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1

Spatial differences in aeolian erosion of arid silty- sand soils due to surface features  

NASA Astrophysics Data System (ADS)

The significance of soil erosion by wind is substantial by means of soil degradation and air pollution. There is still a gap in quantifying the aeolian soil erosion in response to changes in surface features. The aim of this study is to quantify the aeolian erosion of silty-sand soil in an arid region (Yamin Plateau, Negev, Israel) under different wind and surface conditions. The study was conducted in experimental plots of sparse vegetation (SV), rock fragment (RF), and mechanical crust (MC) under natural and disturbed soil surfaces. Aeolian simulations were executed through the use of a portable wind tunnel with different wind speeds. Variables measured during the simulations include wind profile and shear stress, horizontal sand flux (saltation), vertical flux of total aeolian sediments (TAS), and concentration of PM10 (particle less than 10 micrometers in diameter). The results show that during experiments at 6 and 11 m/s in natural soil surface, the cumulative PM10 concentration (mg/m3) in plot MC was 5 and 6.8 times higher than in plots RF and SV, respectively. Soil loss calculation for PM10 at these wind speed in natural surface shows that the soil at plot MC was the most available for erosion with a loss of 253 and 1530 mg/m2 (7 minutes), respectively. This is 2 and 6 times higher than in plots SV and RF, respectively. The impact of soil surface disturbance was more significant in plot MC under wind speed of 6 m/s and in plot RF under wind speed of 11 m/s. Soil loss calculation for sand (> 100 µm) at speed of 6 m/s in natural surface shows that the loss at plot MC was 2 and 5.8 times higher than in plots RF and SV, respectively. The results indicate on spatial differences in the aeolian erosion of silty - sand soil in response to changes in wind speed and surface characteristics.

Edri, Avi; Katra, Itzhak; Avraham, Dody

2014-05-01

2

Transport and transformation of sulfadiazine in soil columns packed with a silty loam and a loamy sand  

NASA Astrophysics Data System (ADS)

Concerning the transport of the veterinary antibiotic sulfadiazine (SDZ) little is known about its possible degradation during transport. Also its sorption behaviour is not yet completely understood. We investigated the transport of SDZ in soil columns with a special emphasis on the detection of transformation products in the outflow of the soil columns and on modelling of the concentration distribution in the soil columns afterwards. We used disturbed soil columns near saturation, packed with a loamy sand and a silty loam. SDZ was applied as a 0.57 mg L - 1 solution at a constant flow rate of 0.25 cm h - 1 for 68 h. Breakthrough curves (BTC) of SDZ and its transformation products 4-(2-iminopyrimidin-1(2 H)-yl)aniline and 4-hydroxy-SDZ were measured for both soils. For the silty loam we additionally measured a BTC for an unknown transformation product which we only detected in the outflow samples of this soil. After the leaching experiments the 14C-concentration was quantified in different layers of the soil columns. The transformation rates were low with mean SDZ mass fractions in the outflow samples of 95% for the loamy sand compared to 97% for the silty loam. The formation of 4-(2-iminopyrimidin-1(2 H)-yl)aniline appears to be light dependent and did probably not occur in the soils, but afterwards. In the soil columns most of the 14C was found near the soil surface. The BTCs in both soils were described well by a model with one reversible (kinetic) and one irreversible sorption site. Sorption kinetics played a more prominent role than sorption capacity. The prediction of the 14C -concentration profiles was improved by applying two empirical models other than first order to predict irreversible sorption, but also these models were not able to describe the 14C concentration profiles correctly. Irreversible sorption of sulfadiazine still is not well understood.

Unold, M.; Kasteel, R.; Groeneweg, J.; Vereecken, H.

2009-01-01

3

Numerical evaluation of seismic response of shallow foundation on loose silt and silty sand  

NASA Astrophysics Data System (ADS)

This study includes the results of a set of numerical simulations carried out for sands containing plastic/non-plastic fines, and silts with relative densities of approximately 30-40% under different surcharges on the shallow foundation using FLAC 2D. Each model was subjected to three ground motion events, obtained by scaling the amplitude of the El Centro (1940), Kobe (1995) and Kocaeli (1999) Q12earthquakes. Dynamic behaviour of loose deposits underlying shallow foundations is evaluated through fully coupled nonlinear effective stress dynamic analyses. Effects of nonlinear soil structure interaction (SSI) were also considered by using interface elements. This parametric study evaluates the effects of soil type, structure weight, liquefiable soil layer thickness, event parameters (e.g., moment magnitude of earthquake ( M w ), peak ground acceleration PGA, PGV/PGA ratio and the duration of strong motion ( D 5-95) and their interactions on the seismic responses. Investigation on the effects of these parameters and their complex interactions can be a valuable tool to gain new insights for improved seismic design and construction.

Asgari, Ali; Golshani, Aliakbar; Bagheri, Mohsen

2014-03-01

4

Behavior of Nonplastic Silty Soils under Cyclic Loading  

PubMed Central

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results.

Ural, Nazile; Gunduz, Zeki

2014-01-01

5

Experience in constructing radial wells in fine sands  

Microsoft Academic Search

The grounds of the plant where the tests of radial drainage were conducted were characterized bythe wide development of inhomogeneous fine sands containing discontinuous layers and lenses of yellow-gray and light-gray compact clay with a thickness from 0.4 to 5.0 m or its thinner interlayers. Along with this, ferruginous sandstone interlayers are found in the fine sands. Genetically the sands

V. E. Anpilov; Yu. V. Ponomarenko; V. P. Lugovoi; V. S. Kuz'kin; F. S. Malatskovskii

1982-01-01

6

Efficiency of Micro-fine Cement Grouting in Liquefiable Sand  

SciTech Connect

In the presence of strong ground motion, liquefaction hazards are likely to occur in saturated cohesion-less soils. The risk of liquefaction and subsequent deformation can be reduced by various ground improvement methods including the cement grouting technique. The grouting method was proposed for non-disruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. In this research, a large-scale experiment was developed for assessment of micro-fine cement grouting effect on strength behavior and liquefaction potential of loose sand. Loose sand samples treated with micro-fine grout in multidirectional experimental model, were tested under cyclic and monotonic triaxial loading to investigate the influence of micro-fine grout on the deformation properties and pore pressure response. The behavior of pure sand was compared with the behavior of sand grouted with a micro-fine cement grout. The test results were shown that cement grouting with low concentrations significantly decreased the liquefaction potential of loose sand and related ground deformation.

Mirjalili, Mojtaba [Dept. of Civil and Earth Resources Eng., Graduate School of Eng., Kyoto University, Kyoto 615-8540 (Japan); Mirdamadi, Alireza; Ahmadi, Alireza [Faculty of Civil Eng, University College of Eng, University of Tehran, Tehran (Iran, Islamic Republic of)

2008-07-08

7

Atrazine Persistence in a Valentine Loamy Fine Sand Profile.  

National Technical Information Service (NTIS)

The persistence data indicate that atrazine dissipation in irrigated Valentine loamy fine sand occurs at a rate greatly exceeding that expected for this soil texture. Atrazine is rapidly degraded in the top 6 inches of soil and mobility data show that the...

R. H. Hammons

1977-01-01

8

Modeling downstream fining in sand-bed rivers. I: Formulation  

USGS Publications Warehouse

In this paper a numerical modeling formulation is presented for simulation of the development of the longitudinal profile and bed sediment distribution in sand-bed rivers. The objective of the model application, which is presented in the companion paper (Wright and Parker, 2005), is to study the development of two characteristics of large, low-slope, sand-bed rivers: (1) a downstream decrease in bed slope (i.e. concave upward longitudinal profile) and (2) a downstream decrease in characteristic bed sediment diameter (e.g. the median bed surface size D50). Three mechanisms that lead to an upward concave profile and downstream fining are included in the modeling formulation: (1) a delta prograding into standing water at the downstream boundary, (2) sea-level rise, and (3) tectonic subsidence. In the companion paper (Wright and Parker, 2005) the model is applied to simulate the development of the longitudinal profile and downstream fining in sand-bed rivers flowing into the ocean during the past 5000 years of relatively slow sea-level rise. ?? 2005 International Association of Hydraulic Engineering and Research.

Wright, S.; Parker, G.

2005-01-01

9

Nature and fate of oil sands fine tailings  

SciTech Connect

The chemical and physical properties of clay suspensions produced during oil production front oil sands are described. With a composition of approximately 70 wt% water (with some unrecovered bitumen) and 30 wt% solids (>90% less than 44 {mu}m in size), these clay suspensions consolidate very slowly. Clay aggregate or floc morphology has been shown to be a function of the water chemistry and can be manipulated to produce a tailings suspension that is easier to consolidate and dewater. Commercial oil sands processing has been going on in northeastern Alberta since 1967, and in that time approximately 250 million m of this difficult to dewater clay suspension has been produced. The reclamation options for this material (mature fine tailings) on a commercial scale are also outlined. 84 refs., 36 figs., 3 tabs.

Mikula, R.J.; Kasperski, K.L. [Western Research Centre, Devon, Alberta (Canada); Burns, R.D. [Suncor Oil Sands Group, Alberta (Canada); MacKinnon, M.D. [Syncrude Canada Ltd., Edmonton, Alberta (Canada)

1996-12-31

10

Modeling downstream fining in sand-bed rivers. II: Application  

USGS Publications Warehouse

In this paper the model presented in the companion paper, Wright and Parker (2005) is applied to a generic river reach typical of a large, sand-bed river flowing into the ocean in order to investigate the mechanisms controlling longitudinal profile development and downstream fining. Three mechanisms which drive downstream fining are studied: a delta prograding into standing water, sea-level rise, and tectonic subsidence. Various rates of sea-level rise (typical of the late Holocene) and tectonic subsidence are modeled in order to quantify their effects on the degree of profile concavity and downstream fining. Also, several other physical mechanisms which may affect fining are studied, including the relative importance of the suspended versus bed load, the effect of the loss of sediment overbank, and the influence of the delta bottom slope. Finally, sensitivity analysis is used to show that the grain-size distribution at the interface between the active layer and substrate has a significant effect on downstream fining. ?? 2005 International Association of Hydraulic Engineering and Research.

Wright, S.; Parker, G.

2005-01-01

11

PREPACK TECHNIQUE USING FINE SAND IMPROVES RESULTS OF FRACTURING AND FRACTURE ACIDIZING TREATMENTS  

Microsoft Academic Search

Dowell Division of Dow Chemical Co. describes the possible mechanisms by which 100-mesh sand used in a prepack stage greatly improves the results of stimulation treatments in various types of formations. Some of the observations made when this fine sand is used in fracturing and acidizing treatments are a higher sustained production, lower injection rates, higher concentration of conventional proppant,

B. D. Miller; P. A. Warembourg

1975-01-01

12

The Stabilization of Silty Soils.  

National Technical Information Service (NTIS)

For the purpose of confirming and possibly modifying the predicted conclusions of a laboratory study to find a suitable means of stabilizing silty soils in Rhode Island, previously reported, a test road was constructed and its performance evaluated. A tes...

V. A. Nacci K. Moultrop M. C. Wang M. T. Huston

1973-01-01

13

Experimental Study of the Possibility to Make a Mortar with Ternary Sand (Natural and Artificial Fine Aggregates)  

NASA Astrophysics Data System (ADS)

This experimental study investigates the possibility to make a mortar with a ternary sand (natural and artificial fine aggregates). This method is utilized to correct the particle size distribution of various sands used in mortar. For this investigation, three sands have been used: a dune sand (DS), a slag sand (SS), and brick sand (BS) at different proportions in mortar. After crushing, the artificial fine aggregate (blast furnace slag and waste brick fine aggregate) was sifted in order to use it as fine aggregate. The effect of the quality and grain size distribution of natural fine aggregate (i.e., DS) and artificial fine aggregates (i.e., SS and BS) on the physical properties of ternary sand confected (density, porosity, fineness modulus, equivalent sand, particle size distribution, water absorption) and properties of fresh and hardened mortar were analysed. In the same way for this study, the physical properties and chemical compositions of DS, SS, BS and cement were investigated. The results obtained show that the mechanical strength on mortar depends of the nature and particle size distribution of sand studied. The reuse of this recycled material (slag blast furnace and waste brick) in the industry would contribute to the protection of the environment. This study shows the potential of this method to make mortar with ternary sand (natural and artificial fine aggreagates) in order to improve the physical properties of sand. Utilising natural and artificial fine aggregates to produce quality mortar should yield significant environmental benefits.

Baali, L.; Naceri, A.; Rahmouni, Z.; Mehidi, M. W. Noui

14

Coal-sand attrition system and its importance in fine coal cleaning. Final report  

SciTech Connect

It is known that ultra-fine coals are prerequisite for the deep cleaning of most US coal seams if environmental pollution arising from the use of such coals is to be minimized. Therefore, the production of finely liberated coal particles in conjunction with reduced heavy metal contaminants at low costs is desirable, if not mandatory. The liberation of intimately disseminated impurities from the coal matrix therefore, demands that the material be ground to a high degree of fineness. Similarily, some technologies for coal utilization require superfine particles (i.e., sizes less than ten microns). This implies additional costs for coal preparation plants due to the high energy and media costs associated with fine grinding operations. Besides, there are problems such as severe product contaminations due to media wear and impairment of the quality of coal. Hence, proper choice of grinding media type is important from the viewpoints of cost reduction and product quality. The use of natural quartz sand as grinding media in the comminution of industrial minerals in stirred ball mills has been indicated. The advantages of natural sand compared to steel media include low specific energy inputs, elimination of heavy metal contaminants and low media costs. In this work, the effect of rotor speed, solids concentration and feed-size are studied on four coals in conjunction with silica sand and steel shot. The results obtained are used to evaluate the suitability of silica sands as an alternative grinding media. for coal. Coal-sand and coal-steel systems are compared in terms of specific energy consumption, product fineness, media/wear contaminationanalysis and calorific values, liberation spectrum and particle shape characteristics. In general cleaner flotation concentrate was obtained from coals when they were ground with sand media. The zeta potential of coals was found to be different and lower when they ground with sand.

Mehta, R.K.; Zhu, Qinsheng

1993-08-01

15

Effect of polyvinyl acetate grout injection on geotechnical properties of fine sand  

Microsoft Academic Search

This laboratory project aims to investigate the influence of polyvinyl acetate (PVA) grout injection on sandy soil improvement. In order to make the polymeric material injectable through the soil particles, adhesive polymer is mixed with water in certain weight percentages. Fine grained sand with different dry densities in its loose, medium and dense state, is prepared in a cylindrical mould

Rassoul Ajalloeian; Hossein Matinmanesh; Sayyed Mahdi Abtahi; Mohammadali Rowshanzamir

2012-01-01

16

The prediction of equivalent granular steady state line of loose sand with fines  

Microsoft Academic Search

Void ratio has been used as a state variable for predicting the liquefaction behaviour of soils under the critical state, sometimes also referred to as the steady state, framework. Recent publications show that void ratio may not be a good parameter for characterising sand with fines because the steady state line (or curve) in the e-log(p?) space moves downward with

M. M. Rahman; S. R. Lo

2008-01-01

17

Liquefaction in silty soils—screening and remediation issues  

Microsoft Academic Search

Current techniques for liquefaction screening, ground modification for liquefaction mitigation, and post-improvement verification rely on knowledge gained from extensive research on clean sands, field observations of liquefied ground, and judicial correlation of normalized penetration resistance [(N1)60,qc1N] or shear wave velocity (vs1) data with field liquefaction observations. Uncertainties prevail on the direct extrapolation of such techniques for silty soil sites. This

S Thevanayagam; G. R Martin

2002-01-01

18

Absence of shape sorting of fine sand by the braided William-River, northern Saskatchewan  

SciTech Connect

Sorting of sedimentary particles on the basis of shape is one of many mechanisms by which the characteristics of sediment samples may change along a transport path. The question of the importance of shape sorting of fine sand in fluvial systems is unresolved, due mainly to the difficulty of adequately measuring shape of small particles with irregular morphology, and eliminating other shape influencing processes primarily multiple sources. The study area and analytical techniques were chosen to eliminate these two problems. The William River, a braided river in northern Saskatchewan, is constructing a delta into Lake Athabasca. The 5 km supradeltaic portion of the stream receives no sediment other than from the single fluvial source. 400-500 quartz particles within the fine sand fraction (180-250 microns) of 15 stream samples were analyzed via Fourier techniques. Results indicate that braided river transport processes do not selectively transport fine sand particles on the basis of shape, either at gross scale (elongation) or smaller scale surface roughness. Littoral drift processes, in contrast, have been shown to select on the basis of both elongation and surface roughness. The differences in shape selectivity may be due to transport by traction versus suspension. Analysis should, however, be extended to other grain sizes.

Kennedy, S.K.

1985-01-01

19

Mature fine tailings from oil sands processing harbour diverse methanogenic communities.  

PubMed

Processing oil sands to extract bitumen produces large volumes of a tailings slurry comprising water, silt, clays, unrecovered bitumen, and residual solvent used in the extraction process. Tailings are deposited into large settling basins, where the solids settle by gravity to become denser mature fine tailings (MFT). A substantial flux of methane, currently estimated at ~40 million L/day, is being emitted from the Mildred Lake Settling Basin. To better understand the biogenesis of this greenhouse gas, the methanogenic consortia in MFT samples from depth profiles in 2 tailings deposits (Mildred Lake Settling Basin and West In-Pit) were analyzed by constructing clone libraries of amplified archaeal and bacterial 16S rRNA genes. The archaeal sequences, whose closest matches were almost exclusively cultivated methanogens, were comparable within and between basins and were predominantly (87% of clones) affiliated with acetoclastic Methanosaeta spp. In contrast, bacterial clone libraries were unexpectedly diverse, with the majority (~55%) of sequences related to Proteobacteria, including some presumptive nitrate-, iron-, or sulfate-reducing, hydrocarbon-degrading genera (e.g., Thauera, Rhodoferax, and Desulfatibacillum). Thus, MFT harbour a diverse community of prokaryotes presumptively responsible for producing methane from substrates indigenous to the MFT. These findings contribute to our understanding of biogenic methane production and densification of MFT in oil sands tailings deposits. PMID:20657616

Penner, Tara J; Foght, Julia M

2010-06-01

20

Phytotoxicity and naphthenic acid dissipation from oil sands fine tailings treatments planted with the emergent macrophyte Phragmites australis  

Microsoft Academic Search

During reclamation the water associated with the runoff or groundwater flushing from dry stackable tailings technologies may become available to the reclaimed environment within an oil sands lease. Here we evaluate the performance of the emergent macrophyte, common reed (Phragmites australis), grown in chemically amended mature fine tailings (MFT) and simulated runoff\\/seepage water from different MFT drying treatments. The present

Sarah A. Armstrong; John V. Headley; Kerry M. Peru; Randy J. Mikula; James J. Germida

2010-01-01

21

Sand  

NSDL National Science Digital Library

This site provides an introduction to sand, a size fraction of what is commonly known as sediment (along with gravel, silt, and clay). An introductory section discusses the sedimentary aspects (grain size, rounding, and sorting), composition, and texture of sand. There is a virtual collection of sand specimens, sorted by location, region, or color. Each photo can be zoomed in or out and is accompanied by a brief description of the specimen. There is also a geographical index of specimens from the virtual collection which uses an interactive map to display them. An exercise is provided which uses specimens from the virtual collection to help students develop a connection between certain characteristics of sands and their environment of formation, information which can be applied to inferring the depositional environments of ancient sandstones. Other materials include a sand discovery kit, created to help teachers use sand in their classrooms, a 'Sands of the World' poster, and links to related websites. Some of these items must be purchased.

22

Effect of Salt on the Flocculation Behavior of Nano Particles in Oil Sands Fine Tailings  

Microsoft Academic Search

Currently, two commercial plants, operating in the Athabasca region of Alberta, produce approximately 20 percent of Canada's petroleum requirements from oil sands. Surface mined oil sand is treated in a water based separation process that yields large volumes of clay tailings with poor settling and compaction characteristics. Clay particles, suspended in the pond water, interact with salts, dissolved from the

L. S. Kotylar; B. D. SPARKS; R. SCHUTFE

1996-01-01

23

Modeling fine-scale geological heterogeneity--examples of sand lenses in tills.  

PubMed

Sand lenses at various spatial scales are recognized to add heterogeneity to glacial sediments. They have high hydraulic conductivities relative to the surrounding till matrix and may affect the advective transport of water and contaminants in clayey till settings. Sand lenses were investigated on till outcrops producing binary images of geological cross-sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non-stationary patterns on section images that hamper subsequent simulation. Transition probability (TP) and multiple-point statistics (MPS) were employed to simulate sand lens heterogeneity. We used one cross-section to parameterize the spatial correlation and a second, parallel section as a reference: it allowed testing the quality of the simulations as a function of the amount of conditioning data under realistic conditions. The performance of the simulations was evaluated on the faithful reproduction of the specific geological structure caused by sand lenses. Multiple-point statistics offer a better reproduction of sand lens geometry. However, two-dimensional training images acquired by outcrop mapping are of limited use to generate three-dimensional realizations with MPS. One can use a technique that consists in splitting the 3D domain into a set of slices in various directions that are sequentially simulated and reassembled into a 3D block. The identification of flow paths through a network of elongated sand lenses and the impact on the equivalent permeability in tills are essential to perform solute transport modeling in the low-permeability sediments. PMID:23252428

Kessler, Timo Christian; Comunian, Alessandro; Oriani, Fabio; Renard, Philippe; Nilsson, Bertel; Klint, Knud Erik; Bjerg, Poul Løgstrup

2013-01-01

24

Phytotoxicity and naphthenic acid dissipation from oil sands fine tailings treatments planted with the emergent macrophyte Phragmites australis.  

PubMed

During reclamation the water associated with the runoff or groundwater flushing from dry stackable tailings technologies may become available to the reclaimed environment within an oil sands lease. Here we evaluate the performance of the emergent macrophyte, common reed (Phragmites australis), grown in chemically amended mature fine tailings (MFT) and simulated runoff/seepage water from different MFT drying treatments. The present study also investigated the phytotoxicity of the concentration of oil sands naphthenic acids (NAs) in different MFT drying chemical treatments, in both planted and unplanted systems. We demonstrate that although growth was reduced, the emergent macrophyte common reed was capable of growing in diluted unamended MFT runoff, as well as in diluted runoff from MFT amended with either 0.25% lime and gypsum or 0.5% gypsum. Common reed can thus assist in the dewatering process of oil sands MFT. However, simulated runoff or seepage waters from chemically amended and dried MFT were phytotoxic, due to combined levels of salts, naphthenic acids and pH. Phytoremediation of runoff water/ground water seepage from dry-land applied MFT will thus require pre-treatment in order to make conditions more favorable for plant growth. PMID:20486009

Armstrong, Sarah A; Headley, John V; Peru, Kerry M; Mikula, Randy J; Germida, James J

2010-01-01

25

Water Level Detection in Silty Materials Using Ground Penetrating Radar  

Microsoft Academic Search

Detection of water level in silty soils can be complicated because of capillary action. In this study, the water level in a silty soil sample was detected using Ground Penetrating Radar (GPR) technique in the laboratory. The soil sample has dimensions of 62 cm × 48 cm × 46 cm and was kept in a clear Plexiglas container which facilitated

Udaya B. Halabe; Hema J. Siriwardane; Sandeep Pyakurel; Ricardo Kiriakidis; Ronald Ingram

2007-01-01

26

Experimental and numerical understanding of a splashing drop onto fine sand samples  

NASA Astrophysics Data System (ADS)

Water erosion phenomenons are increasingly studied and understood but raindrop erosion is far more complex. Raindrop erosion includes subprocesses such as impact, cratering, rim formation, daughter drop splash and soil particle splash. This work is focused on modeling complex ballistic trajectories of soil particle splashes and particle dispersion process. The general purpose is first to recreate the splash effect in laboratory and second to provide optimal numerical models and a better understanding of the soil particle splash. Since the complex multiphase interactions are difficult to model, it is easier to compute numerically the dispersion process. Physical based models are the most common approach in this investigation field. The first assumption is that the crater shape might be the controlling factor in the dispersion process governed by the average splash distance. Moreover, complex physical based models may govern ballistic trajectories. These assumptions have now to be proven. Phenomenological observations are given by experiments in laboratory, on a setup inspired by Furbish et al. (2007) study. Fine soil samples are used in this work and advanced grain size analysis is performed using laser diffraction technique. High-speed camera acquisitions and micro-LiDAR records are used throughout experimental investigations. Then, impact velocities are measured as well as crater shape or particle dispersion. Measured velocities tend to be close to those computed by numerical simulations. High-speed photography analysis shows that the mean initial splash angle is dependent on the drop penetration depth. Moreover, the mean splash angle seems to be dependent on the slope at the crater edge. Numerical computation is then performed to model the dispersion phenomenon. Using a probabilistic algorithm, the grain size distribution can be taken into account throughout numerical simulation. The initial splash angle mean value is derived from previous assumption about the key role of the crater shape. Gravity, drag and buoyant forces are also taken into account. Model validation is performed by comparisons between experimental and numerical results using digitalized experimental dispersion photography and LiDAR scanning. Further perspectives should be oriented in multiphase interactions (fluid to soil particle) for a better understanding of the whole phenomenon.

Wyser, Emmanuel; Rudaz, Benjamin; Jaboyedoff, Michel

2014-05-01

27

Using an Integrated, Remote-Sensing Methodology to Evaluate the Effects of Dam Operations on Fine-Grained Sediment Storage and Sand Bar Restoration in Marble Canyon  

NASA Astrophysics Data System (ADS)

Eddy sand bars 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. These deposits began eroding following the 1963 closure of Glen Canyon Dam that reduced the supply of sand at the upstream boundary of GCNP by about 94 % and are still eroding today. In the 1990s, resource managers and scientists began a long series of experiments and monitoring aimed at answering one primary science question. Given existing sand inputs to the ecosystem, can any set of dam operations actually restore and maintain sand bars within the Canyon? In order to test this question, a reach-based approach was developed to examine temporal and longitudinal trends in sediment storage and composition in six, 3 to 6-km reaches of the channel in Eastern GCNP. The reach-based approach integrates various remote-sensing technologies to supplement historical survey techniques. These include: LiDAR and multi-beam sonar for measuring the elevations of subaerial and subaqueous surfaces; an underwater microscope (the flying eyeball) and its subaerial sister, the beachball, for measuring the composition of sediment surfaces; and traditional surveys to provide fine-level control. Between 2000-2005, 7 distinct measurements were made for all reaches. These bracketed two high-flow experiments (controlled floods) and intermediate periods characterized by normal Dam operations. Sediment-surface changes will allow scientists to quantify system responses to specific Dam operations in attempting to address the primary science question.

Breedlove, M. J.; Hazel, J. E.; Kaplinski, M. A.; Schmidt, J. C.; Topping, D. J.; Rubin, D. M.; Fuller, A. E.; Tusso, R.; Gonzales, F. M.

2005-12-01

28

Reservoir characteristics of two minter oil sands based on continuous core, E-logs, and geochemical data: Bee Brake field, East-Central Louisiana  

SciTech Connect

The Bee Brake field area, located in township 4N/6E and 4N/7E in Concordia Parish, has been one of the more prolific oil-producing areas in east-central Louisiana. Production decline in various fields, however, has sparked interest in the economic feasibility of locating and producing the remaining bypassed oil in the lower Wilcox. For this purpose, the Angelina BBF No. 1 well was drilled, and a 500-ft conventional core and a complete suite of state-of-the-are wireline logs were recovered. Production tests were run on the Minter interval of interest. The 16-ft Minter interval (6742-6758 ft depth), bounded at its top and base by lignite seams, consists of an upper 4-ft oil sand (Bee Brake) and a lower 3-ft oil sand (Angelina). The oil sands are separated by approximately 5 ft of thinly laminated silty shale and 4 ft of very fine-grained silty sandstone. Detailed sedimentologic and petrographic descriptions of the Minter interval provide accurate facies determinations of this lower delta-plain sequence. Petrophysical evaluation, combining core plug and modern electric-log data show differences between reservoir quality of the Bee Brake and Angelina sands. This data will also be useful for correlating and interpolating old electric logs. Organic geochemistry of the oil, lignites, and shales provides insight as to the source of the Minter oils and the sourcing potential of the lignites.

Echols, J.B.; Goddard, D.A.; Bouma, A. (Louisiana State Univ., Baton Rouge, LA (United States))

1993-09-01

29

A study of infiltration on three sand capillary barriers  

Microsoft Academic Search

The capillary barrier effect was investigated by conducting infiltration tests on three soil columns of fine sand over medium sand, medium sand over gravelly sand, and fine sand over gravelly sand. The barrier effect was ver- ified in the underlying layer of coarser material, and the water-entry values of the coarser layers were confirmed to be nearly equal to the

Hong Yang; H. Rahardjo; E. C. Leong; D. G. Fredlund

2004-01-01

30

Upper Cretaceous bioturbated fine-to-medium sands: A problem for deep-water exploration in Campos Basin, Offshore Brazil  

SciTech Connect

The presence of bioturbation in oil-prone turbidite deposits has detained a better exploration of upper Cretaceous siliciclastic reservoirs in Campos Basin. Bioturbated sandstones have degraded their permo-porosity with impact in oil production. They occur associated to unbioturbated sandstones with similar seismic amplitude, becoming difficult to separate them in seismic mapping. A comprehensive study in order to reduce the exploratory risk must consider firstly the recognition of genetic facies association through cores, and secondly the calibration of sonic well-logs and seismic velocity sections with rock data. This study deals with sedimentary facies association. The range of main facies in such reservoirs includes: (1) medium-to-coarse siliciclastic sandstone with cross stratification; (2) fine-to-medium massive sandstone with thin traction carpets, bioturbated by opportunistic ichnofabrics and, (3) bioturbated, muddy, fine-to-medium, quartz-feldspatic and glauconitic sandstone over 60 in thick. The genetic facies associations suggest that the sandwich reservoirs were formed by high density turbidite currents deposited en masse or by thin traction carpets. The bioturbated sandstone was originated by reworking of bottom currents rich in nutrients and oxygen. Detritic and biogenic glauconite covered and/or filled bioturbations indicate a basinward movement of the bottom currents. The successive alternation of high-energy with low-energy ichnofabrics reflects cyclic variations in current velocities.

Carminatti, M.; Zimmermann, L.; Jahnert, R.; Pontes, C.

1996-08-01

31

Assessment of the Mechanical Properties of Sisal Fiber-Reinforced Silty Clay Using Triaxial Shear Tests  

PubMed Central

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10?mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

Wu, Yankai; Li, Yanbin; Niu, Bin

2014-01-01

32

Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.  

PubMed

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10?mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment. PMID:24982951

Wu, Yankai; Li, Yanbin; Niu, Bin

2014-01-01

33

Research on the Quaternary Fine-fraction Lithofacies and Sedimentation Model in Tainan Area, Qaidam Basin  

NASA Astrophysics Data System (ADS)

The Quaternary Sebei formation is a type of lacustrine deposit developed in the center of depressed lake basin with low-dipping dome-shaped inherited geomorphological environment in Tainan area, Qaidam Basin. The sedimentary strata are composed of weakly consolidated silty to fine-grained sandstone and mudstone. In this article, data obtained from the special coring analysis under sealing high-pressure nitrogen method were used to study the lithofacies. It is proved that seven types of lithofacies and five types of facies association could be classified in the Quaternary Sebei Formation in the Tainan Area. Accordingly, three types of microfacies (sometimes called energy units) could be acquired, including sandbars, beach sands, and mud flats. These three types of microfacies are orderly distributed. The sandbars are concentrated on the higher portion of the dome and close to the low water level of the lake. The beach sands are concentrated on the flanks of the dome and below the low water level of the lake. The sandbars are always intercalated with the beach sands. The mud flats are concentrated in the synclinal part and could extend to the entire area when the level of the lake water moved relatively upwards. The physical property of the sandbars is better than that of the beach sands, and the homogeneity of the sandbars are better than that of the beach sands. The mud flat acts not only as the source of the biogenic gas but also as the infiltrating barrier of the natural gas.

XIE, Zongkui

34

A TOXICITY IDENTIFICATION EVALUATION OF SILTY MARINE HARBOR SEDIMENTS TO CHARACTERIZE PERSISTENT AND NON-PERSISTENT CONSTITUENTS  

EPA Science Inventory

Sediment toxicity in silty marine harbor sediments is frequently dominated by ammonia or sulfide, leaving the adverse effects of persistent toxic substances unnoticed. To investigate the latter, we subjected interstitial water from three contaminated silty sediments to toxicity i...

35

Using an Integrated, Remote-Sensing Methodology to Evaluate the Effects of Dam Operations on Fine-Grained Sediment Storage and Sand Bar Restoration in Marble Canyon  

Microsoft Academic Search

Eddy sand bars 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. These deposits began eroding following the 1963 closure of Glen Canyon Dam that reduced the supply of sand at the upstream

M. J. Breedlove; J. E. Hazel; M. A. Kaplinski; J. C. Schmidt; D. J. Topping; D. M. Rubin; A. E. Fuller; R. Tusso; F. M. Gonzales

2005-01-01

36

Petrophysical and textural characteristics of thin-bedded turbidite sands, Miocene Mt. Messenger formation, Taranaki Peninsula, New Zealand  

SciTech Connect

The Mt. Messenger Formation exposed along the Taranaki coastline (North Island) and in nearby producing oil fields is 600 meters thick and consists of a turbidite sequence deposited in a foredeep trough adjacent to a relatively narrow shelf in lower to upper bathyal water depths. Gamma-ray values of {open_quote}Thick-bedded{close_quote} sands greater than 15 cm thick on the outcrop are less than 175 counts per second (cps). These sandstones have the highest permeability values (100-800 mD). {open_quote}Thin-bedded{close_quotes} sands (5-15 cm) have values greater than 175 cps and range from 200-600 mD. {open_quote}Very Thin-bedded{close_quote} sands (less than 5 cm) range from 10-200 mD; gamma-ray values are impossible to resolve on the outcrop. Gamma-ray values in claystones exceed 250 cps. Lower very fine to silty sands (upper part of sequence) have significantly lower permeabilities because of sorting and the presence of mica and clay. A typical cored section through a pay interval consists of an upper 10-meter interval with average pay thickness of 17.5 cm (44% of the beds are greater than 20 cm thick and permeabilities average 144 mD) and a lower 20 m thick interval containing thinner pay sands (average 12.5 cm and only 22% of the beds are greater than 20 cm thick). Permeabilities average 130 mD. Thirty-seven percent of the interval contains pay sand and the remainder is claystones or non-pay sand. Interbedded thin-bedded water and oil-bearing sands have similar permeabilities and capillary properties. Clean, wet sands have less clay or feldspar and a lower gamma ray count than sands containing oil. The cause for wet sands interbedded with oil sands in the subsurface appears to be isolation and early sealing (microcompartmentalization) of sands by claystones. These features are observed in the coastal exposures.

Douglas, J.W. [ARCO International Oil and Gas Company, Plano, TX (United States); King, P.R.; Browne, G.H. [Institute of Geological and Nuclear Science, Lower Hutt (New Zealand)

1995-08-01

37

Coal-sand attrition system and its' importance in fine coal cleaning. Eighth quarterly report, June 1, 1992--August 31, 1993.  

National Technical Information Service (NTIS)

The research efforts on the importance of a coal-sand attrition continued with work in four categories: Continuous grinding tests using steel media; fracture tests on coal samples compacted at different pressure; SEM-Image analysis of feed and ground prod...

R. K. Mehta C. W. Schultz

1993-01-01

38

Retorting of coal, oil shale and tar sand by means of circulated fine-grained heat carriers as a preliminary stage in the production of synthetic crude oil  

Microsoft Academic Search

Numerous processes are available for the production of crude oil from coal, oil shale or tar sand. A process sequence which is suitable for all 3 starting materials includes a retorting step to produce oils, which are subsequently hydrogenated. An efficient modern retorting process is described, which has been commercially utilized for the flash carbonization of coal and has been

Rammler

1970-01-01

39

Soil porosity characteristics and water movement under zero tillage in silty soils in Argentinian Pampas  

Microsoft Academic Search

The objective of this study was to identify pore characteristics (quantity, distribution, stability and orientation of pores) that condition water dynamics under continuous zero tillage (ZT) on silty soils of the Argentinian Rolling Pampas. Soil properties were analyzed under continuous chisel plough (CP) and ZT treatments from three trials with different duration and crop sequence. The following soil properties of

M. C. Sasal; A. E. Andriulo; M. A. Taboada

2006-01-01

40

Benthic Bacterial Production and Protozoan Predation in a Silty Freshwater Environment  

Microsoft Academic Search

The interrelation of heterotrophic bacteria with bacterivorous protists has been widely studied in pelagic environments, but data on benthic habitats, especially in freshwater systems, are still scarce. We present a seasonal study focusing on bacterivory by heterotrophic nanoflagellates (HNF) and ciliates in the silty sediment of a temperate macrophyte-dominated oxbow lake. From January 2001 to February 2002 we monitored the

C. Wieltschnig; U. R. Fischer; A. K. T. Kirschner; B. Velimirov

2003-01-01

41

Mystery Sand  

NSDL National Science Digital Library

In this activity, learners play with surprising sand that doesnât get wet! Learners explore how water behaves differently when it comes in contact with "magic sand" and regular sand. Learners learn about the hydrophobic properties of "magic sand." Use this activity to talk about how many materials behave differently at the nanoscale.

Sciencenter

2012-01-01

42

Sand Drains.  

National Technical Information Service (NTIS)

Explains the sand drain method of consolidating swampy areas for the construction of highways. Uses animation and scenes of an actual project to show preparation of the site, driving the sand drains, placing the control devices and overload, final prepara...

1994-01-01

43

The Shear Strength Behavior of a Silty Soil in the Residual Zone of Unsaturation  

Microsoft Academic Search

The shear strength behavior of an unsaturated silty soil over the entire suction range was studied in this paper. In addition, the shear strength behavior was also studied following the drying and wetting path in the high suction range (i.e. 2,000 to 30,000 kPa). The results of the study show that the maximum shear strength value occurs approximately at the

T. Nishimura; H. Toyota; Sai K. Vanapalli; Won Taek Oh

44

Discovering Sand and Sand Paintings  

NSDL National Science Digital Library

This activity blends social studies and art with math and science. First, students will explore the visible characteristics of sand, and then they will make Navajo-style sand paintings with paper, glue, and colored sand. In the process, they will hone the

Eichinger, John

2009-05-30

45

Comparison of transport in lysimeters with undisturbed loamy sand and silty soil using non invasive imaging with electrical resistivity tomography  

NASA Astrophysics Data System (ADS)

The transport of chemicals through soil is subject to the 3-D structure of the soil hydraulic properties (e.g. unsaturated hydraulic conductivity function) and state variables (e.g. water content). Although this is known for decades, it is still difficult to quantitatively predict solute transport especially when preferential flow or fingering occurs. One reason for this is the shortcoming of 3-D data on both the solute transport process itself and its determining parameters. Lysimeters provide excellent means to control the boundary conditions and are accessible from all sides. Filled with undisturbed soil and equipped with geophysical imaging devices they provide a valuable tool to visualize and better understand solute transport in natural soils. In our study we conducted solute tracer step experiments on two distinct undisturbed unsaturated field soils (gleyic Cambisol and orthic Luvisol). The boundary conditions were set to constant irrigation (1.5 cm/day) at the top and a constant suction at the bottom. Tracer breakthrough was monitored using 3-D Electrical Resistivity Tomography (ERT) and Time-Domain Reflectometry (TDR). We used the effluent tracer breakthrough and TDR measured breakthrough as a ground truth for the ERT data. From these data, apparent convection-dispersion transport parameters were derived. We found considerably different transport velocities and dispersivities for the two soils. In the orthic Luvisol, distinct preferential transport paths were visualized and followed in time. In the gleyic Cambisol we observed minor heterogeneities in the transport front which were aligned to the plowing direction. The study demonstrates the usefulness of ERT to characterize and compare the 3-D spatio-temporal evolution of solute fronts. The results are beneficial to investigate relationships between soil structure and the transport process and to explain the scale dependency of the transport processes from the spatial structure of the process at a smaller scale.

Garre, S.; Köstel, J.; Vanderborght, J.; Javaux, M.

2009-04-01

46

Elevated gas hydrate saturation within silt and silty clay sediments in the Shenhu area, South China Sea  

NASA Astrophysics Data System (ADS)

Gas hydrate saturations were estimated using five different methods in silt and silty clay foraminiferous sediments from drill hole SH2 in the South China Sea. Gas hydrate saturations derived from observed pore water chloride values in core samples range from 10 to 45% of the pore space at 190-221 m below seafloor (mbsf). Gas hydrate saturations estimated from resistivity (Rt) using wireline logging results are similar and range from 10 to 40.5% in the pore space. Gas hydrate saturations were also estimated by P wave velocity obtained during wireline logging by using a simplified three-phase equation (STPE) and effective medium theory (EMT) models. Gas hydrate saturations obtained from the STPE velocity model (41.0% maximum) are slightly higher than those calculated with the EMT velocity model (38.5% maximum). Methane analysis from a 69 cm long depressurized core from the hydrate-bearing sediment zone indicates that gas hydrate saturation is about 27.08% of the pore space at 197.5 mbsf. Results from the five methods show similar values and nearly identical trends in gas hydrate saturations above the base of the gas hydrate stability zone at depths of 190 to 221 mbsf. Gas hydrate occurs within units of clayey slit and silt containing abundant calcareous nannofossils and foraminifer, which increase the porosities of the fine-grained sediments and provide space for enhanced gas hydrate formation. In addition, gas chimneys, faults, and fractures identified from three-dimensional (3-D) and high-resolution two-dimensional (2-D) seismic data provide pathways for fluids migrating into the gas hydrate stability zone which transport methane for the formation of gas hydrate. Sedimentation and local canyon migration may contribute to higher gas hydrate saturations near the base of the stability zone.

Wang, Xiujuan; Hutchinson, Deborah R.; Wu, Shiguo; Yang, Shengxiong; Guo, Yiqun

2011-05-01

47

Elevated gas hydrate saturation within silt and silty clay sediments in the Shenhu area, South China Sea  

USGS Publications Warehouse

Gas hydrate saturations were estimated using five different methods in silt and silty clay foraminiferous sediments from drill hole SH2 in the South China Sea. Gas hydrate saturations derived from observed pore water chloride values in core samples range from 10 to 45% of the pore space at 190-221 m below seafloor (mbsf). Gas hydrate saturations estimated from resistivity (Rt) using wireline logging results are similar and range from 10 to 40.5% in the pore space. Gas hydrate saturations were also estimated by P wave velocity obtained during wireline logging by using a simplified three-phase equation (STPE) and effective medium theory (EMT) models. Gas hydrate saturations obtained from the STPE velocity model (41.0% maximum) are slightly higher than those calculated with the EMT velocity model (38.5% maximum). Methane analysis from a 69 cm long depressurized core from the hydrate-bearing sediment zone indicates that gas hydrate saturation is about 27.08% of the pore space at 197.5 mbsf. Results from the five methods show similar values and nearly identical trends in gas hydrate saturations above the base of the gas hydrate stability zone at depths of 190 to 221 mbsf. Gas hydrate occurs within units of clayey slit and silt containing abundant calcareous nannofossils and foraminifer, which increase the porosities of the fine-grained sediments and provide space for enhanced gas hydrate formation. In addition, gas chimneys, faults, and fractures identified from three-dimensional (3-D) and high-resolution two-dimensional (2-D) seismic data provide pathways for fluids migrating into the gas hydrate stability zone which transport methane for the formation of gas hydrate. Sedimentation and local canyon migration may contribute to higher gas hydrate saturations near the base of the stability zone. Copyright 2011 by the American Geophysical Union.

