A new technique is presented in this paper that reduces the complexity of state differential equations while accounting for modeling assumptions. The mismatch controls are defined as the differences between the model equations and the true state equations. The performance index of the optimal control problem is formulated with a set of tuning parameters that are user-selected to tune the control solution in order to achieve the best results. Computer simulations demonstrate that the tuned control law outperforms the untuned controller and produces results that are comparable to a numerically-determined, piecewise-linear optimal controller.

This document contains several abstracts of talks given to `Opportunity `95 - Environmental Technology Through Small Business.` Titles include the following: Pyrolysis of Plastic Waste; Subcritical water extraction of organic pollutants and extraction of hazardous metals from mixed solid wastes by chelation and supercritical fluid extraction; extraction and analysis of pollutant organics from contaminated solids using off-line supercritical fluid extraction and on-line SFE/IR; Stabilization of vitrified waste by enhanced crystallization and development of a protocol to predict long-term stability.

This report emphasizes the features of the United States Tritium Facility operation at the Savannah River Site. It outlines the buildings that represent the facility operating basis. It explores areas where new technology and proven methods of operation developed at the Site have made dramatic environmental and facility work enhancements over the last several years. These enhancements should be consideration for future facility designs and for any current tritium missions.

We show how non-instantaneous nonlinearities can be used to characterize an ultrashort pulse in an extension of the Frequency-Resolved Optical Gating technique. We demonstrate this principle using the Raman effect in fused silica.

Silicon solar cell efficiencies of 17.1%, 16.4%, 14.8%, and 14.9% have been achieved on FZ, Cz, multicrystalline (mc-Si), and dendritic web (DW) silicon, respectively, using simplified, cost-effective rapid thermal processing (RTP). These represent the highest reported efficiencies for solar cells processed with simultaneous front and back diffusion with no conventional high-temperature furnace steps. Appropriate diffusion temperature coupled with the added in-situ anneal resulted in suitable minority-carrier lifetime and diffusion profiles for high-efficiency cells. The cooling rate associated with the in-situ anneal can improve the lifetime and lower the reverse saturation current density (J{sub 0}), however, this effect is material and base resistivity specific. PECVD antireflection (AR) coatings provided low reflectance and efficient front surface and bulk defect passivation. Conventional cells fabricated on FZ silicon by furnace diffusions and oxidations gave an efficiency of 18.8% due to greater short wavelength response and lower J{sub 0}.

Performance of electric vehicles (EVs) is being studied in an ongoing Site Operator Program, as part of the Electric and Hybrid Vehicle Program supported by the U.S. Department of Energy (DOE). More than 200 EVs are being operated by Site Operators in various geographical and climatic regions of the United States. Cold-weather operation of EVs is of particular interest. As expected, low temperatures affect a battery`s ability to accept a charge, which decreases EV range and increases operating costs. Battery types other than lead-acid are being evaluated such as nickel-iron, gelled electrolyte lead-acid, nickel-cadmium, and sodium-sulfur. Also, improved methods of collecting EV performance data are being implemented, thermal management systems are being tested, and a prototype ultracapacitor is being tested as a possible alternative to conventional batteries.

This analysis of the plutonium oxide/metal storage containers is in support of the design and testing project The results from the dynamic analysis show some important facts that have not been considered before. The internal bagless transfer can will have higher stress than the primary container. The quasi-static analysis provides a conservative solution. In both vertical upright drop (dynamic) and inclined upside down drop (quasi-static) the containers are structurally sound.

Sampling during environmental drilling is essential to fully characterize the spatial distribution and migration of near surface contaminants. However, the analysis of these samples is not only expensive, but can take weeks or months when sent to an off-site laboratory. In contrast, measurement-while-drilling (MWD) screening capability could save money and valuable time by quickly distinguishing between contaminated and uncontaminated areas. Real-time measurements provided by a MVM system would enable on-the-spot decisions to be made regarding sampling strategies, enhance worker safety, and provide the added flexibility of being able to ``steer`` the drill bit in or out hazardous zones. During measurement-while-drilling, down-hole sensors are located behind the drill bit and linked by a rapid data transmission system to a computer at the surface. As drilling proceeds, data are collected on the nature and extent of the subsurface contamination in real-time. The down-hole sensor is a Geiger-Mueller tube (GMT) gamma radiation detector. In addition to the GMT signal, the MWD system monitors these required down-hole voltages and two temperatures associated with the detector assembly. The Gamma Ray Detection System (GRDS) and electronics package are discussed in as well as the results of the field test. Finally, our conclusions and discussion of future …

