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Sample records for near-face bed zone

  1. Zone heating for fluidized bed silane pyrolysis

    NASA Technical Reports Server (NTRS)

    Iya, Sridhar K. (Inventor)

    1987-01-01

    An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower reaction zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

  2. Spectral zone selection methodology for pebble bed reactors

    SciTech Connect

    Ramatsemela Mphahlele; Abderrafi M. Ougouag; Kostadin N. Ivanov; Hans D. Gougar

    2011-01-01

    A methodology is developed for determining boundaries of spectral zones for pebble bed reactors. A spectral zone is defined as a region made up of a number of nodes whose characteristics are collectively similar and that are assigned the same few-group diffusion constants. The spectral zones are selected in such a manner that the difference (error) between the reference transport solution and the diffusion code solution takes a minimum value. This is achieved by choosing spectral zones through optimally minimizing this error. The objective function for the optimization algorithm is the total reaction rate error, which is defined as the sum of the leakage, absorption and fission reaction rates errors in each zone. The selection of these spectral zones is such that the core calculation results based on diffusion theory are within an acceptable tolerance as compared to a proper transport reference solution. Through this work, a consistent approach for identifying spectral zones that yield more accurate diffusion results is introduced.

  3. The elastic response of grounding zones over soft beds

    NASA Astrophysics Data System (ADS)

    Sayag, R.; Worster, M. G.

    2011-12-01

    The grounding line at the junction between a grounded sheet and a floating shelf is a free boundary that responds to processes in the ocean, the bed and the ice. Combining observations of the ice-surface elevation with scaling analysis, we show that the response of the ice near grounding lines can be dominated by elastic deformation. We use the theory of elastic sheet-shelf systems on elastic beds (Sayag and Worster, 2011, in press, Control ID 1191878) to relate between satellite observations of the break-in-slope and the Archimidean positions, to the elastic properties of ice and the grounding line position, and give theoretical bounds on these quantities in the limits of stiff and soft beds. Using satellite observations to estimate those bounds and comparing the theoretical predictions with laboratory measurements of the elastic modulus of ice, we find that a better agreement etween theory and observations is achieved assuming a stiff bed at some regions and a softer bed in others. In addition, we demonstrate that the grounding line position can vary substantially with respect to the interval between the break-in-slope and the Archimeadian positions, depending on the softness of the bed. Finally, we suggest an alternative explanation for the wedge structure of the bed near the grounding line reported in observational studies, through the deformation of soft beds under the action of the ice weight and buoyancy.

  4. A Survey of nearby, nearly face-on spiral galaxies

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    2014-09-01

    This is a continuation of a survey of nearby, nearly face-on spiral galaxies. The main purpose is to search for evidence of collisions with small galaxies that show up in X-rays by the generation of hot shocked gas from the collision. Secondary objectives include study of the spatial distribution point sources in the galaxy and to detect evidence for a central massive blackhole.

  5. A Survey of nearby, nearly face-on spiral galaxies

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    2014-09-01

    This is a continuation of a survey of nearby, nearly face-on spiral galaxies. The main purpose is to search for evidence of collisions with small galaxies that show up in X-rays by the generation of hot shocked gas from the collision. Secondary objectives include study of the spatial distribution point sources in the galaxy and to detect evidence for a central massive blackhole. These are alternate targets.

  6. Swash-zone velocity profiles and bed stress on a natural beach

    NASA Astrophysics Data System (ADS)

    Puleo, J. A.; Lanckriet, T.; Wang, P.

    2010-12-01

    The swash zone, where waves wash up and down the beach, is a difficult region of the nearshore to quantify velocity. Water depths in the swash zone can range from zero to over a meter and flows can be turbulent and bubble-laden. Swash flows are often assumed to be depth uniform partially because current meters typically cannot be placed closer than a few centimeters above the bed, although some previous field research has shown flow variability within elevations several centimeters above the bed. The swash-zone boundary layer, where flow momentum is transferred to the bed, must extend below elevations accessible to conventional current meters. Laser Doppler and video-based techniques have shown the shape of this boundary layer over smooth and rough impermeable and mobile granular beds in the laboratory, but to the author’s knowledge, the swash-zone boundary layer below 2-3 cm has never been measured on a natural beach. During August 16-19, 2010 a swash-zone study was conducted at several beaches in west-central Florida in an effort to measure the swash-zone boundary layer and bed shear stress. A new acoustic velocity profiling sensor, the Nortek Vectrino-II, has the capability to measure x, y and z velocity at 1mm increments over 30 bins at the finest setting. During the study 3 Vectrino-II’s were deployed with different profiling ranges in an effort to capture the boundary layer structure. Utilizing the velocity profile, bed stress is estimated using several different techniques including the “law of the wall” approach and nearbed velocity gradients. Preliminary results of the swash-zone boundary layer structure, friction velocity and bed stress as a function of swash phase will be discussed.

  7. The role of bed-parallel slip in the development of complex normal fault zones

    NASA Astrophysics Data System (ADS)

    Delogkos, Efstratios; Childs, Conrad; Manzocchi, Tom; Walsh, John J.; Pavlides, Spyros

    2017-04-01

    Normal faults exposed in Kardia lignite mine, Ptolemais Basin, NW Greece formed at the same time as bed-parallel slip-surfaces, so that while the normal faults grew they were intermittently offset by bed-parallel slip. Following offset by a bed-parallel slip-surface, further fault growth is accommodated by reactivation on one or both of the offset fault segments. Where one fault is reactivated the site of bed-parallel slip is a bypassed asperity. Where both faults are reactivated, they propagate past each other to form a volume between overlapping fault segments that displays many of the characteristics of relay zones, including elevated strains and transfer of displacement between segments. Unlike conventional relay zones, however, these structures contain either a repeated or a missing section of stratigraphy which has a thickness equal to the throw of the fault at the time of the bed-parallel slip event, and the displacement profiles along the relay-bounding fault segments have discrete steps at their intersections with bed-parallel slip-surfaces. With further increase in displacement, the overlapping fault segments connect to form a fault-bound lens. Conventional relay zones form during initial fault propagation, but with coeval bed-parallel slip, relay-like structures can form later in the growth of a fault. Geometrical restoration of cross-sections through selected faults shows that repeated bed-parallel slip events during fault growth can lead to complex internal fault zone structure that masks its origin. Bed-parallel slip, in this case, is attributed to flexural-slip arising from hanging-wall rollover associated with a basin-bounding fault outside the study area.

  8. Stable hydrogen production by methane steam reforming in a two zone fluidized bed reactor: Experimental assessment

    NASA Astrophysics Data System (ADS)

    Pérez-Moreno, L.; Soler, J.; Herguido, J.; Menéndez, M.

    2013-12-01

    The Two Zone Fluidized Bed Reactor concept is proposed for hydrogen production via the steam reforming of methane (SRM) including integrated catalyst regeneration. In order to study the effect of the contact mode, the oxidative SRM has been carried out over a Ni/Al2O3 catalyst using a fixed bed reactor (fBR), a conventional fluidized-bed reactor (FBR) and the proposed two-zone fluidized bed reactor (TZFBR). The technical feasibility of these reactors has been studied experimentally, investigating their performance (CH4 conversion, CO and H2 selectivity, and H2 global yield) and stability under different operating conditions. Coke generation in the process has been verified by several techniques. A stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The viability of the TZFBR for carrying out this process with a valuable global yield to hydrogen is demonstrated.

  9. A preliminary report on a zone containing thick lignite beds, Denver Basin, Colorado

    USGS Publications Warehouse

    Soister, Paul E.

    1973-01-01

    A zone of lignite beds of Paleocene age in the Denver Formation (Upper Cretaceous and Paleocene) lies about 800-1,500 feet above the well-known and extensively mined coal beds of the Laramie Formation (Upper Cretaceous). The zone is a few hundred to as much as 500 feet thick. Where lignite beds lie within 1,000 feet of the surface, this zone underlies an area about 30 miles wide by about 75 miles long, stretching from just northeast of Denver to several miles south of Calhan. Fifteen mines were operated at various periods between 1874 and 1940 and probably produced a total of less than 100,000 tons of lignite, mostly for local use. From 1874 to 1974, several geologists have reported on this lignite zone or the enclosing beds, but no detailed reports have been written except for one by this writer. Drill holes are the main source of geologic data, owing to poor exposure. There are generally about 3 to 6 lignite beds, and they are mostly about 15 or 20 to a few tens of feet apart. Most or all beds typically contain numerous non-coal partings from a fraction of an inch to several inches thick, so that thickness of lignite beds should be stated as gross thickness and as net lignite thickness; net lignite thickness is generally from 70 to 90 percent of gross thickness. Many partings are composed of kaolin, but others are composed of other clay minerals, siltstone, and sandstone. The lignite beds range generally from 1 or 2 to several feet thick, and some are as much as 10-25 feet thick; the thickest known bed has a maximum thickness of 54.5 feet, with a net lignite thickness of 40 feet. Most lignite beds seem to have fair lateral continuity, and at least some beds are several miles in extent. The thickest known lignite bed was traced for at least 18 miles, from northwest to southeast of Watkins. The lignite is brownish-black to black, weathers, checks, and disintegrates rapidly, and even in drill cores from a few hundred feet in depth the lignite is easily broken by

  10. Effect of Local Slope on Bed Load Transport in the Surf Zone

    NASA Astrophysics Data System (ADS)

    Calantoni, J.; Drake, T. G.

    2001-12-01

    Energetics models for sediment transport in the surf zone do not account for gravity-induced transport that is not collinear with fluid motion. These models only allow for a single value of local bed slope to be specified in the cross-shore direction. While in theory, energetics models have predictive capability for both cross-shore and long-shore sediment transport they are typically only used to predict cross-shore transport in practice. A suite of three-dimensional discrete particle computer simulations of bed load transport was performed for a variety of flow conditions and a range of bed slopes (both parallel and perpendicular to the flow) common to the surf zone. In the case where the bed slope is perpendicular to the fluid motion, for example, cross-shore wave-generated oscillatory flow over a bed locally sloping long shore, the long shore component of the bed load transport rate is linearly related to the net cross-shore component for slopes up to 10 degrees. At higher long shore slopes, the long shore transport rate grows nonlinearly with the slope and can exceed the cross-shore rate at slopes approaching the angle of repose. Such transport has important implications for the modeling of smaller scale, three-dimensional bed features (from megaripples to rip channels). Previous modifications to the Bagnold/Bowen/Bailard energetics-based bed load transport formulae can be expanded to include the effects of an arbitrary local bed slope (by allowing for the input of both cross-shore and long shore local slopes) using a vector formulation that can be easily tested with velocity and bathymetry measurements commonly obtained in field experiments. Research supported by the Coastal Dynamics Program of the Office of Naval Research and the National Ocean Partnership Program. >http://www4.ncsu.edu/unity/users/j/joe/public/

  11. Automated spectral zones selection methodology for diffusion theory data preparation for pebble bed reactor analysis

    NASA Astrophysics Data System (ADS)

    Mphahlele, Ramatsemela

    A methodology is developed for the determination of the optimum spectral zones in Pebble Bed Reactors (PBR). In this work a spectral zone is defined as a zone made up of a number of nodes whose characteristics are collectively similar and that are assigned the same few-group diffusion constants. In other words the spectral zones are the regions over which the few-group diffusion parameters are generated. The identification of spectral boundaries is treated as an optimization problem. It is solved by systematically and simultaneously repositioning all zone boundaries to achieve the global minimum error between the reference transport solution (MCNP) and the diffusion code solution (NEM). The objective function for the optimization algorithm is the total reaction rate error, which is defined as the sum of the leakage, absorption and fission reaction rates error in each zone. An iterative determination of group-dependent bucklings is incorporated into the methodology to properly account for spectral effects of neighboring zones. A preferred energy group structure has also been chosen. This optimization approach with the reference transport solution has proved to be accurate and consistent, however the computational effort required to complete the optimization process is significant. Thus a more practical methodology is also developed for the determination of the spectral zones in PBRs. The reactor physics characteristics of the spectral zones have been studied to understand the nature of the spectral zone boundaries. The practical tool involves the use of spectral indices based on few-group diffusion theory whole core calculations. With this methodology, there is no need to first have a reference transport solution. It is shown that the diffusion-theory coarse group fluxes and the effective multiplication factor computed using zones based on the practical index agrees within a narrow tolerance with those of the reference approach. Therefore the "practical" index

  12. Evaluation of center-cut separations applying simulated moving bed chromatography with 8 zones.

    PubMed

    Santos da Silva, Francisco Vitor; Seidel-Morgenstern, Andreas

    2016-07-22

    Different multi-column options to perform continuous chromatographic separations of ternary mixtures have been proposed in order to overcome limitations of batch chromatography. One attractive option is given by simulated moving bed chromatography (SMB) with 8 zones, a process that offers uninterrupted production, and, potentially, improved economy. As in other established ternary separation processes, the separation sequence is crucial for the performance of the process. This problem is addressed here by computing and comparing optimal performances of the two possibilities assuming linear adsorption isotherms. The conclusions are presented in a decision tree which can be used to guide the selection of system configuration and operation.

  13. A Simplified Model for the Behavior of Large Biomass Particles in the Splashing Zone of a Bubbling Bed

    NASA Astrophysics Data System (ADS)

    Brink, Anders; Karlström, Oskar; Hupa, Mikko

    A model for the behavior of biomass particles in the splashing zone of a bubbling bed has been developed. The model is intended for use in CFD studies of bubbling beds, where it provides a way of modeling particle dispersion in the splashing zone. In the model, particles landing on the bed surface are assumed to reenter the splashing zone. Two initial velocities are used for the reentering particles: one represents particles landing on bursting bubbles and one for the emulsion phase. The fraction of the bed consisting of bubbles is calculated using standard expressions from the literature. The re-entering velocity of fuel particles from the bubbles is set such that the flight trajectory reaches the typical height of the splashing zone. The velocity from the emulsion phase is assumed to be of the order of the fluidization velocity. In both cases the initial direction of the trajectory is allowed to take random values. Using these simple assumptions an approximation of the logarithmic material distribution in the splashing zone is achieved.

  14. Delineating a shallow fault zone and dipping bed rock strata using multichannal analysis of surface waves with a land streamer

    USGS Publications Warehouse

    Ivanov, J.; Miller, R.D.; Lacombe, P.; Johnson, C.D.; Lane, J.W.

    2006-01-01

    The multichannel analysis of surface waves (MASW) seismic method was used to delineate a fault zone and gently dipping sedimentary bedrock at a site overlain by several meters of regolith. Seismic data were collected rapidly and inexpensively using a towed 30-channel land streamer and a rubberband-accelerated weight-drop seismic source. Data processed using the MASW method imaged the subsurface to a depth of about 20 m and allowed detection of the overburden, gross bedding features, and fault zone. The fault zone was characterized by a lower shear-wave velocity (Vs) than the competent bedrock, consistent with a large-scale fault, secondary fractures, and in-situ weathering. The MASW 2D Vs section was further interpreted to identify dipping beds consistent with local geologic mapping. Mapping of shallow-fault zones and dipping sedimentary rock substantially extends the applications of the MASW method. ?? 2006 Society of Exploration Geophysicists.

  15. Tiny is mighty: seagrass beds have a large role in the export of organic material in the tropical coastal zone.

    PubMed

    Gillis, Lucy G; Ziegler, Alan D; van Oevelen, Dick; Cathalot, Cecile; Herman, Peter M J; Wolters, Jan W; Bouma, Tjeerd J

    2014-01-01

    Ecosystems in the tropical coastal zone exchange particulate organic matter (POM) with adjacent systems, but differences in this function among ecosystems remain poorly quantified. Seagrass beds are often a relatively small section of this coastal zone, but have a potentially much larger ecological influence than suggested by their surface area. Using stable isotopes as tracers of oceanic, terrestrial, mangrove and seagrass sources, we investigated the origin of particulate organic matter in nine mangrove bays around the island of Phuket (Thailand). We used a linear mixing model based on bulk organic carbon, total nitrogen and δ13C and δ15N and found that oceanic sources dominated suspended particulate organic matter samples along the mangrove-seagrass-ocean gradient. Sediment trap samples showed contributions from four sources oceanic, mangrove forest/terrestrial and seagrass beds where oceanic had the strongest contribution and seagrass beds the smallest. Based on ecosystem area, however, the contribution of suspended particulate organic matter derived from seagrass beds was disproportionally high, relative to the entire area occupied by mangrove forests, the catchment area (terrestrial) and seagrass beds. The contribution from mangrove forests was approximately equal to their surface area, whereas terrestrial contributions to suspended organic matter under contributed compared to their relative catchment area. Interestingly, mangrove forest contribution at 0 m on the transects showed a positive relationship with the exposed frontal width of the mangrove, indicating that mangrove forest exposure to hydrodynamic energy may be a controlling factor in mangrove outwelling. However we found no relationship between seagrass bed contribution and any physical factors, which we measured. Our results indicate that although seagrass beds occupy a relatively small area of the coastal zone, their role in the export of organic matter is disproportional and should be

  16. Tiny Is Mighty: Seagrass Beds Have a Large Role in the Export of Organic Material in the Tropical Coastal Zone

    PubMed Central

    Gillis, Lucy G.; Ziegler, Alan D.; van Oevelen, Dick; Cathalot, Cecile; Herman, Peter M. J.; Wolters, Jan W.; Bouma, Tjeerd J.

    2014-01-01

    Ecosystems in the tropical coastal zone exchange particulate organic matter (POM) with adjacent systems, but differences in this function among ecosystems remain poorly quantified. Seagrass beds are often a relatively small section of this coastal zone, but have a potentially much larger ecological influence than suggested by their surface area. Using stable isotopes as tracers of oceanic, terrestrial, mangrove and seagrass sources, we investigated the origin of particulate organic matter in nine mangrove bays around the island of Phuket (Thailand). We used a linear mixing model based on bulk organic carbon, total nitrogen and δ13C and δ15N and found that oceanic sources dominated suspended particulate organic matter samples along the mangrove-seagrass-ocean gradient. Sediment trap samples showed contributions from four sources oceanic, mangrove forest/terrestrial and seagrass beds where oceanic had the strongest contribution and seagrass beds the smallest. Based on ecosystem area, however, the contribution of suspended particulate organic matter derived from seagrass beds was disproportionally high, relative to the entire area occupied by mangrove forests, the catchment area (terrestrial) and seagrass beds. The contribution from mangrove forests was approximately equal to their surface area, whereas terrestrial contributions to suspended organic matter under contributed compared to their relative catchment area. Interestingly, mangrove forest contribution at 0 m on the transects showed a positive relationship with the exposed frontal width of the mangrove, indicating that mangrove forest exposure to hydrodynamic energy may be a controlling factor in mangrove outwelling. However we found no relationship between seagrass bed contribution and any physical factors, which we measured. Our results indicate that although seagrass beds occupy a relatively small area of the coastal zone, their role in the export of organic matter is disproportional and should be

  17. Vertical structure of near-bed cross-shore flow velocities in the swash zone of a dissipative beach

    NASA Astrophysics Data System (ADS)

    Inch, Kris; Masselink, Gerd; Puleo, Jack A.; Russell, Paul; Conley, Daniel C.

    2015-06-01

    Cross-shore velocity profiles are measured at 0.001 m vertical resolution and at 100 Hz over the lower 0.02-0.07 m of the water column in the mid swash zone on a dissipative, macrotidal beach. Swash motion is predominantly at infragravity frequencies and forced by significant wave heights exceeding 1.5 m and peak wave periods over 15 s. Observations of long duration (> 14 s) swashes during two rising tides are used to quantify the vertical structure of cross-shore flow velocities and estimate corresponding bed shear stress and friction coefficients. Analysis is performed on an individual swash event to an elevation of 0.07 m and an ensemble event made up of 24 individual swash events to an elevation of 0.02 m. Cross-shore velocities exceed 2 m s-1 and are of a similar magnitude during both the uprush and the backwash. Changes in velocity with elevation indicate that the swash zone boundary layer extends to 0.07 m during the strongest flows and is well-represented by the logarithmic model applied to this elevation, except near flow reversal. Maximum bed shear stresses estimated using the logarithmic model are 22 N m-2 and 10 N m-2 for the individual event and ensemble event respectively and mean values are larger during the backwash than the uprush. Mean friction coefficients estimated from equating the logarithmic model and the quadratic drag law are 0.018 and 0.019 for the individual event and ensemble event respectively. Bed shear stress may be underestimated if the logarithmic model is fit to a velocity profile that is only part boundary layer, emphasising the need for high resolution velocity profiles close to the bed for accurate bed shear stress predictions in the swash zone.

  18. Identifying palaeo-ice-stream tributaries on hard beds: Mapping glacial bedforms and erosion zones in NW Scotland

    NASA Astrophysics Data System (ADS)

    Bradwell, Tom

    2013-11-01

    Ice streams are fed by tributaries that can extend deep into the heart of ice sheets. These tributaries are born at onset zones - the abrupt transitions from slow sheet flow to fast streaming flow that often occur at significant topographic steps on hard beds (bedrock-dominated beds). For this reason, tributary onset zones leave only a subtle erosional geomorphic signature in the landscape record that is rarely studied. This paper examines, in detail, the geomorphic signature of ice-sheet flow on a hard bed at the head of a palaeo-ice stream. We use field survey techniques to map glacial bedforms within an ~ 200-km2 area of hard crystalline bedrock in a landscape of ‘areal scour’ around Loch Laxford in NW Scotland. The bedrock bedforms range from plastically moulded (p-forms) and wholly abraded forms, to stoss-lee forms and plucked surfaces all on an outcrop scale (1-100 m). We devise a five-zone classification system to map (in a GIS) the presence, absence, and abundance of glacial erosional forms within 619 (500-m square) grid cells. We go on to use these erosional bedform zones, along with known glaciological relationships to interpret the spatial and altitudinal pattern of palaeo-ice sheet processes and glacier dynamics in this part of NW Scotland. Our interpretation highlights the strong vertical thermal zonation on mountains, and the spatial variations in ice rheology (softness), ice temperature and, by inference, ice velocity in troughs - intimately associated with the onset of ice streaming in tributaries. Consequently, we define the Laxfjord palaeo-ice-stream tributary - a feeder to the Minch palaeo-ice stream in NW Scotland. Finally, we suggest that this new mapping approach could be performed in other deglaciated hard-bed terrain to examine, more widely, the subtle erosional signatures preserved in areas traditionally thought to represent ice sheet ‘areal scour’.

  19. Effects of normobaric hypoxic bed rest on the thermal comfort zone.

    PubMed

    Ciuha, Ursa; Eiken, Ola; Mekjavic, Igor B

    2015-01-01

    Future Lunar and Mars habitats will maintain a hypobaric hypoxic environment to minimise the risk of decompression sickness during the preparation for extra-vehicular activity. This study was part of a larger study investigating the separate and combined effects of inactivity associated with reduced gravity and hypoxia, on the cardiovascular, musculoskeletal, neurohumoural, and thermoregulatory systems. Eleven healthy normothermic young male subjects participated in three trials conducted on separate occasions: (1) Normobaric hypoxic ambulatory confinement, (2) Normobaric hypoxic bedrest and (3) Normobaric normoxic bedrest. Normobaric hypoxia was achieved by reduction of the oxygen fraction in the air (FiO2 = 0.141 ± 0.004) within the facility, while the effects of reduced gravity were simulated by confining the subjects to a horizontal position in bed, with all daily routines performed in this position for 21 days. The present study investigated the effect of the interventions on behavioural temperature regulation. The characteristics of the thermal comfort zone (TCZ) were assessed by a water-perfused suit, with the subjects instructed to regulate the sinusoidally varying temperature of the suit within a range considered as thermally comfortable. Measurements were performed 5 days prior to the intervention (D-5), and on days 10 (D10) and 20 (D20) of the intervention. no statistically significant differences were found in any of the characteristics of the TCZ between the interventions (HAMB, HBR and NBR), or between different measurement days (D-5, D10, D20) within each intervention. rectal temperature remained stable, whereas skin temperature (Tsk) increased during all interventions throughout the one hour trial. no difference in Tsk between D-5, D10 and D20, and between HAMB, HBR and NBR were revealed. subjects perceived the regulated temperature as thermally comfortable, and neutral or warm. we conclude that regulation of thermal comfort is not compromised by

  20. A pseudo three-zone simulated moving bed with solvent gradient for quaternary separations.

    PubMed

    Jiang, Chongwen; Huang, Fengmei; Wei, Feng

    2014-03-21

    In a SMB with solvent gradient, as the eluotropic strength of the liquid in zone II (between the extract-port and feed-port) is higher than that in zone III (between the feed-port and the raffinate-port), the solute can move forward in zone II but backward in zone III to be trapped in the two zones consequently. On this basis, a pseudo-SMB was proposed to separate two medium retained solutes (B1 and B2) from a quaternary mixture by selectively trapping the two solutes. Once the columns in zones II and III are saturated with the target solutes, the solvent dissolving the feed is introduced at the feed-port to remove the least retained solute (A) from the raffinate-port and the most retained solute (C) from the extract-port. The two target components trapped in zones II and III are purified accordingly. At the same time, solute B1 would distribute in the columns of zone III whereas solute B2 spread in the columns of zone II if solute B2 had a stronger retention than solute B1. Thereby, the two medium retained solutes B1 and B2 could be recovered separately from the columns in zones II and III. This scheme was validated by the successful separation of capsaicin (B1) and dihydrocapsaicin (B2) from a crude capsaicinoids.

  1. Correlation chart of Pennsylvanian rocks in Alabama, Tennessee, Kentucky, Virginia, West Virginia, Ohio, Maryland, and Pennsylvania showing approximate position of coal beds, coal zones, and key stratigraphic units

    USGS Publications Warehouse

    Ruppert, Leslie F.; Trippi, Michael H.; Slucher, Ernie R.

    2010-01-01

    This report contains a simplified provisional correlation chart that was compiled from both published and unpublished data in order to fill a need to visualize the currently accepted stratigraphic relations between Appalachian basin formations, coal beds and coal zones, and key stratigraphic units in the northern, central, and southern Appalachian basin coal regions of Alabama, Tennessee, Kentucky, Virginia, West Virginia, Ohio, Maryland, and Pennsylvania. Appalachian basin coal beds and coal zones were deposited in a variety of geologic settings throughout the Lower, Middle, and Upper Pennsylvanian and Pennsylvanian formations were defined on the presence or absence of economic coal beds and coarse-grained sandstones that often are local or regionally discontinuous. The correlation chart illustrates how stratigraphic units (especially coal beds and coal zones) and their boundaries can differ between States and regions.

  2. Revised correlation chart of coal beds, coal zones, and key stratigraphic units in the Pennsylvanian rocks of eastern Kentucky

    USGS Publications Warehouse

    Rice, Charles L.; Hiett, John K.

    1994-01-01

    This report revises Miscellaneous Field Studies Map MF-1188 (Rice and Smith, 1980). Major revisions to the original correlation chart include formal naming of key marine units in Kentucky and replacement of informally named marine units incorrectly projected into Kentucky from adjacent states. Also included in the report is the proper correlation of some regionally recognized coal bed names that have been incorrectly projected into Kentucky, particularly from Ohio and West Virginia. Besides these additions and corrections, minor changes have been made to the correlation chart, all of which are discussed below in detail. The Pennsylvania rocks of the eastern Kentucky coal field underlie an area of about 27,000 square kilometers (see index map). Largely because of the size and stratigra[hic complexity of the area, Huddle and others (1963, p. 31) divided the coal field into six coal-reserve districts. District boundaries utilize state and county line as well as geologic features, drainage areas, and coal producing areas. Their division is followed herein because, in general, each of the districts has a characteristic stratigraphic nomenclature, particularly with regard to coal bed names. The six districts are the Princess, Licking River, Big Sandy, Hazard, Southwestern, and Upper Cumberland River district is divided into the Middlesboro and Harlan subdistricts. The correlation chart lists most of the stratigraphic units of Pennsylvanian age used in eastern Kentucky, and is concerned principally with coal bed names used in publications since about 1950, especially all of the names of coal beds for which resources and reserves have been calculated. Coal constitutes only a small percentage of the total Pennsylvanian-rock sequence, but is present in as many as 26 major coal zones that have been prospected and mined extensively in all parts of the coal field since the early 1900's. Coal names listed in this chart represent coal beds that have been mined commercially or

  3. Multiwavelength study of nearly face-on low surface brightness disk galaxies

    NASA Astrophysics Data System (ADS)

    Gao, Dong; Liang, Yan-Chun; Liu, Shun-Fang; Zhong, Guo-Hu; Chen, Xiao-Yan; Yang, Yan-Bin; Hammer, Francois; Yang, Guo-Chao; Deng, Li-Cai; Hu, Jing-Yao

    2010-12-01

    We study the ages of a large sample (1802) of nearly face-on disk low surface brightness galaxies (LSBGs) using the evolutionary population synthesis (EPS) model PEGASE with an exponentially decreasing star formation rate to fit their multiwavelength spectral energy distributions (SEDs) from far-ultraviolet (FUV) to near-infrared (NIR). The derived ages of LSBGs are 1-5 Gyr for most of the sample no matter if constant or varying dust extinction is adopted, which are similar to most of the previous studies on smaller samples. This means that these LSBGs formed the majority of their stars quite recently. However, a small part of the sample (~2%-3%) has larger ages of 5-8 Gyr, meaning their major star forming process may have occurred earlier. At the same time, a large sample (5886) of high surface brightness galaxies (HSBGs) are selected and studied using the same method for comparisons. The derived ages are 1-5 Gyr for most of the sample (97%) as well. These results probably mean that these LSBGs have not much different star formation histories from their HSBGs counterparts. However, we should notice that the HSBGs are generally about 0.2 Gyr younger, which could mean that the HSBGs may have undergone more recent star forming activities than the LSBGs.

  4. Center-cut separation of intermediately adsorbing target component by 8-zone simulated moving bed chromatography with internal recycle.

    PubMed

    Kiwala, Dawid; Mendrella, Jadwiga; Antos, Dorota; Seidel-Morgenstern, Andreas

    2016-07-01

    An 8-zone simulated moving bed chromatography with internal recycle (8ZSMB-IR) has been designed for center-cut separation, that is, for isolating an intermediately adsorbed component out of a multicomponent mixture. The system consists of two integrated subunits and operates in a fully continuous manner. In the first subunit the feed mixture is split into two fractions containing either a single component or a binary mixture. The binary mixture is recycled through the internal raffinate or extract port into the second subunit, where the target product is isolated. Additionally, the solvent is also recycled internally. For a case study, the separation of a ternary mixture of cycloketones as a model system under weakly non-linear isotherm conditions has been investigated. A few novel configurations of the 8ZSMB-IR unit including the arrangement of the internal recycle of extract, raffinate and solvent streams between two subunits have been examined with respect to various performance indicators for the process realization. The unit performed best with the developed configuration when the internal raffinate stream was recycled and the solvent recycling loop was closed between the last and the first zone of the first subunit. That configuration has further been analyzed experimentally and numerically. On the basis of the results a strategy for determining reliable operating conditions for the 8ZSMB-IR process has been developed. The procedure exploited a model of the process dynamics, which was implemented to refine the isotherm coefficients and to quantify the mixing effect of the liquid stream inside the recycling loops. The upgraded model with the adjusted parameters has been validated based on experimental data and successfully applied for optimizing the operating conditions of the separation.

  5. Effects of Fluctuating River flow on Groundwater/Surface Water Mixing in the Hyporheic Zone of a Regulated, Large Cobble Bed River

    SciTech Connect

    Arntzen, Evan V.; Geist, David R.; Dresel, P. Evan

    2006-10-31

    Physicochemical relationships in the boundary zone between groundwater and surface water (i.e., the hyporheic zone) are controlled by surface water hydrology and the hydrogeologic properties of the riverbed. We studied how sediment permeability and river discharge altered the vertical hydraulic gradient (VHG) and water quality of the hyporheic zone within the Hanford Reach of the Columbia River. The Columbia River at Hanford is a large, cobble-bed river where water level fluctuates up to 2 m daily because of hydropower generation. Concomitant with recording river stage, continuous readings were made of water temperature, specific conductance, dissolved oxygen, and water level of the hyporheic zone. The water level data were used to calculate VHG between the river and hyporheic zone. Sediment permeability was estimated using slug tests conducted in piezometers installed into the river bed. The response of water quality measurements and VHG to surface water fluctuations varied widely among study sites, ranging from no apparent response to co-variance with river discharge. At some sites, a hysteretic relationship between river discharge and VHG was indicated by a time lag in the response of VHG to changes in river stage. The magnitude, rate of change, and hysteresis of the VHG response varied the most at the least permeable location (hydraulic conductivity (K) = 2.9 x 10-4 cms-1), and the least at the most permeable location (K=8.0 x 10-3 cms-1). Our study provides empirical evidence that sediment properties and river discharge both control the water quality of the hyporheic zone. Regulated rivers, like the Columbia River at Hanford, that undergo large, frequent discharge fluctuations represent an ideal environment to study hydrogeologic processes over relatively short time scales (i.e., days to weeks) that would require much longer periods of time to evaluate (i.e., months to years) in un-regulated systems.

  6. Strategy of rearranging the port locations in a three-zone simulated moving bed chromatography for binary separation with linear isotherms.

    PubMed

    Mun, Sungyong

    2012-03-23

    A three-zone simulated moving bed (SMB) chromatographic process for binary separation, which has been developed previously, was reported to have four ports that are located in the order of desorbent, extract, feed, and raffinate. To make a substantial improvement in the performance of such a three-zone SMB process, the strategy of rearranging the port locations was proposed in this study within a linear isotherm region. The core of the proposed strategy is to transfer the location of the extract port from its classical position (i.e., the position between zones I and II) to the zone III outlet. Simultaneously, the feed and raffinate ports are transferred backwards by one zone. Thus, the order of the proposed port locations follows the order of desorbent, feed, raffinate, and extract. The results from both equilibrium-theory analysis and detailed simulation proved that the proposed strategy was highly effective in improving the product purities or throughput of a three-zone SMB process. Furthermore, it was found that such advantage of the proposed strategy became greater as the difference between the adsorption affinities of the feed components was larger.

  7. 75 FR 28554 - Foreign-Trade Zone 50 Long Beach, California, Application for Subzone, Louisville Bedding Company...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... to manufacture household bedding products, including mattress pads and pillows (up to 10 million pillows and 2 million mattress pads annually) for the U.S. market and export. LBC is requesting authority... and higher) cotton, polyester, and synthetic woven fabric and pillow shells (classified under...

  8. Pd-Ag Membrane Coupled to a Two-Zone Fluidized Bed Reactor (TZFBR) for Propane Dehydrogenation on a Pt-Sn/MgAl2O4 Catalyst

    PubMed Central

    Medrano, José-Antonio; Julián, Ignacio; Herguido, Javier; Menéndez, Miguel

    2013-01-01

    Several reactor configurations have been tested for catalytic propane dehydrogenation employing Pt-Sn/MgAl2O4 as a catalyst. Pd-Ag alloy membranes coupled to the multifunctional Two-Zone Fluidized Bed Reactor (TZFBR) provide an improvement in propane conversion by hydrogen removal from the reaction bed through the inorganic membrane in addition to in situ catalyst regeneration. Twofold process intensification is thereby achieved when compared to the use of traditional fluidized bed reactors (FBR), where coke formation and thermodynamic equilibrium represent important process limitations. Experiments were carried out at 500–575 °C and with catalyst mass to molar flow of fed propane ratios between 15.1 and 35.2 g min mmol−1, employing three different reactor configurations: FBR, TZFBR and TZFBR + Membrane (TZFBR + MB). The results in the FBR showed catalyst deactivation, which was faster at high temperatures. In contrast, by employing the TZFBR with the optimum regenerative agent flow (diluted oxygen), the process activity was sustained throughout the time on stream. The TZFBR + MB showed promising results in catalytic propane dehydrogenation, displacing the reaction towards higher propylene production and giving the best results among the different reactor configurations studied. Furthermore, the results obtained in this study were better than those reported on conventional reactors. PMID:24958620

  9. Evidence of the dominance of higher-mode surface waves in the lake-bed zone of the Valley of Mexico

    NASA Astrophysics Data System (ADS)

    Shapiro, N. M.; Singh, S. K.; Almora, D.; Ayala, M.

    2001-12-01

    We compare ground motions recorded at the surface and in boreholes at five different locations of the lake-bed zone of the Valley of Mexico with theoretical dispersion curves and eigenfunctions calculated for the first two modes of Rayleigh and Love waves. We find that (1) the maximum in the horizontal-to-vertical displacement ratio, which occurs at the dominant frequency of the site (0.4Hz), corresponds to the higher mode rather than to the fundamental mode of the Rayleigh waves, (2) borehole records at depths from 0 to 100m show that the normalized vertical displacement does not decrease rapidly below the superficial clay layer, as should be the case for the fundamental mode, but remains ~ 0.8, and (3) the measured phase velocity at a period of about 2.5s (2.0+/-0.5kms-1 ) is too fast for the fundamental mode predicted for the known crustal velocity structure. These observations lead us to conclude that the wavefield in the lake-bed zone in Mexico City is dominated by higher-mode surface waves. This provides a plausible explanation for the long duration of the coda in the lake-bed zone. Although shear wave Q is very small (10-20) in the clay layer, the higher modes of surface waves do not propagate in the superficial clay layer but in the underlying structure where Q -values are likely to be relatively high. Thus, while the clay layer plays the passive role of amplifying the ground motion, its contribution in damping out the motion is insignificant. The results have two important practical implications. (1) The strain estimate from recorded ground velocity differs significantly for the fundamental mode as compared to the higher-mode surface waves. (2) If the ground motion is dominated by the fundamental mode, then knowledge of the superficial layer and the velocity contrast with the underlying structure is sufficient for understanding and modelling of the ground motion. If, however, the higher-mode surface waves dominate, then a detailed knowledge of the deeper

  10. Correlation chart of Pennsylvanian rocks in Alabama, Tennessee, Kentucky, Virginia, West Virginia, Ohio, Maryland, and Pennsylvania showing approximate position of coal beds, coal zones, and key stratigraphic units: Chapter D.2 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    USGS Publications Warehouse

    Ruppert, Leslie F.; Trippi, Michael H.; Slucher, Ernie R.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    Because of the many names used to identify individual coal beds and coal zones in the historic Appalachian basin coal-mining districts, coal bed designations may differ even more than stratigraphic nomenclature. In eastern Kentucky, northwest of the Pine Mountain thrust fault on the Cumberland overthrust sheet, for example, coal beds or coal zones equivalent to the Lower Elkhorn coal zone (within the Pikeville Formation) are identified also as the Eagle coal zone, Pond Creek coal zone, and Blue Gem coal bed (fig. 1). Southeast of the Pine Mountain thrust fault, yet still in Kentucky, equivalent coals in this same interval are known as the Imboden and Rich Mountain. Moreover, this same interval of coal is identified as the Blue Gem coal in Tennessee, the Imboden coal bed or Campbell Creek or Pond Creek coal zones in Virginia, and the Eagle coal zone in West Virginia.

  11. Fusulinoids from the Bashkirian-Moscovian transition beds of the Shahreza region in the Sanandaj-Sirjan Zone, Iran

    NASA Astrophysics Data System (ADS)

    Fassihi, Shirin; Sone, Masatoshi; Hairapetian, Vachik; Esfahani, Fariba Shirezadeh

    2016-12-01

    The presence of the Bashkirian-Moscovian (lower Pennsylvanian) sequence with mixed siliciclastics and fossil-rich carbonates has long been known from the Sanandaj-Sirjan Zone in Iran. However, except for a few studies, its biostratigraphy was not previously investigated in detail. A fusulinoid fauna is recovered from newly measured section, which we named the Asad Abad II section. It is located near the Shahreza town in the Sanandaj-Sirjan Zone. The most important fusulinoids of this assemblage are Aljutovella cf. aljutovica Rauser-Chernosouva, Tikhonovichiella tikhonovichi (Rauser-Chernosouva), and Profusulinella (Depratina) prisca (Deprat); they occur in association with species of Ozawainella, Staffellaeformis, and Pseudostaffella. This fauna overall represents a fauna of the latest Bashkirian-earliest Moscovian transition period in the Sanandaj-Sirjan Zone. This new fusulinoid fauna shares some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. Furthermore, it can be easily compared with those of the Russian Platform, Southern and Northern Urals, and Central Taurides (Turkey). The four species of the current fauna, namely Eostaffella compressa Brazhnikova, E. primitiva (Dutkevich), Pseudostaffella timanica Rauser-Chernosouva, and Profusulinella postpararhombiformis Dzhenchuraeva are reported from Iran for the first time. This study also presents the first occurrence of the genera Aljutovella and Tikhonovichiella in the Sanandaj-Sirjan Zone of Iran.

  12. The Cambric Ditch at the Nevada Test Site as a Long-term Vadose Zone Test Bed

    NASA Astrophysics Data System (ADS)

    Tompson, A. F.; Hunt, J. R.; Hudson, G. B.

    2004-12-01

    Atomic weapons testing at the Nevada Test Site introduced many tracers for quantifying hydrologic transport processes in arid climates. The particular experiment at the Cambric site in Frenchman Flat represents an ongoing 29-year field test that could never be repeated and continues to offer opportunities for vadose zone studies. The Cambric test released the energy yield equivalent of 0.75 kt of TNT when it was detonated 294 m below the land surface and 73 m below the water table in Frenchman Flat in May 1965. Beginning in 1975, groundwater was pumped steadily from a well located 91 m from the detonation point in order to elicit information on radionuclide migration. The pumping well effluent was monitored, discharged to an unlined ditch, and allowed to flow towards a dry lake 1.6 km away. Approximately one third of this flow was lost to infiltration. Over the next 16 years, pumped groundwater was shown to contain tritium, fission products (technetium-99, iodine-129) and activation products (chlorine-36), all of which can be used to trace water flow in the vadose zone. Bromide was also added as an additional tracer into the ditch. Multi-year records exist for water migration in the shallow vadose zone along with temperature profiles. Over the course of the pumping experiment, vegetation developed in and near the ditch, providing an additional pathway for water loss by transpiration and selective radionuclide transport. Significant water has not flowed in the ditch since 1991 and the site remains an ideal analog site for the studying drying in arid climates, the adaptability of vegetation under changing water conditions, and the use of helium-3 as a tracer of soil-atmosphere exchange and vadose zone - groundwater interactions. In addition, there is evidence that tritiated water and chlorine-36 have infiltrated over 200 meters vertically in the vadose zone and have become a source term for groundwater contamination. The Cambric Ditch remains as a field site ideally

  13. Laser powder-bed fusion additive manufacturing: Physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones

    DOE PAGES

    Khairallah, Saad A.; Anderson, Andrew T.; Rubenchik, Alexander; ...

    2016-02-23

    Our study demonstrates the significant effect of the recoil pressure and Marangoni convection in laser powder bed fusion (L-PBF) of 316L stainless steel. A three-dimensional high fidelity powder-scale model reveals how the strong dynamical melt flow generates pore defects, material spattering (sparking), and denudation zones. The melt track is divided into three sections: a topological depression, a transition and a tail region, each being the location of specific physical effects. The inclusion of laser ray-tracing energy deposition in the powder-scale model improves over traditional volumetric energy deposition. It enables partial particle melting, which impacts pore defects in the denudation zone.more » Different pore formation mechanisms are observed at the edge of a scan track, at the melt pool bottom (during collapse of the pool depression), and at the end of the melt track (during laser power ramp down). Finally, we discuss remedies to these undesirable pores are discussed. The results are validated against the experiments and the sensitivity to laser absorptivity.« less

  14. Laser powder-bed fusion additive manufacturing: Physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones

    SciTech Connect

    Khairallah, Saad A.; Anderson, Andrew T.; Rubenchik, Alexander; King, Wayne E.

    2016-02-23

    Our study demonstrates the significant effect of the recoil pressure and Marangoni convection in laser powder bed fusion (L-PBF) of 316L stainless steel. A three-dimensional high fidelity powder-scale model reveals how the strong dynamical melt flow generates pore defects, material spattering (sparking), and denudation zones. The melt track is divided into three sections: a topological depression, a transition and a tail region, each being the location of specific physical effects. The inclusion of laser ray-tracing energy deposition in the powder-scale model improves over traditional volumetric energy deposition. It enables partial particle melting, which impacts pore defects in the denudation zone. Different pore formation mechanisms are observed at the edge of a scan track, at the melt pool bottom (during collapse of the pool depression), and at the end of the melt track (during laser power ramp down). Finally, we discuss remedies to these undesirable pores are discussed. The results are validated against the experiments and the sensitivity to laser absorptivity.

  15. Temperature effects on nitrogen cycling and nitrate removal-production efficiency in bed form-induced hyporheic zones

    NASA Astrophysics Data System (ADS)

    Zheng, Lizhi; Cardenas, M. Bayani; Wang, Lichun

    2016-04-01

    Hyporheic flow in aquatic sediment controls solute and heat transport thereby mediating the fate of nutrients and contaminants, dissolved oxygen, and temperature in the hyporheic zone (HZ). We conducted a series of numerical simulations of hyporheic processes within a dune with different uniform temperatures, coupling turbulent open channel fluid flow, porous fluid flow, and reactive solute transport to study the temperature dependence of nitrogen source/sink functionality and its efficiency. Two cases were considered: a polluted stream and a pristine stream. Sensitivity analysis was performed to investigate the influence of stream water [NO3-]/[NH4+]. The simulations showed that in both cases warmer temperatures resulted in shallower denitrification zones and oxic-anoxic zone boundaries, but the trend of net denitrification rate and nitrate removal or production efficiency of the HZ for these two cases differed. For both cases, at high [NO3-]/[NH4+], the HZ functioned as a NO3- sink with the nitrate removal efficiency increasing with temperature. But at low [NO3-]/[NH4+] for the polluted stream, the HZ is a NO3- sink at low temperature but then switches to a NO3- source at warmer temperatures. For the pristine stream case, the HZ was always a NO3- source, with the NO3- production efficiency increasing monotonically with temperature. In addition, although the interfacial fluid flux expectedly increased with increasing temperature due to decreasing fluid viscosity, the total nitrate flux into the HZ did not follow this trend. This is because when HZ nitrification is high, uniformly elevated [NO3-] lowers dispersive fluxes into the HZ. We found that there are numerous confounding and interacting factors that combined to lead to the final temperature dependence of N transformation reaction rates. Although the temperature effect on the rate constant can be considered as the dominant factor, simply using the Arrhenius equation to predict the reaction rate would lead to

  16. Experimental evaluation of the effect of a modified port-location mode on the performance of a three-zone simulated moving-bed process for the separation of valine and isoleucine.

    PubMed

    Park, Chanhun; Nam, Hee-Geun; Kim, Pung-Ho; Mun, Sungyong

    2014-06-01

    The removal of isoleucine from valine has been a key issue in the stage of valine crystallization, which is the final step in the valine production process in industry. To address this issue, a three-zone simulated moving-bed (SMB) process for the separation of valine and isoleucine has been developed previously. However, the previous process, which was based on a classical port-location mode, had some limitations in throughput and valine product concentration. In this study, a three-zone SMB process based on a modified port-location mode was applied to the separation of valine and isoleucine for the purpose of making a marked improvement in throughput and valine product concentration. Computer simulations and a lab-scale process experiment showed that the modified three-zone SMB for valine separation led to >65% higher throughput and >160% higher valine concentration compared to the previous three-zone SMB for the same separation.

  17. Bed Bugs

    EPA Pesticide Factsheets

    Prevent, identify, and treat bed bug infestations using EPA’s step-by-step guides, based on IPM principles. Find pesticides approved for bed bug control, check out the information clearinghouse, and dispel bed bug myths.

  18. Bed bugs.

    PubMed

    Foulke, Galen T; Anderson, Bryan E

    2014-09-01

    The term bed bug is applied to 2 species of genus Cimex: lectularius describes the common or temperate bed bug, and hemipterus its tropical cousin. Cimex lectularius is aptly named; its genus and species derive from the Latin words for bug and bed, respectively. Though the tiny pest is receiving increased public attention and scrutiny, the bed bug is hardly a new problem.

  19. Enhanced performance of a three-zone simulated moving bed chromatography for separation of succinic acid and lactic acid by simultaneous use of port-location rearrangement and partial-feeding.

    PubMed

    Mun, Sungyong

    2014-07-11

    The performance of a three-zone simulated moving bed (SMB) chromatographic process for separation of succinic acid and lactic acid has been improved to a certain extent in previous researches by applying either a partial-feeding (PF) or a port-location rearrangement (PR) to its operation. To make a further improvement, the strategy of applying both PF and PR simultaneously to the three-zone SMB operation was proposed in this study. The results from both equilibrium-theory analysis and detailed simulation proved that the proposed strategy, which was called PF-PR in this article, had the benefit of a synergy between the individual merits of PF and PR in the three-zone SMB performance. As a consequence, the PF-PR mode could surpass the PF and the PR modes by a wide margin and the classical mode by a dramatic margin in the aspects of separation performance and throughput.

  20. Fluidized bed heating process and apparatus

    NASA Technical Reports Server (NTRS)

    McHale, Edward J. (Inventor)

    1981-01-01

    Capacitive electrical heating of a fluidized bed enables the individual solid particles within the bed to constitute the hottest portion thereof. This effect is achieved by applying an A. C. voltage potential between dielectric coated electrodes, one of which is advantageously the wall of the fluidized bed rejection zone, sufficient to create electrical currents in said particles so as to dissipate heat therein. In the decomposition of silane or halosilanes in a fluidized bed reaction zone, such heating enhances the desired deposition of silicon product on the surface of the seed particles within the fluidized bed and minimizes undesired coating of silicon on the wall of the reaction zone and the homogeneous formation of fine silicon powder within said zone.

  1. Direct Observations of Rapid Basal Melting and Bed Topography in the Grounding Zones of the Dotson and Crosson Ice Shelves, West Antarctica

    NASA Astrophysics Data System (ADS)

    Khazendar, A.; Rignot, E. J.; Schroeder, D. M.; Seroussi, H. L.; Schodlok, M.; Scheuchl, B.; Sutterley, T. C.; Velicogna, I.

    2015-12-01

    Glaciological changes of the Dotson and Crosson ice shelves and their tributary glaciers of Smith, Pope and Kohler are among the most noticeable in the Amundsen Sea Embayment region of West Antarctica. Here, we present sounding radar and laser altimetry observations of two aspects that are indispensable for understanding those changes: basal melting and bedrock topography in the grounding zones. We find that Smith Glacier in particular thinned by a remarkably fast 300-490 m between the years 2002 and 2009. Its grounding line has retreated far enough to be now at 2000 m below sea level in a previously identified trench. All three glacier grounding lines have already retreated down steeper parts of their bedrocks to flatter terrains, plausibly contributing to the reported slowing down in the acceleration of their ice volume discharges. The wider implications of the work emphasize the unprecedented perspectives that direct observation can offer of diverse grounding zone structures and evolution scenarios.

  2. Coupling of solid-phase microextraction continuous bed (monolithic) capillaries with capillary zone electrophoresis for direct analysis of drugs in biological fluids.

    PubMed

    Jarmalaviciene, Reda; Szumski, Michał; Kornysova, Olga; Kłodzińska, Ewa; Westerlund, Douglas; Krawczyk, Stanislas; Mickevicius, Donatas; Buszewski, Bogusław; Maruska, Audrius

    2008-04-01

    Hyperlink robust biocompatible solid-phase microextraction (SPME) devices were prepared using continuous bed (monolithic) restricted-access media (RAM) as the SPME capillary insert. The RAM-based SPME approach was able to simultaneously separate proteins from a biological sample, while directly extracting the active components of caffeine, paracetamol and acetylsalicylic acid from the drug NeoCitramonum. The devices were interfaced with a CZE system and fully automated analysis for sample preconcentration, desorption, separation and quantification of analytes was evaluated. Comparative study of in-line coupled SPME-CZE using RAM and RP capillary inserts was carried out. Using an SPME (RAM) insert, the calculated caffeine, paracetamol and acetylsalicylic acid LODs in a bovine plasma sample were 0.3, 0.8 and 1.9 ng/mL, respectively.

