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1

White Sands Test Facility  

NASA Astrophysics Data System (ADS)

This is an overview of the White Sands Test Facility's role in ensuring the safety and reliability of materials and hardware slated for launch aboard the Space Shuttle. Engine firings, orbital flights debris impact tests, and propulsion tests are featured as well as illustrating how they provide flight safety testing for the Johnson Space Center, other NASA centers, and various government agencies. It also contains a historical perspective and highlights of major programs that have been participated in as part of NASA.

2

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

3

Early diagenesis of eolian dune and interdune sands at White Sands, New Mexico  

USGS Publications Warehouse

The degree of early diagenesis in eolian dune and interdune sands at White Sands, New Mexico, is largely a function of the relationship between sand location and the water table. Most active and vegetation-stabilized dune sands are in the vadose zone, whereas interdune sands are in the capillary fringe and phreatic zones. Crystallographically controlled dissolution of the framework gypsum grains results in elongate, prismatic etch pits on sand grains from the capillary fringe and phreatic zones, whereas dissolution of sand grains in the vadose zone is slight, causing minute irregularities on grain surfaces. Vadose water percolating through the sand is manifest as meniscus layers. Consequently, dune sands in the vadose zone are cemented mainly by meniscus-shaped gypsum at grain contacts. Pendant cements formed on the lower margins of some sand grains. Cementation in the capillary fringe and the phreatic zone is more extensive than the vadose regardless of strata type. Typically, well-developed gypsum overgrowths form along the entire edge of a grain, or may encompass the entire grain. Complex diagenetic histories are suggested by multiple overgrowths and several episodes of dissolution on single grains, attesting to changing saturation levels with respect to gypsum in the shallow ground water. These changes in saturation are possibly due to periods of dilution by meteoric recharge, alternating with periods of concentration of ions and the formation of cement due to evaporation through the capillary fringe. ?? 1988.

Schenk, C. J.; Fryberger, S. G.

1988-01-01

4

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

5

Testing Planetary Radiative Transfer Models via Remote Sensing of Gypsum Sands in White Sands National Monument  

Microsoft Academic Search

Directional reflectance and emission spectra for particulate materials are governed by the mineralogy, grain size, packing, and topography of the sample observed. White Sands National Monument, as the largest homogeneous gypsum dune field in the world, provides a unique in-situ environment in which to isolate the textural components of spectra and determine the ability of remote sensing models to retrieve

K. L. Siebach; R. E. Arvidson; J. Boettger; S. Bova; P. Murrey; M. Rudd; S. Spera; T. Stein; M. Witchger

2010-01-01

6

Renewable Energy Opportunities at White Sands Missile Range, New Mexico  

SciTech Connect

The document provides an overview of renewable resource potential at White Sands Missile Range (WSMR) based primarily upon analysis of secondary data sources supplemented with limited on-site evaluations. The effort was funded by the U.S. Army Installation Management Command (IMCOM) as follow-on to the 2005 DoD Renewable Energy Assessment. This effort focuses on grid-connected generation of electricity from renewable energy sources and also ground source heat pumps (GSHPs) for heating and cooling buildings, as directed by IMCOM.

Chvala, William D.; Solana, Amy E.; States, Jennifer C.; Warwick, William M.; Weimar, Mark R.; Dixon, Douglas R.

2008-09-01

7

Experimental evidence for costs of parasitism for a threatened species, White Sands pupfish (Cyprinodon tularosa)  

Microsoft Academic Search

Summary 1. We used field and experimental data to test if white grub parasites (Diplostomatidae) are costly to White Sands pupfish (Cyprinodon tularosa), a threatened species restricted to four sites in the Chihuahuan desert, New Mexico. 2. Of the four populations of C. tularosa, two are native and two are introduced. The two native populations (Malpais Spring and Salt Creek)

MICHAEL L. COLLYER; CRAIG A. STOCKWELL

2004-01-01

8

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

9

Convergent evolution and divergent selection: lizards at the White Sands ecotone.  

PubMed

Ecological transition zones, where organismal phenotypes result from a delicate balance between selection and migration, highlight the interplay of local adaptation and gene flow. Here, I study the response of an entire species assemblage to natural selection across a common ecotone. Three lizard species, distributed along a dramatic environmental gradient in substrate color, display convergent adaptation of blanched coloration on the gypsum dunes of White Sands National Monument. I investigate the role of gene flow in modulating phenotypic response to selection by quantifying color variation and genetic variation across the ecotone. I find species differences in degree of background matching and in genetic connectivity of populations across the ecotone. Differences among species in phenotypic response to selection scale precisely to levels of genetic isolation. Species with higher levels of gene flow across the ecotone exhibit less dramatic responses to selection. Results also reveal a strong signal of ecologically mediated divergence for White Sands lizards. For all species, phenotypic variation is better explained by habitat similarity than genetic similarity. Convergent evolution of blanched coloration at White Sands clearly reflects the action of strong divergent selection; however, adaptive response appears to be modulated by gene flow and demographic history and can be predicted by divergence-with-gene-flow models. PMID:16475095

Rosenblum, Erica Bree

2005-11-07

10

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

National Technical Information Service (NTIS)

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 work performed by the staff of Pacific Northwest...

E. Chapman F. C. Rutz J. C. Barnard M. S. Pekour W. J. Shaw

2009-01-01

11

Final Programmatic Environmental Impact Statement for Defense Threat Reduction Agency (DTRA) Activities on White Sands Missile Range, New Mexico.  

National Technical Information Service (NTIS)

This Record of Decision (ROD) announces final Agency determinations and approvals prepared by the Defense Threat Reduction Agency (DTRA) in response to a proposal to increase DTRA testing activities at the White Sands Missile Range (WSMR), New Mexico. The...

2007-01-01

12

GroundwaterGeochemistry,SeasonalChangesandControlsonEolianMorphology.WhiteSandsNationalMonument,NewMexi co,TX  

Microsoft Academic Search

The White Sands of New Mexico is composed of transverse, barchan and parabolic dunes formed of gypsum sand. Transverse dunes pass downwind into barchans and then vegetated parabolic dunes. This study focuses on the transition from barchan dunes that migrate rapidly (12 m\\/year) through an unvegetated landscape, to isolated parabolic dunes migrating at 1 to 2 m\\/year through vegetated, stabilized

J. M. Rose; R. P. Langford; M. J. Cueto

2005-01-01

13

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.

14

Computational simulations of blown sand flux over complex microtopography  

Microsoft Academic Search

Current research on sand saltation concentrates on wind tunnel experiment, theoretical analysis and numerical simulation of sand saltation at ideal and controllable conditions, for example, time-invariant wind speed and flat sand bed. However, these somehow idealized theoretical analyses and numerical simulations can not accurately predict sand movements in field environments, which are generally composed of surface obstacles including dunes and

Huang Ning; Shi Feng

2009-01-01

15

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

Microsoft Academic Search

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

R. P. Langford

2001-01-01

16

Complex resistivity signatures of ethanol in sand-clay mixtures.  

PubMed

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. PMID:23603518

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

2013-03-29

17

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

18

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

19

Lean Implementation at White Sands Missile Range: A Case Study of Lean Thinking Applied in a Government Organization.  

National Technical Information Service (NTIS)

In this Joint Applied Project, we study application of lean thinking at White Sands Missile Range, an Army Major Range and Test Facility Base (MRTFB), tasked with developmental Test and Evaluation (T&E) as its primary mission. We interviewed a representat...

D. C. Bissell D. D. Telles M. S. Garcia

2006-01-01

20

Deciphering complex soil/site formation in sands  

NASA Astrophysics Data System (ADS)

This paper summarizes aspects of the geoarchaeological research at two adjacent multi-component archaeological sites, 13JP86 and 13JP87, along Indian Creek in central Iowa, USA. The sites, both recently salvaged but now destroyed, formed in late Pleistocene sands reworked from glacial sediments that emanated from the wasting Des Moines Lobe glacier some 13,000-14,000 years ago. The soils contained shallowly dispersed and mixed artifacts that span the Paleoindian-to-historic cultural spectrum. In open areas, as at Indian Creek, site formation processes equate to natural soil genetic processes, plus human imprints. Cultural materials, once deposited, become part of the soil and subject to dynamic soil processes. These soils had reasonably well expressed Ap, A, and E horizons that collectively formed thick one-layered biomantles, underlain by well expressed argillic Bt horizons. The biomantles had been well bioturbated, deeply in some pedons, but still exhibited organized A and E horizons. The Bt horizons were also bioturbated, though less so, and consisted of multiple thin to thick sandy clay bands, termed illuvial clay lamellae (icl's). The icl's contained modest to appreciable amounts of illuvial clay as bridges between grains, and as diffuse splotches and blebs separated by less clayey, E horizon-like interlamellar sandy zones. Deeper and less bioturbated E-like sandy zones had accumulated so much clay that they had coalesced with icl's into thick, complexly banded argillic Bt horizons. The process histories of the sandy pedons were obviously extremely complex. The geoarchaeological aspects of the project, which were mainly complex pedologic ones, were largely interpreted by drawing on the genetic principles of dynamic denudation to explain soil/site evolution. Many questions were raised, and most were answered under these principles. New concepts and perspectives were gained in this study, and the resulting interpretive scenarios carry explanatory implications for sandy soils everywhere, whether charged with cultural materials or not.

Johnson, D. L.; Johnson, D. N.; Benn, D. W.; Bettis, E. A., III

2008-10-01

21

Computational simulations of blown sand fluxes over the surfaces of complex microtopography  

Microsoft Academic Search

Studies of sand saltation are currently concentrating on wind tunnel experiments, theoretical analyses and numerical simulations under ideal as well as controllable conditions. These theoretical analyses and numerical simulations cannot accurately predict sand movements in field environments. In this paper, we simulate wind field patterns for two different surfaces of complex microtopography using the computational fluid dynamic model, FLUENT. To

Shi Feng; Huang Ning

2010-01-01

22

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

23

Phenotypic plasticity and contemporary evolution in introduced populations: evidence from translocated populations of white sands pupfish ( Cyrpinodon tularosa )  

Microsoft Academic Search

Contemporary evolution has been shown in a few studies to be an important component of colonization ability, but seldom have\\u000a researchers considered whether phenotypic plasticity facilitates directional evolution from the invasion event. In the current\\u000a study, we evaluated body shape divergence of the New Mexico State-threatened White Sands pupfish (Cyprinodon tularosa) that were introduced to brackish, lacustrine habitats at two

Michael L. Collyer; Craig A. Stockwell; Dean C. Adams; M. Hildegard Reiser

2007-01-01

24

Turbulence eddy dissipation rates from radar observations at 5-20 km at White Sands Missile Range, New Mexico  

Microsoft Academic Search

A climatology of the eddy dissipation rate is presented based on the widths of the Doppler radar spectra observed by the 50-MHz, clear-air profiler located at White Sands Missile Range, New Mexico. The observations are from radar beams 15° off zenith and extend from about 5 to 20 km altitude. The data are nearly continuous over the 5-year period 1991-1995.

G. D. Nastrom; F. D. Eaton

1997-01-01

25

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

26

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

Microsoft Academic Search

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

W. R. Hansen; J. C. Rodgers

1985-01-01

27

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 4. A new species of Schinia H?bner, 1818 (Lepidoptera, Noctuidae, Heliothinae)  

PubMed Central

Abstract In 2006 the U.S. National Park Service initiated a long term study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico. Schinia poguei sp. n., described here, was discovered in 2007, the second year of the study. The male and female adult moths and genitalia are illustrated.

Metzler, Eric H.; Forbes, Gregory S.

2011-01-01

28

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

29

Heaven in a grain of sand'—Patrick White's Contemporary Vision  

Microsoft Academic Search

Australia's Nobel Prize-winning writer, Patrick White, has unequivocally stated: ?Religion—that's behind all my novels….? He remains acutely aware of the challenge before a writer with such preoccupations in the context of the contemporary world and his writing strategies present a range of subtleties designed, it would appear, to negotiate the challenges its dominant secular ethos . The dismissal of the

W. Australia

30

The Lepidoptera of White Sands National Monument, Otero County, New Mexico, USA 2. Rediscovery and description of Sparkia immacula (Grote, 1883) (Noctuidae, Noctuinae, Hadenini)  

PubMed Central

Abstract In 2006 the U.S. National Park Service initiated a long term study of the Lepidoptera at White Sands National Monument, Otero County, New Mexico. Sparkia immacula (Grote, 1883), previously known only from historical specimens collected in Arizona and New Mexico, was discovered in the Monument in 2007 during the second year of the study. The adult moths and male and female genitalia are illustrated for the first time.

Metzler, Eric H.; Forbes, Gregory S.

2011-01-01

31

Microbial Nitrogen and Sulfur Cycles at the Playa and Playa-lake Deposits of White Sands National Monument, New Mexico  

NASA Astrophysics Data System (ADS)

A deflationary basin, Alkali Flat, of White Sands National Monument holds active playas and a playa lake, which allows for an excellent comparison of these different (hyper)saline habitats. Playa lakes are commonly studied as extreme hypersaline environments, however from our data, less studied playa sediments and coarse selenite crystals showed to be more biologically challenging environments. The Flat contains dome structures composed of coarse selenites, an alternative newly discovered microbial habitat. A comparison of environmental physicochemical conditions and molecular biology was used to determine the characteristics of microbial habitats and communities and to decipher nodes of nitrogen and sulfur cycles. On Mars, the presence of sulfate rich playa deposits has been suggested for the deposits discovered by the Opportunity rover at Meridiani Planum. Recently, it has been suggested that the playa settings extended to a larger, Arabia Terra, zone of groundwater upwelling. The study of terrestrial analogue site with playa settings, such as Alkali Flat from New Mexico, provides an analogue system to explore and characterize the proposed habitable zones and their potential biosignatures. At White Sands, playa lake deposits held up to 55wt.% of water within the surface mirabilite crust, bottom layers composed of sulfates, clay, halite, and carbonates had less water. The lake deposits hold the only setting with reducing chemistry that was detected in the layers beneath the crust (with 3.42:1 ammonium (NH4) over nitric oxides (NO)). Playa sediments were 10 times drier than the playa lake deposits and had patchy surface crust of halite and gypsum. Selenite crystals were the driest among studied habitats (0.16wt.% H2O). Playa sediments and selenites contained 9.49 and 3.9 times more NO than NH4, suggesting importance of nitrification processes in these settings. Nitrogen fixation genes were detected only in playa lake deposits. A variety of ammonium oxidation genes (?-, ?-proteobacteria, archaea) were detected in all of the samples, which supports the nitrification hypothesis suggested by nitrogen analyses. Denitrification genes, including anammox bacteria, were detected in all of the settings, showing that microbial organisms from the analyzed habitats do have abilities to complete the nitrogen metabolic circuit. A variety of sulfur bearing minerals provides nutrient compounds necessary for microbial life. Genetic assaying identified the presence of sulfate reducing microbes in all of the samples, as well as anoxyphototrophs and organisms with the APS reductase. The detected organisms have the ability to reduce sulfate and utilize reduced sulfur compounds and to oxidize them back to sulfate. Detected variety of carbonate precipitates associated with biofilms confirms the presence of sulfate reducing microbes in playa lake deposits and selenites. However, absence of carbonates and the presence of Fe and K chlorites at the playa sediments suggest likely stunted microbial sulfate reduction. Indicating microbial response to multiple environmental stress (drought and high salinity) and possible limiting conditions for, at least, microbial sulfate reduction reached in playa surface habitats.

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

2011-12-01

32

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

33

Nature and distribution of Ni(II) complexes in oil sand asphaltenes  

SciTech Connect

The interactions of asphaltenes with two Ni(II) porphyrins and a non-porphyrin complex in organic medium and with nickel (II) sulfate in aqueous solutions were investigated. The nickel (II) acetylacetonate-asphaltene reaction in chloroform solution occurred rapidly. No saturation Ni(II) content in asphaltenes after this reaction was observed up to a Ni(II) content of 174 ..mu..mole Ni/g. It was shown that discrete Ni(acac)/sub 2/ molecule adsorbs weakly on asphaltenes but that the dominant reaction involved acetylacetonate ligand replacement by asphaltenes functional groups. Nickel (II) mesoporphyrin IX dimethyl ester (Ni-DME) was adsorbed by oil-sand asphaltenes to a greater extent than nickel (II) octaethylphorphyrin (Ni-OEP) possibly due to hydrogen bonding between the ester groups of Ni-DME and asphaltene functional groups. The Ni(II) porphyrin adsorption on asphaltenes in the chloroform solution and not during asphaltene precipitation. The Cu(II) content in asphaltenes after reaction with Cu(acac)/sub 2/ in chloroform under similar reaction conditions used for Ni(acac)/sub 2/ - asphaltene reaction indicated that Cu(II) was taken up by asphaltenes to a smaller extent than Ni(II). The reaction rate of the interaction between asphaltenes and aqueous solutions of nickel (II) sulfate was slow, and dependent on the interfacial contact between the aqueous and organic phases.

Nguyen, S.N.

1986-01-01

34

Test wells T23, T29, and T30, White Sands Missile Range and Fort Bliss Military Reservation, Dona Ana County, New Mexico  

USGS Publications Warehouse

Three test wells, T23, T29, and T30, were drilled in south-central New Mexico as part of a joint military training program sponsored by the U.S. Army in November 1982. Test well T23 was drilled as an exploratory and monitoring well in the proposed Soledad well field at the Fort Bliss Military Reservation. Test wells T29 and T30 were drilled at White Sands Missile Range. Test well T29 was drilled as an observation well in the vicinity of the outfall channel from the sewage treatment plant. Test well T30 was drilled as an observation well for a landfill south of the well site. Information obtained from these wells includes lithologic logs for all wells and borehole-geophysical logs from the cased wells for test wells T29 and T30. (USGS)

Myers, R. G.; Pinckley, K. M.

1984-01-01

35

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

36

Gedrag van Enkele Gesubstitueerde Benzenen, Bestrijdingsmiddelen en Komplexvormers Tijdens Langzame Zandfiltratie (Behaviour of Some Substituted Benzenes, Pesticides and Complexing Agents during Slow Sand Filtration).  

National Technical Information Service (NTIS)

A pilot plant study has been conducted to investigate the behavior of organic micropollutants during slow sand filtration. The main goal of the study was to obtain information on the removal of some substituted benzenes, pesticides, synthetic complexing a...

J. Hrubec G. den Engelsman A. C. de Groot R. S. den Hartog A. P. J. M. de Jong

1990-01-01

37

Vulnerability and fate of a coastal sand dune complex, Rosetta-Idku, northwestern Nile Delta, Egypt  

NASA Astrophysics Data System (ADS)

Types, distribution, and origin of recent sand dunes between Rosetta and Idku, in the western sector of the Nile Delta, Egypt were investigated. Sand samples from the dunes, beach, and seafloor were studied for grain size distribution and mineralogical composition. It has been found that most of the dunes in the study area have been subjected to deterioration and removal due to the construction of buildings and the International Coastal Highway. The remnant constitutes a damaged belt of foredunes that extends from El Bouseily village to the west of Idku town. The dune’s origin is interpreted to be the result of coastal drifting and the subsequent transport of sediments of the former Canopic Nile branch eastward by the predominant longshore current and by aeolian processes. The blown sand grains accumulated to form a belt of coastal sand dunes of original longitudinal and crescentic forms. Urbanization of the coast has severely altered the landscape. The study area is considered vulnerable to the impacts of climate change and the expected rise in sea level. The outcome of potential sea level rise is serious; erosion problems are expected to be exacerbated and vast areas from land and property would be lost. Thus, protection and preservation the remaining dunes in the study area are vital requirements for shore protection.

El Banna, Mahmoud M.

2008-05-01

38

Efficient white organic light-emitting diodes based on iridium complex sensitized copper complex  

NASA Astrophysics Data System (ADS)

Efficient double emission-layer white organic light-emitting diodes comprising a yellow emission from bis[(4,6-difluorophenyl)-pyridinato-N,C2](picolinato)Ir(III) (FIrpic) sensitized [Cu(bis[2-(diphenylphosphino)phenyl]ether) (6,7-Dicyanodipyrido[2,2-d : 2', 3'-f] quinoxaline)]BF4(CuI complex) and a blue emission from 4, 4'-bis(2,2'-diphenylvinyl)-1, 1'-biphenyl (DPVBi) were demonstrated. The emission spectrum can be fine tuned by effectively controlling the thicknesses of the two emission layers. The optimized device with 18 nm FIrpic and the CuI complex codoped 4, 4'-N,N'-dicarbazole-biphenyl layer and 12 nm DPVBi layer shows a maximum current efficiency of 8.5 cd A-1, a maximum power efficiency of 5.3 lm W-1 and a maximum luminance of 3290 cd m-2. Moreover, the device exhibits a CIE coordinate of (0.345, 0.357) at a bias of 8 V and a slight colour variation with increased voltage from 6 to 16 V.

Su, Zisheng; Li, Wenlian; Chu, Bei; Xu, Maoliang; Che, Guangbo; Wang, Dan; Han, Liangliang; Li, Xiao; Zhang, Dongyu; Bi, Defeng; Chen, Yiren

2008-04-01

39

Multi emissive layer type white organic light emitting diode based on zinc metal complexes  

NASA Astrophysics Data System (ADS)

White organic light emitting diodes were fabricated using two zinc complexes bis(2-(2-hydroxyphenyl)benzoxazolato) zinc(II) [Zn(HPB)2] and bis(5,7-dimethyl-8-hydoxyquinolinato) zinc(II) [Zn(Me2q)2]. Zn(HPB)2 emitted light in blue region while Zn(Me2q)2 emitted light in orange region of the visible spectrum. Hence, we achieved white light by combining the two complimentary colors of the materials and by optimizing their thickness as emissive layer. Commission Internationale de l'Eclairage coordinates of the device, with 35 nm thickness of Zn(HPB)2 and 13 nm thickness of Zn(Me2q)2, were (0.28, 0.36) which were well within the white region. The device emitting white light showed maximum luminescence of 2582 cd/m2 at 19 V.

Kumar, Amit; Srivastava, Ritu; Kumar, Arunandan; Kamalasanan, Modeeparampil N.; Singh, Ishwar

2012-10-01

40

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

41

Occult White Matter Damage Contributes to Intellectual Disability in Tuberous Sclerosis Complex  

ERIC Educational Resources Information Center

|Whether patients with tuberous sclerosis complex (TSC) have brain normal-appearing white matter (NAWM) damage and whether such damage contributes to their intellectual disability were examined in 15 TSC patients and 15 gender- and age-matched healthy controls using diffusion tensor imaging (DTI). Histogram and region of interest (ROI) analyses of…

Yu, Chunshui; Lin, Fuchun; Zhao, Li; Ye, Jing; Qin, Wen

2009-01-01

42

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

43

Nonseptic diseases associated with the hoof complex: keratoma, white line disease, canker, and neoplasia.  

PubMed

This article addresses nonseptic diseases associated with the hoof complex, namely keratoma, white line disease, canker, and neoplasia. Keratoma is an uncommon cause of lameness, which may be surgically removed. White line disease, a keratolytic process on the solar surface of the hoof, is treated with therapeutic farriery and resection of the hoof wall when appropriate. Equine canker is an infectious process that results in development of a chronic hypertrophy of the horn-producing tissues. Neoplasia involving the equine foot is rare, and melanoma is the most common type of neoplasm reported. PMID:22981198

Redding, W Rich; O'Grady, Stephen E

2012-08-01

44

White emission phosphors based on Dy3+-doped into anhydrous rare-earth benzenetricarboxylate complexes  

NASA Astrophysics Data System (ADS)

White light emitting rare earth anhydrous complexes RE(TMA):Dy3+ (RE3+ = Y3+ and Lu3+) containing the trimesic acid ligands (TMA) were synthesized and characterized by elemental analysis, X-ray diffraction patterns, thermogravimetric analysis and infrared spectroscopy. The crystallinity and thermostability of these luminescent materials were determined. Since the first excited triplet state (T1: 24,000 cm-1) of TMA ligand is located at higher energy than the main emitting 4F9/2 level (21,000 cm-1) of the Dy3+ ion, TMA can act as efficient luminescent sensitizer in the intramolecular energy transfer of RE(TMA):Dy3+ material. The near-white emission colour originated from the intraconfigurational transitions of Dy3+ ion 4F9/2?6HJ is discussed.

Silva, Ivan G. N.; Kai, Jiang; Felinto, Maria C. F. C.; Brito, Hermi F.

2013-03-01

45

White light-emitting organic electroluminescent device based on a new orange organometallic iridium complexes  

Microsoft Academic Search

We develop the white organic light-emitting diodes (WOLEDs) with a new orange electrophosphorescent emission, and the blue electrofluorescent or electrophosphorescent sensitizer. The new orange phosphorescent sensitizer is the thieno-pyridine framework organo-iridium complexes (PO-01). The blue phosphorsensitized electrofluorescent is 4,4'-Bis(9-ethyl-3-carbazovinylene)-1,1'- biphenyl (DSA) doped into 4,4'-Bis(2,2-diphenyl-ethen-1-yl) diphenyl (DPVBi). Beside, the blue phosphorescent sensitizer is Bis(3,5-difluoro-2-(2-pyridyl)phenyl- (2-carboxypyridyl)iridium (FirPic). The Device Type I of

Tien-shou Shieh; Heh-lung Huang; Pey-ching Liu; Mei-Rurng Tseng; Jia-Ming Liu

2007-01-01

46

Sequence stratigraphy of a Pliocene delta complex deposited in an active margin setting, Etchegoin and San Joaquin gas sands, San Joaquin basin, California  

SciTech Connect

Prolific gas sands of the Pliocene Etchegoin and San Joaquin formations of the southern San Joaquin basin, California, are part of a 1300-m thick succession of deltaic sediments that record the final regression of the Pacific Ocean from a tectonically active, restricted basin associated with the California transform margin. Individual field studies, lacking a regional framework and based primarily on electric log data, correlate these gas sands to the extent that individual sands maintain the same stratigraphic level within the succession. However, a high-resolution sequence stratigraphic framework, constructed from recent 3D-seismic data and detailed well log correlations on the Bakersfield Arch area of the basin, indicates that the Pliocene succession is part of a south/southwest prograding delta complex. Therefore, sands climb up-section in the landward direction and grade laterally from deep-water to shallow-water facies. Because lithofacies boundaries cross chronostratigraphic surfaces, previous interpretations of the reservoir architecture are inaccurate. This model increases predictability of reservoir facies by constraining lithofacies mapping and enables interpretation of the effects on deposition of the integrated and inter-related controls of tectonics, eustatic sea-level change, and sediment supply. With this understanding, a well-defined model of the stratal architecture of the Pliocene succession of the southern San Joaquin basin is now possible.

Steward, D.C. (California State Univ., Bakersfield, CA (United States))

1996-01-01

47

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

48

Loss of white matter microstructural integrity is associated with adverse neurological outcome in Tuberous Sclerosis Complex  

PubMed Central

Rationale and Objectives Tuberous Sclerosis Complex (TSC) is a genetic neurocutaneous syndrome in which cognitive and social-behavioral outcomes for patients vary widely in an unpredictable manner. The cause of adverse neurological outcome remains unclear. We investigated the hypothesis that disordered white matter and abnormal neural connectivity are associated with adverse neurological outcome. Materials and Methods Structural and diffusion magnetic resonance imaging was carried out in 40 subjects with TSC (age range 0.5 – 25 years, mean age 7.2 and median age 5 years), 12 of whom had autism spectrum disorders (ASD), and in 29 age-matched controls. Tractography of the corpus callosum was used to define a 3-dimensional volume of interest. Regional averages of four diffusion scalar parameters of the callosal projections were calculated for each subject. These were the average fractional anisotropy (AFA) and average mean, radial and axial diffusivity (AMD, ARD, AAD). Results Subjects with TSC had significantly lower AFA and higher AMD, ARD and AAD values compared to controls. Subjects with TSC and ASD had significantly lower AFA values compared to those without ASD, and compared to controls. TSC subjects without ASD had similar AFA values compared to controls. Conclusion Diffusion tensor scalar parameters provided measures of properties of the three-dimensional callosal projections. In TSC, changes in these parameters may reflect microstructural changes in myelination, axonal integrity, or extracellular environment. Alterations in white matter microstructural properties were associated with TSC and larger changes were associated with TSC and ASD, thus establishing a relationship between altered white matter microstructural integrity and brain function.

Peters, Jurriaan M.; Sahin, Mustafa; Vogel-Farley, Vanessa K.; Jeste, Shafali S.; Nelson, Charles A.; Gregas, Matthew C.; Prabhu, Sanjay P.; Scherrer, Benoit; Warfield, Simon K.

2012-01-01

49

Modeling fluid diffusion in cerebral white matter with random walks in complex environments  

NASA Astrophysics Data System (ADS)

Recent studies with diffusion MRI have shown new aspects of geometric order in the brain, including complex path coherence within the cerebral cortex, and organization of cerebral white matter and connectivity across multiple scales. The main assumption of these studies is that water molecules diffuse along myelin sheaths of neuron axons in the white matter and thus the anisotropy of their diffusion tensor observed by MRI can provide information about the direction of the axons connecting different parts of the brain. We model the diffusion of particles confined in the space of between the bundles of cylindrical obstacles representing fibrous structures of various orientations. We have investigated the directional properties of the diffusion, by studying the angular distribution of the end point of the random walks as a function of their length, to understand the scale over which the distribution randomizes. We will show evidence of qualitative change in the behavior of the diffusion for different volume fractions of obstacles. Comparisons with three-dimensional MRI images will be illustrated.

Levy, Amichai; Cwilich, Gabriel; Buldyrev, Sergey V.; Weeden, Van J.

2012-02-01

50

Booming Sands  

NSDL National Science Digital Library

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

Foundation, Wgbh E.

2007-04-19

51

Regulation of binding of phosphofructokinase to myofibrils in the red and white muscle of the barred sand bass, Paralabrax nebulifer (Serranidae).  

PubMed

The binding of phosphofructokinase (PFK) to myofibrils from the white muscle of the fish Paralabrax nebulifer (Girard, 1854) is sensitive to factors known to be allosteric regulators of PFK activity. PFK in Triton-X-100-extracted muscle remains bound to myofibrils at pH 7.0 and is fully solubilized by increasing the pH to 8.0. The curve describing the pH-dependence of PFK binding to myofibrils is similar in its steepness to pH versus activity curves of PFK at low temperature. Nucleotides are also potent modulators, preventing the association of PFK with myofibrils at concentrations between 20 and 60 mumol l-1 of ATP, ADP, MgATP or GTP, listed in order of effectiveness. PFKs in the red and white muscle extracts differ in their pH-dependence of binding to myofibrils, and their kinetic and regulatory properties (response to citrate, pH and fructose-2,6-bisphosphate). Reversible binding of PFK to myofibrils may be important in the control of glycolysis, especially in the highly glycolytic white muscle fibres. PMID:2974860

Roberts, S J; Lowery, M S; Somero, G N

1988-07-01

52

Investigation of REE adsorption to aquifer sand under different CO2 partial pressures and in the presence or absence of humic substances: Experimental results and surface complexation modeling  

NASA Astrophysics Data System (ADS)

To better understand the mobility and transport of rare earth elements (REE) in groundwater flow systems, the influence of carbonate ions as well as humic substances on REE adsorption onto Carrizo Aquifer sand was investigated as a function of CO2 partial pressures, pH, ionic strength, and initial REE concentrations. Batch adsorption experiments were carried out at room temperature in a glove box under different CO2 partial pressures (i.e., 0 to 0.05 atm). Our experiments show that carbonate ions can either increase or decrease REE adsorption depending on the carbonate ion concentrations or the initial REE concentrations. More specifically, the degree that REEs are adsorbed onto the aquifer sand is inversely related to the amount of solution complexation of REEs with carbonate ions. In addition, our experiments show that in the presence of carbonate ions, increasing pH from neutral pH to more alkaline pH leads to decreases in REE adsorption. The presence of humic substances can also either increase or decrease REE adsorption, depending on the pH range of the solution. Humic substances enhance REE adsorption at pH < 4 and suppress REE adsorption when pH is above 4. Ionic strength has a negligible effect on REE adsorption in dilute solutions, and only when ionic strength was increased to 0.1 M was a decrease in REE adsorption noticeable. Geochemical modeling indicates that at low REE loading condition (i.e., low initial REE concentration at high solid/solution ratio), REE adsorption onto Carrizo sand mainly occurs via surface complexation reactions. However, at high REE loading condition (i.e., high initial REE concentration at low solid/solution ratio), both surface complexation and cation exchange occur in REE adsorption onto Carrizo sand. With the increase of REE loading, cation exchange apparently plays a more important role. According to the model calculations, at high REE loading and relatively low pH, besides cation exchange and surface complexation of free cations, surface complexation of LnCO3+ species is also required to describe REE adsorption under CO2 partial pressures ranging from 0.000316 atm to 0.05 atm. Whereas, at low REE loading (e.g., 10 ?g/kg) or at high pH (> 8), additional surface complexation of Ln(CO3)2- species is necessary to correctly describe REE adsorption. Our modeling calculations also indicate that the ionic strength effect observed in our experiments is mainly due to competition for exchange sites between REEs and Na ions at high ionic strength (i.e., 0.1 M). Surface compelxation only slightly increase REE adsorption at high ionic strength. This is consistent with previous studies that indicate that the ionic strength effect is absent on cation surface complexation onto hydrous ferric oxides. Thus, in natural groundwater-aquifer systems, the mobility and transport of REEs are mainly influenced by the amount and type of solution complexing ligands presented and the groundwater pH.

