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1

Numerical study of turbulent flow over complex aeolian dune fields: The White Sands National Monument  

NASA Astrophysics Data System (ADS)

The structure and dynamics of fully developed turbulent flows responding to aeolian dune fields are studied using large-eddy simulation with an immersed boundary method. An aspect of particular importance in these flows is the downwind migration of coherent motions associated with Kelvin-Helmholtz instabilities that originate at the dune crests. These instabilities are responsible for enhanced downward transport of high-momentum fluid via the so-called turbulent sweep mechanism. However, the presence of such structures and their role in determining the bulk characteristics of fully developed dune field sublayer aerodynamics have received relatively limited attention. Moreover, many existing studies address mostly symmetric or mildly asymmetric dune forms. The White Sands National Monument is a field of aeolian gypsum sand dunes located in the Tularosa Basin in southern New Mexico. Aeolian processes at the site result in a complex, anisotropic dune field. In the dune field sublayer, the flow statistics resemble a mixing layer: At approximately the dune crest height, vertical profiles of streamwise velocity exhibit an inflection and turbulent Reynolds stresses are maximum; below this, the streamwise and vertical velocity fluctuations are positively and negatively skewed, respectively. We evaluate the spatial structure of Kelvin-Helmholtz instabilities present in the dune field sublayer (shear length Ls and vortex spacing ?x) and show that ?x=mduneLs, where mdune?7.2 in the different sections considered (for turbulent mixing layers, 7

Anderson, William; Chamecki, Marcelo

2014-01-01

2

A numerical study of turbulent flow over complex aeolian dune fields: the White Sands National Monument  

NASA Astrophysics Data System (ADS)

The structure and dynamics of fully-developed turbulent flows responding to aeolian dune fields are studied using large-eddy simulation with an immersed boundary method. An aspect of particular importance in these flows is the downwind migration of coherent motions associated with Kelvin-Helmholtz instabilities which originate at the dune crests. These instabilities are responsible for enhanced downward transport of high momentum fluid via the so-called turbulent sweep mechanism. However, the presence of such structures and their role in determining the bulk characteristics of fully developed dune field sublayer aerodynamics has received relatively limited attention. Moreover, many existing studies address mostly symmetric or mildly asymmetric dune forms. The White Sands National Monument is a field of aeolian gypsum sand dunes located in the Tularosa Basin in southern New Mexico. Aeolian processes at the site result in a complex, anisotropic dune field. In the dune field sublayer, the flow statistics resemble a mixing layer: at approximately the dune crest height, vertical profiles of streamwise velocity exhibit an inflection and turbulent Reynolds stresses are maximum; below this, the streamwise and vertical velocity fluctuations are positively and negatively skewed, respectively. We evaluate the spatial structure of Kelvin-Helmholtz instabilities present in the dune field sublayer -- shear length, Ls, and vortex spacing, Lambda_x -- and show that Ls = m Lambda_x, where m is approximately 8 in the different sections considered (for turbulent mixing layers, 7 < m < 10, Rogers and Moser, 1994: Phys. Fluids A, 6, 903-922). These results guide discussion on the statistics of aerodynamic drag across the dunes; probability density functions of time-series of aerodynamic drag for the dunes are shown to exhibit skewness and variance much greater than values reported for turbulent boundary layer flow over an homogeneous roughness distribution. Thus, we propose that aeolian processes and dune pattern evolution is strongly influenced by the mixing layer physics in the dune field sublayer, and these physics are different to what would otherwise be predicted when using the equilibrium logarithmic law.

Anderson, W. W.; Chamecki, M.; Kocurek, G.; Mohrig, D. C.

2013-12-01

3

V-2 at White Sands  

NASA Technical Reports Server (NTRS)

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

1947-01-01

4

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

5

Ecological release in White Sands lizards  

PubMed Central

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

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

2011-01-01

6

V-2 Rocket at White Sands  

NASA Technical Reports Server (NTRS)

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

1946-01-01

7

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/...

8

White Sands, New Mexico as seen from STS-60  

NASA Technical Reports Server (NTRS)

White Sands National Monument (Park) is easily recognized in the center of this near-vertical color photograph. White Sands is the world's largest gypsum dune field. It represents an alabaster sea that covers nearly 300 square miles. At the southwest corner of the White Sands is dry lake, Lucero. In terms of cultural features the city of Alamogordo and Holloman Air Force Base can be seen with great clarity on this photograph.

1994-01-01

9

Note on Mesopheric Winds Above White Sands Missile Range.  

National Technical Information Service (NTIS)

Two high-altitude explosions above the White Sands Missile Range (WSMR), New Mexico, provided information on winds above altitudes usually attained by meteorological rockets. This note concerns the evaluation of winds from the sounds of these explosions a...

M. Diamond

1965-01-01

10

Unguided Rocket Impact Dispersion at White Sands Missile Range, New Mexico.  

National Technical Information Service (NTIS)

Impact dispersion data are presented for the following unguided sounding rockets launched from White Sands Missile Range, New Mexico, or the Utah Launch Complex, Green River, Utah, during 1965-1971: Aerobee 350, Aerobee-170, Aerobee-170A, Aerobee-150, Ath...

G. L. Dunaway M. M. Hoidale

1972-01-01

11

Trends in Gypsiferous Aerosol Downwind of White Sands, New Mexico  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

12

NASA Johnson Space Center: White Sands Test Facility  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the testing facilities and laboratories available at the White Sands Test Facility (WSTF). The mission of WSTF is to provide the expertise and infrastructure to test and evaluate spacecraft materials, components and propulsion systems that enable the safe exploration and use of space. There are nine rocket test stands in two major test areas, six altitude test stands, three ambient test stands,

Aggarwal, Pravin; Kowalski, Robert R.

2011-01-01

13

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

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

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

14

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

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

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

15

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

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

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

16

Molecular and functional basis of phenotypic convergence in white lizards at White Sands  

PubMed Central

There are many striking examples of phenotypic convergence in nature, in some cases associated with changes in the same genes. But even mutations in the same gene may have different biochemical properties and thus different evolutionary consequences. Here we dissect the molecular mechanism of convergent evolution in three lizard species with blanched coloration on the gypsum dunes of White Sands, New Mexico. These White Sands forms have rapidly evolved cryptic coloration in the last few thousand years, presumably to avoid predation. We use cell-based assays to demonstrate that independent mutations in the same gene underlie the convergent blanched phenotypes in two of the three species. Although the same gene contributes to light phenotypes in these White Sands populations, the specific molecular mechanisms leading to reduced melanin production are different. In one case, mutations affect receptor signaling and in the other, the ability of the receptor to integrate into the melanocyte membrane. These functional differences have important ramifications at the organismal level. Derived alleles in the two species show opposite dominance patterns, which in turn affect their visibility to selection and the spatial distribution of alleles across habitats. Our results demonstrate that even when the same gene is responsible for phenotypic convergence, differences in molecular mechanism can have dramatic consequences on trait expression and ultimately the adaptive trajectory.

Rosenblum, Erica Bree; Rompler, Holger; Schoneberg, Torsten; Hoekstra, Hopi E.

2009-01-01

17

Standards Development Activities at White Sands Test Facility  

NASA Technical Reports Server (NTRS)

The development of standards and standard activities at the JSC White Sands Test Facility (WSTF) has been expanded to include the transfer of technology and standards to voluntary consensus organizations in five technical areas of importance to NASA. This effort is in direct response to the National Technology Transfer Act designed to accelerate transfer of technology to industry and promote government-industry partnerships. Technology transfer is especially important for WSTF, whose longterm mission has been to develop and provide vital propellant safety and hazards information to aerospace designers, operations personnel, and safety personnel. Meeting this mission is being accomplished through the preparation of consensus guidelines and standards, propellant hazards analysis protocols, and safety courses for the propellant use of hydrogen, oxygen, and hypergols, as well as the design and inspection of spacecraft pressure vessels and the use of pyrovalves in spacecraft propulsion systems. The overall WSTF technology transfer program is described and the current status of technology transfer activities are summarized.

Baker, D. L.; Beeson, H. D.; Saulsberry, R. L.; Julien, H. L.; Woods, S. S.

2003-01-01

18

Simultaneous Ka-Band Site Characterization: Goldstone, CA, White Sands, NM, and Guam, USA  

NASA Technical Reports Server (NTRS)

To statistically characterize atmospheric effects on Ka-band links at NASA operational sites, NASA has constructed site test interferometers (STI s) which directly measure the tropospheric phase stability and rain attenuation. These instruments observe an unmodulated beacon signal broadcast from a geostationary satellite (e.g., Anik F2) and measure the phase difference between the signals received by the two antennas and its signal attenuation. Three STI s have been deployed so far: the first one at the NASA Deep Space Network Tracking Complex in Goldstone, California (May 2007); the second at the NASA White Sands Complex, in Las Cruses, New Mexico (February 2009); and the third at the NASA Tracking and Data Relay Satellite (TDRS) Remote Ground Terminal (GRGT) complex in Guam (May 2010). Two station-years of simultaneous atmospheric phase fluctuation data have been collected at Goldstone and White Sands, while one year of data has been collected in Guam. With identical instruments operating simultaneously, we can directly compare the phase stability and rain attenuation at the three sites. Phase stability is analyzed statistically in terms of the root-mean-square (rms) of the tropospheric induced time delay fluctuations over 10 minute blocks. For two years, the time delay fluctuations at the DSN site in Goldstone, CA, have been better than 2.5 picoseconds (ps) for 90% of the time (with reference to zenith), meanwhile at the White Sands, New Mexico site, the time delay fluctuations have been better than 2.2 ps with reference to zenith) for 90% of time. For Guam, the time delay fluctuations have been better than 12 ps (reference to zenith) at 90% of the time, the higher fluctuations are as expected from a high humidity tropical rain zone. This type of data analysis, as well as many other site quality characteristics (e.g., rain attenuation, infrastructure, etc.) will be used to determine the suitability of all the sites for NASA s future communication services at Ka-band.

Acosta, Roberto; Morse, Jacquelynne; Zemba, Michael; Nessel, James; Morabito, David; Caroglanian, Armen

2011-01-01

19

Wagon loads of sand blows in White County, Illinois  

USGS Publications Warehouse

Several anecdotal accounts provide compelling evidence that liquefaction occurred at several sites in Illinois during the 1811-1812 New Madrid sequence, as much as 250 km north of the New Madrid seismic zone (NMSZ). At one Wabash Valley location, sand blows are still evident near Big Prairie, Illinois, a location described in a particularly detailed and precise historic account. This account includes descriptions of substantial liquefaction (sand blows) as well as a two-mile-long east-west-trending "crack" along which two feet of south-side-down displacement occurred. An offset can no longer be seen at this location, which has been extensively farmed and plowed for decades. Field reconnaissance verifies many of the details provided in the account, however. We conducted a seismic-reflection experiment at this location and observed a modest offset in the Paleozoic strata at this location. The offset is opposite to that described in the historic account, consistent with the hypothesis that large midcontinent earthquakes occur on faults reactivated in a Holocene stress regime different from the one in which they were formed. Only two explanations can account for these observations: Either large NMSZ events triggered substantial liquefaction at distances greater than hitherto realized, or at least one large "New Madrid" event occurred significantly north of the NMSZ. We explore these possibilities and conclude that, while neither one can be ruled out, several disparate lines of evidence suggest that the 23 January 1812 "New Madrid mainshock" occurred in White County, Illinois, near the location of the mb 5.5 1968 southern Illinois earthquake and recent microearthquake activity.

Hough, S. E.; Bilham, R.; Mueller, K.; Stephenson, W.; Williams, R.; Odum, J.

2005-01-01

20

Rescue Simulation - NASA White Sands Test Facility Totally Encapsulating Suit (TES) Boot Camp  

NASA Video Gallery

The White Sands Test Facility Totally Encapsulating Suit (TES) Boot Camp prepares students to deal with normal propellant operations, emergency events, and pre-operation planning by engaging studen...

21

NASA White Sands Test Facility Totally Encapsulating Suit (TES) Boot Camp  

NASA Video Gallery

The White Sands Test Facility Totally Encapsulating Suit (TES) Boot Camp prepares students to deal with normal propellant operations, emergency events, and pre-operation planning by engaging studen...

22

NASA White Sands Test Facility Totally Encapsulating Suit (TES) Boot Camp  

NASA Video Gallery

The NASA White Sands Test Facility Totally Encapsulating Suit (TES) Boot Camp prepares students to deal with normal propellant operations, emergency events, and pre-operation planning by engaging s...

23

Overview of NASA White Sands Test Facility Composite Overwrapped Pressure Vessel Testing  

NASA Technical Reports Server (NTRS)

This viewgraph presentation examines the White Sands Test Facility testing of Composite overwrapped pressure vessel (COPV). A COPV is typically a metallic liner overwrapped with a fiber epoxy matrix. There is a weight advantage over the traditional all metal design. The presentation shows pictures of the facilities at White Sands, and then examines some of the testing performed. The tests include fluids compatibility, and Kevlar COPV. Data for the Kevlar tests are given, and an analysis is reviewed. There is also a comparison between Carbon COPVs and the Kevlar COPVs.

Greene, Nathanael; Saulsberry, Regor; Thesken, John; Phoenix, Leigh

2006-01-01

24

Annual water-resources review, White Sands Missile Range, New Mexico  

USGS Publications Warehouse

Ground-water data were collected in 1982 at White Sands Missile Range in south-central New Mexico. Depth-to-water measurements in the Post Headquarters supply wells continued to show seasonal declines. Test wells east of the Headquarters well field continue to show long-term declines as well as seasonal fluctuations. The total amount of water pumped from White Sands Missile Range supply wells was 66,226,600 gallons more in 1982 than in 1981. The difference in the specific-conductance values of the water samples collected from the Post Headquarters supply wells in the winter and summer increased in 1982. (USGS)

Cruz, R. R.

1983-01-01

25

Equatorial weathering, landform development and the formation of white sands in north western Kalimantan, Indonesia  

Microsoft Academic Search

The morphology and geochemistry of weathering profiles in Miocene granodiorites from the coastal lowlands of NW Kalimantan, Indonesia (1°N lat.), indicate long-term weathering rates, landform development and mechanisms for the formation of `white sands' found widely in valleys and depressions. Samples are analysed from convex hill, piedmont glacis, and valley slope profiles. All profiles above the saturated zone are strongly

Michael Thomas; Martin Thorp; John McAlister

1999-01-01

26

Neutron spectrum measurements at the White Sands Missile Range Fast Burst Reactor (FBR)  

Microsoft Academic Search

The White Sands Missile Range Fast Burst Reactor (FBR) is an unmoderated, unreflected bare critical assembly of the Godiva II type. The FBR is extensively used for producing a nuclear environment which stimulates the neutron portion of a nuclear weapon. Military systems are exposed to this environment for testing and analysis of their response to a nuclear weapon. The primary

H. L. Wright; J. L. Meason; J. I. Harvey

1976-01-01

27

Space radiation studies at the White Sands Missile Range Fast Burst Reactor  

NASA Technical Reports Server (NTRS)

The operation of the White Sands Missile Range Fast Burst Reactor is discussed. Space radiation studies in radiobiology, dosimetry, and transient radiation effects on electronic systems and components are described. Proposed modifications to increase the capability of the facility are discussed.

Delapaz, A.

1972-01-01

28

Unguided Rocket Impact Dispersion at White Sands Missile Range, New Mexico (September 1969).  

National Technical Information Service (NTIS)

Impact dispersion data, in tabular and graphic form are presented for 182 Aerobees, 78 Athenas, 115 Nike-boosted rockets (Nike Apache, Nike Hydac, Nike Apache Nicap, Nike Cajun, Nike Javelin) and 249 ARCAS launched from White Sands Missile Range, New Mexi...

G. L. Dunaway M. M. Hoidale

1969-01-01

29

Two Years of Simultaneous K(sub a)-Band Measurements: Goldstone, CA; White Sands, NM; and Guam, USA  

NASA Technical Reports Server (NTRS)

In order to statistically characterize the effect of the Earth's atmosphere on Ka-Band links, site test interferometers (STIs) have been deployed at three of NASA s operational sites to directly measure each site's tropospheric phase stability and rain attenuation. These STIs are composed of two antennas on a short baseline (less than 1km) that observe the same unmodulated beacon signal broadcast from a geostationary satellite (e.g., Anik F2). The STIs are used to measure the differential phase between the two received signals as well as the individual signal attenuation at each terminal. There are currently three NASA sites utilizing STIs; the Goldstone Deep Space Communications Complex near Barstow, California; the White Sands Complex in Las Cruces, New Mexico; and the Guam Remote Ground Terminal on the island of Guam. The first two sites are both located in desert regions that have highly similar climates in terms of their seasonal temperatures, average humidity, and annual rain fall (the primary factors in determining phase stability). In contrast, Guam is in a tropical region with drastically higher annual rainfall and humidity. Five station years of data have been collected in Goldstone, three in White Sands, and two in Guam, yielding two years of simultaneous data collection across all three sites. During this period of simultaneous data collection, the root-mean-square (RMS) of the time delay fluctuations stayed under 2.40 picoseconds for 90% of the time in Goldstone, under 2.07 picoseconds for 90% of the time in White Sands, and under 10.13 picoseconds for 90% of the time in Guam. For the 99th percentile, the statistics were 6.32 ps, 6.03 ps, and 24.85 ps, respectively. These values, as well as various other site quality characteristics, will be used to determine the suitability of these sites for NASA s future communication services at Ka-Band.

Acosta, Roberto J.; Zemba, M.; Morse, J.; Nessel, J.

2012-01-01

30

An Experimental Investigation of the Towing Characteristics of the Auxiliary Repair Drydock, USS White Sands ARDS1 (ex ARD 20).  

National Technical Information Service (NTIS)

The towing characteristics of the Auxiliary Repair Drydock, USS WHITE SANDS ARDS1 (ex ARD-20) are examined. Operational considerations are discussed, and a method of improving the directional stability by the addition of skegs is investigated. The stabili...

R. Knutson

1975-01-01

31

Microbial Influences on Aeolian Sulfates; A Case Study of a Dune Field at White Sands National Monument, New Mexico  

NASA Astrophysics Data System (ADS)

Similarly to martian sulfate-rich dunes, the White Sands National Monument exhibits partially different mineral signatures of dune crests and interdune areas. At the WSNM these differences are caused by diagenetic processes and by biological activity.

Glamoclija, M.; Steele, A.; Fogel, M. L.

2011-03-01

32

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

33

Analysis of the Dryden Wet Bulb GLobe Temperature Algorithm for White Sands Missile Range  

NASA Technical Reports Server (NTRS)

In locations where workforce is exposed to high relative humidity and light winds, heat stress is a significant concern. Such is the case at the White Sands Missile Range in New Mexico. Heat stress is depicted by the wet bulb globe temperature, which is the official measurement used by the American Conference of Governmental Industrial Hygienists. The wet bulb globe temperature is measured by an instrument which was designed to be portable and needing routine maintenance. As an alternative form for measuring the wet bulb globe temperature, algorithms have been created to calculate the wet bulb globe temperature from basic meteorological observations. The algorithms are location dependent; therefore a specific algorithm is usually not suitable for multiple locations. Due to climatology similarities, the algorithm developed for use at the Dryden Flight Research Center was applied to data from the White Sands Missile Range. A study was performed that compared a wet bulb globe instrument to data from two Surface Atmospheric Measurement Systems that was applied to the Dryden wet bulb globe temperature algorithm. The period of study was from June to September of2009, with focus being applied from 0900 to 1800, local time. Analysis showed that the algorithm worked well, with a few exceptions. The algorithm becomes less accurate to the measurement when the dew point temperature is over 10 Celsius. Cloud cover also has a significant effect on the measured wet bulb globe temperature. The algorithm does not show red and black heat stress flags well due to shorter time scales of such events. The results of this study show that it is plausible that the Dryden Flight Research wet bulb globe temperature algorithm is compatible with the White Sands Missile Range, except for when there are increased dew point temperatures and cloud cover or precipitation. During such occasions, the wet bulb globe temperature instrument would be the preferred method of measurement. Out of the 30 dates examined, 23 fell under the category of having good accuracy.

LaQuay, Ryan Matthew

2011-01-01

34

Sand  

NSDL National Science Digital Library

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

35

Depleted uranium investigation at missile impact sites in White Sands Missile Range  

SciTech Connect

An investigation for residual depleted uranium was conducted at Pershing missile impact sites on the White Sands Missile Range. Subsurface core soil samples were taken at Chess, Salt Target, and Mine Impact Sites. A sampling pump was installed in a monitoring well at Site 65 where a Pershing earth penetrator was not recovered. Pumping tests and water samples were taken at this site. Chess Site, located in a gypsum flat, was the only location showing elevated levels of depleted uranium in the subsurface soil or perched groundwater. Small fragments can still be found on the surface of the impact sites. The seasonal flooding and near surface water has aided in the movement of surface fragments.

Van Etten, D.M.; Purtymun, W.D.

1994-01-01

36

ICESat Calibration and Validation Experiments at White Sands, New Mexico, 2003-2010  

NASA Astrophysics Data System (ADS)

The Center for Space Research (CSR) at the University of Texas at Austin has operated a primary site for ICESat cal/val activities near the White Sands Space Harbor (WSSH) area of the White Sands Missile Range, NM. This site was chosen for both geophysical (flat, reflective) and logistical (domestic, secure site) reasons. Before launch in 2003, a several-hundred-meter-scale grid comprised of hundreds of numbered PVC base-plates was installed at the chosen site to permanently mark the locations of various pieces of experiment hardware. In summary, CSR has supported four primary types of experiments at the cal/val site: (1) a permanent grid of laser retro-reflectors (corner cube reflectors) placed on top of poles of various known heights and collocated with 25 of the base plates, in use for the duration of the mission, (2) a set of computer-monitored position and timing detectors utilized for cal/val during the first three years of the project, (3) several camera-equipped aircraft flyovers of the area designed to capture images of the green and infrared footprints on the surface at the precise time of ICESat overflights, (4) elevation comparisons between the ICESat data and a high-resolution (1 m) DEM derived via small-footprint airborne lidar collections in 2003 and 2007. The experiments at WSSH were targeted by the ICESat spacecraft approximately four times per campaign, making this cal/val site one of the most sampled locations in the world. This presentation will chronicle the extensive collection of ICESat and experimental data collected at WSSH from 2003 to 2010.

Schutz, B. E.; Urban, T. J.

2010-12-01

37

Complex resistivity signatures of ethanol in sand-clay mixtures  

USGS Publications Warehouse

We performed complex resistivity (CR) measurements on laboratory columns to investigate changes in electrical properties as a result of varying ethanol (EtOH) concentration (0% to 30% v/v) in a sand–clay (bentonite) matrix. We applied Debye decomposition, a phenomenological model commonly used to fit CR data, to determine model parameters (time constant: ?, chargeability: m, and normalized chargeability: mn). The CR data showed a significant (P ? 0.001) time-dependent variation in the clay driven polarization response (~ 12 mrad) for 0% EtOH concentration. This temporal variation probably results from the clay–water reaction kinetics trending towards equilibrium in the sand–clay–water system. The clay polarization is significantly suppressed (P ? 0.001) for both measured phase (?) and imaginary conductivity (??) with increasing EtOH concentration. Normalized chargeability consistently decreases (by up to a factor of ~ 2) as EtOH concentration increases from 0% to 10% and 10 to 20%, respectively. We propose that such suppression effects are associated with alterations in the electrical double layer (EDL) at the clay–fluid interface due to (a) strong EtOH adsorption on clay, and (b) complex intermolecular EtOH–water interactions and subsequent changes in ionic mobility on the surface in the EDL. Changes in the CR data following a change of the saturating fluid from EtOH 20% to plain water indicate strong hysteresis effects in the electrical response, which we attribute to persistent EtOH adsorption on clay. Our results demonstrate high sensitivity of CR measurements to clay–EtOH interactions in porous media, indicating the potential application of this technique for characterization and monitoring of ethanol contamination in sediments containing clays.

Personna, Yves Robert; Slater, Lee; Ntarlagiannis, Dimitrios; Werkema, Dale; Szabo, Zoltan

2013-01-01

38

100 Megacycle VHF Re-Entry Radar for Stallion Site, White Sands Missile Range, AN/TPQ-20.  

National Technical Information Service (NTIS)

A 100-megacycle, 1-megawatt, variable pulse width (1, 2.5 and 5 microseconds) radar, the AN/TPQ-20, was installed at the Stallion Site, White Sands, New Mexico, for the purpose of viewing and photographically recording A-scope displays of the Athena test ...

1964-01-01

39

Monte Carlo calculations of the neutron environment produced by the White Sands missile range fast burst reactor  

Microsoft Academic Search

The Monte Carlo method is used to calculate the leakage neutron spectrum of the White Sands missile range fast burst reactor. The leakage spectrum is used as the source spectrum for further calculations, which are directly compared to experimental data. The calculated spectrum differs somewhat from the experimentally measured shape, particularly in the 3- to 6- MeV region. The calculated

T. M. Flanders; M. H. Sparks

1989-01-01

40

Emplacement and dewatering of the world's largest exposed sand injectite complex  

NASA Astrophysics Data System (ADS)

Sandstone injectites form by up or down-section flow of a mobilized sand slurry through fractures in overlying rock. They act as reservoirs and high-permeability conduits through lower permeability rock in hydrocarbon systems. The Yellow Bank Creek Complex, Santa Cruz County, California is the largest known exposure of a sandstone injectite in the world. The complex contains granular textures that record processes of sand slurry flow, multiple pore fluids, and dewatering after emplacement. The injection was initially mobilized from a source containing both water and hydrocarbons. The water-sand slurry reached emplacement depth first, due to lower fluid viscosity. As the sand slurry emplaced, the transition from slurry flow to pore water percolation occurred. This transition resulted in preferred flow channels ˜6 mm wide in which sand grains were weakly aligned (laminae). The hydrocarbon-sand slurry intruded the dewatering sands and locally deformed the laminae. Compaction of the injectite deposit and pore fluid escape caused spaced compaction bands and dewatering pipes which created convolutions of the laminae. The hydrocarbon-rich sand slurry is preserved today as dolomite-cemented sand with oil inclusions. The laminae in this injectite are easily detected due to preferential iron oxide-cementation of the well-aligned sand laminae, and lack of cement in the alternating laminae. Subtle textures like these may develop during sand flow and be present but difficult to detect in other settings. They may explain permeability anisotropy in other sand deposits.

Sherry, Timothy J.; Rowe, Christie D.; Kirkpatrick, James D.; Brodsky, Emily E.

2012-08-01

41

Permeability estimating from complex resistivity measurement of shaly sand reservoir  

NASA Astrophysics Data System (ADS)

Permeability is a key parameter associated with the subsurface production and injection. This paper introduces a new method which uses the complex resistivity of rock to estimate permeability in petroleum reservoirs. Complex resistivity measurements were carried out on 53 shaly sand samples from Daqing Oil Filed with a wide variation in permeability and porosity in the frequency range from 100 Hz to 20 MHz using a four-electrode technique. This paper investigates the relationship between the complex resistivity measurements and the permeabilities of the samples. The imaginary part of the complex impedance shows a power-law relation to the frequency ranges from 100 Hz to 1.5 kHz. The results show that permeability can be estimated well with expressions of the form of A . ?B . ?C, where ? is the slope of the bilogarthmic plot of the imaginary part versus frequency, ? is the porosity, A, B and C are constants. The salinity of NaCl has little influence of the slope in the range of 1-10 g l-1. The isovalue maps of the error factor ?, which show substantial regions of near-minimum values of ?, are used to analyse the behaviour of ? with the change of the exponents B and C. The permeability estimation is more sensitive to the changes of the slopes than the porosity. The slope and the porosity are not completely independent. The slope is the decisive parameter for the estimation of the permeability. The additional use of the porosity improves the formula fit to the data significantly.

Tong, Maosong; Tao, Honggen

2008-05-01

42

Modeling grain size variations of aeolian gypsum deposits at White Sands, New Mexico, using AVIRIS imagery  

USGS Publications Warehouse

Visible and Near-Infrared (VNIR) through Short Wavelength Infrared (SWIR) (0.4-2.5????m) AVIRIS data, along with laboratory spectral measurements and analyses of field samples, were used to characterize grain size variations in aeolian gypsum deposits across barchan-transverse, parabolic, and barchan dunes at White Sands, New Mexico, USA. All field samples contained a mineralogy of ?????100% gypsum. In order to document grain size variations at White Sands, surficial gypsum samples were collected along three Transects parallel to the prevailing downwind direction. Grain size analyses were carried out on the samples by sieving them into seven size fractions ranging from 45 to 621????m, which were subjected to spectral measurements. Absorption band depths of the size fractions were determined after applying an automated continuum-removal procedure to each spectrum. Then, the relationship between absorption band depth and gypsum size fraction was established using a linear regression. Three software processing steps were carried out to measure the grain size variations of gypsum in the Dune Area using AVIRIS data. AVIRIS mapping results, field work and laboratory analysis all show that the interdune areas have lower absorption band depth values and consist of finer grained gypsum deposits. In contrast, the dune crest areas have higher absorption band depth values and consist of coarser grained gypsum deposits. Based on laboratory estimates, a representative barchan-transverse dune (Transect 1) has a mean grain size of 1.16 ??{symbol} (449????m). The error bar results show that the error ranges from - 50 to + 50????m. Mean grain size for a representative parabolic dune (Transect 2) is 1.51 ??{symbol} (352????m), and 1.52 ??{symbol} (347????m) for a representative barchan dune (Transect 3). T-test results confirm that there are differences in the grain size distributions between barchan and parabolic dunes and between interdune and dune crest areas. The t-test results also show that there are no significant differences between modeled and laboratory-measured grain size values. Hyperspectral grain size modeling can help to determine dynamic processes shaping the formation of the dunes such as wind directions, and the relative strengths of winds through time. This has implications for studying such processes on other planetary landforms that have mineralogy with unique absorption bands in VNIR-SWIR hyperspectral data. ?? 2006 Elsevier B.V. All rights reserved.

Ghrefat, H. A.; Goodell, P. C.; Hubbard, B. E.; Langford, R. P.; Aldouri, R. E.

2007-01-01

43

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

44

Response of vegetation stability and groundwater depth to spatial variability in sediment transport; White Sands National Monument, New Mexico  

NASA Astrophysics Data System (ADS)

Spatial variability in sediment transport can drive changes in dune morphology and vegetation cover across desert dunefields. Due to the complex interaction of vegetation with both water table dynamics and the soil-salt balance a discontinuous ecosystem response may exist. A theoretical model predicts that salt-vegetation feedback can lead to two stable states; one with sparse or no vegetation cover and a shallow brackish water table, and another with dense vegetation and a deep, fresh water table (Runyan and D'Odorico, 2010). Results presented here suggest that both stable states are present at White Sands National Monument, New Mexico - a gypsum dune field with a shallow, saline groundwater table - as actively-migrating barchan dunes abruptly transition to stable, vegetated parabolic forms. Vertical profiles of soil salinity, soil moisture, and depth to groundwater table were measured across the barchan-parabolic transition. Groundwater depth drops from ~0.5 m to ~1 m across this transition, likely a response to increasing transpiration. Salinity is uniform with depth in the unvegetated dunes; parabolics with dense vegetation exhibit a strong partitioning of salts.. Groundwater salinity drops by more than an order of magnitude, while there is a spike in soil salinity at the surface; consistent with model predictions. The spatial transition in dune-plant stability may therefore be applied to understand temporal shifts in dune field stability that may result from environmental change.

