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1

White Sands, Carrizozo Lava Beds, NM  

NASA Technical Reports Server (NTRS)

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.

1973-01-01

2

Bathymetric evolution of sand bed forms under partially standing waves  

E-print Network

Experiments were conducted in a large wave flume where the interaction between water waves and a movable sand bed were investigated. Monochromatic and poly- chromatic waves of specified amplitudes and period were generated ...

Landry, Blake Jude

2004-01-01

3

Coupled changes in sand grain size and sand transport driven by changes in the upstream supply of sand in the Colorado River: relative importance of changes in bed-sand grain size and bed-sand area  

USGS Publications Warehouse

Sand transport in the Colorado River in Marble and Grand canyons was naturally limited by the upstream supply of sand. Prior to the 1963 closure of Glen Canyon Dam, the river exhibited the following four effects of sand supply limitation: (1) hysteresis in sediment concentration, (2) hysteresis in sediment grain size coupled to the hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4) development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Construction and operation of the dam has enhanced the degree to which the first two of these four effects are evident, and has not affected the degree to which the last two effects of sand supply limitation are evident in the Colorado River in Marble and Grand canyons. The first three of the effects involve coupled changes in suspended-sand concentration and grain size that are controlled by changes in the upstream supply of sand. During tributary floods, sand on the bed of the Colorado River fines; this causes the suspended sand to fine and the suspended-sand concentration to increase, even when the discharge of water remains constant. Subsequently, the bed is winnowed of finer sand, the suspended sand coarsens, and the suspended-sand concentration decreases independently of discharge. Also associated with these changes in sand supply are changes in the fraction of the bed that is covered by sand. Thus, suspended-sand concentration in the Colorado River is likely regulated by both changes in the bed-sand grain size and changes in the bed-sand area. A physically based flow and suspended-sediment transport model is developed, tested, and applied to data from the Colorado River to evaluate the relative importance of changes in the bed-sand grain size and changes in the bed-sand area in regulating suspended-sand concentration. Although the model was developed using approximations for steady, uniform flow, and other simplifications that are not met in the Colorado River, the results nevertheless support the idea that changes in bed-sand grain size are much more important than changes in bed-sand area in regulating the concentration of suspended sand.

Topping, D.J.; Rubin, D.M.; Melis, T.S.

2007-01-01

4

20. View of sand filtration bed. Wheelbarrow was used to ...  

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

20. View of sand filtration bed. Wheelbarrow was used to remove schmutzdeck (top, dirty sand layer containing particulate contamination, dead microorganisms and debris) for cleaning and or disposal. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

5

Arsenate removal from water using sand–red mud columns  

Microsoft Academic Search

This study describes experiments in which sorption filters, filled with chemically modified red mud (Bauxsol) or activated Bauxsol (AB) coated sand, are used to remove As(V) (arsenate) from water. Bauxsol-coated sand (BCS) and AB-coated sand (ABCS) are prepared by mixing Bauxsol or AB with wet sand and drying. Samples of the BCS and ABCS are also used in batch experiments

Hülya Genç-Fuhrman; Henrik Bregnhøja; David M McConchie

2005-01-01

6

Oxidative pyrolysis of mixed solid wastes by sand bed and freeboard reaction in a fluidized bed  

Microsoft Academic Search

Oxidative pyrolysis of mixed solid wastes by both sand bed and freeboard reaction in a fluidized bed reactor was investigated. Air was the fluidizing gas (i.e. primary air, injected into the dense solids region) and secondary gas (i.e. injected into the freeboard). The effects were examined of (1) pyrolysis temperature (in both main and secondary combustion chambers) and (2) dimensionless

Ming Yen Wey; Shiann Chin Huang; Cheng Lie Shi

1997-01-01

7

Sand Bed Load in a Brook Trout Stream  

Microsoft Academic Search

An experimental introduction of sand sediment into Hunt Creek in the northern Lower Peninsula of Michigan that increased the bed load 4-5 times resulted in a significant reduction of brook trout (Salvelinus fontinalis) numbers and habitat. The brook trout population declined to less than half its normal abundance. The growth rate of individual fish was not affected. Population adjustment to

Gaylord R. Alexander; Edward A. Hansen

1986-01-01

8

The pyrolysis of oil sands in a fluidized bed at reduced pressure  

Microsoft Academic Search

A fluidized bed pyrolysis reactor system was designed, constructed, and tested at reactor pressures less than atmospheric using mined and crushed oil sands from the Whiterocks deposit of Utah. A 6.0 inch ID fluidized bed reactor was fed oil sand of 7% bitumen saturation on a continuous basis while maintaining a bed height of approximately 12 inches. Spent sand was

1992-01-01

9

Pyrolytic conversion of carbonaceous solids to fuel gas in quartz sand fluidized beds  

Microsoft Academic Search

Particulate carbonaceous solids are pyrolytically converted to fuel gas in a fluidized bed containing quartz sand as the primary inert heat-transfer medium. In addition to the quartz sand, the fluidized bed contains an anti-agglomerating composition consisting of a carbonate or oxide of calcium, magnesium, or barium, or mixtures thereof. The formation of sand agglomerates (viz. clinkers) interfering with fluidized bed

L. T. Fan; W. P. Walawender

1984-01-01

10

Are discontinuous rating curves in sand bedded rivers due to bedform transitions or bed scour?  

NASA Astrophysics Data System (ADS)

Estimating discharge from flow stage in sand-bedded rivers is complicated by non-monotonic relationships between gauge height and discharge. These discontinuous rating curves have an enigmatic region where stage decreases while discharge increases, such that the same stage is apparently associated with two possible discharges. Previous work has shown that this can occur due to changes in bed configuration that reduce roughness and increase flow conveyance. An alternative explanation is that the increase in conveyance is due to enhanced bed scour and changes in cross-section geometry. Here we investigate these two hypotheses using discharge gauge measurements from the San Juan River at Shiprock, New Mexico. We focus on the snowmelt hydrograph of 1941, for which the gauge operator made a unique set of notations indicating the presence of sand boils and sand waves. We use these field observations to calibrate a site-specific model for the flow conditions that create dune, plane and anti-dune bed configurations. For each gauged discharge, we back-calculate cross-section average roughness coefficients and flow conveyance area. From these data we evaluate the relative contribution of changes in bed configuration and cross-section geometry to the observed discontinuities in the stage-discharge relationship. The outcome of this analysis will be useful in modeling flow, and reducing errors in estimating discharge, in large sand-bedded rivers.

Yousfi, Y. M.; Sklar, L. S.; Dawdy, D. R.

2013-12-01

11

Arsenate removal from water using sand--red mud columns.  

PubMed

This study describes experiments in which sorption filters, filled with chemically modified red mud (Bauxsol) or activated Bauxsol (AB) coated sand, are used to remove As(V) (arsenate) from water. Bauxsol-coated sand (BCS) and AB-coated sand (ABCS) are prepared by mixing Bauxsol or AB with wet sand and drying. Samples of the BCS and ABCS are also used in batch experiments to obtain isotherm data. The observed adsorption data fit the Langmuir model well, with adsorption maxima of 3.32 and 1.64 mgg(-1) at pH values of 4.5 and 7.1, respectively for BCS; and of 2.14 mgg(-1) for ABCS at a pH of 7.1. Test results show that higher arsenate adsorption capacities can be achieved for both BCS and ABCS when using the columns compared to results for batch experiments; the difference is greater for BCS. Additional batch tests, carried out for 21 days using BCS to explain the observed discrepancy, show that the equilibrium time previously used in batch experiments was too short because adsorption continued for at least 21 days and reached 87% after 21 days compared to only 35% obtained after 4h. Fixed bed column tests, used to investigate the effects of flow rate and initial arsenate concentration indicate that the process is sensitive to both parameters, with lower flow rates (longer effective residence times in the columns) and initial arsenate concentrations providing better column performance. An examination of the combined effect of potential competing anions (i.e. silicate, phosphate, sulphate and bicarbonate) on the column performance showed that the presence of these anions in tap water slightly decreases arsenate removal. Each breakthrough curve is compared to the Thomas model, and it is found that the model may be applied to estimate the arsenate sorption capacity in columns filled with BCS and ABCS. The data obtained from both batch and column studies indicate that BCS and ABCS filtration could be effectively used to remove arsenate from water, with the latter being more efficient. PMID:15979686

Genç-Fuhrman, Hülya; Bregnhøj, Henrik; McConchie, David

2005-08-01

12

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

USGS Publications Warehouse

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.

Gaeuman, D.; Jacobson, R. B.

2006-01-01

13

Evaluation of propane flaming for reducing bacterial counts in sand bedding.  

PubMed

An experiment was conducted on a commercial dairy farm to determine the effects of propane flaming on bacterial populations of common environmental mastitis pathogens in recycled sand bedding. One row of freestalls was flamed within 12 h after recycled bedding was added to stalls and then daily for the next 6 d. Bedding in a control row of freestalls was untreated. Stalls received the same treatment for 3 consecutive weeks. After 3 wk, bedding treatments were changed between rows in a switchback design. The daily movement of the 760°C propane-fueled flame at 3.2 km/h over the surface of recycled sand bedding in stalls had a positive effect by reducing mastitis pathogen loads at different depths of bedding in a pathogen-specific manner. The greatest reduction of mastitis pathogen populations by flaming was on the surface 25 mm of recycled sand. Reductions in bacterial counts in deeper layers were less consistent. Bacterial populations in both flamed and control sand bedding were lower on the surface 25 mm compared with sand at a depth of 50 to 75 mm. The effects of subsequent flaming of sand over a week also differed among pathogens. In general, mastitis pathogens were reduced the most on the day that recycled sand was added to stalls, and flaming was less effective as sand bedding was in stalls over a 6-d period. The use of propane flaming of recycled sand was shown to have potential as a practice to control mastitis pathogen populations in bedding. The greatest advantage afforded by flaming was on the surface of bedding, with inconsistent effects deeper in the stalls. Flaming was more effective in controlling bacterial populations in fresh recycled sand than in sand after several days use PMID:22863101

Hogan, J S; Raubenolt, L; McCormick, J L; Weiss, W P

2012-10-01

14

Density stratification effects in sand-bed rivers  

USGS Publications Warehouse

In this paper the effects of density stratification in sand-bed rivers are studied by the application of a model of vertical velocity and concentration profiles, coupled through the use of a turbulence closure that retains the buoyancy terms. By making the governing equations dimensionless, it is revealed that the slope is the additional dimensionless parameter introduced by inclusion of the buoyancy terms. The primary new finding is that in general density stratification effects tend to be greater in large, low-slope rivers than in their smaller, steeper brethren. Under high flow conditions the total suspended load and size distribution of suspended sediment can be significantly affected by density stratification, and should be accounted for in any general theory of suspended transport. ?? ASCE.

Wright, S.; Parker, G.

2004-01-01

15

The pyrolysis of oil sands in a fluidized bed at reduced pressure  

SciTech Connect

A fluidized bed pyrolysis reactor system was designed, constructed, and tested at reactor pressures less than atmospheric using mined and crushed oil sands from the Whiterocks deposit of Utah. A 6.0 inch ID fluidized bed reactor was fed oil sand of 7% bitumen saturation on a continuous basis while maintaining a bed height of approximately 12 inches. Spent sand was withdrawn using a modified nonmechanical L valve. The characteristics of bed pressure drop, [Delta]P[sub B], versus superficial gas velocity, U, were determined during fluidization and defluidization of spent sand using laboratory air. A proposed method for interpreting the minimum fluidization gas velocity, U[sub mf], from [Delta]P[sub B] versus U curves for multisized particles at reduced pressure was tested. U[sub mf] values were consistent with predictive correlations in the literature. The relationship, U[sub mf] T[sup 0.27] = a constant, was tested and found to be valid from 295 K to 559 K for spent sand fluidized by air. The reactor used propane for heating and the hot propane combustion product gases for fluidization during pyrolysis. Liquid products were condensed and filtered using commercial basket strainers modified with water cooling coils. Material balances of 90% or more were obtained for pyrolysis experiments at 450[degrees]C, 475[degrees]C, and 500[degrees]C. The optimum pyrolysis temperature for liquid yields was found to be 475[degrees]C at average retention times of thirty minutes or more. For pyrolysis temperatures of 475[degrees]C or lower, recovered oil sand pyrolysis products were 88 wt% liquid, 9 wt% coke, and 3 wt% gas. Liquid yields from the fluidized bed pyrolysis of Whiterocks oil sands at reduced pressure were greater than reported yields from a rotary kiln or an atmospheric pressure fluidized bed. Coke on the spent sand was about 0.6 wt% of the spent sand and represented about 8 wt% of the bitumen pyrolyzed.

Fletcher, J.V.

1992-01-01

16

Experiments on the Evolution of Sand Bed Forms for Varying Degrees of Supply Limitation  

NASA Astrophysics Data System (ADS)

The advanced age and impending decommissioning of many dams have brought increased attention to the fate of sediments stored in reservoirs. In many cases, fine sediments are reintroduced to coarse substrates that have large volumes of pore space available for storage after having sediments removed by years of sediment-starved flow. Recent research has found that the fine sediment elevation relative to the coarse substrate significantly alters bed surface roughness, turbulence characteristics, the mobility of the fine sediment, and consequently sediment transport rates and sediment bed forms that move over and through these coarse substrates. The roughness of the bed surface is an important parameter for the prediction of bulk flow and sediment transport rates. In order to calculate sediment transport rates, bed shear stresses are typically adjusted for drag exerted by the flow on macro roughness elements, which are related here to the protrusion of coarse substrate particles and sediment bed forms. Also, the partial mobility (or supply limitation) of sediment yields bed forms that differ from those observed for uniform bed material. Hence, a proper understanding of the interactions between near-bed flow structure, sediment transport rates, and bed surface elevation is needed to adequately determine the downstream impact of fine sediment releases from reservoirs. Recent experiments at the USDA-ARS-National Sedimentation Laboratory in a sediment-recirculating flume (15 m long, 0.36 m wide, and 0.45 m deep) were carried out to elucidate turbulence and sand transport over and through coarse gravel substrates. The median diameter of the sand was 0.3 mm, and that of the gravel was 35 mm. This paper presents results on the change in bed form types with increasing sand elevation relative to the coarse gravel substrate and for Froude numbers ranging from about 0.1 to 0.6. The mean sand elevation was varied between 5 cm below the top of the gravel and the top of the gravel. The bed level was measured using both an acoustic sensor and stereo photogrammetry. The acoustic sensor provided bed elevation transects along the channel centerline, whereas digital elevation models with a horizontal grid size of 0.25x0.25 mm were derived from the stereo images. At low mean sand elevations an individual, low-relief dune-like bed form initially developed for larger Froude numbers. Groups of increasingly numerous low-relief bed forms developed when increasing mean sand elevation. The tops of the bed forms were located at an elevation similar to those of the higher gravel tops.

Langendoen, E. J.; Wren, D. G.; Kuhnle, R. A.

2011-12-01

17

Upper Cretaceous oceanic red beds in southern Tibet: Lithofacies, environments and colour origin  

Microsoft Academic Search

Application of mineralogy, geochemistry, sedimentary petrology, and sedimentology methods result in better understanding of\\u000a the genesis and paleoenvironmens of the Upper Cretaceous oceanic red beds exposed in southern Tibet. The red beds comprise\\u000a the Chungde Formation. Nine lithofacies recognized within this formation are: red foraminiferal packstone\\/grainstone, red\\u000a microfossils wackestone, red marlstone with microfossils, red marlstone, red to variegated floatstone and

Xiumian Hu; Chengshan Wang; Xianghui Li; Luba Jansa

2006-01-01

18

Channel bed evolution and sediment transport under declining sand inputs  

E-print Network

of Mount Pinatubo, Philippines. As sediment inputs declined from 1996 to 2003, surface grain size increased-dominated transport zones [Ikeda and Iseya, 1988]. [3] The June 1991 eruption of Mount Pinatubo covered 33 [Major et al., 1996; Scott et al., 1996]. The abrupt basin- wide increase in sand loading

Montgomery, David R.

19

Large Woody Debris Structures for Sand-Bed Channels  

Microsoft Academic Search

Described is a method for channel erosion control and habitat rehabilitation featuring intermittent placement of structures made of large woody debris. This method is expressly tailored to address severe problems typical of incised channels with little sediment coarser than sand. In these types of environments, buoyancy forces are typically more important factors in woody debris stability than fluid drag. Buoyant

F. Douglas Shields

2004-01-01

20

General Suppression of Escherichia coli O157:H7 in Sand-Based Dairy Livestock Bedding? †  

PubMed Central

Sand bedding material is frequently used in dairy operations to reduce the occurrence of mastitis and enhance cow comfort. One objective of this work was to determine if sand-based bedding also supported the microbiologically based suppression of an introduced bacterial pathogen. Bedding samples were collected in summer, fall, and winter from various locations within a dairy operation and tested for their ability to suppress introduced populations of Escherichia coli O157:H7. All sources of bedding displayed a heat-sensitive suppressiveness to the pathogen. Differences in suppressiveness were also noted between different samples at room temperature. At just 1 day postinoculation (dpi), the recycled sand bedding catalyzed up to a 1,000-fold reduction in E. coli counts, typically 10-fold greater than the reduction achieved with other substrates, depending on the sampling date. All bedding substrates were able to reduce E. coli populations by over 10,000-fold within 7 to 15 dpi, regardless of sampling date. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to identify bacterial populations potentially associated with the noted suppression of E. coli O157:H7 in sand bedding. Eleven terminal restriction fragments (TRFs) were overrepresented in paired comparisons of suppressive and nonsuppressive specimens at multiple sampling points, indicating that they may represent environmentally stable populations of pathogen-suppressing bacteria. Cloning and sequencing of these TRFs indicated that they represent a diverse subset of bacteria, belonging to the Cytophaga-Flexibacter-Bacteroidetes, Gammaproteobacteria, and Firmicutes, only a few of which have previously been identified in livestock manure. Such data indicate that microbial suppression may be harnessed to develop new options for mitigating the risk and dispersal of zoonotic bacterial pathogens on dairy farms. PMID:21257815

Westphal, Andreas; Williams, Michele L.; Baysal-Gurel, Fulya; LeJeune, Jeffrey T.; McSpadden Gardener, Brian B.

2011-01-01

21

Colorado River sediment transport: 2. Systematic bed-elevation and grain-size effects of sand supply limitation  

Microsoft Academic Search

The Colorado River in Marble and Grand Canyons displays evidence of annual supply limitation with respect to sand both prior to [Topping et al., this issue] and after the closure of Glen Canyon Dam in 1963. Systematic changes in bed elevation and systematic coupled changes in suspended-sand concentration and grain size result from this supply limitation. During floods, sand supply

David J. Topping; Ingrid C. Corson

2000-01-01

22

Near-bed turbulence and relict waveformed sand ripples: Observations from the inner shelf  

Microsoft Academic Search

Results are presented from a field investigation of near-bed turbulence above degrading waveformed sand ripples in 17-m water depth on the inner shelf. The heights of the 50-cm wavelength primary ripples were about 5 cm at the start of the observation period, and decreased by a factor of 2 within 15 days. The principal degradation mechanism involved fish making pits

Alex E. Hay

2008-01-01

23

Managing vegetation on peat-sand filter beds for wastewater disposal. Forest Service research note  

SciTech Connect

Five species of grass, one sedge, and cattail were grown on a peat-sand filter bed irrigated with sewage effluent. Yields, uptake of nitrogen and phosphorus, and lodging problems were determined for all species when grown to various heights ranging from 5 to 75 cm.

Elling, A.E.

1985-01-01

24

Response of fishes and aquatic habitats to sand-bed stream restoration using large woody debris  

Microsoft Academic Search

Effects of habitat rehabilitation of Little Topashaw Creek, a sinuous, sand-bed stream draining 37 km2 in northwest Mississippi are described. The rehabilitation project consisted of placing 72 large woody debris structures along eroding concave banks and planting 4000 willow cuttings in sandbars. Response was measured by monitoring flow, channel geometry, physical aquatic habitat, and fish populations. Initially, debris structures reduced

F. Douglas Shields Jr.; Scott S. Knight; Nathalie Morin; Joanne Blank

2003-01-01

25

Influence of large woody debris on morphological evolution of incised, sand-bed channels  

Microsoft Academic Search

This paper documents the influence of Large Woody Debris (LWD) on the morphological evolution of unstable, degrading, sand-bed rivers in the Yazoo Basin, North Mississippi, USA. The study was performed as part of the Demonstration Erosion Control (DEC) project. Twenty-three river reaches were studied, with the aim of determining whether the presence of LWD was beneficial or detrimental to the

N. P. Wallerstein; C. R. Thorne

2004-01-01

26

The Unified Gravel-Sand (TUGS) Model: Simulating Sediment Transport and Gravel\\/Sand Grain Size Distributions in Gravel-Bedded Rivers  

Microsoft Academic Search

This paper presents The Unified Gravel-Sand (TUGS) model that simulates the transport, erosion, and deposition of both gravel and sand. TUGS model employs the surface-based bed load equation of Wilcock and Crowe (2003) and links grain size distributions in the bed load, surface layer, and subsurface with the gravel transfer function of Hoey and Ferguson (1994) and Toro-Escobar et al.

Yantao Cui

2007-01-01

27

Colorado River sediment transport 2. Systematic bed-elevation and grain-size effects of sand supply limitation  

USGS Publications Warehouse

The Colorado River in Marble and Grand Canyons displays evidence of annual supply limitation with respect to sand both prior to [Topping et al., this issue] and after the closure of Glen Canyon Dam in 1963. Systematic changes in bed elevation and systematic coupled changes in suspended-sand concentration and grain size result from this supply limitation. During floods, sand supply limitation either causes or modifies a lag between the time of maximum discharge and the time of either maximum or minimum (depending on reach geometry) bed elevation. If, at a cross section where the bed aggrades with increasing flow, the maximum bed elevation is observed to lead the peak or the receding limb of a flood, then this observed response of the bed is due to sand supply limitation. Sand supply limitation also leads to the systematic evolution of sand grain size (both on the bed and in suspension) in the Colorado River. Sand input during a tributary flood travels down the Colorado River as an elongating sediment wave, with the finest sizes (because of their lower settling velocities) traveling the fastest. As the fine front of a sediment wave arrives at a given location, the bed fines and suspended-sand concentrations increase in response to the enhanced upstream supply of finer sand. Then, as the front of the sediment wave passes that location, the bed is winnowed and suspended-sand concentrations decrease in response to the depletion of the upstream supply of finer sand. The grain-size effects of depletion of the upstream sand supply are most obvious during periods of higher dam releases (e.g, the 1996 flood experiment and the 1997 test flow). Because of substantial changes in the grain-size distribution of the bed, stable relationships between the discharge of water and sand-transport rates (i.e., stable sand rating curves) are precluded. Sand budgets in a supply-limited river like the Colorado River can only be constructed through inclusion of the physical processes that couple changes in bed-sediment grain size to changes in sand-transport rates.

Topping, D.J.; Rubin, D.M.; Nelson, J.M.; Kinzel, P. J., III; Corson, I.C.

2000-01-01

28

Discovery of radiolaria from Upper Cretaceous Oceanic Red Beds in Daba, Kangmar and its paleogeographic implication  

Microsoft Academic Search

A group of varicolored marine deposits, including red colored beds, are widespread in the Kangmar area, southern Tibet. They are lithologically similar to the Upper Cretaceous Oceanic Red Beds (CORBs) (the Chuangde Formation) outcropping at other localities in southern Tibet. At Daba locality, they are mainly composed of intercalated pelagic red clays and reddish colored pelagic limestones. Micropaleontologic study of

Li Guobiao; Jansa Luba; Wan Xiaoqiao; Pan Mao; Xiu Di; Xie Dan

29

Bed load and suspended load contributions to migrating sand dunes in equilibrium  

NASA Astrophysics Data System (ADS)

dominate the bed of sand rivers and are of central importance in predicting flow roughness and water levels. The present study has focused on the details of flow and sediment dynamics along migrating sand dunes in equilibrium. Using a recently developed acoustic system (Acoustic Concentration and Velocity Profiler), new insights are obtained in the behavior of the bed and the suspended load transport along mobile dunes. Our data have illustrated that, due to the presence of a dense sediment layer close to the bed and migrating secondary bedforms over the stoss side of the dune toward the dune crest, the near-bed flow and sediment processes are significantly different from the near-bed flow and sediment dynamics measured over fixed dunes. It was observed that the shape of the total sediment transport distribution along dunes is mainly dominated by the bed load transport, although the bed load and the suspended load transport are of the same order of magnitude. This means that it was especially the bed load transport that is responsible for the continuous erosion and deposition of sediment along the migrating dunes. Whereas the bed load is entirely captured in the dune with zero transport at the flow reattachment point, a significant part of the suspended load is advected to the downstream dune depending on the flow conditions. For the two flow conditions measured, the bypass fraction was about 10% for flow with a Froude number (Fr) of 0.41 and 27% for flow with Froude number of 0.51. This means that respectively 90% (for the Fr = 0.41 flow) and 73% (for the Fr = 0.51 flow) of the total sediment load that arrived at the dune crests contributed to the migration of the dunes.

Naqshband, S.; Ribberink, J. S.; Hurther, D.; Hulscher, S. J. M. H.

2014-05-01

30

Aeolian Sand Transport in the Planetary Context: Respective Roles of Aerodynamic and Bed-Dilatancy Thresholds  

NASA Technical Reports Server (NTRS)

The traditional view of aeolian sand transport generally estimates flux from the perspective of aerodynamic forces creating the airborne grain population, although it has been recognized that "reptation" causes a significant part of the total airborne flux; reptation involves both ballistic injection of grains into the air stream by the impact of saltating grains as well as the "nudging" of surface grains into a creeping motion. Whilst aerodynamic forces may initiate sand motion, it is proposed here that within a fully-matured grain cloud, flux is actually governed by two thresholds: an aerodynamic threshold, and a bed-dilatancy threshold. It is the latter which controls the reptation population, and its significance increases proportionally with transport energy. Because we only have experience with terrestrial sand transport, extrapolations of aeolian theory to Mars and Venus have adjusted only the aerodynamic factor, taking gravitational forces and atmospheric density as the prime variables in the aerodynamic equations, but neglecting reptation. The basis for our perspective on the importance of reptation and bed dilatancy is a set of experiments that were designed to simulate sand transport across the surface of a martian dune. Using a modified sporting crossbow in which a sand-impelling sabot replaced the bolt-firing mechanism, individual grains of sand were fired at loose sand targets with glancing angles typical of saltation impact; grains were projected at about 80 m/s to simulate velocities commensurate with those predicted for extreme martian aeolian conditions. The sabot impelling method permitted study of individual impacts without the masking effect of bed mobilization encountered in wind-tunnel studies. At these martian impact velocities, grains produced small craters formed by the ejection of several hundred grains from the bed. Unexpectedly, the craters were not elongated, despite glancing impact; the craters were very close to circular in planform. High-speed photography showed them to grow in both diameter and depth after the impactor had ricochetted from the crater site. The delayed response of the bed was "explosive" in nature, and created a miniature ejecta curtain spreading upward and outward for many centimeters for impact of 100-300 micron-diameter grains into similar material. Elastic energy deposited in the bed by the impacting grain creates a subsurface stress regime or "quasi-Boussinesq" compression field. Elastic recovery of the bed occurs by dilatancy; shear stresses suddenly convert the grains from closed to open packing, and grains are consequently able to eject themselves forcefully from the impact site. Random jostling of the grains causes radial homogenization of stress vectors and a resulting circular crater. There is a great temptation to draw parallels with cratering produced by meteorite impacts, but a rigorous search for common modelling ground between the two phenomena has not been conducted at this time. For every impact of an aerodynamically energized grain, there are several hundred grains ejected into the wind for the high-energy transport that might occur on Mars. Many of these grains will themselves become subject to the boundary layer's aerodynamic lift forces (their motion will not immediately die and add to the creep population), and these grains will become indistinguishable from those lifted entirely by aerodynamic forces. As each grain impacts the bed, it will eject even more grains into the flow. A cascading effect will take place, but because it must be finite in its growth, damping will occur as the number of grains set in motion causes mid-air collisions that prevent much of the impact energy from reaching the surface of the bed -thus creating a dynamic equilibrium in a high-density saltation cloud. It is apparent that for a given impact energy, the stress field permits a smaller volume of grains to convert to open packing as the size of the bed grains increases, or as the energy of the "percussive" grain decreases

Marshall, J. R.; Borucki, J.; Bratton, C.

1999-01-01

31

Aeolian Sand Transport in the Planetary Context: Respective Roles of Aerodynamic and Bed-Dilatancy Thresholds  

NASA Astrophysics Data System (ADS)

The traditional view of aeolian sand transport generally estimates flux from the perspective of aerodynamic forces creating the airborne grain population, although it has been recognized that "reptation" causes a significant part of the total airborne flux; reptation involves both ballistic injection of grains into the air stream by the impact of saltating grains as well as the "nudging" of surface grains into a creeping motion. Whilst aerodynamic forces may initiate sand motion, it is proposed here that within a fully-matured grain cloud, flux is actually governed by two thresholds: an aerodynamic threshold, and a bed-dilatancy threshold. It is the latter which controls the reptation population, and its significance increases proportionally with transport energy. Because we only have experience with terrestrial sand transport, extrapolations of aeolian theory to Mars and Venus have adjusted only the aerodynamic factor, taking gravitational forces and atmospheric density as the prime variables in the aerodynamic equations, but neglecting reptation. The basis for our perspective on the importance of reptation and bed dilatancy is a set of experiments that were designed to simulate sand transport across the surface of a martian dune. Using a modified sporting crossbow in which a sand-impelling sabot replaced the bolt-firing mechanism, individual grains of sand were fired at loose sand targets with glancing angles typical of saltation impact; grains were projected at about 80 m/s to simulate velocities commensurate with those predicted for extreme martian aeolian conditions. The sabot impelling method permitted study of individual impacts without the masking effect of bed mobilization encountered in wind-tunnel studies. At these martian impact velocities, grains produced small craters formed by the ejection of several hundred grains from the bed. Unexpectedly, the craters were not elongated, despite glancing impact; the craters were very close to circular in planform. High-speed photography showed them to grow in both diameter and depth after the impactor had ricochetted from the crater site. The delayed response of the bed was "explosive" in nature, and created a miniature ejecta curtain spreading upward and outward for many centimeters for impact of 100-300 micron-diameter grains into similar material. Elastic energy deposited in the bed by the impacting grain creates a subsurface stress regime or "quasi-Boussinesq" compression field. Elastic recovery of the bed occurs by dilatancy; shear stresses suddenly convert the grains from closed to open packing, and grains are consequently able to eject themselves forcefully from the impact site. Random jostling of the grains causes radial homogenization of stress vectors and a resulting circular crater. There is a great temptation to draw parallels with cratering produced by meteorite impacts, but a rigorous search for common modelling ground between the two phenomena has not been conducted at this time. For every impact of an aerodynamically energized grain, there are several hundred grains ejected into the wind for the high-energy transport that might occur on Mars. Many of these grains will themselves become subject to the boundary layer's aerodynamic lift forces (their motion will not immediately die and add to the creep population), and these grains will become indistinguishable from those lifted entirely by aerodynamic forces. As each grain impacts the bed, it will eject even more grains into the flow. A cascading effect will take place, but because it must be finite in its growth, damping will occur as the number of grains set in motion causes mid-air collisions that prevent much of the impact energy from reaching the surface of the bed -thus creating a dynamic equilibrium in a high-density saltation cloud. It is apparent that for a given impact energy, the stress field permits a smaller volume of grains to convert to open packing as the size of the bed grains increases, or as the energy of the "percussive" grain decreases

Marshall, J. R.; Borucki, J.; Bratton, C.

1999-09-01

32

Laboratory study of sand bed forms induced by solitary waves in shallow water  

NASA Astrophysics Data System (ADS)

The surface profile of water waves propagating in shoaling water approaches the solitary waveform before wave breaking. The effect of the high non-linearity of solitary waves may be very significant on bed forms induced in the nearshore zone. In this study, experiments on bed form generation beneath solitary waves are carried out in a 10-m-long flume used in resonant mode. Solitary waves are generated in shallow water on the background of a standing harmonic wave. One solitary wave (soliton) propagates in each direction of the flume on the time period of the flow, above an initially flat sandy bed. Ripples form rapidly on the bed and a strong interaction with the free surface occurs. The amplitude of the soliton and the phase shift between the soliton and the harmonic wave decrease with time, while the ripple amplitude increases. The amplitude of the harmonic wave is not affected by the ripples. The final ripple wavelength is about 1000 times the sand median diameter. Bars with superimposed ripples appear, with bar crests being positioned beneath the nodes of the standing wave, when bars form with crests beneath the antinodes of surface wave for standing waves without solitons. The Eulerian drift distribution in the flume is not affected by the propagation of solitons. We propose an energy balance for solitons propagating in shallow water above flat beds in which a term for the dissipation due to sand ripples is introduced, which defines a coefficient of interaction between solitons and ripples.

Marin, FrançOis; Abcha, Nizar; Brossard, JéRôMe; Ezersky, Alexander B.

2005-12-01

33

Relationship of Fish Mesohabitat to Flow in a Sand-Bed Southwestern River  

Microsoft Academic Search

We quantified the availability and utilization of habitat types by eight small-bodied cyprinid fish species, including the federally threatened Pecos bluntnose shiner Notropis simus pecosensis, in the Pecos River, New Mexico. The Pecos River is a medium-sized, sand-bed river with a highly variable hydrograph and some reaches characterized by historic and recent periods of flow intermittency. Fish habitat was described

Jon W. Kehmeier; Richard A. Valdez; C. Nicolas Medley; Orrin B. Myers

2007-01-01

34

Sludge dewatering by sand-drying bed coupled with electrodewatering at various potentials  

Microsoft Academic Search

Large amounts of water in sludge from wastewater treatment plants directly translate into high transport and handling costs. In this study, a laboratory scale sludge sand-drying bed was coupled with an electro-dewatering process to investigate the trends of dewatering at variable voltage potentials. There was a two-fold increase of dry solid (DS) content in final sludge cake when the applied

A. T. Pham; M. Sillanpää; J. Virkutyte

2010-01-01

35

Development and design of a fluidized bed\\/upflow sand filter configuration for use in recirculating aquaculture systems  

Microsoft Academic Search

A fluidized bed\\/upflow sand filter configuration, was developed and designed for utilization in recirculating aquaculture system, specifically the soft-shell crab and soft-shell crawfish industries. These filters were selected and designed because of their ability to withstand clogging and still maintain high levels of water quality for aquaculture production. The effectiveness of sand grain size was used to evaluate fluidized bed

1988-01-01

36

Characterisation of sand transport in gravel-bed rivers using iron slag dated by historical studies  

NASA Astrophysics Data System (ADS)

Considerable quantities of iron-smelting slag are present in the bed of the Ardennian rivers. These waste products come from hundreds of ironworks (mainly blast furnaces and finery forges) built close to different-sized rivers between the 14th and the 19th centuries. In general, slag was crushed by hammers, sorted and piled up in heaps around the furnaces, generally onto the floodplains. Furthermore, some archives mention that they were sometimes thrown out directly into the rivers. This means that for centuries, slag elements have been swept away by floods, mixed with the sediment and spread out along river courses. Due to their distinctive appearance, slag particles are easily recognizable among the natural elements. Thanks to many historical studies conducted on the early iron industry, we are able to date quite precisely the inception and the periods of activity of the different sites established in the catchments. These data are indispensable in order to use slag as a tracer to quantify the particles' velocity in rivers. Downstream of ironworks, samples of sand have been collected in the surface layer of many gravel-bed rivers. Then, the slag concentration of each sample has been measured in the coarse sand fraction. The representation of the longitudinal evolution of slag concentration in these rivers permits the dispersion of slag to be analysed, the relative bed-material discharges at confluences to be quantified and the velocity of coarse sand to be determined. A survey of the bedload discharge in the Ardennian rivers established that more than 90 % of the bedload transport consists of coarse sand grains that are transported on the bottom of the bed. However, in the literature, this grain-size fraction is generally not considered in bedload discharge estimations because the sandy particles are very difficult to tag and to recover. Consequently, the huge amounts of slag injected in rivers several centuries ago can be considered as a very useful opportunity to characterise the sand transport in gravel-bed rivers.

Houbrechts, G.; Levecq, Y.; Petit, F.

2012-04-01

37

Evaluation of an experimental LiDAR for surveying a shallow, braided, sand-bedded river  

USGS Publications Warehouse

Reaches of a shallow (<1.0m), braided, sand-bedded river were surveyed in 2002 and 2005 with the National Aeronautics and Space Administration's Experimental Advanced Airborne Research LiDAR (EAARL) and concurrently with conventional survey-grade, real-time kinematic, global positioning system technology. The laser pulses transmitted by the EAARL instrument and the return backscatter waveforms from exposed sand and submerged sand targets in the river were completely digitized and stored for postflight processing. The vertical mapping accuracy of the EAARL was evaluated by comparing the ellipsoidal heights computed from ranging measurements made using an EAARL terrestrial algorithm to nearby (<0.5m apart) ground-truth ellipsoidal heights. After correcting for apparent systematic bias in the surveys, the root mean square error of these heights with the terrestrial algorithm in the 2002 survey was 0.11m for the 26 measurements taken on exposed sand and 0.18m for the 59 measurements taken on submerged sand. In the 2005 survey, the root mean square error was 0.18m for 92 measurements taken on exposed sand and 0.24m for 434 measurements on submerged sand. In submerged areas the waveforms were complicated by reflections from the surface, water column entrained turbidity, and potentially the riverbed. When applied to these waveforms, especially in depths greater than 0.4m, the terrestrial algorithm calculated the range above the riverbed. A bathymetric algorithm has been developed to approximate the position of the riverbed in these convolved waveforms and preliminary results are encouraging. ?? 2007 ASCE.

Kinzel, P.J.; Wright, C.W.; Nelson, J.M.; Burman, A.R.

2007-01-01

38

Pyrolysis of Uinta Basin Oil Sands in fluidized bed and rotary kiln reactors  

SciTech Connect

A pilot-scale fluidized bed reactor (FBR) was used to pyrolyze the mined and crushed ore from the PR Spring oil sands deposit which is located in the Uinta Basin of Utah. Liquid yields of approximately 80 wt% of the bitumen fed to the reactor were obtained. This compares to 55-70 wt% obtained from smaller laboratory scale fluidized bed reactors and a pilot-scale rotary kiln. The product yields and distributions exhibited no discernable trends with reactor temperature or solids retention time. The liquid products obtained from the pilot-scale fluidized bed reactor were upgraded compared to the bitumen in terms of volatility, viscosity, molecular weight, and metals (Ni and V) content. The nitrogen and sulphur contents of the total liquid products were also reduced relative to the bitumen. A comparison of oil sands pyrolysis yields from a pilot scale FBR and a rotary kiln of the same diameter (15.2 cm) was made. Under similar pyrolysis conditions, the rotary kiln produced a slightly more upgraded product but at lower total liquid yields. Kinetic modeling of the various reactors indicates that the pilot-scale FBR product distributions may be explained using a simplified two-reaction scheme. It is proposed that secondary cracking is suppressed in the large diameter FBR due to elimination of slugging and the superior quality of fluidization in the reactor. More experimental studies with the rotary kiln and an economic evaluation will be required before concluding which reactor is preferred for the thermal recovery process.

Nagpal, S.; Fletcher, J.V.; Hanson, F.V. [Univ. of Utah, Salt Lake City, UT (United States)

1995-12-31

39

Validating Experimental Bedform Dynamics on Cohesive Sand-Mud Beds in the Dee Estuary  

NASA Astrophysics Data System (ADS)

Recent laboratory experiments and field measurements have shown that small quantities of cohesive clay, and in particular 'sticky' biological polymers, within a sandy substrate dramatically reduce the development rate of sedimentary bedforms, with major implications for sediment transport rate calculations and process interpretations from the sedimentary record. FURTHER INFORMATION Flow and sediment transport predictions from sedimentary structures found in modern estuaries and within estuarine geological systems are impeded by an almost complete lack of process-based knowledge of the behaviour of natural sediments that consist of mixtures of cohesionless sand and biologically-active cohesive mud. Indeed, existing predictive models are largely based on non-organic cohesionless sands, despite the fact that mud, in pure form or mixed with sand, is the most common sediment on Earth and also the most biologically active interface across a range of Earth-surface environments, including rivers and shallow seas. The multidisciplinary COHBED project uses state-of-the-art laboratory and field technologies to measure the erosional properties of mixed cohesive sediment beds and the formation and stability of sedimentary bedforms on these beds, integrating the key physical and biological processes that govern bed evolution. The development of current ripples on cohesive mixed sediment beds was investigated as a function of physical control on bed cohesion versus biological control on bed cohesion. These investigations included laboratory flume experiments in the Hydrodynamics Laboratory (Bangor University) and field experiments in the Dee estuary (at West Kirby near Liverpool). The flume experiments showed that winnowing of fine-grained cohesive sediment, including biological stabilisers, is an important process affecting the development rate, size and shape of the cohesive bedforms. The ripples developed progressively slower as the kaolin clay fraction in the sandy substrate bed was increased. The same result was obtained for xanthan gum, which is a proxy for biological polymers produced by microphytobenthos. Yet, the xanthan gum was several orders more effective in slowing down ripple development than kaolin clay, suggesting that the cohesive forces for biological polymers are much higher than for clay minerals, and that sedimentological process models should refocus on biostabilisation processes. The first results of the field experiments show that the winnowing of fines from developing ripples and the slowing down of current ripple development in mixed cohesive sediment is mimicked on intertidal flats in the Dee estuary. In particular, these field data revealed that current ripples in cohesive sediment are smaller with more two-dimensional crestlines than in non-cohesive sand. The wider implications of these findings will be discussed. COHBED Project Team (NERC): Alan Davies (Bangor University); Daniel Parsons, Leiping Ye (University of Hull); Jeffrey Peakall (University of Leeds); Dougal Lichtman, Louise O'Boyle, Peter Thorne (NOC Liverpool); Sarah Bass, Andrew Manning, Robert Schindler (University of Plymouth); Rebecca Aspden, Emma Defew, Julie Hope, David Paterson (University of St Andrews)

Baas, Jaco H.; Baker, Megan; Hope, Julie; Malarkey, Jonathan; Rocha, Renata

2014-05-01

40

Upper Pleistocene turbidite sand beds and chaotic silt beds in the channelized, distal, outer-fan lobes of the Mississippi fan  

SciTech Connect

Cores from a Mississippi outer-fan depositional lobe demonstrate that sublobes at the distal edge contain a complex local network of channelized-turbidite beds of graded sand and debris-flow beds of chaotic silt. Off-lobe basin plains lack siliciclastic coarse-grained beds. The basin-plain mud facies exhibit low acoustic backscatter on SeaMARC IA sidescan sonar images, whereas high acoustic backscatter is characteristic of the lobe sand and silt facies. The depth of the first sand-silt layer correlates with relative backscatter intensity and stratigraphic age of the distal sublobes (i.e., shallowest sand = highest backscatter and youngest sublobe). The high proportion (> 50%) of chaotic silt compared to graded sand in the distal, outer-fan sublobes may be related to the unstable, muddy, canyon-wall source areas of the extensive Mississippi delta-fed basin slope. A predominance of chaotic silt in cores or outcrops from outer-fan lobes thus may predict similar settings for ancient fans.

Nelson, C.H.; Lee, H.L. (Geological Survey, Menlo Park, CA (United States)); Twichell, D.C.; Schwab, W.C. (Geological Survey, Woods Hole, MA (United States)); Kenyon, N.H. (Inst. of Oceanographic Sciences, Wormley, Surrey (United Kingdom))

1992-08-01

41

Comparing particle-size distributions in modern and ancient sand-bed rivers  

NASA Astrophysics Data System (ADS)

Particle-size distributions yield valuable insight into processes controlling sediment supply, transport, and deposition in sedimentary systems. This is especially true in ancient deposits, where effects of changing boundary conditions and autogenic processes may be detected from deposited sediment. In order to improve interpretations in ancient deposits and constrain uncertainty associated with new methods for paleomorphodynamic reconstructions in ancient fluvial systems, we compare particle-size distributions in three active sand-bed rivers in central Nebraska (USA) to grain-size distributions from ancient sandy fluvial deposits. Within the modern rivers studied, particle-size distributions of active-layer, suspended-load, and slackwater deposits show consistent relationships despite some morphological and sediment-supply differences between the rivers. In particular, there is substantial and consistent overlap between bed-material and suspended-load distributions, and the coarsest material found in slackwater deposits is comparable to the coarse fraction of suspended-sediment samples. Proxy bed-load and slackwater-deposit samples from the Kayenta Formation (Lower Jurassic, Utah/Colorado, USA) show overlap similar to that seen in the modern rivers, suggesting that these deposits may be sampled for paleomorphodynamic reconstructions, including paleoslope estimation. We also compare grain-size distributions of channel, floodplain, and proximal-overbank deposits in the Willwood (Paleocene/Eocene, Bighorn Basin, Wyoming, USA), Wasatch (Paleocene/Eocene, Piceance Creek Basin, Colorado, USA), and Ferris (Cretaceous/Paleocene, Hanna Basin, Wyoming, USA) formations. Grain-size characteristics in these deposits reflect how suspended- and bed-load sediment is distributed across the floodplain during channel avulsion events. In order to constrain uncertainty inherent in such estimates, we evaluate uncertainty associated with sample collection, preparation, analytical particle-size analysis, and statistical characterization in both modern and ancient settings. We consider potential error contributions and evaluate the degree to which this uncertainty might be significant in modern sediment-transport studies and ancient paleomorphodynamic reconstructions.

Hajek, E. A.; Lynds, R. M.; Huzurbazar, S. V.

2011-12-01

42

Co-pyrolysis of walnut shell and tar sand in a fixed-bed reactor.  

PubMed

This study investigated potential synergistic activities between tar sand and walnut shell during co-pyrolysis. A series of pyrolysis studies were conducted under specific operating conditions in a fixed-bed reactor. The highest yield of bio-oil from the co-pyrolysis was 31.84 wt.%, which represented an increase of 7.88 wt.% compared to the bio-oil yield from the pyrolysis of walnut shell alone. The bio-oils were characterized using various spectroscopic and chromatographic analysis techniques. The results indicated that the synergetic effect increased the co-pyrolysis bio-oil yield and its quality. Consequently, the results indicate that the bio-oils obtained will be suitable for the production of fuels and chemicals as feedstock after required improvements. PMID:21875795

Kar, Yakup

2011-10-01

43

Bedform development in mixed sand-mud: The contrasting role of cohesive forces in flow and bed  

NASA Astrophysics Data System (ADS)

The majority of subaqueous sediment on Earth consists of mixtures of cohesive clay and cohesionless sand and silt, but the role of cohesion on the development and stability of sedimentary bedforms is poorly understood. The results of new laboratory flume experiments on bedform development in cohesive, mixed sand-mud beds are compared with the results of previous experiments in which cohesive forces in high concentration clay flows dominated bedform development. Even though both series of mixed sand-mud experiments were conducted at similar flow velocities, the textural and structural properties of the bedforms were sufficiently different to permit the designation of key criteria for identifying bedform generation under cohesive flows against bedform generation on cohesive substrates. These criteria are essential for improving bedform size predictions in sediment transport modelling in modern sedimentary environments and for the reconstruction of depositional processes in the geological record. The current ripples developing on the cohesive, mixed sand-mud beds, with bed mud fractions of up to 18%, were significantly smaller than equivalent bedforms in noncohesive sand. Moreover, the bedform height showed a stronger inversely proportional relationship with initial bed mud fraction than the bedform wavelength. This is in contrast with the bedforms developing under the cohesive clay flows, which tend to increase in size with increasing suspended clay concentration until the flow turbulence is fully suppressed. Selective removal of clay from the mixed beds, i.e., clay winnowing, was found to be an important process, with 82-100% clay entrained into suspension after 2 h of bedform development. This winnowing process led to the development of a sand-rich armouring layer. This armouring layer is inferred to have protected the underlying mixed sand-mud from prolonged erosion, and in conjunction with strong cohesive forces in the bed may have caused the smaller size of the bedforms. Winnowing was less efficient for the bedforms developing under the cohesive clay flows, where bedforms consisting of muddy sand were more characteristic. The winnowed sand was also found to heal irregularly scoured topography, thus reestablishing classic quasitriangular bedform shapes. In cohesive flows, the bedforms had more variable shapes, and the healing process was confined to lower transitional plug flows in which strong turbulence is only present close to the sediment bed. Furthermore, the bedforms on the cohesive beds tended to form angle-of-repose cross lamination, whereas low angle cross lamination was more common in bedforms under cohesive flows. In general terms, erosional bedforms prevail when cohesive forces in the bed dominate bedform dynamics, whereas depositional bedforms prevail when cohesive forces in the flow dominate bedform dynamics. Empirical relationships between the proportion of cohesive mud in the mixed sand-mud bed and the development rate and size of the bedforms are defined for future use in field and laboratory studies.

Baas, Jaco H.; Davies, Alan G.; Malarkey, Jonathan

2013-01-01

44

Combination fluid bed dry distillation and coking process for oil\\/tar sands  

Microsoft Academic Search

A process and apparatus for direct coking of tar sands which includes contacting the tar sand with heat transfer particles resulting from combustion of coked sand effluent from the coking process, and transporting the combination up a riser\\/mixer to a coking vessel whereby separation of oil and hydrocarbon gases from the sand is initiated. The tar sand is introduced into

H. Owen; J. H. Haddad; J. C. Zahner

1985-01-01

45

Progress report number 2: investigations of some sedimentation characteristics of sand-bed streams  

USGS Publications Warehouse

Hydraulic and sediment characteristics at six river sections upstream and downstream from the confluence of the Middle Loup and Dismal Rivers were measured and studied to determine some of the interrelationships between variables and the differences that exist between common variables when two flows unite. The two streams, which flow through the Sandhills region of Nebraska, have about the same water discharge, sediment concentration, and particle-size distribution of suspended sediment and bed material. Sediment discharges and flow resistances varied widely, although water discharges remained almost constant. The factor affecting the variations was water temperature, which ranged from 32° to 80° F. The bed form, which also varied with the water temperature, seemed to have a dominating influence on the sediment discharge, flow resistance, and possibly the vertical distribution of velocity and suspended sediment. Multiple regression with parameters derived from dimensional analysis yielded an expression for predicting the flow resistance and the widths and depths of individual channel sections. Contrary to those near many other confluences, slopes were steeper and channels were wider downstream from the junction of the two rivers than they were upstream. An investigation of specific sediment-transport phenomena and field procedures was made during 1956 and 1957 in cooperation with the U.S. Bureau of Reclamation. The purposes of this investigation were to provide information on the regime of rivers and to improve the procedures related to the collection of sediment data. The basic data and results of the studies made in 1956 were presented in progress report number 1, "Investigations of Some Sedimentation Characteristics of a Sand-Bed Stream." Some of the basic data and results of the studies made in 1957 are given in this report.

Hubbell, D.W.

1960-01-01

46

Numerical Modeling of Bifurcation Evolution in a Sand-bed Braided River  

NASA Astrophysics Data System (ADS)

River bifurcations are key units in a braided river. Although simple bifurcations are well understood and can be analyzed by 1D models (e.g. Bolla Pittaluga et al., 2003 and Kleinhans et al., 2008), predicting the stability and dynamics of multiple interacting bifurcations in a braided river with migrating bars requires understanding of the interaction between braid bars, channel network and bifurcations, in particular the upstream curvature and downstream backwater effects. Our objective is to understand the evolution of bifurcations at migrating bars in a braided river and the effects on bar evolution. We used the 3D numerical morphodynamic model Delft3D to produce a dynamically braiding sand bed river. This model solves the 3D-flow and computes sediment transport and bed level change accounting for effects of transverse bed slope. It includes a simple bank erosion model to reactivate emerged areas. The morphology of mid-channel bars produced by the model was analyzed and the partitioning of water and sediment over the bifurcating channels are compared with a 1D model concept. Next, the evolution of bars is linked to that of the bifurcations, in order to infer relations between bar morphology and bifurcation evolution. We find that upstream bar dynamics have a major effect on the stability of bifurcations. Migration and elongation of bars can close the upstream entrance of a bifurcation channel, independent of the stability of the bifurcation. Moreover, bifurcation angle and upstream curvature can be affected by upstream bar migration and elongation, which steers flow and sediment partitioning at the bifurcation. At the same time, the partitioning of water and sediment over a bifurcation affects bar shape. Sediment eroded at one of the bar sides just downstream of the bifurcation deposits downstream of the braid bar in the form of tail bars. Hence bar shape as observable on imagery contains useful information about the evolution of the upstream bifurcation and may be used to predict the development of downstream bifurcations and bars.

De Haas, T.; Schuurman, F.; Kleinhans, M. G.

2012-12-01

47

New England Shellfish Beds Reopen After Toxic Red Algae Recedes  

NSDL National Science Digital Library

This PBS article describes red tide, a phenomenon caused by phytoplankton in coastal waters. The site includes brief summaries of the causes and impacts of red tide, both on health and the tourism industry. A link to a PDF version of the article is provided.

Schleicher, Annie; Extra, Public B.

48

The use of fluidized sand bed as an innovative technique for heat treating aluminum based castings  

NASA Astrophysics Data System (ADS)

The current study was carried out to arrive at a better understanding of the influences of the fluidized sand bed heat treatment on the tensile properties and quality indices of A356.2 and B319.2 casting alloys. For the purposes of validating the use of fluidized sand bed furnaces in industrial applications for heat treatment of 356 and 319 castings, the tensile properties and the quality indices of these alloys were correlated with the most common metallurgical parameters, such as strontium modification, grain refining, solutionizing time, aging parameters and quenching media. Traditional heat treatment technology, employing circulating air convection furnaces, was used to establish a relevant comparison with fluidized sand beds for the heat treatment of the alloys investigated, employing T6 continuous aging cycles or multi-temperature aging cycles. Quality charts were used to predict and/or select the best heat treatment conditions and techniques to be applied in industry in order to obtain the optimum properties required for particular engineering applications. The results revealed that the strength values achieved in T6-tempered 319 and 356 alloys are more responsive to fluidized bed (FB) heat treatment than to conventional convection furnace (CF) treatment for solution treatment times of up to 8 hours. Beyond this solution time, no noticeable difference in properties is observed with the two techniques. A significant increase in strength is observed in the FB heat-treated samples after short aging times of 0.5 and 1 hour, the trend continuing up to 5 hours. The 319 alloys show signs of overaging after 8 hours of aging using a conventional furnace, whereas with a fluidized bed, overaging occurs after 12 hours. Analysis of the tensile properties in terms of quality index charts showed that both modified and non-modified 319 and 356 alloys display the same, or better, quality, after only a 2-hr treatment in an FB compared to 10 hours when using a CF. The quality values of the 356 alloys are more responsive to the FB technique than 319 alloys through long aging times of up to 5 hours. The 319 alloys heat-treated in an FB, however, show better quality values after 0.5 hour of aging and for solution treatment times of up to 5 hours than those treated using a CF. With regard to the quality charts of 319 alloys, heat-treated samples show that increasing the aging time up to peak-strength, i.e. 8 and 12 hours in a CF and an FB, respectively, results in increasing in the alloy strength with a decrease in the quality values, for each of the solution heat treatment times used. The statistical analysis of the results reveals that modification and heating rate of the heat treatment technique have the greatest positive effects on the quality values of the 356 alloys. The use of a fluidized sand bed for the direct quenching-aging treatment of A356.2 and B319.2 casting alloys yields greater UTS and YS values compared to conventional furnace quenched alloys. The strength values of T6 tempered A356 and B319 alloys are greater when quenched in water compared to those quenched in an FB or CF. For the same aging conditions (170°C/4h), the fluidized bed quenched-aged 319 and 356 alloys show nearly the same or better strength values than those quenched in water and then aged in a CF or an FB. Based on the quality charts developed for alloys subjected to different quenching media, higher quality index values are obtained by water-quenched T6-tempered A356 alloys, and conventional furnace quenched-aged T6-tempered B319 alloys, respectively. The modification factor has the most significant effect on the quality results of the alloys investigated, for all heat treatment cycles, as compared to other metallurgical parameters. The results of alloys subjected to multi-temperature aging cycles reveal that the strength results obtained after the T6 continuous aging treatment of A356 alloys are not improved by means of multi-temperature aging cycles, indicating therefore that the optimum properties are obtained using a T6 aging treatment. The optimu

Ragab, Khaled

49

Lithofacies, microfacies and depositional environments of Upper Cretaceous Oceanic red beds (Chuangde Formation) in southern Tibet  

Microsoft Academic Search

The Gyangze basin, located in southern Tibet, is one of the representative areas for Cretaceous Oceanic Red Beds (CORBs). We investigated and inter-correlated several new CORB outcrops in the western and southeastern part of the Gyangze area in addition to the previously described Chuangde section. The CORBs in the Gyangze basin mainly consist of shales, thin-bedded marls, re-sedimented limestones and

Xi Chen; Chengshan Wang; Wolfgang Kuhnt; Ann Holbourn; Yongjian Huang; Chao Ma

2011-01-01

50

Natural occurrence of hexavalent chromium in the Aromas Red Sands Aquifer, California.  

