Deposition on indoor surfaces is an important removal mechanism for tobacco smoke particles. We report measurements of deposition rates of environmental tobacco smoke particles in a room-size chamber. The deposition rates were determined from the changes in measured concentrations by correcting for the effects of coagulation and ventilation. The air flow turbulent intensity parameter was determined independently by measuring the air velocities in the chamber. Particles with diameters smaller than 0.25 {micro}m coagulate to form larger particles of sizes between 0.25-0.5 {micro}m. The effect of coagulation on the particles larger than 0.5 {micro}m was found to be negligible. Comparison between our measurements and calculations using Crump and Seinfeld's theory showed smaller measured deposition rates for particles from 0.1 to 0.3 {micro}m in diameter and greater measured deposition rates for particles larger than 0.6 {micro}m at three mixing intensities. Comparison of Nazaroff and Cass model for natural convection flow showed good agreement with the measurements for particles larger than 0.1 {micro}m in diameter, however, measured deposition rates exceeded model prediction by a factor of approximately four for particles in size range 0.05-0.1 {micro}m diameter. These results were used to predict deposition of sidestream smoke particles on interior surfaces. Calculations predict that …

The testing of candidate fuel elements at prototypic operating conditions with respect to temperature, power density, hydrogen coolant flow rate, etc., a crucial component in the development and qualification of nuclear rocket engines based on the Particle Bed Reactor (PBR), NERVA-derivative, and other concepts. Such testing may be performed at existing reactors, or at new facilities. A scoping study has been performed to assess the feasibility of testing PBR based fuel elements at the TREAT reactor. initial results suggest that full-scale PBR, elements could be tested at an average energy deposition of {approximately}60--80 MW-s/L in the current TREAT reactor. If the TREAT reactor was upgraded to include fuel elements with a higher temperature limit, average energy deposition of {approximately}100 MW/L may be achievable.

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Space is an Application Visualization System (AVS) graphics module designed for crystallographic and molecular research. The program can handle molecules, two-dimensional periodic systems, and three-dimensional periodic systems, all referred to in the paper as models. Using several methods, the user can select atoms, groups of atoms, or entire molecules. Selections can be moved, copied, deleted, and merged. An important feature of Space is the crystallography component. The program allows the user to generate the unit cell from the asymmetric unit, manipulate the unit cell, and replicate it in three dimensions. Space includes the Buerger reduction algorithm which determines the asymmetric unit and the space group of highest symmetry of an input unit cell. Space also allows the user to display planes in the lattice based on Miller indices, and to cleave the crystal to expose the surface. The user can display important precalculated volumetric data in Space, such as electron densities and electrostatic surfaces. With a variety of methods, Space can compute the electrostatic potential of any chemical system based on input point charges.

In this paper we discuss the observed variation in plasma performance with plasma shape, in particular, we shall compare single and double null diverted plasmas. The product [beta][center dot][tau] has been used as a figure-of-merit for comparing different toroidal magnetic configurations. Here we shall use it as the figure-of-merit for comparing differing configurations within the DIII-D tokamak.

The development of technologically advanced, high-efficiency wind turbines continues to be a high-priority activity of the US wind industry. The National Renewable Energy Laboratory (formerly the Solar Energy Research Institute), sponsored by the US Department of Energy (DOE), has initiated the Advanced Wind Turbine Program to assist the wind industry in the development of a new class of advanced wind turbines. The initial phase of the program focused on developing conceptual designs for near-term and advanced turbines. The goal of the second phase of this program is to use the experience gained over the last decade of turbine design and operation combined with the latest existing design tools to develop a turbine that will produce energy at $0.05 per kilowatt-hour (kWh) in a 5.8-m/s (13-mph) wind site. Three contracts have been awarded, and two more are under negotiation in the second phase. The third phase of the program will use new innovations and state-of-the-art wind turbine design technology to produce a turbine that will generate energy at $0.04/kWh in a 5.8-m/s wind site. Details of the third phase will be announced in early 1993.