Tang, J.; Johannesson, K. H.

2010-12-01

53

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

NASA Astrophysics Data System (ADS)

Solid-state light-emitting electrochemical cells (LECs) based on cationic transition metal complexes (CTMCs) exhibit several advantages over conventional light-emitting diodes such as simple fabrication processes, low-voltage operation, and high power efficiency. Hence, white CTMC-based LECs may be competitive for lighting applications. In this chapter, we review previous important works on CTMC-based LECs, such as increasing device efficiency, color tuning, lengthening device lifetime, and shortening turn-on time. Our demonstration of white CTMC-based LECs by using the host-guest strategy is then described.

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

54

Investigating the prevalence of complex fiber configurations in white matter tissue with diffusion magnetic resonance imaging.  

PubMed

It has long been recognized that the diffusion tensor model is inappropriate to characterize complex fiber architecture, causing tensor-derived measures such as the primary eigenvector and fractional anisotropy to be unreliable or misleading in these regions. There is however still debate about the impact of this problem in practice. A recent study using a Bayesian automatic relevance detection (ARD) multicompartment model suggested that a third of white matter (WM) voxels contain crossing fibers, a value that, whilst already significant, is likely to be an underestimate. The aim of this study is to provide more robust estimates of the proportion of affected voxels, the number of fiber orientations within each WM voxel, and the impact on tensor-derived analyses, using large, high-quality diffusion-weighted data sets, with reconstruction parameters optimized specifically for this task. Two reconstruction algorithms were used: constrained spherical deconvolution (CSD), and the ARD method used in the previous study. We estimate the proportion of WM voxels containing crossing fibers to be ?90% (using CSD) and 63% (using ARD). Both these values are much higher than previously reported, strongly suggesting that the diffusion tensor model is inadequate in the vast majority of WM regions. This has serious implications for downstream processing applications that depend on this model, particularly tractography, and the interpretation of anisotropy and radial/axial diffusivity measures. Hum Brain Mapp 34:2747-2766, 2013. © 2012 Wiley Periodicals, Inc. PMID:22611035

Jeurissen, Ben; Leemans, Alexander; Tournier, Jacques-Donald; Jones, Derek K; Sijbers, Jan

2012-05-19

55

Luminescence dating of sand ramps in the Eastern Mojave Desert  

Microsoft Academic Search

Until recently the timing of the movement of sand and accumulation of sand by aeolian processes in the Eastern Mojave Desert has remained the subject of speculation. The results of a luminescence dating program involving 78 samples of material from nine sand ramp complexes have enabled recognition of regional and local patterns of sand accumulation in the Eastern Mojave. The

H. M. Rendell; N. L. Sheffer

1996-01-01

56

Correlation of male genital filaments and female spermathecal ducts in New World sand flies of the Lutzomyia intermedia species complex (Diptera: Psychodidae, Phlebotominae).  

PubMed

The lengths of the male genital filaments and female spermathecal ducts were measured in phlebotomine sand flies of the Lutzomyia intermedia species complex and the ratios between these characters calculated. Ratios for L. intermedia s. s. from Northeast vs Southeast Brazil (Espírito Santo and Minas Gerais), Espírito Santo/Minas Gerais vs Rio de Janeiro/São Paulo and L. intermedia vs L. neivai were significantly different at P < 0.1, 0.05 and 0.01 respectively when compared using ANOVA. The spermathecal ducts and genital filaments of L. intermedia were significantly longer than those of L. neivai (P < 0.01) and could be used to differentiate these species. The taxonomic and biological significance of these differences is discussed. PMID:12973526

Marcondes, Carlos Brisola; Alexander, Bruce

2003-09-08

57

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

PubMed Central

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.

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

2012-01-01

58

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

59

Atlas of Dutch drift sands  

NASA Astrophysics Data System (ADS)

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

Riksen, Michel; Jungerius, Pieter

2013-04-01

60

Cracks as Evidence for Water Evaporation and Condensation Associated with Temperature Changes in Hydrous Sulfate Sands  

Microsoft Academic Search

Mineral-atmospheric water cycling promotes crack formation in the hydrous sulfate (gypsum) sands at White Sands National Monument, New Mexico. A similar water cycling process may promote crack formation in sulfate outcrops on Meridiani Planum, Mars.

G. V. Chavdarian; D. Y. Sumner

2007-01-01

61

A europium(III) organic ternary complex applied in fabrication of near UV-based white light-emitting diodes  

NASA Astrophysics Data System (ADS)

A ?-diketone, 2-acetylfluorene-4,4,4-trifluorobutane-1,3-dione (HAFTFBD), and its three europium(III) complexes, Eu(AFTFBD)3?2H2O, Eu(AFTFBD)3(TPPO)2 and Eu(AFTFBD)3phen, were designed and synthesized, where TPPO was triphenylphosphine oxide and phen was 1,10-phenanthroline. The complexes were characterized by IR, UV-visible, photoluminescence (PL) spectroscopy and thermogravimetric analysis (TGA). The results show that the Eu(III) complexes exhibit a high thermal stability,and wide and strong excitation bands when monitored at 613 nm. Excited by ˜395 nm near UV light, the complexes emitted strong and characteristic red light due to f- f transitions of the central Eu3+ ion, and no emission from the ligands was found. The photoluminescence mechanism of the europium(III) complexes was investigated and proposed as a ligand-sensitized luminescence process. Among the three europium(III) complexes, Eu(AFTFBD)3phen exhibits the highest thermal stability and the most excellent photoluminescence properties. A bright red light-emitting diode was fabricated by coating the Eu(AFTFBD)3phen complex onto an ˜395 nm-emitting InGaN chip, and the LED showed appropriate CIE chromaticity coordinates ( x=0.66, y=0.33). A white LED with CIE chromaticity coordinates ( x=0.32, y=0.32) was prepared with Eu(AFTFBD)3phen as red phosphor, indicating that Eu(AFTFBD)3phen can be applied as a red component for fabrication of near ultraviolet-based white light-emitting diodes.

Wang, H.; He, P.; Liu, S.; Shi, J.; Gong, M.

2009-10-01

62

EPIDEMIOLOGIC FEATURES OF AN INTRACRANIAL ABSCESSATION\\/SUPPURATIVE MENINGOENCEPHALITIS COMPLEX IN WHITE-TAILED DEER  

Microsoft Academic Search

Case records of 683 white-tailed deer (Odocoileus virginianus) submitted to the Southeastern Cooperative Wildlife Disease Study (Georgia, USA) for diagnostic purposes from 1971 to 1989 were reviewed for the occurrence of pyogenic infections of the central nervous system, specifically intracranial abscessation or suppurative meningoencephalitis. These conditions, either alone or in combination, were diagnosed in 24 of 683 (4%) deer. Thirteen

William R. Davidson; Victor F. Nettles; Lynn E. Hayes; Elizabeth W. Howerth; C. Edward Couvillion

63

Sexual Dimorphism in White Campion: Complex Control of Carpel Number Is Revealed by Y Chromosome Deletions  

Microsoft Academic Search

Sexual dimorphism in the dioecious plant white campion (Silene latifolia 5 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

Sevdalin Georgiev; Abdelmalik Aghmir; Guenael Le Merrer; Ioan Negrutiu

1999-01-01

64

Uptake of EDTA-complexed Pb, Cd and Fe by solution- and sand-cultured Brassica juncea  

Microsoft Academic Search

Direct plant uptake of metals bound to chelating agents has important implications for metal uptake and the free-ion activity model. Uptake of hydrophilic solutes such as metal–EDTA complexes is believed to occur via bypass apoplastic flow, but many questions remain about the relative importance and selectivity of this pathway. In this study, Brassica juncea (Indian mustard) plants grown in solution-

Laurel A. Schaider; David R. Parker; David L. Sedlak

2006-01-01

65

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

66

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

67

Sand resistance of sunscreens.  

PubMed

Like water resistance in sunscreens, sand resistance in sunscreens is the ability of the sunscreen to retain its effectiveness while undergoing sand treatment. The influence of the type of sand on the sand resistance of sunscreens has not been described. The sand resistance of a control standard sunscreen, P2, and data on three grades of Quickrete commercial grade sand, #1961, #1962, and #1152, are described. These sands represent a fine sand, a medium sand, and an all-purpose sand. Using the methodology described in the 2007 proposed amendment of the Final Monograph (1) with one exception, we obtained an SPF of 16.5 (1.6) for the control standard, compared to the expected SPF of 16.3 (3.4). After a five-minute treatment of sand #1961, #1962, or #1151, the SPF of the control standard was 18.3 (1.6), 18.4 (2.0), and 17.5 (2.2), respectively. Thus, all three sands exhibited a similar sand-resistance response. Thus, there was no significant difference in the average SPF with and without sand. The medium grade sand, Quickrete commercial grade #1962, was preferred for sand-resistance testing because the fine sand was difficult to remove from the subject's backs and the coarse sand was unpleasant to the subjects. PMID:23193889

Caswell, Michael; Wood, Caryl; Martinez, Alexa

68

Energy Transfer Employing Europium Complex and Blue Phosphorescent Dye and Its Application in White Organic Light-Emitting Diodes  

Microsoft Academic Search

We investigated the energy transfer of a blue phosphorescent molecule, bis[(4,6-difluorophenyl)-pyridinato-N,C2'] (picolinate) iridium(III) (FIrpic), and a red europium complex of tris(dibenzoylmethane)-mono(4,7-dimethyphenanthroline) europium(III) [Eu(dbm)3phen] doped in poly(N-vinylcarbazole) (PVK). The photoluminescence (PL) spectral intensity of a PVK:Eu(dbm)3phen film was increased by FIrpic doping. Additionally, we demonstrated white organic light-emitting devices (OLEDs) employing the energy transfer from a host to dopants, showing the

Yuichi Hino; Hirotake Kajii; Yutaka Ohmori

2007-01-01

69

Physical characteristics of sand injectites  

NASA Astrophysics Data System (ADS)

Almost two hundred years of research is reviewed that focuses on the physical characteristics of sandstone intrusions. It is concerned with mechanisms of sand injection, particularly with fluid-grain transport and sedimentation processes during the remobilization, injection and extrusion of sand. Outcrop and subsurface studies in combination with laboratory experimental data are drawn on to present the state-of-the-art of sand injection. The text covers 1) geometry, internal structure, and microtexture of deformed parent units, injected and extruded sandstones, 2) host-strata and their seal characteristics that contribute to basin-wide overpressure generation, 3) common trigger mechanisms for sand injection such as high magnitude seismicity and the rapid injection of large volumes of fluids, 4) fluid types that drive sand into fractures, 5) hydrofracture mechanisms that induce regional-scale seal failure, 6) liquefaction and fluidization processes that transport sand into fractures, 7) sedimentation processes in fractures, 8) the flow regime of fluidized sand during injection, 9) post-sand-injection fluid flow and diagenesis, 10) porosity and permeability characteristics of injected sandstones and 11) post-sand-injection fluid-flow over geological timescales. Processes of sand remobilization, injection, and extrusion are complex and depend on many interrelated factors including: fluid(s) properties (e.g. pressure, volume, composition), parent unit and host-strata characteristics (e.g. depositional architecture, grain size and distribution, clay-size fraction, thickness, permeability) and burial depth at the time of injection. Many studies report erosional contacts between host strata and injected sands and these record high-velocity, erosive flow during injection. The flow regime is poorly constrained and similar features are interpreted as records of laminar and turbulent flow, or both, during injection. Internal structures are common in sandstone intrusions and can be accounted for by a variety of processes. The interpretational limits largely result from a lack of laboratory experiments that focus on developing analogues for sand injection. The relationship between grain fabric developed during injection and its control on permeability in sandstone intrusions is poorly understood and failure to advance this field of research will hinder the quantitative characterization of sandstone intrusions as fluid-flow conduits during basin evolution. We conclude that future research should focus on: 1) quantification of sediment transport modes under different flow conditions in different fracture dimensions with laboratory data relevant to sand injection; 2) estimation of the effect of injection on the bulk permeability of otherwise low-permeability seals (host strata) so that their effect on fluid flow can be assessed at all scales; and 3) incorporation of sand injection into quantitative basin models. Although an enormous amount of data have arisen from existing studies there remains a need to advance many fields of research related to sand injection so that the significance of these important structures can be fully appreciated in the geological record.

Hurst, Andrew; Scott, Anthony; Vigorito, Mario

2011-06-01

70

Robust phosphorescent platinum(II) complexes containing tetradentate O^N^C^N ligands: excimeric excited state and application in organic white-light-emitting diodes.  

PubMed

The bright white lights: A series of highly robust platinum(II) complexes supported by tetradentate O?N?C?N ligands with high emission quantum yields (0.72-0.93) and high T(d) (>400?°C) have been synthesized. Among the complexes, that shown in the figure has strong excimer emission attributed to the monomer triplet excited state with a localized structure. The application of this low band-gap material on single-dopant organic or polymer white-light-emitting diodes (WOLED) is highlighted. PMID:23239189

Kui, Steven C F; Chow, Pui Keong; Tong, Glenna So Ming; Lai, Shiu-Lun; Cheng, Gang; Kwok, Chi-Chung; Low, Kam-Hung; Ko, Man Ying; Che, Chi-Ming

2012-12-13

71

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

72

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

PubMed

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. PMID:10049933

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

1999-03-01

73

The importance of white on black: unmelanized plumage proportion predicts display complexity in birds  

Microsoft Academic Search

Animal ritualized displays have been classically viewed as behavioral characters that decrease signal ambiguity or that facilitate\\u000a the evaluation of costly exhibitions. It has been shown that their prevalence and level of complexity across species can reflect\\u000a phylogenetic relationships between them, but the adaptive function of these behavioral traits is poorly known. Here, I hypothesize\\u000a that, given that the efficacy

Ismael Galván

2008-01-01

74

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.

75

Population genetic variation, structure, and evolution in Engelmann spruce, white spruce, and their natural hybrid complex in Alberta  

Microsoft Academic Search

Genetic variation, structure, and evolution of 12 populations of putative Engelmann spruce ( Picea engelmanii Parry), white spruce (Picea glauca (Moench) Voss), and Engelmann - white spruce natural hybrids from the sympatric areas and two populations of white spruce from the allopatric areas in Alberta were examined using 23 allozyme loci coding for 13 enzymes in needles. Although most of

Om P. Rajora; Bruce P. Dancik

2000-01-01

76

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

77

Luminescence properties of Sm, Tb(Sal)3Phen complex in polyvinyl alcohol: an approach for white-light emission  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol polymer films doped with Sm,Tb(Sal)3Phen complexes have been synthesized using solution casting technique. An enhancement in absorption intensity is observed revealing the encapsulation of rare earth ions by salicylic acid (Sal)/1,10 phenanthroline (Phen) complex. Photoluminescence spectra of the co-doped samples were examined by varying the concentration of Tb3+ keeping concentration of Sm3+ ions fixed and vice-versa. It is found that the polymer samples emit a combination of blue, green and orange-red wavelengths tunable to white light when excited with 355 nm radiation. The emission spectra also show a self-quenching effect at higher concentration of Sm3+ ions. An efficient energy transfer was observed from Tb3+ : 5D4 ? Sm3+ : 4G9/2. The reason for the enhancement in fluorescence intensities of Sm3+ in the co-doped polymer sample is the intermolecular as well as the intramolecular energy transfer.

Kaur, Gagandeep; Rai, S. B.

2011-10-01

78

Identification and Characterization of Complex Bioactive Oligosaccharides in White and Red Wine by a Combination of Mass Spectrometry and Gas Chromatography  

PubMed Central

Over forty-five complex free oligosaccharides (of which several are novel) have been isolated and chemically characterized by gas chromatography and high resolution and high mass accuracy matrix-assisted laser desorption/ionization mass spectrometry (MALDI-FTICR MS) in red and white wines, Grignolino and Chardonnay, respectively. Oligosaccharides with a degree of polymerization between 3 and 14 were separated from simple monosaccharides and disaccharides by solid-phase extraction. The concentrations free oligosaccharides were over 100 mg/L in both red and white wines. The free oligosaccharides—characterized for the first time in the present study include hexose-oligosaccharides, xyloglucans and arabinogalactans, and may be the natural by-products of the degradation of cell wall polysaccharides. The coupled gas chromatography and accurate mass spectrometry approach revealed an effective method to characterize and quantify complex functional oligosaccharides in both red and white wine.

Bordiga, Matteo; Travaglia, Fabiano; Meyrand, Mickael; German, J. Bruce; Lebrilla, Carlito B.; Coisson, Jean Daniel; Arlorio, Marco; Barile, Daniela

2012-01-01

79

A Method for Preparation of Synaptonemal Complexes of Meiotic Chromosomes from Basidial Protoplasts of the White Button Mushroom Agaricus bisporus (Lange) Imbach  

Microsoft Academic Search

For the first time, preparations of synaptonemal complexes (SCs) were made from meiotic chromosomes of white button mushroom (Agaricus bisporus) basidia. It is the first experience of obtaining SC preparations of filamentous fungi from isolated meiosporangium protoplasts. Previously, only yeast SC preparations were obtained following this approach. The method includes four major stages: isolation of basidium protoplasts by treatment of

I. S. Mazheika; O. L. Kolomiets

2003-01-01

80

Plant fossils from White Island  

Microsoft Academic Search

During the D.S.I.R. expedition to White Island in January 1947, plant fossils were discovered in bedded tuffaceous sands on the south side of the island, about 17 chains north-west of Ohauora Point. On this and other coastal headlands a formation of well bedded tuffaceous sands, locally including water-worn pebbles, is exposed from high-tide level to a height of at least

C. A. Fleming

1963-01-01

81

Bioremediation of the heavy metal complex dye Isolan Dark Blue 2SGL-01 by white rot fungus Irpex lacteus.  

PubMed

The present study was conducted to evaluate the decolorization and degradation of the chromium metal complex dye Isolan Dark Blue 2SGL-01 by Irpex lacteus, a white rot lignolytic fungus. I. lacteus effectively decolorized the sulphonated reactive dye at a high concentration of 250 mg/l over a wide range of pH values of 5-9 and temperatures between 20 and 35°C. Complete (100%) decolorization occurred within 96h, and I. lacteus demonstrated resistance to the metallic dye. UV-vis spectroscopy, HPLC, GC-MS, and FT-IR analyses of the extracted metabolites confirmed that the decolorization process occurred due to degradation of the dye and not merely by adsorption. GC-MS analysis indicated the formation of 1(2H)-naphthalenone, 3,4-dihydro- and 2-naphthalenol as the main metabolite. ICP analysis demonstrated the removal of 13.49% chromium, and phytotoxicity studies using germinated seeds of Vigna radiata and Brassica juncea demonstrated the nontoxic nature of the metabolites formed during the degradation of Isolan Dark Blue 2SGL-01 dye. PMID:22071260

Kalpana, Duraisamy; Shim, Jae Hong; Oh, Byung-Taek; Senthil, Kalaiselvi; Lee, Yang Soo

2011-10-17

82

"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

83

White lies, white truth  

Microsoft Academic Search

Within and through texts written in English by white women both before and since the opening of the hearings of the Truth and Reconciliation Commission, a process of confession has been enacted. The TRC's amnesty hearings heard no submissions from English-speaking white women as perpetrators. However, the telling of stories about the self, autobiographically inflected stories – significantly stories of

Georgina Horrell

2009-01-01

84

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

2013-05-24

85

Sand pack-aided formation sand consolidation  

Microsoft Academic Search

In treating a cased and perforated well to prevent sand inflow, a resin solution from which self-curing epoxy resin is subsequently precipitated is injected into the reservoir and the perforated interval of the casing is filled with grains suspended in and permeated with the resin solution. The resin is allowed to precipitate and cure in the casing and reservoir and

Pramann

1973-01-01

86

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

87

The Eastern Pelagonian metamorphic core complex: insight from the 40Ar/39Ar dating of white micas  

NASA Astrophysics Data System (ADS)

The Pelagonian Zone in continental Greece is the westernmost unit of the Internal Hellenides that constitutes a pre-alpine crystalline block in-between two oceanic domains, the Pindos in the west and the Vardar zone in the east. We present petrographic, structural and geochronological evidence for a metamorphic core complex in eastern Pelagonian. The denuded metamorphic dome extends about 20 x 15 km with the long axis striking NNW-SSE. A shallow-dipping foliation defines the structural dome. The mineralogy of the lithologies (gneiss, impure marbles and amphibolites) show metamorphic conditions that decrease from upper-amphibolite in the core to greenschist metamorphic conditions in the flanks of the dome, reflecting structural depth and thus erosion of the dome. Aligned micas and amphiboles and elongated quartz and feldspar define a prominent lineation trending SW-NE. Asymmetric structures in the XZ finite strain plane of rocks show two regional senses of shear: (i) everywhere, top-to-the-SW sense of shear (direction: 252°±30; plunge: 8°±25) associated with strain gradients from protomylonite to ultramylonite and recumbent, isoclinal and occasional sheath folds; (ii) top-to-the-E sense of shear (direction: 88°±24; plunge: 11°±12) in narrow (0.1 to 100 m) low-angle shear zones on the eastern flanks of subdomes. The 40Ar/39Ar step-heating dating technique has been applied to micas from orthogneisses from the core to the flanks of the dome to constrain its thermal and structural evolution. The micas have been separated with acoustical shockwave produced in the SELFRAG apparatus, with the advantage to liberate morphologically intact grains. The liberated grains were sieved at different grain-sizes (between 100 and 300 ?m) depending on the micro-textures observed in thin-sections. Results show "plateau"-ages at ca. 100-120 Ma and at ca. 80 Ma. Interestingly, the 100-160 ?m fraction of white micas in a mylonitic orthogneiss yielded slightly younger ages than the 160-300 ?m fraction, arguing for neo-crystallization age during deformation of the smaller grain fraction and a more retentive apparent age with multiple diffusion domains for the larger. Micro-textures confirm an early generation of mica fish (>160 ?m) arranged between c-type shear bands representing a later generation of micas. These new ages are consistent with ages published on the southern Pelagonian, demonstrating major tectonic and metamorphic activity during early Cretaceous times.

Schenker, F. L.; Forster, M.; Burg, J.-P.

2012-04-01

88

Efficient white polymer light-emitting diodes based on a phosphorescent iridium complex and a fluorescent silole and carbazole copolymer  

NASA Astrophysics Data System (ADS)

White polymer light-emitting diodes (WPLEDs) were fabricated with blue phosphorescent iridium bis(2-(4,6-difluorophenyl)-pyridinato-N,C2?) picolinate (FIrpic) and red fluorescent silole and carbazole copolymer PCz-MPTST within a poly(N-vinylcarbazole) (PVK): 1,3-bis[(4-tert-butylphenyl)-1,3,4- oxadiazolyl] phenylene (OXD-7) host matrix. Efficient white emission consisting two emission peaks was achieved with luminous efficiency of 9.2 cd/A and CIE coordinates of (0.37, 0.40). By means of transient photoluminescence response, energy transfer among the blending components was investigated and discussed.

Xiong, Yan; Deng, Fei

2011-09-01

89

Sand, Plants and Pants  

NSDL National Science Digital Library

In this activity, learners explore how the application of nano-sized particles or coatings can change a bigger materialâs properties. Learners investigate the hydrophobic properties of plants, nano-fabric pants and magic sand.

Network, Nanoscale I.; Houston, Children'S M.

2012-06-26

90

Sand boils without earthquakes  

USGS Publications Warehouse

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

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

1993-01-01

91

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

92

Glycemic and glycosuric responses in white sturgeon ( Acipenser transmontanus) after oral administration of simple and complex carbohydrates  

Microsoft Academic Search

The ability of white sturgeon to utilize different carbohydrates was studied by using a technique combining esophageal intubation, dorsal aorta cannulation, and urinary catheterization. Seven groups of five fish each were intubated with 1 g kg?1 body weight of gelatin (sham), glucose, maltose, corn dextrin, potato dextrin, raw corn starch, or raw potato starch 48 h post-operation. The observed plasma

Dong-Fang Deng; Ståle Refstie; Silas S. O Hung

2001-01-01

93

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

94

City-swallowing Sand Dunes  

NSDL National Science Digital Library

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

Bell, Trudy E.

2007-06-19

95

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

96

Geologic implications of new zircon U-Pb ages from the White Mountain Peak Metavolcanic Complex, eastern California  

NASA Astrophysics Data System (ADS)

The NNW-trending White-Inyo Range includes intrusive and volcanic rocks on the eastern flank of the Sierran volcano-plutonic arc. The NE-striking, steeply SE-dipping Barcroft reverse fault separates folded, metamorphosed Mesozoic White Mountain Peak mafic and felsic volcanic flows, volcanogenic sedimentary rocks, and minor hypabyssal plugs on the north from folded, well-bedded Neoproterozoic-Cambrian marble and siliciclastic strata on the south. The 163 ± 2 Ma Barcroft Granodiorite rose along this fault, and thermally recrystallized its wall rocks. However, new SHRIMP-RG ages of magmatic zircons from three White Mountain Peak volcanogenic metasedimentary rocks and a metafelsite document stages of effusion at ˜115-120 Ma as well as at ˜155-170 Ma. The U-Pb data confirm the interpretation by Hanson et al. (1987) that part of the metasedimentary-metavolcanic pile was laid down after Late Jurassic intrusion of the Barcroft pluton. The Lower Cretaceous, largely volcanogenic metasedimentary section lies beneath a low-angle thrust fault, the upper plate of which includes interlayered Late Jurassic mafic and felsic metavolcanic rocks and the roughly coeval Barcroft pluton. Late Jurassic and Early Cretaceous volcanism in this sector of the Californian continental margin, combined with earlier petrologic, structural, and geochronologic studies, indicates that there was no gap in igneous activity at this latitude of the North American continental margin.

Scherer, Hannah H.; Ernst, W. G.; Brooks Hanson, R.

2008-04-01

97

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

98

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

99

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

100

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

2011-03-16

101

Efficient blue-green and white organic light-emitting diodes with a small-molecule host and cationic iridium complexes as dopants  

NASA Astrophysics Data System (ADS)

Using cationic iridium complexes as dopants and a small molecule, 9,9-bis[4-(3,6-di-tert-butylcarbazol-9-yl)phenyl]fluorene, as the host, efficient organic light-emitting diodes (OLEDs) have been fabricated from a solution process. The blue-green OLEDs achieve a peak current efficiency of 19.8 cd A-1 and a maximum brightness of 17700 cd m-2. White OLEDs have been fabricated with a peak current efficiency of 16.8 cd A-1 and Commission Internationale de l’Éclairage coordinates around (0.37, 0.44). It is suggested that cationic iridium complexes, in addition to their use in light-emitting electrochemical cells, are promising phosphorescent dopants for solution-processed small-molecule OLEDs.

He, Lei; Duan, Lian; Qiao, Juan; Zhang, Deqiang; Wang, Liduo; Qiu, Yong

2010-09-01

102

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

103

Sand Penetration Experiments  

NASA Astrophysics Data System (ADS)

In an experimental program, steel bullets and short cylinders, and tungsten alloy rods were shot into dry silica sand at 600 to 1100 m/s. The rods included finsets that were designed for aerodynamic stabilization. The fins also apparently provided trajectory stabilization within the sand as well. Time-of-arrival screens allowed measurement of velocity. Analysis of those data indicated that drag coefficients increased as projectiles slowed down. Comparison with previous data indicates there was a slight increase in drag coefficient of rods over expected values for unfinned rods; however, the net result was penetration normalized by length was as high as 40, depending on nose shape. It was found that when the velocity exceeded about 80 m/s (which is close to the speed of sound in sand) sand particles were broken down into their constituent grains, resulting in a decrease in size by about 1000. Normalized penetration is expected to scale as kinetic energy per unit area, and it was significantly higher for the rods than for the other projectiles. This is attributed to stabilization from interaction of the fins with the cavity wall.

Bless, Stephan; Berry, Don; Lawhorn, William

2009-06-01

104

Lizard locomotion on weak sand  

NASA Astrophysics Data System (ADS)

Terrestrial animal locomotion in the natural world can involve complex foot-ground interaction; for example, running on sand probes the solid and fluid behaviors of the medium. We study locomotion of desert-dwelling lizard Callisaurus draconoides (length 16 cm, mass=20 g) during rapid running on sand. To explore the role of foot-ground interaction on locomotion, we study the impact of flat disks ( 2 cm diameter, 10 grams) into a deep (800 particle diameters) bed of 250 ?m glass spheres of fixed volume fraction ? 0.59, and use a vertical flow of air (a fluidized bed) to change the material properties of the medium. A constant flow Q below the onset of bed fluidization weakens the solid: at fixed ? the penetration depth and time of a disk increases with increasing Q. We measure the average speed, foot impact depth, and foot contact time as a function of material strength. The animal maintains constant penetration time (30 msec) and high speed (1.4 m/sec) even when foot penetration depth varies as we manipulate material strength. The animals compensate for decreasing propulsion by increasing stride frequency.

Goldman, Daniel

2005-03-01

105

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

106

Sound-Producing Sand Avalanches  

Microsoft Academic Search

Sound-producing sand grains constitute one of nature's more puzzling and least understood physical phenomena. They occur naturally in two distinct types: booming and squeaking sands. Although both varieties of sand produce unexpectedly pure acoustic emissions when sheared, they diΠer in their frequency range and duration of emission, as well as the environment in which they tend to be found.

Paul Sholtz; Michael Bretz; Franco Nori

1996-01-01

107

White-electrophosphorescent devices based on copper complexes using 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole as chromaticity-tuning layer  

NASA Astrophysics Data System (ADS)

Efficient white organic light-emitting diodes based on copper complex, [Cu(bis[2-(diphenylphosphino)phenyl]ether)(6,7-dicyanodipyrido[2,2-d:2',3'-f]quinoxaline)]BF4 [Cu(I) complex], in which the white emission composed of yellow emission from Cu(I) complex doped 4,4'-N,N'-dicarbazole-biphenyl (CBP) layer and blue emission from N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-benzidine)-4,4'-diamine layer, were fabricated. A thin 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole (Bu-PBD) layer sandwiched between the two emission layers acts as a chromaticity-tuning layer. The white device with 10 nm, 2 wt % Cu(I) complex doped CBP layer and 2 nm Bu-PBD layer shows CIE coordinates of (0.33,0.36) at applied bias of 10 V, a maximum luminance of 2466 cd/m2, and a maximum current efficiency of 6.76 cd/A, corresponding to the power efficiency of 3.85 lm/W. The efficient white emission is attributed to the simultaneous exciton formation in both emission layer. The working mechanism of the thin Bu-PBD layer for achieving white emission was also discussed.

Su, Zisheng; Che, Guangbo; Li, Wenlian; Su, Wenming; Li, Mingtao; Chu, Bei; Li, Bin; Zhang, Zhiqiang; Hu, Zhizhi

2006-05-01

108

PROCESSING OF MONAZITE SAND  

DOEpatents

A process for the recovery of thorium, uranium, and rare earths from monazite sands is presented. The sands are first digested and dissolved in concentrated NaOH, and the solution is then diluted causing precipitation of uranium, thorium and rare earth hydroxides. The precipitate is collected and dissolved in HCl, and the pH of this solution is adjusted to about 6, precipitating the hydroxides of thorium and uranium but leaving the rare earths in solution. The rare earths are then separated from the solution by precipitation at a still higher pH. The thorium and uranium containing precipitate is redissolved in HNO/sub 3/ and the two elements are separated by extraction into tributyl phosphate and back extraction with a weakly acidic solution to remove the thorium.

Calkins, G.D.; Bohlmann, E.G.