PubMed

To address increasing concerns of chromium contamination in the drinking water of Santa Cruz County, we designed a study to investigate the source(s) and spatial gradients of the chromium concentration and speciation in local aquifers. This study was catalyzed by a report (January 2001) bythe Soquel Creek Water District of elevated hexavalent chromium concentrations ranging from 6 to 36 microg L(-1), approaching the state's maximum concentration limit of 50 microg L(-1), in the Aromas Red Sands aquifer. To test the accuracy of those preliminary measurements, we collected groundwater using trace metal clean techniques from 11 sites in Santa Cruz County, including 10 from the aquifer with reportedly elevated chromium concentrations and 1 from an adjacent aquifer, the Purisima, and analyzed them fortotal chromium using inductively couple plasma mass spectrometry. Nine of the reportedly 10 contaminated sites had total chromium concentrations ranging from 5 to 39 microg L(-1), while one from the control site was below the limit of detection (0.01 microg L(-1)). We also measured the speciation of chromium at all sites using a solid supported membrane extraction coupled with graphite furnace atomic absorption spectrometry and determined that on average 84% of total chromium was Cr(VI). In addition to the groundwater analyses, a series of extractions were performed on sediment samples from both the Aromas Red Sands and Purisima aquifers. These tests were used to empirically characterize sediment trace metal (Cr, Fe, Mn) distributions in five phases providing information about the origin, availability, reactivity, and mobilization of these trace metals. Results from groundwater and sediment samples indicate that the chromium is naturally occurring in the Aromas Red Sands aquifer, possibly by Cr(III) mineral deposits being oxidized to Cr(VI) by manganese oxides in the aquifer. PMID:16124280

Gonzalez, A R; Ndung'u, K; Flegal, A R

2005-08-01

51

[Ectoparasites. Part 2: Bed bugs, Demodex, sand fleas and cutaneous larva migrans].  

PubMed

Ectoparasites or epidermal parasites include a very heterogenous group of infections of the outer layers of the skin. Worldwide the most common are scabies, lice, tungiasis, and hookworm-induced cutaneous larva migrans. In recent years, bed bug infestations in hotels or vacation homes seem to have become more frequent. Demodex folliculorum and Demodex brevis are found in the facial and scalp hair follicles in 95% of individuals. Classic Demodex folliculitis is often overlooked in differential diagnostic considerations. This inflammatory sebaceous gland disease as well as Demodex blepharitis both provide a diagnostic and therapeutic challenge. Permethrin can be used topically against demodicosis. Vacationers who go barefoot on beaches in tropical Africa, South America and subtropical Asia risk infestations from female sand fleas. The lesions can be curetted or removed with a punch biopsy, then treated with antiseptics or even systemic antibiotics if a secondary infection develops. Cutaneous larva migrans is one of the most common imported ectoparasite infections from the tropics. Topical treatment measures include thiabendazole or cryotherapy. If the infestation is severe, systemic antihelminthics or ivermectin can be employed. PMID:19701614

Nenoff, P; Handrick, W; Krüger, C; Herrmann, J; Schmoranzer, B; Paasch, U

2009-09-01

52

Degradation of anionic surfactants during drying of UASBR sludges on sand drying beds.  

PubMed

Anionic surfactant (AS) concentrations in wet up-flow anaerobic sludge blanket reactor (UASBR) sludges from five sewage treatment plants (STPs) were found to range from 4480 to 9,233 mg kg(-1)dry wt. (average 7,347 mg kg(-1)dry wt.) over a period of 18 months. After drying on sand drying beds (SDBs), AS in dried-stabilized sludges averaged 1,452 mg kg(-1)dry wt., a reduction of around 80%. The kinetics of drying followed simple first-order reduction of moisture with value of drying constant (k(d))=0.051 d(-1). Reduction of AS also followed first-order kinetics. AS degradation rate constant (k(AS)) was found to be 0.034 d(-1) and half-life of AS as 20 days. The order of rates of removal observed was k(d)>k(AS)>k(COD)>k(OM) (drying >AS degradation>COD reduction>organic matter reduction). For the three applications of dried-stabilized sludges (soil, agricultural soil, grassland), values of risk quotient (RQ) were found to be <1, indicating no risk. PMID:17618731

Mungray, Arvind Kumar; Kumar, Pradeep

2008-09-01

53

The mobility and distribution of heavy metals during the formation of first cycle red beds.  

USGS Publications Warehouse

Analysis of the heavy metal content in a Holocene-Pliocene red bed sequence near San Felipe in N Baja California, Mexico, has yielded new information on the mobility and distribution of these metals during ageing of iron oxyhydroxides from the amorphous to the crystalline state. Whole-rock samples (27) and a series of successive leachates were analysed for V, Al, Cr, Mn, Fe, Co, Ni, Cu and Zn by ICP spectrometry and for U by a delayed neutron technique. These data are supported by a variety of other mineralogical and petrographical observations. The results indicate that the metal content of the samples is predominantly inherited from the constituent detrital minerals. Reddening of the whole-rock samples does not promote major open-system migration of the heavy metals; rather, contained metals redistribute themselves on an intergranular scale, moving from detrital mineral hosts to the secondary iron oxides. The amount of secondary iron oxides and the fraction of whole-rock metals associated with these oxides increase during red-bed development. In addition, the abundance of well- crystallized iron oxides increases during this period. Differences in the leaching efficiency for various metals are related to differences in metal site distribution and intergranular permeability. Inferred conditions for rapid vs limited removal of metals from red beds are summarized. It is suggested that developed red beds which are well flushed by suitable pore fluids may be sources of significant quantities of heavy metals. -J.E.S.

Zielinski, R.A.; Bloch, S.; Walker, T.R.

1983-01-01

54

Measurement and computation of bed-material discharge in a shallow sand-bed stream, Muddy Creek, Wyoming  

Microsoft Academic Search

Both the measurement and computation of the bed-material discharge of a stream involve large uncertainties because of the difficulties in determining bedload discharge. Measurements of bedload discharge are rare and frequently of unknown accuracy because no bedload sampler has been extensively tested and calibrated over a wide range of hydraulic conditions. Bed-material discharge equations have been derived primarily from laboratory

E. D. Andrews

1981-01-01

55

Chute Formation and Iterative Adjustment in Large, Sand-Bed Meandering Rivers  

NASA Astrophysics Data System (ADS)

The meandering-braided continuum is a planform manifestation of excess available river energy; a balance between the energy of flow (commonly quantified as unit steam power or shear stress), and dynamic resistance due to bed material calibre and bank strength. Single-thread meandering rivers plot in part of the continuum defined by low excess available river energy, while braided rivers plot in part of the continuum defined by high excess available river energy. Planform patterns that are transitional between single-thread meandering and braided occur where chute channel formation is prolific. In this presentation we will elucidate the morphodynamic implications of chute formation for sinuosity and planform pattern in large, sand-bed meandering rivers. We draw on the results of recent research that applied binary logistic regression analysis to determine the possibility of predicting chute initiation based on attributes of meander bend character and dynamics (Grenfell et al., accepted, ESP&L). Regression models developed for the Strickland River, Papua New Guinea (54 bends), the lower Paraguay River, Paraguay/Argentina (45 bends), and the Beni River, Bolivia (114 bends), revealed that the probability of chute initiation at a meander bend is a function of the bend extension rate (the rate at which a bend elongates). Image analyses of all rivers and field observations from the Strickland suggest that the majority of chute channels form during scroll-slough development. Rapid extension is shown to favour chute initiation by breaking the continuity of point bar deposition and vegetation encroachment at the inner bank, resulting in widely-spaced scrolls with intervening sloughs that are positively aligned with primary over-bar flow. The rivers plot in order of increasing chute activity on an empirical meandering-braided pattern continuum (Kleinhans and van den Berg, 2011, ESP&L 36) defined by potential specific stream power (?pv) and bedload calibre (D50). Increasing stream power is considered to result in higher bend extension rates, with implications for chute initiation, but we demonstrate that the probability of chute stability decreases with increasing sediment load (Qs/Q). We extend our empirical results with additional spatial analyses of chute initiation and infill on the Strickland, Paraguay, and Beni Rivers, and the Ok Tedi in Papua New Guinea, and explore the physical basis of chute stability with Delft 3D simulations, based on surveyed channel bathymetry from the Strickland. Results demonstrate that chute formation exerts negative feedback on bend extension (and channel sinuosity and slope) if the chute diverts sufficient flow from the mainstem, or leads to bend cutoff. This interplay between rapid extension, preferential chute initiation at rapidly extending bends, and subsequent feedback effects is framed within the theory of 'iterative adjustment' (Nanson and Huang, 2008, ESP&L 33), providing a conceptual framework for understanding self organisation in rivers subject to chute formation and chute cutoff. We suggest that this conceptual framework provides an alternative but allied theory to 'self-organised criticality', which has been used to explain the role of neck cutoff in some meandering rivers.

Grenfell, M. C.; Aalto, R. E.; Nicholas, A.

2011-12-01

56

Infra-red stimulated luminescence ages from aeolian sand and alluvial fan deposits from the eastern Mojave Desert, California  

NASA Astrophysics Data System (ADS)

Infra-red stimulated luminescence (IRSL) from coarse-grained (180-212 ?m) potassium-rich feldspars has been used to date deposits associated with the western piedmont of the Providence Mountains in the eastern Mojave Desert. These deposits consist of alluvial fans, aeolian sand, which exists in the form of lenses within the fan matrices, and sand from the Kelso dune field which abuts the distal end of the fan sequence. Deposition and subsequent stabilisation of these sand units appears to have occurred in both aird and intermittent climates associated with pluvial phases during the Holocene and Late Pleistocene. Ages of 6600 ± 870 and 7840 ± 1790 years were obtained from dune sand bracketing the Mazama ash at Skull Creek Dunes, Oregon, giving an independent age control on the single aliquot IRSL method which was used on the Mojave samples.

Clarke, M. L.

57

Drivers of bacterial diversity dynamics in permeable carbonate and silicate coral reef sands from the Red Sea  

PubMed Central

Permeable sediments and associated microbial communities play a fundamental role in nutrient recycling within coral reef ecosystems by ensuring high levels of primary production in oligotrophic environments. A previous study on organic matter degradation within biogenic carbonate and terrigenous silicate reef sands in the Red Sea suggested that observed sand-specific differences in microbial activity could be caused by variations in microbial biomass and diversity. Here, we tested this hypothesis by comparing bacterial abundance and community structure in both sand types, and by further exploring the structuring effects of time (season) and space (sediment depth, in/out-reef). Changes in bacterial community structure, as determined via automated ribosomal intergenic spacer analysis (ARISA), were primarily driven by sand mineralogy at specific seasons, sediment depths and reef locations. By coupling ARISA with 16S-ITS rRNA sequencing, we detected significant community shifts already at the bacterial class level, with Proteobacteria (Gamma-, Delta-, Alpha-) and Actinobacteria being prominent members of the highly diverse communities. Overall, our findings suggest that reef sand-associated bacterial communities vary substantially with sand type. Especially in synergy with environmental variation over time and space, mineralogical differences seem to play a central role in maintaining high levels of bacterial community heterogeneity. The local co-occurrence of carbonate and silicate sands may thus significantly increase the availability of microbial niches within a single coral reef ecosystem. PMID:21554515

Schottner, Sandra; Pfitzner, Barbara; Grunke, Stefanie; Rasheed, Mohammed; Wild, Christian; Ramette, Alban

2011-01-01

58

Cretaceous oceanic red beds (CORBs): Different time scales and models of origin  

NASA Astrophysics Data System (ADS)

The Cretaceous oceanic red bed (CORB) is a newly opened window on global oceanic and climate changes during the Cretaceous greenhouse world. As a result of the International Geoscience Programmes 463, 494 and 555 (2002-2010), CORBs have been documented in many places by numerous publications. The principle goal of this paper is to summarize scientific advances on CORBs including chronostratigraphy, sedimentology, mineralogy, elemental and isotopic geochemistry, and their relationship to oceanic anoxic events (OAEs), palaeoclimate and palaeoceanography. We propose a new geochemical classification of the CORBs using CaO, Al2O3 and SiO2 values, which lithologically refer to marly, clayey, and cherty CORBs respectively. Detailed mineralogical studies indicate that hematite, goethite and Mn2 +-bearing calcite are the minerals imparting the red color of CORBs. Hematite clusters of several to tens of nanometers in the calcite structure are the main cause of the red coloring of limestones, and the Mn2 +-bearing calcite gives additional red color. Goethite was thought to form originally with hematite, and was subsequently transformed to hematite during late diagenesis. Chronostratigraphic data allow the distinction of two groups of CORBs by their durations. Short-term CORBs are generally less than 1 myr in duration, and seem to be on the scale of Milankovitch cycles. During the deposition of Cretaceous reddish intervals from ODP cores 1049 and 1050, low primary productivity and relatively high surface temperature resulted in low organic carbon flux into the sediments which reduced oxygen demand and produced oxidizing early diagenetic conditions. In such an oxic environment, iron oxides formed imparting the reddish color. The long-term CORBs' depositional events lasted longer than 4 myr, and may be a possible consequence of the OAEs. Enhanced amounts of organic carbon and pyrite burial during and after the OAEs would have resulted in a large and abrupt fall in atmospheric CO2 concentration, which probably induced significant global climatic cooling during and after the OAEs. Global cooling would have enhanced formation of cold deep water, increasing its oxidizing capacity due to the greater content of dissolved oxygen and would promote formation of oceanic red beds. Sedimentological, mineralogical and geochemical data indicate that CORBs were deposited under highly oxic, oligotrophic conditions probably at a low sedimentation rate. The Cretaceous red and white limestones from Italy have similar compositions of terrestrial input-sensitive elements (Al, Ti, K, Mg, Rb, Zr), higher contents of Fe2O3, and depleted redox-sensitive elements (V, Cr, Ni, and U) and micronutrient elements Cu, Zn, indicating similar provenance sources but red limestones were deposited under more oxic conditions at the sediment-water interface than white limestones. The Cretaceous red shales such as those from the North Atlantic and Tibet have similar mineralogy and geochemistry as the Late Cenozoic red clays in the Pacific Ocean and the environment where both are formed was well-oxidizing at a very low sedimentation rate. We compiled seventeen published stratigraphic examples of Phanerozoic oceanic red beds including the Late Cenozoic red clays in the Pacific. Different hypotheses explain the origin of red pigmentation of limestones and shales including (1) detrital origin of iron derived from continental weathering; (2)iron-bacterial mediation at the time of sedimentation; and (3) iron oxidation in oligotrophic, highly oxic environment. Additional research on Phanerozoic oceanic red beds is needed in order to better document their origin and palaeoceanographic and palaeoclimatic significance.

Hu, Xiumian; Scott, Robert W.; Cai, Yuanfeng; Wang, Chengshan; Melinte-Dobrinescu, Mihaela C.

2012-12-01

59

Paleomagnetism of a lateritic paleoweathering horizon and overlying Paleoproterozoic red beds from South Africa: Implications for the  

E-print Network

South Africa: Implications for the Kaapvaal apparent polar wander path and a confirmation of atmospheric: paleomagnetism, Paleoproterozoic, South Africa, apparent polar wander paths, paleoatmosphere, lateritic paleosols Paleoproterozoic red beds from South Africa: Implicat

60

A paleomagnetic study of remagnetized Upper Jurassic red beds from Chihuahua, northern Mexico  

NASA Astrophysics Data System (ADS)

Paleomagnetic results from 75 samples (132 specimens) collected from 20 beds from a ˜55-m thick sequence of Upper Jurassic red beds from La Casita Formation, northern Mexico are reported. Detailed partial thermal (up to 680°C) and alternating field (up to 320 mT) demagnetizations reveal different behaviors of vectorial composition and magnetic stability. Before tilt correction, the directions cluster around the dipolar and present-day field directions for northern Mexico. The dominant well-grouped remanent magnetization directions after tilt correction are steeply dipping and lie far apart from Mesozoic-Cenozoic directions reported for northern Mexico and North America. The high-coercivity magnetization components apparently reside predominantly in red pigment hematite. Polished section observations show a more complex mineral assemblage, characterized by abundant red pigment and well-rounded opaque hematite, titanomagnetite and ilmenite grains. Titanomagnetites are less abundant and show a fresh angular appearance with low oxidation class (C-1 and C-2). Most samples are characterized by the high-coercivity present field magnetization directions, which are attributed to red hematite pigment recently magnetized. Some samples in contrast show two or more magnetization components. High-temperature magnetization components (i.e. those observed between 550-600°C and 680°) show reversed polarity. However, vector plots are noisy, and directional changes during demagnetization are often accompanied by increases in intensity and are not consistent between samples. Results of incremental partial thermal demagnetization on the low-field magnetic susceptibility anisotropy have been studied by heating samples to successively higher temperatures and measuring the anisotropy after cooling in air from each temperature increment. The results conform to the pattern generally expected for a primary depositional fabric with predominantly oblate-shaped susceptibilities, and with k3 directions close to the bedding pole and k1 directions lying in the bedding plane and preferentially aligned in a SW-NE directions as a result of possible currents acting at the time of deposition. The available evidence indicates that these red beds have been remagnetized and that most of the magnetization was acquired during recent (Brunhes Chron) times.

Herrero-Bervera, Emilio; Urrutia-Fucugauchi, Jaime; Khan, M. A.

61

Shallowed vs. Concordant Paleomagnetic Inclinations in Asian red Beds: Tectonic Implications  

NASA Astrophysics Data System (ADS)

Anomalously low paleomagnetic inclinations are often recorded in Asian red beds. Based on the available age control, most Tertiary sections show low inclinations while inclinations concordant with the paleomagnetic pole of Eurasia are generally recorded in Cretaceous red beds. This inclination pattern hinders tectonic interpretations but may also yield important constraints on the development of the Indo-Asia collisional system. To better constrain the reliability of the paleomagnetic record, we investigate the rock magnetic and petrologic signature in samples from 21 stratigraphic sections collected north of the Tibetan plateau. In addition to classic thermal demagnetization of NRM, IRM acquisition curves in fields up to 8 T were used to characterize magnetic mineralogy. Magnetite and hematite bearing samples can both be affected by inclination shallowing. AMS reveals a characteristic sedimentary fabric regardless of the degree of inclination shallowing. Separation of the paramagnetic from the ferromagnetic contribution of the anisotropy is performed according to Hernandez and Hirt (2001) technique. In samples with shallowed inclination, the anisotropy of the ferromagnetic fraction mimics the sedimentary fabric of the paramagnetic fraction. Determination of AAR using both the thermal themagnetization of Tan et al. (2002) protocol as well as a high-field IRM protocol involving IRM acquisition in 13 Tesla fields to erase the magnetic history of previous steps (Kodama and Dekkers, submitted) was carried out on representative samples with shallowed and with concordant inclinations. We hope that the distinct properties of the analyzed sediments will provide us with tools to discriminate red beds affected by inclination shallowing from sediments recording the correct paleomagnetic inclination from which paleopole positions can be confidently calculated

Dupont-Nivet, G.; Martin-Hernandez, F.; Dekkers, M. J.; Kodama, K.

2003-12-01

62

Granulation of Fe–Al–Ce nano-adsorbent for fluoride removal from drinking water by spray coating on sand in a fluidized bed  

Microsoft Academic Search

A technology for the granulation of Fe–Al–Ce nano-adsorbent (Fe–Al–Ce) in a fluidized bed was developed. The coating reagent, a mixture of Fe–Al–Ce and a polymer latex, was sprayed onto sand in a fluidized bed. The granule morphology, coating layer thickness, granule stability in water and adsorption capacity for fluoride was investigated by analyzing samples for different coating time. The coating

Lin Chen; Hai-Xia Wu; Ting-Jie Wang; Yong Jin; Yu Zhang; Xiao-Min Dou

2009-01-01

63

A simplified Red Bed Inclination Correction: Case Study from the Permian Esterel Group of France.  

NASA Astrophysics Data System (ADS)

Magnetic anisotropy-based inclinations corrections have been performed in the paleomagnetic laboratory at Lehigh University, on both hematite and magnetite-bearing sedimentary rocks. Results of these corrections indicate a latitudinal variation of inclination shallowing with the formations initially located at mid latitudes suffering from more shallowing than those initially closer to the equator, consistent with the tan (Im)= f * tan (If) relationship observed by King (1955) for inclination shallowing, where Im is the measured inclination and If is the field inclination during deposition. Shallowing of the paleomagnetic vectors can be expressed in terms of the flattening factor f, that relates tan (Im) to tan (If). Anisotropy- derived hematite f factors from the Maritime Provinces of Canada and Northwest China were combined with f factors derived from corrections that use models of geomagnetic field secular variation (the EI technique of Tauxe and Kent, 2004) on red bed Formations from North America, Greenland and Europe. The dataset was used to derive a probability density function for f. The mean f value will allow a simplified inclination correction for hematite-bearing red bed formations that are suspected to be affected by inclination shallowing. This approach was tested by correcting the Permian Esterel Group red beds from France: using the distribution mean f factor of 0.64 (±0.11, ±1 standard deviation), the corrected red bed paleopole becomes statistically indistinguishable from the paleopole measured for the Esterel Group volcanic rocks that have not suffered from inclination shallowing. f data was also compiled for magnetite-bearing sedimentary rocks from the Perforada Formation and the Valle Group from Baja California, Mexico, the Pigeon Point Formation of Central California, the Ladd and the Point Loma Formations from Southern California, the Nanaimo Group of British Columbia and the Deer Lake Group of Newfoundland that have been corrected for inclination shallowing, yielding a most probable f factor of 0.67 (±0.06). Based on our results, the maximum amounts of shallowing that can be expected for sedimentary rocks is 12.4° for hematite-bearing rocks, and 11.8° for magnetite-bearing rocks. These values are statistically indistinguishable. Therefore, we combined the datasets and have obtained an f factor of 0.66 (±0.1) that can be used for either hematite or magnetite-bearing sedimentary rocks. A major implication of this result is that a rock's NRM, either acquired by chemical processes soon after deposition or by depositional processes that accurately record the ambient magnetic field, may be susceptible to similar amounts of inclination shallowing, most likely caused by burial compaction.

Bilardello, D.; Kodama, K. P.

2008-12-01

64

Paleomagnetism of Devonian Red Beds in the Appalachian Plateau and Valley and Ridge Provinces  

NASA Astrophysics Data System (ADS)

Samples of fluvial to marine sandstones of the Chemung and Hampshire formations were analyzed from regional-scale and roadcut-scale folds across the structural trend of the Valley and Ridge (VR) and Appalachian Plateau (AP) provinces of northeast Virginia, western Maryland, and northeast West Virginia. Alternating field demagnetization only removes a modern VRM. After removal of a modern VRM, thermal demagnetization of most specimens reveals a characteristic remanent magnetization (ChRM) with southerly declinations and shallow inclinations between 350-600oC. Rock magnetic studies indicate this component resides in hematite. An additional hematite component is removed at temperatures greater than 600oC in a few specimens but is obscured by erratic decay and/or creation of new magnetic phases. Specimens without the ChRM generally have weak NRMs, lack red pigment, only contain the modern VRM, and are dominated by magnetite based on rock magnetic studies. Incremental fold tests for the ChRM yield generally prefolding results from the AP and synfolding results from the VR. The pole positions at the 95% confidence level overlap the late Carboniferous to middle Permian part of the APWP. Low burial temperatures indicate that the ChRMs are chemical remanent magnetizations (CRMs). Thin section analysis shows the presence of detrital magnetite with oxidation rims, authigenic specularite (some within quartz overgrowths), and a submicron size red pigment. Geochemical/fluid inclusion studies indicate that mixed orogenic/meteoric fluids altered the VR red beds; the CRM in the VR could be related to such fluids. In the AP, there is no evidence that the red beds have been altered by orogenic fluids and another chemical mechanism is needed to explain the remagnetization.

Cox, E.; Elmore, R. D.; Evans, M.

2003-12-01

65

Effect of Sand Supply on Transport Rates in a Gravel-Bed Channel  

E-print Network

, the sediment supplied is finer than that found in the river bed. Flushing of reservoir sediment and the removal of an increase in fine sediment supply on river morphology and ecology is necessary to evaluate dam removal and reservoir flushing plans and to assess the impacts of other possible sources of fine sediment supply

Curran, Joanna C.

66

Paleomagnetism of some Precambrian basaltic flows and red beds, Eastern Grand Canyon, Arizona  

USGS Publications Warehouse

Lava flows and red sandstone beds near the middle of the Upper Precambrian Grand Canyon Series exhibit stable remanent magnetization. The beds are about 1000 m stratigraphically above rocks of the Grand Canyon Series for which paleomagnetic poles have been reported. All specimens were subjected to stepwise thermal (200??-700??C) or alternating field (25-5000 Oe) demagnetization for the determination of characteristic magnetization. The pole for two flows and an intercalated sandstone bed of the Cardenas Lavas of Ford, Breed and Mitchell (upper Unkar Group), is at 174.6W, 0.4N (N = 10, K = 50, ??95 = 6.9??). The pole for a weathered zone developed across the Cardenas Lavas is at 167.8W, 49.4N (N = 5, K = 79, ??95 = 8.6??). The pole for directly overlying sandstone of the Nankoweap Formation of Maxson is at 174.4E, 12.5N (N = 6, K = 105, ??95 = 6.6??). These poles lie on or near, and appear to follow, part of an apparent polar wandering path recently proposed for the Precambrian of North America by Spall. If the fit is not accidental, little or no rotation has occurred between north-central Arizona and parts of the North American continent used to define the proposed path. ?? 1973.

Elston, D.P.; Robert, Scott G.

1973-01-01

67

Near-bed turbulence and relict waveformed sand ripples: Observations from the inner shelf  

Microsoft Academic Search

structure function within the inertial subrange, and ranged from 0.1 ? 10? 6 to 3 ? 10? 6 W\\/kg. The friction velocity, u*, at the bed ranged from 0.3 to 0.5 cm\\/s, and the wave friction factor, fw, from 0.017 to 0.02. The nearbed turbulence intensities and consequently the estimated values of u2* and fw are likely too small by

Alex E. Hay

2008-01-01

68

Paleomagnetism of Devonian red beds in the Appalachian Plateau and Valley and Ridge provinces  

NASA Astrophysics Data System (ADS)

Samples of red and green fluvial to marine sandstones in the Hampshire Formation/Catskill Group from regional-scale folds across the structural trend of the Valley and Ridge (VR) and Appalachian Plateau (AP) provinces of West Virginia were analyzed to test models for remagnetization of red sandstones. The red sandstones contain a dominant secondary Pennsylvanian-Permian magnetization with south declinations (154.8°-166.9°) and shallow inclinations (0.2°-19.3°) that resides in hematite and is interpreted as a chemical remanent magnetization (CRM) acquired during the Kiaman reversed superchron. Incremental fold tests for this CRM yield generally prefolding results from the AP rocks and synfolding results from the VR rocks. This suggests that the remanence acquisition in the AP may have occurred within the time span of deformation. A second, high unblocking temperature apparent synfolding CRM is also found in a few samples of the red sandstones and is distinguished by slightly steeper inclinations than the dominant component on northwest dipping beds. Specimens from green sandstone have weak intensities and are dominated by a modern viscous remanence. Thin section analysis shows the presence of authigenic specular hematite cement and submicron particle size red hematite pigment. Geochemical/fluid inclusion studies indicate that the rocks were exposed to mixed methane-saturated formational and meteoric fluids with no evidence that external warm orogenic fluids altered the rocks. A working model for CRM acquisition involves (1) methane reduction of previously formed iron phases and mobilization of iron and (2) a return to oxidizing conditions and precipitation of new authigenic hematite as a result of the introduction of meteoric fluids just prior to and during uplift. The green sandstones probably formed as a result of gleying which occurs in paleosols although they could be a relic of or preserve evidence of the reduction phase.

Cox, Eric; Elmore, R. Douglas; Evans, Mark

2005-08-01

69

Paleomagnetism and Magnetic Anisotropy of Neogene Red Beds from Tarim Basin, NW China  

NASA Astrophysics Data System (ADS)

Greater than 1000 km of continental shortening north of the Tarim basin has been derived from Cretaceous and Tertiary paleomagnetic data. Recent studies have shown that much of the continental shortening derived from Cretaceous results can be due to inclination error caused by deposition and compaction processes. To better understand the Tertiary paleomagnetic data from the Tarim basin, we conducted a combined paleomagnetic and magnetic anisotropy study for the Neogene red beds from the south Tianshan frontal thrust belt, north Tarim basin. A total of 11 sites of paleomagnetic cores were collected from the Neogene Kangcun Formation, and 81 samples were treated with progressive thermal demagnetization. A characteristic remanent magnetization (ChRM) was isolated at temperatures between 300 and 690°C from 9 sites. The mean ChRM direction, Dg =180.3°, Ig = -55.9°, kg = 5.5, ?95 =22.6°, in situ, and Ds = 177.7°, Is = -38.5°, ks = 15.5, ?95 = 14.4°, in stratigraphic coordinates, passes the McFadden (1990) fold test at 99% confidence level. Compared with the reference pole of Besse and Courtillot (2002), this direction implies about 23° of inclination shallowing. Anisotropy of magnetic susceptibility (AMS) reveals a triaxial, oblate fabric with foliation between 1.03 and 1.16, and minimum axis perpendicular to bedding. Each of the three axes of anisotropy ellipsoid passes the fold tests, indicating depositional and/or compaction fabrics. Measurement of high temperature component of isothermal remanent magnetization acquired in the bedding parallel and bedding perpendicular directions yielded anisotropy between 1.00 and 1.18. The remanent anisotropy shows a good relationship with paleomagnetic inclination. Linear and exponential fits yielded corrected inclinations of 56° and 57°, respectively, about 18° of inclination correction. The remaining inclination difference, 5°, can be explained by crustal shortening in Tianshan ranges.

Tan, X.; Kodama, K. P.; Chen, H.; Fang, D.; Sun, D.; Li, Y.

2009-12-01

70

The Cyborg Astrobiologist: Scouting Red Beds for Uncommon Features with Geological Significance  

E-print Network

The `Cyborg Astrobiologist' (CA) has undergone a second geological field trial, at a red sandstone site in northern Guadalajara, Spain, near Riba de Santiuste. The Cyborg Astrobiologist is a wearable computer and video camera system that has demonstrated a capability to find uncommon interest points in geological imagery in real-time in the field. The first (of three) geological structures that we studied was an outcrop of nearly homogeneous sandstone, which exhibits oxidized-iron impurities in red and and an absence of these iron impurities in white. The white areas in these ``red beds'' have turned white because the iron has been removed by chemical reduction, perhaps by a biological agent. The computer vision system found in one instance several (iron-free) white spots to be uncommon and therefore interesting, as well as several small and dark nodules. The second geological structure contained white, textured mineral deposits on the surface of the sandstone, which were found by the CA to be interesting. The third geological structure was a 50 cm thick paleosol layer, with fossilized root structures of some plants, which were found by the CA to be interesting. A quasi-blind comparison of the Cyborg Astrobiologist's interest points for these images with the interest points determined afterwards by a human geologist shows that the Cyborg Astrobiologist concurred with the human geologist 68% of the time (true positive rate), with a 32% false positive rate and a 32% false negative rate. (abstract has been abridged).

Patrick C. McGuire; Enrique Diaz-Martinez; Jens Ormo; Javier Gomez-Elvira; Jose A. Rodriguez-Manfredi; Eduardo Sebastian-Martinez; Helge Ritter; Robert Haschke; Markus Oesker; Joerg Ontrup

2005-05-23

71

Detection and Population Estimation for Small-Bodied Fishes in a Sand-Bed River  

Microsoft Academic Search

Multiple-pass removal by use of small-mesh seines within enclosed areas was performed to estimate numbers of nine small-bodied fish species at 17 sites in the Pecos River, New Mexico, during October 2007. Site-level population estimates were most precise for age-0 red shiners Cyprinella lutrensis (coefficient of variation [CV, calculated as SE\\/mean] = 0.02–0.06) and least precise for age-1 and older

Ann M. Widmer; Laura L. Burckhardt; Jon W. Kehmeier; Eric J. Gonzales; C. Nicolas Medley; Richard A. Valdez

2010-01-01

72

Upper Cretaceous oceanic red beds in southern Tibet: a major change from anoxic to oxic, deep-sea environments  

Microsoft Academic Search

Red marine mudstones intercalated with pelagic marlstones, limestones and radiolarian cherts comprise the Chuangde Formation, which overlies mid-Cretaceous dark grey shales in the northern subzone of the Himalayan Tethys of southern Tibet. The red mudstones reflect deposition below the carbonate compensation depth (CCD) in a deep oceanic basin. The intercalated, thin-bedded marlstones represent fine-grained turbidites derived from the upper slope

Chengshan Wang; Xiumian Hu; Massimo Sarti; Robert W. Scott; Xianghui Li

2005-01-01

73

Volcanic red-bed copper mineralisation related to submarine basalt alteration, Mont Alexandre, Quebec Appalachians, Canada  

NASA Astrophysics Data System (ADS)

Two types of native copper occur in Upper Silurian basaltic rocks in the Mont Alexandre area, Quebec Appalachians: (1) type 1 forms micrometric inclusions in plagioclase and is possibly magmatic in origin, whereas (2) type 2 occurs as coarse-grained patches rimmed by cuprite in altered porphyritic basalt. Type 1 has higher contents of sulphur (2,000-20,263 ppm) and arsenic (146-6,017 ppm), and a broader range of silver abundances (<65-2,186 ppm Ag) than type 2 (149-1,288 ppm S, <90-146 As, <65-928 ppm Ag). No mineral inclusions of sulphide or arsenide in native copper were observed at the electron-microprobe scale. Primary igneous fabrics are preserved, but the basaltic flows are pervasively oxidised and plagioclase is albitised. Chlorite replaces plagioclase and forms interstitial aggregates in the groundmass and has Fe/(Fe+Mg) ratios ranging from 0.29 to 0.36 with calculated temperatures between 155°C and 182°C. Copper sulphides in vacuoles and veinlets are associated with malachite, fibro-radiating albite and yarrowite (Cu9S8 with up to 0.3 wt% Ag). Bulk-rock concentrations of thallium and lithium range from 70 to 310 ppb and 10 to 22 ppm, respectively, and thallium is positively correlated with Fe2O3. Such concentrations of thallium and lithium are typical of spilitisation during heated seawater-basalt interaction. Spilitisation is consistent with the regional geological setting of deepwater-facies sedimentation, but is different from current models for volcanic red-bed copper, which indicate subaerial oxidation of volcanic flows. The volcanic red-bed copper model should be re-examined to account for native copper mineralisation in basalts altered by warm seawater.

Cabral, Alexandre Raphael; Beaudoin, Georges

2007-11-01

74

AMS Fabric of a CRM in Hematite-Bearing Samples: Evidence of DRMs in Natural Red Beds  

NASA Astrophysics Data System (ADS)

Anisotropy of magnetic susceptibility (AMS) and anisotropy of isothermal remanence (AIR) in red sedimentary rocks both typically show a bedding parallel foliation with minimum axes clustered perpendicular to the bedding plane. Our studies have observed this type of magnetic fabric in red bed units that have a range of ages and come from widespread localities. These units include the Mississippian Mauch Chunk Formation from the Appalachians, the Triassic Passaic Formation from the Newark basin in Pennsylvania, the Cretaceous Kapusaliang Formation from the Tarim basin in China, and the early Mesozoic Kayenta and Chinle Formations from the Colorado Plateau in southwestern North America. Bedding parallel foliations are also observed in magnetite-bearing rocks that carry a depositional remanence (DRM), suggesting the possibility of a DRM in red beds, even though the conventional wisdom is that they carry a post-depositional chemical remanent magnetization (CRM). Before the typical magnetic fabric of red beds can be used to indicate their type of remanence, we must determine what the magnetic fabric of a CRM looks like. For this reason, I conducted a series of hematite-growth experiments following the procedures outlined by Stokking and Tauxe (1987). I grew hematite in the laboratory on stacks of glass-fiber filter papers and in slurries of quartz and kaolinite. The hematite was grown from a ferric nitrate solution heated to 95° C for 8 hours. The samples were then dehydrated in a vacuum at room temperature for approximately 38 hours. It was possible to thermally demagnetize the eight filter paper samples to 350° C, but the six kaolinite-quartz samples were grown in plastic sample cubes and could only be thermally demagnetized to 150° C, enough to remove the thermoviscous magnetization acquired by the samples during the heating at 95° C. The mean CRM acquired by the red-brown magnetic phase grown in the experiments was within its alpha-95 of the steeply inclined (inclination=60°) ambient magnetic field. The kaolinite-quartz samples had a very scattered remanence, probably due to the physical disturbance of the samples upon the initial application of the vacuum. In both the filter paper and kaolinite-quartz experiments the AMS fabric of the CRM-carrying grains was foliated with the maximum and intermediate principal axes defining a great circle that passes through the mean CRM direction and is moderately inclined (approximately 45°) to the horizontal. The moderately inclined great circle defined by the maximum-intermediate principal axes is quite distinct from the horizontal maximum-intermediate axes observed in the natural red bed samples, despite red bed characteristic remanences that range from nearly horizontal (Passaic, Chinle, Kayenta) to as steep as 30° (Mauch Chunk, Kapusaliang). This observation suggests that red bed characteristic remanence is typically a DRM, rather than a CRM. This has implications for interpreting red bed remanence since DRMs in hematite-bearing red beds may have large inclination errors.

Kodama, K. P.

2002-12-01

75

Secular variation in Permian red beds from Dome de Barrot, Pauline P. Kruiver *, Mark J. Dekkers, Cor G. Langereis  

E-print Network

Secular variation in Permian red beds from Doªme de Barrot, SE France Pauline P. Kruiver *, Mark J . The variation in NRM directions is similar to present-day secular variation (SV). This suggests that SV: paleomagnetism; Milankovitch theory; hematite; depositional remanent magnetisation; secular variations; Permian 1

Utrecht, Universiteit

76

Cretaceous oceanic red beds as possible consequence of oceanic anoxic events  

NASA Astrophysics Data System (ADS)

Oceanic Anoxic Events (OAEs) represent brief periods of burial of large amounts of organic carbon in the oceans during Cretaceous time. Burial of organic carbon, which preferentially sequestered isotopically lighter carbon during OAEs, resulted in positive ? 13C excursions of 2-3‰ recognizable in global ocean. These deposits are typically dark-grey to black shales, considered to be the result of interaction between extreme warm climate, ocean circulation, high bioproductivity and organic carbon preservation. Less interest has been given to periods between OAEs, when oxic deep sea deposits such as red marls and red shales were deposited during mid- and Late Cretaceous. The latter deposits are associated with very low content of organic carbon and oxic depositional environments which dominated western Tethys in post Turonian time, up to the early Eocene. Feedbacks among geochemical cycles in response to decreasing global temperatures, increasing deep ocean circulation forced by high-latitude deep water formation along the Antarctic margin, and widening and deepening of the interconnections between the oceanic basins may have been responsible for the major paleoceanographic change from deposition of organic carbon-rich black shales during mid-Cretaceous, to world-wide deposition of Cretaceous Oceanic Red Beds (CORBs) in the Late Cretaceous. The presence of CORBs sandwiched between mid-Cretaceous OAEs may reflect major climate and paleoceanographic changes. In a contrast to extremely warm climates during the OAEs, the CORBs suggest cold periods, and therefore oscillating climate shifts, that have seldom been considered during modeling of Cretaceous greenhouse climate and global carbon cycling.

Wang, Chengshan; Hu, Xiumian; Huang, Yongjian; Wagreich, Michael; Scott, Robert; Hay, William

2011-03-01

77

Hydrology and bedload transport relationships for sand-bed streams in the Ngarradj Creek catchment, northern Australia  

NASA Astrophysics Data System (ADS)

SummaryRainfall, discharge and bedload were measured at three gauging stations (East Tributary, Upper Swift Creek and Swift Creek) in the Ngarradj Creek catchment at Jabiluka, Northern Territory, Australia. Hand-held, pressure difference, Helley-Smith bedload samplers were used to measure bedload fluxes for the 1998/1999, 1999/2000, 2000/2001 and 2001/2002 wet seasons. Rainfall is strongly seasonal over the Ngarradj Creek catchment, being concentrated in the wet season between November and April. Mean annual point rainfall between 1998 and 2007 for the water year, September to August, inclusive varied over the Ngarradj Creek catchment from 1731 ± 98 mm (SE) to 1754 ± 116 mm. Between 190 and 440 mm of rainfall are required before streamflow commences in December in most years. Streamflow persists until at least April. Mean annual runoff, as a percentage of mean annual rainfall, decreases slightly with increasing catchment area. Bedload ratings were calculated for four data sets. Significant bedload ratings were defined as those that were not only statistically significant (? ? 0.05) but also explained at least 0.60 of the variance in bedload flux. For the three stations, twenty-three bedload ratings complied with the above criteria. Sixteen equations were accepted for East Tributary, four bedload ratings were accepted for Upper Swift Creek and three bedload ratings were accepted for Swift Creek. Significant bedload ratings were established between bedload flux and discharge, unit bedload flux and discharge, transport rate of unsuspended bedload by immersed weight per unit width and time and both unit and excess unit stream power, and finally, adjusted submersed bedload weight and both unit and excess unit stream power for raw and log10-transformed data. 'Censored data sets' were compiled for Upper Swift Creek and Swift Creek to include only bedload fluxes measured when there was no apparent scour or fill so that there were no changes in sand supply from the catchment (i.e. equilibrium conditions). Bedload sediments are similar at all sites. There is little difference in grain size statistics between wet season bedload and dry season bed material. The differences which were significant suggest that most of the bed material is transported as bedload during the wet season. Size selective transport occurs at all three gauging stations with bedload being better sorted than bed material and the coarsest fraction (Cobble gravel) is mobile only during extreme events.

Erskine, W. D.; Saynor, M. J.

2013-03-01

78

Rock magnetic evidence for inclination shallowing in the early Carboniferous Deer Lake Group red beds of western Newfoundland  

NASA Astrophysics Data System (ADS)

A paleomagnetic and rock magnetic study of the Carboniferous Deer Lake Group red beds of Newfoundland was performed to detect and correct for inclination shallowing. Results indicate a primary remanence carried by magnetite, with a mean direction of D = 179.7°, I = 33.7°, ?95 = 7.2° which corresponds to a paleopole position of 22.2°N, 122.3°E, A95 = 7.6°. Correcting the inclination using anisotropy of anhysteretic remanence and the measured individual particle anisotropy gives a corrected direction of D = 178.8°, I = 50.9°, ?95 = 6.3° corresponding to a paleopole position at 8.4°N, 122.7°E, A95 = 7.2°. This correction is larger than that of other red beds from the Maritime Provinces of Canada, but is consistent with paleoenvironmental reconstructions, placing North America in a more arid climate zone. Our inclination-corrected results have important implications for this portion of North America's apparent polar wander path and suggest a correction is needed for other red bed-derived APWPs. We have determined the range of flattening factors f, defined as the proportionality constant between the tangents of the measured (Im) and field (Io) inclinations, tan(Im) = ftan(I0), from this study and previous inclination correction studies to estimate inclination corrections. Using the range of haematite f factors observed in this study to correct the Neogene red bed inclinations from the Vallès-Penedès Basin (NE Spain) yields inclinations consistent with the known geomagnetic field inclination in the Neogene, thus indicating that the range of f factors reported here may be used to estimate the magnitude of inclination shallowing in red beds.

Bilardello, Dario; Kodama, Kenneth P.

2010-04-01

79

The effects of repeated cycles of calcination and carbonation on a variety of different limestones, as measured in a hot fluidized bed of sand  

Microsoft Academic Search

The capacity of calcined limestone to react repeatedly with COâ, according to CaO{sub cr} + CO{sub 2(g)} = CaCO{sub 3(cr)} (eq I), and also its regeneration in the reverse reaction have been studied in a small, electrically heated fluidized bed of sand, for five different limestones. The forward step of eq I is a promising way of removing COâ from

Paul S. Fennell; Roberta Pacciani; John S. Dennis; John F. Davidson; Allan N. Hayhurst

2007-01-01

80

Hydraulic and topographic response of sand-bed rivers to woody riparian seedlings: field-scale laboratory methods and results  

NASA Astrophysics Data System (ADS)

Feedbacks between topography, flow fields and vegetation community structure are fundamental processes in many rivers. In addition, predicting seedling mortality in response to flood events requires a detailed understanding of the influence of flow on seedling scour and burial. As of yet, however, flow and sediment transport in the presence of seedlings are poorly understood. Measurements quantifying the response of topography and flow to the presence of seedlings with differing plant architectures were obtained within a field-scale meandering stream channel with a mobile sand bed (median grain size of 0.7 mm) and full experimental control over sediment and water discharge. Seedlings of Tamarix spp. (tamarisk) and Populus fremontii (cottonwood) with intact roots were installed on a point bar during low flow conditions. Flow rate was then elevated to a constant flood level, while sediment feed rate, plant density, and plant species were varied during each of eight different experimental runs. Flood conditions were maintained long enough for bar topography to reach steady state. The presence of all types of vegetation on the bar decreased the height and lateral extent of dunes migrating across the bar, thereby preventing the development of dunes as the primary mechanism of sediment transport through the bend. Time-averaged bar volume increased from bare-bed conditions when sparse tamarisk, dense tamarisk, or mixed cottonwood and tamarisk seedlings were present on the bar. The presence of dense cottonwood seedlings, however, did not result in an increase in either bar size or height, likely because an increase in steady-state turbulence intensities on the bar when dense cottonwood was present interfered with sediment deposition. Thus, differing plant architecture was an important influence on topographic evolution. In particular, it is possible that the flexibility of tamarisk seedlings causes them to behave analogously to herbaceous vegetation, sheltering the bar surface from turbulent eddies and encouraging deposition. Relationships for the influence of vegetation density and architecture on shear stress and sediment transport are suitable for incorporation into 2-D hydraulic and sediment transport models.

Lightbody, A.; Skorko, K.; Kui, L.; Stella, J. C.; Wilcox, A. C.

2012-12-01

81

From BIF to red beds: Sedimentology and sequence stratigraphy of the Paleoproterozoic Koegas Subgroup (South Africa)  

NASA Astrophysics Data System (ADS)

The ~ 2.4 Ga old Koegas Subgroup of the Transvaal Supergroup contains siliciclastics and iron formations. It occupies a transitional stratigraphic position between the major iron formations on the Kaapvaal craton, and strata with evidence for oxygenation of the environment. Koegas siliciclastics reflect a new phase of uplift and erosion on the craton after a period of chemical deposition. Paleocurrent data indicate transport to the west and northwest, away from the craton; however, no precise source area can as yet be defined. Rocks were deposited in foreshore to offshore environments of a prograding delta or submarine fan system. Immature arkosic wackes and subarkoses occur in proximal parts and pass to terrigenous mudstones and chemical iron formations in offshore environments with low detrital input. Lateral facies transitions and the hierarchical stratigraphic stacking pattern of the Koegas Subgroup allow a sequence stratigraphic interpretation in which regressive coarse siliciclastics prograded repeatedly over transgressive units of chemical iron formations. Metals in the transgressive units have an intrabasinal (hydrothermal) source, similar to underlying iron formations. Localized iron-stained detrital units resemble red beds. They reflect additional diagenetic Fe remobilization from deeper-water iron formations, or possibly a continental Fe source. The second possibility would imply the presence of some free oxygen in the environment.

Schröder, S.; Bedorf, D.; Beukes, N. J.; Gutzmer, J.

2011-05-01

82

Paleomagnetism of Cretaceous red beds from Tadzhikistan and Cenozoic deformation due to India-Eurasia collision  

NASA Astrophysics Data System (ADS)

We have carried out structural and paleomagnetic studies in the Tadzhik depression in order to evaluate the main features of the Alpine tectonics of this area. About 340 cores from 43 sites of Lower Cretaceous red beds were sampled from four different localities in the basin and adjacent ranges. A well-defined component of magnetization (A) of normal polarity with high unblocking temperatures up to 650-670 C was isolated from all the sites. Another component of magnetization (B) with unblocking temperatures between 650 and 680 C was isolated from only fifteen sites; this component is bipolar. The fold test is positive for both components. We believe that component A was acquired during the Cretaceous long interval of normal polarity. Comparison with Eurasian reference data shows significant counterclockwise rotation of a locality close to the Pamir wedge (R = 51 +/- 5 deg) and another counterclockwise rotation from the inner part of the basin (R = 15 +/- 5 deg). No significant rotations are observed at the two other localities on the periphery of the Tadzhik basin.

Bazhenov, Mikhail L.; Perroud, Herve; Chauvin, Annick; Burtman, Valentin S.; Thomas, Jean-Charles

1994-06-01

83

Strength and failure characteristics of Jurassic Red-Bed sandstone under cyclic wetting-drying conditions  

NASA Astrophysics Data System (ADS)

Due to cyclic fluctuations of reservoir water levels, bank slopes in drawdown areas are subjected to wetting-drying cycles. In order to reasonably evaluate the stabilities of sandstone slopes in the drawdown area of the Three Gorges Reservoir, it is a primary premise to obtain the strength and failure characteristics of the sandstones undergoing wetting-drying cycles. In this paper, the conventional triaxial compression tests, ultrasonic velocity and porosity measurements and microstructural observations were conducted on Jurassic Red-Bed sandstone (JRS) specimens undergoing wetting-drying cycles. The results from the triaxial experiments indicate that the peak strengths of the JRS are dramatically reduced after the first wetting-drying cycle, and then remain approximately constant with increasing number of wetting-drying cycles. The failure modes of the JRS samples undergoing different wetting-drying cycles are all brittle failures under low confining pressures ( ? 15 MPa). The decrease in P-wave velocity and increase in porosity with increasing number of wetting-drying cycles reveals the raise of damage level of the sandstone specimens, which is the main reason for the decline of peak strength. Detailed microstructural analysis has shown obvious argillization phenomena after undergoing wetting-drying cycles, which weakens the cements between grains in the sandstone and increases the damage of the sandstone.

Zhang, Zhenhua; Jiang, Qinghui; Zhou, Chuangbing; Liu, Xinting

2014-08-01

84

Characteristics of turbulent unidirectional flow over rough beds: Double-averaging perspective with particular focus on sand dunes and gravel beds  

Microsoft Academic Search

We address some unsolved methodological issues in modeling of natural rough-bed flows by critically examining existing approaches that parameterize rough-bed flows. These often utilize loosely defined variables. Here we suggest that double-averaging (in time and in a volume occupying a thin slab in a plane parallel to the mean bed) provides a rigorous, straightforward alternative that can aid in the

S. R. McLean; V. I. Nikora

2006-01-01

85

Depositional mechanisms controlling formation of coarse fluvial conglomerates in the lower triassic continental red beds of middle europe  

Microsoft Academic Search

Coarse fluvial conglomerates containing numerous cobbles and boulders occur in various formations within the Lower Triassic continental red beds of Middle Europe. The rudites mainly originate as longitudinal gravel bars in highly-braided river systems with narrowly-spaced and straight to slightly sinuous channels. The high-energy stream sedimentation and the frequent and rapid lateral shifting of the watercourses control origin, distribution and

Detlef Mader

86

Depositional mechanisms controlling formation of coarse fluvial conglomerates in the lower triassic continental red beds of middle europe  

Microsoft Academic Search

Coarse fluvial conglomerates containing numerous cobbles and boulders occur in various formations within the Lower Triassic continental red beds of Middle Europe. The rudites mainly originate as longitudinal gravel bars in highly-braided river systems with narrowly-spaced and straight to slightly sinuous channels. The high-energy stream sedimentation and the frequent and rapid lateral shifting of the watercourses control origin, distribution and

Detlef Mader

1985-01-01

87

Peat carrier increases inoculation success with Frankia on red alder (Alnus rubra Bong.) in fumigated nursery beds  

Microsoft Academic Search

Inoculation trials were set up in fumigated nursery beds for red alder (Alnus rubra Bong.) bare-root seedling production. Frankia inoculum was applied either as nodule homogenate or as pure culture (strain ArI5). The plots were laid out in 4 blocks of 8 treatments consisting of: control, nodule suspension, and three levels each of cell suspension and cells applied with a

K. J. Martin; Y. Tanaka; D. D. Myrold

1991-01-01

88

Continental Red Beds: How, Why, and When Can they Be Remagnetized, and What Would Don Elston Think?  

NASA Astrophysics Data System (ADS)

For logical reasons, continental red beds have served as the focus for thousands of paleomagnetic investigations; this author is becoming more and more convinced that the most accurate statements to make about how red beds are magnetized are: (1)no two red bed sequences are exactly the same and (2)understanding just how red beds are remagnetized (a nagging question pondered by several workers) may help us in more fully understanding aspects of how they acquire a geologically meaningful magnetization in the first place! Red beds of the Uinta Mountain Supergroup (UMS) serve as an excellent natural laboratory for studying magnetization acquisition and remagnetization processes. These rocks are exposed in the core of the Uinta Mountains, which formed during Laramide style shortening along the northern margin of the Colorado Plateau. In the eastern and central part of the range, strata are dominated by 3+ km of hematite-cemented medium to fine-grained sandstones, with relatively minor hematitic shales and conglomerates. Correlation of the upper part of the UMS section with the Chuar and Little Dal groups, and hence a mid-Neoproterozoic age for the strata, is based on the presence of the fossil Chuaria. At several localities in UMG strata, a dual polarity ChRM of about east-west declination and shallow inclination inferred to be primary) is smoothly and progressively unblocked between about 590 and 685°C, with no hint of changes in magnetic mineralogy and/or viscous behavior during unblocking. This magnetization provides a paleomagnetic pole of 0.8°N and 161.3°E (Weil,Geissman,and Ashby,2006, PC Res.) Several localities, in particular in the eastern part of the uplift, however, have been completely remagnetized and contain a pervasive and exceedingly well- defined, well-grouped magnetization that is consistent with a young, certainly post mid-Cretaceous, age of remagnetization. In chemical demagnetization, this secondary magnetization is completely removed over short time periods relative to the inferred primary remanence. Notably, none of the UMS strata investigated to date yield a secondary remanence of late Paleozoic age, which is not uncommon to Paleozoic and Precambrian rocks in the area. To provide a more accurate age of remagnetization, conglomerate tests are being performed on UMS cobbles from several sites in the oldest deposits flanking the uplift [Oligocene Bishop Conglomerate and Miocene Browns Park] that contain UMS clasts.

Geissman, J. W.

2006-12-01

89

Mapping the bathymetry of a turbid, sand-bed river using ground-based reflectance measurements and hyperspectral image data  

NASA Astrophysics Data System (ADS)

The Platte River in central Nebraska encompasses relatively stable, single-thread to island-braided reaches as well as wider, fully braided segments with highly mobile bar forms. Across this range of morphologies, suspended sediment and organic material contribute to turbid water conditions. In addition, the Platte is the focus of management activities intended to mitigate encroachment of vegetation and improve habitat for various migratory bird species, primarily by increasing the areal extent of shallow to slightly emergent mid-channel sand bars. The diversity of channel types and optical properties make this a challenging environment in which to implement a remote sensing approach, but the Platte also provides an opportunity for these methods to support management objectives. To evaluate the potential utility of remote sensing techniques along the Platte, we acquired hyperspectral image data, collected field spectra, and surveyed bed topography for three reaches. Ground-based measurements of reflectance R? were made above the water surface for flow depths d from 5 - 67 cm and a range of substrate types. An optimal band ratio analysis (OBRA) of these data, whereby regressions of log-transformed band ratios against measured depths were performed for all possible band combinations, yielded a strong, linear relationship (R2 = 0.95) between ln ({R593}/{R{647}) and d. Similar band ratio analyses were performed using reflectance spectra extracted from the hyperspectral image data for locations at which bed elevations were surveyed and compared to measured water surface elevations to calculate flow depths. Image-based OBRA produced variable results for the three sites. For a narrower, deeper reach lacking mobile mid-channel bars, a ln ({R490}/{R{638}) vs. d relation had an R2 of 0.83; applying this expression to the image generated a bathymetric map that agreed closely with our survey data. The other two sites featured fully braided morphologies, shallower depths, and numerous lobate bar forms, and image-based OBRA resulted in maximum R2 values of 0.47 and 0.53. Closer inspection of image-derived and surveyed cross-sections indicated that this poor agreement was partially explained by: 1) inaccurate geo-registration between the image and field data; 2) translation of the bar forms during the four days between the image acquisition and the completion of the field surveys; and 3) the presence of a range of depths within individual 0.75 m image pixels due to the abrupt variations in bathymetry associated with the bar-chute morphology. Examination of depth maps for the latter two reaches suggested that image-derived depths were actually more reliable than conventional accuracy metrics, such as R2, might seem to indicate. Moreover, applying the band ratio relation derived from field spectra directly to the image data yielded depth estimates that closely matched our field data. This latter finding implies that calibration based on field spectra is a viable alternative to pairing image pixels with ground-based depth measurements, which can be highly problematic for the reasons cited above.

