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1

Liquefaction Potential Assessment Of Silty And Silty-Sand Deposits: A Case Study  

NASA Astrophysics Data System (ADS)

The paper shows a case study concerning the liquefaction potential assessment of deposits which mainly consist of non plastic silts and sands (FC>35 %,Ip<10%, CF negligible). The site under study has been characterized by means of in situ tests (CPTU, SPT and DPSH), boreholes and laboratory tests on undisturbed and remolded samples. More specifically, classification tests, cyclic undrained stress-controlled triaxial tests and resonant column tests have been performed. Liquefaction susceptibility has been evaluated by means of several procedures prescribed by codes or available in technical literature. The evaluation of liquefaction potential has been carried out by means of three different procedure based on in situ and laboratory tests.

Lo Presti, Diego C. F.; Squeglia, Nunziante

2008-07-01

2

Behavior of nonplastic silty soils under cyclic loading.  

PubMed

The engineering behavior of nonplastic silts is more difficult to characterize than is the behavior of clay or sand. Especially, behavior of silty soils is important in view of the seismicity of several regions of alluvial deposits in the world, such as the United States, China, and Turkey. In several hazards substantial ground deformation, reduced bearing capacity, and liquefaction of silty soils have been attributed to excess pore pressure generation during dynamic loading. In this paper, an experimental study of the pore water pressure generation of silty soils was conducted by cyclic triaxial tests on samples of reconstituted soils by the slurry deposition method. In all tests silty samples which have different clay percentages were studied under different cyclic stress ratios. The results have showed that in soils having clay content equal to and less than 10%, the excess pore pressure ratio buildup was quicker with an increase in different cyclic stress ratios. When fine and clay content increases, excess pore water pressure decreases constant cyclic stress ratio in nonplastic silty soils. In addition, the applicability of the used criteria for the assessment of liquefaction susceptibility of fine grained soils is examined using laboratory test results. PMID:24672343

Ural, Nazile; Gunduz, Zeki

2014-01-01

3

Efficiency of Micro-fine Cement Grouting in Liquefiable Sand  

NASA Astrophysics Data System (ADS)

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

Mirjalili, Mojtaba; Mirdamadi, Alireza; Ahmadi, Alireza

2008-07-01

4

Variation in grain shape and surface textures of fine guartz sands in the South Texas Eolian Sand Sheet  

E-print Network

VARIATION IN GRAIN SHAPE AND SURFACE TEXTURES OF FINE QUARTZ SANDS IN THE SOUTH TEXAS EOLIAN SAND SHEET A Thesis by DONALD RALPH SIMS JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 198'4 Major Subject: Geology VARIATION IN GRAIN SHAPE AND SURFACE TEXTURES OF FINE QUARTZ SANDS IN THE SOUTH TEXAS EOLIAN SAND SHEET A Thesis by DONALD RALPH SINS JR. Approved as to style and content by: Jame...

Sims, Donald Ralph

2012-06-07

5

Effect of sediment concentration on artificial well recharge in a fine sand aquifer  

E-print Network

EFFECT OF SEDIMENT CONCENTRATION ON ARTIFICIAL WELL RECHARGE IN A FINE SAND AQUIFER A Thesis By MD. ATAUR RAHMAN Submitted to the Graduate College of the Texas ASM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1968 Major Subject: Agricultural Engineering EFFECT OF SEDIMENT CONCENTRATION ON ARTIFICIAL WELL RECHARGE IN A FINE SAND AqUIFER A Thesis By MD. ATAUR RAHMAN Approved as to style and content by: (Chairman of ommitt ) ( a o...

Rahman, Mohammed Ataur

2012-06-07

6

Filler effect of fine particle sand on the compressive strength of mortar  

NASA Astrophysics Data System (ADS)

The river sand, which is a non-pozzolanic material, was ground into 3 different particle sizes. Portland cement type I was replaced by the ground river sands at 10wt%-40wt% of binder to cast mortar. Compressive strengths of mortar were investigated and the filler effect of different fine particles of sand on the compressive strength of mortar was evaluated. The results show that the compressive strength of mortar contributed from the filler effect of smaller particles is higher than that of the coarser ones. The difference in compressive strength of mortar tends to be greater as the difference in ground river sand fineness increases. The results also suggest that ASTM C618 specification is not practically suitable for specifying pozzolan in concrete since the strength activity index of mortar containing ground river sand (high crystalline phase) with 33.8wt% of particles retained on a 45-?m sieve can pass the strength requirement.

Jaturapitakkul, Chai; Tangpagasit, Jatuphon; Songmue, Sawang; Kiattikomol, Kraiwood

2011-04-01

7

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

NASA Astrophysics Data System (ADS)

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

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

8

ISET Journal of Earthquake Technology, Paper No. 450, Vol. 41, No. 2-4, June-December 2004, pp. 249-260 CYCLIC AND MONOTONIC UNDRAINED SHEAR RESPONSE OF SILTY  

E-print Network

-260 CYCLIC AND MONOTONIC UNDRAINED SHEAR RESPONSE OF SILTY SAND FROM BHUJ REGION IN INDIA T.G. Sitharam, L in villages and cities. In many places of the affected area, large masses of silty sands were ejected;250 Cyclic and Monotonic Undrained Shear Response of Silty Sand from Bhuj Region in India Fig. 1 Location

Gupta, Vinay Kumar

9

Benthic indices and ecological quality of shallow Algeria fine sand community  

Microsoft Academic Search

This study applies six macrozoobenthos-based biotic indices in the shallow coastal waters along the Algerian coast (southern Mediterranean Sea) to establish a reference situation for future use. These shallow fine sand communities were sampled in seven bays along the Algerian coast during the 1980s and the beginning of the 1990s. For the first time, some of the benthic indices used

A. Bakalem; T. Ruellet; J. C. Dauvin

2009-01-01

10

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

SciTech Connect

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

Kennedy, S.K.

1985-01-01

11

Bauxite residue fines as an amendment to residue sands to enhance plant growth potential—a glasshouse study  

Microsoft Academic Search

Purpose  This glasshouse study was conducted to determine if amending bauxite residue sand with residue fines would improve its suitability\\u000a as a growth medium. Alcoa’s West Australian operations mechanically separate residue into two size fractions: residue fines\\u000a (which are dominated by particles 150 ?m). Residue sand represents the primary material used\\u000a as a growth medium for rehabilitation, and prior to amendments, it

Jonathan D. Anderson; Richard W. Bell; Ian R. Phillips

12

AGING EFFECT ON RELATIONSHIP BETWEEN LIQUEFACTION STRENGTH AND CONE RESISTANCE OF SAND CONTAINING NON-PLASTIC FINES  

NASA Astrophysics Data System (ADS)

In order to simulate aging effect on the relationship between penetration resistance qt and liquefaction strength RL in a short time, miniature cone penetration tests and subsequent cyclic triaxial tests are carried out in sand specimens containing fines added with a small amount of cement to make an accelerated test. In contrast to a unique cone resistance (qt) versus liquefaction strength (RL) relationship for specimens without cement despite large difference in relative density and fines content, higher fines content results in higher liquefaction strength for the same cone resistance for sand with cement, which is consistent with the trend found in the field investigation. Thus, it is revealed that the reason why higher fines content leads to higher liquefaction strength does not depend on fines content itself but aging (bonding) effect by fines, which tends to be pronounced as fines increase.

Ito, Fumiki; Kokusho, Takaji; Nagao, Yota

13

Methanogens and sulfate-reducing bacteria in oil sands fine tailings waste.  

PubMed

In the past decade, the large tailings pond (Mildred Lake Settling Basin) on the Syncrude Canada Ltd. lease near Fort McMurray, Alta., has gone methanogenic. Currently, about 60%-80% of the flux of gas across the surface of the tailings pond is methane. As well as adding to greenhouse gas emissions, the production of methane in the fine tailings zone of this and other settling basins may affect the performance of these settling basins and impact reclamation options. Enumeration studies found methanogens (10(5)-10(6) MPN/g) within the fine tailings zone of various oil sands waste settling basins. SRB were also present (10(4)-10(5) MPN/g) with elevated numbers when sulfate was available. The methanogenic population was robust, and sample storage up to 9 months at 4 degrees C did not cause the MPN values to change. Nor was the ability of the consortium to produce methane delayed or less efficient after storage. Under laboratory conditions, fine tailings samples released 0.10-0.25 mL CH4 (at STP)/mL fine tailings. The addition of sulfate inhibited methanogenesis by stimulating bacterial competition. PMID:11068680

Holowenko, F M; MacKinnon, M D; Fedorak, P M

2000-10-01

14

Pore water pressure increment model for saturated Nanjing fine sand subject to cyclic loading  

NASA Astrophysics Data System (ADS)

Three groups of dynamic triaxial tests were performed for saturated Nanjing fine sand subjected to uniform cyclic loading. The tested curves of the excess pore water pressure (EPWP) ratio variation with the ratio of the number of cycles are provided. The concept of the EPWP increment ratio is introduced and two new concepts of the effective dynamic shear stress ratio and the log decrement of effective stress are defined. It is found that the development of the EPWP increment ratio can be divided into three stages: descending, stable and ascending. Furthermore, at the stable and ascending stages, a satisfactory linear relationship is obtained between the accumulative EPWP increment ratio and natural logarithm of the effective dynamic shear stress ratio. Accordingly, the EPWP increment ratio at the number of cycles N has been deduced that is proportional to the log decrement of effective stress at the cycle number N-1, but is independent of the cyclic stress amplitude. Based on the analysis, a new EPWP increment model for saturated Nanjing fine sand is developed from tested data fitting, which provides a better prediction of the curves of EPWP generation, the number of cycles required for initial liquefaction and the liquefaction resistance.

Wang, Binghui; Chen, Guoxing; Jin, Dandan

2010-12-01

15

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

PubMed

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

Penner, Tara J; Foght, Julia M

2010-06-01

16

The fine sand Abra alba community of the bay of morlaix twenty years after the Amoco Cadiz oil spill  

Microsoft Academic Search

The fine sand Abra alba community from the Bay of Morlaix (western English Channel) was strongly affected by the Amoco Cadiz oil spill of April 1978. The long term changes in the community (1977–1996) show that reconstitution of this community is slow (over 10 yr). A progressive recolonization by amphipod Ampelisca populations constituting the dominant species is observed. The results

J-C Dauvin

1998-01-01

17

Sr-Nd isotopic and REE geochemical constraints on the provenance of fine-grained sands in the Ordos deserts, north-central China  

NASA Astrophysics Data System (ADS)

Surface sands and sandstones in the Ordos region, alluvial sands from the surrounding mountains, and fluvial sands in the Yellow River are systemically collected for granulometric, mineralogical, geochemical and isotopic analyses. Fine-grained fractions are small for the Ordos desert sands as well as alluvial sands of the surrounding mountains whereas they are abundant for fluvial sands of the Yellow River. Quartz, feldspar and muscovite are common minerals but their relative proportions are variable for various sediments. REE geochemical compositions are roughly identical but isotopic compositions, particularly ? Nd(0) values of fine-grained sands vary significantly in the Ordos deserts. Based on the integrated Sr-Nd isotopic data, the possible source areas are isotopically divided into four regions for fine-grained sands in the Ordos deserts: region A, the Helan-Yin mountain ranges; region B, the Ordos sandstone areas; region D, the Tarim Basin, the Alxa Plateau, the Hexi Corridor, the northern Qinghai-Xizang Plateau and the Yellow River drainage; and region E, the Jungger Basin and the southern Mongolia. Through geochemical and particularly isotopic comparisons in combination with expert meteorological and geographical knowledge, fine-grained sands in the Ordos deserts originated both from weathering of local sandstones and from blowing of fine sediments in region D. The input from region D is subordinate to the local source for fine-grained sands in the Ordos deserts. Contributions from weathering of local sandstones might be roughly homogeneous from the west to the east of the Ordos region as well as the input of fine-grained sediments from remote areas such as the Tarim Basin, the Qinghai-Xizang Plateau and the Alxa Plateau. Geographical Nd isotopic variations of fine-grained sands in the Ordos deserts might be caused by the input from adjacent places such as the Yellow River drainage due to the near-surface winds.

Rao, Wenbo; Chen, Jun; Tan, Hongbing; Jiang, Sanyuan; Su, Jiang

2011-09-01

18

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

PubMed

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

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

2013-01-01

19

Growth and reproduction assessment of fathead minnows inhabiting an oil-sands fine tailings pond  

SciTech Connect

The objective of this study was to assess the relative success of fathead minnows (Pimephales promelas) in Syncrude`s Large Scale Wet Option Fine Tailings Demonstration Pond (DP). The DP is a 4-ha pond, constructed in 1993, containing 69,000 m{sup 3} of fine tailings capped with 73,790 m{sup 3} of natural water. Endpoints associated with growth and reproduction, including total length, weight, body condition factor, number of eggs laid, and % hatch were monitored in DP and other ponds, in 1995 and 1996. Relative exposure to PAHs were estimated using the biochemical indicators 7-ethoxyresorufin-O-deethylase (EROD) and bile PAH metabolites. Data were collected through regular sampling, and the introduction and monitoring of breeding boards. The length frequency distribution of the minnows in DP was significantly different from other sites and age suggested that larval recruitment during the 1994 breeding season was low or absent. Spawning was delayed in DP. Liver EROD activity in the DP fish was slightly induced during the spring but not during the fall, indicating negligible exposure to EROD inducing compounds. Reproductive endpoints and bile PAH metabolite results will be discussed.

Siwik, P.; Paszkowski, C. [Univ. of Alberta, Edmonton, Alberta (Canada); Heuvel, M.R. van den; Dixon, D.G. [Univ. of Waterloo, Ontario (Canada); Boerger, H.; Meer, T. van; McKinnon, M. [Syncrude Canada Ltd., Fort McMurray, Alberta (Canada)

1995-12-31

20

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

NASA Astrophysics Data System (ADS)

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

Wyser, Emmanuel; Rudaz, Benjamin; Jaboyedoff, Michel

2014-05-01

21

REVISION OF RELATIVE DENSITY AND ESTIMATION OF LIQUEFACTION STRENGTH OF SANDY SOIL WITH FINE CONTENT  

NASA Astrophysics Data System (ADS)

It is generally known that liquefaction strength obtained from undrained cyclic triaxial test is influenced by various factors such as relative densities, fine content, grain size distributions and plasticity indexes. However, It is difficult to estimate liquefaction strength for various soil types from same physical properties. In order to estimate the liquefaction strength of various soil types such as silt, silty sands and clean sands, this study showed a method to revice relative density of sandy soil including more than 15% of fine content and the correlation between reviced relative density and void ratio ranges obtaind from maximum and minimum void ratio. Then, the relationships between void ratio ranges and liquefaction strengths from other studies was considered. As a result, the defference of liquefaction strength between reconstituted and undisturbed samples was recognized from the correlations revised relative density using void ratio ranges and fine content.

Nakazawa, Hiroshi; Haradah, Kenji

22

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

23

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

EPA Science Inventory

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

24

Induced liquefaction experiment in relatively dense, clay-rich sand deposits  

E-print Network

Induced liquefaction experiment in relatively dense, clay-rich sand deposits Yossef H. Hatzor,1 blast-induced liquefaction experiment at the field scale. The physical and mechanical properties, liquefaction may be induced in relatively dense silty and clayey sands (shear wave velocity >300 m sÃ?1

Gvirtzman, Haim

25

Sources and distribution of fine quartz sand in the northeastern Gulf of Mexico: a paleogeographic reconstruction using fourier grain shape analysis  

E-print Network

are diurnal with no appreciable semidiurnal component (Jones, 1973). The only permanent current capable of mov1ng sand- sized sediment observed on the shel f to date 1s the wave- induced longshore drift. Coastal studies 1ndicate that it is predominant1y... sediment is carried out of the study area. Most of the modern sediment which is supplied to the shel f by the Mississippi is mud- sized; the seaward limit of sand transport out from the river mouth is around our miles (Shepard, 1960). Hurr i canes have...

Bates, Charles Arthur

2012-06-07

26

Quantifying the role of sandy-silty sediments in generating slope failures during earthquakes: example from the Algerian margin  

NASA Astrophysics Data System (ADS)

The Algerian margin is a seismically active region, where during the last century, several large magnitude earthquakes took place. This study combines geotechnical and sedimentological data with numerical modelling to quantitatively assess the present-day slope stability of the Algerian margin. Geotechnical laboratory tests, such as cyclic triaxial tests, oedometric tests and vane shear tests were carried out on sediment cores collected on the study area. The liquefaction potential of a sediment column located about 30 km from the Boumerdès earthquake epicentre of 21st May 2003 was evaluated theoretically for an earthquake of M w = 6.8. We show that thin sand and silt beds such as those described on recovered sediment cores are the main cause of sediment deformation and liquefaction during earthquakes. Numerical calculations showed that the slope failure may occur during an earthquake characterised by a PGA in excess of 0.1 g, and also that, under a PGA of 0.2 g liquefaction could be triggered in shallow silty-sandy deposits. Moreover, comparison of the predicted slope failure with failure geometries inferred from seafloor morphology showed that earthquakes and subsequent mass movements could explain the present-day morphology of the study area.

Dan, Gabriela; Sultan, Nabil; Savoye, Bruno; Deverchere, Jacques; Yelles, Karim

2009-06-01

27

Materials based on highly concentrated ceramic binding suspensions (HCBS). Fabrication and properties of fine-grain foam concretes based on hcbs of quartz sand  

Microsoft Academic Search

Compositions and methods for fabricating highly porous siliceous (SiO2 > 90%) foam concretes based on HCBS of quartz sand and additives of liquid glass and slags of ferrochrome production are\\u000a described. Molding systems in the form of mineralized foams are self-solidifying and have a relatively low moisture content.\\u000a In the process of molding and drying the material does not practically

Yu. E. Pivinskii; T. N. Epifanova; N. A. Peretorkina

1998-01-01

28

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

Microsoft Academic Search

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

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

2006-01-01

29

Induced liquefaction experiment in relatively dense, clay-rich sand deposits  

NASA Astrophysics Data System (ADS)

In this paper we report results from a controlled blast-induced liquefaction experiment at the field scale. The physical and mechanical properties of the materials at the subsurface are characterized by a suite of in situ and laboratory tests, including the Standard Penetration Test (SPT); downhole and cross-hole seismic velocity tests; density, porosity, and gradation tests; and direct shear tests. Since the blast experiment was performed above groundwater table, the subsurface was saturated by a sequence of controlled infiltration tests. A 50-kg TNT charge was detonated at a depth of 10 m, and seismic ground motions were recorded in a vertical geophone array positioned at a horizontal distance of 30 m from the blast borehole. Obtained liquefaction features include a water fountain that erupted from the blast borehole, prolonged bubbling of the water surface inside the infiltration trench (a process equivalent to "sand boils" typically observed at sites which have experienced liquefaction), lateral spreading, and surface settlement. We argue that in contrast to conventional predictions, liquefaction may be induced in relatively dense silty and clayey sands (shear wave velocity >300 m s-1; relative density = 63-89%) relatively rich in clays (fines content >30%) and that the driving mechanism should not necessarily be restricted to cyclic shear stress loading.

Hatzor, Yossef H.; Gvirtzman, Haim; Wainshtein, Ilia; Orian, Itay

2009-02-01

30

Sand Stories  

NSDL National Science Digital Library

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

Christensen, Hilary

31

Effect of gassy sand lenses on a deep excavation in a clayey soil  

Microsoft Academic Search

Gas venting (mainly methane) was encountered during a deep excavation in a 40m thick clayey deposit (with silty sand lenses) overlying a shale layer believed to be the source of biogenic gas. The upward diffusion of methane and chloride from the bedrock aquifer through the clay till is modeled and the potential for chloride migration contributing to the exsolution of

Ahmed Mabrouk; R. Kerry Rowe

2011-01-01

32

Influence of Agricultural Land Use and Management on the Contents of Polycyclic Aromatic Hydrocarbons in Selected Silty Soils  

Microsoft Academic Search

The aim of the present study was the influence of various methods of long-term soil utilisation on the content of polycyclic\\u000a aromatic hydrocarbons (PAH) in selected silty soils. Four soils were selected for the present studies, i.e.: Eutric Fluvisol originating from silty formations, Haplic Phaeozem developed from loess, Haplic Luvisol (non-uniform) developed from silt, Haplic Luvisol developed from loess. Five

Patryk Oleszczuk; Jacek Pranagal

2007-01-01

33

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

34

Sand Dunes  

NSDL National Science Digital Library

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

Enright, Rachel

35

Elastic properties of unconsolidated porous sand reservoirs  

Microsoft Academic Search

The effect of compressive stress and pore fluid properties on elastic properties of unconsolidated sand reservoirs was determined by laboratory velocity and pore volume measurements on two specimens. These consisted of a naturally occurring very fine grained sand and glass beads, each with a porosity of approximately 38 percent. Compressional- and shear-wave velocities and pore compressibility were measured in the

S. N. Domenico

1977-01-01

36

Booming Sands  

NSDL National Science Digital Library

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

Foundation, Wgbh E.

2007-04-19

37

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

38

Liquefaction characteristics of a fine sand  

E-print Network

in test 4-7 underwent limited liquefaction in that it was in a liquefied state only from point 1 to point 2 before the sample was reconverted into a solid state. The sample in 4-8 was dilatant and it did not liquefy at all. On the basis of the behavior... illustrated in Fig. 1 (p. 7)& Youd (24) has proposed the following definitions for liquefaction and related deformation. Liquefaction is defined as the transformation of a granular material from a solid state into a liquefied state as a consequence...

Brandon, Donald Timothy

2012-06-07

39

Defrosting Sand  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

40

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

USGS Publications Warehouse

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

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

2007-01-01

41

Sands at Gusev Crater, Mars  

NASA Astrophysics Data System (ADS)

environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

Cabrol, Nathalie A.; Herkenhoff, Kenneth; Knoll, Andrew H.; Farmer, Jack; Arvidson, Raymond; Grin, Edmond; Li, Ronxing; Fenton, Lori; Cohen, Barbara; Bell, James F.; Aileen Yingst, R.

2014-05-01

42

Defrosting Sand  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

43

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

USGS Publications Warehouse

The Sparta Sand and Memphis Sand form the second most productive aquifer in Arkansas. The Sparta Sand and Memphis Sand range in thick- ness from 0 to 900 feet, consisting of fine- to medium-grained sands interbedded with layers of silt, clay, shale, and minor amounts of lignite. Within the three areas of interest, the top surface of the Sparta Sand and Memphis Sand dips regionally east and southeast towards the axis of the Mississippi Embayment syncline and Desha Basin. Local variations in the top surface may be attributed to a combination of continued development of structural features, differential compaction, localized faulting, and erosion of the surface prior to subsequent inundation and deposition of younger sediments.

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

1998-01-01

44

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin  

Microsoft Academic Search

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,20014C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of

Louis J. Maher; Norton G. Miller; Richard G. Baker; B. Brandon Curry; David M. Mickelson

1998-01-01

45

Stone heave field experiment in sand  

NASA Astrophysics Data System (ADS)

Movements of 24 cm large globes and cuboids of granite, concrete and wood were recorded during four and a half years. The objects were buried at three different depths in well-sorted sand in a natural cool temperate environment. All objects moved during the experiment and at the end most wood objects, which had a relatively low thermal conductivity had moved up, and the granite and concrete objects with higher thermal conductivities had sunk a little or remained almost in place. Also the soil surface moved and its final height was up to 1 cm above that at the start. The movements of the objects started within a few hours after temperature shifts around 0 °C with the granite reacting more readily than the wood. It is hypothesized that the movements are related to the thermal properties of the objects and the soil. The experiment was done in parallel with an experiment in clayey silt and the net results in sand show clear parallels to the movements of similar objects in the silt. It is concluded that the material and shape of the object are more important to movements than whether they are embedded in sand or silty clay.

Kolstrup, Else; Thyrsted, Tage

2011-06-01

46

Industrial sand and gravel  

USGS Publications Warehouse

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

Dolley, T. P.

2011-01-01

47

Tar sand  

SciTech Connect

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

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

1990-01-01

48

Laboratory and field evaluation of an underwater sand height gage  

NASA Technical Reports Server (NTRS)

An underwater sand height gage was investigated. This instrument consisted of two transducers, one screened and one unscreened. Laboratory experimentation included static and dynamic tests with three test sands--fine, medium, and coarse. Field tests were conducted at Rudee Inlet, Virginia Beach, Virginia. Test results showed a linear response to up to 10 inches of sand loading. Deviation observed in identical tests appeared to be due to variation in the density of sand. Density differences reflected varying packing styles which, in turn, were a consequence of grain size and flow regime. Further evaluations of the sand height gage reflect this instrument's potential.

Swift, D. J. P.; Mcgrath, D. G.

1972-01-01

49

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

NASA Astrophysics Data System (ADS)

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

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

1998-01-01

50

Effects of fluvial abrasion on shapes of quartz sand grains  

SciTech Connect

The effects of abrasion on the shapes of medium and fine quartz sand grains that are transported through a 300-mi (500-km) stretch of the Mississippi River were determined by Fourier grain-shape measurement and scanning electron microscopy. The results indicate that the abrasion of medium and fine quartz sand grains in the low-gradient stream does not significantly affect their source-inherited shapes.

Peterson, M.; Mazzullo, J.

1987-09-01

51

Offshore sand prospecting in : History and recent efforts  

Microsoft Academic Search

Sea Engineering, Inc. (SEI) has continued long-standing efforts to find exploitable offshore sand resources for the purpose of nourishing Hawaii's beaches. Investigations by University of Hawaii researchers in the 1970's established the potential presence of large bodies of sand in ancient offshore alluvial channels and wave-cut terraces. Sampling efforts showed that much of the sand was too fine-grained to be

James H. Barry

2011-01-01

52

The extraction of bitumen from western tar sands. Annual report  

SciTech Connect

Topics discussed include: characterization of bitumen impregnated sandstone, water based tar sand separation technology, electrophoretic characterization of bitumen and fine mineral particles, bitumen and tar sand slurry viscosity, the hot water digestion-flotation process, electric field use on breaking water-in-oil emulsions, upgrading of bitumens and bitumen-derived liquids, solvent extraction.

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

1990-07-01

53

The extraction of bitumen from western tar sands  

SciTech Connect

Topics discussed include: characterization of bitumen impregnated sandstone, water based tar sand separation technology, electrophoretic characterization of bitumen and fine mineral particles, bitumen and tar sand slurry viscosity, the hot water digestion-flotation process, electric field use on breaking water-in-oil emulsions, upgrading of bitumens and bitumen-derived liquids, solvent extraction.

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

1990-07-01

54

Creating Sand Dunes  

NSDL National Science Digital Library

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

1998-01-01

55

Industrial sand and gravel  

USGS Publications Warehouse

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

Dolley, T. P.

2012-01-01

56

Industrial sand and gravel  

USGS Publications Warehouse

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

Dolley, T. P.

2013-01-01

57

Sand Castle Saturation  

NSDL National Science Digital Library

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

Twin Cities Public Television, Inc.

2005-01-01

58

Critical State of Sand Matrix Soils  

PubMed Central

The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, ?, and ?. The range of the value of M, ?, and ? is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

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

2014-01-01

59

CONTRACTOR REPORT SAND927005  

E-print Network

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

60

China Dust and Sand  

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

2013-04-16

61

Mineral Sands Down Under  

NSDL National Science Digital Library

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

62

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

Microsoft Academic Search

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

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

1999-01-01

63

Fine Travel  

NSDL National Science Digital Library

FineTravel Magazine, produced by Louis Bignami and Big-Ray Publications, is a webzine aimed "at the traveler, not the tourist." It contains first person account feature articles about interesting nooks and crannies of various travel destinations in the US and around the world. Updated weekly, it features a searchable and browsable archive of past FineTravel articles, as well as pointers to airline information, books and videos, and resorts. It is an informative and entertaining site for the Internaut interested in travel.

1995-01-01

64

Development of a novel electro-dialysis based technique for lead removal from silty clay polluted soil.  

PubMed

In this study, a novel electro-dialysis based technique has been developed and used to treat a silty clay soil polluted by lead. The effect of chemical reagents, i.e. tap water at pH 4 (reagent 1) and sodium acetate at pH 5 (reagent 2), on enhancing electro-dialysis extraction of lead from the tested soil was examined. Specimens were prepared by mixing soil with 1000 ppm of lead and were compacted in the dialysate at predetermined dry density and moisture content. Then, specimens were subjected to a predetermined level of current. In the dialysate compartment, anions and cations were removed by charge transport in opposite directions to the anodic and cathodic cells. Meanwhile, in the anodic and cathodic cells, ion concentrations were increased. Thus, concentrated electrolyte streams were produced in alternating cells and cleaned soils were obtained in the dialysate. Both soil pH and lead concentrations were uniformly distributed within the compacted soil specimen during testing. Total lead removal of 80 and 92% was obtained for reagents 1 and 2, respectively. The high removal efficiency was attributed to the separation of electrode reactions from the soil and inclusion of ion selective membranes (ISM), which restrict the movement of counter charged species. PMID:11893427

Mohamed, A M O

2002-03-29

65

Foundry sand reclamation  

Microsoft Academic Search

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

A. J. Filipovitch; J. M. Bleuenstein

1984-01-01

66

Industrial sand and gravel  

USGS Publications Warehouse

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

Dolley, T. P.

2006-01-01

67

Comparison of natural and manufactured fine aggregates in cement mortars  

Microsoft Academic Search

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

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

2007-01-01

68

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

NASA Astrophysics Data System (ADS)

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.

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

69

"Sand Boil" on Bay Bridge  

USGS Multimedia Gallery

"Sand boil" or sand volcano measuring 2 m (6.6 ft) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction). Vented sand contains-marine shell f...

2009-01-26

70

Process and apparatus for recovery of oil from tar sands  

SciTech Connect

A crude oil product is extracted from a tar sand by first crushing the tar sand as mined and then fine grinding the crushed material in a grinding mill in the presence of a cleansing liquid, such as an aqueous solution of a caustic. The resulting slurry is passed into suitable extractor-classifier equipment, such as that shown in U.S. Pat. No. 3,814,336, in which a body of cleansing liquid is maintained. Agitation of the slurry in such maintained body of cleansing liquid substantially completes removal of the bituminous matter from the sand, and the resulting crude oil and cleansing liquid phase is discharged separately from the sand solid phase. The liquid phase is treated for the removal of residual sand particles and for the separation of residual cleansing liquid from the crude oil. The cleansing liquid so recovered is recycled and the crude oil is passed to further processing or for use as such.

Brewer, J.C.

1982-11-30

71

Dynamic Sand Dunes  

Microsoft Academic Search

When sand falling in the spacing between two plates goes past an obstacle, a dynamic dune with a parabolic shape and an inner triangular region of nonflowing or slowly creeping sand forms. The angle of the triangular zone increases with the height of the dune and saturates at a value determined by the geometry of the cell. The width of

Y. Amarouchene; J. F. Boudet; H. Kellay

2001-01-01

72

Treatment response of cutaneous leishmaniasis due to Leishmania aethiopica to cryotherapy and generic sodium stibogluconate from patients in Silti, Ethiopia.  

PubMed

Cutaneous leishmaniasis in Ethiopia is caused mainly by Leishmania aethiopica. In this study, the response of L. aethiopica to sodium stibogluconate (SSG) and liquid nitrogen in Silti has been investigated. Patients were divided into two groups by the treating physician and were treated with either liquid nitrogen or SSG. Punch biopsy samples were collected from 54 patients with mean age of 20.61 (± 9.87 SD) years for histological characterization. The histological spectrum found to be type-1, type-2, type-3 and type-4 were 37.0%, 3.7%, 37.0% and 22.2% respectively. One hundred and three patients with a mean age of 18.4 (± 11.7 SD) years were treated with liquid nitrogen. The mean duration of the lesions before the onset of treatment was 8.5 months (± 6.7 SD). Of the 103 patients 80.6% (83/103) were cured, 13.6% (14/103) were dropouts and 5.8% (6/103) did not respond. Twenty patients with a mean age of 19.55 (+1.64 SD) years were treated with Pentostam on conventional dose. Of the 20 patients 85.0% (17/20) were cured, 10.0% (2/20) were unresponsive and 5.0% (1/20) were dropouts. The per protocol cure rate for cryotherapy and Pentostam was 93.3% and 89.5% respectively. Hence, liquid nitrogen can be used as one of the treatment options especially in resource poor settings. PMID:22503475

Negera, Edessa; Gadisa, Endalamaw; Hussein, Jemal; Engers, Howard; Kuru, Teklu; Gedamu, Lashitew; Aseffa, Abraham

2012-08-01

73

Sand dunes on the central Delmarva Peninsula, Maryland and Delaware  

USGS Publications Warehouse

Inconspicuous ancient sand dunes are present in parts of the central Delmarva Peninsula, Maryland and Delaware. Many dunes are roughly V-shaped, built by northwest winds, especially on the east sides of some of the large rivers. On the uplands, the form and spacing of the dunes are variable. A surficial blanket composed mainly of medium and fine-grained sand-the Parsonsburg Sand-forms both the ancient dunes and the broad plains between the dunes. The sand that forms the dunes is massive and intensely burrowed in the upper part; traces of horizontal or slightly inclined bedding appear near the base. Quartz is the dominant mineral constituent of the sand. Microline is abundant in the very fine to fine sand fraction. The heavy-mineral assemblages (high zircon, tourmaline, rutile) are more mature than in most of the possible source rocks. The most abundant minerals in the clay-sized fraction are dioctahedral vermiculite, kaolinite, illite, montmorillonite, and gibbsite. The first four minerals are common in deposits of late Wisconsin and Holocene age. The gibbsite may be detrital, coming from weathered rocks of Tertiary age. The soil profile in the dune sand is weakly to moderately developed. At or near the base of the Parsonsburg Sand are peaty beds that range in age from about 30,000 to about 13,000 radiocarbon years B.P. Microfloral assemblages in the peaty beds suggest that the dunes on the uplands formed in a spruce parkland during the late Wisconsin glacial maximum. The river dunes may also be of late Wisconsin age, but could be Holocene.

Denny, Charles Storrow; Owens, James Patrick

1979-01-01

74

Industrial sand and gravel  

USGS Publications Warehouse

Domestic production of industrial sand and gravel in 2009 was about 27 Mt (30 million st), declining by 10 percent compared with 2008. Certain end uses of industrial sand and gravel, such as foundry and glassmaking sand, may have declined by a factor greater than 10 percent in 2009. U.S. apparent consumption was 24.7 Mt (27.2 million st) in 2009, down by 10 percent from the previous year, and imports declined to 83 kt (91,000 st).

Dolley, T. P.

2010-01-01

75

Quick Sands Effect on Desert Lands - Example of Filtration Stability Loss  

NASA Astrophysics Data System (ADS)

The aim of the study was to analyze the loss of filtration stability of fine desert sands due to the air flow caused by temperature difference. The loss of stability induces the effect of so called "quick sands". Therefore, the calculations of air filtration through the loose sand medium in dry desert climate are presented. FlexPDE v.6. software was used for numerical calculation based on FEM.