In this paper we investigate the physical controls upon the rate of vaporization of liquid as it is injected into a porous layer containing superheated vapor. We develop a simple model of the process and show that if liquid is injected at a relatively high rite, a small fraction of the liquid vaporizes and the porous layer becomes filled with hot liquid. In contrast, at low rates of injection a large fraction of the liquid may vaporize. We also describe a new and fundamental instability that can develop at a migrating liquid-vapour interface if the rite of injection is sufficiently small. This phenomenon is manifest in the form of liquid fingers growing from a liquid-vapour interface and is investigated through the use of analytical, experimental and numerical techniques.

SEMATECH and the Department of Energy have established a Contamination Free Manufacturing Research Center (CFMRC) located at Sandia National Laboratories. One of the programs underway at the CFMRC is directed towards defect reduction in semiconductor process reactors by the application of computational modeling. The goal is to use fluid, thermal, plasma, and particle transport models to identify process conditions and tool designs that reduce the deposition rate of particles on wafers. The program is directed toward defect reduction in specific manufacturing tools, although some model development is undertaken when needed. The need to produce quantifiable improvements in tool defect performance requires the close cooperation among Sandia, universities, SEMATECH, SEMATECH member companies, and equipment manufacturers. Currently, both plasma (e.g., etch, PECVD) and nonplasma tools (e.g., LPCVD, rinse tanks) are being worked on under this program. In this paper the authors summarize their recent efforts to reduce particle deposition on wafers during plasma-based semiconductor manufacturing.

Maintaining proficiency in carrying out mission goals is fundamental to the success of any organization. The definitive mission of the Waste Management and Remedial Action Division (WMRAD) of Oak Ridge National Laboratory (ORNL) is {open_quotes}to conduct waste management activities in a compliant, publicly acceptable, technically sound, and cost-efficient manner{close_quotes}. In order to effectively fulfill this mission, must meet or exceed several standards in respect to our customers. These include: (1) identifying current and future customer expectations; (2) managing our relationships with our customers; (3) ensuring our commitment to our customers; and (4) measuring our success m customer satisfaction. Our customers have a great variety of requirements and expectations. Many of these are in the form of local, state, and federal regulations and environmental standards. Others are brought to our attention through inquires made to the Department of Energy (DOE).Consumer surveys have proven to be effective tools which have been used to make improvements, enhance certain program elements, and identify beneficial areas in already existing programs. In addition, national working groups, technology transfer meetings, and manager/contractor`s meeting offer excellent opportunities to assess our activities.

Chemical probes have been developed to provide insight into the geometrical structure of isolated transition metal clusters. By determining as a function of cluster size the number of adsorbate molecules that saturate a cluster, and/or the binding energy of molecules to cluster surfaces, it is often possible to propose geometrical structures consistent with the experimental observations. The authors review recent studies of the reactions of cobalt, nickel, and copper clusters with ammonia, water, and nitrogen that provide structural information. It is found that small (between 50 and 150 atoms) cobalt, nickel, and copper clusters generally adopt icosahedral packing. However, for even smaller (less than 20 atoms) clusters, cobalt and nickel differ in their structure. The authors also see evidence for adsorbate-induced structural changes. These changes may allow the properties of materials fabricated from such clusters to be tailored to specific needs. A preliminary illustration of the dramatic effect that heteroatoms can have on metal cluster chemical properties is presented.

We present magnetoluminescence data which provides a quantitative measure of the energy-band dispersion curves of novel compound semiconductor optoelectronic materials. Data for a n-type strained-layer InGaAs/GaAs (quantum-well width {approximately} 8 nm) and a n-type 4.5-nm-wide GaAs/AlGaAs lattice-matched single-quantum well are presented. We find that the -conduction-bands are almost parabolic, with a mass of about 0.068m{sub 0} for InGaAs/GaAs and 0.085m{sub 0} for the GaAs/AlGaAs structure. The valence-bands are nonparabolic with wave vector dependent in-plane valence-band masses varying from about 0.1 m{sub 0} at zone center to about 0.3 m{sub 0} for 20 meV energies.

