We employ a novel, ultrafast terahertz probe to investigatethe dynamical interplay of optically-induced excitons and unboundelectron-hole pairs in GaAs quantum wells. Resonant creation ofheavy-hole excitons induces a new low-energy oscillator linked totransitions between the internal exciton degrees of freedom. The timeresolved terahertz optical conductivity is found to be a probe wellsuited for studies of fundamental processes such as formation, relaxationand ionization of excitons.

Weekly newspaper from Rusk, Texas that includes local, state and national news along with extensive advertising.

Weekly student newspaper from the University of Dallas in Irving, Texas that includes campus news and commentaries along with advertising.

This report provides an overview of the various programs established by Titles III and V of the Higher Education Act (HEA). The report primarily focuses upon the structure of the programs, and includes data on participation and annual funding. It concludes with an analysis of possible issues related to Title III and Title V that may be considered during the HEA reauthorization.

Extended x-ray absorption fine structure spectroscopy (EXAFS) is used to investigate the local atomic environment and vibrational properties of plutonium and gallium atoms in the {alpha}{prime} and {delta} phases of a mixed phase Pu-Ga alloy. EXAFS results measured at low temperature compare the structure of the mixed phase sample with a single-phase {delta}-Pu sample. EXAFS spectral components attributed to both {alpha}{prime}-Pu and {delta}-Pu were observed in the mixed phase sample. Ga K-edge EXAFS spectra indicate local atomic environments similar to the Pu LIII-edge EXAFS results, which suggests that Ga is substitutional for Pu atoms in both the monoclinic {alpha}{prime}-Pu and the fcc {delta}-Pu structures. In {delta}-Pu, we measure a Ga-Pu bond length contraction of 0.11 Angstroms with respect to the Pu-Pu bond length. The corresponding bond-length contraction around Ga in {alpha}{prime}-Pu is only 0.03 Angstroms. Results from temperature-dependent Pu LIII-edge EXAFS measurements are fit to a correlated Debye model, and a large difference in the Pu-Pu bond Debye temperature is observed for the {alpha}{prime} and {delta} phases: {theta}{sub cD}({alpha}{prime})=159{+-}13 K versus {theta}{sub cD}({delta})=120{+-}3 K. The corresponding analysis for the Ga K EXAFS determines a Ga-Pu bond Debye temperature of {theta}{sub cD}({delta})=188{+-}12 K in the {delta}-Pu phase. These results are related …

Weekly newspaper from Wylie, Texas that includes local, state and national news along with advertising.

Semi-weekly newspaper from Clifton, Texas that includes local, state, and national news along with advertising.

Semi-weekly newspaper from Seminole, Texas that includes local, state, and national news along with extensive advertising.

Prior reservoir simulation and laboratory studies have suggested that injecting carbon dioxide into mature natural gas reservoirs for carbon sequestration with enhanced gas recovery (CSEGR) is technically feasible. Reservoir simulations show that the high density of carbon dioxide can be exploited to favor displacement of methane with limited gas mixing by injecting carbon dioxide in low regions of a reservoir while producing from higher regions in the reservoir. Economic sensitivity analysis of a prototypical CSEGR application at a large depleting gas field in California shows that the largest expense will be for carbon dioxide capture, purification, compression, and transport to the field. Other incremental costs for CSEGR include: (1) new or reconditioned wells for carbon dioxide injection, methane production, and monitoring; (2) carbon dioxide distribution within the field; and, (3) separation facilities to handle eventual carbon dioxide contamination of the methane. Economic feasibility is most sensitive to wellhead methane price, carbon dioxide supply costs, and the ratio of carbon dioxide injected to incremental methane produced. Our analysis suggests that CSEGR may be economically feasible at carbon dioxide supply costs of up to $4 to $12/t ($0.20 to $0.63/Mcf). Although this analysis is based on a particular gas field, the approach …

The purpose of this paper is to present lessons learned from fours years' experience conducting Remedial Investigation and Remedial Action activities at the St. Louis Downtown Site (SLDS) under the Formerly Utilized Sites Remedial Action Program (FUSRAP). Many FUSRAP sites are experiencing challenges conducting Remedial Actions within forecasted volume and budget estimates. The St. Louis FUSRAP lessons learned provide insight to options for cost effective remediation at FUSRAP sites. The lessons learned are focused on project planning (budget and schedule), investigation, design, and construction.

A policy-directed framework is developed to support US Department of Energy (DOE) counterterrorism efforts, specifically terrorist intrusion activities that affect of Environmental Management (EM) programs. The framework is called the Security Effectiveness and Resource Allocation Definition Forecasting and Control System (SERAD-FACS). Use of SERAD-FACS allows trade-offs between resources, technologies, risk, and Research and Development (R&D) efforts to mitigate such intrusion attempts. Core to SERAD-FACS is (1) the understanding the perspectives and time horizons of key decisionmakers and organizations, (2) a determination of site vulnerabilities and accessibilities, and (3) quantifying the measures that describe the risk associated with a compromise of EM assets. The innovative utility of SERAD-FACS is illustrated for three integrated waste management and security strategies. EM program risks, time delays, and security for effectiveness are examined to demonstrate the significant cost and schedule impact terrorist activities can have on cleanup efforts in the DOE complex.