Strzelecki, Micha?

2013-03-01

76

Sand boils without earthquakes  

USGS Publications Warehouse

Sedimentary deformation caused by liquefaction has become a popular means for inferring prehistoric strong earthquakes. This report describes a new mechanism for generating such features in the absence of earthquakes. Sand boils and a 180-m-long sand dike formed in Fremont Valley, California, when sediment-laden surface runoff was intercepted along the upslope part of a 500-m-long preexisting ground crack, flowed subhorizonally in the crack, and then flowed upward in the downslope part of the crack where it discharged as sand boils on the land surface. If the sand boils and their feeder dike were stratigraphically preserved, they could be misinterpreted as evidence for earthquake-induced liquefaction. -Authors

Holzer, T. L.; Clark, M. M.

1993-01-01

77

Vent of Sand Volcano  

USGS Multimedia Gallery

Vent of sand volcano produced by liquefaction is about 4 ft across in strawberry field near Watsonville. Strip spanning vent is conduit for drip irrigation system. Furrow spacing is about 1.2 m (4 ft) on center....

2009-01-26

78

Sand consolidation methods  

SciTech Connect

Methods are provided for selectively consolidating sand grains within a subterranean formation. First an acidic salt catalyst such as ZnCl/sub 2/ is injected into the subterranean formation, wherein the acidic salt catalyst is adsorbed to the surface of the sand grains. Next a polymerizable resin composition such as furfuryl alcohol oligomer is introduced into the well formation. Polymerization of the resin occurs upon exposure to the elevated well temperatures and contact with the acid salt catalyst adsorbed to the sand grains. The polymerized resin serves to consolidate the surfaces of the sand grains while retaining permeability through the pore spaces. An ester of a weak organic acid is included with the resin compositions to control the extent of a polymerization by consuming the water by-product formed druing the polymerization reaction.

Friedman, R.H.

1984-01-24

79

Magic Sand Movie  

NSDL National Science Digital Library

This document from the Midwest Regional Center for Nanotechnology Education (NANO-LINK) is intended to be used with the other materials in the "magic sand" series of classroom lessons, which are available here. This resource is a 4 minute video demonstrating the magic sand experiment. In this experiment, students "will explore how the properties of a substance at the molecular level affects the way that it reacts and behaves."

2013-07-03

80

Sand control in wells with gas generator and resin  

SciTech Connect

This patent describes a method of treating a wellbore having formation perforations for controlling sand and other fine materials. It comprises positioning a quantity of fluid resin material in alignment with the formation perforations of the wellbore; positioning a gas generator in proximity with the fluid resin material; actuating the gas generator to increase wellbore pressure in a substantially instantaneous manner to a pressure substantially in excess of well pressure to force the fluid resin material from the wellbore into the formation perforations; and subsequently polymerizing the resin material to form a consolidated, porous, permeable matrix which retains the sand and other fine materials while permitting the flow of production fluid into the wellbore. This paper also describes a method of treating a wellbore having formation perforations for controlling sand and other fine materials. It comprises positioning a coiled tubing, having a valve and gas generator attached thereto, so that the valve is positioned in a predetermined location relative to the bottom formation perforation; injecting a predetermined amount of fluid resin material through the coiled tubing and valve into the wellbore; raising the gas generator to a position across the formation perforations and in proximity with the fluid resin material; actuating the gas generator to force the fluid resin material into the formation perforations; and thereafter polymerizing the previously fluid resin material to form a consolidated, porous, permeable matrix which retains the sand and other fine materials while permitting the flow of production fluid into the wellbore.

Dees, J.M.

1992-04-07

81

City-swallowing Sand Dunes  

NSDL National Science Digital Library

At this Science at NASA site, you'll learn about the physics of sand movement and the research done to understand mechanisms of dune migration. The physics and the landforms are interesting because granular materials like sand show properties of both solids and fluids, including saltation, sheet flow, and avalanches. This site provides a summary of the physics involved along with photographs of sand dunes on Mars, close-ups of sand particles, and a sand dune advancing on a town.

Bell, Trudy E.

2007-06-19

82

Ganges Chasma Sand Sheet  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

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

Today's sand sheet is located in the Ganges Chasma portion of Valles Marineris. As with yesterday's image, note that the dune forms are seen only at the margin and that the interior of the sand sheet at this resolution appears to completely lack dune forms.

Image information: VIS instrument. Latitude -6.4, Longitude 310.7 East (49.3 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2005-01-01

83

Dynamic Sand Dunes  

NASA Astrophysics Data System (ADS)

When sand falling in the spacing between two plates goes past an obstacle, a dynamic dune with a parabolic shape and an inner triangular region of nonflowing or slowly creeping sand forms. The angle of the triangular zone increases with the height of the dune and saturates at a value determined by the geometry of the cell. The width of the dune, related to the radius of curvature at the tip, shows universal features versus its height rescaled by geometrical parameters. The velocity profile in the flowing part is determined and found to be nonlinear. The parabolic shape can be accounted for using a simple driven convection-diffusion equation for the interface.

Amarouchene, Y.; Boudet, J. F.; Kellay, H.

2001-05-01

84

Sand ripples and dunes 1 Sand ripples and dunes  

E-print Network

Sand ripples and dunes 1 Sand ripples and dunes Franc¸ois Charru Institut de M´ecanique des Fluides of environments: in water channels, rivers and coastal ar- eas (Best 2005), in deserts on Earth (Bagnold 1941, Pye

85

Sand consolidation methods  

Microsoft Academic Search

A method is described for consolidating unconsolidated mineral particles including sand in a subterranean petroleum formation penetrated by a well in fluid communication with at least a portion of the formation. The method consists of: (a) providing a fluid comprising a polymerizable resin, a polar organic diluent for the resin, and an oil soluble acid catalyst capable of causing polymerization

R. H. Friedman; B. W. Surles

1989-01-01

86

Building with Sand  

ERIC Educational Resources Information Center

Children playing in damp sand invariably try to make a tower or a tunnel. By providing experiences with a variety of materials, alone and together, teachers set up the conditions for children to learn through their senses and ensure that a class approaches a topic with a common set of experiences to build on. Learning about the properties of…

Ashbrook, Peggy

2010-01-01

87

Extracting Oil From Tar Sands  

NASA Technical Reports Server (NTRS)

Recovery of oil from tar sands possible by batch process, using steam produced by solar heater. In extraction process, solar heater provides steam for heating solvent boiler. Boiling solvent removes oil from tar sands in Soxhlet extractor.

Ford, L. B.; Daly, D.

1984-01-01

88

Northern Sand Sea  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

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

This VIS image was taken at 82 degrees North latitude during Northern spring. The image is completely dominated by dunes. In sand seas, it is very common for a single type of dune to occur, and for a single predominate wind to control the alignment of the dunes.

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

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2005-01-01

89

Determination of fine-scale vertical distribution of microbes and meiofauna in an intertidal sediment  

Microsoft Academic Search

A simple sampling device is described which produces thin (1 mm) sections of sediment cores. The sampler has been tested on fine sand of an intertidal sandflat and used to study the vertical distribution, over part of a tidal cycle in August, 1981, of migrating algae in the surface 20 mm of sand. Two species of Diplonies and one of

I. R. Joint; J. M. Gee; R. M. Warwick

1982-01-01

90

Special report: Athabasca tar sands  

Microsoft Academic Search

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

W. A. Bachman; D. H. Stormont

1967-01-01

91

Oil sands tailings leachability and toxicity evaluation  

SciTech Connect

Fine tailings disposal and reclamation is a major issue facing the oil sands mining and extraction industry. Government regulations dictate that reclamation must return the site to a level of self-sustaining biological capability which approximates the natural condition. A two-phase laboratory program has been completed to investigate the suitability of alternative reclamation materials. For the first phase of the study, chemical and toxicological analyses were carried out on 13 different reclamation and reference materials (solid phase and extractions). Seedling emergence, nematode maturation, algal growth and bacterial luminescence for leachate samples showed a range of sensitivities in response to the tested materials, although phytotoxicity tests were generally the most sensitive. With the exception of one test material, high toxicity ratings were consistent with that expected from the chemical data. The second phase of the study focused on the evaluation of chemical and toxicological conditions in leachate water generated using bench-scale column percolation tests. Leachate water equivalent to 10 pore volume replacements was generated and temporal variations in toxicity and chemistry monitored. Similar to phase 1 findings, phytotoxicity tests were the most sensitive tests to leachate waters. For most materials tested, most toxicity was removed after 2--3 porewater replacements. More persistent toxicity was noted for samples containing bitumen (e.g., fine tails and oil sands). No clear correspondence was noted between chemical concentrations and toxicity in leachate waters.

Gulley, J.R. [Suncor Inc., Fort McMurray, Alberta (Canada). Oil Sands Group; Hamilton, H.R.; Taylor, B. [Golder Associates Ltd., Calgary, Alberta (Canada)

1995-12-31

92

Shear Band Formation in Plane Strain Experiments of Sand  

NASA Technical Reports Server (NTRS)

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

Alshibli, Khalid A.; Sture, Stein

2000-01-01

93

Sand Sieve Analysis  

NSDL National Science Digital Library

John R. Anderson of Georgia Perimeter College has authored this lab experiment on grain size sorting in which students learn about performing a sieve analysis of sand and produce various graphs to represent the data collected. Included are equations for making the graphs and basic information on the importance of sieve analysis and the four useful statistical measurements used to make the graphs. This is a great resource to either the creation or enhancement of an instructors curriculum on this topic.

Anderson, John

2009-05-21

94

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

SciTech Connect

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

Ross, Steven B.; Young, Jonathan

2005-09-28

95

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

NASA Astrophysics Data System (ADS)

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

Benaafi, Mohammed; Abdullatif, Osman

2014-05-01

96

Method of repairing a wellbore liner for sand control  

SciTech Connect

This patent describes a method of repairing a damaged wellbore liner for controlling sand and other fine materials. It comprises: positioning a quantity of fluid resin material in alignment with the portion of the wellbore liner to be repaired; positioning a gas generator in proximity with the fluid resin material; actuating the gas generator to increase wellbore pressure in a substantially instantaneous manner to a pressure substantially in excess of well pressure to force the fluid resin material from the wellbore into the damaged area of the wellbore liner; and subsequently polymerizing the resin material to form a consolidated, porous permeable matrix that allows the flow of production fluid into the well while preventing the flow of sand, or other fine materials into the well through the previously damaged area of the wellbore liner.

Dees, J.M.

1992-10-13

97

ACULEATA HYMENOPTERA OF SAND MOUNTAIN AND BLOW SAND MOUNTAINS, NEVADA  

E-print Network

vegetation was Atriplex con fertifolia (Torr. & Frem.), Tetradymia tetra meres (Blake), Chrysothamnus viscidiflorus (Hookl), Astragalus lentiginousus Dougl., and Psoralea lanceolata (Pursh.), and at Sand Mountain

Hanks, Lawrence M.

98

The impact of fine aggregate characteristics on asphalt concrete pavement design life  

Microsoft Academic Search

The development of the Mechanistic–Empirical Pavement Design Guide (MEPDG) provides an opportunity to simulate the performance of pavements. This paper considers the impact of fine aggregate on the predicted performances of pavements by simulating the performance differences between pavement mixes prepared with different sources of fine aggregate with different gradations using the MEPDG. A natural and four manufactured sands from

Tamer M. Breakah; Jason P. Bausano; R. Christopher Williams; Stan Vitton

2011-01-01

99

Paleobiology of the Sand Beneath the Valders Diamicton at Valders, Wisconsin  

NASA Astrophysics Data System (ADS)

Previously undescribed pollen, plant macrofossils, molluscs, and ostracodes were recovered from a 2.5-m-thick glaciolacustrine unit of silty sand and clay at Valders, Wisconsin. The interstadial sediment was deposited about 12,200 14C yr B.P. after retreat of the Green Bay lobe that deposited diamicton of the Horicon Formation, and before advance of the Lake Michigan lobe that deposited the red-brown diamicton of the Valders Member of the Kewaunee Formation. Fluctuations of abundance of Candona subtriangulata, Cytherissa lacustris,and three other species define four ostracode biozones in the lower 1.7 m, suggesting an open lake environment that oscillated in depth and proximity to glacial ice. Pollen is dominated by Piceaand Artemisia,but the low percentages of many other types of long-distance origin suggest that the terrestrial vegetation was open and far from the forest border. The upper part of the sediment, a massive sand deposited in either a shallow pond or a sluggish stream, contains a local concentration of plant macrofossils. The interpretation of a cold open environment is supported by the plant macrofossils of more than 20 species, dominated by those of open mineral soils ( Arenaria rubella, Cerastium alpinumtype, Silene acaulis, Sibbaldia procumbens, Dryas integrifolia, Vaccinium uliginosumvar. alpinum, Armeria maritima,etc.) that in North America occur largely in the tundra and open tundra-forest ecotone of northern Canada. Ice-wedge casts occur in the sand.

Maher, Louis J.; Miller, Norton G.; Baker, Richard G.; Curry, B. Brandon; Mickelson, David M.

1998-03-01

100

Laboratory singing sand avalanches.  

PubMed

Some desert sand dunes have the peculiar ability to emit a loud sound up to 110 dB, with a well-defined frequency: this phenomenon, known since early travelers (Darwin, Marco Polo, etc.), has been called the song of dunes. But only in late 19th century scientific observations were made, showing three important characteristics of singing dunes: first, not all dunes sing, but all the singing dunes are composed of dry and well-sorted sand; second, this sound occurs spontaneously during avalanches on a slip face; third this is not the only way to produce sound with this sand. More recent field observations have shown that during avalanches, the sound frequency does not depend on the dune size or shape, but on the grain diameter only, and scales as the square root of g/d--with g the gravity and d the diameter of the grains--explaining why all the singing dunes in the same vicinity sing at the same frequency. We have been able to reproduce these singing avalanches in laboratory on a hard plate, which made possible to study them more accurately than on the field. Signals of accelerometers at the flowing surface of the avalanche are compared to signals of microphones placed above, and it evidences a very strong vibration of the flowing layer at the same frequency as on the field, responsible for the emission of sound. Moreover, other characteristics of the booming dunes are reproduced and analyzed, such as a threshold under which no sound is produced, or beats in the sound that appears when the flow is too large. Finally, the size of the coherence zones emitting sound has been measured and discussed. PMID:19880153

Dagois-Bohy, Simon; Ngo, Sandrine; du Pont, Sylvain Courrech; Douady, Stéphane

2010-02-01

101

Investigation of guided waves propagation in pipe buried in sand  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

102

Recycling of PET bottles as fine aggregate in concrete.  

PubMed

An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility. PMID:20176466

Frigione, Mariaenrica

2010-06-01

103

Recycling of PET bottles as fine aggregate in concrete  

SciTech Connect

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

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

2010-06-15

104

The use of fly ash-stabilized sand mixtures as capping materials for landfills  

SciTech Connect

An investigation was made to study the suitability of using coal fly ash-stabilized sand mixtures as capping materials for sanitary landfills. Sand mixtures stabilized with 15 and 20% Class C fly ash were investigated. Compaction, permeability, unconfined compressive strength, freeze-thaw, and wet-dry tests were conducted on both mixtures. Results indicate that fly ash-stabilized sand blends can be used as capping materials in areas where fine-grained soils are not available. Data indicate that the 20% fly ash-stabilized sand mixture will yield a better performance than sand mixtures stabilized with 15% fly ash. Increased strength, reduced permeability, and increased resistance to freeze-thaw and wet-dry cycles are some of the benefits obtained by using the high fly ash content.

Taha, R.A. [Montana State Univ., Bozeman, MT (United States). Dept. of Civil Engineering; Pradeep, M.R. [South Dakota State Univ., Brookings, SD (United States). Dept. of Civil Engineering

1997-12-31

105

Re-usage of waste foundry sand in high-strength concrete.  

PubMed

In this study, the potential re-use of waste foundry sand in high-strength concrete production was investigated. The natural fine sand is replaced with waste foundry sand (0%, 5%, 10%, and 15%). The findings from a series of test program has shown reduction in compressive and tensile strengths, and the elasticity modulus which is directly related to waste foundry inclusion in concrete. Nevertheless the concrete with 10% waste foundry sand exhibits almost similar results to that of the control one. The slump and the workability of the fresh concrete decreases with the increase of the waste foundry sand ratio. Although the freezing and thawing significantly reduces the mechanical and physical properties of the concrete. The obtained results satisfies the acceptable limits set by the American Concrete Institute (ACI). PMID:20219339

Guney, Yucel; Sari, Yasin Dursun; Yalcin, Muhsin; Tuncan, Ahmet; Donmez, Senayi

2010-01-01

106

WASTEWATER TREATMENT OVER SAND COLUMNS  

E-print Network

93/0096 WASTEWATER TREATMENT OVER SAND COLUMNS TREATMENT YIELDS, LOCALISATION OF THE BIOMASS Domestic wastewater treatment by infiltration-percolation is a process that becomming common in France, a greater depth for desinfection purposes. KEYWORDS Wastewater treatment, Infiltration-percolation. Sand

Paris-Sud XI, Université de

107

Non-aeolian sand ripples  

Microsoft Academic Search

By examining the initial stages of the impact of a granular jet on a flat horizontal solid surface we evidenced the existence of oscillatory sand fronts. These oscillations give rise to a novel mechanism for the formation of ripples on sand surfaces. We here show that as the front advances, its slope changes periodically in time, leaving behind a succession

J. F. Boudet; Y. Amarouchene; B. Bonnier; H. Kellay

2005-01-01

108

Exploring Magic Sand  

NSDL National Science Digital Library

Nanotechnology is an area of science and engineering that occurs at the atomic and molecular level. This is certainly a difficult concept to grasp. This website, presented by The National Infrastructure Network, highlights many critical concepts to understanding this smaller scale. By using a product called "Magic Sand," the activity "will explore how the properties of a substance at the molecular level affects the way that it reacts and behaves." Additionally, students will explore nanotechnology as an emerging and interdisciplinary field. The experiment will show students how developments in the field can improve devices, materials, and structures we use on a daily basis. A student and teacher guide is provided with the lab. Overall, this is a great exercise for any science classroom interested in the workings of nanotechnology.

2009-01-16

109

Atlas of Dutch drift sands  

NASA Astrophysics Data System (ADS)

The Netherlands is well known for its aeolian landscapes. Frequent storms during the High Middle Ages (1000-1300 AD) reactivated Pleistocene coversands and river dunes and are responsible for the formation of the Holocene drift sands at a scale which is unique for Europe. A hypothesized relationship with farmer practices for making plaggensoils has recently been refuted, because drift sand formation began centuries earlier. The coastal dune belt with their parabolic dunes dates from the same period as the drift sand. An estimate of the extent of drift sands can be made from soil maps: drift sands are too young to show much profile development (Regosols). With this method Koster estimated the maximum extent of Holocene drift sands in the Netherlands to be about 800 km2 (Koster 2005). Laser altimetry allows a more precise estimate of the total surface affected by wind from the characteristic relief patterns produced by the Holocene wind, which is different from the smooth surface of cover sand deposits. Laser altimetry has been used before to investigate the mechanism of drift sand formation (Jungerius & Riksen 2010). Most of the surface affected by wind is not active anymore, but the tell-tale rough surface survived ages of different landuse. The total affected surface amounts to 825 km2. It is noteworthy that both methods give comparable results. We recorded a total number of 367 of affected areas of varying shapes, ranging in size from 1.6 ha to a large complex of drif sands of 7,119.5 ha. As is to be expected from their mode of origin, most occurrences are associated with cover sands, and with river dunes along the river Meuse and smaller rivers in other parts of the country. Particularly the final phases of cover sand and river dunes that show more relief as parabolic dunes were affected. There are also small aeolian deposits at the lee side blown from fallow agricultural fields but they are (sub)recent. Most of the relief is irregular, but the larger occurrences associated with push moraines show that drift sand occurs in elongated cells that are parallel to the prevailing SW wind. Their internal structure reflects the characteristic sequence of geomorphological processes: deflation dominant in the south-west, transport and accumulation towards the north east. Literature • Jungerius, P.D., Riksen, M.J.P.M., 2010. Contribution of laser altimetry images to the geomorphology of the Late Holocene inland drift sands of the European Sand Belt. Baltica 23, 1: 59-70. • Koster EA. 2005. Aeolian environments. In The physical Geography of Western Europe, Koster EA (ed). Oxford Regional Environments, Oxford University Press;139-160.

Riksen, Michel; Jungerius, Pieter

2013-04-01

110

Sand and Water  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 7 November 2003

This image shows a relatively small crater (35 km across) in the heavily cratered terrain of the southern highlands. At the midlatitudes, this area is known both for its water-formed gullies and its sand dunes. This crater shows spectacular examples of both. In fact, the gullies running down the northern edge of the crater made it to the cover of Science magazine on June 30, 2000. The large dark spot in the floor of the crater is sand that has accumulated into one large dune with a single curvilinear crest.

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

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

111

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

NASA Astrophysics Data System (ADS)

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

Venditti, Jeremy G.; Church, Michael

2014-09-01

112

Modeling the electrical transfer in a mixture of disperse dielectric and finely disperse solid- or liquid-phase conductor  

Microsoft Academic Search

The dependence of the electrical conductivity of a mixture of finely disperse graphite with quartz sand and moist quartz sand on the composition is investigated. It is shown that, in the region of critical and near-critical concentrations of the conducting component, the dependence is satisfactorily described by two power-law equations of flow theory with two different threshold values of the

T. G. Mikhailova; L. A. Bel'kova; V. M. Nesterov; V. V. Zagoskin; E. A. Zamotrinskaya

1984-01-01

113

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

USGS Publications Warehouse

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

Nordin, Carl F.; Perez-Hernandez, David

1989-01-01

114

Optimization of the peroxy acid treatment of alpha-methylnaphthalene and benzo[a]pyrene in sandy and silty-clay sediments.  

PubMed

The majority of polycyclic aromatic hydrocarbons (PAHs) released to the environment come from anthropogenic sources involving the incomplete combustion of organic compounds. Several techniques are available for the degradation of PAHs. Among the abiotic/biotic processes used to degrade PAHs, an alternative strategy utilizing a primary chemical oxidative step to be combined with a biological was created. The degradation of alpha-methylnaphthalene and benzo[a]pyrene using an advanced oxidation process was optimized over a period of 24 h by varying the ratio of acetic acid to hydrogen peroxide, the compounds that form peroxy acids. The optimization process was performed using sandy and silty-clay sediment types. Gas chromatography equipped with a flame ionization detector was used to determine the varied rates of degradation depending on acetic acid:hydrogen peroxide ratios and the characteristics of the sediment sample. Reduction of 20-90% of alpha-methylnaphthalene and benzo[a]pyrene was observed when 2-5 mL of hydrogen peroxide was used, respectively. A peracetic acid solution (e.g., a commercial form of acetic acid and hydrogen peroxide) was used to compare the results from the peroxy acid experiments. In all the experiments, peracetic acid was more reactive than the combination of acetic acid and hydrogen peroxide. Acetic acid, deionized water, and hydrogen peroxide served as controls and demonstrated minimal degradation over the time course study. Therefore, the use of a peroxy acid process to target electron dense pollutants may have a great utility. PMID:15046359

N'Guessan, Adeola L; Carignan, Todd; Nyman, Marianne C

2004-03-01

115

Sand, Syrup and Supervolcanoes  

NASA Astrophysics Data System (ADS)

Supervolcanic eruptions are amongst the most awesome events in the history of the Earth. A supervolcano can erupt thousands of cubic kilometers of ash devastating entire countries and changing the climate for decades. During the eruption, the magma chamber partially empties and collapses. As the chamber collapses at depth, a massive subsidence pit develops at the surface, called a caldera, some calderas can be the size of the entire San Francisco Bay Area. Fortunately, a supervolcano of this size has not erupted since the development of modern man. Due to the infrequency and massive scale of these eruptions, volcanologists do not yet fully understand how calderas form and how the eruption is affected by the roof collapse and vice versa. Therefore, simple analogue experiments are amongst the best ways to understand these eruptions. We present two of these experiments that can be fun, cheap, and helpful to high school and university instructors to demonstrate caldera formation. The first experiment illustrates how magma chamber roofs collapse to produce different style calderas, the second experiment demonstrates how the magma in the chamber affects the collapse style and magma mixing during a supervolcanic eruption. The collapse of a magma chamber can be demonstrated in a simple sandbox containing a buried balloon filled with air connected to a tube that leads out of the sandbox. At this small scale the buried balloon is a good analogue for a magma chamber and sand has an appropriate strength to represent the earths crust. Faults propagate through the sand in a similar way to faults propagating through the crust on a larger scale. To form a caldera just let the air erupt out of the balloon. This experiment can be used to investigate what controls the shape and structure of calderas. Different shaped balloons, and different burial depths all produce sand calderas with different sizes and structures. Additionally, experiments can be done that erupt only part of the volume of the balloon. These sandbox experiments can be compared to natural calderas and help us understand their internal structure. The second experiment helps us understand how magma behaves during collapse. For this experiment we allowed dense cylindrical blocks to sink into syrup solutions filled with poppy seeds. We mix the syrup with warm water to reduce its viscosity. A series of sinking experiments can be done at different viscosities to investigate different regimes of fluid flow. A key parameter used to the character of the flow of magma is the Reynolds number, the ratio between inertial and viscous forces. The experiments show how the Reynolds number of the magma affects the speed and the style that the block sinks, and also how the magma behaves in the chamber. Fast subsidence in low viscosity fluid (high Reynolds numbers) produces seed vortices in the syrup, indicating mixing. This experiment helps us understand the interplay between eruption and collapse and why mixed magma frequently erupts from calderas. These two simple experiments not only demonstrate caldera formation, but also can be used to get quantative information about the processes governing caldera formation.

Kennedy, B.; Jellinek, M.; Stix, J.

2006-12-01

116

Which fine-tuning arguments are fine?  

Microsoft Academic Search

The argument from naturalness is widely employed in contemporary quantum field theory. Essentially a formalized aesthetic criterion, it received a meaning in the debate on the Higgs mechanism, which goes beyond aesthetics. We follow the history of technical definitions of fine tuning at the scale of electroweak symmetry breaking. It is argued that they give rise to a special interpretation

Alexei Grinbaum

2009-01-01

117

Dewatering of fine coal  

SciTech Connect

The factors which control the dewatering of fine coal by gravity/centrifugal drainage and by gas displacement (vacuum/hyperbaric filtration) are evaluated. A generalized model is presented and used to describe dewatering kinetics and to establish dewatering limits. Applications to the design of dewatering systems for fine coal dewatering are discussed.

Hogg, R. [Mineral Processing Section, University Park, PA (United States)

1995-10-01

118

Sand control system  

SciTech Connect

A method is described for controlling sands in a wellbore, the method comprising the steps of: introducing an amount of particles into the wellbore, introducing a tubular string into the particles and moving the string downwardly in the particles, the tubular string having swivel means for rotatably connecting an entry tool to the string, the swivel means connected between the string and the entry tool, the swivel means having a diameter no greater than the diameter of the string, the entry tool mounted to the swivel means for relative rotation. The tool has auger means for facilitating the introduction of the string into the particles. A tool for facilitating the introduction of a tubular string into an accumulation of particles in a wellbore has perforations for production. The tool comprises: body means; rotative connection means for rotatably connecting the body means to the string for relative rotation; the rotative connection means connects between the string and the body means and has a diameter no greater than the diameter of the string; and auger means connects to the body means for augering into the particles and for facilitating the movement of particles into the perforations.

Guidry, J.P.; Gavranovic, L.R.C.

1987-07-21

119

Saltation of Non-Spherical Sand Particles  

PubMed Central

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. PMID:25170614

Wang, Zhengshi; Ren, Shan; Huang, Ning

2014-01-01

120

Simulating Sand Behavior through Terrain Subdivision and Particle Refinement  

NASA Astrophysics Data System (ADS)

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

Clothier, M.

2013-12-01

121

Laboratory compaction of cohesionless sands  

E-print Network

A total of 62 cohesiveness sands were tested to rographics. investigate the importance of the water content, grain size distribution, grading of the soil, particle shape, grain crushing during testing and laboratory compaction test method...

Delphia, John Girard

2012-06-07

122

Sound-producing sand avalanches  

NASA Astrophysics Data System (ADS)

Sound-producing sand grains constitute one of nature's more puzzling and least understood physical phenomena. They occur naturally in two distinct types: booming and squeaking sands. Although both varieties of sand produce unexpectedly pure acoustic emissions when sheared, they differ in their frequency range and duration of emission, as well as the environment in which they tend to be found. Large-scale slumping events on dry booming dunes can produce acoustic emissions that can be heard up to 10 km away and which resemble hums, moans, drums, thunder, foghorns or the drone of low-flying propeller aircraft. These analogies emphasize the uniqueness of the phenomenon and the clarity of the produced sound. Although reports of these sands have existed in the literature for over one thousand years, a satisfactory explanation for either type of acoustic emission is still unavailable.

Sholtz, Paul; Bretz, Michael; Nori, Franco

1997-05-01

123

Non-aeolian sand ripples  

NASA Astrophysics Data System (ADS)

By examining the initial stages of the impact of a granular jet on a flat horizontal solid surface we evidenced the existence of oscillatory sand fronts. These oscillations give rise to a novel mechanism for the formation of ripples on sand surfaces. We here show that as the front advances, its slope changes periodically in time, leaving behind a succession of surface elevations and depressions. A key feature of these oscillations is the interplay between the deposition of mobile sand and the avalanching of the static parts giving rise to a remarkable self-regulating system. These features come out naturally from a simplified version of recently proposed models for the dynamics of sand piles.

Boudet, J. F.; Amarouchene, Y.; Bonnier, B.; Kellay, H.

2005-02-01

124

Sesame fertilization on lakeland sand  

E-print Network

SESAME FERTILIZATION ON LAKELAND SAND A Thesis RAMON HUERTA M. Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1961... Ma/or Sub]ect: Agronomy SESAME FERTILIZATION ON LAKELAND SAND A Thesis RAMON HUERTA M. Approved as to style and content hy: Chairssn of Conunittee Head of partment January 1961 ACKNOWLEDGEMENTS The author wishes to express his sincere...

Huerta, Ramon Moreno

2012-06-07

125

Sedimentology and stratigraphy of tidal sand ridges southwest Florida inner shelf  

SciTech Connect

Detailed investigation of linear shelf sand ridges located off the southwest coast of Florida shows them to be tide-dominated sand bodies. These ridges are remarkably similar to the large sand ridges of the North Sea, and they have abundant apparent analogs in the stratigraphic record, many of which are important petroleum producers. The Florida ridges are asymmetric in profile, about 10 km long, 1 km wide, with relief of 3-4 m with the adjacent sea bed. Extensive tidal current monitoring, sediment distribution patterns and side scan sonar surveys permit characterizing their morphodynamics. Tidal currents show distinct bidirectional patterns with speeds up to 70 cm/s. There is slight flood-dominance, and currents show much higher velocities in the troughs as compared to the crests of the ridges. Megaripples and sand waves are widespread and migrate obliquely across the ridges at opposite directions on the gentle and steep side of the ridge. Shallow, high-resolution seismic data and 39 vibracores din the area of the ridges show a consistent sequence characterized by three ascending Holocene lithofacies: (1) muddy quartz sand with limestone clasts; (2) bioturbated muddy shelly quartz sand; and (3) well-sorted, cross-stratified quartz sand that characterizes the sand ridges themselves. Each of the tidal sand ridges displays a coarsening-upward sequence of fine, well-sorted sand. Small-scale, multidirectional, cross stratification dominates the stratigraphy of the cores in this facies, but megaripple cross stratification is also present. All data indicate that these tidal ridges are good modern analogs for many of the shelf sand bodies in the ancient record, especially the Mesozoic of the mid-continent area.

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

1993-01-01

126

Fine Grained Robotics  

E-print Network

Fine grained robotics is the idea of solving problems utilizing multitudes of very simple machines in place of one large complex entity. Organized in the proper way, simple machines and simple behaviors can lead to emergent ...

Flynn, Anita M.

127

Which Fine-Tuning Arguments Are Fine?  

NASA Astrophysics Data System (ADS)

Fine-tuning arguments are a frequent find in the literature on quantum field theory. They are based on naturalness—an aesthetic criterion that was given a precise definition in the debates on the Higgs mechanism. We follow the history of such definitions and of their application at the scale of electroweak symmetry breaking. They give rise to a special interpretation of probability, which we call Gedankenfrequency. Finally, we show that the argument from naturalness has been extended to comparing different models of the physics beyond the Standard Model and that naturalness in this case can at best be understood a socio-historic heuristic.

Grinbaum, Alexei

2012-05-01

128

Dispersion attendant sodium/hydrogen ion exchange in reservoir sands  

SciTech Connect

Chromatographic lag observed upon injection of dilute alkali into reservoir sands is now well explained in terms of sodium/hydrogen ion exchange. However, the spread of the eluting hydroxide is more extreme than that associated with axial dispersion. The authors postulate an additional mass-transfer resistance caused by molecular diffusion in a microporous clay fraction. A quantitative model for this diffusion resistance is presented that compares favorably with experimental hydroxide histories from a water-saturated Berea sandstone. Both thin-section and scanning electron microscope (SEM) examination of the Berea rock confirm the presence of microporous regions of clay fines.

Jensen, J.A.; Gillis, J.V.; Radke, C.J.

1986-11-01

129

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

USGS Publications Warehouse

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

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

2000-01-01

130

Methanogenic potential of tailings samples from oil sands extraction plants.  

PubMed

Approximately 20% of Canada's oil supply now comes from the extraction of bitumen from the oil sands deposits in northeastern Alberta. The oil sands are strip-mined, and the bitumen is typically separated from sand and clays by an alkaline hot water extraction process. The rapidly expanding oil sands industry has millions of cubic metres of tailings for disposal and large areas of land to reclaim. There are estimates that the consolidation of the mature fine tails (MFT) in the settling ponds will take about 150 years. Some of the settling ponds are now evolving microbially produced methane, a greenhouse gas. To hasten consolidation, gypsum (CaSO4 x 2H2O) is added to MFT, yielding materials called consolidated or composite tailings (CT). Sulfate from the gypsum has the potential to stimulate sulfate-reducing bacteria (SRB) to out-compete methanogens, thereby stopping methanogenesis. This investigation examined three MFT and four CT samples from three oil sands extractions companies. Each was found to contain methanogens and SRB. Serum bottle microcosm studies showed sulfate in the CT samples stopped methane production. However, if the microcosms were amended with readily utilizable electron donors, the sulfate was consumed, and when it reached approximately 20 mg/L, methane production began. Some unamended microcosms were incubated for 372 days, with no methane production detected. This work showed that each MFT and CT sample has the potential to become methanogenic, but in the absence of exogenous electron donors, the added sulfate can inhibit methanogenesis for a long time. PMID:11888160

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

2002-01-01

131

Geology on a Sand Budget  

NSDL National Science Digital Library

Earth science teaches know how frustrating it can be to spend hundreds of dollars on three-dimensional (3-D) models of Earth's geologic features, only to use the models for a few class periods. To avoid emptying an already limited science budget, teachers can use a simple alternative to the expensive 3-D models--sand. Modeling geologic processes and features with sand is an effective way for teachers to promote student understanding of Earth science topics, quickly assess students' prior knowledge, and identify common misconceptions.

