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The cereal cyst nematode Heterodera avenae can be extracted from soil using several different floatation or elutriation methods. Automated methods are prohibitively expensive for use in small labs and, for optimal efficiency, floatation methods require that the soil be air dried for an extended period. A method which suspends soil particles in a water column above a fluidizing plate was reported as being most efficient with wet and dry soils. Use of the fluidizing column for extracting H. avenae has not been reported in the United States and materials to construct the column using contemporary components have not been described. Objectives of this research were to construct a column with components available in the United States, and to compare numbers of cysts and eggs plus juveniles (from cysts) extracted by the column and three other floatation methods: Fenwick can, flask, and Cobb sieving. From a soil containing recently produced (more dense) cysts, the column extracted at least 18% more cysts and 23% more eggs plus juveniles than the Fenwick and flask methods. The fluidizing column was found to be useful for small laboratories because it is inexpensive ($253 for two columns), easily and quickly constructed by nonprofessional labor, and produces adequately repeatable results. [ABSTRACT FROM AUTHOR]

The National Renewable Energy Laboratory (NREL) is collaborating with both industrial and academic partners to develop technologies to help enable commercialization of biofuels produced from lignocellulosic biomass feedstocks. The focus of this paper is to report how various operating processes, utilized in-house and by collaborators, influence the catalytic activity during conditioning of biomass-derived syngas. Efficient cleaning and conditioning of biomass-derived syngas for use in fuel synthesis continues to be a significant technical barrier to commercialization. Multifunctional, fluidizable catalysts are being developed to reform undesired tars and light hydrocarbons, especially methane, to additional syngas, which can improve utilization of biomass carbon. This approach also eliminates both the need for downstream methane reforming and the production of an aqueous waste stream from tar scrubbing. This work was conducted with NiMgK/AlO catalysts. These catalysts were assessed for methane reforming performance in (i) fixed-bed, bench-scale tests with model syngas simulating that produced by oak gasification, and in pilot-scale, (ii) fluidized tests with actual oak-derived syngas, and (iii) recirculating/regenerating tests using model syngas. Bench-scale tests showed that the catalyst could be completely regenerated over several reforming reaction cycles. Pilot-scale tests using raw syngas showed that the catalyst lost activity from cycle to cycle when it was regenerated, though it was shown that bench-scale regeneration by steam oxidation and H reduction did not cause this deactivation. Characterization by TPR indicates that the loss of a low temperature nickel oxide reduction feature is related to the catalyst deactivation, which is ascribed to nickel being incorporated into a spinel nickel aluminate that is not reduced with the given activation protocol. Results for 100 h time-on-stream using a recirculating/regenerating reactor suggest that this type of process could be employed to keep a high level of steady-state reforming activity, without permanent deactivation of the catalyst. Additionally, the differences in catalyst performance using a simulated and real, biomass-derived syngas stream indicate that there are components present in the real stream that are not adequately modeled in the syngas stream. Heavy tars and polycyclic aromatics are known to be present in real syngas, and the use of benzene and naphthalene as surrogates may be insufficient. In addition, some inorganics found in biomass, which become concentrated in the ash following biomass gasification, may be transported to the reforming reactor where they can interact with catalysts. Therefore, in order to gain more representative results for how a catalyst would perform on an industrially-relevant scale, with real contaminants, appropriate small-scale biomass solids feeders or slip-streams of real process gas should be employed. [ABSTRACT FROM AUTHOR]

Abstract: High-speed video imaging of particle clusters in and above a fluidized bed suggests that clustering is significant for FCC catalyst and polyethylene powders. Based on fluidized bed experiments at varying fines concentration, bed heights and bed internals location, the dominant mechanism for clusters in the freeboard appears to be cluster formation in the bed. Some of these clusters are then subsequently ejected into the freeboard region. Hydrodynamics does not appear to be solely responsible for cluster formation. Cohesive forces such as electrostatics, capillary and van der Waals forces, appear to play a significant role in particle cluster formation. The proposed mechanism suggests that particle shear produces collisional cooling that allows the granular temperature to decay to where these cohesive forces can dominate. The decrease in the granular temperature appears to be dependent on the particle properties and surface morphology. Collisions that only redirect the particle or increase particle rotation, limits this reduction in the granular temperature such that cohesive forces are less of an impact. In the case of risers, where large shear streams are prevalent, these clusters and the corresponding drag forces may result in the formation of larger clusters or streamers. [Copyright &y& Elsevier]