Masteller, C.; Jerolmack, D. J.; Bhattachan, A.

2012-12-01

45

Narrowband Angular Reflectance Properties of the Alkali Flats at White Sands, New Mexico  

NASA Technical Reports Server (NTRS)

Results from helicopter measurements of the angular properties of surface reflectance for the alkali flats regions of the White Sands Missile Range are presented for the wavelength interval of 0.4 to 0.85 microns. This work was performed to allow accurate radiative transfer calculations over the region. Detailed tables and interpolation equations are given that permit other investigators to perform satellite calibrations over the alkali flats site. The effects of wavelength and soil moisture on narrowband angular reflectance are also investigated. Although there is a spectral variation in surface albedo, there is little spectral effect in Anisotropic Factor except in the forward scattering peak at solar zenith angles greater than 60 deg. The magnitude of the forward-scattering peak is also sensitive to soil moisture, with wet conditions causing a larger peak. The significance of this result is that angular reflectance properties at the center of the alkali flats usually will be different than those at the flats edge because moisture differences typically exist.

Whitlock, Charles H.; LeCroy, Stuart R.; Wheeler, Robert J.

1994-01-01

46

Potential for substitution of geothermal energy at domestic defense installations and White Sands Missile Range  

SciTech Connect

Geothermal resources that might provide substitute energy at any of 76 defense installations are identified and evaluated. The geologic characteristics and related economics of potential geothermal resources located at or near the 76 installations were estimated. The geologic assessment identified 18 installations with possible geothermal resources and 4 Atlantic Coastal Plain resource configurations that represented the alternatives available to East Coast bases. These 18 locations and 4 resource configurations, together with 2 possible resources at the White Sands Missile Range and a potential resource at Kings Bay, Georgia, were examined to determine the relative economics of substituting potential geothermal energy for part or all of the existing oil, gas, and electrical energy usage. Four of the military installations - Mountain Home, Norton, Hawthorne, and Sierra - appear to be co-located with possible geothermal resources which, if present, might provide substitute energy at or below current market prices for oil. Six additional locations - Ellsworth, Luke, Williams, Bliss, Fallon, and Twentynine Palms - could become economically attractive under certain conditions. No geothermal resource was found to be economically competitive with natural gas at current controlled prices. Generation of electric power at the locations studied is estimated to be uneconomic at present.

Bakewell, C.A.; Renner, J.L.

1982-01-01

47

Development of CFC-Free Cleaning Processes at the NASA White Sands Test Facility  

NASA Technical Reports Server (NTRS)

The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-113- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. The presentation will include the findings of investigations of aqueous cleaning and verification processes that are based on a draft of a proposed NASA Kennedy Space Center (KSC) cleaning procedure. Verification testing with known contaminants, such as hydraulic fluid and commonly used oils, established correlations between nonvolatile residue and CFC-113. Recoveries ranged from 35 to 60 percent of theoretical. WSTF is also investigating enhancements to aqueous sampling for organics and particulates. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon-225 (HCFC-225), tert-butylmethylether, and n-Hexane was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC-113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autoignition and liquid oxygen mechanical impact testing.

Beeson, Harold; Kirsch, Mike; Hornung, Steven; Biesinger, Paul

1995-01-01

48

The coupling of gravity waves and turbulence at White Sands, New Mexico, from VHF radar observations  

SciTech Connect

Doppler spectra taken with the VHF Doppler radar at White Sands Missile Range are used to describe the winds and turbulence for 10 days in March-April 1991. The large power aperture product of this radar provides excellent data coverage in 150-m layers over the entire height range used, about 5-20 km. The results show that gravity-wave activity and small-scale turbulence are significantly enhanced at all levels during times when wind speeds in the troposphere, near 5.6 km (about 500 hPa), are strong. Largest enhancements are found in the lower stratosphere, near 16-18 km, where the mean log C[sub n][sup 2] is increased by over 10 dB during times of strong winds at low levels. Mean winds, wind shears, and static stability in the lower stratosphere were found to be nearly the same, regardless of wind speeds at low levels. The authors conclude that the enhanced turbulence is due to an effect not described by the local background wind and static stability, and suggest that this effect is upward-propagating gravity waves launched in the troposphere during the periods of strong winds. 16 refs., 9 figs., 2 tabs.

Nastrom, G.D. (St. Cloud State Univ., MN (United States)); Eaton, F.D. (Army Atmospheric Sciences Lab., White Sands Missile Range, NM (United States))

1993-01-01

49

Vanadium and nickel complexes in the Alberta oil sands  

SciTech Connect

The nature, distribution and mode of association of V and Ni complexes in the Alberta oil-sand bitumens were investigated using neutron activation analysis (NAA), ultra-violet spectroscopy (UV), liquid chromatography, and mass spectrometry (El-MS). The Athabasca, Peace River and Cold Lake bitumens were fractionated into three soluble extracts and an asphaltene solid. All the V in the extracts was present as vanadyl porphyrin but only a small fraction of the Ni is porphyrinic. The vanadyl porphyrin content of the Athabasca bitumen is 9.52 ..mu..g/g (Peace River: 92 ..mu..g/g; Cold Lake 77 ..mu..g/g) corresponding to 47% of the total V in the bitumen (51% and 40% of the Peace River and Cold Lake respectively) the remaining still associated strongly in the asphaltenes. All five types of porphyrins were present as homologous series with carbon numbers ranging from C/sub 27/-C/sub 40/. The maxima occur at C/sub 32/ for DPEP series, C/sub 29/-C/sub 32/ for etio and C/sub 28/ for the diDPEP, rhodo etio and rhodo DPEP. The relative abundance was in the following order: DPEP > etio > diDPEP > rhodo-etio > rhodo-DPEP. The DPEP/other porphyrin ratios (etio, di-DPEP, etc.), in the bitumen extracts are similar and decrease in the order: Athabasca > Peace River > Cold Lake. The results confirm that biodgradation has no effect on porphyrin distributions and that the bitumens are related geochemically.

Strong, D.

1986-01-01

50

Climatological assessment of airblast propagations from explosion tests at White Sands Missile Range  

SciTech Connect

Atmospheric acoustic refraction, by upper air temperature and wind strata, may duct and focus explosion airblast waves, sometimes causing nuisance level damages at several times the normal distances. Large explosion tests at White Sands Missile Range may thus threaten window damage, with possible hazard from falling glass, in various surrounding communities. To establish what explosion yields may be reasonably contemplated (with acceptable delays) and the best time of year for these tests, a climatological assessment has been prepared from five years of upper air weather observations made at the Albuquerque and El Paso airports. Each twice-daily radiosonde balloon observation from each station was analyzed to show the refracting sound velocity versus height structure for all directions, the attenuating or amplifying effect on the yield-dependent explosion airblast wave, and the blast overpressure expected at each incremental area of a polar coordinate grid out to 325 km distance. It was assumed that tests would be conducted near the warmest time of the day. Population census data allowed an estimation of the number of window panes exposed in each area. A relationship between overpressure and window breakage probability was then used to calculate the expected damage from a test under the observed weather condition. Assuming that 25 broken windows could be accepted, each day was categorized as good, bad, or marginal. Climatological results are shown in various formats for the occurrences of these categories. The broad conclusions are: The best season for testing is from may through September (based on this single test consideration). In summer, there should be few delays for 500 ton HE equivlent explosions, but about a 40% likelihood of not firing 8 kt HE on a given day, and very little chance of ever firing 50 kt HE. 24 refs., 15 figs., 10 tabs.

Reed, J.W.

1986-08-01

51

The Holocene History of the White Sands Dune Field and the influences of Climate on Eolian Deflation and Playa Lakes  

NASA Astrophysics Data System (ADS)

White Sands National Monument is the largest gypsum dune field in the world. The dunes have formed downwind of a 20-m-deep, 19-km-wide deflation basin containing large playa lakes. Today, the gypsum sand is derived from the edge of the deflation basin, next to the dune field, rather than the alkali flat and playa lakes where gypsum crystals are forming. Three erosional shorelines mark wetter episodes when playa lakes formed in the deflation basin. The youngest shoreline is forming today around Lake Lucero playa. The oldest shoreline, termed L1 is degraded and probably formed at the Pleistocene-Holocene transition. Deflation from the L1 to the L2 shoreline cut through Pleistocene bedded evaporites and probably marks initiation of the dune field. This event was before 5,840 years BP, based on radiocarbon in a lake dammed by the dunes. This reinforces an evolving consensus that episodes of deflation have characterized desert basins in the southwestern United States. Regional deflation events have been dated at 7,000 years and 4,000 years BP. The shorelines in the deflation basin imply that the White Sands dune field was created in short episodes and the modern dune field may not represent conditions active during expansion of the dune sea. >http://www.geo.utep.edu/Faculty_Staff/langford.html

Langford, R. P.

2001-12-01

52

Long term geological record of a global deep subsurface microbial habitat in sand injection complexes  

PubMed Central

There is extensive evidence from drilling into continental margins for microbial colonization of a deep biosphere. However it is difficult to prove deep biosphere activity in the geological record, where evidence for life is dominated by the remains of organic matter buried after deposition at the surface. Nevertheless we propose that natural injections of sand into muddy strata at continental margins represent an excellent habitat opportunity for deep microbial activity down to several kilometres' present day depth. Sulphur isotope data for iron sulphides precipitated soon after injection indicate consistent microbial sulphate reduction through the geological record. The complexes are favourable sites for colonization, because high permeability and extensive sand/mud interface allow ready availability of electron donors and nutrients. The measured examples of iron sulphide in injected sands extend back to the Proterozoic, and show that injected sand complexes have been a long-term environment for deep subsurface microbial colonization.

Parnell, John; Boyce, Adrian J.; Hurst, Andrew; Davidheiser-Kroll, Brett; Ponicka, Joanna

2013-01-01

53

Monte Carlo calculations of the neutron environment produced by the White Sands missile range fast burst reactor  

SciTech Connect

The Monte Carlo method is used to calculate the leakage neutron spectrum of the White Sands missile range fast burst reactor. The leakage spectrum is used as the source spectrum for further calculations, which are directly compared to experimental data. The calculated spectrum differs somewhat from the experimentally measured shape, particularly in the 3- to 6- MeV region. The calculated spectra have a higher spectral index (fluence{gt}10 keV/fluence{gt}3 MeV) than the experimentally determined spectra. Generally, the two methods of determining the spectra appear to be in reasonable agreement.

Flanders, T.M.; Sparks, M.H. (White Sands Missile Range, Nuclear Effects Lab., White Sands, NM (US))

1989-11-01

54

Dust Plume Modeling from Ranges and Maneuver Areas on Fort Bliss and the White Sands Missile Range: Final Report  

SciTech Connect

The potential for air quality impacts from heavy mechanized vehicles operating on and between the unpaved main supply routes at Fort Bliss and White Sands Missile Range was investigated. This report details efforts by the staff of Pacific Northwest National Laboratory for the Fort Bliss Directorate of Environment in this investigation. Dust emission and dispersion from typical move-out activities occurring on the installations were simulated using the atmospheric modeling system DUSTRAN. Major assumptions associated with designing the modeling scenarios are summarized and results of simulations conducted under these assumptions are presented for four representative meteorological periods.

Chapman, Elaine G.; Barnard, James C.; Rutz, Frederick C.; Pekour, Mikhail S.; Rishel, Jeremy P.; Shaw, William J.

2009-05-04

55

Characterization of oil sands mineral components and clay-organic complexes  

SciTech Connect

Differences in oil sands processibility and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with product. The nature of these complexes has been studied with nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM) as well as other techniques such as thermogravimetric analysis. The relationship of these measurements to processibility and the relevance of conventional oil sands structural modes are discussed.

Axelson, D.E.; Mikula, R.J.

1988-06-01

56

IR Characterization of BiPropellant Reaction Control Engines During Auxiliary Propulsion Systems Tests at NASA's White Sands Test Facility In Las Cruces, New Mexico  

Microsoft Academic Search

This paper describes the application of a FLIR Systems A40M infrared (IR) digital camera for thermal monitoring of a Liquid Oxygen (LOX) and Ethanol bi-propellant Reaction Control Engine (RCE) during Auxiliary Propulsion System (APS) testing at the National Aeronautics & Space Administration's (NASA) White Sands Test Facility (WSTF) near Las Cruces, New Mexico. Typically, NASA has relied mostly on the

Elizabeth Holleman

57

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 3. A new species of Aleptina Dyar, 1902 (Lepidoptera, Noctuidae, Amphipyrinae, Psaphidini)  

PubMed Central

Abstract In 2006 the US National Park Service initiated a long-term study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico. Aleptina arenaria sp. n., described here, was discovered in 2008, the second year of the study. The adult moths and male and female genitalia are illustrated.

Metzler, Eric H.; Forbes, Gregory S.

2011-01-01

58

Characterization of oil sands mineral components and clay-organic complexes  

SciTech Connect

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailing as well as carry over of water and mineral matter with the product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as well as with other techniques such as interfacial tension measurements.

Axelson, D.E.; Mikula, R.J.; Potoczny, Z.M. (CRL, Fuel Processing Lab., CANMET, Energy, Mines and Resources Canada, P.O. Bag 1280, Devon, Alberta, T0C 1E0 (CA))

1989-01-01

59

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

PubMed

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

Dong, Wenming; Wan, Jiamin

2014-06-17

60

White organic light-emitting diodes with Zn-complexes.  

PubMed

This paper reviews OLEDs fabricated using Zn-complexes. Zn(HPB)2, Zn(HPB)q, and Zn(phen)q were synthesized as new electroluminescence materials. The electron affinity (EA) and ionization potential (IP) of Zn complexes were also determined and devices were characterized. Zn complexes such as Zn(HPB)2, Zn(HPB)q, and Zn(phen)q were found to exhibit blue and yellow emissions with wavelengths of 455, 532, and 535 nm, respectively. On the other hand, Zn(HPB)2 and Zn(HPB)q were applied as hole-blocking materials. As a result, the OLED efficiency by using Zn(HPB)2 as a hole-blocking material was improved. In particular, the OLED property of Zn(HPB)2 was found to be better than that of Zn(HPB)q. Moreover, Zn(phen)q was used as an electron-transporting material and compared with Alq3. The performance of the device with Zn(phen)q as an electron-transporting material was improved compared with Alq3-based devices. The Zn complexes can possibly be used as hole-blocking and electron-transporting materials in OLED devices. A white emission was ultimately realized from the OLED devices using Zn-complexes as inter-layer components. PMID:24749410

Kim, Dong-Eun; Shin, Hoon-Kyu; Kim, Nam-Kyu; Lee, Burm-Jong; Kwon, Young-Soo

2014-02-01

61

Objective evaluation of colour variation in the sand-burrowing beetle Chaerodes trachyscelides White (Coleoptera: Tenebrionidae) by instrumental determination of CIELAB values  

Microsoft Academic Search

The objective evaluation of the different colours of individual sand-burrowing beetles Chaerodes trachyscelides White illustrates that instrumental techniques may replace visual assessments and subjective descriptions of colour variation. Colour measurements based on the principles established by the Commission Intemationale d'Eclairage (CIE) provide quantitative specifications of colours as their coordinates in the 1976 CIE L*,a*,b* (CIELAB) uniform colour space. The established

A. C. Harris; I. L. Weatherall

1990-01-01

62

CYP1A induction and blue sac disease in early life stages of white suckers (Catostomus commersoni) exposed to oil sands.  

PubMed

The objectives of this study were to evaluate the influence of natural oil sands on the early developmental stages of white sucker (Catostomus commersoni) and to determine whether biochemical responses in this species were similar to native fish caught in the Athabasca Oil Sands area. Early life stage (ELS) sediment toxicity tests were conducted using controls, reference sediments, natural oil sands, and industrially contaminated (wastewater pond) sediments collected from sites along the Athabasca River, Alberta (Canada). Eggs and larvae were observed for mortality, hatching, deformities, growth, and cytochrome P-4501A (CYP1A) activity using immunohistochemistry. E-Nat-, S-Nat-, and wastewater pond sediment-exposed groups showed significant premature hatching, reduced growth, and exposure-dependent increases in ELS mortality and larval malformations relative to controls. The most common larval deformities included edemas (pericardial, yolk sac, and subepidermal), hemorrhages, and spinal defects. Juveniles exposed to oil sands and wastewater pond sediments (96 h) demonstrated significantly increased 7-ethoxyresorufin-O-deethylase (EROD) activity (30- to 50-fold) as compared to controls. Reference sediment-exposed groups and water controls demonstrated reliable embryo and larval survival, minimal malformations, and negligible CYP1A staining. These observed signs of blue sac disease (ELS mortality, malformations, growth reductions, CYP1A activity induction) may produce deleterious reproductive effects in natural fish populations exposed to oil sands mixtures. PMID:16728374

Colavecchia, Maria V; Hodson, Peter V; Parrott, Joanne L

2006-05-01

63

Airflow and sand transport variations within a backshore–parabolic dune plain complex: NE Graham Island, British Columbia, Canada  

Microsoft Academic Search

Onshore aeolian sand transport beyond the beach and foredune is often overlooked in the morphodynamics and sediment budgets of sandy coastal systems. This study provides detailed measurements of airflow, sand transport (via saltation and modified suspension), vegetation density, and surface elevation changes over an extensive (325×30 m) “swath” of a backshore foredune–parabolic dune plain complex. Near-surface (30 cm) wind speeds

Jeffrey L. Anderson; Ian J. Walker

2006-01-01

64

Analysis of the NASA White Sands Test Facility (WSTF) Test System for Friction-Ignition of Metallic Materials  

NASA Technical Reports Server (NTRS)

Friction is a known ignition source for metals in oxygen-enriched atmospheres. The test system developed by the NASA White Sands Test Facility in response to ASTM G-94 has been used successfully to determine the relative ignition from friction of numerous metallic materials and metallic materials pairs. These results have been ranked in terms of a pressure-velocity product (PV) as measured under the prescribed test conditions. A high value of 4.1(exp 8) watts per square meter for Inconel MA 754 is used to imply resistance to friction ignition, whereas a low value of 1.04(exp 8) watts per square meter for stainless steel 304 is taken as indicating material susceptible to friction ignition. No attempt has been made to relate PV values to other material properties. This work reports the analysis of the WSTF friction-ignition test system for producing fundamental properties of metallic materials relating to ignition through friction. Three materials, aluminum, titanium, and nickel were tested in the WSTF frictional ignition instrument system under atmospheres of oxygen or nitrogen. Test conditions were modified to reach a steady state of operation, that is applied, the force was reduced and the rotational speed was reduced. Additional temperature measurements were made on the stator sample. The aluminum immediately galled on contact (reproducible) and the test was stopped. Titanium immediately ignited as a result of non-uniform contact of the stator and rotor. This was reproducible. A portion of the stator sampled burned, but the test continued. Temperature measurements on the stator were used to validate the mathematical model used for estimating the interface (stator/rotor) temperature. These interface temperature measurements and the associate thermal flux into the stator were used to distinguish material-phase transitions, chemical reaction, and mechanical work. The mechanical work was used to analyze surface asperities in the materials and to estimate a coefficient of fiction. The coefficient of fiction was analyzed in terms of material properties that is, hardness, Young's modulus and elasticity/plasticity of the material.

Shoffstall, Michael S.; Wilson, D. Bruce; Stoltzfus, Joel M.

2000-01-01

65

Tuberous sclerosis complex and Wolff-Parkinson-White syndrome  

PubMed Central

This report highlights the association between tuberous sclerosis and Wolff-Parkinson-White syndrome. Ten patients with concurrent diagnoses of Wolff-Parkinson-White syndrome and tuberous sclerosis were identified. Wolff-Parkinson-White syndrome presented early in life, nine cases being diagnosed in the first year. Eight of the 10 cases were male. In eight cases, the syndrome was associated with supraventricular tachycardias, and in nine with cardiac rhabdomyomata. One child died from cardiac failure secondary to obstruction of the left ventricular outflow tract by a rhabdomyoma. Five of nine survivors showed resolution of Wolff-Parkinson-White syndrome on follow up. The accessory pathway was localised in nine patients from surface electrocardiograms: six children had left sided pathways and three had right sided pathways.??

O'Callaghan, F; Clarke, A; Joffe, H; Keeton, B; Martin, R; Salmon, A; Thomas, R; Osborne, J

1998-01-01

66

Impacts of bridging complexation on the transport of surface-modified nanoparticles in saturated sand  

NASA Astrophysics Data System (ADS)

The transport of polyacrylic acid capped cadmium telluride (CdTe) quantum dots (QDs), carboxylate-modified latex (CML), and bare silica nanoparticles (NPs) was studied in packed columns at various electrolyte concentrations and cation types. The breakthrough curves (BTCs) of QDs and CML particles in acid-treated Accusand showed significant amounts of increasing deposition with 0.5, 1, and 2 mM Ca2+, but only minute deposition at 50 and 100 mM Na+. Negligible QD and CML deposition occurred at 2 mM Ca2+ in columns packed with ultrapure quartz sand that was similar in size to the Accusand. These observations are not consistent with interpretations based on Derjaguin-Landau-Verwey-Overbeek (DLVO) calculations of interaction energies. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis demonstrated that there were regions on the acid-treated Accusand covered with small amounts of clay that were absent on the ultrapure quartz sand. A salt cleaning method was therefore used to remove the clay from the acid-treated Accusand. The BTCs of QDs and CML in this acid + salt treated Accusand exhibited much less deposition at any given Ca2+ concentration compared to those obtained from the acid-treated sand. SEM images showed that most of the QD deposited in acid-treated Accusand occurred on clay surfaces. Unlike our results with QDs and CML, negligible deposition of bare silica NPs occurred at 5 and 10 mM Ca2+ in acid-treated Accusand. The high deposition of QDs and CML particles was therefore attributed to bridging complexation in which Ca2+ serves as a bridge between the cation exchange locations on the clay and carboxyl functional groups on the QD and CML particles, which were absent on the bare silica NPs. Our results suggest that the transport of carboxylic ligand-modified NPs may be limited in subsurface environments because of the ubiquitous presence of clay and divalent cations.

Torkzaban, Saeed; Wan, Jiamin; Tokunaga, Tetsu K.; Bradford, Scott A.

2012-08-01

67

Sand Transport by Wind on Complex Rough Surfaces: Field Studies in the McMurdo Dry Valleys, Antarctica  

Microsoft Academic Search

Although the physics of the movement of sand-sized particles by wind has been extensively studied, significant uncertainties remain in our understanding of the effects of surface roughness on aeolian transport processes. Accounting for the effects of non-erodible, isolated roughness elements on sediment transport by wind is necessary for the development of models that realistically predict rates of transport for complex

N. Lancaster; W. G. Nickling; J. A. Gillies; K. Cupp

2004-01-01

68

Radiological survey and evaluation of the fallout area from the Trinity test: Chupadera Mesa and White Sands Missile Range, New Mexico  

SciTech Connect

Current radiological conditions were evaluated for the site of the first nuclear weapons test, the Trinity test, and the associated fallout zone. The test, located on White Sands Missile Range, was conducted as part of the research with nuclear materials for the World War II Manhattan Engineer District atomic bomb project. Some residual radioactivity attributable to the test was found in the soils of Ground Zero on White Sands Missile Range and the areas that received fallout from the test. The study considered relevant information including historical records, environmental data extending back to the 1940s, and new data acquired by field sampling and measurements. Potential exposures to radiation were evaluated for current land uses. Maximum estimated doses on Chupadera Mesa and other uncontrolled areas are less than 3% of the DOE Radiation Protection Standards (RPSs). Radiation exposures during visits to the US Army-controlled Ground Zero area are less than 1 mrem per annual visit or less than 0.2% of the RPS for a member of the public. Detailed data and interpretations are provided in appendixes. 14 figs., 45 tabs.

Hansen, W.R.; Rodgers, J.C.

1985-06-01

69

XRD and mineralogical analysis of gypsum dunes at White Sands National Monument, New Mexico and applications to gypsum detection on Mars  

NASA Astrophysics Data System (ADS)

A field portable X-ray Diffraction (XRD) instrument was used at White Sands National Monument to perform in-situ measurements followed by laboratory analyses of the gypsum-rich dunes and to determine its modal mineralogy. The field instrument is a Terra XRD (Olympus NDT) based on the technology of the CheMin (Chemistry and Mineralogy) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity which is providing the mineralogical and chemical composition of scooped soil samples and drilled rock powders collected at Gale Crater [1]. Using Terra at White Sands will contribute to 'ground truth' for gypsum-bearing environments on Mars. Together with data provided by VNIR spectra [2], this study clarifies our understanding of the origin and history of gypsum-rich sand dunes discovered near the northern polar region of Mars [3]. The results obtained from the field analyses performed by XRD and VNIR spectroscopy in four dunes at White Sands revealed the presence of quartz and dolomite. Their relative abundance has been estimated using the Reference Intensity Ratio (RIR) method. For this study, particulate samples of pure natural gypsum, quartz and dolomite were used to prepare calibration mixtures of gypsum-quartz and gypsum-dolomite with the 90-150?m size fractions. All single phases and mixtures were analyzed by XRD and RIR factors were calculated. Using this method, the relative abundance of quartz and dolomite has been estimated from the data collected in the field. Quartz appears to be present in low amounts (2-5 wt.%) while dolomite is present at percentages up to 80 wt.%. Samples from four dunes were collected and prepared for subsequent XRD analysis in the lab to estimate their composition and illustrate the changes in mineralogy with respect to location and grain size. Gypsum-dolomite mixtures: The dolomite XRD pattern is dominated by an intense diffraction peak at 2??36 deg. which overlaps a peak of gypsum, This makes low concentrations of dolomite difficult to quantify in mixtures with high concentration of gypsum. Dolomite has been detected in some locations at dune 3 as high as 80 wt.%. Gypsum-quartz mixtures: The intensity of the main diffraction peak of quartz at 2??31 deg. decreases progressively with the decrease of the amount of quartz in the mixtures. Samples from dune 1 and 2 show quartz abundance at 5.6 and 2.6 wt.% respectively . [1] Blake et al. Space Sci. Rev. (2012). doi:10.1007/s11214-012-9905-1. [2] King et al. (2013) AGU, submitted. [3] Langevin et al. (2005). Science 307, 1584-1586.

Lafuente, B.; Bishop, J. L.; Fenton, L. K.; King, S. J.; Blake, D.; Sarrazin, P.; Downs, R.; Horgan, B. H.

2013-12-01

70

LIDAR first results from the Oil Sands Region: A complex vertical atmosphere  

NASA Astrophysics Data System (ADS)

Environment Canada is using LIDAR technology to probe the complex vertical structure of the atmosphere over the oil sands region. This provided the critical vertical context for the interpretation of ground-based chemistry measurements and model verification and validation. In recent years, Environment Canada has designed an autonomous aerosol LIDAR system that can be deployed to remote areas such as the oil sands. The trailer that contains the LIDAR system includes a roof hatch assembly, basic meteorological tower, radar interlock system, climate control system and leveling stabilizers. A precipitation sensor is used to operate the roof hatch and three pan/tilt webcams capture sky conditions and monitor the Lidar system's health. A remote control interface is used to monitor all vital components of the system, including the ability to provide hard resets to the various electronic devices onboard. Every 10 seconds the system provides vertical aerosol profiles from near ground to 20 km. The LIDAR transmitter emits two wavelengths (1064nm and 532nm) and the detector assembly collects three channels (1064nm backscatter, 532nm backscatter and 532nm depolarization). The depolarization channel provided key information in identifying and discriminating the various aerosol layers aloft such as dust, forest fire plumes, industrial plume sources or ice crystals. It operates 24 hours a day, seven days a week except during precipitation events and when aircraft fly over the site. The system is operated remotely and the data are updated every hour to a website to allow near real-time capability. First results from an intensive field campaign will be presented. LIDAR false color plot showing the bottom 7 km of the atmosphere during a forest fire event. Note the forest fire plume is between 1.5 and 5 km.

Strawbridge, K. B.

2012-12-01

71

White-light-emitting Eu(III)-bi-doped macromolecular complexes  

NASA Astrophysics Data System (ADS)

We have synthesized heterometallic complexes based on a copolymer of acrylic acid with butyl methacrylate (BMAC) with a composition [Eu x Bi(1 - x)-BMAC]. These complexes have several emission bands in the visible range. At room temperature, in complexes with a content of Eu(III) of 30-40%, intense white luminescence appears.

Mirochnik, A. G.; Petrochenkova, N. V.; Zhikhareva, P. A.

2014-03-01

72

Efficient white light generation from 2,3-diphenyl-1,2-dihydro-quinoxaline complex  

NASA Astrophysics Data System (ADS)

In this article, we report two organic materials dispersed in transparent poly (methyl methacrylate) matrix for efficient white light simulation under different optical excitations. A newly synthesized complex of benzoin and o-phenyldiamine is observed to be white on illumination with a blue LED. A new concept of white light emitting tube is also demonstrated. A mixture of 2,2?-([1,1'-biphenyl]-4,4'-diyldi-2,1-ethenediyl)-bis-benzenesulfonic acid disodium salt and complex is optimized to emit white light extended in the violet region on 355 nm laser excitation. The optical quality of the emitted white light is adjudged by the CIE coordinate, correlated color temperature and color rendition index in both the cases.

Dwivedi, Y.; Kant, S.; Rai, R. N.; Rai, S. B.

2010-11-01

73

Airborne Measurements of Aerosol Emissions From the Alberta Oil Sands Complex  

NASA Astrophysics Data System (ADS)

The Alberta oil sands contain a vast reservoir of fossil hydrocarbons. The extremely viscous bitumen requires significant energy to extract and upgrade to make a fluid product suitable for pipelines and further refinement. The mining and upgrading process constitute a large industrial complex in an otherwise sparsely populated area of Canada. During the ARCTAS project in June/July 2008, while studying forest fire plumes, the NASA DC-8 and P-3B flew through the plume a total of 5 times. Once was a coordinated visit by both aircraft; the other 3 were fortuitous passes downwind. One study has been published about gas emissions from the complex. Here we concentrate on aerosol emissions and aging. As previously reported, there appear to be at least 2 types of plumes produced. One is an industrial-type plume with vast numbers of ultrafine particles, SO2, sulfate, black carbon (BC), CO, and NO2. The other, probably from the mining, has more organic aerosol and BC together with dust-like aerosols at 3 ?m and a 1 ?m mode of unknown origin. The DC-8 crossed the plume about 10 km downwind of the industrial site, giving time for the boundary layer to mix and enabling a very crude flux calculation suggesting that sulfate and organic aerosols were each produced at about 500 g/s (estimated errors are a factor of 2, chiefly due to concerns about vertical mixing). Since this was a single flight during a project dedicated to other purposes and operating conditions and weather may change fluxes considerably, this may not be a typical flux. As the plume progresses downwind, the ultrafine particles grow to sizes effective as cloud condensation nucei (CCN), SO2 is converted to sulfate, and organic aerosol is produced. During fair weather in the summer, as was the case during these flights, cloud convection pumps aerosol above the mixed layer. While the aerosol plume is difficult to detect from space, NO2 is measured by the OMI instrument an the Aura satellite and the oil sands plume often exceeds the detection limit. There is a rough correlation between NO2 and aerosol, so it may be possible to indirectly monitor aerosol production.

Howell, S. G.; Clarke, A. D.; McNaughton, C. S.; Freitag, S.