Inertial force damping control by micro manipulator modulation is proposed to suppress the vibrations of a micro/macro manipulator system. The proposed controller, developed using classical control theory, is added to the existing control system. The proposed controller uses real-time measurements of macro manipulator flexibility to adjust the motion of the micro manipulator to counteract structural vibrations. Experimental studies using an existing micro/macro flexible link manipulator testbed demonstrate the effectiveness of the proposed approach to suppression of vibrations in the macro/micro manipulator system using micro-manipulator-based inertial active damping control.

The effect of the pump, signal, and idler wave phases on three-wave nonlinear parametric mixing is investigated in a series of single-pass-gain experiments. Measurements are made with two angle-tuned KTP crystals in a 532 nm pumped, walkoff-compensated, optical parametric amplifier that is seeded by an 800 nm cw diode laser. In one of the measurements the second crystal is orientated to have its effective nonlinearity d{sub eff.} of opposite sign to that of the first crystal, so that all mixing that occurred in the first crystal is cancelled by the second when the phase mismatch {Delta}k{sub crystal 1} = {Delta}k{sub crystal 2} = 0. Efficient two-crystal amplification is subsequently restored by selecting the correct phase relationship for the three waves entering the crystal by inserting a dispersive plate between the crystals. The experimental results are explained in a straightforward manner with diagrams involving the three input wave polarizations. These results demonstrate that walkoff-compensated geometries require phase correction to achieve efficient mixing in the second crystal whenever the nonlinear interaction involves two extraordinary waves (e-waves). One practical application of this work may be lower oscillation thresholds and enhanced performance in walkoff-compensated optical parametric oscillators which use two e-waves.

ELIPGRID-PC, a new personal computer program, has been developed to provide easy access to Singer`s ELIPGRID algorithm for hot-spot detection probabilities. Three features of the program are the ability to determine: (1) the grid size required for specified conditions, (2) the smallest hot spot that can be sampled with a given probability, and (3) the approximate grid size resulting from specified conditions and sampling cost. ELIPGRID-PC also provides probability of detection versus cost data for graphing with spreadsheets or graphics software. The program has been successfully tested using Singer`s published ELIPGRID results. An apparent error in the published ELIPGRID code has been uncovered and an appropriate modification incorporated into the new program.

The visualization of fluid flows has become more challenging, as recent advancements in computational methods have increased the complexity and size of simulations. Our objective is to develop a flexible flow visualization tool for fluid simulations that include the full physics and geometrical complexities found in modeling practical combustion systems, such as internal combustion engines. The challenges to flow visualization come from: (1) the large simulation output, especially when using massively parallel computers; (2) the increasingly complex geometries that include moving surfaces such as pistons and valves; (3) the complex physical phenomena in realistic problems of fuel injection, combustion fronts, boundary flows, and large scale turbulence; and (4) the numerical complexity of indirect addressing of computational elements, variable mesh connectivity, distorted elements, and moving meshes. We have developed a visualization program that addresses these complexities. The program was developed as a post-processor to the KIVA family of codes for reactive flow simulations. Because of the complexity of the KIVA codes, the visualization program is very versatile and applicable to any code with meshes of arbitrary hexahedrons. No comparable commercial visualization package could be found. To visualize the fluid flow, we use mass-less tracer particles that follow the movement of the …

The Energy and Environmental Research Corporation (EER), the Ohio Agricultural Research and Development Center (OARDC), the Will-Burt Company (W-B) and the U.S. Department of Energy (DOE) have successfully developed and completed pilot plant tests on a small scale atmospheric fluidized bed combustion (AFBC) system. This system can be used to generate electricity, and/or hot water, steam. Following successful pilot plant operation, commercial demonstration will take place at Cedar Lane Farms (CLF), near Wooster, Ohio. The system demonstration will be completed by the end of 1995. The project is being funded through a cooperative effort between the DOE, EER, W-B, OARDC, CLF and the Ohio Coal Development Office (OCDO). The small scale AFBC, has no internal heat transfer surfaces in the fluid bed proper. Combining the combustor with a hot air gas turbine (HAGT) for electrical power generation, can give a relatively high overall system thermal efficiency. Using a novel method of recovering waste heat from the gas turbine, a gross heat rate of 13,500 Btu/kWhr ({approximately}25% efficiency) can be achieved for a small 1.5 MW, plant. A low technology industrial recuperation type gas turbine is used that operates with an inlet blade temperature of 1450{degrees}F and a compression ratio of …