Kane, Jacqueline

2004-09-01

132

Fourier grain shape analysis as a tool for indicating batch recoveries of bitumen from Athabasca tar sands  

SciTech Connect

Effects of weight percent fines have been considered in the past as important factors in controlling the recoveries of bitumen from tar sands using batch extractors. However, in the marine sands of the Athabasca deposit, fines break down as a predictor of batch recovery; in some places even low fines tar sands do not yield acceptable batch bitumen recoveries. It was predicted that a sand unit high in rough-surfaced, diagenetically altered grains would yield low primary bitumen recovery. Scanning electron microscopy of the solids from batch extraction tests revealed that quartz grains with very rough, pitted, and overgrown surfaces retain bitumen. Fourier grain-shape analysis was employed to identify tar sand shape types since scanning electron microscopy inspections are time-consuming and expensive. Five grain shape families were so identified and verified by SEM. Fourier grain-shape analysis yields the proportion of high surface area grains in 900 grain samples taken from marine sand intervals of 3 cores. That proportion, plotted versus weight percent primary recovery by batch extraction, indicates that when the proportion of high energy grains exceeds 40%, primary recoveries were less than 80 wt. %. The results suggest the feasibility of predicting recovery in advance of mining, thus permitting adjustments to mining/extraction strategies. It must be kept in mind, however, that extrapolation of bitumen recovery results from bench-scale batch tests to large-scale continuous units is not straightforward.

Smith, M.M.; Ehrlich, R.; Hardin, A.

1983-03-01

133

Sedimentary processes associated with sand and boulder deposits formed by the 2011 Tohoku-oki tsunami at Sabusawa Island, Japan  

NASA Astrophysics Data System (ADS)

This paper reports on the sedimentary processes of sand and boulder deposition at Sabusawa Island, Japan as a result of the 2011 Tohoku-oki tsunami. Boulders were composed of tuffaceous rocks and sourced from an earthquake-triggered slope failure as well as concrete fragments of seawall. They were scattered over the ground surface and did not form boulder ridges, although there was some local imbrication. The boulders were deposited on top of a sand layer indicating that the latter, possibly deposited from bed load, covered the ground surface first. This sand layer probably reduced friction allowing boulders to be transported more easily than might be expected across a hard ground with a high bottom friction. Sand deposits showed landward thinning and fining features, while the boulders showed a landward coarsening (tuffaceous boulders) or a landward fining (concrete boulders), indicating that large clasts were not necessarily scattered randomly but rather might have a clast size gradient with distance inland. These features are explained by the local topographic setting that constrained the directions of incoming and returning tsunami flows. Some clasts at the inland extent of the boulder field were covered by an upward fining sand layer. This feature suggests that the boulders were deposited prior to the suspended sands, with the latter subsequently laid down before the water level dropped below the top of the boulders. Such modern investigations of the sedimentary features of various sizes of grains and clasts immediately after a tsunami provide invaluable data for the reconstruction of inundation processes.

Goto, Kazuhisa; Sugawara, Daisuke; Ikema, Satoko; Miyagi, Toyohiko

2012-12-01

134

Sand and Water Table Play  

ERIC Educational Resources Information Center

The authors observed preschoolers engaged at the sand and water table to determine if math could be found within their play. Wanting to understand how children interact with provided materials and what kinds of math ideas they explore during these interactions, the authors offer practical examples of how such play can promote mathematical…

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

2010-01-01

135

NU Intramural Sports Sand Volleyball  

E-print Network

NU Intramural Sports Sand Volleyball GENERAL RULES: 1. All players must present their valid be responsible for collecting his team's IDs and registering their uniform numbers with the IM staff. 3. 3 Unsportsmanlike Penalties will result in the player leaving the game. Only a team's designated Captain is allowed

Sridhar, Srinivas

136

FINE PARTICLE CHARGING DEVELOPMENT  

EPA Science Inventory

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

137

Dewatering of fine coal  

SciTech Connect

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

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

1991-01-01

138

Regeneration of sand waves after dredging  

Microsoft Academic Search

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

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

2002-01-01

139

Treating tar sands formations with karsted zones  

SciTech Connect

Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX)

2010-03-09

140

Sand reinforced with shredded waste tires  

Microsoft Academic Search

The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce sand. Direct shear tests were conducted on mixtures of dry sand and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, sand matrix unit weight, shred content, shred length, and shred orientation. From results of

Gary J. Foose; Craig H. Benson; Peter J. Bosscher

1996-01-01

141

Spatial Variation of Fine Sediment Infiltration in a Gravel-Bedded River  

NASA Astrophysics Data System (ADS)

Fine sediment infiltration occurs when sand and silt are deposited into void spaces between gravel at the riverbed. Pulses of fine sediment in gravel-bedded rivers can cause extensive fine sediment infiltration, potentially altering river morphodynamics and aquatic ecosystems. The 2008 removal of Milltown Dam from the Clark Fork River near Missoula, Montana and the resulting pulse of fine sediment released from Milltown Reservoir provide a unique opportunity to investigate controls on and the spatial distribution of fine sediment infiltration. Metal contaminants trapped in the reservoir from mining operations upstream provide a geochemical tracer for the fine sediment transported downstream after the dam was removed. From the dam site to 25 km downstream, where a large tributary enters, substantial infiltration of fine sediment has been observed, but infiltration (as well as deposition in side channels, bars, and on the floodplain) has been greatest in a multi-thread reach starting 16 km downstream of the dam, where we focused our data collection. To characterize the volume, stratigraphy, and residence time of infiltrated fine sediments, we collected 16 bulk samples and ten freeze cores and installed and recovered 16 infiltration bags during the 2010 water year. Preliminary analyses suggest greater infiltration of fines in side channels and backwater eddies, as well as persistence of high fines content in the bed material two-and-a-half years after dam removal. Metals analysis of freeze cores at 10-cm intervals is being used to identify whether infiltrated fines originate from contaminated portions of Milltown Reservoir.

Evans, E. G.; Wilcox, A. C.

2010-12-01

142

Permeability predictions for sand-clogged Portland cement pervious concrete pavement systems.  

PubMed

Pervious concrete is an alternative paving surface that can be used to reduce the nonpoint source pollution effects of stormwater runoff from paved surfaces such as roadways and parking lots by allowing some of the rainfall to permeate into the ground below. This infiltration rate may be adversely affected by clogging of the system, particularly clogging or covering by sand in coastal areas. A theoretical relation was developed between the effective permeability of a sand-clogged pervious concrete block, the permeability of sand, and the porosity of the unclogged block. Permeabilities were then measured for Portland cement pervious concrete systems fully covered with extra fine sand in a flume using simulated rainfalls. The experimental results correlated well with the theoretical calculated permeability of the pervious concrete system for pervious concrete systems fully covered on the surface with sand. Two different slopes (2% and 10%) were used. Rainfall rates were simulated for the combination of direct rainfall (passive runoff) and for additional stormwater runoff from adjacent areas (active runoff). A typical pervious concrete block will allow water to pass through at flow rates greater than 0.2 cm/s and a typical extra fine sand will have a permeability of approximately 0.02 cm/s. The limit of the system with complete sand coverage resulted in an effective system permeability of approximately 0.004 cm/s which is similar to the rainfall intensity of a 30 min duration, 100-year frequency event in the southeastern United States. The results obtained are important in designing and evaluating pervious concrete as a paving surface within watershed management systems for controlling the quantity of runoff. PMID:16563606

Haselbach, Liv M; Valavala, Srinivas; Montes, Felipe

2006-10-01

143

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

PubMed

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

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

2009-02-01

144

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

NASA Technical Reports Server (NTRS)

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

Alshibli, Khalid A.; Sture, Stein

2000-01-01

145

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

USGS Publications Warehouse

Most sedimentary structures represented in sand bodies of the Rio Orinoco are tabular-planar cross-strata which, together with some wedge-planar cross-strata, are the products of sand-wave deposition. Locally, in areas of river meander where point bars characteristically form, trough structures forming festoon patterns are numerous. At a few localities, sets of nearly horizontal strata occur between tabular-planar sets and are interpreted to be the deposits of very fast currents of the upper flow regime; elsewhere, uncommon lenses and beds of silt, clay, or organic matter consisting of leaves and twigs, seem to be the result of quiet-water settling through gravity. By far the most common grain size represented in the tabular-planar and wedge-planar cross-strata of the sandwave deposits is medium sand (? - ? millimeter) as determined by screen analyses. Many samples, however, also contain moderate quantities of coarse or very coarse sand. Eolian dunes on top of the sand-wave deposits are dominantly fine grained. The river channel sands were determined to be largely moderately well sorted, although in some places they were mostly well sorted, and in others, mostly moderately sorted.

McKee, Edwin Dinwiddie

1989-01-01

146

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

PubMed

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

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

2013-01-01

147

Thermal Properties of oil sand  

NASA Astrophysics Data System (ADS)

Thermal recovery methods such as Cyclic Steam Injection or Steam Assisted Gravity Drainage (SAGD) are the effective methods for producing heavy oil or bitumen. In any thermal recovery methods, thermal properties (e.g., thermal conductivity, thermal diffusivity, and volumetric heat capacity) are closely related to the formation and expansion of steam chamber within a reservoir, which is key factors to control efficiency of thermal recovery. However, thermal properties of heavy oil or bitumen have not been well-studied despite their importance in thermal recovery methods. We measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of 43 oil sand samples from Athabasca, Canada, using a transient thermal property measurement instrument. Thermal conductivity of 43 oil sand samples varies from 0.74 W/mK to 1.57 W/mK with the mean thermal conductivity of 1.09 W/mK. The mean thermal diffusivity is 5.7×10-7 m2/s with the minimum value of 4.2×10-7 m2/s and the maximum value of 8.0×10-7 m2/s. Volumetric heat capacity varies from 1.5×106 J/m3K to 2.11×106 J/m3K with the mean volumetric heat capacity of 1.91×106 J/m3K. In addition, physical and chemical properties (e.g., bitumen content, electric resistivity, porosity, gamma ray and so on) of oil sand samples have been measured by geophysical logging and in the laboratory. We are now proceeding to investigate the relationship between thermal properties and physical/chemical properties of oil sand.

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

2013-12-01

148

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

USGS Publications Warehouse

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

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

2008-01-01

149

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

USGS Publications Warehouse

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

Robinson, Marci M.; McBride, Randolph A.

2008-01-01

150

Sand Sheet on Crater Floor  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

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

As with yesterday's image, this dune field is located inside a crater, in this case an unnamed crater at 26 degrees North latitude. In this VIS image the dunes are coalescing into a sand sheet, note the lack of dune forms to the north of the small hills. The presence of ridges and hills in the area is affecting the dune shapes.

Image information: VIS instrument. Latitude 26.4, Longitude 62.7 East (297.3 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2005-01-01

151

The Apollo 15 Coarse Fines  

E-print Network

I The Apollo 15 Coarse Fines (4-10 mm) Graham Ryder Sarah Bean Sherman Lunar and Planetary. TX 77058-4399 REFERENCE copy PLEASf 00 NOtr REbOIE #12;( The Apollo 15 Coarse Fines (4-10 mm) Graham. Johnson Space Center Houstqn, Texas JSC# 24035 #12;( THE APOLLO 15 COARSE FINES (4-10 mm) Introduction

Rathbun, Julie A.

152

Downward migration of metalaxyl fungicide in creeping bentgrass sand lysimeters as affected by organic waste, peat and zeolite amendments  

Microsoft Academic Search

Metalaxyl is a fungicide used for control of Pythium spp. diseases in turfgrass. The downward migration of metalaxyl was studied in irrigated lysimeters containing a fine sandy loam soil alone or sand amended with composted brewery waste, composted sewage sludge, peat or zeolite by analysis of the fungicide in leachates collected up to 65 days post application. The Arkport sandy

A. Martin Petrovic; William C. Barrett; Inga-Mai Larsson-Kovach; Charlotte M. Reid; Donald J. Lisk

1998-01-01

153

Recolonization of macrofauna in unpolluted sands placed in a polluted yachting harbour: A field approach using experimental trays  

Microsoft Academic Search

A field experiment using trays was conducted at Ceuta's yachting harbour, North Africa, to study the effect in recolonization of placing trays with unpolluted defaunate sediments (fine and gross sands with low contents of organic matter) inside an enclosed yachting harbour characterized by high percentages of silt and clay and high concentrations of organic matter. Sediment recolonization in the trays

J. M. Guerra-García; J. C. García-Gómez

2009-01-01

154

Tracing biogeochemical and microbial variability over a complete oil sand mining and recultivation process.  

PubMed

Recultivation of disturbed oil sand mining areas is an issue of increasing importance. Nevertheless only little is known about the fate of organic matter, cell abundances and microbial community structures during oil sand processing, tailings management and initial soil development on reclamation sites. Thus the focus of this work is on biogeochemical changes of mined oil sands through the entire process chain until its use as substratum for newly developing soils on reclamation sites. Therefore, oil sand, mature fine tailings (MFTs) from tailings ponds and drying cells and tailings sand covered with peat-mineral mix (PMM) as part of land reclamation were analyzed. The sample set was selected to address the question whether changes in the above-mentioned biogeochemical parameters can be related to oil sand processing or biological processes and how these changes influence microbial activities and soil development. GC-MS analyses of oil-derived biomarkers reveal that these compounds remain unaffected by oil sand processing and biological activity. In contrast, changes in polycyclic aromatic hydrocarbon (PAH) abundance and pattern can be observed along the process chain. Especially naphthalenes, phenanthrenes and chrysenes are altered or absent on reclamation sites. Furthermore, root-bearing horizons on reclamation sites exhibit cell abundances at least ten times higher (10(8) to 10(9)cellsg(-1)) than in oil sand and MFT samples (10(7)cellsg(-1)) and show a higher diversity in their microbial community structure. Nitrate in the pore water and roots derived from the PMM seem to be the most important stimulants for microbial growth. The combined data show that the observed compositional changes are mostly related to biological activity and the addition of exogenous organic components (PMM), whereas oil extraction, tailings dewatering and compaction do not have significant influences on the evaluated compounds. Microbial community composition remains relatively stable through the entire process chain. PMID:25201817

Noah, Mareike; Lappé, Michael; Schneider, Beate; Vieth-Hillebrand, Andrea; Wilkes, Heinz; Kallmeyer, Jens

2014-11-15

155

[Environmental toxicity of waste foundry sand].  

PubMed

The metal leaching characteristics and volatile organic compounds (VOCs) of five different types of waste foundry sands were analyzed with the toxicity characteristic leaching procedure (TCLP) and head space-gas chromatography (HS-GC). Microtox and soil dehydrogenase activity (DHA) tests were then used to evaluate the bio-effects of these waste sands. The results showed that due to the different metals poured and casting materials used to make the sand molds, there was significant difference among the five waste foundry sands in the compositions and concentrations of metal and organic pollutants. The concentrations of Fe in the leachates of iron and steel casting waste foundry sand exceeded the maximal allowable concentrations specified in the National Standard of Drinking Water Quality, whereas the As concentration in the leachate of aluminum casting waste foundry sand exceeded the standard. The five waste foundry sands had quite different compositions and levels of VOCs, which resulted in different levels of inhibition effects on the luminescent bacteria (30% and 95%). Additionally, the soil DHA tests suggested that metal pollutants in waste foundry sands may inhibit the soil microbial activity, whereas organics in the sands may slightly promote the microbial activity. The results of this study indicated that the waste foundry sands may pose considerable threat to the environment when improperly disposed. PMID:23745431

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

2013-03-01

156

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

NASA Astrophysics Data System (ADS)

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

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

157

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

158

Fine needle aspiration cytology.  

PubMed Central

Fine needle aspiration cytology is an inexpensive, atraumatic technique for the diagnosis of disease sites. This paper describes the technique and illustrates how it may be applied to the management of tumours throughout the body. The limitations of the method, the dangers of false positive reports, and the inevitability of false negative diagnoses are emphasised. In a clinical context the method has much to offer by saving patients from inappropriate operations and investigations and allowing surgeons to plan quickly and more rationally. It is an economically valuable technique and deserves greater recognition. Images PMID:2578481

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

1985-01-01

159

Marine gas hydrates in thin sand layers that soak up microbial methane  

Microsoft Academic Search

At Site U1325 (IODP Exp. 311, Cascadia margin), gas hydrates occupy 20–60% of pore space in thin sand layers (<5cm) surrounded by fine-grained intervals (2.5m thick on average) that contain little or no hydrate. This is a common occurrence in gas hydrate-bearing marine sequences, and it has been related to the inhibition of hydrate formation in the small pores of

Alberto Malinverno

2010-01-01

160

Production Mechanisms for the Sand on Titan and the Prospects for a Global Sand Sea  

NASA Astrophysics Data System (ADS)

With ~15% of its surface covered by sand seas, Titan turns out to be the Arrakis of the solar system. How the sand particles that make up the dunes are created, however, remains an outstanding question. Titan's haze particles are organic in composition as required by spectral analysis of dunes, however they have diameters of ~1um, and are 10,000,000 times too small by mass to directly represent the ~200-um sand particles. In addition to previous suggestions that sand could come from sintering of sand particles or by burial, lithification, and subsequent erosion (more like typical sands on Earth), we suggest two new mechanisms for production of sand in association with Titan's liquid reservoirs. Dissolution and reprecipitation as evaporite forms the gypsum dunes of White Sands, NM, USA on Earth, and could play a role on Titan as well. Alternatively, haze particles in the lakes and seas could aggregate into larger particles via flocculation, a mechanism seen to occur on Earth in Morocco. Each of these sand particle production ideas has associated predictions that can be tested by future observations. The lack of evident sand sources in VIMS data implies that Titan's sand seas may be old and their continuous interconnectedness across the Dark Equatorial Belt implies that all of the equatorial dunefields may represent a single compositionally uniform sand sea. We will present possibilities for sands from this sea to bridge the large gap across Xanadu, including barchan chains and fluvial transport.

Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; MacKenzie, Shannon

2014-11-01

161

Fine Channel Networks  

NASA Technical Reports Server (NTRS)

A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

1997-01-01

162

Volumetric sand production model and experiment  

NASA Astrophysics Data System (ADS)

A sand production model was developed for volumetric sand production predictions that take into account the effects of the external stresses and fluid flow rate. The model couples the poro-mechanical behaviour of the solid-fluid system with the erosion behaviour of the solids due to fluid flow. It predicts reasonably experimental volumetric sand production data from a hollow cylinder test on a weak sandstone. The test results show that in weak and compactive sandstones, sand production is associated with decohesioning and plasticification of a zone around the inner hole which can then be mobilized by the hydrodynamic forces of the fluid flow. The sand production rate increases both with external applied stress and fluid flow rate but it is constant with time under constant external stress and fluid flow rate. In both cases a critical lower limit has to be exceeded for sand production initiation.

Papamichos, E.; Vardoulakis, I.; Tronvoll, J.; Skjærstein, A.

2001-07-01

163

Liquefaction of sand under low confining pressure  

NASA Astrophysics Data System (ADS)

Undrained behaviour of sand under low cell pressure was studied in static and cyclic triaxial tests. It was found that very loose sand liquefies under static loading with the relative density being a key parameter for the undrained behaviour of sand. In cyclic triaxial tests, pore water pressures built up during the cyclic loading and exceeded the confining cell pressure. this process was accompanied by a large sudden increase in axial deformation. The necessary number of cycles to obtain liquefaction was related to the confining cell pressure, the amplitude of cyclic loading and the relative density of sand. In addition, the patterns of pore water pressure response are different from those of sand samples with different relative densities. The test results are very useful for expounding scour mechanism around coastal structures since they relate to the low stress behaviour of the sand.

Shaoli, Yang; Sandven, Rolf; Grande, Lars

2003-10-01

164

Luminescence dating of mojave desert sands  

NASA Astrophysics Data System (ADS)

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

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

165

Onsite Wastewater Treatment Systems: Sand Filters  

E-print Network

the incoming wastewater; ? Chemical sorption, in which contaminants stick to the surface of the sand and to the biological growth on the sand surface; and ? Assimilation, in which aerobic microbes eat the nutrients in the wastewater. The success of treat...- ing wastewater depends on these microbes. Air must be available for these microbes to live. Sand filters are often partially or completely buried in the ground, but may be built above ground where there is a high water table or bedrock...

Lesikar, Bruce J.

2008-10-23

166

Marine Gas Hydrates in Thin Sands From in Situ Biogenic Methane  

NASA Astrophysics Data System (ADS)

Methane in marine gas hydrate deposits is generated either (1) within the gas hydrate stability zone (GHSZ) by in situ biogenic processes or (2) below the GHSZ and transported upward by fluid advection. This work examines whether in situ methane generation can explain hydrate occurrences within sand layers of mud- dominated continental margin sequences. For example, at IODP Site U1325 (Exp. 311, Cascadia margin), gas hydrate occupies 30-60% of the pore space in thin sand layers (~5 cm thick), with no clear evidence of hydrate in the adjacent marine mud intervals (2.5 m thick on average). This work models the formation of gas hydrates in marine sediments and accounts for in situ generation and diffusion of methane. Under free-space conditions, hydrates form when the dissolved methane concentration exceeds the methane solubility for bulk water. In porous media, however, theory and experiments show that gas hydrate formation is inhibited in small pores. Thus, methane concentration may exceed the free-space solubility in fine-grained marine muds, whereas in sand layers the pores are large enough for gas hydrate to form as in free-space conditions. To model the effect of pore size, consider a 2.5 m thick mud layer sandwiched between two sand layers. Methane concentration at the top and bottom of the mud layer (in the thin sands) is fixed to free-space solubility. As these sediments are buried, in situ biogenic activity increases their methane concentration. Once concentration in the mud layer exceeds free-space solubility, methane will be transported by diffusion into the upper/lower bounding sand layers. The rate of diffusion is fast compared to the rate of biogenic methane generation, and therefore the maximum methane concentration in excess of free-space solubility within the mud layer will always remain very small (<1% of solubility). Even a minor inhibition of gas hydrate formation in fine-grained mud will cause any in situ biogenic methane to be transported into the adjacent sands, where it forms hydrate. As a consequence, the inhibition of gas hydrate formation in marine mud and the diffusive transport of methane into thin sands can result in large concentrations of hydrate (~50% of pore volume) in thin sand layers even though in situ biogenic methane would produce only small amounts of hydrate (~1% of pore volume) if it formed in the mud layers.

Malinverno, A.

2008-12-01

167

Fine particulate capture device  

NASA Technical Reports Server (NTRS)

To capture fine particulate matter in a gas such as air, a dielectric fluid is directed to the center of whichever face of a rotating disc is exposed to the air flow. The disc is comprised of two or more segments which bear opposite electrostatic potentials. As the dielectric fluid is centrifuged towards the periphery of the rotating disc, the fluid becomes charged to the same potential as the segment over which it is passing. Particulate matter is attracted to the charged segment and is captured by the fluid. The fluid then carries the captured particulate matter to a collection device such as a toroidal container disposed around the periphery of the disc. A grounded electrically-conductive ring may be disposed at the outer periphery of the disc to neutralize the captured particles and the fluid before they enter the container.

Peterson, V. S.; Siewert, R. D. (inventors)

1979-01-01

168

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

NASA Astrophysics Data System (ADS)

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

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

169

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

170

Invasive plants on disturbed Korean sand dunes  

Microsoft Academic Search

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

Kee Dae Kim

2005-01-01

171

Liquefaction in Subsurface Layer of Sand  

USGS Multimedia Gallery

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

2009-01-26

172

Explorations with the Sand and Water Table.  

ERIC Educational Resources Information Center

Presents sand and water activities for young children as examples of sensory explorations, science activities, and comforting play. Includes information on health and safety precautions, adaptations for children with physical disabilities, the use of other materials, and sand and water toys made from one-liter plastic bottles. (KB)

Texas Child Care, 2001

2001-01-01

173

NEW DEVELOPMENTS IN SLOW SAND FILTRATION  

EPA Science Inventory

Recent regulations promulgated by the U.S. Environmental Protection Agency (EPA), including the Surface Water Treatment Rule, have helped to renew the interest in the use of slow sand filtration (SSF) for treating surface waters for small communities. low sand filtration is not a...

174

DRINKING WATER TREATMENT USING SLOW SAND FILTRATION  

EPA Science Inventory

Recent re-interest in slow sand filtration was brought about by the needs for small communities to install treatment technologies that are effective, less costly, and easier to operate and maintain than the more sophisticated rapid sand filters. These simpler technologies for sma...

175

White Sands, Carrizozo Lava Beds, NM  

NASA Technical Reports Server (NTRS)

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

1973-01-01

176

Sand reinforced with shredded waste tires  

SciTech Connect

The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce sand. Direct shear tests were conducted on mixtures of dry sand and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, sand matrix unit weight, shred content, shred length, and shred orientation. From results of the tests, three significant factors affecting shear strength were identified: normal stress, shred content, and sand matrix unit weight. A model for estimating the strength of reinforced soils was also evaluated to determine its applicability to mixtures of sand and tire shreds. When the model is calibrated using results from one shred content, it may be useful for estimating the friction angle for other shred contents. In all cases, adding shredded tires increased the shear strength of sand, with an apparent friction angle ({phi}{prime}) as large as 67{degree} being obtained. Shred content and sand matrix unit weight were the most significant characteristics of the mixes influencing shear strength. Increasing either of these variables resulted in an increase in {phi}{prime}. Tests were also conducted on specimens consisting of only shredded tires (no sand), and the friction angle obtained was 30{degree}.

Foose, G.J.; Benson, C.H.; Bosscher, P.J. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering] [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering

1996-09-01

177

Western gas sands: Technology status report  

Microsoft Academic Search

Western gas sands research is conducted by the US Department of Energy's (DOE's) Morgantown Energy Technology Center to encourage the development of very low permeability, lenticular gas sands in the western US. This research is an integral part of DOE's Unconventional Gas Recovery Program, which is a multidisciplinary effort to develop the technology for producing natural gas from resources that

K. H. Frohne; C. A. Komar

1989-01-01

178

Photoacoustic infrared spectroscopy of Syncrude post-extraction oil sand.  

PubMed

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

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

2006-06-01

179

Ottawa Sand for Mechanics of Granular Materials (MGM) Experiment  

NASA Technical Reports Server (NTRS)

What appear to be boulders fresh from a tumble down a mountain are really grains of Ottawa sand, a standard material used in civil engineering tests and also used in the Mechanics of Granular Materials (MGM) experiment. The craggy surface shows how sand grans have faces that can cause friction as they roll and slide against each other, or even causing sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM uses the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. These images are from an Electron Spectroscopy for Chemical Analysis (ESCA) study conducted by Dr. Binayak Panda of IITRI for Marshall Space Flight Center (MSFC). (Credit: NASA/MSFC)

2000-01-01

180

Hematite Outlier and Sand Dunes  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 4 December 2003

This image shows a crater just south of the edge of the famous hematite-bearing surface, which is visible in the context image as a smooth area to the north. The crater has two features of immediate note. The first is a layered mound in the north part of the crater floor. This mound contains hematite, and it is an outlying remnant of the greater deposits to the north that have otherwise completely disappeared in this crater. The second feature is a dune field in the center of the crater floor, with dark dunes indicating winds from the northwest. The dunes grade into a dark sand sheet with no coherent structure, indicating that the sand layer thins out to the south and east.

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

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

181

Ecological release in White Sands lizards  

PubMed Central

Ecological opportunity is any change that allows populations to escape selection from competition and predation. After encountering ecological opportunity, populations may experience ecological release: enlarged population size, broadened resource use, and/or increased morphological variation. We identified ecological opportunity and tested for ecological release in three lizard colonists of White Sands, New Mexico (Sceloporus undulatus, Holbrookia maculata, and Aspidoscelis inornata). First, we provide evidence for ecological opportunity by demonstrating reduced species richness and abundance of potential competitors and predators at White Sands relative to nearby dark soils habitats. Second, we characterize ecological release at White Sands by demonstrating density compensation in the three White Sands lizard species and expanded resource use in White Sands S. undulatus. Contrary to predictions from ecological release models, we observed directional trait change but not increased trait variation in S. undulatus. Our results suggest that ecological opportunity and ecological release can be identified in natural populations, especially those that have recently colonized isolated ecosystems. PMID:22393523

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

2011-01-01

182

Geomorphic controls on fine sediment reinfiltration into salmonid spawning gravels and the implications for spawning habitat rehabilitation  

NASA Astrophysics Data System (ADS)

Anthropogenic activities often increase the flux of fine sediment to fluvial environments. In gravel-bed streams the extent to which augmented fines loading causes the degradation of vital interstitial habitats is determined by factors controlling fines infiltration into channel substratum. Previous research suggests that substrate pore constriction size, intensity of upwelling interstitial flow, and the quantity of fines transported across the bed surface (i.e., exposure dose) are three important factors controlling substrate fines content. Few field studies have investigated the interactive effects of these physical factors. We constructed 17 experimental redds in brook trout spawning microhabitats in a boreal forest stream in Quebec, Canada, to investigate the role of pore constriction size, hyporheic flow, and exposure dose on substrate fines content. To simulate the effect of spawning in coarsening the substrates, redds were partially cleaned of coarse sand and of all fine sediment (< 0.5 mm). Results show that coarse sands and fine gravel (0.5-4 mm; filter class) acted as a filter of percolating fine sediment (< 0.5 mm). We found that this filtering effect (i.e., lower fines density at egg pocket depth) occurred at sites where the proportion of the filter class in the substratum above egg pocket depth exceeded a threshold value of 18%, as indicated by a statistically significant step-function response between fines gradient with depth and the filter class content in the uppermost layers of the bed. Results also indicated that fines content at depth was unrelated to fines exposure. Estimated upward seepage rates were well below the threshold velocity that would inhibit the percolation of medium-grained sand (i.e., 0.5 mm) into the bed. These results suggest that within these gravel-bed spawning substrates the abundance of filter classes was the primary determinant of fines content at depth. This study highlights the importance of considering filter class content in the implementation of spawning habitat rehabilitation schemes and when assessing the susceptibility of incubation microhabitats to augmented fine sediment loading to streams.

Franssen, Jan; Lapointe, Michel; Magnan, Pierre

2014-04-01

183

Compositional Variations of Rocknest Sand, Gale Crater, Mars  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

184

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

PubMed

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

Rytter, Rose-Marie

2013-09-01

185

Invasive plants on disturbed Korean sand dunes  

NASA Astrophysics Data System (ADS)

The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic soils, and conservation of surrounding sand dune areas.

Kim, Kee Dae

2005-01-01

186

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

PubMed Central

Background Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear. Methods In 2007, visitors at two recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days later, participants answered questions about health symptoms since the visit. F+ coliphage, Enterococcus, Bacteroidales, fecal Bacteroides, and Clostridium spp. in wet sand were measured using culture and molecular methods. Results We analyzed 144 wet sand samples and completed 4,999 interviews. Adjusted odds ratios (aORs) were computed, comparing those in the highest tertile of fecal indicator exposure with those who reported no sand contact. Among those digging in sand compared with those not digging in sand, a molecular measure of Enterococcus spp. (calibrator cell equivalents/g) in sand was positively associated with gastrointestinal (GI) illness (aOR = 2.0 [95% confidence interval (CI) = 1.2–3.2]) and diarrhea (2.4 [1.4–4.2]). Among those buried in sand, point estimates were greater for GI illness (3.3 [1.3–7.9]) and diarrhea (4.9 [1.8–13]). Positive associations were also observed for culture-based Enterococcus (colony-forming units/g) with GI illness (aOR digging = 1.7 [1.1–2.7]) and diarrhea (2.1 [1.3–3.4]). Associations were not found among non-swimmers with sand exposure. Conclusions We observed a positive relationship between sand contact activities and enteric illness as a function of concentrations of fecal microbial pollution in beach sand. PMID:22157306

Heaney, Christopher D.; Sams, Elizabeth; Dufour, Alfred P.; Brenner, Kristen P.; Haugland, Richard A.; Chern, Eunice; Wing, Steve; Marshall, Stephen; Love, David C.; Serre, Marc; Noble, Rachel; Wade, Timothy J.

2011-01-01

187

Developments in tar sands in 1981  

SciTech Connect

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

Wennekers, J.H.N.

1982-11-01

188

On anthropic principles fine tuning and chaos  

Microsoft Academic Search

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

Zsolt Hetesi; L. Végh

2006-01-01

189

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

190

Electrostatic force on saltating sand  

NASA Astrophysics Data System (ADS)

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

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

1998-04-01

191

Uprated fine guidance sensor study  

NASA Technical Reports Server (NTRS)

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

1984-01-01

192

The effect of fines upon the compaction characteristics of a well graded sand  

E-print Network

) of the oompactive effort used. Influence of t1oisture Content Proctor showed by laboratory tests that the moisture content of a soil sample may bs varied to give maximum density for a given compaotivs 1 effort. This phenomenon may be explained in the I...) of the oompactive effort used. Influence of t1oisture Content Proctor showed by laboratory tests that the moisture content of a soil sample may bs varied to give maximum density for a given compaotivs 1 effort. This phenomenon may be explained in the I...

Long, Robert Eugene

2012-06-07

193

Provenance and glacial history of very fine quartz sand from the Weddell Sea, Antarctica  

E-print Network

Ice Sheet (WAIS). As the initiation and growth of these ice sheets had different histories, documenting the contribution of sediment from each ice sheet through time would allow evaluation of temporal changes in the ice sheets. The final objective... Ice Sheet (WAIS). As the initiation and growth of these ice sheets had different histories, documenting the contribution of sediment from each ice sheet through time would allow evaluation of temporal changes in the ice sheets. The final objective...

Smith, Caryn Hallett

2012-06-07

194

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

NASA Astrophysics Data System (ADS)

The Quaternary deposits on the Tersk coast of the White Sea are represented by marine deposits (the Tersk sands) enriched in the sea-sorted eluvium of the red Tersk sandstone. These deposits and the soils developed from them are characterized by the predominance of the fine sand fraction and the absence of gravel and the coarser fractions. The sediments derived from the red Tersk sandstone have an impoverished chemical composition (the silica content reaches 75-80%). The iron-illuvial podzols developed from them are characterized by the slightly pronounced differentiation of the main oxides and by the eluvial-illuvial redistribution of the amorphous Al and Fe compounds. Sandy soils—psammozems—with undifferentiated soil profiles are developed from windblown sands subjected to afforestation and from coastal marine sands under a relatively thin natural plant cover. Iron-illuvial podzols buried under a thin sand layer preserve the Al-Fe-humus type of the profile differentiation. In the recently deposited sand layer, the eluvial-illuvial redistribution of the chemical elements is absent.

