expected to rapidly degrade their reflectivity, posing a new challenge to diagnostic design. Some eroded particles will collect as dust on interior surfaces and the quantity of dust will be strictly regulated for safety reasons - however diagnostics of in-vessel dust are lacking. We report results from two diagnostics that relate to these issues. Measurements of deposition on NSTX with 4 Hz time resolution have been made using a quartz microbalance in a configuration that mimics that of a typical diagnostic mirror. Often deposition was observed immediately following the discharge suggesting that diagnostic shutters should be closed as soon as possible after the time period of interest. Material loss was observed following a few discharges. A novel diagnostic to detect surface particles on remote surfaces was commissioned on NSTX.
Date: June 15, 2004
Creator: Skinner, C. H.; Roquemore, A. L.; NSTX team; Bader, A. & Wampler, W. R.
Object Type: Report
System: The UNT Digital Library
Exotic physics: search for doubly-charged higgs bosons decaying to dileptons in p anti-p collisions at s**(1/2) = 1.96 tev (open access)

Exotic physics: search for doubly-charged higgs bosons decaying to dileptons in p anti-p collisions at s**(1/2) = 1.96 tev

The authors present the results of a search for doubly-charged Higgs bosons (H{sup {+-}}{sup {+-}}) decaying to dileptons (ll') using {approx} 240 pb{sup -1} of p{bar p} collision data collected by the CDF II experiment at the Fermilab Tevatron. In the search region, given by same-sign ll' mass m{sub ll'} > 80 GeV/c{sup 2} (100 GeV/c{sup 2} for ee channel), they observe no evidence for H{sup {+-}}{sup {+-}} production. They set limits on {sigma}(p{bar p} {yields} H{sup ++}H{sup --} {yields} l{sup +}l'{sup +}l{sup -}l'{sup -}) as a function of the mass of the H{sup {+-}}{sup {+-}} and the chirality of its couplings. Assuming exclusive same-sign dilepton decays, they derive lower mass limits on H{sub L}{sup {+-}}{sup {+-}} of 133 GeV/c{sup 2}, 136 GeV/c{sup 2}, and 115 GeV/c{sup 2} in the ee, {mu}{mu}, and e{mu} channels, respectively, and a lower mass limit of 113 GeV/c{sup 2} on H{sub R}{sup {+-}}{sup {+-}} in the {mu}{mu} channel, all at the 95% confidence level.
Date: November 15, 2004
Creator: Acosta, D.
Object Type: Report
System: The UNT Digital Library
Computational Design of Metal Ion Sequestering Agents (open access)

Computational Design of Metal Ion Sequestering Agents

Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that target specific radionuclides. Members of the Group 1A and 2A cations (e.g., Cs, Sr, Ra) and the f-block metals (actinides and lanthanides) are of primary concern to DOE. Although there has been some success in identifying ligand architectures that exhibit a degree of metal ion recognition, the ability to control binding affinity and selectivity remains a significant challenge. The traditional approach for discovering such ligands has involved lengthy programs of organic synthesis and testing that, in the absence of reliable methods for screening compounds before synthesis, have resulted in much wasted research effort. This project seeks to enhance and strengthen the traditional approach through computer-aided design of new and improved host molecules. Accurate electronic structure calculations are coupled with experimental data to provide fundamental information about ligand structure and the nature of metal-donor group interactions (design criteria). This fundamental information then is used in a molecular mechanics model (MM) that helps us rapidly screen proposed ligand architectures and select the best members …
Date: June 15, 2004
Creator: Hay, Benjamin P. & Rapko, Brian M.
Object Type: Report
System: The UNT Digital Library
Small Angle X-Ray Scattering Detector (open access)

Small Angle X-Ray Scattering Detector

A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.
Date: June 15, 2004
Creator: Hessler, Jan P.
Object Type: Text
System: The UNT Digital Library
Identification of Non-Pertechnetate Species in Hanford Tank Waste, Their Synthesis, Characterization, and Fundamental Chemistry (open access)

Identification of Non-Pertechnetate Species in Hanford Tank Waste, Their Synthesis, Characterization, and Fundamental Chemistry

Technetium, as pertechnetate (TcO4 -), is a mobile species in the environment. This characteristic, along with its long half-life, (99Tc, t1/2 = 213,000 a) makes technetium a major contributor to the long-term hazard associated with low level waste (LLW) disposal. Technetium partitioning from the nuclear waste at DOE sites may be required so that the LLW forms meet DOE performance assessment criteria. Technetium separations assume that technetium exists as TcO4 - in the waste. However, years of thermal, chemical, and radiolytic digestion in the presence of organic material, has transformed much of the TcO4 - into unidentified, stable, reduced, technetium complexes. To successfully partition technetium from tank wastes, it will be necessary to either remove these technetium species with a new process, or reoxidize them to TcO4 - so that conventional pertechnetate separation schemes will be successful.
Date: June 15, 2004
Creator: Schroeder, Norman C.; Ashley, Kenneth R. & Olivares, Jose A.
Object Type: Report
System: The UNT Digital Library
Rayleigh-Taylor and Richtmyer-Meshkov Instabilities and Mixing in Stratified Cylindrical Shells (open access)

Rayleigh-Taylor and Richtmyer-Meshkov Instabilities and Mixing in Stratified Cylindrical Shells