Legleiter, C. J.; Kinzel, P. J.; Nelson, J. M.

2010-12-01

90

The influence of microbial mats on the formation of sand volcanoes and mounds in the Red Sea coastal plain, south Jeddah, Saudi Arabia  

NASA Astrophysics Data System (ADS)

Extensive areas covered by microbial mats have been found in the upper intertidal flats and supratidal pools in the Red Sea coastal plain of south Jeddah, Saudi Arabia. Numerous microbially controlled sediment-surface morphologies are evident, such as flat cohesive mats that commonly pass into mats with wrinkles, reticulates, and tufts, together with erosion pockets and mat chips. These microbial mats form cohesive surface layers that lead to biostabilization of the sediment surface. Fluidization of the underlying sediments is due to tidal influences and pressurized gas escape from decay and photosynthesis of microbial mats and causes deformation and rupture of the cohesive surface mat layer via vertical and sub-vertical pipes. Extrusion of fluidized sediments and water through these pipes leads to redeposition of sediment grains above the surface mat layer to form sand volcanoes and mounds. Most of the sand volcanoes present in the intertidal flats and supratidal pools show a symmetrical morphology, whereas in tidal channels asymmetrical forms are more common. Extrusion of underlying sediments through several adjacent vents leads to coalescence of sand volcanoes to form sand mounds. In this study sand volcanoes are also compared with other cone-like features from the Red Sea, such as gas domes and crab mounds. This comparison should help in differentiating similar cone-like features associated with microbial mats in the rock record.

Taj, Rushdi J.; Aref, Mahmoud A. M.; Schreiber, B. Charlotte

2014-08-01

91

Particulate matter filtration and seasonal nutrient dynamics in permeable carbonate and silicate sands of the Gulf of Aqaba, Red Sea  

Microsoft Academic Search

This study compares mineralization in permeable silicate and carbonate sands in the shallow shelf of the Gulf of Aqaba. From July 1999 to March 2000, we monitored concentrations of inorganic nutrients in water and pore water at two neighboring sites, one dominated by silicate, the other by carbonate sand. Although the carbonate was coarser than the quartz sand, organic matter,

M. Rasheed; M. I. Badran; M. Huettel

2003-01-01

92

Tectonic significance of porosity and permeability regimes in the red beds formations of the South Georgia Rift Basin  

NASA Astrophysics Data System (ADS)

A simple, new porosity/permeability-depth profile was developed from available laboratory measurements on Triassic sedimentary red beds (sandstone) from parts of the South Georgia Rift (SGR) basin in order to investigate the feasibility for long-term CO2 storage. The study locations were: Sumter, Berkeley, Dunbarton, Clubhouse Crossroad-3 (CC-3) and Norris Lightsey wells. As expected, both porosity and permeability show changes with depth at the regional scale that was much greater than at local scale. The significant changes in porosity and permeability with depth suggest a highly compacted, deformed basin, and potentially, a history of uplift and erosion. The permeability is generally low both at shallow (less than 1826 ft/556.56 m) and deeper depths (greater than 1826 ft/556.56 m). Both porosity and permeability follow the normal trend, decreasing linearly with depth for most parts of the study locations with the exception of the Norris Lightsey well. A petrophysical study on a suite of well logs penetrating the Norris Lightsey red beds at depths sampled by the core-derived laboratory measurements shows an abnormal shift (by 50%) in the acoustic travel time and/or in the sonic-derived P-wave velocity that indicates possible faulting or fracturing at depth. The departure of the Norris Lightsey's porosities and permeabilities from the normal compaction trend may be a consequence of the existence of a fault/fracture controlled abnormal pressure condition at depth. The linear and non-linear behaviors of the porosity/permeability distribution throughout the basin imply the composition of the SGR red beds, and by extension analog/similar Triassic-Jurassic formations within the Eastern North American Margin have been altered by compaction, uplift, erosion and possible faulting that have shaped the evolution of these Triassic formations following the major phase of rifting.

Akintunde, Olusoga M.; Knapp, Camelia C.; Knapp, James H.

2014-09-01

93

Bed Material Flux and Suspended Sand Measurements Within the Lower (Tidally Influenced) Mississippi River: Effects of Water Discharge Variability  

Microsoft Academic Search

Recent studies within the lower (tidally influenced) Mississippi River have sought to quantify bed-material transport rates using a repeat multibeam bathymetric methodology. Data were collected over range of water discharge conditions, and used to measure changes in bed elevation induced by the down-river migration of large dunes within a 24-hr survey period. A series of processing algorithms removed erroneous soundings,

J. A. Nittrouer; M. A. Allison; D. Mohrig

2006-01-01

94

Tectonic controls on the quality and distribution of Syn- to Post-Rift reservoir sands in the Southern Red Sea, offshore Western Yemen  

SciTech Connect

Previous geophysical and drilling results in the southern Red Sea, and the presence of numerous oil seeps, indicate that the syn- to post-rift section is prospective for oil and gas. The relatively high geothermal gradient offshore western Yemen makes intra-salt and post-salt reservoir sands the only viable exploration targets. The quality and distribution of the reservoir sands remains one of the main unknown risk factors, An improved understanding of the controls on deposition of these sands is achieved by use of LandSat data, which provide evidence of a regional tectonic framework involving NE/SW-trending oceanic transform faults which are expressed onshore as strike-slip features, in some cases representing reactivated Precambrian lineaments. These faults are thought to have played two fundamental roles in the Neogene to Recent evolution of the southern Red Sea - firstly by directing clastic input from the rising Yemen Highlands into offshore depocentres, and secondly by influencing the location of salt diapirs sourced by Upper Miocene evaporates. By considering these factors, together with the pattern of heat flow from the developing oceanic rift of the southern Red Sea, it is possible to delineate areas of offshore western Yemen where reservoir characteristics are likely to be most favourable.

Carter, J.M.L. [Petroleum Geologists Group Ltd., Reading (United Kingdom)

1995-08-01

95

Laboratory measurements to determine the grain size distribution of a sand-gravel bed surface and substrate: image analysis and CT scanner analysis  

NASA Astrophysics Data System (ADS)

Spatial and temporal changes in the grain size distribution are crucial to describe sediment transport and the related grain size selective processes. Two complimentary laboratory techniques are presented to determine such variations of the grain size distribution of the bed surface and substrate: (1) particle coloring in combination with photogrammetric analysis, and (2) core sampling combined with three-dimensional imaging. The two techniques will be used in later flume experiments that are aimed at studying the response of the river bed to nonsteady boundary conditions. In these flume experiments, the bed surface and substrate grain size distribution needs to be measured using reliable and preferentially rapid techniques. The techniques were evaluated conducting an experiment that partially reproduced the conditions of the later flume experiments. Three nonoverlapping grain size fractions (i.e. within the range of coarse sand to fine gravel) were used and they were painted in different colors. Various mixtures of the three grain size fractions were composed of various color combinations. Patches of the mixtures were installed in a pool. Images were taken of the bed surface and the images were analyzed using an algorithm based on color segmentation. The algorithm provides values of the surface fraction of the bed covered by a certain color (i.e. a size fraction). The influence of water depth on the results of the image analysis was studied. To this end pictures were taken without water and for three water depths. The image analysis results shows that the technique can be used effectively for images of the bed in a flume filled with water. This is beneficiary in applying the technique in the later flume experiments. The second technique comprises core sampling in combination with three-dimensional imaging. Samples taken with tube cores were fixed with wallpaper glue and analyzed using a micro computed tomography scanner (micro CT scanner). The scans provide a three-dimensional image of the sample from which the variation of the grain size distribution over the vertical is derived. The wallpaper glue fixing the sample deals well with wet sediment and does not affect the effectiveness of the x-rays of the CT scanner. The chosen viscosity of the glue makes it adequately infiltrate into the pores of the sample. The core sampling technique combined with the micro CT scanner analysis appears to be suitable to analyze the vertical variation of the grain size distribution in the bed.

Orru, C.; Blom, A.; Uijttewaal, W.

2012-12-01

96

Effects of human disturbance on movement, foraging and bed selection in red deer Cervus elaphus xanthopygus from the Wandashan Mountains, northeastern China  

Microsoft Academic Search

We characterized 716 sites (including 22 beds, 60 foraging and 604 movement sites) used by red deerCervus elaphus xanthopygus Milne-Edwards, 1867 in the Wandashan Mountains, northeastern China in the winter period. We used covariates for vegetation,\\u000a topography, disturbances by other ungulates, and disturbance by humans to develop movement, forage and bed site resource-selection\\u000a models. We used an information-theoretic approach to

Guangshun Jiang; Minghai Zhang; Jianzhang Ma

2007-01-01

97

Characterization of CO2-induced (?) bleaching phenomena in German red bed sediments by combined geochemical and evolved gas analysis  

NASA Astrophysics Data System (ADS)

We investigated varied coloured Buntsandstein and Rotliegend sandstones in Central Germany (Thuringian Vorderrhön, Altmark) by thermogravimetric/pyrolytic (DEGAS- directly coupled evolved gas analysis) and geochemical (ICP-MS/OES) means to evaluate geochemical/mineralogical characteristics of red bed rocks and their presumably altered, bleached modifications. Commonly bleaching of primary red bed sediments is regarded as a result of fluid-rock reactions by the participation of CO2. This study is performed in the framework of the special research program 'GEOTECHNOLOGIEN' (funded by the German Ministry of Education and Research - BMBF) and is part of two BMBF sponsored projects - 'COMICOR', an analogue study on potential effects of CO2-bearing fluids on Buntsandstein and Rotliegend deposits in Hesse and Thuringia and 'CLEAN', an enhanced gas recovery (EGR) pilot project in cooperation with GDF SUEZ E&P Deutschland GmbH. The intention of CLEAN is to evaluate the feasibility of EGR techniques and the suitability of depleted natural gas reservoirs for potential industrial CO2 sequestration projects. According to rock colour variations two slices of handspecimens (M49, A1) were split into 12 and 15 equally sized samples for analytical work. The medium grained Lower Buntsandstein sample M49 from Thuringia is of fluvial origin and partially bleached with transitions from red (unbleached) to light colours (bleached). Bulk rock geochemistry of red bed and bleached subsamples of M49 are almost similar, including rare earth element (REE) content. Only the content of iron and related metals is depleted in bleached samples compared to the red bed types. All PAAS normalized pattern of M49 show positive Eu and slightly negative Ce anomalies, most likely caused by the presence of apatite and illite in the rocks. The degassing behavior observed by DEGAS of M49 subsamples is mainly controlled by the breakdown of sheet silicates, hydroxides and hydrates, as well as of carbonates and sulphates. DEGAS pattern show no obvious systematic differences between the varied coloured zones of this specimen. Sample A1 consists of totally bleached medium grained, lithoclast rich Rotliegend sandstone which was deposited on a flood plain with braided rivers and aeolian dunes. Subsamples of A1 are grouped into three zones - all are bleached, with colours ranging from white to dark grey. Grey and dark grey zones (A1-1 to A1-6, A1-15) are cemented by Ca-rich carbonates and contain microscopically identified bitumina. In contrast the pore space of white zones (A1-7 to A1-14) is filled by anhydrite. These mineralogical differences are also reflected in the bulk rock geochemistry. In comparison to grey rocks white subsamples are depleted in iron and related elements as well as in REEs. Moreover, correlations between rock colour and degassing behavior exist. White samples display typical degassing signatures of sulphates, whereas dark grey zones reveal minor sulphate content, but also the presence of an additional S-species (sulphide) and CO2 (carbonate). Similar features were obtained regarding the specification and abundance of hydrocarbon components. In all samples of A1 methane, ethane and carbonylsulphide were detected, with higher contents in the more whitish parts. In grey rocks an additional, long-chained hydrocarbon component occurs. The relevance of this species is not yet resolved and will be investigated further in more detail. Mass spectrometric gas analytical and related geochemical data confirm major differences in rock composition of Buntsandstein and Rotliegend samples, mainly caused by primary rock composition and by the involvement of variable fluid composition during burial diagenetic alteration. In this study DEGAS was applied for the first time to characterize sandstone geochemistry. Our results constrain that this method might be a complementary analytical tool appropriate for petrological sedimentary research.

Hilse, Ulrike; Goepel, Andreas; Pudlo, Dieter; Heide, Klaus; Gaupp, Reinhard

2010-05-01

98

Voidage and pressure profile characteristics of sand-iron ore-coal-FCC single-particle systems in the riser of a pilot plant circulating fluidized bed  

SciTech Connect

Hydrodynamic behaviors of single system of particles were investigated in a circulating fluidized bed (CFB) unit. Particles belonging to Geldart groups A and B like sand of various sizes (90, 300, 417, 522, 599, and 622 mu m), FCC catalyst (120 mu m), iron ore (166 and 140 {mu} m), and coal (335 and 168 {mu} m) were used to study the hydrodynamic characteristics. Superficial air velocity used in the present study ranged between 2.01 and 4.681 m/s and corresponding mass fluxes were 12.5-50 kg/(m{sup 2} s). A CFB needs the creation of some special hydrodynamic conditions, namely a certain combination of superficial gas velocity, solids circulation rate, particle diameter, density of particle, etc. which can give rise to a state wherein the solid particles are subjected to an upward velocity greater than the terminal or free fall velocity of the majority of the individual particles. The hydrodynamics of the bed was investigated in depth and theoretical analysis is presented to support the findings. Based on gas-solid momentum balance in the riser, a distinction between apparent and real voidage has been made. The effects of acceleration and friction on the real voidage have been estimated. Results indicated a 0.995 voidage for higher superficial gas velocity of 4.681. m/s.

Das, M.; Meikap, B.C.; Saha, R.K. [Indian Institute for Technology, Kharagpur (India). Dept. for Chemical Engineering

2008-06-15

99

Impact of ozonation pre-treatment of oil sands process-affected water on the operational performance of a GAC-fluidized bed biofilm reactor.  

PubMed

Treatment of oil sands process-affected water (OSPW) using biodegradation has the potential to be an environmentally sound approach for tailings water reclamation. This process is both economical and efficient, however, the recalcitrance of some OSPW constituents, such as naphthenic acids (NAs), require the pre-treatment of raw OSPW to improve its biodegradability. This study evaluated the treatment of OSPW using ozonation followed by fluidized bed biofilm reactor (FBBR) using granular activated carbon (GAC). Different organic and hydraulic loading rates were applied to investigate the performance of the bioreactor over 120 days. It was shown that ozonation improved the adsorption capacity of GAC for OSPW and improved biodegradation by reducing NAs cyclicity. Bioreactor treatment efficiencies were dependent on the organic loading rate (OLR), and to a lesser degree, the hydraulic loading rate (HLR). The combined ozonation, GAC adsorption, and biodegradation process removed 62 % of chemical oxygen demand (COD), 88 % of acid-extractable fraction (AEF) and 99.9 % of NAs under optimized operational conditions. Compared with a planktonic bacterial community in raw and ozonated OSPW, more diverse microbial communities were found in biofilms colonized on the surface of GAC after 120 days, with various carbon degraders found in the bioreactor including Burkholderia multivorans, Polaromonas jejuensis and Roseomonas sp. PMID:25104220

Islam, Md Shahinoor; Dong, Tao; McPhedran, Kerry N; Sheng, Zhiya; Zhang, Yanyan; Liu, Yang; Gamal El-Din, Mohamed

2014-11-01

100

Tar sand  

SciTech Connect

Research on tar sand is briefly discussed. The research program supported by the US Department of Energy (DOE) includes a variety of surface extraction schemes. The University of Utah has process development units (PDU) employing fluidized bed, hot, water-assisted, and fluidized-bed/heat-pipe, coupled combustor technology. Considerable process variable test data have been gathered on these systems: (1) a rotary kiln unit has been built recently; (2) solvent extraction processing is being examined; and (3) an advanced hydrogenation upgrading scheme (hydropyrolysis) has been developed. The University of Arkansas, in collaboration with Diversified Petroleum, Inc., has been working on a fatty acid, solvent extraction process. Oleic acid is the solvent/surfactant. Solvent is recovered by adjusting processing fluid concentrations to separate without expensive operations. Western Research Institute has a PDU-scale scheme called the Recycle Oil Pyrolysis and Extraction (ROPE) process, which combines solvent (hot recycle bitumen) and pyrolytic extraction. 14 refs., 19 figs.

McLendon, T.R.; Bartke, T.C.

1990-01-01

101

Feedbacks among Floods, Pioneer Woody Vegetation, and Channel Change in Sand-Bed Rivers: Insights from Field Studies of Controlled Flood Releases and Models  

NASA Astrophysics Data System (ADS)

To investigate feedbacks between flow, geomorphic processes, and pioneer riparian vegetation in sand-bed rivers, we are combining field, hydraulic modeling, and laboratory simulations. Field studies have examined the response of woody riparian seedlings and channel morphology to prescribed dam-released floods that have been designed in part to maintain a native riparian woodland system on the Bill Williams River, Arizona, USA. Through monitoring of floods over a 7-year period, we have observed temporal and spatial variations in channel response. Floods have produced geomorphic and vegetation responses that varied with distance downstream of a dam, with scour and associated seedling mortality closer to the dam and aggradation and burial-induced mortality in a downstream reach with greater sediment supply. We also have observed that as vegetation grows beyond the seedling stage, its stabilizing effect on bars and its drag effect on flow progressively increases, such that floods of similar sizes but at different times may produce markedly different downstream responses as a function of vegetation characteristics. We also observed greater mortality among nonnative Tamarix spp. (tamarisk) seedlings than among native Salix gooddingii (Goodding's willow) seedlings, likely as a result of the greater first-year growth of willow relative to tamarisk. Combining field observations with modeling predictions of local hydraulics for the flood events we have studied is being used to draw linkages between hydraulics, channel change, and plant response at the patch and bar scale. In addition, mechanistic linkages are being examined using a field-scale laboratory stream channel, where seedlings of Tamarix spp. (tamarisk) and Populus fremontii (cottonwood) were planted and subjected to floods with varying sediment feed rate and plant configurations. The floods conveyed by our model channel were generally insufficient to scour the woody seedlings we planted, but changes in bar size and hydraulics were observed as a function of sediment feed and vegetation density and architecture.

Wilcox, A. C.; Shafroth, P. B.; Lightbody, A.; Stella, J. C.; Bywater-Reyes, S.; Kiu, L.; Skorko, K.

2012-04-01

102

The paleoclimatic and geochronologic utility of coring red beds and evaporites: a case study from the RKB core (Permian, Kansas, USA)  

NASA Astrophysics Data System (ADS)

Drill core is critical for robust and high-resolution reconstructions of Earth's climate record, as well demonstrated from both marine successions and modern long-lived lake systems. Deep-time climate reconstructions increasingly require core-based data, but some facies, notably red beds and evaporites, have garnered less attention for both paleoclimatic and geochronologic analyses. Here, we highlight studies from the Rebecca K. Bounds (RKB) core, a nearly continuous, >1.6 km drill core extending from the Cretaceous to the Mississippian, recovered from the US Midcontinent by Amoco Production Company in 1988, and serendipitously made available for academic research. Recent research conducted on this core illustrates the potential to recover high-resolution data for geochronologic and climatic reconstructions from both the fine-grained red bed strata, which largely represent paleo-loess deposits, and associated evaporite strata. In this case, availability of core was instrumental for (1) accessing a continuous vertical section that establishes unambiguous superposition key to both magnetostratigraphic and paleoclimatic analyses, and (2) providing pristine sample material from friable, soluble, and/or lithofacies and mineralogical species otherwise poorly preserved in surface exposures. The potential for high-resolution paleoclimatic reconstruction from coring of deep-time loess strata in particular remains severely underutilized.

Soreghan, Gerilyn S.; Benison, Kathleen C.; Foster, Tyler M.; Zambito, Jay; Soreghan, Michael J.

2014-08-01

103

Regeneration of sand waves after dredging  

Microsoft Academic Search

Sand waves are large bed waves on the seabed, being a few metres high and lying hundreds of metres apart. In some cases, these sand waves occur in navigation channels. If these sand waves reduce the water depth to an unacceptable level and hinder navigation, they need to be dredged. It has been observed in the Bisanseto Channel in Japan

M. A. F. Knaapen; S. J. M. H. Hulscher

2002-01-01

104

Palaeoenvironmental andstratigraphic aspects of animal traces and plant remains in Spanish Permian red beds (Peña Sagra, Cantabrian Mountains, Spain)  

Microsoft Academic Search

Various vertebrate and invertebrate traces and plants remains have been discovered in the Permian of Pico Paraes (Cantabrian Mountains). They occur in the Sagra Formation, a 400 m thick unit consisting of a vertical alternation of channels with conglomeratic sandstones and fossiliferous red siltstones with a caliche horizon at the top. The most common trace is Hyloidichnus major which is

E. Martínez-García; H KERP; C PARSONS

1997-01-01

105

Influence of riparian vegetation on channel widening and subsequent contraction on a sand-bed stream since European settlement: Widden Brook, Australia  

NASA Astrophysics Data System (ADS)

Widden Brook in the Hunter Valley, Australia, was first settled by Europeans in 1831 and had widened substantially by the 1870s due to frequent floods during a flood-dominated regime impacting on highly disturbed banks whose riparian trees had been either ringbarked or cleared, and whose understorey had been grazed. Catastrophic floods in 1950 (many), two in August 1952 and one in February 1955 effected the final phase of channel widening at the onset of a second flood-dominated regime more than half a century after the initial widening. Contraction has been active since 1963 by a combination of five biogeomorphic processes. Firstly, rapid channel widening, migration and cutoffs totally reworked the pre-European floodplain and were followed by active floodplain formation. Initial bar formation was replaced by sand splay and overbank deposition which constructed a new floodplain and narrower channel. Secondly, overwidened channel segments that were produced by the catastrophic 1955 flood have contracted since 1963 by the formation of up to four bank-attached, discontinuous benches below the floodplain. Each bench has a bar nucleus of pebbly coarse sand overlain by stratified fine-medium sand and mud. Colonisation by River Sheoaks (Casuarina cunninghamiana subsp. cunninghamiana) or grasses (Cynodon dactylon, Paspalum distichum, Pennisetum clandestinum) is important in converting bars to benches. Thirdly, narrower segments which developed since 1963 have contracted by small-scale accretion on both banks. These deposits are steeply dipping, interbedded sand and mud trapped by stoloniferous and rhizomatous grasses (C. dactylon, P. distichum, P. clandestinum) which also rapidly stabilise the deposits. Fourthly, rare laterally migrating, small radius bends have contracted by recent point bar formation greatly exceeding cutbank recession rates. Point bar formation is controlled by secondary currents producing inclined stratified coarse sands without the influence of vegetation. Lastly, rare, overwidened, non-migrating, large radius bends have greatly contracted by the infilling of dissecting chutes across the convex bank. Establishment of stoloniferous and rhizomatous clonal grasses (Phragmites australis, C. dactylon, P. distichum, P. clandestinum) is important in inducing sedimentation of the chutes. Contraction has produced a much narrower channel than the design width between river training fences which were installed progressively between the 1960s and 1990s. The recent flood history of Widden Brook has not included any catastrophic floods of a size similar to February 1955. Our work demonstrates that both trees and grasses can be associated with narrower channel widths and that the causal link between width and vegetation type is more complex than usually acknowledged.

Erskine, Wayne; Keene, Annabelle; Bush, Richard; Cheetham, Michael; Chalmers, Anita

2012-04-01

106

A playa deposit of pre-Yellow Sands age (upper Rotliegend\\/Weissliegend) in the Permian of northeast England  

Microsoft Academic Search

A complexly interbedded thin succession of sandstone, siltstone and mudstone beneath the Permian Yellow Sands Formation (upper Rotliegend\\/Weissliegend) was cored in a borehole 11 km off the coast of northeast England. The cored strata rest unconformably on fissured Westphalian B mudstone and mainly comprise low-dipping fine- to coarse-grained grey sandstone with unevenly spaced thinner dark-red to grey mudstone beds and

Brian R. Turner; Denys B. Smith

1997-01-01

107

Sand Stories  

NSDL National Science Digital Library

The objective of this project is to use a sample of sand from a give are to tell its geologic history. Each student is given a 50 mL tube of sand labeled with the latitude and longitude of where it was found. They must then use this information along with analysis of the sand itself to tell the story of its formation.

Christensen, Hilary

108

Modelling hydrodynamics in the Rio Paraná, Argentina: An evaluation and inter-comparison of reduced-complexity and physics based models applied to a large sand-bed river  

NASA Astrophysics Data System (ADS)

Depth-averaged velocities and unit discharges within a 30 km reach of one of the world's largest rivers, the Rio Paraná, Argentina, were simulated using three hydrodynamic models with different process representations: a reduced complexity (RC) model that neglects most of the physics governing fluid flow, a two-dimensional model based on the shallow water equations, and a three-dimensional model based on the Reynolds-averaged Navier-Stokes equations. Flow characteristics simulated using all three models were compared with data obtained by acoustic Doppler current profiler surveys at four cross sections within the study reach. This analysis demonstrates that, surprisingly, the performance of the RC model is generally equal to, and in some instances better than, that of the physics based models in terms of the statistical agreement between simulated and measured flow properties. In addition, in contrast to previous applications of RC models, the present study demonstrates that the RC model can successfully predict measured flow velocities. The strong performance of the RC model reflects, in part, the simplicity of the depth-averaged mean flow patterns within the study reach and the dominant role of channel-scale topographic features in controlling the flow dynamics. Moreover, the very low water surface slopes that typify large sand-bed rivers enable flow depths to be estimated reliably in the RC model using a simple fixed-lid planar water surface approximation. This approach overcomes a major problem encountered in the application of RC models in environments characterised by shallow flows and steep bed gradients. The RC model is four orders of magnitude faster than the physics based models when performing steady-state hydrodynamic calculations. However, the iterative nature of the RC model calculations implies a reduction in computational efficiency relative to some other RC models. A further implication of this is that, if used to simulate channel morphodynamics, the present RC model may offer only a marginal advantage in terms of computational efficiency over approaches based on the shallow water equations. These observations illustrate the trade off between model realism and efficiency that is a key consideration in RC modelling. Moreover, this outcome highlights a need to rethink the use of RC morphodynamic models in fluvial geomorphology and to move away from existing grid-based approaches, such as the popular cellular automata (CA) models, that remain essentially reductionist in nature. In the case of the world's largest sand-bed rivers, this might be achieved by implementing the RC model outlined here as one element within a hierarchical modelling framework that would enable computationally efficient simulation of the morphodynamics of large rivers over millennial time scales.

Nicholas, Andrew P.; Sandbach, Steven D.; Ashworth, Philip J.; Amsler, Mario L.; Best, James L.; Hardy, Richard J.; Lane, Stuart N.; Orfeo, Oscar; Parsons, Daniel R.; Reesink, Arnold J. H.; Sambrook Smith, Gregory H.; Szupiany, Ricardo N.

2012-10-01

109

Sedimentology of freshwater lacustrine shoreless in the Eocene Scheggs Bed of the Tipton Tongue of the Green River Formation, Sand Wash Basin, Northwest Colorado  

SciTech Connect

In this paper two freshwater shorelines, 40-274 ft thick, were investigated in the Scheggs Bed along Hardgrove Rim, 8 mi north of Maybell, Colorado. The rocks comprising the shorelines consist of interbedded quartzose sandstone, conglomerate, siltstone, shale, oil shale, carbonaceous shale, and coal. The shorelines are divisible into fluvial channel, mudflat, swamp, strandline, nearshore, and offshore lithofacies, which are identified by their stratigraphic positions, characteristic lithologies, and sedimentary structures. A columnar section is presented as a model for similar deposition in other members of the Green River Formation.

Roehler, H.W.

1990-12-01

110

Paleomagnetism of the Middle-Late Jurassic to Cretaceous red beds from the Peninsular Thailand: Implications for collision tectonics  

NASA Astrophysics Data System (ADS)

Jurassic to Cretaceous red sandstones were sampled at 33 sites from the Khlong Min and Lam Thap formations of the Trang Syncline (7.6°N, 99.6°E), the Peninsular Thailand. Rock magnetic experiments generally revealed hematite as a carrier of natural remanent magnetization. Stepwise thermal demagnetization isolates remanent components with unblocking temperatures of 620-690 °C. An easterly deflected declination ( D = 31.1°, I = 12.2°, ?95 = 13.9°, N = 9, in stratigraphic coordinates) is observed as pre-folding remanent magnetization from North Trang Syncline, whereas westerly deflected declination ( D = 342.8°, I = 22.3°, ?95 = 12.7°, N = 13 in geographic coordinates) appears in the post-folding remanent magnetization from West Trang Syncline. These observations suggest an occurrence of two opposite tectonic rotations in the Trang area, which as a part of Thai-Malay Peninsula received clockwise rotation after Jurassic together with Shan-Thai and Indochina blocks. Between the Late Cretaceous and Middle Miocene, this area as a part of southern Sundaland Block experienced up to 24.5° ± 11.5° counter-clockwise rotation with respect to South China Block. This post-Cretaceous tectonic rotation in Trang area is considered as a part of large scale counter-clockwise rotation experienced by the southern Sundaland Block (including the Peninsular Malaysia, Borneo and south Sulawesi areas) as a result of Australian Plate collision with southeast Asia. Within the framework of Sundaland Block, the northern boundary of counter-clockwise rotated zone lies between the Trang area and the Khorat Basin.

Yamashita, Itaru; Surinkum, Adichat; Wada, Yutaka; Fujihara, Makoto; Yokoyama, Masao; Zaman, Haider; Otofuji, Yo-ichiro

2011-02-01

111

The palaeomagnetism of (Mesoproterozoic) Eriksfjord Group red beds, South Greenland: multiphase remagnetization during the Gardar and Grenville episodes  

NASA Astrophysics Data System (ADS)

The Eriksfjord Group comprises ~3000 m of lavas and sediments rapidly deposited in a rift which developed within an Andean-type batholith in juxtaposition to the southern margin of the Laurentian Shield in South Greenland at ca. 1300 Ma. The lavas have been shown to preserve a detailed record of the geomagnetic field at the time of eruption, incorporating normal, reversed and transitional directions. This study has examined the magnetic properties of the intervening red sediments. They are found to possess a diagenetic remanence imparted by mediating fluids at later times. The impact of diagenesis is stratigraphically controlled: the base of the rift infill has magnetizations partially resident in magnetite which are either unstable to thermal cleaning or record a single polarity `B' magnetization (D/I = 284/67°, 31 samples, ?95 = 5.5°, palaeopole at 244.1°E, 47.5°N, dp/dm = 7.5/9.1° ). This corresponds in polarity, and closely in direction, to remanence observed in mid-Gardar gabbro giant dykes and dyke swarms emplaced along the axis of the rift system at ca. 1160 Ma the causative diagenetic magnetite appears to have grown from hydrothermal systems motivated by this magmatism in a sealed reservoir setting within the lower part of the rift infill. The Ilímaussaq alkaline igneous complex was emplaced into the southern extension of the rift at ca. 1130 Ma and possesses a dual polarity magnetization (D/I = 327/81°, ?95 = 6.4°, 10 sites). Eriksfjord lavas within the thermal aureole are overprinted to varying degrees by comparable magnetizations with steep inclinations. The mean pole position (283°E, 71°N, dp/dm = 12/12° ) lies near the apex of an apparent polar wander loop incorporating the Gardar Track (ca. 1300-1140 Ma) and the Keweenawan Track (ca. 1115-1050 Ma). Magnetizations in the Eriksfjord sedimentary succession have not been significantly reset by emplacement of the Ilímaussaq complex, but higher levels of the rift infill are dominated by an `A' magnetization (D/I = 305/34°, ?95 = 4.3°, 57 samples, palaeopole at 202.1°E, 32.4°N, dp/dm = 2.8/4.9° ) resident in haematite. The pole position does not correspond with any part of the Gardar Track, but does correlate with the return Keweenawan Track at ca. 1090 Ma, close to the time of Grenville orogenesis along the bordering southeastern margin of the Laurentian Shield. This remanence is attributed to diagenesis during extensional tectonism linked to the collapse of the Grenville Orogen formerly sited 100-200 km to the south.

Piper, J. D. A.; Thomas, D. N.; Share, S.; Rui, Zhang Qi

1999-03-01

112

An optical method of measuring the temperature in a fluidised bed combustor  

SciTech Connect

The paper analyses the dynamic aspects of the temperature field in a fluidised bed of solids particles (e.g., sand) in which a gaseous fuel is being burned. Such a hot bed emits electromagnetic radiation within the visible range and this can be recorded using a digital video camera. This fact has been used to develop a method for measuring the bed's temperature in the line of sight, through the quartz sides of the reactor. A solid probe is only used for calibration. Video recordings were obtained covering different regions of the bed over three wavelength bands, red, green and blue. In the course of an experiment, the mean temperature of the bed, measured with thermocouples, was raised from ambient to 1300 K, at a rate of {proportional_to} 1 K/s. The data collected were used for calibration, with the brightness of individual pixels converted to a temperature scale. The calibration can then be used to investigate the dynamic temperature distribution within the field of view, in individual elements of the bed. This can also help the study of heat transfer in the bed, its distribution and dissipation. Using this method, it is possible to make direct observations of the intermittent combustion of gaseous fuels in a bubbling fluidised bed. The results provide direct proof that the temperature gradients observed within such beds are associated with exothermic processes within fast moving bubbles. The method could be adapted to studying, e.g., the combustion of solid fuels. (author)

Zukowski, Witold; Baron, Jerzy; Bulewicz, Elzbieta M.; Kowarska, Beata [Cracow University of Technology, Faculty of Chemical Engineering and Technology, ul. Warszawska 24, 31-155 Krakow (Poland)

2009-07-15

113

Sand Dunes  

NSDL National Science Digital Library

Most will agree that nothing is more relaxing that lying or walking on a beach. While unwinding, have you ever wondered what caused those big mounds of sand that you crossed to get there? This topic in depth addresses this issue, featuring Web sites that discuss sand dune processes and formations. Some of the Web sites also discuss research, mining, and protection activities taking place in areas with sand dune.The Environment Bay of Plenty in New Zealand has an online brochure (1) dealing with the coastal processes that form sand dunes and beaches. From this site, users can obtain a general understanding of how dunes change with time. Ted Brambleby developed the second site (2) for the Marine Education Society of Australasia, Inc. This site gives a great overview of the functions and formations of dunes as well as describing their unique beauty and strategies on how to care for the dunes. Produced by Nova Scotia Museum of Natural History, the third site (3) is an online pamphlet discussing the physical features and locations of sand dunes in Nova Scotia. Visitors can also read about the ecosystem supported by these dynamic features. The forth site (4), created by John Mangimeli for the National Park Service, is a review of the scientific research completed throughout the years dealing with the geology of sand dunes. Visitors will find a more in-depth discussion about sand movement, sand accumulation, and sand dune features. The fifth site is a scientific paper (5 ) written by R.L. Van Dam, et al. Studying the long term evolution of the Parengarenga Sandspit, these researchers used ground penetrating radar (GPR) "to (1) explore the possibilities for mapping lateral continuity of the coffee rock, (2) study the sedimentary architecture and stratigraphy of the solitary dunes, and (3) reconstruct the wind regime on the sandspit." The next two sites discuss the threats to sand dunes and activities taking place to protect them. The Lake Michigan Federation addresses the issues of mining (6). Visitors can learn about alternatives to mining dune sand and the ecological values of dunes. The Department of Environmental Quality in Michigan created a site (7) that provides users with statistical information dealing with the amount of sand harvested, the regulations of mining, and maps of critical dune areas. After learning about the formation, processes, threats, and protections efforts; the last site (8), created by Eva Hornecker with the University of Bremen, will allow users to get a real sense of the beauty of the sand dunes. The site features a collage of spectacular images of the Great Sand Dunes in the San Luis Valley.

Enright, Rachel

114

Dual Fluidized Bed Biomass Gasification  

SciTech Connect

The dual fluidized bed reactor is a recirculating system in which one half of the unit operates as a steam pyrolysis device for biomass. The pyrolysis occurs by introducing biomass and steam to a hot fluidized bed of inert material such as coarse sand. Syngas is produced during the pyrolysis and exits the top of the reactor with the steam. A crossover arm, fed by gravity, moves sand and char from the pyrolyzer to the second fluidized bed. This sand bed uses blown air to combust the char. The exit stream from this side of the reactor is carbon dioxide, water and ash. There is a second gravity fed crossover arm to return sand to the pyrolysis side. The recirculating action of the sand and the char is the key to the operation of the dual fluidized bed reactor. The objective of the project was to design and construct a dual fluidized bed prototype reactor from literature information and in discussion with established experts in the field. That would be appropriate in scale and operation to measure the relative performance of the gasification of biomass and low ranked coals to produce a high quality synthesis gas with no dilution from nitrogen or combustion products.

None

2005-09-30

115

Have the northwest Negev dunefield sands reddened since their deposition?  

Microsoft Academic Search

Sand grain coating redness has been extensively both in coastal and inland desert dunes. In Israel, sand redness has been quantified by calculating a spectral redness index (RI) using single RGB bands (RI= R2\\/(B*G3)) from reflectance spectroscopy. The RI values have been correlated to ferric oxide mass that was dissolved from sand grain coatings (Ben Dor et al., 2006; Tsoar

Joel Roskin; Haim Tsoar; Dan G. Blumberg; Naomi Porat; Ofer Rozensten

2010-01-01

116

SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis  

USGS Publications Warehouse

Xenotime occurs as epitaxial overgrowths on detrital zircons in the Mesoproterozoic Revett Formation (Belt Supergroup) at the Spar Lake red bed-associated Cu-Ag deposit, western Montana. The deposit formed during diagenesis of Revett strata, where oxidizing metal-bearing hydrothermal fluids encountered a reducing zone. Samples for geochronology were collected from several mineral zones. Xenotime overgrowths (1–30 ?m wide) were found in polished thin sections from five ore and near-ore zones (chalcocite-chlorite, bornite-calcite, galena-calcite, chalcopyrite-ankerite, and pyrite-calcite), but not in more distant zones across the region. Thirty-two in situ SHRIMP U-Pb analyses on xenotime overgrowths yield a weighted average of 207Pb/206Pb ages of 1409 ± 8 Ma, interpreted as the time of mineralization. This age is about 40 to 60 m.y. after deposition of the Revett Formation. Six other xenotime overgrowths formed during a younger event at 1304 ± 19 Ma. Several isolated grains of xenotime have 207Pb/206Pb ages in the range of 1.67 to 1.51 Ga, and thus are considered detrital in origin. Trace element data can distinguish Spar Lake xenotimes of different origins. Based on in situ SHRIMP analysis, detrital xenotime has heavy rare earth elements-enriched patterns similar to those of igneous xenotime, whereas xenotime overgrowths of inferred hydrothermal origin have hump-shaped (i.e., middle rare earth elements-enriched) patterns. The two ages of hydrothermal xenotime can be distinguished by slightly different rare earth elements patterns. In addition, 1409 Ma xenotime overgrowths have higher Eu and Gd contents than the 1304 Ma overgrowths. Most xenotime overgrowths from the Spar Lake deposit have elevated As concentrations, further suggesting a genetic relationship between the xenotime formation and Cu-Ag mineralization.

Aleinikoff, John N.; Hayes, Timothy S.; Evans, Karl V.; Mazdab, Frank K.; Pillers, Renee M.; Fanning, C. Mark

2012-01-01

117

Water Research 38 (2004) 4760 Perchlorate removal in sand and plastic media bioreactors  

E-print Network

was examined using two side-by-side pilot-scale fixed-bed bioreactors packed with sand or plastic media; Fixed-bed reactor; Groundwater; Perchlorate; Sand 1. Introduction The large-scale contamination of many) and in the plastic medium reactor at flow rates of o0.063 L/s. Acetate in the sand reactor was removed from 4378

118

Booming Sands  

NSDL National Science Digital Library

This video segment, adapted from NOVA scienceNOW, presents basic concepts of physics behind booming sand dunes. See how surface tension affects potential and kinetic energy and how it all works together to create sound.

Foundation, Wgbh E.

2007-04-19

119

Luminescence dating of mojave desert sands  

NASA Astrophysics Data System (ADS)

Infra-red stimulated luminescence has been used to date periods of sand deposition in the Mojave Desert, California. Dates from the Cronese Basins, Kelso Dunes and Silver Lake are compared with published IRSL ages to provide evidence for discrete pulses of sand accretion during the late Pleistocene and Holocene, linked to both arid and pluvial climates. A critical factor in aeolian deposition throughout this area is shown to be the availability of sand from existing source areas.

Clarke, M. L.; Richardson, C. A.; Rendell, H. M.

120

Defrosting Sand  

NASA Technical Reports Server (NTRS)

2 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a patch of frost-covered, dark sand that, at the time the picture was acquired in June 2005, had begun to defrost. The frost is carbon dioxide. Dunes and other patches of sand are usually the first polar features to develop dark spots as the frost begins to sublime away.

Location near: 78.9oS, 80.2oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

2005-01-01

121

SLUDGE DEWATERING AND DRYING ON SAND BEDS  

EPA Science Inventory

Dewatering of water and wastewater treatment sludges was examined through mathematical modeling and experimental work. The various components of the research include: (1) chemical analyses of water treatment sludges, (2) drainage and drying studies of sludges, (3) a mathematical ...

122

Pneumatic and Hydraulic Systems in Coal Fluidized Bed Combustor  

Microsoft Academic Search

Problem statement: This study designed the pneumatic and hydraulic systems in coal fluidized bed combustor. These are fluidization of silica sand bed material, Air distributor, centrifugal fan, electric motor power drive and surface heat exchanger. Approach: The effects of increased gas velocity on silica sand and the resultant drag force formed the basic equations in fluidization. Air distributor was introduced

I. A. Adetunde

123

Bed Bugs  

MedlinePLUS

... pest control company. Top of page Bed Bug Biology Knowing what to look for is the first ... 2011: Bed Bug Grants Awarded Bed Bugs - Importance, Biology, and Control Strategies (Armed Forces Pest Management Board) ...

124

Defrosting Sand  

NASA Technical Reports Server (NTRS)

19 June 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark spots formed in carbon dioxide frost that covers the surfaces of patches of sand in the south polar region. As spring arrived this year in the martian southern hemisphere, so began the annual defrosting process. The fact that sand dunes begin to defrost earlier than other surfaces, and that the defrosting process involves the formation of spots like these, has been known since the earliest days of the MGS mission.

Location near: 66.8oS, 15.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

2005-01-01

125

Paleoenvironment and depositional environment of Miocene Olcese Sand, Bakersfield, California  

Microsoft Academic Search

The Olcese Sand near Bakersfield, California, contains evidence of a range of paleoenvironments including nonmarine, estuarine, and outer shelf depositional settings. Foraminifera from surface and subsurface samples place the Olcese in the Saucesian and Relizian of the California benthic stages. A pumice bed in the Olcese has been dated by fission track methods at 15.5 Ma. The Olcese Sand interfingers

H. C. Olson

1986-01-01

126

Completion methods in thick, multilayered tight gas sands  

E-print Network

Tight gas sands, coal-bed methane, and gas shales are commonly called unconventional reservoirs. Tight gas sands (TGS) are often described as formations with an expected average permeability of 0.1mD or less. Gas production rates from TGS reservoirs...

Ogueri, Obinna Stavely

2009-05-15

127

Completion methods in thick, multilayered tight gas sands  

E-print Network

Tight gas sands, coal-bed methane, and gas shales are commonly called unconventional reservoirs. Tight gas sands (TGS) are often described as formations with an expected average permeability of 0.1mD or less. Gas production rates from TGS reservoirs...

Ogueri, Obinna Stavely

2008-10-10

128

Industrial sand and gravel  

USGS Publications Warehouse

Domestic production of industrial sand and gravel in 2010 was about 26.5 Mt (29.2 million st), a 6-percent increased from 2009. Certain end uses of industrial sand and gravel, such as sand for container glass, golf course sand, recreational sand, specialty glass and water filtration, showed increased demand in 2010.

Dolley, T. P.

2011-01-01

129

Flue gas desulfurization in an internally circulating fluidized bed reactor  

Microsoft Academic Search

An internally circulating fluidized bed reactor (ICFBR) was used as a desulfurization apparatus in this study. The height of the bed was 2.5 m, and the inner diameter was 9 cm. The bed materials were calcium sorbent and silica sand. The effects of the operating parameters of the flue gas desulfurization including relative humidity, particle size of the calcium sorbent,

Chen Yeon Chu; Shyh Jye Hwang

2005-01-01

130

Evaluation of reed bed technology to dewater Army wastewater treatment plant sludge. Final report  

Microsoft Academic Search

As operator of over 100 small wastewater treatment plants (WWTPs), the Army has an interest in efficient and cost-effective sludge dewatering systems. Many Army wastewater treatment plants use conventional sand-drying beds to dewater sludge. However, sand drying involves costly regular removal of sludge, and sand-drying beds are vulnerable to operational problems with long drying periods during wet weather and sand

B. J. Kim; R. R. Cardenas; S. P. Chennupati

1993-01-01

131

The extraction of bitumen from western oil sands. Final report, July 1989--September 1993  

SciTech Connect

Research and development of surface extraction and upgrading processes of western tar sands are described. Research areas included modified hot water, fluidized bed, and rotary kiln pyrolysis of tar sands for extraction of bitumen. Bitumen upgrading included solvent extraction of bitumen, and catalytic hydrotreating of bitumen. Characterization of Utah tar sand deposits is also included.

Oblad, A.G.; Bunger, J.W.; Dahlstrom, D.A.; Deo, M.D.; Fletcher, J.V.; Hanson, F.V.; Miller, J.D.; Seader, J.D.

1994-03-01

132

Zevenhoven & Kilpinen NITROGEN 18.1.2004 4-35 4.11 Chemistry of nitrogen oxides at atmospheric fluidized bed  

E-print Network

fluidized bed combustion In fluidized bed combustion, the combustion takes place in a bed of particles that is being fluidized by means of air blown through the bed from below. The bed is composed of sand, ash, char residue, and, possibly, SO2 sorbent. Fluidized bed combustion may be divided into two main groups

Zevenhoven, Ron

133

Zevenhoven & Kilpinen NITROGEN 13.4.2002 4-34 4.11 Chemistry of nitrogen oxides at atmospheric fluidized bed  

E-print Network

fluidized bed combustion In fluidized bed combustion, the combustion takes place in a bed of particles that is being fluidized by means of air blown through the bed from below. The bed is composed of sand, ash, char residue, and, possibly, SO2 sorbent. Fluidized bed combustion may be divided into two main groups

Laughlin, Robert B.

134

Creating Sand Dunes  

NSDL National Science Digital Library

This experiment demonstrates the formation and movement of sand dunes. Students will simulate the effects of wind using a hair dryer on bare sand, then add stones and grass to observe how the effects are changed. They should be able to explain how sand dunes are formed, what circumstances effect the movement or formation of sand dunes, and relate this information to soil conservation.

1998-01-01

135

Industrial sand and gravel  

USGS Publications Warehouse

Domestic production of industrial sand and gravel in 2011 was about 30 Mt (33 million st), increasing slightly compared with 2010. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

Dolley, T. P.

2012-01-01

136

Industrial sand and gravel  

USGS Publications Warehouse

Domestic production of industrial sand and gravel in 2012 was about 49.5 Mt (55 million st), increasing 13 percent compared with that of 2011. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

Dolley, T. P.

2013-01-01

137

Sand Castle Saturation  

NSDL National Science Digital Library

In this activity about saturation (page 1 of PDF), learners will build a series of sand castle towers using a 16 oz cup. Learners begin with completely dry sand and then add a ¼ cup of water to the sand for each successive tower, each time measuring the height and width of the resulting sand mound until they make a tower that maintains the shape of the cup. Relates to the linked video, DragonflyTV: Sand Dunes.

Twin Cities Public Television, Inc.

2005-01-01

138

Unified View of Sediment Transport by Currents and Waves. I: Initiation of Motion, Bed Roughness, and Bed-Load Transport  

Microsoft Academic Search

Attention is given to the properties of sediment beds over the full range of conditions silts to gravel, in particular the effect of fine silt on the bed composition and on initiation of motion critical conditions is discussed. High-quality bed-load transport data sets are identified and analyzed, showing that the bed-load transport in the sand range is related to velocity

Leo C. van Rijn

2007-01-01

139

Evolution of radiative sand ridge field of the South Yellow Sea and its sedimentary characteristics  

Microsoft Academic Search

A sand ridge field of 22 470 km2 consists of fine sands and silts originally from the old Changjiang River sediment during the late Pleistocene period. Late\\u000a Holocene sand stratum with its well-preserved larmnary bedding of more clay particles reflects the influence from the Yellow\\u000a River. There are three genetic types of morphology of sand ridge field as follows: (i)

Ying Wang; Dakui Zhu; Kunyuan You; Shaoming Pan; Xiaodong Zhu; Xinqing Zou; Yongzhan Zhang

1999-01-01

140

Sand boils induced by the 1993 Mississippi River flood: Could they one day be misinterpreted as earthquake-induced liquefaction?  

USGS Publications Warehouse

In areas that are seismically active but lacking clear surficial faulting, many paleoearthquake studies depend on the interpretation of ancient liquefaction features (sand blows) as indicators of prehistoric seismicity. Sand blows, however, can be mimicked by nonseismic sand boils formed by water seeping beneath levees during floods. We examined sand boils induced by the Mississippi River flood of 1993 in order to compare their characteristics with sand blows of the New Madrid earthquakes of 1811-1812. We found a number of criteria that allow a distinction between the two types of deposits. (1) Earthquake-induced liquefaction deposits are broadly distributed about an epicentral area, whereas flood-induced sand boils are limited to a narrow band along a river's levee. (2) The conduits of most earthquake-induced sand blows are planar dikes, whereas the conduits of flood-induced sand boils are most commonly tubular. (3) Depression of the preearthquake ground surface is usual for sand blows, not for sand boils. (4) Flood-induced sand boils tend to be better sorted and much finer than sand-blow deposits. (5) Source beds for earthquake-induced deposits occur at a wide range of depths, whereas the source bed for sand boils is always near surface. (6) Materials removed from the walls surrounding the vent of a sand blow are seen inside sand blows, but are rarely seen inside sand boils. In general, flood-induced sand boils examined are interpreted to represent a less-energetic genesis than earthquake-induced liquefaction.

Li, Y.; Craven, J.; Schweig, E. S.; Obermeier, S. F.

1996-01-01

141

Red Fox Spatial Characteristics in Relation to Waterfowl Predation Author(s): Alan B. Sargeant  

E-print Network

Red Fox Spatial Characteristics in Relation to Waterfowl Predation Author(s): Alan B. SargeantNorth Dakota,and (4) observationson locations of red fox dens on SandLake National Wildlife areavailablethatdocumenttheuseofthese foodsourcesbyredfoxes. Thepurposesof thispaperareto discuss certainspatialcharacteristicsof red

Minnesota, University of

142

Sand waves, bars, and wind-blown sands of the Rio Orinoco, Venezuela and Colombia  

USGS Publications Warehouse

During March 1982, a reconnaissance study was carried out along a reach of the Rio Orinoco between Puerto Ayacucho and Ciudad Bolivar. This was the low-flow season. Samples of bed material and suspended sediments were collected, sonic records of the bed were obtained at several locations, and the exposed bars and sand waves were studied at four locations. Sounding records were obtained at two of these locations during June and November when flow covered the bars, and additional studies were made on the ground at some of these same sites during March 1983. The bed of the river is mostly sand with small quantities, about 5 percent by weight on average, of gravel. Suspended- sediment concentrations were low, ranging between 20 milligrams per liter above Rio Apure to almost 40 milligrams per liter below its confluence with the Rio Orinoco. The annual sediment load is estimated to be 240x10 6 megagrams per year. During the dry season, 35 percent or more of the bed is exposed in the form of large bars composed of many sand waves. Trade winds blow upriver and there is substantial upriver transport of river sediments by the wind. If the bars contain very coarse sands and fine gravel, deflation forms a lag deposit that armors the bar surface and prevents further erosion. Theoretical calculations show that the lower limit for the fraction of the bed that needs to be covered with nonmoving particles to prevent further erosion and the smallest size of the armor particles depend only on wind speed. Calculations of bed-material transport were made for a typical wide and narrow section of the river; the annual load, excluding the wash load, is about 30 x 10 6 megagrams per year. A new definition for wash load is proposed; it is material that can be suspended as soon as its motion is initiated. For the Rio Orinoco, this is material finer than 0.1 millimeters.

Nordin, Carl F.; Perez-Hernandez, David

1989-01-01

143

CONTRACTOR REPORT SAND927005  

E-print Network

CONTRACTOR REPORT SAND92­7005 Unlimited Release UC­261 Fatigue of Fiberglass Wind Turbine Blade . #12;Distribution CategoryUC-261 SAND92-7005 UnlimitedRelease PrintedAugust 1992 FATIGUE OF FIBERGLASS

144

China Dust and Sand  

... article title:  Dust and Sand Sweep Over Northeast China     View Larger Image ... these views of the dust and sand that swept over northeast China on March 10, 2004. Information on the height of the dust and an ...

2013-04-16

145

Mineral Sands Down Under  

NSDL National Science Digital Library

This resource describes what mineral sands are, and discusses the heavy, dark-colored minerals that they contain (rutile, ilmenite, zircon, monazite). A map shows locations of mineral sands deposits in Australia.

146

Sedimentological, Mineralogical and Geochemical Characterization of Sand Dunes in Saudi Arabia  

NASA Astrophysics Data System (ADS)

Sedimentological, mineralogical, morphological and geochemical studies of sand dunes from ten locations in Saudi Arabia were conducted in order to determine the differences between them and to find out the provenance and tectonic setting of these sand dunes. Sixty seven samples were collected from different sand dunes types ranging in morphology from linear, barchans, parabolic to stars dunes. In overall, the sand dunes are fine to coarse grained mean grain size, moderately sorted, near symmetrical skewness with mesokurtic distribution characterized sand dunes in most locations. The sand dunes grains are subrounded in all locations except in the Red sea, Qassim, central Arabia and the eastern province which showed sub-angular grains. The main mineral compositions of studied aeolian sand dunes are quartz, feldspar, calcite, and mica. Quartz is the dominant mineral in locations with significant amount of feldspars and mica in Najran, Red sea and Central Arabia locations. Moreover, calcite is present in Sakaka and NW Empty Quarter (Jafurah). Basement related sand dunes in Najran, Central Arabia and Red sea locations are sub-mature in terms of their mineralogical maturity. Whereas, sand dunes in other locations are texturally mature except those from the Red sea which showed sub-mature sand. The sands are classified as quartz arenite, except in the basement related sand dunes in Najran, central Arabia and the Red sea are ranging from sub-arkose, sub-litharenite and lithraenite. Morphologically, parallel to sub-parallel sand ridges with NE-SW orientation occurred in east and north parts of Empty Quarter (Najran and Jafurah) and NW-SE orientation in Dahna and Nafud deserts in central and north regions of Saudi Arabia. Parabolic sand dunes characterized the Nafud desert (Hail, Sakaka, Tayma locations). Barchans and star sand dunes characterize the Empty Quarter (Jafurah). Major, trace, and rare earth elements studies were carried out to determine the composition, provenance and tectonic history of the sand dunes. Geochemical analysis indicated that most of sand dunes are quartz arenite type, except in the Red sea, basement related central Saudi Arabia and Najran areas, the sand dunes are sub-arkoses, sub-litharenite and litharenite. The concentration of major,trace and rare elements showed active continental margins as a tectonic setting of Red sea, basement related Najran and central Arabia sand dune. In contrast, passive continental margins for the other locations. The distribution of major, trace and rare earth elements showed similarity in chemical composition between basement related sand dunes in Red sea, Najran and central Arabia.

