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Sample records for calvert bluff formation

  1. The origin and distribution of HAPs elements in relation to maceral composition of the A1 lignite bed (Paleocene, Calvert Bluff Formation, Wilcox Group), Calvert mine area, east-central Texas

    USGS Publications Warehouse

    Crowley, S.S.; Warwick, P.D.; Ruppert, L.F.; Pontolillo, J.

    1997-01-01

    The origin and distribution of twelve potentially Hazardous Air Pollutants (HAPs; As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb Sb, Se, and U) identified in the 1990 Clean Air Act Amendments were examined in relation to the maceral composition of the A1 bed (Paleocene, Calvert Bluff Formation, Wilcox Group) of the Calvert mine in east-central Texas. The 3.2 m-thick A1 bed was divided into nine incremental channel samples (7 lignite samples and 2 shaley coal samples) on the basis of megascopic characteristics. Results indicate that As, Cd, Cr, Ni, Pb, Sb, and U are strongly correlated with ash yield and are enriched in the shaley coal samples. We infer that these elements are associated with inorganic constituents in the coal bed and may be derived from a penecontemporaneous stream channel located several kilometers southeast of the mining block. Of the HAPs elements studied, Mn and Hg are the most poorly correlated to ash yield. We infer an organic association for Mn; Hg may be associated with pyrite. The rest of the trace elements (Be, Co, and Se) are weakly correlated with ash yield. Further analytical work is necessary to determine the mode of occurrence for these elements. Overall, concentrations of the HAPs elements are generally similar to or less than those reported in previous studies of lignites of the Wilcox Group, east-central region, Texas. Petrographic analysis indicates the following ranges in composition for the seven lignite samples: liptinites (5-8%), huminites (88-95%), and inertinites (trace amounts to 7%). Samples from the middle portion of the A1 bed contain abundant crypto-eugelinite compared to the rest of the samples; this relationship suggests that the degradation of plant material was an important process during the development of the peat mire. With the exception of Hg and Mn, relatively low levels of the HAPs elements studied are found in the samples containing abundant crypto-eugelinite. We infer that the peat-forming environment for this portion

  2. Slope evolution at the Calvert Cliffs, Maryland -- measuring the change from eroding bluffs to stable slopes

    USGS Publications Warehouse

    Herzog, Martha; Larsen, Curtis E.; McRae, Michele

    2002-01-01

    Despite a long history of geomorphic studies, it is difficult to ascertain the time required for slopes to change from near vertical exposures to relatively stable slopes due to inadequate age control. Actively eroding coastal bluffs along the western shore of the Chesapeake Bay provide a key for understanding the centennial-scale development of stable slopes from eroding bluff faces. The Calvert Cliffs are composed of sandy silts, silty sands, and clayey silts of Miocene-age. Active wave erosion at the bluff toes encourages rapid sloughing from bluff faces and maintains slope angles of 70-80 degrees and relatively constant bluff-retreat rates. Naturally stabilized slopes are preserved as a fossil bluff line inland from a prograding cuspate foreland at Cove Point. The foreland is migrating southward at a rate of ca. 1.5 m/yr. As it moves south, it progressively protects bluffs from wave action as new beaches are deposited at their toes. Wave erosion is reinitiated at the northern end of the complex as the landform passes. An incremental record of slope change is preserved along the fossil bluff line. 14C dating of swales between beach ridges shows the complex to span 1700 years of progressive migration history. We hypothesized that slopes would change from steep, eroding faces to low-angle slopes covered with vegetation and sought to document the rate of change. Our team measured slope angles at intervals along the fossil bluff line and dated profiles by interpolating 14C ages of adjacent beach ridges. There was no progressive decrease in slope with age. All slopes along the fossil bluff line were 30-40 degrees with a mean of 35 degrees. Constancy in slope angle suggests that steep, actively eroding bluffs were quickly changed to stable slopes by landslides and slumping once they were protected. Given the accuracy of our age control, we conclude that the time required to attain a stable slope under natural processes is less than one century. This indicates that

  3. Coal geology of the Paleocene-Eocene Calvert Bluff Formation (Wilcox Group) and the Eocene Manning Formation (Jackson Group) in east-central Texas; field trip guidebook for the Society for Organic Petrology, Twelfth Annual Meeting, The Woodlands, Texas, August 30, 1995

    USGS Publications Warehouse

    Warwick, Peter D.; Crowley, Sharon S.

    1995-01-01

    The Jackson and Wilcox Groups of eastern Texas (fig. 1) are the major lignite producing intervals in the Gulf Region. Within these groups, the major lignite-producing formations are the Paleocene-Eocene Calvert Bluff Formation (Wilcox) and the Eocene Manning Formation (Jackson). According to the Keystone Coal Industry Manual (Maclean Hunter Publishing Company, 1994), the Gulf Coast basin produces about 57 million short tons of lignite annually. The state of Texas ranks number 6 in coal production in the United States. Most of the lignite is used for electric power generation in mine-mouth power plant facilities. In recent years, particular interest has been given to lignite quality and the distribution and concentration of about a dozen trace elements that have been identified as potential hazardous air pollutants (HAPs) by the 1990 Clean Air Act Amendments. As pointed out by Oman and Finkelman (1994), Gulf Coast lignite deposits have elevated concentrations of many of the HAPs elements (Be, Cd, Co, Cr, Hg, Mn, Se, U) on a as-received gm/mmBtu basis when compared to other United States coal deposits used for fuel in thermo-electric power plants. Although regulations have not yet been established for acceptable emissions of the HAPs elements during coal burning, considerable research effort has been given to the characterization of these elements in coal feed stocks. The general purpose of the present field trip and of the accompanying collection of papers is to investigate how various aspects of east Texas lignite geology might collectively influence the quality of the lignite fuel. We hope that this collection of papers will help future researchers understand the complex, multifaceted interrelations of coal geology, petrology, palynology and coal quality, and that this introduction to the geology of the lignite deposits of east Texas might serve as a stimulus for new ideas to be applied to other coal basins in the U.S. and abroad.

  4. Frequency of effective wave activity and the recession of coastal bluffs: Calvert Cliffs, Maryland

    USGS Publications Warehouse

    Wilcock, P.R.; Miller, D.S.; Shea, R.H.; Kerkin, R.T.

    1998-01-01

    The Calvert Cliffs, Chesapeake Bay, Maryland, USA, erode by direct wave undercutting or by freeze/thaw erosion accompanied by wave removal of slope debris. Directly undercut slopes recede more rapidly, with long-term rates exceeding 1.0 m/yr; freeze/thaw slopes recede at rates approaching 0.5 m/yr. The frequency of wave height and water level at the shoreline is estimated for eleven sites based on a 37-year wind record, estimates of storm surge, offshore wave geometry, nearshore wave transformation, and breaking wave type. Locations experiencing the largest slope recession are not uniformly those with the largest cumulative wave energy; the resistance to erosion of the slope toe must also be accounted for. An index of relative wave strength is defined as the ratio of wave pressure T and the cohesive strength S of the slope material. For the Calvert Cliffs, a minimum relative wave strength for initiating erosion of intact material is 0.05 < T/S < 0.1. A cumulative duration of ???50 hours per year for T/S ??? 0.1 distinguishes undercut and nonundercut slopes and recession rates greater or lesser than 0.5 m/yr. The relative wave strength index may be used to identify sites at risk of increased erosion. At one site with a small historical erosion rate, the loss of a protective beach and associated decrease in toe elevation caused a positive shift in the frequency of large T/S. Direct wave undercutting and increased slope recession may be anticipated at this site, as indicated by the development of an undercut notch during the course of the study.

  5. The physical conditions indicated by the flora of the Calvert formation

    USGS Publications Warehouse

    Berry, Edward Wilber

    1917-01-01

    The object of the present paper is to give a summary of the small flora preserved in the Miocene diatomaceous beds of the Calvert formation in the District of Columbia and Virginia, and more especially to discuss its bearing on the physical conditions of the Calvert epoch. Subsequent to the middle Eocene the next abundant marine fauna preserved along the middle Atlantic coast is that of the Calvert formation of the Chesapeake group. Although Miocene faunas so low in the stratigraphic column are known south of Virginia only in the vicinity of Porters Landing, Savannah River, closely related but younger Miocene faunas extend southward at least as far as Florida, where the containing formation rests unconformably on beds in which occur the warmer-water faunas of the Apalachicola group.

  6. Wind Erosion and Dune Formation on High Frozen Bluffs

    NASA Technical Reports Server (NTRS)

    Marsh, W. M.; Marsh, B. D.

    1984-01-01

    Frost penetration increases upslope on barren, windswept bluffs in cold environments. Along the south shore of Lake Superior, near the brow of 100 m high bluffs it typically exceeds 5 m. Frost increases the shear strength of damp sand to a level comparable to that of concrete, making winter slopes highly stable despite undercutting by waves and ground-water sapping along the footslope. Sublimation of interparticle ice in the slope face increases with wind speed and lower vapor pressures. The cold and dry winter winds of Lake Superior ablate these slopes through loss of binding ice. Wind erosion rates, based on measurements of sand accumulation on the forest floor downwind of the brow, show most airborne sand falls out within several meters of the brow, forming a berm 1 to 3 m high after many years. The spatial pattern of sand deposition, however, varies considerably over distances of several hundred meters along the top bluffs in response to frost conditions and the build-up of gravel lag on the slope face, sand exposure from mass movements, and local aerodynamics of the crest slope. The formation of perched sand dunes in the Great Lakes region is clearly related to wind erosion of sand from high bluffs in winter. Broadly similar processes may operate on Mars.

  7. Stratigraphy and Facies of Cretaceous Schrader Bluff and Prince Creek Formations in Colville River Bluffs, North Slope, Alaska

    USGS Publications Warehouse

    Flores, Romeo M.; Myers, Mark D.; Houseknecht, David W.; Stricker, Gary D.; Brizzolara, Donald W.; Ryherd, Timothy J.; Takahashi, Kenneth I.

    2007-01-01

    Stratigraphic and sedimentologic studies of facies of the Upper Cretaceous rocks along the Colville River Bluffs in the west-central North Slope of Alaska identified barrier shoreface deposits consisting of vertically stacked, coarsening-upward parasequences in the Schrader Bluff Formation. This vertical stack of parasequence deposits represents progradational sequences that were affected by shoaling and deepening cycles caused by fluctuations of sea level. Further, the vertical stack may have served to stabilize accumulation of voluminous coal deposits in the Prince Creek Formation, which formed braided, high-sinuosity meandering, anastomosed, and low-sinuosity meandering fluvial channels and related flood plain deposits. The erosional contact at the top of the uppermost coarsening-upward sequence, however, suggests a significant drop of base level (relative sea level) that permitted a semiregional subaerial unconformity to develop at the contact between the Schrader Bluff and Prince Creek Formations. This drop of relative sea level may have been followed by a relative sea-level rise to accommodate coal deposition directly above the unconformity. This rise was followed by a second drop of relative sea level, with formation of incised valley topography as much as 75 ft deep and an equivalent surface of a major marine erosion or mass wasting, or both, either of which can be traced from the Colville River Bluffs basinward to the subsurface in the west-central North Slope. The Prince Creek fluvial deposits represent late Campanian to late Maastrichtian depositional environments that were affected by these base level changes influenced by tectonism, basin subsidence, and sea-level fluctuations.

  8. Pumice in the interglacial Whidbey Formation at Blowers Bluff, central Whidbey Island, WA, USA

    USGS Publications Warehouse

    Dethier, D.P.; Dragovich, J.D.; Sarna-Wojcicki, A. M.; Fleck, R.J.

    2008-01-01

    A new 40Ar/39Ar age of 128??9 ka and chemical analyses of pumice layers from interglacial alluvium at Blowers Bluff, Whidbey Island, WA, show that the deposits are part of the Whidbey Formation, a widespread, mainly subsurface unit. Glass chemistry of the dated dacitic pumice does not match any analyzed northern Cascade source, but upper Pleistocene dacites from Glacier Peak and early Pleistocene silicic rocks from the Kulshan caldera are chemically similar. The chemistry of pumiceous dacite in younger units, including the latest Pleistocene Partridge Gravel, is similar to that of the dated material. The deep troughs of the modern northern Puget lowland must have been filled during deposition of the Whidbey Formation, allowing volcanic-rich sediment to reach what is now Whidbey Island. Topographic analysis of LIDAR images demonstrates that extensive erosion occurred during latest Pleistocene ice retreat. The Partridge Gravel likely records subglacial fluvial erosion along an ice tunnel and ice-marginal deposition into adjacent marine waters. Pumice in the Partridge Gravel probably was reworked from stratigraphically and topographically lower deposits, including those at Blowers Bluff. ?? 2007 Elsevier Ltd and INQUA.

  9. Bluff formation and long-term recession rates, southwestern Lake Michigan

    SciTech Connect

    Rovey, C.W. II )

    1992-01-01

    Where eroding cohesive sediments are present, Lake Michigan bluffs range up to 140 ft. in height and expose multiple stratigraphic units. According to the model presented here, bluffs form as a wave cut terrace erodes inland from a point near the original shoreline. The erosion plane is nearly horizontal, in contrast with the eastward dip of the glacial units inherited from underlying bedrock. Therefore, terraces eroding inland (west) produce progressively higher bluffs and expose successively older units at the toe and beneath the lake. This process repeated several times as lake levels sequentially dropped to their modern stage. The initial modern shoreline, and hence the width of the wave cut terrace, was determined from 4 offshore seismic profiles. It is picked as an inflection point in the slope of the lake bed, occurring offshore of dipping reflectors intersecting the lake bottom. The calculated average recession rate over the 2,500 year duration of the modern stage is 5 ft/yr in contrast to average rates of 2 ft/yr measured over the last century. Thus rates decrease through time as the terrace widens and wave energy is damped. By correlating bluff height to amount of recession of modern bluffs, a third rate of 12 ft/yr of the first 800 years of a recession is calculated for relict bluffs formed at the Nipissing II level. The 3 rates define a steeply decaying exponential curve in early stages of bluff retreat, flattening into a nearly linear function after 1,000 years.

  10. Sentinel Hill Core Test 1: Facies Descriptions and Stratigraphic Reinterpretations of the Prince Creek and Schrader Bluff Formations, North Slope, Alaska

    USGS Publications Warehouse

    Flores, Romeo M.; Stricker, Gary D.; Decker, Paul L.; Myers, Mark D.

    2007-01-01

    The Sentinel Hill Core Test 1 well penetrated an intertonguing sequence of (1) the marine Schrader Bluff Formation in the depth intervals 950?1,180 ft and 690?751 ft, which consists of shoreface and offshore deposits that accumulated along a storm-dominated, barred shoreline; and (2) the nonmarine Prince Creek Formation in the depth intervals 751?950 ft and surface to 690 ft, which consists of fluvial channel, crevasse splay, backswamp, and ash fall deposits. The strata range in age from early Campanian to early Maastrichtian. An erosional contact at a depth of 690 ft at the base of the upper unit of the Prince Creek Formation is interpreted as a major regional sequence boundary, and the overlying conglomeratic fluvial channel deposits are interpreted to have accumulated in a paleovalley. In its more proximal reaches along the Colville River, channels of this paleovalley cut down 75 ft into the lowermost Prince Creek Formation and the uppermost Schrader Bluff Formation. Farther offshore, the equivalent surface to the aforementioned paleovalley appears to be a subtle discontinuity between middle and lower Schrader Bluff Formation shelfal marine strata. Still farther offshore, the equivalent paleovalley surface is interpreted as a marine mass-wasting surface that locally cuts through the lowermost Schrader Bluff Formation and into the underlying Seabee Formation.

  11. Bluff evolution along coastal drumlins: Boston Harbor Islands, Massachusetts

    USGS Publications Warehouse

    Himmelstoss, E.A.; FitzGerald, D.M.; Rosen, P.S.; Allen, J.R.

    2006-01-01

    A series of partially drowned drumlins forms the backbone of the inner islands within Boston Harbor. The shoreline of these rounded glacial deposits is composed of actively retreating bluffs formed by continual wave attack. Comparisons of bluffs reveal variability in their height and lateral extent, as well as in the dominant mechanism causing their retreat. Two processes are responsible for bluff erosion and yield distinct bluff morphologies: (1) wave attack undercuts the bluff and causes episodic slumping, yielding planar bluff slopes, and (2) subaerial processes such as rainfall create irregular slopes characterized by rills and gullies. We propose a model of drumlin bluff evolution that is based on processes of erosion and physical characteristics such as bluff height, slope morphology, and the orientation of the bluff with respect to the long axis of the drumlin and its topographic crest. The four phases of drumlin bluff evolution consist of (1) initial formation of bluff, with retreat dominated by wave notching and slumping processes; (2) rill and gully development as bluff heights exceed 10 m and slumped sediment at bluff base inhibits wave attack; (3) return of wave notching and slumping as bluff heights decrease; and (4) final development of boulder retreat lag as last remnants of drumlin are eroded by wave action. These phases capture the important physical processes of drumlin evolution in Boston Harbor and could apply to other eroding coastal drumlin deposits.

  12. 6. SOUTHEAST ABUTMENT AT CALVERT STREET, SHOWING LEON HERMANT ALLEGORICAL ...

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

    6. SOUTHEAST ABUTMENT AT CALVERT STREET, SHOWING LEON HERMANT ALLEGORICAL RELIEF OF TRANSPORTATION BY AUTOMOBILE - Calvert Street Bridge, Spanning Rock Creek & Potomac Parkway, Washington, District of Columbia, DC

  13. Hemiacodon engardae, a new species of omomyid primate from the earliest Uintan Turtle Bluff Member of the Bridger Formation, southwestern Wyoming, USA.

    PubMed

    Murphey, Paul C; Dunn, Rachel H

    2009-08-01

    In this paper, we describe a new species of Hemiacodon known only from University of Colorado Museum Loc. 92189 (Donna's Locality) in the Turtle Bluff Member of the Bridger Formation, Green River Basin, southwestern Wyoming. Donna's locality has yielded a diverse mostly small-bodied mammalian assemblage of Bridgerian and first appearance Uintan mammalian taxa, as well as range-through taxa. Together with H. engardae sp. nov., the faunal assemblage from Donna's Locality and more recently discovered localities in the same stratigraphic interval provides the first conclusive paleontological evidence of an earliest Uintan age (Ui1A biochron) for the Turtle Bluff Member of the Bridger Formation. The new species is represented by a sample of 11 specimens consisting of well-preserved upper and lower premolars and lower molars. H. engardae is distinct from H. gracilis on the basis of overall larger size as well as a combination of features of the premolars and molars related to a greater development of shearing crests. This suggests that H. engardae may have incorporated more foliage into its diet than the Bridgerian species, H. gracilis. PMID:19625072

  14. 75 FR 66802 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-29

    ... COMMISSION Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2... Regulatory Commission (the Commission) has granted the request of Calvert Cliffs Nuclear Power Plant, LLC... Operating License Nos. DPR-53 and DPR-69 for the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and...

  15. Observations of Permafrost Bluff Failure Processes, Barter Island, NE Alaska

    NASA Astrophysics Data System (ADS)

    Erikson, L. H.; Richmond, B. M.; Gibbs, A.; Jones, B.

    2011-12-01

    Arctic coast permafrost bluffs are extremely vulnerable to increased thaw, erosion, and landward retreat in a warming climate. Here, we report on permafrost bluff retreat processes based on field observations of bluff geology and morphology during the summers of 2010 and 2011 combined with historical analyses of bluff retreat rates from the mid 1940s to the present for Barter Island, NE Alaska. Field data collected included GPS surveys of bluff position and morphology, geologic mapping including stratigraphy, sediment size and composition, ice content, nearshore bathymetry, and temperature gradients recorded by thermistor arrays. Failure mechanisms are the direct causes of failures and include wave action, water flow (both surface and groundwater), freeze/thaw impacts, and surficial weathering. Failure modes are the processes by which the failures occur such as undercutting (notching) and oversteepening of the bluff face, retrogressive thaw slumping, rotational failures, block falls, and gullying. Processes of failure observed along the Barter Island bluffs vary both temporally with seasonal changes in temperature and sea-ice conditions, and spatially associated with variations in bluff height and composition. In the spring and early summer, sediment-entrained land-fast ice recedes, removing and reworking sediment from the bluff and foreshore. Snow melt induces surface runoff and gullying, and is accompanied by thawing of the bluff face which begins to produce debris avalanches and small alluvial fans at the base of the bluffs where a backbeach is present. During the summer months, when sea-ice has retreated from the coast, thermo-erosional niching and mechanical notch formation occurs due to small storm waves and elevated water levels in response to winds and pressure differences. As bluff-face thawing continues large thaw slump failures and block falls begin to develop. In late summer and fall, before the sea ice returns, extra-tropical storms lead to increased

  16. 76 FR 39908 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... participating under 10 CFR 2.315(c), must be filed in accordance with the NRC E-Filing rule (72 FR 49139, August... COMMISSION Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2.... DPR-53 and DPR-69, for the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (CCNPP),...

  17. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland. 165.505 Section 165.505 Navigation and... Areas Fifth Coast Guard District § 165.505 Security Zone; Calvert Cliffs Nuclear Power Plant,...

  18. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland. 165.505 Section 165.505 Navigation and... Areas Fifth Coast Guard District § 165.505 Security Zone; Calvert Cliffs Nuclear Power Plant,...

  19. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland. 165.505 Section 165.505 Navigation and... Areas Fifth Coast Guard District § 165.505 Security Zone; Calvert Cliffs Nuclear Power Plant,...

  20. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland. 165.505 Section 165.505 Navigation and... Areas Fifth Coast Guard District § 165.505 Security Zone; Calvert Cliffs Nuclear Power Plant,...

  1. 76 FR 4391 - Calvert Cliffs Nuclear Power Plant, LLC, Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Calvert Cliffs Nuclear Power Plant, LLC, Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2; Exemption 1.0 Background Calvert Cliffs Nuclear Power Plant, LLC, the licensee, is the holder of Facility Operating License Nos. DPR-53 and DPR-69...

  2. Planar Deformation Feature Orientations and Distribution in Quartz Grains from the Carrizo Sand Formation in South Texas: Relation to the Bee Bluff Structure

    NASA Astrophysics Data System (ADS)

    Jurena, D. J.; French, B. M.; Gaffey, M. J.

    2001-03-01

    The Bee Bluff structure has been debated as to its possible impact origin. We have found PDF's there in a higher concentration than in other locations and having dominant orientation patterns consistent with impacts in porous sedimentary rocks.

  3. Historic bluff retreat and stabilization at Flag Harbor, Chesapeake Bay, Maryland

    USGS Publications Warehouse

    Clark, Inga; Larsen, Curtis E.; McRae, Michele

    2002-01-01

    Studies of bluff erosion and slope stability along the western shore of Chesapeake Bay suggest relative evolution from steep, eroding coastal bluffs to stable slopes at angles of repose ca. 35 degrees over decades. Because of the dating methods in those studies, it was impossible to precisely define rates of change. The present study provides historic age control. A pair of small harbor structures were constructed in the early 1950's at Chesapeake Beach, MD to maintain a dredged channel to a small marina occupying a ravine in the Calvert Cliffs. Prior to construction, this section of shoreline was comprised of eroding steep bluffs cut into Miocene-age sediments. Downdrift erosion is now apparent south of the structures as is updrift deposition behind the northern jetty. Since construction the updrift sand body has prograded northward and progressively deposited protective beaches along the toes of the bluffs. Former eroding bluffs nearest the harbor are now stable, vegetated slopes at angles near 35 degrees. Slope angles widen to the north and to the northern limit of the sand body. Beyond this are eroding bluffs standing at angles of 70-80 degrees. The relative time required for eroding bluffs to reach stability is estimated by interpolating the distance and time for the sand body to prograde northward since harbor construction. We measured slope angles at intervals northward from the updrift structure for a distance of 2000 feet. A least squares regression of slope angle vs distance showed progressive decrease in angle from north to south. Actively eroding 70-80 degree bluffs gave way to vegetated, but slumping slopes, and finally to stable 35-degree slopes at the harbor. A relationship between time and distance along the shore allowed us to estimate a stabilization time for this location of 35-40 years. The shortness of this time scale allows us to suggest that attempts to artificially stabilize eroding bluffs along this coast is not a simple task of protecting

  4. A model of tephra dispersal from an early Palaeogene shallow submarine Surtseyan-style eruption(s), the Red Bluff Tuff Formation, Chatham Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Sorrentino, Leonor; Stilwell, Jeffrey D.; Mays, Chris

    2014-03-01

    The Red Bluff Tuff Formation, an early Palaeogene volcano-sedimentary shallow marine succession from the Chatham Islands (New Zealand), provides a unique framework, in eastern 'Zealandia', to explore tephra dispersal processes associated with ancient small phreatomagmatic explosions (i.e. Surtseyan-style eruptions). Detailed sedimentological mapping, logging and sampling integrated with the results of extensive laboratory analyses (i.e. grain-size, componentry and applied palaeontological methods) elucidated the complex mechanisms of transport and deposition of nine identified resedimented fossiliferous volcaniclastic facies. These facies record the subaqueous reworking and deposition of tephra from the erosion and degradation of a proximal, entirely submerged ancient Surtseyan volcanic edifice (Cone II). South of this volcanic cone, the lowermost distal facies provides significant evidence of deposition as water-supported volcanic- or storm-driven mass flows (e.g. turbidity currents and mud/debris flows) of volcaniclastic and bioclastic debris, whereas the uppermost distal facies exhibit features of tractional sedimentary processes caused by shallow subaqueous currents. Further north, within the proximity of the volcanic edifice, the uppermost facies are represented by an abundant, diverse, large, and well preserved in situ fauna of shallow marine sessile invertebrates (e.g. corals and sponges) that reflect the protracted biotic stabiliszation and rebound following pulsed volcanic events. Over a period of time, these stable and wave-eroded volcanic platforms were inhabited by a flourishing and diversifying marine community of benthic and sessile pioneers (corals, bryozoans, molluscs, brachiopods, barnacles, sponges, foraminifera, etc.). This succession exhibits a vertical progression of sedimentary structures (i.e. density, cohesive and mass flows, and cross-bedding) and our interpretations indicate a shallowing upwards succession. This study reports for the first

  5. 77 FR 47121 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Units 1 and 2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-07

    ... Consideration (73 FR 17148; March 31, 2008), states that ``Plant emergencies are extraordinary circumstances... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Units 1 and...