1957-12-01

109

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

110

Intranasal Inoculation of White-Tailed Deer (Odocoileus virginianus) with Lyophilized Chronic Wasting Disease Prion Particulate Complexed to Montmorillonite Clay  

PubMed Central

Chronic wasting disease (CWD), the only known prion disease endemic in wildlife, is a persistent problem in both wild and captive North American cervid populations. This disease continues to spread and cases are found in new areas each year. Indirect transmission can occur via the environment and is thought to occur by the oral and/or intranasal route. Oral transmission has been experimentally demonstrated and although intranasal transmission has been postulated, it has not been tested in a natural host until recently. Prions have been shown to adsorb strongly to clay particles and upon oral inoculation the prion/clay combination exhibits increased infectivity in rodent models. Deer and elk undoubtedly and chronically inhale dust particles routinely while living in the landscape while foraging and rutting. We therefore hypothesized that dust represents a viable vehicle for intranasal CWD prion exposure. To test this hypothesis, CWD-positive brain homogenate was mixed with montmorillonite clay (Mte), lyophilized, pulverized and inoculated intranasally into white-tailed deer once a week for 6 weeks. Deer were euthanized at 95, 105, 120 and 175 days post final inoculation and tissues examined for CWD-associated prion proteins by immunohistochemistry. Our results demonstrate that CWD can be efficiently transmitted utilizing Mte particles as a prion carrier and intranasal exposure.

Nichols, Tracy A.; Spraker, Terry R.; Rigg, Tara D.; Meyerett-Reid, Crystal; Hoover, Clare; Michel, Brady; Bian, Jifeng; Hoover, Edward; Gidlewski, Thomas; Balachandran, Aru; O'Rourke, Katherine; Telling, Glenn C.; Bowen, Richard

2013-01-01

111

Booming Sand Dunes  

NASA Astrophysics Data System (ADS)

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

Vriend, Nathalie

112

The complex emission-line structure in the magnetic white dwarf binary 2A 0311-227 /EF Eridani/  

NASA Astrophysics Data System (ADS)

All phases of the 81 minute orbit of the magnetic X-ray binary 2A 0311-227 are covered in a series of single-trailed spectrograms of duration 25 minutes each, and resolution 2 A. Superposition of the data shows that an extremely complex line-structure and variation exist, which are phase-locked with the orbit. Previous measures by the authors are confirmed. An improved value for the orbital period is derived by comparing observations separated by 9 months. The appearance and velocities of the lines are shown. At present, no quantitative models exist to describe the complex gas streaming. Some evidence is given that at least two regions (poles), separated by less than 180 deg, of different temperature, are present.

Hutchings, J. B.; Fisher, W. A.; Cowley, A. P.; Crampton, D.; Liller, M. H.

1982-01-01

113

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

114

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

115

Well sand packing prevention method  

SciTech Connect

A method is described of preventing sand packing in a producing well completed in a zone adjacent a hydrocarbon-bearing subterranean formation, comprising the steps of: producing fluid from the hydrocarbon-bearing formation, the fluid comprising an aqueous phase and a hydrocarbon phase; and, simultaneously with the fluid production, injecting a sand control agent into the well adjacent the production zone at a rate to obtain a wellhead concentration of the sand control agent in the aqueous phase of the fluid of from about 10 to about 1000 ppm active. The sand control agent is a quaternized acylated condensed alkanolamine.

Chakrabarty, T.; Thomas, R.

1986-11-18

116

Apparatus for processing bituminous sands  

Microsoft Academic Search

An apparatus for processing bituminous sands to recover petroleum is provided. The apparatus is preferably a multicell structure, principal cells of which include bottom stirrer zones and upper quiet zones separated from the stirrer zones by baffles. Continuous through-plant feed is provided for the plant structure by partially processed sands being urged into subsequent cells for continued processing. An oil

Brimhall

1971-01-01

117

Steppin' out of Whiteness  

Microsoft Academic Search

Current paradigms of identity, especially those found in Whiteness Studies, do not sufficiently explain the complex interaction and intersection of race, culture, and identity. Drawing on two years of extended fieldwork in the Steppin' dance scene in Chicago, I extend Bourdieu's theory of practice, particularly the role of the body in culture, to the study of race and identity. This

Black Hawk Hancock

2005-01-01

118

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

119

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

120

Committed White Male Teachers and Identifications: Toward Creative Identifications and a "Second Wave" of White Identity Studies  

ERIC Educational Resources Information Center

|Committed White male teachers of inner-city students seeks to supersede previous research on White teacher and other White identities by narrating respondents' "creative identifications" and initiating a "second wave" of White identity studies. This research reflection articulates complex, viable, and creative White identities, reconceptualized…

Jupp, James C.; Slattery, G. Patrick, Jr.

2010-01-01

121

Memo of Understanding Between AEC and White Sands Proving Ground  

Microsoft Academic Search

AEC was given exclusive use and occupancy of the assembly building and the appurtenant structures which had bee constructed with AEC funds. It was to furnish fire protection and maintenance of the facilities.

C. L. Tyler; G. G. Eddy; H. G. Froelich

1952-01-01

122

White Sands Missile Range 2011 Drinking Water Quality Report.  

National Technical Information Service (NTIS)

The table below lists the results of the most recent drinking water tests. During calendar year 2011, WSMR conducted tests for volatile organic chemicals (VOCs), synthetic organic chemicals (SOCs), inorganic chemicals (IOCs), disinfection by-products, and...

2012-01-01

123

Development of a Severe Sand-dust Storm Model and its Application to Northwest China  

Microsoft Academic Search

A very strong sand-dust storm occurred on 5 May, 1993 in Northwest China. In order to give a detailed description of the evolution of a mesoscale system along with the heavy sand-dust storm, a complex model including improved physicalprocesses and a radiation parameterization scheme was developedbased on a simulation model. The improved model introduced a sand-dust transport equation as well

Xiao-Ling Zhang; Linsheng Cheng; Yong-Seung Chung

2003-01-01

124

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

Microsoft Academic Search

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

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

2012-01-01

125

IOCC monograph series: tar sands  

SciTech Connect

This is a collection of important papers published on tar sand resources and technologies. It includes nineteen previously published significant technical reports which describe tar sand resources and related technologies. The reports are primarily descriptions of the United States resource and efforts to develop that resource; however, several reports describing Canadian tar sand activities are included because they are the only available publications dealing with the respective technology areas. The republished reports represent the following categories: World Resource Overview; US Resource Overview (Utah, California, Kentucky, Kansas, Missouri, Oklahoma); Extraction Technologies (including in-situ and mining-and-plant-extraction); Field Trials and Commercialization; and Environmental Assessment. (DP)

Ball, D.; Marchant, L.C.; Goldburg, A. (eds.)

1982-01-01

126

Process to separate bituminous material from sand (tar sands)  

SciTech Connect

Bituminous sand such as oil sand or tar sand is mixed with a halogenated organic solvent which has a density greater than that of water at the same temperature. The slurry is continuously transferred to a conveyor system which is at least partially submerged in water, with the slurry being fed onto the portion of the conveyor which is submerged. As the sands move through the water on the conveyor, the organic solvent containing the bituminous material separates from the sand and forms a separate phase beneath the water. The sands ultimately move upwardly on the conveyor through the surface of the water. The organic phase is removed from beneath the water surface and the halogenated solvent is flashed therefrom in a flash evaporator chamber. Solvent vapors are withdrawn from the evaporator chamber by a compressor, and the compressed vapors are introduced into a condenser chamber. A heat exchange medium is continuously circulated between the condenser and evaporator chambers, with heat being transferred from the heat exchange medium in the evaporator and back to the heat exchange medium in the condenser. Bituminous organic material is withdrawn from the evaporator chamber and condensed solvent is recovered from the condenser. Preferably, the heat exchange means comprises a plurality of heat pipes, with mutually respective end portions of the heat pipes extending into the condenser chamber and the other end portions extending into the evaporator chamber.

Gagon, H.W.

1982-08-03

127

CKI and CKII mediate the FREQUENCY-dependent phosphorylation of the WHITE COLLAR complex to close the Neurospora circadian negative feedback loop  

PubMed Central

The eukaryotic circadian oscillators consist of circadian negative feedback loops. In Neurospora, it was proposed that the FREQUENCY (FRQ) protein promotes the phosphorylation of the WHITE COLLAR (WC) complex, thus inhibiting its activity. The kinase(s) involved in this process is not known. In this study, we show that the disruption of the interaction between FRQ and CK-1a (a casein kinase I homolog) results in the hypophosphorylation of FRQ, WC-1, and WC-2. In the ck-1aL strain, a knock-in mutant that carries a mutation equivalent to that of the Drosophila dbtL mutation, FRQ, WC-1, and WC-2 are hypophosphorylated. The mutant also exhibits ~32 h circadian rhythms due to the increase of FRQ stability and the significant delay of FRQ progressive phosphorylation. In addition, the levels of WC-1 and WC-2 are low in the ck-1aL strain, indicating that CK-1a is also important for the circadian positive feedback loops. In spite of its low accumulation in the ck-1aL strain, the hypophosphorylated WCC efficiently binds to the C-box within the frq promoter, presumably because it cannot be inactivated through FRQ-mediated phosphorylation. Furthermore, WC-1 and WC-2 are also hypophosphorylated in the ckaRIP strain, which carries the disruption of the catalytic subunit of casein kinase II. In the ckaRIP strain, WCC binding to the C-box is constantly high and cannot be inhibited by FRQ despite high FRQ levels, resulting in high levels of frq RNA. Together, these results suggest that CKI and CKII, in addition to being the FRQ kinases, mediate the FRQ-dependent phosphorylation of WCs, which inhibit their activity and close the circadian negative feedback loop.

He, Qun; Cha, Joonseok; He, Qiyang; Lee, Heng-Chi; Yang, Yuhong; Liu, Yi

2006-01-01

128

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

129

Studies of Phlebotomine Sand Flies.  

National Technical Information Service (NTIS)

A preliminary key to the phlebotomine sand flies of Kenya was prepared as an aid to identification. The need for fresh material readily apparent. Further progress was made on illustrating important features of New World species, necessary for inclusion in...

D. G. Young

1980-01-01

130

METHOD OF PROCESSING MONAZITE SAND  

DOEpatents

A method is given for the pretreatment of monazite sand with sodium hydroxide. When momazite sand is reacted with sodium hydroxide, the thorium, uranium, and rare earths are converted to water-insoluble hydrous oxides; but in the case of uranium, the precipitate compound may at least partly consist of a slightly soluble uranate. According to the patent, monazite sand is treated with an excess of aqueous sodium hydroxide solution, and the insoluble compounds of thorium, uranium, and the rare earths are separated from the aqueous solution. This solution is then concentrated causing sodium phosphate to crystallize out. The crystals are removed from the remaining solution, and the solution is recycled for reaction with a mew supply of momazite sand.

Calkins, G.D.

1957-10-29

131

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

PubMed Central

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 and their interactions. We attempted to characterize the genetic architecture of ABI by examining the main and interactive effects of individual single nucleotide polymorphisms (SNPs) and conventional risk factors. Methods We applied linear regression analysis to investigate the association of 435 SNPs in 112 positional and biological candidate genes with ABI and related physiological and biochemical traits in 1046 non-Hispanic white, hypertensive participants from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. The main effects of each SNP, as well as SNP-covariate and SNP-SNP interactions, were assessed to investigate how they contribute to the inter-individual variation in ABI. Multivariable linear regression models were then used to assess the joint contributions of the top SNP associations and interactions to ABI after adjustment for covariates. We reduced the chance of false positives by 1) correcting for multiple testing using the false discovery rate, 2) internal replication, and 3) four-fold cross-validation. Results When the results from these three procedures were combined, only two SNP main effects in NOS3, three SNP-covariate interactions (ADRB2 Gly 16 – lipoprotein(a) and SLC4A5 – diabetes interactions), and 25 SNP-SNP interactions (involving SNPs from 29 different genes) were significant, replicated, and cross-validated. Combining the top SNPs, risk factors, and their interactions into a model explained nearly 18% of variation in ABI in the sample. SNPs in six genes (ADD2, ATP6V1B1, PRKAR2B, SLC17A2, SLC22A3, and TGFB3) were also influencing triglycerides, C-reactive protein, homocysteine, and lipoprotein(a) levels. Conclusion We found that candidate gene SNP main effects, SNP-covariate and SNP-SNP interactions contribute to the inter-individual variation in ABI, a marker of PAD. Our findings underscore the importance of conducting systematic investigations that consider context-dependent frameworks for developing a deeper understanding of the multidimensional genetic and environmental factors that contribute to complex diseases.

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

2008-01-01

132

Modern Graywacke-Type Sands.  

PubMed

A preliminary study of more than 100 deep-sea cores from abyssal plains has revealed two examples of recent muddy sands of the graywacke type which, together with the microcrystalline matrix, form a bimodal-size distribution sands have a well-sorted framework of quartz, feldspar, and rock fragments which, together with the microcrystalline matrix, form a bimodal-size distribution that is also typical of ancient graywackes. The matrix is considered to be primary. PMID:17775982

Hollister, C D; Heezen, B C

1964-12-18

133

Aeolian sand transport: a wind tunnel model  

Microsoft Academic Search

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

Zhibao Dong; Xiaoping Liu; Hongtao Wang; Xunming Wang

2003-01-01

134

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

135

Tensile Strength Characteristics of Unsaturated Sands  

Microsoft Academic Search

Tensile strength characteristics of unsaturated sands are examined through a combined theoretical and experimental study. The characteristics of tensile strength in all three water retention regimes of pendular, funicular, and capillary are examined. A simple direct tensile strength apparatus is employed to determine tensile strength for sands with a broad range of particle sizes from silty sand to fine sand

Ning Lu; Bailin Wu

2007-01-01

136

A modified probability distribution of ejection state of sand grains in equilibrium aeolian sand transport  

Microsoft Academic Search

Equilibrium sand transport is simulated by stochastic Lagrange particle tracking method combined with probability distribution of initial ejection state of sand grains. Comparing the simulated vertical profile of horizontal sand mass flux and the experimental profiles, a modified exponential distribution is suggested to describe ejection speed and angle of sand grains in equilibrium sand transport. This modified exponential distribution is

Mao Xing; Liejin Guo

2004-01-01

137

Drawing Lines in the Sand - Co-speech Graphics, Gesture and Sign in Arabic Sand Drawing Narratives  

Microsoft Academic Search

Speakers of the Arandic languages in Central Australia use a range of semiotic systems, including everyday language, spoken auxiliary languages, the language of songs, sign language and the symbolic or graphic conventions used in sand-drawing and in various forms of Aboriginal art. Spontaneous gesture is also part of this complexity, and in a communicative event various of these systems can

Jenny Green

138

MATHEMATICS WRITTEN IN SAND  

Microsoft Academic Search

ABSTRACT: Simplicity is a Virtue; yet we continue to cram ever more complicated circuits ever more densely into silicon chips, hoping all the while that their internal complexity will promote simplicity of use. This paper exhibits how well that hope has been fulfilled by several inexpensive devices widely used nowadays for numerical computation. One of them is the Hewlett-Packard hp-15C

W. Kahan

1983-01-01

139

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

140

Sedimentology of Upper Cretaceous Coffee sands in north-central Mississippi  

Microsoft Academic Search

The Upper Cretaceous Coffee Group within the Desha basin of Mississippi is composed of two major lithologies, a light to dark marlstone and a series of white, fine to medium-grained siltstones and sandstones. The two source areas for the sands are the Sharkey platform to the south and the southern Appalachians. The presence of hydrocarbons has been described at the

Webb

1984-01-01

141

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

142

Sand fracturing vs frac acidizing  

SciTech Connect

Production histories of two wells were used to compare performances of fracture acidizing and sand fracturing treatments in a study that compared stimulation results of the Ratcliffe Formation in the Williston Basin. The study concluded that with a computer model and production history, fracture geometry may be calculated through curve matching. Use of this method may be helpful in the design of future stimulation jobs. Results of this study indicate greater well production rates and greater cumulative production from sand fracturing than equivalent cost fracture acidizing treatment.

Bailey, D.E.

1984-02-01

143

Rethinking white resistance: exploring the discursive practices and psychical negotiations of ‘whiteness’ in feminist, anti?racist education  

Microsoft Academic Search

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 discourses of whiteness, have been neglected in pedagogical research, diminishing the potential for understanding processes

Jessica Ringrose

2007-01-01

144

Direct and Indirect Effects of Case Complexity, Guilty Pleas, and Offender Characteristics on Sentencing for Offenders Convicted of a White-Collar Offense Prior to Sentencing Guidelines  

Microsoft Academic Search

Previous research on the punishment of offenders convicted of a white-collar offense estimated models that specify only direct effects of defendant characteristics, offense-related variables, and guilty pleas on sentence severity. Drawing from conflict or labeling theories, much of this research focused on the effects of offender's socioeconomic status on sentence outcomes. Findings from this research are inconsistent about the relationship

Celesta A. Albonetti

1998-01-01

145

To Break Away or Strengthen Ties to Home: A Complex Issue for African American College Students Attending a Predominantly White Institution  

Microsoft Academic Search

African American students and former students from a predominantly white institution (PWI) were interviewed to understand their perceptions regarding the impact of their families on their academic achievement and persistence. The characteristics of families that students perceived to support and hinder their academic success at college are described along with implications for improving African American college student retention theory and

Douglas Guiffrida

2005-01-01

146

Numerical simulation of saltating particles in atmospheric boundary layer over flat bed and sand ripples  

NASA Astrophysics Data System (ADS)

In this work, we numerically simulated the saltating particles in a turbulent boundary layer over flat bed and sand ripples. By using natural sand grains in a wind tunnel, we obtained the initial conditions for the simulation and also verified the correctness of the numerical model. We carefully analyzed the numerically simulated saltating particle movement over the two sand beds, and we found the following. (1) The aeolian sand transport is a dynamic equilibrium process on both sand beds, and it took longer to reach equilibration on the sand ripples than on the flat bed. (2) According to the mass flux profile at the trough of the sand ripples, there is a maximum mass flux at about 4 cm height in the leeward section. The mass flux increases with height below 4 cm and decreases with height above 4 cm. (3) The wind profile near the surface is modified by saltating particles on the two different sand beds, and the flow field characteristics of the sand ripples are more complex than that of the flat bed.

Tong, Ding; Huang, Ning

2012-08-01

147

Holocene deposits of reservoir-quality sand along the Central South Carolina coastline  

SciTech Connect

The Holocene coastal sand deposits of the central South Carolina coastline were investigated to estimate volumes of reservoir-quality (RQ) sediments. These sand bodies, which vary considerably in size, thickness, shape, and continuity, were deposited in a variety of depositional settings including barrier islands, ebb-tidal deltas, exposed sand flats, tidal sand ridges, and tidal point bars. To identify the RQ sediment for each sand-body type, a conservative mud cutoff value of 15% was chosen. Average thickness values ranged from 6 m for barrier island deposits to 15 m for ebb-tidal deltas. Of the six most significant RQ sand depositional environments on the central portion of the South Carolina coast, ebb-tidal delta complexes accounted for 77% of all RQ sediments. This dominance of the ebb-tidal delta deposits is attributed to the relatively large tidal range in the area (up to 3 m) and to the presence of a number of large, incised alluvial valleys, which are host to estuarine complexes with large tidal prisms. If the Holocene sand deposits along the central 115 km of the South Carolina coast were preserved in the rock record, a total of 1.3 X 10{sup 6} ac-ft of RQ sands would be present, a significant amount considering the short time interval of approximately 5000 yr.

Sexton, W.J. [Athena Technologies, Inc., Columbia, SC (United States); Hayes, M.O. [Research Planning, Inc., Columbia, SC (United States)

1996-06-01

148

Growth of nestling Sand Martins  

Microsoft Academic Search

Nestling Sand Martins are heaviest at 12 days old (on average), but then lose weight. Rapid early growth of the tarsi enables nestlings to move along the burrow towards incoming parents. The nestling period averages 22.3 days, and the young are dependent on their parents for a further 4–5 days after fledging.

A. K. Turner; D. M. Bryant

1979-01-01

149

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

150

Alberta Oil Sands Development Conflict  

Microsoft Academic Search

A systems approach to integrative adaptive management of brownfields on Alberta's oil sands development sites is presented. In particular, the Graph Model for Conflict Resolution (GMCR) is utilized to understand underlying development conflicts among stakeholders, which arise due to competing economic, environmental and societal objectives. The conflict model provides a formalized hypothesis-testing platform for determining responsible policies, which are those

Michele Heng; Keith W. Hipel; Liping Fang

2009-01-01

151

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

152

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

153

Behavior of Plastic Sand Confinement Grids.  

National Technical Information Service (NTIS)

The concept of improving the load carrying ability of unbound aggregates, particularly sand, by lateral confinement has been investigated for some time. Extensive full-scale testing of the trafficability of confined beach sand pavement layers has been car...

1986-01-01

154

Soggy-sand electrolytes: status and perspectives.  

PubMed

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

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

2013-10-01

155

Regeneration of sand waves after dredging  

Microsoft Academic Search

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

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

2002-01-01

156

Adsorption of dyes on Sahara desert sand  

Microsoft Academic Search

Sahara desert sand (SaDeS) was employed as a mineral sorbent for retaining organic dyes from aqueous solutions. Natural sand has demonstrated a strong affinity for organic dyes but significantly lost its adsorption capacity when it was washed with water. Therefore, characterization of both natural and water washed sand was performed by XRD, BET, SEM and FTIR techniques. It was found

Canan Varlikli; Vlasoula Bekiari; Mahmut Kus; Numan Boduroglu; Ilker Oner; Panagiotis Lianos; Gerasimos Lyberatos; Siddik Icli

2009-01-01

157

Erosion of mud\\/sand mixtures  

Microsoft Academic Search

The prediction of sediment erosion is an important issue in coastal engineering projects. There are methods for predicting the erosion of cohesive sediment (mud) and non-cohesive sediment (sand), but there are presently no relationships for mixed sediments. However, natural sediments rarely consist of only mud or sand and the erosional properties of combined mud and sand sediments are required so

Helen Mitchener; Hilde Torfs

1996-01-01

158

Fluidized bed retorting of tar sands  

Microsoft Academic Search

Raw tar sand is treated in a fluidized bed reactor means wherein the raw tar sands are fed into an area below the top of the bed. The bitumen is converted in the process in a reducing atmosphere including steam to produce hot coked sand and hot off-gases. Off-gases from the reactor means pass through a heat exchanger means to

P. H. II

1978-01-01

159

Sand reinforced with shredded waste tires  

Microsoft Academic Search

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

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

1996-01-01

160

Vertical profiles of aeolian sand mass flux  

Microsoft Academic Search

Vertical profiles of the horizontal mass flux of blown sand are investigated experimentally using a passive vertical array in a wind tunnel. Considering lower sampling efficiency of the sand trap in the near-bed region, this investigation is complemented by the measurements of the longitudinal profiles of mass flux made using a horizontal sand trap. The experiments were conducted with two

J. R Ni; Z. S Li; C Mendoza

2003-01-01

161

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

162

Sand and Water Table Buying Guide.  

ERIC Educational Resources Information Center

Discusses the importance of sand and water play for young children. Provides a partial list of materials and equipment used to provide sensory experiences at sand and water tables. Offers a buying guide listing manufacturers of sand and water tables, product descriptions, and ordering information. (DR)

Morris, Susan

1990-01-01

163

Project CHECO Southeast Asia Report. Igloo White (Initial Phase).  

National Technical Information Service (NTIS)

Exceedingly costly and complex, the MUSCLE SHOALS program (changed to IGLOO WHITE in June 1968) required dynamic planning of many agencies of the Department of Defense. 'IGLOO WHITE (Initial Phase)' provides an overview of its contribution to the interdic...

J. C. Gatlin

1968-01-01

164

Induced polarization of clay-sand mixtures. Experiments and modelling.  

NASA Astrophysics Data System (ADS)

The complex conductivity of saturated unconsolidated sand-clay mixtures was experimentally investigated using two types of clay minerals, kaolinite and smectite (mainly Na-Montmorillonite) in the frequency range 1.4 mHz - 12 kHz. The experiments were performed with various clay contents (1, 5, 20, and 100 % in volume of the sand-clay mixture) and salinities (distilled water, 0.1 g/L, 1 g/L, and 10 g/L NaCl solution). Induced polarization measurements were performed with a cylindrical four-electrode sample-holder associated with a SIP-Fuchs II impedance meter and non-polarizing Cu/CuSO4 electrodes. The results illustrate the strong impact of the CEC of the clay minerals upon the complex conductivity. The quadrature conductivity increases steadily with the clay content. We observe that the dependence on frequency of the quadrature conductivity of sand-kaolinite mixtures is more important than for sand-bentonite mixtures. For both types of clay, the quadrature conductivity seems to be fairly independent on the pore fluid salinity except at very low clay contents. The experimental data show good agreement with predicted values given by our SIP model. This complex conductivity model considers the electrochemical polarization of the Stern layer coating the clay particles and the Maxwell-Wagner polarization. We use the differential effective medium theory to calculate the complex conductivity of the porous medium constituted of the grains and the electrolyte. The SIP model includes also the effect of the grain size distribution upon the complex conductivity spectra.

Okay, G.; Leroy, P.

2012-04-01

165

Unveiling White Privilege.  

ERIC Educational Resources Information Center

Racism, discrimination, and prejudice are typically viewed from the perspective of the disadvantaged ethnic minority, but another approach is to address the advantages of whites. There is one culture that is usually invisible to whites, and that is "whiteness." To grow up white is to be the focal point from which others differ. Whites grapple with…

Pappas, Georgia

1995-01-01

166

Happy Birthday White House!  

ERIC Educational Resources Information Center

|An integrated elementary teaching package offers interesting facts about presidents and the White House. Cross-curricular activities focus on architecture, presidential birthplaces, portraits, communications, science, technology, touring the White House, children in the White House, a day in the life of the White House, and a White House birthday…

Dillon, Doris; And Others

1992-01-01

167

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

Microsoft Academic Search

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

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

2011-01-01

168

Wind initiation thresholds of the moistened sands  

NASA Astrophysics Data System (ADS)

The widely accepted Bagnold-type function for calculating threshold wind velocity or shear velocity was developed for dry sands, but surface moisture is an extremely important variable controlling the entrainment process of sands by wind because the tensile force between the water molecules and sand grains produces cohesion. Here we report detailed wind tunnel experimental results on the threshold shear velocity of moistened sand of different sizes. The results show that relative threshold shear velocity, which is the ratio of threshold shear velocity of sand in the moistened state to that in the dry state, is better related to moisture content than threshold shear velocity itself. Function, modified after the Bagnold equation has been developed to estimate the threshold shear velocities of moistened sands. For a given grain size, the threshold shear velocity is proportional to (1 + KM)1/2, where, M is the moisture content, and K is a coefficient depending on grain size.

Dong, Zhibao; Liu, Xiaoping; Wang, Xunming

2002-06-01

169

Sand banks of finite amplitude  

NASA Astrophysics Data System (ADS)

The process which leads to the appearance of sand banks in shallow seas is investigated by studying the growth of small-amplitude perturbations of the sea bottom, forced by oscillatory tidal currents. Since the analysis of field data carried out by Dyer and Huntley (1999) suggests that sand banks are likely to occur where the tidal ellipse is circular or characterized by a low ellipticity, attention is focused on small values of ?, where e is the ratio between minor and major axes of the tidal ellipse. The linear analysis, which considers perturbations of small (strictly infinitesimal) amplitude, shows the existence of a critical value rC of the Keulegan-Carpenter number r of the tide (r = U0*/(h0*?*), U0* and ?* being the amplitude and angular frequency of the velocity oscillations induced by the tide propagation and h0* being the averaged water depth) such that for r smaller than rC the flat bottom configuration is stable, while for r larger than rC the sand banks start to appear. Close to the critical condition, the wavelength of the most unstable mode turns out to be finite. Then a weakly nonlinear analysis is developed which allows the evaluation of the equilibrium amplitude of the bottom forms when the parameter r is close to its critical value. The configuration of the sea bottom, when the bottom forms attain their equilibrium, is characterized by the presence of long ridges, almost parallel to the main axis of the tidal ellipse, with crest-to-crest distances similar to those observed during field surveys. The crests of the bottom forms turn out to be flat, and the extensive shallow waters at the crests are compensated by deep troughs between the ridges.

Tambroni, N.; Blondeaux, P.

2008-10-01

170

Episodic dynamics of a sand wave field  

Microsoft Academic Search

The morphodynamics of a sand wave field in a flood-dominant channel inside Moriches Inlet was monitored for eight weeks during the summer of 2005. Bathymetric data show sand waves on average are 15 m long and 39 cm high with shallow slip faces. The sand waves remained stationary over the eight-week study. The maximum peak current speeds recorded during this study only

Shelley J. Whitmeyer; Duncan M. FitzGerald

2008-01-01

171

Sand Stabilization with Hydroxy Aluminum Solutions  

Microsoft Academic Search

In many oil-producing reservoirs, sand and other fine-grained rock materials migrate into wells. This influx may decrease oil production by plugging gravel packs, eroding well equipment or completely sanding up wells. A procedure is described for treating such formations with hydroxy-aluminum to stabilize clay minerals and thereby prevent sand and silt production. Hydroxy-aluminum is a relatively inexpensive and commercially available

M. G. Reed; Claude Coppel

1972-01-01

172

Pyrolysis of Arroyo Grande tar sand and tar sand/oil mixtures.  

National Technical Information Service (NTIS)

Pyrolysis experiments have been performed on Arroyo Grande tar sand and on mixtures of tar sand and SAE 50 oil. Isothermal and nonisothermal tests were performed on a Du Pont model 950 thermogravimetric analyzer (TGA), and larger scale isothermal experime...

T. F. Turner B. E. Thomas L. G. Nickerson

1989-01-01

173

[Model experiments on breathing under sand].  

PubMed

Remarkable autopsy findings in persons who had suffocated as a result of closure of the mouth and nose by sand (without the body being buried) induced us to investigate some aspects of this situation by means of a simple experiment. A barrel (diameter 36.7 cm) with a mouthpiece in the bottom was filled with sand to a depth of 15, 30, 60, or 90 cm. The subject tried to breathe as long as possible through the sand, while the amount of sand inspired was measured. Pressure and volume of the breath, as well as the O2 and CO2 content were also measured. A respiratory volume of up to 31 was possible, even when the depth was 90 cm. After about 1 min in all trials, the subject's shortness of breath forced us to stop the experiment. Measurement of O2 and CO2 concentrations proved that respiratory volume in and out of the sand shifts to atmospheric air without gas exchange, even when the sand depth is 15 cm. Sand aspiration depended on the moisture of the material: when the sand was dry, it was impossible to avoid aspiration. However, even a water content of only 5% prevented aspiration, although the sand seemed to be nearly dry. PMID:3927604

Maxeiner, H; Haenel, F

1985-01-01

174

Minerals yearbook, 1988: Industrial sand and gravel  

SciTech Connect

Production of industrial sand and gravel in 1988 increased to 28.5 million short tons, about a 2% increase over that of 1987, but remained 15% below the record-high production level of 1979. The production increase was due in part to the addition of new operations in California and Tennessee. Imports of industrial sand and gravel decreased about 59% in quantity, but the associated value increased 79%. Exports of industrial sand and gravel increased about 40% in quantity with a slight increase in average value per ton. Domestic apparent consumption of industrial sand and gravel in 1988 was 27.5 million tons.

Bolen, W.P.

1988-01-01

175

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

2011-06-12

176

Offshore sand resources for coastal erosion control in Louisiana  

SciTech Connect

An inventory of existing geophysical data supplemented by more than 15,000 km of high-resolution seismic profiles and 400 vibracores collected cooperatively by the Louisiana Geological Survey and US Geological Survey since 1981 indicates that a wide range of aggregate minerals occurs on the continental shelf in a variety of depositional settings. The distribution of these deposits is controlled by the geometry of the preexisting fluvial and deltaic channel systems and the stratigraphic signature of the Holocene Transgression across these features. The geology of coastal and offshore Louisiana is tied to the depositional history of the Mississippi River. Offshore of the delta plain, five types of aggregate sources can be identified: inner shelf shoals, submerged barrier islands, tidal inlets, distributary channels, and barrier platforms. This paper describes the geology of offshore Louisiana, the available geophysical data sets, and the distribution of aggregate mineral resources. On the continental shelf of the Mississippi River delta plain, two extensive seismic survey grids have been developed by the Louisiana Geological Survey and US Geological Survey. The most prospective resources found are the huge sand bodies of Ship Shoal and associated distributaries, Cat Island Pass tidal channels and associated tidal deltas, and Barataria Pass/Grand Terre tidal channels and associated tidal deltas. East of the mouth of the Mississippi River are the Chandeleur Islands, where LGS identified seven major sand resource targets, truncated barrier-spit and tidal inlet deposits, submerged beach ridges, and distributaries associated with abandoned St. Bernard delta complexes. Abundant sand resources can be found in offshore Louisiana. Many of the sand bodies contain heavy minerals, but their concentration and distribution is unknown. Other potential sand resources not yet adequately explored include Sabine Bank, the Outer Shoal, and the St. Bernard shoal.