We study the linear stability of an arbitrary number N of cylindrical concentric shells undergoing a radial implosion or explosion.We derive the evolution equation for the perturbation {eta}{sub i} at interface i; it is coupled to the two adjacent interfaces via {eta}{sub i{+-}1}. For N=2, where there is only one interface, we verify Bell's conjecture as to the form of the evolution equation for arbitrary {rho}{sub 1} and {rho}{sub 2}, the fluid densities on either side of the interface. We obtain several analytic solutions for the N=2 and 3 cases. We discuss freeze-out, a phenomenon that can occur in all three geometries (planar, cylindrical, or spherical), and ''critical modes'' that are stable for any implosion or explosion history and occur only in cylindrical or spherical geometries. We present numerical simulations of possible gelatin-ring experiments illustrating perturbation feedthrough from one interface to another. We also develop a simple model for the evolution of turbulent mix in cylindrical geometry and define a geometrical factor G as the ratio h{sub cylindrical}/h{sub planar} between cylindrical and planar mixing layers. We find that G is a decreasing function of R/R{sub o}, implying that in our model h{sub cylindrical} evolves faster (slower) than h{sub planar} during …
Date: April 15, 2004
Creator: Mikaelian, K O
Object Type: Article
System: The UNT Digital Library
SECA Annual Workshop and Core Technology Peer Review (open access)

SECA Annual Workshop and Core Technology Peer Review

Proceedings of the SECA Annual Workshop and Core Technology Meeting.
Date: July 15, 2004
Creator: NETL & PNNL
Object Type: Article
System: The UNT Digital Library
Cathepsin L is required for endothelial progenitor cell-induced neovascularization (open access)

Cathepsin L is required for endothelial progenitor cell-induced neovascularization

Infusion of endothelial progenitor cells (EPCs), but not of mature endothelial cells (ECs), promotes neovascularization after ischemia. We performed a gene expression profiling of EPCs and ECs to identify genes, which might be important for the neovascularization capacity of EPCs. Intriguingly, the protease cathepsin L (CathL) was highly expressed in EPCs as opposed to ECs and is essential for matrix degradation and invasion by EPCs in vitro. CathL deficient mice showed impaired functional recovery after hind limb ischemia supporting the concept for an important role of CathL in postnatal neovascularization. Infused CathL deficient progenitor cells failed to home to sites of ischemia and to augment neovascularization. In contrast, over expression of CathL in mature ECs significantly enhanced their invasive activity and induced their neovascularization capacity in vivo. Taken together, CathL plays a crucial role for the integration of circulating EPCs into the ischemic tissue and is required for neovascularization mediated by EPCs.
Date: January 15, 2004
Creator: Urbich, Carmen; Heeschen, Christopher; Aicher, Alexandra; Sasaki, Ken-ichiro; Bruhl, Thomas; Hofmann, Wolf K. et al.
Object Type: Article
System: The UNT Digital Library
COMPARATIVE EVALUATION OF AMBIENT FINE PARTICULATE MATTER (PM2.5) DATA OBTAINED FROM URBAN AND RURAL MONITORING SITES ALONG THE UPPER OHIO RIVER VALLEY (open access)

COMPARATIVE EVALUATION OF AMBIENT FINE PARTICULATE MATTER (PM2.5) DATA OBTAINED FROM URBAN AND RURAL MONITORING SITES ALONG THE UPPER OHIO RIVER VALLEY

Advanced Technology Systems, Inc. (ATS), with Desert Research Institute (DRI) and Ohio University as subcontractors, was contracted by the NETL in September 1998 to manage the Upper Ohio River Valley Project (UORVP), which included the establishment and operation of four ambient air monitoring sites located in the Upper Ohio River Valley (UORV). Two urban and two rural monitoring sites were included in the UORVP. The four sites selected for the UOVRP were collocated at existing local and/or state air quality monitoring stations. The goal of the UORVP was to characterize the nature and composition of PM{sub 2.5} and its precursor gases. In the process, the objectives of the UORVP were to examine the ambient air concentrations of PM{sub 2.5} as compared with the promulgated PM{sub 2.5} standards, the geographical, seasonal and temporal variations of ambient air concentrations of PM{sub 2.5}, the primary chemical constituents of PM{sub 2.5}, and the correlations between ambient air concentrations of PM{sub 2.5} and its precursor gases, other gaseous pollutants and meteorological parameters. A variety of meteorological and pollutant measurement devices, including several different PM{sub 2.5} samplers that provided either real-time or integrated concentration data, were deployed at the monitoring sites. The frequency of integrated sampling …
Date: April 15, 2004
Creator: Khosah, Robinson P.; Shimshock, John P. & Penland, Jerry L.
Object Type: Report
System: The UNT Digital Library
HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS (open access)

HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS

The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80 C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for …
Date: November 15, 2004
Creator: Kabadi, Vinayak N.
Object Type: Report
System: The UNT Digital Library
Energy Consumption of Die Casting Operations (open access)

Energy Consumption of Die Casting Operations

Molten metal processing is inherently energy intensive and roughly 25% of the cost of die-cast products can be traced to some form of energy consumption [1]. The obvious major energy requirements are for melting and holding molten alloy in preparation for casting. The proper selection and maintenance of melting and holding equipment are clearly important factors in minimizing energy consumption in die-casting operations [2]. In addition to energy consumption, furnace selection also influences metal loss due to oxidation, metal quality, and maintenance requirements. Other important factors influencing energy consumption in a die-casting facility include geographic location, alloy(s) cast, starting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting machine, related equipment (robots, trim presses), and downstream processing (machining, plating, assembly, etc.). Each of these factors also may influence the casting quality and productivity of a die-casting enterprise. In a die-casting enterprise, decisions regarding these issues are made frequently and …
Date: March 15, 2004
Creator: Brevick, Jerald; Mount-Campbell, clark & Mobley, Carroll
Object Type: Report
System: The UNT Digital Library