Fermilab has adopted the Source Evaluation Board (SEB) method for procuring certain major technical components of the Fermilab Main Injector. The SEB procedure is designed to ensure the efficient and effective expenditure of Government funds at the same time that it optimizes the opportunity for attainment of project objectives. A qualitative trade-off is allowed between price and technical factors. The process involves a large amount of work and is only justified for a very limited number of procurements. Fermilab has gained experience with the SEB process in awarding subcontracts for major subassemblies of the Fermilab Main Injector dipoles.

In order to understand the physicochemical mechanism involved in the organic semiconductor charge-transfer processes occurring upon doping of the films with vapor molecules different experimental approaches much be taken. The effect of vapor diffusion into the electrochemically deposited poly(pyrrole), PP and poly(N-vinylcarbazole), PNVCz, films was investigated by monitoring the mass change of the exposed polymer, absorbance changes in the absorption spectra, and the work function change due to the modulation of the Fermi level in the material. An important step in that investigation was to establish the link between the distribution of the active dopant within the surface and the bulk of the material (1).

Sintering shrinkage curves and phase changes were compared for calcium-substituted lanthanum chromates with either slight Asite enrichment or depletion. Of the former type, La[sub 0.7]Ca[sub 0.31],CrO[sub 3] that was synthesized by the glycine-nitrate method sintered to high density in air at 1250C, exhibiting two rapid-shrinkage events. Weight loss measurements corroborated XRD data showing that, prior to densiflcation, over half the Ca resided in non-perovskite phases, including CaCrO[sub 4]. In the La[sub 0.7]Ca[sub 0.31]CrO[sub 3], densification was closely associated with re-dissolution of the Ca into the perovskite.

The impedance budget of the Fermilab Main Injector (MI) is estimated, which includes the contributions from the resistive walls, bellows, rf cavities, steps, Lambertsons, etc. Beam stability during ramping and bunch coalescence is analyzed. The transverse resistive-wall coupled bunch growth is found to be somewhat worse than the situation in the Main Ring (MR).

As part of a general laboratory cleanup of hazardous materials from the accelerator enclosures we have replaced the liquid scintillator based paint can type beam loss monitors with improved loss monitors based on plastic centiliter. This paper describes the design of these counters and their performance in the PBAR source.

We report improvement of the polarization diagnostics and their use in the development of the Optically Pumped Polarized Ion Source (OPPIS).

Antiprotons in the debuncher ring at Fermilab have been observed to be bunched outside of the barrier bucket'' when cooled to small [Delta]p/p with the stochastic cooling. This bunching occurs in the same location as a very small stable bucket in the RF wave form. The stochastic cooling appears to be causing beam that is originally uniformly distributed to be captured by this stable bucket.

Collaborators on the design of a Tevatron Superconducting Linear Accelerator (TESLA) are working toward construction of a test cell consisting of four full length cryostats, 12 meters long, each containing eight, 9-cell superconducting rf cavities. In order to ensure that each cavity meets its performance requirements, [open quote]as received[close quote] structures will be tested in a vertical dewar prior to installation in the cryostat vessels. In addition, the dewar system will accommodate cavities installed in their helium containment vessels for testing if performance problems occur during later stages of fabrication. The vertical dewar system permits testing of the rf performance and high power processing of the cavity structures at their operating temperature of 1.8 K. The design of the cryogenic system, vacuum system, rf input, test instrumentation, and tuning system is described in detail.

An attempt was made to pursue [sup 129]Xe NMR as a pore measurement technique. Samples studied were synthetic imogolite (tubular aluminosilicate with gibbsite structure), sodium Y-zeolite, and an aerogel and a xerogel. Gases used were normal Xe, [sup 13]CO[sub 2], and [sup 15]N[sub 2]. Although a completely general NMR technique for measuring pore size distributions may not be possible, information about molecular motion and interactions can be obtained, because NMR is sensitive to short range interactions (1 nm or less) and to molecular dynamics in the range 10[sup [minus]2] to 10[sup [minus]6]s.