  6. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland. 165.505 Section 165.505 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED...

  7. Geohydrology and simulation of ground-water flow in the aquifer system near Calvert City, Kentucky

    USGS Publications Warehouse

    Starn, J.J.; Arihood, L.D.; Rose, M.F.

    1995-01-01

    The U.S. Geological Survey, in cooperation with the Kentucky Natural Resources and Environmental Protection Cabinet, constructed a two-dimensional, steady-state ground-water-flow model to estimate hydraulic properties, contributing areas to discharge boundaries, and the average linear velocity at selected locations in an aquifer system near Calvert City, Ky. Nonlinear regression was used to estimate values of model parameters and the reliability of the parameter estimates. The regression minimizes the weighted difference between observed and calculated hydraulic heads and rates of flow. The calibrated model generally was better than alternative models considered, and although adding transmissive faults in the bedrock produced a slightly better model, fault transmissivity was not estimated reliably. The average transmissivity of the aquifer was 20,000 feet squared per day. Recharge to two outcrop areas, the McNairy Formation of Cretaceous age and the alluvium of Quaternary age, were 0.00269 feet per day (11.8 inches per year) and 0.000484 feet per day (2.1 inches per year), respectively. Contributing areas to wells at the Calvert City Water Company in 1992 did not include the Calvert City Industrial Complex. Since completing the fieldwork for this study in 1992, the Calvert City Water Company discontinued use of their wells and began withdrawing water from new wells that were located 4.5 miles east-southeast of the previous location; the contributing area moved farther from the industrial complex. The extent of the alluvium contributing water to wells was limited by the overlying lacustrine deposits. The average linear ground-water velocity at the industrial complex ranged from 0.90 feet per day to 4.47 feet per day with a mean of 1.98 feet per day.

  8. A Bluff-Bidding Exercise

    ERIC Educational Resources Information Center

    Meister, J. Patrick

    2011-01-01

    Consider an auction in which one potential buyer wishes to participate, but the other potential buyer would rather the bidding not start. However, once bidding starts, the reluctant firm participates (submits "bluff bids") simply to make the eventual winner pay more. This incentive exists when the marginal effect of the winning bid is to increase…

  9. Gosses Bluff impact structure, Australia.

    NASA Technical Reports Server (NTRS)

    Milton, D. J.; Barlow, B. C.; Brown, A. R.; Glikson, A. Y.; Manwaring, E. A.; Moss, F. J.; Sedmik, E. C. E.; Van Son, J.; Brett, R.; Young, G. A.

    1972-01-01

    A comprehensive study has been carried out of the Gosses Bluff structure in Central Australia, which is a typical cryptoexplosion structure. The study included detailed geologic mapping, and seismic reflection and refraction, gravity, aeromagnetic, and ground magnetic surveys. It is concluded that the structure is an eroded crater formed by a single nearly instantaneous shock event, and that the event can be explained only by impact.

  10. Site Visit to Calvert County, Maryland ARC Family Support Services.

    ERIC Educational Resources Information Center

    Bersani, Hank A., Jr.

    The site visit report describes the Family Support Services program run by the Calvert County (Maryland) Association for Retarded Citizens. The program's goal is to prevent any person 21 years of age or younger from being institutionalized. It provides respite care services, specialized family support, and integrated day care for approximately 50…

  11. Red Bluff, Marion County, Mississippi: a Citronelle braided-stream deposit

    SciTech Connect

    Smith, M.L.; Meylan, M.A.

    1983-09-01

    Red Bluff is an erosional escarpment located on the western margin of the Pearl River flood plain in northwestern Marion County, Mississippi. The sand grains are composed primarily of quartz, with small amounts of heavy minerals and feldspar. The gravel is composed of varying percentages of chert, flint, jasper, rip-up clasts, quartz, and tripoli, including a small fraction of silicified Paleozoic fossils. Grain-size analysis of the sediment and investigation of the sedimentary structures suggest a braided-fluvial environment of deposition. The most conspicuous sedimentary structures at Red Bluff are graded bedding, low-angle to medium-angle cross-bedding, and well-developed paleochannels. A statistical comparison (discriminant analysis) of the seven most abundant heavy minerals of Red Bluff, with the same suite of heavy minerals found at the type section of the Citronelle Formation (Pliocene-Pleistocene), and outcrops of a known Miocene coarse clastic unit indicates a correlation of Red Bluff to the Citronelle Formation. These heavy minerals are kyanite, staurolite, rutile, tourmaline, zircon, black opaques (primarily ilmenite and magnetite), and white opaques (primarily leucoxene). The suite of heavy minerals present at Red Bluff belongs to the east Gulf province. This metamorphic assemblage of heavy minerals implies the source area of the sediments at Red Bluff to be the southern Appalachians. The silicified pebble-size Devonian-Mississippian fossils were derived most likely from formations flanking the southern Appalachians in northern Alabama.

  12. Assessing landslide potential on coastal bluffs near Mukilteo, Washington—Geologic site characterization for hydrologic monitoring

    USGS Publications Warehouse

    Mirus, Benjamin B.; Smith, Joel B.; Benjamin Stark; York Lewis; Abigail Michel; Baum, Rex L.

    2016-01-01

    During the summer 2015, the U.S. Geological Survey collected geologic and geotechnical data for two sites on coastal bluffs along the eastern shore of Puget Sound, Washington. The U.S. Geological Survey also installed hydrologic instrumentation at the sites and collected specimens for laboratory testing. The two sites are located on City of Mukilteo open-space land and are about 0.6 kilometers apart. The bluffs at each site are approximately 42 meters high, and rise steeply from the shoreline with 32–35° slopes. The more northerly of the two sites occupies an active landslide and is mostly unvegetated. The other site is forested, and although stable during the preparation of this report, shows evidence of historical and potential landslide activity. The slopes of the bluffs at both sites are mantled by a thin, nonuniform colluvium underlain by clay-rich glacial deposits and tills of the Whidbey Formation or Double Bluff Drift. Till consisting of sand, gravel, and cobbles caps the bluffs and rests on finer grained glacial deposits of sand, silt, and clay. These types of different glacial deposits are dense, vertically fractured, and generally have low permeability, but field observations indicate that locally the deposits are sufficiently permeable to allow lateral flow of water along fractures and subhorizontal boundaries between deposits of different texture. Laboratory tests indicate that many of the deposits are highly plastic, with low hydraulic conductivity, and moderate shear strength. Steep slopes combined with the strength and hydraulic characteristics of the deposits leave the bluffs prone to slope instability, particularly during the wet season when infiltrating rainfall changes moisture content, pore-water pressure, and effective stress within the hillslope. The instrumentation was designed to primarily observe rainfall variability and hydrologic changes in the subsurface that can affect stability of the bluffs, and also to compare the hydrologic

  13. Conversations with Rep. Ken Calvert. Interview by Frank Sietzen Jr.

    PubMed

    Calvert, Ken

    2005-07-01

    Rep. Calvert, chair of the House aeronautics and space subcommittee of the Science Committee, answers questions related to priorities for space in the current congressional session: the Vision for Space Exploration, development of the Crew Exploration Vehicle (CEV) and other heavy-lift launch vehicles, entrepreneurial alliances in the space transportation industry, the U.S. aerospace industry, space tourism, entrepreneurs and NASA, U.S. aeronautics research, a service mission to the Hubble Space Telescope, and priority military space programs. PMID:16044613

  14. Particle size and X-ray analysis of Feldspar, Calvert, Ball, and Jordan soils

    NASA Technical Reports Server (NTRS)

    Chapman, R. S.

    1977-01-01

    Pipette analysis and X-ray diffraction techniques were employed to characterize the particle size distribution and clay mineral content of the feldspar, calvert, ball, and jordan soils. In general, the ball, calvert, and jordan soils were primarily clay size particles composed of kaolinite and illite whereas the feldspar soil was primarily silt-size particles composed of quartz and feldspar minerals.

  15. 77 FR 34093 - License Renewal for Calvert Cliffs Nuclear Power Plant, LLC's

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ... COMMISSION License Renewal for Calvert Cliffs Nuclear Power Plant, LLC's AGENCY: Nuclear Regulatory... Cliffs Nuclear Power Plant site near Lusby, Maryland. The NRC has prepared an Environmental Assessment... dated September 17, 2010, Calvert Cliffs Nuclear Power Plant, LLC (CCNPP) submitted an application...

  16. Paleotemperatures versus sea level: Oxygen isotope signal from fish bone phosphate of the Miocene Calvert Cliffs, Maryland

    NASA Astrophysics Data System (ADS)

    Barrick, Reese E.; Fischer, Alfred G.; Bohaska, David J.

    1993-12-01

    The use of skeletal oxygen isotopic records for use in paleotemperature reconstruction has been hampered by the lack of independent evidence for ocean water oxygen isotopic composition. The δ18O record from homeothermic cetaceans has provided an independent estimate of ocean δ18O values represented by the Calvert and Choptank formations of Maryland. Fish teeth and bones (especially shark and ray teeth) were also collected from these sediments and provide the basis for paleotemperature estimates for represented time slices of the middle Miocene. Trends in δ18O values of the fish phosphate throughout the Calvert Formation are of opposite polarity to the trends from the cetacean bone phosphate. Paleotemperatures calculated using the cetacean proxies for ocean δ18O values sharpen the already present trend, indicating that ocean temperatures increased during episodes of greater glaciation and decreased during periods of lesser or no glaciation. When using modern average ocean values of 0‰ SMOW in the paleotemperature calculation, however, corrected paleotemperatures for the Choptank Formation do not alter the existing pattern of temperatures.

  17. 77 FR 70431 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on November 15, 2012, Moss Bluff Hub, LLC, (Moss Bluff) filed to revise its Statement of Operating Conditions (SOC)...

  18. 78 FR 41397 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on June 28, 2013, Moss Bluff Hub, LLC (Moss Bluff) filed a revised Statement of Operating Conditions (SOC) pursuant to sections 284.123 and 284.224 of the Commission's regulations, (18 CFR 284.123 and 284.224). Moss...

  19. Remote sensing of erosion along ice-rich permafrost bluffs, Beaufort Sea coast, Alaska

    NASA Astrophysics Data System (ADS)

    Jones, B. M.; Arp, C. D.; Jorgenson, M. T.; Hinkel, K. M.; Wobus, C.; Anderson, R.

    2008-12-01

    Rates of shoreline erosion along Arctic coastlines have traditionally been among the highest in the world. However, recent studies of erosion along the Beaufort Sea coast in Alaska have found that rates are increasing relative to these historically high rates. Using a combination of high-resolution historic and contemporary aerial photography and satellite imagery we have also found an interesting shift in the pattern of erosion along a 60km segment of north facing coastline within the National Petroleum Reserve Alaska. Roughly 30 percent of the study coastline is subject to thermo-mechanical erosional niche formation and block collapse. Mean annual erosion rates for coastline types subject to this type of erosion have increased from 8 m/yr (1955-1979) to nearly 18 m/yr (2002-2007). Ice-poor permafrost bluffs had historically eroded at nearly twice the rate of ice-rich permafrost bluffs, however between 2002 and 2007 these bluff types eroded at nearly identical rates. Further, during the remainder of the 2007 ice-free season nearly 25 m of erosion occurred locally along ice-rich permafrost bluffs. The size of blocks that had collapsed during this time ranged from 6 to 12 m wide. This suggests that some areas potentially experienced 2 to 4 episodes of niche formation, block collapse, and block degradation within a single year. This process of erosion is believed to occur during westerly or northwesterly wind events that elevate sea level, removing slumped materials from the bluff toe, and attacking the base of the bluff creating the niche that leads to block collapse. However, during the 2007 ice-free season, an effective wind event of this sort did not occur.

  20. The Hydrogen Economy as a Technological Bluff

    ERIC Educational Resources Information Center

    Vanderburg, Willem H.

    2006-01-01

    The hydrogen economy is a technological bluff in its implied assurance that, despite the accelerating pace at which we are depleting the remaining half of our fossil fuels, our energy future is secure. Elementary thermodynamic considerations are developed to show that a hydrogen economy is about as feasible as a perpetual motion machine. Hydrogen…

  1. Interactions of bluff-body obstacles with turbulent airflows affecting evaporative fluxes from porous surfaces

    NASA Astrophysics Data System (ADS)

    Haghighi, Erfan; Or, Dani

    2015-11-01

    Bluff-body obstacles interacting with turbulent airflows are common in many natural and engineering applications (from desert pavement and shrubs over natural surfaces to cylindrical elements in compact heat exchangers). Even with obstacles of simple geometry, their interactions within turbulent airflows result in a complex and unsteady flow field that affects surface drag partitioning and transport of scalars from adjacent evaporating surfaces. Observations of spatio-temporal thermal patterns on evaporating porous surfaces adjacent to bluff-body obstacles depict well-defined and persistent zonation of evaporation rates that were used to construct a simple mechanistic model for surface-turbulence interactions. Results from evaporative drying of sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. Experimental and theoretical results show persistent enhancement of evaporative fluxes from bluff-rough surfaces relative to smooth flat surfaces under similar conditions. The enhancement is attributed to formation of vortices that induce a thinner boundary layer over part of the interacting surface footprint. For a practical range of air velocities (0.5-4.0 m/s), low-aspect ratio cylindrical bluff elements placed on evaporating sand surfaces enhanced evaporative mass losses (relative to a flat surface) by up to 300% for high density of elements and high wind velocity, similar to observations reported in the literature. Concepts from drag partitioning were used to generalize the model and upscale predictions to evaporation from surfaces with multiple obstacles for potential applications to natural bluff-rough surfaces.

  2. Geology and paleoecology of the Cottonwood Creek delta in the Eocene Tipton Tongue of the Green River Formation and a mammalian fauna from the Eocene Cathedral Bluffs Tongue of the Wasatch Formation, Southeast Washakie Basin, Wyoming

    SciTech Connect

    Roehler, H.W.; Hanley, J.H.; Honey, J.G.

    1988-01-01

    Nonmarine mollusks are used to interpret paleoenvironments and patterns of sedimentation of a fan delta on the east margin of Eocene Lake Gosiute. The delta is composed of a lens of quartzose sandstone intertongued with oil shale. Delta morphology is illustrated by cross sections and paleogeographic maps. A fossil fauna representing five mammalian orders is described and used to establish the age of parts of the Wasatch and Green River formations. There are three chapters in this bulletin.

  3. 76 FR 12726 - DTE Calvert City, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission DTE Calvert City, LLC; Supplemental Notice that Initial Market- Based Rate...-referenced proceeding of DTE Calvert City, LLC's application for market-based rate authority, with...

  4. 78 FR 4467 - UniStar Nuclear Energy, Combined License Application for Calvert Cliffs Power Plant, Unit 3...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-22

    ... Register notice (FR) 76 FR 81994 (December 29, 2011). 2.0 Request/Action The regulations specified in 10... COMMISSION UniStar Nuclear Energy, Combined License Application for Calvert Cliffs Power Plant, Unit 3, Exemption 1.0 Background UniStar Nuclear Energy (UNE), on behalf of Calvert Cliffs Nuclear Project, LLC...

  5. 77 FR 1748 - Atomic Safety and Licensing Board; Calvert Cliffs 3 Nuclear Project, LLC, and UniStar Nuclear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... Meetings/Hearings, 66 FR 31,719 (June 12, 2001) [hereinafter Meeting Security Guidelines]. All individuals... COMMISSION Atomic Safety and Licensing Board; Calvert Cliffs 3 Nuclear Project, LLC, and UniStar Nuclear... Calvert Cliffs 3 Nuclear Project, L.L.C., and UniStar Nuclear Operating Services, L.L.C. (Applicants)...

  6. 24. Stereo view version of Southeast Light and Mohegan Bluffs ...

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

    24. Stereo view version of Southeast Light and Mohegan Bluffs looking east from a distance, ca. 1890. From a contact print of a glass negative from the Mansfield Collection. - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

  7. 78 FR 21930 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on March 29, 2013, Moss Bluff Hub, LLC filed to revise its Statement of Operating Conditions to modify Sections 3.4.4,...

  8. 76 FR 10581 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Filing Take notice that on February 11, 2011, Moss Bluff Hub, LLC filed to revise its Statement of General Terms and Standard Operating Conditions...

  9. Bluff Body Flow Control Using Plasma Actuators

    NASA Astrophysics Data System (ADS)

    Thomas, Flint

    2005-11-01

    In this study, the use of single dielectric barrier discharge plasma actuators for the control of bluff body flow separation is investigated. In particular, surface mounted plasma actuators are used to reduce both drag and unsteady vortex shedding from circular cylinders in cross-flow. It is demonstrated that the plasma-induced surface blowing gives rise to a local Coanda effect that promotes the maintenance of flow attachment. Large reductions in vortex shedding and drag are demonstrated for Reynolds numbers ˜ 10^410^5. Both steady and unsteady plasma-induced surface blowing is explored. Results are presented from experiments involving both two and four surface mounted actuators.

  10. 75 FR 21372 - Calvert Social Investment Fund, et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Calvert Social Investment Fund, et al.; Notice of Application April 19, 2010. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of an application under section 6(c) of...

  11. 75 FR 31835 - Environmental Impact Statement: Calvert and St. Mary's Counties, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ... Counties, Maryland (Federal Register Vol. 72, No. 203; FR Doc. 07-5190) is being withdrawn and an... Federal Highway Administration Environmental Impact Statement: Calvert and St. Mary's Counties, MD AGENCY... this notice to advise the public that a prior Notice of Intent to prepare an Environmental...

  12. 75 FR 60147 - Calvert Cliffs Nuclear Power Plant, LLC; Independent Spent Fuel Storage Installation; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-29

    ... published in the Federal Register on January 14, 2010 (75 FR 2163). Pursuant to 10 CFR 72.46(b)(2), on... promulgated on August 28, 2007 (72 FR 49139). All documents filed in NRC adjudicatory proceedings, including... COMMISSION Calvert Cliffs Nuclear Power Plant, LLC; Independent Spent Fuel Storage Installation; Notice...

  13. Evaluation of In Situ Combustion for Schrader Bluff

    SciTech Connect

    Sarathi, P.; Strycker, A.; Wang, S.

    1999-03-11

    The focus of this report is on the results related to evaluation of in situ combustion processes applied to Schrader Bluff. Initially, overall screening processes were applied to determine which of the EOR methods, were most appropriate for Schrader Bluff. In situ combustion was among the methods considered potentially favorable and was evaluated further. Laboratory scale tube runs were conducted to determine if the kinetic parameters for the crude oil were favorable. Additional sensitivity studies were conducted to evaluate the recovery potential. Described in this report are the results of the (1) initial screening,(2) experimental tube runs, and (3) simulation sensitivity studies as related to in situ combustion in Schrader Bluff.

  14. Overview from bluff east of facility. Note buildings #35 (left). ...

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

    Overview from bluff east of facility. Note buildings #35 (left). #33 (center), and #31 A (right) VIEW WEST - Department of Energy, Grand Junction Office, 2597 B3/4 Road, Grand Junction, Mesa County, CO

  15. Panoramic view from bluff south of Grand Coulee Dam; this ...

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

    Panoramic view from bluff south of Grand Coulee Dam; this segment of the panorama shows the westernmost extend of Franklin D. Roosevelt Lake and part of Grand Coulee Dam, looking north. - Columbia Basin Project, Grand Coulee, Grant County, WA

  16. Disposal of chemical agents and munitions stored at Pine Bluff Arsenal, Pine Bluff, Arkansas

    SciTech Connect

    Ensminger, J.T.; Hillsman, E.L.; Johnson, R.D.; Morrisey, J.A.; Staub, W.P.; Boston, C.R.; Hunsaker, D.B.; Leibsch, E.; Rickert, L.W.; Tolbert, V.R.; Zimmerman, G.P.

    1991-09-01

    The Pine Bluff Arsenal (PBA) near Pine Bluff, Arkansas, is one of eight continental United States (CONUS) Army installations where lethal unitary chemical agents and munitions are stored and where destruction of agents and munitions is proposed under the Chemical Stockpile Disposal Program (CSDP). The chemical agent inventory at PBA consists of approximately 12%, by weight, of the total US stockpile. The destruction of the stockpile is necessary to eliminate the risk to the public from continued storage and to dispose of obsolete and leaking munitions. In 1988 the US Army issued a Final Programmatic Environmental Impact Statement (FPEIS) for the CSDP that identified on-site disposal of agents and munitions as the environmentally preferred alternative (i.e., the alternative with the least potential to cause significant adverse impacts). The purpose of this report is to examine the proposed implementation of on-site disposal at PBA in light of more recent and more detailed data than those on which the FPEIS is based. New population data were used to compute fatalities using the same computation methods and values for all other parameters as in the FPEIS. Results indicate that all alternatives are indistinguishable when the potential health impacts to the PBA community are considered. However, risks from on-site disposal are in all cases equal to or less than risks from other alternatives. Furthermore, no unique resources with the potential to prevent or delay implementation of on-site disposal at PBA have been identified.

  17. Transient platoon aerodynamics and bluff body flows

    NASA Astrophysics Data System (ADS)

    Tsuei, Lun

    There are two components of this experimental work: transient vehicle platoon aerodynamics and bluff-body flows. The transient aerodynamic effects in a four-vehicle platoon during passing maneuvers and in-line oscillations are investigated. A vehicle model is moved longitudinally parallel to a four-car platoon to simulate passing maneuvers. The drag and side forces experienced by each platoon member are measured using strain gauge balances. The resulting data are presented as dimensionless coefficients. It is shown that each car in the platoon experiences a repulsive side force when the passing vehicle is in the neighborhood of its rear half. The side force reverses its direction and becomes an attractive force when the passing vehicle moves to the neighborhood of its front half. The drag force experienced by each platoon member is increased when the passing vehicle is in its proximity. The effects of the lateral spacing and relative velocity between the platoon and the passing vehicle, as well as the shape of the passing vehicle, are also investigated. Similar trends are observed in simulations of both a vehicle passing a platoon and a platoon overtaking a vehicle. During the in-line oscillation experiments, one of the four platoon members is forced to undergo longitudinal periodic motions. The drag force experienced by each platoon member is determined simultaneously during the oscillations. The effects of the location of the oscillating vehicle, the shape of the vehicles and the displacement and velocity amplitudes of the oscillation are examined. The results from the transient conditions are compared to those from the steady tests in the same setup. In the case of a four-car platoon, the drag variations experienced by the vehicles adjacent to the oscillating vehicle are discussed using a cavity model. It is found that when the oscillating car moves forward and approaches its upstream neighbor, itself and its downstream neighbor experiences an increased drag

  18. Bluff recession rates along the Lake Michigan shoreline in Illinois

    USGS Publications Warehouse

    Jibson, R.W.; Staude, J.-M.

    1992-01-01

    For two time periods, 1872-1937 and 1937-1987, rates of retreat vary from 10 to 75 cm/yr between discrete segments of bluffs (defined by lithology) and between time periods for a given bluff segment. The average retreat rates for the entire area, however, do not vary significantly between the two time periods and are approximately 20-25 cm/yr. The temporally constant regional retreat rates and the regular shape of the local shoreline indicate that a long-term uniform rate of retreat prevails and that local variations in rates balance out through time to produce long-term parallel (in map view) bluff retreat in the area. -from Authors

  19. 40 CFR 81.50 - Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Metropolitan Omaha-Council Bluffs... Designation of Air Quality Control Regions § 81.50 Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region. The Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region...

  20. 40 CFR 81.50 - Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Metropolitan Omaha-Council Bluffs... Designation of Air Quality Control Regions § 81.50 Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region. The Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region...

  1. 40 CFR 81.50 - Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Metropolitan Omaha-Council Bluffs... Designation of Air Quality Control Regions § 81.50 Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region. The Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region...

  2. 40 CFR 81.50 - Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Metropolitan Omaha-Council Bluffs... Designation of Air Quality Control Regions § 81.50 Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region. The Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region...

  3. Gas Turbine Engine Staged Fuel Injection Using Adjacent Bluff Body and Swirler Fuel Injectors

    NASA Technical Reports Server (NTRS)

    Snyder, Timothy S. (Inventor)

    2015-01-01

    A fuel injection array for a gas turbine engine includes a plurality of bluff body injectors and a plurality of swirler injectors. A control operates the plurality of bluff body injectors and swirler injectors such that bluff body injectors are utilized without all of the swirler injectors at least at low power operation. The swirler injectors are utilized at higher power operation.

  4. Anatomy of extremely thin marine sequences landward of a passive-margin hinge zone: Neogene Calvert Cliffs succession, Maryland, U.S.A.

    SciTech Connect

    Kidwell, S.M.

    1997-03-01

    Detailed examination of Neogene strata in cliffs 25--35 m high along the western shore of Chesapeake Bay, Maryland, reveals the complexity of the surviving record of siliciclastic sequences {approximately}150 km inland of the structural hinge zone of the Atlantic passive margin. Previous study of the lower to middle Miocene Calvert (Plum Point Member) and Choptank Formations documented a series of third-order sequences 7--10 m thick in which lowstand deposits are entirely lacking, transgressive tracts comprise a mosaic of condensed bioclastic facies, and regressive (highstand) tracts are present but partially truncated by the next sequence boundary; smaller-scale (fourth-order) cyclic units could not be resolved. Together, these sequences constitute the transgressive and early highstand tracts of a larger (second-order Miocene) composite sequence. The present paper documents stratigraphic relations higher in the Calvert Cliffs succession, including the upper Miocene St. Marys Formation, which represents late highstand marine deposits of the Miocene second-order sequence, and younger Neogene fluvial and tidal-inlet deposits representing incised-valley deposits of the succeeding second-order cycle. The St. Marys Formation consists of a series of tabular units 2--5 m thick, each with an exclusively transgressive array of facies and bounded by stranding surfaces of abrupt shallowing. These units, which are opposite to the flooding-surface-bounded regressive facies arrays of model parasequences, are best characterized as shaved sequences in which only the transgressive tract survives, and are stacked into larger transgressive, highstand, and forced-regression sets.

  5. Monitoring stream bluff erosion using repeat terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Neitzel, G.; Gran, K. B.