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

2011-01-01

195

Unequal Mobility of Gravel and Sand in Weakly Bimodal River Sediments  

NASA Astrophysics Data System (ADS)

Bed load was trapped during flood events over a 20-month period at the lower end of the Allt Dubhaig, a small river in Scotland with rapid downstream fining of gravel bed material on a slowly aggrading concave long profile. The channel bed near the trap is predominantly gravel with a secondary sand mode. Total transport in each event depended mainly on peak shear stress, rather than duration over a threshold. Bed load was mainly sand in smaller events, bimodal in intermediate events, and mainly gravel in the biggest floods. Mean and maximum grain diameter both increased with peak shear stress, but in different ways. Analysis of fractional transport rates and maximum grain size in relation to peak shear stress suggests that gravel transport is slightly size selective but sand transport is close to equal mobility. The slight selectivity in gravel transport is consistent with previous field studies of near-equilibrium unimodal beds and supports assumptions made in the numerical model of Hoey and Ferguson (1994), which successfully simulates the observed amount of downstream fining over the 2.5-km upstream of the bed load trap.

Wathen, Simon J.; Ferguson, Robert I.; Hoey, Trevor B.; Werritty, Alan

1995-08-01

196

Dynamics of the Barents-Kara ice sheet as revealed by quartz sand grain microtextures of the late Pleistocene Arctic Ocean sediments  

NASA Astrophysics Data System (ADS)

During the entire Quaternary, ice sheets advanced and retreated across the circum-Arctic margins in a series of climate related glacial-interglacial cycles. It is critical to obtain evaluation of the nature of initiated glaciers at the Arctic margins after the pronounced interglacial periods. In this study this will be done by inferring from glacially generated quartz sand grain surface microtextures and related sedimentology extracted from the central Arctic Ocean sediments. These microtextures can be correlated with the generation and fluctuations in the extent of the late Pleistocene Eurasian Ice Sheet i.e. Barents-Kara Ice Sheet. The central Arctic Ocean sediments in the Lomonosov Ridge, having been deposited after the late Pleistocene interglaciations and having had no internal hiatuses, provide an excellent time window for usage of quartz sand grain surface textures for evaluating possible evolving glaciers and continental ice sheets. This is based on the fact that iceberg and sea-ice transported quartz sand grains and their mechanically formed surface textures, created under high cryostatic stress, are diagnostic for glacier thickness and dynamics having been existed in sediment source areas. Sand-sized quartz grains in deep marine sediments favour iceberg or sea-ice transportation with characteristic content of microtextures formed prior this transportation. The sand grain surface microtextures and their frequencies of the selected submarine Lomonosov Ridge sediments during Marine Isotope Stage (MIS) 5 to MIS 3 are analysed using a scanning electron microscope (SEM). Coring during the Arctic Ocean 96 expedition (core 96/12-1pc) provided alternating clay to silty clay sediments which are characterised by prominent silt to sand-size containing intervals. The specific glacial crushing and high cryostatic stress generated features, such as high angularity, conchoidal fractures, steps and sub-parallel linear fractures, were observed from quartz sand grain surfaces. Continental ice generation and extent are evident soon after the Eemian interglaciation and the following MIS 4 stage shows the highest frequencies of glacigenic microtextures. The microtexture generation under high cryostatic pressure underneath ice more than 1 km thick, can be taken as concurrent signal of the temporal expansion of the northernmost continental ice sheets, which could easily have reached the shelf break of the Barents, Kara and western Laptev seas during that time.

Strand, Kari; Immonen, Ninna

2010-12-01

197

Petrophysical Analysis of Oil Sand in Athabasca  

NASA Astrophysics Data System (ADS)

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

cheong, S.; Lee, H.

2013-12-01

198

Sand consolidation methods using adsorbable catalysts  

SciTech Connect

Methods are provided for selectively consolidating sand grains within a subterranean formation. First an acidic zirconium salt catalyst, such as ZrOCl/sub 2/, Zr(SO/sub 4/)/sub 2/, or ZrCl/sub 4/, is injected into the subterranean formation, wherein the acidic salt catalyst is adsorbed to the surface of the sand grains. Next a polymerizable resin composition such as furfuryl alcohol oligomer is introduced into the well formation. Polymerization of the resin occurs upon exposure to the elevated well temperatures and contact with the acid salt catalyst adsorbed to the sand grains. The polymerized resin serves to consolidate the surfaces of the sand grains while retaining permeability through the pore spaces. An ester of a weak organic acid is included with the resin compositions to control the extent of a polymerization by consuming the water by-product formed during the polymerization reaction.

Friedman, R. H.

1985-04-23

199

Generation of sand bars under surface waves  

E-print Network

(cont.) Experiments were performed in a large wave flume to validate the theory and to study additional aspects of sand bar evolution. The wave envelope and bar profile were recorded for low and high beach reflection, ...

Hancock, Matthew James, 1975-

2005-01-01

200

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

Microsoft Academic Search

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

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

2003-01-01

201

Sand Beach Bacteria: Enumeration and Characterization  

PubMed Central

Bacteria in the water-saturated sand of a relatively unpolluted sand beach were enumerated by direct microscope and viable counting. The number of interstitial bacteria was estimated to be a significant fraction of the total number of bacteria present. Three hundred sixty-two strains were isolated and submitted to cultural and biochemical tests. Fermentational abilities and the production of indole suggested that a significant number of these bacteria were symbiotically associated with resident metazoans. PMID:4356458

Khiyama, H. M.; Makemson, J. C.

1973-01-01

202

Hydrothermal deformation of granular quartz sand  

Microsoft Academic Search

Isotropic and triaxial compression experiments were performed on porous aggregates of St Peter quartz sand to explore the influence of temperature (to 225°C). During isotropic stressing, samples loaded at elevated temperature exhibit the same sigmoidal stress-strain curves and non-linear acoustic emission rates as have previously been observed from room temperature studies on sands, sandstones, and soils. However, results from our

Stephen L. Karner; Andreas K. Kronenberg; Frederick M. Chester; Judith S. Chester; Andrew Hajash Jr

2008-01-01

203

Developing Alberta's oil sands, 1920--2002  

NASA Astrophysics Data System (ADS)

This dissertation examines the origins and development of the Alberta oil sands industry over the last century from a scientific project to a commercial endeavor. Based on extensive use of primary sources, the manuscript integrates the developments in a number of fields (politics, international relations, business and economics, and changing oil-recovery technology) that have made it possible to "manufacture" oil from the Alberta tar sands at less than $10 U.S. per barrel.

Chastko, Paul Anthony

204

Numerical modeling of basaltic sand ripples on Eagle crater as indirect evidence for the hysteresis effect in Martian saltation  

NASA Astrophysics Data System (ADS)

Aeolian ripples, which form regular patterns on sand beaches and desert floors and also on Mars, indicate the instability of flat sand surfaces under the wind-induced transport of sand grains. The opportunity rover documented small normal basaltic sand ripples at the bottom of Eagle crater in Meridinai planum. These ripples are composed of fine basaltic sand (100 micron) and their average wavelength and height are 10 cm and 1 cm respectively. Such light particles are thought to be easily suspended by turbulence at the fluid threshold, such that the wind speed at which these bedforms developed must be substantially below the fluid threshold. The occurrence of these bedforms on the Martian surface thus requires the impact threshold to be substantially smaller than the fluid threshold. Recently, it was suggested that saltation on Mars can be maintained at much lower wind speeds than the fluid threshold which is needed to initiate it (Kok, 2010). We used simulations of the steady state saltation model COMSALT together with a dynamic model for sand ripples (Yizhaq et al., 2004) to show that the small basaltic ripples can develop under wind speeds below the threshold for suspension. We used COMSALT to give the basic values of the parameters that used by the ripple model for saltation on Mars with and without cohesion: 1. The average number of reptating grains per impact of one saltating grain. 2. The number density of impact saltating grains on flat surface. 3. The probability distribution of reptation lengths. We used COMSALT results to calculate the sand flux on Mars for different shear velocities and used GCM models simulations for prediction of the sand flux under predicted wind regime and compare it with recent estimations (Bridges et al., 2012). Our numerical simulations (Fig. 1) show that ripples like the basaltic ripples on Eagle crater can be developed by shear velocity much below the fluid threshold by the impact mechanism. These findings can be regarded as an indirect proof of the unique saltation mechanism on Mars. References Bridges, N. T. et al. 2012. Earth-like sand fluxes on Mars. Nature 485, 339-342. Kok, J. F. 2010. Differences in the wind speeds required for initiation versus continuation of sand transport on Mars: Implications for dunes and sand storms. Physical Review Letters, 104, 074502. Yizhaq, H., Balmforth, N.J and Provenzale, A. 2004. Blown by wind: Nonlinear dynamics of aeolian sand ripples. Physica D, 195, 207-228. Model simulation of normal ripples on Mars with parameters computed by COMSALT for different shear velocities with and without cohesion after one hour. The inset shows the final ripples profile for u*=0.65 m/s.

Yizhaq, H.; Kok, J. F.; Michaels, T. I.

2012-12-01

205

WITSEG sampler: a segmented sand sampler for wind tunnel test  

Microsoft Academic Search

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

Zhibao Dong; Hongyi Sun; Aiguo Zhao

2004-01-01

206

2D Mesoscale Simulations of Projectile Penetration into Sand  

Microsoft Academic Search

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

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

2007-01-01

207

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

208

Studies on use of Copper Slag as Replacement Material for River Sand in Building Constructions  

NASA Astrophysics Data System (ADS)

This work focuses on the use of copper slag, as a partial replacement of sand for use in cement concrete and building construction. Cement mortar mixtures prepared with fine aggregate made up of different proportions of copper slag and sand were tested for use as masonry mortars and plastering. Three masonry wall panels of dimensions 1 × 1 m were plastered. The studies showed that although copper slag based mortar is suitable for plastering, with the increase in copper slag content, the wastage due to material rebounding from the plastered surfaces increases. It is therefore suggested that the copper slag can be used for plastering of floorings and horizontal up to 50 % by mass of the fine aggregate, and for vertical surfaces, such as, brick/block walls it can be used up to 25 %. In this study on concrete mixtures were prepared with two water cement ratios and different proportions of copper slag ranging from 0 % (for the control mix) to 100 % of fine aggregate. The Concrete mixes were evaluated for workability, density, and compressive strength.

Madheswaran, C. K.; Ambily, P. S.; Dattatreya, J. K.; Rajamane, N. P.

2014-09-01

209

Perch population assessment in lakes reclaimed using oil-sands derived material  

SciTech Connect

The mining and extraction of petroleum products from oil-sands involves large areas of land and produces enormous volumes of tailings. One possible land reclamation option is to incorporate fine-tailings material into the bottoms of constructed lakes capped with natural surface water. The wet landscape method represents potential risk to aquatic biota-naphthenic acids and PAHs elute from pore water contained in the fine-tailings substrate. In spring 1995 yellow perch were stocked into a large-scale (5ha) experimental pond that consisted of fine-tailings capped with natural water as well as into two other reclaimed ponds that were constructed with oil-sands overburden material. Prior to stocking of perch, ponds had colonized with cyprinids, macrophytes and benthic invertebrates over a two year period. Perch were sampled in fall 1995 for age, condition factor, liver size, gonad size, fecundity, stomach contents, liver mixed-function oxygenase activity (MFO), bile PAH metabolites and plasma steroid hormones. When compared to the source lake, perch in the DP did not show reduced reproductive potential. Perch in all of the reclaimed ponds demonstrated exposure to organic compounds as indicated by marginally induced MFO activity and increased liver size. Exposure to naphthenates and PAHs in water as well as ecological environmental factors will be discussed.

Heuvel, M.R. van den; Dixon, D.G. [Univ. of Waterloo, Ontario (Canada); Power, M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada); Boerger, H.; MacKinnon, M.D.; Meer, T. van [Syncrude Canada, Fort McMurray, Alberta (Canada)

1995-12-31

210

Offbank transport of carbonate sands in northern Straits of Florida - a function of sea level  

SciTech Connect

The southwest Florida continental slope, bordering the northern Straits of Florida, consists of a thick accumulation of carbonate sediments. High-resolution seismic data show oblique prograding clinoforms oriented offbank indicating large amounts of shelf-derived material are being transported off the shelf and deposited on the slope. No evidence of mass wasting was found, suggesting deposition occurred by a continuous influx from the adjacent shelf. Sediment cores show an upward gradation from medium to coarse carbonate sands and granules to fine muds. The sand and granule fraction, dominated by coralline algae, mollusks, and benthic foraminifera, is typical of sediments found on the adjacent shelf. The fine fraction, however, is a foram or pteropod ooze containing only minor amounts of shelf-derived material. The fining-upward sequence indicated the greatest input of shelf material occurred during lowered sea level. During these periods, large quantities of shelf sediments were funneled through breaks in the shallow banks to the north and deposited on the slope. As sea level continued to rise, less shelf sediment was transported offbank. Under current conditions of high sea level, very little shelf material is being contributed to the slope. The slope therefore acts as a sink during sea level lowstands, for shelf-derived carbonate material produced during sea level highstands. The existence of at least 5 such sequences implies a cyclicity of similar depositional episodes that may be correlated with sea level fluctuations.

Brooks, G.R.; Holmes, C.W.

1985-02-01

211

Provenance and recycling of Arabian desert sand  

NASA Astrophysics Data System (ADS)

This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al-Batin fossil alluvial fan or even from Mesozoic sandstones of the Arabian margin accreted to the Cenozoic Zagros orogen. Due to extensive recycling and the fact that zircon is so resistant to weathering and erosion, the U-Pb age signatures are much less powerful a tracer of sedimentary provenance than framework petrography and heavy minerals. Actualistic provenance studies of dune fields at subcontinental scale shed light on the generation and homogenization of aeolian sand, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.

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

2013-05-01

212

Provenance and recycling of Arabian desert sand  

NASA Astrophysics Data System (ADS)

This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al-Batin fossil alluvial fan or even from Mesozoic sandstones of the Arabian margin accreted to the Cenozoic Zagros orogen. Due to extensive recycling and the fact that zircon is so resistant to weathering and erosion, the U-Pb age signatures are much less powerful a tracer of sedimentary provenance than framework petrography and heavy minerals. Actualistic provenance studies of dune fields at subcontinental scale shed light on the generation and homogenization of aeolian sand, and allow us to trace complex pathways of multistep sediment transport, thus providing crucial independent information for accurate palaeogeographic and palaeoclimatic reconstructions.

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

2013-04-01

213

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

Microsoft Academic Search

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

Brian R. Turner; Denys B. Smith

1997-01-01

214

Geological controls on porosity and permeability in reservoir sands, Goodwyn field, Rankin Trend, northern Barrow-Dampier subbasin, northwest Shelf, Australia  

SciTech Connect

Goodwyn field is a major gas and condensate field with reserves of 4.1 tcf of gas and 254 million bbl of condensate and a 31-m oil rim in the southern part of the field. The field is a large tilted fault block open to the north and bounded by major faults to the south, west, and southeast. There are no significant internal faults within the field. The hydrocarbon-bearing reservoirs dip gently northwards at 5-6[degrees] and are truncated by the Main unconformity. Progressively younger units subcrop northward beneath the Main unconformity. Cretaceous deep-water marine sediments directly above the Main unconformity form the seal to the field. Core from the GE unit (main reservoir sand) defines two lithofacies: a medium to coarse-grained subarkosic unit (facies 1) and a fine to medium-grained subarkosic unit (facies 2). Both facies were laid down as channeled-braid plain to coarse-grained meander-belt sands. The overlying GD unit core defines a third sand lithofacies (facies 3): a fine to medium-grained sand characterized by abundant siderite. Although modified by a diagenetic overprint of quartz over-growths and kaolin cements, reservoir quality in the GE reservoir sands was established at the time of the deposition. Porosity pathways within facies 1 and 2 have acted as preferential conduits for ongoing fluid flow. In contrast, the finer grained and especially more clay-rich marine-associated GD sands (facies 3) have had their permeability reduced by the precipitation of authigenic quartz, kaolin, and siderite cements. Within the GE reservoir, zones with highest porosity are not a reliable indicator of the best of many excellent permeability sands. The most porous reservoir sands in the GE unit are not necessarily the most permeable. The coarser grained sands have wireline-derived porosities in the range 19-23%, yet they are better reservoirs than fine to medium-grained sands with porosities up to 26%. This is due to the relatively larger pores in the facies 1 sands.

Warren, J.K. (Curtin Univ., Perth, Western Australia (Australia)); Tingate, P.; Tarabbia, P. (NCPGG/APCRC-Thebarton Campus, Adelaide, South Australia (Australia))

1993-09-01

215

Quantitative Measurements of Bedform Transport Rates and Sand Sheet Character in the Lower Mississippi River  

NASA Astrophysics Data System (ADS)

Channel sand volume and downstream flux in the Mississippi River have important implications for proposed mitigation projects (dredging and pipelines) that seek to utilize this resource for replenishing neighboring barrier islands and restoring Louisiana's deteriorating wetlands. This study quantifies bedform migration-induced sand flux through the lower river on daily and seasonal timescales, and evaluates the sedimentary character of the bedload component. Observations and measurements were conducted along three study grids (Audubon Park, English Turn and Venice) over a range of river discharges between April 2003 and January 2005. Two multibeam bathymetric profiles of the study grids were conducted 24 h apart to document bedform migration, and stratigraphy and thickness of the sand layer were confirmed by CHIRP seismic profiling. Downstream transport is evaluated from bed elevation changes for a 1 m grid after correcting for river stage, and utilized to calculate bedload sand fluxes for larger, averaged grid cells after visual examination confirmed dunes had migrated <1 wavelength. Algorithms were formulated to remove spurious grid cells created by vessel motion, navigation and swath-matching errors. Initial data analysis indicates flux rates conform to expected trends: values are proportional to river discharge and are higher in the channel thalweg of straight reaches relative to shallower water. Bedform size also increases with river discharge and spatial changes in flux rates; height ranges from <1 m to 10 m, and wavelength from 10 m to 100 m. Seasonal trends in sand sheet thickness are evident, particularly in deeper meander reaches, where aggradation occurs at low flow and scour is observed during high flow. At highest discharges observed (35,000 m3/sec), bedform troughs bottom out on exposed relict fluvio-deltaic strata that the river has incised (i.e., sediment starved). A spatially uniform grab sampling effort (250 samples) provided grain size data of the active sand sheet for the lower 135 km of the river. A downstream trend of decreasing grain size (2.6 to 2.0 ?) is likely due to the finest sand fraction leaving suspension and becoming bedload as river gradient and velocity progressively decrease. Locally, grain size increases in the deepest portions of the channel as a result of enhanced flow scouring the fine and medium sand fraction.

Nittrouer, J. A.; Allison, M. A.; Campanella, R.

2005-05-01

216

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

217

Spearfish water sand: an overlooked play  

SciTech Connect

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

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

1983-08-01

218

Capturing phosphates with iron enhanced sand filtration.  

PubMed

Most treatment practices for urban runoff capture pollutants such as phosphorus by either settling or filtration while dissolved phosphorus, typically as phosphates, is untreated. Dissolved phosphorus, however, represents an average 45% of total phosphorus in stormwater runoff and can be more than 95%. In this study, a new stormwater treatment technology to capture phosphate, called the Minnesota Filter, is introduced. The filter comprises iron filings mixed with sand and is tested for phosphate removal from synthetic stormwater. Results indicate that sand mixed with 5% iron filings captures an average of 88% phosphate for at least 200 m of treated depth, which is significantly greater than a sand filter without iron filings. Neither incorporation of iron filings into a sand filter nor capture of phosphates onto iron filings in column experiments had a significant effect on the hydraulic conductivity of the filter at mixtures of 5% or less iron by weight. Field applications with up to 10.7% iron were operated over 1 year without detrimental effects upon hydraulic conductivity. A model is applied and fit to column studies to predict the field performance of iron-enhanced sand filters. The model predictions are verified through the predicted performance of the filters in removing phosphates in field applications. Practical applications of the technology, both existing and proposed, are presented so stormwater managers can begin implementation. PMID:22482494

Erickson, Andrew J; Gulliver, John S; Weiss, Peter T

2012-06-01

219

Activity of Wind-Blown Sand and the Formation of Feathered Sand Ridges in the Kumtagh Desert, China  

NASA Astrophysics Data System (ADS)

We study the activity of wind-blown sand and its effects on the evolution of feathered sand ridges in the Kumtagh Desert, China, and attempt to reveal the formation process of feathered sand ridges using wind-tunnel experiments, remote sensing data, and detailed field observations from 2005 to 2008. The prevailing wind direction in the Kumtagh Desert is easterly in winter and north-easterly in other seasons. The average annual wind speed is 5.9 ms-1, and winds sufficiently strong to entrain sand occur on 143 days per annum. The sand transport rate within 0.4 m of the ground is strongly influenced by local landforms, and is related to wind speed by a power function. Wind erosion occurs on the crest, the windward slope of crescent sand ridges and inter-ridge sand strips, where the blowing sand cloud is in an unsaturated state; in contrast, sand accumulation occurs on the leeward slope of the crescent sand ridges, where the blowing sand cloud is in an over-saturated state. These results indicate that the development of feathered sand ridges in the Kumtagh Desert is mainly controlled by the local wind regime. The dominant winds (from the north, north-north-east and north-east) and additional winds (from the east-north-east, east and east-south-east) determine the development of crescent sand ridges, but winds that are approximately parallel to sand ridges form the secondary inter-ridge sand strips.

Liao, Kongtai; Qu, Jianjun; Tang, Jinnian; Ding, Feng; Liu, Hujun; Zhu, Shujuan

2010-05-01

220

The application of baghouse fines in Taiwan  

Microsoft Academic Search

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

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

2006-01-01

221

Origin and evolution of the Candlelight Reef-Sand Clay system, St. Croix.  

USGS Publications Warehouse

Candlelight reef is the buttressing western terminus of the northeastern St. Croix reef system, caused by a combination of paleotopography and longshore drift which created a stable pile of detrital material at this position. Reef colonization proceeded eastward along the former slope break on the limestone terrace; turbid gyres along the eastern margin of the former Southgate drainage prevented further westward colonization. The presence of detrital cobbles in Sand Cay and Candlelight reef is explained by this model. An unconformity between underlying fine-grained quartzose rocks and overlying carbonates, need represent only an eustatic sea level rise rather than any fundamental tectonic event.-from Author

Gerhard, L. C.

1981-01-01

222

Quantum Fine-Grained Entropy  

E-print Network

Regarding the strange properties of quantum entropy and entanglement, e.g., the negative quantum conditional entropy, we revisited the foundations of quantum entropy, namely, von Neumann entropy, and raised the new method of quantum fine-grained entropy. With the applications in entanglement theory, quantum information processing, and quantum thermodynamics, we demonstrated the capability of quantum fine-grained entropy to resolve some notable confusions and problems, including the measure of entanglement and quantumness, the additivity conjecture of entanglement of formation etc, and the definition of temperature for single quantum system.

Dong-Sheng Wang

2012-05-06

223

Basic Soil Properties of a Number of Artificial Clay - Sand Mixtures Determined as a Function of Sand Content  

NASA Astrophysics Data System (ADS)

Soil mixtures were composed from the Polish Neogene clays occurring on the Polish Lowland and the fine-grained dune sand in weight proportions of the dried components. As the products of mixing, new soils were obtained, having modified physical, mechanical and screening properties as a function of their different granular and mineral composition. The granular composition varies from the soils which are similar to clays, through the clay loam, sandy clay loam up to sandy loam. With comparison to the untreated clay, soil mixtures by far compact better and achieve lower values of porosity index n and void ratio e (n 27-22%; e 0.37-0.29; raw clay n 43%, e 0.76), and therefore they achieve lower values of coefficient of permeability (k 1.83 · 10-9 to 2 · 10-11 m/s) by maximum compaction. The soil mixtures show lower values of free swelling and linear shrinkage (FSHG 40-20%; LS 10.6-7.4%; raw clay: FSHG 70%; LS 14.7%. The mentioned features are crucial while selecting the mineral component of the lining system of burdensome objects such as landfills. Moreover, shear parameters of clay mixtures are improved as compared to the raw clay: starting from the angle of internal friction &varphi 6.2(°) ; and cohesion c 46.6 kPa by raw clay, to &varphi 33.5(°) ; and c 43.5 kPa by the soil mixture showing the highest sand content among the modeled soils. The values of the mentioned parameters are fundamental by selecting of mineral lining, and in course of construction of earth objects.

Luczak-Wilamowska, Beata

224

Planet-wide sand motion on mars  

USGS Publications Warehouse

Prior to Mars Reconnaissance Orbiter data, images of Mars showed no direct evidence for dune and ripple motion. This was consistent with climate models and lander measurements indicating that winds of sufficient intensity to mobilize sand were rare in the low-density atmosphere. We show that many sand ripples and dunes across Mars exhibit movement of as much as a few meters per year, demonstrating that Martian sand migrates under current conditions in diverse areas of the planet. Most motion is probably driven by wind gusts that are not resolved in global circulation models. A past climate with a thicker atmosphere is only required to move large ripples that contain coarse grains. ?? 2012 Geological Society of America.

Bridges, N. T.; Bourke, M. C.; Geissler, P. E.; Banks, M. E.; Colon, C.; Diniega, S.; Golombek, M. P.; Hansen, C. J.; Mattson, S.; Mcewen, A. S.; Mellon, M. T.; Stantzos, N.; Thomson, B. J.

2012-01-01

225

Flocculation settling characteristics of mud: sand mixtures  

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

226

Analytical mesoscale modeling of aeolian sand transport  

E-print Network

We analyze the mesoscale structure of aeolian sand transport, based on a recently developed two-species continuum model. The calculated sand flux and important average characteristics of the grain trajectories are found to be in remarkable agreement with field and wind-tunnel data. We conclude that the essential mesoscale physics is insensitive to unresolved details on smaller scales and well captured by the coarse-grained analytical model, thus providing a sound basis for precise and numerically efficient mesoscale modeling of aeolian structure formation.

Marc Lämmel; Anne Meiwald; Klaus Kroy

2014-05-03

227

Investigation of sands subjected to dynamic loading  

E-print Network

that a closer study was needed on Equation 4. Before such a study, how- ever, some addi. tional testing was done on sands taken from actual locations where piles had been driven and Smith's equations, adapted 9 to a computer program, had been employed..., employed in the computer studies of field tests on Victoria and Arkansas sands, varied from 0. 00 to 0. 30. These values were assigned, based on approximations, to yield the best computer analysis corresponding to the pile load tests done in the field...

Reeves, Gary Neil

2012-06-07

228

Experimental Investigation of Concrete with Combined High alumina cement, Silica fume and M-Sand  

NASA Astrophysics Data System (ADS)

Concrete is by far the most widely used construction material today. It is estimated that present consumption of concrete in the world is of the order of 10 billion tonnes every year. The cement industry is responsible for about 6% of all CO2 emissions. So nowadays there is a great interest in the development and implementation of various alternatives to Portland cement as a binder in concrete and also alternatives to fine and coarse aggregates in concrete to reduce the energy used in production of Portland cement clinker and the associated greenhouse gas emission and also for reducing resources consumption by proper recycling. This research work is carried out in order to explore the effect of various replacement percentages of cement by combined High alumina cement with silica fume and also the fine aggregate is fully replaced with manufacturing sand. Conclusion is made based on the comparison between the performance of blended cement concrete and conventional concrete.

Joseph, Dona Maria; Devi, Manjula; Senthilkumar, S.

2013-03-01

229

Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux.  

PubMed

Coupling between surface winds and saltation is a fundamental factor governing geological activity and climate on Mars. Saltation of sand is crucial for both erosion of the surface and dust lifting into the atmosphere. Wind tunnel experiments along with measurements from surface meteorology stations and modelling of wind speeds suggest that winds should only rarely move sand on Mars. However, evidence for currently active dune migration has recently accumulated. Crucially, the frequency of sand-moving events and the implied threshold wind stresses for saltation have remained unknown. Here we present detailed measurements of Nili Patera dune field based on High Resolution Imaging Science Experiment images, demonstrating that sand motion occurs daily throughout much of the year and that the resulting sand flux is strongly seasonal. Analysis of the seasonal sand flux variation suggests an effective threshold for sand motion for application to large-scale model wind fields (1-100?km scale) of ?(s)=0.01±0.0015?N?m(-2). PMID:25268931

Ayoub, F; Avouac, J-P; Newman, C E; Richardson, M I; Lucas, A; Leprince, S; Bridges, N T

2014-01-01

230

Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux  

NASA Astrophysics Data System (ADS)

Coupling between surface winds and saltation is a fundamental factor governing geological activity and climate on Mars. Saltation of sand is crucial for both erosion of the surface and dust lifting into the atmosphere. Wind tunnel experiments along with measurements from surface meteorology stations and modelling of wind speeds suggest that winds should only rarely move sand on Mars. However, evidence for currently active dune migration has recently accumulated. Crucially, the frequency of sand-moving events and the implied threshold wind stresses for saltation have remained unknown. Here we present detailed measurements of Nili Patera dune field based on High Resolution Imaging Science Experiment images, demonstrating that sand motion occurs daily throughout much of the year and that the resulting sand flux is strongly seasonal. Analysis of the seasonal sand flux variation suggests an effective threshold for sand motion for application to large-scale model wind fields (1–100?km scale) of ?s=0.01±0.0015?N?m?2.

Ayoub, F.; Avouac, J.-P.; Newman, C. E.; Richardson, M. I.; Lucas, A.; Leprince, S.; Bridges, N. T.

2014-09-01

231

Thermal Gradient Fining of Glass  

NASA Technical Reports Server (NTRS)

Molten glass fined (cleared of bubbles) by heating with suitable temperature gradient, according to preliminary experiments. Temperature gradient produces force on gas bubbles trapped in molten glass pushing bubbles to higher temperature region where they are collected. Concept demonstrated in experiments on Earth and on rocket.

Wilcox, W.

1983-01-01

232

Fine Arts. [SITE 2002 Section].  

ERIC Educational Resources Information Center

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

Robin, Bernard, Ed.

233

Fine Arts Education. Research Brief  

ERIC Educational Resources Information Center

What are the benefits of a Fine Arts education? With the advent of the No Child Left Behind Act of 2000, extreme pressure has been put on schools to concentrate the majority of their efforts and resources on reading, math and science skills. Yet, NCLB also states that every child should be well-versed in the arts. Some research has shown that when…

Walker, Karen

2006-01-01

234

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

NASA Astrophysics Data System (ADS)

Sand dunes typically migrate in opposing directions along the two sides of sand banks, reflecting a circulation driven by tidal current asymmetry, but it has been less clear how this pattern is distorted where banks intersect the coastline. The nearshore end of Helwick Sands, a banner bank in the Bristol Channel, was surveyed three times over three years, twice with a high-resolution multibeam echo-sounder. In both multibeam surveys, an unusual geometry was found over the crest of the bank, whereby dunes connect continuously with the dunes on the flanks, despite the flank dunes migrating in opposite directions. The crestal dunes thus appear to realign rapidly. We suggest that this morphological behaviour arises here because of vigorous wave-driven transport and because surface waves propagate almost exactly parallel to the crestal dunes. Sand transported parallel to the crestal dunes ensures that efficient reconnection occurs with dunes migrating along the flanks, particularly at low tide when wave currents are more strongly felt at the bed.

Schmitt, Thierry; Mitchell, Neil C.

2014-03-01

235

Yellow perch embryo-larval survival and growth in surface waters associated with oil-sands mining  

SciTech Connect

As part of their land reclamation strategy, Syncrude Canada Ltd. is currently developing environmentally acceptable tailings disposal methods. Fine tailings, a suspension of clay and residual bitumen, is the waste product from oil sands extraction. Fine-tailings contain naphthenic acids, a group of saturated aliphatic and alicyclic carboxylic acids, which occur naturally in petroleum and are partly responsible for the toxicity of process water. The wet landscape method involves covering fine tails with a layer of water such that a self-sustaining ecosystem can be established. A 5 ha demonstration pond with a bottom of fine-tailings was constructed and stocked with yellow perch for experimental purposes. Two other reclaimed ponds formed with oil-sands overburden material were also stocked with perch. Adult perch sampled in the fall of 1995 from the experimental and reclaimed ponds exhibited a 2-fold induction of MFO activity compared to the source lake; indicating organic compound exposure. Perch from one of the reclaimed ponds showed significantly reduced circulating reproductive hormone levels, gonad size and smaller ovarian follicles. Reproductive parameters were not different between the source lake and the remaining ponds. Paired lab and field experiments were conducted to determine if contaminants present would be detrimental to egg viability and development of larvae either through direct exposure of spawned eggs or indirectly by effecting oogenesis. An early life stage toxicity test was also performed using commercially available naphthenic acid standard. Endpoints measured were percent fertilization, percent hatch, mortality, deformities, timing of developmental periods and larval growth.

Peters, L.E.; Heuvel, M.R. van den; Dixon, D.G. [Univ. of Waterloo, Ontario (Canada); Power, M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada); Boerger, H.; MacKinnon, M.D.; Meer, T. Van [Syncrude Canada, Fort McMurray, Alberta (Canada)

1995-12-31

236

Conoco's South Texas Tar Sands Project  

Microsoft Academic Search

A description is given of activities and first pilot results of the South Texas Tar Sands Project. Included is a description of a new process for which a patent has been applied. The process, known as Fracture Assisted Steamflood Technology, or FAST, is a blend of high pressure steam flooding and horizontal fracturing techniques. 169,000 barrels of tar were produced

Oshlo

1981-01-01

237

Animals Between the Sand Grains - Meiofauna  

NSDL National Science Digital Library

In this lab activity, students will observe the minute animals that live between sand grains. The activity includes a list of materials, procedures, and discussion question. It is supplemented with reference images and a list of species and their phyla, including Gastrotrichicha, Crustacea/Ostracoda, Crustacea/Copepoda/Harpacticoidea, Nematoda, Turbellaria, Nemertina, Archiannelida, Polychaeta, and Oligochaeta.

Center, Ucla M.