Ramsey, K.E.; Penland, S.; McBride, R.A. (Louisiana Geological Survey, Baton Rouge (USA)); Suter, J.R. (Exxon Production Research, Houston, TX (USA)); Williams, J. (Geological Survey, Reston, VA (USA))

1990-09-01

177

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

178

Fecal indicators in sand, sand contact, and risk of enteric illness among beach-goers  

EPA Science Inventory

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 2 recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days...

179

[Spatial distribution patterns of dry sand layer on windward slope of dunes in Horqin Sand Land].  

PubMed

An observation was conducted on the thickness of dry sand layer on the windward slope of mobile and fixed dunes in west Horqin Sand Land, with the spatial distribution of the dry sand layer analyzed. Most of the dry sand layer had a thickness of 5-15 cm, and 92.0% and 98.6% of the mobile and fixed dunes had the dry sand layer with this thickness, respectively. Sand-fixing plants affected the thickness and the spatial distribution of the dry sand layer. There was an obvious spatial difference in the thickness of the dry sand layer on mobile dunes, being much thicker in the upper west areas while much thinner in the lower east areas. The thickness of the dry sand layer varied from 0 to 40 cm, with an average of 9.58 +/- 3.95 cm, and the CV was 41%. The variogram of the spatial distribution of dry sand layer on mobile dunes was expressed as spherical model, with a moderate spatial correlation. In contrast, the thickness of dry sand layer on fixed dunes showed obvious homogeneity, and had less spatial difference. The thickness of the dry sand layer ranged from 0 to 20 cm, with an average of 10.91 +/- 1.70 cm, and the CV was only 16%. PMID:22803448

Zong, Qin; Lamusa, A; Luo, Yong-Ming; Niu, Cun-Yang; Chen, Xue-Feng; Wang, Hai-Yang

2012-04-01

180

An Evi1-C/EBP? Complex Controls Peroxisome Proliferator-Activated Receptor ?2 Gene Expression To Initiate White Fat Cell Differentiation  

PubMed Central

Fibroblastic preadipocyte cells are recruited to differentiate into new adipocytes during the formation and hyperplastic growth of white adipose tissue. Peroxisome proliferator-activated receptor ? (PPAR?), the master regulator of adipogenesis, is expressed at low levels in preadipocytes, and its levels increase dramatically and rapidly during the differentiation process. However, the mechanisms controlling the dynamic and selective expression of PPAR? in the adipocyte lineage remain largely unknown. We show here that the zinc finger protein Evi1 increases in preadipocytes at the onset of differentiation prior to increases in PPAR? levels. Evi1 expression converts nonadipogenic cells into adipocytes via an increase in the predifferentiation levels of PPAR?2, the adipose-selective isoform of PPAR?. Conversely, loss of Evi1 in preadipocytes blocks the induction of PPAR?2 and suppresses adipocyte differentiation. Evi1 binds with C/EBP? to regulatory sites in the Ppar? locus at early stages of adipocyte differentiation, coincident with the induction of Ppar?2 expression. These results indicate that Evi1 is a key regulator of adipogenic competency.

Ishibashi, Jeff; Firtina, Zeynep; Rajakumari, Sona; Wood, Kathleen H.; Conroe, Heather M.; Steger, David J.

2012-01-01

181

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

182

Mapping the Stratigraphy of Booming Sand Dunes  

NASA Astrophysics Data System (ADS)

Booming dunes emit a loud rumbling sound after a man-made or natural sand avalanche is generated on the slip face of a large desert dune. The sound consist of one dominant frequency (70 - 105 Hz) with several higher harmonics. A recent publication (Vriend et al., 2007) presented a model of an internal, natural waveguide that propagates the booming emission, amplifies the sound, and sets the booming frequency. The mapping of the subsurface layering, which is necessary for the existence of a waveguide, prompted additional work on the dune structure and stratigraphy. The current work highlights geophysical measurements at Eureka Dunes in Death Valley National Park, CA and Dumont Dunes in the Mojave Desert, CA. Seismic refraction studies indicate strong layering with large velocity jumps across the interfaces. Ground Penetrating Radar (GPR) profiles, at frequencies of 100 MHz and 200 MHz, map out the stratigraphic structure of the dunes. Variations in the near surface layering are able to predict the seasonal variability in booming frequency both quantitatively and qualitatively. The Kirchhoff migrated GPR profiles are superimposed on the local topography obtained with a laser rangefinder. The complex dune structure is resolved to a depth of over 30 meters for the 100 MHz antenna. The GPR profiles of the longitudinal Eureka dune display complex internal structures from old dune crests. Both slopes have slip faces at 30 degrees with parallel layering (< 2m) at the near surface. At the transverse Dumont dune the GPR profile exhibits strong parallel layering on the booming leeward slipface only. The shallower windward face features a remarkable tilted repetitive layering that cuts through the surface. At Dumont Dunes the layering on the leeward face explains the change in booming frequency between 70 - 95 Hertz in the period 2005 - 2008. The tilted layering structure of the shallow windward face prevents the formation of a waveguide and is never able to sustain the booming sound. The Dumont dune progresses slowly, estimated at ~ 1 m/year from correlating satellite images, by forming new slip faces on the leeward face over time. Large precipitation events may cause a new layer to form. Sand sampling provides a quantitative measure on the chemical composition and water content of the layering.

Vriend, N. M.; Hunt, M. L.; Clayton, R. W.

2008-12-01

183

Ball-cratering abrasion tests of high-Cr white cast irons  

Microsoft Academic Search

The application of a ball-cratering method to test three-body abrasive wear of bulk materials in the presence of large abrasive particles has been investigated. Three high-Cr white cast irons (WCIs) with different material properties were used as wear samples. Abrasive slurries contained two types of abrasive particles, silica sand and crushed quartz. Silica sand and crushed quartz particles have similar

G. B. Stachowiak; G. W. Stachowiak; O. Celliers

2005-01-01

184

Gasification of oil sand coke: Review  

Microsoft Academic Search

The production of synthetic crude from the tar sands in Western Canada has been steadily increasing. Most of the delayed coke produced by Suncor is combusted on site, whereas all fluid coke produced by Syncrude is stockpiled. The database on the chemical and physical properties of the oil sand coke, including the composition and fusion properties of the mineral matter,

Edward Furimsky

1998-01-01

185

Hydrodynamic analysis of feeding in sand dollars  

Microsoft Academic Search

Subtidal sand dollars, Dendraster excentricus, assume an inclined posture under conditions of moderate water flow (10 cm s-1 to 2 m s-1). In this posture, when the test is in the usual position parallel to the water flow, the test acts as a lifting body. Analysis of the hydrodynamic characteristics of the sand dollar test was accomplished by slender body

Patricia L. O'Neill

1978-01-01

186

Systems for producing bitumen from tar sands  

Microsoft Academic Search

A system for producing bitumen from unconsolidated tar sands in an open well includes a screen positioned in the well large enough to pass a majority of the formation sand and small enough to retain a gravel packing material, a pair of high pressure fluid lateral nozzles fracturably fastened in the bottom of the screen, a wash pipe extending down

Payton

1978-01-01

187

Introduction to Exploring Sand and Water  

ERIC Educational Resources Information Center

|What happens when children pour water through a funnel? They begin to understand science and math concepts such as flow, force, gravity, and volume. What happens when children mold sand to create a tunnel? They develop skills in areas such as problem solving and predicting. They also gain knowledge about absorption and the properties of sand and…

Early Childhood Today, 2006

2006-01-01

188

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

189

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

190

New production techniques for Alberta oil sands  

Microsoft Academic Search

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

M. A. CARRIGY

1986-01-01

191

New Production Techniques for Alberta Oil Sands  

Microsoft Academic Search

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

Maurice A. Carrigy

1986-01-01

192

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

193

Sand dams: Africa's answer to climate change?  

Microsoft Academic Search

In semi-arid regions of Africa, sand dam technology can make a significant contribution to mitigating the impacts of climate change by providing a low-cost solution to the problem of water conservation. Despite clear benefits, sand dams are used relatively little as they are very labour intensive, meaning a lack of effective community engagement can endanger project implementation and sustainability. Excellent

Simon Maddrell; Sophie Bown

194

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

195

Horizontal oil shale and tar sands retort  

Microsoft Academic Search

A horizontal retorting apparatus and method are disclosed designed to pyrolyze tar sands and oil shale, which are often found together in naturally occurring deposits. The retort is based on a horizontal retorting tube defining a horizontal retort zone having an upstream and a downstream end. Inlet means are provided for introducing the combined tar sands and oil shale into

Thomas

1982-01-01

196

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...

197

Sand reinforced with shredded waste tires  

SciTech Connect

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

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

1996-09-01

198

Estimating Sand–Shale Formation Pore Pressure  

Microsoft Academic Search

This article presents a comprehensive evaluation method of estimating sand–shale formation pore pressure by using sonic velocity and other logging data. The method takes the influence of porosity, density, shale content, effective stress, and some other physical properties of sand–shale formation on sonic velocity into account. The influence and related logging data are combined to estimate the effective stress, and

F. Honghai; Y. Zhi; J. Rongyi

2011-01-01

199

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

200

Earth-like sand fluxes on Mars  

NASA Astrophysics Data System (ADS)

Strong and sustained winds on Mars have been considered rare, on the basis of surface meteorology measurements and global circulation models, raising the question of whether the abundant dunes and evidence for wind erosion seen on the planet are a current process. Recent studies showed sand activity, but could not determine whether entire dunes were moving--implying large sand fluxes--or whether more localized and surficial changes had occurred. Here we present measurements of the migration rate of sand ripples and dune lee fronts at the Nili Patera dune field. We show that the dunes are near steady state, with their entire volumes composed of mobile sand. The dunes have unexpectedly high sand fluxes, similar, for example, to those in Victoria Valley, Antarctica, implying that rates of landscape modification on Mars and Earth are similar.

Bridges, N. T.; Ayoub, F.; Avouac, J.-P.; Leprince, S.; Lucas, A.; Mattson, S.

2012-05-01

201

Earth-like sand fluxes on Mars.  

PubMed

Strong and sustained winds on Mars have been considered rare, on the basis of surface meteorology measurements and global circulation models, raising the question of whether the abundant dunes and evidence for wind erosion seen on the planet are a current process. Recent studies showed sand activity, but could not determine whether entire dunes were moving--implying large sand fluxes--or whether more localized and surficial changes had occurred. Here we present measurements of the migration rate of sand ripples and dune lee fronts at the Nili Patera dune field. We show that the dunes are near steady state, with their entire volumes composed of mobile sand. The dunes have unexpectedly high sand fluxes, similar, for example, to those in Victoria Valley, Antarctica, implying that rates of landscape modification on Mars and Earth are similar. PMID:22596156

Bridges, N T; Ayoub, F; Avouac, J-P; Leprince, S; Lucas, A; Mattson, S

2012-05-09

202

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

203

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

204

Coating of silica sand with aluminosilicate clay.  

PubMed

The objective of this work was to coat aluminosilicate clays on an inert silica support, and to characterize the properties and stability of the clay-silica coating. Two polymers, polyacrylamide (PAM) and polyvinyl alcohol (PVA), were used to bind kaolinite, illite, and smectite onto silica grains. The clay-polymer composites were studied by X-ray diffraction, FTIR, and electrophoretic mobility. Clay coatings on silica grains were characterized by mass coverage, scanning electron microscopy, specific surface area, and pH stability. Silica sand was successfully coated with clays by using the two polymers, but with PVA, the clay coating had a greater mass coverage and was more stable against pH variations. Less polymer was needed for the clay coating using PVA as compared to using PAM. Clay-polymer complexes and pure clay minerals had similar cation exchange capacities and electrophoretic mobilities, indicating that overall surface charge of the clays was little affected by the polymers. Some decrease in hydrophilicity was observed for illite and smectite when clays where coated with the polymers. The methodology reported here allows the generation of a clay-based porous matrix, with hydraulic properties that can be varied by adjusting the grain size of the inert silica support. PMID:16085082

Jerez, Jorge; Flury, Markus; Shang, Jianying; Deng, Youjun

2005-08-08

205

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

206

BMM SHAKEOUT AND VIBRATING CONVEYOR TRANSPORT SAND AND CASTINGS TO ...  

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

BMM SHAKEOUT AND VIBRATING CONVEYOR TRANSPORT SAND AND CASTINGS TO SEPARATIONS SCREENS. - Southern Ductile Casting Company, Shaking, Degating & Sand Systems, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

207

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

208

Desiccation, cryopreservation and water relations parameters of white spruce (Picea glauca) and interior spruce (Picea glauca x engelmannii complex) somatic embryos.  

PubMed

Effects of drying and cryopreservation on survival of spruce (Picea glauca (Moench) Voss and Picea glauca x engelmannii complex) somatic embryos (SEs) were investigated with the aim of developing simple and robust protocols for embryo storage. Somatic embryos dried over salt solutions of known water potential (Psi) survived removal of virtually all free water, to a relative water content (RWC) of approximately 0.13, a value similar to that for spruce zygotic embryos from dry seed. Desiccated SEs also survived subsequent freezing in liquid nitrogen, without the addition of cryoprotectant or pre-culture steps. Highest survival (> 80%) after freezing in liquid nitrogen was in embryos pre-dried to Psi of -15 to -20 MPa, which yielded RWC close to predicted bound (apoplastic) water values. Low (< 35%) or no survival after freezing was observed in embryos pretreated at higher Psi (above -5 MPa) or at very low Psi (-540 MPa, using silica gel), respectively. PMID:11731340

Percy, R E; Livingston, N J; Moran, J A; Von Aderkas, P

2001-12-01

209

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

210

Influence of sand grain diameter and wind velocity on lift-off velocities of sand particles.  

PubMed

In this paper, the velocities of sand particles near the sand bed in the saltation cloud were measured in a wind tunnel through an improved experimental scheme of the Particle Image Velocimetry (PIV) system. The influences of the diameter of sand particles in the saltation cloud and wind velocity on the probability distribution function (PDF) of lift-off velocities of sand particles were investigated. Results demonstrate that for the sand particles saltating above the sand bed with the mean grain diameter (d m = 0.3 mm), smaller and larger ones have the same velocity distribution, and wind velocity has no obvious influence on the distribution shape of the lift-off velocities, i.e., the PDFs of the horizontal and vertical lift-off velocities both follow a lognormal distribution, but the diameter of sand particles in the saltation cloud and wind velocity have an influence on the parameters of the PDF of horizontal and vertical lift-off velocities. Eventually, we present formulas to describe the PDF of lift-off velocities of sand particles with regard to the influence of wind velocity and the diameter of sand particles in the saltation cloud above the sand bed with d m = 0.3 mm. PMID:23695368

Bo, Tian-Li; Zheng, Xiao-Jing; Duan, Shao-Zhen; Liang, Yi-Rui

2013-05-24

211

Horizontal oil shale and tar sands retort  

SciTech Connect

A horizontal retorting apparatus and method are disclosed designed to pyrolyze tar sands and oil shale, which are often found together in naturally occurring deposits. The retort is based on a horizontal retorting tube defining a horizontal retort zone having an upstream and a downstream end. Inlet means are provided for introducing the combined tar sands and oil shale into the upstream end of the retort. A screw conveyor horizontally conveys tar sands and oil shale from the upstream end of the retort zone to the downstream end of the retort zone while simultaneously mixing the tar sands and oil shale to insure full release of product gases. A firebox defining a heating zone surrounds the horizontal retort is provided for heating the tar sands and oil shale to pyrolysis temperatures. Spent shale and tar sands residue are passed horizontally beneath the retort tube with any carbonaceous residue thereon being combusted to provide a portion of the heat necessary for pyrolysis. Hot waste solids resulting from combustion of spent shale and tar sands residue are also passed horizontally beneath the retort tube whereby residual heat is radiated upward to provide a portion of the pyrolysis heat. Hot gas inlet holes are provided in the retort tube so that a portion of the hot gases produced in the heating zone are passed into the retort zone for contacting and directly heating the tar sands and oil shale. Auxiliary heating means are provided to supplement the heat generated from spent shale and tar sands residue combustion in order to insure adequate pyrolysis of the raw materials with varying residual carbonaceous material.

Thomas, D.D.

1982-08-31

212

8? x 10? black and white photographic print made from ...  

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

8? x 10? black and white photographic print made from original 1933, 8? x 10? black and white photographic negative. New 4? x 5? archival negative made from print. Original photographer unknown. Original 8? x 10? negative located in the files of the New Orleans Public Belt Railroad administrative offices at 5100 Jefferson Highway, Jefferson, LA 70123. SEPTEMBER 25, 1933 PHOTOGRAPH NO. 41 OF CONTRACT NO. 3 SHOWING MAIN BRIDGE PLACING SAND ISLAND FILL AT PIER NO. III. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

213

8? x 10? black and white photographic print made from ...  

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

8? x 10? black and white photographic print made from original 1933, 8? x 10? black and white photographic negative. New 4? x 5? archival negative made from print. Original photographer unknown. Original 8? x 10? negative located in the files of the New Orleans Public Belt Railroad administrative offices at 5100 Jefferson Highway, Jefferson, LA 70123. DECEMBER 18, 1933 PHOTOGRAPH NO. 87 OF CONTRACT NO. 3 SHOWING MAIN BRIDGE SAND ISLAND FILL PIER I. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

214

Polishing acrylic lens materials after sand impact  

NASA Astrophysics Data System (ADS)

Commercial grade PMMA samples designed for CPV primary lens applications were subjected to sand impact in a wind tunnel. Defects caused by the impinging sand particles led to a decrease of direct transmittance and increase of haze. The observed changes increased with increasing mass and velocity of the sand deposited. Using a cotton buffing wheel it was possible to restore the PMMA surface almost back to its initial state and direct transmittance and haze back to their original values. Structural data from surface roughness measurements and SEM micrographs correlated well with the optical quantities.

Arndt, Thomas; Battenhausen, Peter; Kilian, Philipp; Sättler, Roland

2013-09-01

215

Optimizing fracture toughness and abrasion resistance in white cast irons  

Microsoft Academic Search

A series of twelve Cr-Mo white irons varying in carbide volume from 7 to 45 pct were tested for dynamic fracture toughness\\u000a and wet sand abrasion resistance. Carbon content was varied from 1.4 to 3.9 pct. Two matrix microstructures were employed,\\u000a and the compositions (copper and chromium content) were varied to assure constant matrix compositions. Chromium was varied\\u000a from 11.6

Karl-Heinz Zum Gahr; Douglas V. Doane

1980-01-01

216

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

217

Confronting White Privilege  

ERIC Educational Resources Information Center

Even as the United States becomes more diverse, a new era of "white flight" is unfolding. Whether they live in urban, suburban or rural communities, white students are likely to attend schools that reinforce their perceptions of cultural dominance. The average white student attends a school where 77 percent of the student body is of their race.…

Swalwell, Katy

2012-01-01

218

Confronting White Privilege  

ERIC Educational Resources Information Center

|Even as the United States becomes more diverse, a new era of "white flight" is unfolding. Whether they live in urban, suburban or rural communities, white students are likely to attend schools that reinforce their perceptions of cultural dominance. The average white student attends a school where 77 percent of the student body is of their race.…

Swalwell, Katy

2012-01-01

219

Organoleptically enhanced white chocolate  

US Patent & Trademark Office Database

This invention is directed to an enhanced white chocolate to which has been added isovaleric acid in an amount effective to provide enhanced organoleptic attributes compared to a conventional white chocolate. The invention is also directed to the preparation of the enhanced white chocolate.

2012-03-20

220

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

221

Measuring White Specks in Dyed Cotton Fabrics Using the Optimas Imaging System  

Technology Transfer Automated Retrieval System (TEKTRAN)

White specks are fiber clusters that appear as small white flecks on dyed fabrics. Their minute size and depth of shade, increases the subjectivity and complexity. No standard methods exist to quantify the level of white specks. Image analysis was evaluated as a means to measure white specks in or...

222

The kinetics of the pyrolysis of tar sands and of the combustion of coked sands  

Microsoft Academic Search

The kinetic parameters for the pyrolysis of bitumen-impregnated sandstone (tar sand) particles have been determined by thermogravimetric analysis (TGA). The tar sand deposits investigated in this study, all of which are oil-wet sands from the Uinta Basin the State of Utah, included PR Spring Rainbow I, Whiterocks, and Sunnyside. The isothermal experiments indicated that first-order kinetics fit most of the

Lin

1988-01-01

223

Testing of TMR Sand Mantis Final Report.  

National Technical Information Service (NTIS)

Screening tests of Sand Mantis candidate materials selected for erosion resistance have been completed. The results of this testing identified that over a relatively short period of operation (<1 hour), measurable erosion will occur in each of the candida...

D. Krementz W. L. Daughtery

2007-01-01

224

Fate of Petroleum Hydrocarbons in Beach Sand.  

National Technical Information Service (NTIS)

The fate of the petroleum hydrocarbons from Chevron bunker fuel has been studied in natural beaches, sand-containing lysimeters, and laboratory experiments. The importance of various physical, chemical and biological processes for the dispersal and degrad...

1972-01-01

225

Fate of Petroleum Hydrocarbons in Bleach Sand.  

National Technical Information Service (NTIS)

The fate of the petroleum hydrocarbons from Chevron bunker fuel has been studied in natural beaches, sand-containing lysimeters, and laboratory experiments. The importance of various physical, chemical and biological processes for the dispersal and degrad...

H. E. Guard A. Cobet

1972-01-01

226

Comparison of SAND-II and FERRET.  

National Technical Information Service (NTIS)

A comparison was made of the advantages and disadvantages of two codes, SAND-II and FERRET, for determining the neutron flux spectrum and uncertainty from experimental dosimeter measurements as anticipated in the FFTF Reactor Characterization Program. Thi...

D. W. Wootan F. Schmittroth

1981-01-01

227

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

228

Foundation Precompression with Vertical Sand Drains.  

National Technical Information Service (NTIS)

The precompression technique combined with vertical sand drains is often applicable where structure loads are reasonably uniform and do not include heavy concentrated loadings and where earth fills for highways do not exceed 40 to 50 ft, although this lim...

S. J. Johnson

1969-01-01

229

White Students Reflecting on Whiteness: Understanding Emotional Responses  

Microsoft Academic Search

In the present investigation, we explored potential predictors of White students' general emotional responses after they reflected on their Whiteness in a semistructured interview (n = 88) or written reflection (n = 187). Specifically, we examined how color-blindness (i.e., awareness of White privilege) and racial affect (i.e., White empathy, White guilt, and White fear), assessed before the interview or written

Nathan R. Todd; Lisa B. Spanierman; Mark S. Aber

2010-01-01

230

Advanced inline measurement and control tools for sand filling and compaction in lost foam casting  

NASA Astrophysics Data System (ADS)

Lost Foam Casting (LFC) enables metal casters to produce complex parts by making foam patterns having the same geometry as the desired finished parts. Among the greatest strengths of LFC process is that it allows designers to consolidate parts, reduce machining and minimize assembly operations. One of the key steps in the LFC process takes place in the compaction box, where the foam pattern is suspended in a steel container that is vibrated while sand is added to surround the pattern. The sand provides the mechanical support to the pattern as molten metal is poured into the mold. Discussed in this paper will be the development of an advanced sensor array for the measurement and control of the sand compaction stage. Compaction of the sand is key in controlling casting distortion and is instrumental in the efficiency rating of the LFC process. Too much compaction can cause the foam part to distort or even get crushed. Too little compaction can lead to a defective final product due to inadequate support of the foam part or lack of sand flow into small cavities in the foam part. To understand and control the behavior of the sand compaction stage, the key parameters that must first be measured are: (1) Energy imparted on the compaction box, sand and foam part, (2) compaction of the sand in the casting box, and (3) distortion of the foam part. The sensor array is to be placed inline in order to give direct feedback that can then be used in both passive and active process control.

Whelan, Matthew J.; Janoyan, Kerop D.

2004-07-01

231

Dimensionless and unbiased CPT interpretation in sand  

NASA Astrophysics Data System (ADS)

The cone penetration test (CPT) is widely used, and although initially developed as a stratigraphic logging tool its excellent repeatability and accuracy offers a benchmark quantitative test for sand in particular. A continuing difficulty, however, is that the CPT does not measure any soil property directly, so that parameters of interest must be recovered from solution of an inverse boundary value problem, which is difficult. To date most CPT interpretations in sand have been based on very limited calibration testing carried out in large chambers on a few sands from which mappings are developed. But there are differences in the CPT response from one sand to another leaving the interpretation imprecise (and arguably even speculative) because these differences remain poorly understood. In this paper we use the familiar spherical cavity expansion analogy to the CPT including large strains and a good, critical-state-based, soil model to develop a pattern of behaviour which we then compare to some of the reference chamber test data. We find that one of the issues of dispute in the empirical interpretation methods, the so-called stress-level effect, is caused by neglect of elasticity and that there are several additional parameters of first-order significance to cavity expansion in sands. More generally, we show that the difference in CPT response between various chamber sands in predicted. Our results are cast in dimensionless form and the inversion illustrates that extreme care is required in interpreting CPT data if the in situ sand state is to be determined with precision approaching that suggested as achievable by the repeatability of the CPT data itself. Aspects requiring particular care in interpreting CPT data in sand are discussed.

Shuttle, Dawn; Jefferies, Michael

1998-05-01

232

Cyclic undrained behavior of silty sand  

Microsoft Academic Search

Laboratory cyclic triaxial tests were performed to investigate the effect of fine content on the pore pressure generation in sand. Strain-controlled, consolidated undrained tests have been performed with a cyclic shear strain range of 0·015-1·5%. These tests were carried to 1000 cycles or to initial liquefaction, which ever occurred first. Triaxial tests were performed on pure sand silt specimens and

D. Erten; M. H. Maher

1995-01-01

233

Developing Alberta's oil sands, 1920--2002  

NASA Astrophysics Data System (ADS)

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

Chastko, Paul Anthony

234

White phosphorus activation at a metal-phosphorus triple bond: a new route to cyclo-triphosphorus or cyclo-pentaphosphorus complexes of niobium.  

PubMed

The Nb-P triple bond in [P?Nb(N[Np]Ar)(3)](-) (Np = CH(2)(t)Bu; Ar = 3,5-Me(2)C(6)H(3)) has produced the first case of P(4) activation by a metal-ligand multiple bond. Treatment of P(4) with the sodium salt of the niobium phosphide complex in weakly coordinating solvents led to formation of the cyclo-P(3) anion [(P(3))Nb(N[Np]Ar)(3)](-). Treatment in tetrahydrofuran (THF) led to the formation of a cyclo-P(5) anion [(Ar[Np]N)(?(4)-P(5))Nb(N[Np]Ar)(2)](-), which represents a rare example of a substituted pentaphosphacyclopentadienyl ligand. The P(4) activation pathway was shown to depend on the dimer-monomer equilibrium of the niobium phosphide reagent, which, in turn, depends on the solvent used for the reaction. The pathway leading to the cyclo-P(3) product was shown to require a 2:1 ratio of the phosphide anion to P(4), while the cyclo-P(5) formation requires a 1:1 ratio. The cyclo-P(3) salt has been isolated in 56% yield as orange crystals of the [Na(THF)](2)[(P(3))Nb(N[Np]Ar)(3)](2) dimer or in 83% yield as an orange powder of [Na(12-crown-4)(2)][(P(3))Nb(N[Np]Ar)(3)]. A solid-state X-ray diffraction experiment on the former salt revealed that each Nb-P(3) unit exhibits pseudo-C(3) symmetry, while (31)P NMR spectroscopy showed a sharp signal at -223 ppm that splits into a doublet-triplet pair below -50 °C. It was demonstrated that this salt can serve as a P(3)(3-) source upon treatment with AsCl(3), albeit with modest yield of AsP(3). The cyclo-P(5) salt was isolated in 71% yield and structurally characterized from red crystals of [Na(THF)(6)][(Ar[Np]N)(?(4)-P(5))Nb(N[Np]Ar)(2)]. The anion in this salt can be interpreted as the product of trapping of an intermediate pentaphosphacycplopentadienyl structure through migration of one anilide ligand onto the P(5) ring. The W(CO)(5)-capped cyclo-P(3) salt was also isolated in 60% yield as [Na(THF)][(OC)(5)W(P(3))Nb(N[Np]Ar)(3)] from the activation of 0.5 equiv of P(4) with the sodium salt of the tungsten pentacarbonyl adduct of the niobium phosphide anion. PMID:21894967

Tofan, Daniel; Cossairt, Brandi M; Cummins, Christopher C

2011-09-06

235

Phenolic removal processes in biological sand filters, sand columns and microcosms.  

PubMed

This study evaluated the removal processes involved in the removal of the phenolic component of winery wastewater in biological sand filters, sand columns and sand microcosms. It was found that at low influent phenolic concentrations, complete organic removal was accomplished, but at high concentrations, there was incomplete substrate removal and an accumulation of potentially toxic metabolites, including catechol. The sand provided a suitable substrate for the treatment of phenolic-laden waste, and both biotic (48%) and abiotic (52%) removal mechanisms effected the removal of model phenolics. Prior acclimation of microbial communities increased the biodegradation rate of phenolic acids significantly. PMID:22728790

Welz, P J; Ramond, J-B; Cowan, D A; Burton, S G

2012-05-18

236

Analysis of sand particles' lift-off and incident velocities in wind-blown sand flux  

NASA Astrophysics Data System (ADS)

In the research of windblown sand movement, the lift-off and incident velocities of saltating sand particles play a significant role in bridging the spatial and temporal scales from single sand particle's motion to windblown sand flux. In this paper, we achieved wind tunnel measurements of the movement of sand particles near sand bed through improving the wind tunnel experimental scheme of particle image velocimetry (PIV) and data processing method. And then the influence of observation height on the probability distributions of lift-off and incident velocities of sand particles was analyzed. The results demonstrate that the observation height has no obvious influence on the distribution pattern of the lift-off and incident velocities of sand particles, i.e., the probability distribution of horizontal and vertical velocities of lift-off and incident sand particles follow a Gaussian distribution and a negative exponential distribution, respectively. However, it influences the center of the Gaussian distribution, the decay constant and the amplitude of the negative exponential distribution.

Bo, Tian-Li; Zheng, Xiao-Jing; Duan, Shao-Zhen; Liang, Yi-Rui

2013-04-01

237

Electric field in windblown sand flux with thermal diffusion  

Microsoft Academic Search

A theoretical model considering thermal diffusion (TD) from a sand bed is suggested in this paper to account for the effect of both TD and the electric field produced by charged sand grains during the evolution of windblown sand flux, where the coupled interaction among wind speeds in the vertical and the horizontal directions, sand movement (saltation, suspension, and creep),

Gaowei Yue; Xiaojing Zheng

2006-01-01

238

The saltations of different sized particles in aeolian sand transport  

Microsoft Academic Search

Wind tunnel experiments were performed in order to investigate the effect of mixing on the aeolian transport of sands with different grain sizes. Two types of sand with different grain size distributions and an equal-mass binary mixture of these sands were used. Comparing the gradients of their measured mass flux profiles and some published profiles for mixed sand transport with

Mao Xing; Chuanyu Wu; Michael J. Adams

2011-01-01

239

Deposition of carbonate mud beds within high-energy subtidal sand Dunes, Bahamas  

SciTech Connect

Laminated, carbonate mud beds are being deposited in the interisland channels of the Exuma Cays in the Bahamas. They are associated with stromatolites and interbedded with ooid sands that form large migrating subtidal dunes on flood tidal deltas and bars. Currents up to 3 knots sweep in and out of the 4-8 m deep channels 3 hours out of every 6 hours, creating a high-energy bank margin environment not usually considered to be the site of mud-sized particle deposition. Mud deposits reach thicknesses of 1 m and have individual beds 2-5 cm thick. When exposed to flowing seawater, bed surfaces become encrusted with carbonate cement and algal mats. The white interior of mud beds between the crusts appears homogeneous, is soft, and has the consistency of ''tooth paste.'' Loose uncemented ooid sand is found above and below the mud beds, showing that both are occupying the same depositional environment. Rip-up clasts of the crusted mud beds, formed by scour of underlying sands, are carried throughout the channels and accumulate as a lag deposit within the troughs of migrating dunes. Some clasts are colonized by algal mats that trap ooid and skeletal sands forming stromatolite structures that can grow up to 2 m high.

Dill, R.F.; Steinen, R.P.

