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CEBAF is a 4 GeV, 200 {micro}A five-pass recirculating superconducting electron accelerator that has been operating for nuclear physics research at full energy since November 95. The beam current has been increased to over 180 {micro}A at 4 GeV with the maximum current in the linac over 900 {micro}A. The superconducting cavities operate in a regime where the beam-induced voltage is comparable to the accelerating gradient. The operational limits and the issues required to maintain stable operation of the 1,497 MHz superconducting cavities will be discussed, together with the implications for the other accelerator systems. There are three experimental Halls which can run simultaneously with three interleaved 499 MHz bunch trains and RF separators. Operation with simultaneous beams to two Halls is now routine, and simultaneous three beam operation has been demonstrated. The maximum design current per bunch train (120 {micro}A) has been achieved. Hall B eventually requires beam currents as low as 1 nA (200 pA has been delivered) simultaneous with delivery of up to 200 {micro}A to the other Halls. The required beam current ratio of 10,000 has been achieved; development of 1 nA beam position monitors continues.

RF and magnet system configuration and monitoring tools are being implemented at Jefferson Lab to improve system reliability and reduce operating costs. They are prototype components of the Momentum Management System being developed. The RF is of special interest because it affects the momentum and momentum spread of the beam, and because of the immediate financial benefit of managing the klystron DC supply power. The authors describe present and planned monitoring of accelerating system parameters, use of these data, RF system performance calculations, and procedures for magnet configuration for handling beam of any of five beam energies to any of three targets.

Films with layers of Nb, Cu, and Sn have been fabricated to simulate a Nb{sub 3}Sn bronze-type process. These Nb{sub 3}Sn films have produced critical current densities greater than 1 x 10{sup 6} A/cm{sup 2} at 4.2 K and 7.5 T. Niobium films doped with Y, Sc, Dy, Al{sub 2}O{sub 3}, and Ti have been deposited with e-beam co-evaporation onto 75 mm diameter Si wafers with a 100 nm SiO{sub 2} buffer layer. The Nb layer was followed by a layer of Cu and a layer of Sn to complete the bronze-type process. The films with the highest J{sub c} had about 8 vol. % Sc and about 18 vol. % Al{sub 2}O{sub 3}. Characterization of the microstructure by TEM shows that these high J{sub c} films contained high density of inclusions about 5 nm in size and that the grain size of the Nb{sub 3}Sn is about 20-25 nm for samples heat treated at 700 C for up to eight hours.

The Cable Measuring Engine (CME) is a tool which measures and records the cable dimensions in a nondestructive fashion. It is used in-line with the superconductor cable as it is being made. The CME is intended to be used as a standard method of measuring cable by the various manufacturers involved in the cable process.

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Some recent developments in the weakly-coupled heterotic string phenomenology are reviewed. We discuss several important issues such as dilaton/moduli stabilization, supersymmetry breaking (by hidden-sector gaugino condensation), gauge coupling unification (or the Newton's constant), the QCD axion, as well as cosmological problems involving the dilaton/moduli and the axion.

The four connections for the control dewar and VLPC bayonet can platform are designed, using finite element analysis, to carry all dead weight and live loads. Based on the loads applied to the platform, two 1 inch thick plates and two 3/4 inch thick brackets made of ASTM A572-Grade 42 are required. The 1 inch thick plate requires a 3/8 inch thick intermediate steel material, between the 8-inch x 4-inch x 1/4-inch boom and the plate, for load reinforcement as well as weld area reinforcement. Both the plates and the brackets require 3/4 inch steel bolt connections.