  3. Reversed flow fluidized-bed combustion apparatus

    DOEpatents

    Shang, Jer-Yu; Mei, Joseph S.; Wilson, John S.

    1984-01-01

    The present invention is directed to a fluidized-bed combustion apparatus provided with a U-shaped combustion zone. A cyclone is disposed in the combustion zone for recycling solid particulate material. The combustion zone configuration and the recycling feature provide relatively long residence times and low freeboard heights to maximize combustion of combustible material, reduce nitrogen oxides, and enhance sulfur oxide reduction.

  4. Fluidized bed catalytic coal gasification process

    DOEpatents

    Euker, Jr., Charles A.; Wesselhoft, Robert D.; Dunkleman, John J.; Aquino, Dolores C.; Gouker, Toby R.

    1984-01-01

    Coal or similar carbonaceous solids impregnated with gasification catalyst constituents (16) are oxidized by contact with a gas containing between 2 volume percent and 21 volume percent oxygen at a temperature between 50.degree. C. and 250.degree. C. in an oxidation zone (24) and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone (44) at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

  5. Solar heated fluidized bed gasification system

    NASA Technical Reports Server (NTRS)

    Qader, S. A. (Inventor)

    1981-01-01

    A solar-powered fluidized bed gasification system for gasifying carbonaceous material is presented. The system includes a solar gasifier which is heated by fluidizing gas and steam. Energy to heat the gas and steam is supplied by a high heat capacity refractory honeycomb which surrounds the fluid bed reactor zone. The high heat capacity refractory honeycomb is heated by solar energy focused on the honeycomb by solar concentrator through solar window. The fluid bed reaction zone is also heated directly and uniformly by thermal contact of the high heat capacity ceramic honeycomb with the walls of the fluidized bed reactor. Provisions are also made for recovering and recycling catalysts used in the gasification process. Back-up furnace is provided for start-up procedures and for supplying heat to the fluid bed reaction zone when adequate supplies of solar energy are not available.

  6. Effect of adsorbent particle size on the relative merits of a non-triangular and a triangular separation region in the optimal design of a three-zone simulated moving bed chromatography for binary separation with linear isotherms.

    PubMed

    Mun, Sungyong

    2016-06-24

    The design approaches for a three-zone simulated moving bed (SMB) chromatography with linear isotherms can be classified into two categories, depending on whether the SMB design is based on a classical region (i.e., triangular region of the triangle theory) in the first quadrant (m2, m3) plane or on a non-triangular separation region in the third quadrant (m2, m3) plane. The SMBs based on the classical and the non-triangular design approaches, which are named here as (m(+))_SMB and (m(-))_SMB respectively, are compared in this study using the Pareto solutions from the simultaneous optimization of throughput and desorbent usage under the constraints on product purities and pressure drop. The results showed that the (m(-))_SMB approach led to significantly lower desorbent usage than the (m(+))_SMB approach, which was due to the fact that the flow-rate-ratios from the (m(-))_SMB approach are extremely lower than those from the (m(+))_SMB approach. This factor also enables the (m(-))_SMB to have a significantly lower pressure drop, thereby making its throughput less restricted by a pressure-drop constraint. Due to such advantage of the (m(-))_SMB, it can make a further substantial improvement in throughput by modulating its adsorbent particle size properly. This issue was investigated using a model separation system containing succinic acid and acetic acid. It was confirmed that if the adsorbent particle size corresponding to the boundary between a mass-transfer limiting region and a pressure-drop limiting region is adopted, the (m(-))_SMB can lead to 82% higher throughput and 73% lower desorbent usage than the (m(+))_SMB.

  7. Fluidized bed for production of polycrystalline silicon

    SciTech Connect

    Flagella, R.N.

    1992-08-18

    This patent describes a method for removing silicon powder particles from a reactor that produces polycrystalline silicon by the pyrolysis of a silane containing gas in a fluidized bed reaction zone of silicon seed particles. It comprises introducing the silane containing gas stream into the reaction zone of fluidized silicon seed particles; heterogeneously decomposing the silane containing gas under conditions; collecting the silicon product particles from the collection zone; and removing silicon powder particles from the reactor.

  8. Packed Bed Reactor Experiment

    NASA Video Gallery

    The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

  9. Fluid-bed air-supply system

    DOEpatents

    Atabay, Keramettin

    1979-01-01

    The air-supply system for a fluidized-bed furnace includes two air conduits for the same combustion zone. The conduits feed separate sets of holes in a distributor plate through which fluidizing air flows to reach the bed. During normal operation, only one conduit and set of holes is used, but the second conduit and set of holes is employed during start-up.

  10. Pyrolysis reactor and fluidized bed combustion chamber

    DOEpatents

    Green, Norman W.

    1981-01-06

    A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

  11. Method for in situ gasification of a subterranean coal bed

    DOEpatents

    Shuck, Lowell Z.

    1977-05-31

    The method of the present invention relates to providing controlled directional bores in subterranean earth formations, especially coal beds for facilitating in situ gasification operations. Boreholes penetrating the coal beds are interconnected by laser-drilled bores disposed in various arrays at selected angles to the major permeability direction in the coal bed. These laser-drilled bores are enlarged by fracturing prior to the gasification of the coal bed to facilitate the establishing of combustion zones of selected configurations in the coal bed for maximizing the efficiency of the gasification operation.

  12. 7 CFR 2902.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Bedding, bed linens, and towels. 2902.15 Section 2902... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  13. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  14. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  15. 7 CFR 2902.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Bedding, bed linens, and towels. 2902.15 Section 2902... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  16. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  17. Hybrid fluidized bed combuster

    DOEpatents

    Kantesaria, Prabhudas P.; Matthews, Francis T.

    1982-01-01

    A first atmospheric bubbling fluidized bed furnace is combined with a second turbulent, circulating fluidized bed furnace to produce heat efficiently from crushed solid fuel. The bed of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first bed, and elutriated solids extracted from the flu gases of the first bed. The two-stage combustion of crushed solid fuel provides a system with an efficiency greater than available with use of a single furnace of a fluidized bed.

  18. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, Jer Y.; Cha, Chang Y.; Merriam, Norman W.

    1992-01-01

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyzes the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step.

  19. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, J.Y.; Cha, C.Y.; Merriam, N.W.

    1992-12-15

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyses the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step. 9 figs.

  20. Bed material agglomeration during fluidized bed combustion

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.

    1993-02-01

    The purpose of this project is to determine the physical and chemical reactions which led to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. Survey of industrial-scale fluidized bed combustors is being conducted to determine the occurrence of bed agglomeration and the circumstances under which agglomeration took place. This task should be finished by the end of February. Samples of bed material, agglomerate material, and boiler deposits are being requested from boiler operators as part of the survey. Once received, these sample will be analyzed to determine chemical and mineralogic composition. The bulk chemical determination will be performed using x-ray fluorescence and inductively coupled plasma-optical emission (ICP). Mineralogy will be detected by x-ray diffraction (XRD). Chemical and mineral reactions will be determined by scanning electron microscopy, optical microscopy, and electron microprobe.

  1. Bed Bugs and Schools

    EPA Pesticide Factsheets

    Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

  2. Bed rest during pregnancy

    MedlinePlus

    ... on the inferior vena cava. How Can I Deal with Discomfort from Bed Rest? Bed rest can ... Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the ...

  3. Introduction to Bed Bugs

    EPA Pesticide Factsheets

    The common bed bug (Cimex lectularius) is a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. EPA and other agencies all consider bed bugs a public health pest, but bed bugs are not known to transmit disease.

  4. Making a Bed

    ERIC Educational Resources Information Center

    Wexler, Anthony; Stein, Sherman

    2005-01-01

    The origins of this paper lay in making beds by putting pieces of plywood on a frame: If beds need to be 4 feet 6 inches by 6 feet 3 inches, and plywood comes in 4-foot by 8-foot sheets, how should one cut the plywood to minimize waste (and have stable beds)? The problem is of course generalized.

  5. Fluidized bed coal combustion reactor

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  6. Collaborative Strategy on Bed Bugs

    EPA Pesticide Factsheets

    The Collaborative Strategy on Bed Bugs was developed by the Federal Bed Bug Workgroup to clarify the federal role in bed bug control and highlight ways that government, community, academia and private industry can work together on bed bug issues.

  7. Ash bed level control system for a fixed-bed coal gasifier

    DOEpatents

    Fasching, George E.; Rotunda, John R.

    1984-01-01

    An ash level control system is provided which incorporates an ash level meter to automatically control the ash bed level of a coal gasifier at a selected level. The ash level signal from the ash level meter is updated during each cycle that a bed stirrer travels up and down through the extent of the ash bed level. The ash level signal is derived from temperature measurements made by thermocouples carried by the stirrer as it passes through the ash bed and into the fire zone immediately above the ash bed. The level signal is compared with selected threshold level signal to determine if the ash level is above or below the selected level once each stirrer cycle. A first counter is either incremented or decremented accordingly. The registered count of the first counter is preset in a down counter once each cycle and the preset count is counted down at a selected clock rate. A grate drive is activated to rotate a grate assembly supporting the ash bed for a period equal to the count down period to maintain the selected ash bed level. In order to avoid grate binding, the controller provides a short base operating duration time each stirrer cycle. If the ash bed level drops below a selected low level or exceeds a selected high level, means are provided to notify the operator.

  8. Fluidized bed combustor modeling

    NASA Technical Reports Server (NTRS)

    Horio, M.; Rengarajan, P.; Krishnan, R.; Wen, C. Y.

    1977-01-01

    A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested.

  9. Safety Zones

    EPA Pesticide Factsheets

    These are established primarily to reduce the accidental spread of hazardous substances by workers or equipment from contaminated areas to clean areas. They include the exclusion (hot) zone, contamination reduction (warm) zone, and support (cold) zone.

  10. Cross-channel patterns of bed material transport in a poorly sorted sand-bed channel

    NASA Astrophysics Data System (ADS)

    Haschenburger, J. K.

    2016-11-01

    Understanding of sediment transport comes largely from studies conducted on well-sorted sand-bed and poorly sorted gravel-bed channels. The aim of this study is to evaluate cross-channel patterns of transport rate and grain size in a poorly sorted sand-bed channel. Transport observations were collected from the San Antonio River using a Helley-Smith sampler during flows from 0.02 to 1.1 times bankfull capacity. Resulting transport rates and grain size distributions were pooled to describe eight sections across a channel transect that includes the lower bank and compared to local boundary material. Maximum transport rates are concentrated in the central zone of the streambed regardless of flow level, but gravels and coarse sands are conveyed preferentially on one side of the bed. Grain size distributions change relatively little with flow and approximate the local bed material supply. The size distributions associated with smaller transport rates near the channel margin become finer and more closely approximate the size characteristics of bank material at higher flows. Results extend patterns of differential routing of grain sizes to channel banks and establish the relative fluxes between the bed and bank environments. The small gravel content in poorly sorted sand beds requires further attention because it can contribute to cross-channel variation in sediment fluxes, limit the development of sandy bedforms, and influence the quality of streambed habitat.

  11. Fluidized-bed boilers

    SciTech Connect

    Makansi, J.; Schwieger, B.

    1982-08-01

    This report reviews the current state of atmospheric fluidized-bed combustion. The fundamentals of fluidized-bed combustion and design considerations are first discussed. Tables provide details of manufacturers, worldwide, and of the boilers now installed. Eight plants in various countries and burning a variety of fuels, are described more fully.

  12. Fluidized bed calciner apparatus

    DOEpatents

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  13. Bed Bugs FAQs

    MedlinePlus

    ... allow them to fit into the smallest of spaces and stay there for long periods of time, even without a blood meal. Bed bugs are usually transported from place to place as people travel. The bed bugs travel in the seams and ...

  14. Fluidized bed gasification of extracted coal

    DOEpatents

    Aquino, D.C.; DaPrato, P.L.; Gouker, T.R.; Knoer, P.

    1984-07-06

    Coal or similar carbonaceous solids are extracted by contacting the solids in an extraction zone with an aqueous solution having a pH above 12.0 at a temperature between 65/sup 0/C and 110/sup 0/C for a period of time sufficient to remove bitumens from the coal into said aqueous solution, and the extracted solids are then gasified at an elevated pressure and temperature in a fluidized bed gasification zone (60) wherein the density of the fluidized bed is maintained at a value above 160 kg/m/sup 3/. In a preferred embodiment of the invention, water is removed from the aqueous solution in order to redeposit the extracted bitumens onto the solids prior to the gasification step. 2 figs., 1 tab.

  15. Turning patients over in bed

    MedlinePlus

    Roll patients in bed ... following steps should be followed: Explain to the patient what you are planning to do so the ... Stand on the side of the bed the patient will be turning towards and lower the bed ...

  16. Influence of the bank vegetation on the river bed variations

    NASA Astrophysics Data System (ADS)

    Ruei Ke, Bo; Chan, Hsun-Chuan; Chen, You-Cheng

    2014-05-01

    In the natural rivers, woody vegetation commonly grows along the riverbank. When flood flows run through the woody vegetation zones, the stream processes are markedly affected. This study experimentally discusses the characteristics of flow fields and the changes of river bedform while water flows through woody vegetation zones. The experiments were produced in a flume with 20m long, 1m wide, and a fixed slope of 0.001. The woody vegetation was set in 10 square centimeters at one side of the flume. Experimental vegetation was simulated by the steel columns due to the stem of emergent woody vegetation near bed is rigid. The experimental flow was steady and flow velocity was adopted to near the critical flow for the initiation of sediment motion. Uniform sand with a median size of 0.88 mm was used as the bed sediment. The three dimensional flow fields of time-averaged velocity distributions and turbulent characteristics were measured by an Acoustic Doppler Velocimeter(ADV). The bed morphology of equilibrium scour condition was measured by a Laser Distance Meter. The interactions between water flows and river bed with vegetation ware investigated by observing the scour and deposition processes around the vegetation zone. In addition, the flow fields at flat bed and equilibrium scour conditions are measured separately. Furthermore, the influence of vegetation density on the flow and bedform was investigated by using the present experiment. When the flows passed through the vegetation zones, the approaching flow was retarded by the vegetation zone along the vegetation-bank side and accelerated in the main channel. The flow velocities also reduced downstream of the vegetation zones and the water depths dropped significantly in the streamwise direction. It was observed that the levels of the sediment deposition decreased at downstream of the vegetation zones as the vegetation density increased. Near the vegetation zone, the size of the scour hole increased as the

  17. Modeling hyporheic zone processes

    USGS Publications Warehouse

    Runkel, Robert L.; McKnight, Diane M.; Rajaram, Harihar

    2003-01-01

    Stream biogeochemistry is influenced by the physical and chemical processes that occur in the surrounding watershed. These processes include the mass loading of solutes from terrestrial and atmospheric sources, the physical transport of solutes within the watershed, and the transformation of solutes due to biogeochemical reactions. Research over the last two decades has identified the hyporheic zone as an important part of the stream system in which these processes occur. The hyporheic zone may be loosely defined as the porous areas of the stream bed and stream bank in which stream water mixes with shallow groundwater. Exchange of water and solutes between the stream proper and the hyporheic zone has many biogeochemical implications, due to differences in the chemical composition of surface and groundwater. For example, surface waters are typically oxidized environments with relatively high dissolved oxygen concentrations. In contrast, reducing conditions are often present in groundwater systems leading to low dissolved oxygen concentrations. Further, microbial oxidation of organic materials in groundwater leads to supersaturated concentrations of dissolved carbon dioxide relative to the atmosphere. Differences in surface and groundwater pH and temperature are also common. The hyporheic zone is therefore a mixing zone in which there are gradients in the concentrations of dissolved gasses, the concentrations of oxidized and reduced species, pH, and temperature. These gradients lead to biogeochemical reactions that ultimately affect stream water quality. Due to the complexity of these natural systems, modeling techniques are frequently employed to quantify process dynamics.

  18. Bed Bug Information Clearinghouse

    EPA Pesticide Factsheets

    Its purpose is to help states, communities, and consumers in efforts to prevent and control bed bug infestations. Currently includes only reviewed material from federal/state/local government agencies, extension services, and universities.

  19. Bed Bug Tips

    EPA Pesticide Factsheets

    How to deal with bed bugs in one printable page. Ten tips include ensuring correct insect identification, reducing clutter, understand integrated pest management, using mattress and box spring encasements, and heat treatment.

  20. Tapered bed bioreactor

    DOEpatents

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  1. Particle fuel bed tests

    SciTech Connect

    Horn, F.L.; Powell, J.R.; Savino, J.M.

    1985-01-01

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H/sub 2/ for 12 hours with no visible reaction or weight loss.

  2. Moving-bed sorbents

    SciTech Connect

    Ayala, R.E.; Gupta, R.P.; Chuck, T.

    1995-12-01

    The objective of this program is to develop mixed-metal oxide sorbent formulations that are suitable for moving-bed, high-temperature, desulfurization of coal gas. Work continues on zinc titanates formulations and Z-sorb III sorbent.

  3. Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    NASA Technical Reports Server (NTRS)

    Moran, Robert P.

    2013-01-01

    A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

  4. Simulated moving bed system for CO.sub.2 separation, and method of same

    DOEpatents

    Elliott, Jeannine Elizabeth; Copeland, Robert James; Lind, Jeff; Leta, Daniel P.; McCall, Patrick P.

    2016-09-20

    A system and method for separating and/or purification of CO.sub.2 gas from a CO.sub.2 feed stream is described. The system and method include a plurality of fixed sorbent beds, adsorption zones and desorption zones, where the sorbent beds are connected via valve and lines to create a simulated moving bed system, where the sorbent beds move from one adsorption position to another adsorption position, and then into one regeneration position to another regeneration position, and optionally back to an adsorption position. The system and method operate by concentration swing adsorption/desorption and by adsorptive/desorptive displacement.

  5. Test Bed For Telerobots

    NASA Technical Reports Server (NTRS)

    Matijevic, Jacob R.; Zimmerman, Wayne F.; Dolinsky, Shlomo

    1990-01-01

    Assembly of electromechanical and electronic equipment (including computers) constitutes test bed for development of advanced robotic systems for remote manipulation. Combines features not found in commercial systems. Its architecture allows easy growth in complexity and level of automation. System national resource for validation of new telerobotic technology. Intended primarily for robots used in outer space, test bed adapted to development of advanced terrestrial telerobotic systems for handling radioactive materials, dangerous chemicals, and explosives.

  6. Bed exit alarms.

    PubMed

    2004-09-01

    Bed-exit alarms alert caregivers that a patient who should not get out of bed unassisted is doing so. These alarms can help reduce the likelihood of falls and can promote speedy assistance to patients who have already fallen. But as we described in our May 2004 Guidance Article on bed-exit alarms, they don't themselves prevent falls. They are only effective if used as part of an overall fall-prevention program and with a clear understanding of their limitations. This Evaluation examines the effectiveness of 16 bed-exit alarms from seven suppliers. Our ratings focus primarily on each product's reliability in detecting bed-exit events and alerting caregivers, its ability to minimize nuisance alarms (alarms that sound even though the patient isn't leaving the bed or that sound while a caregiver is helping the patient to leave the bed), and its resistance to deliberate or inadvertent tampering. Twelve of the products use pressure-sensor-activated alarms (mainly sensor pads placed on or under the mattress); three use a cord that can attach to the patient's garment, alarming if the cord is pulled loose from the control unit; and one is a position-sensitive alarm attached to a leg cuff. All the products reliably detect attempted or successful bed exits. But they vary greatly in how effectively they alert staff, minimize nuisance alarms, and resist tampering. Ease of use and battery performance also vary for many units. Of the pressure-sensor units, three are rated Preferred. Those units meet most of our criteria and have no significant disadvantages. Five of the other pressure-sensor products are Acceptable, and the remaining four are Not Recommended. All three cord-activated alarms are rated Acceptable, as is the patient-worn alarm.

  7. Bed rest and immunity

    NASA Astrophysics Data System (ADS)

    Sonnenfeld, Gerald; Aviles, Hernan; Butel, Janet S.; Shearer, William T.; Niesel, David; Pandya, Utpal; Allen, Christopher; Ochs, Hans D.; Blancher, Antoine; Abbal, Michel

    2007-02-01

    Space flight has been shown to result in altered immune responses. The current study was designed to investigate this possibility by using the bed rest model of some space flight conditions. A large number of women are included as subjects in the study. The hypothesis being tested is: 60 days head-down tilt bed rest of humans will affect the immune system and resistance to infection. Blood, urine and saliva samples will be obtained from bed rest subjects prior to, at intervals during, and after completion of 60 days of head-down tilt bed rest. Leukocyte blastogenesis, cytokine production and virus reactivation will be assessed. The ability of the subjects to respond appropriately to immunization with the neoantigen bacteriophage φX-174 will also be determined. Bed rest is being carried out at MEDES, Toulouse France, and the University of Texas Medical Branch, Galveston, TX. The studies to be carried out in France will also allow assessment of the effects of muscle/bone exercise and nutritional countermeasures on the immune system in addition to the effects of bed rest.

  8. Pebble Bed Reactor Dust Production Model

    SciTech Connect

    Abderrafi M. Ougouag; Joshua J. Cogliati

    2008-09-01

    The operation of pebble bed reactors, including fuel circulation, can generate graphite dust, which in turn could be a concern for internal components; and to the near field in the remote event of a break in the coolant circuits. The design of the reactor system must, therefore, take the dust into account and the operation must include contingencies for dust removal and for mitigation of potential releases. Such planning requires a proper assessment of the dust inventory. This paper presents a predictive model of dust generation in an operating pebble bed with recirculating fuel. In this preliminary work the production model is based on the use of the assumption of proportionality between the dust production and the normal force and distance traveled. The model developed in this work uses the slip distances and the inter-pebble forces computed by the authors’ PEBBLES. The code, based on the discrete element method, simulates the relevant static and kinetic friction interactions between the pebbles as well as the recirculation of the pebbles through the reactor vessel. The interaction between pebbles and walls of the reactor vat is treated using the same approach. The amount of dust produced is proportional to the wear coefficient for adhesive wear (taken from literature) and to the slip volume, the product of the contact area and the slip distance. The paper will compare the predicted volume with the measured production rates. The simulation tallies the dust production based on the location of creation. Two peak production zones from intra pebble forces are predicted within the bed. The first zone is located near the pebble inlet chute due to the speed of the dropping pebbles. The second peak zone occurs lower in the reactor with increased pebble contact force due to the weight of supported pebbles. This paper presents the first use of a Discrete Element Method simulation of pebble bed dust production.

  9. Control of bed height in a fluidized bed gasification system

    DOEpatents

    Mehta, Gautam I.; Rogers, Lynn M.

    1983-12-20

    In a fluidized bed apparatus a method for controlling the height of the fdized bed, taking into account variations in the density of the bed. The method comprises taking simultaneous differential pressure measurements at different vertical elevations within the vessel, averaging the differential pressures, determining an average fluidized bed density, then periodically calculating a weighting factor. The weighting factor is used in the determination of the actual bed height which is used in controlling the fluidizing means.

  10. Coal-feeding mechanism for a fluidized bed combustion chamber

    DOEpatents

    Gall, Robert L.

    1981-01-01

    The present invention is directed to a fuel-feeding mechanism for a fluidized bed combustor. In accordance with the present invention a perforated conveyor belt is utilized in place of the fixed grid normally disposed at the lower end of the fluidized bed combustion zone. The conveyor belt is fed with fuel, e.g. coal, at one end thereof so that the air passing through the perforations dislodges the coal from the belt and feeds the coal into the fluidized zone in a substantially uniform manner.

  11. Fluidized-bed catalytic coal-gasification process. [US patent; pretreatment to minimize agglomeration

    DOEpatents

    Euker, C.A. Jr.; Wesselhoft, R.D.; Dunkleman, J.J.; Aquino, D.C.; Gouker, T.R.

    1981-09-14

    Coal or similar carbonaceous solids impregnated with gasification catalyst constituents are oxidized by contact with a gas containing between 2 vol % and 21 vol % oxygen at a temperature between 50 and 250/sup 0/C in an oxidation zone and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

  12. Temporal Hyporheic Zone Response to Water Table Fluctuations.

    PubMed

    Malzone, Jonathan M; Anseeuw, Sierra K; Lowry, Christopher S; Allen-King, Richelle

    2016-03-01

    Expansion and contraction of the hyporheic zone due to temporal hydrologic changes between stream and riparian aquifer influence the biogeochemical cycling capacity of streams. Theoretical studies have quantified the control of groundwater discharge on the depth of the hyporheic zone; however, observations of temporal groundwater controls are limited. In this study, we develop the concept of groundwater-dominated differential hyporheic zone expansion to explain the temporal control of groundwater discharge on the hyporheic zone in a third-order stream reach flowing through glacially derived terrain typical of the Great Lakes region. We define groundwater-dominated differential expansion of the hyporheic zone as: differing rates and magnitudes of hyporheic zone expansion in response to seasonal vs. storm-related water table fluctuation. Specific conductance and vertical hydraulic gradient measurements were used to map changes in the hyporheic zone during seasonal water table decline and storm events. Planar and riffle beds were monitored in order to distinguish the cause of increasing hyporheic zone depth. Planar bed seasonal expansion of the hyporheic zone was of a greater magnitude and longer in duration (weeks to months) than storm event expansion (hours to days). In contrast, the hyporheic zone beneath the riffle bed exhibited minimal expansion in response to seasonal groundwater decline compared to storm related expansion. Results indicated that fluctuation in the riparian water table controlled seasonal expansion of the hyporheic zone along the planar bed. This groundwater induced hyporheic zone expansion could increase the potential for biogeochemical cycling and natural attenuation.

  13. EPA-Registered Bed Bug Products

    MedlinePlus

    ... Pest Bed Bugs EPA Registered Bed Bug Products EPA-Registered Bed Bug Products Resources Bed Bug Main ... Bugs Tips Joint Statement on Bed Bug Control EPA has developed a search tool that can help ...

  14. Cross hospital bed management system.

    PubMed

    Abedian, S; Kazemi, H; Riazi, H; Bitaraf, E

    2014-01-01

    The lack of adequate numbers of hospital beds to accommodate the injured is a main problem in public hospitals. For control of occupancy of bed, we design a dynamic system that announces status of bed when it change with admission or discharge of a patient. This system provide a wide network in country for bed management, especially for ICU and CCU beds that help us to distribute injured patient in the hospitals.

  15. Treatment bed microbiological control

    NASA Technical Reports Server (NTRS)

    Janauer, Gilbert E.; Fitzpatrick, Timothy W.; Kril, Michael B.; Wilber, Georgia A.; Sauer, Richard L.

    1987-01-01

    The effects of microbial fouling on treatment bed (TB) performance are being studied. Fouling of activated carbon (AC) and ion exchange resins (IEX) by live and devitalized bacteria can cause decreased capacity for selected sorbates with AC and IEX TB. More data are needed on organic species removal in the trace region of solute sorption isotherms. TB colonization was prevented by nonclassical chemical disinfectant compositions (quaternary ammonium resins) applied in suitable configurations. Recently, the protection of carbon beds via direct disinfectant impregnation has shown promise. Effects (of impregnation) upon bed sorption/removal characteristics are to be studied with representative contaminants. The potential need to remove solutes added or produced during water disinfection and/or TB microbiological control must be investigated.

  16. Fluidized bed coal desulfurization

    NASA Technical Reports Server (NTRS)

    Ravindram, M.

    1983-01-01

    Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized bed reactor. Chemical pretreatment and posttreatment of coals were tried as a means of enhancing desulfurization. Sequential chlorination and dechlorination cum hydrodesulfurization under modest conditions relative to the water slurry process were found to result in substantial sulfur reductions of about 80%. Sulfur forms as well as proximate and ultimate analyses of the processed coals are included. These studies indicate that a fluidized bed reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.

  17. Staged fluidized bed

    DOEpatents

    Mallon, R.G.

    1983-05-13

    The invention relates to oil shale retorting and more particularly to staged fluidized bed oil shale retorting. Method and apparatus are disclosed for narrowing the distribution of residence times of any size particle and equalizing the residence times of large and small particles in fluidized beds. Particles are moved up one fluidized column and down a second fluidized column with the relative heights selected to equalize residence times of large and small particles. Additional pairs of columns are staged to narrow the distribution of residence times and provide complete processing of the material.

  18. Studies in a moving bed pressure gasifier

    SciTech Connect

    Krishnudu, T.; Madhusudhan, B.; Reddy, S.N.; Sastry, V.S.R.; Rao, K.S.; Vaidyeswaran, R.

    1989-04-01

    Sequential layer samples were collected from a moving bed pressure gasification pilot plant operating at 2.0 MPa after it was quenched by cutting off the supply of oxygen and steam, and the samples were then analyzed. The studies were made with two low-rank coals. Based on the proximate and ultimate analyses and Gray-King assay, three zones - fast devolatilization, slow devolatilization with gasification, and gasification - could be indicated in the gasifier. From a correlation obtained earlier between volatile matter content in the char and the temperature of low-temperature carbonization in a Lurgi Spuelgas type of reactor, the temperature profile in the gasifier was predicted using the volatile matter content in the sequential layer samples. About two-thirds of the total fuel bed height of 3500 mm was for fast and slow devolatilizations and the rest for gasification.

  19. Acoustic bed velocity and bed load dynamics in a large sand bed river

    USGS Publications Warehouse

    Gaeuman, D.; Jacobson, R.B.

    2006-01-01

    Development of a practical technology for rapid quantification of bed load transport in large rivers would represent a revolutionary advance for sediment monitoring and the investigation of fluvial dynamics. Measurement of bed load motion with acoustic Doppler current profiles (ADCPs) has emerged as a promising approach for evaluating bed load transport. However, a better understanding of how ADCP data relate to conditions near the stream bed is necessary to make the method practical for quantitative applications. In this paper, we discuss the response of ADCP bed velocity measurements, defined as the near-bed sediment velocity detected by the instrument's bottom-tracking feature, to changing sediment-transporting conditions in the lower Missouri River. Bed velocity represents a weighted average of backscatter from moving bed load particles and spectral reflections from the immobile bed. The ratio of bed velocity to mean bed load particle velocity depends on the concentration of the particles moving in the bed load layer, the bed load layer thickness, and the backscatter strength from a unit area of moving particles relative to the echo strength from a unit area of unobstructed bed. A model based on existing bed load transport theory predicted measured bed velocities from hydraulic and grain size measurements with reasonable success. Bed velocities become more variable and increase more rapidly with shear stress when the transport stage, defined as the ratio of skin friction to the critical shear stress for particle entrainment, exceeds a threshold of about 17. This transition in bed velocity response appears to be associated with the appearance of longer, flatter bed forms at high transport stages.

  20. Distributor for multistage fluidized beds

    SciTech Connect

    Wormser, A.

    1992-06-16

    This patent describes a multibed fluidized bed system. It comprises a fluidized bed vessel having a casing surrounding a first distributor and a second distributor downstream from the first distributor; a first bed material placed on the first distributor and a second bed material placed on the second distributor; each of the bed materials having an angle of repose; and wherein the angle formed by the substantially straight elongated tubular passages and the upper surface is less than the angle of repose of the second bed material.

  1. Fluid bed material transfer method

    DOEpatents

    Pinske, Jr., Edward E.

    1994-01-01

    A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.

  2. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, A.G.; Patel, J.G.

    1987-05-12

    An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

  3. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1987-05-12

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

  4. Palynological studies of Middle Pennsylvanian coal beds of the proposed Pennsylvania System stratotype in West Virginia

    SciTech Connect

    Kosanke, R.M.

    1988-01-01

    One hundred and ninety-one segment samples from 27 coal beds and adjacent strata occurring in the Kanawha Formation and Charleston Sandstone have been collected and examined in detail. More than 25,000 palynomorphs have been counted in order to establish a standard for the stratotype. Palynomorph abundance, assemblages, range zones, and correlations are documented. Paleoecology, as evidenced by succession of salynomorphs within coal beds and extinctions between coal beds, is reported.

  5. Virtual Test Bed

    DTIC Science & Technology

    2016-06-07

    project is to develop a benchmark system for evaluating models for predicting the characteristics of ocean wind waves. SCIENTIFIC OBJECTIVES A...to be assembled within the virtual test bed. Wind fields for running these tests will be obtained from Oceanweather, Inc. from a separate ONR

  6. Bed Bug Myths

    EPA Pesticide Factsheets

    Learn the truth about bed bugs, such as how easy they are to see with the naked eye, their preferred habitat, whether they transmit diseases, their public health effects, and whether pesticides are the best way to deal with an infestation.

  7. MULTISTAGE FLUIDIZED BED REACTOR

    DOEpatents

    Jonke, A.A.; Graae, J.E.A.; Levitz, N.M.

    1959-11-01

    A multistage fluidized bed reactor is described in which each of a number of stages is arranged with respect to an associated baffle so that a fluidizing gas flows upward and a granular solid downward through the stages and baffles, whereas the granular solid stopsflowing downward when the flow of fluidizing gas is shut off.

  8. Coal hydrogenation and deashing in ebullated bed catalytic reactor

    DOEpatents

    Huibers, Derk T. A.; Johanson, Edwin S.

    1983-01-01

    An improved process for hydrogenation of coal containing ash with agglomeration and removal of ash from an ebullated bed catalytic reactor to produce deashed hydrocarbon liquid and gas products. In the process, a flowable coal-oil slurry is reacted with hydrogen in an ebullated catalyst bed reaction zone at elevated temperature and pressure conditions. The upward velocity and viscosity of the reactor liquid are controlled so that a substantial portion of the ash released from the coal is agglomerated to form larger particles in the upper portion of the reactor above the catalyst bed, from which the agglomerated ash is separately withdrawn along with adhering reaction zone liquid. The resulting hydrogenated hydrocarbon effluent material product is phase separated to remove vapor fractions, after which any ash remaining in the liquid fraction can be removed to produce substantially ash-free coal-derived liquid products.

  9. Bed Bug Clearinghouse by Topic

    EPA Pesticide Factsheets

    This information is intended to help states, communities, and consumers prevent and control bed bug infestations. Topics include bed bug biology and behavior, detection and monitoring, non-chemical techniques such as heat treatment, and pesticides.

  10. Debris-bed friction of hard-bedded glaciers

    NASA Astrophysics Data System (ADS)

    Cohen, D.; Iverson, N. R.; Hooyer, T. S.; Fischer, U. H.; Jackson, M.; Moore, P. L.

    2005-06-01

    Field measurements of debris-bed friction on a smooth rock tablet at the bed of Engabreen, a hard-bedded, temperate glacier in northern Norway, indicated that basal ice containing 10% debris by volume exerted local shear traction of up to 500 kPa. The corresponding bulk friction coefficient between the dirty basal ice and the tablet was between 0.05 and 0.08. A model of friction in which nonrotating spherical rock particles are held in frictional contact with the bed by bed-normal ice flow can account for these measurements if the power law exponent for ice flowing past large clasts is 1. A small exponent (n < 2) is likely because stresses in ice are small and flow is transient. Numerical calculations of the bed-normal drag force on a sphere in contact with a flat bed using n = 1 show that this force can reach values several hundred times that on a sphere isolated from the bed, thus drastically increasing frictional resistance. Various estimates of basal friction are obtained from this model. For example, the shear traction at the bed of a glacier sliding at 20 m a-1 with a geothermally induced melt rate of 0.006 m a-1 and an effective pressure of 300 kPa can exceed 100 kPa. Debris-bed friction can therefore be a major component of sliding resistance, contradicting the common assumption that debris-bed friction is negligible.

  11. Debris-Bed Friction of Hard-Bedded Glaciers

    NASA Astrophysics Data System (ADS)

    Cohen, D.; Iverson, N. R.; Hooyer, T. S.; Fischer, U. H.; Jackson, M.; Moore, P. L.

    2004-12-01

    Field measurements of debris-bed friction on a smooth rock tablet at the bed of Engabreen, a hard-bedded, temperate glacier in northern Norway, indicated that basal ice containing 10% debris by volume exerted local shear traction of up to 500~kPa. The corresponding bulk friction coefficient between the dirty basal ice and the tablet was between 0.05 and 0.08. A model of friction in which non-rotating spherical rock particles are held in frictional contact with the bed by bed-normal ice flow can account for these measurements if ice is Newtonian. Numerical calculations of the bed-normal drag force on a sphere in contact with a flat bed show that this force can reach values several hundred times that on a sphere isolated from the bed, thus drastically increasing frictional resistance. Various estimates of basal friction are obtained from this model. For example, the shear traction at the bed of a 200~m thick glacier sliding at 20~m a-1 with a geothermally induced melt rate of 0.006~m a-1 can exceed 100~kPa. Debris-bed friction can, therefore, be a major component of sliding resistance, contradicting the common assumption that debris-bed friction is negligible.

  12. Fluidized-bed combustion

    SciTech Connect

    Botros, P E

    1990-04-01

    This report describes the activities of the Morgantown Energy Technology Center's research and development program in fluidized-bed combustion from October 1, 1987, to September 30, 1989. The Department of Energy program involves atmospheric and pressurized systems. Demonstrations of industrial-scale atmospheric systems are being completed, and smaller boilers are being explored. These systems include vortex, multi-solid, spouted, dual-sided, air-cooled, pulsed, and waste-fired fluidized-beds. Combustion of low-rank coal, components, and erosion are being studied. In pressurized combustion, first-generation, combined-cycle power plants are being tested, and second-generation, advanced-cycle systems are being designed and cost evaluated. Research in coal devolatilization, metal wastage, tube corrosion, and fluidization also supports this area. 52 refs., 24 figs., 3 tabs.

  13. Fluidized-bed boilers

    SciTech Connect

    Makansi, J.; Schwieger, B.

    1982-08-01

    Discusses atmospheric fluidized-bed (AFB) boilers with regard to designs available, manufacturers involved, and operating experience. Proven fuel flexibility and satisfactory SO/sub 2/ control without scrubbers make AFB boilers a viable option for industrial steam generation worldwide. Technical concepts on which AFB application is based are a departure from the more familiar methods of burning solid fuels. Behind US thrust for AFB development is the need to burn coal within pollution regulations.

  14. Combustion in fluidized beds

    SciTech Connect

    Dry, F.J.; La Nauze, R.D. )

    1990-07-01

    Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more cost effective than PF systems when emission control is considered, and, as CFB technology matures, it is expected that an ever-increasing proportion of boiler installations will utilize the CFB concept. CFB systems have advantages in the combustion of low-grade fuels such as coal waste and biomass. In competition with conventional bubbling beds, the CFB boiler often demonstrates superior carbon burn-out efficiency. The key to this combustion technique is the hydrodynamic behavior of the fluidized bed. This article begins with a description of the fundamental fluid dynamic behavior of the CFB system. This is followed by an examination of the combustion process in such an environment and a discussion of the current status of the major CFB technologies.

  15. Coal Bed Methane Primer

    SciTech Connect

    Dan Arthur; Bruce Langhus; Jon Seekins

    2005-05-25

    During the second half of the 1990's Coal Bed Methane (CBM) production increased dramatically nationwide to represent a significant new source of income and natural gas for many independent and established producers. Matching these soaring production rates during this period was a heightened public awareness of environmental concerns. These concerns left unexplained and under-addressed have created a significant growth in public involvement generating literally thousands of unfocused project comments for various regional NEPA efforts resulting in the delayed development of public and fee lands. The accelerating interest in CBM development coupled to the growth in public involvement has prompted the conceptualization of this project for the development of a CBM Primer. The Primer is designed to serve as a summary document, which introduces and encapsulates information pertinent to the development of Coal Bed Methane (CBM), including focused discussions of coal deposits, methane as a natural formed gas, split mineral estates, development techniques, operational issues, producing methods, applicable regulatory frameworks, land and resource management, mitigation measures, preparation of project plans, data availability, Indian Trust issues and relevant environmental technologies. An important aspect of gaining access to federal, state, tribal, or fee lands involves education of a broad array of stakeholders, including land and mineral owners, regulators, conservationists, tribal governments, special interest groups, and numerous others that could be impacted by the development of coal bed methane. Perhaps the most crucial aspect of successfully developing CBM resources is stakeholder education. Currently, an inconsistent picture of CBM exists. There is a significant lack of understanding on the parts of nearly all stakeholders, including industry, government, special interest groups, and land owners. It is envisioned the Primer would being used by a variety of

  16. Bed Rest Muscular Atrophy

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    2000-01-01

    A major debilitating response from prolonged bed rest (BR) is muscle atrophy, defined as a "decrease in size of a part of tissue after full development has been attained: a wasting away of tissue as from disuse, old age, injury or disease". Part of the complicated mechanism for the dizziness, increased body instability, and exaggerated gait in patients who arise immediately after BR may be a result of not only foot pain, but also of muscular atrophy and associated reduction in lower limb strength. Also, there seems to be a close association between muscle atrophy and bone atrophy. A discussion of many facets of the total BR homeostatic syndrome has been published. The old adage that use determines form which promotes function of bone (Wolff's law) also applies to those people exposed to prolonged BR (without exercise training) in whom muscle atrophy is a consistent finding. An extreme case involved a 16-year-old boy who was ordered to bed by his mother in 1932: after 50 years in bed he had "a lily-white frame with limbs as thin as the legs of a ladder-back chair". These findings emphasize the close relationship between muscle atrophy and bone atrophy. In addition to loss of muscle mass during deconditioning, there is a significant loss of muscle strength and a decrease in protein synthesis. Because the decreases in force (strength) are proportionately greater than those in fiber size or muscle cross-sectional area, other contributory factors must be involved; muscle fiber dehydration may be important.

  17. Fluidized-bed sorbents

    SciTech Connect

    Gangwal, S.K.; Gupta, R.P.

    1994-10-01

    The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc oxide-based mixed metal-oxide sorbents for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluidized-bed reactor. In this program, regenerable ZnO-based mixed metal-oxide sorbents are being developed and tested. These include zinc ferrite, zinc titanate, and Z-SORB sorbents. The Z-SORB sorbent is a proprietary sorbent developed by Phillips Petroleum Company (PPCo).

  18. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.; Marasco, J.A.

    1996-02-27

    A fluidized bed reactor system is described which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves. 3 figs.

  19. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.; Marasco, J.A.

    1995-04-25

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figs.

  20. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.

    1993-01-01

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  1. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1996-01-01

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves.

  2. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1995-01-01

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  3. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  4. Particle bed reactor modeling

    NASA Technical Reports Server (NTRS)

    Sapyta, Joe; Reid, Hank; Walton, Lew

    1993-01-01

    The topics are presented in viewgraph form and include the following: particle bed reactor (PBR) core cross section; PBR bleed cycle; fuel and moderator flow paths; PBR modeling requirements; characteristics of PBR and nuclear thermal propulsion (NTP) modeling; challenges for PBR and NTP modeling; thermal hydraulic computer codes; capabilities for PBR/reactor application; thermal/hydralic codes; limitations; physical correlations; comparison of predicted friction factor and experimental data; frit pressure drop testing; cold frit mask factor; decay heat flow rate; startup transient simulation; and philosophy of systems modeling.

  5. Bed drain cover assembly for a fluidized bed

    DOEpatents

    Comparato, Joseph R.; Jacobs, Martin

    1982-01-01

    A loose fitting movable cover plate (36), suitable for the severe service encountered in a fluidized bed combustor (10), restricts the flow of solids into the combustor drain lines (30) during shutdown of the bed. This cover makes it possible to empty spent solids from the bed drain lines which would otherwise plug the piping between the drain and the downstream metering device. This enables use of multiple drain lines each with a separate metering device for the control of solids flow rate.

  6. Modeling of devolatilization in circulating fluidized bed combustion

    SciTech Connect

    Stenseng, M.; Lin, W.; Johnsson, J.E.; Dam-Johansen, K.

    1997-12-31

    A mathematical model is developed to describe the devolatilization process in a circulating fluidized bed combustor. The model is a combination of two submodels: single particle devolatilization and fluid dynamics. The single particle model includes the influence of both chemical kinetics and heat transfer on the rate of devolatilization. The results show a good agreement with literature data. The fluid dynamic model describes the main characteristics of a CFB: a dense zone in the bottom, followed by a splash zone and a dilute zone with a core-annulus structure. Each zone is modeled as a number of CSTR`s and the size and number of CSTR`s has been estimated from tracer experiments in an 80 MW{sub th} CFB boiler. It was not possible to evaluate the model against experimental data, but the dependence of particle size on the degree of devolatilization in the dense bed agrees qualitative with the expected behavior. The mode4l shows that the devolatilization mainly occurs in the dense bed.

  7. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, J.

    1996-03-19

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

  8. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, Juhani

    1996-01-01

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

  9. Impact on Granular Beds

    NASA Astrophysics Data System (ADS)

    van der Meer, Devaraj

    2017-01-01

    The impact of an object on a granular solid is an ubiquitous phenomenon in nature, the scale of which ranges from the impact of a raindrop onto sand all the way to that of a large asteroid on a planet. Despite the obvious relevance of these impact events, the study of the underlying physics mechanisms that guide them is relatively young, with most work concentrated in the past decade. Upon impact, an object starts to interact with a granular bed and experiences a drag force from the sand. This ultimately leads to phenomena such as crater formation and the creation of a transient cavity that upon collapse may cause a jet to appear from above the surface of the sand. This review provides an overview of research that targets these phenomena, from the perspective of the analogous but markedly different impact of an object on a liquid. It successively addresses the drag an object experiences inside a granular bed, the expansion and collapse of the cavity created by the object leading to the formation of a jet, and the remarkable role played by the air that resides within the pores between the grains.

  10. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W.; Taylor, Thomas E.

    1980-01-01

    A steam generator in which a high-velocity, combustion-supporting gas is passed through a bed of particulate material to provide a fluidized bed having a dense-phase portion and an entrained-phase portion for the combustion of fuel material. A first set of heat transfer elements connected to a steam drum is vertically disposed above the dense-phase fluidized bed to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized bed. A second set of heat transfer elements connected to the steam drum and forming the wall structure of the furnace provides a second flow circuit for the heat transfer fluid, the lower portion of which is heated by the dense-phase fluidized bed and the upper portion by the entrained-phase fluidized bed.

  11. Ash level meter for a fixed-bed coal gasifier

    DOEpatents

    Fasching, George E.

    1984-01-01

    An ash level meter for a fixed-bed coal gasifier is provided which utilizes the known ash level temperature profile to monitor the ash bed level. A bed stirrer which travels up and down through the extent of the bed ash level is modified by installing thermocouples to measure the bed temperature as the stirrer travels through the stirring cycle. The temperature measurement signals are transmitted to an electronic signal process system by an FM/FM telemetry system. The processing system uses the temperature signals together with an analog stirrer position signal, taken from a position transducer disposed to measure the stirrer position to compute the vertical location of the ash zone upper boundary. The circuit determines the fraction of each total stirrer cycle time the stirrer-derived bed temperature is below a selected set point, multiplies this fraction by the average stirrer signal level, multiplies this result by an appropriate constant and adds another constant such that a 1 to 5 volt signal from the processor corresponds to a 0 to 30 inch span of the ash upper boundary level. Three individual counters in the processor store clock counts that are representative of: (1) the time the stirrer temperature is below the set point (500.degree. F.), (2) the time duration of the corresponding stirrer travel cycle, and (3) the corresponding average stirrer vertical position. The inputs to all three counters are disconnected during any period that the stirrer is stopped, eliminating corruption of the measurement by stirrer stoppage.

  12. Fluidized bed boiler feed system

    DOEpatents

    Jones, Brian C.

    1981-01-01

    A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

  13. Debris-bed friction of hard-bedded glaciers

    USGS Publications Warehouse

    Cohen, D.; Iverson, N.R.; Hooyer, T.S.; Fischer, U.H.; Jackson, M.; Moore, P.L.

    2005-01-01

    [1] Field measurements of debris-bed friction on a smooth rock tablet at the bed of Engabreen, a hard-bedded, temperate glacier in northern Norway, indicated that basal ice containing 10% debris by volume exerted local shear traction of up to 500 kPa. The corresponding bulk friction coefficient between the dirty basal ice and the tablet was between 0.05 and 0.08. A model of friction in which nonrotating spherical rock particles are held in frictional contact with the bed by bed-normal ice flow can account for these measurements if the power law exponent for ice flowing past large clasts is 1. A small exponent (n < 2) is likely because stresses in ice are small and flow is transient. Numerical calculations of the bed-normal drag force on a sphere in contact with a flat bed using n = 1 show that this force can reach values several hundred times that on a sphere isolated from the bed, thus drastically increasing frictional resistance. Various estimates of basal friction are obtained from this model. For example, the shear traction at the bed of a glacier sliding at 20 m a-1 with a geothermally induced melt rate of 0.006 m a-1 and an effective pressure of 300 kPa can exceed 100 kPa. Debris-bed friction can therefore be a major component of sliding resistance, contradicting the common assumption that debris-bed friction is negligible. Copyright 2005 by the American Geophysical Union.

  14. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R.; Carroll, David W.; Trkula, Mitchell; Anderson, Wallace E.; Valone, Steven M.

    1998-01-01

    A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

  15. Method for packing chromatographic beds

    DOEpatents

    Freeman, David H.; Angeles, Rosalie M.; Keller, Suzanne

    1991-01-01

    Column chromatography beds are packed through the application of static force. A slurry of the chromatography bed material and a non-viscous liquid is filled into the column plugged at one end, and allowed to settle. The column is transferred to a centrifuge, and centrifuged for a brief period of time to achieve a predetermined packing level, at a range generally of 100-5,000 gravities. Thereafter, the plug is removed, other fixtures may be secured, and the liquid is allowed to flow out through the bed. This results in an evenly packed bed, with no channeling or preferential flow characteristics.

  16. Variability of bed drag on cohesive beds under wave action

    USGS Publications Warehouse

    Safak, Ilgar

    2016-01-01

    Drag force at the bed acting on water flow is a major control on water circulation and sediment transport. Bed drag has been thoroughly studied in sandy waters, but less so in muddy coastal waters. The variation of bed drag on a muddy shelf is investigated here using field observations of currents, waves, and sediment concentration collected during moderate wind and wave events. To estimate bottom shear stress and the bed drag coefficient, an indirect empirical method of logarithmic fitting to current velocity profiles (log-law), a bottom boundary layer model for combined wave-current flow, and a direct method that uses turbulent fluctuations of velocity are used. The overestimation by the log-law is significantly reduced by taking turbulence suppression due to sediment-induced stratification into account. The best agreement between the model and the direct estimates is obtained by using a hydraulic roughness of 10  m in the model. Direct estimate of bed drag on the muddy bed is found to have a decreasing trend with increasing current speed, and is estimated to be around 0.0025 in conditions where wave-induced flow is relatively weak. Bed drag shows an increase (up to fourfold) with increasing wave energy. These findings can be used to test the bed drag parameterizations in hydrodynamic and sediment transport models and the skills of these models in predicting flows in muddy environments.

  17. Dynamic bed reactor

    SciTech Connect

    Stormo, K.E.

    1996-07-02

    A dynamic bed reactor is disclosed in which a compressible open cell foam matrix is periodically compressed and expanded to move a liquid or fluid through the matrix. In preferred embodiments, the matrix contains an active material such as an enzyme, biological cell, chelating agent, oligonucleotide, adsorbent or other material that acts upon the liquid or fluid passing through the matrix. The active material may be physically immobilized in the matrix, or attached by covalent or ionic bonds. Microbeads, substantially all of which have diameters less than 50 microns, can be used to immobilize the active material in the matrix and further improve reactor efficiency. A particularly preferred matrix is made of open cell polyurethane foam, which adsorbs pollutants such as polychlorophenol or o-nitrophenol. The reactors of the present invention allow unidirectional non-laminar flow through the matrix, and promote intimate exposure of liquid reactants to active agents such as microorganisms immobilized in the matrix. 27 figs.

  18. Dynamic bed reactor

    SciTech Connect

    Stormo, Keith E.