    2012-12-01

    Terrestrial laser scanning (TLS) technology provides high-resolution topographic data that can be used to detect geomorphic change in fluvial environments. In this study, we utilize successive terrestrial laser scans to investigate the relationship between peak flow rates and stream bluff erosion in the Amity Creek watershed in Duluth, Minnesota. We also combine TLS scan results with bluff inventories from airborne lidar to estimate the volume of sediment erosion from bluffs in the watershed, which is an important source of fine sediment contributing to the creek's turbidity impairment. We selected nine study bluffs to conduct terrestrial laser scans on after all significant flood events over a two-year time period. The study employs a Faro Focus 3D phase-shift laser to collect data. Post-processing of the TLS-point cloud data sets involves: (1) removal of vegetation and objects other than the erosional surface of interest; (2) decimation of the point cloud in PC Tools and extraction of zmin values to produce a data set manageable in GIS; (3) creation of a bare earth digital elevation model (DEM) for each set of scans using ArcMap; and (4) utilization of Geomorphic Change Detection (GCD) software to generate DEMs of Difference (DODs) from subsequent terrestrial laser scans. Preliminary results from three flooding events indicate significant erosional activity at all field sites. Slumps were observed at two bluffs following spring melt and freeze/thaw cycling. Two major precipitation events in late spring and early summer provided a unique opportunity to observe the impact of extreme high flow events on bluff erosion throughout the watershed using TLS technology. 4.75 inches of intermittent rain over a six-day period in late May 2012 (May 23-28) resulted in slumping at many bluffs and one major failure. The ≥100-year flood that occurred on June 19-20 (7.25 inches), 2012 was powerful enough to induce considerable channel change. Slumps occurred at six study sites

  6. 78 FR 33121 - Staff Requirements-SECY-12-0168-Calvert Cliffs 3 Nuclear Project, LLC & UniStar Nuclear Operating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-03

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Staff Requirements--SECY-12-0168--Calvert Cliffs 3 Nuclear Project, LLC & UniStar Nuclear.... On March 11, 2013, in SRM-12-0168, ``Calvert Cliffs 3 Nuclear Project, LLC & UniStar...

  7. Symptom and illness prevalence with biomarkers health study for Calvert City and Southern Livingston County, Kentucky. Final report

    SciTech Connect

    Hamar, G.B.; McGeehin, M.A.; Phifer, B.L.

    1995-05-01

    The Agency for Toxic Substances and Disease Registry conducted a health study of the area surrounding the Calvert City Industrial Complex (CCIC), an industrial site located in Calvert City, Kentucky. The objective of the study was to assess the current health status of residents living near the CCIC compared with the health status of residents of a similar, `nonexposed` comparison community. A total of 720 randomly selected participants from the Calvert City area and a similar comparison area were administered a standardized symptom and illness prevalence questionnaire, performed pulmonary function test, and provided blood and urine specimens for chemical exposure tests and biomedical tests of subclinical organ dysfunction. In general, target area study participated reported illnesses slightly more often, but symptoms less often, than comparison area study participants. No clear pattern of symptoms or illness was discerned.

  8. Panoramic view from bluff south of Grand Coulee Dam; this ...

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

    Panoramic view from bluff south of Grand Coulee Dam; this segment of the panorama shows the terminus of the concrete-lined feeder canal and entrance to Banks Lake at the head of the Grand Coulee. Note the earthen embankment at the easternmost section of Banks Lake, looking northwest. - Columbia Basin Project, Grand Coulee, Grant County, WA

  9. Overview of the Grand Junction Office from Bluff east of ...

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

    Overview of the Grand Junction Office from Bluff east of facility. Note Buildings #35. #33 and #31A in lower left of photograph. VIEW WEST - Department of Energy, Grand Junction Office, 2597 B3/4 Road, Grand Junction, Mesa County, CO

  10. 2. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W ...

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

    2. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W of Ms. 25 on dirt road 2.5 mi. N of Bull Mtn. Cr. Oblique view of N truss from E end. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  11. 3. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W ...

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

    3. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W of Ms. 25 on dirt road 2.5 mi. N of Bull Mtn. Cr. View from S side of E approach. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  12. 4. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W ...

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

    4. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W of Ms. 25 on dirt road 2.5 mi. N of Bull Mtn. Cr. View from N, wide angle. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  13. 5. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W ...

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

    5. IRONWOOD BLUFFS BRIDGE MISSISSIPPI, ITAWAMBA CO. One mile W of Ms. 25 on dirt road 2.5 mi. N of Bull Mtn. Cr. View of underside from NE shore, showing lower panel point, lateral bracing. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  14. 1. IRONWOOD BLUFFS BRIDGE Tombigbee R. MISSISSIPPI, ITAWAMBA CO. One ...

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

    1. IRONWOOD BLUFFS BRIDGE Tombigbee R. MISSISSIPPI, ITAWAMBA CO. One mile W of Ms. 25 on dirt road 2.5 mi. N of Bull Mtn. Cr. Detail of upper panel point, showing components of members. Sarcone Photography, Columbus, Ms. September 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  15. Panoramic view from bluff south of Grand Coulee Dam; this ...

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

    Panoramic view from bluff south of Grand Coulee Dam; this segment of the panorama shows Crescent Bay Lake (in the foreground), the southern limits of the town of Grand Coulee, and Grand Coulee Dam, looking north. - Columbia Basin Project, Grand Coulee, Grant County, WA

  16. Panoramic view from bluff south of Grand Coulee Dam; this ...

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

    Panoramic view from bluff south of Grand Coulee Dam; this segment of the panorama shows the terminus of the concrete-lined feeder canal and entrance to Banks Lake at the head of the Grand Coulee. The southernmost limits of the town of Grand Coulee are seen in the middle. - Columbia Basin Project, Grand Coulee, Grant County, WA

  17. Long-term benthic monitoring programs near the Morgantown and Calvert Cliffs power plants. Annual report, 1980-1984

    SciTech Connect

    Holland, A.F.; Shaughnessy, A.T.; Hiegel, M.H.; Stroup, C.F.

    1985-07-01

    Macrobenthos and physical/chemical factors known to affect them were monitored near Calvert Cliffs on the mainstem of the Chesapeake Bay (1971-1984). These data, along with data collected near Morgantown on the Potomac River (1980-1984), were used to quantify variation in macrobenthic abundance due to spatial patterns, season, year, and power plant operations. Macrobenthos were persistent within bounds determined by year-to-year variation in salinity and dissolved oxygen. All species responded to anoxia by declines in abundance. Species that prefer high mesohaline salinity increased in abundance at Calvert Cliffs; freshwater and estuarine species increased in abundance at Morgantown.

  18. 76 FR 81994 - UniStar Nuclear Energy; Combined License Application for Calvert Cliffs Nuclear Power Plant, Unit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION UniStar Nuclear Energy; Combined License Application for Calvert Cliffs Nuclear Power Plant, Unit 3; Exemption 1.0 Background: UniStar Nuclear Energy (UNE) submitted to the U.S. Nuclear...

  19. Thermal Modeling of NUHOMS HSM-15 and HSM-1 Storage Modules at Calvert Cliffs Nuclear Power Station ISFSI

    SciTech Connect

    Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.; Cuta, Judith M.; Collins, Brian A.; Siciliano, Edward R.

    2012-10-01

    As part of the Used Fuel Disposition Campaign of the Department of Energy (DOE), visual inspections and temperature measurements were performed on two storage modules in the Calvert Cliffs Nuclear Power Station’s Independent Spent Fuel Storage Installation (ISFSI). Detailed thermal models models were developed to obtain realistic temperature predictions for actual storage systems, in contrast to conservative and bounding design basis calculations.

  20. Panoramic view from bluff south of Grand Coulee Dam; this ...

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

    Panoramic view from bluff south of Grand Coulee Dam; this segment of the panorama shows the western end of Crescent Bay Lake (in the foreground), the western limits of the town of Grand Coulee, part of Grand Coulee's transformer yard (center in the distance), and the concrete-lined feeder canal that extends to Banks Lake, looking northwest. - Columbia Basin Project, Grand Coulee, Grant County, WA

  1. Description of the larva of Argia chelata Calvert, 1902 (Odonata: Coenagrionidae).

    PubMed

    Novelo-Gutiérrez, Rodolfo

    2013-01-01

    The larva of Argia chelata is described and figured. It falls into the group of Argia larvae with a moderately prominent ligula and two palpal seta, but it differs from its closest relatives by having labial palp with 2 setae plus one basal setella; the length of the ligula is 30% of its maximum width; basal tergites (1-5) lacking long, fine setae, mainly on midline; S8-10 mostly dark brown; paraprocts with spiniform setae on basal 0.25 and 0.55 of dorsal and ventral borders, respectively. Larvae were found in 2nd to 4th order shallow streams in cloud forest, crawling among debris, fine sand and mud where the water flow is slow or still, close to the shoreline. The larva is compared with A. lacrimans (Hagen), A. pima Garrison, and A. tonto Calvert, species apparently closely related.  PMID:25113363

  2. Pressurized thermal shock evaluation of the Calvert Cliffs Unit 1 Nuclear Power Plant

    SciTech Connect

    Abbott, L

    1985-09-01

    An evaluation of the risk to the Calvert Cliffs Unit 1 nuclear power plant due to pressurized thermal shock (PTS) has been completed by Oak Ridge National Laboratory (ORNL) with the assistance of several other organizations. This evaluation was part of a Nuclear Regulatory Commission program designed to study the PTS risk to three nuclear plants, the other two plants being Oconee Unit 1 and H.B. Robinson Unit 2. The specific objectives of the program were to (1) provide a best estimate of the frequency of a through-the-wall crack in the pressure vessel at each of the three plants, together with the uncertainty in the estimated frequency and its sensitivity to the variables used in the evaluation; (2) determine the dominant overcooling sequences contributing to the estimated frequency and the associated failures in the plant systems or in operator actions; and (3) evaluate the effectiveness of potential corrective measures.

  3. Laboratory measurements of upwelled radiance and reflectance spectra of Calvert, Ball, Jordan, and Feldspar soil sediments

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Usry, J. W.; Witte, W. G.; Gurganus, E. A.

    1977-01-01

    An effort to investigate the potential of remote sensing for monitoring nonpoint source pollution was conducted. Spectral reflectance characteristics for four types of soil sediments were measured for mixture concentrations between 4 and 173 ppm. For measurements at a spectral resolution of 32 mm, the spectral reflectances of Calvert, Ball, Jordan, and Feldspar soil sediments were distinctly different over the wavelength range from 400 to 980 nm at each concentration tested. At high concentrations, spectral differences between the various sediments could be detected by measurements with a spectral resolution of 160 nm. At a low concentration, only small differences were observed between the various sediments when measurements were made with 160 nm spectral resolution. Radiance levels generally varied in a nonlinear manner with sediment concentration; linearity occurred in special cases, depending on sediment type, concentration range, and wavelength.

  4. Thermal Modeling Studies for Active Storage Modules in the Calvert Cliffs ISFSI

    SciTech Connect

    Adkins, Harold E.; Fort, James A.; Suffield, Sarah R.; Cuta, Judith M.; Collins, Brian A.

    2013-06-14

    Temperature measurements obtained for two storage modules in the Calvert Cliffs Nuclear Power Station’s Independent Spent Fuel Storage Installation (ISFSI) as part of the Used Fuel Disposition Campaign of the Department of Energy (DOE) were used to perform validation and sensitivity studies on detailed computational fluid dynamics (CFD) models of the concrete storage modules, including the dry storage canister within the modules. The storage modules in the Calvert Cliffs Nuclear Power Station’s ISFSI are a site-specific version of the standard NUHOMS® HSM. The two modules inspected each contained a 24P DSC loaded with 24 CE 14x14 spent fuel assemblies. The thermal analysis was performed using the STAR-CCM+ package, and the models developed for the specific ISFSI modules yielded temperature predictions in actual storage conditions for the concrete structure, the DSC and its contents, including preliminary estimates of fuel cladding temperatures for the used nuclear fuel. The results of this work demonstrate that existing CFD modeling tools can be used to obtain reasonable and accurate detailed representations of spent fuel storage systems with realistic decay heat loadings when the model omits specific conservatisms and bounding assumptions normally used in design-basis and safety-basis calculations. This paper presents sensitivity studies on modeling detail (for the storage module and the DSC), boundary conditions, and decay heat load, to evaluate the effect of the modeling approach on predicted temperatures and temperature distributions. Because nearly all degradation mechanisms for materials and structures comprising dry storage and transportation systems are dependent on temperature, accurate characterization of local temperatures and temperature gradients that the various components of these systems will experience over the entire storage period has been identified as a primary requirement for evaluation of very long term storage of used nuclear fuel.

  5. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level. 207.170 Section 207.170 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.170 Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level. (a)...

  6. 75 FR 33799 - Moss Bluff Hub, LLC; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Baseline Filing June 8, 2010. Take notice that on June 1, 2010, Moss Bluff Hub, LLC submitted a baseline filing of its Statement of General...

  7. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level. 207.170 Section 207.170 Navigation and Navigable Waters CORPS OF ENGINEERS..., Moss Bluff, Fla.; pool level. (a) The level of the pool shall normally be maintained at elevation...

  8. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level. 207.170 Section 207.170 Navigation and Navigable Waters CORPS OF ENGINEERS..., Moss Bluff, Fla.; pool level. (a) The level of the pool shall normally be maintained at elevation...

  9. 76 FR 53426 - Moss Bluff Hub, LLC; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moss Bluff Hub, LLC; Notice of Baseline Filing Take notice that on August 17, 2011, Moss Bluff Hub, LLC submitted a revised Statement of Operating Conditions, that governs...

  10. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level. 207.170 Section 207.170 Navigation and Navigable Waters CORPS OF ENGINEERS..., Moss Bluff, Fla.; pool level. (a) The level of the pool shall normally be maintained at elevation...

  11. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level. 207.170 Section 207.170 Navigation and Navigable Waters CORPS OF ENGINEERS..., Moss Bluff, Fla.; pool level. (a) The level of the pool shall normally be maintained at elevation...

  12. 75 FR 65230 - Drawbridge Operation Regulation; Arkansas Waterway, Pine Bluff, AR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ...) entitled Drawbridge Operation Regulation; Arkansas Waterway, Pine Bluff, AR in the Federal Register (75 FR... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Arkansas Waterway, Pine... Railroad Drawbridge across the Arkansas Waterway at Mile 67.4 at Pine Bluff, Arkansas. Vessel...

  13. Combustion heat release effects on asymmetric vortex shedding from bluff bodies

    NASA Astrophysics Data System (ADS)

    Cross, Caleb Nathaniel

    2011-07-01

    reduced the temperature of the recirculating gases further, resulting in large (i.e., near-unity) products-to-reactants density ratios in the near-wake. When the fuel was introduced upstream of the bluff body, the BVK heat release dynamics significantly decreased in amplitude. In this case the fuel was, in all likelihood, fully evaporated and well-mixed with the air prior to burning, resulting in greater amounts of fuel entrainment and subsequent heat release in the near-wake than in the close-coupled fuel injection case. In addition, the heat release was distributed more uniformly across the combustor span, which led to stronger density gradients across the near-wake reaction zone than in close-coupled-fuelled flames due to a lack of reactants entrainment into the recirculation zone. This enhanced the damping of vorticity due to dilatation, which inhibited the formation and shedding of the large-scale, coherent vortices. When the local density gradient was large enough, the BVK instability was completely suppressed. A parallel, linear stability analysis was performed in order to further understand the influence of the near-wake combustion process heat release upon the wake instability characteristics. The results of this analysis indicate that the products-to-reactants density and velocity ratios in the near-wake are the primary parameters controlling the onset of local absolute instability (a necessary condition for the global, BVK instability) in reacting wakes. Upon comparing these results to the measured data, absolute instability was predicted for all operating conditions in which relatively high-amplitude BVK heat release dynamics were observed. This was the case for close-coupled fuel injection at all global equivalence ratios, as well as upstream fuel injection at lean equivalence ratios, due to the low temperature rise across the reacting shear layers in these cases. Only upstream fuel injection at near stoichiometric fuel-air ratios resulted in local products

  14. Secondary sulfate minerals from Alum Cave Bluff: Microscopy and microanalysis

    SciTech Connect

    Lauf, R.J.

    1997-07-01

    Microcrystals of secondary sulfate minerals from Alum Cave Bluff, Great Smoky Mountains National Park, were examined by scanning electron microscopy and identified by X-ray fluorescence (XRF) in the SEM. Among the samples the author discovered three new rare-earth sulfates: coskrenite-(Ce), levinsonite-(Y), and zugshunstite-(Ce). Other minerals illustrated in this report include sulfur, tschermigite, gypsum, epsomite, melanterite, halotrichite, apjohnite, jarosite, slavikite, magnesiocopiapite, and diadochite. Additional specimens whose identification is more tentative include pickeringite, aluminite, basaluminite, and botryogen. Alum Cave is a ``Dana locality`` for apjohnite and potash alum, and is the first documented North American occurrence of slavikite.

  15. Driftwood dropstones in mid-Miocene shallow marine strata (Calvert Cliffs, Maryland Coastal Plain): An erratic lithic pebble des not necessarily a cold paleoclimate make

    NASA Astrophysics Data System (ADS)

    Vogt, P. R.; Parrish, M.

    2009-12-01

    Erratic lithic pebbles recovered from marine sediments are routinely identified as Ice-Rafted Debris (IRD), transported by icebergs, sea ice, or river ice discharged into the sea. We suggest this is not always the transport mechanism--especially when other paleoclimatologic proxies indicate relatively warm climates and extensive forests in the pebble provenance regions. Rivers could transport significant amounts of pebbbles as driftwood dropstones, trapped in the roots of trees and later uprooted in floods and carried out to sea. To illustrate a likely example of Tree-Rafted Detritus (TRD), we analyzed a collection of lithic erratics collected from three beds in eroding (5-10 cm/a) mid-Miocene (Serravalian)shallow marine deposits (upper Calvert Formation,Chesapeake Bay, southern Maryland), which predate the ca. 13.9 Ma global cooling and expansion of the East Antarctic Ice Sheet. The ca. 220 specimens (1-10 cm in diameter) are extremely variable in lithology and degree of roundness. The great majority are evidently of Piedmont provenance and were probably rafted ca. 120 km to the collection site from the paleo-mouth of the Susquehanna River, floated out to sea and carried south by the Miocene Coastal Current. River ice can probably be ruled out as the transport mechanism, given the prevailing warm temperate to subtropical climates. Common carbonized wood fragments (typically 2 x 10 cm in outcrop dimensions) in the same strata containing the erratics support driftwood transport. The lithic erratics may serve as independent tracers for terrestrial vertebrate fossils, transported into the Calvert Sea (Atlantic Ocean) by the 'float and bloat' mechanism.(Allowance has to be made for ca. 20 m/Ma post-middle Miocene source region denudation). However,only 3% of the clasts (mostly quartz diorite gneiss)could be readily related to a specific outcrop--the Port Deposit Gneiss near the modern mouth of the Susquehanna River. We suggest that driftwood transport be considered as

  16. Coastal erosion: Processes, timing and magnitudes at the bluff toe

    USGS Publications Warehouse

    Carter, C.H.; Guy, D.E., Jr.

    1988-01-01

    Five Lake Erie bluffs (one interlaminated clay and silt, three clay-rich diamicts and one shale) were surveyed at about 2-week intervals and after wind storms for up to 5 years. Erosion of the bluff toes along this low-energy coast occurred during northeast wind storms, which produced surges of up to 1 m and surf-zone waves of up to 1.2 m. Wave impact and/or uprush caused quarrying, which removed most of the toe material, and abrasion. There were from 1 to 23 erosion events/sites, with maximum magnitudes of erosion ranging from 12 to 55 cm/event. Timing and magnitude were linked to erodibility, maximum water level, storm surge, storm duration and beach width. A threshold maximum water level and a threshold surge were necessary for erosion. At these thresholds, the beach was submerged and wave energy was directly expended on the toe. Erosion did not take place when there was shorefast ice or when debris slopes shielded the toe from waves. The originally cohesive toe materials are easily eroded when they weather to an essentially noncohesive state. Wave erosion is the crucial erosion process; removal of material from the toe prevents the development of a stable slope. ?? 1988.

  17. Blowoff dynamics of bluff body stabilized turbulent premixed flames

    SciTech Connect

    Chaudhuri, Swetaprovo; Kostka, Stanislav; Renfro, Michael W.; Cetegen, Baki M.

    2010-04-15

    This article concerns the flame dynamics of a bluff body stabilized turbulent premixed flame as it approaches lean blowoff. Time resolved chemiluminescence imaging along with simultaneous particle image velocimetry and OH planar laser-induced fluorescence were utilized in an axisymmetric bluff body stabilized, propane-air flame to determine the sequence of events leading to blowoff and provide a quantitative analysis of the experimental results. It was found that as lean blowoff is approached by reduction of equivalence ratio, flame speed decreases and the flame shape progressively changes from a conical to a columnar shape. For a stably burning conical flame away from blowoff, the flame front envelopes the shear layer vortices. Near blowoff, the columnar flame front and shear layer vortices overlap to induce high local stretch rates that exceed the extinction stretch rates instantaneously and in the mean, resulting in local flame extinction along the shear layers. Following shear layer extinction, fresh reactants can pass through the shear layers to react within the recirculation zone with all other parts of the flame extinguished. This flame kernel within the recirculation zone may survive for a few milliseconds and can reignite the shear layers such that the entire flame is reestablished for a short period. This extinction and reignition event can happen several times before final blowoff which occurs when the flame kernel fails to reignite the shear layers and ultimately leads to total flame extinguishment. (author)

  18. Piezoelectric energy harvesting from transverse galloping of bluff bodies

    NASA Astrophysics Data System (ADS)

    Abdelkefi, A.; Hajj, M. R.; Nayfeh, A. H.

    2013-01-01

    The concept of harvesting energy from transverse galloping oscillations of a bluff body with different cross-section geometries is investigated. The energy is harvested by attaching a piezoelectric transducer to the transverse degree of freedom of the body. The power levels that can be generated from these vibrations and the variations of these levels with the load resistance, cross-section geometry, and freestream velocity are determined. A representative model that accounts for the transverse displacement of the bluff body and harvested voltage is presented. The quasi-steady approximation is used to model the aerodynamic loads. A linear analysis is performed to determine the effects of the electrical load resistance and the cross-section geometry on the onset of galloping, which is due to a Hopf bifurcation. The normal form of this bifurcation is derived to determine the type (supercritical or subcritical) of the instability and to characterize the effects of the linear and nonlinear parameters on the level of harvested power near the bifurcation. The results show that the electrical load resistance and the cross-section geometry affect the onset speed of galloping. The results also show that the maximum levels of harvested power are accompanied with minimum transverse displacement amplitudes for all considered (square, D, and triangular) cross-section geometries, which points to the need for performing a coupled analysis of the system.

  19. Hydrodynamic Mass of Bluff Bodies with a Cavity

    NASA Astrophysics Data System (ADS)

    Elgabaili, Mohamed; Desabrais, Kenneth; Johari, Hamid

    2012-11-01

    Hydrodynamic mass of an object may be used to compute the contribution of unsteady drag resulting from potential flow. Even though the hydrodynamic mass of certain bluff bodies such as cylinder and sphere have been available from analytical considerations for a long time, there are no analytical solutions for a general bluff body with a cavity such as a cup facing the flow or a round parachute canopy. There is, however, an analytical solution for spherical shells of various concavities. The translational hydrodynamic mass of cups having various depth and thickness as well as round parachute canopies during inflation was computed using a finite element solver. The kinetic energy of the potential flow around the body was used to extract the hydrodynamic mass. Results indicate that the hydrodynamic mass of a cup can be decomposed into two components, the hydrodynamic mass of a cylinder whose axis is aligned with the flow and the mass of fluid within the cup cavity. Similarly, the hydrodynamic mass of a parachute canopy during various stages of inflation may be written as the hydrodynamic mass of a disk having the same area as the projected area of the canopy plus the mass of fluid enclosed by the canopy. Sponsored by the US Army Natick RDEC.

  20. Plasma actuators for bluff body flow control

    NASA Astrophysics Data System (ADS)

    Kozlov, Alexey V.

    noise. A tandem cylinder configuration with the plasma actuation on the upstream cylinder is investigated using surface dynamic pressure sensors. As a result of the plasma actuation, the surface pressure fluctuations on the downstream cylinder are reduced by about two times at the free-stream velocity of 40 m/s (ReD = 164,000). In addition, this study presents the results of a parametric experimental investigation aimed at optimizing the body force produced by single dielectric barrier discharge (SDBD) plasma actuators used for aerodynamic flow control. A primary goal of the study is the improvement of actuator authority for flow control applications at higher Reynolds number than previously possible. The study examines the effects of dielectric material and thickness, applied voltage amplitude and frequency, voltage waveform, exposed electrode geometry, covered electrode width and multiple actuator arrays. The metric used to evaluate the performance of the actuator in each case is the measured actuator-induced thrust which is proportional to the total body force. It is demonstrated that actuators constructed with thick dielectric material of low dielectric constant and operated at low frequency AC voltage produce a body force that is an order of magnitude larger than that obtained by the Kapton-based actuators used in many previous plasma flow control studies. These actuators allow operation at much higher applied voltages without the formation of discrete streamers which lead to body force saturation.

  1. Disposal of chemical agents and munitions stored at Pine Bluff Arsenal, Pine Bluff, Arkansas. Final phase 1, Environmental report

    SciTech Connect

    Ensminger, J.T.; Hillsman, E.L.; Johnson, R.D.; Morrisey, J.A.; Staub, W.P.; Boston, C.R.; Hunsaker, D.B.; Leibsch, E.; Rickert, L.W.; Tolbert, V.R.; Zimmerman, G.P.

    1991-09-01

    The Pine Bluff Arsenal (PBA) near Pine Bluff, Arkansas, is one of eight continental United States (CONUS) Army installations where lethal unitary chemical agents and munitions are stored and where destruction of agents and munitions is proposed under the Chemical Stockpile Disposal Program (CSDP). The chemical agent inventory at PBA consists of approximately 12%, by weight, of the total US stockpile. The destruction of the stockpile is necessary to eliminate the risk to the public from continued storage and to dispose of obsolete and leaking munitions. In 1988 the US Army issued a Final Programmatic Environmental Impact Statement (FPEIS) for the CSDP that identified on-site disposal of agents and munitions as the environmentally preferred alternative (i.e., the alternative with the least potential to cause significant adverse impacts). The purpose of this report is to examine the proposed implementation of on-site disposal at PBA in light of more recent and more detailed data than those on which the FPEIS is based. New population data were used to compute fatalities using the same computation methods and values for all other parameters as in the FPEIS. Results indicate that all alternatives are indistinguishable when the potential health impacts to the PBA community are considered. However, risks from on-site disposal are in all cases equal to or less than risks from other alternatives. Furthermore, no unique resources with the potential to prevent or delay implementation of on-site disposal at PBA have been identified.