Benaafi, Mohammed; Abdullatif, Osman

2014-05-01

147

The extraction of bitumen from western oil sands. Quarterly report, April--June 1993  

SciTech Connect

Accomplishments are briefly described for the following tasks: environmental impact statement; coupled fluidized bed bitumen recovery and coked sand combustion; water-based recovery of bitumen; rotary kiln process for recovery of bitumen and combustion of coke sand; recovery of bitumen from oil sands using fluidized bed reactors and combustion of spent sands in transport reactors; recovery of bitumen from oil sand and upgrading of bitumen by solvent extraction; catalytic and thermal upgrading of bitumens and bitumen-derived liquids; evaluation of Utah`s major oil sand deposits for the production of asphalt, high energy jet fuels and other specialty products; development of mathematical models for bitumen recovery and processing; completion of the cost examination study of the pilot plant restoration; development studies of equipment for three-product gravity separation of bitumen and sand; determine thickener requirements; and environmental studies of the North Salt Lake pilot plant rehabilitation and eventual operation and those environmental problems associated with eventual commercial products.

Oblad, A.G.; Bunger, J.W.; Deo, M.D.; Fletcher, J.V.; Hanson, F.V.; Miller, J.D.; Seader, J.D.

1993-07-01

148

A playa deposit of pre-Yellow Sands age (upper Rotliegend/Weissliegend) in the Permian of northeast England  

NASA Astrophysics Data System (ADS)

A complexly interbedded thin succession of sandstone, siltstone and mudstone beneath the Permian Yellow Sands Formation (upper Rotliegend/Weissliegend) was cored in a borehole 11 km off the coast of northeast England. The cored strata rest unconformably on fissured Westphalian B mudstone and mainly comprise low-dipping fine- to coarse-grained grey sandstone with unevenly spaced thinner dark-red to grey mudstone beds and laminae. Most of the sandstone beds are moderately to poorly sorted, fine- to very fine-grained subarkoses, with some sublitharenites, and are weakly to strongly cemented by dolomite (predominant), kaolinite and illite; sedimentary structures include subhorizontal plane to wavy lamination, ripple lamination, salt ridges and soft-sediment deformation. The siltstones and mudstones are more uniform in lithology and primary thickness; they contain sandstone-filled desiccation cracks, mudstone saucers and narrow sandstone dykes. Traces of possible former evaporite minerals are concentrated in the sandstones. By comparison with modem desert depositional environments, these strata are interpreted as the deposits of a playa occupying a depression on a stony, deflationary desert surface on a rock pediment or peneplain flanking the ancestral Pennines. The floor of the depression, which probably lay in the capillary fringe just above the contemporary water table, was periodically flooded so as to form a shallow playa lake. Comparable successions beneath the Yellow Sands have not been recorded from surface exposures in northeast England but mudstone beds at this stratigraphical level have been recorded in four other cored offshore boreholes and are presumed to be of similar origin to those described in this study. The stratigraphical position of these deposits suggests that they may be of pre-Yellow Sands age and coeval with or younger than the Basal Permian Breccia. Palynological analysis of mudstone samples from the core reveal the presence of plant material and indeterminate, pyrite-invested, possibly indigenous bisaccate pollen indicative of a vegetated hinterland with deposition occurring within a reducing, possibly sulphide-rich environment.

Turner, Brian R.; Smith, Denys B.

1997-12-01

149

Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands  

USGS Publications Warehouse

Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. ?? 2002 Published by Elsevier Science B.V.

Kenyon, N.H.; Akhmetzhanov, A.M.; Twichell, D.C.

2002-01-01

150

Aeolian Sand Transport with Collisional Suspension  

NASA Technical Reports Server (NTRS)

Aeolian transport is an important mechanism for the transport of sand on Earth and on Mars. Dust and sand storms are common occurrences on Mars and windblown sand is responsible for many of the observed surface features, such as dune fields. A better understanding of Aeolian transport could also lead to improvements in pneumatic conveying of materials to be mined for life support on the surface of the Moon and Mars. The usual view of aeolian sand transport is that for mild winds, saltation is the dominant mechanism, with particles in the bed being dislodged by the impact of other saltating particles, but without in-flight collisions. As the wind becomes stronger, turbulent suspension keeps the particles in the air, allowing much longer trajectories, with the corresponding increase in transport rate. We show here that an important regime exists between these two extremes: for strong winds, but before turbulent suspension becomes dominant, there is a regime in which in-flight collisions dominate over turbulence as a suspension mechanism, yielding transport rates much higher than those for saltation. The theory presented is based on granular kinetic theory, and includes both turbulent suspension and particle-particle collisions. The wind strengths for which the calculated transport rates are relevant are beyond the published strengths of current wind tunnel experiments, so these theoretical results are an invitation to do experiments in the strong-wind regime. In order to make a connection between the regime of saltation and the regime of collisional suspension, it is necessary to better understand the interaction between the bed and the particles that collide with it. This interaction depends on the agitation of the particles of the bed. In mild winds, collisions with the bed are relatively infrequent and the local disturbance associated with a collision can relax before the next nearby collision. However, as the wind speed increases, collision become more frequent and the agitation need not decay completely. In the regime of collisional suspension, the particles near the surface of the bed are assumed to be in a state of constant agitation. We indicate the conditions at the bed corresponding to the limits of saltation and collisional suspension and outline experiments, simulations, and modeling that have been undertaken to bridge these limits.

Jenkins, James T.; Pasini, Jose Miguel; Valance, Alexandre

2004-01-01

151

Foundry sand reclamation  

Microsoft Academic Search

A dry method of conditioning spent foundry sand is disclosed. After having sized the sand and removal of tramp metallic elements, the sand is subjected to a sequence of squeezing under a high-stress low kinetic energy system for a period of 5-30 minutes, and then propelled against a target with high-kinetic energy in the presence of a suction for several

A. J. Filipovitch; J. M. Bleuenstein

1984-01-01

152

Industrial sand and gravel  

USGS Publications Warehouse

In 2005, domestic production of industrial sand and gravel was about 31 Mt, a 5% increase from 2004. This increase was bouyed by robust construction and petroleum sectors of the US economy. Based on estimated world production figures, the United States was the world's leading producer and consumer of industrial sand and gravel. In the short term, local shortages of industrial sand and gravel will continue to increase.

Dolley, T. P.

2006-01-01

153

Sulfation and attrition of calcium sorbent in a bubbling fluidized bed  

Microsoft Academic Search

A bubbling fluidized bed reactor was used as a desulfurization apparatus in this study. The height of the bed was 2.5m, and the inner diameter was 9cm. The bed materials were calcium sorbent and silica sand. The effects of the operating parameters of the flue gas desulfurization including relative humidity, temperature, superficial gas velocity, and the particle size of calcium

Chen-Yeon Chu; Kuang-Wei Hsueh; Shyh-Jye Hwang

2000-01-01

154

Have the northwest Negev dunefield sands reddened since their deposition?  

NASA Astrophysics Data System (ADS)

Sand grain coating redness has been extensively both in coastal and inland desert dunes. In Israel, sand redness has been quantified by calculating a spectral redness index (RI) using single RGB bands (RI= R2/(B*G3)) from reflectance spectroscopy. The RI values have been correlated to ferric oxide mass that was dissolved from sand grain coatings (Ben Dor et al., 2006; Tsoar et al., 2008). Five main requirements have been proposed to enhance sand grain reddening: iron source from the weathering of iron-bearing minerals originating from parent rock or aeolian dust, minimum moisture content, oxidizing interstitial conditions, sediment stability and time. Thus, as many researches have suggested, when the source factors and climatic conditions are homogenous, redder sands indicate increased maturity. The northwest Negev dunefield has been classified by Tsoar et al. (2008) into 3 incursion units based upon contouring a grid of RI values for surface sand samples. The central incursion unit has been suggested to be younger due to relatively lower RI values that decrease to the east. This work tests the relationship between RI values and optically stimulated luminescence (OSL) ages of aeolian sand sampled from the near surface down to dune substrate throughout the NW Negev dunefield. Room-dried sand samples were measured in the laboratory with an ASD FieldSpec spectrometer and RI was calculated. Dune sections have been found to usually have similar RI values throughout their vertical profile despite OSL ages ranging between recent and Late Pleistocene. Along a W-E transect, RI values also tend to be similar. The central (Haluzza) part of the dunefield exhibits significantly lower RI values than RI of sands south of the Qeren Ridge. Dune base OSL ages possibly representing burial/stabilization of an initial incursion are slightly more mature in the south and may be evidence of the earliest dune incursion into the Negev. Thus the increased redness may be attributed to an older sand source but not to reddening in situ with time. Remotely sensed RI calculated from Landsat TM 5 (30 m pixel) RGB bands of bare Sinai sands also portrays the spatial RI difference between the central and southern sands. To summarize, we find no direct connection between dune sand deposition age and sand grain coating redness in the Negev dunes. It seems that stable aeolian sand and dune sections in the Negev have not reddened since their deposition. Sand grain coating redness was probably inherited during an earlier diagenetic stage in an environment different than today's. References Ben-Dor, E., Levin, N., Singer, A., Karnieli, A., Braun, O. & Kidron, G.J., 2006. Quantitative mapping of the soil rubification process on sand dunes using an airborne hyperspectral sensor. Geoderma, 131:1-21. Tsoar, H., Wenkart, R. & Blumberg, D.G., 2008. Formation and geomorphology of the north-western Negev sand dunes. In (Breckle, S.W., Yair, A.& Veste, M.) eds., Arid dunes ecosystems: The Nizzana sands in the Negev Desert. Springer pub. 475 pp.

Roskin, Joel; Tsoar, Haim; Blumberg, Dan G.; Porat, Naomi; Rozensten, Ofer

2010-05-01

155

Morphology and controls on the position of a gravel-sand transition: Fraser River, British Columbia  

NASA Astrophysics Data System (ADS)

river channels often exhibit a relatively abrupt transition from gravel- to sand-bedded conditions. The phenomenon is well documented, but few prior studies have analyzed the spatial variability through reaches where transitions occur. The downstream fining pattern observed in the Fraser River is cited as a classic example of an abrupt gravel-sand transition in a large alluvial channel. However, important questions regarding the exact location of the transition, its sedimentology and morphology, and what controls its location remain unanswered. Here we present observations of the downstream change in bed material grain size, river bed topography, and channel hydraulics through the reach within which the transition occurs. These observations indicate that the gravel-sand transition is characterized by a terminating gravel wedge, but there are patches of gravel downstream of the wedge forming a diffuse extension. We show that there is a dramatic decrease in shear stress at the downstream end of the wedge and a consequent cessation of general gravel mobility. We argue that the patches of gravel observed beyond the wedge are the result of enhanced mobility of fine gravel over a sand bed. We also find that sand in suspension declines rapidly at the downstream end of the wedge, suggesting that sand is delivered to the bed, completing the sedimentary conditions for a gravel-sand transition. We propose that the break in river slope associated with the transition is a consequential feature of the transition.

Venditti, Jeremy G.; Church, Michael

2014-09-01

156

Numerical simulation of turbulence and sediment transport of medium sand  

NASA Astrophysics Data System (ADS)