The fast magnetosonic wave is now recognized to be a leading candidate for noninductive for the tokamak reactor due to the ability of the wave to penetrate to the hot dense core region. Fast wave current drive (FWCD) experiments on D3D have realized up to 120 kA of rf current drive, with up to 40% of the plasma current driven noninductively. The success of these experiments at 60 MHZ with a 2 MW transmitter source capability has led to a major upgrade of the FWCD system. Two additional transmitters, 30 to 120 NM, with a 2 MW source capability each, will be added together with two new four-strap antennas in early 1994. Another major thrust of the D3-D program is to develop advanced tokamak modes of operation, simultaneously demonstrating improvements in confinement and stability in quasi-steady-state operation. In some of the initial advanced tokamak experiments on D3-D with neutral beam heated (NBI) discharges it has been demonstrated that energy confinement nine can be improved by rapidly elongating the plasma to force the current density profile to be more centrally peaked. However, this high-l[sub i] phase of the discharge with the commensurate improvement in confinement is transient as the current density …

New lightweight materials continue to be of great interest to the automotive industry. Compared to 20 years ago, the average vehicle weight has been reduced by almost a fourth, and fuel economy has nearly doubled. While continued improvements are both desirable and possible, materials choices are narrowing and the manufacturing methods needed to produce advanced materials systems are much more costly. The incentives remain high, however; particularly in view of large payoffs associated with minimizing structural weight in electric and hybrid-type vehicles. One generic solution is to develop coatings that will enable the use of lower cost materials. A workshop on coatings needs in the auto industry was held in Detroit, Michigan on October 27 and 28, 1992 with the objective of identifying research needs where coatings could enhance the use of energy efficient lightweight materials for automotive applications. Four generic areas had previously been identified auto manufacturers and industry suppliers. These were: Wear Coatings, Hard Protective Coatings for Plastics, Solar Control Coatings, and Process Manufacturing Issues. The development of coatings and coating technologies for lightweight metals and metal matrix composites emerged as the number one research needs. This need underscores the interest in making better use of existing lightweight …

Ahlstrom Pyropower has designed and built a 10 MW[sub th] (34 MMBtu) pressurized circulating fluidized bed (PCFB) pilot plant in Karhula, Finland. The unit is now operating. Data from this unit supports the design of a nominal 80 MW, Des Moines Energy Center 1 (DMEC-1) PCFB Repowering Project. The pilot plant PCFB combustor is of square cross-section. It is housed in a 3.6 m (11.8 ft) diameter pressure vessel. A high pressure high temperature gas cleaning unit downstream of the PCFB exhaust is installed in a separate 2.6 m (8.5 ft) diameter pressure vessel. The maximum plant operating pressure is 16 bar (232 psia). The fuel is fed in slurry form; sorbent is also fed along with the fuel. The net heat input per unit cross section of the combustor is the highest of any known combustion mode. The heat release can go up to 40 MW/m[sup 2] (12.6 MMBtu/ft[sup 2] hr). Many types of coals including high sulfur, bituminous Illinois No. 6 coal and Western sub bituminous, low sulfur Powder River Basin coal were tested. Combustion efficiencies in the range of 99.5 to 99.9% have been consistently observed. Emissions of various gases such as NO[sub x] SO[sub 2] and …

Many applications of solar energy require large mirrors to provide high levels of concentrated sunlight. The success of such conversion systems hinges on the optical durability and economic viability of the reflector materials. A major effort at the National Renewable Energy Laboratory (NREL) has been to improve the existing reflector materials technology and to identify candidates that retain optical performance and durability criteria and offer potential for reduced cost. To attain the goals, it is desirable to maintain and increase the involvement of industrial organizations in reflective materials R D related to the conversion of solar resources to useful energy. Toward this end, NREL has recently initiated several collaborative efforts with industry to develop advanced reflector materials.