    1996-07-02

    A dynamic bed reactor is disclosed in which a compressible open cell foam matrix is periodically compressed and expanded to move a liquid or fluid through the matrix. In preferred embodiments, the matrix contains an active material such as an enzyme, biological cell, chelating agent, oligonucleotide, adsorbent or other material that acts upon the liquid or fluid passing through the matrix. The active material may be physically immobilized in the matrix, or attached by covalent or ionic bonds. Microbeads, substantially all of which have diameters less than 50 microns, can be used to immobilize the active material in the matrix and further improve reactor efficiency. A particularly preferred matrix is made of open cell polyurethane foam, which adsorbs pollutants such as polychlorophenol or o-nitrophenol. The reactors of the present invention allow unidirectional non-laminar flow through the matrix, and promote intimate exposure of liquid reactants to active agents such as microorganisms immobilized in the matrix.

  19. Late Wisconsin landform distribution and glacier-bed conditions in Wisconsin

    USGS Publications Warehouse

    Attig, J.W.; Mickelson, D.M.; Clayton, L.

    1989-01-01

    The late Wisconsin Laurentide Ice Sheet advanced across permafrost and reached its maximum extent in Wisconsin between about 18,000 and 15,000 years ago. Deep permafrost persisted in southern Wisconsin until about 14,000 years ago and in northern Wisconsin until about 13,000 years ago. We suggest that during maximum glaciation a zone about 5 km wide in the south and 20 km wide in the north along the margin of the late Wisconsin glacier was frozen to its bed. Meltwater from farther behind the margin, where the bed was at least locally thawed, cut a series of closely spaced tunnel channels through the frozen-bed zone. These channels most likely formed episodically, and they were the source for much of the meltwater-stream sediment deposited in broad outwash plains beyond the ice margin. Frozen-bed conditions near the margin also likely contributed to increased upward shearing of sediment and the accumulation of thicl supraglacial sediment in northern areas. Up ice from the frozen-bed zone the glacier bed was at least locally thawed in a zone about 75 km wide. Extensive drumlin fields formed in the area of the bed that was thawed. By about 13,000 years ago permafrost melted in northern Wisconsin and thawed-bed conditions probably extended to the ice margin throughout Wisconsin and adjacent areas. After about 13,000 years ago in northern Wisconsin the glacier was sliding on its bed and forming drumlins out to the ice margin, and thick supraglacial sediment no longer accumulated. ?? 1989.

  20. Mathematical Model of Hydraulic Fracturing of a Bed

    NASA Astrophysics Data System (ADS)

    Goncharova, G. S.; Khramchenkov, M. G.

    2016-07-01

    A study has been made of the problem on the process of formation of a zone of higher-than-average permeability with a moving boundary in an initially low-permeability porous medium (problem on hydraulic fracturing of a bed) in a three-dimensional formulation. A characteristic feature of the three-dimensional problem was the taking into account the existence of two zones (zone with a regular permeability and the destruction zone) in the porous medium, whose contact region was determined using the condition of mass balance on the moving boundary. Special features fundamental to the process of mass transfer in such filtration-inhomogeneous porous media have been revealed and analyzed.

  1. Bed Bug Laws and Regulations

    EPA Pesticide Factsheets

    21 states have some level of regulation with regard to bed bugs. Most of these requirements focus on hotels and landlords or other property managers. The Department of Housing and Urban Development has guidance on controlling bed bugs in public housing.

  2. LSP Composite Test Bed Design

    NASA Technical Reports Server (NTRS)

    Day, Arthur C.; Griess, Kenneth H.

    2013-01-01

    This document provides standalone information for the Lightning Strike Protection (LSP) Composite Substrate Test Bed Design. A six-sheet drawing set is reproduced for reference, as is some additional descriptive information on suitable sensors and use of the test bed.

  3. SMART NAS Test Bed Overview

    NASA Technical Reports Server (NTRS)

    Palopo, Kee

    2016-01-01

    These slides presents an overview of SMART NAS Test Bed. The test bed is envisioned to be connected to operational systems and to allow a new concept and technology to be evaluated in its realistic environment. Its role as an accelerator of concepts and technologies development, its use-case-driven development approach, and its state are presented.

  4. Effectiveness of Bed Bug Pesticides

    EPA Pesticide Factsheets

    Before EPA allows a bed bug claim on a label, the product must be supported by data showing it will kill bed bugs when applied according to the label. Also take into accounts factors such as extent of infestation, site preparation, and insect life stages.

  5. Ability of bed bug-detecting canines to locate live bed bugs and viable bed bug eggs.

    PubMed

    Pfiester, Margie; Koehler, Philip G; Pereira, Roberto M

    2008-08-01

    The bed bug, Cimex lectularius L., like other bed bug species, is difficult to visually locate because it is cryptic. Detector dogs are useful for locating bed bugs because they use olfaction rather than vision. Dogs were trained to detect the bed bug (as few as one adult male or female) and viable bed bug eggs (five, collected 5-6 d after feeding) by using a modified food and verbal reward system. Their efficacy was tested with bed bugs and viable bed bug eggs placed in vented polyvinyl chloride containers. Dogs were able to discriminate bed bugs from Camponotus floridanus Buckley, Blattella germanica (L.), and Reticulitermes flavipes (Kollar), with a 97.5% positive indication rate (correct indication of bed bugs when present) and 0% false positives (incorrect indication of bed bugs when not present). Dogs also were able to discriminate live bed bugs and viable bed bug eggs from dead bed bugs, cast skins, and feces, with a 95% positive indication rate and a 3% false positive rate on bed bug feces. In a controlled experiment in hotel rooms, dogs were 98% accurate in locating live bed bugs. A pseudoscent prepared from pentane extraction of bed bugs was recognized by trained dogs as bed bug scent (100% indication). The pseudoscent could be used to facilitate detector dog training and quality assurance programs. If trained properly, dogs can be used effectively to locate live bed bugs and viable bed bug eggs.

  6. Grate assembly for fixed-bed coal gasifier

    DOEpatents

    Notestein, John E.

    1993-01-01

    A grate assembly for a coal gasifier of a moving-bed or fixed-bed type is provided for crushing agglomerates of solid material such as clinkers, tailoring the radial distribution of reactant gases entering the gasification reaction zone, and control of the radial distribution of downwardly moving solid velocities in the gasification and combustion zone. The clinker crushing is provided by pinching clinkers between vertically oriented stationary bars and angled bars supported on the upper surface of a rotating conical grate. The distribution of the reactant gases is provided by the selective positioning of horizontally oriented passageways extending through the grate. The radial distribution of the solids is provided by mounting a vertically and generally radially extending scoop mechanism on the upper surface of the grate near the apex thereof.

  7. Novel Simulated moving bed technologies

    SciTech Connect

    Purdue University

    2003-12-30

    Cellulose and hemicellulose from plants and other biomass can be hydrolyzed to produce sugars (i.e. glucose and xylose). Once these sugars are separated from other impurities, they can serve as feedstock in fermentation to produce ethanol (as fuels), lactic acid, or other valuable chemicals. The need for producing fuels and chemicals from renewable biomass has become abundantly clear over the last decade. However, the cost of producing fermentable sugars from biomass hydrolyzate using existing technology is relatively high and has been a major obstacle. The objective of this project is to develop an efficient and economical simulated moving bed (SMB) process to recover fermentable sugars from biomass hydrolyzate. Sulfuric acid can hydrolyze the cellulose and hemicellulose in biomass to sugars, but this process can generate byproducts such as acetic acid, and can lead to further degradation of the xylose to furfural and glucose to hydroxymethyl furfural (HMF). Also, lignin and other compounds in the biomass will degrade to various phenolic compounds. If the concentrations of these compounds exceed certain threshold levels, they will be toxic to the downstream fermentation, and will severely limit the usefulness of the derived sugars. Standard post-hydrolysis processing involves neutralization of sulfuric acid, usually with lime (calcium hydroxide). A study by Wooley et al.showed that the limed hydrolyzate gave a low ethanol yield in fermentation test (20% of theoretical yield compared to 77% of theoretical yield from fermentation of pure sugars). They showed that instead of adding lime, an ion exclusion chromatography process could be used to remove acids, as well as to isolate the sugars from the biomass hydrolyzate. In this project, we investigated the feasibility of developing an economical SMB process based on (1) a polymeric adsorbent, Dowex99, which was used by Wooley et al., (2) a second polymeric adsorbent, poly-4-vinyl pyridine (or PVP in short, Reilly

  8. Occurrence and significance of Silurian K-bentonite beds at Arisaig, Nova Scotia, eastern Canada

    USGS Publications Warehouse

    Bergstrom, Stig M.; Huff, W.D.; Kolata, Dennis R.; Melchin, Michael J.

    1997-01-01

    The most extensive succession of K-bentonite beds known in the Silurian of North America occurs at Arisaig on the northern coast of Nova Scotia. At least 40 ash beds are present in the Llandoverian Ross Brook Formation and at least four in the early Ludlovian McAdam Brook Formation. Most of the beds are thin (<5 cm), but one bed (the Smith Brook K-bentonite bed) in the late Llandoverian crenulata Zone and another (the McAdam Brook K-bentonite bed) in the early Ludlovian nilssoni Zone each reach a thickness of 20 cm. New graptolite collections provide critical information on the biostratigraphic position of the K-bentonite beds in the Ross Brook Formation. Geochemical data show that the Arisaig ash beds represent calc-alkaline magmas from plate margin, subduction-related volcanic vents. Differences in K-bentonite stratigraphie distribution, combined with paleogeographic considerations, suggest that the volcanoes were located much farther to the south in the Iapetus than the source volcanoes of the British - Baltoscandian Llandoverian K-bentonites.

  9. Method for using fast fluidized bed dry bottom coal gasification

    DOEpatents

    Snell, George J.; Kydd, Paul H.

    1983-01-01

    Carbonaceous solid material such as coal is gasified in a fast fluidized bed gasification system utilizing dual fluidized beds of hot char. The coal in particulate form is introduced along with oxygen-containing gas and steam into the fast fluidized bed gasification zone of a gasifier assembly wherein the upward superficial gas velocity exceeds about 5.0 ft/sec and temperature is 1500.degree.-1850.degree. F. The resulting effluent gas and substantial char are passed through a primary cyclone separator, from which char solids are returned to the fluidized bed. Gas from the primary cyclone separator is passed to a secondary cyclone separator, from which remaining fine char solids are returned through an injection nozzle together with additional steam and oxygen-containing gas to an oxidation zone located at the bottom of the gasifier, wherein the upward gas velocity ranges from about 3-15 ft/sec and is maintained at 1600.degree.-200.degree. F. temperature. This gasification arrangement provides for increased utilization of the secondary char material to produce higher overall carbon conversion and product yields in the process.

  10. Modeling biomass gasification in circulating fluidized beds

    NASA Astrophysics Data System (ADS)

    Miao, Qi

    In this thesis, the modeling of biomass gasification in circulating fluidized beds was studied. The hydrodynamics of a circulating fluidized bed operating on biomass particles were first investigated, both experimentally and numerically. Then a comprehensive mathematical model was presented to predict the overall performance of a 1.2 MWe biomass gasification and power generation plant. A sensitivity analysis was conducted to test its response to several gasifier operating conditions. The model was validated using the experimental results obtained from the plant and two other circulating fluidized bed biomass gasifiers (CFBBGs). Finally, an ASPEN PLUS simulation model of biomass gasification was presented based on minimization of the Gibbs free energy of the reaction system at chemical equilibrium. Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). A 2-dimensional mathematical model was developed considering the hydrodynamic behavior of CFB gasifiers. In the modeling, the CFB riser was divided into two regions: a dense region at the bottom and a dilute region at the top of the riser. Kunii and Levenspiel (1991)'s model was adopted to express the vertical solids distribution with some other assumptions. Radial distributions of bed voidage were taken into account in the upper zone by using Zhang et al. (1991)'s correlation. For model validation purposes, a cold model CFB was employed, in which sawdust was transported with air as the fluidizing agent. A comprehensive mathematical model was developed to predict the overall performance of a 1.2 MWe biomass gasification and power generation demonstration plant in China. Hydrodynamics as well as chemical reaction kinetics were considered. The fluidized bed riser was divided into two distinct sections: (a) a dense region at the bottom of the bed where biomass undergoes mainly heterogeneous reactions and (b) a dilute region at the top where most of homogeneous

  11. Economic and environmental benefits of fluidized bed

    SciTech Connect

    Maitland, J.

    1997-12-31

    The control of sulfur dioxide and nitrogen oxides within the process design, with little need for additional environmental controls external to the boiler, is a unique feature of the fluid bed technology. CFB`s unparalleled ability to achieve low NOx emissions is possible due to its low combustion temperature and by the careful design of air admission to the combustion zones. The addition of selected sorbents to capture sulfur dioxide within the boiler results in low SOx emissions and a dry waste product for ease of disposal. This paper will focus on the design and operating performance of CFBs from the environmental viewpoint. What factors affect emissions? What options are available? Case histories will be used to illustrate the proven track record of CFB in meeting specific emissions requirements for different plant sites.

  12. Particle pressures in fluidized beds

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C.; Potapov, A.V.

    1992-01-01

    This is an experimental project to make detailed measurements of the particle pressures generated in fluidized beds. The focus lies in two principle areas: (1) the particle pressure distribution around single bubbles rising in a two-dimensional gas-fluidized bed and (2) the particle pressures measured in liquid-fluidized beds. This first year has largely been to constructing the experiments The design of the particle pressure probe has been improved and tested. A two-dimensional gas-fluidized bed has been constructed in order to measure the particle pressure generated around injected bubbles. The probe is also being adapted to work in a liquid fluidized bed. Finally, a two-dimensional liquid fluidized bed is also under construction. Preliminary measurements show that the majority of the particle pressures are generated in the wake of a bubble. However, the particle pressures generated in the liquid bed appear to be extremely small. Finally, while not directly associated with the particle pressure studies, some NERSC supercomputer time was granted alongside this project. This is being used to make large scale computer simulation of the flow of granular materials in hoppers.

  13. Avionics test bed development plan

    NASA Technical Reports Server (NTRS)

    Harris, L. H.; Parks, J. M.; Murdock, C. R.

    1981-01-01

    A development plan for a proposed avionics test bed facility for the early investigation and evaluation of new concepts for the control of large space structures, orbiter attached flex body experiments, and orbiter enhancements is presented. A distributed data processing facility that utilizes the current laboratory resources for the test bed development is outlined. Future studies required for implementation, the management system for project control, and the baseline system configuration are defined. A background analysis of the specific hardware system for the preliminary baseline avionics test bed system is included.

  14. Concentration and Velocity Gradients in Fluidized Beds

    NASA Technical Reports Server (NTRS)

    McClymer, James P.

    2003-01-01

    In this work we focus on the height dependence of particle concentration, average velocity components, fluctuations in these velocities and, with the flow turned off, the sedimentation velocity. The latter quantities are measured using Particle Imaging Velocimetry (PIV). The PIV technique uses a 1-megapixel camera to capture two time-displaced images of particles in the bed. The depth of field of the imaging system is approximately 0.5 cm. The camera images a region with characteristic length of 2.6 cm for the small particles and 4.7 cm. for the large particles. The local direction of particle flow is determined by calculating the correlation function for sub-regions of 32 x 32 pixels. The velocity vector map is created from this correlation function using the time between images (we use 15 to 30 ms). The software is sensitive variations of 1/64th of a pixel. We produce velocity maps at various heights, each consisting of 3844 velocities. We break this map into three vertical zones for increased height information. The concentration profile is measured using an expanded (1 cm diameter) linearly polarized HeNe Laser incident on the fluidized bed. A COHU camera (gamma=1, AGC off) with a lens and a polarizer images the transmitted linearly polarized light to minimize the effects of multiply scattered light. The intensity profile (640 X 480 pixels) is well described by a Gaussian fit and the height of the Gaussian is used to characterize the concentration. This value is compared to the heights found for known concentrations. The sedimentation velocity is estimated using by imaging a region near the bottom of the bed and using PIV to measure the velocity as a function of time. With a nearly uniform concentration profile, the time can be converted to height information. The stable fluidized beds are made from large pseudo-monodisperse particles (silica spheres with radii (250-300) microns and (425-500) microns) dispersed in a glycerin/water mix. The Peclet number is

  15. Print a Bed Bug Card

    EPA Pesticide Factsheets

    Two sets of business card-sized lists of tips for prevention of bed bug infestations, one for general use around home, the other for travelers. Print a single card or a page of cards for distribution.

  16. Getting Rid of Bed Bugs

    MedlinePlus

    Jump to main content US EPA United States Environmental Protection Agency Search Search Bed Bugs Share Facebook Twitter ... integrated pest management. Preparing for control is very important whether you are considering hiring a professional or ...

  17. Flight Analogs (Bed Rest Research)

    NASA Video Gallery

    Flight Analogs / Bed Rest Research Projects provide NASA with a ground based research platform to complement space research. By mimicking the conditions of weightlessness in the human body here on ...

  18. Bed Bugs: The Australian Response

    PubMed Central

    Doggett, Stephen L.; Orton, Christopher J.; Lilly, David G.; Russell, Richard C.

    2011-01-01

    Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia. PMID:26467616

  19. Bed Bug Clearinghouse by Audience

    EPA Pesticide Factsheets

    This information is intended to help states, communities, and consumers prevent and control bed bug infestations. Find materials for emergency and health facilities, hotels, housing authorities, landlords, schools, pest management professionals, and more.

  20. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-10-01

    The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.

  1. Bed Bugs: The Australian Response.

    PubMed

    Doggett, Stephen L; Orton, Christopher J; Lilly, David G; Russell, Richard C

    2011-04-15

    Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard 'A Code of Practice for the Control of Bed Bug Infestations in Australia' that defines and promotes 'best practice' in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in 'best practice' while bed bugs remain problematic in Australia.

  2. Operating characteristics of rotating beds

    SciTech Connect

    Keyvani, M.; Gardner, N.C.

    1988-01-01

    Vapor-liquid contacting in high gravitational fields offers prospects for significant reductions in the physical size, capital, and operating costs of packed towers. Pressure drops, power requirements, mass transfer coefficients and liquid residence time distributions are reported for a rotating bed separator. The beds studied were rigid, foamed aluminum, with specific surface areas ranging from 650 to 3000 m{sup 2}/m{sup 2}. Gravitational fields were varied from 50 to 300g.

  3. Bed bugs in healthcare settings.

    PubMed

    Munoz-Price, L Silvia; Safdar, Nasia; Beier, John C; Doggett, Stephen L

    2012-11-01

    Infestations caused by bed bugs have resurfaced during the past decade across all continents. Even though bed bugs primarily cause skin manifestations in humans, a major stigma is placed upon people or institutions found to carry them. It is important for healthcare facilities to be prepared for this pest by implementing policies, carefully selecting materials used for hospital furniture, and educating providers on early identification and control.

  4. Fluidized bed heat exchanger with water cooled air distributor and dust hopper

    DOEpatents

    Jukkola, Walfred W.; Leon, Albert M.; Van Dyk, Jr., Garritt C.; McCoy, Daniel E.; Fisher, Barry L.; Saiers, Timothy L.; Karstetter, Marlin E.

    1981-11-24

    A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

  5. FY-2015 Methyl Iodide Deep-Bed Adsorption Test Report

    SciTech Connect

    Soelberg, Nicholas Ray; Watson, Tony Leroy

    2015-09-30

    Nuclear fission produces fission and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2015 according to a multi-laboratory methyl iodide adsorption test plan. Updates to the deep-bed test system have also been performed to enable the inclusion of evaporated HNO3 and increased NO2 concentrations in future tests. This report summarizes the result of those activities. Test results showed that iodine adsorption from gaseous methyl iodide using reduced silver zeolite (AgZ) resulted in initial iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) under 1,000 for the conditions of the long-duration test performed this year (45 ppm CH3I, 1,000 ppm each NO and NO2, very low H2O levels [3 ppm] in balance air). The mass transfer zone depth exceeded the cumulative 5-inch depth of 4 bed segments, which is deeper than the 2-4 inch depth estimated for the mass transfer zone for adsorbing I2 using AgZ in prior deep-bed tests. The maximum iodine adsorption capacity for the AgZ under the conditions of this test was 6.2% (6.2 g adsorbed I per 100 g sorbent). The maximum Ag utilization was 51%. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  6. Effect of bed pressure drop on performance of a CFB boiler

    SciTech Connect

    Hairui Yang; Hai Zhang; Shi Yang; Guangxi Yue; Jun Su; Zhiping Fu

    2009-05-15

    The effect of bed pressure drop and bed inventory on the performances of a circulating fluidized bed (CFB) boiler was studied. By using the state specification design theory, the fluidization state of the gas-solids flow in the furnace of conventional CFB boilers was reconstructed to operate at a much lower bed pressure drop by reducing bed inventory and control bed quality. Through theoretical analysis, it was suggested that there would exist a theoretical optimal value of bed pressure drop, around which the boiler operation can achieve the maximal combustion efficiency and with significant reduction of the wear of the heating surface and fan energy consumption. The analysis was validated by field tests carried out in a 75 t/h CFB boiler. At full boiler load, when bed pressure drop was reduced from 7.3 to 3.2 kPa, the height of the dense zone in the lower furnace decreased, but the solid suspension density profile in the upper furnace and solid flow rate were barely influenced. Consequently, the average heat transfer coefficient in the furnace was kept nearly the same and the furnace temperature increment was less than 17{sup o}C. It was also found that the carbon content in the fly ash decreased first with decreasing bed pressure drop and then increased with further increasing bed pressure drop. The turning point with minimal carbon content was referred to as the point with optimal bed pressure drop. For this boiler, at the optimum point the bed pressure was around 5.7 kPa with the overall excess air ratio of 1.06. When the boiler was operated around this optimal point, not only the combustion efficiency was improved, but also fan energy consumption and wear of heating surface were reduced. 23 refs., 6 figs., 4 tabs.

  7. Quantifying fluid and bed dynamics for characterizing benthic physical habitat in large rivers

    USGS Publications Warehouse

    Gaeuman, D.; Jacobson, R.B.

    2007-01-01

    Sturgeon use benthic habitats in and adjacent to main channels where environmental conditions can include bedload sediment transport and high near-bed flow velocities. Bed velocity measurements obtained with acoustic Doppler instruments provide a means to assess the concentration and velocity of sediment moving near the streambed, and are thus indicative of the bedload sediment transport rate, the near-bed flow velocity, and the stability of the substrate. Acoustic assessments of benthic conditions in the Missouri River were conducted at scales ranging from the stream reach to individual bedforms. Reach-scale results show that spatially-averaged bed velocities in excess of 0.5 m s-1 frequently occur in the navigation channel. At the local scale, bed velocities are highest near bedform crests, and lowest in the troughs. Low-velocity zones can persist in areas with extremely high mean bed velocities. Use of these low-velocity zones may allow sturgeon to make use of portions of the channel where the average conditions near the bed are severe. To obtain bed velocity measurements of the highest possible quality, it is necessary to extract bottom-track and GPS velocity information from the raw ADCP data files on a ping-by-ping basis. However, bed velocity measured from a point can also be estimated using a simplified method that is more easily implemented in the context of routine monitoring. The method requires only the transect distance and direction data displayed in standard ADCP data-logging software. Bed velocity estimates obtained using this method are usually within 5-10% of estimates obtained from ping-by-ping processing. ?? 2007 Blackwell Verlag.

  8. Rapid ignition of fluidized bed boiler

    DOEpatents

    Osborn, Liman D.

    1976-12-14

    A fluidized bed boiler is started up by directing into the static bed of inert and carbonaceous granules a downwardly angled burner so that the hot gases cause spouting. Air is introduced into the bed at a rate insufficient to fluidize the entire bed. Three regions are now formed in the bed, a region of lowest gas resistance, a fluidized region and a static region with a mobile region at the interface of the fluidized and static regions. Particles are transferred by the spouting action to form a conical heap with the carbonaceous granules concentrated at the top. The hot burner gases ignite the carbonaceous matter on the top of the bed which becomes distributed in the bed by the spouting action and bed movement. Thereafter the rate of air introduction is increased to fluidize the entire bed, the spouter/burner is shut off, and the entire fluidized bed is ignited.

  9. Space station propulsion test bed

    NASA Technical Reports Server (NTRS)

    Briley, G. L.; Evans, S. A.

    1989-01-01

    A test bed was fabricated to demonstrate hydrogen/oxygen propulsion technology readiness for the intital operating configuration (IOC) space station application. The test bed propulsion module and computer control system were delivered in December 1985, but activation was delayed until mid-1986 while the propulsion system baseline for the station was reexamined. A new baseline was selected with hydrogen/oxygen thruster modules supplied with gas produced by electrolysis of waste water from the space shuttle and space station. As a result, an electrolysis module was designed, fabricated, and added to the test bed to provide an end-to-end simulation of the baseline system. Subsequent testing of the test bed propulsion and electrolysis modules provided an end-to-end demonstration of the complete space station propulsion system, including thruster hot firings using the oxygen and hydrogen generated from electrolysis of water. Complete autonomous control and operation of all test bed components by the microprocessor control system designed and delivered during the program was demonstrated. The technical readiness of the system is now firmly established.

  10. Clinical physiology of bed rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1993-01-01

    Maintenance of optimal health in humans requires the proper balance between exercise, rest, and sleep as well as time in the upright position. About one-third of a lifetime is spent sleeping; and it is no coincidence that sleeping is performed in the horizontal position, the position in which gravitational influence on the body is minimal. Although enforced bed rest is necessary for the treatment of some ailments, in some cases it has probably been used unwisely. In addition to the lower hydrostatic pressure with the normally dependent regions of the cardiovascular system, body fuid compartments during bed rest in the horizontal body position, and virtual elimination of compression on the long bones of the skeletal system during bed rest (hypogravia), there is often reduction in energy metabolism due to the relative confinement (hypodynamia) and alteration of ambulatory circadian variations in metabolism, body temperature, and many hormonal systems. If patients are also moved to unfamiliar surroundings, they probably experience some feelings of anxiety and some sociopsychological problems. Adaptive physiological responses during bed rest are normal for that environment. They are attempts by the body to reduce unnecessary energy expenditure, to optimize its function, and to enhance its survival potential. Many of the deconditioning responses begin within the first day or two of bed rest; these early responses have prompted physicians to insist upon early resumption of the upright posture and ambulation of bedridden patients.

  11. Stratigraphic relationship between Odontogryphaea Thirsae beds and big shale of Wilcox (Paleocene-Eocene) in Louisiana

    SciTech Connect

    Glawe, L.N. )

    1989-09-01

    The relationship between beds of the oyster Odontogryphaea thirsae, of the surface Wilcox Group exposures in the Sabine uplift area of northwestern Louisiana and the Big Shale, a well-known subsurface mapping unit in central Louisiana, has been unclear. In a paleontological study of 2,158 ft of continuous Wilcox core from Sabine Parish, planktonic foraminiferal biostratigraphic zones were determined that include: Globorotalia angulata and G. pusilla (P3), G. Pseudomenardii (P4), and G. velascoensis (P5). The O. thirsae bed was assigned to the G. Pseudomenardii zone. Electrical-log cross sections were used to demonstrate (1) the correlation between the O. thirsae bed in the core hole and the O. thirsae bed exposed at the surface at Many, Louisiana, a distance of 6 mi and (2) the correlation between the base of the 10-ft thick shale beneath the O. thirsae bed in the core hole and the base of the Big Shale as recognized in the central Louisiana subsurface. Based on its assigned biostratigraphic zone, The O. thirsae bed in the updip Wilcox core hole is equivalent, in part, to the Big Shale of the basinal Wilcox of east-central Louisiana, which previously has been included in the G. pseudomenardii zone. Paleontological recognition of a thin marine unit 1 ft above the O. thirsae bed in the core hole on the southern flank of the Sabine uplift provides documentation of the transgressive character of the Big Shale - O. thirsae sequence and is evidence of the TP 2.1 cycle in Louisiana.

  12. Model for boiling and dryout in particle beds. [LMFBR

    SciTech Connect

    Lipinski, R. J.

    1982-06-01

    Over the last ten years experiments and modeling of dryout in particle beds have produced over fifty papers. Considering only volume-heated beds, over 250 dryout measurements have been made, and are listed in this work. In addition, fifteen models to predict dryout have been produced and are discussed. A model is developed in this report for one-dimensional boiling and dryout in a porous medium. It is based on conservation laws for mass, momentum, and energy. The initial coupled differential equations are reduced to a single first-order differential equation with an algebraic equation for the upper boundary condition. The model includes the effects of both laminar and turbulent flow, two-phase friction, and capillary force. The boundary condition at the bed bottom includes the possibility of inflowing liquid and either an adiabatic or a bottom-cooled support structure. The top of the bed may be either channeled or subcooled. In the first case the channel length and the saturation at the base of the channels are predicted. In the latter case, a criterion for penetration of the subcooled zone by channels is obtained.

  13. Staged cascade fluidized bed combustor

    DOEpatents

    Cannon, Joseph N.; De Lucia, David E.; Jackson, William M.; Porter, James H.

    1984-01-01

    A fluid bed combustor comprising a plurality of fluidized bed stages interconnected by downcomers providing controlled solids transfer from stage to stage. Each stage is formed from a number of heat transfer tubes carried by a multiapertured web which passes fluidizing air to upper stages. The combustor cross section is tapered inwardly from the middle towards the top and bottom ends. Sorbent materials, as well as non-volatile solid fuels, are added to the top stages of the combustor, and volatile solid fuels are added at an intermediate stage.

  14. Flow separation and shear stress over angle-of-repose bed forms: A numerical investigation

    NASA Astrophysics Data System (ADS)

    Lefebvre, Alice; Paarlberg, Andries J.; Winter, Christian

    2014-02-01

    Large asymmetric bed forms commonly develop in rivers. The turbulence associated with flow separation that develops over their steep lee side is responsible for the form shear stress which can represent a substantial part of total shear stress in rivers. This paper uses the Delft3D modeling system to investigate the effects of bed form geometry and forcing conditions on flow separation length and associated turbulence, and bed form shear stress over angle-of-repose (30° lee side angle) bed forms. The model was validated with lab measurements that showed sufficient agreement to be used for a systematic analysis. The influence of flow velocity, bed roughness, relative height (bed form height/water depth), and aspect ratio (bed form height/length) on the variations of the normalized length of the flow separation zone, the extent of the wake region (where the turbulent kinetic energy (TKE) was more than 70% of the maximum TKE), the average TKE within the wake region and the form shear stress were investigated. Form shear stress was found not to scale with the size of the flow separation zone but to be related to the product of the normalized extent of the wake region (extent of the wake region/extent of water body above the bed form) and the average TKE within the wake region. The results add to understanding of the hydrodynamics of bed forms and may be used for the development of better parameterizations of small-scale processes for application in large-scale studies.

  15. Bed material agglomeration during fluidized bed combustion. Final report

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

    1996-01-01

    The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion of coal and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed combustors (FBCs) indicate that at least five boilers were experiencing some form of bed material agglomeration. Deposit formation was reported at nine sites with deposits most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Three general types of mineralogic reactions were observed to occur in the agglomerates and deposits. Although alkalies may play a role with some {open_quotes}high alkali{close_quotes} lignites, we found agglomeration was initiated due to fluxing reactions between iron (II) from pyrites and aluminosilicates from clays. This is indicated by the high amounts of iron, silica, and alumina in the agglomerates and the mineralogy of the agglomerates. Agglomeration likely originated in the dense phase of the FBC bed within the volatile plume which forms when coal is introduced to the boiler. Secondary mineral reactions appear to occur after the agglomerates have formed and tend to strengthen the agglomerates. When calcium is present in high amounts, most of the minerals in the resulting deposits are in the melilite group (gehlenite, melilite, and akermanite) and pyroxene group (diopside and augite). During these solid-phase reactions, the temperature of formation of the melilite minerals can be lowered by a reduction of the partial pressure of CO{sub 2} (Diopside + Calcite {r_arrow}Akermanite).

  16. Apparatus and process for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1985-10-01

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

  17. Advances in the optimization of moving bed Sasol-Lurgi gasifiers

    SciTech Connect

    Ranwell, P.; Greyvenstein, G.P.

    1998-12-31

    During the past ten years there have been significant advances in the development of the Sasol Lurgi gasifier. In 1987 some of the Mark IV Gasifiers in Sasolburg, South Africa were decommissioned and flushed with water, the coal and ash bed were then excavated from the top, layer by layer, in order to examine the three dimensional profile of the ash bed at the bottom of the gasifier. These excavations showed that the ash bed and oxidation zone have an axial symmetric ``W`` shape if viewed from the side. It was argued that this shape played an important role by influencing the stable operation of the gasifier. Most studies and modifications that followed were attempts to correct or adjust this particular shape to a more homogeneous and flat ash bed. In this paper the mechanism that determines the three dimensional shape of the ash bed were investigated. A computational fluid dynamic model was used to study the chemical reacting flow of gas in a packed coal bed. With this model it was possible to determine the key parameters that influences the shape of the oxidation zone and therefore the operation of the gasifier.

  18. Char binder for fluidized beds

    DOEpatents

    Borio, Richard W.; Accortt, Joseph I.

    1981-01-01

    An arrangement that utilizes agglomerating coal as a binder to bond coal fines and recycled char into an agglomerate mass that will have suitable retention time when introduced into a fluidized bed 14 for combustion. The simultaneous use of coal for a primary fuel and as a binder effects significant savings in the elimination of non-essential materials and processing steps.

  19. How to Find Bed Bugs

    EPA Pesticide Factsheets

    Find and correctly identify an infestation early before it becomes widespread. Look for rusty or reddish stains and pinpoint dark spots on bed sheets or mattresses, and search for bugs near the piping, seams and tags of the mattress and box spring.

  20. Laboratory rearing of bed bugs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The resurgence of bed bugs Cimex lectularius L. in the United States and worldwide has resulted in an increase in research by university, government, and industry scientists directed at the biology and control of this blood-sucking pest. A need has subsequently arisen for producing sufficient biolog...

  1. Physiology Of Prolonged Bed Rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1991-01-01

    Report describes physiological effects of prolonged bed rest. Rest for periods of 24 hours or longer deconditions body to some extent; healing proceeds simultaneously with deconditioning. Report provides details on shifts in fluid electrolytes and loss of lean body mass, which comprises everything in body besides fat - that is, water, muscle, and bone. Based on published research.

  2. Electromechanics of packed granular beds

    SciTech Connect

    Robinson, K.S.

    1982-01-01

    Strong, electrical, interparticle forces are induced by applied electric fields within packed beds of dielectric particles. Proposed applications utilizing electropacked beds (EPBs) or electrofluidized beds (EFBs) include air filtration and gas clean-up, fine particle separation, commercial drying and coating processes, heat and mass transfer, and bulk bed control. A new distributed circuit model of the electrical interparticle force is presented that identifies the role of surface roughness as determining the interparticle spacing. The dc steady state force is predicted to increase nearly linearly with the applied electric field and is theoretically independent of particle surface conductivity. The electric stress is found to vary nearly linearly with the applied electric field. Data are generally consistent with the theoretical contention that increased surface roughness decreases electromechanical effects. Surface conductivity variations of three to four times have no measurable effect on the dc steady state electric stress. The electric stress is insensitive to the dielectric properties of the interstitial gas eliminating Townsend discharge as a candidate for the nonlinear charge transport process thought to occur near interparticle contacts. The theoretical upper bound of the electric stress calculated using the distributed circuit model falls within the scatter of the data if a limit on the electric field in the interparticle gap which models nonlinear charge transport is in the range of 1 to 6 x 10/sup 7/ V/m. Estimates of the charge relaxation time using transient angle of repose experiments are somewhat smaller but comparable with theoretical values calculated by ignoring nonlinear charge transport.

  3. Quality of economically extractable coal beds in the Gillette coal field as compared with other Tertiary coal beds in the Powder River basin, Wyoming and Montana

    USGS Publications Warehouse

    Ellis, Margaret S.

    2002-01-01

    The Powder River Basin, and specifically the Gillette coal field, contains large quantities of economically extractable coal resources. These coal resources have low total sulfur content and ash yield, and most of the resources are subbituminous in rank. A recent U.S Geological Survey study of economically extractable coal in the Gillette coal field focused on five coal beds, the Wyodak rider, Upper Wyodak, Canyon, Lower Wyodak-Werner, and Gates/Kennedy. This report compares the coal quality of these economically extractable coal beds to coal in the Wyodak-Anderson coal zone in the Powder River Basin and in the Gillette coal field (Flores and others, 1999) and other produced coal in the Gillette coal field (Glass, 2000). The Upper Wyodak, Canyon, and Lower Wyodak/Werner beds are within the Wyodak-Anderson coal zone. Compared with all coal in the Wyodak-Anderson coal zone, both throughout the Powder River Basin and just within the Gillette coal field; the thick, persistent Upper Wyodak coal bed in the Gillette coal field has higher mean gross calorific value (8,569 Btu/lb), lower mean ash yield (5.8 percent), and lower mean total sulfur content (0.46 percent).

  4. The NASA Bed Rest Project

    NASA Technical Reports Server (NTRS)

    Rhodes, Bradley; Meck, Janice

    2005-01-01

    NASA s National Vision for Space Exploration includes human travel beyond low earth orbit and the ultimate safe return of the crews. Crucial to fulfilling the vision is the successful and timely development of countermeasures for the adverse physiological effects on human systems caused by long term exposure to the microgravity environment. Limited access to in-flight resources for the foreseeable future increases NASA s reliance on ground-based analogs to simulate these effects of microgravity. The primary analog for human based research will be head-down bed rest. By this approach NASA will be able to evaluate countermeasures in large sample sizes, perform preliminary evaluations of proposed in-flight protocols and assess the utility of individual or combined strategies before flight resources are requested. In response to this critical need, NASA has created the Bed Rest Project at the Johnson Space Center. The Project establishes the infrastructure and processes to provide a long term capability for standardized domestic bed rest studies and countermeasure development. The Bed Rest Project design takes a comprehensive, interdisciplinary, integrated approach that reduces the resource overhead of one investigator for one campaign. In addition to integrating studies operationally relevant for exploration, the Project addresses other new Vision objectives, namely: 1) interagency cooperation with the NIH allows for Clinical Research Center (CRC) facility sharing to the benefit of both agencies, 2) collaboration with our International Partners expands countermeasure development opportunities for foreign and domestic investigators as well as promotes consistency in approach and results, 3) to the greatest degree possible, the Project also advances research by clinicians and academia alike to encourage return to earth benefits. This paper will describe the Project s top level goals, organization and relationship to other Exploration Vision Projects, implementation

  5. Heat exchanges between a fluidized bed and small-sized bodies

    SciTech Connect

    Teplitskii, Yu.S.

    1995-06-01

    On the basis of the two-zone model, a procedure is developed for calculating the complex heat exchange of a probe of small dimensions (comparable with the diameter of the bed particles). The procedure takes into account the influence of the fluidizing agent pressure.

  6. DEVELOPMENT OF A METHODOLOGY FOR REGIONAL EVALUATION OF CONFINING BED INTEGRITY

    EPA Science Inventory

    For safe underground injection of liquid waste, confining formations must be thick, extensive, and have low permeability. Recognition of faults that extend from the potential injection zone to underground sources of drinking water is critical for evaluation of confining-bed integ...

  7. The influence of complex biological feedstock on the fluidization and bed stability in expanded bed adsorption

    PubMed

    Fernandez-Lahore; Kleef; Kula; Thommes

    1999-08-20

    The stability of expanded bed adsorption systems (EBA) was studied in biomass containing culture broth by residence time distribution (RTD) experiments, using pulse inputs of fluorescent molecules as tracers. Different commercial adsorbents (Streamline DEAE, SP, Phenyl, Chelating, and AC) were tested at various biomass concentrations (2.5-12 %, wet weight) of whole (Saccharomyces cerevisiae) yeast, yeast cell homogenate, and Escherichia coli homogenate. Analyzing the RTD according to the PDE model (PDE: axially dispersed plug-flow exchanging mass with stagnant zones) allowed the calculation of three parameters: the number of transfer units for mass exchange between mobile and stagnant fraction (N), the Peclet number for overall axial dispersion (P), and the mobile fraction of the liquid in axially dispersed plug flow (varphi). When fluidization was performed in particle-free buffer the normalized response signal (after perfect input pulse) was symmetric (N:0; P: 50-100; varphi: 1), thus, demonstrating the formation of a homogeneous fluidized (expanded) bed. Upon application of suspended biomass the RTD was skewed, depending on the adsorbent used and the type and level of biomass present in the sample. This situation leads to three different characteristic pictures: the well-fluidized system (N: >/= 7-10; P: >/= 40; varphi: 0.80-0.90), the system exhibiting bottom channeling (N: < 1-2; P: >/= 40; varphi: 0.5-0.7) and, the system where extensive agglomeration develops (N: 4-7; P: 20-40; varphi: < 0.5). These results demonstrate that changes in the hydrodynamics of EBA already take place in the presence of moderate concentrations of biomass. Furthermore, those changes can be quantitatively described mainly in terms of the fraction of stagnant zones in the system, which are formed due to the interaction of biomass and adsorbent. The technique described here can be used to evaluate a certain combination of adsorbent and biomass with regard to its suitability for

  8. Videos, Webinars, Blogs Related to Bed Bugs

    EPA Pesticide Factsheets

    These tools provide practical insight on issues such as integrated pest management (IPM) for schools, bed bug bites, how carpet beetles can help, bed bugs as hitchhikers, and preventing and controlling infestations.

  9. Pulling a patient up in bed

    MedlinePlus

    Moving a patient in bed ... takes at least 2 people to safely move a patient up in bed. Friction from rubbing can ... A slide sheet is the best way to prevent friction. If you do not have one, you ...

  10. Find a Bed Bug Pesticide Product

    EPA Pesticide Factsheets

    Introduces the Bed Bug Product Search Tool, to help consumers find EPA-registered pesticides for bed bug infestation control. Inclusion in this database is not an endorsement. Always follow label directions carefully.

  11. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    EPA Science Inventory

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  12. Bed Bug Guidance for School Nurses

    EPA Pesticide Factsheets

    School nurses are often called upon to provide vital information to students, parents, teachers, and administrators. These tips on identifying, managing and preventing bed bugs will help you to effectively respond if bed bugs appear in your school.

  13. Bacillus cereus in free-stall bedding.

    PubMed

    Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

    2007-12-01

    To increase the understanding of how different factors affect the bacterial growth in deep sawdust beds for dairy cattle, the microbiological status of Bacillus cereus and coliforms in deep sawdust-bedded free stalls was investigated over two 14-d periods on one farm. High counts of B. cereus and coliforms were found in the entire beds. On average, 4.1 log(10) B. cereus spores, 5.5 log(10) B. cereus, and 6.7 log(10) coliforms per gram of bedding could be found in the upper layers of the sawdust likely to be in contact with the cows' udders. The highest counts of B. cereus spores, B. cereus, and coliforms were found in the bedding before fresh bedding was added, and the lowest immediately afterwards. Different factors of importance for the growth of B. cereus in the bedding material were explored in laboratory tests. These were found to be the type of bedding, pH, and the type and availability of nutrients. Alternative bedding material such as peat and mixtures of peat and sawdust inhibited the bacterial growth of B. cereus. The extent of growth of B. cereus in the sawdust was increased in a dose-dependent manner by the availability of feces. Urine added to different bedding material raised the pH and also led to bacterial growth of B. cereus in the peat. In sawdust, a dry matter content greater than 70% was needed to lower the water activity to 0.95, which is needed to inhibit the growth of B. cereus. In an attempt to reduce the bacterial growth of B. cereus and coliforms in deep sawdust beds on the farm, the effect of giving bedding daily or a full replacement of the beds was studied. The spore count of B. cereus in the back part of the free stalls before fresh bedding was added was 0.9 log units lower in stalls given daily bedding than in stalls given bedding twice weekly. No effect on coliform counts was found. Replacement of the entire sawdust bedding had an effect for a short period, but by 1 to 2 mo after replacement, the counts of B. cereus spores in the

  14. Two-stage fixed-bed gasifier with selectable middle gas off-take point

    DOEpatents

    Strickland, Larry D.; Bissett, Larry A.

    1992-01-01

    A two-stage fixed bed coal gasifier wherein an annular region is in registry with a gasification zone underlying a devolatilization zone for extracting a side stream of high temperature substantially tar-free gas from the gasifier. A vertically displaceable skirt means is positioned within the gasifier to define the lower portion of the annular region so that vertical displacement of the skirt means positions the inlet into the annular region in a selected location within or in close proximity to the gasification zone for providing a positive control over the composition of the side stream gas.

  15. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C.S.; Hawk, J.A.

    1995-07-25

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence. 9 figs.

  16. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence.

  17. Bed Bug Education for School Maintenance

    ERIC Educational Resources Information Center

    Henriksen, Missy

    2012-01-01

    Bed bugs are a growing problem, not only in homes and hotels, but also in schools and colleges. Facility administrators and staff need to understand the bed bug resurgence and develop best practices to deal with an infestation. In this article, the author offers tips for preventing and treating bed bugs in school and university settings.

  18. Characteristics of fluidized-packed beds

    NASA Technical Reports Server (NTRS)

    Gabor, J. D.; Mecham, W. J.

    1968-01-01

    Study of fluidized-packed bed includes investigation of heat transfer, solids-gas mixing, and elutriation characteristics. A fluidized-packed bed is a system involving the fluidization of small particles in the voids of a packed bed of larger nonfluidized particles.

  19. Oxygen consumption along bed forms under losing and gaining streamflow conditions

    NASA Astrophysics Data System (ADS)

    De Falco, Natalie; Arnon, Shai; Boano, Fulvio

    2016-04-01

    Recent studies have demonstrated that bed forms are the most significant geomorphological structure that drives hyporheic exchange and biogeochemical processes in stream networks. Other studies also demonstrated that due to the hyporheic flow patterns within bed form, biogeochemical processes do not occur uniformly along and within the bed forms. The objective of this work was to systematically evaluate how losing or gaining flow conditions affect oxygen consumption by biofilm along sandy bed forms. We measured the effects of losing and gaining flow conditions on oxygen consumption by combining modeling and experiments in a novel laboratory flume system that enable the control of losing and gaining fluxes. Oxygen consumption was measured after growing a benthic biofilm fed with Sodium Benzoate (as a carbon source) and measuring the distribution of oxygen in the streambed with microelectrodes. The experimental results were analyzed using a novel code that calculates vertical profiles of reaction rates in the presence of hyporheic water fluxes. These experimental observations and modeling revealed that oxygen distribution varied along the bed forms. The zone of oxygen consumption (i.e. depth of penetration) was the largest at the upstream side of the bed form and the smallest in the lee side (at the lowest part of the bed form), regardless of the flow conditions. Also, the zone of oxygen consumption was the largest under losing conditions, the smallest under gaining conditions, and in-between under neutral conditions. The distribution of oxygen consumption rates determined with our new model will be also discussed. Our preliminary results enable us to show the importance of the coupling between flow conditions and oxygen consumption along bed forms and are expected to improve our understanding of nutrient cycling in streams.

  20. Lignite air-steam gasification in the fluidized bed of iron-containing slag catalysts

    SciTech Connect

    Kuznetsov, B.N.; Shchipko, M.L.; Golovin, Yu.

    1995-12-01

    The influence of fluidized bed of iron-containing slag particles on air-steam gasification of powdered Kansk-Achinsk lignite in entrained flow was studied in pilot installation with productivity about 60 kg per hour. Slag of Martin process and boiler slag were used as catalytic active materials until their complete mechanical attrition. Two following methods of catalytic gasification of lignite were compared: the partial gasification in stationary fluidized bed of slag particles with degree of fuel conversion 40-70% and complete gasification in circulating bed of slag particles. In the first case only the most reactive part of fuel is gasified with the simultaneously formation of porous carbon residue with good sorption ability. It was found the catalytic fluidized bed improves heat transfer from combustion to reduction zone of gas-generator and increases the rate of fuel conversion at the temperature range 900-1000{degrees}C. At these temperatures the degree of conversion is depended considerably on the duration time of fuel particles in the catalytic fluidized bed. The influence of catalytic fluidized bed height and velocity of reaction mixture on the temperature profiles in the gas-generator was studied. The optimal relationship was found between the fluidized bed height and velocity of flow which makes possible to produce the gas with higher calorific value at maximum degree of fuel conversion.

  1. Experimental study of large-scale pulsations of a fluidized bed

    SciTech Connect

    Glinskii, V.A.; Protod'yakonov, I.O.; Chesnokov, Yu.G.

    1980-01-01

    In experimental investigations of the hydrodynamics of fluidized beds, study of large- and small-scale pulsations of the most important characteristics of the fluidized bed: voidage, hydraulic resistance, velocities of the gaseous and solid phases, etc., is of considerable interest. The character of these pulsations is determined by the heterogeneity of the structure of the fluidized bed, due to the presence of channels, bubbles, stagnant zones, and circulation currents. The object of the present work was experimental study of fluctuations of the height h of the surface of a fluidized bed, with simultaneous recording of the corresponding fluctuations of the hydraulic resistance ..delta..P of the bed. The existence of a direct connection between large-scale pulsations of the hydraulic resistance ..delta..P of the fluidized bed and large-scale pulsations of the bed height h is demonstrated in the paper. It is proved on this basis that large-scale pulsations of h and ..delta..P can be described by equations of the same type. The coefficients of the equation are determined from experimental data on pulsations, and its solutions for different fluidization regimes are analyzed.

  2. Providing plastic zone extrusion

    DOEpatents

    Manchiraju, Venkata Kiran; Feng, Zhili; David, Stan A.; Yu, Zhenzhen

    2017-04-11

    Plastic zone extrusion may be provided. First, a compressor may generate frictional heat in stock to place the stock in a plastic zone of the stock. Then, a conveyer may receive the stock in its plastic zone from the compressor and transport the stock in its plastic zone from the compressor. Next, a die may receive the stock in its plastic zone from the conveyer and extrude the stock to form a wire.

  3. Laboratory and In Situ Simulation Tests of the Excavation Damaged Zone Around Galleries in Opalinus Clay

    NASA Astrophysics Data System (ADS)

    Labiouse, Vincent; Vietor, Tim

    2014-01-01

    In the context of nuclear waste disposal in clay formations, laboratory and in situ simulation experiments were performed to study at reduced scale the excavation damaged zone (EDZ) around tunnels in the indurated Opalinus Clay at Mont Terri, Switzerland. In the laboratory, thick-walled hollow cylindrical specimens were subjected to a mechanical unloading mimicking a gallery excavation. In samples cored parallel to bedding, cracks sub-parallel to the bedding planes open and lead to a buckling failure in two regions that extend from the borehole in the direction normal to bedding. The behaviour is clearly anisotropic. On the other hand, in experiments performed on specimens cored perpendicular to bedding, there is no indication of failure around the hole and the response of the hollow cylinder sample is mainly isotropic. The in situ experiment at Mont Terri which consisted in the overcoring of a resin-injected borehole that follows the bedding strike of the Opalinus Clay showed a striking similarity between the induced damaged zone and the fracture pattern observed in the hollow cylinder tests on samples cored parallel to bedding and such a bedding controlled "Excavation" Damaged Zone is as well consistent with the distinct fracture patterns observed at Mont Terri depending on the orientation of holes/galleries with respect to the bedding planes. Interestingly, the damaged zone observed in the hollow cylinder tests on samples cored parallel to bedding and in situ around URL galleries is found to develop in reverse directions in Boom Clay (Mol) and in Opalinus Clay (Mont Terri). This most probably results from different failure mechanisms, i.e. shear failure along conjugated planes in the plastic Boom Clay, but bedding plane splitting and buckling in the indurated Opalinus Clay.

  4. Avionics test bed development plan

    NASA Technical Reports Server (NTRS)

    Harris, L. H.; Parks, J. M.; Murdock, C. R.