1988-01-01

240

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

241

Petrogenesis and tectonic setting of Cadomian felsic igneous rocks, Sand?kl? area of the western Taurides, Turkey  

Microsoft Academic Search

In the Sand?kl? (Afyon) region, western Taurides, the Late Proterozoic rocks of the Sand?kl? basement complex are composed of low-grade meta-sedimentary rocks (Güvercinoluk Formation) intruded by felsic rocks (Kestel Cay? Porphyroid Suite, KCPS). The KCPS is a deformed and highly sheared, dome-shaped rhyolitic body with a granitic core. Quartz porphyry dikes intrude both the slightly metamorphic igneous and the sedimentary

Semih Gürsu; M. Cemal Göncüoglu

2006-01-01

242

Phylogeography of the neotropical sand fly Lutzomyia longipalpis inferred from mitochondrial DNA sequences  

Microsoft Academic Search

Sand flies in the Lutzomyia longipalpis species complex include the primary vector of Leishmania chagasi, the etiologic agent of visceral leishmaniasis in the Neotropics. Twelve L. longipalpis populations from South and Central America were compared using the cytochrome c oxidase I (COI) gene from the mitochondrial genome. The haplotype profiles for each population revealed that the majority of sequence variation

J. C. Arrivillaga; D. E. Norris; M. D. Feliciangeli; G. C. Lanzaro

2002-01-01

243

Influence of capillarity on a simple harmonic oscillating water table: Sand column experiments and modeling  

Microsoft Academic Search

Comprehensive measurements of the water table response to simple harmonic forcing at the base of a sand column are presented and discussed. In similar experiments, Nielsen and Perrochet (2000) observed that fluctuations in the total moisture were both damped and lagged relative to the water table fluctuations. As a result, the concept of a complex effective porosity was proposed as

Nick Cartwright; Peter Nielsen; Pierre Perrochet

2005-01-01

244

Numerical modeling of stress–strain behavior of sand under cyclic loading  

Microsoft Academic Search

Analysis of soil response to cyclic loading is a complex problem due to the participation of a large number of loading conditions and physical properties. In this study, a promising variant of genetic programming (GP), namely multi expression programming (MEP) is utilized to model stress–strain behavior of sands subjected to large amplitude regular cyclic loading. Generalized MEP-based formulations are derived

Habib Shahnazari; Yasser Dehnavi; Amir Hossein Alavi

2010-01-01

245

Assessing White-tailed Deer Abundance in the Town of Barnstable, Cape Cod, Massachusetts  

Microsoft Academic Search

White-tailed deer (Odocoileus virginianus) are abundant throughout most of the eastern United States. However, in and around the town of Barnstable on Cape Cod, Massachusetts, there is a notable relative paucity of the species. I sought to seek rough population numbers\\/trends of deer through direct sightings and tracking (on sand, dirt, and snow) over the past 16 years (1993 -

246

A wind tunnel study of aeolian sand transport on a wetted sand surface using sands from tropical humid coastal southern China  

Microsoft Academic Search

This article reported a wind tunnel test of sediment transport related to surface moisture content and wind velocity using\\u000a sands from tropical humid coastal area. A 1 mm-thick portion of surface sand was scraped using a self-made sediment sampler,\\u000a and the gravimetric moisture content was determined. Sand transport was measured via a standard vertical sand trap with a\\u000a 60 cm height. The

Qingjie Han; Jianjun Qu; Kongtai Liao; Shujuan Zhu; Kecun Zhang; Ruiping Zu; Qinghe Niu

247

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

248

Meso-scale cooling effects of high albedo surfaces: Analysis of meteorological data from White Sands National Monument and White Sands Missile Range  

Microsoft Academic Search

Urban summer daytime temperatures often exceed those of the surrounding rural areas. Summer ``urban heat islands`` are caused by dark roofs and paved surfaces as well as the lack of vegetation. Researchers at Lawrence Berkeley Laboratory are interested in studying the effects of increasing the albedo of roof tops and paved surfaces in order to reduce the impacts of summer

B. Fishman; H. Taha; H. Akbari

1994-01-01

249

Recycling of iron foundry sand and glass waste as raw material for production of whiteware.  

PubMed

The purpose of this study was to evaluate the production feasibility of triaxial whiteware using sand from cast iron moulds as a raw material instead of silica, and recycled glass in place of feldspar. Formulations were prepared using sand, glass waste, and white-firing clay such that only 50% of the composition was virgin material (clay). The ceramic bodies were formed by pressing and fired at different temperatures (between 1100 and 1300 degrees C). Specimens were characterized in terms of green density prior to firing; and their flexural strength, linear shrinkage, and water absorption were measured after firing. The microstructure was determined by scanning electron microscopy. Possible environmental impacts of this recycling process were also evaluated, through solubility and leaching tests, according to Brazilian standards. Gaseous emissions during the firing process were also analysed. The results showed that it is possible to produce triaxial ceramics by using such alternative raw materials. PMID:16496871

Bragança, Saulo R; Vicenzi, Juliane; Guerino, Kareline; Bergmann, Carlos P

2006-02-01

250

The fracture characteristics of crushed limestone sand concrete  

SciTech Connect

The use of crushed sand as a fine aggregate has rapidly increased due to a shortage of river sand. Accordingly, research on crushed sand concrete is required. In this research, the fracture characteristics of crushed limestone sand concrete were experimentally investigated through a wedge splitting test, and the results were compared with those of crushed granite sand concrete and river sand concrete. The strength of crushed limestone sand concrete was also investigated. It was shown that the fracture energy of concrete was little influenced by the type of fine aggregate. In addition, the fracture energy of crushed sand concrete was slightly higher than that of river sand concrete. This seems to be due to very fine sand (VFS) included in crushed sand, which tends to improve the cohesion between cement paste and aggregate. Also, the fracture energy was not proportionally increased with an increase of concrete strength. The characteristic length of crushed limestone sand concrete was almost the same as that of river sand concrete or crushed granite sand concrete. The characteristic length greatly decreased as the strength of concrete increased.

Kim, J.K.; Lee, C.S.; Park, C.K. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Civil Engineering; Eo, S.H. [Changwon National Univ. (Korea, Republic of). Dept. of Civil Engineering

1997-11-01

251

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 ...

252

Influence of cementation on liquefaction of sands  

SciTech Connect

Cementation can exist in a sand naturally or it can be added artificially. In either case, it is known to increase the resistance of a sand to liquefication, and can be a critical factor in engineering decisions about site response. This investigation involves testing of weakly cemented sands which have a range of cementation levels and unit weights. Both triaxial and cubical cyclic shear devices are used in the testing. The cubical shear apparatus is used to allow assessment of possible stress concentration effects in the triaxial device, and to investigate loading under multiaxial stress conditions. The experimental results are used to separate the effects of unit weight and cementation, and to define the conditions where cementation begins to override the influence of unit weight.

Clough, G.W.; Kuppusamy, T. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA). Dept. of Civil Engineering); Iwabuchi, J. (Central Res. Inst. for Constr. Tech., Tokyo (JP)); Rad, N.S. (Norwegian Geotech. Inst., Oslo (NO))

1989-08-01

253

Planet-wide sand motion on mars  

USGS Publications Warehouse

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

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

2012-01-01

254

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

255

High temperature stable sand control method  

SciTech Connect

This invention relates to a method for treating wells completed in subterranean formations to form a mechanically stable, permeable mass which permits flow of fluids therethrough into or from the well, while restricting the movement of unconsolidated earth formation particles such as sand into the well. This method is especially suitable for treating producing wells in a subterranean formation being subjected to thermal oil recovery stimulation of viscous oil production such as by steam flooding, which causes rapid deterioration of consolidated sand or gravel masses formed with plastic resins. The method comprises contacting sand with an aqueous solution of calcium hydroxide, plus an effective amount of calcium salt having solubility greater than calcium hydroxide, such as calcium chloride, plus an alkalinity agent such as sodium hydroxide.

Park, J.H.

1980-11-11

256

Grain segregation mechanism in aeolian sand ripples  

NASA Astrophysics Data System (ADS)

Many sedimentary rocks are formed by migration of sand ripples. Thin layers of coarse and fine sand are present in these rocks, and understanding how layers in sandstone are created has been a longstanding question. Here, we propose a mechanism for the origin of the most common layered sedimentary structures such as inverse graded climbing ripple lamination and cross-stratification patterns. The mechanism involves a competition between three segregation processes: (i) size-segregation and (ii) shape-segregation during transport and rolling, and (iii) size segregation due to different hopping lengths of the small and large grains. We develop a discrete model of grain dynamics which incorporates the coupling between moving grains and the static sand surface, as well as the different properties of grains, such as size and roughness, in order to test the plausibility of this physical mechanism.

Makse, H. A.

2000-02-01

257

Preliminary evaluation of chemical indicators for the analysis of production losses from tar sand recovery  

SciTech Connect

This report presents the results of a preliminary investigation to evaluate changes in the chemical composition of thermally altered tar sand bitumen. The objective of the study was to determine if changes in the chemical composition of the tar sand bitumen can be correlated to chemically related production losses or thermal history of the bitumen. Tar sand samples from the Tar Sand Triangle deposit in southeastern Utah were thermally altered under autogenous conditions at temperatures of 380/sup 0/C, 400/sup 0/C, and 420/sup 0/C for time periods ranging from 1 to 24 hours. The thermally altered tar sands was serially extracted with normal heptane, toluene, and pyridine. The normal heptane extracts from each thermal alteration experiment were analyzed by combined gas chromatography/mass spectrometery (GC/MS) to determine the presence of several classes of compounds. The heptane fractions from the thermally altered tar sand represent a complex mixture that can not be evaluated using conventional combined GC/MS techniques. For this reason, the presence of the different classes of compounds was determined by profiling ions selected to represent each class of targeted compounds. The classes of compounds targeted for this analysis included normal alkanes, tricyclic diterpanes, pantacyclic triterpanes, and aromatic species having general empirical formulas ranging from C/sub n/H/sub 2n-6/ through C/sub n/H/sub 2n-40/. The results of this investigation indicate that the pentacyclic triterpanes are the only class of compounds that follow a trend with the thermal alteration conditions. The relative intensity of the pentacyclic triterpanes decreases with increasing exposure time for each temperature investigated. This class of compounds may be useful for tracing the thermal history of tar sand bitumen in a process. 12 refs., 2 figs., 17 tabs.

Guffey, F.D.; Cummings, R.E.

1986-03-01

258

Study on the sedimentation rate near to the radial sand ridges in the western continental shelf of South Yellow Sea  

Microsoft Academic Search

It is difficult to get the sedimentation rate of coastal sediment by normal methods for complex materials sources and active hydrodynamics, especially of the coastal relicit sediment. In this article, 14C age of humin in sediment was introduced to help to get the sedimentation rate in complex tidal sand ridge conditions. Humin is the production of ancient soil, which was

X. Lv; B. Pang; J. Song; X. Li; H. Yuan; N. Li; Y. Yang

2010-01-01

259

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

260

Racializing white drag.  

PubMed

While drag is primarily understood as a performance of gender, other performative categories such as race, class, and sexuality create drag meaning as well. Though other categories of identification are increasingly understood as essential elements of drag by performers of color, whiteness remains an unmarked category in the scholarship on drag performances by white queens. In this paper, I argue that drag by white queens must be understood as a performance of race as well as gender and that codes of gender excess are specifically constructed through the framework of these other axes of identity. This essay asks whether white performance by white queens necessarily reinscribes white supremacy through the performance of an unmarked white femininity, or might drag performance complicate (though not necessarily subvert) categories of race as well as gender? In this essay, I will suggest that camp drag performances, through the deployment of class as a crucial category of performative femininity, might indeed be a key site through which whiteness is denaturalized and its power challenged. Specifically, I will read on camp as a politicized mode of race, class and gender performance, focusing on the intersections of these categories of identity in the drag performance of Divine. PMID:15132490

Rhyne, Ragan

2004-01-01

261

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

262

Nugget-Navaho-Aztec sandstone: interaction of eolian sand sea with Andean-type volcanic arc  

SciTech Connect

The Nugget-Navaho-Aztec sand sea was deposited east of an Andean-type volcanic arc. During the early stage of eolian deposition, fluvially transported sand was concentrated in the marine littoral zone and returned inland by onshore winds from the northwest. With progressive development of the arc, the sea withdrew. Wind direction changed from northwest to northeast. Previously deposited eolian sand was transported southwestward into the volcanic arc. Proximity of the arc can be detected with great difficulty by examining eolian and underlying red-bed facies. In southern Nevada, the volcanic arc is undetectable in eolian facies, but thin sandstone beds containing volcanic clasts or weathered feldspar in the finer grained red-bed facies indicate arc volcanism; volcanic clasts are distinct in a basal conglomerate. Westward into California, the sub-Aztec Sandstone contains volcanic pebbles. The upper part of the Aztec Sandstone contains a 1 to 2-m thick volcaniclastic siltstone. Farther west, the Aztec Sandstone is interbedded with volcanic flows, ash flows, and flow breccias. These rocks might easily be mistaken for red beds in well cores or cuttings. Sand in sets of large-scale cross-beds remain virtually identical in composition and texture to sand in eolian facies of the Colorado Plateau. Where sets of eolian cross-beds lie on volcanics, the quartzose sandstone contains pebble to cobble-size volcanic clasts. Locally, cross-bed sets of yellowish-white, quartzose sandstone alternate with purplish-gray cross-bed sets containing numerous pebble to cobble-size volcanic clasts. The ability to recognize volcanic indicators within Nugget-Navaho-Aztec eolian facies is important in delineating the western margin of the back-arc eolian basin.

Marzolf, J.E.

1986-05-01

263

White light fringe modeling for the SIM CCD detector  

Microsoft Academic Search

This paper addresses the issue of the white light fringe modeling as needed for the phase information extraction with the Space Interferometry Mission (SIM) CCD detector. We developed a set of analytic expressions for the white light fringe estimation using the complex visibility phasors. The obtained expressions are valid for an arbitrary number of detector spectral channels and for an

Slava G. Turyshev

2000-01-01

264

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

265

Circular DNA from Sand Dollar Sperm.  

National Technical Information Service (NTIS)

Sand dollar sperm DNA was exposed briefly to sonic vibrations, subjected to the heating and cooling procedure and analyzed by cesium chloride density gradient centrifugation. The tracing showed that 70% of the material was rendered single-stranded as a re...

H. S. Rosenkranz G. A. Carden S. Rosenkranz

1966-01-01

266

Development of stresses in cohesionless poured sand  

Microsoft Academic Search

The pressure distribution beneath a conical sandpile, created by pouring sand from a point source onto a rough rigid support, shows a pronounced minimum below the apex ('the dip'). Recent work by the authors has attempted to explain this phe- nomenon by invoking local rules for stress propagation that depend on the local geometry, and hence on the construction history,

M. E. Cates; J.-P. Bouchaud; James Clerk

1998-01-01

267

Beach Cleaning Trials: Pendine Sands, 1983.  

National Technical Information Service (NTIS)

Techniques for the removal of stranded water-in-oil emulsion were compared in a series of trials held on Pendine sands during the period 7-11 November 1983. The report describes various techniques for scraping the beach to transfer the oily waste into tre...

P. R. Morris B. W. J. Lynch J. F. Nightingale D. H. Thomas

1984-01-01

268

Building Whales in Sand and Mind.  

ERIC Educational Resources Information Center

|Describes two-week summer workshops on evolution, adaptation, and behavior of whales, conducted for children by Cold Spring Harbor Whaling Museum (New York), and culminating in creation of life-size sand sculptures of whales. Provides selected list of periodicals, teaching materials, identification guides, records, and societies devoted to whales…

Warner, Carolyn

1980-01-01

269

Conveyor belts for transporting tar sands  

Microsoft Academic Search

A method for transporting tar sands in an open pit mine utilizing flexible belt conveyors between a receiving area and a discharge area consists of providing a conveyor belt having an upper surface layer of an elastomeric material which is flexible at low temperatures. It is substantially resistant to excess swelling when exposed to petroleum liquids containing up to 30

1976-01-01

270

Clarification of tar sands middlings water  

Microsoft Academic Search

A process is described for treating tar sands to cause flocculation or coagulation of the clays and other small solids particles present in middlings and tailings streams produced from the hot water process. The process involves the addition of an acid to the water to accelerate clarification of the water and reduce required sludge settling pond area. (1 claim)

Schutte

1974-01-01

271

Environmental impact of Alberta oil sand development  

Microsoft Academic Search

According to Esso Resources Canada Ltd.'s Environmental Impact Assessment (EIA) for its Cold Lake, Alberta, oil sands project, environmental control measures will include the clustering of wells to reduce land surface disturbances; a pipeline to the North Saskatchewan River, rather than to a recreational lake, for water supplies; the use of recycling technology to reduce total water requirements by one-half;

1980-01-01

272

Hydrocarbon cyclones in hydrophilic oil sand environments  

Microsoft Academic Search

The hydrocarbon cyclone is capable of achieving a ternary split in a range of froth treatment processes in oil sand mining and extraction. A ternary split is the maximization of water and fines rejection, while producing a high hydrocarbon recovery to the overflow and a coarse rejection to underflow that approaches 100%. The hydrocarbon cyclone takes advantage of the water-wet

D. N. Madge; J. Romero; W. L. Strand

2004-01-01

273

Sand sagebrush rangeland utilization by cattle producers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Since 1939, when the USDA purchased the Southern Plains Experimental Range (SPER), scientists of the USDA-Agricultural Research Service have been researching the appropriate uses of native mixed-grass prairie with an over story of sand sagebrush (Artemisia filifolia Torr.). This range type inhabits...

274

Developments in tar sands in 1981  

Microsoft Academic Search

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

Wennekers; J. H. N

1982-01-01

275

Hydroponic sand culture systems for mycorrhizal research  

Microsoft Academic Search

Summary Tomato plants were inoculated withGlomus fasciculatus mycorrhizal fungi while growing in sand through which recycled nutrient solution was automatically passed several times daily. Concentration of P and N in the solution were maintained at relatively low levels. Roots of inoculated plants became highly infected with mycorrhizal fungi, and yield parameters were significantly increased with inoculation over uninoculated control plants.

J. C. Ojala; W. M. Jarrell

1980-01-01

276

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

277

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

278

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

279

Alberta Oil Sands Environmental Research Program  

Microsoft Academic Search

The Alberta Oil Sands Environmental Research Program of the Governments of Canada and Alberta aims to establish baseline data on aquatic and terrestrial fauna, meteorology, and air and water quality. Air research topics include plume dispersion, chemical constitution and transformation within plumes, and the deposition of pollutants. Land system research covers subjects such as the effects of airborne emissions, soil

W. R. Macdonald; H. S. Sandhu; J. W. Bottenheim; B. Munson

1980-01-01

280

Sand Ridge Migration Apalachicola River, Florida.  

National Technical Information Service (NTIS)

The migration rate of subaqueous sand ridges was measured in two reaches of the Apalachicola River, Florida, from 25 June to 31 July 1968. At Site One, 9 miles above the river's mouth, ridge movement was irregular and inconclusive because current velociti...

R. Tittle

1969-01-01

281

Microbial diversity in Calamita ferromagnetic sand.  

PubMed

Calamita is a black ferromagnetic sand from a marine iron ore on Elba Island (Italy). Its total iron content is approximately 80% and a major fraction (63% w/w) has magnetic properties. Desiccation, ultraviolet irradiation and the high temperature induced by the thermal conductivity of iron make Calamita sand an extreme biotope. We report, for the first time, the geomicrobiological characterization of Calamita sand, which showed a low bacterial biodiversity as determined by denaturing gradient gel electrophoresis and 16S rRNA gene clone library analysis. We retrieved sequences closely affiliated with uncultured bacteria inhabiting the harshest deserts on Earth. Radiation- and desiccation-tolerant bacteria from the phyla Proteobacteria, Actinobacteria and Deinococcus-Thermus dominated the community. Heavy metal-resistant organisms, for example Variovorax sp. were also abundant. Sequences of organisms with an inferred metabolism based on lithotrophic iron oxidation were detected. The sands also contained thermophilic bacilli, which were cultivated at 60°C. These data provided important insights also into the biogeographical distribution of these organisms in the Mediterranean region. In summary, this study on Calamita helps to expand our knowledge of the biodiversity in extreme, iron-rich, environments. PMID:23761311

Perfumo, Amedea; Cockell, Charles; Elsaesser, Andreas; Marchant, Roger; Kminek, Gerhard

2011-03-14

282

Microtox™ characterization of foundry sand residuals  

Microsoft Academic Search

Although foundry residuals, consisting mostly of waste sands, represent a potentially attractive, high-volume resource for beneficial reuse applications (e.g. highway embankment construction), prospective end users are understandably concerned about unforeseen liabilities stemming from the use of these residuals. This paper, therefore, focuses on the innovative use of a microbial bioassay as a means of developing a characterization of environmental suitability

K. C Bastian; J. E Alleman

1998-01-01

283

Triaxial Compression of Sand Reinforced with Fibers  

Microsoft Academic Search

Results from drained triaxial compression tests on specimens of fiber-reinforced sand are reported. It is evident that the addition of a small amount of synthetic fibers increases the failure stress of the composite. This effect, however, is associated with a drop in initial stiffness and an increase in strain to failure. Steel fibers did not reduce initial stiffness of the

Radoslaw L. Michalowski; Jan C?erma?k

2003-01-01

284

The strength and dilatancy of sands  

Microsoft Academic Search

Extensive data of the strength and dilatancy of 17 sands in axisymmetric or plane strain at different densities and confining pressures are collated. The critical state angle of shearing resistance of soil which is shearing at con- stant volume is principally a function of mineralogy and can readily be determined experimentally within a margin of about l\\

M. D. Bolton

1986-01-01

285

The sands of time and tidal friction  

Microsoft Academic Search

Ancient Babylonian clay tablets buried for centuries beneath the sands of the desert are part of an extensive historical archive which contains vital information about the rotation of the Earth. Many are preserved, and using these seemingly crude ancient and medieval observations of eclipses, variations in the Earth's rotation can be traced back over the past 2500 years. The tidal

Leslie V. Morrison; F. Richard Stephenson

1998-01-01

286

Pyrolysis of asphalt ridge tar sand  

Microsoft Academic Search

Isothermal and nonisothermal pyrolysis experiments have been conducted on Asphalt Ridge tar sand. Oil produced from the isothermal experiments has a molecular weight of approximately 250 and has a hydrogen to carbon ratio between 1.7 and 1.9. Product oil composition varies slightly with reaction time. Results of thin layer chromatographic separation of the residual bitumen show that the concentrations of

T. F. Turner; L. G. Nickerson

1986-01-01

287

Fracturing stimulation of Frio Sand Trend  

Microsoft Academic Search

The history of techniques, fluids, chemical additives and propping agents used in fracturing wells completed in the Upper Frio Sand Trend are discussed in this paper. General reasons for fracturing a well and some requirements necessary to obtain a successful fracturing treatment are presented. How the techniques, fracturing fluid, fluid volumes, propping agent type and quantity, injection rates and chemical

P. Chisholm; J. E. Coppinger; R. R. Blount; W. T. Malone

1968-01-01

288

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

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

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

289

Process of microbial extraction of hydrocarbons from oil sands  

Microsoft Academic Search

A process is described for the separation of hydrocarbon residues from oil and tar sands by microbiological activity. Hydrocarbon residues are released from the sands by contacting with a suspension of oxidase-synthesizing, hydrocarbonmetabolizing microorganisms.

I. Rabinovitch; H. E. Worne

1982-01-01

290

Laboratory and Field Evaluation of an Underwater Sand Height Gage.  

National Technical Information Service (NTIS)

An underwater sand height gage was investigated. This instrument consisted of two transducers, one screened and one unscreened. Laboratory experimentation included static and dynamic tests with three test sands--fine, medium, and coarse. Field tests were ...

D. G. Mcgrath D. J. Swift

1972-01-01

291

Laboratory Screening of Thermal Recovery Processes for Tar Sand Triangle.  

National Technical Information Service (NTIS)

Four thermal processes (steam displacement, not-gas pyrolysis, reverse and forward combustion) were evaluated to select the most effective oil recovery process for the in situ development of the tar sand resource at Tar Sand Triangle, Utah. Reverse combus...

L. J. Romanowski K. P. Thomas

1985-01-01

292

Population Dynamics of Large Walleye in Big Sand Lake.  

National Technical Information Service (NTIS)

Walleye population parameters in Big Sand Lake, Hubbard County were estimated from 3 years of tagging and creel surveys. Estimated walleye biomass and annual yield were midrange of other North American walleye lakes. Although growth of Big Sand Lake walle...

P. C. Jacobson

1994-01-01

293

New Method for Estimation of Aeolian Sand Transport Rate Using Ceramic Sand Flux Sensor (UD-101)  

PubMed Central

In this study, a new method for the estimation of aeolian sand transport rate was developed; the method employs a ceramic sand flux sensor (UD-101). UD-101 detects wind-blown sand impacting on its surface. The method was devised by considering the results of wind tunnel experiments that were performed using a vertical sediment trap and the UD-101. Field measurements to evaluate the estimation accuracy during the prevalence of unsteady winds were performed on a flat backshore. The results showed that aeolian sand transport rates estimated using the developed method were of the same order as those estimated using the existing method for high transport rates, i.e., for transport rates greater than 0.01 kg m?1 s?1.

Udo, Keiko

2009-01-01

294

Temporal and spatial variability of ooid sand shoals: Comparison of Mississippian of Kentucky and Quaternary of Bahamas  

SciTech Connect

An examination of the lithology and topography of Andros Island, Bahamas, reveals it is a Pleistocene ooid sand shoal. A comparison with Joulters Cays (a modern ooid sand shoal directly to the north) shows that much of the original depositional topography is preserved through at least one cycle of sea level highstand and lowstand. Both the Pleistocene and the Holocene ooid sand bodies are a few kilometers to tens of kilometers wide. The total vertical relief of a single episode of Quaternary ooid sand deposition is more than 10 m and includes accumulation in tidal channels, shallow flat areas, and eolian dunes. Today, much of Andros Island is within 2 m of present sea level and is the site of a belt several kilometers wide consisting of muddy tidal flat sediments overlying an exposure surface. The site of ooid sand deposition and shoal complex formation is not continuous along shorelines, especially windward margins, but shifts abruptly along the margins of platforms as a result of minor fluctuations of sea level. Thus, it should be expected that ooid sand shoals (ancient and modern) should be in direct lateral and vertical contact with lagoons, tidal flats, and reefs. The Mississippian Slade Formation contains many of the features of Quaternary ooid sand accumulation: abrupt vertical and lateral gradations between oolitic grainstones, packstones, and lime mudstones, vertical relief of individual oolitic sedimentary packages up to 30 m (perhaps with eolian dunes) and numerous exposure surfaces of varying intensities. These characteristics suggest that this formation represents a time of rapid fluctuations of relative sea level and abrupt shifts in the sites of ooid sand shoal complexes.

Boardman, M.R. (Miami Univ., Oxford, OH (USA))

1989-08-01

295

Deep-water massive sands: nature, origin and hydrocarbon implications  

Microsoft Academic Search

Deep-water massive sands (DWMS) are here defined as very thick (>1 m) sand beds or units that are devoid of primary sedimentary structures and that occur in association with other deep-water sediments — the massive sand facies association. Following careful examination of some 70 examples of massive sands drawn from deep-water successions of all ages and lithologies, we are confident that

Dorrik A. V Stow; Melissa Johansson

2000-01-01

296

Sand–Attapulgite Clay Mixtures as a Landfill Liner  

Microsoft Academic Search

Absrtract  This paper investigates the potential use of sand–attapulgite (palygorskite) mixtures as a landfill liner. The sand and attapulgite\\u000a clay used in this study were brought from Wahiba (eastern Oman) and Al-Shuwamiyah (southern Oman), respectively. Initially\\u000a the basic properties of the sand and clay were determined. Then the attapulgite clay was added to the sand at 5, 10, 20 and\\u000a 30%

Amer A. Al-Rawas; Yahia E. A. Mohamedzein; Abdulaziz S. Al-Shabibi; Salem Al-Katheiri

2006-01-01

297

Imaging of acoustic waves in sand  

NASA Astrophysics Data System (ADS)

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

Deason, Vance A.; Telschow, Ken L.; Watson, Scott M.

2003-12-01

298

Imaging of Acoustic Waves in Sand  

SciTech Connect

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

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

2003-08-01

299

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

300

Groundwater Flow and Sand Body Interconnectedness in a Thick, Multiple-Aquifer System  

NASA Astrophysics Data System (ADS)

Many so-called sandstone aquifers are actually multiple-aquifer systems consisting of discontinuous sand bodies distributed complexly in a matrix of lower-permeability silts and clays. The arrangement and Interconnectedness of these various lithofacies strongly influence spatial patterns of hydraulic conductivity (K) and, in turn, groundwater flow and mass transport. A promising technique of estimating such patterns of K involves careful analysis of both subsurface geologic and subsurface hydrologic data. In this study the three-dimensional distribution of K was estimated for a numerical flow model of part of the Wilcox aquifer system in Texas, using K data from core samples and pumping tests and more than 100 geophysical logs. The aquifer system, which is up to 320 m thick, consists of multiple, elongate sand bodies and silts and clays deposited in a fluvial environment and is similar to many other systems found in the Gulf Coast and other sedimentary basins. The resulting deterministic-conceptual flow model demonstrates the importance and methods of incorporating geologic information in groundwater models. Flow in the aquifer is shown to be controlled not so much by K of the sands as by their continuity and Interconnectedness. Much of the aquifer system consists of large zones in which the fluvial channel-fill sands are sparse and apparently disconnected, resulting in groundwater flow rates lower by a factor of 101 to 103 than in adjacent, well-interconnected belts of fluvial channel-fill sand belts. Modeling results also raise serious doubts regarding our ability to predict regional scale flow and mass transport in complex aquifers such as the Wilcox, using current technology. Though sand body Interconnectedness is critically important, it is also very difficult to estimate. One or two well-connected sands among a system of otherwise disconnected sands can completely alter a velocity field. This is particularly true if the sands are connected vertically and nonzero vertical hydraulic gradients exist. Because the model is three-dimensional, sensitivity of hydraulic head to heterogeneity or Interconnectedness is much less than normally observed in two-dimensional models, and therefore heads computed by the model give little to no indication of the location of well-interconnected zones. Thus such zones can easily go undetected, even in carefully calibrated models which yield reasonably accurate hydraulic heads. This is a significant point for modeling of solute transport.

Fogg, Graham E.

1986-05-01

301

WMO Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS): Research Implementation Status  

NASA Astrophysics Data System (ADS)

Strong winds cause lifting of large amounts of sand and dust from bare, dry soils into the atmosphere. For countries in and downwind of arid regions, airborne sand and dust presents serious risks to the environment, property and human health. Impacts on health include respiratory and cardio-vascular problems, eye infections and in some regions, diseases such as meningitis and valley fever. Dust can efficiently carry irritating spores, bacteria, viruses and persistent organic pollutants. It can also efficiently transport nutrients to parts of the world oceans and affect marine biomass production. Other impacts include negative effects on the ground transport, aviation, agriculture and visibility. The Inter-governmental Panel on Climate Change (IPCC) recognizes dust as a major component of the atmospheric aerosol that is an essential climate variable. Dust aerosol has important effects on weather through feedback on atmospheric dynamics, clouds and precipitation formation. Approximately 15 centres around the world provide sand and dust research operational forecasts. Many are operated by national meteorological services of the World Meteorological Organization (WMO). Sand and dust storm models can substantially reduce risk by providing dust concentration predictions for several days in advance. Numerical weather prediction systems that drive these models use complex parameterizations and assimilation of satellite, and surface-based observations to predict winds, clouds, precipitation and dust mobilization, transport, and removal from the atmosphere. Sand and dust forecast products contribute to the mitigation and reduction of risk through research based advances in understanding and forecasting products. Observations of sand and dust are made by many agencies and some of them are being coordinated globally through the WMO Global Atmosphere Watch (GAW) programme. In 2006, WMO and partners initiated the implementation of the Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS) in order to improve the capabilities of countries affected by dust to reduce risks associated with airborne sand and dust. This project is in response to the desire of more than 40 WMO member countries to improve capabilities for more reliable sand and dust storm forecasts. The project has strong crosscutting features: it relies on real-time delivery of products; it integrates research communities (modelling, observation groups, and effects) and communities of practice (e.g. medical, aeronautical, agricultural users). There are two already established SDS-WAS nodes (Asian and North-Africa-Europe-Middle East) that coordinate implementation of the project objectives at regional levels. This presentation will review current status and future steps in the project implementation.

Nickovic, Slobodan; Barrie, Leonard

2010-05-01

302

Great Canadian Oil Sands experience in the commercial processing of Athabasca Tar Sands  

Microsoft Academic Search

A brief review is given of the history of the Great Canadian Oil Sands (G.C.O.S.) project to recover 45,000 bpd of synthetic crude oil from the Athabasca Tar Sands by open pit mining, hot water extraction, coking, and hydrorefining. This paper then discusses the startup and initial operation of the G.C.O.S. plant. Emphasis is directed toward actual vs. design performance

G. F. Andrews; H. M. Lewis; E. W. Dobson

1968-01-01

303

Sand dollar: a weight belt for the juvenile.  