Wang, X.; Hutchinson, D. R.; Wu, S.; Yang, S.; Guo, Y.

2011-01-01

48

Aging of Athabasca oil sand  

SciTech Connect

Samples of Athabasca oil sand collected by mining are frequently stored for long periods to ensure that research projects have available oil sand of consistent properties. This strategy is not entirely satisfactory because oil sands age after even limited exposure to oxygen. The results of a three-year aging study carried out at the Alberta Research Council are presented in this paper. During aging, the level of water soluble salts in the oil sand increased and hot water processing characteristics deteriorated. Through the DLVO and Ionizable Surface Group theories, it is demonstrated that the increase in soluble salts was sufficient to cause the fine solids particles to coagulate in the conditioning stage of the hot water process which results in poorer processibility characteristics. Based on this scenario, relative rates of aging for different grades of oil sand are estimated.

Wallace, D.; Henry, D.; Takamura, K.

1988-06-01

49

Tar sands  

Microsoft Academic Search

The four largest oil sand deposits contain over 90% of the world's known heavy oil. The total heavy oil and bitumen in place, estimated at nearly 6 trillion barrels is almost entirely concentrated in western Canada, principally Alberta, and eastern Venezuela. The known tar sand resource in the United States consists of about 550 occurrences located in 22 states. The

Wennekers; J. H. N

1981-01-01

50

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

51

Sands-on Learning.  

ERIC Educational Resources Information Center

Provides information for the development of a lesson which teaches students about sand, discusses facts about sands, sand studies, life in the sands, and sand activities. Includes diagrams showing the range in sand grain shape, formation of sand ripples, and sand samples from around the world. (RT)

Vandervoort, Frances S.

1989-01-01

52

Electroosmotic flow and the validity of the classical Darcy equation in silty shales  

NASA Astrophysics Data System (ADS)

Electroosmotic flow represents the flow of pore water through a porous medium submitted to an electrical field or an electrical current density. A model is developed to describe the coupled electric/hydraulic flow problem in silty shales. The strength of electroosmotic flow is modeled here as a function of porosity, grain shape, pH, and ionic strength of the pore water. In the case of forced flow under a pore fluid pressure gradient, electroosmosis reduces the filtration velocity. This effect can be modeled by introducing an effective or apparent permeability into the classical form of the Darcy equation. This apparent permeability can be much smaller than the intrinsic permeability and becomes very sensitive to the salinity of the pore water.

Revil, A.; Pessel, M.

2002-05-01

53

Bromide transport in a sandy and a silty soil - a comparative lysimeter study  

NASA Astrophysics Data System (ADS)

The aim of this study was a comparison of bromide leaching through a silty and a sandy soil and the characterization of systematic differences in solute transport in these undisturbed soils of differing texture. The amount of seepage water and bromide concentrations in the water were measured in 5 lysimeters for each soil type for a period of 460 days. Additionally, meteorological data were measured next to the lysimeter station for this period. The water transport regime of the lysimeters was simulated by means of a numerical solution of the Richards equation using the software package HYDRUS 1D. The observed bromide transport was simulated by steady-state approximation, applying the simulation tool CXTFIT, which is implemented in the software package STANMOD, version 2.0. Analysis of the measured data showed that a correct reproduction of the water balance was possible, but required the adaptation of soil-dependent crop coefficients for the potential transpiration of Phacelia and Winter Rape. The mean bromide transport through the sandy soil could be approximately reproduced assuming a bromide uptake by plants. Observed double peaks of some of the individual breakthrough curves, however, indicated that the actual transport regime in the lysimeters was subject to local heterogeneity which cannot be covered by the effective one-dimensional transport model. Bromide transport through the silty soil showed an unexplained mass deficit of nearly 90 % of the applied bromide and the detection of a mean distinct bromide peak in seepage water after percolation of only 0.5 pore volumes. It was not possible to simulate this behaviour with an effective 1D equilibrium or nonequilibrium convection-dispersion model.

Schober, L.; Iden, S. C.; Durner, W.

2009-04-01

54

Tar sands  

SciTech Connect

The four largest oil sand deposits contain over 90% of the world's known heavy oil. The total heavy oil and bitumen in place, estimated at nearly 6 trillion barrels is almost entirely concentrated in western Canada, principally Alberta, and eastern Venezuela. The known tar sand resource in the United States consists of about 550 occurrences located in 22 states. The total oil in place in 39 of these occurrences is estimated to be between 23.7 billion and 32.7 billion barrels. At least 90% of this resource is located in Utah. Other significant deposits are in Texas, New Mexico, California, and Kentucky. Bituminous sand deposits and petroleum-impregnated rocks are found in Malagasy, Albania, Rumania, the USSR, and Trinidad. 4 figures, 2 tables. (DP)

Wennekers, J.H.N.

1981-10-01

55

Association of the Fungicide Propiconazole with Size Fractionated Material from a Silty Clay Soil – S.E. Norway  

Microsoft Academic Search

Eroded soil material may be an important transporting agent for pesticides that are strongly sorbed to soil. The abilityof the fungicide propiconazole to interact with colloidal andparticulate materials has been studied by means of sorptionand desorption experiments. Size separation of silty clay soilfrom Mørdre, Norway and subsequent characterization showedthat different size fractions of soil possessed different physical and chemical properties

G. Riise; H. Madsen; T. Krogstad; M. Nandrup Pettersen

2001-01-01

56

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

57

Sand Babies  

NSDL National Science Digital Library

In this math lesson, learners explore and investigate measurement using standard and non-standard units. First, learners round their birth weight to the nearest pound and construct a bar graph displaying the weights of the entire group. Next, learners measure and place enough sand into a plastic bag to equal their birth weight. With construction paper, crayons and markers, they draw a head, arms, and legs and turn the bags into sand babies. At centers, learners also investigate other types of measurements using non-standard plastic links to measure parts of their body and square tiles to measure the area of a footprint.

Pbs

2012-01-01

58

Infiltration capacity and macroporosity of a silty-loamy soil under different tillage systems  

NASA Astrophysics Data System (ADS)

For soils under both agricultural and forest use, management and tillage practice have significant influence on different hydraulic properties. Under agricultural land use, the properties of the macropore system are, amongst others, a function of the applied management and tillage system (i.e. conventional vs. conservation tillage). Macropores are crucial to rapid infiltration of surface water and aeration of the soil. Low macroporosity will give rise to higher surface flow rates especially on sloping areas, thus enhancing the risk for higher erosion. Investigations were carried out near the town of Adenstedt (52^o00', 9^o56'), app. 50 km S of Hannover in Lower Saxony. The predominant soil in the study area is an eroded orthic Luvisol from glacial deposits with a predominant silty-loamy texture. The experimental site with two crop rotations has been run with two different tillage systems (e.g. conventional and conservative tillage) since 1990. In this study, the minimum radius of a macropore is set to r = 0.5 cm. Dye tracer experiments were performed with methylene blue that was sprayed on a confined irrigation plot. Staining patterns were recorded two hours later at defined depth increments and results of stained and unstained areas were manually digitized and processed with an appropriate GIS-software. Tension infiltrometer experiments were performed simultaneously with the dye tracer experiments using a tension infiltrometer (hood infiltrometer) at different hydraulic supply potentials and soils depths. Dye tracer experiments with methylene blue indicate a penetration depth of 120 cm on the reduced tilled plot as compared to the conventionally tilled plot (60 cm). Both tillage systems exhibit the highest density of macropores in the topsoil, ranging between 100 and 1.000 macropores per square meter. The conventionally tilled plot exhibits a higher number of macropores in the upper 20 cm than the reduced tilled plot while at greater soil depth, this holds true for the reduced tiled plot. Macroporosity derived from tension infiltrometer experiments yield results about one order of magnitude lower than those obtained by visual inventarization. The results indicate a greater continuity of vertically oriented macropores for soils with reduced tillage systems. Thus, in the context of a more effective prevention of flooding events in watersheds, tillage practices with reduced soil disturbance offer a means to decrease surface runoff by enhancing vertical drainage in agricultural areas with silty soils. However, the effect of this local-scale soil hydraulic property on the hydrological behavior on the scale of whole watersheds on the mesoscale (100--500 km^2) needs yet to be tested by simulations with physically based hydrological models.

Wahl, N. A.; Buczko, U.; Bens, O.; Hüttl, R. F.

2003-04-01

59

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

60

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  

NASA Astrophysics Data System (ADS)

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.

2007-12-01

61

Beach Sand  

NSDL National Science Digital Library

The purpose of this assessment probe is to elicit students' ideas about weathering, erosion, deposition, and landforms. It is designed to determine if students recognize that sand on a beach may have come from distant mountains and landforms as a result of the weathering of rock, subsequent erosion, and deposition.

Eberle, Francis; Farrin, Lynn; Keeley, Page

2005-01-01

62

Sands at Gusev Crater, Mars  

NASA Astrophysics Data System (ADS)

environments, and the energy associated with the transport and deposition of sand 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 sand 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 sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand 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 sands 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).

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.

2014-05-01

63

Lithostratigraphic analysis of sand and silt facies from NGHP 01 gas hydrate accumulations in the Krishna-Godavari Basin  

NASA Astrophysics Data System (ADS)

In 2006, an international effort led by the Indian National Gas Hydrate Program (NGHP) and the U.S. Geological Survey conducted the first large-scale exploration of gas hydrate accumulations. Seven sites were drilled within the Krishna-Godavari (KG) basin, a large syn-tectonic rift basin off the eastern shore of India, with the deepest hole penetrating ~300 mbsf. The sedimentary section in the KG basin includes up to 7 kilometers of Late Carboniferous to Holocene sediments from which commercial oil and natural gas production has been established. Detailed lithologic descriptions and physical properties measurements obtained from cores were combined with electrical log data to characterize the sedimentology and stratigraphy at each site. Our analyses indicate that sediments within the Gas Hydrate stability zone (GHSZ) in the KG basin record a Quaternary (<2MYA) history of deposition dominated by dark grey to black colored nannofossil bearing to rich clay and silty clay sourced from the nearby Krishna and Godavari Rivers. Relatively minor amounts of silt to fine sand beds and lamina (1-5 cm thick) were also observed as well as visible terrestrial organic material. The most pervasive mode of gas hydrate occurrence observed during NGHP-01 in the KG basin sites were disseminated hydrates in low-permeability silt-clay facies. Secondary gas hydrate accumulations were recovered in fracture fill, nodular and lens-like occurrences, or as pore-filling cement in the more permeable sand-silt beds and lamina. Thin sand beds and lamina were recovered at 6 of the 7 sites in the KG basin. ~330 sand beds were reported for all 6 sites with a typical bed thickness of ~3 cm. Net sand to gross sediment ratios ranged from 0.026 to 0.405. No major sand beds (>1 m thick) were recovered at any of the sites. Underlying the GHSZ in the KG basin are Pliocene and Pleistocene age sediments deposited during low-stand conditions. However, rising sea-level from the late Pleistocene to the present resulted in a gradual decrease in the volume of coarse grained material transported across the shelf, and slope related deposition during the Holocene has largely been controlled by episodic failure of shelf-edge deltaic deposits via turbidity flows in slope channels. At two KG sites, significantly greater net sand to gross sediment ratios were observed, perhaps indicating a closer proximity of those sites to turbidite channel-levee systems. While the channels may contain sand facies, given the slope dominant location of the NGHP well locations, it is likely that transported sand bypassed the well sites and was deposited in base-of-slope fans in deeper water to the east. Therefore, exploration for gas hydrate-bearing sands in the KG region should focus on the identification and location of the slope levee sand deposits or toe of slope sand rich fans within the GHSZ. gas/FutureSupply/MethaneHydrates/projects/DOEProjects/NETL-

Rose, K. K.; Boswell, R. M.; Johnson, J.; Nghp 01, S.

2008-12-01

64

Influence of crop residues on trifluralin mineralization in a silty clay loam soil.  

PubMed

Trifluralin is typically applied onto crop residues (trash, stubble) at the soil surface, or onto the bare soil surface after the incorporation of crop residues into the soil. The objective of this study was to quantify the effect of the type and amount of crop residues in soil on trifluralin mineralization in a Wellwood silty clay loam soil. Leaves and stubble of Potato (Solanum tuberosum) (P); Canola (Brassica napus) (C), Wheat (Triticum aestivum) (W), Oats (Avena sativa), (O), and Alfalfa (Medicago sativa) (A) were added to soil microcosms at rates of 2%, 4%, 8% and 16% of the total soil weight (25 g). The type and amount of crop residues in soil had little influence on the trifluralin first-order mineralization rate constant, which ranged from 3.57E-03 day(-1) in soil with 16% A to 2.89E-02 day(-1) in soil with 8% W. The cumulative trifluralin mineralization at 113 days ranged from 1.15% in soil with 16% P to 3.21% in soil with 4% C, again demonstrating that the observed differences across the treatments are not of agronomic or environmental importance. PMID:17454379

Farenhorst, Annemieke

2007-01-01

65

Altitude of the top of the Sparta Sand and Memphis Sand in three areas of Arkansas  

USGS Publications Warehouse

The Sparta Sand and Memphis Sand form the second most productive aquifer in Arkansas. The Sparta Sand and Memphis Sand range in thick- ness from 0 to 900 feet, consisting of fine- to medium-grained sands interbedded with layers of silt, clay, shale, and minor amounts of lignite. Within the three areas of interest, the top surface of the Sparta Sand and Memphis Sand 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.

Pugh, Aaron L.; Westerfield, Paul W.; Gonthier, Gerard J.; Poynter, David T.

1998-01-01

66

Tar sands development  

Microsoft Academic Search

Tar sands (also known as oil sands and bituminous sands) are sand deposits which are impregnated with dense viscous petroleum. Ultimate world reserves of bitumen in tar sands are about equal to ultimate reserves of crude oil in the U.S. However, the only tar-sand deposit of present commercial importance is in the Athabasca area of Alberta, Canada. The pioneer venture

1973-01-01

67

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

68

Transport of fine sediment over a coarse, immobile riverbed  

USGS Publications Warehouse

Sediment transport in cobble-boulder rivers consists mostly of fine sediment moving over a coarse, immobile bed. Transport rate depends on several interrelated factors: boundary shear stress, the grain size and volume of fine sediment, and the configuration of fine sediment into interstitial deposits and bed forms. Existing models do not incorporate all of these factors. Approaches that partition stress face a daunting challenge because most of the boundary shear is exerted on immobile grains. We present an alternative approach that divides the bed into sand patches and interstitial deposits and is well constrained by two clear end-member cases: full sand cover and absence of sand. Entrainment from sand patches is a function of their aerial coverage. Entrainment from interstices among immobile grains is a function of sand elevation relative to the size of the immobile grains. The bed-sand coverage function is used to predict the ratio of the rate of entrainment from a partially covered bed to the rate of entrainment from a completely sand-covered bed, which is determined using a standard sand transport model. We implement the bed-sand coverage function in a morphodynamic routing model and test it against observations of sand bed elevation and suspended sand concentration for conditions of nonuniform fine sediment transport in a large flume with steady uniform flow over immobile hemispheres. The results suggest that this approach may provide a simple and robust method for predicting the transport and migration of fine sediment through rivers with coarse, immobile beds.

Grams, Paul E.; Wilcock, Peter R.

2014-01-01

69

A Solution to the Problem of Predicting the Suitability of Silty–clayey Materials for Cement-stabilization  

Microsoft Academic Search

Major geotechnical problems in construction involving silty–clayey soils are due to their low strength, durability and high\\u000a compressibility of soft soils, and the swell–shrink nature of the overconsolidated swelling soils. Confronted with these problems,\\u000a a suitable ground improvement technique is needed, for deep excavations in soft clays, for stability, durability and deformation\\u000a control. Cement-stabilization is one of the alternatives. An

Evangelos I. Stavridakis

2006-01-01

70

Sand dunes of Taklimakan deset obtained from satellite data  

NASA Astrophysics Data System (ADS)

Making use of shadows effects in the images of SPOT/HRV, JERS-1/OPS, ASTER/VNIR/SWIR/TIR, LANDSAT-7/ETM+ and TERRA/MODIS an attempt is made to derive some geometrical features of sand dunes at Taklimakan Desert in China. It is found that the prevailing orientation of the sand dunes well coincides with the prevailing strong winds. In the northeastern part of the desert the spacing between the well developed large sand dunes is from 1.5 to 3 kms. It is also found that the small sand dunes are superimposed on the large sand dunes and the average of the spacing between small sand dunes is approximately 200 meters. It is interesting to notice that one order of smaller scale transversal sand dunes exists in the perpendicular direction of large longitudinal sand dunes. The height of sand dunes estimated from LANDSAT-7 image is approximately 50 meters. On the other hand the small sand dunes of fine sand exist in the southwestern part of the desert and the spacing between small sand dunes is from 150 to 200 meters. The height of small sand dunes estimated from SPOT image is approximately 20 meters. As mentioned above, it is shown that the image data obtained from various satellites is fairly useful for clarifying sand dunes features in the desert.

Tsuchiya, K.; Oguro, Y.

71

Sand Diver  

NASA Astrophysics Data System (ADS)

A few years ago, I was preparing to teach a summer enrichment program for middle school students at the University of Wisconsin-Stout. With swimming on the minds of most kids during the summer, I thought buoyancy would be a fun topic to discuss. An interesting way to introduce this concept is by discussing the beer-drinking balloonist who, in a lawn chair, floated to 11,000 feet above Los Angeles in 1997. However, I needed a hands-on project and was not about to go purchase some lawn chairs to duplicate this experiment. A simple submersible called the ``Sand Diver'' was designed and is now used as a hands-on activity for my introductory physics course.

Scott, Alan J.

2005-01-01

72

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

73

Estimating Particle-Size Distribution from Sand, Silt, and Clay Content  

NASA Astrophysics Data System (ADS)

Particle-size distribution (PSD) is one of the soil properties which not only is used in estimation of soil water retention curve as well as unsaturated hydraulic conductivity, but also is applied in the most hydrological studies. Since the measurement of particle-size distribution, soil water retention curve and unsaturated hydraulic conductivity is time consuming and expensive especially in large scale hydrological investigations, in this study, a method was developed based upon the least squares optimization approach to estimate cumulative particle-size distribution from sand, silt and clay content. A revised form of van Genuchten retention model which has been previously applied to represent cumulative particle-size distribution was fitted to the measured three points of PSD, and its two unknown parameters such as N and Dg were determined. For this purpose, we used curve fitting toolbox of MATLAB software. Then estimated N and Dg values were applied to estimate cumulative particle mass for other particle radii in order to determine the whole shape of PSD. A total of 80 soil samples from the UNSODA database including 10 soil textures were selected to verify the presented method. We divided our database into three groups, (1) is coarse soil texture including sand, sandy loam and loamy sand (32 soil samples), (2) medium soil texture such as sandy clay loam, loam, silt loam (31 soil samples), and (3) fine soil texture including clay, sandy clay, silty clay and clay loam (17 soil samples). The RMSE value was calculated to evaluate the presented method. For groups 1, 2 and 3, the RMSE values were 0.071, 0.064, and 0.046, respectively. The linear regression between the estimated and measured cumulative particle mass showed that this method is capable for estimating PSD from three measured points. The line slope for groups 1, 2 and 3 were 0.93, 0.94 and 0.95, respectively, and correlation coefficient (R2) values were obtained greater than 0.96. For all 80 soil samples, the RMSE, R2 and line slope values were 0.062, 0.97 and 0.94 indicating the proposed method estimated PSD accurately. Acknowledgements The authors would like to acknowledge Dr. M.Th. van Genuchten for providing the UNSODA database used in this study.

Roostaee, Maryam; Ghanbarian-Alavijeh, Behzad; Liaghat, Abdolmajid

2010-05-01

74

Bottom-current-controlled sand deposits — a review of modern shallow- to deep-water environments  

NASA Astrophysics Data System (ADS)

Different examples of modern marine-sand accumulations generated or strongly influenced by the action of bottom currents, are here presented. They are drawn from a variety of tectonic and morphological settings and grouped into three water-depth zones: deep-water (>2000 m), mid-water (300-2000 m), and outer-shelf/upper-slope (50-300 m). Deposits in the first two of these depth zones are normal contourites, according to their original definition (Heezen and Hollister, 1971) being those sediments that have been transported and deposited by contour currents in deep-water environments. Those deposited at shallower depths, under the influence of surficial geostrophic currents combined with other hydrodynamic factors (shelf currents induced by wind, tide and waves, gyres, internal waves, etc.), are more properly referred to as outer-shelf/upper-slope bottom-current sands (or shallow-water bottom-current sands). We have elaborated a facies model for each bathymetric zone. Deep-water sandy contourites are relatively rare, thin- and very thin-bedded, highly bioturbated and mainly of bioclastic composition. They are interbedded with muddy contourites and pelagites or, in some areas, with turbidites. In the latter case, thin bottom-current-reworked, sandy tops of turbidites provide a different and distinct facies. Mid-water sandy contourites are more common, ranging up to a metre in thickness, and may form extensive sandy sheets in a variety of slope, bank and channel settings. They are mainly of mixed siliciclastic—bioclastic composition, typically bioturbated, and associated with muddy/silty contourites in coarsening-up/fining-up complete or truncated sequences. Shallow-water bottom-current sands occur in particular outer-shelf/upper-slope settings, where they may develop relatively thick (1-20 m), laterally extensive sheets covered by fields of sandwaves, megaripples and ribbons. Internal structures may be preserved along with much bioturbation. Their composition varies from mainly siliciclastic to bioclastic, and they may be interbedded with both inner-shelf facies and slope hemipelagites. The principal factors that control the deposition of sandy contourites and shallow-water bottom-current sands are the hydrodynamic regime of the basin, the availability of coarse-grained (sandy) sediments and the physiographic context of the area swept by the currents. The greater the depth, the finer and rarer the bottom-current or sandy contourite deposits. Global sea-level and climatic changes and the time involved in the depositional history play an ultimate role in the development of important sand accumulations of this sort by controlling the ocean-circulation pattern and its long-term persistence. From the present analysis, we conclude that mid-depth sandy contourites are the most commonly found in modern environments, and that shallow-water bottom-current sands constitute the most significant potential oil reservoirs to be found in the geological record.

Viana, A. R.; Faugères, J.-C.; Stow, D. A. V.

1998-01-01

75

Unit weight measurement of sands by impregnation.  

National Technical Information Service (NTIS)

This investigation is an application of innovative method which H. Schneider and et al. investigated to measure unit weight. Various kinds of sand were used, and the suitable agar (impregnating material) was selected at the point of viscosity. A fine need...

K. Higaki M. Tanaka C. Fretti P. Morabito

1989-01-01

76

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

77

Responses of Red-Osier Dogwood to Oil Sands Tailings Treated with Gypsum or Alum  

Microsoft Academic Search

or composite tailings (CT), are currently being inves- tigated. The application of composite or consolidated tailings (CT) technol- In the CT process, the fines and sand fractions are ogy provides Alberta's oil sands industry with a means of reducing treated with a coagulant aid to produce a nonsegregating the volume of the fines fraction in extraction tailings and allows mixture

E. Redfield; C. Croser; J. J. Zwiazek; M. D. MacKinnon; C. Qualizza

2003-01-01

78

The effects of oil sands wetlands on wood frogs (Rana sylvatica)  

Microsoft Academic Search

Extraction of crude oil from oil sand produces solid (sand) and liquid (water with suspended fine particles) tailings materials, called oil sands process-affected materials (OSPM). These waste materials are stored on the mine site due to a “zero discharge” policy and must be reclaimed when operations end. The liquid tailings materials are known to contain naphthenic acids and polycyclic aromatic

Blair D. Hersikorn; Jan J. C. Ciborowski; Judit E. G. Smits

2010-01-01

79

Critical state of sand matrix soils.  

PubMed

The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand 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 sand 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 sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

2014-01-01

80

Critical State of Sand Matrix Soils  

PubMed Central

The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand 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 sand 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 sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

2014-01-01

81

Aeolian sand transport: a wind tunnel model  

NASA Astrophysics Data System (ADS)

Wind sand transport is an important geological process on earth and some other planets. Formulating the wind sand transport model has been of continuing significance. Majority of the existing models relate sand transport rate to the wind shear velocity based on dynamic analysis. However, the wind shear velocity readapted to blown sand is difficult to determine from the measured wind profiles when sand movement occurs, especially at high wind velocity. Moreover, the effect of grain size on sand transport is open to argument. Detailed wind tunnel tests were carried out with respect to the threshold velocity, threshold shear velocity, and transport rate of differently sized, loose dry sand at different wind velocities to reformulate the transport model. The results suggest that the relationship between threshold shear velocity and grain size basically follow the Bagnold-type equation for the grain size d>0.1 mm. However, the threshold coefficient A in the equation is not constant as suggested by Bagnold, but decreases with the particle Reynolds number. The threshold velocity at the centerline height of the wind tunnel proved to be directly proportional to the square root of grain diameter. Attempts have been made to relate sand transport rate to both the wind velocity and shear velocity readapted to the blown sand movement. The reformulated transport model for loose dry sand follows the modified O'Brien-Rindlaub-type equation: Q= f1( d)(1- Ru) 2( ?/ g) V3, or the modified Bagnold-type equation: Q= f2( d)(1- Rt) 0.25( ?/ g) U*3. Where Q is the sand transport rate, the sand flux per unit time and per unit width, in kg m -1 s -1; ? is the air density, 1.25 kg m -3; g is the acceleration due to gravity, 9.81 m s -2; Ru= Vt/ V; Rt= U*t/ U*; V is the wind velocity at the centerline of the wind tunnel, in m s -1; Vt is the threshold velocity measured at the same height as V, in m s -1; U* is the shear velocity with saltating flux, in m s -1; U*t is threshold shear velocity, in m s -1; f1( d)=1/(475.24+93.62 d/ D); f2( d)=1.41+4.98exp(-0.5(ln( d/1.55 D)/0.57) 2); d is the grain diameter, in mm; and D is the reference grain diameter, equals 0.25 mm. The Bagnold's equation that asserts for a given wind drag the rate of movement of a fine sand is less than that of a coarse sand is not supported by the reformulated models.

Dong, Zhibao; Liu, Xiaoping; Wang, Hongtao; Wang, Xunming

2003-09-01

82

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

83

Sand Analysis Lab Activity  

NSDL National Science Digital Library

An inclass introductory level activity for science and nonscience majors that explores the properties of sand in order to identify depositional environments. Sand Analysis Lab (Microsoft Word 71kB May18 12)

Weiss, Tarin

84

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.

85

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

86

Asbestos in play sand  

Microsoft Academic Search

A letter in the New England Journal of Medicine (Oct. 2 issue) stated that a carbonate sand marketed in New Jersey was contaminated with 2 to 4 percent tremolite asbestos. The authors were called on by one of the federal agencies to repeat the analysis of this sand, specifically for its asbestos content. The sand was pulverized and immersed in

A. M. Langer; R. P. Nolan

1987-01-01

87

Exploring Products: Nano Sand  

NSDL National Science Digital Library

In this activity, learners explore how water behaves differently when it comes in contact with "nano sand" and regular sand. Learners learn about the hydrophobic properties of "nano sand." Use this activity to talk about how many materials behave differently at the nanoscale.

Network, Nanoscale I.; Sciencenter

2010-01-01

88

Qualifying tight sands  

Microsoft Academic Search

Qualifying parts of Kentucky's Big Sand gas field for tight sands designation will not be the only benefit to come out of the work now being done by the Kentucky Oil and Gas Association's Tight Sands Committee. The committee plans to evaluate all oil and gas producing formations in E. Kentucky for possible designation. Committee members are gathering detailed information

Harbert

1981-01-01

89

Books of sand  

Microsoft Academic Search

Books of Sand are interactive installations that relate the movement of hands in the sand to hypertexts containing Jorge Luis Borges texts taken from the Web. It consists of one or more glass buckets full of sand that when touching it with the hands, projected codes retrieved from the Web arise interacting with the movement of the hands.A video camera

Sardón Mariano

2006-01-01

90

Coagulation of bitumen with fine silica in model systems  

Microsoft Academic Search

A prerequisite for recovering bitumen from oil sands is to liberate the bitumen phase from sand (clay) surfaces and to avoid bitumen\\/sand aggregation, both being related to bitumen\\/solids interactions. Coagulation of bitumen with fine silica (?5?m) was investigated in this study as a function of pH and calcium ion concentrations. To explore the effect of surfactant present in bitumen on

Z. A. Zhou; Zhenghe Xu; Jacob H. Masliyah; Jan Czarnecki

1999-01-01

91

Recycling of PET bottles as fine aggregate in concrete  

Microsoft Academic Search

An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water\\/cement ratio were manufactured. Rheological characterization on fresh concrete

Mariaenrica Frigione; Mariaenrica

2010-01-01

92

Particle-Size Fractionation of Eolian Sand Along the Sinai-Negev Erg of Egypt and Israel  

NASA Astrophysics Data System (ADS)

This study examines changes in the eolian sand fractions along the west - east transport path of the northern Sinai Peninsula - northwestern (NW) Negev erg of Egypt and Israel. This erg is composed of active linear (seif) dunes in northern Sinai (its western part), and stabilized vegetated linear dunes (VLDs) in the NW Negev dunefield (its eastern part). Sand samples were analyzed for sand grain morphology, particle-size distribution and optically stimulated luminescence ages. Linear seif dunes differ from VLDs in their vegetation cover, linearity, and dynamics. Although both are continuous landforms with similar orientations and sand-grain roundness values, the linear dunes of Sinai are coarser-grained than the Negev VLDs. The VLDs have a significantly higher proportion of very fine sand (125-50 ?m) content and a varying but lower sand fining ratio defined as the ratio of fine sand percentage to very fine sand percentage. From these observations we infer that fractionation of sand occurred along the studied eolian transport path. Very fine sands are suggested to have been winnowed by saltation and low suspension from source deposits and sand sheets. We suggest that the very fine sand fraction of Nile Delta and Sinai sands has been transported downwind since the late middle Pleistocene. In the late Pleistocene, linear dunes reached the NW Negev due to last-glacial period windiness of intensities unprecedented today and probably larger sediment supply. Generally decreasing wind velocities and increasing precipitation along the west - east dune transport path enhanced vegetative cover in the northern Negev and enabled deposition of the very fine sand component that was also transported by low suspension. We hypothesize that these very find sands also probably compose a partial fraction of the northern Negev loess deposits, still farther downwind. Our results suggest that particle-size distribution can elucidate much about erg and dunefield history over timescales of a glacial-interglacial cycle.

Roskin, J.; Katra, I.; Blumberg, D. G.

2012-12-01

93

Fine Arts.  

ERIC Educational Resources Information Center

Discusses the use of fine arts as sources to enrich the study of history. Suggests that such works will serve as barometers of change, examples of cross-cultural influences, and political messages. Includes suggestions of works and artists from different historic periods. (DK)

Danzer, Gerald A.; Newman, Mark

1992-01-01

94

Observations of Sand Transport Processes Over Sorted Bedforms  

NASA Astrophysics Data System (ADS)

High resolution sonar surveys in the past decade have revealed that complex sorted bedforms (rippled scour depressions, RSDs) are ubiquitous features on many sandy inner shelves. These features consist of alternating bands of coarse and fine sand with along-shore scales of 10 to 1000 m and across-shore scales of 100 to 5000 m. Modeling approaches for these features have ranged from rules-based approaches to sediment transport physics based approaches. However, the sediment transport processes over fine and coarse sand with combined weakly non-linear waves and mean current forcing are poorly understood. Specifically, the relative roles of bedload and suspended load forced by non-linear waves and mean currents over large ripples in coarse sand and smaller ripples, or low-relief bed conditions in fine sand are not well understood. For instance, tripod mounted rotary sonar observations have generally shown onshore ripple migration forced by non-linear wave velocities to be the dominant transport process in coarse sand. However, larger-scale sonar and grab sample surveys have shown along-shore grain size variability that is presumably forced by along-shore mean currents. Over the past three years, observations were conducted at the Martha's Vineyard Coastal Observatory RSD field in attempts to quantify the relative roles of these processes. A quadpod, with a rotary sidescan sonar and a 2-axis pencil beam sonar to measure ripple morphology, was deployed in both coarse and fine sand in successive winter seasons. The quadpod also had a 3-axis bistatic pulse coherent acoustic Doppler profiling system that is capable of measuring near-bed (within 30 cm of the seafloor) suspended and bedload transport. Bedload was estimated using spectral processing on the bed and bedload backscatter, thus the high intensity returns from the stationary bed could be separated from returns from the moving bedload in the frequency domain. Preliminary analysis of the observations revealed that in fine sand the transport is dominated by suspended load forced by wave-resuspension and mean current transport. The observations in fine sand contained many storms of varying energy thus are fairly robust. The observations in coarse sand only had 4 hours of data during moderate-energy active conditions, due to a equipment failure, thus additional data and analysis is required to determine the amount of along-shore transport and the relevant forcing processes in coarse sand during more energetic events. From the available data in coarse sand, onshore bedload and near-bed suspended load transport (within 1 cm of the seafloor) forced by non-linear waves dominated the flux, consistent with prior observations of bedload flux estimated from ripple migration.

Traykovski, P.

2005-05-01

95

Cyclic stress-strain and liquefaction characteristics of sands  

SciTech Connect

Liquefaction of saturated sand and silty sand deposits has been recognized as a major cause of damage during earthquakes. However, in spite of many research studies during the past two decades, there are still conflicting opinions on critical aspects of the phenomenon of soil liquefaction, including the definition of the term liquefaction. For these reasons, a research program on the behavior of cohesionless soils under cyclic loading was initiated at Purdue University. An important effort was devoted to delineate and understand the physical factors controlling the response of cohesionless soils to cyclic loading and consequently, the factors involved in the different phenomena that have been described with the term liquefaction such as steady-state flow, a condition of zero effective stress, or cumulative residual strains due to cyclic loading. A new hybrid resonant column/torsional shear apparatus was designed and built as a part of this research program. The new apparatus permits the determination of dynamic soil properties on a single solid or hollow cylinder specimen over the entire range of shear strain amplitudes of engineering interest, i.e. from 10/sup -5/ to 10%. Torsional shear test were performed with the new apparatus on reconstituted specimens of Ottawa 20-30 sand. Results are presented briefly.

Alarcon-Guzman, A.

1986-01-01

96

Discrimination of active and inactive sand from remote sensing - Kelso dunes, Mojave Desert, California  

NASA Technical Reports Server (NTRS)

Landsat TM images, field data, and laboratoray reflectance spectra were examined for the Kelso dunes, Mojave Desert, California to assess the use of visible and near-infrared (VNIR) remote sensing data to discriminate aeolian sand populations on the basis of spectral brightness. Results show that areas of inactive sand have a larger percentage of dark, fine-grained materials compared to those composed of active sand, which contain less dark fines and a higher percentage of quartz sand-size grains. Both areas are spectrally distinct in the VNIR, suggesting that VNIR spectral data can be used to discriminate active and inactive sand populations in the Mojave Desert. Analysis of laboratory spectra was complicated by the presence of magnetite in the active sands, which decreases their laboratory reflectance values to those of inactive sands. For this application, comparison of TM and laboratory spectra suggests that less than 35 percent vegetation cover does not influence the TM spectra.

Paisley, Elizabeth C. I.; Lancaster, Nicholas; Gaddis, Lisa R.; Greeley, Ronald

1991-01-01

97

Organic carbon and ammonium nitrogen removal in a laboratory sand percolation filter.  

PubMed

The on-site treatment of wastewaters from single dwellings requires simple, low maintenance systems that reduce the chemical and biochemical oxygen demand (COD and BOD respectively), ammonium-nitrogen (NH4-N), orthophosphate (PO4-P), phosphorus (P), and microorganisms to acceptable concentrations. Sand filters have the potential to achieve these reductions. In this study, a sand tank model of a percolation trench and filter was constructed in the laboratory, loaded with wastewater, and monitored for a period of 293 days. The silty sand filter was seeded for 153 days with effluent from an aerobic biofilm treatment unit. The filter was then loaded with synthetic wastewater of domestic strength for 193 days, when the average organic and hydraulic loading rates on the percolation trench were 13.33 g BOD/m2 d and 75 L/m2 d respectively. Removal rates of 90% for total COD, 99.3% for BOD5, >99% for total NH4-N, 89% for total PO4-P, and 96% for total suspended solids (TSS) were recorded during the study. No excessive clogging of the sand filter was observed. During the study very good dispersion of the wastewater over the sand filter by the percolation trench was recorded. The sand filter was simple to construct and operate and achieved excellent results. PMID:15478928

Rodgers, M; Clifford, E; Mulqueen, J; Ballantyne, P

2004-01-01

98

Comparison of natural and manufactured fine aggregates in cement mortars  

Microsoft Academic Search

The performance of cement mortars using manufactured fine aggregates produced by cone crushing or impact crushing has been compared to that of mortars prepared from a natural sand control-sample. Samples from both crusher products have been additionally subjected to classification for partial removal of fines, being also used in preparing mortars. Particle shape analyses indicated that material produced by impact

J. P. Gonçalves; L. M. Tavares; R. D. Toledo Filho; E. M. R. Fairbairn; E. R. Cunha

2007-01-01

99

Kentucky tar sand project  

Microsoft Academic Search

Engineering details and pilot-plant results from a pioneering investigation based on a Kentucky tar-sand reserve are presented. The tar sand deposits of Kentucky are generally situated in the southeastern rim of the Illinois Basin along the southern boundary of the Western Coal Field region. In a recent study of US tar sand reserves, it was reported that over 3.4 billion

M. N. Kelley; H. D. II Jones; F. W. Lewis

1985-01-01

100

Sand Sea Wonders: Geology  

NSDL National Science Digital Library

This site describes the geology of The Great Sand Dunes National Monument and Preserve. Active links allow students to explore the geologic timeline, geologic cross section in animation, and the wind regime. A reversing dune is shown in animation and other dunes such as star, parabolic, barchan, and transverse are discussed. Another section illustrates sand recycling by seasonal streams. A sand deposits map shows topography, dunes watershed, old national monument boundary, roads, and surface water and a section called 'How Much Sand' quantifies the description. Artwork on this site includes both adult and 'Hands on the Land' student artwork while photography depicts dunes, landscape, animals, plants, and human history.

101

Sand filter clogging by septic tank effluent.  

PubMed

The aim of this study was to characterise conditions and factors affecting fine sand clogging by septic tank effluent on the basis of physical modelling. The physical model consisted of 12 sand columns dosed with sewage from one household (5 persons), preliminary treated in a septic tank. Hydraulic loadings of the sand filters were equal to 82 mm/d. The mean discharge from sand columns, measured as the effluent volume collected during 10 minutes, decreased significantly over the experiment period from 34 cm3/min in August 2000 to 20 cm3/min in August 2001 at the same temperature of about 20 degrees C. First the columns clogged almost completely after 480 days in December 2001, however six columns had remained unclogged till the end of the experiment (March 2002). The temperature had a significant impact on hydraulic conductivity. A vertical distribution of accumulated mass and biomass was investigated in partly clogged sand. Microscopic survey of the clogging layer showed a presence of live micro-organisms, residuals of dead micro-organisms, particularly pieces of small animal armour and many fibres. These particles accelerated the accumulation of solids in the upper clogging layer. The study indicated that temperature impact on the filter hydraulic conductivity was more significant for biological activity, than for sewage viscosity. PMID:14753531

Spycha?a, M; B?azejewski, R

2003-01-01

102

"Sand Boil" on Bay Bridge  

USGS Multimedia Gallery

"Sand boil" or sand 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 sand into a sand-water slurry (liquefaction). Vented sand contains-marine shell f...

2009-01-26

103

Submarine sand sampler  

Microsoft Academic Search

A subsurface sampler which obtains samples of sand from offshore deposits is described. A 27-foot tube within a tube is lowered to the ocean floor while suspended from flotation tanks. The sampler is free of suspension cables and thus is detached from boat motions. Surface sand is sucked up through the suction tube and pumped to a container on deck

Casciano

1980-01-01

104

Oil from tar sands  

Microsoft Academic Search

For many years, the tar sand deposits of the world have drawn a great deal of attention as possible sources of enormous quantities of crude oil. The total in-place reserves are estimated at over 900 billion bbl, 3 times the liquid petroleum reserves of the world. In the Western Hemisphere, the largest deposits of tar sands occur in Canada, Venezuela,

Farouq Ali

1968-01-01

105

Evaluation of metal mobility, plant availability and immobilization by chemical agents in a limed-silty soil.  

PubMed

Metal-contaminated soils in the vicinity of industrial sites become of ever-increasing concern. Diagnostic criteria and ecological technologies for soil remediation should be calibrated for various soil conditions; actually, our knowledge of calcareous soil is poor. Silty soils near smelters at Evin (Pas de Calais, France) have been contaminated by non-ferrous metal fallout and regularly limed using foams. Therefore, the mobility, bioavailability, and potential phytotoxicity of Cd, Pb and Zn, were investigated using single soil extractions (i.e. water, 0.1 n Ca(NO(3))(2), and EDTA pH 7), and vegetation experiments, in parallel with a biological test based on (iso)-enzymes in leaves and roots, before and following soil treatment with chemical agents, i.e. Thomas basic slags (TBS), hydrous manganese oxide (HMO), steel shots (ST) and beringite. No visible toxicity symptoms developed on the above-ground parts of ryegrass, tobacco and bean plants grown in potted soil under controlled environmental conditions. Cd, Zn and Pb uptake resulted in high concentrations in the above-ground plant parts, but the enzyme capacities in leaves and roots, and the peroxidase pattern indicated that these metal concentrations were not phytotoxic for beans as test plants. The addition of chemical agents to the soil did not increase biomass production, but treatment with either HMO, ST or beringite markedly decreased the mobility of Cd, Zn and Pb. These agents were proven to be effective in mitigating the Cd uptake by plants. HMO and ST decreased either Pb or Zn uptake by ryegrass. TBS was effective in lowering Pb uptake by the same species. Beringite decreased Cd uptake by beans. If fallout could be restricted, the metal content of food crops in this area should be lowered by soil treatment. However, the differences in Cd uptake between plant species were not suppressed, regardless of the type of agents applied to the soil. PMID:15091619

Mench, M; Vangronsveld, J; Didier, V; Clijsters, H

1994-01-01

106

Bonded-Sand/Loose-Sand Composite Mold.  

National Technical Information Service (NTIS)

The invention discusses a method of casting metal using evaporative pattern casting process patterns in combination with a bonded-sand form. The invention includes a dual-phase molding system that provides backup rigidity and physically restrains an EPC p...

