A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of tailings ash content. Then, based on an on-line estimate of incremental ash, the pulp level is adjusted using a model-based control algorithm to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the eleventh quarter of this project, Task 7 (Operation and Testing) was nearly completed through the efforts of J.A. Herbst and Associates, Virginia Tech, and Pittston Coal Company. As a result of this work, a model-based control system has now been installed which can predict incremental ash based on tailings ash content and general plant data, and adjust pulp level accordingly to maintain a target incremental ash. The system has gone through a shake-down period, training has been carried out for plant operators, and the bulk of the control logic testing has been completed with the results of these tests awaiting analysis under Task 8 (System Evaluation). The flotation model has been shown to predict incremental ash quite successfully, implying that this approach …

Arrays of unheated chemically sensitive resistors (chemiresistors) can serve as extremely small, low-power-consumption sensors with simple read-out electronics. We report here results on carbon-loaded polymer composites, as well as polymeric ionic conductors, as chemiresistor sensors. We use the volubility parameter concept to understand and categorize the chemiresistor responses and, in particular, we compare chemiresistors fabricated from polyisobutylene (PIB) to results from PIB-coated acoustic wave sensors. One goal is to examine the possibility that a small number of diverse chemiresistors can sense all possible solvents-the "Universal Solvent Sensor Array". keywords: chemiresistor, volubility parameter, chemical sensor

Limited availability of fresh water in arid and semi-arid regions of the world requires prudent management strategies from accurate, science-based assessments. These assessments demand a thorough understanding of the hydrologic cycle over long time periods within the individual water-sheds that comprise large river basins. Measurement and simulation of the hydrologic cycle is a tremendous challenge, involving a coupling between global to regional-scale atmospheric precipitation processes with regional to local-scale land surface and subsurface water transport. Los Alamos National Laboratory is developing a detailed modeling system of the hydrologic cycle and applying this tool at high resolution to assess the water balance within the upper Rio Grande river basin. The Rio Grande is a prime example of a river system in a semiarid environment, with a high demand from agricultural, industrial, recreational, and municipal interests for its water supply. Within this river basin, groundwater supplies often augment surface water. With increasing growth projected throughout the river basin, however, these multiple water users have the potential to significantly deplete groundwater resources, thereby increasing the dependence on surface water resources.

The effects of nitrided SiO{sub 2}/Si(100) interfaces upon cycling endurance in silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory transistors are investigated. Analysis of MOSFET sub-threshold characteristics indicate cycling degradation to be a manifestation of interface state (D{sub it}) generation at the tunnel oxide/silicon interface. After 10{sup 6} write/erase cycles, SONOS film stacks prepared with nitrided tunnel oxides exhibit enhanced cycling endurance with {Delta}D{sub it}=3x10{sup 12} V{sup -1}cm{sup -2}, compared to {Delta}D{sub it}=2x10{sup 13} V{sup -l}cm{sup -2} for non-nitrided tunnel oxides. Additionally, if the capping oxide is formed by steam oxidation, rather than by deposition, SONOS stacks prepared with non-nitrided tunnel oxides exhibit endurance characteristics similar to stacks with nitrided tunnel oxides. From this observation it is concluded that latent nitridation of the tunnel oxidehilicon interface occurs during steam oxide cap formation.

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the: (1) Department of Labor's response to the House Appropriations Committee's directive that it verify a random sample of employers' wage data submissions and select a sample of submissions for on-site data verification; and (2) likely effect of these efforts on the accuracy and timeliness of Davis-Bacon Act wage determinations."

The Earth is periodically hit by near Earth objects (NEOs) ranging in size from dust to mountains. The small ones are a useful source of information, but those larger than about 1 km can cause global damage. The requirements for the deflection of NEOs with significant material strength are known reasonably well; however, the strength of large NEOs is not known, so those requirements may not apply. Meteor impacts on the Earth`s atmosphere give some information on strength as a function of object size and composition. This information is used here to show that large, weak objects could also be deflected efficiently, if addressed properly.

This report briefly discusses committee markups in the House of Representatives. The essential purpose of a committee markup is to determine whether a measure pending before a committee should be altered, or amended, in any substantive way. Of course, committees do not actually amend measures; instead a committee votes on which amendments it wishes to recommend to the House.