    1981-01-01

    The plan is for a facility for the early investigation and evaluation of new concepts for the control of large space structures, orbiter attached flex body experiments, and orbiter enhancements. This plan outlines a distributed data processing facility that will utilize the current JSC laboratory resources for the test bed development. The future studies required for implementation, the management system for project control, and the baseline system configuration are described.

  5. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1992-05-01

    During this first quarter, a lab-scale water-cooled pulse combustor was designed, fabricated, and integrated with old pilot-scale PAFBC test systems. Characterization tests on this pulse combustor firing different kinds of fuel -- natural gas, pulverized coal and fine coal -- were conducted (without fluidized bed operation) for the purpose of finalizing PAFBC full-scale design. Steady-state tests were performed. Heat transfer performance and combustion efficiency of a coal-fired pulse combustor were evaluated.

  6. Scaling of pressurized fluidized beds

    SciTech Connect

    Guralnik, S.; Glicksman, L.R.

    1994-10-01

    The project has two primary objectives. The first is to verify a set of hydrodynamic scaling relationships for commercial pressurized fluidized bed combustors (PFBC). The second objective is to investigate solids mixing in pressurized bubbling fluidized beds. American Electric Power`s (AEP) Tidd combined-cycle demonstration plant will provide time-varying pressure drop data to serve as the basis for the scaling verification. The verification will involve demonstrating that a properly scaled cold model and the Tidd PFBC exhibit hydrodynamically similar behavior. An important issue in PFBC design is the spacing of fuel feed ports. The feed spacing is dictated by the fuel distribution and the mixing characteristics within the bed. After completing the scaling verification, the cold model will be used to study the characteristics of PFBCs. A thermal tracer technique will be utilized to study mixing both near the fuel feed region and in the far field. The results allow the coal feed and distributor to be designed for optimal heating.

  7. Rivesville multicell fluidized bed boiler

    SciTech Connect

    Not Available

    1981-03-01

    One objective of the experimental MFB at Rivesville, WV, was the evaluation of alternate feed systems for injecting coal and limestone into a fluidized bed. A continuous, uniform feed flow to the fluid bed is essential in order to maintain stable operations. The feed system originally installed on the MFB was a gravity feed system with an air assist to help overcome the back pressure created by the fluid bed. The system contained belt, vibrating, and rotary feeders which have been proven adequate in other material handling applications. This system, while usable, had several operational and feeding problems during the MFB testing. A major portion of these problems occurred because the coal and limestone feed control points - a belt feeder and rotary feeder, respectively - were pressurized in the air assist system. These control points were not designed for pressurized service. An alternate feed system which could accept feed from the two control points, split the feed into six equal parts and eliminate the problems of the pressurized system was sought. An alternate feed system designed and built by the Fuller Company was installed and tested at the Rivesville facility. Fuller feed systems were installed on the north and south side of C cell at the Rivesville facility. The systems were designed to handle 10,000 lb/hr of coal and limestone apiece. The systems were installed in late 1979 and evaluated from December 1979 to December 1980. During this time period, nearly 1000 h of operating time was accumulated on each system.

  8. Hyporheic Exchange in Gravel-Bed Rivers with Pool-Riffle Morphology: A 3D Model

    NASA Astrophysics Data System (ADS)

    Tonina, D.; Buffington, J. M.

    2004-12-01

    The hyporheic zone is a saturated band of sediment that surrounds river flow and forms a linkage between the river and the aquifer. It is a rich ecotone where benthic, hyporheic, and groundwater species temporarily or permanently reside. Head gradients along the streambed draw river water into the hyporheic zone and expel pore water into the stream. This process, known as hyporheic exchange, is important for delivering nutrients, oxygen and other solutes to the sediment, and for washing away waste products to support this ecotone. It is an essential component of the carbon and nitrogen cycles, and it controls in-stream contaminant transport. Although hyporheic exchange has been studied in sand-bed rivers with two-dimensional dune morphology, few studies have been conducted for gravel-bed rivers with three-dimensional pool-riffle geometry. The hyporheic zone of gravel-bed rivers is particularly important for salmonids, many of which are currently at risk world wide. Salmon and trout lay their eggs within the hyporheic zone for incubation. After hatching, the alevins live in the gravel before emerging into the stream. The upwelling and downwelling hyporheic fluxes are intense in these streams due to the highly permeable sediment and strong head variations forced by shallow flow over high-amplitude bed forms. Moreover, gravel-bed rivers show a wide range of flow regimes that change seasonally and have strong effects on hyporheic exchange. To study this exchange, we used four sets of pool-riffle geometries in twelve recirculating flume experiments. We kept a constant bed-form wavelength, but changed the bed-form amplitude and imposed three discharges, covering a wide range of hydraulic and geometric characteristics. Hyporheic exchange was predicted from a three-dimensional model based on bedform-induced pumping transport, where the boundary head profile is the pressure head distribution at the sediment interface, measured with an array of mini-piezometers buried within

  9. Agglomeration-Free Distributor for Fluidized Beds

    NASA Technical Reports Server (NTRS)

    Ouyang, F.; Sinica, A.; Levenspiel, O.

    1986-01-01

    New gas distributor for fluidized beds prevents hot particles from reacting on it and forming hard crust. In reduction of iron ore in fluidized bed, ore particles do not sinter on distributor and perhaps clog it or otherwise interfere with gas flow. Distributor also relatively cool. In fluidized-bed production of silicon, inflowing silane does not decompose until within bed of hot silicon particles and deposits on them. Plates of spiral distributor arranged to direct incoming gas into spiral flow. Turbulence in flow reduces frequency of contact between fluidized-bed particles and distributor.

  10. Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

    DOEpatents

    Badger, Phillip C.; Dunn, Jr., Kenneth J.

    2015-09-01

    A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

  11. Bed Bug Infestations in an Urban Environment

    PubMed Central

    Svoboda, Tomislav J.; De Jong, Iain J.; Kabasele, Karl J.; Gogosis, Evie

    2005-01-01

    Until recently, bed bugs have been considered uncommon in the industrialized world. This study determined the extent of reemerging bed bug infestations in homeless shelters and other locations in Toronto, Canada. Toronto Public Health documented complaints of bed bug infestations from 46 locations in 2003, most commonly apartments (63%), shelters (15%), and rooming houses (11%). Pest control operators in Toronto (N = 34) reported treating bed bug infestations at 847 locations in 2003, most commonly single-family dwellings (70%), apartments (18%), and shelters (8%). Bed bug infestations were reported at 20 (31%) of 65 homeless shelters. At 1 affected shelter, 4% of residents reported having bed bug bites. Bed bug infestations can have an adverse effect on health and quality of life in the general population, particularly among homeless persons living in shelters. PMID:15829190

  12. Bed bug aggregation pheromone finally identified.

    PubMed

    Gries, Regine; Britton, Robert; Holmes, Michael; Zhai, Huimin; Draper, Jason; Gries, Gerhard

    2015-01-19

    Bed bugs have become a global epidemic and current detection tools are poorly suited for routine surveillance. Despite intense research on bed bug aggregation behavior and the aggregation pheromone, which could be used as a chemical lure, the complete composition of this pheromone has thus far proven elusive. Here, we report that the bed bug aggregation pheromone comprises five volatile components (dimethyl disulfide, dimethyl trisulfide, (E)-2-hexenal, (E)-2-octenal, 2-hexanone), which attract bed bugs to safe shelters, and one less-volatile component (histamine), which causes their arrestment upon contact. In infested premises, a blend of all six components is highly effective at luring bed bugs into traps. The trapping of juvenile and adult bed bugs, with or without recent blood meals, provides strong evidence that this unique pheromone bait could become an effective and inexpensive tool for bed bug detection and potentially their control.

  13. Linear test bed. Volume 1: Test bed no. 1. [aerospike test bed with segmented combustor

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Linear Test Bed program was to design, fabricate, and evaluation test an advanced aerospike test bed which employed the segmented combustor concept. The system is designated as a linear aerospike system and consists of a thrust chamber assembly, a power package, and a thrust frame. It was designed as an experimental system to demonstrate the feasibility of the linear aerospike-segmented combustor concept. The overall dimensions are 120 inches long by 120 inches wide by 96 inches in height. The propellants are liquid oxygen/liquid hydrogen. The system was designed to operate at 1200-psia chamber pressure, at a mixture ratio of 5.5. At the design conditions, the sea level thrust is 200,000 pounds. The complete program including concept selection, design, fabrication, component test, system test, supporting analysis and posttest hardware inspection is described.

  14. Subtidal and intertidal mussel beds ( Mytilus edulis L.) in the Wadden Sea: diversity differences of associated epifauna

    NASA Astrophysics Data System (ADS)

    Saier, Bettina

    2002-04-01

    In 1997 and 1998, surveys were performed to compare species composition, abundance and diversity of non-attached epifauna (>1 mm) in low intertidal and adjacent shallow subtidal zones of three mussel beds ( Mytilus edulis L.) near the island of Sylt in the North Sea. The community structure was similar when compared within tidal zones: no significant differences in species numbers and abundances were recorded between locations and between years. A comparison between tidal zones, however, revealed higher diversity, species densities and total species numbers in the subtidal (per 1,000 cm2: H '=2.0±0.16; 12 ±1 species density; 22 species) than the intertidal zone (per 1,000 cm2: H '=0.7±0.27; 6±2 species density; 19 species). Abundances significantly dropped with increasing submergence from 2,052 (±468) m-2 to 1,184 (±475) m-2. This was mainly due to significantly higher densities of both juvenile periwinkles, Littorina littorea, and crabs, Carcinus maenas, in intertidal mussel beds. However, many less dominant species were significantly more abundant in subtidal mussel beds. This study revealed that in the non-attached epifaunal community of mussel beds the tidal level effect within metres was strong, whilst the spatial variability in a much wider (kilometre) range but the same tidal level was negligible. The high epifaunal diversity in the subtidal zone suggests that the protective measures for mussel beds against the effects of mussel fishery should be extended from the intertidal to the subtidal zone, if the integrity of the mussel bed community in the Wadden Sea National Park is to be maintained.

  15. Origin of Subglacial Debris-bed Friction

    NASA Astrophysics Data System (ADS)

    Cohen, D. O.; Byers, J.; Iverson, N. R.

    2011-12-01

    Numerical models of glaciers sliding on hard beds assume that basal flow resistance is controlled entirely by viscous drag on bedrock bumps. However, observations and measurements indicate that basal ice can contain large concentrations of rock debris that exert significant frictional resistance: for example, locally high shear stress (˜500 kPa) was measured below 200 m of ice on a smooth rock tablet at the bed of Engabreen, Norway. This value of shear stress is an order of magnitude greater than estimated by leading theories. To better understand the origin of debris-bed friction, we built a new laboratory apparatus that recorded the contact force between a clast and a hard bed as a function of ice velocity toward the bed. An independent experiment with the same apparatus in which the clast is isolated from the bed was used to obtain the ice viscosity. After correcting for cavity formation and ice flow geometry, results indicate that the contact force between a clast and a hard bed is about twice the drag force on the same clast estimated using Stokes's law. This value is insufficient to explain the high debris-bed friction measured beneath Engabreen. An alternative explanation is that longitudinal ice extension caused by ice flowing over the rough topography near the smooth rock tablet increased the rate of ice convergence with the bed by a factor of 5. Our measurements confirm that debris-bed friction is controlled by contact forces caused by flow of ice towards the bed due to basal melting and longitudinal ice extension. This form of frictional drag has yet to be included in models of ice flow. Inclusion of debris-bed friction may prove important to properly estimating rates of basal sliding, energy dissipation and meltwater production at the bed, and, more importantly, to quantifying the stick-slip behavior of hard-bedded glaciers.

  16. Distribution of bromine in bedded halite in the Green River Formation, southwestern Wyoming

    USGS Publications Warehouse

    Higley, D.K.

    1983-01-01

    The Wilkins Peak Member of the Eocene Green River Formation of southwestern Wyoming contains a series of halite-trona beds deposited in ancestral Lake Gosiute. X-ray fluorescence analysis of 311) salt samples from 10 core holes revealed bromine contents ranging from 11 to 174 ppm. The average concentration, corrected to 100 percent sodium chloride, is approximately 80 ppm. The bromine content of most halite beds increases from the base upward. Variations or 'spikes' in the bromine profile and reversals of the upward increase in bromine are evidenced within several salt beds. Bromine of bed 10 salt zones exhibits a high degree of correlation laterally. No increase in bromine concentration for correlated salt zones was noted from the basin margins to the depositional center in the northeastern part of the study area. A great disparity in salt thickness from the depositional center to the margins suggests stratified lake conditions in which denser, sodium-chloride-saturated bottom brines did not extend to the margins during part of the depositional history of bed 10. Paleosalinity trends of Lake Gosiute determined from the bromine distribution include the following: (1) chemically stratified lake conditions with dense, highly saline bottom waters and a fresher water zone above during much of the depositional history of the halites, (2) gradual evaporation of lake waters in a closed basin with resultant upward increase in salinity for most intervals studied, and (3) absence of lateral lake-bottom salinity gradients or postdepositional salt alteration as determined by the lateral constancy of bromine concentrations for correlated bed 10 halite.

  17. Phase 2 Methyl Iodide Deep-Bed Adsorption Tests

    SciTech Connect

    Soelberg, Nick; Watson, Tony

    2014-09-01

    Nuclear fission produces fission products (FPs) and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Research, demonstrations, and some reprocessing plant experience have indicated that diatomic iodine can be captured with efficiencies high enough to meet regulatory requirements. Research on the capture of organic iodides has also been performed, but to a lesser extent. Several questions remain open regarding the capture of iodine bound in organic compounds. Deep-bed methyl iodide adsorption testing has progressed according to a multi-laboratory methyl iodide adsorption test plan. This report summarizes the second phase of methyl iodide adsorption work performed according to this test plan using the deep-bed iodine adsorption test system at the Idaho National Laboratory (INL), performed during the second half of Fiscal Year (FY) 2014. Test results continue to show that methyl iodide adsorption using AgZ can achieve total iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) above 1,000, until breakthrough occurred. However, mass transfer zone depths are deeper for methyl iodide adsorption compared to diatomic iodine (I2) adsorption. Methyl iodide DFs for the Ag Aerogel test adsorption efficiencies were less than 1,000, and the methyl iodide mass transfer zone depth exceeded 8 inches. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption under various conditions specified in the methyl iodide test plan, and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  18. Deep Bed Iodine Sorbent Testing FY 2011 Report

    SciTech Connect

    Nick Soelberg; Tony Watson

    2011-08-01

    Nuclear fission results in the production of fission products (FPs) and activation products that increasingly interfere with the fission process as their concentrations increase. Some of these fission and activation products tend to evolve in gaseous species during used nuclear fuel reprocessing. Analyses have shown that I129, due to its radioactivity, high potential mobility in the environment, and high longevity (half life of 15.7 million years), can require control efficiencies of up to 1,000x or higher to meet regulatory emission limits. Deep-bed iodine sorption testing has been done to evaluate the performance of solid sorbents for capturing iodine in off-gas streams from nuclear fuel reprocessing plants. The objectives of the FY 2011 deep bed iodine sorbent testing are: (1) Evaluate sorbents for iodine capture under various conditions of gas compositions and operating temperature (determine sorption efficiencies, capacities, and mass transfer zone depths); and (2) Generate data for dynamic iodine sorption modeling. Three tests performed this fiscal year on silver zeolite light phase (AgZ-LP) sorbent are reported here. Additional tests are still in progress and can be reported in a revision of this report or a future report. Testing was somewhat delayed and limited this year due to initial activities to address some questions of prior testing, and due to a period of maintenance for the on-line GC. Each test consisted of (a) flowing a synthetic blend of gases designed to be similar to an aqueous dissolver off-gas stream over the sorbent contained in three separate bed segments in series, (b) measuring each bed inlet and outlet gas concentrations of iodine and methyl iodide (the two surrogates of iodine gas species considered most representative of iodine species expected in dissolver off-gas), (c) operating for a long enough time to achieve breakthrough of the iodine species from at least one (preferably the first two) bed segments, and (d) post-test purging

  19. The Berlin emissivity database (BED)

    NASA Astrophysics Data System (ADS)

    Maturilli, A.; Helbert, J.; Moroz, L.

    2008-03-01

    Remote-sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to the solar system bodies include in their payload, instruments measuring the emerging radiation in the infrared range. Apart from measuring the reflected radiance, more and more spacecrafts are equipped with instruments measuring directly the emitted radiation from the planetary surface. The emitted radiation is not only a function of the composition of the material but also of its texture and especially the grain size distribution. For the interpretation of the measured data an emissivity spectral library of planetary analogue materials in grain size fractions appropriate for planetary surfaces is needed. The Berlin emissivity database (BED) presented here is focused on relatively fine-grained size separates, providing thereby a realistic basis for the interpretation of thermal emission spectra of planetary regoliths. The BED is therefore complimentary to existing thermal emission libraries, like the ASU library for example. BED currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulfur, Martian analogue minerals and volcanic soils, and a lunar highland soil sample measured in the wavelength range from 7 to 22 μm as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from <25 to 250 μm. The device we used is built at DLR (Berlin) and is coupled to a Fourier-transform infrared spectrometer Bruker IFS 88 purged with dry air and equipped with a nitrogen-cooled MCT detector. All spectra were acquired with a spectral resolution of 4 cm -1. We are currently working on upgrading our emissivity facility. A new spectrometer (Bruker VERTEX 80 V) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 μm in a vacuum environment. This will be

  20. Fluidized bed charcoal particle production system

    SciTech Connect

    Sowards, N.K.

    1985-04-09

    A fluidized bed charcoal particle production system, including apparatus and method, wherein pieces of combustible waste, such as sawdust, fragments of wood, etc., are continuously disposed within a fluidized bed of a pyrolytic vessel. Preferably, the fluidized bed is caused to reach operating temperatures by use of an external pre-heater. The fluidized bed is situated above an air delivery system at the bottom of the vessel, which supports pyrolysis within the fluidized bed. Charcoal particles are thus formed within the bed from the combustible waste and are lifted from the bed and placed in suspension above the bed by forced air passing upwardly through the bed. The suspended charcoal particles and the gaseous medium in which the particles are suspended are displaced from the vessel into a cyclone mechanism where the charcoal particles are separated. The separated charcoal particles are quenched with water to terminate all further charcoal oxidation. The remaining off-gas is burned and, preferably, the heat therefrom used to generate steam, kiln dry lumber, etc. Preferably, the bed material is continuously recirculated and purified by removing tramp material.

  1. Advanced expander test bed engine

    NASA Technical Reports Server (NTRS)

    Mitchell, J. P.

    1992-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high pressure expander cycle concept, study system interactions, and conduct studies of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  2. Advanced expander test bed program

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Mitchell, J. C.

    1991-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Chemical Transfer Propulsion Program for development and demonstration of expander cycle oxygen/hydrogen engine technology component technology for the next space engine. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced missions focused components and new health monitoring techniques. The split-expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  3. MICROTURBULENCE IN GRAVEL BED STREAMS

    NASA Astrophysics Data System (ADS)

    Papanicolaou, T.; Tsakiris, A. G.; Kramer, C. M.

    2009-12-01

    The overarching objective of this investigation was to evaluate the role of relative submergence on the formation and evolution of cluster microforms in gravel bed streams and its implications to bedload transport. Secondary objectives of this research included (1) a detailed analysis of mean flow measurements around a clast; and (2) a selected number of experimental runs where the mean flow characteristics are linked together with the bed micro-topography observations around a clast. It is hypothesized that the relative submergence is an important parameter in defining the feedback processes between the flow and clasts, which governs the flow patterns around the clasts, thus directly affecting the depositional patterns of the incoming sediments. To examine the validity of the hypothesis and meet the objectives of this research, 19 detailed experimental runs were conducted in a tilting, water recirculating laboratory flume under well-controlled conditions. A fixed array of clast-obstacles were placed atop a well-packed bed with uniform size glass beads. During the runs, multifractional spherical particles were fed upstream of the clast section at a predetermined rate. State-of-the-art techniques/instruments, such as imaging analysis software, Large Scale Particle Velocimeter (LSPIV) and an Acoustic Doppler Velocimetry (ADV) were employed to provide unique quantitative measurements for bedload fluxes, clast/clusters geomorphic patterns, and mean flow characteristics in the vicinity of the clusters. Different flow patterns were recorded for the high relative submergence (HRS) and low relative submergence (LRS) experimental runs. The ADV measurements provided improved insight about the governing flow mechanisms for the HRS runs. These mechanisms were described with flow upwelling at the center of the flume and downwelling occurring along the flume walls. Flow downwelling corresponded to an increase in the free surface velocity. Additionally, the visual observations

  4. Pressurized fluidized-bed combustion

    SciTech Connect

    Not Available

    1980-10-01

    The US DOE pressurized fluidized bed combustion (PFBC) research and development program is designed to develop the technology and data base required for the successful commercialization of the PFBC concept. A cooperative program with the US, West Germany, and the UK has resulted in the construction of the 25 MWe IEA-Grimethorpe combined-cycle pilot plant in England which will be tested in 1981. A 13 MWe coal-fired gas turbine (air cycle) at Curtis-Wright has been designed and construction scheduled. Start-up is planned to begin in early 1983. A 75 MWe pilot plant is planned for completion in 1986. Each of these PFBC combined-cycle programs is discussed. The current status of PFB technology may be summarized as follows: turbine erosion tolerance/hot gas cleanup issues have emerged as the barrier technology issues; promising turbine corrosion-resistant materials have been identified, but long-term exposure data is lacking; first-generation PFB combustor technology development is maturing at the PDU level; however, scale-up to larger size has not been demonstrated; and in-bed heat exchanger materials have been identified, but long-term exposure data is lacking. The DOE-PFB development plan is directed at the resolution of these key technical issues. (LCL)

  5. Physiology of prolonged bed rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1988-01-01

    Bed rest has been a normal procedure used by physicians for centuries in the treatment of injury and disease. Exposure of patients to prolonged bed rest in the horizontal position induces adaptive deconditioning responses. While deconditioning responses are appropriate for patients or test subjects in the horizontal position, they usually result in adverse physiological responses (fainting, muscular weakness) when the patient assume the upright posture. These deconditioning responses result from reduction in hydrostatic pressure within the cardiovascular system, virtual elimination of longitudinal pressure on the long bones, some decrease in total body metabolism, changes in diet, and perhaps psychological impact from the different environment. Almost every system in the body is affected. An early stimulus is the cephalic shift of fluid from the legs which increases atrial pressure and induces compensatory responses for fluid and electrolyte redistribution. Without countermeasures, deterioration in strength and muscle function occurs within 1 wk while increased calcium loss may continue for months. Research should also focus on drug and carbohydrate metabolism.

  6. Suicide following an infestation of bed bugs

    PubMed Central

    Burrows, Stephanie; Perron, Stéphane; Susser, Stephanie

    2013-01-01

    Patient: Male, 62 Final Diagnosis: Bipolar disorder Symptoms: Bordeline personality disorder Medication: — Clinical Procedure: Bed bug infestation Specialty: Psychiatry Objective: Unusual clinical course Background: In the past decade, bed bug infestations have been increasingly common in high income countries. Psychological consequences of these infestations are rarely examined in the scientific literature. Case Report: We present a case, based on a coroner’s investigation report, of a woman with previous psychiatric morbidity who jumped to her death following repeated bed bug infestations in her apartment. Our case report shows that the bed bug infestations were the likely trigger for the onset a negative psychological state that ultimately led to suicide. Conclusions: Given the recent surge in infestations, rapid action needs to be taken not only in an attempt to control and eradicate the bed bugs but also to adequately care for those infested by bed bugs. PMID:23826461

  7. Classifying bed inclination using pressure images.

    PubMed

    Baran Pouyan, M; Ostadabbas, S; Nourani, M; Pompeo, M

    2014-01-01

    Pressure ulcer is one of the most prevalent problems for bed-bound patients in hospitals and nursing homes. Pressure ulcers are painful for patients and costly for healthcare systems. Accurate in-bed posture analysis can significantly help in preventing pressure ulcers. Specifically, bed inclination (back angle) is a factor contributing to pressure ulcer development. In this paper, an efficient methodology is proposed to classify bed inclination. Our approach uses pressure values collected from a commercial pressure mat system. Then, by applying a number of image processing and machine learning techniques, the approximate degree of bed is estimated and classified. The proposed algorithm was tested on 15 subjects with various sizes and weights. The experimental results indicate that our method predicts bed inclination in three classes with 80.3% average accuracy.

  8. Volcanic ash dispersed in the Wyodak-Anderson coal bed, Powder River Basin, Wyoming

    USGS Publications Warehouse

    Triplehorn, D.M.; Stanton, R.W.; Ruppert, L.F.; Crowley, S.S.

    1991-01-01

    Minerals derived from air-fall volcanic ash were found in two zones in the upper Paleocene Wyodak-Anderson coal bed of the Fort Union Formation in the Powder River Basin of Wyoming, and are the first reported evidence of such volcanic material in this thick (> 20 m) coal bed. The volcanic minerals occur in zones that are not visually obvious because they contain little or no clay. These zones were located by geophysical logs of the boreholes and X-ray radiography of the cores. The zones correspond to two of a series of incremental core samples of the coal bed that have anomalous concentrations of Zr, Ba, Nb, Sr, and P2O5. Two suites of minerals were found in both of the high-density zones. A primary suite (not authigenic) consists of silt-sized quartz grains, biotite, and minor zircon. A minor suite consists of authigenic minerals, including calcite, pyrite, kaolinite, quartz, anatase, barite, and an alumino-phosphate (crandallite?). The original volcanic ash is inferred to have consisted of silica glass containing phenocrysts of quartz, biotite, zircon, and possibly, associated feldspars, pyroxenes, and amphiboles. The glass, as well as the less stable minerals, probably dissolved relatively quickly and contributed to the minor authigenic mineral suite or was removed from the peat as a result of the prevailing hydrologic conditions present in a raised peat formation. This type of volcanic ash suggests that suggests that volcanic material could have rained on the peat; this fallout may have also had a fertilizing effect on the peat by providing nutrients essential for plant growth thus contributing to the thick accumulations of the Wyodak-Anderson bed. Notwithstanding, the presence of these minerals provides evidence for the contribution by volcanic sources to the mineral content of coal, but not as tonsteins. ?? 1991.

  9. Evaluation of a clay-based acidic bedding conditioner for dairy cattle bedding.

    PubMed

    Proietto, R L; Hinckley, L S; Fox, L K; Andrew, S M

    2013-02-01

    This study investigated the effects of a clay-based acidic bedding conditioner on sawdust bedding pH, dry matter (DM), environmental pathogen counts, and environmental bacterial counts on teat ends of lactating dairy cows. Sixteen lactating Holstein cows were paired based on parity, days in milk, milk yield, and milk somatic cell count, and were negative for the presence of an intramammary pathogen. Within each pair, cows were randomly assigned to 1 of 2 treatments with 3-wk periods in a crossover design. Treatment groups consisted of 9 freestalls per group bedded with either untreated sawdust or sawdust with a clay-based acidic bedding conditioner, added at 3- to 4-d intervals over each 21-d period. Bedding and teat ends were aseptically sampled on d 0, 1, 2, 7, 14, and 21 for determination of environmental bacterial counts. At the same time points, bedding was sampled for DM and pH determination. The bacteria identified in the bedding material were total gram-negative bacteria, Streptococcus spp., and coliform bacteria. The bacteria identified on the teat ends were Streptococcus spp., coliform bacteria, and Klebsiella spp. Teat end score, milk somatic cell count, and intramammary pathogen presence were measured weekly. Bedding and teat cleanliness, environmental high and low temperatures, and dew point data were collected daily. The bedding conditioner reduced the pH, but not the DM, of the sawdust bedding compared with untreated sawdust. Overall environmental bacterial counts in bedding were lower for treated sawdust. Total bacterial counts in bedding and on teat ends increased with time over both periods. Compared with untreated sawdust, the treated bedding had lower counts of total gram-negative bacteria and streptococci, but not coliform counts. Teat end bacterial counts were lower for cows bedded on treated sawdust for streptococci, coliforms, and Klebsiella spp. compared with cows bedded on untreated sawdust. The clay-based acidic bedding conditioner

  10. Solar energy assisted fluidized bed fruit drying

    NASA Astrophysics Data System (ADS)

    Kilkis, B.

    The possibility of using the fluidized-bed principle for solar drying of fruits economically and simply is explored. With the aid of computerized design methods, an optimized fluidized bed/packed bed combination was achieved, that in addition functions as a solar air heater. Based on this configuration, a novel aparatus was designed in Turkey for drying Turkish grapes. Comparisons with comparable systems are made.

  11. Fluidized Bed Boiler Assessment for Navy Applications

    DTIC Science & Technology

    1986-11-01

    inertia and latent heat stored in the bed material allow newly added fuel to ignite quickly and evenly; even wet or low-quality fuels can be burned...about 97% inert bed material (e.g., sand) and 3% fuel. The upper bed is composed of finely ground sulfur sorbent and is where desulfurization of...can be burned without the need of the expensive back-end desulfurization equipment. In fact, most FBC boilers can practically burn all combustible

  12. Fuel bed characteristics of Sierra Nevada conifers

    USGS Publications Warehouse

    van Wagtendonk, J.W.; Benedict, J.M.; Sydoriak, W.M.

    1998-01-01

    A study of fuels in Sierra Nevada conifer forests showed that fuel bed depth and fuel bed weight significantly varied by tree species and developmental stage of the overstory. Specific values for depth and weight of woody, litter, and duff fuels are reported. There was a significant positive relationship between fuel bed depth and weight. Estimates of woody fuel weight using the planar intercept method were significantly related to sampled values. These relationships can be used to estimate fuel weights in the field.

  13. Battery using a metal particle bed electrode

    SciTech Connect

    Evans, James V.; Savaskan, Gultekin

    1991-01-01

    A zinc-air battery in a case including a zinc particle bed supported adjacent the current feeder and diaphragm on a porous support plate which holds the particles but passes electrolyte solution. Electrolyte is recycled through a conduit between the support plate and top of the bed by convective forces created by a density of differential caused by a higher concentration of high density discharge products in the interstices of the bed than in the electrolyte recycle conduit.

  14. Battery using a metal particle bed electrode

    SciTech Connect

    Evans, J.V.; Savaskan, G.

    1991-04-09

    A zinc-air battery in a case is described including a zinc particle bed supported adjacent the current feeder and diaphragm on a porous support plate which holds the particles but passes electrolyte solution. Electrolyte is recycled through a conduit between the support plate and top of the bed by convective forces created by a density of differential caused by a higher concentration of high density discharge products in the interstices of the bed than in the electrolyte recycle conduit. 7 figures.

  15. Updraft Fixed Bed Gasification Aspen Plus Model

    SciTech Connect

    2007-09-27

    The updraft fixed bed gasification model provides predictive modeling capabilities for updraft fixed bed gasifiers, when devolatilization data is available. The fixed bed model is constructed using Aspen Plus, process modeling software, coupled with a FORTRAN user kinetic subroutine. Current updraft gasification models created in Aspen Plus have limited predictive capabilities and must be "tuned" to reflect a generalized gas composition as specified in literature or by the gasifier manufacturer. This limits the applicability of the process model.

  16. Gas distributor for fluidized bed coal gasifier

    DOEpatents

    Worley, Arthur C.; Zboray, James A.

    1980-01-01

    A gas distributor for distributing high temperature reaction gases to a fluidized bed of coal particles in a coal gasification process. The distributor includes a pipe with a refractory reinforced lining and a plurality of openings in the lining through which gas is fed into the bed. These feed openings have an expanding tapered shape in the downstream or exhaust direction which aids in reducing the velocity of the gas jets as they enter the bed.

  17. Combined fluidized bed retort and combustor

    DOEpatents

    Shang, Jer-Yu; Notestein, John E.; Mei, Joseph S.; Zeng, Li-Wen

    1984-01-01

    The present invention is directed to a combined fluidized bed retorting and combustion system particularly useful for extracting energy values from oil shale. The oil-shale retort and combustor are disposed side-by-side and in registry with one another through passageways in a partition therebetween. The passageways in the partition are submerged below the top of the respective fluid beds to preclude admixing or the product gases from the two chambers. The solid oil shale or bed material is transported through the chambers by inclining or slanting the fluidizing medium distributor so that the solid bed material, when fluidized, moves in the direction of the downward slope of the distributor.

  18. Packed fluidized bed blanket for fusion reactor

    DOEpatents

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  19. Conceptual design of ECLSS microgravity test beds

    NASA Technical Reports Server (NTRS)

    Kolodney, Matt; Dall-Bauman, Liese

    1992-01-01

    Conceptual designs were prepared for Space Station Freedom ECLSS test beds for both the Air Revitalization Subsystem (ARS) and the Water Recovery and Management Subsystem (WRMS), which will allow extended testing of equipment under microgravity conditions. The separate designs for the ARS and the WRMS include storage tanks, plumbing, and limited instrumentation that would be expected to be common to all air or water treatment equipment of interest. The beds are designed to recycle process fluids to the greatest extent possible, thus minimizing the spacecraft/test bed interface requirements. Schematic diagrams of both the ARS and the WRMS test beds are included.

  20. Fluidized bed regenerators for Brayton cycles

    NASA Technical Reports Server (NTRS)

    Nichols, L. D.

    1975-01-01

    A recuperator consisting of two fluidized bed regenerators with circulating solid particles is considered for use in a Brayton cycle. These fluidized beds offer the possibility of high temperature operation if ceramic particles are used. Calculations of the efficiency and size of fluidized bed regenerators for typical values of operating parameters were made and compared to a shell and tube recuperator. The calculations indicate that the fluidized beds will be more compact than the shell and tube as well as offering a high temperature operating capability.

  1. Backfill-simulated moving bed operation for improving the separation performance of simulated moving bed chromatography.

    PubMed

    Kim, Kyung-Min; Lee, Chang-Ha

    2013-10-11

    The Backfill-SMB (BF-SMB) strategy was designed to improve the separation performance of simulated moving bed (SMB) chromatography. In the BF-SMB operation, a limited amount of products from raffinate and/or extract was re-fed to the SMB circuit as a backfill-feed. Two additional operating variables, backfill ratio (BR) and backfill length (BL), were suggested to determine the amount and injection length of backfill-feed. This strategy was applied to a four-zone SMB with one column (1-1-1-1) and two columns (2-2-2-2) per zone using a binary mixture with a nonlinear isotherm. Various BF-SMB operational methods were designed to supply backfill-feed to the feed node and/or intermediate node. The separation performances of conventional SMB and BF-SMB were compared in terms of purity, recovery, and eluent consumption. The BF-SMB successfully improved the separation performance of the conventional SMB because backfill-feed led to the rich condition of the main component at each product withdrawal node. Due to the 'TMB effect' caused by backfill-feed, the BF-SMB operation was more efficient in the 1-1-1-1 configuration than in the 2-2-2-2 configuration, showing maximum improvement of 5-7% purity and recovery from the performance of conventional SMB. In addition, partial recycling of eluent by backfill-feed resulted in a decrease in eluent consumption up to 10% even with improved purity and recovery in BF-SMB.

  2. CERTS Microgrid Laboratory Test Bed

    SciTech Connect

    Eto, Joe; Lasseter, Robert; Schenkman, Ben; Stevens, John; Klapp, Dave; Volkommer, Harry; Linton, Ed; Hurtado, Hector; Roy, Jean

    2009-06-18

    The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2) an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3) a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources. These techniques were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations,and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults. The results from these tests are expected to lead to additional testing of enhancements to the basic techniques at the test bed to improve the business case for microgrid technologies, as well to field demonstrations

  3. Different bed surface and flow resistance characteristics for gravel and sand bed

    NASA Astrophysics Data System (ADS)

    Fan, N.; Yang, K.; Nie, R.; Liu, X.

    2014-12-01

    Bed forms affect both bed load transport and flow resistance strongly and change their shapes and sizes depending on underlying grain size distribution and shear stress. A series of flume experiments were conducted at the Saint Anthony Falls Laboratory to study the effect of bed form dynamics on flow turbulence and sediment transport with both gravel and sand as bed material and different flow conditions. From the experimental data, the spectrum of bed elevation time series, the PDFs of bed elevation increments and the flow resistance characteristics are all analyzed. The wavelet-based spectral analysis shows that the slopes of the elevation spectrums are -2 and -3 for gravel and sand bed surfaces, respectively. The slope -3 indicates that the surface is self-similar, in another words, the ratios of bed form heights and lengths for different bed forms are the same; however, the slope of -2 indicates that the surface is self-affine, and in such case (-2) the ratios of bed form heights and lengths for different bed forms are not correlated at all. We interpret that the relative size of grain and boundary layer affects the bed form characteristics significantly, e.g., grain size of sand is of the same scale as the thickness of boundary layer, but both are much smaller than the grain size of gravel. Our results suggest that the PDFs of bed elevation increments for both gravel and sand beds can be fitted well with two-sided asymmetric exponential function. Furthermore, we show that the flow resistance (Darcy-Weisbach coefficients f) are much higher for sand bed than gravel bed, and the former is contributed by form drags, which is much larger than grain drags. For gravel bed, f and the skewness of bed elevation increments increases with flow discharge whereas for the sand bed, both f and the skewness of bed elevation increments decreases which corresponds to the transition in hydraulic conditions for dune to dynamic flat surface in our experiments. The analysis

  4. Bed aggradation in the lower reach of the Jia Dhansiri River, India

    NASA Astrophysics Data System (ADS)

    Sarmah, Rana

    2012-03-01

    This study aims at estimating the rate of bed aggradation of the Jia Dhansiri River in Assam, India. It is carried out using two methods: (1) measurement of channel cross section in the field, and (2) measurement of variously dated maps for the period 1995-2006. Following these two methods, data on parameters pertaining to bed aggradation are generated and authenticated by comparison. Data on total bed aggradation during 1995-2006 are extrapolated from cross section graphs and again verified with a model proposed in this paper based on average water level of base year and current year and total bed aggradation. The rates of bed aggradations are 5.27 cm/y at Dhansiri Khuti village, 5.09 cm/y at Barigain village, 5.27 cm/y at Bagishakash village, and 2.64 cm/y at Thalthali village. No degradation zones are found in between during the study period except in minor magnitude and localized cases. If these rates of bed aggradation are continued and no significant changes in the channel morphology occur, then the river bed may merge with the low river bank after 11 years at Dhansiri Khuti village, 17 years at Barigaon village, 6 years at Bagishakash village, and 7 years at Thalthali village. The average channel aggradation during 11-years of period in the 16-km reach has estimated to be 3.65 cm/y. Again, if this rate is continued then the river bed will overtop low banks of the 16-km reach after 16 years. At this situation the river may attain a state of geomorphic threshold which may be channel shift following vulnerable slope(s).

  5. Flue gas desulfurization by rotating beds

    SciTech Connect

    Gardner, N.; Keyvani, M.; Coskundeniz, A.

    1992-01-01

    The operating and mass transfer characteristics of rotating foam metal beds were studied to determine the potential for flue gas desulfurization. This is a final technical report on the work supported by DOE [number sign]FG22-87-PC79924. The report is divided into two sections, Part 1 deals primarily with the operating characteristics of rotating beds, and Part 2 covers the mass transfer characteristics of S0[sub 2] absorption in water-lime slurries. Rotating foam metal beds are in essence packed towers operated in high gravitational fields. The foam metal bed is in the form of a cylindrical donut, or torus, and is rotated to produced the high centrifugal forces. The liquid phase enters the bed at the inner surface of the torus and is pulled by the field through the bed. Gas flows countercurrent to the liquid. The bed packing can have a very large specific surface areas and not flood. Possible benefits include much smaller height of a transfer unit resulting in smaller equipment and supporting structures, reduced solvent inventory, faster response with improved process control, reduced pressure drop, and shorter startup and shut-down times. This work is concerned broadly with the operating characteristics of rotating beds, the objectives being to (1) determine the pressure drop through the rotating bed; (2) determine the power required to operate the beds, (3) investigate the residence time distribution of the liquid phase in the beds; and (4) determine the mass transfer coefficients of S0[sub 2] absorption. Three packings of differing specific surface areas were studied, with areas ranging from 656 to 2952 m[sub 2]/m[sub 3]. Liquid flow rates to 36 kg/s*m[sub 2], gas flow rate to 2.2 kg/s*m[sub 2], and gravitational fields to 300 g were covered in this study.

  6. CERTS Microgrid Laboratory Test Bed

    SciTech Connect

    ETO, J.; LASSETER, R.; SCHENKMAN, B.; STEVENS, J.; KLAPP, D.; VOLKOMMER, H.; LINTON, E.; HURTADO, H.; ROY, J.

    2010-06-08

    The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1 a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2 an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3 a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources.

  7. Fluidized bed heat treating system

    DOEpatents

    Ripley, Edward B; Pfennigwerth, Glenn L

    2014-05-06

    Systems for heat treating materials are presented. The systems typically involve a fluidized bed that contains granulated heat treating material. In some embodiments a fluid, such as an inert gas, is flowed through the granulated heat treating medium, which homogenizes the temperature of the heat treating medium. In some embodiments the fluid may be heated in a heating vessel and flowed into the process chamber where the fluid is then flowed through the granulated heat treating medium. In some embodiments the heat treating material may be liquid or granulated heat treating material and the heat treating material may be circulated through a heating vessel into a process chamber where the heat treating material contacts the material to be heat treated. Microwave energy may be used to provide the source of heat for heat treating systems.

  8. Advanced expander test bed program

    NASA Technical Reports Server (NTRS)

    Riccardi, D. P.; Mitchell, J. C.

    1993-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust. Contract work began 27 Apr. 1990. During 1992, a major milestone was achieved with the review of the final design of the oxidizer turbopump in Sep. 1992.

  9. Building Controls Virtual Test Bed

    SciTech Connect

    Wetter, Michael; Haves, Philip; Coffey, Brian

    2008-04-01

    The Building Controls Virtual Test Bed (BCVTB) is a modular software environment that is based on the Ptolemy II software environment. The BCVTB can be used for design and analysis of heterogenous systems, such as building energy and controls systems. Our additions to Ptolemy II allow users to Couple to Ptolemy II simulation software such as EnergyPlus, MATLAB/Simulink or Dymola for data exchange during run-time. Future versions of the BCVTS will also contain an interface to BACnet which is a communication protocol for building Control systems, and interfaces to digital/analog converters that allow communication with controls hardware. Through Ptolemy II, the BCVTB provides a graphical model building environment, synchronizes the exchanged data and visualizes the system evolution during run- time.

  10. Metabolic Resistance in Bed Bugs

    PubMed Central

    Mamidala, Praveen; Jones, Susan C.; Mittapalli, Omprakash

    2011-01-01

    Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc.) through gene mutations and increased metabolism. Bed bugs (Cimex lectularius) are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases) towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance) with more emphasis on metabolic resistance. PMID:26467498

  11. Pulsed atmospheric fluidized bed combustion

    SciTech Connect

    Not Available

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  12. Predation on barnacles of intertidal and subtidal mussel beds in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Buschbaum, Christian

    2002-04-01

    Balanids are the numerically dominant epibionts on mussel beds in the Wadden Sea. Near the island of Sylt (German Bight, North Sea), Semibalanus balanoides dominated intertidally and Balanus crenatus subtidally. Field experiments were conducted to test the effects of predation on the density of barnacle recruits. Subtidally, predator exclusion resulted in significantly increased abundances of B. crenatus, while predator exclusion had no significant effects on the density of S. balanoides intertidally. It is suggested that recruitment of B. crenatus to subtidal mussel beds is strongly affected by adult shore crabs ( Carcinus maenas) and juvenile starfish ( Asterias rubens), whereas recruits of S. balanoides in the intertidal zone are mainly influenced by grazing and bulldozing of the very abundant periwinkle Littorina littorea, which is rare subtidally. Thus, not only do the barnacle species differ between intertidal and subtidal mussel beds, but the biotic control factors do so as well.

  13. Measurement of the bed material of gravel-bed rivers

    USGS Publications Warehouse

    Milhous, R.T.; ,

    2002-01-01

    The measurement of the physical properties of a gravel-bed river is important in the calculation of sediment transport and physical habitat values for aquatic animals. These properties are not always easy to measure. One recent report on flushing of fines from the Klamath River did not contain information on one location because the grain size distribution of the armour could not be measured on a dry river bar. The grain size distribution could have been measured using a barrel sampler and converting the measurements to the same as would have been measured if a dry bar existed at the site. In another recent paper the porosity was calculated from an average value relation from the literature. The results of that paper may be sensitive to the actual value of porosity. Using the bulk density sampling technique based on a water displacement process presented in this paper the porosity could have been calculated from the measured bulk density. The principle topics of this paper are the measurement of the size distribution of the armour, and measurement of the porosity of the substrate. The 'standard' method of sampling of the armour is to do a Wolman-type count of the armour on a dry section of the river bed. When a dry bar does not exist the armour in an area of the wet streambed is to sample and the measurements transformed analytically to the same type of results that would have been obtained from the standard Wolman procedure. A comparison of the results for the San Miguel River in Colorado shows significant differences in the median size of the armour. The method use to determine the porosity is not 'high-tech' and there is a need improve knowledge of the porosity because of the importance of porosity in the aquatic ecosystem. The technique is to measure the in-situ volume of a substrate sample by measuring the volume of a frame over the substrate and then repeated the volume measurement after the sample is obtained from within the frame. The difference in the

  14. Erosion of sand from a gravel bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cleaning of fine sediment out of gravel stream beds has become an important method to restore impacted stream habitats. Introducing the increased flows needed to entrain fine sediments without eroding the coarser fractions of the bed and potentially destroying its usefulness as a habitat requires c...

  15. Particle Pressures in Fluidized Beds. Final report

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.

  16. Particle pressures in fluidized beds. Final report

    SciTech Connect

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

  17. Print a Bed Bug Card - (Single Cards)

    EPA Pesticide Factsheets

    Two sets of business-card-sized lists of tips for recognizing bed bugs and the signs of an infestation, including a photo of bed bugs to assist identification. One card is for general use around home or office, the other for travelers.

  18. Bed Bugs: Clinical Relevance and Control Options

    PubMed Central

    Dwyer, Dominic E.; Peñas, Pablo F.; Russell, Richard C.

    2012-01-01

    Summary: Since the late 1990s, bed bugs of the species Cimex lectularius and Cimex hemipterus have undergone a worldwide resurgence. These bed bugs are blood-sucking insects that readily bite humans. Cutaneous reactions may occur and can start out as small macular lesions that can develop into distinctive wheals of around 5 cm in diameter, which are accompanied by intense itching. Occasionally, bullous eruptions may result. If bed bugs are numerous, the patient can present with widespread urticaria or eythematous rashes. Often, bites occur in lines along the limbs. Over 40 pathogens have been detected in bed bugs, but there is no definitive evidence that they transmit any disease-causing organisms to humans. Anemia may result when bed bugs are numerous, and their allergens can trigger asthmatic reactions. The misuse of chemicals and other technologies for controlling bed bugs has the potential to have a deleterious impact on human health, while the insect itself can be the cause of significant psychological trauma. The control of bed bugs is challenging and should encompass a multidisciplinary approach utilizing nonchemical means of control and the judicious use of insecticides. For accommodation providers, risk management procedures should be implemented to reduce the potential of bed bug infestations. PMID:22232375

  19. International Standardization of Bed Rest Standard Measures

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita L.

    2010-01-01

    This slide presentation gives an overview of the standardization of bed rest measures. The International Countermeasures Working Group attempted to define and agree internationally on standard measurements for spaceflight based bed rest studies. The group identified the experts amongst several stakeholder agencys. It included information on exercise, muscle, neurological, psychological, bone and cardiovascular measures.

  20. Prevalence, Knowledge, and Concern About Bed Bugs.

    PubMed

    Kaylor, Mary Beth; Wenning, Paul; Eddy, Christopher

    2015-01-01

    Recent research suggests that the resurgence of bed bugs in the U.S. has occurred at an alarming rate. Assumptions have been made that socioeconomic status is not associated with the prevalence of bed bug infestations. Little information is available at the local level, however, about the prevalence of bed bugs in private homes. The authors' pilot study aimed to identify prevalence, knowledge, and concern about bed bugs in one higher income village in Ohio utilizing survey methodology. Responses from 96 individuals who completed the Prevalence, Knowledge, and Concern About Bed Bugs survey were utilized for analysis. The majority of the sample respondents were white and 95% reported that they owned their residence. Only 6% knew someone with bed bugs. Additionally, 52% reported they were somewhat concerned about bed bugs. About 46% reported that they had changed their behavior. For a higher income area, the prevalence was dissimilar to the rate reported in the general public (about 20%). This suggests that bed bugs may be an environmental issue effecting low-income populations disproportionately. Further research is needed in areas of differing socioeconomic levels.

  1. Bed bugs: clinical relevance and control options.

    PubMed

    Doggett, Stephen L; Dwyer, Dominic E; Peñas, Pablo F; Russell, Richard C

    2012-01-01

    Since the late 1990s, bed bugs of the species Cimex lectularius and Cimex hemipterus have undergone a worldwide resurgence. These bed bugs are blood-sucking insects that readily bite humans. Cutaneous reactions may occur and can start out as small macular lesions that can develop into distinctive wheals of around 5 cm in diameter, which are accompanied by intense itching. Occasionally, bullous eruptions may result. If bed bugs are numerous, the patient can present with widespread urticaria or eythematous rashes. Often, bites occur in lines along the limbs. Over 40 pathogens have been detected in bed bugs, but there is no definitive evidence that they transmit any disease-causing organisms to humans. Anemia may result when bed bugs are numerous, and their allergens can trigger asthmatic reactions. The misuse of chemicals and other technologies for controlling bed bugs has the potential to have a deleterious impact on human health, while the insect itself can be the cause of significant psychological trauma. The control of bed bugs is challenging and should encompass a multidisciplinary approach utilizing nonchemical means of control and the judicious use of insecticides. For accommodation providers, risk management procedures should be implemented to reduce the potential of bed bug infestations.

  2. Modeling of fluidized bed silicon deposition process

    NASA Technical Reports Server (NTRS)

    Kim, K.; Hsu, G.; Lutwack, R.; PRATURI A. K.

    1977-01-01

    The model is intended for use as a means of improving fluidized bed reactor design and for the formulation of the research program in support of the contracts of Silicon Material Task for the development of the fluidized bed silicon deposition process. A computer program derived from the simple modeling is also described. Results of some sample calculations using the computer program are shown.

  3. Fluidized-bed copper oxide process

    SciTech Connect

    Shah, P.P.; Takahashi, G.S.; Leshock, D.G.

    1991-10-14

    The fluidized-bed copper oxide process was developed to simultaneously remove sulfur dioxide and nitrogen oxide contaminants from the flue gas of coal-fired utility boilers. This dry and regenerable process uses a copper oxide sorbent in a fluidized-bed reactor. Contaminants are removed without generating waste material. (VC)

  4. Palynology of late Middle Pennsylvanian coal beds in the Appalachian Basin

    USGS Publications Warehouse

    Eble, C.F.

    2002-01-01

    Fossil spores and pollen have long been recognized as valuable tools for identifying and correlating coal beds. This paper describes the palynology of late Middle Pennsylvanian coal beds in the Appalachian Basin with emphasis on forms that assist both intra- and interbasinal coal bed correlation. Stratigraphically important palynomorphs that originate in late Middle Pennsylvanian strata include Torispora securis, Murospora kosankei, Triquitrites minutus, Cadiospora magna, Mooreisporites inusitatus, and Schopfites dimorphus. Taxa that terminate in the late Middle Pennsylvanian include Radiizonates difformis, Densosporites annulatus, Dictyotriletes bireticulatus, Vestispora magna, and Savitrisporites nux. Species of Lycospora, Cirratriradites, Vestispora, and Thymospora, as well as Granasporites medius, Triquitrites sculptilis, and T. securis and their respective ranges slightly higher, in earliest Late Pennsylvanian age strata. Late Middle Pennsylvanian and earliest Late Pennsylvanian strata in the Appalachian Basin correlate with the Radiizonates difformis (RD), Mooreisporites inusitatus (MI), Schopfites colchesterensis-S. dimorphus (CP), and Lycospora granulata-Granasporites medius (GM) spore assemblage zones of the Eastern Interior, or Illinois Basin. In the Western Interior Basin, these strata correlate with the middle-upper portion of the Torispora securis-Laevigatosporites globosus (SG) and lower half of the Thymospora pseudothiessenii-Schopfites dimorphus (PD) assemblage zones. In western Europe, late Middle Pennsylvanian and earliest Late Pennsylvanian strata correlate with the middle-upper portion of the Torispora securis-T. laevigata (SL) and the middle part of the Thymospora obscura-T. thiessenii (OT) spore assemblage zones. Allegheny Formation coal beds also correlate with the Torispora securis (X) and Thymospora obscura (XI) spore assemblages, which were developed for coal beds in Great Britain. ?? 2002 Elsevier Science B.V. All rights reserved.