J. S. Hansen P. C. Turner L. G. Higgins

1992-01-01

107

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

SciTech Connect

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 with the underlying Freeman Silt and the overlying Round Mountain Silt. In the type area, in Round Mountain oil field, the Olcese is 300-360 m thick. The Olcese is subdivided into three environmental facies. In the Knob Hill Quadrangle, the lower Olcese consists of (1) thinly bedded to blocky white tuffaceous silt and sand, or (2) planar cross-bedded fine to coarse-grained sand with pumice pebbles lining the bedding surfaces. Fossil mollusks and skate teeth indicate a shallow marine environment for the lower Olcese. Although the Olcese is predominantly a marine unit, the middle Olcese is nonmarine, with lenses of marine deposition. The middle Olcese is well exposed in the Knob Hill, Oil Center, and Rio Bravo Ranch Quadrangles, and is characterized by fine to coarse sand with occasional gravel lenses, strong cross-bedding, and a blue-gray color. The upper Olcese is a very fine to medium-grained, marine sand that fines upward into a sandy siltstone southward toward the Kern River. Foraminifera and mollusks from outcrops in the Rio Bravo Ranch Quadrangle indicate outer shelf to estuarine environments for the upper Olcese. The varying environments in the Olcese Sand reflect slight but frequent fluctuations in water depth and can be used to interpret the basin-margin history.

Olson, H.C.

1986-04-01

108

Basaltic island sand provenance  

SciTech Connect

The Hawaiian Islands are an ideal location to study basaltic sand provenance in that they are a series of progressively older basaltic shield volcanoes with arid to humid microclimates. Sixty-two sand samples were collected from beaches on the islands of Hawaii, Maui, Oahu and Kauai and petrographically analyzed. The major sand components are calcareous bioclasts, volcanic lithic fragments, and monomineralic grains of dense minerals and plagioclase. Proportions of these components vary from island to island, with bioclastic end members being more prevalent on older islands exhibiting well-developed fringing reef systems and volcanic end members more prevalent on younger, volcanically active islands. Climatic variations across the island of Hawaii are reflected in the percentage of weathered detritus, which is greater on the wetter, northern side of the island. The groundmass of glassy, basaltic lithics is predominantly black tachylite, with lesser brown sideromelane; microlitic and lathwork textures are more common than holohyaline vitric textures. Other common basaltic volcanic lithic fragments are holocrystalline aggregates of silt-sized pyroxene or olivine, opaque minerals and plagioclase. Sands derived from alkalic lavas are texturally and compositionally indistinguishable from sands derived from tholeiitic lavas. Although Hawaiian basaltic sands overlap in composition with magmatic arc-derived sands in terms of their relative QFL, QmPK and LmLvLs percentages, they are dissimilar in that they lack felsic components and are more enriched in lathwork volcanic lithic fragments, holocrystalline volcanic lithic fragments, and dense minerals.

Marsaglia, K.M. (Univ. of Texas, El Paso, TX (United States). Dept. of Geological Sciences)

1992-01-01

109

Vent of Sand Volcano  

USGS Multimedia Gallery

Vent of sand 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....

2009-01-26

110

The Flow of Sand.  

ERIC Educational Resources Information Center

Describes a simple demonstration of the flow of sand through an orifice at the bottom of a sandbox. Advocates the experiment's use with dimensional analysis for students in an introductory physics course. (WRM)

Yersel, Metin

2000-01-01

111

Qualifying tight sands  

SciTech Connect

Qualifying parts of Kentucky's Big Sand gas field for tight sands designation will not be the only benefit to come out of the work now being done by the Kentucky Oil and Gas Association's Tight Sands Committee. The committee plans to evaluate all oil and gas producing formations in E. Kentucky for possible designation. Committee members are gathering detailed information on locations of wells, porosity and permeability of producing formations, and other production data within certain counties as part of the work required by the Federal Energy Regulatory Commission to determine areas for tight sands designation. These data are being entered into the computer system at the Kentucky Geological Survey, and will eventually be used to produce computerized planimetric maps.

Harbert, T.

1981-11-01

112

Sand Wave Study.  

National Technical Information Service (NTIS)

This report will provide further information on the origins of depositional bed forms and their attendant flow regimes. It will focus on sand wave formation, size, and dynamics because the occurrence of these features can have far reaching implications on...

A. DeVisser

1997-01-01

113

Sand on the Move  

NSDL National Science Digital Library

This site, from the National Park Service (NPS) and United States Geological Institute (USGS), gives a brief description of how sand dunes form. It describes how dunes will develop over time by repeating the processes of erosion, transportation, and deposition.

114

Great Sand Dunes.  

National Technical Information Service (NTIS)

Shows the 700-foot high dunes in their endless cycle of building and decaying, and explains in lay terms the geologic reasons for the dunes. Primary audience: visitors to Great Sand Dunes National Monument.

1994-01-01

115

Magic Sand Movie  

NSDL National Science Digital Library

This document from the Midwest Regional Center for Nanotechnology Education (NANO-LINK) is intended to be used with the other materials in the "magic sand" series of classroom lessons, which are available here. This resource is a 4 minute video demonstrating the magic sand 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."

2013-07-03

116

Sand Grain Observations  

NSDL National Science Digital Library

In this activity (on page 1 of the PDF), learners will use a magnifier to carefully examine samples of sand from different locations. They record their observations regarding the different grain characteristics to formulate their own explanations of where the sand came from, why the grains are jagged or smooth, and how they may have been sorted. Relates to the linked video, DragonflyTV GPS: Earthquakes.

Twin Cities Public Television, Inc.

2006-01-01

117

Reservoir properties and ore structure of tight gas sands  

Microsoft Academic Search

Thin section and SEM observations indicate that tight gas sands may be grouped into four broad categories based on pore geometry. These consist of (1) primary interparticle porosity; (2) primary interparticle porosity filled with authigenic minerals; (3) primary porosity reduced to narrow cracks with secondary honeycombed grains; and (4) intercrystalline porosity within a fine grained, elongate matrix. Type 1 porosity

Soeder

1984-01-01

118

Interaction forces in bitumen extraction from oil sands.  

PubMed

Water-based extraction process (WBEP) has been successfully applied to bitumen recovery from Athabasca oil sand ore deposits in Alberta. In this process, two essential steps are involved. The bitumen first needs to be "liberated" from sand grains, followed by "aeration" with air bubbles. Bitumen "liberation" from the sand grains is controlled by the interaction between the bitumen and sand grains. Bitumen "aeration" is dependent, among other mechanical and hydrodynamic variables, on the hydrophobicity of the bitumen surface, which is controlled by water chemistry and interactions between bitumen and fine solids. In this paper, the interaction force measured with an atomic force microscope (AFM) between bitumen-bitumen, bitumen-silica, bitumen-clays and bitumen-fines is summarized. The measured interaction force barrier coupled with the contacted adhesion force allows us to predict the coagulative state of colloidal systems. Zeta potential distribution measurements, in terms of heterocoagulation, confirmed the prediction of the measured force profiles using AFM. The results show that solution pH and calcium addition can significantly affect the colloidal interactions of various components in oil sand extraction systems. The strong attachment of fines from a poor processing ore on bitumen is responsible for the corresponding low bitumen flotation recovery. The identification of the dominant non-contact forces by fitting with the classical DLVO or extended DLVO theory provides guidance for controlling the interaction behavior of the oil sand components through monitoring the factors that could affect the non-contact forces. The findings provide insights into megascale industrial operations of oil sand extraction. PMID:15925617

Liu, Jianjun; Xu, Zhenghe; Masliyah, Jacob

2005-07-15

119

New sand-control filter for thermal recovery wells  

SciTech Connect

A device was designed to solve a severe case of sand inflow into horizontal wells at the Athabasca Tar Sands pilot plant in Fort McMurray, Alta. The sand problem at this pilot resulted from a combination of three conditions: a fine-grained, cohesionless sand; the cyclic injection of steam; and the production of steam, water, and high-viscosity bitumen. A new type of filter, designed to overcome this problem, has application to the control of solids in wells drilled in a variety of formations producing liquids or gas. It was first designed and tested in the laboratory with a physical simulator; then it was fabricated and tested in vertical wells at the Athabasca pilot plant.

Toma, P.; Livesey, D.; Heldrick, T.

1988-05-01

120

Aging effects on oil-contaminated Kuwaiti sand  

SciTech Connect

Large quantities of oil-contaminated sands resulted from the destruction of oil wells and the formation of oil lakes in Kuwait at the end of the Gulf Wa/r. A laboratory testing program was carried out to determine the geotechnical properties of this material and the effect of aging on their properties. Tests included direct shear, triaxial, and consolidation tests on clean and contaminated sand at the same relative density. The influence of aging was examined by testing uncontaminated sand after aging for one, three, and six months in natural environmental conditions. The results indicated increased strength and stiffness due to aging and a reduction of the oil content due to evaporation of volatile compounds. The factors that influence the depth of oil penetration in compacted sand columns were also examined including the type of oil, relative density, and the amount of fines.

Al-Sanad, H.A.; Ismael, N.F. [Kuwait Univ., Safat (Kuwait). Dept. of Civil Engineering

1997-03-01

121

Near-shore sand thickness and stratigraphy mapping with a submerged GPR antenna system; southeast Lake Michigan  

SciTech Connect

Twenty-one shore perpendicular profiles, spaced at nominal 5 km intervals, have been surveyed with a bottom-sled mounted Ground Penetrating Radar (GPR) antenna system between Benton Harbor, MI, and Gary, IN. Either a commercial 500 MHz or a custom 145 MHz antenna were used. The bottom sled also carried an upward looking SONAR transducer to give concurrent water depth, and was towed from the beach out to water depths of 6 meters or more, usually ending about 500 meters from shore. Bedding structures and details are clearly visible on the GPR sections within the sand bars and sand blankets. Bottom morphology and the nature of the sand bodies change markedly from the NE to the SW limits of the survey area. At the NE profiles there are multiple, pronounced (or high amplitude) offshore bars, with the substrate (glacial clay, shale, or silty sand) exposed or nearly exposed between bars. Internal structure is generally foreset or cross bedding in the bars. Sand was thin or missing immediately to the Sw of several other jetty structures in addition to the one at St. Joseph. In general the sand bars became much less pronounced to the SW, and internal structures were dominated by parallel bedding and subtle angular unconformities. Near St. Joseph, the exposed substrate is almost certainly being eroded, even to water depths as great as 6 meters. Thus, the equilibrium bottom profile continues to deepen shoreward, causing the continued threat of bluff erosion in spite of annual beach nourishment efforts at this site.

Sauck, W.A.; Seng, D.L. (Western Michigan Univ., Kalamazoo, MI (United States))

1994-04-01

122

A sedimentation device to produce uniform sand packs  

NASA Astrophysics Data System (ADS)

In physical modelling using sand, the construction of a sand pack is one of the main experimental difficulties. Existing solutions are generally based either on delicate manipulations (pouring and scraping), or on motorized sedimentation devices, and the qualities of packs thus produced are known to affect experimental outcomes. However, uniformity, planarity, reproducibility and efficiency can be achieved with a simple sedimentation device without motors. A rectangular reservoir pierced with holes rests on a support plate pierced with wider holes. Sand flows when the reservoir is displaced so that its holes match those of the support plate. Sand jets are diffused by planar horizontal sieves, below which the sand sets into the experimental box. Tests on a 250 ?m median grain size sand show that the density is at its maximum value, reproducible, and uniform. The spatial variations are only of ± 0.4% of the mean density. Thickness of the sand layers shows spatial variations around ± 2% of the mean thickness, and 6% near the side walls. Very fine grains (90 ?m median grain size) produce less uniform and less planar packs because of their greater sensitivity to air currents caused by the sedimentation. According to direct shear tests the sand pack has a well defined static friction coefficient decreasing to a lower dynamic value after about 3 mm of slip with dilatancy. In contrast, poured sand packs, which are initially less dense, develop only the dynamic friction coefficient (no peak shear stress during slip), without dilatancy. Hole diameters, hole spacing, and the number and openings of the sieves are the parameters controlling the qualities of the sand pack for a given grain size distribution.

Maillot, Bertrand

2013-05-01

123

Kentucky tar sand project  

SciTech Connect

Engineering details and pilot-plant results from a pioneering investigation based on a Kentucky tar-sand reserve are presented. The tar sand deposits of Kentucky are generally situated in the southeastern rim of the Illinois Basin along the southern boundary of the Western Coal Field region. In a recent study of US tar sand reserves, it was reported that over 3.4 billion barrels of oil are in Kentucky tar sand deposits alone. In the 22,000 acres, estimated reserves are over 100 million barrels of recoverable heavy oil. The oil-impregnated section of the deposit ranges in heavy oil content from five gallons per ton to over fifteen gallons per ton. The ore body is up to thirty-five feet thick and the overall stripping ratio for a commercial plant is estimated to be one cubic yard of undisturbed overburden material per ton of tar sand ore. A shovel and truck-type strip mining operation would be used to provide feedstock to the plant.

Kelley, M.N.; Jones, H.D. II; Lewis, F.W.

1985-03-01

124

Asbestos in play sand  

SciTech Connect

A letter in the New England Journal of Medicine (Oct. 2 issue) stated that a carbonate sand marketed in New Jersey was contaminated with 2 to 4 percent tremolite asbestos. The authors were called on by one of the federal agencies to repeat the analysis of this sand, specifically for its asbestos content. The sand was pulverized and immersed in oils with known refractive indexes, and the predominant amphibole was characterized by polarized light microscopy. The optical characteristics were noted, and the indexes of refraction were measured and found to be consistent with tremolite. On the basis of optical characterization, the authors concluded that all the tremolite visualized with light microscopy consisted of large, single cleavage fragments and was not asbestiform. They used the technique of x-ray diffraction, as did the author of the original report, which showed the presence of an amphibole mineral (probably tremolite) in the carbonate sand. The technique was not used, and cannot be used, to distinguish between the tremolite habits (asbestiform or nonasbestiform). An acid-insoluble residue, recovered from the carbonate sand, was examined by analytic electron microscopy. The tremolite grains were observed to consist of single untwinned, crystalline fragments. Few defects were noted. Selected area electron diffraction nets were indicative of fragments lying near or at the common amphibole cleavage plane. These characteristics are consistent with cleavage fragments and not asbestos. Aspect ratios reflected short particles (less than 5.1). On the basis of their examination of the carbonate play sand, they conclude that it did not contain tremolite asbestos.

Langer, A.M.; Nolan, R.P.

1987-04-02

125

Sound-Producing Sand Avalanches  

NSDL National Science Digital Library

This site presents an analysis of the theories and experiments done so far on sound-producing (e.g., roaring, booming) sand avalanches. Several reference articles are cited, and a link to the summary of an article, "Booming Sand", in Scientific American volume 277, number 3, is provided. An on site version of another article, "Sound Producing Sand Avalanches", in Contemporary Physics, volume 38, number 5, is also presented in three different formats: PDF, HTML, and Postscript Preprint.The other main features of this site are sound recordings of booming sand, compressed squeaking sand, and croaking sand, as well as, and images and micrographs of booming dunes.

Bretz, Michael; Nori, Franco; Sholtz, Paul

2007-05-18

126

Gas percolation through sand  

NASA Astrophysics Data System (ADS)

Previous research has determined the shock properties of quartz sand. The effect of the physical processes occurring with varying moisture content and particle size were shock presented. In this study the same quartz sand, in a column is subjected to blast waves over a range of pressure. The diagnostics used are pressure sensors and high-speed photography. The effect of grain size on propagation time and the effect of moisture content are determined. Aspects of particle and liquid movement are also discussed. While the velocity of the percolation through the bed is primarily controlled by grain size the effect of moisture and liquids reveals a more complex dependence.

Proud, W. G.

2014-05-01

127

Oil from deep sands  

Microsoft Academic Search

Near Cold Lake, in NE Alberta, Esso Resources Canada Ltd. proposes to build a massive commercial plant to tap rich reserves of bitumen, or heavy oil, buried deep in sands approximately 1600 ft below the ground. The in situ steam injection extraction technique which is planned has been tested in pilot plants at the site for the past 17 yr.

2009-01-01

128

Sand and sandstone  

SciTech Connect

Here is a new, second edition of a classical textbook in sedimentology, petrology, and petrography of sand and sandstones. It has been extensively revised and updated, including: new techniques and their utility; new literature; new illustrations; new, explicitly stated problems for the student; and a wider scope.

Pettijohn, F.J.; Potter, P.E.; Siever, R.

1987-01-01

129

Sand and gravel  

Microsoft Academic Search

Sand and gravel are, and will continue to be, among the most important construction and industrial materials in the United States. It is the only mineral commodity produced in all 50 States. It is the principal ingredient in many houses, office buildings, highways, dams, airport runways, bridges, canals, and in glass for bottles and house and automobile windows. Also, it

J. R. Evans

1978-01-01

130

Ganges Chasma Sands  

NASA Technical Reports Server (NTRS)

8 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark, windblown sand in the form of dunes and a broad, relatively flat, sand sheet in Ganges Chasma, part of the eastern Valles Marineris trough complex. The winds responsible for these dunes blew largely from the north. Sand dunes on Mars, unlike their Earthly counterparts, are usually dark in tone. This is a reflection of their composition, which includes minerals that are more rich in iron and magnesium than the common silica-rich dunes of Earth. Similar dark sands on Earth are found in volcanic regions such as Iceland and Hawaii. A large dune field of iron/magnesium-rich grains, in the form fragments of the volcanic rock, basalt, occurs south of Moses Lake, Washington, in the U.S.

Location near: 7.7oS, 45.3oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Spring

2005-01-01

131

Northern Sand Sea  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

This VIS image was taken at 82 degrees North latitude during Northern spring. The image is completely dominated by dunes. In sand 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.

Image information: VIS instrument. Latitude 82.2, Longitude 152.5 East (207.5 West). 19 meter/pixel resolution.

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.

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.

2005-01-01

132

Flume experiment on the development of isolated dunes via sand patches and protodunes  

NASA Astrophysics Data System (ADS)

Continuous but small rate of sand supply onto a solid surface where there is no available sand can cause the formation of isolated sand dunes. In early field works, low-relief sand topographies such as sand patches and protodunes were regarded as precursors of dunes (Kocurek et al., 1992). Processes of the generation of precursors and the development to mature dunes, however, are still to be investigated. In order to observe the whole formative process of isolated dunes from the state of no available sand, as well as to elucidate the topographic features and formative conditions of precursors of dunes, a series of flume experiments were conducted.in a circular water flume. The circular water flume consists of cylindrical channel characterized by periodic boundary (without flume ends) that makes it easy to control total amount of sand in the channel. In the experiment, a known amount of very fine sand was put in the channel at first. The sand was suspended from the flume bottom by exerting a strong water flow, and then the flow velocity was reduced to a desired value when an experimental run get started. During the run, a given amount of sand was supplied at a constant interval. Although the rate of sand supply was different, similar structures appeared in all experimental runs. At first stage of experimental runs, the bottom was covered with low-relief sand streaks. These streaks lay parallel to the stream line. With increasing the amount of available sand, small sand patches emerge on the sand streaks, and then the patches linked laterally and became transverse protodunes. Finally, slipfaces was formed on the leeward slope of the transverse topography, i.e. the topography grew into mature dune.

Taniguchi, K.; Endo, N.

2013-12-01

133

Oil sands fulfill their promise  

Microsoft Academic Search

The Great Canadian Oil Sands plant, a $300 million investment for Sun Oil Co., is the first commercial facility to wrest oil from the Alberta tar sands. Energy companies are poised to invest more than $3 billion in oil sands development in the next several years. Construction already underway, planning for projects to come, and the widening scope of oil

Chaapel

2009-01-01

134

Special report: Athabasca tar sands  

Microsoft Academic Search

A synthetic crude oil is being produced from the Athabasca oil sands region of northeastern Alberta. The Athabasca operations are broken down into 3 divisions: mining, extraction of oil from the sand, and pipelining to market. The entire project, operated by Great Canadian Oil Sands, Ltd., an affiliate of Sun Oil Co., is self-sufficient except for the water supply. By-

W. A. Bachman; D. H. Stormont

1967-01-01

135

Sand accumulation around porous fences  

Microsoft Academic Search

A computer model is developed to calculate the average monthly and annual rates of potential sand drift over a specific study area. The basic formula adopted for calculating potential sand drift due to wind blowing in a certain direction, speed and height above the drifted surface is given by Bagnold (1936, 1954). The accumulated sand profiles with time, around a

Nabil A. Zaghloul

1997-01-01

136

Depositional and diagenetic history of Bodcaw Sand, Cotton Valley Group (Upper Jurassic), Longwood field, Caddo Parish, Louisiana  

Microsoft Academic Search

The Bodcaw Sand contains fine-grained sandstones and siltstones deposited within a barrier-bar sequence. Based on vertical changes in sedimentary structures, texture, and mineralogic composition, three distinct lithofacies (upper, middle, and lower shoreface) within the Bodcaw Sand and two associated logoonal lithofacies were identified. Cross-stratification and low-angle laminations, rarely disrupted by biogenic structures, characterize the fine-grained upper shoreface sandstones. Middle shoreface

A. A. Sartin

1984-01-01

137

Sand hazards on tourist beaches.  

PubMed

Visiting the beach is a popular tourist activity worldwide. Unfortunately, the beach environment is abundant with hazards and potential danger to the unsuspecting tourist. While the traditional focus of beach safety has been water safety oriented, there is growing concern about the risks posed by the sand environment on beaches. This study reports on the death and near death experience of eight tourists in the collapse of sand holes, sand dunes, and sand tunnels. Each incident occurred suddenly and the complete burial in sand directly contributed to the victims injury or death in each case report. PMID:23290717

Heggie, Travis W

2013-01-01

138

Simultaneous nitrification-denitrification in slow sand filters.  

PubMed

While the ability of slow sand filters to remove total suspended solids (SS), turbidity, and organics from wastewaters is well known, this study has demonstrated that they can also achieve simultaneous nitrification-denitrification, producing effluent total Kjedahl nitrogen (TKN) and total nitrogen (TN) concentrations as low as 0.6 and 1.5mg/l, respectively, utilizing particulate and slowly biodegradable COD in the process. The impact of filtration rates in the range of 0.15-0.38m/h, filter depth of 0.5-1.5m, and sand size 0.3-0.5mm on nitrogen removal processes at temperatures of 10-39 degrees C was assessed. Nitrification efficiency, denitrification efficiency, and total nitrogen removal efficiency correlated well with filtration rate and sand size only, with all three parameters inversely proportional to the square root of the aforementioned two process variables. Nitrification exhibited the most sensitivity to filtration rate and sand size. The filters produced effluent with turbidities of 0.1-0.5 NTU, SS concentrations of 3-6mg/l in the fine sand and 6-9mg/l in the coarse sand. Effluent BOD(5) and COD concentrations were mostly in the 0.8-2.6 and 15-34mg/l range, respectively. PMID:12493214

Nakhla, George; Farooq, Shaukat

2003-01-31

139

Shear Band Formation in Plane Strain Experiments of Sand  

NASA Technical Reports Server (NTRS)

A series of biaxial (plane strain) experiments were conducted on three sands under low (15 kPa) and high (100 kPa) confining pressure conditions to investigate the effects of specimen density, confining pressure, and sand grain size and shape on the constitutive and stability behavior of granular materials. The three sands used in the experiments were fine-, medium-, and coarse-grained uniform silica sands with rounded, subangular, and angular grains, respectively. Specimen deformation was readily monitored and analyzed with the help of a grid pattern imprinted on the latex membrane. The overall stress-strain behavior is strongly dependent on the specimen density, confining pressure, sand grain texture, and the resulting failure mode(s). That became evident in different degrees of softening responses at various axial strains. The relationship between the constitutive behavior and the specimens' modes of instability is presented. The failure in all specimens was characterized by two distinct and opposite shear bands. It was found that the measured dilatancy angles increase as the sand grains' angularities and sizes increase. The measured shear band inclination angles are also presented and compared with classical Coulomb and Roscoe solutions.

Alshibli, Khalid A.; Sture, Stein

2000-01-01

140

Modern analog for deep-water deposition of shallow-water Pliocene Sands, Gulf of Mexico  

SciTech Connect

Paleoenvironmental studies using benthic foraminifers and total fauna can be used to identify displaced shallow-water sands. A productive sand in Eugene Island field, which has a high resistivity but suppressed spontaneous-potential, was conventionally cored to determine reservoir characteristics and environment of deposition. Grain-size analysis shows a composition of very fine sand with a large silt and clay component. Studies of sand-size distribution throughout the 13-ft core did not reveal graded bedding, thus excluding turbidity currents as a depositional mechanism. Analysis of the benthic fauna within the sand unit indicates that the sands and thin-bedded shales were originally deposited on the inner to middle shelf. The occurrence of bathyal shale above and below the productive unit suggests that the shallow-water sands were transported basinward into a slope environment. Regional paleobathymetric maps indicate that there was a progradation of the shelf edge during deposition of the sand unit. This evidence, along with the fine-grained character of the sands, suggests that a deltaic complex was developing updip of the field. The depositional environment is very similar to that described by J.M. Coleman and others near the modern Mississippi River Delta. The processes that are moving shallow-water sands across the shelf, stimulating mass movement and shelf-ridge slumping, were also active around ancient deltas. Based on the modern analog, it is interpreted that the field sand is part of a debris flow initiated by shelf-edge failure. The geometry of the sand unit also supports this hypothesis.

Kohl, B.

1985-02-01

141

Polar Sand Dunes  

NASA Technical Reports Server (NTRS)

MGS MOC Release No. MOC2-495, 26 September 2003

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown sand dunes in Chasma Boreale, a wide trough in the north polar region of Mars. The dunes are shown here in their summertime configuration; that is, they are not covered with seasonal frost. The dunes are dark because the grains that make up these sandy landforms consist of dark minerals and/or fragments of dark-toned rock. The steepest slopes on these dunes, their slipfaces, point toward the top/upper left (northwest), indicating that winds blow the sand from the lower right (southeast). This picture is located near 84.7oN, 359.3oW, and covers an area 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

2003-01-01

142

Magic Sand: Nanosurfaces  

NSDL National Science Digital Library

This is an activity/demo in which learners are exposed to the difference bewteen hydrophobic surfaces (water repelling) and hydrophilic surfaces (water loving). This activity also demonstrates how changing the size of material to nanoscale changes its behavior at the macroscale. The instructions assume that Magic Sand is performed as a demonstration, but it works great a a hands-on activity as well.

Network, Nanoscle I.; Wisconsin-Madison, University O.

2012-06-26

143

Western gas sands  

SciTech Connect

The purpose of this research is to demonstrate the feasibility of economically producing natural gas from low-permeability reservoirs. Two broad research goals have been defined: (1) reducing the uncertainty of the reservoir production potential, and (2) improving the extraction technology. These goals are being pursued by conducting research and encouraging industrial efforts in developing the necessary technology, including: (1) providing fundamental research into the nature of tight, lenticular gas sands and the technologies for diagnosing and developing them: (2) developing and verifying the technology for effective gas production; and (3) promoting the transfer of research products and technology advances to the gas industry in usable forms. The focus of the research for the last several years has been improving diagnostic instrumentation for reservoir and stimulation performance evaluation, geophysical and engineering interpretation, and stimulation techniques. Integrated geologic studies of three basins containing tight lenticular sands, which were selected by DOE as priority research targets, have also been pursued as part of this new effort. To date, the following tentative conclusions have been formed: Permeability of the tight gas sands can be as much as three to four orders of magnitude lower than that of conventional gas deposits. Nineteen western geologic basins and trends containing significant volumes of tight gas have been identified. Gas resources in the priority geologic basins have been estimated - Piceance Basin 49 Tcf.; Greater Green River Basin, 136 Tcf.; Uinta Basin, 20 Tcf. Presence of natural micro-fractures within a reservoir and the effective propped length of hydraulically induced fratures are the critical parameters for successful development of tight sand resources. Stimulation technology at the present time is insufficient to efficiently recover gas from lenticular tight reservoirs. 8 figs., 3 tabs.

Not Available

1985-03-01

144

Prediction of sedimentation and consolidation of fine tails  

Microsoft Academic Search

Sedimentation and consolidation of suspensions of fine particles were analyzed by integrating experimental measurement of properties in a centrifuge with a comprehensive numerical model. The yield stress and settling velocity for tailings from tar sands extraction were determined experimentally as a function of the volume fraction of solids. The evaluated state functions were used to simulate batch settling and consolidation,

William F. Eckert; Jacob H. Masliyah; Murray R. Gray; Phillip M. Fedorak

1996-01-01

145

The extraction of bitumen from western oil sands: Volume 2. Final report  

SciTech Connect

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-bed bitumen recovery and coked sand combustion; (2) water-based recovery of bitumen; (3) oil sand pyrolysis in a continuous rotary kiln reactor; (4) oil sand pyrolysis in a large diameter fluidized bed reactor; (5) oil sand pyrolysis in a small diameter fluidized bed reactor; (6) combustion of spent sand in a transport reactor; (7) recovery and upgrading of oil sand bitumen using solvent extraction methods; (8) fixed-bed hydrotreating of Uinta Basin bitumens and bitumen-derived hydrocarbon liquids; (9) ebullieted bed hydrotreating of bitumen and bitumen derived liquids; (10) bitumen upgrading by hydropyrolysis; (11) evaluation of Utah`s major oil sand deposits for the production of asphalt, high-energy jet fuels and other specialty products; (12) characterization of the bitumens and reservoir rocks from the Uinta Basin oil sand deposits; (13) bitumen upgrading pilot plant recommendations; (14) liquid-solid separation and fine tailings thickening; (15) in-situ production of heavy oil from Uinta Basin oil sand deposits; (16) oil sand research and development group analytical facility; and (17) process economics. This volume contains reports on nine of these projects, references, and a bibliography. 351 refs., 192 figs., 65 tabs.

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

1997-11-26

146

Assessment of the KE Basin Sand Filter Inventory In Support of Hazard Categorization  

SciTech Connect

In 1978, the water cleaning system for the KE Basin was upgraded by adding a sand filter and ion exchange columns. Basin water containing finely divided solids is collected by three surface skimmers and pumped to the sand filter. Filtrate from the sand filter is further treated in the ion exchange modules. The suspended solids accumulate in the sand until the pressure drop across the filter reaches established operating limits, at which time the sand filter is backwashed. The backwash is collected in the NLOP, where the solids are allowed to settle as sludge. Figure 2-1 shows a basic piping and instrumentation diagram depicting the relationship among the basin skimmers, sand filter, and NLOP. During the course of deactivation and decommissioning (D&D) of the K-Basins, the sand filter and its media will need to be dispositioned. The isotopic distribution of the sludge in the sand filter has been estimated in KE Basin Sand Filter Monolith DQO (KBC-24705). This document estimates the sand filter contribution to the KE hazard categorization using the data from the DQO.

Ross, Steven B.; Young, Jonathan

2005-09-28

147

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

148

Fine Arts Evaluation.  

ERIC Educational Resources Information Center

The fine arts as defined by the Ministry of Education (British Columbia) include music, art, and drama with the curriculum focusing on two concepts: creation and appreciation. One of the aims of School District #68 (Nanaimo) is to provide students with the opportunity to gain exposure to, and experience in, fine arts. The Fine Arts Evaluation…

Nanaimo School District #68 (British Columbia).

149

Investigation of guided waves propagation in pipe buried in sand  

NASA Astrophysics Data System (ADS)

The inspection of pipelines by guided wave testing is a well-established method for the detection of corrosion defects in pipelines, and is currently used routinely in a variety of industries, e.g. petrochemical and energy. When the method is applied to pipes buried in soil, test ranges tend to be significantly compromised because of attenuation of the waves caused by energy radiating into the soil. Moreover, the variability of soil conditions dictates different attenuation characteristics, which in-turn results in different, unpredictable, test ranges. We investigate experimentally the propagation and attenuation characteristics of guided waves in pipes buried in fine sand using a well characterized full scale experimental apparatus. The apparatus consists of an 8 inch-diameter, 5.6-meters long steel pipe embedded over 3 meters of its length in a rectangular container filled with fine sand, and an air-bladder for the application of overburden pressure. Longitudinal and torsional guided waves are excited in the pipe and recorded using a transducer ring (Guided Ultrasonics Ltd). Acoustic properties of the sand are measured independently in-situ and used to make model predictions of wave behavior in the buried pipe. We present the methodology and the systematic measurements of the guided waves under a range of conditions, including loose and compacted sand. It is found that the application of overburden pressure modifies the compaction of the sand and increases the attenuation, and that the measurement of the acoustic properties of sand allows model prediction of the attenuation of guided waves in buried pipes with a high level of confidence.

Leinov, Eli; Cawley, Peter; Lowe, Michael J. S.

2014-02-01

150

Recycling of PET bottles as fine aggregate in concrete  

SciTech Connect

An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365 days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility.

Frigione, Mariaenrica, E-mail: mariaenrica.frigione@unisalento.i [Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce (Italy)

2010-06-15

151

Sand dollar sites orogenesis  

NASA Astrophysics Data System (ADS)

The determinology of the humble sand dollars habitat changing from inception to the drastic evolution of the zone to that of present day. Into the cauldron along the southern Californian 'ring of fire' lithosphere are evidence of geosynclinals areas, metasedimentary rock formations and hydrothermal activity. The explanation begins with 'Theia' and the Moon's formation, battles with cometary impacts, glacial ages, epochs with evolutionary bottlenecks and plate tectonics. Fully illustrated the lecture includes localised diagrams and figures with actual subject photographic examples of plutonic, granitic, jade and peridodite. Finally, the origins of the materials used in the lecture are revealed for prosecution by future students and the enjoyment of interested parties in general.

Amos, Dee

2013-04-01

152

Imperial Sand Dunes  

NSDL National Science Digital Library

The Bureau of Land Management presents the current news, projects, and the geologic and cultural history of the Imperial Sand Dunes at this website. Users can easily search through an abundance of remarkable images of dunes as well as other Californian landscapes. The website offers links to the current rules, regulations, and management plans. Individuals, who will be traveling to the area, can find the weather forecast, an events calendar, and information on volunteering. Visitors can locate archives of Federal Register Notices as well as news releases.

153

Deceleration of projectiles in sand  

NASA Astrophysics Data System (ADS)

Penetration of projectiles was measured for hemispherical and conical nose shapes penetrating granular media. Targets were beds of Ottawa sand and Eglin sand. Projectiles were rigid metals. Experimental parameters that were varied included velocity (from 300 to 600 m/s), nose shape, sand density, and scale (from 5 mm to 20 mm). Strong evidence for scale effects is found: 5 mm diameter projectiles are less effective penetrators than 12.5, 15, or 20 mm diameter penetrators.

Bless, Stephan; Cooper, William; Watanabe, Keiko; Peden, Robert

2012-03-01

154

Beach Sands Along the California Coast are Diffuse Sources of Fecal Bacteria to Coastal Waters  

NASA Astrophysics Data System (ADS)

Fecal indicator bacteria (FIB) are nearly ubiquitous in California (CA) beach sands. Sands were collected from 55 beaches along the CA coast. Ninety-one percent of the beaches had detectable enterococci (ENT) while 62% had detectable E. coli (EC) in their sands. The presence of a putative bacterial source (such as a river), the degree of wave shelter, and surrounding land use explained a significant (p<0.05) fraction of the variation in both ENT and EC densities between beaches. Sand characteristics including moisture content, organic carbon, and percent fines, significantly (p<0.05) influenced only EC densities in beach sand. We assayed 34 of 163 sand samples for salmonellae, but did not detect this bacterial pathogen. The potential for FIB to be transported from the sand to sea was investigated at a single wave-sheltered beach with high densities of ENT in beach sand: Lovers Point, CA (LP). We collected samples of exposed and submerged sands as well as water over a 24 h period in order to compare the disappearance or appearance of ENT in sand and the water column. Exposed sands had significantly higher densities of ENT than submerged sands with the highest densities located near the high tide line. Water column ENT densities began low, increased sharply during the first flood tide and slowly decreased over the remainder of the study. During the first flood tide, the number of ENT that entered the water column was nearly equivalent to the number of ENT lost from exposed sands when they were submerged by seawater. The decrease in nearshore ENT concentrations after the initial influx can be explained by ENT die-off and dilution with clean ocean water. A source tracking study at LP indicated that ENT were likely of human origin because they were positive for the esp gene.

Boehm, A. B.; Yamahara, K.; Layton, B.

2007-05-01

155

Identification and delineation of low resistivity, low permeability reservoirs using qualitative sidewall sample log k * S[sub O] relationships in the western shallow oil zone, Elk Hills Field, California  

Microsoft Academic Search

Over 500 wells, including wells producing from the deeper Miocene Stevens sands, penetrate the Western Shallow Oil Zone (Pliocene Etchegoin Formation) at the Elk Hills Naval Petroleum Reserve in California. The Western Shallow Oil Zone Gusher and Calitroleum sands are very fine grained, silty and pyritic and are interbedded with silty shales. Electric logs generally show 1[1\\/2]-2[1\\/2] ohm-meters of deep

E. K. Beacom; I. S. Kornreich

1996-01-01

156

Source area, depositional environment, and composition of Quaternary sands, Monterey Bay, California  

SciTech Connect

A suite of 173 sand samples from the Monterey Bay region was studied, using a stepwise discriminant function analysis, to determine the role of source area and depositional environment in controlling the modal framework constituents of the sands. These medium to fine-grained sands were derived from the Salines, Pajaro, and Carmel drainage basins, and were deposited in fluvial, nearshore marine, and eolian environments. They range in age from recent to early Pleistocene. Provenance exerts the most significant control on composition, providing an 87% assignment efficiency (independent of depositional environment); volcanic and sedimentary rock fragments were the most important variables. There was a 100% efficiency when discriminating between fluvial sands from the three drainage basins; however, the efficiencies were less strong in marine and eolian sands (90.5 and 86%, respectively). This difference is, in part, the result of modification in transit and mixing of sources.

O'Brien, W.D. Jr.; Dupre, W.R.

1988-01-01

157

Augmenting Sand Simulation Environments through Subdivision and Particle Refinement  

NASA Astrophysics Data System (ADS)

Recent advances in computer graphics and parallel processing hardware have provided disciplines with new methods to evaluate and visualize data. These advances have proven useful for earth and planetary scientists as many researchers are using this hardware to process large amounts of data for analysis. As such, this has provided opportunities for collaboration between computer graphics and the earth sciences. Through collaboration with the Oregon Space Grant and IGERT Ecosystem Informatics programs, we are investigating techniques for simulating the behavior of sand. We are also collaborating with the Jet Propulsion Laboratory's (JPL) DARTS Lab to exchange ideas and gain feedback on our research. The DARTS Lab specializes in simulation of planetary vehicles, such as the Mars rovers. Their simulations utilize a virtual "sand box" to test how a planetary vehicle responds to different environments. Our research builds upon this idea to create a sand simulation framework so that planetary environments, such as the harsh, sandy regions on Mars, are more fully realized. More specifically, we are focusing our research on the interaction between a planetary vehicle, such as a rover, and the sand beneath it, providing further insight into its performance. Unfortunately, this can be a computationally complex problem, especially if trying to represent the enormous quantities of sand particles interacting with each other. However, through the use of high-performance computing, we have developed a technique to subdivide areas of actively participating sand regions across a large landscape. Similar to a Level of Detail (LOD) technique, we only subdivide regions of a landscape where sand particles are actively participating with another object. While the sand is within this subdivision window and moves closer to the surface of the interacting object, the sand region subdivides into smaller regions until individual sand particles are left at the surface. As an example, let's say there is a planetary rover interacting with our sand simulation environment. Sand that is actively interacting with a rover wheel will be represented as individual particles whereas sand that is further under the surface will be represented by larger regions of sand. The result of this technique allows for many particles to be represented without the computational complexity. In developing this method, we have further generalized these subdivision regions into any volumetric area suitable for use in the simulation. This is a further improvement of our method as it allows for more compact subdivision sand regions. This helps to fine tune the simulation so that more emphasis can be placed on regions of actively participating sand. We feel that through the generalization of our technique, our research can provide other opportunities within the earth and planetary sciences. Through collaboration with our academic colleagues, we continue to refine our technique and look for other opportunities to utilize our research.

Clothier, M.; Bailey, M.

2012-12-01

158

The Halekulani Sand Channel and Makua Shelf sediment deposits: Are they a sand resource for replenishing Waikiki's beaches?  

USGS Publications Warehouse

The Halekulani Sand Channel and the Makua Shelf off the south shore of Oahu contain at least 1.3 million m3 of sediment that is a possible resource for nourishing degraded sections of Waikiki Beach. A sidescan sonar survey indicates continuous sediment cover within the channel and on the shelf, and samples from the top and bottom of vibracores from the channel and shelf contain from 29% to 77% of grains between 0 to 2.5 phi (1 to 0.177 mm), the size range of four samples from Waikiki Beach. Compositional analyses indicate high variability, but the vibracore samples normally have relatively high Halimeda content compared to beach sand samples. Laboratory tests show a positive correlation of abrasion with Halimeda content, suggesting that the offshore sediment would abrade more than beach sediment under nearshore wave action. The common gray color of the offshore sediment can be aesthetically undesirable for sand on popular tourist beaches such as Waikiki; however, visual observation of native beach sand indicates that a significant component of gray color is endemic to many Hawaiian beaches. The gray color was removed in the laboratory by soaking in heated hydrogen peroxide. The geological properties of the offshore sediment indicate potential as a resource for beach nourishment, but industrial treatment might be necessary to remove excess fine and coarse grains, and possibly the gray color. Further, the abrasion potential might have to be considered in calculating beach sand losses over time.

Hampton, M. A.; Fletcher, III, C. H.; Barry, J. H.; Lemmo, S. J.

2000-01-01

159

Vacuum Head Removes Sanding Dust  

NASA Technical Reports Server (NTRS)

Vacuum sander prevents sanding dust from entering a work area, since dust particles are drawn off as quickly as they are produced. Tool is useful where dust presents health hazards, interferes with such processes as semiconductor manufacture, or could destroy wet paint or varnish finishes. Could be used to sand such materials as lead paint.

Bengle, C. G.; Holt, J. W.

1982-01-01

160

Sand and Dust on Mars  

NASA Technical Reports Server (NTRS)

Mars is a planet of high scientific interest. Various studies are currently being made that involve vehicles that have landed on Mars. Because Mars is known to experience frequent wind storms, mission planners and engineers require knowledge of the physical and chemical properties of Martian windblown sand and dust, and the processes involved in the origin and evolution of sand and dust storms.

Greeley, Ronald; Haberle, Robert M.

1991-01-01

161

Sand pictures : what's missing?  

NSDL National Science Digital Library

This activity opens with pictures of traditional African sand paintings called sonas. A sona is comprised of dots and loops. One design is missing, and students are asked to study the patterns and determine the appearance of the missing design. The activity, part of the Figure This! collection of 80 math challenges emphasizing real world math, explains the importance of mathematical patterns in archaeology and cultural anthropology. The Hint suggests that students examine the number and arrangement of dots and their relationship to the loops and squares in the designs. Multiple ways to analyze the pattern are given in the solution. Related questions ask students to develop a mathematical formula to express a pattern of dots and to draw lines to connect dots in an array. Answers to all questions and additional resources are provided. Copyright 2005 Eisenhower National Clearinghouse

National Council of Teachers of Mathematics (NCTM)

2002-01-01

162

Sand and Water  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 7 November 2003

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 sand 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 sand that has accumulated into one large dune with a single curvilinear crest.