PubMed

Juvenile sand dollars (Dendraster excentricus) selectively ingest heavy sand grains from the substrate and store them in an intestinal diverticulum which may function as a weight belt, assisting the young animal to remain in the shifting sandy environment. The sand disappears from the diverticulum when the animal reaches the length of 30 millimeters. PMID:17769829

Chia, F S

1973-07-01

304

Sand Dollar: A Weight Belt for the Juvenile  

Microsoft Academic Search

Juvenile sand dollars (Dendraster excentricus) selectively ingest heavy sand grains from the substrate and store them in an intestinal diverticulum which may function as a weight belt, assisting the young animal to remain in the shifting sandy environment. The sand disappears from the diverticulum when the animal reaches the length of 30 millimeters.

Fu-Shiang Chia

1973-01-01

305

Impact on Soft Sand: Void Collapse and Jet Formation  

Microsoft Academic Search

Very fine sand is prepared in a well-defined and fully decompactified state by letting gas bubble through it. After turning off the gas stream, a steel ball is dropped on the sand. On impact of the ball, sand is blown away in all directions (``splash'') and an impact crater forms. When this cavity collapses, a granular jet emerges and is

Detlef Lohse; Raymond Bergmann; René Mikkelsen; Christiaan Zeilstra; Devaraj van der Meer; Michel Versluis; Ko van der Weele; Martin van der Hoef; Hans Kuipers

2004-01-01

306

Dynamic Shear Moduli and Damping Ratios for Dry Sands.  

National Technical Information Service (NTIS)

Using the Torsional Simple Shear Device, the authors investigated the equivalent dynamic shear moduli G sub eq and the damping ratio lambda for Ottawa sand, Del Monte sand, Golden Gardens and Seward Park sands. Based on their experimental findings the aut...

M. A. Serif I. Ishibashi

1976-01-01

307

Numerical simulation of wind sand movement in straw checkerboard barriers.  

PubMed

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

Huang, Ning; Xia, Xianpan; Tong, Ding

2013-09-13

308

A RELIC SAND WAVE FIELD IN A TIDAL CHANNEL  

Microsoft Academic Search

A sand wave field in the eastern flood channel of Moriches Inlet was monitored for eight weeks during the summer of 2005. Bathymetric data show sand waves which are 15 m long and 39 cm tall with shallow slip faces. These sand waves remained stationary over the eight week study. Analysis based on work by van Rijn (1984) and Yalin

Shelley J. Whitmeyer; Duncan FitzGerald

2007-01-01

309

Experimental Study of Novel Micro Sands Flocculation Technology  

Microsoft Academic Search

Novel micro sands flocculation technology was developed, such as optimization of design, additive combination, hydrodynamic condition and participation velocity. The results showed that micro sands flocculation technology can treat wastewater better than normal technology. Some optimum parameters in micro sands flocculation technology were obtained to support its commercial application.

Chen Wei; Liu Xi; Fan Yuehua; Zhang Shun

2009-01-01

310

Well completion process for formations with unconsolidated sands  

DOEpatents

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

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

2003-04-29

311

Fingered preferential flow in unsaturated homogeneous coarse sands  

Microsoft Academic Search

The occurrence of fingered preferential flow depends on both flow and porous media characteristics. The boundary condition of un­ saturated infiltration has been investigated to assess whether it produces unstable wetting in homogeneous coarse sands. Laboratory tracer experi­ ments were conducted in two coarse sand materials; for each sand material two initial conditions of air dry and field capacity were

M. S. BABEL; R. LOOF; A. DAS GUPTA

1995-01-01

312

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

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

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

313

The origin, classification and modelling of sand banks and ridges  

Microsoft Academic Search

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

Keith R Dyer; David A Huntley

1999-01-01

314

Trials with Artificial Sand Products in Steel-Foundries.  

National Technical Information Service (NTIS)

Today molds for steel castings are mainly consisting of cold resins bonded quartz sand, which may cause silicosis when the workmen inhale dust-laden air in the foundry. By using corundum sand instead of quartz sand the risk of silicoses can be avoided. Co...

F. Heczko

1979-01-01

315

Erosion Potential of Various Golf Course Bunker Sands  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sand bunkers are principal golf course features adding aesthetic beauty and challenge for golfers. Bunkers often require substantial resources for proper maintenance particularly where sand is installed on severe slopes in humid climates subject to occasional heavy rainfall. Numerous sands are comme...

316

Method and apparatus for hydrocarbon recovery from tar sands  

Microsoft Academic Search

A method and apparatus for utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000.degree. F. in a burner to remove residual char and

James D. Westhoff; Arnold E. Harak

1989-01-01

317

Method and apparatus for hydrocarbon recovery from tar sands  

Microsoft Academic Search

A method and apparatus or utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000°F in a burner to remove residual char nd produce

J. D. Westhoff; A. E. Harak

1989-01-01

318

Method and apparatus for hydrocarbon recovery from tar sands  

Microsoft Academic Search

A method and apparatus for utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000\\/degree\\/F in a burner to remove residual char and produce

J. D. Westhoff; A. E. Harak

1988-01-01

319

Pyrolysis of Utah tar sands: products and kinetics  

Microsoft Academic Search

The development of successful in-situ thermal recovery techniques for the Utah tar sands requires a knowledge and consideration of the pyrolytic behavior of these bituminous materials. Tar sands from four major Utah deposits, Northwest Asphalt Ridge, Tar Sand Triangle, P.R. Spring, Sunnyside, and from one Canadian deposit, Athabasca, were subjected to pyrolysis, in an inert atmosphere, at temperatures ranging from

R. V. Barbour; S. M. Dorrence; T. L. Vollmer; J. D. Harris

1976-01-01

320

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

SciTech Connect

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

Not Available

1993-05-01

321

Reuse of waste cutting sand at Lawrence Livermore National Laboratory  

Microsoft Academic Search

Lawrence Livermore National Laboratory (LLNL) examined the waste stream from a water jet cutting operation, to evaluate the possible reuse of waste garnet sand. The sand is a cutting agent used to shape a variety of materials, including metals. Nearly 70,000 pounds of waste sand is generated annually by the cutting operation. The Environmental Protection Department evaluated two potential reuses

1998-01-01

322

Unconsolidated Sand Stabilization Through Wellbore Stress State Control  

Microsoft Academic Search

Two methods are presented for controlling wellbore stress state in order to stabilize unconsolidated sands. One method is the application of elevated drilling fluid weight to prevent dilation and\\/or shear\\/crushing of sand grains surrounding the wellbore. Instabilities resulting from such formation failure would be expected to increase the likelihood for sand production. Means are provided for determining mud weight required

George Suman Jr; G. O. Jr

1975-01-01

323

Vetiver System for Sand Dune Stabilization A Vietnamese Experience  

Microsoft Academic Search

Sand dunes occupy more than 70,000 ha along the coast of Central Vietnam, being the sources of such natural disasters as sand storm, sand flow\\/flash flood etc., that eat either slowly or catastrophically villages and fields. This has been surveyed by a team of geologists from the Research Institute of Geology and Mineral Resources (RIGMR), who also looked for remedial

324

Enhancing Oil Production by Helical Hydraulic Sand-Blasting  

Microsoft Academic Search

The helical hydraulic sand-blasting slotting technology is a new development of the traditional hydraulic sand-blasting slotting technology. The original nozzle gun movement control system was replaced with a helical slid rail, and thus the application was extended to directional and horizontal wells. Experiments were conducted to study the feasibility abrasive water jet slotting sand prevention tubes. The effects of slotting

G. Li; J. Song; J. Niu; R. Tang; Z. Huang

2007-01-01

325

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

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

326

Sand, die and investment cast parts via the SLS selective laser sintering process  

NASA Astrophysics Data System (ADS)

Complex three-dimensional parts can be manufactured directly from CAD data using rapid prototyping processes. SLS selective laser sintering is a rapid prototyping process developed at the University of Texas at Austin and commercialized by DTM Corporation. SLS parts are constructed layer by layer from powdered materials using laser energy to melt CAD specified cross sections. Polymer, metal, and ceramic powders are all potential candidate materials for this process. In this paper the fabrication of complex metal parts rapidly using the investment, die and sand casting technologies in conjunction with the selective laser sintering process are being explained and discussed. TrueForm and polycarbonate were used for investment casting, while RapidSteel metal mould inserts were used for the die casting trials. Two different SandForm materials, zircon and silica sand, are currently available for the direct production of sand moulds and cores. The flexible and versatile selective laser sintering process all these materials on one single sinterstation. Material can be changed fast and easily between two different builds.

van de Crommert, Simon; Seitz, Sandra; Esser, Klaus K.; McAlea, Kevin

1997-09-01

327

Interior of Left Powerhouse showing the Whiting (Company's) "Tiger" crane ...  

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

Interior of Left Powerhouse showing the Whiting (Company's) "Tiger" crane with a capacity of 350 tons, looking west. Note the terrazzo floor below depicting a Francis turbine. - Columbia Basin Project, Grand Coulee Dam Powerplant Complex, Grand Coulee, Grant County, WA

328

White Blood Cell Disorders  

MedlinePLUS

... Subjects Women's Health Issues Chapters in Blood Disorders Biology of Blood Symptoms and Diagnosis of Blood Disorders ... and digest the harmful organism or substance (see Biology of the Immune System: White blood cells and ...

329

White coat hypertension and white coat effect similarities and differences  

Microsoft Academic Search

The rise in blood pressure (BP) associated with clinical visit (white coat effect) may be one basic mechanism of white coat hypertension (persistently raised clinic BP together with a normal BP outside the clinic), but the relations between white coat hypertension, white coat effect, and target organ damage have not yet been assessed on large populations. Thus, we performed 24-h

Paolo Verdecchia; Giuseppe Schillaci; Claudia Borgioni; Antonella Ciucci; Ivano Zampi; Roberto Gattobigio; Nicola Sacchi; Carlo Porcellati

1995-01-01

330

Inbreeding in white tigers  

Microsoft Academic Search

One of the problems of breeding of endangered species in captivity is inbreeding. An exemplary illustration is the inbreeding\\u000a in the white tigers of Rewa. Genealogies and other relevant information on white tigers were collected from four Zoological\\u000a Parks to investigate whether matings between close relatives were responsible for the reduction in litter size and increase\\u000a in early mortality which

A K Roychoudhury; K S Sankhala

1979-01-01

331

Mycorrhizal inoculum potentials of pure reclamation materials and revegetated tailing sands from the Canadian oil sand industry  

Microsoft Academic Search

Recent improvements in the management of oil sand tailings used by the Canadian oil sand industry have resulted in the production of composite tailing sands (CT): a new challenging material for reclamation work. Jack pine (Pinus banksiana Lamb.), hybrid poplar (Populus deltoides Bartr. ex Marsh. ×Populus nigra L.) and red clover (Trifolium pratense L.) plants were used in an 8-week

G. Bois; Y. Piché; M. Y. P. Fung; D. P. Khasa

2005-01-01

332

Detecting oil sands process-affected waters in the Alberta oil sands region using synchronous fluorescence spectroscopy  

Microsoft Academic Search

Large volumes of oil sands process-affected waters (OSPW) are produced during the extraction of bitumen from oil sand. There are approximately 109m3 of OSPW currently being stored in settling basins on oil sands mining sites in Northern Alberta. Developers plan to create artificial lakes with OSPW and it is expected that this water may eventually enter the environment. This study

Richard J. Kavanagh; B. Kent Burnison; Richard A. Frank; Keith R. Solomon; Glen Van Der Kraak

2009-01-01

333

Origin of Titan's dunes: noncohesive sand in bidirectional winds or sticky sand in unidirectional winds?  

NASA Astrophysics Data System (ADS)

Eolian dunes occur on Earth, Venus, Mars, and Titan, distinguishing them as one of the more widespread landforms in the solar system. On Earth, unidirectional winds blowing over loose, noncohesive sand produce crescentic-shaped dunes with crests oriented normal to the sand-transport direction (transverse dunes), but roughly half of Earth's large deserts are covered with longer-crested dunes (linear dunes) that are commonly oriented parallel or oblique to the resultant sand-transport vector (longitudinal dunes and oblique dunes, respectively). Such linear dunes form in at least two situations: (1) directionally bimodal winds blowing over loose sand, and (2) unimodal winds blowing over sediment that is vegetated, cohesive, sheltered by upwind topography, or otherwise locally stabilized. This study documents an example (Qaidam Basin, China) where a downwind increase in sediment cohesiveness (due to salt and mud incorporated from the local land surface) causes dunes to change orientation from transverse to longitudinal, and the work presents a compilation of related situations where stabilization of dune sediment has been reported to produce linear dunes. This family of stabilized dunes functions dynamically as self-extending "sand-shadow" or lee dunes. Loose sediment accumulates locally on these dunes, where it becomes stabilized, thereby allowing the dune itself to function as an obstacle that induces subsequent deposition farther downwind. Linear dunes on Titan previously have been interpreted as forming in the first situation listed above: bimodal winds blowing over loose sand. Because Titan's sand is believed to be composed of hydrocarbons or nitriles, however, the hypothesized loose, non-sticky nature of the sand has surprised researchers. In addition, the previous hypothesis of bimodal winds requires that north-south tidal flow be stronger than west-east zonal flow, which also was unexpected. The new hypothesis presented here—that Titan's dunes formed by unidirectional winds blowing over cohesive or sticky sand—resolves these two puzzles, cannot be ruled out with existing observations, and has grossly different implications regarding Titan's sediment properties, surface moisture, and wind regime. Satellite image of dunes in the Qaidam Basin, China. Change in sediment properties causes a change from transverse to longitudinal orientation of the dunes. Transverse dunes are higher in elevation than the longitudinal dunes and composed of noncohesive sand. Longitudinal dunes are cemented with silt, clay, and salt acquired locally.

Rubin, D. M.

2009-12-01

334

Retention behavior of dilute polymers in oil sands  

SciTech Connect

Adequate mobility control between fluid banks is a pertinent factor in the successful application of secondary and tertiary oil recovery processes. Favorable mobilities can be obtained by increasing the viscosity or reducing the permeability to the displacing fluid phase. Polyacrylamide and oio-polymers have proved to be useful for these purposes. These polymers increase the water viscosity substantially at low concentrations. The resulting reduced mobility of the displacing phase suppresses the fingering phenomenon and improves piston-like displacement. However, the structural complexity of these polymers coupled with the complexity of the flow channels in the porous medium cause part of these polymers to be retained in the reservoir as the displacing fluid from advances, thereby causing a reduction in the concentration of the polymer solution and consequently a loss of mobility control. In addition to the mechanical filtering, adsorption on the grain surfaces reduce the polymer concentration in the displacing fluid. Behavior of polyacrylamide polymers has been studied extensively. Susceptibility of these polymers to salinity, pH, shear, temperature, etc., is well documented. Mechanical entrapment, retention, degradation and adsorption behavior on porous media, including fired Berea sandstone, bead packs and Ottawa sand have been reported. The present study investigates the adsorption and trapping of polymers in flow experiments through unconsolidated oil field sands. Effects of particle size and mineral content have been studied. Effect of a surfactant slug on polymer-rock interaction is also reported. Corroborative studies have been conducted to study the pressure behavior and high tertiary oil recovery in surfactant dilute-polymer systems.

Kikani, J.; Somerton, W.H.

1988-05-01

335

Discrimination and psychological distress: does Whiteness matter for Arab Americans?  

PubMed

The white racial category in the U.S. encompasses persons who have Arab ancestry. Arab Americans, however, have always occupied a precarious position in relationship to Whiteness. This study examined differences in reporting racial/ethnic discrimination among Arab Americans. It also investigated whether and how the association between discrimination and psychological distress varies by characteristics that capture an Arab American's proximity to/distance from Whiteness. We used data from the Detroit Arab American Study (2003; n = 1016), which includes measures of discrimination and the Kessler-10 scale of psychological distress. A series of logistic regression models were specified to test the discrimination-psychological distress association, stratified by five measures that capture Whiteness--subjective racial identification, religion, skin color, ethnic centrality, and residence in the ethnic enclave. Discrimination was more frequently reported by Muslim Arab Americans, those who racially identify as non-white, and who live in the ethnic enclave. Conversely, the association between discrimination and psychological distress was stronger for Christian Arab Americans, those who racially identify as white, who have dark skin color, and who live outside the ethnic enclave. Even though Arab Americans who occupy an identity location close to Whiteness are less subjected to discrimination, they are more negatively affected by it. The findings illuminate the complex pathways through which discrimination associates with psychological distress among 'white' immigrants. Further research on discrimination and health among Arab Americans can help unpack the white racial category and deconstruct Whiteness. PMID:22901668

Abdulrahim, Sawsan; James, Sherman A; Yamout, Rouham; Baker, Wayne

2012-08-08

336

Laboratory Experiments of Sand Ripples with Bimodal Size Distributions Under Asymmetric Oscillatory Flows  

NASA Astrophysics Data System (ADS)

The dynamics of sand ripples are vital to understanding numerous coastal processes such as sediment transport, wave attenuation, boundary layer development, and seafloor acoustic properties. Though significant laboratory research has been conducted to elucidate oscillatory flow morphodynamics under various constant and transient forcing conditions, the majority of the previous experiments were conducted only for beds with unimodal size distributions of sediment. Recent oscillatory flow experiments as well as past laboratory observations in uniform flows suggest that the presence of heterogeneous size sand compositions may significantly impact ripple morphology, resulting in a variety of observable effects (e.g., sediment sorting, bed armoring, and altered transport rates). Experimental work was conducted in a small oscillatory flow tunnel at the Sediment Dynamics Laboratory at the Naval Research Laboratory, Stennis Space Center. Three different monochromatic oscillatory forcings having velocity asymmetry were used to study sand ripple dynamics over five bimodal and two unimodal sediment beds. The seven different mixtures were composed using two unimodal sands of different colors (blue/white) and median grain diameters (d=0.31 mm / d=0.65 mm) combined into various mixtures by mass (i.e., 0/100; 10/90; 25/75; 50/50; 75/25; 90/10; and 100/0 which denotes mass percentage of blue/white sand, respectively, within each mixture). High-definition video of the sediment bed profile was acquired in conjunction with sediment trap measurements to resolve differences in ripple geometries, migration and evolution rates due to the different sediment mixtures and flow conditions. Observational findings clearly illustrate sediment stratification within ripple crests and the depth of the active mixing layer in addition to supporting sediment sorting in previous research on symmetric oscillatory flows in which the larger grains collect on top of ripple crests and smaller grains in the troughs. Preliminary quantitative results illuminate variations in equilibrium ripple geometry, ripple migration rates, and transition time scales between equilibrium states, all as functions of the sediment size mixture and flow forcing.

Calantoni, J.; Landry, B. J.

2010-12-01

337

Fracturing yields oil from poorly consolidated sands  

SciTech Connect

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

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

1984-05-01

338

Comparison of SAND-II and FERRET  

SciTech Connect

A comparison was made of the advantages and disadvantages of two codes, SAND-II and FERRET, for determining the neutron flux spectrum and uncertainty from experimental dosimeter measurements as anticipated in the FFTF Reactor Characterization Program. This comparison involved an examination of the methodology and the operational performance of each code. The merits of each code were identified with respect to theoretical basis, directness of method, solution uniqueness, subjective influences, and sensitivity to various input parameters.

Wootan, D.W.; Schmittroth, F.

1981-01-01

339

Development of Stresses in Cohesionless Poured Sand  

Microsoft Academic Search

The pressure distribution beneath a conical sandpile, created by pouring sand\\u000afrom a point source onto a rough rigid support, shows a pronounced minimum\\u000abelow the apex (`the dip'). Recent work of the authors has attempted to explain\\u000athis phenomenon by invoking local rules for stress propagation that depend on\\u000athe local geometry, and hence on the construction history, of

M. E. Cates; J. P. Wittmer; J.-P. Bouchaud; P. Claudin

1998-01-01

340

Solvent extraction of Southern US tar sands  

SciTech Connect

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

Penney, W.R.

1990-01-01

341

A constitutive model for frozen sand  

SciTech Connect

An elasto-viscoplastic constitutive model for frozen sand is proposed based on the elasto-viscoplasticity theory incorporating the new time measure. The proposed model can describe a number of features of the mechanical behavior of the medium, such as rate sensitivity and strain softening under the triaxial compression test loading conditions. The effects of temperature, ambient pressure and the concentration of soil particles are also discussed.

Adachi, T. (Kyoto Univ. (Japan)); Oka, F. (Gifu Univ. (Japan)); Poorooshasb, H.B. (Concordia Univ., Loyola Campus, Montreal, PQ (Canada))

1990-09-01

342

Failure Caused by Breaching in Subaqueous Sand  

Microsoft Academic Search

Breaching can generate sustained turbidity flows in submarine canyon heads or delta mouths; it is caused by shear dilation. We conduct flume experiments and analyze pore pressure changes due to shear dilation during breaching. We deposit and consolidate fine-grained sand 9cm deep and 6cm long at one end of a 29cm long water-filled tank placed on flat surface. Breaching is

Y. You; P. B. Flemings; D. C. Mohrig

2009-01-01

343

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

344

Variable aspect ratio method in the Xu–White model for shear-wave velocity estimation  

NASA Astrophysics Data System (ADS)

Shear-wave velocity logs are useful for various seismic interpretation applications, including bright spot analyses, amplitude-versus-offset analyses and multicomponent seismic interpretations. This paper presents a method for predicting the shear-wave velocity of argillaceous sandstone from conventional log data and experimental data, based on Gassmann's equations and the Xu–White model. This variable aspect ratio method takes into account all the influences of the matrix nature, shale content, porosity size and pore geometry, and the properties of pore fluid of argillaceous sandstone, replacing the fixed aspect ratio assumption in the conventional Xu–White model. To achieve this, we first use the Xu–White model to derive the bulk and shear modulus of dry rock in a sand–clay mixture. Secondly, we use Gassmann's equations to calculate the fluid-saturated elastic properties, including compressional and shear-wave velocities. Finally, we use the variable aspect ratio method to estimate the shear-wave velocity. The numerical results indicate that the variable aspect ratio method provides an important improvement in the application of the Xu–White model for sand–clay mixtures and allows for a variable aspect ratio log to be introduced into the Xu–White model instead of the constant aspect ratio assumption. This method shows a significant improvement in predicting velocities over the conventional Xu–White model.

Bai, Jun-Yu; Yue, Cheng-Qi; Liang, Yi-Qiang; Song, Zhi-Xiang; Ling, Su; Zhang, Yang; Wu, Wei

2013-06-01

345

The saltations of different sized particles in aeolian sand transport  

NASA Astrophysics Data System (ADS)

Wind tunnel experiments were performed in order to investigate the effect of mixing on the aeolian transport of sands with different grain sizes. Two types of sand with different grain size distributions and an equal-mass binary mixture of these sands were used. Comparing the gradients of their measured mass flux profiles and some published profiles for mixed sand transport with those for nearly uniform sand transport, it was found that for both of these types of sand bed, the negative gradient of the mass flux profile on a log-linear plot varies with the mass averaged grain size of the sand bed according to the same power law. Hence it can be deduced that, during the aeolian transport of mixed sand beds, the mean vertical ejection speeds of different sized grains are nearly identical to that for the transport of monospecific-sized sand with the same mass averaged grain size. Theoretical analysis was undertaken to explore the characteristics of ejections of different sized grains during the aeolian transport of sand with mixed-size grains. It is proposed that the mean ejection angles and the mean ejection speeds for sand grains of different sizes are nearly identical and are equivalent to that for monospecific-sized sand with the same mass averaged grain size. It was also evident that the ratio between the transport rate of each grain size group expressed as the fraction in the whole transport rate and its mass fraction in the mixed-size sand is a combined consequence of both the wind effect on the mean saltation distance of different sized grains and the effect of the mass fraction of each grain size group in the original mixture on its ejection potential responding to an impact of a saltating sand grain.

Xing, Mao; Wu, Chuanyu; Adams, Michael J.

2011-11-01

346

Blending foundry sands with soil: Effect on dehydrogenase activity.  

PubMed

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

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

2005-06-21

347

Heaping Instabilities in Vertically Shaken Sand  

NASA Astrophysics Data System (ADS)

We present experimental studies and PIV analysis of granular convection and the formation of heaps in vertically shaken sand. The sand is contained in a quasi two-dimensional, glass or Plexiglas rectangular cell (25.4 cm x 20.3 cm x 1.5 cm lwh) vibrated sinusoidally with a mechanical shaker at frequencies ~ 10 Hz and amplitudes ~ 1 cm. Localized heaping develops as granular convection begins. While the dimensionless acceleration (? = a ?^2 /g) largely determines the time scale for the formation of the heap, the surface properties of the granular material has an enormous impact on the internal convection patterns and the magnitude of the local slope. Specifically, high-friction ``rough'' sand forms a large heap -- approaching 30^o -- under moderate accelerations (? ~ 1.4) while the surface of the heap formed by low-friction glass beads remains nearly flat. The location of the top of the heap within the cell can be tracked over periods of several days and exhibits a ``random'' side-to-side motion resembling a random walker in a quartic potential.

Hartley, R. R.; Behringer, R. P.

1999-11-01

348

Effects of starvation on protein synthesis and nucleic acid metabolism in the muscle of the barred sand bass Paralabrax nebulifer  

SciTech Connect

Starvation induced different protein synthesis responses in red and white muscle of the barred sand bass Paralabrax nebulifer. Red muscle had /sup 14/C-leucine incorporation rates into total protein which were several times higher than white muscle in both the fed and starved states. Muscle was separated into a myofibrillar fraction consisting of the structural proteins and a sarcoplasmic fraction consisting of soluble proteins. Synthesis of the myofibrillar fraction of white muscle decreased by 90%, while red muscle myofibrillar synthesis remained essentially unchanged. Changes in the labeling of several enzymes purified from the sarcoplasmic fraction were different even though the overall loss of enzyme activity was similar, suggesting that changes in synthesis rates were important in maintaining appropriate relative enzyme concentrations.

Lowery, M.S.

1987-01-01

349

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

350

Laboratory measurement of electrification of wind-blown sands and simulation of its effect on sand saltation movement  

NASA Astrophysics Data System (ADS)

This article presents a measurement of electrification generated by wind-blown sands in a field wind tunnel and a numerical methodology to simulate the effect of electrification on the sand saltation movement after the mutual couple interaction between the sand movement and the wind flow is taken into account. The measured data of electric charge on the "uniform" sands in the wind-tunnel tests show that the sign of electric charge, either negative or positive, is mainly dependent on the diameter size of sand particles, i.e., negative charge is gained when the diameter is smaller than 250 ?m and positive charge is obtained if the diameter is larger than 500 ?m, and that for both "uniform" and mixed sands, the average charge-to-mass ratio decreases with increasing the wind velocity, and increases with height from sand bed. Meanwhile, the measurement of electric field in wind-sand cloud related to the electric charge displays that the magnitude of electric field increases generally as the wind velocity and the height increase, and the direction of the field is always upwardly vertical to the Earth's surface, which is opposite to that of the fair-weather field. In order to exhibit the effect of electrification on sand saltation movement, a theoretical model by considering the mutual coupling interaction between wind flow and sand movement is proposed after the electric force exerted on the moving sands is considered. Through solving the nonlinear coupling dynamic equations by a proposed program, the effect of electrification on sand saltation motion, e.g., trajectory, is discussed quantitatively. After that, its effect on wind-sand transport flux, sand ejecta flux, and wind profile is also displayed. The results show that the prediction for the Bagnold's kink is good agreement with the measurement in literature.

Zheng, Xiao Jing; Huang, Ning; Zhou, You-He

2003-05-01

351

Large-scale hydrocarbon-driven sand injection in the Paleogene of the North Sea  

Microsoft Academic Search

The detailed study of many diagenetic carbonates (concretions, cemented bioturbation burrows etc.) and dykes of a large-scale sandstone injection complex, which are preserved in a cored early Eocene section recovered from the South Viking Graben (North Sea), provides evidence for the dyke emplacement by gas-driven sand injection and coeval methane seepage. The morphology, chemistry of fluid inclusions, isotopic signature (?13C

Davide Duranti; Adriano Mazzini

2005-01-01

352

Microwve inducdd catalytic decomposition of some alberta oil sands and bitumens  

Microsoft Academic Search

The processing of oil sands materials and upgrading of bitumens present a variety of problems for conventional technologies.\\u000a This article describes a preliminary study of the concept of using microwave induced catalytic techniques to decompose the\\u000a complex and viscous hydrocarbon compounds contained in these materials to allow efficient extraction of volatile and economically\\u000a useful organic products such as C2 and

M. C. Depew; S. Lem; J. K. S. Wan

1991-01-01

353

Illinois Studies of the Culturally Disadvantaged. Job Perceptions Among Black and White Adolescents and the Hardcore Unemployed.  

National Technical Information Service (NTIS)

An instrument developed and used to measure and compare the job perceptions of various black and white social groups found differences between blacks and whites which indicated that job level, job complexity, job variability, and subjective job evaluation...

H. C. Triandis J. M. Feldman W. M. Harvey

1971-01-01

354

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

355

Process of organic material extraction from bituminous sands or oil bearing sands  

SciTech Connect

A cold water diluent process for recovering oil from bituminous or conventional oil sands thereafter referred to as oil sands is described including the steps of: (a) conditioning the optionally crushed oil sand, by diluent slurrying in a rotating drum; (b) introducing the slurry into the lower part of one or successively two helical, classifier type, separators, to be scrubbed in counter-current with diluent, fed into the upper part of the separator(s) by spraying; (c) withdrawing from the lower part of the first helical separator a rich oil-diluent product; (d) refining by a conventional method, this low viscosity oil-diluent product; (e) feeding the sand, withdrawn in the upper part of the second helical separator, into a separation column to settle; (f) introducing, into the column, diluent, under the diluent-water media interface and a mixture of slightly alkaline, not dispersing clay, recycle and fresh water, and process control additives; (g) withdrawing from the column: a diluent stream with little oil in the upper part; an aqueous impurified middling, in the opposite part of diluent and water inlets and between them; a sand settled in the bottom; (h) recycling the diluent with little oil to the first scrubbing stage; (i) treating the aqueous medium by conventional method to obtain: remanent oil and diluent, if any; clarified water to recycling; a fine waste; (j) disposing, or, if necessary, finally cleaning the sand by scrubbing in a helical, classifier type, separator, in counter-current with water and with process control additives.

Stoian, A.; Panaitescu, N.; Tuliu, M.

1987-10-27

356

Lowering the glycemic index of white bread using a white bean extract  

Microsoft Academic Search

BACKGROUND: Phase 2® is a dietary supplement derived from the common white kidney bean (Phaseolus vulgaris). Phase 2 has been shown to inhibit alpha-amylase, the complex carbohydrate digesting enzyme, in vitro. The inhibition of alpha-amylase may result in the lowering of the effective Glycemic Index (GI) of certain foods. The objective of this study was to determine whether the addition

Jay K Udani; Betsy B Singh; Marilyn L Barrett; Harry G Preuss

2009-01-01

357

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

358

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

359

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

360

Convergent Evolution and Divergent Selection: Lizards at the White Sands Ecotone  

Microsoft Academic Search

Ecological transition zones, where organismal pheno- types result from a delicate balance between selection and migration, highlight the interplay of local adaptation and gene flow. Here, I study the response of an entire species assemblage to natural selection across a common ecotone. Three lizard species, distributed along a dramatic environmental gradient in substrate color, display conver- gent adaptation of blanched

2006-01-01

361

Precessive sand ripples in intense steady shear flows  

NASA Astrophysics Data System (ADS)

We describe experimental observations of fully developed, large-amplitude bars under the action of a shearing fluid. The experiments were performed in an annular tank filled with water and sheared above by a steady motor source. The same steady shearing flow can produce a variety of different erodible bed manifestations: advective or precessive bars, which refer to bar structures with global regularity and a near-steady precession velocity; interactive bars, the structure of which depends on local rearrangements, which are in turn a response to complex background topography; and dispersive bars, which are created when an initially isolated mound of sand evolves into a train of sand ripples. Of these, the most amenable to analysis are the precessive bars. For precession bars, we find that the skin depth, which is the nondimensionalized mean-field transport rate, grows exponentially as a function of the shear velocity. From this, we arrive at an analytical expression that approximates the precession speed of the bars as a function of shear velocity. We use this to obtain a formula for sediment transport rate. However, in intense flows, the bars can get large engendering boundary layer separation, leading to a different dynamic for bar formation and evolution. Numerical flow calculations over an experimentally obtained set of precessive bars are presented and show that classical parametrizations of mass flux in terms of bottom gradients have shortcomings. Within the range of shear rates considered, a quantity that does not change appreciably in time is the aspect ratio, which is defined as the ratio of the average bar amplitude, with respect to a mean depth, to the average bar length.