  5. Development and Testing of a Moving Granular Bed Filter at the Taiwan Industrial Technology Research Institute

    SciTech Connect

    Peng, C.Y.; Hsiau, S-S.; Lee, H-T.; Smid, J.; Wu, T-C.

    2002-09-18

    The main purpose of developing high temperature gas cleaning technologies are to clean the gas under high temperature in order to be cost effective and to improve energy efficiency. Moving granular bed filters are technically and economically applicable for high temperature cleaning system because of low cost, possible to keep operation at a constant pressure drop, simple structure, easy in operation and maintenance, no high risk internals, and more tolerant to process thermal flow. Energy and Resource Laboratories, Taiwan Industrial Technology Research Institute (ERL/ITRI) has been developing a moving granular bed filter (MGBF) for BIGCC(Biomass Integrated Gasification Combined Cycle) high temperature gas cleanup. The filter granules move downwards directed by louver-like guide plates and the hot gases penetrate the MGBF horizontally. Filtration mechanisms include collection of the dust cake over the bed media surface and deep bed filtration. Stagnant zones of filter granules combining with the dusts always exist along the louver walls. Such stagnant zones often corrode the louver-like guide plates, increase the system pressure drop and decrease the total reaction efficiency that may endanger MGBF operation. Series louver and inert structure research that modify the granular flow pattern have been designed to eliminate the formation of these stagnant zones. By connecting to an auxiliary dust/bed media separation system, MGBF can be operated continuously at a stable pressure drop with a stable high efficiency. There are several MGBF R&D activities in progress: (1) a 3-dimensional cold flow system for testing the MGBF filtration efficiency; (2) a high temperature gas cleanup experimental system that has been designed and installed; (3) a 2-dimensional flow pattern experimental system for approving design concepts.

  6. Peering inside the granular bed: illuminating feedbacks between bed-load transport and bed-structure evolution

    NASA Astrophysics Data System (ADS)

    Houssais, M.; Jerolmack, D. J.; Martin, R. L.

    2013-12-01

    The threshold of motion is perhaps the most important quantity to determine for understanding rates of bed load transport, however it is a moving target. Decades of research show that it changes in space and in time within a river, and is highly variable among different systems; however, these differences are not mechanistically understood. Recent researchers have proposed that the critical Shields stress is strongly dependent on the local configuration of the sediment bed [Frey and Church, 2011]. Critical Shields stress has been observed to change following sediment-transporting flood events in natural rivers [e.g., Turowski et al., 2011], while small-scale laboratory experiments have produced declining bed load transport rates associated with slow bed compaction [Charru et al., 2004]. However, no direct measurements have been made of the evolving bed structure under bed load transport, so the connection between granular controls and the threshold of motion remains uncertain. A perspective we adopt is that granular effects determine the critical Shields stress, while the fluid supplies a distribution of driving stresses. In order to isolate the granular effect, we undertake laminar bed load transport experiments using plastic beads sheared by a viscous oil in a small, annular flume. The fluid and beads are refractive index matched, and the fluid impregnated with a fluorescing powder. When illuminated with a planar laser sheet, we are able to image slices of the granular bed while also tracking the overlying sediment transport. We present the first results showing how bed load transport influences granular packing, and how changes in packing influence the threshold of motion to feed back on bed load transport rates. This effect may account for much of the variability observed in the threshold of motion in natural streams, and by extension offers a plausible explanation for hysteresis in bed load transport rates observed during floods. Charru, F., H. Mouilleron, and

  7. Does bedding affect the airway and allergy?

    PubMed

    Siebers, R W; Crane, J

    2011-04-01

    Various cross-sectional and longitudinal studies have suggested that synthetic bedding is associated with asthma, allergic rhinitis and eczema while feather bedding seems to be protective. Synthetic bedding items have higher house dust mite allergen levels than feather bedding items. This is possibly the mechanism involved although fungal and bacterial proinflammatory compounds and volatile organic compounds may play a role. In this review we present and discuss the epidemiological evidence and suggest possible mechanisms. Primary intervention studies are required to show whether feather bedding is protective for the development of childhood asthma and allergic diseases while secondary intervention studies are required to potentially reduce symptoms and medication use in subjects with established disease.

  8. Bed bugs: they are back! The role of the school nurse in bed bug management.

    PubMed

    Sciscione, Patricia

    2012-09-01

    Recently there has been a resurgence of bed bugs in all facets of our society. Bed bugs have even been found in schools, causing unnecessary exclusion of students and unfounded hysteria. School nurses are again called upon to be front-line sources of information to quell the hysteria and confusion related to this unsavory condition. By arming themselves with the best evidence regarding proper identification of bed bugs and their bites and information about integrated prevention measures to control transmission of infestations, school nurses can contribute to the control and management of bed bugs and aid in the overall battle against this "new and improved" invasion of the bed bugs.

  9. Air-based coal gasification in a two-chamber gas reactor with circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Dubinin, A. M.; Tuponogov, V. G.; Kagramanov, Y. A.

    2017-01-01

    During the bed gasification of solid fuels, the process temperature in the reaction zone is not high enough for reaching the maximum rate of the chemical efficiency factor of the gasification process. In order to increase the chemical efficiency factor, it is necessary to supply extra heat to the reaction zone to increase the reaction temperature. In this article, coal gasification in a chamber with forced fluidized bed is considered and it is proposed to supply extra heat with a circulating flow of an inert particulate heat transfer agent. Circulating inert particulate material is successively heated by coal combustion in a cone chamber with bubbling fluidized bed and in a combustion chamber with a spherical nozzle that inhibits the forced fluidized bed. After that, the heat transfer agent heated to 930-950°C enters first in a gasification chamber with bubbling bed and then in a chamber with forced fluidized bed, where it transfers the physical heat to the air fuel mixture. The experiments conducted with crushed Borodinsky coal and inert particulate heat transfer agent (electrocorundum) showed the temperature rise in a gasification chamber with from 760 to 870°C and the increase in the combustible component (CO) concentration in the gasification products by 5.5%. Based on the kinetic equations of the fuel combustion reactions and the CO2 reduction to CO and on the thermal balance equations of combustion and gasification chambers, the simulation model for the gas composition and the temperature rate calculated by the height of reaction chambers was developed. The experimental temperature rates and product gas compositions are in good agreement with the simulation results based on the proposed kinetic gasification model.

  10. Chemical, physical, and environmental properties of pelleted newspaper compared to wheat straw and wood shavings as bedding for horses.

    PubMed

    Ward, P L; Wohlt, J E; Katz, S E

    2001-06-01

    Two experiments were conducted comparing pelleted recycled newspaper (PN) to wheat straw (S) and kiln-dried pine wood shavings (WS) as an animal bedding material. Adult horses housed 20 to 21 h/d in boxstalls served as the animal model for comparisons. In Exp. 1 eight boxstalls, each housing one horse, were each bedded with two types of PN (0.32 and 0.64 x 2.54 cm), S, and WS over four 5-d periods (replicated 4 x 4 Latin square). Initial amounts of bedding materials surpassed most commercial conditions, but stalls were cleaned daily of feces only and additional clean bedding was added as needed to maintain animal cleanliness, thus challenging the bedding properties of each material. In Exp. 2 nine boxstalls were bedded with PN (0.32 x 2.54 cm), S, and WS over three 14-d periods (three 3 x 3 Latin squares) during summer and autumn. Feces and wet spots were removed daily and clean bedding was added to reestablish working volume and simulate commercial conditions. In Exp. 1 and 2 daily additions of clean bedding varied (P < 0.05) with material (S > WS > PN). The higher water-holding capacity of PN and WS contributed to fewer bedding replacements. Usage of each material was greater (P < 0.05) during the autumn; PN had the greatest increase. Type of material and season also influenced bedding environment. Bedding pH increased (P < 0.05) with use and was highest in PN and lowest in S. Higher concentrations of breathable NH3 N were present in stalls bedded with PN and during autumn. Higher pH of used PN and decreased ventilation due to closed doors and windows during autumn were contributing factors. Season, type of bedding, and duration of its use affected (P < 0.05) numbers as well as species of microorganisms present in the breathing zone, nasal cavity, and on the leg of the horse. Clean and used WS contained greater (P < 0.05) quantities of particle fines, but with 5 d of use, particle fines in PN also increased. Quantities of breathable dust during cleaning of stalls

  11. New Madrid Seismic Zone

    DTIC Science & Technology

    2007-11-02

    NEW MADRID SEISMIC ZONE BY COLONEL J.DAVID NORWOOD United States Army DISTRIBUTION STATEMENT A...mCTBB l USAWC STRATEGY RESEARCH PROJECT New Madrid Seismic Zone by J. David Norwood, COL, USA Michael A. Pearson, COL, USA Project Advisor The...ABSTRACT AUTHOR: J. David Norwood, Colonel, U.S. Army TITLE: New Madrid Seismic Zone FORMAT: Strategy Research Project DATE: 22 April 1998 . PAGES:

  12. Cross-bedding related anisotropy and its interplay with various boundary conditions in the formation and orientation of joints in an aeolian sandstone

    NASA Astrophysics Data System (ADS)

    Deng, Shang; Cilona, Antonino; Morrow, Carolyn; Mapeli, Cesar; Liu, Chun; Lockner, David; Prasad, Manika; Aydin, Atilla

    2015-08-01

    Previous research revealed that the cross-bedding related anisotropy in Jurassic aeolian Aztec Sandstone cropping out in the Valley of Fire State Park, Nevada, affects the orientation of compaction bands, also known as anti-cracks or closing mode structures. We hypothesize that cross-bedding should have a similar influence on the orientation of the opening mode joints within the same rock at the same location. To test this hypothesis, we investigated the relationship between the orientation of cross-beds and the orientation of different categories of joint sets including cross-bed package confined joints and joint zones in the Aztec Sandstone. The field data show that the cross-bed package confined joints occur at high-angle to bedding and trend roughly parallel to the dip direction of the cross-beds. In comparison, the roughly N-S trending joint zones appear not to be influenced by the cross-beds in any significant way but frequently truncate against the dune boundaries. To characterize the anisotropy due to cross-bedding in the Aztec Sandstone, we measured the P-wave velocities parallel and perpendicular to bedding from 11 samples and determined an average P-wave anisotropy to be slightly larger than 13%. From these results, a model based on the generalized Hooke's law for anisotropic materials is used to analyze deformation of cross-bedded sandstone as a transversely isotropic material. In the analysis, the dip angle of cross-beds is assumed to be constant and the strike orientation varying from 0° to 359° in the east (x), north (y), and up (z) coordinate system. We find qualitative agreement between most of the model results and the observed field relations between cross-beds and the corresponding joint sets. The results also suggest that uniaxial extension (εzz > εxx = εyy = 0) and axisymmetric extension (εxx = εyy < εzz and εxx = εyy > εzz) would amplify the influence of cross-bedding associated anisotropy on the joint orientation whereas a

  13. Method for loading resin beds

    DOEpatents

    Notz, Karl J.; Rainey, Robert H.; Greene, Charles W.; Shockley, William E.

    1978-01-01

    An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H.sup.+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145.degree.-200.degree. C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145.degree. C with a second aqueous component to provide a gaseous phase containing HNO.sub.3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate.

  14. Mechanisms of turbulence production and dissipation within an idealised permeable bed revealed using endoscopic PIV

    NASA Astrophysics Data System (ADS)

    Lead, J.; Sambrook Smith, G.; Best, J.; Hardy, R. J.; Blois, G.

    2010-12-01

    Porous media are encountered in a wide variety of geophysical systems such as subsurface reservoirs, non-cohesive sediment beds and forests. As the bed permeability and free flow velocity increase, the pore flow may become turbulent, resulting in the initiation of coherent flow structures within the pore space (non-Darcian flows). This situation is commonly found for cases that can be classified as ‘hybrid porous media’, i.e. those that possess a fluid-saturated porous media bounded by a free-stream flow. Many geophysical environments, such as gravel-bed rivers and vegetation immersed within atmospheric boundary layers, can be classified as such. In these systems, turbulence penetrates from the free-stream domain and may extend to a significant portion of the porous domain. Thus for river beds there will be a transition from a turbulent to a laminar regime (Goharzadeh et al. 2005) with depth within the bed. Pore-space turbulence in such environments is significant as it controls pore-space mixing and governs the kinetics of the bio-chemical processes occurring within the hyporheic zone as well as sediment infiltration. However, the nature of turbulence at the scale of the individual pore space, and the formation of pore-space coherent structures, remains largely unexplored due to the technical challenges of collecting data within a porous media. This paper details the initiation and evolution of coherent vortical structures within the individual pore spaces of a permeable bed submerged by a free stream flow. Laboratory experiments were conducted using an idealised permeable bed constructed by packing uniform size spheres (D = 0.04 m) in a cubic arrangement. The instantaneous structure of flow within the permeable bed was obtained using a novel high-resolution E-PIV (Endoscopic Particle Image Velocimetry) technique that allowed visualisation of coherent vortices in the pore space, as well as investigation of their formative mechanisms and temporal evolution

  15. Geochemistry, petrology, and palynology of the Pond Creek coal bed, northern Pike and southern Martin counties, Kentucky

    USGS Publications Warehouse

    Hower, J.C.; Ruppert, L.F.; Eble, C.F.; Clark, W.L.

    2005-01-01

    The geochemistry, petrology, and palynology of the Duckmantian-age Pond Creek coal bed were investigated in northern Pike and southern Martin counties, eastern Kentucky. The coal bed exhibits significant vertical variation in the investigated geochemical parameters, with many diagenetic overprints of the original geochemistry. Included in the range of geochemical signatures are the presence of elements, particularly TiO2 and Zr, suggesting the detrital influences at the time of deposition of a low-vitrinite durain; a high CaO zone with elevated B/Be, both suggesting marine influence, in a lithotype in the middle of the coal bed; and the postdepositional emplacement of pyrite in the uppermost lithotype. Individual lithotypes, each representing distinct depositional environments, all complicated to some degree by diagentic overprints, comprise the complex history of the coal bed. ?? 2004 Elsevier B.V. All rights reserved.

  16. Surf Zone Currents. Volume I. State of Knowledge.

    DTIC Science & Technology

    1982-09-01

    this way, modern turbulent boun- dary layer theory is incorporated into the bed shear-stress model . Expre - sions for the shear stress at this...factor from a surf zone force balance. The modified model also includes new formulations for lateral turbulent mixing and the *" breaking criteria, y...percent of mean velo- cities, as in normal turbulence (Longuet-Higgins,1972a). 99 p. - *ff f -t. . -. . . . i i I .. - 1 ’ 1 " i " -.. All other models

  17. Dating the Naisiusiu Beds, Olduvai Gorge, by electron spin resonance

    NASA Astrophysics Data System (ADS)

    Skinner, A. R.; Hay, R. L.; Masao, F.; Blackwell, B. A. B.

    2003-05-01

    The lower beds at Olduvai Gorge are well known for containing early hominid fossils and Oldowan stone tools, and their ages have been established by 40Ar/ 39Ar dating and paleomagnetic stratigraphy. Ages are generally less certain for the upper deposits at Olduvai Gorge because of the scarcity of datable tuffs. The youngest archaeologically significant site at Olduvai is microlithic LSA, which lies in the type section of the Naisiusiu Beds. The age for the site is controversial, with 14C dates of 17,000-17,550 (Hay, R.L., 1976 Geology of Olduvai Gorge, University of California Press, Berkeley) and >42,000 BP (Manega, P.C., 1993. Geochronology, geochemistry, and isotopic study of the Plio-Pleistocene Hominid sites and the Ngorongoro Volcanic Highland in Northern Tanzania. Unpublished Ph.D. Thesis, University of Colorado, Boulder, CO). The tuff bed in the zone with artifacts does not contain materials datable by 40Ar/ 39Ar, and some other dating method was needed. In the summer of 2001, five equid teeth were collected from the type Naisiusiu site. Another tooth had previously been collected. ESR ages have been determined for three teeth from the archaeological level and their ages cluster around 62±5 ka, assuming linear uranium uptake. Another tooth from a level without artifacts and believed to be significantly younger dated to 39±5 ka, again assuming LU. These dates are considerably older than previous estimates and suggest that the East African MSA/LSA transition occurred very early.

  18. Test bed ion engine development

    NASA Technical Reports Server (NTRS)

    Aston, G.; Deininger, W. D.

    1984-01-01

    A test bed ion (TBI) engine was developed to serve as a tool in exploring the limits of electrostatic ion thruster performance. A description of three key ion engine components, the decoupled extraction and amplified current (DE-AC) accelerator system, field enhanced refractory metal (FERM) hollow cathode and divergent line cusp (DLC) discharge chamber, whose designs and operating philosophies differ markedly from conventional thruster technology is given. Significant program achievements were: (1) high current density DE-AC accelerator system operation at low electric field stress with indicated feasibility of a 60 mA/sq cm argon ion beam; (2) reliable FERM cathode start up times of 1 to 2 secs. and demonstrated 35 ampere emission levels; (3) DLC discharge chamber plasma potentials negative of anode potential; and (4) identification of an efficient high plasma density engine operating mode. Using the performance projections of this program and reasonable estimates of other parameter values, a 1.0 Newton thrust ion engine is identified as a realizable technology goal. Calculations show that such an engine, comparable in beam area to a J series 30 cm thruster, could, operating on Xe or Hg, have thruster efficiencies as high as 0.76 and 0.78 respectively, with a 100 eV/ion discharge loss.

  19. The Virtual Test Bed Project

    NASA Technical Reports Server (NTRS)

    Rabelo, Luis C.

    2002-01-01

    This is a report of my activities as a NASA Fellow during the summer of 2002 at the NASA Kennedy Space Center (KSC). The core of these activities is the assigned project: the Virtual Test Bed (VTB) from the Spaceport Engineering and Technology Directorate. The VTB Project has its foundations in the NASA Ames Research Center (ARC) Intelligent Launch & Range Operations program. The objective of the VTB project is to develop a new and unique collaborative computing environment where simulation models can be hosted and integrated in a seamless fashion. This collaborative computing environment will be used to build a Virtual Range as well as a Virtual Spaceport. This project will work as a technology pipeline to research, develop, test and validate R&D efforts against real time operations without interfering with the actual operations or consuming the operational personnel s time. This report will also focus on the systems issues required to conceptualize and provide form to a systems architecture capable of handling the different demands.

  20. CERTS Microgrid Laboratory Test Bed

    SciTech Connect

    Lasseter, R. H.; Eto, J. H.; Schenkman, B.; Stevens, J.; Volkmmer, H.; Klapp, D.; Linton, E.; Hurtado, H.; Roy, J.

    2010-06-08

    CERTS Microgrid concept captures the emerging potential of distributed generation using a system approach. CERTS views generation and associated loads as a subsystem or a 'microgrid'. The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system can disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. CERTS Microgrid concepts were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resynchronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults.

  1. Keeping tabs on seagrass beds

    SciTech Connect

    Kuhl, D.E.; Sargent, F.J.; Leary, T.J.

    1997-06-01

    Seagrasses form the foundation of complex, fragile communities that include marine and estuarine animals, especially larval and juvenile fish, providing critical shelter and sustenance. Seagrasses also have a role in providing habitat for waterfowl, marine turtles and manimals. In addition, seagrasses improve water quality by stabilizing mobile sediments and converting some pollutants into plant biomass. The issue of propeller scarring or propeller dredging in seagrass beds has received much attention since 1990. The scarring of seagrass results from personal watercraft. Heightened interest has instigated numerous monitoring and mapping projects on propeller scarring and regrowth characteristics within seagrasses. The study areas selected for this paper are located within Tampa Bay, Florida. Specifically, they are Shell Island and Miquel Bay. Spatial monitoring for the extent of seagrass scarring in the Tampa Bay region was conducted in two ways, a regional (general) approach and a site specific (detailed) approach. Regional monitoring assessed the status of seagrass in Tampa Bay and identified {open_quote}hot spots{close_quote}. After identifying {open_quote}hot spots{close_quote}, boat surveys were used to confirm or deny the initial assessment. This poster involves the design of a propeller scarring monitoring program using several methods: Hi8 video, digital cameras, film cameras, and differential GPS combined with Arcview. A pilot program to evaluate the adequacy of these monitoring devices and the recommendation of specific actions in areas of severe propeller scarring will be presented.

  2. Condensation in Nanoporous Packed Beds.

    PubMed

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

    2016-05-10

    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

  3. Preference for bedding material in Syrian hamsters.

    PubMed

    Lanteigne, M; Reebs, S G

    2006-10-01

    This study aimed to determine whether Syrian (golden) hamsters, Mesocricetus auratus, prefer certain bedding materials and whether bedding material can affect paw condition, body weight gain and wheel-running activity. In a first experiment, 26 male hamsters had access to two connected cages, each cage containing a different bedding material (either pine shavings, aspen shavings, corn cob or wood pellets). In a second experiment, 14 male hamsters had access to four connected cages that contained the different bedding materials and also a piece of paper towel to serve as nest material. In a third experiment, 30 male hamsters were each placed in a single cage, 10 of them with pine shavings, 10 with aspen shavings and 10 with corn cob, and they were monitored for 50 days. Significant preferences in the first experiment were: pine shavings over aspen shavings, corn cob over wood pellets, pine shavings over corn cob and aspen shavings over wood pellets (aspen shavings versus corn cob was not tested). However, there was no significant preference expressed in the second experiment, suggesting that the general preference for shavings in the first experiment was based on bedding material suitability as a nesting material. No significant effect of bedding material on paw condition, body weight gain and wheel-running activity was detected. None of the four bedding materials tested in this study can be judged to be inappropriate in the short term if nesting material is added to the cage and if the litter is changed regularly.

  4. Modeling nitrate removal in a denitrification bed.

    PubMed

    Ghane, Ehsan; Fausey, Norman R; Brown, Larry C

    2015-03-15

    Denitrification beds are promoted to reduce nitrate load in agricultural subsurface drainage water to alleviate the adverse environmental effects associated with nitrate pollution of surface water. In this system, drainage water flows through a trench filled with a carbon media where nitrate is transformed into nitrogen gas under anaerobic conditions. The main objectives of this study were to model a denitrification bed treating drainage water and evaluate its adverse greenhouse gas emissions. Field experiments were conducted at an existing denitrification bed. Evaluations showed very low greenhouse gas emissions (mean N2O emission of 0.12 μg N m(-2) min(-1)) from the denitrification bed surface. Field experiments indicated that nitrate removal rate was described by Michaelis-Menten kinetics with the Michaelis-Menten constant of 7.2 mg N L(-1). We developed a novel denitrification bed model based on the governing equations for water flow and nitrate removal kinetics. The model evaluation statistics showed satisfactory prediction of bed outflow nitrate concentration during subsurface drainage flow. The model can be used to design denitrification beds with efficient nitrate removal which in turn leads to enhanced drainage water quality.

  5. Factors Associated With Infant Bed-Sharing

    PubMed Central

    Heere, Megan; Moughan, Beth; Alfonsi, Joseph; Rodriguez, Jennifer; Aronoff, Stephen

    2017-01-01

    Objective: Bed-sharing is associated with sudden infant death syndrome and accidental suffocation and strangulation in bed. The purpose of this study was to identify risk factors for newborn bed-sharing. Methods: Postpartum mothers from a university maternity service were contacted by phone to complete a survey. Demographic and environmental data were collected; newborn bed-sharing and sleep environment were self-reported. Results: A total of 1261 mothers completed surveys; bed-sharing was reported by 79 mothers (6.3%). Multivariate logistic regression identified referral to a nurse (odds ratio [OR] = 10; 95% confidence interval [CI] = 4.5-30) and sleep location “other” than a crib, bassinet, or Pack and Play (OR = 7.1; 95% CI = 1.9-25.9) as factors associated with an increased risk of bed-sharing; formula feeding (OR = 0.4; 95% CI = 0.20-0.77) and crib sleeping (OR = 0.49; 95% CI = 0.26-0.86) reduced this risk. Conclusion: Infants with no identifiable places to sleep, significant health issues, and who are breastfed are more likely to bed-share. Interventional studies should be directed at these factors. PMID:28229101

  6. Fluidized bed combustor and tube construction therefor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1981-01-01

    A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

  7. Tube construction for fluidized bed combustor

    DOEpatents

    De Feo, Angelo; Hosek, William

    1984-01-01

    A fluidized bed combustor comprises a reactor or a housing which has a windbox distributor plate adjacent the lower end thereof which contains a multiplicity of hole and air discharge nozzles for discharging air and coal into a fluidized bed which is maintained above the distributor plate and below a take-off connection or flue to a cyclone separator in which some of the products of combustion are treated to remove the dust which is returned into the fluidized bed. A windbox is spaced below the fluidized bed and it has a plurality of tubes passing therethrough with the passage of combustion air and fluidizing air which passes through an air space so that fluidizing air is discharged into the reaction chamber fluidized bed at the bottom thereof to maintain the bed in a fluidized condition. A fluid, such as air, is passed through the tubes which extend through the windbox and provide a preheating of the combustion air and into an annular space between telescoped inner and outer tubes which comprise heat exchanger tubes or cooling tubes which extend upwardly through the distributor plate into the fluidized bed. The heat exchanger tubes are advantageously arranged so that they may be exposed in groups within the reactor in a cluster which is arranged within holding rings.

  8. Carbon Sequestration in Olivine and Basalt Powder Packed Beds.

    PubMed

    Xiong, Wei; Wells, Rachel K; Giammar, Daniel E

    2017-02-21

    Fractures and pores in basalt could provide substantial pore volume and surface area of reactive minerals for carbonate mineral formation in geologic carbon sequestration. In many fractures solute transport will be limited to diffusion, and opposing chemical gradients that form as a result of concentration differences can lead to spatial distribution of silicate mineral dissolution and carbonate mineral precipitation. Glass tubes packed with grains of olivine or basalt with different grain sizes and compositions were used to explore the identity and spatial distribution of carbonate minerals that form in dead-end one-dimensional diffusion-limited zones that are connected to a larger reservoir of water in equilibrium with 100 bar CO2 at 100 °C. Magnesite formed in experiments with olivine, and Mg- and Ca-bearing siderite formed in experiments with flood basalt. The spatial distribution of carbonates varied between powder packed beds with different powder sizes. Packed beds of basalt powder with large specific surface areas sequestered more carbon per unit basalt mass than powder with low surface area. The spatial location and extent of carbonate mineral formation can influence the overall ability of fractured basalt to sequester carbon.

  9. Effects of Fucus vesiculosus covering intertidal mussel beds in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Albrecht, A.; Reise, K.

    1994-06-01

    The brown alga Fucus vesiculosus forma mytili (Nienburg) Nienhuis covered about 70% of mussel bed ( Mytilus edulis) surface area in the lower intertidal zone of Königshafen, a sheltered sandy bay near the island of Sylt in the North Sea. Mean biomass in dense patches was 584 g ash-free dry weight m-2 in summer. On experimental mussel beds, fucoid cover enhanced mud accumulation and decreased mussel density. The position of mussels underneath algal canopy was mainly endobenthic (87% of mussels with >1/3 of shell sunk into mud). In the absence of fucoids, mussels generated epibenthic garlands (81% of mussels with <1/3 of shell buried in mud). Mussel density underneath fucoid cover was 40 to 73% of mussel density without algae. On natural beds, barnacles (Balanidae), periwinkles ( Littorina littorea) and crabs (particularly juveniles of Carcinus maenas) were significantly less abundant in the presence of fucoids, presumably because most of the mussels were covered with sediment, whereas in the absence of fucoids, epibenthic mussel clumps provided substratum as well as interstitial hiding places. The endobenthic macrofauna showed little difference between covered and uncovered mussel beds. On the other hand, grazing herbivores — the flat periwinkle Littorina mariae, the isopod Jaera albifrons and the amphipods Gammarus spp. — were more abundant at equivalent sites with fucoid cover. The patchy growth of Fucus vesiculosus on mussel beds in the intertidal Wadden Sea affects mussels and their epibionts negatively, but supports various herbivores and increases overall benthic diversity.

  10. On flow induced kinetic diffusion and rotary kiln bed burden heat transport

    SciTech Connect

    Boateng, A.A.

    1997-07-01

    The cross-section of a partially-filled cylindrical kiln rotating on its horizontal axis and processing granular solids produces a shear zone (active layer) at the free surface which grows with the kiln's rotational rate. The active layer, although relatively thin, compared with the rest of the bed burden, drives all physical/chemical reactions. This is because of the high rate of surface renewal which, in turn, promotes heat exchange between the exposed surface and the higher temperature freeboard gas. Unlike packed beds, particulate diffusion induced by the flow of granules, adds a significant component to the overall heat transfer in the bed. Problem formulation and modeling of heat conduction using flow fields derived from experiments suggest that at slow kiln speeds the diffusion effect may not be recognized due to long term duration of particle contacts and hence packed-bed heat conduction models may provide adequate characterization. However, at moderate and high kiln speeds particle collisions are short-termed and kinetic diffusion contributes to the effective thermal conductivity by as much as tenfold thereby resulting in a well-mixed conditions and a homogeneous bed temperature. Industrial processing ramifications such as kiln speed control and product quality are discussed hereafter.

  11. Marginal Zone Lymphoma

    MedlinePlus

    ... zone lymphomas are a group of indolent (slow-growing) NHL B-cell lymphomas, which account for approximately 12 percent of all B-cell lymphomas. The median age for diagnosis is 65 years old. There are three types of marginal zone lymphoma: ...

  12. Urban Terrain Zone Characteristics

    DTIC Science & Technology

    1987-09-01

    function . An example of the interaction of some of these can result in an exposed surface of decorative brick veneer on a framed stracture . Or, a...Classification System for HOUT Studies . . . . . . . . .- ..- . . . . . . 14 2. Urban Terrain Zones Function /Morphology Relationship...By Function --All Cities Aggregated . . . . . . . . . . . . . . . . . . . 69 6. Building Types: Major Terrain Zones . . . . ...... 103 7. Urban Terrain

  13. Coastal zone management

    NASA Technical Reports Server (NTRS)

    Tilton, E. L., III

    1975-01-01

    A panel of federal and state representatives concerned with coastal zone affairs discussed their problems in this area. In addition, several demonstrations of the application of remote sensing technology to coastal zone management were described. These demonstrations were performed by several agencies in a variety of geographical areas.

  14. Float Zone Workshop

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.

    1980-01-01

    A summary of the Analytical Float Zone Experiment System (AFZES) concept is presented. The types of experiments considered for such a facility are discussed. Reports from various industrial producers and users of float zone material are presented. Special emphasis is placed on state-of-the-art developments in low gravity manufacturing and their applications to space processing.

  15. Subduction of fracture zones

    NASA Astrophysics Data System (ADS)

    Constantin Manea, Vlad; Gerya, Taras; Manea, Marina; Zhu, Guizhi; Leeman, William

    2013-04-01

    Since Wilson proposed in 1965 the existence of a new class of faults on the ocean floor, namely transform faults, the geodynamic effects and importance of fracture zone subduction is still little studied. It is known that oceanic plates are characterized by numerous fracture zones, and some of them have the potential to transport into subduction zones large volumes of water-rich serpentinite, providing a fertile water source for magma generated in subduction-related arc volcanoes. In most previous geodynamic studies, subducting plates are considered to be homogeneous, and there is no clear indication how the subduction of a fracture zone influences the melting pattern in the mantle wedge and the slab-derived fluids distribution in the subarc mantle. Here we show that subduction of serpentinized fracture zones plays a significant role in distribution of melt and fluids in the mantle wedge above the slab. Using high-resolution tree-dimensional coupled petrological-termomechanical simulations of subduction, we show that fluids, including melts and water, vary dramatically in the region where a serpentinized fracture zone enters into subduction. Our models show that substantial hydration and partial melting tend to concentrate where fracture zones are being subducted, creating favorable conditions for partially molten hydrous plumes to develop. These results are consistent with the along-arc variability in magma source compositions and processes in several regions, as the Aleutian Arc, the Cascades, the Southern Mexican Volcanic Arc, and the Andean Southern Volcanic Zone.

  16. Investigating Aquatic Dead Zones

    ERIC Educational Resources Information Center

    Testa, Jeremy; Gurbisz, Cassie; Murray, Laura; Gray, William; Bosch, Jennifer; Burrell, Chris; Kemp, Michael

    2010-01-01

    This article features two engaging high school activities that include current scientific information, data, and authentic case studies. The activities address the physical, biological, and chemical processes that are associated with oxygen-depleted areas, or "dead zones," in aquatic systems. Students can explore these dead zones through both…

  17. Microgravity silicon zoning investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.; Gill, G. L., Jr.

    1983-01-01

    A resistance heated zoner, suitable for early zoning experiments with silicon, was designed and put into operation. The initial power usage and size was designed for an shown to be compatible with payload carriers contemplated for the Shuttle. This equipment will be used in the definition and development of flight experiments and apparatus for float zoning silicon and other materials in microgravity.

  18. Mapping Sargassum beds off, ChonBuri Province, Thailand, using ALOS AVNI2 image

    NASA Astrophysics Data System (ADS)

    Noiraksar, Thidarat; Komatsu, Teruhisa; Sawayama, Shuhei; Phauk, Sophany; Hayashizaki, Ken-ichi

    2012-10-01

    Sargassum species grow on rocks and dead corals and form dense seaweed beds. Sargassum beds play ecological roles such as CO2 uptake and O2 production through photosynthesis, spawning and nursery grounds of fish, feeding ground for sea urchins and abalones, and substrates for attached animals and plants on leaves and holdfasts. However, increasing human impacts and climate change decrease or degrade Sargassum beds in ASEAN countries. It is necessary to grasp present spatial distributions of this habitat. Thailand, especially its coastal zone along the Gulf of Thailand, is facing degradation of Sargassum beds due to increase in industries and population. JAXA launched non-commercial satellite, ALOS, providing multiband images with ultra-high spatial resolution optical sensors (10 m), AVNIR2. Unfortunately, ALOS has terminated its mission in April 2011. However, JAXA has archived ALOS AVNIR2 images over the world. They are still useful for mapping coastal ecosystems. We examined capability of remote sensing with ALOS AVNIR2 to map Sargassum beds in waters off Sattahip protected area as a natural park in Chon Buri Province, Thailand, threatened by degradation of water quality due to above-mentioned impacts. Ground truth data were obtained in February 2012 by using continual pictures taken by manta tow. Supervised classification could detect Sargassum beds off Sattahip at about 70% user accuracy. It is estimated that error is caused by mixel effect of bottom substrates in a pixel with 10 x 10 m. Our results indicate that ALOS AVNIR2 images are useful for mapping Sargassum beds in Southeast Asia.

  19. Integrated Use of Fluidized Bed Technology for Oil Production from Oil Shale

    NASA Astrophysics Data System (ADS)

    Siirde, Andres; Martins, Ants

    The plant unit which consists of a fluidized bed retort and CFB furnace for burning the by-products of retorting (semicoke and semicoke gas) is presented in this paper. The oil shale retort consists of a fast fluidized bed shaft, coarse semicoke bit, semicoke separation chamber and cyclone for the separation of fine semicoke particles. The crashed oil shale and hot ash from the CFB ash separator are fed concurrently into the fast fluidized bed shaft. For fluidizing the mixture of oil shale and hot ash particles, the recycle semicoke gas is used. The pyrolysis of oil shale begins in fluidized bed and is completed in the semicoke separation chamber. The coarse semicoke particles are separated from fluidized bed directly while the medium size particles are separated from the gases in the semicoke separation chamber and the finest semicoke particles in the cyclone. All the fractions of semicoke from the fluidized bed retort and semicoke gas from the oil fractionator are burnt in the CFB furnace. The semicoke ash is separated from flue gases in the CFB ash separator. A part of separated hot ash is fed into the fluidized bed retort as a solid heat carrier material and the rest into the furnace through the ash cooler or separated from the process. The retention of sulphur dioxide formed during the semicoke and semicoke gas combustion, is guaranteed for about 99 % due to the high CaO content in the semicoke ash and convenient temperature (about 850°C) in the CFB furnace. The described plant unit is useful for retorting oil shale and other solid hydrocarbon-containing fuels. The advantages of the present retorting process and system are: improved oil yield, greater throughput, lower retorting time, avoidance of moving parts in the retorting zones, reduced downtime, etc. A new plant unit for oil shale oil production has been elaborated and defended by the Estonian Utility Model EE 200700671 UI.

  20. CCD Multi-Function Processor Test Bed.

    DTIC Science & Technology

    1982-01-01

    AD-A111 335 MITRE CORP BEDFORDMA F/6 9/5 CCD MULTIFUNCTION PROCESSOR TEST BED.(U) JAN 82 M W PACZAN. S M WALOSTEIN F19628-81-C-OO01 UNCLASSIFIED MTR...HAIAf III 4 ESD-TR-81-394 MTR-8417 CCD MULTI-FUNCTION PROCESSOR TEST BED By M. W. Paczan and S. M. Waldstein JANUARY 1982 Prepared for DEPUTY FOR...TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED CCD MULTI-FUNCTION PROCESSOR TEST BED 6. PERFORMING ORG. REPORT NUMBER MTR-8417 7 AUT-OR(s) S

  1. NASA/MSFC nozzle test bed

    NASA Technical Reports Server (NTRS)

    Crose, James G.; Mack, Thomas E.; Marx, Douglas A.; Goldberg, Benjamin; Shrader, John E.

    1989-01-01

    As part of an effort to improve the state-of-the-art in nozzle technology, a solid propulsion test bed facility is being designed and will be located at Marshall Space Flight Center. The test bed will consist of a plasma arc facility and several small scale rocket motor test facilities ranging in size from the ballistic environmental generator motor with a 1/2 in. diameter throat to the MNASA motor with a 9 and 1/2 in. diameter throat capability. The test bed system will be used primarily to study materials behavior from the standpoint of char, erosion, and thermal stress phenomena.

  2. Free running droplets on packed powder beds

    NASA Astrophysics Data System (ADS)

    Whitby, Catherine P.; Bian, Xun; Sedev, Rossen

    2013-06-01

    We observed that water drops placed on horizontal beds of fine molybdenite particles move freely over the bed surface for about 1 second. The drops collect an irregular coating of unevenly distributed particles as they bounce and roll. We manipulated the distance that the drops travel, and hence the area of the droplet surface coated with particles, by varying the water surface tension and the kinetic energy of the initial droplet impact on the bed surface. Our results highlight the role of contact angle hysteresis in particle encapsulation of liquid drops.

  3. Bed bug outbreak in a neonatal unit.

    PubMed

    Bandyopadhyay, T; Kumar, A; Saili, A

    2015-10-01

    There has been a worldwide increase in bed bug infestations over the last 10-15 years. A major stigma is placed upon the institutions found to be infested. We report our experience with an outbreak of the tropical bed bug, Cimex hemipterus, in a neonatal unit. The outbreak not only affected the admitted newborns and mothers by causing a wide variety of rashes and inducing sleeplessness, but also impinged upon the health professionals and their families by producing similar symptomology. It is important for healthcare providers to be aware of, and for each healthcare facility to have, bed bug prevention and control policies.

  4. 75 FR 3859 - Safety Zone; Baltimore Captain of Port Zone

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Baltimore Captain of Port Zone AGENCY... establishing a temporary safety zone in all navigable waters of the Captain of the Port Baltimore zone. The... authorized by the Captain of the Port Baltimore, or his designated representative. This safety zone...

  5. A PROTOTYPE FOUR INCH SHORT HYDRIDE (FISH) BED AS A REPLACEMENT TRITIUM STORAGE BED

    SciTech Connect

    Klein, J.; Estochen, E.; Shanahan, K.; Heung, L.

    2011-02-23

    The Savannah River Site (SRS) tritium facilities have used 1st generation (Gen1) metal hydride storage bed assemblies with process vessels (PVs) fabricated from 3 inch nominal pipe size (NPS) pipe to hold up to 12.6 kg of LaNi{sub 4.25}Al{sub 0.75} metal hydride for tritium gas absorption, storage, and desorption for over 15 years. The 2nd generation (Gen2) of the bed design used the same NPS for the PV, but the added internal components produced a bed nominally 1.2 m long, and presented a significant challenge for heater cartridge replacement in a footprint limited glove-box. A prototype 3rd generation (Gen3) metal hydride storage bed has been designed and fabricated as a replacement candidate for the Gen2 storage bed. The prototype Gen3 bed uses a PV pipe diameter of 4 inch NPS so the bed length can be reduced below 0.7 m to facilitate heater cartridge replacement. For the Gen3 prototype bed, modeling results show increased absorption rates when using hydrides with lower absorption pressures. To improve absorption performance compared to the Gen2 beds, a LaNi{sub 4.15}Al{sub 0.85} material was procured and processed to obtain the desired pressure-composition-temperature (PCT) properties. Other bed design improvements are also presented.

  6. Passive acoustic monitoring of bed load discharge in a large gravel bed river

    NASA Astrophysics Data System (ADS)

    Geay, T.; Belleudy, P.; Gervaise, C.; Habersack, H.; Aigner, J.; Kreisler, A.; Seitz, H.; Laronne, J. B.

    2017-02-01

    Surrogate technologies to monitor bed load discharge have been developed to supplement and ultimately take over traditional direct methods. Our research deals with passive acoustic monitoring of bed load flux using a hydrophone continuously deployed near a river bed. This passive acoustic technology senses any acoustic waves propagated in the river environment and particularly the sound due to interparticle collisions emitted during bed load movement. A data set has been acquired in the large Alpine gravel-bedded Drau River. Analysis of the short-term frequency response of acoustic signals allows us to determine the origin of recorded noises and to consider their frequency variations. Results are compared with ancillary field data of water depth and bed load transport inferred from the signals of a geophone array. Hydrophone and geophone signals are well correlated. Thanks to the large network of deployed geophones, analysis of the spatial resolution of hydrophone measurements shows that the sensor is sensitive to bed load motion not only locally but over distances of 5-10 m (10-20% of river width). Our results are promising in terms of the potential use of hydrophones for monitoring bed load transport in large gravel bed rivers: acoustic signals represent a large river bed area, rather than being local; hydrophones can be installed in large floods; they can be deployed at a low cost and provide continuous monitoring at high temporal resolution.

  7. Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence

    PubMed Central

    Wang, Changlu; Wen, Xiujun

    2011-01-01

    The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We conducted telephone interviews of staff from 77 Health and Epidemic Prevention Stations in six Chinese cities in November 2010. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F.)) are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests) were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts). Although international and domestic travel has increased rapidly in China over the past decade (2000–2010), there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons), hotels, or trains. One city (Shenzhen city near Hong Kong) experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates). There have not been any studies or reports on bed bug insecticide

  8. Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence.

    PubMed

    Wang, Changlu; Wen, Xiujun

    2011-04-11

    The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We conducted telephone interviews of staff from 77 Health and Epidemic Prevention Stations in six Chinese cities in November 2010. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F.)) are known to occur in China. These were common urban pests before the early1980s. Nationwide "Four-Pest Elimination" campaigns (bed bugs being one of the targeted pests) were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts). Although international and domestic travel has increased rapidly in China over the past decade (2000-2010), there have only been sporadic new infestations reported in recent years. During 1999-2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons), hotels, or trains. One city (Shenzhen city near Hong Kong) experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates). There have not been any studies or reports on bed bug insecticide

  9. Do-it-yourself Bed Bug Control

    MedlinePlus

    ... Share Facebook Twitter Google+ Pinterest Contact Us Do-it-yourself Bed Bug Control Información relacionada disponible en ... variation in the length of time needed, but it can be as long as a year). Empty ...

  10. The tendering process for beds and mattresses.

    PubMed

    Ballard, K; Baxter, H

    1998-04-01

    As increasing numbers of expensive, sophisticated bed and mattress systems become available, more trusts are negotiating contracts for supply, maintenance and training. It is important that tissue viability nurses become involved in such decision-making.

  11. Bed Bug Clearinghouse by Type of Resource

    EPA Pesticide Factsheets

    This information is to help states, communities, and consumers prevent and control bed bug infestations. These brochures, fact sheets, manuals, posters, checklists, videos, and more provide guidance such as hotel room inspection and pesticide safety.

  12. Triadic bed-sharing and infant temperature.

    PubMed

    Ball, H L

    2002-09-01

    The effects on infants of sleeping with their parents is currently the subject of much debate. One concern regarding infants who sleep in their parents' bed involves the possibility of overheating. Previous research reported a significantly greater core temperature of 0.1 degrees C among a cohort of bed-sharing infants compared with a matched cohort of infants sleeping alone. This paper presents a preliminary analysis of the overnight rectal temperature of 12 of the 20 infants who were monitored sleeping alone and with their parents on separate nights at the University of Durham Parent-Infant Sleep Lab. No significant differences were found in all night rectal temperature, or temperature from 2 h after sleep onset between bed-sharing and cot sleeping nights. These preliminary analyses suggest a night-time difference in rectal temperature between routine bed-sharers and routine cot sleepers, however, these findings will be further explored in the full analyses for this study.

  13. Monitoring by Control Technique - Electrified Filter Bed

    EPA Pesticide Factsheets

    Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about electrified filter bed control techniques used to reduce pollutant emissions.

  14. Bed Bugs are Public Health Pests

    EPA Pesticide Factsheets

    EPA and the Centers for Disease Control and Prevention (CDC) issued a joint statement on the public health impacts of bed bugs, which are blood-sucking ectoparasites (external parasites). EPA also has a pesticide registration notice on this topic.

  15. Drying of solids in fluidized beds

    SciTech Connect

    Kannan, C.S.; Thomas, P.P.; Varma, Y.B.G.

    1995-09-01

    Fluidized bed drying is advantageously adopted in industrial practice for drying of granular solids such as grains, fertilizers, chemicals, and minerals either for long shelf life or to facilitate further processing or handling. Solids are dried in batch and in continuous fluidized beds corresponding to cross-flow and countercurrent flow of phases covering a wide range in drying conditions. Materials that essentially dry with constant drying rate and then give a falling drying rate approximately linear with respect to solids moisture content (sand) as well as those with an extensive falling rate period with the subsequent falling rate being a curve with respect to the moisture content (mustard, ragi, poppy seeds) are chosen for the study. The performance of the continuous fluidized bed driers is compared with that of batch fluidized bed driers; the performance is predicted using batch kinetics, the residence time distribution of solids, and the contact efficiency between the phases.

  16. Adult Bed-Wetting: A Concern?

    MedlinePlus

    ... D. Bed-wetting that starts in adulthood (secondary enuresis) is uncommon and requires medical evaluation. Causes of ... Erik P. Castle, M.D. References Adult nocturnal enuresis. National Association for Continence. http://www.nafc.org/ ...

  17. Ultra high temperature particle bed reactor design

    NASA Astrophysics Data System (ADS)

    Lazareth, Otto; Ludewig, Hans; Perkins, K.; Powell, J.

    1990-04-01

    A direct nuclear propulsion engine which could be used for a mission to Mars is designed. The main features of this reactor design are high values for I(sub sp) and very efficient cooling. This particle bed reactor consists of 37 cylindrical fuel elements embedded in a cylinder of beryllium which acts as a moderator and reflector. The fuel consists of a packed bed of spherical fissionable fuel particles. Gaseous H2 passes over the fuel bed, removes the heat, and is exhausted out of the rocket. The design was found to be neutronically critical and to have tolerable heating rates. Therefore, this particle bed reactor design is suitable as a propulsion unit for this mission.

  18. Development of fluidized bed cement sintering technology

    SciTech Connect

    Mukai, Katsuji

    1994-12-31

    In the new system presented in this paper, the cement clinker is sintered, not in a rotary kiln, but in two different furnaces: a spouted bed kiln and a fluidized bed kiln. The heat generated in the process of cooling the cement clinker is recovered by a fluidized bed cooler and a packed bed cooler, which are more efficient than the conventional coolers. Compared with the rotary kiln system, the new technology significantly reduces NO{sub x} emissions, appreciably cuts energy consumption, and reduces CO{sub 2} emissions as well. Thus, the new system is an efficient cement sintering system that is friendly to the global environment. In this paper, we describe this new technology as one of the applied technologies at an industrial level that is being developed in the Clean Coal Technology Project, and we present the results from test operations at our pilot plant.

  19. D7 debris-bed experiment. [LMFBR

    SciTech Connect

    Mitchell, G W; Ottinger, C A; Lipinski, R J

    1983-08-01

    The D7 experiment investigated heat removal from a shallow, stratified bed of UO/sub 2/ particulate in sodium. The particle diameters ranged from 0.1 to 1.0 mm, with the largest particles at the bottom. The bed thickness was 74 mm and the average porosity was 41%. The incipient dryout power varied from 0.43 W/g to 0.25 W/g as the sodium subcooling (saturation temperature minus overlying pool temperature) was reduced from 390/sup 0/C to 170/sup 0/C. These powers were only slighlty above the incipient boiling powers. Such low dryout powers are believed due to the interaction of capillary force with bed stratification. With a subccoling of 130/sup 0/C several sudden decreases in the saturation temperature occurred. These are believed due to channel formation, which causes a reduction in the capillary pressure in the bed.

  20. Effects Of Exercise During Bed Rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.; Bernauer, Edmund M.

    1993-01-01

    Pair of reports adds to growing body of knowledge of physical deconditioning caused by prolonged bed rest and effectiveness of various exercise regimens in preserving or restoring fitness. Major objective to determine what regimens to prescribe to astronauts before flight, during prolonged weightlessness, and immediately before returning to Earth. Knowledge also benefits patients confined by illness or injury. First report discusses experiment on effects of two types of periodic, intense, short-duration exercise during bed rest. Experiment also discussed in documents "Effects Of Exercise During Prolonged Bed Rest" (ARC-12190), and "Isotonic And Isokinetic Exercise During Bed Rest" (ARC-12180). Second report reviews knowledge acquired with view toward development of protocols for exercise regimens.

  1. Bed Bug Clearinghouse Publications in Other Languages

    EPA Pesticide Factsheets

    This information is intended to help states, communities, and consumers prevent and control bed bug infestations. These outreach materials are available in Spanish, Chinese, and French; and include action plans based on an IPM approach.

  2. Effect of Bed Characters on the Direct Synthesis of Dimethyldichlorosilane in Fluidized Bed Reactor

    PubMed Central

    Zhang, Pan; Duan, Ji H.; Chen, Guang H.; Wang, Wei W.

    2015-01-01

    This paper presents the numerical investigation of the effects of the general bed characteristics such as superficial gas velocities, bed temperature, bed heights and particle size, on the direct synthesis in a 3D fluidized bed reactor. A 3D model for the gas flow, heat transfer, and mass transfer was coupled to the direct synthesis reaction mechanism verified in the literature. The model was verified by comparing the simulated reaction rate and dimethyldichlorosilane (M2) selectivity with the experimental data in the open literature and real production data. Computed results indicate that superficial gas velocities, bed temperature, bed heights, and particle size have vital effect on the reaction rates and/or M2 selectivity. PMID:25742729

  3. Improved lignin pyrolysis for phenolics production in a bubbling bed reactor--Effect of bed materials.

    PubMed

    Li, Dongbing; Briens, Cedric; Berruti, Franco

    2015-01-01

    Lignin pyrolysis was studied in a bubbling fluidized bed reactor equipped with a fractional condensation train, using nitrogen as the fluidization gas. The effect of different bed materials (silica sand, lignin char, activated lignin char, birch bark char, and foamed glass beads) on bio-oil yield and quality was investigated for a pyrolysis temperature of 550 °C. Results how that a bed of activated lignin char is preferable to the commonly used silica sand: pyrolysis of Kraft lignin with a bed of activated lignin char not only provides a pure char product, but also a higher dry bio-oil yield (with a relative increase of 43%), lower pyrolytic water production, and better bio-oil quality. The bio-oil obtained from Kraft lignin pyrolysis with a bed of activated lignin char has a lower average molecular weight, less tar, more phenolics, and less acidity than when sand is used as bed material.

