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Sample records for gravel sand units

  1. Sand and Gravel Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

  2. Sand and Gravel Deposits

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset is a statewide polygon coverage of sand, gravel, and stone resources. This database includes the best data available from the VT Agency of Natural...

  3. Instream sand and gravel mining: Environmental issues and regulatory process in the United States

    Science.gov (United States)

    Meador, M.R.; Layher, A.O.

    1998-01-01

    Sand and gravel are widely used throughout the U.S. construction industry, but their extraction can significantly affect the physical, chemical, and biological characteristics of mined streams. Fisheries biologists often find themselves involved in the complex environmental and regulatory issues related to instream sand and gravel mining. This paper provides an overview of information presented in a symposium held at the 1997 midyear meeting of the Southern Division of the American Fisheries Society in San Antonio, Texas, to discuss environmental issues and regulatory procedures related to instream mining. Conclusions from the symposium suggest that complex physicochemical and biotic responses to disturbance such as channel incision and alteration of riparian vegetation ultimately determine the effects of instream mining. An understanding of geomorphic processes can provide insight into the effects of mining operations on stream function, and multidisciplinary empirical studies are needed to determine the relative effects of mining versus other natural and human-induced stream alterations. Mining regulations often result in a confusing regulatory process complicated, for example, by the role of the U.S. Army Corps of Engineers, which has undergone numerous changes and remains unclear. Dialogue among scientists, miners, and regulators can provide an important first step toward developing a plan that integrates biology and politics to protect aquatic resources.

  4. Application of surface-geophysical methods to investigations of sand and gravel aquifers in the glaciated Northeastern United States

    Science.gov (United States)

    Haeni, F.P.

    1995-01-01

    Combined use of seismic-refraction, direct-current resistivity, very-low-frequency terrain-resistivity, and inductive terrain-conductivity methods were demonstrated at sites in Connecticut, New York, and Maine. Although no single method can define both the hydrogeologic boundaries and general grain-size characteristics of sand and gravel aquifers, a combination of these methods can. Comparisons of measured electrical properties of aquifers with logs of test holes and wells indicate that, for a given conductivity of ground water, the bulk electrical resistivity of aquifers in the glaciated Northeast increases with grain size.

  5. Controls on the abruptness of gravel-sand transitions

    Science.gov (United States)

    Venditti, J. G.; Church, M. A.; Lamb, M. P.; Domarad, N.; Rennie, C. D.

    2014-12-01

    As gravel-bedded rivers fine downstream, they characteristically exhibit an abrupt transition from gravel- to sand-bed. This is the only abrupt transition in grain-size that occurs in the fluvial system and has attracted considerable attention. A number of competing theories have been proposed to account for the abruptness of the transition, including base-level control, attrition of ~10mm gravel to produce sand, and sediment sorting processes. The prevailing theory for the emergence of abrupt transitions is size selective sorting of bimodal sediment wherein gravel deposits due to downstream declining shear stress, fining the bedload until a sand-bed emerges. We explored this hypothesis by examining grain-size, shear stress, gravel mobility and sand suspension thresholds through the gravel-sand transition (GST) of the Fraser River, British Columbia. The Fraser GST is an arrested gravel wedge with patches of gravel downstream of the wedge forming a diffuse extension. There is an abrupt change in bed slope through the transition that leads to an abrupt change in shear stress. The GST, bed-slope change and backwater caused by the ocean are all coincident spatially, which enhances the sharpness of the GST. Interestingly, the bimodal reach of the river occurs downstream of the GST and exhibits no downstream gradients in shear stress, suspended sediment flux, gravel mobility or sand suspension thresholds. This calls into question the prevailing theory for the emergence of an abrupt GST by size selective sorting. We provide evidence, both empirical and theoretical, that suggests the emergence of an abrupt GST is caused by rapid deposition of sand when fine gravel deposits. We argue that the emergence of gravel-sand transitions is a consequence of gravel-bedded rivers adopting a steeper slope than sand-bedded rivers. The abruptness arises because the bed slope required to convey the gravel load fixes the distal location of a terminal gravel wedge, and once the river has

  6. Noise Exposure and Hearing Loss Among Sand and Gravel Miners

    OpenAIRE

    Landen, Deborah; Wilkins, Steve; Stephenson, Mark; McWilliams, Linda

    2004-01-01

    The objectives of this study were to describe workplace noise exposures, risk factors for hearing loss, and hearing levels among sand and gravel miners, and to determine whether full shift noise exposures resulted in changes in hearing thresholds from baseline values. Sand and gravel miners (n = 317) were interviewed regarding medical history, leisure-time and occupational noise exposure, other occupational exposures, and use of hearing protection. Audiometric tests were performed both before...

  7. Gravel Mobility in a High Sand Content Riverbed

    Science.gov (United States)

    Haschenburger, J. K.

    2017-12-01

    In sand-gravel channels, sand may modify gravel transport by changing conditions of entrainment and promoting longer displacements or gravel may inhibit sand transport if concentrated into distinct deposits, which restrict sand supply with consequences for migrating bedform size or form. This study reports on gravel mobility in the lower San Antonio River, Texas, where gravel content in the bed material ranges from about 1% to more than 20%. Sediment transport observations were collected at three U.S. Geological Survey gauging stations by deploying a Helley-Smith sampler with a 0.2 mm mesh bag from which transport rates and mobile grain sizes were determined. The flow rates sampled translate into an annual exceedance expectation from 0.2% to 98%. Gravel transport rates are generally two orders of magnitude smaller than the rates of sand transport. However, the finest gravels are transported at rates on the same order of magnitude as the coarsest sands. At all sites, the 2 and 2.8 mm fractions are transported at the lowest flow rate sampled, suggesting mobility for at least 38% to as much as 98% of the year. Fractions as large as 8 mm are mobilized at flow rates that are expected between 25% and 53% of the year. The largest fractions captured in the sampling (16 to 32 mm) require flows closer to bankfull conditions that occur no more than 0.8% of the year. Results document that some gravel sizes can be frequently transported in low gradient riverbeds with high sand content.

  8. The gravel sand transition in a disturbed catchment

    Science.gov (United States)

    Knighton, A. David

    1999-03-01

    More than 40 million cubic metres of mining waste were supplied to the Ringarooma River between 1875 and 1984, leading to successive phases of aggradation and degradation. The natural bed material is gravel but, given the volume of introduced load and the fact that much of the input was less than 5 mm in diameter, the size composition of the bed changed from gravel to sand during the phase of downstream progressive aggradation. A very sharp gravel-sand transition developed in which median grain size decreased from over 30 mm to under 3 mm in less than 500 m. With upstream supplies of mining debris becoming depleted first, degradation followed the same downstream progressive pattern as aggradation, causing the transition to migrate downstream. By 1984, the river could be regarded as a series of zones, each characterized by a particular bed condition: a natural cobble-gravel bed, unaffected by mining inputs (0-32 km); pre-disturbance bed re-exposed by degradation over 35-40 years (32-53 km); sandy substrate with a gravel armour produced by differential transport during degradation (53-65 km); sand dominated but with developing surface patches of coarser material (65-75 km); sandy bed reflecting the size composition of the original mining input (75-118 km). Although the gravel-sand transition itself is sharp, the transitional zone is lengthy (53-75 km). As degradation continues, the gravel-sand transition is expected to progress downstream but it has remained in a stable position for 12 years. Indeed, two major floods during the period released large quantities of sand from the sub-armour layer and newly-formed banks of mine tailings, causing fining both above and below the transition. Surface grain size is an adjustable component in the transitional zone as the river strives to recover from a major anthropogenic disturbance.

  9. Injury experience in sand and gravel mining, 1991

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    This Mine Safety and Health Administration (MSHA) informational report reviews in detail the occupational injury and illness experience of sand and gravel mining in the United States for 1991. Data reported by operators of mining establishments concerning work injuries are summarized by work location, accident classification, part of body injured, nature of injury, and occupation. Related information on employment, worktime, and operating activity also is presented. Data reported by independent contractors performing certain work at mining locations are depicted separately in this report. For ease of comparison with other metal and nonmetallic mineral mining industries and with coal mining, summary reference tabulations are included at the end of both the operator and the contractor sections of this report.

  10. Radon diffusion studies in air, gravel, sand, soil and water

    International Nuclear Information System (INIS)

    Singh, B.; Singh, S.; Virk, H.S.

    1993-01-01

    Radon isotopes are practically inert and have properties of gases under conditions of geological interest. During their brief lives their atoms are capable of moving from sites of their generation. Radon diffusion studies were carried out in air, gravel, sand, soil and water using silicon diffused junction electronic detector, Alphameter-400. Diffusion constant and diffusion length is calculated for all these materials. (author)

  11. Experimental investigation on heat transport in gravel-sand materials

    DEFF Research Database (Denmark)

    Maureschat, Gerald; Heller, Alfred

    1997-01-01

    in sand-gravel material, the storage media is to be water satured. In this case, handling of such material on site is rather complex. The conduction is highly dependent on the thermal properties of the storage media and so is the overall thermal performance of a storage applying such media. For sandy...... out in a small size experiment. The experiment consists of a highly insulated box filled with two kinds of sand material crossed by a plastic heat pipe. Heat transfer is measured under dry and water satured conditions in a cross-section.The conclusions are clear. To obtain necessary heat conduction...

  12. Fisher Sand & Gravel New Mexico, Inc. General Air Quality Permit: Related Documents

    Science.gov (United States)

    Documents related to the Fisher Sand & Gravel – New Mexico, Inc., Grey Mesa Gravel Pit General Air Quality Permit for New or Modified Minor Source Stone Quarrying, Crushing, and Screening Facilities in Indian Country.

  13. Sand and gravel mine operations and reclamation planning using microcomputers

    Energy Technology Data Exchange (ETDEWEB)

    Ariffin, J.B.

    1990-02-01

    The purpose of this study is to focus on the application of microcomputers, also known as personal computers, in planning for sand and gravel mine operations and reclamation at a site in Story County, Iowa. This site, called the Arrasmith Pit, is operated by Martin Marietta Aggregates, Inc. The Arrasmith site, which encompasses an area of about 25 acres, is a relatively small site for aggregate mining. However, planning for the concurrent mine operation and reclamation program at this site is just as critical as with larger sites and the planning process is the same.

  14. Sand and gravel mining: effects on ground water resources in Hancock county, Maine, USA

    Science.gov (United States)

    Peckenham, John M.; Thornton, Teresa; Whalen, Bill

    2009-01-01

    Based on this preliminary study, existing sand and gravel mining regulations (in Maine, USA) can be inferred to provide some protection to water resources. Sand and gravel deposits are important natural resources that have dual uses: mining for construction material and pumping for drinking water. How the mining of sand and gravel affects aquifers and change aquifer vulnerability to contamination is not well documented. Mining regulations vary greatly by state and local jurisdiction. This study test metrics to measure the effectiveness of mining regulations. The sand and gravel aquifer system studied is covered with former and active gravel pits to nearly 25% of its areal extent. Data from homeowner interviews and field measurements found scant evidence of changes in water quantity. Water quality analyses collected from springs, streams, ponds and wells indicate that the aquifer was vulnerable to contamination by chloride and nitrate. However, water quality changes can not be related directly to mining activities.

  15. Economic Valuation of Sand and Gravel in Davao del Norte, Philippines

    OpenAIRE

    Tamayo, Adrian; Tagalo, Romulo

    2016-01-01

    The study aims to quantify the economic value of the sand and gravel which is deemed as a non-renewable resource. A survey was conducted to extract the consumer surplus of the households, also construct the demand equation for the resource. With the demand equation for sand and gravel at , the consumer surplus was estimated at P8271. Using the economic valuation technique, the economic value of sand and gravel was estimated at P729,568,368. Thus, a very high value imputed on the environmenta...

  16. SEISMIC VELOCITY DETERMINATION IN GRAVEL AND SANDS USING PIEZOCRYSTALS

    Directory of Open Access Journals (Sweden)

    Santamarina Juan Carlos

    2008-06-01

    Full Text Available The exact determination of seismic waves' propagation velocities has great importance in the geotechnics due to from that it is possible to determine, among other parameters, the dynamic ones: Elasticity E, Rigidity G, Poisson !, compressibility B; as well as to reach a knowledge on the stress-strain behavior for the studied soil samples. The seismic waves transmission considered in tests at laboratory scale carried out in the present work is a phenomenon that produces very small deformation, and so doesn't disturb the material. This allows
    to apply the results in a more general scale to study the behavior of soils in situ and to predict their answer to stress.
    With the purpose to study the response of particulate material subjected to seismic excitements at small scale, samples of gravels and sands were successively introduced in an odometric cell, exciting them with impulsive signals and registering the corresponding seismograms through general purpose piezoelectric transducers embedded in ends of the cell.
    The distance source-receiver was interval increased, which enabled, from the corresponding regression straight lines, to calculate in precise form the propagation velocities (for P waves.
    The tests were carried out in samples of dry alluvial soil with three different grain sizes. The respective frequency spectra of the signals were determined for two packing modes: loose and compact, what added information on the medium characteristics.

  17. Image analysis to measure sorting and stratification applied to sand-gravel experiments

    OpenAIRE

    Orrú, C.

    2016-01-01

    The main objective of this project is to develop new measuring techniques for providing detailed data on sediment sorting suitable for sand-gravel laboratory experiments. Such data will be of aid in obtaining new insights on sorting mechanisms and improving prediction capabilities of morphodynamic models. Two measuring techniques have been developed. The first technique is aimed at measuring the size stratification of a sand-gravel deposit through combining image analysis and a sediment remov...

  18. Land Use and River Degradation Impact of Sand and Gravel Mining

    Science.gov (United States)

    Syah, Putra Rizal Ichsan; Hartuti, Purnaweni

    2018-02-01

    Sand and gravel mining is aimed at providing materials for infrastructure development, as well as providing economical source to the miners. However, the impacts of sand and gravel mining could also cause disturbances to ecological balance, since it is closely related to land use change and river degradation, besides causing conflicts in the miners, the government, and the private relationship. Therefore the government regulation and proper supervision are needed to preserve the ecological balance and decreasing the negative impacts of this mining, and therefore guarantee sustainable development.

  19. 32 CFR 644.551 - Equal opportunity-sales of timber, embedded sand, gravel, stone, and surplus structures.

    Science.gov (United States)

    2010-07-01

    ... § 644.551 Equal opportunity—sales of timber, embedded sand, gravel, stone, and surplus structures... 32 National Defense 4 2010-07-01 2010-07-01 true Equal opportunity-sales of timber, embedded sand, gravel, stone, and surplus structures. 644.551 Section 644.551 National Defense Department of Defense...

  20. Image analysis to measure sorting and stratification applied to sand-gravel experiments

    NARCIS (Netherlands)

    Orrú, C.

    2016-01-01

    The main objective of this project is to develop new measuring techniques for providing detailed data on sediment sorting suitable for sand-gravel laboratory experiments. Such data will be of aid in obtaining new insights on sorting mechanisms and improving prediction capabilities of morphodynamic

  1. Recovering byproduct heavy minerals from sand and gravel, placer gold, and industrial mineral operations

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, J.M.; Martinez, G.M.; Wong, M.M.

    1979-01-01

    The Bureau of Mines, as part of an effort to maximize minerals and metals recovery from domestic resources, has investigated the feasibility of recovering heavy minerals as byproducts from sand and gravel, placer gold, and industrial mineral operations in northern California. Sand samples from about 50 locations were treated by gravity separation to yield heavy-mineral cocentrates (black sands). Mineral compositions of the concentrates were determined by chemical analysis and mineralogical examination. Individual zircon, ilmenite, magnetite, platinum-group metals, thoria, and silica products were prepared from heavy-mineral concentrates by selective separation using low- and high-intensity magnetic, high-tension, and flotation equipment.

  2. Estimated sand and gravel resources of the South Merrimack, Hillsborough County, New Hampshire, 7.5-minute quadrangle

    Science.gov (United States)

    Sutphin, D.M.; Drew, L.J.; Fowler, B.K.

    2006-01-01

    A computer methodology is presented that allows natural aggregate producers, local governmental, and nongovernmental planners to define specific locations that may have sand and gravel deposits meeting user-specified minimum size, thickness, and geographic and geologic criteria, in areas where the surficial geology has been mapped. As an example, the surficial geologic map of the South Merrimack quadrangle was digitized and several digital geographic information system databases were downloaded from the internet and used to estimate the sand and gravel resources in the quadrangle. More than 41 percent of the South Merrimack quadrangle has been mapped as having sand and (or) gravel deposited by glacial meltwaters. These glaciofluvial areas are estimated to contain a total of 10 million m3 of material mapped as gravel, 60 million m3 of material mapped as mixed sand and gravel, and another 50 million m3 of material mapped as sand with minor silt. The mean thickness of these areas is about 1.95 meters. Twenty tracts were selected, each having individual areas of more than about 14 acres4 (5.67 hectares) of stratified glacial-meltwater sand and gravel deposits, at least 10-feet (3.0 m) of material above the watertable, and not sterilized by the proximity of buildings, roads, streams and other bodies of water, or railroads. The 20 tracts are estimated to contain between about 4 and 10 million short tons (st) of gravel and 20 and 30 million st of sand. The five most gravel-rich tracts contain about 71 to 82 percent of the gravel resources in all 20 tracts and about 54-56 percent of the sand. Using this methodology, and the above criteria, a group of four tracts, divided by narrow areas sterilized by a small stream and secondary roads, may have the highest potential in the quadrangle for sand and gravel resources. ?? Springer Science+Business Media, LLC 2006.

  3. A Visual Basic program to classify sediments based on gravel-sand-silt-clay ratios

    Science.gov (United States)

    Poppe, L.J.; Eliason, A.H.; Hastings, M.E.

    2003-01-01

    Nomenclature describing size distributions is important to geologists because grain size is the most basic attribute of sediments. Traditionally, geologists have divided sediments into four size fractions that include gravel, sand, silt, and clay, and classified these sediments based on ratios of the various proportions of the fractions. Definitions of these fractions have long been standardized to the grade scale described by Wentworth (1922), and two main classification schemes have been adopted to describe the approximate relationship between the size fractions.Specifically, according to the Wentworth grade scale gravel-sized particles have a nominal diameter of ⩾2.0 mm; sand-sized particles have nominal diameters from <2.0 mm to ⩾62.5 μm; silt-sized particles have nominal diameters from <62.5 to ⩾4.0 μm; and clay is <4.0 μm. As for sediment classification, most sedimentologists use one of the systems described either by Shepard (1954) or Folk (1954, 1974). The original scheme devised by Shepard (1954) utilized a single ternary diagram with sand, silt, and clay in the corners to graphically show the relative proportions among these three grades within a sample. This scheme, however, does not allow for sediments with significant amounts of gravel. Therefore, Shepard's classification scheme (Fig. 1) was subsequently modified by the addition of a second ternary diagram to account for the gravel fraction (Schlee, 1973). The system devised by Folk (1954, 1974) is also based on two triangular diagrams (Fig. 2), but it has 23 major categories, and uses the term mud (defined as silt plus clay). The patterns within the triangles of both systems differ, as does the emphasis placed on gravel. For example, in the system described by Shepard, gravelly sediments have more than 10% gravel; in Folk's system, slightly gravelly sediments have as little as 0.01% gravel. Folk's classification scheme stresses gravel because its concentration is a function of

  4. Gravel-Sand-Clay Mixture Model for Predictions of Permeability and Velocity of Unconsolidated Sediments

    Science.gov (United States)

    Konishi, C.

    2014-12-01

    Gravel-sand-clay mixture model is proposed particularly for unconsolidated sediments to predict permeability and velocity from volume fractions of the three components (i.e. gravel, sand, and clay). A well-known sand-clay mixture model or bimodal mixture model treats clay contents as volume fraction of the small particle and the rest of the volume is considered as that of the large particle. This simple approach has been commonly accepted and has validated by many studies before. However, a collection of laboratory measurements of permeability and grain size distribution for unconsolidated samples show an impact of presence of another large particle; i.e. only a few percent of gravel particles increases the permeability of the sample significantly. This observation cannot be explained by the bimodal mixture model and it suggests the necessity of considering the gravel-sand-clay mixture model. In the proposed model, I consider the three volume fractions of each component instead of using only the clay contents. Sand becomes either larger or smaller particles in the three component mixture model, whereas it is always the large particle in the bimodal mixture model. The total porosity of the two cases, one is the case that the sand is smaller particle and the other is the case that the sand is larger particle, can be modeled independently from sand volume fraction by the same fashion in the bimodal model. However, the two cases can co-exist in one sample; thus, the total porosity of the mixed sample is calculated by weighted average of the two cases by the volume fractions of gravel and clay. The effective porosity is distinguished from the total porosity assuming that the porosity associated with clay is zero effective porosity. In addition, effective grain size can be computed from the volume fractions and representative grain sizes for each component. Using the effective porosity and the effective grain size, the permeability is predicted by Kozeny-Carman equation

  5. Indoor radon in houses built on gravel and sand deposits in southern Finland

    Directory of Open Access Journals (Sweden)

    Hutri, K.-L.

    1993-06-01

    Full Text Available Studies by the Finnish Centre for Radiation and Nuclear Safety (STUK have shown that, in Finland, indoor radon concentrations are almost twice as high in houses built on sand or gravel as in houses built on other soil types. The aim of this study was to assess the radon risk on eskers, ice-marginal formations, and other gravel and sand deposits on the basis of factors that can be determined from geological maps. Altogether, 514 houses built on gravel and sand deposits were selected for the study from the indoor radon database of STUK. Several geological parameters were determined. Empirical statistical models were used to assess the significance of factors affecting indoor radon in glaciofluvial deposits and the sand-dominant littoral deposits occurring in association with them. A relationship was found between increased indoor radon concentrations and the location of a house on a steep-sided esker, in the southeastern rapakivi granite area and on the upper slope or top of an esker. The steepness of the slope also increased the radon concentration in houses on steep-sided eskers. The effect of the topographic features is due to subterranean air-flows. As estimated from the very sparse till sampling, the elevated uranium concentration increased the indoor radon concentration only in houses built on littoral deposits around eskers and ice-marginal formations.

  6. Compositional Signatures in Acoustic Backscatter Over Vegetated and Unvegetated Mixed Sand-Gravel Riverbeds

    Science.gov (United States)

    Buscombe, D.; Grams, P. E.; Kaplinski, M. A.

    2017-10-01

    Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high-frequency, decimeter-resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand-gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small-scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two-stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain-scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam-to-beam) bed-sonar geometry, are removed. Then, coherent scales between high-resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high-pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low-frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

  7. Compositional signatures in acoustic backscatter over vegetated and unvegetated mixed sand-gravel riverbeds

    Science.gov (United States)

    Buscombe, Daniel; Grams, Paul E.; Kaplinski, Matt A.

    2017-01-01

    Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high-frequency, decimeter-resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand-gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small-scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two-stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain-scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam-to-beam) bed-sonar geometry, are removed. Then, coherent scales between high-resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high-pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low-frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

  8. Suppressing immature house and stable flies in outdoor calf hutches with sand, gravel, and sawdust bedding.

    Science.gov (United States)

    Schmidtmann, E T

    1991-11-01

    Sand, gravel, sawdust, and pine shavings were used as bedding in outdoor calf hutches and compared with straw relative to the density of immature (maggot) house flies, Musca domestica, and stable flies, Stomoxys calcitrans. In 6-wk field trials, average densities of house and stable fly maggots in concrete mix sand ranged from only .3 to 1.6 and 0 to .1 maggots/L, respectively; pea size gravel bedding also strongly suppressed densities from less than .1 to .3 and less than .1 to .1 maggots/L, respectively. These densities represent reductions of 76 to greater than 99% relative to straw bedding, but both sand and gravel compacted and became soiled with calf feces, which resulted in unacceptable bedding sanitation and foul odors. Densities of house and stable fly maggots in pine shavings did not differ from those in straw bedding. Nevertheless, in sawdust bedding, maggot density was limited to averages of 1.4 to 8.3 house and 9.8 to 11.8 stable fly maggots/L; this represented reductions of 45 to 91% relative to straw. In a follow-up trial, house and stable fly maggot densities in sawdust averaged 11.3 and 43.9 maggots/L, respectively, reductions of 77 and 46%. These findings suggest that bedding calf hutches with sawdust during warm weather can be useful as an ecologically sound approach to controlling muscoid fly populations on dairy farms.

  9. A laboratory experiment on the evolution of a sand gravel reach under a lack of sediment supply

    NARCIS (Netherlands)

    Orru, C.; Chavarrias Borras, V.; Ferrara, V.; Stecca, G.; Blom, A.

    2015-01-01

    A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. A bed composed of a bimodal sediment mixture was installed with a uniform slope and an gradual fining pattern. At the upstream end of the flume the initial bed consisted of 100% gravel,

  10. Large submarine sand waves and gravel lag substrates on Georges Bank off Atlantic Canada

    Science.gov (United States)

    Todd, B.J.; Valentine, Page C.; Harris, Peter T; Baker, E.K.

    2012-01-01

    Georges Bank is a large, shallow, continental shelf feature offshore of New England and Atlantic Canada. The bank is mantled with a veneer of glacial debris transported during the late Pleistocene from continental areas lying to the north. These sediments were reworked by marine processes during postglacial sea-level transgression and continue to be modified by the modern oceanic regime. The surficial geology of the Canadian portion of the bank is a widespread gravel lag overlain in places by well sorted sand occurring as bedforms. The most widespread bedforms are large, mobile, asymmetrical sand waves up to 19 m in height formed through sediment transport by strong tidal-driven and possibly storm-driven currents. Well-defined curvilinear bedform crests up to 15 km long form a complex bifurcating pattern having an overall southwest–northeast strike, which is normal to the direction of the major axis of the semidiurnal tidal current ellipse. Minor fields of immobile, symmetrical sand waves are situated in bathymetric lows. Rare mobile, asymmetrical barchan dunes are lying on the gravel lag in areas of low sand supply. On Georges Bank, the management of resources and habitats requires an understanding of the distribution of substrate types, their surface dynamics and susceptibility to movement, and their associated fauna.

  11. Sodium fire aerosol loading capacity of several sand and gravel filters

    International Nuclear Information System (INIS)

    Barreca, J.R.; McCormack, J.D.

    1980-04-01

    Improved specific loading capacity for sodium fire aerosols was the objective of a sand and gravel test series. The aerosol capacity and related differential pressure of eight aggregate filters is presented. A maximum specific aerosol capacity, for dry aerosol, of 2.4 kg (Na) m -2 was obtained. This filter was loaded to a final differential pressure of 2.6 kPa. The average superficial face velocity was 0.5 cm/s and the average efficiency was 99.8%. The test results indicate that filter capacity increases with aerosol moisture content and with decreasing superficial velocity

  12. A Laboratory Experiment on the Evolution of a Sand Gravel Reach Under a Lack of Sediment Supply

    Science.gov (United States)

    Orru, C.; Chavarrias, V.; Ferrara, V.; Blom, A.

    2014-12-01

    A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. The experimental data are used to validate a numerical sand-gravel model. A bed composed of a bi-modal sediment mixture is installed with a uniform slope and an imposed gradual fining pattern. Initially, the sand fraction gradually increases in streamwise direction until the bed is fully composed of sand. The water discharge and downstream water level were constant, and the sediment feed rate was equal to zero. The experiment was dominated by bed load, partial transport, and a subcritical flow regime was imposed. The flow rate was such that only sand was mobile (partial transport), which led to a coarsening over the upstream reach and a gradual reduction of the sediment transport rate during the experiment. New equipment was used to measure the evolution of the grain size distribution of the bed surface during the experiment over the entire flume using image analysis. In the upstream reach we observed a gradual coarsening over time and the formation of an armour layer, which resulted in a more abrupt transition in grain size of the bed surface. Bed degradation increased in streamwise direction. This is due to the initial streamwise increase in the availability of sand in the bed. The different volume fraction content of sand in the bed allowed for the gravel to sink more in the downstream part of the upstream reach. The sand reach suffered from a larger degradation. Finally, we see one reach dominated by sand, small bedforms, and a small bed slope, and a gravel reach dominated by a larger bed slope.

  13. Chapter J: Issues and challenges in the application of geostatistics and spatial-data analysis to the characterization of sand-and-gravel resources

    Science.gov (United States)

    Hack, Daniel R.

    2005-01-01

    as common drilling methods jeopardizing the accuracy of the size-distribution curve, the application of formal geostatistical principles has other limitations. Many of the variables used in evaluating gravel deposits, including such sedimentologic parameters as sorting and such United Soil Classification System parameters as gradation coefficient, are nonadditive. Also, uniform sampling methods, such as drilling, are relatively uncommon, and sampling is generally accomplished by a combination of boreholes, water-well logs, test pits, trenches, stratigraphic columns from exposures, and, possibly, some geophysical cross sections. When evaluated in consideration of the fact that uniform mining blocks are also uncommon in practice, subsequent complexities in establishment of the volume/variance relation are inevitable. Several approaches exist to confront the limitations of geostatistical methods in evaluating sand-and-gravel deposits. Initially, we must acknowledge the practical requirements of the aggregate industry, as well as the limitations of the data collected by that industry, as a function of what the industry requires at the practical level, and consider that broader acceptance of formal geostatistics may require modifications of typical exploration and sampling protocols. Future investigations should utilize data from the full spectrum of sand-and-gravel deposits (flood plain, glacial, catastrophic flood, and marine), integrate such other disci plines as sedimentology and geophysics into the research, develop commodity-specific approaches to nonadditive variables, and include the results of comparative drilling.

  14. The morphology and morphodynamics of sand-gravel subaquatic dunes: the Raba River estuary, Poland

    Directory of Open Access Journals (Sweden)

    Artur RADECKI-PAWLIK

    2012-08-01

    Full Text Available In the outlet of the Raba River to the Vistula, the biggest river in Poland, the morphology and morphodynamics of sand and fine-gravel subaquatic dunes were investigated. The site is situated in highland region just about the entrance to Polish Carpathians. The dunes formed on the Raba River bed estuary are composed of sand and fine gravel (d50 up to 11 mm. Systematic observation (within the 2000-2005 were made of geometry, sediment composition and hydraulic climate under which the dunes grew and decomposed. The investigation focuses here mostly on the geometrical parameters of these bed forms such as height, length, as well as granulometric characteristics of the sediment. Based on in-site measurements different hydraulic parameters were calculated such as shear stresses, resistant coefficient, Froude and Reynolds numbers and roughness coefficient. It was found that the relation between height (H and length (L of the Raba estuary dunes describes the formula: H = 0.05L0.35. Also these dunes are steeper and flatter then classical H/L index is: H/L = 0.0518L0.622. During the field campaign, when the foot access to the estuary was possible and dunes were spotted on the river bed the range of measured water velocity was from v = 0.39 m∙s-1 to v = 0.81 m∙s-1 with the highest velocity over the dune crest. At the same time the measured range of shear stresses within the dune field formation were from t = 0.115 N×m-2 to t = 1.59 N×m-2. On the field investigations the CCHE2D - two-dimensional unsteady flow and sediment transport model for non-equilibrium transport of non-uniform sediment mixtures – was applied. The model was used to simulate the morphodynamic changes along the outlet of the Raba River basing on field observations of the 2005 summer flood as well as calculate hydraulics parameters. It was also used to test and confirm the range of morphodynamic changes, which take place along the research reach where the dunes are being developed

  15. Performance evaluation and modelling studies of gravel--coir fibre--sand multimedia stormwater filter.

    Science.gov (United States)

    Samuel, Manoj P; Senthilvel, S; Tamilmani, D; Mathew, A C

    2012-09-01

    A horizontal flow multimedia stormwater filter was developed and tested for hydraulic efficiency and pollutant removal efficiency. Gravel, coconut (Cocos nucifera) fibre and sand were selected as the media and filled in 1:1:1 proportion. A fabric screen made up of woven sisal hemp was used to separate the media. The adsorption behaviour of coir fibre was determined in a series of column and batch studies and the corresponding isotherms were developed. The hydraulic efficiency of the filter showed a diminishing trend as the sediment level in inflow increased. The filter exhibited 100% sediment removal at lower sediment concentrations in inflow water (>6 g L(-1)). The filter could remove NO3(-), SO4(2-) and total solids (TS) effectively. Removal percentages of Mg(2+) and Na(+) were also found to be good. Similar results were obtained from a field evaluation study. Studies were also conducted to determine the pattern of silt and sediment deposition inside the filter body. The effects of residence time and rate of flow on removal percentages of NO3(-) and TS were also investigated out. In addition, a multiple regression equation that mathematically represents the filtration process was developed. Based on estimated annual costs and returns, all financial viability criteria (internal rate of return, net present value and benefit-cost ratio) were found favourable and affordable to farmers for investment in the developed filtration system. The model MUSIC was calibrated and validated for field conditions with respect to the developed stormwater filter.

  16. Migration rates of volatile organic compounds in an unconsolidated sand and gravel aquifer system

    International Nuclear Information System (INIS)

    Naidu, J.R.; Paquette, D.E.; Porcelli, D.R.

    1993-01-01

    The movement of volatile organic compounds (VOCs) in an aquifer is dictated by its solubility, attenuation characteristics, recharge volume, and ground-water movement (velocity and direction). At Brookhaven National Laboratory, past handling and disposal practices at the Hazardous Waste Management Facility and current landfill have resulted in the release of VOCs and the radioisotope tritium to the underlying upper glacial aquifer which characterized by unconsolidated sands and gravel. The rate of VOC migration from these source areas was examined using the following parameters: (1) distribution of VOCs and tritium; (2) tritium/helium ratios, which provide an estimate of the age of the water, and hence the rate of ground-water movement; (3) ground-water flow velocities within the upper glacial aquifer utilizing conductivity, porosity, and gradient data. Preliminary results indicate that whereas the comparison of the calculated ground-water flow gradient to tritium/helium age determinations are fairly consistent, application to VOC movement is inconclusive, and will require additional monitoring which would also focus on the vertical component as well

  17. Deposition of Suspended Clay to Open and Sand-Filled Framework Gravel Beds in a Laboratory Flume

    Science.gov (United States)

    Mooneyham, Christian; Strom, Kyle

    2018-01-01

    Pulses of fine sediment composed of sand, silt, and clay can be introduced to gravel bed rivers through runoff from burn-impacted hillslopes, landslides, bank failure, or the introduction of reservoir sediment as a result of sluicing or dam decommissioning. Here we present a study aimed at quantifying exchange between suspensions of clay and gravel beds. The questions that motivate the work are: how do bed roughness and pore space characteristics, shear velocity (u∗), and initial concentration (C0) affect clay deposition on or within gravel beds? Where does deposition within these beds occur, and can deposited clay be resuspended while the gravel is immobile? We examine these questions in a laboratory flume using acrylic, open-framework gravel, and armored sand-gravel beds under conditions of varying u∗ and C0. Deposition of clay occurred to all beds (even with Rouse numbers ˜ 0.01). We attribute deposition under full suspension conditions to be an outcome of localized protected zones where clay can settle and available pore space in the bed. For smooth wall cases, protection came from the viscous wall region and the development of bed forms; for the rough beds, protection came from separation zones and low-velocity pore spaces. Bed porosity was the strongest influencer of nondimensional deposition rate; deposition increased with porosity. Deposition was inversely related to u∗ for the acrylic bed runs; no influence of u∗ was found for the porous bed runs. Increases in discharge resulted in resuspension of clay from acrylic beds; no resuspension was observed in the porous bed runs.

  18. The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer

    Science.gov (United States)

    Morin, Roger H.; LeBlanc, Denis R.; Troutman, Brent M.

    2010-01-01

    A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand-and-gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ϕ, hydraulic conductivity K, temperature, and bulk electrical conductivity under background, freshwater conditions. Saline-tracer fluid was then injected into the well for 2 h and its radial migration into the surrounding deposits was monitored by recording an electromagnetic-induction log every 10 min. The field data are analyzed and interpreted primarily through the use of Archie's (1942) law to investigate the role of topological factors such as pore geometry and connectivity, and grain size and packing configuration in regulating fluid flow through these coarse-grained materials. The logs reveal no significant correlation between K and ϕ, and imply that groundwater models that link these two properties may not be useful at this site. Rather, it is the distribution and connectivity of the fluid phase as defined by formation factor F, cementation index m, and tortuosity α that primarily control the hydraulic conductivity. Results show that F correlates well with K, thereby indicating that induction logs provide qualitative information on the distribution of hydraulic conductivity. A comparison of α, which incorporates porosity data, with K produces only a slightly better correlation and further emphasizes the weak influence of the bulk value of ϕ on K.

  19. Hydraulic characterisation of iron-oxide-coated sand and gravel based on nuclear magnetic resonance relaxation mode analyses

    Directory of Open Access Journals (Sweden)

    S. Costabel

    2018-03-01

    Full Text Available The capability of nuclear magnetic resonance (NMR relaxometry to characterise hydraulic properties of iron-oxide-coated sand and gravel was evaluated in a laboratory study. Past studies have shown that the presence of paramagnetic iron oxides and large pores in coarse sand and gravel disturbs the otherwise linear relationship between relaxation time and pore size. Consequently, the commonly applied empirical approaches fail when deriving hydraulic quantities from NMR parameters. Recent research demonstrates that higher relaxation modes must be taken into account to relate the size of a large pore to its NMR relaxation behaviour in the presence of significant paramagnetic impurities at its pore wall. We performed NMR relaxation experiments with water-saturated natural and reworked sands and gravels, coated with natural and synthetic ferric oxides (goethite, ferrihydrite, and show that the impact of the higher relaxation modes increases significantly with increasing iron content. Since the investigated materials exhibit narrow pore size distributions, and can thus be described by a virtual bundle of capillaries with identical apparent pore radius, recently presented inversion approaches allow for estimation of a unique solution yielding the apparent capillary radius from the NMR data. We found the NMR-based apparent radii to correspond well to the effective hydraulic radii estimated from the grain size distributions of the samples for the entire range of observed iron contents. Consequently, they can be used to estimate the hydraulic conductivity using the well-known Kozeny–Carman equation without any calibration that is otherwise necessary when predicting hydraulic conductivities from NMR data. Our future research will focus on the development of relaxation time models that consider pore size distributions. Furthermore, we plan to establish a measurement system based on borehole NMR for localising iron clogging and controlling its remediation

  20. Hydraulic characterisation of iron-oxide-coated sand and gravel based on nuclear magnetic resonance relaxation mode analyses

    Science.gov (United States)

    Costabel, Stephan; Weidner, Christoph; Müller-Petke, Mike; Houben, Georg

    2018-03-01

    The capability of nuclear magnetic resonance (NMR) relaxometry to characterise hydraulic properties of iron-oxide-coated sand and gravel was evaluated in a laboratory study. Past studies have shown that the presence of paramagnetic iron oxides and large pores in coarse sand and gravel disturbs the otherwise linear relationship between relaxation time and pore size. Consequently, the commonly applied empirical approaches fail when deriving hydraulic quantities from NMR parameters. Recent research demonstrates that higher relaxation modes must be taken into account to relate the size of a large pore to its NMR relaxation behaviour in the presence of significant paramagnetic impurities at its pore wall. We performed NMR relaxation experiments with water-saturated natural and reworked sands and gravels, coated with natural and synthetic ferric oxides (goethite, ferrihydrite), and show that the impact of the higher relaxation modes increases significantly with increasing iron content. Since the investigated materials exhibit narrow pore size distributions, and can thus be described by a virtual bundle of capillaries with identical apparent pore radius, recently presented inversion approaches allow for estimation of a unique solution yielding the apparent capillary radius from the NMR data. We found the NMR-based apparent radii to correspond well to the effective hydraulic radii estimated from the grain size distributions of the samples for the entire range of observed iron contents. Consequently, they can be used to estimate the hydraulic conductivity using the well-known Kozeny-Carman equation without any calibration that is otherwise necessary when predicting hydraulic conductivities from NMR data. Our future research will focus on the development of relaxation time models that consider pore size distributions. Furthermore, we plan to establish a measurement system based on borehole NMR for localising iron clogging and controlling its remediation in the gravel pack of

  1. Suitability of parametric models to describe the hydraulic properties of an unsaturated coarse sand and gravel

    Science.gov (United States)

    Mace, Andy; Rudolph, David L.; Kachanoski , R. Gary

    1998-01-01

    The performance of parametric models used to describe soil water retention (SWR) properties and predict unsaturated hydraulic conductivity (K) as a function of volumetric water content (θ) is examined using SWR and K(θ) data for coarse sand and gravel sediments. Six 70 cm long, 10 cm diameter cores of glacial outwash were instrumented at eight depths with porous cup ten-siometers and time domain reflectometry probes to measure soil water pressure head (h) and θ, respectively, for seven unsaturated and one saturated steady-state flow conditions. Forty-two θ(h) and K(θ) relationships were measured from the infiltration tests on the cores. Of the four SWR models compared in the analysis, the van Genuchten (1980) equation with parameters m and n restricted according to the Mualem (m = 1 - 1/n) criterion is best suited to describe the θ(h) relationships. The accuracy of two models that predict K(θ) using parameter values derived from the SWR models was also evaluated. The model developed by van Genuchten (1980) based on the theoretical expression of Mualem (1976) predicted K(θ) more accurately than the van Genuchten (1980) model based on the theory of Burdine (1953). A sensitivity analysis shows that more accurate predictions of K(θ) are achieved using SWR model parameters derived with residual water content (θr) specified according to independent measurements of θ at values of h where θ/h ∼ 0 rather than model-fit θr values. The accuracy of the model K(θ) function improves markedly when at least one value of unsaturated K is used to scale the K(θ) function predicted using the saturated K. The results of this investigation indicate that the hydraulic properties of coarse-grained sediments can be accurately described using the parametric models. In addition, data collection efforts should focus on measuring at least one value of unsaturated hydraulic conductivity and as complete a set of SWR data as possible, particularly in the dry range.

  2. Reservoir architecture patterns of sandy gravel braided distributary channel

    Directory of Open Access Journals (Sweden)

    Senlin Yin

    2016-06-01

    Full Text Available The purpose of this study was to discuss shape, scale and superimposed types of sandy gravel bodies in sandy-gravel braided distributary channel. Lithofacies analysis, hierarchy bounding surface analysis and subsurface dense well pattern combining with outcrops method were used to examine reservoir architecture patterns of sandy gravel braided distributary channel based on cores, well logging, and outcrops data, and the reservoir architecture patterns of sandy gravel braided distributary channels in different grades have been established. The study shows: (1 The main reservoir architecture elements for sandy gravel braided channel delta are distributary channel and overbank sand, while reservoir flow barrier elements are interchannel and lacustrine mudstone. (2 The compound sand bodies in the sandy gravel braided delta distributary channel take on three shapes: sheet-like distributary channel sand body, interweave strip distributary channel sand body, single strip distributary channel sand body. (3 Identification marks of single distributary channel include: elevation of sand body top, lateral overlaying, “thick-thin-thick” feature of sand bodies, interchannel mudstone and overbank sand between distributary channels and the differences in well log curve shape of sand bodies. (4 Nine lithofacies types were distinguished in distributary channel unit interior, different channel units have different lithofacies association sequence.

  3. Septic systems as sources of organic wastewater compounds in domestic drinking water wells in a shallow sand and gravel aquifer.

    Science.gov (United States)

    Schaider, Laurel A; Ackerman, Janet M; Rudel, Ruthann A

    2016-03-15

    Domestic drinking water wells serve 44 million people in the US and are common globally. They are often located in areas served by onsite wastewater treatment systems, including septic systems, which can be sources of biological and chemical pollutants to groundwater. In this study we tested 20 domestic drinking water wells in a sand and gravel aquifer on Cape Cod, Massachusetts, USA, for 117 organic wastewater compounds (OWCs) and for inorganic markers of septic system impact. We detected 27 OWCs, including 12 pharmaceuticals, five per- and polyfluoroalkyl substances (PFASs), four organophosphate flame retardants, and an artificial sweetener (acesulfame). Maximum concentrations of several PFASs and pharmaceuticals were relatively high compared to public drinking water supplies in the US. The number of detected OWCs and total concentrations of pharmaceuticals and of PFASs were positively correlated with nitrate, boron, and acesulfame and negatively correlated with well depth. These wells were all located in areas served exclusively by onsite wastewater treatment systems, which are likely the main source of the OWCs in these wells, although landfill leachate may also be a source. Our results suggest that current regulations to protect domestic wells from pathogens in septic system discharges do not prevent OWCs from reaching domestic wells, and that nitrate, a commonly measured drinking water contaminant, is a useful screening tool for OWCs in domestic wells. Nitrate concentrations of 1mg/L NO3-N, which are tenfold higher than local background and tenfold lower than the US federal drinking water standard, were associated with wastewater impacts from OWCs in this study. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Septic systems as sources of organic wastewater compounds in domestic drinking water wells in a shallow sand and gravel aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Schaider, Laurel A., E-mail: schaider@silentspring.org; Ackerman, Janet M.; Rudel, Ruthann A.

    2016-03-15

    Domestic drinking water wells serve 44 million people in the US and are common globally. They are often located in areas served by onsite wastewater treatment systems, including septic systems, which can be sources of biological and chemical pollutants to groundwater. In this study we tested 20 domestic drinking water wells in a sand and gravel aquifer on Cape Cod, Massachusetts, USA, for 117 organic wastewater compounds (OWCs) and for inorganic markers of septic system impact. We detected 27 OWCs, including 12 pharmaceuticals, five per- and polyfluoroalkyl substances (PFASs), four organophosphate flame retardants, and an artificial sweetener (acesulfame). Maximum concentrations of several PFASs and pharmaceuticals were relatively high compared to public drinking water supplies in the US. The number of detected OWCs and total concentrations of pharmaceuticals and of PFASs were positively correlated with nitrate, boron, and acesulfame and negatively correlated with well depth. These wells were all located in areas served exclusively by onsite wastewater treatment systems, which are likely the main source of the OWCs in these wells, although landfill leachate may also be a source. Our results suggest that current regulations to protect domestic wells from pathogens in septic system discharges do not prevent OWCs from reaching domestic wells, and that nitrate, a commonly measured drinking water contaminant, is a useful screening tool for OWCs in domestic wells. Nitrate concentrations of 1 mg/L NO{sub 3}-N, which are tenfold higher than local background and tenfold lower than the US federal drinking water standard, were associated with wastewater impacts from OWCs in this study. - Highlights: • We tested 20 domestic drinking water wells for 117 organic wastewater compounds. • PFASs, pharmaceuticals, and an artificial sweetener were most frequently detected. • Nitrate, boron, and well depth were all correlated with PFASs and pharmaceuticals. • Acesulfame

  5. Septic systems as sources of organic wastewater compounds in domestic drinking water wells in a shallow sand and gravel aquifer

    International Nuclear Information System (INIS)

    Schaider, Laurel A.; Ackerman, Janet M.; Rudel, Ruthann A.

    2016-01-01

    Domestic drinking water wells serve 44 million people in the US and are common globally. They are often located in areas served by onsite wastewater treatment systems, including septic systems, which can be sources of biological and chemical pollutants to groundwater. In this study we tested 20 domestic drinking water wells in a sand and gravel aquifer on Cape Cod, Massachusetts, USA, for 117 organic wastewater compounds (OWCs) and for inorganic markers of septic system impact. We detected 27 OWCs, including 12 pharmaceuticals, five per- and polyfluoroalkyl substances (PFASs), four organophosphate flame retardants, and an artificial sweetener (acesulfame). Maximum concentrations of several PFASs and pharmaceuticals were relatively high compared to public drinking water supplies in the US. The number of detected OWCs and total concentrations of pharmaceuticals and of PFASs were positively correlated with nitrate, boron, and acesulfame and negatively correlated with well depth. These wells were all located in areas served exclusively by onsite wastewater treatment systems, which are likely the main source of the OWCs in these wells, although landfill leachate may also be a source. Our results suggest that current regulations to protect domestic wells from pathogens in septic system discharges do not prevent OWCs from reaching domestic wells, and that nitrate, a commonly measured drinking water contaminant, is a useful screening tool for OWCs in domestic wells. Nitrate concentrations of 1 mg/L NO_3-N, which are tenfold higher than local background and tenfold lower than the US federal drinking water standard, were associated with wastewater impacts from OWCs in this study. - Highlights: • We tested 20 domestic drinking water wells for 117 organic wastewater compounds. • PFASs, pharmaceuticals, and an artificial sweetener were most frequently detected. • Nitrate, boron, and well depth were all correlated with PFASs and pharmaceuticals. • Acesulfame (artificial

  6. Sand and gravel spits

    CERN Document Server

    Randazzo, Giovanni; Cooper, J Andrew G

    2015-01-01

    This book draws together a series of studies of spit geomorphology and temporal evolution from around the world. The volume offers some unique insights into how these landforms are examined scientifically and how we as humans impact them, offering a global perspective on spit genesis and evolution. Spits are unique natural environments whose evolution is linked to the adjacent coast and near shore morphology, sediment supply, coastal dynamics and sea-level change. Over the past century, Global Mean Sea Level (GMSL) has risen by 10 to 20 centimetres and many coastal spits represent the first sentinel against coastal submersion. Scientific research indicates that sea levels worldwide have been rising at a rate of 3.5 millimetres per year since the early 1990s, roughly twice the average speed of the preceding 80 years. This trend, linked to global warming will undoubtedly cause major changes in spit morphology. Spits are highly mobile coastal landforms that respond rapidly to environmental change. They therefore...

  7. Used Furan Sand Reclamation in REGMAS Vibratory Unit

    Directory of Open Access Journals (Sweden)

    Dańko J.

    2015-09-01

    Full Text Available The paper, especially dealt with problems of reclamation of used furan sand, carried out in new, vibratory sand reclamation unit REGMAS developed by researches from AGH-University of Science and Technology, Faculty of Foundry Engineering in Cracow (Poland. Functional characteristics of reclamation unit as well as the results of reclamation of used sand with furfuryl resin are discussed in the paper. The quality of reclaim was tested by means of the LOI and pH value, dust content in the reclaim and at least by the the quality of the castings produced in moulds prepared with the use of reclaimed matrix.

  8. Hydrogeology and water quality of sand and gravel aquifers in McHenry County, Illinois, 2009-14, and comparison to conditions in 1979

    Science.gov (United States)

    Gahala, Amy M.

    2017-10-26

    Baseline conditions for the sand and gravel aquifers (groundwater) in McHenry County, Illinois, were assessed using data from a countywide network of 44 monitoring wells collecting continuous water-level data from 2009–14. In 2010, water-quality data were collected from 41 of the monitoring wells, along with five additional monitoring wells available from the U.S. Geological Survey National Water Quality Assessment Program. Periodic water-quality data were collected from 2010–14 from selected monitoring wells. The continuous water-level data were used to identify the natural and anthropogenic factors that influenced the water levels at each well. The water-level responses to natural influences such as precipitation, seasonal and annual variations, barometric pressure, and geology, and to anthropogenic influences such as pumping were used to determine (1) likely hydrogeologic setting (degree of aquifer confinement and interconnections) that, in part, are related to lithostratigraphy; and (2) areas of recharge and discharge related to vertical flow directions. Water-level trends generally were determined from the 6 years of data collection (2009–14) to infer effects of weather variability (drought) on recharge.Precipitation adds an estimated 2.4 inches per year of recharge to the aquifer. Some of this recharge is subsequently discharged to streams and some is discharged to supply wells. A few areas in the eastern half of the county had higher average recharge rates, indicating a need for adequate protection of these recharge areas. Downward vertical flow gradients in upland areas indicate that recharge to the confined aquifer units occurs near upland areas. Upward vertical flow gradients in lowland areas indicate discharge at locations of surface water and groundwater interaction (wetlands, ponds, and streams).Monitoring wells were sampled for major and minor ions, metals, and nutrients and a subset of wells was sampled for trace elements, dissolved gases

  9. Genesis and continuity of quaternary sand and gravel in glacigenic sediment at a proposed low-level radioactive waste disposal site in east-central Illinois

    Science.gov (United States)

    Troost, K.G.; Curry, B. Brandon

    1991-01-01

    The Illinois Department of Nuclear Safety has characterized the Martinsville Alternative Site (MAS) for a proposed low-level radioactive waste disposal facility. The MAS is located in east-central Illinois approximately 1.6 km (1 mi) north of the city of Martinsville. Geologic investigation of the 5.5-km2 (1380-acre) site revealed a sequence of chiefly Illinoian glacigenic sediments from 6 to 60 m (20-200 ft) thick overlying two major bedrock valleys carved in Pennsylvanian strata. Relatively permeable buried units include basal, preglacial alluvium; a complex of intraglacial and subglacial sediment; englacial deposits; and supraglacial fluvial deposits. Postglacial alluvium underlies stream valleys on and adjacent to the site. In most areas, the buried sand units are confined by low-permeability till, lacustrine sediment, colluvium, and loess. The distribution and thickness of the most extensive and continuous buried sand units have been modified considerably by subglacial erosion, and their distributions have been influenced by the buried bedrock valleys. The most continuous of the various sand units were deposited as preglacial and postglacial alluvium and are the uppermost and lowermost stratigraphic units at the alternative site. Sand units that were deposited in englacial or ice-marginal environments are less continuous. Aquifer pumping tests, potentiometric head data, and groundwater geochemistry analyses indicate minimal interaction of groundwater across localized interconnections of the permeable units. ?? 1991 Springer-Verlag New York Inc.

  10. Plant growth evaluation of Cajanus cajan (L. Millsp., Canavalia ensiformis (L. DC. and Cratylia argentea (Desvaux O. Kuntze., in soils degraded by sand and gravel extraction

    Directory of Open Access Journals (Sweden)

    Mateo Vargas Zapata

    2017-10-01

    Full Text Available In this research, the adaptability of pigeon pea (Cajanus cajan (L. Millsp., canavalia (Canavalia ensiformis (L. DC. and veranera (Cratylia argentea (Desvaux O. Kuntze species, was evaluated in soils degraded by sand and gravel extraction. The three species were planted in bags as follows: 20 x 10cm, each with 3 seeds, with a substrate 2:1 soil and sand, respectively. The plants were grown under shadow conditions with 50% for 60 days, and received irrigation according to climate conditions. Therefore, were transplanted at field conditions, plant height (PH, fully developed leaves (FDL and stem diameter (SD variables, were measured every week for 10 weeks. A randomized block design was used with a fixed balanced effect. The number of replicates per treatment was four, the multivariate technique MANOVA variance with orthogonal type was included and the method of maximum likelihood was used to establish the dimensionality of the contrast. In fact, one-dimensional comparisons were carried out using Tukey method, which had achieved type I error of 5% statistical significance. Significant difference among plants for PH (p<0.05 variable was obtained. In addition, SD variable showed differences from the third week for all evaluated plants (p<0.05. A highly significant and directly proportional relationship among HP, FDL and SD variables (p<0.0001, was found. MANOVA Multivariate Analysis showed a highly significant difference among evaluated species (p<0.0001, which confirms the hypothesis. It was expected that species were developing and growing despite having contrasting conditions in the study area.

  11. The in-situ decontamination of sand and gravel aquifers by chemically enhanced solubilization of multiple-component DNAPLS with surfactant solutions. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-01

    Laboratory, numerical simulation, and field studies have been conducted to assess the potential use of micellar-surfactant solutions to solubilize chlorinated solvents contaminating sand and gravel aquifers. Laboratory studies were conducted at the State University of New York at Buffalo (SUNY) while numerical simulation and field work were undertaken by INTERA Inc. in collaboration with Martin Marietta Energy Systems Inc. at the Paducah Gaseous Diffusion Plant (PGDP) in Kentucky. Ninety-nine surfactants were screened for their ability to solubilize trichloroethene (TCE), perchloroethylene (PCE), and carbon tetrachloride (CTET). Ten of these were capable of solubilizing TCE to concentrations greater than 15,000 mg/L, compared to its aqueous solubility of 1,100 mg/L. Four surfactants were identified as good solubilizers of all three chlorinated solvents. Of these, a secondary alcohol ethoxylate was the first choice for in situ testing because of its excellent solubilizing ability and its low propensity to sorb. However, this surfactant did not meet the Commonwealth of Kentucky`s acceptance criteria. Consequently, it was decided to use a surfactant approved for use by the Food and Drug Administration as a food-grade additive. As a 1% micellar-surfactant solution, this sorbitan monooleate has a solubilization capacity of 16,000 mg TCE/L, but has a higher propensity to sorb to clays than has the alcohol ethoxylate.

  12. Inverse Porosity-Hydraulic Conductivity Relationship in Sand-and-Gravel Aquifers Determined From Analysis of Geophysical Well Logs: Implications for Transport Processes

    Science.gov (United States)

    Morin, R. H.

    2004-05-01

    It is intuitive to think of hydraulic conductivity K as varying directly and monotonically with porosity P in porous media. However, laboratory studies and field observations have documented a possible inverse relationship between these two parameters in unconsolidated deposits under certain grain-size distributions and packing arrangements. This was confirmed at two sites in sand-and-gravel aquifers on Cape Cod, Massachusetts, where sets of geophysical well logs were used to examine the interdependence of several aquifer properties. Along with K and P, the resistivity R and the natural-gamma activity G of the surrounding sediments were measured as a function of depth. Qualitative examination of field results from the first site was useful in locating a contaminant plume and inferred an inverse relation between K and P; this was substantiated by a rigorous multivariate analysis of log data collected from the second site where K and P were determined to respond in a bipolar manner among the four independent variables. Along with this result come some implications regarding our conceptual understanding of contaminant transport processes in the shallow subsurface. According to Darcy's law, the interstitial fluid velocity V is proportional to the ratio K/P and, consequently, a general inverse K-P relationship implies that values of V can extend over a much wider range than conventionally assumed. This situation introduces a pronounced flow stratification within these granular deposits that can result in large values of longitudinal dispersivity; faster velocities occur in already fast zones and slower velocities in already slow zones. An inverse K-P relationship presents a new perspective on the physical processes associated with groundwater flow and transport. Although the results of this study apply strictly to the Cape Cod aquifers, they may merit a re-evaluation of modeling approaches undertaken at other locations having similar geologic environments.

  13. Central receiver solar thermal power system, Phase 1. CDRL Item 2. Pilot plant preliminary design report. Volume V. Thermal storage subsystem. [Sensible heat storage using Caloria HT43 and mixture of gravel and sand

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The proposed 100-MWe Commercial Plant Thermal Storage System (TSS) employs sensible heat storage using dual liquid and solid media for the heat storage in each of four tanks, with the thermocline principle applied to provide high-temperature, extractable energy independent of the total energy stored. The 10-MW Pilot Plant employs a similar system except uses only a single tank. The high-temperature organic fluid Caloria HT43 and a rock mixture of river gravel and No. 6 silica sand were selected for heat storage in both systems. The system design, installation, performance testing, safety characteristics, and specifications are described in detail. (WHK)

  14. Frac sand in the United States: a geological and industry overview

    Science.gov (United States)

    Benson, Mary Ellen; Wilson, Anna B.; Bleiwas, Donald I.

    2015-01-01

    A new mineral rush is underway in the upper Midwest of the United States, especially in Wisconsin and Minnesota, for deposits of high-quality frac sand that the mining industry calls “Northern White” sand or “Ottawa” sand. Frac sand is a specialized type of sand that is added to fracking fluids that are injected into unconventional oil and gas wells during hydraulic fracturing (fracking or hydrofracking), a process that enhances petroleum extraction from tight (low permeability) reservoirs. Frac sand consists of natural sand grains with strict mineralogical and textural specifications that act as a proppant (keeping induced fractures open), extending the time of release and the flow rate of hydrocarbons from fractured rock surfaces in contact with the wellbore.

  15. 深厚砂砾石地层固结灌浆在实际工程中的应用%Consolidation Grouting of Deep Sand-gravel Stratum in Practical Engineering Application

    Institute of Scientific and Technical Information of China (English)

    赵健飞

    2014-01-01

    水利工程施工过程中,经常会遇到水工建筑物直接修建在砂砾石地层上,为了提高砂砾石地层的整体性、密实性并降低其透水率,一般需要对坝基采取全面的固结灌浆,必要时也在坝基上、下游一定范围内进行固结灌浆。结合水利枢纽的工程实践,对泄洪冲沙闸底板进行全面的固结灌浆处理,施工过程中采用自上而下分段灌浆方法,对现有的钻探与灌浆工艺技术进行优化组合,最终经灌后质量检查,结果满足深厚砂砾石覆盖层固结灌浆的设计要求,取得了良好的效果。%In the construction of hydraulic engineering projects ,the hydraulic structures are often directly built on the sand gravel stratum .In order to improve the integrity of sandy gravel stratum and reduce its permeability ,it is common to apply comprehensive consolidation grouting on the dam foundation ,sometimes consolidation grouting is also carried out in a certain range of the upstream and downstream of the dam foundation when necessary .In the construction of an engineer-ing project ,the comprehensive consolidation grouting was applied on the floor of the outlet sluice with descending stage grouting method during the construction process .This method combined the advantages of the existing drilling and grout-ing techniques and reached a optimum combination .The result of the quality inspection indicates that the outcome not on-ly meets the specifications of consolidation grouting of deep sand gravel stratum ,but also has excellent performance .

  16. Value of Canadian oil sands... to the United States

    International Nuclear Information System (INIS)

    Pugliaresi, Lucian

    2011-01-01

    Since the beginning of the recession in late 2007, the American economy has been subject to great change, affecting the way energy is produced and consumed. The structure of oil imports and exports has changed significantly and U.S. imports are now primarily from Canada. The current study shows how and why the U.S. has become dependent on imports of oil from the Canadian oil sands. Oil from Canadian oil sands is transported to different Petroleum Administration for Defense Districts (PADD) via the Keystone pipeline. As imports from Canada increased, the U.S. refinery sector was restructured. Small refineries were closed while larger refineries were expanded and investment was made to increase their processing capacity. The increased import and processing of oil from the Canadian oil sands led to an advantageous decrease in oil prices. If the Keystone XL project were to be approved, the pipeline would increase the area with access to the means of transporting oil, allowing the increasing demand for oil to be met and, potentially, stabilizing world oil prices.

  17. Interaction of the Bored Sand and Gravel Drain Pile with the Surrounding Compacted Loam Soil and Foundation Raft Taking into Account Rheological Properties of the Loam Soil and Non-Linear Properties of the Drain Pile

    Science.gov (United States)

    Ter-Martirosyan, Z. G.; Ter-Martirosyan, A. Z.; Anzhelo, G. O.; Buslov, A. S.

    2018-01-01

    The task of the interaction of the sand and gravel drain pile with the surrounding loam soil after its preliminary deep compaction and formation of the composite ground cylinder from the drain pile and surrounding compacted loam soil (cells) is considered in the article. It is seen that the subsidence and carrying capacity of such cell considerably depends on physical and mechanical properties of the compacted drain piles and surrounding loam soil as well as their diameter and intercellular distance. The strain-stress state of the cell is considered not taking into account its component elements, but taking into account linear and elastic-plastic properties of the drain pile and creep flow of the surrounding loam soil. It is stated that depending on these properties the distribution and redistribution of the load on a cell takes place from the foundation raft between the drain pile and surrounding soil. Based on the results of task solving the formulas and charts are given demonstrating the ratio of the load between the drain pile and surrounding loam soil in time.

  18. Integrated mined-area reclamation and land use planning. Volume 3A. A case study of surface mining and reclamation planning: South Boulder Creek Park Project, Sand and Gravel Operations, Boulder, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, L R; Perry, A O; LaFevers, J R

    1977-02-01

    This case study details reclamation planning for the Flatiron Companies' South Boulder Creek Park Project in Boulder, Colorado. The site contains a deposit of high-quality sand and gravel considered to be one of the best and largest known deposits of aggregate materials in the Front Range area. The aggregate deposit is located in a highly visible site just off the Denver-Boulder Turnpike at the entrance to the city from Denver, and adjacent to a residential portion of the city. In order to make maximum use of pre-mining planning, as a tool for resolving a conflict over the company's proposed operation, an extensive cooperative planning effort was initiated. This included the preparation of an environmental impact assessment, numerous public hearings, operating and reclamation plan review by city authorities, annexation of the site to the city, and the granting of a scenic easement on the property to the city for the development of a regional recreation park. A suite of contractual agreements was worked out among Flatiron Companies, the City of Boulder, the Colorado Open Lands Foundation, and the Federal Bureau of Outdoor Recreation. The purpose of this case study is to allow the planner to gain insight into the procedures, possibilities, and constraints involved in premining planning in a cooperative situation.