Restrepo, Juan M.; Moulton, Derek E.; Uys, Hermann

2011-03-01

362

Continental scale fluvial sediment recycling as expressed by a constant cosmogenic nuclide ratio in sand supplied from the Nile River over the last 2.5 Ma  

NASA Astrophysics Data System (ADS)

Quartz in the eastern Mediterranean coastal plain is supplied through an extended transport system, which includes the Nile River, east Mediterranean longshore currents, and inland (Aeolian) sand transport. During this long and complex transport system, quartz grains are dosed with cosmogenic nuclides. While the concentrations of 26Al and 10Be, and their ratio, in modern sand deposited along the coast of the eastern Mediterranean reflect the combined effect of sand exposure and burial during transport, the concentrations of these nuclides in ancient buried sand are the result of decay of such an initial dosing. Samples of modern exposed sand (n=3) collected from the coastal plain of Israel yield an average 26Al/10Be ratio of 4.8±0.2, significantly lower than the expected ratio of 6.8 for exposed quartz grains at the surface. This ratio is equivalent to an apparent burial period of ~600 ka. A ratio of 4.5±0.3 was measured in a Pleistocene last glacial sand sample. This ratio is similar, within 1? to the average ratio of the modern sand indicating similar exposure-burial histories during transport in spite of the difference in climatic conditions. The results imply a steady, pre-burial cosmogenic nuclide ratio related to the Nile River's ability, through storage and recycling, to buffer the effects of climatic and tectonic perturbations on cosmogenic nuclide concentrations in the transported quartz. All ancient and buried sand samples (n=9) fall on a decay path which originates from concentrations and ratio of 26Al and 10Be in modern sand suggesting steady pre-burial concentrations of cosmogenic nuclides in quartz sand over the past 2.5 Ma.

Matmon, Ari; Davis, Michael; Rood, Dylan; Avnaim-katav, Simona

2013-04-01

363

Simulation of the electrification of wind-blown sand.  

PubMed

The triboelectric charging of collision particles is essential to understand sand electrification in wind-blown sand fluxes. The physical model of electron trapped in high-energy states has been proposed to explain the triboelectric charging between identical insulating granular materials. In this study we propose an improved triboelectric charging model which combines the soft sphere model and the trapped electron model to calculate the net charge transfer during particles' collisions. Based on our charging model, we investigate the sand electrification of wind-blown sand, such as the charge flux varying with height, the charge-to-mass ratio of wind-blown sand, and the equilibrium time that the charge takes to approach a stable state. Numerical simulation results of the averaged charge-to-mass ratio in wind-blown sand fluxes are in good agreement with the experimental data. PMID:22438041

Hu, Wenwen; Xie, Li; Zheng, Xiaojing

2012-03-23

364

Oil shale, tar sands, and related materials  

SciTech Connect

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

Stauffer, H.C.

1981-01-01

365

Robotics Strategy White Paper.  

National Technical Information Service (NTIS)

The enclosed Robotics Strategy White Paper is the result of a collaborative effort between the U.S. Army Training and Doctrine Command (TRADOC) and the Tank-Automotive Research, Development and Engineering Center (TARDEC). This paper builds on a confedera...

2009-01-01

366

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

367

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

368

Heating tar sands formations while controlling pressure  

DOEpatents

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

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

2010-01-12

369

X-ray Analysis of Sand  

NSDL National Science Digital Library

This is an x-ray diffraction analysis of six sand samples and comparison with hand specimens. Students look at each of the six samples under the binocular microscope and note such useful properties as number of minerals, cleavage/fracture, color, shape, grain size, roundness, and degree of sorting. Then they grind up small amounts of each sample and mount them on glass slides for X-ray. Students write all sample descriptions and X-ray analysis results in their lab notebook. Then they identify the minerals in each sample, determine where they are from, and write a report summarizing all results.

Perkins, Dexter

370

Biogenic crust dynamics on sand dunes  

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

371

Advances benefit tight gas sands development  

SciTech Connect

Advances in four key technologies have been important for more efficient development of tight gas sands. The advances are: (1) expanded use of 3D seismic; (2) integrated approaches to natural fracture detection; (3) improved well completions and advanced stimulation technology; and (4) selected use of horizontal wells. In addition, advances in drill bits, downhole motors, and basic procedures have significantly reduced the costs of producing tight gas, as demonstrated by an impressive increase in rate of penetration and associated reduction in costs for new wells. This paper reviews each of these areas of new or improved technology.

Kuuskraa, V.A.; Hoak, T.E.; Kuuskraa, J.A. [Advanced Resources International Inc., Arlington, VA (United States); Hansen, J. [Gas Research Inst., Chicago, IL (United States)

1996-04-08

372

Tour of Park Geology: Sand Dunes  

NSDL National Science Digital Library

This Park Geology site provides links to tours of individual National Parks, Monuments, and Recreation Areas with sand dunes. Where appropriate for each park, links are provided to maps, photographs, geologic research, related links, visitor information, and teacher features (resources for teaching geology with National Park examples). The list includes places such as Death Valley and Mojave National Preserve, along with less well-known areas such as the Pictured Rocks National Lakeshore in Michigan and the Wright Brothers National Memorial in North Carolina.

373

Relationships Between Sand and Water Quality at Recreational Beaches  

PubMed Central

Enterococci are used to assess the risk of negative human health impacts from recreational waters. Studies have shown sustained populations of enterococci within sediments of beaches but comprehensive surveys of multiple tidal zones on beaches in a regional area and their relationship to beach management decisions are limited. We sampled three tidal zones on eight South Florida beaches in Miami-Dade and Broward counties and found that enterococci were ubiquitous within South Florida beach sands although their levels varied greatly both among the beaches and between the supratidal, intertidal and subtidal zones. The supratidal sands consistently had significantly higher (p<0.003) levels of enterococci (average 40 CFU/g dry sand) than the other two zones. Levels of enterococci within the subtidal sand correlated with the average level of enterococci in the water (CFU/100mL) for the season during which samples were collected (rs= 0.73). The average sand enterococci content over all the zones on each beach correlated with the average water enterococci levels of the year prior to sand samplings (rs=0.64) as well as the average water enterococci levels for the month after sand samplings (rs=0.54). Results indicate a connection between levels of enterococci in beach water and sands throughout South Florida’s beaches and suggest that the sands are one of the predominant reservoirs of enterococci impacting beach water quality. As a result, beaches with lower levels of enterococci in the sand had fewer exceedences relative to beaches with higher levels of sand enterococci. More research should focus on evaluating beach sand quality as a means to predict and regulate marine recreational water quality.

Phillips, Matthew C.; Solo-Gabriele, Helena M.; Piggot, Alan M.; Klaus, James S.; Zhang, Yifan

2011-01-01

374

Role of sand capping in phosphorus release from sediment  

Microsoft Academic Search

Sand is the simplest capping material proposed to date to contain phosphorus in sediment in situ. This research was carried out to understand the role of sand capping in the speciation and release of phosphorus from sediment.\\u000a Clean sand was laid on sediment sampled at a eutrophicated lake in one dimensional columns with different capping thicknesses.\\u000a It could be understood

Geonha Kim; Woohyeuk Jung

2010-01-01

375

Technical Problems in the Mining of Tar Sands  

Microsoft Academic Search

Factors which affect the selection of equipment, mine layout, and sequence of operations are discussed as they relate to the open-pit mining of tar sands. These factors include the overburden to-tar-sand ratio, geological, and hydrological conditions and general limitations of open pit methods. Overburden removal is discussed from the standpoints of overburden properties, equipment selection, and field operations. Tar sand

KFM Gold

1967-01-01

376

Have the northwest Negev dunefield sands reddened since their deposition?  

Microsoft Academic Search

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

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

2010-01-01

377

Final report on Thermally Modified Sand demonstration project  

SciTech Connect

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

Not Available

1994-09-23

378

Modelling sand–mud morphodynamics in the Friesche Zeegat  

Microsoft Academic Search

The objective of the study presented in this paper is to investigate the predictive capabilities of a process-based sand–mud model in a quantitative way. This recently developed sand–mud model bridges the gap between noncohesive sand models and cohesive mud models. It explicitly takes into account the interaction between these two sediment fractions and temporal and spatial bed composition changes in

Mathijs van Ledden; Zheng-Bing Wang; Han Winterwerp; Huib de Vriend

2006-01-01

379

The morphodynamic modelling of tidal sand waves on the shoreface  

Microsoft Academic Search

An artificial sand wave on the Dutch shoreface of the North Sea has been studied in conditions with relatively strong tidal currents in the range of 0.5 to 1 m\\/s and sediments in the medium sand size range of 0.2 to 0.5 mm. The sand wave is perpendicular to the tidal current and has a maximum height and length of the order

P. K. Tonnon; L. C. van Rijn; D. J. R. Walstra

2007-01-01

380

Why Count Types of White Blood Cells?  

NSDL National Science Digital Library

How can we make use of complex cellular level responses in the human body to microbial infections and other disorders? Why is it important to differentiate between white blood cells in a blood sample and keep a record of their numbers? Improve skills at cell identification and explore these questions with the program Cell Differentials. * identify lymphocytes in a clinical laboratory simulation of blood cell counts

Ethel D. Stanley (Beloit College;Biology); Donald Buckley (Quinnipiac University;Biology)

2006-05-20

381

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

PubMed

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

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

2011-09-28

382

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

383

White Students Reflecting on Whiteness: Understanding Emotional Responses.  

PubMed

In the present investigation, the authors explored potential predictors of White students' general emotional responses after they reflected on their Whiteness in a semi-structured interview (n = 88) or written reflection (n = 187). Specifically, the authors examined how color-blindness (i.e., awareness of White privilege) and racial affect (i.e., White empathy, White guilt, and White fear), assessed before the interview or written reflection, may predict positive and negative emotional responses, assessed immediately following the interview or written reflection. Furthermore, the authors considered whether affective costs of racism to Whites moderated the association between racial color-blindness and general positive and negative emotional responses of White students. Findings indicated that affective costs of racism moderated associations between racial color-blindness and general emotional responses. Specifically, White fear moderated associations for the written reflection group whereas White empathy moderated an association in the interview. White guilt did not moderate, but instead directly predicted a negative emotional response in the written reflection group. Findings suggest that the interaction between racial color-blindness and racial affect is important when predicting students' emotional responses to reflecting on their Whiteness. Implications for educators and administrators are discussed. PMID:20657811

Todd, Nathan R; Spanierman, Lisa B; Aber, Mark S

2010-06-01

384

Hand transmitted vibrations caused by orbital hand sanding machines.  

PubMed

The paper reports and analyses results of vibration measurement carried out on orbital hand sanding machines. Vibrations were measured on the front and rear handles of the FESTO LRB-W1 and LRB-T1 orbital hand sanding machines and at two points on the holding handle of the FESTO RTL-F1 hand sanding machine. The measured levels of the weighted vibration accelerations were compared to the daily exposure limits according to ISO 5349, ISO/TC 108/SC4/14 and NF E90-402. Daily exposures for each type of sanding machine were determined according to the same standards. PMID:7575142

Goglia, V; Risovi?, S; Beljo, R

1995-03-01

385

Perceived Whiteness under Different Lighting Conditions  

NASA Astrophysics Data System (ADS)

Many white and nearly white objects are in our living and working areas, such as documents written on white paper, white curtains, white clothes, white walls, and white furniture. The perceived whiteness of these objects is important to the impression of the lighting in these areas. To investigate the perceived whiteness in living areas, a series of experiments were conducted using four different fluorescent lamps in three different environments. It was found that the areas of perceived whiteness in the living area environments were larger than the areas of perceived whiteness under achromatic conditions. Based on these results, a perceived whiteness index is proposed for these experimental conditions.

Oota, Akiko; Kanaya, Sueko; Ayama, Miyoshi; Mukai, Kenji

386

An airborne assessment of atmospheric particulate emissions from the processing of Athabasca oil sands  

NASA Astrophysics Data System (ADS)

During the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign, two NASA research aircraft, a DC-8 and a P-3B, were outfitted with extensive trace gas (the DC-8) and aerosol (both aircraft) instrumentation. Each aircraft spent about a half hour sampling air around the oil sands mining and upgrading facilities near Ft. McMurray, Alberta, Canada. The DC-8 circled the area, while the P-3B flew directly over the upgrading plants, sampling close to the exhaust stacks, then headed downwind to monitor the aerosol as it aged. At short range, the plume from the oil sands is a complex mosaic of freshly nucleated ultrafine particles from a SO2 and NO2-rich plume, fly ash and soot from industrial processes, and dust from dirt roads and mining operations. Shortly downwind, organic aerosol appears in quantities that rival SO4=, either as volatile organic vapors condense or as they react with the H2SO4. The DC-8 pattern allowed us to integrate total flux from the oil sands facilities within about a factor of two uncertainty that spanned values consistent with 2008 estimates from reported SO2 and NO2 emissions. In contrast, CO fluxes exceeded reported regional emissions, due either to variability in production or sources missing from the emissions inventory. The conversion rate of SO2 to aerosol SO4= of ~6% per hour is consistent with earlier reports, though OH concentrations are insufficient to accomplish this. Other oxidation pathways must be active. Altogether, organic aerosol and black carbon emissions from the oil sands operations are small compared with the forest fires present in the region during the summer. The oil sands do contribute significant sulfate and exceed fire production of SO2 by an order of magnitude.

Howell, S. G.; Clarke, A. D.; Freitag, S.; McNaughton, C. S.; Kapustin, V.; Brekovskikh, V.; Jimenez, J.-L.; Cubison, M. J.

2013-08-01

387

Diversity of phlebotomine sand flies (Diptera: Psychodidae) in Ibitipoca State Park, Minas Gerais, Brazil.  

PubMed

Leishmaniasis is a complex of zoonotic diseases that are endemic to many Brazilian states. They are transmitted to the vertebrates by the bite of the hematophagous female sand fly (Diptera: Psychodidae) vectors. Despite the increasing occurrence of visceral and cutaneous leishmaniasis cases in large urban centers, their transmission continues to occur primarily in a wild environment and may be associated with professional activities, ecotourism activities, or both. This study investigates the ecological parameters of the sand flies present in Ibitipoca State Park, Minas Gerais, Brazil. During 2009, systematic collections of sand flies were made monthly using HP light traps installed at five sites, including three natural settings (a cave, riparian vegetation, and a rain forest), the tourist and researchers' accommodations, and a surrounding domestic livestock area. In total, 161 sand flies (seven species) were collected, the most abundant, particularly in the surrounding domestic livestock area, being Lutzomyia (Psychodopygus) lloydi (Antunes, 1937). Furthermore, a previously unidentified Lutzomyia (Sciopemyia) sp. was prevalent in the cave environment. There are no existing records of the occurrence of leishmaniasis in Ibitipoca State Park; however, the some species of the subgenus Psychodopygus are known vectors of Leishmania spp in Brazil. Hence, the presence of a species of this genus in areas surrounding the park may represent a risk to ecotourism and the local inhabitants. Our study shows the importance of regular monitoring of the various areas used by humans to determine the distribution and spread of sand fly vectors for preventive management to forestall potential risk to health and consequent effect on ecotourists. PMID:21845934

Carvalho, Gustavo Mayr de Lima; De Vasconcelos, Fernanda Bernardes; Da Silva, Daniela Gonçalves; Botelho, Helbert Antônio; Filho, José Dilermando Andrade

2011-07-01

388

Kootenai River white sturgeon studies.  

National Technical Information Service (NTIS)

This report evaluates natural spawning of white sturgeon in the Kootenai River before, during, and after the 1993 augmented discharge period. To determine how altering the operation of Libby Dam may improve conditions for natural spawning of white sturgeo...

P. J. Anders

1993-01-01

389

Storms, shoreface morphodynamics, sand supply, and the accretion and erosion of coastal dune barriers in the southern North Sea  

NASA Astrophysics Data System (ADS)

The coast of the southern North Sea is bound by dune barriers that have developed adjacent to a shallow storm- and tide-dominated shoreface comprising numerous shore-parallel to sub-shore-parallel tidal sand banks. The banks evolve under the joint control of tide-, wave- and wind-induced shore-parallel currents, which tend to 'stretch' them, eventually leading to bank division, and to shoaling and breaking storm waves, which tend to drive them ashore. The banks, thus, modulate the delivery of storm wave energy to the coast, redirect currents alongshore and are the sand sources for the accretion of coastal dunes. Foredune accretion occurs where major sand banks have migrated shoreward over the last centuries to be finally driven ashore and weld under the impact of storm waves. Morphological changes in the bank field can impact on shoreline stability through dissipation or enhanced shoreward transmission of storm wave energy and effects on radiation stress, particularly when waves are breaking over the banks. Where banks are close to the shore, mitigation of offshore sediment transport, especially during storms, can occur because of gradients in radiation stress generated by the complex 3D bank structure. These macro-scale mechanisms involve embedded meso-scale interactions that revolve around the mobility of sand waves, mobility of beach bars and troughs and foredune mobility, and micro-scale processes of bedform mobility in the subaqueous and intertidal domains, and of swash and aeolian beach–dune sand transport. These embedded interactions and the morphodynamic feedback loops illustrate the importance of synchroneity of sand transport from shoreface to dune on this coast.Large stretches of the foredunes show either signs of stability, or mild but chronic erosion. Furthermore, a demonstrated lack of a clear relationship occurs between storminess and coastal response over the second half of the 20th century. The present situation may be indicative of conditions of rather limited sand supply from offshore, notwithstanding the abundance of sand on the nearby shallow shoreface, except in areas where a nearshore storm-driven tidal sand bank has become shore-attached. Apart from the important influence of shoreface sand banks and of wave–bank interactions, foredune accretion and erosion also depend on various context controls that include individual storm characteristics, wind speed and incidence relative to the shore, tidal stage during storms, and direct human intervention on the shore through foredune and beach management. The bewildering variability inherent in these intricately related parameters may also explain the poor relationship between storminess and barrier shoreline change and will still continue to render unpredictable the response of shores to individual storms.

Anthony, Edward J.

2013-10-01

390

Three-link Swimming in Sand  

NASA Astrophysics Data System (ADS)

Many animals move within in granular media such as desert sand. Recent biological experiments have revealed that the sandfish lizard uses an undulatory gait to swim within sand. Models reveal that swimming occurs in a frictional fluid in which inertial effects are small and kinematics dominate. To understand the fundamental mechanics of swimming in granular media (GM), we examine a model system that has been well-studied in Newtonian fluids: the three-link swimmer. We create a physical model driven by two servo-motors, and a discrete element simulation of the swimmer. To predict optimal gaits we use a recent geometric mechanics theory combined with empirically determined resistive force laws for GM. We develop a kinematic relationship between the swimmer's shape and position velocities and construct connection vector field and constraint curvature function visualizations of the system dynamics. From these we predict optimal gaits for forward, lateral and rotational motion. Experiment and simulation are in accord with the theoretical predictions; thus geometric tools can be used to study locomotion in GM.

Hatton, R. L.; Ding, Yang; Masse, Andrew; Choset, Howie; Goldman, Daniel

2011-11-01

391

TESTING OF TMR SAND MANTIS FINAL REPORT  

SciTech Connect

Screening tests of Sand Mantis candidate materials selected for erosion resistance have been completed. The results of this testing identified that over a relatively short period of operation (<1 hour), measurable erosion will occur in each of the candidate zoom tube materials given equal operating exposure. Additionally, this testing has shown that erosion of the rubber discharge hose directly downstream of the vehicle could be expected to limit the service life of the discharge hose. On the basis of these test results, SRNL recommends the following; {lg_bullet} redesign of critical system components (e.g., zoom tube, discharge hose) should be conducted to improve system characteristics relative to erosion and capitalize on the results of this testing, {lg_bullet} continued efforts to deploy the Sand Mantis should include testing to better define and optimize operating parameters, and gain an understanding of system dynamics, {lg_bullet} discontinue wear testing with the selected materials pending redesign of critical system components (1st recommendation) and inclusion of other candidate materials. The final selection of additional candidate materials should be made following design changes, but might include a Stellite alloy or zirconia.

Krementz, D; William Daugherty, W

2007-06-12

392

High natural radiation in Brazilian sands  

NASA Astrophysics Data System (ADS)

The present work investigated Brazilian beach sands in order to analyze the total external natural radiation dose using a gamma-ray spectrometry technique. The activities from the radionuclides 40K and the elements from the series of 238U and 232Th were measured. The sand samples from Morro Branco beach, Ceará, and Itacaré beach, Bahia, presented different colors and grain size than the beaches from Sa~o Paulo. A sample collected in Itacaré beach showed an effective dose of 2.5 (1) mSv/yr. This value is outside the annual typical range (0.3-0.6 mSv) indicated by the United Nations Scientific Committee on the Effects of Atomic Radiation. The high effective dose found in Itacaré beach is mainly due to the presence of a large amount of 232Th and 238U. All the other samples collected in Ceará and Sa~o Paulo States are inside the annual typical range. Energy-Dispersive X-Ray Spectroscopy (EDS) microanalysis showed that this high external radiation is related to the presence of zircon and monazite, which commonly carry traces of uranium and thorium.

Silveira, M. A. G.; Medina, N. H.; Pereira, B. R.; Aguiar, V. A. P.

2012-02-01

393

Aeolian sand transport: Experiment and Theory  

NASA Astrophysics Data System (ADS)

Experiments on aeolian sand transport were carried out in a wind tunnel at the University of Aarhus in Denmark for a wide range of wind speeds. The saltating particles were analyzed using imaging techniques (PIV and PTV). Vertical profiles of particle concentration and velocity were extracted. The particle concentration was found to decrease exponentially with the height above the bed and the characteristic decay height was independent of the wind speed (Creyssels et al., 2009). In contrast with the logarithmic profile of the wind speed, the particle velocity was found to vary linearly with the height. In addition, the particle slip velocity is finite and invariant with the wind speed. These results are shown to be closely related to the features of the splash function that characterizes the impact of the saltating particles onto a sand bed. A numerical simulation was developed that explicitly incorporates low velocity moments of the splash function in a calculation of the boundary conditions that apply at the bed (Creyssels et al., 2009). The overall features of the experimental measurements are well reproduced by the simulation. Reference: M. Creyssels, P. Dupont, A. Ould el Moctar, A. Valance, I. Cantat, J. T. Jenkins, J. M. Pasini and K. R. Rasmussen, J. Fluid Mech. 625, 47 (2009).

Valance, A.; Ould Eld Moctar, A.; Dupont, P.; Cantat, I.; Jenkins, J.

2010-05-01

394

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

Microsoft Academic Search

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

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

2010-01-01

395

Variation of Skin Damage with Flow Rate Associated with Sand Flow or Stability in Unconsolidated-Sand Reservoirs  

Microsoft Academic Search

A semi-cylindrical sand-pack model of a cased-and-perforated completion was loaded with an overburden pressure and fluid flowed through the pack to simulate production. Flow rate was gradually increased in each test. Sand arches formed to stabilize sand movement. As reported previously by the same authors, arch size was a function of flow rate. Skin effect caused by arch formation, destruction,

D. B. Tippie; C. A. Kohlhaas

1974-01-01

396

Humic substances increase the effectiveness of iron sulfate and Vivianite preventing iron chlorosis in white lupin  

Microsoft Academic Search

The main objective of this work was to study the influence of humic substances (HS) on the effectiveness of Fe sulfate and\\u000a Vivianite in preventing Fe chlorosis in white lupin with a view of performing cost-effective methods to overcome the problem.\\u000a Two consecutive crops were performed using calcareous sand treated with different Fe sources (FeSO4·7H2O and Vivianite, at three different

Ana de Santiago; José M. Quintero; Eusebio Carmona; Antonio Delgado

2008-01-01

397

Solidification of high-Cr white cast iron–WC particle reinforced composites  

Microsoft Academic Search

A double casting technique using sand casting that has been developed to produce a high-Cr white cast iron (WCI) based material having an in situ and ex situ carbide particle reinforced wear resistant composite region that extends to a depth of 5–8mm below the working surface is described. The WC particles were directed to a specific location in the ingot

K. Kambakas; P. Tsakiropoulos

2005-01-01

398

Characterization and corrosion behavior of high-chromium white cast irons  

Microsoft Academic Search

Erosion-resistant high-chromium white cast irons (CWIs) are widely used in hydrotransport components, particularly in oil-sand\\u000a operations. Due to the acceptance that corrosion processes can accentuate material degradation by erosion processes andvice versa, it is important to understand the corrosion resistance of these materials in the environments in which they are used. Three\\u000a CWI alloys with different chemical compositions—chromium (26 to

A. Neville; F. Reza; S. Chiovelli; T. Revega

2006-01-01

399

Use of quarry dust instead of river sand for future constructions in Sri Lanka  

Microsoft Academic Search

The construction industry of Sri Lanka expects a serious shortage of sand in the near future due to over exploitation of river sand. Then, the entire construction industry will be paralyzed if there are no alternative sources instead of river sand. Near-shore marine sand, dune sand and quarry dust (crushed rocks) are the other alternative sources available for it in

S. JAYAWARDENA

400

A wind tunnel experiment of sand transport and its comparison with the Werner model  

Microsoft Academic Search

We carried out a wind tunnel experiment on aeolian transport of sand. Fluorescence-dyed grains of sand were embedded in the sand bed in a wind tunnel, and their dispersion was recorded by a video camera. Dispersion of colored sand both downwind and in the crosswind direction are examined. The concentration of colored sand decreases as an exponential function of the

Y. Hatano; Y. Kanda; K. Udo; S. Takewaka; R. Ueki; N. Hatano; H. Mouri; M. Chiba; K. Kurihara; H. Nishimura

2004-01-01

401

Sand encroachment by wind in Al-Hasa of Saudi Arabia  

Microsoft Academic Search

Sand drift and sand dune movement rates in the study area are controlled by several major factors. These factors in descending order of importance are: wind characteristics (velocity, duration, and direction), mean sand grain size, dune size, sand volume available for transport, moisture content of the sand and density of vegetal cover. The objective of this study was to determine

Y. M. S. Abolkhair

1981-01-01

402

Egg White Phantoms for HIFU  

SciTech Connect

We used fresh egg white and polyacrylamide to create a transparent tissue mimicking phantom. Heating of phantoms by HIFU leads to egg white protein denaturation and creation of visible white lesions. We measured the acoustical and thermal properties and investigated the possibility to use such phantoms to study the lesion formation during the HIFU therapy.

Divkovic, Gabriela; Jenne, Juergen W. [German Cancer Research Center Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

2005-03-28

403

Endorsing Obama licenses favoring Whites  

Microsoft Academic Search

Three studies tested whether the opportunity to endorse Barack Obama made individuals subsequently more likely to favor Whites over Blacks. In Study 1, participants were more willing to describe a job as better suited for Whites than for Blacks after expressing support for Obama. Study 2 replicated this effect and ruled out alternative explanations: participants favored Whites for the job

Daniel A. Effron; Jessica S. Cameron; Benoît Monin

2009-01-01

404

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

PubMed Central

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

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

2009-01-01

405

The effect of methane hydrate morphology and water saturation on seismic wave attenuation in sand under shallow sub-seafloor conditions  

NASA Astrophysics Data System (ADS)

A better understanding of seismic wave attenuation in hydrate-bearing sediments is needed for the improved geophysical quantification of seafloor methane hydrates, important for climate change, geohazard and economic resource assessment. Hence, we conducted a series of small strain (<10-6), seismic frequency (50-550 Hz), laboratory resonant column experiments on synthetic methane hydrate-bearing sands under excess-water seafloor conditions. The results show a complex dependence of P- and S-wave attenuation on hydrate saturation and morphology. P- and S-wave attenuation in excess-water hydrate-bearing sand is much higher than in excess-gas hydrate-bearing sand and increases with hydrate saturation between 0 and 0.44 (the experimental range). Theoretical modelling suggests that load-bearing hydrate is an important cause of heightened attenuation for both P- and S-waves in gas and water saturated sands, while pore-filling hydrate also contributes significantly to P-wave attenuation in water saturated sands. A squirt flow attenuation mechanism, related to microporous hydrate and low aspect ratio pores at the interface between sand grains and hydrate, is thought to be responsible for the heightened levels of attenuation in hydrate-bearing sands at low hydrate saturations (<0.44).

Best, Angus I.; Priest, Jeffrey A.; Clayton, Christopher R. I.; Rees, Emily V. L.

2013-04-01

406

Contact with beach sand among beachgoers and risk of illness.  

PubMed

Recent studies of beach sand fecal contamination have triggered interest among scientists and in the media. Although evidence shows that beach sand can harbor high concentrations of fecal indicator organisms, as well as fecal pathogens, illness risk associated with beach sand contact is not well understood. Beach visitors at 7 US beaches were enrolled in the National Epidemiological and Environmental Assessment of Recreational Water (NEEAR) Study during 2003-2005 and 2007 and asked about sand contact on the day of their visit to the beach (digging in the sand, body buried in the sand). Then, 10-12 days after their visit, participants were telephoned to answer questions about any health symptoms experienced since the visit. The authors completed 27,365 interviews. Digging in the sand was positively associated with gastrointestinal illness (adjusted incidence proportion ratio (aIPR) = 1.13, 95% confidence interval (CI): 1.02, 1.25) and diarrhea (aIPR = 1.20, 95% CI: 1.05, 1.36). The association was stronger between those buried in the sand and gastrointestinal illness (aIPR = 1.23, 95% CI: 1.05, 1.43) and diarrhea (aIPR = 1.24, 95% CI: 1.01, 1.52). Nonenteric illnesses did not show a consistent association with sand contact activities. Sand contact activities were associated with enteric illness at beach sites. Variation in beach-specific results suggests that site-specific factors may be important in the risk of illness following sand exposure. PMID:19541858

Heaney, Christopher D; Sams, Elizabeth; Wing, Steve; Marshall, Steve; Brenner, Kristen; Dufour, Alfred P; Wade, Timothy J

2009-06-18

407

White polarization sandwiches: optical elements with non-orthogonal eigenpolarizations  

NASA Astrophysics Data System (ADS)

Optical elements with non-orthogonal eigenpolarizations have complex anisotropic properties, which are not yet well understood. As an example of such elements, we studied theoretically the class of white polarization sandwiches. Light passing successively through two identical white sandwiches preserves its polarization state, so that, following the terminology of Berry and Dennis, white polarization sandwiches can be regarded as non-trivial square roots of unity. This paper presents a general Jones matrix of white polarization sandwiches and discusses its spectral properties. It further discusses a way to synthesize white sandwiches. Our analysis shows that a general white polarization sandwich has complex anisotropic properties comprising all four basic anisotropy mechanisms: linear and circular dichroism and linear and circular birefringence. Several simple examples of synthesized white sandwiches show, however, that the form, orientation and rotation direction of their eigenpolarization ellipses can be easily controlled by changing a single parameter of the constituent elements. The results could contribute to understanding the properties of optical elements with non-orthogonal eigenpolarizations and, more generally, elements with anisotropic absorption.

Sydoruk, O.; Savenkov, S. N.

2010-03-01

408

Fluid Flow and Solute Transport in the Bullwinkle Field J2 Sand, Offshore Gulf of Mexico  

NASA Astrophysics Data System (ADS)

The Bullwinkle field is located in a Pliocene-Pleistocene salt withdrawal minibasin approximately 90 km southwest of New Orleans, Louisiana. Most of the production has been from the prolific "J" sand sequence, a late Pliocene age channel and sheet sand turbidite complex. Salinities of the oil-leg waters (i.e., the pre-production immobile waters located above the original oil-water contact) vary from over 300 g/L near salt to approximately 150 g/L at the original oil-water contact in the J2 sand. Aquifer waters below the original oil-water contact generally have salinities between 150 g/L and 100 g/L. We developed numerical models to simulate fluid flow and associated solute transport in a gently dipping, relatively thin but high permeability sand body such as the J2 sand in Bullwinkle field. Dissolution of salt exposed in the updip portion of a confined aquifer can generate kilometer-scale fluid circulation with velocities of 10-40 cm/yr. Aquifer dips can be less than 5 degrees. Salt dissolution can generate a dense brine throughout a minibasin scale aquifer within 10,000 to 100,000 years. The fluid circulation pattern and amount of salt dissolved depends on permeability, dip, dispersivity, salt available for dissolution, and aquifer thickness. Dissolution of salt is massive, 1 billion kg or more. Salt dissolution within aquifers may be an important process in removing the last few meters of salt to form salt welds. Stratigraphic variations in aquifer salinity may be related to differences in spatial/temporal contact with salt bodies rather than a complex pattern of fluid migration. Once salt dissolution stops, continued density driven flow in minibasin scale aquifers will largely eliminate spatial variations in salinity. Introduction of hydrocarbons must be rapid in order to preserve the observed spatial gradients in oil-leg water salinity. Model simulations indicate that vertical as well as horizontal spatial variations in preproduction oil-leg water salinities may exist. Pre- production spatial distributions of oil-leg and aquifer waters salinities in the J sands of the Bullwinkle field are quantitatively consistent with: fluid circulation driven by updip dissolution of salt; introduction of hydrocarbons which traps oil-leg waters and stops further salt dissolution; and continued mixing of aquifer waters driven by density driven flow until salinity variations are largely eliminated.