  2. Combustion heat release effects on asymmetric vortex shedding from bluff bodies

    NASA Astrophysics Data System (ADS)

    Cross, Caleb Nathaniel

    2011-07-01

    reduced the temperature of the recirculating gases further, resulting in large (i.e., near-unity) products-to-reactants density ratios in the near-wake. When the fuel was introduced upstream of the bluff body, the BVK heat release dynamics significantly decreased in amplitude. In this case the fuel was, in all likelihood, fully evaporated and well-mixed with the air prior to burning, resulting in greater amounts of fuel entrainment and subsequent heat release in the near-wake than in the close-coupled fuel injection case. In addition, the heat release was distributed more uniformly across the combustor span, which led to stronger density gradients across the near-wake reaction zone than in close-coupled-fuelled flames due to a lack of reactants entrainment into the recirculation zone. This enhanced the damping of vorticity due to dilatation, which inhibited the formation and shedding of the large-scale, coherent vortices. When the local density gradient was large enough, the BVK instability was completely suppressed. A parallel, linear stability analysis was performed in order to further understand the influence of the near-wake combustion process heat release upon the wake instability characteristics. The results of this analysis indicate that the products-to-reactants density and velocity ratios in the near-wake are the primary parameters controlling the onset of local absolute instability (a necessary condition for the global, BVK instability) in reacting wakes. Upon comparing these results to the measured data, absolute instability was predicted for all operating conditions in which relatively high-amplitude BVK heat release dynamics were observed. This was the case for close-coupled fuel injection at all global equivalence ratios, as well as upstream fuel injection at lean equivalence ratios, due to the low temperature rise across the reacting shear layers in these cases. Only upstream fuel injection at near stoichiometric fuel-air ratios resulted in local products

  3. A study of a bluff-body combustor using laser sheet lighting

    NASA Astrophysics Data System (ADS)

    Roquemore, W. M.; Tankin, R. S.; Chiu, H. H.; Lottes, S. A.

    1986-07-01

    Laser sheet lighting is used to study reacting flows with and without heat release in an axisymmetric, unducted and vertically mounted bluff-body combustor. The fuel, which is seeded with titanium tetrachloride vapor, is ejected from a jet located in the center of the bluff-body. The TiCl4 in the dry fuel reacts spontaneously with the water in the annulus air to form titanium dioxide particles. High speed movies and visual observations of vertically and horizontally located sheets of laser light provided remarkably detailed visualization (via Mie scattering) of the vortex dynamics in the near-wake region of the bluff-body.

  4. A numerical analysis of the unsteady flow past bluff bodies

    NASA Astrophysics Data System (ADS)

    Fernando, M. S. U. K.; Modi, V. J.

    1990-01-01

    The paper describes in detail a relatively sophisticated numerical approach, using the Boundary Element Method in conjunction with the Discrete Vortex Model, to represent the complex unsteady flow field around a bluff body with separating shear layers. Important steps in the numerical analysis of this challenging problem are discussed and a performance evaluation algorithm established. Of considerable importance is the effect of computational parameters such as number of elements representing the geometry, time-step size, location of the nascent vortices, etc., on the accuracy of results and the associated cost. As an example, the method is applied to the analysis of the flow around a stationary Savonius rotor. A detailed parametric study provides fundamental information concerning the starting torque time histories, evolution of the wake, Strouhal number, etc. A comparison with the wind tunnel test data shows remarkable correlation suggesting considerable promise for the approach.

  5. The larvae of Epigomphus jannyae Belle, 1993 and E. tumefactus Calvert, 1903 (Insecta: Odonata: Gomphidae)

    PubMed Central

    Ramírez, Alonso; Delgado, Débora

    2016-01-01

    The taxonomic knowledge about immature stages of the insect order Odonata (dragonflies and damselflies) is rather limited in tropical America. Here, the larvae of Epigomphus jannyae Belle, 1993 and E. tumefactus Calvert, 1903 are described, figured, and compared with other described congeners. E. jannyae larva is characterized by 3rd antennomere 1.6 times longer than its widest part; ligula very poorly developed, with ten short, truncate teeth on middle; apical lobe of labial palp rounded and smooth. Lateral margins on abdominal segments (S5–9) serrated, lateral spines on S6–9 small and divergent; male epiproct with a pair of dorsal tubercles at basal 0.66; tips of cerci and paraprocts strongly divergent. The larva of E. tumefactus is characterized by 3rd antennomere 2.3 times longer than its widest part, ligula with 6–7 truncate teeth, apical lobe of labial palp acute and finely serrate. Lateral margins of S6–9 serrate, lateral spines on S7–9; male epiproct with a pair of dorsal tubercles at basal 0.50. Differences with other species were found in 3rd antennomere, lateral spines of S7–9, and the caudal appendages. Epigomphus larvae inhabit small, shallow creeks (1st order streams) where they live in fine benthic sediments. When mature, the larva leaves the water in shady places, climbing small rocks at the water’s edge and metamorphosing horizontally on flat rocks. These new descriptions bring the total number of Epigomphus species with known larval stages to eight; only 28% of the species in this genus are known as larva.

  6. Extreme rates of riverbank erosion of the high bluff formed by the ice-rich syngenetic permafrost (yedoma), Itkillik River, Northern Alaska

    NASA Astrophysics Data System (ADS)

    Kanevskiy, M. Z.; Shur, Y.; Fortier, D.; Jorgenson, T.; Stephani, E.; Strauss, J.

    2013-12-01

    Riverbank erosion in areas underlain by ice-rich permafrost is strongly affected by the processes of thawing of ground ice, which include (1) thermal erosion, and (2) thermal denudation. Thermal erosion is a process of combined thermal and mechanical action of moving water, which results in simultaneous thawing of frozen soil and its removal by water. Thermal erosion can cause block collapse of eroded banks. Thermal denudation is a process of thawing of frozen soils exposed in the bluff due to solar energy and consequent removal of thawed soils by gravity. Studies of riverbank and coastal erosion revealed that the highest rates of erosion are typical of bluffs composed by yedoma (ice- and organic-rich syngenetically frozen silty deposits). Yedoma deposits can be up to 50 m thick, and they contain huge ice wedges up to 10 m wide. Since 2006, we have studied the process of riverbank erosion of the 35 m high exposure of yedoma along the Itkillik River in northern Alaska. Based on five measurements of the areas occupied by wedge ice in panoramic photographs taken in 2006, 2007, 2011, and 2012, the average wedge-ice volume makes 61% of the entire exposed bluff. The total volumetric ground ice content of the Itkillik yedoma, including wedge, segregated and pore ice, is 85%. We detect three main stages of the riverbank erosion for the study site and other similar sites in the areas of ice-rich permafrost: (1) thermal erosion combined with thermal denudation, (2) thermal denudation, and (3) slope stabilization. The first stage includes formation of thermoerosional niches; development of sub-vertical cracks and block-fall collapse of cornices; and thawing and disintegration of blocks of ground ice and frozen soil in the water. All these processes are accompanied by thermal denudation of the exposed bluff. On August 16, 2007, a big portion of the bluff fell down along the crack sub-parallel to the bluff. As a result, the vertical wall more than 65 m long entirely formed by

  7. Seasonal to Decadal Change of Arctic Coastal Bluffs, Barter Island, Alaska

    NASA Astrophysics Data System (ADS)

    Richmond, B. M.; Gibbs, A.; Erikson, L. H.; Beitch, M. J.

    2015-12-01

    Warming air and sea temperatures in the Arctic are leading to elevated levels of permafrost thaw and longer periods of ice-free conditions during the summer months which can lead to increased coastal exposure to storm surge and wave impacts. Using recently collected time-lapse photography, historical maps and imagery, and DEM's derived from airborne lidar and aerial photography using structure from motion (SfM) algorithms, we document coastal bluff change along a 5 km stretch of coast on Barter Island in NE Alaska during a single summer and over several decades. Time-lapse cameras installed during the summers of 2014 and 2015 on the coastal bluffs are used to create an archive of hourly air temperature and pressure, bluff morphology, and sea conditions allowing us to document individual bluff failure events and conditions at the time of failure. The historical rates of bluff retreat are derived from 1947 T-sheet maps, various periods of satellite imagery, aerial orthophoto mosaics, and more recently acquired lidar and SfM DEM data. Coastal change rates at 50 m transect spacing have been calculated over a seven decade time span. We combine these results with elevation models and bluff geology to estimate overall volume change and sediment contribution to the nearshore. These combined datasets are used to better understand the timing and processes of arctic coastal retreat.

  8. Vortex dynamics and flapping patterns of the inverted flag with a bluff body

    NASA Astrophysics Data System (ADS)

    Kim, Hyeonseong; Kim, Junyoung; Kim, Daegyoum

    2015-11-01

    Flow-induced vibration of flexible structures for energy harvesting has drawn attention recently. The inverted flag whose trailing edge is clamped and leading edge is free to move was known to self-excite in a uniform flow of both water and air. In this study, we investigated the effect of an upstream bluff body, a flat plate, on the dynamics of the downstream inverted flag. Periodic vortical structures created by an upstream bluff body make the dynamics of the inverted flag quite different from those of the inverted flag without the bluff body. We examined the motion of the inverted flag by varying the relative displacement of the inverted flag from the bluff body and their relative size. Our results show that the inverted flag can flap with higher frequency and larger amplitude with the upstream bluff body. We also compared the dynamics of the inverted flag with those of the general flag with the upstream bluff body. In order to better understand the dynamics of the flag, the analysis of the flow patterns using particle image velocimetry was also conducted.

  9. Rates and processes of bluff recession along the Lake Michigan shoreline in Illinois

    USGS Publications Warehouse

    Jibson, R.W.; Odum, J.K.; Staude, J.-M.

    1994-01-01

    Examined bluffs along 30 km of the Lake Michigan shoreline from Wilmette to Waukegan, Illinois, to measure amounts and variation in retreat rates and to determine what factors control rates and processes of retreat. The predominant bluff-retreat process is shallow- to intermediate-depth translational landsliding triggered by heavy rainfall and wave erosion at the base of the bluff; rotational slumping and shallow creep and earth flow also are common. Using historical maps and airphotos, we measured amounts of bluff-top retreat at 300 locations. For two time periods, 1872-1937 and 1937-1987, rates of retreat vary from 10 to 75 cm/yr between discrete segments of bluffs (defined by lithology) and between time periods for a given bluff segment. The average retreat rates for the entire area, however, do not vary significantly between the two time periods and are approximately 20-25 cm/yr. Longterm average and short-term extreme lake levels and precipitation also do not vary significantly between the two periods, and thus local temporal variations in retreat rate cannot be attributed to these factors. Shore protection built to date may have altered the spatial distribution of retreat rates in the area but has had little overall effect on the average regional retreat rates. -from Authors

  10. Processes of coastal bluff erosion in weakly lithified sands, Pacifica, California, USA

    NASA Astrophysics Data System (ADS)

    Collins, Brian D.; Sitar, Nicholas

    2008-05-01

    Coastal bluff erosion and landsliding are currently the major geomorphic processes sculpting much of the marine terrace dominated coastline of northern California. In this study, we identify the spatial and temporal processes responsible for erosion and landsliding in an area of weakly lithified sand coastal bluffs located south of San Francisco, California. Using the results of a five year observational study consisting of site visits, terrestrial lidar scanning, and development of empirical failure indices, we identify the lithologic and process controls that determine the failure mechanism and mode for coastal bluff retreat in this region and present concise descriptions of each process. Bluffs composed of weakly cemented sands (unconfined compressive strength — UCS between 5 and 30 kPa) fail principally due to oversteepening by wave action with maximum slope inclinations on the order of 65 at incipient failure. Periods of significant wave action were identified on the basis of an empirical wave run-up equation, predicting failure when wave run-up exceeds the seasonal average value and the bluff toe elevation. The empirical relationship was verified through recorded observations of failures. Bluffs composed of moderately cemented sands (UCS up to 400 kPa) fail due to precipitation-induced groundwater seepage, which leads to tensile strength reduction and fracture. An empirical rainfall threshold was also developed to predict failure on the basis of a 48-hour cumulative precipitation index but was found to be dependent on a time delay in groundwater seepage in some cases.

  11. Apparatus And Method For Reducing Drag Of A Bluff Body In Ground Effect Using Counter-Rotating Vortex Pairs

    DOEpatents

    Ortega, Jason M.; Salari, Kambiz

    2005-08-09

    An aerodynamic base drag reduction apparatus and method for bluff bodies, such as tractor-trailer trucks, utilizing a pair of lift surfaces extending to lift surface tips and located alongside the bluff body such as on opposing left and right side surfaces. In a flowstream substantially parallel to the longitudinal centerline of the bluff body, the pair of lift surfaces generate a pair of counter-rotating trailing vortices which confluence together in the wake of the bluff body in a direction orthogonal to the flowstream. The confluence draws or otherwise turns the flowstream, such as the flowstream passing over a top surface of the bluff body, in and around behind a trailing end of the bluff body to raise the pressure on a base surface at the trailing end and thereby reduce the aerodynamic base drag.

  12. Apparatus And Method For Reducing Drag Of A Bluff Body In Ground Effect Using Counter-Rotating Vortex Pairs

    DOEpatents

    Ortega, Jason M.; Sabari, Kambiz

    2005-12-27

    An aerodynamic base drag reduction apparatus and method for bluff bodies, such as tractor-trailer trucks, utilizing a pair of lift surfaces extending to lift surface tips and located alongside the bluff body such as on opposing left and right side surfaces. In a flowstream substantially parallel to the longitudinal centerline of the bluff body, the pair of lift surfaces generate a pair of counter-rotating trailing vortices which confluence together in the wake of the bluff body in a direction orthogonal to the flowstream. The confluence draws or otherwise turns the flowstream, such as the flowstream passing over a top surface of the bluff body, in and around behind a trailing end of the bluff body to raise the pressure on a base surface at the trailing end and thereby reduce the aerodynamic base drag.

  13. Late Wisconsinan sub-glacial clastic intrusive sheets along Lake Erie bluffs, at Bradtville, Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Dreimanis, Aleksis; Rappol, Martin

    1997-07-01

    Numerous clastic intrusive sheets, a few decimetres to more than 16 m long, 1-120 cm thick, and extending one to more than 25 m laterally, occur along a 350 m long section of the late Wisconsinan Catfish Creek Drift in the Lake Erie bluffs at Bradtville, southwestern Ontario. Most of them are downglacier-dipping dikes, the largest one terminating in the underlying middle Wisconsinan Tyrconnell Formation. Most dikes strike NNE-SSW, at right angles to the local direction of glacier movement during the deposition of Catfish Creek Drift. The tops of some of them are truncated or displaced downglacier by shearing. The main concentration of clastic intrusive sheets is on the upglacier side of a glaciotectonically folded anticline of Tyrconnell Formation clays and silts underlying the Catfish Creek Drift. The host sediments are Catfish Creek till, gravel, sand and silt, and Tyrconnell Formation silt and clay. Most intrusive sheets, particularly the small to medium ones, consist of massive to crudely laminated sand and silt, intruded from below by a dewatering process. The largest dike reflects in its composition mainly the adjoining or higher-lying host-sediment materials, and its main part was formed by downward infilling, or by gravity flows into an open fracture. The large dike is flanked by small laminated silty sand sheets and several small apophyses, some of them injected downward and sideways, others upward by dewatering. The clastic intrusive sheets were formed under a moving glacier, the Erie lobe, probably both at the beginning and towards the end of the deposition of Catfish Creek till. Their location and position was predetermined by glaciotectonically induced listric planar structures and zones of weakness, mainly tension fractures, that strike transverse to glacier movement and dip downglacier and also by confinement of pore-water in a permeable sediment wedge between the less pervious Tyrconnell Formation and massive Catfish Creek basal till.

  14. Experiments to investigate direct containment heating phenomena with scaled models of the Calvert Cliffs Nuclear Power Plant

    SciTech Connect

    Blanchat, T.K.; Pilch, M.M.; Allen, M.D.

    1997-02-01

    The Surtsey Test Facility is used to perform scaled experiments simulating High Pressure Melt Ejection accidents in a nuclear power plant (NPP). The experiments investigate the effects of direct containment heating (DCH) on the containment load. The results from Zion and Surry experiments can be extrapolated to other Westinghouse plants, but predicted containment loads cannot be generalized to all Combustion Engineering (CE) plants. Five CE plants have melt dispersal flow paths which circumvent the main mitigation of containment compartmentalization in most Westinghouse PWRs. Calvert Cliff-like plant geometries and the impact of codispersed water were addressed as part of the DCH issue resolution. Integral effects tests were performed with a scale model of the Calvert Cliffs NPP inside the Surtsey test vessel. The experiments investigated the effects of codispersal of water, steam, and molten core stimulant materials on DCH loads under prototypic accident conditions and plant configurations. The results indicated that large amounts of coejected water reduced the DCH load by a small amount. Large amounts of debris were dispersed from the cavity to the upper dome (via the annular gap). 22 refs., 84 figs., 30 tabs.

  15. Calvert Cliffs Nuclear Power Plant Life Cycle Management/License Renewal Program: System, structure, and component screening. Final report

    SciTech Connect

    Doroshuk, B.W.; Tilden, B.M.; Hostetler, D.R.; Klein, D.J.; Negin, C.A.

    1994-09-01

    Central to the Life Cycle Management (LCM) Program for the Calvert Cliffs Nuclear Plant is its Integrated Plant Assessment (IPA) process; a comprehensive, systematic evaluation of the effectiveness of age-related degradation management for the plant`s important systems, structures, and components. The first step in this process is the screening of functionally important systems, structures that warrant further evaluation of aging issues. A detailed method and procedures for conducting this screening have been developed and thoroughly tested. The development and application of these procedures at Calvert Cliffs should permit other utilities to avoid implementation problems and avoid substantial front-end development costs. The IPA process is initiated by a screening step that identifies important systems, structures, and components for further evaluation. This report contains the screening methodology, provides procedures for System Level Screening and Component Level Screening, and summarizes results for five systems that represent a wide range of use. These are the Reactor Coolant System, Compressed Air System, Saltwater Cooling System, Electrical 4 Kv Transformers and Buses, and the Reactor Protective System. Examples of component screening are included for the Reactor Coolant System. These screening results show how to determine which equipment`s maintenance programs should be checked for degradation management effectiveness.

  16. Numerical simulation of separated flows past bluff bodies

    NASA Astrophysics Data System (ADS)

    Alexandrou, Andreas Neophytou

    1986-12-01

    The steady two-dimensional flow past bluff bodies is simulated numerically using a hybrid Eulerian-Lagrangian model. The boundary layer effects, such as the location of the separation points and the rate of the generation of vorticity, are determined by a boundary layer solver. This solver uses Prandtl's boundary layer equations transformed by the Falkner-Skan transformation and then solved using a cubic spline approximation and a mean weighted residual technique. The vorticity generated at separation is discretized into elemental point vortices and convected downstream into the wake in a Lagrangian manner. The wake is modeled in a finite Eulerian computational domain using a modified Cloud-in-Cell (CIC) method. The velocity field at each time step is obtained as a solution to the rotationality condition using the finite element method in a cartesian mesh with nine-node elements and biquadratic shape functions. The biquadratic shape functions introduce a higher order interpolation scheme for the distribution of the vorticity at the nodal points than the bilinear (area) interpolation used in the original CIC method. The higher order interpolation as used in the CIC formulation performs better than the bilinear interpolation of the original method. This is demonstrated by the simulation of an isolated Rankine vortex. The ability of the CIC method to simulate the dynamics of vortex structures is also tested for the cases of flow past a flat plate and a circular cylinder.

  17. White Bluffs Pickling Acid Cribs expedited response action proposal

    SciTech Connect

    Not Available

    1993-07-01

    The US Environmental Protection Agency (EPA) and Washington State Department of Ecology (Ecology) recommended in a letter dated March 4, 1992 (Attachment 1) that the US Department of Energy (DOE) prepare an expedited response action (ERA) for the White Bluffs Pickling Acid Cribs Site. The lead regulatory agency for this ERA is the EPA, with Ecology providing support. The goal of this ERA is to reduce the potential of any residual contaminant migration from the cribs to the soil column and groundwater. The cribs are the only waste site within the 100-IU-5 operable unit. Since the operable unit is surrounded by other waste units, tracing the potential groundwater contamination from the 100-IU-5 operable unit for this ERA would not be effective. Groundwater will be investigated with the 100-IU-2 operable unit. This ERA proposal presents the characterization data from the site investigations conducted in November of 1992. This information is evaluated to present the best method for reducing potential of contaminant migration from the disposal unit, ensuring both protection of human health and the environment. The ERA proposal will undergo a public review. EPA and Ecology will issue an Action Agreement Memorandum after comment resolution. This Action Memorandum may authorize implementation of the ERA proposal`s recommended alternative. The ERA may also provide a No Further Action Interim Record of Decision (IROD) of the 100-IU-5 operable unit.

  18. Experimental aerodynamic study of a car-type bluff body

    NASA Astrophysics Data System (ADS)

    Conan, Boris; Anthoine, Jérôme; Planquart, Philippe

    2011-05-01

    The Ahmed body is used as a reference model for fundamental studies of car-type bluff body aerodynamics, in particular focused on the influence of the rear slant angle on the drag coefficient. The objectives of the present work are to obtain reliable drag coefficient comparable to the literature and to explain, based on the nature of the flow, its variation when changing the rear slant angle from 10° to 40°. The drag coefficients measured in both an open and a closed test sections differ by less than 0.5% which proves the reliability and reproducibility of the results. The sensitivity of the drag coefficient to some parameters such as the model roughness or the oncoming boundary layer and the lack of precise information on these parameters in the literature could explain the difference observed with the Ahmed drag coefficient data. The various types of measurement techniques used in the study underline their complementarity. The combination of particle image velocimetry and oil visualization provides a deeper understanding of the flow behaviour around the Ahmed body and a physical interpretation of the drag coefficient evolution.

  19. Influence of the bluff body shear layers on the wake of a square prism in a turbulent flow

    NASA Astrophysics Data System (ADS)

    Lander, D. C.; Letchford, C. W.; Amitay, M.; Kopp, G. A.

    2016-08-01

    Despite a substantial body of literature dealing with the effects of free-stream turbulence (FST) on two-dimensional square prism, there remain some open questions regarding the influence of the bluff body shear layer development in a highly perturbed environment and the resulting impact on bluff body flow characteristics. Accordingly, flows with ambient and enhanced FST were studied at ReD=5.0 ×104 using long-duration time-resolved particle image velocimetry (PIV). The data indicate a narrowing and lengthening of the mean wake and an accompanying rise in base pressure. Using triple decomposition, the underlying dynamics of the wake reveal a streamwise lengthening of the individual von Kármán vortex structures, complementing the increase in mean wake length. Close inspection of the shear layer region, in the presence of FST, indicates a substantial increase in curvature towards the body but no pronounced increase in the growth rate. The loci of maximum turbulent kinetic energy and spanwise vorticity in the shear layer region further reveal that the most pronounced changes occur during the very initial stages follow separation. Inspection of a series of instantaneous PIV fields of Q criterion show that the conventional transition pathway, via the formation and subsequent pairing of the Kelvin-Helmholtz (KH) vortices, is bypassed. The KH vortices are observed to immediately cluster and amalgamate before breaking into smaller random eddies. The bypass transition is followed by shear layer reattachment in some cases. This is considered a primary mechanism responsible for the reported changes in the global flow characteristics and the altered wake dynamics. Furthermore, a quantitative definition of the diffusion length is implemented for the square prism wake and its relationship to the Strouhal number and wake formation length is considered.

  20. Short-Term Bluff Recession Behavior Along Pennsylvania's Great Lakes Coastline, USA

    NASA Astrophysics Data System (ADS)

    Foyle, A. M.; Naber, M. D.; Pluta, M. J.

    2011-12-01

    Coastal bluff retreat is a common problem along the world's unconsolidated coastlines. On the Great Lakes coast of Pennsylvania, Quaternary clay-rich glacial till, paleo-lake plain, and sandy strandplain sequences overlie Devonian bedrock. These Quaternary strata are subject to subaerial and lacustrine erosional processes that cause permanent coastal land loss at spatially variable rates, with the former (runoff, slumping, groundwater focusing, etc) dominating over the latter (wave and current scour, abrasion, etc). Land loss is of concern to environmental agencies because land-use planning should account for spatial and temporal variability in land-loss rates, and because bluff erosion contributes to a temporary degradation in coastal water quality. The goal of this study is to evaluate spatial variability in bluff retreat rates along a 20 km sector of Pennsylvania's short Great Lakes coast. High resolution LiDAR data covering a one-decade time frame (1998-2007) permit bluff-crest mapping on two comparable data sets that captures change within a timeframe similar to CZM planning intervals. Short-term recession data can be more useful, cost-effective, and accurate than long-term analyses that use lower-resolution field measurements, T-sheets, and historical aerial photography. Bluffs along the 20 km coastal study site consist of up to 26 m of unlithified Quaternary sediments overlying a 1-4 m ledge of sub-horizontal Devonian shale and sandstone. Bluff slopes range from 20-90 degrees, beaches are narrow (<8 m wide) or absent, and the bluffs are seasonally shielded by ground-freeze and lake ice. DEMs, hillshades, and slope and contour maps were generated from bare-earth 1998 and 2007 LiDAR data, and checked against 2005 aerial ortho-photography. Maps were analyzed at a scale of 1:120 in ArcGIS and the bluff crest was identified primarily by the visual-break-in-slope method. Rates of bluff retreat derived using DSAS vary from unresolvable to as much as 2.2 m

  1. Twin solution calorimeter determines heats of formation of alloys at high temperatures

    NASA Technical Reports Server (NTRS)

    Darby, J. B., Jr.; Kleb, R.; Kleppa, O. J.