  19. Can coarse surface layers in gravel-bedded rivers be mobilized by finer gravel bedload?

    Science.gov (United States)

    Venditti, J. G.; Dietrich, W. E.; Nelson, P. A.; Wydzga, M. A.; Fadde, J.; Sklar, L.

    2005-12-01

    In response to reductions in sediment supply, gravel-bed rivers undergo a coarsening of the sediments that comprise the river's bed and, over some longer time scale, a river's grade may also be reduced as sediments are depleted from upstream reaches. Coarse, degraded river reaches are commonly observed downstream of dams across the Western United States. Following dam closure, these riverbeds become immobile under the altered flow and sediment supply regimes, leading to a reduction in the available salmon spawning and rearing habitat. Gravel augmentation to these streams is now common practice. This augmentation is typically seen as resurfacing the static coarse bed. As an alternative, we propose that the addition of appropriately finer gravels to these channels may be capable of mobilizing an otherwise immobile coarse surface layer, creating the potential to release fine material trapped beneath the surface. A series of laboratory experiments are being undertaken to test this hypothesis in a 30 m long and 0.86 m wide gravel-bedded flume channel using a constant discharge and a unimodal bed sediment with a median grain size of 8 mm and no sand present. The channel width-to-depth ratio of ~4 suppresses the development of lateral topography and allows us to focus on grain-to-grain interactions. Experiments proceed by maintaining a constant sediment feed until an equilibrium grade and transport rate are established, starving the flume of sediment for at least 24 hours, and then adding narrowly graded gravel over a period of one to two hours at a rate that is ~4x the bedload rate observed prior to terminating the sediment supply. The bed prior to sediment addition has an armor median grain size that is typically twice that of the subsurface and feed size distribution. The volume and median grain size of the resulting pulses are varied. Pulses move downstream rapidly with well-defined fronts in the form of bedload sheets and cause peaks in the sediment flux

  20. Modelação da perda de carga na filtração direta ascendente em meio granular de areia grossa e pedregulho Modeling of the head loss in up flow coarse sand and gravel direct filtration

    Directory of Open Access Journals (Sweden)

    Alexandre Botari

    2009-06-01

    Full Text Available Compreender e quantificar os mecanismos relacionados à perda de carga e à remoção de partículas em um meio filtrante granular é de importância fundamental para o estudo do processo da filtração. Este trabalho apresenta o desenvolvimento dos modelos de perda de carga na filtração em meios porosos e a proposição da modelação matemática semiempírica da perda de carga para meios filtrantes limpos e do desenvolvimento do perfil de perda de carga ao longo do tempo de filtração a partir da equação de Ergun. Objetivou-se a determinação dos valores das constantes da equação de Ergun para meio granular de areia grossa e pedregulho. Alguns exemplos de aplicação dessa modelação matemática são também apresentados e discutidos pelos autores com base em dados experimentais obtidos em uma estação piloto de dupla filtração.To understand and to quantify the head loss due to the particles removal in a porous medium has primary importance to filtration process study. This paper presents the development of the models of head loss used in the filtration in porous media and proposes a mathematical semi-empiric model for head loss in clean beds and head loss increasing profile during the filtration run length, by means of the Ergun equation. The goal was the determination of Ergun’s equation coefficients for granular material constituted of coarse sand and gravel. Examples of application of these mathematical modeling are also presented and discussed by the authors based on experimental data obtained in a double filtration pilot plant.

  1. Macroinvertebrate Community responses to gravel addition in a Southeastern regulated river

    Science.gov (United States)

    Ryan A. McManamay; Donald J. Orth; A. Charles. Dolloff

    2013-01-01

    Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread...

  2. Sand and gravel resources of Puerto Rico

    Science.gov (United States)

    Rodriguez, Rafael W.

    Many of Puerto Rico's beaches are eroding, and though rates of erosion vary, it is a major concern for the tourism and residential development industries. More than 85 percent of the population lives within 7 kilometers of the coast and they are heavily dependent on tourists that are attracted by the island's beaches and coral reefs. High-quality scientific data are needed to help formulate public policy regarding residential and commercial construction along the coast, beach replenishment, and future use of marine resources. Scientists have long recognized that the causes of coastal land loss are not limited to a relative rise in sea level, but can be manmade as well. For example, sediment supply to beaches especially along the north shore of Puerto Rico has been strongly affected by upstream river channeling, dam construction, various agricultural practices, paving and urbanization, as well as shallow-water oceanographic processes. The response to coastal erosion in Puerto Rico has been mostly crisis based leading to engineered solutions that have a negative effect on the coastal environment.

  3. Reconditioning contaminated gravel

    International Nuclear Information System (INIS)

    Walsh, H.; Bowers, J.S.; Cadwell, K.

    1995-02-01

    Lawrence Livermore National Laboratory (LLNL) has developed a portable screening system that will recondition radioactively contaminated gravel in the field. The separation technique employed by this system removes dirt, contaminated debris, and other fine particles from gravel. At LLNL, gravel is used in conjunction with the experimental testing of explosives to reduce shock wave propagation. The gravel surrounds the experimental device and buffers the energy generated from the explosion. During an explosion, some of the gravel is broken down into small particles and mixed with contaminants. Contaminants in the used gravel originate from metal sheathing and other parts comprising, the experimental device. These contaminants may consist of radionuclides and metals that are considered hazardous by the State of California when disposed. This paper describes the process that conveys contaminated material into the screener system, sprays the material with recycled water or other mild cleaning chemicals, and separates particles based on size. Particles greater than a specified size are discharged out of the screener separator and recycled back into use, thereby reducing the amount of mixed waste generated and minimizing the need for new gravel. The fines or silt are flushed out of the separator with the water and are removed from the water and consolidated into a drum with the use of a hydrocyclone separator and drum decant system. Because the water in the spray system is recycled, minimal makeup water is needed. The system monitors pH and total dissolved solids

  4. Abrasion-set limits on Himalayan gravel flux.

    Science.gov (United States)

    Dingle, Elizabeth H; Attal, Mikaël; Sinclair, Hugh D

    2017-04-26

    Rivers sourced in the Himalayan mountain range carry some of the largest sediment loads on the planet, yet coarse gravel in these rivers vanishes within approximately 10-40 kilometres on entering the Ganga Plain (the part of the North Indian River Plain containing the Ganges River). Understanding the fate of gravel is important for forecasting the response of rivers to large influxes of sediment triggered by earthquakes or storms. Rapid increase in gravel flux and subsequent channel bed aggradation (that is, sediment deposition by a river) following the 1999 Chi-Chi and 2008 Wenchuan earthquakes reduced channel capacity and increased flood inundation. Here we present an analysis of fan geometry, sediment grain size and lithology in the Ganga Basin. We find that the gravel fluxes from rivers draining the central Himalayan mountains, with upstream catchment areas ranging from about 350 to 50,000 square kilometres, are comparable. Our results show that abrasion of gravel during fluvial transport can explain this observation; most of the gravel sourced more than 100 kilometres upstream is converted into sand by the time it reaches the Ganga Plain. These findings indicate that earthquake-induced sediment pulses sourced from the Greater Himalayas, such as that following the 2015 Gorkha earthquake, are unlikely to drive increased gravel aggradation at the mountain front. Instead, we suggest that the sediment influx should result in an elevated sand flux, leading to distinct patterns of aggradation and flood risk in the densely populated, low-relief Ganga Plain.

  5. Coupling fine particle and bedload transport in gravel-bedded streams

    Science.gov (United States)

    Park, Jungsu; Hunt, James R.

    2017-09-01

    Fine particles in the silt- and clay-size range are important determinants of surface water quality. Since fine particle loading rates are not unique functions of stream discharge this limits the utility of the available models for water quality assessment. Data from 38 minimally developed watersheds within the United States Geological Survey stream gauging network in California, USA reveal three lines of evidence that fine particle release is coupled with bedload transport. First, there is a transition in fine particle loading rate as a function of discharge for gravel-bedded sediments that does not appear when the sediment bed is composed of sand, cobbles, boulders, or bedrock. Second, the discharge at the transition in the loading rate is correlated with the initiation of gravel mobilization. Third, high frequency particle concentration and discharge data are dominated by clockwise hysteresis where rising limb discharges generally have higher concentrations than falling limb discharges. These three observations across multiple watersheds lead to a conceptual model that fine particles accumulate within the sediment bed at discharges less than the transition and then the gravel bed fluidizes with fine particle release at discharges above the transition discharge. While these observations were individually recognized in the literature, this analysis provides a consistent conceptual model based on the coupling of fine particle dynamics with filtration at low discharges and gravel bed fluidization at higher discharges.

  6. Pebble breakage in gravel

    International Nuclear Information System (INIS)

    Tuitz, C.

    2012-01-01

    The spatial clustering of broken pebbles in gravel layers of a Miocene sedimentary succession was investigated. Field observations suggested that the occurrence of broken pebbles could be related with gravel hosted shear deformation bands, which were the result of extensional regional deformation. Several different methods were used in this work to elucidate these observations. These methods include basic field work, measurements of physical pebble and gravel properties and, the application of different numerical modelling schemes. In particular, the finite element method in 2D and the discrete element method in 2D and 3D were used in order to quantify mechanisms of pebble deformation. The main objective of this work was to identify potential mechanisms that control particle breakage in fluvial gravel, which could explain the clustered spatial distribution of broken pebbles. The results of 2D finite element stress analysis indicated that the breakage load of differently located and oriented diametrical loading axes on a pebble varies and, that the weakest loading configuration coincides with the smallest principal axis of the pebble. The 3D discrete element method was applied to study the contact load distribution on pebbles in gravel deposits and the influence of different degrees of particle imbrication and orientation. The results showed that an increase of the number of imbricated particles leads to a significant load transfer from the rim to the centre of the oblate sides of the ellipsoidal particles. The findings of these pebble-scale investigations provided the basis for outcropscale modelling, where simulated gravel layers were subjected to layer-parallel extension. These outcrop-scale models revealed the existence of a particle breakage enhancing mechanism that becomes active during early stages of shear band formation. The interaction of such shear bands with the less deformed host material results in particle stress concentrations and subsequently

  7. Estimates of hydraulic fracturing (Frac) sand production, consumption, and reserves in the United States

    Science.gov (United States)

    Bleiwas, Donald I.

    2015-01-01

    The practice of fracturing reservoir rock in the United States as a method to increase the flow of oil and gas from wells has a relatively long history and can be traced back to 1858 in Fredonia, New York, when a gas well situated in shale of the Marcellus Formation was successfully fractured using black powder as a blasting agent. Nearly all domestic hydraulic fracturing, often referred to as hydrofracking or fracking, is a process where fluids are injected under high pressure through perforations in the horizontal portion of a well casing in order to generate fractures in reservoir rock with low permeability (“tight”). Because the fractures are in contact with the well bore they can serve as pathways for the recovery of gas and oil. To prevent the fractures generated by the fracking process from closing or becoming obstructed with debris, material termed “proppant,” most commonly high-silica sand, is injected along with water-rich fluids to maintain or “prop” open the fractures. The first commercial application of fracking in the oil and gas industry took place in Oklahoma and Texas during the 1940s. In 1949, over 300 wells, mostly vertical, were fracked (ALL Consulting, LLC, 2012; McGee, 2012; Veil, 2012) and used silica sand as a proppant (Fracline, 2011). The resulting increase in well productivity demonstrated the significant potential that fracking might have for the oil and gas industry.

  8. Radiological characteristic of an area reclaimed by means of an ash-gravel power plant wastes

    International Nuclear Information System (INIS)

    Zak, A.; Biernacka, M.; Kusyk, M.; Mamont-Ciesla, K.; Florowska, K.

    2002-01-01

    A sand excavation after extraction of gravel and sand was filled with an ash-gravel mix. The mix was covered with shielding layers of clay and soil and grass was cultivated on it. Investigations of radiological characteristic such as: gamma radiation dose rate, radon concentration in soil air and radionuclide concentration in the ground were carried out in the both areas reclaimed one and in the vicinity of it. Radon exhalation coefficients were determined for uncovered ash-gravel mix layer, the shielding soil layer and for the ground in the vicinity. Analysis of the results revealed that the reclaimed area can be used for building development. (author)

  9. Filtration and transport of Bacillus subtilis spores and the F-RNA phage MS2 in a coarse alluvial gravel aquifer: implications in the estimation of setback distances.

    Science.gov (United States)

    Pang, Liping; Close, Murray; Goltz, Mark; Noonan, Mike; Sinton, Lester

    2005-04-01

    Filtration of Bacillus subtilis spores and the F-RNA phage MS2 (MS2) on a field scale in a coarse alluvial gravel aquifer was evaluated from the authors' previously published data. An advection-dispersion model that is coupled with first-order attachment kinetics was used in this study to interpret microbial concentration vs. time breakthrough curves (BTC) at sampling wells. Based on attachment rates (katt) that were determined by applying the model to the breakthrough data, filter factors (f) were calculated and compared with f values estimated from the slopes of log (cmax/co) vs. distance plots. These two independent approaches resulted in nearly identical filter factors, suggesting that both approaches are useful in determining reductions in microbial concentrations over transport distance. Applying the graphic approach to analyse spatial data, we have also estimated the f values for different aquifers using information provided by some other published field studies. The results show that values of f, in units of log (cmax/co) m(-1), are consistently in the order of 10(-2) for clean coarse gravel aquifers, 10(-3) for contaminated coarse gravel aquifers, and generally 10(-1) for sandy fine gravel aquifers and river and coastal sand aquifers. For each aquifer category, the f values for bacteriophages and bacteria are in the same order-of-magnitude. The f values estimated in this study indicate that for every one-log reduction in microbial concentration in groundwater, it requires a few tens of meters of travel in clean coarse gravel aquifers, but a few hundreds of meters in contaminated coarse gravel aquifers. In contrast, a one-log reduction generally only requires a few meters of travel in sandy fine gravel aquifers and sand aquifers. Considering the highest concentration in human effluent is in the order of 10(4) pfu/l for enteroviruses and 10(6) cfu/100 ml for faecal coliform bacteria, a 7-log reduction in microbial concentration would comply with the drinking

  10. Penggunaan Unit Slow Sand Filter, Ozon Generator dan Rapid Sand Filter Skala Rumah Tangga Untuk Meningkatkan Kualitas Air Sumur Dangkal Menjadi Air Layak Minum (Parameter Zat Organik dan Deterjen

    Directory of Open Access Journals (Sweden)

    Anindya Prawita Sari

    2014-09-01

    Full Text Available Air sumur merupakan air tanah yang sering kali digunakan masyarakat untuk aktivitas sehari-hari. Air sumur dengan kadar organik dan deterjen tinggi tidak layak dikonsumsi masyarakat karena dapat menyebabkan berbagai macam penyakit. Selain itu, adanya zat organik dan deterjen mempengaruhi warna dan bau air sumur sehingga tidak layak konsumsi. Slow sand filter merupakan unit pengolahan yang mampu meremoval zat organik pada air. Slow sand filter dan rapid sand filter tidak menggunakan bahan kimia dalam proses pengolahan sehingga lebih ekonomis dan efektif. Sedangkan ozon, efektif digunakan untuk meremoval zat organik yang ada dalam air dengan mengubah rantai zat organik menjadi lebih sederhana. Tujuan penelitian ini adalah untuk mengetahui keefektifan penggunaan slow sand filter, ozon generator dan rapid sand filter dalam menyisihkan beban deterjen dan zat organik pada air sumur. Hasil penelitian menunjukkan bahwa efisiensi removal pada unit slow sand filter untuk beban organik dan deterjen sebesar 57,6% dan 60,5 %, pada unit ozonasi sebesar 47,4% dan 17,5%, dan pada unit rapid sand filter sebesar 50,0% dan 50,9 %.

  11. Gravel roads management : volume 1, gravel roads management.

    Science.gov (United States)

    2010-10-01

    This report establishes procedures for managing dirt and gravel roads, with a primary focus on smaller agencies, such as Wyoming counties, that must manage their roads with very limited resources. The report strives, first, to guide and assist smalle...

  12. Gravel roads management : volume 2, gravel roads management : implementation guide.

    Science.gov (United States)

    2011-10-01

    This report establishes procedures for managing dirt and gravel roads, with a primary focus on smaller agencies, such as Wyoming counties, that must manage their roads with very limited resources. The report strives, first, to guide and assist smalle...

  13. Gravel roads management : volume 3, gravel roads management : programming guide.

    Science.gov (United States)

    2010-10-01

    This report establishes procedures for managing dirt and gravel roads, with a primary focus on smaller agencies, such as Wyoming counties, that must manage their roads with very limited resources. The report strives, first, to guide and assist smalle...

  14. Toxoplasmosis in sand cats (Felis margarita) and other animals in the Breeding Centre for Endangered Arabian Wildlife in the United Arab Emirates

    Science.gov (United States)

    The Sand cat (Felis margarita) is a small-sized felid occurring in the United Arab Emirates (UAE). The Sand cat captive breeding program at the Breeding Centre for Endangered Arabian Wildlife (BCEAW), Sharjah, UAE, has experienced high newborn mortality rates, and congenital toxoplasmosis was recent...

  15. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...

  16. The in-situ decontamination of sand and gravel aquifers by chemically enhanced solubilization of multiple-compound DNAPLs with surfactant solutions: Phase 1 -- Laboratory and pilot field-scale testing and Phase 2 -- Solubilization test and partitioning and interwell tracer tests. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-24

    Laboratory, numerical simulation, and field studies have been conducted to assess the potential use of micellar-surfactant solutions to solubilize chlorinated solvents contaminating sand and gravel aquifers. Ninety-nine surfactants were screened for their ability to solubilize trichloroethene (TCE), perchloroethylene (PCE), and carbon tetrachloride (CTET). The field test was conducted in the alluvial aquifer which is located 20 to 30 meters beneath a vapor degreasing operation at Paducah Gaseous Diffusion Plant. This aquifer has become contaminated with TCE due to leakage of perhaps 40,000 liters of TCE, which has generated a plume of dissolved TCE extending throughout an area of approximately 3 km{sup 2} in the aquifer. Most of the TCE is believed to be present in the overlying lacustrine deposits and in the aquifer itself as a dense, non-aqueous phase liquid, or DNAPL. The objective of the field test was to assess the efficacy of the surfactant for in situ TCE solubilization. Although the test demonstrated that sorbitan monooleate was unsuitable as a solubilizer in this aquifer, the single-well test was demonstrated to be a viable method for the in situ testing of surfactants or cosolvents prior to proceeding to full-scale remediation.

  17. The in-situ decontamination of sand and gravel aquifers by chemically enhanced solubilization of multiple-compound DNAPLs with surfactant solutions. Phase 1: Laboratory and pilot field-scale testing. Phase 2: Solubilization test and partitioning interwell tracer tests. Final report

    International Nuclear Information System (INIS)

    1997-01-01

    Laboratory, numerical simulation, and field studies have been conducted to assess the potential use of micellar-surfactant solutions to solubilize chlorinated solvents contaminating sand and gravel aquifers. Ninety-nine surfactants were screened for their ability to solubilize trichloroethene (TCE), perchloroethylene (PCE), and carbon tetrachloride (CTET). The field test was conducted in the alluvial aquifer which is located 20 to 30 meters beneath a vapor degreasing operation at Paducah Gaseous Diffusion Plant. This aquifer has become contaminated with TCE due to leakage of perhaps 40,000 liters of TCE, which has generated a plume of dissolved TCE extending throughout an area of approximately 3 km 2 in the aquifer. Most of the TCE is believed to be present in the overlying lacustrine deposits and in the aquifer itself as a dense, non-aqueous phase liquid, or DNAPL. The objective of the field test was to assess the efficacy of the surfactant for in situ TCE solubilization. Although the test demonstrated that sorbitan monooleate was unsuitable as a solubilizer in this aquifer, the single-well test was demonstrated to be a viable method for the in situ testing of surfactants or cosolvents prior to proceeding to full-scale remediation

  18. Performance of high-rate gravel-packed oil wells

    Energy Technology Data Exchange (ETDEWEB)

    Unneland, Trond

    2001-05-01

    Improved methods for the prediction, evaluation, and monitoring of performance in high-rate cased-hole gravel-packed oil wells are presented in this thesis. The ability to predict well performance prior to the gravel-pack operations, evaluate the results after the operation, and monitor well performance over time has been improved. This lifetime approach to performance analysis of gravel-packed oil wells contributes to increase oil production and field profitability. First, analytical models available for prediction of performance in gravel-packed oil wells are reviewed, with particular emphasis on high-velocity flow effects. From the analysis of field data from three North Sea oil fields, improved and calibrated cased-hole gravel-pack performance prediction models are presented. The recommended model is based on serial flow through formation sand and gravel in the perforation tunnels. In addition, new correlations for high-velocity flow in high-rate gravel-packed oil wells are introduced. Combined, this improves the performance prediction for gravel-packed oil wells, and specific areas can be targeted for optimized well design. Next, limitations in the current methods and alternative methods for evaluation and comparison of well performance are presented. The most widely used parameter, the skin factor, remains a convenient and important parameter. However, using the skin concept in direct comparisons between wells with different reservoir properties may result in misleading or even invalid conclusions. A discussion of the parameters affecting the skin value, with a clarification of limitations, is included. A methodology for evaluation and comparison of gravel-packed well performance is presented, and this includes the use of results from production logs and the use of effective perforation tunnel permeability as a parameter. This contributes to optimized operational procedures from well to well and from field to field. Finally, the data sources available for

  19. Gravel packing dual zones in one trip reduces offshore completion time

    International Nuclear Information System (INIS)

    Brannon, D.H.; Harrison, D.T.; van Sickle, E.W.

    1991-01-01

    A single trip, dual-zone gravel pack system was used to successfully gravel pack two wells on Green Canyon platform 52 A in the Gulf of Mexico. An average 56 hours was saved on each well, representing reductions of about 25% in completion time and 26% in completion cost per well. Time-sensitive costs had the largest impact on Green Canyon 52 A final well completion cost; therefore, new technology or more efficient operations were required to minimize completion time. One way to enhance project economics was to gravel pack two separate zones in one trip. In this paper, four objectives are addressed during development of a single trip tool to gravel pack the stacked zones of the Marquette project. These were time and cost reduction, removal of loss circulation material (LCM) prior to gravel packing, zone isolation during gravel packing and use of conventional gravel placement techniques. The design requirement that all LCM (salt and/or viscous polymer pills), perforation debris and formation sand be removed from the wellbore prior to gravel packing was accomplished by incorporating a washdown feature that allows circulation at the bottom of the gravel pack assembly prior to landing in the sump packer

  20. Efficiency of Cleanup of Ra-226 Contaminated Gravel Assayed by LSC and TL Dosimetry

    International Nuclear Information System (INIS)

    Mamoon, A.; Abulfaraj, W.H.; Kamal, S.M.; Sohsah, M.A.

    1999-01-01

    The present study concerns itself with decontamination of gravel that had been contaminated with Ra-226 from natural origins. Aqueous solutions of different compositions including water, and various concentrations of CaCl 2 and BaCl 2 were used to leach the contaminated gravel. The leaching experiments were carried out in glass columns. In some leaching experiments a sample of a common brand of sandy soil (fine sand with traces of silt )was placed below the gravel to test the binding capacity (sorption) of this soil for the leached Ra-226

  1. The spatial distribution of microfabric around gravel grains: indicator of till formation processes

    Science.gov (United States)

    KalväNs, Andis; Saks, Tomas

    2010-05-01

    Till micromorphology studies in thin sections is an established tool in the field of glacial geology. Often the thin sections are inspected only visually with help of mineralogical microscope. This can lead to subjective interpretation of observed structures. More objective method used in till micromorphology is measurement of apparent microfabric, usually seen as preferred orientation of elongated sand grains. In theses studies only small fraction of elongated sand grains often confined to small area of thin section usually are measured. We present a method for automated measurement of almost all elongated sand grains across the full area of the thin section. Apparently elongated sand grains are measured using simple image analysis tools, the data are processed in a way similar to regular till fabric data and visualised as a grid of rose diagrams. The method allows to draw statistical information about spatial variation of microfabric preferred orientation and fabric strength with resolution as fine as 1 mm. Late Weichselian tills from several sites in Western Latvia were studied and large variations in fabric strength and spatial distribution were observed in macroscopically similar till units. The observed types of microfabric spatial distributions include strong, monomodal and uniform distribution; weak and highly variable in small distances distribution; consistently bimodal distribution and domain-like pattern of preferred sand grain orientation. We suggest that the method can be readily used to identify the basic deformation and sedimentation processes active during the final stages of till formation. It is understood that the microfabric orientation will be significant affected by nearby large particles. The till is highly heterogonous sediment and the source of microfabric perturbations observed in thin section might lie outside the section plane. Therefore we suggest that microfabric distribution around visible sources of perturbation - gravel grains cut

  2. Impact of recycled gravel obtained from low or medium concrete grade on concrete properties

    Directory of Open Access Journals (Sweden)

    Yasser Abdelghany Fawzy

    2018-04-01

    Full Text Available This paper investigates the effect of recycled gravel obtained from low (Gl or medium (Gm concrete grade on fresh property of concrete (slump, mechanical properties (compressive-splitting tensile strength and mass transport properties (ISAT-sorptivity of concrete containing dolomite as a natural coarse aggregate. Concrete specimens were prepared with cement, water, sand and dolomite admixed with recycled gravel. The percentage of recycled gravel/dolomite was 0:100, 25:75, 50:50 and 75:25 at w/c = 0.50, 0.55 and 0.60. The effect of silica fume and bonding admixture at w/c = 0.55 on concrete properties were also considered. The results indicated that, increasing the percentage of recycled gravel/dolomite led to decreasing the slump. All mechanical properties of concrete discussed were inversely affected by increasing percentage of recycled gravel/dolomite from low and medium concrete. Adding 10% SF or bonding admixture increased the mechanical properties of concrete. Mass transport properties of concrete (ISAT-sorptivity were enhanced by decreasing the percentage of recycled gravel/dolomite. The optimum percentage of recycled gravel/dolomite = 25%. Keywords: Recycled gravel, Concrete, Silica fume, Compressive strength, Mass transport

  3. Recolonization of gravel habitats on Georges Bank (northwest Atlantic)

    Science.gov (United States)

    Collie, Jeremy S.; Hermsen, Jerome M.; Valentine, Page C.

    2009-09-01

    , gastropods) in the trays was 32 times that on the panels. Colonization of the tray gravel was more rapid for free-living species (many of which are prey for fish) than for structure-forming epifauna, though colonists of the latter species were present. The reduced success of structure-forming species in colonizing the tray gravel possibly is related to factors such as intermittent burial of the gravel by migrating sand and low survival of new recruits due to the presence of high numbers of scavengers on the gravel. These two factors might explain, to varying degree, the slow recolonization of gravel habitats by structure-forming species in Closed Area II of the northern part of Georges Bank.

  4. Recolonization of gravel habitats on Georges Bank (northwest Atlantic)

    Science.gov (United States)

    Collie, Jeremy S.; Hermsen, Jerome M.; Valentine, Page C.

    2009-01-01

    , gastropods) in the trays was 32 times that on the panels. Colonization of the tray gravel was more rapid for free-living species (many of which are prey for fish) than for structure-forming epifauna, though colonists of the latter species were present. The reduced success of structure-forming species in colonizing the tray gravel possibly is related to factors such as intermittent burial of the gravel by migrating sand and low survival of new recruits due to the presence of high numbers of scavengers on the gravel. These two factors might explain, to varying degree, the slow recolonization of gravel habitats by structure-forming species in Closed Area II of the northern part of Georges Bank. ?? 2009 Elsevier Ltd.

  5. Titanium mineral resources in heavy-mineral sands in the Atlantic coastal plain of the southeastern United States

    Science.gov (United States)

    Van Gosen, Bradley S.; Ellefsen, Karl J.

    2018-04-16

    This study examined titanium distribution in the Atlantic Coastal Plain of the southeastern United States; the titanium is found in heavy-mineral sands that include the minerals ilmenite (Fe2+TiO3), rutile (TiO2), or leucoxene (an alteration product of ilmenite). Deposits of heavy-mineral sands in ancient and modern coastal plains are a significant feedstock source for the titanium dioxide pigments industry. Currently, two heavy-mineral sands mining and processing operations are active in the southeast United States producing concentrates of ilmenite-leucoxene, rutile, and zircon. The results of this study indicate the potential for similar deposits in many areas of the Atlantic Coastal Plain.This study used the titanium analyses of 3,457 stream sediment samples that were analyzed as part of the U.S. Geological Survey’s National Geochemical Survey program. This data set was analyzed by an integrated spatial modeling technique known as Bayesian hierarchical modeling to map the regional-scale, spatial distribution of titanium concentrations. In particular, clusters of anomalous concentrations of titanium occur: (1) along the Fall Zone, from Virginia to Alabama, where metamorphic and igneous rocks of the Piedmont region contact younger sediments of the Coastal Plain; (2) a paleovalley near the South Carolina and North Carolina border; (3) the upper and middle Atlantic Coastal Plain of North Carolina; (4) the majority of the Atlantic Coastal Plain of Virginia; and (5) barrier islands and stretches of the modern shoreline from South Carolina to northeast Florida. The areas mapped by this study could help mining companies delimit areas for exploration.

  6. Gravel Roads: Maintenance and Design Manual

    Science.gov (United States)

    This manual was developed with a major emphasis on the maintenance of gravel roads, including some basic design elements. The purpose of the manual is to provide clear and helpful information for doing a better job of maintaining gravel roads.

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

    Science.gov (United States)

    Robinson, Marci M.; McBride, Randolph A.

    2008-01-01

    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.

  8. Mineral Resource Assessment of Marine Sand Resources in Cape- and Ridge-Associated Marine Sand Deposits in Three Tracts, New York and New Jersey, United States Atlantic Continental Shelf

    Science.gov (United States)

    Bliss, James D.; Williams, S. Jeffress; Arsenault, Matthew A.

    2009-01-01

    Demand is growing in the United States and worldwide for information about the geology of offshore continental shelf regions, the character of the seafloor, and sediments comprising the seafloor and subbottom. Interest in locating sand bodies or high quality deposits that have potential as sources for beach nourishment and ecosystem restoration is especially great in some regions of the country. The Atlantic coast, particularly New York and New Jersey, has been the focus of these studies for the past 40 years with widely varying results. This study is the first attempt at applying probability statistics to modeling Holocene-age cape-and ridge-associated sand deposits and thus focuses on distinct sand body morphology. This modeling technique may have application for other continental shelf regions that have similar geologic character and late Quaternary sea-level transgression history. An estimated volume of 3.9 billion m3 of marine sand resources is predicted in the cape-and ridge-associated marine sand deposits in three representative regions or tracts on the continental shelf offshore of New York and New Jersey. These estimates are taken from probabilistic distributions of sand resources and are produced using deposit models and Monte Carlo Simulation (MCS) techniques. The estimated sand resources presented here are for only three tracts as described below and for Holocene age sand resources contained in cape-and ridge-associated marine sand deposit types within this area. Other areas may qualify as tracts for this deposit type and other deposit types and geologic ages (for example, paleo-stream channels, blanket and outwash deposits, ebb-tide shoals, and lower sea level-stand deltas), which are present on the New Jersey and New York continental shelf area but are not delineated and modeled in this initial evaluation. Admittedly, only a portion of these probable sand resources will ultimately be available and suitable for production, dependent largely on

  9. Geologic-SURFICIAL62K-Sand and gravel pits

    Data.gov (United States)

    Vermont Center for Geographic Information — The GeologicSurficial_SURFICIAL data consists of surficial geologic features as digitized from the 1:62,500 15 minute series USGS quadrangle map sheets, compiled by...

  10. The Carolina Sandhills: Quaternary eolian sand sheets and dunes along the updip margin of the Atlantic Coastal Plain province, southeastern United States

    Science.gov (United States)

    Swezey, Christopher; Fitzwater, Bradley A.; Whittecar, G. Richard; Mahan, Shannon; Garrity, Christopher P.; Aleman Gonzalez, Wilma B.; Dobbs, Kerby M.

    2016-01-01

    The Carolina Sandhills is a physiographic region of the Atlantic Coastal Plain province in the southeastern United States. In Chesterfield County (South Carolina), the surficial sand of this region is the Pinehurst Formation, which is interpreted as eolian sand derived from the underlying Cretaceous Middendorf Formation. This sand has yielded three clusters of optically stimulated luminescence ages: (1) 75 to 37 thousand years ago (ka), coincident with growth of the Laurentide Ice Sheet; (2) 28 to 18 ka, coincident with the last glacial maximum (LGM); and (3) 12 to 6 ka, mostly coincident with the Younger Dryas through final collapse of the Laurentide Ice Sheet. Relict dune morphologies are consistent with winds from the west or northwest, coincident with modern and inferred LGM January wind directions. Sand sheets are more common than dunes because of effects of coarse grain size (mean range: 0.35–0.59 mm) and vegetation. The coarse grain size would have required LGM wind velocities of at least 4–6 m/sec, accounting for effects of colder air temperatures on eolian sand transport. The eolian interpretation of the Carolina Sandhills is consistent with other evidence for eolian activity in the southeastern United States during the last glaciation.

  11. Fabrication of gravel for concrete in brown-coal mining. The gravel works at Inden; Betonkiesherstellung im Braunkohlentagebau - Das Kieswerk Inden

    Energy Technology Data Exchange (ETDEWEB)

    Bertrams, H.J. [Rheinbraun AG, Abt. Tagebau- und Landschaftsplanung, Koeln (Germany)

    1995-01-01

    The brown-coal open-pit mine is operated by Rheinbraun AG, a Cologne-based company. The mining process offers the possibility to separate gravel and sand from the overburden for marketing, unless they are indispensable for reclaiming the open-pit mine. This combination of raw material production particularly prevents additional landscape consumption by separate gravel dredging and spares the population of an overproportionately densely populated region further inconveniences. Moreover, it helps to save resources. (orig./MSK) [Deutsch] Die Braunkohlengewinnung erfolgt durch die in Koeln ansaessige Rheinbraun AG in Tagebauen. Dabei ergibt sich die Moeglichkeit, im Abraum befindliche Kiese und Sande auszusortieren und dem Markt zuzufuehren, soweit sie nicht zwingend zur Wiedernutzbarmachung des Tagebaus verwendet werden muessen. Durch die Buendelung der Rohstoffgewinnung wird insbesondere der Landschaftsverbrauch durch gesonderte Abgrabungen ausserhalb des Tagebaus und damit verbundene Belastungen der Bevoelkerung in einer ueberdurchschnittlich dicht besiedelten Region verringert. Sie traegt ebenfalls zur Ressourcenschonung bei. (orig./MSK)

  12. Performance comparison of sand and fine sawdust vermifilters in treating concentrated grey water for urban poor.

    Science.gov (United States)

    Adugna, Amare T; Andrianisa, Harinaivo A; Konate, Yacouba; Ndiaye, Awa; Maiga, Amadou H

    2015-01-01

    A comparative investigation was conducted for 10 months with sand and fine sawdust vermifilters and a control unit to treat concentrated grey water generated from a poor urban household in Ouagadougou, Burkina Faso. Each of the filters was made up of cylindrical DN200-PVC pipes and filled with 10 cm of gravel at the bottom. On top of the gravel layer, filter 1 (fully sand, F1) was completed with 40 cm of sand and 10 cm of fine sawdust, filter 2 (partially sand, F2) with 20 cm of sand and 30 cm of fine sawdust, respectively, and filter 3 (fully sawdust, F3) and 4 (control, F4) with 50 cm of fine sawdust only. Two hundred Eudrilus eugeniae earthworms were inoculated in each of the vermifilters. The vermifiltration system was supplied with grey water four times per day at a hydraulic loading rate of 64 L/m(2)/day on a batch basis. The removal efficiencies of biological oxygen demand, total chemical oxygen demand, and dissolved chemical oxygen demand (dCOD) by the vermifilters were 25-30% higher than the control, but little differences were observed in terms of total suspended solids and coliform removal efficiencies. Though there was no significant difference in the performance of the three vermifilters (p > 0.05), except for dCOD removal efficiency, the lifespan of F2 and F3 was longer than that of F1. Therefore, fine sawdust can substitute sand as a filter medium in vermifilters.

  13. Spatial patterns in gravel habitats and communities in the central and eastern English Channel

    Science.gov (United States)

    Coggan, Roger; Barrio Froján, Christopher R. S.; Diesing, Markus; Aldridge, John

    2012-10-01

    The distribution of sediment type and benthic communities in the central and eastern English Channel is shown to be polarised around a distinctive local hydrodynamic feature. The seabed in the region includes an extensive area of gravel substrate which is both an important habitat for benthic marine fauna and a valuable source of material for the marine aggregate industry. Effective management of the area is predicated on an understanding of whether it represents a single homogeneous unit, or several different units that may need to be managed in different ways. The aim of this study was to provide information that would inform such management decisions. Spatial patterns in gravel habitats and communities were studied by investigating the physical environment through modelled and empirical data, and the distribution of infauna and epifauna along an east-west trending transect. A common spatial pattern was observed in both physical and biological parameters, but rather than indicating a simple longitudinal gradient, there was a distinct polarisation around a central feature, a bedload parting (BLP) zone situated between the Isle of Wight and Cotentin peninsula. Sediments and communities at the eastern and western ends of the transect were more similar to each other than to those in the middle. The strong hydrodynamic regime in the BLP area controls sediment distribution, transporting finer material, mainly sand, away from the mid transect area. The pattern in sand content of the substrate mirrors the magnitude of the potential bedload transport, which is complex in this region due to the interplay between the M2 and M4 tidal constituents and produced a series of erosional and depositional zones. The structure of benthic communities reflected the local substrate and hydrodynamic conditions, with sponges observed among the stable substrates and stronger currents that characterised the mid transect area, while infauna became more diverse towards the ends of the

  14. Macroinvertebrate community responses to gravel augmentation in a high-gradient, Southeastern regulated river

    Energy Technology Data Exchange (ETDEWEB)

    McManamay, Ryan A [ORNL; Orth, Dr. Donald J [Virginia Polytechnic Institute and State University; Dolloff, Dr. Charles A [United States Department of Agriculture (USDA), United States Forest Service (USFS) and Virginia Pol

    2013-01-01

    Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread practice, it is essential to evaluate the biotic response to restoration projects in order to improve the efficacy of future applications. The purpose of our study was to evaluate the response of the macroinvertebrate community to gravel addition in a high-gradient, regulated river in western North Carolina. We collected benthic macroinvertebrate samples from gravel-enhanced areas and unenhanced areas for 1 season before gravel addition, and for 4 seasons afterwards. Repeated measures multivariate analysis of variance indicated that the responses of macroinvertebrates to gravel addition were generally specific to individual taxa or particular functional feeding groups and did not lead to consistent patterns in overall family richness, diversity, density, or evenness. Non-metric multi-dimensional scaling showed that shifts in macroinvertebrate community composition were temporary and dependent upon site conditions and season. Correlations between macroinvertebrate response variables and substrate microhabitat variables existed with or without the inclusion of data from enhanced areas, which suggests that substrate-biotic relationships were present before gravel addition. A review of the current literature suggests that the responses of benthic macroinvertebrates to substrate restoration are inconsistent and dependent upon site conditions and the degree habitat improvement of pre-restoration site conditions.

  15. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  16. Shrinkage Properties of Cement Stabilized Gravel

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard

    2014-01-01

    Cement stabilized gravel is an attractive material in road construction because its strength prop-erties are accommodating the increasingly higher requirements to the bearing capacity of a base course. However, reflection cracking of cement stabilized gravel is a major concern. In this pa...

  17. Stabilization of gravel deposits using microorganisms

    NARCIS (Netherlands)

    Van der Star, W.R.L.; Van Wijngaarden, W.K.; Van Paassen, L.A.; Van Baalen, L.R.; Zwieten, G.

    2011-01-01

    One of the techniques used for the construction of underground infrastructure is horizontal directional drilling (HDD). This trenchless method is complicated when crossing gravel deposits as a borehole in coarse gravel tends to collapse, causing the drill pipe to get stuck or the failure of

  18. Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration

    Directory of Open Access Journals (Sweden)

    L. D. Sánchez

    2012-12-01

    Full Text Available This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF in a multi-stage filtration (MSF plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It strongly reduces the load of particulate material before the water enters in the slow sand filters (SSF and therewith avoids short filter runs and prevents early interruption in SSF operations. The removal efficiency of turbidity in the CF-UGF with coagulant was between 85 and 96%, whereas the average efficiency without coagulant dosing was 46% (range: 21–76%. Operating with coagulant also improves the removal efficiency for total coliforms, E-coli and HPC. No reduction was observed in the microbial activity of the SSF, no obstruction of the SSF bed was demonstrated and SSF runs were maintained between 50 and 70 days for a maximum head loss of 0.70 m. The most important advantage is the flexibility of the system to operate with and without coagulant according to the influent turbidity. It was only necessary for 20% of the time to operate with the coagulant. The CF-UGF unit represented 7% of total construction costs and the O&M cost for the use of coagulant represented only 0.3%.

  19. Hydrogeologic characteristics and water quality of a confined sand unit in the surficial aquifer system, Hunter Army Airfield, Chatham County, Georgia

    Science.gov (United States)

    Gonthier, Gerard

    2012-01-01

    An 80-foot-deep well (36Q397, U.S. Geological Survey site identification 320146081073701) was constructed at Hunter Army Airfield to assess the potential of using the surficial aquifer system as a water source to irrigate a ballfield complex. A 300-foot-deep test hole was drilled beneath the ballfield complex to characterize the lithology and water-bearing characteristics of sediments above the Upper Floridan aquifer. The test hole was then completed as well 36Q397 open to a 19-foot-thick shallow, confined sand unit contained within the surficial aquifer system. A single-well, 24-hour aquifer test was performed by pumping well 36Q397 at a rate of 50 gallons per minute during July 13-14, 2011, to characterize the hydrologic properties of the shallow, confined sand unit. Two pumping events prior to the aquifer test affected water levels. Drawdown during all three pumping events and residual drawdown during recovery periods were simulated using the Theis formula on multiple changes in discharge rate. Simulated drawdown and residual drawdown match well with measured drawdown and residual drawdown using values of horizontal hydraulic conductivity and specific storage, which are typical for a confined sand aquifer. Based on the hydrologic parameters used to match simulated drawdown and residual drawdown to measured drawdown and residual drawdown, the transmissivity of the sand was determined to be about 400 feet squared per day. The horizontal hydraulic conductivity of the sand was determined to be about 20 feet per day. Analysis of a water-quality sample indicated that the water is suitable for irrigation. Sample analysis indicated a calcium-carbonate type water having a total dissolved solids concentration of 39 milligrams per liter. Specific conductance and concentrations of all analyzed constituents were below those that would be a concern for irrigation, and were below primary and secondary water-quality criteria levels.

  20. Run-of-River Impoundments Can Remain Unfilled While Transporting Gravel Bedload: Numerical Modeling Results

    Science.gov (United States)

    Pearson, A.; Pizzuto, J. E.

    2015-12-01

    Previous work at run-of-river (ROR) dams in northern Delaware has shown that bedload supplied to ROR impoundments can be transported over the dam when impoundments remain unfilled. Transport is facilitated by high levels of sand in the impoundment that lowers the critical shear stresses for particle entrainment, and an inversely sloping sediment ramp connecting the impoundment bed (where the water depth is typically equal to the dam height) with the top of the dam (Pearson and Pizzuto, in press). We demonstrate with one-dimensional bed material transport modeling that bed material can move through impoundments and that equilibrium transport (i.e., a balance between supply to and export from the impoundment, with a constant bed elevation) is possible even when the bed elevation is below the top of the dam. Based on our field work and previous HEC-RAS modeling, we assess bed material transport capacity at the base of the sediment ramp (and ignore detailed processes carrying sediment up and ramp and over the dam). The hydraulics at the base of the ramp are computed using a weir equation, providing estimates of water depth, velocity, and friction, based on the discharge and sediment grain size distribution of the impoundment. Bedload transport rates are computed using the Wilcock-Crowe equation, and changes in the impoundment's bed elevation are determined by sediment continuity. Our results indicate that impoundments pass the gravel supplied from upstream with deep pools when gravel supply rate is low, gravel grain sizes are relatively small, sand supply is high, and discharge is high. Conversely, impoundments will tend to fill their pools when gravel supply rate is high, gravel grain sizes are relatively large, sand supply is low, and discharge is low. The rate of bedload supplied to an impoundment is the primary control on how fast equilibrium transport is reached, with discharge having almost no influence on the timing of equilibrium.

  1. Modeling potential impacts of the Garrison Diversion Unit project on Sand Lake and Arrowwood National Wildlife Refuges: a feasibility analysis

    Science.gov (United States)

    Hamilton, David B.; Auble, Gregor T.; Farmer, Adrian H.; Roelle, James E.

    1987-01-01

    The Garrison Diversion Unit (GDU) of the Pick-Sloan Missouri Basin program was authorized in 1965, with the purpose of diverting Missouri River water to the James River for irrigation, municipal and industrial water supply, fish and wildlife habitat, recreation, and flood control. The project was reauthorized in 1986, with the specification that comprehensive studies be conducted to address a variety of issues. One of these ongoing studies addresses potential impacts of GDU construction and operation on lands of the National Wildlife Refuge (NWR) system, including Arrowwood and Sand Lake Refuges (the Refuges) on the James River. A number of concerns at these Refuges have been identified; the primary concerns addressed in this report include increased winter return flows, which would limit control of rough fish; increased turbidity during project construction, which would decrease production of sago pondweed; and increased water level fluctuations in the late spring and early summer, which would destroy the nests of some over-water nesting birds. The facilitated workshop described in this report was conducted February 18-20, 1987, under the joint sponsorship of the U.S. Bureau of Reclamation, the U.S. Fish and Wildlife Service, and the North Dakota Game and Fish Department. The primary objectives of the workshop were to evaluate the feasibility of using simulation modeling techniques to estimate GDU impacts on Arrowwood and Sand Lake Refuges and to suggest enhancements to the James River Refuge monitoring program. The workshop was structured around the formulation of four submodels: a Hydrology and Water Quality submodel to simulate changes in Refuge pool elevations, turnover rates, and water quality parameters (e.g., total dissolved solids, turbidity, dissolved oxygen, nutrients, water temperature, pesticides) due to GDU construction and operation; a Vegetation submodel to simulate concomitant changes in wetland communities (e.g., sago pondweed, wet meadows, deep

  2. Sheet-gravel evidence for a late Holocene tsunami run-up on beach dunes, Great Barrier Island, New Zealand

    Science.gov (United States)

    Nichol, Scott L.; Lian, Olav B.; Carter, Charles H.

    2003-01-01

    A semi-continuous sheet of granule to cobble-size clasts forms a distinctive deposit on sand dunes located on a coastal barrier in Whangapoua Bay, Great Barrier Island, New Zealand. The gravel sheet extends from the toe of the foredune to 14.3 m above mean sea level and 200 m landward from the beach. Clasts are rounded to sub-rounded and comprise lithologies consistent with local bedrock. Terrestrial sources for the gravel are considered highly unlikely due to the isolation of the dunes from hillslopes and streams. The only source for the clasts is the nearshore to inner shelf of Whangapoua Bay, where gravel sediments have been previously documented. The mechanism for transport of the gravel is unlikely to be storm surge due to the elevation of the deposit; maximum-recorded storm surge on this coast is 0.8 m above mean high water spring tide. Aeolian processes are also discounted due to the size of clasts and the elevation at which they occur. Tsunami is therefore considered the most probable mechanism for gravel transport. Minimum run-up height of the tsunami was 14.3 m, based on maximum elevation of gravel deposits. Optical ages on dune sands beneath and covering the gravel allow age bracketing to 0-4.7 ka. Within this time frame, numerous documented regional seismic and volcanic events could have generated the tsunami, notably submarine volcanism along the southern Kermadec arc to the east-southeast of Great Barrier Island where large magnitude events are documented for the late Holocene. Radiocarbon ages on shell from Maori middens that appear to have been reworked by tsunami run-up constrain the age of this event to post ca. 1400 AD. Regardless of the precise age of this event, the well-preserved nature of the Whangapoua gravel deposit provides for an improved understanding of the high degree of spatial variability in tsunami run-up.

  3. Design and maintenance of subsurface gravel wetlands.

    Science.gov (United States)

    2015-02-01

    This report summarizes the University of New Hampshire Stormwater Center (UNHSC) evaluation of : a review of Subsurface Gravel Wetlands design and specifications used by the New Hampshire : Department of Transportation (NHDOT or Department). : Subsur...

  4. Origin, Extent, and Thickness of Quaternary Geologic Units in the Willamette Valley, Oregon

    Science.gov (United States)

    O'Connor, Jim E.; Sarna-Wojcicki, Andrei M.; Wozniak, Karl C.; Polette, Danial J.; Fleck, Robert J.

    2001-01-01

    Stratigraphic and chronologic information collected for Quaternary deposits in the Willamette Valley, Oregon, provides a revised stratigraphic framework that serves as a basis for a 1:250,000-scale map, as well as for thickness estimates of widespread Quaternary geologic units. We have mapped 11 separate Quaternary units that are differentiated on the basis of stratigraphic, topographic, pedogenic, and hydrogeologic properties. In summation, these units reflect four distinct episodes in the Quaternary geologic development of the Willamette Valley: 1) Fluvial sands and gravels that underlie terraces flanking lowland margins and tributary valleys were probably deposited between 2.5 and 0.5 million years ago. They are the oldest widespread surficial Quaternary deposits in the valley. Their present positions and preservation are undoubtedly due to postdepositional tectonic deformation - either by direct tectonic uplift of valley margins, or by regional tectonic controls on local base level. 2) Tertiary and Quaternary excavation or tectonic lowering of the Willamette Valley accommodated as much as 500 m (meters) of lacustrine and fluvial fill. Beneath the lowland floor, much of the upper 10 to 50 m of fill is Quaternary sand and gravel deposited by braided channel systems in subhorizontal sheets 2 to 10 m thick. These deposits grade to gravel fans 40 to 100 m thick where major Cascade Range rivers enter the valley and are traced farther upstream as much thinner valley trains of coarse gravel. The sand and gravel deposits have ages that range from greater than 420,000 to about 12,000 years old. A widely distributed layer of sand and gravel deposited at about 12 ka (kiloannum, thousands of years before the present) is looser and probably more permeable than older sand and gravel. Stratigraphic exposures and drillers' logs indicate that this late Pleistocene unit is mostly between 5 and 20 m thick where it has not been subsequently eroded by the Willamette River and its

  5. Morphometric and molecular analyses of the sand fly species Lutzomyia shannoni (Diptera: Psychodidae: Phlebotominae) collected from seven different geographical areas in the southeastern United States.

    Science.gov (United States)

    Florin, David A; Davies, Stephen J; Olsen, Cara; Lawyer, Phillip; Lipnick, Robert; Schultz, George; Rowton, Edgar; Wilkerson, Richard; Keep, Lisa

    2011-03-01

    A morphometric and molecular study of adult male and female Lutzomyia shannoni (Dyar 1929) collected at seven different locations within the southeastern United States was conducted to assess the degree of divergence between the grouped specimens from each location. The collection locations were as follows: Fort Bragg, NC; Fort Campbell, KY; Fort Rucker, AL; Ossabaw Island, GA; Patuxent National Wildlife Research Refuge, MD; Suwannee National Wildlife Refuge, FL; and Baton Rouge, LA. Forty males and forty females from each location were analyzed morphometrically from 54 and 49 character measurements, respectively. In addition, the molecular markers consisting of the partial cytochrome c oxidase subunit I (from 105 sand flies: 15 specimens/collection site) and the partial internal transcribed spacer 2 (from 42 sand flies: six specimens/collection site) were compared. Multivariate analyses indicate that the low degree of variation between the grouped specimens from each collection site prevents the separation of any collection site into an entity that could be interpreted as a distinct population. The molecular analyses were in concordance with the morphometric study as no collection location grouped into a separate population based on the two partial markers. The grouped specimens from each collection site appear to be within the normal variance of the species, indicating a single population in the southeast United States. It is recommended that additional character analyses of L. shannoni based on more molecular markers, behavioral, ecological, and physiological characteristics, be conducted before ruling out the possibility of populations or a cryptic species complex within the southeastern United States.

  6. Horizontal single-trip gravel pack and selective simulation system for deep water extended reach wells

    Energy Technology Data Exchange (ETDEWEB)

    Pineda, Francisco [BJ Services Company, Houston, TX (United States); Vilela, Alvaro; Montanha, Roberto; Acosta, Marco; Farias, Rodrigo [BJ Services do Brasil Ltda., Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Most of the reservoirs located in the deep water and ultra-deep water offshore South America are described as unconsolidated sandstone that require sand control on both producers and water injection wells. Horizontal Open Hole Gravel Pack completions are the preferred method of development. If completing heavy oil reservoirs, there is a necessity of longer horizontal open hole sections. Low fracture gradients may limit the length of gravel pack in the open hole section because of the pressure increase during the Beta wave proppant deposition phase. This system allows the gravel pack assembly to be installed and the gravel pack to be pumped during the alpha and beta wave deposition phases without the limitation of high pressures that could fracture the well. The benefits of the Horizontal Single-Trip Gravel Pack and Selective Stimulation System (HSTSSS) using the differential valve include the ability to complete longer horizontal intervals, valuable rig-time savings and, efficient mechanical diversion of the stimulation fluid. This paper outlines the application of the HSTSSS system using a differential valve to complete a horizontal well in offshore deep waters. The need for a differential valve is primarily in horizontal gravel packing operations when normal circulating rates and pressures around the open hole would exceed formation break down pressure. The valve is intended to be easily spaced out and run in the wash pipe. At a predetermined differential pressure the valve opens and the return flow path distance around the bottom of the tailpipe is shortened, thus reducing back pressure preventing filter cake damage without slowing the pump rate. In addition the said valve has to close to allow the selective stimulation to take place. Economic considerations along with completion efficiencies are especially important on deep water, subsea completions. The utilization of differential valves allows completion of extended-reach open hole wells and/or low fracture

  7. Seasonal movement change of sediments using RFID tracer monitoring in composite gravel beach, west coast of Korea

    Science.gov (United States)

    Han, M.; Yu, J.; Yang, D. Y.; Kim, J. W.

    2017-12-01

    The purpose of this study is to investigate seasonal movement patterns of gravel movements on the west coast of Korean peninsula. This study aims improve understanding of the process of coastal sediments movement and contribute to coastal erosion management. The study site is Taean Bangpo Beach, which is characterized by its macro tide and composite gravel beach (CGB). In this study, we carried out a radio frequency identifier (RFID) tracer movement monitoring experiment. Four hundred tracers, similar in size and shape to beach sediment, were inserted into the beach in February and December 2015. From the results, it was confirmed that generally, gravel moved southward in the winter and northward in the summer. It was also confirmed that the gravel moved long distances in the summer and winter, but much shorter distances in the spring. At the end of the results, it is confirmed that the tracer recovery rate in summer is lower than in winter. Bangpo Beach was influenced by strong wind and wave energy driven by the East Asian winter monsoon, and by normal tidal energy during the other seasons. It means that seasonal variation of gravel movement in the beach is attributed to the difference of seasonal energy conditions. In addition, it is interpreted that the sand at the intertidal zone cannot be removed in the summer when the wave energy is weak, causing the tracer to be buried. This study is expected to contribute to the study of composite gravel beach and coastal coarse sediment movement which have been lacking in research.

  8. Triaxial shear behavior of a cement-treated sand–gravel mixture

    Directory of Open Access Journals (Sweden)

    Younes Amini

    2014-10-01

    Full Text Available A number of parameters, e.g. cement content, cement type, relative density, and grain size distribution, can influence the mechanical behaviors of cemented soils. In the present study, a series of conventional triaxial compression tests were conducted on a cemented poorly graded sand–gravel mixture containing 30% gravel and 70% sand in both consolidated drained and undrained conditions. Portland cement used as the cementing agent was added to the soil at 0%, 1%, 2%, and 3% (dry weight of sand–gravel mixture. Samples were prepared at 70% relative density and tested at confining pressures of 50 kPa, 100 kPa, and 150 kPa. Comparison of the results with other studies on well graded gravely sands indicated more dilation or negative pore pressure in poorly graded samples. Undrained failure envelopes determined using zero Skempton's pore pressure coefficient (A¯=0 criterion were consistent with the drained ones. Energy absorption potential was higher in drained condition than undrained condition, suggesting that more energy was required to induce deformation in cemented soil under drained state. Energy absorption increased with increase in cement content under both drained and undrained conditions.

  9. Design, Construction and Testing of a Dry Sand Sieving Machine ...

    African Journals Online (AJOL)

    This paper reports on the design, construction and Testing of a dry sand sieving machine. The sample to be sieved is uniformly graded. The coefficient of uniformity is 1.11, thus the machine design does not sieve larger particles such as gravel. The slip calculated is 36% which enabled the proper configuration of the V-belt.

  10. Incipient motion of gravel and coal beds

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    2. 1Department of Civil Engineering, Indian Institute of Technology, ... the particle size distribution curve following the relationship by Christensen .... where f = friction factor, ρ = mass density of fluid, and V = mean velocity of flow. .... for the incipient motion of gravel and coal beds have been represented by simple empirical.

  11. Optimizing the use of natural gravel Brantas river as normal concrete mixed with quality fc = 19.3 Mpa

    Science.gov (United States)

    Limantara, A. D.; Widodo, A.; Winarto, S.; Krisnawati, L. D.; Mudjanarko, S. W.

    2018-04-01

    The use of natural gravel (rivers) as concrete mixtures is rarely encountered after days of demands for a higher strength of concrete. Moreover, today people have found High-Performance Concrete which, when viewed from the rough aggregate consisted mostly of broken stone, although the fine grain material still used natural sand. Is it possible that a mixture of concrete using natural gravel as a coarse aggregate is capable of producing concrete with compressive strength equivalent to a concrete mixture using crushed stone? To obtain information on this, a series of tests on concrete mixes with crude aggregates of Kalitelu Crusher, Gondang, Tulungagung and natural stone (river gravel) from the Brantas River, Ngujang, Tulungagung in the Materials Testing Laboratory Tugu Dam Construction Project, Kab. Trenggalek. From concrete strength test results using coarse material obtained value 19.47 Mpa, while the compressive strength of concrete with a mixture of crushed stone obtained the value of 21.12 Mpa.

  12. Viscoelastic gravel-pack carrier fluid

    International Nuclear Information System (INIS)

    Nehmer, W.L.

    1988-01-01

    The ability of a fluid to flow adequately into the formation during gravel-pack treatments is critical to achieving a good pack. Recent studies have indicated ''fish-eyes'' and/or ''microgels'' present in many polymer gelled carrier fluids will plug pore throats, leading to impaired leakoff and causing formation damage. Intensive manipulation of the polymer gelled fluid using shear and filter devices will help remove the particles, but it adds to the cost of the treatment in terms of equipment and manpower. Excessive shear will degrade the polymer leading to poor gravel suspension, while too little shear will cause filtration problems. A gelled carried fluid using a viscoelastic surfactant system has been found to leak off very efficiently to the formation, and cause no formation damage, without the use of shear/filter devices. Viscoelastic surfactant-base gelled fluids develop viscosity because of the association of surfactant moloecules into large rod-shaped aggregates. There is no hydration of polymer involved, so fish-eyes and microgels will not be formed in the viscoelastic fluid. A surfactant-base system having a yield point allows the gravel carrying properties to be much better than fluids gelled with conventional polymer systems (hydroxyethylcellulose [HEC]). For example, a gravel carried fluid gelled with 80 lb HEC/1,000 gal has a viscosity of about 400 cp at 170 sec/sup -1/; a viscoelastic surfactant-base system having only one-half the viscosity still flows into cores about four times more efficiently than the HEC-base fluid. The rheology, leakoff, formation damage and mixing properties of a viscoelastic, surfactant-base, gravel-pack carrier fluid are discussed

  13. Decontamination process development for gravels contaminated with uranium

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gye Nam; Park, Uk Ryang; Kim, Seung Su; Kim, Won Suk; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    It is impossible to scrub gravels in a washing tank, because gravels sinks to the bottom of the washing tank. In addition, when electrokinetic decontamination technology is applied to gravels larger than 10 cm, the removal efficiency of uranium from the gravels is reduced, because electro-osmotic flux at the surface of the gravel in electrokinetic cell reduces owing to a reduction of the particle surface area attributable to large-sized gravel. The volume ratio of gravel larger than10 cm in total volume of the soil in KAERI was about 20%. Therefore, it is necessary to study the decontamination process of gravels contaminated with radionuclides. The optimum number of washings for contaminated gravels is considered to be two. In addition, the removal efficiency of contaminated gravel was not related to its weight. For an electrokinetic-electrodialytic decontamination period of 5 days, 10 days, 15 days, and 20 days, {sup 238}U in gravel was removed by about 42%, 64%, 74%, and 80%, respectively. The more the decontamination time elapsed, the greater the reduction of the removal efficiency ratio of {sup 238}U. The decontamination process for gravels was generated on the basis of the results of washing and electrokinetic electrodialtic experiments.

  14. Variability of hyporheic exchange in an experimental gravel bed

    NARCIS (Netherlands)

    Perk, M. van der; Petticrew, E.L.; Owens, P.N.

    2011-01-01

    A series of tracer experiments in a large outdoor flume were conducted to examine the variability of hyporheic exchange in gravel bed sediments. An 18 m long section of a 2 m wide flume was filled with a 30 cm thick gravel layer with a porosity of 0.39. The gravel of the 17 cm top layer was

  15. MORPHOMETRIC CHARACTERIZATION OF THE SAND FRACTION IN A SAND GRAIN IMAGE CAPTURE SYSTEM1

    Directory of Open Access Journals (Sweden)

    Lucimar Arruda Viana

    Full Text Available ABSTRACT Morphology studies assume significant importance in analysis of phenomena of granular systems packaging, in particular with a view to the use of the technique of soil stabilization named particle size correction in forest roads. In this context, this study aimed to develop and operationalize a Sand Grain Image Capture System and, hereby, determine the morphological indices of the sand fractions of two sandy soils called João Pinheiro (JP and Cachoeira da Prata (CP. Soil samples, air-dried, were sieved (2.0 mm nominal mesh size for removal of gravels. The materials that passed through the sieve were subjected to dispersion, washing in 0.053 mm nominal mesh size sieve, removal of organic matter and iron oxides to obtain the clean sand fractions. Subsequently, each soil sample was sieved for separation into twelve classes, between the diameters of 0.149 mm and 1.190 mm, using a Rotap shaker. Next, tests were carried out to characterize the morphometric attributes of the twelve classes of sand fractions of the soils studied. For validation of the performance of the Sand Grain Image Capture System, the results were compared to those obtained using a standard procedure for image analysis. The analysis of the results led to the following conclusions: (i the sand fraction of the JP soil presented higher values for the morphometric indices roundness, elongation and compactness compared to sand fraction of the CP soil; and (ii the Sand Grain Image Capture System worked properly, with practicality.

  16. Water and chemical budgets of gravel pit lakes : Case studies of fluvial gravel pit lakes along the Meuse River (The Netherlands) and coastal gravel pit lakes along the Adriatic Sea (Ravenna, Italy)

    NARCIS (Netherlands)

    Mollema, P.N.

    2016-01-01

    Gravel pit lakes form when gravel is excavated from below the water table of a phreatic or shallow confined aquifer. Typically many of these lakes are concentrated along naturally occurring sedimentary gravel deposits in areas where gravel is needed for construction. Most gravel pit lakes are

  17. Advanced Reservoir Characterization and Development through High-Resolution 3C3D Seismic and Horizontal Drilling: Eva South Marrow Sand Unit, Texas County, Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler,David M.; Miller, William A.; Wilson, Travis C.

    2002-03-11

    The Eva South Morrow Sand Unit is located in western Texas County, Oklahoma. The field produces from an upper Morrow sandstone, termed the Eva sandstone, deposited in a transgressive valley-fill sequence. The field is defined as a combination structural stratigraphic trap; the reservoir lies in a convex up -dip bend in the valley and is truncated on the west side by the Teepee Creek fault. Although the field has been a successful waterflood since 1993, reservoir heterogeneity and compartmentalization has impeded overall sweep efficiency. A 4.25 square mile high-resolution, three component three-dimensional (3C3D) seismic survey was acquired in order to improve reservoir characterization and pinpoint the optimal location of a new horizontal producing well, the ESU 13-H.