238

EXPRESSING SUPPLY LIMITATION IN SAND SALTATION  

EPA Science Inventory

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

239

Fracturing yields oil from poorly consolidated sands  

Microsoft Academic Search

The technique of fracturing poorly consolidated sandstone reservoirs and filling them with a thick multilayer of proppant has proven successful since sustained production has been obtained from zones previously not producible. Since there was no significant difference in results when fluids of varying polymer concentrations were used, the least expensive fluid was applied. The 70\\/140 mesh sand used as a

S. A. Lambert; R. T. Dolan; J. P. Gallus

1984-01-01

240

Oil shale, tar sands, and related materials  

Microsoft Academic Search

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

Stauffer

1981-01-01

241

Macrodispersion in Sand-Shale Sequences  

Microsoft Academic Search

Macrodispersion in sand-shale sequences is investigated by a series of numerical tracer tests. Hydraulic conductivity is modeled as a binary, spatially correlated random function. Realizations of the random conductivity field are simulated on a nodal grid discretizing the heterogeneous formation. Corresponding realizations of the random velocity field are obtained by solving the equation for saturated steady state flow. Particle tracking,

Alexandre J. Desbarats

1990-01-01

242

Macrodispersion in sand-shale sequences  

Microsoft Academic Search

Macrodispersion in sand-shale sequences is investigated by a series of numerical tracer tests. Hydraulic conductivity is modeled as a binary, spatially correlated random function. Realizations of the random conductivity field are simulated on a nodal grid discretizing the heterogeneous formation. Corresponding realizations of the random velocity field are obtained by solving the equation for saturated steady state flow. Particle tracking,

Alexandre J. Desbarats

1990-01-01

243

SANDIA REPORT SAND2001-0643  

E-print Network

), fiber-optic sensors, and surface-acoustic-wave sensors. However, very few chemical sensors have been; and (4) optical sensors. Based on the review criteria set forth in this report, the most viable sensorsSANDIA REPORT SAND2001-0643 Unlimited Release Printed March 2001 Review of Chemical Sensors for In

Ho, Cliff

244

SOURCE ASSESSMENT: TRANSPORT OF SAND AND GRAVEL  

EPA Science Inventory

This report describes a study of atmospheric emissions from the transport of sand and gravel on unpaved roads. The potential environmental effect of this emission source was evaluated using source severity, defined as the ratio of the time-averaged maximum ground level concentrat...

245

SANDIA REPORT SAND2006-5315  

E-print Network

-Mail: reports@adonis.osti.gov Online ordering: http://www.osti.gov/bridge Available to the public from U.SSANDIA REPORT SAND2006-5315 Unlimited Release Printed August 2006 A generating set direct search. Kolda, R. M. Lewis, and V. Torczon Prepared by Sandia National Laboratories Albuquerque, New Mexico

Lewis, Robert Michael

246

SAND2000-8213 Unlimited Release  

E-print Network

search, direct search, fault tolerance, distributed computing, cluster computing. #3; Email: pdhough@ca.sandia.gov 2 R n and f : R n ! R. We introduce a family of asynchronous parallel pattern search (APPS) methodsSAND2000-8213 Unlimited Release Printed January 2000 Asynchronous Parallel Pattern Search

Kolda, Tamara G.

247

Two Tales of Martian Sands and Dust  

NASA Astrophysics Data System (ADS)

We invert for mineral abundances and grain sizes of dunes at Endeavour and Gale craters from CRISM data and Hapke's theory. Our results are consistent with ground truth from the rovers. We detect dust on dunes at Gale, and relate it to sand activity.

Lapotre, M. G. A.; Ehlmann, B. L.; Arvidson, R. E.; Minson, S. E.; Ayoub, F.; Bridges, N.

2014-07-01

248

NASA White Sands Test Facility Remote Hypervelocity Test Laboratory  

NASA Video Gallery

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

249

Mineral resource of the month: industrial sand and gravel  

USGS Publications Warehouse

With many diverse uses, industrial sand and gravel, also known as silica sand, is one of the most important nonmetallic minerals in the world. Industrial sand and gravel is a mining industry term used for sands that have a very high percentage of silicon dioxide, or greater than 95 percent quartz. Deposits of industrial sand and gravel can be found virtually everywhere on Earth, but are less widespread than deposits of common construction sand and gravel. Industrial sand and gravel is distinctive in grain size, hardness, inertness and resistance to high temperature and chemical action. Beverage containers, fiberglass insulation, fiber-optic cables and light bulbs are just some of today’s many products produced from industrial sand and gravel.

Dolley, Thomas P.

2007-01-01

250

Marine gas hydrates in thin sand layers that soak up microbial methane  

NASA Astrophysics Data System (ADS)

At Site U1325 (IODP Exp. 311, Cascadia margin), gas hydrates occupy 20-60% of pore space in thin sand layers (< 5 cm) surrounded by fine-grained intervals (2.5 m thick on average) that contain little or no hydrate. This is a common occurrence in gas hydrate-bearing marine sequences, and it has been related to the inhibition of hydrate formation in the small pores of fine-grained sediments. This paper applies a mass balance model to gas hydrate formation in a stack of alternating fine- and coarse-grained sediment layers. The only source of methane considered is in situ microbial conversion of a small amount of organic carbon (< 0.5% dry weight fraction). The results show that in a sequence such as that at Site U1325 the methane concentration never reaches the supersaturation needed to form gas hydrates in the fine-grained layers. Methane generated in these layers is transported by diffusion into the coarse-grained layers where it forms concentrated gas hydrate deposits. The vertical distribution and amount of gas hydrate observed at Site U1325 can be explained by in situ microbial methane generation, and a deep methane source is not necessary.

Malinverno, Alberto

2010-04-01

251

Imaging of Acoustic Waves in Sand  

SciTech Connect

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

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

2003-08-01

252

Inorganic nitrogen transformations within permeable carbonate sands  

NASA Astrophysics Data System (ADS)

A combination of in-situ push pull tests and a flow through reactor trial were used to quantify the inorganic nitrogen sinks in the permeable carbonate sands of a tropical coral cay (Heron Island - Great Barrier Reef). Addition of dissolved inorganic nitrogen (DIN in the form of nitrate - NO3-, and ammonium - NH4+) directly into sediment porewater resulted in uptake of up to 97% and 60% of added DIN respectively. The initial push pull experiment qualitatively showed that dissimilatory nitrate reduction to ammonia (DNRA), denitrification and nitrification were all active in the sediments. A flow through reactor experiment provided a more detailed approach to quantify these processes and showed that both denitrification and DNRA occurred within the sands at rates of 7.3 and 5.5 ?mol N cm-3 d-1, respectively. Unexpectedly the addition of labile organic material (fresh coral spawn) to the permeable sands did not result in the release of DIN from the reactors, on the contrary it resulted in the increased uptake of both NO3- and NH4+. This was most likely because of the stimulated N uptake associated with the addition of high C:N coral spawn material. The bulk of NH4+ produced via DNRA was found to be adsorbed to sediments within the reactor and was not released with the outlet water. A mass balance over the entire experimental period showed that more inorganic N was retained within the sediments than lost as gaseous products. Our results point to permeable carbonate sands acting as reservoirs of N under the influence of advective flow, even during sudden enrichment periods such as those following coral mass spawning. This implies that permeable carbonate sands may help to buffer coral reefs during periods of extreme oligotrophy.

Erler, Dirk V.; Santos, Isaac R.; Eyre, Bradley D.

2014-04-01

253

Arsenate removal from water using sand–red mud columns  

Microsoft Academic Search

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

Hülya Genç-Fuhrman; Henrik Bregnhøja; David M McConchie

2005-01-01

254

Geology Fieldnotes: White Sands National Monument, New Mexico  

NSDL National Science Digital Library

The White Sands National Monument site contains park geology information, maps, related links, and visitor information. The park geology section discusses the park's geologic history, the formation of the gypsum sand dunes, and the four types of dunes found at the White Sands National Monument: dome, barchan, transverse, and parabolic. The park maps section includes a map of the White Sands National Monument and the surrounding area, showing the location of each type of dune.

255

Process and apparatus for stripping solids from bituminous sand  

Microsoft Academic Search

A process and apparatus for the recovery of bitumen from bituminous sand utilize a flotation gas which is passed through a bituminous sand slurry. In the process, a slurry of bituminous sand is introduced into the upper portion of an inverted-cone-shaped flotation tank (or ''stripper'') containing a column of water. The slurry may be formed by any conventional means such

1966-01-01

256

Well completion process for formations with unconsolidated sands  

DOEpatents

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

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

2003-04-29

257

7 CFR 319.56-57 - Sand pears from China.  

... 2014-01-01 false Sand pears from China. 319.56-57 Section 319.56-57...Vegetables § 319.56-57 Sand pears from China. Fresh sand pears (Pyrus pyrifolia ) from China may be imported into the United States...

2014-01-01

258

7 CFR 319.56-57 - Sand pears from China.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Sand pears from China. 319.56-57 Section 319.56-57...Vegetables § 319.56-57 Sand pears from China. Fresh sand pears (Pyrus pyrifolia ) from China may be imported into the United States...

2013-01-01

259

Tar sands. (Latest citations from the COMPENDEX database). Published Search  

SciTech Connect

The bibliography contains citations concerning mining of tar sands and the recovery of bitumen and other materials from tar sands. The physical and chemical properties of tar sands are discussed, and the economics of their use are considered. Processes include alkaline extraction, water cracking, catalytic cracking, and in situ combustion. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-05-01

260

An overview of Canadian oil sand mega projects  

Microsoft Academic Search

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

R. Paes; M. Throckmorton

2008-01-01

261

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

USGS Publications Warehouse

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

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

2008-01-01

262

Two Proofs of Fine's Theorem  

E-print Network

Fine's theorem concerns the question of determining the conditions under which a certain set of probabilities for pairs of four bivalent quantities may be taken to be the marginals of an underlying probability distribution. The eight CHSH inequalities are well-known to be necessary conditions, but Fine's theorem is the striking result that they are also a sufficient condition. It has application to the question of finding a local hidden variables theory for measurements of pairs of spins for a system in an EPRB state. Here we present two simple and self-contained proofs of Fine's theorem in which the origins of this non-obvious result can be easily seen. The first is a physically motivated proof which simply notes that this matching problem is solved using a local hidden variables model given by Peres. The second is a straightforward algebraic proof which uses a representation of the probabilities in terms of correlation functions and takes advantage of certain simplifications naturally arising in that representation. A third, unsuccessful attempt at a proof, involving the maximum entropy technique is also briefly described

J. J. Halliwell

2014-03-27

263

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

Code of Federal Regulations, 2013 CFR

...Disposal plan for embedded gravel, sand or stone. 644.505 Section 644.505 National...Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior to offering sand, gravel,...

2013-07-01

264

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

...Disposal plan for embedded gravel, sand or stone. 644.505 Section 644.505 National...Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior to offering sand, gravel,...

2014-07-01

265

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

Code of Federal Regulations, 2012 CFR

...Disposal plan for embedded gravel, sand or stone. 644.505 Section 644.505 National...Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior to offering sand, gravel,...

2012-07-01

266

York University Faculty of Fine Arts  

E-print Network

collaborative research, securing external funding, making links across art, computerYork University Faculty of Fine Arts Canada Research Chair (Tier 2) in - Interactive Information Visualization The Faculty of Fine Arts at York University

267

Vegetation and soil water interactions on a tailings sand storage facility in the athabasca oil sands region of Alberta Canada  

Microsoft Academic Search

The relationship between vegetation and soil water was studied on the Syncrude South West Sand Storage facility in the Athabasca Oil Sands region of Alberta, Canada. Soil water and relevant soil chemical and physical properties were measured at the soil surface, as well as above and below the reclamation soil and tailings sand interface, in areas of low and high

M. A. Naeth; D. S. Chanasyk; T. D. Burgers

2011-01-01

268

A Fine-Grain Multithreading Superscalar Architecture  

E-print Network

A Fine-Grain Multithreading Superscalar Architecture Mat Loikkanen and Nader Bagherzadeh Department In this study we show that fine-grain multithreading is an effective way to increase instruction, that are capable of performing various operations in parallel, are vulnerable. A fine-grain multithreading paradigm

Bagherzadeh, Nader

269

Conoco's South Texas Tar Sands Project  

SciTech Connect

A description is given of activities and first pilot results of the South Texas Tar Sands Project. Included is a description of a new process for which a patent has been applied. The process, known as Fracture Assisted Steamflood Technology, or FAST, is a blend of high pressure steam flooding and horizontal fracturing techniques. 169,000 barrels of tar were produced before shutdown in June 1980, with a ratio of 10.6 barrels of steam injected per barrel of tar. The primary application of FAST is in reserviors that contain extremely viscous tar or are thin enough that heat losses to the confining strata are a problem. Commercialization of the project is expected to require large amounts of lead time, capital and manpower. Tar sands activities are said to be synfuels projects rather than an extension of heavy activities. (JMT)

Oshlo, E.L.

1981-06-01

270

Fracturing yields oil from poorly consolidated sands  

SciTech Connect

The technique of fracturing poorly consolidated sandstone reservoirs and filling them with a thick multilayer of proppant has proven successful since sustained production has been obtained from zones previously not producible. Since there was no significant difference in results when fluids of varying polymer concentrations were used, the least expensive fluid was applied. The 70/140 mesh sand used as a fluid loss additive apparently was effective and possibly less damaging than silica flour. Larger sized sand pumped at the end of treatments did not have a discernible effect on production rate, but wells treated with Clay Acid apparently produced at higher rates than wells not treated. The stimulation method described for poorly consolidated, sandstone reservoirs may be expected to be effective in areas other than the Cook Inlet of Alaska, i.e., in areas where conventional fracturing in relatively soft formations has not been successful.

Lambert, S.A.; Dolan, R.T.; Gallus, J.P.

1984-05-01

271

Analysis of Wind-blown Sand Movement over Transverse Dunes.  

PubMed

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. PMID:25434372

Jiang, Hong; Huang, Ning; Zhu, Yuanjian

2014-01-01

272

Fusion of arkosic sand by intrusive andesite  

USGS Publications Warehouse

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.

Bailey, Roy A.

1954-01-01

273

Guide to preparing SAND reports. Revised  

SciTech Connect

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.

Locke, T.K. [ed.

1996-04-01

274

Solvent extraction of Southern US tar sands  

SciTech Connect

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.

Penney, W.R.

1990-01-01

275

Strength and sintering effects at ejection of explosively driven sand  

NASA Astrophysics Data System (ADS)

A description of the response of sand to extreme loads is very important for the evaluation of the sand ejecta impact effects on various targets. Sand is a complex material to simulate because of its porosity where the inter-phase equilibrium is hard to achieve under transient shock wave loading. A previously developed two-phase model with strength has been implemented in CTH and applied to sand. The shock response of the sand, including the Hugoniot abnormality known from the literature for highly porous silica, is adequately described with the material model. The sand unloading effects appearing as the ejecta are observed in the present work using dynamic flash X-ray of an aluminium target plate loaded by limestone sand ejecta from the detonation of a buried high explosive charge. The CTH modelling results compared with the flash X-ray images have demonstrated good agreement, particularly, in the description of momentum transfer to the target.

Resnyansky, A. D.; Weckert, S. A.

2014-05-01

276

The sedimentary structure of linear sand dunes  

PubMed

Linear sand dunes--dunes that extend parallel to each other rather than in star-like or crescentic forms--are the most abundant type of desert sand dune. But because their development and their internal structure are poorly understood, they are rarely recognized in the rock record. Models of linear dune development have not been able to take into account the sub-surface structure of existing dunes, but have relied instead either on the extrapolation of short-term measurements of winds and sediment transport or on observations of near-surface internal sedimentary structures. From such studies, it has not been clear if linear dunes can migrate laterally. Here we present images produced by ground penetrating radar showing the three-dimensional sedimentary structure of a linear dune in the Namib sand sea, where some of the world's largest linear dunes are situated. These profiles show clear evidence for lateral migration in a linear dune. Moreover, the migration of a sinuous crest-line along the dune produces divergent sets of cross-stratification, which can become stacked as the dune height increases, and large linear dunes can support superimposed dunes that produce stacked sets of trough cross-stratification. These clear structural signatures of linear dunes should facilitate their recognition in geological records. PMID:10894538

Bristow; Bailey; Lancaster

2000-07-01

277

Dynamic effective shear strength of saturated sand  

NASA Astrophysics Data System (ADS)

The dynamic effective shear strength of saturated sand under cyclic loading is discussed in this paper. The discussion includes the transient time dependency behaviors based on the analysis of the results obtained in conventional cyclic triaxial tests and cyclic torsional shear triaxial tests. It has been found that the dynamic effective shear strength is composed of effective frictional resistance and viscous resistance, which are characterized by the strain rate dependent feature of strength magnitude, the coupling of consolidation stress with cyclic stress and the dependency of time needed to make the soil strength sufficiently mobilized, and can also be expressed by the extended Mohr-Coulomb's law. The two strength parameters of the dynamic effective internal frictional angle ?d and the dynamic viscosity coefficient ? are determined. The former is unvaried for different number of cyclic loading, dynamic stress form and consolidation stress ratio. And the later is unvaried for the different dynamic shear strain ratedot ? _t developed during the sand liquefaction, but increases with the increase of initial density of sand. The generalization of dynamic effective stress strength criterion in the 3-dimensional effective stress space is studied in detail for the purpose of its practical use.

Shengjun, Shao; Dingyi, Xie

2002-08-01

278

Stream sediment decomposition in contrasting glacial sand, peat and muck reaches of a wetland stream  

NASA Astrophysics Data System (ADS)

Low-gradient peatland streams often have unconventional channel forms which are hypothesized to be driven by variability in groundwater discharge and organic matter production and decomposition. These aquatic systems are also regionally important sources of CO2 and CH4, and knowledge of spatial controls of decomposition could help constrain the regional carbon budget. We investigated how sediment texture, organic matter content, and groundwater exchange affect the metabolism of stream sediments in a wetland stream in northern Wisconsin, U.S. We compared an organic-rich wetland reach with adjacent glacial sand reaches and also identified six cross-sections in the wetland where fine, unconsolidated organic sediments (muck) were positioned adjacent to a solid peat bed. Based on sediment temperature anomalies and substantial previous work on groundwater hydrology, we found that loose organic sediments were always associated with groundwater upwelling, which was not seen in the adjacent peat. Sediments from sand and muck cores were incubated aerobically, and at each wetland cross-section we incubated cores under both aerobic and anaerobic conditions. Aerobic respiration rates in muck sediments were higher than for glacial sands, and there were substantial localized differences in the wetland sediments associated with groundwater upwelling. We found that aerobic and anaerobic respiration were higher in muck sediments than in peat (nearly threefold, p<0.05) which confirms that decomposition is more rapid in sediments receiving constant groundwater discharge. Sediment organic matter was lower in muck compared to solid peat sediments, but much higher than in sand. The resulting variation in sediment bioavailability and quantity support the hypothesis that biological processes, rather than purely physical processes, dictate the unique cross-sectional and planform geometry of peatland stream channels. Further, these patterns can be used to explain previously documented reach and regional scale variability in stream greenhouse gas emissions.

Spawn, S.; Crawford, J. T.; Stanley, E. H.

2013-12-01

279

Blending foundry sands with soil: Effect on dehydrogenase activity.  

PubMed

Each year U.S. foundries landfill several million tons of sand that can no longer be used to make metalcasting molds and cores. A possible use for these materials is as an ingredient in manufactured soils; however, potentially harmful metals and resin binders (used to make cores) may adversely impact the soil microbial community. In this study, the dehydrogenase activity (DHA) of soil amended with molding sand (clay-coated sand known as "green sand") or core sands at 10%, 30%, and 50% (dry wt.) was determined. The green sands were obtained from iron, aluminum, and brass foundries; the core sands were made with phenol-formaldehyde or furfuryl alcohol based resins. Overall, incremental additions of these sands resulted in a decrease in the DHA which lasted throughout the 12-week experimental period. A brass green sand, which contained high concentrations of Cu, Pb, and Zn, severely impacted the DHA. By week 12 no DHA was detected in the 30% and 50% treatments. In contrast, the DHA in soil amended with an aluminum green sand was 2.1 times higher (all blending ratios), on average, at week 4 and 1.4 times greater (30% and 50% treatments only) than the controls by week 12. In core sand-amended soil, the DHA results were similar to soils amended with aluminum and iron green sands. Increased activity in some treatments may be a result of the soil microorganisms utilizing the core resins as a carbon source. The DHA assay is a sensitive indicator of environmental stress caused by foundry sand constituents and may be useful to assess which foundry sands are suitable for beneficial use in the environment. PMID:15975632

Dungan, Robert S; Kukier, Urzsula; Lee, Brad

2006-03-15

280

Liquefaction susceptibility of fine-grained soils: preliminary study report. Final report, September 1985-March 1986  

SciTech Connect

Soil liquefaction, a hazardous ground failure induced by strong motion earthquakes, can cause catastrophic damage to structures such as dams, bridges, power plants, and water-front structures and may involve great losses of life. Examples of liquefaction and resulting damage were observed during the Alaska (1964), Niigata, Japan (1964), and Tangshan, China (1976), earthquakes. Ground failure due to earthquake-induced soil liquefaction may manifest itself as excessive settlement, loss of bearing capacity, sand boiling, and flow slides. The liquefaction potential of clean sands has been studied extensively for the last two decades. However, case histories revealed that liquefied sands were seldom clean. They may contain various percentages of silt or clay or both. In fact, the Chinese observation in the Tansghan earthquake indicated that some cohesive soils may have liquefied. If this indeed had happened, then structures underlain by fine-grained soils, with a marginal safety factor based on the liquefaction criteria normally applied to sands, may actually be unsafe. Thus there is an urgent need for establishing new criteria for the liquefaction susceptibility of soils to include those identified as fine-grained. The author, Professor N.Y. Chang of the University of Colorado at Denver, visited several Chinese agencies and and universities in and near Beijing, China, in the summer of 1985 in an attempt to investigate and verify reported data on the liquefaction of cohesive soils during the Tangshan earthquake of 1976 and to negotiate cooperative research into the problem. This report presents the result of supportive literature review and the findings of the China trip.

Chang, N.Y.

1987-09-01

281

Process for fine coal cleaning  

SciTech Connect

This patent describes a process for automatically controlling a fine coal cleaning and recovery circuit in which coal is separated from ash forming impurities in a flotation cell wherein the improvement comprises: placing a photoconductor in tailings from the flotation cell to monitor the coal recovery of the cell and automatically control the amount of additive supplied to the cell in response to the monitored coal recovery in the cell to optimize coal recovery from the cell; and sensing the level of the flotation product in the filter tub and automatically adjust the amount of flocculant supplied to the filter tub in response to the sensed product level to maximize coal recovery.

Fonseca, A.G.

1989-03-07

282

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

USGS Publications Warehouse

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

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

2002-01-01

283

Granular Banding - the Fine Structure  

NASA Astrophysics Data System (ADS)

Solid-liquid two-phase flow in a partially filled, horizontally rotating cylinder is studied experimentally. This system can display several different flow states. The rotation rate, the filling level and the fluid properties determine which state is adopted. In the phase plane different states are separated from each other by sharp transition boundaries. The influence of granular additives on these boundaries is investigated. Results for particles of different sizes, densities and shapes are presented. Under certain conditions the granular additives come out of suspension to form regularly spaced circumferential bands on the inner cylinder wall [1,2]. We report the observation of a new phenomenon by which these primary bands develop a fine structure. The fine structure is characterized by each primary band adopting a compound structure consisting of three narrower secondary rings [3]. References: [1] Boote & Thomas, Phys. Fluids vol. 11(8), p. 2020 (1999), [2] Tirumkudulu et al., Phys. Fluids vol. 12(6), p. 1615 (2000), [3] Thomas et al., Phys. Fluids vol. 13 (9), pages not yet known (2001)

Thomas, Peter J.; Riddell, Gareth D.; King, Gregory P.

2001-11-01

284

Physically based model of downstream fining in bedrock streams with lateral input  

NASA Astrophysics Data System (ADS)

Bed load particles in bedrock streams receiving lateral input from hillslopes may or may not show a clear, monotonic pattern of size reduction in the downstream direction. Both abrasion and selective sorting may play important roles in generating downstream fining. The objective of this study is to develop a physically based model of downstream fining in bedrock streams with lateral input based on both processes. A surface-based gravel transport relation for the size mixture is employed to account for the effect of selective sorting (differential transport). While the model produces silt and sand by abrasion, it is also assumed to loosely capture particle fracturing via a lumped abrasion coefficient embodied in Sternberg's law. The model is here tested against field data from Vieux Habitants River in Guadeloupe Island, which is located in the Caribbean Sea. The river shows clear downstream fining, and this pattern is captured reasonably well by the model. The model results indicate that abrasion (including fracturing) is solely responsible for the downstream fining pattern for most of the study reach of the Vieux Habitants River. Sensitivity analysis of the model has also been performed. The model results suggest that, in general, selective sorting by differential transport can play a role in downstream fining only in cases of streams with relatively fine gravel sizes and lower slopes. The results also indicate that abrasion (including fracturing) and selective sorting can be equally important for downstream fining in bedrock rivers. The results also suggest that future work should explicitly consider fracturing (comminution) separately from abrasion (wear) rather than lumping them in a Sternberg-type coefficient.

Chatanantavet, Phairot; Lajeunesse, Eric; Parker, Gary; Malverti, Luce; Meunier, Patrick

2010-02-01

285

Depositional models of sandy debrites and turbidites of Palaeogene reservoir sands in deep-lacustrine environments, South China  

NASA Astrophysics Data System (ADS)

Two depositional models are proposed for deep-lacustrine petroleum reservior sands (Palaeogene) in the Fushan Sag, Beibuwan Basin, South China. This facies trend is used as a template for predicting the distribution of reservoir facies of the Fushan oilfield. Based on examination of 150m of conventional cores from 13 drilled wells, four depositional facies have been interpreted: (1) fine-grained massive sandstone with floating mudstone clasts and planar clast fabric (sandy debrite); (2) fine-grained sandstone and siltstone showing contorted bedding, sand injection, and ptygmatic folding (sandy slump), (3) fine-grained sandstone with thin layers of normal grading and flute casts (turbidite), and (4) mudstone with faint laminae (suspension fallout). Combined with multiple seismic attributes, two depositional models are characterized by (1) sublacustrine fan: thick turbidite units occur at the bottom of the western sag beneath a series of normal faults slope. (2) Thinner deposition of sandy debrites mainly distribute at the bottom of eastern sag far from sandy slump at the lake margin slope, which interpreted to be controlled by "two-step" flexure slope break. The transfer zone located in the centre area is confirmed to be the primary origin for such differential depositions. In our study area, sandy debrites constitute the producing petroleum reservoirs, but turbidites are non reservoirs. This dramatic understanding will well account for "eastern much more than western" distribution of proven petroleum reserves and be applicable to predicting reservoir distribution.

Li, Y.; Chen, G.

2013-12-01

286

Mars Hand Lens Imager (MAHLI) Efforts and Observations at the Rocknest Eolian Sand Shadow in Curiosity's Gale Crater Field Site  

NASA Technical Reports Server (NTRS)

The Mars Science Laboratory (MSL) mission is focused on assessing the past or present habitability of Mars, through interrogation of environment and environmental records at the Curiosity rover field site in Gale crater. The MSL team has two methods available to collect, process and deliver samples to onboard analytical laboratories, the Chemistry and Mineralogy instrument (CheMin) and the Sample Analysis at Mars (SAM) instrument suite. One approach obtains samples by drilling into a rock, the other uses a scoop to collect loose regolith fines. Scooping was planned to be first method performed on Mars because materials could be readily scooped multiple times and used to remove any remaining, minute terrestrial contaminants from the sample processing system, the Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA). Because of this cleaning effort, the ideal first material to be scooped would consist of fine to very fine sand, like the interior of the Serpent Dune studied by the Mars Exploration Rover (MER) Spirit team in 2004 [1]. The MSL team selected a linear eolian deposit in the lee of a group of cobbles they named Rocknest (Fig. 1) as likely to be similar to Serpent Dune. Following the definitions in Chapter 13 of Bagnold [2], the deposit is termed a sand shadow. The scooping campaign occurred over approximately 6 weeks in October and November 2012. To support these activities, the Mars Hand Lens Imager (MAHLI) acquired images for engineering support/assessment and scientific inquiry.

Edgett, K. S.; Yingst, R. A.; Minitti, M. E.; Goetz, W.; Kah, L. C.; Kennedy, M. R.; Lipkaman, L. J.; Jensen, E. H.; Anderson, R. C.; Beegle, L. W.; Carsten, J. L.; Cooper, B.; Deen, R. G.; Dromart, G.; Eigenbrode, J. L.; Grotzinger, J. P.; Gupta, S.; Hamilton, V. E.; Hardgrove, C. J.; Harker, D. E.; Herkenhoff, K. E.; Herrera, P. N.; Hurowitz, J. A.; Jandura, L.; Ming, D. W.

2013-01-01

287

Policy Analysis of the Canadian Oil Sands Experience  

SciTech Connect

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.

None, None

2013-09-01

288

A Biopersistence Study following Exposure to Chrysotile Asbestos Alone or in Combination with Fine Particles  

PubMed Central

In designing a study to evaluate the inhalation biopersistence of a chrysotile asbestos that was used as a component of a joint-compound, a feasibility study was initiated to evaluate the short-term biopersistence of the chrysotile alone and of the chrysotile in combination witht the sanded reformulated joint-compound. Two groups of Wistar rats were exposed to either 7RF3 chrysotile (Group 2) or to 7RF3 chrysotile combined with aerosolized sanded joint-compound (Group 3). In addition, a control group was exposed to flltered-air. The chrysotile used in the Ready Mix joint compound is rapidly removed from the lung. The chrysotile alone exposure group had a clearance half-time of fibers L > 20 ?m of 2.2 days; in the chrysotile plus sanded exposure group the clearance half-time of fibers L > 20 ?m was 2.8 days. However, across all size ranges there was approximately an order of magnitude decrease in the mean number of fibers remaining in the lungs of Group 3 as compared to Group 2 despite similiar aerosol exposures. Histopathological examination showed that the chrysotile exposed lungs had the same appearance as the flltered-air controls. This study uniquely illustrates that additional concurrent exposure to an aerosol of the sanded joint-compound, with large numbers of fine-particles depositing in the lungs, accelerates the recruitment of macrophages, resulting in a tenfold decrease in the number of fibers remaining in the lung. The increased number of macrophages in the chrysotile/sanded joint exposure group was confirmed histologically, with this being the only exposure-related histological finding reported. PMID:18788018

Bernstein, D. M.; Donaldson, K.; Decker, U.; Gaering, S.; Kunzendorf, P.; Chevalier, J.; Holm, S. E.

2008-01-01

289

Virginia Museum of Fine Arts  

NSDL National Science Digital Library

The Virginia Museum of Fine Arts (VMFA) is a state-supported, privately endowed educational institution created for the benefit of the citizens of the Commonwealth of Virginia. Its purpose is "to collect, preserve, exhibit, and interpret art, to encourage the study of the arts, and thus to enrich the lives of all." The siteâ≢s homepage provides a variety of resources to experience the rich array of the VMFA's holdings and programs. In the Collections area, visitors can look through representative examples of their items from the ancient world, Africa, ancient American art, and twelve other areas. In the Learn area, visitors can take advantage of online art tutorials and learn about VMFA programs throughout Virginia. The Exhibitions area contains links to a range of images and printed materials that relate the stories of their current, past, and upcoming exhibits, such as "Indian Silver for the Raj" and "Say What? How Ancient Writing Began."

290

Oil shale, tar sands, and related materials  

SciTech Connect

This sixteen-chapter book focuses on the many problems and the new methodology associated with the commercialization of the oil shale and tar sand industry. Topics discussed include: an overview of the Department of Energy's oil shale R, D, and D program; computer simulation of explosive fracture of oil shale; fracturing of oil shale by treatment with liquid sulfur dioxide; chemistry of shale oil cracking; hydrogen sulfide evolution from Colorado oil shale; a possible mechanism of alkene/alkane production in oil shale retorting; oil shale retorting kinetics; kinetics of oil shale char gasification; a comparison of asphaltenes from naturally occurring shale bitumen and retorted shale oils: the influence of temperature on asphaltene structure; beneficiation of Green River oil shale by density methods; beneficiation of Green River oil shale pelletization; shell pellet heat exchange retorting: the SPHER energy-efficient process for retorting oil shale; retorted oil shale disposal research; an investigation into the potential economics of large-scale shale oil production; commercial scale refining of Paraho crude shale oil into military specification fuels; relation between fuel properties and chemical composition; chemical characterization/physical properties of US Navy shale-II fuels; relation between fuel properties and chemical composition: stability of oil shale-derived jet fuel; pyrolysis of shale oil residual fractions; synfuel stability: degradation mechanisms and actual findings; the chemistry of shale oil and its refined products; the reactivity of Cold Lake asphaltenes; influence of thermal processing on the properties of Cold Lake asphaltenes: the effect of distillation; thermal recovery of oil from tar sands by an energy-efficient process; and hydropyrolysis: the potential for primary upgrading of tar sand bitumen.

Stauffer, H.C.

1981-01-01

291

Aeolian Sand Transport with Collisional Suspension  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

292

Heating tar sands formations to visbreaking temperatures  

DOEpatents

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

Karanikas, John Michael (Houston, TX); Colmenares, Tulio Rafael (Houston, TX); Zhang, Etuan (Houston, TX); Marino, Marian (Houston, TX); Roes, Augustinus Wilhelmus Maria (Houston, TX); Ryan, Robert Charles (Houston, TX); Beer, Gary Lee (Houston, TX); Dombrowski, Robert James (Houston, TX); Jaiswal, Namit (Houston, TX)

2009-12-22

293

Heating tar sands formations while controlling pressure  

DOEpatents

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

Stegemeier, George Leo (Houston, TX) [Houston, TX; Beer, Gary Lee (Houston, TX) [Houston, TX; Zhang, Etuan (Houston, TX) [Houston, TX

2010-01-12

294

Dune Sand Fixation: Mauritania Seawater Pipeline Macroproject  

Microsoft Academic Search

\\u000a Wide-spreading actively migratory sand dune fields are mainly found in the Earth’s climatically designated desert regions—“hot\\u000a deserts” cover ~14.2% of Earth’s land (Peel et al. 2007; Parsons and Abrahams 2009). Some eremologists suspect that “global desertification”, a persistent decline of ecosystems’ benefits for humans—loss of\\u000a utility or potential utility of land—in already dry regions, is occurring and will increase as

Viorel Badescu; Richard B. Cathcart

295

Biogenic crust dynamics on sand dunes.  

PubMed

Sand dunes are often covered by vegetation and biogenic crusts. Despite their significant role in dune stabilization, biogenic crusts have rarely been considered in model studies of dune dynamics. Using a simple model, we study the existence and stability ranges of different dune-cover states along gradients of rainfall and wind power. Two ranges of alternative stable states are identified: fixed crusted dunes and fixed vegetated dunes at low wind power; and fixed vegetated dunes and active dunes at high wind power. These results suggest a crossover between two different forms of desertification. PMID:23496449

Kinast, Shai; Meron, Ehud; Yizhaq, Hezi; Ashkenazy, Yosef

2013-02-01

296

Technology of Sand Level Detection Based on CCD Images  

NASA Astrophysics Data System (ADS)

Heavy oil takes advantage of proportion in world petroleum resources. Thermal recovery technology, the chief means of heavy-oil exploitation, has been widely applied in development of world heavy-oil reservoir. To study the effect of sand-control technology in the process of heavy-oil thermal recovery, A HTRSTS (Heavy-oil Thermal Recovery Simulation Testing System) has been build. The detection of sand level in sand container is very important. The sand level detection technology adopted in this system is image processing technique based on CCD. Sand container image is taken by CCD, and then HTRSTS locks the interface between sand and liquid through CCD scanning. The preliminary experimental result shows that the standard deviation is about 0.02 liter, which could satisfy practical requirement quite well.