In the rush to explore the B system, one should not ignore the potential of rare K decays. The charged and neutral FCNC K {yields} {pi}{nu}{bar {mu}} decays are theoretically very clean, on a par with B {yields} {psi}K{sub S}, which measures {beta}, and much less problematic than B {yields} {pi}{pi} and B{sub s} {yields} K{sup +}K{sup -} or B{sub s} {yields} K*{sup +}K*{sup -} which have been proposed to measure {alpha} and {gamma} respectively. B(K{sup +} {yields} {pi}{sup +}{nu}{bar {nu}}), which in the Standard Model yields information on |V*{sub ts}V{sub td}|, is closely related to the ratio of B{sub d} - {bar B}{sub d} to B{sub s}-{bar B}{sub s}, mixing, which yields |V{sub td}/V{sub ts}|. It is essential to compare such clean measurements from the B and K sectors, because new physics is likely to manifest itself in apparent disagreements[12]. Measuring the branching ratios of K {yields} {pi}{nu}{bar {nu}} decays is a challenge, but the current proven reach in sensitivity for the charged mode and the prospect of measuring the neutral mode at AGS-2000 indicate that this window into flavor physics is on the verge of becoming an exploitable reality.

In the process of coal cleaning operations, a significant amount of coal is washed away as waste into the ponds. Clearly, such a large quantity of dumped coal fines has a detrimental effect on the environment. This investigation presents in innovative approach to recover and utilize waste coal fines from the preparation plant effluent streams and tailing ponds. Due to the large moisture content of the recovered coal fines, this study is focused on the utilization of coal fines in the coal-water slurry fuel (CWSF). The CWSF consists of 53.3% weight solids with a viscosity of less than 500 centipoise and 80-90% of solids passing 200 mesh. The 53.3% weight solids constitute a blend of 15% effluent recovered coal fines and 85% clean coal. It is the authors premise that a blend of plant coal and recovered waste coal fines can be used to produce a coal-water slurry fuel with the desired combustion characteristics required by the industry. In order to evaluate these characteristics the coal-water slurry fuel is fired in a test furnace at three firing rates (834,330 Btu/hr, 669,488 Btu/hr and 508,215 Btu/hr) with three different burner settings for each firing rate. Combustion tests were conducted to determine …

Coal cleaning is a technology that can solve a broad array of environmental problems associated with older, state-of-the-art, and future electric generating stations. Coal cleaning provides many environmental benefits. It reduces the concentration of inorganic minerals and elements found in association with coal, some of which are potentially toxic even though they are found in coal in only trace amounts. Currently, more sulfur and related S0{sub 2}, is removed by coal cleaning than by all post-combustion technologies combined. By increasing thermal efficiency and reducing parasitic power requirements, coal cleaning reduces all power plant emissions per unit of electricity produced, including S0{sub 2}, NO{sub x} C0{sub 2}, and hazardous air pollutant precursors (HAPs). While coal cleaning is a mature technology, in the past coal cleaning has only been used for the comparatively simple purposes of removing ash-forming and sulfur-bearing minerals. The application of this technology to H APs control will require a more sophisticated approach, based on a fundamental understanding of the mechanisms of trace element removal. The trace elements named as HAPs in the 1990 Amendments to the Clean Air Act can occur in coal in numerous forms. For example, antimony is believed to be present in pyrite, accessory sulfides …

This paper describes the design and fabrication of a vacuum pumping system for the ATP/LEDA (Low Energy Demonstration Accelerator) RFQ (Radio Frequency Quadrupole) linac. Resulted from the lost proton beam, gas streaming from the LEBT (Low Energy Beam Transport) and out-gassing from the surfaces of the RFQ cavity and vacuum plumbing, the total gas load will be on the order of 7.2 x 10{sup -4} Torr-liters/sec, consisting mainly of hydrogen. The system is designed to pump on a continual basis with redundancy to ensure that the minimal operating vacuum level of 1 x 10{sup -6} Torr is maintained even under abnormal conditions. Details of the design, performance analysis and the preliminary test results of the cryogenic pumps are presented.