    1968-01-01

    Calvert-type, twin liquid metal solution calorimeter determines the heats of formation of transition metal alloys at high temperatures. The twin differential calorimeter measures the small heat effects generated over extended periods of time, has maximum operating temperature of 1073 degrees K and an automatic data recording system.

  2. 33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration,...

  3. 33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration,...

  4. 33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration,...

  5. 33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration,...

  6. 33 CFR 207.169 - Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation. 207.169 Section 207.169 Navigation... REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration,...

  7. Correlation between heat transfer and fluctuating pressure in the separated region of a bluff body

    NASA Astrophysics Data System (ADS)

    Igarashi, T.

    The paper presents results of a series of experimental studies on heat transfer in the separated region of bluff bodies of various shapes, including a flat plate normal to an airstream, an inclined flat plate, a circular cylinder, and a triangular cylinder. Special attention is given to the correlation between the heat transfer and the rms value of the fluctuating pressure; a new correlation was developed instead of the traditional relation between the average Nusselt number and the Reynolds number. In the new equation, the average heat transfer on the rear face of bluff bodies is correlated with the fluctuating pressure coefficient Cp sub r prime where the constant C ranges from 0.38 and 0.48, depending on the behavior of the shear layer variations for separated regions of bluff bodies.

  8. Real-time monitoring of bluff stability at Woodway, Washington, USA

    USGS Publications Warehouse

    Baum, R.L.; Harp, E.L.; Likos, W.J.; Powers, P.S.; LaHusen, R.G.

    1998-01-01

    On January 15, 1997, a landslide of approximately 100,000-m3 from a coastal bluff swept five cars of a freight train into Puget Sound at Woodway, Washington, USA, 25 km north of downtown Seattle. The landslide resulted from failure of a sequence of dense sands and hard silts of glacial and non-glacial origin, including the Lawton Clay, a hard, jointed clayey silt that rarely fails in natural slopes. Joints controlled ground-water seepage through the silt and break-up of the landslide mass. During September of 1997, the US Geological Survey began measuring rainfall, ground-water pressures, and slope movement at the bluff where the landslide occurred. Data are collected every 15 minutes and updated hourly on the World-Wide-Web. Pore pressures observed from September 1997 to February 1998 generally were low and pressures near the bluff face, in the upper few meters of the hard clayey silt, increased gradually.

  9. DNS of turbulent flow past a bluff body with a compliant tensegrity surface

    NASA Astrophysics Data System (ADS)

    Karandikar, Anish; Bewley, Thomas

    2007-11-01

    Direct numerical simulation (DNS) is used to study turbulent incompressible flow past a bluff body with a compliant surface. We use a 3D time-dependent coordinate transformation to account for the motion of the bluff body surface. Spatially, the flow domain is discretized using a dealiased pseudospectral method in the axial and azimuthal directions, while the radial (wall-normal) direction is discretized using a finite difference scheme. The grid is stretched in the azimuthal direction, which is handled spectrally. This leads to a unique challenge when solving the Poisson equation in the fractional step method for the time march, which we address with both multigrid and preconditioned BiCGStab algorithms. We are presently extending this flow code with a model for the compliant bluff body surface based on the ``tensegrity fabric'' paradigm which combines compressive members (bars) and tensile members (tendons) in a stable, flexible network.

  10. Study of motion of flexible eel from the wake of bluff body in a cross flow

    NASA Astrophysics Data System (ADS)

    Sin, Vai Kuong; Deng, Wen Yue; Xiao, Wei Hang

    2012-09-01

    In this research, interaction between eel and vortex shedding behind a bluff body is studied numerically, aiming to optimize the oscillation of eels by coupling with the altering vertices. Effects of different factors such as length of eel, width of bluff body and flow speed on vibration of eels are also aimed to be investigated. A 2-dimensional Fluid-Structure Interaction Model that simulates the motion of eel under vortex shedding behind a bluff body is constructed by using the computational fluid dynamics (CFD) software - COMSOL Multiphysics. Simulations based on laminar flow regime are performed and the results show that undulating motion of the eel is successfully modeled with the Fluid-Structure Interaction Model along with Arbitrary Lagrangian-Eulerian (ALE) method.

  11. Sedimentological indicators of paleoenvironments and siliciclastic stratigraphic sequences in some Miocene deposits of the Calvert Cliffs, southern Maryland

    USGS Publications Warehouse

    Shideler, G.L.

    1994-01-01

    Middle Miocene siliciclastic deposits comprising the Calvert Cliffs section at the Baltimore Gas and Electric Company's (BG&E) nuclear power plant site in southern Maryland were analyzed in terms of lithostratigraphy, sedimentary structures, and granulometric parameters, to interprete paleo-environments within a sequence-stratigraphic framework. In terms of sequence-stratigraphic models, the BG&E section can be interpreted as consisting of two genetic stratigraphic sequences (Galloway model), namely, a shelf sequence and an overlying deltaic sequence. Using the Exxon model, the section consists of two third-order (1-5 m.y. duration) depositional sequences. The stratigraphic sequences of the BG&E section reflect both relatively short-term eustatic transgressive events, as well as a long-term regressive trend with associated local deltation and coastal progradation. The regression probably signified a regional basinward shift of depocenters within the Salisbury embayment during Miocene time. -from Author

  12. National Assessment of Historical Shoreline Change: A Pilot Study of Historical Coastal Bluff Retreat in the Great Lakes, Erie, Pennsylvania

    USGS Publications Warehouse

    Hapke, Cheryl J.; Malone, Shamus; Kratzmann, Meredith

    2009-01-01

    Coastal bluff retreat is a chronic problem along many high-relief coastlines in the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regard-ing trends and rates of bluff retreat. There is also a need for a comprehensive analysis that is consistent from one coastal region to another. To address these national needs, the U.S. Geological Survey (USGS), as part of the National Assessment of Coastal Change Hazards Project, conducted a pilot study of bluff retreat along the Lake Erie, Pa., coastline to assess the feasibility of undertaking a larger, multi-state analysis in the Great Lakes region. This report provides an overview of the pilot-study location and bluff geomorphology, the data sources and methodology, results of the analysis, and a discussion of the feasibility of undertaking a similar analysis along eroding bluffs in other Great Lakes states. This pilot study is part of an ongoing effort by the USGS to provide a comprehensive analysis of historical shoreline change and cliff and bluff retreat along open-ocean coastlines of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of the work is to develop standard, repeatable methods for mapping and analyzing coastal change so that systematic and consistent periodic updates of coastal erosion can be made nationally. Bluff-retreat evaluations are conducted by comparing the location of a historical bluff edge digitized from aerial photographs with those of recent bluff edges interpreted from both aerial photographs and lidar topographic surveys. The historical bluff edge is from 1938, whereas the more recent bluff edges are from 1998 and 2006 lidar data. Long-term (68-year) rates of retreat are calculated using the available bluff-edge data. The rates of retreat presented in this report represent conditions from the 1930s to 1998/2006, and are not intended for

  13. Reinvestigation of the Bee Bluff Structure South of Uvalde, Texas, `The Uvalde Crater.'

    NASA Astrophysics Data System (ADS)

    Graham, R. A.; Wilson, W. F.

    2005-03-01

    Investigation of the Bee Bluff Structure provides new evidence for an impact crater origin. A 300 kg rock preserving numerous impactite features called the 'Uvalde Crater Rosetta Stone,' promises to provide detail on the first billion nanoseconds of the impact events.

  14. Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi

    USGS Publications Warehouse

    Cobban, W.A.; Kennedy, W.J.

    1995-01-01

    The Prairie Bluff Chalk of Alabama and Mississippi yields a diverse ammonite fauna of Maastrichtian age. Twenty-eight species, of which three are new, are recorded. The bulk of the fauna can be referred to a Discoscaphites conradi assemblage zone, but some elements in the fauna are significantly older. -Authors

  15. Distributed forcing of the flow past a blunt-based axisymmetric bluff body

    NASA Astrophysics Data System (ADS)

    Jardin, Thierry; Bury, Yannick; DAEP Team

    2012-11-01

    The topology of bluff body wakes may be highly sensitive to forcing at frequencies close to intrinsic flow instabilities. In a similar way, a steady but spatially varying forcing at wavelengths close to specific flow instabilities can lead to analogous outcomes. Such forcing is commonly referred to as distributed forcing. However, although distributed forcing has proven to be a relevant control strategy for three-dimensional flows past nominally two-dimensional geometries (e.g. extruded circular cylinder at Re > 180), its impact on the flow past nominally three-dimensional geometries is still unknown. Here we assess the receptivity of the flow past a blunt-based axisymmetric bluff body to an azimuthally distributed forcing applied at the periphery of the bluff-body base. We show that the impact of RSPa, RSPb and RSPc instabilities on the drag fluctuations experienced by the bluff body can be suppressed, depending on the forcing wavelengths. The authors acknowledge the French Ministry of Defence and DGA for funding this work.

  16. Drag reduction on a bluff body at yaw angles to 30 degrees

    NASA Technical Reports Server (NTRS)

    Howard, Floyd G.; Goodman, Wesley L.

    1987-01-01

    The base separation alleviation and drag reduction effectiveness of transverse rectangular grooves and longitudinal v-grooves in the afterbody shoulder region of a bluff body is investigated for body yaw angles of 0-30 deg. The grooves are found to be beneficial in reducing both freestream and axial drag coefficients at yaw angles of up to 25 deg.

  17. Review of thermal-hydraulic calculations for Calvert Cliffs and H. B. Robinson PTS study. [Pressurized thermal shock

    SciTech Connect

    Jo, J.H.; Yuelys-Miksis, C.; Rohatgi, U.S.

    1984-01-01

    Thermal-hydraulic transient calculations performed by LANL using the TRAC-PF1 code and by INEL using the RELAP5 code for the USNRC pressurized thermal shock (PTS) study of the Calvert Cliffs and H.B. Robinson Nuclear Power Plants have been reviewed at BNL including the input decks and steady state calculations. Furthermore, six transients for each plant have been selected for the in-depth review. Simple hand calculations based on the mass and energy balances of the entire reactor system, have been performed to predict the temperature and pressure of the reactor system, and the results have been compared with those obtained by the code calculation. In general, the temperatures and pressures of the primary system calculated by the codes have been very reasonable. The secondary pressures calculated by TRAC appear to indicate that the codes have some difficulty with the condensation model and further work is needed to assess the code calculation of the U-tube steam generator pressure when the cold auxiliary feedwater is introduced to the steam generator. However, it is not expected that this uncertainty would affect the transient calculations significantly.

  18. Orientation of bluff body for designing efficient energy harvesters from vortex-induced vibrations

    NASA Astrophysics Data System (ADS)

    Dai, H. L.; Abdelkefi, A.; Yang, Y.; Wang, L.

    2016-02-01

    The characteristics and performances of four distinct vortex-induced vibrations (VIVs) piezoelectric energy harvesters are experimentally investigated and compared. The difference between these VIV energy harvesters is the installation of the cylindrical bluff body at the tip of cantilever beam with different orientations (bottom, top, horizontal, and vertical). Experiments show that the synchronization regions of the bottom, top, and horizontal configurations are almost the same at low wind speeds (around 1.5 m/s). The vertical configuration has the highest wind speed for synchronization (around 3.5 m/s) with the largest harvested power, which is explained by its highest natural frequency and the smallest coupled damping. The results lead to the conclusion that to design efficient VIV energy harvesters, the bluff body should be aligned with the beam for low wind speeds (<2 m/s) and perpendicular to the beam at high wind speeds (>2 m/s).

  19. Aerodynamic drag reduction apparatus for gap-divided bluff bodies such as tractor-trailers

    DOEpatents

    Ortega, Jason M.; Salari, Kambiz

    2006-07-11

    An apparatus for reducing the aerodynamic drag of a bluff-bodied vehicle such as a tractor-trailer in a flowstream, the bluff-bodied vehicle of a type having a leading portion, a trailing portion connected to the leading portion, and a gap between the leading and trailing portions defining a recirculation zone. The apparatus is preferably a baffle assembly, such as a vertical panel, adapted to span a width of the gap between the leading and trailing portions so as to impede cross-flow through the gap, with the span of the baffle assembly automatically adjusting for variations in the gap width when the leading and trailing portions pivot relative to each other.

  20. Large eddy simulation of flows after a bluff body: Coherent structures and mixing properties

    NASA Astrophysics Data System (ADS)

    Zhang, Pei; Han, Chao; Chen, Yiliang

    2013-10-01

    This paper performs large eddy simulations (LES) to investigate coherent structures in the flows after the Sydney bluff-body burner, a circular bluff body with an orifice at its center. The simulations are validated by comparison to existing experimental data. The Q function method is used to visualize the instantaneous vortex structures. Three kinds of structures are found, a cylindrical shell structure in the outer shear layer, a ring structure and some hairpin-like structures in the inner shear layer. An eduction scheme is employed to investigate the coherent structures in this flow. Some large streaks constituted by counter-rotating vortices are found in the outer shear layer and some well-organized strong structures are found in the inner shear layer. Finally, the influences of coherent structures on scalar mixing are studied and it is shown that scalar in the recirculation region is transported outward by coherent structures.

  1. Modeling erosion of ice-rich permafrost bluffs along the Alaskan Beaufort Sea coast

    NASA Astrophysics Data System (ADS)

    Barnhart, Katherine R.; Anderson, Robert S.; Overeem, Irina; Wobus, Cameron; Clow, Gary D.; Urban, Frank E.

    2014-05-01

    The Arctic climate is changing, inducing accelerating retreat of ice-rich permafrost coastal bluffs. Along Alaska's Beaufort Sea coast, erosion rates have increased roughly threefold from 6.8 to 19 m yr-1 since 1955 while the sea ice-free season has increased roughly twofold from 45 to 100 days since 1979. We develop a numerical model of bluff retreat to assess the relative roles of the length of sea ice-free season, sea level, water temperature, nearshore wavefield, and permafrost temperature in controlling erosion rates in this setting. The model captures the processes of erosion observed in short-term monitoring experiments along the Beaufort Sea coast, including evolution of melt notches, topple of ice wedge-bounded blocks, and degradation of these blocks. Model results agree with time-lapse imagery of bluff evolution and time series of ocean-based instrumentation. Erosion is highly episodic with 40% of erosion is accomplished during less than 5% of the sea ice-free season. Among the formulations of the submarine erosion rate we assessed, we advocate those that employ both water temperature and nearshore wavefield. As high water levels are a prerequisite for erosion, any future changes that increase the frequency with which water levels exceed the base of the bluffs will increase rates of coastal erosion. The certain increases in sea level and potential changes in storminess will both contribute to this effect. As water temperature also influences erosion rates, any further expansion of the sea ice-free season into the midsummer period of greatest insolation is likely to result in an additional increase in coastal retreat rates.

  2. Transition to bluff body dynamics in the wake of vertical axis turbines

    NASA Astrophysics Data System (ADS)

    Araya, Daniel; Dabiri, John

    2015-11-01

    A unifying characteristic among bluff bodies is a similar wake structure independent of the shape of the body. We present experimental data to demonstrate that the wake of a vertical axis wind/water turbine (VAWT) shares similar features to that of a bluff body, namely a circular cylinder. For a fixed Reynolds number (Re ~ 104) and variable tip-speed ratio, 2D particle image velocimetry (PIV) is used to measure the velocity field in the wake of three different laboratory-scale turbines: a 2-bladed, 3-bladed, and 5-bladed VAWT, each with similar geometry. From the PIV measurements, the time-averaged and dynamic characteristics of the wake are evaluated. In all cases, we observe three distinct regions in the VAWT wake: (1) the near wake, where periodic blade shedding dominates; (2) a transition region, where blade vortices decay and growth of a shear layer instability occurs; (3) the far wake, where bluff body wake oscillations dominate. We further characterize this wake transition with regard to turbine solidity and examine its relation to the mean flow, an important metric for power production within a wind farm.

  3. Symmetry breaking in 3D wake of a bluff body generates rotation and drift

    NASA Astrophysics Data System (ADS)

    Lacis, Ugis; Brosse, Nicolas; Bagheri, Shervin; Lundell, Fredrik; Mazzino, Andrea; Olivieri, Stefano; Kellay, Hamid

    2014-11-01

    Bluff body wakes have historically been important for understanding nature and aiding industry. For Reynolds numbers above approximately Re ~ 10 , a recirculation bubble develops behind the bluff body. If a solid or elastic appendage is attached to the bluff body, it may exert a torque and a side force on the body. Previously we have used theory, numerical simulations and experiments to investigate and explain this phenomenon in two dimensions. Now we advance our investigation to three dimensional objects. More specifically, we consider a sphere and attach a sheet of given shape behind it for Re = 200 . We investigate the problem using numerical simulations and extend our theoretical model developed in two dimensions. Then we complement our findings with water tank experiments of freely falling cylinder with sheet of various mass behind it. We show that the torque and side force can be greatly changed if the density of the sheet is different compared to the cylinder. Finally we discuss the possibility of optimal configurations for propulsion generation.

  4. Hydrodynamic and chemical effects of hydrogen dilution on soot evolution in turbulent nonpremixed bluff body ethylene flames

    NASA Astrophysics Data System (ADS)

    Deng, Sili; Mueller, Michael E.; Chan, Qing N.; Qamar, Nader H.; Dally, Bassam B.; Alwahabi, Zeyad T.; Nathan, Graham J.

    2015-11-01

    A turbulent nonpremixed bluff body ethylene/hydrogen (volume ratio 2:1) flame is studied and compared with the ethylene counterpart [Mueller et al., Combust. Flame, 160, 2013]. Similar to the ethylene buff body flame, a low-strain recirculation zone, a high-strain neck region, and a downstream jet-like region are observed. However, the maximum soot volume fraction in the recirculation zone of the hydrogen diluted case is significantly lower than the ethylene case. Large Eddy Simulation is used to further investigate soot evolution in the recirculation zone and to elucidate the role of hydrogen dilution. Since the central jet Reynolds numbers in both cases are the same (approximately 30,900), the jet velocity of the hydrogen diluted case is higher, resulting in a shorter and leaner recirculation zone. In addition, hydrogen dilution chemically suppresses soot formation due to the reduction of C/H ratio. Consequently, the reduction of the soot volume fraction for the hydrogen diluted ethylene flame is attributed to two major effects: hydrodynamic and chemical effects.

  5. Drag and lift reduction of a 3D bluff-body using active vortex generators

    NASA Astrophysics Data System (ADS)

    Aider, Jean-Luc; Beaudoin, Jean-François; Wesfreid, José Eduardo

    2010-05-01

    In this study, a passive flow control experiment on a 3D bluff-body using vortex generators (VGs) is presented. The bluff-body is a modified Ahmed body (Ahmed in J Fluids Eng 105:429-434 1983) with a curved rear part, instead of a slanted one, so that the location of the flow separation is no longer forced by the geometry. The influence of a line of non-conventional trapezoïdal VGs on the aerodynamic forces (drag and lift) induced on the bluff-body is investigated. The high sensitivity to many geometric (angle between the trapezoïdal element and the wall, spanwise spacing between the VGs, longitudinal location on the curved surface) and physical (freestream velocity) parameters is clearly demonstrated. The maximum drag reduction is -12%, while the maximum global lift reduction can reach more than -60%, with a strong dependency on the freestream velocity. For some configurations, the lift on the rear axle of the model can be inverted (-104%). It is also shown that the VGs are still efficient even downstream of the natural separation line. Finally, a dynamic parameter is chosen and a new set-up with motorized vortex generators is proposed. Thanks to this active device. The optimal configurations depending on two parameters are found more easily, and a significant drag and lift reduction (up to -14% drag reduction) can be reached for different freestream velocities. These results are then analyzed through wall pressure and velocity measurements in the near-wake of the bluff-body with and without control. It appears that the largest drag and lift reduction is clearly associated to a strong increase of the size of the recirculation bubble over the rear slant. Investigation of the velocity field in a cross-section downstream the model reveals that, in the same time, the intensity of the longitudinal trailing vortices is strongly reduced, suggesting that the drag reduction is due to the breakdown of the balance between the separation bubble and the longitudinal vortices

  6. Environmental radionuclide concentrations in the vicinity of the Calvert Cliffs Nuclear Power Plant and the Peach Bottom Atomic Power station: 1995

    SciTech Connect

    Jones, T.S.; Frithsen, J.B.; McLean, R.I.

    1997-02-01

    The Maryland Power Plant Research Program monitors concentrations of natural, weapons, and power plant produced radionuclides in environmental samples collected from the Chesapeake Bay in the vicinity of the Calvert Cliffs Nuclear Power Plant (CCNPP) and from the Susquehanna River-Chesapeake Bay system in the vicinity of Peach Bottom Atomic Power Station (PBAPS). The purpose of this monitoring is to determine the fate, transport, and potential effects of power plant produced radionuclides. Radionuclide concentrations in shellfish, finfish, aquatic vegetation, and sediment were measured using high-resolution gamma spectrometry. Radionuclides in environmental samples originated from natural sources, atmospheric weapons testing, and normal operations of CCNPP and PBAPS.

  7. Decade-scale coastal bluff retreat from LiDAR data: Lake Erie coast of Pennsylvania, USA

    NASA Astrophysics Data System (ADS)

    Foyle, A. M.; Naber, M. D.

    2010-12-01

    Bluff retreat is a significant problem along many parts of the southern Great Lakes coastline of the United States. On the Pennsylvania coast of Lake Erie, where semi-consolidated clay-rich glacial till sequences overlie bedrock, erosion of the bluffs results in a permanent loss of fine-grained sediment from the coastal zone. Bluff retreat is of concern to coastal property owners and regulators because evaluating landslide hazards and developing regulations on coastal development must account for spatial and temporal variability in coastal retreat. Bluff retreat also contributes to temporary degradation in coastal water quality. The goal of this pilot study is to evaluate medium-term spatial variability in bluff retreat magnitudes and rates along a sector of the Pennsylvania coast. Newly available high resolution LiDAR data cover a one-decade time frame (1998-2007) and permit mapping of the bluff-crest position on two comparable, high-quality data sets. In contrast, long-term coastal change analyses typically involve comparison of a recent LiDAR data set with an older, lower-resolution data set developed from either field measurements, T-sheets, or aerial photography. While the older data can have much larger inherent errors than the LiDAR data, they become less significant over the longer time frames involved. The 6 km, geologically homogeneous, coastal bluff site is characterized by ~20 m of unlithified Pleistocene glacial tills and lake plain sediments overlying a 3-4 m ledge of near-horizontal Devonian shale and sandstone bedrock. Bluff slopes range from 35-90 degrees, beaches are narrow to non-existent, and the coast is frequently protected by ground-freeze and a lake ice shelf during winter. DEMs, hillshades, and slope and contour maps were generated from the bare-earth 1998 and 2007 LiDAR data, and checked against 2005 aerial ortho-photography. Maps were analyzed at a scale of 1:120 in ArcGIS and the bluff crest was identified primarily by the visual

  8. Guide to Surficial Geology and River-Bluff Exposures, Noatak National Preserve, Northwestern Alaska

    USGS Publications Warehouse

    Hamilton, Thomas D.

    2009-01-01

    From its origin in rugged granitic highlands of the central Brooks Range, the Noatak River flows westward between the De Long Mountains and the Baird Mountains before turning south to enter Kotzebue Sound. Glaciers of middle and late Pleistocene age entered the Noatak River valley from the east, north, and south. Glaciers flowed down the upper Noatak River valley from the rugged peaks at its head, merging with tributary glaciers that issued from cirque-headed valleys along its south flank. Farther downvalley, small glaciers flowed northward from the Baird Mountains and much larger glaciers issued from the De Long Mountains. The De Long Mountains glaciers expanded southward to cover parts of the Noatak valley floor; they dammed the Noatak River during successive advances, creating a series of glacial lakes. The more extensive glacial advances dammed huge lakes that filled the Aniuk Lowland to overflowing. At various times, overflow waters spilled northward through Howard Pass, southward via Hunt River into the Kobuk River system, and westward down a series of channelways that skirted south of the glacier margins. Prominent bluffs along the Noatak River and its principal tributaries reveal glacial, glaciolacustrine, fluvial, and eolian sediments. More than 120 measured bluff exposures are described and illustrated in this report. These are dated by 92 radiocarbon age determinations and by the presence of the old Crow tephra, which was deposited about 130,000-140,000 years ago. Six geologic base maps, which cover sections of the Noatak River valley from east to west, show the locations of the river bluffs in relation to the glacial, glaciolacustrine, and fluvial deposits that cover the valley floor. The upper Noatak River valley is dominated by a bulky end moraine near Douglas Creek that was deposited during the last glacial maximum about 25,000-15,000 14C yr BP (termed the Itkillik II phase in the central Brooks Range glacial succession). Bluffs along this section of

  9. Reduction of Aerodynamic Noise Generated by a Bluff-Shaped Pantograph Head Using Synthetic Jet Actuators

    NASA Astrophysics Data System (ADS)

    Kishige, Hiroaki; Minobe, Takayuki; Ikeda, Mitsuru; Suzuki, Masahiro

    With an increase in the maximum speed of Shinkansen trains, it becomes imperative to resolve aerodynamic and aeroacoustic problems related to pantographs. Hence, some methods based on flow control have been studied to improve the aerodynamic and aeroacoustic characteristics. In this study, the authors attempted to control the flow around a pantograph by using synthetic jets. The results of numerical and experimental tests indicate that the synthetic jets can stabilize the flow around the bluff-shaped pantograph head, thus resulting in a reduction in aerodynamic noise.

  10. Dry-surface coating method for visualization of separation on a bluff body

    NASA Technical Reports Server (NTRS)

    Sadeh, W. Z.; Brauer, H. J.; Durgin, J. R.

    1981-01-01

    A simple and relatively accurate dry-surface coating method for visualization of the flow separation on a circular cylinder (or any bluff body) during wind tunnel tests is described. The technique consists of (1) application of a thin coating composed of an indicator and a paint carrier; (2) drying of the film; (3) conditioning of the coating with an acidic solution to ensure a suitable color reaction; (4) release into the body wake of a gas able to produce a base through chemical reaction with the solvent of the conditioning solution; and (5) color reaction according to pH.

  11. 230. CCC Camp NP21 was established at the Bluffs (Doughton ...