Jiang, Bing; Li, Xianglin; Chen, Xiaohui; Zhang, Tengfei; Feng, Chi; Zhang, Fei

297

Biogenic and anthropogenic organic components of Saharan sands.  

PubMed

Till now, the Sahara desert sands have scarcely characterized for their organic contents, despite they are known to heavily affect Europe and America when transported by winds. In this study, the composition of sands collected in ten oasis lying in two regions of the Algerian Sahara during 2011 was investigated with regards to organic fraction. Attention was paid to anthropogenic and biogenic sources of organics associated to sands, through the characterization of n-alkanes, n-alkanoic and n-alkanedioic acids, n-alkanols, sterols, PAHs and caffeine. The organic fraction load on sands associable to natural sources was higher in the Region of Biskra than in that of Ouargla. The biogenic contribution to the total amount of organics in sands exceeded that of the anthropogenic sources. The composition of sands from Hassi Messaoud, compared to that observed there in 2006, showed that the anthropic impact over the region was not changed. PMID:24875880

Balducci, Catia; Ladji, Riad; Muto, Valeria; Romagnoli, Paola; Yassaa, Nourredine; Cecinato, Angelo

2014-07-01

298

Impact on demersal fish of a large-scale and deep sand extraction site with ecosystem-based landscaped sandbars  

NASA Astrophysics Data System (ADS)

For the seaward harbour extension of the Port of Rotterdam in the Netherlands, approximately 220 million m3 sand was extracted between 2009 and 2013. In order to decrease the surface area of direct impact, the authorities permitted deep sand extraction, down to 20 m below the seabed. Biological and physical impacts of large-scale and deep sand extraction are still being investigated and largely unknown. For this reason, we investigated the colonization of demersal fish in a deep sand extraction site. Two sandbars were artificially created by selective dredging, copying naturally occurring meso-scale bedforms to increase habitat heterogeneity and increasing post-dredging benthic and demersal fish species richness and biomass. Significant differences in demersal fish species assemblages in the sand extraction site were associated with variables such as water depth, median grain size, fraction of very fine sand, biomass of white furrow shell (Abra alba) and time after the cessation of sand extraction. Large quantities of undigested crushed white furrow shell fragments were found in all stomachs and intestines of plaice (Pleuronectes platessa), indicating that it is an important prey item. One and two years after cessation, a significant 20-fold increase in demersal fish biomass was observed in deep parts of the extraction site. In the troughs of a landscaped sandbar however, a significant drop in biomass down to reference levels and a significant change in species assemblage was observed two years after cessation. The fish assemblage at the crests of the sandbars differed significantly from the troughs with tub gurnard (Chelidonichthys lucerna) being a Dufrêne-Legendre indicator species of the crests. This is a first indication of the applicability of landscaping techniques to induce heterogeneity of the seabed although it remains difficult to draw a strong conclusion due the lack of replication in the experiment. A new ecological equilibrium is not reached after 2 years since biotic and abiotic variables are still adapting. To understand the final impact of deep and large-scale sand extraction on demersal fish, we recommend monitoring for a longer period, at least for a period of six years or even longer.

de Jong, Maarten F.; Baptist, Martin J.; van Hal, Ralf; de Boois, Ingeborg J.; Lindeboom, Han J.; Hoekstra, Piet

2014-06-01

299

Process for the production of fine chemicals  

US Patent & Trademark Office Database

The present invention relates to a process for the production of fine chemicals in a microorganism, a plant cell, a plant, a plant tissue or parts thereof by increasing or generating the biological activity of a ras-Like GTPase or the homologues thereof and growing the organism under conditions which permit the production of the fine chemicals in the organism. Preferred fine chemicals produced by the present invention include amino acids, carbohydrates, vitamins, fatty acids, and carotenoids.

2011-08-30

300

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

NASA Astrophysics Data System (ADS)

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

Turner, Brian R.; Smith, Denys B.

1997-12-01

301

Final report on Thermally Modified Sand demonstration project  

SciTech Connect

The use of salt and salt/sand mixtures on icy roadway surfaces has dramatically increased during the past 30 years. Despite extensive documentation on salt related damage to the roadway improvements, vehicles and the environment, road maintenance departments have continued to rely on this practice. Road maintenance departments in northern climate areas have long recognized the safety benefits for public mobility on icy roadways from the use of sand. As an abrasive material, the sand improves the surface traction that results in more drivable and less hazardous road conditions during the winter months. Stockpiles of pure sand stored during the winter months oftentimes freeze into large unworkable, monolithic piles. To maintain a free-flowing condition, it has been found to be necessary to add salt to the sand. The addition of salt in amounts ranging from 5 to 10 percent to that of sand, is usually sufficient to provide relatively free-flowing abrasive material that could be stored in stockpiles and applied to icy road surfaces with conventional sand spreading trucks. Another alternative for winter storage of pure sand to maintain a free-flowing condition is in humidity-controlled, heated buildings. As would be expected, this method has high capital and operating costs. and not cost effective for general highway maintenance use. The invention demonstrated herein is a method of thermally modifying pure sand that will remain in a free-flowing state throughout the winter season without the need for the salt additive. The thermally modified sand provides an abrasive material that when applied to icy roads does not cause environmental and corrosive damage as done by the application of sand with salt. By employing a very simple process of freezing screened sand particles by forced air convection under subfreezing conditions, the invention creates a product that has significant value in terms of economic and environmental benefits.

Not Available

1994-09-23

302

Have the northwest Negev dunefield sands reddened since their deposition?  

Microsoft Academic Search

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

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

2010-01-01

303

Parasite infection and sand coarseness increase sand crab (Emerita analoga) burrowing time.  

PubMed

Parasites with indirect life cycles require trophic transmission from intermediate hosts to definitive (vertebrate) hosts. Transmission may be facilitated if parasite infection alters the behavior of intermediate hosts such that they are more vulnerable to predation. Vulnerability to predation may also be influenced by abiotic factors; however, rarely are the effects of parasites and abiotic factors examined simultaneously. The swash zone of sandy beaches is a particularly harsh environment. Sand crabs (Emerita analoga) burrow rapidly in the swash zone to avoid predators and dislodgment. We examined prevalence and abundance of the acanthocephalan parasite Profilicollis altmani in sand crabs, and investigated the synergistic effects of sand grain size (an important abiotic factor), parasite infection, body size and reproductive condition on burrowing speed in females, from three California sites. More heavily parasitized crabs burrowed more slowly, making them potentially more vulnerable to predation by marine bird definitive hosts. Ovigerous females harbored more parasites than non-ovigerous females, but burrowed more quickly. All crabs burrowed slowest in the coarsest sand, and burrowing times increased with repeated testing, suggesting that it is energetically costly. Abiotic and biotic factors influence burrowing, and behavioral variation across sites may reflect the response to natural variation in these factors. PMID:21959036

Kolluru, Gita R; Green, Zachary S; Vredevoe, Larisa K; Kuzma, Matthew R; Ramadan, Sera N; Zosky, Marc R

2011-11-01

304

TRANSPORT OF MACROMOLECULES AND HUMATE COLLOIDS THROUGH A SAND AND A CLAY AMENDED SAND LABORATORY COLUMN  

EPA Science Inventory

Laboratory experiments were conducted to determine if macromolecules or humate colloids would transport through sand columns and if they would exhibit any variations in their relative velocity based upon their molecular volumes and the pore size distribution of the column packing...

305

Fused silica fine grinding with low roughness  

NASA Astrophysics Data System (ADS)

Lithography-optics is one of the most complex optical systems. The fine grinding process is the most important step before polishing. Roughness and sub-surface damage (SSD) are essential outputs of fine grinding. We demonstrate the method that use fix abrasive cup tool with CNC grinding machine to complete the fine grinding process, even instead of lapping process. And experiment sample roughness can reach 23.40nm rms and Ra 18.554nm. The SSD estimate is about 2 ?m which is also smaller than commercial lapping process. The fine grinding output can satisfy the lithography optic fabrication demands and efficiently reduce the polishing time.

Dai, Lei; Gu, Yongqiang; Wu, Di

2014-08-01

306

Reuse of waste cutting sand at Lawrence Livermore National Laboratory  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) examined the waste stream from a water jet cutting operation, to evaluate the possible reuse of waste garnet sand. The sand is a cutting agent used to shape a variety of materials, including metals. Nearly 70,000 pounds of waste sand is generated annually by the cutting operation. The Environmental Protection Department evaluated two potential reuses for the spent garnet sand: backfill in utility trenches; and as a concrete constituent. In both applications, garnet waste would replace the sand formerly purchases by LLNL for these purposes. Findings supported the reuse of waste garnet sand in concrete, but disqualified its proposed application as trench backfill. Waste sand stabilized in ac concrete matrix appeared to present no metals-leaching hazard; however, unconsolidated sand in trenches could potentially leach metals in concentrations high enough to threaten ground water quality. A technical report submitted to the San Francisco Bay Regional Water Quality Control Board was reviewed and accepted by that body. Reuse of waste garnet cutting sand as a constituent in concrete poured to form walkways and patios at LLNL was approved.

Mathews, S., LLNL

1998-02-25

307

Microbes in beach sands: integrating environment, ecology and public health  

E-print Network

- logical factors, such as competition, predation, and biofilm formation; and nutrient availability all evidence of health risks associated with sand exposure. Persistent or replicating populations of FIB

Lajeunesse, Marc J.

308

CIR sand casting system for trans-tibial socket.  

PubMed

The authors have developed a trans-tibial socket fabrication system based on the "dilatancy" principle, a process that has been commonly used in forming wheelchair Seating. The CIR Sand Casting System replaces plaster of Paris with sand for forming both a negative sand mould and a positive sand model, which can be modified for either thermoplastic socket formation or resin lamination. Initial clinical trials suggest that fabrication times are approximately 90 minutes from patient evaluation and casting to dynamic alignment. Compatibility with all existing prosthetic components is retained. It is believed the CIR socket fabrication system may be a competitive alternative for prosthetic service providers in developing countries. PMID:14571945

Wu, Y; Casanova, H; Smith, W K; Edwards, M; Childress, D S

2003-08-01

309

Direct numerical simulations of aeolian sand ripples  

E-print Network

Aeolian sand beds exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns out to be driven by resonant grain trajectories, whose length is close to a ripple wavelength and whose splash leads to a mass displacement towards the ripple crests. The pattern selection results from a compromise between this destabilizing mechanism and a diffusive downslope transport which stabilizes small wavelengths. The initial wavelength is set by the ratio of the sediment flux and the erosion/deposition rate, a ratio which increases linearly with the wind velocity. We show that this scaling law, in agreement with experiments, originates from an interfacial layer separating the saltation zone from the static sand bed, where momentum transfers are dominated by mid-air collisions. Finally, we provide quantitative support for the use the propagation of these ripples as a proxy for remote measurements of sediment transport.

Orencio Duran; Philippe Claudin; Bruno Andreotti

2014-11-07

310

Soggy-sand electrolytes: status and perspectives.  

PubMed

Soggy-sand electrolytes (solid-liquid composites, typically gel electrolytes, with synergistic electrical properties) are reviewed as far as status and perspectives are concerned. Major emphasis is put on the understanding of the local mechanism as well as the long-range transport along the filler network. The beneficial property spectrum includes enhanced conductivity of one ion type and decreased conductivity of the counter ion, but also the exciting mechanical properties of the solid-liquid composites. Inherent but not insurmountable problems lie in the reproducibility and stationarity of the composites microstructure and morphology. Owing to the huge parameter complexity and hence to the multitude of adjusting screws, there are various strategies for materials optimization. The technological relevance is enormous, in particular for battery electrolytes as here all the above-mentioned electrical and mechanical benefits are welcome. The soggy-sand electrolytes combine high Li(+) conductivity, low anion conductivity and good wettability of electrode particles with the mechanical stability of semi-solids. PMID:24080900

Pfaffenhuber, C; Göbel, M; Popovic, J; Maier, J

2013-11-14

311

Yield stress transition in gas fluidized sand.  

NASA Astrophysics Data System (ADS)

Gas fluidized powders can take on three distinct states. I: Solid like for low gas flow rates. II: At intermediate flow rates, the bed expands and drastically reduces its yield stress, i.e. quicksand which cannot support the weight of solid objects. III: At high flow rates rising gas bubbles churn the sand grains violently. We have measured that the transition from regime I to II does not occur simultaneously for the entire column, but rather as a well defined front which sweeps through the column as a function of gas flow rate. Earlier measurements sensed this front by measuring the depth to which a brass sphere would sink in the liquid phase. We have supplemented this with careful measurements of the vertical gas pressure gradient throughout the column. The pressure profile shows a distinct change in the gradient at a height which correlates well with results from the sinking sphere measurement. From the pressure gradient we calculate the local gas permeability of the sand, which is related to the grain density, which can be measured with an accuracy of better than 1 part in 100. We thank the NSF-REU program for partial support of this research.

Stoker, David; Poker, Jennifer; Savrin, Tamara; Rutgers, Maarten

2000-11-01

312

Direct numerical simulations of aeolian sand ripples.  

PubMed

Aeolian sand beds exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns out to be driven by resonant grain trajectories, whose length is close to a ripple wavelength and whose splash leads to a mass displacement toward the ripple crests. The pattern selection results from a compromise between this destabilizing mechanism and a diffusive downslope transport which stabilizes small wavelengths. The initial wavelength is set by the ratio of the sediment flux and the erosion/deposition rate, a ratio which increases linearly with the wind velocity. We show that this scaling law, in agreement with experiments, originates from an interfacial layer separating the saltation zone from the static sand bed, where momentum transfers are dominated by midair collisions. Finally, we provide quantitative support for the use of the propagation of these ripples as a proxy for remote measurements of sediment transport. PMID:25331873

Durán, Orencio; Claudin, Philippe; Andreotti, Bruno

2014-11-01

313

Avalanches of Singing Sand in the Laboratory  

NASA Astrophysics Data System (ADS)

The song of dunes is a natural phenomenon that has arisen travellers' curiosity for a long time, from Marco Polo to R.A. Bagnold. Scientific observations in the XXth century have shown that the sound is emitted during a shear flow of these particular grains, the free surface of the flow having coherent vibrations like a loud speaker. The sound emission is also submitted to a threshold effect with many parameters like humidity, flow speed, surface of the grains. The sound has been reproduced in laboratory avalanche experiments close to the natural phenomenon on field, but set in a channel with a hard bottom and a few centimeters of sand flowing, which contradicts explanations of the sound that involve a sand dune under the avalanche flow. Flow rates measurements also show the presence of a plug region in the flow above the sheared band, with the same characteristic length as the coherence zones of the sound. Finally we show experimentally that the Froude number, once modified to take into account the height of this plug band, is the parameter that sets the amplitude of the sound, and produces a threshold that depends on the grain type.

Dagois-Bohy, Simon; Courrech Du Pont, Sylvain; Douady, Stéphane

2011-03-01

314

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

USGS Publications Warehouse

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 by minimizing in-channel sediment storage on the alluvial fans. The post-development annual sediment yield to the Whitewater and Mission Creek?Morongo Wash depositional areas are 3.5 and 1.5 million ft3/yr, respectively, covering each depositional area to a depth of 0.2 to 0.4 in. Given existing sand-transport rates, this material could be depleted by eolian processes in 8 to 16 months, a rate consistent with the presence of persistent sand dunes. However, these depletion times are likely minimum estimates, as some eolian sand is seen to persist in the immediate vicinity of depositional areas for longer time periods. Transport rates may be reduced by the presence of vegetation and other windbreaks. Because they are perpendicular to prevailing winds, the infiltration galleries on Whitewater River trap fluvial and eolian sediment, reducing sediment availability. Also, the presence of the railroad and Interstate 10 redirect eolian sand movement to the southeast along their corridors,potentially eliminating the Whitewater depositional area as a sand source for the Willow Hole Reserve. Using directional wind data, we discuss the potential for eolian sand transport from the Mission Creek?Morongo Wash depositional area to Willow Hole.

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

2002-01-01

315

Activity of Wind-Blown Sand and the Formation of Feathered Sand Ridges in the Kumtagh Desert, China  

Microsoft Academic Search

We study the activity of wind-blown sand and its effects on the evolution of feathered sand ridges in the Kumtagh Desert,\\u000a China, and attempt to reveal the formation process of feathered sand ridges using wind-tunnel experiments, remote sensing\\u000a data, and detailed field observations from 2005 to 2008. The prevailing wind direction in the Kumtagh Desert is easterly in\\u000a winter and

Kongtai Liao; Jianjun Qu; Jinnian Tang; Feng Ding; Hujun Liu; Shujuan Zhu

2010-01-01

316

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

NASA Astrophysics Data System (ADS)

Glen Canyon Dam has caused a fundamental change in the distribution of fine sediment storage in the 99-km reach of the Colorado River in Marble Canyon, Grand Canyon National Park, Arizona. The two major storage sites for fine sediment (i.e., sand and finer material) in this canyon river are lateral recirculation eddies and the main-channel bed. We use a combination of methods, including direct measurement of sediment storage change, measurements of sediment flux, and comparison of the grain size of sediment found in different storage sites relative to the supply and that in transport, in order to evaluate the change in both the volume and location of sediment storage. The analysis shows that the bed of the main channel was an important storage environment for fine sediment in the predam era. In years of large seasonal accumulation, approximately 50% of the fine sediment supplied to the reach from upstream sources was stored on the main-channel bed. In contrast, sediment budgets constructed for two short-duration, high experimental releases from Glen Canyon Dam indicate that approximately 90% of the sediment discharge from the reach during each release was derived from eddy storage, rather than from sandy deposits on the main-channel bed. These results indicate that the majority of the fine sediment in Marble Canyon is now stored in eddies, even though they occupy a small percentage (˜17%) of the total river area. Because of a 95% reduction in the supply of fine sediment to Marble Canyon, future high releases without significant input of tributary sediment will potentially erode sediment from long-term eddy storage, resulting in continued degradation in Marble Canyon.

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

2006-03-01

317

Faecal indicator bacteria enumeration in beach sand: A comparison study of extraction methods in medium to coarse sands  

USGS Publications Warehouse

Aims: The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique. Methods and Results: Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. Conclusions: The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. Significance and Impact of the Study: Method standardization will improve the understanding of how sands affect surface water quality. ?? 2009 The Society for Applied Microbiology.

Boehm, A. B.; Griffith, J.; McGee, C.; Edge, T. A.; Solo-Gabriele, H. M.; Whitman, R.; Cao, Y.; Getrich, M.; Jay, J. A.; Ferguson, D.; Goodwin, K. D.; Lee, C. M.; Madison, M.; Weisberg, S. B.

2009-01-01

318

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

Microsoft Academic Search

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

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

1985-01-01

319

Portland State University Fines and Fees Process  

E-print Network

to the students Materials that must conform to certain specification and be identical for all students Expensive of the university planning office to determine if there is a possible conflict with public vs. private use o by an authorized individual and approved by the dean/designee during annual fines and fees process · Fines and fees

Caughman, John

320

ADVANCING FINE ROOT RESEARCH WITH MINIRHIZOTRONS  

EPA Science Inventory

Minirhizotrons provide a nondestructive, in situ method for directly viewing and studying fine roots. Although many insights into fine roots have been gained using minirhizotrons, it is clear from the literature that there is still wide variation in how minirhizotrons and minirhi...

321

Fine Aggregate Angularity from Geotechnical Perspective  

Microsoft Academic Search

Particle angularity is an important aspect in the performance of asphalt concrete pavements. When rounded materials are used, the shear strength is reduced resulting in rutting and shoving of the asphalt concrete mixtures. Currently, the Superpave design method stipulates that the fine aggregate angularity (FAA) via AASHTO T304 be used as a test specification for fine aggregate. The objectives of

Stan Vitton; Jason P. Bausano; R. Christopher Williams; Vernon Schafer

2008-01-01

322

FINE P M EMISSIONS CHARACTERIZATION--BIOMASS  

EPA Science Inventory

FINE PM EMISSIONS CHARACTERIZATION -- BIOMASS The APPCD fine particle research team was funded (FY 2000) to perform emission characterization and source chemical profile analysis of major particle source emissions in the U.S. The focus of this task is to analyze these data on ai...

323

Curiosity at Gale crater, Mars: characterization and analysis of the Rocknest sand shadow.  

PubMed

The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MERs) Spirit and Opportunity. The fraction of sand <150 micrometers in size contains ~55% crystalline material consistent with a basaltic heritage and ~45% x-ray amorphous material. The amorphous component of Rocknest is iron-rich and silicon-poor and is the host of the volatiles (water, oxygen, sulfur dioxide, carbon dioxide, and chlorine) detected by the Sample Analysis at Mars instrument and of the fine-grained nanophase oxide component first described from basaltic soils analyzed by MERs. The similarity between soils and aeolian materials analyzed at Gusev Crater, Meridiani Planum, and Gale Crater implies locally sourced, globally similar basaltic materials or globally and regionally sourced basaltic components deposited locally at all three locations. PMID:24072928

Blake, D F; Morris, R V; Kocurek, G; Morrison, S M; Downs, R T; Bish, D; Ming, D W; Edgett, K S; Rubin, D; Goetz, W; Madsen, M B; Sullivan, R; Gellert, R; Campbell, I; Treiman, A H; McLennan, S M; Yen, A S; Grotzinger, J; Vaniman, D T; Chipera, S J; Achilles, C N; Rampe, E B; Sumner, D; Meslin, P-Y; Maurice, S; Forni, O; Gasnault, O; Fisk, M; Schmidt, M; Mahaffy, P; Leshin, L A; Glavin, D; Steele, A; Freissinet, C; Navarro-González, R; Yingst, R A; Kah, L C; Bridges, N; Lewis, K W; Bristow, T F; Farmer, J D; Crisp, J A; Stolper, E M; Des Marais, D J; Sarrazin, P

2013-09-27

324

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

Microsoft Academic Search

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

H. C. Olson

1986-01-01

325

Major tar sand and heavy oil deposits of the US  

Microsoft Academic Search

The need for this report has grown with each passing year since the last official tabulation of US tar sands, the 1965 Department of Interior\\/Bureau of Mines Monograph 12 entitled, Surface and Shallow Oil-Impregnated Rocks of the United States. Four important national energy resource objectives are addressed: (1) to develop an updated assessment of US tar sand resources; (2) to

Hammershaimb

1983-01-01

326

Oil shale and tar sands as substitute fuels  

Microsoft Academic Search

From the sheer magnitude of the resources available, coal takes a strong position as the alternate source of fuel supplies when petroleum is unavailable. However oil shale and tar sands are also possibilities, and, indeed, have some advantages over coal. Although Oklahoma has no oil shale deposits, it does have appreciable amounts of tar sands. Oil shale deposits in the

Ball

1974-01-01

327

Completion methods in thick, multilayered tight gas sands  

E-print Network

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

Ogueri, Obinna Stavely

2009-05-15

328

Completion methods in thick, multilayered tight gas sands  

E-print Network

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

Ogueri, Obinna Stavely

2008-10-10

329

www.nasa.gov WHITE SANDS MISSILE RANGE ACCESS CAPABILITIES  

E-print Network

www.nasa.gov WHITE SANDS MISSILE RANGE ACCESS CAPABILITIES SUMMARY White Sands Test Facility (WSTF Missile Range (WSMR). EXPERIENCE WSTF works with WSMR in support of customer needs and test activities and missile launch, tracking, and recovery · Nuclear effects testing · High-speed sled track · Directed energy

330

Spatial variability of flow parameters in a stratified sand  

Microsoft Academic Search

The spatial variability in porosity, hydraulic conductivity, compressibility, and various grain size fractions is analyzed for several sets of samples from the Quadra Sand. This unit is a well-sorted, medium grained, horizontally stratified sand with relatively few silt or gravel interbeds. Both random and uniformly spaced sample plans are used. The heterogeneity of the flow parameters is characterized by frequency

Leslie Smith

1981-01-01

331

Coastal Sand Dune Plant Ecology: Field Phenomena and Interpretation  

ERIC Educational Resources Information Center

Discusses the advantages and disadvantages of selecting coastal sand dunes as the location for field ecology studies. Presents a descriptive zonal model for seaboard sand dune plant communities, suggestions concerning possible observations and activities relevant to interpreting phenomena associated with these forms of vegetation, and additional…

McDonald, K.

1973-01-01

332

Household scale slow sand filtration in the Dominican Republic  

E-print Network

Slow sand filtration is a method of water treatment that has been used for hundreds of years. In the past two decades, there has been resurgence in interest in slow sand filtration, particularly as a low-cost, household-scale ...

Donison, Kori S. (Kori Shay), 1981-

2004-01-01

333

Numerical Modeling of Hydraulic Fracturing in Oil Sands  

E-print Network

`Oil sands' exist in some parts of the world as thick deposits .... Settari and Raisbeck [10,11] provided two of the early work ...... is kept equal to zero at the top surface; everywhere else, ..... Lane Mountain sand grain was determined to be 2.65.

2008-11-16

334

Sand filtration. (Latest citations from Pollution Abstracts). Published Search  

SciTech Connect

The bibliography contains citations concerning the design and applications of sand filtration for water and wastewater purification. Applications include purification of drinking water and catchment water, as well as sewage treatment and wastewater reclamation. Mathematical models of sand filters are also presented. (Contains a minimum of 175 citations and includes a subject term index and title list.)

Not Available

1992-06-01

335

Bulk engineering and durability properties of washed glass sand concrete  

Microsoft Academic Search

The paper reports the results of an experimental programme aimed at examining the performance of Portland-cement concrete produced with washed glass sand (WGS), as natural sand substitute- by mass. The effects of up to 50% WGS on fresh, engineering and durability related properties have been established and its suitability for use in a range of normal-grade concrete production assessed. WGS

Mukesh C. Limbachiya

2009-01-01

336

SLOW SAND FILTER MAINTENANCE COSTS AND EFFECTS ON WATER QUALITY  

EPA Science Inventory

A study was conducted to determine how slow sand filter effluent quality is affected by scraping and to quantify the labor required to operate and maintain a slow sand filter. The data were obtained by monitoring scraping and other maintenance operations at six full-size slow san...

337

A finite element analysis of pneumatic-tire/sand interactions  

E-print Network

A finite element analysis of pneumatic-tire/sand interactions during off-road vehicle travel M to investigate the interactions between a stereotypical pneumatic tire and sand during off-road vehicle travel. Different components of the pneumatic tire were modeled using elastic, hyper- and visco-elastic material

Grujicic, Mica

338

Productivity and equipment selection in surface mining of oil sands  

Microsoft Academic Search

A variety of mining equipment is used in the mining of oil sands by surface mining. This includes bucket wheel excavators, draglines, hydraulic shovels and off-highway trucks. This paper examines the existing mining schemes and equipment used. Peculiarities of oil sands surface mining and their influence on equipment selection, utilization and mining schemes are described. Recent developments undertaken to improve

R. K. Singhal; R. J. Kolada; T. I. Vladut

1985-01-01

339

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

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

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

340

BLAISDELL SLOW SAND FILTER WASHING MACHINE. VIEW LOOKING NORTHWEST. PIPING ...  

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

BLAISDELL SLOW SAND FILTER WASHING MACHINE. VIEW LOOKING NORTHWEST. PIPING IN FOREGROUND IS NOT RELATED TO THE MACHINE. THE NORTHEAST CORNER OF SETTLING RESERVOIR NO. 3 IS SEEN AT THE LOWER LEFT. - Yuma Main Street Water Treatment Plant, Blaisdell Slow Sand Filter Washing Machine, Jones Street at foot of Main Street, Yuma, Yuma County, AZ

341

Self-similar dynamic quasi-two-dimensional sand fronts  

Microsoft Academic Search

We report on a study of advancing quasi-two-dimensional sand fronts on an inclined flat and thin strip confined between two vertical plates. These fronts form when a thin initial stream of sand running down the flat obstacle gets trapped at some distance from the injection point. Right after this trapping, the front starts to advance upstream and grow in time.

J.-F. Boudet; S. Gauthier; Y. Amarouchene; H. Kellay

2003-01-01

342

7. SAND FILTERS, CANAL TO LEFT. CONCRETE OVERFLOW AREA TO ...  

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

7. SAND FILTERS, CANAL TO LEFT. CONCRETE OVERFLOW AREA TO LEFT OF CANAL ORIGINALLY PLANNED AS A STORAGE LAKE. VIEW LOOKING DUE WEST OF HINDS COMPLEX IN BACKGROUND OF SAND FILTERS. - Hinds Pump Plant, East of Joshua Tree National Monument, 5 miles north of Route 10, Hayfield, Riverside County, CA

343

31. PETIBONE SAND THROWING MACHINE BOX FLOOR GREY IRON FOUNDRY ...  

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

31. PETIBONE SAND THROWING MACHINE BOX FLOOR GREY IRON FOUNDRY FORCES CONDITIONED MOLDING SAND, AT HIGH VELOCITY, INTO MOLDS TOO BIG TO BE MADE ON ONE OF THE CONVEYOR SYSTEMS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

344

Modelling of reoxidation inclusion formation in steel sand casting  

E-print Network

Modelling of reoxidation inclusion formation in steel sand casting A. J. Melendez, K. D. Carlson pouring, as well as their final locations on the surface of steel sand castings. Inclusions originate. The inclusion model is implemented in a general-purpose casting simulation code. The model is validated

Beckermann, Christoph

345

Monitoring CO2 gas-phase injection in a shallow sand aquifer using cross borehole GPR  

NASA Astrophysics Data System (ADS)

An important issue that needs attention in designing effective storage schemes for CO2 storage in deep geologic formations is risk assessment of potential leakage. Leaking gas may threat surface and groundwater sources as well as vegetation. We have designed an experiment where we were track the movement of an injected CO2 gas-phase in an unconfined aquifer using cross borehole GPR. The test site is located in the south-western part of Denmark. The aquifer at the site consists of fine to coarse glacial melt water sands, which are staggered in slightly tilted layers. In all experiments gas was injected for 48 hours with flow rates between 9-16 g/min. The screen of the injection well is 10 m below ground level or 8 m below the water table. Initially an array of four GPR boreholes was installed around the injection well and subsequently two extra GPR Boreholes were installed downwards of dominating gas flow direction. GPR-data were acquired in zero offset (1D) and multiple offset (2D) configurations prior and during the injection. To support the GPR measurements 12 Decagon 5-TE soil moisture probes were installed at various dept for the last experiments. Both set of GPR data showed that a plume developed at the depth of the injection screen and that the injected gas primarily spread towards South-East. The geology consists of slightly tilting layers, which may cause migration of the gas plume along the interface of the coarse and fine sand and out of the monitoring area. The results confirmed the notion that geological heterogeneity has a critical impact on the gas migration pattern. The gas plume migration was further analysed by the multi-phase numerical code T2VOC a part of the TOUGH family.

Lassen, R. N.; Looms, M. C.; Jensen, K. H.; Sonnenborg, T.

2012-12-01

346

Evaluation of Instability Phenomena in Sands: Plane Strain Versus Triaxial Conditions  

NASA Technical Reports Server (NTRS)

Extensive research was carried out in the 1950s on theories of plasticity to extend the concepts developed for metals to materials that failed according to the Mohr-Coulomb criterion. The new ideas made it possible to merge the two distinct concepts (strength and deformation techniques) into one that relies on better understanding of plasticity and resulted in a rapid growth in the field of constitutive modeling of soil behavior. At the same time advanced experimental apparatuses and laboratory procedures were developed to calibrate the models. However, most laboratory experiments on granular materials are performed under Conventional Triaxial Conditions (CTC) for the purposes of evaluating constitutive behavior and stability properties, whereas most geotechnical field problems are closer to the Plane Strain (PS) condition. The triaxial tests performed in most laboratories comprise a simplification over in situ states and allow easier and robust experimentation. Most landslide problems, failure of soils beneath shallow and deep foundations, and failure of retaining structures, are cases that can generally be considered as plane strain. Strength and deformation characteristics of granular materials loaded in plane strain may be considerably different from those observed in CTC. Most studies on sands were limited to evaluating the constitutive behavior and in some cases extended to briefly describing the associated instability phenomena. This paper presents the results of a series of PS and CTC experiments performed on fine uniform silica sand known as F-75 Ottawa sand. Advanced analysis techniques were used to study the instability phenomena, which yielded very accurate measurements of shear bands occurrences and patterns. Destructive thin-sectioning technique along with monitoring the specimen surface deformation was used in the PS experiments and Computed Tomography (CT) was used to investigate the progress of primary and secondary shear bands in specimens subjected to CTC. Comparison between the two cases will be presented and discussed.

Alshibli, Khalid A.

2001-01-01

347

Reproductive development of yellow perch (Perca flavescens) exposed to oil sands-affected waters.  

PubMed

In similar experiments conducted in 1996 and 2009, yellow perch (Perca flavescens) were stocked into two experimental systems: a demonstration lake where oil sands fine tailings were capped with natural water and a lake in a watershed containing bitumen-bearing sodic clays. In both experiments, yellow perch were captured in May from a nearby reservoir and released into the experimental ponds. Perch were recaptured in the experimental systems, the source lake, and two reference lakes in late September and lethally sampled to examine reproductive parameters. In the 1996 experiment, gonad size and steroid hormones were not affected in either pond environment. In the 2009 experiment, male perch in the water-capped tailings pond showed a significant reduction in the testicular development and reductions in circulating testosterone and 11-ketotestosterone, while no reductions were seen in the second experimental pond. No changes were observed in ovarian size or circulating steroid levels in female perch. In the pond containing tailings, the release of water from underlying tailings caused approximately a twofold increase in salinity, alkalinity, and naphthenic acids, and a pH increase from 8.4 to 9.4 over the 13-year period of the study. In the pond influenced by unextracted oil sands materials, total dissolved solids, major ions, and pH did not change substantially. However, naphthenic acids in this system dropped more than twofold post-watershed reclamation. Because the selective reproductive effect observed in male perch in the experimental end-pit lake were accompanied by increases in naphthenic acids, alkalinity, and pH, a specific cause cannot be determined. The present study adds to the evidence, suggesting the presence of endocrine-disrupting substances in oil sands. PMID:22189895

Heuvel, Michael R van den; Hogan, Natacha S; Roloson, Scott D; Kraak, Glen J Van Der

2012-03-01

348

Microbially-accelerated consolidation of oil sands tailings. Pathway II: solid phase biogeochemistry  

PubMed Central

Consolidation of clay particles in aqueous tailings suspensions is a major obstacle to effective management of oil sands tailings ponds in northern Alberta, Canada. We have observed that microorganisms indigenous to the tailings ponds accelerate consolidation of mature fine tailings (MFT) during active metabolism by using two biogeochemical pathways. In Pathway I, microbes alter porewater chemistry to indirectly increase consolidation of MFT. Here, we describe Pathway II comprising significant, direct and complementary biogeochemical reactions with MFT mineral surfaces. An anaerobic microbial community comprising Bacteria (predominantly Clostridiales, Synergistaceae, and Desulfobulbaceae) and Archaea (Methanolinea/Methanoregula and Methanosaeta) transformed FeIII minerals in MFT to amorphous FeII minerals during methanogenic metabolism of an added organic substrate. Synchrotron analyses suggested that ferrihydrite (5Fe2O3. 9H2O) and goethite (?-FeOOH) were the dominant FeIII minerals in MFT. The formation of amorphous iron sulfide (FeS) and possibly green rust entrapped and masked electronegative clay surfaces in amended MFT. Both Pathways I and II reduced the surface charge potential (repulsive forces) of the clay particles in MFT, which aided aggregation of clays and formation of networks of pores, as visualized using cryo-scanning electron microscopy (SEM). These reactions facilitated the egress of porewater from MFT and increased consolidation of tailings solids. These results have large-scale implications for management and reclamation of oil sands tailings ponds, a burgeoning environmental issue for the public and government regulators. PMID:24711806

Siddique, Tariq; Kuznetsov, Petr; Kuznetsova, Alsu; Li, Carmen; Young, Rozlyn; Arocena, Joselito M.; Foght, Julia M.