Image information: VIS instrument. Latitude -54.9, Longitude 17.5 East (342.5 West). 19 meter/pixel resolution.

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.

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.

2003-01-01

163

Particle size conditions water repellency in sand samples hydrophobized with stearic acid  

NASA Astrophysics Data System (ADS)

The main objective of this research is to study the effects of particle size and soil moisture on water repellency (WR) from hydrophobized sand samples. Quartz sand samples were collected from the top 15 cm of sandy soils, homogenised and divided in different sieve fractions: 0.5 - 2 mm (coarse sand), 0.25 - 0.5 mm (medium sand), and 0.05 - 0.25 mm (fine sand). WR was artificially induced in sand samples using different concentrations of stearic acid (SA; 0.5, 1, 5, 10, 20 and 30 g kg-1). Sand samples were placed in Petri plates and moistened with distilled water until 10% water content in weight. After a period of 30 min, soil WR was determined using the water drop penetration time (WDPT) test. A set of sub-samples was placed in an oven (50 oC) during the experimental period, and the rest was left air-drying at standard laboratory conditions. Water repellent soil samples were used as control, and the same treatments were applied. WR was determined every 24 h. No changes in WR were observed after 6 days of treatment. As expected, air-dried fine sand samples showed WR increasing with SA concentration and decreasing with soil moisture. In contrast, oven-dried samples remained wettable at SA concentrations below 5 g kg-1. Fine sand oven-dried samples showed extreme WR after just one day of treatment, but air-dried samples did not show extreme repellency until three days after treatment. SA concentrations above 5 g kg-1 always induced extreme WR. Medium sand air-dried samples showed hydrophilic properties when moist and low SA concentration (£1 g kg-1), but strong to extreme WR was induced by higher SA concentrations. In the case of oven-dried samples, medium sand showed severe to extreme WR regardless of soil moisture. Coarse sand showed the longest WDPTs, independently of soil moisture content or SA concentration. This behaviour may be caused by super-hydrophobicity. Also, it is suggested that movements of sand particles during wetting, contribute to expose new intact hydrophobic surfaces in contact with water, causing longer WDPTs. The re-organization of polar molecules in the hydrophobic coating of particles may contribute to develop extreme WR. Soil WR from control samples varied between strong and severe WR, and did not show strong differences with soil moisture content.

González-Peñaloza, F. A.; Jordán, A.; Bellinfante, N.; Bárcenas-Moreno, G.; Mataix-Solera, J.; Granged, A. J. P.; Gil, J.; Zavala, L. M.

2012-04-01

164

Characterization of Fine Powders  

NASA Astrophysics Data System (ADS)

Fine powders are used in many applications and across many industries such as powdered paints and pigments, ceramics, petrochemicals, plastics, pharmaceuticals, and bulk and fine chemicals, to name a few. In addition, fine powders must often be handled as a waste by-product, such as ash generated in combustion and gasification processes. In order to correctly design a process and process equipment for application and handling of powders, especially fine powders, it is essential to understand how the powder would behave. Many characterization techniques are available for determining the flow properties of powders; however, care must be taken in selecting the most appropriate technique(s).

Krantz, Matthew; Zhang, Hui; Zhu, Jesse

165

Clay minerals in nonaqueous extraction of bitumen from Alberta oil sands  

Microsoft Academic Search

A non-aqueous bitumen extraction process was studied where only toluene and heptane, with no water additions, were used to extract bitumen from two Alberta oil sands ore samples. One sample had a high bitumen (13.5wt.%) and low fine (5.3wt.%<45?m) contents, while the other sample had an intermediate bitumen (10.5wt.%) and high fine (23.3wt.%) contents. Bitumen recovery and product quality were

Ali Hooshiar; Peter Uhlik; Qi Liu; Thomas H. Etsell; Douglas G. Ivey

166

Hardfacing fights wear in oil sands operation  

SciTech Connect

Wear attack is responsible for high production losses and over $40 million per year in equipment repairs and replacement costs at Syncrude`s synthetic crude oil plant near Fort McMurray in Northern Alberta. Most of this damage is caused by the fine quartz particle constituents which predominate in oil sands. It occurs in a multiplicity of forms which can be classified into three primary mechanisms: Sliding abrasive wear and sporadic impact, which affects mainly mining equipment; Slurry abrasion and erosion, which occur in bitumen extraction, separation plants, and in tailings lines; and High-temperature erosion, which is often augmented by corrosion in bitumen upgrading operations. Process streams in this area also contain fine coke particles and catalyst debris. The paper gives an overview of Syncrude`s operations in mining, extraction, and upgrading, then describes the following: wear materials and protection systems, surface engineering systems, weld deposited hardfacing, benefits, surface modification system experience, thermal spray coating experience, disk centrifuge bowls, investigation of plasma arc spraying, and combating pump erosion.

Llewellyn, R.; Tuite, C. [Syncrude Canada Ltd., Edmonton, Alberta (Canada)

1995-03-01

167

Simulating Sand Behavior through Terrain Subdivision and Particle Refinement  

NASA Astrophysics Data System (ADS)

Advances in computer graphics, GPUs, and parallel processing hardware have provided researchers with new methods to visualize scientific data. In fact, these advances have spurred new research opportunities between computer graphics and other disciplines, such as Earth sciences. Through collaboration, Earth and planetary scientists have benefited by using these advances in hardware technology to process large amounts of data for visualization and analysis. At Oregon State University, we are collaborating with the Oregon Space Grant and IGERT Ecosystem Informatics programs to investigate techniques for simulating the behavior of sand. In addition, we have also been collaborating with the Jet Propulsion Laboratory's DARTS Lab to exchange ideas on our research. The DARTS Lab specializes in the simulation of planetary vehicles, such as the Mars rovers. One aspect of their work is testing these vehicles in a virtual "sand box" to test their performance in different environments. Our research builds upon this idea to create a sand simulation framework to allow for more complex and diverse environments. As a basis for our framework, we have focused on planetary environments, such as the harsh, sandy regions on Mars. To evaluate our framework, we have used simulated planetary vehicles, such as a rover, to gain insight into the performance and interaction between the surface sand and the vehicle. Unfortunately, simulating the vast number of individual sand particles and their interaction with each other has been a computationally complex problem in the past. However, through the use of high-performance computing, we have developed a technique to subdivide physically active terrain regions across a large landscape. To achieve this, we only subdivide terrain regions where sand particles are actively participating with another object or force, such as a rover wheel. This is similar to a Level of Detail (LOD) technique, except that the density of subdivisions are determined by their proximity to the interacting object or force with the sand. To illustrate an example, as a rover wheel moves forward and approaches a particular sand region, that region will continue to subdivide until individual sand particles are represented. Conversely, if the rover wheel moves away, previously subdivided sand regions will recombine. Thus, individual sand particles are available when an interacting force is present but stored away if there is not. As such, this technique allows for many particles to be represented without the computational complexity. We have also further generalized these subdivision regions in our sand framework into any volumetric area suitable for use in the simulation. This allows for more compact subdivision regions and has fine-tuned our framework so that more emphasis can be placed on regions of actively participating sand. We feel that this increases the framework's usefulness across scientific applications and can provide for other research opportunities within the earth and planetary sciences. Through continued collaboration with our academic partners, we continue to build upon our sand simulation framework and look for other opportunities to utilize this research.

Clothier, M.

2013-12-01

168

Sand acoustics: The effective density fluid model, Pierce/Carey expressions, and inferences for porous media modeling.  

PubMed

Recently, Pierce and Carey [J. Acoust. Soc. Am. 124, EL308-EL312 (2008)] presented a low frequency analysis of sound propagation in sand/silty sediments. Here, equivalent expressions are presented using a low frequency expansion of an unconsolidated version of Biot porous medium theory. The resulting expression for attenuation allows identification of the non-dimensional parameter beta in the Pierce/Carey result in terms of physical parameters. The agreement of these two derivations motivates further analyses. The results imply that porous media propagation models that treat the medium's inertia via a single component approximation disregard a fundamental physical effect resulting from the relative inertia of the grains and fluid and are thus incomplete. PMID:19354356

Williams, Kevin L

2009-04-01

169

Hydrogeology of sand and gravel deposits near Nepaug Reservoir, New Hartford and Burlington, Connecticut  

USGS Publications Warehouse

Sand and gravel deposits near the Nepaug Reservoir in New Hartford and Burlington, Connecticut, were studied to provide a basis for ongoing investigations that will evaluate water-quality conditions in the watershed and the effects of sand and gravel mining on the quality of water in the reservoir. In the Nepaug area, surficial glacial materials overlie crystalline bedrock that is predominantly schist and gneiss. Along the western side of Nepaug Reservoir, glacial stratified deposits were laid down as ice-marginal deltas in a series of small glacial lakes that formed sequentially as the ice margin retreated northeastward through the area. These deposits are as much as 250 feet thick and are subdivided into coarse-grained units (gravel, sand and gravel, and sand deposits) and fine-grained units (very fine sand, silt, and clay deposits). Approximately 954 million cubic feet of sand and gravel is contained in four delineated deposits in two areas near the reservoir. The sand and gravel deposits adjacent to the Nepaug Reservoir can affect the physical and chemical responses of the watershed. Removal of the sand and gravel would likely result in increased streamflow peaks associated with storms and decreased streamflow during low-flow periods. Streamflow during floods and droughts at Burlington Brook and Clear Brook, a tributary to the Nepaug Reservoir, were compared to determine how the volume of sand and gravel in a watershed affects ground-water storage and the way water is released from storage. Removal of unsaturated deposits also may affect chemical interactions between water and sediment and cause changes in the amount of dissolved constituents in the water.

Stone, Janet Radway; Starn, J. Jeffrey; Morrison, Jonathan

2001-01-01

170

Batch experiments characterizing the reduction of Cr(VI) using suboxic material from a mildly reducing sand and gravel aquifer  

USGS Publications Warehouse

Batch experiments were conducted with sand collected from a shallow sand and gravel aquifer to identify the principal chemical reactions influencing the reduction of Cr(VI), so that field-observed Cr(VI) reduction could be described. The reduction appeared to be heterogeneous and occurred primarily on Fe(II)-bearing minerals. At only 1 wt %, the fine fraction (<64 ??m diameter) of the sediments dominated the amount of aqueous Cr(VI) reduction because of its greater reactivity and surface area. Although reduction of Cr(VI) increased with decreasing pH, small variations in the abundance of fine fraction among the replicate samples obscured pH trends in the batch experiments. Consistent results could only be obtained by separating the fine material from the sand and running parallel experiments on each fraction. As pH decreased (6.4 to 4.5), Cr(VI) reduction increased from 30 to 50 nmol/m2 for the sand fraction (64-1000 ??m) and from 130 to 200 nmol/m2 for the fine fraction. The amount of Cr(VI) reduced in both the sand-sized and fine material increased from 35 to 80 and from 130 to 1000 nmol/m2, respectively, for a 10-fold increase in Cr(VI)initial. A consistent description of the rate data was achieved by assuming that intraparticle diffusion limited the observed rate of reduction.

Anderson, L. D.; Kent, D. B.; Davis, J. A.

1994-01-01

171

Sedimentology and stratigraphy of tidal sand ridges southwest Florida inner shelf  

SciTech Connect

Detailed investigation of linear shelf sand ridges located off the southwest coast of Florida shows them to be tide-dominated sand bodies. These ridges are remarkably similar to the large sand 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 bed. 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 sand 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 sand with limestone clasts; (2) bioturbated muddy shelly quartz sand; and (3) well-sorted, cross-stratified quartz sand that characterizes the sand ridges themselves. Each of the tidal sand ridges displays a coarsening-upward sequence of fine, well-sorted sand. 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 sand bodies in the ancient record, especially the Mesozoic of the mid-continent area.

Davis, R.A. Jr.; Klay, J.; Jewell, P. (Univ. of South Florida, Tampa (United States))

1993-01-01

172

Experimental investigation of deformation mechanisms during shear-enhanced compaction in poorly lithified sandstone and sand  

NASA Astrophysics Data System (ADS)

Shear-enhanced compaction in shallow sandstone reservoirs has been investigated in laboratory experiments using high-pressure triaxial testing of poorly lithified sandstone and sand. We have studied the deformation mechanism involved during shear-enhanced compaction and controlling parameters for yield stress at varying confining pressures for sandstone/sand with different grain sizes, porosities, and packing. Experimental testing provides insights into the deformation mechanism during hydrostatic and axial compression of coarse- and fine-grained sands with different packing including (1) natural coarse-grained sandstone, (2) densely packed fine-grained sand, and (3) loosely packed fine-grained sand. Monitoring of deformation and ultrasonic velocity during deformation indicates porosity loss, compaction, and strain hardening for most of the samples. Visualization of deformation using pretest and posttest X-ray imaging and thin sections demonstrates localized deformation fabrics and grain damage. The results show grain rearrangement as the controlling deformation mechanism for material at low stress and high porosity, whereas for lower porosity and higher stress, grain fracturing controlled the deformation. The most pronounced localization of deformation was observed for the coarse-grained, low-porosity material. A Cam-Clay cap model was used to describe the porosity loss during compaction and shear-enhanced compaction, demonstrating large inelastic compaction with increasing confining pressure. Yield stress and end caps for poorly lithified sandstone are observed for various porosities and stress conditions and found to be lower than predicted using empirical relationships for sandstone.

Skurtveit, Elin; Torabi, Anita; Gabrielsen, Roy H.; Zoback, Mark D.

2013-08-01

173

Studies of Phlebotomine Sand Flies.  

National Technical Information Service (NTIS)

Psychodid sand flies in the subfamily Phlebotominae are medically important, hematophagus insects which are widely distributed and often abundant in the tropics. About 550 species in six genera are known with over half occurring in the New World. The lite...

D. G. Young G. B. Fairchild

1973-01-01

174

Deceleration of Projectiles in Sand  

NASA Astrophysics Data System (ADS)

Deceleration of projectiles has been measured for hemispherical and conical nose shapes penetrating granular media. Targets were beds of Ottawa sand and Eglin sand. The velocity range extended up to 600 m/s. Projectiles were rigid metals. Deceleration was measured by conventional time-of-arrival screens plus several innovative techniques: embedded EM coils, embedded optical fibers, and a photonic Doppler velocimeter (PDV), which observed the rear surface of the penetrator. Experimental parameters that were varied included velocity (from 300 to 600 m/s), sand density, and scale (from 5 mm to 25 mm). In this paper we will compare these various measurement techniques and we will show how the cavity geometry (cavitation and crushed veins of sand) and retarding stress (MdV/dt)/Avary with velocity, scale, and density.

Bless, Stephan; Cooper, William; Stone, Zach; Watanabe, Keiko; Peden, Robert

2011-06-01

175

Spherical Waves in Saturated Sand.  

National Technical Information Service (NTIS)

The Naval Surface Warfare Center needs to develop the capability to determine numerically the characteristics of a propagating stress wave in saturated sand. To provide needed experimental data, SRI International performed precision experiments with the o...

P. R. Gefken A. L. Florence M. Sanai

1996-01-01

176

Sand Reclamation Concept Definition Study.  

National Technical Information Service (NTIS)

Foundry sand reclamation methods, including wet, dry, thermal and combination processes, were reviewed to identify the state-of-the-art and needed research. The major features of the various systems are summarized. Trends were determined from input from s...

M. Granlund

1990-01-01

177

Modelling of saturated sand flux  

NASA Astrophysics Data System (ADS)

We derive a saturated sand flux model based on the previous models of Sauermann et al (2001 Phys. Rev. E 64 0313005) and Sørensen (2004 Geomorphology 59 53) and determine its parameters, as a function of the grain and fluid properties, from a comparison with wind tunnel data. We also show that dunes simulated with the new sand transport model compare well with observations of Moroccan dunes.

Durán, O.; Herrmann, H.

2006-07-01

178

Centrifuge modelling of jackups and spudcans on drained and partially drained silica sand  

Microsoft Academic Search

This paper presents selected data and analyses of centrifuge tests of spudcans and 3-leg independent leg jackup models under fully drained and partially drained conditions on medium dense fine saturated sand.Data of single spudcan models show the importance of vertical displacements in terms of ‘hardening’, and for reducing the potential for liquefaction under cyclic loading. Similarity of loadpaths under conditions

E. T. R. Dean; Y. S. Hsu; R. G. James; T. Sasakura; A. N. Schofield; Y. Tsukamoto

1997-01-01

179

Architectural characteristics of fine-grained submarine fans: A model applicable to the Gulf of Mexico  

Microsoft Academic Search

Submarine fan deposits in the Gulf of Mexico, modern and ancient, fall in the category of fine-grained, low overall sand\\/shale ratio basin-floor fans. Models published over the years that have been applied to both exploration and production are based on sand-rich fans, most of which were deposited in active margin settings. These models should not be used for the Gulf

A. H. Bouma; J. H. Coleman; H. DeV Wickens

1995-01-01

180

Tar sands. (FL74-56)  

Microsoft Academic Search

In terms of in-place deposits, tar sands are a relatively small hydrocarbon resource. Though ''small'' by comparison with coal and shale, tar sands have been commercially processed since 1968, and a second plant is now under construction. Many processes have been proposed to extract the bitumen from tar sands. These include both in-situ methods, and processing of mined tar sands.

1974-01-01

181

Alberta's oil sands in-situ pilots  

SciTech Connect

A brief description is given of the Alberta Oil Sands deposits and the current active pilots which are testing various recovery processes. The role of the Alberta Oil Sands Technology and Research Authority (AOSTRA) in these oil sands pilots is discussed, and details of six AOSTRA funded pilots in the major oil sands and heavy oil areas of Alberta are presented.

Phillips, R.S.

1981-01-01

182

Behavior of cemented sands - I. Testing  

Microsoft Academic Search

This paper is accompanied by a study on constitutive modelling issues of cemented sands. The concentration here is on experimental issues related to the triaxial testing of cemented sands. A preliminary investigation is performed aiming to identify potential effects of specimen size and slenderness on the stress-strain-strength characteristics of cemented sands. A comprehensive experimental study follows where clean sand specimens,

Ali A. Abdulla; Panos D. Kiousis

1997-01-01

183

Quasi-hydrodynamic lubrication effect of clay particles on sand grain erosion  

NASA Astrophysics Data System (ADS)

Minor changes in the mass physical properties of submerged sand beds can have significant consequences relative to bed stability against erosion. To examine the effect of small amounts of clay-sized particles in bed pore water on the critical shear stress ?c for the erosion of sand grains, flume experiments were carried out on the erosion of quartz sand beds impregnated with clay particles. Starting with no clay, as the clay mass fraction ? was increased, ?c was found to decrease below the value for pure sand ?co at ? = ?m, then reverted to ?co at ? = ?r and continued to increase above ?co as ? was increased further. Post-experimental analysis suggests that ?r is the pore space-filling fine sediment fraction above which sand erosion is significantly influenced by clay. In the range of ? ? ?m, slider-bearing type lubrication due to the viscosity of the clay-laden interstitial fluid appears to govern the dependence of ?c on ?, mimicking Petroff's law of thick-film lubrication. When ? < ?m, as ? decreases lubrication is increasingly curtailed by grain asperities, and ?c reverts ultimately to ?co at ? = 0. An equation relating ?c to ? is proposed in analogy with the quasi-hydrodynamic Stribeck function for lubrication. The observed effect of clay particles appears to be significant enough to require its consideration in coastal and estuarine sediment transport modeling. It may also be a factor in the estimation of bed stability when biological activity in the benthic boundary layer introduces fine particles in clean sand beds.

Barry, K. M.; Thieke, R. J.; Mehta, A. J.

2006-03-01

184

Analyses of fine paste ceramics  

SciTech Connect

Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

Sabloff, J A [ed.

1980-01-01

185

Fine motor control  

MedlinePLUS

... general) motor control. An example of gross motor control is waving an arm in greeting. Problems of the brain, spinal cord, peripheral nerves, muscles, or joints may all decrease fine motor control. The difficulty in speaking, eating, and writing in ...

186

Canyon dissolution of sand, slag, and crucible residues  

SciTech Connect

An alternative to the FB-Line scrap recovery dissolver was desired for the dissolution of sand, slag, and crucible (SS{ampersand}C) residues from the plutonium reduction process due to the potential generation of hydrogen gas concentrations above the lower flammability limit. To address this concern, a flowsheet was developed for the F-Canyon dissolvers. The dissolvers are continually purged with nominally 33 SCFM of air; therefore the generation of flammable gas concentrations should not be a concern. Following removal of crucible fragments, small batches of the remaining sand fines or slag chunks containing less than approximately 350 grams of plutonium can be dissolved using the center insert in each of the four annular dissolver ports to address nuclear criticality safety concerns. Complete dissolution of the sand fines and slag chunks was achieved in laboratory experiments by heating between 75 and 85 degrees Celsius in a 9.3M nitric acid/0.013M (hydrogen) fluoride solution. Under these conditions, the sand and slag samples dissolved between 1 and 3 hours. Complete dissolution of plutonium and calcium fluorides in the slag required adjusting the dissolver solution to 7.5 wt% aluminum nitrate nonahydrate (ANN). Once ANN was added to a dissolver solution, further dissolution of any plutonium oxide (PuO2) in successive charges was not practical due to complexation of the fluoride by aluminum. During the laboratory experiments, well mixed solutions were necessary to achieve rapid dissolution rates. When agitation was not provided, sand fines dissolved very slowly. Measurement of the hydrogen gas generation rate during dissolution of slag samples was used to estimate the amount of metal in the chunks. Depending upon the yield of the reduction, the values ranged between approximately 1 (good yield) and 20% (poor yield). Aging of the slag will reduce the potential for hydrogen generation as calcium metal oxidizes over time. The potential for excessive corrosion in the dissolvers was evaluated using experimental data reported in the literature. Corrosion data at the exact flowsheet conditions were not available; however, the corrosion rate for 304L stainless steel (wrought material) corrosion coupons in 10M nitric acid/0.01M hydrofluoric acid at 95 degrees Celsius was reported as 21 mils per year. If the fluoride in the dissolver is complexed with aluminum, the corrosion rate will decrease to approximately 5 mils per year.

Rudisill, T.S.; Gray, J.H.; Karraker, D.G.; Chandler, G.T.

1997-12-01

187

Review of continental shelf marine geotechnics: Distribution of soils, measurement of properties, and environmental hazards  

Microsoft Academic Search

Sands and silty sands are the predominant surficial soils of continental shelves. Cohesive fine?grained soils are typical off the mouths of large rivers, near bays and estuaries, and in basins located on the shelf. The stratigraphy of shelf soils is very poorly known for most engineering purposes, except in the vicinity of the Mississippi Delta.Vibratory coring is the most common

Adrian F. Richards; Harold D. Palmer; Michael Perlow Jr

1975-01-01

188

Groundwater Balance and Safe Yield of the coastal aquifer system in NEastern Korinthia, Greece  

Microsoft Academic Search

The northern coastal part of Korinthia prefecture can be characterized as an agrotourism center that has grown and urbanized rapidly. The area is formed of recent unconsolidated material consisting of sands, pebbles, breccias and fine clay to silty sand deposits. These deposits host the main aquifer system of the area, which depends on groundwater as a water resource. Groundwater is

K. S. Voudouris

2006-01-01

189

Sand Density as Sandpile Descriptor  

NASA Astrophysics Data System (ADS)

We investigate a collection of one-parametric families of isotropic sandpile models. The models involve the square lattice slowly accumulating the grains and quickly transferring them as the local piles become over-critical. The paper groups the sand-piles with respect to two features influencing the model dynamics. They are the value of the local transfer's stochasticity and the number of the transferred grains. Every pair generates one-parametric family of the sand-piles. The parameter reflects the relative height of an over-critical pile with respect to the incoming flow of sand. If the stochasticity disappears with the growth of the parameter, the families with the fixed number of the transferred grains have much in common with Bak et al.'s sand-pile [Phys. Rev. Lett. 59, 381 (1987)], while the families, whose over-critical piles lose all their grains, tend to the Zhang sand-pile [Phys. Rev. Lett. 63, 470 (1989)]. The families with non-disappearing variance give rise to new properties described in terms of the probability distribution of the pile heights.

Shapoval, A. B.; Shnirman, M. G.

190

Sand Dunes in Noachis Terra  

NASA Technical Reports Server (NTRS)

11 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-toned sand dunes in a crater in eastern Noachis Terra. Most big martian dunes tend to be dark, as opposed to the more familiar light-toned dunes of Earth. This difference is a product of the composition of the dunes; on Earth, most dunes contain abundant quartz. Quartz is usually clear (transparent), though quartz sand grains that have been kicked around by wind usually develop a white, frosty surface. On Mars, the sand is mostly made up of the darker minerals that comprise iron- and magnesium-rich volcanic rocks--i.e., like the black sand beaches found on volcanic islands like Hawaii. Examples of dark sand dunes on Earth are found in central Washington state and Iceland, among other places. This picture is located near 49.0oS, 326.3oW. Sunlight illuminates this scene from the upper left; the image covers an area 3 km (1.9 mi) wide.

2004-01-01

191

Nitrogen photoreduction on desert sands under sterile conditions  

PubMed Central

Sands from various geographic locations reduce N2 from the air to NH3 and traces of N2H4 on exposure to sunlight. This N2 photofixation occurs under sterile conditions on the surface of finely dispersed titanium minerals such as rutile, utilizing reducing equivalents generated through the photolysis of chemisorbed H2O. Abiological N2 photofixation is suggested to be part of the nitrogen cycle in arid and semiarid regions. It is estimated that about 10 × 105 tons of N2 is photoreduced on the total surface of the earth's deserts per year.

Schrauzer, Gerhard N.; Strampach, Norman; Hui, Liu Nan; Palmer, Miles R.; Salehi, Jahanshah

1983-01-01

192

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, III, P. J.; Corson, I. C.

2000-01-01

193

Windblown Sand in West Candor  

NASA Technical Reports Server (NTRS)

23 December 2003

West Candor Chasma, a part of the vast Valles Marineris trough system, is known for its layered sedimentary rock outcrops. It is less known for dark fields of windblown sand, but that is what occurs in the north-central part of the chasm. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, obtained in December 2003, shows the interplay of dark, wind-blown sand with buttes and mesas of layered rock in west Candor Chasma. Dark streamers of sand point toward the east/southeast (right/lower right), indicating that dominant winds blow from the west. This picture is located near 5.2oS, 75.7oW, and covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

2004-01-01

194

Influence of a dam on fine-sediment storage in a canyon river  

Microsoft Academic Search

Glen Canyon Dam has caused a fundamental change in the distribution of fine sediment storage in the 99-km reach of the Colorado River in Marble Canyon, Grand Canyon National Park, Arizona. The two major storage sites for fine sediment (i.e., sand and finer material) in this canyon river are lateral recirculation eddies and the main-channel bed. We use a combination

Joseph E. Hazel Jr; David J. Topping; John C. Schmidt; Matt Kaplinski

2006-01-01

195

Geology on a Sand Budget  

NSDL National Science Digital Library

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--sand. Modeling geologic processes and features with sand is an effective way for teachers to promote student understanding of Earth science topics, quickly assess students' prior knowledge, and identify common misconceptions.

Kane, Jacqueline

2004-09-01

196

A physical chemical explanation for deterioration in the hot water processability of Athabasca oil sand due to aging  

SciTech Connect

The oxidation of sulphide minerals during storage of Athabasca oil sands cause solubilization of inorganic salts which affect recovery of bitumen during hot water extraction. DLVO and Ionizable Surface Group Model theories accurately predict that the level of soluble salts produced is sufficient to cause coagulation of the fine particles during the process which leads to a deterioration in froth quality and loss of bitumen recovery. The rate of aging is specific to each oil sand but storage of oil sands under an inert atmosphere in air-tight container at sub-zero temperatures will minimize oxidation.

Wallace, D.; Henry, D.; Takamura, K. (Alberta Research Council, Edmonton, AB (Canada). Oil Sands Research Dept.)

1989-01-01

197

Horizontal ethanol floods in clean, uniform, and layered sand packs under confined conditions  

NASA Astrophysics Data System (ADS)

Six ethanol floods were conducted in clean, uniform, and layered crystal silica sands to establish a baseline performance and sweep efficiency of ethanol flooding in clean sand packs under confined conditions. Flow experiments were conducted with horizontal darcy velocities of the order of 4 to 12 m d-1. At darcy velocities less than 5 m d-1 the time required for the propagating ethanol front to reach its stable configuration compared well with predictions based on a model of gravity segregation of miscible liquids in a no-flow domain. The stabilized angles of the advancing ethanol front in uniform fine sand packs varied between 45° and 77°, depending on the darcy velocity. Poor agreement was obtained between the measured inclination angles and predictions based on several previously published sharp interface models that exclude the effects of dispersion. However, the measured inclination angles compare well with the angles predicted by the method of Hawthorne [1960] when the method is modified to account for the peak viscosity of the ethanol-water system. Finally, in layered sand packs using coarse and fine sands, gravity override of the ethanol was greatly exaggerated because of anisotropy introduced by the layering.

Grubb, Dennis G.; Sitar, Nicholas

1999-11-01

198

Tar sands and oil shales  

Microsoft Academic Search

The worlds largest potential liquid-hydrocarbon reserves are not recoverable by ordinary oil-producing methods. These reserves are the Athabasca tar sands of northern Alberta in Canada and the Green River oil shales of Colorado, Utah, and Wyoming. The two deposits differ in their chemistry, physical state, and history. Both contain hydrocarbons that can be converted economically into petroleum products. Both occur

de Never

1966-01-01

199

Geology on a Sand Budget  

ERIC Educational Resources Information Center

Earth science teachers know how frustrating it can be to spend hundreds of dollars on three-dimensional (3-D) models of Earth's geologic features, to use the models for only a few class periods. To avoid emptying an already limited science budget, the author states that teachers can use a simple alternative to the expensive 3-D models--sand. She…

Kane, Jacqueline

2004-01-01

200

Sand and Water Table Play  

ERIC Educational Resources Information Center

The authors observed preschoolers engaged at the sand 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…

Wallace, Ann H.; White, Mary J.; Stone, Ryan

2010-01-01

201

V-2 at White Sands  

NASA Technical Reports Server (NTRS)

A V-2 rocket is hoisted into a static test facility at White Sands, New Mexico. The German engineers and scientists who developed the V-2 came to the United States at the end of World War II and continued rocket testing under the direction of the U. S. Army, launching more than sixty V-2s.

1947-01-01

202

Studies of Phlebotomine Sand Flies.  

National Technical Information Service (NTIS)

Studies of phlebotomine sand flies from Guatemala showed that 13 out of 25 total species have not been previously reported from that country. A review of these species is given here. It includes illustrations and a description of a new species. Other new ...

D. G. Young

1981-01-01

203

Technology Assessment of Intermittent Sand Filters.  

National Technical Information Service (NTIS)

Intermittent sand filtration of wastewater is not a new technology. Sand filters were often used by sewered communities around the turn of the century. However, as wastewater flows and land costs increased, they were replaced by mechanical treatment proce...

D. L. Anderson R. L. Siegrist R. J. Otis

1985-01-01

204

Loose sand habitat at the Mojave desert  

NSDL National Science Digital Library

Loose sand soil lacks moisture but contains adequate moisture and nutrients for drought tolerant plants. Loose sand soil is insufficient for animals to find or make shelter. Organisms find shade and shelter under the large shrubs.

Katie Hale (California State University, Fullerton;Student. Biological Sciences)

2007-01-06

205

Electrokinetic injection of ammonium and sulfate ions into sand and kaolinite beds  

SciTech Connect

Electrokinetic remediation is an emerging in-situ remediation technique that employs a low-level direct current (DC) across an electrode system inserted in soil to extract inorganic/organic species. The efficiency of electrokinetic injection of a cation (ammonium) from the anode and an anion (sulfate) from the cathode into a fine-grained sand bed and a kaolinite bed is investigated. Electrodes are placed in chambers across 80 cm of soil beds in a flume. The electrical conductivity of the kaolinite bed was 124.1 {+-} 6.6 {micro}S/cm approximately an order of magnitude higher than the fine sand bed while the hydraulic conductivity of the same was 2 {times} 10{sup {minus}7} cm/s about three orders of magnitude lower than the fine-grained sand bed. The electrical gradients of 1 V/cm or less constituted the predominant driving force for transport under constant current densities of 15 {micro}A/cm{sup 2} and 123 {micro}A/cm{sup 2} in the sand and kaolinite beds, respectively. An electrolyte conditioning scheme where the co-ions (hydroxide ion in the ammonium hydroxide used at the anode and the hydronium ion in the sulfuric acid used at the cathode) depolarized the electrode reactions maintained the pH value across the beds between 6.5 and 7.4. This novel conditioning scheme prevented formation and introduction of species formed by the electrode reactions and avoided unnecessary increase in the electrical conductivity in the electrolytes. Transport rates on the order of 8--20 cm/d were achieved for sulfate and ammonium ions in both the fine-grained sand bed and the kaolinite bed.

Acar, Y.B.; Rabbi, M.F.; Ozsu, E.E. [Louisiana State Univ., Baton Rouge, LA (United States)

1997-03-01

206

Washability of fine coal  

Microsoft Academic Search

The objectives of this study are: (1) to determine the theoretical beneficiation potential of US coals when pulverized down to 44 microns, (2) to determine the effects of fine grinding on the liberation of ash, pyritic sulfur, and other impurities, and (3) to assess the impact of their removal on oil and gas replacement, environmental regulations, and specification feedstocks for

Cavallaro

1984-01-01

207

FINE PARTICLE CHARGING DEVELOPMENT  

EPA Science Inventory

The report gives results of theoretical and experimental investigations into the changing of fine particles by unipolar ions in an electric field, and evaluation of a specially designed small pilot-scale (600-1000 acfm) precharging device. Following an extensive review of the lit...

208

Dewatering of fine coal  

SciTech Connect

Fine coal dewatering is one of the most pressing problem facing the coal cleaning industry. This project was undertaken with the objective of improving the dewatering process with surface chemical activation by primarily understanding the fundamental and process engineering aspects of vacuum filtration. Specific tasks for this project included -- development of an experimental apparatus and procedure to yield highly reproducible results and extensive data from each test, detailed experimental investigation of the dewatering characteristics of coal fines with and without the addition of flocculants and surfactants, and under different operating conditions, and finally identification and establishment of the physical limits of mechanical dewatering. Following are the significant conclusions from the study: Fineness and size distribution of the coal fines have the most significant influence on the coal dewatering process; usage of flocculants and surfactants is almost essential in reducing the cake moisture and in increasing the filter throughputs; based on the experimental data and the literature information, the existence of an asymptotic limit for filter cake moisture correlatable with a capillary number of the filter cake was identified. 66 refs., 23 figs., 7 tabs.

Sastry, K.V.S. (California Univ., Berkeley, CA (USA). Dept. of Materials Science and Mineral Engineering)

1991-01-01

209

The Valuation of the Alberta Oil Sands  

Microsoft Academic Search

The Alberta oil sands reserves represent a very valuable energy resource for Canadians. In 2007, Statistics Canada valued the oil sands at $342.1 billion, or 5 per cent Canada's total tangible wealth of $6.9 trillion. Given the oil sands' importance, it is essential to value them appropriately. In this report, we critically review the methods used by Statistics Canada in

Andrew Sharpe; Jean-François Arsenault; Alexander Murray; Sharon Qiao

2008-01-01

210

Foundry Sand Facts for Civil Engineers.  

National Technical Information Service (NTIS)

Metal foundries use large amounts of sand as part of the metal casting process. Foundries successfully recycle and reuse the sand many times in a foundry. When the sand can no longer be reused in the foundry, it is removed from the foundry and is termed f...

2004-01-01

211

Slow Sand Filtration: Influences of Selected Process Variables.  

National Technical Information Service (NTIS)

Biological activity within the sand bed had the strongest influence on removal efficiency of total coliform bacteria by slow sand filtration, as determined by six pilot filters. Temperature, sand bed depth, and sand size also had a strong influecee.

W. D. Bellamy D. W. Hendricks G. S. Logsdon

1985-01-01

212

NEXAFS microscopy studies of the association of hydrocarbon thin films with fine clay particles  

Microsoft Academic Search

The nature of organic species associated with clay minerals plays a significant role in several processes, from hydrocarbon recovery in oil sands to contaminated soil remediation and water treatment. In this work, we address the use of scanning transmission X-ray microscopy (STXM) in conjunction with near edge X-ray absorption fine structure (NEXAFS) spectroscopy to study the microstructure and chemistry of

Danielle Covelli; Daniel Hernández-Cruz; Brian M. Haines; Vincente Munoz; Oladipo Omotoso; Randy Mikula; Stephen Urquhart

2009-01-01

213

Wood dust particle and mass concentrations and filtration efficiency in sanding of wood materials.  

PubMed

The importance of fine particles has become apparent as the knowledge of their effects on health has increased. Fine particle concentrations have been published for outside air, plasma arc cutting, welding, and grinding, but little data exists for the woodworking industry. Sanding was evaluated as the producer of the woodworking industry's finest particles, and was selected as the target study. The number of dust particles in different particle size classes and the mass concentrations were measured in the following environments: workplace air during sanding in plywood production and in the inlet and return air; in the dust emission chamber; and in filter testing. The numbers of fine particles were low, less than 10(4) particles/cm(3) (10(7) particles/L). They were much lower than typical number concentrations near 10(6) particles/cm(3) measured in plasma arc cutting, grinding, and welding. Ultrafine particles in the size class less than 100 nm were found during sanding of MDF (medium density fiberboard) sheets. When the cleaned air is returned to the working areas, the dust content in extraction systems must be monitored continuously. One way to monitor the dust content in the return air is to use an after-filter and measure pressure drop across the filter to indicate leaks in the air-cleaning system. The best after-filtration materials provided a clear increase in pressure drop across the filter in the loading of the filter. The best after-filtration materials proved to be quite effective also for fine particles. The best mass removal efficiencies for fine particles around 0.3 mum were over 80% for some filter materials loaded with sanding wood dust. PMID:19065389

Welling, Irma; Lehtimäki, Matti; Rautio, Sari; Lähde, Tero; Enbom, Seppo; Hynynen, Pasi; Hämeri, Kaarle

2009-02-01

214

Sulfidization of Witwatersrand black sands: From enigma to myth  

SciTech Connect

Reassessment of the nature and distribution of iron-titanium oxide minerals vs. pyrite in several South African Archean arenaceous sequences and conglomerates shows that in rocks of the Swaziland, Pongola, and Witwatersrand Supergroups, (1) pyrite of allogenic and/or authigenic origin is the predominant heavy mineral; (2) iron-titanium oxides generally take the form of very fine grained, dispersed retile-leucoxene replacements after earlier black-sand minerals; (3) iron-titanium oxides constitute 1%-6% of the total heavy minerals; and (4) the phenomenon of sulfidization of iron-titanium oxide minerals is evident only on a very local scale. Exceptions to points 1 and 3 occur in conglomerates of the Dominion Group, which were derived from a largely pegmatitic terrain. The lack of macroscopically visible iron-titanium oxide minerals in the Witwatersrand conglomerates is a result of a combination of two factors. First, recycling of older sedimentary material was critical to the genesis of the conglomerates; older sedimentary material was critical to the genesis of the conglomerates; about 60% of the source area consisted of arenaceous sequences. Iron-titanium mineral grains from this source had been altered to rutile-leucoxene prior to erosion, and thus did not contribute fresh iron-titanium minerals to the conglomerates. Second, those minerals derived from the remaining 40% of the source area were altered and decomposed to rutile-leucoxene in the Witwatersrand conglomerates. Furthermore, much of the resulting finely dispersed material helped to form brannerite, an important titanium sink. There is no need to invoke widespread sulfidization of black sands to sands to account for the supposed lack of iron-titanium minerals and abundance of pyrite in the Witwatersrand conglomerates and ores.

Reimer, T.O. (Bernhard-May-Strasse, Wiesbaden-Biebrich (Germany, F.R.)); Mossman, D.J. (Mount Allison Univ., Sackville, New Brunswick (Canada))

1990-05-01

215

Proppant selection for fracturing and sand control  

SciTech Connect

Starting with definitions of gravel, sand and proppants, this article proceeds to discuss the basic design dilemma of selecting proppant size to achieve the optimum permeability of larger particles vs. higher strength and sand screening ability of smaller sizes. Equations for preventing sand invasion by velocity control are introduced and tables of data give engineers actual design information; tips on table use are included. Hydraulic frac/gravel pack treatments are accepted means of obtaining high well productivity and sand control. A one-step, tip-screenout efficiently creates a short fracture through near-wellbore formation damage and packs the screen/casing annulus to prevent sand production.

Sparlin, D.D.; Hagen, R.W. Jr. (International Completion Consultants Inc., Houston, TX (United States))

1995-01-01

216

Size and composition of airborne particles from pavement wear, tires, and traction sanding.  

PubMed

Mineral matter is an important component of airborne particles in urban areas. In northern cities of the world, mineral matter dominates PM10 during spring because of enhanced road abrasion caused by the use of antiskid methods, including studded tires and traction sanding. In this study, factors that affect formation of abrasion components of springtime road dust were assessed. Effects of traction sanding and tires on concentrations, mass size distribution, and composition of the particles were studied in a test facility. Lowest particle concentrations were observed in tests without traction sanding. The concentrations increased when traction sand was introduced and continued to increase as a function of the amount of aggregate dispersed. Emissions were additionally affected by type of tire, properties of traction sand aggregate, and driving speed. Aggregates with high fragmentation resistance and coarse grain size distribution had the lowest emissions. Over 90% of PM10 was mineral particles. Mineralogy of the dust and source apportionment showed that they originated from both traction sand and pavement aggregates. The remaining portion was mostly carbonaceous and originated from tires and road bitumen. Mass size distributions were dominated by coarse particles. Contribution of fine and submicron size ranges were approximately 15 and 10% in PM10, respectively. PMID:15757329

Kupiainen, Kaarle J; Tervahattu, Heikki; Räisänen, Mika; Mäkelä, Timo; Aurela, Minna; Hillamo, Risto

2005-02-01

217

Quasi-static compression of granular materials (sand) at high pressures (~3 GPA)  

NASA Astrophysics Data System (ADS)

This investigation presents the results on the static behavior of confined sand (from Eglin Air Force Base) subjected to axial compressive stresses up to 3 GPa. A self-aligning compression fixture was developed to statically compress sand specimen in a cylindrical steel confinement using tungsten carbide pins. A strain gage was mounted on the confining cylinder to measure the circumferential strain. Using axial stress, axial strain, and hoop strain the multi axial behavior of the confined sand is investigated. Compressive tests were conducted up to axial strains of 35%. The static response of the dry sand was tested at four different initial densities, namely, 1.55, 1.60, 1.65, and 1.75 g/cm 3. Effects of particle size, primarily classified as coarse and fine, were investigated. The effect of moisture was also investigated at four different degrees of saturation, namely, 0%, 20%, 40%, and 100%. The dense sand provided a much stiffer response than the loosely packed ones. The coarse sand grains showed significant crushing of particles followed by compaction of the powdered grains.