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

    230. CCC Camp NP-21 was established at the Bluffs (Doughton Park) located on what is now the Doughton Park Maintenance Area. It opened September 1, 1938 and was abandoned July 17, 1942. Crews were assigned to the first landscape development on the parkway in the Cumberland Knob Area. This work entailed removal of debris and downed wood, slope flattening and rounding, seeding shoulders and planting along the road, and improvement of fields and forest to the side of the roadway. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  12. Revised age for the Gosses Bluff impact structure, Northern Territory, Australia, based on Ar-40Ar-39 dating

    NASA Astrophysics Data System (ADS)

    Milton, Daniel J.; Sutter, John F.

    1987-09-01

    Ar-40Ar-39 dating of a pumiceous suevite clast from the melt breccia at Gosses Bluff consisting largely of extremely fine-grained sanidine yields a discordant age spectrum, probably reflecting some diffusional loss of argon. High-temperature increments that together yield a near-plateau age of 142.5 Ma are apparently not affected by argon loss and offer the best estimate of the date of the Gosses Bluff event. The event may fall in the latest Jurassic Period, but more likely falls in the earliest Cretaceous, probably in one of the reverse-polarity magnetochrons M16, M17, or M18.

  13. The flame anchoring mechanism and associated flow structure in bluff-body stabilized lean premixed flames

    NASA Astrophysics Data System (ADS)

    Michaels, Dan; Shanbhogue, Santosh; Ghoniem, Ahmed

    2015-11-01

    We present numerical analysis of a lean premixed flame anchoring on a heat conducting bluff-body. Different mixtures of CH4/H2/air are analyzed in order to systematically vary the burning velocity, adiabatic flame temperature and extinction strain rate. The study was motivated by our experimental measurements in a step combustor which showed that both the recirculation zone length and stability map under acoustically coupled conditions for different fuels and thermodynamic conditions collapse using the extinction strain rate. The model fully resolves unsteady two-dimensional flow with detailed chemistry and species transport, and without artificial flame anchoring boundary conditions. The model includes a low Mach number operator-split projection algorithm, coupled with a block-structured adaptive mesh refinement and an immersed boundary method for the solid body. Calculations reveal that the recirculation zone length correlates with the flame extinction strain rate, consistent with the experimental evidence. It is found that in the vicinity of the bluff body the flame is highly stretched and its leading edge location is controlled by the reactants combustion characteristics under high strain. Moreover, the flame surface location relative to the shear layer influences the vorticity thus impacting the velocity field and the recirculation zone. The study sheds light on the experimentally observed collapse of the combustor dynamics using the reactants extinction strain rate.

  14. Characteristics of suspended sediment in the San Juan River near Bluff, Utah

    USGS Publications Warehouse

    Thompson, K.R.; Mundorff, J.C.

    1982-01-01

    Fluvial-sediment data were collected for the San Juan River near Bluff beginning in 1914 and terminating in 1980. A double-mass curve showed a change in relationship between annual suspended-sediment discharge and annual stream discharge between the water years 1941-44 and 73. Possible causes for these changes in laboratory procedures, and unusually large runoff that occurred in 1941 and 1972. An unknown or unidentified factor may also be involved. The actual reason for this change in relationship may never be fully understood. Navajo Dam apparently has had no significant effect on fluvial sediment at the sampling site. Mean annual suspended sediment discharge in the San Juan River near Bluff was about 25,410,000 tons ranging from 3,234,000 tons in 1978 to 112,400,000 tons in 1941. The use of annual stream discharge to predict annual suspended-sediment discharge at the site will produce poor results because of size and diversity of the basin and the quality of records available. A positive correlation exists between sand concentration and stream discharge at this site, however, considerable variability is evident. This relationship does not exist when stream discharge exceeds 6,000 cubic feet per second. It is recommended that if collection of suspended-sediment records be resumed in this reach of the river an alternative sampling site should be selected and the use of pumping samplers considered because of the remoteness of the area. (USGS)

  15. Simulation, Modeling and Feedback Control of the flow around a Square-Back Bluff Body

    NASA Astrophysics Data System (ADS)

    Dalla Longa, Laurent; Morgans, Aimee; Imperial College London-Flow Control Team

    2015-11-01

    Because of capacity, aesthetic and comfort requirements, most road vehicles are not streamlined but blunt bluff bodies. The flow exhibits a large wake recirculation area leading to high pressure drag, which at highway speeds, represents the main source of energy loss. In this work, Large Eddy Simulations of the flow past a square-back bluff body with interacting shear layers are performed with the aim of reducing aerodynamic drag. A linear feedback control strategy is applied to increase the back face pressure and therefore obtain drag reduction. Synthetic jets located along the perimeter of the back face are used for actuation while body mounted sensors record the base pressure. System identification, via harmonic actuator forcing, is used to characterize the flow response to actuation, which is assumed to be dynamically linear. Based on the identified frequency response, a feedback controller is designed in the frequency domain which aims to either attenuate or amplify base pressure fluctuations by shaping of the sensitivity transfer function. This is first done for a D-shaped body. Current work extends this strategy to a simplified lorry geometry on which experiments were carried out recently.

  16. Fluctuating wind forces measured on a bluff body extending from a cavity

    NASA Astrophysics Data System (ADS)

    King, Brian W.

    1989-12-01

    The effect of wind forces measured on a bluff body extending from a cavity was investigated. This was accomplished by measuring wind induced vibratory inputs to a plexiglas bluff body model. The model extended from a ground board cavity installed in the AFIT 5-Foot Wind Tunnel. Forces and moments were measured from an 8 element load cell unit built and installed in the base of a plexiglas model. Three different size cavity openings were tested for both a no-rotation and 45 degree rotation referenced to the wind. Data was taken at individual speed points between 55 ft/s and 180 ft/s, producing Reynolds number based on model width in the range of 1.5 x 10 to the 5th power to 5.0 x 10 to the 5th power. Baseline data for a closed cavity configuration was collected and compared to previous studies conducted at the USAF Academy. Force and moment coefficient data are presented, comparing cavity opening and model rotation effects. Results of shedding frequency analysis are presented based on transient data recorded.

  17. Power production locality of bluff body flutter mills using fully coupled 2D direct numerical simulation

    NASA Astrophysics Data System (ADS)

    Kuhl, J. M.; Desjardin, P. E.

    2012-01-01

    Two-dimensional, fully coupled direct numerical simulations (DNS) are conducted to examine the local energy dynamics of a flexible cantilevered plate in the wake of a two-dimensional circular cylinder. The motion of the cantilevered plate is described using a finite element formulation and a fully compressible, finite volume Navier Stokes solver is used to compute the flow field. A sharp interface level set method is employed in conjunction with a ghost fluid method to describe the immersed boundaries of the bluff body and flexible plate. DNS is first conducted to validate the numerical methodology and compared with previous studies of flexible cantilevered plates and flow over bluff bodies; excellent agreement with previous results is observed. A newly defined power production/loss geometry metric is introduced based on surface curvature and plate velocity. The metric is found to be useful for determining which sections of the plate will produce energy based on curvature and deflection rate. Scatter plots and probability measures are presented showing a high correlation between the direction of energy transfer (i.e., to or from the plate) and the sign of the newly defined curvature-deflection-rate metric. The findings from this study suggest that a simple local geometry/kinematic based metric can be devised to aid in the development and design of flexible wind energy harvesting flutter mills.

  18. Bluff-body stabilized flame dynamics of lean premixed syngas combustion

    NASA Astrophysics Data System (ADS)

    Im, Hong G.; Kim, Yu Jeong; Lee, Bok Jik; Kaust Team

    2015-11-01

    Recently, syngas combustion has been actively investigated for the potential application to integrated gasification combined cycle (IGCC) systems. While lean premixed combustion is attractive for both reduced emission and enhanced efficiency, flame instability becomes often an issue. Bluff-bodies have been adopted as effective flame holders for practical application of premixed flames. In the present study, high-fidelity direct numerical simulations are conducted to investigate the dynamics of lean premixed syngas flames stabilized on a bluff-body, in particular at the near blow-off regime of the flame. A two-dimensional domain of 4 mm height and 20 mm length with a flame holder of a 1 mm-by-1 mm square geometry is used. For a syngas mixture with the equivalence ratio of 0.5 and the CO:H2 ratio of 1, several distinct flame modes are identified as the inflow velocity approaches to the blowoff limit. The sequences of extinction pathway and combustion characteristics are discussed.

  19. Wind sheltering of a lake by a tree canopy or bluff topography

    NASA Astrophysics Data System (ADS)

    Markfort, Corey D.; Perez, Angel L. S.; Thill, James W.; Jaster, Dane A.; Porté-Agel, Fernando; Stefan, Heinz G.

    2010-03-01

    A model is developed to quantify the wind sheltering of a lake by a tree canopy or a bluff. The experiment-based model predicts the wind-sheltering coefficient a priori, without calibration, and is useful for one-dimensional (1-D) lake hydrodynamic and water quality modeling. The model is derived from velocity measurements in a boundary layer wind tunnel, by investigating mean velocity profiles and surface shear stress development downwind of two canopies and a bluff. The wind tunnel experiments are validated with field measurements over an ice-covered lake. Both wind tunnel and field experiments show that reduced surface shear stress extends approximately 50 canopy heights downwind from the transition. The reduction in total shear force on the water surface is parameterized by a wind-sheltering coefficient that is related to the reduction of wind-affected lake area. While all measurements are made on solid surfaces, the wind-sheltering coefficient is shown to be applicable to the lake surface. Although several canopy characteristics, such as its height, aerodynamic roughness, and its porosity affect the transition of velocity profiles and surface shear stress onto a lake, a relationship based on canopy height alone provides a sufficiently realistic estimate of the wind-sheltering coefficient. The results compare well with wind-sheltering coefficients estimated by calibration of lake water temperature profile simulations for eight lakes.

  20. The molluscan fauna of the Alum Bluff group of Florida, Part II, Astartacea, Carditacea, Chamacea

    USGS Publications Warehouse

    Gardner, Julia

    1926-01-01

    The first of the series of papers upon the Mollusca of the Alum Bluff group covered the orders of the Prionodesmacea and the Anomalodesmacea. The Mollusca were by the beginning of Miocene time so far advances in development that the great majority are included under the highest of the three orders, the Teleodesmacea, characterized in the adult stages by the differentiation of the hinge teeth into distinct cardinals and laterals. This paper, the second of the series, covers the most primitive of the Teleodesmacea in the Alum Bluff group. All three of the superfamilies considered - the Astartacea, the Carditaeea, and the Chamacea-are included under Dall's group of the Diogenodonta, which is characterized in the normal forms by one or two laterals and not more than three cardinals. The Carditacea are very closely related to the Astartacea in hinge armature but differ in the development of a pronounced radial sculpture. The Chamacea have until recently been considered an offshooting group from the Carditacea that have been greatly modified by their sessile habit. Some doubt has been thrown upon this relationship by the late morphologic studies of Odhner.

  1. The Dietary guideline 2005 and physical activities role in weight management of University Arkansas at Pine Bluff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To evaluate the effectiveness of the weight loss initiative, researchers at the University of Arkansas at Pine Bluff conducted an obesity prevention intervention based on the Dietary Guidelines for Americans approach. A 12 month study was conducted that focused on interventions to improve physical ...

  2. The Illinois Natural Heritage Conservation Education Kit V. [Ecology and Management of Special Habitats: Dune, Cave, Cliff, Bluff, and Urban.

    ERIC Educational Resources Information Center

    Stone, Sally F.

    The ecology and management of special habitats is the theme of this instructional guide. It contains 24 activities designed to help teachers familiarize their students with dune, cave, cliff, bluff, and urban habitats in Illinois. Each activity (which is ready to be copied and given to students) includes an objective (called a mission) and…

  3. Numerical aerodynamic analysis of bluff bodies at a high Reynolds number with three-dimensional CFD modeling

    NASA Astrophysics Data System (ADS)

    Bai, YuGuang; Yang, Kai; Sun, DongKe; Zhang, YuGuang; Kennedy, David; Williams, Fred; Gao, XiaoWei

    2013-02-01

    This paper focuses on numerical simulations of bluff body aerodynamics with three-dimensional CFD (computational fluid dynamics) modeling, where a computational scheme for fluid-structure interactions is implemented. The choice of an appropriate turbulence model for the computational modeling of bluff body aerodynamics using both two-dimensional and three-dimensional CFD numerical simulations is also considered. An efficient mesh control method which employs the mesh deformation technique is proposed to achieve better simulation results. Several long-span deck sections are chosen as examples which were stationary and pitching at a high Reynolds number. With the proposed CFD method and turbulence models, the force coefficients and flutter derivatives thus obtained are compared with the experimental measurement results and computed values completely from commercial software. Finally, a discussion on the effects of oscillation amplitude on the flutter instability of a bluff body is carried out with extended numerical simulations. These numerical analysis results demonstrate that the proposed three-dimensional CFD method, with proper turbulence modeling, has good accuracy and significant benefits for aerodynamic analysis and computational FSI studies of bluff bodies.

  4. Flow-induced noise control behind bluff bodies with various leading edges using the surface perturbation technique

    NASA Astrophysics Data System (ADS)

    Lu, Z. B.; Halim, D.; Cheng, L.

    2016-05-01

    The present paper is devoted to an investigation on the flow-induced noise control downstream of bluff bodies with various leading edges using the surface perturbation technique. Four typical leading edges used in various engineering applications were studied in this work: the semi-circular, square, 30° symmetric trapezoid and 30° asymmetric trapezoid leading edges. The surface perturbation was created by piezo-ceramic actuators embedded underneath the surface of a bluff body placed in a cross flow. To suppress the flow-induced noise downstream bluff bodies with those leading edges, the surface perturbation technique was implemented. Based on the experiments, a noise reduction in the duct of more than 14.0 dB has been achieved for all leading-edge cases. These results indicated that the vortex shedding and its flow-induced noise have been successfully suppressed by the proposed control scheme. The flow structure alteration around the bluff bodies and the shear layer shift phenomenon observed on the trailing edges were then investigated for interpreting the control mechanism for this flow-induced noise suppression, which were based on the vortex shedding strength suppression and vortex shedding frequency shift phenomenon. The effective control position for various leading edges was also studied for developing optimal control strategies for practical engineering applications.

  5. The effect of splitter plate on fluid flow and heat transfer characteristics past various bluff-body configurations

    NASA Astrophysics Data System (ADS)

    Soumya, Sunakraneni; Prakash, K. Arul

    2015-11-01

    Numerical simulation of five different bluff body configurations with splitter plate is carried out to analyse the fluid flow and heat transfer characteristics for Reynolds number (Re) ranging from 50-200. The governing equations are discretized using SUPG - finite element method. The bluff body configurations considered are elliptic cylinder of axis ratios (AR =0.5-1.0), square cylinder, rhombus of axis ratios (AR =0.5-1.0), equilateral triangle, and semi-circular cylinder. The splitter plate length varied from L =0.0Dh-6.0Dh,(Dh = Bluff body hydraulic diameter). It is observed that interaction of separated shear layers from top and bottom surfaces of the body is inhibited and vortex shedding is suppressed for certain combinations of bluff body configuration, Re and splitter plate length and wake region is modified significantly. Reduction in drag approximately of the order 2% to 50% is attained and overall heat transfer (Q) is increased due to splitter plate.

  6. Environmental radionuclide concentrations in the vicinity of the Calvert Cliffs Nuclear Power Plant and the Peach Bottom Atomic Power Station: 1996--1997. Final report

    SciTech Connect

    McLean, R.I.; Jones, T.S.

    1998-11-20

    The Maryland Power Plant Research Program monitors concentrations of natural, weapons, and power plant produced radionuclides in environmental samples collected from the Chesapeake Bay in the vicinity of the Calvert Cliffs Nuclear Power Plant (CCNPP) and from the Susquehanna River-Chesapeake Bay system in the vicinity of Peach Bottom Atomic Power Station (PBAPS). The purpose of this monitoring is to determine the fate, transport, and potential effects of power plant-produced radionuclides. This report contains a description of monitoring activities and data collected during the 1996 and 1997 calendar years. Radionuclide concentrations in shellfish, finfish, aquatic vegetation, and sediment were measured using high-resolution gamma spectrometry. Radionuclides in environmental samples originated from natural sources, historic atmospheric weapons testing, and normal operations of CCNPP and PBAPS.

  7. Wavelet-based adaptive numerical simulation of unsteady 3D flow around a bluff body

    NASA Astrophysics Data System (ADS)

    de Stefano, Giuliano; Vasilyev, Oleg

    2012-11-01

    The unsteady three-dimensional flow past a two-dimensional bluff body is numerically simulated using a wavelet-based method. The body is modeled by exploiting the Brinkman volume-penalization method, which results in modifying the governing equations with the addition of an appropriate forcing term inside the spatial region occupied by the obstacle. The volume-penalized incompressible Navier-Stokes equations are numerically solved by means of the adaptive wavelet collocation method, where the non-uniform spatial grid is dynamically adapted to the flow evolution. The combined approach is successfully applied to the simulation of vortex shedding flow behind a stationary prism with square cross-section. The computation is conducted at transitional Reynolds numbers, where fundamental unstable three-dimensional vortical structures exist, by well-predicting the unsteady forces arising from fluid-structure interaction.

  8. A dry-surface coating method for visualization of separation. [bluff bodies

    NASA Technical Reports Server (NTRS)

    Sadeh, W. Z.; Brauer, H. J.; Durgin, J. R.

    1980-01-01

    A relatively simple and reasonably accurate dry-surface coating method for visualization of the separation line on a bluff body was devised and successfully tested. This technique is based on the color reaction of a dry film containing a pH indicator with an appropriate gas released in the body wake. The dry-surface coating method is effective at any Reynolds number and for both incident laminar and turbulent flows. It further supplies a colorful permanent of consistently good photographic quality of the separation line. The effectiveness and accuracy of this technique were tested in visualizing the separation angle on a circular cylinder in both laminar and turbulent crossflows at subcritical Reynolds numbers. Separation angles revealed by the visualization were within + or - 4 percent of their counterparts deduced from the mean wall pressure distribution.

  9. High-Speed Linear Raman Spectroscopy for Instability Analysis of a Bluff Body Flame

    NASA Technical Reports Server (NTRS)

    Kojima, Jun; Fischer, David

    2013-01-01

    We report a high-speed laser diagnostics technique based on point-wise linear Raman spectroscopy for measuring the frequency content of a CH4-air premixed flame stabilized behind a circular bluff body. The technique, which primarily employs a Nd:YLF pulsed laser and a fast image-intensified CCD camera, successfully measures the time evolution of scalar parameters (N2, O2, CH4, and H2O) in the vortex-induced flame instability at a data rate of 1 kHz. Oscillation of the V-shaped flame front is quantified through frequency analysis of the combustion species data and their correlations. This technique promises to be a useful diagnostics tool for combustion instability studies.

  10. Geometrical Scaling of an Ablative Bluff Body under Different Outer Flow Velocity and Temperature Configurations

    NASA Astrophysics Data System (ADS)

    Allard, Michael; White, Christopher M.; Dubief, Yves

    2015-11-01

    Experimental results investigating the geometrical scaling and local properties of an eroding low temperature ablator (para-dichlorobenzene) are presented. The bluff body is placed in a heated open-circuit wind tunnel and the effects of incoming outer flow velocity (uniform and spatially varying) and temperature on the ablation process are investigated. Image sequencing of the projected area in the streamwise-spanwise and streamwise-wall normal flow direction are used to quantify the time evolution of the geometrical shape and compute local recession rates and curvature. The geometrical self-similarity and local recession rates are evaluated and compared to Moore et al. and Huang et al. who investigated erosion under the action of fluid shear force and dissolution, respectively. This work is supported by the NSF (CBET-0967224).

  11. A comparison of dispersion calculations in bluff body wakes using LES and unsteady RANS

    SciTech Connect

    Paschkewitz, J S

    2006-01-19

    Accurate modeling of the dispersion behavior of sprays or particles is critical for a variety of problems including combustion, urban pollution or release events, and splash and spray transport around heavy vehicles. Bluff body wakes are particularly challenging since these flows are both highly separated and strongly unsteady. Attempting to model the dispersion of droplets or particles interacting with bluff body wakes is even more difficult since small differences in the flow field encountered by particles can lead to large differences in the dispersion behavior. Particles with finite inertia can exhibit additional complicating effects such as preferential concentration. In this preliminary study, we consider the dispersion of solid particles in the wake of a rectangular plane at a Reynolds number (Re) of 10000 and that of droplets in the wake of a simplified tractor-trailer geometry at Re = 2 x 10{sup 6} using both the Large Eddy Simulation (LES) and Unsteady Reynolds-Averaged Navier-Stokes (URANS) turbulence modeling approaches. The calculations were performed using identical meshes for both the LES and URANS models. Particle stresses are not backcoupled to the carrier fluid velocity solution. In the case of the rectangular plane wake, the LES calculation predicts a finer-scale and more persistent wake structure than the URANS one; the resulting particle dispersion is considerably ({approx} 40%) underpredicted for low inertia particles. For the case of the simplified tractor-trailer geometry, although the LES is underresolved, similar trends are observed with strong differences in the vertical and horizontal dispersion of the smallest particles. These results suggest that it may be necessary to use LES to accurately capture the dispersion behavior of small, low inertia particles or droplets, but that URANS may be sufficient for problems in which only large particles with substantial inertia are of primary concern.

  12. Modeling flow around bluff bodies and predicting urban dispersion using large eddy simulation.

    PubMed

    Tseng, Yu-Heng; Meneveau, Charles; Parlange, Marc B

    2006-04-15

    Modeling air pollutant transport and dispersion in urban environments is especially challenging due to complex ground topography. In this study, we describe a large eddy simulation (LES) tool including a new dynamic subgrid closure and boundary treatment to model urban dispersion problems. The numerical model is developed, validated, and extended to a realistic urban layout. In such applications fairly coarse grids must be used in which each building can be represented using relatively few grid-points only. By carrying out LES of flow around a square cylinder and of flow over surface-mounted cubes, the coarsest resolution required to resolve the bluff body's cross section while still producing meaningful results is established. Specifically, we perform grid refinement studies showing that at least 6-8 grid points across the bluff body are required for reasonable results. The performance of several subgrid models is also compared. Although effects of the subgrid models on the mean flow are found to be small, dynamic Lagrangian models give a physically more realistic subgrid-scale (SGS) viscosity field. When scale-dependence is taken into consideration, these models lead to more realistic resolved fluctuating velocities and spectra. These results set the minimum grid resolution and subgrid model requirements needed to apply LES in simulations of neutral atmospheric boundary layer flow and scalar transport over a realistic urban geometry. The results also illustrate the advantages of LES over traditional modeling approaches, particularly its ability to take into account the complex boundary details and the unsteady nature of atmospheric boundary layer flow. Thus LES can be used to evaluate probabilities of extreme events (such as probabilities of exceeding threshold pollutant concentrations). Some comments about computer resources required for LES are also included. PMID:16683605

  13. Experimental and Numerical Investigation of Flow Structures around Cylindrical Bluff Bodies

    NASA Astrophysics Data System (ADS)

    Yagmur, Sercan; Dogan, Sercan; Aksoy, Muharrem H.; Canli, Eyub; Ozgoren, Muammer

    2015-05-01

    The understanding and quantitative prediction of velocity and pressure fluctuations in turbulent flows around such bluff bodies have been evolving over the years. The main aim of the present work is to investigate experimentally and numerically the flow field in the wake region of different bluff bodies such as circular, square and triangle cross section cylinders placed horizontally perpendicular to the uniform flow. The experimental studies were performed by Particle Image Velocimetry (PIV) method in an open water channel at Reynolds numbers 5000 and 10000 defined according to the characteristic lengths of the cylinders in the facilities of Selcuk University of Advanced Technology Research and Application Center in Turkey. The experimental results are compared to the numerical results obtained by means of transient simulation with LES turbulence model of ANSYS-Fluent Software. It is shown that the numerical and experimental results have a good agreement in respect of the instantaneous and time-averaged flow field patterns of vorticity, velocity component streamwise direction and streamline topology. In addition, drag coefficient of the geometries were also numerically calculated. For all geometries the wake length in x and y directions and size of the foci of the streamlines are decreasing by increasing Reynolds numbers in time-averaged results. The time-averaged flow patterns of both experimental and numerical results have considerable symmetry with respect to the centerline of each cylinder. Contours of the time-averaged stream wise velocity for Re=10000 demonstrate that the stagnation point around the symmetry plane moves further upstream for all cylinders in accordance with Re=5000. The maximum drag coefficient value was yielded for the square cross-section cylinder as 1.78 due to the sharp-edged geometry.

  14. Response dynamics of bluff-body stabilized conical premixed turbulent flames with spatial mixture gradients

    SciTech Connect

    Chaudhuri, Swetaprovo; Cetegen, Baki M.

    2009-03-15

    Response of bluff-body stabilized conical turbulent premixed flames was experimentally studied for a range of excitation frequencies (10-400 Hz), mean flow velocities (5, 10 and 15 m/s) and three different spatial mixture distributions (uniform, inner and outer enrichment). Upstream excitation was provided by a loudspeaker producing velocity oscillation amplitudes of about 8% of the mean flow velocity. Flame response was detected by a photomultiplier observing the CH{sup *} emission from the flame. The studied turbulent flames exhibited transfer function characteristics of a low-pass filter with a cutoff Strouhal number between 0.08 and 0.12. The amplification factors at low frequencies ranged from 2 to 20 and generally increased for mean flow velocities from 5 to 15 m/s. The highest levels of amplification were found for the outer mixture enrichment followed in decreasing order by uniform and inner mixture gradient cases. The high levels of flame response for the outer enrichment case were attributed to the enhanced flame-vortex interaction in outer jet shear layer. At high excitation levels (u{sup '}/U{sub m}{approx}0.3) for U{sub m}=5 m/ s where non-linear flame response is expected, the flame exhibited a reduced amplitude response in the frequency range between 40 and 100 Hz for the uniform and outer equivalence ratio gradient cases and no discernible effect for the inner equivalence ratio gradient. In all cases, transfer function phase was found to vary linearly with excitation frequency. Finally, a relationship between the amplitude characteristics of the bluff-body wake transfer function and flame blowoff equivalence ratio was presented. (author)

  15. Long-term benthic monitoring programs near the Morgantown and Calvert Cliffs power plants - annual report for the first year's studies. Volume III: appendices A-E. Report for Jul 80-Jun 81

    SciTech Connect

    Holland, A.F.; Hiegel, M.H.; Fisher, K.; Hoffman, H.; Johnson, G.F.