  4. Fluidized bed injection assembly for coal gasification

    DOEpatents

    Cherish, Peter; Salvador, Louis A.

    1981-01-01

    A coaxial feed system for fluidized bed coal gasification processes including an inner tube for injecting particulate combustibles into a transport gas, an inner annulus about the inner tube for injecting an oxidizing gas, and an outer annulus about the inner annulus for transporting a fluidizing and cooling gas. The combustibles and oxidizing gas are discharged vertically upward directly into the combustion jet, and the fluidizing and cooling gas is discharged in a downward radial direction into the bed below the combustion jet.

  5. Fault zone hydrogeology

    NASA Astrophysics Data System (ADS)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (< 1 km) introduces permeability heterogeneity and anisotropy, which has an important impact on processes such as regional groundwater flow, hydrocarbon migration, and hydrothermal fluid circulation. Fault zones have the capacity to be hydraulic conduits connecting shallow and deep geological environments, but simultaneously the fault cores of many faults often form effective barriers to flow. The direct evaluation of the impact of faults to fluid flow patterns remains a challenge and requires a multidisciplinary research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and

  6. Anomalous zones (domal)

    SciTech Connect

    Kupfer, D.H. )

    1990-09-01

    Each zone contains several anomalous salt properties (anomalous features). Zones cannot be characterized by any single property Zones are highly variable, lenticular, and discontinuous in detail; however, once established, they commonly have a predictable trend. The individual anomalous features can occur alone (locally in pairs) over areas of various sizes and shapes. These alone occurrences are not anomalous zones. Anomalous zones may be of any origin, and origin is not part of the definition. Typical origins include: primary (sedimentary), external sheath zone, separating two spines of salt, or caused by toroidal flow. The major importance of an anomalous zone is that it consists of various anomalous features distributed discontinuously along the zone. Thus, if three or more anomalous properties are observed together, one should look for others. The anomalous zones observed in the Gulf Coast thus far are vertical, linear, and semicontinuous. Most are reasonably straight, but some bend sharply, end abruptly, or coalesce. Textures in salt involve grain size, color (white to dark gray), grain shape, or grain distribution of the salt. Typical anomalous textures are coarse-grain, poikiloblastic, and friability. A change in color is commonplace and seldom anomalous. Structural anomalous features, broadly defined, account for most of the rest of the anomalous features. Not uncommonly they cause mining problems. Among the structural anomalous features: INCLUSIONS: Sediments, hydrocarbons, brine, gases. Common gases are air (as N{sub 2}), CH-compounds, CO{sub 2}, and H{sub 2}S. STRUCTURES: Sheared salt, undue stabbing or jointing, voids (crystal-lined pockets), permeability, increased porosity COMPOSITION: High anhydrite content, visible anhydrite as grains or boudins, very black salt = disseminated impurities such as clay.

  7. Transport of through a Thick Vadose Zone.

    PubMed

    Arnaud, Emmanuelle; Best, Anna; Parker, Beth L; Aravena, Ramon; Dunfield, Kari

    2015-09-01

    Livestock manure applications on fields can be a source of contamination in water resources, including groundwater. Although fecal indicators like have often been detected in tile drainage systems, few studies have monitored groundwater at depth after manure treatments, especially at sites with a deep, heterogeneous vadose zone. Our hypothesis was that microbial transport through a thick vadose zone would be limited or nonexistent due to attenuation processes, subsurface thickness, and heterogeneity. This study tested this hypothesis by monitoring concentrations beneath a 12-m-thick vadose zone of coarse, heterogeneous glacial sediments after surface application of liquid swine manure. was detected on all 23 sample dates over the 5-mo period (4 Apr. 2012-13 Aug. 2012), with particularly elevated concentrations 1 wk after application and lasting for 5 wk. Variable low-level concentrations before and after the elevated period suggest remobilization and delayed transport of microorganisms to the water table without additional loadings within the flow field. These findings suggest preferential flow pathways allowing deep infiltration of manure bacteria as well as a continued source of bacteria, with variable retention and travel times, over several months. Preferential flow pathways at this site include soil macropores, depression focused infiltration, and pathways related to subsurface heterogeneity and/or fracture flow through finer-grained diamict beds. Further research is needed to confirm the relative contribution of sources, constrain travel times, and define specific transport pathways.

  8. Water produced with coal-bed methane

    USGS Publications Warehouse

    ,

    2000-01-01

    Natural gas produced from coal beds (coal-bed methane, CBM) accounts for about 7.5 percent of the total natural gas production in the United States. Along with this gas, water is also brought to the surface. The amount of water produced from most CBM wells is relatively high compared to conventional natural gas wells because coal beds contain many fractures and pores that can contain and transmit large volumes of water. In some areas, coal beds may function as regional or local aquifers and important sources for ground water. The water in coal beds contributes to pressure in the reservoir that keeps methane gas adsorbed to the surface of the coal. This water must be removed by pumping in order to lower the pressure in the reservoir and stimulate desorption of methane from the coal (fi g. 1). Over time, volumes of pumped water typically decrease and the production of gas increases as coal beds near the well bore are dewatered.

  9. The Physiology of Bed Rest. Chapter 39

    NASA Technical Reports Server (NTRS)

    Fortney, Suzanne M.; Schneider, Victor S.; Greenleaf, John E.

    1996-01-01

    Prolonged rest in bed has been utilized by physicians and other health-care workers to immobilize and confine patients for rehabilitation and restoration of health since time immemorial. The sitting or horizontal position is sought by the body to relieve the strain of the upright or vertical postures, for example during syncopal situations, bone fractures, muscle injuries, fatigue, and probably also to reduce energy expenditure. Most health-care personnel are aware that adaptive responses occurring during bed rest proceed concomitantly with the healing process; signs and symptoms associated with the former should be differentiated from those of the latter. Not all illnesses and infirmities benefit from prolonged bed rest. Considerations in prescribing bed rest for patients-including duration, body position, mode and duration of exercise, light-dark cycles, temperature, and humidity-have not been investigated adequately. More recently, adaptive physiological responses have been measured in normal, healthy subjects in the horizontal or slightly head-down postures during prolonged bed rest as analogs for the adaptive responses of astronauts exposed to the microgravity environment of outer and bed-rest research.

  10. CFD-DEM study of effect of bed thickness for bubbling fluidized beds

    SciTech Connect

    Tingwen, Li; Gopalakrishnan, Pradeep; Garg, Rahul; Shahnam, Mehrdad

    2011-10-01

    The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

  11. WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

    SciTech Connect

    Hansen, E. K.

    2015-05-06

    This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

  12. 16. UPPER PASSENGER LOADING ZONE, NOTE LOADING ZONE BELOW WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. UPPER PASSENGER LOADING ZONE, NOTE LOADING ZONE BELOW WITH TURN STILES - Jefferson National Expansion Memorial Arch, Mississippi River between Washington & Poplar Streets, Saint Louis, Independent City, MO

  13. The origin of skarn beds, Ryllshyttan Zn-Pb-Ag + magnetite deposit, Bergslagen, Sweden

    NASA Astrophysics Data System (ADS)

    Jansson, Nils F.; Allen, Rodney L.

    2011-11-01

    component. Subsequently, the calcareous Fe formations were subjected to post-depositional alteration by hydrothermal fluids, locally yielding more manganoan and magnesian assemblages. The Mn-alteration is manifested by lateral gradations from epidote-grandite-clinopyroxene±magnetite rocks into significantly more Mn-rich quartz-spessartine rocks and massive andradite rocks over distances of less than 10 cm within individual skarn beds. Magnesian alteration is manifested by the development of discordant zones of pargasite para-amphibolites and formation of stratiform pargasite rocks texturally similar to the interlaminated grandite-epidote-ferroan diopside rocks. The latter increase in abundance towards the Ryllshyttan deposit and are associated with pre-metamorphic/pre-tectonic K-Mg-Fe±Si alteration (now biotite-phlogopite-garnet-cordierite-pargasite rocks) that is related to base metal mineralization. The zone of Mn- and Mg-altered skarn beds extends beyond the zone of pervasive K-Mg-Fe±Si alteration around Ryllshyttan. This suggests that the skarn bed progenitors, or their sedimentary contacts against rhyolitic ash-siltstones, acted as conduits to outflowing hydrothermal fluids. The chemical and mineralogical imprint, imposed on affected beds by alteration, may serve as indicators of proximity to intense K-Mg-Fe±Si alteration envelopes around other base metal sulphide deposits in Bergslagen. The last recorded event comprised syn-tectonic veining of competent massive andradite skarn beds. The veins contain quartz-albite-epidote-ferroan diopside-actinolite assemblages.

  14. Magnetic fabrics of the Douglas Till of the Superior lobe: exploring bed-deformation kinematics

    NASA Astrophysics Data System (ADS)

    Shumway, Jacqueline R.; Iverson, Neal R.

    2009-01-01

    The Superior lobe of the Laurentide ice sheet, during its last advance into northwestern Wisconsin, may have moved and transported sediment primarily through deep, widespread shear of its bed to high strains (>100). To study the kinematics of this deformation, we measured the anisotropy of magnetic susceptibility of 3750 intact samples of its basal till—the Douglas member of the Miller Creek formation—collected from eight profiles at 0.2 m depth increments. A benchmark for interpretations was provided by results of ring-shear experiments conducted on the Douglas Till, which provided fabric characteristics for the case of horizontal simple shear. Orientations of maximum susceptibility ( k1) were controlled by preferred orientations of silt-sized magnetite grains and were similar to sand-grain orientations measured in thin sections. Strengths of fabrics formed by orientations of k1 indicate that most of the till sampled was deformed but to variable strains. Deformation averaged over the 20 km spanned by the study approximated horizontal simple shear. However, large differences in k1 fabric azimuths (>45°) over lateral distances of meters to tens of meters indicate highly heterogeneous bed deformation, perhaps focused in anastomosing zones with associated divergent and convergent till shear. This interpretation is supported by orientations of principal susceptibilities that imply, in many cases, either that shear planes were steeply dipping, particularly transverse to the shearing direction, or that there were major components of pure shear. Variations in k1 fabric azimuth with depth indicate that most of the till thickness did not shear simultaneously; rather, till accumulated at the bed as shear direction changed in response to temporally shifting zones of shallow deformation (<1 m). This heterogeneous, temporally variable deformation of the bed differs from many applications of the bed-deformation model but is consistent with subglacial measurements at modern

  15. Sealing considerations for repository shafts in bedded and dome salt

    NASA Astrophysics Data System (ADS)

    1981-12-01

    The geologic and hydrologic data base is reviewed for penetration seal designs referenced to the Los Medanos bedded salt site in New Mexico and to four candidate salt domes in the Gulf Interior. Experience with existing shafts highlights the importance, for shaft decommissioning as well as operation, of achieving an adequate seal at and immediately below the top of salt. Possible constuction procedures for repository shafts are reviewed, noting advantages and disadvantages with respect to repository sealing. At this stage, there does not appear to be a clear preference for excavation by drill and blast or by drilling. If conventional drill and blast methods are used, it may be necessary to grout in permeable zones above the salt. An important consideration with respect to sealing is that grouting operations (or freezing should it be used) should not establish connections between the top of salt and waterbearing zones higher in the stratigraphic section. Generally, it is concluded that Los Medanos and the dome salt sites are favorable candidate repository sites from the point of view of sealing.

  16. Buffer Zone Fact Sheets

    EPA Pesticide Factsheets

    New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

  17. Microgravity silicon zoning investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.; Gill, G. L., Jr.

    1985-01-01

    The flow instabilities in floating zones of silicon were investigated and methods for investigation of these instabilities in microgravity were defined. Three principal tasks were involved: (1) characterization of the float zone in small diameter rods; (2) investigation of melt flow instabilities in circular melts in silicon disks; and (3) the development of a prototype of an apparatus that could be used in near term space experiments to investigate flow instabilities in a molten zone. It is shown that in a resistance heated zoner with 4 to 7 mm diameter silicon rods that the critical Marangoni number is about 1480 compared to a predicted value of 14 indicative that viable space experiments might be performed. The prototype float zone apparatus is built and specifications are prepared for a flight zoner should a decision be reached to proceed with a space flight experimental investigation.

  18. Carbon dioxide fumigation for controlling bed bugs.

    PubMed

    Wang, Changlu; Lü, Lihua; Xu, Ming

    2012-09-01

    We investigated the potential of carbon dioxide (CO2) fumigation as a method for controlling bed bugs, Cimex lectularius L. The effect of bed bug developmental stage, temperature, and CO2 concentration on the minimum time to kill 100% of bed bugs was determined. The minimum CO2 concentration lethal to all bed bug stages was approximately 30% with 24 h exposure time at 25 degrees C. The minimum fumigation time required to kill 100% of eggs using 100% CO2 at 20, 25, and 30 degrees C were 3, 7, and 8 h, respectively; the minimum fumigation time to kill 100% of adult males/nymphs were 8, 13, and 14 h, respectively. The minimum time to kill 100% of adult males/nymphs using 50 and 70% CO2 at 25 degrees C were 18 and 16 h, respectively. We found that eggs were not completely killed after 24 h fumigation when the CO2 concentration was lower than 80%. Thus, bed bug eggs were more susceptible to 100% CO2 fumigation than nymphs and adult males but more tolerant than nymphs and adult males with lower CO2 concentration (50-80%). There were no significant differences among nymphs, adult males, and adult females in their susceptibility to 100% CO2 fumigation. A 24 h fumigation in sealed 158 liter (42 gallon) heavy duty garbage bags filled 90% full with fabric materials and/or boxes and 1,350 g dry ice per bag was sufficient to kill all stages of bed bugs hidden in the materials at room temperature (23-24 degrees C). Sealed heavy duty garbage bags maintained > or = 94% CO2 for at least 24 h. Custom-made double zipper plastic bags (122 x 183 cm) were also used to evaluate the effectiveness of CO2 fumigation for controlling bed bugs. Each bag was filled with fabric and boxes to 50-90% full. Bed bugs were hidden in various locations of each bag. CO2 was introduced into the bags through a CO2 cylinder. CO2 fumigation lasting 24-48 h was sufficient to kill all stages of bed bugs at room temperature, depending on the quantity of materials placed in each bag and whether CO2 was

  19. Cascadia Subduction Zone

    USGS Publications Warehouse

    Frankel, Arthur D.; Petersen, Mark D.

    2008-01-01

    The geometry and recurrence times of large earthquakes associated with the Cascadia Subduction Zone (CSZ) were discussed and debated at a March 28-29, 2006 Pacific Northwest workshop for the USGS National Seismic Hazard Maps. The CSZ is modeled from Cape Mendocino in California to Vancouver Island in British Columbia. We include the same geometry and weighting scheme as was used in the 2002 model (Frankel and others, 2002) based on thermal constraints (Fig. 1; Fluck and others, 1997 and a reexamination by Wang et al., 2003, Fig. 11, eastern edge of intermediate shading). This scheme includes four possibilities for the lower (eastern) limit of seismic rupture: the base of elastic zone (weight 0.1), the base of transition zone (weight 0.2), the midpoint of the transition zone (weight 0.2), and a model with a long north-south segment at 123.8? W in the southern and central portions of the CSZ, with a dogleg to the northwest in the northern portion of the zone (weight 0.5). The latter model was derived from the approximate average longitude of the contour of the 30 km depth of the CSZ as modeled by Fluck et al. (1997). A global study of the maximum depth of thrust earthquakes on subduction zones by Tichelaar and Ruff (1993) indicated maximum depths of about 40 km for most of the subduction zones studied, although the Mexican subduction zone had a maximum depth of about 25 km (R. LaForge, pers. comm., 2006). The recent inversion of GPS data by McCaffrey et al. (2007) shows a significant amount of coupling (a coupling factor of 0.2-0.3) as far east as 123.8? West in some portions of the CSZ. Both of these lines of evidence lend support to the model with a north-south segment at 123.8? W.

  20. 21 CFR 892.1350 - Nuclear scanning bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear scanning bed. 892.1350 Section 892.1350...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1350 Nuclear scanning bed. (a) Identification. A nuclear scanning bed is an adjustable bed intended to support a patient during a nuclear...

  1. 21 CFR 880.5110 - Hydraulic adjustable hospital bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hydraulic adjustable hospital bed. 880.5110... Therapeutic Devices § 880.5110 Hydraulic adjustable hospital bed. (a) Identification. A hydraulic adjustable hospital bed is a device intended for medical purposes that consists of a bed with a hydraulic...

  2. 21 CFR 880.5110 - Hydraulic adjustable hospital bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydraulic adjustable hospital bed. 880.5110... Therapeutic Devices § 880.5110 Hydraulic adjustable hospital bed. (a) Identification. A hydraulic adjustable hospital bed is a device intended for medical purposes that consists of a bed with a hydraulic...

  3. 21 CFR 880.5110 - Hydraulic adjustable hospital bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hydraulic adjustable hospital bed. 880.5110... Therapeutic Devices § 880.5110 Hydraulic adjustable hospital bed. (a) Identification. A hydraulic adjustable hospital bed is a device intended for medical purposes that consists of a bed with a hydraulic...

  4. 21 CFR 880.5110 - Hydraulic adjustable hospital bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hydraulic adjustable hospital bed. 880.5110... Therapeutic Devices § 880.5110 Hydraulic adjustable hospital bed. (a) Identification. A hydraulic adjustable hospital bed is a device intended for medical purposes that consists of a bed with a hydraulic...

  5. 21 CFR 880.5110 - Hydraulic adjustable hospital bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hydraulic adjustable hospital bed. 880.5110... Therapeutic Devices § 880.5110 Hydraulic adjustable hospital bed. (a) Identification. A hydraulic adjustable hospital bed is a device intended for medical purposes that consists of a bed with a hydraulic...

  6. 21 CFR 892.1350 - Nuclear scanning bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear scanning bed. 892.1350 Section 892.1350...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1350 Nuclear scanning bed. (a) Identification. A nuclear scanning bed is an adjustable bed intended to support a patient during a nuclear...

  7. 21 CFR 892.1350 - Nuclear scanning bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear scanning bed. 892.1350 Section 892.1350...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1350 Nuclear scanning bed. (a) Identification. A nuclear scanning bed is an adjustable bed intended to support a patient during a nuclear...

  8. 21 CFR 892.1350 - Nuclear scanning bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear scanning bed. 892.1350 Section 892.1350...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1350 Nuclear scanning bed. (a) Identification. A nuclear scanning bed is an adjustable bed intended to support a patient during a nuclear...

  9. 21 CFR 892.1350 - Nuclear scanning bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear scanning bed. 892.1350 Section 892.1350...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1350 Nuclear scanning bed. (a) Identification. A nuclear scanning bed is an adjustable bed intended to support a patient during a nuclear...

  10. 21 CFR 880.5140 - Pediatric hospital bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pediatric hospital bed. 880.5140 Section 880.5140... Devices § 880.5140 Pediatric hospital bed. (a) Identification. A pediatric hospital bed is a device intended for medical purposes that consists of a bed or crib designed for the use of a pediatric...

  11. 21 CFR 880.5120 - Manual adjustable hospital bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual adjustable hospital bed. 880.5120 Section... Therapeutic Devices § 880.5120 Manual adjustable hospital bed. (a) Identification. A manual adjustable hospital bed is a device intended for medical purposes that consists of a bed with a manual...

  12. Dentin Caries Zones

    PubMed Central

    Pugach, M.K.; Strother, J.; Darling, C.L.; Fried, D.; Gansky, S.A.; Marshall, S.J.; Marshall, G.W.

    2009-01-01

    Caries Detector staining reveals 4 zones in dentin containing caries lesions, but characteristics of each zone are not well-defined. We therefore investigated the physical and microstructural properties of carious dentin in the 4 different zones to determine important differences revealed by Caries Detector staining. Six arrested dentin caries lesions and 2 normal controls were Caries-Detector-stained, each zone (pink, light pink, transparent, apparently normal) being analyzed by atomic force microscopy (AFM) imaging for microstructure, by AFM nano-indentation for mechanical properties, and by transverse digital microradiography (TMR) for mineral content. Microstructure changes, and nanomechanical properties and mineral content significantly decreased across zones. Hydrated elastic modulus and mineral content from normal dentin to pink Caries-Detector-stained dentin ranged from 19.5 [10.6-25.3] GPa to 1.6 [0.0-5.0] GPa and from 42.9 [39.8-44.6] vol% to 12.4 [9.1-14.2] vol%, respectively. Even the most demineralized pink zone contained considerable residual mineral. PMID:19131321

  13. Fault zone processes in mechanically layered mudrock and chalk

    NASA Astrophysics Data System (ADS)

    Ferrill, David A.; Evans, Mark A.; McGinnis, Ronald N.; Morris, Alan P.; Smart, Kevin J.; Wigginton, Sarah S.; Gulliver, Kirk D. H.; Lehrmann, Daniel; de Zoeten, Erich; Sickmann, Zach

    2017-04-01

    A 1.5 km long natural cliff outcrop of nearly horizontal Eagle Ford Formation in south Texas exposes northwest and southeast dipping normal faults with displacements of 0.01-7 m cutting mudrock, chalk, limestone, and volcanic ash. These faults provide analogs for both natural and hydraulically-induced deformation in the productive Eagle Ford Formation - a major unconventional oil and gas reservoir in south Texas, U.S.A. - and other mechanically layered hydrocarbon reservoirs. Fault dips are steep to vertical through chalk and limestone beds, and moderate through mudrock and clay-rich ash, resulting in refracted fault profiles. Steeply dipping fault segments contain rhombohedral calcite veins that cross the fault zone obliquely, parallel to shear segments in mudrock. The vertical dimensions of the calcite veins correspond to the thickness of offset competent beds with which they are contiguous, and the slip parallel dimension is proportional to fault displacement. Failure surface characteristics, including mixed tensile and shear segments, indicate hybrid failure in chalk and limestone, whereas shear failure predominates in mudrock and ash beds - these changes in failure mode contribute to variation in fault dip. Slip on the shear segments caused dilation of the steeper hybrid segments. Tabular sheets of calcite grew by repeated fault slip, dilation, and cementation. Fluid inclusion and stable isotope geochemistry analyses of fault zone cements indicate episodic reactivation at 1.4-4.2 km depths. The results of these analyses document a dramatic bed-scale lithologic control on fault zone architecture that is directly relevant to the development of porosity and permeability anisotropy along faults.

  14. Effectiveness of bed bug monitors for detecting and trapping bed bugs in apartments.

    PubMed

    Wang, Changlu; Tsai, Wan-Tien; Cooper, Richard; White, Jeffrey

    2011-02-01

    Bed bugs, Cimex lectularius L., are now considered a serious urban pest in the United States. Because they are small and difficult to find, there has been strong interest in developing and using monitoring tools to detect bed bugs and evaluate the results of bed bug control efforts. Several bed bug monitoring devices were developed recently, but their effectiveness is unknown. We comparatively evaluated three active monitors that contain attractants: CDC3000, NightWatch, and a home-made dry ice trap. The Climbup Insect Interceptor, a passive monitor (without attractants), was used for estimating the bed bug numbers before and after placing active monitors. The results of the Interceptors also were compared with the results of the active monitors. In occupied apartments, the relative effectiveness of the active monitors was: dry ice trap > CDC3000 > NightWatch. In lightly infested apartments, the Interceptor (operated for 7 d) trapped similar number of bed bugs as the dry ice trap (operated for 1 d) and trapped more bed bugs than CDC3000 and NightWatch (operated for 1 d). The Interceptor was also more effective than visual inspections in detecting the presence of small numbers of bed bugs. CDC3000 and the dry ice trap operated for 1 d were equally as effective as the visual inspections for detecting very low level of infestations, whereas 1-d deployment of NightWatch detected significantly lower number of infestations compared with visual inspections. NightWatch was designed to be able to operate for several consecutive nights. When operated for four nights, NightWatch trapped similar number of bed bugs as the Interceptors operated for 10 d after deployment of NightWatch. We conclude these monitors are effective tools in detecting early bed bug infestations and evaluating the results of bed bug control programs.

  15. The Significance of Cross-Bedded Surge Deposits

    NASA Astrophysics Data System (ADS)

    Burgisser, A.; Gardner, J. E.

    2003-12-01

    of density because the force needed to rotate a clast at rest varies linearly with density but with the fourth power of the diameter. As a result, traction-dominated transport sorts clasts only by size, reinforcing the coarser end of the density sorting of the transport system by remobilizing and mixing finer grains while leaving the coarse fraction. Coarse-grain layers well sorted in density are thus composed of clasts traveling successively through the transport system and the traction bed. Those coarse layers retain a memory of the large-scale transport system, whereas boundary layer processes control the sorting of the finer grain sizes. The general absence of density sorting within zones in transition with massive deposit is consistent with an increasing control of traction-dominated transport across the transition. Dunes appear to form around a nucleus of clasts creating a small protrusion and grow layer by layer via accretion. This feedback growth indifferently produces prograde or retrograde dune crests. The cascading distribution of dunes suggests that the smaller dunes are built in response to the emplacement of a large dune. Consequently, dunes originate from local disturbances of the boundary layer that is rapidly attenuated downstream. If this cascading process is repeated, the original dune string is likely to be reworked into a complex array of dune forms. The shapes and sizes of dunes thus record little information on the large-scale dynamics of the surge.

  16. DNA profiling of trace DNA recovered from bedding.

    PubMed

    Petricevic, Susan F; Bright, Jo-Anne; Cockerton, Sarah L

    2006-05-25

    Trace DNA is often detected on handled items and worn clothing examined in forensic laboratories. In this study, the potential transfer of trace DNA to bedding by normal contact, when an individual sleeps in a bed, is examined. Volunteers slept one night on a new, lower bed sheet in their own bed and one night in a bed foreign to them. Samples from the sheets were collected and analysed by DNA profiling. The results indicate that the DNA profile of an individual can be obtained from bedding after one night of sleeping in a bed. The DNA profile of the owner of the bed could also be detected in the foreign bed experiments. Since mixed DNA profiles can be obtained from trace DNA on bedding, caution should be exercised when drawing conclusions from DNA profiling results obtained from such samples. This transfer may have important repercussions in sexual assault investigations.

  17. Identification of potential artificial groundwater recharge zones in Northwestern Saudi Arabia using GIS and Boolean logic

    NASA Astrophysics Data System (ADS)

    Zaidi, Faisal K.; Nazzal, Yousef; Ahmed, Izrar; Naeem, Muhammad; Jafri, Muhammad Kamran

    2015-11-01

    Identifying potential groundwater recharge zones is a pre-requisite for any artificial recharge project. The present study focuses on identifying the potential zones of Artificial Groundwater Recharge (AGR) in Northwestern Saudi Arabia. Parameters including slope, soil texture, vadose zone thickness, groundwater quality (TDS) and type of water bearing formation were integrated in a GIS environment using Boolean logic. The results showed that 17.90% of the total studied area is suitable for AGR. The identified zones were integrated with the land use/land cover map to avoid agricultural and inhabited lands which reduced the total potential area to 14.24%. Geomorphologically the wadi beds are the most suitable sites for recharge. On the basis of the potential AGR zones closeness to the available recharge water supply (rain water, desalinated sea water and treated waste water) the potential zones were classified as Category A (high priority) and Category B (low priority).

  18. Bed Stability and Debris Flow Erosion: A Dynamic "Shields Criterion" Associated with Bed Structure

    NASA Astrophysics Data System (ADS)

    Longjas, A.; Hill, K. M.

    2015-12-01

    Debris flows are mass movements that play an important role in transporting sediment from steep uplands to rivers at lower slopes. As the debris flow moves downstream, it entrains materials such as loose boulders, gravel, sand and mud deposited locally by shorter flows such as slides and rockfalls. To capture the conditions under which debris flows entrain bed sediment, some models use something akin to the Shields' criterion and an excess shear stress of the flow. However, these models typically neglect granular-scale effects in the bed which can modify the conditions under which a debris flow is erosional or depositional. For example, it is well known that repeated shearing causes denser packing in loose dry soils, which undoubtedly changes their resistance to shear. Here, we present laboratory flume experiments showing that the conditions for entrainment by debris flows is significantly dependent on the aging of an erodible bed even for narrowly distributed spherical particles. We investigate this quantitatively using particle tracking measurements to quantify instantaneous erosion rates and the evolving bed structure or "fabric". With progressive experiments we find a signature that emerges in the bed fabric that is correlated with an increasing apparent "fragility" of the bed. Specifically, a system that is originally depositional may become erosional after repeated debris flow events, and an erodible bed becomes increasingly erodible with repeated flows. We hypothesize that related effects of bed aging at the field scale may be partly responsible for the increasing destructiveness of secondary flows of landslides and debris flows.

  19. Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

    NASA Astrophysics Data System (ADS)

    Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

    Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

  20. Coal fired fluid bed module for a single elevation style fluid bed power plant

    DOEpatents

    Waryasz, Richard E.

    1979-01-01

    A fluidized bed for the burning of pulverized fuel having a specific waterwall arrangement that comprises a structurally reinforced framework of wall tubes. The wall tubes are reversely bent from opposite sides and then bonded together to form tie rods that extend across the bed to support the lateral walls thereof.

  1. Nature of natural gas in anomalously thick coal beds, Powder River basin, Wyoming

    SciTech Connect

    Rice, D.D.; Flores, R.M. )

    1989-09-01

    Anomalously thick coal beds (as much as 250 ft thick) occur in the Paleocene Tongue River Member of the Fort Union Formation in the Powder River basin, Wyoming. These laterally discontinuous coal beds were deposited in raised, ombrotrophic peat bogs of fluvial environments. The coal beds include the Anderson-Canyon, Wyodak-Anderson, and Big George zones in the Powder River-Recluse area, Gillette area, and central part of the basin, respectively. The coal resources in these areas are approximately 155 billion short tons. The average maceral composition of the coals is 88% huminite (vitrinite), 5% liptinite, and 7% inertinite. The coals vary in rank from subbituminous C to A (R{sub 0} values of 0.4 to 0.5%). Natural gas desorbed and produced from the coal beds and adjacent sandstones is composed mainly of methane with lesser amounts of CO{sub 2} (less than 10%). The methane is isotopically light ({delta}{sup 13}C{sup 1} values of {minus}56.7 to {minus}60.9%). Based on the chemical and isotopic composition of the gases and on the low rank of the coals, the gases are interpreted to be microbial in origin: they were generated by anaerobic bacteria that broke down the coals at low temperatures, prior to the main phase of thermogenic methane generation by devolatilization. The adsorbed amounts of methane-rich microbial gas per unit of coal in the Powder River basin are relatively low compared to amounts of thermogenic coal-bed gases from other basins. However, the total coal-bed gas resource is considered to be large (as much as several trillion cubic feet) because of the vast coal resources.

  2. Monolithic Hydrogen Peroxide Catalyst Bed Development

    NASA Technical Reports Server (NTRS)

    Ponzo, J. B.

    2003-01-01

    With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

  3. The thermal conductivity of beds of spheres

    SciTech Connect

    McElroy, D.L.; Weaver, F.J.; Shapiro, M.; Longest, A.W.; Yarbrough, D.W.

    1987-01-01

    The thermal conductivities (k) of beds of solid and hollow microspheres were measured using two radial heat flow techniques. One technique provided k-data at 300 K for beds with the void spaces between particles filled with argon, nitrogen, or helium from 5 kPa to 30 MPa. The other technique provided k-data with air at atmospheric pressure from 300 to 1000 K. The 300 K technique was used to study bed systems with high k-values that can be varied by changing the gas type and gas pressure. Such systems can be used to control the operating temperature of an irradiation capsule. The systems studied included beds of 500 ..mu..m dia solid Al/sub 2/O/sub 3/, the same Al/sub 2/O/sub 3/ spheres mixed with spheres of silica--alumina or with SiC shards, carbon spheres, and nickel spheres. Both techniques were used to determine the k-value of beds of hollow spheres with solid shells of Al/sub 2/O/sub 3/, Al/sub 2/O/sub 3//center dot/7 w/o Cr/sub 2/O/sub 3/, and partially stabilized ZrO/sub 2/. The hollow microspheres had diameters from 2100 to 3500 ..mu..m and wall thicknesses from 80 to 160 ..mu..m. 12 refs., 7 figs., 4 tabs.

  4. An innovative vibration fluidized bed ash cooler

    SciTech Connect

    Duan, Y.; Zhang, M.; Liu, A.; Yao, Z.; Tang, H.; Liu, Q.

    1999-07-01

    With the ever-increasing versatility, scaling up and commercialization of coal-fired fluidized bed boiler technologies, it has become more and more important to improve the technique of draining bed ash from bubbling or circulating fluidized bed boilers. Choosing an ash cooler is a good way but highly stable and reliable system is hard to find for a massive ash flow rate having a broad particle size distributions. An innovative technique known as Vibration Fluidized Bed Ash Cooler (VFBAC) is proposed in this paper. It can drain bottom ash at a high temperature from FB or CFB boilers continuously and controllably. In this device, air used for cooling can be used as combustion-aided air or coal spreading air. The hot ash is cooled by the air to a temperature which it can be transported easily and safely by conventional technology. Meanwhile, an industrial apparatus utilizing the new technology was manufactured and used in a 35 t/h bubbling FB boiler. For the purpose of detecting residence time distribution of wide-sieved bed materials in this ash cooler systematically, advantage was taken of a new approach for physical quality discrimination. Investigations into the hydrodynamic characteristics of the gas-solid two-phase flows and theoretical analyses on hot operational performance were carried out. The results show that heat recovery efficiency of the ash cooler reaches 85% greater when operating at a ratio of air to ash of 1.5{approximately}2.5 Nm{sup 3}/kg.

  5. Grain Exchange Probabilities Within a Gravel Bed

    NASA Astrophysics Data System (ADS)

    Haschenburger, J.

    2008-12-01

    Sediment transfers in gravel-bed rivers involve the vertical exchange of sediments during floods. These exchanges regulate the virtual velocity of sediment and bed material texture. This study describes general tendencies in the vertical exchange of gravels within the substrate that result from multiple floods. Empirical observations come from Carnation Creek, a small gravel-bed river with large woody debris located on the west coast of Vancouver Island, British Columbia. Frequent floods and the relatively limited armor layer facilitate streambed activity and relatively high bedload transport rates, typically under partial sediment transport conditions. Over 2000 magnetically tagged stones, ranging in size from 16 to 180 mm, were deployed on the bed surface between 1991 and 1992. These tracers have been recovered 10 times over 12 flood seasons to quantify their vertical position in the streambed. For analysis, the bed is divided into layers based on armor layer thickness. Once tracers are well mixed within the streambed, grains in the surface layer are most likely to be mixed into the subsurface, while subsurface grains are most likely to persist within the subsurface. Fractional exchange probabilities approach size independence when the most active depth of the substrate is considered. Overall these results highlight vertical mixing as an important process in the dispersion of gravels.

  6. Bed material agglomeration during fluidized bed combustion. Technical progress report, September 30, 1992--December 31, 1992

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.

    1993-02-01

    The purpose of this project is to determine the physical and chemical reactions which led to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. Survey of industrial-scale fluidized bed combustors is being conducted to determine the occurrence of bed agglomeration and the circumstances under which agglomeration took place. This task should be finished by the end of February. Samples of bed material, agglomerate material, and boiler deposits are being requested from boiler operators as part of the survey. Once received, these sample will be analyzed to determine chemical and mineralogic composition. The bulk chemical determination will be performed using x-ray fluorescence and inductively coupled plasma-optical emission (ICP). Mineralogy will be detected by x-ray diffraction (XRD). Chemical and mineral reactions will be determined by scanning electron microscopy, optical microscopy, and electron microprobe.

  7. Measurement of powder bed density in powder bed fusion additive manufacturing processes

    NASA Astrophysics Data System (ADS)

    Jacob, G.; Donmez, A.; Slotwinski, J.; Moylan, S.

    2016-11-01

    Many factors influence the performance of additive manufacturing (AM) processes, resulting in a high degree of variation in process outcomes. Therefore, quantifying these factors and their correlations to process outcomes are important challenges to overcome to enable widespread adoption of emerging AM technologies. In the powder bed fusion AM process, the density of the powder layers in the powder bed is a key influencing factor. This paper introduces a method to determine the powder bed density (PBD) during the powder bed fusion (PBF) process. A complete uncertainty analysis associated with the measurement method was also described. The resulting expanded measurement uncertainty, U PBD (k  =  2), was determined as 0.004 g · cm-3. It was shown that this expanded measurement uncertainty is about three orders of magnitude smaller than the typical powder bed density. This method enables establishing correlations between the changes in PBD and the direction of motion of the powder recoating arm.

  8. Modeling and fixed bed column adsorption of As(V) on laterite soil.

    PubMed

    Maji, Sanjoy K; Pal, Anjali; Pal, Tarasankar; Adak, Asok

    2007-09-01

    Laterite soil, an abundant locally available natural adsorbent, has been evaluated for As(V) removal from aqueous solutions in column mode operation. The column studies were conducted using columns of 10, 20, 30 cm bed depth with 2 cm internal diameter. Initial As(V) concentration was 0.5 mg/L and flow rate was 7.75 mL/min. Bohart and Adams sorption model was employed for the determination of different parameters like height of exchange zone, adsorption rate, time required for exchange zone to move, and the adsorption capacity. Effect of flow rate and initial concentration was studied. The adsorption capacity of the laterite soil for 0.5 mg/L of As(V) was found to be 62.32 mg/L, and the adsorption rate constant was 1.0911 L/mg h for the minimum bed depth of 8.47 cm. The column was designed by the BDST model. Freundlich isotherm model was used to compare the theoretical and experimental breakthrough profile in the dynamic process. The bed saturation obtained was 36-80%. Regeneration of the exhausted column was possible with 1M NaOH.

  9. Paleokarstic phenomena of the Lower Ordovician red bed sequences of the Arbuckle group, southern Oklahoma

    SciTech Connect

    Musselman, J.L. )

    1991-06-01

    Oil and gas production has been reported recently from paleokarstic Arbuckle reservoirs in the Ardmore and Arkoma basin. The West Spring Creek and the Kindblade formations apparently exhibit karstic features. The most extensive surface exposure of these formations is on the southern flank of the Arbuckle anticline along Interstate 35 north of Ardmore, Oklahoma. The lithology is predominantly limestone, ranging from argillaceous mudstone to oolitic and/or bioclastic grainstones. However, minor amounts of sandstone were also observed.These lithologies are characteristic of various peritidal facies. Of particular interest in this outcrop are three distinct red bed zones. Although the zones are part of the repetitive shallowing-upward cycles that characterize the West Spring Creek Formation, ample evidence suggests the red beds represent subaerial exposure surfaces where karstification took place. Many of the thin bedded, rubbly mudstones and wackestones actually represent varieties of breccia commonly associated with karst. Collapse and crackle breccia are most commonly observed. Small solution channels and other vugs are usually completely occluded by calcite cement. However, solution cavities or vugs with diameters larger than 10 cm (3.9 in.) are lined with drusy calcite. Hematite-impregnated sediment occurs as thinly laminated infilling of solution vugs and cavities and also acts as a cementing agent of collapse breccias. Preliminary evidence suggests that karstification processes were active during Arbuckle deposition.

  10. Control of a Circulating Fluidized Bed

    SciTech Connect

    Shim, Hoowang; Rickards, Gretchen; Famouri, Parviz; Turton, Richard; Sams, W. Neal; Koduro, Praveen; Patankar, Amol; Davari, Assad; Lawson, Larry; Boyle, Edward J.

    2001-11-06

    Two methods for optimally controlling the operation of a circulating fluidized bed are being investigated, neural network control and Kalman filter control. The neural network controls the solids circulation rate by adjusting the flow of move air in the non-mechanical valve. Presented is the method of training the neural network from data generated by the circulating fluidized bed (CFB), the results of a sensitivity study indicating that adjusting the move air can control solids flow, and the results of controlling solids circulation rate. The Kalman filter approach uses a dynamic model and a measurement model of the standpipe section of the CFB. Presented are results showing that a Kalman filter can successfully find the standpipe bed height.

  11. FPGA Based Reconfigurable ATM Switch Test Bed

    NASA Technical Reports Server (NTRS)

    Chu, Pong P.; Jones, Robert E.

    1998-01-01

    Various issues associated with "FPGA Based Reconfigurable ATM Switch Test Bed" are presented in viewgraph form. Specific topics include: 1) Network performance evaluation; 2) traditional approaches; 3) software simulation; 4) hardware emulation; 5) test bed highlights; 6) design environment; 7) test bed architecture; 8) abstract sheared-memory switch; 9) detailed switch diagram; 10) traffic generator; 11) data collection circuit and user interface; 12) initial results; and 13) the following conclusions: Advances in FPGA make hardware emulation feasible for performance evaluation, hardware emulation can provide several orders of magnitude speed-up over software simulation; due to the complexity of hardware synthesis process, development in emulation is much more difficult than simulation and requires knowledge in both networks and digital design.

  12. Field assessment of alternative bed-load transport estimators

    USGS Publications Warehouse

    Gaeuman, G.; Jacobson, R.B.

    2007-01-01

    Measurement of near-bed sediment velocities with acoustic Doppler current profilers (ADCPs) is an emerging approach for quantifying bed-load sediment fluxes in rivers. Previous investigations of the technique have relied on conventional physical bed-load sampling to provide reference transport information with which to validate the ADCP measurements. However, physical samples are subject to substantial errors, especially under field conditions in which surrogate methods are most needed. Comparisons between ADCP bed velocity measurements with bed-load transport rates estimated from bed-form migration rates in the lower Missouri River show a strong correlation between the two surrogate measures over a wide range of mild to moderately intense sediment transporting conditions. The correlation between the ADCP measurements and physical bed-load samples is comparatively poor, suggesting that physical bed-load sampling is ineffective for ground-truthing alternative techniques in large sand-bed rivers. Bed velocities measured in this study became more variable with increasing bed-form wavelength at higher shear stresses. Under these conditions, bed-form dimensions greatly exceed the region of the bed ensonified by the ADCP, and the magnitude of the acoustic measurements depends on instrument location with respect to bed-form crests and troughs. Alternative algorithms for estimating bed-load transport from paired longitudinal profiles of bed topography were evaluated. An algorithm based on the routing of local erosion and deposition volumes that eliminates the need to identify individual bed forms was found to give results similar to those of more conventional dune-tracking methods. This method is particularly useful in cases where complex bed-form morphology makes delineation of individual bed forms difficult. ?? 2007 ASCE.

  13. Combustion characteristics of different parts of corn straw and NO formation in a fixed bed.

    PubMed

    Zhao, Wei; Li, Zhengqi; Wang, Dawei; Zhu, Qunyi; Sun, Rui; Meng, Baihong; Zhao, Guangbo

    2008-05-01

    Experiments with five samples of corn straw were carried out on a one-dimensional bench combustion test rig. The bed temperature distribution and the mass loss of fuel and gas components such as O2, CO, CO2 and NO were measured in the bed. The combustion of corn straw occurred in two stages, ignition front propagation and char oxidation. The average burning rate increased with an increase in the primary air flow until a critical point was reached, beyond which a further increase in the primary air flow resulted in a decreased burning rate. The mean concentration of NO reached a minimum value and then increased with increased primary air flow. The time taken for the drying front to reach the bottom of the bed was 800 s, 700 s, and 500 s; the temperatures in the high bed temperature zones were 900-935 degrees C, 800-850 degrees C and 700-743 degrees C; and the maximum concentrations of NO were 725 ppmv, 1287 ppmv, and 2730 ppmv, for whole corn stalks, hollow corn stalks and flaked corn stalks, respectively. The maximum concentrations of CO and NO were quite different between samples. There was only one peak in the distribution of NO concentration for sample B, but there were two peaks for whole corn stalks and sample A.

  14. Fixed bed column study for heavy metal removal using phosphate treated rice husk.

    PubMed

    Mohan, S; Sreelakshmi, G

    2008-05-01

    This paper reports the results of the study on the performance of low-cost adsorbent such as raw rice husk (RRH) and phosphate treated rice husk (PRH) in removing the heavy metals such as lead, copper, zinc and manganese. The adsorbent materials adopted were found to be an efficient media for the removal of heavy metals in continuous mode using fixed bed column. The column studies were conducted with 10 mg/l of individual and combined metal solution with a flow rate of 20 ml/min with different bed depths such as 10, 20 and 30 cm. The breakthrough time was also found to increase from 1.3 to 3.5 h for Pb(II), 4.0 to 9.0 h for Cu(II), 12.5 to 25.4h for Zn(II) and 3.0 to 11.3 h for Mn(II) with increase in bed height from 10 to 30 cm for PRH. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. were calculated. It is found that the adsorption capacity and adsorption rate constant were increased and the minimum column bed depth required was reduced when the rice husk is treated with phosphate, when compared with that of RRH.

  15. Aperture modulated, translating bed total body irradiation

    SciTech Connect

    Hussain, Amjad; Villarreal-Barajas, Jose Eduardo; Dunscombe, Peter; Brown, Derek W.

    2011-02-15

    Purpose: Total body irradiation (TBI) techniques aim to deliver a uniform radiation dose to a patient with an irregular body contour and a heterogeneous density distribution to within {+-}10% of the prescribed dose. In the current article, the authors present a novel, aperture modulated, translating bed TBI (AMTBI) technique that produces a high degree of dose uniformity throughout the entire patient. Methods: The radiation beam is dynamically shaped in two dimensions using a multileaf collimator (MLC). The irregular surface compensation algorithm in the Eclipse treatment planning system is used for fluence optimization, which is performed based on penetration depth and internal inhomogeneities. Two optimal fluence maps (AP and PA) are generated and beam apertures are created to deliver these optimal fluences. During treatment, the patient/phantom is translated on a motorized bed close to the floor (source to bed distance: 204.5 cm) under a stationary radiation beam with 0 deg. gantry angle. The bed motion and dynamic beam apertures are synchronized. Results: The AMTBI technique produces a more homogeneous dose distribution than fixed open beam translating bed TBI. In phantom studies, the dose deviation along the midline is reduced from 10% to less than 5% of the prescribed dose in the longitudinal direction. Dose to the lung is reduced by more than 15% compared to the unshielded fixed open beam technique. At the lateral body edges, the dose received from the open beam technique was 20% higher than that prescribed at umbilicus midplane. With AMTBI the dose deviation in this same region is reduced to less than 3% of the prescribed dose. Validation of the technique was performed using thermoluminescent dosimeters in a Rando phantom. Agreement between calculation and measurement was better than 3% in all cases. Conclusions: A novel, translating bed, aperture modulated TBI technique that employs dynamically shaped MLC defined beams is shown to improve dose uniformity

  16. Exercise countermeasures for bed-rest deconditioning

    NASA Technical Reports Server (NTRS)

    Greenleaf, John (Editor)

    1993-01-01

    The purpose for this 30-day bed rest study was to investigate the effects of short-term, high intensity isotonic and isokinetic exercise training on maintenance of working capacity (peak oxygen uptake), muscular strength and endurance, and on orthostatic tolerance, posture and gait. Other data were collected on muscle atrophy, bone mineralization and density, endocrine analyses concerning vasoactivity and fluid-electrolyte balance, muscle intermediary metabolism, and on performance and mood of the subjects. It was concluded that: The subjects maintained a relatively stable mood, high morale, and high esprit de corps throughout the study. Performance improved in nearly all tests in almost all the subjects. Isotonic training, as opposed to isokinetic exercise training, was associated more with decreasing levels of psychological tension, concentration, and motivation; and improvement in the quality of sleep. Working capacity (peak oxygen uptake) was maintained during bed rest with isotonic exercise training; it was not maintained with isokinetic or no exercise training. In general, there was no significant decrease in strength or endurance of arm or leg muscles during bed rest, in spite of some reduction in muscle size (atrophy) of some leg muscles. There was no effect of isotonic exercise training on orthostasis, since tilt-table tolerance was reduced similarly in all three groups following bed rest. Bed rest resulted in significant decreases of postural stability and self-selected step length, stride length, and walking velocity, which were not influenced by either exercise training regimen. Most pre-bed rest responses were restored by the fourth day of recovery.

  17. Loading and Unloading Finishing Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    PubMed Central

    Garcia, Arlene; McGlone, John J.

    2014-01-01

    Simple Summary Current guidelines suggest the use of ramps below 20 degrees to load and unload pigs; however, they do not suggest the use of any specific bedding. Bedding types (nothing, feed, sand, wood shavings, and hay) were tested with finishing pigs (70–120 kg) to determine which was most effective in reducing slips, falls, and vocalizations at three ramp angles, two moisture levels, over two seasons. Slips, falls, and vocalizations were summed to establish a scoring system for the types of beddings. Heart rate and the total time it took to load and unload pigs, increased as the slope increased. Bedding, bedding moisture, season, and ramp slope interacted to impact the total time it took for finishing pigs to load and unload the ramp. Selection of the best bedding depends on ramp slope, season, and wetness of bedding. Abstract The use of non-slip surfaces during loading and unloading of finishing pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps with a slope below 20 degrees to load and unload pigs. However, the total time it takes to load and unload animals and slips, falls, and vocalizations are a welfare concern. Three ramp angles (0, 10 or 20 degrees), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding, >50% moisture) over two seasons (>23.9 °C summer, <23.9 °C winter) were assessed for slips/falls/vocalizations (n = 2400 pig observations) and analyzed with a scoring system. The use of bedding during summer or winter played a role in the total time it took to load and unload the ramp (p < 0.05). Bedding, bedding moisture, season, and slope significantly interacted to impact the total time to load and unload finishing pigs (p < 0.05). Heart rate and the total time it took to load and unload the ramp increased as the slope of the ramp increased (p < 0.05). Heart rates were higher during the

  18. Phase 1 Methyl Iodide Deep-Bed Adsorption Tests

    SciTech Connect

    Soelberg, Nick; Watson, Tony

    2014-08-22

    are soluble in NaOH scrubbing solution for iodine analysis. But when NOx and H2O are not present, then the majority of the uncaptured iodine exiting iodine-laden sorbent is in the form of methyl iodide. Methyl iodide adsorption efficiencies have been high enough so that initial DFs exceed 1,000 to 10,000. The methyl iodide mass transfer zone depths are estimated at 4-8 inches, possibly deeper than mass transfer zone depths estimated for I2 adsorption on AgZ. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption under various conditions specified in the methyl iodide test plan, and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  19. Channel Change and Bed-Material Transport in the Lower Chetco River, Oregon

    USGS Publications Warehouse

    Wallick, J. Rose; Anderson, Scott W.; Cannon, Charles; O'Connor, Jim E.