Nunn, J. A.; Hanor, J. S.

2006-12-01

409

On the Relationship Between Microstructure and Electrical and Hydraulic Properties of Sand-Clay Mixtures  

SciTech Connect

A series of laboratory experiments were performed on saturated sand-clay mixtures, including electrical properties, permeability and porosity. Different mixtures and configurations of quartz sand and 0 to 10% Na-montmorillonite clay saturated with solutions of CaCl{sub 2} and deionized water were investigated. The electrical properties were dependent on clay content, fluid conductivity, and microstructure in a complex fashion. Two main regions of conduction exist: a region dominated by surface conduction and a region where the ionic strength of the saturating fluid controlled conduction. For low fluid conductivities, the sample geometry was found to greatly affect the magnitude of the surface conductance. The influence of the microstructural properties on the electrical properties was quantified by estimating formation factors, {Lambda}-parameters, and surface conductances. We suggest that high and low bounds on the expected surface and bulk conductance of natural systems can be derived from the measurements on these artificial configurations.

Wildenschild, D.; Roberts, J.J.; Carlsberg, E.D.

1999-10-25

410

Imaging white light VISAR  

SciTech Connect

An imaging white light velocimeter consisting of two imagine superimposing Michelson interferometers in series with the target interposed is demonstrated. Interferometrically measured 2-D velocity maps can be made of moving surfaces using unlimited bandwidth incoherent and extended area sources. Short pulse and broadband chirped pulse lasers can be used to provide temporal resolution not possible with monochromatic illumination. A 20 m/s per fringe imaging velociemter is demonstrated using an ordinary camera flash for illumination.

Erskine, D.J.; Holmes, N.C.

1996-10-01

411

The White Oaks Laccoliths  

Microsoft Academic Search

IntroductionAbout 12 miles to the northeast of Carrizozo lies the ghost town of White Oaks. Thisonce thriving mining community rests in a small valley surrounded by three wrinkled androunded mountain peaks: the remains of a ancient cluster of laccoliths (see attachedFigure 1). To the northwest lies Lone Mountain with its associated peak, BaxterMountain, while to the southeast lies Patos Mountain

James Richardson

412

White coat principles.  

PubMed

The White Coat Ceremony, which many dental schools use to mark the transition to patient care, is an opportunity to reflect on the values of dental practice. Eight principles are offered for consideration: 1 ) patient care is the point of practice; 2) the doctor-patient relationship is essential; 3) discuss options and possibilities; 4) mistakes will be made; 5) tell the truth; be assertive; 7 ) consult; and 8) manage your stress and your life. PMID:15948496

Peltier, Bruce N

2004-01-01

413

White leafy seadragon  

NSDL National Science Digital Library

This seadragon is white with a light pattern. It has a snout (right end) and the back end is to the left. Seadragons can't hold onto sea plants like seahorses can. It has some fins along its back that it uses to propel itself and move around in the water. The leafy parts are only used to blend in and look like seaweed.

Wendy Rathey (None;)

2006-01-01

414

Sand Tray and Group Therapy: Helping Parents Cope  

Microsoft Academic Search

Sand tray with group therapy can be an effective treatment approach for parents coping with adolescent substance abuse and\\/or dependency. Excerpts of parent sand trays are presented to demonstrate pretreatment tasks that decrease denial, reduce reactive anger, stop enabling behaviors, and build support systems. Parent-child relational issues, including developmental delays, painful feelings, and substance abuse, are examined through the parents'

Linda James; Don Martin

2002-01-01

415

Analysis of open hole logs in the Miocene Stevens Sands  

Microsoft Academic Search

The analysis of open-hole logs in the Stevens Sands is difficult because of the mineralogical composition of the sands and the corresponding effects on the logging tools. Logging parameters presumed in other sandstone reservoirs may not be appropriate to the Stevens and may cause the log analysis to underestimate productive zones. Without the integration of full core data and knowledge

1991-01-01

416

12. INTERIOR VIEW WITH JAMES WILLIAMS REACHING FOR THE SAND ...  

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

12. INTERIOR VIEW WITH JAMES WILLIAMS REACHING FOR THE SAND RELEASE LEVER WHICH WILL OPEN THE OVERHEAD STORAGE BIN AND PERMIT A SET AMOUNT OF SAND TO BE DEPOSITED INTO THE FLASK PRIOR TO COMPRESSION BY THE MOLDING MACHINE INSIDE GREY IRON UNIT NO. 1. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

417

Bonding Strength by Methane Hydrate Formed among Sand Particles  

Microsoft Academic Search

The mechanical properties of methane hydrate-bearing sand were investigated by low temperature and high confining pressure triaxial testing apparatus in the present study. The specimens were prepared by infiltrating the methane gas into partially saturated sand specimen under the given temperature and stress condition which is compatible with the phase equilibrium condition for the stability of methane hydrate. The tests

M. Hyodo; Y. Nakata; N. Yoshimoto; R. Orense; J. Yoneda

2009-01-01

418

Cotton seedling abrasion and recovery from wind blown sand  

Technology Transfer Automated Retrieval System (TEKTRAN)

Millions of hectares of crops are exposed to wind blown sand abrasion each year and in many instances the damage is thought to be severe enough to require replanting. The goal of this study was to determine the effects of wind blown sand abrasion duration on cotton (Gossypium hirsutum L.) seedlings...

419

Effect of Sand in Growing Media on Selected Plant Species  

Microsoft Academic Search

Minimal use of relatively expensive imported inorganic and organic materials to be utilized for growing media such as peat moss is necessary for more profitable production in protected agriculture. The utilization of sand as an ingredient in a mixture in growing media s however limited in Kuwait, despite the fact that sand is ubiquitous, inexpensive to harvest and sustainable. The

H. Abo-Rezq; M. Albaho; B. Thomas

420

Taphonomic comparison between Recent and fossil sand dollars  

Microsoft Academic Search

The taphonomy of a Recent and a fossil sand dollar are compared. The recent Echinodiscus auritus originates from a shallow-water carbonate environment in the Red Sea. The fossil Parascutella höbarthi is found in micaceous sands of the Lower Miocene Austrian Molasse Zone. Both species show strong similarities in constructional morphology including the flattened overall shape, details of the surface morphology

James Nebelsick

1999-01-01

421

An outbreak of sand impaction in postpartum dairy cows  

PubMed Central

Twenty-two cases of indigestion occurred in a 650-cow herd. Five cows had severe sand abomasal impaction, diagnosed by laparotomy. The pH of prepartum cows’ urine was < 6.0 and of sand 8.0. Feed showed a dietary cation-anion difference ? ?110 mEq/kg. After feeding management corrections, no more cases were diagnosed.

Melendez, Pedro; Krueger, Traci; Benzaquen, Mauricio; Risco, Carlos

2007-01-01

422

Sand dune mobilization caused by regional warming in Otintag, China  

Microsoft Academic Search

Remobilization of fixed or semi-fixed sand dunes is the main process of desertification, which is sensitive to climate change. We analyzed 35-year temperature and precipitation data at three meteorological stations in Otintag Sandy Land, and calculated sand dune mobility index by employing the method suggested by Lancaster. In the last 35 years, the regional temperature tended to increase, whereas precipitation,

Baolin Zhang; Xiaoju Lu; Ruilin Luo

2010-01-01

423

Beach Sand Analysis for Indicators of Microbial Contamination  

EPA Science Inventory

Traditional beach monitoring has focused on water quality, with little attention paid to health risks associated with beach sand. Recent research has reported that fecal indicator bacteria, as well as human pathogens can be found in beach sand and may constitute a risk to human h...

424

SLOW SAND FILTER MAINTENANCE COSTS AND EFFECTS ON WATER QUALITY  

EPA Science Inventory

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

425

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

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

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

426

Distribution of Sand Dune Successional Species in Monterey Bay  

Microsoft Academic Search

Malkinson et al. (2003) state that the spatial patterns on sand dunes of individual species changed from clustered to regular as succession progressed as the result of the change in relative importance of facilitation and competition. This theory was used to examine the distribution of sand dune succession species in Monterey Bay. We used a quadrat-based approach on randomly selected

David Priestley; Kate Raine; Charlotte Robinson

427

FY 80 Tar Sands Program first quarterly report, January 1980  

Microsoft Academic Search

Research and development efforts in support of the Tar Sands program well completions and stimulation subactivity and new and novel concepts task have been initiated. The objectives of the well completion and stimulation efforts are to carry out research and development in areas with significant for long-range tar sand extraction development as well as provide potential interaction and support of

R. L. Fox; J. R. Wayland

1980-01-01

428

Extraction of vanadium from athabasca tar sands fly ash  

Microsoft Academic Search

The production of refinery grade oil from the Alberta tar sands deposits as currently practiced by Suncor (formally Great Canadian Oil Sands Ltd.---GCOS) generates a substantial amount of petroleum coke fly ash which contains appreciable amounts of valuable metals such as vanadium, nickel and titanium. Although the recovery of vanadium from petroleum ash is a well established commercial practice, it

C. O. Gomez-Bueno; D. R. Spink; G. L. Rempel

1981-01-01

429

The extraction of bitumen from western tar sands. Annual report  

SciTech Connect

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

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

1990-07-01

430

The extraction of bitumen from western tar sands  

SciTech Connect

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

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

1990-07-01

431

Geostatistical Modeling of McMurray Oil Sands Deposits  

Microsoft Academic Search

The McMurray formation in the Athabasca oil sands deposits of Northern Alberta is part of the world's second largest proven crude oil reserves. The formation is characterized by stratigraphic layers that correspond to three different depositional environments: Marine, Estuarine and Fluvial facies. Resource estimation for oil sands has traditionally relied on polygonal and inverse distance schemes. These techniques are simple

Oy Leuangthong; Emmanuel Schnetzler; Clayton V. Deutsch

432

The AOSTRA role in developing energy from Alberta oil sands  

Microsoft Academic Search

The paper discusses the role of the crown corporation AOSTRA (Alberta Oil Sands Technology and Research Authority) in developing energy from the oil sands located in the northern section of Alberta. The objective of the Authority is to develop economically and environmentally acceptable technology through collaborative action by industry, university and government. This major objective is then subdivided into two

R. D. Humphreys

1979-01-01

433

Microclimate control upon sand microbiotic crusts, western Negev Desert, Israel  

Microsoft Academic Search

Approximately 20% of the world's arid zones are covered by eolian sand. Parts of the sand are occupied by microbiotic crusts or have the potential of sustaining microbiotic crusts, which may have a great impact upon geomorphological processes and the ecology of the ecosystem. Any attempt to understand the distribution of microbiotic crusts inevitably necessitates knowledge concerning the microclimate within

G. J Kidron; E Barzilay; E Sachs

2000-01-01

434

Documenting the global impacts of beach sand mining  

Microsoft Academic Search

For centuries, beach sand has been mined for use as aggregate in concrete, for heavy minerals, and for construction fill. The global extent and impact of this phenomenon has gone relatively unnoticed by academics, NGOs, and major news sources. Most reports of sand mining activities are found at the very local scale (if the mining is ever documented at all).

R. Young; A. Griffith

2009-01-01

435

Oil sands tailings sludge solidification and bitumen recovery  

Microsoft Academic Search

Canada is a forerunner in the development of oil sands mining and processing technology. At present two commercial plants, both of them surface mining operations are producing approximately 200,000 of syncrude per day. At both of these plants a hot water separation process is used.The vast amounts of tailings, consisting of bitumen, sand, fines and water, generated from the hot

B. D. Prasad Head

1988-01-01

436

Black, magnetic spherules from Pleistocene and recent beach sands  

Microsoft Academic Search

Magnetic spherules have been discovered in the natural concentrates of ilmenite and other heavy minerals that occur in beach sands of both Pleistocene and recent age. The spherules range in size from 80 to 650 . Those in any given deposit match the grain size of the matrix sand. The spherules consist mainly of magnetite (FeFe 2 O 4 ),

Marco T. Einaudi; Ursula B. Marvin

1967-01-01

437

Thermal reclaimer apparatus for a thermal sand reclamation system  

SciTech Connect

A thermal reclaimer apparatus is disclosed for thermally removing from the used foundry sand the organic matter that is present therein. The subject thermal reclaimer apparatus includes chamber means in which the used foundry sand is heated to a predetermined temperature for a preestablished period in order to accomplish the burning away of the organic matter that the used foundry sand contains. The chamber means includes inlet means provided at one end thereof and outlet means provided at the other end thereof. Feed means are cooperatively associated with the pipe means and thereby with the inlet means for feeding the used foundry sand through the inlet means into the chamber means. The subject thermal reclaimer apparatus further includes rotating means operative for effecting the rotation of the chamber means as the used foundry sand is being heated therein. The chamber means has cooperatively associated therewith burner means located at the same end thereof as the outlet means. The burner means is operative to effect the heating of the used foundry sand to the desired temperature within the chamber means. Tumbling means are provided inside the chamber means to ensure that the used foundry sand is constantly turned over, i.e., tumbled, and that the lumps therein are broken up as the chamber means rotates. Lastly, the used foundry sand from which the organic matter has been removed leaves the chamber means through the outlet means.

Deve, V.

1984-02-07

438

Which processes form the volcanic sands on Mars?  

Microsoft Academic Search

Volcanic sands are common at the surface of Mars. They are usually of basaltic composition. Occurrence of sands, mostly recognized as dark dune fields include numerous impact craters in the southern hemisphere [1], several volcanic provinces such as Cerberus and Syrtis Major[2], several impact craters in the northern hemisphere, the large basins (Hellas and Argyre), Valles Marineris, and the poles

M. Grégoire; D. Baratoux; N. Mangold; O. Arnalds; B. Platvoet; J. Bardinzeff; P. Pinet

2007-01-01

439

Wastewater Renovation in Buried and Recirculating Sand Filters  

Microsoft Academic Search

A replicated, multiyear field study was conducted to assess the re- duction of N, P and microbial indicators by a recirculating sand filter (RSF) and bu ried mu ltilayer sa nd filter patterned after the RU CK filter. The RSF's received 38 L m -~ d-1 of septic tank effluent, while the buried sand filters were loaded at 76 L

A. J. Gold; B. E. Lamb; G. W. Loomis; J. R. Boyd; V. J. Cabelli; C. G. McKiel

1992-01-01

440

Strength of sillimanite sand reinforced porcelain subjected to thermal shock  

Microsoft Academic Search

An attempt has been made to eliminate quartz and gradually replace felspar by sillimanite sand to improve the thermomechanical properties of porcelains. It has been observed that the quenching temperature difference (?T) required to initiate thermal stress fracture in the porcelain increased greatly, when compared to classical compositions, with gradual replacement of felspar by sillimanite sand. Similar behaviour has also

Soumen Maity; T. K. Mukhopadhyay; B. K. Sarkar

1997-01-01

441

Coupled analysis of sand stability in petroleum wellbores  

Microsoft Academic Search

There are several mechanisms that may be responsible for sand destabilization in petroleum wellbores, including strength decrease by capillarity and chemical reactions and the variation of pore pressure because of oil\\/water relative permeability changes. A micromechanical model that quantitatively captures the changes in capillary strength with water saturation in unconsolidated or weakly consolidated sand is proposed. The effect of chemical

Gang Han; Maurice B. Dusseault

2004-01-01

442

Wave-Propagation Studies in Laterally Confined Columns of Sand.  

National Technical Information Service (NTIS)

An experimental study of the relationship between pertinent wave-propagation parameters and the one-dimensional stress-strain behavior of two sands was conducted. The stress-strain relation for the sands was characterized by a nonlinear strain-hardening b...

W. J. Baker

1967-01-01

443

Western Tight Gas Sands Advanced Logging Workshop Proceedings.  

National Technical Information Service (NTIS)

An advanced logging research program is one major aspect of the Western Tight Sands Program. Purpose of this workshop is to help BETC define critical logging needs for tight gas sands and to allow free interchange of ideas on all aspects of the current lo...

J. B. Jennings H. B. Carroll

1982-01-01

444

Stress-strain transformations and liquefaction of sands  

Microsoft Academic Search

Presented in this paper are the results of the laboratory tests of sands performed for the purpose of defining the characteristics of the dynamic shear stress-shear strain relationships. For this purpose, the transformation of the initial stress-strain characteristics of undrained saturated sands was investigated separately. These transformations take place under conditions of an increase in pore pressure under the effect

Kosta V. Talaganov

1996-01-01

445

Modern sands of South America: composition, provenance and global significance  

Microsoft Academic Search

Standard petrographic methods were used to study 604 modern sands from South America, of which 351 came from rivers and 253 from beaches. In spite of the wide geomorphic contrasts, these sands belong to only three great families: (1) an immature Andean family of lithic arenites rich in volcanic and metamorphic grains that covers about 30% of South America; (2)

P. E. Potter

1994-01-01

446

Drained cavity expansion in sands exhibiting particle crushing  

NASA Astrophysics Data System (ADS)

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

Russell, A. R.; Khalili, N.

2002-04-01

447

FY 80 Tar Sands program. Second quarterly report, April 1980  

SciTech Connect

The research and development efforts in support of the Tar Sands program reservoir access and alternate extraction activities that were initiated last quarter have been continued and expanded. The development of a short course on the utilization of specialized drilling technology to Tar Sands has been investigated. The steam quality sampler is undergoing laboratory testing. Plans for a Tar Sands enhanced permeability workshop have been initiated. A special report on possible application of sand control methods to the Tar Sands steam injection test (TS-1S) experiment has been prepared. The first stage of the analysis of rf and microwave heating has been completed. The results of a series of laboratory experiments on in-situ hydrogenation are presented.

Wayland, J.R.; Fox, R.L.

1980-09-01

448

Heats of dissolution of tar sand bitumen in various solvents  

SciTech Connect

The dissolution of tar sand bitumen from a tar sand matrix was examined using three solvents: (1) dichloromethane, a polar-polarizable solvent; (2) toluene, a nonpolar-polarizable solvent; and (3) hexane, a nonpolar-nonpolarizable solvent. The dichloromethane had the highest dissolution energy, followed by toluene, with hexane having the lowest dissolution energy. These data were combined with heat of dissolution of recovered bitumen and heat of wetting of spent sand to calculate the bonding energy between bitumen and the mineral matrix. The interfacial bonding energy between tar sand bitumen and the mineral matrix was found to be in the region of 0 to 0.09 cal/g of bitumen, which is very small. This conclusion may find application in recovery of energy or bitumen from bitumen-wet tar sand deposits. 9 refs., 2 tabs.

Ensley, E.K.; Scott, M.

1988-05-01

449

Method and apparatus for hydrocarbon recovery from tar sands  

DOEpatents

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

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

1988-05-04

450

Method and apparatus for hydrocarbon recovery from tar sands  

SciTech Connect

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

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

1989-11-14

451

Scaling Laws in Aeolian Sand Transport  

NASA Astrophysics Data System (ADS)

We report on wind tunnel measurements on saltating particles in a turbulent boundary layer and provide evidence that over an erodible bed the particle velocity in the saltation layer and the saltation length are almost invariant with the wind strength, whereas over a nonerodible bed these quantities vary significantly with the air friction speed. It results that the particle transport rate over an erodible bed does not exhibit a cubic dependence with the air friction speed, as predicted by Bagnold, but a quadratic one. This contrasts with saltation over a nonerodible bed where the cubic Bagnold scaling holds. Our findings emphasize the crucial role of the boundary conditions at the bed and may have important practical consequences for aeolian sand transport in a natural environment.

Ho, T. D.; Valance, A.; Dupont, P.; Ould El Moctar, A.

2011-03-01

452

Direct Production of Silicones From Sand  

SciTech Connect

Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

2001-09-30

453

Great Sand Dunes National Monument and Preserve  

NSDL National Science Digital Library

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

454

Persistent sand bars explained by geodynamic effects  

NASA Astrophysics Data System (ADS)

The persistent nature of intertidal sand bars has been the subject of much speculation concerning the hydrodynamic mechanisms involved, but its origin remains enigmatic. Here, we introduce salient geophysics in contrast to the physics of fluids above the sediments. The geophysical evidence combined with theoretical modeling and analysis demonstrates that the geodynamic processes ensuing during exposure periods have a profound impact, yielding the persistent nature of the intertidal bars under severe hydrodynamic forcing which would otherwise lead to unstable bar behavior. The feedback between the effects of the dynamics of suction, i.e. negative pore water pressure relative to atmospheric air pressure, and sediment transport and morphology is found to play a crucial role in the intertidal bar morphodynamics. Our finding may fundamentally alter the current perspective, leading to a new level of understanding, of sediment transport and bar behavior at waterfronts that are ubiquitous in rivers, estuaries, and coastal seas.

Sassa, Shinji; Watabe, Yoichi

2009-01-01

455

The shifting sands of a professional identity.  

PubMed

I decided while an undergraduate that I wanted to be a psychologist. Beyond that, I'm still not sure what I'll do when I grow up. This brief autobiography maps the shifting sands of my professional identity: from psychotherapist to developmental psychopathologist and then to primary concerns with education and training, from psychologist to academic administrator and then back again, to forensic psychologist and on to whatever may come next. Through all of these shifts in focus, however, there has been one recurring theme--the appeal of being an assessment psychologist. The events that kept bringing me back to assessment, whatever else my focus at the time, are recorded in the story that follows. PMID:16171409

Weiner, Irving B

2005-10-01

456

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Disposal plan for embedded gravel, sand or stone. 644.505...Disposal of Standing Timber, Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior...

2013-07-01

457

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Disposal plan for embedded gravel, sand or stone. 644.505...Disposal of Standing Timber, Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior...

2009-07-01

458

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Disposal plan for embedded gravel, sand or stone. 644.505...Disposal of Standing Timber, Crops, and Embedded Gravel, Sand and Stone § 644.505 Disposal plan for embedded gravel, sand or stone. Prior...

2010-07-01

459

Sand encroachment by wind in Al-Hasa of Saudi Arabia  

NASA Astrophysics Data System (ADS)

Sand drift and sand dune movement rates in the study area are controlled by several major factors. These factors in descending order of importance are: wind characteristics (velocity, duration, and direction), mean sand grain size, dune size, sand volume available for transport, moisture content of the sand and density of vegetal cover. The objective of this study was to determine the rate of sand drift and sand dune movement as it is related to wind characteristics and mean sand grain size. Equipment to record wind characteristics was installed in the al-Hasa dune field during the period between February and June of 1980. Sand traps to measure the volume of sand moved and the direction from which it moved during this period were also installed at the project site. Sand caught in the various traps was analyzed and its statistical parameters such as the mean, sorting, skewness and kurtosis were determined. Rates of sand dune movement were determined.

Abolkhair, Y. M. S.

460

Freeze separation of salt contaminated melt water and sand wash water at snow storage and sand recycling facilities  

Microsoft Academic Search

Freeze separation is used to concentrate dilute salt in snow melt water and sand recycling wash water into concentrated brine that will be supplemented with crystal salt to treat recycled road sand. This reuse decreases the salt released to the environment. Field observations from a case study of a snow storage site in Edmonton, Albert, Canada confirmed freeze separation naturally

Christina Tatarniuk; Robert Donahue; David Sego

2009-01-01

461

Comparison of macrofaunal invertebrates in sand dollar ( Dendraster excentricus ) beds and in adjacent areas free of sand dollars  

Microsoft Academic Search

Abundances of macroinfaunal invertebrates in sand dollar (Dendraster excentricus) beds and in adjacent areas free of sand dollars were studied at 10 intertidal sites in the Pacific Northwest region of the USA and Canada. Each site was sampled once in late summer of 1977. There were no significant differences in overall diversity of species between the beds and adjacent areas;

A. L. Smith

1981-01-01

462

Wind tunnel measurements of adobe abrasion by blown sand: profile characteristics in relation to wind velocity and sand flux  

Microsoft Academic Search

Blown sand causes various damages, such as extensive abrasion to crops, structural wear of facilities and buildings, and abrasion of soil clods and clayey materials generating fine particulate matter. In this study, experiments conducted in a straight-line blowing wind tunnel confirmed field observations and provided useful information for understanding abrasion profiles created by sand drift. Abrasion rates of 20 adobe

Liu Lian-You; Gao Shang-Yu; Shi Pei-Jun; Li Xiao-Yan; Dong Zhi-Bao

2003-01-01

463

Measurement of saltation process over gobi and sand dunes in the Taklimakan desert, China, with newly developed sand particle counter  

Microsoft Academic Search

The Japan-Sino joint project, Aeolian Dust Experiment on Climate impact (ADEC), was initiated in April 2000 in order to understand the aeolian dust impact on climate via radiative forcing. As a part of the ADEC project, we have conducted field research in a sand dune and a gobi (i.e., a desert in which the soil surface consists of sand and

Masao Mikami; Yutaka Yamada; Masahide Ishizuka; Taminoe Ishimaru; Weidong Gao; Fanjiang Zeng

2005-01-01

464

The fluctuation property of blown sand particles and the wind-sand flow evolution studied by numerical method.  

PubMed

Sand particles blown by wind cause serious environmental problems and many researchers are trying to understand the dynamic properties of blown sand better. But the existing numerical approaches have not been able to simulate many important characteristics of wind-sand flow. In this paper, the evolution and fluctuation properties of blown sand at a dynamic steady state are investigated by using a more effective method. Using the LES (large eddy simulation) method for air phase movement and the DEM (discrete element method) for solid phase movement along with the existing particle-bed splashing function, we have characterized the whole movement property of the wind-sand system. The results indicate that the saturation time decreases with the inlet friction velocity, and it gradually reaches the shortest saturation time of about 1s; the saturation length, which is about 14 m at the usual wind velocity, first increases with wind velocity and then reaches a plateau; within the saturation length, the sand transport rate at different positions varies with time; the sand transport rate of the stable wind-sand flow is non-uniform with distance downwind and time, and has a notable correlation with the inflow friction velocity. PMID:21626346

Ma, G S; Zheng, X J

2011-05-30

465

Field observations on the protective effect of semi-buried checkerboard sand barriers  

Microsoft Academic Search

Semi-buried checkerboard sand barriers, especially those made of wheat straw and rolled reeds, are a widely used, cheap and practical sand stabilization measure in China. Such sand barriers can halt near-surface sand flow by increasing underlying surface roughness, reducing near-surface wind velocity, and weakening sand transportation intensity, thereby stabilizing the sand surface. Vortex actions within the cells of the grid

Jianjun Qu; Ruiping Zu; Kecun Zhang; Haiyan Fang

2007-01-01

466

White matter damage and cognitive impairment after traumatic brain injury.  

PubMed

White matter disruption is an important determinant of cognitive impairment after brain injury, but conventional neuroimaging underestimates its extent. In contrast, diffusion tensor imaging provides a validated and sensitive way of identifying the impact of axonal injury. The relationship between cognitive impairment after traumatic brain injury and white matter damage is likely to be complex. We applied a flexible technique-tract-based spatial statistics-to explore whether damage to specific white matter tracts is associated with particular patterns of cognitive impairment. The commonly affected domains of memory, executive function and information processing speed were investigated in 28 patients in the post-acute/chronic phase following traumatic brain injury and in 26 age-matched controls. Analysis of fractional anisotropy and diffusivity maps revealed widespread differences in white matter integrity between the groups. Patients showed large areas of reduced fractional anisotropy, as well as increased mean and axial diffusivities, compared with controls, despite the small amounts of cortical and white matter damage visible on standard imaging. A stratified analysis based on the presence or absence of microbleeds (a marker of diffuse axonal injury) revealed diffusion tensor imaging to be more sensitive than gradient-echo imaging to white matter damage. The location of white matter abnormality predicted cognitive function to some extent. The structure of the fornices was correlated with associative learning and memory across both patient and control groups, whilst the structure of frontal lobe connections showed relationships with executive function that differed in the two groups. These results highlight the complexity of the relationships between white matter structure and cognition. Although widespread and, sometimes, chronic abnormalities of white matter are identifiable following traumatic brain injury, the impact of these changes on cognitive function is likely to depend on damage to key pathways that link nodes in the distributed brain networks supporting high-level cognitive functions. PMID:21193486

Kinnunen, Kirsi Maria; Greenwood, Richard; Powell, Jane Hilary; Leech, Robert; Hawkins, Peter Charlie; Bonnelle, Valerie; Patel, Maneesh Chandrakant; Counsell, Serena Jane; Sharp, David James

2010-12-29

467

Extending the Bounds of Race and Racism: Indigenous Women and the Persistence of the Black-White Paradigm of Race  

ERIC Educational Resources Information Center

|In this article, the author illustrates how the dominant Black-White binary paradigm of race in the United States situates Indigenous women as either racialized Others or White Others in the context of a predominantly White university. Race and racism are thus salient in the lives of Indigenous students in multiple and complex ways--ways which…

Castagno, Angelina E.

2005-01-01

468

Extending the Bounds of Race and Racism: Indigenous Women and the Persistence of the Black-White Paradigm of Race  

ERIC Educational Resources Information Center

In this article, the author illustrates how the dominant Black-White binary paradigm of race in the United States situates Indigenous women as either racialized Others or White Others in the context of a predominantly White university. Race and racism are thus salient in the lives of Indigenous students in multiple and complex ways--ways which are…

Castagno, Angelina E.

2005-01-01

469

Genetic features of soils on sorted sand deposits of different origins in the Kola Peninsula  

NASA Astrophysics Data System (ADS)

Differences in the chemical composition of soils developed from sorted sands of different origins are revealed. The iron-illuvial podzols on rich glaciofluvial and marine sands are characterized by well-pronounced Al-Fe-humus differentiation of the Si, Al, and Fe in the soil profile. These soils are relatively similar in their bulk elemental composition. The difference between them is seen in the degree of differentiation of the soil profiles; it is stronger in the soils developed from glaciofluvial deposits. This is particularly true with respect to the oxalate-soluble iron and aluminum hydroxides. The deposits derived from the red-colored Tersk sandstone and processed by the sea (in the coastal zone of the White Sea) have the poorest chemical composition. In the soils developed from them, the differentiation of oxalate-soluble compounds is slightly pronounced (for Fe) or completely absent (for Si and Al). These soils can be classified as podzolized ferruginous red-colored psammozems (within the order of poorly developed soils) with the following horizons: O-Ce-Cf-C. The Ce horizon has the features of podzolization, and the Cf horizon has some features attesting to the illuvial accumulation of Fe. The profile of these soils inherits a reddish tint from the parent material.

Pereverzev, V. N.

2009-09-01

470

Electrokinetics dependence on water-content in sand  

NASA Astrophysics Data System (ADS)

The electrokinetic potential results from the coupling between the water flow and the electrical current because of the presence of ions within water. This coupling is well described in fluid-saturated media, however its behavior under unsaturated flow conditions is still discussed. We propose here an experimental approach which can clearly describe streaming potential variations in unsaturated conditions. Several drainage experiments have been performed within a column filled with a clean sand. Streaming potential measurements are combined to capillary pressure and to water content measurements each 10 centimeter along the column. In order to model hydrodymanics during each experiment, we solve Richards equation in an inverse way which allows us to establish the relation between hydraulic conductivity and water content, and retention relation. The electrokinetic coefficient C shows a more complex behavior than it was previously reported and can not be fitted by the existing models. We show that the normalized electrokinetic coefficient increases first when water saturation decreases from 100% to about 80% - 95%, and then decreases as the water saturation decreases, whereas all previous works described a unifrom decrease of the normalized electrokinetic coefficient as water saturation decreases. We delimited two water saturation domains, and deduced two different empirical laws describing the evolution of the electrokinetic coefficient in unsaturated conditions. Finally, electrical potentials data from four different drainage experiments and hydrodynamics were jointly inversed, including electrical conductivity measurements in order to find a robust description of the electrokinetic coefficient behavior in unsaturated conditions.

Allègre, V.; Lehmann, F.; Jouniaux, L.; Sailhac, P.; Matthey, P.

2009-12-01

471

Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate  

USGS Publications Warehouse

The mechanical behavior of hydrate-bearing sediments subjected to large strains has relevance for the stability of the seafloor and submarine slopes, drilling and coring operations, and the analysis of certain small-strain properties of these sediments (for example, seismic velocities). This study reports on the results of comprehensive axial compression triaxial test