2012-12-01

74

Results of calibrations of the NOAA-11 AVHRR made by reference to calibrated SPOT imagery at White Sands, N.M  

NASA Technical Reports Server (NTRS)

The calibration method reported here makes use of the reflectances of several large, uniform areas determined from calibrated and atmospherically corrected SPOT Haute Resolution Visible (HRV) scenes of White Sands, New Mexico. These reflectances were used to predict the radiances in the first two channels of the NOAA-11 Advanced Very High Resolution Radiometer (AVHRR). The digital counts in the AVHRR image corresponding to these known reflectance areas were determined by the use of two image registration techniques. The plots of digital counts versus pixel radiance provided the calibration gains and offsets for the AVHRR. A reduction in the gains of 4 and 13 percent in channels 1 and 2 respectively was found during the period 1988-11-19 to 1990-6-21. An error budget is presented for the method and is extended to the case of cross-calibrating sensors on the same orbital platform in the Earth Observing System (EOS) era.

Nianzeng, Che; Grant, Barbara G.; Flittner, David E.; Slater, Philip N.; Biggar, Stuart F.; Jackson, Ray D.; Moran, M. S.

1991-01-01

75

Application of solid state silicone-29 and carbon-13 nuclear magnetic resonance spectroscopy to the characterization of inorganic matter-humic complexes in Athabasca oil sands  

SciTech Connect

The ease of bitumen recovery from oil sand by hot or cold water separation techniques depends upon the surface properties of the components, especially water wet character of the clay and sand particles. Oil wetting of some of the oils and sand solids is believed to be caused by the presence of humic matter-non-crystalline inorganic complexes. Characterization of these complexes using solid state carbon-13 and silicon-29 magic spinning angle (MAS) NMR spectroscopy was the purpose of the present work.

Kotlyar, L.S.; Ripmeester, J.A.

1988-06-01

76

GBFEL-TIE (Ground-Based Free Electron Laser Technology Experiment) sample survey on White Sands Missile Range, New Mexico: The NASA, Stallion, and Orogrande Alternatives. Final report  

SciTech Connect

Three locations on White Sands Missile Range, New Mexico, are under consideration as alternatives for the proposed Ground-Based Free-Electron Laser Technology Integration Experiment (GBFEL-TIE). The study conducted jointly by Prewitt and Associates, Inc., and the Office of Contract Archeology, was designed to provide input into the GBFEL-TIE Draft Environmental Impact Statement concerning the potential impact of the proposed project on cultural resources in each of the alternatives. The input consists of a series of predictions based on data gathered from two sources: (1) a cultural resource sample survey (15%) of two alternatives conducted as part of this study, and (2) from a previous survey of the third alternative. A predictive model was devleoped and applied using these data that estimated the potential impact of the GBFEL-TIE facility on the cultural resources within each alternative. The predictions indicate that the NASA alternatives, by far, the least favorable location for the facility followed by the Orogrande and Stallion Alternatives.

Seaman, T.J.; Doleman, W.H.

1988-09-30

77

Drilling, construction, and testing of water-supply wells 21 and 22, White Sands Missle Range, Dona Ana County, New Mexico  

USGS Publications Warehouse

During the spring and summer of 1976, two municipal-supply wells (designated as well 21 and well 22 - 2,000 feet apart) were drilled at the Post Headquarters area of White Sands Missile Range, New Mexico. The design specifications for both wells called for 24-inch diameter surface casing cemented in place to a depth of about 430 feet, with 16-inch liner and slotted casing from the surface to a depth of about 700 feet. Each well was pumped continuously for 32 hours in a step-drawdown test. This test consisted of four steps, with discharge rates varying from about 500 to 1,150 gallons per minute. The drawdown test for well 21 gave an estimated transmissivity of 17,300 gallons per day per foot, and a final specific capacity of slightly less than 11 gallons per minute per foot of drawdown. The step-drawdown test and later drawdown and recovery test on well 22 gave an average transmissivity of 32,600 gallons per day per foot, and a final specific capacity of about 15 gallons per minute per foot of drawdown. The data collected indicated that the aquifer in the vicinity of well 22 is more permeable than the aquifer around well 21. Both wells furnish a satisfactory quantity of excellent-quality water. The dissolved-solids content of water from wells 21 and 22 is 232 and 301 mg/liter respectively. (Woodard-USGS)

Wilson, Clyde A.; White, R. R.; Roybal, R. G.; Gonzales, J. L.

1978-01-01

78

22. V2 GANTRY, LAUNCH COMPLEX 33: GENERAL VIEW, LOOKING WEST ...  

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

22. V-2 GANTRY, LAUNCH COMPLEX 33: GENERAL VIEW, LOOKING WEST AND UPWARD FROM APRON OF BLAST PIT, 20,000 POUND MOTOR TEST AND LAUNCH FACILITY - White Sands Missile Range, V-2 Rocket Facilities, Near Headquarters Area, White Sands, Dona Ana County, NM

79

Liquid Oxygen/Liquid Methane Test Summary of the RS-18 Lunar Ascent Engine at Simulated Altitude Conditions at NASA White Sands Test Facility  

NASA Technical Reports Server (NTRS)

Tests were conducted with the RS18 rocket engine using liquid oxygen (LO2) and liquid methane (LCH4) propellants under simulated altitude conditions at NASA Johnson Space Center White Sands Test Facility (WSTF). This project is part of NASA s Propulsion and Cryogenics Advanced Development (PCAD) project. "Green" propellants, such as LO2/LCH4, offer savings in both performance and safety over equivalently sized hypergolic propellant systems in spacecraft applications such as ascent engines or service module engines. Altitude simulation was achieved using the WSTF Large Altitude Simulation System, which provided altitude conditions equivalent up to approx.120,000 ft (approx.37 km). For specific impulse calculations, engine thrust and propellant mass flow rates were measured. Propellant flow rate was measured using a coriolis-style mass-flow meter and compared with a serial turbine-style flow meter. Results showed a significant performance measurement difference during ignition startup. LO2 flow ranged from 5.9-9.5 lbm/sec (2.7-4.3 kg/sec), and LCH4 flow varied from 3.0-4.4 lbm/sec (1.4-2.0 kg/sec) during the RS-18 hot-fire test series. Thrust was measured using three load cells in parallel. Ignition was demonstrated using a gaseous oxygen/methane spark torch igniter. Data was obtained at multiple chamber pressures, and calculations were performed for specific impulse, C* combustion efficiency, and thrust vector alignment. Test objectives for the RS-18 project are 1) conduct a shakedown of the test stand for LO2/methane lunar ascent engines, 2) obtain vacuum ignition data for the torch and pyrotechnic igniters, and 3) obtain nozzle kinetics data to anchor two-dimensional kinetics codes.

Melcher, John C., IV; Allred, Jennifer K.

2009-01-01

80

Infrared Camera Characterization of Bi-Propellant Reaction Control Engines during Auxiliary Propulsion Systems Tests at NASA's White Sands Test Facility in Las Cruces, New Mexico  

NASA Technical Reports Server (NTRS)

This paper describes the application of a FUR Systems A40M infrared (IR) digital camera for thermal monitoring of a Liquid Oxygen (LOX) and Ethanol bi-propellant Reaction Control Engine (RCE) during Auxiliary Propulsion System (APS) testing at the National Aeronautics & Space Administration's (NASA) White Sands Test Facility (WSTF) near Las Cruces, New Mexico. Typically, NASA has relied mostly on the use of ThermoCouples (TC) for this type of thermal monitoring due to the variability of constraints required to accurately map rapidly changing temperatures from ambient to glowing hot chamber material. Obtaining accurate real-time temperatures in the JR spectrum is made even more elusive by the changing emissivity of the chamber material as it begins to glow. The parameters evaluated prior to APS testing included: (1) remote operation of the A40M camera using fiber optic Firewire signal sender and receiver units; (2) operation of the camera inside a Pelco explosion proof enclosure with a germanium window; (3) remote analog signal display for real-time monitoring; (4) remote digital data acquisition of the A40M's sensor information using FUR's ThermaCAM Researcher Pro 2.8 software; and (5) overall reliability of the system. An initial characterization report was prepared after the A40M characterization tests at Marshall Space Flight Center (MSFC) to document controlled heat source comparisons to calibrated TCs. Summary IR digital data recorded from WSTF's APS testing is included within this document along with findings, lessons learned, and recommendations for further usage as a monitoring tool for the development of rocket engines.

Holleman, Elizabeth; Sharp, David; Sheller, Richard; Styron, Jason

2007-01-01

81

Mystery Sand  

NSDL National Science Digital Library

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

Sciencenter

2012-01-01

82

Subduction Complex Provenance redefined: modern sands from the Indo-Burman-Andaman-Nicobar Ridge and Barbados Island  

NASA Astrophysics Data System (ADS)

Subduction complexes large enough to be exposed subaerially and to become significant sources of terrigenous detritus are formed by tectonic accretion above trenches choked with thick sections of remnant-ocean turbidites. They thus need to be connected along strike to a large Alpine-type or Andean-type orogen, where huge volumes of orogenic detritus are produced and conveyed via a major fluvio-deltaic system to the deep sea (Ingersoll et al., 2003). We investigated sediment generation and recycling in the Indo-Burman-Andaman-Nicobar subduction complex, representing the archetype of such settings in the eastern prolongation of the Himalayan collisional system. "Subduction Complex Provenance" is composite, and chiefly consists of detritus recycled from largely turbiditic parent rocks (Recycled Clastic Provenance), with local supply from ultramafic and mafic rocks of forearc lithosphere (Ophiolite Provenance) or recycled paleovolcanic to neovolcanic sources (Volcanic Arc Provenance; Garzanti et al., 2007). In order to specifically investigate the effect of recycling, we characterized the diverse detrital signatures of Cenozoic sandstones deposited during subsequent stages of "soft" and "hard" Himalayan collision and exposed from Bangladesh to the Andaman Islands, and discuss the reasons for compositional discrepancies between parent sandstones and their recycled daughter sands. A companion study was carried out with the same methodologies, rationale and goals on Barbados Island, one of the few other places where a large accretionary prism is subaerially exposed. Also modern Barbados sands are largely multicyclic, reflecting mixing in various proportions of detritus from the basal Scotland Formation (sandstones and mudrocks), their stratigraphic and tectonic cover, the Oceanic Formation (quartzose turbidites and deep-water biogenic oozes including radiolarite), and from the Pleistocene calcarenite and reefal cap, as well as from volcanic layers ultimately derived from the Lesser Antilles. Mixing of detritus recycled from orogen-derived turbidites transported long distance with detritus from oceanic mèlange, pelagic sediments and younger calcareous cap rocks and in addition volcaniclastic products thus redefines the diagnostic mark of Subduction Complex Provenance as quite distinct from the original definition by Dickinson and Suczek (1979). REFERENCES Dickinson, W.R., and Suczek, C.A., 1979, Plate tectonics and sandstone composition: American Association Petroleum Geologists Bulletin, 63, 2164-2172. Garzanti, E., Doglioni, C., Vezzoli, G., and Andò, S., 2007, Orogenic belts and orogenic sediment provenances: Journal of Geology, 115, 315-334. Ingersoll, R.V., Dickinson, W.R., and Graham, S.A., 2003, Remnant-ocean submarine fans: largest sedimentary systems on Earth, [in] Chan, M.A., and Archer, A.W., eds., Extreme Depositional Environments: Mega End Members in Geologic Time: Geological Society of America, Special Paper 370, 191-208.

Limonta, Mara; Resentini, Alberto; Andò, Sergio; Vezzoli, Giovanni; Bandopadhyay, Pinaki C.; Najman, Yani; Boni, Maria; Bechstädt, Thilo; Garzanti, Eduardo

2013-04-01

83

Nuclear and mitochondrial phylogenetic analysis of big-scale sand smelt Atherina boyeri complex in Greece.  

PubMed

Genetic differentiation and phylogenetic relationships of big-scale sand smelt Atherina boyeri specimens from 23 sampling sites in Greece and one from a lake in Turkey were investigated. A total of 2180 base pairs (bp) corresponding to the partial sequence of the mitochondrial gene cytochrome oxidase I (coI), cytochrome b (cytb) and control region, as well as of the nuclear protein-coding gene rhodopsin (rh), were determined for the 143 specimens studied. Phylogenetic analysis of each gene segment separately and of the combined dataset revealed the existence of three different and well divergent lineages in Greece. The first corresponds to the lagoon form, in which a clear distinction between the Aegean and Ionian Sea was observed. The other two correspond to the punctuated and non-punctuated marine forms that have been previously reported. The fact that in the present study a population without black spots on the flanks is clustered with the punctuated form and vice versa, however, suggests that differences in colour pattern do not seem to be a sufficient marker to discriminate the two marine forms. In contrast, the presence of a different length insertion between transfer RNA (tRNA) glutamic acid (tRNA(glu)) and cytb genes in the lagoon and in one of the two forms of marine populations, and its absence from the rest marine-form specimens confirms that this character is conserved and capable to be used for distinguishing the different forms. Even though the divergence values among the different forms were high, their phylogenetic relationships were not able to be resolved. PMID:23020561

Kraitsek, S; Klossa-Kilia, E; Kilias, G

2012-10-01

84

Liquid Oxygen/Liquid Methane Test Results of the RS-18 Lunar Ascent Engine at Simulated Altitude Conditions at NASA White Sands Test Facility  

NASA Technical Reports Server (NTRS)

Tests were conducted with the RS-18 rocket engine using liquid oxygen (LO2) and liquid methane (LCH4) propellants under simulated altitude conditions at NASA Johnson Space Center White Sands Test Facility (WSTF). This project is part of NASA's Propulsion and Cryogenics Advanced Development (PCAD) project. "Green" propellants, such as LO2/LCH4, offer savings in both performance and safety over equivalently sized hypergolic propulsion systems in spacecraft applications such as ascent engines or service module engines. Altitude simulation was achieved using the WSTF Large Altitude Simulation System, which provided altitude conditions equivalent up to 122,000 ft (37 km). For specific impulse calculations, engine thrust and propellant mass flow rates were measured. LO2 flow ranged from 5.9 - 9.5 lbm/sec (2.7 - 4.3 kg/sec), and LCH4 flow varied from 3.0 - 4.4 lbm/sec (1.4 - 2.0 kg/sec) during the RS-18 hot-fire test series. Propellant flow rate was measured using a coriolis mass-flow meter and compared with a serial turbine-style flow meter. Results showed a significant performance measurement difference during ignition startup due to two-phase flow effects. Subsequent cold-flow testing demonstrated that the propellant manifolds must be adequately flushed in order for the coriolis flow meters to give accurate data. The coriolis flow meters were later shown to provide accurate steady-state data, but the turbine flow meter data should be used in transient phases of operation. Thrust was measured using three load cells in parallel, which also provides the capability to calculate thrust vector alignment. Ignition was demonstrated using a gaseous oxygen/methane spark torch igniter. Test objectives for the RS-18 project are 1) conduct a shakedown of the test stand for LO2/methane lunar ascent engines, 2) obtain vacuum ignition data for the torch and pyrotechnic igniters, and 3) obtain nozzle kinetics data to anchor two-dimensional kinetics codes. All of these objectives were met with the RS-18 data and additional testing data from subsequent LO2/methane test programs in 2009 which included the first simulated-altitude pyrotechnic ignition demonstration of LO2/methane.

Melcher, John C., IV; Allred, Jennifer K.

2009-01-01

85

New platinum complexes for hybrid white organic light-emitting diodes  

NASA Astrophysics Data System (ADS)

A new series of mixed ligand platinum(II) complexes with a formula of FPtXND, where XND = 4-hydroxy-1,5-naphthyridine derivates and F = 2-(2,4-difluorophenyl)pyridine, were newly synthesized, and their photophysical properties were examined. Single crystal X-ray diffraction of FPtOPhND were determined to elucidate their variation of solid state phosphorescence and electroluminescence. Organic hole transporting as well as blue light-emitting NPB (1-naphthylphenylbiphenyl diamine) or 4P-NPD (1-naphthylphenylquaterphenyl diamine) was employed in the platinum complex-based hybrid white organic light emitting diodes (WOLEDs) with a simplified device configuration of ITO/4P-NPD or NPB/CBP:FPtXND/TPBI/LiF/Al or ITO/4P-NPD /4P-NPD:FPtXND/TPBI/LiF/Al.

Poloek, Anurach; Chen, Chin-Ti; Chen, Chao-Tsen

2013-09-01

86

Sand Drains.  

National Technical Information Service (NTIS)

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

1994-01-01

87

Effect of organic complexing agents on the interactions of Cs(+), Sr(2+) and UO(2)(2+) with silica and natural sand.  

PubMed

Sorption processes play a key role in controlling radionuclide migration through subsurface environments and can be affected by the presence of anthropogenic organic complexing agents found at contaminated sites. The effect of these complexing agents on radionuclide-solid phase interactions is not well known. Therefore the aim of this study was to examine the processes by which EDTA, NTA and picolinate affect the sorption kinetics and equilibria of Cs(+), Sr(2+) and UO2(2+) onto natural sand. The caesium sorption rate and equilibrium were unaffected by the complexing agents. Strontium however showed greater interaction with EDTA and NTA in the presence of desorbed matrix cations than geochemical modelling predicted, with SrNTA(-) enhancing sorption and SrEDTA(2-) showing lower sorption than Sr(2+). Complexing agents reduced UO2(2+) sorption to silica and enhanced the sorption rate in the natural sand system. Elevated concentrations of picolinate reduced the sorption of Sr(2+) and increased the sorption rate of UO2(2+), demonstrating the potential importance of this complexing agent. These experiments provide a direct comparison of the sorption behaviour of Cs(+), Sr(2+) and UO2(2+)onto natural sand and an assessment of the relative effects of EDTA, NTA and picolinate on the selected elements. PMID:23473428

Reinoso-Maset, Estela; Worsfold, Paul J; Keith-Roach, Miranda J

2013-05-01

88

Discovering Sand and Sand Paintings  

NSDL National Science Digital Library

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

Eichinger, John

2009-05-30

89

Regulation of the brown and white fat gene programs through a PRDM16/CtBP transcriptional complex  

PubMed Central

Brown fat is a specialized tissue that can dissipate energy and counteract obesity through a pattern of gene expression that greatly increases mitochondrial content and uncoupled respiration. PRDM16 is a zinc-finger protein that controls brown fat determination by stimulating brown fat-selective gene expression, while suppressing the expression of genes selective for white fat cells. To determine the mechanisms regulating this switching of gene programs, we purified native PRDM16 protein complexes from fat cells. We show here that the PRDM16 transcriptional holocompex contains C-terminal-binding protein-1 (CtBP-1) and CtBP-2, and this direct interaction selectively mediates the repression of white fat genes. This repression occurs through recruiting a PRDM16/CtBP complex onto the promoters of white fat-specific genes such as resistin, and is abolished in the genetic absence of CtBP-1 and CtBP-2. In turn, recruitment of PPAR-?-coactivator-1? (PGC-1?) and PGC-1? to the PRDM16 complex displaces CtBP, allowing this complex to powerfully activate brown fat genes, such as PGC-1? itself. These data show that the regulated docking of the CtBP proteins on PRDM16 controls the brown and white fat-selective gene programs.

Kajimura, Shingo; Seale, Patrick; Tomaru, Takuya; Erdjument-Bromage, Hediye; Cooper, Marcus P.; Ruas, Jorge L.; Chin, Sherry; Tempst, Paul; Lazar, Mitchell A.; Spiegelman, Bruce M.

2008-01-01

90

Aggregation-induced white-light emission from the triple-stranded dinuclear Sm(iii) complex.  

PubMed

A novel bis-?-diketone ligand, 4,4'-bis(4,4,4-trifluoro-1,3-dioxobutyl)(phenoxy)-1,1'-binaphthalene (BTPB), is designed for synthesis of a white light emissive lanthanide complex. The ligand bears two benzoyl ?-diketonate sites linked by a 1,1'-binaphthoxy spacer. Reaction of the doubly negatively charged bis-bidentate ligand with lanthanide ions forms triple-stranded dinuclear complexes Sm2(BTPB)3(H2O)4 () and Gd2(BTPB)3(H2O)4 (), which have been fully characterized by various spectroscopic techniques. UV-Vis absorption and emission spectroscopic techniques are used to investigate photophysical properties of the ligand and its complexes in THF and CHCl3. In some cases aggregation of the ligand results in the appearance of a new luminescence band at about 510 nm in addition to the monomer fluorescence. In complex , partial energy transfer from BTPB results in Sm(iii)-based red light emission in addition to the BTPB-based blue/green emission. With the variation of the excited wavelength and concentration of the solution, complex shows a tunable white light emission with the balance of three primary colors. This is an unusual case of observation of white light emission from a single molecule Sm(iii) complex. PMID:24841675

Leng, Jiaqi; Li, Hongfeng; Chen, Peng; Sun, Wenbin; Gao, Ting; Yan, Pengfei

2014-07-22

91

WIND VELOCITIES AND SAND FLUXES IN MESQUITE DUNE-LANDS IN THE NORTHERN CHIHUAHUAN DESERT: A COMPARISON BETWEEN FIELD MEASUREMENTS AND THE QUIC (QUICK URBAN AND INDUSTRIAL COMPLEX) MODEL  

EPA Science Inventory

The poster shows comparisons of wind velocities and sand fluxes between field measurements and a computer model, called QUIC (Quick Urban & Industrial Complex). The comparisons were made for a small desert region in New Mexico. ...

92

Tar sands  

Microsoft Academic Search

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

Wennekers; J. H. N

1981-01-01

93

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

94

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

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

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

95

Sands-on Learning.  

ERIC Educational Resources Information Center

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

Vandervoort, Frances S.

1989-01-01

96

Complexity overlooked: enhancing cultural competency in the white lesbian counseling trainee through education and supervision.  

PubMed

Self-awareness is often associated with enhanced multicultural competency. Training programs must work to facilitate self-awareness in counseling trainees who hold both privileged and oppressed identities. In this article, I highlight a gap in the literature regarding how best to supervise white lesbian counseling trainees. Facilitating self-awareness through supervision will be explored as a tool for enhancing multicultural competency in the white lesbian counseling trainee. An exploration of understanding white privilege as well as the impact of oppression on lesbian counseling trainees, will be used to draw conclusions regarding effective supervision for this population. Additionally, suggestions for future research will be proposed. PMID:24641078

Davis, Deanna N

2014-01-01

97

Extracting, Recognizing, and Counting White Blood Cells from Microscopic Images by Using Complex-valued Neural Networks.  

PubMed

In this paper a method related to extracting white blood cells (WBCs) from blood microscopic images and recognizing them and counting each kind of WBCs is presented. In medical science diagnosis by check the number of WBCs and compared with normal number of them is a new challenge and in this context has been discussed it. After reviewing the methods of extracting WBCs from hematology images, because of high applicability of artificial neural networks (ANNs) in classification we decided to use this effective method to classify WBCs, and because of high speed and stable convergence of complex-valued neural networks (CVNNs) compare to the real one, we used them to classification purpose. In the method that will be introduced, first the white blood cells are extracted by RGB color system's help. In continuance, by using the features of each kind of globules and their color scheme, a normalized feature vector is extracted, and for classifying, it is sent to a complex-valued back-propagation neural network. And at last, the results are sent to the output in the shape of the quantity of each of white blood cells. Despite the low quality of the used images, our method has high accuracy in extracting and recognizing WBCs by CVNNs, and because of this, certainly its result on high quality images will be acceptable. Learning time of complex-valued neural networks, that are used here, was significantly less than real-valued neural networks. PMID:23717809

Akramifard, Hamid; Firouzmand, Mohammad; Moghadam, Reza Askari

2012-07-01

98

Characteristics of White Organic Light-Emitting Diodes Using Heteroleptic Iridium Complexes for Green and Red Phosphorescence  

Microsoft Academic Search

We have demonstrated red-green-blue emissive white organic light-emitting diodes (RGB-WOLEDs) by using two emissive materials as dopant, 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi) and heteroleptic tris-cyclometalated iridium(III) complexes. It was found that the heteroleptic iridium complexes, bis(2-phenylquinoline)(2-p-tolylpyridine) iridium(III) [Ir(pq)2(tpy)] and bis(2-p-tolylpyridine)(2-phenylquinoline) iridium(III) [Ir(tpy)2(pq)], used in this study showed double emissive colors, where the pq and tpy ligands emitted red and green colors, respectively. The

Ji Hyun Seo; In Jun Kim; Young Kwan Kim; Young Sik Kim

2008-01-01

99

Gas percolation through sand  

NASA Astrophysics Data System (ADS)

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

Proud, W. G.

2014-05-01

100

Efficient and tunable white-light emission of metal-organic frameworks by iridium-complex encapsulation.  

PubMed

Metal-organic frameworks (MOFs) are well known for their tunable structure and porosity. Many studies have shown they are promising for various important applications, for which their performance can be further enhanced by encapsulating functional species, such as luminescent guest molecules, within the frameworks. Although numerous MOFs are luminescent, very few emit white light and their quantum yield is usually low. Here we report a strategy to achieve efficient white-light emission by encapsulating an iridium complex in the MOF cavity. A mesoporous blue-emitting MOF is prepared as host to encapsulate a yellow-emitting iridium complex, [Ir(ppy)2(bpy)](+). The resultant composites emit bright white light with good colour quality (for example, Commission International de I'Eclairage coordinates, colour-rendering index and correlated colour temperature of (0.31, 0.33), 84.5 and 5409?K, respectively), and high quantum yield up to 115?°C. This strategy may open new perspectives for developing high-performance energy-saving solid-state lighting materials. PMID:24212250

Sun, Chun-Yi; Wang, Xin-Long; Zhang, Xiao; Qin, Chao; Li, Peng; Su, Zhong-Min; Zhu, Dong-Xia; Shan, Guo-Gang; Shao, Kui-Zhan; Wu, Han; Li, Jing

2013-11-11

101

Efficient and tunable white-light emission of metal-organic frameworks by iridium-complex encapsulation  

PubMed Central

Metal–organic frameworks (MOFs) are well known for their tunable structure and porosity. Many studies have shown they are promising for various important applications, for which their performance can be further enhanced by encapsulating functional species, such as luminescent guest molecules, within the frameworks. Although numerous MOFs are luminescent, very few emit white light and their quantum yield is usually low. Here we report a strategy to achieve efficient white-light emission by encapsulating an iridium complex in the MOF cavity. A mesoporous blue-emitting MOF is prepared as host to encapsulate a yellow-emitting iridium complex, [Ir(ppy)2(bpy)]+. The resultant composites emit bright white light with good colour quality (for example, Commission International de I’Eclairage coordinates, colour-rendering index and correlated colour temperature of (0.31, 0.33), 84.5 and 5409?K, respectively), and high quantum yield up to 115?°C. This strategy may open new perspectives for developing high-performance energy-saving solid-state lighting materials.

Sun, Chun-Yi; Wang, Xin-Long; Zhang, Xiao; Qin, Chao; Li, Peng; Su, Zhong-Min; Zhu, Dong-Xia; Shan, Guo-Gang; Shao, Kui-Zhan; Wu, Han; Li, Jing

2013-01-01

102

Tar sands  

SciTech Connect

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

Wennekers, J.H.N.

1981-10-01

103

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

104

Sand Babies  

NSDL National Science Digital Library

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

Pbs

2012-01-01

105

"It's Almost like a White School Now": Racialised Complexities, Indigenous Representation and School Leadership  

ERIC Educational Resources Information Center

Drawing on a broader study that focused on examining principal leadership for equity and diversity, this paper presents the leadership experiences of "Jane", a White, middle-class principal of a rural Indigenous school. The paper highlights how Jane's leadership is inextricably shaped by her assumptions about race and the political dynamics and…

Keddie, Amanda; Niesche, Richard

2012-01-01

106

Sand ridges off Sarasota, Florida: A complex facies boundary on a low-energy inner shelf environment  

USGS Publications Warehouse

The innermost shelf off Sarasota, Florida was mapped using sidescan-sonar imagery, seismic-reflection profiles, surface sediment samples, and short cores to define the transition between an onshore siliciclastic sand province and an offshore carbonate province and to identify the processes controlling the distribution of these distinctive facies. The transition between these facies is abrupt and closely tied to the morphology of the inner shelf. A series of low-relief nearly shore-normal ridges characterize the inner shelf. Stratigraphically, the ridges are separated from the underlying Pleistocene and Tertiary carbonate strata by the Holocene ravinement surface. While surficial sediment is fine to very-fine siliciclastic sand on the southeastern sides of the ridges and shell hash covers their northwestern sides, the cores of these Holocene deposits are a mixture of both of these facies. Along the southeastern edges of the ridges the facies boundary coincides with the discontinuity that separates the ridge deposits from the underlying strata. The transition from siliciclastic to carbonate sediment on the northwestern sides of the ridges is equally abrupt, but it falls along the crests of the ridges rather than at their edges. Here the facies transition lies within the Holocene deposit, and appears to be the result of sediment reworking by modern processes. This facies distribution primarily appears to result from south-flowing currents generated during winter storms that winnow the fine siliciclastic sediment from the troughs and steeper northwestern sides of the ridges. A coarse shell lag is left armoring the steeper northwestern sides of the ridges, and the fine sediment is deposited on the gentler southeastern sides of the ridges. This pronounced partitioning of the surficial sediment appears to be the result of the siliciclastic sand being winnowed and transported by these currents while the carbonate shell hash falls below the threshold of sediment movement and is left as a lag. The resulting facies boundaries on this low-energy, sediment-starved inner continental shelf are of two origins which both are tied to the remarkably subtle ridge morphology. Along the southeastern sides of the ridges the facies boundary coincides with a stratigraphic discontinuity that separates Holocene from the older deposits while the transition along the northwestern sides of the ridges is within the Holocene deposit and is the result of sediment redistribution by modern processes. ?? 2003 Elsevier B.V. All rights reserved.

Twichell, D.; Brooks, G.; Gelfenbaum, G.; Paskevich, V.; Donahue, B.

2003-01-01

107

White Rock  

NASA Technical Reports Server (NTRS)

14 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the famous 'White Rock' feature in Pollack Crater in the Sinus Sabaeus region of Mars. The light-toned rock is not really white, but its light tone caught the eye of Mars geologists as far back as 1972, when it was first spotted in images acquired by Mariner 9. The light-toned materials are probably the remains of a suite of layered sediments that once spread completely across the interior of Pollack Crater. Dark materials in this image include sand dunes and large ripples.