Markups provide Members on a committee an opportunity to change parts of a bill prior to its consideration by the full House. A number of administrative, procedural, and substantive steps must be undertaken in preparation for a markup, and other steps could or should be undertaken. Generally, the markup should be strategically planned to minimize controversy, provide Members with political dividends, and position the committee for future action. This report is intended as a guide for various tasks that could be accomplished by committee staff in order to prepare a smooth committee markup.

At the end of the amendment process, the chair normally entertains a motion to report a measure favorably to the House. This report addresses the procedural options committees have regarding the form of reporting, such as what happens to amendments adopted in markup, as well as other considerations at the time of reporting.

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed states' and local agencies' efforts to improve the timeliness of judicial decisions concerning the permanent placement of foster children, focusing on: (1) the key problems in the juvenile dependency court system; and (2) state and local responses to these problems."

''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

The organization and assembly of molecules in cellular membranes is orchestrated through the recognition and binding of specific chemical signals. A simplified version of the cellular membrane system has been developed using a synthetically prepared membrane receptor incorporated into a biologically derived lipid bilayer. Through an interplay of electrostatic and van der Wards interactions, aggregation or dispersion of molecular components could be executed on command using a specific chemical signal. A pyrene fluorophore was used as an optical probe to monitor the aggregational state of the membrane receptors in the bilayer matrix. The pyrene excimer emission to monomer emission (E/M) intensity ratio gave a relative assessment of the local concentration of receptors in the membrane. Bilayers were prepared with receptors selective for the divalent metal ions of copper, mercury, and lead. Addition of the metal ions produced a rapid dispersion of aggregated receptor components at nano- to micro-molar concentrations. The process was reversible by sequestering the metal ions with EDTA. Receptors for proteins and polyhistidine were also prepared and incorporated into phosphatidylcholine lipid bilayers. In this case, the guest molecules bound to the membrane through multiple points of interaction causing aggregation of initially dispersed receptor molecules. The rapid, selective, and …

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Point defects in the binary C15 NbCrQ and NbCoz, and C 14 NbFe2 systems on both sides of stoichiometry were studied by both bulk density and X-ray Iattiee parameter measurements. It was found that the vacancy concentrations in these systems after quenching from 1000"C are essentially zero. The constitutional defects on both sides of stoichiometry for these systems were found to be of the anti-site type in comparison with the model predictions. Thermal vacancies exhibiting a maximum at the stoichiometric composition were obtained in NbCr2 Laves phase alloys after quenching from 1400"C. However, there are essentially no thermal vacancies in NbFe2 alloys after quenching from 1300oC. Anti-site hardening was found on both sides of stoichiometry for all the tie Laves phase systems studied, while the thermal vacancies in NbCr2 alloys quenched from 1400'C were found to soften the Laves phase. The anti-site hardening of the Laves phases is similar to that of the B2 compounds and the thermal vacancy softening is unique to the Laves phase. Neither the anti-site defects nor the thermal vacancies affect the fracture toughness of the Laves phases significantly.

We have developed instrumentation to enable the combination of surface acoustic wave (SAW) sensor measurements with direct, in-situ molecular spectroscopic measurements to understand the response of the SAW sensors with respect to the interfacial chemistry of surface-confined sensing films interacting with gas-phase analytes. Specifically, the instrumentation and software was developed to perform in-situ Fourier-transform infrared external-reflectance spectroscopy (FTIR-ERS) on operating SAW devices during dosing of their chemically modified surfaces with analytes. By probing the surface with IR spectroscopy during gas exposure, it is possible to understand in unprecedented detail the interaction processes between the sorptive SAW coatings and the gaseous analyte molecules. In this report, we provide details of this measurement system, and also demonstrate the utility of these combined measurements by characterizing the SAW and FTIR-ERS responses of organic thin-film sensor coatings interacting with gas-phase analytes.

Ceramic materials are used extensively in non-nuclear components in the weapons stockpile including neutron tubes, stronglinks, weaklinks, batteries, and current/voltage stacks. Ceramics also perform critical functions in electronics, passively as insulators and actively as resistors and capacitors, Glass and ceramic seals also provide hermetic electrical feedthrus in connectors for many weapons components.