    2010-01-01

    The lower Chetco River is a wandering gravel-bed river flanked by abundant and large gravel bars formed of coarse bed-material sediment. Since the early twentieth century, the large gravel bars have been a source of commercial aggregate for which ongoing permitting and aquatic habitat concerns have motivated this assessment of historical channel change and sediment transport rates. Analysis of historical channel change and bed-material transport rates for the lower 18 kilometers shows that the upper reaches of the study area are primarily transport zones, with bar positions fixed by valley geometry and active bars mainly providing transient storage of bed material. Downstream reaches, especially near the confluence of the North Fork Chetco River, are zones of active sedimentation and channel migration. Multiple analyses, supported by direct measurements of bedload during winter 2008-09, indicate that since 1970 the mean annual flux of bed material into the study reach has been about 40,000-100,000 cubic meters per year. Downstream tributary input of bed-material sediment, probably averaging 5-30 percent of the influx coming into the study reach from upstream, is approximately balanced by bed-material attrition by abrasion. Probably little bed material leaves the lower river under natural conditions, with most net influx historically accumulating in wider and more dynamic reaches, especially near the North Fork Chetco River confluence, 8 kilometers upstream from the Pacific Ocean. The year-to-year flux, however, varies tremendously. Some years may have less than 3,000 cubic meters of bed material entering the study area; by contrast, some high-flow years, such as 1982 and 1997, likely have more than 150,000 cubic meters entering the reach. For comparison, the estimated annual volume of gravel extracted from the lower Chetco River for commercial aggregate during 2000-2008 has ranged from 32,000 to 90,000 cubic meters and averaged about 59,000 cubic meters per year

  20. Channel Change and Bed-Material Transport in the Lower Chetco River, Oregon

    USGS Publications Warehouse

    Wallick, J. Rose; Anderson, Scott W.; Cannon, Charles; O'Connor, Jim E.

    2009-01-01

    The lower Chetco River is a wandering gravel-bed river flanked by abundant and large gravel bars formed of coarse bed-material sediment. The large gravel bars have been a source of commercial aggregate since the early twentieth century for which ongoing permitting and aquatic habitat concerns have motivated this assessment of historical channel change and sediment transport rates. Analysis of historical channel change and bed-material transport rates for the lower 18 kilometers show that the upper reaches of the study area are primarily transport zones, with bar positions fixed by valley geometry and active bars mainly providing transient storage of bed material. Downstream reaches, especially near the confluence of the North Fork Chetco River, have been zones of active sedimentation and channel migration. Multiple analyses, supported by direct measurements of bedload during winter 2008-09, indicate that since 1970 the mean annual flux of bed material into the study reach has been about 40,000-100,000 cubic meters per year. Downstream tributary input of bed-material sediment, probably averaging 5-30 percent of the influx coming into the study reach from upstream, is approximately balanced by bed-material attrition by abrasion. Probably very little bed material leaves the lower river under natural conditions, with most of the net influx historically accumulating in wider and more dynamic reaches, especially near the North Fork Chetco River confluence, 8 kilometers upstream from the Pacific Ocean. The year-to-year flux, however, varies tremendously. Some years probably have less than 3,000 cubic meters of bed-material entering the study area; by contrast, some high-flow years, such as 1982 and 1997, likely have more than 150,000 cubic meters entering the reach. For comparison, the estimated annual volume of gravel extracted from the lower Chetco River for commercial aggregate during 2000-2008 has ranged from 32,000 to 90,000 cubic meters and averaged about 59

  1. Acoustic detectability of squid egg beds

    NASA Astrophysics Data System (ADS)

    Foote, Kenneth G.; Hanlon, Roger T.; Henry, Annette E.; Hochstaedter, Alfred; Kvitek, Rikk; Sullivan, Deidre; Yogozawa, Yuko

    2003-10-01

    Egg beds of the market squid (Loligo opalescens) on the bottom of Monterey Bay seem to have been detected by means of sidescan sonar at 420 kHz. Evidence for this is presented in the form of sidescan sonar images and egg-bed distribution maps from the same area, as prepared from camera surveys by scuba divers. The general detectability issue is also considered, with specific reference made to preliminary physical measurements performed on two egg capsules. [Work supported by Sea Grant.

  2. Cardiac atrophy after bed rest and spaceflight

    NASA Technical Reports Server (NTRS)

    Perhonen, M. A.; Franco, F.; Lane, L. D.; Buckey, J. C.; Blomqvist, C. G.; Zerwekh, J. E.; Peshock, R. M.; Weatherall, P. T.; Levine, B. D.

    2001-01-01

    Cardiac muscle adapts well to changes in loading conditions. For example, left ventricular (LV) hypertrophy may be induced physiologically (via exercise training) or pathologically (via hypertension or valvular heart disease). If hypertension is treated, LV hypertrophy regresses, suggesting a sensitivity to LV work. However, whether physical inactivity in nonathletic populations causes adaptive changes in LV mass or even frank atrophy is not clear. We exposed previously sedentary men to 6 (n = 5) and 12 (n = 3) wk of horizontal bed rest. LV and right ventricular (RV) mass and end-diastolic volume were measured using cine magnetic resonance imaging (MRI) at 2, 6, and 12 wk of bed rest; five healthy men were also studied before and after at least 6 wk of routine daily activities as controls. In addition, four astronauts were exposed to the complete elimination of hydrostatic gradients during a spaceflight of 10 days. During bed rest, LV mass decreased by 8.0 +/- 2.2% (P = 0.005) after 6 wk with an additional atrophy of 7.6 +/- 2.3% in the subjects who remained in bed for 12 wk; there was no change in LV mass for the control subjects (153.0 +/- 12.2 vs. 153.4 +/- 12.1 g, P = 0.81). Mean wall thickness decreased (4 +/- 2.5%, P = 0.01) after 6 wk of bed rest associated with the decrease in LV mass, suggesting a physiological remodeling with respect to altered load. LV end-diastolic volume decreased by 14 +/- 1.7% (P = 0.002) after 2 wk of bed rest and changed minimally thereafter. After 6 wk of bed rest, RV free wall mass decreased by 10 +/- 2.7% (P = 0.06) and RV end-diastolic volume by 16 +/- 7.9% (P = 0.06). After spaceflight, LV mass decreased by 12 +/- 6.9% (P = 0.07). In conclusion, cardiac atrophy occurs during prolonged (6 wk) horizontal bed rest and may also occur after short-term spaceflight. We suggest that cardiac atrophy is due to a physiological adaptation to reduced myocardial load and work in real or simulated microgravity and demonstrates the plasticity

  3. Enzymatic Catalytic Beds For Oxidation Of Alcohols

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.; Schussel, Leonard J.

    1993-01-01

    Modules containing beds of enzymatic material catalyzing oxidation of primary alcohols and some other organic compounds developed for use in wastewater-treatment systems of future spacecraft. Designed to be placed downstream of multifiltration modules, which contain filters and sorbent beds removing most of non-alcoholic contaminants but fail to remove significant amounts of low-molecular-weight, polar, nonionic compounds like alcohols. Catalytic modules also used on Earth to oxidize primary alcohols and other compounds in wastewater streams and industrial process streams.

  4. South Africa slashes pebble-bed cash

    NASA Astrophysics Data System (ADS)

    Cartlidge, Edwin

    2010-04-01

    A novel modular technology that promised to make nuclear power cheaper and safer has suffered a serious blow following withdrawal of support from the South African government. It decided not to renew funding for the pebble-bed modular reactor beyond 31 March this year following a lack of interest from other investors and no customers for its product. The company developing the reactor concept - Pebble Bed Modular Reactor Ltd (PBMR) - is to axe three-quarters of its roughly 800 staff and its chief executive has resigned.

  5. Lake bed classification using acoustic data

    USGS Publications Warehouse

    Yin, Karen K.; Li, Xing; Bonde, John; Richards, Carl; Cholwek, Gary

    1998-01-01

    As part of our effort to identify the lake bed surficial substrates using remote sensing data, this work designs pattern classifiers by multivariate statistical methods. Probability distribution of the preprocessed acoustic signal is analyzed first. A confidence region approach is then adopted to improve the design of the existing classifier. A technique for further isolation is proposed which minimizes the expected loss from misclassification. The devices constructed are applicable for real-time lake bed categorization. A mimimax approach is suggested to treat more general cases where the a priori probability distribution of the substrate types is unknown. Comparison of the suggested methods with the traditional likelihood ratio tests is discussed.

  6. The use of bed distribution and service population indexes for hospital bed allocation.

    PubMed Central

    Bay, K S; Nestman, L J

    1984-01-01

    To provide an empirical base for bed reallocation within a hospital planning jurisdiction in Canada, this article proposes a population-based method to measure the distribution of acute care beds for each district and the service load for each hospital. The measure for the bed distribution (BDI) is the number of beds per 1,000 age-sex-adjusted number of residents in a district, while the service load of a hospital is measured by the number of persons being served per bed (SPI). The number of beds allocated to each district, or the number of persons served by each hospital, was estimated by applying the hospital service population model, which employs both relevance- and commitment-index methods. The method thus proposed was applied to Alberta data. It appears that both BDI and SPI measures are stable across the variation of methods or data sources, yet sensitive enough to detect changes over the years. Using these indexes, potentially over- or underbedded districts and over- or underloaded hospitals can be identified for further investigation so that possible reallocation of acute care beds among the hospitals may take place. PMID:6547418

  7. From Modern Push-Button Hospital-beds to 20th Century Mechatronic Beds: A Review

    NASA Astrophysics Data System (ADS)

    Ghersi, I.; Mariño, M.; Miralles, M. T.

    2016-04-01

    The aim of this work is to present the different aspects of modern high complexity electric beds of the period 1940 until 2000 exclusively. The chronology of the product has been strictly divided into three big stages: electric and semi-electric beds (until the 90’s), mechatronic beds (90’s until 2000) and, mechatronic intelligent beds of the last 15 years. The latter are not considered in this work due to the extension for its analysis. The justification for classifying the product is presented under the concepts of medical, assistive and mobility devices. Relevant aspects of common immobility problems of the different types of patients for which the beds are mainly addressed are shown in detail. The basic functioning of the patient’s movement generator and the implementation of actuators, together with IT programs, specific accessories and connectivity means and network-communication shown in this work, were those that gave origin to current mechatronic beds. We present the historical evolution of high complexity electric beds by illustrating cases extracted from a meticulous time line, based on patents, inventions and publications in newspapers and magazines of the world. The criteria adopted to evaluate the innovation were: characteristics of controls; accessories (mattresses, lighting, siderails, etc.), aesthetic and morphologic properties and outstanding functionalities.

  8. Influence of bed surface changes on snow avalanche simulation

    NASA Astrophysics Data System (ADS)

    Fischer, Jan-Thomas; Issler, Dieter

    2014-05-01

    Gravitational flows, such as snow avalanches, are often modeled employing the shallowness assumption. The driving gravitational force has a first order effect on the dynamics of the flow, especially in complex terrain. Under suitable conditions, erosion and deposition during passage of the flow may change the bed surface by a similar amount as the flow depth itself. The accompanying changes of local slope angle and curvature are particularly significant at the side margins of the flow, where they may induce self-channeling and levée formation. Generally, one ought to expect visible effects wherever the flow depth and velocity are small, e.g., in deposition zones. Most current numerical models in practical use neglect this effect. In order to study the importance of these effects in typical applications, we modified the quasi-3D (depth-averaged) code MoT-Voellmy, which implements the well-known Voellmy friction law that is traditionally used in hazard mapping: The bed shear stress is given by τiz(h,u) = -ui(μgh cosθ+ ku2), ||u|| (1) with μ = O(0.1...0.5) and k = O(10-3...10-2) the dimensionless friction and drag coefficients, respectively. The leading curvature effects, i.e., extra friction due to centrifugal normal forces, are taken into account. The mass and momentum balances are solved by the (simplified) method of transport on a grid whose cells are squares when projected onto the horizontal plane. The direction of depth-averaging is everywhere perpendicular to the topographic surface. A simple erosion model is used. The erosion formula is based on the assumption that the snow cover behaves as a perfectly brittle solid with shear strength τc, above which it instantaneously fails. The erosion rate is derived from the balance of momentum across the interface between bed and flow, where there is a discontinuity of the shear stress, which is given by equation 1 just above the interface and by τc just below it according to the assumptions. This immediately

  9. Thermal effects of a basaltic intrusion on the Soma lignite bed in West Turkey

    SciTech Connect

    Karayigit, A.I.

    1998-01-01

    A mineable lignite bed (k1) in the Soma Formation from the southern part of the Soma basin is of middle Miocene age and was deposited in a lacustrine environment. Its thickness reaches up to 24 m, and it is extensively mined by open-pit methods. The Soma Formation was invaded by an olivine basaltic intrusion during the Pliocene-Pleistocene. The intrusion has resulted in a local contact metamorphic influence at the top level of the k1. The coal bed, on the basis of proximate analyses and random reflectance measurement (%Ro, random) of huminite/vitrinite of coals or groundmass of cokes, can be divided into normal coal, transition zone, and natural coke, differing in their degree of coal metamorphism. Closer to the contact point with the intrusion, moisture and volatile matter contents rapidly decrease, while calorific value and the %Ro, random values increase.

  10. Bed inventory overturn in a circulating fluid bed riser with pant-leg structure

    SciTech Connect

    Jinjing Li; Wei Wang; Hairui Yang; Junfu Lv; Guangxi Yue

    2009-05-15

    The special phenomenon, nominated as bed inventory overturn, in circulating fluid bed (CFB) riser with pant-leg structure was studied with model calculation and experimental work. A compounded pressure drop mathematic model was developed and validated with the experimental data in a cold experimental test rig. The model calculation results agree well with the measured data. In addition, the intensity of bed inventory overturn is directly proportional to the fluidizing velocity and is inversely proportional to the branch point height. The results in the present study provide significant information for the design and operation of a CFB boiler with pant-leg structure. 15 refs., 10 figs., 1 tab.

  11. Hydrogeochemistry and coal-associated bacterial populations from a methanogenic coal bed

    USGS Publications Warehouse

    Barnhart, Elliott P.; Weeks, Edwin P.; Jones, Elizabeth J.P.; Ritter, Daniel J.; McIntosh, Jennifer C.; Clark, Arthur C.; Ruppert, Leslie F.; Cunningham, Alfred B.; Vinson, David S.; Orem, William H.; Fields, Matthew W.

    2016-01-01

    Biogenic coalbed methane (CBM), a microbially-generated source of natural gas trapped within coal beds, is an important energy resource in many countries. Specific bacterial populations and enzymes involved in coal degradation, the potential rate-limiting step of CBM formation, are relatively unknown. The U.S. Geological Survey (USGS) has established a field site, (Birney test site), in an undeveloped area of the Powder River Basin (PRB), with four wells completed in the Flowers-Goodale coal bed, one in the overlying sandstone formation, and four in overlying and underlying coal beds (Knoblach, Nance, and Terret). The nine wells were positioned to characterize the hydraulic conductivity of the Flowers-Goodale coal bed and were selectively cored to investigate the hydrogeochemistry and microbiology associated with CBM production at the Birney test site. Aquifer-test results indicated the Flowers-Goodale coal bed, in a zone from about 112 to 120 m below land surface at the test site, had very low hydraulic conductivity (0.005 m/d) compared to other PRB coal beds examined. Consistent with microbial methanogenesis, groundwater in the coal bed and overlying sandstone contain dissolved methane (46 mg/L average) with low δ13C values (−67‰ average), high alkalinity values (22 meq/kg average), relatively positive δ13C-DIC values (4‰ average), and no detectable higher chain hydrocarbons, NO3−, or SO42−. Bioassay methane production was greatest at the upper interface of the Flowers-Goodale coal bed near the overlying sandstone. Pyrotag analysis identified Aeribacillus as a dominant in situbacterial community member in the coal near the sandstone and statistical analysis indicated Actinobacteria predominated coal core samples compared to claystone or sandstone cores. These bacteria, which previously have been correlated with hydrocarbon-containing environments such as oil reservoirs, have demonstrated the ability to produce biosurfactants to break down

  12. Internal dust recirculation system for a fluidized bed heat exchanger

    DOEpatents

    Gamble, Robert L.; Garcia-Mallol, Juan A.

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  13. Solid fuel feed system for a fluidized bed

    DOEpatents

    Jones, Brian C.

    1982-01-01

    A fluidized bed for the combustion of coal, with limestone, is replenished with crushed coal from a system discharging the coal laterally from a station below the surface level of the bed. A compartment, or feed box, is mounted at one side of the bed and its interior separated from the bed by a weir plate beneath which the coal flows laterally into the bed while bed material is received into the compartment above the plate to maintain a predetermined minimum level of material in the compartment.

  14. 3-D capacitance density imaging of fluidized bed

    DOEpatents

    Fasching, George E.

    1990-01-01

    A three-dimensional capacitance density imaging of a gasified bed or the like in a containment vessel is achieved using a plurality of electrodes provided circumferentially about the bed in levels and along the bed in channels. The electrodes are individually and selectively excited electrically at each level to produce a plurality of current flux field patterns generated in the bed at each level. The current flux field patterns are suitably sensed and a density pattern of the bed at each level determined. By combining the determined density patterns at each level, a three-dimensional density image of the bed is achieved.

  15. Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes

    DOEpatents

    Talmud, Fred M.; Garcia-Mallol, Juan-Antonio

    1980-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

  16. Fast aurora zone analysis

    NASA Technical Reports Server (NTRS)

    Booker, Mattie

    1992-01-01

    The Flight Dynamics Facility (FDF) of the Flight Dynamics Division (FDD), of the Goddard Space Flight Center provides acquisition data to tracking stations and orbit and attitude services to scientists and mission support personnel. The following paper explains how a method was determined that found spacecraft entry and exit times of the aurora zone.

  17. Splenic marginal zone lymphoma.

    PubMed

    Piris, Miguel A; Onaindía, Arantza; Mollejo, Manuela

    Splenic marginal zone lymphoma (SMZL) is an indolent small B-cell lymphoma involving the spleen and bone marrow characterized by a micronodular tumoral infiltration that replaces the preexisting lymphoid follicles and shows marginal zone differentiation as a distinctive finding. SMZL cases are characterized by prominent splenomegaly and bone marrow and peripheral blood infiltration. Cells in peripheral blood show a villous cytology. Bone marrow and peripheral blood characteristic features usually allow a diagnosis of SMZL to be performed. Mutational spectrum of SMZL identifies specific findings, such as 7q loss and NOTCH2 and KLF2 mutations, both genes related with marginal zone differentiation. There is a striking clinical variability in SMZL cases, dependent of the tumoral load and performance status. Specific molecular markers such as 7q loss, p53 loss/mutation, NOTCH2 and KLF2 mutations have been found to be associated with the clinical variability. Distinction from Monoclonal B-cell lymphocytosis with marginal zone phenotype is still an open issue that requires identification of precise and specific thresholds with clinical meaning.

  18. Dilution Zone Mixing

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.

    1983-01-01

    Studies to characterize dilution zone mixing; experiments on the effects of free-stream turbulence on a jet in crossflow; and the development of an interactive computer code for the analysis of the mixing of jets with a confined crossflow are reviewed.

  19. Microgravity Silicon Zoning Investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.

    1985-01-01

    This research program is directed toward the understanding of the float zone crystal growth process, the melt interactions which lead to crystal inhomogeneities, and the influence of microgravity on reducing these inhomogeneities. Silicon was selected as the model crystal because its inhomogeneities lead to known variations in device performance, and because the mechanisms involved in its growth are understood better than for other high temperature crystals. The objective of the program is to understand the growth mechanisms in float zone growth and thereby determine the feasibility and advantages of float zone growth of silicon under microgravity conditions. This will be done by characterizing the growth at g = 1, projecting the changes in melt flows due to microgravity, observing these in space growth and determining the effects on defective inhomogeneities. A Thin Rod Zoner was constructed as a laboratory prototype for flight growth of 5 mm diameter silicon crystals, which can be done within the power and cooling capabilities of shuttle flights. A new method of zoning silicon, using resistance heating, has resulted in melting 5 mm diameter ingots.

  20. Flexible 'zoning' aids adaptability.

    PubMed

    Corben, Simon

    2013-09-01

    Simon Corben, business development director at Capita Symonds' Health team, examines how 'clever use of zoning' when planning new healthcare facilities could improve hospital design, increase inherent flexibility, and reduce lifetime costs, and argues that a 'loose-fit, non-bespoke approach' to space planning will lead to 'more flexible buildings that are suitable for conversion to alternative uses'.

  1. Effects Of Exercise During Prolonged Bed Rest

    NASA Technical Reports Server (NTRS)

    Arnaud, S.; Berry, P; Cohen, M.; Danelis, J.; Deroshia, C.; Greenleaf, J.; Harris, B.; Keil, L.; Bernauer, E.; Bond, M.; Ellis, S.; Lee, P.; Selzer, R.; Wade, C.

    1992-01-01

    Report describes experiment to investigate effects of isotonic and isokinetic leg exercises in counteracting effects of bed rest upon physical and mental conditions of subjects. Data taken on capacity for work, endurance and strength, tolerance to sitting up, equilibrium, posture, gait, atrophy, mineralization and density of bones, endocrine analyses concerning vasoactivity and fluid and electrolyte balances, intermediary metabolism of muscles, mood, and performance.

  2. Fluidized-bed combustion reduces atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Jonke, A. A.

    1972-01-01

    Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

  3. Development and Design of Sludge Freezing Beds

    DTIC Science & Technology

    1988-12-01

    predicting the design depth were developed; values for the input parameters to the models were obtained from the literature or from laboratory and pilot...the freezing and thawing models reveals tit, the design of a freezing bed will depend on the duration and intensity of the freezing and thawing seasons...13 Drying tests ...................................................... 20 Development of design models

  4. Modeling nitrate removal in a denitrification bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Denitrification beds are being promoted to reduce nitrate concentrations in agricultural drainage water to alleviate the adverse environmental effects associated with nitrate pollution in surface water. In this system, water flows through a trench filled with a carbon media where nitrate is transfor...

  5. White Sands, Carrizozo Lava Beds, NM

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground.

  6. 21 CFR 868.5180 - Rocking bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rocking bed. 868.5180 Section 868.5180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES..., thereby using the weight of the abdominal contents to move the diaphragm. (b) Classification. Class...

  7. 21 CFR 880.6070 - Bed board.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bed board. 880.6070 Section 880.6070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices §...

  8. 21 CFR 880.6070 - Bed board.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bed board. 880.6070 Section 880.6070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices §...

  9. Cognitive nonlinear radar test-bed

    NASA Astrophysics Data System (ADS)

    Hedden, Abigail S.; Wikner, David A.; Martone, Anthony; McNamara, David

    2013-05-01

    Providing situational awareness to the warfighter requires radar, communications, and other electronic systems that operate in increasingly cluttered and dynamic electromagnetic environments. There is a growing need for cognitive RF systems that are capable of monitoring, adapting to, and learning from their environments in order to maintain their effectiveness and functionality. Additionally, radar systems are needed that are capable of adapting to an increased number of targets of interest. Cognitive nonlinear radar may offer critical solutions to these growing problems. This work focuses on ongoing efforts at the U.S. Army Research Laboratory (ARL) to develop a cognitive nonlinear radar test-bed. ARL is working toward developing a test-bed that uses spectrum sensing to monitor the RF environment and dynamically change the transmit waveforms to achieve detection of nonlinear targets with high confidence. This work presents the architecture of the test-bed system along with a discussion of its current capabilities and limitations. A brief outlook is presented for the project along with a discussion of a future cognitive nonlinear radar test-bed.

  10. Getting out of Bed: Students' Beliefs

    ERIC Educational Resources Information Center

    Watson, Jane; Callingham, Rosemary

    2015-01-01

    Responses of 223 students in grades 6 to 11 to questions related to beliefs about getting out of bed on the left side are analysed from two perspectives. On one hand the items explore subjective beliefs about chance. On the other hand the different wording and context of the items provide opportunity to show different levels of understanding of…

  11. Exercise Training During Bed Rest Attenuates Deconditioning

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

    1995-01-01

    A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  12. Fluidized bed electrowinning of copper. Final report

    SciTech Connect

    1997-07-01

    The objectives of the study were to: design and construct a 10,000- amp fluidized bed electrowinning cell for the recovery of copper from acidic sulfate solutions; demonstrate the technical feasibility of continuous particle recirculation from the electrowinning cell with the ultimate goal of continuous particle removal; and measure cell efficiency as a function of operating conditions.

  13. Factors affecting gas content in coal beds

    SciTech Connect

    Scott, A.R.; Kaiser, W.R.

    1996-06-01

    Gas content is one of the most important controls on coalbed methane producibility because coal gas production becomes uneconomical if insufficient amounts of gas are sorbed onto the coal surface. Gas content in coal beds is not fixed but changes when equilibrium conditions within the reservoir are disrupted. Therefore, the distribution of gas content varies laterally within individual coal beds, vertically among coals within a single well, and vertically within thicker coal beds. The key hydrogeologic factors affecting gas content variability include gas generation, coal properties, and reservoir conditions. The potential for high gas content depends on thermogenic and secondary biogenic gas generation, which are controlled by burial history (coal rank), maceral composition, and basin hydrodynamics. Coal properties such as ash and moisture content, maceral type, permeability, and diffusion coefficient affect the sorption capacity and diffusion rates in coal beds and, therefore, the final gas content. Reservoir conditions such as pressure and temperature also affect the amount of gases sorbed to the coal surface, whereas coal geometry, hydrogeology, and the presence or absence of permeability barriers determine whether or not gas contents are increased or decreased. Stratigraphic and/or structural trapping concentrates coal gases, resulting in higher gas contents adjacent to permeability barriers; the presence of abnormally high gas contents in lower-rank coals indicates secondary biogenic gas generation and/or conventional trapping of thermogenic or biogenic gases. Gas content decreases in areas of active recharge caused by flushing or in areas of convergent flow where no trapping mechanisms (seals) are present.

  14. Backwater number scaling of alluvial bed forms

    NASA Astrophysics Data System (ADS)

    Shaw, John B.; McElroy, Brandon

    2016-08-01

    The backwater number, Bw, compares the backwater length scale to the length scale of alluvial bed forms. We derive theory to show that Bw plays an important role in determining the behavior and scaling of morphodynamic systems. When Bw ≫ 1, spatial patterns in deposition and erosion derive from flow accelerations associated with changes in flow depth, and bed evolution is akin to a kinematic wave. When Bw ≪ 1, the spatial pattern of shear stress is determined by variations in energy slope, and alluvial beds experience topographic dispersion. This theory is confirmed using a numerical model and data compiled from the literature. We present a data set of Bw for bed forms ranging from dunes to river deltas, including field and experimental measurements. For field-scale measurements, we find that dunes have Bw > 49, braid bars exist in the range Bw = [7.1,17], meanders have a range Bw = [7.1,18], and river mouth deposition ranges over Bw = [7.4,29]. Further, alluvial morphologies that are easily recreated in the laboratory (dunes and avulsions) have overlapping field and laboratory Bw ranges. In contrast, alluvial forms that have traditionally been difficult to recreate (meanders and river mouth processes) have field Bw that are difficult to match in laboratory settings. Large experimental Froude numbers are shown to reduce experimental Bw and incite diffusional behavior. Finally, we demonstrate the utility of Bw scaling for estimating fundamental scales in sedimentary systems.

  15. Hardware survey for the avionics test bed

    NASA Technical Reports Server (NTRS)

    Cobb, J. M.

    1981-01-01

    A survey of maor hardware items that could possibly be used in the development of an avionics test bed for space shuttle attached or autonomous large space structures was conducted in NASA Johnson Space Center building 16. The results of the survey are organized to show the hardware by laboratory usage. Computer systems in each laboratory are described in some detail.

  16. Fluid bed technology in materials processing

    SciTech Connect

    Gupta, C.K.; Sathiyamoorthy, D.

    1999-01-01

    The author explores the various aspects of fluidization engineering and examines its applications in a multitude of materials processing techniques. Topics include process metallurgy, fluidization in nuclear engineering, and the pros and cons of various fluidization equipment. Gupta emphasizes fluidization engineering in high temperature processing, and high temperature fluidized bed furnaces.

  17. Climate conditions in bedded confinement buildings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confinement buildings are utilized for finishing cattle to allow more efficient collection of animal waste and to buffer animals against adverse climatic conditions. Environmental data were obtained from a 29 m wide x 318 m long bedded confinement building with the long axis oriented east to west. T...

  18. River Bed Sediment Classification Using ADCP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Description of physical aquatic habitat in rivers often includes data describing distributions of water depth, velocity and bed material type. Water depth and velocity in streams deeper than about 1 m may be continuously mapped using an acoustic Doppler current profiler from a moving boat. Herein ...

  19. A circulating fluidized-bed furnace for combusting anthracite culm and the thermal-contact pyrolysis of coal

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2007-09-01

    A method for thermal-contact pyrolysis of coal and a furnace design for combusting solid fuel in a circulating fluidized bed are proposed. The geometric, aerodynamic, and physicochemical parameters of the pyrolysis zone situated in the near-wall region of the freeboard space are calculated. It is shown that, if the initial fuel is fed through a part of the annular zone’s cross-sectional area, the near-wall clusters are destroyed and the concentration of the dispersed phase in the reaction zone increases, both resulting in the thermochemical processing of recirculating coke-ash particles to proceed more rapidly.

  20. Pulse Detonation Engine Test Bed Developed

    NASA Technical Reports Server (NTRS)

    Breisacher, Kevin J.

    2002-01-01

    A detonation is a supersonic combustion wave. A Pulse Detonation Engine (PDE) repetitively creates a series of detonation waves to take advantage of rapid burning and high peak pressures to efficiently produce thrust. NASA Glenn Research Center's Combustion Branch has developed a PDE test bed that can reproduce the operating conditions that might be encountered in an actual engine. It allows the rapid and cost-efficient evaluation of the technical issues and technologies associated with these engines. The test bed is modular in design. It consists of various length sections of both 2- and 2.6- in. internal-diameter combustor tubes. These tubes can be bolted together to create a variety of combustor configurations. A series of bosses allow instrumentation to be inserted on the tubes. Dynamic pressure sensors and heat flux gauges have been used to characterize the performance of the test bed. The PDE test bed is designed to utilize an existing calorimeter (for heat load measurement) and windowed (for optical access) combustor sections. It uses hydrogen as the fuel, and oxygen and nitrogen are mixed to simulate air. An electronic controller is used to open the hydrogen and air valves (or a continuous flow of air is used) and to fire the spark at the appropriate times. Scheduled tests on the test bed include an evaluation of the pumping ability of the train of detonation waves for use in an ejector and an evaluation of the pollutants formed in a PDE combustor. Glenn's Combustion Branch uses the National Combustor Code (NCC) to perform numerical analyses of PDE's as well as to evaluate alternative detonative combustion devices. Pulse Detonation Engine testbed.

  1. Updated Performance Evaluation of the ISS Water Processor Multifiltration Beds

    NASA Technical Reports Server (NTRS)

    Bowman, Elizabeth M.; Carter, Layne; Carpenter, Joyce; Orozco, Nicole; Weir, Natalee; Wilson, Mark

    2014-01-01

    The ISS Water Processor Assembly (WPA) produces potable water from a waste stream containing humidity condensate and urine distillate. The primary treatment process is achieved in the Multifiltration Beds, which include adsorbent media and ion exchange resin for the removal of dissolved organic and inorganic contaminants. Two Multifiltration Beds (MF Beds) were replaced on ISS in July 2010 after initial indication of inorganic breakthrough of the first bed and an increasing Total Organic Carbon (TOC) trend in the product water. The first bed was sampled and analyzed Sept 2011 through March 2012. The second MF Bed was sampled and analyzed June 2012 through August 2012. The water resident in the both beds was analyzed for various parameters to evaluate adsorbent loading, performance of the ion exchange resin, microbial activity, and generation of leachates from the ion exchange resin. Portions of the adsorbent media and ion exchange resin were sampled and subsequently desorbed to identify the primary contaminants removed at various points in the bed in addition to microbial analysis. Analysis of the second bed will be compared to results from the first bed to provide a comprehensive overview of how the Multifiltration Beds function on orbit. New data from the second bed supplements the analysis of the first bed (previously reported) and gives a more complete picture of breakthrough compounds, resin breakdown products, microbial activity, and difficult to remove compounds. The results of these investigations and implications to the operation of the WPA on ISS are documented in this paper.

  2. Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Smeenk, J.L.

    1995-04-01

    Experiments performed support the hypothesis that a reducing atmosphere during fluidized bed coal combustion contributes to the formation of agglomerates. Reducing conditions are imposed by controlling the amount of combustion air supplied to the combustor, 50% of theoretical in these experiments. These localized reducing conditions may arise from either poor lateral bed mixing or oxygen-starved conditions due to the coal feed locations. Deviations from steady-state operating conditions in bed pressure drop may be used to detect agglomerate formation. Interpretation of the bed pressure drop was made more straightforward by employing a moving average difference method. During steady-state operation, the difference between the moving point averages should be close to zero, within {plus_minus}0.03 inches of water. Instability within the combustor, experienced once agglomerates begin to form, can be recognized as larger deviations from zero, on the magnitude of {plus_minus}0.15 inches of water.

  3. Centerline Bed Elevation Profile of Sand Bed Channel due to Bar Formation

    NASA Astrophysics Data System (ADS)

    Tholibon, D. A.; Ariffin, J.; Abdullah, J.; Muhamad, N. S.

    2016-07-01

    Numerous data on bar formation have been accumulated yet the methods to predict bar geometry especially bar height are still insufficient. Objectives of this study to determine the trend in term of a significant difference of centreline bed elevation profile along the longitudinal distance. This can be investigate by carried out an experimental work in an erodible sand bed channel using a large-scale physical river model. The study included the various hydraulic characteristics with steady flow rates and sediment supply. An experimental work consists of four matrices of flow rate and channel width with other variables namely grains size and bed slope were kept constant. Analysis have included the discussion on a significant difference of centreline bed elevation profile along the longitudinal distance. As a conclusion the higher velocity in the smaller channel width have induced erosion of the banks that resulted in elevation increase while the larger flow rates have contributed to higher elevation.

  4. 75 FR 24572 - Foreign-Trade Zone 29 - Louisville, Kentucky, Application for Subzone, Louisville Bedding Company...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... and warehouse (26.1 acres) located at 10400 Bunsen Way, Louisville; Site 2 - warehouse (4.3 acres) located at 100 Quality Street, Munfordville; and, Site 3 - manufacturing plant and warehouse (27.7...

  5. Characteristics of Fault Zones in Volcanic Rocks Near Yucca Flat, Nevada Test Site, Nevada

    SciTech Connect

    Donald Sweetkind; Ronald M. Drake II

    2007-11-27

    During 2005 and 2006, the USGS conducted geological studies of fault zones at surface outcrops at the Nevada Test Site. The objectives of these studies were to characterize fault geometry, identify the presence of fault splays, and understand the width and internal architecture of fault zones. Geologic investigations were conducted at surface exposures in upland areas adjacent to Yucca Flat, a basin in the northeastern part of the Nevada Test Site; these data serve as control points for the interpretation of the subsurface data collected at Yucca Flat by other USGS scientists. Fault zones in volcanic rocks near Yucca Flat differ in character and width as a result of differences in the degree of welding and alteration of the protolith, and amount of fault offset. Fault-related damage zones tend to scale with fault offset; damage zones associated with large-offset faults (>100 m) are many tens of meters wide, whereas damage zones associated with smaller-offset faults are generally a only a meter or two wide. Zeolitically-altered tuff develops moderate-sized damage zones whereas vitric nonwelded, bedded and airfall tuff have very minor damage zones, often consisting of the fault zone itself as a deformation band, with minor fault effect to the surrounding rock mass. These differences in fault geometry and fault zone architecture in surface analog sites can serve as a guide toward interpretation of high-resolution subsurface geophysical results from Yucca Flat.

  6. Characteristics of Fault Zones in Volcanic Rocks Near Yucca Flat, Nevada Test Site, Nevada

    USGS Publications Warehouse

    Sweetkind, Donald S.; Drake II, Ronald M.

    2007-01-01

    During 2005 and 2006, the USGS conducted geological studies of fault zones at surface outcrops at the Nevada Test Site. The objectives of these studies were to characterize fault geometry, identify the presence of fault splays, and understand the width and internal architecture of fault zones. Geologic investigations were conducted at surface exposures in upland areas adjacent to Yucca Flat, a basin in the northeastern part of the Nevada Test Site; these data serve as control points for the interpretation of the subsurface data collected at Yucca Flat by other USGS scientists. Fault zones in volcanic rocks near Yucca Flat differ in character and width as a result of differences in the degree of welding and alteration of the protolith, and amount of fault offset. Fault-related damage zones tend to scale with fault offset; damage zones associated with large-offset faults (>100 m) are many tens of meters wide, whereas damage zones associated with smaller-offset faults are generally a only a meter or two wide. Zeolitically-altered tuff develops moderate-sized damage zones whereas vitric nonwelded, bedded and airfall tuff have very minor damage zones, often consisting of the fault zone itself as a deformation band, with minor fault effect to the surrounding rock mass. These differences in fault geometry and fault zone architecture in surface analog sites can serve as a guide toward interpretation of high-resolution subsurface geophysical results from Yucca Flat.

  7. Role of Bed Design and Head-of-Bed Articulation on Patient Migration.

    PubMed

    Davis, Kermit G; Kotowski, Susan E

    2015-01-01

    The ramifications of patient migration toward the foot of the bed in intensive care units are not well understood. Migration may cause shear and friction between the patient and the mattress, reduce elevation of the patient's torso, and require frequent repositioning of the patient. This study assesses how bed design impacts both the amount of migration that patients undergo during head section articulation to 30° and 45° and the extent of torso compression following the articulation.

  8. Role of Bed Design and Head-of-Bed Articulation on Patient Migration

    PubMed Central

    Davis, Kermit G.; Kotowski, Susan E.

    2015-01-01

    The ramifications of patient migration toward the foot of the bed in intensive care units are not well understood. Migration may cause shear and friction between the patient and the mattress, reduce elevation of the patient's torso, and require frequent repositioning of the patient. This study assesses how bed design impacts both the amount of migration that patients undergo during head section articulation to 30° and 45° and the extent of torso compression following the articulation. PMID:25723914

  9. Bed material agglomeration during fluidized bed combustion. Technical progress report, January 1, 1993--March 31, 1993

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.D.

    1993-04-01

    The purpose of this project is to determine the physical and chemical reactions which lead to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. A survey of agglomeration and deposit formation in industrial fluidized bed boilers is in progress. Preliminary results indicate that at least five boilers were experiencing some form of bed material agglomeration. In these instances it was observed that large particles were forming within the bed which were larger that the feed. Four operators could confirm that the larger bed particles had formed due to bed particles sticking together or agglomerating. Deposit formation was reported at nine sites with these deposits being found most commonly at coal feed locations and in cyclones. Other deposit locations included side walls and return loops. Examples of these agglomerates and deposits have been received from five of the surveyed facilities. Also during this quarter, a bulk sample of Illinois No. 6 coal was obtained from the Fossil Energy Program at Ames Laboratory here at Iowa State University and prepared for combustion tests. This sample was first ground to a top-size of 3/8`` using a jaw crusher then a size fraction of 3/8`` {times} 8 (US mesh) was then obtained by sieving using a Gilson Test-Master. This size fraction was selected for the preliminary laboratory-scale experiments designed to simulate the dense bed conditions that exist in the bottom of CFB combustors. To ensure uniformity of fuel composition among combustion runs, the sized coal was riffled using, a cone and long row method and stored in bags for each experiment. During this quarter additional modifications were made to achieve better control of fluidization regimes and to aid in monitoring the hydrodynamic and chemical conditions within the reactor.

  10. Measuring bed shear stress along vegetated river beds using FST-hemispheres.

    PubMed

    Bockelmann-Evans, B N; Davies, R; Falconer, R A

    2008-09-01

    The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28 m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds.

  11. Twin Convergence Zones

    NASA Technical Reports Server (NTRS)

    2002-01-01

    NASA's QuikSCAT satellite has confirmed a 30-year old largely unproven theory that there are two areas near the equator where the winds converge year after year and drive ocean circulation south of the equator. By analyzing winds, QuikSCAT has found a year-round southern and northern Intertropical Convergence Zone. This find is important to climate modelers and weather forecasters because it provides more detail on how the oceans and atmosphere interact near the equator. The Intertropical Convergence Zone (ITCZ) is the region that circles the Earth near the equator, where the trade winds of both the Northern and Southern Hemispheres come together. North of the equator, strong sun and warm water of the equator heats the air in the ITCZ, drawing air in from north and south and causing the air to rise. As the air rises it cools, releasing the accumulated moisture in an almost perpetual series of thunderstorms. Satellite data, however, has confirmed that there is an ITCZ north of the equator and a parallel ITCZ south of the equator. Variation in the location of the ITCZ is important to people around the world because it affects the north-south atmospheric circulation, which redistributes energy. It drastically affects rainfall in many equatorial nations, resulting in the wet and dry seasons of the tropics rather than the cold and warm seasons of higher latitudes. Longer term changes in the ITCZ can result in severe droughts or flooding in nearby areas. 'The double ITCZ is usually only identified in the Pacific and Atlantic Oceans on a limited and seasonal basis,' said Timothy Liu, of NASA's Jet Propulsion Laboratory and California Institute of Technology, Pasadena, Calif., and lead researcher on the project. In the eastern Pacific Ocean, the southern ITCZ is usually seen springtime. In the western Atlantic Ocean, the southern ITCZ was recently clearly identified only in the summertime. However, QuikSCAT's wind data has seen the southern ITCZ in all seasons across the

  12. Some Bed Bugs Can Traipse Out of Traps

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_164107.html Some Bed Bugs Can Traipse Out of Traps Researchers find one ... News) -- They may need to build a better bed bug trap. That might be the point of a ...

  13. A low tritium hydride bed inventory estimation technique

    SciTech Connect

    Klein, J.E.; Shanahan, K.L.; Baker, R.A.; Foster, P.J.

    2015-03-15

    Low tritium hydride beds were developed and deployed into tritium service in Savannah River Site. Process beds to be used for low concentration tritium gas were not fitted with instrumentation to perform the steady-state, flowing gas calorimetric inventory measurement method. Low tritium beds contain less than the detection limit of the IBA (In-Bed Accountability) technique used for tritium inventory. This paper describes two techniques for estimating tritium content and uncertainty for low tritium content beds to be used in the facility's physical inventory (PI). PI are performed periodically to assess the quantity of nuclear material used in a facility. The first approach (Mid-point approximation method - MPA) assumes the bed is half-full and uses a gas composition measurement to estimate the tritium inventory and uncertainty. The second approach utilizes the bed's hydride material pressure-composition-temperature (PCT) properties and a gas composition measurement to reduce the uncertainty in the calculated bed inventory.

  14. Bed bugs (Cimex lectularius) as vectors of Trypanosoma cruzi.

    PubMed

    Salazar, Renzo; Castillo-Neyra, Ricardo; Tustin, Aaron W; Borrini-Mayorí, Katty; Náquira, César; Levy, Michael Z

    2015-02-01

    Populations of the common bed bug, Cimex lectularius, have recently undergone explosive growth. Bed bugs share many important traits with triatomine insects, but it remains unclear whether these similarities include the ability to transmit Trypanosoma cruzi, the etiologic agent of Chagas disease. Here, we show efficient and bidirectional transmission of T. cruzi between hosts and bed bugs in a laboratory environment. Most bed bugs that fed on experimentally infected mice acquired the parasite. A majority of previously uninfected mice became infected after a period of cohabitation with exposed bed bugs. T. cruzi was also transmitted to mice after the feces of infected bed bugs were applied directly to broken host skin. Quantitative bed bug defecation measures were similar to those of important triatomine vectors. Our findings suggest that the common bed bug may be a competent vector of T. cruzi and could pose a risk for vector-borne transmission of Chagas disease.

  15. Bed Bugs (Cimex lectularius) as Vectors of Trypanosoma cruzi

    PubMed Central

    Salazar, Renzo; Castillo-Neyra, Ricardo; Tustin, Aaron W.; Borrini-Mayorí, Katty; Náquira, César; Levy, Michael Z.

    2015-01-01

    Populations of the common bed bug, Cimex lectularius, have recently undergone explosive growth. Bed bugs share many important traits with triatomine insects, but it remains unclear whether these similarities include the ability to transmit Trypanosoma cruzi, the etiologic agent of Chagas disease. Here, we show efficient and bidirectional transmission of T. cruzi between hosts and bed bugs in a laboratory environment. Most bed bugs that fed on experimentally infected mice acquired the parasite. A majority of previously uninfected mice became infected after a period of cohabitation with exposed bed bugs. T. cruzi was also transmitted to mice after the feces of infected bed bugs were applied directly to broken host skin. Quantitative bed bug defecation measures were similar to those of important triatomine vectors. Our findings suggest that the common bed bug may be a competent vector of T. cruzi and could pose a risk for vector-borne transmission of Chagas disease. PMID:25404068

  16. Mapping seagrass beds and coral reefs in the coastal region of Vietnam using VNREDSAT-1 data

    NASA Astrophysics Data System (ADS)

    Lau, K. V.; Chen, C. F.; Nguyen, S. T.; Chen, C. R.; Tong Phuoc, H. S.; Nguyen, H. H.

    2015-12-01

    Seagrass beds and coral reefs are two important ecosystems in the coastal zone. They play an important role to protect and shelter various marine organisms. Both seagrass beds and coral reefs could prevent the coastline from erosion. While seagrass stabilizes sediments and acts as a biofilter, coral reefs can control carbon dioxide in the ocean water. Besides, seagrass also provides direct food for many fish and marine animals. Therefore, mapping seagrass beds and coral reefs is very important for coastal management and conservation. In May 2013, Vietnam launched the first satellite for earth observations, called Vietnam Natural Resources, Environment and Disaster Monitoring Satellite (VNREDSAT-1). It is a great opportunity for environmental monitoring in the country using the data from this satellite. The objective of this study is to use the VNREDSAT-1 data to map seagrass beds and coral reefs in the coastal region of Ninh Hai district, Ninh Thuan province, Vietnam, where the seagrass still remains in good a condition. We processed the VNREDSAT-1 image through four steps: (1) Atmospheric correction using Second Simulation of the Satellite Signal in the Solar Spectrum radiative transfer model (6S), (2) Sun glint removal by using Hedley method, (3) Water column correction using the depth-variant index (DII) proposed by Lyzenga, and (4) Image classification using the maximum likelihood algorithm. The mapping results verified with the ground reference data showed a good overall accuracy of 75% and Kappa coefficient of 0.7. The total area of seagrass beds was approximately 323.09 ha, which mainly distributed in My Hoa and Thai An villages. The total area of coral reefs was approximately 564.42 ha, located along the coast and on outer area to seagrass and shoreline reefs. This study demonstrates the applicability of VNREDSAT-1 for underwater habitat monitoring. The results could be useful for natural resources managers to devise strategies for management and

  17. The CFB boiler in Gardanne -- An experimental investigation of its bottom zone

    SciTech Connect

    Wiesendorf, V.; Hartge, E.U.; Werther, J.; Johnsson, F.; Sterneus, J.; Leckner, B.; Montat, D.; Briand, P.

    1999-07-01

    Different measurement techniques have been used to analyze the fluid dynamics in the bottom zone of the 250 MW{sub e} Circulating Fluidized Bed (CFB) boiler in Gardanne, France. In particular, horizontal profiles of the local solids volume concentration have been measured with a capacitance probe and the vertical pressure profile has been measured by a probe with densely spaced pressure taps. Local velocities were measured by cross-correlating the signals of a two-channel capacitance probe. In order to get some information on the influence of the flow structure on local combustion conditions a probe has been used which combines both capacitance and zirconia-cell sensors. This probe measured simultaneously local solids volume concentrations, local velocities and the local presence of oxygen. The results show the existence of a dense bed with a bed height of about 2% of the total riser height. This bottom bed has a flow structure which is different from the core-annulus structure observed in the upper dilute zone of the CFB combustor by several researchers. The lateral solids mixing does not seem to be enough to provide an even distribution of char over the whole cross-section of the bottom bed. Nevertheless, an even temperature distribution has been found indicating that mixing is sufficient to equalize the uneven heat generation.

  18. Method of feeding particulate material to a fluidized bed

    DOEpatents

    Borio, Richard W.; Goodstine, Stephen L.

    1984-01-01

    A centrifugal spreader type feeder that supplies a mixture of particulate limestone and coal to the top of a fluidized bed reactor having a flow of air upward therethrough. Large particles of particulate matter are distributed over the upper surface of the bed to utilize the natural mixing within the bed, while fine particles are adapted to utilize an independent feeder that separates them from the large particles and injects them into the bed.

  19. Vadose zone water fluxmeter

    DOEpatents

    Faybishenko, Boris A.

    2005-10-25

    A Vadose Zone Water Fluxmeter (WFM) or Direct Measurement WFM provides direct measurement of unsaturated water flow in the vadose zone. The fluxmeter is a cylindrical device that fits in a borehole or can be installed near the surface, or in pits, or in pile structures. The fluxmeter is primarily a combination of tensiometers and a porous element or plate in a water cell that is used for water injection or extraction under field conditions. The same water pressure measured outside and inside of the soil sheltered by the lower cylinder of the fluxmeter indicates that the water flux through the lower cylinder is similar to the water flux in the surrounding soil. The fluxmeter provides direct measurement of the water flow rate in the unsaturated soils and then determines the water flux, i.e. the water flow rate per unit area.

  20. Fluidized Bed Asbestos Sampler Design and Testing

    SciTech Connect

    Karen E. Wright; Barry H. O'Brien

    2007-12-01

    A large number of samples are required to characterize a site contaminated with asbestos from previous mine or other industrial operations. Current methods, such as EPA Region 10’s glovebox method, or the Berman Elutriator method are time consuming and costly primarily because the equipment is difficult to decontaminate between samples. EPA desires a shorter and less costly method for characterizing soil samples for asbestos. The objective of this was to design and test a qualitative asbestos sampler that operates as a fluidized bed. The proposed sampler employs a conical spouted bed to vigorously mix the soil and separate fine particulate including asbestos fibers on filters. The filters are then analyzed using transmission electron microscopy for presence of asbestos. During initial testing of a glass prototype using ASTM 20/30 sand and clay fines as asbestos surrogates, fine particulate adhered to the sides of the glass vessel and the tubing to the collection filter – presumably due to static charge on the fine particulate. This limited the fines recovery to ~5% of the amount added to the sand surrogate. A second prototype was constructed of stainless steel, which improved fines recovery to about 10%. Fines recovery was increased to 15% by either humidifying the inlet air or introducing a voltage probe in the air space above the sample. Since this was not a substantial improvement, testing using the steel prototype proceeded without using these techniques. Final testing of the second prototype using asbestos suggests that the fluidized bed is considerably more sensitive than the Berman elutriator method. Using a sand/tremolite mixture with 0.005% tremolite, the Berman elutriator did not segregate any asbestos structures while the fluidized bed segregated an average of 11.7. The fluidized bed was also able to segregate structures in samples containing asbestos at a 0.0001% concentration, while the Berman elutriator method did not detect any fibers at this

  1. Radiant zone heated particulate filter

    DOEpatents

    Gonze, Eugene V [Pinckney, MI

    2011-12-27

    A system includes a particulate matter (PM) filter including an upstream end for receiving exhaust gas and a downstream end. A radiant zoned heater includes N zones, where N is an integer greater than one, wherein each of the N zones includes M sub-zones, where M is an integer greater than or equal to one. A control module selectively activates at least a selected one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones, restricts exhaust gas flow in a portion of the PM filter that corresponds to the selected one of the N zones, and deactivates non-selected ones of the N zones.

  2. Renewable liquid reflecting zone plate

    DOEpatents

    Toor, Arthur; Ryutov, Dmitri D.

    2003-12-09

    A renewable liquid reflecting zone plate. Electrodes are operatively connected to a dielectric liquid in a circular or other arrangement to produce a reflecting zone plate. A system for renewing the liquid uses a penetrable substrate.

  3. Trojans in habitable zones.

    PubMed

    Schwarz, Richard; Pilat-Lohinger, Elke; Dvorak, Rudolf; Erdi, Balint; Sándor, Zsolt

    2005-10-01

    With the aid of numerical experiments we examined the dynamical stability of fictitious terrestrial planets in 1:1 mean motion resonance with Jovian-like planets of extrasolar planetary systems. In our stability study of the so-called "Trojan" planets in the habitable zone, we used the restricted three-body problem with different mass ratios of the primary bodies. The application of the three-body problem showed that even massive Trojan planets can be stable in the 1:1 mean motion resonance. From the 117 extrasolar planetary systems only 11 systems were found with one giant planet in the habitable zone. Out of this sample set we chose four planetary systems--HD17051, HD27442, HD28185, and HD108874--for further investigation. To study the orbital behavior of the stable zone in the different systems, we used direct numerical computations (Lie Integration Method) that allowed us to determine the escape times and the maximum eccentricity of the fictitious "Trojan planets."