AbstractA model of <span class="hlt">sand</span> transport in water is produced by combining a turbulence-resolving large eddy simulation (LES) with a discrete element model (DEM) prescribing the motion of individual grains of medium <span class="hlt">sand</span>. The momentum effect of each particle on the fluid is calculated at the LES cell containing the particle, and the fluid velocity and pressure, interpolated to each particle center, is used to derive fluid force on each particle in the DEM. Eleven numerical experiments are conducted of an initially flat <span class="hlt">bed</span> of particles. The experiments span a range of motion, from essentially no motion to vigorous suspension. Hydraulic roughness is found to increase abruptly at the transition from <span class="hlt">bed</span> load to suspended load transport. Suspended sediment extracts momentum from the flow and decreases the rate of shear. Whereas, slightly higher in the flow, vertical drag by suspended grains damps turbulence and increases the rate of shear. Vertical sediment diffusivity and effective particle settling velocity are much smaller than is commonly assumed in suspended sediment models. The <span class="hlt">bed</span> load experiments suggest that saltation by itself is a poor model of <span class="hlt">bed</span> load <span class="hlt">sand</span> transport. In contrast to expectations from saltation models, the peak <span class="hlt">bed</span> load flux occurs at essentially the same level as the <span class="hlt">bed</span>, and grains move slowly in frequent contact with other grains. Higher- and faster-moving <span class="hlt">bed</span> load grains that can be considered to be in saltation represent a smaller portion of the total flux. Entrainment of <span class="hlt">bed</span> load grains occurs in response to fluid penetration of the <span class="hlt">bed</span> by high-vorticity turbulence structures embedded within broader high speed fluid regions referred to as a sweeps or high-speed wedges.</p> <div class="credits"> <p class="dwt_author">Schmeeckle, Mark W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">157</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/pp/1067c/report.pdf"> <span id="translatedtitle"><span class="hlt">Sand</span> dunes on the central Delmarva Peninsula, Maryland and Delaware</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Inconspicuous ancient <span class="hlt">sand</span> dunes are present in parts of the central Delmarva Peninsula, Maryland and Delaware. Many dunes are roughly V-shaped, built by northwest winds, especially on the east sides of some of the large rivers. On the uplands, the form and spacing of the dunes are variable. A surficial blanket composed mainly of medium and fine-grained <span class="hlt">sand</span>-the Parsonsburg <span class="hlt">Sand</span>-forms both the ancient dunes and the broad plains between the dunes. The <span class="hlt">sand</span> that forms the dunes is massive and intensely burrowed in the upper part; traces of horizontal or slightly inclined <span class="hlt">bedding</span> appear near the base. Quartz is the dominant mineral constituent of the <span class="hlt">sand</span>. Microline is abundant in the very fine to fine <span class="hlt">sand</span> fraction. The heavy-mineral assemblages (high zircon, tourmaline, rutile) are more mature than in most of the possible source rocks. The most abundant minerals in the clay-sized fraction are dioctahedral vermiculite, kaolinite, illite, montmorillonite, and gibbsite. The first four minerals are common in deposits of late Wisconsin and Holocene age. The gibbsite may be detrital, coming from weathered rocks of Tertiary age. The soil profile in the dune <span class="hlt">sand</span> is weakly to moderately developed. At or near the base of the Parsonsburg <span class="hlt">Sand</span> are peaty <span class="hlt">beds</span> that range in age from about 30,000 to about 13,000 radiocarbon years B.P. Microfloral assemblages in the peaty <span class="hlt">beds</span> suggest that the dunes on the uplands formed in a spruce parkland during the late Wisconsin glacial maximum. The river dunes may also be of late Wisconsin age, but could be Holocene.</p> <div class="credits"> <p class="dwt_author">Denny, Charles Storrow; Owens, James Patrick</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">158</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/mQHs38Vjj1_15"> <span id="translatedtitle">"<span class="hlt">Sand</span> Boil" on Bay Bridge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">"<span class="hlt">Sand</span> boil" or <span class="hlt">sand</span> volcano measuring 2 m (6.6 ft) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface <span class="hlt">sand</span> into a <span class="hlt">sand</span>-water slurry (liquefaction). Vented <span class="hlt">sand</span> contains-marine shell f...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-26</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">159</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/23115328"> <span id="translatedtitle">Performance of auger-type dry materials feeders when feeding oil <span class="hlt">sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Continuous, reproducible solids feeding has historically been difficult to achieve during surface mining-recovery process development studies with Uinta Basin oil <span class="hlt">sands</span>. In an effort to solve the problem, commercial bin-discharge feeders were tested for oil <span class="hlt">sands</span> feeding to rotary kiln and fluidized-<span class="hlt">bed</span> pyrolysis reactors and for feeding spent <span class="hlt">sands</span> from pyrolysis reactors to combustion reactors. Feeder experiments were conducted using</p> <div class="credits"> <p class="dwt_author">F. V. Hanson; J. V. Fletcher; H. Zheng</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">160</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/19220421"> <span id="translatedtitle">Dynamic <span class="hlt">Sand</span> Dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">When <span class="hlt">sand</span> falling in the spacing between two plates goes past an obstacle, a dynamic dune with a parabolic shape and an inner triangular region of nonflowing or slowly creeping <span class="hlt">sand</span> forms. The angle of the triangular zone increases with the height of the dune and saturates at a value determined by the geometry of the cell. The width of</p> <div class="credits"> <p class="dwt_author">Y. Amarouchene; J. F. Boudet; H. Kellay</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_7");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">161</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=34130"> <span id="translatedtitle">LONG TERM RECHARGE OF TRICKLING FILTER EFFLUENT INTO <span class="hlt">SAND</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">The rapid infiltration of trickling filter effluent onto natural delta <span class="hlt">sand</span> <span class="hlt">beds</span> at the Lake George Village Sewage Treatment Plant has been shown to produce the equivalent of tertiary treatment to the domestic wastewater since 1939 with no indication of exhaustion of the purifica...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">162</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cdc.gov/hab/redtide/default.htm"> <span id="translatedtitle"><span class="hlt">Red</span> Tide</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This CDC web page includes links to PDF or html formatted files containing information about Karenia brevis, a phytoplankton responsible for toxic <span class="hlt">red</span> tide events. Links include information about <span class="hlt">red</span> tide, what the CDC is doing about <span class="hlt">red</span> tide, links to other <span class="hlt">red</span> tide related sites, and publications about <span class="hlt">red</span> tide.</p> <div class="credits"> <p class="dwt_author">Control, U. S.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">163</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70031356"> <span id="translatedtitle">Field assessment of alternative <span class="hlt">bed</span>-load transport estimators</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Measurement of near-<span class="hlt">bed</span> sediment velocities with acoustic Doppler current profilers (ADCPs) is an emerging approach for quantifying <span class="hlt">bed</span>-load sediment fluxes in rivers. Previous investigations of the technique have relied on conventional physical <span class="hlt">bed</span>-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 <span class="hlt">bed</span> velocity measurements with <span class="hlt">bed</span>-load transport rates estimated from <span class="hlt">bed</span>-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 <span class="hlt">bed</span>-load samples is comparatively poor, suggesting that physical <span class="hlt">bed</span>-load sampling is ineffective for ground-truthing alternative techniques in large <span class="hlt">sand-bed</span> rivers. <span class="hlt">Bed</span> velocities measured in this study became more variable with increasing <span class="hlt">bed</span>-form wavelength at higher shear stresses. Under these conditions, <span class="hlt">bed</span>-form dimensions greatly exceed the region of the <span class="hlt">bed</span> ensonified by the ADCP, and the magnitude of the acoustic measurements depends on instrument location with respect to <span class="hlt">bed</span>-form crests and troughs. Alternative algorithms for estimating <span class="hlt">bed</span>-load transport from paired longitudinal profiles of <span class="hlt">bed</span> topography were evaluated. An algorithm based on the routing of local erosion and deposition volumes that eliminates the need to identify individual <span class="hlt">bed</span> forms was found to give results similar to those of more conventional dune-tracking methods. This method is particularly useful in cases where complex <span class="hlt">bed</span>-form morphology makes delineation of individual <span class="hlt">bed</span> forms difficult. ?? 2007 ASCE.</p> <div class="credits"> <p class="dwt_author">Gaeuman, G.; Jacobson, R.B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">164</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014CSR....76...64S"> <span id="translatedtitle">Dune-associated <span class="hlt">sand</span> fluxes at the nearshore termination of a banner <span class="hlt">sand</span> bank (Helwick <span class="hlt">Sands</span>, Bristol Channel)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Sand</span> dunes typically migrate in opposing directions along the two sides of <span class="hlt">sand</span> banks, reflecting a circulation driven by tidal current asymmetry, but it has been less clear how this pattern is distorted where banks intersect the coastline. The nearshore end of Helwick <span class="hlt">Sands</span>, a banner bank in the Bristol Channel, was surveyed three times over three years, twice with a high-resolution multibeam echo-sounder. In both multibeam surveys, an unusual geometry was found over the crest of the bank, whereby dunes connect continuously with the dunes on the flanks, despite the flank dunes migrating in opposite directions. The crestal dunes thus appear to realign rapidly. We suggest that this morphological behaviour arises here because of vigorous wave-driven transport and because surface waves propagate almost exactly parallel to the crestal dunes. <span class="hlt">Sand</span> transported parallel to the crestal dunes ensures that efficient reconnection occurs with dunes migrating along the flanks, particularly at low tide when wave currents are more strongly felt at the <span class="hlt">bed</span>.</p> <div class="credits"> <p class="dwt_author">Schmitt, Thierry; Mitchell, Neil C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">165</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ESRv..120....1G"> <span id="translatedtitle">Provenance and recycling of Arabian desert <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This study seeks to determine the ultimate origin of aeolian <span class="hlt">sand</span> in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi <span class="hlt">sands</span> from the <span class="hlt">Red</span> Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian <span class="hlt">sand</span> can be distinguished. Quartzose <span class="hlt">sands</span> with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali <span class="hlt">Sand</span> Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic <span class="hlt">sands</span> with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah <span class="hlt">Sand</span> Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled <span class="hlt">sand</span>, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune <span class="hlt">sands</span>, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al-Batin fossil alluvial fan or even from Mesozoic sandstones of the Arabian margin accreted to the Cenozoic Zagros orogen. Due to extensive recycling and the fact that zircon is so resistant to weathering and erosion, the U-Pb age signatures are much less powerful a tracer of sedimentary provenance than framework petrography and heavy minerals. Actualistic provenance studies of dune fields at subcontinental scale shed light on the generation and homogenization of aeolian <span class="hlt">sand</span>, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.</p> <div class="credits"> <p class="dwt_author">Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">166</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.1285G"> <span id="translatedtitle">Provenance and recycling of Arabian desert <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This study seeks to determine the ultimate origin of aeolian <span class="hlt">sand</span> in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi <span class="hlt">sands</span> from the <span class="hlt">Red</span> Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian <span class="hlt">sand</span> can be distinguished. Quartzose <span class="hlt">sands</span> with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali <span class="hlt">Sand</span> Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic <span class="hlt">sands</span> with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah <span class="hlt">Sand</span> Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled <span class="hlt">sand</span>, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune <span class="hlt">sands</span>, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al-Batin fossil alluvial fan or even from Mesozoic sandstones of the Arabian margin accreted to the Cenozoic Zagros orogen. Due to extensive recycling and the fact that zircon is so resistant to weathering and erosion, the U-Pb age signatures are much less powerful a tracer of sedimentary provenance than framework petrography and heavy minerals. Actualistic provenance studies of dune fields at subcontinental scale shed light on the generation and homogenization of aeolian <span class="hlt">sand</span>, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.</p> <div class="credits"> <p class="dwt_author">Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid; Al-Juboury, Ali</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">167</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cert.ucr.edu/research/ses/Comparison%20of%20the%20Effectiveness%20of%20a%20Fluidized%20Sand.pdf"> <span id="translatedtitle">Comparison of the Effectiveness of a Fluidized <span class="hlt">Sand</span> Bath and a Steam Chamber for Reactor Heating</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">coefficient from a gas fluidized <span class="hlt">bed</span> to a solid rod can be calculated as the sum of a gas convective component coefficient in a fluidized <span class="hlt">bed</span>:17,18 = = - + + + - + + - - - - - Nu h l k Pr 0.125(1 ){1 33Comparison of the Effectiveness of a Fluidized <span class="hlt">Sand</span> Bath and a Steam Chamber for Reactor Heating</p> <div class="credits"> <p class="dwt_author">California at Riverside, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">168</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.sfu.ca/~jvenditt/publications/agu_abst/AGU_2009_Venditti_Supply_limited_bedforms.pdf"> <span id="translatedtitle">Venditti, J. G., J.A. Nittrouer, R.P. Humphries, M.A. Allison (2009) Supply-Limited Bedforms in a Gravel-<span class="hlt">Sand</span> Transition, Eos Trans. AGU, 90(52), Fall Meet. Suppl., Abstract EP21B-0586.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">of the Fraser River in Southwestern British Columbia. We mapped the <span class="hlt">bed</span> using multi-beam swath-bathymetry (Reson Rivers often exhibit an abrupt transition from gravel to <span class="hlt">sand-bedded</span> conditions as river channel slopes</p> <div class="credits"> <p class="dwt_author">Venditti, Jeremy G.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">169</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70044777"> <span id="translatedtitle">Industrial <span class="hlt">sand</span> and gravel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Domestic production of industrial <span class="hlt">sand</span> and gravel in 2009 was about 27 Mt (30 million st), declining by 10 percent compared with 2008. Certain end uses of industrial <span class="hlt">sand</span> and gravel, such as foundry and glassmaking <span class="hlt">sand</span>, may have declined by a factor greater than 10 percent in 2009. U.S. apparent consumption was 24.7 Mt (27.2 million st) in 2009, down by 10 percent from the previous year, and imports declined to 83 kt (91,000 st).</p> <div class="credits"> <p class="dwt_author">Dolley, T. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">170</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22842765"> <span id="translatedtitle">CFD modelling of the fast pyrolysis of biomass in fluidised <span class="hlt">bed</span> reactors, Part A: Eulerian computation of momentum transport in bubbling fluidised <span class="hlt">beds</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The fluid–particle interaction inside a 150g\\/h fluidised <span class="hlt">bed</span> reactor is modelled. The biomass particle is injected into the fluidised <span class="hlt">bed</span> and the momentum transport from the fluidising gas and fluidised <span class="hlt">sand</span> is modelled. The Eulerian approach is used to model the bubbling behaviour of the <span class="hlt">sand</span>, which is treated as a continuum. The particle motion inside the reactor is computed</p> <div class="credits"> <p class="dwt_author">K. Papadikis; A. V. Bridgwater; S. Gu</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">171</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/183067"> <span id="translatedtitle">Drying of solids in fluidized <span class="hlt">beds</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Fluidized <span class="hlt">bed</span> 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 <span class="hlt">beds</span> 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 (<span class="hlt">sand</span>) 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 <span class="hlt">bed</span> driers is compared with that of batch fluidized <span class="hlt">bed</span> driers; the performance is predicted using batch kinetics, the residence time distribution of solids, and the contact efficiency between the phases.</p> <div class="credits"> <p class="dwt_author">Kannan, C.S.; Thomas, P.P.; Varma, Y.B.G. [Indian Inst. of Tech., Madras (India). Dept. of Chemical Engineering</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">172</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70017867"> <span id="translatedtitle"><span class="hlt">Sand</span> boils without earthquakes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Sedimentary deformation caused by liquefaction has become a popular means for inferring prehistoric strong earthquakes. This report describes a new mechanism for generating such features in the absence of earthquakes. <span class="hlt">Sand</span> boils and a 180-m-long <span class="hlt">sand</span> dike formed in Fremont Valley, California, when sediment-laden surface runoff was intercepted along the upslope part of a 500-m-long preexisting ground crack, flowed subhorizonally in the crack, and then flowed upward in the downslope part of the crack where it discharged as <span class="hlt">sand</span> boils on the land surface. If the <span class="hlt">sand</span> boils and their feeder dike were stratigraphically preserved, they could be misinterpreted as evidence for earthquake-induced liquefaction. -Authors</p> <div class="credits"> <p class="dwt_author">Holzer, T. L.; Clark, M. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">173</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/mQHs38Vjj1_83"> <span id="translatedtitle">Vent of <span class="hlt">Sand</span> Volcano</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">Vent of <span class="hlt">sand</span> volcano produced by liquefaction is about 4 ft across in strawberry field near Watsonville. Strip spanning vent is conduit for drip irrigation system. Furrow spacing is about 1.2 m (4 ft) on center....</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">174</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6841066"> <span id="translatedtitle"><span class="hlt">Sand</span> consolidation methods</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Methods are provided for selectively consolidating <span class="hlt">sand</span> grains within a subterranean formation. First an acidic salt catalyst such as ZnCl/sub 2/ is injected into the subterranean formation, wherein the acidic salt catalyst is adsorbed to the surface of the <span class="hlt">sand</span> grains. Next a polymerizable resin composition such as furfuryl alcohol oligomer is introduced into the well formation. Polymerization of the resin occurs upon exposure to the elevated well temperatures and contact with the acid salt catalyst adsorbed to the <span class="hlt">sand</span> grains. The polymerized resin serves to consolidate the surfaces of the <span class="hlt">sand</span> grains while retaining permeability through the pore spaces. An ester of a weak organic acid is included with the resin compositions to control the extent of a polymerization by consuming the water by-product formed druing the polymerization reaction.</p> <div class="credits"> <p class="dwt_author">Friedman, R.H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-24</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">175</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nano-link.org/educator-resources/browse-our-nanotech-curriculum/doc_download/48-magic-sand-experiment"> <span id="translatedtitle">Magic <span class="hlt">Sand</span> Movie</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This document from the Midwest Regional Center for Nanotechnology Education (NANO-LINK) is intended to be used with the other materials in the "magic <span class="hlt">sand</span>" series of classroom lessons, which are available here. This resource is a 4 minute video demonstrating the magic <span class="hlt">sand</span> experiment. In this experiment, students "will explore how the properties of a substance at the molecular level affects the way that it reacts and behaves."</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-03</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">176</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014GeoRL..41.6435B"> <span id="translatedtitle">Effect of <span class="hlt">bed</span> permeability and hyporheic flow on turbulent flow over <span class="hlt">bed</span> forms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">paper uses particle imaging velocimetry to provide the first measurements detailing the flow field over a porous <span class="hlt">bed</span> in the presence of <span class="hlt">bed</span> forms. The results demonstrate that flow downstream of coarse-grained <span class="hlt">bed</span> forms on permeable <span class="hlt">beds</span> is fundamentally different to that over impermeable <span class="hlt">beds</span>. Most significantly, the leeside flow separation cell is greatly modified by jets of fluid emerging from the subsurface, such that reattachment of the separated flow does not occur and the Reynolds stresses bounding the separation zone are substantially lessened. These results shed new light on the underlying flow physics and advance our understanding of both ecological and geomorphological processes associated with permeable <span class="hlt">bed</span> forms. Water fluxes at the <span class="hlt">bed</span> interface are critically important for biogeochemical cycling in all rivers, yet mass and momentum exchanges across the <span class="hlt">bed</span> interface are not routinely incorporated into flow models. Our observations suggest that ignoring such exchange processes in coarse-grained rivers may overlook important implications. These new results also provide insight to explain the distinctive morphology of coarse-grained <span class="hlt">bed</span> forms, the production of openwork textures in gravels, and the absence of ripples in coarse <span class="hlt">sands</span>, all of which have implications for modeling and prediction of sediment entrainment and flow resistance.</p> <div class="credits"> <p class="dwt_author">Blois, Gianluca; Best, James L.; Sambrook Smith, Gregory H.; Hardy, Richard J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">177</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014ESuDD...2..715S"> <span id="translatedtitle">The role of velocity, pressure, and <span class="hlt">bed</span> stress fluctuations in <span class="hlt">bed</span> load transport over <span class="hlt">bed</span> forms: numerical simulation downstream of a backward-facing step</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Bed</span> load transport over ripples and dunes in rivers exhibits strong spatial and temporal variability due to the complex turbulence field caused by flow separation at bedform crests. A turbulence-resolving flow model downstream of a backward-facing step, coupled with a model integrating the equations of motion of individual <span class="hlt">sand</span> grains, is used to investigate the physical interaction between <span class="hlt">bed</span> load motion and turbulence downstream of separated flow. Large <span class="hlt">bed</span> load transport events are found to correspond to low-frequency, positive pressure fluctuations. Episodic penetration of fluid into the <span class="hlt">bed</span> increases the <span class="hlt">bed</span> stress and moves grains. Fluid penetration events are larger in magnitude near the point of reattachment than further downstream. Models of <span class="hlt">bed</span> load transport over ripples and dunes must incorporate the effects of these penetration events of high stress and sediment flux.</p> <div class="credits"> <p class="dwt_author">Schmeeckle, M. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">178</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/87079"> <span id="translatedtitle"><span class="hlt">Bed</span> Bugs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">it is impossible to penetrate all hiding places, control is usually not immediate. A few living bugs may be seen for a week to 10 days after application. After 10 days, apply a second treatment to kill the just-hatching nymphs. The pesticides used for <span class="hlt">bed</span> bug... control have a short residual life, and so this second application is always needed. For heavily infected areas, it is recommended that a commercial pest control operator be consulted to control the infestation. Insecticide label clearances are subject...</p> <div class="credits"> <p class="dwt_author">Gold, Roger E.; Howell Jr., Harry N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-11-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">179</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1111/j.1365-3091.2005.00738.x"> <span id="translatedtitle">Regulation of <span class="hlt">sand</span> transport in the Colorado River by changes in the surface grain size of eddy sandbars over multi-year timescales</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">In settings where the transport of <span class="hlt">sand</span> is partially or fully supply limited, changes in the upstream supply of <span class="hlt">sand</span> are coupled to changes in the grain size of <span class="hlt">sand</span> on the <span class="hlt">bed</span>. In this manner, the transport of <span class="hlt">sand</span> under the supply-limited case is 'grain-size regulated'. Since the closure of Glen Canyon Dam in 1963, the downstream reach of the Colorado River in Marble and Grand Canyons has exhibited evidence of <span class="hlt">sand</span>-supply limitation. <span class="hlt">Sand</span> transport in the river is now approximately equally regulated by changes in the discharge of water and changes in the grain sizes of <span class="hlt">sand</span> on the channel <span class="hlt">bed</span> and eddy sandbars. Previous work has shown that changes in the grain size of <span class="hlt">sand</span> on the <span class="hlt">bed</span> of the channel (driven by changes in the upstream supply of <span class="hlt">sand</span> owing to both tributary floods and high dam releases) are important in regulating <span class="hlt">sand</span> transport over timescales of days to months. In this study, suspended-<span class="hlt">sand</span> data are analysed in conjunction with <span class="hlt">bed</span> grain-size data to determine whether changes in the grain size of <span class="hlt">sand</span> on the <span class="hlt">bed</span> of the channel or changes in the grain size of <span class="hlt">sand</span> on the surface of eddy sandbars have been more important in regulating <span class="hlt">sand</span> transport in the post-dam Colorado River over longer, multi-year timescales. The results of this study show that this combined theory- and field-based approach can be used to deduce which environments in a complicated setting are the most important environments for regulating sediment transport. In the case of the regulated Colorado River in Marble and Upper Grand Canyons, suspended-<span class="hlt">sand</span> transport has been regulated mostly by changes in the surface grain size of eddy sandbars. ?? 2005 International Association of Sedimentologists.</p> <div class="credits"> <p class="dwt_author">Topping, D. J.; Rubin, D. M.; Schmidt, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">180</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/sir/2008/5042/"> <span id="translatedtitle">Update on Regulation of <span class="hlt">Sand</span> Transport in the Colorado River by Changes in the Surface Grain Size of Eddy Sandbars over Multiyear Timescales</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">In settings where the transport of <span class="hlt">sand</span> is partially or fully supply limited, changes in the upstream supply of <span class="hlt">sand</span> are coupled to changes in the grain size of <span class="hlt">sand</span> on the <span class="hlt">bed</span>. In this manner, the transport of <span class="hlt">sand</span> under the supply-limited case is ?grain-size regulated.? Since the closure of Glen Canyon Dam in 1963, the downstream reach of the Colorado River in Marble and Grand Canyons has exhibited evidence of <span class="hlt">sand</span>-supply limitation. <span class="hlt">Sand</span> transport in the river is now about equally regulated by changes in the discharge of water and changes in the grain sizes of <span class="hlt">sand</span> on the channel <span class="hlt">bed</span> and eddy sandbars. Previous work has shown that changes in the grain size of <span class="hlt">sand</span> on the channel <span class="hlt">bed</span> (driven by changes in the upstream supply of <span class="hlt">sand</span> owing to both tributary floods and high dam releases) are important in regulating <span class="hlt">sand</span> transport over timescales of days to months. In this study, suspended-<span class="hlt">sand</span> data are analyzed in conjunction with <span class="hlt">bed</span> grain-size data to determine whether changes in the <span class="hlt">sand</span> grain size on the channel <span class="hlt">bed</span>, or changes in the <span class="hlt">sand</span> grain size on the surface of eddy sandbars, have been more important in regulating <span class="hlt">sand</span> transport in the postdam Colorado River over longer, multiyear timescales. The results of this study show that this combined theory- and field-based approach can be used to deduce which environments in a complicated setting are most important for regulating sediment transport. In the case of the regulated Colorado River in Marble and upper Grand Canyons, suspended-<span class="hlt">sand</span> transport has been regulated mostly by changes in the surface grain size of eddy sandbars.</p> <div class="credits"> <p class="dwt_author">Topping, David J.; Rubin, David M.; Schmidt, John C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_8");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_11");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">181</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://science.nasa.gov/science-news/science-at-nasa/2002/06dec_dunes/"> <span id="translatedtitle">City-swallowing <span class="hlt">Sand</span> Dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">At this Science at NASA site, you'll learn about the physics of <span class="hlt">sand</span> movement and the research done to understand mechanisms of dune migration. The physics and the landforms are interesting because granular materials like <span class="hlt">sand</span> show properties of both solids and fluids, including saltation, sheet flow, and avalanches. This site provides a summary of the physics involved along with photographs of <span class="hlt">sand</span> dunes on Mars, close-ups of <span class="hlt">sand</span> particles, and a <span class="hlt">sand</span> dune advancing on a town.</p> <div class="credits"> <p class="dwt_author">Bell, Trudy E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-19</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">182</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70028909"> <span id="translatedtitle">Giant <span class="hlt">sand</span> waves at the mouth of San Francisco Bay</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">A field of giant <span class="hlt">sand</span> waves, among the largest in the world, recently was mapped in high resolution for the first time during a multibeam survey in 2004 and 2005 through the strait of the Golden Gate at the mouth of San Francisco Bay in California (Figure la). This massive <span class="hlt">bed</span> form field covers an area of approximately four square kilometers in water depths ranging from 30 to 106 meters, featuring more than 40 distinct <span class="hlt">sand</span> waves with crests aligned approximately perpendicular to the dominant tidally generated cross-shore currents, with wavelengths and heights that measure up to 220 meters and 10 meters, respectively. <span class="hlt">Sand</span> wave crests can be traced continuously for up to two kilometers across the mouth of this energetic tidal inlet, where depth-averaged tidal currents through the strait below the Golden Gate Bridge exceed 2.5 meters per second during peak ebb flows. Repeated surveys demonstrated that the <span class="hlt">sand</span> waves are active and dynamic features that move in response to tidally generated currents. The complex temporal and spatial variations in wave and tidal current interactions in this region result in an astoundingly diverse array of <span class="hlt">bed</span> form morphologies, scales, and orientations. <span class="hlt">Bed</span> forms of approximately half the scale of those reported in this article previously were mapped inside San Francisco Bay during a multibeam survey in 1997 [Chin et al., 1997].</p> <div class="credits"> <p class="dwt_author">Barnard, P.L.; Hanes, D.M.; Rubin, D.M.; Kvitek, R.G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">183</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6536106"> <span id="translatedtitle">The extraction of bitumen from western tar <span class="hlt">sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report represents the work done during the year of May 8, 1987 to June 9, 1988. This year was the first year of a five-year program. The overall objective of the latter is to advance the technologies for recovering bitumen from the tar <span class="hlt">sands</span> by thermal and water assisted extraction means and upgrading of bitumen to synthetic crude, and conversion of bitumens to specialty products such as asphalt and resins to levels where realistic evaluations of technical and commercial potential can be made. Additionally, it is desired to have the data at a level which is adequate for design of pilot plants of appropriate size deemed necessary for commercial scale-up of the various processes being studied. The main areas for studies covered in this report are modelling and optimization of the hydropyrolysis process for upgrading bitumens, bitumen recovery by pyrolysis of the circle Cliffs tar <span class="hlt">sands</span> in a fluid <span class="hlt">bed</span>, pyrolysis of Whiterocks tar <span class="hlt">sand</span> in a rotary kiln, modelling of the combustor in the coupled fluidized <span class="hlt">bed</span> with interbed heat transfer using heat pipes, development of superior diluents for use in the water extraction of Utah's tar <span class="hlt">sands</span>, and fractionation and characterization of the bitumens from Asphalt Ridge and Sunnyside tar <span class="hlt">sands</span>. 169 refs., 60 figs., 31 tars.</p> <div class="credits"> <p class="dwt_author">Oblad, A.G.; Bunger, J.W.; Hanson, F.V.; Miller, J.D.; Seader, J.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">184</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10161422"> <span id="translatedtitle">The extraction of bitumen from western oil <span class="hlt">sands</span>. Quarterly report, July--September, 1993</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report cites task number followed by a brief statement of each task and the action taken this quarter. The tasks are: NEPA environmental information statement; coupled fluidized-<span class="hlt">bed</span> bitumen recovery and coked <span class="hlt">sand</span> combustion; water-based recovery of bitumen; rotary kiln process for recovery of bitumen and combustion of coke <span class="hlt">sand</span>; recovery of bitumen from oil <span class="hlt">sands</span> using fluidized <span class="hlt">bed</span> reactors and combustion of spent <span class="hlt">sands</span> in transport reactors; recovery of bitumen from oil <span class="hlt">sand</span> and upgrading of bitumen by solvent extraction; catalytic and thermal upgrading of bitumens and bitumen-derived liquids; evaluation of Utah`s major oil <span class="hlt">sand</span> deposits for the production of asphalt, high energy jet fuels, and other specialty products; development of mathematical models for bitumen recovery and processing; completion of the cost estimation study of the pilot plant restoration; development studies of equipment for three-product gravity separation of bitumen and <span class="hlt">sand</span>; development studies of disposal of <span class="hlt">sand</span> by conveying or pumping of high solids concentration <span class="hlt">sand</span>-water slurries; and environmental studies of the North Salt Lake pilot plant rehabilitation and eventual operation and those environmental problems associated with eventual commercial products.</p> <div class="credits"> <p class="dwt_author">Oblad, A.G.; Bunger, J.W.; Dahlstrom, D.A.; Deo, M.D.; Fletcher, J.V.; Hanson, F.V.; Miller, J.D.; Seader, J.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">185</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998APS..MAR.O1405M"> <span id="translatedtitle">Hysteresis and Contact forces in a Gas-fluidized <span class="hlt">Bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A gas-fluidized <span class="hlt">bed</span> consists of an assembly of granular material fluidized by an upflow of gas. The "melting" of a static assembly of <span class="hlt">sand</span> to the fluid state is hysteretic and proceeds through an intermediate state known as the "uniform fluid" which we have recently shown(Menon, N.; Durian, D.J. Particle motions in a gas-fluidized <span class="hlt">bed</span> of <span class="hlt">sand</span>. Phys. Rev. Lett., vol.79, 3407 (1997)) to be a weak, but motionless solid with enduring contacts between grains. We characterize the contact forces that stabilize this phase by measurements of the hysteresis in gas pressure vs gas velocity measurements and analyze them in terms of a yield stress for this soft solid. Since the chains of contact forces terminate at the boundaries of the <span class="hlt">bed</span>, interesting boundary effects are anticipated. We probe finite-size effects in the magnitude of these forces obtained both by varying grain-size as well as aspect ratio of the <span class="hlt">bed</span>.</p> <div class="credits"> <p class="dwt_author">Menon, Narayanan; Durian, Douglas</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">186</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.youtube.com/watch?v=JpLjR-qwYUs"> <span id="translatedtitle">Packed <span class="hlt">Bed</span> Reactor Experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p class="result-summary">The purpose of the Packed <span class="hlt">Bed</span> Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed <span class="hlt">bed</span> in reduced gravity. A packed <span class="hlt">bed</span> consists of a metal pipe ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">187</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://serc.carleton.edu/NAGTWorkshops/structure/SGT2012/activities/62804.html"> <span id="translatedtitle"><span class="hlt">Sand</span>-box experiment to investigate incremental and finite strain</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">100 level students, in groups of 3-6, are provided with small <span class="hlt">sand</span>-boxes fitted with a single moving end. Each box is filled with different colored layers of <span class="hlt">sand</span>, grit, and ploymer grains to simulate <span class="hlt">bedding</span>. Students progressivley shorten the layered section and record various parameters at each stage. Students then plot this data graphically and report back on the evolution of the structure (usually a fold), including it's geometry, scale, orientation, etc. This exercise is designed to encourage patient, careful analogue experimentation and data-recording; a successful exercise is assessed by detailed records and integration of different parameters towards a narrative of the deformation.</p> <div class="credits"> <p class="dwt_author">Graham Andrews, California S.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">188</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/1411.1959v1"> <span id="translatedtitle">Direct numerical simulations of aeolian <span class="hlt">sand</span> ripples</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Aeolian <span class="hlt">sand</span> <span class="hlt">beds</span> exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns out to be driven by resonant grain trajectories, whose length is close to a ripple wavelength and whose splash leads to a mass displacement towards the ripple crests. The pattern selection results from a compromise between this destabilizing mechanism and a diffusive downslope transport which stabilizes small wavelengths. The initial wavelength is set by the ratio of the sediment flux and the erosion/deposition rate, a ratio which increases linearly with the wind velocity. We show that this scaling law, in agreement with experiments, originates from an interfacial layer separating the saltation zone from the static <span class="hlt">sand</span> <span class="hlt">bed</span>, where momentum transfers are dominated by mid-air collisions. Finally, we provide quantitative support for the use the propagation of these ripples as a proxy for remote measurements of sediment transport.</p> <div class="credits"> <p class="dwt_author">Orencio Duran; Philippe Claudin; Bruno Andreotti</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-07</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">189</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25331873"> <span id="translatedtitle">Direct numerical simulations of aeolian <span class="hlt">sand</span> ripples.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Aeolian <span class="hlt">sand</span> <span class="hlt">beds</span> exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns out to be driven by resonant grain trajectories, whose length is close to a ripple wavelength and whose splash leads to a mass displacement toward the ripple crests. The pattern selection results from a compromise between this destabilizing mechanism and a diffusive downslope transport which stabilizes small wavelengths. The initial wavelength is set by the ratio of the sediment flux and the erosion/deposition rate, a ratio which increases linearly with the wind velocity. We show that this scaling law, in agreement with experiments, originates from an interfacial layer separating the saltation zone from the static <span class="hlt">sand</span> <span class="hlt">bed</span>, where momentum transfers are dominated by midair collisions. Finally, we provide quantitative support for the use of the propagation of these ripples as a proxy for remote measurements of sediment transport. PMID:25331873</p> <div class="credits"> <p class="dwt_author">Durán, Orencio; Claudin, Philippe; Andreotti, Bruno</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">190</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61323866"> <span id="translatedtitle">Initial operation of Conoco's South Texas fluidized <span class="hlt">bed</span> combustor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Conoco South Texas Multi-solids Fluid <span class="hlt">Bed</span> Combustor (MS-FBC) was developed for use in the pilot tar <span class="hlt">sands</span> steamflood project. The FBS had to be flexible to burn both Eagle Pass and Laredo coal, and petroleum coke. Limestone is used as the sorbent for SO2. Specifications for the MS-FBS process flow, including entrained <span class="hlt">bed</span> circulation, fuel and limestone feed, steam</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">191</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA07832&hterms=Arabic+Arabic+al-+arab+yah&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DArabic%2B%257C%2B%25D8%25A7%25D9%2584%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%25D8%25A9%2B%257C%2Bal-%25CA%25BBarab%25C4%25AByah%2B%257C%2B%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%252F%2526"> <span id="translatedtitle">Ganges Chasma <span class="hlt">Sand</span> Sheet</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">[figure removed for brevity, see original site] <p/> Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar <span class="hlt">sand</span> sea and at isolated dune fields at lower latitudes. <span class="hlt">Sand</span> seas on Earth are often called 'ergs,' an Arabic name for dune field. A <span class="hlt">sand</span> sea differs from a dune field in two ways: 1) a <span class="hlt">sand</span> sea has a large regional extent, and 2) the individual dunes are large in size and complex in form. <p/> Today's <span class="hlt">sand</span> sheet is located in the Ganges Chasma portion of Valles Marineris. As with yesterday's image, note that the dune forms are seen only at the margin and that the interior of the <span class="hlt">sand</span> sheet at this resolution appears to completely lack dune forms. <p/> Image information: VIS instrument. Latitude -6.4, Longitude 310.7 East (49.3 West). 19 meter/pixel resolution. <p/> Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. <p/> NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">192</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.waset.org/journals/ijcsse/v3/v3-3-27.pdf"> <span id="translatedtitle">RBF modeling of Incipient Motion of Plane <span class="hlt">Sand</span> <span class="hlt">Bed</span> Channels</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">To define or predict incipient motion in an alluvial channel, most of the investigators use a standard or modified form of Shields' diagram. Shields' diagram does give a process to determine the incipient motion parameters but an iterative one. To design properly (without iteration), one should have another equation for resistance. Absence of a universal resistance equation also magnifies the</p> <div class="credits"> <p class="dwt_author">Gopu Sreenivasulu; Bimlesh Kumar; Achanta Ramakrishna Rao</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">193</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001PhRvL..86.4286A"> <span id="translatedtitle">Dynamic <span class="hlt">Sand</span> Dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">When <span class="hlt">sand</span> falling in the spacing between two plates goes past an obstacle, a dynamic dune with a parabolic shape and an inner triangular region of nonflowing or slowly creeping <span class="hlt">sand</span> forms. The angle of the triangular zone increases with the height of the dune and saturates at a value determined by the geometry of the cell. The width of the dune, related to the radius of curvature at the tip, shows universal features versus its height rescaled by geometrical parameters. The velocity profile in the flowing part is determined and found to be nonlinear. The parabolic shape can be accounted for using a simple driven convection-diffusion equation for the interface.</p> <div class="credits"> <p class="dwt_author">Amarouchene, Y.; Boudet, J. F.; Kellay, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">194</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/fs20133074"> <span id="translatedtitle">A <span class="hlt">sand</span> budget for Marble Canyon, Arizona: implications for long-term monitoring of <span class="hlt">sand</span> storage change</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Recent U.S. Geological Survey research is providing important insights into how best to monitor changes in the amount of tributary-derived <span class="hlt">sand</span> stored on the <span class="hlt">bed</span> of the Colorado River and in eddies in Marble Canyon, Arizona. Before the construction of Glen Canyon Dam and other dams upstream, sandbars in Glen, Marble, and Grand Canyons were replenished each year by sediment-rich floods. <span class="hlt">Sand</span> input into the Colorado River is crucial to protecting endangered native fish, animals, and plants and cultural and recreational resources along the river in Glen Canyon National Recreation Area and Grand Canyon National Park.</p> <div class="credits"> <p class="dwt_author">Grams, Paul E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">195</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pmmh.espci.fr/fr/morphodynamique/papers/ARFM_Dunes.pdf"> <span id="translatedtitle"><span class="hlt">Sand</span> ripples and dunes 1 <span class="hlt">Sand</span> ripples and dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Sand</span> ripples and dunes 1 <span class="hlt">Sand</span> ripples and dunes Franc¸ois Charru Institut de M´ecanique des Fluides of environments: in water channels, rivers and coastal ar- eas (Best 2005), in deserts on Earth (Bagnold 1941, Pye</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">196</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61352147"> <span id="translatedtitle"><span class="hlt">Sand</span> consolidation methods</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A method is described for consolidating unconsolidated mineral particles including <span class="hlt">sand</span> in a subterranean petroleum formation penetrated by a well in fluid communication with at least a portion of the formation. The method consists of: (a) providing a fluid comprising a polymerizable resin, a polar organic diluent for the resin, and an oil soluble acid catalyst capable of causing polymerization</p> <div class="credits"> <p class="dwt_author">R. H. Friedman; B. W. Surles</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">197</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=physical+AND+science&pg=7&id=EJ878120"> <span id="translatedtitle">Building with <span class="hlt">Sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Children playing in damp <span class="hlt">sand</span> invariably try to make a tower or a tunnel. By providing experiences with a variety of materials, alone and together, teachers set up the conditions for children to learn through their senses and ensure that a class approaches a topic with a common set of experiences to build on. Learning about the properties of…</p> <div class="credits"> <p class="dwt_author">Ashbrook, Peggy</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">198</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5272458"> <span id="translatedtitle">Evaluation of fluid <span class="hlt">bed</span> heat exchanger optimization parameters. Final report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Uncertainty in the relationship of specific <span class="hlt">bed</span> material properties to gas-side heat transfer in fluidized <span class="hlt">beds</span> has inhibited the search for optimum <span class="hlt">bed</span> materials and has led to over-conservative assumptions in the design of fluid <span class="hlt">bed</span> heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid <span class="hlt">bed</span> heat transfer. A total of 31 tests were run with 18 different <span class="hlt">bed</span> material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized <span class="hlt">bed</span> 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 <span class="hlt">bed</span> material selection was conducted. For the fluidized <span class="hlt">bed</span> evaporator, it was found that zircon <span class="hlt">sand</span> was the best choice among materials tested in this program, and that the selection of <span class="hlt">bed</span> material substantially influences the overall system costs. The optimized fluid <span class="hlt">bed</span> heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid <span class="hlt">bed</span> 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 <span class="hlt">bed</span> approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of <span class="hlt">bed</span> materials for fluidized <span class="hlt">bed</span> heat exchanger applications, based upon findings of the study reported herein.</p> <div class="credits"> <p class="dwt_author">Not Available</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">199</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830000349&hterms=tar+sand&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtar%2Bsand"> <span id="translatedtitle">Extracting Oil From Tar <span class="hlt">Sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Recovery of oil from tar <span class="hlt">sands</span> possible by batch process, using steam produced by solar heater. In extraction process, solar heater provides steam for heating solvent boiler. Boiling solvent removes oil from tar <span class="hlt">sands</span> in Soxhlet extractor.</p> <div class="credits"> <p class="dwt_author">Ford, L. B.; Daly, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">200</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA07822&hterms=Arabic+Arabic+al-+arab+yah&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DArabic%2B%257C%2B%25D8%25A7%25D9%2584%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%25D8%25A9%2B%257C%2Bal-%25CA%25BBarab%25C4%25AByah%2B%257C%2B%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%252F%2526"> <span id="translatedtitle">Northern <span class="hlt">Sand</span> Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">[figure removed for brevity, see original site] <p/> Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar <span class="hlt">sand</span> sea and at isolated dune fields at lower latitudes. <span class="hlt">Sand</span> seas on Earth are often called 'ergs,' an Arabic name for dune field. A <span class="hlt">sand</span> sea differs from a dune field in two ways: 1) a <span class="hlt">sand</span> sea has a large regional extent, and 2) the individual dunes are large in size and complex in form. <p/> This VIS image was taken at 82 degrees North latitude during Northern spring. The image is completely dominated by dunes. In <span class="hlt">sand</span> seas, it is very common for a single type of dune to occur, and for a single predominate wind to control the alignment of the dunes. <p/> Image information: VIS instrument. Latitude 82.2, Longitude 152.5 East (207.5 West). 19 meter/pixel resolution. <p/> Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. <p/> NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_9");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return 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showDiv("page_12");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">201</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22703020"> <span id="translatedtitle">Catalytic pyrolysis of woody biomass in a fluidized <span class="hlt">bed</span> reactor: Influence of the zeolite structure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Catalytic pyrolysis of biomass from pine wood was carried out in a fluidized <span class="hlt">bed</span> reactor at 450°C. Different structures of acidic zeolite catalysts were used as <span class="hlt">bed</span> material in the reactor. Proton forms of Beta, Y, ZSM-5, and Mordenite were tested as catalysts in the pyrolysis of pine, while quartz <span class="hlt">sand</span> was used as a reference material in the non-catalytic</p> <div class="credits"> <p class="dwt_author">A. Aho; N. Kumar; K. Eränen; T. Salmi; M. Hupa; D. Yu. Murzin</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">202</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55182017"> <span id="translatedtitle">Geological and oceanographic perspectives on event <span class="hlt">bed</span> formation during Hurricane Katrina</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Storm deposits in ancient shelf sediments typically form thick sequences of interbedded <span class="hlt">sand</span> and mud deposited during shoreline regression, whereas modern shelf sediments are generally thin veneers deposited during shoreline transgression. In this paper we present a preliminary comparison between ancient and modern storm <span class="hlt">beds</span> deposited in these disparate contexts. Hurricane Katrina deposited a storm <span class="hlt">bed</span> on the Louisiana shelf</p> <div class="credits"> <p class="dwt_author">T. R. Keen; Y. Furukawa; S. J. Bentley; R. L. Slingerland; W. J. Teague; J. D. Dykes; C. D. Rowley</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">203</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geo.edu.ro/sgr/mod/downloads/PDF/Sylvester_Sedimentology_51-945.pdf"> <span id="translatedtitle">Textural trends in turbidites and slurry <span class="hlt">beds</span> from the Oligocene flysch of the East Carpathians, Romania</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Deep-water sandstone <span class="hlt">beds</span> of the Oligocene Fusaru Sandstone and Lower Dysodilic Shale, exposed in the Buza ùu Valley area of the East Carpathian flysch belt, Romania, can be described in terms of the standard turbidite divisions. In addition, mud-rich <span class="hlt">sand</span> layers are common, both as parts of otherwise 'normal' sequences of turbidite divisions and as individual event <span class="hlt">beds</span>. Eleven units,</p> <div class="credits"> <p class="dwt_author">Zoltan Sylvester; Donald R. Lowe</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">204</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60232282"> <span id="translatedtitle">Special report: Athabasca tar <span class="hlt">sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A synthetic crude oil is being produced from the Athabasca oil <span class="hlt">sands</span> region of northeastern Alberta. The Athabasca operations are broken down into 3 divisions: mining, extraction of oil from the <span class="hlt">sand</span>, and pipelining to market. The entire project, operated by Great Canadian Oil <span class="hlt">Sands</span>, Ltd., an affiliate of Sun Oil Co., is self-sufficient except for the water supply. By-</p> <div class="credits"> <p class="dwt_author">W. A. Bachman; D. H. Stormont</p> <p class="dwt_publisher"></p> <p class="publishDate">1967-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">205</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26658900"> <span id="translatedtitle">Sheet flow and suspension of <span class="hlt">sand</span> in oscillatory boundary layers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">after revisionTime-dependent measurements of flow velocities and sediment concentrations were conducted in a large oscillating water tunnel. The measurements were aimed at the flow and sediment dynamics in and above an oscillatory boundary layer in plane <span class="hlt">bed</span> and sheet-flow conditions. Two asymmetric waves and one sinusoidal wave were imposed using quartz <span class="hlt">sand</span> with D50 = 0.21 mm. A new electro-resistance</p> <div class="credits"> <p class="dwt_author">Jan S. Ribberink; Abdullah A. Al-Salem</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">206</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5451768"> <span id="translatedtitle">Initial operation of Conoco's South Texas fluidized <span class="hlt">bed</span> combustor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Conoco South Texas Multi-solids Fluid <span class="hlt">Bed</span> Combustor (MS-FBC) was developed for use in the pilot tar <span class="hlt">sands</span> steamflood project. The FBS had to be flexible to burn both Eagle Pass and Laredo coal, and petroleum coke. Limestone is used as the sorbent for SO2. Specifications for the MS-FBS process flow, including entrained <span class="hlt">bed</span> circulation, fuel and limestone feed, steam generation loop, flue gas cleanup, and ash removal system, are given. After initial operations, modifications to the entrained <span class="hlt">bed</span>, the startup preheater, and the blowers were made. The Conoco MS-FBS has met or exceeded all of its design requirements.</p> <div class="credits"> <p class="dwt_author">Jones, O.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">207</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6826638"> <span id="translatedtitle">Fluidized <span class="hlt">bed</span> combustion</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The invention relates to fluidized <span class="hlt">bed</span> combustors that might tilt in use so that the depth of the <span class="hlt">bed</span> progressively changes across its width. Air is supplied from two or more sources and means are provided to vary the flow from the sources as the <span class="hlt">bed</span> tilts so that the air supplied to the portion of the <span class="hlt">bed</span> of increased depth is increased relatively to the air supplied to the portion of the <span class="hlt">bed</span> of lesser depth.</p> <div class="credits"> <p class="dwt_author">Hodgkin, A.F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-12-16</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">208</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40676912"> <span id="translatedtitle">Heavy metal removal from wastewater in fluidized <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">An innovative process for removing heavy metals including Cu, Ni and Zn from industrial wastewater has been developed. The new technology was based on inducing the nucleated precipitation of heavy metals on the <span class="hlt">sand</span> surface in a fluidized <span class="hlt">bed</span> reactor. The results showed that pH had a great effect on heavy metal removal efficiency and the optimum pH was about</p> <div class="credits"> <p class="dwt_author">Ping Zhou; Ju-Chang Huang; Alfred W. F Li; Shirly Wei</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">209</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22939670"> <span id="translatedtitle">Experimental study and modeling of fluidized <span class="hlt">bed</span> coating and agglomeration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This work deals with the fluidized <span class="hlt">bed</span> coating and agglomeration of solid particles. The effect of particle size on coating criteria was investigated using <span class="hlt">sand</span> particles as the coating support and aqueous solutions containing NaCl as coating liquid. The results showed that both growth rate and efficiency increase with decreasing the particle size. The growth was mainly governed by layering</p> <div class="credits"> <p class="dwt_author">K. Saleh; D. Steinmetz; M. Hemati</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">210</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013WRR....49.1314M"> <span id="translatedtitle">Origin of hysteresis in <span class="hlt">bed</span> form response to unsteady flows</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Field and laboratory studies indicate that changes in riverbed morphology often lag changes in water discharge. This lagged response produces hysteresis in the relationship between water discharge and <span class="hlt">bed</span> form geometry. To understand these phenomena, we performed flume experiments to observe the response of a <span class="hlt">sand</span> <span class="hlt">bed</span> to step increases and decreases in water discharge. For an abrupt rise in discharge, we observed that <span class="hlt">bed</span> forms grew rapidly by collision and merger of <span class="hlt">bed</span> forms migrating with different celerities. Growth rate slowed as <span class="hlt">bed</span> forms approached equilibrium with the higher discharge regime. After an abrupt discharge drop, <span class="hlt">bed</span> form decay occurred through formation of smaller secondary <span class="hlt">bed</span> forms, in equilibrium with the lower discharge, which cannibalized the original, relict features. We present a simple model framework to quantitatively predict time scales of <span class="hlt">bed</span> form adjustment to flow changes, based on equilibrium <span class="hlt">bed</span> form heights, lengths, and celerities at low and high flows. For rising discharge, the model assumes that all <span class="hlt">bed</span> form collisions result in irreversible merger, due to a dispersion of initial celerities. For falling discharge, we derive a diffusion model for the decay of relict high-stage features. Our models predict the form and time scale of experimental <span class="hlt">bed</span> form adjustments. Additional experiments applying slow and fast triangular flood waves show that <span class="hlt">bed</span> form hysteresis occurs only when the time scale of flow change is faster than the modeled (and measured) <span class="hlt">bed</span> form adjustment time. We show that our predicted adjustment time scales can also be used to predict the occurrence of <span class="hlt">bed</span> form hysteresis in natural floods.</p> <div class="credits"> <p class="dwt_author">Martin, Raleigh L.; Jerolmack, Douglas J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">211</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60190239"> <span id="translatedtitle">The extraction of bitumen from western oil <span class="hlt">sands</span>: Volume 2. Final report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The program is composed of 20 projects, of which 17 are laboratory bench or laboratory pilot scale processes or computer process simulations that are performed in existing facilities on the University of Utah campus in north-east Salt Lake City. These tasks are: (1) coupled fluidized-<span class="hlt">bed</span> bitumen recovery and coked <span class="hlt">sand</span> combustion; (2) water-based recovery of bitumen; (3) oil <span class="hlt">sand</span> pyrolysis</p> <div class="credits"> <p class="dwt_author">A. G. Oblad; D. A. Dahlstrom; M. D. Deo; J. V. Fletcher; F. V. Hanson; J. D. Miller; J. D. Seader</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">212</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60697588"> <span id="translatedtitle">The extraction of bitumen from western oil <span class="hlt">sands</span>: Volume 1. Final report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The program is composed of 20 projects, of which 17 are laboratory bench or laboratory pilot scale processes or computer process simulations that are performed in existing facilities on the University of Utah campus in north-east Salt Lake City. These tasks are: (1) coupled fluidized-<span class="hlt">bed</span> bitumen recovery and coked <span class="hlt">sand</span> combustion; (2) water-based recovery of bitumen; (3) oil <span class="hlt">sand</span> pyrolysis</p> <div class="credits"> <p class="dwt_author">A. G. Oblad; D. A. Dahlstrom; M. D. Deo; J. V. Fletcher; F. V. Hanson; J. D. Miller; J. D. Seader</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">213</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.energy-based.nrct.go.th/Article/Ts-3%20emission%20performance%20and%20combustion%20efficiency%20of%20a%20conical%20fluidized-bed%20combustor%20firing%20various%20biomass%20fuels.pdf"> <span id="translatedtitle">Emissio nperformanc ean dcombustio nefficienc yo fa conical fluidized-<span class="hlt">bed</span> combustor firing various biomass fuels</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper summarizes the results of an experimental study on combustion of three distinct biomass fuels (sawdust, rice husk and pre-dried sugar cane bagasse) in a single fluidized-<span class="hlt">bed</span> combustor (FBC) with a conical <span class="hlt">bed</span> using silica <span class="hlt">sand</span> as the inert <span class="hlt">bed</span> ma- terial. Temperature, CO, NO and O2 concentrations along the combustor height as well as in flue (stack) gas</p> <div class="credits"> <p class="dwt_author">W. Permchar</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">214</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/35553729"> <span id="translatedtitle">Emission performance and combustion efficiency of a conical fluidized-<span class="hlt">bed</span> combustor firing various biomass fuels</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper summarizes the results of an experimental study on combustion of three distinct biomass fuels (sawdust, rice husk and pre-dried sugar cane bagasse) in a single fluidized-<span class="hlt">bed</span> combustor (FBC) with a conical <span class="hlt">bed</span> using silica <span class="hlt">sand</span> as the inert <span class="hlt">bed</span> material. Temperature, CO, NO and O2 concentrations along the combustor height as well as in flue (stack) gas were</p> <div class="credits"> <p class="dwt_author">W. Permchart; V. I. Kouprianov</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">215</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://facstaff.gpc.edu/~janderso/historic/labman/sievean.htm"> <span id="translatedtitle"><span class="hlt">Sand</span> Sieve Analysis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">John R. Anderson of Georgia Perimeter College has authored this lab experiment on grain size sorting in which students learn about performing a sieve analysis of <span class="hlt">sand</span> and produce various graphs to represent the data collected. Included are equations for making the graphs and basic information on the importance of sieve analysis and the four useful statistical measurements used to make the graphs. This is a great resource to either the creation or enhancement of an instructors curriculum on this topic.</p> <div class="credits"> <p class="dwt_author">Anderson, John</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-21</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">216</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/347674"> <span id="translatedtitle">Effects of stratification in a fluidized <span class="hlt">bed</span> bioreactor during treatment of metalworking wastewater</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">During wastewater treatment, biofilm-coated <span class="hlt">sand</span> particles stratified in a fluidized <span class="hlt">bed</span> bioreactor (FBB); particles coated by thicker biofilm segregated toward the top of the <span class="hlt">bed</span>. Stratification was so well developed that at least two co-existing regions of significantly different mean biofilm thickness were visually distinct within the operating FBB. The observed stratification is attributed to differences in forces of drag, buoyancy, shear, and collisional impact, as well as differences of collision rate within the different regions. Particles with thick biofilm near the top of the <span class="hlt">bed</span> consumed substrate at significantly lower rates per unit biomass than particles with thin biofilm near the bottom of the <span class="hlt">bed</span>, thereby suggesting that substrate mass-transfer resistance through biofilm may limit biodegradation rates in the upper portion of the FBB. Large agglomerates of biomass floc and <span class="hlt">sand</span>, which formed at the top of the fluidized <span class="hlt">bed</span>, and <span class="hlt">sand</span> particles with thick biofilm were susceptible to washout from the FBB, causing operational and treatment instability. Radial injection of supplemental liquid feed near the top of the <span class="hlt">bed</span> increased shear and mixing, thereby preventing formation and washout of agglomerates and thickly coated <span class="hlt">sand</span> particles. Supplemental liquid injection caused the mean specific biomass loading on the <span class="hlt">sand</span> to increase and also increased the total biomass inventory in the FBB. Rates of biodegradation in the FBB appeared to be limited by penetration of substrates into the biofilm and absorption of oxygen from air into the wastewater.</p> <div class="credits"> <p class="dwt_author">Schreyer, H.B.; Coughlin, R.W. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemical Engineering] [Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemical Engineering</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-04-20</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">217</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=39452"> <span id="translatedtitle">CADMIUM EFFECTS ON THE NITROGEN FIXATION SYSTEM OF <span class="hlt">RED</span> ALDER</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary"><span class="hlt">Red</span> alder (Alnus rubra) was grown in <span class="hlt">sand</span> culture in the greenhouse to obtain data on the effects of cadmium (Cd) on a symbiotic nitrogen (N) fixation system which contributes to the fertility of forest soils. Treatment of <span class="hlt">red</span> alder seedlings for 11 weeks with 0.545 to 136 microm...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">218</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/864177"> <span id="translatedtitle">Hybrid fluidized <span class="hlt">bed</span> combuster</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A first atmospheric bubbling fluidized <span class="hlt">bed</span> furnace is combined with a second turbulent, circulating fluidized <span class="hlt">bed</span> furnace to produce heat efficiently from crushed solid fuel. The <span class="hlt">bed</span> of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first <span class="hlt">bed</span>, and elutriated solids extracted from the flu gases of the first <span class="hlt">bed</span>. 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 <span class="hlt">bed</span>.</p> <div class="credits"> <p class="dwt_author">Kantesaria, Prabhudas P. (Windsor, CT); Matthews, Francis T. (Poquonock, CT)</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">219</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pac.dfo-mpo.gc.ca/fm-gp/contamination/biotox/index-eng.htm"> <span id="translatedtitle"><span class="hlt">Red</span> Tides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This comprehensive website answers questions such as: what is <span class="hlt">red</span> tide, where are they found, why do they occur, how do they affect marine organisms, how do they affect humans, how are shellfish tested for the toxin, and what is being done to remediate the <span class="hlt">red</span> tide problem. The site features color pictures and black and white maps.</p> <div class="credits"> <p class="dwt_author">Communications Directorate, Department O.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">220</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004APS..APR.A1002S"> <span id="translatedtitle">Spontaneous Emergence of Order in Vibrated <span class="hlt">Sand</span>*</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Granular media such as <span class="hlt">sand</span>, pharmaceuticals, cereal, cosmetics, and asteroids are involved in many processes, yet granular media remain less well understood than fluids and solids. Vertically oscillating granular layers provide a test <span class="hlt">bed</span> for theory and modeling of granular dynamics. Experiments on vertically oscillating granular layers have revealed a variety of spatial patterns that emerge spontaneously as a function of the container acceleration amplitude and frequency: stripes, squares, hexagons, spirals, and oscillons (localized structures). Molecular dynamics simulations yield results in quantitative accord with laboratory observations. Since the gradients of density and velocity are large over a particle mean free path, the applicability of continuum theory has been questionable. However, hydrodynamic equations proposed for dissipative particles yield results in surprising qualitative accord with the laboratory observations. *Work in collaboration with C. Bizon, D. Goldman, W.D. McCormick, S.J. Moon, E. Rericha, M. Shattuck, and J. Swift. Supported by DOE.</p> <div class="credits"> <p class="dwt_author">Swinney, Harry L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-05-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_10");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">221</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.life.uiuc.edu/hanks/pdfs/Rust%20et%20al%201983.pdf"> <span id="translatedtitle">ACULEATA HYMENOPTERA OF <span class="hlt">SAND</span> MOUNTAIN AND BLOW <span class="hlt">SAND</span> MOUNTAINS, NEVADA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">vegetation was Atriplex con fertifolia (Torr. & Frem.), Tetradymia tetra meres (Blake), Chrysothamnus viscidiflorus (Hookl), Astragalus lentiginousus Dougl., and Psoralea lanceolata (Pursh.), and at <span class="hlt">Sand</span> Mountain</p> <div class="credits"> <p class="dwt_author">Hanks, Lawrence M.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">222</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70012085"> <span id="translatedtitle">Size distribution of Amazon River <span class="hlt">bed</span> sediment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The first recorded observations of <span class="hlt">bed</span> 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 <span class="hlt">bed</span> material of the river to be mostly <span class="hlt">sand</span> and fine gravel. Oltman and Ames took samples at a few locations in 1963 and 1964, and reported the <span class="hlt">bed</span> material at O??bidos, Brazil, to be fine <span class="hlt">sands</span>, 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.</p> <div class="credits"> <p class="dwt_author">Nordin, C.F.; Meade, R.H.; Curtis, W.F.; Bosio, N.J.; Landim, P.M.B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">223</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/7039902"> <span id="translatedtitle">Reconnaissance examination of selected oil-<span class="hlt">sand</span> outcrops in Wyoming</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Numerous surface occurrences of oil <span class="hlt">sands</span> and oil seeps have been reported in the geologic literature for Wyoming. Seventy-eight reported occurrences are listed in Wyoming Geological Survey Open-File Report 82-5. Most of the listed deposits are taken from old references with vague descriptions and locations. Field reconnaissance examinations of selected oil-<span class="hlt">sand</span> occurrences were conducted to describe them better and to assess their potential economic importance. A reconnaissance geologic map of each examined deposit was constructed, and the deposits were sampled and described. Ten occurrences were described during the 1984 and 1985 field seasons. The oil-<span class="hlt">sand</span> occurrences were all sandstone reservoirs ranging from Pennsylvanian to Tertiary. Based on these reconnaissance examinations, only three occurrences appeared to be potentially significant. The Rattlesnake Hills occurrence, west of Casper, is an asymmetrical anticline with oil-impregnated <span class="hlt">sands</span> in the Mesaverde Formation, Frontier Formation, and, most extensively, the Muddy Sandstone. Other formations in the structure contain minor amounts of oil staining. The Muddy Creek occurrence, southwest of Rawlins, contains oil-impregnated sandstones in the lower Wasatch Formation. This stratigraphically controlled trap dips to the west into the Washakie basin. The Conant Creek occurrence, southeast of Riverton, includes stratigraphically controlled oil <span class="hlt">sands</span> in the relatively flat Wagon <span class="hlt">Bed</span> Formation.</p> <div class="credits"> <p class="dwt_author">Ver Ploeg, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">224</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19880153"> <span id="translatedtitle">Laboratory singing <span class="hlt">sand</span> avalanches.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Some desert <span class="hlt">sand</span> dunes have the peculiar ability to emit a loud sound up to 110 dB, with a well-defined frequency: this phenomenon, known since early travelers (Darwin, Marco Polo, etc.), has been called the song of dunes. But only in late 19th century scientific observations were made, showing three important characteristics of singing dunes: first, not all dunes sing, but all the singing dunes are composed of dry and well-sorted <span class="hlt">sand</span>; second, this sound occurs spontaneously during avalanches on a slip face; third this is not the only way to produce sound with this <span class="hlt">sand</span>. More recent field observations have shown that during avalanches, the sound frequency does not depend on the dune size or shape, but on the grain diameter only, and scales as the square root of g/d--with g the gravity and d the diameter of the grains--explaining why all the singing dunes in the same vicinity sing at the same frequency. We have been able to reproduce these singing avalanches in laboratory on a hard plate, which made possible to study them more accurately than on the field. Signals of accelerometers at the flowing surface of the avalanche are compared to signals of microphones placed above, and it evidences a very strong vibration of the flowing layer at the same frequency as on the field, responsible for the emission of sound. Moreover, other characteristics of the booming dunes are reproduced and analyzed, such as a threshold under which no sound is produced, or beats in the sound that appears when the flow is too large. Finally, the size of the coherence zones emitting sound has been measured and discussed. PMID:19880153</p> <div class="credits"> <p class="dwt_author">Dagois-Bohy, Simon; Ngo, Sandrine; du Pont, Sylvain Courrech; Douady, Stéphane</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">225</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1995WRR....31.2087W"> <span id="translatedtitle">Unequal Mobility of Gravel and <span class="hlt">Sand</span> in Weakly Bimodal River Sediments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Bed</span> load was trapped during flood events over a 20-month period at the lower end of the Allt Dubhaig, a small river in Scotland with rapid downstream fining of gravel <span class="hlt">bed</span> material on a slowly aggrading concave long profile. The channel <span class="hlt">bed</span> near the trap is predominantly gravel with a secondary <span class="hlt">sand</span> mode. Total transport in each event depended mainly on peak shear stress, rather than duration over a threshold. <span class="hlt">Bed</span> load was mainly <span class="hlt">sand</span> in smaller events, bimodal in intermediate events, and mainly gravel in the biggest floods. Mean and maximum grain diameter both increased with peak shear stress, but in different ways. Analysis of fractional transport rates and maximum grain size in relation to peak shear stress suggests that gravel transport is slightly size selective but <span class="hlt">sand</span> transport is close to equal mobility. The slight selectivity in gravel transport is consistent with previous field studies of near-equilibrium unimodal <span class="hlt">beds</span> and supports assumptions made in the numerical model of Hoey and Ferguson (1994), which successfully simulates the observed amount of downstream fining over the 2.5-km upstream of the <span class="hlt">bed</span> load trap.