Growth kinetics, mechanisms, and material quality in GaN epitaxial lateral over-growth (ELO) were examined using a single mask of systematically varied patterns. A 2-D gas phase reaction/diffusion model describes how transport of the Ga precursor to the growth surface enhances the lateral rate in the early stages of growth. In agreement with SEM studies of truncated growth runs, the model also predicts the dramatic decrease in the lateral rate that occurs as GaN over-growth reduces the exposed area of the mask. At the point of convergence, a step-flow coalescence mechanism is observed to fill in the area between lateral growth-fronts. This alternative growth mode in which a secondary growth of GaN is nucleated along a single convergence line, may be responsible for producing smooth films observed to have uniform cathodoluminescence (CL) when using 1{micro}m nucleation zones. Although emission is comprised of both UV ({approximately}365nm) and yellow ({approximately}550nm) components, the spectra suggest these films have reduced concentrations of threading dislocations normally associated with non-radiative recombination centers and defects known to accompany growth-front convergence lines.

An annual appropriations act generally consists of two parts – paragraphs providing funding, and general provisions focusing on non-funding as well as funding issues. Discussed on this brief fact sheet are what is found in general provisions of appropriations bills.

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the Coast Guard's budgets for fiscal years 1999 and 2000, focusing on the: (1) Coast Guard's progress in justifying the Deepwater Replacement Project and addressing GAO's concerns about its affordability; (2) Coast Guard's plans for spending its fiscal year (FY) 1999 emergency funds; and (3) budget strategies the agency may have to consider in the future to address continuing budget constraints."

A chapter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Customs Service's software development maturity and improvement activities, focusing on: (1) the maturity of Customs' software development processes; and (2) whether Customs has an effective software process improvement program."

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed: (1) the level of carryover balances held by the Department of Energy's (DOE) Energy Conservation Program and the trend of these balances since fiscal year (FY) 1997; and (2) its methodology for determining the amount of carryover balances that may be available to reduce DOE's budget requests and how it differs from the methodology used by DOE."

An annual appropriations act is generally made up of separate paragraphs, each of which provides funding for specific agencies and programs. Generally, each paragraph corresponds to a unique account and provides appropriations for multiple projects and purposes as a single lump sum. Earmarks and limitations are two devices regularly used in annual appropriations acts to restrict, or more precisely direct, the availability of funds for specific projects or purposes of an account. Sometimes an earmark or a limitation may generate more interest or controversy than the total appropriation.

This environmental assessment was prepared to assess potential environmental impacts associated with the proposed action to widen and operate unused Trench 36 in the 218-E-12B Low-Level Burial Ground for disposal of low-level waste. Information contained herein will be used by the Manager, U.S. Department of Energy, Richland Operations Office, to determine if the Proposed Action is a major federal action significantly affecting the quality of the human environment. If the Proposed Action is determined to be major and significant, an environmental impact statement will be prepared. If the Proposed Action is determined not to be major and significant, a Finding of No Significant Impact will be issued and the action may proceed. Criteria used to evaluate significance can be found in Title 40, Code of Federal Regulations 1508.27. This environmental assessment was prepared in compliance with the ''National Environmental Policy Act of1969'', as amended, the Council on Environmental Quality Regulations for Implementing the Procedural Provisions of ''National Environmental Policy Act'' (Title 40, Code of Federal Regulations 1500-1508), and the U.S. Department of Energy Implementing Procedures for ''National Environmental Polio Act'' (Title 10, Code of Federal Regulations 1021). The following is a description of each section of this environmental assessment. (1) …

Other written product issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the Federal Communications Commission (FCC) new rule on direct broadcast satellite public interest obligations. GAO noted that: (1) the rule would impose requirements on direct broadcast satellite service (DBS) providers to comply with the political broadcast rules of the Communications Act of 1934, as amended, and mandates that the DBS providers reserve between 4 percent and 7 percent of their channel capacity exclusively for noncommercial programming of an educational or informational nature; and (2) FCC complied with applicable requirements in promulgating the rule."