Prior to the current project, development of the DSRP was done in a laboratory setting, using synthetic gas mixtures to simulate the regeneration off-gas and coal gas feeds. The objective of the current work is to further the development of zinc titanate fluidized-bed desulfurization (ZTFBD) and the DSRP for hot-gas cleanup by testing with actual coal gas. The objectives of this project are to: (1) Develop and test an integrated, skid-mounted, bench-scale ZTFBD/DSRP reactor system with a slipstream of actual coal gas; (2) Test the bench-scale DSRP over an extended period with a slipstream of actual coal gas to quantify the degradation in performance, if any, caused by the trace contaminants present in coal gas (including heavy metals, chlorides, fluorides, and ammonia); (3) Expose the DSRP catalyst to actual coal gas for extended periods and then test its activity in a laboratory reactor to quantify the degradation in performance, if any, caused by static exposure to the trace contaminants in coal gas; (4) Design and fabricate a six-fold larger-scale DSRP reactor system for future slipstream testing; (5) Further develop the fluidized-bed DSRP to handle high concentrations (up to 14 percent) of SO{sub 2} that are likely to be encountered when …

The mathematical models and numerical methods employed by the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multi-component flow in porous media, are described. The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The component models of FEHM are discussed. The first major component, Flow- and Energy-Transport Equations, deals with heat conduction; heat and mass transfer with pressure- and temperature-dependent properties, relative permeabilities and capillary pressures; isothermal air-water transport; and heat and mass transfer with noncondensible gas. The second component, Dual-Porosity and Double-Porosity/Double-Permeability Formulation, is designed for problems dominated by fracture flow. Another component, The Solute-Transport Models, includes both a reactive-transport model that simulates transport of multiple solutes with chemical reaction and a particle-tracking model. Finally, the component, Constitutive Relationships, deals with pressure- and temperature-dependent fluid/air/gas properties, relative permeabilities and capillary pressures, stress dependencies, and reactive and sorbing solutes. Each of these components is discussed in detail, including purpose, assumptions and …

The overall objective of this project was to learn more about controlling emissions of hazardous air pollutants (HAPs) from coal-fired power plants that are equipped with wet flue gas desulfurization (FGD) systems. The project was included by FETC as a Phase I project in its Mega-PRDA program. Phase I of this project focused on three research areas. These areas in order of priority were: (1) Catalytic oxidation of vapor-phase elemental mercury; (2) Enhanced particulate-phase HAPs removal by electrostatic charging of liquid droplets; and (3) Enhanced mercury removal by addition of additives to FGD process liquor. Mercury can exist in two forms in utility flue gas--as elemental mercury and as oxidized mercury (predominant form believed to be HgCl{sub 2}). Previous test results have shown that wet scrubbers effectively remove the oxidized mercury from the gas but are ineffective in removing elemental mercury. Recent improvements in mercury speciation techniques confirm this finding. Catalytic oxidation of vapor-phase elemental mercury is of interest in cases where a wet scrubber exists or is planned for SO{sub 2} control. If a low-cost process could be developed to oxidize all of the elemental mercury in the flue gas, then the maximum achievable mercury removal across the existing …

The objective of this project to develop an advanced flue gas desulfurization (FGD) process that has decreased capital and operating costs, higher SO{sub 2} removal efficiency, and better by-product solids quality than existing, commercially available technology. A clear liquor process (which uses a scrubbing liquid with no solids) will be used to accomplish this objective rather than a slurry liquor process (which contains solids). This clear liquor scrubbing (CLS) project is focused on three research areas: (1) Development of a clear liquor scrubbing process that uses a clear solution to remove SO{sub 2} from flue gas and can be operated under inhibited-oxidation conditions; (2) Development of an anhydrite process that converts precipitated calcium sulfite to anhydrous calcium sulfate (anhydrite); and (3) Development of an alkali/humidification process to remove HCl from flue gas upstream of the FGD system. The anhydrite process also can be retrofit into existing FGD systems to produce a valuable by-product as an alternative to gypsum. This fits well into another of FETC's PRDA objectives of developing an advanced byproduct recovery subsystem capable of transforming SO{sub 2} into a useable byproduct or high-volume valuable commodities of interest. This paper describes the proposed processes, outlines the test approach, and …

This project reactivates ARCO�s idle Pru Fee property in the Midway-Sunset field, California and conducts a continuous steamflood enhanced oil recovery demonstration aided by an integration of modern reservoir characterization and simulation methods. Cyclic steaming was used to reestablish baseline production within the reservoir characterization phase of the project. During the demonstration phase begun in January 1997, a continuous steamflood enhanced oil recovery was initiated to test the incremental value of this method as an alternative to cyclic steaming. Other economically marginal Class III reservoirs having similar producibility problems will benefit from insight gained in this project. The objectives of the project are: (1) to return the shut-in portion of the reservoir to optimal commercial production; (2) to accurately describe the reservoir and the recovery process; and (3) to convey the details of this activity to the domestic petroleum industry, especially to other producers in California, through an aggressive technology transfer program.

