The Power Systems Development Facility (PSDF) is a joint Department of Energy/Industry sponsored engineering-scale facility for testing advanced coal-based power generation technologies. High temperature, high pressure gas cleaning is critical to many of these advanced technologies. Barrier filter elements that can operate continuously for nearly 9000 hours are required for a successful gas cleaning system for use in commercial power generation. Since late 1999, the Kellogg Brown & Root Transport reactor at the PSDF has been operated in gasification mode. This paper describes the test results for filter elements operating in the Siemens-Westinghouse particle collection device (PCD) with the Transport reactor in gasification mode. Operating conditions in the PCD have varied during gasification operation as described elsewhere in these proceedings (Martin et al, 2002).

Understanding global-scale ecosystem responses to changing environmental conditions is important both as a scientific question and as the basis for making policy decisions. The confidence in regional models depends on how well the field data used to develop the model represent the region of interest, how well the environmental model driving variables (e.g., vegetation type, climate, and soils associated with a site used to parameterize ecosystem models) represent the region of interest, and how well regional model predictions agree with observed data for the region. To assess the accuracy of global model forecasts of terrestrial carbon cycling, two Ecosystem Model-Data Intercomparison (EMDI) workshops were held (December 1999 and April 2001). The workshops included 17 biogeochemical, satellite-driven, detailed process, and dynamic vegetation global model types. The approach was to run regional or global versions of the models for sites with net primary productivity (NPP) measurements (i.e., not fine-tuned for specific site conditions) and analyze the model-data differences. Extensive worldwide NPP data were assembled with model driver data, including vegetation, climate, and soils data, to perform the intercomparison. This report describes the compilation of NPP estimates for 2,523 sites and 5,164 0.5{sup o}-grid cells under the Global Primary Production Data Initiative (GPPDI) …

Magnetic islands in free-boundary stellarator equilibria are suppressed using a procedure that iterates the plasma equilibrium equations and, at each iteration, adjusts the coil geometry to cancel resonant fields produced by the plasma. The coils are constrained to satisfy certain measures of engineering acceptability and the plasma is constrained to ensure kink stability. As the iterations continue, the coil geometry and the plasma simultaneously converge to an equilibrium in which the island content is negligible. The method is applied with success to a candidate plasma and coil design for the National Compact Stellarator eXperiment [Physics of Plasma, 7 (2000) 1911].

The IR spectra and normal-mode analysis of the adamantane-like compound [Mn4O6(bpea)4]n+ in two oxidation states, MnIV4 and MnIIIMnIV3, that are relevant to the oxygen-evolving complex of photosystem II are presented. Mn-O vibrational modes are identified with isotopic exchange, 16O->18O, of the mono-(mu)-oxo bridging atoms in the complex. IR spectra of the MnIIIMnIV3 species are obtained by electrochemical reduction of the MnIV4 species using a spectroelectrochemical cell, based on attenuated total reflection [Visser et al. Anal Chem 2001, 73, 4374-4378]. A novel method of subtraction is used to reduce background contributions from solvent and ligand modes, and the difference and double-difference spectra are used in identifying Mn-O bridging modes that are sensitive to oxidation state change. Two strong IR bands are observed for the MnIV4 species at 745 and 707 cm-1 and a weaker band at 510 cm-1. Upon reduction, the MnIIIMnIV3 species exhibits two strong IR bands at 745 and 680 cm-1, and several weaker bands are observed in the 510 - 425 cm-1 range. A normal mode analysis is performed to assign all the relevant bridging modes in the oxidized MnIV4 and reduced MnIIIMnIV3 species. The calculated force constants for the MnIV4 species are = 3.15 mdynAngstrom, = 0.55 …

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

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

The initial objective of this study was to better understand the reasons for the substantial increase in filter DP that was observed after the gasifier recycle loop modifications. Beyond this specific objective, a secondary goal was to develop a meaningful method of evaluating the effect of particle size and other particle properties on dustcake drag and filter DP. As mentioned earlier, the effect of particle size on dustcake drag and filter DP can be a very important consideration in the selection and specification of a precleaner cyclone for use upstream of the hot-gas filter. Installing a cyclone ahead of a hot-gas filter will reduce the transient areal loading of dust to the filter, but the beneficial effect of the reduced areal loading may be offset by an increase in drag associated with a finer particle-size distribution. The overall goal of this study was to better understand these tradeoffs and to ultimately develop a procedure that would be useful in analyzing the performance of hot-gas filters and in sizing new hot-gas filters. In addition to the obvious effects of a cyclone on dust loading and particle size, other indirect effects on particulate properties and flow resistance may occur when the cyclone …

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

Weekly newspaper from Wynnewood, Oklahoma that includes local, state, and national news along with advertising.

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.

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

Coal gasification produces residual particles of coal char, coal ash, and sorbent that are suspended in the fuel gas stream exiting the gasifier. In most cases, these particles (referred to, hereafter, simply as char) must be removed from the stream prior to sending the gas to a turbine, fuel cell, or other downstream device. Currently, the most common approach to cleaning the gas stream at high temperature and pressure is by filtering the particulate with a porous ceramic or metal filter. However, because these dusts frequently have small size distributions, irregular morphology, and high specific surface areas, they can have very high gas flow resistance resulting in hot-gas filter system operating problems. Typical of gasification chars, the hot-gas filter dustcakes produced at the Power Systems Development Facility (PSDF) during recent coal gasification tests have had very high flow resistance (Martin et al, 2002). The filter system has been able to successfully operate, but pressure drops have been high and filter cleaning must occur very frequently. In anticipation of this problem, a study was conducted to investigate ways of reducing dustcake pressure drop. This paper will discuss the efficacy of adding low-flow-resistance particulate matter to the high-flow-resistance char dustcake to reduce …

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

Weekly magazine containing news, information about events, interviews, and articles of interest to the gay and lesbian community in Texas, with advertising.

Weekly magazine containing news, information about events, interviews, and articles of interest to the gay and lesbian community in Texas, with advertising.

Weekly student newspaper published in Hurst, Texas and serving the Tarrant County College District that includes school news and information along with advertising.

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

Tri-weekly student newspaper from Abilene Christian University in Abilene, Texas that includes local, state and campus news along with advertising.

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.

Tri-weekly student newspaper from Abilene Christian University in Abilene, Texas that includes local, state and campus news along with advertising.

Weekly newspaper from Wynnewood, Oklahoma that includes local, state, and national news along with advertising.

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

Weekly newspaper published in Duncanville, Texas that includes local Cedar Hill, state, and national news along with advertising.

Semiweekly newspaper from Brady, Texas that includes local, state, and national news along with advertising.