Location near: 8.1oS, 335.1oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Summer

2005-01-01

108

Beach Sand  

NSDL National Science Digital Library

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

Eberle, Francis; Farrin, Lynn; Keeley, Page

2005-01-01

109

White Rock  

NASA Technical Reports Server (NTRS)

(Released 19 April 2002) The Science 'White Rock' is the unofficial name for this unusual landform which was first observed during the Mariner 9 mission in the early 1970's. As later analysis of additional data sets would show, White Rock is neither white nor dense rock. Its apparent brightness arises from the fact that the material surrounding it is so dark. Images from the Mars Global Surveyor MOC camera revealed dark sand dunes surrounding White Rock and on the floor of the troughs within it. Some of these dunes are just apparent in the THEMIS image. Although there was speculation that the material composing White Rock could be salts from an ancient dry lakebed, spectral data from the MGS TES instrument did not support this claim. Instead, the White Rock deposit may be the erosional remnant of a previously more continuous occurrence of air fall sediments, either volcanic ash or windblown dust. The THEMIS image offers new evidence for the idea that the original deposit covered a larger area. Approximately 10 kilometers to the southeast of the main deposit are some tiny knobs of similarly bright material preserved on the floor of a small crater. Given that the eolian erosion of the main White Rock deposit has produced isolated knobs at its edges, it is reasonable to suspect that the more distant outliers are the remnants of a once continuous deposit that stretched at least to this location. The fact that so little remains of the larger deposit suggests that the material is very easily eroded and simply blows away. The Story Fingers of hard, white rock seem to jut out like icy daggers across a moody Martian surface, but appearances can be deceiving. These bright, jagged features are neither white, nor icy, nor even hard and rocky! So what are they, and why are they so different from the surrounding terrain? Scientists know that you can't always trust what your eyes see alone. You have to use other kinds of science instruments to measure things that our eyes can't see . . . things like information about what kinds of minerals make up the landforms. Mars scientists once thought, for instance, that these unusual features might be vast hills of salt, the dried up remains of a long-ago, evaporated lake. Not so, said an instrument on the Mars Global Surveyor spacecraft, which revealed that the bright material is probably made up of volcanic ash or windblown dust instead. And talk about a cyclical 'ashes to ashes, dust to dust' story! Particles of this material fell and fell until they built up quite a sedimentary deposit, which was then only eroded away again by the wind over time, leaving the spiky terrain seen today. It looks white, but its apparent brightness arises from the fact that the surrounding material is so dark. Of course, good eyesight always helps in understanding. A camera on Mars Global Surveyor with close-up capabilities revealed that sand dunes are responsible for the smudgy dark material in the bright sediment and around it. But that's not all. The THEMIS camera on the Mars Odyssey spacecraft that took this image reveals that this ashy or dusty deposit once covered a much larger area than it does today. Look yourself for two small dots of white material on the floor of a small crater nearby (center right in this image). They preserve a record that this bright deposit once reached much farther. Since so little of it remains, you can figure that the material probably isn't very hard, and simply blows away. One thing's for sure. No one looking at this image could ever think that Mars is a boring place. With all of its bright and dark contrasts, this picture would be perfect for anyone who loves Ansel Adams and his black-and-white photography.

2002-01-01

110

Solid-State Light-Emitting Electrochemical Cells Based on Cationic Transition Metal Complexes for White Light Generation  

Microsoft Academic Search

\\u000a Solid-state light-emitting electrochemical cells (LECs) based on cationic transition metal complexes (CTMCs) exhibit several\\u000a advantages over conventional light-emitting diodes such as simple fabrication processes, low-voltage operation, and high power\\u000a efficiency. Hence, white CTMC-based LECs may be competitive for lighting applications. In this chapter, we review previous\\u000a important works on CTMC-based LECs, such as increasing device efficiency, color tuning, lengthening device

Hai-Ching Su; Ken-Tsung Wong; Chung-Chih Wu

2010-01-01

111

Functionalization of white phosphorus in the coordination sphere of transition metal complexes  

Microsoft Academic Search

This review highlights the stoichiometric functionalization of both white phosphorus and naked Pn fragments derived from the metal-mediated demolition of the P4 tetrahedron. In a first section, the alkylation of Pn ligands is discussed giving specific examples such as: (i) the electrophilic alkylation of ?3-P3 or, ?,?3-P3 ligands: (ii) the transfer of a methyl group from molybdenum to ?5-P5 ligands

Maurizio Peruzzini; Rumia R. Abdreimova; Yulia Budnikova; Antonio Romerosa; Otto J. Scherer; Helmut Sitzmann

2004-01-01

112

Theoretical and functional complexity of white variegation of unripe fleshy fruits  

PubMed Central

In many plant species, the bright colors of ripe fruit serve to attract frugivores to enable efficient seed dispersal. Here I show that the fleshy fruit of several dozens of species originating from Asia (southeastern, eastern and central), the Middle East, Africa, America (South, Central and North), Australia, Polynesia and Micronesia, with fruit usually larger than 1 cm, have white or light green spots while they are still unripe. In many of these species, while the spots are conspicuous, the unripe fruit is known to be poisonous, bitter or sour. I propose that this fruit syndrome may signal frugivores that the fruit is still unripe. Similarly to the succulent leaves of window-plants, these spots form windows that enable light to penetrate deeper into the photosynthetic layers in the developing fruit. This seems to be a solution to overcome the limitations of light harvest because of the high volume to surface ratio of developing fleshy fruits. The white or whitish variegation in these unripe fleshy fruits may serve at least five functions: 1) Windows for photosynthesis, 2) camouflage, 3) signaling to frugivores that they are not ripe (possibly sometimes a type of mutualism with frugivores), 4) signaling to frugivores that they are poisonous - aposematism, and 5) mimicking insect eggs to reduce egg laying. All these functions may be partly or fully simultaneous. Because these white spots appear in plants of diverse geographical and taxonomic origin, it is probably an old adaptation, and such a syndrome has appeared and been selected for many times.

Lev-Yadun, Simcha

2013-01-01

113

Tar sands development  

Microsoft Academic Search

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

1973-01-01

114

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

115

Assessing the Martian surface distribution of aeolian sand using a Mars general circulation model  

Microsoft Academic Search

A sand transport model using White's [1979] sand flux equation and the Mars general circulation model [Pollack et al., 1990] was developed to understand the erosional sources, transport pathways, and depositional sinks of windblown sand on Mars. An initially uniform distribution of sand (4 mm over the entire surface) is regionally transported based on wind stress, saltation threshold, and percentage

F. S. Anderson; R. Greeley; P. Xu; E. Lo; D. G. Blumberg; R. M. Haberle; J. R. Murphy

1999-01-01

116

Large-eddy Simulation of Boundary Layer Flow over Desert Sand Dune Structures  

NASA Astrophysics Data System (ADS)

Complex spatiotemporal coupling exists between desert sand dune topography and surface layer physics of the atmospheric boundary layer (ABL). Although the interactions of individual desert sand dunes have been extensively studied, with categorical interaction mechanisms identified, the aero-mechanical coupling associated with these dune interactions remains an open problem. Large-eddy simulation (LES) is used to simulate turbulent boundary layer flow over dune structures from White Sands, NM. The dunes are resolved with an immersed boundary method (IBM). The flow-forcing (imposed pressure gradient) is varied to simulate the three common prevailing wind conditions at White Sands (southwest, southeast, and northwest, with southwest being the most common). In the present research, comparison between flow statistics (dune wall pressure distribution retrieved from the IBM) and time-difference dune elevation data are used to characterize the mechanisms responsible for erosion (stoss side) and deposition (lee side) of sand. Additionally, statistical details of time series of aerodynamic forcing at different locations on the dune face are evaluated, which may be used to deepen understanding of erosion and deposition events observed in the time-difference lidar data.

Uhlrich, S.; Anderson, W.; Passalacqua, P.; Mohrig, D. C.; Kocurek, G.

2012-12-01

117

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

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

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

118

White organic light-emitting devices employing phosphorescent iridium complex as RGB dopants  

Microsoft Academic Search

Efficient phosphorescent white organic light-emitting diodes (WOLEDs) were realized by using a bright blue-emitting layer, iridium (III) bis-[(4,6- di-fluoropheny)-pyridinato-N, C2'] picolinate doped 4.4'-bis-(9-carbazolyl)-2, 2'-dimethyl-biphenyl doped, together with tris-(2-phenylpyridine) iridium and bis-(1-phenyl-isoquinoline) acetylacetonate iridium (III) are codoped into a 4,4'-N,N'-dicarbazole- biphenyl layer to provide blue, green and red emission for colour mixing. The device emission colour is controlled by varying dopant

Ruili Song; Yu Duan; Shufen Chen; Yi Zhao; Jingying Hou; Shiyong Liu

2007-01-01

119

Ganges Chasma Sands  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

120

Spatial HARDI: improved visualization of complex white matter architecture with Bayesian spatial regularization.  

PubMed

Imaging of water diffusion using magnetic resonance imaging has become an important noninvasive method for probing the white matter connectivity of the human brain for scientific and clinical studies. Current methods, such as diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI) such as q-ball imaging, and diffusion spectrum imaging (DSI), are limited by low spatial resolution, long scan times, and low signal-to-noise ratio (SNR). These methods fundamentally perform reconstruction on a voxel-by-voxel level, effectively discarding the natural coherence of the data at different points in space. This paper attempts to overcome these tradeoffs by using spatial information to constrain the reconstruction from raw diffusion MRI data, and thereby improve angular resolution and noise tolerance. Spatial constraints are specified in terms of a prior probability distribution, which is then incorporated in a Bayesian reconstruction formulation. By taking the log of the resulting posterior distribution, optimal Bayesian reconstruction is reduced to a cost minimization problem. The minimization is solved using a new iterative algorithm based on successive least squares quadratic descent. Simulation studies and in vivo results are presented which indicate significant gains in terms of higher angular resolution of diffusion orientation distribution functions, better separation of crossing fibers, and improved reconstruction SNR over the same HARDI method, spherical harmonic q-ball imaging, without spatial regularization. Preliminary data also indicate that the proposed method might be better at maintaining accurate ODFs for smaller numbers of diffusion-weighted acquisition directions (hence faster scans) compared to conventional methods. Possible impacts of this work include improved evaluation of white matter microstructural integrity in regions of crossing fibers and higher spatial and angular resolution for more accurate tractography. PMID:20670684

Raj, Ashish; Hess, Christopher; Mukherjee, Pratik

2011-01-01

121

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

122

Effect of adsorbed metals ions on the transport of Zn- and Ni-EDTA complexes in a sand and gravel aquifer  

USGS Publications Warehouse

Adsorption, complexation, and dissolution reactions strongly influenced the transport of metal ions complexed with ethylenediaminetetraacetic acid (EDTA) in a predominantly quartz-sand aquifer during two tracer tests conducted under mildly reducing conditions at pH 5.8 to 6.1. In tracer test M89, EDTA complexes of zinc (Zn) and nickel (Ni), along with excess free EDTA, were injected such that the lower portion of the tracer cloud traveled through a region with adsorbed manganese (Mn) and the upper portion of the tracer cloud traveled through a region with adsorbed Zn. In tracer test S89, Ni- and Zn-EDTA complexes, along with excess EDTA complexed with calcium (Ca), were injected into a region with adsorbed Mn. The only discernable chemical reaction between Ni-EDTA and the sediments was a small degree of reversible adsorption leading to minor retardation. In the absence of adsorbed Zn, the injected Zn was displaced from EDTA complexes by iron(III) [Fe(III)] dissolved from the sediments. Displacement of Zn by Fe(III) on EDTA became increasingly thermodynamically favorable with decreasing total EDTA concentration. The reaction was slow compared to the time-scale of transport. Free EDTA rapidly dissolved aluminum (Al) from the sediments, which was subsequently displaced slowly by Fe. In the portion of tracer cloud M89 that traveled through the region contaminated with adsorbed Zn, little displacement of Zn complexed with EDTA was observed, and Al was rapidly displaced from EDTA by Zn desorbed from the sediments, in agreement with equilibrium calculations. In tracer test S89, desorption of Mn dominated over the more thermodynamically favorable dissolution of Al oxyhydroxides. Comparison with results from M89 suggests that dissolution of Al oxyhydroxides in coatings on these sediment grains by Ca-EDTA was rate-limited whereas that by free EDTA reached equilibrium on the time-scale of transport. Rates of desorption are much faster than rates of dissolution of Fe oxyhydroxides from sediment-grain surfaces and, therefore, adsorbed metal ions can strongly influence the speciation of ligands like EDTA in soils and sediments, especially over small temporal and spatial scales. Copyright ?? 2002 Elsevier Science Ltd.

Kent, D. B.; Davis, J. A.; Anderson, L. C. D.; Rea, B. A.; Coston, J. A.

2002-01-01

123

Sand Dunes in Noachis Terra  

NASA Technical Reports Server (NTRS)

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

2004-01-01

124

Sand Diver  

NASA Astrophysics Data System (ADS)

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

Scott, Alan J.

2005-01-01

125

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

126

Sexual dimorphism in white campion: complex control of carpel number is revealed by y chromosome deletions.  

PubMed Central

Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is under the control of two main regions on the Y chromosome. One such region, encoding the gynoecium-suppressing function (GSF), is responsible for the arrest of carpel initiation in male flowers. To generate chromosomal deletions, we used pollen irradiation in male plants to produce hermaphroditic mutants (bsx mutants) in which carpel development was restored. The mutants resulted from alterations in at least two GSF chromosomal regions, one autosomal and one located on the distal half of the (p)-arm of the Y chromosome. The two mutations affected carpel development independently, each mutation showing incomplete penetrance and variegation, albeit at significantly different levels. During successive meiotic generations, a progressive increase in penetrance and a reduction in variegation levels were observed and quantified at the level of the Y-linked GSF (GSF-Y). Possible mechanisms are proposed to explain the behavior of the bsx mutations: epigenetic regulation or/and second-site mutation of modifier genes. In addition, studies on the inheritance of the hermaphroditic trait showed that, unlike wild-type Y chromosomes, deleted Y chromosomes can be transmitted through both the male and the female lines. Altogether, these findings bring experimental support, on the one hand, to the existence on the Y chromosome of genic meiotic drive function(s) and, on the other hand, to models that consider that dioecy evolved through multiple mutation events. As such, the GSF is actually a system containing more than one locus and whose primary component is located on the Y chromosome.

Lardon, A; Georgiev, S; Aghmir, A; Le Merrer, G; Negrutiu, I

1999-01-01

127

Measurements of thermal updraft intensity over complex terrain using American white pelicans and a simple boundary-layer forecast model  

USGS Publications Warehouse

An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of soaring American white pelicans and from diagnostic boundary-layer model-produced estimates of the boundary-layer depth zi and the convective velocity scale w*. Comparison of the flatland data with the profiles of normalized updraft velocity obtained from previous studies reveals that the pelican-derived measurements of thermal updraft intensity are in close agreement with those obtained using traditional research aircraft and large eddy simulation (LES) in the height range of 0.2 to 0.8 zi. Given the success of this method, the profiles of thermal vertical velocity over the flatland and the nearby mountains are compared. This comparison shows that these profiles are statistically indistinguishable over this height range, indicating that the profile for thermal updraft intensity varies little over this sample of complex terrain. These observations support the findings of a recent LES study that explored the turbulent structure of the boundary layer using a range of terrain specifications. For terrain similar in scale to that encountered in this study, results of the LES suggest that the terrain caused less than an 11% variation in the standard deviation of vertical velocity.

Shannon, H. D.; Young, G. S.; Yates, M.; Fuller, Mark R.; Seegar, W.

2003-01-01

128

Measurements Of Thermal Updraft Intensity Over Complex Terrain Using American White Pelicans And A Simple Boundary-Layer Forecast Model  

NASA Astrophysics Data System (ADS)

An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of soaring American white pelicans and from diagnostic boundary-layer model-produced estimates of the boundary-layer depth zi and the convective velocity scale w*. Comparison of the flatland data with the profiles of normalized updraft velocity obtained from previous studies reveals that the pelican-derived measurements of thermal updraft intensity are in close agreement with those obtained using traditional research aircraft and large eddy simulation (LES) in the height range of 0.2 to 0.8 zi. Given the success of this method, the profiles of thermal vertical velocity over the flatland and the nearby mountains are compared. This comparison shows that these profiles are statistically indistinguishable over this height range, indicating that the profile for thermal updraft intensity varies little over this sample of complex terrain. These observations support the findings of a recent LES study that explored the turbulent structure of the boundary layer using a range of terrain specifications. For terrain similar in scale to that encountered in this study, results of the LES suggest that the terrain caused less than an 11% variation in the standard deviation of vertical velocity.

Shannon, Harlan D.; Young, George S.; Yates, Michael A.; et al.

129

Measurements of thermal intensity over complex terrain using American white pelicans and a simple boundary layer forecast model  

NASA Astrophysics Data System (ADS)

An examination of boundary layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of soaring American White Pelicans and from diagnostic boundary layer model-produced estimates of the boundary layer depth zi and the convective velocity scale w*. Comparison of the flatland data with the profiles of normalized updraft velocity obtained from previous studies reveals that the pelican-derived measurements of thermal intensity are in close agreement with those obtained using traditional research aircraft and large eddy simulation (LES) in the height range of 0.2 to 0.8 zi. Given the success of this method, the profiles of thermal vertical velocity over the flatland and the nearby mountains are compared. This comparison shows that these profiles are statistically indistinguishable over this height range, indicating that the profile for thermal intensity varies little over this sample of complex terrain. These observations support the findings of a recent LES study that explored the turbulent structure of the boundary layer using a range of terrain specifications. For terrain similar in scale to that encountered in this study, results of this LES suggest that this terrain caused less than an 11% variation in the standard deviation of vertical velocity.

Shannon, Harlan Donald

2001-11-01

130

Increased white matter connectivity in euthymic bipolar patients: diffusion tensor tractography between the subgenual cingulate and the amygdalo-hippocampal complex  

Microsoft Academic Search

Bipolar disorder has been associated with anatomical as well as functional abnormalities in a brain network that mediates normal and impaired emotion regulation. Previous brain imaging studies have highlighted the subgenual cingulate (SC) and the amygdalo-hippocampal (AH) complex as core regions of this network. Thus we investigated white matter (WM) fiber tracts between the SC and the AH region, the

J Houenou; M Wessa; G Douaud; M Leboyer; S Chanraud; M Perrin; C Poupon; J-L Martinot; M-L Paillere-Martinot

2007-01-01

131

Complex Geometric Models of Diffusion and Relaxation in Healthy and Damaged White Matter  

PubMed Central

Which aspects of tissue microstructure affect diffusion weighted MRI signals? Prior models, many of which use Monte-Carlo simulations, have focused on relatively simple models of the cellular microenvironment and have not considered important anatomic details. With the advent of higher-order analysis models for diffusion imaging, such as high-angular-resolution diffusion imaging (HARDI), more realistic models are necessary. This paper presents and evaluates the reproducibility of simulations of diffusion in complex geometries. Our framework is quantitative, does not require specialized hardware, is easily implemented with little programming experience, and is freely available as open-source software. Models may include compartments with different diffusivities, permeabilities, and T2 time constants using both parametric (e.g., spheres and cylinders) and arbitrary (e.g., mesh-based) geometries. Three-dimensional diffusion displacement-probability functions are mapped with high reproducibility, and thus can be readily used to assess reproducibility of diffusion-derived contrasts.

Farrell, Jonathan A.D.; Smith, Seth A.; Reich, Daniel S.; Calabresi, Peter A.; van Zijl, Peter C.M.

2010-01-01

132

A newly identified protein complex that mediates white spot syndrome virus infection via chitin-binding protein.  

PubMed

White spot syndrome virus (WSSV) is a large enveloped virus which has caused severe mortality and huge economic losses in the shrimp farming industry. The enveloped virus must be combined with the receptors of the host cell membrane by the virus envelope proteins. In the case of WSSV, binding of envelope proteins with receptors of the host cell membrane was discovered in a number of previous studies, such as VP53A and 10 other proteins with chitin-binding protein (CBP), VP28 with Penaeus monodon Rab7, VP187 with ?-integrin, and so on. WSSV envelope proteins were also considered capable of forming a protein complex dubbed an 'infectome'. In this study, the research was focused on the role of CBP in the WSSV infection process, and the relationship between CBP and the envelope proteins VP24, VP28, VP31, VP32 VP39B, VP53A and VP56. The results of the reverse transcription-PCR analyses showed that CBP existed in a variety of shrimp. The speed of WSSV infection could be slowed down by inhibiting CBP gene expression. Far-Western blot analysis and His pull-down assays were conducted, and a protein complex was found that appeared to be composed of a 'linker' protein consisting of VP31, VP32 and VP39B together with four envelope proteins, including VP24, VP28, VP53A and VP56. This protein complex was possibly another part of the infectome and the possible binding region with CBP. The findings of this study may have identified certain points for further WSSV research. PMID:24836670

Huang, Po-Yu; Leu, Jiann-Horng; Chen, Li-Li

2014-08-01

133

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

134

Luminescence color-tuning through polymorph doping: preparation of a white-emitting solid from a single gold(I)-isocyanide complex by simple precipitation.  

PubMed

We report the luminescent color tuning of a new complex, 2-benzothiophenyl(4-methoxyphenyl isocyanide)gold(I) (1), by using a new "polymorph doping" approach. The slow crystallization of the complex 1 afforded three different pure polymorphic crystals with blue, green, and orange emission under UV-light irradiation. The crystal structures of pure polymorphs of 1 were investigated in detail by means of single-crystal X-ray analyses. Theoretical calculations based on the single-crystal structures provided qualitative explanation of the difference in the excited energy-levels of the three polymorphs of 1. In sharp contrast, the rapid precipitation of 1, with the optimized conditions reproducibly afforded homogeneous powder materials showing solid-state white-emission with Commission Internationale de l'Éclairage (CIE) 1931 chromaticity coordinates of (0.33, 0.35), which is similar to pure white. New "polymorphic doping" has been revealed to be critical to this white emission through spectroscopic and X-ray diffraction analyses. The coexistence of the multiple polymorphs of 1 within the homogeneous powder materials and the ideal mixing of multiple luminescent colors gave its white emission accompanied with energy transfer from the predominant green-emitting polymorph to the minor orange-emitting polymorph. PMID:24249690

Seki, Tomohiro; Kurenuma, Sayaka; Ito, Hajime

2013-11-25

135

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

136

Sand Analysis Lab Activity  

NSDL National Science Digital Library

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

Weiss, Tarin

137

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.

138

Asbestos in play sand  

Microsoft Academic Search

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

A. M. Langer; R. P. Nolan

1987-01-01

139

Exploring Products: Nano Sand  

NSDL National Science Digital Library

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

Network, Nanoscale I.; Sciencenter

2010-01-01

140

Qualifying tight sands  

Microsoft Academic Search

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

Harbert

1981-01-01

141

Books of sand  

Microsoft Academic Search

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

Sardón Mariano

2006-01-01

142

High-efficiency tris(8-hydroxyquinoline)aluminum (Alq3) complexes for organic white-light-emitting diodes and solid-state lighting.  

PubMed

Combinations of electron-withdrawing and -donating substituents on the 8-hydroxyquinoline ligand of the tris(8-hydroxyquinoline)aluminum (Alq(3)) complexes allow for control of the HOMO and LUMO energies and the HOMO-LUMO gap responsible for emission from the complexes. Here, we present a systematic study on tuning the emission and electroluminescence (EL) from Alq(3) complexes from the green to blue region. In this study, we explored the combination of electron-donating substituents on C4 and C6. Compounds 1-6 displayed the emission tuning between 478 and 526 nm, and fluorescence quantum yield between 0.15 and 0.57. The compounds 2-6 were used as emitters and hosts in organic light-emitting diodes (OLEDs). The highest OLED external quantum efficiency (EQE) observed was 4.6%, which is among the highest observed for Alq(3) complexes. Also, the compounds 3-5 were used as hosts for red phosphorescent dopants to obtain white light-emitting diodes (WOLED). The WOLEDs displayed high efficiency (EQE up to 19%) and high white color purity (color rendering index (CRI?85). PMID:21780202

Pérez-Bolívar, César; Takizawa, Shin-ya; Nishimura, Go; Montes, Victor A; Anzenbacher, Pavel

2011-08-01

143

Shock and release behaviour of sand  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

144

VIVID interacts with the WHITE COLLAR complex and FREQUENCY-interacting RNA helicase to alter light and clock responses in Neurospora  

PubMed Central

The photoreceptor and PAS/LOV protein VIVID (VVD) modulates blue-light signaling and influences light and temperature responses of the circadian clock in Neurospora crassa. One of the main actions of VVD on the circadian clock is to influence circadian clock phase by regulating levels of the transcripts encoded by the central clock gene frequency (frq). How this regulation is achieved is unknown. Here we show that VVD interacts with complexes central for circadian clock and blue-light signaling, namely the WHITE-COLLAR complex (WCC) and FREQUENCY-interacting RNA helicase (FRH), a component that complexes with FRQ to mediate negative feedback control in Neurospora. VVD interacts with FRH in the absence of WCC and FRQ but does not seem to control the exosome-mediated negative feedback loop. Instead, VVD acts to modulate the transcriptional activity of the WCC.

Hunt, Suzanne M.; Thompson, Seona; Elvin, Mark; Heintzen, Christian

2010-01-01

145

Kentucky tar sand project  

Microsoft Academic Search

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

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

1985-01-01

146

Sand Sea Wonders: Geology  

NSDL National Science Digital Library

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

147

Zeeman tomography of magnetic white dwarfs. IV. The complex field structure of the polars EF Eridani, BL Hydri and CP Tucanae  

NASA Astrophysics Data System (ADS)

Context: The magnetic fields of the accreting white dwarfs in magnetic cataclysmic variables (mCVs) determine the accretion geometries, the emission properties, and the secular evolution of these objects. Aims: We determine the structure of the surface magnetic fields of the white dwarf primaries in magnetic CVs using Zeeman tomography. Methods: Our study is based on orbital-phase resolved optical flux and circular polarization spectra of the polars EF Eri, BL Hyi, and CP Tuc obtained with FORS1 at the ESO VLT. An evolutionary algorithm is used to synthesize best fits to these spectra from an extensive database of pre-computed Zeeman spectra. The general approach has been described in previous papers of this series. Results: The results achieved with simple geometries as centered or offset dipoles are not satisfactory. Significantly improved fits are obtained for multipole expansions that are truncated at degree l_max=3 or 5 and include all tesseral and sectoral components with 0? m? l. The most frequent field strengths of 13, 18, and 10 MG for EF Eri, BL Hyi, and CP Tuc, and the ranges of field strength covered are similar for the dipole and multipole models, but only the latter provide access to accreting matter at the right locations on the white dwarf. The results suggest that the field geometries of the white dwarfs in short-period mCVs are quite complex, with strong contributions from multipoles higher than the dipole in spite of a typical age of the white dwarfs in CVs in excess of 1 Gyr. Conclusions: .It is feasible to derive the surface field structure of an accreting white dwarf from phase-resolved low-state circular spectropolarimetry of sufficiently high signal-to-noise ratio. The fact that independent information is available on the strength and direction of the field in the accretion spot from high-state observations helps in unraveling the global field structure. Based on observations collected at the European Southern Observatory, Paranal, Chile, under programme IDs 63.P-0003(A), 64.P-0150(C), and 66.D-0128(B).

Beuermann, K.; Euchner, F.; Reinsch, K.; Jordan, S.; Gänsicke, B. T.

2007-02-01

148

Crystal structure of the blue multicopper oxidase from the white-rot fungus Trametes trogii complexed with p-toluate  

Microsoft Academic Search

A multicopper oxidase, the fungal laccase glycoenzyme from the white-rot basidiomycete fungus Trametes (Funalia) trogii, was crystallized and its crystal structure was solved at 1.58Å using molecular replacement techniques.Model refinement resulted in R-factor and R-free values of 17.4% and 19.0%, respectively. The T. trogii laccase structural model reveals the presence of a ligand bound to the T1 active site which

Irene Matera; Antonella Gullotto; Silvia Tilli; Marta Ferraroni; Andrea Scozzafava; Fabrizio Briganti

2008-01-01

149

Regulation of the brown and white fat gene programs through a PRDM16\\/CtBP transcriptional complex  

Microsoft Academic Search

Brown fat is a specialized tissue that can dissipate energy and counteract obesity through a pattern of gene expression that greatly increases mitochondrial content and uncoupled respiration. PRDM16 is a zinc-finger protein that controls brown fat determination by stimulating brown fat-selective gene expression, while suppressing the expression of genes selective for white fat cells. To determine the mechanisms regulating this

Shingo Kajimura; Patrick Seale; Takuya Tomaru; Hediye Erdjument-Bromage; Marcus P. Cooper; Jorge L. Ruas; Sherry Chin; Paul Tempst; Mitchell A. Lazar; Bruce M. Spiegelman

2008-01-01

150

White Lupin (Lupinus albus) response to phosphorus stress: evidence for complex regulation of LaSAP1  

Microsoft Academic Search

Proteoid roots are a unique adaptation that allow white lupin (Lupinus albus L. var Ultra) to survive under extreme phosphorus (P) deficient conditions. The cascade of events that signals P-deficiency\\u000a induced gene expression in proteoid roots remains unknown. Through promoter::GUS analysis we showed that expression of acid\\u000a phosphatase (LaSAP1) in P-deficient proteoid roots depends on DNA located from ?465 bp to

Kelly E. Zinn; Junqi Liu; Deborah L. Allan; Carroll P. Vance

2009-01-01

151

"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

152

Enhancing genetic mapping of complex genomes through the design of highly-multiplexed SNP arrays: application to the large and unsequenced genomes of white spruce and black spruce  

PubMed Central

Background To explore the potential value of high-throughput genotyping assays in the analysis of large and complex genomes, we designed two highly multiplexed Illumina bead arrays using the GoldenGate SNP assay for gene mapping in white spruce (Picea glauca [Moench] Voss) and black spruce (Picea mariana [Mill.] B.S.P.). Results Each array included 768 SNPs, identified by resequencing genomic DNA from parents of each mapping population. For white spruce and black spruce, respectively, 69.2% and 77.1% of genotyped SNPs had valid GoldenGate assay scores and segregated in the mapping populations. For each of these successful SNPs, on average, valid genotyping scores were obtained for over 99% of progeny. SNP data were integrated to pre-existing ALFP, ESTP, and SSR markers to construct two individual linkage maps and a composite map for white spruce and black spruce genomes. The white spruce composite map contained 821 markers including 348 gene loci. Also, 835 markers including 328 gene loci were positioned on the black spruce composite map. In total, 215 anchor markers (mostly gene markers) were shared between the two species. Considering lineage divergence at least 10 Myr ago between the two spruces, interspecific comparison of homoeologous linkage groups revealed remarkable synteny and marker colinearity. Conclusion The design of customized highly multiplexed Illumina SNP arrays appears as an efficient procedure to enhance the mapping of expressed genes and make linkage maps more informative and powerful in such species with poorly known genomes. This genotyping approach will open new avenues for co-localizing candidate genes and QTLs, partial genome sequencing, and comparative mapping across conifers.

Pavy, Nathalie; Pelgas, Betty; Beauseigle, Stephanie; Blais, Sylvie; Gagnon, France; Gosselin, Isabelle; Lamothe, Manuel; Isabel, Nathalie; Bousquet, Jean

2008-01-01

153

Sand dunes as migrating strings.  

PubMed

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

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

2013-05-01

154

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

155

Submarine sand sampler  

Microsoft Academic Search

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

Casciano

1980-01-01

156

Oil from tar sands  

Microsoft Academic Search

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

Farouq Ali

1968-01-01

157

VNIR reflectance spectra of gypsum mixtures for comparison with White Sands National Monument, New Mexico (WSNM) dune samples as an analog study of the Olympia Undae region of Mars  

NASA Astrophysics Data System (ADS)

Dunes at WSNM are being used as an analog study area for gypsum-rich dunes near the northern polar region of Mars. Samples were collected from 4 dunes at WSNM for this study. In order to determine abundances of the gypsum, quartz and dolomite present in the dune sand, size separates (<45, 45-90, 90-150, 150-250, >250 ?m) were prepared for gypsum, quartz and dolomite, mixtures were prepared using the 90-150 ?m size fraction, and all samples were characterized in the lab. Analyses of the VNIR spectral data are presented here (Figs. 1-2) and analyses of the XRD data are presented in a companion abstract [1]. The majority of the dune sand is dominated by gypsum, while the coarse grains at some ripples are largely dolomite. Mid-IR spectra will be evaluated as well. Gypsum/Dolomite Mixtures (Fig. 1) There is a clear progression of albedo and band strength in these mixture spectra as one mineral is increased and the other decreased. The mixture spectra are dominated by the gypsum bands for mixtures that are gypsum rich (?50wt.% gypsum) including a triplet at 1.446-1.535 ?m, plus bands at 1.749, 1.945, 2.217 and 2.267 ?m. When mixtures become predominantly dolomite (10/90 & 20/80 mixtures), the gypsum bands are significantly weaker, while the dolomite band at 2.322 becomes much more visible. Gypsum/Quartz Mixtures (Fig. 2) The gypsum/quartz mixture spectra are dominated to an even greater extent by gypsum, resulting in readily observable gypsum features for spectra of samples with only 10 wt.% gypsum. [1] Lafuente et al. (2013) AGU, submitted.