Subramanian, Vijay Krishnan

218

Assessment of Constitutive and Stability Behavior of Sands Under Plane Strain Condition  

NASA Technical Reports Server (NTRS)

A series of biaxial (plane strain) experiments were conducted on three sands under low (15 kPa) and high (100 kPa) confining pressure conditions to investigate the effects of specimen density, confining pressure, and sand grains size and shape on the constitutive and stability behavior of granular materials. The three sands used in the experiments were fine, medium, and coarse-grained uniform silica sands with rounded, sub-angular, and angular grains, respectively. Specimen deformation was readily monitored and analyzed with the help of a grid pattern imprinted on the latex membrane. The overall stress-strain behavior is strongly dependent on the specimen density, confining pressure, sand grain texture, and the resulting failure mode(s). That became evident in different degrees of softening responses at various axial strains. The relationship between the constitutive behavior and the specimens' modes of instability is presented. The failure in all specimens was characterized by two distinct and opposite shear bands. It was found that the measured dilatancy angles increase as the sand grains' angularity and size increase. The measured shear band inclination angles are also presented and compared with classical Coulomb and Roscoe solutions.

Alshibli, Khalid A.; Sture, Stein

2000-01-01

219

Ozonation of diesel-fuel contaminated sand and the implications for remediation end-points.  

PubMed

In this study, we investigate specifically the influence of soil grain size and water content on the degradation of n-alkane fractions and the formation of aldehydes and carboxylic acid during ozonation. 15g of quartz sand spiked with diesel (25gkg(-1)) were exposed to ozone for 20h at concentrations of 10, 30 and 50mgL(-1), respectively. Results indicated that ozonation of the n-alkanes in fine grain size sand (0.15-0.25mm) was 1.2 times faster than coarse sand due to higher surface contact area between O3 and sand particles. Soil moisture below 18% w/w did not influence the ozonation efficiency. In contrast the ozonation led to an increase of acidity of the sand samples (pH=3.0) after 20h treatment. This was due to the formation of carboxylic acid. Formaldehyde, one of the key by-products of ozonation, was always <13mgkg(-1) after the treatment which is below the industrial soil clean-up target level. While the aldehydes and carboxylic acid further reacted with O3 and their ozonation rate were slower than those of the alkanes suggesting that the hydroxylated by-products accumulated in the sand during the process. Overall the findings demonstrated that not only the alkanes but also aldehydes and carboxylic acid should be considered when defining remediation end-points. PMID:24873709

Li, Xingang; Cao, Xingtao; Wu, Guozhong; Temple, Tracey; Coulon, Frédéric; Sui, Hong

2014-08-01

220

Sedimentary structures and textures of Rio Orinoco channel sands, Venezuela and Colombia  

USGS Publications Warehouse

Most sedimentary structures represented in sand bodies of the Rio Orinoco are tabular-planar cross-strata which, together with some wedge-planar cross-strata, are the products of sand-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 beds 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 sand (? - ? millimeter) as determined by screen analyses. Many samples, however, also contain moderate quantities of coarse or very coarse sand. Eolian dunes on top of the sand-wave deposits are dominantly fine grained. The river channel sands were determined to be largely moderately well sorted, although in some places they were mostly well sorted, and in others, mostly moderately sorted.

McKee, Edwin Dinwiddie

1989-01-01

221

Foundry sands as low-cost adsorbent material for Cr (VI) removal.  

PubMed

The potential of foundry sands, industrial waste from the iron foundry industry, was evaluated for the removal of Cr (VI) using discontinuous assays. Chemical foundry sands are composed of fine silica sand, furanic resins as binder, chemical catalyst and residual iron particles. The influence ofpH, agitation rate and metal concentration on the removal process was investigated. Kinetic and equilibrium tests were conducted to determine Cr (VI) removal from aqueous solutions at a temperature range of 25-55 degrees C. Cr (VI) removal of 40-100% for a range of pH 6-1.6 was obtained. This removal was attributed to the presence of a large number of protonated silanol and aluminol groups. Cr (VI) adsorption in foundry sands follows a pseudo-second-order kinetic reaction (Ho model, r2 > 0.999) reaching kinetic constants of 0.341, 0.551, 0.775 and 0.920 g/mg h at 25, 35, 45 and 55 degrees C, respectively. The adsorption data were fitted to the Langmuir adsorption isotherm model (r > 0.99) obtaining adsorption capacities (q(max)) of 1.99, 2.40, 2.50, and 3.14 mg Cr (VI)/g sand at 25, 35, 45 and 55 degrees C, respectively. Calculated Gibbs free energy change (deltaG0), adsorption energy (E) and activation energy (E(a)) values indicate that a physisorption mechanism governs Cr (VI) adsorption process in foundry sands. PMID:24191460

Campos, I; Alvarez, J A; Villar, P; Pascual, A; Herrero, L

2013-01-01

222

Anatomy of a shoreface sand ridge revisited using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf  

NASA Astrophysics Data System (ADS)

Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf ˜5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

Robinson, Marci M.; McBride, Randolph A.

2008-10-01

223

Anatomy of a shoreface sand ridge revisited using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf  

USGS Publications Warehouse

Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf ???5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

Robinson, M. M.; McBride, R. A.

2008-01-01

224

Anatomy of a shoreface sand ridge revisted using foraminifera: False Cape Shoals, Virginia/North Carolina inner shelf  

USGS Publications Warehouse

Certain details regarding the origin and evolution of shelf sand ridges remain elusive. Knowledge of their internal stratigraphy and microfossil distribution is necessary to define the origin and to determine the processes that modify sand ridges. Fourteen vibracores from False Cape Shoal A, a well-developed shoreface-attached sand ridge on the Virginia/North Carolina inner continental shelf, were examined to document the internal stratigraphy and benthic foraminiferal assemblages, as well as to reconstruct the depositional environments recorded in down-core sediments. Seven sedimentary and foraminiferal facies correspond to the following stratigraphic units: fossiliferous silt, barren sand, clay to sandy clay, laminated and bioturbated sand, poorly sorted massive sand, fine clean sand, and poorly sorted clay to gravel. The units represent a Pleistocene estuary and shoreface, a Holocene estuary, ebb tidal delta, modern shelf, modern shoreface, and swale fill, respectively. The succession of depositional environments reflects a Pleistocene sea-level highstand and subsequent regression followed by the Holocene transgression in which barrier island/spit systems formed along the Virginia/North Carolina inner shelf not, vert, ~5.2 ka and migrated landward and an ebb tidal delta that was deposited, reworked, and covered by shelf sand.

Robinson, Marci M.; McBride, Randolph A.

2008-01-01

225

Sand dunes as migrating strings.  

PubMed

We develop a reduced complexity model for three-dimensional sand dunes, based on a simplified description of the longitudinal and lateral sand transport. The spatiotemporal evolution of a dune migrating over a nonerodible bed under unidirectional wind is reduced to the dynamics of its crest line, providing a simple framework for the investigation of three-dimensional dunes, such as barchan and transverse dunes. Within this model, we derive analytical solutions for barchan dunes and investigate the stability of a rectilinear transverse dune against lateral fluctuations. We show, in particular, that the latter is unstable only if the lateral transport on the dune slip face prevails over that on the upwind face. We also predict the wavelength and the characteristic time that control the subsequent evolution of an unstable transverse dune into a wavy ridge and the ultimate fragmentation into barchan dunes. PMID:23767529

Guignier, L; Niiya, H; Nishimori, H; Lague, D; Valance, A

2013-05-01

226

Update on federal tight sands incentive policies  

SciTech Connect

Recognizing the great potential of increased domestic tight sands production in reducing imports of foreign energy, several branches of the federal government have initiated policies to encourage development of this resource. However, these policies have been slow in formulation, and some are potentially in conflict with each other. Two characteristics of tight sands gas have led to it being singled out for special regulatory treatment. Production from tight sands usually requires the implementation of expensive enhanced recovery techniques, such as hydraulic fracturing, to make development commercially feasible. This has limited production from tight sands to approximately 1 tcf annually. Second, tight sands gas resources have the potential for doubling domestic, commercially recoverable natural gas reserves. This study discusses the current status of pricing mechanisms affecting tight sands and emerging trends for tight sands incentives.

Buch, L.

1980-11-01

227

CHARACTERIZATION OF FINE PARTICULATE MATTER  

EPA Science Inventory

Size distribution data processing and fitting Ultrafine, very fine and fine PM were collected nearly continuously from December 2000 through March 2003 at a Washington State Department of Ecology site on Beacon Hill in Seattle. Particle size distributio...

228

Thermal Properties of oil sand  

NASA Astrophysics Data System (ADS)

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 sand samples from Athabasca, Canada, using a transient thermal property measurement instrument. Thermal conductivity of 43 oil sand 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 sand 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 sand.

LEE, Y.; Lee, H.; Kwon, Y.; Kim, J.

2013-12-01

229

Thermal recovery from tar sands  

SciTech Connect

On the basis of the progress made in developing improved technology for recovery of bitumen from tar sands, it is logical to assume that as the world's supply of light and heavy oil is depleted, production of synthetic oil from the bitumen resources in tar sands will accelerate. As most of the known deposits of tar sands were discovered by accident, there is reason to believe that a worldwide exploration program based on sound geological principles will discover much more of this material. The long lead times required to turn this massive resource into acceptable alternative refinery feedstock at a reasonable price make it imperative that we vigorously pursue the development of recovery technology at this time if we are to avoid shortages of liquid fuel early in the next century. There is no question that the light-crude-oil substitute developed from this resource will be more expensive than the conventional light and heavy crudes being used today. However, there is reason to believe that the differential in costs will narrow as the search for new sources of light oil swings to deeper targets in more remote and hostile environments, such as the continental shelves and arctic islands, and more expensive enhancedrecovery techniques are used to recover the oil now left behind in deep depleted light- and heavy-oil reservoirs.

Carrigy, M.A.

1983-12-01

230

EPA fines increase, Exxon cited  

SciTech Connect

Early this month the Environmental Protection Agency fined Exxon`s Bayway, NJ operation $178,000 for violations uncovered during a {open_quotes}multimedia{close_quotes} inspection. The fine reflects big increases in environmental penalties over the past few years that are expected to continue. Since fiscal 1989, the civil and criminal fines EPA has collected have reached more than $300 million.

Kirschner, E.

1992-12-16

231

Two-region flow and decreased sorption of uranium (VI) during transport in hanford groundwater and unsaturated sands  

Microsoft Academic Search

Uranium, U(VI), sorption and transport in unsaturated coarse- and fine- textured sands were evaluated using a centrifuge method; batch incubation and saturated column experiments were conducted to isolate the effect of flow from that of water content. At higher water contents (?66% saturation), decreases in U(VI) sorption were due to rate limitations. These breakthrough curves (BTCs) were well characterized with

A. P. Gamerdinger; D. I. Kaplan; D. M. Wellman; R. J. Serne

2001-01-01

232

Identifying production zones with NUV\\/VIS\\/NIR spectra: Examples from the Caddo Limestone and Strawn Sand  

Microsoft Academic Search

Production zones in three conventional cores - two from wells in the Caddo Limestone, Breckenridge Field and one from the Strawn Sand, Hull-Silk Field - were analyzed with a total reflectance spectrophotometer. Samples were prepared at one foot intervals through production and non-production zones by grinding 0.5 grams of rock to a fine powder, making the powder into a slurry

B. C. Deaton; W. L. Balsam

1993-01-01

233

The chemistry of Saudi Arabian sand - A deposition problem on helicopter turbine airfoils  

NASA Astrophysics Data System (ADS)

Operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz, (Ca,Mg)CO3 dolomite, CaCO3 calcite, and occasionally NaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 5 mm thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of CaSO4.

Smialek, James L.; Archer, Frances A.; Garlick, Ralph G.

234

The chemistry of Saudi Arabian sand: A deposition problem on helicopter turbine airfoils  

NASA Technical Reports Server (NTRS)

Recent operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz (Ca,Mg) CO3 dolomite, CaCO3 calcite, and occasionally CaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 0.25 in. thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of GaSO4.

Smialek, James L.

1991-01-01

235

The Chemistry of Saudi Arabian Sand - A Deposition Problem on Helicopter Turbine Airfoils  

NASA Technical Reports Server (NTRS)

Operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz, (Ca,Mg)CO3 dolomite, CaCO3 calcite, and occasionally NaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 5 mm thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of CaSO4.

Smialek, James L.; Archer, Frances A.; Garlick, Ralph G.

1992-01-01

236

[Environmental toxicity of waste foundry sand].  

PubMed

The metal leaching characteristics and volatile organic compounds (VOCs) of five different types of waste foundry sands 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 sands. The results showed that due to the different metals poured and casting materials used to make the sand molds, there was significant difference among the five waste foundry sands in the compositions and concentrations of metal and organic pollutants. The concentrations of Fe in the leachates of iron and steel casting waste foundry sand 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 sand exceeded the standard. The five waste foundry sands 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 sands may inhibit the soil microbial activity, whereas organics in the sands may slightly promote the microbial activity. The results of this study indicated that the waste foundry sands may pose considerable threat to the environment when improperly disposed. PMID:23745431

Zhang, Hai-Feng; Wang, Yu-Jue; Wang, Jin-Lin; Huang, Tian-You; Xiong, Ying

2013-03-01

237

Fine needle aspiration cytology.  

PubMed Central

Fine needle aspiration cytology is an inexpensive, atraumatic technique for the diagnosis of disease sites. This paper describes the technique and illustrates how it may be applied to the management of tumours throughout the body. The limitations of the method, the dangers of false positive reports, and the inevitability of false negative diagnoses are emphasised. In a clinical context the method has much to offer by saving patients from inappropriate operations and investigations and allowing surgeons to plan quickly and more rationally. It is an economically valuable technique and deserves greater recognition. Images

Lever, J V; Trott, P A; Webb, A J

1985-01-01

238

Additive Surface Complexation Modeling of Uranium(VI) Adsorption onto Quartz-Sand Dominated Sediments.  

PubMed

Many aquifers contaminated by U(VI)-containing acidic plumes are composed predominantly of quartz-sand sediments. The F-Area of the Savannah River Site (SRS) in South Carolina (USA) is an example. To predict U(VI) mobility and natural attenuation, we conducted U(VI) adsorption experiments using the F-Area plume sediments and reference quartz, goethite, and kaolinite. The sediments are composed of ?96% quartz-sand and 3-4% fine fractions of kaolinite and goethite. We developed a new humic acid adsorption method for determining the relative surface area abundances of goethite and kaolinite in the fine fractions. This method is expected to be applicable to many other binary mineral pairs, and allows successful application of the component additivity (CA) approach based surface complexation modeling (SCM) at the SRS F-Area and other similar aquifers. Our experimental results indicate that quartz has stronger U(VI) adsorption ability per unit surface area than goethite and kaolinite at pH ? 4.0. Our modeling results indicate that the binary (goethite/kaolinite) CA-SCM under-predicts U(VI) adsorption to the quartz-sand dominated sediments at pH ? 4.0. The new ternary (quartz/goethite/kaolinite) CA-SCM provides excellent predictions. The contributions of quartz-sand, kaolinite, and goethite to U(VI) adsorption and the potential influences of dissolved Al, Si, and Fe are also discussed. PMID:24865372

Dong, Wenming; Wan, Jiamin

2014-06-17

239

Morris. E. Fine symposium  

SciTech Connect

Professor Morris E. Fine is a pioneer in teaching the unifying concepts underlying all classes of materials: metals, ceramics, polymers, and electronic materials. He is a founder and the guiding genius of the first materials science department in the world. His research career at Northwestern University has spanned a broad range of topics, from physical chemistry to mechanical behavior, and includes studies on metals and alloys, ceramics, and composite materials. A symposium to recognize the many outstanding contributions by Professor Fine to the development of materials science as a discipline was organized on behalf of the TMS-ASM Committees of Mechanical Metallurgy, Flow and Fracture, and Structural Materials. This symposium was held in Detroit, Michigan, on 8-11 October in conjunction with the 1990 TMS Fall Meeting and Materials Week. Academic, government, and industrial speakers from around the globe gathered to present the latest concepts and experimental results on topics ranging from advanced materials to fundamental principles governing materials behavior. The papers were divided into seven sessions: Physical Metallurgy, Ferrous Structural Materials, Metal Matrix Composites, Microstructural Evolution, Engineering Materials, Fatigue and Fracture, and Flow and Fracture in Non-Ferrous Materials.

Liaw, P.K. (Westinghouse Science and Technology Center, Pittsburgh, PA (US)); Marcus, H.L. (Univ. of Texas at Austin, Materials Science and Engineering Programs, Austin, TX (US)); Weertman, J.R. (Dept. of Materials Science and Engineering, Northwestern Univ., Evanston, IL (US)); Santer, J.S. (Packer Engineering, Naperville, IL (US))

1990-01-01

240

Northwest Plume Groundwater System Green-sand Media Removal and Waste Packaging Paducah Gaseous Diffusion Plant, Paducah, Kentucky  

SciTech Connect

The Northwest Plume Groundwater System (NWPGS) was temporarily shut down due to high differential pressures across the green-sand filters. Increased levels of suspended solids were introduced into the system from monitoring well development water, equipment decontamination water, and secondary containment water. These waters were treated for suspended solids through a groundwater pretreatment system but were suspected of causing the high differential pressures in the green-sand filters. Prior to the system being shutdown, the NWPGS had been experiencing increasingly shorter run times between filter backwashes indicating that the normal backwash cycle was not adequately removing the fines. This condition led to the removal and replacement of green-sand media from two filter vessels. Discussions include problems with the removal process, waste packaging specifications, requirements for the disposition of green-sand media, and lessons learned. (authors)

Troutman, M.T.; Richards, C.J.; Tarantino, J.J. [CDM Federal Programs Corporation, 325 Kentucky Avenue, Kevil, KY 42053 (United States)

2006-07-01

241

Direct laser sintering of a silica sand  

Microsoft Academic Search

As an application study of rapid prototyping, commercially available silica sand was successfully direct-laser-sintered in a self-developed high-temperature laser sintering equipment. The mechanism of powder-state sand becoming a solid state block during the laser sintering process was disclosed by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis on sand particles and sintered samples. The effect of process parameters

Y. Tang; J. Y. H. Fuh; H. T. Loh; Y. S. Wong; L. Lu

2003-01-01

242

Vacuum Head Removes Sanding Dust: Tool removes dust as it sands.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A modified sanding block scoops up the dust it creates and delivers it to a vacuum exhaust tube. The block sands, shapes, or polishes without introducing contaminati...

1982-01-01

243

A branching process model for sand avalanches  

SciTech Connect

An analytically solvable model for sand avalanches of noninteracting grains of sand, based on the Chapman-Kolmogorov equations, is presented. For a single avalanche, distributions of lifetimes, sizes of overflows and avalanches, and correlation functions are calculated. Some of these are exponentials, some are power laws. Spatially homogeneous distributions of avalanches are also studied. Computer simulations of avalanches of interacting grains of sand are compared to the solutions to the Chapman-Kolmogorov equations. It is found that within the range of parameters explored in the simulation, the approximation of noninteracting grains of sand is a good one. 20 refs., 4 figs.

Garcia-Pelayo, R.; Salazar, I.; Schieve, W.C. (Univ. of Texas, Austin (United States))

1993-07-01

244

The Effect of Preferential Flow on Colloidal Transport in Unsaturated Heterogeneous Sand  

NASA Astrophysics Data System (ADS)

Transport of colloids may be greatly enhanced by the presence of preferential flow pathways (PF). The impact of PF on the overall colloid transport was investigated in unsaturated heterogeneous sand under steady-state flow conditions. The experiments were conducted in a 30 cm column, with 11.5 cm internal diameter. Two types of acid-cleaned sand were used to pack the column: coarse (d50 = 1.2 mm) and fine (d50 = 0.36 mm). Heterogeneity created by three continuous bodies of fine sand (within a column of coarse sand) comprised 3.7% of the total sand volume. Water content and pressure head in the coarse sand were monitored with three pairs of TDR probes and tensiometers, respectively, evenly spaced along the column length. Experiments were performed under three different flow rates applied at the top of the column using a rain simulator. Negative pressure (-8, -6, and -5.5 cm corresponding to flow rates of 0.1, 0.2 and 0.4 cm/min, respectively) was maintained at the bottom of the column to produce a constant water content profile (11, 12 and 14% by volume, respectively) in coarse sand. Numerical simulations that were carried out using a double porosity, double permeability model and the Hydrus-2D model, showed higher water content, hydraulic conductivity and, as a result, greater flux in fine sand compared with the bulk of coarse sand. Three sizes of fluorescent latex microspheres were used: 1, 0.2 and 0.02 ?m in a mixture with conservative tracers (LiBr). A pulse injection of one water column volume (corresponding to a prescribed water content) of solution was followed by flushing with artificial rainwater. The main features of the breakthrough curves (BTCs) obtained from the heterogeneously packed column were earlier arrival of tracer concentration front (as early as 0.25 water column volume) and tailing. Colloid arrival occurred at effectively the same time as that of conservative tracers, with the exception of the smallest colloids (0.02 ?m), which arrived with some delay. The BTCs of colloids also exhibited considerable tailing. A decrease in flow rate from 0.2 to 0.1 cm/min caused a decrease of 44, 40 and 58% in mass recovery for particles of 1, 0.2 and 0.02 ?m, respectively. Comparable experiments carried out in the homogeneously packed column showed a two/three-fold increase in arrival time, and no tailing was observed in the fine sand column. Early arrival as well as small-particle retention observed in experiments with heterogeneous sand may indicate high mass exchange between the bulk and the preferential paths. Numerical analysis with the double porosity, double permeability model revealed a high influence of the mass exchange coefficient on arrival time and shape of BTCs.

Mishurov, M.; Yakirevich, A.; Weisbrod, N.; Kuznetsov, M.

2006-12-01

245

Cell abundance and microbial community composition along a complete oil sand mining and reclamation process  

NASA Astrophysics Data System (ADS)

Hydrocarbons constitute an important energy source for microbes but can also be of environmental concern. Microbial activity causes hydrocarbon degradation and thereby loss of economical value, but also helps to remove hydrocarbons from the environment. The present study characterizes the abundance of microbes along the oil sand mining process in Alberta, Canada, as a first approach to assess the impact of mining and oil extraction on the microbial population. After mining the oil is extracted from the sediment by a hot-water extraction (50-60°C), resulting in three major fractions: crude oil, tailings sand and fine tailings. The tailings sand is used as substratum for newly developing soils on the reclamation areas. The very liquid fine tailings still have a TOC content of about 4.3% and are pumped into tailings ponds, where they need up to three decades to settle and solidify. After deposition, these mature fine tailings (MFTs) are enriched in organics (TOC content between 9.6 and 16.8%) and dredged out of the ponds and put on dumps for several years for dewatering. Finally they are brought out onto the reclamation sites and deposited below the sand layer. Cells were extracted from oily sediments according to the protocol of Lappé and Kallmeyer (2011), stained with SYBR Green I and counted by fluorescence microscopy. Cell abundance in the unprocessed oil sand is around 1.6 x 107 cells cm-3. After processing the fresh fine tailings still contain around 1.6 x 107 cells cm-3. Cell counts in the processed MFTs are 5.8 x 107 cells cm-3, whereas in the sand used as substratum for newly developing soils, they are twice as high (1.4 x 108). In root-bearing horizons, cell counts reach 1.1 x 109 cell cm-3. Cell numbers calculated from cultivation experiments are in the same range. Higher cell counts in the tailings sand are probably due to a higher nitrogen supply through the addition of a 35 cm top layer of a peat-mineral mix. In the sand nitrate concentrations are high (~0.37 mmol/L), whereas in the MFTs nitrate concentrations are much lower (~0.04 mmol/L). In some MFT samples sulphate appears to be the most abundant electron acceptor (up to 94 mmol/L) but no hydrogen sulphide could be detected. High cell counts in root-bearing layers might be related to a supply with otherwise unavailable nutrients, especially phosphorus. Another plausible explanation is that the cells are brought in the sand with the peat-mineral mix, because it seems that the mix contains a significant amount of roots. Samples with low amounts or no roots showed lower cell abundances. Sand and MFTs also differ in the microbial community composition. Molecular analysis of bacterial isolates of samples with different oil content show that ?-Proteobacteria dominate the cultivable bacterial population in substrates with a high residual content of oil, whereas in the low oil content sand they play a minor role. The data of corresponding metagenomic analyses confirm these results. In MFTs ?-Proteobacteria make up about 80% of the total bacterial population. The surprisingly stable cell abundance indicates that microbial processes take place throughout the entire production process. Rising cell numbers in root-bearing horizons show that a plant cover fosters microbial abundance and diversity, helping to restore full ecosystem functionality.

Lappé, M.; Schneider, B.; Kallmeyer, J.

2012-12-01

246

Effect of interparticle adhesion forces on elutriation of fine powders from a fluidized bed of a binary particle mixture  

Microsoft Academic Search

The elutriation of fine powders from a fluidized bed of a fine-coarse particle mixture was investigated in a transparent column with a diameter of 7.1 cm and a height of 102 cm at superficial gas velocities from 0.3 to 0.9 m\\/s. In the experiments, a silic sand (group B particle) was used as the coarse particles, whereas several kinds of

Xiaoxun Ma; Kunio Kato

1998-01-01

247

Trends in Gypsiferous Aerosol Downwind of White Sands, New Mexico  

NASA Astrophysics Data System (ADS)

White Sands is a known 'hotspot' of dust emissions in southwestern North America where an active gypsum dunefield abuts erodible playa sediments. Aerosols entrained from White Sands are sometimes visible on satellite images as distinct, light-colored plumes crossing the Sacramento Mountains to the northeast. The U.S. Forest Service operates an aerosol sampler at White Mountain in the lee of the Sacramento range as part of the IMPROVE network (Interagency Monitoring of PROtected Visual Environments). In recent years a spring pulse of sulfate aerosol has appeared at White Mountain, eclipsing the regional summer peak attributed to atmospheric reactions of sulfur dioxide emissions. A significant fraction of this spring sulfate is contributed by gypsum and other salts from White Sands, with clearly increased concentrations of calcium, strontium, and chloride. The increase in these species coincides with a drought following a period of above-average precipitation. White Sands and White Mountain thus provide an unusually well-defined natural laboratory: a climatically sensitive dust source that is both well characterized and chemically distinct from its surroundings, with a signature that remains identifiably distinct at a long-term observatory ~100 km downwind. This paper examines the routine PM2.5 (fine-particle, Dp < 2.5 um) composition data available from White Mountain and other regional IMPROVE sites (e.g. Bosque del Apache), supplemented by some elemental analysis of collocated PM10 samples. The ambient data are compared with chemical analyses of surface samples from White Sands, bulk dry dustfall and soil surface composition at White Mountain, satellite observations of dust plumes, and available meteorological records. Together, the observations document significant, episodic aeolian transport of gypsum and other salts across the Sacramento Mountains. Figure 1. Left: Monthly average concentrations of every-third-day 24h samples. Top right: MODIS image, 2/28/2012, http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=77294). Bottom right: Correlation (r) matrix for 2011 daily elemental data from White Mountain (n = 105).

White, W. H.; Trzepla, K.; Yatkin, S.; Gill, T. E.; Jin, L.

2013-12-01

248

Influence of fly ash fineness and shape on the porosity and permeability of blended cement pastes  

NASA Astrophysics Data System (ADS)

The effects of the fineness and shape of fly ash on the porosity and air permeability of cement pastes were investigated. Pulverized coal combustion (PCC) fly ash and fluidized bed coal combustion (FBC) fly ash classified into three different finenesses were used. River sand with particle size distribution similar to that of fly ash was also used for comparison. Portland cement was replaced with fly ash and ground sand at the dosages of 0, 20wt%, and 40wt%. A water-to-binder ratio (w/b) of 0.35 was used throughout the experiment. The results show that the porosity and air permeability of the pastes are influenced by the shape, fineness, and replacement level of fly ash. The porosity and air permeability of FBC fly ash pastes are higher than those of PCC fly ash pastes. This is due to the higher irregular shape and surface of FBC fly ash compared to the spherical shape and relatively smooth surface of PCC fly ash. The porosity increases with the increase in fly ash replacement level and decreases with the increase in its fineness. The permeability of PCC fly ash pastes decreases with the increase in replacement level and fineness, while for FBC fly ash, the permeability increases with the increase in replacement level. Decreases in porosity and permeability are due to a combined effect of the packing of fine particles and the reaction of fly ash.

Sinsiri, Theerawat; Chindaprasirt, Prinya; Jaturapitakkul, Chai

2010-12-01

249

Modelling the effect of fine sediment on salmonid spawning habitat  

NASA Astrophysics Data System (ADS)

Diffuse fine sediment delivery to rivers is recognised as a widespread problem in the UK. Furthermore, projections suggest that sediment pressures may increase in the future due to both climate change and land use changes. This fine sediment infiltrates into the bed and clogs up salmonid spawning gravels. Fine sediment has been found to reduce survival rates of salmonid eggs in both field and laboratory experiments, with the main hypotheses used to explain this being (a) fine sediment reduces gravel permeability and intra-gravel flow velocities; (b) intra-gravel O2 concentrations decrease due to reduced supply and increased consumption by organic sediments; and (c) clay particles block the exchange of O2 across the egg membrane. The SIDO (Sediment Intrusion and Dissolved Oxygen)-UK model is a physically based numerical model which stimulates the effect of fine sediment intrusion on the abiotic characteristics of the salmonid redd, along with the consequences for egg development and survival. The first 2 hypotheses above are represented, while the third is not yet included. Field observations from the River Ithon, Wales, have been used to calibrate the model using sediment accumulation data. The model was then used to assess the impact of varying sediment inputs upon the sediment intrusion rates, abiotic redd characteristics and fish egg survival rates. Results indicate that egg survival is highly sensitive to the discharge and the suspended sediment concentrations, particularly to changes in the supply rate of sand particles, rather than silt and clay. This can be explained by the increased likelihood of blocking of intra-gravel pores by larger sand particles, which reduce intra-gravel flow velocities and the supply of oxygen rich water. A doubling of the sand concentration results in a 51% increase in red infilling, which causes a 24% reduction in the average intra-gravel flow velocity. A corresponding 20% decrease of the average O2 concentration is evident which is a function of reduced supply of oxygen rich water and consumption by sediment within the redd. The results indicate that it is the former of these processes which is the most important, while the Sediment Oxygen Consumption (SOC), mainly associated with the silt and clay fractions, is considered to have a secondary effect on influencing the egg zone abiotic properties. These findings have implications for how we manage the sediment delivery problem.

Pattison, Ian; Sear, David; Collins, Adrian; Jones, Iwan; Naden, Pam

2013-04-01

250

Transbronchial fine needle aspiration.  

PubMed Central

In a pilot study, 21 patients underwent transbronchial fine needle aspiration (TBFNA) using a 45 cm-22 gauge needle guided by means of a semi-rigid metal sleeve, which was introduced through a standard rigid bronchoscope. A total of 33 aspirations were performed from main carina (15), paratracheal (five), and lobar carinal (13) foci. Six aspirations yielded malignant cellular samples, 22 aspirations presented only normal cells, and in five no adequate cellular sample was obtained. Fifteen patients underwent surgical exploration (mediastinoscopy with or without thoracotomy). Four of the cytologically malignant cases were explored and in three the aspiration site was confirmed histologically. In the remaining patients where the site of aspiration was explored, no tumour was demonstrated in the cytologically negative or cytologically inadequate cases. There were no complications from TBFNA. We suggest that TBFNA is useful in determining mediastinal malignant involvement rapidly and with lesser invasion than with current techniques. Images

Lemer, J; Malberger, E; Konig-Nativ, R

1982-01-01

251

Water Use for Cultivation Management of Watermelon in Upland Field on Sand Dune  

NASA Astrophysics Data System (ADS)

Early-maturing cultivation of watermelon in a plastic tunnel was invetigated in upland field on sand dune on the coast of the Japan Sea to find water use to control blowing sand and to transplant seedlings. This region has low precipitation, low humidity, and strong wind in March and April, when sand is readily blown in the field. Water is used to control blowing sand on days with precipitation below 5 mm, minimum humidity below the meteorological average in April, and maximum wind velocity above the meteorological average in April. For the rooting and growth of watermelon seedlings, soil temperature needs to be raised because it is low in April. Ridges are mulched with transparent, porous polyethylene films 10 or more days before transplanting the seedlings and irrigated with sprinklers on fine days for the thermal storage of solar energy. The stored heat steams the mulched ridges to raise soil temperature to 15°C or higher on the day of transplanting the seedlings. The total amount of irrigation water used for watermelon cultivation was 432.7 mm, of which 23.6 mm was for blowing sand control and 26.6 mm was for transplanting the seedlings. The combined amount, 50.2 mm, is 11.6% of the total amount of water used for cultivation management.

Hashimoto, Iwao; Senge, Masateru; Itou, Kengo; Maruyama, Toshisuke

252

Geologic assessments and characterization of marine sand resources - Gulf of Mexico region  

USGS Publications Warehouse

The U.S. Geological Survey conducts geologic surveys and research in marine areas of the United States and its territories and possessions. An objective in some of the investigations is locating and evaluating marine sand and gravel resources and interpretation of the origins of the sand body deposits. Results from such studies over the past 30 years show that many extremely large deposits are located close to expanding metropolitan areas, which have a need for aggregate materials for construction, and near-developed coastal areas, where beach replenishment may be used to mitigate coastal erosion. The Gulf of Mexico continental shelf from the Florida Peninsula to the Mexico border is an enormous area, but little attention has been directed on sand and gravel resources. Based on limited surveys, the total sand and gravel resources for the entire Gulf of Mexico is estimated to be 269 billion cubic meters. However, the sand tends to be fine-grained and is often mixed with mud; gravel deposits, except for shell, are mostly nonexistent.

Williams, S. Jeffress; Cichon, Helena, A.

1993-01-01

253

Investigating Sand on the Coast of Oregon and Washington.  

ERIC Educational Resources Information Center

Describes factors affecting sand composition and distribution along coastlines. Uses variations in sand types along the Oregon coast to illustrate the influences of sand grain density, wave action, and headlands on sand movements. Describes the seasonal movement of sand across beaches. (DLH)

Komar, Paul D.

2002-01-01

254

Automated Camera Array Fine Calibration  

NASA Technical Reports Server (NTRS)

Using aerial imagery, the JPL FineCalibration (JPL FineCal) software automatically tunes a set of existing CAHVOR camera models for an array of cameras. The software finds matching features in the overlap region between images from adjacent cameras, and uses these features to refine the camera models. It is not necessary to take special imagery of a known target and no surveying is required. JPL FineCal was developed for use with an aerial, persistent surveillance platform.

Clouse, Daniel; Padgett, Curtis; Ansar, Adnan; Cheng, Yang

2008-01-01

255

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

256

A high-efficiency, low-cost aeolian sand trap  

NASA Astrophysics Data System (ADS)

We present a design for an aeolian sand trap that is based on the streamer trap concept used in sediment transport studies. The trap is inexpensive, has excellent trapping efficiency, is durable, and easy to use. It is fabricated from stainless steel that is cut and bent to form a frame to support a fine nylon mesh. Typical trap openings are 100 mm wide and 25, 50, or 100 mm high. Traps are 250 mm long, and are stackable to measure vertical characteristics of saltation. The nylon mesh has 64 ?m openings that comprise 47% of the area of the material. Aerodynamic efficiency was tested in a wind tunnel, and sediment trapping efficiency evaluated in field deployments. Both evaluations support the use of this trap for short-term measurements.

Sherman, D. J.; Swann, C.; Barron, J. D.

2014-06-01

257

Continuous fine ash depressurization system  

DOEpatents

A system for depressurizing and cooling a high pressure, high temperature fine solid particles stream having entrained gas therein. In one aspect, the system has an apparatus for cooling the high pressure, high temperature fine solid particles stream having entrained gas therein and a pressure letdown device for depressurization by separating the cooled fine solid particles from a portion of the fine solid particles stream having entrained gas therein, resulting in a lower temperature, lower pressure outlet of solid particles for disposal or handling by downstream equipment.

Liu, Guohai (Birmingham, AL); Peng, Wan Wang (Birmingham, AL); Vimalchand, Pannalal (Birmingham, AL)

2011-11-29

258

Sulfidization of Witwatersrand black sands: From enigma to myth  

NASA Astrophysics Data System (ADS)

Reassessment of the nature and distribution of iron-titanium oxide minerals vs. pyrite in several South African Archean arenaceous sequences and conglomerates shows that in rocks of the Swaziland, Pongola, and Witwatersrand Supergroups, (1) pyrite of allogenic and/or authigenic origin is the predominant heavy mineral; (2) iron-titanium oxides generally take the form of very fine grained, dispersed rutile-leucoxene replacements after earlier black-sand minerals; (3) iron-titanium oxides constitute 1%-6% of the total heavy minerals; and (4) the phenomenon of sulfidization of iron-titanium oxide minerals is evident only on a very local scale. Exceptions to points 1 and 3 occur in conglomerates of the Dominion Group, which were derived from a pegmatitic terrain. The lack of macroscopically visible iron-titanium oxide minerals in the Witwatersrand conglomerates is a result of a combination of two factors. First, recycling of older sedimentary material was critical to the genesis of the conglomerates; about 60% of the source area consisted of arenaceous sequences. Iron-titanium mineral grains from this source had been altered to rutile-leucoxene prior to erosion, and thus did not contribute fresh iron-titanium minerals to the conglomerates. Second, those minerals derived from the remaining 40% of the source area were altered and decomposed to rutile-leucoxene in the Witwatersrand conglomerates. Furthermore, much of the resulting finely dispersed material helped to form brannerite, an important titanium sink. There is no need to invoke widespread sulfidization of black sands to account for the supposed lack of iron-titanium minerals and abundance of pyrite in the Witwatersrand conglomerates and ores.

Reimer, Thomas O.; Mossman, David J.

1990-05-01

259

Photoacoustic infrared spectroscopy of Syncrude post-extraction oil sand.  

PubMed

Rapid- and step-scan photoacoustic (PA) infrared spectra of three fractions of a Syncrude post-extraction oil sand were analyzed in detail in this work. The rapid-scan spectra showed that the samples were comprised primarily of kaolinite, quartz, silica, siderite, and residual hydrocarbons, and that the proportions of these constituents were different for each fraction. Depth profiling of the three post-extraction oil sands was accomplished using both rapid- and step-scan PA infrared spectroscopy. The results confirmed that kaolinite is more abundant in the near-surface region, whereas quartz and hydrocarbons are concentrated at greater depths. The modulation frequency dependence of the PA intensities for all three fractions was consistent with a model in which the samples are thermally thick; in other words, the thermal diffusion length (roughly equal to the sampling depth) was less than the particle sizes of all three samples. The results of this study are consistent with published reports on the PA infrared spectra of fine tailings generated during bitumen extraction and the spectroscopic and thermophysical characterization of clay soils and an appropriate model clay. PMID:16388979

Michaelian, Kirk H; Hall, Robert H; Kenny, Kimberly I

2006-06-01

260

Adding Value to Alberta's Oil Sands  

Microsoft Academic Search

A rapidly expanding oil sands industry and a dwindling supply of feedstock for Alberta's ethane-based petrochemical industry have stimulated interest in evaluating bitumen for producing a broad slate of refined products, including petrochemicals. Two industry\\/government studies evaluated different process schemes for integrating oil sands, refining, and petrochemical operations and convert heavy gas oils into both refined products and petro- chemicals.

S. Laureshen; P. D. CLARK; M. P. DU PLESSIS

2006-01-01

261

Separation of Bitumen from Bituminous Sands  

Microsoft Academic Search

THE separation of the bitumen from the Alberta bituminous sands by washing with hot water has been under study by the Research Council of Alberta for a number of years. It has been found that generally good separation can be effected by first thoroughly mixing the bituminous sand with about one-fifth of its weight of a solution of commercial silicate

K. A. Clark

1931-01-01

262

Syncrude-oil from Alberta's tar sands  

Microsoft Academic Search

Synthetic crude oil can be produced from bitumen contained in oil sands such as those located in Alberta, Canada. The most recent plant to come on stream, that of Syncrude Canada Ltd., mines the oil sand by open pit methods, recovers the bitumen using the hot water flotation process, and produces synthetic crude from bitumen by coking and hydrotreating. The

1980-01-01

263

Future of heavy crude and tar sands  

Microsoft Academic Search

The 106 papers which were presented at the First International Conference on the Future of Heavy Crude and Tar Sands, held in Edmonton, Alberta are incorporated in this volume. They are grouped under the following sections: (1) role of heavy crude oils and tar sands in world energy; (2) major known occurrences; (3) chemistry and geochemistry; (4) geology; (5) resource

R. F. Meyer; C. T. Steele

1981-01-01

264

Explorations with the Sand and Water Table.  

ERIC Educational Resources Information Center

Presents sand 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 sand and water toys made from one-liter plastic bottles. (KB)

Texas Child Care, 2001

2001-01-01

265

Sand Tray Group Counseling with Adolescents  

ERIC Educational Resources Information Center

Sand tray group counseling with adolescents is an activity-based intervention designed to help participants address specific intrapersonal concerns, learn important skills of socialization, and develop a caring community. The main focus of the group is building small worlds with miniature figures in individual trays of sand and having an…

Draper, Kay; Ritter, Kelli B.; Willingham, Elizabeth U.

2003-01-01

266

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

267

RADIUM REMOVAL USING SORPTION TO FILTER SAND  

EPA Science Inventory

The study evaluated the use of a novel sand filtration process that exploits the natural capacity of filter sand to sorb radium through the use of a periodic dilute acid rinse to maintain its sorptive capacity. Batch studies were conducted to determine distribution coefficients s...

268

Cracking the tight sands of Texas  

Microsoft Academic Search

Tight gas is one of several forms of unconventional gas promising to be an important source of domestic energy in the future. Cracking the tight sands in Texas, Colorado, and the Appalachian Basin could yield a 10-yr supply of natural gas. Methods of accomplishing this fracturing are described, such as pumping fluids and propping agents into dense sand under enough

Geddie

2009-01-01

269

GRI Program for Tight Gas Sands Research  

Microsoft Academic Search

GRI (Gas Research Institute) is proceeding with six projects for tight gas sands research, involving analyses for producing natural gas from tight blanket sands that are presently considered as non-commercial. The program plan is comprised of a sequence of projects relating to resource identification, formation evaluation, fluids and proppants investigations, fracture design, reservoir modeling, and staged field tests with technology

Patrick OShea; William Murphy

1982-01-01

270

Update on federal tight sands incentive policies  

Microsoft Academic Search

Recognizing the great potential of increased domestic tight sands production in reducing imports of foreign energy, several branches of the federal government have initiated policies to encourage development of this resource. However, these policies have been slow in formulation, and some are potentially in conflict with each other. Two characteristics of tight sands gas have led to it being singled

Buch

1980-01-01

271

Why are ripples absent in coarse sands?  

NASA Astrophysics Data System (ADS)

Current ripples are perhaps the most abundant and common bedform and sedimentary structure in contemporary and ancient sediments, with their stability field being dependent on the applied bed shear stress and grain size. The ripple stability field begins to narrow in medium sand with ripples ceasing to exist in sands coarser than c. 0.7mm diameter. Leeder (1980) proposed that the absence of ripples in coarse sands is linked to the influence of increasing grain roughness that strengthens vertical mixing of fluid near the bed, and thereby disrupts flow separation over bed defects from which ripples normally propagate. In this paper, we use a novel thin (5mm wide) flume to investigate the dynamics of bedforms developed in a very coarse sand and use PIV to detail the dynamics of flow associated with the initial bedforms developed in this sand. We highlight the irregular wavelength, height and migration characteristics of these bedforms and contrast this with ripples developed in a medium sand. Furthermore, we utilize the near-bed PIV data to examine vertical flow velocities and the possible role of hyporheic flow upwelling in the bedform leeside. Such hyporheic flow, induced by pressure gradients established around the bedform, can lead to significant modifications to the leeside flow separation zone that may be contribute to the absence of current ripples in coarse sands. Reference Leeder, M.R. 1980 On the stability of lower stage plane beds and the absence of ripples in coarse sands, J. Geol. Soc. London, 137, 423-30.