  18. Alternatives to conventional gravel wearing courses on low volume rural roads: Phase 1

    CSIR Research Space (South Africa)

    Paige-Green, P

    2003-01-01

    Full Text Available Adviser Abstract Gundo Lashu, the ‘Labour Intensive Rural Roads Maintenance Programme’ that is currently being implemented in Limpopo Province, South Africa has set out to train 24 emerging contractors in rehabilitation of rural gravel roads. All.... The proposal is to treat the in situ materials and sand with a diluted emulsion and a nominal cement application (to assist with breaking of the emulsion) and surface the road with an Otta seal. The aggregate for the Otta seal can be obtained form...

  19. Effect of gravel on hydraulic conductivity of compacted soil liners

    International Nuclear Information System (INIS)

    Shelley, T.L.; Daniel, D.E.

    1993-01-01

    How much gravel should be allowed in low-hydraulic-conductivity, compacted soil liners? To address this question, two clayey soils are uniformly mixed with varying percentages of gravel that, by itself, has a hydraulic conductivity of 170 cm/s. Soil/gravel mixtures are compacted and then permeated. Hydraulic conductivity of the compacted gravel/soil mixtures is less than 1 x 10 -7 cm/s for gravel contents as high as 50-60%. For gravel contents ≤ 60%, gravel content is not important: all test specimens have a low hydraulic conductivity. For gravel contents > 50-60%, the clayey soils does not fill voids between gravel particles, and high hydraulic conductivity results. The water content of the nongravel fraction is found to be a useful indicator of proper moisture conditions during compaction. From these experiments in which molding water content and compactive energy are carefully controlled, and gravel is uniformly mixed with the soil, it is concluded that the maximum allowable gravel content is approximately 50%

  20. Sand consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Spain, H H

    1965-01-21

    In a sand consolidation method in which there is injected a mixture of resin-forming liquids comprising an aryl-hydroxy low molecular weight compound, a water- soluble aldehyde, and a catalyst, an improvement is claimed which comprises diluting the resin-forming liquids with a diluent and with water so that the yield of the resin is sufficient to consolidate the sand particles with the minimum desirable pressure. The diluent may be mutually soluble in water and in the resin-forming liquids, and does not affect the setting time of the polymer. The aldehyde and the aryl-hydroxy compound may be in ratio of 5:1, and the diluent, methyl alcohol, is present in a ratio of 2:1 with reference to the water.

  1. Channel dynamics and geomorphic resilience in an ephemeral Mediterranean river affected by gravel mining

    Science.gov (United States)

    Calle, Mikel; Alho, Petteri; Benito, Gerardo

    2017-05-01

    Gravel mining has been a widespread activity in ephemeral rivers worldwide whose long-lasting hydrogeomorphological impacts preclude effective implementation of water and environmental policies. This paper presents a GIS-based method for temporal assessment of morphosedimentary changes in relation to in-channel gravel mining in a typical ephemeral Mediterranean stream, namely the Rambla de la Viuda (eastern Spain). The aims of this work were to identify morphosedimentary changes and responses to human activities and floods, quantify river degradations and analyze factors favoring fluvial recovery for further applications in other rivers. Aerial photographs and LiDAR topography data were studied to analyze geomorphic evolution over the past 70 years along a 7.5-km reach of an ephemeral gravel stream that has been mined intensively since the 1970s. To evaluate changes in the riverbed, we mapped comparable units applying morphological, hydraulic, and stability (based on vegetation density and elevation) criteria to 13 sets of aerial photographs taken from 1946 to 2012. A detailed spatiotemporal analysis of comparable units revealed a 50% reduction in the active section and a 20% increase in stable areas, compared to the conditions observed prior to gravel mining. Instream mining was first observed in 1976 aerial photograph covering already up to 50% of the 1956 riverbed area. River degradation since then was quantified by means of a LiDAR DTM and RTK-GPS measurements, which revealed a 3.5-m incision that had started simultaneously with gravel mining. Climate and land use changes were present but the effects were completely masked by changes produced by instream gravel mining. Therefore, river incision/degradation was triggered by scarcity of sediment and lack of longitudinal sedimentary connection, creating an unbalanced river system that is still adjusting to the present hydrosedimentary conditions.

  2. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    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

  3. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  4. Alberta oil sands royalty regime

    International Nuclear Information System (INIS)

    Asgarpour, S.

    2004-01-01

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  5. Shifting Sands in the United Arab Emirates: Effecting Conceptual Change for Creativity in Early Childhood Teacher Education

    Science.gov (United States)

    Baker, Fiona S.

    2013-01-01

    This study examines the effectiveness of a four-stage conceptual change approach to creativity development in teacher education in the Emirate of Dubai, the United Arab Emirates. The participants were 32 student teachers studying at undergraduate level at an all-female university. The study examined participant preconceptions of creativity and how…

  6. Development of a submerged gravel scrubber for containment venting applications: summary

    International Nuclear Information System (INIS)

    Hilliard, R.K.; McCormack, J.D.; Postma, A.K.

    1981-01-01

    Although hypothetical core disruptive accidents (HCDAs) are not design basis accidents for breeder reactor plants, extensive assessments of HCDA consequences have been made and design features for providing margins beyond the design base have been considered for future fast reactor plants. One feature proposed for increasing the safety margin is a containment vent and/or purge system which would mitigate the challenge to containment integrity resulting from excessive temperature and pressure or excessive hydrogen. A cleanup system would be required for removal of vented aerosols and condensible vapors to mitigate radiological consequences to the environment. A study is in progress at HEDL to select and develop a suitable air cleaning system for use in potential breeder reactor containment venting applications. A concept was conceived whereby the passiveness and high loading capacity of a water pool scrubber was combined with the high efficiency of a sand and gravel bed. It was termed a Submerged Gravel Scrubber (SGS). A schematic drawing of the concept is shown. The SGS consists of a bed of gravel (or other packing) submerged in a pool of water

  7. Paleo-Environment and C-14 Dating: The Key to the Depositional Age of the Tha Chang and Related Sand Pits, Northeastern Thailand

    Science.gov (United States)

    Putthapiban, P.; Zolensky, M.; Jull, T.; Demartino, M.; Salyapongse, S.

    2012-01-01

    Tha Chang sand pits, Nakhon Ratchasima Province and many other sand pits in the area adjacent to the Mun River are characterized by their fluviatile environment in association with mass wasting deposits, along the paleo-river channel and the flood plain of the Mun River. Sediments of these deposits are characterized by clasts of various rock types especially the resistant ones with frequent big tree trunks, logs and wood fragments in different sizes and various stages of transformation from moldering stage to lignification and petrification. Widespread pyritization of the lower horizon suggests strongly reducing environment during burial. The Tha Chang deposits have been received much attention from geoscientists especially paleontologist communities, as they contain fragments of some distinct vertebrate species such as Stegadon sp., hominoid primate, rhinoceros Aceratherium and others. Based on the associated mammal fauna and hominoid fossils, the late Miocene ( 9 - 6 Ma) was given for the time of deposition of this sand and gravel unit. Some other reports believed that sediments and materials of these sand and gravel quarries (pits) were deposited by high-energy flood pulses contemporaneous with the tektites forming event during mid-Pleistocene at c. 0.8 Ma. Interpretation from Palynostratigraphical study suggested that the lower horizon of Tha Chang sand pit was deposited during Pliocene/Pleistocene period and the upper horizons are Pleistoncene/Holocene. It is crystal clear that all the fluviatile sediments including tektites and almost all fossil fragments being deposited in these sand pits were, likely a multiple times reworked materials. Only some old bamboo trees, some old crowling trees and fossils grasses observed on the old river bank are considered in situ. C-14 dating of 5 old wood specimens from Tha Chang Sand Pits, 15 old wood specimens from Chumpuang Sand Pits and one sample of old pottery from a Chumpuang Sand Pit were carried out in the NSF

  8. Mineral sands

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This paper presents an outlook of the Australian mineral sand industry and covers the major operators. It is shown that conscious of an environmentally minded public, the Australian miners have led the way in the rehabilitation of mined areas. Moreover the advanced ceramic industry is generating exciting new perspectives for zircon producers and there is a noticeable growth in the electronic market for rare earths, but in long term the success may depend as much on environmental management and communication skills as on mining and processing skills

  9. Effect of substrate size on sympatric sand darter benthic habitat preferences

    Science.gov (United States)

    Thompson, Patricia A.; Welsh, Stuart A.; Rizzo, Austin A.; Smith, Dustin M.

    2017-01-01

    The western sand darter, Ammocrypta clara, and the eastern sand darter, A. pellucida, are sand-dwelling fishes that have undergone range-wide population declines, presumably owing to habitat loss. Habitat use studies have been conducted for the eastern sand darter, but literature on the western sand darter remains sparse. To evaluate substrate selection and preference, western and eastern sand darters were collected from the Elk River, West Virginia, one of the few remaining rivers where both species occur sympatrically. In the laboratory, individuals were given the choice to bury into five equally available and randomly positioned substrates ranging from fine sand to granule gravel (0.12–4.0 mm). The western sand darter selected for coarse and medium sand, while the eastern sand darter was more of a generalist selecting for fine, medium, and coarse sand. Substrate selection was significantly different (p = 0.02) between species in the same environment, where the western sand darter preferred coarser substrate more often compared to the eastern sand darter. Habitat degradation is often a limiting factor for many species of rare freshwater fish, and results from this study suggest that western and eastern sand darters may respond differently to variations in benthic substrate composition.

  10. Experimental Study of Irregular Waves on a Gravel Beach

    Science.gov (United States)

    Hu, Nai-Ren; Wu, Yun-Ta; Hwung, Hwung-Hweng; Yang, Ray-Yeng

    2017-04-01

    In the east coast of Taiwan, the sort grain size more belongs to cobble or gravel, which is physically distinct compared to the sandy beach in the west coast of Taiwan. Although gravel beaches can dissipate more of wave energy, gravel beaches were eroded and coastal road were damaged especially during typhoons. The purpose of this study is to investigate the geomorphological response of gravel beach due to irregular waves. This experiment was carry out in a 21m long, 50 cm wide, 70 cm high wave tank at Tainan Hydraulics Laboratory, National Cheng-Kung University, Taiwan. To simulate of the geometry in the east coast of Taiwan, a physical model with 1/36 scale-down was used, in which the seawall was 10cm built upon a 1:10 slope and gravel grains with D50 being 3.87 mm was nourished in front of the seawall. In terms of typhoon-scale wave condition, irregular waves with scale-down conditions were generated for 600 s for each scenarios and, three different water levels with respect to the gravel beach are designed. Application of laser combined with image processing to produce 3D topographic map, the erosion zone and accretion zone would be found. The resulting morphological change of gravel beach will be measured using an integrated laser and image processing tool to have 3D topographic maps. It is expected to have more understanding about under what conditions the gravel coasts suffer the least damage. In particular, the relation between erosion rates of gravel beach, the angle of gravel slope and the length of the plane on the gravel slope will be achieved

  11. Design of Screens for Sand Control of Wells

    Directory of Open Access Journals (Sweden)

    Ján Pinka

    2006-04-01

    Full Text Available Drilling, completion, production, and reservoir engineers, supervisors, foremen, superintendents, service company personnel, technologists and anyone involved with recommending, selecting, designing or on-site performance of well completions or workovers where sand production is, or may become, a serious problem will benefit from this course. Less sand influx can be expected in a horizontal well than in a vertical well. If horizontal holes in weak formation sands can be successfully gravel packed, the result could be significantly higher well productivity than with a liner, screen or pre-packed screen alone. The article covers innovative screens for sand control used in oil and gas industry from the world leaders in total completion. The type of screen (wire wrapped, reinforced, pre-packed, ect. should also be chosen with due consideration to running-in condition (curve radius, compression when the screens are pushed along the drain hole, etc..

  12. Discrete Element Modeling of the Mobilization of Coarse Gravel Beds by Finer Gravel Particles

    Science.gov (United States)

    Hill, K. M.; Tan, D.

    2012-12-01

    Recent research has shown that the addition of fine gravel particles to a coarse bed will mobilize the coarser bed, and that the effect is sufficiently strong that a pulse of fine gravel particles can mobilize an impacted coarser bed. Recent flume experiments have demonstrated that the degree of bed mobilization by finer particles is primarily dependent on the particle size ratio of the coarse and fine particles, rather than absolute size of either particle, provided both particles are sufficiently large. However, the mechanism behind the mobilization is not understood. It has previously been proposed that the mechanism is driven by a combination of geometric effects and hydraulic effects. For example, it has been argued that smaller particles fill in gaps along the bed, resulting in a smoother bed over which the larger particles are less likely to be disentrained and a reduced near-bed flow velocity and subsequent increased drag on protruding particles. Altered near-bed turbulence has also been cited as playing an important role. We perform simulations using the discrete element method with one-way fluid-solid coupling to conduct simulations of mobilization of a gravel bed by fine gravel particles. By independently and artificially controlling average and fluctuating velocity profiles, we systematically investigate the relative role that may be played by particle-particle interactions, average near-bed velocity profiles, and near-bed turbulence statistics. The simulations indicate that the relative importance of these mechanisms changes with the degree of mobilization of the bed. For higher bed mobility similar to bed sheets, particle-particle interactions, plays a significant role in an apparent rheology in the bed sheets, not unlike that observed in a dense granular flow of particles of different sizes. For conditions closer to a critical shear stress for bedload transport, the near-bed velocity profiles and turbulence statistics become increasingly important.

  13. MANUAL. Fly ash in civil engineering, Gravel roads; HANDBOK. Flygaska i mark- och vaegbyggnad, Grusvaegar

    Energy Technology Data Exchange (ETDEWEB)

    Munde, Hanna; Svedberg, Bo; Macsik, Josef; Maijala, Aino; Lahtinen, Pentti; Ekdahl, Peter; Neren, Jens [Vattenfall AB, Stockholm (Sweden). Vaerme Norden

    2006-01-15

    Fly ash based on biofuels or coal has been used as construction material for a long time in roads and other civil engineering applications. Some example, where it has been used in roadbase and subbase of gravel roads, are in the counties of Uppsala, Soedermanland, Vaestmanland and in Finland. The use of fly ash has contributed to good function for example as bearing capacity, thaw and frost capacity and good durability. This has also reduced costs for maintenance. The objective of this project was to develop a manual to provide a base for contemporary use of fly ash in road constructions. In the manual experience from studies, field tests and regulations has been compiled. The manual handles fly ash as base for products to be used in base and subbase in gravel roads. Future user of the guidelines are mainly consultant engineers and contractors. However the aim of the manual is to also support road administrators, environmental authorities and industry. The project has been carried out parallel to another ongoing national project titled 'Guidelines, Use of alternative materials in civil engineering'. The objective of that project is to establish a base for handling of alternative materials in Sweden. Fly ash in gravel roads are mainly used in two typical applications, one without any additive in a single layer and one with fly ash mixed with gravel. The use of flyash provides functional properties such as increased stiffness, stability and enhanced frost and thaw capacity for the road construction in total. Furthermore the products based on fly ash will have low permeability and good frost and thaw durability. These properties are for example related to fly ash quality, design and construction and are in general expected to be better than for traditional constructions using, for example, sand or gravel. The properties can be enhanced further by using binders such as cement and Merit. Fly ash should always be used above the ground water table with

  14. Bed topography and sand transport responses to a step change in discharge and water depth

    Science.gov (United States)

    Ephemeral streams with sand and gravel beds may inherit bed topography caused by previous flow events, resulting in bed topography that is not in equilibrium with flow conditions, complicating the modeling of flow and sediment transport. Major flow events, resulting from rainfall with high intensity...

  15. Ecological significance of riverine gravel bars in regulated river reaches below dams

    Science.gov (United States)

    Ock, G.; Takemon, Y.; Sumi, T.; Kondolf, G. M.

    2012-12-01

    A gravel bar has been recognized as ecologically significant in that they provide simplified habitat with topographical, hydrological and thermo-chemical diversity, while enhancing material exchanges as interfaces laterally between aquatic and terrestrial habitats, and vertically between surface and subsurface waters. During past several decades, regulated rivers below dams have been loss of a number of the geomorphological features due to sediment starvation by upstream dams, accompanied by a subsequent degradation of their ecological functions. Despite a growing concern for gravel bar management recognizing its importance in recovering riverine ecosystem services, the ecological roles of gravel bars have not been assessed enough from the empirical perspectives of habitat diversity and organic matter interactions. In this study, we investigate the 'natural filtering effects' for reducing lentic plankton and contaminants associated with self-purification, and 'physicochemical habitat complexity' of gravel bars, focusing on reach-scaled gravel bars in rivers located in three different countries; First is the Uji River in central Japan, where there has been a loss of gravel bars in the downstream reaches since an upstream dam was constructed in 1965; second is the Tagliamento River in northeast Italy, which shows morphologically intact braided bar channels by natural flooding events and sediment supply; third is the Trinity River in the United States (located in northern California), the site of ongoing restoration efforts for creating new gravel bars through gravel augmentation and channel rehabilitation activities. We traced the downstream changes in particulate organic matter (POM) trophic sources (composed of allochthonous terrestrial inputs, autochthonous instream production and lentic plankton from dam outflows) in order to evaluate the roles of the geomorphological features in tailwater ecosystem food-resources shifting. We calculated suspended POM

  16. The Development of Treatment Process Technology for Radioactive Gravel

    Energy Technology Data Exchange (ETDEWEB)

    Shon, Dong Bin; Kim, Gye Nam; Park, Hye Min; Kim, Ki Hong; Kim, Wan Suk; Lee, Kun Woo; Lee, Ki Won; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    The soil washing method holds great promise for the decontamination of contaminated soil as it is very efficient at removal and is time-effective for a great deal of contaminated soils. In addition, this method compensates for a weak point in that is generates a great deal of uranium-contaminated leachate with a short reaction time. Therefore, the soil washing method technology is a good method to remove the initial radioactive substance. The soil dimension compositions consist of clay with small particle sizes, and gravel of larger particle sizes than clay. Also, large gravel creates several problems. Gravel weakens the intensity of the equipment. In addition, intercept soil is discharged in the equipment. And interfere with the pedal recurrence occurs. Therefore, it is necessary to classify the soil. The gravel particle size ranges from 0.5cm to 7.5cm and the granulated gravel particle size ranges from 7.5cm to 20cm. We suppose that the radioactive concentrations are stronger in soil particles larger than the soil particle size (below a 0.5cm diameter). The purpose of this study is to develop a soil washing system for uranium gravel and to define the most suitable operational conditions for the individual elemental equipment in a soil washing system for decontaminating the radioactive gravel from contaminated soil

  17. Removal of uranium from gravel using soil washing method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ilgook; Kim, Kye-Nam; Kim, Seung-Soo; Choi, Jong-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The development of nuclear technology has led to increasing radioactive waste containing uranium being released and disposed in the nuclear sites. Fine grained soils with a size of less than 4 mm are normally decontaminated using soil washing and electro-kinetic technologies. However, there have been few studies on the decontamination of gravels with a size of more than 4 mm. Therefore, it is necessary to study the decontamination of gravel contaminated with radionuclides. The main objective of the present study on soil washing was to define the optimal condition for acid treatment of uranium-polluted gravel. In this study, soil washing method was applied to remove uranium from gravel. The gravel was crushed and classified as particle sizes. The gravel particles were treated with sulfuric acid in a shaking incubator at 60 .deg. C and 150 rpm for 3 h. The optimal particle size of gravel for soil washing in removal of uranium was between 0.45 and 2.0 mm.

  18. Experiment on Physical Desalinisation of Uranium-contaminated Gravel Surface

    International Nuclear Information System (INIS)

    Park, Uk-Ryang; Kim, Gye-Nam; Kim, Seung-Soo; Han, Gyu-Seong; Moon, Jai-Kwon

    2014-01-01

    As a result, the method to wash uranium-contaminated gravels could not get satisfactory desalinization rate. During the long oxidization process it was judged that uranium penetrated inside the gravels, so we tried to increase the desalinization rate by fragmentizing them into pieces and then washing them. The desalinization rate after fragmentizing the gravels into pieces and washing them brought a satisfactory result.. However, we could obtain desired concentration for gravels with high uranium concentration by fragmentizing them and breaking them further into even smaller pieces. Likewise, desalinization using soil washing process is complicated and has to go through multiple washing steps, resulting in too much of waste fluid generated accordingly. The increase of waste fluid generated leads to the increase in by-products of the final disposal process later on, bringing a not good economic result. Furthermore, taking into account that the desalinization rate is 65% during soil washing process, it is expected that gravel washing will show a similar desalinization result; it is considered uneasy to have a perfect desalinization only by soil washing. The grinding method is actually used in the primary desalinization process in order to desalinize radioactivity-contaminated concrete. This method does desalinization by grinding the radioactivity-contaminated area of the concrete surface with desalinization equipment, which enables a near-to-perfect desalinization for relatively thinly contaminated surface. Likewise, this research verified the degree of desalinization by applying the grinding method and comparing it to the fragmentizing-washing method, and attempted to find a method to desalinize uranium-contaminated gravels more effectively. In order to desalinize uranium-contaminated gravels more effectively and compare to the existing washing-desalinization method, we conducted a desalinization experiment with grinding method that grinds gravel surface. As a

  19. Quantification of Gravel Rural Road Sediment Production

    Science.gov (United States)

    Silliman, B. A.; Myers Toman, E.

    2014-12-01

    Unbound rural roads are thought to be one of the largest anthropogenic sources of sediment reaching stream channels in small watersheds. This sediment deposition can reduce water quality in the streams negatively impacting aquatic habitat as well as impacting municipal drinking water sources. These roads are thought to see an increase in construction and use in southeast Ohio due to the expansion of shale gas development in the region. This study set out to quantify the amount of sediment these rural roads are able to produce. A controlled rain event of 12.7 millimeters of rain over a half hour period was used to drive sediment production over a 0.03 kilometer section of gravel rural road. These 8 segments varied in many characteristics and produced from 2.0 to 8.4 kilograms of sediment per 0.03 kilometers of road with the average production over the 8 segments being 5.5 kilograms of sediment. Sediment production was not strongly correlated with road segment slope but traffic was found to increase sediment production from 1.1 to 3.9 times as much sediment after traffic use. These results will help inform watershed scale sediment budgeting, and inform best management practices for road maintenance and construction. This study also adds to the understanding of the impacts of rural road use and construction associated with the changing land use from agricultural to natural gas extraction.

  20. Sorption of activation products on London clay and Dungeness aquifer gravel

    Energy Technology Data Exchange (ETDEWEB)

    Baston, G.M.N.; Berry, J.A.; Littleboy, A.K.; Pilkington, N.J. (AEA Decommissioning and Radwaste, Harwell Lab. (United Kingdom))

    1992-01-01

    The sortpion of a series of activation-product radionuclides onto London clay and Dungeness aquifer gravel from the nuclear reactor sites at Bradwell and Dungeness, has been examined. Batch sorption and through-diffusion experiments with clay determined chlorine as the chloride ion to be effectively non-sorbing; calcium to be weakly sorbing, whereas cobalt, nickel, niobium and samarium were moderately to strongly sorbing and silver was strongly sorbing. Distribution ratios (R[sub D] values) for Nb, Sm and Ag were found to have a strong dependence on the liquid-solid separation technique employed. The presence of high concentrations of calcium hydroxide led to lower values of R[sub D] for radioactive Ca but higher R[sub D] values for Sm and Ag. The sorption of Ni showed no apparent dependence on groundwater composition at low levels of dissolved organic carbon (DOC). The values of R[sub D] for Co decreased as the DOC content was increased by addition of humic materials. Batch sorption studies with aquifer gravel demonstrated that Ca is weakly sorbing whereas Nb, Ag and Eu are moderately to strongly sorbing. R[sub D] values for Ca and for Ag under neutral pH conditions show little sensitivity to the liquid/solid separation technique used. However, R[sub D] values for Nb and Eu under neutral pH conditions and for Ag in alkaline solution (pH = 11 - 12) show a marked effect. The aquifer gravel was found to be highly inhomogeneous unlike the clay and sorption was greatest on samples with a high proportion of sand, reflecting the clay mineral content. (orig.).

  1. Sorption of activation products on London clay and Dungeness aquifer gravel

    International Nuclear Information System (INIS)

    Baston, G.M.N.; Berry, J.A.; Littleboy, A.K.; Pilkington, N.J.

    1992-01-01

    The sortpion of a series of activation-product radionuclides onto London clay and Dungeness aquifer gravel from the nuclear reactor sites at Bradwell and Dungeness, has been examined. Batch sorption and through-diffusion experiments with clay determined chlorine as the chloride ion to be effectively non-sorbing; calcium to be weakly sorbing, whereas cobalt, nickel, niobium and samarium were moderately to strongly sorbing and silver was strongly sorbing. Distribution ratios (R D values) for Nb, Sm and Ag were found to have a strong dependence on the liquid-solid separation technique employed. The presence of high concentrations of calcium hydroxide led to lower values of R D for radioactive Ca but higher R D values for Sm and Ag. The sorption of Ni showed no apparent dependence on groundwater composition at low levels of dissolved organic carbon (DOC). The values of R D for Co decreased as the DOC content was increased by addition of humic materials. Batch sorption studies with aquifer gravel demonstrated that Ca is weakly sorbing whereas Nb, Ag and Eu are moderately to strongly sorbing. R D values for Ca and for Ag under neutral pH conditions show little sensitivity to the liquid/solid separation technique used. However, R D values for Nb and Eu under neutral pH conditions and for Ag in alkaline solution (pH = 11 - 12) show a marked effect. The aquifer gravel was found to be highly inhomogeneous unlike the clay and sorption was greatest on samples with a high proportion of sand, reflecting the clay mineral content. (orig.)

  2. Developing new markets for oil sands products

    International Nuclear Information System (INIS)

    Crandall, G.

    2004-01-01

    This paper presents a review by Purvin and Gertz of western Canadian crude oil supply. This energy consulting firm provides advise to the energy sector. It suggests that oil sands production will surpass declining conventional production. Oil sands supply includes bitumen, synthetic crude oil (SCO), and diluent. It is forecasted that oil sands will increase from 42 per cent of western supply in 2002 to 78 per cent in 2015. The potential of Alberta's oil sands was discussed along with a recent study of refined products and petrochemicals from bitumen. Upgrading, refining and petrochemical case studies were presented. The author examined if a Canadian oil sands upgrading project with high capital costs can be competitive with competing projects in the United States and internationally. In addition to supply and demand issues, the presentation examined infrastructure capability and market potential in the United States. The economic potential and risks of preferred business cases compared to upgrading to SCO were also evaluated. 15 figs

  3. Application of ELJ to create and maintain side channels in a dynamic gravel bed river

    Science.gov (United States)

    Crabbe, E.; Crowe Curran, J.; Ockelford, A.

    2017-12-01

    Braided and anastomosing rivers create and maintain a large amount of side channel habitat. Unfortunately, many rivers that were once multi-channel rivers have been constrained to single thread channels as a consequence of land use changes that occurred in the 19th and 20th centuries or earlier. An increasingly common management goal today is the re-creation of self-maintaining side and tributary habitat through as natural means as possible. This work examines the geomorphic history of one such channel and the success of recent rehabilitation efforts. Our case study comes from the South Fork Nooksack River in the Cascades Range in Washington State. The Nooksack River is a gravel and sand bed channel with a snowmelt dominated hydrograph. Engineered log jams (ELJ) have been employed to direct flow into side and chute channels with the larger goals of increasing overall channel complexity and salmon spawning opportunities. ELJs have been constructed on the channel since the 2000s, and the ELJs in the study reaches range in age up to 10 years. The size and design of individual jams within the reach vary, enabling a comparison between jam types. ELJs are evaluated for their ability to maintain gravel bar locations and open tributary channels through the snowmelt season over the reach scale. Additional goals of trapping wood onto the jams and existing bars, stabilizing channel banks, and allowing for the growth of bar vegetation are also examined.

  4. Gravel addition as a habitat restoration technique for tailwaters

    Science.gov (United States)

    Ryan McManamay; D. Orth; Charles Dolloff; Mark Cantrell

    2010-01-01

    We assessed the efficacy of passive gravel addition at forming catostomid spawning habitat under various flow regimes in the Cheoah River, a high-gradient tailwater river in North Carolina. The purpose was to provide a case study that included recommendations for future applications. A total of 76.3 m3 (162 tons) of washed gravel (10-50 mm) was passively dumped down...

  5. 32 CFR 644.505 - Disposal plan for embedded gravel, sand or stone.

    Science.gov (United States)

    2010-07-01

    ... or level to which the material may be removed, and any restoration of the site after removal. (d... familiar with the material involved and the operations for mining, quarrying or otherwise removing it...

  6. Transport and mass exchange processes in sand and gravel aquifers (v.1)

    International Nuclear Information System (INIS)

    Moltyaner, G.

    1990-01-01

    The objectives of this conference were to exchange information on promising field measurement techniques used for the characterization of spatial variability of geologic formations and on new methods used for quantifying the effect of spatial variability on groundwater flow and transport of materials; to discuss novel developments in the theory of transport processes and simulation methods; and to present views and opinions on future initiatives and directions in the design of large-scale field tracer experiments and the development of conceptual and mathematical models of transport and mass exchange processes. The 46 papers presented in these proceedings are divided into six sections: field studies of transport processes; groundwater tracers and novel field measurement techniques; promising methods and field measurement techniques for quantifying the effect of geological heterogeneities on groundwater flow and transport; novel developments in the theory of transport processes; numerical modelling of transport and mass exchange processes; and field and modelling studies of mass exchange processes. (L.L.)

  7. From gravel to sand. Downstream fining of bed sediments in the lower river Rhine

    NARCIS (Netherlands)

    Frings, R.M.

    2007-01-01

    A common characteristic of many rivers is the tendency for bed sediments to become finer in downstream direction. This phenomenon, which is generally known as downstream fining, has a strong effect on the morphologic and hydrodynamic behaviour of a river. The fundamental causes of downstream

  8. Computational fluid dynamics and experimental tests helping to understand the gravel pack displacement in petroleum wells; Fluidodinamica computacional (CFD) e testes experimentais ajudam a compreender o fenomeno do deslocamento do gravel pack em pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Joao Vicente Martins de; Leal, Rafael Amorim Ferreira; Martins, Andre Leibsohn; Calderon, Agostinho; Ferreira, Marcus Vinicius Duarte [Petrobras S.A., Rio de Janeiro, RJ (Brazil)], E-mails: ivmm@petrobras.com.br, rafaelleal@petrobras.com.br, aleibsohn@petrobras.com.br, agoscal@petrobras.com.br, mvdferreira@petrobras.com.br; Simoes, Bruno; Barbosa, Diego [Halliburton, Novo Cavaleiros, Macae, RJ (Brazil)], E-mails: bruno.simoes@halliburton.com.br, diego.barbosa@halliburton.com.br

    2010-07-01

    In the petroleum exploitation and production in deep water, at the fields operated by PETROBRAS, Brazil, one of the problems frequently found is the need of elimination of sand production, having in mind that the most of those fields produce from the non consolidated sandstones. The opened well Gravel Packing is the technique most used for that task. Due to the fact of Gravel Packing operations occurs at thousand of meters below the surface, it is necessary the computational simulation for forecasting how particle deposition (Gravel) in the well occurs. So, it was used the commercial pack of fluid dynamics FLUENT 12, which calculates the fluid velocity field, coupled to another commercial pack, the EDEM, based on discrete elements that treat of particle mechanics. The coupling of the two software has shown adequate the comparison of the computational results with the experimental data shows a good adjustment. Besides, it was possible to simulate problems of well early clogging, showing that the computational simulation is strong and capable of captivating such a phenomena.

  9. Experimental tests and computational fluid dynamics (CFD) helps in determination the new operational limits for gravel packing; Testes experimentais e simulacoes em fluidodinamica computacional (CFD) auxiliam na determinacao de novos limites operacionais para o gravel packing

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Joao Vicente Martins de [PETROBRAS, Santos, SP (Brazil). E e P Construcao de Pocos Maritimos. Construcao e Manutencao de Pocos], e-mail: jvmm@petrobras.com.br; Calderon, Agostinho [PETROBRAS, rj (bRAZIL). E e P Construcao de Pocos Maritimos. Construcao e Manutencao de Pocos], e-mail: agoscal@petrobras.com.br; Leal, Rafael Amorim Ferreira [Centro de Pesquisas da Petrobras (CENPES), RJ (Brazil). P e D em Geoengenharia e Engenharia de Poco. Gerencia de Perfuracao e Completacao de Pocos], e-mail: rafaelleal@petrobras.com.br; Miranda, Daniel Bonavides [Halliburton Energy Services (Brazil)], e-mail: daniel.miranda@halliburton.com; Simoes, Bruno Campos; Nunes, Mauro Jose de Souza Custodio [Halliburton Brasil. Setor de Estimulacao e Controle de Areia (Brazil)], e-mails: bruno.simoes@halliburton.com, mauro.nunes@halliburton.com; Barbosa, Diego Paiva [Halliburton Brasil. Coordenador de Servicos de Campo (Brazil)], e-mail: diego.barbosa@halliburton.com; Souza, Jairo Zago de [Engineering Simulation and Scientific Software - ESSS (Brazil)], e-mail: jairo@esss.com.br

    2010-06-15

    Open hole Gravel Packing was the sand control strategy adopted by PETROBRAS while developing Campos Basin fields. One of the big problems in the oil industry is based on stems from the fact of that all the whole operations are carried out many thousands of feet in the underground, without direct visualization supervision. All the controls used in the operations are based upon direct and/or indirect measurements, but without, however, the necessary visual aid. This was the motivator for the construction of an experimental device that could simulate both the open well and the rat-hole allowing the study of how the deposition of Gravel occurs around the screens. Such experimental apparatus was built with casing pipes it which common rat-hole/open-hole inside diameters (12 1/'' and 8 1/2''). For the tests representativeness the simulator was equipped with real screens and wash pipes, reproducing the real operation dynamics. In the apparatus it was possible: to see Gravel settling through acrylic windows, to test new low-cost proppants and new concentrations, to define new minimal pump operational rates, as well as to record by filming the turbulent structures that occurs at the rat-hole/open-hole contraction zone. This paper treats of these results release and show CFD results used to enlarge test matrix. (author)

  10. A method for limiting sand production in wells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L M

    1983-09-01

    A method is patented which makes it possible to substantially limit sand falling into a well of an operational stratum which is made up of weakly cemented rocks. The presently known methods for controlling sand carry away into a well in the majority of cases provide for the installation in its bottom hole of a special filter. The winding of a sand and gravel filter is the most common. Serious problems associated with the difficulty in testing the winding process must be dealt with in this, as well as the use of additional equipment. The patented method lies in installing a specially made pipe filter in the bottom hole. The filtering element is the walls of the filter itself, which are made of a porous material. An important characteristic of the filter is the size of its pores which causes the filtration purity. The size of the pipe filter may be from 10 to 200 meters depending on the exploitation conditions.

  11. Applications of sand control technology in thermal recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Rensvold, R F

    1982-01-01

    The ever-increasing application of thermal methods to recover low gravity crude oil has warranted the review of existing sand control techniques relative to their compatibility with high temperature environments. The advantages and limitations of a large number of materials are considered. Carrying fluids, granular pack solids, clay stabilizers, and resin-coated pack sands are discussed. Resins used for in situ sand consolidation processes also are reviewed, and their suitability for application in a high temperature steam environment is evaluated. The effects of highly deviated boreholes on the placement of pressure packs also are considered. Full scale gravel pack model studies have provided valuable clues to the procedures and materials that help to create optimum pressure packs. 58 references.

  12. Washing technology development for gravel contaminated with uranium

    Energy Technology Data Exchange (ETDEWEB)

    Park, Uk Ryang; Kim, Gye Nam; Kim, Seung Soo; Kim, Wan Suk; Moon, Jai Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    The soil washing method has a short decontamination time and is economical. In addition, methods including phytoremediation, solidification/stabilization and bioremediation exist. Phytoremediation and bioremediation are economical, but have low remedial efficiency. In addition, bioremediation causes washing wastewater because it requires a washing process for the separation of microorganisms from the soils. In addition, solidification/stabilization is a commonly used methods, but eventually increases the volume of wastes. As mentioned above, many researches involved in the decontamination of radioactively contaminated soils have been actively processed. On the other hand, researches for decontaminating radioactively contaminated gravels are not being currently processed. In this study, we performed basic experiments using decontamination methods to decontaminate radioactively contaminated gravel. First, we measured the concentration of uranium in gravel included in uranium-contaminated soils and performed a washing experiment to monitor the tendency of uranium removal. In addition, when managing gravel with a low uranium-decontamination rate, we tried to satisfy the radioactivity concentration criteria for self-disposal in the wastes (0.4Bq/g or less) by performing a washing experiment after only a physical crushing process. We performed washing experiments to satisfy the radioactivity concentration criteria for self-disposal (0.4 Bq/g or less) in gravel included in radioactively contaminated soil. We performed washing experiments for gravel whose initial average concentration of uranium was 1.3Bq/g. In addition, the average concentration of uranium was 0.8Bq/g. Too increase the decontamination rate, we crushed the gravel with a jaw crusher and performed the washing experiments. The results were similar to the results without crushing. In addition, it was determined that the smaller the size of the gravel particles, the more efficient the uranium decontamination

  13. The Effect of the Kind of Sands and Additions on the Mechanical Behaviour of S.C.C

    Science.gov (United States)

    Zeghichi, L.; Benghazi, Z.; Baali, L.

    The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates. The effect of additions is also treated (blast furnace slag and lime stone) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

  14. Evaluation of multistage filtration to reduce sand filter exhaust activity

    International Nuclear Information System (INIS)

    Zippler, D.B.

    1975-01-01

    Air from the Savannah River Plant Fuel Reprocessing facilities is filtered through deep bed sand filters consisting of 8 1 / 2 feet of gravel and sand. These filters have performed satisfactorily for the past 18 years in maintaining radioactive release levels to a minimum. The apparent filter efficiency has been determined for many years by measurements of the quantity of radioactivity in the air stream before and after the filter. Such tests have indicated efficiencies of 99.9 percent or better. Even with sand filter efficiency approaching a single stage HEPA filter, new emphasis on further reduction in release of plutonium activity to the environment prompted a study to determine what value backup HEPA filtration could provide. To evaluate the specific effect additional HEPA filtration would have on the removal of Pu from the existing sand filter exhaust stream, a test was conducted by passing a sidestream of sand-filtered air through a standard 24 x 24 x 11 1 / 2 in. HEPA filter. Isokinetic air samples were withdrawn upstream and downstream of the HEPA filter and counted for alpha activity. Efficiency calculations indicated that backup HEPA filtration could be expected to provide an additional 99 percent removal of the Pu activity from the present sand-filter exhaust. (U.S.)

  15. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...... will described. In this connection, the procedure for preparation of the soil specimens will be presented, and the actual performance of the tests will be briefly outlined. Finally, the procedure for processing of the measurements from the laboratory in order to obtain usable data will be described. The final...

  16. Treatment of Gravel Contaminated with Naturally Occurring Radioactive Element

    International Nuclear Information System (INIS)

    Sohsah, M. A.; Kamal, S. M.; Mamoon, A.

    2004-01-01

    Environmental protection primarily means controlling the releases of radioactive and non-radioactive wastes to the environment and involves treatment, storage, cleanup and disposal of these wastes. The present study concerns the cleanup of gravel that has been contaminated with 2 26 R a. Aqueous solutions of different compositions including water and various concentrations of calcium chloride and barium chloride were used to leach the contaminated gravel. The leaching experiments were carried out in glass column. In some leaching experiments, samples of sandy soil were placed below the gravel to test the sorption of the leached 2 26 R a by the soil. The relative efficiencies of the leachant and the extent of sorption of the leached radionuclide were determined both by the liquid scintillation counting and by the thermoluminescent chips. The TLD chips record the dose before and after decontamination of the gravel and before and after contamination of the soil samples when used. The results obtained indicated that acidified barium chloride was relatively the most effective leachant of 2 26 R a contamination. It reduced the dose from the contaminated gravel to almost half. The soil sample used adsorbs the leached radionuclides efficiently, increasing the soil naturally low dose to about six folds

  17. Leaching of RA-226 contaminated gravel using different aqueous treatments

    Energy Technology Data Exchange (ETDEWEB)

    Mamoon, A; Abulfaraj, W H; Sohsah, M A [King Abdulaziz University, Jeddah, Saudi Arbabia (Saudi Arabia)

    1997-12-31

    Investigation of the efficiencies of different aqueous leaching treatments was carried out on gravel artificially contaminated with Ra-226. The extent of leaching efficiency was determined in terms of Ra-226 and its daughter Rn-222. Liquid scintillation counting using high efficiency mineral oil based liquid scintillator was the technique adopted for measuring Ra-226 and Rn-222 leached off the contaminated gravel. Water, dilute solutions of barium chloride and HCl were used as leachants. Different masses of gravel were leached with 200 mL of leachant for various contact time periods. The leached Rn-222 activity measured was plotted vs the decay factor e; from which Rn-222 and Ra-226 originally present in the sample were determined. Several leaching parameters were tested; namely type of leachant, leachant volume/gravel mass ratio, leachant contact time, effect of varying Ba Cl{sub 2} concentration, and successive leaching. Optimization of the leaching parameters for desorption of Ra-226 off the contaminated gravel under laboratory conditions may help determine the ideal conditions for remediating soil contaminated with radium or chemically similar radionuclides. 7 figs.

  18. Turbidity removal: Gravel and charcoal as roughing filtration media

    Directory of Open Access Journals (Sweden)

    Josiah A. Adeyemo

    2010-10-01

    Full Text Available Roughing filtration is an important pre-treatment process for wastewater, because it efficiently separates fine solid particles over prolonged periods, without the addition of chemicals. For this study, a pilot plant was designed at Delmas Coal Mine in the Mpumalanga province of South Africa. The design and sizing of the pilot plant was guided by Wegelin’s design criteria. Gravel was used as a control medium because it is one of the most commonly used roughing filter media and because it was used in developing the criteria. We compared the performance of gravel as a filter medium to that of another locally available material, charcoal, for the removal of turbidity in wastewater. The pilot plant was monitored continuously for 90 days from commissioning until the end of the project. The overall performance of the roughing filter in turbidity removal, using gravel or charcoal, was considered efficient for the pre-treatment of waste water. Charcoal performed slightly better than gravel as a filter medium for the removal of turbidity, possibly because charcoal has a slightly higher specific surface area and porosity than gravel, which could enhance sedimentation and other filtration processes, such as adsorption, respectively.

  19. Stratigraphic framework of sediment-starved sand ridges on a mixed siliciclastic/carbonate inner shelf; west-central Florida

    Science.gov (United States)

    Edwards, J.H.; Harrison, S.E.; Locker, S.D.; Hine, A.C.; Twichell, D.C.

    2003-01-01

    Seismic reflection profiles and vibracores have revealed that an inner shelf, sand-ridge field has developed over the past few thousand years situated on an elevated, broad bedrock terrace. This terrace extends seaward of a major headland associated with the modern barrier-island coastline of west-central Florida. The overall geologic setting is a low-energy, sediment-starved, mixed siliciclastic/carbonate inner continental shelf supporting a thin sedimentary veneer. This veneer is arranged in a series of subparallel, shore-oblique, and to a minor extent, shore-parallel sand ridges. Seven major facies are present beneath the ridges, including a basal Neogene limestone gravel facies and a blue-green clay facies indicative of dominantly authigenic sedimentation. A major sequence boundary separates these older units from Holocene age, organic-rich mud facies (marsh), which grades upward into a muddy sand facies (lagoon or shallow open shelf/seagrass meadows). Cores reveal that the muddy shelf facies is either in sharp contact or grades upward into a shelly sand facies (ravinement or sudden termination of seagrass meadows). The shelly sand facies grades upward to a mixed siliciclastic/carbonate facies, which forms the sand ridges themselves. This mixed siliciclastic/carbonate facies differs from the sediment on the beach and shoreface, suggesting insignificant sediment exchange between the offshore ridges and the modern coastline. Additionally, the lack of early Holocene, pre-ridge facies in the troughs between the ridges suggests that the ridges themselves do not migrate laterally extensively. Radiocarbon dating has indicated that these sand ridges can form relatively quickly (???1.3 ka) on relatively low-energy inner shelves once open-marine conditions are available, and that frequent, high-energy, storm-dominated conditions are not necessarily required. We suggest that the two inner shelf depositional models presented (open-shelf vs. migrating barrier-island) may

  20. Liquid filtration properties in gravel foundation of railroad tracks

    International Nuclear Information System (INIS)

    Strelkov, A; Teplykh, S; Bukhman, N

    2016-01-01

    Railway bed gravel foundation has a constant permanent impact on urban ecology and ground surface. It is only natural that larger objects, such as railway stations, make broader impact. Surface run-off waters polluted by harmful substances existing in railroad track body (ballast section) flow along railroad tracks and within macadam, go down into subterranean ground flow and then enter neighbouring rivers and water basins. This paper presents analytic calculations and characteristics of surface run-off liquid filtration which flows through gravel multiple layers (railroad track ballast section). The authors analyse liquids with various density and viscosity flowing in multi-layer porous medium. The paper also describes liquid stationary and non-stationary weepage into gravel foundation of railroad tracks. (paper)

  1. Least tern and piping plover nesting at sand pits in Nebraska

    Science.gov (United States)

    Sidle, John G.; Kirsch, E.M.

    1993-01-01

    Endangered Least Terns (Sterna antillarum) and threatened Piping Plovers (Charadrius melodus) nest at commercial sand and gravel mining operations (sand pits) along the Platte River system in Nebraska. Sandbar habitat has been disappearing since the early 1900's along the Platte River system, but numbers of sand pits have increased. We hypothesized that birds would more fully utilize sand pits where suitable sandbar habitat was limited. We inventoried sand pits and censused terns and plovers on both habitats along the Loup River, part of the North Loup River, and most of the Platte River during 1988-1991. Using aircraft, we also quantified features of suitable sand pits present on the central Platte in 1988 and lower Platte in 1990, and related features to abundance and presence of birds. We found 225 sand pits of which 78 were suitable and 187 were unsuitable for nesting. Along the central Platte, where sandbar habitat is severely degraded, birds nested at 81% of the suitable sand pits (N = 32) at least once during 1988-1991, and most birds (61-94%) nested on sand pits. Along the lower Platte, where both sandbar and sand pit habitat are plentiful, birds nested at 60% of the suitable sand pits (N = 35) at least once during 1988-1991, and most birds (60-86%) nested on sandbars. Numbers of terns and plovers were more weakly correlated with features of sand pits on the central Platte than on the lower Platte. Least Terns and Piping Plovers seem to use more of the suitable sand pit habitat on the central Platte than on the lower Platte. Sand pits probably have influenced the birds' distribution by providing alternative nesting habitat along rivers where suitable sandbars are rare or absent.

  2. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  3. Stabilizing cinder gravels for heavily trafficked base course ...

    African Journals Online (AJOL)

    Investigation into the improvement of natural cinder gravels with the use of stabilization techniques was made using samples collected from quarry sites near Alemgena and Lake Chamo. Mechanical and cement stabilizations were investigated in two subsequent phases. In the first phase, optimum amount of fine soils that ...

  4. stabilization of cinder gravel with cment for base course

    African Journals Online (AJOL)

    Girma Berhanu

    techniques was made using samples collected from quarry sites near ... design standards for heavily trafficked base course without adding ... Cinder gravel, Mechanized stabilization, Optimum cement content ... respectively. In the presentation through out the .... here to indicate the general response of cement stabilization in ...

  5. Singing Sand Dunes

    Indian Academy of Sciences (India)

    ble low-frequency (s. 75–105 Hz), that can some- times be heard up to 10 km away. Scientific in- vestigations suggest that the sustained low fre- quency sound of sand dunes that resembles a pure note from a musical instrument, is due to the synchronized motion of well-sorted dry sand grains when they spontaneously ...

  6. Laboratory test on maximum and minimum void ratio of tropical sand matrix soils

    Science.gov (United States)

    Othman, B. A.; Marto, A.

    2018-04-01

    Sand is generally known as loose granular material which has a grain size finer than gravel and coarser than silt and can be very angular to well-rounded in shape. The present of various amount of fines which also influence the loosest and densest state of sand in natural condition have been well known to contribute to the deformation and loss of shear strength of soil. This paper presents the effect of various range of fines content on minimum void ratio e min and maximum void ratio e max of sand matrix soils. Laboratory tests to determine e min and e max of sand matrix soil were conducted using non-standard method introduced by previous researcher. Clean sand was obtained from natural mining site at Johor, Malaysia. A set of 3 different sizes of sand (fine sand, medium sand, and coarse sand) were mixed with 0% to 40% by weight of low plasticity fine (kaolin). Results showed that generally e min and e max decreased with the increase of fines content up to a minimal value of 0% to 30%, and then increased back thereafter.

  7. Effects of gravel mulch on emergence of galleta grass seedlings

    International Nuclear Information System (INIS)

    Winkel, V.K.; Medrano, J.C.; Stanley, C.; Walo, M.D.

    1993-03-01

    The Department of Energy Nevada Operations Office, Technology Development and Program Management Division, has identified the need to clean up several sites on the Nevada Test Site and Tonopah Test Range contaminated with surface plutonium. An important objective of the project identified as the Plutonium In Soils Integrated Demonstration is to develop technologies to stabilize and restore the disturbed sites after decontamination. Revegetation of these contaminated sites will be difficult due to their location in the arid Mojave and Great Basin Deserts. The major factors which will affect successful plant establishment and growth at these sites are limited and sporadic precipitation, limited soil water, extreme air and soil temperatures, limited topsoil, and herbivory . Research has shown that providing microsites for seed via mulching can aid in plant emergence and establishment. Since many of the soils at the sites slated for plutonium decontamination have a large percentage of gravel in the upper 10 cm of soil, the use of gravel as mulch could provide microsites for seed and stabilize soils during subsequent revegetation of the sites. In July 1992, EG ampersand G/EM Environmental Sciences Department initiated a greenhouse study to examine the possible benefits of gravel mulch. The specific objectives of this greenhouse study were to: (1) determine the effects seedling emergence and soil water, and (2) determine effects of irrigation rates on seedling emergence for gravel mulches and other conventional seedbed preparation techniques. A secondary objective was to determine the depth of gravel mulch that was optimal for seedling emergence. Results from this greenhouse study will assist in formulating specific reclamation plans for sites chosen for cleanup

  8. New generation expandable sand screens

    OpenAIRE

    Syltøy, Christer

    2014-01-01

    Master's thesis in Petroleum engineering This thesis aims to give a general insight into sand control and various sorts of sand control measures and applications of sand control tools. Special focus will be given to expandable sand screens – a technology which came about in the late 1990’s through the use of flexible, expandable tubulars as base pipe in sand screens. More specifically Darcy’s Hydraulic Endurance Screens, a compliant sand screen system using hydraulic activation, and the fu...

  9. Retorting of bituminous sands

    Energy Technology Data Exchange (ETDEWEB)

    Chaney, P E; Ince, R W; Mason, C M

    1872-09-26

    This method of recovering oil from mined tar sands involves forming compacted tar sands pieces by special conditioning treatment that provides low internal permeability. The compacted pieces are then retorted in fixed bed form. The conditioning treatment can involve rolling of preformed pellets, compaction in a mold or pressure extrusion. Substantial collapsing of the bed during retorting is avoided. (9 claims) (Abstract only - original article not available from T.U.)

  10. A 2D hydrodynamic-sedimentological model for gravel-bed rivers. Part I: theory and validation

    Directory of Open Access Journals (Sweden)

    Gabriel Kaless

    2013-09-01

    Full Text Available This paper presents a novel 2D-depth average model especially developed for gravel-bed rivers, named Lican-Leufú (Lican=pebble and Leufu=river, in Mapuche’s language, the native inhabitants of Central Patagonia, Argentina. The model consists of three components: a hydrodynamic, a sedimentological, and a morphological model. The flow of water is described by the depth-averaged Reynolds equations for unsteady, free-surface, shallow water flows. It includes the standard k-e model for turbulence closure. Sediment transport can be divided in different size classes (sand-gravel mixture and the equilibrium approach is used for Exner’s equation. The amour layer is also included in the structure of the model and the surface grain size distribution is also allowed to evolve. The model simulates bank slides that enable channel widening. Models predictions were tested against a flume experiment where a static armour layer was developed under conditions of sediment starvations and general good agreements were found: the model predicted adequately the sediment transport, grain size of transported material, final armour grain size distribution and bed elevation.

  11. Evidence for aeolian origins of heuweltjies from buried gravel layers

    Directory of Open Access Journals (Sweden)

    Michael D. Cramer

    2016-02-01

    Full Text Available Although heuweltjies (19–32 m diameter dominate the surface of much of the southwestern Cape of South Africa, their origins, distribution and age remain controversial. Current hypotheses are that the heuweltjies are (1 constructed by the excavation and mounding habits of burrowing animals; (2 the result of erosion by water of areas between patches protected from fluvial action by denser vegetation or (3 the product of localised aeolian sediment accumulation beneath denser vegetation associated with termitaria. At a site where quartz-containing gravels occur on the soil surface in areas between heuweltjies, these gravels were found to extend as a relatively intact layer of uniform concentration from the inter-mound area into the mound at the same plane as the surrounding soil surface. This buried layer suggests that heuweltjies were either built-up by deposition on a previous soil surface layer or eroded from sediment accumulated above the buried gravel layer. Mounds contain a relatively large proportion of silt consistent with sediment deposition. Mound sediment elemental composition was strongly correlated with that of local shale, indicating a local source of sediment. Pedogenesis was considerably more advanced off- than on-mound. There was no evidence of extensive regional aeolian sediment mantling over the vast area in which the heuweltjies occur. These findings and observations support the aeolian deposition hypothesis of heuweltjie origins combined with a degree of erosion, rather than a termite bioturbation hypothesis or a predominantly erosion-based hypothesis.

  12. Measurement of earthquake-induced shear strain in sandy gravel

    International Nuclear Information System (INIS)

    Ohkawa, I.; Futaki, M.; Yamanouchi, H.

    1989-01-01

    The nuclear power reactor buildings have been constructed on the hard rock ground formed in or before the Tertiary in Japan. This is mainly because the nuclear reactor building is much heavier than the common buildings and requires a large bearing capacity of the underlying soil deposit, and additionally the excessive deformation in soil deposit might cause damage in reactor building and subsequently cause the malfunction of the internal important facilities. Another reason is that the Quaternary soil deposit is not fully known with respect to its dynamic property. The gravel, and the sandy gravel, the representative soils of the Quaternary, have been believed to be suitable soil deposits to support the foundation of a common building, although the soils have rarely been investigated so closely on their physical properties quantitatively. In this paper, the dynamic deformability, i.e., the shear stress-strain relationship of the Quaternary diluvial soil deposit is examined through the earthquake ground motion measurement using accelerometers, pore-pressure meters, the specific devices developed in this research work. The objective soil deposit in this research is the sandy gravel of the diluvial and the alluvial

  13. Evolution of completion tools gravel pack systems for deep water

    Energy Technology Data Exchange (ETDEWEB)

    Pineda, Francisco [BJ Services Company, Houston, TX (United States); Vilela, Alvaro; Montanha, Roberto; Hightower, Chad; Acosta, Marco; Farias, Rodrigo [BJ Services do Brasil Ltda., Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Conventional gravel pack or frac pack completions typically require the use of wash pipe to act as a conduit for fluid returns as well as to carry a shifting mechanism to open or close a return port. Using properly sized wash pipe can enhance the placement of the gravel across the entire annular space and the formation. It can also be used in conjunction with a shifting mechanism and a sliding sleeve to force the fluid returns to pass through the bottom of the screen. It can allow a wash-down capability while running the assembly into an open hole. In specialty systems, it can even act as a pumping conduit for post-gravel pack stimulation. However, the use of wash pipe, especially in long horizontal wells, means the loss of valuable rig time due to make up and break out of the wash pipe, or recovery if the wash pipe is stuck. Economic considerations, along with completion efficiencies, are especially important on deep water completions. Not using wash pipe reduces rig time, generating significant cost savings, and also eliminates the risk of a fishing operation. This paper reviews conventional wash pipe applications and describes new systems that accomplish the same goal with a minimum amount of wash pipe or no wash pipe at all. (author)

  14. Comparison of different forms of gravel as aggregate in concrete

    Directory of Open Access Journals (Sweden)

    Sikiru ORITOLA

    2014-11-01

    Full Text Available Gradation plays an important role in the workability, segregation, and pump ability of concrete. Uniformly distributed aggregates require less paste which will also decrease bleeding, creep and shrinkage while producing better workability, more durable concrete and higher packing. This attempt looks at the effect of particle size distribution pattern for five types of gravel aggregate forms, angular, elongated, smooth rounded, irregular and flaky as related to the strength of concrete produced. Different forms of naturally existing gravel aggregate were collected from a particular location and tests were carried out on them to determine their gradation. Based on the gradation the aggregates were used to prepare different samples of grade 20 concrete with water-cement ratio of 0.5. The particle size distribution resulted in coefficients of uniformity ranging from 1.24 to 1.44. The granite aggregate, which serves as a reference, had a coefficient of uniformity of 1.47. Tests were conducted on fresh and hardened concrete cube samples. The concrete sample CT5 recorded a slump of 32mm and highest compressive strength value of 21.7 N/mm2, among the concrete produced from different forms of gravel.

  15. Ecological Effects of Re-introduction of Salmonid Spawning Gravel in Lowland Danish Streams

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge; Kristensen, Esben Astrup; Kronvang, Brian

    2009-01-01

    recently been conducted in many streams and rivers. However, systematic monitoring of these spawning gravel restoration projects is limited. The overall aim of this paper was to evaluate gravel reintroduction as a long-term salmonid rehabilitation method in 32 lowland streams. Displacement of gravel......, including both restored reaches and upstream control reaches. Downstream displacement of gravel was most common at sites where gravel was reintroduced without further improvement, although these sites exhibited the highest density of YOY brown trout (Salmo trutta), evidencing that the remaining gravel...... is still functional. The intensive study of three streams showed that spawning was enhanced by the introduction of spawning gravel at the restored sites compared to control sites and that habitat quality generally were improved. Our results also suggest complex interactions exist between spawning activity...

  16. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  17. A new approach to define surface/sub-surface transition in gravel beds

    Science.gov (United States)

    Haynes, Heather; Ockelford, Anne-Marie; Vignaga, Elisa; Holmes, William

    2012-12-01

    The vertical structure of river beds varies temporally and spatially in response to hydraulic regime, sediment mobility, grain size distribution and faunal interaction. Implicit are changes to the active layer depth and bed porosity, both critical in describing processes such as armour layer development, surface-subsurface exchange processes and siltation/ sealing. Whilst measurements of the bed surface are increasingly informed by quantitative and spatial measurement techniques (e.g., laser displacement scanning), material opacity has precluded the full 3D bed structure analysis required to accurately define the surface-subsurface transition. To overcome this problem, this paper provides magnetic resonance imaging (MRI) data of vertical bed porosity profiles. Uniform and bimodal (σ g = 2.1) sand-gravel beds are considered following restructuring under sub-threshold flow durations of 60 and 960 minutes. MRI data are compared to traditional 2.5D laser displacement scans and six robust definitions of the surface-subsurface transition are provided; these form the focus of discussion.

  18. Geologie study off gravels of the Agua Fria River, Phoenix, AZ

    Science.gov (United States)

    Langer, W.H.; Dewitt, E.; Adams, D.T.; O'Briens, T.

    2010-01-01

    The annual consumption of sand and gravel aggregate in 2006 in the Phoenix, AZ metropolitan area was about 76 Mt (84 million st) (USGS, 2009), or about 18 t (20 st) per capita. Quaternary alluvial deposits in the modern stream channel of the Agua Fria River west of Phoenix are mined and processed to provide some of this aggregate to the greater Phoenix area. The Agua Fria drainage basin (Fig. 1) is characterized by rugged mountains with high elevations and steep stream gradients in the north, and by broad alluvial filled basins separated by elongated faultblock mountain ranges in the south. The Agua Fria River, the basin’s main drainage, flows south from Prescott, AZ and west of Phoenix to the Gila River. The Waddel Dam impounds Lake Pleasant and greatly limits the flow of the Agua Fria River south of the lake. The southern portion of the watershed, south of Lake Pleasant, opens out into a broad valley where the river flows through urban and agricultural lands to its confluence with the Gila River, a tributary of the Colorado River.

  19. EVALUATION OF THE INITIAL TREE COMMUNITY ESTABBLISHED ON A GRAVEL MINE IN THE BRAZILIAN FEDERAL DISTRICT

    Directory of Open Access Journals (Sweden)

    Raquel Álvares Leão

    2005-05-01

    Full Text Available Mining activities for urbanization purposes have been practiced in the BrazilianFederal District for the last fifty years. Exploitation of sand, clay, stones, calcareous rocks,and gravel deposits resulted in 0.6% of the territory degraded by mining. Deposits explored inthe last ten years have been reclaimed as demanded by local laws.The natural restoration of areas degraded by mining explotation is unpraticable,because the seed-bed and seedlings-bed is very injuried. Also the superficial layers of soil aretaken off, causing loss of microorganism like fungi, which contributes for environmental’squality improvement for the vegetation reestablishment (Vargas & Hungria, 1997.Fortunatelly, environmental laws oblige miners to replace these superficial layers of soil(CREA-DF Cursos, 2004.The recovering of a degradaded area doesn’t necessarily mean restoration. Restorationonly happens when the damage is minimal, for example, a glade opened by the death of a tree(Fonseca et al., 2001. When an area is hardly damaged, the vegetal climax community,resulting from secondary succession, will never be the same as the one standed there before(CREA-DF Cursos, 2004; Fonseca et al., 2001. In the case of areas degraded by mining,human intervention is necessary, because the vegetation has lost its resilience, and is not ableto commence a secondary succession by itself.

  20. Identification of discontinuous sand pulses on the bed of the Colorado River in Grand Canyon

    Science.gov (United States)

    Mueller, E. R.; Grams, P. E.; Buscombe, D.; Topping, D. J.

    2017-12-01

    Decades of research on alluvial sandbars and sand transport on the Colorado River in Grand Canyon has contributed to in-depth understanding of the sand budget and lead to management actions designed to rebuild eroded sandbars. However, some basic, but difficult to address, questions about the processes and rates of sand movement through the system still limit our ability to predict geomorphic responses. The coarse fraction of the bed is heterogeneous and varies among boulders, cobble, gravel, and bedrock. Sand covers these substrates in patches of variable size and thickness, fills interstices to varying degrees, and forms mixed sand/coarse bed configurations such as linear stripes. Understanding the locations of sand accumulation, the quantities of sand contained in those locations, and the processes by which sand is exchanged among depositional locations is needed to predict the morphological response of sandbars to management actions, such as the controlled flood releases, and to predict whether sandbars are likely to increase or decrease in size over long (i.e. decadal) time periods. Here, we present evidence for the downstream translation of the sand component of tributary sediment inputs as discontinuous sand pulses. The silt and clay (mud) fraction of sediment introduced episodically by seasonal floods from tributary streams is transported entirely in suspension and moves through the 400 km series of canyons in a few days. The sand fraction of this sediment, which is transported on the bed and in suspension, moves downstream in sand pulses that we estimate range in length from a few km to tens of km. Owing to the complex geomorphic organization, the sand pulses are not detectable as coherent bed features; each individual sand pulse is comprised of many isolated storage locations, separated by rapids and riffles where sand cover is sparse. The presence of the sand pulses is inferred by the existence of alternating segments of sand accumulation and depletion

  1. Test of Gravel to South Leg - Siri Platform

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo

    A grout connection between one of the legs of the offshore platform, Siri, and a water caisson at the seabed is failed. The failure leaves a gap in the grout connection meaning that the stiffness of the connection is disappeared resulting in movements of the platform. These movements cause cracks...... in the caisson, hence, the stiffness of the connection must be re-established. In this report the effect of filling a sand material into the gap in the grout connection is investigated. Four types of sand materials is tested; Sand 0-8 mm, Norit 0-2 mm, Norit 0-5 mm, and Sand 0.4-5.6 mm. The comparison...

  2. Oil sands tax expenditures

    International Nuclear Information System (INIS)

    Ketchum, K; Lavigne, R.; Plummer, R.