The U.S. Department of Energy Environmental Management program (EM) conducts the most extensive environmental remediation effort in the world. The annual EM budgets have exceeded $6,000,000,000 for approximately ten years and EM has assumed responsibility for the cleanup of the largest DOE reservations (i.e., at Hanford, Washington, Aiken, South Carolina, and Idaho Falls, Idaho) as well as the facilities at Rocky Flats, Colorado and in Ohio. Each of these sites has areas of extensive radioactive and chemical contamination, numerous surplus facilities that require decontamination and removal, while some have special nuclear material that requires secure storage. The EM program has been criticized for being ineffective (1) and has been repeatedly reorganized to address perceived shortcomings. The most recent reorganization was announced in 2001 to become effective at the beginning of the 2003 Federal Fiscal Year (i.e., October 2002). It was preceded by a ''top to bottom'' review (TTBR) of the program (2) that identified several deficiencies that were to be corrected as a result of the reorganization. One prominent outcome of the TTBR was the identification of ''risk reduction'' as an organizing principle to prioritize the activities of the new EM program. The new program also sought to accelerate progress …

Numerous buildings throughout the DOE complex are being decommissioned. The decommissioning process typically includes dismantling equipment and utility systems for disposal, decontaminating remaining surfaces to meet regulatory limits, demolishing the building structure, and remediating the surrounding environment to address any historical releases. Typically, a large amount of information and radiation survey data needs to be processed and evaluated. Rapid assessment of project information is required to effectively manage unanticipated conditions that are frequently encountered as building components are dismantled. Parsons has developed a relational database called D&D TRAK to estimate, plan, manage, and track decommissioning projects. D&D TRAK has been successfully used at DOE and other federal facilities to terminate radioactive licenses thus allowing the unrestricted free-release of these buildings to public and private sectors.

This paper explores the trends over 1997-2001 in my baseline simulation analysis of the sufficiency of electric utilities' funds to eventually decommission the nation's nuclear power plants. Further, for 2001, I describe the utilities' funding adequacy results obtained using scenario and sensitivity analyses, respectively. In this paper, I focus more on the wide variability observed in these adequacy measures among utilities than on the results for the ''average'' utility in the nuclear industry. Only individual utilities, not average utilities -- often used by the nuclear industry to represent its funding adequacy -- will decommission their nuclear plants. Industry-wide results tend to mask the varied results for individual utilities. This paper shows that over 1997-2001, the variability of my baseline decommissioning funding adequacy measures (in percentages) for both utility fund balances and current contributions has remained very large, reflected in the sizable ranges and frequency distributions of these percentages. The relevance of this variability for nuclear decommissioning funding adequacy is, of course, focused more on those utilities that show below ideal balances and contribution levels. Looking backward, 42 of 67 utility fund (available) balances, in 2001, were above (and 25 below) their ideal baseline levels; in 1997, 42 of 76 were …

Technology roadmapping can be an effective strategic technology planning tool. This paper describes a process for customizing a generic technology roadmapping process. Starting with a generic process reduces the learning curve and speeds up the roadmap development. Similarly, starting with a generic domain model provides leverage across multiple applications or situations within the domain. A process that combines these two approaches facilitates identifying technology gaps and determining common core technologies that can be reused for multiple applications or situations within the domain. This paper describes both of these processes and how they can be integrated. A core team and a number of technology working groups develop the technology roadmap, which includes critical system requirements and targets, technology areas and metrics for each area, and identifies and evaluates possible technology alternatives to recommend the most appropriate ones to pursue. A generalized waste management model, generated by considering multiple situations or applications in terms of a generic waste management model, provides the domain requirements for the technology roadmapping process. Finally, the paper discusses lessons learns from a number of roadmapping projects.

This paper presents the current results of a study for the optimization of the quality of the wasteform to be produced by vitrification of Hanford High Level Waste (HLW). A simulant of the content of Hanford Tank AZ-101 has been used for the experiments. A first phase of the research focused on the wasteform composition and showed that a high quality and chemical-resistant wasteform can be formed incorporating 60 weight % of dried waste into a borosilicate glass enriched with zinc oxide and boric acid and provided some indication about the heat treatment of the melt. A second phase of the study, still in progress, refines these findings. A detailed crystallinity survey of the waste form after various heat treatments has been performed, culminating in the development of a time-temperature-transformation (TTT) diagram. The results of the first phase of research and preliminary results from the second phase are described.