A prototype beam halo detector of scintillating Fibers has been designed in order to detect beam halo problems at an early stage in the tuning process. The results of initial characterization of the fibers are presented and issues of electronics and readout discussed.

In a new hydrodynamic formulation of shock-induced chemical reaction, we can show formally that the presence of certain homogenous reaction characteristics is becoming more evident as shock pressure increase even in heterogeneous high explosives. The homogeneous reaction pathway includes nonequilibrium excitation and deactivation stages prior to chemical reaction. The excitation process leads to an intermediate state at higher energy level than the equilibrium state, and as a result, the effective activation energy appears to be lower than the value based on thermal experiments. As the pressure goes up higher, the homogeneous reaction can even surpass the heterogeneous process and becomes the dominant mechanism.

Landfill No. 4 and the sludge lagoon at Robins Air Force Base, Warner Robins, Georgia, were added to the United States Environmental Protection Agency (EPA) National Priorities List in 1987 because of highpotential for contaminant migration. Warner Robins is located approximately 90 miles southeast of Atlanta. In 1990 CH2M HILL conducted a Remedial Investigation at the base that recommended that further ecological assessment investigations be conducted (CH2M HILL 1990). The subject paper is the result of this recommendation. The ecological study was carried out by the Hazardous Waste Remedial Actions Program (HAZWRAP)Division of Martin Marietta Energy Systems, Inc., working jointly with its subcontractor CDM (CDM 1992a). The primary area of investigation (Zone 1) included the sludge lagoon, Landfill No. 4, the wetland area east of the landfill and west of Hannah Road (including two sewage treatment ponds), and the area between Hannah Road and Horse Creek (Fig. 1). The bottomland forest wetlands of Zone 1 extend from the landfill east to Horse Creek. Surface water and groundwater flow across Zone 1 is generally in an easterly direction toward Horse Creek. Horse Creek is a south-flowing tributary of the Ocmulgee River Floodplain. The objective of the study was to perform a …

Synthesizing oxide ceramic powders by application of a microwave plasma is of great advantage. The microwave plasma can be used two ways: To act as a source of heat for the pyrolysis of solutions and to excite gas phase reactions to obtain nanosized powders. Both applications are superior to standard methods. A microwave cavity well suited for these experiments and its operating characteristics are described. Using a microwave plasma as a source of heat for pyrolytic decomposition of nitrates in aqueous solutions leads to a fine grained product with particle sizes from 100 to 1000 nm. Crystallite sizes in those particles are in most cases less than 10 nm. This is demonstrated with zirconia-based ceramics, such as ZrO{sub 2} -- 3m% Y{sub 2}O{sub 3} -- 20m% Al{sub 2}O{sub 3}, Depending on conditions during pyrolysis, it is possible to obtain a product in which alumina is either dissolved in zirconia or the onset of the phase separation is observed. Energy efficiency for this process is better than 80%. If the reactants are gaseous e.g., ZrCl{sub 4} it is possible to produce powders with mean crystallite sizes of about 4 nm. In the case of zirconia these particles are nanocrystalline with a …

Los Alamos facilities containing significant radiological hazards have been reclassified according to DOE-SID 1027-92, a recently issued guide for hazard classification. DOE-STD 1027-92 was provided in support of DOE Order 5480.23 to identify which facilities would be governed under DOE 5480.23 requirements; these would presumably be called nuclear facilities. This new classification has affected the original list of 18 LANL nuclear facilities by increasing it to 39. It has also lowered the classification of TA-55-4, the plutonium processing facility containing highest intrinsic hazard at LANL, from the highest classification to an intermediate classification. This presentation addresses the impact of these changes in the nuclear facility list in the areas of radiological health, safety analysis documentation, and risk management.