    2001-01-01

    The oil sands are a strategic Canadian resource for which federal and provincial governments provide financial incentives to develop and exploit. This report describes the Oil Sands Tax Expenditure Model (OSTEM) developed to estimate the size of the federal income tax expenditure attributed to the oil sands industry. Tax expenditures are tax concessions which are used as alternatives to direct government spending for achieving government policy objectives. The OSTEM was developed within the business Income Tax Division of Canada's Department of Finance. Data inputs for the model were obtained from oil sands developers and Natural Resources Canada. OSTEM calculates annual revenues, royalties and federal taxes at project levels using project-level projections of capital investment, operating expenses and production. OSTEM calculates tax expenditures by comparing taxes paid under different tax regimes. The model also estimates the foregone revenue as a percentage of capital investment. Total tax expenditures associated with investment in the oil sands are projected to total $820 million for the period from 1986 to 2030, representing 4.6 per cent of the total investment. 10 refs., 2 tabs., 7 figs

  3. Bituminous sands : tax issues

    International Nuclear Information System (INIS)

    Patel, B.

    2004-01-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs

  4. Gravel sediment routing from widespread, low-intensity landscape disturbance, Current River basin, Missouri

    Science.gov (United States)

    Jacobson, Robert B.; Gran, K.B.

    1999-01-01

    During the last 160 years, land-use changes in the Ozarks have had the potential to cause widespread, low-intensity delivery of excess amounts of gravel-sized sediment to stream channels. Previous studies have indicated that this excess gravel bedload is moving in wave-like forms through Ozarks drainage basins. The longitudinal, areal distribution of gravel bars along 160 km of the Current River, Missouri, was evaluated to determine the relative effects of valley-scale controls, tributary basin characteristics, and lagged sediment transport in creating areas of gravel accumulations. The longitudinal distribution of gravel-bar area shows a broad scale wave-like form with increases in gravel-bar area weakly associated with tributary junctions. Secondary peaks of gravel area with 1·8–4·1 km spacing (disturbance reaches) are superimposed on the broad form. Variations in valley width explain some, but not all, of the short-spacing variation in gravel-bar area. Among variables describing tributary drainage basin morphometry, present-day land use and geologic characteristics, only drainage area and road density relate even weakly to gravel-bar areal inventories. A simple, channel network-based sediment routing model shows that many of the features of the observed longitudinal gravel distribution can be replicated by uniform transport of sediment from widespread disturbances through a channel network. These results indicate that lagged sediment transport may have a dominant effect on the synoptic spatial distribution of gravel in Ozarks streams; present-day land uses are only weakly associated with present-day gravel inventories; and valley-scale characteristics have secondary controls on gravel accumulations in disturbance reaches.

  5. Transient electromagnetic soundings in the San Luis Valley, Colorado, near the Great Sand Dunes National Park and Preserve and the Alamosa National Wildlife Refuge (field seasons 2007, 2009, and 2011)

    Science.gov (United States)

    Fitterman, David V.

    2017-06-13

    Transient electromagnetic (TEM) soundings were made in the San Luis Valley, Colorado, to map the location of a blue clay unit as well as to investigate the presence of suspected faults. A total of 147 soundings were made near and in Great Sand Dunes National Park and Preserve, and an additional 6 soundings were made near Hansen Bluff on the eastern edge of the Alamosa National Wildlife Refuge. The blue clay is a significant hydrologic feature in the area that separates an unconfined surface aquifer from a deeper confined aquifer. Knowledge of its location is important to regional hydrological models. Previous analysis of well logs has shown that the blue clay has a resistivity of 10 ohm-meters or less, which is in contrast to the higher resistivity of sand, gravel, and other clay units found in the area, making it a very good target for TEM soundings. The top of the blue clay was found to have considerable relief, suggesting the possibility of deformation of the clay during or after deposition. Because of rift activity, deformation is to be expected. Of the TEM profiles made across faults identified by aeromagnetic data, some showed resistivity variations and (or) subsurface elevation relief of resistivity units, suggestive of faulting. Such patterns were not associated with all suspected faults. The Hansen Bluff profile showed variations in resistivity and depth to conductor that coincide with a scarp between the highlands to the east and the floodplain of the Rio Grande to the west.

  6. Generalized hydrogeologic framework and groundwater budget for a groundwater availability study for the glacial aquifer system of the United States

    Science.gov (United States)

    Reeves, Howard W.; Bayless, E. Randall; Dudley, Robert W.; Feinstein, Daniel T.; Fienen, Michael N.; Hoard, Christopher J.; Hodgkins, Glenn A.; Qi, Sharon L.; Roth, Jason L.; Trost, Jared J.

    2017-12-14

    The glacial aquifer system groundwater availability study seeks to quantify (1) the status of groundwater resources in the glacial aquifer system, (2) how these resources have changed over time, and (3) likely system response to future changes in anthropogenic and environmental conditions. The glacial aquifer system extends from Maine to Alaska, although the focus of this report is the part of the system in the conterminous United States east of the Rocky Mountains. The glacial sand and gravel principal aquifer is the largest source of public and self-supplied industrial supply for any principal aquifer and also is an important source for irrigation supply. Despite its importance for water supply, water levels in the glacial aquifer system are generally stable varying with climate and only locally from pumping. The hydrogeologic framework developed for this study includes the information from waterwell records and classification of material types from surficial geologic maps into likely aquifers dominated by sand and gravel deposits. Generalized groundwater budgets across the study area highlight the variation in recharge and discharge primarily driven by climate.

  7. Provenance and recycling of Arabian desert sand

    Science.gov (United States)

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

    2013-05-01

    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

  8. Sand Dunes with Frost

    Science.gov (United States)

    2004-01-01

    9 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of frost-covered sand dunes in the north polar region of Mars in early spring, 2004. The dunes indicate wind transport of sand from left to right (west to east). These landforms are located near 78.1oN, 220.8oW. This picture is illuminated by sunlight from the lower left and covers an area about 3 km (1.9 mi) across.

  9. Particulate removal processes and hydraulics of porous gravel media filters

    Science.gov (United States)

    Minto, J. M.; Phoenix, V. R.; Dorea, C. C.; Haynes, H.; Sloan, W. T.

    2013-12-01

    Sustainable urban Drainage Systems (SuDS) are rapidly gaining acceptance as a low-cost tool for treating urban runoff pollutants close to source. Road runoff water in particular requires treatment due to the presence of high levels of suspended particles and heavy metals adsorbed to these particles. The aim of this research is to elucidate the particle removal processes that occur within gravel filters that have so far been considered as 'black-box' systems. Based on these findings, a better understanding will be attained on what influences gravel filter removal efficiency and how this changes throughout their design life; leading to a more rational design of this useful technology. This has been achieved by tying together three disparate research elements: tracer residence time distribution curves of filters during clogging; 3D magnetic resonance imaging (MRI) of clogging filters and computational fluid dynamics (CFD) modelling of complex filter pore networks. This research relates column average changes in particle removal efficiency and tracer residence time distributions (RTDs) due to clogging with non-invasive measurement of the spatial variability in particle deposition. The CFD modelling provides a link between observed deposition patterns, flow velocities and wall shear stresses as well as the explanations for the change in RTD with clogging and the effect on particle transport. Results show that, as a filter clogs, particles take a longer, more tortuous path through the filter. This is offset by a reduction in filter volume resulting in higher flow velocities and more rapid particle transport. Higher velocities result in higher shear stresses and the development of preferential pathways in which the velocity exceeds the deposition threshold and the overall efficiency of the filter decreases. Initial pore geometry is linked to the pattern of deposition and subsequent formation of preferential pathways. These results shed light on the 'black-box' internal

  10. Sand (CSW4)

    CSIR Research Space (South Africa)

    Estuarine and Coastal Research Unit

    1982-12-01

    Full Text Available This report is one of a series on Cape Estuaries being published under the general title "The Estuaries of the Cape, Part 2". The report provides information on sand estuary: historical background, abiotic and biotic characteristics. It is pointed...

  11. Inland drift sand landscapes

    NARCIS (Netherlands)

    Fanta, J.; Siepel, H.

    2010-01-01

    Man has had a complex relationship with inland drift sands through the ages. For some centuries these landscapes were seen as a threat to society, especially agriculture and housing. At present we conserve these landscapes as important Natura 2000 priority habitats. In this book you may find these

  12. A study on the decontamination of the gravels contaminated by uranium

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ukryang; Kim, Gyenam; Kim, Seungsoo; Moon, Jaikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The amount of gravels contaminated by uranium is usually about 10% of the contaminated soil. Since such contaminated gravels show different kinds and volumes, it would cost a considerable amount of money if they are to be disposed of without going through any special process. Also, there has not been any particular way or technology for processing the gravels contaminated by uranium. Therefore, various fundamental experiments and researches have been carried out for the decontamination of the gravels contaminated by uranium. Through such experiments and researches, it has been possible to obtain some significant results. The acid cleaning process, which is based on the application of the soil cleaning method, can be regarded as one of the major ways used for decontamination. When the gravels contaminated by uranium are cleaned as they are, most of them tend to show an extremely-low level of decontamination. Therefore, it could be said that the inside of each gravel is also contaminated by uranium. As a result, the gravels contaminated by uranium need to be crushed before being cleaned, which would result in a higher level of efficiency for decontamination compared to the previous way. Therefore, it is more effective to crush the subject gravels before cleaning them in terms of decontamination. However, such test results can only be applied to the gravels contaminated by an average level of uranium concentration. Regarding the gravels showing a higher level of uranium concentration than the average, it is still necessary to carry out more researches. Therefore, this study focused on the level of efficiency for decontamination after the contaminated gravels were crushed before being cleaned, in order to find a way to effectively dispose of the gravels contaminated by high-concentration uranium and secure a high level of efficiency for decontamination. In order to decontaminate the gravels which were contained in the soil contaminated by uranium and showed a higher

  13. Gravel Image Segmentation in Noisy Background Based on Partial Entropy Method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Because of wide variation in gray levels and particle dimensions and the presence of many small gravel objects in the background, as well as corrupting the image by noise, it is difficult o segment gravel objects. In this paper, we develop a partial entropy method and succeed to realize gravel objects segmentation. We give entropy principles and fur calculation methods. Moreover, we use minimum entropy error automaticly to select a threshold to segment image. We introduce the filter method using mathematical morphology. The segment experiments are performed by using different window dimensions for a group of gravel image and demonstrates that this method has high segmentation rate and low noise sensitivity.

  14. Water quality in gravel pits in the Bratislava area

    International Nuclear Information System (INIS)

    Flakova, R.; Rohacikova, A.; Zenisova, Z.

    1999-01-01

    The gravel pits around Bratislava have an esthetic, urban and recreational function. Open water table areas are in a direct contact with the air and acquire some characteristics of the surface water. The quality of open water table is much more susceptible to pollution than that of groundwater. Wet and dry deposition, water inflow from the surrounding surface, unmanageable sewerage effluents, solid and liquid wastes, but also the water birds contribute to the pollution. The Department of Hydrogeology has monitored the water quality in six gravel pits (Cunovo, Drazdiak, Strkovec, Pasienky, Zlate Piesky, Vajnory) since 1976 with an an interruption between 1988 - 1993. Two sampling per year have been made since 1994 and after 1998 the analyses have been supplemented by Na, K, Fe, Mn, by oxygen regime parameters, by trace elements (As, Ag, Cd, Co, Cu, Cr, Hg, Ni, Pb, V, Zn) and by organic pollutants. As regards the oxygen regime, the water quality pits is very good. The anthropogenic influence is expressed mainly by the increased contents of sulfates and chlorides. Most problematic trace elements are the mercury and vanadium (Drazdiak, Zlate Piesky and Vajnory). (authors)

  15. Study on HDPE Mixed with Sand as Backfilled Material on Retaining Structure

    Science.gov (United States)

    Talib, Z. A.

    2018-04-01

    The failure of the retaining wall is closely related to backfill material. Granular soils such as sand and gravel are most suitable backfill material because of its drainage properties. However two basic materials are quite heavy and contribute high amount of lateral loads. This study was to determine the effectiveness High Density Polyethylene (HDPE) as a backfill material. HDPE has a lighter weight compare to the sand. It makes HDPE has potential to be used as backfill material. The objective of this study is to identify the most effective percentage of HDPE to replace sand as a backfill material. The percentage of HDPE used in this study was 20%, 30%, 50%, 75% and also 100%. Testing involved in this study were sieve analysis test, constant head permeability test, direct shear test and relative density test. The result shows that the HDPE can be used as backfilled material and save the cost of backfill material

  16. On Pluvial Compaction of Sand

    DEFF Research Database (Denmark)

    Jacobsen, Moust

    At the Institute of Civil Engineering in Aalborg model tests on dry sand specimens have been carried out during the last five years. To reduce deviations in test results, the sand laying technique has been carefully studied, and the sand mass spreader constructed. Preliminary results have been...

  17. Environmental Impacts of Sand Exploitation. Analysis of Sand Market

    Directory of Open Access Journals (Sweden)

    Marius Dan Gavriletea

    2017-06-01

    Full Text Available Sand is an indispensable natural resource for any society. Despite society’s increasing dependence on sand, there are major challenges that this industry needs to deal with: limited sand resources, illegal mining, and environmental impact of sand mining. The purpose of this paper is twofold: to present an overview of the sand market, highlighting the main trends and actors for production, export and import, and to review the main environmental impacts associated with sand exploitation process. Based on these findings, we recommend different measures to be followed to reduce negative impacts. Sand mining should be done in a way that limits environmental damage during exploitation and restores the land after mining operations are completed.

  18. Gravel road stabilisation of Ehnsjoevaegen, Hallstavik[Using fly ash]; Skogsbilvaegsrenovering av Ehnsjoevaegen, Hallstavik

    Energy Technology Data Exchange (ETDEWEB)

    Macsik, Josef; Svedberg, Bo [Ecoloop, Stockholm (Sweden)

    2006-03-15

    Fly ash in geotechnical applications has stabilising, isolating, low permeability and hardening effect. Fly ash can be used in road constructions with low bearing capacity, as well as on top cover material on landfills. The aim of the project was to build a road section with fly ash stabilised gravel, based on laboratory studies, and follow up technical and environmental aspect during the first year after stabilisation. The overall aim of this project was to evaluate fly ash from Holmen Paper, Hallstavik, from technical and environmental point of view in a gravel road construction. A gravel road, Ehnsjoevaegen, was stabilised with fly ash during autumn 2004. This road was a low priority road. The fly ash stabilised road section was 1300 m long. Gravel from the road Ehnsjoevaegen was stabilised and investigated in a laboratory study. Leachability of metals and geotechnical aspects were investigated. The laboratory study showed that fly ash stabilised gravel has high shear strength, however its thawing resistance is not fully acceptable. Additives of cement or merit are needed in order to increase its thawing resistance. The actual road section is not going to be used during thawing period and no additives were used. The test road is divided into different sections including a reference section. The road stabilisation work was conducted with gravel transported to Ehnsjoevaegen from off site and not with gravel from the site. Fly ash was tipped off on a levelled road, followed by tipping of gravel. Mixing fly ash and gravel was done on site by a road scraper. After the mixing the road was gravelled with 0,1 m graded gravel. In this project the fly ash had low water content. In order to get optimal compaction water was added from a tanker supplying water before compacted with a compactor. Results from the pilot test shows that fly ash stabilised gravel can be tipped, mixed and compacted effectively. Tipping can be optimised if fly ash and gravel is mixed in a mixer

  19. Oil sands supply outlook

    International Nuclear Information System (INIS)

    Dunbar, R.

    2004-01-01

    In March 2004, The Canadian Energy Research Institute released a report on the expected future supply from Alberta's oil sands. The report indicates that the future for the already well-established oil sands industry is promising, particularly given the outlook for oil prices. The challenges facing the industry include higher industry supply costs and the need for innovative commercial and technological solutions to address the risks of irregularities and changes in crude oil prices. In 2003, the industry produced 874 thousand barrels per day of synthetic crude oil and unprocessed crude bitumen. This represents 35 per cent of Canada's total oil production. Current production capacity has increased to 1.0 million barrels per day (mbpd) due to new projects. This number may increase to 3.5 mbpd by 2017. Some new projects may be deferred due to the higher raw bitumen and synthetic crude oil supply costs. This presentation provided supply costs for a range of oil sands recovery technologies and production projections under various business scenarios. tabs., figs

  20. Liquefaction resistance of calcareous sands

    International Nuclear Information System (INIS)

    Sandoval Vallejo, Eimar

    2012-01-01

    Calcareous sands are unique in terms of their origin, mineralogy, shape, fragility and intra particle porosity. This article presents results from an experimental program carried out to study the liquefaction resistance of a calcareous sand retrieved from Cabo Rojo at Puerto Rico. The experimental program included mineralogical characterization, index properties, and undrained cyclic triaxial tests on isotropically consolidated reconstituted samples. Due to the large variation in the calcareous sand properties, results are compared with previous researches carried out on other calcareous sands around the world. Results showed a wide range in the liquefaction resistance of the studied calcareous sands. Cabo Rojo sand experienced greater liquefaction resistance than most of the calcareous sands used for comparison. Important differences in the excess pore pressure generation characteristics were also found.

  1. Ecology and demographics of Pacific sand lance, Ammodytes hexapterus Pallas, in Lower Cook Inlet, Alaska

    Science.gov (United States)

    Robards, Martin D.; Piatt, John F.

    2000-01-01

    Distinct sand lance populations occur within the relatively small geographic area of Lower Cook Inlet, Alaska. Marked meso-scale differences in abundance, growth, and mortality exist as a consequence of differing oceanographic regimes. Growth rate within populations (between years) was positively correlated with temperature. However, this did not extend to inter-population comparisons where differing growth rates were better correlated to marine productivity. Most sand lance reached maturity in their second year. Field observations and indices of maturity, gonad development, and ova-size distribution all indicated that sand lance spawn once each year. Sand lance spawned intertidally in late September and October on fine gravel/sandy beaches. Embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures. Mean dry-weight energy value of sand lance cycles seasonally, peaking in spring and early summer (20.91 kJg-1 for males, 21.08 kJg-1 for females), and subsequently declining by about 25% during late summer and fall (15.91 kJg-1 for males, 15.74 kJg-1 for females). Sand lance enter the winter with close to their minimum whole body energy content. Dry weight energy densities of juveniles increased from a minimum 16.67 kJg-1 to a maximum of 19.68 kJg-1 and are higher than adults in late summer.

  2. The effect of coarse gravel on cohesive sediment entrapment in an annular flume

    Science.gov (United States)

    Glasbergen, K.; Stone, M.; Krishnappan, B.; Dixon, J.; Silins, U.

    2015-03-01

    While cohesive sediment generally represents a small fraction (armour layer of the gravel bed (>16 Pa), cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

  3. Sea Dredged Gravel versus Crushed Granite as Coarse Aggregate for Self Compacting Concrete in Aggressive Environment

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.; Kristensen, Lasse Frølich

    2007-01-01

    Properties of self compacting concrete (SCC) with two types of coarse aggregate - sea dredged gravel with smooth and rounded particles and crushed granite with rough and angular particles - have been studied. Sea gravel allowed a higher aggregate proportion in the concrete leading to a higher...

  4. Evaluation of an ion adsorption method to estimate intragravel flow velocity in salmonid spawning gravels

    Science.gov (United States)

    James L. Clayton; John G. King; Russell F. Thurow

    1996-01-01

    Intragravel water exchange provides oxygenated water, removes metabolic waste, and is an essential factor in salmonid embryo survival. Measurements of intragravel flow velocity have been suggested as an index of gravel quality and also as a useful predictor of fry emergence; however, proposed methods for measuring velocity in gravel are problematic. We evaluate an ion...

  5. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  6. Sediment Source Fingerprinting of the Lake Urmia Sand Dunes.

    Science.gov (United States)

    Ahmady-Birgani, Hesam; Agahi, Edris; Ahmadi, Seyed Javad; Erfanian, Mahdi

    2018-01-09

    Aeolian sand dunes are continuously being discovered in inner dry lands and coastal areas, most of which have been formed over the Last Glacial Maximum. Presently, due to some natural and anthropogenic implications on earth, newly-born sand dunes are quickly emerging. Lake Urmia, the world's second largest permanent hypersaline lake, has started shrinking, vast lands comprising sand dunes over the western shore of the lake have appeared and one question has been playing on the minds of nearby dwellers: where are these sand dunes coming from, What there was not 15 years ago!! In the present study, the determination of the source of the Lake Urmia sand dunes in terms of the quantifying relative contribution of each upstream geomorphological/lithological unit has been performed using geochemical fingerprinting techniques. The findings demonstrate that the alluvial and the fluvial sediments of the western upstream catchment have been transported by water erosion and they accumulated in the lower reaches of the Kahriz River. Wind erosion, as a secondary agent, have carried the aeolian sand-sized sediments to the sand dune area. Hence, the Lake Urmia sand dunes have been originating from simultaneous and joint actions of alluvial, fluvial and aeolian processes.

  7. The air flow and heat transfer in gravel embankment in permafrost areas

    Institute of Scientific and Technical Information of China (English)

    JIANG Fan; LIU Shi; WANG Haigang; CHEN Huanzhuo

    2004-01-01

    A comparative numerical investigation of transient temperature profile and pore-air velocities in horizontal rock block embankments are conducted using the "gravels model", in which the embankment is composed of stones and air, and the "porous media model" respectively. As the velocities from the "gravels model" directly reflect the true flow of air and winter-time convection, in this paper it can be concluded that computational results from the "gravels model"are superior to the "porous media model". In addition, the "gravels model" has the advantages of reflecting the effect of the dimensions and collocation of gravels upon the temperature fields.Therefore, the computation of the gravels embankment is mainly based on the gravels model.Simulation results show that in summer, a clockwise circulation of the pore-air extends throughout most of the embankment. However its motion is very weak that results in relatively straight horizontal isotherm lines. And heat transfer is mainly maintained through conduction. But in winter, the pore-air velocities are higher and multiple vortexes are formed in the embankment.Natural convection then becomes the dominant influence on the isotherm shapes within the embankment. The isotherms are complex and alternative upward and downward flowing plumes exist. The winter-time convection can further reduce the temperature of the foundation soil beneath the gravel embankment. In addition, the effects of the gravel dimensions within the embankment have been analyzed and compared in the gravels model. It shows that in winter, large stones, e.g. 200 mm, lead to stronger vortexes than those of small stones, say 60 mm. Consequently, the zone of low-temperature beneath the large-stone embankment extends deeper into the ground.

  8. Revegetation and management of tailings sand slopes from tar sand extraction: 1978 results

    Energy Technology Data Exchange (ETDEWEB)

    Rowell, M J

    1979-01-01

    The results are reported of research into the revegetation of two areas on a steeply sloping dike composed of tailings sand from tar sand extraction at the Great Canadian Oil Sand Limited plant at Fort McMurray, Alberta. One area was seeded with three pasture grasses and two legumes in 1971 after the slope surface had been mixed with peat to a depth of 15 cm. A second area had been amended with peat or peat and overburden and differing rates of fertilizer added. A mix containing nine grasses, four legumes, and oats, as a companion crop, was seeded in July 1976. The objectives of the research were to study methods for the establishment of a stable vegetative cover that would prevent erosion of the slope and, in time, might become a self maintaining unit. Tillage of soil amendments to a depth of 15 cm and 30 cm were compared in promoting deeper rooting and stabilizing of the slope.

  9. Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer

    Science.gov (United States)

    Smith, Richard L.; Kent, Douglas B.; Repert, Deborah A.; Böhlke, J.K.

    2017-01-01

    Nitrate has become an increasingly abundant potential electron acceptor for Fe(II) oxidation in groundwater, but this redox couple has not been well characterized within aquifer settings. To investigate this reaction and some of its implications for redox-sensitive groundwater contaminants, we conducted an in situ field study in a wastewater-contaminated aquifer on Cape Cod. Long-term (15 year) geochemical monitoring within the contaminant plume indicated interacting zones with variable nitrate-, Fe(II)-, phosphate-, As(V)-, and As(III)-containing groundwater. Nitrate and phosphate were derived predominantly from wastewater disposal, whereas Fe(II), As(III), and As(V) were mobilized from the aquifer sediments. Multiple natural gradient, anoxic tracer tests were conducted in which nitrate and bromide were injected into nitrate-free, Fe(II)-containing groundwater. Prior to injection, aqueous Fe(II) concentrations were approximately 175 μM, but sorbed Fe(II) accounted for greater than 90% of the total reactive Fe(II) in the aquifer. Nitrate reduction was stimulated within 1 m of transport for 100 μM and 1000 μM nitrate additions, initially producing stoichiometric quantities of nitrous oxide (>300 μM N). In subsequent injections at the same site, nitrate was reduced even more rapidly and produced less nitrous oxide, especially over longer transport distances. Fe(II) and nitrate concentrations decreased together and were accompanied by Fe(III) oxyhydroxide precipitation and decreases in dissolved phosphate, As(III), and As(V) concentrations. Nitrate N and O isotope fractionation effects during nitrate reduction were approximately equal (ε15N/ε18O = 1.11) and were similar to those reported for laboratory studies of biological nitrate reduction, including denitrification, but unlike some reported effects on nitrate by denitrification in aquifers. All constituents affected by the in situ tracer experiments returned to pre-injection levels after several weeks. Additionally, Fe(II)-oxidizing, nitrate-reducing microbial enrichment cultures were obtained from aquifer sediments. Growth experiments with the cultures sequentially produced nitrite and nitrous oxide from nitrate while simultaneously oxidizing Fe(II). Field and culture results suggest that nitrogen oxide reduction and Fe(II) oxidation in the aquifer are a complex interaction of coupled biotic and abiotic reactions. Overall, the results of this study demonstrate that anoxic nitrate-dependent iron oxidation can occur in groundwater; that it could control iron speciation; and that the process can impact the mobility of other chemical species (e.g., phosphate and arsenic) not directly involved in the oxidation–reduction reaction.

  10. Oil sands development update

    International Nuclear Information System (INIS)

    1999-01-01

    A detailed review and update of oil sands development in Alberta are provided covering every aspect of the production and economic aspects of the industry. It is pointed out that at present oil sands account for 28 per cent of Canadian crude oil production, expected to reach 50 per cent by 2005. Based on recent announcements, a total of 26 billion dollars worth of projects are in progress or planned; 20 billion dollars worth of this development is in the Athabasca area, the remainder in Cold Lake and other areas. The current update envisages up to 1,800,000 barrels per day by 2008, creating 47,000 new jobs and total government revenues through direct and indirect taxes of 118 billion dollars. Provinces other than Alberta also benefit from these development, since 60 per cent of all employment and income created by oil sands production is in other parts of Canada. Up to 60 per cent of the expansion is for goods and services and of this, 50 to 55 per cent will be purchased from Canadian sources. The remaining 40 per cent of the new investment is for engineering and construction of which 95 per cent is Canadian content. Aboriginal workforce by common consent of existing operators matches regional representation (about 13 per cent), and new developers are expected to match these standards. Planned or ongoing development in environmental protection through improved technologies and optimization, energy efficiency and improved tailings management, and active support of flexibility mechanisms such as emission credits trading, joint implementation and carbon sinks are very high on the industry's agenda. The importance of offsets are discussed extensively along with key considerations for international negotiations, as well as further research of other options such as sequestration, environmentally benign disposal of waste, and enhanced voluntary action

  11. XBeach-G: a tool for predicting gravel barrier response to extreme storm conditions

    Science.gov (United States)

    Masselink, Gerd; Poate, Tim; McCall, Robert; Roelvink, Dano; Russell, Paul; Davidson, Mark

    2014-05-01

    Gravel beaches protect low-lying back-barrier regions from flooding during storm events and their importance to society is widely acknowledged. Unfortunately, breaching and extensive storm damage has occurred at many gravel sites and this is likely to increase as a result of sea-level rise and enhanced storminess due to climate change. Limited scientific guidance is currently available to provide beach managers with operational management tools to predict the response of gravel beaches to storms. The New Understanding and Prediction of Storm Impacts on Gravel beaches (NUPSIG) project aims to improve our understanding of storm impacts on gravel coastal environments and to develop a predictive capability by modelling these impacts. The NUPSIG project uses a 5-pronged approach to address its aim: (1) analyse hydrodynamic data collected during a proto-type laboratory experiment on a gravel beach; (2) collect hydrodynamic field data on a gravel beach under a range of conditions, including storm waves with wave heights up to 3 m; (3) measure swash dynamics and beach response on 10 gravel beaches during extreme wave conditions with wave heights in excess of 3 m; (4) use the data collected under 1-3 to develop and validate a numerical model to model hydrodynamics and morphological response of gravel beaches under storm conditions; and (5) develop a tool for end-users, based on the model formulated under (4), for predicting storm response of gravel beaches and barriers. The aim of this presentation is to present the key results of the NUPSIG project and introduce the end-user tool for predicting storm response on gravel beaches. The model is based on the numerical model XBeach, and different forcing scenarios (wave and tides), barrier configurations (dimensions) and sediment characteristics are easily uploaded for model simulations using a Graphics User Interface (GUI). The model can be used to determine the vulnerability of gravel barriers to storm events, but can also be

  12. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  13. PGDP Trichloroethene Biodegradation Investigation Summary Report: Regional Gravel Aquifer & Northwest Plume

    Energy Technology Data Exchange (ETDEWEB)

    Hampson, Steve [Univ. of Kentucky, Lexington, KY (United States). Kentucky Research Consortium for Energy and Environment

    2008-09-01

    The evaluation of biological degradation processes addressed by this report are part of a broad trichloroethene (TCE) Fate and Transport Investigation that includes four (4) topics of phased investigation (Table ES1) relative to degradation and/or attenuation of TCE in the Regional Gravel Aquifer (RGA) underlying the United States Department of Energy Paducah Gaseous Diffusion Plant (PGDP). In order of implementation the project phases are: (1) derivation of a TCE first-order rate constant by normalization of TCE values against technetium-99 (99Tc) and chloride. 2) identification of the presence of microbes capable of aerobic co-metabolic TCE biodegradation using enzyme activity probes (this report); 3) Compound-specific isotope analysis (CSIA) to support prevalence of biotic and/or abiotic degradation processes; and 4) evaluation of potential abiotic RGA-TCE attenuation mechanisms including sorption. This report summarizes the Phase II activities related to the identification and evaluation of biological degradation processes that may be actively influencing TCE fate and transport in the RGA contaminant plumes at the United States Department of Energy (DOE) PGDP and its environs (Figure ES1). The goals of these activities were to identify active biological degradation mechanisms in the RGA through multiple lines of evidence and to provide DOE with recommendations for future TCE biological degradation investigations.

  14. Delineation of gravel-bed clusters via factorial kriging

    Science.gov (United States)

    Wu, Fu-Chun; Wang, Chi-Kuei; Huang, Guo-Hao

    2018-05-01

    Gravel-bed clusters are the most prevalent microforms that affect local flows and sediment transport. A growing consensus is that the practice of cluster delineation should be based primarily on bed topography rather than grain sizes. Here we present a novel approach for cluster delineation using patch-scale high-resolution digital elevation models (DEMs). We use a geostatistical interpolation method, i.e., factorial kriging, to decompose the short- and long-range (grain- and microform-scale) DEMs. The required parameters are determined directly from the scales of the nested variograms. The short-range DEM exhibits a flat bed topography, yet individual grains are sharply outlined, making the short-range DEM a useful aid for grain segmentation. The long-range DEM exhibits a smoother topography than the original full DEM, yet groupings of particles emerge as small-scale bedforms, making the contour percentile levels of the long-range DEM a useful tool for cluster identification. Individual clusters are delineated using the segmented grains and identified clusters via a range of contour percentile levels. Our results reveal that the density and total area of delineated clusters decrease with increasing contour percentile level, while the mean grain size of clusters and average size of anchor clast (i.e., the largest particle in a cluster) increase with the contour percentile level. These results support the interpretation that larger particles group as clusters and protrude higher above the bed than other smaller grains. A striking feature of the delineated clusters is that anchor clasts are invariably greater than the D90 of the grain sizes even though a threshold anchor size was not adopted herein. The average areal fractal dimensions (Hausdorff-Besicovich dimensions of the projected areas) of individual clusters, however, demonstrate that clusters delineated with different contour percentile levels exhibit similar planform morphologies. Comparisons with a

  15. Dark grains of sand: a geological storytelling

    Science.gov (United States)

    Gallo Maresca, Magda

    2017-04-01

    In the secondary Italian school the Earth science learning begins at first year, in synergy with other natural science subjects such as Astronomy, Chemistry and Biology. Italian teachers have to focus on the landscape geomorphological aspects and often Earth processes are difficult to display since they are related to certain phenomena happened during the past and often far from the involved country. In order to better understand the environment surrounding us, very simple and poor materials, like sands, allow the teachers to create attractive lab experiences. According to the IBSE (Inquiry Based Science Education) approach, a learning unit has been implemented starting from a walking along the light carbonate beaches of the Adriatic sea: a smart look to the sands ("engage step"), stroke the students fantasy pushing them to explore some strange black grains on the sands. Dirty sands? Or rock landscape, soil degradation and Ofanto river and coastal processes (erosion, transportation and deposition)? This was the teaching challenge. Due to the youngest age, a third level, guided inquiry, was adopted so the teacher is the "guide of inquiry" encouraging the students using the research question ("Why is the sand dark?", "Do all sands look the same?", "Where does it come from?") and driving the students around their investigation plans ("How can I measure grain size?"). A procedure to answer the above questions and validate the results and explanations has been implemented to allow the students to be proactive in their study. During the learning activities will be the students to ask for field trip to elaborate their new knowledge, verify and visualize the speculated processes. The teaching skills allow to address several geosciences domains such as mineralogy, petrology, regional geology and geodynamics as well as other scientific disciplines such as mathematics (more specifically statistics), forensic science and even life sciences (the presence of bioclasts might

  16. Rheological Characterization of Green Sand Flow

    DEFF Research Database (Denmark)

    Jabbaribehnam, Mirmasoud; Spangenberg, Jon; Hovad, Emil

    2016-01-01

    The main aim of this paper is to characterize experimentally the flow behaviour of the green sand that is used for casting of sand moulds. After the sand casting process is performed, the sand moulds are used for metal castings. The rheological properties of the green sand is important to quantif...

  17. Roughness coefficient and its uncertainty in gravel-bed river

    Directory of Open Access Journals (Sweden)

    Ji-Sung Kim

    2010-06-01

    Full Text Available Manning's roughness coefficient was estimated for a gravel-bed river reach using field measurements of water level and discharge, and the applicability of various methods used for estimation of the roughness coefficient was evaluated. Results show that the roughness coefficient tends to decrease with increasing discharge and water depth, and over a certain range it appears to remain constant. Comparison of roughness coefficients calculated by field measurement data with those estimated by other methods shows that, although the field-measured values provide approximate roughness coefficients for relatively large discharge, there seems to be rather high uncertainty due to the difference in resultant values. For this reason, uncertainty related to the roughness coefficient was analyzed in terms of change in computed variables. On average, a 20% increase of the roughness coefficient causes a 7% increase in the water depth and an 8% decrease in velocity, but there may be about a 15% increase in the water depth and an equivalent decrease in velocity for certain cross-sections in the study reach. Finally, the validity of estimated roughness coefficient based on field measurements was examined. A 10% error in discharge measurement may lead to more than 10% uncertainty in roughness coefficient estimation, but corresponding uncertainty in computed water depth and velocity is reduced to approximately 5%. Conversely, the necessity for roughness coefficient estimation by field measurement is confirmed.

  18. Maturation, fecundity, and intertidal spawning of Pacific sand lance in the northern Gulf of Alaska

    Science.gov (United States)

    Robards, Martin D.; Piatt, John F.; Rose, G.A.

    1999-01-01

    Pacific sand lance Ammodytes hexapterus in Kachemak Bay, Alaska, showed no sexual dimorphism in length-to-weight (gonad-free) ratio or length-at-age relationship. Most matured in their second year, males earlier in the season than females, but females (31%) attained a higher gonadosomatic index than males (21%). Sand lance spawned intertidally once each year in late September and October on fine gravel or sandy beaches soon after the seasonal peak in water temperatures. Sand lance in Cook Inlet and Prince William Sound displayed similar maturation schedules. Schools were dominated 2: 1 by males as they approached the intertidal zone at a site where spawning has taken place for decades. Sand lance spawned vigorously in dense formations, leaving scoured pits in beach sediments. Fecundity of females (93–199 mm) was proportional to length, ranging from 1468 to 16 081 ova per female. About half of the overall spawning school fecundity was derived from age group 1 females (55% of the school by number). Spawned eggs were 1·02 mm in diameter, demersal, slightly adhesive, and deposited in the intertidal just below the waterline. Sand lance embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures.

  19. Sand, jams and jets

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, H. [James Franck Institute and Department of Physics, University of Chicago (United States)]. E-mail: h-jaeger@uchicago.edu

    2005-12-01

    Granular media are offering new insights into problems in condensed-matter physics and materials science, as Heinrich Jaeger explains. The remarkable properties of granular materials are so familiar that most of us do not even notice them. It is clear, for example, that we cannot walk on water unless the temperature has dropped below freezing. However, we take it for granted that sand will support our weight as if it were a solid, even though it can also be poured like a liquid under the same ambient conditions. From breakfast cereal, sugar and flour to construction materials, mining products and pharmaceuticals, granular media are present everywhere in our daily lives. (U.K.)

  20. Characterization of major lithologic units underlying the lower American River using water-borne continuous resistivity profiling, Sacramento, California, June 2008

    Science.gov (United States)

    Ball, Lyndsay B.; Teeple, Andrew

    2013-01-01

    The levee system of the lower American River in Sacramento, California, is situated above a mixed lithology of alluvial deposits that range from clay to gravel. In addition, sand deposits related to hydraulic mining activities underlie the floodplain and are preferentially prone to scour during high-flow events. In contrast, sections of the American River channel have been observed to be scour resistant. In this study, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, explores the resistivity structure of the American River channel to characterize the extent and thickness of lithologic units that may impact the scour potential of the area. Likely lithologic structures are interpreted, but these interpretations are non-unique and cannot be directly related to scour potential. Additional geotechnical data would provide insightful data on the scour potential of certain lithologic units. Additional interpretation of the resistivity data with respect to these results may improve interpretations of lithology and scour potential throughout the American River channel and floodplain. Resistivity data were collected in three profiles along the American River using a water-borne continuous resistivity profiling technique. After processing and modeling these data, inverted resistivity profiles were used to make interpretations about the extent and thickness of possible lithologic units. In general, an intermittent high-resistivity layer likely indicative of sand or gravel deposits extends to a depth of around 30 feet (9 meters) and is underlain by a consistent low-resistivity layer that likely indicates a high-clay content unit that extends below the depth of investigation (60 feet or 18 meters). Immediately upstream of the Watt Avenue Bridge, the high-resistivity layer is absent, and the low-resistivity layer extends to the surface where a scour-resistant layer has been previously observed in the river bed.

  1. Riddle of the sands

    Energy Technology Data Exchange (ETDEWEB)

    Rolheiser, P

    1998-09-01

    A geological model of the Alberta landscape during the period stretching from about 110 million to 100 million years ago during the Cretaceous period when dinosaurs roamed the earth, was sketched. Today, the region contains the Cold Lake oil sands deposit. Imperial Oil began large-scale production at Cold Lake in 1985. The formations within the area are the source of almost half of Imperial Oil`s daily crude oil production and account for one in every 20 barrels of oil produced daily in Canada. The bitumen is produced using cyclic steam stimulation where steam is injected at high pressure into the underground reservoir, fracturing the sandstone and heating the bitumen it holds to thin it so that it can then flow through well bores to the surface. Conventional geological theory suggested that the Cold Lake reservoir was the remains of a prehistoric river delta. In 1994, Imperial Oil established a Cold Lake sequence stratigraphy project to verify this theory. This highly complex project involves volumes of geophysical well-log data from the 2,500 wells at Cold Lake, core samples cut from more than 600 of these wells and microscopic fossilized remains of 100-million-year-old flora extracted from the core samples, and seismic information. The interpreted data helps to create a three-dimensional model of the reservoir`s structure and help define its boundaries. Results have shown that the Cold Lake deposit was created from at least 13 intersecting river beds. Each of the rivers flowed for a few hundred thousand years and deposited sands of varying quality in different layers and patterns. The oil came about 40 million years later after the plant and animal materials containing hydrogen and carbon were broken down by heat and pressure to form oil. 1 fig.

  2. The Alberta oil sands story

    Energy Technology Data Exchange (ETDEWEB)

    1974-01-01

    This report serves as a detailed introduction to the Alberta oil sands and their development. It includes a description of the oil sands deposits, an outline of crude bitumen recovery and upgrading processes, the role of Alberta Energy Company in oil sands development, environmental aspects, manpower requirements for oil sands development, research needs, and further oil sands projects. Presently proven recoverable reserves in the oil sands amount to 26.5 billion bbl of synthetic crude. Production from the Syncrude plant (125,000 bbl/d capacity) is expected to begin in 1977, followed by a Shell Canada operation around 1980. The provincial government will participate in the oil sand industry through its joint venture participation in Syncrude and its 50% share in Alberta Energy Company; the latter company participates in related aspects of the Syncrude project, such as pipelines. The result of Alberta's participation in the industry will mean that, directly or indirectly, the province will realize 60% of the total profits. The job creation potential of oil sands projects is estimated to be extensive, with a direct and indirect work force supported by oil sands activities possibly reaching 180,000 persons by the year 2000. Research needs have been identified, particularly in the area of in-situ thermal recovery technology, and the creation of the Alberta Oil Sands Technology and Research Authority has been authorized in order to meet these needs. Although current reserves are sufficient to support 20-30 synthetic crude plants, a number of factors will limit expansion of the industry. 8 figs., 5 tabs.

  3. Environmental laws for mining activities in Provincia de San Juan (Argentina), gravel mines exploitation

    International Nuclear Information System (INIS)

    Ramirez, M.; Carrascosa, H.

    2007-01-01

    This paper analyses San Juan Province - Argentina prevailing environmental legislation for mining activity and gravel mines. The study focuses the subject from a mining engineering point of view. (author)

  4. [Effects of gravel mulch technology on soil erosion resistance and plant growth of river flinty slope].

    Science.gov (United States)

    Zhu, Wei; Xie, San-Tao; Ruan, Ai-Dong; Bian, Xun-Wen

    2008-03-01

    Aiming at the technical difficulties such as the stability and water balance in the ecological rehabilitation of river flinty slope, a gravel mulch technology was proposed, with the effects of different gravel mulch treatments on the soil anti-erosion capacity, soil water retention property, and plant growth investigated by anti-erosion and pot experiments. The results showed that mulching with the gravels 1.5-2 cm in size could obviously enhance the soil anti-erosion capacity, soil water retention property and plant biomass, but no obvious differences were observed between the mulch thickness of 5 cm and 8 cm. It was indicated that mulching with the gravels 1.5-2 cm in size and 5 cm in thickness was an effective and economical technology for the ecological rehabilitation of river flinty slope.

  5. Influence of vegetation and gravel mesh on the tertiary treatment of wastewater from a cosmetics industry.

    Science.gov (United States)

    Vlyssides, Apostolos G; Mai, Sofia T H; Barampouti, Elli Maria P; Loukakis, Haralampos N

    2009-07-01

    To estimate the influence of gravel mesh (fine and coarse) and vegetation (Phragmites and Arundo) on the efficiency of a reed bed, a pilot plant was included after the wastewater treatment plant of a cosmetic industry treatment system according to a 22 factorial experimental design. The maximum biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total phosphorous (TP) reduction was observed in the reactor, where Phragmites and fine gravel were used. In the reactor with Phragmites and coarse gravel, the maximum total Kjeldahl nitrogen (TKN) and total suspended solids (TSS) reduction was observed. The maximum total solids reduction was measured in the reed bed, which was filled with Arundo and coarse gravel. Conclusively, the treatment of a cosmetic industry's wastewater by reed beds as a tertiary treatment method is quite effective.

  6. Performance of a forced convection solar drier integrated with gravel as heat storage material

    Energy Technology Data Exchange (ETDEWEB)

    Mohanraj, M. [Dr Mahalingam College of Engineering and Technology, Pollachi (India). Dept. of Mechanical Engineering; Chandrasekar, P. [Swinburne Univ. of Technology, Sarawak (Malaysia). School of Engineering Sciences

    2009-07-01

    Sun drying is the most common method used in India to dry agricultural products such as grains, fruits and vegetables. The rate of drying depends on solar radiation, ambient temperature, wind velocity, relative humidity, initial moisture content, type of crops, crop absorptivity and mass product per unit exposed area. However, this method of spreading the crop in a thin layer on the ground has several disadvantages. This paper reported on a study that focused on developing a forced convection solar drier integrated with heat storage materials for drying various agricultural crops. The indirect forced convection solar drier, integrated with gravel as a sensible heat material, was used to dry pineapple slices under conditions similar to those found in Pollachi, India. The performance of the system was discussed along with the drying characteristics, drying rate, and specific moisture extraction rate. The results showed that the moisture content (wet basis) of pineapple was reduced from about 87.5 to 14.5 per cent (equilibrium moisture content) in about 29 hours in the bottom tray and 32 hours in the top tray. The thermal efficiency of the solar air heater was also reviewed. 9 refs., 5 figs.

  7. In situ recovery of oil from Utah tar sand: a summary of tar sand research at the Laramie Energy Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, L.C.; Westhoff, J.D.

    1985-10-01

    This report describes work done by the United States Department of Energy's Laramie Energy Technology Center from 1971 through 1982 to develop technology for future recovery of oil from US tar sands. Work was concentrated on major US tar sand deposits that are found in Utah. Major objectives of the program were as follows: determine the feasibility of in situ recovery methods applied to tar sand deposits; and establish a system for classifying tar sand deposits relative to those characteristics that would affect the design and operation of various in situ recovery processes. Contents of this report include: (1) characterization of Utah tar sand; (2) laboratory extraction studies relative to Utah tar sand in situ methods; (3) geological site evaluation; (4) environmental assessments and water availability; (5) reverse combustion field experiment, TS-1C; (6) a reverse combustion followed by forward combustion field experiment, TS-2C; (7) tar sand permeability enhancement studies; (8) two-well steam injection experiment; (9) in situ steam-flood experiment, TS-1S; (10) design of a tar sand field experiment for air-stream co-injection, TS-4; (11) wastewater treatment and oil analyses; (12) economic evaluation of an in situ tar sand recovery process; and (13) appendix I (extraction studies involving Utah tar sands, surface methods). 70 figs., 68 tabs.

  8. Bedform morphology of salmon spawning areas in a large gravel-bed river

    Energy Technology Data Exchange (ETDEWEB)

    Hanrahan, Timothy P.

    2007-05-01

    While the importance of river channel morphology to salmon spawning habitat is increasingly recognized, quantitative measures of the relationships between channel morphology and habitat use are lacking. Such quantitative measures are necessary as management and regulatory agencies within the Pacific Northwestern region of the USA, and elsewhere, seek to quantify potential spawning habitat and develop recovery goals for declining salmon populations. The objective of this study was to determine if fall Chinook salmon (Oncorhynchus tshawytscha) spawning areas in the Snake River, Idaho, USA, were correlated with specific bed form types at the pool-riffle scale. A bed form differencing technique was used to objectively quantify the longitudinal riverbed profile into four distinct pool-riffle units that were independent of discharge. The vertical location of thalweg points within these units was quantified with a riffle proximity index. Chinook salmon spawning areas were mapped and correlated with the pool-riffle units through the use of cross-tabulation tables. The results indicate that 84% of fall Chinook salmon spawning areas were correlated with riffles (Chi-square=152.1, df=3, p<0.001), with 53% of those areas located on the upstream side of riffle crests. The majority of Snake River fall Chinook salmon spawning occurred at a vertical location within 80% of the nearest riffle crest elevation. The analyses of bed form morphology will assist regional fish mangers in quantifying existing and potential fall Chinook salmon spawning habitat, and will provide a quantitative framework for evaluating general ecological implications of channel morphology in large gravel-bed rivers.

  9. Removal of COD and TSS From Dye Solution Using Sand Filtration and Adsorption

    Directory of Open Access Journals (Sweden)

    Heny Juniar

    2016-11-01

    Full Text Available This research was conducted in order to obtain proper compositions and the standard condition for the simple filtration equipments and optimum operational conditions in adsorption column. The research was carried out by analyzing parameters COD and TSS. The result showed that the process was able to reduced parameters observed from filtration step until the process in adsorptions column. The optimum conditions for sand filter equipment were 10 cm sand height, at least 7 cm fibers, 3-4 cm gravel. In the adsorption column, the optimum conditions for green waste water were flow rate at 40 ml/min 60 min adsorptions time, and 60 cm bed height. While purple for waste water; 20 mL/min of flowrate, 60 min of adsorption time, and the 60 cm of bed height

  10. Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes

    Science.gov (United States)

    Hauer, F. Richard; Locke, Harvey; Dreitz, Victoria; Hebblewhite, Mark; Lowe, Winsor; Muhlfeld, Clint C.; Nelson, Cara; Proctor, Michael F.; Rood, Stewart B.

    2016-01-01

    Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologicaltering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.

  11. The energy efficiency of oil sands extraction: Energy return ratios from 1970 to 2010

    International Nuclear Information System (INIS)

    Brandt, Adam R.; Englander, Jacob; Bharadwaj, Sharad

    2013-01-01

    It has been argued that the oil sands industry is not energy efficient: comparatively large energy inputs are required per unit of energy output from oil sands operations. Unfortunately, quantitative work to date in this area has suffered from poor data availability and uncertain methods. We apply a new methodology and new dataset to compute ERRs (energy return ratios) for the oil sands industry. We collected monthly oil sands energy consumption and output data from 1970 to 2010. Current oil sands operations have mine mouth NERs (net energy returns) of about 6 GJ output per GJ of energy consumed and point of use energy returns of about 3 GJ/GJ. Long-term trends show oil sands operations becoming significantly more efficient: point of use NER increased from about 1 GJ/GJ in 1970 to 3 GJ/GJ in 2010. These energy returns are lower than those observed in historical conventional oil operations, but low energy returns are not likely to hinder development of oil sands operations due to the large resource in place and the ability for largely self-fueled pathways to return significant amounts of energy to society for every unit of external energy supplied. - Highlights: • Oil sands operations have become significantly more energy efficient over the history of the industry. • Oil sands production is largely fueled with energy from the bitumen resource itself, making external energy returns high. • Oil sands production is still significantly less efficient than conventional oil production

  12. Oil sands and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, R. [Shell Canada Ltd., Calgary, AB (Canada). Calgary Research Centre

    2004-07-01

    Oil sands are a significant resource for Alberta and Canada with continuing growth opportunity. There is a need to ensure sustainable development of the oil sands resources from a social, economic and environmental perspective. The industry has succeeded in terms of proven reserves, technology advancements, reduced operating costs, reliability and market accessibility. Some of the major challenges facing the industry include high capital cost, infrastructure, social services and keeping pace with growth. This presentation outlined the proactive measures that the oil sands industry has taken to manage environmental issues such as sulphur dioxide and nitrogen oxide emissions, greenhouse gases, water management and land reclamation. tabs., figs.

  13. Solvent extraction of Southern US tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Penney, W.R.

    1990-01-01

    The Department of Chemical Engineering at the University of Arkansas, in association with Diversified Petroleum Recovery, Inc. (DPR) of Little Rock, Arkansas, has been developing a solvent extraction process for the recovery of bitumen from tar sands for the past five years. The unique feature of the process is that the bitumen is recovered from the solvent by contacting with a co-solvent, which causes the bitumen to precipitate. The overall purpose of this project is to study both the technical and economic feasibility of applying this technology for recovery of bitumen from tar sands by (1) investigating the socioeconmic factors which affect (a) plant siting and (b) the market value of recovered bitumen; (2) operating a process demonstration unit at the rate of 1 lb/hr recovered bitumen while producing clean sand and recyclable solvents; and (3) determine the economic conditions which will make a bitumen recovery project economical. DPR has analyzed the historical trends of domestic production, consumption, discoveries and reserves of crude oil. They have started an investigation of the volatility in the price of crude oil and of gasoline prices and of the differential between gasoline and crude oil. DPR continues to analyze the geographical movement and demand for asphalt products. Utah does not appear economically attractive as a site for a bitumen from tar sands asphalt plant. Oklahoma sites are now being studied. This report also contains the quarterly progress report from a University of Nevada study to determine bitumen composition, oxygen uptake rates, and viscosities of Alabama and Utah bitumens. Both reports have been indexed separately for inclusion on the data base.

  14. Saltation of non-spherical sand particles.

    Directory of Open Access Journals (Sweden)

    Zhengshi Wang

    Full Text Available Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement.

  15. Reclaimability of the spent sand mixture – sand with bentonite – sand with furfuryl resin

    Directory of Open Access Journals (Sweden)

    J. Dańko

    2011-04-01

    Full Text Available Introduction of new binding materials and new technologies of their hardening in casting moulds and cores production requires theapplication of reclamation methods adequate to their properties as well as special devices realizing tasks. The spent sands circulationsystem containing the same kind of moulding and core sands is optimal from the point of view of the expected reclamation results.However, in the face of a significant variability of applied technologies and related to them various reclamation methods, the need - of theobtained reclamation products assessment on the grounds of systematic criteria and uniform bases – arises, with a tendency of indicatingwhich criteria are the most important for the given sand system. The reclaimability results of the mixture of the spent moulding sand withGeko S bentonite and the spent core sand with the Kaltharz 404U resin hardened by acidic hardener 100 T3, are presented in the paper.Investigations were performed with regard to the estimation of an influence of core sands additions (10 –25% on the reclaimed materialquality. Dusts and clay content in the reclaim, its chemical reaction (pH and ignition loss were estimated. The verification of the reclaiminstrumental assessment was performed on the basis of the technological properties estimation of moulding sand with bentonite, where the reclaimed material was used as a matrix.

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

    Science.gov (United States)

    Milhous, R.T.; ,

    2002-01-01

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

  17. Namibia : triaxial test on sand

    DEFF Research Database (Denmark)

    Steenfelt, Jørgen S.; Jacobsen, Kim P.

    In connection with a harbour project the friction angle of a fine sand is required. On Friday 13 March 1998 the Danish Geotechnical Institute (DGI) delivered app. 2.5 kg sand for testing at the Geotechnical Engineering Laboratory, Aalborg University. The present Data Report summarises the results...... of two CID, isotropically consolidated, drained triaxial tests carried out according to the instructions in DG1 letter dated 13 March 1998....

  18. Frac Sand Mines Are Preferentially Sited in Unzoned Rural Areas.

    Directory of Open Access Journals (Sweden)

    Christina Locke

    Full Text Available Shifting markets can cause unexpected, stochastic changes in rural landscapes that may take local communities by surprise. Preferential siting of new industrial facilities in poor areas or in areas with few regulatory restrictions can have implications for environmental sustainability, human health, and social justice. This study focuses on frac sand mining-the mining of high-quality silica sand used in hydraulic fracturing processes for gas and oil extraction. Frac sand mining gained prominence in the 2000s in the upper midwestern United States where nonmetallic mining is regulated primarily by local zoning. I asked whether frac sand mines were more commonly sited in rural townships without formal zoning regulations or planning processes than in those that undertook zoning and planning before the frac sand boom. I also asked if mine prevalence was correlated with socioeconomic differences across townships. After creating a probability surface to map areas most suitable for frac sand mine occurrence, I developed neutral landscape models from which to compare actual mine distributions in zoned and unzoned areas at three different spatial extents. Mines were significantly clustered in unzoned jurisdictions at the statewide level and in 7 of the 8 counties with at least three frac sand mines and some unzoned land. Subsequent regression analyses showed mine prevalence to be uncorrelated with land value, tax rate, or per capita income, but correlated with remoteness and zoning. The predicted mine count in unzoned townships was over two times higher than that in zoned townships. However, the county with the most mines by far was under a county zoning ordinance, perhaps indicating industry preferences for locations with clear, homogenous rules over patchwork regulation. Rural communities can use the case of frac sand mining as motivation to discuss and plan for sudden land-use predicaments, rather than wait to grapple with unfamiliar legal processes

  19. Frac Sand Mines Are Preferentially Sited in Unzoned Rural Areas.

    Science.gov (United States)

    Locke, Christina

    2015-01-01

    Shifting markets can cause unexpected, stochastic changes in rural landscapes that may take local communities by surprise. Preferential siting of new industrial facilities in poor areas or in areas with few regulatory restrictions can have implications for environmental sustainability, human health, and social justice. This study focuses on frac sand mining-the mining of high-quality silica sand used in hydraulic fracturing processes for gas and oil extraction. Frac sand mining gained prominence in the 2000s in the upper midwestern United States where nonmetallic mining is regulated primarily by local zoning. I asked whether frac sand mines were more commonly sited in rural townships without formal zoning regulations or planning processes than in those that undertook zoning and planning before the frac sand boom. I also asked if mine prevalence was correlated with socioeconomic differences across townships. After creating a probability surface to map areas most suitable for frac sand mine occurrence, I developed neutral landscape models from which to compare actual mine distributions in zoned and unzoned areas at three different spatial extents. Mines were significantly clustered in unzoned jurisdictions at the statewide level and in 7 of the 8 counties with at least three frac sand mines and some unzoned land. Subsequent regression analyses showed mine prevalence to be uncorrelated with land value, tax rate, or per capita income, but correlated with remoteness and zoning. The predicted mine count in unzoned townships was over two times higher than that in zoned townships. However, the county with the most mines by far was under a county zoning ordinance, perhaps indicating industry preferences for locations with clear, homogenous rules over patchwork regulation. Rural communities can use the case of frac sand mining as motivation to discuss and plan for sudden land-use predicaments, rather than wait to grapple with unfamiliar legal processes during a period of

  20. Technology unlocks tar sands energy

    Energy Technology Data Exchange (ETDEWEB)

    Law, C

    1967-09-25

    Tar sand processing technology has been developed primarily in the categories of extraction techniques and in-situ processing. In October, a $235 million venture into tar sand processing will be inspected by visitors from many points on the globe. A synthetic crude of premium quality will be flowing through a 16-in. pipeline from the Tar Island plant site of Great Canadian Oil Sands to Edmonton. This processing plant uses an extractive mining technique. The tar sand pay zone in this area averages approximately 150 ft in thickness with a 50-ft overburden. It has been estimated that the tar sands cannot be exploited when the formation thickness is less than 100 ft and overburden exceeds the same amount. This indicates that extraction techniques can only be used to recover approximately 15% of the tar sand deposits. An in-situ recovery technique developed by Shell of Canada is discussed in detail. In essence it is selective hydraulic fracturing, followed by the injection of emulsifying chemicals and steam.

  1. Appraisal of the tight sands potential of the Sand Wash and Great Divide Basins

    International Nuclear Information System (INIS)

    1993-08-01

    The volume of future tight gas reserve additions is difficult to estimate because of uncertainties in the characterization and extent of the resource and the performance and cost-effectiveness of stimulation and production technologies. Ongoing R ampersand D by industry and government aims to reduce the risks and costs of producing these tight resources, increase the certainty of knowledge of their geologic characteristics and extent, and increase the efficiency of production technologies. Some basins expected to contain large volumes of tight gas are being evaluated as to their potential contribution to domestic gas supplies. This report describes the results of one such appraisal. This analysis addresses the tight portions of the Eastern Greater Green River Basin (Sand Wash and Great Divide Subbasins in Northwestern Colorado and Southwestern Wyoming, respectively), with respect to estimated gas-in-place, technical recovery, and potential reserves. Geological data were compiled from public and proprietary sources. The study estimated gas-in-place in significant (greater than 10 feet net sand thickness) tight sand intervals for six distinct vertical and 21 areal units of analysis. These units of analysis represent tight gas potential outside current areas of development. For each unit of analysis, a ''typical'' well was modeled to represent the costs, recovery and economics of near-term drilling prospects in that unit. Technically recoverable gas was calculated using reservoir properties and assumptions about current formation evaluation and extraction technology performance. Basin-specific capital and operating costs were incorporated along with taxes, royalties and current regulations to estimate the minimum required wellhead gas price required to make the typical well in each of unit of analysis economic

  2. Effect of percentage of low plastic fines on the unsaturated shear strength of compacted gravel soil

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2015-06-01

    Full Text Available Low plastic fines in gravel soils affect its unsaturated shear strength due to the contribution of matric suction that arises in micro and macro pores found within and between aggregates. The shear strength of five different types of prepared gravel soils is measured and is compared with a theoretical model (Fredlund et al., 1978 to predict the unsaturated shear strength. The results are consistent to a great extent except the case of dry clayey gravel soil. It is also found that on inundation of gravel soils containing plastic fines greater than 12% a considerable reduction in both the strength and the stiffness modulus is noticed. This 12% percentage is close to the accepted 15% percentage of fines given by ASTM D4318 (American society for testing material. The angle of internal friction that arises due to matric suction decreases with the increase of degree of saturation of soil. The hysteresis of some tested gravel soils is measured and found that it increases by increasing the percentage of fines.

  3. Gravel admix, vegetation, and soil water interactions in protective barriers: Experimental design, construction, and initial conditions

    International Nuclear Information System (INIS)

    Waugh, W.J.

    1989-05-01

    The purpose of this study is to measure the interactive effects of gravel admix and greater precipitation on soil water storage and plant abundance. The study is one of many tasks in the Protective Barrier Development Program for the disposal of Hanford defense waste. A factorial field-plot experiment was set up at the site selected as the borrow area for barrier topsoil. Gravel admix, vegetation, and enhanced precipitation treatments were randomly assigned to the plots using a split-split plot design structure. Changes in soil water storage and plant cover were monitored using neutron probe and point intercept methods, respectively. The first-year results suggest that water extraction by plants will offset gravel-caused increases in soil water storage. Near-surface soil water contents were much lower in graveled plots with plants than in nongraveled plots without plants. Large inherent variability in deep soil water storage masked any effects gravel may have had on water content below the root zone. In the future, this source of variation will be removed by differencing monthly data series and testing for changes in soil water storage. Tests of the effects of greater precipitation on soil water storage were inconclusive. A telling test will be possible in the spring of 1988, following the first wet season during which normal precipitation is doubled. 26 refs., 9 figs., 9 tabs

  4. Characterization of napthenic acids in oil sands process-affected waters using fluorescence technology

    International Nuclear Information System (INIS)

    Brown, L.; Alostaz, M.; Ulrich, A.

    2009-01-01

    Process-affected water from oil sands production plants presents a major environmental challenge to oil sands operators due to its toxicity to different organisms as well as its corrosiveness in refinery units. This abstract investigated the use of fluorescence excitation-emission matrices to detect and characterize changes in naphthenic acid in oil sands process-affected waters. Samples from oil sands production plants and storage ponds were tested. The study showed that oil sands naphthenic acids show characteristic fluorescence signatures when excited by ultraviolet light in the range of 260 to 350 mm. The signal was a unique attribute of the naphthenic acid molecule. Changes in the fluorescence signature can be used to determine chemical changes such as degradation or aging. It was concluded that the technology can be used as a non-invasive continuous water quality monitoring tool to increase process control in oil sands processing plants

  5. Simultaneous sand control and liner cement system: keeping well productivity by optimizing drilling and completion operations in mature fields

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Andrea Nicolino de; Silva, Dayana Nunes e; Calderon, Agostinho [Petroleo Brasileiro S.A. (PETROBRAS), Rio de janeiro, RJ (Brazil)

    2012-07-01

    The need to reduce oil extraction costs by increasing the recovery factor in mature fields unconsolidated sandstone reservoirs motivated the development of drilling and completion techniques that integrate the various interfaces of engineering the well, resulting in a final well configuration that provides maximum oil production at a lower cost. Due to the continued growth of drilling and completion of new wells or deviation of old wells in the design of mesh density field with an advanced degree of exploitation, PETROBRAS took the challenge to seek options for projects well, in order to maintain productivity and reduce their construction time, with the optimization of drilling and sand control systems. To achieve these goals, PETROBRAS developed the SCARS - Simultaneous Sand Control and Liner Cementing System, a pioneer technique in the global oil industry, which consists of a one trip sequence of operations in which sand control screens and liner are installed followed by the open hole gravel pack operation performed with the alpha and beta waves deposition technique, using a non aqueous system as a carrier fluid. The sequence is completed by liner cementing in the same trip. The great success of this project was based on the definition of a specific application scenario and demands allowing optimization of the system. This project started with the development of a non aqueous system as a gravel pack carrier fluid in order to perform an open hole gravel pack with the alpha/beta wave deposition technique along with the development and optimization of SCARS procedures. This article details the planning and execution phases of this project and also presents a broad description of the technical aspects. (author)

  6. Development of practical decontamination process for the removal of uranium from gravel.

    Science.gov (United States)

    Kim, Ilgook; Kim, Gye-Nam; Kim, Seung-Soo; Choi, Jong-Won

    2018-01-01

    In this study, a practical decontamination process was developed to remove uranium from gravel using a soil washing method. The effects of critical parameters including particle size, H 2 SO 4 concentration, temperature, and reaction time on uranium removal were evaluated. The optimal condition for two-stage washing of gravel was found to be particle size of 1-2 mm, 1.0 M H 2 SO 4 , temperature of 60°C, and reaction time of 3 h, which satisfied the required uranium concentration for self-disposal. Furthermore, most of the extracted uranium was removed from the waste solution by precipitation, implying that the treated solution can be reused as washing solution. These results clearly demonstrated that our proposed process can be indeed a practical technique to decontaminate uranium-polluted gravel.