King, S. J.; Bishop, J. L.; Fenton, L. K.; Lafuente, B.; Garcia, G. C.; Horgan, B. H.

2013-12-01

158

Bonded-Sand/Loose-Sand Composite Mold.  

National Technical Information Service (NTIS)

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

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

1992-01-01

159

Basaltic island sand provenance  

SciTech Connect

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

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

1992-01-01

160

Laboratory Testing of Repellents against the Sand Fly Phlebotomus papatasi (Diptera: Psychodidae).  

National Technical Information Service (NTIS)

Eight topical repellants and a synthetic Pyrethroid were evaluated against the old world sand fly Phlebotomus Papatasi, using a dose-response testing procedure on white rabbits. The decreasing order of repellant effectiveness based on the median effective...

R. A. Wirtz E. D. Rowton J. A. Hallam P. V. Perkins L. C. Rutledge

1986-01-01

161

A study of morphology, provenance, and movement of desert sand seas in Africa, Asia, and Australia  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Examination of sand samples from both dune and interdune areas at White Sands, New Mexico, indicates marked differences in composition and texture between these two types of facies. If these differences are characteristics of dune fields in general, information concerning them may help to explain the contrast in appearance of the two kinds of sand areas on ERTS imagery and to permit interpretation of similar features in remote areas, such as Saudi Arabia.

Mckee, E. D.; Breed, C. S.; Harris, L. F. (principal investigators)

1973-01-01

162

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

163

The Flow of Sand.  

ERIC Educational Resources Information Center

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

Yersel, Metin

2000-01-01

164

Qualifying tight sands  

SciTech Connect

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

Harbert, T.

1981-11-01

165

Sand Wave Study.  

National Technical Information Service (NTIS)

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

A. DeVisser

1997-01-01

166

Sand on the Move  

NSDL National Science Digital Library

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

167

Great Sand Dunes.  

National Technical Information Service (NTIS)

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

1994-01-01

168

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

169

Sand Grain Observations  

NSDL National Science Digital Library

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

Twin Cities Public Television, Inc.

2006-01-01

170

Some aspects of the chemistry of Alberta oil sand bitumen  

Microsoft Academic Search

The vast oil sand formations of northern Alberta contain a broad variety of organic substances ranging from methane to complex polymeric materials with mw in excess of 10,000. Among the gaseous and volatile materials, methane and curiously neopentane and acetaldehyde predominate. From the low temperature thermal behavior of the oil sand it is concluded that these compounds were formed via

1976-01-01

171

Deviatoric Stress Response Envelopes from Multiaxial Tests on Sand  

NASA Astrophysics Data System (ADS)

Sets of rosettes of stress probes have been performed on Hostun sand in a flexible boundary true triaxial apparatus. These have shown the effect of stress history on the local distortional stiffness of the sand. Histories have included isotropic compression, and deviatoric paths with increasingly complex shapes.

Wood, D.; Sadek, T.; Dihoru, L.; Lings, ML.; Javaheri, H.

172

Transcription Factors in Light and Circadian Clock Signaling Networks Revealed by Genomewide Mapping of Direct Targets for Neurospora White Collar Complex ?†  

PubMed Central

Light signaling pathways and circadian clocks are inextricably linked and have profound effects on behavior in most organisms. Here, we used chromatin immunoprecipitation (ChIP) sequencing to uncover direct targets of the Neurospora crassa circadian regulator White Collar Complex (WCC). The WCC is a blue-light receptor and the key transcription factor of the circadian oscillator. It controls a transcriptional network that regulates ?20% of all genes, generating daily rhythms and responses to light. We found that in response to light, WCC binds to hundreds of genomic regions, including the promoters of previously identified clock- and light-regulated genes. We show that WCC directly controls the expression of 24 transcription factor genes, including the clock-controlled adv-1 gene, which controls a circadian output pathway required for daily rhythms in development. Our findings provide links between the key circadian activator and effectors in downstream regulatory pathways.

Smith, Kristina M.; Sancar, Gencer; Dekhang, Rigzin; Sullivan, Christopher M.; Li, Shaojie; Tag, Andrew G.; Sancar, Cigdem; Bredeweg, Erin L.; Priest, Henry D.; McCormick, Ryan F.; Thomas, Terry L.; Carrington, James C.; Stajich, Jason E.; Bell-Pedersen, Deborah; Brunner, Michael; Freitag, Michael

2010-01-01

173

Interaction between shrimp and white spot syndrome virus through PmRab7-VP28 complex: an insight using simulation and docking studies.  

PubMed

White spot disease is a devastating disease of shrimp Penaeus monodon in which the shrimp receptor protein PmRab7 interacts with viral envelop protein VP28 to form PmRab7-VP28 complex, which causes initiation of the disease. The molecular mechanism implicated in the disease, the dynamic behavior of proteins as well as interaction between both the biological counterparts that crafts a micro-environment feasible for entry of virus into the shrimp is still unknown. In the present study, we applied molecular modeling (MM), molecular dynamics (MD) and docking to compute surface mapping of infective amino acid residues between interacting proteins. Our result showed that ?-helix of PmRab7 (encompassing Ser74, Ile143, Thr184, Arg53, Asn144, Thr184, Arg53, Arg79) interacts with ?-sheets of VP28 (containing Ser74, Ile143, Thr184, Arg53, Asn144, Thr184, Arg53, Arg79) and Arg69-Ser74, Val75-Ile143, Leu73-Ile143, Arg79-Asn144, Ala198-Ala182 bonds contributed in the formation of PmRab7-VP28 complex. Further studies on the amino acid residues and bonds may open new possibilities for preventing PmRab7-VP28 complex formation, thus reducing chances of WSD. The quantitative predictions provide a scope for experimental testing in future as well as endow with a straightforward evidence to comprehend cellular mechanisms underlying the disease. PMID:23179770

Verma, Arunima Kumar; Gupta, Shipra; Verma, Sharad; Mishra, Abha; Nagpure, N S; Singh, Shivesh Pratap; Pathak, Ajey Kumar; Sarkar, Uttam Kumar; Singh, Shri Prakash; Singh, Mahender; Seth, Prahlad Kishore

2013-03-01

174

Kinetic Parameters of Secondary Carbide Precipitation in High-Cr White Iron Alloyed by Mn-Ni-Mo-V Complex  

NASA Astrophysics Data System (ADS)

This study presents kinetics of precipitation of secondary carbides in 14.55%Cr-Mn-Ni-Mo-V white cast iron during the destabilization heat treatment. The as-cast iron was heat treated at temperatures in the range of 800-1100 °C with soaking up to 6 h. Investigation was carried out by optical and electron microscopy, dilatometric analysis, Ms temperature measurement, and bulk hardness evaluation. TTT-curve of precipitation process of secondary carbides (M7C3, M23C6, M3C2) has been constructed in this study. It was determined that the precipitation occurs at the maximum rate at 950 °C where the process is started after 10 s and completed within 160 min further. The precipitation leads to significant increase of Ms temperature and bulk hardness; large soaking times at destabilization temperatures cause coarsening of secondary carbides and decrease in particles number, followed by decrease in hardness. The results obtained are discussed in terms of solubility of carbon in the austenite and diffusion activation of Cr atoms. The precipitation was found to consist of two stages with activation energies of 196.5 kJ/g-mole at the first stage and 47.1 kJ/g-mole at the second stage.

Efremenko, V. G.; Chabak, Yu. G.; Brykov, M. N.

2013-05-01

175

Colorimetric analysis of water and sand samples performed on a mobile phone.  

PubMed

Analysis of water and sand samples was done by reflectance measurements using a mobile phone. The phone's screen served as light source and front view camera as detector. Reflected intensities for white, red, green and blue colors were used to do principal component analysis for classification of several compounds and their concentrations in water. Analyses of colored solutions and colorimetric reactions based on widely available chemicals were performed. Classification of iron(III), chromium(VI) and sodium salt of humic acid was observed using reflected intensities from blue and green light for concentrations 2-10mg/l. Addition of complex forming sodium salt of ethylenediaminetetraacidic acid enabled the discrimination of Cu(II) ions in the 2-10mg/l concentration range based on reflection of red light. An alternate method using test strips for copper solutions with the phone as reader also demonstrated a detection limit of 2mg/l. Analysis of As(III) from 25 to 400 ?g/l based on reflection of red light was performed utilizing the bleaching reaction of tincture of iodine containing starch. Enhanced sensitivity to low concentrations of arsenic was obtained by including reflected intensities from white light in the analysis. Model colored sand samples representing discoloration caused by the presence of arsenic in groundwater were analyzed as a complementary method for arsenic detection. PMID:21530787

Iqbal, Zafar; Bjorklund, Robert B

2011-05-30

176

The Uve1 Endonuclease Is Regulated by the White Collar Complex to Protect Cryptococcus neoformans from UV Damage  

PubMed Central

The pathogenic fungus Cryptococcus neoformans uses the Bwc1-Bwc2 photoreceptor complex to regulate mating in response to light, virulence and ultraviolet radiation tolerance. How the complex controls these functions is unclear. Here, we identify and characterize a gene in Cryptococcus, UVE1, whose mutation leads to a UV hypersensitive phenotype. The homologous gene in fission yeast Schizosaccharomyces pombe encodes an apurinic/apyrimidinic endonuclease acting in the UVDE-dependent excision repair (UVER) pathway. C. neoformans UVE1 complements a S. pombe uvde knockout strain. UVE1 is photoregulated in a Bwc1-dependent manner in Cryptococcus, and in Neurospora crassa and Phycomyces blakesleeanus that are species that represent two other major lineages in the fungi. Overexpression of UVE1 in bwc1 mutants rescues their UV sensitivity phenotype and gel mobility shift experiments show binding of Bwc2 to the UVE1 promoter, indicating that UVE1 is a direct downstream target for the Bwc1-Bwc2 complex. Uve1-GFP fusions localize to the mitochondria. Repair of UV-induced damage to the mitochondria is delayed in the uve1 mutant strain. Thus, in C. neoformans UVE1 is a key gene regulated in response to light that is responsible for tolerance to UV stress for protection of the mitochondrial genome.

Verma, Surbhi; Idnurm, Alexander

2013-01-01

177

Kentucky tar sand project  

SciTech Connect

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

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

1985-03-01

178

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

179

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

180

Lithological discrimination and correlation in oil sands using rock magnetic properties  

Microsoft Academic Search

The Lower Cretaceous McMurray Formation, which contains most of the bitumen reserves of the Athabasca oil sands, comprises uncemented quartz sands with siltstone, shale, and local ironstones. The sequential fluvial, estuarine, and marine depositional environments of the McMurray drainage basin have resulted in the complex juxtaposition of differing lithofacies. Horizontal continuity of lithofacies is limited. Sand body geometries are many

1991-01-01

181

Sedimentology and reservoir potential of Matilija sandstone: an Eocene sand-rich deep-sea fan and shallow-marine complex, California  

SciTech Connect

A deep-sea fan facies model for the Matilija Sandstone (southern California) regression from turbidite to shallow-marine to brackish deposits are documented. In addition, reservoir characteristics and the diagenetic history of the deep-sea fan complex is discussed. Despite thick, favorable source beds and generally good initial reservoir characteristics, the Matilija Sandstone is not a productive unit of the Ventura basin because of low reservoir permeability and porosity.

Link, M.H. (Cities Service Co. Research, Tulsa, OK); Welton, J.E.

1982-10-01

182

Asbestos in play sand  

SciTech Connect

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

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

1987-04-02

183

Sound-Producing Sand Avalanches  

NSDL National Science Digital Library

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

Bretz, Michael; Nori, Franco; Sholtz, Paul

2007-05-18

184

Gas fluidized sand, liquid or solid?  

NASA Astrophysics Data System (ADS)

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

Stoker, David S.; Rutgers, Maarten A.

2000-03-01

185

Does complex terrain matter for global terrestrial ecosystem models? Forest ecosystem dynamics in the White Mountains, NH. (Invited)  

NASA Astrophysics Data System (ADS)

Environmental scientists have long recognized that vegetation varies consistently at a landscape-scale due to variation in soils, hydrology, and topography. We expect that this variation to interact with climate change in complex ways, potentially allowing some species to persist in refugia while shifting other species to locations that may be edaphically unfavorable. Despite the recognized importance of this variation, it has not been incorporated into global and regional scale models because this heterogeneity occurs at a finer spatial scale than can be captured explicitly by refining model resolution. Rather than represent landscape-scale variability explicitly, we develop a spatially implicit approach to capture variation in soils, lateral hydrologic flow, and the effects of topography on microclimate and radiation interception. This scheme is incorporated in the Ecosystem Demography model. We tested this approach by first calibrating the model to forest inventory data and eddy-covariance fluxes of carbon, water, and energy from the Bartlett Experimental Forest in central NH and then validating it against 40+ years of vegetation and hydrology data from the Hubbard Brook Ecosystem Study, located 40km in forests of similar composition. When applied to Hubbard Brook the model is able to capture watershed streamflow at monthly to interannual scales and the variation in growth rates with topography, soils, and hydrology, and reproduces observed NPP during the forest growth phase. Growth rates were overestimated during the latter portion of the record, likely due to the cumulative impacts of acid rain which are not yet accounted for in the model. By sequentially switching off each source of edaphic variation, we find that the effect of elevation on microclimate has the greatest impact on the within-watershed distribution of NEE and NPP. The effects of slope and aspect on radiation are strongest at mid-elevation while lateral hydrology is most important on ridges and in valley-bottoms. A failure to include the effects of complex terrain is shown to result in a non-trivial overestimation of the net carbon sink. The model is then applied at a regional scale to forecast forest change under climate change scenarios. The addition of complex terrain is shown to buffer the effects of climate change on regional carbon fluxes. This effect occurs because climate change effects differ not only in magnitude but also in direction at a landscape-scale.

Dietze, M. C.; Richardson, A. D.; Moorcroft, P. R.

2010-12-01

186

Imaging hydraulic conductivity of a sand-gravel aquifer by means of complex resistivity tomography: A feasibility study at the Krauthausen test site using calibrated electrical-hydraulic relationships  

NASA Astrophysics Data System (ADS)

Over the past years, several studies have proven the potential of the complex resistivity (or induced polarization - IP) method for the hydraulic characterization of the subsurface. Various electrical-hydraulic relationships have been established for different soil and rock types, most of them either based on a single-frequency measurement of IP, typically in terms of imaginary conductivity, or on a quantity describing the spectral IP (SIP) response, for instance in terms of a characteristic relaxation time. In principle, such relationships open the way for the non-invasive imaging of hydraulic conductivity at the field scale using complex resistivity imaging. However, convincing field demonstrations of this methodological approach, where site-calibrated relationships obtained from laboratory measurements on sediment samples are used and where the hydraulic imaging result is validated against an independently determined hydraulic conductivity distribution, are still lacking. We here investigate the applicability of complex resistivity imaging to determine hydraulic conductivity for cross-borehole data collected at the Krauthausen test site, Germany, which presents a heterogeneous sand-gravel aquifer with four orders of magnitude variation in hydraulic conductivity. Laboratory measurements on sediment samples from the site, well representing the vertical lithological variation, show a strong correlation in form of a power-law relationship between hydraulic conductivity and a representative SIP relaxation time, while the correlation of imaginary conductivity with hydraulic conductivity is less strong and, importantly, breaks down for lower measurement frequencies (i.e., below 10 Hz). This observation suggests that it is the fine (clay) fraction which governs both hydraulic conductivity and the higher-frequency complex resistivity response of the Krauthausen aquifer material. A suitable characteristic relaxation time is given by the mean of the log relaxation time distribution as obtained from Debye decomposition of the complex resistivity spectrum, which can be computed with sufficient accuracy also directly from the first moment of the resistivity phase spectrum (i.e., from the phase-averaged mean frequency). Complex resistivity images were computed using a smoothness-constrained inversion scheme and a resistance-dependent phase data error model, and subsequently converted into hydraulic conductivity using the established electrical-hydraulic relationships. The obtained hydraulic imaging result shows remarkable agreement with the hydraulic flow pattern as previously observed at the site in the course of a solute tracer experiment by means of time-lapse electrical resistivity tomography (Müller et al., 2010, WRR) - in terms of both structure and derived pore water velocity values.

Kemna, A.; Huisman, J. A.; Flores-Orozco, A.; Zimmermann, E.; Vereecken, H.

2012-12-01

187

Oil from deep sands  

Microsoft Academic Search

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

2009-01-01

188

Sand and sandstone  

SciTech Connect

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

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

1987-01-01

189

Sand and gravel  

Microsoft Academic Search

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

J. R. Evans

1978-01-01

190

Oil sands fulfill their promise  

Microsoft Academic Search

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

Chaapel

2009-01-01

191

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

192

Sand accumulation around porous fences  

Microsoft Academic Search

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

Nabil A. Zaghloul

1997-01-01

193

White Toenails  

MedlinePLUS

... on a toenail, often causes bleeding under the nail because of blood vessels being broken. This would ... vessels, a white spot may appear under the nail. The spot will slowly grow out with the ...

194

White Dwarfs  

NASA Astrophysics Data System (ADS)

This book is based on the Proceedings of the 9th European Workshop on White Dwarfs, the most recent in a series of meetings which have become the most important events in this field. Many of the contributions, however, have been expanded considerably by the authors to include introductory material. This makes this volume a useful, up-to-date introduction into the present status of observations and theory of white dwarf stars.

Koester, Detlev; Werner, Klaus

195

Sand hazards on tourist beaches.  

PubMed

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

Heggie, Travis W

2013-01-01

196

Polar Sand Dunes  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

197

Magic Sand: Nanosurfaces  

NSDL National Science Digital Library

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

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

2012-06-26

198

Western gas sands  

SciTech Connect

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

Not Available

1985-03-01

199

Nuclear and mitochondrial subunits from the white shrimp Litopenaeus vannamei F 0 F 1 ATP-synthase complex: cDNA sequence, molecular modeling, and mRNA quantification of atp9 and atp6  

Microsoft Academic Search

We studied for the first time the ATP-synthase complex from shrimp as a model to understand the basis of crustacean bioenergetics\\u000a since they are exposed to endogenous processes as molting that demand high amount of energy. We analyzed the cDNA sequence\\u000a of two subunits of the Fo sector from mitochondrial ATP-synthase in the white shrimp Litopenaeus vannamei. The nucleus encoded

Adriana Muhlia-Almazan; Oliviert Martinez-Cruz; Fernando Garcia-Carreño; Rodrigo Arreola; Rogerio Sotelo-Mundo; Gloria Yepiz-Plascencia

2008-01-01

200

Differential splicing of COL4A5 mRNA in kidney and white blood cells: A complex mutation in the COL4A5 gene of an Alport patient deletes the NC1 domain  

Microsoft Academic Search

Differential splicing of COL4A5 mRNA in kidney and white blood cells: A complex mutation in the COL4A5 gene of an Alport patient deletes the NC1 domain. PCR conditions were optimized to amplify the COL4A5 cDNA from lymphoblasts and kidney tissue. Sequencing of the COL4A5 mRNA isolated from the kidney of an Alport syndrome patient revealed two differences with the published

Caiying Guo; Boudewijn Van Damme; Rita Van Damme-Lombaerts; Herman Van den Berghe; Jean-Jacques Cassiman; Peter Marynen

1993-01-01

201

Enhancing Simulation of Sand Behavior through 3D Subdivision Techniques  

NASA Astrophysics Data System (ADS)

Through the use of modern computer graphics, visualization and parallel computation continue to provide academic disciplines with new techniques to work with raw data. This is particularly true in the earth and planetary sciences as many researchers are using graphics hardware to process large amounts of data for analysis. Thus, there is an increasing demand for collaboration between computer graphics and the earth sciences. Recognizing this opportunity, we are collaborating with the Oregon Space Grant and IGERT Ecosystem Informatics programs to investigate new techniques for simulating the behavior of sand. In addition, we are also collaborating with the Jet Propulsion Laboratory's (JPL) DARTS Lab to exchange ideas and gain feedback on our work. The DARTS Lab specializes in planetary vehicle simulation, such as the Mars rovers. This simulation utilizes a virtual "sand box" to test how planetary rovers respond to different terrains while traversing them. Unfortunately, this simulation is unable to fully mimic the harsh, sandy environments of those found on Mars. Ideally, these simulations should allow a rover to interact with the sand beneath it, providing further insight into its performance. In particular, there may be situations where a rover may become stuck in sand due to lack of friction between the sand and wheels. Thus, we have been developing a sand simulation framework to mimic the behavior of sand. Treated naively, this is a computationally complex problem, especially if trying to represent millions or even billions of sand particles interacting with each other. However, we can use graphics processing units (GPUs) on modern graphics hardware to subdivide and parallelize the problem. Basically, our idea is to subdivide regions of sand similar to a Level of Detail (LoD) method. Put another way, the more active the sand is in interacting with outside objects, the smaller the region the sand will be represented in the simulation. For example, let's say there is a planetary rover interacting with our sand simulation. Sand that is actively interacting with a rover wheel will be represented as an individual particle whereas sand that is further under the surface will be represented by a 3D region that represents several particles. As a particle region moves closer to the surface, it subdivides into smaller regions until individual sand particles are left. Our technique uses a variation of a 3D Voronoi decomposition in order to generate regions of sand. However, in our iteration, sand on the surface will be subdivided as particles whereas sand deeper into the earth will be subdivided into subsequently larger regions. By doing this, we can represent many more particles of sand than through traditional means. In addition, we have the added benefit of being able to parallelize the interaction between active particles through the use of the GPU. As such, not only are we able to represent vast amounts of sand, but we can also utilize more individual particles at the interaction source. An enhanced sand model through the use of subdivision techniques and GPUs has great potential for earth science research. Our collaborations with JPL have helped to further refine our simulation framework. As a result, we feel this work could also benefit other earth science fields, such as understanding sinkholes and debris flows.

Clothier, M.; Bailey, M.

2011-12-01

202

Sand dollar sites orogenesis  

NASA Astrophysics Data System (ADS)

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

Amos, Dee

2013-04-01

203

Imperial Sand Dunes  

NSDL National Science Digital Library

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

204

Deceleration of projectiles in sand  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

205

White Pelican  

NSDL National Science Digital Library

The American white pelican is still considered endangered in Alberta, Canada, where the population is increasing but fewer than half of the 20 known historic nesting islands are still in use. The site provides information on this magnificent bird: habitat, general biological data, risk factors, and management. External links to Canadian parks, nonprofit groups, and other species profiles also included.

Rasmussen, Ray

2011-02-03

206

A new class of gadolinium complexes employed to obtain high-phasing-power heavy-atom derivatives: results from SAD experiments with hen egg-white lysozyme and urate oxidase from Aspergillus flavus.  

PubMed

Seven gadolinium complexes are shown to be excellent compounds for the preparation of heavy-atom derivatives for macromolecular crystallography projects. De novo phasing has been carried out using single-wavelength anomalous diffraction (SAD) on a series of gadolinium-derivative crystals of two proteins: hen egg-white lysozyme and urate oxidase from Aspergillus flavus. Lysozyme derivative crystals were obtained by co-crystallizing the protein with the corresponding gadolinium complex at a concentration of 100 mM. Diffraction data were collected to a resolution of 1.7 A using Cu K(alpha) radiation from a rotating-anode generator, making use of the high anomalous signal of gadolinium at this wavelength. Urate oxidase derivative crystals were obtained by soaking native crystals in 100 mM gadolinium complex solutions. Diffraction data were collected to a resolution close to 3 A using X-rays at the Gd L(III) absorption edge, taking advantage of the sharp white line on that edge. For all urate oxidase derivative crystals and three of the lysozyme crystals, SAD phasing led to electron-density maps of very high quality, allowing unambiguous chain tracing. From this study, the binding effectiveness of the gadolinium complexes seems to be related to the nature of the precipitant used for crystallization. These gadolinium complexes represent a new class of high-phasing-power heavy-atom derivatives that may be used for high-throughput structure-determination projects. PMID:12499547

Girard, E; Stelter, M; Anelli, P L; Vicat, J; Kahn, R

2003-01-01

207

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

SciTech Connect

The Olcese Sand near Bakersfield, California, contains evidence of a range of paleoenvironments including nonmarine, estuarine, and outer shelf depositional settings. Foraminifera from surface and subsurface samples place the Olcese in the Saucesian and Relizian of the California benthic stages. A pumice bed in the Olcese has been dated by fission track methods at 15.5 Ma. The Olcese Sand interfingers with the underlying Freeman Silt and the overlying Round Mountain Silt. In the type area, in Round Mountain oil field, the Olcese is 300-360 m thick. The Olcese is subdivided into three environmental facies. In the Knob Hill Quadrangle, the lower Olcese consists of (1) thinly bedded to blocky white tuffaceous silt and sand, or (2) planar cross-bedded fine to coarse-grained sand with pumice pebbles lining the bedding surfaces. Fossil mollusks and skate teeth indicate a shallow marine environment for the lower Olcese. Although the Olcese is predominantly a marine unit, the middle Olcese is nonmarine, with lenses of marine deposition. The middle Olcese is well exposed in the Knob Hill, Oil Center, and Rio Bravo Ranch Quadrangles, and is characterized by fine to coarse sand with occasional gravel lenses, strong cross-bedding, and a blue-gray color. The upper Olcese is a very fine to medium-grained, marine sand that fines upward into a sandy siltstone southward toward the Kern River. Foraminifera and mollusks from outcrops in the Rio Bravo Ranch Quadrangle indicate outer shelf to estuarine environments for the upper Olcese. The varying environments in the Olcese Sand reflect slight but frequent fluctuations in water depth and can be used to interpret the basin-margin history.

Olson, H.C.

1986-04-01

208

Assessing the Martian Surface Distribution of Aeolian Sand using a Mars General Circulation Model  

NASA Technical Reports Server (NTRS)

A sand transport model using White's sand flux equation and the Mars beneral circulation model was developed to understand the erosional sources, transport pathways, and depositional sinks of windblown sand on Mars. An initially uniform distribution of sand (4 mm over the entire surface) is reeionally transported based on wind stress, saltation threshold, and percentage of topogaphic trapping. Results are consistsnt with the , observed polar and Hellespontus dunes and Christensen's madeled block size distribution, butonly for an extremely law saltation threshold (0.024 N/sq m): Low thresholds generally result in transport of sand-sized particles originating in the northern mid latitudes to the north pole, and transport from the northern lower latitudes to the southern hemisphere. Our results indicate that the polar dune fields could form in 50,000 years, consistent with the active polar dunes and lack of longitudinal dunes observed on the surface of Mars.

Anderson, F. S.; Greeley, R.; Xu, P.; Lo, E.; Blumberg, D. G.; Haberle, R. M.; Murphy, J. R.

1999-01-01

209

Vacuum Head Removes Sanding Dust  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

210

Sand and Dust on Mars  

NASA Technical Reports Server (NTRS)

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

Greeley, Ronald; Haberle, Robert M.

1991-01-01

211

Sand pictures : what's missing?  

NSDL National Science Digital Library

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

National Council of Teachers of Mathematics (NCTM)

2002-01-01

212

Aging of Athabasca oil sand  

SciTech Connect

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

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

1988-06-01

213

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

214

MAJOR-HISTOCOMPATIBILITY-COMPLEX-ASSOCIATED VARIATION IN SECONDARY SEXUAL TRAITS OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS): EVIDENCE FOR GOOD-GENES ADVERTISEMENT  

Microsoft Academic Search

Good-genes hypotheses predict that development of secondary sexual characters can be an honest adver- tisement of heritable male quality. We explored this hypothesis using a cervid model (adult, male white-tailed deer, Odocoileus virginianus) to determine whether antler development could provide an honest signal of a male's genetic quality and condition to adversaries. We compared antler, morphometric, hormonal, and parasitic data

Stephen S. Ditchkoff; Robert L. Lochmiller; Ronald E. Masters; Steven R. Hoofer; Ronald A. Van Den Bussche

2001-01-01

215

Augmenting Sand Simulation Environments through Subdivision and Particle Refinement  

NASA Astrophysics Data System (ADS)

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

Clothier, M.; Bailey, M.

2012-12-01

216

Geology of the athabasca oil sands.  

PubMed

In-place bitumen resources in the Alberta oil sands are estimated at 1350 billion barrels. Open-pit mining and hot water extraction methods, which involve the handling of huge tonnages of earth materials, are being employed in the two commercial plants now operating. In situ recovery methods will be required to tap the 90 percent of reserves that are too deeply buried to be surface mined. Development of in situ technologies will be painstaking and expensive, and success will hinge on their compatibility with extremely complex geological conditions in the subsurface. PMID:17809090

Mossop, G D

1980-01-11

217

Geology of the Athabasca oil sands  

NASA Astrophysics Data System (ADS)

In-place bitumen resources in the Alberta oil sands are estimated at 1350 billion barrels. Open-pit mining and hot water extraction methods, which involve the handling of huge tonnages of earth materials, are being employed in the two commercial plants now operating. In situ recovery methods will be required to tap the 90 percent of reserves that are too deeply buried to be surface mined. Development of in situ technologies will be painstaking and expensive, and success will hinge on their compatibility with extremely complex geological conditions in the subsurface.

Mossop, G. D.

1980-01-01

218

Geology of the Athabasca oil sands  

SciTech Connect

In-place bitumen resources in the Alberta oil sands are estimated at 1350 billion barrels. Open-pit mining and hot water extraction methods, which involve the handling of huge tonnages of earth materials, are being employed in the two commercial plants now operating. In situ recovery methods will be required to tap the 90% of reserves that are too deeply buried to be surface mined. Development of in situ technologies will be painstaking and expensive, and success will hinge on their compatibility with extremely complex geological conditions in the subsurface. 10 figures.

Mossop, G.D.