Best, J.; Barros, J.; Blois, G.; Christensen, K. T.

2013-12-01

272

Liquefaction in Subsurface Layer of Sand  

USGS Multimedia Gallery

Ground shaking triggered liquefaction in a subsurface layer of sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and silt, which moved from right to left toward the Pajaro River. This mode of ground failure, termed "lateral spreading," is a p...

2009-01-26

273

Use of Foundry Sands in Transportation Applications.  

National Technical Information Service (NTIS)

The primary objective of this project was to verify the availability and suitability of Texas-generated foundry sand (FS) for TxDOT and to develop specifications for use of these sands in TxDOT construction and maintenance applications. Extensive literatu...

C. Vipulanandan S. Cho S. Wang

2005-01-01

274

Fine root dynamics for forests on contrasting soils in the Colombian Amazon  

NASA Astrophysics Data System (ADS)

It has been hypothesized that as soil fertility increases, the amount of carbon allocated to below-ground production (fine roots) should decrease. To evaluate this hypothesis, we measured the standing crop fine root mass and the production of fine roots (<2 mm) by two methods: (1) ingrowth cores and, (2) sequential soil coring, during 2.2 years in two lowland forests growing on different soils types in the Colombian Amazon. Differences of soil resources were defined by the type and physical and chemical properties of soil: a forest on clay loam soil (Endostagnic Plinthosol) at the Amacayacu National Natural Park and, the other on white sand (Ortseinc Podzol) at the Zafire Biological Station, located in the Forest Reservation of the Calderón River. We found that the standing crop fine root mass and the production was significantly different between soil depths (0-10 and 10-20 cm) and also between forests. The loamy sand forest allocated more carbon to fine roots than the clay loam forest with the production in loamy sand forest twice (mean±standard error=2.98±0.36 and 3.33±0.69 Mg C ha-1 yr-1, method 1 and 2, respectively) as much as for the more fertile loamy soil forest (1.51±0.14, method 1, and from 1.03±0.31 to 1.36±0.23 Mg C ha-1 yr-1, method 2). Similarly, the average of standing crop fine root mass was higher in the white-sands forest (10.94±0.33 Mg C ha-1) as compared to the forest on the more fertile soil (from 3.04±0.15 to 3.64±0.18 Mg C ha-1). The standing crop fine root mass also showed a temporal pattern related to rainfall, with the production of fine roots decreasing substantially in the dry period of the year 2005. These results suggest that soil resources may play an important role in patterns of carbon allocation to the production of fine roots in these forests as the proportion of carbon allocated to above- and below-ground organs is different between forest types. Thus, a trade-off between above- and below-ground growth seems to exist with our results also suggesting that there are no differences in total net primary productivity between these two forests, but with higher below-ground production and lower above-ground production for the forest on the nutrient poor soil.

Jiménez, E. M.; Moreno, F. H.; Peñuela, M. C.; Patiño, S.; Lloyd, J.

2009-12-01

275

NEARSHORE SAND SOURCES FOR AMERICAN SAMOA: AN ALTERNATIVE TO USING BEACH SAND.  

USGS Publications Warehouse

Using a combination of geophysical techniques, in situ observations, and sampling by scuba divers, we investigated along the south shore of Tutuila Island, American Samoa, for nearshore sand deposits. To minimize the impact of future sand dredging on the island's littoral sediments, the search took place in a narrow zone between the outside of the fringing reef and the 30-m bathymetric contour. Because the sand will be used by the Samoans in a variety of ways, an area high in siliciclastic sand - Nua-Se'etaga Bay - and two areas containing only carbonate sand - Faga'itua Bay and Nafanua Bank - were inspected in detail. Results of the exploration program are discussed.

Dingler, John, R.; Reiss, Thomas, E.

1987-01-01

276

Depositional and diagenetic history of Bodcaw Sand, Cotton Valley Group (Upper Jurassic), Longwood field, Caddo Parish, Louisiana  

SciTech Connect

The Bodcaw Sand contains fine-grained sandstones and siltstones deposited within a barrier-bar sequence. Based on vertical changes in sedimentary structures, texture, and mineralogic composition, three distinct lithofacies (upper, middle, and lower shoreface) within the Bodcaw Sand and two associated logoonal lithofacies were identified. Cross-stratification and low-angle laminations, rarely disrupted by biogenic structures, characterize the fine-grained upper shoreface sandstones. Middle shoreface sandstones have undergone extensive reworking by biotic and abiotic factors. Few primary sedimentary structures or early generation trace fossils are preserved in middle shoreface sandstones. Lower shoreface siltstones and very fine-grained sandstones contain lenticular and wavy bedding features that are disrupted in many places by bioturbation. The Bodcaw Sand has low porosity and permeability values. Vertical and lateral variation in porosity and permeability values are related to original deposition and subsequent diagenesis of Cotton Valley sediments. The Bodcaw Sand has had a complicated diagenetic history. Compaction, cementation, replacement, and dissolution have modified primary rock properties following deposition of barrier-bar sediments. Authigenic cementation plays an important role in modification of reservoir properties. Important authigenic minerals identified in the Bodcaw include silica, carbonates, and phyllosilicates. Two major diagenetic sequences are recognized on the basis of textural relationships between allogenic grains and authigenic constituents.

Russell, B.J. Jr.; Sartin, A.A.

1984-09-01

277

Solvent leaching of tar sands  

SciTech Connect

Solvent flooding is the basis of a wide range of enhanced oil recovery methods, and has been shown to be a possible method of creating initial steam injectivity in tar sands. This paper presents a unique model of dissolution of a semi-solid bitumen, resulting from the injection of a solvent. The solution of the mathematical equations, describing this phenomena is discussed. Results, including a series of two-dimensional problems, are presented. Numerical aspects are addressed. It is shown that three dimensionless groups control the bitumen leaching process. In the absence of fluid flow, the dissolution of bitumen is governed by the Damkohler and solvent capacity numbers. In the absence of dissolution, the Peclet number governs miscible displacement in the fluid phase. This paper presents computational results for a series of two-dimensional problems for a five-spot flow geometry, showing the importance of the model developed.

Oguztoreli, M.; Faroqu, S.M.

1983-11-01

278

Preserving inland drift sands in the Netherlands  

NASA Astrophysics Data System (ADS)

Inland drift sands in the Netherlands are an important landscape type within the Dutch nature. They represent an important pioneer habitat which has become rare in European nature. Under current climate and environmental conditions (i.e. high N-deposition) these inland drift sands tend to be rapid colonialized by vegetation and therefor lose their aeolian activity. To maintain the area bare sand, managers regularly remove the vegetation. Lack of proper knowledge about the geomorphological processes and even more important on the geomorphological structure of these drift sands, could lead to the loss of characteristic dune structure. In an interdisciplinary research project a new management strategy was developed in which the geomorphological processes and structure form the base for the planning process. To improve the awareness of these aspects among nature managers we developed a management tool "PROMME". Several activities were taken to communicate this with the people involved in the management of drift sands like a brochure and field workshops.

Riksen, M.; Sparrius, L.; Nijssen, M.; Keestra, S.

2012-04-01

279

Ecological release in White Sands lizards  

PubMed Central

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 Sands, 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 Sands relative to nearby dark soils habitats. Second, we characterize ecological release at White Sands by demonstrating density compensation in the three White Sands lizard species and expanded resource use in White Sands 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.

Roches, S Des; Robertson, J M; Harmon, L J; Rosenblum, E B

2011-01-01

280

Hematite Outlier and Sand Dunes  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 4 December 2003

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 sand sheet with no coherent structure, indicating that the sand layer thins out to the south and east.

Image information: VIS instrument. Latitude -4.4, Longitude 357.3 East (2.7 West). 19 meter/pixel resolution.

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.

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.

2003-01-01

281

13. SANDSORTING BUILDING, THIRD FLOOR, VIBRATING SCREENS FOR SAND SORTING, ...  

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

13. SAND-SORTING BUILDING, THIRD FLOOR, VIBRATING SCREENS FOR SAND SORTING, LOOKING SOUTHWEST - Mill "C" Complex, Sand-Sorting Building, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

282

Investigation of Re-Use Options for Used Traction Sand.  

National Technical Information Service (NTIS)

The Colorado Department of Transportation (CDOT) uses approximately 24,000 tons of traction sand annually, especially in mountain locations. Once traction sand is applied, street sweepers reclaim approximately 50% of the sand, which is either stockpiled a...

A. K. Pulley K. Baird

2010-01-01

283

Imaging of sand production in a horizontal sand pack by X-ray computed tomography  

SciTech Connect

A laboratory experiment was performed to better understand how sand production can increase heavy oil recovery. A horizontal sand pack with an orifice at one end modeled the production of oil and sand into a perforation in a vertical well. The sand pack was scanned using X-ray computed tomography (CT). The CT images revealed that a high-porosity channel (wormhole) formed in the pack while sand was produced. The wormhole followed regions within the pack where the porosity was higher, and, consequently, the unconfined compressive strength of the sand was lower. This experiment suggests that wormholes will form within the weaker sands of a formation. The development of these high-permeability channels increases the drainage of the reservoir, which leads to higher oil recovery.

Tremblay, B.; Sedgwick, G.; Forshner, K. [Alberta Research Council, Edmonton, Alberta (Canada)

1996-06-01

284

Fine-Tuning Corrective Feedback.  

ERIC Educational Resources Information Center

Explores the notion of "fine-tuning" in connection with the corrective feedback process. Describes a longitudinal case study, conducted in the context of Norwegian as a second a language, that shows how fine-tuning and lack thereof in the provision of written corrective feedback differentially affects a second language learner's restructuring of…

Han, ZhaoHong

2001-01-01

285

The effect of limited availability of N or water on C allocation to fine roots and annual fine root turnover in Alnus incana and Salix viminalis.  

PubMed

The effect of limited nitrogen (N) or water availability on fine root growth and turnover was examined in two deciduous species, Alnus incana L. and Salix viminalis L., grown under three different regimes: (i) supply of N and water in amounts which would not hamper growth, (ii) limited N supply and (iii) limited water supply. Plants were grown outdoors during three seasons in covered and buried lysimeters placed in a stand structure and filled with quartz sand. Computer-controlled irrigation and fertilization were supplied through drip tubes. Production and turnover of fine roots were estimated by combining minirhizotron observations and core sampling, or by sequential core sampling. Annual turnover rates of fine roots <1 mm (5-6 year(-1)) and 1-2 mm (0.9-2.8 year(-1)) were not affected by changes in N or water availability. Fine root production (<1 mm) differed between Alnus and Salix, and between treatments in Salix; i.e., absolute length and biomass production increased in the order: water limited < unlimited < N limited. Few treatment effects were detected for fine roots 1-2 mm. Proportionally more C was allocated to fine roots (?2 mm) in N or water-limited Salix; 2.7 and 2.3 times the allocation to fine roots in the unlimited regime, respectively. Estimated input to soil organic carbon increased by ca. 20% at N limitation in Salix. However, future studies on fine root decomposition under various environmental conditions are required. Fine root growth responses to N or water limitation were less pronounced in Alnus, thus indicating species differences caused by N-fixing capacity and slower initial growth in Alnus, or higher fine root plasticity in Salix. A similar seasonal growth pattern across species and treatments suggested the influence of outer stimuli, such as temperature and light. PMID:23963409

Rytter, Rose-Marie

2013-09-01

286

Compositional Variations of Rocknest Sand, Gale Crater, Mars  

NASA Astrophysics Data System (ADS)

The Curiosity rover spent over 40 sols at an aeolian deposit (termed Rocknest sand shadow deposit) that is several meters long (oriented north-south), 15-20 cm high (at crest) and about 50 cm wide. Material was scooped up from the subsurface to a depth of about 40 mm at five different locations on the deposit. Part of the sampled material was delivered to the analytical laboratories CheMin (x-ray diffraction) and SAM (pyrolysis, evolved gas analysis, gas chromatography, mass spectrometry, tunable laser spectroscopy) in the rover body. Scoop troughs and walls were imaged extensively by cameras onboard the rover (Mastcam, Mars Hand Lens Imager (MAHLI), Remote Microscopic Imager (RMI)) and probed by Laser Induced Breakdown Spectroscopy (LIBS) as provided by the ChemCam instrument. Images show that the top surface of the deposit is armored by a layer 1-3 grains thick of mm-sized, subrounded, dust-mantled grains. The bulk of the deposit is composed of particles smaller than 150 microns (fine and very fine sand and likely silt and dust). Furthermore, there are bright bands in the subsurface, a narrow one and a broad one at depths 2-4 mm and 20-30 mm, respectively. The images also provide evidence for crust formation and cementation as the scoop trough floors are littered by platy angular fragments and cemented clods. Many of the clods contain numerous sub-mm sized bright (sulfate rich?) inclusions. Chemical profiles (as provided by ChemCam data) do not clearly support the type of subsurface layering inferred from the images. However, chemical abundances (Li, Na, K, Mn, Fe, Ca, Mg, and Si) significantly deviating from average values are found at two different depths (respectively 15 and 25 mm). It is unclear when (and over which time scale) the Rocknest sand deposit in Gale Crater formed. In any case, mm-sized particles cannot be moved efficiently in the current aeolian regime. If the deposit has been immobile for an extended period of time, it is conceivable that Martian obliquity cycles (up to the near geologic past) caused ice deposition and partial melting of subsurface water ice which in turn may have sustained slow alteration of the uppermost part of the deposit (Arvidson et al., J. Geophys. Res., 115, E00F03, 2010); this hypothesis is consistent with the observed crust formation as well as the chemical variations in the near subsurface.

Goetz, Walter; Madsen, Morten B.; Edgett, Kenneth S.; Clark, Benton C.; Meslin, Pierre-Yves; Blaney, Diana L.; Bridges, Nathan; Fisk, Martin; Hviid, Stubbe F.; Kocurek, Gary; Lasue, Jeremie; Maurice, Sylvestre; Newsom, Horton; Renno, Nilton; Rubin, David M.; Sullivan, Robert; Wiens, Roger C.; MSL Science Team

2013-04-01

287

Seismic wave velocity of hydrate-bearing fine-grained sediments sampled from the Ulleung basin in East Sea, Korea  

NASA Astrophysics Data System (ADS)

Synthesizing gas hydrate in a fine-grained natural seabed sediment sample, mainly composed of silty-to-clayey soils, has been hardly attempted due to the low permeability. It has been known that hydrate loci in pore spaces and heterogeneity of hydrate growth in core-scale play a critical role in determining physical properties of hydrate-bearing sediments. In the presented study, we attempted to identify the effect of hydrate growth morphology on seismic velocities in natural fine-grained sediments sampled from the Ulleung Basin in East Sea. We synthesized CO2 hydrate in clayey silt sediments in an instrumented oedometric cell and measured seismic velocities during hydrate formation and loading processes. Herein, we present the experiment results on P-wave and S-wave velocities of gas hydrate-bearing fine-grained sediments. It is found that the geophysical properties of gas hydrate-bearing sediments are governed by hydrate saturation and effective stress as well as morphological feature of hydrate formation in sediments.

Kim, H.; Kwon, T.; Cho, G.

2012-12-01

288

3D seismic, geochemical and biostratigraphical analysis of Paleogene remobilized sand in the Norwegian-Danish Basin  

NASA Astrophysics Data System (ADS)

This study describes remobilized Paleogene sand occurring on the hanging-wall segment north of the major D-1 normal fault in the Norwegian-Danish Basin, eastern North Sea. The remobilized sand is observed on 3D seismic data in fine-grained Eocene host-strata as cross-cutting reflections with a typical tabular, V-shaped or wing-like geometry in the seismic cross-sections and a pronounced jack-up of the overlying succession onto which onlap can be observed. In map view the remobilized sand in certain areas have a channel-like appearance. The seismic observations indicate that the sand has a remobilized origin which may be partly depositional. Particularly the observed wings and jack-up on the seismic cross-sections indicate remobilization which potentially could be generated by two different processes: a) remobilization of depositional channel sand resulting in the formation of injected wings along the sides of the channel, or b) injection of remobilized sand from the deeper Paleocene strata causing jack-up and typically V-shaped intrusions. Injection of Paleocene sand into Eocene host strata is a well-known phenomenon from the nearby Paleogene Siri Canyon located c. 15 km north of the study area. In order to acquire more information about the intrusions a geochemical study and a detailed biostratigraphical dating of cuttings and sidewall core samples from the Floki-1 well was carried out. The Floki-1 well penetrates the remobilized sand and was drilled to test an apparent 4-way closure on prospect Eocene sand which by then was interpreted to be 100 % depositional. The geochemical study of the samples from the sand identified the Floki-sandstone as a very fine grained sand and silt with a matrix of very angular silt grains. The sand does not contain clays. The matrix appears to have formed by crushing of the sand grains. Thus, heavy minerals appear to have disintegrated by crushing but still most parts of the mineral grain is found together. Glauconite grains are strongly smeared. The sorting pattern, and the angular shape of silt sized matrix grains, and the intense shearing and deformation of glauconite grains indicates that the sand may have been injected under high pressure, resulting in massive crushing of detrital grains. The age dating mainly includes dinocysts analysis from seven sidewall core samples and nine cutting samples above, within and below the sand. It is expected that the sand should either be of Eocene age probably revealing a depositional origin with subsequent remobilization to the sides (process a), or a Paleocene age revealing injection from the deeper strata (process b). In order to address all observations, a potential model of generation may include elements of depositional sand combined with up-, downward and/or lateral injection which could have been facilitated by intense activity in the nearby D-1 fault. The study highlights the importance of interdisciplinary approaches in the interpretation of complex geological features formed by several geological processes and mechanisms.

Andresen, Katrine Juul; Rønø Clausen, Ole; Heilmann-Clausen, Claus; Friis, Henrik

2013-04-01

289

Fatal outcome of a sand aspiration.  

PubMed

Although extensive deep aspiration of sand, gravel, or dirt is a very rare incident, its consequences may be severe ranging from the necessity of immediate intensive care to death. Cases reported so far were due to external causes such as cave-ins, near drowning, or being buried under sand masses. We report a case of a 2 1/2-year-old boy who ingested sand while playing in a sandbox with his older brother. Despite early resuscitation and endotracheal intubation efforts, he died subsequently showing clinical signs of asphyxia due to airway obstruction. Autopsy revealed sand masses obstructing the trachea and lobar bronchi of both lungs as well as brain edema, while no signs of blunt trauma, forced sand ingestion, or preexisting medical conditions were found. This case demonstrates that fatal self-administered sand aspiration may occur in early childhood. The pathophysiology of the lethal outcome with regard to the physical properties of sand and implications for the clinical assessment of emergency situations are discussed. PMID:18546004

Kettner, M; Ramsthaler, F; Horlebein, B; Schmidt, P H

2008-11-01

290

Invasive plants on disturbed Korean sand dunes  

NASA Astrophysics Data System (ADS)

The sand 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 sand 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 sand 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 sand 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, sand 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 sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic soils, and conservation of surrounding sand dune areas.

Kim, Kee Dae

2005-01-01

291

Fecal indicators in sand, sand contact, and risk of enteric illness among beachgoers  

PubMed Central

Background Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear. Methods In 2007, visitors at two recreational marine beaches were asked on the day of their visit about sand 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 sand were measured using culture and molecular methods. Results We analyzed 144 wet sand 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 sand contact. Among those digging in sand compared with those not digging in sand, a molecular measure of Enterococcus spp. (calibrator cell equivalents/g) in sand 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 sand, 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 sand exposure. Conclusions We observed a positive relationship between sand contact activities and enteric illness as a function of concentrations of fecal microbial pollution in beach sand.

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.

2011-01-01

292

On anthropic principles fine tuning and chaos  

Microsoft Academic Search

Anthropic principles were grown from the problem of fine tuning. Although anthropic principles have been discussed in cosmology for years there are no exact definitions for fine tuning. To define the fine tuning quantitatively we investigate how one can use Lyapunov indicator in the definition of fine tuning. Our result is an alternative Lyapunov indicator, which shows how fine tuned

Zsolt Hetesi; L. Végh

2006-01-01

293

FINE PORE (FINE BUBBLE) AERATION OF MUNICIPAL WASTEWATERS  

EPA Science Inventory

The paper summarizes the current information on fine pore aeration systems. Types of media, types of diffusers, piping and layout, characteristics of diffusers, clear and process water performance, operation and maintenance, diffuser fouling and economic analyses are reviewed. Th...

294

Fine Pore (Fine Bubble) Aeration of Municipal Wastewaters.  

National Technical Information Service (NTIS)

The paper summarizes the current information on fine pore aeration systems. Types of media, types of diffusers, piping and layout, characteristics of diffusers, clear and process water performance, operation and maintenance, diffuser fouling and economic ...

R. C. Brenner A. E. Eralp W. C. Boyle

1986-01-01

295

Developments in tar sands in 1984  

SciTech Connect

Interest and activity in tar sands development are progressing slowly with cautious optimism. Scaled-down, modular, in-situ pilot projects allow companies to react quickly to fluctuations in market conditions or the global economy. In addition, new drilling techniques and increasing efficient methods of bitumen recovery are being field tested. Since most worldwide tar sand production is from Canada, this paper centers on Canadian issues and project developments in the Peace River, Cold Lake, Athabasca, and Wabasca regions. The improvements there can be used as a model for other tar sands projects in similar economic situations and geological regions. 4 figures, 3 tables.

Seifert, S.R.; Lennox, T.R.

1985-10-01

296

Developments in tar sands in 1984  

SciTech Connect

Interest and activity in tar sands development are progressing slowly with cautious optimism. Scaled-down, modular, in-situ pilot projects allow companies to react quickly to fluctuations in market conditions or the global economy. In addition, new drilling techniques and increasingly efficient methods of bitumen recovery are being field tested. Since most worldwide tar sand production is from Canada, this paper centers on Canadian issues and project developments in the Peace River, Cold Lake, Athabasca, and Wabasca regions. The improvements there can be used as a model for other tar sands projects in similar economic situations and geologic regions.

Seifert, S.R.; Lennox, T.R.

1985-10-01

297

VideoLab: Swimming in Sand  

NSDL National Science Digital Library

Physics can model organisms running or crawling on solids, and those flying and swimming through fluids. Yet the desert-dwelling sandfish lizard moves through sand -- a solid- and fluid-like medium. Using high-speed x-ray imaging, Maladen et al. discovered that, although the sandfish uses its legs to run on top of sand and to bury itself underneath (movie 1), once subsurface, sandfish use undulatory locomotion (movie 2), slithering through sand with its unused limbs tucked close to its body (movie 3).

Ryan D. Maladen (Georgia Institute of Technology;Interdisciplinary Bioengineering Program); Ying Ding (Georgia Institute of Technology;School of Physics); Chin Li (Georgia Institute of Technology;School of Physics); Daniel Goldman (Georgia Institute of Technology;Interdisciplinary Bioengineering Program and School of Physics)

2009-07-17

298

Syncrude-oil from Alberta's tar sands  

SciTech Connect

Synthetic crude oil can be produced from bitumen contained in oil sands such as those located in Alberta, Canada. The most recent plant to come on stream, that of Syncrude Canada Ltd., mines the oil sand by open pit methods, recovers the bitumen using the hot water flotation process, and produces synthetic crude from bitumen by coking and hydrotreating. The product is competitive in price with imported conventional crude at today's world prices. The lead time and investment required to put a plant on stream are substantial. Nevertheless, synthetic crude from oil sands has the potential to fill a significant portion of Canada's liquid fuel requirements.

Lund, C.N.

1980-12-01

299

Developments in tar sands in 1981  

SciTech Connect

Activity in tar sands projects during 1981 continued at a very significant pace. The bulk of activity was in Canada, where 38 pilot projects were active, 2 commercial plants continued operations, 1 commercial scheme was canceled, and another was put into the twilight zone. Activity in the United States was low, whereas Venezuelan efforts reflect a firm commitment toward commercial development. The tenacious attitude of both industry and certain governments in the pursuit of tar sands development will keep the greater tar sands dream alive.

Wennekers, J.H.N.

1982-11-01

300

Sound-producing dune and beach sands  

NASA Technical Reports Server (NTRS)

Acoustic and seismic outputs of booming sands and singing (squeaking) sands in response to shearing are investigated, with samples of silent sands studied for controls. A vertical-axis geophone buried at shallow depth and an air microphone were used in the studies. The frequency spectra of the acoustic and seismic responses, propagation delays, comparison of acoustic and seismic traces, grain size and grain surface texture, particle morphology, coherent behavior of grains in assemblages, and relation to prevalent local winds were studied. Mechanisms are still obscure and disputed; slumping and avalanches were induced artificially in some studies. Existence of booming dune phenomena on Mars or on the moon is conjectured.

Lindsay, J. F.; Criswell, D. R.; Criswell, T. L.; Criswell, B. S.

1976-01-01

301

Ultra-fine coal characterization  

SciTech Connect

The objectives of this Preparation Program include beneficiation of coal to produce high-quality solid or slurry fuel as alternatives for fuel oil and natural gas. Fine grinding is a necessary prerequisite if physical separations are being considered during such beneficiation since the impurity minerals are very fine-grained and dispersed throughout the coal mass. It is the purpose of this research to study the properties of ultra-fine coal since the behavior of such coal can be different from the behavior of the coarser coal normally encountered during cleaning. Research was divided into six tasks: (1) Sample Collection and Preparation: Suitable samples of the base case coal and eight other representative coals were collected and prepared for the subsequent test work. (2) Chemical and Bulk Property Determinations: Compositions, washabilities, moisture levels, and other coal properties which effect behavior of the fine coal in beneficiation systems were determined for each coal. (3) Mineral Liberation Studies: Liberation of the mineral matter in the coal achieved by fine and ultra-fine grinding and the degree of liberation was determined. (4) Hydrodynamic Study of Particles and Slurries: The deviation of individual fine coal particles from Stoke's Law free-settling behavior was determined. (5) Study of the Surface Properties of Particles: The surface characteristics of fine particles of coal which relate to the effectiveness of beneficiation processes were studied. These included electrical charges in aqueous media (zeta potential) and the wettability of the coals (contact angles), and (6) Predictive Model Development: Empirical predictive equations were developed relating measurable coal characteristics of ultra-fine coal to the response of the coal to froth flotation. Accomplishments are discussed in this report. 55 refs., 53 figs., 64 tabs.

Smit, F.J.; Odekirk, J.R.; Baltich, L.K.

1988-12-01

302

Sustainable agriculture and nitrogen reduction: an open field experiment using natural zeolitites in silty-clay reclaimed soil at Codigoro (Po River Delta, Ferrara, Italy)  

NASA Astrophysics Data System (ADS)

Following the guidelines of Nitrate and Water Framework Directives (91/676/CEE, 200/60/CE) an innovative integrated zeolitite cycle is being tested on a reclaimed clayey-silt soil in the Po Delta area (Ferrara Province, Italy), in the framework of the EU-funded ZeoLIFE project (LIFE+10 ENV/IT/000321). Natural zeolitites are pyroclastic rocks containing more than 50% of zeolites, a kind of hydrous minerals with peculiar physical and chemical properties, like high and selective cation exchange capacity (CEC), molecular adsorption and reversible dehydration. Zeolitites can trap NH4+ from solutions and release it gradually to the plant roots once they have been mixed in agricultural soils, allowing both fertilization and irrigation reduction and improvement of the yield. The fertilization reduction can result in a decrease of the nitrate content in groundwater and surface waters, ultimately leading to a mitigation of nutrient excess in the environment. Similarly, reduction of irrigation water means a minor exploitation of the water resource. The selected material used in the project is a chabazite zeolitite coming from a quarry near Sorano in Central Italy (Bolsena volcanic district). The open-field experimentation foresees two year of cultivation. A surface of about 6 ha has been divided into six parcels: three control parcels are cultivated and irrigated in traditional way; two parcels have been added with coarse-grained (ø = 3- 6 mm) natural zeolitite at different zeolitite/soil ratios (5 kg/m2 and 15 kg/m2) and one has been mixed with fine-grained (ø < 3 mm) NH4+-charged zeolitite at 10 kg/m2. Zeolitite/soil ratios have been determined upon a series of greenhouse tests, and the ammonium enriched material is obtained by cation exchange with swine manure in a specifically conceived prototype. The environmental quality of soil and water in each parcel is monitored by periodic soil, groundwater and porewater analyses. Soil EC, temperature and volumetric water content are continuously measured with probes at different depth (5-30-50-100-150 cm). The quality of surface water is checked by analyzing the outflow from the drains of the sub-irrigation system installed in the field. An automated meteorological station has been also installed in order to quantify rainfalls and sun irradiation for water balance calculation. During the first year, a no-food variety of sorghum has been cultivated. In the parcels treated with natural zeolitite and in that bearing NH4+-charged zeolitite, the fertilization has been reduced by 30% and 50% with respect to the controls. Notwithstanding these reductions, the yield increased by 5% and 15% in the parcel added with natural zeolitite and in that treated with NH4+-charged zeolitite, respectively. As confirmed by previously performed laboratory leaching tests, NH4+ in porewater and surface water was comparable in all parcels (

Faccini, Barbara; Di Giuseppe, Dario; Mastrocicco, Micòl; Coltorti, Massimo; Colombani, Nicolò; Ferretti, Giacomo

2014-05-01

303

Uprated fine guidance sensor study  

NASA Technical Reports Server (NTRS)

Future orbital observatories will require star trackers of extremely high precision. These sensors must maintain high pointing accuracy and pointing stability simultaneously with a low light level signal from a guide star. To establish the fine guidance sensing requirements and to evaluate candidate fine guidance sensing concepts, the Space Telescope Optical Telescope Assembly was used as the reference optical system. The requirements review was separated into three areas: Optical Telescope Assembly (OTA), Fine Guidance Sensing and astrometry. The results show that the detectors should be installed directly onto the focal surface presented by the optics. This would maximize throughput and minimize point stability error by not incoporating any additional optical elements.

1984-01-01

304

'RAT' Leaves a Fine Mess  

NASA Technical Reports Server (NTRS)

This graph shows the light signatures, or spectra, of two sides of the rock dubbed 'Bounce,' located at Meridiani Planum, Mars. The spectra were taken by the miniature thermal emission spectrometer on the Mars Exploration Rover Opportunity. The left side of this rock is covered by fine dust created when the rover drilled into the rock with its rock abrasion tool. These 'fines' produce a layer of pyroxene dust that can be detected here in the top spectrum. The right side of the rock has fewer fines and was used to investigate the composition of this basaltic rock.

2004-01-01

305

Genetic features of soils on marine sands and their windblown derivatives on the White Sea coast (the Kola Peninsula)  

NASA Astrophysics Data System (ADS)

The Quaternary deposits on the Tersk coast of the White Sea are represented by marine deposits (the Tersk sands) enriched in the sea-sorted eluvium of the red Tersk sandstone. These deposits and the soils developed from them are characterized by the predominance of the fine sand fraction and the absence of gravel and the coarser fractions. The sediments derived from the red 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 sands subjected to afforestation and from coastal marine sands under a relatively thin natural plant cover. Iron-illuvial podzols buried under a thin sand layer preserve the Al-Fe-humus type of the profile differentiation. In the recently deposited sand layer, the eluvial-illuvial redistribution of the chemical elements is absent.

Pereverzev, V. N.; Kazakov, L. A.; Chamin, V. A.

2011-01-01

306

Soil texture affects soil microbial and structural recovery during grassland restoration  

Microsoft Academic Search

Many biotic and abiotic factors influence recovery of soil communities following prolonged disturbance. We investigated the role of soil texture in the recovery of soil microbial community structure and changes in microbial stress, as indexed by phospholipid fatty acid (PLFA) profiles, using two chronosequences of grasslands restored from 0 to 19 years on silty clay loam and loamy fine sand

Elizabeth M. Bach; Sara G. Baer; Clinton K. Meyer; Johan Six

2010-01-01

307

Electrostatic force on saltating sand  

NASA Astrophysics Data System (ADS)

In blizzards and sandstorms, wind transport of particles is associated with separation of electrostatic charge. Moving particles develop charge of sign opposite the electrostatic charge on stationary surface particles. This electrification produces forces in addition to the gravitational and fluid friction forces that determine trajectories for particles being transported in saltation. Evaluating electrostatic forces requires the electric field strength very near the saltation surface and charge-to-mass ratios for the moving particles. In a low-level blowing sand event we measured an average charge-to-mass ratio of +60 ?C kg-1 on the saltating particles at 5-cm height and a maximum electric field of +166 kV m-1 at 1.7-cm height, in wind gusts near 12 m s-1 at 1.5-m height. The electrostatic force estimated from these measurements was equal in magnitude to the gravitational force on the saltating particles. Including electrostatic forces in the equations of motion for saltating particles may help explain discrepancies between measurements and models of saltation transport.

Schmidt, D. S.; Schmidt, R. A.; Dent, J. D.

1998-04-01

308

Comparisons of Vibrated Density and Standard Compaction Tests on Sands with Fines.  

National Technical Information Service (NTIS)

Generally, two laboratory test methods, relative density and standard compaction (impact), are used in establishing density requirements for the placement of embankment materials. The relative density test method is specified for cohesionless soils, gener...

F. C. Townsend

1972-01-01

309

Alluvial sediment or playas: What is the dominant source of sand and silt in desert soil vesicular A horizons, southwest USA  

NASA Astrophysics Data System (ADS)

Vesicular A (Av) soil horizons form beneath desert pavements from the accretion of aeolian sediment (dust) commonly thought to be derived primarily from desiccating pluvial lakes and playas, with contributions from ephemeral washes and alluvial fans. Particle size distributions of Av horizons are typically bimodal with primary modes of very fine silt and fine sand, suggesting that the horizon matrix is derived from multiple sources. Here we conduct detailed chemical and physical analysis of both Av horizon soil samples and potential sources of aeolian sediment to better constrain the relative contributions of dust associated with the development of Av horizons. Geochemical data from both sand (125-250 µm) and silt (2-32 µm) fractions in Av horizons and potential dust sources in the eastern Mojave Desert and western Sonora Desert, USA, point to large contributions from nearby sources including distal alluvial fans and washes, and comparably lower contributions from regional sources such as playas. The silt mode is derived from suspension transport of dust, and the fine sand mode is derived from saltating sand. The desiccation of pluvial lakes in the Mojave Desert is commonly believed to have driven episodes of aeolian activity, contributing to sand dunes and Av horizon formation. We propose that alluvial fans and washes are underappreciated as desert dust sources and that pulses of dust from late Pleistocene and Holocene alluvial fans dwarfed pulses of dust from desiccating pluvial lakes in the eastern Mojave Desert.

Sweeney, Mark R.; McDonald, Eric V.; Markley, Christopher E.

2013-03-01

310

On the nature of Athabasca Oil Sands.  

PubMed

The existence of a thin aqueous film, separating bitumen (a form of heavy oil) from inorganic solids in Athabasca Oil Sands, is analysed based on "first principles". There is a general consensus in the literature on the hydrophilic character of the solids in oil sands. However, a review of the references cited in support of the solids being encapsulated in thin water envelopes produced a surprising lack of evidence. A theoretical analysis indicates that a water film separating clean, hydrophilic quartz and bitumen is stable under most conditions, and unstable for acidic oil sand ores. The existence of water-wet solids in the Athabasca Oil Sands remains a reasonable yet unproven postulate. It could therefore be dangerous to accept the water-wet solids postulate and then use it to interpret other phenomena. PMID:15936283

Czarnecki, Jan; Radoev, Boryan; Schramm, Laurier L; Slavchev, Radomir

2005-06-30

311

Western Gas Sands Project Status Report.  

National Technical Information Service (NTIS)

This edition of the WGSP status report summarizes September 1978 progress of the government-sponsored projects directed towards increasing gas production from the low-permeability gas sands of the western United States. Background information is provided ...

C. H. Atkinson

1978-01-01

312

Petrophysical Analysis of Oil Sand in Athabasca  

NASA Astrophysics Data System (ADS)

Oil sands are the major unconventional energy sources which have great reserves in Alberta, Canada. Recovery techniques such as CSS (Cyclic Steam Stimulation) and SAGD (Steam Assisted Gravity Drainage) enabled to develop deeper bitumen about several hundred meter depth. Before applying CSS and SAGD, reservoir heterogeneity of mud barriers or shale breccias should be clarified to establish injection and production wells successfully. We conducted the integrated petro-physical analysis for oil sands deposits in Athabasca by correlating well logs with seismic data. From 33 well logs and 3D seismic, we have made P-wave impedance by recursive inversion. Target formations of our analysis were the top of Wabiskaw member. Using inverted impedance and multi-attributes, porosity volume was derived at a target depth. Porosity of time slice 375 ms ranged 20 ~ 40 % stretching porous sand body from NE to SW direction. Characteristics of porosity distribution may be useful to design optimum oil sands recovery in Athabasca.

cheong, S.; Lee, H.

2013-12-01

313

Tight Gas Sands Log Interpretation: Problem Study.  

National Technical Information Service (NTIS)

A large undeveloped natural gas resource exists in low-permeability (tight) sandstone reservoirs. Difficulties in reservoir characterization and estimation of production potential in tight gas sands have hindered the development of this resource. Interpre...

C. L. Biddison E. R. Monson G. C. Kukal K. E. Simons R. E. Hill

1983-01-01

314

Recent activity in U. S. tar sand  

SciTech Connect

A review of the U.S. tar sand resources is presented. The total oil-in-place in 550 occurrences of tar sand in 22 states is estimated to be between 25 and 36 billion barrels, of which at least 80% is located in Utah. The lack of commercial oil production is attributed to the lack of proven technology, marketability of the produced oil, and a moratorium on leasing of federally controlled tar sand properties. Current activities to develop the U.S. tar sand resources include reservoir characterization and evaluation by industry, states, and DOE, oil recovery research by industry and universities, and few field mini-tests and pilot work by industry and DOE.

Marchant, L.C. (U.S. Department of Energy, Laramie Energy Technology Center, Laramie, WY); Stosur, J.J. (U.S. Department of Energy, Germantown, MD); Cupps, C.Q.

1980-01-01

315

Survey and Study on Sand and Dirt.  

National Technical Information Service (NTIS)

The report describes the techniques of sampling and analyses of worldwide soil samples. The results demonstrate that there are considerable differences between the actual sand and dirt environment and that specified in the Military specification. Field re...

E. Kuletz H. C. Schafer

1971-01-01

316

The analysis of electrification in windblown sand  

NASA Astrophysics Data System (ADS)

Based on asymmetric contact, we present a contact electrification model of high-energy trapped holes which considered the plastic deformation of the contact process in a single normal collision to predict the contact electrification and the charge-to-mass ratio of sand particles. Furthermore, the contact electrification was measured using a charge collection method. Our results show that the charged species trapped in high-energy states of sand particles are positive holes, the predicted results agree well with our experiments qualitatively and quantitatively, the impacting velocity and the particle size are two important factors affecting the magnitude of the charge-to-mass ratio of sand particles, and the number of collisions also affects the charge-to-mass ratio of sand particles.

Bo, Tian-Li; Zhang, Huan; Hu, Wen-Wen; Zheng, Xiao-Jing

2013-12-01

317

Oil sands: resource, recovery, and industry  

SciTech Connect

An overview of the oil sand industry is presented, including a description of resources and technologies used for producing petroleum substitutes. The focus of the work is on the status and potential of developments in Canada (primarily Alberta) and the US (primarily Alabama, California, Kentucky, New Mexico, Texas, and Utah). Reserves are estimated at 1000 billion bbl in Canada and 30 billion bbl in the US. Characteristics of oil sand are discussed with regard to viscosity range, saturation, bulk density, porosity, and permeability. Oil sand processing methods also are described, including in situ recovery. Commercial projects for recovery and research thereon are listed, concluding that the use of oil sands resources is necessary in the drive to achieve energy independence from conventional oil supplies. 19 references.

Cox, C.H.; Baughman, G.L.

1980-07-01

318

Sand consolidation methods using adsorbable catalysts  

SciTech Connect

Methods are provided for selectively consolidating sand grains within a subterranean formation. First an acidic zirconium salt catalyst, such as ZrOCl/sub 2/, Zr(SO/sub 4/)/sub 2/, or ZrCl/sub 4/, is injected into the subterranean formation, wherein the acidic salt catalyst is adsorbed to the surface of the sand 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 sand grains. The polymerized resin serves to consolidate the surfaces of the sand 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 during the polymerization reaction.

Friedman, R. H.

1985-04-23

319

Guide to preparing SAND reports. Revision.  

National Technical Information Service (NTIS)

This guide contains basic information needed to produce a SAND report; its guidelines reflect DOE regulations and Sandia policy. The guide includes basic writing instructions in an annotated sample report; guidance for organization, format, and layout of ...

1995-01-01

320

Guide to preparing SAND reports. Revised.  

National Technical Information Service (NTIS)

This guide contains basic information needed to produce a SAND report. Its guidelines reflect DOE regulation and Sandia policy. The guide includes basic writing instructions in an annotated sample report; guidance for organization, format, and layout of r...

T. K. Locke

1996-01-01

321

Evaluation of Sand Resources, Atlantic Offshore, Delaware.  

National Technical Information Service (NTIS)

Lithologic logs from 268 vibracores taken from the Delaware Atlantic offshore were evaluated for sediment type and compatibility with historical beach sediment textures. A model of sand resource evaluation, known as stack-unit mapping (Kempton, 1981) was ...

K. K. McKenna K. W. Ramsey

2002-01-01

322

Sand Dunes: A Phenomenon Of Wind  

NSDL National Science Digital Library

This webpage from Wayne's Word provides information about the origin of sand dunes, forms of life present there, and the sounds produced by "booming" dunes. Numerous dunes in the United States are described and pictured.

2010-06-29

323

Modeling the response of shoreface-connected sand ridges to sand extraction on an inner shelf  

NASA Astrophysics Data System (ADS)

Shoreface-connected sand ridges are rhythmic bedforms that occur on many storm-dominated inner shelves. The ridges span several kilometers, are a few meters high, and they evolve on a timescale of centuries. A process-based model is used to gain a fundamental insight into the response of these ridges to extraction of sand. Different scenarios of sand extraction (depth, location, and geometry of the extraction area; multiple sand extractions) are imposed. For each scenario, the response timescale as well as the characteristics of the new equilibrium state are determined. Results show that ridges partially restore after extraction, i.e., the disturbed bathymetry recovers on decadal timescales. However, in the end, the ridge original sand volume is not recovered. Initially, most sand that accomplishes the infill of the pit originates from the area upstream of the extraction, as well as from the areas surrounding the pit. The contribution of the latter strongly decreases in the subsequent time period. Depending on the location of the pit, additional sand sources contribute: First, if the pit is located close to the downstream trough, the pit gains sand by reduction of sand transport from the ridge to this trough. Second, if the pit is located close to the adjacent outer shelf, the ridge recovery is stronger due to an import of sand from that area. Furthermore, pits that are located close to the nearshore zone have a weak recovery, deeper pits have longer recovery timescales, wide and shallow pits recover most sand, while multiple sand pits slow down the recovery process.