  7. Oil sands tailings management project

    Energy Technology Data Exchange (ETDEWEB)

    Godwalt, C. [Alberta WaterSMART, Calgary, AB (Canada); Kotecha, P. [Suncor Energy Inc, Calgary, AB (Canada); Aumann, C. [Alberta Innovates - Technology Futures, Alberta Governement, AB (Canada)

    2010-11-15

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  8. Oil sands tailings management project

    International Nuclear Information System (INIS)

    Godwalt, C.; Kotecha, P.; Aumann, C.

    2010-11-01

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  9. Construction of large-thickness sand cushions for NPP foundations

    International Nuclear Information System (INIS)

    Krantsfel'd, Ya.L.; Losievskaya, I.K.; Kovalenko, R.P.; Mutalipov, A.

    1982-01-01

    A study is made on some technological peculiarities of preparation of NPP foundations and control methods of foundation density. As an example the experience of cement-sand foundation construction for two 900 MW power-units at the Koeberg South Africa NPP is briefly described. The experience of artificial foundation construction at this NPP indicates both the possibility of obtaining the required quality of cement-sand cushions and commercial construction of large volume of such cushions by acceptable rates and the necessity of unification of work quality characteristics

  10. Western Gas Sands Project: stratigrapy of the Piceance Basin

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S. (comp.)

    1980-08-01

    The Western Gas Sands Project Core Program was initiated by US DOE to investigate various low permeability, gas bearing sandstones. Research to gain a better geological understanding of these sandstones and improve evaluation and stimulation techniques is being conducted. Tight gas sands are located in several mid-continent and western basins. This report deals with the Piceance Basin in northwestern Colorado. This discussion is an attempt to provide a general overview of the Piceance Basin stratigraphy and to be a useful reference of stratigraphic units and accompanying descriptions.

  11. Thermal remediation of tar-contaminated soil and oil-contaminated gravel

    International Nuclear Information System (INIS)

    Anthony, E.J.; Wang, J.

    2005-01-01

    High temperature treatments are commonly considered for the decontamination of soil as they have the advantages of reliability, high capacity, and effective destruction of hazardous materials with reduced long-term liability. This paper examined the remediation of soil contaminated by coal tar as well as gravel contaminated by oil. Pilot plant studies were conducted using 2 representative incineration technologies: rotary kiln and fluidized bed. The coal tar contaminated soil had accumulated over a few decades at a calcination plant in western Canada. The soil was sticky and could not be handled by conventional feeding and combustion systems. Crushed lignite was mixed with the soil as an auxiliary fuel and to reduce stickiness. A pilot plant furnace was used to evaluate the potential of decontamination in a rotary calciner. An analysis of both a modelling study and the test results showed that complete decontamination could be achieved in the targeted calciner. The results suggested that energy recovery was also possible, which could in turn make the remediation process more cost-effective. Decontamination of oil-contaminated gravel was conducted with a pilot plant fluidized bed combustor to study the feasibility of using incineration technology in the remediation of gravel and debris contaminated by oil spills. Results indicated that the gravel was decontaminated with acceptable emission performance. It was concluded that the study will be valuable to the application of commercial incineration processes for the remediation of polluted soils. It was observed that the weathering of the oiled gravel lowered the rate of decontamination. A small amount of salt water resulted in lowered decontamination rates, which may be an important factor for situations involving the remediation of shoreline gravel contaminated by oil. 24 refs., 6 tabs., 7 figs

  12. Holocene beach buildup and coastal aeolian sand incursions off the Nile littoral cell

    Science.gov (United States)

    Roskin, Joel; Sivan, Dorit; Shtienberg, Gilad; Porat, Naomi; Bookman, Revital

    2017-04-01

    Israel's coastal plain is abundant with sand originating from the Nile littoral cell. The inland windblown loose sand has formed 3-6 km wide lobe-like sand and dune fields currently comprised of foredunes, linear and northeasterly facing transverse and parabolic dunes that are currently stabilized by vegetation. This study reviews the architecture and history of the these dune fields aiming to: (a) Date the timings of beach accretion, and sand and dune incursions. (b) Discriminate between natural and human-induced forcing factors of sand mobilization and stabilization in time and space. (c) Present a model of the dunescape development. (d) Assess scenarios of sand transport in the future charcaterized by intense human impact and climate change. Luminescence ages, radiocarbon dates and relative ages from previously published geological and archaeological reports, historical texts, together with new optically stimulated luminescence (OSL) ages and stratigraphic and sedimentological data are analyzed. The deposition, mobilizations and preservation of the sand bodies, initially induced by the decline in sea level rise at 6-4 ka, were later controlled by historic land-use intensity and modern land-use/negligence practices. At 6 ka, beach sand buildup rapidly started. Where aeolianite ridges bordered the coast, pulses of sand with biogenic carbonate grains unconformably draped the ridges and rapidly consolidated into a distinct sandy calcarenite unit. Further east, sand sheets and low dunes partly pedogenized following their incursion, but did not cement. The water retention capacities of the sand sheets enabled the establishment of a sand-stabilizing vegetation cover that probably became an attractive environment for fuel and grazing. The growing Hellenistic-Roman-Byzantine ( 2.4-1.3 ka) populations probably led to increased consumption and massive destruction of sand stabilizing vegetation, enabling sand erodibility and mobilization during winter storms. The sand

  13. The Devil is in the Details: Using X-Ray Computed Tomography to Develop Accurate 3D Grain Characteristics and Bed Structure Metrics for Gravel Bed Rivers

    Science.gov (United States)

    Voepel, H.; Hodge, R. A.; Leyland, J.; Sear, D. A.; Ahmed, S. I.

    2014-12-01

    Uncertainty for bedload estimates in gravel bed rivers is largely driven by our inability to characterize the arrangement and orientation of the sediment grains within the bed. The characteristics of the surface structure are produced by the water working of grains, which leads to structural differences in bedforms through differential patterns of grain sorting, packing, imbrication, mortaring and degree of bed armoring. Until recently the technical and logistical difficulties of characterizing the arrangement of sediment in 3D have prohibited a full understanding of how grains interact with stream flow and the feedback mechanisms that exist. Micro-focus X-ray CT has been used for non-destructive 3D imaging of grains within a series of intact sections of river bed taken from key morphological units (see Figure 1). Volume, center of mass, points of contact, protrusion and spatial orientation of individual surface grains are derived from these 3D images, which in turn, facilitates estimates of 3D static force properties at the grain-scale such as pivoting angles, buoyancy and gravity forces, and grain exposure. By aggregating representative samples of grain-scale properties of localized interacting sediment into overall metrics, we can compare and contrast bed stability at a macro-scale with respect to stream bed morphology. Understanding differences in bed stability through representative metrics derived at the grain-scale will ultimately lead to improved bedload estimates with reduced uncertainty and increased understanding of interactions between grain-scale properties on channel morphology. Figure 1. CT-Scans of a water worked gravel-filled pot. a. 3D rendered scan showing the outer mesh, and b. the same pot with the mesh removed. c. vertical change in porosity of the gravels sampled in 5mm volumes. Values are typical of those measured in the field and lab. d. 2-D slices through the gravels at 20% depth from surface (porosity = 0.35), and e. 75% depth from

  14. Trace elements and radon in groundwater across the United States, 1992-2003

    Science.gov (United States)

    Ayotte, Joseph D.; Gronberg, Jo Ann M.; Apodaca, Lori E.

    2011-01-01

    greater concentrations of As, Ba, Pb, Li, Sr, V, and Zn, than samples from monitoring wells. In humid regions, however, concentrations of most trace elements were greater in monitoring wells than in drinking-water wells; the exceptions were Cu, Pb, Zn, and Rn. Cu, Pb, and Zn are common trace elements in pumps and pipes used in the construction of drinking-water wells, and contamination from these sources may have contributed to their concentrations. Al, Sb, Ba, B, Cr, Co, Fe, Mn, Mo, Ni, Se, Sr, and U concentrations were all greater in monitoring wells than in drinking-water wells in humid regions. Groundwater from wells in agricultural settings had greater concentrations of As, Mo, and U than groundwater from wells in urban settings, possibly owing to greater pH in the agricultural wells. Significantly greater concentrations of B, Cr, Se, Ag, Sr, and V also were found in agricultural wells in dry regions. Groundwater from dry-region urban wells had greater concentrations of Co, Fe, Pb, Li, Mn, and specific conductance than groundwater from agricultural wells. The geologic composition of aquifers and aquifer geochemistry are among the major factors affecting trace-element occurrence. Trace-element concentrations in groundwater were characterized in aquifers from eight major groups based on geologic material, including (1) unconsolidated sand and gravel; (2) glacial unconsolidated sand and gravel; (3) semiconsolidated sand; (4) sandstone; (5) sandstone and carbonate rock; (6) carbonate rock; (7) basaltic and other volcanic rock; and (8) crystalline rock. The majority of groundwater samples and the largest percentages of exceedences of HHBs were in the glacial and nonglacial unconsolidated sand and gravel aquifers; in these aquifers, As, Mn, and U are the most common trace elements exceeding HHBs. Overall, 19 percent of wells (962 of 5,097) exceeded an HHB for at least one trace element. The trace elements with HHBs included in this summary were Sb, As, Ba, Be, B, Cd, Cr,

  15. STRUCTURE, GROWTH AND MORPHOLOGY OF FISH POPULATIONS FROM GRAVEL-PIT VUKOVINA

    Directory of Open Access Journals (Sweden)

    Ivan Jakovlić

    2001-12-01

    Full Text Available After the structure of fish populations from gravel-pit Vukovina was determined, those populations were checked for 10 morphometric and 4 meristic parameters, as well as for length-mass relationship. For chub (Leuciscus cephalus and pumpkinseed (Lepomis gibbosus some meristic characters expressed the values beyond those mentioned in the standard key for the freshwater fish species determination. When compared to other locations, length-mass relationship and condition factor (CF were significantly lower for all checked populations. This indicates that gravel-pit Vukovina is extremely oligotrophic and has very poor fish production.

  16. Labour-based bitumen roads as cost-effective alternatives to conventional gravel wearing courses

    CSIR Research Space (South Africa)

    Paige-Green, P

    2004-09-01

    Full Text Available and streets. The potential for large-scale application of labour-based road works is therefore enormous. Delivery of a quality product is seen as key to the acceptance of labour-based road works. In Gundo Lashu it was realised early on that finding good... quality wearing course gravel in itself constituted a major problem in many areas of the province, thus bringing the costs for a fully rehabilitated and gravelled 5.5m wide road to about R230 000 in some instances. Aside from depleting an increasingly...

  17. Effects of Surface and Subsurface Bed Material Composition on Gravel Transport and Flow Competence Relations—Possibilities for Prediction

    Science.gov (United States)

    Bunte, K.; Abt, S. R.; Swingle, K. W.; Cenderelli, D. A.; Gaeuman, D. A.

    2014-12-01

    Bedload transport and flow competence relations are difficult to predict in coarse-bedded steep streams where widely differing sediment supply, bed stability, and complex flow hydraulics greatly affect amounts and sizes of transported gravel particles. This study explains how properties of bed material surface and subsurface size distributions are directly related to gravel transport and may be used for prediction of gravel transport and flow competence relations. Gravel transport, flow competence, and bed material size were measured in step-pool and plane-bed streams. Power functions were fitted to gravel transport QB=aQb and flow competence Dmax=cQd relations; Q is water discharge. Frequency distributions of surface FDsurf and subsurface FDsub bed material were likewise described by power functions FDsurf=hD j and FDsub=kDm fitted over six 0.5-phi size classes within 4 to 22.4 mm. Those gravel sizes are typically mobile even in moderate floods. Study results show that steeper subsurface bed material size distributions lead to steeper gravel transport and flow competence relations, whereas larger amounts of sediment contained in those 6 size bedmaterial classes (larger h and k) flatten the relations. Similarly, steeper surface size distributions decrease the coefficients of the gravel transport and flow competence relations, whereas larger amounts of sediment within the six bed material classes increase the intercepts of gravel transport and flow competence relations. Those relations are likely causative in streams where bedload stems almost entirely from the channel bed as opposed to direct (unworked) contributions from hillslopes and tributaries. The exponent of the subsurface bed material distribution m predicted the gravel transport exponent b with r2 near 0.7 and flow competence exponent d with r2 near 0.5. The intercept of bed surface distributions h increased the intercept a of gravel transport and c of the flow competence relations with r2 near 0.6.

  18. A Primer on Alberta’s Oil sands Royalties

    Directory of Open Access Journals (Sweden)

    Sarah Dobson

    2015-12-01

    Full Text Available Fulfilling its campaign promise, the new NDP government announced a review of Alberta’s royalty framework in June 2015. The province receives royalty revenue from three main sources – natural gas, crude oil, and oil sands. Since the 2009-10 fiscal year the largest contributor to Alberta’s royalty revenues has been the oil sands. If you want a sense of how important oil sands royalties have been for Alberta’s finances, consider this: In the 2014–15 fiscal year, the government collected just over $5 billion from oil sands royalties. These royalties covered over 10 per cent of the province’s operational expenses of $48.6 billion in the same fiscal year. Over the last six fiscal years the oil sands have contributed an average of 10 per cent of revenues to provincial coffers. This makes oil sands royalties the fourth largest contributor behind personal income taxes (23 per cent, federal transfers (13 per cent and corporate income taxes (11 per cent. But how many Albertans really understand how the royalty system works? What do we mean when we say “royalty”? How does the Alberta Government calculate royalties on oil sands producers? If the system is going to change, it’s important that Albertans understand how the current system works. That is what this paper is designed to do. For Albertans to properly judge the impact of new policy, they need a solid understanding of the current policy environment. We all know that oil prices have dropped and oil sands producers are losing profitability. As such, changes to the royalty system could have a deep and profound impact on the sector. Here are some of the issues this primer will study: • Pre-payout projects vs. post-payout projects, in other words, the classification of projects for royalty purposes based on whether the cumulative costs of a project exceed its cumulative revenues • Monthly payment of royalties vs. annual payment • Understanding the unit price of bitumen and how that

  19. Sands at Gusev Crater, Mars

    Science.gov (United States)

    Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

    2014-01-01

    Processes, 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).

  20. Western Gas Sands Project status report

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, C.H.

    1978-11-30

    Progress of government-sponsored projects directed toward increasing gas production from the low-permeability gas sands of the western United States is summarized. A Technology Implementation Plan (TIP) meeting was held at the CER office in Las Vegas, Nevada, October 16--19 to initiate the implementation phase of the Enhanced Gas Recovery (EGR) working group activities. A WGSP Logging Program meeting was conducted on October 24, 1978, at CER offices to define the problems associated with logs in tight gas sands. CER personnel and the project manager attended a two-day course on the fundamentals of core and reservoir analysis in Denver, Colorado, and met with USGS personnel to discuss USGS work on the WGSP. A meeting was held to discuss a contract for coring a Twin Arrow well on the Douglas Creek Arch, Colorado. CER Corporation personnel attended the Geological Society of America Annual Meeting held in Toronto, Canada, October 23--27 and a Gas Stimulation Workshop at Sandia Laboratories in Albuquerque, New Mexico, October 11 and 12 to discuss recent mineback experiments conducted at the Nevada Test Site. Fiscal year 1979 projects initiated by USGS and the Energy Technology Centers and National Laboratories are progressing as scheduled. Mobil Research and Development Corporation fractured zone 8 of the F-31-13G well in Rio Blanco County, Colorado. Colorado Interstate Gas Company poured the concrete pad for the compresser expected to be delivered in December and were laying pipeline between the wells at month end. The Mitchell Energy well, Muse Duke No. 1 was flowing on test at a rate of 2,100 Mcfd and preparations proceeded to fracture the well on November 15 with approximately 1,000,000 gal of fluid and 3,000,000 lb of sand. Terra Tek completed laboratory analyses of cores taken from the Mitchell Energy well.

  1. Evolution of Fine-Grained Channel Margin Deposits behind Large Woody Debris in an Experimental Gravel-Bed Flume

    Science.gov (United States)

    ONeill, B.; Marks, S.; Skalak, K.; Puleo, J. A.; Wilcock, P. R.; Pizzuto, J. E.

    2014-12-01

    Fine grained channel margin (FGCM) deposits of the South River, Virginia sequester a substantial volume of fine-grained sediment behind large woody debris (LWD). FGCM deposits were created in a laboratory setting meant to simulate the South River environment using a recirculating flume (15m long by 0.6m wide) with a fixed gravel bed and adjustable slope (set to 0.0067) to determine how fine sediment is transported and deposited behind LWD. Two model LWD structures were placed 3.7 m apart on opposite sides of the flume. A wire mesh screen with attached wooden dowels simulated LWD with an upstream facing rootwad. Six experiments with three different discharge rates, each with low and high sediment concentrations, were run. Suspended sediment was very fine grained (median grain size of 3 phi) and well sorted (0.45 phi) sand. Upstream of the wood, water depths averaged about 0.08m, velocities averaged about 0.3 m/s, and Froude numbers averaged around 0.3. Downstream of the first LWD structure, velocities were reduced tenfold. Small amounts of sediment passed through the rootwad and fell out of suspension in the area of reduced flow behind LWD, but most of the sediment was carried around the LWD by the main flow and then behind the LWD by a recirculating eddy current. Upstream migrating dunes formed behind LWD due to recirculating flow, similar to reattachment bars documented in bedrock canyon rivers partially obstructed by debouching debris fans. These upstream migrating dunes began at the reattachment point and merged with deposits formed from sediment transported through the rootwad. Downstream migrating dunes formed along the channel margin behind the LWD, downstream of the reattachment point. FGCM deposits were about 3 m long, with average widths of about 0.8 m. Greater sediment concentration created thicker FGCM deposits, and higher flows eroded the sides of the deposits, reducing their widths.

  2. Mechanisms of Cottonwood Establishment in Gravel-Bed Rivers, across Scales from the Bar to the Reach

    Science.gov (United States)

    Meier, C. I.

    2017-12-01

    Riparian cottonwoods are pioneer trees adapted to colonizing fluvial corridors, with strong effects on ecosystem structure and function. As their populations are being affected by flow alterations and invasive species, their recruitment mechanisms need to be understood, to support scientifically-based restoration efforts. I propose new concepts for cottonwood establishment in gravelly streams, from the local to the reach scale. These notions complement the currently-accepted ideas, which apply only to the landscape scale, and whose basic assumptions (existence of an alluvial water table, which is planar, almost horizontal, and linked to the river stage, with a parallel, spatially-uniform capillary fringe) seem to be based on a physical template that is only valid in the case of sand-bed streams. At the local, within-the-bar scale, two concepts drive establishment success. First, a finer matrix material helps retain more capillary water after the yearly snowmelt flood or a precipitation event. Second, the coarse surface layer of clean gravel and cobble acts as rock mulch, strongly decreasing evaporative losses. At the reach scale, we find that the commonly reported arcuate bands of cottonwoods do not depend on groundwater, but are caused by water dispersal (hydrochory). Wind-dispersed seeds fall into the river, are entrained into the drift, and start germinating as they travel under water. Some of the seeds and germinants find their way into the shallow, high relative roughness flow along the cobble shoreline. They are able to deposit in this environment, where they start growing, also under water. As waters recede, during the period of seed availability in the drift, the river seeds its banks and bars. Thus, the boundaries of observed bands and patches with successful seedling recruitment correspond to the location of flow profiles at different dates during the flood recession.

  3. Fly ash stabilisation of gravel roads; Flygaska som foerstaerkningslager i grusvaeg

    Energy Technology Data Exchange (ETDEWEB)

    Macsik, Josef

    2006-01-15

    Majority of the existing gravel roads have low bearing capacity during spring and autumn, due to thaw and/or rain. Low bearing capacity leads often to bad road conditions. This situation results in higher costs for the lumber industry and the public. Management of gravel roads all the year around would traditionally require excavation of frost susceptible soils and replacement with natural materials. Fly ash (from bio fuels) has good technical properties as bearing layer in road constructions. Fly ash stabilised gravel roads have better function and longer life span with less maintenance than traditional gravel roads. The aim of this project is to show how fly ash stabilisation of gravel roads can increase bearing capacity and what its environmental impact is. The overall aim is to make it easier for entrepreneurs and consulting companies to use fly ash during gravel road renovation and/or constructing new gravel roads. This report targets fly ash producers and road constructors as well as environmental agencies. Two different pilot tests were investigated in this study, Norberg with fly ash from Stora Enso Fors AB, and Boerje (Uppsala) with fly ash from Vattenfall Uppsala AB. Both road sections with related reference section were investigated during a two year period. Only fly ash was used in the bearing layer at Norberg and fly ash gravel was used at Boerje. Bearing capacity was investigated twice, for both locations, November 2003 one month after the road renovation and during thawing, April 2004. Water samples from lysimeters, ground water and surface water were only collected and analysed from Norberg. Experience from the fly ash stabilised road sections show that curing and traffic load can with time compensate for less compaction. The same is noticed at Boerje, although deflection measurements show that there are small differences. Stabilisation of gravel roads increases the roads bearing capacity. Two years after stabilisation 90 timber loads were

  4. Distribution and stability of potential salmonid spawning gravels in steep boulder-bed streams of the eastern Sierra Nevada

    International Nuclear Information System (INIS)

    Kondolf, G.M.; Cada, G.F.; Sale, M.J.; Felando, T.

    1991-01-01

    Interest in small hydroelectric development (< 5 MW) has recently focused attention on steep streams and the resident trout populations they contain. High-gradient boulder-bed streams have been the sites of relatively few studies of salmonid spawning habitat, although they have geomorphic and hydraulic characteristics - and therefore gravel distributions - that are quite different from the more commonly described lower-gradient channels. The authors documented gravel distribution in seven high-gradient stream reaches in the eastern Sierra Nevada. Gravels occurred only in locations characterized by relatively low shear stress; they formed small pockets in sites of low divergence and larger deposits upstream of natural hydraulic controls. In 1986 (a wet year), all tracer gravels placed in gravel pockets at nine sites on four streams were completely swept away, and substantial scour, fill, and other channel changes occurred at many sites. In 1987 (a dry year), tracer gravels and the channel cross sections were generally stable. Periodic mobility of gravel may explain why brown trout Salmo trutta are more abundant than rainbow trout Oncorhychus mykiss in the study reaches, where high flows occur every May and June during snowmelt. Brown trout are fall spawners, and their fry emerge long before the high snowmelt flows, whereas rainbow trout are spring spawners whose eggs are in the gravel, and thus vulnerable to scour, during snowmelt flows

  5. Resistivity profiling for mapping gravel layers that may control contaminant migration at the Amargosa Desert Research Site, Nevada

    Science.gov (United States)

    Lucius, Jeffrey E.; Abraham, Jared D.; Burton, Bethany L.

    2008-01-01

    Gaseous contaminants, including CFC 113, chloroform, and tritiated compounds, move preferentially in unsaturated subsurface gravel layers away from disposal trenches at a closed low-level radioactive waste-disposal facility in the Amargosa Desert about 17 kilometers south of Beatty, Nevada. Two distinct gravel layers are involved in contaminant transport: a thin, shallow layer between about 0.5 and 2.2 meters below the surface and a layer of variable thickness between about 15 and 30 meters below land surface. From 2003 to 2005, the U.S. Geological Survey used multielectrode DC and AC resistivity surveys to map these gravel layers. Previous core sampling indicates the fine-grained sediments generally have higher water content than the gravel layers or the sediments near the surface. The relatively higher electrical resistivity of the dry gravel layers, compared to that of the surrounding finer sediments, makes the gravel readily mappable using electrical resistivity profiling. The upper gravel layer is not easily distinguished from the very dry, fine-grained deposits at the surface. Two-dimensional resistivity models, however, clearly identify the resistive lower gravel layer, which is continuous near the facility except to the southeast. Multielectrode resistivity surveys provide a practical noninvasive method to image hydrogeologic features in the arid environment of the Amargosa Desert.

  6. Response of bed mobility to sediment supply in natural gravel bed channels: A detailed examination and evaluation of mobility parameters

    Science.gov (United States)

    T. E. Lisle; J. M. Nelson; B. L. Barkett; J. Pitlick; M. A. Madej

    1998-01-01

    Recent laboratory experiments have shown that bed mobility in gravel bed channels responds to changes in sediment supply, but detailed examinations of this adjustment in natural channels have been lacking, and practical methodologies to measure bed mobility have not been tested. We examined six gravel-bed, alternate-bar channels which have a wide range in annual...

  7. Modelling offshore sand wave evolution

    NARCIS (Netherlands)

    Nemeth, Attila; Hulscher, Suzanne J.M.H.; van Damme, Rudolf M.J.

    2007-01-01

    We present a two-dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of offshore sand waves. The model contains the 2DV shallow water equations, with a free water surface and a general bed load formula. The water movement is coupled to the sediment transport

  8. Rheology of oil sands slurries

    Energy Technology Data Exchange (ETDEWEB)

    Chow, R.; Zhou, J. [Alberta Research Council, Edmonton, AB (Canada). Mineral Oil Sands Unit; Wallace, D. [Dean Wallace Consulting Inc., Beaumont, AB (Canada)

    2006-07-01

    This study focused on integrating rheology and colloid science to improve recovery of bitumen in surface mined oil sands. Factors that influence recovery, such as conditions of particle interaction, solids concentration and shear rate, were reviewed. In an effort to understand the rheological behaviour of clay-in-water suspensions, an elaborate procedure was developed to separate an inter-bedded clay layer from a site at Albian Sands Energy Inc. The variables were water chemistry, solids concentration, and shear rate. The research study was conducted at the Alberta Research Council with the support of the CONRAD Extraction Group. A controlled stress rheometer was used to provide the quantitative evaluations of the clay slurry properties. The research results indicate that the viscoelastic properties of the slurry are highly influenced by the shear history of the slurry, solids content, calcium concentration, and sample aging. Shear thinning behaviour was observed in all slurry samples, but the slurry viscosity increased with test time for a given shear rate. In order to classify the slurries, a method was developed to distinguish the gel strength. The slurries were then classified into 3 distinct patterns, including no gel, weak gel and strong gel. The evolution of the experimental protocols were described along with the current stability maps that correlate the domains of the gel strength according to the solids concentration, calcium ion content, and shear rate. It was concluded that the rheological properties of oil sands slurries influence bitumen recovery in commercial surface-mined oil sands operations. tabs., figs.

  9. Geology on a Sand Budget

    Science.gov (United States)

    Kane, Jacqueline

    2004-01-01

    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…

  10. Response of Vegetation on Gravel Bars to Management Measures and Floods: Case Study From the Czech Republic

    Directory of Open Access Journals (Sweden)

    Eremiášová Renata

    2014-08-01

    Full Text Available This article investigates response of vegetation on gravel bars to management measures and floods. The management measures consisted of the partial removal of gravel and vegetation cover, and were applied to six gravel bars on the Ostravice River, Czech Republic. Unexpected floods occu-rred in 2010, with the amplitude of 5- to 50-year repetition. Research of vegetation on the gravel bars consisted of vegetation survey before the management works; the monitoring of vegetation development over the following year and the verification of the relationships of species diversity, successional stages and the biotope conditions with the help of multivariate analysis (detrended correspondence analysis. Vegetation on the gravel bars was at different successional stages, and had higher diversity and vegetation cover before the management measures and floods. The mul-tivariate analysis revealed a shift toward initial successional stages with high demand on moisture, temperature and light after both management measures and floods.

  11. Frost susceptibility of sub-base gravel used in Pearl-Chain Bridges: an experimental investigation

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Andersen, Iben Brøndum

    2016-01-01

    This study investigates frost susceptibility of sub-base gravel determined by the ASTM D5918-13 standard as a conservative estimate of the frost heave risk of fill in overfilled arch bridges, particularly in Pearl-Chain Bridges. Frost heave of granular materials has been of great research interes...

  12. Sediment transport primer: estimating bed-material transport in gravel-bed rivers

    Science.gov (United States)

    Peter Wilcock; John Pitlick; Yantao Cui

    2009-01-01

    This primer accompanies the release of BAGS, software developed to calculate sediment transport rate in gravel-bed rivers. BAGS and other programs facilitate calculation and can reduce some errors, but cannot ensure that calculations are accurate or relevant. This primer was written to help the software user define relevant and tractable problems, select appropriate...

  13. GRAIN-SIZE MEASUREMENTS OF FLUVIAL GRAVEL BARS USING OBJECT-BASED IMAGE ANALYSIS

    Directory of Open Access Journals (Sweden)

    Pedro Castro

    2018-01-01

    Full Text Available Traditional techniques for classifying the average grain size in gravel bars require manual measurements of each grain diameter. Aiming productivity, more efficient methods have been developed by applying remote sensing techniques and digital image processing. This research proposes an Object-Based Image Analysis methodology to classify gravel bars in fluvial channels. First, the study evaluates the performance of multiresolution segmentation algorithm (available at the software eCognition Developer in performing shape recognition. The linear regression model was applied to assess the correlation between the gravels’ reference delineation and the gravels recognized by the segmentation algorithm. Furthermore, the supervised classification was validated by comparing the results with field data using the t-statistic test and the kappa index. Afterwards, the grain size distribution in gravel bars along the upper Bananeiras River, Brazil was mapped. The multiresolution segmentation results did not prove to be consistent with all the samples. Nonetheless, the P01 sample showed an R2 =0.82 for the diameter estimation and R2=0.45 the recognition of the eliptical ft. The t-statistic showed no significant difference in the efficiencies of the grain size classifications by the field survey data and the Object-based supervised classification (t = 2.133 for a significance level of 0.05. However, the kappa index was 0.54. The analysis of the both segmentation and classification results did not prove to be replicable.

  14. The effect of coarse gravel on cohesive sediment entrapment in an annular flume

    Directory of Open Access Journals (Sweden)

    K. Glasbergen

    2015-03-01

    Full Text Available While cohesive sediment generally represents a small fraction (16 Pa, cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

  15. The relationship between emergence from spawning gravel and growth in farmed rainbow trout Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Åberg Andersson, Madelene; Laursen, Danielle Caroline; SILVA, P.I.M.

    2013-01-01

    The relationship between the timing of emergence from spawning gravel and growth after emergence was investigated in farmed Oncorhynchus mykiss. A relationship between the time of emergence and growth became evident after 6 months of rearing, where individuals with an intermediate emergence time...

  16. Sedimentology and composition of sands injected during the seismic crisis of May 2012 (Emilia, Italy): clues for source layer identification and liquefaction regime

    Science.gov (United States)

    Fontana, D.; Lugli, S.; Marchetti Dori, S.; Caputo, R.; Stefani, M.

    2015-07-01

    In May 2012 widespread sand blows formed along buried channels in the eastern sector of the Po Plain (Northern Italy) as a consequence of a series of seismic events with main shocks of Mw 6.1 and 5.9. At San Carlo (Ferrara) a trench dug a few week after the earthquakes exposed sand dikes cutting through an old Reno River channel-levee system that was diverted in the 18th century and was deposited starting from the 14th century (unit A). This sequence overlies a Holocene muddy floodplain deposits and contains scattered sandy channel deposits (unit B) and a Pleistocene channel sand unit (unit C). Sands with inverse and normal grading, concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fractures that were injected and filled by a slurry of sand during the compression pulses, and emptied during the extension phase. The pulse mechanism may have lasted for several minutes and formed well stratified sand volcanoes structures that formed at the top of the fractures. Sands from dikes and from the various units show well defined compositional fields from lithoarenitic to quartz-feldspar-rich compositions. Sands from the old Reno levee and channel fill (unit A) have abundant lithic fragments derived from the erosion of Apennine sedimentary carbonate and terrigenous successions. Composition of the sand filling the dikes show clear affinities with sand layers of the old Reno River channel (Unit A) and clearly differ from any sand from deeper Holocene and Pleistocene layers (Unit B and C), which are richer in quartz and feldspar and poorer in sedimentary lithic fragments. Sorting related to sediment flux variations did not apparently affect the sand composition across the sedimentary structures. Textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within Unit A at 6.8.to 7.5 m depth.

  17. Effects of Gravel Bars on Nutrient Spiraling in Bedrock-Alluvium Streams

    Science.gov (United States)

    Iobst, B. R.; Carroll, E. P.; Furbish, D. J.

    2007-05-01

    The importance of the connection between nutrient transport and local stream geomorphology is becoming increasingly important. Studies have shown that the interconnectivity of nutrient cycles in the downstream direction is in part controlled by the distribution and size of gravel bars in low order streams, as hyporheic flow occurs dominantly through alternate and mid-channel gravel bars. For this investigation multiple gravel bars in a 3rd order bedrock-alluvium stream were studied to determine general relationships between nutrient spiraling and hyporheic flow. The first goal was to understand (1) the extent to which water moves through hyporheic zones and (2) the basic chemistry of the hyporheic water. The second part of the study was to understand how nutrients, notably nitrogen, are affected in their cycling by the relatively long residence times encountered in gravel bars during hyporheic flow. Wells were installed along a 600 m reach of Panther Creek, KY in selected bars, as well as in a secondary location involving a grid installation pattern in one large bar. Results have shown that hyporheic flow through gravel bars is an important factor in influencing stream chemistry. Background water chemistry surveys have shown that certain parameters, specifically ammonium and nitrogen concentrations vary downstream, and that the dominant control over these changes is gravel bar location. Rhodamine WT was used in field tracer tests to track the travel times of water through bars as well as partitioning of water between the open channel and hyporheic flows. Further tests will be conducted utilizing a stable isotope study to determine how nitrogen is affected by hyporheic flow, and what implications this has for nutrient transport. We expect results to show that the spacing and size of gravel bars is a dominant control in key nutrient spiraling parameters, namely uptake lengths and overall nitrogen cycling rates. This has implications for how natural systems will

  18. Outer region scaling using the freestream velocity for nonuniform open channel flow over gravel

    Science.gov (United States)

    Stewart, Robert L.; Fox, James F.

    2017-06-01

    The theoretical basis for outer region scaling using the freestream velocity for nonuniform open channel flows over gravel is derived and tested for the first time. Owing to the gradual expansion of the flow within the nonuniform case presented, it is hypothesized that the flow can be defined as an equilibrium turbulent boundary layer using the asymptotic invariance principle. The hypothesis is supported using similarity analysis to derive a solution, followed by further testing with experimental datasets. For the latter, 38 newly collected experimental velocity profiles across three nonuniform flows over gravel in a hydraulic flume are tested as are 43 velocity profiles previously published in seven peer-reviewed journal papers that focused on fluid mechanics of nonuniform open channel over gravel. The findings support the nonuniform flows as equilibrium defined by the asymptotic invariance principle, which is reflective of the consistency of the turbulent structure's form and function within the expanding flow. However, roughness impacts the flow structure when comparing across the published experimental datasets. As a secondary objective, we show how previously published mixed scales can be used to assist with freestream velocity scaling of the velocity deficit and thus empirically account for the roughness effects that extend into the outer region of the flow. One broader finding of this study is providing the theoretical context to relax the use of the elusive friction velocity when scaling nonuniform flows in gravel bed rivers; and instead to apply the freestream velocity. A second broader finding highlighted by our results is that scaling of nonuniform flow in gravel bed rivers is still not fully resolved theoretically since mixed scaling relies to some degree on empiricism. As researchers resolve the form and function of macroturbulence in the outer region, we hope to see the closing of this research gap.

  19. Morphological evolution of the Maipo River in central Chile: Influence of instream gravel mining

    Science.gov (United States)

    Arróspide, Felipe; Mao, Luca; Escauriaza, Cristián

    2018-04-01

    Instream gravel mining is one of the most important causes of channel degradation in South America, specifically in rivers located near large metropolitan areas with rapidly growing cities, where no river management strategies exist. In the western region of the continent, many of these rivers belong to Andean systems, in which significant parts of the watersheds are located in mountain areas at high altitude, with considerable seasonal rainfall variability and steep channel slopes. In these rivers, gravel mining has produced significant incision of the channels with serious physical and ecological consequences, affecting habitats, modifying the supply and transport of sediments, and amplifying the risk to infrastructure in and around the channel during floods. In spite of the degraded conditions of many channels, no quantitative studies of the geomorphic impacts of gravel mining have been carried out in the region, mostly because of the insufficient and sparse data available. In this investigation we perform an analysis of the morphodynamic evolution in a section of the Maipo River in the metropolitan region of Santiago, Chile. This river is economically the most important in the country, as it provides drinking and irrigation water to urban and rural areas, is utilized by the energy generation industry, and runs along and below critical infrastructure. We have collected and analyzed data from 1954 to 2015, during which the city population increased by more than 5 million inhabitants whose presence accelerated land use changes. The analysis shows a rapid morphological evolution of the channel where in 31 years effects such as: river sections showing incision of up to 20 m, an increase of the area affected by gravel mining from 86.62 to 368.13 ha, and a net erosion volume of 39.4 million m3 can be observed. This work yields quantitative information on the consequences of gravel mining in the Maipo River, providing the necessary data to develop an integrated

  20. Tidal dynamics in the sand motor lagoon

    NARCIS (Netherlands)

    De Vries, S.; Radermacher, M.; De Schipper, M.A.; Stive, M.J.F.

    2015-01-01

    The Sand Motor is a mega-nourishment characterized by a very large sand volume of around 20 million m3 placed along the Dutch coast. The Sand Motor is a pilot project to evaluate the performance of an alternative nourishment strategy with respect to different functions of the coastal system. Within

  1. METHOD OF PROCESSING MONAZITE SAND

    Science.gov (United States)

    Welt, M.A.; Smutz, M.

    1958-08-26

    A process is described for recovering thorium, uranium, and rare earth values from monazite sand. The monazite sand is first digested with sulfuric acid and the resulting "monazite sulfate" solution is adjusted to a pH of between 0.4 and 3.0, and oxalate anions are added causing precipitation of the thorium and the rare earths as the oxalates. The oxalate precipitate is separated from the uranium containing supernatant solution, and is dried and calcined to the oxides. The thorium and rare earth oxides are then dissolved in nitric acid and the solution is contacted with tribntyl phosphate whereby an organic extract phase containing the cerium and thorium values is obtained, together with an aqueous raffinate containing the other rare earth values. The organic phase is then separated from the aqueous raffinate and the cerium and thorium are back extracted with an aqueous medium.

  2. Microbial community variation and functions to excess sludge reduction in a novel gravel contact oxidation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lin Shanshan; Jin, Y.; Fu, L. [School of Urban and Environmental Science, Northeast Normal University, Changchun (China); Quan, C. [Jilin University, College of medicine, Changchun (China); Yang, Y.S., E-mail: yangy6@cf.ac.uk [Cardiff University, School of Earth and Ocean Sciences, Cardiff CF10 3YE (United Kingdom)

    2009-06-15

    Excess biomass produced within the degradation processes of organic pollutants is creating environmental challenges. The gravel contact oxidation reactor (GCOR) filled with crushed stone globular aggregates as carriers, has been demonstrated capable of reducing the excess sludge effectively in some pilot and small-scale engineering studies. In order to evaluate the variation and structure of the microbial community and their functions to excess sludge reduction in GCOR, a conventional activated sludge reactor (ASR) was studied as a comparison. The 16S rDNA library of the universal bacteria was constructed, Shannon's diversity index (H) and Species evenness (E) were calculated with distance-based operational taxonomic unit and richness (DOTUR) for microbial diversity. Real-time quantity PCR and optical microscope were used for absolute bacterial DNA concentration and eukarya identification, respectively. Meanwhile, the suspended solid index in GCOR and ASR was detected for assessing the excess sludge production. The results indicated that the most abundant bacteria in GCOR were those related to the {beta}-Proteobacteria group, then {gamma}-Proteobacteria and to Cytophaga-Flexibacter-Bacteriode (CFB). In the ASR samples major bacteria were in the closest match with {gamma}-Proteobacteria, then {beta}-Proteobacteria and CFB. Shannon's index (H) was higher (3.41) for diversity of bacteria extracted from the carrier samples in GCOR than that (2.71) from the sludge sample in ASR. Species evenness (E) for the isolates from GCOR and ASR samples was 0.97 and 0.96, respectively. Comparison of the universal bacteria population in GCOR and ASR shows that the total bacterial DNA concentration on the GCOR carriers were 8.98 x 10{sup 5} {mu}g/{mu}l, twice that in ASR of 4.67 x 10{sup 5} {mu}g/{mu}l under normal operation of two reactors. But the MLSS in GCOR was only 4.5 mg/L, 25 times less than that in ASR of 115.4 mg/L. The most representative eukarya were protozoa

  3. Microbial community variation and functions to excess sludge reduction in a novel gravel contact oxidation reactor

    International Nuclear Information System (INIS)

    Lin Shanshan; Jin, Y.; Fu, L.; Quan, C.; Yang, Y.S.

    2009-01-01

    Excess biomass produced within the degradation processes of organic pollutants is creating environmental challenges. The gravel contact oxidation reactor (GCOR) filled with crushed stone globular aggregates as carriers, has been demonstrated capable of reducing the excess sludge effectively in some pilot and small-scale engineering studies. In order to evaluate the variation and structure of the microbial community and their functions to excess sludge reduction in GCOR, a conventional activated sludge reactor (ASR) was studied as a comparison. The 16S rDNA library of the universal bacteria was constructed, Shannon's diversity index (H) and Species evenness (E) were calculated with distance-based operational taxonomic unit and richness (DOTUR) for microbial diversity. Real-time quantity PCR and optical microscope were used for absolute bacterial DNA concentration and eukarya identification, respectively. Meanwhile, the suspended solid index in GCOR and ASR was detected for assessing the excess sludge production. The results indicated that the most abundant bacteria in GCOR were those related to the β-Proteobacteria group, then γ-Proteobacteria and to Cytophaga-Flexibacter-Bacteriode (CFB). In the ASR samples major bacteria were in the closest match with γ-Proteobacteria, then β-Proteobacteria and CFB. Shannon's index (H) was higher (3.41) for diversity of bacteria extracted from the carrier samples in GCOR than that (2.71) from the sludge sample in ASR. Species evenness (E) for the isolates from GCOR and ASR samples was 0.97 and 0.96, respectively. Comparison of the universal bacteria population in GCOR and ASR shows that the total bacterial DNA concentration on the GCOR carriers were 8.98 x 10 5 μg/μl, twice that in ASR of 4.67 x 10 5 μg/μl under normal operation of two reactors. But the MLSS in GCOR was only 4.5 mg/L, 25 times less than that in ASR of 115.4 mg/L. The most representative eukarya were protozoa both in GCOR (15 no. per 20 ml) and in ASR (15

  4. Gravel bars can be critical for biodiversity conservation: a case study on scaly-sided Merganser in South china.

    Directory of Open Access Journals (Sweden)

    Qing Zeng

    Full Text Available Gravel bars are characteristic components of river landscapes and are increasingly recognized as key sites for many waterbirds, though detailed studies on the ecological function of gravel bars for waterbirds are rare. In this study, we surveyed the endangered Scaly-sided Merganser Mergus squamatus along a 40 km river section of Yuan River, in Central China, for three consecutive winters. We derived the landscape metrics of river gravel bars from geo-rectified fine resolution (0.6 m aerial image data. We then built habitat suitability models (Generalized Linear Models-GLMs to study the effects of landscape metrics and human disturbance on Scaly-sided Merganser presence probability. We found that 1 the Scaly-sided Merganser tended to congregate at river segments with more gravel patches; 2 the Scaly-sided Merganser preferred areas with larger and more contiguous gravel patches; and 3 the number of houses along the river bank (a proxy for anthropogenic disturbance had significantly negative impacts on the occurrence of the Scaly-sided Merganser. Our results suggest that gravel bars are vital to the Scaly-sided Merganser as shelters from disturbance, as well as sites for feeding and roosting. Therefore, maintaining the exposure of gravel bars in regulated rivers during the low water period in winter might be the key for the conservation of the endangered species. These findings have important implications for understanding behavioral evolution and distribution of the species and for delineating between habitats of different quality for conservation and management.

  5. Sea sand for reactive barriers

    International Nuclear Information System (INIS)

    Garcia R, G.; Ordonez R, E.; Ordonez R, En.

    2002-01-01

    Some phosphates have the property to suck in radioactive metals in solution, what it is taken in advance to make reactive barriers which are placed in the nuclear waste repositories. In an effort for contributing to the study of this type of materials, it has been obtained the zirconium silicate (ZrSiO 4 ) and the alpha zirconium hydrogen phosphate (Zr(HPO 4 ) 2H 2 O) starting from sea sand in an easy and economic way. (Author)

  6. [Runoff and sediment yielding processes on red soil engineering accumulation containing gravels by a simulated rainfall experiment].

    Science.gov (United States)

    Shi, Qian-hua; Wang, Wen-long; Guo, Ming-ming; Bai, Yun; Deng, Li-qiang; Li, Jian-ming; Li, Yao-lin

    2015-09-01

    Engineering accumulation formed in production and construction projects is characterized by unique structure and complex material composition. Characteristics of soil erosion on the engineering accumulation significantly differ from those on farmland. An artificially simulated rainfall experiment was carried out to investigate the effects of rainfall intensity on the processes of runoff and sediment yielding on the engineering accumulation of different gravel contents (0%, 10%, 20% and 30%) in red soil regions. Results showed that the initial time of runoff generation decreased with increases in rainfall intensity and gravel content, the decreased amplitudes being about 48.5%-77.9% and 4.2%-34.2%, respectively. The initial time was found to be a power function of rainfall intensity. Both runoff velocity and runoff rate manifested a trend of first rising and then in a steady state with runoff duration. Rainfall intensity was found to be the main factor influencing runoff velocity and runoff rate, whereas the influence of gravel content was not significant. About 10% of gravel content was determined to be a critical value in the influence of gravel content on runoff volume. For the underlying surface of 10% gravel content, the runoff volume was least at rainfall intensity of 1.0 mm · min(-1) and maximum at rainfall intensity of greater than 1.0 mm · min(-1). The runoff volume in- creased 10%-60% with increase in rainfall intensity. Sediment concentration showed a sharp decline in first 6 min and then in a stable state in rest of time. Influence of rainfall intensity on sediment concentration decreased as gravel content increased. Gravels could reduce sediment yield significantly at rainfall intensity of greater than 1.0 mm · min(-1). Sediment yield was found to be a linear function of rainfall intensity and gravel content.

  7. Evaluating process origins of sand-dominated fluvial stratigraphy

    Science.gov (United States)

    Chamberlin, E.; Hajek, E. A.

    2015-12-01

    Sand-dominated fluvial stratigraphy is often interpreted as indicating times of relatively slow subsidence because of the assumption that fine sediment (silt and clay) is reworked or bypassed during periods of low accommodation. However, sand-dominated successions may instead represent proximal, coarse-grained reaches of paleo-river basins and/or fluvial systems with a sandy sediment supply. Differentiating between these cases is critical for accurately interpreting mass-extraction profiles, basin-subsidence rates, and paleo-river avulsion and migration behavior from ancient fluvial deposits. We explore the degree to which sand-rich accumulations reflect supply-driven progradation or accommodation-limited reworking, by re-evaluating the Castlegate Sandstone (Utah, USA) and the upper Williams Fork Formation (Colorado, USA) - two Upper Cretaceous sandy fluvial deposits previously interpreted as having formed during periods of relatively low accommodation. Both units comprise amalgamated channel and bar deposits with minor intra-channel and overbank mudstones. To constrain relative reworking, we quantify the preservation of bar deposits in each unit using detailed facies and channel-deposit mapping, and compare bar-deposit preservation to expected preservation statistics generated with object-based models spanning a range of boundary conditions. To estimate the grain-size distribution of paleo-sediment input, we leverage results of experimental work that shows both bed-material deposits and accumulations on the downstream side of bars ("interbar fines") sample suspended and wash loads of active flows. We measure grain-size distributions of bar deposits and interbar fines to reconstruct the relative sandiness of paleo-sediment supplies for both systems. By using these novel approaches to test whether sand-rich fluvial deposits reflect river systems with accommodation-limited reworking and/or particularly sand-rich sediment loads, we can gain insight into large

  8. Frost Resistance and Permeability of Cement Stabilized Gravel used as Filling Material for Pearl-Chain Bridges

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Hertz, Kristian Dahl

    2014-01-01

    several requirements on its moisture properties. In this paper the frost resistance, the liquid water permeability and the water vapour permeability of cement stabilized gravel are examined for two different cement contents. It is found that a small increase in cement content from 4% to 5% increases...... the 28-days compressive strength from 6.2 MPa to 12.3 MPa. The frost resistance of cement stabilized gravel with 5% cement content is better than for cement stabilized gravel with 4% cement content. The liquid water permeability coefficient and the water vapour permeability coefficient are significantly...

  9. Declines in a ground-dwelling arthropod community during an invasion by Sahara mustard (Brassica tournefortii) in aeolian sand habitats

    Science.gov (United States)

    Heather L. Hulton VanTassel; Anne M. Hansen; Cameron W. Barrows; Quresh Latif; Margaret W. Simon; Kurt E. Anderson

    2014-01-01

    Sahara Mustard (Brassica tournefortii; hereafter mustard), an exotic plant species, has invaded habitats throughout the arid southwestern United States. Mustard has reached high densities across aeolian sand habitats of southwestern deserts, including five distinct sand habitats in the eastern Coachella Valley, California. We examined trends in ground-dwelling...

  10. Isotope Investigations of Groundwater Movement in a Coarse Gravel Unsaturated Zone

    Energy Technology Data Exchange (ETDEWEB)

    Mali, N. [Geological Survey of Slovenia, Department of Hydrogeology, Ljubljana (Slovenia); Kozar-Logar, J. [Jozef Stefan Institute, Ljubljana (Slovenia); Leis, A. [Institute of Water Resources Management, Hydrogeology and Geophysics, Joanneum Research Forschungsgesellschaft mbH, Graz (Austria)

    2013-07-15

    The unsaturated zone above an aquifer serves as a water reservoir which discharges water and possible pollution to the saturated zone. This paper presents the application of oxygen-18 and tritium isotope methods in the study of groundwater transport processes in the unsaturated zone of Selniska Dobrava coarse gravel aquifer. The Selniska Dobrava gravel aquifer is an important water resource for Maribor and its surroundings, therefore the determination of transport processes in the unsaturated zone is important regarding its protection. Groundwater flow characteristics were estimated using isotopes and based on experimental work in a lysimeter. Tritium investigation results were compared with the results of long term oxygen-18 isotope investigation. In this paper the analytical approach, results and interpretation of {delta}{sup 18}O and tritium measurements in the unsaturated zone are presented. (author)

  11. From oil sands to transportation fuels, to electricity, to hydrogen

    International Nuclear Information System (INIS)

    Yildirim, E.

    1993-01-01

    The Alberta Chamber of Resources programs and initiatives on oil sands and heavy oil, and strategies for revitalizing oilsands development in Alberta are described. The regional upgrader and satellite production facilities concept, and technology requirements for mineable oil sands by the year 2010 are discussed. Strategic alliances in furtherence of oil sands research and development and the National Task Force on Oil Sands Strategies are described. Changes in requirements for transportation fuels due to stricter regulations and environmental initiatives will cause a trend to lighter fuels with more hydrogen content, less aromatics, nitrogen, sulfur and metals. A preferred refinery configuration will be able to process heavier crudes and synthetic crudes, have no heavy fuel oil product, low sulfur products, low aromatics with high octane, and low operating cost. A regional or central facility that combines the processing capabilities of a bitumen upgrader with the process units of a refinery is preferred. Advantages of this concept are: value addition to the feedstock is maximized; dependence on refineries is eliminated; restriction on synthetic crude oil volumes due to capacity limitations at refineries is eliminated; directly marketable finished products are produced; more stringent quality specifications are satisfied; and the synergies between upgrading and refining improve overall economics of processing. It is recommended that the concept of regional upgraders be adopted for Alberta, strategic alliances be encouraged, incentives for bitumen production be provided, and a bitumen pipeline network be developed. 12 refs

  12. Study of Slow Sand Filtration in Removing Total Coliforms and E.Coli

    Directory of Open Access Journals (Sweden)

    Ekha Yogafanny

    2015-08-01

    Full Text Available This study was aimed to evaluate the performance of SSF in removing bacteria (Total Coliforms and E. Coli in regard to grain size distribution and grain shape intermittently. Two methodological approaches used in this reasearch were literature review and laboratory work. Bacteria removal was analyzed considering two different filter media (Rhine sand-spherical shape and Lava sand-angular shape with three different grain size distributions. The best performance was attained by filter column F4 which consisted of Lava sand and had the configuration C2 (d10 = 0.07 mm; Cu = 4.2. This filter column achieved 4.7log-units removal of Total Coliforms and 5.0log-units removal of E. coli. The results show that a smaller grain size and an angular shape of sand grain lead to an increase in bacteria removal.

  13. Wall roughness effects on flow and scouring in curved channels with gravel bed

    OpenAIRE

    Hersberger, Daniel S.

    2002-01-01

    Wall roughness effects on flow and scouring in curved channels with gravel bed In the narrow valleys in Alpine regions, rivers frequently flow across constructed zones, passing through villages and cities. Due to limited space, the protection from high floods often needs to be ensured by protection walls. During floods, these protection walls may be endangered by scour phenomena, especially if they are located in bends. In the past, the potential danger of underscoured structures was reduced ...

  14. Barrier erosion control test plan: Gravel mulch, vegetation, and soil water interactions

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J.; Link, S.O. (Pacific Northwest Lab., Richland, WA (USA))

    1988-07-01

    Soil erosion could reduce the water storage capacity of barriers that have been proposed for the disposal of near-surface waste at the US Department of Energy's Hanford Site. Gravel mixed into the top soil surface may create a self-healing veneer that greatly retards soil loss. However, gravel admixtures may also enhance infiltration of rainwater, suppress plant growth and water extraction, and lead to the leaching of underlying waste. This report describes plans for two experiments that were designed to test hypotheses concerning the interactive effects of surface gravel admixtures, revegetation, and enhanced precipitation on soil water balance and plant abundance. The first experiment is a factorial field plot set up on the site selected as a soil borrow area for the eventual construction of barriers. The treatments, arranged in a a split-split-plot design structure, include two densities of gravel admix, a mixture of native and introduced grasses, and irrigation to simulate a wetter climate. Changes in soil water storage and plant cover are monitored with neutron moisture probes and point intercept sampling, respectively. The second experiment consists of an array of 80 lysimeters containing several different barrier prototypes. Surface treatments are similar to the field-plot experiment. Drainage is collected from a valve at the base of each lysimeter tube, and evapotranspiration is estimated by subtraction. The lysimeters are also designed to be coupled to a whole-plant gas exchange system that will be used to conduct controlled experiments on evapotranspiration for modeling purposes. 56 refs., 6 figs., 8 tabs.

  15. Plant succession patterns on residual open-pit gravel mines deposits Bogota

    OpenAIRE

    Ricardo A. Mora Goyes

    1999-01-01

    Based on both: the study of composition and structure of plant communities and the analysis of the physico-chemical characteristics of mining wastes, the initial patterns of primary succession were determined. These patterns were present in three deposits of waste material abandoned during 18, 36 and 120 months respectively. Sue materials were originated in open-pit gravel mines located to the south of Bogota (Colombia). This study pretends to contribute to the knowledge of the meehanlsms of ...

  16. Surface particle sizes on armoured gravel streambeds: Effects of supply and hydraulics

    Science.gov (United States)

    Peter J. Whiting; John G. King

    2003-01-01

    Most gravel-bed streams exhibit a surface armour in which the median grain size of the surface particles is coarser than that of the subsurface particles. This armour has been interpreted to result when the supply of sediment is less than the ability of the stream to move sediment. While there may be certain sizes in the bed for which the supply is less than the...

  17. Experiences made with tritium-containing water used as tracer in laboratory experiments with fluvioglacial gravels

    International Nuclear Information System (INIS)

    Klotz, D.; Rauert, W.

    1982-01-01

    Batch tests performed on 11 different Bavarian fluvioglacial gravels led to tritium distribution coefficients, which deviated not or only insignificantly from zero within the range of experimental accuracy applied to routine testings. The result of nine flow experiments in a gravelfilled column was a mean retardation factor of 1.01 +- 0.01. These experiments thus showed - as it had been expected - that 3 HHO is not significantly delayed with regard to the flow or movement of the water. (orig.) [de

  18. Physical Characteristics of Laboratory Tested Concrete as a Substituion of Gravel on Normal Concrete

    Science.gov (United States)

    Butar-butar, Ronald; Suhairiani; Wijaya, Kinanti; Sebayang, Nono

    2018-03-01

    Concrete technology is highly potential in the field of construction for structural and non-structural construction. The amount uses of this concrete material raise the problem of solid waste in the form of concrete remaining test results in the laboratory. This waste is usually just discarded and not economically valuable. In solving the problem, this experiment was made new materials by using recycle material in the form of recycled aggregate which aims to find out the strength characteristics of the used concrete as a gravel substitution material on the normal concrete and obtain the value of the substitution composition of gravel and used concrete that can achieve the strength of concrete according to the standard. Testing of concrete characteristic is one of the requirements before starting the concrete mixture. This test using SNI method (Indonesian National Standard) with variation of comparison (used concrete : gravel) were 15: 85%, 25: 75%, 35:65%, 50:50 %, 75: 25%. The results of physical tests obtained the mud content value of the mixture gravel and used concrete is 0.03 larger than the standard of SNI 03-4142-1996 that is equal to 1.03%. so the need watering or soaking before use. The water content test results show an increase in the water content value if the composition of the used concrete increases. While the specific gravity value for variation 15: 85% until 35: 65% fulfilled the requirements of SNI 03-1969-1990. the other variasion show the specifics gravity value included on the type of light materials.

  19. Evaluation of Hydraulic Parameters Obtained by Different Measurement Methods for Heterogeneous Gravel Soil

    Directory of Open Access Journals (Sweden)

    Chen Zeng

    2012-01-01

    Full Text Available Knowledge of soil hydraulic parameters for the van Genuchten function is important to characterize soil water movement for watershed management. Accurate and rapid prediction of soil water flow in heterogeneous gravel soil has become a hot topic in recent years. However, it is difficult to precisely estimate hydraulic parameters in a heterogeneous soil with rock fragments. In this study, the HYDRUS-2D numerical model was used to evaluate hydraulic parameters for heterogeneous gravel soil that was irregularly embedded with rock fragments in a grape production base. The centrifugal method (CM, tensiometer method (TM and inverse solution method (ISM were compared for various parameters in the van Genuchten function. The soil core method (SCM, disc infiltration method (DIM and inverse solution method (ISM were also investigated for measuring saturated hydraulic conductivity. Simulation with the DIM approach revealed a problem of overestimating soil water infiltration whereas simulation with the SCM approach revealed a problem of underestimating water movement as compared to actual field observation. The ISM approach produced the best simulation result even though this approach slightly overestimated soil moisture by ignoring the impact of rock fragments. This study provides useful information on the overall evaluation of soil hydraulic parameters attained with different measurement methods for simulating soil water movement and distribution in heterogeneous gravel soil.

  20. Bed Load Variability and Morphology of Gravel Bed Rivers Subject to Unsteady Flow: A Laboratory Investigation

    Science.gov (United States)

    Redolfi, M.; Bertoldi, W.; Tubino, M.; Welber, M.

    2018-02-01

    Measurement and estimation of bed load transport in gravel bed rivers are highly affected by its temporal fluctuations. Such variability is primarily driven by the flow regime but is also associated with a variety of inherent channel processes, such as flow turbulence, grain entrainment, and bed forms migration. These internal and external controls often act at comparable time scales, and are therefore difficult to disentangle, thus hindering the study of bed load variability under unsteady flow regime. In this paper, we report on laboratory experiments performed in a large, mobile bed flume where typical hydromorphological conditions of gravel bed rivers were reproduced. Data from a large number of replicated runs, including triangular and square-wave hydrographs, were used to build a statistically sound description of sediment transport processes. We found that the inherent variability of bed load flux strongly depends on the sampling interval, and it is significantly higher in complex, wandering or braided channels. This variability can be filtered out by computing the mean response over the experimental replicates, which allows us to highlight two distinctive phenomena: (i) an overshooting (undershooting) response of the mean bed load flux to a sudden increase (decrease) of discharge, and (ii) a clockwise hysteresis in the sediment rating curve. We then provide an interpretation of these findings through a conceptual mathematical model, showing how both phenomena are associated with a lagging morphological adaptation to unsteady flow. Overall, this work provides basic information for evaluating, monitoring, and managing gravel transport in morphologically active rivers.

  1. Synthesis of AL-MCM-41 using gravel drilling the source of silica from wells drilling

    International Nuclear Information System (INIS)

    Fontes, M.S.B.; Costa, C.C.; Melo, D.M.A.; Viana, L.M.; Viana, S.O.; Santos, L.M.

    2016-01-01

    The aim of this study was to synthesize Al-MCM-41 using gravel drilling as alternative source of silica, aiming at sustainable production and low cost. For hydrothermal synthesis of Al-MCM-41 was used gravel and sodium silicate as source of silica and sodium, respectively. The structural driver used was cetyltrimethylammonium bromide (CTMABr) and solvent distilled water. The hydrothermal synthesis was conducted at 100 ° C in a Teflon autoclave 45 ml jacketed stainless steel for a period of 120 hours with daily correcting pH (range 9-10) using 30% acetic acid. The material obtained was filtered, washed, dried at 100 ° C for 3 hours and then calcined at 550 ° C for 2 hours. Then it was characterized by XRD, FTIR and TG. For the results of characterization has been observed that the use of the gravel drilling as a source of silica was promising alternative for producing a mesoporous material with a high degree of hexagonal ordering. (author)

  2. Laboratory evidence for short and long-term damage to pink salmon incubating in oiled gravel

    International Nuclear Information System (INIS)

    Heintz, R.; Rice, S.; Wiedmer, M.

    1995-01-01

    Pink salmon, incubating in gravel contaminated with crude oil, demonstrated immediate and delayed responses in the laboratory at doses consistent with the concentrations observed in oiled streams in Prince William Sound. The authors incubated pink salmon embryos in a simulated intertidal environment with gravel contaminated by oil from the Exxon Valdez. During the incubation and emergence periods the authors quantified dose-response curves for characters affected directly by the oil. After emergence, fish were coded wire tagged and released, or cultured in netpens. Delayed responses have been observed among the cultured fish, and further observations will be made when coded wire tagged fish return in September 1995. The experiments have demonstrated that eggs need not contact oiled gravel to experience increased mortality, and doses as low as 17 ppb tPAH in water can have delayed effects on growth. A comparison of sediment tPAH concentrations from streams in Prince William Sound with these laboratory data suggests that many 1989 brood pink salmon were exposed to deleterious quantities of oil

  3. Cement Type Influence on Alkali-Silica Reaction in Concrete with Crushed Gravel Aggregate

    Science.gov (United States)

    Rutkauskas, A.; Nagrockienė, D.; Skripkiūnas, G.

    2017-10-01

    Alkali-silica reaction is one of the chemical reactions which have a significant influence for durability of concrete. During alkali and silica reaction, silicon located in aggregates of the concrete, reacts with high alkali content. This way in the micropores of concrete is forming hygroscopic gel, which at wet environment, expanding and slowly but strongly destroying concrete structures. The goal of this paper- to determine the influence of cement type on alkali-silica reaction of mortars with crushed gravel. In the study crushed gravel with fraction 4/16 mm was used and four types of cements tested: CEM I 42.5 R; CEM I 42.5 SR; CEM II/A-S 42.5; CEM II/A-V 52.5. This study showed that crushed gravel is low contaminated on reactive particles containing of amorphous silica dioxide. The expansion after 14 days exceed 0.054 %, by RILEM AAR-2 research methodology (testing specimen dimension 40×40×160 mm). Continuing the investigation to 56 days for all specimens occurred alkaline corrosion features: microcracking and the surface plaque of gel. The results showed that the best resistance to alkaline corrosion after 14 days was obtained with cement CEM I 42.5 SR containing ash additive, and after 56 days with cement CEM II/A-V 52.5 containing low alkali content. The highest expansion after 14 and 56 days was obtained with cement CEM I 42.5 R without active mineral additives.