This study aims at the development of an effective nondestructive evaluation technique to predict the remaining useful life of a ceramic candle filter during a power plant's annual maintenance shutdown. The objective of the present on-going study is to establish the vibration signatures of ceramic candle filters at varying degradation levels due to different operating hours, and to study the various factors involving the establishment of the signatures.

Experimental and theoretical evidence for the nonequilibrium Zeldovich-von Neumann-Doring (NEZND) theory of self-sustaining detonation is presented. High density, high temperature transition state theory is used to calculate unimolecular reaction rate constants for the initial decomposition of gaseous norbornene, liquid nitromethane, and solid, single crystal pentaerythritol tetranitrate as functions of shock temperature. The calculated rate constants are compared to those derived from experimental induction time measurements at various shock and detonation states. Uncertainties in the calculated shock and von Neumann spike temperatures are the main drawbacks to calculating these reaction rates. Nanosecond measurements of the shock temperatures of unreacted explosives are necessary to reduce these uncertainties.

Ash behavior in power systems can have a significant impact on the design and performance of advanced power systems. The Energy & Environmental Research Center (EERC) has focused significant effort on ash behavior in conventional power systems that can be applied to advanced power systems. This initiative focuses on filling gaps in the understanding of fundamental mechanisms of ash behavior that has relevance to commercial application and marketable products. This program develops methods and means to better understand and mitigate adverse coal ash behavior in power systems and can act to relieve the U.S. reliance on diminishing recoverable oil resources, especially those resources that are not domestically available and are fairly uncertain.

Heat flow in a cylinder with internal heating is used as a basis for deriving a simple theory of detonation front curvature, leading to the prediction of quadratic curve shapes. A thermal conductivity of 50 MW/mm{sup 2} is found for TATB samples.

The objective of this study is to develop a second generation HGD process that regenerates the sulfided sorbent directly to elemental sulfur using SO{sub 2}, with minimal consumption of coal gas. The goal is to have better overall economics than DSRP when integrated with the overall IGCC system.

The electrostatic comb finger drive has become an integral design for microsensor and microactuator applications. This paper reports on utilizing the levitation effect of comb fingers to design vertical-to-the-substrate actuation for interferometric applications. For typical polysilicon comb drives with 2 {micro}m gaps between the stationary and moving fingers, as well as between the microstructures and the substrate, the equilibrium position is nominally 1-2 {micro}m above the stationary comb fingers. This distance is ideal for many phase shifting interferometric applications. Theoretical calculations of the vertical actuation characteristics are compared with the experimental results, and a general design guideline is derived from these results. The suspension flexure stiffnesses, gravity forces, squeeze film damping, and comb finger thicknesses are parameters investigated which affect the displacement curve of the vertical microactuator. By designing a parallel plate capacitor between the suspended mass and the substrate, in situ position sensing can be used to control the vertical movement, providing a total feedback-controlled system. Fundamentals of various capacitive position sensing techniques are discussed. Experimental verification is carried out by a Zygo distance measurement interferometer.

Commensurability effects between the superconducting flux line lattice and a square lattice (period d=1{micro}m and diameter D=0.4{micro}m) of submicron holes in 1500 {angstrom} vanadium films were studied by atomic force microscopy, DC magnetization, AC susceptibility, magnetoresistivity and I-V measurements. Peaks in the magnetization and critical current at matching fields are found to depend nonlinearly upon the value of external AC field or current, as well as the inferred symmetry of the flux line lattice.