</p> <div class="credits"> <p class="dwt_author">Wathen, Simon J.; Ferguson, Robert I.; Hoey, Trevor B.; Werritty, Alan</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">226</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/220129"> <span id="translatedtitle">Simulation on hydraulic scale model of <span class="hlt">sand</span> and silt transport in the lower Mississippi River</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Since many years river sediment transport of <span class="hlt">sand</span> and silt has been successfully reproduced on scale models by using light density materials. Compared to geometric distortion of the model scales where the secondary currents are not correctly reproduced, the sediment density distortion enables a more precise simulation of total sediment transport process (<span class="hlt">bed</span> load and suspended load). The paper discussed among other model studies carried out with light density material the model study of the old River Control outflow channel improvement and bank stabilization studies using a 1 to 100 scale physical model. Some of the aspects of the channel <span class="hlt">bed</span> and bank evolution could not have been simulated if the model <span class="hlt">bed</span> material behaved always as <span class="hlt">bed</span> load. Because in a river or channel carrying <span class="hlt">sand</span> and silt, depending on the flow turbulence the same material at times my represent the <span class="hlt">bed</span> load and at another time the suspended load. On a scale model only certain type of light density material is capable of such representation. Various model studies to date enables us to confirm that, 1 to 100 scale model using treated sawdust of given grain size distribution and specific weight, reproduces correctly the river <span class="hlt">sand</span> and silt transport in the Old River Control area of the Lower Mississippi River. The paper also discusses the use of a midget echosounder system for quick and precise hydroelectric survey of the model <span class="hlt">bed</span> and bank morphology variations and evaluation of scour and deposit volumes after running a given flood hydrograph.</p> <div class="credits"> <p class="dwt_author">Alam, S. [Hydropower and River Engineering, Le Beausset (France); Laukhuff, R.L. Jr. [Louisiana Hydroelectric, Vidalia, LA (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-12-31</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">227</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/sciencecinema/biblio/1134568"> <span id="translatedtitle"><span class="hlt">Red</span> Sky with <span class="hlt">Red</span> Mesa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/sciencecinema/">ScienceCinema</a></p> <p class="result-summary">The <span class="hlt">Red</span> Sky/<span class="hlt">Red</span> Mesa supercomputing platform dramatically reduces the time required to simulate complex fuel models, from 4-6 months to just 4 weeks, allowing researchers to accelerate the pace at which they can address these complex problems. Its speed also reduces the need for laboratory and field testing, allowing for energy reduction far beyond data center walls.</p> <div class="credits"> <p class="dwt_author">None</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">228</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009EGUGA..1114066K"> <span id="translatedtitle">Phosphorus accummulation in reed <span class="hlt">bed</span> treatment filter</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Introduction Constructed wetlands are well known method for alternative wastewater treatment in rural areas in Poland. There are mainly used as a biological treatment step of domestic wastewater. The most popular are subsurface flow constructed wetlands (reed <span class="hlt">bed</span> systems) with <span class="hlt">bed</span> filled with site soil (mainly clayey <span class="hlt">sand</span> or sandy clay). Over 30 such plants with daily flow above 5 m3 per day is operated in Poland. Object and goal of research Many researches have been made on estimation constructed wetlands treatment efficiency, however there are mostly concentrated on inlet outlet concentration compartments. In this study preliminary results of phosphorus accumulation in the <span class="hlt">bed</span> of horizontal subsurface flow constructed wetland are presented. Monitored plant treats wastewater from 150 inhabitants in the volume of 14 m3 d-1 at average and is under operation from December 1998. The goal of research was to asses the distribution of phosphorus in the wetland <span class="hlt">bed</span> after 8 years of treatment of domestic wastewater. Obtained results are shown on the background of organic matter (TOC) distribution. The methods applied The <span class="hlt">bed</span> of the constructed wetland (30 m width and 33 m length) was divided by net of 20 points. In every point two soil samples, one from the depth of 0-10 cm and one from the depth of 20-30 cm, were collected. The samples were analyzed for organic matter and total phosphorus content. Investigation findings The results showed variation of measured indexes on the length and depth of treatment <span class="hlt">bed</span>. In generally, the highest accumulation occurred near the inlet zone of wetland. The relation is rather clear in case of organic matter, but in case of phosphorus high contents were also observed at the outlet zone of wetland. Higher organic matter concentrations were observed in deeper layer (20-30 cm) than in upper layer (0-10 cm) of the <span class="hlt">bed</span>.</p> <div class="credits"> <p class="dwt_author">Karczmarczyk, A.; Bary?a, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">229</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000APS..DFD.AH005S"> <span id="translatedtitle">Yield stress transition in gas fluidized <span class="hlt">sand</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Gas fluidized powders can take on three distinct states. I: Solid like for low gas flow rates. II: At intermediate flow rates, the <span class="hlt">bed</span> expands and drastically reduces its yield stress, i.e. quicksand which cannot support the weight of solid objects. III: At high flow rates rising gas bubbles churn the <span class="hlt">sand</span> grains violently. We have measured that the transition from regime I to II does not occur simultaneously for the entire column, but rather as a well defined front which sweeps through the column as a function of gas flow rate. Earlier measurements sensed this front by measuring the depth to which a brass sphere would sink in the liquid phase. We have supplemented this with careful measurements of the vertical gas pressure gradient throughout the column. The pressure profile shows a distinct change in the gradient at a height which correlates well with results from the sinking sphere measurement. From the pressure gradient we calculate the local gas permeability of the <span class="hlt">sand</span>, which is related to the grain density, which can be measured with an accuracy of better than 1 part in 100. We thank the NSF-REU program for partial support of this research.</p> <div class="credits"> <p class="dwt_author">Stoker, David; Poker, Jennifer; Savrin, Tamara; Rutgers, Maarten</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">230</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=feet&id=EJ938144"> <span id="translatedtitle">Making a <span class="hlt">Bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">The origins of this paper lay in making <span class="hlt">beds</span> by putting pieces of plywood on a frame: If <span class="hlt">beds</span> 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 <span class="hlt">beds</span>)? The problem is of course generalized.</p> <div class="credits"> <p class="dwt_author">Wexler, Anthony; Stein, Sherman</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">231</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/357891"> <span id="translatedtitle">The combustion rate of volatiles in a fluidized <span class="hlt">bed</span> combustor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The combustion rate of coal volatiles within the dense phase is controlled by the rate of mixing with oxygen from the fluidizing air. Multiple discrete diffusion flame and plume models for volatiles combustion assume that this rate is determined by a radial dispersion coefficient, which characterizes the lateral mixing rate at the boundary between a plume of volatiles rising through the <span class="hlt">bed</span> and the adjacent oxygen-containing region. The radial dispersion of tracer gas has been resolved into plume meandering and turbulent components, and the combustion rate of volatiles was assumed to be controlled by the turbulent dispersion coefficient. This paper investigates the applicability of the plume model with these turbulent dispersion coefficients to the prediction of the combustion rate of volatiles within the <span class="hlt">bed</span>. Tracer gas and combustion experiments were performed at 850--900 C in the same fluidized <span class="hlt">bed</span>. Nitrogen tracer gas and volatiles (simulated by propane) were injected through a single injector at the base of the air-fluidized <span class="hlt">bed</span>. Time-resolved oxygen concentrations were measured in-situ by a Zirconia oxygen sensor for resolution into the radial dispersion components. The radial dispersion coefficient for volatiles combustion rate was deduced by fitting plume model predictions to measurements of the heat release rate within the <span class="hlt">bed</span>. The turbulent radial dispersion was compared to the radial dispersion for combustion. Within experimental error, the turbulent radial dispersion coefficient could be used in the plume model to predict the in-<span class="hlt">bed</span> combustion rate of volatiles only for the 1.55mm <span class="hlt">sand</span> particles. For the 0.78 and 0.55mm <span class="hlt">sand</span> particles, the turbulent dispersion coefficient was substantially lower than the combustion dispersion coefficient. This was attributed to the occurrence of clouded bubbles in the <span class="hlt">beds</span> of smaller <span class="hlt">sand</span> particles, to which the plume model cannot be applied. For small particle sizes, a different volatiles combustion model needs to be developed.</p> <div class="credits"> <p class="dwt_author">Stubington, J.F.; Clough, S.J. [Univ. of New South Wales, Sydney, New South Wales (Australia)</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-12-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">232</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://nccam.nih.gov/health/redclover/ataglance.htm"> <span id="translatedtitle"><span class="hlt">Red</span> Clover</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://medlineplus.gov/">MedlinePLUS</a></p> <p class="result-summary">Skip to main content U.S. Department of Health & Human Services National Institutes of Health Search NIH…Turning ... body, including how <span class="hlt">red</span> clover isoflavones may affect human prostate cells and the safety and effectiveness of ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">233</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17616873"> <span id="translatedtitle">Assessment of metals in <span class="hlt">bed</span> and suspended sediments in tributaries of the Lower Athabasca River.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Several oil <span class="hlt">sands</span> mines and refineries are currently recovering oil from the Athabasca River region near Fort McMurray, Alberta. Planning and construction of additional oil <span class="hlt">sands</span> mines are in various stages of completion. Due to environmental concerns for aquatic life in areas downstream from current and future oil <span class="hlt">sands</span> activities, surveys were conducted between 1998 and 2000 to determine whether the quality of water and sediments in tributaries of the Athabasca River are affected by flowing through reaches with exposure to natural oil <span class="hlt">sand</span> deposits. This paper presents the results for metals in <span class="hlt">bed</span> and suspended sediments collected from the Mackay, Steepbank, and Ells rivers during those surveys. The suspended sediments had a clay content (n = 7) ranging from 36.2% to 65.0%, while <span class="hlt">bed</span> sediments, which consisted of a predominant <span class="hlt">sand</span> fraction, had percent clay (n = 39) ranging from 0.0% to 38.1%. A Mann-Kendall non-parametric analysis to assess the longitudinal trend of the metals in the <span class="hlt">bed</span> sediments found no significant (alpha = 0.05) downstream trend in the Mackay or Steepbank rivers; however, the Ells River displayed a generally decreasing tend from upstream to downstream. The results provide no indication that metal concentrations in the <span class="hlt">bed</span> sediments and/or suspended sediments of the Mackay, Steepbank, and Ells rivers increase significantly as the three tributaries flow through reaches that have natural oil <span class="hlt">sand</span> exposures (McMurray Formation). PMID:17616873</p> <div class="credits"> <p class="dwt_author">Conly, F M; Crosley, R W; Headley, J V; Quagraine, E K</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">234</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40283450"> <span id="translatedtitle">Plume persistence caused by back diffusion from thin clay layers in a <span class="hlt">sand</span> aquifer following TCE source-zone hydraulic isolation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper concludes that back diffusion from one or a few thin clayey <span class="hlt">beds</span> in a <span class="hlt">sand</span> aquifer can cause contaminant persistence above MCLs in a <span class="hlt">sand</span> aquifer long after the source zone initially causing the plume is isolated or removed. This conclusion is based on an intensive case study of a TCE contaminated site in Florida, with the processes</p> <div class="credits"> <p class="dwt_author">Beth L. Parker; Steven W. Chapman; Martin A. Guilbeault</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">235</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010pot..book..953P"> <span id="translatedtitle">Destruction of N2O over Different <span class="hlt">Bed</span> Materials</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Since under fluidized <span class="hlt">bed</span> conditions N2O is produced as a by product of the De-NOx process, the thermal decomposition of N2O was investigated under conditions relevant to those in FBC installations. Laboratory experiments were made in a current of nitrogen using a fixed <span class="hlt">bed</span> of pure quartz <span class="hlt">sand</span> or <span class="hlt">sand</span> with 10% (wt.) of the solids tested, CaO and Fe2O3. With a <span class="hlt">sand</span> <span class="hlt">bed</span> the decomposition was slightly faster than in the empty reactor and the reaction was first order with respect to [N2O]. Both fresh CaO and Fe2O3 strongly catalysed N2O decomposition. Their effectiveness diminished after they were heated to temperatures typical for FBC, but they still retained appreciable activity. This activity went down with increasing particle size. The flue gas components investigated were O2, water vapour and CO2. Their presence appeared to interfere with N2O decomposition and increased with the concentration of the additive. The observations indicated that this could only be due to heterogeneous effects. Thus the effects of the <span class="hlt">bed</span> solids and of the gas phase components are opposed. The effects associated with N2O decomposition have proved to be surprisingly complex and instead of supplying simple answers, this work uncovered more problems.</p> <div class="credits"> <p class="dwt_author">Pilawska, M.; Zhang, H.; Hout, X. S.; Liu, Q.; Lu, J. F.; Yue, G. X.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">236</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JGRF..114.2005N"> <span id="translatedtitle">Response of <span class="hlt">bed</span> surface patchiness to reductions in sediment supply</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">River <span class="hlt">beds</span> are often arranged into patches of similar grain size and sorting. Patches can be distinguished into "free patches," which are zones of sorted material that move freely, such as <span class="hlt">bed</span> load sheets; "forced patches," which are areas of sorting forced by topographic controls; and "fixed patches" of <span class="hlt">bed</span> material rendered immobile through localized coarsening that remain fairly persistent through time. Two sets of flume experiments (one using bimodal, <span class="hlt">sand</span>-rich sediment and the other using unimodal, <span class="hlt">sand</span>-free sediment) are used to explore how fixed and free patches respond to stepwise reductions in sediment supply. At high sediment supply, migrating <span class="hlt">bed</span> load sheets formed even in unimodal, <span class="hlt">sand</span>-free sediment, yet grain interactions visibly played a central role in their formation. In both sets of experiments, reductions in supply led to the development of fixed coarse patches, which expanded at the expense of finer, more mobile patches, narrowing the zone of active <span class="hlt">bed</span> load transport and leading to the eventual disappearance of migrating <span class="hlt">bed</span> load sheets. Reductions in sediment supply decreased the migration rate of <span class="hlt">bed</span> load sheets and increased the spacing between successive sheets. One-dimensional morphodynamic models of river channel <span class="hlt">beds</span> generally are not designed to capture the observed variability, but should be capable of capturing the time-averaged character of the channel. When applied to our experiments, a 1-D morphodynamic model (RTe-bookAgDegNormGravMixPW.xls) predicted the <span class="hlt">bed</span> load flux well, but overpredicted slope changes and was unable to predict the substantial variability in <span class="hlt">bed</span> load flux (and load grain size) because of the migration of mobile patches. Our results suggest that (1) the distribution of free and fixed patches is primarily a function of sediment supply, (2) the dynamics of <span class="hlt">bed</span> load sheets are primarily scaled by sediment supply, (3) channels with reduced sediment supply may inherently be unable to transport sediment uniformly across their width, and (4) cross-stream variability in shear stress and grain size can produce potentially large errors in width-averaged sediment flux calculations.</p> <div class="credits"> <p class="dwt_author">Nelson, Peter A.; Venditti, Jeremy G.; Dietrich, William E.; Kirchner, James W.; Ikeda, Hiroshi; Iseya, Fujiko; Sklar, Leonard S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">237</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hal.archives-ouvertes.fr/docs/00/50/85/27/PDF/LY1993-PUB00005598.pdf"> <span id="translatedtitle">WASTEWATER TREATMENT OVER <span class="hlt">SAND</span> COLUMNS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">93/0096 WASTEWATER TREATMENT OVER <span class="hlt">SAND</span> COLUMNS TREATMENT YIELDS, LOCALISATION OF THE BIOMASS Domestic wastewater treatment by infiltration-percolation is a process that becomming common in France, a greater depth for desinfection purposes. KEYWORDS Wastewater treatment, Infiltration-percolation. <span class="hlt">Sand</span></p> <div class="credits"> <p class="dwt_author">Paris-Sud XI, Université de</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">238</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/19857849"> <span id="translatedtitle">Non-aeolian <span class="hlt">sand</span> ripples</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">By examining the initial stages of the impact of a granular jet on a flat horizontal solid surface we evidenced the existence of oscillatory <span class="hlt">sand</span> fronts. These oscillations give rise to a novel mechanism for the formation of ripples on <span class="hlt">sand</span> surfaces. We here show that as the front advances, its slope changes periodically in time, leaving behind a succession</p> <div class="credits"> <p class="dwt_author">J. F. Boudet; Y. Amarouchene; B. Bonnier; H. Kellay</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">239</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21168991"> <span id="translatedtitle">Combustion of hydrogen in a bubbling fluidized <span class="hlt">bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The combustion of hydrogen in a hot, bubbling <span class="hlt">bed</span> of quartz <span class="hlt">sand</span> fluidized by air has been studied for the first time, by injecting hydrogen just above the distributor, via six horizontal fine tubes of Cr/Ni. Overall the fluidizing gas was oxygen-rich, with the composition varying from nearly stoichiometric to very lean mixtures. With the <span class="hlt">bed</span> initially fluidized at room temperature, combustion (after ignition by a pilot flame) occurs in a premixed flame sitting on top of the <span class="hlt">bed</span>. When the <span class="hlt">sand</span> warms up, combustion becomes explosive in bubbles leaving the <span class="hlt">bed</span>, exactly as with a hydrocarbon as fuel. However, in contrast to hydrocarbons, it is clear that when the <span class="hlt">bed</span> reaches 500-600 C, heat is produced both above the top of the <span class="hlt">bed</span> (because of H{sub 2} bypassing the <span class="hlt">bed</span>) and very low down in the <span class="hlt">bed</span>. In fact, with hydrogen as fuel, the location of where bubbles ignite descends abruptly to low in the <span class="hlt">sand</span>; furthermore, the descent occurs at {proportional_to}500 C, which is {proportional_to}100 K below the ignition temperature predicted by well-established kinetic models. However, the kinetic models do reproduce the observations, if it is assumed that the Cr/Ni hypodermic tubes, through which the fuel was injected, exert a catalytic effect, producing free H atoms, which then give rise to HO{sub 2} radicals. In this situation, kinetic modeling indicates that bubbles ignite when they become sufficiently large and few enough to have a lifetime (i.e. the interval between their collisions) longer than the ignition delay for the temperature of the <span class="hlt">sand</span>. The amounts of NO found in the off-gases were at a maximum (24 ppm), when the <span class="hlt">bed</span> was at {proportional_to}500 C for {lambda}=[O{sub 2}]/[O{sub 2}]{sub stoich}=1.05. The variations of [NO] with [air]/[H{sub 2}] and also temperature indicate that NO is produced, at least partly, via the intermediate N{sub 2}H. In addition, the air-afterglow emission of green light (from NO+O{yields}NO{sub 2}+h{nu}) was observed in the freeboard, indicating the presence there of both NO and free atoms of oxygen for 1.05<{lambda}<1.1. (author)</p> <div class="credits"> <p class="dwt_author">Baron, J.; Bulewicz, E.M.; Zukowski, W. [Faculty of Chemical Engineering and Technology, Cracow University of Technology, ul. Warszawska 24, 31 - 155 Krakow (Poland); Kandefer, S.; Pilawska, M. [Faculty of Environmental Engineering, Cracow University of Technology, ul. Warszawska 24, 31 - 155 Krakow (Poland); Hayhurst, A.N. [Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom)</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">240</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/45201355"> <span id="translatedtitle">Channel Morphology Response to Selective Wood Removals in a <span class="hlt">Sand</span>-Laden Wisconsin Trout Stream</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Large <span class="hlt">sand</span> <span class="hlt">bed</span> loads in trout stream headwaters can limit salmonid spawning habitat and reproductive success. This phenomenon has been observed in many northern Wisconsin watersheds, where historic logging practices are the likely source of the sediment loading. Presently, sediment transport is limited by abundant woody debris, causing channels to aggrade and bury gravels. We evaluated the impacts of a</p> <div class="credits"> <p class="dwt_author">Joshua D. Dumke; Thomas R. Hrabik; Valerie J. Brady; Karen B. Gran; Ronald R. Regal; Michael J. Seider</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_11");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">241</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=https://www.shom.fr/fr_page/fr_act_geo/abstract2000/TPhenning2.pdf"> <span id="translatedtitle">On the Behaviour of Hydrodynamic Processes due to the Presence of Submarine <span class="hlt">Sand</span> Waves</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Radar signatures of the sea <span class="hlt">bed</span> in coastal waters show that submarine <span class="hlt">sand</span> waves superimposed on sandbanks or tidal current ridges change their orientation and character abruptly at the crest of the ridge. These observations were made when studying air- and spaceborne radar images of the southern North Sea (McLeish et al., 1981). Similar phenomena were already reported by analysing</p> <div class="credits"> <p class="dwt_author">Ingo HENNINGS; Blandine LURIN; C. VERNEMMEN</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">242</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nnin.org/education-training/k-12-teachers/nanotechnology-curriculum-materials/exploring-properties-magic-sand"> <span id="translatedtitle">Exploring Magic <span class="hlt">Sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Nanotechnology is an area of science and engineering that occurs at the atomic and molecular level. This is certainly a difficult concept to grasp. This website, presented by The National Infrastructure Network, highlights many critical concepts to understanding this smaller scale. By using a product called "Magic <span class="hlt">Sand</span>," the activity "will explore how the properties of a substance at the molecular level affects the way that it reacts and behaves." Additionally, students will explore nanotechnology as an emerging and interdisciplinary field. The experiment will show students how developments in the field can improve devices, materials, and structures we use on a daily basis. A student and teacher guide is provided with the lab. Overall, this is a great exercise for any science classroom interested in the workings of nanotechnology.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-16</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">243</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15..402R"> <span id="translatedtitle">Atlas of Dutch drift <span class="hlt">sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Netherlands is well known for its aeolian landscapes. Frequent storms during the High Middle Ages (1000-1300 AD) reactivated Pleistocene coversands and river dunes and are responsible for the formation of the Holocene drift <span class="hlt">sands</span> at a scale which is unique for Europe. A hypothesized relationship with farmer practices for making plaggensoils has recently been refuted, because drift <span class="hlt">sand</span> formation began centuries earlier. The coastal dune belt with their parabolic dunes dates from the same period as the drift <span class="hlt">sand</span>. An estimate of the extent of drift <span class="hlt">sands</span> can be made from soil maps: drift <span class="hlt">sands</span> are too young to show much profile development (Regosols). With this method Koster estimated the maximum extent of Holocene drift <span class="hlt">sands</span> in the Netherlands to be about 800 km2 (Koster 2005). Laser altimetry allows a more precise estimate of the total surface affected by wind from the characteristic relief patterns produced by the Holocene wind, which is different from the smooth surface of cover <span class="hlt">sand</span> deposits. Laser altimetry has been used before to investigate the mechanism of drift <span class="hlt">sand</span> formation (Jungerius & Riksen 2010). Most of the surface affected by wind is not active anymore, but the tell-tale rough surface survived ages of different landuse. The total affected surface amounts to 825 km2. It is noteworthy that both methods give comparable results. We recorded a total number of 367 of affected areas of varying shapes, ranging in size from 1.6 ha to a large complex of drif <span class="hlt">sands</span> of 7,119.5 ha. As is to be expected from their mode of origin, most occurrences are associated with cover <span class="hlt">sands</span>, and with river dunes along the river Meuse and smaller rivers in other parts of the country. Particularly the final phases of cover <span class="hlt">sand</span> and river dunes that show more relief as parabolic dunes were affected. There are also small aeolian deposits at the lee side blown from fallow agricultural fields but they are (sub)recent. Most of the relief is irregular, but the larger occurrences associated with push moraines show that drift <span class="hlt">sand</span> occurs in elongated cells that are parallel to the prevailing SW wind. Their internal structure reflects the characteristic sequence of geomorphological processes: deflation dominant in the south-west, transport and accumulation towards the north east. Literature • Jungerius, P.D., Riksen, M.J.P.M., 2010. Contribution of laser altimetry images to the geomorphology of the Late Holocene inland drift <span class="hlt">sands</span> of the European <span class="hlt">Sand</span> Belt. Baltica 23, 1: 59-70. • Koster EA. 2005. Aeolian environments. In The physical Geography of Western Europe, Koster EA (ed). Oxford Regional Environments, Oxford University Press;139-160.</p> <div class="credits"> <p class="dwt_author">Riksen, Michel; Jungerius, Pieter</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">244</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA04859&hterms=water+policy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwater%2Bpolicy"> <span id="translatedtitle"><span class="hlt">Sand</span> and Water</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> [figure removed for brevity, see original site] <p/>Released 7 November 2003<p/>This image shows a relatively small crater (35 km across) in the heavily cratered terrain of the southern highlands. At the midlatitudes, this area is known both for its water-formed gullies and its <span class="hlt">sand</span> dunes. This crater shows spectacular examples of both. In fact, the gullies running down the northern edge of the crater made it to the cover of Science magazine on June 30, 2000. The large dark spot in the floor of the crater is <span class="hlt">sand</span> that has accumulated into one large dune with a single curvilinear crest.<p/>Image information: VIS instrument. Latitude -54.9, Longitude 17.5 East (342.5 West). 19 meter/pixel resolution.<p/>Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. <p/>NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">245</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48897661"> <span id="translatedtitle">Effects of <span class="hlt">bed</span> roughness on boundary layer mixing and mass flux across the sediment-water interface</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Fine-scale measurements of boundary layer flow and solute transport were conducted within a laboratory flume to determine how <span class="hlt">bed</span> topography influences mixing and mass transport at the sediment-water interface. Three different <span class="hlt">bed</span> topographies were examined, with roughness composed of <span class="hlt">sand</span>, gravel, or cobbles. Fluorescein dye, used as a dissolved tracer, was injected into the flow, and concentration and velocity were</p> <div class="credits"> <p class="dwt_author">M. A. Reidenbach; M. Limm; M. Hondzo; M. T. Stacey</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">246</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110023807&hterms=tar+sand&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtar%2Bsand"> <span id="translatedtitle">Model of Fluidized <span class="hlt">Bed</span> Containing Reacting Solids and Gases</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A mathematical model has been developed for describing the thermofluid dynamics of a dense, chemically reacting mixture of solid particles and gases. As used here, "dense" signifies having a large volume fraction of particles, as for example in a bubbling fluidized <span class="hlt">bed</span>. The model is intended especially for application to fluidized <span class="hlt">beds</span> that contain mixtures of carrier gases, biomass undergoing pyrolysis, and <span class="hlt">sand</span>. So far, the design of fluidized <span class="hlt">beds</span> and other gas/solid industrial processing equipment has been based on empirical correlations derived from laboratory- and pilot-scale units. The present mathematical model is a product of continuing efforts to develop a computational capability for optimizing the designs of fluidized <span class="hlt">beds</span> and related equipment on the basis of first principles. Such a capability could eliminate the need for expensive, time-consuming predesign testing.</p> <div class="credits"> <p class="dwt_author">Bellan, Josette; Lathouwers, Danny</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMEP44A..05M"> <span id="translatedtitle">Transient response of <span class="hlt">sand</span> bedforms to changes in flow</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Lowland rivers commonly experience discharge variability spanning more than an order of magnitude, producing correspondingly large changes in <span class="hlt">bed</span> morphology. However, field and lab studies indicate that bedform geometries lag changes in flow, producing hysteretic relationships between <span class="hlt">bed</span> morphology, roughness, and water discharge. The ability of bedforms to maintain equilibrium with hydrodynamic flow variability thus depends on the timescale of transient bedform adjustment to flow. Here, we present results of flume experiments carried out at the Saint Anthony Falls Laboratory, University of Minnesota, in which we continuously tracked adjustment of <span class="hlt">sand</span> bedform morphologies to abrupt changes in water discharge. We show how the timescale of bedform adjustment is driven by three primary factors: 1. directionality of adjustment, 2. preexisting bedform geometry, and 3. sediment flux. Directionality of adjustment (rising versus falling water discharge) determines whether bedforms grow quickly by irreversible merger (rising flows) or shrink slowly through secondary bedform cannibalization of relict larger bedforms (falling flows). Preexisting bedform geometry (height and length) determines the amount of <span class="hlt">bed</span> deformation required for adjustment to new equilibrium, and sediment flux determines the rate at which this change is affected. These three factors all favor faster adjustment of bedforms to rising flows. We experimentally demonstrate this bedform adjustment hysteresis through a variety of increasing and decreasing discharge changes, across both <span class="hlt">sand</span> ripple and dune regimes. Finally, we propose and validate a simple conceptual model for estimating the adjustment timescale based on sediment flux and equilibrium bedform geometry.</p> <div class="credits"> <p class="dwt_author">Martin, R. L.; Jerolmack, D. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014Geomo.222..143V"> <span id="translatedtitle">Sediment transport and mixing depth on a coral reef <span class="hlt">sand</span> apron</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper investigates the mechanics of sediment transport on a subtidal <span class="hlt">sand</span> apron located on a coral reef environment. In this environment 100% of the sediment is carbonate bioclasts generated in situ. The <span class="hlt">sand</span> apron is located on the back reef and only affected by waves during high tides. It is commonly accepted in the literature that <span class="hlt">sand</span> aprons are features that prograde lagoonwards and that most of the progradation occurs during high-energy events. Measurements of water depths, waves, currents and near <span class="hlt">bed</span> suspended sediment concentrations (all at 10 Hz) on the <span class="hlt">sand</span> apron were undertaken over a nine day intensive field campaign over both spring and neap tides; waves and tides were also measured in the lagoon. The topography and bathymetry of the <span class="hlt">sand</span> apron were measured and mixing depth was obtained on three transects using depth of disturbance rods. We found that sediment transport on <span class="hlt">sand</span> aprons is not solely restricted to high-energy events but occurs on a daily basis during spring tides. The main factor controlling the sediment transport was the water depth above the <span class="hlt">bed</span>, with depths of 2-2.3 m allowing waves to promote the most sediment transport. This corresponds to a depth over the reef crest of 1.6-1.9 m. The second most important control was waves; transport was observed when Hs on the apron was 0.1 m or greater. In contrast, current magnitude was not a controlling mechanism for sediment entrainment but did affect sediment transport. The morphology of the <span class="hlt">sand</span> apron was shown to affect the direction of currents with the currents also expected to influence the morphology of the <span class="hlt">sand</span> apron. The currents measured during this field campaign were aligned with a shallow channel in the <span class="hlt">sand</span> apron. Mixing depths were small (< 2.5 cm) yet they were larger than the values predicted by empirical formulae for gentle siliciclastic ocean beaches.</p> <div class="credits"> <p class="dwt_author">Vila-Concejo, Ana; Harris, Daniel L.; Power, Hannah E.; Shannon, Amelia M.; Webster, Jody M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6036741"> <span id="translatedtitle">Movement of tagged dredged <span class="hlt">sand</span> at thalweg disposal sites in the upper Mississippi River</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Thalweg disposal experiments have been conducted at three sites on the upper Mississippi River. During normal channel maintenance, hydraulically dredged <span class="hlt">sand</span> was tagged with <span class="hlt">sand</span> coated with fluorescent dye prior to disposal as a pile in the thalweg. In postdisposal surveys surficial bottom sediment samples were collected in the disposal area and in the thalweg and border areas downstream to determine the movement of the dredged <span class="hlt">sand</span> relative to environmentally sensitive river habitats. The experiments were initiated in successive years, and the tagged <span class="hlt">sand</span> has been tracked for 1 to 3 years, depending on the site. Although the downstream movement of the dredged <span class="hlt">sand</span> was not the same at each site, the general pattern of behavior was similar. Downstream movement was confined primarily to the main channel and occurred in response to periods of high river discharge. There was no statistically significant evidence of dredged <span class="hlt">sand</span> dispersing out of the main channel into nearby border areas or sloughs. The distributions of dyed <span class="hlt">sand</span> in cores from one site suggest that the dredged <span class="hlt">sand</span> has been incorporated into natural <span class="hlt">bed</span> forms. 7 refs., 5 figs.</p> <div class="credits"> <p class="dwt_author">Ditmars, J.D.; McCown, D.L.; Paddock, R.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70022534"> <span id="translatedtitle"><span class="hlt">Bed</span> material transport in the Virgin River, Utah</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Detailed information concerning the rate and particle size distribution of <span class="hlt">bed</span> material transport by streamflows can be very difficult and expensive to obtain, especially where peak streamflows are brief and <span class="hlt">bed</span> material is poorly sorted, including some very large boulders. Such streams, however, are common in steep, arid watersheds. Any computational approach must consider that (1) only the smaller particle sizes present on the streambed move even during large floods and (2) the largest <span class="hlt">bed</span> particles exert a significant form drag on the flow. Conventional methods that rely on a single particle size to estimate the skin friction shear stress acting on the mobile fraction of the <span class="hlt">bed</span> material perform poorly. Instead, for this study, the skin friction shear stress was calculated for the observed range of streamflows by calculating the form drag exerted on the reach-averaged flow field by all particle sizes. Suspended and <span class="hlt">bed</span> load transported rates computed from reach-averaged skin friction shear stress are in excellent agreement with measured transport rates. The computed mean annual <span class="hlt">bed</span> material load, including both <span class="hlt">bed</span> load and suspended load, of the East Fork Virgin River for the water years 1992-1996 was approximately 1.3 x 105 t. A large portion of the <span class="hlt">bed</span> material load consists of <span class="hlt">sand</span>-sized particles, 0.062-1.0 mm in diameter, that are transported in suspension. Such particles, however, constituted only 10% of the surface <span class="hlt">bed</span> material and less than 25% of the subsurface <span class="hlt">bed</span> material. The mean annual quantity of <span class="hlt">bed</span> load transported was 1060 t/yr with a median size of 15 mm.</p> <div class="credits"> <p class="dwt_author">Andrews, E.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JHTS...37...87M"> <span id="translatedtitle">Operation Characteristics in a Fluidized <span class="hlt">Bed</span> Gasifier with Triple-<span class="hlt">beds</span> and Dual Circulation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A new type of circulating fluidized <span class="hlt">bed</span> gasifier was proposed. The main features of this proposed gasifier are the adoption of a triple-<span class="hlt">beds</span> structure (comprising pyrolyzer, gasifier, and combustor), the separation of a circulation path for tar-absorbing material and that for the fuel and silica <span class="hlt">sand</span>. Independent circulation systems are employed for the fuel system and for the tar-absorbing particles, and the pyrolyzer and gasifier each have a two-stage fluidized <span class="hlt">bed</span>: the lower stage is for the fuel system and the upper stage is for the tar-absorbing system. The two circulation systems each have an independent combustor. This new gasifier is called “a fluidized <span class="hlt">bed</span> gasifier with triple-<span class="hlt">beds</span> and dual circulation”. The objectives of this work are to clarify the operation characteristics by using a laboratory-scale cold model. As a result, the stable circulation of the particle in upper and lower stages was able to be verified. Additionally, a wide range of the particle circulation rate, which contains the target value, was obtained. The particle circulation rate can be arranged by pressure drop of riser.</p> <div class="credits"> <p class="dwt_author">Murakami, Takahiro; Asai, Minoru; Suzuki, Yoshizo</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3508180"> <span id="translatedtitle">Sex-Associated Effects on Hematologic and Serum Chemistry Analytes in <span class="hlt">Sand</span> Rats (Psammomys obesus)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">We sought to determine whether sex had a significant effect on the hematologic and serum chemistry analytes in adult <span class="hlt">sand</span> rats (Psammomys obesus) maintained under normal laboratory conditions. According to the few data available for this species, we hypothesized that levels of hematologic and serum chemistry analytes would not differ significantly between clinically normal male and female <span class="hlt">sand</span> rats. Data analysis revealed several significant differences in hematologic parameters between male and female <span class="hlt">sand</span> rats but none for serum biochemistry analytes. The following hematologic parameters were greater in male than in female <span class="hlt">sand</span> rats: RBC count, hemoglobin, hematocrit, <span class="hlt">red</span> cell hemoglobin content, and percentage monocytes. <span class="hlt">Red</span> cell distribution width, hemoglobin distribution width, mean platelet volume, and percentage lymphocytes were greater in female than in male <span class="hlt">sand</span> rats. The sex of adult <span class="hlt">sand</span> rats is a source of variation that must be considered in terms of clinical and research data. The data presented here likely will prove useful in the veterinary medical management of <span class="hlt">sand</span> rat colonies and provide baseline hematologic and serum chemistry analyte information for researchers wishing to use this species. PMID:23294882</p> <div class="credits"> <p class="dwt_author">Kane, Julie D; Steinbach, Thomas J; Sturdivant, Rodney X; Burks, Robert E</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6520485"> <span id="translatedtitle">Sedimentology and stratigraphy of tidal <span class="hlt">sand</span> ridges southwest Florida inner shelf</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Detailed investigation of linear shelf <span class="hlt">sand</span> ridges located off the southwest coast of Florida shows them to be tide-dominated <span class="hlt">sand</span> bodies. These ridges are remarkably similar to the large <span class="hlt">sand</span> ridges of the North Sea, and they have abundant apparent analogs in the stratigraphic record, many of which are important petroleum producers. The Florida ridges are asymmetric in profile, about 10 km long, 1 km wide, with relief of 3-4 m with the adjacent sea <span class="hlt">bed</span>. Extensive tidal current monitoring, sediment distribution patterns and side scan sonar surveys permit characterizing their morphodynamics. Tidal currents show distinct bidirectional patterns with speeds up to 70 cm/s. There is slight flood-dominance, and currents show much higher velocities in the troughs as compared to the crests of the ridges. Megaripples and <span class="hlt">sand</span> waves are widespread and migrate obliquely across the ridges at opposite directions on the gentle and steep side of the ridge. Shallow, high-resolution seismic data and 39 vibracores din the area of the ridges show a consistent sequence characterized by three ascending Holocene lithofacies: (1) muddy quartz <span class="hlt">sand</span> with limestone clasts; (2) bioturbated muddy shelly quartz <span class="hlt">sand</span>; and (3) well-sorted, cross-stratified quartz <span class="hlt">sand</span> that characterizes the <span class="hlt">sand</span> ridges themselves. Each of the tidal <span class="hlt">sand</span> ridges displays a coarsening-upward sequence of fine, well-sorted <span class="hlt">sand</span>. Small-scale, multidirectional, cross stratification dominates the stratigraphy of the cores in this facies, but megaripple cross stratification is also present. All data indicate that these tidal ridges are good modern analogs for many of the shelf <span class="hlt">sand</span> bodies in the ancient record, especially the Mesozoic of the mid-continent area.</p> <div class="credits"> <p class="dwt_author">Davis, R.A. Jr.; Klay, J.; Jewell, P. (Univ. of South Florida, Tampa (United States))</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFMED11A1190K"> <span id="translatedtitle"><span class="hlt">Sand</span>, Syrup and Supervolcanoes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Supervolcanic eruptions are amongst the most awesome events in the history of the Earth. A supervolcano can erupt thousands of cubic kilometers of ash devastating entire countries and changing the climate for decades. During the eruption, the magma chamber partially empties and collapses. As the chamber collapses at depth, a massive subsidence pit develops at the surface, called a caldera, some calderas can be the size of the entire San Francisco Bay Area. Fortunately, a supervolcano of this size has not erupted since the development of modern man. Due to the infrequency and massive scale of these eruptions, volcanologists do not yet fully understand how calderas form and how the eruption is affected by the roof collapse and vice versa. Therefore, simple analogue experiments are amongst the best ways to understand these eruptions. We present two of these experiments that can be fun, cheap, and helpful to high school and university instructors to demonstrate caldera formation. The first experiment illustrates how magma chamber roofs collapse to produce different style calderas, the second experiment demonstrates how the magma in the chamber affects the collapse style and magma mixing during a supervolcanic eruption. The collapse of a magma chamber can be demonstrated in a simple sandbox containing a buried balloon filled with air connected to a tube that leads out of the sandbox. At this small scale the buried balloon is a good analogue for a magma chamber and <span class="hlt">sand</span> has an appropriate strength to represent the earths crust. Faults propagate through the <span class="hlt">sand</span> in a similar way to faults propagating through the crust on a larger scale. To form a caldera just let the air erupt out of the balloon. This experiment can be used to investigate what controls the shape and structure of calderas. Different shaped balloons, and different burial depths all produce <span class="hlt">sand</span> calderas with different sizes and structures. Additionally, experiments can be done that erupt only part of the volume of the balloon. These sandbox experiments can be compared to natural calderas and help us understand their internal structure. The second experiment helps us understand how magma behaves during collapse. For this experiment we allowed dense cylindrical blocks to sink into syrup solutions filled with poppy seeds. We mix the syrup with warm water to reduce its viscosity. A series of sinking experiments can be done at different viscosities to investigate different regimes of fluid flow. A key parameter used to the character of the flow of magma is the Reynolds number, the ratio between inertial and viscous forces. The experiments show how the Reynolds number of the magma affects the speed and the style that the block sinks, and also how the magma behaves in the chamber. Fast subsidence in low viscosity fluid (high Reynolds numbers) produces seed vortices in the syrup, indicating mixing. This experiment helps us understand the interplay between eruption and collapse and why mixed magma frequently erupts from calderas. These two simple experiments not only demonstrate caldera formation, but also can be used to get quantative information about the processes governing caldera formation.</p> <div class="credits"> <p class="dwt_author">Kennedy, B.; Jellinek, M.; Stix, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70035019"> <span id="translatedtitle">Predicting fractional <span class="hlt">bed</span> load transport rates: Application of the Wilcock-Crowe equations to a regulated gravel <span class="hlt">bed</span> river</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary"><span class="hlt">Bed</span> load samples from four locations in the Trinity River of northern California are analyzed to evaluate the performance of the Wilcock-Crowe <span class="hlt">bed</span> load transport equations for predicting fractional <span class="hlt">bed</span> load transport rates. <span class="hlt">Bed</span> surface particles become smaller and the fraction of <span class="hlt">sand</span> on the <span class="hlt">bed</span> increases with distance downstream from Lewiston Dam. The dimensionless reference shear stress for the mean <span class="hlt">bed</span> particle size (t*rm) is largest near the dam, but varies relatively little between the more downstream locations. The relation between t*rm and the reference shear stresses for other size fractions is constant across all locations. Total <span class="hlt">bed</span> load transport rates predicted with the Wilcock-Crowe equations are within a factor of 2 of sampled transport rates for 68% of all samples. The Wilcock-Crowe equations nonetheless consistently under-predict the transport of particles larger than 128 mm, frequently by more than an order of magnitude. Accurate prediction of the transport rates of the largest particles is important for models in which the evolution of the surface grain size distribution determines subsequent <span class="hlt">bed</span> load transport rates. Values of term estimated from <span class="hlt">bed</span> load samples are up to 50% larger than those predicted with the Wilcock-Crowe equations, and sampled <span class="hlt">bed</span> load transport approximates equal mobility across a wider range of grain sizes than is implied by the equations. Modifications to theWilcock-Crowe equation for determining t*rm and the hiding function used to scale term to other grain size fractions are proposed to achieve the best fit to observed <span class="hlt">bed</span> load transport in the Trinity River. Copyright 2009 by the American eophysical Union.</p> <div class="credits"> <p class="dwt_author">Gaeuman, D.; Andrews, E.D.; Kraus, A.; Smith, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21425272"> <span id="translatedtitle"><span class="hlt">Bed</span> rest in pregnancy.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The use of <span class="hlt">bed</span> rest in medicine dates back to Hippocrates, who first recommended <span class="hlt">bed</span> rest as a restorative measure for pain. With the formalization of prenatal care in the early 1900s, maternal <span class="hlt">bed</span> rest became a standard of care, especially toward the end of pregnancy. Antepartum <span class="hlt">bed</span> rest is a common obstetric management tool, with up to 95% of obstetricians utilizing maternal activity restriction in some way in their practice. <span class="hlt">Bed</span> rest is prescribed for a variety of complications of pregnancy, from threatened abortion and multiple gestations to preeclampsia and preterm labor. Although the use of <span class="hlt">bed</span> rest is pervasive, there is a paucity of data to support its use. Additionally, many well-documented adverse physical, psychological, familial, societal, and financial effects have been discussed in the literature. There have been no complications of pregnancy for which the literature consistently demonstrates a benefit to antepartum <span class="hlt">bed</span> rest. Given the well-documented adverse effects of <span class="hlt">bed</span> rest, disruption of social relationships, and financial implications of this intervention, there is a real need for scientific investigation to establish whether this is an appropriate therapeutic modality. Well-designed randomized, controlled trials of <span class="hlt">bed</span> rest versus normal activity for various complications of pregnancy are required to lay this debate to rest once and for all. PMID:21425272</p> <div class="credits"> <p class="dwt_author">Bigelow, Catherine; Stone, Joanne</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6049822"> <span id="translatedtitle"><span class="hlt">Sand</span> control system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A method is described for controlling <span class="hlt">sands</span> in a wellbore, the method comprising the steps of: introducing an amount of particles into the wellbore, introducing a tubular string into the particles and moving the string downwardly in the particles, the tubular string having swivel means for rotatably connecting an entry tool to the string, the swivel means connected between the string and the entry tool, the swivel means having a diameter no greater than the diameter of the string, the entry tool mounted to the swivel means for relative rotation. The tool has auger means for facilitating the introduction of the string into the particles. A tool for facilitating the introduction of a tubular string into an accumulation of particles in a wellbore has perforations for production. The tool comprises: body means; rotative connection means for rotatably connecting the body means to the string for relative rotation; the rotative connection means connects between the string and the body means and has a diameter no greater than the diameter of the string; and auger means connects to the body means for augering into the particles and for facilitating the movement of particles into the perforations.</p> <div class="credits"> <p class="dwt_author">Guidry, J.P.; Gavranovic, L.R.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-07-21</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4149430"> <span id="translatedtitle">Saltation of Non-Spherical <span class="hlt">Sand</span> Particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, <span class="hlt">sand</span> particles in most of the existing wind <span class="hlt">sand</span> movement models are considered to be spherical, the effects of the <span class="hlt">sand</span> shape on the structure of the wind <span class="hlt">sand</span> flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, <span class="hlt">sand</span> grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of <span class="hlt">sand</span> grains with different shapes in the saltation process, then established a <span class="hlt">sand</span> saltation model that considers the coupling effect between wind and the <span class="hlt">sand</span> grains, the effect of the mid-air collision of <span class="hlt">sand</span> grains, and the effect of the <span class="hlt">sand</span> grain shape. Based on this model, the saltation process and <span class="hlt">sand</span> transport rate of non-spherical <span class="hlt">sand</span> particles were simulated. The results show that the <span class="hlt">sand</span> shape has a significant impact on the saltation process; for the same wind speed, the <span class="hlt">sand</span> transport rates varied for different shapes of <span class="hlt">sand</span> grains by as much as several-fold. Therefore, <span class="hlt">sand</span> shape is one of the important factors affecting wind-<span class="hlt">sand</span> movement. PMID:25170614</p> <div class="credits"> <p class="dwt_author">Wang, Zhengshi; Ren, Shan; Huang, Ning</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860031091&hterms=bone+marrow+erythropoiesis&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbone%2Bmarrow%2Berythropoiesis"> <span id="translatedtitle"><span class="hlt">Red</span> blood cell decreases of microgravity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Postflight decreases in <span class="hlt">red</span> blood cell mass (RBCM) have regularly been recorded after exposure to microgravity. These 5-25 percent decreases do not relate to the mission duration, workload, caloric intake or to the type of spacecraft used. The decrease is accompanied by normal <span class="hlt">red</span> cell survivals, increased ferritin levels, normal radioactive iron studies, and increases in mean <span class="hlt">red</span> blood cell volume. Comparable decreases in <span class="hlt">red</span> blood cell mass are not found after <span class="hlt">bed</span> rest, a commonly used simulation of the microgravity state. Inhibited bone marrow erythropoiesis has not been proven to date, although reticulocyte numbers in the peripheral circulation are decreased about 50 percent. To date, the cause of the microgravity induced decreases in RBCM is unknown. Increased splenic trapping of circulating <span class="hlt">red</span> blood cells seem the most logical way to explain the results obtained.</p> <div class="credits"> <p class="dwt_author">Johnson, P. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/ETD-TAMU-1998-THESIS-D455"> <span id="translatedtitle">Laboratory compaction of cohesionless <span class="hlt">sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">A total of 62 cohesiveness <span class="hlt">sands</span> were tested to rographics. investigate the importance of the water content, grain size distribution, grading of the soil, particle shape, grain crushing during testing and laboratory compaction test method...</p> <div class="credits"> <p class="dwt_author">Delphia, John Girard</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-07</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a style="font-weight: bold;">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_15");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997ConPh..38..329S"> <span id="translatedtitle">Sound-producing <span class="hlt">sand</span> avalanches</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sound-producing <span class="hlt">sand</span> grains constitute one of nature's more puzzling and least understood physical phenomena. They occur naturally in two distinct types: booming and squeaking <span class="hlt">sands</span>. Although both varieties of <span class="hlt">sand</span> produce unexpectedly pure acoustic emissions when sheared, they differ in their frequency range and duration of emission, as well as the environment in which they tend to be found. Large-scale slumping events on dry booming dunes can produce acoustic emissions that can be heard up to 10 km away and which resemble hums, moans, drums, thunder, foghorns or the drone of low-flying propeller aircraft. These analogies emphasize the uniqueness of the phenomenon and the clarity of the produced sound. Although reports of these <span class="hlt">sands</span> have existed in the literature for over one thousand years, a satisfactory explanation for either type of acoustic emission is still unavailable.</p> <div class="credits"> <p class="dwt_author">Sholtz, Paul; Bretz, Michael; Nori, Franco</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005EL.....69..365B"> <span id="translatedtitle">Non-aeolian <span class="hlt">sand</span> ripples</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">By examining the initial stages of the impact of a granular jet on a flat horizontal solid surface we evidenced the existence of oscillatory <span class="hlt">sand</span> fronts. These oscillations give rise to a novel mechanism for the formation of ripples on <span class="hlt">sand</span> surfaces. We here show that as the front advances, its slope changes periodically in time, leaving behind a succession of surface elevations and depressions. A key feature of these oscillations is the interplay between the deposition of mobile <span class="hlt">sand</span> and the avalanching of the static parts giving rise to a remarkable self-regulating system. These features come out naturally from a simplified version of recently proposed models for the dynamics of <span class="hlt">sand</span> piles.</p> <div class="credits"> <p class="dwt_author">Boudet, J. F.; Amarouchene, Y.; Bonnier, B.; Kellay, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/ETD-TAMU-1961-THESIS-H887"> <span id="translatedtitle">Sesame fertilization on lakeland <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">SESAME FERTILIZATION ON LAKELAND <span class="hlt">SAND</span> A Thesis RAMON HUERTA M. Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1961... Ma/or Sub]ect: Agronomy SESAME FERTILIZATION ON LAKELAND <span class="hlt">SAND</span> A Thesis RAMON HUERTA M. Approved as to style and content hy: Chairssn of Conunittee Head of partment January 1961 ACKNOWLEDGEMENTS The author wishes to express his sincere...</p> <div class="credits"> <p class="dwt_author">Huerta, Ramon Moreno</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-07</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://kidshealth.org/parent/pregnancy_center/your_pregnancy/bed_rest.html"> <span id="translatedtitle">Surviving <span class="hlt">Bed</span> Rest</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://medlineplus.gov/">MedlinePLUS</a></p> <p class="result-summary">... Rest Help? Women with pregnancy conditions related to high blood pressure may be placed on <span class="hlt">bed</span> rest to decrease stress, both physical and emotional, with the hope of lowering their blood pressure. Vaginal bleeding can be aggravated by activity, lifting, or exercise, so <span class="hlt">bed</span> rest also might be ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/866638"> <span id="translatedtitle">Fluidized <span class="hlt">bed</span> calciner apparatus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">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 <span class="hlt">bed</span> 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 <span class="hlt">bed</span> is a support member for supporting the fluidized <span class="hlt">bed</span>, the support member having uniform slots for directing uniform gas flow to the fluidized <span class="hlt">bed</span> 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 <span class="hlt">bed</span>. 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 <span class="hlt">bed</span>. Further, connected to the internal and external heaters is a means for maintaining the fluidized <span class="hlt">bed</span> temperature to within plus or minus approximately 25.degree. C. of a predetermined <span class="hlt">bed</span> temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.</p> <div class="credits"> <p class="dwt_author">Owen, Thomas J. (West Richland, WA); Klem, Jr., Michael J. (Richland, WA); Cash, Robert J. (Richland, WA)</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/634716"> <span id="translatedtitle">Agglomeration characteristics of silica <span class="hlt">sand</span>-rice husk ash mixtures at elevated temperatures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Rice husk, a major by-product of the rice milling process, can be a significant energy resource in rice producing countries because of its high energy content. Fluidized <span class="hlt">bed</span> gasifiers have been proposed for the recovery of energy from rice husk. The major advantage of fluidized <span class="hlt">bed</span> gasifiers over fixed <span class="hlt">bed</span> gasifiers is the high mass and heat transfer capability due to very high percentage of inert <span class="hlt">bed</span> material such as silica <span class="hlt">sand</span>. In addition, the vigorous mixing and agitation of solid particles in fluidized <span class="hlt">beds</span> promote a uniform temperature distribution and a high conversion efficiency. However, attempts to utilize rice husk as a feed in fluidized <span class="hlt">bed</span> gasifiers have been unsuccessful because of the high ash content of rice husk that may result in the agglomeration of inert <span class="hlt">bed</span> materials at high temperatures. In this work, the effect of rice husk ash content on the agglomeration characteristics of silica <span class="hlt">sand</span> was investigated at various temperatures using a muffle furnace. A light microscope, an environmental scanning electron microscope, and an energy dispersive X-ray analyzer were used to characterize the structural changes and elemental makeup of the samples. There was no indication of agglomeration below 850 C, but at temperatures of 850--1,000 C the silica <span class="hlt">sand</span> loosely agglomerated in the presence of rice husk ash at all levels of ash content. The effect was more pronounced at 1,000 C. The chemical interaction of the SiO{sub 2} and the low melting temperature mineral oxides present in notably low concentrations in rice husk ash, appeared to be the mechanism resulting in the formation of the loose agglomerates.</p> <div class="credits"> <p class="dwt_author">Mansaray, K.G.; Ghaly, A.E. [Technical Univ. of Nova Scotia, Halifax (Canada). Agricultural Engineering Dept.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17363038"> <span id="translatedtitle">Arsenic removal from water using natural iron mineral-quartz <span class="hlt">sand</span> columns.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The study has investigated the feasibility of using siderite-coated quartz <span class="hlt">sand</span> and/or hematite-coated quartz <span class="hlt">sand</span> columns for removing As from water. Arsenic-spiked tap water and synthetic As solution with As concentrations from 200 to 500 mug/L were used for the experiments. Since three coating methods employed to prepare siderite-coated quartz <span class="hlt">sand</span> and hematite-coated quartz <span class="hlt">sand</span> had no significant impact on As adsorption in batch tests, the column fillings were produced by means of the simplest one involving mechanically mixing the Fe mineral with quartz <span class="hlt">sand</span>. Fixed <span class="hlt">bed</span> tests show that the combination of siderite-coated quartz <span class="hlt">sand</span> and hematite-coated quartz <span class="hlt">sand</span> greatly promoted the column performance in removing As and the presence of As(III) in the influent improved the removal efficiency of the column. The relatively low capacity in treating As-spiked tap water arose from the suppression of FeCO(3) dissolution in the presence of high HCO(3)(-) concentration (333 mg/L), which consequently limited the formation of fresh Fe(III) oxides. However, the H(2)O(2)-conditioning greatly increased As adsorption capacity of the column for remediating As-spiked tap water. The Toxicity Characteristic Leaching Procedure (TCLP) test shows that the spent adsorbents were not hazardous and could be safely disposed of to landfill. PMID:17363038</p> <div class="credits"> <p class="dwt_author">Guo, Huaming; Stüben, Doris; Berner, Zolt</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-05-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/588916"> <span id="translatedtitle">Acidic stream mitigation by limestone <span class="hlt">sand</span> addition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Town Line Run watershed comprises an area of 3,600 wooded acres. The tributaries feeding the stream consist of sandstone springs that do not contribute alkalinity to the watershed, leaving the stream susceptible to acid precipitation. This has a negative affect on Iser`s Run, a native brook trout fishery above the confluence with Town Line Run. The objective in stream liming is to improve water chemistry by increasing pH, alkalinity, and reducing acidity, aluminum, and iron. Introducing crushed limestone directly into a stream from a dump truck is an inexpensive but temporary solution to accomplish this objective. In this type of liming operation, a <span class="hlt">bed</span> of limestone is spread down the stream channel by the momentum of the stream from the introduction point, rather than manually. Water moving across this <span class="hlt">bed</span> dissolves the limestone, increasing the pH, alkalinity, and calcium while decreasing the acidity, iron, and aluminum concentrations of the water. The size of the limestone particles is important for this purpose because particles that are too small (<150 microns) will carried away, while particles that are too large (>1000 microns) will remain at the introduction point. Our study placed 80 tons of <span class="hlt">sand</span>-sized limestone (85% calcite) in the stream channel at a single point. Water samples were collected monthly at the following sites (1) directly upstream of the addition site, (2) 100 yards downstream of the site, and (3) 2500 yards downstream of the site. Other sample locations include (4) upstream and (5) downstream of the Town Line Run- Iser`s Run confluence and the Casselman River upstream (6) and downstream (7) of Town Line Run. The samples were analyzed for pH. Specific conductivity, Alkalinity, Acidity, Iron, Manganese, Aluminum, and Sulfate.</p> <div class="credits"> <p class="dwt_author">Brant, D.L. [WVU National Research Center for Coal and Energy, Morgantown, WV (United States); Marich, A.J. Jr. [PA Dept. of Environmental Protection, Markleton, PA (United States); Largent, K.L. [Somerset Conservation District, Somerset, PA (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-12-31</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMEP51A0696P"> <span id="translatedtitle">Modeling <span class="hlt">bed</span> material transport through colonial-age mill dam impoundments, northern Delaware</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Two hundred -year old colonial mill dam impoundments of the White Clay and <span class="hlt">Red</span> Clay Creeks in northern Delaware are barely 20% 'filled' with sediment. Field evidence suggests that gravel-sized <span class="hlt">bed</span> material supplied from upstream is able to pass through these impoundments, implying that the impoundment morphology has reached an equilibrium morphology controlled by the prevailing hydraulic regime. We assess this hypothesis using backwater modeling to compute local boundary shear stresses and the Wilcock-Crowe sediment transport equation to determine <span class="hlt">bed</span> material transport rates in a representative impoundment with a ~ 2 m high dam and a 1.5 km-long impoundment. While previous conceptual models suggest that cobbles could only be transported through impoundments during catastrophic storm events or after impoundments had completely filled, our analysis demonstrates that transport rates of cobbles during the 2 year flow are significant. Even smaller discharges can be effective: the 0.5 year discharge moves coarse-grained <span class="hlt">bed</span> material (11.2 - 32 mm) at moderate rates outside the impoundment and at low rates within the impoundment, suggesting net accumulation. Larger flows (5-25 year) transport material at similar rates both outside and within the impoundment. Averaged over time, this regime would keep the <span class="hlt">bed</span> of the stream in quasi-equilibrium, with lower flows filling the impoundment and higher flows removing the accumulated sediment. This behavior is reminiscent of the response and recovery cycle described for quasi-equilibrium stream channels, suggesting that these impounded channels behave as graded streams with a reduced slope rather than as stagnant quasi-lacustrine systems incapable of transporting the sediment supplied from upstream. The current morphology (only 20% filled by <span class="hlt">sand</span> and gravel) may not have existed in the past. Cores from floodplains adjacent to the impoundments reveal deposits of laminated mud suggesting a former fine-grained impoundment fill that has subsequently been eroded. Changes in land use and spillway operation have likely altered the discharge regime, sediment supply, and hydraulics of the impoundment, creating a different impoundment morphology. Our study suggests that the morphology of impoundment streams adjusts through time to achieve a quasi-equilibrium morphology controlled by the prevailing sediment supply and hydraulic regime.</p> <div class="credits"> <p class="dwt_author">Pearson, A.; Pizzuto, J. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005ECSS...63..385E"> <span id="translatedtitle">Differences in macrofaunal and seagrass assemblages in seagrass <span class="hlt">beds</span> with and without seaweed farms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Since it was introduced to Zanzibar (Tanzania), seaweed farming has significantly contributed to local, socio-economic development. However, several investigations have shown impacts on the coastal environment near where the farms are located. As many seaweed farms are located on seagrass <span class="hlt">beds</span>, there is a risk that seaweed farming could affect seagrass <span class="hlt">beds</span>, and thereby disturb important ecosystem functions and the flow of ecological goods and services. This study compares characteristics of macrophytes (focusing on seagrasses), benthic macrofauna and sediment in seagrass <span class="hlt">beds</span>, with and without seaweed farms, and a <span class="hlt">sand</span> bank without vegetation in Chwaka Bay, Zanzibar. The results showed that seagrass <span class="hlt">beds</span> underneath seaweed farms generally had less seagrass and macroalgae, finer sediment, lower sediment organic matter content and a reduced abundance and biomass of macrofauna, than seagrass <span class="hlt">beds</span> without seaweed farms. Further, the macrofaunal community structure in seaweed farms showed more similarities to that on the <span class="hlt">sand</span> bank than in the unfarmed seagrass <span class="hlt">beds</span>. Most of the dissimilarity was attributable to Lucinidae (suspension-feeding bivalves), which were almost absent in the seaweed farms, resulting in the large difference in biomass between the seaweed farms and the unfarmed seagrass <span class="hlt">beds</span>. When interpreted together with information from farmers, the observed pattern is believed to be caused by the seaweed farming activities. This indicates that more research is needed to establish the effects of seaweed farming on seagrass <span class="hlt">beds</span>, and that more attention should be given to the location of farms and the choice of farming methods.</p> <div class="credits"> <p class="dwt_author">Eklöf, J. S.; de la Torre Castro, M.; Adelsköld, L.; Jiddawi, N. S.; Kautsky, N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/wri854195"> <span id="translatedtitle">Evaluation of surface geophysical methods for collection of hydrogeologic data in the Nebraska <span class="hlt">Sand</span> Hills region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The practicality of using surface geophysical methods for obtaining geohydrologic data in the Nebraska <span class="hlt">Sand</span> Hills region was studied during the summer of 1984. Seismic refraction and electrical-resistivity equipment were used, because an evaluation of geohydrologic data indicated that results of surveys made with this equipment probably would yield the most useful data. The study area, which included parts of Garfield, Holt, and Wheeler Counties, was selected because it is geohydrologically representative of the eastern part of the <span class="hlt">Sand</span> Hills region, and because sufficient geohydrologic data were available for use in evaluating the results of geophysical surveys. Geophysical methods were evaluated for their ability to consistently detect selected geohydrologic horizons. These horizons in descending order, are: the water table, the top of Quaternary silt <span class="hlt">beds</span>, the top of Quaternary <span class="hlt">sand</span> and gravel <span class="hlt">beds</span> , the top of the Tertiary Ogallala Formation, and the top of the Cretaceous Pierre Shale. The top of the Pierre Shale generally is the base of the aquifer, which consists of all of the 500 to 700 ft of overlying deposits. Evaluations of the geophysical data indicate that seismic refraction surveys are best suited for determining the depth to the water table, but are not effective in studying <span class="hlt">beds</span> below the water table. Vertical electrical soundings provided data on the depth to water table and the top of the silt <span class="hlt">beds</span>. Available geohydrologic data, however, indicate that with some changes in data collection or interpretation techniques, it may be possible to obtain information on the top of the <span class="hlt">sand</span> and gravel deposits, the top of the Ogallala Formation, and the top of the Pierre Shale with vertical electrical soundings. Use of either geophysical method could enhance the results of geohydrologic investigations in the Nebraska <span class="hlt">Sand</span> Hills region. (Author 's abstract)</p> <div class="credits"> <p class="dwt_author">Ellis, M.J.; Hiergesell, R.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70031219"> <span id="translatedtitle">Measuring <span class="hlt">bed</span> load discharge in rivers: bedload-surrogate monitoring workshop Minneapolis, Minnesota, 11-14 April 2007</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The International Bedload-Surrogate Monitoring Workshop (http://www.nced.umn.edu/BRIC_2007.html), organized by the Bedload Research International Cooperative (BRIC; www.bedloadresearch.org), was held to assess and abet progress in continuous, semiautomated, or fully automated (surrogate) technologies for monitoring <span class="hlt">bed</span> load discharge in gravel-, <span class="hlt">sand</span>-, and mixed gravel-<span class="hlt">sand-bedded</span> rivers. Direct <span class="hlt">bed</span> load measurements, particularly at medium and high flows, during which most <span class="hlt">bed</span> load occurs, tend to be time-consuming, expensive, and potentially hazardous. Surrogate technologies developed largely over the past decade and used at a number of research sites around the world show considerable promise toward providing relatively dense, robust, and quantifiably reliable <span class="hlt">bed</span> load data sets. However, information on the efficacy of selected technologies for use in monitoring programs is needed, as is identification of the ways and means for bringing the most promising and practical of the technologies to fruition.</p> <div class="credits"> <p class="dwt_author">Gray, John R.; Laronne, Jonathan B.; Marr, Jeffrey D.G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70015064"> <span id="translatedtitle">Controls on the composition of fluvial <span class="hlt">sands</span> from a tropical weathering environment: <span class="hlt">sands</span> of the Orinoco River drainage basin, Venezuela and Colombia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">On the alluvial plains of the western Llanos, storage of orogenically derived sediment allows time for substantial chemical weathering. Through reworking of the alluvial sequences, freshly eroded sediment is exchanged for older, compositionally more mature material. The chemically weathered component increases as rivers cross the Llanos, resulting in an increase in overall compositional maturity of <span class="hlt">bed</span>-load <span class="hlt">sand</span> away from the orogenic terranes. -from Authors</p> <div class="credits"> <p class="dwt_author">Johnsson, M.J.; Stallard, R.F.; Lundberg, N.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5026539"> <span id="translatedtitle">Relationship between bedload and suspended <span class="hlt">sand</span> transport on the inner shelf, Long Island, New York</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Data obtained by a near-bottom Profiling Concentration and Velocity system (PCV), deployed in 10 m water depth at a site 1 km from the Long Island coastline, are used to examine links between bedload and suspended <span class="hlt">sand</span> concentrations. Calculations of bedload areal concentration C* are based on the empirical results of Vincent et al. (1981) and use the theoretical formulations of Grant and Madsen (1978,1979) to describe the interaction between wave and current boundary layers. Suspended <span class="hlt">sand</span> concentrations were obtained directly from an Acoustic Concentration Meter (ACM). Average suspended <span class="hlt">sand</span> profiles C/sub z/ were found to fit closely to a log-linear profile C/sub z/ = C/sub 1/(1--A log/sub e/ Z/Z/sub 1/), where C/sub 1/ is the <span class="hlt">sand</span> concentration at a height Z/sub 1/ = 1 cm from the <span class="hlt">bed</span> and A is empirically determined as 0.22 +- 0.0005. A linear correlation is observed between the areal bedload concentration C* (the volume of bedload per unit area of the <span class="hlt">bed</span>) and the suspended <span class="hlt">sand</span> concentration 1 cm above the <span class="hlt">bed</span> C/sub 1/, with a correlation of 0.82 (significant at the 1% level), and supports the hypothesis of Einstein (1950) that bedload and suspended load are related through bedload concentration. It is also shown that the sedment threshold criterion of Komar and Miller (1973), when expressed as ratio (here called the Komar ratio), can be used as a useful predictor for C/sub 1/ under conditions where the wave orbital currents are much greater than the mean flow. These relationships offer the opportunity for the calculation of both bedload and suspended <span class="hlt">sand</span> transport rates from measurements of the steady current velocity and wave parameters, combined with information defining the surficial sediments and local bottom topography.</p> <div class="credits"> <p class="dwt_author">Vincent, C.E.; Young, R.A.; Swift, D.J.P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-05-20</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24908577"> <span id="translatedtitle">Replicating the microbial community and water quality performance of full-scale slow <span class="hlt">sand</span> filters in laboratory-scale filters.