The article discusses the growing demand for polysilicon business in the United States, as of August 2008. The section reports the demand for polysilicon plants in North America in order to meet the growing requirement for solar energy. The author also examines the birth of the polysilicon system of creating renewable energy sources, using the fluidized-bed process. According to the report, the strong demand for solar energy pushes polysilicon manufacturers to add their capacity at an unprecedented rate. Methods or steps that are taken to produce polysilicon are also discussed.

Drilled shaft refers to a deep foundation system where a single large diameter pier is used to replace a whole group of piles. High slump self-compacting concrete is used in drilled shafts due to its high fluidity and less proneness to segregation. The Florida Department of Transportation (FDOT) specifications require that such concrete should have a slump between 7 and 9 in. when placed and should maintain a slump of 4 in. or more throughout the concrete placement time. Furthermore, the mix for the slump loss test should be prepared at a temperature consistent with the highest ambient or initial concrete temperature (whichever is greater) expected during actual concrete placement. It is possible that the temperature of concrete inside the drilled shaft is lower than the ambient or initial concrete temperature due to the presence of ground water. If that is the case, slump loss would be less than the loss determined at the highest ambient or the initial concrete temperature, making the FDOT requirement unrealistic. However, it should be experimentally verified. This experimental study was conducted with the objective to establish profiles of concrete temperature in time from placement to hardening along depth as well as across width of the drilled shaft. Based on the gathered data, it was found that no significant temperature differential existed along the depth and across the width of the drilled shaft during the initial setting of concrete. The temperature of concrete inside the drilled shaft was same as initial concrete temperature before placement at all locations. This finding leads to the conclusion that concrete temperature inside drilled shaft is not affected by ambient temperature and/or the underground temperature conditions. [Copyright &y& Elsevier]

Patterns of deformation within the Upheaval Dome structure, Utah, provide important clues for assessing its possible impact origin. The complex structure of the innermost part of the dome, in particular of the White Rim Sandstone (WRS), indicated almost complete loss of internal coherence during deformation. The WRS displays extreme thickness variations, blind terminations and frequent embranchments at nodular-like points. This, together with discordant contacts to the country rock, shows that WRS builds up a dike network that was emplaced and injected during formation of the central dome. Microstructural analysis reveals that the macroscopically ductile appearance is achieved by distributed cataclastic flow. Beside intergranular fracturing, dislocation pile-ups, dislocation arrays and tangles indicate additional dislocation glide activity in quartz of WRS during deformation. Disseminated brittle fault zone networks postdate the cataclastic flow and represent the final deformation increments during formation of the central uplift. The distributed cataclastic flow in the sandstones was initiated by grain crushing, collapse of pore space, and subsequent intergranular shear. In accordance with experimental data for a similar sandstone (Berea sandstone), it is suggested that a high effective confining pressure, most likely in excess of 250 MPa, was necessary to cause this flow. At shallow crustal levels (maximum possible depth of burial of WRS is 3 km) such a high confining pressure can only be build up dynamically by impact processes. From deformation mechanisms, a shock wave attenuation to magnitudes below the Hugoniot elastic limit of quartz can be deduced and correlates with a burial of the studied sediments of 2–3 km at the time of the impact. [Copyright &y& Elsevier]

Examines volcanic fluidization in the Heart Mountain detachment in Wyoming. Presence of microbreccia containing volcanic glass grains; Source of the volcanic contribution from a fixed feeder pipe; Volcanics in the upper plate; Injection of volcanic gases along the fault.