2014-01-01

349

Power generation and oil sands process-affected water treatment in microbial fuel cells.  

PubMed

Oil sands process-affected water (OSPW), a product of bitumen isolation in the oil sands industry, is a source of pollution if not properly treated. In present study, OSPW treatment and voltage generation were examined in a single chamber air-cathode microbial fuel cell (MFC) under the effect of inoculated carbon source and temperature. OSPW treatment with an anaerobic sludge-inoculated MFC (AS-MFC) generated 0.55±0.025V, whereas an MFC inoculated with mature-fine tailings (MFT-MFC) generated 0.41±0.01V. An additional carbon source (acetate) significantly improved generated voltage. The voltage detected increased to 20-23% in MFCs when the condition was switched from ambient to mesophilic. The mesophilic condition increased OSPW treatment efficiency in terms of lowering the chemical oxygen demand and acid-extractable organics. Pyrosequencing analysis of microbial consortia revealed that Proteobacteria were the most abundant in MFCs and microbial communities in the AS-MFC were more diverse than those in the MFT-MFC. PMID:25103035

Choi, Jeongdong; Liu, Yang

2014-10-01

350

Spontaneous Emergence of Order in Vibrated Sand*  

NASA Astrophysics Data System (ADS)

Granular media such as sand, pharmaceuticals, cereal, cosmetics, and asteroids are involved in many processes, yet granular media remain less well understood than fluids and solids. Vertically oscillating granular layers provide a test bed for theory and modeling of granular dynamics. Experiments on vertically oscillating granular layers have revealed a variety of spatial patterns that emerge spontaneously as a function of the container acceleration amplitude and frequency: stripes, squares, hexagons, spirals, and oscillons (localized structures). Molecular dynamics simulations yield results in quantitative accord with laboratory observations. Since the gradients of density and velocity are large over a particle mean free path, the applicability of continuum theory has been questionable. However, hydrodynamic equations proposed for dissipative particles yield results in surprising qualitative accord with the laboratory observations. *Work in collaboration with C. Bizon, D. Goldman, W.D. McCormick, S.J. Moon, E. Rericha, M. Shattuck, and J. Swift. Supported by DOE.

Swinney, Harry L.

2004-05-01

351

Coagulation in the sand crab (Ovalipes bipustulatus).  

PubMed

The coagulation mechanism of the sand crab (O. bipustulatus) has been investigated. From the coagulocytes (amoebocytes) present in the crab haemolymph (blood), fibrinogen (coagulogen) was isolated. It was shown to be homogeneous by electrophoresis on S.D.S. polyacrylamide gel and had a molecular weight similar to the A alpha-chain of human fibrinogen. Unlike human fibrinogen. Unlike human fibrinogen it cannot be dissociated by reduction. In fibrin polymerization, a crosslinking process takes place and this process was inhibited by glycine ethyl ester. A fibrin stabilizing factor is present in the crab haemolymph and this protein was able to cross-link human fibrin in the same manner as human factor XIII. PMID:505375

Madaras, F; Parkin, J D; Castaldi, P A

1979-08-31

352

Acoustic sand detector for fluid flowstreams  

DOEpatents

The particle volume and particle mass production rate of particulate solids entrained in fluid flowstreams such as formation sand or fracture proppant entrained in oil and gas production flowstreams is determined by a system having a metal probe interposed in a flow conduit for transmitting acoustic emissions created by particles impacting the probe to a sensor and signal processing circuit which produces discrete signals related to the impact of each of the particles striking the probe. The volume or mass flow rate of particulates is determined from making an initial particle size distribution and particle energy distribution and comparing the initial energy distribution and/or the initial size distribution with values related to the impact energies of a predetermined number of recorded impacts. The comparison is also used to recalibrate the system to compensate for changes in flow velocity.

Beattie, Alan G. (Corrales, NM); Bohon, W. Mark (Frisco, TX)

1993-01-01

353

Great Sand Dunes National Monument and Preserve  

NSDL National Science Digital Library

This National Park Service website describes the natural resources of this park such as plants, mammals and birds (with species lists); endemic or rare species; geology; hydrology; and wind (eolian) systems. These natural resources include a high mountain valley holding the tallest dunes in North America and flanked by some of the highest peaks in the Rocky Mountains; unique wind-powered geologic systems; insects physically adapted to life in the sand and found nowhere else; alpine lakes and tundra; disappearing ponds; and interdunal wetlands. There is information on hiking and camping in the park and planning a visit; cultural history of the park area including that of ancient Americans; and a photo gallery.

354

Method and apparatus for hydrocarbon recovery from tar sands  

DOEpatents

A method and apparatus for utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000/degree/F in a burner to remove residual char and produce a solid waste that is easily disposable. The process and apparatus have the advantages of being able to utilize tar sands having a broad range of bitumen content and the advantage of producing product gases that are free from combustion gases and thereby have a higher heating value. Another important advantage is rapid pyrolysis of the tar sands in the cyclone so as to effectively utilize smaller sized reactor vessels for reducing capitol and operating costs. 1 fig., 1 tab.

Westhoff, J.D.; Harak, A.E.

1988-05-04

355

Drained cavity expansion in sands exhibiting particle crushing  

NASA Astrophysics Data System (ADS)

The expansion of cylindrical and spherical cavities in sands is modelled using similarity solutions. The conventional Mohr-Coulomb failure criterion and the state parameter sand behaviour model, which enables hardening-softening, are used in the analysis. The sand state is defined in terms of a new critical state line, designed to account for the three different modes of compressive deformation observed in sands across a wide range of stresses including particle rearrangement, particle crushing and pseudoelastic deformation. Solutions are generated for cavities expanded from zero and finite radii and are compared to those solutions where a conventional critical state line has been used. It is shown that for initial states typical of real quartz sand deposits, pseudoelastic deformation does not occur around an expanding cavity. Particle crushing does occur at these states and causes a reduction in the stress surrounding the cavity. This has major implications when using cavity expansion theory to interpret the cone penetration test and pressuremeter test.

Russell, A. R.; Khalili, N.

2002-04-01

356

40 CFR 436.30 - Applicability; description of the construction sand and gravel subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the construction sand and gravel subcategory. 436.30 Section...PROCESSING POINT SOURCE CATEGORY Construction Sand and Gravel Subcategory § 436.30 Applicability; description of the construction sand and gravel subcategory. The...

2010-07-01

357

76 FR 68503 - Ungulate Management Plan/Environmental Impact Statement, Great Sand Dunes National Park and...  

Federal Register 2010, 2011, 2012, 2013

...Environmental Impact Statement, Great Sand Dunes National Park and Preserve, CO AGENCY...for the Ungulate Management Plan, Great Sand Dunes National Park and Preserve...for the Ungulate Management Plan, Great Sand Dunes National Park and Preserve,...

2011-11-04

358

43 CFR 3141.2 - Prelease exploration within Special Tar Sand Areas.  

Code of Federal Regulations, 2011 CFR

...false Prelease exploration within Special Tar Sand Areas. 3141.2 Section 3141.2 Public...MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.2 Prelease exploration...

2011-10-01

359

40 CFR 436.40 - Applicability; description of the industrial sand subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the industrial sand subcategory. 436.40 Section 436...PROCESSING POINT SOURCE CATEGORY Industrial Sand Subcategory § 436.40 Applicability; description of the industrial sand subcategory. The provisions of...

2011-07-01

360

40 CFR 436.30 - Applicability; description of the construction sand and gravel subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the construction sand and gravel subcategory. 436.30 Section...PROCESSING POINT SOURCE CATEGORY Construction Sand and Gravel Subcategory § 436.30 Applicability; description of the construction sand and gravel subcategory. The...

2011-07-01

361

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

Code of Federal Regulations, 2011 CFR

...false Disposal plan for embedded gravel, sand or stone. 644.505 Section 644...Standing Timber, Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior to offering...

2011-07-01

362

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

Code of Federal Regulations, 2010 CFR

...true Disposal plan for embedded gravel, sand or stone. 644.505 Section 644...Standing Timber, Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior to offering...

2010-07-01

363

Climate change impacts on sand supply and the formation of desert sand dunes in the south-west  

E-print Network

) and Namib Desert (Vogel, 1989; Teller et al., 1990) of Africa to the deserts of the American southClimate change impacts on sand supply and the formation of desert sand dunes in the south-west U.S.A. Mich`ele L. Clarke* & Helen M. Rendell *Department of Geography, University College London, 26 Bedford

Clarke, Michèle

364

Fine Guidance Sensing for Coronagraphic Observatories  

NASA Technical Reports Server (NTRS)

Three options have been developed for Fine Guidance Sensing (FGS) for coronagraphic observatories using a Fine Guidance Camera within a coronagraphic instrument. Coronagraphic observatories require very fine precision pointing in order to image faint objects at very small distances from a target star. The Fine Guidance Camera measures the direction to the target star. The first option, referred to as Spot, was to collect all of the light reflected from a coronagraph occulter onto a focal plane, producing an Airy-type point spread function (PSF). This would allow almost all of the starlight from the central star to be used for centroiding. The second approach, referred to as Punctured Disk, collects the light that bypasses a central obscuration, producing a PSF with a punctured central disk. The final approach, referred to as Lyot, collects light after passing through the occulter at the Lyot stop. The study includes generation of representative images for each option by the science team, followed by an engineering evaluation of a centroiding or a photometric algorithm for each option. After the alignment of the coronagraph to the fine guidance system, a "nulling" point on the FGS focal point is determined by calibration. This alignment is implemented by a fine alignment mechanism that is part of the fine guidance camera selection mirror. If the star images meet the modeling assumptions, and the star "centroid" can be driven to that nulling point, the contrast for the coronagraph will be maximized.

Brugarolas, Paul; Alexander, James W.; Trauger, John T.; Moody, Dwight C.

2011-01-01

365

Mechanism of sand slide - cold lahar induced by extreme rainfall  

NASA Astrophysics Data System (ADS)

Along with the increasing frequencies of extreme rainfall events in almost every where on the earth, shallow slide - debris flow, i.e. cold lahars running long distance often occurs and claims downslope residents lives. In the midnight of 15 October 2013, Typhoon Wilpha attacked the Izu-Oshima, a active volcanic Island and the extreme rainfall of more than 800 mm / 24 hours was recorded. This downpour of more than 80 mm/hr lasted 4 hours at its peak and caused a number of cold lahars. The initial stage of those lahars was shallow slides of surface black volcanic ash deposits, containing mostly fine sands. The thickness was only 50 cm - 1 m. In the reconnaissance investigation, author found that the sliding surface was the boundary of two separate volcanic ash layers between the black and yellow colored and apparently showing contrast of permeability and hardness. Permeability contrast may have contributed to generation of excess pore pressure on the border and trigger the slide. Then, the unconsolidated, unpacked mass was easily fluidized and transformed into mud flows, that which volcanologists call cold lahars. Seismometers installed for monitoring the active volcano's activities, succeeded to detect many tremors events. Many are spikes but 5 larger and longer events were extracted. They lasted 2 -3 minutes and if we assume that this tremors reflects the runout movement, then we can calculate the mean velocity of the lahars. Estimated velocity was 45 - 60 km/h, which is much higher than the average speed 30 - 40 km/h of debris flows observed in Japan. Flume tests of volcanic ash flows by the Forestry and Forest Products Research Institute showed the wet volcanic ash can run at higher speed than other materials. The two tremor records were compare d with the local residents witnessed and confirmed by newspaper reported that the reach of the lahar was observed at the exact time when tremor ends. We took the black volcanic ash and conducted ring shear tests to reveal the mechanism of rapid motion. In the undrained or partially drained tests under pore water pressure test, monotonic loading of shear stress, and constant shear speed conditions, we found that immediately after failure takes place, a big excess pore pressure was generated and accelerating motions had stated in all cases. The reduced shear resistance thereafter was maintained because of the lasting high pore pressure. Even in the partially-drained test, we found once the pore pressure reached almost same with the normal stress and then gradually decreased due to dissipation. Those tests apparently shows that the high mobility and high acceleration of the motion are expected and this could be the key mechanism of the fluidization of initial shallow slides into sand flows, i.e., cold lahars. In the past ring shear test series on volcanic materials from fluidized landslides at El Picaccho of El Salvador, Mt Aso of Kumamto Prefecture, and Nagari Tandikat near Padang, Indonesia, show very similar trends. In all those cases, we expected serious grain crushing during shear, contributed to the generation of excess pore pressure, because those material are deposited recently (in geological time) and suffered no big overburden pressure which means no consolidation and no serious grain crushing ever before. So those volcanic materials are generally susceptible to crushing and expect high mobility when slides are initiated under fully saturated condition.

Fukuoka, Hiroshi; Yamada, Masumi; Dok, Atitkagna

2014-05-01

366

The effect of temperature on a variable permeability, two-stage sand consolidation technique  

E-print Network

-STAGE, SAND CONSOLIDATION TREATMENTS Page 15 17 17 17 21 27 INTRODUCTION Sand production from unconsolidated formations in oil and gas wells has been a major problem in the petroleum industry for many years. Sand production may result in reduced...-STAGE, SAND CONSOLIDATION TREATMENTS Page 15 17 17 17 21 27 INTRODUCTION Sand production from unconsolidated formations in oil and gas wells has been a major problem in the petroleum industry for many years. Sand production may result in reduced...

Barger, Blane Rene

2012-06-07

367

Have the northwest Negev dunefield sands reddened since their deposition?  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

368

Human fine body hair enhances ectoparasite detection  

PubMed Central

Although we are relatively naked in comparison with other primates, the human body is covered in a layer of fine hair (vellus and terminal hair) at a relatively high follicular density. There are relatively few explanations for the evolutionary maintenance of this type of human hair. Here, we experimentally test the hypothesis that human fine body hair plays a defensive function against ectoparasites (bed bugs). Our results show that fine body hair enhances the detection of ectoparasites through the combined effects of (i) increasing the parasite's search time and (ii) enhancing its detection. PMID:22171023

Dean, Isabelle; Siva-Jothy, Michael T.

2012-01-01

369

Tectonics and sedimentology along the Monkey River and Big Creek, southern Belize, Central America: Modern analog of select Morrow sands  

SciTech Connect

Big Creek is presently a relatively short river draining the flat coastal plain at the southern edge of the North American plate, south-central Belize. The recent sediments in this river consists of very fine-grained silts and clays derived from the local coastal plain. Offshore from the mouth of the Big Creek are shallow sand bars, channels, and eroding islands consisting of well-sorted, coarse sand comprised dominantly of feldspathic minerals. The location and geometry of these sands suggest that Big Creek was the fluvial source for this material. The sedimentology implication is that the nearshore and offshore parts of Big Creek represent a relatively large drowned deltaic complex, a modern analog of some lower Morrow depositional systems. Coarse feldspathic material found in the Cockscomb basin in the Maya Mountains is transported by the Swasey branch of the Monkey River toward the Big Creek drainage to the coast. However, the Swasey branch is abruptly diverted southward to intersect the present-day Monkey River. Drainage analysis suggests that structural features subsidiary to the Chixoy-Polochic fault zone bounding the North American plate may have diverted flow southward, beheading Big Creek. Field observations have not found any major relief changes which would have drainage analysis support tectonic diversion of the head waters of Big Creek into present-day Monkey River. Similar processes are hypothesized to have occurred during Morrow deposition.

Gries, J.C.; Full, W.E. (Wichita State Univ., KS (United States))

1991-08-01

370

Luminescence chronology of the inland sand dunes from SE India  

NASA Astrophysics Data System (ADS)

Records of past climate changes have been preserved variously on the earth's surface. Sand dunes are one such prominent imprint, and it is suggested that their presence is an indicator of periods of transition from arid to less arid phases. We report inland sand dunes from Andhra Pradesh (SE India) spread over an area of ~ 500 km2, ~ 75 km inland from the east coast. The dune sands are examined to understand their provenance, transportation, timing of sand aggradation and their relationship to past climates. The dune distribution, grain morphology and the grain-size studies on sands suggest an aeolian origin. Physiography of the study area, heavy mineral assemblage, and abundance of quartz in the parent rocks indicate that the dune sands are largely derived from first-order streams emanating from hills in the region and from weathering of the Nellore schist belt. It appears that the geomorphology and wind direction pattern both facilitated and restricted the dune aggradation and preservation to a limited area. OSL dating of 47 dune samples ranged from the present to ~ 50 ka, thereby suggesting a long duration of sand-dune aggradation and/or reworking history.

Reddy, Dontireddy Venkat; Singaraju, Vuddaraju; Mishra, Rakesh; Kumar, Devender; Thomas, Puthusserry Joseph; Rao, Karra Kameshwa; Singhvi, Ashok Kumar

2013-09-01

371

Wind Induced Raindrop Splash Sand Transport  

NASA Astrophysics Data System (ADS)

AGU abstract Title: Wind Induced Raindrop Splash Sand Transport Raindrop splash is widely accepted as an important mechanism of soil erosion (e.g. Van Dijk, Bruijnzeel, and Eisma 2003) as it can cause both particle detachment and transport. Since 1950, a number of papers have been published to identify and quantify the factors that influence splash transport (e.g. Ekern 1944; Rose 1960; Hudson 1963; Morgan 1981). More recently there has been attention focused on the combined processes of splash detachment and grain transport enhanced by the presence of wind using numerical models to simulate raindrop trajectories and terminal velocities as well as some empirical experiments to estimate the distribution of ejected particles. s (e.g. Erpul et al., 2009, 2008; Foulds and Warbuton 2007a, b; Cornelis et al. 2004a, 2004b; Erpul, Norton, and Gabriels 2002). These efforts have ignored the role of wind in altering particle trajectories after the initiation drop-induced ejection. The purpose of this paper is to use numerical simulation to describe the wind-enhanced splash transport process for a flat, sandy surface before and after a splash event. In this study, we first consider a single falling raindrop and use a physics model to analyze its behavior in the air, at impact and then the behaviors of droplets and grains ejected by the splash. The simulation shows that the speed of the raindrop relative to the wind speed is zero, but the relative speed increases rapidly very near the surface. The angle of drop incidence and terminal velocity are functions of drop size and the wind velocity profile. Once the raindrop hits the surface, a number of droplets are ejected; most of them include a number of sand particles. We apply several empirical measurements to represent the distributions of ejected drop sizes, number of grains entrained, and the angles and speeds of ejecta, and then use a coordinate transformation to convert them into conditions related to the angle of incidence of the impinging raindrop. The transport distance is the function of near-surface wind speed, droplet size, and ejection angle and speed. As the ejecting droplets are very small, resaltation after their impact is not considered. After we get the result from a single raindrop, we enlarge our picture to all the raindrops in a certain rainfall event, and then estimate the transport rate to all the directions from the estimate of raindrop distribution. The simulated results are compared with some empirical studies for verification purposes. In summary, the process of wind induced raindrop splash sand transport is very complex. Wind plays a role in the changing the raindrop terminal velocity and incidence angle and the droplets flying distance and direction. Numerical simulation can help us to understand on the internal mechanism of the whole wind induced splash process.

Li, B.; Sherman, D.

2009-12-01

372

Fine needle aspiration of the thyroid  

MedlinePLUS

Thyroid nodule fine needle aspirate biopsy; Biopsy - thyroid - skinny-needle; Skinny-needle thyroid biopsy ... under your shoulders and your neck extended. The biopsy site is cleaned. A thin needle is inserted ...

373

DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS  

EPA Science Inventory

Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

374

DESIGN MANUAL: FINE PORE AERATION SYSTEMS  

EPA Science Inventory

This manual presents the best current practices for selecting, designing, operating, maintaining, and controlling fine pore aeration systems used in the treatment of municipal wastewater. It was prepared by the American Society of Civil Engineers Committee on Oxygen Transfer unde...

375

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC INTEGRATED COMPOSITION, IMPROVISATION, AND TECHNOLOGY (ICIT) Degree Requirements (2014-2015) Music 209 (Creative Practices): Must be taken every quarter of the first year in residence. 12 units ______ ______ ______ Music 212

Loudon, Catherine

376

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC VOCAL ARTS Degree Requirements (2013-2014) Music 164 (Opera Workshop) ______ ______ 4 units Music 200 (Bibliography) ______ 4 units Music 201A-B (Analysis) ______ ______ 8 units Music 220, 230, 235, or 236 (Graduate Seminar

Barrett, Jeffrey A.

377

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC GUITAR/LUTE PERFORMANCE Degree Requirements (2013-2014) Music 176 (Chamber Ensembles) ______ ______ ______ 6 units Music 189 (Accompanying for Plucked Strings) ______ ______ ______ 6 units Music 200 (Bibliography) ______ 4 units Music 201A

Barrett, Jeffrey A.

378

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC PIANO PERFORMANCE Degree Requirements (2014-2015) Music 131 (Post-Tonal Theory) ______ 4 units Music 176 (Chamber Ensembles) ______ ______ ______ 6 units Music 200 (Bibliography) ______ 4 units Music 201 (Analysis) ______ 4 units Music 211

Loudon, Catherine

379

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC INSTRUMENTAL PERFORMANCE Degree Requirements (2012-2013) Music 176 (Chamber Ensembles) ______ ______ ______ 3 units Music 200 (Bibliography) ______ 4 units Music 201A-B (Analysis) ______ ______ 8 units Music 220, 230, 235 (Graduate Seminar

Stanford, Kyle

380

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC INTEGRATED COMPOSITION, IMPROVISATION, AND TECHNOLOGY (ICIT) Degree Requirements (2011-2012) · Music 209 (Creative Practices): Must be taken every quarter of the first year in residence. 12 units ______ ______ ______ · Music 212

Rose, Michael R.

381

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC GUITAR/LUTE PERFORMANCE Degree Requirements (2012-2013) Music 176 (Chamber Ensembles) ______ ______ ______ 3 units Music 189 (Accompanying for Plucked Strings) ______ ______ ______ 6 units Music 200 (Bibliography) ______ 4 units Music 201A

Stanford, Kyle

382

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC VOCAL ARTS Degree Requirements (2012-2013) Music 164 (Opera Workshop) ______ ______ ______ 6 units Music 200 (Bibliography) ______ 4 units Music 201A-B (Analysis) ______ ______ 8 units Music 220, 230, 235 (Graduate Seminar

Stanford, Kyle

383

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC GUITAR/LUTE PERFORMANCE Degree Requirements (2014-2015) Music 131 (Post-Tonal Theory) ______ 4 units Music 176 (Chamber Ensembles) ______ ______ ______ 6 units Music 189 (Accompanying for Plucked Strings) ______ ______ ______ 6 units Music 200

Loudon, Catherine

384

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC COLLABORATIVE PIANO Degree Requirements (2012-2013) Music 156A-B-C (Song Literature) ______ ______ ______ 6 units Music 158A requirement. Music 176 (Chamber Ensembles) ______ ______ ______ 3 units Music 200 (Bibliography) ______ 4

Stanford, Kyle

385

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC INTEGRATED COMPOSITION, IMPROVISATION, AND TECHNOLOGY (ICIT) Degree Requirements (2012-2013) Music 209 (Creative Practices): Must be taken every quarter of the first year in residence. 12 units ______ ______ ______ Music 212

Stanford, Kyle

386

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC INSTRUMENTAL PERFORMANCE Degree Requirements (2014-2015) Music 131 (Post-Tonal Theory) ______ 4 units Music 160, or 161 (Large Ensemble of 12 units of Music 160, 161. ______ ______ ______ ______ ______ ______ Music 176 (Chamber Ensembles

Loudon, Catherine

387

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC INTEGRATED COMPOSITION, IMPROVISATION, AND TECHNOLOGY (ICIT) Degree Requirements (2013-2014) Music 209 (Creative Practices): Must be taken every quarter of the first year in residence. 12 units ______ ______ ______ Music 212

Loudon, Catherine

388

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC MUSICOLOGY Degree Requirements (2014-2015) Music 200 (Bibliography and Resesarch) ______ 4 units Music 201 (Topics in Analysis) ______ 4 units Music 203 (Music Thesis): ______ 4 units Music 235 (Critical Studies in Music) ______ 4

Loudon, Catherine

389

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC PIANO PERFORMANCE Degree Requirements (2012-2013) Music 176 (Chamber Ensembles) ______ ______ ______ 3 units Music 200 (Bibliography) ______ 4 units Music 201A-B (Analysis) ______ ______ 8 units Music 220, 230, 235 (Graduate Seminar

Stanford, Kyle

390

Name: _______________________________ MASTER OF FINE ARTS: MUSIC  

E-print Network

Name: _______________________________ MASTER OF FINE ARTS: MUSIC VOCAL ARTS Degree Requirements (2014-2015) Music 131 (Post-Tonal Theory) ______ 4 units Music 164 (Opera Workshop) ______ ______ 4 units Music 200 (Bibliography) ______ 4 units Music 201 (Analysis) ______ 4 units Music 211 (Vocal

Loudon, Catherine

391

TECHNOLOGY ASSESSMENT OF FINE BUBBLE AERATORS  

EPA Science Inventory

This technology assessment addresses design and evaluation of fine bubble aeration equipment. It discusses the associated gas transfer theory used as the basis for measuring water and wastewater oxygenation efficiency. Mixing requirements are also discussed. While bubble aeration...

392

Method of increasing fine coal filtration efficiency  

SciTech Connect

Fine coals suspended in a coal flotation froth are more efficiently filtered when the flotation froth is subjected to a thickening operation prior to filtration. The thickening operation is accomplished by the use of a clarifier or thickener.

Moyer, W.H.

1981-01-13

393

Depositional settings of sand beaches along whitewater rivers  

USGS Publications Warehouse

The numbers and sizes of sand beaches suitable for recreation along selected whitewater rivers in the western United States depend on sand concentrations, range of discharge and the size, frequency and type of depositional settings. River-width expansions downstream from constrictions are the predominant depositional setting for sand beaches in the upper Grand Canyon and along five Wild and Scenic Rivers in Idaho, but not along other rivers. Beaches located upstream from constrictions are rare, in general, except in the Grand Canyon. Beaches found in expansions without constrictions dominate depositional sites along the Yampa and Green Rivers, are fairly common along the rivers in Idaho, but are relatively rare in the Grand Canyon. The magnitude of flow expansion is a reliable predictor of beach size. Beaches located on the inside of curves are uncommon, in general, but can be important recreation sites. The mid-channel bar setting is the least important from a recreation standpoint because that setting is rare and beaches there are typically small, and emergent only at low flow. The frequency of beaches is highly variable among rivers and the concentration of sand in transport is only partially responsible. Of the rivers studied, the unregulated Yampa River carries the highest concentrations of suspended sand and has among the most beaches (1.2 beaches km-1). Emergent sand beaches are essentially nonexistent along the Deschutes River and are rare along other Oregon rivers, yet these rivers transport some sand. Sand beaches are fairly common (0.8-1.1 beaches km-1) along the regulated Colorado River, but are comparatively rare (0.6 beaches km-1) along the unregulated Middle Fork Salmon River. The suspended sand concentrations in study reaches of these two rivers are similar, and the difference in the frequency of beaches may be largely because the processes that create beach-deposition settings are less active along the Middle Fork Salmon.

Vincent, K.R.; Andrews, E.D.

2008-01-01

394

DCS of Syrtis Major Sand Migration  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released August 2, 2004 This image shows two representations of the same infra-red image of craters and lava flow features in Syrtis Major. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

The prominent rim of the large crater at the top of the image is blocking migrating sand from entering the crater. This produces a very distinct compositional boundary between the pink/magenta basaltic sand and the green dust covering the crater rim and floor. Many of the smaller craters in this region have dust trails behind them, indicating the prevailing wind direction. At the top of the image, the prevailing wind direction is to the northwest, while at the bottom of the image, the prevailing winds have shifted towards the southwest.

Image information: IR instrument. Latitude 9.2, Longitude 68.4 East (291.6 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2004-01-01

395

Arthropod monitoring for fine-scale habitat analysis: A case study of the El Segundo sand dunes  

SciTech Connect

Arthropod communities from several habitats on and adjacent to the El Segundo dunes (Los Angeles County, CA) were sampled using pitfall and yellow pan traps to evaluate their possible use as indicators of restoration success. Communities were ordinated and clustered using correspondence analysis, detrended correspondence analysis, two-way indicator species analysis, and Ward's method of agglomerative clustering. The results showed high repeatability among replicates within any sampling arena that permits discrimination of (1) degraded and relatively undisturbed habitat, (2) different dune habitat types, and (3) annual change. Canonical correspondence analysis showed a significant effect of disturbance history on community composition that explained 5--20% of the variation. Replicates of pitfall and yellow pan traps on single sites clustered together reliably when species abundance was considered, whereas clusters using only species incidence did not group replicates as consistently. The broad taxonomic approach seems appropriate for habitat evaluation and monitoring of restoration projects as an alternative to assessments geared to single species or even single families.

Mattoni, R.; Longcore, T.; Novotny, V.

2000-04-01

396

Fluidized-Bed Particles Scavenge Silicon Fines  

NASA Technical Reports Server (NTRS)

Waste reduced, and silicon production rate improved. In new process silicon formed by thermal decomposition of SiH4. Part of silicon formed on silicon seed particles as result of surface chemical reaction. However, silicon formed by homogeneous reaction in gas phase tends to form aggregates of silicon atoms, which appear as fine particles (like dust). Believed that scavenging action of seed particles enables large fraction fines to be incorporated onto seed surface. This mode of growth confirmed by electron microscopy photographs.

Hsu, G. C.; Rohatgi, N.; Lutwack, R.; Hogle, R.

1985-01-01

397

Electronic Properties of Metallic Fine Particles. I  

Microsoft Academic Search

The level spacing of quantized electronic states becomes fairly large in very fine particles. For instance, it will be comparable to kT at T{=}1°K if the linear dimension of a particle is 50 Å or so. Thermal properties may show considerable deviations from the normal bulk values for such fine particles. The heat capacity will be reduced to about two-thirds

Ryogo Kubo

1962-01-01

398

Sand-Fly Saliva-Leishmania-Man: The Trigger Trio  

PubMed Central

Leishmaniases are worldwide diseases transmitted to the vertebrate host by the bite of an infected sand-fly. Sand-fly biting and parasite inoculation are accompanied by the injection of salivary molecules, whose immunomodulatory properties are actively being studied. This mini review focuses on how the interactions between sand-fly saliva and the immune system may shape the outcome of infection, given its immunomodulatory properties, in experimental models and in the endemic area. Additionally, we approach the recent contributions regarding the identification of individual salivary components and how these are currently being considered as additional components of a vaccine against leishmaniasis. PMID:24312093

Oliveira, Fabiano; de Carvalho, Augusto M.; de Oliveira, Camila I.

2013-01-01

399

BLAISDELL SLOW SAND FILTER WASHING MACHINE. VIEW LOOKING SOUTHEAST. THE ...  

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

BLAISDELL SLOW SAND FILTER WASHING MACHINE. VIEW LOOKING SOUTHEAST. THE ELECTRIC TROLLEY IS SEEN AT THE LEFT. THE BULKHEAD SEEN AT THE LOWER RIGHT IS NOT PART OF THE MACHINE; IT WAS INSTALLED TO RETAIN THE FILTER SAND AFTER THE MACHINE WAS NO LONGER USED. THE NORTHWEST CORNER OF SETTLING RESERVOIR NO. 4 IS SEEN IN THE DISTANCE BELOW THE RIGHT SIDE OF THE TROLLEY. - Yuma Main Street Water Treatment Plant, Blaisdell Slow Sand Filter Washing Machine, Jones Street at foot of Main Street, Yuma, Yuma County, AZ

400

Pelletization of fine coals. Final report  

SciTech Connect

Coal is one of the most abundant energy resources in the US with nearly 800 million tons of it being mined annually. Process and environmental demands for low-ash, low-sulfur coals and economic constraints for high productivity are leading the coal industry to use such modern mining methods as longwall mining and such newer coal processing techniques as froth flotation, oil agglomeration, chemical cleaning and synthetic fuel production. All these processes are faced with one common problem area--fine coals. Dealing effectively with these fine coals during handling, storage, transportation, and/or processing continues to be a challenge facing the industry. Agglomeration by the unit operation of pelletization consists of tumbling moist fines in drums or discs. Past experimental work and limited commercial practice have shown that pelletization can alleviate the problems associated with fine coals. However, it was recognized that there exists a serious need for delineating the fundamental principles of fine coal pelletization. Accordingly, a research program has been carried involving four specific topics: (i) experimental investigation of coal pelletization kinetics, (ii) understanding the surface principles of coal pelletization, (iii) modeling of coal pelletization processes, and (iv) simulation of fine coal pelletization circuits. This report summarizes the major findings and provides relevant details of the research effort.

Sastry, K.V.S.