  4. Wandering gravel-bed rivers and high-constructive stable channel sandy fluvial systems in the Ross River area, Yukon Territory, Canada

    Directory of Open Access Journals (Sweden)

    Darrel G.F. Long

    2011-07-01

    Gravel-dominated strata, inter-bedded with, and overlying coal-bearing units, are interpreted as deposits of wandering gravel-bed rivers, with sinuosity approaching 1.4. In most exposures they appear to be dominated by massive and thin planar-bedded granule to small pebble conglomerates, which would traditionally be interpreted as sheet-flood or longitudinal bar deposits of a high-gradient braided stream or alluvial fan. Architectural analysis of exposures in an open-pit shows that the predominance of flat bedding is an artefact of the geometry of the roadside exposures. In the pit the conglomerates are dominated by large scale cross stratification on a scale of 1–5.5 m. These appear to have developed as downstream and lateral accretion elements on side-bars and on in-channel bars in water depths of 2–12 m. Stacking of strata on domed 3rd order surfaces suggests development of longitudinal in-channel bar complexes similar to those observed in parts of the modern Rhône River system. Mudstone preserved in some of the channels reflects intervals of channel abandonment or avulsion. Minimum channel width is from 70 to 450 m.

  5. Studies in Phlebotomine Sand Flies.

    Science.gov (United States)

    1982-06-30

    Reporte de dos casos de [a ology of a sand fly, P/mlebolomu’,s diabolicuw Hall. in forma anergica difusa. Der matol. Rev. Mex. southwestern -Texas...Contribuiin al estudio de los Phmle- CDC, Veterinary Public Health Notes. USDHEW. bwmwnn de Costa Rica (Diptera, Psychodidae). Tesis. CDC. October. pp. 6- 7...janeiron R. j. 195 pp. the Unrited States (D1)pre ra: Psscfirdidae). j. Ortiz, 1. 1965a. Contribuci~in a! estudio tie los flebor- Partrsirtrl. 30:274-275

  6. Galveston Island, Texas, Sand Management Strategies

    Science.gov (United States)

    2016-07-01

    billion m3 of beach quality sand . However, Texas projects to date have not utilized these sources because of transportation costs. The lack of nearby...estimate that the San Luis Pass flood shoal contains approximately 11.8 million yd3 of beach quality sand . However, it is expected that if permits...a source of beach- quality sand . 2. Sand could be intercepted before it reaches the present dry beach. ERDC/CHL TR-16-13 55 3. The volume of

  7. Crushed rock sand – An economical and ecological alternative to natural sand to optimize concrete mix

    Directory of Open Access Journals (Sweden)

    Sanjay Mundra

    2016-09-01

    Full Text Available The study investigates the use of crushed rock sand as viable alternative to Natural River sand that is being conventionally used as fine aggregate in cement concrete. Various mix designs were developed for different grades of concrete based on IS, ACI and British codes using Natural River sand and crushed rock sand. In each case, the cube compressive strength test, and beam flexure tests were conducted. The results of the study show that, the strength properties of concrete using crushed rock sand are nearly similar to the conventional concrete. The study has shown that crushed stone sand can be used as economic and readily available alternative to river sand and can therefore help to arrest the detrimental effects on the environment caused due to excessive mining of river sand.

  8. Sand dune tracking from satellite laser altimetry

    Science.gov (United States)

    Dabboor, Mohammed

    Substantial problems arise from sand movement in arid and semi-arid countries. Sand poses a threat to infrastructure, agricultural and urban areas. These issues are caused by the encroachment of sand on roads and railway tracks, farmland, towns and villages, and airports, to name a few. Sand movement highly depends on geomorphology including vegetation cover, shape and height of the terrain, and grain size of the sand. However, wind direction and speed are the most important factors that affect efficient sand movement. The direction of the movement depends on the main direction of the wind, but it has been shown that a minimum wind speed is required, e.g. wind gusts, to initiate sand transport. This fact prevents a simple calculation of sand transport from conventional wind data as wind records rarely contain sub-minute intervals masking out any wind gusts. An alternative of predicting sand transport is the direct observation of sand advance by in situ measurements or via satellite. Until recently, satellite imagery was the only means to compare dune shape and position for predicting dune migration over several years. In 2003, the NASA laser altimetry mission ICESat became operational and monitors elevations over all surface types including sand dunes with an accuracy of about 10-20 cm. In this study, ICESat observations from repeat tracks (tracks overlapping eachother within 50 m) are used to derive sand dune advance and direction. The method employs a correlation of the elevation profiles over several dunes and was sucessfully validated with synthetic data. The accuracy of this method is 5 meters of dune advance. One of the most active areas exhibiting sand and dune movement is the area of the Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dunes. Different wind regimes (Shamal, Kaus) cause sand dune movement in the selected study area in the eastern part of the Arabian Peninsula between 20-25 degrees North and 45-55 degrees

  9. Submarine sand ridges and sand waves in the eastern part of the China Sea

    Science.gov (United States)

    Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

    2016-04-01

    Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

  10. Static Tension Tests on Axially Loaded Pile Segments in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    This paper provides laboratory test results of static axially loaded piles in sand. With a newly developed test setup, the pile-soil interface friction was investigated by using an open-ended steel pile segment with a diameter of 0.5 m. Use of a pile length of 1 m enabled the pile-soil interface...... friction to be analyzed at a given soil horizon while increasing the vertical effective stress in the sand. Test results obtained by this approach can be analyzed as single t-z curves and compared to predictions of unit shaft friction from current design methods for offshore foundations. The test results...... showed best agreement with the traditional design method given in the American Petroleum Institute (API) design code. When t-z curves obtained from the test results were compared to t-z curve formulations found in the literature, the Zhang formulation gave good predictions of the initial and post...

  11. Fuel options for oil sands

    International Nuclear Information System (INIS)

    Wise, T.

    2005-01-01

    This presentation examined fuel options in relation to oil sands production. Options include steam and hydrogen (H 2 ) for upgrading; natural gas by pipeline; bitumen; petroleum coke; and coal. Various cost drivers were also considered for each of the fuel options. It was noted that natural gas has high energy value but the capital cost is low, and that coke's energy value is very low but the capital cost is high. A chart forecasting energy prices was presented. The disposition of Western Canada's northern gas situation was presented. Issues concerning rail transportation for coal were considered. Environmental concerns were also examined. A chart of typical gas requirements for 75,000 B/D oil sands projects was presented. Issues concerning steam generation with gas and mining cogeneration with gas fuel and steam turbines were discussed, as well as cogeneration and H 2 with gas fuels and steam turbines. Various technology and fuel utility options were examined, along with details of equipment and processes. Boiler technologies were reviewed by type as well as fuel and steam quality and pressure. Charts of cogeneration with gas turbine and circulation fluid bed boilers were presented. Gasification processes were reviewed and a supply cost basis was examined. Cost drivers were ranked according to energy, operating considerations and capital investment. Results indicated that fuel costs were significant for gas and coal. Capital costs and capital recovery charge was most significant with coal and gasification technology. Without capital recovery, cash costs favour the use of bitumen and coke. Gasification would need lower capital and lower capital recovery to compete with direct burning. It was concluded that direct burning of bitumen can compete with natural gas. With price volatility anticipated, dual fuel capability for bitumen and gas has merit. Petroleum coke can be produced or retrieved from stockpiles. Utility supply costs of direct burning of coke is

  12. Study of Black Sand Particles from Sand Dunes in Badr, Saudi Arabia Using Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Haider Abbas Khwaja

    2015-08-01

    Full Text Available Particulate air pollution is a health concern. This study determines the microscopic make-up of different varieties of sand particles collected at a sand dune site in Badr, Saudi Arabia in 2012. Three categories of sand were studied: black sand, white sand, and volcanic sand. The study used multiple high resolution electron microscopies to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of surface “coatings or contaminants” deposited or transported by the black sand particles. White sand was comprised of natural coarse particles linked to wind-blown releases from crustal surfaces, weathering of igneous/metamorphic rock sources, and volcanic activities. Black sand particles exhibited different morphologies and microstructures (surface roughness compared with the white sand and volcanic sand. Morphological Scanning Electron Microscopy (SEM and Laser Scanning Microscopy (LSM analyses revealed that the black sand contained fine and ultrafine particles (50 to 500 nm ranges and was strongly magnetic, indicating the mineral magnetite or elemental iron. Aqueous extracts of black sands were acidic (pH = 5.0. Fe, C, O, Ti, Si, V, and S dominated the composition of black sand. Results suggest that carbon and other contaminant fine particles were produced by fossil-fuel combustion and industrial emissions in heavily industrialized areas of Haifa and Yanbu, and transported as cloud condensation nuclei to Douf Mountain. The suite of techniques used in this study has yielded an in-depth characterization of sand particles. Such information will be needed in future environmental, toxicological, epidemiological, and source apportionment studies.

  13. Understanding Colombian Amazonian white sand forests

    NARCIS (Netherlands)

    Peñuela-Mora, M.C.

    2014-01-01

    Although progress has been made in studies on white sand forests in the Amazon, there is still a considerable gap in our knowledge of the unique species composition of white sand forests and their structure and dynamics, especially in Western Amazon. This thesis aims to fill this gap by addressing

  14. Japan's involvement in oil sands development

    International Nuclear Information System (INIS)

    Sugiura, T.

    1994-01-01

    According to Japanese national policy, exploration and development by Japanese companies in overseas countries are promoted in order to ensure stable oil supplies. Japan Canada Oil Sands Limited (JACOS), part of the JAPEX group, was established during the 1978 world oil crisis to explore and develop Canadian oil sand resources in accordance with Japan's national policy. The JAPEX group, including JACOS, has invested $123 million in oil sands projects in Alberta. JAPEX's first involvement in oil sands was in the Primrose Project operated by Norcen in the Cold Lake area. Five years of cyclic steam stimulation pilot tests did not produce sufficiently good results to justify further operation. The second involvement was the PCEJ Project, a joint effort by four companies that are participating in a bitumen recovery test project in the Athabasca Deposit. JACOS holds 2,452 km 2 of oil sands leases in Alberta. Tests conducted since 1978 in the PCEJ Project include multiwell steam injection pilot tests, some of which showed promise. JACOS is also participating in steam assisted gravity drainage projects and in federal/provincial research programs. Obstacles identified in developing Alberta oil sands are the lack of a bitumen pipeline to Edmonton and the insufficient length of oil sands leases (currently 10 years), given the difficulties of oil sand development. 10 figs

  15. Seasonal fluctuations of phlebotomines sand fly populations ...

    African Journals Online (AJOL)

    An entomological survey of phlebotomine sand flies was conducted in the Moulay Yacoub province, central Morocco. An anthropic niche (Ouled Aid) and a wild niche (Zliligh) were selected. Sand flies were collected twice a month between April 2011 and March 2012, using sticky traps and CDC light traps. 3675 specimens ...

  16. On shelterbelt design for combating sand invasion.

    NARCIS (Netherlands)

    Mohammed, A.E.; Stigter, C.J.; Adam, H.S.

    1996-01-01

    After a review of the scarce literature on using trees against sand encroachment, a quantitative experiment with a wide shelterbelt to combat sand invasion is reported on. Experimental work was carried out at the northwestern border of the Gezira Scheme (Sudan), an area of severe land degradation

  17. Design of dry sand soil stratified sampler

    Science.gov (United States)

    Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

    2018-04-01

    This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

  18. Pattern formation - Instabilities in sand ripples

    DEFF Research Database (Denmark)

    Hansen, J. L.; v. Hecke, M.; Haaning, A.

    2001-01-01

    Sand ripples are seen below shallow wavy water and are formed whenever water oscillates over a bed of sand. Here we analyse the instabilities that can upset this perfect patterning when the ripples are subjected to large changes in driving amplitude or frequency, causing them to deform both...

  19. Gravel bar thermal variability and its potential consequences for CO2 evasion from Alpine coldwater streams

    Science.gov (United States)

    Boodoo, Kyle; Battin, Tom; Schelker, Jakob

    2017-04-01

    Gravel bars (GB) are ubiquitous in-stream structures with relatively large exposed surfaces, capable of absorbing heat and possibly acting as a heat source to the underlying hyporheic zone (HZ). The distinctive mixing of groundwater and surface water within their HZ largely determines its characteristic physical and biogeochemical properties, including temperature distribution. To study thermal variability within GBs and its possible consequences for CO2 evasion fluxes we analysed high frequency spatio-temporal data for a range of stream and atmospheric physical parameters including the vertical GB temperature, in an Alpine cold water stream (Oberer Seebach, Austria) over the course of a year. We found the vertical temperature profiles within the GB to vary seasonally and with discharge. We extended our study to 13 other gravel bars of varying physical characteristics within the surrounding Ybbs and Erlauf catchments, conducting diurnal spot samplings in summer 2016. Temperatures within the observed permanently wetted hyporheic zone (-56 to -100cm depth below GB surface) of the OSB, were warmer than both end members, surface water and groundwater >18% of the year, particularly during summer. There was a general increase in exceedance within the periodically wetted gravel bar sediment toward the gravel bar surface, further evidencing downward heat transfer to the wetted HZ. Average CO2 flux from the GB was significantly higher than that of streamwater during summer and winter, with significantly higher temperatures and CO2 outgassing rates occurring at the GB tail as compared to streamwater and the head and mid of the GB throughout the year. Higher cumulative (over 6 h) GB seasonal temperatures were associated with increased CO2 evasion fluxes within the OSB, particularly during summer. This enhanced CO2 flux may result from the input of warmer CO2-rich groundwater into the HZ in autumn, while downward heat transfer in summer may enhance GB metabolism and therefore

  20. Treatment of heavy metals by iron oxide coated and natural gravel media in Sustainable urban Drainage Systems.

    Science.gov (United States)

    Norris, M J; Pulford, I D; Haynes, H; Dorea, C C; Phoenix, V R

    2013-01-01

    Sustainable urban Drainage Systems (SuDS) filter drains are simple, low-cost systems utilized as a first defence to treat road runoff by employing biogeochemical processes to reduce pollutants. However, the mechanisms involved in pollution attenuation are poorly understood. This work aims to develop a better understanding of these mechanisms to facilitate improved SuDS design. Since heavy metals are a large fraction of pollution in road runoff, this study aimed to enhance heavy metal removal of filter drain gravel with an iron oxide mineral amendment to increase surface area for heavy metal scavenging. Experiments showed that amendment-coated and uncoated (control) gravel removed similar quantities of heavy metals. Moreover, when normalized to surface area, iron oxide coated gravels (IOCGs) showed poorer metal removal capacities than uncoated gravel. Inspection of the uncoated microgabbro gravel indicated that clay particulates on the surface (a natural product of weathering of this material) augmented heavy metal removal, generating metal sequestration capacities that were competitive compared with IOCGs. Furthermore, when the weathered surface was scrubbed and removed, metal removal capacities were reduced by 20%. When compared with other lithologies, adsorption of heavy metals by microgabbro was 10-70% higher, indicating that both the lithology of the gravel, and the presence of a weathered surface, considerably influence its ability to immobilize heavy metals. These results contradict previous assumptions which suggest that gravel lithology is not a significant factor in SuDS design. Based upon these results, weathered microgabbro is suggested to be an ideal lithology for use in SuDS.

  1. Flowability in crushed sand mortar

    Directory of Open Access Journals (Sweden)

    Cabrera, O. A.

    2010-12-01

    Full Text Available The present experimental study explored the relationship between mortar flowability and the voids content in crushed sand to determine the effect of grain shape and surface texture as well as dust content on the behaviour of fresh mortar. The findings revealed a close correlation between voids content and the volume of paste needed for mortar to begin to flow as a continuous material, mortar flowability and the water content needed to attain a given flowability. The comparison of the empirical findings to the results obtained with the Larrard (1, 2 model provided further information on the effect of sand grain morphology on fresh mortars.

    En el presente trabajo se plantea un estudio experimental de la fluidez de morteros basado en el contenido de vacíos de arenas machacadas, para comprender la influencia de la forma y textura superficial de los granos de arena y del contenido de polvo de las mismas sobre el estado fresco de morteros. Los resultados muestran la estrecha relación entre el contenido de vacíos entre granos y los volúmenes de pasta necesarios para iniciar el escurrimiento como un material continuo, la fluidez de los morteros, el contenido de agua para alcanzar una determinada fluidez, etc. El comportamiento evaluado se compara con resultados obtenidos aplicando el modelo de F. de Larrard (1, 2, permitiendo de este modo obtener mayor información de la influencia de la morfología de los granos de la arena sobre el estado fresco de los morteros.

  2. Sand transportation and reverse patterns over leeward face of sand dune

    Science.gov (United States)

    Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

    2017-04-01

    Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

  3. The morphodynamics and internal structure of intertidal fine-gravel dunes: Hills Flats, Severn Estuary, UK

    Science.gov (United States)

    Carling, P. A.; Radecki-Pawlik, A.; Williams, J. J.; Rumble, B.; Meshkova, L.; Bell, P.; Breakspear, R.

    2006-01-01

    In the macrotidal Severn estuary, UK, the dynamics of intertidal fine-gravel dunes were investigated. These dunes are migrating across a bedrock platform. Systematic observations were made of hydraulic climate, geometry, migration rates and internal sedimentary structures of the dunes. During spring tides, the ebb flow is dominant, dunes grow in height and have ebb orientated geometry with bedrock floors in the troughs. During neap tides, a weak flood flow may dominate. Dunes then are flood orientated or symmetrical. Neap dune heights decrease and the eroded sediment is stored in the dune troughs where the bedrock becomes blanketed by muddy gravel. During spring tides, instantaneous bed shear stresses reach 8 N m - 2 , sufficient to disrupt a 9 mm-gravel armour layer. However, a sustained bed shear stress of 4 N m - 2 is required to initiate dune migration at which time the critical depth-mean velocity is 1 m s - 1 . Ebb and flood inequalities in the bed shear stress explain the changes in dune asymmetry and internal structures. During flood tides, the crests of the dunes reverse such that very mobile sedimentary 'caps' overlie a more stable dune 'core'. Because ebb tides dominate, internal structures of the caps often are characterised by ebb orientated steep open-work foresets developed by strong tidal currents and some lower angle crossbeds deposited as weaker currents degrade foresets. The foresets forming the caps may be grouped into cosets (tidal bundles) and are separated from mud-infused cores of crossbeds that lie below, by reactivation and erosion surfaces blanketed by discontinuous mud drapes. The cores often exhibit distinctive muddy toe sets that define the spacing of tidal cosets.

  4. Numerical simulation of aeolian sand ripples

    International Nuclear Information System (INIS)

    Kang Liqiang; Guo Liejin

    2004-01-01

    With a new horizontal saltation displacement vector, a model is implemented to simulate the initiation and evolution of aeolian sand ripples. In the model, saltation distance considers the effects of surface height and slope. A linear stability analysis is also carried out for formation of sand ripples. The results show that, the model can be able to successfully reproduce sand ripples which can increase in scale by merging of small ripples. The linear stability analysis indicates that sand ripples appear when the relaxation rate parameter is below a threshold value and wind strength parameter is larger than a critical value. The results also verified that the formation of sand ripples is a self-organization process

  5. Plant succession patterns on residual open-pit gravel mines deposits Bogota

    Directory of Open Access Journals (Sweden)

    Ricardo A. Mora Goyes

    1999-07-01

    Full Text Available Based on both: the study of composition and structure of plant communities and the analysis of the physico-chemical characteristics of mining wastes, the initial patterns of primary succession were determined. These patterns were present in three deposits of waste material abandoned during 18, 36 and 120 months respectively. Sue materials were originated in open-pit gravel mines located to the south of Bogota (Colombia. This study pretends to contribute to the knowledge of the meehanlsms of natural restauration of tropical ecosystems subjected to man-borne degradation.

  6. Fluvial sediment inputs to upland gravel bed rivers draining forested catchments: potential ecological impacts

    Directory of Open Access Journals (Sweden)

    S. D. Marks

    1997-01-01

    Full Text Available As identified by the detailed long-term monitoring networks at Plynlimon, increased sediment supply to upland fluvial systems is often associated with forestry land-use and practice. Literature is reviewed, in the light of recent results from Plynlimon sediment studies, to enable identification of the potential ecological impacts of fluvial particulate inputs to upland gravel bed rivers draining forested catchments similar to the headwaters of the River Severn. Both sediment transport and deposition can have significant impacts upon aquatic vertebrates, invertebrates and plants.

  7. The diagnosis of old gravel aspiration in adults by MDCT: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Young; Lee, Ki Yeol; Seo, Bo Kyoung; Kim, Je Hyeong; Jung, Ki Hwan [Ansan Hospital, Korea University Medical Center, Ansan (Korea, Republic of)

    2008-03-15

    We report a case of old gravel aspiration in a 57-year-old man who had been accidentally buried in a field of construction for ten hours, three years prior. A chest radiograph showed peribronchial pneumonic infiltrates in the right lower lobe, with a proximal ovoid radiopaque endobronchial density at the trunchus basalis. These findings were more clearly visualized on the 64-channel multidetector CT (MDCT). Moreover, the patient recovered from his condition, following a bronchoscopic retrieval. However, the patient had persistent bronchiectasis of the right lower lobe on a subsequent follow-up chest radiograph, one month later.

  8. Numerical simulation of the free surface and water inflow of a slope, considering the nonlinear flow properties of gravel layers: a case study

    Science.gov (United States)

    Yang, Bin; Yang, Tianhong; Xu, Zenghe; Liu, Honglei; Shi, Wenhao; Yang, Xin

    2018-02-01

    Groundwater is an important factor of slope stability, and 90% of slope failures are related to the influence of groundwater. In the past, free surface calculations and the prediction of water inflow were based on Darcy's law. However, Darcy's law for steady fluid flow is a special case of non-Darcy flow, and many types of non-Darcy flows occur in practical engineering applications. In this paper, based on the experimental results of laboratory water seepage tests, the seepage state of each soil layer in the open-pit slope of the Yanshan Iron Mine, China, were determined, and the seepage parameters were obtained. The seepage behaviour in the silt layer, fine sand layer, silty clay layer and gravelly clay layer followed the traditional Darcy law, while the gravel layers showed clear nonlinear characteristics. The permeability increases exponentially and the non-Darcy coefficient decreases exponentially with an increase in porosity, and the relation among the permeability, the porosity and the non-Darcy coefficient is investigated. A coupled mathematical model is established for two flow fields, on the basis of Darcy flow in the low-permeability layers and Forchheimer flow in the high-permeability layers. In addition, the effect of the seepage in the slope on the transition from Darcy flow to Forchheimer flow was considered. Then, a numerical simulation was conducted by using finite-element software (FELAC 2.2). The results indicate that the free surface calculated by the Darcy-Forchheimer model is in good agreement with the in situ measurements; however, there is an evident deviation of the simulation results from the measured data when the Darcy model is used. Through a parameter sensitivity analysis of the gravel layers, it can be found that the height of the overflow point and the water inflow calculated by the Darcy-Forchheimer model are consistently less than those of the Darcy model, and the discrepancy between these two models increases as the permeability

  9. Soft Asphalt and Double Otta Seal—Self-Healing Sustainable Techniques for Low-Volume Gravel Road Rehabilitation

    Directory of Open Access Journals (Sweden)

    Audrius Vaitkus

    2018-01-01

    Full Text Available Increased traffic flow on low-volume gravel roads and deficiencies of national road infrastructure, are increasingly apparent in Lithuania. Gravel roads do not comply with requirements, resulting in low driving comfort, longer travelling time, faster vehicle amortization, and dustiness. The control of dustiness is one of the most important road maintenance activities on gravel roads. Another important issue is the assurance of required driving comfort and safety. Soft asphalt and Otta Seal technologies were proposed as a sustainable solution for the improvement of low-volume roads in Lithuania. Five gravel roads were constructed with soft asphalt, and 13 gravel roads were sealed with double Otta Seal, in 2012. The main aim of this research was to check soft asphalt and double Otta Seal’s ability to self-heal, on the basis of the results of the qualitative visual assessment of pavement defects and distress. The qualitative visual assessment was carried out twice a year following the opening of the rehabilitated road sections. The results confirmed soft asphalt and double Otta Seal’s ability to self-heal. The healing effect was more than 13% and 19% on roads with soft asphalt and double Otta Seal, respectively. In addition, on some roads, all cracks observed in spring self-healed during summer.

  10. Opposite hysteresis of sand and gravel transport upstream and downstream of a bifurcation during a flood in the River Rhine, the Netherlands

    NARCIS (Netherlands)

    Kleinhans, M.G.; Wilbers, A.W.E.; Brinke, W.B.M. ten

    2007-01-01

    At river bifurcations water and sediment is divided among the downstream branches. Prediction of the sediment transport rate and divisionthereof at bifurcations is of utmost importance for understanding the evolution of the bifurcates for short-term management purposes and forlong-term fluvial plain

  11. Life-history traits and habitat preferences of colonizing plant species in long-term spontaneous succession in abandoned gravel-sand pits

    Czech Academy of Sciences Publication Activity Database

    Řehounková, Klára; Prach, Karel

    2010-01-01

    Roč. 11, č. 1 (2010), s. 45-53 ISSN 1439-1791 R&D Projects: GA AV ČR IAA600050702 Institutional research plan: CEZ:AV0Z60050516 Keywords : life-histories * vegetation * success ion Subject RIV: EF - Botanics Impact factor: 2.199, year: 2010

  12. MONITORING AND CONTROLLING ON SURFACE SETTLEMENT IN SAND AND GRAVEL STRATA CAUSED BY SUBWAY STATION CONSTRUCTION APPLYING PIPE-ROOF PRE-CONSTRUCTION METHOD (PPM

    Directory of Open Access Journals (Sweden)

    Xian Yang

    2017-07-01

    Full Text Available Pipe-roof Pre-construction Method (PPM is regarded as a safer method to construct underground space, especially suitable for the construction sites with dense surface buildings, underground pipelines and complicated geological conditions. Xinleyizhi Station of Shenyang Metro constructed by PPM. In order to ensure safety in construction, the whole construction process was closely monitored. In this paper, monitoring results of surface settlement in PPM is analyzed. According to the monitoring results, the most serious settlement occurred in pipes jacking, which was the first and the most crucial step in PPM. The settlement reasons in each step are discussed, and controlling methods of surface settlement in each step are elaborated. Through close monitoring and timely control, the construction of Xinleyizhi Station completed smoothly. Because of the obvious advantages of PPM, the method will be used more widely in construction of shallow buried excavation under complicated surrounding and geological conditions.

  13. Geologic characterization of shelf areas using usSEABED for GIS mapping, modeling processes and assessing marine sand and gravel resources

    Science.gov (United States)

    Williams, S.J.; Bliss, J.D.; Arsenault, M.A.; Jenkins, C.J.; Goff, J.A.

    2007-01-01

    Geologic maps depicting offshore sedimentary features serve many scientific and applied purposes. Such maps have been lacking, but recent computer technology and software offer promise in the capture and display of diverse marine data. Continental margins contain landforms which provide a variety of important functions and contain important sedimentary records. Some shelf areas also contain deposits regarded as potential aggregate resources. Because proper management of coastal and offshore areas is increasingly important, knowledge of the framework geology and marine processes is critical. Especially valuable are comprehensive and integrated digital databases based on high-quality information from original sources. Products of interest are GIS maps containing thematic information, such as sediment character and texture. These products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The U.S. Geological Survey is leading a national program to gather a variety of extant marine geologic data into the usSEABED database system. This provides centralized, integrated marine geologic data collected over the past 50 years. To date, over 340,000 sediment data points from the U.S. reside in usSEABED, which combines an array of physical data and analytical and descriptive information about the sea floor and are available to the marine community through three USGS data reports for the Atlantic, Gulf of Mexico, and Pacific published in 2006, and the project web sites: (http://woodshole.er.usg s.gov/project-pages/aggregates/ and http://walrus.wr.usgs.gov/usseabed/)

  14. Application of Self Cleaning Rapid Sand Filter in Water Treatment

    Directory of Open Access Journals (Sweden)

    Ali Reza Rahmani

    2005-08-01

    Full Text Available Rapid sand filter is one of the most important units in the water treatment plants. It has some difficulties in operation such as backwashing. For the solving of this problem a rapid sand filter has designed and built with the self-cleaning backwashing system. This system consist of 3 main constituents; one galvanized siphon and two galvanized steel tanks. One of them is used for filtration and the other used for the storage of filtrated water in elevation for backwashing the system. Water enter from upside of the filter through the inlet pipe, and collected from the under drainage pipe. Then filter water conduct to the storage tank and exit from outlet pipe. In the beginning, the head loss was low, but because of bed clogging by suspended solids, it increases gradually to the designed head loss (1.2m. Then the system is outed of the service automatically and the backwash is began. The main data for the design of system selected from the hydraulic rules of siphons and rapid sand filter criteria. After essential calculations it was constructed and was started operation. For the hydraulic studies a known volume of storage tank was selected and the time needed for the fill (in filtration stage and empty (in backwash stage of water volume with volumetric method were measured. In hydraulic studies the filter surface rate (SOR was selected about 5-7.5m3/m2/hr (1.39-2.08 lit/sec and the flow of water in siphon, during the backwashing was measured 8.7 lit/sec. It can be seen that the siphon passes 4-6 times the inlet raw water thus a negative pressure will created in the siphon which causes the water above the sand bed to be discharged automatically and rinse water from elevated tank flow under the sand bed and back wash it. So according to this study self cleaning rapid sand filter is very useful for water filtration, especially in small population community. The construction of system is rapid, simple and economic.

  15. Barley root hair growth and morphology in soil, sand, and water solution media and relationship with nickel toxicity.

    Science.gov (United States)

    Lin, Yanqing; Allen, Herbert E; Di Toro, Dominic M

    2016-08-01

    Barley, Hordeum vulgare (Doyce), was grown in the 3 media of soil, hydroponic sand solution (sand), and hydroponic water solution (water) culture at the same environmental conditions for 4 d. Barley roots were scanned, and root morphology was analyzed. Plants grown in the 3 media had different root morphology and nickel (Ni) toxicity response. Root elongations and total root lengths followed the sequence soil > sand > water. Plants grown in water culture were more sensitive to Ni toxicity and had greater root hair length than those from soil and sand cultures, which increased root surface area. The unit root surface area as root surface area per centimeter of length of root followed the sequence water > sand > soil and was found to be related with root elongation. Including the unit root surface area, the difference in root elongation and 50% effective concentration were diminished, and percentage of root elongations can be improved with a root mean square error approximately 10% for plants grown in different media. Because the unit root surface area of plants in sand culture is closer to that in soil culture, the sand culture method, not water culture, is recommended for toxicity parameter estimation. Environ Toxicol Chem 2016;35:2125-2133. © 2016 SETAC. © 2016 SETAC.

  16. Critical State of Sand Matrix Soils

    Science.gov (United States)

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

    2014-01-01

    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, λ, and Γ. The range of the value of M, λ, and Γ 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

  17. The timing of scour and fill in a gravel-bedded river measured with buried accelerometers

    Science.gov (United States)

    Gendaszek, Andrew S.; Magirl, Christopher S.; Czuba, Christiana R.; Konrad, Christopher P.

    2013-01-01

    A device that measures the timing of streambed scour and the duration of sediment mobilization at specific depths of a streambed was developed using data-logging accelerometers placed within the gravel substrate of the Cedar River, Washington, USA. Each accelerometer recorded its orientation every 20 min and remained stable until the surrounding gravel matrix mobilized as sediment was transported downstream and scour reached the level of the accelerometer. The accelerometer scour monitors were deployed at 26 locations in salmon-spawning habitat during the 2010–2011 flood season to record when the streambed was scoured to the depth of typical egg-pocket deposition. Scour was recorded at one location during a moderate high-flow event (65 m3/s; 1.25–1.5-year recurrence interval) and at 17 locations during a larger high-flow event (159 m3/s; 7-year recurrence interval). Accelerometer scour monitors recorded periods of intermittent sediment mobilization and stability within a high-flow event providing insight into the duration of scour. Most scour was recorded during the rising limb and at the peak of a flood hydrograph, though some scour occurred during sustained high flows following the peak of the flood hydrograph.

  18. Soil erosion rates from mixed soil and gravel surfaces in a wind tunnel: A preliminary report

    International Nuclear Information System (INIS)

    Ligotke, M.W.

    1988-12-01

    Tests of wind erosion were performed in a controlled-environment wind tunnel to support the development of natural-material protective barriers for long-term isolation of radioactive waste. Barrier performance standards currently being developed for internal and external barrier performance are expected to mandate a surface layer that is resistant to wind erosion. The purpose of this study was to initiate a series of tests to determine suitable soil and gravel mixtures for such a barrier and to test worst-case surface layer conditions under the influence of high wind speeds. Six mixed soil and gravel surfaces were prepared, weathered to represent natural wind-blown desert areas, and subjected to controlled wind erosion forces in a wind tunnel. The applied erosive forces, including surface shear forces, were characterized to provide a means of relating wind tunnel results with actual field conditions. Soil particle losses from the surfaces caused by suspension, saltation, and surface creep were monitored by aerosol sample probes and mass balance measurements. 23 refs., 22 figs., 3 tabs

  19. The possibility of using materials based on secondary gravel in civil construction

    Directory of Open Access Journals (Sweden)

    Galitskova Yulia

    2017-01-01

    Full Text Available By now, the wear and tear of housing stock is more than 50%. Each year the number of old and dilapidated housing is growing, but it is gradually replaced by modern buildings. However, wastes accumulated from dismantling of buildings and constructions, are underutilized and, usually are just stored at landfills, or used for temporary roads construction. The purpose of this research is to define construction wastes characteristics and to explore possibilities for recycling of wastes from construction materials production. The paper also analyzes housing stock condition and basic requirements to building materials used in construction; and demonstrates results building materials based on secondary gravel investigation. While working with materials based on waste requirements the authors conducted laboratory research. Thus, the paper presents the analysis of laboratory tests results that made it possible to draw conclusions about the possible use of building materials based on secondary gravel and about their conformity to specified requirements. The researchers also developed proposals and recommendations to improve the competitiveness of such materials.

  20. Horizontal drilling in Miocene thin sand of Lake Maracaibo

    Energy Technology Data Exchange (ETDEWEB)

    Partidas, C. [PDVSA Exploration and Production (Venezuela)

    1998-12-31

    Horizontal drilling in the mature Lake Maracaibo field in Venezuela as a means of stimulating production are discussed. The Miocene sand where the horizontal well technology was applied, presented a number of intervals of unconsolidated sand of varied continuity, pay intervals at ten to twenty feet thickness, and reservoir pressures mostly at hydrostatic or below hydrostatic values. This paper evaluates a horizontal drilling program in the Lagunallis Lago Production Unit of Maracaibo, involving 91 wells to date (since 1995). When assessed in economic terms, results indicate that horizontal wells are a better economic alternative than vertical wells. The same results also showed that drainage from thin sand reservoirs resulted in better production with horizontal well technology than production from vertical wells. Payout was less than two years for 50 per cent of the horizontal wells while 40 per cent had payouts of between two and four years. Profit to investment ratio was greater than two in the case of about 70 per cent of the horizontal wells drilled in 1996. 2 tabs., 10 figs.

  1. Slow sand filters effectively reduce Phytophthora after a pathogen switch from Fusarium and a simulated pump failure.

    Science.gov (United States)

    Lee, Eric; Oki, Lorence R

    2013-09-15

    Slow sand filtration has been shown to effectively reduce Phytophthora zoospores in irrigation water. This experiment tested the reduction of Phytophthora colony forming units (CFUs) by slow sand filtration systems after switching the pathogen contaminating plant leachate from Fusarium to Phytophthora and the resilience of the system to a short period without water, as might be caused by a pump failure. The slow sand filtration system greatly reduced Phytophthora CFUs and transmission after switching the pathogens. In addition, Phytophthora reduction by the slow sand filter was equally effective before and after the simulated pump failure. Reduction of Fusarium was not seen by the SSFs, before or after the simulated pump failure. The results suggest that slow sand filters are effective at reducing larger organisms, such as Phytophthora zoospores, even after a pump failure or a change in pathogens. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Watching Faults Grow in Sand

    Science.gov (United States)

    Cooke, M. L.

    2015-12-01

    Accretionary sandbox experiments provide a rich environment for investigating the processes of fault development. These experiments engage students because 1) they enable direct observation of fault growth, which is impossible in the crust (type 1 physical model), 2) they are not only representational but can also be manipulated (type 2 physical model), 3) they can be used to test hypotheses (type 3 physical model) and 4) they resemble experiments performed by structural geology researchers around the world. The structural geology courses at UMass Amherst utilize a series of accretionary sandboxes experiments where students first watch a video of an experiment and then perform a group experiment. The experiments motivate discussions of what conditions they would change and what outcomes they would expect from these changes; hypothesis development. These discussions inevitably lead to calculations of the scaling relationships between model and crustal fault growth and provide insight into the crustal processes represented within the dry sand. Sketching of the experiments has been shown to be a very effective assessment method as the students reveal which features they are analyzing. Another approach used at UMass is to set up a forensic experiment. The experiment is set up with spatially varying basal friction before the meeting and students must figure out what the basal conditions are through the experiment. This experiment leads to discussions of equilibrium and force balance within the accretionary wedge. Displacement fields can be captured throughout the experiment using inexpensive digital image correlation techniques to foster quantitative analysis of the experiments.

  3. Sudan challenges the sand dragon.

    Science.gov (United States)

    Tinker, J

    1978-01-01

    Formerly productive areas have become wasteland as the desert advances in the Sudan. To understand how desertification is undermining the very survival of the Sahel, one ecosystem is reviewed in detail here: the gum arabic zone of Kordofan. After cotton, gum arabic is Sudan's largest export, worth from $14-26 million in recent years. In this zone the ecologically balanced cycle of gum gardens, fire, grain crops, and fallow is now breaking down; the 1968-1973 drought having in many areas delivered the final blow. Because of a growing population, the cultivation period is extended, and the soil becomes impoverished. Overgrazing in the fallow period, and the lopping of gum trees for firewood is producing a low return on the gum trees. Without this gum to harvest for cash, farmers must repeatedly replant their subsistence crops until the land becomes useless sand. The Sudanese have recognized the problem earlier than most, and a number of imaginative and practicable pilot projects are already in use: 1) waterpoint management; 2) construction of firebreaks; 3) land threatened by shifting dunes has been enclosed by stockproof fence and afforested with local trees; and 4) shelter belts have been planted around town perimeters where old gum tree stumps have started to sprout and the grass is reseeding itself. Out of these pilot projects, and with the advice of the U.N. Environment Program, the U.N. Development Program, and FAO, the Sudanese have developed a modest $26 million desert encroachment control and rehabilitation program (DECARP).

  4. Sand to Root Transfer of PAHs and PCBs by Carrots Grown on Sand with Pure Substances and Biosolids Amended Sand

    OpenAIRE

    Sablayrolles, Caroline; Montréjaud-Vignoles, Mireille; Silvestre, Jérôme; Patria, Lucie

    2006-01-01

    A study on behaviour of trace organic compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Polychlorinated Biphenyls, PCB) in a sand-plant system has been carried out, with the reclamation of wastewater treatment plant biosolids for agriculture in mind. Carrot plants (Daucus carota) were grown on soilless culture (sand), to provide optimal transfer conditions, in plant containers inside a temperature regulated greenhouse. There were two types of experiment. The trace organic compounds have i...

  5. Extraction of toxic and valuable metals from foundry sands

    International Nuclear Information System (INIS)

    Vite T, J.

    1996-01-01

    There were extracted valuable metals from foundry sands such as: gold, platinum, silver, cobalt, germanium, nickel and zinc among others, as well as highly toxic metals such as chromium, lead, vanadium and arsenic. The extraction efficiency was up to 100% in some cases. For this reason there were obtained two patents at the United States, patent number 5,356,601, in October 1994, given for the developed process and patent number 5,376,000, in December 1994, obtained for the equipment employed. Therefore, the preliminary parameters for the installation of a pilot plant have also been developed. (Author)

  6. McGET: A rapid image-based method to determine the morphological characteristics of gravels on the Gobi desert surface

    Science.gov (United States)

    Mu, Yue; Wang, Feng; Zheng, Bangyou; Guo, Wei; Feng, Yiming

    2018-03-01

    The relationship between morphological characteristics (e.g. gravel size, coverage, angularity and orientation) and local geomorphic features (e.g. slope gradient and aspect) of desert has been used to explore the evolution process of Gobi desert. Conventional quantification methods are time-consuming, inefficient and even prove impossible to determine the characteristics of large numbers of gravels. We propose a rapid image-based method to obtain the morphological characteristics of gravels on the Gobi desert surface, which is called the "morphological characteristics gained effectively technique" (McGET). The image of the Gobi desert surface was classified into gravel clusters and background by a machine-learning "classification and regression tree" (CART) algorithm. Then gravel clusters were segmented into individual gravel clasts by separating objects in images using a "watershed segmentation" algorithm. Thirdly, gravel coverage, diameter, aspect ratio and orientation were calculated based on the basic principles of 2D computer graphics. We validated this method with two independent datasets in which the gravel morphological characteristics were obtained from 2728 gravels measured in the field and 7422 gravels measured by manual digitization. Finally, we applied McGET to derive the spatial variation of gravel morphology on the Gobi desert along an alluvial-proluvial fan located in Hami, Xinjiang, China. The validated results show that the mean gravel diameter measured in the field agreed well with that calculated by McGET for large gravels (R2 = 0.89, P < 0.001). Compared to manual digitization, the McGET accuracies for gravel coverage, gravel diameter and aspect ratio were 97%, 83% and 96%, respectively. The orientation distributions calculated were consistent across two different methods. More importantly, McGET significantly shortens the time cost in obtaining gravel morphological characteristics in the field and laboratory. The spatial variation results

  7. Geomorphic responses to dam removal in the United States – a two-decade perspective

    Science.gov (United States)

    Major, Jon J.; East, Amy; O'Connor, Jim E.; Grant, Gordon E.; Wilcox, Andrew C.; Magirl, Christopher S.; Collins, Matthias J.; Tullos, Desiree D.; Tsutsumi, Daizo; Laronne, Jonathan B.

    2017-01-01

    Recent decades have seen a marked increase in the number of dams removed in the United States. Investigations following a number of removals are beginning to inform how, and how fast, rivers and their ecosystems respond to released sediment. Though only a few tens of studies detail physical responses to removals, common findings have begun to emerge. They include: (1) Rivers are resilient and respond quickly to dam removals, especially when removals are sudden rather than prolonged. Rivers can swiftly evacuate large fractions of reservoir sediment (≥50% within one year), especially when sediment is coarse grained (sand and gravel). The channel downstream typically takes months to years—not decades—to achieve a degree of stability within its range of natural variability. (2) Modest streamflows (<2-year return interval flows) can erode and transport large amounts of reservoir sediment. Greater streamflows commonly are needed to access remnant reservoir sediment and transport it downstream. (3) Dam height, sediment volume, and sediment caliber strongly influence downstream response to dam removal. Removals of large dams (≥10 m tall) have had longer-lasting and more widespread downstream effects than more common removals of small dams. (4) Downstream valley morphology and position of a dam within a watershed influence the distribution of released sediment. Valley confinement, downstream channel gradient, locations and depths of channel pools, locations and geometries of extant channel bars, and locations of other reservoirs all influence the downstream fate of released sediment.

  8. experimental studies of sand production from unconsolidated

    African Journals Online (AJOL)

    ES Obe

    aDepartment of Chemical Engineering, University of Lagos, Lagos, Nigeria. bDepartment of Petroleum ... as risk of well failure, erosion of pipelines and surface facilities, sand separa- ... ment, theoretical and numerical analysis have lead to the ...

  9. A study of global sand seas

    Science.gov (United States)

    McKee, Edwin D.

    1979-01-01

    The birth of the idea that led to this publication on "Global Sand Seas" dates back to the late 1920's. At that time I was engaged in a study of the Coconino Sandstone of Arizona's Grand Canyon. Considerable controversy existed then as to whether this sandstone was a subaqueous deposit or was composed of wind-formed dunes. It became apparent that definitive literature was sparse or lacking on types of dunes, global distribution of these types, the mechanics of their development, the precise nature of their internal structure of cross-stratificiation, and the relation of wind systems to these sand forms. Especially lacking were data on criteria that could confidently be used in the recognition of ancient dunes. The common denominator in this publication is eolian sand bodies. Although the book is concerned primarily with desert sand seas, the subject matter is not restricted to deserts; it includes many references to deposits of coastal sand and to sand bodies in humid climates. Nor does the book deal exclusively with dunes, which, according to most definitions, involve mounds or hills. Many references are made to sand sheets, sand stringers, and other types of sand deposits that have no prominent topographic expression. All sand bodies accumulated by the action of wind are discussed. Chapters A-J of this publication are primarily topical. Chapters cover the grain texture, the color, and the structure of modern dunes and other eolian sands. Special treatment is given to the relation of wind data to dune interpretation, the evolution of form in current-deposited sand bodies as determined from experimental studies, and the discriminant analysis technique for differentiating between coastal and inland desert sands. This topical part of the publication also includes an analysis of criteria used in ancient deposits to interpret their eolian genesis and a consideration of economic application of the principles described, including a discussion of potentials and problems

  10. Bioaugmentation of flow-through sand filters

    DEFF Research Database (Denmark)

    Samuelsen, Elin Djurhuus

    for degradation performances in flow-through sand columns, with the aim of identifying a suitable inoculant strain for future environmental applications. Another aim was to identify a suitable genetic marker to monitor phenoxy acid degradation in strain Sphingobium sp. PM2. We were not able to link motility...... and biofilm formation to the strains´ ability to adhere to sand. Nevertheless, a correlation was found between cell surface hydrophobicity and adhesion and overall degradation performances in flow-through sand columns. We identified S phingobium sp. PM2 as a promising inoculant strain, displaying efficient...... MCPA degradation for prolonged periods in flow-through sand columns. In an expression study of catabolic genes with putative roles in phenoxy acid degradation, we observed a marked upregulation of catabolic genes cadA and tfdC upon exposure to MCPA, 2,4-D, dichlorprop and mecoprop in strain PM2, which...

  11. Geotechnical properties of crude oil contaminated sand

    International Nuclear Information System (INIS)

    Puri, V.K.; Das, B.M.; Cook, E.E.; Shin, E.C.

    1994-01-01

    Contamination of soil due to an oil spill influences its subsequent engineering behavior. An investigation was conducted to study the effect of crude oil contamination on compaction characteristics, shear strength, one-dimensional compression, and coefficient of permeability. Water permeability was also determined by using commercial grade motor oils as contaminants. The test results indicate that the compaction characteristics are influenced by oil contamination. The angle of internal friction of sand (based on total stress condition) decreases due to presence of oil within the pore spaces in sand. One dimensional compression characteristics of sand are significantly influenced by oil contamination resulting in a decrease in the value of constrained modulus with increase in the degree of oil contamination compared to the case of dry sand. Water permeability was observed to be a function of the initial viscosity and the degree of saturation due to the contaminating oil

  12. Displacement pile installation effects in sand

    NARCIS (Netherlands)

    Beijer-Lundberg, A.

    2015-01-01

    Installation effects govern the post-installation behaviour of displacement piles in sand. These effects are currently not completely understood. Suitable experimental techniques to model these installation effects include field, laboratory and experimental models. In the current thesis a

  13. Supercritical solvent extraction of oil sand bitumen

    Science.gov (United States)

    Imanbayev, Ye. I.; Ongarbayev, Ye. K.; Tileuberdi, Ye.; Mansurov, Z. A.; Golovko, A. K.; Rudyk, S.

    2017-08-01

    The supercritical solvent extraction of bitumen from oil sand studied with organic solvents. The experiments were performed in autoclave reactor at temperature above 255 °C and pressure 29 atm with stirring for 6 h. The reaction resulted in the formation of coke products with mineral part of oil sands. The remaining products separated into SARA fractions. The properties of the obtained products were studied. The supercritical solvent extraction significantly upgraded extracted natural bitumen.

  14. The influence of sediment transport rate on the development of structure in gravel bed rivers

    Science.gov (United States)

    Ockelford, Annie; Rice, Steve; Powell, Mark; Reid, Ian; Nguyen, Thao; Tate, Nick; Wood, Jo

    2013-04-01

    Although adjustments of surface grain size are known to be strongly influenced by sediment transport rate little work has systematically explored how different transport rates can affect the development of surface structure in gravel bed rivers. Specifically, it has been well established that the transport of mixed sized sediments leads to the development of a coarser surface or armour layer which occurs over larger areas of the gravel bed. Armour layer development is known to moderate overall sediment transport rate as well as being extremely sensitive to changes in applied shear stress. However, during this armouring process a bed is created where, smaller gain scale changes, to the bed surface are also apparent such as the development of pebble clusters and imbricate structures. Although these smaller scale changes affect the overall surface grain size distribution very little their presence has the ability to significantly increase the surface stability and hence alter overall sediment transport rates. Consequently, the interplay between the moderation of transport rate as a function of surface coarsening at a larger scale and moderation of transport rate as a function of the development of structure on the bed surface at the smaller scale is complicated and warrants further investigation. During experiments a unimodal grain size distribution (σg = 1.30, D50 = 8.8mm) was exposed to 3 different levels of constant discharge that produced sediment transport conditions ranging from marginal transport to conditions approaching full mobility of all size fractions. Sediment was re-circulated during the experiments surface grain size distribution bed load and fractional transport rates were measured at a high temporal resolution such that the time evolution of the beds could be fully described. Discussion concentrates on analysing the effects of the evolving bed condition sediment transport rate (capacity) and transported grain size (competence). The outcome of this

  15. Overview--Development of a geodatabase and conceptual model of the hydrogeologic units beneath Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    Science.gov (United States)

    Shah, Sachin D.

    2004-01-01

    Air Force Plant 4 (AFP4) and adjacent Naval Air Station-Joint Reserve Base Carswell Field (NAS–JRB) at Fort Worth, Tex., constitute a contractor-owned, government-operated facility that has been in operation since 1942. Contaminants from the 3,600-acre facility, primarily volatile organic compounds (VOCs) and metals, have entered the ground-water-flow system through leakage from waste-disposal sites and from manufacturing processes. Environmental data collected at AFP4 and NAS–JRB during 1993–2002 created the need for consolidation of the data into a comprehensive temporal and spatial geodatabase. The U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force Aeronautical Systems Center Environmental Management Directorate, developed a comprehensive geodatabase of temporal and spatial environmental data associated with the hydrogeologic units beneath the facility. A three-dimensional conceptual model of the hydrogeologic units integrally linked to the geodatabase was designed concurrently. Three hydrogeologic units—from land surface downward, the alluvial aquifer, the GoodlandWalnut confining unit, and the Paluxy aquifer—compose the subsurface of interest at AFP4 and NAS–JRB. The alluvial aquifer consists primarily of clay and silt with sand and gravel channel deposits that might be interconnected or interfingered. The Goodland-Walnut confining unit directly underlies the alluvial aquifer and consists of limestone, marl, shale, and clay. The Paluxy aquifer is composed of dense mudstone and fine- to coarse-grained sandstone

  16. Spectroscopic characterization of a Nigerian standard sand: Igbokoda sand

    CSIR Research Space (South Africa)

    Ojuri, OO

    2017-01-01

    Full Text Available .45705, 2.28172, 2.23697, 2.12754, 1.98036, 1.81827, 1.54178 and 1.37190 Å confirm the presence of a-quartz crystalline structure in the cample. The calculated unit cell parameters are: a = 4.9133(2) Å, c = 5.4053 Å, V = 113.00 Å. Presence of Si...

  17. Performance of a half-saturated vertical flow wetland packed with volcanic gravel in stormwater treatment.

    Science.gov (United States)

    Chen, Yaoping; Park, Kisoo; Niu, Siping; Kim, Youngchul

    2014-01-01

    A half-saturated pilot-scale wetland planted with Acorus calamus was built to treat urban stormwater. The design comprises a sedimentation tank for pretreatment, and a vertical flow volcanic gravel wetland bed equipped with a recirculation device. Eighteen rainfall events were monitored in 2012. The treatment system achieved total removal efficiencies of 99.4, 81, 50, and 86% for suspended solids, organic matter, nitrogen and phosphorus, respectively, and 29, 68, and 25% for copper, zinc, and lead, respectively, at a 3-day hydraulic residence time. In the wetland bed, the removal of ammonia, total nitrogen, and zinc were improved by recirculation. Plant uptake provided 18% of nitrogen removal and 39% of phosphorus removal. During the experimental stage, only 1.4% of the pore volume in substrate was reduced due to clogging, implying that the wetland can operate without clogging for a relatively long period.

  18. Sampling surface and subsurface particle-size distributions in wadable gravel-and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed monitoring

    Science.gov (United States)

    Kristin Bunte; Steven R. Abt

    2001-01-01

    This document provides guidance for sampling surface and subsurface sediment from wadable gravel-and cobble-bed streams. After a short introduction to streams types and classifications in gravel-bed rivers, the document explains the field and laboratory measurement of particle sizes and the statistical analysis of particle-size distributions. Analysis of particle...

  19. Effect of manufactured sand on the durability characteristics of concrete

    Directory of Open Access Journals (Sweden)

    S. S. SARAVANAN

    2016-12-01

    Full Text Available Concrete is the most sought after material due to increase in construction activities and infrastructural developments. Availability of natural sand is decreasing thereby increase in the cost of construction. In the present work undertaken, an attempt has been made to give an alternative to natural sand. Optimization of replacement of natural sand with manufactured sand in concrete, durability studies such as water absorption, rapid chloride permeability test, sorptivity, acid resistance, alkaline resistance, impact resistance and abrasion resistance of M40 and M50 grades of concrete have been studied with manufactured sand as fine aggregate and compared the results with the conventional sand concrete. The results shows that there is an increase in the durability properties up to 70 % level of replacements of sand with manufactured sand as fine aggregate and for 100 % use of manufactured sand also gives the better durability than the conventional sand concrete.

  20. Studies on various characteristics of concrete structures using crushed sand

    International Nuclear Information System (INIS)

    Mimatsu, Makoto; Sugita, Hideaki; Yonemura, Masataka.

    1985-01-01

    With the recent advances of construction industry, the demands for concrete, hence for aggregate, are rising. The sand as such is in extreme shortage due to the exhaustion of river sand. Under the situation, the recent trends are for the use of crushed sand, i.e. the artificial sand obtained by crushing rocks, which have advantages of stabilized quality and adequate supplies. In building of nuclear power plants requiring large amounts of concrete, the usage of crushed sand is now unavoidable. The following are described : the situation of aggregate in Kyushu. production method of crushed sand and the quality standards, rocks used for crushed stone and sand and the properties, quality survey on crushed sand and the basic tests, characteristic tests of crushed-stone and -sand mixed concrete, the application of crushed sand in structures of the Sendai Nuclear Power Station. (Mori, K.)

  1. Unintended consequences of restoration: loss of riffles and gravel substrates following weir installation.

    Science.gov (United States)

    Salant, Nira L; Schmidt, John C; Budy, Phaedra; Wilcock, Peter R

    2012-10-30

    We used pre- and post-restoration channel surveys of the Donner und Blitzen River, Oregon, to evaluate the effects of grade-control structures on channel morphology and baseflow habitat conditions for native redband trout and other aquatic biota. Six years after installation, we found that the channel had a smaller proportion of riffles and pools and less gravel substrate, combined with an increase in the proportion of flat waters and consolidated clay on the bed surface. Both local scour downstream from weirs and backwater effects upstream from weirs appear to have caused the general flattening and fining of the channel. A direct-step backwater calculation indicates that backwaters extended to the upstream weir at both low and high flows, creating long sections of flat water separated by short, steep drops. Despite backwater effects, a comparison of longitudinal profiles before and six years after weir installation showed bed erosion downstream of nearly all weirs, likely a consequence of the cohesive clay material that dominates the channel bed and banks. A deep inner channel reflects the cohesive nature of the clay and the mechanisms of abrasion, and indicates that sediment load is low relative to the transport capacity of the flow. Unfortunately, weirs were problematic in this system because of the cohesive clay substrate, limited sediment supply, and low channel gradient. Although deeper flows due to backwaters might be more favorable for resident trout, less gravel and fewer riffles are likely to negatively impact trout spawning habitat, macroinvertebrate communities, and biofilm productivity. Our results demonstrate the potential limitations of a single-feature approach to restoration that may be ineffective for a given geomorphic context and may overlook other aspects of the ecosystem. We highlight the need to incorporate geomorphic characteristics of a system into project design and predictions of system response. Copyright © 2012 Elsevier Ltd. All rights

  2. Temporal and spatial variability in thalweg profiles of a gravel-bed river

    Science.gov (United States)

    Madej, Mary Ann

    1999-01-01

    This study used successive longitudinal thalweg profiles in gravel-bed rivers to monitor changes in bed topography following floods and associated large sediment inputs. Variations in channel bed elevations, distributions of residual water depths, percentage of channel length occupied by riffles, and a spatial autocorrelation coefficient (Moran's I) were used to quantify changes in morphological diversity and spatial structure in Redwood Creek basin, northwestern California. Bed topography in Redwood Creek and its major tributaries consists primarily of a series of pools and riffles. The size, frequency and spatial distribution of the pools and riffles have changed significantly during the past 20 years. Following large floods and high sediment input in Redwood Creek and its tributaries in 1975, variation in channel bed elevations was low and the percentage of the channel length occupied by riffles was high. Over the next 20 years, variation in bed elevations increased while the length of channel occupied by riffles decreased. An index [(standard deviation of residual water depth/bankfull depth) × 100] was developed to compare variations in bed elevation over a range of stream sizes, with a higher index being indicative of greater morphological diversity. Spatial autocorrelation in the bed elevation data was apparent at both fine and coarse scales in many of the thalweg profiles and the observed spatial pattern of bed elevations was found to be related to the dominant channel material and the time since disturbance. River reaches in which forced pools dominated, and in which large woody debris and bed particles could not be easily mobilized, exhibited a random distribution of bed elevations. In contrast, in reaches where alternate bars dominated, and both wood and gravel were readily transported, regularly spaced bed topography developed at a spacing that increased with time since disturbance. This pattern of regularly spaced bed features was reversed

  3. Comparison of Machine Learning methods for incipient motion in gravel bed rivers

    Science.gov (United States)

    Valyrakis, Manousos

    2013-04-01

    Soil erosion and sediment transport of natural gravel bed streams are important processes which affect both the morphology as well as the ecology of earth's surface. For gravel bed rivers at near incipient flow conditions, particle entrainment dynamics are highly intermittent. This contribution reviews the use of modern Machine Learning (ML) methods implemented for short term prediction of entrainment instances of individual grains exposed in fully developed near boundary turbulent flows. Results obtained by network architectures of variable complexity based on two different ML methods namely the Artificial Neural Network (ANN) and the Adaptive Neuro-Fuzzy Inference System (ANFIS) are compared in terms of different error and performance indices, computational efficiency and complexity as well as predictive accuracy and forecast ability. Different model architectures are trained and tested with experimental time series obtained from mobile particle flume experiments. The experimental setup consists of a Laser Doppler Velocimeter (LDV) and a laser optics system, which acquire data for the instantaneous flow and particle response respectively, synchronously. The first is used to record the flow velocity components directly upstream of the test particle, while the later tracks the particle's displacements. The lengthy experimental data sets (millions of data points) are split into the training and validation subsets used to perform the corresponding learning and testing of the models. It is demonstrated that the ANFIS hybrid model, which is based on neural learning and fuzzy inference principles, better predicts the critical flow conditions above which sediment transport is initiated. In addition, it is illustrated that empirical knowledge can be extracted, validating the theoretical assumption that particle ejections occur due to energetic turbulent flow events. Such a tool may find application in management and regulation of stream flows downstream of dams for stream

  4. Rapid Sand Filtration for Best Practical Treatment of Domestic Wastewater Stabilization Pond Effluent

    Science.gov (United States)

    Boatright, D. T.; Lawrence, C. H.

    1977-01-01

    The technical and economic feasibility of constructing and operating a rapid sand filtration sewage treatment system as an adjunct to a waste water stabilization pond is investigated. The study concludes that such units are within the technical and economic constraints of a small community and comply with the EPA criteria. (BT)

  5. Long-term sand supply to Coachella Valley Fringe-toed Lizard Habitat in the Northern Coachella Valley, California

    Science.gov (United States)

    Griffiths, Peter G.; Webb, Robert H.; Lancaster, Nicholas; Kaehler, Charles A.; Lundstrom, Scott C.

    2002-01-01

    The Coachella Valley fringe-toed lizard (Uma inornata) is a federally listed threatened species that inhabits active sand dunes in the vicinity of Palm Springs, California. The Whitewater Floodplain and Willow Hole Reserves provide some of the primary remaining habitat for this species. The sediment-delivery system that creates these active sand dunes consists of fluvial depositional areas fed episodically by ephemeral streams. Finer fluvial sediments (typically sand size and finer) are mobilized in a largely unidirectional wind field associated with strong westerly winds through San Gorgonio Pass. The fluvial depositional areas are primarily associated with floodplains of the Whitewater?San Gorgonio Rivers and Mission Creek?Morongo Wash; other small drainages also contribute fluvial sediment to the eolian system. The eolian dunes are transitory as a result of unidirectional sand movement from the depositional areas, which are recharged with fine-grained sediment only during episodic floods that typically occur during El Ni?o years. Eolian sand moves primarily from west to east through the study area; the period of maximum eolian activity is April through June. Wind speed varies diurnally, with maximum velocities typically occurring during the afternoon. Development of alluvial fans, alteration of stream channels by channelization, in-stream gravel mining, and construction of infiltration galleries were thought to reduce the amount of fluvial sediment reaching the depositional areas upwind of Uma habitat. Also, the presence of roadways, railroads, and housing developments was thought to disrupt or redirect eolian sand movement. Most of the sediment yield to the fluvial system is generated in higher elevation areas with little or no development, and sediment yield is affected primarily by climatic fluctuations and rural land use, particularly livestock grazing and wildfire. Channelization benefits sediment delivery to the depositional plains upwind of the reserves

  6. Utilisation of Sand from Kaolin Washing for the Manufacture of Alkali-activated Artificial Sandstone

    Science.gov (United States)

    Vavro, Martin; Vavro, Leona; Mec, Pavel; Soucek, Kamil; Pticen, Frantisek; Reiterman, Pavel

    2017-04-01

    Sandstones represent a traditional natural stones which are widely used in Czech architecture and sculpture over a long time. Thanks to their relatively easy workability, sandstones provide a wide range of stone products and also represent a popular material for architectural and sculptural purposes. In the field of restoration of artworks, they are therefore often used for manufacturing stone statue copies originally made from the same or similar type of stone. Despite a relatively common and varied occurrence of natural sandstones, the method of the artificial stone facsimiles creation in the form of various cast elements is also often applied in restoration practice. The history of application of artificial stones in civil engineering and architecture goes back to the ancient times, i.e. to Roman antiquity and possibly up to the time of ancient Egypt. The lack of appropriate natural rock, suitable in the view of colour, grain size or texture is the main reason of manufacturing copies based on synthetic mixtures. The other reason is high financial costs to create a sculpture copy from natural materials. Mixtures made from white and/or grey cements, sands, carefully selected crushed stone or well graded natural gravels, and mineral coloring pigments or mixtures with acrylate, polyester, and epoxy resins binder are the most frequently used artificial materials for cast stone manufacturing. This paper aims to bring information about composition and properties of artificial sandstones made from alkali-activated binder mixtures based on metakaolin and granulated blast furnace slag. The filler of this artificial stone is represented by fine-grained sand generated during kaolin wet processing. Used sand is mainly formed by quartz, feldspars, micas (muscovite > biotite), residual kaolin, and to a lesser extent also by Fe oxyhydroxides ("limonite"), titanium dioxide mineral (probably anatase), and carbonate mineral unidentified in detail. Annual Czech production of this

  7. Flow structure through pool-riffle sequences and a conceptual model for their sustainability in gravel-bed rivers

    Science.gov (United States)

    D. Caamano; P. Goodwin; J. M. Buffington

    2010-01-01

    Detailed field measurements and simulations of three-dimensional flow structure were used to develop a conceptual model to explain the sustainability of self-formed pool-riffle sequences in gravel-bed rivers. The analysis was conducted at the Red River Wildlife Management Area in Idaho, USA, and enabled characterization of the flow structure through two consecutive...