  4. Petrology and Bulk Chemistry of Modern Bed Load Sediments From Rivers Draining the Eastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Borges, J. B.

    2003-12-01

    We studied river bed load petrology and bulk sediment chemistry of the headwaters of the Changjiang, Huang He and Red rivers in China and Vietnam. These rivers drain the eastern and southeastern parts of the Tibetan Plateau which includes part of the Indian-Eurasian suture zone. The eastern Tibetan Plateau is dominated by marine sedimentary rocks with a few scattered intrusive igneous outcrops, while the suture zone is characterized by a mixture of high-grade metamorphic, ultramafic, granitic, volcanic arc and marine sedimentary rocks. The arithmetic average for Qt: Ft: Rft along the suture zone varies from 56:2:42 along the Red River Fault (RRF) zone to 38:6:56 in the interior of the continent, while sands from rivers draining the plateau average 32:8:60. The sands analyzed in this study are relatively immature compared to most data available from most rivers in the tropics. The average Chemical Index of Alteration (CIA) for samples from the RRF suture zone (0.62) is similar to that of rivers draining other tropical regions like the Niger, Chao Phraya, Mekong, Ganges, Amazon and Brahmaputra. The CIA values from the RRF zone are also significantly different from the rest of the suture zone (0.36) and the plateau area (0.38). The difference can be attributed to the combined effect of relief and precipitation. The RRF lies in the Red River drainage and receives ˜1820 mm of precipitation annually, while the plateau area averages ˜620 mm annually. In the case of the Red River drainage, the relief combined with higher humidity can increase physical weathering and reduce the residence time of sediment in the river drainage, therefore, continuously replacing the sediment transported out of the drainage by freshly weathered immature materials. In the plateau area, lower precipitation and runoff may limit sediment transport and chemical weathering leading to sediment immaturity.

  5. 21 CFR 880.2400 - Bed-patient monitor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bed-patient monitor. 880.2400 Section 880.2400... Devices § 880.2400 Bed-patient monitor. (a) Identification. A bed-patient monitor is a battery-powered device placed under a mattress and used to indicate by an alarm or other signal when a patient...

  6. Heat exchanger support apparatus in a fluidized bed

    DOEpatents

    Lawton, Carl W.

    1982-01-01

    A heat exchanger is mounted in the upper portion of a fluidized combusting bed for the control of the temperature of the bed. A support, made up of tubes, is extended from the perforated plate of the fluidized bed up to the heat exchanger. The tubular support framework for the heat exchanger has liquid circulated therethrough to prevent deterioration of the support.

  7. 21 CFR 880.6060 - Medical disposable bedding.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical disposable bedding. 880.6060 Section 880...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices § 880.6060 Medical disposable bedding. (a) Identification. Medical disposable bedding is a...

  8. 21 CFR 880.6060 - Medical disposable bedding.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical disposable bedding. 880.6060 Section 880...) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Miscellaneous Devices § 880.6060 Medical disposable bedding. (a) Identification. Medical disposable bedding is a...

  9. Dual fluidized bed design for the fast pyrolysis of biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mechanism for the transport of solids between fluidised beds in dual fluidised bed systems for the fast pyrolysis of biomass process was selected. This mechanism makes use of an overflow standpipe to transport solids from the fluidised bed used for the combustion reactions to a second fluidised be...

  10. Johnson Space Center's Regenerative Life Support Systems Test Bed.

    PubMed

    Barta, D J; Henninger, D L

    1996-01-01

    The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

  11. Radioactivity in fossils at the Hagerman Fossil Beds National Monument.

    PubMed

    Farmer, C Neal; Kathren, Ronald L; Christensen, Craig

    2008-08-01

    Since 1996, higher than background levels of naturally occurring radioactivity have been documented in both fossil and mineral deposits at Hagerman Fossil Beds National Monument in south-central Idaho. Radioactive fossil sites occur primarily within an elevation zone of 900-1000 m above sea level and are most commonly found associated with ancient river channels filled with sand. Fossils found in clay rich deposits do not exhibit discernable levels of radioactivity. Out of 300 randomly selected fossils, approximately three-fourths exhibit detectable levels of natural radioactivity ranging from 1 to 2 orders of magnitude above ambient background levels when surveyed with a portable hand held Geiger-Muller survey instrument. Mineral deposits in geologic strata also show above ambient background levels of radioactivity. Radiochemical lab analysis has documented the presence of numerous natural radioactive isotopes. It is postulated that ancient groundwater transported radioactive elements through sand bodies containing fossils which precipitated out of solution during the fossilization process. The elevated levels of natural radioactivity in fossils may require special precautions to ensure that exposures to personnel from stored or displayed items are kept as low as reasonably achievable (ALARA).

  12. Predicting bed form roughness: the influence of lee side angle

    NASA Astrophysics Data System (ADS)

    Lefebvre, Alice; Winter, Christian

    2016-04-01

    Flow transverse bedforms (ripples and dunes) are ubiquitous in rivers and coastal seas. Local hydrodynamics and transport conditions depend on the size and geometry of these bedforms, as they constitute roughness elements at the bed. Bedform influence on flow energy must be considered for the understanding of flow dynamics, and in the development and application of numerical models. Common estimations or predictors of form roughness (friction factors) are based mostly on data of steep bedforms (with angle-of-repose lee slopes), and described by highly simplified bedform dimensions (heights and lengths). However, natural bedforms often are not steep, and differ in form and hydraulic effect relative to idealised bedforms. Based on systematic numerical model experiments, this study shows how the hydraulic effect of bedforms depends on the flow structure behind bedforms, which is determined by the bedform lee side angle, aspect ratio and relative height. Simulations reveal that flow separation behind bedform crests and, thus, a hydraulic effect is induced at lee side angles steeper than 11 to 18° depending on relative height, and that a fully developed flow separation zone exists only over bedforms with a lee side angle steeper than 24°. Furthermore, the hydraulic effect of bedforms with varying lee side angle is evaluated and a reduction function to common friction factors is proposed. A function is also developed for the Nikuradse roughness (k s), and a new equation is proposed which directly relates k s to bedform relative height, aspect ratio and lee side angle.

  13. Deep Bed Adsorption Testing using Silver-Functionalized Aerogel

    SciTech Connect

    Nick Soelberg; Tony Watson

    2012-06-01

    Nuclear fission results in the production of fission products and activation products, some of which tend to be volatile during used fuel reprocessing and evolve in gaseous species into the reprocessing facility off-gas systems. Analyses have shown that I129, due to its radioactivity, high potential mobility in the environment, and high longevity (half life of 15.7 million years), can require control efficiencies of up to 1,000x or higher to meet regulatory emission limits. Two Aerogel sorption tests that have been performed this fiscal year. The maximum iodine decontamination factor (DF) was measured to be over 10,000, above the 1,000-10,000 target DF range. The mass transfer zone may be as short as 0.5 inches under the sorption conditions of the first test. Only a small fraction of the iodine sorbed on Bed 1 was desorbed during the purge periods. The silver-functionalized Aerogel appears to have potential to be a very effective and efficient iodine sorbent.

  14. Johnson Space Center's Regenerative Life Support Systems Test Bed

    NASA Technical Reports Server (NTRS)

    Barta, D. J.; Henninger, D. L.

    1996-01-01

    The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

  15. Johnson Space Center's regenerative life support systems test bed

    NASA Technical Reports Server (NTRS)

    Henninger, Donald L.; Tri, Terry O.; Barta, Daniel J.; Stahl, Randal S.

    1991-01-01

    The Regenerative Life Support System (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for the evaluation of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. When completed, the facility will be comprised of two large scale plant growth chambers, each with approximately 10 m(exp 2) growing area. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), will be capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in Lunar or Martian habitats; the other chamber, the Ambient Pressure Growth Chamber (APGC) will operate at ambient atmospheric pressure. The root zone in each chamber will be configurable for hydroponic or solid state media systems. Research will focus on: (1) in situ resource utilization for CELSS systems, in which simulated lunar soils will be used in selected crop growth studies; (2) integration of biological and physicochemical air and water revitalization systems; (3) effect of atmospheric pressure on system performance; and (4) monitoring and control strategies.

  16. Continuous desorption rate measurement from a shallow-bed of poly(styrene-divinylbenzene) particles with correction for experimental artifacts.

    PubMed

    Bujalski, Robert; Cantwell, Frederick F

    2004-09-10

    A 0.50 mm high bed, containing ca. 3 mg of the nominally non-porous poly(styrene-divinylbenzene) (PS-DVB) sorbent Hamilton PRP-infinity, is located in a valve. After the bed is pre-equilibrated with a (7/3) methanol/water solution of naphthalene (NA), the valve is switched and (7/3) methanol/water solvent flows continuously through the bed at a high linear velocity. This causes NA to desorb into a constantly refreshed solvent, creating a "shallow-bed" contactor with an "infinite bath" kinetic condition. The effluent from the bed passes through a UV-absorbance detector which generates the observed instantaneous desorption rate curve for NA. The same experiment is performed using the solute phloroglucinol (PG), which is not sorbed by PRP-infinity and serves as an "impulse response function marker" (IRF-Marker). The resulting peak-shaped IRF curve is used in two ways (i.e. subtraction and deconvolution) in order to correct the observed instantaneous rate curve of NA for the following experimental artifacts: hold-up volume of the bed and valve, transit-delay time between the bed and the detector and instrument bandbroadening of the NA zone. The cumulative desorption rate curve, which is a plot of moles NA desorbed versus time, is obtained by integration. It is found to be accurately described by the theoretical equation for homogeneous spherical diffusion. The diffusion coefficient of NA inside the PRP-infinity particles (5.0+/-0.6) x 10(-11) cm2/s, agrees with the literature value that was obtained from the sorption rate of NA into the same particles. This constitutes virtually conclusive evidence for diffusion control of intra-particle kinetics of NA in the PS-DVB matrix of PRP-infinity and related polymers. The influence of both sorbent and solute properties on the method is evaluated.

  17. Internal Combustion Engines as Fluidized Bed Reactors

    NASA Astrophysics Data System (ADS)

    Lavich, Zoe; Taie, Zachary; Menon, Shyam; Beckwith, Walter; Daly, Shane; Halliday, Devin; Hagen, Christopher

    2016-11-01

    Using an internal combustion engine as a chemical reactor could provide high throughput, high chemical conversion efficiency, and reactant/product handling benefits. For processes requiring a solid catalyst, the ability to develop a fluidized bed within the engine cylinder would allow efficient processing of large volumes of fluid. This work examines the fluidization behavior of particles in a cylinder of an internal combustion engine at various engine speeds. For 40 micron silica gel particles in a modified Megatech Mark III transparent combustion engine, calculations indicate that a maximum engine speed of about 60.8 RPM would result in fluidization. At higher speeds, the fluidization behavior is expected to deteriorate. Experiments gave qualitative confirmation of the analytical predictions, as a speed of 48 RPM resulted in fluidized behavior, while a speed of 171 RPM did not. The investigation shows that under certain conditions a fluidized bed can be obtained within an engine cylinder. Corresponding Author.

  18. Capillary movement of liquid in granular beds

    SciTech Connect

    Yendler, B.; Webbon, B.

    1993-12-31

    Knowledge of capillary migration of liquids in granular beds in microgravity is essential for the development of a substrate based nutrient delivery sytem for the growth of plants in space. This problem is also interesting from the theoretical as well as the practical point of view. The purpose of this study was to model capillary water propagation through a granular bed in microgravity. In our ground experiments, water propagation is driven primarily by capillary force. Data for spherical partical sizes in the range from 0.46 to 2 mm have been obtained. It was shown that the velocity of water propagation is very sensitive to particle size. Theoretical consideration is also provided. Actual space flight experiments are planned for the future to confirm our results.

  19. Fluidized bed boiler having a segmented grate

    DOEpatents

    Waryasz, Richard E.

    1984-01-01

    A fluidized bed furnace (10) is provided having a perforate grate (9) within a housing which supports a bed of particulate material including some combustibles. The grate is divided into a plurality of segments (E2-E6, SH1-SH5, RH1-RH5), with the airflow to each segment being independently controlled. Some of the segments have evaporating surface imbedded in the particulate material above them, while other segments are below superheater surface or reheater surface. Some of the segments (E1, E7) have no surface above them, and there are ignitor combustors (32, 34) directed to fire into the segments, for fast startup of the furnace without causing damage to any heating surface.

  20. Insecticide-resistance in bed-bugs

    PubMed Central

    Busvine, James R.

    1958-01-01

    A simple method of measuring insecticide-resistance in bed-bugs is described. Batches of adult bugs are put on small pieces of filter-paper impregnated with oil solutions of insecticides, and mortality is estimated after 5 days at 25°C. In both Cimex lectularius and C. hemipterus, two kinds of resistance can develop, either independently or in conjunction. One involves DDT, methoxychlor and analogues; it cannot be overcome by the addition of DMC. The other involves γ-BHC, dieldrin and various other chlorinated cyclodiene insecticides. The resistance spectrum of bed-bugs towards this group of compounds resembles those of Anopheles gambiae and Musca domestica, indicating similarity in the defence mechanism. PMID:20604028

  1. Vadose Zone Transport Field Study: Summary Report

    SciTech Connect

    Ward, Andy L.; Conrad, Mark E.; Daily, William D.; Fink, James B.; Freedman, Vicky L.; Gee, Glendon W.; Hoversten, Gary M.; Keller, Jason M.; Majer, Ernest L.; Murray, Christopher J.; White, Mark D.; Yabusaki, Steven B.; Zhang, Z. F.

    2006-07-31

    migration (e.g. BC Cribs and Trenches). The improved models have been also coupled with inverse models and newly-developed parameter scaling techniques to allow estimation of field-scale and effective transport parameters for the vadose zone. The development and utility of pedotransfer functions for describing fine-scale hydrogeochemical heterogeneity and for incorporating this heterogeneity into reactive transport models was explored. An approach based on grain-size statistics appears feasible and has been used to describe heterogeneity in hydraulic properties and sorption properties, such as the cation exchange capacity and the specific surface area of Hanford sediments. This work has also led to the development of inverse modeling capabilities for time-dependent, subsurface, reactive transport with transient flow fields using an automated optimization algorithm. In addition, a number of geophysical techniques investigated for their potential to provide detailed information on the subtle changes in lithology and bedding surfaces; plume delineation, leak detection. High-resolution resistivity is now being used for detecting saline plumes at several waste sites at Hanford, including tank farms. Results from the field studies and associated analysis have appeared in more than 46 publications generated over the past 4 years. These publications include test plans and status reports, in addition to numerous technical notes and peer reviewed papers.

  2. Numerical and experimental studies on thermal deformation of ceramic breeder pebble bed systems

    NASA Astrophysics Data System (ADS)

    An, Zhiyong

    The goal of this work is to develop modeling capabilities for understanding and predicting thermo-mechanical behavior of ceramic breeder pebble bed systems at elevated temperatures (600-800°C). The thermo-mechanical behavior of solid breeder pebble beds is a critical issue for the solid breeder blanket designs and is different from the behaviors of solid materials. The issue includes potential breakage of pebble materials and change in heat transfer characteristics across the breeder materials and cladding interface. Furthermore, at elevated temperatures, thermal creep deformation plays an uncertain role related to the contact stresses in the pebble beds. To understand these effects, the following efforts have been undertaken: First, experiments of a typical breeder blanket design have been conducted to study the thermal creep behaviors of the pebble bed system. Other than providing data for benchmarking numerical simulation, the experimental results show that the thermal deformation behaviors of typical pebble materials, such as Li2O and Li4SiO4 lithium ceramics, are nonlinear with respect to time and temperature. Under fixed temperatures (higher than 600°C), stresses generated from differential thermal expansion begin to decrease as a result of creep deformation. Second, a new numerical program, based on discrete element method (DEM), has been developed to simulate the fundamental mechanical behaviors of the packed pebble bed system. Considering the effects in a high temperature situation, inelastic contact models have been derived to predict thermal creep deformation. Our DEM program is mainly used to derive the effective mechanical constitutive equations for a pebble bed system. Besides that, it can provide the stress distribution inside the pebble bed and the force evolution related to the changes of boundary loadings. Last, a numerical program based on the finite element analysis (FEA) has been utilized to simulate the stress magnitude and deformation

  3. A new bed elevation dataset for Greenland

    NASA Astrophysics Data System (ADS)

    Griggs, J. A.; Bamber, J. L.; Hurkmans, R. T. W. L.; Dowdesewell, J. A.; Gogineni, S. P.; Howat, I.; Mouginot, J.; Paden, J.; Palmer, S.; Rignot, E.; Steinhage, D.

    2012-11-01

    We present a new bed elevation dataset for Greenland derived from a combination of multiple airborne ice thickness surveys undertaken between the 1970s and 2011. Around 344 000 line kilometres of airborne data were used, with the majority of this having been collected since the year 2000, when the last comprehensive compilation was undertaken. The airborne data were combined with satellite-derived elevations for non glaciated terrain to produce a consistent bed digital elevation model (DEM) over the entire island including across the glaciated/ice free boundary. The DEM was extended to the continental margin with the aid of bathymetric data, primarily from a compilation for the Arctic. Ice shelf thickness was determined where a floating tongue exists, in particular in the north. The across-track spacing between flight lines warranted interpolation at 1 km postings near the ice sheet margin and 2.5 km in the interior. Grids of ice surface elevation, error estimates for the DEM, ice thickness and data sampling density were also produced alongside a mask of land/ocean/grounded ice/floating ice. Errors in bed elevation range from a minimum of ±6 m to about ±200 m, as a function of distance from an observation and local topographic variability. A comparison with the compilation published in 2001 highlights the improvement in resolution afforded by the new data sets, particularly along the ice sheet margin, where ice velocity is highest and changes most marked. We use the new bed and surface DEMs to calculate the hydraulic potential for subglacial flow and present the large scale pattern of water routing. We estimate that the volume of ice included in our land/ice mask would raise eustatic sea level by 7.36 m, excluding any solid earth effects that would take place during ice sheet decay.

  4. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    SciTech Connect

    Not Available

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  5. Predicting apparent Sherwood numbers for fluidized beds

    SciTech Connect

    Groenewold, H.; Tsotsas, E.

    1999-09-01

    Mass transfer data of bubbling fluidized beds have been reevaluated with a new model which is completely predictive. The model is based on a two-phase approach with active bypass, formally plug flow for the suspension gas and a consideration of backmixing in the main kinetic coefficient, i.e. in the apparent particle-to-fluid Sherwood number. A good agreement with experimental results of various authors with a broad range of Reynolds numbers and particle diameters is demonstrated.

  6. Development and Design of Sludge Freezing Beds

    DTIC Science & Technology

    1988-12-01

    Mathematical models for predicting the design depth were developed; values for the input parameters to the models were obtained from the literature or...those of ice. An analysis of the freezing and thawing models rqvvals that the design of a freezing bed will depend on the duration and intensity of the...also conducted with these sludges in the unfrozen state. Mathematical models were developed to predict the design depth based on the natural freezing

  7. Clinical use of the hyperbaric oxygen bed

    PubMed Central

    Ashfield, R.; Drew, C. E.

    1969-01-01

    The Vickers hyperbaric oxygen bed is described and details of its use are given in the treatment of 207 patients with a wide variety of clinical conditions. As part of a deliberate policy, a special study was made of its place in the treatment of severe acute myocardial infarction. No major procedural difficulties were encountered. Results are generally encouraging and frequently of dramatic benefit. ImagesFig. 1 PMID:5358379

  8. Particle Dynamics and Gravel-Bed Adjustments

    DTIC Science & Technology

    1993-05-01

    detecteur des movement des sediments fins. Societe hydrotechnique de France. Transport Hydraulique et Decantation des Materiaux Solides. pp3 9 p. 38...Kirkby, MJ. (Eds.) Channel Ndork Hydrology. Wiley. Chichester. pp 129-173. 67. Lapointe, M.F. (1992) Burst-like sediment suspension events in a sand bed...alluvial sand suspension by eddy correlation. Earth Surface Processes & Landforms, 11, (in press). 69. Soulsby, R.L. (1983) The bottom boundary layer of

  9. Anthracite culm fired fluidized-bed boiler

    SciTech Connect

    Lentz, E.C.

    1984-01-01

    The author describes a fluidised-bed boiler that has been designed by FluiDyne Engineering Corp. for the combustion of anthracite culm, a material containing about 40% ash and consisting of coal particles embedded in mineral matter. There are some 900 million tons of anthracite culm in northeast Pennsylvania within easy reach of many large metropolitan areas. It is estimated that the material can be used economically within a distance of 200 miles.

  10. Telerobotics test bed for space structure assembly

    NASA Technical Reports Server (NTRS)

    Kitami, M.; Ogimoto, K.; Yasumoto, F.; Katsuragawa, T.; Itoko, T.; Kurosaki, Y.; Hirai, S.; Machida, K.

    1994-01-01

    A cooperative research on super long distance space telerobotics is now in progress both in Japan and USA. In this program. several key features will be tested, which can be applicable to the control of space robots as well as to terrestrial robots. Local (control) and remote (work) sites will be shared between Electrotechnical Lab (ETL) of MITI in Japan and Jet Propulsion Lab (JPL) in USA. The details of a test bed for this international program are discussed in this report.

  11. Modeling RDX Reduction within Iron Bed Reactors

    DTIC Science & Technology

    2013-09-01

    completely flushed. The third test case for the hypothetical batch reactor was conducted with a constant RDX loading as prescribed for a water...of RDX. Likewise, constant concentrations of RDX degradation products are produced. The results for all three of the hypothetical batch reactor ...a model to predict the degradation of RDX and its degradation products within an iron bed reactor . A batch reactor model and a one- dimensional (1D

  12. SSME technology test bed fast shutdown assessment

    NASA Technical Reports Server (NTRS)

    Liebman, A.; Vilja, J. O.

    1988-01-01

    The fastest practical shutdown sequence for the Technology Test Bed Engine is developed. A sequence is defined and key issues addressed. The conclusion of the study is that a fastest shutdown sequence within the existing SSME design capability is practical and can cut oxidizer consumption by 50 percent. However, the revised sequence would not have prevented any of the prior experienced SSME incidents and would introduce development risk to the program.

  13. Pulsed atmospheric fluidized bed combustion. Final report

    SciTech Connect

    1998-03-01

    ThermoChem, under contract to the Department of Energy, conducted extensive research, development and demonstration work on a Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) to confirm that advanced technology can meet these performance objectives. The ThermoChem/MTCI PAFBC system integrates a pulse combustor with an atmospheric bubbling-bed type fluidized bed combustor (BFBC) In this modular configuration, the pulse combustor burns the fuel fines (typically less than 30 sieve or 600 microns) and the fluidized bed combusts the coarse fuel particles. Since the ThermoChem/MTCI PAFBC employs both the pulse combustor and the AFBC technologies, it can handle the full-size range of coarse and fines. The oscillating flow field in the pulse combustor provides for high interphase and intraparticle mass transfer rates. Therefore, the fuel fines essentially burn under kinetic control. Due to the reasonably high temperature (>1093 C but less than the temperature for ash fusion to prevent slagging), combustion of fuel fines is substantially complete at the exit of the pulse combustor. The additional residence time of 1 to 2 seconds in the freeboard of the PAFBC unit then ensures high carbon conversion and, in turn, high combustion efficiency. A laboratory unit was successfully designed, constructed and tested for over 600 hours to confirm that the PAFBC technology could meet the performance objectives. Subsequently, a 50,000 lb/hr PAFBC demonstration steam boiler was designed, constructed and tested at Clemson University in Clemson, South Carolina. This Final Report presents the detailed results of this extensive and successful PAFBC research, development and demonstration project.

  14. Pulsed atmospheric fluidized bed combustor apparatus

    DOEpatents

    Mansour, Momtaz N.

    1993-10-26

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g., organic and medical waste, drying materials, heating air, calcining and the like.

  15. Biological denitrification in a fluidized bed.

    PubMed

    Narjari, N K; Khilar, K C; Mahajan, S P

    1984-12-01

    A fluidized bed biofilm reactor using sand as the carrier particle was employed to study the effects of superficial velocity on the removal of nitrates as well as on the growth of the biofilm. Velocity was found to affect significantly both nitrate removal and biofilm growth. An analysis based on heterogenous catalysis was used to describe the denitrification process. There is good agreement between analysis and experimental measurements for startup and steady-state operating conditions.

  16. Evaluation of fluid bed heat exchanger optimization parameters. Final report

    SciTech Connect

    Not Available

    1980-03-01

    Uncertainty in the relationship of specific bed material properties to gas-side heat transfer in fluidized beds has inhibited the search for optimum bed materials and has led to over-conservative assumptions in the design of fluid bed heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid bed heat transfer. A total of 31 tests were run with 18 different bed material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized bed evaporator unit was completed for a diesel exhaust heat recovery system. The evaporator heat transfer surface area was substantially reduced while the physical dimensions of the unit increased. Despite the overall increase in unit size, the overall cost was reduced. A study of relative economics associated with bed material selection was conducted. For the fluidized bed evaporator, it was found that zircon sand was the best choice among materials tested in this program, and that the selection of bed material substantially influences the overall system costs. The optimized fluid bed heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid bed heat exchanger; and 50% below a conventional plain tube heat exchanger. The comparisons being made for a 9.6 x 10/sup 6/ Btu/h waste heat boiler. The fluidized bed approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of bed materials for fluidized bed heat exchanger applications, based upon findings of the study reported herein.

  17. Architecture, fracture system, mechanical properties and permeability structure of a fault zone in Lower Triassic sandstone, Upper Rhine Graben

    NASA Astrophysics Data System (ADS)

    Bauer, Johanna F.; Meier, Silke; Philipp, Sonja L.

    2015-04-01

    Close to the western Upper Rhine Graben Main Fault, Alsace, a NNE-SSW-striking fault zone, crosscutting porous, thick bedded Lower Triassic Bunter sandstone was investigated in detail, including its architecture, discontinuity system, mechanical rock properties and implications on its permeability structure and fault zone type. Field observations indicate a three-part fault zone structure including core-, transition- and damage zone. The at least 14 m thick fault core is composed of various slip surfaces and deformation bands, which encompass fractured host rock lenses. When connected, host rock lenses may transport fluids through the core zone. Adjacent transition zones are highly fractured in R1-orientation, show folded beds and contain P1-oriented deformation bands. R1 and P1-fractures are synthetic shear fractures and project with an acute angle (10-20°) toward the fault plane. Only in the damage zone, fault-parallel striking fractures occur. Here, increasing fracture apertures and connectivity may increase the permeability toward the fault core. Mechanical rock properties from 12 rock samples (Young's modulus, uniaxial compressive strength, tensile strength) measured in all the parts of the fault zone, show highest values within the transition zone. In-situ measurements of rebound-hardnesses with a Schmidt-Hammer and analytical approaches, however, indicate that effective Young's moduli are two to sixteen times lower than the Young's moduli of intact rock. Values clearly decrease toward the fault core, even in the transition zone and are in average lower than effective Young's moduli in the damage zone. Although many fault zones in sandstone are sealing structures these field study show, that fault zones in porous sandstone may allow fluid flow.

  18. Shock Interaction with Random Spherical Particle Beds

    NASA Astrophysics Data System (ADS)

    Neal, Chris; Mehta, Yash; Salari, Kambiz; Jackson, Thomas L.; Balachandar, S. "Bala"; Thakur, Siddharth

    2016-11-01

    In this talk we present results on fully resolved simulations of shock interaction with randomly distributed bed of particles. Multiple simulations were carried out by varying the number of particles to isolate the effect of volume fraction. Major focus of these simulations was to understand 1) the effect of the shockwave and volume fraction on the forces experienced by the particles, 2) the effect of particles on the shock wave, and 3) fluid mediated particle-particle interactions. Peak drag force for particles at different volume fractions show a downward trend as the depth of the bed increased. This can be attributed to dissipation of energy as the shockwave travels through the bed of particles. One of the fascinating observations from these simulations was the fluctuations in different quantities due to presence of multiple particles and their random distribution. These are large simulations with hundreds of particles resulting in large amount of data. We present statistical analysis of the data and make relevant observations. Average pressure in the computational domain is computed to characterize the strengths of the reflected and transmitted waves. We also present flow field contour plots to support our observations. U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, under Contract No. DE-NA0002378.

  19. Ice sheets on plastically-yielding beds

    NASA Astrophysics Data System (ADS)

    Hewitt, Ian

    2016-11-01

    Many fast flowing regions of ice sheets are underlain by a layer of water-saturated sediments, or till. The rheology of the till has been the subject of some controversy, with laboratory tests suggesting almost perfectly plastic behaviour (stress independent of strain rate), but many models adopting a pseudo-viscous description. In this work, we consider the behaviour of glaciers underlain by a plastic bed. The ice is treated as a viscous gravity current, on a bed that allows unconstrained slip above a critical yield stress. This simplified description allows rapid sliding, and aims to investigate 'worst-case' scenarios of possible ice-sheet disintegration. The plastic bed results in an approximate ice-sheet geometry that is primarily controlled by force balance, whilst ice velocity is determined from mass conservation (rather than the other way around, as standard models would hold). The stability of various states is considered, and particular attention is given to the pace at which transitions between unstable states can occur. Finally, we observe that the strength of basal tills depends strongly on pore pressure, and combine the model with a description of subglacial hydrology. Implications for the present-day ice sheets in Greenland and Antarctica will be discussed. Funding: ERC Marie Curie FP7 Career Integration Grant.

  20. Reference repository design concept for bedded salt

    SciTech Connect

    Carpenter, D.W.; Martin, R.W.

    1980-10-08

    A reference design concept is presented for the subsurface portions of a nuclear waste repository in bedded salt. General geologic, geotechnical, hydrologic and geochemical data as well as descriptions of the physical systems are provided for use on generic analyses of the pre- and post-sealing performance of repositories in this geologic medium. The geology of bedded salt deposits and the regional and repository horizon stratigraphy are discussed. Structural features of salt beds including discontinuities and dissolution features are presented and their effect on repository performance is discussed. Seismic hazards and the potential effects of earthquakes on underground repositories are presented. The effect on structural stability and worker safety during construction from hydrocarbon and inorganic gases is described. Geohydrologic considerations including regional hydrology, repository scale hydrology and several hydrological failure modes are presented in detail as well as the hydrological considerations that effect repository design. Operational phase performance is discussed with respect to operations, ventilation system, shaft conveyances, waste handling and retrieval systems and receival rates of nuclear waste. Performance analysis of the post sealing period of a nuclear repository is discussed, and parameters to be used in such an analysis are presented along with regulatory constraints. Some judgements are made regarding hydrologic failure scenarios. Finally, the design and licensing process, consistent with the current licensing procedure is described in a format that can be easily understood.

  1. Piloted Ignition Regimes of Wildland Fuel Beds

    NASA Astrophysics Data System (ADS)

    Thomas, J. C.; Simeoni, A.; Colella, F.; Torero, J. L.

    2012-04-01

    Pine needle litters, a key fuel in North American and Mediterranean forest systems, are highly porous fuel beds. They provide a source of continuous fuel medium that can be easily ignited and will sustain flame spread in forest fires. This study is a continuation of previous piloted ignition experimentation [1]. Here, focus was drawn to the influence of airflow in a porous fuel bed for three species: Pinus halepensis, Pinus strobus, and Pinus resinosa. Each needle species is characterized by surface-to-volume ratio and density. The tests samples are characterized by the bulk density, porosity and absorptivity. The needles are subjected to an external radiant heat flux using the FM Global Fire Propagation Apparatus. Ignition delay times and surface temperatures were recorded under a range of different test conditions (basket open area, flow conditions and different level of the radiant heat flux). A comparison of the results indicates that the flow condition must be considered for the modeling of such fuel beds. For conditions where the air flow through the sample is blocked a solid like behavior can be observed. The results show that this cannot be granted for open sample baskets. The goal of this study is to understand the effects, cooling and mixing, of airflow through the porous medium on the time to ignition of the sample and aid in the development of new models for characterizing the ignition behavior.

  2. FBR and RBR particle bed space reactors

    SciTech Connect

    Powell, J.R.; Botts, T.E.

    1983-01-01

    Compact, high-performance nuclear reactor designs based on High-Temperature Gas Reactors (HTGRs) particulate fuel are investigated. The large surface area available with the small-diameter (approx. 500 microns) particulate fuel allows very high power densities (MW's/liter), small temperature differences between fuel and coolant (approx. 10/sup 0/K), high coolant-outlet temperatures (1500 to 3000/sup 0/K, depending on design), and fast reactor startup (approx. 2 to 3 seconds). Two reactor concepts are developed - the Fixed Bed Reactor (FBR), where the fuel particles are packed into a thin annular bed between two porous cylindrical drums, and the Rotating Bed Reactor (RBR), where the fuel particles are held inside a cold rotating (typically approx. 500 rpm) porous cylindrical drum. The FBR can operate steady-state in the closed-cycle He-cooled mode or in the open-cycle H/sub 2/-cooled mode. The RBR will operate only in the open-cycle H/sub 2/-cooled mode.

  3. Characterizing fuels for atmospheric fluidized bed combustion

    SciTech Connect

    Marban, G.; Pis, J.J.; Fuertes, A.B.

    1995-10-01

    A complete methodology for characterizing coal combustion in atmospheric fluidized bed reactors is presented. The methodology comprises studies of fragmentation and particle size variations during combustion, necessary to allow an accurate determination of kinetic parameters and attrition rates. Samples of three different carbonaceous materials (a medium-ash lignite, a medium-ash anthracite and a graphite) were pyrolyzed in N{sub 2} and partially burned in air in a bench-scale fluidized bed reactor at different operating conditions. The particle size distribution, apparent density and number of particles were evaluated by Image Analysis. Additionally, the sphericity factors were calculated. Combustion studies were carried out in batch experiments in the laboratory-scale, fluidized bed reactor at the same operating conditions. The reactor outlet concentrations of O{sub 2}, CO{sub 2}, and CO were monitored continuously. The results indicate that only anthracite particles experienced both primary (due to devolatilization) and secondary (during char combustion) fragmentation. Graphite particles underwent secondary fragmentation, whereas lignite particles did not significantly vary in number during combustion. Size and density variations during combustion suggest that graphite particles burn under regime II, interparticle diffusion being the rate controlling step. On the other hand, anthracite and lignite particles developed an ash layer, which may control combustion. The attrition constants of the medium-ash materials (lignite and anthracite) were found to be very low whereas that of graphite was much higher due mainly to peripheral percolation during combustion.

  4. Status of the fluidized bed unit

    SciTech Connect

    Williams, P.M.; Wade, J.F.

    1994-06-01

    Rocky Flats has a serious mixed waste problem. No technology or company has a license and available facilities to remedy this dilemma. One solution under study is to use a catalytic fluidized bed unit to destroy the combustible portion of the mixed waste. The fluidized bed thermal treatment program at Rocky Flats is building on knowledge gained over twenty years of successful development activity. The FBU has numerous technical advantages over other thermal technologies to treat Rocky Flats` mixed waste, the largest being the lower temperature (700{degrees}C versus 1000{degrees}C) which reduces acid corrosion and mechanical failures and obviates the need for ceramic lining. Successful demonstrations have taken place on bench, pilot, and full-scale tests using radioactive mixed wastes. The program is approaching implementation and licensing of a production-scale fluidized bed system for the safe treatment of mixed waste. The measure for success on this project is the ability to work closely with the community to jointly solve problems and respond to concerns of mixed waste treatment at Rocky Flats.

  5. Ceramic pebble bed development for fusion blankets

    SciTech Connect

    Gierszewski, P.; Kawamura, H.; Donne, M.D.

    1994-12-31

    Research on lithium ceramic breeders has been intensive since the late 1970`s. The bulk material properties of several candidate lithium ceramics are generally available, although there is still much work to be done on properties under irradiation and on overall behavior in blanket modules. Based on these results, lithium ceramic breeders have been selected in many fusion design studies. These lithium ceramics are incorporated into blankets typically as monolithic pellets of packed pebble beds. There is substantial industrial experience with pebble beds made from other ceramics, notably in chemical processes as catalyst supports and grinding media, and in advanced fission reactor fuels. In fusion blankets, the pebble bed form offers several attractive features, including simpler assembly into complex geometry, uniform pore network, and low sensitivity to cracking or irradiation damage. Ceramic breeder pebbles have been a focus for several research groups. In general, the database is similar to that of monolithic pellets for the materials studied: basic production and material property data are available, but the irradiation and engineering database remains sparse.

  6. Size distribution of Amazon River bed sediment

    USGS Publications Warehouse

    Nordin, C.F.; Meade, R.H.; Curtis, W.F.; Bosio, N.J.; Landim, P.M.B.

    1980-01-01

    The first recorded observations of bed material of the Amazon River were made in 1843 by Lt William Lewis Herndon of the US Navy, when he travelled the river from its headwaters to its mouth, sounding its depths, and noting the nature of particles caught in a heavy grease smeared to the bottom of his sounding weight1. He reported the bed material of the river to be mostly sand and fine gravel. Oltman and Ames took samples at a few locations in 1963 and 1964, and reported the bed material at O??bidos, Brazil, to be fine sands, with median diameters ranging from 0.15 to 0.25 mm (ref. 2). We present here a summary of particle-size analyses of samples of streambed material collected from the Amazon River and its major tributaries along a reach of the river from Iquitos in Peru, ???3,500 km above Macapa?? Brazil, to a point 220 km above Macapa??3. ?? 1980 Nature Publishing Group.

  7. Paleotectonic implications of arkose beds in Park Shale (Middle Cambrian), Bridger Range, south-central Montana

    SciTech Connect

    Fryxell, J.C.; Smith, D.L.

    1983-08-01

    The Cambrian System in the Bridger Range of south-central Montana is part of a 450 to 500-m (1475 to 1640-ft) thick transgressive-regressive sequence of fine-grained clastic and carbonate rocks. In south-central Montana, the Park Shale is 50 m (165 ft) of green, micaceous shale with interbedded siltstone at the base and intercalated limestone at the top. However, in the northern Bridger Range, the lower 30 m (100 ft) is a prominent interval of interbedded arkosic sandstone and micaceous shale. These arkosic sandstone beds are localized in the northern Bridger Range and are unknown in the southern Bridgers and in Cambrian outcrops of surrounding areas. The occurrence of Park sandstone beds that contain orthoclase and plagioclase grains and pebbles of quartzofeldspathic gneiss requires 1) the presence of a localized island of Precambrian crystalline rock, an erosional remnant that must have risen at least 200 m (650 ft) above the surrounding Cambrian/Precambrian erosion surface and was exposed above the depositional interface through most of the Middle Cambrian, or 2) an island of Precambrian crystalline rock that was exposed by late Middle Cambrian reactivation of zones of Precambrian structural weakness. The most spatially and lithologically feasible tectonic feature along which late Middle Cambrian movement might have produced an island or series of islands is the Willow Creek-Jefferson Canyon fault zone, along which significant movement occurred during deposition of the LaHood Formation (Precambrian Y); the fault zone structurally divides the northern and southern parts of the Bridger Range, and later Paleozoic movement has been documented along this zone.

  8. New and revisited paleomagnetic data from Permian-Triassic red beds: Two kinematic domains in the west-central Pyrenees

    NASA Astrophysics Data System (ADS)

    Oliva-Urcia, Belén; Pueyo, Emilio L.; Larrasoaña, Juan Cruz; Casas, Antonio M.; Román-Berdiel, Teresa; Van der Voo, Rob; Scholger, Robert

    2012-02-01

    New paleomagnetic results of Permian-Triassic red beds from Bielsa, Aure and Somport-Anayet sectors in the Pyrenean Axial Zone are presented and combined with revisited and reviewed paleomagnetic data from the west-central Pyrenees. The paleomagnetic data from the red beds vary between different sectors that share similar structural position; i.e. whilst all sectors share the existence of a characteristic prefolding component, a Cenozoic postfolding component is found only in one area but not in other areas with similar structural position and kinematics. Previous paleomagnetic data to the west of the studied zone reveal a pre-Turonian remagnetization component, but this secondary component is not found in an area that shares a similar structural position (Aure). This variability suggests that the paleomagnetic behavior is the result of a series of factors related to the particular tectonic history of the region (sedimentation, burial, and deformation during basin inversion) and therefore paleomagnetic data demands careful assessment in order to unravel the kinematics of areas with equivalent structural positions in orogens. However, important kinematic implications that hold in the Pyrenees can be inferred from the restoration of the Permian-Triassic characteristic magnetizations to positions previous to the paleomagnetic rotations recorded by Cretaceous or Cenozoic paleomagnetic data. The restoration reveals on one hand the lack of large rotations in the South Pyrenenan Zone except in the Nogueras area, according to Bates (1989), and on the other hand, the contrasting rotations recorded to the west of the studied zone, in the Paleozoic Basque Massifs (PBM) and the South-Pyrenean Zone, indicating the existence of two different tectonic domains in the west-central sector of the Pyrenees. The strong clockwise rotations postdating the Early Cretaceous remagnetization that are recorded in the PBM and in the North Pyreneean Zone, suggest a late dextral shear

  9. From pore-scale flow measurements towards a Computational Fluid Dynamics prediction of momentum exchange across river bed interface

    NASA Astrophysics Data System (ADS)

    Sambrook Smith, G.; Hardy, R. J.; Best, J.; Blois, G.; Lead, J.

    2010-12-01

    Developing numerical models capable of simulating the hydrodynamics of open-channel flows over rough and within permeable beds is crucial for predicting the morphodynamic evolution of alluvial channels, as well as understanding the complex physical-chemical processes occurring within the subsurface (hyporheic zone) of river beds. However, most current numerical models assume that alluvial streams have an impermeable channel bed, which represents a considerable simplification since experimental observations have shown turbulence within gravel-beds can be significant. Thus, Darcian theory, suitable for low-conductivity porous media, should not be applied within cohesionless gravel-bed rivers. Although the Reynolds Averaged Navier Stokes (RANS) equations can be used to model flow through a porous media if the internal morphology is known, this has rarely been accomplished, and the complexity of the internal morphology of the bed has meant that the normal approach to this problem is to volume-average the NS equations and close them with the Hazen-Dupui-Darcy (HDD) model. However, if the internal morphology of the bed is known a Computational Fluid Dynamics (CFD) approach with a mass flux scaling algorithm (MFSA), which has been developed to include complex bed topography into a numerically stable discretization, can be applied. This allows both time averaged, and time dependent prediction of the flow. Even though these models represent the state-of-the-art, they have yet to be validated, and hence their reliability remains unknown. The lack of appropriate validation data is due to the fact that experimental techniques cannot currently meet the significant challenges required to fully characterize the complex instantaneous turbulent patterns produced within bed pore spaces. To meet this challenge, a novel high-resolution endoscopic particle image velocimetry (E-PIV) technique, capable of collecting data within the pore spaces of a submerged permeable bed, has been

  10. Friction at the bed of Engabreen, Norway

    NASA Astrophysics Data System (ADS)

    Cohen, D.; Iverson, N. R.; Hooyer, T. S.; Jackson, M.; Moore, P. L.

    2001-12-01

    Basal sliding plays an important role in glacier dynamics. In models of temperate-glacier sliding, the local shear traction on the bed is usually assumed to be zero, owing to the thin water film that lubricates the ice-rock interface. In reality, debris beneath glaciers causes friction, but the extent of this friction is poorly known. To measure the local shear traction on the bed of a temperate glacier, we installed an instrumented panel at the bed of Engabreen, Norway, beneath an ice thickness of~230 m. The panel was installed at the top of a vertical shaft accessed from tunnels in the bedrock beneath the glacier, where the Svartisen Subglacial Laboratory is housed. Mounted flush with the glacier bed, the panel contained a flat, disk-shaped, granite tablet (0.33~m diameter), such that debris-bearing ice slid over the tablet with zero form drag. The panel consisted of an aluminum frame that was filled with fiberglass insulation and held together by couplings made of insulating plastic to reduce the heat flux from the vertical shaft. The rock tablet was held in a carriage that rested on thrust bearings with near-zero friction. Sensors in the panel measured the shear traction on the tablet during sliding, pressure in the water film above the tablet, temperature in the panel, total stress normal to the panel, and sliding speed. The shear traction on the rock tablet was significantly higher than predicted by abrasion theory (Hallet), about 0.1~Mpa. Over the duration of the experiment (6~days), this value fluctuated by up to 15%, probably due to large clasts sporadically sliding across the tablet. Water pressure was high, about 2.6~MPa, and sliding speed was irregular but eventually reached a steady value of 0.2~m d-1. Due to thermistor malfunction, the upward heat flux to the ice could not be calculated, but it was probably higher than the background value. The high basal shear traction was likely caused by a thin layer of water-saturated sediment that separated ice

  11. Using borehole images for target-zone evaluation in horizontal wells

    SciTech Connect

    Hurley, N.F.; Carlson, J.L. ); Thorn, D.R. ); Eichelberger, L.W. )

    1994-02-01

    Horizontal wells are rarely horizontal. Instead, operators commonly try to drill such wells into particular rock layers, or target zones, which may or may not be truly horizontal. Thicknesses of target zones commonly range from a few feet to a few tens of feet (1-10 m). Target-zone evaluation concerns whether a horizontal well was successfully located and drilled in a given rock layer. Borehole-imaging logs provide a powerful tool for stratigraphic interpretation and target-zone evaluation in the Austin Chalk, Niobrara Formation, San Andres Formation, and other units. This study uses borehole images generated by Schlumberger's Formation MicroScanner (FMS), a microconductivity logging device. Open fractures and clay-rich interbeds appear as dark, high-conductivity tracers on the FMS log. These traces can be fit with sinusoidal curves and oriented on a computer workstation. The shape of the sinusoidal curve that fits a particular bedding plane tells the interpreter whether the borehole was moving upward or downward through the strata. STRATLOG (trademark of Sierra Geophysics, Inc., a Halliburton Company) software has been used to display borehole profiles by combining FMS data on fracture intensities and bedding-plane intersections with gamma-ray logs, mud logs, and borehole-deviation surveys. To aid in planning future wells, multiple penetrations of the same horizon can be detected and used to calculate highly accurate bedding-plane dips. Fault interpretation, including the detection of rollover beds, it also possible. Finally, stratigraphic interpretation can be combined with observed fractures to determine which rock layers are most highly fractured, and, therefore, should be target zones.9 refs., 5 figs.

  12. Nitrogen removal in a combined system: vertical vegetated bed over horizontal flow sand bed.

    PubMed

    Kantawanichkul, S; Neamkam, P; Shutes, R B

    2001-01-01

    Pig farm wastewater creates various problems in many areas throughout Thailand. Constructed wetland systems are an appropriate, low cost treatment option for tropical countries such as Thailand. In this study, a combined system (a vertical flow bed planted with Cyperus flabelliformis over a horizontal flow sand bed without plants) was used to treat settled pig farm wastewater. This system is suitable for using in farms where land is limited. The average COD and nitrogen loading rate of the vegetated vertical flow bed were 105 g/m2 x d and 11 g/m2 x d respectively. The wastewater was fed intermittently at intervals of 4 hours with a hydraulic loading rate of 3.7 cm/d. The recirculation of the effluent increased total nitrogen (TN) removal efficiency from 71% to 85%. The chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) removal efficiencies were 95% and 98%. Nitrification was significant in vertical flow Cyperus bed, and the concentration of nitrate increased by a factor of 140. The horizontal flow sand bed enhanced COD removal and nitrate reduction was 60%. Plant uptake of nitrogen was 1.1 g N/m2 x d or dry biomass production was 2.8 kg/m2 over 100 days.

  13. Staged fluidized-bed combustion and filter system

    DOEpatents

    Mei, Joseph S.; Halow, John S.

    1994-01-01

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  14. A staged fluidized-bed comubstion and filter system

    SciTech Connect

    Mei, J.S.; Halow, J.S.

    1993-12-31

    A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized- bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gasses into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

  15. Floristic zones and aeroallergen diversity.

    PubMed

    Weber, Richard W

    2003-08-01

    The interplay of geographic, geochemical, and meteorologic factors combines to define distinct floristic zones in North America. Latitude, elevation, Pacific or Atlantic Ocean influence, continental air mass influence, mountains, and hills are contributory geographic factors. Hardiness zones are defined by the nadir of temperature, which strongly affects the survival of individual plant species. There are 12 hardiness zones from the northernmost tundra to the tropics of Mexico. Although it is useful to consider the 10 major floristic zones, the hardiness zones cut across these zones and characterize subregions. A multiplicity of local terrain effects, such as soil porosity and acidity, and sun exposure also impact on plant growth. The ability of plant species, whether woody shrubs and trees, or herbaceous weeds and grasses, to adapt to conditions within the floristic zones determines their range. This article identifies the major aeroallergenic species and the regions in which they are most prevalent.

  16. Effect of bed rest and exercise on body balance

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1974-01-01

    A battery of 11 body balance tests was administered to 7 men before and after 14 days of bedrest. Seven men who had not undergone bed rest served as controls. During bed rest, each subject underwent daily either isotonic, isometric, or no leg exercise. The results showed that, for the bed-rested no exercise, isotonic exercise, and isometric exercise groups, 2 weeks of bed rest produces significant body balance decrements on 3, 4, and 5 of the 11 tests, respectively. Daily leg exercise did not prevent the debilitating effects of bed rest on body balance. After bed rest, balance skill was relearned rapidly so that in most tests, performance had reached prebed-rest levels by the third recovery day. These data suggest that balance impairment is not due to loss of muscular strength in the legs but, perhaps, to a bed-rest-related change in the neurally coded information to postural control centers.

  17. Exposure of Bed Bugs to Metarhizium anisopliae at Different Humidities.

    PubMed

    Ulrich, Kevin R; Feldlaufer, Mark F; Kramer, Matthew; St Leger, Raymond J

    2014-12-01

    Bed bugs Cimex lectularius L. were exposed to conidia (spores) of the entomopathogenic fungus Metarhizium anisopliae by feeding, aerosol spray, or contact with a treated surface. Feeding experiments demonstrated that bed bugs were innately susceptible to this fungus. However, only at 98% humidity were mortality rates high, regardless of whether bed bugs were sprayed with a fungal solution or contacted a treated surface. Mortality in treated bed bugs at ambient humidity did not increase when these bed bugs were kept in aggregation with other bed bugs that had recently blood fed to repletion. Based on these laboratory studies, we conclude that M. anisopliae is a poor pathogen for use in control of bed bugs, particularly at humidities that would likely be encountered under field conditions.

  18. Smartphones and Time Zones

    NASA Astrophysics Data System (ADS)

    Baird, William; Secrest, Jeffery; Padgett, Clifford; Johnson, Wayne; Hagrelius, Claire

    2016-09-01

    Using the Sun to tell time is an ancient idea, but we can take advantage of modern technology to bring it into the 21st century for students in astronomy, physics, or physical science classes. We have employed smartphones, Google Earth, and 3D printing to find the moment of local noon at two widely separated locations. By reviewing GPS time-stamped photos from each place, we are able to illustrate that local noon is longitude-dependent and therefore explain the need for time zones.

  19. Liquid zone seal

    DOEpatents

    Klebanoff, Leonard E.

    2001-01-01

    A seal assembly that provides a means for establishing multiple pressure zones within a system. The seal assembly combines a plate extending from the inner wall of a housing or inner enclosure that intersects with and is immersed in the fluid contained in a well formed in a tray contained within the enclosure. The fluid is a low vapor pressure oil, chemically inert and oxidation resistant. The use of a fluid as the sealing component provides a seal that is self-healing and mechanically robust not subject to normal mechanical wear, breakage, and formation of cracks or pinholes and decouples external mechanical vibrations from internal structural members.

  20. Saturated Zone Colloid Transport

    SciTech Connect

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant retardation