1995-12-31

401

Preliminary assessments of the occurrence and effects of utilization of sand and aggregate resources of the Louisiana inner shelf  

USGS Publications Warehouse

Louisiana is experiencing the most critical coastal erosion and land loss problem in the United States. Shoreline erosion rates exceed 6 m/yr in more than 80% of the Louisiana coastal zone and can be up to 50 m/yr in areas impacted by hurricanes. The barrier islands have decreased in area by some 40% since 1880. Land loss from coastal marshlands and ridgelands from both natural and human-induced processes is estimated to exceed 100 km2/yr. In response, a two-phase plan has been established, calling for barrier-island restoration and beach nourishment, both requiring large amounts of sand. The plan will be cost-effective only if sand can be found offshore in sufficient quantities close to project sites. To locate such deposits, the Louisiana Geological Survey is conducting an inventory of nearshore sand resources on the Louisiana continental shelf. Exploration for offshore sand deposits is conducted in two phases, with high-resolution seismic reflection profiling to locate potential sand bodies followed by vibracoring to confirm seismic intepretations and obtain samples for textural characterization. As part of the initial stages of the program, reconnaissance high-resolution seismic investigations of three areas of the continental shelf representing different stages in the evolutionary sequence of barrier shorelines were carried out. The Timbalier Islands, flanking barriers of the eroding Caminada-Moreau headland, contain potential sand resources associated with buried tidal and distributary channels. The Chandeleur Islands, a barrier-island arc, have potential offshore sands in the form of truncated spit and tidal inlet deposits, submerged beach ridges, and distributary channels. Trinity Shoal, an inner shelf shoal, is an offshore feature containing up to 2 ?? 109 m3 of material, most of which is probably fine sand. These reconnaissance surveys have demonstrated the occurrence of sand resources on the Louisiana continental shelf. Utilization of such deposits for island restoration or beach nourishment raises the question of potential adverse effects on the shoreline due to alteration of the inner shelf bathymetry by removing material or deposition of spoil in the process of dredging. Wave refraction analysis models provide a means by which hypothetical wave energy distribution can be determined and possible changes due to resource utilization assessed. A preliminary assessment of the consequences of using sand from Ship Shoal, a large shore-parallel feature, as borrow material for beach nourishment was conducted. Initial results indicate that the shoal serves to attenuate storm waves, and removal of this feature would result in increased erosion and overwash on the adjacent Isles Dernieres barrier-island shoreline. These findings illustrate the need to determine optimum dredging configurations if environmentally deleterious effects of utilization of offshore and aggregate resources are to be minimized. ?? 1989.

Suter, J. R.; Mossa, J.; Penland, S.

1989-01-01

402

Aerolian erosion, transport, and deposition of volcaniclastic sands among the shifting sand dunes, Christmas Lake Valley, Oregon: TIMS image analysis  

NASA Technical Reports Server (NTRS)

Remote sensing is a tool that, in the context of aeolian studies, offers a synoptic view of a dune field, sand sea, or entire desert region. Blount et al. (1990) presented one of the first studies demonstrating the power of multispectral images for interpreting the dynamic history of an aeolian sand sea. Blount's work on the Gran Desierto of Mexico used a Landsat TM scene and a linear spectral mixing model to show where different sand populations occur and along what paths these sands may have traveled before becoming incorporated into dunes. Interpretation of sand transport paths and sources in the Gran Desierto led to an improved understanding of the origin and Holocene history of the dunes. With the anticipated advent of the EOS-A platform and ASTER thermal infrared capability in 1998, it will become possible to look at continental sand seas and map sand transport paths using 8-12 mu m bands that are well-suited to tracking silicate sediments. A logical extension of Blount's work is to attempt a similar study using thermal infrared images. One such study has already begun by looking at feldspar, quartz, magnetite, and clay distributions in the Kelso Dunes of southern California. This paper describes the geology and application of TIMS image analysis of a less-well known Holocene dune field in south central Oregon using TIMS data obtained in 1991.

Edgett, Kenneth S.; Ramsey, Michael S.; Christensen, Philip R.

1995-01-01

403

Denitrification in a Sand and Gravel Aquifer  

PubMed Central

Denitrification was assayed by the acetylene blockage technique in slurried core material obtained from a freshwater sand and gravel aquifer. The aquifer, which has been contaminated with treated sewage for more than 50 years, had a contaminant plume greater than 3.5-km long. Near the contaminant source, groundwater nitrate concentrations were greater than 1 mM, whereas 0.25 km downgradient the central portion of the contaminant plume was anoxic and contained no detectable nitrate. Samples were obtained along the longitudinal axis of the plume (0 to 0.25 km) at several depths from four sites. Denitrification was evident at in situ nitrate concentrations at all sites tested; rates ranged from 2.3 to 260 pmol of N2O produced (g of wet sediment)?1 h?1. Rates were highest nearest the contaminant source and decreased with increasing distance downgradient. Denitrification was the predominant nitrate-reducing activity; no evidence was found for nitrate reduction to ammonium at any site. Denitrifying activity was carbon limited and not nitrate limited, except when the ambient nitrate level was less than the detection limit, in which case, even when amended with high concentrations of glucose and nitrate, the capacity to denitrify on a short-term basis was lacking. These results demonstrate that denitrification can occur in groundwater systems and, thereby, serve as a mechanism for nitrate removal from groundwater. PMID:16347621

Smith, Richard L.; Duff, John H.

1988-01-01

404

Models of compacted fine-grained soils used as mineral liner for solid waste  

NASA Astrophysics Data System (ADS)

To prevent the leakage of pollutant liquids into groundwater and sublayers, the compacted fine-grained soils are commonly utilized as mineral liners or a sealing system constructed under municipal solid waste and other containment hazardous materials. This study presents the correlation equations of the compaction parameters required for construction of a mineral liner system. The determination of the characteristic compaction parameters, maximum dry unit weight ( ? dmax) and optimum water content ( w opt) requires considerable time and great effort. In this study, empirical models are described and examined to find which of the index properties correlate well with the compaction characteristics for estimating ? dmax and w opt of fine-grained soils at the standard compactive effort. The compaction data are correlated with different combinations of gravel content ( G), sand content ( S), fine-grained content (FC = clay + silt), plasticity index ( I p), liquid limit ( w L) and plastic limit ( w P) by performing multilinear regression (MLR) analyses. The obtained correlations with statistical parameters are presented and compared with the previous studies. It is found that the maximum dry unit weight and optimum water content have a considerably good correlation with plastic limit in comparison with liquid limit and plasticity index.

Sivrikaya, Osman

2008-02-01

405

Documenting the global impacts of beach sand mining  

NASA Astrophysics Data System (ADS)

For centuries, beach sand has been mined for use as aggregate in concrete, for heavy minerals, and for construction fill. The global extent and impact of this phenomenon has gone relatively unnoticed by academics, NGOs, and major news sources. Most reports of sand mining activities are found at the very local scale (if the mining is ever documented at all). Yet, sand mining in many localities has resulted in the complete destruction of beach (and related) ecosystems along with severe impacts to coastal protection and tourism. The Program for the Study of Developed Shorelines at Western Carolina University and Beachcare.org have initiated the construction of a global database of beach sand mining activities. The database is being built through a combination of site visits and through the data mining of media resources, peer reviewed papers, and reports from private and governmental entities. Currently, we have documented sand mining in 35 countries on 6 continents representing the removal of millions of cubic meters of sand. Problems extend from Asia where critical infrastructure has been disrupted by sand mining to the Caribbean where policy reform has swiftly followed a highly publicized theft of sand. The Program for the Study of Developed Shorelines recently observed extensive sand mining in Morocco at the regional scale. Tens of kilometers of beach have been stripped of sand and the mining continues southward reducing hope of a thriving tourism-based economy. Problems caused by beach sand mining include: destruction of natural beaches and the ecosystems they protect (e.g. dunes, wetlands), habitat loss for globally important species (e.g. turtles, shorebirds), destruction of nearshore marine ecosystems, increased shoreline erosion rates, reduced protection from storms, tsunamis, and wave events, and economic losses through tourist abandonment and loss of coastal aesthetics. The threats posed by sand mining are made even more critical given the prospect of a significant rise in global sea level over the coming decades. Most governments recognize the local impacts of sand mining and mining activities are illegal in many localities. However, enforcement of these protections has been problematic and there has been little pressure to stop the practice from local or international environmental groups. In many cases, addressing the issue of sand mining requires addressing the local issues that allow it to persist. This includes poverty, corruption, and unregulated development. In areas where beach sand mining significantly supports the local economy, care needs to be given that local workers are given alternative means of income, and builders are provided an affordable substitute for the sand (e.g. crushed rock). Regardless, it is time for both academics and NGOs to address the cumulative environmental impacts of the direct destruction of the world's beaches through mining activities.

Young, R.; Griffith, A.

2009-04-01

406

38. SAND HANDLING UNIT #1, SHOWING TIMBER FRAMING OF ORIGINAL ...  

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

38. SAND HANDLING UNIT #1, SHOWING TIMBER FRAMING OF ORIGINAL GREY IRON FOUNDRY SAWTOOTH ROOF. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

407

18. SAND BEACH WITH SUNBATHERS AND UMBRELLAS. VIEW FROM SOUTHEAST. ...  

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

18. SAND BEACH WITH SUNBATHERS AND UMBRELLAS. VIEW FROM SOUTHEAST. NORTHWEST ELEVATION OF REFRESHMENT STAND Photocopy of 1930-1940 photograph - Glen Echo Park, Crystal Swimming Pool, 7300 McArthur Boulevard, Glen Echo, Montgomery County, MD

408

Experimental results on the freezing of saturated sands  

NASA Astrophysics Data System (ADS)

Experimental freezings of two liquids (water and tert-amyl-alcohol) in sands were carried on in a closed system. A sand with known grain size distribution, mineralogic composition and physical properties has been used. An experimental apparatus reproducing a one dimensional heat transfer phenomenon was set up. The low plane was thermally insulated and the upper one was kept at constant temperature. A procedure of vibration of the sand was employed to have a uniform liquid regain distribution at the beginning of the cooling. Temperature was measured at different distances from the cold source during the cooling. Liquid regain distributions were measured at the end of the freezing process with the oven drying method. Conductive heat transfer with change of phase was theoretically investigated. The energy equation was solved numerically with the finite difference method of Crank. The thermal conductivity of the wet sand was determined.

Gori, F.; Ughi, M.

409

[Influence of perlite sand on the skin in experiment].  

PubMed

In the present work influence of perlite sand has been studied on a skin of Sprague-Dawley male rat (300-350 g). The biopsy of intact rat skin has been used as control. Contact of the perlite sand with animals' skin causes the reaction of an inflammation amplifying with increase of duration of the influence of substance. Therefore, despite an inert chemical compound, long contact with perlite sand in conditions of production can promote development of skin diseases. From the result of this investigation it is concluded that perlite sand causes irritating action on the skin and it is necessary to apply additional protective means to workers contacting to this substance. PMID:22702133

Dracheva, E E; Iatsyna, I V; Lapina, N E; Ianin, V A; Antoshina, L I; Zhadan, I Iu; Krasavina, E K

2012-01-01

410

Bathymetric evolution of sand bed forms under partially standing waves  

E-print Network

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

Landry, Blake Jude

2004-01-01

411

Dust and Sand Forecasting in Iraq and Adjoining Countries.  

National Technical Information Service (NTIS)

This report, based partly on the author's recent personal experience in desert weather forecasting, discusses airborne dust and sand in Iraq, Kuwait, Syria, eastern Jordan, western Iran, and the northern Arabian Peninsula. It describes geography of the re...

W. D. Wilderson

1991-01-01

412

Yellowstone Sand Verbena (Abronia ammophila): A Yellowstone Lake Endemic  

E-print Network

Yellowstone sand verbena, Abronia ammophila Greene, is restricted to stabilized sand sites that principally lie just above the maximum splash zone along the shoreline of Yellowstone Lake. A 1998 survey of the entire population found little more than 8,000 plants, most of which were seedlings. A summation of current knowledge regarding the life history of the species is presented, though many aspects still require further elucidation. Historical collections suggest that this species was more widely distributed around the lake in the early years after the park’s establishment. The high level of human activity on the beaches, especially along the northern shoreline of the lake, may have resulted in the extirpation of the sand verbena from significant portions of its original range. The longterm survival of Yellowstone sand verbena is in doubt if the remaining sites are adversely affected. Strategies will be presented to help insure the continued survival of this unique endemic.

unknown authors

413

Depleted-uranium recovery from and cleaning of target sands  

SciTech Connect

This patent describes a method of removing uranium and its oxidation products from target sands and consists of: (a) providing a container means which can be heated; (b) adding uranium-containing target sands to the container; (c) adding a salt mixture comprising at least 70 weight percent of a salt selected from the group consisting of nitrates of magnesium, calcium, potassium, sodium, and lithium to the container; (d) heating the target sands and the salt mixture together to fuse the salt to convert the uranium to uranium oxidation products; (e) adding water to dissolve the salt component into aqueous solution and removing the aqueous solution; (f) adding nitric acid to dissolve the uranium oxidation products into aqueous nitric acid solution; and (g) rinsing the target sands with water washing out the dissolved uranium oxidation products.

Elliott, G.R.B.

1986-02-04

414

Fine Shades of a Sombrero  

NASA Astrophysics Data System (ADS)

In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104 , widely known as the "Sombrero" (the Mexican hat) because of its particular shape. The colour image was made by a combination of three CCD images from the FORS1 multi-mode instrument on VLT ANTU , recently obtained by Peter Barthel from the Kapteyn Institute (Groningen, The Netherlands) during an observing run at the Paranal Observatory. He and Mark Neeser , also from the Kapteyn Institute, produced the composite images. The galaxy fits perfectly into the 6.8 x 6.8 arcmin 2 field-of-view of the FORS1 camera. A great amount of fine detail is revealed, from the structures in the pronounced dust band in the equatorial plane, to many faint background galaxies that shine through the outer regions. The "Sombrero" is located in the constellation Virgo (The Virgin), at a distance of about 50 million light-years. The overall "sharpness" of this colour image corresponds to about 0.7 arcsec which translates into a resolution of about 170 light-years at that distance. About Messier 104 Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 - 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a "very faint nebula". The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy's rotation. ESO Press Photo 07c/00 ESO Press Photo 07c/00 [Preview; JPEG: 400 x 307; 59k] [Normal; JPEG: 800 x 614; 308k] [Full-Res; JPEG: 2028 x 1556; 2.3Mb] PR Photo 07c/00 has been processed to show the numerous dust bands in the central plane of the Sombrero galaxy (see the technical note below). This makes it possible to follow the spiral structure almost all the way round. The dark areas around the stars and galaxies in the field are artefacts of the image processing. This galaxy is notable for its dominant nuclear bulge , composed primarily of mature stars, and its nearly edge-on disk composed of stars, gas, and intricately structured dust. The complexity of this dust, and the high resolution of this image, is most apparent directly in front of the bright nucleus, but is also very evident as dark absorbing lanes throughout the disk. A significant fraction of the galaxy disk is even visible on the far side of the source, despite its massive bulge, cf. PR Photo 07c/00 . A large number of small and slightly diffuse sources can be seen as a swarm in the halo of Messier 104 . Most of these are globular clusters , similar to those found in our own Galaxy. Measurements reveal a steep increase in the mass-to-light ratio and increasing stellar speeds near the nucleus of Messier 104 . This is indicative of the presence of a massive black hole at the centre, estimated at about 10 9 solar masses. The radio properties of Messier 104 are unusual for a spiral galaxy - it has a variable core. The optical spectrum of the central region displays emission lines from hot gas (of the "LINER" type - Low Ionisation Nuclear Emission line Region). This points to Messier 104 harbouring a weak Active Galactic Nucleus (AGN) . Although more commonly known from the much more luminous and distant quasars and powerful radio galaxies, the weak AGN in this galaxy lies at the opposite extreme: the most likely explanation being a central black hole accreting circumnuclear matter at a slow pace. Technical information : PR Photos 07a/00 and 07b/00 are composites based on three exposures from the FORS1 instrument at VLT ANTU. They were obtained at about 6:20 hrs UT on January 30, 2000, through V-band (central wavelength 554 nm; 112 nm Full Width Half Maximum (FWHM); exposure time 120 sec; here rendered as blue),

2000-02-01

415

A herringbone bedform pattern of possible Taylor-Go??rtler type flow origin seen in sonographs  

USGS Publications Warehouse

Side-scan sonar records collected in a shallow arctic lagoon (2-2.5 m depth) reveal a herringbone pattern of current-aligned linear reflectors with branching diagonals. The major longitudinal reflectors have no detectable relief (<20 cm), are spaced 5-10 m apart, and may represent current-aligned helical cell boundaries preserved in the silty fine sand of the lagoon floor. The pattern suggests a three-dimensional flow regime of the Taylor-Go??rtler type. ?? 1979.

Toimil, L.J.; Reimnitz, E.

1979-01-01

416

Investigation of subsurface tar-sand deposits in western Kentucky  

Microsoft Academic Search

Tar sands (also referred to as asphaltic sandstones, heavy-oil deposits, or bitumen-impregnated sandstones) in W. Kentucky have been recognized as a potential mineral resource for over 100 yr. These deposits have become the subject of increasing interest as a potential petroleum resource. Previous studies have provided estimates of the potential resources of shallow mineable tar-sand deposits. These investigations have concentrated

D. A. Williams; M. C. Noger; P. J. Gooding

1982-01-01

417

Sources of relict sand on the Northeast Texas continental shelf  

E-print Network

B3 Major Subject: Oceanography SOURCES OF RELICT SAND ON THE NORTHEAST TEXAS CONTINENTAL SHELF A Thesis JEFFREY WAYNE HAWKINS Approved as to style and content by: David W. McGrail (Chairman of Committee) James Nazzll ( member ) Richard Rez... ( Nember ) Robert O. Reid (Head of Department) December 1983 AS ST PA(. f Sources ot Relict Sand on the Northeast Texas Continental shelf . ( December, 1983 ) Jeffrey Wayne Hawkins, B. A. ; Augustana College, illinois Chairman of Advisozy Committee...

Hawkins, Jeffrey Wayne

2012-06-07

418

Western tight gas sands advanced logging workshop proceedings  

SciTech Connect

An advanced logging research program is one major aspect of the Western Tight Sands Program. Purpose of this workshop is to help BETC define critical logging needs for tight gas sands and to allow free interchange of ideas on all aspects of the current logging research program. Sixteen papers and abstracts are included together with discussions. Separate abstracts have been prepared for the 12 papers. (DLC)

Jennings, J B; Carroll, Jr, H B [eds.

1982-04-01

419

Creating and maintaining a gas cap in tar sands formations  

SciTech Connect

Methods for treating a tar sands formation are disclosed herein. Methods for treating a tar sands formation may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. Pressure may be allowed to increase in an upper portion of the formation to provide a gas cap in the upper portion. At least some hydrocarbons are produced from a lower portion of the formation.

Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX); Dinkoruk, Deniz Sumnu (Houston, TX); Wellington, Scott Lee (Bellaire, TX)

2010-03-16

420

RESERVOIR STUDY OF THE CAMP SAND, HAYNESVILLE FIELD, LOUISIANA  

Microsoft Academic Search

A successful miscible flood was initiated during 1966 in a Camp Sand Unit, N. Haynesville field, Claiborne Parish, Louisiana. The Camp Sand Unit is about 3.5 miles (5.6 km) long and one mile (1.6 km) wide. Injection of a slug of enriched gas was followed by a buffer of natural gas and then by water. Over 2.4 million bbl of

J. T. Morgan; Thompson J. E

1978-01-01

421

Thermoelastic Enhancement of Damping of Sand Using Synthetic Ground Rubber  

Microsoft Academic Search

This paper examines the possibility of introducing synthetic rubber in constructed earthen systems to improve their vibration attenuation. The results of a series of controlled laboratory tests—aimed to investigate the improvement of low-strain dynamic properties of Ottawa sand by mixing ground rubber of similar size—showed a simultaneous increase in both the shear modulus and the damping ratio of the sand

Sibel Pamukcu; Suat Akbulut

2006-01-01

422

Archaeology and holocene sand dune stratigraphy on Chatham Island  

Microsoft Academic Search

Four depositional episodes based on sand deposits and the soils on them are proposed for Holocene coastal sand dunes on Chatham Island: Te Onean Depositional Episode (c. 5,000 to 2,200 years BP), Okawan Depositional Episode (c. 2,200 to 450 years BP), Kekerionean Depositional Episode (c. 450 to 150 years BP) and Waitangian Depositional Episode (c. 150 years BP to present

B. G. McFadgen

1994-01-01

423

Sanding dust from nanoparticle-containing paints: Physical characterisation  

NASA Astrophysics Data System (ADS)

Increasing use of nanoparticles in different industrial applications has raised a new potential health risk to the workers as well as to the consumers. This study investigates the particle size distributions of sanding dust released from paints produced with and without engineered nanoparticles. Dust emissions from sanding painted plates were found to consist of five size modes; three modes under 1 ?m and two modes around 1 and 2 ?m. We observed that the sander was the only source of particles smaller than 50 nm and they dominated the number concentration spectra. Mass and surface area spectra were dominated by the 1 and 2 ?m modes. Addition of nanoparticles caused only minor changes in the geometric mean diameters of the particle modes generated during sanding of two paints doped with 17 nm TiO2 and 95 nm Carbon Black nanoparticles as compared to the size modes generated during sanding a conventional reference paint. However, the number concentrations in the different size modes varied considerably in between the two NP-doped paints and the reference paint. Therefore, from a physical point of view, there may be a difference in the exposure risk during sanding surfaces covered with nanoparticle-based paints as compared to sanding conventional paints.

Koponen, I. K.; Jensen, K. A.; Schneider, T.

2009-02-01

424

Wind Enhanced Raindrop Splash Sand Transport  

NASA Astrophysics Data System (ADS)

Raindrop splash is widely accepted as an important mechanism of soil erosion (e.g. Van Dijk, Bruijnzeel, and Eisma 2003) as it can cause both particle detachment and transport. Since 1950, a number of papers have been published to identify and quantify the factors that influence splash transport (e.g. Ekern 1944; Rose 1960; Hudson 1963; Morgan 1981). More recently there has been attention focused on the combined processes of splash detachment and grain transport enhanced by the presence of wind (e.g. Erpul et al., 2009, 2008; Foulds and Warbuton 2007a, b; Cornelis et al. 2004a, 2004b; Erpul, Norton, and Gabriels 2002). However, in terms of splash transport rate estimation, these models are based on empiricism, which limits their real world applications. Therefore, the purpose of this paper is to propose a more physically based model to estimate the wind-enhanced splash transport rate. For simplicity, this model assumes the splashing occurs on a flat, sandy surface, the wind condition is steady, and the wind-raindrop- sand system has reached an equilibrium status, i.e. splash transport rate becomes constant. Raindrops become oblique to the surface due to the effect of wind. Therefore, the terminal velocity can be divided into horizontal and vertical components. When an incident raindrop hits the sandy surface, it will generate a splash crater formed by thousands of ejecting droplets. This model will not simulate the trajectory of each individual ejecting droplet; instead, it will only focus on the bulk transport rate for all the ejecting droplets within the crater. If there is no wind, the crater will be symmetrical and the bulk (net) transport is zero. Raindrop terminal horizontal and vertical velocities were obtained by applying the law of motion on a raindrop falling in a given wind field. Detachment rate was estimated from an empirical model. Average splash transport distance was obtained using the “Stokes Law”. The bulk sediment transport rate was calculated using the product of splash distance and detachment rate. Simulation results indicate that 1) raindrop terminal vertical velocity is the function of raindrop size, which is related to rainfall intensity; 2) raindrop horizontal velocity is the function of wind profile, especially the free stream velocity; 3) detachment rate is a function of soil (sand here) type and incident raindrop terminal vertical velocity; 4) average splash distance is mainly related to incident raindrop terminal horizontal velocity; 5) bulk transport rate is a function of wind velocity and rainfall intensity if ignoring the effect of soil type. Finally, scenario analysis on different wind speeds and rainfall intensities indicates that: for slow wind, synergy between wind and raindrops is more effective than wind alone; for fast wind, wind alone is more effective.

Li, B.

2010-12-01

425

Elucidating aeolian dune history from lacustrine sand records in the Lake Michigan Coastal Zone, USA  

Microsoft Academic Search

Aeolian sand in two small lakes within a Lake Michigan coastal-dune complex southwest of Holland, Michigan, provides a more detailed higher-resolution history of dune activity, during the later half of the Holocene, than do combined palaeosol and OSL ages from the dunes themselves. The sand signal from four cores within these lakes consists of visible sand laminae and invisible sand

Emily A. Timmons; Timothy G. Fisher; Edward C. Hansen; Elliott Eisaman; Trevor Daly; Michaele Kashgarian

2007-01-01

426

Evaluation of an Innovative Sand Filter for Small System Drinking Water Treatment  

EPA Science Inventory

Results of evaluation of an innovative sand filter that uses the concepts of both slow and rapid sand filtration are presented in this article. The system uses a low-cost ?Drum Sand Filter? (DSF) that consists of a 55-gallon drum filled with layers of sand of varying size. A low-...

427

Adapted by Joshua Johnson November 12, 2013 Sand Tank (1st  

E-print Network

: Sand Tank provided by the CSM Integrated Groundwater Modeling Center Food coloring Aquifer activity and show sand clay and gravel layers. Discuss how they are different. Sand Tank Procedure: 1. Inject food coloring into sand, clay and gravel layer. Allow students to predict which will move more quickly through

428

Effect of mould expansion on pattern allowances in sand casting of steel  

E-print Network

Effect of mould expansion on pattern allowances in sand casting of steel F. Peters1 , R. Voigt2 , S. Z. Ou3 and C. Beckermann*3 For steel castings produced in sand moulds, the expansion of the sand. Keywords: Steel casting, Pattern allowance, Sand expansion, Dimensional control, Casting simulation, Stress

Beckermann, Christoph

429

Alder-Frankia Symbionts Enhance the Remediation and Revegetation of Oil Sands Tailings  

Microsoft Academic Search

Extraction of petroleum from the oil sands creates lar ge quantities of oil sands process- affected water (OSPW) and tailings sand. The tailings sand has a low fertility, a low organic matter content, it is highly alkaline, compactable, and contains residual hydrocarbons, making it a very inhospitable growth environment. As the exploitation of this resource intensifies, increasing quantities of OSPW

Elisabeth Lefrançois; Ali Quoreshi; Damase Khasa; Martin Fung; Lyle G. Whyte; Sébastien Roy; Charles W. Greer

430

Laboratory measurement of saltating sand particles' angular velocities and simulation of its effect on saltation trajectory  

Microsoft Academic Search

This paper reports a laboratory observation of spin attitudes and angular velocities of saltating sand particles in wind-blown sand flux by using the high-speed and dynamic cinecamera and presents a numerical simulation to show the effect of spin on the saltating trajectories of sand particles. Experiment results show that a saltating sand particle has two basic spin attitudes, rolling spin

Li Xie; Yuquan Ling; Xiaojing Zheng

2007-01-01

431

Responses of dune mosses to experimental burial by sand under natural and greenhouse conditions  

Microsoft Academic Search

Sand movement is a predominant feature of mobile coastal and lake-shoreline sand dunes. Plants growing in these environments are able to withstand and survive periods of burial by sand. Although mosses are important dune stabilizers in temperate dunes, there are few studies focused on their response to burial by sand. In this study we examined the effects of burial by

M. Luisa Martínez; M. A. Maun

1999-01-01

432

Acidic stream mitigation by limestone sand addition  

SciTech Connect

The Town Line Run watershed comprises an area of 3,600 wooded acres. The tributaries feeding the stream consist of sandstone springs that do not contribute alkalinity to the watershed, leaving the stream susceptible to acid precipitation. This has a negative affect on Iser`s Run, a native brook trout fishery above the confluence with Town Line Run. The objective in stream liming is to improve water chemistry by increasing pH, alkalinity, and reducing acidity, aluminum, and iron. Introducing crushed limestone directly into a stream from a dump truck is an inexpensive but temporary solution to accomplish this objective. In this type of liming operation, a bed of limestone is spread down the stream channel by the momentum of the stream from the introduction point, rather than manually. Water moving across this bed dissolves the limestone, increasing the pH, alkalinity, and calcium while decreasing the acidity, iron, and aluminum concentrations of the water. The size of the limestone particles is important for this purpose because particles that are too small (<150 microns) will carried away, while particles that are too large (>1000 microns) will remain at the introduction point. Our study placed 80 tons of sand-sized limestone (85% calcite) in the stream channel at a single point. Water samples were collected monthly at the following sites (1) directly upstream of the addition site, (2) 100 yards downstream of the site, and (3) 2500 yards downstream of the site. Other sample locations include (4) upstream and (5) downstream of the Town Line Run- Iser`s Run confluence and the Casselman River upstream (6) and downstream (7) of Town Line Run. The samples were analyzed for pH. Specific conductivity, Alkalinity, Acidity, Iron, Manganese, Aluminum, and Sulfate.

Brant, D.L. [WVU National Research Center for Coal and Energy, Morgantown, WV (United States); Marich, A.J. Jr. [PA Dept. of Environmental Protection, Markleton, PA (United States); Largent, K.L. [Somerset Conservation District, Somerset, PA (United States)

1996-12-31

433

Hydrogeomorphology of the hyporheic zone: stream solute and fine particle interactions with a dynamic streambed  

USGS Publications Warehouse

Hyporheic flow in streams has typically been studied separately from geomorphic processes. We investigated interactions between bed mobility and dynamic hyporheic storage of solutes and fine particles in a sand-bed stream before, during, and after a flood. A conservatively transported solute tracer (bromide) and a fine particles tracer (5 ?m latex particles), a surrogate for fine particulate organic matter, were co-injected during base flow. The tracers were differentially stored, with fine particles penetrating more shallowly in hyporheic flow and retained more efficiently due to the high rate of particle filtration in bed sediment compared to solute. Tracer injections lasted 3.5 h after which we released a small flood from an upstream dam one hour later. Due to shallower storage in the bed, fine particles were rapidly entrained during the rising limb of the flood hydrograph. Rather than being flushed by the flood, we observed that solutes were stored longer due to expansion of hyporheic flow paths beneath the temporarily enlarged bedforms. Three important timescales determined the fate of solutes and fine particles: (1) flood duration, (2) relaxation time of flood-enlarged bedforms back to base flow dimensions, and (3) resulting adjustments and lag times of hyporheic flow. Recurrent transitions between these timescales explain why we observed a peak accumulation of natural particulate organic matter between 2 and 4 cm deep in the bed, i.e., below the scour layer of mobile bedforms but above the maximum depth of particle filtration in hyporheic flow paths. Thus, physical interactions between bed mobility and hyporheic transport influence how organic matter is stored in the bed and how long it is retained, which affects decomposition rate and metabolism of this southeastern Coastal Plain stream. In summary we found that dynamic interactions between hyporheic flow, bed mobility, and flow variation had strong but differential influences on base flow retention and flood mobilization of solutes and fine particulates. These hydrogeomorphic relationships have implications for microbial respiration of organic matter, carbon and nutrient cycling, and fate of contaminants in streams.

Harvey, J.W.; Drummond, J.D.; Martin, R.L.; McPhillips, L.E.; Packman, A.I.; Jerolmack, D.J.; Stonedahl, S.H.; Aubeneau, A.F.; Sawyer, A.H.; Larsen, L.G.; Tobias, C.R.

2012-01-01

434

Plant mixtures and monocultures on topsoiled and nontopsoiled lignite spoil in the Post Oak Savannah of Texas  

E-print Network

to be stratified clay, silty clay, and silty clay loam with the surface layer being a massive, heavy silty clay loam (Janak 1982). The'topsoil was classified as a fine sandy loam. Both topsoil and spoil resemble the Crockett series, a fine, montmorilloni- tic... to be stratified clay, silty clay, and silty clay loam with the surface layer being a massive, heavy silty clay loam (Janak 1982). The'topsoil was classified as a fine sandy loam. Both topsoil and spoil resemble the Crockett series, a fine, montmorilloni- tic...

Van Hook, Kevin

2012-06-07

435

Using coarse\\/fine manipulation with vision to place fine pitch SMD components  

Microsoft Academic Search

An experimental system that can accurately align and place SMDs (surface mount devices) on a printed circuit board is described. Features of the system are fine positioning and endpoint sensing after an IBM 7576 robot coarsely aligns the SMD to its target. Fine positioning is done using a customer-designed micropositioning device. The endpoint sensor is a single camera vision system

J. P. Baartman; A. E. Brennemann; S. J. Buckley; M. C. Moed

1989-01-01

436

College of Fine Arts Office of the Dean  

E-print Network

College of Fine Arts Office of the Dean 202 Fine Arts Building Lexington, KY 40506-0047 office: 859 257-8146 fax: 859 323-1050 College of Fine Arts Research and Creative Activity Travel Grant Guidelines For Associate and Full Professors (updated August 2013) The Dean of the College of Fine Arts will award

Hayes, Jane E.

437

College of Fine Arts Office of the Dean  

E-print Network

receive funding, please note that the "College of Fine Arts, Office of the Dean" must be acknowledgedCollege of Fine Arts Office of the Dean 202 Fine Arts Building Lexington, KY 40506-0047 office: 859 257-8146 fax: 859 323-1050 College of Fine Arts Research and Creative Activity Travel Grant Guidelines

Hayes, Jane E.

438

Potential hydrologic impacts of a tar-sand industry in 11 special tar sand areas in eastern Utah  

USGS Publications Warehouse

About 93 percent of the Nation 's estimated 30 billion barrels of crude oil in tar sand deposits is in 11 tar-sand deposits in eastern Utah that were chosen for leasing by the Federal government. The Tar Sand Triangle area, which contains about 15 billion barrels of oil, is the largest. This area and the Sunnyside and P R Springs areas contain more than three-fourths of the Utah reserves. About 88,000 acre-feet of water per year would be required for a commercial tar-sand industry producing about 365,000 barrels per day. At this rate, most of the recoverable oil would be mined within 30 years. About 22,000 acre-feet of water per year would be required for a commercial tar-sand industry producing about 83,000 barrels per day. Impacts on local hydrology would be greatest in the Tar Sand Triangle, Sunnyside, and P R Springs areas. Impacts could be minimized with proper construction of surface facilities to decrease erosion, sediment transport, and impoundment of mining and retort water. Increases in salinity of the Colorado River at Imperial Dam, Ariz.-Calif., could be about 3 milligrams per liter, with a peak of 9 milligrams per liter, for a 365 ,000-barrel-per-day industry and less than 1 milligram per liter , with a peak of 2 milligrams per liter, for an 83 ,000-barrel-per-day industry. (USGS)

Lindskov, K.L.

1983-01-01

439

Consumers Power raps big NRC fine proposal  

SciTech Connect

Consumers Power Co. of Jackson, Mich., protesting the Nuclear Regulatory Commission (NRC) fines since the Three Mile Island (TMI) accident, argues that the NRC is exceeding its own guidelines in an effort to appear more diligent. The NRC's fine for safety violations reported by Consumer Power's Palisades nuclear plant is a record high of $450,000 and nearly three times as high as those assessed against Metropolitan Edison for the TMI accident. The fine was announced shortly after NRC was criticized by the Kemeny Commission and was accompanied by a letter to all utilities operating nuclear reactors to explain the new enforcement policy. Consumers Power claims there is no evidence that the plant was operating while the violations were in effect and that the voluntary violation report was based on inference because no release of radiation could be detected. (DCK)

Not Available

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