  8. Bed stability in unconfined gravel bed mountain streams: With implications for salmon spawning viability in future climates

    Science.gov (United States)

    Jim McKean; Daniele Tonina

    2013-01-01

    Incubating eggs of autumn-spawning Chinook salmon (Oncorhynchus tshawytscha) could be at risk of midwinter high flows and substrate scour in a changing climate. A high-spatial-resolution multidimensional hydrodynamics model was used to assess the degree of scour risk in low-gradient unconfined gravel bed channels that are the favored environment for autumn-spawning...

  9. Removal of Zn(II) from electroplating effluent using yeast biofilm formed on gravels: batch and column studies

    Science.gov (United States)

    2014-01-01

    Background Present study deals with the removal of Zn(II) ions from effluent using yeast biofilm formed on gravels. Methods The biofilm forming ability of Candida rugosa and Cryptococcus laurentii was evaluated using XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay and monitored by scanning electron microscopy (SEM), and Confocal laser scanning microscopy (CLSM). Copious amount of extracellular polymeric substances (EPS) produced by yeast species was quantified and characterized by Fourier transform infrared spectroscopy (FT-IR). Results Yeast biofilm formed on gravels by C. rugosa and C. laurentii showed 88% and 74.2% removal of Zn(II) ions respectively in batch mode. In column mode, removal of Zn(II) ions from real effluent was found to be 95.29% by C. rugosa biofilm formed on gravels. Conclusion The results of the present study showed that there is a scope to develop a cost effective method for the efficient removal of Zn(II) from effluent using gravels coated with yeast biofilm. PMID:24397917

  10. The Influence of Baker Bay and Sand Island on Circulations in the Mouth of the Columbia River

    Science.gov (United States)

    2014-06-01

    Island is a good example of a dredge spoils area protected by a pile dike system. Without the stabilizing effect of the Sand Island pile dikes, the...Sand Island) and pile dikes, and the effects of these features on adjacent water masses in the lower Columbia River. 4 THIS PAGE INTENTIONALLY...each drifter using Velcro and nylon straps with pinch buckles. Each case contained a 1-Hz sampling internally-logging GT-31 handheld GPS unit for

  11. Nuclear energy in the oils sands

    International Nuclear Information System (INIS)

    Arsenault, J.E.

    2014-01-01

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  12. Nuclear energy in the oils sands

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, J.E.

    2014-09-15

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  13. Comparison between predicted and observed sand waves and sand banks in the North Sea

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; van den Brink, G.M.

    2001-01-01

    For the first time a prediction model of regular morphological patterns on the seabed was tested against observations of sand wave and sand bank occurrence in the entire North Sea. The model, which originates from first physical principles, predicts this occurrence via two dimensionless parameters

  14. Replicating the microbial community and water quality performance of full-scale slow sand filters in laboratory-scale filters.

    Science.gov (United States)

    Haig, Sarah-Jane; Quince, Christopher; Davies, Robert L; Dorea, Caetano C; Collins, Gavin

    2014-09-15

    Previous laboratory-scale studies to characterise the functional microbial ecology of slow sand filters have suffered from methodological limitations that could compromise their relevance to full-scale systems. Therefore, to ascertain if laboratory-scale slow sand filters (L-SSFs) can replicate the microbial community and water quality production of industrially operated full-scale slow sand filters (I-SSFs), eight cylindrical L-SSFs were constructed and were used to treat water from the same source as the I-SSFs. Half of the L-SSFs sand beds were composed of sterilized sand (sterile) from the industrial filters and the other half with sand taken directly from the same industrial filter (non-sterile). All filters were operated for 10 weeks, with the microbial community and water quality parameters sampled and analysed weekly. To characterize the microbial community phyla-specific qPCR assays and 454 pyrosequencing of the 16S rRNA gene were used in conjunction with an array of statistical techniques. The results demonstrate that it is possible to mimic both the water quality production and the structure of the microbial community of full-scale filters in the laboratory - at all levels of taxonomic classification except OTU - thus allowing comparison of LSSF experiments with full-scale units. Further, it was found that the sand type composing the filter bed (non-sterile or sterile), the water quality produced, the age of the filters and the depth of sand samples were all significant factors in explaining observed differences in the structure of the microbial consortia. This study is the first to the authors' knowledge that demonstrates that scaled-down slow sand filters can accurately reproduce the water quality and microbial consortia of full-scale slow sand filters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Heavy mineral concentration from oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Chachula, F.; Erasmus, N. [Titanium Corp. Inc., Regina, SK (Canada)

    2008-07-01

    This presentation described a unique technique to recover heavy minerals contained in the froth treatment tailings produced by oil sand mining extraction operations in Fort McMurray, Alberta. In an effort to process waste material into valuable products, Titanium Corporation is developing technology to recover heavy minerals, primarily zircon, and a portion of bitumen contained in the final stage of bitumen processing. The process technology is being developed to apply to all mined oil sands operations in the Fort McMurray region. In 2004, Titanium Corporation commissioned a pilot research facility at the Saskatchewan Research Council to test dry oil sands tailings. In 2005, a bulk sampling pilot plant was connected to the fresh oil sands tailings pipeline on-site in Fort McMurray, where washed sands containing heavy minerals were processed at a pilot facility. The mineral content in both deposited tailings and fresh pipeline tailings was assessed. Analysis of fresh tailings on a daily basis identified a constant proportion of zircon and higher levels of associated bitumen compared with the material in the deposited tailings. The process flow sheet design was then modified to remove bitumen from the heavy minerals and concentrate the minerals. A newly modified flotation process was shown to be a viable processing route to recover the heavy minerals from froth treatment tailings. 8 refs., 9 tabs., 12 figs.

  16. A Improved Seabed Surface Sand Sampling Device

    Science.gov (United States)

    Luo, X.

    2017-12-01

    In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

  17. Sand filter clogging by septic tank effluent.

    Science.gov (United States)

    Spychała, M; Błazejewski, R

    2003-01-01

    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.

  18. The behavior of gaseous iodine in sand

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1974-01-01

    Radioactive iodine gas was passed through 10 different sands collected at rivers and hills. The relation between the amount of the loaded gas and the amount of adsorbed gas was determined at room temperature, 50 -- 60 0 C, and 90 -- 100 0 C under humidity of 2 sand. This amount was about 1 -- 3 times as much as that of monomolecular membrane adsorption, 0.2 -- 0.3 μg/cm 2 . The decrease of adsorption amount that accompanies the increase of humidity is attributable to the decrease of effective surface area of sand due to the presence of water. The transport of iodine in sand was studied by passing gaseous iodine through a glass tubing packed with sand. The distribution in the flow direction of iodine indicated that the ease of desorption depends upon the situation of adsorption. Easily desorbed case was named Henry type adsorption. Hardly desorbed case was named absorption type. Discussion is made on experimental results. (Fukutomi, T.)

  19. Mitigating in situ oil sands carbon costs

    Energy Technology Data Exchange (ETDEWEB)

    Theriault, D.J.; Peterson, J. [Laricina Energy Ltd., Calgary, AB (Canada); Heinrichs, H. [Canadian Chemical Technology Inc., Calgary, AB (Canada)

    2008-10-15

    Carbon capture and sequestration is a complex problem with a variety of dimensions that need to be considered. The political, social, and regulatory pressures are forcing carbon costs on the oil sands industry in an effort to reduce the carbon footprint of oil sands operations. This paper reviewed the political, social, and regulatory pressures and obligations for the in-situ oil sands industry. It presented the views and insights of Laricina Energy on the carbon challenge. It also described the initiatives that Laricina Energy is taking to manage these imperatives and outlined the challenges the industry is facing. The purpose of the paper was to encourage dialogue and collaboration by the oil sands industry. The paper also described the dimensions of the carbon problem and how the industry can contribute to a solution. Last, the paper reviewed the parameters of carbon dioxide or greenhouse gas containment and storage issues. It was concluded that the regulatory and policy requirements need to be clarified so that industry understands the new business landscape as well as the requirements that influence the economics of in-situ oil sands development. 7 refs., 7 figs.

  20. Performance of sand filters for the separations areas at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    Orth, D.A.; Sykes, G.H.; McKibben, J.M.

    1981-01-01

    Two new large sand filters, 30.5 by 100 m, were constructed and put into service at the Savannah River Plant (SRP) in 1975 and 1976. These units were designed to provide final filtration of process air - one for each of the two separations areas. Eventual flow will be 4950 m 3 /min (205,000 scfm) on each unit when all facilities are connected. They were built as replacements for the original sand filters that began operation in 1954 and 1955. The new filters have been operated in parallel with the old units following partial failure of the old units from acid attack and erosion of the concrete support structure for the sand beds. The design of the new units was based on extensive tests at SRP on characteristics of different sands. The performance of the new filters meets criteria for pressure drop, flow capacity, and efficiency. The efficiencies measured by DOP test are greater than 99.98%. Parallel operation reduces air velocity through the beds, which increases efficiency. A characteristic of sand filter performance has been low apparent efficiency at low input; efficiency increases as the activity input rises. This is attributed to a small entrainment release from the large amount of activity already sorbed on the filter; this release controls and lowers the calculated efficiency at low input. An analysis of efficiency as a function of input activity projects efficiencies greater than 99.99% for large inputs that might be characteristic of large internal accidents. The data indicate that DOP efficiencies can be used in hazards analyses to determine accident consequences. Routine evaluation of filter releases can be used for surveillance to establish that performance is normal at other times

  1. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  2. Differential effects of a local industrial sand lance fishery on seabird breeding performance

    DEFF Research Database (Denmark)

    Frederiksen, M.; Jensen, Henrik; Daunt, F.

    2008-01-01

    fluctuations. We evaluated the effects of an industrial sand lance (Ammodytes marinus) fishery off the North Sea coast of the United Kingdom, which has been opened and closed in a quasi-experimental fashion, on sand-lance-dependent breeding seabirds. Controlling for environmental variation ( sea surface...... tridactyla), but not for four diving species. Analyzing Kittiwake data from 12 colonies inside and outside the closure zone in a replicated before-after control impact design, we again found that breeding productivity was significantly depressed in the closure zone when the fishery was active, whereas...

  3. Differential effects of a local industrial sand lance fishery on seabird breeding performance

    DEFF Research Database (Denmark)

    Frederiksen, M.; Jensen, Henrik; Daunt, F.

    2008-01-01

    fluctuations. We evaluated the effects of an industrial sand lance (Ammodytes marinus) fishery off the North Sea coast of the United Kingdom, which has been opened and closed in a quasi-experimental fashion, on sand-lance-dependent breeding seabirds. Controlling for environmental variation ( sea surface...... or to the fact that only one study colony in the control zone was exposed to high fishery effort within the typical foraging range of Kittiwakes during the breeding season. The strong impact on Kittiwakes, but not on diving species, could result from ( 1) inherently high sensitivity to reduced prey availability...

  4. Characterization for capillary barriers effects in a sand box test using time-lapsed GPR measurements

    Science.gov (United States)

    Kuroda, S.; Ishii, N.; Morii, T.

    2017-12-01

    Capillary barriers have been known as the method to protect subsurface regions against infiltration from soil surface. It is caused by essentially heterogeneous structure in permeability or soil physical property and produce non-uniform infiltration process then, in order to estimate the actual situation of the capillary barrier effect, the site-characterization with imaging technique like geophysical prospecting is effective. In this study, we examine the applicability of GPR to characterization for capillary barriers. We built a sand box with 90x340x90cm in which a thin high-permeable gravel layer was embedded as a capillary barrier. We conducted an infiltration test in the sand box using porous tube array for irrigation. It is expected to lead to non-uniform flow of soil water induced by capillary barrier effects. We monitored this process by various types of GPR measurements, including time-lapsed common offset profiling (COP) with multi- frequency antenna and transmission measurements like cross-borehole radar. At first, we conducted GPR common-offset survey. It could show the depth of capillary barrier in sand box. After that we conducted the infiltration test and GPR monitoring for infiltration process. GPR profiles can detect the wetting front and estimate water content change in the soil layer above the capillary barrier. From spatial change in these results we can estimate the effect of capillary barrier and the zone where the break through occur or not. Based on these results, we will discuss the applicability of GPR for monitoring the phenomena around the capillary barrier of soil. At first, we conducted GPR common-offset survey. It could show the depth of capillary barrier in sand box. After that we conducted the infiltration test and GPR monitoring for infiltration process. GPR profiles can detect the wetting front and estimate water content change in the soil layer above the capillary barrier. From spatial change in these results we can estimate the

  5. Test work of sand compaction pile method on coal ash soil foundation. Sekitanbai jiban ni okeru sand compaction pile koho no shiken seko

    Energy Technology Data Exchange (ETDEWEB)

    Goto, K.; Maeda, S.; Shibata, T. (The Kansai Electric Power Co. Inc., Osaka (Japan))

    1992-01-25

    As an electric power supply source after the 1990 {prime}s, Nos. 5 and 6 units are additionally being constructed by Kansai Electric Power in its Himeji Power Station No.1 which is an exclusively LNG burning power station. The additional construction site of those units is of soil foundation reclaimed with coal ash which was used residual product in the existing No.1 through No.4 units. As a result of soil foundation survey, the coal ash layer and sand layer were known to be of material to be possibly liquidized at the time of earthquake. As measures against the liquidization, application was basically made of a sand compaction pile (SCP) method which is economical and abundant in record. However, that method was so short of record in the coal ash layer that its evaluation was difficult in soil reforming effect. Therefore, its applicability was evaluated by a work test on the site, which resulted in a confirmation that the coal ash as well as the sand can be sufficiently reformed by the SCP method. Started in September, 1991, the additional construction of Nos. 5 and 6 units in Himeji Power Station No.1 uses a 1.5m pitch SCP method to reform the soil foundation. 3 refs., 10 figs., 1 tab.

  6. Sand transport, erosion and granular electrification

    DEFF Research Database (Denmark)

    Merrison, J.P.

    2012-01-01

    is expanding our current understanding and outline the areas of advancement needed in the future. Presentation is made of current models for wind driven detachment/entrainment and the transport rates of sand and dust, including the effects of contact induced grain electrification. This ubiquitous phenomenon...... can affect grain transport through the generation of intense electric fields and processes of electrostatic assembly. Importantly the transport of sand is characterized by saltation, which is known to be an active process for erosion and therefore a source for dust and sand formation. Using novel...... erosion simulation techniques the link between grain transport rates and erosion rates has been quantified. Furthermore this can be linked to production rates for dust and has been associated with chemical and mineral alteration through a process of mechanical activation of fractured surfaces. This work...

  7. Thermoluminescent dosimetric properties of Descalvado sand

    International Nuclear Information System (INIS)

    Teixeira, M.I.; Caldas, L.V.E.

    2006-01-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ( 60 Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  8. Development tendencies of moulding and core sands

    Directory of Open Access Journals (Sweden)

    Stanislaw M. Dobosz1

    2011-11-01

    Full Text Available Further development of the technology for making moulding and core sands will be strictly limited by tough requirements due to protection of the natural environment. These tendencies are becoming more and more tense, so that we will reach a point when even processes, that from technological point of view fulfill high requirements of the foundry industry, must be replaced by more ecologically-friendly solutions. Hence, technologies using synthetic resins as binding materials will be limited. This paper presents some predictable development tendencies of moulding and core sands. The increasing role of inorganic substances will be noticed, including silicate binders with significantly improved properties, such as improved knock-out property or higher reclamation strength. Other interesting solutions might also be moulding sands bonded by geo-polymers and phosphate binders or salts and also binders based on degradable biopolymers. These tendencies and the usefulness of these binders are put forward in this paper.

  9. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  10. Habitat analysis of North American sand flies near veterans returning from leishmania-endemic war zones

    Directory of Open Access Journals (Sweden)

    Keep Lisa

    2008-12-01

    Full Text Available Abstract Background Nearly 1300 cases of leishmaniasis have been identified in American military personnel deployed to Iraq and Afghanistan. The symptoms of this disease can range from a mild, self-limiting cutaneous infection to a deadly visceral infection and are not prevented by chemoprophylaxis or immunization. Effective treatments, however, are available. The disease-causing parasite is spread through the bite of the female sand fly. Although the disease occurs in both the Old World and the New World, the parasite species differ between the hemispheres. The large number of cases in military veterans has caused some concern that Old World, temperate-adapted parasite species could be introduced into the native sand fly populations of American military facilities where veterans of the current conflicts return following their deployments. This paper reports part of a larger study to analyze the risk of such an accidental importation. Four potential habitats on two large Army facilities in the Southeast United States were surveyed to determine relative sand fly density. The National Land Cover Map was used to provide sand fly density prediction maps by habitat. Results Sand fly density was significantly higher in deciduous forest and even higher at the interface between forest and open grassland. The evergreen forest and agricultural fields supported very low densities. On Fort Campbell, KY, the percentage of land covered by suitable habitat was very high. A sand fly density prediction map identified large tracts of land where infected individuals would be at higher risk of exposure to sand fly bites, resulting in an increased risk of introducing the parasite to a native insect population. On Fort Bragg, NC, however, commercial farming of long leaf pine reduced the percentage of the land covered in vegetation suitable for the support of sand flies. The risk of introducing an exotic Leishmania spp. on Fort Bragg, therefore, is considered to be

  11. A Threshold Continuum for Aeolian Sand Transport

    Science.gov (United States)

    Swann, C.; Ewing, R. C.; Sherman, D. J.

    2015-12-01

    The threshold of motion for aeolian sand transport marks the initial entrainment of sand particles by the force of the wind. This is typically defined and modeled as a singular wind speed for a given grain size and is based on field and laboratory experimental data. However, the definition of threshold varies significantly between these empirical models, largely because the definition is based on visual-observations of initial grain movement. For example, in his seminal experiments, Bagnold defined threshold of motion when he observed that 100% of the bed was in motion. Others have used 50% and lesser values. Differences in threshold models, in turn, result is large errors in predicting the fluxes associated with sand and dust transport. Here we use a wind tunnel and novel sediment trap to capture the fractions of sand in creep, reptation and saltation at Earth and Mars pressures and show that the threshold of motion for aeolian sand transport is best defined as a continuum in which grains progress through stages defined by the proportion of grains in creep and saltation. We propose the use of scale dependent thresholds modeled by distinct probability distribution functions that differentiate the threshold based on micro to macro scale applications. For example, a geologic timescale application corresponds to a threshold when 100% of the bed in motion whereas a sub-second application corresponds to a threshold when a single particle is set in motion. We provide quantitative measurements (number and mode of particle movement) corresponding to visual observations, percent of bed in motion and degrees of transport intermittency for Earth and Mars. Understanding transport as a continuum provides a basis for revaluating sand transport thresholds on Earth, Mars and Titan.

  12. Gasification of oil sand coke: review

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. [IMAF Group, Ottawa, ON (Canada)

    1998-08-01

    The production of synthetic crude from the tar sands in Western Canada has been steadily increasing. Most of the delayed coke produced by Suncor is combusted on site, whereas all fluid coke produced by Syncrude is stockpiled.The database on the chemical and physical properties of the oil sand coke, including the composition and fusion properties of the mineral matter, has been established. The reactivity of the coke was determined by oxygen chemisorption, fixed bed and fluid bed bench scale gasification and pilot plant gasification. The reactivity of the oil sand coke for gasification is rather low and comparable to high rank coals, such as anthracite. Slurrability tests revealed that a solid concentration in water, approaching 70 wt%, can be achieved. Gasification is the front runner among clean technologies for the conversion of carbonaceous solids to useful products. Several commercial gasifiers are available to cover the wide range of severity. Because of the low reactivity of oil sands coke, high severity conditions are required to achieve high gasification conversion. Such conditions can be attained in entrained bed gasifiers. Gasifiers employing both dry and slurry feeding systems are suitable. A high efficiency, low SO{sub x} and NO{sub x} emissions, as well as a low solid waste production are among the key advantages of the gasification technology compared with thecompeting technologies. Commercial gasification of oil sands coke is delayed because of the availability of natural gas on the site of the upgrading plants. Potential for the transportation of the oil sand coke to USA for electricity generation using the integrated gasification combined-cycle (IGCC) technology was evaluated. 27 refs., 17 figs., 9 tabs.

  13. Using Pneumatics to Perform Laboratory Hydraulic Conductivity Tests on Gravel with Underdamped Responses

    Science.gov (United States)

    Judge, A. I.

    2011-12-01

    A permeameter has been designed and built to perform laboratory hydraulic conductivity tests on various kinds of gravel samples with hydraulic conductivity values ranging from 0.1 to 1 m/s. The tests are commenced by applying 200 Pa of pneumatic pressure to the free surface of the water column in a riser connected above a cylinder that holds large gravel specimens. This setup forms a permeameter specially designed for these tests which is placed in a barrel filled with water, which acts as a reservoir. The applied pressure depresses the free surface in the riser 2 cm until it is instantly released by opening a ball valve. The water then flows through the base of the cylinder and the specimen like a falling head test, but the water level oscillates about the static value. The water pressure and the applied air pressure in the riser are measured with vented pressure transducers at 100 Hz. The change in diameter lowers the damping frequency of the fluctuations of the water level in the riser, which allows for underdamped responses to be observed for all tests. The results of tests without this diameter change would otherwise be a series of critically damped responses with only one or two oscillations that dampen within seconds and cannot be evaluated with equations for the falling head test. The underdamped responses oscillate about the static value at about 1 Hz and are very sensitive to the hydraulic conductivity of all the soils tested. These fluctuations are also very sensitive to the inertia and friction in the permeameter that are calculated considering the geometry of the permeameter and verified experimentally. Several gravel specimens of various shapes and sizes are tested that show distinct differences in water level fluctuations. The friction of the system is determined by calibrating the model with the results of tests performed where the cylinder had no soil in it. The calculation of the inertia in the response of the water column for the typical testing

  14. On the Size Distribution of Sand

    DEFF Research Database (Denmark)

    Sørensen, Michael

    2016-01-01

    A model is presented of the development of the size distribution of sand while it is transported from a source to a deposit. The model provides a possible explanation of the log-hyperbolic shape that is frequently found in unimodal grain size distributions in natural sand deposits, as pointed out......-distribution, by taking into account that individual grains do not have the same travel time from the source to the deposit. The travel time is assumed to be random so that the wear on the individual grains vary randomly. The model provides an interpretation of the parameters of the NIG-distribution, and relates the mean...

  15. Creating fluid injectivity in tar sands formations

    Science.gov (United States)

    Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan

    2010-06-08

    Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons are produced from the portion.

  16. Log-inject-log in sand consolidation

    International Nuclear Information System (INIS)

    Murphy, R.P.; Spurlock, J.W.

    1977-01-01

    A method is described for gathering information for the determination of the adequacy of placement of sand consolidating plastic for sand control in oil and gas wells. The method uses a high neutron cross-section tracer which becomes part of the plastic and uses pulsed neutron logging before and after injection of the plastic. Preferably, the method uses lithium, boron, indium, and/or cadmium tracers. Boron oxide is especially useful and can be dissolved in alcohol and mixed with the plastic ingredients

  17. Oil sand synfuel production using nuclear energy

    International Nuclear Information System (INIS)

    Barnert, H.

    1984-10-01

    The importance of oil sand as a primary energy carrier is illustrated. The oil sand mining project 'synfuel' in Fort McMurray, Alberta, Canada, is described. On the basis of a layout of an In-situ-process different possibilities of introducing nuclear energy to the process are described. This leads to an increase of the product yield, leading finally to a doubling of the energy output compared to the reference layout. The introduction of nuclear energy contributes to the reduction of emissions, in particular to the emission of carbon dioxide in the conversion process. (orig.)

  18. Permeability Tests on Silkeborg Sand No. 0000

    DEFF Research Database (Denmark)

    Lund, Willy; Jakobsen, Kim Parsberg

    on the characteristics of the soil matrix, the permeability is determined for different void ratios. All tests are performed on reconstituted specimens of Silkeborg Sand No. 0000. The permeability is determined by use of a falling head apparatus. The apparatus, test procedures and the analysis method are described......The flow through porous media plays an important role in various engineering disciplines, as for example in ground water hydrology and soil mechanics. In the present study the permeability is determined for a fine, saturated sand. As the flow through a porous media strongly depends...

  19. Permeability Tests on Eastern Scheldt Sand

    DEFF Research Database (Denmark)

    Jakobsen, Kim Parsberg

    on the characteristics of the soil matrix, the permeability is determined for different void ratios. All tests are performed on reconstituted specimens of Eastern Scheldt Sand. The permeability is determined by use of a falling head apparatus. Finally the test results are briefly summarised and a relationship between......The flow through porous media plays an important role in various engineering disciplines, as for example in ground water hydrology and soil mechanics. In the present study the permeability is determined for a fine, saturated sand. As the flow through a porous media strongly depends...

  20. Sand control systems used in completing wells

    Directory of Open Access Journals (Sweden)

    Gabriel Wittenberger

    2005-12-01

    Full Text Available Expandable Tubular Technology is transforming the face of well completion and construction. This technology provides: a substantially higher hydrocarbon production rates from the reservoir, a reduced well drilling and construction costs, new possibilities for previously unreachable or uneconomic reservoirs, and step a change towards the single diameter well. ESS (Expandable Sand Screen has an unrivalled performance worldwide for delivering a reliable sand control in a wide range of applications. Well costs typically cut by over 20 %, and the productivity increases up to 70 %.

  1. Integrated sulphur management : gas, oil sands, reclamation and the challenges of fluctuating demand

    International Nuclear Information System (INIS)

    Pineau, R.

    2009-01-01

    International Commodities Export Corporation is a privately held company that provides fully integrated service offerings to add maximum value in designing, building, owning, and operating sulphur assets. The company also offers in-house, engineering, procurement and project management, as well as supply management, transportation and distribution services. It also has expertise in marine transportation. This presentation discussed integrated sulphur management, with particular focus on gas, oil sands, reclamation and the challenges of fluctuating demand. The presentation provided an overview of the sulphur market and oil sands sulphur. Key considerations for oil sands producers were also presented. The challenges of fluctuating demand include price and volume considerations; logistics; geography and distance to market; export/offshore versus domestic/United States; seasonal considerations; and an inelastic sulphur market. The presentation concluded with a status update of ICEC's initiative and the advantages of Prince Rupert, an economically viable export infrastructure to producers without onsite forming facilities. figs

  2. Experimental perforation of tubing with a hydraulic sand jet

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Yu V

    1970-01-01

    A series of field tests has shown that perforation with a hydraulic sand jet improves the quality of well completion. The sand jet does not crack the cement sheath or the casing, and the perforations are larger and deeper than perforations formed by explosive charges. Fluid circulation during sand jet perforation can safely be stopped for at least 10 min. Water containing a surfactant can be used as a sand carrier. Sand jet perforation allows successful completion of wells cased by 2 tubing strings. Sand jet perforation can be used to clean the borehole well and to remove foreign objects from the well.

  3. MouldingSandDB – a modern database storing moulding sands properties research results

    Directory of Open Access Journals (Sweden)

    J. Jakubski

    2011-01-01

    Full Text Available The complexity of foundry processes requires the use of modern, advanced IT tools for optimization, storage and analysis of t echnicaldata. Properties of moulding and core sands that are collected in research laboratories, manufacturers, and finally in the foundries, are not in use later on. It seems important to create a database that will allow to use the results stored, along with the possibility of searching according to set criteria, adjusted to casting practice. This paper presents part of the database named „MouldingSandDB”, which allows to collect and search data for synthetic moulding sands.

  4. Groundwater monitoring for remedial investigation in the Oriskany-Whitestown Sand Plain, Oneida County, New York

    International Nuclear Information System (INIS)

    Kewer, R.P.; Birckhead, E.F.

    1992-01-01

    The 50-acre Whitestown Landfill is listed by NYSDEC as a Class 2 inactive hazardous waste disposal site. During Remedial Investigations, a 23-well groundwater monitoring system was installed, exploring Wisconsin age glaciofluvial deposits of the Oriskany-Whitestown sand plain. These were described in the late 19th century as deltaic sediments deposited in a proglacial lake. However, no recent studies and only limited subsurface data were available, prompting a two-phase installation program. The landfill is located above steep bluffs 70 feet above the Mohawk River and Oriskany Creek valleys. Beneath the landfill, Phase I identified a gradational sequence of coarse to fine deltaic sediments with glacial till. This sequence was partly eroded and overlain by alluvium and colluvium in the valleys. The landfill was constructed on surficial deposits of coarse fluviodeltaic gravel. These were underlain by deltaic deposits grading from sand to silt with depth, the lower silts comprising the uppermost aquifer. The silts made identification of the water table difficult during drilling and caused problems in meeting a stringent development criterion for turbidity. Phase I found that the saturated zone, up to 50 feet thick, is perched on glaciolacustrine clays and, locally, tills, which were the lower boundary of the system investigated. Partly influenced by the clays, groundwater and contaminant movement was to the adjoining valley, causing off-site impacts in the shallow alluvial/colluvial aquifer. Therefore, Phase 11 focused on characterizing flow and groundwater quality in the discharge area, particularly with respect to an adjacent residence and wetlands. Contamination was found to extend northward only as far as the Old Erie Canal, which parallels the base of the bluff. Only limited off-site involvement was documented which will be monitored in the post-closure period using the installed well system

  5. Aeolian sedimentation in the middle buntsandstein in the eifel north-south depression zone: Summary of the variability of sedimentary processes in a buntsandstein erg as a base for evaluation of the mutual relationships between aeolian sand seas and fluvial river systems in the mid-european buntsandstein

    Science.gov (United States)

    Mader, Detlef

    The spectrum of aeolian depositional subenvironments in the upper Middle Buntsandstein Karlstal-Schichten sequence in the Eifel North-South-zone at the western margin of the Mid-European Triassic Basin comprises trains of larger and higher narrowly-spaced dunes in sand seas, isolated smaller and lower widely-spaced dunes in floodplains and interdune playas, dry interdune sheet sands, damp interdune adhesive sandflats, wet interdune playa lakes, rainfall runoff watercourses and ephemeral channels cutting through the dune belt, and deflation gravel lag veneers. Distinction of aeolian and fluvial sediments within the succession of closely intertonguing wind- and water-laid deposits is possible by independent analysis of the conventional criteria and the more modern stratification styles. Thick cross-bedded aeolian sand sequences originate as barchanoid-type dunes which accumulate and migrate in the regime of narrow to wide unimodal southeasterly to southwesterly trade winds in low northern palaeolatitude in summer when the intertropical convergence zone is shifted to the north. The predominantly transverse-ridge dunes accrete mainly by grainfall and subcritical climbing of wind ripples, subordinately also by grainflow interfingering with grainfall. Horizontal-laminated aeolian sands form as sand sheets in dry interdune playas by subcritical migration of wind ripple trains, rarely also by plane bed accretion. Thin cross-bedded dune sands or horizontal-laminated aeolian sands capping fluvial cyclothems originate by deflation of emerged alluvial bar sands during low-water stages and subsequent accumulation of the winnowed sand as widely-spaced dunelets or chains of wind ripples in desiccated parts of the adjoining floodplain. The aeolian sand layers at the base of lacustrine cyclothems record migration of isolated little dunes across the dry playa floor at the beginning of a wetting-upwards cyclothem, with the sand deriving from deflation of fluvial incursions or

  6. Potatoes and Trout: Maintaining Robust Agriculture and a Healthy Trout Fishery in the Central Sands of Wisconsin

    Science.gov (United States)

    Fienen, M. N.; Bradbury, K. R.; Kniffin, M.; Barlow, P. M.; Krause, J.; Westenbroek, S.; Leaf, A.

    2015-12-01

    The well-drained sandy soil in the Wisconsin Central Sands is ideal for growing potatoes, corn, and other vegetables. A shallow sand and gravel aquifer provides abundant water for agricultural irrigation but also supplies critical base flow to cold-water trout streams. These needs compete with one another, and stakeholders from various perspectives are collaborating to seek solutions. Stakeholders were engaged in providing and verifying data to guide construction of a groundwater flow model which was used with linear and sequential linear programming to evaluate optimal tradeoffs between agricultural pumping and ecologically based minimum base flow values. The connection between individual irrigation wells as well as industrial and municipal supply and streamflow depletion can be evaluated using the model. Rather than addressing 1000s of wells individually, a variety of well management groups were established through k-means clustering. These groups are based on location, potential impact, water-use categories, depletion potential, and other factors. Through optimization, pumping rates were reduced to attain mandated minimum base flows. This formalization enables exploration of possible solutions for the stakeholders, and provides a tool which is transparent and forms a basis for discussion and negotiation.

  7. Undrained Cyclic Behaviour of Dense Frederikshavn Sand

    DEFF Research Database (Denmark)

    Nielsen, Søren Kjær; Ibsen, Lars Bo; Sørensen, Kris Wessel

    2013-01-01

    A modified contour diagram is created for the Frederikshavn Sand in the undrained case for a relative density of ID = 80 %. It can be used to estimate the number of cycles to failure for a given combination of pore pressure, average and cyclic load ratio. The diagram is based on a series of undra...

  8. Radiation safety in Australia's mineral sands industry

    International Nuclear Information System (INIS)

    Hughes, W.

    1989-06-01

    This brochure is part of a training package aiming to explain in simple terms what radiation is, how it affects people's lives and how, in the specific case of the mineral sand industry, the risk of ill-effects from low-level radioactivity could be effectively guarded against by simple and easily followed safety precautions. ills

  9. Geomechanical properties of lime stabilized clayey sands

    International Nuclear Information System (INIS)

    Arabani, M.; Karami, M. Veis

    2007-01-01

    Clayey sands that have low plasticity, low compressibility and high strength under loads, are suitable as a base material for any engineering construction projects as well as for roads and building construction. Decrease of plasticity and compressibility as well as increase in strength of these materials can be obtained by many different methods. Of these methods, lime stabilization is a common, applicable, and easy to use approach that can improve geomechanical and geotechnical properties of clayey sand fills. In this study some important geomechanical properties and geotechnical properties of clayey sands including compressive strength, CBR and elastic plastic behavior are investigated. A range of gradations representative of those gradations found in situ in the north of Iran were selected for testing and samples were artificially rebuilt in the laboratory. The mixes were then stabilized with hydrated lime and cured. Different mechanical tests were performed on mature materials. The stress-strain behavior of lime-stabilized mixes was plotted and a parabolic function was used to estimate the trend of stress-strain behavior. The data show that there is a correlation among the results of uniaxial load test, tensile strength, and CBR of the tested specimens. Also, results of the unconfined compression test and the indirect tensile strength test show that an increase in clay content up to a certain percent, in the clay-sand fills, tends to increase the strength of the materials in compression as well as in tension. (author)

  10. Market opportunities and challenges for oil sands

    International Nuclear Information System (INIS)

    Wise, T.H.

    2004-01-01

    The use of Alberta bitumen as a clean fuel depends on upgrading, transportation, and refining processes. Forecasts show that oil sands production, which includes synthetic crude oil (SCO), will surpass declining conventional production from the Western Canada Sedimentary Basin. The challenges facing the oils sands processing industry include: crude oil prices which affect the producer's market; market expansion options; diluent availability/cost; supply cost competitiveness; and, regional processing. The common market issues include light/heavy crude prices, oil sands crude qualities, prices of oil sands crudes, pipeline infrastructure, and competitive supplies. The issues facing the refiners are: refining margins, security of crude supply, refined product quality, and competitive product supply. It was noted that Alberta must retain or increase its share of the Midwest market. The market expansion options were reviewed for both downstream (refining) and upstream (upgrading) operations. New pipeline capacity is needed to reach more distant markets such as Southern Midwest, Washington, and California. The market is nearly saturated for Canada's heavy oil supply. More upgrading will be required as bitumen production increases. Market growth is still possible for Canada's SCO but according to forecasts, the market could also become saturated. To increase demand and allow supplies to grow, SCO prices may fall below light crude prices. It was noted that a balance must be achieved in order for producers to increase production and for refiner/upgraders to expand their conversion capacity. 13 figs

  11. Growing markets to sustain oil sands development

    International Nuclear Information System (INIS)

    Wise, T.H.

    2003-01-01

    The utilization of Alberta bitumen for the clean fuels market depends on upgrading, transportation, and refining processes. Forecasts show that oil sands production, which includes synthetic crude oil (SCO), will surpass declining conventional production in Western Canada. Several issues pose a challenge to the oil sands processing industry. The producers' market is affected by crude oil prices, market expansion options, diluent availability/cost, supply cost competitiveness, and regional processing. The common market issues include light/heavy crude prices, oil sands crude qualities, prices of oil sands crudes, pipeline infrastructure, and competitive supplies. The issues facing the refiners are: refining margins, security of crude supply, refined product quality, and competitive product supply. A brief review of markets for Canadian crude oil, including synthetic crude, was provided. The share of the Midwest market by Alberta must be retained and increased. The market expansion options were reviewed for both downstream (refining) and upstream (upgrading) operations. To reach more distant markets such as Southern Midwest, Washington, and California, new pipeline capacity would be required. The market is nearly saturated for Canada's heavy oil supply. More upgrading will be required as bitumen production increases. Market growth is still possible for Canada's SCO but according to forecasts, the market could also become saturated. To increase demand and allow supplies to grow, SCO prices may fall below light crude prices. It was noted that a balance must be achieved in order for producers to increase production and for refiner/upgraders to expand their conversion capacity. tabs., figs

  12. Microbial Characterization of Qatari Barchan Sand Dunes.

    Directory of Open Access Journals (Sweden)

    Sara Abdul Majid

    Full Text Available This study represents the first characterization of sand microbiota in migrating barchan sand dunes. Bacterial communities were studied through direct counts and cultivation, as well as 16S rRNA gene and metagenomic sequence analysis to gain an understanding of microbial abundance, diversity, and potential metabolic capabilities. Direct on-grain cell counts gave an average of 5.3 ± 0.4 x 105 cells g-1 of sand. Cultured isolates (N = 64 selected for 16S rRNA gene sequencing belonged to the phyla Actinobacteria (58%, Firmicutes (27% and Proteobacteria (15%. Deep-sequencing of 16S rRNA gene amplicons from 18 dunes demonstrated a high relative abundance of Proteobacteria, particularly enteric bacteria, and a dune-specific-pattern of bacterial community composition that correlated with dune size. Shotgun metagenome sequences of two representative dunes were analyzed and found to have similar relative bacterial abundance, though the relative abundances of eukaryotic, viral and enterobacterial sequences were greater in sand from the dune closer to a camel-pen. Functional analysis revealed patterns similar to those observed in desert soils; however, the increased relative abundance of genes encoding sporulation and dormancy are consistent with the dune microbiome being well-adapted to the exceptionally hyper-arid Qatari desert.

  13. Afyon-Sandıklı

    Indian Academy of Sciences (India)

    δ18O and δD isotope ratios of the Sandıklı waters plot along the continental meteoric water line ... and district heating. Several studies on geology, hydrogeology along ..... precipitation; In: Handbook of Environmental Isotope. Geochemistry ...

  14. Engineered channel controls limiting spawning habitat rehabilitation success on regulated gravel-bed rivers

    Science.gov (United States)

    Brown, Rocko A.; Pasternack, Gregory B.

    2008-05-01

    In efforts to rehabilitate regulated rivers for ecological benefits, the flow regime has been one of the primary focal points of management strategies. However, channel engineering can impact channel geometry such that hydraulic and geomorphic responses to flow reregulation do not yield the sought for benefits. To illustrate and assess the impacts of structural channel controls and flow reregulation on channel processes and fish habitat quality in multiple life stages, a highly detailed digital elevation model was collected and analyzed for a river reach right below a dam using a suite of hydrologic, hydraulic, geomorphic, and ecological methods. Results showed that, despite flow reregulation to produce a scaled-down natural hydrograph, anthropogenic boundary controls have severely altered geomorphic processes associated with geomorphic self-sustainability and instream habitat availability in the case study. Given the similarity of this stream to many others, we concluded that the potential utility of natural flow regime reinstatement in regulated gravel-bed rivers is conditional on concomitant channel rehabilitation.

  15. Measuring gravel transport and dispersion in a mountain river using passive radio tracers

    Science.gov (United States)

    Bradley, D. N.; Tucker, G. E.

    2012-01-01

    Random walk models of fluvial sediment transport recognize that grains move intermittently, with short duration steps separated by rests that are comparatively long. These models are built upon the probability distributions of the step length and the resting time. Motivated by these models, tracer experiments have attempted to measure directly the steps and rests of sediment grains in natural streams. This paper describes results from a large tracer experiment designed to test stochastic transport models. We used passive integrated transponder (PIT) tags to label 893 coarse gravel clasts and placed them in Halfmoon Creek, a small alpine stream near Leadville, Colorado, USA. The PIT tags allow us to locate and identify tracers without picking them up or digging them out of the streambed. They also enable us to find a very high percentage of our rocks, 98% after three years and 96% after the fourth year. We use the annual tracer displacement to test two stochastic transport models, the Einstein–Hubbell–Sayre (EHS) model and the Yang–Sayre gamma-exponential model (GEM). We find that the GEM is a better fit to the observations, particularly for slower moving tracers and suggest that the strength of the GEM is that the gamma distribution of step lengths approximates a compound Poisson distribution. Published in 2012. This article is a US Government work and is in the public domain in the USA.

  16. The provenance of Taklamakan desert sand

    Science.gov (United States)

    Rittner, Martin; Vermeesch, Pieter; Carter, Andrew; Bird, Anna; Stevens, Thomas; Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Dutt, Ripul; Xu, Zhiwei; Lu, Huayu

    2016-03-01

    Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U-Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run

  17. Soil erosion rates caused by wind and saltating sand stresses in a wind tunnel

    International Nuclear Information System (INIS)

    Ligotke, M.W.

    1993-02-01

    Wind erosion tests were performed in a wind tunnel in support of the development of long-term protective barriers to cap stabilized waste sites at the Hanford Site. Controlled wind and saltating sand erosive stresses were applied to physical models of barrier surface layers to simulate worst-case eolian erosive stresses. The goal of these tests was to provide information useful to the design and evaluation of the surface layer composition of an arid-region waste site barrier concept that incorporates a deep fine-soil reservoir. A surface layer composition is needed that will form an armor resistant to eolian erosion during periods of extreme dry climatic conditions, especially when such conditions result in the elimination or reduction of vegetation by water deprivation or wildfire. Because of the life span required of Hanford waste barriers, it is important that additional work follow these wind tunnel studies. A modeling effort is planned to aid the interpretation of test results with respect to the suitability of pea gravel to protect the finite-soil reservoir during long periods of climatic stress. It is additionally recommended that wind tunnel tests be continued and field data be obtained at prototype or actual barrier sites. Results wig contribute to barrier design efforts and provide confidence in the design of long-term waste site caps for and regions

  18. The coal deposits of the Alkali Butte, the Big Sand Draw, and the Beaver Creek fields, Fremont County, Wyoming

    Science.gov (United States)

    Thompson, Raymond M.; White, Vincent L.

    1952-01-01

    Large coal reserves are present in three areas located between 12 and 20 miles southeast of Riverton, Fremont County, central Wyoming. Coal in two of these areas, the Alkali Butte coal field and the Big Sand Draw coal field, is exposed on the surface and has been developed to some extent by underground mining. The Beaver Creek coal field is known only from drill cuttings and cores from wells drilled for oil and gas in the Beaver Creek oil and gas field.These three coal areas can be reached most readily from Riverton, Wyo. State Route 320 crosses Wind River about 1 mile south of Riverton. A few hundred yards south of the river a graveled road branches off the highway and extends south across the Popo Agie River toward Sand Draw oil and gas field. About 8 miles south of the highway along the Sand Draw road, a dirt road bears east and along this road it is about 12 miles to the Bell coal mine in the Alkali Butte coal field. Three miles southeast of the Alkali Butte turn-off, 3 miles of oiled road extends southwest into the Beaver Creek oil and gas field. About 6 miles southeast of the Beaver Creek turn-off, in the valley of Little Sand Draw Creek, a dirt road extends east 1. mile and then southeast 1 mile to the Downey mine in the Big Sand Draw coal field. Location of these coal fields is shown on figure 1 with their relationship to the Wind River basin and other coal fields, place localities, and wells mentioned in this report. The coal in the Alkali Butte coal field is exposed partly on the Wind River Indian Reservation in Tps. 1 and 2 S., R. 6 E., and partly on public land. Coal in the Beaver Creek and Big Sand Draw coal fields is mainly on public land. The region has a semiarid climate with rainfall averaging less than 10 in. per year. When rain does fall the sandy-bottomed stream channels fill rapidly and are frequently impassable for a few hours. Beaver Creek, Big Sand Draw, Little Sand Draw, and Kirby Draw and their smaller tributaries drain the area and flow

  19. High temperature thermal energy storage in moving sand

    Science.gov (United States)

    Turner, R. H.; Awaya, H. I.

    1978-01-01

    Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

  20. Characteristics of SCC with Fly Ash and Manufactured Sand

    Science.gov (United States)

    Praveen Kumar, K.; Radhakrishna

    2016-09-01

    Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

  1. Field test on sand compaction pile method with copper slag sand; Dosuisai slag wo mochiita SCP koho no shiken seko

    Energy Technology Data Exchange (ETDEWEB)

    Minami, K.; Matsui, H.; Naruse, E.; Kitazume, M. [Port and Harbour Research Inst., Kanagawa (Japan)

    1997-09-20

    This paper describes the sand compaction pile (SCP) method using copper slag sand. The SCP method is a method by which sand compaction piles are constructed in the ground, and improvement can be obtained in a short period. This method has been widely used even in the port areas for enhancing the bearing power of soft clay ground and the lateral resistance of sheet pile. A great deal of sand is required as a material. The sand requires high permeability, proper size distribution with less fine particle fraction content, easy compaction property with enough strength, and easy discharging property from the casing of construction machines as required properties. Recently, it becomes hard to secure proper sand materials. The copper slag sand is obtained from refining process of copper as a by-product which is quenched in water flow and crushed in water. The copper slag sand has higher particle density than that of sand, excellent permeability, and similar size distribution to that of sand. From compaction drainage triaxial compression test and permeability test, it was found that the mechanical properties of copper slag sand did not change by the crushing of grains with keeping excellent permeability. Through the test construction, applicability of the copper slag sand to the SCP method could be confirmed as an alternate material of sand. 17 refs., 9 figs., 4 tabs.

  2. The effects of flooding disturbance on the distribution and behaviour of riparian arthropods along a lowland gravel river

    OpenAIRE

    Lambeets, Kevin

    2009-01-01

    This Ph.D.-thesis aimed to address which environmental factors influence the assemblage structure of mobile, riparian arthropods along spatially structured river banks of a rain-fed, lowland gravel river, the Common Meuse. As riverine ecosystems are basically non-equilibrium, dynamic ecosystems, mainly flow regimes and flood pulse characteristics are expected to shape both the distribution and behaviour of its inhabitants. The river banks along the Common Meuse are (in)frequently disturbed by...

  3. A New Method for Tracking Individual Particles During Bed Load Transport in a Gravel-Bed River

    Science.gov (United States)

    Tremblay, M.; Marquis, G. A.; Roy, A. G.; Chaire de Recherche Du Canada En Dynamique Fluviale

    2010-12-01

    Many particle tracers (passive or active) have been developed to study gravel movement in rivers. It remains difficult, however, to document resting and moving periods and to know how particles travel from one deposition site to another. Our new tracking method uses the Hobo Pendant G acceleration Data Logger to quantitatively describe the motion of individual particles from the initiation of movement, through the displacement and to the rest, in a natural gravel river. The Hobo measures the acceleration in three dimensions at a chosen temporal frequency. The Hobo was inserted into 11 artificial rocks. The rocks were seeded in Ruisseau Béard, a small gravel-bed river in the Yamaska drainage basin (Québec) where the hydraulics, particle sizes and bed characteristics are well known. The signals recorded during eight floods (Summer and Fall 2008-2009) allowed us to develop an algorithm which classifies the periods of rest and motion. We can differentiate two types of motion: sliding and rolling. The particles can also vibrate while remaining in the same position. The examination of the movement and vibration periods with respect to the hydraulic conditions (discharge, shear stress, stream power) showed that vibration occurred mostly before the rise of hydrograph and allowed us to establish movement threshold and response times. In all cases, particle movements occurred during floods but not always in direct response to increased bed shear stress and stream power. This method offers great potential to track individual particles and to establish a spatiotemporal sequence of the intermittent transport of the particle during a flood and to test theories concerning the resting periods of particles on a gravel bed.

  4. Efficiency of phenol biodegradation by planktonic Pseudomonas pseudoalcaligenes (a constructed wetland isolate) vs. root and gravel biofilm.

    Science.gov (United States)

    Kurzbaum, Eyal; Kirzhner, Felix; Sela, Shlomo; Zimmels, Yoram; Armon, Robert

    2010-09-01

    In the last two decades, constructed wetland systems gained increasing interest in wastewater treatment and as such have been intensively studied around the world. While most of the studies showed excellent removal of various pollutants, the exact contribution, in kinetic terms, of its particular components (such as: root, gravel and water) combined with bacteria is almost nonexistent. In the present study, a phenol degrader bacterium identified as Pseudomonas pseudoalcaligenes was isolated from a constructed wetland, and used in an experimental set-up containing: plants and gravel. Phenol removal rate by planktonic and biofilm bacteria (on sterile Zea mays roots and gravel surfaces) was studied. Specific phenol removal rates revealed significant advantage of planktonic cells (1.04 × 10(-9) mg phenol/CFU/h) compared to root and gravel biofilms: 4.59 × 10(-11)-2.04 × 10(-10) and 8.04 × 10(-11)-4.39 × 10(-10) (mg phenol/CFU/h), respectively. In batch cultures, phenol biodegradation kinetic parameters were determined by biomass growth rates and phenol removal as a function of time. Based on Haldane equation, kinetic constants such as μ(max) = 1.15/h, K(s) = 35.4 mg/L and K(i) = 198.6 mg/L fit well phenol removal by P. pseudoalcaligenes. Although P. pseudoalcaligenes planktonic cells showed the highest phenol removal rate, in constructed wetland systems and especially in those with sub-surface flow, it is expected that surface associated microorganisms (biofilms) will provide a much higher contribution in phenol and other organics removal, due to greater bacterial biomass. Factors affecting the performance of planktonic vs. biofilm bacteria in sub-surface flow constructed wetlands are further discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Southeast Florida Sediment Assessment and Needs Determination (SAND) Study

    Science.gov (United States)

    2014-09-01

    sand with some shell beds, sandstone , and limestone *Miami Limestone 0 to 80 ft Oolitic limestone, quartz sand, and sandstone Anastasia 0 to 100 ft...Sand, shell beds, marl, calcareous sandstone (coquina/calcarenite) Fort Thompson 0 to 80 ft Silty limestone, silty sand, clayey marl, shell marl...highly- to moderately- weathered quartzose sandstone , and highly-weathered (saprolitic) to moderately-weathered hard limestone. North-south and

  6. Biodegradable materials as binders for IVth generation moulding sands

    OpenAIRE

    K. Major-Gabry

    2015-01-01

    This paper focuses on the possibility of using the biodegradable materials as binders (or parts of binders?compositions) for foundry moulding and core sands. Results showed that there is a great possibility of using available biodegradable materials as foundry moulding sand binders. Using biodegradable materials as partial content of new binders, or additives to moulding sands may not only decrease the toxicity and increase reclamation ability of tested moulding sands, but also accelerate the...

  7. SPECIFIC RESISTANCE AND SPECIFIC INTENSITY OF BELT SANDING OF WOOD

    Directory of Open Access Journals (Sweden)

    Boleslaw Porankiewicz

    2010-06-01

    Full Text Available This paper examines and discusses the specific belt sanding resistance K (N·cm-2 and specific belt sanding intensity SI (g·cm-2·min-1, for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v.

  8. Quality stabilisation of synthetic sand containing bentonite in process lines

    OpenAIRE

    A. Fedoryszyn

    2010-01-01

    Stabilisation of sand quality requires the monitoring and control of sand moisture contents and its other parameters at each stage of sandprocessing, i.e. during the preparation of return sand mix and rebonding processes. Stabilisation of sand quality necessitates the use of reliable control equipment and evaluation procedures. This study outlines the scope and results of research work aimed to improve the control equipment to enhance the performance of turbine mixers. The paper reviews the m...

  9. Evaluate of head loss, sediment value and copper removal in sand media (rapid sand filter

    Directory of Open Access Journals (Sweden)

    Daneshi Navab

    2014-06-01

    Full Text Available Along with the technology development and increasing consumption of water resources, we are experiencing low qualities in the mentioned resources. Copper brings about serious environment al pollution, threatening human health and ecosystem. This metal found variously in water resources and industrial activities. Therefore, it needs to treat the water resources from these excessive amounts. Different methods have used for this reason but the most used method during recent years has been the absorption by economic absorbers such as sand. Rapid sand filters usually used in water and wastewater treatment plants for water clarification. In this research, a single layer gravity rapid sand filter has used to reduce different concentrations of copper. sediment value and head loss arising in filter media is simulated by using combination of Carman-Kozeny, Rose and Gregory models in different discharges of rapid sand filter. Results have shown that with increasing in discharge and decreasing in input copper concentration, arriving time to given head loss, is increasing. In addition, results demonstrated that with increasing in copper concentration in influent, removal efficiency is decreasing somewhat. Results of this research can applied in an appropriate design of rapid sand filter to copper removal, a prediction of rapid sand filter ability to copper removal and an estimation of arising head loss during filter work thus evaluating of time interval backwash. DOI: http://dx.doi.org/10.3126/ije.v3i2.10641 International Journal of the Environment Vol.3(2 2014: 276-286

  10. Influence of limestone waste as partial replacement material for sand and marble powder in concrete properties

    Directory of Open Access Journals (Sweden)

    Omar M. Omar

    2012-12-01

    Full Text Available Green concrete are generally composed of recycling materials as hundred or partial percent substitutes for aggregate, cement, and admixture in concrete. Limestone waste is obtained as a by-product during the production of aggregates through the crushing process of rocks in rubble crusher units. Using quarry waste as a substitute of sand in construction materials would resolve the environmental problems caused by the large-scale depletion of the natural sources of river and mining sands. This paper reports the experimental study undertaken to investigate the influence of partial replacement of sand with limestone waste (LSW, with marble powder (M.P as an additive on the concrete properties. The replacement proportion of sand with limestone waste, 25%, 50%, and 75% were practiced in the concrete mixes except in the concrete mix. Besides, proportions of 5%, 10% and 15% marble powder were practiced in the concrete mixes. The effects of limestone waste as fine aggregate on several fresh and hardened properties of the concretes were investigated. The investigation included testing of compressive strength, indirect tensile strength, flexural strength, modulus of elasticity, and permeability. It was found that limestone waste as fine aggregate enhanced the slump test of the fresh concretes. But the unit weight concretes were not affected. However, the good performance was observed when limestone waste as fine aggregate was used in presence of marble powder.

  11. The Grain-size Patchiness of Braided Gravel-Bed Streams - example of the Urumqi River (northeast Tian Shan, China)

    Science.gov (United States)

    Guerit, L.; Barrier, L.; Narteau, C.; Métivier, F.; Liu, Y.; Lajeunesse, E.; Gayer, E.; Meunier, P.; Malverti, L.; Ye, B.

    2014-02-01

    In gravel-bed rivers, sediments are often sorted into patches of different grain-sizes, but in braided streams, the link between this sorting and the channel morpho-sedimentary elements is still unclear. In this study, the size of the bed sediment in the shallow braided gravel-bed Urumqi River is characterized by surface-count and volumetric sampling methods. Three morpho-sedimentary elements are identified in the active threads of the river: chutes at flow constrictions, which pass downstream to anabranches and bars at flow expansions. The surface and surface-layer grain-size distributions of these three elements show that they correspond to only two kinds of grain-size patches: (1) coarse-grained chutes, coarser than the bulk river bed, and (2) finer-grained anabranches and bars, consistent with the bulk river bed. In cross-section, the chute patches are composed of one coarse-grained top layer, which can be interpreted as a local armour layer overlying finer deposits. In contrast, the grain size of the bar-anabranch patches is finer and much more homogeneous in depth than the chute patches. Those patches, which are features of lateral and vertical sorting associated to the transport dynamics that build braided patterns, may be typical of active threads in shallow gravel-bed rivers and should be considered in future works on sorting processes and their geomorphologic and stratigraphic results.

  12. A study of the influence of a gravel subslab layer on radon entry rate using two basement structures

    International Nuclear Information System (INIS)

    Robinson, A.L.; Sextro, R.G.; Fisk, W.J.; Garbesi, K.; Wooley, J.; Wollenberg, H.A.

    1993-01-01

    In buildings with elevated radon concentrations, the dominant transport mechanism of radon is advective flow of soil gas into the building substructure. However, the building-soil system is often complex, making detailed studies of the radon source term difficult. In order to examine radon entry into buildings, the authors have constructed two room-size, precisely-fabricated basement structures at a site with relatively homogeneous, moderately permeable soil. The basements are identical except that one lies directly on native soil whereas the other lies on a high permeability aggregate layer. The soil pressure field and radon entry rate have been measured for different basement pressures and environmental conditions. The subslab gravel layer greatly enhances the advective entry of radon into the structure; when the structures are depressurized, the radon entry rate into the structure with the subslab gravel layer is more than a factor of 3 times the radon entry rate into the other structure for the same depressurization. The gravel subslab layer also spreads the pressure field around the structure, extending the field of influence of the structure and the region from which it draws radon

  13. The relative contribution of near-bed vs. intragravel horizontal transport to fine sediment accumulation processes in river gravel beds

    Science.gov (United States)

    Casas-Mulet, Roser; Lakhanpal, Garima; Stewardson, Michael J.

    2018-02-01

    Understanding flow-sediment interactions is important for comprehending river functioning. Fine sediment accumulation processes, in particular, have key implications for ecosystem health. However, the amount of fines generated by intragravel flows and later accumulated in gravel streambeds may have been underestimated, as the hydraulic-related driving transport mechanisms in play are not clearly identified. Specifically, the relative contribution of fines from upper vs. lower sediment layers in gravel beds is not well understood. By recreating flooded and dewatered conditions in an experimental flume filled with natural sediment, we estimated such contributions by observing and collecting intragravel transported fines that were later accumulated into a void in the middle of the sediment matrix. Near-bed transport in the upper sediment layers (named Brinkman load) during flooded conditions accounted for most (90%) of the accumulated fines. Intragravel transport in the lower sediment layers (named Interstitial load) was the sole source of transport and accumulation during dewatered conditions with steeper hydraulic gradients. Interstitial load accounted for 10% of the total transport during flooded conditions. Although small, such estimations demonstrate that hydraulic-gradient transport in the lower sediment layers occurs in spite of the contradicting analytical assessments. We provide a case study to challenge the traditional approaches of assessing intragravel transport, and a useful framework to understand the origin and relative contribution of fine sediment accumulation in gravel beds. Such knowledge will be highly useful for the design of monitoring programs aiding river management, particularly in regulated rivers.

  14. A study of the influence of a gravel subslab layer on radon entry rate using two basement structures

    International Nuclear Information System (INIS)

    Robinson, A.L.; Sextro, R.G.; Fisk, W.J.; Garbesi, K.; Wooley, J.; Wollenberg, H.A.

    1993-01-01

    In buildings with elevated radon concentrations, the dominant transport mechanism of radon is advective flow of soil gas into the building substructure. However, the building-soil system is often complex, making detailed studies of the radon source term difficult. In order-to examine radon entry into buildings, we have constructed two room-size, precisely-fabricated basement structures at a site with relatively homogeneous, moderately permeable soil. The basements are identical except that one lies directly on native soil whereas the other lies on a high permeability aggregate layer. The soil pressure field and radon entry rate have been measured for different basement pressures and environmental conditions. The subslab gravel layer greatly enhances the advective entry of radon into the structure; when the structures are depressurized, the radon entry rate into the structure with the subslab gravel layer is more than a factor of 3 times the radon entry rate into the other structure for the same depressurization. The gravel subslab layer also spreads the pressure field around the structure, extending the field of influence of the structure and the region from which it draws radon. (orig.). (7 refs., 3 figs.)

  15. Dewatering Behaviour of Fine Oil Sands Tailings : An Experimental Study

    NARCIS (Netherlands)

    Yao, Y.

    2016-01-01

    Oil sands tailings are a warm aqueous suspension of sand, silt, clay, residual bitumen and naphtha. The tailings are hydraulically transported and stored in tailing ponds where they segregate, with the sand settling from suspension forming beaches and the remaining tailings flowing to the middle of

  16. Design and Fabrication of a Foundry Sand Mixer Using Locally ...

    African Journals Online (AJOL)

    Most small foundry shops mix their sand manually which is not efficient since homogenous mix cannot be guaranteed and even when foundry mixer are available most of them are imported costing the nation huge foriegn exchange. A foundry sand mixer capable of mixing foundry sand has been designed and fabricated ...

  17. Seasonal changing sand waves and the effect of surface waves

    NARCIS (Netherlands)

    Sterlini, Fenneke; van Dijk, Thaiënne A.G.P.; IJzer, Steven; Hulscher, Suzanne; Schüttrumpf, Holger; Tomasicchio, Guiseppe Roberto

    2012-01-01

    Sand waves are wavelike subaqueous sediment structures that exist in large areas in shelf seas. Due to their characteristics sand waves can severely affect human offshore activities, such as navigation. This makes it important to understand the physical processes that shape and change sand waves. In

  18. Short Communications Sand moisture as a factor determining depth ...

    African Journals Online (AJOL)

    1993-11-05

    Nov 5, 1993 ... The depths to which the animals burrow are, at least partly. determined by the moisture gradient in the sand. They are, however, incapable of burrowing into totally dry sand. Animals alter their position in the sand in response to changes in moisture content so as to ensure exposure to suitable conditions.

  19. Assessing environmental impacts of inland sand mining in parts of ...

    African Journals Online (AJOL)

    Sand is a valuable resource for construction and other purposes, however sand mining often result in serious environmental problems such as land degradation, loss of agricultural lands and biodiversity, as well increased poverty among people. This study assessed the environmental impacts of inland sand mining in six ...

  20. Acetylcholinesterase mutations and organophosphate resistance in sand flies and mosquitoes

    Science.gov (United States)

    Leishmaniasis is an insect-borne disease caused by several protozoan species in the genus Leishmania, which are vectored by sand fly species in the genera Phlebotomus or Lutzomyia, depending on the sand fly species geographic range. Sand fly bites and leishmaniasis significantly impacted U.S. milita...

  1. The effective stress concept in saturated sand-clay buffer

    International Nuclear Information System (INIS)

    Graham, J.; Oswell, J.M.; Gray, M.N.

    1992-01-01

    Tests were performed on mixtures of sand and bentonite, to investigate whether the behavior of the mixture can be expressed in terms of effective stresses, defined as the tensor difference between externally applied total stresses and pore water pressures measured outside the cell. Within acceptable bounds of experimental error, the tests show that effective stress can be used to describe consolidation and shear behaviour. However, because part of the effective stress in the clay is derived from net interparticle repulsive (unit) forces seated in diffuse double layers around aggregations of bentonite particles, the applicability of the concept has at this stage been restricted to conditions of constant volume (or possibly constant straining rate), constant chemistry, and constant temperature

  2. Sand Needs and Resources Offshore New York

    Science.gov (United States)

    Lashley, J. M.; Flood, R. D.; White, M.; Bokuniewicz, H.; Hinrichs, C.; Wilson, R. E.

    2016-02-01

    "Superstorm" Sandy (October, 2012) accentuated the persistent problem of coastal erosion on New York's ocean coast. The New York state Department of State in cooperation with the Bureau of Ocean Energy Management has initiated further identification and assessment of marine sand reserves required to improve the resiliency of coastal communities and the maintenance of coastal habitats. The historical demand for beach nourishment has been about 1.5 million cubic meters per year, but sea level rise and the occurrence of extreme conditions may increase the demand to over 5 million cubic meters annually. Forty-four historical and proposed borrow sites have been delineated. This inner shelf is both sand rich and data rich. Geophysical and geological data has been compiled and reassessed to support identification, characterization, and delineation of sand resources for potential use in future coastal restoration, beach nourishment, and/or wetland restoration efforts. The South Shore of Long Island is composed in part by the Fire Island National Seashore. Holocene sand ridges extending at an oblique angle to the cross shore in the seaward direction. Borrow pits among the sand ridges, excavated were apparent in the most recent surveys and it appears that natural replenishment of offshore borrow areas has been occurring although the rates need to be determined in order to assess their sustainability. Not only is the area one of intense societal attention, but the use of this resource for coastal resilience must fit into a diverse framework marine spatial planning including not only traditional components, like commercial fishing, but also new factors like the siting of offshore wind-farms. To extend this assessment will include a recent survey, sponsored by the Bureau of Ocean Energy Management and the New York Department of State, providing approximately 700 km of geophysical survey lines located between 3 and 9 nautical miles offshore, and 46 geotechnical samples

  3. The Rheology of Acoustically Fluidized Sand

    Science.gov (United States)

    Conrad, J. W.; Melosh, J.