    1982-04-01

    This volume contains the following appendices: summary of physical/chemical and sediment data collected between July 1980 and June 1981; Summaries of benthic community data for Calvert Cliffs and Morgantown long-term benthic studies; Summary of biomass data collected between July and December 1980; Summary of size-class distribution data collected for numerically dominant bivalves; and Summary of results of stepwise regression analysis.

  16. Terrestrial LIDAR investigation of the December 2003 and January 2007 activations of the Northridge Bluff landslide, Daly City, California

    USGS Publications Warehouse

    Collins, Brian D.; Kayen, Robert; Reiss, Thomas; Sitar, Nicholas

    2007-01-01

    On December 20, 2003 and again on January 1, 2007, landslides occurred along the coastal bluff that forms the west boundary of Daly City, California sending debris as far as 290 meters downhill and 90 meters into the ocean. This area is known for large landslide events where 150-meter tall coastal bluffs extend southward along the west boundary of San Francisco and San Mateo Counties (Fig. 1). The 2003 and 2007 landslide events occurred west of Northridge Drive in Daly City and just south of Avalon Canyon, which bisects the bluffs in this area (Fig. 2). Residential development, utility lines and roads occupy the land immediately east of this location. As part of a comprehensive project to investigate the failure mechanisms of coastal bluff landslides in weakly lithified sediments along the west coast of the United States, members of the U.S. Geologic Survey (USGS) Coastal and Marine Geology (CMG) Program performed reconnaissance mapping of these landslide events including collection of high-resolution topographic data using CMG's terrestrial LIDAR laser scanning system. This report provides a brief background on each landslide event and presents topographic datasets collected following each event. Downloadable contour data, images, and FGDC-compliant metadata of the surfaces generated from the LIDAR data are also provided. LIDAR data collection and processing techniques used to generate the datasets are outlined. Geometric and volumetric measurements are also presented along with high-resolution cross-sections through various areas of the slide masses and discussion concerning the slides present (2007) configuration is provided.

  17. Theoretical analysis and experimental verification on valve-less piezoelectric pump with hemisphere-segment bluff-body

    NASA Astrophysics Data System (ADS)

    Ji, Jing; Zhang, Jianhui; Xia, Qixiao; Wang, Shouyin; Huang, Jun; Zhao, Chunsheng

    2014-05-01

    Existing researches on no-moving part valves in valve-less piezoelectric pumps mainly concentrate on pipeline valves and chamber bottom valves, which leads to the complex structure and manufacturing process of pump channel and chamber bottom. Furthermore, position fixed valves with respect to the inlet and outlet also makes the adjustability and controllability of flow rate worse. In order to overcome these shortcomings, this paper puts forward a novel implantable structure of valve-less piezoelectric pump with hemisphere-segments in the pump chamber. Based on the theory of flow around bluff-body, the flow resistance on the spherical and round surface of hemisphere-segment is different when fluid flows through, and the macroscopic flow resistance differences thus formed are also different. A novel valve-less piezoelectric pump with hemisphere-segment bluff-body (HSBB) is presented and designed. HSBB is the no-moving part valve. By the method of volume and momentum comparison, the stress on the bluff-body in the pump chamber is analyzed. The essential reason of unidirectional fluid pumping is expounded, and the flow rate formula is obtained. To verify the theory, a prototype is produced. By using the prototype, experimental research on the relationship between flow rate, pressure difference, voltage, and frequency has been carried out, which proves the correctness of the above theory. This prototype has six hemisphere-segments in the chamber filled with water, and the effective diameter of the piezoelectric bimorph is 30mm. The experiment result shows that the flow rate can reach 0.50 mL/s at the frequency of 6 Hz and the voltage of 110 V. Besides, the pressure difference can reach 26.2 mm H2O at the frequency of 6 Hz and the voltage of 160 V. This research proposes a valve-less piezoelectric pump with hemisphere-segment bluff-body, and its validity and feasibility is verified through theoretical analysis and experiment.

  18. Boattail Plates With Non-Rectangular Geometries For Reducing Aerodynamic Base Drag Of A Bluff Body In Ground Effect

    DOEpatents

    Ortega, Jason M.; Sabari, Kambiz

    2006-03-07

    An apparatus for reducing the aerodynamic base drag of a bluff body having a leading end, a trailing end, a top surface, opposing left and right side surfaces, and a base surface at the trailing end substantially normal to a longitudinal centerline of the bluff body, with the base surface joined (1) to the left side surface at a left trailing edge, (2) to the right side surface at a right trailing edge, and (3) to the top surface at a top trailing edge. The apparatus includes left and right vertical boattail plates which are orthogonally attached to the base surface of the bluff body and inwardly offset from the left and right trailing edges, respectively. This produces left and right vertical channels which generate, in a flowstream substantially parallel to the longitudinal centerline, respective left and right vertically-aligned vortical structures, with the left and right vertical boattail plates each having a plate width defined by a rear edge of the plate spaced from the base surface. Each plate also has a peak plate width at a location between top and bottom ends of the plate corresponding to a peak vortex of the respective vertically-aligned vortical structures.

  19. Large eddy simulation of the flow around bluff body with drag reduction device

    NASA Astrophysics Data System (ADS)

    Al-Anazi, Khalid Qaied

    This thesis focuses on the use of LES to simulate the flow around elliptical bluff body with blunt trailing edge fitted with open base cavity. The main objective of this study is to determine the effects of the cavity on the drag of the body. A secondary but important objective is to demonstrate that LES can provide accurate representation of the flow around this bluff body. Moreover, LES results can complement the available experimental results in order to provide a much better understanding of the flow. The simulations were carried out at a Reynolds number of 2.6×104 based on the height of the body using Spalart-Allmaras RANS model while the LES were performed using Smagorinsky dynamic model. A grid-independence test was conducted using three grids which contain 0.85M, 1.3M and 1.7M cells, respectively. This test shows that the results are grid-independent. The LES results predicted the mean flow field in the near wake with good accuracy as compared to the experimental mean flow field obtained. The base pressure results show that the base pressure coefficient for the base model was around -0.56, which agrees well with the experimental results .By attaching the cavity, the base pressure has increased. The increase in base pressure coefficient was around 44% using 1/3 h cavity and this agrees well with the experimental measurements. The RANS predicted drag coefficient of 0.56 for the base model and 0.471 for the cavity model. This represents a difference of 8% for the base model and 34% for the cavity model when compared with experiment drag coefficients (0.61 for the base model and 0.35 for the cavity model). For the LES, the drag coefficient of the base model was around 0.65 (6.5% difference) and using the cavity, the drag coefficient was reduced to around 0.37 (5.74% difference). Details of the mean velocity components have been compared with experimental data at various locations in the wake region of the flow. Observation on the comparison between LES and

  20. Spatio-temporal Dynamics of Coastal Bluff Erosion near Barrow Alaska over the Past Decade

    NASA Astrophysics Data System (ADS)

    Kofoed, K. B.; Lopez, A. F.; Aguirre, A.; Aiken, Q.; Cody, R. P.; Gaylord, A. G.; Manley, W. F.; Green, E.; Nelson, L.; Lougheed, V.; Velasco, A. A.; Tweedie, C. E.

    2014-12-01

    Arctic coastal systems are recognized as being one of the most climate change - vulnerable ecosystems on Earth and represent a complex nexus for examining change at the interface between marine, terrestrial, atmospheric, cryospheric and social systems. Although coastal erosion has received increased attention in the Arctic, few studies have examined the fine scale spatiotemporal dynamics and variability in erosion rates relative to the range of factors that act concomitantly to control erosion (e.g. duration of ice free seas, bathymetry, wave action, sea and air temperature, landscape morphology). This study reports on the spatiotemporal dynamics of annual DGPS surveys of eroding coastal bluffs in northern Alaska near the city of Barrow. Surveys along ca. 11km of the Elson Lagoon coast have been conducted since 2002 and additional surveys along ca. 120km of Elson Lagoon and Chuckhi Sea coast have been conducted since 2013. There has been strong inter-annual spatiotemporal variability in erosion rates with no indication of a long term change in erosion rates over time. Factors controlling wave intensity (e.g. wind run, off shore bathymetry, aspect of the coast relative to prevailing winds) explain most variability in erosion rates over time but during relatively calm periods, landscape history and morphology become more important. These findings highlight the extreme fine scale spatiotemporal heterogeneity in erosion rates along the Arctic Coast, and the importance of incorporating both storm-related climatic events and landscape characteristics when forecasting future environmental states in Arctic coastal landscapes. Case studies outlining new remote sensing technologies and future directions of study will also be outlined including terrestrial and airborne LiDAR, and Kite, UAV, and satellite imagery that is being used to derive and monitor topographic and hydrological change near eroding coastal bluffs; a wireless sensor network of micrometeorological and optical

  1. Laboratory measurements of selected optical, physical, chemical, and remote-sensing properties of five water mixtures containing Calvert clay and a nonfluorescing dye

    NASA Technical Reports Server (NTRS)

    Usry, J. W.; Whitlock, C. H.; Poole, L. R.; Witte, W. G., Jr.

    1981-01-01

    Total suspended solids concentrations ranged from 6.1 ppm to 24.3 ppm and sizes ranged between 1.5 micrometers and 10 micrometers with the most frequently occurring size less than 2 micrometers. Iron concentration was less than 1 percent of the total suspended solids. Nonfluorescing dye concentrations of the two mixtures were 20 ppm and 40 ppm. Attenuation coefficient for the five mixtures ranged from 4.8/m to 21.3/m. Variations in volume scattering function with phase angle were typical. Variations in attenuation and absorption coefficient with wavelength were similar for the mixtures without the dye. Attenuation coefficient of the mixtures with the dye increased for wavelengths less than 600 nm due to the dye's strong absorption peak near 500 nm. Reflectance increased as the concentration of Calvert clay increased and peaked near 600 nm. The nonfluorescent dye decreased the magnitude of the peak, but had practically no effect on the variation for wavelengths greater than 640 nm. At wavelengths less than 600 nm, the spectral variations of the mixtures with the dye were significantly different from those mixtures without the dye.

  2. Quartz and Hydrous Iron Oxides from the Bee Bluff Structure of South Texas

    NASA Astrophysics Data System (ADS)

    Graham, R. A.; Martin, M.; Thadhani, N. N.; Morosin, B.

    2006-07-01

    There is substantial information showing that the Bee Bluff structure is an impact site and that a residual crater can be identified. The thin hard cap of Carrizo Sandstone, Indio fm calcareous silt and a thin layer of iron-rich siltstone leads to impact processes in which the high pressure release wave proceeds promptly upward leading to a trapping of metamorphic products at the impact interface, a `bottom-up' pressure release. Release of water from goethite binder in the sandstone and from the iron-rich siltstone results in supersaturated steam in mixtures with iron and quartz compounds. Samples with quartz and hydrous iron oxide features are examined with optical microscopy, SEM, EDX and XRD. A quartz grain is found with a well defined PDF set. There is widespread amorphous quartz including lechatleriete. Nanocrystals of α-goethite in the acicular form are common. A condensation sphere from the `Uvalde Crater Rosetta Stone' shows a complex mixture of hematite, goethite, and alpha quartz with a trace of trydimite. Numerous samples are yet to be analyzed. The crater appears to have features that can serve as an Earth analog to Mars craters. A companion paper in the present proceedings summarizes prior work, adds new site detail, reports impact-loading analysis, and describes overall features of impactite samples from the site.

  3. Ballography: A Billion Nanosecond History of the Bee Bluff Impact Crater of South Texas

    NASA Astrophysics Data System (ADS)

    Graham, R. A.

    2006-07-01

    The Bee Bluff Structure of South Texas in Zavala County near Uvalde has been found to exhibit unusual features permitting study of impactites and meteorite impact processes from the standpoint of grain-level, nanosecond shock-compression science. The site is characterized by a thin cap of Carrizo Sandstone covering a thin hard Indio fm calcareous siltstone. A soft calcareous silt lies below the hard cap. Calculations based on the Earth Impact Effects web-based program indicate that the site is best described by a 60 m diameter iron meteorite striking the ground at 11 km/sec. Such an impact into sandstone is expected to produce a shock pressure of 250 GPa. A large release wave originates from the bottom of the hard target with upward moving melt-vaporization waves of solid, liquid and vapor products that become trapped at the impact interface. Numerous distinctive types of impactites result from this `bottom-up' release behavior. Evidence for hydrodynamic instabilities and resulting density gradients are abundant at the impact interface. An unusually valuable breccia sample called `The Uvalde Crater Rosetta Stone' contains at least seven types of impactites in a well defined arrangement that can be used to read the billion nanosecond history of the impact and identify scattered impactites relative to their place in that history.

  4. Base pressure prediction in bluff-body potential-flow models

    NASA Astrophysics Data System (ADS)

    Yeung, W. W. H.; Parkinson, G. V.

    2000-11-01

    In a recent study by Yeung & Parkinson (1997), a wake width was proposed which allowed the bluff-body potential-flow model by Parkinson & Jandali (1970) to be extended to include the flow around an oblique flat plate. By incorporating this wake width in the momentum equation originally derived by Eppler (1954) for separated flow, the drag of the plate is related to its inclination and base pressure through a simple analytical condition. It allows the base pressure, which is usually treated as an empirical input, to be determined theoretically and thus the model becomes self-contained. Predictions of the base pressure, drag and width of wake are found to be in reasonable agreement with the experimental data. When applied to the symmetrical flow around a wedge of arbitrary vertex angle, similar agreement with experimental measurements is obtained as well. It is also demonstrated that this condition is compatible with the free-streamline models by Wu (1962) and Wu & Wang (1964) such that the corresponding predictions are in good agreement with experiment.

  5. Dynamical-systems analysis and unstable periodic orbits in reacting flows behind symmetric bluff bodies.

    PubMed

    Hua, Jia-Chen; Gunaratne, Gemunu H; Kostka, Stanislav; Jiang, Naibo; Kiel, Barry V; Gord, James R; Roy, Sukesh

    2013-09-01

    Dynamical systems analysis is performed for reacting flows stabilized behind four symmetric bluff bodies to determine the effects of shape on the nature of flame stability, acoustic coupling, and vortex shedding. The task requires separation of regular, repeatable aspects of the flow from experimental noise and highly irregular, nonrepeatable small-scale structures caused primarily by viscous-mediated energy cascading. The experimental systems are invariant under a reflection, and symmetric vortex shedding is observed throughout the parameter range. As the equivalence ratio-and, hence, acoustic coupling-is reduced, a symmetry-breaking transition to von Karman vortices is initiated. Combining principal-components analysis with a symmetry-based filtering, we construct bifurcation diagrams for the onset and growth of von Karman vortices. We also compute Lyapunov exponents for each flame holder to help quantify the transitions. Furthermore, we outline changes in the phase-space orbits that accompany the onset of von Karman vortex shedding and compute unstable periodic orbits (UPOs) embedded in the complex flows prior to and following the bifurcation. For each flame holder, we find a single UPO in flows without von Karman vortices and a pair of UPOs in flows with von Karman vortices. These periodic orbits organize the dynamics of the flow and can be used to reduce or control flow irregularities. By subtracting them from the overall flow, we are able to deduce the nature of irregular facets of the flows. PMID:24125348

  6. Free surface flow simulation with application to bluff body flow control

    NASA Astrophysics Data System (ADS)

    Kocabiyik, S.; Bozkaya, C.

    2015-03-01

    To better understand the interaction of a free surface wave motion with moving bluff bodies, a two-dimensional numerical study of the forced streamwise oscillation of a circular cylinder beneath a free surface is conducted based on a two-fluid model. Computations are carried out at a Reynolds number of R = 200, a fixed displacement amplitude, A = 0.13 and the forcing frequency-to-natural shedding frequency ratios, f/ f 0 = 1.5,2.5,3.5. Finite volume discretization of the special integral form of two-dimensional continuity and unsteady Navier-Stokes equations (when a solid body is present) are performed on a fixed Cartesian grid. Improved volume-of-fluid method is used to discretize the free surface. The laminar asymmetric flow regimes in the near wake region and the fluid forces are analyzed at a fixed Froude number of Fr = 0.4 and for submergence depths at h = 0.25,0.5,0.75. A comparison of the present results with the case in the absence of a free surface is also included to illustrate the effects of inclusion of a free surface. The code validation in special cases shows good comparisons with previous numerical and experimental results. Flow regime analyses include free surface physics-based analysis, and results confirm findings of a recent work of Brøns et al. [25].

  7. Comparative study of micromixing models in transported scalar PDF simulations of turbulent nonpremixed bluff body flames

    SciTech Connect

    Merci, Bart; Roekaerts, Dirk; Naud, Bertrand; Pope, Stephen B.

    2006-07-15

    Numerical simulation results are presented for turbulent jet diffusion flames with various levels of turbulence-chemistry interaction, stabilized behind a bluff body (Sydney Flames HM1-3). Interaction between turbulence and combustion is modeled with the transported joint-scalar PDF approach. The mass density function transport equation is solved in a Lagrangian manner. A second-moment-closure turbulence model is applied to obtain accurate mean flow and turbulent mixing fields. The behavior of two micromixing models is discussed: the Euclidean minimum spanning tree model and the modified Curl coalescence dispersion model. The impact of the micromixing model choice on the results in physical space is small, although some influence becomes visible as the amount of local extinction increases. Scatter plots and profiles of conditional means and variances of thermochemical quantities, conditioned on the mixture fraction, are discussed both within and downstream of the recirculation region. A distinction is made between local extinction and incomplete combustion, based on the CO species mass fraction. The differences in qualitative behavior between the micromixing models are explained and quantitative comparison to experimental data is made. (author)

  8. A rotating, bluff-body disc for reduced variability in wind tunnel aerosol studies

    PubMed Central

    Koehler, Kirsten A.; Anthony, T. Renee; van Dyke, Michael; Volckens, John

    2016-01-01

    A rotating bluff-body disc (RBD) was developed to reduce spatiotemporal variability associated with sampling supermicron aerosol in low-velocity wind tunnels. The RBD is designed to rotate eight personal aerosol samplers around a circular path in a forward-facing plane aligned with the wind tunnel cross section. Rotation of the RBD allows each sampler to traverse an identical path about the wind tunnel cross section, which reduces the effects of spatial heterogeneity associated with dispersing supermicron aerosol in low-velocity wind tunnels. Samplers are positioned on the face of the RBD via sampling ports, which connect to an air manifold on the back of the disc. Flow through each sampler was controlled with a critical orifice or needle valve, allowing air to be drawn through the manifold with a single pump. A metal tube, attached to this manifold, serves as both the axis of rotation and the flow conduction path (between the samplers and the vacuum source). Validation of the RBD was performed with isokinetic samplers and 37-mm cassettes. For facing-the-wind tests, the rotation of the RBD significantly decreased intra-sampler variability when challenged with particle diameters from 1 to 100 μm. The RBD was then employed to determine the aspiration efficiency of Institute of Occupational Medicine (IOM) personal samplers under a facing-the-wind condition. Operation of IOM samplers on the RBD reduced the between-sampler variability for all particle sizes tested. PMID:21097990

  9. Large eddy simulation of forced ignition of an annular bluff-body burner

    SciTech Connect

    Subramanian, V.; Domingo, P.; Vervisch, L.

    2010-03-15

    The optimization of the ignition process is a crucial issue in the design of many combustion systems. Large eddy simulation (LES) of a conical shaped bluff-body turbulent nonpremixed burner has been performed to study the impact of spark location on ignition success. This burner was experimentally investigated by Ahmed et al. [Combust. Flame 151 (2007) 366-385]. The present work focuses on the case without swirl, for which detailed measurements are available. First, cold-flow measurements of velocities and mixture fractions are compared with their LES counterparts, to assess the prediction capabilities of simulations in terms of flow and turbulent mixing. Time histories of velocities and mixture fractions are recorded at selected spots, to probe the resolved probability density function (pdf) of flow variables, in an attempt to reproduce, from the knowledge of LES-resolved instantaneous flow conditions, the experimentally observed reasons for success or failure of spark ignition. A flammability map is also constructed from the resolved mixture fraction pdf and compared with its experimental counterpart. LES of forced ignition is then performed using flamelet fully detailed tabulated chemistry combined with presumed pdfs. Various scenarios of flame kernel development are analyzed and correlated with typical flow conditions observed in this burner. The correlations between, velocities and mixture fraction values at the sparking time and the success or failure of ignition, are then further discussed and analyzed. (author)

  10. Stability of the laminar wake behind spinning axisymmetric bluff bodies: sensitivity and control

    NASA Astrophysics Data System (ADS)

    Jimenez-Gonzalez, Jose Ignacio; Martinez-Bazan, Carlos; Coenen, Wilfried; Manglano, Carlos; Sevilla, Alejandro

    2014-11-01

    We carry out direct and adjoint global stability analyses of the laminar wake behind several spinning axisymmetric bluff bodies, i.e. sphere, hemisphere, bullet-shaped bodies of ellipsoidal nose and spherical nose respectively; for moderate Reynolds numbers (Re <= 450) and values of the spin parameter (Ω <= 1), defined as the ratio between the azimuthal velocity at the outer body surface and the free-stream velocity. Both the axisymmetric base flow computations and the assembling of the eigenvalue problems are tackled by means of the finite element solver FreeFEM + + , computing finally the eigenmodes with an Arnoldi algorithm in Matlab. We show that spin acts as a stabilization mechanism for the wake behind bodies with a cylindrical trailing part, while it destabilizes the wake of the other geometries. The computation of the adjoint modes and the identification of the wavemaker allow us to discuss the nature of the different unstable modes found and understand the differences in the stabilizing or destabilizing effect of rotation due to the base flow modifications. The controllability of the unstable regimes by means of base bleed is also addressed. Supported by the Spanish MINECO, Junta de Andalucía and EU Funds under Projects DPI2011-28356-C03-03 and P11-TEP7495.

  11. Erosional history of Cape Halkett and contemporary monitoring of bluff retreat, Beaufort Sea coast, Alaska

    USGS Publications Warehouse

    Jones, Benjamin M.; Arp, Christopher D.; Beck, Richard A.; Grosse, Guido; Webster, James M.; Urban, Frank E.

    2009-01-01

    Cape Halkett is located along the Beaufort Sea at the end of a low-lying tundra landscape. The area has been subject to major modifications over the last century as a result of erosion and migration of the coastline inland. Long-term mean annual erosion rates (1955-2009) for the entire cape are 7.6 m/yr, with a gradual increase in rates over the first five time periods of remotely sensed imagery analyzed and a large increase during the most recent time period. Division of the cape into three distinct coastal zones shows very different erosional patterns: the northeast-facing segment (Zone 1) showing a consistent and large increase; the southeast-facing segment (Zone 3) showing a gradual increase with recent, heightened erosion rates; and the east-facing segment (Zone 2) showing decreased rates due to the reformation of a sand and gravel spit. Monitoring of bluff erosion with time-lapse photography, differential GPS surveys, terrestrial and bathymetric surveys, and water level, sea and permafrost temperature data provide insights into the processes driving contemporary patterns of erosion and will provide valuable information for the prediction of future shoreline positions.

  12. Detailed Ar-Ar Geochronology of Volcanism at Minna Bluff, Antarctica: Two-Phased Growth and Influence on Ross Ice Shelf

    NASA Astrophysics Data System (ADS)

    Ross, J. I.; McIntosh, W. C.; Wilch, T. I.

    2012-12-01

    Minna Bluff has been a significant topographic barrier to the flow of the Ross Ice Shelf since the mid-Miocene. Detailed Ar-Ar analyses of kaersutite and sanidine phenocrysts, and groundmass concentrates from volcanic units indicate an overall west to east progression of volcanic activity. Eruptions of basaltic to intermediate lavas, domes, and scoria cones started at ~12 Ma in at what is now the eastern most point of Minna Bluff, "Minna Hook." Activity was centered in this area for ~4 Ma, constructing a pre-Minna Bluff island. Multiple glacial unconformities found at Minna Hook suggest repeated interaction with large warm-based, erosive ice sheets. Activity migrated westward from Minna Bluff Island at 7-8 Ma closing the gap created by the island and the mainland. Significant edifice construction continued until 4-5 Ma with sporadic and parasitic scoria cone eruptions, possibly associated with Mt. Discovery activity, continuing until 2 Ma. The orientations of Minna Bluff's two major axes are strongly controlled by regional tectonic features. Minna Bluff's E-W axis, McIntosh Cliffs, is sub-parallel to the Radial Lineament and the N-S axis, Minna Hook, appears as extension of faulting bounding the Terror Rift. The constructional evolution of the 70km long volcanic complex has an important role in interpreting the climate signals recovered by the ANDRILL Project. Minna Bluff influenced the material delivered to the AND-1B drill site (ANDRILL MIS 2006-2007) in three critical ways: 1) Minna Bluff diverted upstream material, 2) provided a pinning and stabilizing point for the Ross Ice Shelf, possible controlling the calving line prior to the emergence of Ross Island, and 3) was a significant source of fresh volcanic material throughout much of the period recovered by ANDRILL MIS. For example, a kaersutite-bearing clast recovered from 822.78 mbsf in AND-1B yielded an age of 8.53±0.51 Ma, and was likely derived from Minna Bluff. The results from this study can be

  13. Paleomagnetic and 40Ar/39Ar results from the Grant intrusive breccia and coparison to the Permian Downeys Bluff Sill; evidence for Permian igneous activity at Hicks Dome, southern Illinois Basin

    USGS Publications Warehouse

    Reynolds, Richard L.; Goldhaber, Martin B.; Snee, Lawrence W.