1980-01-11

219

Advanced Techniques for Simulating the Behavior of Sand  

NASA Astrophysics Data System (ADS)

Computer graphics and visualization techniques continue to provide untapped research opportunities, particularly when working with earth science disciplines. Through collaboration with the Oregon Space Grant and IGERT Ecosystem Informatics programs we are developing new techniques for simulating sand. In addition, through collaboration with the Oregon Space Grant, we’ve been communicating with the Jet Propulsion Laboratory (JPL) to exchange ideas and gain feedback on our work. More specifically, JPL’s DARTS Laboratory specializes in planetary vehicle simulation, such as the Mars rovers. This simulation utilizes a virtual "sand box" to test how planetary rovers respond to different terrains while traversing them. Unfortunately, this simulation is unable to fully mimic the harsh, sandy environments of those found on Mars. Ideally, these simulations should allow a rover to interact with the sand beneath it, particularly for different sand granularities and densities. In particular, there may be situations where a rover may become stuck in sand due to lack of friction between the sand and wheels. In fact, in May 2009, the Spirit rover became stuck in the Martian sand and has provided additional motivation for this research. In order to develop a new sand simulation model, high performance computing will play a very important role in this work. More specifically, graphics processing units (GPUs) are useful due to their ability to run general purpose algorithms and ability to perform massively parallel computations. In prior research, simulating vast quantities of sand has been difficult to compute in real-time due to the computational complexity of many colliding particles. With the use of GPUs however, each particle collision will be parallelized, allowing for a dramatic performance increase. In addition, spatial partitioning will also provide a speed boost as this will help limit the number of particle collision calculations. However, since the goal of this research is to simulate the look and behavior of sand, this work will go beyond simple particle collision. In particular, we can continue to use our parallel algorithms not only on single particles but on particle “clumps” that consist of multiple combined particles. Since sand is typically not spherical in nature, these particle “clumps” help to simulate the coarse nature of sand. In a simulation environment, multiple combined particles could be used to simulate the polygonal and granular nature of sand grains. Thus, a diversity of sand particles can be generated. The interaction between these particles can then be parallelized using GPU hardware. As such, this research will investigate different graphics and physics techniques and determine the tradeoffs in performance and visual quality for sand simulation. An enhanced sand model through the use of high performance computing and GPUs has great potential to impact research for both earth and space scientists. Interaction with JPL has provided an opportunity for us to refine our simulation techniques that can ultimately be used for their vehicle simulator. As an added benefit of this work, advancements in simulating sand can also benefit scientists here on earth, especially in regard to understanding landslides and debris flows.

Clothier, M.; Bailey, M.

2009-12-01

220

Studies of Phlebotomine Sand Flies.  

National Technical Information Service (NTIS)

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

D. G. Young G. B. Fairchild

1973-01-01

221

Deceleration of Projectiles in Sand  

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

222

Spherical Waves in Saturated Sand.  

National Technical Information Service (NTIS)

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

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

1996-01-01

223

Sand Reclamation Concept Definition Study.  

National Technical Information Service (NTIS)

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

M. Granlund

1990-01-01

224

Lipid, Fatty Acid and energy density profiles of white sharks: insights into the feeding ecology and ecophysiology of a complex top predator.  

PubMed

Lipids are major sources of metabolic energy in sharks and are closely linked to environmental conditions and biological cycles, such as those related to diet, reproduction and migration. In this study, we report for the first time, the total lipid content, lipid class composition and fatty acid profiles of muscle and liver tissue of white sharks, Carcharodon carcharias, of various lengths (1.5-3.9 m), sampled at two geographically separate areas off southern and eastern Australia. Muscle tissue was low in total lipid content (<0.9% wet mass, wm) and was dominated by phospholipids (>90% of total lipid) and polyunsaturated fatty acids (34±12% of total fatty acids). In contrast, liver was high in total lipid which varied between 51-81% wm and was dominated by triacylglycerols (>93%) and monounsaturated fatty acids (36±12%). With knowledge of total lipid and dry tissue mass, we estimated the energy density of muscle (18.4±0.1 kJ g-1 dm) and liver (34.1±3.2 kJ g-1 dm), demonstrating that white sharks have very high energetic requirements. High among-individual variation in these biochemical parameters and related trophic markers were observed, but were not related to any one biological or environmental factor. Signature fatty acid profiles suggest that white sharks over the size range examined are generalist predators with fish, elasmobranchs and mammalian blubber all contributing to the diet. The ecological applications and physiological influences of lipids in white sharks are discussed along with recommendations for future research, including the use of non-lethal sampling to examine the nutritional condition, energetics and dietary relationships among and between individuals. Such knowledge is fundamental to better understand the implications of environmental perturbations on this iconic and threatened species. PMID:24871223

Pethybridge, Heidi R; Parrish, Christopher C; Bruce, Barry D; Young, Jock W; Nichols, Peter D

2014-01-01

225

Lipid, Fatty Acid and Energy Density Profiles of White Sharks: Insights into the Feeding Ecology and Ecophysiology of a Complex Top Predator  

PubMed Central

Lipids are major sources of metabolic energy in sharks and are closely linked to environmental conditions and biological cycles, such as those related to diet, reproduction and migration. In this study, we report for the first time, the total lipid content, lipid class composition and fatty acid profiles of muscle and liver tissue of white sharks, Carcharodon carcharias, of various lengths (1.5–3.9 m), sampled at two geographically separate areas off southern and eastern Australia. Muscle tissue was low in total lipid content (<0.9% wet mass, wm) and was dominated by phospholipids (>90% of total lipid) and polyunsaturated fatty acids (34±12% of total fatty acids). In contrast, liver was high in total lipid which varied between 51–81% wm and was dominated by triacylglycerols (>93%) and monounsaturated fatty acids (36±12%). With knowledge of total lipid and dry tissue mass, we estimated the energy density of muscle (18.4±0.1 kJ g?1 dm) and liver (34.1±3.2 kJ g?1 dm), demonstrating that white sharks have very high energetic requirements. High among-individual variation in these biochemical parameters and related trophic markers were observed, but were not related to any one biological or environmental factor. Signature fatty acid profiles suggest that white sharks over the size range examined are generalist predators with fish, elasmobranchs and mammalian blubber all contributing to the diet. The ecological applications and physiological influences of lipids in white sharks are discussed along with recommendations for future research, including the use of non-lethal sampling to examine the nutritional condition, energetics and dietary relationships among and between individuals. Such knowledge is fundamental to better understand the implications of environmental perturbations on this iconic and threatened species.

Pethybridge, Heidi R.; Parrish, Christopher C.; Bruce, Barry D.; Young, Jock W.; Nichols, Peter D.

2014-01-01

226

Modelling of saturated sand flux  

NASA Astrophysics Data System (ADS)

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

Durán, O.; Herrmann, H.

2006-07-01

227

Induced polarization signatures of cations exhibiting differential sorption behaviors in saturated sands  

Microsoft Academic Search

Two sets of experiments were designed to understand the change in induced polarization associated with the sorption of copper and sodium, exhibiting distinct sorption behavior on a silica sand. A sand column experiment was first performed to see the change in the complex conductivity during the advective transport of a copper sulfate solution. A second set of experiments was done

P. Vaudelet; A. Revil; M. Schmutz; M. Franceschi; P. Bégassat

2011-01-01

228

Tar sands. (FL74-56)  

Microsoft Academic Search

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

1974-01-01

229

Alberta's oil sands in-situ pilots  

SciTech Connect

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

Phillips, R.S.

1981-01-01

230

Behavior of cemented sands - I. Testing  

Microsoft Academic Search

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

Ali A. Abdulla; Panos D. Kiousis

1997-01-01

231

Nematodes Infect, But Do Not Manipulate Digging By, Sand Crabs, Lepidopa benedicti  

PubMed Central

We examined sand crabs (Lepidopa benedicti) for endoparasites, and found the only parasite consistently infecting the studied population were small nematodes. Because many nematodes have complex life cycles involving multiple hosts, often strongly manipulating their hosts, we hypothesized that nematodes alter the behavior of their sand crab hosts. We predicted that more heavily infected crabs would spend more time above sand than less heavily infected crabs. Our data indicate infection by nematodes was not correlated with duration of time crabs spent above sand. We also suggest that organisms living in sandy beaches may benefit from relatively low parasite loads due to the low diversity of species in the habitat.

Joseph, Meera; Faulkes, Zen

2014-01-01

232

Observations of Sand Transport Processes Over Sorted Bedforms  

NASA Astrophysics Data System (ADS)

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

Traykovski, P.

2005-05-01

233

Colorimetric analysis of water and sand samples performed on a mobile phone  

Microsoft Academic Search

Analysis of water and sand samples was done by reflectance measurements using a mobile phone. The phone's screen served as light source and front view camera as detector. Reflected intensities for white, red, green and blue colors were used to do principal component analysis for classification of several compounds and their concentrations in water. Analyses of colored solutions and colorimetric

Zafar Iqbal; Robert B. Bjorklund

2011-01-01

234

Archeological Reconnaissance of Two Possible Sites of the Sand Creek Massacre of 1864.  

National Technical Information Service (NTIS)

The purpose of this document is to report the efforts to establish the location of the Sand Creek Massacre. It was one of the most significant events in Colorado history and is one of the most important events in the history o Indian/White relations on th...

D. D. Scott A. W. Bond R. Ellis W. B. Lees

1998-01-01

235

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

236

Coastal dune facies, Permian Cutler Formation (White Rim Sandstone), Capitol Reef National Park area, southern Utah  

NASA Astrophysics Data System (ADS)

The Permian Cutler Formation (White Rim Sandstone) in the Capitol Reef National Park area in southern Utah is an excellent example of a coastal dune complex subjected to periodic flooding by marine waters. Wind-ripple, grainfall and grainflow laminae compose the cross-sets deposited by eolian dunes. However, wave-reworked structures such as oscillation ripples, the occurrence of the characteristically marine trace fossils Thalassinoides and Chondrites, and interfingering marine carbonate beds of the Kaibab Formation collectively indicate marine interaction with the eolian environment. Four facies are distinguished: cross-stratified sandstone, burrowed to bioturbated sandstone, brecciated and deformed sandstone, and ripple-laminated sandstone and thin carbonate beds. One unusual aspect of the cross-stratified sandstone facies is the abundance of coarse-grained sand. Coarse-grained sand is atypical in many ancient eolian slipface deposits, but occurs here in large slipface foresets as both grainflow and wind-ripple deposits. No water-laid structures are found in these slipface deposits. Coarse-grained sand was probably transported to the Cutler shoreline by fluvial systems draining the Uncompahgre Uplift to the east, and then concentrated as coarse-grained ripples in interdune areas. Some of these coarse-grained ripples migrated up the stoss side of the dunes and accumulations of coarse-grained sand avalanched down the crest to form grainflow deposits. An extensive amount of soft-sediment deformation is indicated by the presence of convolute bedding and brecciation. These features occur near the zone of interfingering with marine carbonate beds of the Kaibab Formation. The water-saturated and moist conditions required for extensive deformation may have been controlled by the proximity of these sandstones to the shoreline, and fluctuations in the associated groundwater table.

Kamola, Diane L.; Chan, Marjorie A.

1988-04-01

237

Sand Density as Sandpile Descriptor  

NASA Astrophysics Data System (ADS)

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

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

238

How to estimate bidirectional wind conditions using isolated sand dunes  

NASA Astrophysics Data System (ADS)

Sand dunes are shaped by the effect of wind on sand particles. While sand dunes under unidirectional wind have been used for indicators of the dominant wind direction, it has been difficult to use sand dunes formed by more complex wind conditions (e.g. bidirectional wind regime)to estimate the wind conditions. We focused on isolated sand dunes as a candidate of the indicator of bidirectional wind conditions because continuous dunes (longitudinal dunes) could not show the directions and durations of two flows when the amounts of the sand transported in two wind directions were not even. We conducted flume experiments that generated periodically bidirectional and oblique flows, and found that dune topographies were controlled by two elements under these conditions. The most important factor was the angle between the two flow directions, which determined both the nature of change in the crest line following the change in flow direction and the resultant topography. The second factor was the event duration ratio of the two flows, which influenced the curvature of the crest line. We propose a new phase diagram of the morphological development of isolated dunes under bidirectional flow conditions driven by differences in flow angle and duration. Our phase diagram could distinquish flow conditions of all types of sand topographies, while the exiting diagram using RDP/DP could not. And our diagram have higher angular resolution than that using continuous dunes. Moreover, the estimation of bidirectional wind regime using our phase diagram agree with data from a natural dune field in the Western Sahara where the wind regime is well understood.

Taniguchi, K.; Endo, N.

2012-12-01

239

Windblown Sand in West Candor  

NASA Technical Reports Server (NTRS)

23 December 2003

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

2004-01-01

240

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

241

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

242

Three-dimensional structure of the tetragonal crystal form of egg-white avidin in its functional complex with biotin at 2.7 A resolution.  

PubMed

The three-dimensional structure of hen egg-white avidin, crystallized in a tetragonal crystal form, has been solved at 2.7 A resolution by molecular replacement methods. After refinement the crystallographic R-factor is 16.8%, for the 7255 reflections in the 10.0 to 2.7 A resolution range. The asymmetric unit contains two avidin polypeptide chains (M(r) 2 x 15,600), which build up the functional tetramer through a crystallographic 2-fold axis parallel to the c unit cell direction. The avidin tetramer has almost exact 222 molecular symmetry; the three possible dimers display quite distinct packing interfaces. Each protomer is organized in an eight-stranded antiparallel orthogonal beta-barrel, with extended loop regions. The avidin binding site within each promoter is located in a deep pocket, at the center of the barrel, displaying both hydrophobic and polar residues for recognition of the tightly bound vitamin. Two Trp residues, Trp70 and Trp97, and Phe79 are in close contact with biotin. Moreover, the binding pocket is partly closed in its outer rim by residue Trp110 of a neighboring subunit. Once bound, biotin is almost completely buried in the protein core, with the exception of the valeryl side-chain carboxylate group which is exposed to solvent, hydrogen bonds to residues Ala39, Thr40 and Ser75, and triggers the formation of a network of hydrogen bonded water molecules. Modeling of synthetic biotin analogues allows us to rationalize functional data available for the binding of these compounds, and to analyze them in terms of biotin recognition mechanism. Hen egg-white avidin shows clear structural homology to streptavidin, from Streptomyces avidinii, but significant deviations can be observed in some regions. PMID:8515446

Pugliese, L; Coda, A; Malcovati, M; Bolognesi, M

1993-06-01

243

The role of suspended load transport in the occurrence of tidal sand waves  

NASA Astrophysics Data System (ADS)

sand waves are dynamic bed patterns which are formed by the complex interaction between hydrodynamics, sediment transport, and geomorphology. Field data from the southern North Sea reveal that sand waves are absent where suspended load transport is the dominant transport mode. In order to understand the mechanisms responsible for the absence of sand waves, we study the influence of suspended load transport on the formation of tidal sand waves with a numerical process-based geomorphological model (Delft3D). Model simulations are presented in which the vertical eddy viscosity and sediment diffusivity are both spatially and temporally variable (k-? turbulence model). First, it is shown that the preferred wavelength of sand waves for a relatively large grain size increases by the inclusion of suspended sediment, while for a relatively small grain size the flat bed is stable and no sand waves evolve. Second, it is shown that suspended load transport causes the suppression of long sand waves, resulting in a finite range of wavelengths that experience growth. Finally, by varying flow velocity amplitude and grain size, critical conditions for sand wave formation are found, i.e., conditions for which sand waves are marginally generated.

Borsje, B. W.; Kranenburg, W. M.; Roos, P. C.; Matthieu, J.; Hulscher, S. J. M. H.

2014-04-01

244

White Light Interferometry  

Microsoft Academic Search

White light interferometry is an extremely powerful tool for optical measurements. This paper discusses the advantages and disadvantages of white light interferometry compared to laser light interferometry. Three different white light interferometers are discussed; 1. diffraction grating interferometers, 2. vertical scanning or coherence probe interferometers, and 3. white light scatterplate interferometers.

James C. Wyant

2002-01-01

245

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

SciTech Connect

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

Kohl, B.

1985-02-01

246

Policy Analysis of Water Availability and Use Issues for Domestic Oil Shale and Oil Sands Development  

SciTech Connect

Oil shale and oil sands resources located within the intermountain west represent a vast, and as of yet, commercially untapped source of energy. Development will require water, and demand for scarce water resources stands at the front of a long list of barriers to commercialization. Water requirements and the consequences of commercial development will depend on the number, size, and location of facilities, as well as the technologies employed to develop these unconventional fuels. While the details remain unclear, the implication is not – unconventional fuel development will increase demand for water in an arid region where demand for water often exceeds supply. Water demands in excess of supplies have long been the norm in the west, and for more than a century water has been apportioned on a first-come, first-served basis. Unconventional fuel developers who have not already secured water rights stand at the back of a long line and will need to obtain water from willing water purveyors. However, uncertainty regarding the nature and extent of some senior water claims combine with indeterminate interstate river management to cast a cloud over water resource allocation and management. Quantitative and qualitative water requirements associated with Endangered Species protection also stand as barriers to significant water development, and complex water quality regulations will apply to unconventional fuel development. Legal and political decisions can give shape to an indeterminate landscape. Settlement of Northern Ute reserved rights claims would help clarify the worth of existing water rights and viability of alternative sources of supply. Interstate apportionment of the White River would go a long way towards resolving water availability in downstream Utah. And energy policy clarification will help determine the role oil shale and oil sands will play in our nation’s future.

Ruple, John; Keiter, Robert

2010-12-31

247

Tar sands and oil shales  

Microsoft Academic Search

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

de Never

1966-01-01

248

Geology on a Sand Budget  

ERIC Educational Resources Information Center

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

Kane, Jacqueline

2004-01-01

249

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

250

Studies of Phlebotomine Sand Flies.  

National Technical Information Service (NTIS)

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

D. G. Young

1981-01-01

251

Technology Assessment of Intermittent Sand Filters.  

National Technical Information Service (NTIS)

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

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

1985-01-01

252

Loose sand habitat at the Mojave desert  

NSDL National Science Digital Library

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

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

2007-01-06

253

The Permian Weissliegend of NW Europe: The partial deformation of aeolian dune sands caused by the Zechstein transgression  

NASA Astrophysics Data System (ADS)

The Weissliegend is a European sandstone unit of largely late Early Permian age. It is underlain by the Early Permian Rotliegend red desert sandstones and is overlain by the conventionally accepted basal bed of the Zechstein-the bituminous marine shales of the Kupferschiefer. The Weissliegend sandstones are characteristically white or grey in colour and have been recognised beneath the North Sea, in Germany and in Poland. Equivalents, which are red or yellow in colour, occur in NE England and at the southern edge of the Moray Firth Basin in Scotland. From an examination of cliff and quarry exposures in Britain, and of drill cores from southern North Sea gas wells, it is now believed that the bulk of the Weissliegend sandstones (and their equivalents) were originally deposited as aeolian dunes. These dune sands, however, were later modified by a widespread event, the Zechstein transgression, which caused their partial homogenisation, the creation of large-scale soft-sediment deformation structures, and the local and minor reworking of some of the dune flanks. The preferred mechanism of deformation is interpreted as: (1) entrapment of large pockets of air within the bodies of the dunes by flanking and overlying wetted dune sands; (2) venting of the air pockets when the rising internal air pressures overcame the weight of the hydrostatic head of water and the capillary (cohesive) strength of the overlying wetted sands; (3) the rapid replacement of air by water, which caused liquidisation of the original dune laminae; and (4) the associated collapse and final consolidation of the sands into a tigher packing configuration. Deformations seem to be more developed in former transverse dunes than in seif dunes. The reason may be that the relatively tightly packed low-angle accretion bedding common on the flanks of seif dunes is more resistant to deformation than the looser avalanche sands that form a major part of transverse dunes. Limited reworking of former dune sands was probably best developed on the steep lee slopes of transverse dunes and the steeper upper slopes of seif dunes. The lack of reddening of the Weissliegend sandstones-proper is attributed to a combination of their accumulation above the Rotliegend water table, to the rapidity of the Zechstein transgression, and to the anoxic state of the early Zechstein sea floor. The Weissliegend sands, unlike the underlying Rotliegend into which they grade, were thus never in a diagenetic environment that was conducive to reddening. Finally, it is recommended that the term Weissliegend be dropped in any formational sense. It should only be retained for the Weissliegend proper, and their equivalents, to denote a complex facies association dominated by (1) the uppermost Early Permian Rotliegend dune sands (now partly deformed) that lay above the water table just prior to the Zechstein transgression, together with (2) the minor erosional marine products caused by that transgression. The latter, sensu stricto, are Zechstein sandstones of earliest Late Permian age.

Glennie, K. W.; Buller, A. T.

1983-05-01

254

The correlation between white-matter microstructure and the complexity of spontaneous brain activity: a difussion tensor imaging-MEG study.  

PubMed

The advent of new signal processing methods, such as non-linear analysis techniques, represents a new perspective which adds further value to brain signals' analysis. Particularly, Lempel-Ziv's Complexity (LZC) has proven to be useful in exploring the complexity of the brain electromagnetic activity. However, an important problem is the lack of knowledge about the physiological determinants of these measures. Although a correlation between complexity and connectivity has been proposed, this hypothesis was never tested in vivo. Thus, the correlation between the microstructure of the anatomic connectivity and the functional complexity of the brain needs to be inspected. In this study we analyzed the correlation between LZC and fractional anisotropy (FA), a scalar quantity derived from diffusion tensors that is particularly useful as an estimate of the functional integrity of myelinated axonal fibers, in a group of sixteen healthy adults (all female, mean age 65.56±6.06 years, intervals 58-82). Our results showed a positive correlation between FA and LZC scores in regions including clusters in the splenium of the corpus callosum, cingulum, parahipocampal regions and the sagittal stratum. This study supports the notion of a positive correlation between the functional complexity of the brain and the microstructure of its anatomical connectivity. Our investigation proved that a combination of neuroanatomical and neurophysiological techniques may shed some light on the underlying physiological determinants of brain's oscillations. PMID:21683794

Fernández, Alberto; Ríos-Lago, Marcos; Abásolo, Daniel; Hornero, Roberto; Alvarez-Linera, Juan; Paul, Nuria; Maestú, Fernando; Ortiz, Tomás

2011-08-15

255

Rethinking White Resistance: Exploring the Discursive Practices and Psychical Negotiations of "Whiteness" in Feminist, Anti-Racist Education  

ERIC Educational Resources Information Center

This article explores how under-theorized representations of whiteness in pedagogical literatures have informed simplistic ideas about white resistance among students. It is argued that the performance and practice of discourses of whiteness in pedagogical contexts, and the subjective, psychical and emotional complexities of engaging with…

Ringrose, Jessica

2007-01-01

256

Ruthenium metalation of proteins: the X-ray structure of the complex formed between NAMI-A and hen egg white lysozyme.  

PubMed

A crystallographic study of the adduct formed between hen egg white lysozyme (HEWL) and NAMI-A, an established ruthenium(III) anticancer agent in clinical trials, is presented here. The X-ray structure reveals that NAMI-A coordinates the protein, as a naked ruthenium ion, at two distinct sites (namely Asp101 or Asp119) after releasing all its original ligands (DMSO, imidazole and Cl(-)). Structural data of the HEWL/NAMI-A adduct are compared with those previously obtained for the HEWL adduct of AziRu, a NAMI-A analogue bearing a pyridine in place of imidazole. The present results further support the view that NAMI-A exerts its biological effects acting as a classical "prodrug" first undergoing activation and then causing extensive metalation of relevant protein targets. It is also proposed that the original Ru-ligands, although absent in the final adduct, play a major role in directing the ruthenium center to its ultimate anchoring site on the protein surface. PMID:24553967

Messori, Luigi; Merlino, Antonello

2014-04-28

257

The White Nile sedimentary system  

NASA Astrophysics Data System (ADS)

The Nile River flows for ~6700 km from south of the Equator to finally reach the Mediterranean Sea at northern subtropical latitudes (Woodward et al. 2007). This is the longest sedimentological laboratory on Earth, a unique setting in which we are investigating changes in sediment composition associated with diverse chemical and physical processes, including weathering and hydraulic sorting. The present study focuses on the southern branch of the Nile across 20° of latitude, from hyperhumid Burundi and Rwanda highlands in central Africa to Khartoum, the capital city of Sudan at the southern edge of the Sahara. Our study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than during stepwise transport, and shows that the transformation of parent rocks into quartzose sand may be completed in one sedimentary cycle (Garzanti et al. 2013a). Micas and heavy minerals, less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behaviour of chemical indices such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands (Garzanti et al. 2013b). Because sediment is efficiently trapped in East African Rift lakes, the composition of Nile sediments changes repeatedly northwards across Uganda. Downstream of both Lake Kyoga and Lake Albert, quartzose sands are progressively enriched in metamorphiclastic detritus supplied from tributaries draining amphibolite-facies basements. The evolution of White Nile sediments across South Sudan, a scarcely accessible region that suffered decades of civil war, was inferred from the available information (Shukri 1950), integrated by original petrographic, heavy-mineral and geochemical data (Padoan et al. 2011). Mineralogical and isotopic signatures of Bahr-el-Jebel and Sobat sediments, derived respectively from Archean gneisses of Uganda and Neoproterozoic basements of Ethiopia, become gradually homogenized and enriched in quartz, and remain finally unchanged down to Khartoum. This suggests massive sediment dumping in the Sudd and Machar Marshes, and explains why White Nile sediment contribution to the main Nile is negligible (Garzanti et al. 2006). REFERENCES Garzanti E., Andò S., Vezzoli G., Megid A.A.A., El Kammar A., 2006. Petrology of Nile River sands (Ethiopian and Sudan): sediment budgets and erosion patterns. EPSL 252:327-341. Garzanti E., Padoan M., Setti M., Peruta L., Najman Y., Villa I.M., 2013. Weathering geochemistry and Sr-Nd fingerprints of equatorial upper Nile and Congo muds. Geochem. Geophys. Geosyst. 14:292-316. Garzanti E., Padoan M., Andò S., Resentini A., Vezzoli G., Lustrino M., 2013. Weathering and relative durability of detrital minerals in equatorial climate: sand petrology and geochemistry in the East African Rift. J.Geol. 121:547-580. Padoan M., Garzanti E., Harlavan Y., Villa I.M., 2011. Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan). Geochim. Cosmochim. Acta 75:3627-3644. Shukri N.M., 1950. The mineralogy of some Nile sediments. Quart. J. Geol. Soc. London 105:511-534. Woodward J.C., Macklin M.G., Krom M.D., Williams M.A.J. 2007. The Nile: Evolution, quaternary river environments and material fluxes. In: Large Rivers, Avijit Gupta (Ed.), Wiley, 261-292.

Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Villa, Igor

2014-05-01

258

The Valuation of the Alberta Oil Sands  

Microsoft Academic Search

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

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

2008-01-01

259

Foundry Sand Facts for Civil Engineers.  

National Technical Information Service (NTIS)

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

2004-01-01

260

Pediatric neurodegenerative white matter processes: leukodystrophies and beyond  

Microsoft Academic Search

Pediatric neurodegenerative white matter processes are complex, numerous and result from a vast array of causes ranging from\\u000a white matter injury or inflammation to congenital metabolic disorders. When faced with a neurodegenerative white matter process\\u000a on neuroimaging, the first step for the radiologist is to determine whether the findings represent a congenital metabolic\\u000a leukodystrophy or one of various other white

Jonathan A. Phelan; Lisa H. Lowe; Charles M. Glasier

2008-01-01

261

Slow Sand Filtration: Influences of Selected Process Variables.  

National Technical Information Service (NTIS)

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

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

1985-01-01

262

Investigating the complex genetic architecture of ankle-brachial index, a measure of peripheral arterial disease, in non-Hispanic whites  

Microsoft Academic Search

BACKGROUND: Atherosclerotic peripheral arterial disease (PAD) affects 8–10 million people in the United States and is associated with a marked impairment in quality of life and an increased risk of cardiovascular events. Noninvasive assessment of PAD is performed by measuring the ankle-brachial index (ABI). Complex traits, such as ABI, are influenced by a large array of genetic and environmental factors

Sharon LR Kardia; M Todd Greene; Eric Boerwinkle; Stephen T Turner; Iftikhar J Kullo

2008-01-01

263

Australian Red Dune Sand: A Potential Martian Regolith Analog  

NASA Technical Reports Server (NTRS)

To demonstrate the potential scientific and technical merits of in situ microscopy on Mars, we analyzed a possible Martian regolith analog - an acolian red dune sand from the central Australian desert (near Mt. Olga). This sand was chosen for its ubiquitous red coating and the desert environment in which is it found. Grains of this sand were analyzed using a variety of microanalytical techniques. A database of detailed studies of such terrestrial analogs would assist the study of geological and astrobiological specimens in future missions to Mars. Potential instrument concepts for in situ deployment on Mars include local electrode atom probe nanoanalysis (LEAP), vertical scanning white light interferometry (VSWLI), scanning electron microscopies, energy dispersive x-ray microanalysis (EDX), atomic force microscopy (AFM) and X-ray diffraction (XRD). While in situ deployment of these techniques is many years away, ground-based studies using these analytical techniques extend our understanding of the data obtained from instruments to be flown in the near future.

Kuhlman, K. R.; Marshall, J.; Evans, N. D.; Luttge, A.

2001-01-01

264

Lithological discrimination and correlation in oil sands using rock magnetic properties  

SciTech Connect

The Lower Cretaceous McMurray Formation, which contains most of the bitumen reserves of the Athabasca oil sands, comprises uncemented quartz sands with siltstone, shale, and local ironstones. The sequential fluvial, estuarine, and marine depositional environments of the McMurray drainage basin have resulted in the complex juxtaposition of differing lithofacies. Horizontal continuity of lithofacies is limited. Sand body geometries are many and varied. Prediction of sand body geometry has important economic applications; a strong positive correlation exists between sand facies and oil grade. An investigation of the magnetic property variations in specimens from five closely adjacent boreholes within the McMurray Formation has shown that it is possible to: (1) document objective magnetic property parameters to differentiate distinct lithological units; (2) use these same magnetic parameters to establish between borehole lithostratigraphic correlations; and (3) to show that the magnitude of some magnetic parameters bears a direct relationship to the oil content of a lithology.

Morris, W.A. (McMaster Univ., Hamilton, Ontario (Canada))

1991-03-01

265

Proppant selection for fracturing and sand control  

SciTech Connect

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

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

1995-01-01

266

A study of infiltration on three sand capillary barriers  

Microsoft Academic Search

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

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

2004-01-01

267

Update on federal tight sands incentive policies  

SciTech Connect

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

Buch, L.

1980-11-01

268

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

269

Thermal recovery from tar sands  

SciTech Connect

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

Carrigy, M.A.

1983-12-01

270

Documentation of Recent Surface Winds on Martian Sand Dunes  

NASA Astrophysics Data System (ADS)

Images from the High Resolution Imaging Science Experiment (HiRISE) are of sufficient resolution to record wind ripple patterns on the surfaces of sand dunes present across the surface of Mars. We are in the early stages of an investigation to map the ripple orientations preserved on Martian sand dunes, in order to evaluate the recent wind flow over the dunes, and compare that wind flow pattern to the winds documented over terrestrial sand dunes. HiRISE image ESP_025645_1455 covers a sand dune field on the floor of a 20-km-diameter unnamed impact crater in the Terra Cimmeria region of the southern highlands, east of the Hellas impact basin. This image is centered at 34.23 S latitude, 138.437 E longitude with 25 cm/pixel resolution, and was taken on Jan 25 of 2012 during northern spring (Ls = 57.4). Using ArcGIS, lines were drawn across three ripples perpendicular to the ripple crests, avoiding places where complex ripple patterns suggest more than one recent wind direction. The length of the lines provides a measure of ripple wavelength, and the line orientation gives azimuth (with a 180 degree absolute ambiguity). The barchan-like shape of some dunes, including occasional slip faces, suggest sand driving winds were from the southwest, although dune asymmetries indicate the wind regime likely was much more complex than a unimodal wind. Measurements of ripple orientations are being collected from dune locations across the planet, which should provide new constraints for the modeling of recent Martian winds. This work was supported by NASA MDAP grant NNX12AJ38G.

Zimbelman, J. R.; Johnson, M. B.