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Previous laboratory-scale studies to characterise the functional microbial ecology of slow <span class="hlt">sand</span> filters have suffered from methodological limitations that could compromise their relevance to full-scale systems. Therefore, to ascertain if laboratory-scale slow <span class="hlt">sand</span> filters (L-SSFs) can replicate the microbial community and water quality production of industrially operated full-scale slow <span class="hlt">sand</span> filters (I-SSFs), eight cylindrical L-SSFs were constructed and were used to treat water from the same source as the I-SSFs. Half of the L-SSFs <span class="hlt">sand</span> <span class="hlt">beds</span> were composed of sterilized <span class="hlt">sand</span> (sterile) from the industrial filters and the other half with <span class="hlt">sand</span> taken directly from the same industrial filter (non-sterile). All filters were operated for 10 weeks, with the microbial community and water quality parameters sampled and analysed weekly. To characterize the microbial community phyla-specific qPCR assays and 454 pyrosequencing of the 16S rRNA gene were used in conjunction with an array of statistical techniques. The results demonstrate that it is possible to mimic both the water quality production and the structure of the microbial community of full-scale filters in the laboratory - at all levels of taxonomic classification except OTU - thus allowing comparison of LSSF experiments with full-scale units. Further, it was found that the <span class="hlt">sand</span> type composing the filter <span class="hlt">bed</span> (non-sterile or sterile), the water quality produced, the age of the filters and the depth of <span class="hlt">sand</span> samples were all significant factors in explaining observed differences in the structure of the microbial consortia. This study is the first to the authors' knowledge that demonstrates that scaled-down slow <span class="hlt">sand</span> filters can accurately reproduce the water quality and microbial consortia of full-scale slow <span class="hlt">sand</span> filters. PMID:24908577</p> <div class="credits"> <p class="dwt_author">Haig, Sarah-Jane; Quince, Christopher; Davies, Robert L; Dorea, Caetano C; Collins, Gavin</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26498336"> <span id="translatedtitle">Bottom <span class="hlt">bed</span> regimes in a circulating fluidized <span class="hlt">bed</span> boiler</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper extends previous work on the fluidization regimes of the bottom <span class="hlt">bed</span> of circulating flyidized <span class="hlt">bed</span> (CFB) boilers. Pressure measurements were performed to obtain the time-average bottom <span class="hlt">bed</span> voidage and to study the <span class="hlt">bed</span> pressure fluctuations. The measurements were carried out in a 12 MWth CFB boiler operated at 850°C and also under ambient conditions (40°C). Two bubbling regimes</p> <div class="credits"> <p class="dwt_author">A. Svensson; F. Johnsson; B. Leckner</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/0805.0086v1"> <span id="translatedtitle">Erosion of a granular <span class="hlt">bed</span> driven by laminar fluid flow</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Motivated by examples of erosive incision of channels in <span class="hlt">sand</span>, we investigate the motion of individual grains in a granular <span class="hlt">bed</span> driven by a laminar fluid to give us new insights into the relationship between hydrodynamic stress and surface granular flow. A closed cell of rectangular cross-section is partially filled with glass beads and a constant fluid flux $Q$ flows through the cell. The refractive indices of the fluid and the glass beads are matched and the cell is illuminated with a laser sheet, allowing us to image individual beads. The <span class="hlt">bed</span> erodes to a rest height $h_r$ which depends on $Q$. The Shields threshold criterion assumes that the non-dimensional ratio $\\theta$ of the viscous stress on the <span class="hlt">bed</span> to the hydrostatic pressure difference across a grain is sufficient to predict the granular flux. Furthermore, the Shields criterion states that the granular flux is non-zero only for $\\theta >\\theta_c$. We find that the Shields criterion describes the observed relationship $h_r \\propto Q^{1/2}$ when the <span class="hlt">bed</span> height is offset by approximately half a grain diameter. Introducing this offset in the estimation of $\\theta$ yields a collapse of the measured Einstein number $q^*$ to a power-law function of $\\theta - \\theta_c$ with exponent $1.75 \\pm 0.25$. The dynamics of the <span class="hlt">bed</span> height relaxation are well described by the power law relationship between the granular flux and the <span class="hlt">bed</span> stress.</p> <div class="credits"> <p class="dwt_author">A. E. Lobkovsky; A. V. Orpe; R. Molloy; A. Kudrolli; D. H. Rothman</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA453897"> <span id="translatedtitle">Fluidized <span class="hlt">Bed</span> Biodenitrification Process.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> biodenitrification process was operated at bench- scale on simulated high nitrate waste waters. Early results with a cylindrical column were poor but very markedly improved with a change to a conical shaped column. Nitrate reduction effici...</p> <div class="credits"> <p class="dwt_author">T. M. Wendt, J. P. Heider, A. M. Kaplan</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cdc.gov/parasites/bedbugs/faqs.html"> <span id="translatedtitle"><span class="hlt">Bed</span> Bugs FAQs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://medlineplus.gov/">MedlinePLUS</a></p> <p class="result-summary">... <span class="hlt">Bed</span> bugs have been found in five-star hotels and resorts and their presence is not determined ... sleep. These areas include apartments, shelters, rooming houses, hotels, cruise ships, buses, trains, and dorm rooms. They ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N20050207557"> <span id="translatedtitle">Deep Space Test <span class="hlt">Bed</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This viewgraph presentation describes the Deep Space Test <span class="hlt">Bed</span> (DSTB), a balloon-borne device which can expose multiple payloads to the interplanetary Galactic Cosmic Ray environment on high altitude polar balloon flights. The DSTB is carried by National S...</p> <div class="credits"> <p class="dwt_author">M. E. Milton</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a style="font-weight: bold;">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_16");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JGRE..119..941C"> <span id="translatedtitle"><span class="hlt">Sands</span> at Gusev Crater, Mars</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">environments, and the energy associated with the transport and deposition of <span class="hlt">sand</span> at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium <span class="hlt">sand</span> is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine <span class="hlt">sand</span> during active erosion, or alternatively, by excess accumulation of coarse <span class="hlt">sand</span> from a local source. The coarse to very coarse <span class="hlt">sand</span> particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce <span class="hlt">sands</span> with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).</p> <div class="credits"> <p class="dwt_author">Cabrol, Nathalie A.; Herkenhoff, Kenneth; Knoll, Andrew H.; Farmer, Jack; Arvidson, Raymond; Grin, Edmond; Li, Ronxing; Fenton, Lori; Cohen, Barbara; Bell, James F.; Aileen Yingst, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5990891"> <span id="translatedtitle">Sea <span class="hlt">bed</span> mechanics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This book provides a discussion on sea <span class="hlt">bed</span> processes with engineering applications. It brings together the material currently available only in technical reports of research papers. It provides formulae and background references necessary for design calculation of problems such as sea <span class="hlt">bed</span> or coastal erosion, and sub-marine pipeline stability. It also covers dissipation of wave energy, formation of ripples and dunes, and the transportation of sediments.</p> <div class="credits"> <p class="dwt_author">Sleath, J.F.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/tst04_071_07_36"> <span id="translatedtitle">Geology on a <span class="hlt">Sand</span> Budget</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Earth science teaches know how frustrating it can be to spend hundreds of dollars on three-dimensional (3-D) models of Earth's geologic features, only to use the models for a few class periods. To avoid emptying an already limited science budget, teachers can use a simple alternative to the expensive 3-D models--<span class="hlt">sand</span>. Modeling geologic processes and features with <span class="hlt">sand</span> is an effective way for teachers to promote student understanding of Earth science topics, quickly assess students' prior knowledge, and identify common misconceptions.</p> <div class="credits"> <p class="dwt_author">Kane, Jacqueline</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMEP33D..07N"> <span id="translatedtitle"><span class="hlt">Sand</span> transport in the lower Mississippi River does not yield to dams: Applications for building deltaic land in Louisiana</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Mississippi Delta is presently undergoing a catastrophic drowning, whereby 5000 km2 of low-lying wetlands have converted to open water. This land loss is primarily the result of: a) relative sea-level rise, occurring due to the combined effect of rapid subsidence associated with subsurface fluids extraction and eustatic rise; b) leveeing and damming of the river and its tributaries, which restricts sediment delivery to and dispersal within the delta; and c) severe excavation of the delta for navigation channels. It has been argued that continued net land loss of the Mississippi Delta is inevitable due to declining measured total (<span class="hlt">sand</span> and mud) suspended sediment loads over the past 6 decades. However, recent research has documented that the key to delta growth is deposition of <span class="hlt">sand</span>, which accounts for ~50-70% of modern and ancient (up to 9 m.a.) Mississippi Delta deposits, but comprises only ~20% of the sampled portion of the total load. Here we present new analysis of existing data to show that <span class="hlt">sand</span> transport has not diminished since dam construction. Furthermore, we produce a numerical model based on the mass balance of <span class="hlt">bed</span> material loads over the lower 1600 km of the Mississippi River to show that mining of <span class="hlt">sand</span> from the channel <span class="hlt">bed</span> continues to replenish downstream <span class="hlt">sand</span> loads. For example, our model results indicate that it requires approximately 240 years for a reduced <span class="hlt">sand</span> load to reach the delta apex. Furthermore, our calculations indicate that <span class="hlt">sand</span> load at the delta apex is reduced by a noticeable amount (17%) only after about 600 years. We also show how channel <span class="hlt">bed</span> elevations are predicted to change over the lower 1600 km of the river channel due to channel mining. Channel-<span class="hlt">bed</span> degradation is greatest at the upstream end of the study reach and decreases downstream. After 300 years the wave of significant degradation has just passed ~800 km downstream, or roughly half of our model domain. These results are in contrast to the measurements which concern the reduction of total suspended sediment load, and here we provide a reasonable hypothesis to help explain: <span class="hlt">sand</span> possesses a much slower time scale of movement through a <span class="hlt">sand-bed</span> river compared to mud, because <span class="hlt">sand</span> exchanges with the <span class="hlt">bed</span>, building dunes and bars that migrate gradually downstream, whereas the mud travels the length of the system in suspension as washload. This produces orders-of-magnitude difference in transport timescales between mud -- which accounts for ~80% of the total suspended sediment load of the Mississippi River -- and <span class="hlt">sand</span> (bedload and suspended load). Combined with the abundance and availability of <span class="hlt">sand</span> to be mined within the main channel, the river effectively buffers the reduction of <span class="hlt">sand</span> load arising due to main-channel dams. Thus the <span class="hlt">bed</span> of the lower Mississippi River downstream will provide a stable supply of <span class="hlt">sand</span> to the delta for the foreseeable future.</p> <div class="credits"> <p class="dwt_author">Nittrouer, J. A.; Viparelli, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20939414"> <span id="translatedtitle">Experiment and grey relational analysis of CWS spheres combustion in a fluidized <span class="hlt">bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In order to study the combustion of coal water slurry (CWS) in fluidized <span class="hlt">bed</span> boilers, artificial CWS droplet spheres were used for simulation of the spheres formed from CWS droplets which fall from the furnace top to the <span class="hlt">bed</span>. The artificial spheres were introduced to a bench-scale fluidized <span class="hlt">bed</span> furnace. Quartz <span class="hlt">sand</span> was used as the <span class="hlt">bed</span> material. The influence of the operation conditions (e.g., <span class="hlt">bed</span> temperature, superficial gas velocity, and <span class="hlt">bed</span> height) on the combustion characteristics was investigated. The <span class="hlt">bed</span> temperatures were varied at 650, 750, 850, and 950{sup o}C. The gas velocities were in a range of fluidization numbers W (defined as U/U{sub mf}) of 3, 3.5, 4, and 4.5. The <span class="hlt">bed</span> heights were varied 30, 50, 70, and 90 mm. The CWS spheres were taken out at five residence times (15, 30, 45, 60, and 75 s). The mass ratio of the residue fixed carbon to parent fixed carbon was calculated for studying the influential factors. Under the reference conditions, it is shown that the burnout time is less than 150 s. The grey relational analysis was used to study the degree of relative importance of the influential factors. The results showed that the influence of the <span class="hlt">bed</span> height is the least, the fluidization number has the greatest influence in the early and later stages, and the <span class="hlt">bed</span> temperature contributes most in the intermediate stages. 16 refs., 16 figs., 6 tabs.</p> <div class="credits"> <p class="dwt_author">Hui Wang; Xiumin Jiang; Jianguo Liu; Weigang Lin [Shanghai Jiao Tong University, Shanghai (China). School of Mechanical Engineering</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-08-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pbs.org/redfiles/"> <span id="translatedtitle"><span class="hlt">Red</span> Files</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary"><span class="hlt">Red</span> Files, a four-part documentary series from PBS, utilizes previously unavailable archival sources and interviews to present a fascinating look at the Soviet Union and its Cold War rivalry with the US. This attractive companion site offers a number of resources related to each of the four episodes: Secret Victories of the KGB, Soviet Sports Wars, Secret Soviet Moon Mission, and Soviet Propaganda. For each installment, users will find a story synopsis, the Producer's script, theme music, updates on related events, human interest stories, complete interview transcripts, video clips, a reference section, access to related sections of Russian Archives Online, maps, a timeline, lesson plans, and more. Additional offerings include a collection of links mentioned in the series and an internal search engine. This site joins an already strong tradition at PBS of creating sites that are actual companions to the program, offering new and expanded content for interested users.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.sciencenter.org/chemistry/d/findingred.pdf"> <span id="translatedtitle">Finding <span class="hlt">Red</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this chemistry challenge, learners systematically investigate which combination of four solutions produces a deep <span class="hlt">red</span> color. The four solutions are iron(III) chloride, ammonium thiocyanate, tannic acid, and oxalic acid. Background information explains that it is the iron ions in solution combining with ions from the other solutions to create the different colors. After learners discover the different colors, they are encouraged to add a third solution to see if the color can be changed, an example of how chemical equilibrium can be shifted. This activity may take a bit more time with younger learners. For safety reasons, adult supervision is recommended and can be conducted as a demonstration for younger audiences.</p> <div class="credits"> <p class="dwt_author">Sciencenter</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-27</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMEP34C..03C"> <span id="translatedtitle">Morphodynamically-based sediment budget in gravel-<span class="hlt">bed</span> rivers: methodological problems (Invited)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Estimation of the <span class="hlt">bed</span>-material sediment budget from morphological changes has been adopted as an acceptable practice for gravel-<span class="hlt">bed</span> rivers in which trends of morphological change persist for some considerable period. The qualification is important: co-located erosion and deposition within a survey interval biases the result. Another source of significant bias that has not generally been noted is the ';two-speed' nature of the fluvial sediment system by which <span class="hlt">sand</span> moves through a reach much more quickly than gravel. Resident <span class="hlt">sand</span> occurs in particular sedimentary environments (e.g., bar tail) and as cover <span class="hlt">sands</span> - sometimes extensively so - in addition to forming gravel matrix. These materials are readily entrained during high flows and may constitute a large proportion of mobile sediment during flood. Unless explicitly accounted for in end-point assessments, they may significantly bias the gravel budget. Furthermore, they may easily be replaced during a single flood event, introducing the problem of co-located exchange. In Fraser River, British Columbia, a large gravel-<span class="hlt">bed</span> river that appears suitable for sediment budget calculations by morphodynamic methods, an attempt is being made to understand this problem by mapping surficial <span class="hlt">sand</span> using hyperspatial air photography and assessing its volume by application of a distribution of <span class="hlt">sand</span> depths. The volume of these deposits may thereby be separately estimated and discounted in the assessments of changing gravel storage.</p> <div class="credits"> <p class="dwt_author">Church, M. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40675921"> <span id="translatedtitle">Scanning electron microscopy of biofilm formation in denitrifying, fluidised <span class="hlt">bed</span> reactors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Changes in bacterial colonisation on initially clean <span class="hlt">sand</span> grains in an anaerobic fluidised <span class="hlt">bed</span> reactor (FBR) were studied by scanning electron microscopy (SEM). The FBR was part of a laboratory-scale treatment system for nitrate removal from fish culture water. Denitrifying bacteria in the FBR were supplied with anaerobically digested fish feed as carbon and energy source and with nitrate as</p> <div class="credits"> <p class="dwt_author">H. Sich; J. Van Rijn</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=43857"> <span id="translatedtitle">EVALUATION OF ANAEROBIC, EXPANDED-<span class="hlt">BED</span> CONTRACTORS FOR MUNICIPAL WASTEWATER TREATMENT</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">The anaerobic expanded-<span class="hlt">bed</span> contactors for treating dilute municipal wastes were evaluated. A 334-liter diatomaceous earth, a 334 liter granular activated carbon, a set of two 66-liter <span class="hlt">sand</span>, and two 3-liter diatomaceous earth reactor systems were used. For the most part the feed w...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=water+AND+articles&pg=7&id=EJ876165"> <span id="translatedtitle"><span class="hlt">Sand</span> and Water Table Play</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">The authors observed preschoolers engaged at the <span class="hlt">sand</span> and water table to determine if math could be found within their play. Wanting to understand how children interact with provided materials and what kinds of math ideas they explore during these interactions, the authors offer practical examples of how such play can promote mathematical…</p> <div class="credits"> <p class="dwt_author">Wallace, Ann H.; White, Mary J.; Stone, Ryan</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.campusrec.neu.edu/intramurals/rules/Sand%20Volleyball.pdf"> <span id="translatedtitle">NU Intramural Sports <span class="hlt">Sand</span> Volleyball</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">NU Intramural Sports <span class="hlt">Sand</span> Volleyball GENERAL RULES: 1. All players must present their valid be responsible for collecting his team's IDs and registering their uniform numbers with the IM staff. 3. 3 Unsportsmanlike Penalties will result in the player leaving the game. Only a team's designated Captain is allowed</p> <div class="credits"> <p class="dwt_author">Sridhar, Srinivas</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.stevehopkin.co.uk/publications/1998_Ecotoxicology_7_291-295.pdf"> <span id="translatedtitle">Toxicity of nickel to the earthworm and the applicability of the neutral <span class="hlt">red</span> retention assay</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Toxicity of nickel to the earthworm and the applicability of the neutral <span class="hlt">red</span> retention assay JANECK of exposure to a nickel-chloride spiked loamy <span class="hlt">sand</span> soil. The ability of a simple earthworm biomarker-<span class="hlt">red</span> retention time showed large individual variation for the earthworms within each exposure concentration</p> <div class="credits"> <p class="dwt_author">Hopkin, Steve</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40380966"> <span id="translatedtitle">Root system responses of Japanese <span class="hlt">red</span> cedar saplings to acidic conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Stemflow from Japanese <span class="hlt">red</span> cedar (Cryptomeria japonica) enters forest soil at a low pH. We evaluated the responses of the root system of Japanese <span class="hlt">red</span> cedar saplings to acidic conditions, used to simulate this situation, in two different growth media, a brown forest soil (BS) and a Yahagi <span class="hlt">sand</span> (YS). Soils were acidified by the addition of solutions at pH</p> <div class="credits"> <p class="dwt_author">Yasuhiro Hirano; Naoki Hijii</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/218865"> <span id="translatedtitle">Volatiles combustion in fluidized <span class="hlt">beds</span>. Final technical report, 4 September 1992--4 June 1995</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The goal of this project is to investigate the conditions in which volatiles will burn within both the dense and freeboard regions of fluidized <span class="hlt">beds</span>. Experiments using a fluidized <span class="hlt">bed</span> operated at incipient fluidization are being conducted to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized <span class="hlt">bed</span>. A review of the work conducted under this grant is presented in this Final Technical Report. Both experimental and theoretical work have been conducted to examine the inhibition of the combustion by the fluidized <span class="hlt">bed</span> material, <span class="hlt">sand</span>. It has been shown that particulate phase at incipient fluidization inhibits the combustion of propane by free radical destruction at the surface of <span class="hlt">sand</span> particles within the particulate phase. The implications of these findings is that at <span class="hlt">bed</span> temperatures lower than the critical temperatures, gas combustion can only occur in the bubble phase or at the top surface of a bubbling fluidized <span class="hlt">bed</span>. In modeling fluidized <span class="hlt">bed</span> combustion this inhibition by the particulate phase should be included.</p> <div class="credits"> <p class="dwt_author">Pendergrass, R.A. II; Raffensperger, C.; Hesketh, R.P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-02-29</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/wsp/2326b/report.pdf"> <span id="translatedtitle">Sedimentary structures and textures of Rio Orinoco channel <span class="hlt">sands</span>, Venezuela and Colombia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Most sedimentary structures represented in <span class="hlt">sand</span> bodies of the Rio Orinoco are tabular-planar cross-strata which, together with some wedge-planar cross-strata, are the products of <span class="hlt">sand</span>-wave deposition. Locally, in areas of river meander where point bars characteristically form, trough structures forming festoon patterns are numerous. At a few localities, sets of nearly horizontal strata occur between tabular-planar sets and are interpreted to be the deposits of very fast currents of the upper flow regime; elsewhere, uncommon lenses and <span class="hlt">beds</span> of silt, clay, or organic matter consisting of leaves and twigs, seem to be the result of quiet-water settling through gravity. By far the most common grain size represented in the tabular-planar and wedge-planar cross-strata of the sandwave deposits is medium <span class="hlt">sand</span> (? - ? millimeter) as determined by screen analyses. Many samples, however, also contain moderate quantities of coarse or very coarse <span class="hlt">sand</span>. Eolian dunes on top of the <span class="hlt">sand</span>-wave deposits are dominantly fine grained. The river channel <span class="hlt">sands</span> were determined to be largely moderately well sorted, although in some places they were mostly well sorted, and in others, mostly moderately sorted.</p> <div class="credits"> <p class="dwt_author">McKee, Edwin Dinwiddie</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010Geomo.120..224Z"> <span id="translatedtitle">Wind tunnel observation on the effect of a porous wind fence on shelter of saltating <span class="hlt">sand</span> particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A porous wind fence is an artificial barrier widely employed to abate wind erosion. This study investigated the shelter effect of a porous wind fence on saltating <span class="hlt">sand</span> in a simulated atmospheric boundary layer (ABL). A wind fence with a porosity ? = 38.5% was installed on a flat <span class="hlt">bed</span> of <span class="hlt">sand</span> collected from a beach (diameter, d = 200-300 ?m). A high-speed digital camera was used to capture consecutive images of saltating <span class="hlt">sand</span> particles around the fence at a frame rate of 4000 frames per second (fps). In addition, the particle tracking velocimetry (PTV) method was employed to extract the instantaneous velocity fields of saltating <span class="hlt">sand</span> particles. From these data, the mean velocity and volume concentration of saltating <span class="hlt">sand</span>, mass flux, and kinetic energy were evaluated. As a result, the mean velocities decrease dramatically on the leeward side of the fence, and a high-velocity region exists in the shear layer above the fence. The <span class="hlt">sand</span> mass flux distributions with height around the fence are represented by an exponential function. Both the particle concentration and mass flux decay largely in the leeward region. The present experimental results can provide useful information to understand <span class="hlt">sand</span> transport through a porous fence and allow the creation of a new control measure of wind erosion of <span class="hlt">sand</span> particles.</p> <div class="credits"> <p class="dwt_author">Zhang, Ning; Kang, Jong-Hoon; Lee, Sang-Joon</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1990SedG...67..199S"> <span id="translatedtitle">The sedimentology and accretionary styles of an ancient gravel-<span class="hlt">bed</span> stream: the Budleigh Salterton Pebble <span class="hlt">Beds</span> (Lower Triassic), southwest England</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Three accretionary styles are present in the fluvial conglomerates and pebbly sandstones of the Lower Triassic Budleigh Salterton Pebble <span class="hlt">Beds</span> (BSPB) of east Devon. The lower portions of this 20-30 m sequence are dominated by extensive (> 50 m) sheets or narrow lenses of planar cross-<span class="hlt">bedded</span> conglomerate (sets 1-3 m thick). These abruptly pass, both downstream and laterally, into horizontally <span class="hlt">bedded</span> conglomerates, cross-<span class="hlt">bedded</span> sandstones and muddy sandstones. This accretionary style reflects deposition from linguoid-shaped macroforms whose distal margins were bounded by slipfaces. They accreted at anabranch confluences and as bank-attached bars in relatively confined and channelised gravel-<span class="hlt">bed</span> streams. Lateral facies changes represent macroform evolution resulting from changing discharges or abandonment of a channel reach, followed by accretion of a new macroform. The upper portions of the BSPB mainly comprise couplets of horizontally <span class="hlt">bedded</span> conglomerate overlain by large-scale trough cross-<span class="hlt">bedded</span> sandstone. The conglomerate shows local channel-macroform relief and lateral and downstream transitions into sets of gently dipping conglomerate. This style of accretion represents deposition in less confined and less channelised fluvial systems by relatively low-relief gravel macroforms and large <span class="hlt">sand</span> dunes. The third style recognised in the BSPB is much more localised. It consists of wedge-like sets of large-scale trough cross-<span class="hlt">bedded</span> conglomerate. The sets are formed by erosion and subsequent fill of scours cut into a thick sandy substrate. Techniques of lateral profile analysis and hierarchical ordering of bounding surfaces can usefully be applied to some parts of the BSPB. This is important as the approach was originally developed for the deposits of <span class="hlt">sand-bed</span> streams. However, this approach is more difficult to apply to fluvial conglomerates because of the cryptic nature of some gravel stratification. The appearance and character of some hierarchies of bounding surfaces may differ from their equivalents in fluvial sandstones.</p> <div class="credits"> <p class="dwt_author">Smith, Simon A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AIPC.1052..301C"> <span id="translatedtitle">Optimization of Solid Circulation Rate in Compartmented Fluidized <span class="hlt">Bed</span> Gasifier for Power Generation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The present paper reports the optimization of solid circulation rate (SCR) in Compartmented Fluidized <span class="hlt">Bed</span> Gasifier (CFBG), an indirectly heated fluidized <span class="hlt">bed</span> that incorporates two sets of v-valves and risers to control the solid circulation across the two compartments, i.e. combustor and gasifier of a pilot plant scale (the height and ID are 1.8m and 0.66m respectively). <span class="hlt">Sand</span> was used as inert fluidized by air. Four operating variables were studied i.e. <span class="hlt">bed</span> height, riser, v-valve and main <span class="hlt">bed</span> flowrate. Based on 24 full factorial design of experiment in Yates' algorithm, at confidence level ?95%, ANOVA analysis has revealed six important effects. The steepest ascent method was applied on linear regression generated from these effects to design the subsequent optimization experiments. The optimum values of SCR have been estimated for both low and high <span class="hlt">bed</span> level at specific operating parameters.</p> <div class="credits"> <p class="dwt_author">Chok, V. S.; Wee, S. K.; Ariffin, M. Z. Mohd.; Gorin, A.; Chua, H. B.; Yan, H. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1014514"> <span id="translatedtitle">Treating tar <span class="hlt">sands</span> formations with karsted zones</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Methods for treating a tar <span class="hlt">sands</span> formation are described herein. The tar <span class="hlt">sands</span> formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar <span class="hlt">sands</span> formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.</p> <div class="credits"> <p class="dwt_author">Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX)</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-03-09</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a style="font-weight: bold;">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_17");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42239976"> <span id="translatedtitle"><span class="hlt">Sand</span> reinforced with shredded waste tires</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce <span class="hlt">sand</span>. Direct shear tests were conducted on mixtures of dry <span class="hlt">sand</span> and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, <span class="hlt">sand</span> matrix unit weight, shred content, shred length, and shred orientation. From results of</p> <div class="credits"> <p class="dwt_author">Gary J. Foose; Craig H. Benson; Peter J. Bosscher</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1036500"> <span id="translatedtitle">A generalization of Reiner’s mathematical model for wet <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In this paper we modify the constitutive relation derived by Reiner (1945), to describe dilatancy in wet <span class="hlt">sand</span>, by suggesting that the shear viscosity would depend on the shear rate and the volume fraction. We then look at the flow of a saturated densely packed <span class="hlt">bed</span> of particles (with liquid in the pores) between two horizontal flat plates. We obtain exact solutions for a very special case.</p> <div class="credits"> <p class="dwt_author">Mehrdad Massoudi</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.bedandbreakfast.com/"> <span id="translatedtitle">The <span class="hlt">Bed</span> & Breakfast Channel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">With this site, founders Eric and Liz Goldreyer provide travelers with "comprehensive, user-friendly, up-to-date information on <span class="hlt">bed</span> and breakfasts and inns" via the Internet. The primary focus is on providing access to <span class="hlt">bed</span> and breakfast listings in North America (over 20,000), although there is also a growing collection of listings from around the world. In the Quick Search, users may search for accommodations by city, state or country. Users who don't have a specific destination in mind, can browse geographically with the World Search. Basic entries include the name, address, and phone number, as well as a link to a city map. <span class="hlt">Bed</span> and breakfast owners may include additional information, photos, or a link to their own web site, for a fee.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1007/s10236-010-0314-2"> <span id="translatedtitle"><span class="hlt">Bed</span> composition generation for morphodynamic modeling: Case study of San Pablo Bay in California, USA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Applications of process-based morphodynamic models are often constrained by limited availability of data on <span class="hlt">bed</span> composition, which may have a considerable impact on the modeled morphodynamic development. One may even distinguish a period of "morphodynamic spin-up" in which the model generates the <span class="hlt">bed</span> level according to some ill-defined initial <span class="hlt">bed</span> composition rather than describing the realistic behavior of the system. The present paper proposes a methodology to generate <span class="hlt">bed</span> composition of multiple <span class="hlt">sand</span> and/or mud fractions that can act as the initial condition for the process-based numerical model Delft3D. The <span class="hlt">bed</span> composition generation (BCG) run does not include <span class="hlt">bed</span> level changes, but does permit the redistribution of multiple sediment fractions over the modeled domain. The model applies the concept of an active layer that may differ in sediment composition above an underlayer with fixed composition. In the case of a BCG run, the <span class="hlt">bed</span> level is kept constant, whereas the <span class="hlt">bed</span> composition can change. The approach is applied to San Pablo Bay in California, USA. Model results show that the BCG run reallocates <span class="hlt">sand</span> and mud fractions over the model domain. Initially, a major sediment reallocation takes place, but development rates decrease in the longer term. Runs that take the outcome of a BCG run as a starting point lead to more gradual morphodynamic development. Sensitivity analysis shows the impact of variations in the morphological factor, the active layer thickness, and wind waves. An important but difficult to characterize criterion for a successful application of a BCG run is that it should not lead to a <span class="hlt">bed</span> composition that fixes the <span class="hlt">bed</span> so that it dominates the "natural" morphodynamic development of the system. Future research will focus on a decadal morphodynamic hindcast and comparison with measured bathymetries in San Pablo Bay so that the proposed methodology can be tested and optimized. ?? 2010 The Author(s).</p> <div class="credits"> <p class="dwt_author">Van Der Wegen, M.; Dastgheib, A.; Jaffe, B. E.; Roelvink, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6426844"> <span id="translatedtitle">Petroleum geology of East Dykesville field, Smackover C <span class="hlt">sand</span>, Claiborne and Webster Parishes, Louisiana</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The discovery in 1980 of gas production in the Smackover C <span class="hlt">sand</span> in the East Dykesville field of Claiborne and Webster Parishes, Louisiana, extended the productive limits of this reservoir 6 mi (10 km) south of the production in the Haynesville field. The development of East Dykesville field has revealed three productive fault blocks within an area 6 mi (10 km) by 3 mi (5 km). The Smackover C and B <span class="hlt">sand</span> of East Dykesville are present 700 ft (213 m) above the Louann Salt as a portion of a more or less continuous <span class="hlt">sand</span> body covering an area 9 mi (15 km) from east to west. This <span class="hlt">sand</span> body extends southward from the Arkansas-Louisiana state line for more than 10 mi (16 km), and also produces at the Haynesville field. Production has been encountered in the C <span class="hlt">sand</span> at East Dykesville from 10,912 ft (3326 m) subsea down to 11,605 ft (3536 m) subsea, an interval of 693 ft (211 m). The source of the sediments which constitute the Smackover C <span class="hlt">sand</span> appears to be north of the <span class="hlt">sand</span> body, as it thickens to more than 100 ft (31 m) in the <span class="hlt">Red</span> Rock-Haynesville area and thins southward. The <span class="hlt">sand</span> also thins both to the east toward Haynesville and to the west toward Shongaloo. The C <span class="hlt">sand</span> is 60 ft (18 m) thick in the north portion of East Dykesville field and thins to 20 ft (6 m) in the most southern wells. Isopach studies suggest a submarine-fan depositional environment on a stable shelf.</p> <div class="credits"> <p class="dwt_author">Sartor, C.L.; Howard, S.R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830026793&hterms=DRY+FGD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DDRY%2BFGD"> <span id="translatedtitle">Fluidized <span class="hlt">bed</span> coal desulfurization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized <span class="hlt">bed</span> 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 <span class="hlt">bed</span> reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.</p> <div class="credits"> <p class="dwt_author">Ravindram, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/6929142"> <span id="translatedtitle">Staged fluidized <span class="hlt">bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">The invention relates to oil shale retorting and more particularly to staged fluidized <span class="hlt">bed</span> 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 <span class="hlt">beds</span>. 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.</p> <div class="credits"> <p class="dwt_author">Mallon, R.G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-05-13</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/869456"> <span id="translatedtitle">Fluid <span class="hlt">bed</span> material transfer method</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> apparatus comprising a pair of separated fluid <span class="hlt">bed</span> enclosures, each enclosing a fluid <span class="hlt">bed</span> 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 <span class="hlt">bed</span> enclosures and flexibly engaged therewith to communicate the fluid <span class="hlt">beds</span> 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 <span class="hlt">bed</span> enclosures.</p> <div class="credits"> <p class="dwt_author">Pinske, Jr., Edward E. (Akron, OH)</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/866246"> <span id="translatedtitle">Apparatus for controlling fluidized <span class="hlt">beds</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">An apparatus and process for control and maintenance of fluidized <span class="hlt">beds</span> under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized <span class="hlt">bed</span> separate from an ash discharge conduit in the lower portion of the grate supporting such a <span class="hlt">bed</span>. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized <span class="hlt">beds</span> and provides control of the fluidized <span class="hlt">bed</span> before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized <span class="hlt">bed</span> maintenance.</p> <div class="credits"> <p class="dwt_author">Rehmat, Amirali G. (Westmont, IL); Patel, Jitendra G. (Bolingbrook, IL)</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-05-12</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://lithops.as.arizona.edu/~jill/EPO/Stars/StarPower2.pdf"> <span id="translatedtitle"><span class="hlt">Red</span> Giant <span class="hlt">Red</span> Giant White Giant</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Red</span> Giant <span class="hlt">Red</span> Giant White Giant <span class="hlt">Red</span> Giant White Giant White Giant Blue Giant Blue Giant Blue GiantPower Points: 9 The hottest, brightest, and most massive stars. The three stars in Orion's belt, Alnitak, Alnilam and Mintaka, are blue giant stars. Mass: 10 - 70 SM StarPower Points: 10 The hottest, brightest</p> <div class="credits"> <p class="dwt_author">Bechtold, Jill</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18793834"> <span id="translatedtitle">Effects of gasifying conditions and <span class="hlt">bed</span> materials on fluidized <span class="hlt">bed</span> steam gasification of wood biomass.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The effect of steam gasification conditions on products properties was investigated in a bubbling fluidized <span class="hlt">bed</span> reactor, using larch wood as the starting material. For <span class="hlt">bed</span> material effect, calcined limestone and calcined waste concrete gave high content of H(2) and CO(2), while silica <span class="hlt">sand</span> provided the high content of CO. At 650 degrees C, calcined limestone proved to be most effective for tar adsorption and showed high ability to adsorb CO(2) in <span class="hlt">bed</span>. At 750 degrees C it could not capture CO(2) but still gave the highest cold gas efficiency (% LHV) of 79.61%. Steam gasification gave higher amount of gas product and higher H(2)/CO ratio than those obtained with N(2) pyrolysis. The combined use of calcined limestone and calcined waste concrete with equal proportion contributed relatively the same gas composition, gas yield and cold gas efficiency as those of calcined limestone, but showed less attrition, sintering, and agglomeration propensities similar to the use of calcined waste concrete alone. PMID:18793834</p> <div class="credits"> <p class="dwt_author">Weerachanchai, Piyarat; Horio, Masayuki; Tangsathitkulchai, Chaiyot</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/6136211"> <span id="translatedtitle">Conservation and management of northeast Atlantic and Mediterranean maerl <span class="hlt">beds</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">ABSTRACT 1. Maerl <span class="hlt">beds</span> occur worldwide,and are formed,by an accumulation,of unattached,calcareous <span class="hlt">red</span> algae (Rhodophyta). 2. Maerl-forming algae grow,in a superficial living layer on sediments,within the photic zone. 3. Maerl <span class="hlt">beds</span> are spatially complex,habitats with a high degree of species and,trophic group diversity. 4. The European,Commission’s ‘Habitats Directive’ mandates,the conservation,management,of two of the main European maerl-forming species, Phymatolithon calcareum and Lithothamnion</p> <div class="credits"> <p class="dwt_author">C. Barbera; C. Bordehore; J. A. Borg; J. Grall; J. M. Hall-Spencer; Ch. de la Huz; E. Lanfranco; M. Lastra; P. G. Moore; J. Mora; M. E. Pita; M. Rizzo; A. Seva; P. J. Schembri; C. Valle</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://innovation.ucdavis.edu/people/publications/Biagioli_Difference_Blackboxing.pdf"> <span id="translatedtitle">Sylvere Lotringer and <span class="hlt">Sande</span> Cohen</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">in her <span class="hlt">bed</span>. She was known for her chain-smoking-a smolderingcigarette caused the fatal fire. From Difference to Blackboxing: French Theory versus Science Studies' Metaphysics of Presence MARIO ambivalence. The Peculiarity of Science Studies Sciencestudiesis a looselystructured fieldthat looksat</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMMR13A2274L"> <span id="translatedtitle">Thermal Properties of oil <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Thermal recovery methods such as Cyclic Steam Injection or Steam Assisted Gravity Drainage (SAGD) are the effective methods for producing heavy oil or bitumen. In any thermal recovery methods, thermal properties (e.g., thermal conductivity, thermal diffusivity, and volumetric heat capacity) are closely related to the formation and expansion of steam chamber within a reservoir, which is key factors to control efficiency of thermal recovery. However, thermal properties of heavy oil or bitumen have not been well-studied despite their importance in thermal recovery methods. We measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of 43 oil <span class="hlt">sand</span> samples from Athabasca, Canada, using a transient thermal property measurement instrument. Thermal conductivity of 43 oil <span class="hlt">sand</span> samples varies from 0.74 W/mK to 1.57 W/mK with the mean thermal conductivity of 1.09 W/mK. The mean thermal diffusivity is 5.7×10-7 m2/s with the minimum value of 4.2×10-7 m2/s and the maximum value of 8.0×10-7 m2/s. Volumetric heat capacity varies from 1.5×106 J/m3K to 2.11×106 J/m3K with the mean volumetric heat capacity of 1.91×106 J/m3K. In addition, physical and chemical properties (e.g., bitumen content, electric resistivity, porosity, gamma ray and so on) of oil <span class="hlt">sand</span> samples have been measured by geophysical logging and in the laboratory. We are now proceeding to investigate the relationship between thermal properties and physical/chemical properties of oil <span class="hlt">sand</span>.</p> <div class="credits"> <p class="dwt_author">LEE, Y.; Lee, H.; Kwon, Y.; Kim, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20000025355&hterms=single+parent&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dsingle%2Bparent"> <span id="translatedtitle">Behavior of Windblown <span class="hlt">Sand</span> on Mars: Results from Single-Particle Experiments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Experiments are investigating the behavior of individual <span class="hlt">sand</span> grains in the high-energy martian aeolian regime. Energy partitioning during impact of a saltating grain determines grain longevity, but it also influences the way in which the <span class="hlt">bed</span> becomes mobilized by reptation. When single grains of <span class="hlt">sand</span> are fired into loose <span class="hlt">beds</span>, the <span class="hlt">bed</span> can absorb up to 90% of the impact energy by momentum transfer to other grains; it has been discovered that the impacting grains cause circular craters even at low impact angles. Hundreds of grains can be splashed by a single high-velocity (100 m/s) impact causing more <span class="hlt">bed</span> disturbance through reptation than previously thought. The research is supported by NASA's PG&G Program. Because the martian aeolian environment in both high energy and of long duration, the most mobile fractions of windblown <span class="hlt">sand</span> should have eradicated themselves by attrition, unless <span class="hlt">sand</span> supply has kept pace with destruction. It is therefore important to understand the rate of grain attrition in order to make sense of the existence of vast dune fields on Mars. Attrition, has been addressed in other studies, but precise data for a single saltating grain striking a loose <span class="hlt">bed</span> of <span class="hlt">sand</span> have not been acquired -- the quintessential case to be understood for dunes on Mars. To acquire these data, we are employing a compound crossbow which has the bolt-firing mechanism replaced with a pneumatically-automated sabot system. The sabot can launch individual grains of <span class="hlt">sand</span> of any size between several millimeters and about 50 microns, at velocities up to 100m/s. This is around the maximum velocity expected for saltating grains on Mars. The sabot sled is equipped with photoelectric sensors for measuring shot velocity. Baffling of the grain's exit orifice has enabled projection of single grains without significant aerodynamic effects from the sabot. Grains are fired into loose <span class="hlt">beds</span> of <span class="hlt">sand</span> at about 15 degrees from the horizontal (typical saltation trajectory at impact) while being filmed on high-speed video. High-intensity pulse illumination for the grains is triggered by the solenoid-operated bow trigger. A 45 degree mirror over the impact site provides simultaneous horizontal and vertical images of the impact on each video frame. UV fluorescence is enabling grain and grain-fragment recovery. At 100 m/s, grains of all sizes shatter into many fragments when the <span class="hlt">sand</span> is replaced with a solid target. Kinetic energy of the grains at this velocity exceeds the critical energy for catastrophic failure of minerals. Although probably exceptional as a grain speed, it suggests that conditions on Mars might elevate materials into an attrition regime not encountered on other planets; individual grains blown across rock pavements on Mars will have short lifespans. When experimental grains impact loose (dune) <span class="hlt">sand</span>, much, if not most of the kinetic energy is converted into momentum of other grains. Using high-speed filming, the energy involved in splashing grains at the impact site can be derived from the size of the crater, the speed of the splashed grains, and the rebound speed of the impactor. The amount of energy partitioned into material failure (as opposed to momentum) is too small a fraction of the total to be calculated under these circumstances. This does not necessarily mean that little damage occurs to the grains (the full extent of the damage has yet to be determined) because only a small fraction of the impact energy is required for inducing brittle fracture. Damage is orders of magnitude less than during impact against solid surfaces.</p> <div class="credits"> <p class="dwt_author">Marshall, J. R.; Borucki, J.; Sagan, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040173037&hterms=Oxygen+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DOxygen%2Bconsumption"> <span id="translatedtitle">Cardiovascular consequences of <span class="hlt">bed</span> rest: effect on maximal oxygen uptake</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Maximal oxygen uptake (VO2max) is reduced in healthy individuals confined to <span class="hlt">bed</span> rest, suggesting it is independent of any disease state. The magnitude of reduction in VO2max is dependent on duration of <span class="hlt">bed</span> rest and the initial level of aerobic fitness (VO2max), but it appears to be independent of age or gender. <span class="hlt">Bed</span> rest induces an elevated maximal heart rate which, in turn, is associated with decreased cardiac vagal tone, increased sympathetic catecholamine secretion, and greater cardiac beta-receptor sensitivity. Despite the elevation in heart rate, VO2max is reduced primarily from decreased maximal stroke volume and cardiac output. An elevated ejection fraction during exercise following <span class="hlt">bed</span> rest suggests that the lower stroke volume is not caused by ventricular dysfunction but is primarily the result of decreased venous return associated with lower circulating blood volume, reduced central venous pressure, and higher venous compliance in the lower extremities. VO2max, stroke volume, and cardiac output are further compromised by exercise in the upright posture. The contribution of hypovolemia to reduced cardiac output during exercise following <span class="hlt">bed</span> rest is supported by the close relationship between the relative magnitude (% delta) and time course of change in blood volume and VO2max during <span class="hlt">bed</span> rest, and also by the fact that retention of plasma volume is associated with maintenance of VO2max after <span class="hlt">bed</span> rest. Arteriovenous oxygen difference during maximal exercise is not altered by <span class="hlt">bed</span> rest, suggesting that peripheral mechanisms may not contribute significantly to the decreased VO2max. However reduction in baseline and maximal muscle blood flow, <span class="hlt">red</span> blood cell volume, and capillarization in working muscles represent peripheral mechanisms that may contribute to limited oxygen delivery and, subsequently, lowered VO2max. Thus, alterations in cardiac and vascular functions induced by prolonged confinement to <span class="hlt">bed</span> rest contribute to diminution of maximal oxygen uptake and reserve capacity to perform physical work.</p> <div class="credits"> <p class="dwt_author">Convertino, V. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=41973"> <span id="translatedtitle">ELECTRIFIED <span class="hlt">BED</span> EVALUATION</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">The report gives results of an evaluation of a prototype electrified <span class="hlt">bed</span> (EFB) particulate collection device. The 500 cfm unit, which uses mechanical and electrical mechanisms for collection, was installed at an asphalt roofing plant during the tests. Fractional efficiency was de...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=33088"> <span id="translatedtitle">EXPANDED <span class="hlt">BED</span> BIOLOGICAL TREATMENT</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">A three-year pilot-scale research investigation at the EPA Lebanon Pilot Plant was conducted to evaluate the feasibility of a unique biological secondary treatment process, designated the Expanded <span class="hlt">Bed</span> Biological Treatment Process (EBBT). The EBBT process is a three-phase (oxygen/...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/09_10_2009_cg8Jam4YYt_09_10_2009_5"> <span id="translatedtitle">Pliocene Lignite <span class="hlt">Bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">Seam or <span class="hlt">bed</span> of Pliocene lignite from a mine in the Balkan endemic nephropathy (BEN) area of Romania. Rainwater falling onto the surface penetrates into the ground, becoming ground water, and leaches toxic organic substances from this coal. The ground water continues to BEN villages in the valleys be...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-09-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.H52A..04T"> <span id="translatedtitle">Using high-resolution suspended-sediment measurements to infer changes in the topographic distribution and grain size of <span class="hlt">bed</span> sediment in the Colorado River downstream from Glen Canyon Dam</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Eddy sandbars and other sandy deposits in and along the Colorado River in Grand Canyon National Park (GCNP) were an integral part of the pre-dam riverscape, and are still important for habitat, protection of archeological sites, and recreation. Recent work has shown that eddy bars are dynamic landforms and represent the bulk of the ecosystem's <span class="hlt">sand</span> reserves. These deposits began eroding following the 1963 closure of Glen Canyon Dam that reduced the supply of <span class="hlt">sand</span> at the upstream boundary of GCNP by about 94% and are still eroding today. <span class="hlt">Sand</span> transport in the post-dam river is limited by episodic resupply from tributaries, and is equally regulated by the discharge of water and short-term changes in the grain size of <span class="hlt">sand</span> available for transport (Rubin and Topping, WRR, 2001). During tributary floods, <span class="hlt">sand</span> on the <span class="hlt">bed</span> of the Colorado River fines; this causes the suspended <span class="hlt">sand</span> to fine and the suspended-<span class="hlt">sand</span> concentration to increase even when the discharge of water remains constant. Subsequently, the <span class="hlt">bed</span> is winnowed of finer <span class="hlt">sand</span>, the suspended <span class="hlt">sand</span> coarsens, and the suspended-<span class="hlt">sand</span> concentration decreases independently of discharge. This prohibits the computation of <span class="hlt">sand</span>-transport rates in the Colorado River using stable relations between water discharge and <span class="hlt">sand</span> transport (i.e., sediment rating curves) and requires a more continuous method for measuring <span class="hlt">sand</span> transport. To monitor suspended sediment at higher (i.e., 15-minute) resolutions, we began testing a laser-acoustic system at four locations along the Colorado River in Grand Canyon in August 2002. Because they are much easier to acquire, the high-resolution suspended-sediment datasets collected using the laser-acoustic systems greatly outnumber (by >5 orders of magnitude) direct grain-size measurements of the upstream <span class="hlt">bed</span> sediment. Furthermore, suspension processes effectively provide an average "sample" of the <span class="hlt">bed</span> sediment on the perimeter of the upstream channel and the underwater portions of the banks and eddy bars. Thus, it is advantageous to analyze suspended-sediment concentration and grain-size data to infer changes in the topographic distribution and grain size of the upstream <span class="hlt">bed</span> sediment. Rubin and Topping (2001) developed and tested a theory-based technique that can be used for this purpose. Their parameter "? " is a nondimensional measure of the average <span class="hlt">bed</span>-surface grain-size that interacts with the suspended sediment in the flow. Analyses of the laser-acoustic datasets indicate that, when the Colorado River is relatively enriched with respect to finer <span class="hlt">sand</span>, the discharge of water, and the concentration and grain size of the suspended <span class="hlt">sand</span> are all positively correlated. During these periods, ? is negatively correlated with discharge, indicating that the <span class="hlt">sand</span> on the <span class="hlt">bed</span> is finer at higher elevations along the banks. Although water discharge and the concentration of suspended <span class="hlt">sand</span> remain positively correlated when the river is relatively depleted in finer <span class="hlt">sand</span>, grain size of suspended <span class="hlt">sand</span> then becomes negatively correlated with both the discharge of water and suspended-<span class="hlt">sand</span> concentration. The greater decrease in ? as a function of discharge demonstrates the decrease in the grain size of the <span class="hlt">bed</span> <span class="hlt">sand</span> as a function of elevation is much greater under <span class="hlt">sand</span>-depleted conditions than under <span class="hlt">sand</span>-enriched conditions. Thus, these analyses indicate that, during periods of erosion, <span class="hlt">sand</span> is winnowed preferentially from lower elevations along the river.</p> <div class="credits"> <p class="dwt_author">Topping, D. J.; Rubin, D. M.; Melis, T. S.; Wright, S. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA07831&hterms=Arabic+Arabic+al-+arab+yah&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DArabic%2B%257C%2B%25D8%25A7%25D9%2584%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%25D8%25A9%2B%257C%2Bal-%25CA%25BBarab%25C4%25AByah%2B%257C%2B%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%252F%2526"> <span id="translatedtitle"><span class="hlt">Sand</span> Sheet on Crater Floor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">[figure removed for brevity, see original site] <p/> Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar <span class="hlt">sand</span> sea and at isolated dune fields at lower latitudes. <span class="hlt">Sand</span> seas on Earth are often called 'ergs,' an Arabic name for dune field. A <span class="hlt">sand</span> sea differs from a dune field in two ways: 1) a <span class="hlt">sand</span> sea has a large regional extent, and 2) the individual dunes are large in size and complex in form. <p/> As with yesterday's image, this dune field is located inside a crater, in this case an unnamed crater at 26 degrees North latitude. In this VIS image the dunes are coalescing into a <span class="hlt">sand</span> sheet, note the lack of dune forms to the north of the small hills. The presence of ridges and hills in the area is affecting the dune shapes. <p/> Image information: VIS instrument. Latitude 26.4, Longitude 62.7 East (297.3 West). 19 meter/pixel resolution. <p/> Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. <p/> NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/47736150"> <span id="translatedtitle">The Role of Rhodolith <span class="hlt">Beds</span> in the Recruitment of Invertebrate Species from the Southwestern Gulf of California, Mexico</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">\\u000a Rhodoliths are free-living forms of non-geniculated coralline <span class="hlt">red</span> algae (Corallinaceae, Rhodophyta) that form extensive <span class="hlt">beds</span>\\u000a worldwide over broad latitudinal and depth ranges (Foster, 2001). Synonymous with the maerl <span class="hlt">beds</span> common in the northeastern\\u000a Atlantic, rhodolith <span class="hlt">beds</span> are hard benthic substrates, although mobile, made up of branching crustose coralline thalli. Collectively,\\u000a they create a fragile biogenic matrix over carbonate sediment deposits</p> <div class="credits"> <p class="dwt_author">Rafael Riosmena-Rodriguez; Marco A. Medina-L?pez</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48101041"> <span id="translatedtitle">The Role of Rhodolith <span class="hlt">Beds</span> in the Recruitment of Invertebrate Species from the Southwestern Gulf of California, México</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">\\u000a Rhodoliths are free-living forms of nongeniculate coralline <span class="hlt">red</span> algae (Corallinaceae, Rhodophyta) that form extensive <span class="hlt">beds</span>\\u000a worldwide over broad latitudinal and depth ranges (Foster, 2001). Synonymous with the maerl <span class="hlt">beds</span> common in the northeastern\\u000a Atlantic, rhodolith <span class="hlt">beds</span> are hard benthic substrates, albeit mobile, made up of branching crustose coralline thalli. Collectively,\\u000a they create a fragile biogenic matrix over carbonate sediment deposits</p> <div class="credits"> <p class="dwt_author">Rafael Riosmena-Rodriguez; Marco A. Medina-López</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22702484"> <span id="translatedtitle">Co-firing of sugar cane bagasse with rice husk in a conical fluidized-<span class="hlt">bed</span> combustor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper presents experimental results on co-firing of ‘as-received’ sugar cane bagasse and rice husk in a conical fluidized-<span class="hlt">bed</span> combustor (FBC) using silica <span class="hlt">sand</span> as the <span class="hlt">bed</span> material. Axial temperature, O2, CO2, CO and NO concentration profiles in the conical FBC operated at 82.5–82.8kg\\/h fuel feed rate and various values of excess air (of about 40, 60, 80 and 100%)</p> <div class="credits"> <p class="dwt_author">V. I. Kuprianov; K. Janvijitsakul; W. Permchart</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA06742&hterms=migration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmigration"> <span id="translatedtitle">DCS of Syrtis Major <span class="hlt">Sand</span> Migration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">[figure removed for brevity, see original site] <p/> Released August 2, 2004 This image shows two representations of the same infra-<span class="hlt">red</span> image of craters and lava flow features in Syrtis Major. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations. <p/> The prominent rim of the large crater at the top of the image is blocking migrating <span class="hlt">sand</span> from entering the crater. This produces a very distinct compositional boundary between the pink/magenta basaltic <span class="hlt">sand</span> and the green dust covering the crater rim and floor. Many of the smaller craters in this region have dust trails behind them, indicating the prevailing wind direction. At the top of the image, the prevailing wind direction is to the northwest, while at the bottom of the image, the prevailing winds have shifted towards the southwest. <p/> Image information: IR instrument. Latitude 9.2, Longitude 68.4 East (291.6 West). 100 meter/pixel resolution. <p/> Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. <p/> NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19700000283&hterms=adsorption+silica+gel&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dadsorption%2B%2522silica%2Bgel%2522"> <span id="translatedtitle">Design method for adsorption <span class="hlt">beds</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Regenerable adsorption <span class="hlt">beds</span> for long-term life support systems include synthetic geolite to remove carbon dioxide and silica gel to dehumidify the atmospheric gas prior to its passage through the geolite <span class="hlt">beds</span>. <span class="hlt">Bed</span> performance is evaluated from adsorption characteristics, heat and mass transfer, and pressure drop.</p> <div class="credits"> <p class="dwt_author">Blakely, R. L.; Jackson, J. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1970-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23745431"> <span id="translatedtitle">[Environmental toxicity of waste foundry <span class="hlt">sand</span>].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The metal leaching characteristics and volatile organic compounds (VOCs) of five different types of waste foundry <span class="hlt">sands</span> were analyzed with the toxicity characteristic leaching procedure (TCLP) and head space-gas chromatography (HS-GC). Microtox and soil dehydrogenase activity (DHA) tests were then used to evaluate the bio-effects of these waste <span class="hlt">sands</span>. The results showed that due to the different metals poured and casting materials used to make the <span class="hlt">sand</span> molds, there was significant difference among the five waste foundry <span class="hlt">sands</span> in the compositions and concentrations of metal and organic pollutants. The concentrations of Fe in the leachates of iron and steel casting waste foundry <span class="hlt">sand</span> exceeded the maximal allowable concentrations specified in the National Standard of Drinking Water Quality, whereas the As concentration in the leachate of aluminum casting waste foundry <span class="hlt">sand</span> exceeded the standard. The five waste foundry <span class="hlt">sands</span> had quite different compositions and levels of VOCs, which resulted in different levels of inhibition effects on the luminescent bacteria (30% and 95%). Additionally, the soil DHA tests suggested that metal pollutants in waste foundry <span class="hlt">sands</span> may inhibit the soil microbial activity, whereas organics in the <span class="hlt">sands</span> may slightly promote the microbial activity. The results of this study indicated that the waste foundry <span class="hlt">sands</span> may pose considerable threat to the environment when improperly disposed. PMID:23745431</p> <div class="credits"> <p class="dwt_author">Zhang, Hai-Feng; Wang, Yu-Jue; Wang, Jin-Lin; Huang, Tian-You; Xiong, Ying</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014NatGe...7..350N"> <span id="translatedtitle"><span class="hlt">Sand</span> as a stable and sustainable resource for nourishing the Mississippi River delta</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Mississippi River delta is undergoing a catastrophic drowning, whereby 5,000 km2 of low-lying wetlands have converted to open water over at least the past eight decades, as a result of many anthropogenic and natural factors. Continued net land loss has been thought inevitable due to a decline in the load of total suspended sediment--both <span class="hlt">sand</span> and mud--carried by the river. However, <span class="hlt">sand</span>--which accounts for ~50-70% of modern and ancient Mississippi delta deposits but comprises only ~20% of the sampled portion of the total load--could be more important than mud for subaerial delta growth. Historically, half of the Mississippi River sediment load is supplied by the Missouri River. Here we analyse suspended sediment load data from two locations downstream from the lowest Missouri River dam to show that the measured <span class="hlt">sand</span> load in the lower 1,100 km of the Mississippi River has not significantly diminished since dam construction. A one-dimensional numerical model of river morphodynamics predicts that the <span class="hlt">sand</span> load feeding the delta will decrease only gradually over the next several centuries, with an estimated decline from current values of no more than about 17% within the coming six centuries. We conclude that the lower Mississippi River channel holds a significant reservoir of <span class="hlt">sand</span> that is available to replenish diminished loads via <span class="hlt">bed</span> scour and substantially mitigate land loss.</p> <div class="credits"> <p class="dwt_author">Nittrouer, Jeffrey A.; Viparelli, Enrica</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014DPS....4611502B"> <span id="translatedtitle">Production Mechanisms for the <span class="hlt">Sand</span> on Titan and the Prospects for a Global <span class="hlt">Sand</span> Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">With ~15% of its surface covered by <span class="hlt">sand</span> seas, Titan turns out to be the Arrakis of the solar system. How the <span class="hlt">sand</span> particles that make up the dunes are created, however, remains an outstanding question. Titan's haze particles are organic in composition as required by spectral analysis of dunes, however they have diameters of ~1um, and are 10,000,000 times too small by mass to directly represent the ~200-um <span class="hlt">sand</span> particles. In addition to previous suggestions that <span class="hlt">sand</span> could come from sintering of <span class="hlt">sand</span> particles or by burial, lithification, and subsequent erosion (more like typical <span class="hlt">sands</span> on Earth), we suggest two new mechanisms for production of <span class="hlt">sand</span> in association with Titan's liquid reservoirs. Dissolution and reprecipitation as evaporite forms the gypsum dunes of White <span class="hlt">Sands</span>, NM, USA on Earth, and could play a role on Titan as well. Alternatively, haze particles in the lakes and seas could aggregate into larger particles via flocculation, a mechanism seen to occur on Earth in Morocco. Each of these <span class="hlt">sand</span> particle production ideas has associated predictions that can be tested by future observations. The lack of evident <span class="hlt">sand</span> sources in VIMS data implies that Titan's <span class="hlt">sand</span> seas may be old and their continuous interconnectedness across the Dark Equatorial Belt implies that all of the equatorial dunefields may represent a single compositionally uniform <span class="hlt">sand</span> sea. We will present possibilities for <span class="hlt">sands</span> from this sea to bridge the large gap across Xanadu, including barchan chains and fluvial transport.</p> <div class="credits"> <p class="dwt_author">Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; MacKenzie, Shannon</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998Geomo..22..113S"> <span id="translatedtitle">Wind-blown <span class="hlt">sand</span> on beaches: an evaluation of models</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Five models for predicting rates of aeolian <span class="hlt">sand</span> transport were evaluated using empirical data obtained from field experiments conducted in April, 1994 at a beach on Inch Spit, Co. Kerry, Republic of Ireland. Measurements were made of vertical wind profiles (to derive shear velocity estimates), beach slope, and rates of <span class="hlt">sand</span> transport. Sediment samples were taken to assess characteristics of grain size and surface moisture content. Estimates of threshold shear velocity were derived using grain size data. After parsing the field data on the basis of the quality of shear velocity estimation and the occurrence of blowing <span class="hlt">sand</span>, 51 data sets describing rates of <span class="hlt">sand</span> transport and environmental conditions were retained. Mean grain diameter was 0.17 mm. Surface slopes ranged from 0.02 on the foreshore to about 0.11 near the dune toe. Mean shear velocities ranged from 0.23 m s -1 (just above the observed transport threshold) to 0.65 m s -1. Rates of transport ranged from 0.02 kg m -1 h -1 to more than 80 kg m -1 h -1. These data were used as input to the models of Bagnold [Bagnold, R.A., 1936. The Movement of Desert <span class="hlt">Sand</span>. Proc. R. Soc. London, A157, 594-620], Kawamura [Kawamura, R., 1951. Study of <span class="hlt">Sand</span> Movement by Wind. Translated (1965) as University of California Hydraulics Engineering Laboratory Report HEL 2-8, Berkeley], Zingg [Zingg, A.W., 1953. Wind tunnel studies of the movement of sedimentary material. Proc. 5th Hydraulics Conf. Bull. 34, Iowa City, Inst. of Hydraulics, pp. 111-135], Kadib [Kadib, A.A., 1965. A function for <span class="hlt">sand</span> movement by wind. University of California Hydraulics Engineering Laboratory Report HEL 2-8, Berkeley], and Lettau and Lettau [Lettau, K. and Lettau, H., 1977. Experimental and Micrometeorological Field Studies of Dune Migration. In: K. Lettau and H. Lettau (Eds.), Exploring the World's Driest Climate. University of Wisconsin-Madison, IES Report 101, pp. 110-147]. Correction factors to adjust predictions of the rate of transport to account for the effects of slope and moisture content were calculated using the models of Bagnold [Bagnold, R.A., 1973. The nature of saltation and '<span class="hlt">bed</span>-load' transport in water. Proc. R. Soc. London, Ser. A, 332, 473-504] and Belly [Belly, P.-Y., 1964. <span class="hlt">Sand</span> movement by wind. U.S. Army Corps Eng. CERC. Tech. Mem. 1, Washington D.C., 38 pp.], respectively. None of the models was able to produce a strong correspondence between measured and predicted rates of transport. Best results were obtained using the Bagnold and Zingg models, and the Kadib model was the least viable of this group. The influence of sediment moisture content appeared to be the critical factor in degrading model viability. Overall, none of the models is adequate for general applications to coastal-aeolian environments where moisture content complications tend to override the predictive competence of the simple transport formulations.</p> <div class="credits"> <p class="dwt_author">Sherman, Douglas J.; Jackson, Derek W. T.; Namikas, Steven L.; Wang, Jinkang</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001IJNAM..25..789P"> <span id="translatedtitle">Volumetric <span class="hlt">sand</span> production model and experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A <span class="hlt">sand</span> production model was developed for volumetric <span class="hlt">sand</span> production predictions that take into account the effects of the external stresses and fluid flow rate. The model couples the poro-mechanical behaviour of the solid-fluid system with the erosion behaviour of the solids due to fluid flow. It predicts reasonably experimental volumetric <span class="hlt">sand</span> production data from a hollow cylinder test on a weak sandstone. The test results show that in weak and compactive sandstones, <span class="hlt">sand</span> production is associated with decohesioning and plasticification of a zone around the inner hole which can then be mobilized by the hydrodynamic forces of the fluid flow. The <span class="hlt">sand</span> production rate increases both with external applied stress and fluid flow rate but it is constant with time under constant external stress and fluid flow rate. In both cases a critical lower limit has to be exceeded for <span class="hlt">sand</span> production initiation.</p> <div class="credits"> <p class="dwt_author">Papamichos, E.; Vardoulakis, I.; Tronvoll, J.; Skjærstein, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003JOUC....2..207S"> <span id="translatedtitle">Liquefaction of <span class="hlt">sand</span> under low confining pressure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Undrained behaviour of <span class="hlt">sand</span> under low cell pressure was studied in static and cyclic triaxial tests. It was found that very loose <span class="hlt">sand</span> liquefies under static loading with the relative density being a key parameter for the undrained behaviour of <span class="hlt">sand</span>. In cyclic triaxial tests, pore water pressures built up during the cyclic loading and exceeded the confining cell pressure. this process was accompanied by a large sudden increase in axial deformation. The necessary number of cycles to obtain liquefaction was related to the confining cell pressure, the amplitude of cyclic loading and the relative density of <span class="hlt">sand</span>. In addition, the patterns of pore water pressure response are different from those of <span class="hlt">sand</span> samples with different relative densities. The test results are very useful for expounding scour mechanism around coastal structures since they relate to the low stress behaviour of the <span class="hlt">sand</span>.</p> <div class="credits"> <p class="dwt_author">Shaoli, Yang; Sandven, Rolf; Grande, Lars</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/865235"> <span id="translatedtitle">Staged fluidized <span class="hlt">bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">Method and apparatus for narrowing the distribution of residence times of any size particle and equalizing the residence times of large and small particles in fluidized <span class="hlt">beds</span>. 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.</p> <div class="credits"> <p class="dwt_author">Mallon, Richard G. (Livermore, CA)</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ldeo.columbia.edu/~polsen/nbcp/et-touhami_mapg_07_sm.pdf"> <span id="translatedtitle">Tectonostratigraphy, Biostratigraphy, and Magnetostratigraphy of Late Triassic-Early Jurassic <span class="hlt">Red</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Tectonostratigraphy, Biostratigraphy, and Magnetostratigraphy of Late Triassic-Early Jurassic <span class="hlt">Red</span> Brook Street, Box 1846, Providence Rl 02912, USA Late Triassic-Early Jurassic predominately continental <span class="hlt">red</span> <span class="hlt">beds</span> formed during the Triassic/Jurassic rifting of Pangeacrop out over large portions of northern</p> <div class="credits"> <p class="dwt_author">Olsen, Paul E.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFMOS31A1630B"> <span id="translatedtitle">An Objective Approach for Defining Reference <span class="hlt">Bed</span> Load Transport Rates in Gravel-<span class="hlt">Bed</span> River</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Previous studies have described three phases of <span class="hlt">bed</span> load transport in armored gravel-<span class="hlt">bed</span> rivers, though any given river might not demonstrate all three phases. First, selective transport of the most easily mobilized grains over a largely immobile armor layer during low flows (Phase I, supply-limited transport of fine sediment and medium-sized particles of high protrusion and low friction angle). Second, partial transport of the armor layer as the flow increases (Phase II, transport-limited motion that depends on the spatial variation of both armoring and boundary shear stress, and thus the extent of the <span class="hlt">bed</span> that can be mobilized). Finally, active transport of the majority of the armor layer at high discharge (Phase III, supply-limited transport, representing near-complete activation of the <span class="hlt">bed</span> area and underlying sediment supply as modulated by the armor). Here, we use a piecewise regression similar to that of Ryan et al. [2002] for objectively identifying transitions between phases of <span class="hlt">bed</span> load transport within a framework of dimensionless transport rate (W*) versus Shields stress (?*) [Parker et al., 1982]. The approach is applied to data sets from Oak Creek, Oregon, and the East Fork River, Wyoming, providing contrasting physical conditions and transport processes; Oak Creek is a well-armored gravel channel that exhibits Phase I and II transport, while the East Fork River is a poorly- armored, <span class="hlt">sand</span>-gravel channel that exhibits Phase II and III transport. We find that phase transitions vary by size class and that equal mobility of a given size class (defined as pi/fi ~ 1, the proportion of a size class in the <span class="hlt">bed</span> load relative to that of the subsurface [Wilcock and McArdell, 1993; Church and Hassan, 2002]) can occur during all phases of transport as the source and composition of the sediment supply change (i.e., mobilization of textural patches, banks, etc.) and as a numerical consequence of the degree of motion of other size classes. Our approach also provides a physical basis for defining size-specific reference transport rates (W*ri) at the transition from Phase I to II transport, and we test the performance of the Parker [1990] equation with this new definition of W*ri.</p> <div class="credits"> <p class="dwt_author">Barry, J. J.; Buffington, J. M.; Goodwin, P.; King, J. G.; Emmett, W. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011EurSS..44...13P"> <span id="translatedtitle">Genetic features of soils on marine <span class="hlt">sands</span> and their windblown derivatives on the White Sea coast (the Kola Peninsula)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Quaternary deposits on the Tersk coast of the White Sea are represented by marine deposits (the Tersk <span class="hlt">sands</span>) enriched in the sea-sorted eluvium of the <span class="hlt">red</span> Tersk sandstone. These deposits and the soils developed from them are characterized by the predominance of the fine <span class="hlt">sand</span> fraction and the absence of gravel and the coarser fractions. The sediments derived from the <span class="hlt">red</span> Tersk sandstone have an impoverished chemical composition (the silica content reaches 75-80%). The iron-illuvial podzols developed from them are characterized by the slightly pronounced differentiation of the main oxides and by the eluvial-illuvial redistribution of the amorphous Al and Fe compounds. Sandy soils—psammozems—with undifferentiated soil profiles are developed from windblown <span class="hlt">sands</span> subjected to afforestation and from coastal marine <span class="hlt">sands</span> under a relatively thin natural plant cover. Iron-illuvial podzols buried under a thin <span class="hlt">sand</span> layer preserve the Al-Fe-humus type of the profile differentiation. In the recently deposited <span class="hlt">sand</span> layer, the eluvial-illuvial redistribution of the chemical elements is absent.</p> <div class="credits"> <p class="dwt_author">Pereverzev, V. N.; Kazakov, L. A.; Chamin, V. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/87819"> <span id="translatedtitle">Onsite Wastewater Treatment Systems: <span class="hlt">Sand</span> Filters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">the incoming wastewater; ? Chemical sorption, in which contaminants stick to the surface of the <span class="hlt">sand</span> and to the biological growth on the <span class="hlt">sand</span> surface; and ? Assimilation, in which aerobic microbes eat the nutrients in the wastewater. The success of treat...- ing wastewater depends on these microbes. Air must be available for these microbes to live. <span class="hlt">Sand</span> filters are often partially or completely buried in the ground, but may be built above ground where there is a high water table or bedrock...</p> <div class="credits"> <p class="dwt_author">Lesikar, Bruce J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70047827"> <span id="translatedtitle">Visual accumulation tube for size analysis of <span class="hlt">sands</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The visual-accumulation-tube method was developed primarily for making size analyses of the <span class="hlt">sand</span> fractions of suspended-sediment and <span class="hlt">bed</span>-material samples. Because the fundamental property governing the motion of a sediment particle in a fluid is believed to be its fall velocity. the analysis is designed to determine the fall-velocity-frequency distribution of the individual particles of the sample. The analysis is based on a stratified sedimentation system in which the sample is introduced at the top of a transparent settling tube containing distilled water. The procedure involves the direct visual tracing of the height of sediment accumulation in a contracted section at the bottom of the tube. A pen records the height on a moving chart. The method is simple and fast, provides a continuous and permanent record, gives highly reproducible results, and accurately determines the fall-velocity characteristics of the sample. The apparatus, procedure, results, and accuracy of the visual-accumulation-tube method for determining the sedimentation-size distribution of <span class="hlt">sands</span> are presented in this paper.</p> <div class="credits"> <p class="dwt_author">Colby, B.C.; Christensen, R.P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1956-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52551289"> <span id="translatedtitle">Iron oxide coatings on <span class="hlt">sand</span> grains from the Atlantic coastal plain: High-resolution transmission electron microscopy characterization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Nanoscale characterization of so-called iron oxide coatings on aquifer <span class="hlt">sands</span> is vital for understanding the fate and transport of naturally occurring and anthropogenic chemical species. These coatings, which typically have a strong reddish color, are commonly assumed to consist primarily of iron oxides and oxyhydroxides. This work shows that the yellowish <span class="hlt">red</span> to strong brown coatings on sediments from an</p> <div class="credits"> <p class="dwt_author">R. L. Penn; C. Zhu; H. Xu; D. R. Veblen</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60322170"> <span id="translatedtitle">Appalachian region oilfield reservoir investigations: Venango group, First, Lytle, and Second <span class="hlt">sands</span>, Walnut Bend pool, Cornplanter Township, Venango County, Pa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Bureau of Mines is investigating the susceptibility of selected pressure depleted Appalachian region oil reservoirs to more intensive recovery methods. The Bureau obtained oil-reservoir samples of the Venango First, Lytle (<span class="hlt">Red</span> Valley), and Venango Second <span class="hlt">sands</span> by rotary air coring a well in the Walnut Bend pool, Cornplanter Township, Venango County, Pa. Core analysis, well logs, geology, history and</p> <div class="credits"> <p class="dwt_author">C. E. Jr. Whieldon; W. K. Jr. Overbey</p> <p class="dwt_publisher"></p> <p class="publishDate">1966-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a style="font-weight: bold;">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014CSR....78...39A"> <span id="translatedtitle">An evaluation of the Rouse theory for <span class="hlt">sand</span> transport in the Oka estuary, Spain</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Rouse profile has been traditionally used to represent the vertical distribution of suspended <span class="hlt">sand</span> in a marine benthic boundary layer. Yet it is one of the biggest unknowns in estuarine morphodynamics, largely due to uncertainties of the ratio of the sediment fall velocity to <span class="hlt">bed</span> friction on which the Rouse exponent (R=ws/?ku*) is based. A field campaign was carried out at three different locations in the Oka estuary, northern Spain, in order to examine these uncertainties. Each location differed in grain size and flow condition thus offering a wide range of settings. The first survey was inside the estuary (wave sheltered, flood tide dominated and relatively broad estuary section), the second was at the distal ebb delta (ebb tide dominated and narrow estuary section), and the third was over the wave exposed proximal ebb delta (wave/flood tidal current combined flows and open sea). The aim of this study is to evaluate the applicability of the Rouse (1937) theory for the distribution of <span class="hlt">sand</span> in suspension throughout a turbulent benthic boundary layer. A modified version of a Helley-Smith sampler was used to trap <span class="hlt">sand</span> and measure the vertical distribution of <span class="hlt">sand</span> in the water column. As well, a 1200 ADCP was used to measure flow velocity and backscatter together with an ADV (turbulence). The <span class="hlt">sand</span> traps were found to have a sampling efficiency of 44%. The grain size at all stations was finer near the surface and coarser near the <span class="hlt">bed</span>. The <span class="hlt">sand</span> transport inside the estuary (Station 1) is inwards dominant. By contrast, the <span class="hlt">sand</span> concentration during the ebb tide was ten times higher than during the flood tide at Station 2 and even higher at Station 3, which suggests that the <span class="hlt">sand</span> transport over the ebb delta is seawards. The average Rouse parameters for Stations 1, 2, and 3 are 0.48±0.035, 0.78±0.23, and 0.46±0.06 respectively, which correspond to a coefficient of proportionality of the movability number, (?) of 4 (Van Rijn, 1993). These differ from previous findings of Villatoro et al. (2010) and Amos et al. (2010b).</p> <div class="credits"> <p class="dwt_author">Al-Ragum, A.; Monge-Ganuzas, M.; Amos, C. L.; Cearreta, A.; Townend, I.; Manca, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMEP23D0859S"> <span id="translatedtitle">Numerical simulation of turbulence and sediment transport of medium <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Eleven numerical simulations, ranging from no transport to bedload to vigorous suspension transport, are presented of a combined large eddy simulation (LES) and distinct element model (DEM) of an initially flat <span class="hlt">bed</span> of medium <span class="hlt">sand</span>. The fluid and particles are fully coupled in momentum. The friction coefficient, defined here as the squared ratio of the friction velocity to the depth-averaged velocity, is in good agreement with well-known rough <span class="hlt">bed</span> relations at no transport and increases with the intensity of bedload transport. The friction coefficient nearly doubles in value at the onset of sediment suspension owing to a rapid increase of the depth over which particles and fluid exchange momentum. The friction coefficient decreases with increasing suspension intensity because of increasingly stable stratification. Fluid Reynolds stress and time-averaged velocity profiles in the bedload regime agree well with previous experiments and simulations. Also consistent with previous studies of suspended sediment, there is an increase in slope of the lower portion of the velocity profile that has been modeled in the past using stably stratified eddy viscosity closures or an adjusted von Karman constant. Stokes numbers in the simulations, using an estimated lagrangian integral time scale, are less than unity. As such, particles faithfully follow the fluid, except for particle settling and grain-grain interactions near the <span class="hlt">bed</span>. Fluid-particle velocity correlation coefficients approach one in portions of the flow where volumetric sediment concentrations are below about ten percent. Bedload entrainment is critically connected to vertical velocity fluctuations. When a fluid packet approaches the <span class="hlt">bed</span> from the interior of the flow (i.e. a sweep), fluid is forced into the <span class="hlt">bed</span>, and at the edges of the sweep, fluid is forced out of the <span class="hlt">bed</span>. Much of the particle entrainment occurs at these sweep edges. Fluid velocity statistics following the particles reveal that moving bedload particles are preferentially concentrated in zones of upward fluid velocity. This may explain previous observations noting a rapid vertical rise at the beginning of saltation trajectories. The simulations described here have no lift forces. Because of the short particle time scales relative to that of the turbulent structures, high transport stage bedload entrainment zones involve mutual interaction between turbulence structures and <span class="hlt">bed</span> deformation. These deformation structures appear as depressed areas of the <span class="hlt">bed</span> at the center of the sweep and raised areas of entraining particles at the edges of the sweep penetration. Suspended sediment entrainment structures are similar to these bedload entrainment structures but have much larger scales. Preferential concentration of suspended grains in zones of upward moving fluid dampens turbulence intensities and momentum transport. Much of the suspended transport takes place within this highly concentrated near-<span class="hlt">bed</span> zone of damped turbulence. Particle-fluid correlation coefficients are relatively low in the lower portion of this highly concentrated suspended sediment zone, owing to particle-particle interactions. As such, Rouse-like profiles utilizing eddy viscosity closures, adjusted according to flux Richardson numbers, do not adequately describe the physics of this zone.</p> <div class="credits"> <p class="dwt_author">Schmeeckle, M. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006GeoRL..3323614K"> <span id="translatedtitle">Geological and oceanographic perspectives on event <span class="hlt">bed</span> formation during Hurricane Katrina</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Storm deposits in ancient shelf sediments typically form thick sequences of interbedded <span class="hlt">sand</span> and mud deposited during shoreline regression, whereas modern shelf sediments are generally thin veneers deposited during shoreline transgression. In this paper we present a preliminary comparison between ancient and modern storm <span class="hlt">beds</span> deposited in these disparate contexts. Hurricane Katrina deposited a storm <span class="hlt">bed</span> on the Louisiana shelf with a maximum observed thickness of 0.58 m, which thinned to approximately 0.1 m at 200 km west of landfall. This thickness is similar to event <span class="hlt">beds</span> observed in both ancient and modern sediments. Using data for tropical cyclone landfalls in the Gulf of Mexico, we estimate the return time for a storm of this size to be 40-50 years in this region. This estimated frequency for deposition of storm <span class="hlt">beds</span> is useful in evaluating ancient storm sequences that were deposited during similar climatic conditions.</p> <div class="credits"> <p class="dwt_author">Keen, T. R.; Furukawa, Y.; Bentley, S. J.; Slingerland, R. L.; Teague, W. J.; Dykes, J. D.; Rowley, C. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/11280986"> <span id="translatedtitle">Evaluation of waste pyrolysis characteristics in a pressurized fluidized <span class="hlt">bed</span> reactor.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">To obtain the distribution of fuel components to gas, tar and char in a pressurized fluidized <span class="hlt">bed</span> waste pyrolyzer, experiments were conducted with a laboratory scale fluidized <span class="hlt">bed</span> reactor. Waste samples were fed batchwise from the top of the reactor into the fluidized <span class="hlt">bed</span> of silica <span class="hlt">sand</span> and pyrolyzed by nitrogen/nitrogen-O2 gas and the effects of pressure, particle size, heating rate and oxygen addition were investigated. In the case of rubber, the char yield tended to increase a little and the tar yield decrease over the pressure of 304-709 kPa. In comparison with the thermogravimetry data it was clearly demonstrated that the char yield from fluidized <span class="hlt">bed</span> pyrolysis is much lower. A small amount of oxygen addition decreased both tar and char yields but its further increase did not affect them very much. PMID:11280986</p> <div class="credits"> <p class="dwt_author">Ono, A; Kurita, M; Nagashima, T; Horio, M</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18693006"> <span id="translatedtitle">Tar removal during the fluidized <span class="hlt">bed</span> gasification of plastic waste.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A recycled polyethylene was fed in a pilot plant bubbling fluidized <span class="hlt">bed</span> gasifier, having an internal diameter of 0.381 m and a maximum feeding capacity of 90 kg/h. The experimental runs were carried out under various operating conditions: the <span class="hlt">bed</span> temperature was kept at about 850 degrees C, the equivalence ratio varied between 0.2 and 0.35, the amount of <span class="hlt">bed</span> material was between 131 and 215 kg, the fluidizing velocity was between 0.5 and 0.7 m/s, quartz <span class="hlt">sand</span> and olivine were used as <span class="hlt">bed</span> material, and air and steam were used as fluidizing reactants. The results confirm that the tar removal treatments applied inside the gasifier (primary methods) can eliminate or strongly reduce the need for a further downstream cleanup of the syngas. In particular, the utilization of a natural olivine as an in situ tar reduction agent remarkably improves the quality of the product gas, in terms of both high hydrogen volumetric fraction and larger syngas yield. PMID:18693006</p> <div class="credits"> <p class="dwt_author">Arena, Umberto; Zaccariello, Lucio; Mastellone, Maria Laura</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.2804M"> <span id="translatedtitle">Central Asian <span class="hlt">sand</span> seas climate change as inferred from OSL dating</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Luminescence dating techniques have become more accessible, widespread, more accurate and support studies of climate change. Optically stimulated luminescence (OSL) is used to determine the time elapsed since quartz grains were last exposed to sunlight, before they were buried and the dune stabilized. Many <span class="hlt">sand</span> seas have been dated extensively by luminescence, e.g., the Kalahari, Namib the Australian linear dunes and the northwestern Negev dune field, Israel. However, no ages were published so far from the central Asian <span class="hlt">sand</span> seas. The lack of dune stratigraphy and numerical ages precluded any reliable assessment of the paleoclimatic significance of dunes in central Asia. Central Asian <span class="hlt">Sand</span> seas (ergs) have accumulated in the Turan basin, north-west of the Hindu Kush range, and span from south Turkmenistan to the Syr-Darya River in Kazakhstan. These ergs are dissected by the Amu-Darya River; to its north lies the Kyzylkum (<span class="hlt">red</span> <span class="hlt">sands</span>) and to its south lies the Karakum (black <span class="hlt">sands</span>). Combined, they form one of the largest <span class="hlt">sand</span> seas in the world. This area is understudied, and little information has been published regarding the <span class="hlt">sands</span> stabilization processes and deposition ages. In this study, OSL ages for the Karakum and Kyzylkum <span class="hlt">sands</span> are presented and analysis of the implications of these results is provided. Optical dates obtained in this study are used to study the effects climatic changes had on the mobility and stability of the central Asian <span class="hlt">sand</span> seas. Optically stimulated luminescence ages derived from the upper meter of the interdune of 14 exposed sections from both ergs, indicate extensive <span class="hlt">sand</span> and dune stabilization during the mid-Holocene. This stabilization is understood to reflect a transition to a warmer, wetter, and less windy climate that generally persisted until today. The OSL ages, coupled with a compilation of regional paleoclimatic data, corroborate and reinforce the previously proposed Mid-Holocene Liavliakan phase, known to reflect a warmer, wetter, and less windy climate that persists until today and resulted in dune stabilization around the Mid-Holocene. This study, solidifies our results regarding the Kyzylkum and Karakum <span class="hlt">sand</span> seas dynamics, ages, and emphasizes the importance of regional climatic control on aeolian activity.</p> <div class="credits"> <p class="dwt_author">Maman, Shimrit; Tsoar, Haim; Blumberg, Dan; Porat, Naomi</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/864384"> <span id="translatedtitle"><span class="hlt">Bed</span> drain cover assembly for a fluidized <span class="hlt">bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A loose fitting movable cover plate (36), suitable for the severe service encountered in a fluidized <span class="hlt">bed</span> combustor (10), restricts the flow of solids into the combustor drain lines (30) during shutdown of the <span class="hlt">bed</span>. This cover makes it possible to empty spent solids from the <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Comparato, Joseph R. (Bloomfield, CT); Jacobs, Martin (Hartford, CT)</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41326065"> <span id="translatedtitle">Paleobiology of the <span class="hlt">Sand</span> Beneath the Valders Diamicton at Valders, Wisconsin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty <span class="hlt">sand</span> and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,20014C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the <span class="hlt">red</span>-brown diamicton of</p> <div class="credits"> <p class="dwt_author">Louis J. Maher; Norton G. Miller; Richard G. Baker; B. Brandon Curry; David M. Mickelson</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMEP53B1021R"> <span id="translatedtitle">Field Observation and Numerical Modeling of <span class="hlt">Bed</span>-Material Transport Dynamics in the Lower Mississippi River</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Understanding specific pathways for <span class="hlt">sand</span> transport through the lower reaches of large rivers like the Mississippi is a key to addressing (1) significant source-to-sink geologic problems for sediment and particulate organic carbon and (2) environmental restoration efforts in deltas under threat from climate change. Five field studies were performed in the Mississippi River 75-100 km upstream of the Gulf of Mexico outlet in 2010 and 2011 at discharges ranging from 18,500 to 32,000 m3 s-1 to examine <span class="hlt">sand</span> transport phenomena in the river channel. These studies utilized multibeam sonar bathymetric surveys, acoustic Doppler current profiler measurements of current velocity and acoustic backscatter, point-integrated isokinetic suspended sediment sampling, and channel-<span class="hlt">bed</span> grab sampling to examine fluid flow and suspended/bedload sediment transport. Substantial interaction was observed between flow conditions in the river (boundary shear stress, turbulence intensity), channel-<span class="hlt">bed</span> morphology (size and extent of sandy bedforms), and <span class="hlt">bed</span>-material <span class="hlt">sand</span> transport (quantity, transport mode, and spatial distribution). A lateral shift was observed in the region of maximum dune size and water column turbulence intensity from deep to shallow areas of lateral <span class="hlt">sand</span> bars as water discharge increased, and is associated with the expansion of the bar top area experiencing critical shear stress conditions. <span class="hlt">Bed</span> material was transported both in traction and in suspension at these water discharges, with the highest suspended mass flux rates associated with the part of the channel cross-section where the largest dunes were present, as a result of a relationship between <span class="hlt">bed</span> shear stress, dune size, and turbulence intensity. We posit that the downriver flux of <span class="hlt">sand</span> grains alternates between these two modes over relatively short spatial (up to a few km) and temporal scales. These results complicate the task of using cross-sectional flux measurements taken in lower reaches of large river channels to infer <span class="hlt">bed</span>-material discharge to the ocean because the transport trajectories and velocities of individual grains can vary appreciably. This suggests that 3D numerical simulations, calibrated and validated by comprehensive field measurements, will provide the path forward in understanding <span class="hlt">bed</span> material fluxes in these systems. These model simulations, utilizing Delft3D and Flow3D and these observational data, are under development to investigate the relationship between flow conditions and sediment transport at finer spatial scales.</p> <div class="credits"> <p class="dwt_author">Ramirez, M. T.; Allison, M. A.; Meselhe, E. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMOS53B1696K"> <span id="translatedtitle">Large-eddy simulation of coupled turbulence, free surface, and <span class="hlt">sand</span> wave evolution in an open channel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We develop and validate a coupled 3D numerical model for carrying out three-phase large-eddy simulations of turbulence, free-surface, and <span class="hlt">sand</span> waves-<span class="hlt">bed</span> morphodynamics under live <span class="hlt">bed</span> conditions. We employ the Fluid-Structure Interaction Curvilinear Immersed Boundary (FSI-CURVIB) method of Khosronejad et al. (Adv. in Water Res., 2011). The LES is implemented in the context of the CURVIB method using wall modeling (Kang and Sotiropoulos, Adv. in Water Res., 2011). Free-surface motion is simulated by coupling the CURVIB method with a two-phase level set approach as in Kang and Sotiropoulos (Adv. in Water Res., 2012). The mobile channel <span class="hlt">bed</span> is discretized with an unstructured triangular grid and treated as the sharp-interface immersed boundary embedded in a background curvilinear mesh. Transport of <span class="hlt">bed</span> load and suspended load sediments are combined in the non-equilibrium form of the Exner-Poyla for the <span class="hlt">bed</span> surface elevation, which evolves due to the spatio-temporally varying <span class="hlt">bed</span> shear stress field induced by the turbulent flow. Simulations are carried out for the rectangular flume experiments of Venditti et al. (2005). It is shown that the model can accurately capture <span class="hlt">sand</span>-wave initiation, growth, and migration processes observed in the experiment. The simulated <span class="hlt">bed</span>-forms are found to have amplitude and wave length scales of ~5 cm and ~30 cm, respectively. The effects of free-surface on <span class="hlt">bed</span>-form dynamics is also quantified by comparing the three-phase simulation results with two-phase simulations using a fixed rigid-lid as the water surface.</p> <div class="credits"> <p class="dwt_author">Khosronejad, A.; Sotiropoulos, F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/23415767"> <span id="translatedtitle">Erratum to “A novel interconnected fluidised <span class="hlt">bed</span> for the combined flash pyrolysis of biomass and combustion of char”</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A novel system of two adjacent fluidised <span class="hlt">beds</span> operating in different gas atmospheres and exchanging solids was developed for the combined flash pyrolysis of biomass and combustion of the produced char. Fluidised <span class="hlt">sand</span> particles (200 ?m < dp < 400 ?m) are transported from the pyrolysis reactor to the combustor through an orifice and recycled by a standpipe, riser and</p> <div class="credits"> <p class="dwt_author">Arthur M. C. Janse; P. Maarten Biesheuvel; Wolter Prins; Wim P. M. van Swaaij</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/36016973"> <span id="translatedtitle">Conidial quality of the biocontrol agent Coniothyrium minitans produced by solid-state cultivation in a packed-<span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Conidial germination and novel <span class="hlt">sand</span>- and soil-based sclerotial parasitism assays were used to test the quality of conidial inoculum of the biocontrol agent Coniothyrium minitans IVT1 produced in different packed <span class="hlt">bed</span> reactor runs. The fermenter airflow rate was either kept constant, resulting in a transient increase in temperature at the top of the fermenter above 30°C (above the maximum for</p> <div class="credits"> <p class="dwt_author">E. E. Jones; F. J. Weber; J. Oostra; A. Rinzema; A. Mead; J. M. Whipps</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=35684"> <span id="translatedtitle">EXPERIMENTAL AND ENGINEERING SUPPORT FOR THE CAFB (CHEMICALLY ACTIVE FLUID-<span class="hlt">BED</span>) DEMONSTRATION: RESIDUE DISPOSAL/UTILIZATION</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">The report gives results of an investigation of the disposal and utilization of spent sulfur sorbent from the Chemically Active Fluid-<span class="hlt">bed</span> (CAFB) process. Lignite ash with a minimum of 10% CaO can be used as a replacement for <span class="hlt">sand</span> or medium aggregate or as a partial replacement fo...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AdWR...31.1242R"> <span id="translatedtitle">Solute dilution under imbibition and drainage conditions in a heterogeneous structure: Modeling of a <span class="hlt">sand</span> tank experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This study aims at modeling the transport of a conservative tracer in two dimensions, as experimentally observed in a strongly heterogeneous medium under conditions of variable water saturation during drainage and imbibition. Solute transport experiments were conducted in a <span class="hlt">sand</span> tank containing an artificial packing of three quartz <span class="hlt">sands</span> of different particle sizes. The packing was characterized by the presence of numerous homogeneous layers (0.5 × 5 × 5 cm) inclined at 45° and randomly distributed in a tank. Six different stationary flow conditions were sequentially established during imbibition and drainage. When a stationary flow regime was reached, several solute pulses were applied at different positions at the upper surface of the <span class="hlt">sand</span> structure. The transport regime was studied by monitoring the tracer plumes injected as point-like pulses at the surface, as they travelled through the <span class="hlt">sand</span> <span class="hlt">bedding</span>. A textural map was generated from a digital image of the <span class="hlt">sand</span> <span class="hlt">bedding</span>. The Richards equation was solved with the experimental boundary conditions assuming homogeneity of the individual <span class="hlt">sand</span> layers. The hydraulic properties of the three quartz <span class="hlt">sands</span> were deduced from multistep-outflow column experiments [Ursino N, Gimmi T. Combined effect of heterogeneity, anisotropy and saturation on steady state flow and transport: structure recognition and numerical simulation. Water Resour Res 2004;40. doi:10.1029/2003WR002180]. The convection-dispersion equation was solved on the resulting flow fields for solute pulses of given solute mass applied onto the top boundary at the same positions as in the experiment. The simulated and observed solute concentration distributions were then compared. In agreement with the experimental observations, the simulations reproduced the existence of preferential pathways in those stationary flow fields at low saturation degrees. The values of the vertical and horizontal macroscopic dispersivities obtained from the simulations are smaller than experimentally observed, especially at low flow rates. The simulated solute concentration distributions show a realistic degree of solute dilution quantified as reactor ratio.</p> <div class="credits"> <p class="dwt_author">Rossi, M.; Ippisch, O.; Flühler, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21597054"> <span id="translatedtitle">Litter ammonia generation: moisture content and organic versus inorganic <span class="hlt">bedding</span> materials.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Negative impacts on the environment, bird well-being, and farm worker health indicate the need for abatement strategies for poultry litter NH(3) generation. Type of <span class="hlt">bedding</span> affects many parameters related to poultry production including NH(3) losses. In a randomized complete block design, 3 trials compared the cumulative NH(3) volatilization for laboratory-prepared litter (4 <span class="hlt">bedding</span> types mixed with excreta) and commercial litter (sampled from a broiler house during the second flock on reused pine wood chips). Litters were assessed at the original moisture content and 2 higher moisture contents. Broiler excrement was mixed with pine wood shavings, rice hulls, <span class="hlt">sand</span>, and vermiculite to create litter samples. Volumetrically uniform litter samples were placed in chambers receiving humidified air where the exhaust passed through H(3)BO(3) solution, trapping litter-emitted NH(3). At the original moisture content, <span class="hlt">sand</span> and vermiculite litters generated the most NH(3) (5.3 and 9.1 mg of N, respectively) whereas wood shavings, commercial, and rice hull litters emitted the least NH(3) (0.9-2.6 mg of N). For reducing NH(3) emissions, the results support recommendations for using wood shavings and rice hulls, already popular <span class="hlt">bedding</span> choices in the United States and worldwide. In this research, the organic <span class="hlt">bedding</span> materials generated the least NH(3) at the original moisture content when compared with the inorganic materials. For each <span class="hlt">bedding</span> type, incremental increases in litter moisture content increased NH(3) volatilization. However, the effects of <span class="hlt">bedding</span> material on NH(3) volatilization at the increased moisture levels were not clearly differentiated across the treatments. Vermiculite generated the most NH(3) (26.3 mg of N) at the highest moisture content. Vermiculite was a novel <span class="hlt">bedding</span> choice that has a high water absorption capacity, but because of high NH(3) generation, it is not recommended for further study as broiler <span class="hlt">bedding</span> material. Controlling unnecessary moisture inputs to broiler litter is a key to controlling NH(3) emissions. PMID:21597054</p> <div class="credits"> <p class="dwt_author">Miles, D M; Rowe, D E; Cathcart, T C</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/902748"> <span id="translatedtitle">Coal <span class="hlt">Bed</span> Methane Primer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">During the second half of the 1990's Coal <span class="hlt">Bed</span> 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 <span class="hlt">Bed</span> 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 <span class="hlt">bed</span> 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 stakeholders to present a consistent and complete synopsis of the key issues involved with CBM. In light of the numerous CBM NEPA documents under development this Primer could be used to support various public scoping meetings and required public hearings throughout the Western States in the coming years.</p> <div class="credits"> <p class="dwt_author">Dan Arthur; Bruce Langhus; Jon Seekins</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-25</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20010096253&hterms=quadriceps+angle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dquadriceps%2Bangle"> <span id="translatedtitle"><span class="hlt">Bed</span> Rest Muscular Atrophy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A major debilitating response from prolonged <span class="hlt">bed</span> 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 <span class="hlt">bed</span> by his mother in 1932: after 50 years in <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Greenleaf, John E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/863485"> <span id="translatedtitle">Fast fluidized <span class="hlt">bed</span> steam generator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A steam generator in which a high-velocity, combustion-supporting gas is passed through a <span class="hlt">bed</span> of particulate material to provide a fluidized <span class="hlt">bed</span> 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 <span class="hlt">bed</span> to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized <span class="hlt">bed</span>. 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 <span class="hlt">bed</span> and the upper portion by the entrained-phase fluidized <span class="hlt">bed</span>.</p> <div class="credits"> <p class="dwt_author">Bryers, Richard W. (Flemington, NJ); Taylor, Thomas E. (Bergenfield, NJ)</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/5320685"> <span id="translatedtitle">Biparticle fluidized <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Scott, C.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-12-14</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930017765&hterms=pinky&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dpinky"> <span id="translatedtitle">Particle <span class="hlt">bed</span> reactor modeling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The topics are presented in viewgraph form and include the following: particle <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Sapyta, Joe; Reid, Hank; Walton, Lew</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a 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<div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/869067"> <span id="translatedtitle">Biparticle fluidized <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Scott, Charles D. (Oak Ridge, TN)</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/869848"> <span id="translatedtitle">Biparticle fluidized <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Scott, Charles D. (Oak Ridge, TN); Marasco, Joseph A. (Kingston, TN)</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/870316"> <span id="translatedtitle">Biparticle fluidized <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Scott, Charles D. (Oak Ridge, TN); Marasco, Joseph A. (Kingston, TN)</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/46299"> <span id="translatedtitle">Biparticle fluidized <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Scott, C.D.; Marasco, J.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-04-25</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41329659"> <span id="translatedtitle">Invasive plants on disturbed Korean <span class="hlt">sand</span> dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">sand</span> dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of <span class="hlt">sand</span> dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused</p> <div class="credits"> <p class="dwt_author">Kee Dae Kim</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/mQHs38Vjj1_85"> <span id="translatedtitle">Liquefaction in Subsurface Layer of <span class="hlt">Sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">Ground shaking triggered liquefaction in a subsurface layer of <span class="hlt">sand</span>, producing differential lateral and vertical movement in a overlying carapace of unliquified <span class="hlt">sand</span> and silt, which moved from right to left toward the Pajaro River. This mode of ground failure, termed "lateral spreading," is a p...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-26</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=plastic+AND+water+AND+bottles&id=EJ635682"> <span id="translatedtitle">Explorations with the <span class="hlt">Sand</span> and Water Table.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Presents <span class="hlt">sand</span> and water activities for young children as examples of sensory explorations, science activities, and comforting play. Includes information on health and safety precautions, adaptations for children with physical disabilities, the use of other materials, and <span class="hlt">sand</span> and water toys made from one-liter plastic bottles. (KB)</p> <div class="credits"> <p class="dwt_author">Texas Child Care, 2001</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=45229"> <span id="translatedtitle">NEW DEVELOPMENTS IN SLOW <span class="hlt">SAND</span> FILTRATION</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">Recent regulations promulgated by the U.S. Environmental Protection Agency (EPA), including the Surface Water Treatment Rule, have helped to renew the interest in the use of slow <span class="hlt">sand</span> filtration (SSF) for treating surface waters for small communities. low <span class="hlt">sand</span> filtration is not a...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=48637"> <span id="translatedtitle">DRINKING WATER TREATMENT USING SLOW <span class="hlt">SAND</span> FILTRATION</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">Recent re-interest in slow <span class="hlt">sand</span> filtration was brought about by the needs for small communities to install treatment technologies that are effective, less costly, and easier to operate and maintain than the more sophisticated rapid <span class="hlt">sand</span> filters. These simpler technologies for sma...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/378056"> <span id="translatedtitle"><span class="hlt">Sand</span> reinforced with shredded waste tires</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce <span class="hlt">sand</span>. Direct shear tests were conducted on mixtures of dry <span class="hlt">sand</span> and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, <span class="hlt">sand</span> matrix unit weight, shred content, shred length, and shred orientation. From results of the tests, three significant factors affecting shear strength were identified: normal stress, shred content, and <span class="hlt">sand</span> matrix unit weight. A model for estimating the strength of reinforced soils was also evaluated to determine its applicability to mixtures of <span class="hlt">sand</span> and tire shreds. When the model is calibrated using results from one shred content, it may be useful for estimating the friction angle for other shred contents. In all cases, adding shredded tires increased the shear strength of <span class="hlt">sand</span>, with an apparent friction angle ({phi}{prime}) as large as 67{degree} being obtained. Shred content and <span class="hlt">sand</span> matrix unit weight were the most significant characteristics of the mixes influencing shear strength. Increasing either of these variables resulted in an increase in {phi}{prime}. Tests were also conducted on specimens consisting of only shredded tires (no <span class="hlt">sand</span>), and the friction angle obtained was 30{degree}.</p> <div class="credits"> <p class="dwt_author">Foose, G.J.; Benson, C.H.; Bosscher, P.J. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering] [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/3021954"> <span id="translatedtitle">Elastic properties of unconsolidated porous <span class="hlt">sand</span> reservoirs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The effect of compressive stress and pore fluid properties on elastic properties of unconsolidated <span class="hlt">sand</span> reservoirs was determined by laboratory velocity and pore volume measurements on two specimens. These consisted of a naturally occurring very fine grained <span class="hlt">sand</span> and glass beads, each with a porosity of approximately 38 percent. Compressional- and shear-wave velocities and pore compressibility were measured in the</p> <div class="credits"> <p class="dwt_author">S. N. Domenico</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60301001"> <span id="translatedtitle">Western gas <span class="hlt">sands</span>: Technology status report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Western gas <span class="hlt">sands</span> research is conducted by the US Department of Energy's (DOE's) Morgantown Energy Technology Center to encourage the development of very low permeability, lenticular gas <span class="hlt">sands</span> in the western US. This research is an integral part of DOE's Unconventional Gas Recovery Program, which is a multidisciplinary effort to develop the technology for producing natural gas from resources that</p> <div class="credits"> <p class="dwt_author">K. H. Frohne; C. A. Komar</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19810000102&hterms=fluidized+bed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfluidized%2Bbed"> <span id="translatedtitle">Capacitively-Heated Fluidized <span class="hlt">Bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Fluidized-<span class="hlt">bed</span> chamber in which particles in <span class="hlt">bed</span> are capacitively heated produces high yields of polycrystalline silicon for semiconductor devices. Deposition of unrecoverable silicon on chamber wall is reduced, and amount of recoverable silicon depositing on seed particles in <span class="hlt">bed</span> is increased. Particles also have a size and density suitable for direct handling without consolidation, unlike silicon dust produced in heated-wall chambers.</p> <div class="credits"> <p class="dwt_author">Mchale, E. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/863850"> <span id="translatedtitle">Fluidized <span class="hlt">bed</span> boiler feed system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A fluidized <span class="hlt">bed</span> 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 <span class="hlt">bed</span> while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized <span class="hlt">bed</span> to promote char burnout and to avoid elutriation and carryover.</p> <div class="credits"> <p class="dwt_author">Jones, Brian C. (Windsor, CT)</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70027337"> <span id="translatedtitle">Debris-<span class="hlt">bed</span> friction of hard-<span class="hlt">bedded</span> glaciers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">[1] Field measurements of debris-<span class="hlt">bed</span> friction on a smooth rock tablet at the <span class="hlt">bed</span> of Engabreen, a hard-<span class="hlt">bedded</span>, 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 <span class="hlt">bed</span> by <span class="hlt">bed</span>-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 <span class="hlt">bed</span>-normal drag force on a sphere in contact with a flat <span class="hlt">bed</span> using n = 1 show that this force can reach values several hundred times that on a sphere isolated from the <span class="hlt">bed</span>, thus drastically increasing frictional resistance. Various estimates of basal friction are obtained from this model. For example, the shear traction at the <span class="hlt">bed</span> 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-<span class="hlt">bed</span> friction can therefore be a major component of sliding resistance, contradicting the common assumption that debris-<span class="hlt">bed</span> friction is negligible. Copyright 2005 by the American Geophysical Union.</p> <div class="credits"> <p class="dwt_author">Cohen, D.; Iverson, N.R.; Hooyer, T.S.; Fischer, U.H.; Jackson, M.; Moore, P.L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA04906&hterms=mound+laboratories&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmound%2Blaboratories"> <span id="translatedtitle">Hematite Outlier and <span class="hlt">Sand</span> Dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> [figure removed for brevity, see original site] <p/>Released 4 December 2003<p/>This image shows a crater just south of the edge of the famous hematite-bearing surface, which is visible in the context image as a smooth area to the north. The crater has two features of immediate note. The first is a layered mound in the north part of the crater floor. This mound contains hematite, and it is an outlying remnant of the greater deposits to the north that have otherwise completely disappeared in this crater. The second feature is a dune field in the center of the crater floor, with dark dunes indicating winds from the northwest. The dunes grade into a dark <span class="hlt">sand</span> sheet with no coherent structure, indicating that the <span class="hlt">sand</span> layer thins out to the south and east.<p/>Image information: VIS instrument. Latitude -4.4, Longitude 357.3 East (2.7 West). 19 meter/pixel resolution.<p/>Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.<p/>NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013GGG....14.3720B"> <span id="translatedtitle">Iron-rich nanoparticles formed by aeolian abrasion of desert dune <span class="hlt">sand</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Iron-rich nanoparticles in aeolian mineral dust are of considerable importance to biogeochemical cycles. A major determinant of the chemical characteristics of nanoparticles is the parent sediment they are sourced from. The abrasion of dune <span class="hlt">sand</span> has previously been shown to produce coarse dust (>1 ?m) during the occurrence of aeolian saltation. In this study, Australian <span class="hlt">red</span> dune <span class="hlt">sands</span> were laboratory abraded and emission of particles 18-414 nm was observed throughout the experiment duration (˜1 h). The mean size of particles was 130 nm at the start of the test, but this gradually decreased to 110 nm at the end. The number concentration of particles approximately trebled over the course of the experiment with results suggesting that collisions between mobile <span class="hlt">sand</span> grains led to the production of new nanosized particles over time. Chemical analysis revealed that these nanoparticles were highly abundant in iron, with some aluminium present. This chemical composition suggests that nanoparticles are produced from the clay coatings surrounding the parent <span class="hlt">sand</span> grains. The study shows that abrasion from saltation occurring in Australian dune <span class="hlt">sands</span> can release iron-rich nanoparticles, making them available for downwind transport during blowing dust events.</p> <div class="credits"> <p class="dwt_author">Baddock, Matthew; Boskovic, Lucija; Strong, Craig; McTainsh, Grant; Bullard, Joanna; Agranovski, Igor; Cropp, Roger</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3287326"> <span id="translatedtitle">Ecological release in White <span class="hlt">Sands</span> lizards</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Ecological opportunity is any change that allows populations to escape selection from competition and predation. After encountering ecological opportunity, populations may experience ecological release: enlarged population size, broadened resource use, and/or increased morphological variation. We identified ecological opportunity and tested for ecological release in three lizard colonists of White <span class="hlt">Sands</span>, New Mexico (Sceloporus undulatus, Holbrookia maculata, and Aspidoscelis inornata). First, we provide evidence for ecological opportunity by demonstrating reduced species richness and abundance of potential competitors and predators at White <span class="hlt">Sands</span> relative to nearby dark soils habitats. Second, we characterize ecological release at White <span class="hlt">Sands</span> by demonstrating density compensation in the three White <span class="hlt">Sands</span> lizard species and expanded resource use in White <span class="hlt">Sands</span> S. undulatus. Contrary to predictions from ecological release models, we observed directional trait change but not increased trait variation in S. undulatus. Our results suggest that ecological opportunity and ecological release can be identified in natural populations, especially those that have recently colonized isolated ecosystems. PMID:22393523</p> <div class="credits"> <p class="dwt_author">Roches, S Des; Robertson, J M; Harmon, L J; Rosenblum, E B</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/867677"> <span id="translatedtitle">Method for packing chromatographic <span class="hlt">beds</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">Column chromatography <span class="hlt">beds</span> are packed through the application of static force. A slurry of the chromatography <span class="hlt">bed</span> 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 <span class="hlt">bed</span>. This results in an evenly packed <span class="hlt">bed</span>, with no channeling or preferential flow characteristics.</p> <div class="credits"> <p class="dwt_author">Freeman, David H. (Potomac, MD); Angeles, Rosalie M. (Germantown, MD); Keller, Suzanne (Rockville, MD)</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.seattleu.edu/uploadedFiles/University_Recreation/Content/Aquatics/Participant%20Manual.pdf"> <span id="translatedtitle">Lifeguarding American <span class="hlt">Red</span> Cross</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Lifeguarding Manual #12;American <span class="hlt">Red</span> Cross Lifeguarding Manual The following organizations provided review of the materials and/or support American <span class="hlt">Red</span> Cross Lifeguarding: #12;This manual is part of the American <span class="hlt">Red</span> Cross Lifeguarding program. By itself, it does not constitute complete and comprehensive</p> <div class="credits"> <p class="dwt_author">Carter, John</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://oaspub.epa.gov/eims/eimsapi.dispdetail?deid=96242"> <span id="translatedtitle"><span class="hlt">RED</span>-LETTER DAYS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p class="result-summary">The word "<span class="hlt">red</span>-letter" is an adjective meaning "of special significance." It's origin is from the practice of marking Christian holy days in <span class="hlt">red</span> letters on calendars. The "<span class="hlt">red</span>-letter days" to which I refer occurred while I was a graduate student of ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/wri/1998/4002/plate-1.pdf@displayLabelpdf@notePLATE#texthttp://pubs.usgs.gov/wri/1998/4002/plate-2.pdf@displayLabelpdf@notePLATE#texthttp://pubs.usgs.gov/wri/1998/4002/plate-3.pdf"> <span id="translatedtitle">Altitude of the top of the Sparta <span class="hlt">Sand</span> and Memphis <span class="hlt">Sand</span> in three areas of Arkansas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The Sparta <span class="hlt">Sand</span> and Memphis <span class="hlt">Sand</span> form the second most productive aquifer in Arkansas. The Sparta <span class="hlt">Sand</span> and Memphis <span class="hlt">Sand</span> range in thick- ness from 0 to 900 feet, consisting of fine- to medium-grained <span class="hlt">sands</span> interbedded with layers of silt, clay, shale, and minor amounts of lignite. Within the three areas of interest, the top surface of the Sparta <span class="hlt">Sand</span> and Memphis <span class="hlt">Sand</span> dips regionally east and southeast towards the axis of the Mississippi Embayment syncline and Desha Basin. Local variations in the top surface may be attributed to a combination of continued development of structural features, differential compaction, localized faulting, and erosion of the surface prior to subsequent inundation and deposition of younger sediments.</p> <div class="credits"> <p class="dwt_author">Pugh, Aaron L.; Westerfield, Paul W.; Gonthier, Gerard J.; Poynter, David T.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040192876&hterms=CYCLE+ESTROGEN&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DCYCLE%2BESTROGEN"> <span id="translatedtitle">Blood volume responses of men and women to <span class="hlt">bed</span> rest</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper reviews a series of studies that indicate that estrogens play an important role in blood volume regulation. The first study illustrates that the plasma volume (PV) of ambulatory women fluctuates during the menstrual cycle, increasing during periods of elevated estrogens. In the second study, it was shown that exogenous and endogenous elevations in blood estrogens attenuate the decrease in PV during <span class="hlt">bed</span> rest. In the third study, the hypothesis was tested that women, who naturally have a higher blood estrogen content compared with men, will have a smaller loss of PV during <span class="hlt">bed</span> rest. Ten men and ten women underwent a 13-day, 6 degrees head-down <span class="hlt">bed</span> rest. Plasma volume and <span class="hlt">red</span> cell mass (RCM) were measured before and after <span class="hlt">bed</span> rest using 125I and 51Cr labeling, respectively. Before <span class="hlt">bed</span> rest, the men and women had similar blood volume (BV) and PV (mL/kg body weight), but the women had a smaller (P < .01) RCM (22.2 +/- 0.9 versus 26.2 +/- 0.8 mL/kg, mean +/- SE). During <span class="hlt">bed</span> rest, the decrease in RCM (mL/kg) was similar in men and women. However, the decrease in BV was greater in men (8.0 +/- 0.8 mL/kg versus 5.8 +/- 0.8 mL/kg), because of a greater reduction in PV (6.3 +/- 0.6 mL/kg versus 4.1 +/- 0.6 mL/kg). Because the decline in BV has been proposed to contribute to the cardiovascular deconditioning after <span class="hlt">bed</span> rest, it is possible that women may experience less cardiac and circulatory strain on reambulation.</p> <div class="credits"> <p class="dwt_author">Fortney, S. M.; Turner, C.; Steinmann, L.; Driscoll, T.; Alfrey, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002JGRB..107.2125B"> <span id="translatedtitle">Quantifying iron oxide coatings on dune <span class="hlt">sands</span> using spectrometric measurements: An example from the Simpson-Strzelecki Desert, Australia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Red</span> soils and sediments are common in arid and semiarid areas. The <span class="hlt">red</span> color, caused by iron oxides, has been used by researchers to infer information about sediment provenance, age, and environmental history. However, the objective description and quantification of color is problematic. This paper tests a rapid technique for quantifying ``<span class="hlt">redness</span>'' in the field using visible reflectance spectrometry. The reflectance ratings obtained from the field are converted to <span class="hlt">redness</span> values and are compared with similar measurements taken under controlled conditions. The results show that the color of dune <span class="hlt">sands</span> is determined by the variation in intensity of the UV conduction band. We demonstrate that estimates of spectral <span class="hlt">redness</span> offer much greater precision in differentiating <span class="hlt">sand</span> samples by color than conventional estimates based on color charts. The relationship between increasing <span class="hlt">redness</span> and increasing concentrations of iron oxide in the sediments is strong and positive. This suggests that, in certain circumstances, simple field spectral measurements are able to provide reliable estimates of iron oxide concentrations and <span class="hlt">redness</span>, therefore negating the need for more detailed controlled laboratory measurements.</p> <div class="credits"> <p class="dwt_author">Bullard, Joanna E.; White, Kevin</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012SedG..282..188G"> <span id="translatedtitle">Sedimentary processes associated with <span class="hlt">sand</span> and boulder deposits formed by the 2011 Tohoku-oki tsunami at Sabusawa Island, Japan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper reports on the sedimentary processes of <span class="hlt">sand</span> and boulder deposition at Sabusawa Island, Japan as a result of the 2011 Tohoku-oki tsunami. Boulders were composed of tuffaceous rocks and sourced from an earthquake-triggered slope failure as well as concrete fragments of seawall. They were scattered over the ground surface and did not form boulder ridges, although there was some local imbrication. The boulders were deposited on top of a <span class="hlt">sand</span> layer indicating that the latter, possibly deposited from <span class="hlt">bed</span> load, covered the ground surface first. This <span class="hlt">sand</span> layer probably reduced friction allowing boulders to be transported more easily than might be expected across a hard ground with a high bottom friction. <span class="hlt">Sand</span> deposits showed landward thinning and fining features, while the boulders showed a landward coarsening (tuffaceous boulders) or a landward fining (concrete boulders), indicating that large clasts were not necessarily scattered randomly but rather might have a clast size gradient with distance inland. These features are explained by the local topographic setting that constrained the directions of incoming and returning tsunami flows. Some clasts at the inland extent of the boulder field were covered by an upward fining <span class="hlt">sand</span> layer. This feature suggests that the boulders were deposited prior to the suspended <span class="hlt">sands</span>, with the latter subsequently laid down before the water level dropped below the top of the boulders. Such modern investigations of the sedimentary features of various sizes of grains and clasts immediately after a tsunami provide invaluable data for the reconstruction of inundation processes.</p> <div class="credits"> <p class="dwt_author">Goto, Kazuhisa; Sugawara, Daisuke; Ikema, Satoko; Miyagi, Toyohiko</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.education.canterbury.ac.nz/documents/brochures_2013/BEd(PE).pdf"> <span id="translatedtitle"><span class="hlt">BEd(PE)/BEd</span>(PE)(Hons) College of Education</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">13 <span class="hlt">BEd(PE)/BEd</span>(PE)(Hons) College of Education Bachelor of Education (Physical Education) / Bachelor of Education (Physical Education) with Honours #12;Disclaimer All the information in this booklet was correct at the time of printing. #12;3 The Bachelor of Education (Physical Education) and Bachelor of Education</p> <div class="credits"> <p class="dwt_author">Hickman, Mark</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cfpub.epa.gov/oppref/bedbug/"> <span id="translatedtitle">EPA-Registered <span class="hlt">Bed</span> Bug Products</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://medlineplus.gov/">MedlinePLUS</a></p> <p class="result-summary">EPA-Registered <span class="hlt">Bed</span> Bug Products Resources <span class="hlt">Bed</span> Bug Main Page Top Ten <span class="hlt">Bed</span> Bugs Tips Joint Statement on <span class="hlt">Bed</span> Bug Control EPA has developed a ... help you choose an EPA-registered <span class="hlt">bed</span> bug product that meets your needs. The products listed in ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUFM.V12B1433D"> <span id="translatedtitle">Accretionary lapilli <span class="hlt">beds</span> in the Keanakako'i Ash: footprint-bearing <span class="hlt">beds</span> not 1790 in age</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Keanakako'i Ash is the product of explosive volcanic activity at Kilauea volcano between about A.D. 1500 and 1790. The explosive eruption of 1790 killed 80-800 members of a war party near the caldera and earned a place in Hawaiian history. The deposits of this eruption consist mainly of coarse pyroclastic <span class="hlt">beds</span> and finely laminated base surge strata that form dunes in proximal areas and thin with distance away from the vent. Accompanying these deposits are thin, massive, fine ash layers a few centimeters thick containing accretionary lapilli. Human footprints are preserved in two fine ash layers abundant in accretionary lapilli at many places within 10 km southwest of Halemaumau Crater. Early researchers put these layers high in the stratigraphic section and attributed them to the 1790 eruption. The rationale behind this assumption was that the footprints were left by the war party fleeing from the eruption. Erosional gullies cut through the deposit at <span class="hlt">Sand</span> Hill, about 1 km southwest of Halemaumau Crater, and expose an almost complete proximal section. McPhie and coworkers in 1990 recognized three major unconformities in the section, each relating to a hiatus in deposition. Early investigations concluded that the Keanakako'i Ash was deposited by a series of explosive events separated by breaks in time. More recent studies suggested that the formation was deposited more quickly, with unconformities produced through erosion by pyroclastic surges. We find, however, that this hypothesis is inconsistent with field observations. Accretionary lapilli <span class="hlt">beds</span> were identified in proximal sections, separated by lithic surge deposits. These <span class="hlt">beds</span> can be traced away from <span class="hlt">Sand</span> Hill and identified by unique characteristics and small-scale stratigraphic relationships. More distally, the deposit is eroded in most places, but stratigraphic correlation is possible using small depressions that protect the ash layers from erosion. Samples were taken and individual accretionary lapilli <span class="hlt">beds</span> were characterized in terms of the constituent ash particles and of the aggregates themselves. We conclude from the correlation data that the two footprint-bearing accretionary lapilli <span class="hlt">beds</span> are separated by an unconformity, and at least the lower of these <span class="hlt">beds</span> was produced by an eruption earlier than 1790, possibly decades or more. The footprint-bearing layers have important implications not only for stratigraphic correlation, but also for the understanding of activity of ancient Hawaiians in this area and how these people viewed Pele, their volcano goddess.</p> <div class="credits"> <p class="dwt_author">Durant, A.; Swanson, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/531101"> <span id="translatedtitle">Assessing environmental risk of the retired filter <span class="hlt">bed</span> area, Battelle West Jefferson</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Initial investigations conducted by the U.S. Department of Energy, Chicago Operations Office, and by Argonne National Laboratory used seismic refraction profiling, electrical resistivity depth sounding, conductivity profiling, magnetic gradiometry, and ground-penetrating radar to study environmental geophysics in the area of the Battelle West Jefferson site`s radiologically contaminated retired filter <span class="hlt">beds</span>. The investigators used a combination of nonintrusive technologies and innovative drilling techniques to assess environmental risk at the filter <span class="hlt">beds</span> and to improve understanding of the geology of the Big Darby Creek floodplain. The geophysical investigation, which showed that the preferred groundwater pathway is associated with a laterally extensive deposit of silty <span class="hlt">sand</span> to <span class="hlt">sand</span> that is less than 12 ft deep in the floodplain area, also guided the location of cone penetrometer test sites and piezometer installation. Cone penetrometer testing was useful for comparing continuous logging data with surface geophysical data in establishing correlations among unconsolidated materials.</p> <div class="credits"> <p class="dwt_author">Miller, S.F.; Thompson, M.D.; Glennon, M.A. [and others</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.icir.org/vern/cs261n-Sp12/notes/WormThreat.pdf"> <span id="translatedtitle">Code <span class="hlt">Red</span> 2 kills off Code <span class="hlt">Red</span> 1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">#12;#12;Code <span class="hlt">Red</span> 2 kills off Code <span class="hlt">Red</span> 1 Code <span class="hlt">Red</span> 2 settles into weekly pattern Nimda enters the ecosystem Code <span class="hlt">Red</span> 2 dies off as programmed CR 1 returns thanks to bad clocks #12;Code <span class="hlt">Red</span> 2 dies off as programmed Nimda hums along, slowly cleaned up With its predator gone, Code <span class="hlt">Red</span> 1 comes back, still</p> <div class="credits"> <p class="dwt_author">Paxson, Vern</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18767752"> <span id="translatedtitle">Ability of <span class="hlt">bed</span> bug-detecting canines to locate live <span class="hlt">bed</span> bugs and viable <span class="hlt">bed</span> bug eggs.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The <span class="hlt">bed</span> bug, Cimex lectularius L., like other <span class="hlt">bed</span> bug species, is difficult to visually locate because it is cryptic. Detector dogs are useful for locating <span class="hlt">bed</span> bugs because they use olfaction rather than vision. Dogs were trained to detect the <span class="hlt">bed</span> bug (as few as one adult male or female) and viable <span class="hlt">bed</span> bug eggs (five, collected 5-6 d after feeding) by using a modified food and verbal reward system. Their efficacy was tested with <span class="hlt">bed</span> bugs and viable <span class="hlt">bed</span> bug eggs placed in vented polyvinyl chloride containers. Dogs were able to discriminate <span class="hlt">bed</span> bugs from Camponotus floridanus Buckley, Blattella germanica (L.), and Reticulitermes flavipes (Kollar), with a 97.5% positive indication rate (correct indication of <span class="hlt">bed</span> bugs when present) and 0% false positives (incorrect indication of <span class="hlt">bed</span> bugs when not present). Dogs also were able to discriminate live <span class="hlt">bed</span> bugs and viable <span class="hlt">bed</span> bug eggs from dead <span class="hlt">bed</span> bugs, cast skins, and feces, with a 95% positive indication rate and a 3% false positive rate on <span class="hlt">bed</span> bug feces. In a controlled experiment in hotel rooms, dogs were 98% accurate in locating live <span class="hlt">bed</span> bugs. A pseudoscent prepared from pentane extraction of <span class="hlt">bed</span> bugs was recognized by trained dogs as <span class="hlt">bed</span> 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 <span class="hlt">bed</span> bugs and viable <span class="hlt">bed</span> bug eggs. PMID:18767752</p> <div class="credits"> <p class="dwt_author">Pfiester, Margie; Koehler, Philip G; Pereira, Roberto M</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3976808"> <span id="translatedtitle">Critical State of <span class="hlt">Sand</span> Matrix Soils</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for <span class="hlt">sand</span> and clay are both well established. Nevertheless, the development of the critical state of <span class="hlt">sand</span> matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, <span class="hlt">sand</span> matrix soils using <span class="hlt">sand</span>-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of <span class="hlt">sand</span> matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different <span class="hlt">sand</span> matrix soils were developed together with the corresponding values of critical state parameters, M, ?, and ?. The range of the value of M, ?, and ? is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river <span class="hlt">sand</span> and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417</p> <div class="credits"> <p class="dwt_author">Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.davidcwhite.org/fulltext/323.pdf"> <span id="translatedtitle">Biodegradation of chlorinated aliphatic hydrocarbon mixtures in a single-pass packed-<span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Aliphatic chlorinated compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), are major contaminants of\\u000a ground water. A single-pass packed-<span class="hlt">bed</span> bioreactor was utilized to study the biodegradation of organic waste mixtures consisting\\u000a of PCE, TCE, and other short-chain chlorinated organics. The bioreactor consisted of two 1960-mL glass columns joined in a\\u000a series. One column was packed with <span class="hlt">sand</span> containing a microbial</p> <div class="credits"> <p class="dwt_author">L. W. Lackey; T. J. Phelps; P. R. Bienkowski; D. C. White</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54878684"> <span id="translatedtitle">Perchlorate remediation using packed-<span class="hlt">bed</span> bioreactors and electricity generation in microbial fuel cells (MFCs)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Two pilot-scale fixed <span class="hlt">bed</span> bioreactors were operated in continuous mode in order to treat groundwater contaminated by perchlorate. The bioreactors were constructed and operated side-by-side at the Texas Street Well Facility in Redlands, California. Each reactor was packed with either <span class="hlt">sand</span> or plastic media. A perchlorate-reducing bacterium, Dechlorosoma sp. KJ, was used to inoculate the bioreactors. Perchlorate was successfully removed</p> <div class="credits"> <p class="dwt_author">Booki Min</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/t746u71084038445.pdf"> <span id="translatedtitle">Effects of high temperature and combustion on fluidized material attrition in a fluidized <span class="hlt">bed</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This study investigated the effects of high temperature and combustion conditions on the attrition of fluidized material in\\u000a a fluidized <span class="hlt">bed</span>. Silica <span class="hlt">sand</span> was fluidized in air at an atmospheric pressure between 873 K and 1,073 K. The operating parameters\\u000a evaluated in investigating the attrition rate of fluidized material included particle size, temperature and both combustion\\u000a and non-combustion conditions. Experimental</p> <div class="credits"> <p class="dwt_author">Chiou-Liang Lin; Ming-Yen Wey</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/343809"> <span id="translatedtitle">Carbon attrition during the circulating fluidized <span class="hlt">bed</span> combustion of a packaging-derived fuel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Cylindrical pellets of a market-available packaging-derived fuel, obtained from a mono-material collection of polyethylene terephthalate (PET) bottles, were batchwise fed to a laboratory scale circulating fluidized <span class="hlt">bed</span> (CFB) combustor. The apparatus, whose riser was 41 mm ID and 4 m high, was operated under both inert and oxidizing conditions to establish the relative importance of purely mechanical attrition and combustion-assisted attrition in generating carbon fines. Silica <span class="hlt">sand</span> particles of two size distributions were used as inert materials. For each run, carbon load and carbon particle size distribution in the riser and rates of attrited carbon fines escaping the combustor were determined as a function of time. A parallel investigation was carried out with a bubbling fluidized <span class="hlt">bed</span> (BFB) combustor to point out peculiarities of attrition in CFB combustors. After devolatilization, PET pellets generated fragile aggregates of char and <span class="hlt">sand</span>, which easily crumbled, leading to single particles, partially covered by a carbon-rich layer. The injected fixed carbon was therefore present in the <span class="hlt">bed</span> in three phases: an A-phase, made of aggregates of <span class="hlt">sand</span> and char, an S-phase, made of individual carbon-covered <span class="hlt">sand</span> particles and an F-phase, made of carbon fines, abraded by the surfaces of the A- and S-phases. The effects of the size of inert material on the different forms under which fixed carbon was present in the <span class="hlt">bed</span> and on the rate of escape of attrited carbon fines from the combustor were investigated. Features of carbon attrition in CFB and BFB combustors are discussed.</p> <div class="credits"> <p class="dwt_author">Mastellone, M.L. [Univ. Federico II of Naples, Napoli (Italy). Dept. of Chemical Engineering] [Univ. Federico II of Naples, Napoli (Italy). Dept. of Chemical Engineering; Arena, U. [National Research Council, Napoli (Italy). Inst. for Combustion Research] [National Research Council, Napoli (Italy). Inst. for Combustion Research; [Univ. of Naples, Caserta (Italy). Dept. of Environmental Sciences</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/22836441"> <span id="translatedtitle">Fluidized <span class="hlt">bed</span> nuclear fission reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">For the further development of nuclear fission reactors, the feasibility of a new concept is evaluated. It concerns a fluidized <span class="hlt">bed</span> reactor in which carbon particles with a uranium core are fluidized and cooled by a high velocity pressurized helium flow. Nuclear reaction takes place if the <span class="hlt">bed</span> is in fluidized conditions at a void fraction above 80% and it</p> <div class="credits"> <p class="dwt_author">T. H. J. J. Van Der Hagen; H. Van Dam</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20140004376&hterms=test&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dtest"> <span id="translatedtitle">LSP Composite Test <span class="hlt">Bed</span> Design</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This document provides standalone information for the Lightning Strike Protection (LSP) Composite Substrate Test <span class="hlt">Bed</span> Design. A six-sheet drawing set is reproduced for reference, as is some additional descriptive information on suitable sensors and use of the test <span class="hlt">bed</span>.</p> <div class="credits"> <p class="dwt_author">Day, Arthur C.; Griess, Kenneth H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70022744"> <span id="translatedtitle">Optical dating of tsunami-laid <span class="hlt">sand</span> from an Oregon coastal lake</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Optical ages for five samples of tsunami-laid <span class="hlt">sand</span> from an Oregon coastal lake were determined using an infrared optical-dating method on K-feldspar separates and, as a test of accuracy, compared to ages determined by AMS 14C dating of detrital plant fragments found in the same <span class="hlt">beds</span>. Two optical ages were about 20% younger than calibrated 14C ages of about 3.1 and 4.3 ka. Correction of the optical ages using measured anomalous fading rates brings them into agreement with the 14C ages. The approach used holds significant promise for improving the accuracy of infrared optical-dating methods. Luminescence data for the other three samples result in optical age limits much greater than the 14C ages. These data provide a textbook demonstration of the correlation between scatter in the luminescence intensity of individual sample aliquots and their normalization values that is expected when the samples contain <span class="hlt">sand</span> grains not adequately exposed to daylight just prior to or during deposition and burial. Thus, the data for these three samples suggest that the tsunamis eroded young and old <span class="hlt">sand</span> deposits before dropping the <span class="hlt">sand</span> in the lake. ?? 2001 Elsevier Science Ltd. All rights reserved.</p> <div class="credits"> <p class="dwt_author">Ollerhead, J.; Huntley, D.J.; Nelson, A.R.; Kelsey, H.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005ECSS...62..353K"> <span id="translatedtitle">Invasive plants on disturbed Korean <span class="hlt">sand</span> dunes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">sand</span> dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of <span class="hlt">sand</span> dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of <span class="hlt">sand</span> dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on <span class="hlt">sand</span> dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, <span class="hlt">sand</span> and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean <span class="hlt">sand</span> dune areas were found to be the introduction of native plant species from one <span class="hlt">sand</span> dune into other <span class="hlt">sand</span> dune areas, prohibition of building and the introduction of exotic soils, and conservation of surrounding <span class="hlt">sand</span> dune areas.</p> <div class="credits"> <p class="dwt_author">Kim, Kee Dae</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" 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onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_22");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/253866"> <span id="translatedtitle">Dynamic <span class="hlt">bed</span> reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A dynamic <span class="hlt">bed</span> 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.</p> <div class="credits"> <p class="dwt_author">Stormo, K.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-07-02</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3240855"> <span id="translatedtitle">Fecal indicators in <span class="hlt">sand</span>, <span class="hlt">sand</span> contact, and risk of enteric illness among beachgoers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background Beach <span class="hlt">sand</span> can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with <span class="hlt">sand</span> contact remains unclear. Methods In 2007, visitors at two recreational marine beaches were asked on the day of their visit about <span class="hlt">sand</span> contact. Ten to 12 days later, participants answered questions about health symptoms since the visit. F+ coliphage, Enterococcus, Bacteroidales, fecal Bacteroides, and Clostridium spp. in wet <span class="hlt">sand</span> were measured using culture and molecular methods. Results We analyzed 144 wet <span class="hlt">sand</span> samples and completed 4,999 interviews. Adjusted odds ratios (aORs) were computed, comparing those in the highest tertile of fecal indicator exposure with those who reported no <span class="hlt">sand</span> contact. Among those digging in <span class="hlt">sand</span> compared with those not digging in <span class="hlt">sand</span>, a molecular measure of Enterococcus spp. (calibrator cell equivalents/g) in <span class="hlt">sand</span> was positively associated with gastrointestinal (GI) illness (aOR = 2.0 [95% confidence interval (CI) = 1.2–3.2]) and diarrhea (2.4 [1.4–4.2]). Among those buried in <span class="hlt">sand</span>, point estimates were greater for GI illness (3.3 [1.3–7.9]) and diarrhea (4.9 [1.8–13]). Positive associations were also observed for culture-based Enterococcus (colony-forming units/g) with GI illness (aOR digging = 1.7 [1.1–2.7]) and diarrhea (2.1 [1.3–3.4]). Associations were not found among non-swimmers with <span class="hlt">sand</span> exposure. Conclusions We observed a positive relationship between <span class="hlt">sand</span> contact activities and enteric illness as a function of concentrations of fecal microbial pollution in beach <span class="hlt">sand</span>. PMID:22157306</p> <div class="credits"> <p class="dwt_author">Heaney, Christopher D.; Sams, Elizabeth; Dufour, Alfred P.; Brenner, Kristen P.; Haugland, Richard A.; Chern, Eunice; Wing, Steve; Marshall, Stephen; Love, David C.; Serre, Marc; Noble, Rachel; Wade, Timothy J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1992JGR....9720249A"> <span id="translatedtitle">Velocity observations above a rippled <span class="hlt">bed</span> using laser Doppler velocimetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Velocity observations are reported in a plane across a regular nonmigrating ripple in 2.5 m of water depth. The forcing was weak, primarily wave-induced near-<span class="hlt">bed</span> orbital motion. The data were acquired using a two-axis submerged laser Doppler velocimeter. Synchronous records of pressure below the surface were also obtained. The instrumentation is described. The pressure information was used to separate wave-coherent and turbulence motion in the observed velocity. Turbulent kinetic energy and dissipation rates are obtained over a range of distances above the <span class="hlt">bed</span> from 1.5 mm above the ripple to 10 cm. Velocity time series are smooth except at high-velocity magnitudes, indicating the formation of a lee vortex during peak velocities only. The data show convective acceleration of the flow over the ripple and a lack of significant shear in the rms horizontal motion farther from the <span class="hlt">bed</span>. Velocity spectra at one location, 1.5 mm from the <span class="hlt">bed</span> show second and third harmonics of the incident wave, which are interpreted to be due to convective acceleration over the ripple and vortex shedding. High-frequency velocity spectra show uniformly decreasing turbulence intensity away from the <span class="hlt">bed</span>. We conclude that the boundary layer observed here was transitional, i.e., laminar through small velocity periods, becoming turbulent for short periods during which the breakup of the vortex shed by the ripples occurred. Laminar estimates of maximum bottom friction are consistent with the threshold for initiation of motion criterion for 0.2 mm <span class="hlt">sand</span> and the observed ripple steepness.</p> <div class="credits"> <p class="dwt_author">Agrawal, Y. C.; Aubrey, D. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1061/40926(239)196"> <span id="translatedtitle">A rapid compatibility analysis of potential offshore <span class="hlt">sand</span> sources for beaches of the Santa Barbara Littoral Cell</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The beaches of the Santa Barbara Littoral Cell, which are narrow as a result of either natural and/or anthropogenic factors, may benefit from nourishment. <span class="hlt">Sand</span> compatibility is fundamental to beach nourishment success and grain size is the parameter often used to evaluate equivalence. Only after understanding which <span class="hlt">sand</span> sizes naturally compose beaches in a specific cell, especially the smallest size that remains on the beach, can the potential compatibility of source areas, such as offshore borrow sites, be accurately assessed. This study examines sediments on the beach and in the nearshore (5-20m depth) for the entire Santa Barbara Littoral Cell east of Point Conception. A digital <span class="hlt">bed</span> sediment camera, the Eyeball??, and spatial autocorrelation technique were used to determine sediment grain size. Here we report on whether nearshore sediments are comparable and compatible with beach <span class="hlt">sands</span> of the Santa Barbara Littoral Cell. ?? 2007 ASCE.</p> <div class="credits"> <p class="dwt_author">Mustain, N.; Griggs, G.; Barnard, P. L.</p> <p class="dwt_publisher"><