Treatment of spent nuclear fuel at Argonne National Laboratory consists of a pyroprocessing scheme in which the development of suitable waste forms is being advanced. Of the two waste forms being proposed, metal and mineral, the production of the metal waste form utilizes induction melting to stabilize the waste product. Alloying of metallic nuclear materials by induction melting has long been an Argonne strength and thus, the transition to metallic waste processing seems compatible. A test program is being initiated to coalesce the production of the metal waste forms with current induction melting capabilities.

Damage mechanisms may occur during the transmission of Q-switched, Nd/YAG laser pulses through fused silica fibers. Fiber end-face characteristics, laser characteristics, and aspects of the laser-to-fiber injection typically determine dominant damage mechanisms. However, an additional damage process has been observed at internal sites where fibers were experiencing significant local stresses due to fixturing or bends in the fiber path. A transmission reduction prior to damage was typically not measurable at these sites. Damage would not always occur during initial testing, but sometimes occurred later in time at laser levels that previously had been transmitted without damage. In these cases the time at stress appeared to be more important than the number of transmitted shots prior to damage. A possible relation between internal damage thresholds at stressed sites and the total time under stress is suggested by the fact that silica fibers experience static fatigue processes. These processes involve the slow growth of local defects under tensile stress at rates that depend upon environmental conditions. Defects reaching sufficient size and having appropriate location could be sites for reduced laser-induced damage thresholds. The present work looks into the possibility that static fatigue processes can affect damage thresholds. The experiments used a laser …

The objective of this program is to develop improved protective clothing for use by workers engaged in decomissioning and decontamination of former DOE sites. The proposed technology concerns a new protective clothing fabric that combines a permselective membrane layer (for water transmission and breathability) with a sorptive layer.

H-modes have been obtained for the first time in high temperature, high poloidal beta plasmas with significant tritium concentrations in TFTR. Tritium is provided mainly through high power neutral beam injection (NBI) with powers up to 28 MW and beam energies of 90--110 keV. Transition to a circular limiter H-mode has been obtained following a rapid ramp down of the plasma current. Some of the highest values of {tau}{sub E} have been achieved on TFTR during the ELM-free phase of these DT H-mode plasmas. {tau}{sub E} enhancements greater than four times L-mode have been achieved.

A mobile robot system called the Stored Waste Autonomous Mobile Inspector (SWAMI) is under development by the Savannah River Technology Center (SRTC) Robotics Group of Westinghouse Savannah River Company (WSRC) to perform mandated inspections of waste drums stored in warehouse facilities. The system will reduce personnel exposure to potential hazards and create accurate, high-quality documentation to ensure regulatory compliance and enhance waste management operations. Development work is coordinated among several Department of Energy (DOE), academic, and commercial entities in accordance with DOE`s technology transfer initiative. The prototype system, SWAMI I, was demonstrated at Savannah River Site (SRS) in November, 1993. SWAMI II is now under development for field trials at the Fernald site.

This paper describes a process of combining two state-of-the-art CFD tools, SPRINT and INCA, in a manner which extends the utility of both codes beyond what is possible from either code alone. The speed and efficiency of the PNS code, SPRING, has been combined with the capability of a Navier-Stokes code to model fully elliptic, viscous separated regions on high performance, high speed flight systems. The coupled SPRINT/INCA capability is applicable for design and evaluation of high speed flight vehicles in the supersonic to hypersonic speed regimes. This paper describes the codes involved, the interface process and a few selected test cases which illustrate the SPRINT/INCA coupling process. Results have shown that the combination of SPRINT and INCA produces correct results and can lead to improved computational analyses for complex, three-dimensional problems.