2013-12-01

271

A comparison of culture-dependent and culture-independent techniques used to characterize bacterial communities on healthy and white plague-diseased corals of the Montastraea annularis species complex  

NASA Astrophysics Data System (ADS)

Diseases of hermatypic corals pose a global threat to coral reefs, and investigations of bacterial communities associated with healthy corals and those exhibiting signs of disease are necessary for proper diagnosis. One disease, commonly called white plague (WP), is characterized by acute tissue loss. This investigation compared the bacterial communities associated with healthy coral tissue ( N = 15), apparently healthy tissue on WP-diseased colonies ( N = 15), and WP-diseased tissues ( N = 15) from Montastraea annularis (species complex) colonies inhabiting a Bahamian reef. Aliquots of sediment ( N = 15) and water ( N = 15) were also obtained from the proximity of each coral colony sampled. Samples for culture-dependent analyses were inoculated onto one-half strength Marine Agar (½ MA) and Thiosulfate Citrate Bile Salts Sucrose Agar to quantify the culturable communities. Length heterogeneity PCR (LH-PCR) of the 16S rRNA gene characterized the bacterial operational taxonomic units (OTU) associated with lesions on corals exhibiting signs of a white plague-like disease as well as apparently healthy tissue from diseased and non-diseased conspecifics. Analysis of Similarity was conducted on the LH-PCR fingerprints, which indicated no significant difference in the composition of bacterial communities associated with apparently healthy and diseased corals. Comparisons of the 16S rRNA gene amplicons from cultured bacterial colonies (½ MA; N = 21) with all amplicons obtained from the whole coral-associated bacterial community indicated ?39 % of coral-associated bacterial taxa could be cultured. Amplicons from these bacterial cultures matched amplicons from the whole coral-associated bacterial community that, when combined, accounted for >70 % total bacterial abundance. An OTU with the same amplicon length as Aurantimonas coralicida (313.1 bp), the reported etiological agent of WPII, was detected in relatively low abundance (<0.1 %) on all tissue types. These findings suggest a coral disease resembling WP may result from multiple etiologies.

Cook, G. M.; Rothenberger, J. P.; Sikaroodi, M.; Gillevet, P. M.; Peters, E. C.; Jonas, R. B.

2013-06-01

272

[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

273

Mutations in MITF and PAX3 cause "splashed white" and other white spotting phenotypes in horses.  

PubMed

During fetal development neural-crest-derived melanoblasts migrate across the entire body surface and differentiate into melanocytes, the pigment-producing cells. Alterations in this precisely regulated process can lead to white spotting patterns. White spotting patterns in horses are a complex trait with a large phenotypic variance ranging from minimal white markings up to completely white horses. The "splashed white" pattern is primarily characterized by an extremely large blaze, often accompanied by extended white markings at the distal limbs and blue eyes. Some, but not all, splashed white horses are deaf. We analyzed a Quarter Horse family segregating for the splashed white coat color. Genome-wide linkage analysis in 31 horses gave a positive LOD score of 1.6 in a region on chromosome 6 containing the PAX3 gene. However, the linkage data were not in agreement with a monogenic inheritance of a single fully penetrant mutation. We sequenced the PAX3 gene and identified a missense mutation in some, but not all, splashed white Quarter Horses. Genome-wide association analysis indicated a potential second signal near MITF. We therefore sequenced the MITF gene and found a 10 bp insertion in the melanocyte-specific promoter. The MITF promoter variant was present in some splashed white Quarter Horses from the studied family, but also in splashed white horses from other horse breeds. Finally, we identified two additional non-synonymous mutations in the MITF gene in unrelated horses with white spotting phenotypes. Thus, several independent mutations in MITF and PAX3 together with known variants in the EDNRB and KIT genes explain a large proportion of horses with the more extreme white spotting phenotypes. PMID:22511888

Hauswirth, Regula; Haase, Bianca; Blatter, Marlis; Brooks, Samantha A; Burger, Dominik; Drögemüller, Cord; Gerber, Vincent; Henke, Diana; Janda, Jozef; Jude, Rony; Magdesian, K Gary; Matthews, Jacqueline M; Poncet, Pierre-André; Svansson, Vilhjálmur; Tozaki, Teruaki; Wilkinson-White, Lorna; Penedo, M Cecilia T; Rieder, Stefan; Leeb, Tosso

2012-01-01

274

Mutations in MITF and PAX3 Cause "Splashed White" and Other White Spotting Phenotypes in Horses  

PubMed Central

During fetal development neural-crest-derived melanoblasts migrate across the entire body surface and differentiate into melanocytes, the pigment-producing cells. Alterations in this precisely regulated process can lead to white spotting patterns. White spotting patterns in horses are a complex trait with a large phenotypic variance ranging from minimal white markings up to completely white horses. The “splashed white” pattern is primarily characterized by an extremely large blaze, often accompanied by extended white markings at the distal limbs and blue eyes. Some, but not all, splashed white horses are deaf. We analyzed a Quarter Horse family segregating for the splashed white coat color. Genome-wide linkage analysis in 31 horses gave a positive LOD score of 1.6 in a region on chromosome 6 containing the PAX3 gene. However, the linkage data were not in agreement with a monogenic inheritance of a single fully penetrant mutation. We sequenced the PAX3 gene and identified a missense mutation in some, but not all, splashed white Quarter Horses. Genome-wide association analysis indicated a potential second signal near MITF. We therefore sequenced the MITF gene and found a 10 bp insertion in the melanocyte-specific promoter. The MITF promoter variant was present in some splashed white Quarter Horses from the studied family, but also in splashed white horses from other horse breeds. Finally, we identified two additional non-synonymous mutations in the MITF gene in unrelated horses with white spotting phenotypes. Thus, several independent mutations in MITF and PAX3 together with known variants in the EDNRB and KIT genes explain a large proportion of horses with the more extreme white spotting phenotypes.

Blatter, Marlis; Brooks, Samantha A.; Burger, Dominik; Drogemuller, Cord; Gerber, Vincent; Henke, Diana; Janda, Jozef; Jude, Rony; Magdesian, K. Gary; Matthews, Jacqueline M.; Poncet, Pierre-Andre; Svansson, Vilhjalmur; Tozaki, Teruaki; Wilkinson-White, Lorna; Penedo, M. Cecilia T.; Rieder, Stefan; Leeb, Tosso

2012-01-01

275

Petrology of Nile River sands (Ethiopia and Sudan): Sediment budgets and erosion patterns  

Microsoft Academic Search

Detrital modes of modern Nile sands, together with estimates of sediment volumes trapped in Sudanese reservoirs, allow us to calculate sediment loads of major tributaries (Blue Nile, White Nile, Atbara) and erosion rates in the Nile catchment. A tridimensional array of high-resolution bulk-petrography and heavy-mineral data was obtained on both levee (suspended load) and bar (bedload) deposits, analysed separately for

Eduardo Garzanti; Sergio Andò; Giovanni Vezzoli; Ada Ali Abdel Megid; Ahmed El Kammar

2006-01-01

276

Direct laser sintering of a silica sand  

Microsoft Academic Search

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

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

2003-01-01

277

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

National Technical Information Service (NTIS)

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

1982-01-01

278

A branching process model for sand avalanches  

SciTech Connect

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

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

1993-07-01

279

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

280

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

281

Investigating Sand on the Coast of Oregon and Washington.  

ERIC Educational Resources Information Center

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

Komar, Paul D.

2002-01-01

282

White matter dementia  

PubMed Central

White matter dementia (WMD) is a syndrome introduced in 1988 to highlight the potential of cerebral white matter disorders to produce cognitive loss of sufficient severity to qualify as dementia. Neurologists have long understood that such a syndrome can occur, but the dominance of gray matter as the locus of higher function has strongly directed neurobehavioral inquiry to the cerebral cortex while white matter has received less attention. Contemporary neuroimaging has been crucial in enabling the recognition of white matter abnormalities in a host of disorders, and the correlation of these changes with cognitive performance. Comprising about half the brain, white matter is prominently or exclusively involved in well over 100 disorders, in each of which white matter dysfunction can potentially cause or contribute to dementia. Neuropsychological findings from ten categories of white matter disorder lead to a convergence of findings that document remarkable neurobehavioral commonality among the dementias produced. More recently, the syndrome of mild cognitive dysfunction (MCD) has been introduced to expand the concept of WMD by proposing a precursor syndrome related to early white matter neuropathology. WMD and MCD inform the understanding of how white matter contributes to normal and abnormal cognition, and the specific neuroanatomic focus of these syndromes may enhance the diagnosis and treatment of many disabling disorders that do not primarily implicate the cerebral cortex. Forming essential connections within widely distributed neural networks, white matter is critical for rapid and efficient information transfer that complements the information processing of gray matter. As neuroimaging continues to advance, further information on white matter structure can be expected, and behavioral neurology will play a central role in elucidating the functional significance of these emerging data. By emphasizing the contribution of myelinated systems to higher function, the study of white matter and cognition represents investigation of the basic neuroscience of human behavior.

2012-01-01

283

Adsorption of a dye on clay and sand. Use of cyclodextrins as solubility-enhancement agents.  

PubMed

Laboratory-scale studies were aimed at elucidating the physico-chemical aspects on the removal process of crystal violet (CV) from waters and solid substrates. The laponite clay (RD) and sand were chosen for the double aim at investigating them as CV adsorbents for water treatment and as substrates which mime the soil components. Sand is very effective in removing CV from waters. The cyclodextrins (CDs) were exploited as solubility-enhancement agents to remove CV from the solid substrates. They are powerful solvent media because they extract the CV from sand forming water-soluble CV/CD inclusion complexes and do not show affinity for sand. Optimum performance was shown by the modified CDs (i.e. hydroxypropyl-beta-cyclodextrin and methyl-beta-cyclodextrin). A linear correlation between the logarithm of the equilibrium constant for the CV/CD inclusion complexes formation (K(cpx)) and the maximum amount of CV extracted from sand in the columns experiments at a flow rate of 1.5 ml min(-1) was drawn. This relationship predicts that CDs with K(cpx)<180 M(-1) are not suitable for CV removal from sand. CDs failed to displace CV from RD because they generate the formation of RD clusters where CV remains entrapped. PMID:17644152

De Lisi, Rosario; Lazzara, Giuseppe; Milioto, Stefania; Muratore, Nicola

2007-11-01

284

Adding Value to Alberta's Oil Sands  

Microsoft Academic Search

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

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

2006-01-01

285

Separation of Bitumen from Bituminous Sands  

Microsoft Academic Search

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

K. A. Clark

1931-01-01

286

Syncrude-oil from Alberta's tar sands  

Microsoft Academic Search

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

1980-01-01

287

Future of heavy crude and tar sands  

Microsoft Academic Search

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

R. F. Meyer; C. T. Steele

1981-01-01

288

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

289

Sand Tray Group Counseling with Adolescents  

ERIC Educational Resources Information Center

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

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

2003-01-01

290

RADIUM REMOVAL USING SORPTION TO FILTER SAND  

EPA Science Inventory

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

291

Cracking the tight sands of Texas  

Microsoft Academic Search

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

Geddie

2009-01-01

292

GRI Program for Tight Gas Sands Research  

Microsoft Academic Search

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

Patrick OShea; William Murphy

1982-01-01

293

Update on federal tight sands incentive policies  

Microsoft Academic Search

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

Buch

1980-01-01

294

Why are ripples absent in coarse sands?  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

295

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

296

Use of Foundry Sands in Transportation Applications.  

National Technical Information Service (NTIS)

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

C. Vipulanandan S. Cho S. Wang

2005-01-01

297

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

USGS Publications Warehouse

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

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

1987-01-01

298

Inflammatory and genotoxic effects of sanding dust generated from nanoparticle-containing paints and lacquers.  

PubMed

Nanoparticles are increasingly used in paints and lacquers. Little is known of the toxicity of nanoparticles incorporated in complex matrices and released during different phases of the life cycle. DNA damaging activity and inflammogenicity of sanding dust sampled during standardised sanding of boards painted with paints with and without nanoparticles were determined 24 h after intratracheal instillation of a single dose of 54 ?g in mice. Dusts from nanoparticle-containing paints and lacquers did not generate pulmonary inflammation or oxidative stress. Sanding dust from both the nanoparticle-containing and the conventional lacquer and the outdoor acrylic-based reference paint increased the level of DNA strand breaks in bronchoalveolar fluid cells. In conclusion, addition of nanoparticles to paint or lacquers did not increase the potential of sanding dust for causing inflammation, oxidative stress or DNA damage, suggesting that the paint/lacquer matrix is more important as determinant of DNA damage than the nanomaterial. PMID:21995293

Saber, Anne Thoustrup; Koponen, Ismo Kalevi; Jensen, Keld Alstrup; Jacobsen, Nicklas Raun; Mikkelsen, Lone; Møller, Peter; Loft, Steffen; Vogel, Ulla; Wallin, Håkan

2012-11-01

299

Aeolian sand transport: a wind tunnel model  

NASA Astrophysics Data System (ADS)

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

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

2003-09-01

300

Solvent leaching of tar sands  

SciTech Connect

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

Oguztoreli, M.; Faroqu, S.M.

1983-11-01

301

Preserving inland drift sands in the Netherlands  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

302

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

303

Investigation of Re-Use Options for Used Traction Sand.  

National Technical Information Service (NTIS)

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

A. K. Pulley K. Baird

2010-01-01

304

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

SciTech Connect

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

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

1996-06-01

305

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

306

Acoustic detection of Immiscible Liquids in Sand  

SciTech Connect

Laboratory cross-well P-wave transmission at 90 kHz was measured in a 61 cm diameter by 76 cm tall water-saturated sand pack, before and after introducing a non-aqueous phase organic liquid (NAPL) (n-dodecane). In one experiment NAPL was introduced to form a lens trapped by a low permeability layer; a second experiment considered NAPL residual trapped behind the front of flowing NAPL. The NAPL caused significant changes in the travel time and amplitude of first arrivals, as well as the generation of diffracted waves arriving after the direct wave. The spatial variations in NAPL saturation obtained from excavation at the end of the experiment correlated well with the observed variations in the P-wave amplitudes and travel times. NAPL residual saturation changes from NAPL flow channels of 3 to 4% were detectable and the 40 to 80% NAPL saturation in the NAPL lens was clearly visible at acoustic frequencies. The results of these experiments demonstrate that small NAPL saturations may be more easily detected with amplitude rather than travel time data, but that the relationships between the amplitude changes and NAPL saturation maybe more complex than those for velocity.

Geller, Jil T.; Kowalsky, Michael B.; Seifert, Patricia K.; Nihei, Kurt T.

1999-03-01

307

Sailing to White Boat  

NASA Technical Reports Server (NTRS)

This is a composite red-green-blue image of the rock called White Boat. It is the first rock target that Spirit drove to after finishing a series of investigations on the rock Adirondack. White Boat stood out to scientists due to its light color and more tabular shape compared to the dark, rounded rocks that surround it.

2004-01-01

308

White Flight: Some Hypotheses.  

ERIC Educational Resources Information Center

The available literature on white flight, or, more properly, school resegregation -- the phenomenon of white withdrawal (total or partial) from desegregated schools -- is reviewed in this paper which also reports some new research in this area. The distinction is made between those schools located on the fringes of the inner city, which first…

Wegmann, Robert G.

309

White Teachers Talking Race  

ERIC Educational Resources Information Center

In light of the increasing racial diversity in American schools and the consistently homogenous teacher workforce in the United States, understanding the ways white teachers consider and attend to racial issues is of crucial importance to the educational landscape. This paper, based on a qualitative study, explores five white American…

Segall, Avner; Garrett, James

2013-01-01

310

White Collar Crime.  

National Technical Information Service (NTIS)

Probes the extent and effect of white collar crime in Oklahoma, its enormous social cost through erosion of social values and respect for authority. White collar criminals often have the means to obtain private attorneys, are the least likely to go to jai...

1994-01-01

311

Insecticide resistance in the sand fly, Phlebotomus papatasi from Khartoum State, Sudan  

PubMed Central

Background Phlebotomus papatasi the vector of cutaneous leishmaniasis (CL) is the most widely spread sand fly in Sudan. No data has previously been collected on insecticide susceptibility and/or resistance of this vector, and a first study to establish a baseline data is reported here. Methods Sand flies were collected from Surogia village, (Khartoum State), Rahad Game Reserve (eastern Sudan) and White Nile area (Central Sudan) using light traps. Sand flies were reared in the Tropical Medicine Research Institute laboratory. The insecticide susceptibility status of first progeny (F1) of P. papatasi of each population was tested using WHO insecticide kits. Also, P. papatasi specimens from Surogia village and Rahad Game Reserve were assayed for activities of enzyme systems involved in insecticide resistance (acetylcholinesterase (AChE), non-specific carboxylesterases (EST), glutathione-S-transferases (GSTs) and cytochrome p450 monooxygenases (Cyt p450). Results Populations of P. papatasi from White Nile and Rahad Game Reserve were sensitive to dichlorodiphenyltrichloroethane (DDT), permethrin, malathion, and propoxur. However, the P. papatasi population from Surogia village was sensitive to DDT and permethrin but highly resistant to malathion and propoxur. Furthermore, P. papatasi of Surogia village had significantly higher insecticide detoxification enzyme activity than of those of Rahad Game Reserve. The sand fly population in Surogia displayed high AChE activity and only three specimens had elevated levels for EST and GST. Conclusions The study provided evidence for malathion and propoxur resistance in the sand fly population of Surogia village, which probably resulted from anti-malarial control activities carried out in the area during the past 50 years.

2012-01-01

312

Growth of Loblolly Pine and White Pine after Enrichment by Nutrient Loading  

Microsoft Academic Search

Low nutrient availability often constrains the growth of young trees following planting to fields or forests. Nutrient loading of young tree seedlings increases their growth in outplanting. Loblolly pine (Pinus taeda L.) and white pine (Pinus strobus L.) were grown for one year on nutrient-loading regimes that varied from 13 to 410 mg N L in sand culture. Other nutrients

Allen V. Barker

2010-01-01

313

Critical state of sand matrix soils.  

PubMed

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

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

2014-01-01

314

Critical State of Sand Matrix Soils  

PubMed Central

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

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

2014-01-01

315

Fatal outcome of a sand aspiration.  

PubMed

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

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

2008-11-01

316

Indications and potential sources of change in sand transport in the Brazos River, Texas  

USGS Publications Warehouse

Changes in the capacity of the Brazos River to transport sand can be identified within the context of Lane?s relation through changes in channel geometry, changes in the characteristics of suspended loads, and changes in discharge. The Brazos River channel has been undergoing continual adjustment since the 1940s. For a discharge of 5,000 cubic feet per second, the water-surface altitude has decreased 2 to 4 feet at the Hempstead and Richmond streamflow-gaging stations between 1940 and 1995. The characteristics of suspended-sediment samples at the Richmond streamflow-gaging station have changed between the periods 1969?81 and 1982?95. The amount of sand-size sediment transported in suspension has decreased. The distribution of both daily and annual-peak discharges has changed. However, the computed annual loads of suspended sand indicate no statistically significant change in the median annual load. The transport of sand in the Brazos River depends on a complex set of factors, most of which are continually changing. Potential sources of change in sand transport in the Brazos River include the effects of reservoir construction, changes in land use, and instream sand and gravel mining. Extensive reservoir construction in the Brazos River Basin has reduced sand transport by trapping sediment and by reducing the magnitude of peak discharges. However, reductions in sand transport associated with reservoir construction apparently are compensated for by increases associated with tributary sediment inflow and localized bank erosion. The total area of harvested acres of non-hay crops in the lower Brazos River Basin during 1924?92 decreased more than 75 percent from about 32 percent to about 8 percent of the total area. Correspondingly, erosion potential has decreased substantially. Several sand and gravel mining sites are located on the Brazos River between Hempstead and Rosharon. The quantity of sediment extracted by instream sand and gravel mining operations could represent from 11 to 25 percent of the total sand transported by the Brazos River. The effects of mining on sand transport could not be quantified.

Dunn, David D.; Raines, Timothy H.

2001-01-01

317

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

318

Handling Whiting Aboard Fishing Vessels.  

National Technical Information Service (NTIS)

The same fundamental principles for handling fresh fish in general aboard fishing vessels apply to whiting. Following a comprehensive study of the whiting fishing industry for the purpose of improving the quality of landed whiting, recommendations were ma...

J. J. Licciardello

1980-01-01

319

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

PubMed Central

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

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

2011-01-01

320

Modification of hypoeutectic low alloy white cast irons  

Microsoft Academic Search

In order to modify the continuous network of eutectic cementite normally found in low alloy white cast irons into a dispersive distribution, strategies of controlling the morphology of eutectic cementite by additives are discussed. Qualitative arguments are presented and applied to the development of a complex modifier REAINTi. With the addition of this modifier to low carbon white cast irons

Ma Qian; Wang Chaochang; Shoji Harada

1996-01-01

321

National Security Challenges: Insights from Social, Neurobiological, and Complexity Sciences. Topical Strategic Multi-Layer Assessment (SMA) and U.S. Army ERDC Multi-Agency/Multi-Disciplinary White Papers in Support of National Security Challenges.  

National Technical Information Service (NTIS)

This White Volume assesses U.S. long term national security challenges, employing a global perspective that accounts for the changing political, economic, social, and psychological profiles of populations, and the rapid changes they experience in a global...

2012-01-01

322

Developments in tar sands in 1984  

SciTech Connect

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

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

1985-10-01

323

Developments in tar sands in 1984  

SciTech Connect

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

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

1985-10-01

324

VideoLab: Swimming in Sand  

NSDL National Science Digital Library

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

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

2009-07-17

325

Syncrude-oil from Alberta's tar sands  

SciTech Connect

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

Lund, C.N.

1980-12-01

326

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

327

Sound-producing dune and beach sands  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

328

Symposium on School Desegregation and White Flight.  

ERIC Educational Resources Information Center

Five papers intended to serve as an introduction to a complex and rapidly growing body of research are included in this volume. These papers represent the work of scholars who have studied the problem of white flight long before the current controversy over urban desegregation plans made it a national issue. Starting from very different…

Orfield, Gary, Ed.

329

Inside The White House Situation Room.  

National Technical Information Service (NTIS)

Go to the southwest gate of the White House complex, present the guard with identification, and state your business. If you are on the appointment list, an escort will be called. Walk up West Executive Avenue and turn tight into the West Basement entrance...

C. O'Leary J. Montgomery M. Donley

1997-01-01

330

Canyon dissolution of sand, slag, and crucible residues  

SciTech Connect

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

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

1997-12-01

331

Batch and column studies of adsorption of Li, Ni and Br by a reference sand for contaminant transport experiments  

SciTech Connect

A processed quartz sand (Wedron 510), mined from the St. Peter sandstone, has been characterized by a variety of chemical and physical methods for use as a reference porous media in transport model validation experiments. Wedron 510 sand was used in an intermediate-scale experiment involving migration of Ni, Li and Br through a 6-m high x 3-m diameter caisson. Ni and Li adsorption/desorption, and Li/Ni site-competition experiments yielded information on the importance of the trace mineral phases to adsorption of Li and Ni by the sand. The presence of an iron hydroxide coating similar to goethite on the sand grains is suggested by visual observation and leaching experiments. Kaolinite was identified by SEM and XRD as a significant trace mineral phase in the sand and occurs as small particles coating the sand grains. Quartz, the predominant constituent of the sand by weight, does not appear to contribute significantly to the adsorption properties of the sand. Qualitatively, the adsorption properties of the sand can be adequately modeled as a two-mineral system (goethite and kaolinite). The studies described in this report should provide a basis for understanding transport of Ni, Li and Br through porous media similar to the reference sand. Techniques were developed for obtaining parameter values for surface complexation and kinetic adsorption models for the sand and its mineral components. These constants can be used directly in coupled hydrogeochemical transport codes. The techniques should be useful for characterization of other natural materials and elements in high-level nuclear waste in support of coupled hydrogeochemical transport calculations for Yucca Mountain.

Seigel, M.D. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Ward, D.B.; Bryan, C.R. [Univ. of New Mexico, Albuquerque, NM (United States)] [and others] [Univ. of New Mexico, Albuquerque, NM (United States); and others

1995-09-01

332

Cardioprotection with white wine.  

PubMed

The cardioprotective effects of red wine have been attributed to several polyphenolic antioxidants including resveratrol and proanthocyanidins. The goal of the present study was to determine whether white wines could also provide cardioprotection. Three different white wines (white wine #1, #2 and #3) were chosen for this study. Ethanol-free extracts of the wines were prepared by vacuum evaporation. Rats weighing approximately 200 g were given either 50 mg/kg or 100 mg/kg of each wine extract for 3 weeks. The rats were anesthetized and sacrificed and their hearts were excised for the preparation of isolated working rat heart. All hearts were subjected to 30 min of global ischemia followed by 2 h of reperfusion. Cardiac function including heart rate, left ventricular developed pressure (LVDP), maximum first derivative of developed pressure (LVdp/dtmax), left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEP), aortic flow (AF) and coronary flow (CF) were continuously monitored and myocardial infarct size was measured at the end of the experiments. The results of our study demonstrated that among the three different white wines, only white wine #2 conferred cardioprotection as evidenced by improved postischemic ventricular recovery compared with controls. The same white wine at a dose of 50 mg/kg also showed improvement in postischemic contractile recovery but the differences compared with controls were not significant. The amount of malondialdehyde production from these hearts was lower than that found in control hearts, indicating reduced formation of reactive oxygen species in white wine #2-treated rats. In vitro studies using a chemiluminescence technique revealed that white wine #2 scavenged both superoxide anions and hydroxyl radicals. The results of our study demonstrate that white wine #2 provided cardioprotection and the cardioprotective effect of the wine can be attributed, at least in part, to its ability to function as an in vivo antioxidant. PMID:12073762

Cui, J; Tosaki, A; Bertelli, A A E; Bertelli, A; Maulik, N; Das, D K

2002-01-01

333

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

334

White Earth Limb  

NASA Technical Reports Server (NTRS)

Edward H. White II, pilot of the Gemini 4 spacecraft, floats in the zero gravity of space with an earth limb backdrop. The extravehicular activity was performed during the third revolution of the Gemini 4 spacecraft and represents the first time an American has stepped outside the confines of his spacecraft. White is attached to the spacecraft by a 25-ft. umbilical line and a 23-ft. tether line, both wrapped in gold tape to form one cord. In his right hand White carries a Hand-Held Self-Maneuvering Unit (HHSMU). The visor of his helmet is gold plated to protect him from the unfiltered rays of the sun.

1965-01-01

335

Fracturing made development of tight gas sand economical  

SciTech Connect

Operators in Pecos Slope field in eastern New Mexico tried several stimulation techniques to boost production from its low pressure, low permeability pay zone, but complex geology made direct well-to-well comparison difficult. This article answers some of the questions that arose with a detailed study of lab work and data from over 125 wells. Benefits and limitations of various methods used are discussed, including fluid type, pump rate, sand concentration and treatment volumes. Practical recommendations for obtaining longterm production from this and similar fields are provided.

Nall, A.; Boney, C.; Campbell, P.

1983-07-01

336

Fracturing made development of tight gas sand economical  

SciTech Connect

Operators in Pecos Slope field in E. New Mexico tried several stimulation techniques to boost production from its low pressure, low permeability pay zone, but complex geology made direct well-to-well comparison difficult. This study answers some of the questions that arose with a detailed study of lab work and data from over 125 wells. Benefits and limitations of various methods used are discussed, including fluid type, pump rate, sand concentration, and treatment volumes. Practical recommendations for obtaining long-term production from this and similar fields are provided.

Nall, A.; Campbell, P.; Boney, C.

1983-07-01

337

Object technology: A white paper  

SciTech Connect

Object-Oriented Technology (OOT), although not a new paradigm, has recently been prominently featured in the trade press and even general business publications. Indeed, the promises of object technology are alluring: the ability to handle complex design and engineering information through the full manufacturing production life cycle or to manipulate multimedia information, and the ability to improve programmer productivity in creating and maintaining high quality software. Groups at a number of the DOE facilities have been exploring the use of object technology for engineering, business, and other applications. In this white paper, the technology is explored thoroughly and compared with previous means of developing software and storing databases of information. Several specific projects within the DOE Complex are described, and the state of the commercial marketplace is indicated.

Jordan, S.R.; Arrowood, L.F.; Cain, W.D.; Stephens, W.M.; Vickers, B.D.

1992-05-11

338

On the nature of Athabasca Oil Sands.  

PubMed

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

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

2005-06-30

339

Western Gas Sands Project Status Report.  

National Technical Information Service (NTIS)

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

C. H. Atkinson

1978-01-01

340

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

341

Tight Gas Sands Log Interpretation: Problem Study.  

National Technical Information Service (NTIS)

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

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

1983-01-01

342

Recent activity in U. S. tar sand  

SciTech Connect

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

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

1980-01-01

343

Survey and Study on Sand and Dirt.  

National Technical Information Service (NTIS)

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

E. Kuletz H. C. Schafer

1971-01-01

344

The analysis of electrification in windblown sand  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

345

Oil sands: resource, recovery, and industry  

SciTech Connect

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

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

1980-07-01

346

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

347

Guide to preparing SAND reports. Revision.  

National Technical Information Service (NTIS)

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

1995-01-01

348

Guide to preparing SAND reports. Revised.  

National Technical Information Service (NTIS)

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

T. K. Locke

1996-01-01

349

Evaluation of Sand Resources, Atlantic Offshore, Delaware.  

National Technical Information Service (NTIS)

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

K. K. McKenna K. W. Ramsey

2002-01-01

350

Sand Dunes: A Phenomenon Of Wind  

NSDL National Science Digital Library

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

2010-06-29

351

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

352

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

353

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

354

White-Light Optical Information Processing and Holography.  

National Technical Information Service (NTIS)

The first phase of our research program on white-light optical information processing and holography has been completed. In this period, we have synthesized an optical information processing system, which permits complex spatial filtering with a broad ban...

F. T. S. Yu

1982-01-01

355

Electrosynthesis of nickel phosphides on the basis of white phosphorus  

Microsoft Academic Search

Reduction of white phosphorus in the coordination sphere of the electrochemically generated nickel(0) complexes with ?-donor ligands was shown to be possible and accompanied by the transformation of P4 into the nickel phosphides.

Yu. H Budnikova; D. I Tazeev; B. A Trofimov; O. G Sinyashin

2004-01-01

356

Modeling surficial sand and gravel deposits  

USGS Publications Warehouse

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

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

1994-01-01

357

Dynamics of a Projectile Penetrating Sand  

Microsoft Academic Search

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

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

1957-01-01

358

Laboratory evaluation of selected tar sand asphalts  

SciTech Connect

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

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

1980-12-01

359

Fatal outcome of a sand aspiration  

Microsoft Academic Search

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

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

2008-01-01

360

Geometry and dynamics of deterministic sand piles  

SciTech Connect

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

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

1990-09-15

361

GRI program for tight gas sands research  

SciTech Connect

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

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

1982-01-01

362

Humate in coastal sands of northwest Florida  

Microsoft Academic Search

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

V. E. Swanson; J. G. Palacas

1965-01-01

363

Ryan White Program  

MedlinePLUS

... the larger fiscal environment and health system. Recent economic conditions have meant increased demands on Ryan White ... community-based services, mental health services, and case management, among others. ? Return to text Grandfathered EMAs are ...

364

Carpenter in White Room  

NASA Technical Reports Server (NTRS)

Inside Hangar S at the White Room Facility at Cape Canaveral, Florida, Mercury astronaut M. Scott Carpenter examines the honeycomb protective material on the main pressure bulkhead (heat shield) of his Mercury capsule nicknamed 'Aurora 7.'

1962-01-01

365

White Blood Cell Disorders  

MedlinePLUS

... the five major types of white blood cells: Neutrophils Lymphocytes Monocytes Eosinophils Basophils Normally, people produce about ... types together or all five types. Disorders of neutrophils and disorders of lymphocytes are the most common. ...