Improved waste minimization practices at the Department of Energy's (DOE) Idaho National Engineering and Environmental Laboratory (INEEL) are leading to a 15% reduction in the generation of hazardous and radioactive waste. Bechtel, BWXT Idaho, LLC (BBWI), the prime management and operations contractor at the INEEL, applied the Six Sigma improvement process to the INEEL Waste Minimization Program to review existing processes and define opportunities for improvement. Our Six Sigma analysis team: composed of an executive champion, process owner, a black belt and yellow belt, and technical and business team members used this statistical based process approach to analyze work processes and produced ten recommendations for improvement. Recommendations ranged from waste generator financial accountability for newly generated waste to enhanced employee recognition programs for waste minimization efforts. These improvements have now been implemented to reduce waste generation rates and are producing positive results.

Waste managers are increasingly expected to provide good security for the hazardous materials they marshal. Good security requires, among other things, effective tamper and intrusion detection. We have developed and demonstrated a new method for tamper and intrusion detection which we call the ''town crier method''. It avoids many of the problems and vulnerabilities associated with traditional approaches, and has significant advantages for hazardous waste transport. We constructed two rudimentary town crier prototype systems, and tested them for monitoring cargo inside a truck. Preliminary results are encouraging.

Since September 11, waste managers are increasingly expected to provide effective security for their hazardous wastes. Tamper-indicating seals can help. This paper discusses seals, and offers recommendations for how to choose and use them.

This paper describes the successful effort to remove alkali metals, alkali metal residues, and piping and structures from retired non-radioactive test systems on the Hanford Site. These test systems were used between 1965 and 1982 to support the Fast Flux Test Facility and the Liquid Metal Fast Breeder Reactor Program. A considerable volume of sodium and sodium-potassium alloy (NaK) was successfully recycled to the commercial sector; structural material and electrical material such as wiring was also recycled. Innovative techniques were used to safely remove NaK and its residues from a test system that could not be gravity-drained. The work was done safely, with no environmental issues or significant schedule delays.

The legacy project at Lovelace Respiratory Research Institute (LRRI) was an opportunity to work with decades worth of research. LRRI was founded in 1963 to provide inhalation research using radioactive nuclides. Over the next 35 years, scientists at the institute researched the effects of radioactivity on the lungs and the effects of inhaled radiation on the body. There were two outcomes of the research. First, the studies provided valuable information regarding radiation safety and the prevention of the inhalation of radioactive material. Second, the studies created a large amount of legacy waste that is now being cleaned up. Overall, the legacy materials project at LRRI was an interesting challenge. It provided opportunities to the team of LRRI and SEC to engineer solutions to remove and release material. It involved unique ALARA engineering to minimize dose exposure to the project team. And finally, it provided an opportunity to minimize low-level radioactive waste. This paper will expand on the waste management challenges and lessons learned.

This paper provides a summary of investigations done on feasibility of using Ceramicrete technology to stabilize high level salt waste streams typical of Hanford and other sites. We used two non-radioactive simulants that covered the range of properties from low activity to high level liquids and sludges. One represented tank supernate, containing Cr, Pb, and Ag as the major hazardous metals, and Cs as the fission products; the other, a waste sludge, contained Cd, Cr, Ag, Ni, and Ba as the major hazardous contaminants, and Cs, and Tc as the fission products.

The Defense National Stockpile Center (DNSC), a field level activity of the Defense Logistics Agency (DLA) has stewardship of a stockpile of thorium nitrate that has been in storage for decades. The stockpile is made up of approximately 3.2 million kg (7 million lb) of thorium nitrate crystals (hydrate form) stored at two depot locations in the United States. DNSC sought technical assistance from Oak Ridge National Laboratory (ORNL) to define and quantify the management options for the thorium nitrate stockpile. This paper describes methodologies and results comprising the work in Phase 1 and Phase 2. The results allow the DNSC to structure and schedule needed tasks to ensure continued safe long-term storage and/or phased disposal of the stockpile.

Uranium as U(IV) and U(VI) can be selectively recovered from liquids and sludge containing metal precipitates, inorganic salts, sand and silt fines, debris, other contaminants, and slimes, which are very difficult to de-water. Chemical processes such as fuel manufacturing and uranium mining generate enriched and natural uranium-bearing wastes. This patented Framatome ANP (FANP) uranium recovery process reduces uranium losses, significantly offsets waste disposal costs, produces a solid waste that meets mixed-waste disposal requirements, and does not generate metal-contaminated liquids. At the head end of the process is a floating dredge that retrieves liquids, sludge, and slimes in the form of a slurry directly from the floor of a lined surface impoundment (lagoon). The slurry is transferred to and mixed in a feed tank with a turbine mixer and re-circulated to further break down the particles and enhance dissolution of uranium. This process uses direct steam injection and sodium hypochlorite addition to oxidize and dissolves any U(IV). Cellulose is added as a non-reactive filter aid to help filter slimes by giving body to the slurry. The slurry is pumped into a large recessed-chamber filter press then de-watered by a pressure cycle-controlled double-diaphragm pump. U(VI) captured in the filtrate from this process …