Nnafie, A.; de Swart, H. E.; Calvete, D.; Garnier, R.

2014-04-01

324

Modeling the response of shoreface-connected sand ridges to sand extraction on an inner shelf  

NASA Astrophysics Data System (ADS)

Shoreface-connected sand ridges are rhythmic bedforms that occur on many storm-dominated inner shelves. The ridges span several kilometers, are a few meters high, and they evolve on a timescale of centuries. A process-based model is used to gain a fundamental insight into the response of these ridges to extraction of sand. Different scenarios of sand extraction (depth, location, and geometry of the extraction area; multiple sand extractions) are imposed. For each scenario, the response timescale as well as the characteristics of the new equilibrium state are determined. Results show that ridges partially restore after extraction, i.e., the disturbed bathymetry recovers on decadal timescales. However, in the end, the ridge original sand volume is not recovered. Initially, most sand that accomplishes the infill of the pit originates from the area upstream of the extraction, as well as from the areas surrounding the pit. The contribution of the latter strongly decreases in the subsequent time period. Depending on the location of the pit, additional sand sources contribute: First, if the pit is located close to the downstream trough, the pit gains sand by reduction of sand transport from the ridge to this trough. Second, if the pit is located close to the adjacent outer shelf, the ridge recovery is stronger due to an import of sand from that area. Furthermore, pits that are located close to the nearshore zone have a weak recovery, deeper pits have longer recovery timescales, wide and shallow pits recover most sand, while multiple sand pits slow down the recovery process.

Nnafie, A.; de Swart, H. E.; Calvete, D.; Garnier, R.

2014-05-01

325

Laser Sintering of Silica Sand – Mechanism and Application to Sand Casting Mould  

Microsoft Academic Search

Silica sand is commonly used in the foundry industry. With a high melting point of 160° C, the silica sand is normally sintered in a high-temperature furnace. However, silica with contents of calcium, aluminium, magnesium, and chlorine, etc. can form low-melting point eutectics. Therefore, a relatively low-power laser can be used to sinter the silica sand directly. The investigation of

X. H. Wang; J. Y. H. Fuh; Y. S. Wong; Y. X. Tang

2003-01-01

326

Shock and release behaviour of sand  

NASA Astrophysics Data System (ADS)

A considerable body of knowledge exists on the shock properties of dry sand. However, capturing the release properties has proven experimentally complex, and currently little information exists on the topic. The measured Hugoniot and release behaviour from a number of experiments is presented, carried out with the aim of furthering understanding of the fundamental physics behind the unloading of dry sand from a shocked state.

Perry, J. I.; Braithwaite, C. H.; Taylor, N. E.; Jardine, A. P.

2014-05-01

327

Modeling surficial sand and gravel deposits  

USGS Publications Warehouse

Mineral-deposit models are an integral part of quantitative mineral-resource assessment. As the focus of mineral-deposit modeling has moved from metals to industrial minerals, procedure has been modified and may be sufficient to model surficial sand and gravel deposits. Sand and gravel models are needed to assess resource-supply analyses for planning future development and renewal of infrastructure. Successful modeling of sand and gravel deposits must address (1) deposit volumes and geometries, (2) sizes of fragments within the deposits, (3) physical characteristics of the material, and (4) chemical composition and chemical reactivity of the material. Several models of sand and gravel volumes and geometries have been prepared and suggest the following: Sand and gravel deposits in alluvial fans have a median volume of 35 million m3. Deposits in all other geologic settings have a median volume of 5.4 million m3, a median area of 120 ha, and a median thickness of 4 m. The area of a sand and gravel deposit can be predicted from volume using a regression model (log [area (ha)] =1.47+0.79 log [volume (million m3)]). In similar fashion, the volume of a sand and gravel deposit can be predicted from area using the regression (log [volume (million m3)]=-1.45+1.07 log [area (ha)]). Classifying deposits by fragment size can be done using models of the percentage of sand, gravel, and silt within deposits. A classification scheme based on fragment size is sufficiently general to be applied anywhere. ?? 1994 Oxford University Press.

Bliss, J. D.; Page, N. J.

1994-01-01

328

Dynamics of a Projectile Penetrating Sand  

Microsoft Academic Search

The experiment reported in this paper was designed to obtain data on the dynamics of a nonrotating, conical-nosed projectile penetrating randomly-packed sand. Position versus time measurements for the projectile in sand were obtained by means of a photographic-electronic chronograph developed for the purpose. The striking velocity v0 of all rounds was about 700 m?sec. The negative acceleration of a 5-in.

William A. Allen; Earle B. Mayfield; Harvey L. Morrison

1957-01-01

329

Laboratory evaluation of selected tar sand asphalts  

SciTech Connect

Three tar sand asphalts of similar grades prepared from one syncrude by three different refining methods were characterized by tests commonly used to specify paving asphalts together with certain special tests. Asphalt-aggregate mixtures were prepared using these asphalts and tested in the laboratory to determine strength stiffness stability, tensile properties, temperature effects and water susceptibility. Comparison of the tar sand asphalt properties to conventional petroleum asphalt properties reveal no striking differences.

Button, J.W.; Epps, J.A.; Gallaway, B.M.

1980-12-01

330

Fatal outcome of a sand aspiration  

Microsoft Academic Search

Although extensive deep aspiration of sand, gravel, or dirt is a very rare incident, its consequences may be severe ranging\\u000a from the necessity of immediate intensive care to death. Cases reported so far were due to external causes such as cave-ins,\\u000a near drowning, or being buried under sand masses. We report a case of a 2 1\\/2-year-old boy who ingested

M. Kettner; F. Ramsthaler; B. Horlebein; P. H. Schmidt

2008-01-01

331

Geometry and dynamics of deterministic sand piles  

SciTech Connect

We report a study of the relaxation process of Bak-Tang-Wiesenfeld's sand pile under uniform initial conditions. For most geometries and initial conditions the final states consist of intricate geometric patterns, some of which are self-similar. Even without randomness, the flow of sand during relaxation often displays 1/{ital f} behavior, and this arises from interactions between the diffusive flow and the development of the final pattern.

Liu, S.H.; Kaplan, T. (Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN (USA)); Gray, L.J. (Engineering Physics and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN (USA))

1990-09-15

332

GRI program for tight gas sands research  

SciTech Connect

GRI (Gas Research Institute) is proceeding with six projects for tight gas sands research, involving analyses for producing natural gas from tight blanket sands that are presently considered as non-commercial. The program plan is comprised of a sequence of projects relating to resource identification, formation evaluation, fluids and proppants investigations, fracture design, reservoir modeling, and staged field tests with technology transfer. This paper describes the philosophy, objective, and content of the GRI program plan. 1 ref.

O'Shea, P.A.; Murphy, W.O.

1982-01-01

333

Humate in coastal sands of northwest Florida  

Microsoft Academic Search

Layers of dune and beach sand along the north coast of the Gulf of Mexico are cemented or impregnated with a conspicuous dark-brown to black water-solute organic substance herein called humate. The humate-cemented sand, generally 6 inches to 3 feet thick but as much as 15 feet thick in some places, forms one or several irregular layers in the subsurfaces

V. E. Swanson; J. G. Palacas

1965-01-01

334

Mobilization of trichloroethene (TCE) during ethanol flooding in uniform and layered sand packs under confined conditions  

NASA Astrophysics Data System (ADS)

Five horizontal flow experiments were conducted in homogeneous and layered sand packs to evaluate the effectiveness of mobilization of trichloroethene (TCE) by ethanol flooding. A small quantity (5-7 mL) of pure TCE was injected into the center of each sand pack, and then horizontal ethanol floods were conducted at darcy velocities between 4 and 12 m d-1. Once ethanol contacted the region initially affected by TCE in uniform sand packs, rapid downward and upgradient flow of TCE occurred along sloping ethanol-water interfaces. In layered sand packs the bulk mobilization of TCE appeared to be associated more with phenomena resulting from interfacial tension reduction rather than with enhanced dissolution processes. Heterogeneities promoted a variety of bypassing and mixing phenomena that resulted in, but were not limited to, physical displacement of TCE at the edges of discrete fine-grained lenses due to localized confined flow conditions; upward migration of ethanol through finer-grained soils due to buoyancy; rapid downward mobilization of TCE; upgradient mobilization of TCE around heterogeneities; and migration of TCE into finer-grained soils at locations both upgradient and downgradient of the TCE source zone. Enhanced TCE dissolution was also observed.

Grubb, Dennis G.; Sitar, Nicholas

1999-11-01

335

1. SAND DRAINING & DRYING BUILDING (RIGHT), COVERED INCLINE CONVEYOR ...  

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

1. SAND DRAINING & DRYING BUILDING (RIGHT), COVERED INCLINE CONVEYOR (LOWER RIGHT) THAT EXTENDS TO THE SAND-SORTING BUILDING, AND REMAINS OF ORIGINAL (1917) WASHING, DRAINING & DRYING BUILDING (LEFT), VIEW LOOKING WEST FROM TOP OF SAND-SORTING BUILDING - Mill "C" Complex, Sand Draining & Drying Building, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

336

Interaction forces in bitumen extraction from oil sands  

Microsoft Academic Search

Water-based extraction process (WBEP) has been successfully applied to bitumen recovery from Athabasca oil sand ore deposits in Alberta. In this process, two essential steps are involved. The bitumen first needs to be “liberated” from sand grains, followed by “aeration” with air bubbles. Bitumen “liberation” from the sand grains is controlled by the interaction between the bitumen and sand grains.

Jianjun Liu; Zhenghe Xu; Jacob Masliyah

2005-01-01

337

Treatment Efficiencies of Slow Sand Filtration for Landscape Water  

Microsoft Academic Search

The performance of the slow sand filter was examined using the landscape water with the experimental period of 46 days. The filter installed was similar to the traditional slow sand filter; expect that the top 5-cm sand was changed to the quartz sand. In this study, the variations of the turbidity, COD, BOD and TN were measured based on the

Cui Li; Yifan Wu; Liangbo Zhang; Wen Liu

2010-01-01

338

2D Mesoscale Simulations of Projectile Penetration into Sand  

Microsoft Academic Search

Physical Phenomena governing projectile instabilities during penetration of granular media (e.g. sand) are not well understood. To gain insight into projectile -- granular media interactions, 2-D mesoscale simulations were performed to examine projectile penetration into sand targets with explicit representation of sand grains and representative porosities. The computational procedure used to generate a mesoscale representation of a sand target is

R. D. Teeter; S. K. Dwivedi; C. W. Felice; Y. M. Gupta

2007-01-01

339

Methanogenic potential of tailings samples from oil sands extraction plants  

Microsoft Academic Search

Approximately 20% of Canada's oil supply now comes from the extraction of bitumen from the oil sands deposits in northeastern Alberta. The oil sands are strip-mined, and the bitumen is typically separated from sand and clays by an alkaline hot water extraction process. The rapidly expanding oil sands industry has millions of cubic metres of tailings for disposal and large

Phillip M. Fedorak; Debora L. Coy; Myrna J. Salloum; Marvin J. Dudas

2002-01-01

340

Biodiversity assessment in the Oil Sands region, northeastern Alberta, Canada  

Microsoft Academic Search

The Oil Sands region of northeastern Alberta contains the world's largest reserves of oil, in the form of tar-sand. In the Oil Sands region, a large number of environmental impact assessments (EIAs) have been completed for approximately 20 oil sands projects in the past two decades. The EIA process here is unique, in that stakeholders in the region (First Nations,

Mark Sherrington

2005-01-01

341

WITSEG sampler: a segmented sand sampler for wind tunnel test  

Microsoft Academic Search

The flux profile of blowing sand is the reflection of a large number of sand particles moving in different trajectories. To describe the function of the flux profile requires measuring the flux of blown sand at different heights. A segmented sand sampler for wind tunnel study (WITSEG sampler) has been designed and evaluated in a wind tunnel. The sampler is

Zhibao Dong; Hongyi Sun; Aiguo Zhao

2004-01-01

342

Optical Dating of Tsunami-Laid Sands  

NASA Astrophysics Data System (ADS)

The ages of some tsunami deposits can be determined by optical dating, a key requirement being that the deposits are derived from sediment that was reworked and exposed to daylight by tidal currents, waves, wind, or bioturbation during the last years before the tsunami. Measurements have been made using 1.4 eV (infrared) excitation of K-feldspar grains separated from samples of prehistoric tsunami sand sheets and modern analogs of tsunami source sediments at four sites in Washington state and British Columbia. Source sands gave equivalent doses indicative of recent exposure to daylight. Tsunami sand at Cultus Bay, Washington, yielded an optical age of 1285 ± 95 yr (calendric years before A.D. 1995, ±1?). At 2?, this age overlaps the range of from 1030 to 1100 yr determined through a combination of high-precision radiocarbon dating and stratigraphic correlation. Tsunami sands at three sites near Tofino and Port Alberni on Vancouver Island, British Columbia, have optical ages of 260 ± 20, 325 ± 25, and 335 ± 45 yr. Historical records and radiocarbon dating show that the sand at each of the three sites is between 150 and 400 yr old. These optical ages support the hypothesis that the Vancouver Island sands were deposited by a tsunami generated by a large earthquake on the Cascadia subduction zone about 300 yr ago.

Huntley, David J.; Clague, John J.

1996-09-01

343

History of development and depositional environment and upper Cherokee Prue Sand, Custer and Roger Mills counties, Oklahoma  

SciTech Connect

In western Oklahoma the uppermost sand member of the Cherokee Group, the True sand, was first drilled and found productive in two discoveries, completed in 1980, in west-central Custer County and in central Roger Mills County, Oklahoma. For 1 1/2 to 2 years these two discoveries, some 18 mi (29 km) apart, were thought to be stratigraphic equivalents of two separate sand bodies occurring parallel to the classic northwest-southeast-trending systems of the Anadarko basin. At present, some 40 productive wells will ultimately produce more than 100 bcf of gas and 3 million bbl of condensate from an average depth of 11,500 ft (3500 m). Sand porosities range from 3 to 18% with most producing wells having porosities in the 12 to 15% range. Because Prue sand is slightly overpressured (a pressure gradient of .53 psi/foot), the reserves are generally better than normal-pressured wells at this depth. The sand body is over 40 mi (64 km) in length, 1 to 1.5 mi (1.6 to 2.4 km) wide, and 60 ft (18 m) thick. Study of the core shows the interval to grade from a medium to fine-grained sand, highly laminated and cross-bedded with black shale, to a slightly coarser grained nonstructured interval and back into a highly laminated cross-bedded sandy black shale interval. The interval is topped by a 10 ft (3 m) thick black shale layer that is a predominant bed throughout the whole area. These conclusions have implications that may assist in the exploration of other Pennsylvanian sands in this area.

Baumann, D.K.; Peterson, M.L.; Hunter, L.W.

1983-03-01

344

Morphology and formation of the upwind margin at White Sands Dune Field  

NASA Astrophysics Data System (ADS)

A remarkable transitional landscape occurs at the upwind margin of White Sands Dune Field. Over the course a few hundred meters the landscape changes from an flat, sand availability-limited playa, to a sand sheet with strong spatial grain-size sorting, to meter high slipfaceless proto-dunes and finally to several meter high dunes with angle-of-repose slip faces. Within one wavelength of the first dune, dunes rise to nearly 10 meters in height above Alkali Flat, the upwind playa that extends for 13 km westward from the dune field. This abrupt rise in topography may perturb the dominant southwesterly wind flow and trigger an internal boundary layer, which causes a spatial decrease in surface wind stress and decline sediment flux, thereby altering the dune dynamics and dune field morphology downwind. Though the emergence of this upwind transition may play a key role in the morphodynamics of the dune field, what are the morphodynamics of the transition? What are the feedbacks between the emerging topography and the wind within the transition? This presentation uses high-resolution aerial photos, time-series airborne LiDAR and terrestrial laser scanning to characterize the transitional morphology the upwind margin of White Sands and discusses these morphologies in the context of the interplay between wind flow and dune field topography. Alkali Flat playa is sparsely sand covered, the amount of which varies temporally. The sparse sand cover occurs as sand patches that form in the lee of bushes or within topographic lows generated by deflated gypsum crust. Adjacent and downwind of the playa is a sand sheet composed of variable wavelength, coarse grained ripples. Ten to thirty meter wide ripple patches organized into a repeating sequence of coarse-grained, > 15 cm wavelength ripples to fine-grained, < 15 cm wavelength ripples occur across the sand sheet. Downwind the ripple patches organize into low-relief protodune hummocks. The protodunes are covered by a range of ripple sizes that are spatially organized similar to the ripple patches within the sand sheet. The coarsest-grained, largest wavelength ripples occur at the protodune crest and fine downwind. The inter-protodune areas are typically free of sand, exposing indurated dune stratigraphy. The protodunes grow in height, but the wavelength remains ~ 70 m downwind until a slipface develops. Rapid growth into 5-10 meter high dunes occurs within one wavelength after slipface development and generates an abrupt topographic increase in topography. Dune migration rates are approximately 6 m/year at the upwind margin and decline to around 3 m/year within a few kilometers of the upwind margin. A generalized model of dune emergence at the upwind margin of dune fields is proposed using examples from other dune fields.

Ewing, R. C.; Jerolmack, D. J.; Martin, R. L.; Reitz, M. D.; Phillips, C. B.; Falcini, F.; Masteller, C.

2012-12-01

345

The application of power ultrasound to the surface cleaning of silica and heavy mineral sands.  

PubMed

Power ultrasound may be used in the processing of minerals to clean their surfaces of oxidation products and fine coatings, mainly through the large, but very localised, forces produced by cavitation. Results of the application of power ultrasound to remove iron-rich coatings from the surfaces of silica sand used in glass making and to improve the electrostatic separation of mineral sand concentrates through lowering the resistivity of the conducting minerals (ilmenite and rutile) are presented. Parameters affecting ultrasonic cleaning, such as input power and levels of reagent addition, are discussed. In particular, we present data showing the relationship between power input and the particle size of surface coatings removed. This can be explained by the Derjaguin approximation for the energy of interaction between a sphere and a flat surface. PMID:11062883

Farmer, A D; Collings, A F; Jameson, G J

2000-10-01

346

Provenance and recycling of Arabian desert sand  

NASA Astrophysics Data System (ADS)

This study seeks to determine the ultimate origin of aeolian sand 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 sands from the Red 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 sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand 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 sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand 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 sand, 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 sands, 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 sand, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.

Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

2013-05-01

347

Provenance and recycling of Arabian desert sand  

NASA Astrophysics Data System (ADS)

This study seeks to determine the ultimate origin of aeolian sand 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 sands from the Red 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 sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand 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 sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand 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 sand, 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 sands, 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 sand, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.

Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid; Al-Juboury, Ali

2013-04-01

348

United states tar sands as a petroleum source  

Microsoft Academic Search

This discussion of the U.S. tar sand deposits includes the following topics: geographic and geologic distribution, tar sand host rocks, impregnating material, a comparison between the U.S. and Canadian deposits, thermal recovery of tar sands, recent U.S. tar sand mining and separation experience, and price and incentives. Several U.S. tar sand deposits compare favorably with Athabasca in having big reserves

Ball

1967-01-01

349

Two-region flow and decreased sorption of uranium (VI) during transport in Hanford groundwater and unsaturated sands  

Microsoft Academic Search

Uranium, U(VI), sorption and transport in unsaturated coarse-and fine-textured sands were evaluated using a centrifuge method; batch incubation and saturated column experiments were conducted to isolate the effect of flow from that of water content. At higher water contents (>=66% saturation), decreases in U(VI) sorption were due to rate limitations. These breakthrough curves (BTCs) were well characterized with a two-site

A. P. Gamerdinger; D. I. Kaplan; D. M. Wellman; R. J. Serne

2001-01-01

350

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

351

Applying NMR spin-echo logging to Shaly Sand Formation evaluation: Case studies of Rocky Mountain region gas wells  

Microsoft Academic Search

Conventional wireline logs often fail to provide a reliable evaluation of reservoir quality and producibility in shaly mud formations, particularly in the shaly gas sand reservoirs of the Rocky Mountains which are characterized by low porosity (i.e., <15 pu), low permeability (0.1 to 1 md), very fine grain size, and high irreducible water saturations. A new-generation nuclear magnetic resonance (NMR)

R. K. Ladtkow; B. J. Stambaugh; D. Mardon

1995-01-01

352

Advanced characterisation of organic matter in oil sands and tailings sands used for land reclamation by Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS)  

NASA Astrophysics Data System (ADS)

The Athabasca region of northern Alberta, Canada, is home to deposits of oil sands containing vast amounts (~ 173 billion barrels) of heavily biodegraded petroleum. Oil sands are recovered by surface mining or by in situ steam injection. The extraction of bitumen from oil sands by caustic hot water processing results in large volumes of fluid tailings, which are stored in on-site settling basins. There the tailings undergo a compaction and dewatering process, producing a slowly densifying suspension. The released water is recycled for extraction. The fine tailings will be reclaimed as either dry or wet landscapes. [1] To produce 1 barrel of crude oil, 2 tons of oil sand and 2 - 3 tons of water (including recycled water) are required. [2] Open pit mining and the extraction of the bitumen from the oil sands create large and intense disturbances of different landscapes. The area currently disturbed by mining operations covers about 530 km2 and the area of tailing ponds surpasses 130 km2. An issue of increasing importance is the land remediation and reclamation of oil sand areas in Canada and the reconstruction of these disturbed landscapes back to working ecosystems similar to those existing prior to mining operations. An important issue in this context is the identification of oil sand-derived organic compounds in the tailings, their environmental behaviour and the resulting chances and limitations with respect to land reclamation. Furthermore the biodegradation processes that occur in the tailings and that could lead to a decrease in hazardous organic compounds are important challenges, which need to be investigated. This presentation will give a detailed overview of our compositional and quantitative characterisation of the organic matter in oil sand, unprocessed and processed mature fine tailings samples as well as in tailings sands used as part of land reclamation. The analytical characterisation is based on the extraction of the soluble organic matter, its subsequent separation into asphaltenes, aliphatic hydrocarbons, aromatic hydrocarbons, neutral nitrogen, sulphur, oxygen (NSO) compounds and carboxylic acids. The asphaltene fractions are analysed using pyrolysis-GC, all other fractions are analysed by GC-MS. Additionally Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) is used to study the chemical composition of the samples on the molecular level using different ionisation methods.

Noah, M.; Vieth-Hillebrand, A.; Wilkes, H.

2012-04-01

353

Mechanical Response of Dry Reid-Bedford Model Sand and Saturated Misers Bluff Sand.  

National Technical Information Service (NTIS)

This report presents a collection of data from laboratory mechanical property tests on dry Reid-Bedford Model sand and saturated MISERS BLUFF sand which were conducted by the US Army Engineer Waterways Experiment Station in support of a variety of project...

B. R. Phillips

1986-01-01

354

Bright sand/dark dust: The identification of active sand surfaces on the Earth and Mars  

NASA Technical Reports Server (NTRS)

Field studies and analysis of LANDSAT Thematic Mapper data in the Gran Desierto, Mexico may shed light on a technique to distinguish active from inactive (relict) sand surfaces. Active sand bodies in the study area are consistently brighter (by an average of 20%) at visual and near infrared wavelengths and darker at thermal infrared wavelengths than compositionally similar inactive sands. The reasons for the albedo difference between active and inactive sands are reviewed and the mixing model of Johnson et al. is examined for tracing the provenance of sands based on albedo and spectral variations. Portions of the wavelengths covered by the Mars Orbiter correspond to the Thematic Mapper data. The identification of active sands on Earth, with a priori knowledge of bulk composition and grain size distribution, may allow the remote mapping of active sand surfaces on Mars. In conjuction with thermal infrared remote sensing for composition, it may also provide a method for the remote determination of grain size distributions within sand/silt mixtures.

Blount, H. G., II; Greeley, R.; Christensen, P. R.; Arvidson, R.

1987-01-01

355

Bright sand/dark dust: The identification of active sand surfaces on the Earth and Mars  

NASA Astrophysics Data System (ADS)

Field studies and analysis of LANDSAT Thematic Mapper data in the Gran Desierto, Mexico may shed light on a technique to distinguish active from inactive (relict) sand surfaces. Active sand bodies in the study area are consistently brighter (by an average of 20%) at visual and near infrared wavelengths and darker at thermal infrared wavelengths than compositionally similar inactive sands. The reasons for the albedo difference between active and inactive sands are reviewed and the mixing model of Johnson et al. is examined for tracing the provenance of sands based on albedo and spectral variations. Portions of the wavelengths covered by the Mars Orbiter correspond to the Thematic Mapper data. The identification of active sands on Earth, with a priori knowledge of bulk composition and grain size distribution, may allow the remote mapping of active sand surfaces on Mars. In conjuction with thermal infrared remote sensing for composition, it may also provide a method for the remote determination of grain size distributions within sand/silt mixtures.

Blount, H. G., II; Greeley, R.; Christensen, P. R.; Arvidson, R.

1987-05-01

356

Wind tunnel experimental investigation of sand velocity in aeolian sand transport  

NASA Astrophysics Data System (ADS)

Sand velocity in aeolian sand transport was measured using the laser Doppler technique of PDPA (Phase Doppler Particle Analyzer) in a wind tunnel. The sand velocity profile, probability distribution of particle velocity, particle velocity fluctuation and particle turbulence were analyzed in detail. The experimental results verified that the sand horizontal velocity profile can be expressed by a logarithmic function above 0.01 m, while a deviation occurs below 0.01 m. The mean vertical velocity of grains generally ranges from - 0.2 m/s to 0.2 m/s, and is downward at the lower height, upward at the higher height. The probability distributions of the horizontal velocity of ascending and descending particles have a typical peak and are right-skewed at a height of 4 mm in the lower part of saltation layer. The vertical profile of the horizontal RMS velocity fluctuation of particles shows a single peak. The horizontal RMS velocity fluctuation of sand particles is generally larger than the vertical RMS velocity fluctuation. The RMS velocity fluctuations of grains in both horizontal and vertical directions increase with wind velocity. The particle turbulence intensity decreases with height. The present investigation is helpful in understanding the sand movement mechanism in windblown sand transport and also provides a reference for the study of blowing sand velocity.

Kang, Liqiang; Guo, Liejin; Gu, Zhengmeng; Liu, Dayou

2008-05-01

357

Visualization and laser measurements on the flow field and sand movement on sand dunes with porous fences  

Microsoft Academic Search

The installation of windbreak sand fences around sand dunes is one of the most promising methods to suppress windblown sand\\u000a movement. In the study reported in this paper, we investigated the influence and validity of a small fence mounted on a model\\u000a sand dune, in order to understand the fence’s suppression mechanism on the sand movement. The flow field around

Takahiro Tsukahara; Yusuke Sakamoto; Daisuke Aoshima; Makoto Yamamoto; Yasuo Kawaguchi

2011-01-01

358

MAHLI at the Rocknest sand shadow: Science and science-enabling activities  

NASA Astrophysics Data System (ADS)

Martian solar days 57-100, the Mars Science Laboratory Curiosity rover acquired and processed a solid (sediment) sample and analyzed its mineralogy and geochemistry with the Chemistry and Mineralogy and Sample Analysis at Mars instruments. An aeolian deposit—herein referred to as the Rocknest sand shadow—was inferred to represent a global average soil composition and selected for study to facilitate integration of analytical results with observations from earlier missions. During first-time activities, the Mars Hand Lens Imager (MAHLI) was used to support both science and engineering activities related to sample assessment, collection, and delivery. Here we report on MAHLI activities that directly supported sample analysis and provide MAHLI observations regarding the grain-scale characteristics of the Rocknest sand shadow. MAHLI imaging confirms that the Rocknest sand shadow is one of a family of bimodal aeolian accumulations on Mars—similar to the coarse-grained ripples interrogated by the Mars Exploration Rovers Spirit and Opportunity—in which a surface veneer of coarse-grained sediment stabilizes predominantly fine-grained sediment of the deposit interior. The similarity in grain size distribution of these geographically disparate deposits support the widespread occurrence of bimodal aeolian transport on Mars. We suggest that preservation of bimodal aeolian deposits may be characteristic of regions of active deflation, where winnowing of the fine-sediment fraction results in a relatively low sediment load and a preferential increase in the coarse-grained fraction of the sediment load. The compositional similarity of Martian aeolian deposits supports the potential for global redistribution of fine-grained components, combined with potential local contributions.

Minitti, M. E.; Kah, L. C.; Yingst, R. A.; Edgett, K. S.; Anderson, R. C.; Beegle, L. W.; Carsten, J. L.; Deen, R. G.; Goetz, W.; Hardgrove, C.; Harker, D. E.; Herkenhoff, K. E.; Hurowitz, J. A.; Jandura, L.; Kennedy, M. R.; Kocurek, G.; Krezoski, G. M.; Kuhn, S. R.; Limonadi, D.; Lipkaman, L.; Madsen, M. B.; Olson, T. S.; Robinson, M. L.; Rowland, S. K.; Rubin, D. M.; Seybold, C.; Schieber, J.; Schmidt, M.; Sumner, D. Y.; Tompkins, V. V.; Van Beek, J. K.; Van Beek, T.

2013-11-01

359

Effect of proppant failure and fines migration on conductivity of propped fractures  

SciTech Connect

Long-term conductivity testing at realistic environmental conditions has greatly improved the measurement of proppant pack permeability. However, the use of low flow rates to insure Darcy flow in such measurements has masked the total effect of failed proppant fines on proppant pack permeability. As flow rates increase, corresponding with those commonly found in the field, fines are mobilized and migrate into new positions that reduce the permeability of the proppant pack beyond that normally observed in conductivity measurements. This effect has generally been overlooked in proppant pack design. This paper examines the extent of conductivity reduction caused by migrating proppant fines and the effect of proppant type on the extent of that reduction. The role of fines migration on the conductivity of proppant packs containing two different types of proppants, where the more capable proppant is used near the wellbore, is also evaluated. Representative commercially available proppants, including sand, resin-coated sand, and low density ceramics are included in the study.

Gidley, J.L. (John L. Gidley and Associates, Inc., Houston, TX (United States)); Penny, G.S. (Stim-Lab. Inc., Duncan, OK (United States)); McDaniel, R.R.

1995-02-01

360

The application of baghouse fines in Taiwan  

Microsoft Academic Search

Strict environmental regulations in Taiwan require baghouse fines (BHFs) to be collected during hot mix asphalt production. In an attempt to utilize this byproduct, baghouse fines have been incorporated into asphalt concrete mixtures, which were applied to county roads and other light traffic roads despite a lack of research. This study examines 14 types of fines, including 9 baghouse fines,

Deng-Fong Lin; Jyh-Dong Lin; Shun-Hsing Chen

2006-01-01

361

Spearfish water sand: an overlooked play  

SciTech Connect

The Waskada-Pierson plays in the Amaranth Formation in southern Manitoba have prompted a study of similar units in Bottineau County, north-central North Dakota. The pay zone in the Waskada field is a sequence of sandstones and siltstones trapping oil which has migrated from the underlying Mississippian strata. The Triassic Spearfish Formation of North Dakota, correlative with the Amaranth Formation of Manitoba, consists of a similar sequence of interbedded sandstones and siltstones which unconformably overlie carbonate and anhydrite rocks of the Madison Group. Log characteristics show the sandstone and siltstones of this sequence to be laterally continuous over the study area. Except for one well, production in the Bottineau area of North Dakota has been confined to either a portion of the Madison Group or a basal Spearfish sand. This basal sand is overlain by a 20 to 25-ft (6 to 7-m) thick impermeable siltstone which acts as a vertical seal for the Newburg/South Westhope pay. Above this siltstone is a unit locally known as the Spearfish water sand, a water-bearing sandstone in the Newburg/South Westhope fields. The one exception to basal Spearfish production is located in Sec. 6, T163N, R78W, where the Cardinal Petroleum 1 Oscar Aftem well has been producing from the Spearfish water sand since December 1961, indicating that the water sand may have potential for more production in the area.

Lefever, J.A.; Anderson, S.B.; Lefever, R.D.

1983-08-01

362

Gas fluidized sand, liquid or solid?  

NASA Astrophysics Data System (ADS)

If one can measure flow properties of a granular material which are very reminiscent of a simple liquid, it would instill confidence that a relatively simple granular fluid mechanical model may exist. A granular fluid very reminiscent of a simple liquid is gas fluidized sand. Such sand can be easily stirred regardless of depth beneath the surface. In order to test the fluid like behavior more rigorously we have performed a series of experiments on the drag force on a ball moving vertically through the sand. At low fluidization rates (non bubbling) we have found that a brass sphere will sink only to a certain depth at which point its weight is entirely supported by the sand. Deeper yet, the sphere again moves freely. When pressure is applied to the top of the bed, this solid like layer can be moved closer to the top surface of the bed. These measurements were performed at flow rates where light scattering studies have shown all the grains to be motionless. Our experiments suggest that gas fluidized sand shows more complexity than a solid with very a very low yield stress. We thank the NSF-REU program for partial support of this research.

Stoker, David S.; Rutgers, Maarten A.

2000-03-01

363

Biogeochemical pathways that influence de-watering and consolidation of fluid fine tailings  

NASA Astrophysics Data System (ADS)

Approximately 1 million m3 of fluid fine tailings are produced every day in northern Alberta, Canada from processing of surface-mined oil sands resources. The tailings, comprising an aqueous suspension of fines dominated by clay particles that remain dispersed for decades, are deposited into tailings ponds for containment, de-watering and consolidation. Slow consolidation of clays retained in tailings ponds hinders recovery and re-use of water, retards volume reduction and presents a technical challenge for effective tailings ponds management. Here, we reveal that microorganisms indigenous to oil sands tailings ponds change the surface chemistry of clay particles and accelerate tailings consolidation by two biogeochemical pathways: one pathway shows that microorganisms metabolize organic substrates and produce carbon dioxide (CO2) and methane (CH4) in oil sands tailings. Dissolution of biogenic CO2 increases bicarbonate (HCO3-) concentrations in the pore water and reduces pore water pH, which dissolves carbonate minerals and releases cations from tailings minerals. The higher ionic strength of the pore water resulting from increased concentrations of ions shrinks the double diffuse layers of clay particles and hence increases consolidation. In addition, biogenic CH4 ebullition creates transient physical channels for recovery of pore water. The second pathway exerts a more direct microbial effect on consolidation through transformation of iron (Fe) minerals in oil sands tailings. Microbial reduction and dissolution of FeIII minerals forms amorphous FeII minerals that entrap and mask electronegative clay surfaces. These biogeochemical processes provide essential information for construction of geotechnical models to predict settling of clay particles for effective reclamation and management of fluid fine tailings.

Siddique, T.; Foght, J.

2013-12-01

364

Prediction of sedimentation and consolidation of fine tails  

SciTech Connect

Sedimentation and consolidation of suspensions of fine particles were analyzed by integrating experimental measurement of properties in a centrifuge with a comprehensive numerical model. The yield stress and settling velocity for tailings from tar sands extraction were determined experimentally as a function of the volume fraction of solids. The evaluated state functions were used to simulate batch settling and consolidation, and the results compare well with long-term settling tube tests. This approach is very attractive where gravity sedimentation may take many years, and it allows prediction of the rate of clear water production, total time for sedimentation and consolidation, and the maximum concentration of solids. Scaling of the sedimentation between centrifuge and field conditions is discussed. Conversion of permeability-void ratio relationships from geotechnical experiments to state functions of hindered settling velocity is demonstrated, allowing the use of data derived from a variety of experimental techniques.

Eckert, W.F.; Masliyah, J.H.; Gray, M.R.; Fedorak, P.M. [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical Engineering] [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical Engineering

1996-04-01

365

Surface sediments of transboundary Lake Peipsi: composition, dynamics and role in matter cycling  

Microsoft Academic Search

To describe and analyse the role of sediments in the matter cycling in large shallow transboundary Lake Peipsi (L. Peipsi)\\u000a in north-eastern Europe, detailed surface-sediment mapping was conducted. On the basis of grain size the surface sediments\\u000a fall into three groups: coarse-grained sediments (prevailingly sands in the lake’s southern part), fine-grained sediments\\u000a (mainly silts) and silty sands, both in the

Jaan-Mati Punning; Anto Raukas; Jaanus Terasmaa; Tiit Vaasma

2009-01-01

366

Occurrence of gas hydrate in Oligocene Frio sand: Alaminos Canyon Block 818: Northern Gulf of Mexico  

SciTech Connect

A unique set of high-quality downhole shallow subsurface well log data combined with industry standard 3D seismic data from the Alaminos Canyon area has enabled the first detailed description of a concentrated gas hydrate accumulation within sand in the Gulf of Mexico. The gas hydrate occurs within very fine grained, immature volcaniclastic sands of the Oligocene Frio sand. Analysis of well data acquired from the Alaminos Canyon Block 818 No.1 ('Tigershark') well shows a total gas hydrate occurrence 13 m thick, with inferred gas hydrate saturation as high as 80% of sediment pore space. Average porosity in the reservoir is estimated from log data at approximately 42%. Permeability in the absence of gas hydrates, as revealed from the analysis of core samples retrieved from the well, ranges from 600 to 1500 millidarcies. The 3-D seismic data reveals a strong reflector consistent with significant increase in acoustic velocities that correlates with the top of the gas-hydrate-bearing sand. This reflector extends across an area of approximately 0.8 km{sup 2} and delineates the minimal probable extent of the gas hydrate accumulation. The base of the inferred gas-hydrate zone also correlates well with a very strong seismic reflector that indicates transition into units of significantly reduced acoustic velocity. Seismic inversion analyses indicate uniformly high gas-hydrate saturations throughout the region where the Frio sand exists within the gas hydrate stability zone. Numerical modeling of the potential production of natural gas from the interpreted accumulation indicates serious challenges for depressurization-based production in settings with strong potential pressure support from extensive underlying aquifers.

Boswell, R.D.; Shelander, D.; Lee, M.; Latham, T.; Collett, T.; Guerin, G.; Moridis, G.; Reagan, M.; Goldberg, D.

2009-07-15

367

Sliding Friction on Wet and Dry Sand  

NASA Astrophysics Data System (ADS)

We show experimentally that the sliding friction on sand is greatly reduced by the addition of some—but not too much—water. The formation of capillary water bridges increases the shear modulus of the sand, which facilitates the sliding. Too much water, on the other hand, makes the capillary bridges coalesce, resulting in a decrease of the modulus; in this case, we observe that the friction coefficient increases again. Our results, therefore, show that the friction coefficient is directly related to the shear modulus; this has important repercussions for the transport of granular materials. In addition, the polydispersity of the sand is shown to also have a large effect on the friction coefficient.

Fall, A.; Weber, B.; Pakpour, M.; Lenoir, N.; Shahidzadeh, N.; Fiscina, J.; Wagner, C.; Bonn, D.

2014-05-01

368

UV disinfection for onsite sand filter effluent  

SciTech Connect

The technical and economic feasibility of using ultraviolet (uv) light as a viable alternative to chlorine as the required disinfectant for onsite sand filter effluents discharged to surface waters in Maine was determined. To obtain a reliable cross section of performance for sand filters in Maine, 74 filters were selected for an effluent characterization program. The effluent characterization study allowed general conclusions to be made with regard to the potential of uv disinfection. A simple suspended lamp uv disinfection unit was designed, constructed, and tested in the laboratory and in the field. The efficiency of the uv disinfection unit was determined through field testing at 10 of the 74 sand filter sites used in the effluent characterization program.

Lowery, J.D.; Romatzick, S.

1982-05-01

369

Sliding friction on wet and dry sand.  

PubMed

We show experimentally that the sliding friction on sand is greatly reduced by the addition of some-but not too much-water. The formation of capillary water bridges increases the shear modulus of the sand, which facilitates the sliding. Too much water, on the other hand, makes the capillary bridges coalesce, resulting in a decrease of the modulus; in this case, we observe that the friction coefficient increases again. Our results, therefore, show that the friction coefficient is directly related to the shear modulus; this has important repercussions for the transport of granular materials. In addition, the polydispersity of the sand is shown to also have a large effect on the friction coefficient. PMID:24836256

Fall, A; Weber, B; Pakpour, M; Lenoir, N; Shahidzadeh, N; Fiscina, J; Wagner, C; Bonn, D

2014-05-01

370

Flocculation settling characteristics of mud: sand mixtures  

NASA Astrophysics Data System (ADS)

When natural muds become mixed with sandy sediments in estuaries, it has a direct effect on the flocculation process and resultant sediment transport regime. Much research has been completed on the erosion and consolidation of mud/sand mixtures, but very little is known quantitatively about how mixed sediments interact whilst in suspension, particularly in terms of flocculation. This paper presents the settling velocity findings from a recent laboratory study which examined the flocculation dynamics for three different mud/sand mixtures at different concentrations (0.2-5 g.l-1) and turbulent shear stresses (0.06-0.9 Pa) in a mini-annular flume. The low intrusive video-based Laboratory Spectral Flocculation Characteristics instrument was used to determine floc/aggregate properties (e.g., size, settling velocity, density and mass) for each population. Settling data was assessed in terms of macrofloc (>160 ?m) and microfloc (<160 ?m) settling parameters: Wsmacro and Wsmicro, respectively. For pure muds, the macroflocs are regarded as the most dominant contributors to the total depositional flux. The parameterised settling data indicates that by adding more sand to a mud/sand mixture, the fall velocity of the macrofloc fraction slows and the settling velocity of microflocs quickens. Generally, a mainly sandy suspension comprising 25% mud and 75% sand (25M:75S), will produce resultant Wsmacro which are slower than Wsmicro. The quickest Wsmicro appears to consistently occur at a higher level of turbulent shear stress (? ˜ 0.6 Pa) than both the macrofloc and microfloc fractions from suspensions of pure natural muds. Flocculation within a more cohesively dominant muddy-sand suspension (i.e., 75M:25S) produced macroflocs which fell at similar speeds (±10%) to pure mud suspensions at both low (200 mg l-1) and intermediate (1 g l-1) concentrations at all shear stress increments. Also, low sand content suspensions produced Wsmacro values that were faster than the Wsmicro rates. In summary, the experimental results of the macrofloc and microfloc settling velocities have demonstrated that flocculation is an extremely important factor with regards to the depositional behaviour of mud/sand mixtures, and these factors must be considered when modelling mixed sediment transport in the estuarine or marine environment.

Manning, Andrew J.; Baugh, John V.; Spearman, Jeremy R.; Whitehouse, Richard J. S.

2010-04-01

371

Environmental differences in substrate mechanics do not affect sprinting performance in sand lizards (Uma scoparia and Callisaurus draconoides).  