366

GENERALIZED WHITE NOISE OPERATOR FIELDS AND QUANTUM WHITE NOISE DERIVATIVES  

Microsoft Academic Search

Regarding a Fock space operator as a function of quantum white noise = ( at;a t ; t2 T ), we introduce its quantum white noise derivatives (qwn- derivatives) as a kind of functional derivatives with respect to at and a t . We prove that every white noise operator is dierentiable and the qwn-derivatives form a gen- eralized white

Un Cig Ji; Nobuaki Obata

367

When White Dwarfs Collide  

NASA Astrophysics Data System (ADS)

3D models of white dwarf collisions are used to assess the likelihood of double-degenerate mergers as progenitors for Type Ia supernovae (henceforth SNIa) and to identify observational signatures of double-degenerate collisions. Observations of individual SNIa, SNIa rates in different galaxy types, and double white dwarf binary systems suggest that mergers or collisions between two white dwarfs play a role in the overall SNIa population. Given the possibility of two progenitor systems (single-degenerate and double-degenerate), the sample of SNIa used in cosmological calcula- tions needs to be carefully examined. To improve calculations of cosmological parameters, the development of calibrated diagnostics for double-degenerate progenitor SNIa is essential. Head-on white dwarf collision simulations are used to provide an upper limit on the 56Ni production in white dwarf collisions. In chapter II, I explore zero impact parameter collisions of white dwarfs using the Eulerian grid code FLASH. The initial 1D white dwarf profiles are created assuming hydrostatic equilibrium and a uniform composition of 50% 12C and 50% 16O. The masses range from 0.64 to 0.81 solar masses and have an isothermal temperature of 107 K. I map these 1D models onto a 3D grid, where the dimensions of the grid are each eight times the white dwarf radius, and the dwarfs are initially placed four white dwarf radii apart (center to center). To provide insight into a larger range of physical possibilities, I also model non-zero impact parameter white dwarf collisions (Chapter III). Although head-on white dwarf collisions provide an upper limit on 56Ni production, non-zero impact parameter collisions provide insight into a wider range of physical scenarios. The initial conditions (box size, initial separation, composition, and initial temperature) are identical to those used for the head-on collisions (Chapter II) for the same range of masses. For each mass pair- ing, collision simulations are carried out at impact parameters b=1 and b=2 (grazing). Finally, I will address future work to be performed (Chapter IV).

Hawley, Wendy Phyllis

368

Interaction forces in bitumen extraction from oil sands  

Microsoft Academic Search

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

Jianjun Liu; Zhenghe Xu; Jacob Masliyah

2005-01-01

369

Treatment Efficiencies of Slow Sand Filtration for Landscape Water  

Microsoft Academic Search

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

Cui Li; Yifan Wu; Liangbo Zhang; Wen Liu

2010-01-01

370

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

371

Methanogenic potential of tailings samples from oil sands extraction plants  

Microsoft Academic Search

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

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

2002-01-01

372

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

Microsoft Academic Search

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

Mark Sherrington

2005-01-01

373

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

374

Optical Dating of Tsunami-Laid Sands  

NASA Astrophysics Data System (ADS)

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

Huntley, David J.; Clague, John J.

1996-09-01

375

Composition of the Sand Fly Fauna in Khash County, Southeast Iran  

PubMed Central

Sand flies (Diptera: Psychodidae: Phlebotominae) are the biological vectors of leishmaniasis all around the world. In 1997, sand flies were collected in 14 cities and villages of Khash County in southeastern Iran, using 848 sticky traps (castor oil-coated white papers 20 × 30 cm). In this study, a total of 4673 sand flies, with 25.23% females and 74.77% males, were collected and identified to species mainly from mountainous areas. The 21 species of sand flies belonged to the genus Phlebotomus (nine species) and the genus Sergentomyia (12 species). The following 14 species were reported for the first time in Khash County: P. papatasi, P. bergeroti, P. eleanorae, P. halepensis, P. major, P. mesghali, S. hodgsoni, S. mervynae, S. dreyfussi, S. iranica, S. theodori, S. africana, S. clydei, and S. christophersi. The composition of species in Khash County is similar to other parts of Iran. However, the dominance of P. kazeruni in Khash County may suggest that this species should be considered as a potential vector in the region of Khash.

Kassiri, Hamid; Javadian, Ezatoeddin

2012-01-01

376

The effect of nitrogen on root growth and nutrient uptake of young tea plants ( Camellia sinensis L.) grown in sand culture  

Microsoft Academic Search

Root growth and nutrient uptake of a tea clone were studied in a sand culture experiment using ammonium sulphate, ammonium nitrate and urea each at 35, 70 and 105 ppm N. Results show that increasing N levels regardless of forms increased the proportion of white roots and decreased brown root weight.

G. S. Chamuah

1988-01-01

377

United states tar sands as a petroleum source  

Microsoft Academic Search

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

Ball

1967-01-01

378

Influence of Oil Saturation Upon Spectral Induced Polarization of Oil Bearing Sands  

EPA Science Inventory

The presence of oil in an unconsolidated granular porous material such as sand changes both the resistivity of the material and the value of the phase shift between the low-frequency current and the voltage. The resistivity and the phase angle can be written as a complex-valued r...

379

Repellent efficacy of a combination containing imidacloprid and permethrin against sand flies ( Phlebotomus papatasi ) in dogs  

Microsoft Academic Search

Infection in dogs and humans with the protozoan parasite Leishmania are widespread in tropical and subtropical countries around the globe. Sand flies of the order Phlebotomus in the Old World and Lutzomyia in the New World function as the vector of this disease. In dogs, skin lesions are the most prominent signs of canine leishmaniasis, besides other complex underlying manifestations.

N. Mencke; P. Volf; V. Volfova; D. Stanneck

2003-01-01

380

Depositional environments of Schuler Formation (Cotton Valley Sands), Upshur County, Texas  

Microsoft Academic Search

Exploration for tight gas (FERC Section 107) production from the Schuler Formation (Cotton Valley sands) has provided recent data for the recognition of the lower Schuler (Shongaloo member) shoreface facies and delineation of the upper Schuler (Dorcheat member) delta plain complex in Upshur County. Shoreface facies within the lower Schuler have a typical funnel-shaped log pattern (coarsening-upward clastic). In core,

Joe A. Kast

1983-01-01

381

The Geological Challenge for Development of Heavy Crude and Oil Sands of Western Canada  

Microsoft Academic Search

Many years of drilling has delineated the Heavy Crude and Oil Sands Deposits of Western Canada. Although the vast areal extent of these deposits is relatively well-known, an understanding of their depositional history is less clear. For the geologist, the challenge is not the discovery of new reserves, but rather the search for suitable recovery targets within the complex stratigraphy

Don McPhee; Michael J. Ranger

1998-01-01

382

Sorption and filtration of metals using iron-oxide-coated sand  

Microsoft Academic Search

Iron oxides are good adsorbents for uncomplexed metals, some metal-ligand complexes, and many metal oxyanions. However, the adsorbent properties of these oxides are not fully exploited in wastewater treatment operations because of difficulties associated with their separation from the aqueous phase. This paper describes experiments in which iron oxides were coated onto the surface of ordinary filter sand, and this

Mark M. Benjamin; Ronald S. Sletten; Robert P. Bailey; Thomas Bennett

1996-01-01

383

Cognitive Correlates of White Matter Growth and Stress Hormones in Female Squirrel Monkey Adults  

Microsoft Academic Search

Neurobiological studies of stress and cognitive aging seldom consider white matter despite indications that complex brain processes depend on networks and white matter interconnections. Frontal and temporal lobe white matter volumes increase throughout midlife adulthood in humans, and this aspect of aging is thought to enhance distributed brain functions. Here, we examine spatial learning and memory, neuroendocrine responses to psychological

David M. Lyons; Chou Yang; Stephan Eliez; Allan L. Reiss; Alan F. Schatzberg

2004-01-01

384

Sediment-starved sand ridges on a mixed carbonate\\/siliciclastic inner shelf off west-central Florida  

Microsoft Academic Search

High-resolution side-scan mosaics, sediment analyses, and physical process data have revealed that the mixed carbonate\\/siliciclastic, inner shelf of west-central Florida supports a highly complex field of active sand ridges mantled by a hierarchy of bedforms. The sand ridges, mostly oriented obliquely to the shoreline trend, extend from 2 km to over 25 km offshore. They show many similarities to their

S. E. Harrison; S. D. Locker; A. C. Hine; J. H. Edwards; D. F. Naar; D. C. Twichell; D. J. Mallinson

2003-01-01

385

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

National Technical Information Service (NTIS)

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

B. R. Phillips

1986-01-01

386

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

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

387

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

NASA Astrophysics Data System (ADS)

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

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

1987-05-01

388

Wind tunnel experimental investigation of sand velocity in aeolian sand transport  

NASA Astrophysics Data System (ADS)

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

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

2008-05-01

389

COMPLEX CONDUCTIVITY RESPONSE TO NANOMATERIALS IN A SAND MATRIX  

EPA Science Inventory

Nano-scale metallic particles are being used with increasing frequency in a variety of industrial, medical, and environmental remediation applcations. The fate and transport of such materials in the subsurface is not fully understood, neither is the impact of these materials on ...

390

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

Microsoft Academic Search

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

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

2011-01-01

391

White Dwarf Stars  

NASA Astrophysics Data System (ADS)

White dwarfs are the final stage for more than 95% of all stars. Their population statistics and properties contain a wealth of information about the history of star formation in our galaxy, the ages of stellar systems, and the relation between original mass at birth and that of the final remnant. They are also interesting individually as laboratories for physical conditions not easily reached in terrestrial labs: macroscopic manifestation of the Pauli principle, high densities and pressures, and extremely high magnetic fields. After a brief introduction with some historical milestones the observational status is reviewed: spectroscopic classification, determination of stellar parameters from spectroscopic and photometric observations, effective temperatures, surface gravities, radii, and masses. The next sections deal with the physics of the interior and evolution of white dwarfs, leading to the mass-radius relation and cooling times. Going back closer to the observations again, the physical processes in the outer layers are discussed: gravitational separation, diffusion, radiative levitation, accretion, and convective mixing. This leads to a review of our current understanding of the origin of spectral types and their interrelation. A final section gives brief introductions to topics at the center of current research: white dwarfs in open and globular clusters, debris disks, the origin of accreted metals in the atmospheres, magnetic fields and their origin, variable white dwarfs, and white dwarfs in binaries. This chapter was finished in February 2010 and reflects the status of knowledge at that time.

Koester, Detlev

392

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

393

Sand filter clogging by septic tank effluent.  

PubMed

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

Spycha?a, M; B?azejewski, R

2003-01-01

394

A study of morphology, provenance, and movement of desert sand seas in Africa, Asia, and Australia  

NASA Technical Reports Server (NTRS)

A description and classification of major types of sand seas on the basis of morphological pattern and lineation are discussed. The steps involved in analyzing the patterns of deposits on ERTS-1 imagery, where the visible forms are mostly dune complexes rather than individual dunes are outlined. After completion of thematic maps portraying the pattern and lineation of the sand bodies, data on directions and intensity of prevailing and other winds are plotted on corresponding bases, as a preliminary to determination of internal structures through ground truth.

Mckee, E. D.; Breed, C. S.

1973-01-01

395

Impossible Whiteness: Race, Gender, and American Identity in Early Twentieth-Century American Literature  

Microsoft Academic Search

In Impossible Whiteness, I reveal whiteness--though oftentimes still an implicit critical assumption of normalcy--as a complex, shifting category in the literature of early twentieth-century America, and show how gender, particularly, disrupts American whiteness. I deconstruct the various ways in which whiteness is defined legally, culturally, and in the marketplace, and demonstrate how Edith Wharton, Anzia Yezierska, and F. Scott Fitzgerald

Tarah Demant

2010-01-01

396

White LED performance  

NASA Astrophysics Data System (ADS)

Two life tests were conducted to compare the effects of drive current and ambient temperature on the degradation rate of 5 mm and high-flux white LEDs. Tests of 5 mm white LED arrays showed that junction temperature increases produced by drive current had a greater effect on the rate of light output degradation than junction temperature increases from ambient heat. A preliminary test of high-flux white LEDs showed the opposite effect, with junction temperature increases from ambient heat leading to a faster depreciation. However, a second life test is necessary to verify this finding. The dissimilarity in temperature effect among 5 mm and high-flux LEDs is likely caused by packaging differences between the two device types.

Gu, Yimin; Narendran, Nadarajah; Freyssinier, Jean Paul

2004-10-01

397

Sand dunes of Taklimakan deset obtained from satellite data  

NASA Astrophysics Data System (ADS)

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

Tsuchiya, K.; Oguro, Y.

398

White light velocity interferometer  

DOEpatents

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

Erskine, David J. (Oakland, CA)

1997-01-01

399

White light velocity interferometer  

DOEpatents

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Erskine, D.J.

1997-06-24

400

White light velocity interferometer  

DOEpatents

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

Erskine, David J. (Oakland, CA)

1999-01-01

401

White light velocity interferometer  

DOEpatents

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Erskine, D.J.

1999-06-08

402

Web White & Blue 2000  

NSDL National Science Digital Library

Released earlier this year, Web White & Blue 2000 is intended to "help voters, journalists, and others use the Internet to learn more about the presidential candidates, their campaigns, their scheduled debates this fall as well as the way the online resources are impacting politics in this presidential election year." The Best of the Best section provides links to election coverage and campaign material from a wide range of sources on the Internet. Beginning on October 1, the Rolling Cyber Debate is intended to provide a forum for candidates and their campaigns to continue debates online between the televised ones. Web White and Blue 2000 is supported by the Markle Foundation.

403

Habitat Development Field Investigations, Miller Sands Marsh and Upland Habitat Development Site, Columbia River, Oregon. Appendix A. Physical and Chemical Inventory.  

National Technical Information Service (NTIS)

Physical and chemical conditions at Miller Sands Island complex seem to control plant growth and ecosystem development. While no chemical factors have been identified that appear to retard plant growth, at several locations (particularly on the older upla...

N. Cutshall V. G. Johnson

1978-01-01

404

Adsorption of DNA to sand and variable degradation rates of adsorbed DNA.  

PubMed Central

Adsorption and desorption of DNA and degradation of adsorbed DNA by DNase I were studied by using a flowthrough system of sand-filled glass columns. Maximum adsorption at 23 degrees C occurred within 2 h. The amounts of DNA which adsorbed to sand increased with the salt concentration (0.1 to 4 M NaCl and 1 mM to 0.2 M MgCl2), salt valency (Na+ less than Mg2+ and Ca2+), and pH (5 to 9). Maximum desorption of DNA from sand (43 to 59%) was achieved when columns were eluted with NaPO4 and NaCl for 6 h or with EDTA for 1 h. DNA did not desorb in the presence of detergents. It is concluded that adsorption proceeded by physical and chemical (Mg2+ bridging) interaction between the DNA and sand surfaces. Degradability by DNase I decreased upon adsorption of transforming DNA. When DNA adsorbed in the presence of 50 mM MgCl2, the degradation rate was higher than when it adsorbed in the presence of 20 mM MgCl2. The sensitivity to degradation of DNA adsorbed to sand at 50 mM MgCl2 decreased when the columns were eluted with 0.1 mM MgCl2 or 100 mM EDTA before application of DNase I. This indicates that at least two types of DNA-sand complexes with different accessibilities of adsorbed DNA to DNase I existed. The degradability of DNA adsorbed to minor mineral fractions (feldspar and heavy minerals) of the sand differed from that of quartz-adsorbed DNA.

Lorenz, M G; Wackernagel, W

1987-01-01

405

Sliding Friction on Wet and Dry Sand  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

406

UV disinfection for onsite sand filter effluent  

SciTech Connect

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

Lowery, J.D.; Romatzick, S.

1982-05-01

407

Sliding friction on wet and dry sand.  

PubMed

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

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

2014-05-01

408

Role of a large marine protected area for conserving landscape attributes of sand habitats on Georges Bank (NW Atlantic)  

USGS Publications Warehouse

Mobile fishing gear reduces seafloor habitat complexity through the removal of structure-building fauna, e.g. emergent organisms that create pits and burrows, as well as by smoothing of sedimentary bedforms (e.g. sand ripples). In this study, we compared the relative abundance of microhabitat features (the scale at which individual fish associate with seafloor habitat) inside and outside of a large fishery closed area (6917 km2) on Georges Bank. Starting in late 1994, the closed area excluded all bottom tending fishing gear capable of capturing demersal fishes. A total of 32 stations were selected inside and outside of the closed area in sand habitats. Video and still photographic transects were conducted at each station using the Seabed Observation and Sampling System (SEABOSS). Seven common (i.e. featureless sand, rippled sand, sand with emergent fauna, bare gravelly sand, gravelly sand with attached-erect fauna, whole shell, shell fragment) and 2 rare (sponges, biogenic depressions) microhabitat types were compared separately. Results showed significant differences in the relative abundance of the shell fragment and sponge microhabitat types between fished and unfished areas. The lack of differences for the other microhabitats may indicate that the level of fishing activity in the area is matched by the system's ability to recover.

Lindholm, J.; Auster, P.; Valentine, P.

2004-01-01

409

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

410

[Possibilities for purification of refuse seepage water by sand containing humic substances].  

PubMed

Sands containing humic substances are proposed for protection of ground water from refuse tip seepage waters which containing heavy metals and organic polluting agents. Such sands are produced and spoiled southern of Leipzig during uncovering of brown coal. Humic acids have qualities such as ion-exchange materials, form hydrogen bondes and are able to form salts and complexes. Besides they can adsorb and include other substances. This properties qualify the humic acids in contact with the grained structure of the sand to interactions with heavy metal ions and organic pollution agents in water such as oils, phenols, surface-active agents and organic phosphorus compounds. The installation of sands containing humic substances on the base of the refuse tip gives chances to prevent the migration of heavy metal ions and organic pollution agents in seepage waters on principle. On the other hand it is possible to use sands containing humic substances for cleaning of seepage waters and recovering of anorganic and organic useful materials. First practical tests with an refuse tip seepage water from the district Erfurt confirm the cleaning effect and the recovering of heavy metals. PMID:2525848

Weise, G; Sohr, J; Lungwitz, J; Zier, H W

1989-04-01

411

Residual diesel measurement in sand columns after surfactant/alcohol washing  

SciTech Connect

A new simple gravimetric technique has been designed to determine residual oil saturation of complex hydrocarbon mixtures (e.g., diesel) in sand column experiments because reliable methods are lacking. The He/N{sub 2} technique is based on drying of sand columns by circulating helium gas to drag oil droplets in a cold trap (liquid nitrogen). With this technique, residual diesel measurement can be performed easily immediately after alcohol/surfactant washing and in the same lab. For high residual diesel content in Ottawa sand (25 to 30 g/kg), the technique is much more accurate ({+-} 2% or 600 mg/kg) than the standard analytical methods for the determination of mineral oil and grease. The average relative error on partial diesel dissolution in sand column estimated after alcohol/surfactant flooding (residual saturation of 10 to 15 g/kg) is as low as 5%. The precision of the He/N{sub 2} technique is adequate to compare relative efficiency of washing solutions when partial extraction of residual oil in Ottawa sand columns is performed. However, this technique is not adapted for determination of traces of oil in sediment or for environmental control of contaminated soils. Each diesel determination by the He/N{sub 2} technique costs less than $8 in chemical products (helium and liquid nitrogen). A simple laboratory drying setup can be built for less than $400 which makes this technique valuable for diesel analyses when a large number of tests are required.

Martel, R.; Gelinas, P.J. [Laval Univ., Quebec City, Quebec (Canada)

1996-01-01

412

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

413

White blood cell count  

Microsoft Academic Search

An association between elevated white blood cell (WBC) count and coronary heart disease (CHD) mortality has been previously observed. However, the relationship between WBC count and CHD mortality independent of cigarette smoking and the possible interaction between WBC count and smoking remains unclear. We examined the association between WBC count and CHD mortality with Cox regression analyses of data from

David W Brown; Wayne H Giles; Janet B Croft

2001-01-01

414

Liquid White Enamel.  

ERIC Educational Resources Information Center

A secondary teacher describes how she has her students use liquid white enamel. With the enameling process, students can create lasting, exciting artwork. They can exercise an understanding of design and color while learning the value of careful, sustained craft skills. (RM)

Widmar, Marge

1985-01-01

415

White Dwarf Stars  

NSDL National Science Digital Library

This NASA site provides information about white dwarfs, produced when stars like our Sun exhaust their nuclear fuel and blow off much of their mass. The site contains an explanation of their properties and composition. Additional links include an introductory article, online quiz, cool facts, FAQ, and other resources.

2007-01-26

416

Snow White 5 Trench  

NASA Technical Reports Server (NTRS)

This image was acquired by NASA's Phoenix Mars Lander's Robotic Arm Camera on the 35th Martian day of the mission, or Sol 34 (June 29, 2008), after the May 25, 2008, landing. This image shows the trench informally called 'Snow White 5.' The trench is 4-to-5 centimeters (about 1.5-to-1.9 inches) deep, 24 centimeters (about 9 inches) wide and 33 centimeters (13 inches) long.

Snow White 5 is Phoenix's current active digging area after additional trenching, grooming, and scraping by Phoenix's Robotic Arm in the last few sols to trenches informally called Snow White 1, 2, 3, and 4. Near the top center of the image is the Robotic Arm's Thermal and Electrical Conductivity Probe.

Snow White 5 is located in a patch of Martian soil near the center of a polygonal surface feature, nicknamed 'Cheshire Cat.' The digging site has been named 'Wonderland.'

This image has been enhanced to brighten shaded areas.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

417

Splitting White Light  

NSDL National Science Digital Library

In this optics activity, learners split white light into all its component colors using three household items: a compact disc, dishwashing liquid, and a hose (outside). In each experiment, learners split light through a different color separation process, including dispersion, interference and diffraction. This resource includes an explanation of each process as well as links to three articles about color and light.

America, Optical S.

2008-01-01

418

White Sea - Russia  

NASA Technical Reports Server (NTRS)

At bottom center of this true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from April 13, 2001, the White Sea in western Russia is becoming free of ice in its southern extent. Meanwhile, the blue-green waters along the coast of the peninsula jutting out into the Barents Sea to the northeast could be due to a phytoplankton bloom.

2002-01-01

419

Exploring how sand ramps respond to Quaternary environmental change in Southern Africa  

NASA Astrophysics Data System (ADS)

The current climate of southern Africa is particularly complex and interesting due to the interaction of several climatic systems. However, reconstructions of how these systems behaved in the past, and how the environment responded, have been hampered by a general paucity of records and poor chronological control. Sand ramps may provide the potential to improve palaeoenvironmental reconstructions of southern Africa (and beyond). Formed against a topographic barrier, sand ramps include a combination of aeolian, fluvial and colluvial deposits in varying proportions. Therefore, they have the potential to record changes in moisture availability, circulation patterns and sediment supply which can be independently dated using luminescence dating. Nevertheless relatively little attention has been paid to these features and thus the environmental controls on their formation are not yet fully understood. In particular, there is debate as to whether they reflect deposition during a 'window of opportunity' in which high-magnitude, low-frequency events are recorded (Bateman et al. 2012) or whether they record more gradual, cyclic climate change (Bertram, 2003) or even if there is a uniform control on their formation. This research aims to investigate how sand ramps respond to environmental change and what they can tell us about the paleoenvironment of southern Africa. This poster displays preliminary results based on initial field investigation. This confirmed sand ramps to be ubiquitous in southern Africa and that they record a complex interaction of aeolian, fluvial and colluvial deposits which appears to differ between sand ramps. Preliminary luminescence dating results and sedimentology are displayed for two sand ramps, one from south west Namibia the other from the Karoo region of South Africa.

Rowell, Alex; Thomas, David; Bailey, Richard

2014-05-01

420

The White Sea, Russia  

NASA Technical Reports Server (NTRS)

Editor's Note: The caption below, published on May 10, 2001, is incorrect. According to Masha Vorontsova, director of the International Fund for Animal Welfare in Moscow, the situation with the seal pups in the White Sea is normal. There is no disaster and there never was. For more details, refer to the article entitled 'No Danger' on the New Scientist home page. The Earth Observatory regrets the earlier errant report. Original Caption According to the Russian Polar Research Institute for Fisheries and Oceanography, between 250,000 and 300,000 Greenland seal pups face death by starvation over the next two months due to a cruel trick by mother nature. The seals, most of them less than two months old, are trapped on ice sheets that remain locked in the White Sea, located near Archangel in Northern Russia. Typically, during the spring thaw the ice sheets break up and flow with the currents northward into the Barents Sea, the seals' spring feeding grounds. The seal pups hitch a ride on the ice floes, living on their own individual stores of fat until they arrive in the Barents Sea. Their mothers departed for the Barents Sea weeks ago. In a normal year, the seal pups' trip from the White Sea out to the Barents takes about six weeks and the seals have adapted to rely upon this mechanism of mother nature. During their yearly migration, the mother seals usually stay with their pups and feed them until their pelts turn from white to grey--a sign that the pups are mature enough to swim and feed themselves. Unfortunately, this year unusually strong northerly winds created a bottleneck of ice near the mouth of the white sea, thus blocking the flow of ice and trapping the pups. These true-color images of the White Sea were acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. This image, taken May 2, 2000 that there is usually much less ice in the White Sea this time of year as most of it is typically en route to the Barents Sea.

2002-01-01

421

Exploring Whiteness: A Study of Self Labels for White Americans.  

ERIC Educational Resources Information Center

Examines the preferences and meanings of labels for White Americans as discursively defined expressions of identity, after preliminary revelations of resistance by Whites to self-labeling was seen. Surveys 371 White undergraduate students, rating seven labels regarding preference and discussing feelings about self-labeling. Reveals that the most…

Martin, Judith N.; Krizek, Robert L.; Nakayama, Thomas K.; Bradford, Lisa

1996-01-01

422

Thermal diffusivity of peat, sand and their mixtures at different water contents  

NASA Astrophysics Data System (ADS)

Thermal diffusivity of peat, sand and their mixtures at different water contents was studied using the unsteady-state method described in (Parikh et al., 1979). Volume sand content in studied samples was 0 % (pure peat), 5, 10, 15, 20, 30, 40, 50, 55 and 62 % (pure sand). Thermal diffusivity of air-dry samples varied from 0.6×10-7m2s-1 for pure peat to 7.0×10-7m2s-1 for pure sand. Adding 5 and 10 vol. % of sand didn't change the thermal diffusivity of studied mixture as compared with that of the pure air-dry peat. Adding 15 % of sand resulted in significant increase of thermal diffusivity by approximately 1.5 times: from 0.6×10-7m2s-1 to 0.9×10-7m2s-1. It means that small amounts of sand with separate sand particles distributed within the peat don't contribute much to the heat transfer through the studied media. And there is a kind of threshold between the 10 and 15 vol. % of sand, after which the continuous sandy chains are formed within the peat, which can serve as preferential paths of heat transport. Adding 20 and 30 % of sand resulted in further increase of thermal diffusivity to 1.3×10-7m2s-1 and 1.7×10-7m2s-1, which is more than two and three times greater than the initial value for pure peat. Thermal diffusivity vs. moisture content dependencies had different shapes. For sand contents of 0 to 40 vol. % the thermal diffusivity increased with water content in the whole studied range from air-dry samples to the capillary moistened ones. For pure peat the experimental curves were almost linear; the more sand was added the more pronounced became the S-shape of the curves. For sand contents of 50 % and more the curves had a pronounced maximum within the range of water contents between 0.10 and 0.25 m3m-3 and then decreased. The experimental k(?) curves, where k is soil thermal diffusivity, ? is water content, were parameterized with a 4-parameter approximating function (Arkhangelskaya, 2009, 2014). The suggested approximation has an advantage of clear physical interpretation: the parameters are (1) the thermal diffusivity of the dry sample; (2) the difference between the highest thermal diffusivity at some optional water content and that of the dry sample; (3) the optional water content at which the thermal diffusivity reaches its maximum; (4) half-width of the peak of the k(?) curve. The increase of sand contents in studied mixtures was accompanied by the increase of the parameters (1), (2) and (4) and the decrease of the parameter (3). References Parikh R.J., Havens J.A., Scott H.D., 1979. Thermal diffusivity and conductivity of moist porous media. Soil Science Society of America Journal 43, 1050-1052. Arkhangel'skaya T.A., 2009. Parameterization and mathematical modeling of the dependence of soil thermal diffusivity on the water content. Eurasian Soil Science 42 (2), 162-172. doi: 10.1134/S1064229309020070 Arkhangelskaya T.A., 2014. Diversity of thermal conditions within the paleocryogenic soil complexes of the East European Plain: The discussion of key factors and mathematical modeling // Geoderma. Vol. 213. P. 608-616. doi 10.1016/j.geoderma.2013.04.001

Gvozdkova, Anna; Arkhangelskaya, Tatiana

2014-05-01

423

White matter of the brain  

MedlinePLUS

White matter is tissue found in the brain. It contains nerve fibers. Many of these nerve fibers (axons) are ... fat called myelin. The myelin gives the white matter it's color. Myelin acts as an insulator. It ...

424

New production techniques for Alberta oil sands  

SciTech Connect

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

Carrigy, M.A.

1986-12-19

425

Alberta ERCB lists active oil sands projects  

SciTech Connect

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

Not Available

1987-03-01

426

Thermal recovery of hydrocarbon from tar sands  

Microsoft Academic Search

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

D. A. Redford; S. M. Creighton

1977-01-01

427

Developing Alberta's oil sands, 1920--2002  

Microsoft Academic Search

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

Paul Anthony Chastko

2002-01-01

428

Secondary froth wash. [Oil Sand Processing  

Microsoft Academic Search

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

Kaminsky

1973-01-01

429

Economic Potential of Domestic Tar Sands.  

National Technical Information Service (NTIS)

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

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

1978-01-01

430

Externally catalyzed epoxy for sand control  

Microsoft Academic Search

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

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

1972-01-01

431

EASTERN TIGHT SANDS, A STIMULATION ASSESSMENT  

Microsoft Academic Search

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

Steven McKetta; Gregory Koziar; Louis Cook

1980-01-01

432

FERC decontrols tight sands, stripper gas  

Microsoft Academic Search

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

1984-01-01

433

Porosity and Permeability of Tight Sands  

Microsoft Academic Search

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

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

1984-01-01

434

AMPEROMETRIC TITRATION OF THORIUM IN MONAZITE SANDS  

Microsoft Academic Search

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

J. J. Burastero; R. W. Martres

1962-01-01

435

A note on tidally generated sand waves  

NASA Astrophysics Data System (ADS)

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

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

2003-06-01

436

Geology of the Athabasca oil sands  

Microsoft Academic Search

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

G. D. Mossop

1980-01-01

437

Development of the oil sands of Canada  

Microsoft Academic Search

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

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

1978-01-01

438

Oil sands: resource, recovery, and industry  

Microsoft Academic Search

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

C. H. Cox; G. L. Baughman

1980-01-01

439

Geology of the Athabasca oil sands  

Microsoft Academic Search

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

G. D. Mossop

1980-01-01

440

Bitumen-Sand Mixes for Road Bases.  

National Technical Information Service (NTIS)

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

F. H. P. Williams

1968-01-01

441

EXPRESSING SUPPLY LIMITATION IN SAND SALTATION  

EPA Science Inventory

Saltation-driven sandblasting is the most effective producer