    2013-12-01

    The collapse of large craters and the formation of central peaks and peak rings is well modeled by numerical computer codes that incorporate the acoustic fluidization mechanism to temporarily allow the fluid-like flow of rock debris immediately after crater excavation. Furthermore, long runout landslides require a similar mechanism to explain their almost frictionless movement, which is probably also a consequence of their granular composition coupled with internal vibrations. Many different investigators have now confirmed the ability of vibrations to fluidize granular materials. Yet it still remains to fully describe the rheology of vibrated sand as a function of stress, frequency and amplitude of the vibrations in the sand itself. We constructed a rotational viscometer to quantitatively investigate the relation between the stress and strain rate in a horizontal bed of strongly vibrated sand. In addition to the macroscopic stain rate, the amplitude and frequency of the vibrations produced by a pair of pneumatic vibrators were also measured with the aid of miniaturized piezoelectric accelerometers (B&K 4393) whose output was recorded on a digital storage oscilloscope. The initial gathering of the experimental data was difficult due to granular memory, but by having the sand compacted vibrationally for 8 minutes before each run the scatter of data was reduced and we were able to obtain consistent results. Nevertheless, our major source of uncertainty was variations in strain rate from run to run. We find that vibrated sand flows like a highly non-Newtonian fluid, in which the shear strain rate is proportional to stress to a power much greater than one, where the precise power depends on the amplitude and frequency of the applied vibrations. Rapid flow occurs at stresses less than half of the static yield stress (that is, the yield stress when no vibration is applied) when strong vibrations are present. For a Newtonian fluid, such as water, the relation between

  4. Assessment of Large Wood budget in the gravel-bed Piave River: first attempt

    Science.gov (United States)

    Tonon, Alessia; Picco, Lorenzo; Ravazzolo, Diego; Aristide Lenzi, Mario

    2015-04-01

    During the last decades, the dynamics of large wood (LW) in rivers were analyzed to consider and define the LW budget. The space-time variations of LW amount results from the differences among input (e.g. fluvial transport, lateral recruitment) and output (e.g. fluvial transport, overbank deposition, natural chronic dead) of LW along a riverine environment. Different methodologies were applied in several fluvial environments, however in large river systems characterized by complex LW dynamics, the processes are still poor quantified. Aim of this contribution is to perform a LW budget estimation over the short period, assessing the effect of an over bankfull flood (Q=1039 m3 s-1; R.I=3.5 years). The research was carried out along a 1 km-long reach (around 15 ha) located into the middle course of the large gravel-bed Piave River (North East of Italy). The LW budget has been defined considering the recruitment through bank erosion and the fluvial transport of LW into and out of the study reach. The former factor was achieved integrating field data on riparian vegetation with the monitoring of riverbanks with a Differential Global Positioning System (DGPS). The latter was obtained detecting all LW elements (diameter ≥ 0.10 m and/or length ≥ 1 m) stored along the study reach, before and after the flood. For each LW the GPS position was recorded and a numbered tag was installed with the addition of colored paint to permit a rapid post-event recovery. Preliminary results indicate that, along the study area, the floating transport of LW is one of the most significant processes able to modify the amount of LW deposited along a riverine system. In fact, considering the input of LW, the 99.4 % (102 m3 km-1) comes from upstream due to floating, whereas the 0.6% (0.17 m3 km-1) was recruited through bank erosion. Analyzing the output, 94.3% (40.26 m3 km-1) of LW was transported downstream of the study area, whereas only the 5.7 % (2.43 m3 km-1) of LW was involved in the

  5. Geomorphic changes resulting from floods in reconfigured gravel-bed river channels in Colorado, USA

    Science.gov (United States)

    Elliott, J.G.; Capesius, J.P.

    2009-01-01

    Geomorphic changes in reconfi gured reaches of three Colorado rivers in response to floods in 2005 provide a benchmark for "restoration" assessment. Sedimententrainment potential is expressed as the ratio of the shear stress from the 2 yr, 5 yr, 10 yr, and 2005 floods to the critical shear stress for sediment. Some observed response was explained by the excess of flood shear stress relative to the resisting force of the sediment. Bed-load entrainment in the Uncompahgre River and the North Fork Gunnison River, during 4 and 6 yr floods respectively, resulted in streambed scour, streambed deposition, lateral-bar accretion, and channel migration at various locations. Some constructed boulder and log structures failed because of high rates of bank erosion or bed-material deposition. The Lake Fork showed little or no net change after the 2005 flood; however, this channel had not conveyed floods greater than the 2.5 yr flood since reconfi guration. Channel slope and the 2 yr flood, a surrogate for bankfull discharge, from all three reconfi gured reaches plotted above the Leopold and Wolman channel-pattern threshold in the "braided channel" region, indicating that braiding, rather than a single-thread meandering channel, and midchannel bar formation may be the natural tendency of these gravel-bed reaches. When plotted against a total stream-power and median-sediment-size threshold for the 2 yr flood, however, the Lake Fork plotted in the "single-thread channel" region, the North Fork Gunnison plotted in the " multiplethread" region, and the Uncompahgre River plotted on the threshold. All three rivers plotted in the multiple-thread region for floods of 5 yr recurrence or greater. ?? 2009 Geological Society of America.

  6. More than ten million years of hyper-aridity recorded in the Atacama Gravels

    Science.gov (United States)

    Sun, Tao; Bao, Huiming; Reich, Martin; Hemming, Sidney R.

    2018-04-01

    The Atacama Desert's hyper-aridity is closely linked to the development of world-class copper and nitrate/iodine ores and to regional tectonics and global paleoclimate changes in the Cenozoic era. The timing when the hyper-aridity commenced remains controversial, with proposed ages ranging from Late Oligocene to Pleistocene. In this study, we provide an independent constraint on the initiation of Atacama hyper-aridity utilizing a 100-m deep profile within the Atacama Gravels and underneath porphyry copper deposit in Spence, northern Chile. The overall high concentration of sulfate (up to 10 wt%) and a multimodal distribution of water soluble salt (sulfates, chlorides and nitrates) indicate multiple generations of sedimentation and salt accumulation events under semi-arid to hyper-arid climate conditions. The multiple sulfate isotope compositions (Δ17O, δ18O, δ34S) of the upper section (-15.0 to -34.5 m) are close to those of modern hyperarid surface sulfates, while the lower section (-34.5 to -65 m) displays a depth dependent isotope trend that is best interpreted as marking a period of climate change from semi-arid to hyper-arid. When these data are combined with new chronological 40Ar/39Ar dates obtained from a volcanic ash layer at depth of -28.0 m, our results show that hyper-arid condition in the Atacama Desert was prevailing at least prior to 9.47 Ma and may go back as old as the middle Miocene.

  7. Analytical study on the suitability of using bentonite coated gravel as a landfill liner material

    International Nuclear Information System (INIS)

    Roberts, Anel A.; Shimaoka, Takayuki

    2008-01-01

    This study investigates the feasibility of using bentonite coated gravel (BCG) as a liner material for waste landfills. BCG has proven to be a very effective capping material/method for the remediation of contaminated sediments in aquatic environments. The concept of BCG is similar to that of peanuts/almonds covered with chocolate; each aggregate particle has been covered with the clayey material. Laboratory tests were aimed at evaluating regulated and non-regulated factors for liner materials, i.e., permeability and strength. Tests included X-ray diffraction, methylene blue absorption, compaction, free swelling, permeability, 1D consolidation, triaxial compression and cone penetration. The compactive efforts used for this study were the reduced Proctor, standard Proctor, intermediate Proctor, modified Proctor and super modified Proctor. The compactive energy corresponding to each effort, respectively, is as follows: 355.5, 592.3, 1196.3, 2693.3, and 5386.4 kJ/m 3 . Results revealed that even though aggregate content represents 70% of the weight of the material, hydraulic conductivities as low as 6 x 10 -10 cm/s can be achieved when proper compactive efforts are used. Compressibility is very low for this material even at low (or no) compactive efforts. Results also demonstrated how higher compactive efforts can lower the permeability of BCG; however, over-compaction creates fractures in the aggregate core of BCG that could increase permeability. Moreover, higher compactive efforts create higher swelling pressures that could compromise the performance of a barrier constructed using BCG. As a result of this study, moderate compactive efforts, i.e., intermediate Proctor or modified Proctor, are recommended for constructing a BCG barrier. Using moderate compactive efforts, very low hydraulic conductivities, good workability and good trafficability are easily attainable

  8. The paratransgenic sand fly: a platform for control of Leishmania transmission.

    Science.gov (United States)

    Hurwitz, Ivy; Hillesland, Heidi; Fieck, Annabeth; Das, Pradeep; Durvasula, Ravi

    2011-05-19

    Leishmania donovani is transmitted by the bite of the sand fly, Phlebotomus argentipes. This parasite is the agent of visceral leishmaniasis (VL), an endemic disease in Bihar, India, where prevention has relied mainly on DDT spraying. Pesticide resistance in sand fly populations, environmental toxicity, and limited resources confound this approach. A novel paratransgenic strategy aimed at control of vectorial transmission of L. donovani is presented using Bacillus subtilis, a commensal bacterium isolated from the sand fly gut. In this work, B. subtilis expressing Green Fluorescent Protein (GFP) was added to sterilized larval chow. Control pots contained larval chow spiked either with untransformed B. subtilis or phosphate-buffered saline. Fourth-instar P. argentipes larvae were transferred into the media and allowed to mature. The number of bacterial colony forming units, relative abundance and the mean microbial load were determined per developmental stage. Addition of B. subtilis to larval chow did not affect sand fly emergence rates. B. cereus and Lys fusiformis were identified at each developmental stage, revealing transstadial passage of endogenous microbes. Larvae exposed to an exogenous bolus of B. subtilis harbored significantly larger numbers of bacteria. Bacterial load decreased to a range comparable to sand flies from control pots, suggesting an upper limit to the number of bacteria harbored. Emerging flies reared in larval chow containing transformed B. subtilis carried large numbers of these bacteria in their gut lumens. Strong GFP expression was detected in these paratransgenic flies with no spread of transformed bacteria to other compartments of the insects. This is the first demonstration of paratransgenic manipulation of P. argentipes. Paratransgenic manipulation of P. argentipes appears feasible. Expression of leishmanicidal molecules via commensal bacteria commonly found at breeding sites of P. argentipes could render adult sand flies refractory

  9. The physics of wind-blown sand and dust.

    Science.gov (United States)

    Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

    2012-10-01

    The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

  10. Longshore sediment transport at Golden Sands (Bulgaria

    Directory of Open Access Journals (Sweden)

    Hristo Nikolov

    2006-09-01

    Full Text Available The paper presents the results of studies on the qualitative and quantitative features of the littoral drift at Golden Sands (Bulgaria, carried out jointly by Polish and Bulgarian researchers. The mathematical modelling of physical coastal processes took wave transformation (wave diffraction and refraction; the effects of shoaling and wave breaking and longshore sediment transport into account. The computations were carried out for the mean statistical annual wave climate, determined on the basis of IO BAS wave data, simulated using the WAM method from long-term Black Sea wind data. The results of sediment transport computations clearly show that its direction off the Golden Sands shore is from north to south.

  11. Oil sands tailings preliminary ecological risk assessment

    International Nuclear Information System (INIS)

    1994-01-01

    Chemical data collected from various oil sands soil-tailings mixtures were used to determine the ecological risk that such tailings would pose to terrestrial wildlife at the surface of a reclaimed site. A methodology that could be used to evaluate the risks posed by various reclamation options (for dry land only) was proposed. Risks associated with other reclamation options, such as wet landscapes or deeper in-pit disposal, were not evaluated. Ten constituents (eight organic and two inorganic) were found to pose a threat to terrestrial biota. The relative contribution of different exposure pathways (water and food ingestion, incidental soil ingestion, inhalation) were studied by probabilistic models. Some physical and chemical reclamation alternatives which involve incorporating oil sands tailings in the landscape to produce a surface that could sustain a productive ecosystem, were described. 53 refs., 15 tabs., 3 figs

  12. Tailings dewatering in the oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Longo, S.; Labelle, M. [Golder Paste Technology, Sudbury, ON (Canada); Wislesky, I. [Golder Associates Ltd., Calgary, AB (Canada)

    2010-07-01

    Alberta's Directive 074 was established to reduce fluid tailings produced during oil sands extraction processes. This PowerPoint presentation examined some of the dewatering strategies available for oil sands operators and provided recommendations for implementing a dewatering plan. Sites must be evaluated in order to determine their chemistry, mineralogy, and the total quantity of material to be handled. The availability of potential additives must also be considered. Process technologies must be selected in relation to the operator's depositional strategy. Each site will require its own unique dewatering and depositional strategy. Dewatering technologies include thickening; in-line flocculation; centrifuge; co-mingling; and various new technologies such as electro-osmosis. Laboratory testing programs include index tests, primary stream thickening, and mini-pilot plant testing. The performance of various testing formats was evaluated. Thickening and depositional techniques were reviewed. tabs., figs.

  13. Radiation protection in the sand pit

    International Nuclear Information System (INIS)

    Hewson, Greg

    1997-01-01

    Radiation protection in the Western Australian minerals sands industry has attracted considerable controversy over the last 20 years: firstly, in relation to environmental and public health issues associated with the indiscriminate disposal of radioactive tailings as landfill in the mid to late 1970s and, secondly, in relation to occupational health issues associated with excessive radiation exposures to some workers at some plants in the mid to late 1980s. The industry also attracts attention through its proximity to coastal regions and population centres and consequent land use conflicts. Owing to intense political and societal scrutiny, and the emotional responses evoked by radiation, the industry's survival depends on a continuing high level of environmental and safety performance. This article summarises the successes and failures of the mineral sands industry in managing radiation protection and highlights some future issues and challenges for the industry. (Author)

  14. Oil sands market and transportation solutions

    International Nuclear Information System (INIS)

    Sandahl, R.

    2004-01-01

    This presentation outlined the immense potential of the western Canadian oil sands reserves. Recoverable reserves have been estimated at 180 billion barrels, with production forecasts estimated at 5 million barrels per day by 2030. Resource development is occurring at a time when the world's largest oil importer is increasing supplies through concern for security of supply. The second and third largest oil importers in the world are experiencing economic and energy demand growth. These factors underscore the motivation for rapid growth of the Western Canadian Oil Sands reserves. One of the challenges that must be addressed is to ensure that incremental markets for the increased production are accessed. Another challenge is to ensure adequate infrastructure in terms of pipeline capacity to ensure deliverability of the product. tabs., figs

  15. Pullout capacity of batter pile in sand.

    Science.gov (United States)

    Nazir, Ashraf; Nasr, Ahmed

    2013-03-01

    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21-31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18-75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  16. Fusion of arkosic sand by intrusive andesite

    Science.gov (United States)

    Bailey, Roy A.

    1954-01-01

    An andesite dike in the Valles Mountains of northern New Mexico has intruded and partly fused arkosic sediments for a distance of 50 feet from its contacts. The dike is semi-circular in form, has a maximum width of about 100 feet, and is about 500 feet long. Small associated arcuate dikes are arranged in spiral fashion around the main dike, suggesting that they were intruded along shear fractures similar to those described by Burbank (1941). The fused rocks surrounding the andesite dike are of three general types: 1) partly fused arkosic sand, 2) fused clay, and 3) hybrid rocks. The fused arkosic sand consists of relict detrital grains of quartz, orthoclose, and plagioclase, imbedded in colorless glass containing microlites of tridymite, cordierite, and magnetite. The relict quartz grains are corroded and embayed by glass; the orthoclase is sanidinized and partly fused; and the plagioclase is inverted to the high temperature form and is partly fused. The fused clay, which was originally a mixture of montmorillonite and hydromica, consists primarily of cordierite but also contains needle-like crystals of sillimanite (?) or mullite (?). The hybrid rocks originated in part by intermixing of fused arkosic sediments and andesitic liquid and in part by diffusion of mafic constituents through the fused sediments. They are rich in cordierite and magnetite and also contain hypersthene, augite, and plagioclase. The composition of pigeonite in the andesite indicates that the temperature of the andesite at the time of intrusion probably did not exceed 1200?C. Samples of arkosic sand were fused in the presence of water in a Morey bomb at 1050?C. Stability relations of certain minerals in the fused sand suggest that fusion may have taken place at a lower temperature, however, and the fluxing action of volatiles from the andesite are thought to have made this possible.

  17. Comparison of SAND-II and FERRET

    International Nuclear Information System (INIS)

    Wootan, D.W.; Schmittroth, F.

    1981-01-01

    A comparison was made of the advantages and disadvantages of two codes, SAND-II and FERRET, for determining the neutron flux spectrum and uncertainty from experimental dosimeter measurements as anticipated in the FFTF Reactor Characterization Program. This comparison involved an examination of the methodology and the operational performance of each code. The merits of each code were identified with respect to theoretical basis, directness of method, solution uniqueness, subjective influences, and sensitivity to various input parameters

  18. Drained Triaxial Tests on Eastern Scheldt Sand

    DEFF Research Database (Denmark)

    Praastrup, U.; Jakobsen, Kim Parsberg

    In the process of understanding and developing models for geomaterials, the stress-strain behaviour is commonly studied by performing triaxial tests. In the present study static triaxial tests have been performed to gain knowledge of the stress-strain behaviour of frictional materials during...... monotonic loading. The tests reported herein are all drained tests, starting from different initial states of stress and following various stress paths. AIl the tests are performed on reconstituted medium dense specimens of Eastern Scheldt Sand....

  19. Pullout capacity of batter pile in sand

    Directory of Open Access Journals (Sweden)

    Ashraf Nazir

    2013-03-01

    Full Text Available Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  20. Transport processes in intertidal sand flats

    Science.gov (United States)

    Wu, Christy

    2010-05-01

    Methane rich sulfate depleted seeps are observed along the low water line of the intertidal sand flat Janssand in the Wadden Sea. It is unclear where in the flat the methane is formed, and how it is transported to the edge of the sand flat where the sulfidic water seeps out. Methane and sulfate distributions in pore water were determined along transects from low water line toward the central area of the sand flat. The resulting profiles showed a zone of methane-rich and sulfate-depleted pore water below 2 m sediment depth. Methane production and sulfate reduction are monitored over time for surface sediments collected from the upper flat and seeping area. Both activities were at 22 C twice as high as at 15 C. The rates in sediments from the central area were higher than in sediments from the methane seeps. Methanogenesis occurred in the presence of sulfate, and was not significantly accelerated when sulfate was depleted. The observations show a rapid anaerobic degradation of organic matter in the Janssand. The methane rich pore water is obviously transported with a unidirectional flow from the central area of the intertidal sand flat toward the low water line. This pore water flow is driven by the pressure head caused by elevation of the pore water relative to the sea surface at low tide (Billerbeck et al. 2006a). The high methane concentration at the low water line accumulates due to a continuous outflow of pore water at the seepage site that prevents penetration of electron acceptors such as oxygen and sulfate to reoxidize the reduced products of anaerobic degradation (de Beer et al. 2006). It is, however, not clear why no methane accumulates or sulfate is depleted in the upper 2 m of the flats.

  1. Guide to preparing SAND reports. Revised

    Energy Technology Data Exchange (ETDEWEB)

    Locke, T.K. [ed.

    1996-04-01

    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, references, copyrights and permissions, and publishing terms.

  2. Analysis of wind-blown sand movement over transverse dunes.

    Science.gov (United States)

    Jiang, Hong; Huang, Ning; Zhu, Yuanjian

    2014-12-01

    Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification.

  3. Naphtha evaporation from oil sands tailings ponds

    Energy Technology Data Exchange (ETDEWEB)

    Kasperski, K.; Munoz, V.; Mikula, R. [Natural Resources Canada, Devon, AB (Canada). CANMET Western Research Centre

    2010-07-01

    The environmental impacts of volatile organic compounds (VOCs) from oil sands tailings ponds must be considered when evaluating new oil sands mining and extraction operations. Studies have suggested that only 40 percent of the solvent sent to tailings ponds is available to the environment, while the rest is irreversibly trapped. The recovery of hydrocarbons from oil sands froth process water is low. This PowerPoint presentation discussed a method of distinguishing between water and hydrocarbons at low temperatures. Samples were heated to 246 degrees C at 15 degrees C and held for 10 minutes. Heating was then resumed at 750 degrees C and held for 10 minutes in a pyrolysis phase, then cooled and reheated with an oxygen addition. The method demonstrated that the diluent distribution between the solids and water phases is misinterpreted as diluent that will evaporate, and diluent that will not evaporate. The study concluded by suggesting that the definition of recoverable and unrecoverable hydrocarbon should be re-termed as easily recoverable, and difficult to recover. tabs., figs.

  4. Insight conference reports : Western Canada oil sands

    International Nuclear Information System (INIS)

    2005-01-01

    This conference presented issues of concern to the Canadian oil sands industry. Focal points included supply and the potential for market growth as well as opportunities and challenges faced by the industry in the current market. Various projects were discussed, including the Northern Lights and Fort Hill projects. Reserves and resource booking procedures were examined, as well as issues concerning the streamlining of regulatory barriers and various approaches to the Kyoto Protocol and greenhouse gas (GHG) emissions. Oil sands portfolios were reviewed as well as issues concerning the recovery of titanium and zircon, the economics of Steam Assisted Gravity Drainage (SAGD) options and innovations in technology and sub-surface risk assessment for in-situ projects. Transportation initiatives were examined as well as pipeline issues and storage infrastructure development. Issues concerning financing as well as the economic environment of the oil sands industry were also discussed. The conference featured 20 presentations, of which 5 have been catalogued separately for inclusion in this database. tabs, figs

  5. Recycled sand in lime-based mortars.

    Science.gov (United States)

    Stefanidou, M; Anastasiou, E; Georgiadis Filikas, K

    2014-12-01

    The increasing awareness of the society about safe guarding heritage buildings and at the same time protecting the environment promotes strategies of combining principles of restoration with environmentally friendly materials and techniques. Along these lines, an experimental program was carried out in order to investigate the possibility of producing repair, lime-based mortars used in historic buildings incorporating secondary materials. The alternative material tested was recycled fine aggregates originating from mixed construction and demolition waste. Extensive tests on the raw materials have been performed and mortar mixtures were produced using different binding systems with natural, standard and recycled sand in order to compare their mechanical, physical and microstructure properties. The study reveals the improved behavior of lime mortars, even at early ages, due to the reaction of lime with the Al and Si constituents of the fine recycled sand. The role of the recycled sand was more beneficial in lime mortars rather than the lime-pozzolan or lime-pozzolan-cement mortars as a decrease in their performance was recorded in the latter cases due to the mortars' structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Numerical simulation of sand jet in water

    Energy Technology Data Exchange (ETDEWEB)

    Azimi, A.H.; Zhu, D.; Rajaratnam, N. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2008-07-01

    A numerical simulation of sand jet in water was presented. The study involved a two-phase flow using two-phase turbulent jets. A literature review was also presented, including an experiment on particle laden air jet using laser doppler velocimetry (LDV); experiments on the effect of particle size and concentration on solid-gas jets; an experimental study of solid-liquid jets using particle image velocimetry (PIV) technique where mean velocity and fluctuations were measured; and an experimental study on solid-liquid jets using the laser doppler anemometry (LDA) technique measuring both water axial and radial velocities. Other literature review results included a photographic study of sand jets in water; a comparison of many two-phase turbulent flow; and direct numerical simulation and large-eddy simulation to study the effect of particle in gas jet flow. The mathematical model and experimental setup were also included in the presentation along with simulation results for sand jets, concentration, and kinetic energy. The presentation concluded with some proposed future studies including numerical simulation of slurry jets in water and numerical simulation of slurry jets in MFT. tabs., figs.

  7. Mobil Oil Canada : Kearl Oil Sands Mine

    International Nuclear Information System (INIS)

    1997-01-01

    The upgrader design at Mobil's Kearl Oil Sands Mine were described. Included were feed characteristics, upgrader products, process schemes and their overall economics and upgrader technologies in use, including coking, deasphalting, hydrocracking, hydrotreating and visbreaking. Advantages and disadvantages of the upgrader technologies were highlighted. As far as the product is concerned, much of it is destined to U.S. refineries that are equipped to process the material. The Kearl Oil Sands Mine upgrading facility will likely use a combination of coker/hydrotreating, which is a well proven process for high value products that has been used in all five of Mobil's refineries in the U.S., and visbreaker/deasphalting, which has shown promise in bench-scale testing, but at present still has some potential commercial difficulties. Foremost among these are the high softening product of asphalt from visbroken products, questionable commercial feasibility of the low yield of pitch, and problems in the disposal of asphalt. Severe visbreaking also yields unstable products. Details of Mobil Canada's oil sands project were also summarized 2 tabs., 9 figs

  8. Experimental investigation of sanding propensity for the Andrew completion

    Energy Technology Data Exchange (ETDEWEB)

    Venkitaraman, A.; Li, H. [Schlumberger Perforating and Testing Center (United Kingdom); Leonard, A. J.; Bowden, P. R. [BP Exploration (United Kingdom)

    1998-12-31

    A series of laboratory experiments were performed on three reservoir core samples selected from two plot wells to confirm the likelihood of sand production during the completion phase of the planned Andrew horizontal wells, and to perform risk analysis of formation failure at the time of underbalance perforation, and expected producing conditions. CT scans revealed no perforation failure, and the core samples did not show any propensity to produce sand during single-phase oil flow. Transient sand production was observed when water cut was introduced, but sand production declined as the percentage of water cut was increased. There was no evidence of sand production in the core samples during depletion testing either, and the wells were subsequently completed with perforated cemented liners without sand control. No sand problems have been encountered in two years of production, with some wells in water cut and declined reservoir pressure of 200 psi. 8 refs., 3 tabs., 5 figs.

  9. Use of sand wave habitats by silver hake

    Science.gov (United States)

    Auster, P.J.; Lindholm, J.; Schaub, S.; Funnell, G.; Kaufman, L.S.; Valentine, P.C.

    2003-01-01

    Silver hake Merluccius bilinearis are common members of fish communities in sand wave habitats on Georges Bank and on Stellwagen Bank in the Gulf of Maine. Observations of fish size v. sand wave period showed that silver hake are not randomly distributed within sand wave landscapes. Regression analyses showed a significant positive relationship between sand wave period and fish length. Correlation coefficients, however, were low, suggesting other interactions with sand wave morphology, the range of current velocities, and available prey may also influence their distribution. Direct contact with sand wave habitats varied over diel periods, with more fish resting on the seafloor during daytime than at night. Social foraging, in the form of polarized groups of fish swimming in linear formations during crepuscular and daytime periods, was also observed. Sand wave habitats may provide shelter from current flows and mediate fish-prey interactions. ?? 2003 The Fisheries Society of the British Isles.

  10. bentonite-sand mixture as new backfill/buffer material

    International Nuclear Information System (INIS)

    Cui Suli; Liu Jisheng; Zhang Huyuan; Liang Jian

    2008-01-01

    The mixture of bentonite and quartz sand is suggested as a new backfill/buffer material for geological disposal of HLW. To improve the further design of underground laboratory and in-situ industrial construction test, the optimization of sand addition to bentonite is focused at present research stage. Based on summarizing the research results abroad, laboratory tests were conducted on the mixture of GMZ001 bentonite and quartz sand, such as compaction test and swelling tests etc. Test data shows that GMZ bentonite-sand mixture exhibits a favorite compaction with a 30% sand addition, a highest swelling pressure with a 20% sand addition, and a decreasing plasticity with increases in sand addition and pore liquid concentration. (authors)

  11. Properties of Shredded Roof Membrane–Sand Mixture and Its Application as Retaining Wall Backfill under Static and Earthquake Loads

    Directory of Open Access Journals (Sweden)

    Bennett Livingston

    2017-04-01

    Full Text Available About 20 billion square feet of Ethylene Propylene Diene Monomer (EPDM rubber is installed on roofs in the United States and most of them will be reaching the end of their lifespan soon. The purpose of this study is to investigate potential reuses of this rubber in Civil Engineering projects rather than disposing it into landfills. First, laboratory tests were performed on various shredded rubber-sand mixtures to quantify the basic geotechnical engineering properties. The laboratory test results show that the shredded rubber-sand mixture is lightweight with good drainage properties and has shear strength parameters comparable to sand. This indicates that the rubber-sand mixture has potential to be used for retaining wall backfill and many other projects. To assess the economic advantage of using shredded rubber-sand mixtures as a lightweight backfill for retaining walls subjected to static and earthquake loadings, geotechnical designs of a 6 m tall gravity cantilever retaining wall were performed. The computed volume of concrete to build the structural components and volume of backfill material were compared with those of conventional sand backfill. Results show significant reductions in the volume of concrete and backfill material in both static and earthquake loading conditions when the portion of shredded rubber increased in the mixture.

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

    Science.gov (United States)

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

    2002-01-01

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

  13. Achieving emissions reduction through oil sands cogeneration in Alberta’s deregulated electricity market

    International Nuclear Information System (INIS)

    Ouellette, A.; Rowe, A.; Sopinka, A.; Wild, P.

    2014-01-01

    The province of Alberta faces the challenge of balancing its commitment to reduce CO 2 emissions and the growth of its energy-intensive oil sands industry. Currently, these operations rely on the Alberta electricity system and on-site generation to satisfy their steam and electricity requirements. Most of the on-site generation units produce steam and electricity through the process of cogeneration. It is unclear to what extent new and existing operations will continue to develop cogeneration units or rely on electricity from the Alberta grid to meet their energy requirements in the near future. This study explores the potential for reductions in fuel usage and CO 2 emissions by increasing the penetration of oil sands cogeneration in the provincial generation mixture. EnergyPLAN is used to perform scenario analyses on Alberta’s electricity system in 2030 with a focus on transmission conditions to the oil sands region. The results show that up to 15–24% of CO 2 reductions prescribed by the 2008 Alberta Climate Strategy are possible. Furthermore, the policy implications of these scenarios within a deregulated market are discussed. - Highlights: • High levels of cogeneration in the oil sands significantly reduce the total fuel usage and CO 2 emissions for the province. • Beyond a certain threshold, the emissions reduction intensity per MW of cogeneration installed is reduced. • The cost difference between scenarios is not significant. • Policy which gives an advantage to a particular technology goes against the ideology of a deregulated market. • Alberta will need significant improvements to its transmission system in order for oil sands cogeneration to persist

  14. Ethoxyresorufin-O-deethylase (EROD) induction in rainbow trout exposed to diluted oil sand wastewater

    International Nuclear Information System (INIS)

    Verbeek, A.; Mackay, W.; Birkholz, D.

    1995-01-01

    Toxic industrial wastewaters, such as those from oil sands extraction, must be assessed for their potential sublethal effects before they can be safely disposed in the environment. The induction of ethoxyresorufin-O-deethylase activity was assessed as a potential bioindicator of sublethal stress in rainbow trout exposed to sublethal concentrations of oil sands tailings water. The mixed-function oxygenase system in rainbow trout responded rapidly following a definable concentration-response relationship; however, it proved to be a relatively insensitive indicator of sublethal exposure to oil sands tailings water. Increased activity and maximal induction, as a result of exposure to 0.3 and 0.6 times the LC 50 (Toxic Units), occurred rapidly within 24 hours of exposure. The linearity of the relationship between the concentration of oil sands tailings pond water and ethoxyresorufin-O-deethylase activity, expressed by the following regression equation, In EROD = 3.68 (conc.) + 3.20, had an r 2 value of 0.593. Maximal induction required 0.4--0.8 Toxic Units. The absolute level of maximal induction was only one-fifth to one-sixth of the potential induction as found in response to the positive control, 0.5 mg/kg β-naphthoflavone (i.p.). The authors also present data that suggests that the different levels of induction observed in trout exposed to tailings pond water vs those injected with 0.5 mg/kg β-naphthoflavone (i.p.) may be indicative of two different P450 isoforms, the CYP4Al isoform responding to the organic acidic surfactants in oil sands tailings pond water and the CYP1A1 isoform, the isoform generally associated with most xenobiotic transformation in fish, responding to β-naphthoflavone

  15. Critical bed shear stress and threshold of motion of maerl biogenic gravel

    Science.gov (United States)

    Joshi, Siddhi; Duffy, Garret Patrick; Brown, Colin

    2017-07-01

    A determination of the critical bed shear stress of maerl is a prerequisite for quantifying its mobility, rate of erosion and deposition in conservation management. The critical bed shear stress for incipient motion has been determined for the first time for samples from biogenic free-living maerl beds in three contrasting environments (open marine, intertidal and beach) in Galway Bay, west of Ireland. The bed shear stress was determined using two methods, Law of the Wall and Turbulent Kinetic Energy, in a rotating annular flume and in a linear flume. The velocity profile of flowing water above a bed of natural maerl grains was measured in four runs of progressively increasing flow velocity until the flow exceeded the critical shear stress of grains on the bed. The critical Shields parameter and the mobility number are estimated and compared with the equivalent curves for natural quartz sand. The critical Shields parameters for the maerl particles from all three environments fall below the Shields curve. Along with a previously reported correlation between maerl grain shape and settling velocity, these results suggest that the highly irregular shapes also allow maerl grains to be mobilised more easily than quartz grains with the same sieve diameter. The intertidal beds with the roughest particles exhibit the greatest critical shear stress because the particle thalli interlock and resist entrainment. In samples with a high percentage of maerl and low percentage of siliciclastic sand, the lower density, lower settling velocity and lower critical bed shear stress of maerl results in its preferential transport over the siliciclastic sediment. At velocities ∼10 cm s-1 higher than the threshold velocity of grain motion, rarely-documented subaqueous maerl dunes formed in the annular flume.

  16. Paleontological overview of oil shale and tar sands areas in Colorado, Utah, and Wyoming.

    Energy Technology Data Exchange (ETDEWEB)

    Murphey, P. C.; Daitch, D.; Environmental Science Division

    2009-02-11

    In August 2005, the U.S. Congress enacted the Energy Policy Act of 2005, Public Law 109-58. In Section 369 of this Act, also known as the ''Oil Shale, Tar Sands, and Other Strategic Unconventional Fuels Act of 2005,'' Congress declared that oil shale and tar sands (and other unconventional fuels) are strategically important domestic energy resources that should be developed to reduce the nation's growing dependence on oil from politically and economically unstable foreign sources. In addition, Congress declared that both research- and commercial-scale development of oil shale and tar sands should (1) be conducted in an environmentally sound manner using management practices that will minimize potential impacts, (2) occur with an emphasis on sustainability, and (3) benefit the United States while taking into account concerns of the affected states and communities. To support this declaration of policy, Congress directed the Secretary of the Interior to undertake a series of steps, several of which are directly related to the development of a commercial leasing program for oil shale and tar sands. One of these steps was the completion of a programmatic environmental impact statement (PEIS) to analyze the impacts of a commercial leasing program for oil shale and tar sands resources on public lands, with an emphasis on the most geologically prospective lands in Colorado, Utah, and Wyoming. For oil shale, the scope of the PEIS analysis includes public lands within the Green River, Washakie, Uinta, and Piceance Creek Basins. For tar sands, the scope includes Special Tar Sand Areas (STSAs) located in Utah. This paleontological resources overview report was prepared in support of the Oil Shale and Tar Sands Resource Management Plan Amendments to Address Land Use Allocations in Colorado, Utah, and Wyoming and PEIS, and it is intended to be used by Bureau of Land Management (BLM) regional paleontologists and field office staff to support future

  17. Evaluating the oil sands reclamation process: Assessing policy capacity and stakeholder access for government and non-governmental organizations operating in Alberta's oil sands

    Science.gov (United States)

    Patterson, Tyler

    By employing interpretive policy analysis this thesis aims to assess, measure, and explain policy capacity for government and non-government organizations involved in reclaiming Alberta's oil sands. Using this type of analysis to assess policy capacity is a novel approach for understanding reclamation policy; and therefore, this research will provide a unique contribution to the literature surrounding reclamation policy. The oil sands region in northeast Alberta, Canada is an area of interest for a few reasons; primarily because of the vast reserves of bitumen and the environmental cost associated with developing this resource. An increase in global oil demand has established incentive for industry to seek out and develop new reserves. Alberta's oil sands are one of the largest remaining reserves in the world, and there is significant interest in increasing production in this region. Furthermore, tensions in several oil exporting nations in the Middle East remain unresolved, and this has garnered additional support for a supply side solution to North American oil demands. This solution relies upon the development of reserves in both the United States and Canada. These compounding factors have contributed to the increased development in the oil sands of northeastern Alberta. Essentially, a rapid expansion of oil sands operations is ongoing, and is the source of significant disturbance across the region. This disturbance, and the promises of reclamation, is a source of contentious debates amongst stakeholders and continues to be highly visible in the media. If oil sands operations are to retain their social license to operate, it is critical that reclamation efforts be effective. One concern non-governmental organizations (NGOs) expressed criticizes the current monitoring and enforcement of regulatory programs in the oil sands. Alberta's NGOs have suggested the data made available to them originates from industrial sources, and is generally unchecked by government

  18. Mechanical Parameters of Rubber-Sand Mixtures for Numerical Analysis of a Road Embankment

    Science.gov (United States)

    Kowalska, Magdalena; Chmielewski, Maciej

    2017-10-01

    Waste production is one of the greatest problems of the modern world. It is inevitably related to the increase of industrialization. One of the most difficult, and growing in amounts, waste is scrap tyres. The most common method of utilization of end-of-life tyres by their incineration raises much concern in terms of air pollution. More sustainable seems to reuse the tyre derived products - rubber in particular - in civil engineering, where the interesting properties of this material may be effectively utilized. This paper presents results of direct shear strength tests on sand-rubber mixtures, which were next applied to a numerical FEM (finite element method) model of a road embankment built on soft ground. The laboratory tests, conducted for two types of scrap tyre rubber granulates (0.5 - 2 mm and 1 - 5 mm in size) mixed with medium fluvial sand in various proportions (5, 10, 30 and 50% by weight), proved that the unit weight of the mixtures is distinctly smaller that the unit weight of sand alone and at 50% rubber content it drops by half. The internal angle of friction stays almost unchanged for the mixtures with up to 10% of rubber (33 - 37°), but decreases by about 10° when the rubber content increases to 50%. In most of the cases analysed, the cohesion intercept is higher in case of sand-rubber mixtures when compared to sand alone. The numerical model simulated a 4.5 m high embankment with a 3 m thick layer made of sand-rubber mixtures, containing 0%, 10% or 30% of the waste product, founded on a weak subsoil (with a 3 m layer of organic soil). The results showed that stability factor of the structure built with the layer containing 30% of the coarser rubber granulate has increased from 1.60 - for sand only, to 2.15. The embankment was also able to carry load increased from 32 kPa to 45.5 kPa and its base showed much smaller settlement. The results prove that the use of tyre derived aggregates in embankment construction is not only an effective way of

  19. Parcperdue geopressure-geothermal project. Study a geopressured reservoir by drilling and producing a well in a limited geopressured water sand. Final technical report, September 28, 1979-December 31, 1983

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, J.R.; Stanley, J.G. (eds.)

    1984-01-15

    The behavior of geopressured reservoirs was investigated by drilling and producing a well in small, well defined, geopressured reservoir; and performing detailed pressure transient analysis together with geological, geophysical, chemical, and physical studies. The Dow-DOE L. R. Sweezy No. 1 well was drilled to a depth of 13,600 feet in Parcperdue field, just south of Lafayette, Louisiana, and began production in April, 1982. The production zone was a poorly consolidated sandstone which constantly produced sand into the well stream, causing damage to equipment and causing other problems. The amount of sand production was kept manageable by limiting the flow rate to below 10,000 barrels per day. Reservoir properties of size, thickness, depth, temperature, pressure, salinity, porosity, and permeability were close to predicted values. The reservoir brine was undersaturated with respect to gas, containing approximately 20 standard cubic feet of gas per barrel of brine. Shale dewatering either did not occur or was insignificant as a drive mechanism. Production terminated when the gravel-pack completion failed and the production well totally sanded in, February, 1983. Total production up to the sanding incident was 1.94 million barrels brine and 31.5 million standard cubic feet gas.

  20. Modeling wood dynamics, jam formation, and sediment storage in a gravel-bed stream

    Science.gov (United States)

    Eaton, B. C.; Hassan, M. A.; Davidson, S. L.

    2012-12-01

    In small and intermediate sized streams, the interaction between wood and bed material transport often determines the nature of the physical habitat, which in turn influences the health of the stream's ecosystem. We present a stochastic model that can be used to simulate the effects on physical habitat of forest fires, climate change, and other environmental disturbances that alter wood recruitment. The model predicts large wood (LW) loads in a stream as well as the volume of sediment stored by the wood; while it is parameterized to describe gravel bed streams similar to a well-studied field prototype, Fishtrap Creek, British Columbia, it can be calibrated to other systems as well. In the model, LW pieces are produced and modified over time as a result of random tree-fall, LW breakage, LW movement, and piece interaction to form LW jams. Each LW piece traps a portion of the annual bed material transport entering the reach and releases the stored sediment when the LW piece is entrained and moved. The equations governing sediment storage are based on a set of flume experiments also scaled to the field prototype. The model predicts wood loads ranging from 70 m3/ha to more than 300 m3/ha, with a mean value of 178 m3/ha: both the range and the mean value are consistent with field data from streams with similar riparian forest types and climate. The model also predicts an LW jam spacing that is consistent with field data. Furthermore, our modeling results demonstrate that the high spatial and temporal variability in sediment storage, sediment transport, and channel morphology associated with LW-dominated streams occurs only when LW pieces interact and form jams. Model runs that do not include jam formation are much less variable. These results suggest that river restoration efforts using engineered LW pieces that are fixed in place and not permitted to interact will be less successful at restoring the geomorphic processes responsible for producing diverse, productive

  1. Total Dissolved Gas Monitoring in Chum Salmon Spawning Gravels Below Bonneville Dam

    Energy Technology Data Exchange (ETDEWEB)

    Arntzen, Evan V.; Geist, David R.; Panther, Jennifer L.; Dawley, Earl

    2007-01-30

    At the request of the U.S. Army Corps of Engineers (Portland District), Pacific Northwest National Laboratory (PNNL) conducted research to determine whether total dissolved gas concentrations are elevated in chum salmon redds during spring spill operations at Bonneville Dam. The study involved monitoring the total dissolved gas levels at egg pocket depth and in the river at two chum salmon spawning locations downstream from Bonneville Dam. Dissolved atmospheric gas supersaturation generated by spill from Bonneville Dam may diminish survival of chum (Oncorhynchus keta) salmon when sac fry are still present in the gravel downstream from Bonneville Dam. However, no previous work has been conducted to determine whether total dissolved gas (TDG) levels are elevated during spring spill operations within incubation habitats. The guidance used by hydropower system managers to provide protection for pre-emergent chum salmon fry has been to limit TDG to 105% after allowing for depth compensation. A previous literature review completed in early 2006 shows that TDG levels as low as 103% have been documented to cause mortality in sac fry. Our study measured TDG in the incubation environment to evaluate whether these levels were exceeded during spring spill operations. Total dissolved gas levels were measured within chum salmon spawning areas near Ives Island and Multnomah Falls on the Columbia River. Water quality sensors screened at egg pocket depth and to the river were installed at both sites. At each location, we also measured dissolved oxygen, temperature, specific conductance, and water depth to assist with the interpretation of TDG results. Total dissolved gas was depth-compensated to determine when levels were high enough to potentially affect sac fry. This report provides detailed descriptions of the two study sites downstream of Bonneville Dam, as well as the equipment and procedures employed to monitor the TDG levels at the study sites. Results of the monitoring at

  2. Historical coseismic surface deformation of fluvial gravel deposits, Schafberg fault, Lower Rhine Graben, Germany

    Science.gov (United States)

    Kübler, Simon; Friedrich, Anke M.; Gold, Ryan D.; Strecker, Manfred R.

    2018-03-01

    Intraplate earthquakes pose a significant seismic hazard in densely populated rift systems like the Lower Rhine Graben in Central Europe. While the locations of most faults in this region are well known, constraints on their seismogenic potential and earthquake recurrence are limited. In particular, the Holocene deformation history of active faults remains enigmatic. In an exposure excavated across the Schafberg fault in the southwestern Lower Rhine Graben, south of Untermaubach, in the epicentral region of the 1756 Düren earthquake ( M L 6.2), we mapped a complex deformation zone in Holocene fluvial sediments. We document evidence for at least one paleoearthquake that resulted in vertical surface displacement of 1.2 ± 0.2 m. The most recent earthquake is constrained to have occurred after 815 AD, and we have modeled three possible earthquake scenarios constraining the timing of the latest event. Coseismic deformation is characterized by vertical offset of sedimentary contacts distributed over a 10-m-wide central damage zone. Faults were identified where they fracture and offset pebbles in the vertically displaced gravel layers and fracture orientation is consistent with the orientation of the Schafberg fault. This study provides the first constraint on the most recent surface-rupturing earthquake on the Schafberg fault. We cannot rule out that this fault acted as the source of the 1756 Düren earthquake. Our study emphasizes the importance of, and the need for, paleoseismic studies in this and other intracontinental regions, in particular on faults with subtle geomorphic expression that would not typically be recognized as being potentially seismically active. Our study documents textural features in unconsolidated sediment that formed in response to coseismic rupturing of the underlying bedrock fault. We suggest that these features, e.g., abundant oriented transgranular fractures in their context, should be added to the list of criteria used to identify a fault

  3. Harding - a field case study: Sand control strategy for ultra-high productivity and injectivity wells

    Energy Technology Data Exchange (ETDEWEB)

    McKay, G.; Bennett, C.; Price-Smith, C.; Dowell, S.; McLellan, W. [British Petroleum (United Kingdom)

    1998-12-31

    The strategy adopted and the factors considered in the development of the sandface completion design for Phase One of the Harding Field in the unconsolidated Balder Massive Sand in the U.K. Sector of the North Sea is described. The field development utilizes a TPG 500 Jack-up Drilling and Production Unit in conjunction with a concrete gravity base tank (GBT). The first phase of the development involved drilling and completing horizontal wells sand-free, ultra-high production (over 30,000 BOPD/well, with PI in excess of 1,000 bbl/day/psi). The experiences showed that pre-packed screens can be successfully utilized to provide lasting sand control with high rate of production in clean homogenous sandstones, and that testing for fluid compatibility, formation damage, screen plugging, corrosion and erosion potential are essential pre-requisites in determining the optimal solution in any well with sand production potential.The experiences gained in Phase One have contributed to design enhancements for Phase Two of the project which include extended reach horizontal wells to neighbouring satellite pools. 3 refs., 1 tab., 8 figs.

  4. Submerged Pond Sand Filter—A Novel Approach to Rural Water Supply

    Directory of Open Access Journals (Sweden)

    Mia Øhlenschlæger

    2016-06-01

    Full Text Available This study describes the new design and function of a modified version of a traditional slow sand filter. The Submerged Pond Sand Filter is built inside a pond and has a vertical as well as a horizontal flow of water through a sloped filter opening. The filter provides treated drinking water to a rural Indian village. The filter has functioned with minimal maintenance for five years without being subject to the typical scraping off and changing of sand as needed in traditional slow sand filters every few months. This five-year study showed bacterial removal efficiency of 97% on average with a level of faecal coliforms of 2 ± 2 colony forming units (CFU/100 mL measured in the treated water. Turbidity was visibly removed during treatment. When water was retrieved from the filter through a manual pump for long consistent time intervals (60 min, faecal coliform counts increased from four to 10 CFU/100 mL on average compared to shorter pumping intervals (5 min. Though the treated water did not comply with the World Health Organization standards of 0 CFU/100 mL, the filter significantly improved water quality and provided one of the best sources of drinkable water in a water-depleted area, where only surface water was available. Furthermore, it is a sustainable treatment method due to low maintenance requirements.

  5. BioTiger{sup TM} : a natural microbial product for enhanced hydrocarbon recovery from oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.L.; Berry, C.J.; Milliken, C.E.; Jones, W. [Savannah River National Laboratory, Aiken, SC (United States)

    2008-07-01

    This presentation discussed the feasibility of using BioTiger{sup TM} technology to increase hydrocarbon recovery from oil sands. This enhanced ex situ oil recovery processes was initially developed and used by the United States Department of Energy for bioremediation of soils contaminated with oil, but it may also be used to optimize bitumen separation. BioTiger was described as being a unique microbial consortia that has resulted from nearly a decade of extensive microbiology screening and characterization of samples collected from an old waste lagoon. The technology offers rapid and complete degradation of aliphatic and aromatic hydrocarbons and produces new surfactants. It is tolerant of both chemical and metal toxicity and has good activity at high temperatures at extreme pH levels. A flotation test protocol with oil sands from Fort McMurray, Alberta was used for the BioTiger evaluation. A comparison of hot water extraction/flotation test of the oil sands performed with BioTiger showed a 50 per cent improvement in separation as measured by gravimetric analysis. BioTiger is well suited for enhanced hydrocarbon recovery from oil sands because it performs well at high temperatures. 8 figs.

  6. Properties of dune sand concrete containing coffee waste

    Directory of Open Access Journals (Sweden)

    Mohamed Guendouz

    2018-01-01

    Full Text Available In the last years, an increase of coffee beverages consumption has been observed all over the world; and its consumption increases the waste coffee grounds which will become an environmental problems. Recycling of this waste to produce new materials like sand concrete appears as one of the best solutions for reduces the problem of pollution. This work aims to study the possibility of recycling waste coffee grounds (Spent Coffee Grounds (SCG as a fine aggregate by replacing the sand in the manufacturing of dune sand concrete. For this; sand concrete mixes were prepared with substitution of sand with the spent coffee grounds waste at different percentage (0%, 5%, 10%, 15% and 20% by volume of the sand in order to study the influence of this wastes on physical (Workability, bulk density and porosity, mechanical (compressive and flexural strength and Thermal (Thermal conductivity and thermal diffusivity properties of dune sand concrete. The results showed that the use of spent coffee grounds waste as partial replacement of natural sand contributes to reduce workability, bulk density and mechanical strength of sand concrete mixes with an increase on its porosity. However, the thermal characteristics are improved and especially for a level of 15% and 20% of substitution. So, it is possible to obtain an insulating material which can be used in the various types of structural components. This study ensures that reusing of waste coffee grounds in dune sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems.

  7. Policy Analysis of the Canadian Oil Sands Experience

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2013-09-01

    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 sands experience illustrates the risks that opponents of development believe should deter domestic policymakers from incenting U.S. oil sands development. This report does not seek to evaluate the particular underpinnings of either side of this policy argument, but rather attempts to delve into the question of whether the Canadian experience has relevance as a foundational model for U.S. oil sands development. More specifically, this report seeks to assess whether and how the Canadian oil sands experience might be predictive or instructive in the context of fashioning a framework for a U.S. oil sands industry. In evaluating the implications of these underpinnings for a prospective U.S. oil sands industry, this report concentrates on prospective development of the oil sands deposits found in Utah.

  8. Water and soil loss from landslide deposits as a function of gravel content in the Wenchuan earthquake area, China, revealed by artificial rainfall simulations.

    Science.gov (United States)

    Gan, Fengling; He, Binghui; Wang, Tao

    2018-01-01

    A large number of landslides were triggered by the Mw7.9 Wenchuan earthquake which occurred on 12th May 2008. Landslides impacted extensive areas along the Mingjiang River and its tributaries. In the landslide deposits, soil and gravel fragments generally co-exist and their proportions may influence the hydrological and erosion processes on the steep slopes of the deposit surface. Understanding the effects of the mixtures of soil and gravels in landslide deposits on erosion processes is relevant for ecological reconstruction and water and soil conservation in Wenchuan earthquake area. Based on field surveys, indoor artificial rainfall simulation experiments with three rainfall intensities (1.0, 1.5 and 2.0 mm·min-1) and three proportions of gravel (50%, 66.7% and 80%) were conducted to measure how the proportion of gravel affected soil erosion and sediment yield in landslide sediments and deposits. Where the proportion of gravel was 80%, no surface runoff was produced during the 90 minute experiment under all rainfall intensities. For the 66.7% proportion, no runoff was generated at the lowest rainfall intensity (1.0 mm·min-1). As a result of these interactions, the average sediment yield ranked as 50> 66.6> 80% with different proportions of gravel. In addition, there was a positive correlation between runoff generation and sediment yield, and the sediment yield lagging the runoff generation. Together, the results demonstrate an important role of gravel in moderating the mobilization of landslide sediment produced by large earthquakes, and could lay the foundation for erosion models which provide scientific guidance for the control of landslide sediment in the Wenchuan earthquake zone, China.

  9. Changes in active eolian sand at northern Coachella Valley, California

    Science.gov (United States)

    Katra, Itzhak; Scheidt, Stephen; Lancaster, Nicholas

    2009-04-01

    Climate variability and rapid urbanization have influenced the sand environments in the northern Coachella Valley throughout the late 20th century. This paper addresses changes in the spatial relationships among different sand deposits at northern Coachella Valley between two recent time periods by using satellite data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The approach employed here, involving multispectral thermal infrared (TIR) data and spectral mixture analysis, has shown that the major sand deposits can be spatially modeled at northern Coachella Valley. The "coarse-grained (quartz-rich) sand" deposit is associated with active eolian sand, and the "mixed sandy soil" and "fine-grained (quartz-rich) sand" deposits are associated with inactive eolian sand. The fractional abundance images showed a significant decrease between 2000 and 2006 in the percentage of active sand in the major depositional area for fluvial sediment, the Whitewater River, but also in two downwind areas: the Whitewater and Willow Hole Reserves. The pattern of the active sand appears to be related to variations in annual precipitation (wet and dry years) and river discharge in the northern Coachella Valley. We suggest here that recent human modifications to the major watercourses that supply sand affect the capability of fluvial deposition areas to restore sediments over time and consequently the responses of the sand transport system to climate change, becoming more sensitive to dry years where areas of active sand may shrink, degrade, and/or stabilize faster. The approach utilized in this study can be advantageous for future monitoring of sand in the northern Coachella Valley for management of these and similar environments.

  10. Effects of near-bed turbulence and micro-topography on macroinvertebrate movements across contrasting gravel-bed surfaces (Invited)

    Science.gov (United States)

    Buffin-Belanger, T. K.; Rice, S. P.; Reid, I.; Lancaster, J.

    2009-12-01

    Fluvial habitats can be described from a series of physical variables but to adequately address the habitat quality it becomes necessary to develop an understanding that combines the physical variables with the behaviour of the inhabitating organisms. The hypothesis of flow refugia provide a rational that can explain the persistence of macroinvertebrate communities in gravel-bed rivers when spates occur. The movement behaviour of macroinvertebrates is a key element to the flow refugia hypothesis, but little is known about how local near-bed turbulence and bed microtopography may affect macroinvertebrate movements. We reproduced natural gravel-bed substrates with contrasting gravel bed textures in a large flume where we were able to document the movement behaviour of the cased caddisfly Potamophylax latipennis for a specific discharge. The crawling paths and drift events of animals were analysed from video recordings. Characteristics of movements differ from one substrate to another. The crawling speed is higher for the small grain-size substrates but the mean travel distance remains approximately the same between substrates. For each substrate, the animals tended to follow consistent paths across the surface. The number of drift events and mean distance drifted is higher for the small grain-size substrate. ADV measurements close to the boundary allow detailed characterisation of near-bed hydraulic variables, including : skewness coefficients, TKE, UV correlation coefficients and integral time scales from autocorrelation analysis. For these variables, the vertical patterns of turbulence parameters are similar between the substrates but the amplitude of the average values and standard errors vary significantly. The spatial distribution of this variability is considered in relation to the crawling paths. It appears that the animals tend to crawl within areas of the substrate where low flow velocities and low turbulent kinetic energies are found, while sites that

  11. Using multiple bed load measurements: Toward the identification of bed dilation and contraction in gravel-bed rivers

    Science.gov (United States)

    Marquis, G. A.; Roy, A. G.

    2012-02-01

    This study examines bed load transport processes in a small gravel-bed river (Béard Creek, Québec) using three complementary methods: bed elevation changes between successive floods, bed activity surveys using tags inserted into the bed, and bed load transport rates from bed load traps. The analysis of 20 flood events capable of mobilizing bed material led to the identification of divergent results among the methods. In particular, bed elevation changes were not consistent with the bed activity surveys. In many cases, bed elevation changes were significant (1 to 2 times the D50) even if the bed surface had not been activated during the flood, leading to the identification of processes of bed dilation and contraction that occurred over 10% to 40% of the bed surface. These dynamics of the river bed prevent accurate derivation of bed load transport rates from topographic changes, especially for low magnitude floods. This paper discusses the mechanisms that could explain the dilation and contraction of particles within the bed and their implications in fluvial dynamics. Bed contraction seems to be the result of the winnowing of the fine sediments under very low gravel transport. Bed dilation seems to occur on patches of the bed at the threshold of motion where various processes such as fine sediment infiltration lead to the maintenance of a larger sediment framework volume. Both processes are also influenced by flood history and the initial local bed state and in turn may have a significant impact on sediment transport and morphological changes in gravel-bed rivers.

  12. A 2D hydrodynamic-sedimentological model for gravel-bed rivers. Part I: theory and validation

    OpenAIRE

    Gabriel Kaless; Mario A. Lenzi; Luca Mao

    2013-01-01

    This paper presents a novel 2D-depth average model especially developed for gravel-bed rivers, named Lican-Leufú (Lican=pebble and Leufu=river, in Mapuche’s language, the native inhabitants of Central Patagonia, Argentina). The model consists of three components: a hydrodynamic, a sedimentological, and a morphological model. The flow of water is described by the depth-averaged Reynolds equations for unsteady, free-surface, shallow water flows. It includes the standard k-e model for turbulence...

  13. Asian interests in Alberta oil sands

    International Nuclear Information System (INIS)

    Du Plessis, D.; Laureshen, C.

    2004-01-01

    The growing Asian interest in Alberta's oil sands and import opportunities was discussed along with the feasibility of marketing bitumen to Asia. Asia is an obvious new market for Canadian heavy oil and bitumen due to an increasing demand for petroleum products in Japan, Korea, Taiwan and China. This paper examined the following three criteria that will determine the success of any initiative to move Canadian crude oil to Asian-Pacific markets: (1) a sustainable supply from Alberta; a pipeline to transport the crude to a deepwater port on the west coast; and, a guaranteed market at the other end. The basis for Asian interest in Alberta's oil sands is the sustainable secure supply of oil for growing Asian markets; heavy dependence on supplies from the Middle East; the desire to diversify supply sources; and, opportunities to invest in oil sands developments. Examples of Asian (Japan, Korea, Taiwan and China) missions to Alberta were presented along with the challenges of getting products to market with reference to Enbridge's new market access plan, Terasen's staged capacity expansion for heavy crudes and refined products, and sea transport from Prince Rupert. The paper also included graphs depicting world GDP; incremental increase in world primary energy demand by fuel for 2000 to 2020; world oil demand by region; oil demand by region in Asia; oil demand and supply in northeast Asia (Japan, China, Korea) and dependence level on Middle Eastern oil; oil demand and supply in China; China's petroleum production and consumption; refined products market forecast for 2000 to 2020; 2002 crude oil imports to Asia; 2004 refining capacity; product quality comparisons; cost competitive study; and energy policy objectives for China, Japan, Korea and Taiwan. 19 figs

  14. Radiometric Characterization of Sand in Northeast Sinai

    International Nuclear Information System (INIS)

    Ramadan, Kh.A.; Badran, H.M.; Ramadan, Kh.A.; Seddeek, M.K.; Sharshar, T.

    2009-01-01

    Thirty-eight locations covering an area of 350 km 2 in northeast Sinai were investigated by gamma-ray spectroscopy using a 50% HPGe detector. The limits of area are Al-Arish North, El-Hasana South, El-Oga East, and El- Gifgafa West. The range of activity concentrations of 238 U, 234 Th, 226 Ra, 232 Th and 40 K are 0.6-35.2, 3.9-22.6, 4.7-29.6, 4.7-23.9, and 108-295 Bq/kg for sands, respectively. 137 Cs in the region ranged from 0.1-8.0 Bq/kg. No major difference between the studied area and that previously investigated in the costal area in North Sinai. Reliable correlations (R2 = 0.8-0.9) among 238 U, 234 Th, and 226 Ra isotopes was obtained. On the other hand, low correlation (R 2 = 0.6-0.7) was obtained from the analysis of the isotopes of 238 U-seies and 232 Th. No evidence of correlation between the concentrations of radioisotopes and pH contents, TOM, and grain size were found. The soil-plant transfer factor are 226 Ra and 232 Th, 40 K, and 137 Cs, respectively. The wild vegetations collected from the studied area have average concentrations of 1.9, 1.4, 1.3, 254, and 0.3 for 234 Th, 226 Ra, 232 Th, 40 K, and 137 Cs, respectively. The average concentrations of 226 Ra, 232 Th, and 40 K in water samples collected from five wells are 0.02, 0.02, and 1.1 Bq/l, respectively. The average absorbed dose rate for the sand samples were calculated to be 19.4 n Gy h-1. The Raeq activities of the sands are lower than the recommended maximum value of 370 Bq kg-1 criterion limit of Raeq activity for building materials

  15. Radiogenic heavy minerals in Brazilian beach sand

    International Nuclear Information System (INIS)

    Malanca, A.

    1998-01-01

    Sand samples collected on the beaches of the 'radioactive' Brazilian town of Guarapari were first separated by flotation in bromoform and successively divided into various magnetic fractions with a Franz isodynamic separator. concentrations of background radionuclides in samples of monazite, ilmenite, and zircon were determined by a γ-ray spectrometer. Chemical composition of monazite, ilmenite and magnetite were assessed by means of an electron microprobe. Monazite resulted to be relatively rich in ThO 2 whose abundance ranged from 5.3 to 7.7 (wt%). (author)

  16. Limitation of releases and filtration by sand

    International Nuclear Information System (INIS)

    Schektman, N.

    1986-01-01

    In the highly hypothetic case of a severe reactor accident, it may lead to an increase of pressure within the containment and up to a value above the calculated pressure. A procedure is necessary in this case to maintain the integrity of the containment to prevent a release of radioactive products to the environment, while controlling in the best way releases. So, EDF and the CEA have developed a device of decompression-filtration of the containment atmosphere, using a free penetration of the containment and a sand box; the device and its operation constitute the U5 procedure [fr

  17. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.

    2012-08-07

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  18. Prolífica George Sand

    Directory of Open Access Journals (Sweden)

    Àngels Santa

    2014-04-01

    Full Text Available A propósito de las obras de George Sand, Œuvres complètes. Sous la direction de Béatrice Didier. 1841-1842.Un hiver à Majorque. Édition critique par Angela Ryan. Horace.Édition critique par Jeanne Brunereau (París, Honoré Champion, 2013, 748 p. ISBN : 9782745319265 y Œuvres complètes. ́Sous la direction de Béatrice Didier. 1849.La petite Fadette. Édition critique par Andrée Mansau (París, Honoré Champion, 2013, 345p. ISBN : 9782745319203

  19. Investigation of Sand-Cement Grouts

    Science.gov (United States)

    1960-09-01

    I -IEN NO Isis Table 1 InvestiiatLon of Sand-Cement Crouts Data on Lhe Physical Properties of the inely Divided Mineral Admixt)res Blaine Specific...Itoi, tuicrlt.nel, Caiftrnia; fl1; aish, Illinois; ;1iaricito, California; Lo’ss, Yisniasi~pi; bentornitoe, Wy~caing. Physical drnta for the raateriais...increase i’: tne a.cunt of .anj th-?t coul be puiped. As the diatomite had a specific ,i’face about 1C tines that of the loe33, it would appear that this

  20. SandBlaster: Reversing the Apple Sandbox

    OpenAIRE

    Deaconescu, Răzvan; Deshotels, Luke; Bucicoiu, Mihai; Enck, William; Davi, Lucas; Sadeghi, Ahmad-Reza

    2016-01-01

    In order to limit the damage of malware on Mac OS X and iOS, Apple uses sandboxing, a kernel-level security layer that provides tight constraints for system calls. Particularly used for Apple iOS, sandboxing prevents apps from executing potentially dangerous actions, by defining rules in a sandbox profile. Investigating Apple's built-in sandbox profiles is difficult as they are compiled and stored in binary format. We present SandBlaster, a software bundle that is able to reverse/decompile Ap...