PubMed

Running performance depends on a mechanical interaction between the feet of an animal and the substrate. This interaction may differ between two species of sand lizard from the Mojave Desert that have different locomotor morphologies and habitat distributions. Uma scorparia possesses toe fringes and inhabits dunes, whereas the closely related Callisaurus draconoides lacks fringes and is found on dune and wash habitats. The present study evaluated whether these distribution patterns are related to differential locomotor performance on the fine sand of the dunes and the course sand of the wash habitat. We measured the kinematics of sprinting and characterized differences in grain size distribution and surface strength of the soil in both habitats. Although wash sand had a surface strength (15.4±6.2 kPa) that was more than three times that of dune sand (4.7±2.1 kPa), both species ran with similar sprinting performance on the two types of soil. The broadly distributed C. draconoides ran with a slightly (22%) faster maximum speed (2.2±0.2 m s(-1)) than the dune-dwelling U. scorparia (1.8±0.2 m s(-1)) on dune sand, but not on wash sand. Furthermore, there were no significant differences in maximum acceleration or the time to attain maximum speed between species or between substrates. These results suggest that differences in habitat distribution between these species are not related to locomotor performance and that sprinting ability is dominated neither by environmental differences in substrate nor the presence of toe fringes. PMID:21147976

Korff, Wyatt L; McHenry, Matthew J

2011-01-01

372

Method for cleaning fine coal  

Microsoft Academic Search

A method for cleaning fine coal is provided which includes: mixing the coal with a fluid of such a specific gravity that clean coal particles would float while refuse particles would sink therein, pretreating the coalfluid slurry by adding a surfactant, subjecting the mixture to ultrasonic dispersion, and separating the entire mixture into higher and lower specific gravity fluid streams

Smit

1985-01-01

373

Thermoremanent Magnetization of Fine Powders  

Microsoft Academic Search

This is a brief explanation of the magnetic properties of fine ferromagnetic grains of single elementary domains, especially in reference to the influence of time on the magnetization at a given temperature. Application is made to the interpretation of the thermoremanent magnetization of lavas and clays and to the determination of the direction and intensity of the terrestrial magnetic field

Louis Néel

1953-01-01

374

Fine Arts. [SITE 2002 Section].  

ERIC Educational Resources Information Center

This document contains two papers on fine arts from the SITE (Society for Information Technology & Teacher Education) 2002 conference. "Expanding the Boundaries of the Music Education of the Elementary Teacher Classroom with Information Technology" (Cheryl Jackson) reports on how information technology is used in a music methods course for…

Robin, Bernard, Ed.

375

SOUTHERN FINE PARTICULATE MONITORING PROJECT  

SciTech Connect

This is the second quarterly progress report of the ''Southern Fine Particulate Monitoring Project'', funded by the U.S. Department of Energy's National Energy Technology Laboratory under DOE Cooperative Agreement No. DE-FC26-00NT40770 to Southern Research Institute (SRI). In this two year project SRI will conduct detailed studies of ambient fine particulate matter in the Birmingham, AL metropolitan area. Project objectives include: Augment existing measurements of primary and secondary aerosols at an established urban southeastern monitoring site; Make a detailed database of near-continuous measurements of the time variation of fine particulate mass, composition, and key properties (including particle size distribution); Apply the measurements to source attribution, time/transport properties of fine PM, and implications for management strategies for PM{sub 2.5}; and Validate and compare key measurement methods used in this study for applicability within other PM{sub 2.5} research by DOE-FE, EPA, NARSTO, and others.

Ashley D. Williamson

2001-04-01

376

Fine Arts in the Curriculum.  

ERIC Educational Resources Information Center

In this anthology the issues related to the fine arts (music, theater, visual arts) in the elementary secondary curriculum are examined. The fifteen articles, ranging in length from one to seven pages, are followed by a biographical page briefly identifying the contributors. The articles are: "What's It All About?" (Frederick B. Tuttle, Jr.);…

Tuttle, Frederick B., Jr., Ed.

377

Dune-associated sand fluxes at the nearshore termination of a banner sand bank (Helwick Sands, Bristol Channel)  

NASA Astrophysics Data System (ADS)

Sand dunes typically migrate in opposing directions along the two sides of sand 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 Sands, 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. Sand 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 bed.

Schmitt, Thierry; Mitchell, Neil C.

2014-03-01

378

Gravity flow and solute dispersion in variably saturated sand  

NASA Astrophysics Data System (ADS)

Solute dispersion in porous media depends on the structure of the velocity field at the pore scale. Hence, dispersion is expected to change with water content and with mean flow velocity. We performed laboratory experiments using a column of repacked fine-grained quartz sand (0.1-0.3 mm grain size) with a porous plate at the bottom to controle the water potential at the lower boundary. We established gravity flow conditions - i.e. constant matric potential and water content throughout the column - for a number of different irrigation rates. We measured breakthrough curves during unit gradient flow for an inert tracer which could be described by the convection-dispersion equation. As the soil water content decreased we observed an initially gradual increase in dispersivity followed by an abrupt increase below a threshold water content (0.19) and pressure head (-38 hPa). This phenomena can be explained by the geometry of phase distribution which was simulated based on Xray-CT images of the porous structure.

Kumahor, Samuel K.; de Rooij, Gerrit H.; Vogel, Hans-Joerg

2014-05-01

379

New production techniques for Alberta oil sands  

SciTech Connect

Low world oil prices represent a serious threat to expanded commercial development of the Canadian oil sands in the near term, as they do to all of the higher cost alternatives to crude oil such as oil shales and coal liquefaction. Nonetheless, research and field testing of new technology for production of oil from oil sands are being pursued by industry and government in Alberta. New production technology is being developed in Canada to produce synthetic oil from the vast resources of bitumen trapped in the oil sands and bituminous carbonates of northern Alberta. This technology includes improved methods of mining, extraction, and up-grading of bitumen from near-surface deposits as well as new drilling and production techniques for thermal production of bitumen from the more deeply buried reservoirs. Of particular interest are the cluster drilling methods designed to reduce surface disturbance and the techniques for horizontal drilling of wells from underground tunnels to increase the contact of injection fluids with the reservoir. The history of oil sands technology development, the new drilling technology, and synthetic crude oil conversion are briefly described. 17 references.

Carrigy, M.A.

1986-12-19

380

Alberta ERCB lists active oil sands projects  

SciTech Connect

The Alberta Energy Resources Conservation Board listed all active commercial and experimental oil sands projects as of December, 1986, as shown in the accompanying table. The recovery method and the name of the field and operator of the project are given for both commercial and experimental projects in the Athabasca, Cold Lake, and Peace River deposits.

Not Available

1987-03-01

381

Thermal recovery of hydrocarbon from tar sands  

Microsoft Academic Search

The present invention relates to a method for the recovery of oil from subterranean hydrocarbon-bearing formations containing low API gravity viscous oils or bitumens. More particularly, the invention relates to the production of bitumens and hydrocarbons from reservoirs of low mobility, such as tar sand formations. This can be achieved by the injection of a mixture of an oxygen-containing gas

D. A. Redford; S. M. Creighton

1977-01-01

382

Developing Alberta's oil sands, 1920--2002  

Microsoft Academic Search

This dissertation examines the origins and development of the Alberta oil sands industry over the last century from a scientific project to a commercial endeavor. Based on extensive use of primary sources, the manuscript integrates the developments in a number of fields (politics, international relations, business and economics, and changing oil-recovery technology) that have made it possible to \\

Paul Anthony Chastko

2002-01-01

383

Secondary froth wash. [Oil Sand Processing  

Microsoft Academic Search

A process is described for the removal of bitumen from secondary froth formed during the hot-water processing of Athabasca tar sands. More particularly, the process utilizes the intimate contacting of a hot water wash with a secondary froth and subsequent intimate contacting of the bitumen with the fresh hot water. The amount of solids in a secondary froth is reduced

Kaminsky

1973-01-01

384

Economic Potential of Domestic Tar Sands.  

National Technical Information Service (NTIS)

Analysis of the domestic tar sand resources and the technologies currently available for recovering them indicates that: (1) Much of the resource is lean and scattered, having too little overburden for an in situ thermal process and too much overburden fo...

V. A. Kuuskraa S. Chalton T. M. Doscher

1978-01-01

385

Externally catalyzed epoxy for sand control  

Microsoft Academic Search

A new and improved system for performing sand consolidation using epoxy plastic has been developed. The consolidation method includes preflushing the formation with a permeability enhancing organic chemical (the monobutyl ether of ethylene glycol) and injection of the resin solution which is followed by oil containing the catalyst. The resin solution is the wetting phase, the low-aromatic, nonolefinic catalyst-containing oil

F. A. Brooks; T. W. Muecke; W. P. Rickey; J. K. Kerver

1972-01-01

386

EASTERN TIGHT SANDS, A STIMULATION ASSESSMENT  

Microsoft Academic Search

This study is an evaluation of massive hydraulic fracturing and dendritic fracturing applied to four tight gas sands of the Eastern United States. A total of ten fracturing treatments were performed in the Berea, Benson, Clinton and Medina formations. The objective of this program was to determine whether a meaningful productivity increase could result from the applicationof new fracturing techniques

Steven McKetta; Gregory Koziar; Louis Cook

1980-01-01

387

FERC decontrols tight sands, stripper gas  

Microsoft Academic Search

The Federal Energy Regulatory Commission (FERC) voted 5-0 in mid-November 1984 to include natural gas from stripper and tight sands wells in with other categories of decontrolled gas rather than leave it under controls as expected. Full impact from the rulemaking is hard to assess but, according to Brian Spillane, executive vice president of Barrett Resources Corporation in Denver, large

1984-01-01

388

Porosity and Permeability of Tight Sands  

Microsoft Academic Search

Detailed analyses of more than 50 core samples of western tight sands have resulted in several unanticipated observations that are set forth in this paper. Core analyses performed under stress representative of producing conditions provided data on porosity, pore volume compressibility, stress dependence of permeability to gas, and slope of the Klinkenberg plot (permeability at constant net stress vs. the

P. L. Randolph; D. J. Soeder; Prasan Chowdiah

1984-01-01

389

AMPEROMETRIC TITRATION OF THORIUM IN MONAZITE SANDS  

Microsoft Academic Search

A practical method for the separation and amperometric determination of ; thorium in monazite sands is proposed. The attack is carried out with sulfuric ; acid on 10-gram samples; thorium and the rare earths are separated by a single ; precipitation with oxalic acid, and the final amperometric titration is made with ; ammonium paramolybdate as titrant. The composition of

J. J. Burastero; R. W. Martres

1962-01-01

390

V-2 Rocket at White Sands  

NASA Technical Reports Server (NTRS)

A V-2 rocket takes flight at White Sands, New Mexico, in 1946. The German engineers and scientists who developed the V-2 came to the United States at the end of World War II and continued rocket testing under the direction of the U. S. Army, launching more than sixty V-2s.

1946-01-01

391

A note on tidally generated sand waves  

NASA Astrophysics Data System (ADS)

The process leading to the formation of sand waves in tide dominated coastal areas is investigated by means of the linear stability analysis of a flat sandy bottom subject to oscillatory tidal currents. The conditions for the decay or amplification of small bottom perturbations are determined for arbitrary values of the parameters of the problem. According to field observations, the initial growth of sand waves requires a minimum amplitude of the tidal current, even when the critical bed shear stress for the initial motion of sediment is set equal to zero. Moreover the minimum amplitude depends on sediment characteristics. In particular, the analysis shows that sand waves appear only for a sandy bottom and their growth does not take place when a coarse sediment covers the sea bed. The solution procedure extends the truncation method which is often used to describe the flow generated by the interaction of bottom perturbations with the oscillatory tidal current. The obtained results show that the truncation method describes the mechanism inducing the growth of sand waves, but values of the parameters exist for which its results are not quantitatively accurate. Finally, the asymptotic approach for large values of both r, which is the ratio between the amplitude of the horizontal tidal excursion and the wavelength of the bottom perturbations, and of the stress parameter s is modified in the bottom boundary layer to describe cases characterized by values of s of order one, which is the order of magnitude suggested by an analysis of field data.

Besio, G.; Blondeaux, P.; Frisina, P.

2003-06-01

392

Geology of the Athabasca oil sands  

Microsoft Academic Search

In-place bitumen resources in the Alberta oil sands are estimated at 1350 billion barrels. Open-pit mining and hot water extraction methods, which involve the handling of huge tonnages of earth materials, are being employed in the two commercial plants now operating. In situ recovery methods will be required to tap the 90 percent of reserves that are too deeply buried

G. D. Mossop

1980-01-01

393

Development of the oil sands of Canada  

Microsoft Academic Search

The estimated amount of bitumen in the Alberta oil sands is of the order of 1000 billion barrels; this quantity exceeds the known world reserves of oil by 50 percent. However, a large part of this bitumen is either too deeply buried or too thinly concentrated for possible economic recovery. A thermal hydrocracking process has been developed for application to

J. M. Denis; B. B. Pruden; C. Lafkas

1978-01-01

394

Oil sands: resource, recovery, and industry  

Microsoft Academic Search

An overview of the oil sand industry is presented, including a description of resources and technologies used for producing petroleum substitutes. The focus of the work is on the status and potential of developments in Canada (primarily Alberta) and the US (primarily Alabama, California, Kentucky, New Mexico, Texas, and Utah). Reserves are estimated at 1000 billion bbl in Canada and

C. H. Cox; G. L. Baughman

1980-01-01

395

Geology of the Athabasca oil sands  

Microsoft Academic Search

In-place bitumen resources in the Alberta oil sands are estimated at 1350 billion barrels. Open-pit mining and hot water extraction methods, which involve the handling of huge tonnages of earth materials, are being employed in the two commercial plants now operating. In situ recovery methods will be required to tap the 90% of reserves that are too deeply buried to

G. D. Mossop

1980-01-01

396

Bitumen-Sand Mixes for Road Bases.  

National Technical Information Service (NTIS)

The cost of bitumen-sand mixes can be reduced by using less bitumen than is necessary for surface durability, provided they are surface-dressed to protect them from abrasion. To determine whether a road built using this technique gives adequate performanc...

F. H. P. Williams

1968-01-01

397

EXPRESSING SUPPLY LIMITATION IN SAND SALTATION  

EPA Science Inventory

Saltation-driven sandblasting is the most effective producer of windblown dust. Modeling of wind-blown dust emissions requires an efficient parameterization of sand flux in the saltating mode. According to the theory of P. R. Owen the horizontal mass flux of saltating uniform p...

398

Evaluation of Fractal Dimension of Injected Sand  

Microsoft Academic Search

The aim of this study is to show how fractal analysis can be effectively used to characterize the texture of porous solids. The materials under study were series of injected Loire Sand. Data from MIP tests were analyzed using fractal models. The employed methods were those proposed by Neimark, Friesen and Mikula. These approaches are able to supply a fractal

A. Aït; N. Saiyouri; Y. Hicher

399

Recovery of heavy oil from oil sands  

Microsoft Academic Search

A method is described for the recovery of heavy oil in substantially its original state from a formation of unconsolidated oil sands. A plurality of vertically spaced, interconnected conduits provide an enclosed continuous fluid path through the formation. Heated fluid, from any source, is passed through these conduits for indirectly heating the oil to reduce its viscosity sufficiently that it

Cook

1967-01-01

400

Guide to preparing SAND reports. Revised  

Microsoft Academic Search

This guide contains basic information needed to produce a SAND report. Its guidelines reflect DOE regulation and Sandia policy. The guide includes basic writing instructions in an annotated sample report; guidance for organization, format, and layout of reports produced by line organizations; and information about conference papers, journal articles, and brochures. The appendixes contain sections on Sandia`s preferred usage, equations,

1996-01-01

401

Oil shale, tar sands, and related materials  

Microsoft Academic Search

This sixteen-chapter book focuses on the many problems and the new methodology associated with the commercialization of the oil shale and tar sand industry. Topics discussed include: an overview of the Department of Energy's oil shale R, D, and D program; computer simulation of explosive fracture of oil shale; fracturing of oil shale by treatment with liquid sulfur dioxide; chemistry

Stauffer

1981-01-01

402

MONAZITE SANDS OF BIHAR AND WEST BENGAL  

Microsoft Academic Search

Large monazite pilacers with other associated minerals, e.g., ilmenite, ; rutile, sililimanite, zircon, etc., are known to occur in the western and eastern ; seaboards of India. Lately similar sands have been discovered in inland areas in ; the older alluvium capping the Ranchi Plateau in Binar and in simiilar formations ; in the extensive low lying plains of Koleibera

V. G. Shirke; B. D. Chatterji

1959-01-01

403

2. GENERAL VIEW OF COMPLEX FROM SANDPIT LOOKING NORTHEAST, SAND ...  

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

2. GENERAL VIEW OF COMPLEX FROM SANDPIT LOOKING NORTHEAST, SAND DRAINING & DRYING BUILDING (left) AND SAND-SORTING BUILDING (right) - Mill "C" Complex, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

404

1. GENERAL VIEW OF COMPLEX FROM SANDPIT LOOKING NORTHEAST, SAND ...  

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

1. GENERAL VIEW OF COMPLEX FROM SANDPIT LOOKING NORTHEAST, SAND DRAINING & DRYING BUILDING (left) AND SAND-SORTING BUILDING (right) - Mill "C" Complex, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

405

3. GENERAL VIEW OF COMPLEX LOOKING SOUTH, SAND DRAINING & ...  

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

3. GENERAL VIEW OF COMPLEX LOOKING SOUTH, SAND DRAINING & DRYING BUILDING (right) AND SAND-SORTING BUILDING (left) - Mill "C" Complex, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

406

NASA White Sands Test Facility Remote Hypervelocity Test Laboratory  

NASA Video Gallery

Tour the NASA White Sands Test Facility's Remote Hypervelocity Test Laboratory in Las Cruces, New Mexico. To learn more about White Sands Test Facility, go to http://www.nasa.gov/centers/wstf/home/...

407

Testing and Evaluation of Recovered Traction Sanding Material.  

National Technical Information Service (NTIS)

The Montana Department of Transportation (MDT) is searching for a solution to the accumulation of traction sand that is applied to Montana highways every winter. An analysis of reuse and recycle options for salvaged traction sand was conducted using resul...

A. Foster R. Mokwa

2013-01-01

408

Borehole Mining: An Environmentally Compatible Method for Mining Oil Sands.  

National Technical Information Service (NTIS)

This report presents the results of a demonstration of the technical, economic, and environmental feasibility of hydraulic borehole mining of shallow oil sands. Borehole mining offers a method for extracting the oil sands with minimal disturbance to envir...

G. S. Knoke W. R. Archibald

1980-01-01

409

Tar Sand Process Water Control Technology. Draft Final Report.  

National Technical Information Service (NTIS)

The location, geology, reservoir and oil properties of the major tar sand deposits of the United States are described. Past and present tar sand oil recovery processes are discussed with reference to their state of development, water requirements, waste t...

R. Kahle

1981-01-01

410

1. GENERAL VIEW OF SAND HOUSE, TANK AND CAR SHELTER ...  

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

1. GENERAL VIEW OF SAND HOUSE, TANK AND CAR SHELTER LOOKING NORTHWEST. MINE CARS IN FOREGROUND. - Eureka No. 40, Sand House & Tank, East of State Route 56, North of Little Paint Creek, Scalp Level, Cambria County, PA

411

Filtration of Activated Sludge Secondary Effluents Through Sand and Anthracite-Sand Beds.  

National Technical Information Service (NTIS)

Laboratory filtration studies were conducted on treated sewage effluent from a pilot activated sludge plant operated to provide effluent and mixed liquid solids for use in the experiments. The filtration media used were sand and a combination of anthracit...

Y. Misaka, L. B. Polkowski

1969-01-01

412

Imaging of Acoustic Waves in Sand  

SciTech Connect

There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.

Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall

2003-08-01

413

Tar sand and heavy oil resources and technology  

Microsoft Academic Search

Tar-sand resources in the U.S. are not as concentrated as the Canadian Athabasca deposits, but they are significant; the amount recoverable is estimated to be 25 to 35 billion barrels. Some of the characteristics of tar sands and heavy oil sands and their occurrence are discussed. The single large-scale production of bitumen from tar sands is the operation of Great

1972-01-01

414

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

415

22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL ...  

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

22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL AND TEST LAB FOR UNIT NO. 2 GREY IRON DISAMATIC. SAND CASTING TECHNICIAN, ROY BATES, TESTS THE WEIGHT OF THE SAND, DRYS IT, AND WEIGHT IT AGAINST STANDARDS TO CALCULATE THE CORRECT MOISTURE NEEDED FOR DIFFERENT MOLDS. THE SAND MIX VARY WITH THE SIZE AND COMPOSITION OF THE CASTING. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

416

Fine-grained linings of leveed channels facilitate runout of granular flows  

NASA Astrophysics Data System (ADS)

Catastrophic dense granular flows, such as occur in rock avalanches, debris flows and pyroclastic flows, move as fully shearing mixtures that have approximately 60 vol.% solids and tend to segregate to form coarse-grained fronts and leveed channels. Levees restrict spreading of unconfined flows and form as coarse particles that become concentrated in the top of the flow are transported to the front and then advect to the sides in the flow head. Channels from which most material has drained away down slope are commonly lined with fine-grained deposit, widely thought to remain from the tail of the waning flow. We show how segregation in experimental dense flows of carborundum or sand (300-425 ?m) mixed with spherical fine ballotini (150-250 ?m), on rough slopes of 27-29°, produces fine-grained channel linings that are deposited with the levees, into which they grade laterally. Maximum runout distance is attained with mixtures containing 30-40% sand, just sufficient to segregate and form levees that are adequately robust to restrict the spreading attributable to the low-friction fines. Resin impregnation and serial sectioning of deliberately arrested experimental flows shows how fines-lined levees form from the flow head; the flows create their own stable 'conduit' entirely from the front, which in a geophysical context can play an important mechanistic role in facilitating runout. The flow self-organization ensures that low-friction fines at the base of the segregated channel flow shear over fine-grained substrate in the channel, thus reducing frictional energy losses. We propose that in pyroclastic flows and debris flows, which have considerable mobility attributable to pore-fluid pressures, such fine-grained flow-contact zones form similarly and not only reduce frictional energy losses but also reduce flow-substrate permeability so as to enhance pore-fluid pressure retention. Thus the granular flow self-organization that produces fine-grained channel linings can be an important factor in facilitating long runout of catastrophic geophysical flows on the low slopes (few degrees) of depositional fans and aprons around mountains and volcanoes.

Kokelaar, B. P.; Graham, R. L.; Gray, J. M. N. T.; Vallance, J. W.

2014-01-01

417

Earthquake-induced liquefaction of fine-grained soils - considerations from Japanese research. Final report, October 1986-September 1988  

SciTech Connect

Liquefaction potential of various types of soils has received a great deal of research attention in the geotechnical community over the previous two decades. Dramatic occurrences of liquefaction in saturated deposits of fine, uniformly graded sands in the Japanese city of Niigata and surrounding areas resulting from ground shaking during the 16 June 1964 earthquake spawned extensive studies to develop methodologies for assessing the potential for liquefaction of predominantly clean sands throughout Japan and worldwide. Japanese researchers have recently performed laboratory and field studies to assess the influence of variations in grain-size distribution and soil-index properties of liquefaction potential of fine-grained soils. Several Corps of Engineers dams in seismically active areas are founded on fine-grained, low plasticity alluvial deposits. This report reviews current practices applied to study the phenomenon of fine-grained soil liquefaction, with emphasis on recent Japanese laboratory and in situ testing research. The findings will promote efficiency of effort in the conduct of subsequent laboratory-testing efforts toward the development of specific procedures for use by the Corps and others in assessing the potential for earthquake-induced liquefaction to occur in fine-grained soils.

Koester, J.P.; Tsuchida, T.

1988-12-01

418

Hydrodynamic implications of textural trends in sand deposits of the 2004 tsunami in Sri Lanka  

NASA Astrophysics Data System (ADS)

Field observations and sediment samples at a coastal-plain setting in southeastern Sri Lanka were used to document the erosional and depositional impacts of the 2004 Indian Ocean tsunami and to interpret the hydrodynamic processes that produced an extensive sand-sheet deposit. Tsunami deposit thicknesses ranged from 6 to 22 cm with thickness being controlled partly by antecedent topography. The deposit was composed of coarse to medium sand organized into plane-parallel laminae and a few laminasets. Vertical textural trends showed an overall but non-systematic upward fining and upward thinning of depositional units with an upward increase in heavy-mineral laminations at some locations. Repeated patterns in the vertical textural trends (upward fining, upward coarsening, uniform) were used to subdivide and correlate the deposit into five hydro-textural stratigraphic units. The depositional units were linked to hydrodynamic processes and upcurrent conditions, such as rates of sediment supply and composition of the sediment sources. Vertical changes in grain-size distributions recorded the depositional phases associated with flow acceleration, initial unsteady pulsating flow, relatively stable and uniform flow, flow deceleration, slack water, and return flow or flow redirection. Study results suggest that vertical textural trends from multiple cross-shore sections can be used to interpret complex tsunami flow histories, but at the location examined, interpretation of the lateral textural trends did not provide a basis for identifying the correct sediment transport pathways because flow near the landward boundary was multidirectional.

Morton, Robert A.; Goff, James R.; Nichol, Scott L.

2008-06-01

419

Flowsheet modifications for dissolution of sand, slag, and crucible residues in the F-canyon dissolvers  

SciTech Connect

An initial flowsheet for the dissolution of sand, slag, and crucible (SS{ampersand}C) was developed for the F- Canyon dissolvers as an alternative to dissolution in FB-Line. In that flowsheet, the sand fines were separated from the slag chunks and crucible fragments. Those two SS{ampersand}C streams were packaged separately in mild-steel cans for dissolution in the 6.4D dissolver. Nuclear safety constraints limited the dissolver charge to approximately 350 grams of plutonium in two of the three wells of the dissolver insert and required 0.23M (molar) boron as a soluble neutron poison in the 9.3M nitric acid/0.013M fluoride dissolver solution. During the first dissolution of SS{ampersand}C fines, it became apparent that a significant amount of the plutonium charged to the 6.4D dissolver did not dissolve in the time predicted by previous laboratory experiments. The extended dissolution time was attributed to fluoride complexation by boron. An extensive research and development (R{ampersand}D) program was initiated to investigate the dissolution chemistry and the physical configuration of the dissolver insert to understand what flowsheet modifications were needed to achieve a viable dissolution process.

Rudisill, T.S.; Karraker, D.G.; Graham, F.R.

1997-12-01

420

Hydrodynamic implications of textural trends in sand deposits of the 2004 tsunami in Sri Lanka  

USGS Publications Warehouse

Field observations and sediment samples at a coastal-plain setting in southeastern Sri Lanka were used to document the erosional and depositional impacts of the 2004 Indian Ocean tsunami and to interpret the hydrodynamic processes that produced an extensive sand-sheet deposit. Tsunami deposit thicknesses ranged from 6 to 22??cm with thickness being controlled partly by antecedent topography. The deposit was composed of coarse to medium sand organized into plane-parallel laminae and a few laminasets. Vertical textural trends showed an overall but non-systematic upward fining and upward thinning of depositional units with an upward increase in heavy-mineral laminations at some locations. Repeated patterns in the vertical textural trends (upward fining, upward coarsening, uniform) were used to subdivide and correlate the deposit into five hydro-textural stratigraphic units. The depositional units were linked to hydrodynamic processes and upcurrent conditions, such as rates of sediment supply and composition of the sediment sources. Vertical changes in grain-size distributions recorded the depositional phases associated with flow acceleration, initial unsteady pulsating flow, relatively stable and uniform flow, flow deceleration, slack water, and return flow or flow redirection. Study results suggest that vertical textural trends from multiple cross-shore sections can be used to interpret complex tsunami flow histories, but at the location examined, interpretation of the lateral textural trends did not provide a basis for identifying the correct sediment transport pathways because flow near the landward boundary was multidirectional.

Morton, R. A.; Goff, J. R.; Nichol, S. L.

2008-01-01

421

Fine-Grained Layered Multicast  

Microsoft Academic Search

Traditional approaches to receiver-driven layered multicast have advocated the benefits of cumulative layering, which can enable coarse-grained congestion control that complies with TCP-friendliness equations over large time scales. In this paper, we quantify the costs and benefits of using non-cumulative layering and present a new, scalable multicast congestion control scheme which provides a fine-grained approximation to the behavior of TCP

John W. Byers; Michael Luby; Michael Mitzenmacher

2001-01-01

422

Dense, finely, grained composite materials  

DOEpatents

Dense, finely grained composite materials comprising one or more ceramic phase or phase and one or more metallic and/or intermetallic phase or phases are produced by combustion synthesis. Spherical ceramic grains are homogeneously dispersed within the matrix. Methods are provided, which include the step of applying mechanical pressure during or immediately after ignition, by which the microstructures in the resulting composites can be controllably selected.

Dunmead, Stephen D. (Davis, CA); Holt, Joseph B. (San Jose, CA); Kingman, Donald D. (Danville, CA); Munir, Zuhair A. (Davis, CA)

1990-01-01

423

Investigation of the sand sea with the tallest dunes on Earth: China's Badain Jaran Sand Sea  

NASA Astrophysics Data System (ADS)

China's Badain Jaran Sand Sea features the tallest dunes on Earth and a unique mega-dune-lake landscape. It had been explored little until the 1990s, though early scientific explorations surrounding the sand sea had begun by the early 20th century. Heated debates now focus on the desert environment, and particularly how the mega-dunes and desert lakes develop and evolve. This paper reviews the status of these debates and summarizes the supporting evidences. The environmental research mainly concerns formation and evolution of the sand sea, and its relationship with climate change. The proposed formation time ranges from the Early Pleistocene to the Holocene. Opinions vary about climate change on different time scales. The reconstructed climate change history is shorter than the sand sea's history, with the longest record extending to the Late Pleistocene. The mega-dune research focuses on sediments, dune morphology, and formation processes. It remains unclear whether the mega-dunes result primarily from wind action, control by the underlying topography, or groundwater maintenance. The sources of lake water are also debated, but there are four main hypotheses: atmospheric precipitation, groundwater from nearby areas, precipitation and snowmelt in remote areas such as the Qilian Mountains and the Qinghai-Tibetan Plateau, or paleowater that formed during past periods of wet climate. We believe that the sand sea deserves further study in terms of its dune geomorphology, evolution, and hydrology, and their responses to climate change. Meteorological and hydrological observations and monitoring in the sand sea are particularly necessary.

Dong, Zhibao; Qian, Guangqiang; Lv, Ping; Hu, Guangyin

2013-05-01

424

Experimental investigation of cephapirin adsorption to quartz filter sands and dune sands  

NASA Astrophysics Data System (ADS)

Batch experiments were performed to investigate cephapirin (a widely used veterinary antibiotic) adsorption on various size sands of low total organic carbon content (0.08-0.36 wt%). In the aqueous concentration range investigated (11-112 ?mol/L cephapirin), adsorption to nearly pure quartz filter sands (0.50-3.35 mm diameter) is low. Isotherms are S-shaped and most display a region of minimum adsorption, where decreased adsorption occurs with increasing solution concentration, followed by increased adsorption at higher concentrations. Cephapirin adsorption to quartz-rich, feldspar-bearing dune sands (0.06-0.35 mm diameter), and the smallest quartz filter sand investigated (0.43-0.50 mm), can be described by linear sorption isotherms over the range of concentrations investigated. Distribution coefficients ( K d) range from 0.94 to 3.45 L/kg. No systematic relationship exists between grain size and amount of adsorption for any of the sands investigated. Cephapirin adsorption is positively correlated to the feldspar ratio (K-feldspar/(albite + Ca-plagioclase). Feldspar-ratio normalization of distribution coefficients was more effective than organic carbon normalization at reducing variability of K d values in the dune sands investigated.

Peterson, Jonathan W.; O'Meara, Theresa A.; Seymour, Michael D.

2008-08-01

425

Metabolism of BTEX and naphtha compounds to methane in oil sands tailings.  

PubMed

Naphtha, comprising low molecular weight aliphatics and aromatics (C3-C14), is used as a diluent in processing of bitumen from oil sands. A small fraction (<1%) is lost to tailings waste and incorporated into mature fine tailings (MFT). BTEX (benzene, toluene, ethylbenzene, and xylenes) and whole naphtha were assessed for biodegradation under methanogenic conditions using MFT from an oil sands tailings settling basin. MFT spiked with 0.05-0.1% w/v of BTEX compounds produced up to 2.1 (+/-0.1) mmol of methane during 36 weeks of incubation. Metabolism of 0.5-1.0% w/v naphtha in MFT yielded up to 5.7 (+/-0.2) mmol of methane during 46 weeks of incubation. Gas chromatographic analyses showed that BTEX degraded in the sequence: toluene > o-xylene > m- plus p-xylene > ethylbenzene > benzene. Only 15-23% of whole naphtha, mainly n-alkanes (in the sequence: nonane > octane > heptane) and some BTEX compounds (toluene > o-xylene > m-xylene), was metabolized. Other naphtha constituents, such as iso-paraffins and naphthenes, remained unchanged during this period. These results suggest that the microbial communities in the MFT can readily utilize certain fractions of unrecovered naphtha in oil sands tailings and support methanogenesis in settling basins. Current study findings could influence extraction process, MFT management, and reclamation options. PMID:17438786

Siddique, Tariq; Fedorak, Phillip M; MacKinnon, Michael D; Foght, Julia M

2007-04-01

426

Longitudinal variability in hydraulic geometry and substrate characteristics of a Great Plains sand-bed river  

NASA Astrophysics Data System (ADS)

Downstream trends in hydraulic geometry and substrate characteristics were investigated along a 200 km reach of the Ninnescah River in south central Kansas, USA. The Ninnescah River is a large sand-bed, perennial, braided river located in the Central Plains physiographic province and is a tributary of the Arkansas River. Hydraulic geometry characteristics were measured at eleven reaches and included slope, sinuosity, bankfull channel width, and bankfull channel depth. Results indicated that the Ninnescah River followed a predicted trend of decreasing slope and increasing depth and width downstream. There were localized divergences in the central tendency, most notability downstream of a substantial tributary that is impounded and at the end of the surveying reach where the Ninnescah River approaches the Arkansas River. Surface grain-size samples were taken from the top 10 cm of the bed at five points across the wetted cross-section within each of the 11 reaches. Sediment analyses demonstrated a significant trend in downstream fining of surface grain-sizes (D90 and D50) but unlike previous studies of sand-bedded rivers we observed coarsening of substrates downstream of the major tributary confluence. We propose that the overall low discharge from the tributary was the primary reason for coarsening of the bed downstream of the tributary. Results of this study provide valuable baseline information that can provide insight in to how Great Plains sand-bed systems may be conserved, managed, and restored in the future.

Costigan, Katie H.; Daniels, Melinda D.; Perkin, Joshuah S.; Gido, Keith B.

2014-04-01

427

Calculation of Microwave Attenuation Effect Due to Charged Sand Particles  

Microsoft Academic Search

Based on the forward scattering amplitude function for charged sand particles under the Rayleigh approximation and the effective permittivity method, a calculation model for microwave attenuation due to charged sand particles is given in terms of equal sized distribution and lognormal size distribution, and the attenuation is calculated and analyzed. The results show that the attenuation with charged sand is

Q. F. Dong; J. D. Xu; Y. L. Li; H. Zhang; M. J. Wang

2010-01-01

428

Calculation of Microwave Attenuation Effect Due to Charged Sand Particles  

Microsoft Academic Search

Based on the forward scattering amplitude function for charged sand particles under the Rayleigh approximation and the effective permittivity method, a calculation model for microwave attenuation due to charged sand particles is given in terms of equal sized distribution and lognormal size distribution, and the attenuation is calculated and analyzed. The results show that the attenuation with charged sand is

Q. F. Dong; J. D. Xu; Y. L. Li; H. Zhang; M. J. Wang

2011-01-01

429

Tar sands: a new fuels industry takes shape. [Alberta  

Microsoft Academic Search

Problems have delayed exploitation of tar sands in Alberta, but they have certainly not halted it. One by one, these problems have been overcome until, today, tar sands are the most promising near term alternative source of fossil fuels. One company has been mining tar sands and extracting oil from them for 10 yr, the last 2 yr at a

Maugh; T. H. II

1978-01-01

430

Well completion process for formations with unconsolidated sands  

DOEpatents

A method for consolidating sand around a well, involving injecting hot water or steam through well casing perforations in to create a cement-like area around the perforation of sufficient rigidity to prevent sand from flowing into and obstructing the well. The cement area has several wormholes that provide fluid passageways between the well and the formation, while still inhibiting sand inflow.

Davies, David K. (Kingwood, TX); Mondragon, III, Julius J. (Redondo Beach, CA); Hara, Philip Scott (Monterey Park, CA)

2003-04-29

431

Policy Analysis of the Canadian Oil Sands Experience, Topical Report.  

National Technical Information Service (NTIS)

For those who support U.S. oil sands development, the Canadian oil sands industry is often identified as a model the U.S. might emulate, yielding financial and energy security benefits. For opponents of domestic oil sands development, the Canadian oil san...

K. Uchitel R. Keiter

2013-01-01

432

Numerical simulation of wind sand movement in straw checkerboard barriers.  

PubMed

Straw checkerboard barrier (SCB) is the most representative antidesertification measure and plays a significant role in antidesertification projects. Large-eddy simulation and discrete-particle tracing were used to numerically simulate the wind sand movement inside the straw checkerboard barrier (SCB), study the movement characteristics of sand particles, find the transverse velocities of sand particles and flow field, and obtain the contour of the transverse velocity of coupled wind field within the SCB. The results showed that 1) compared with that at the inlet of the SCB, the sand transport rate inside the SCB greatly decreases and the speed of sand grain movement also evidently drops, indicating that the SCB has very good sand movement preventing and fixing function; 2) within the SCB there exists a series of unevenly distributed eddies of wind sand flow, their strength decreases gradually with increasing the transverse distance; 3) affected by eddies or reflux, sand particles carried by the wind sand flow have to drop forward and backward the two interior walls inside the SCB, respectively, forming a v-shaped sand trough; 4) the sand transport rate gradually decreases with increasing number of SCBs, which reveals that the capacity of the wind field to transport sand particles decreases. This research is of significance in sandstorm and land desertification control. PMID:24026396

Huang, Ning; Xia, Xianpan; Tong, Ding

2013-09-01

433

Microwave applications to oil sands and petroleum: A review  

Microsoft Academic Search

This review provides a general overview of microwave applications in oil sands bitumen or shale oil production in petroleum upgrading. The vast oil reserves in the oil sands of Alberta will become a major source of petroleum products in the near future and a number of alternative technologies have been explored for the production and upgrading of oil sands and

Sateesh Mutyala; Craig Fairbridge; J. R. Jocelyn Paré; Jacqueline M. R. Bélanger; Siauw Ng; Randall Hawkins

2010-01-01

434

Understanding the Canadian oil sands industry's greenhouse gas emissions  

Microsoft Academic Search

The magnitude of Canada's oil sands reserves, their rapidly expanding and energy intensive production, combined with existing and upcoming greenhouse gas (GHG) emissions regulations motivate an evaluation of oil sands-derived fuel production from a life cycle perspective. Thirteen studies of GHG emissions associated with oil sands operations are reviewed. The production of synthetic crude oil (SCO) through surface mining and

Alex D. Charpentier; Joule A. Bergerson; Heather L. MacLean

2009-01-01

435

An overview of Canadian oil sand mega projects  

Microsoft Academic Search

There are currently a number of existing oil sand Mega-Projects as well as many other related projects planned and under construction in the Alberta oil sands region. There are many challenges facing the oil sands. The demanding climate conditions cost of extraction, environmental, energy constraints as well as the rising construction costs are examples. To develop this huge petroleum reserve,

R. Paes; M. Throckmorton

2008-01-01

436

Trace elements in Nigerian oil sands and extracted bitumens  

Microsoft Academic Search

The Nigerian oil sands are very extensive with an estimated in place reserves of bitumen\\/heavy oil of over 30 billion barrels. Instrumental Neutron Activation Analysis (INAA) has been used to determine the trace and minor elements in the raw oil sands and bitumens. About 43 trace elements in the raw oil sands and 30 in bitumen extracts were determined. The

A. F. Oluwole; A. H. M. A. Hannan; L. O. Kehinde; A. B. Borishade; O. S. Adegoke

1987-01-01

437

BMM SEPARATION SCREEN PERMITS SAND TO PASS TO BELT CONVEYORS ...  

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

BMM SEPARATION SCREEN PERMITS SAND TO PASS TO BELT CONVEYORS BELOW THAT TRANSPORT THE SAND BACK TO STORAGE AND RECONDITIONING BINS WHILE CASTINGS ARE TRANSPORTED ON ADDITIONAL VIBRATING CONVEYORS TO DEGATING AREAS. - Southern Ductile Casting Company, Shaking, Degating & Sand Systems, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

438

Sand Creek Massacre Project. Volume 1. Site Location Study.  

National Technical Information Service (NTIS)

In May 1999, the Sand Creek Massacre Project Team completed its successful search for the site of the Sand Creek Massacre. On the banks of Sand Creek in Kiowa County, Colorado, an archeological team that included tribal members, National Park Service staf...

2000-01-01

439

The origin, classification and modelling of sand banks and ridges  

Microsoft Academic Search

Sand banks and elongated sand ridges occur in many coastal and shelf seas where there is abundant sand and where the currents are strong enough to move sediment, but they have a wide variety of forms. Their generation requires a source of mobile sediment, either from the local sea bed, or from coast erosion. Most appear to have been created

Keith R Dyer; David A Huntley

1999-01-01

440

Flotation behavior of digested asphalt ridge tar sands  

Microsoft Academic Search

The hot water process for Utah tar sands differs from that used for Canadian tar sands due to inherent differences in respective bitumen viscosities and the nature of bitumen-sand association. Although contact angle measurements of solvent extracted Asphalt Ridge bitumen indicated moderate hydrophobicity, air bubble attachment to the bitumen concentrate is not possible. This suggests that flotation separation is dependent

R. J. Smith; J. D. Miller

1981-01-01

441

Advances in Fine Particle Control Technology.  

National Technical Information Service (NTIS)

The paper discusses advances in fine particle control technology. Currently, the technologies of choice for controlling fine particle emissions from large combustion sources are fabric filters and electrostatic precipitators (ESPs). As these two technolog...

W. Marchant G. Nichols N. Plaks C. B. Sedman

1996-01-01

442

The Optimal Use of Fines and Imprisonment  

Microsoft Academic Search

This paper examines the use of fines and imprisonment to deter individuals from engaging in harmful activities. These sanctions are analyzed separately as well as together, first for identical risk-neutral individuals and then for two groups of risk-neutral individuals who differ by wealth. When fines are used alone and individuals are identical, the optimal fine and probability of apprehension are

A. Mitchell Polinsky; Steven Shavell

1982-01-01

443

36 CFR 910.35 - Fine arts.  

Code of Federal Regulations, 2013 CFR

...Property 3 2013-07-01 2012-07-01 true Fine arts. 910.35 Section 910.35 Parks, Forests, and...Applicable to the Development Area § 910.35 Fine arts. Fine arts, including sculpture, paintings, decorative...

2013-07-01

444

Sand Bank Weakly Nonlinear Stability Analysis  

NASA Astrophysics Data System (ADS)

In the continental shelf, tidal currents often give rise to large scale periodic bed forms named sand banks. Sand banks are long ridges (length of the order of several tens of kilometers) with a spacing (crest to crest distance) up to 10 km and a height up to several tens of meters. Their crests are almost aligned with the tidal currents, forming small positive or negative angles. Although reliable models based on linear stability analyses exist to predict the main geometrical characteristics of the sand banks as they start to appear, little is known on the morphodynamic processes th