    1997-01-01

    Igneous processes at Hicks dome, a structural upwarp at lat 37.5 degrees N., long 88.4 degrees W. in the southern part of the Illinois Basin, may have thermally affected regional basinal fluid flow and may have provided fluorine for the formation of the Illinois-Kentucky Fluorspar district. The timing of both igneous activity and mineralization is poorly known. For this reason, we have dated an intrusive breccia at Hicks dome, the Grant intrusion, using 40Ar/39Ar geochronometric and paleomagnetic methods. Concordant plateau dates, giving Permian ages, were obtained from amphibole (272.1+or-0.7 [1 sigma] Ma) and phlogopite (272.7+or-0.7 [1 sigma] Ma). After alternating-field (AF) demagnetization, specimens that contain titanomagnetite-bearing igneous rock fragments give a mean remanent direction of declination (D)=168.4 degrees; inclination (I)=-8 degrees; alpha 95=8.6 degrees; number of specimens (N)=10; this direction yields a virtual geomagnetic pole (VGP) at lat 54.8 degrees N., long 119.0 degrees E., delta p=4.4 degrees, delta m=8.7 degrees, near the late Paleozoic part of the North American apparent pole wander path. A nearly identical magnetization was found for the nearby Downeys Bluff sill (previously dated at about 275+or-24 Ma by the Rb-Sr method), in southern Illinois. Both AF and thermal demagnetization isolated shallow, southeasterly remanent directions carried by magnetite in the sill and from pyrrhotite in the baked contact of the Upper Mississippian Downeys Bluff Limestone: D=158.6 degrees; I=-11.8 degrees; alpha 95=3.8 degrees; N=15, yielding a VGP at lat 53.0 degrees N., long 128.7 degrees E., delta p=2.0 degrees, delta m=3.9 degrees. The paleomagnetic results, isotopic dates, and petrographic evidence thus favor the acquisition of thermal remanent magnetization by the Grant breccia and the Downeys Bluff sill during the Permian. The isotopic dates record rapid cooling from temperatures greater than 550 degrees C to less than 300 degrees C (the

  14. Nonlinear hydrodynamic and thermoacoustic oscillations of a bluff-body stabilised turbulent premixed flame

    NASA Astrophysics Data System (ADS)

    Lee, Chin Yik; Li, Larry Kin Bong; Juniper, Matthew P.; Cant, Robert Stewart

    2016-01-01

    Turbulent premixed flames often experience thermoacoustic instabilities when the combustion heat release rate is in phase with acoustic pressure fluctuations. Linear methods often assume a priori that oscillations are periodic and occur at a dominant frequency with a fixed amplitude. Such assumptions are not made when using nonlinear analysis. When an oscillation is fully saturated, nonlinear analysis can serve as a useful avenue to reveal flame behaviour far more elaborate than period-one limit cycles, including quasi-periodicity and chaos in hydrodynamically or thermoacoustically self-excited system. In this paper, the behaviour of a bluff-body stabilised turbulent premixed propane/air flame in a model jet-engine afterburner configuration is investigated using computational fluid dynamics. For the frequencies of interest in this investigation, an unsteady Reynolds-averaged Navier-Stokes approach is found to be appropriate. Combustion is represented using a modified laminar flamelet approach with an algebraic closure for the flame surface density. The results are validated by comparison with existing experimental data and with large eddy simulation, and the observed self-excited oscillations in pressure and heat release are studied using methods derived from dynamical systems theory. A systematic analysis is carried out by increasing the equivalence ratio of the reactant stream supplied to the premixed flame. A strong variation in the global flame structure is observed. The flame exhibits a self-excited hydrodynamic oscillation at low equivalence ratios, becomes steady as the equivalence ratio is increased to intermediate values, and again exhibits a self-excited thermoacoustic oscillation at higher equivalence ratios. Rich nonlinear behaviour is observed and the investigation demonstrates that turbulent premixed flames can exhibit complex dynamical behaviour including quasiperiodicity, limit cycles and period-two limit cycles due to the interactions of various

  15. Drag reduction on a rectangular bluff body with base flaps and fluidic oscillators

    NASA Astrophysics Data System (ADS)

    Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

    2015-07-01

    The present paper investigates drag reduction on a rectangular bluff body by employing base flaps and controlling flow separation with fluidic oscillators. Wind tunnel experiments are conducted to assess the influence of various parameters. The flap length has to be sufficiently long to shift the wake structures far enough downstream away from the base plate. Any additional increase in flap length does not yield any further benefits. The flap angle has to be large enough to provide a sufficient inward deflection of the outer flow. If the angle is too large, actuation becomes inefficient due to the pressure gradient imposed by the opposite side of the base perimeter. Furthermore, the flaps at high deflection angles provide additional area for low pressure to act in the streamwise direction and therefore negate the positive effects of actuation. The required actuation intensity is best governed by the ratio between jet and freestream velocity for varying oscillator spacing. For a flap angle of 20°, the smallest net drag is obtained at a velocity ratio of 4.5. Furthermore, the optimal velocity ratio for the most efficient drag reduction changes linearly with flap angle. Smaller flap deflections require a smaller velocity ratio for optimal control at different oscillator spacing. A net drag reduction of about 13 % is measured at a flap angle of 20° when the drag is corrected by the momentum input. Even if the measured drag is conservatively corrected by the energy coefficient, a net improvement of 7 % is achieved. For the current setup, the most efficient drag reduction is still obtained at smaller flap angles with a lower momentum input. However, the presented results support the general feasibility of this drag reduction approach with significant room left for optimization.

  16. Petrogenesis of alkaline magmas at Minna Bluff, Antarctica: evidence for multi-stage differentiation and complex mixing processes

    NASA Astrophysics Data System (ADS)

    Panter, K. S.; Dunbar, N. W.; Scanlan, M. K.; Wilch, T. I.; Fargo, A. J.; McIntosh, W. C.

    2011-12-01

    Minna Bluff, a 45-km-long peninsula that extends SE into the Ross Ice Shelf from the Mt. Discovery stratovolcano, consists of coalesced late Miocene volcanic centers formed through eruption of alkaline magma compositions in a continental rift setting. Highly silica-undersaturated compositions vary from basanite to phonolite and are exposed in volcanic features ranging from small, primitive, cinder cones to large, evolved domes. Lava compositions are more evolved on the eastern end of Minna Bluff and show an overall age progression to younger, more mafic compositions towards Mt. Discovery. Phenocrysts in lava include amphibole, plagioclase and alkali feldspar, pyroxene, olivine, magnetite and apatite. A notable feature of volcanic rocks at Minna Bluff is the presence of large (up to 5 cm) kaersutite and feldspar megacrysts and deposits that contain abundant comagmatic inclusions (kaersutite-rich) and rare mantle xenoliths. Many lavas exhibit strong disequilibrium textures, mainly expressed by breakdown rims on kaersutite that vary dramatically in thickness from crystal to crystal, but reverse compositional zoning in plagioclase is also common. Kaersutite compositions vary within a single sample and show the same compositional range and similar disequilibrium textures in rocks that vary significantly in bulk composition. The textural and compositional characteristics suggest that, for many, mixing between one or more magmas controlled the final composition of the magmas. We envisage a scenario by which some of the primitive, mantle-derived, fluid-rich magmas rose relatively unimpeded to erupt at the surface, while others stalled at or near the crust-mantle boundary and differentiated. Semi-quantitative thermobarometric results for kaersutite and clinopyroxene indicate maximum P-T-X conditions for crystallization of hydrous magmas at 5-9 kbar, ≧1000°C and ≈3 wt. % equiv. H2O. The P-T estimates closely match geophysical and petrologic geotherm estimates for Moho

  17. Scappoose Formation, Columbia County, Oregon: new evidence of age and relation to Columbia River basalt group

    SciTech Connect

    VanAtta, R.O.; Kelty, K.B.

    1985-05-01

    The Scappoose Formation, considered to be late Oligocene to early Miocene in age, was originally believed to be disconformably separated from both the underlying Pittsburg Bluff Formation and the overlying Yakima subgroup of the Columbia River Basalt Group. Recent mapping and petrography show that it lies disconformably on both the Keasey and Pittsburg Bluff Formations, and interfingers with the Yakima Basalt. The Scappoose is composed of fluvial sandstone, conglomerate, and carbonaceous to coal-bearing mud rock, intertongued with shallow neritic to estuarine siltstone, mud rock, and minor sandstone. Chemistry of basalt clasts from fluvial conglomerates reveals that they are derived from the Yakima subgroup. Basalt conglomerate and palagonitic sediments in the upper part of the formation are intercalated with Grande Ronde basalt (Yakima subgroup) flows at many localities. Flows of Yakima Basalt are also invasive into originally wet, unconsolidated Scappoose sediment. Grande Ronde basalt and the Frenchman Springs Member of the Wanapum basalt overlie conglomerate of the Scappoose. In places, the Scappoose Formation is absent, and Yakima Basalt lies directly on the Pittsburg Bluff and Keasey Formations. The thickness of both the Scappoose Formation and the Columbia River Basalt Group varies widely, indicating that both were deposited over a paleotopography with a relief up to 800 ft (245 m). The definition of the boundaries of the Scappoose Formation should be revised, owing to the disconformable relation of the Scappoose to both the underlying Keasey and Pittsburg Bluff Formations and to the Scappoose's intercalation with the overlying Yakima Basalt. Definition of age must also be revised, inasmuch as sedimentation of the formation was coeval with Columbia River Basalt volcanism.

  18. The extraction and utilization of local and scientific geospatial knowledge within the Bluff oyster fishery, New Zealand.

    PubMed

    Hall, G Brent; Moore, Antoni; Knight, Peter; Hankey, Nick

    2009-05-01

    This paper assesses the Bluff oyster fishery in New Zealand as a case study in common pool resource management. It discusses ways in which modern information technology, augmented by low-tech data gathering strategies and community ethnography, can be used to produce an integrated scientific and local knowledge-inspired fishery database that lends itself to fostering collaboration in resource management and planning. The specific context and state of the oyster fishery in Bluff are described. Issues regarding undocumented and ephemeral intergenerational knowledge, much of which is geospatial in nature, on the fishery, the current crisis that many see in the future of the fishery, and a lack of cohesion or common sense of purpose between the stakeholder groups are discussed. It is argued that the digital resource that results from the integration of local and scientific knowledge and the potential community building processes that can ensue from collaboration and dialogue around this centrepiece are of central importance in developing an oyster fishery management plan that is holistic in concept and sustainable in purpose. PMID:18760525

  19. Environmental Assessment of the Gering-Stegall 115-kV Transmission Line Consolidation Project, Scotts Bluff County, Nebraska

    SciTech Connect

    1995-05-01

    The Department of Energy (DOE), Western Area Power Administration (Western) proposes to consolidate segments of two transmission lines near the Gering Substation in Gering, Nebraska. The transmission lines are both located in Scotts Bluff County, Nebraska. The transmission lines are both located in Scotts Bluff County, Nebraska, within the city of Gering. Presently, there are three parallel 115-kilovolt (kV) transmission lines on separate rights-of-way (ROW) that terminate at the Gering Substation. The project would include dismantling the Archer-Gering wood-pole transmission line and rebuilding the remaining two lines on single-pole steel double circuit structures. The project would consolidate the Gering-Stegall North and Gering-Stegall South 115-kV transmission lines on to one ROW for a 1.33-mile segment between the Gering Substation and a point west of the Gering Landfill. All existing wood-pole H-frame structures would be removed, and the Gering-Stegall North and South ROWs abandoned. Western is responsible for the design, construction, operation, and maintenance of the line. Western prepared an environmental assessment (EA) that analyzed the potential environmental impacts of the proposed construction, operation, and maintenance of the 115-kV transmission line consolidation. Based on the analyses in the EA, the DOE finds that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act of 1969 (NEPA).

  20. Transfer function characteristics of bluff-body stabilized, conical V-shaped premixed turbulent propane-air flames

    SciTech Connect

    Chaparro, Andres; Landry, Eric; Cetegen, Baki M.

    2006-04-15

    The response of bluff-body stabilized conical V-shaped premixed flames to periodic upstream velocity oscillations was characterized as a function of oscillation frequency, mean flow velocity, and equivalence ratio. The flame heat release response to the imposed velocity oscillations was determined from the CH* chemiluminescence captured by two photomultiplier (PMT) detectors at a wavelength of 430 nm. One of the PMTs viewed flame radiation in a 10-mm horizontal slice, 50 mm above the bluff-body. The second PMT observed the overall flame radiation. The flame transfer function characteristics were determined from the spectral analysis of the velocity and PMT signals. It was found that the flame heat release amplitude response is confined to low-frequency excitation below a Strouhal number of 4. The phase relationship of the transfer function for these turbulent flames was evaluated using the signal from the spatially masked PMT. The transfer function estimate based on these data exhibits second-order characteristics with a phase lag between the velocity and heat release signals. The localized heat-release response contains frequencies that are multiples of the excitation frequency, suggesting splitting and tilting of flame structures as well as some nonlinear effects. Increase of flame equivalence ratio from lean toward stoichiometric resulted in slight amplification of the high-frequency response. (author)

  1. Calculations of the flow past bluff bodies, including tilt-rotor wing sections at alpha = 90 deg

    NASA Technical Reports Server (NTRS)

    Raghavan, V.; Mccroskey, W. J.; Baeder, J. D.; Van Dalsem, W. R.

    1990-01-01

    An attempt was made to model in two dimensions the effects of rotor downwash on the wing of the tilt-rotor aircraft and to compute the drag force on airfoils at - 90 deg angle of attack, using a well-established Navier-Stokes code. However, neither laminar nor turbulent calculations agreed well with drag and base-pressure measurements at high Reynolds numbers. Therefore, further efforts were concentrated on bluff-body flows past various shapes at low Reynolds numbers, where a strong vortex shedding is observed. Good results were obtained for a circular cylinder, but the calculated drag of a slender ellipse at right angles to the freestream was significantly higher than experimental values reported in the literature for flat plates. Similar anomalous results were obtained on the tilt-rotor airfoils, although the qualitative effects of flap deflection agreed with the wind tunnel data. The ensemble of results suggest that there may be fundamental differences in the vortical wakes of circular cylinders and noncircular bluff bodies.

  2. Global mode analysis of axisymmetric bluff-body wakes: Stabilization by base bleed

    NASA Astrophysics Data System (ADS)

    Sanmiguel-Rojas, E.; Sevilla, A.; Martínez-Bazán, C.; Chomaz, J.-M.

    2009-11-01

    The flow around a slender body with a blunt trailing edge is unstable in most situations of interest. Usually the flow instabilities are generated within the wake behind the bluff body, inducing fluctuating forces and introducing the possibility of resonance mechanisms with modes of the structure. Base bleed is a simple and well-known means of stabilizing the wake. In the present research, we investigate the global instability properties of the laminar-incompressible flow that develops behind a cylinder with sharp edges and axis aligned with the free stream using a spectral domain decomposition method. In particular, we describe the flow instability characteristics as a function of the Reynolds number, Re=ρW∞D/μ, and the bleed coefficient, defined as the bleed-to-free-stream velocity ratio, Cb=Wb/W∞, where D is the diameter of the body and ρ and μ the density and viscosity of the free stream, respectively. For a truncated cylinder of aspect ratio L /D=5, where L is the length of the body, our calculations reveal the presence of a first steady bifurcation in the wake at Re≃391, as well as a second oscillatory one at Re≃715 with an associated Strouhal number St≃0.0905 for the most unstable azimuthal mode |m|=1. In addition, we report the existence of two critical values of the bleed coefficient Cb1∗(Re,|m |) and Cb2∗(Re,|m |)

  3. Advances in Turbulent Combustion Dynamics Simulations in Bluff-Body Stabilized Flames

    NASA Astrophysics Data System (ADS)

    Tovar, Jonathan Michael

    This work examines the three main aspects of bluff-body stabilized flames: stationary combustion, lean blow-out, and thermo-acoustic instabilities. For the cases of stationary combustion and lean blow-out, an improved version of the Linear Eddy Model approach is used, while in the case of thermo-acoustic instabilities, the effect of boundary conditions on the predictions are studied. The improved version couples the Linear Eddy Model with the full-set of resolved scale Large Eddy Simulation equations for continuity, momentum, energy, and species transport. In traditional implementations the species equations are generally solved using a Lagrangian method which has some significant limitations. The novelty in this work is that the Eulerian species concentration equations are solved at the resolved scale and the Linear Eddy Model is strictly used to close the species production term. In this work, the improved Linear Eddy Model approach is applied to predict the flame properties inside the Volvo rig and it is shown to over-predict the flame temperature and normalized velocity when compared to experimental data using a premixed single step global propane reaction with an equivalence ratio of 0.65. The model is also applied to predict lean blow-out and is shown to predict a stable flame at an equivalence ratio of 0.5 when experiments achieve flame extinction at an equivalence ratio of 0.55. The improved Linear Eddy Model is, however, shown to be closer to experimental data than a comparable reactive flow simulation that uses laminar closure of the species source terms. The thermo-acoustic analysis is performed on a combustor rig designed at the Air Force Research Laboratory. The analysis is performed using a premixed single step global methane reaction for laminar reactive flow and shows that imposing a non-physical boundary condition at the rig exhaust will result in the suppression of acoustic content inside the domain and can alter the temperature contours in non

  4. Modeling 3-D Slope Stability of Coastal Bluffs Using 3-D Ground-Water Flow, Southwestern Seattle, Washington

    USGS Publications Warehouse

    Brien, Dianne L.; Reid, Mark E.

    2007-01-01

    Landslides are a common problem on coastal bluffs throughout the world. Along the coastal bluffs of the Puget Sound in Seattle, Washington, landslides range from small, shallow failures to large, deep-seated landslides. Landslides of all types can pose hazards to human lives and property, but deep-seated landslides are of significant concern because their large areal extent can cause extensive property damage. Although many geomorphic processes shape the coastal bluffs of Seattle, we focus on large (greater than 3,000 m3), deepseated, rotational landslides that occur on the steep bluffs along Puget Sound. Many of these larger failures occur in advance outwash deposits of the Vashon Drift (Qva); some failures extend into the underlying Lawton Clay Member of the Vashon Drift (Qvlc). The slope stability of coastal bluffs is controlled by the interplay of three-dimensional (3-D) variations in gravitational stress, strength, and pore-water pressure. We assess 3-D slope-stability using SCOOPS (Reid and others, 2000), a computer program that allows us to search a high-resolution digital-elevation model (DEM) to quantify the relative stability of all parts of the landscape by computing the stability and volume of thousands of potential spherical failures. SCOOPS incorporates topography, 3-D strength variations, and 3-D pore pressures. Initially, we use our 3-D analysis methods to examine the effects of topography and geology by using heterogeneous material properties, as defined by stratigraphy, without pore pressures. In this scenario, the least-stable areas are located on the steepest slopes, commonly in Qva or Qvlc. However, these locations do not agree well with observations of deep-seated landslides. Historically, both shallow colluvial landslides and deep-seated landslides have been observed near the contact between Qva and Qvlc, and commonly occur in Qva. The low hydraulic conductivity of Qvlc impedes ground-water flow, resulting in elevated pore pressures at the

  5. A revision of Metaleptobasis Calvert (Odonata: Coenagrionidae) with seven synonymies and the description of eighteen new species from South America.

    PubMed

    Von Ellenrieder, Natalia

    2013-01-01

    Examination of over 1,400 specimens of the neotropical genus Metaleptobasis Calvert, 1907, including primary types or paratypes of 18 of the 20 currently available species names and large series of specimens including pairs in tandem and copula, allowed me to unequivocally associate older names with species, distinguish between specific and intraspecific variability, associate both sexes for each species, and recognize the existence of female polymorphism. As a result, seven names are found to be junior synonyms: Metaleptobasis mauritia Williamson, 1915 junior synonym of M. bicornis (Selys, 1877), M. manicaria Williamson, 1915 and M. fernandezi Rácenis, 1955 junior synonyms of M. diceras (Selys, 1877), M. westfalli Cumming, 1954 junior synonym of M. foreli Ris, 1915, and M. tetragena Calvert, 1947, M. weibezahni Rácenis, 1955, and M. incisula De Marmels, 1989 junior synonyms of M. brysonima Williamson, 1915. Lectotypes are designated for M. amazonica and Leptobasis diceras. Eighteen new species of Metaleptobasis are described: M. brevicauda (Holotype ♂, Peru, Huánuco Dep., Shapajilla, jungle, 11 v 1939, F. Woytkowski leg., in UMMZ); M. falcifera (Holotype ♂, Peru, Madre De Dios Dep., Pakitza, Reserved Zone, Manu National Park, T2 to R2 to T1 to base camp, 11°55'48''S, 71°15'18''W, 250 m, 17 ix 1989, J.A. Louton leg., in USNM); M. furcifera (Holotype ♂, Peru, Loreto Dep., Iquitos, iii 1936, G.G. Klug leg., in BMNH); M. gabrielae (Holotype ♂, Peru, Loreto Dep., Tamshiyacu-Tahuayo Reserve, forest interior (4°23'40''S, 73°14'56''W), 27 vii 2009, T. Faasen leg., in RMNH); M. guillermoi (Holotype ♂, Peru, Loreto Dep., Yarinacocha, temporary forest stream (8°17'S, 74°37'W, 145 m), 2 vi 1972, D.L. Pearson leg., in FSCA); M. inermis (Holotype ♂, Brazil, Pará State, Jacareacanga, vii 1969, F.R. Barbosa leg., in UMMZ); M. leniloba (Holotype ♂, Peru, Loreto Dep., Pacaya-Samiria National Reserve, Santa Luisa trail (5°15'S, 74°40'W), 10 vi 2008, C

  6. Vortex dynamics and scalar transport in the wake of a bluff body driven through a steady recirculating flow

    NASA Astrophysics Data System (ADS)

    Poussou, Stephane B.; Plesniak, Michael W.

    2012-09-01

    The air ventilation system in wide-body aircraft cabins provides passengers with a healthy breathing environment. In recent years, the increase in global air traffic has amplified contamination risks by airborne flu-like diseases and terrorist threats involving the onboard release of noxious materials. In particular, passengers moving through a ventilated cabin may transport infectious pathogens in their wake. This paper presents an experimental investigation of the wake produced by a bluff body driven through a steady recirculating flow. Data were obtained in a water facility using particle image velocimetry and planar laser induced fluorescence. Ventilation attenuated the downward convection of counter-rotating vortices produced near the free-end corners of the body and decoupled the downwash mechanism from forward entrainment, creating stagnant contaminant regions.

  7. "To Bluff like a Man or Fold like a Girl?" - Gender Biased Deceptive Behavior in Online Poker.

    PubMed

    Palomäki, Jussi; Yan, Jeff; Modic, David; Laakasuo, Michael

    2016-01-01

    Evolutionary psychology suggests that men are more likely than women to deceive to bolster their status and influence. Also gender perception influences deceptive behavior, which is linked to pervasive gender stereotypes: women are typically viewed as weaker and more gullible than men. We assessed bluffing in an online experiment (N = 502), where participants made decisions to bluff or not in simulated poker tasks against opponents represented by avatars. Participants bluffed on average 6% more frequently at poker tables with female-only avatars than at tables with male-only or gender mixed avatars-a highly significant effect in games involving repeated decisions. Nonetheless, participants did not believe the avatar genders affected their decisions. Males bluffed 13% more frequently than females. Unlike most economic games employed exclusively in research contexts, online poker is played for money by tens of millions of people worldwide. Thus, gender effects in bluffing have significant monetary consequences for poker players. PMID:27383472

  8. "To Bluff like a Man or Fold like a Girl?" – Gender Biased Deceptive Behavior in Online Poker

    PubMed Central

    Palomäki, Jussi; Yan, Jeff; Modic, David; Laakasuo, Michael

    2016-01-01

    Evolutionary psychology suggests that men are more likely than women to deceive to bolster their status and influence. Also gender perception influences deceptive behavior, which is linked to pervasive gender stereotypes: women are typically viewed as weaker and more gullible than men. We assessed bluffing in an online experiment (N = 502), where participants made decisions to bluff or not in simulated poker tasks against opponents represented by avatars. Participants bluffed on average 6% more frequently at poker tables with female-only avatars than at tables with male-only or gender mixed avatars—a highly significant effect in games involving repeated decisions. Nonetheless, participants did not believe the avatar genders affected their decisions. Males bluffed 13% more frequently than females. Unlike most economic games employed exclusively in research contexts, online poker is played for money by tens of millions of people worldwide. Thus, gender effects in bluffing have significant monetary consequences for poker players. PMID:27383472

  9. Valve replacement at Calvert Cliffs

    SciTech Connect

    Sponsel, J.R.; Boone, K.R.; Simpson, A.L.

    1994-01-01

    This article describes how new valves helped solve plant`s chronic salt water system problems resulting from years of design changes required by regulations that resulted in operational efficiency-related problems. The topics of the article include harsh service conditions (salt water related corrosion, biological fouling and tearing of rubber liners of valves), spare parts headaches and the permanent solution.

  10. Reconnaissance of Acid Drainage Sources and Preliminary Evaluation of Remedial Alternatives at the Copper Bluff Mine, Hoopa Valley Reservation, California

    USGS Publications Warehouse

    Alpers, Charles N.; Hunerlach, Michael P.; Hamlin, Scott N.; Zierenberg, Robert A.

    2003-01-01

    Acidic drainage from the inactive Copper Bluff mine cascades down a steep embankment into the Trinity River, on the Hoopa Valley Reservation in northern California. The Copper Bluff mine produced about 100,000 tons of sulfide-bearing copper-zinc-gold-silver ore during 1957?1962. This report summarizes the results of a water-resources investigation begun by the U.S. Geological Survey in 1994 with the overall objective of gathering sufficient geochemical, hydrologic, and geologic information so that a sound remediation strategy for the Copper Bluff mine could be selected and implemented by the Hoopa Valley Tribe. This study had the following specific objectives: (1) monitor the quality and quantity of the mine discharge, (2) determine seasonal variability of metal concentrations and loads, (3) map and sample the underground mine workings to determine sources of flow and suitability of mine plugging options, and (4) analyze the likely consequences of various remediation and treatment options. Analysis of weekly water samples of adit discharge over parts of two wet seasons (January to July 1995 and October 1995 to May 1996) shows that dissolved copper (Cu) and zinc (Zn) concentrations (in samples filtered with 0.20-micrometer membranes) varied systematically in a seasonal pattern. Metal concentrations increased dramatically in response to the first increase in discharge, or first flush, early in the wet season. The value of Zn/Cu in the adit discharge exhibited systematic seasonal variations; an annual Zn/Cu cycle was observed, beginning with values between 3 and 5 during the main part of the wet season, rising to values between 6 and 10 during the period of lowest discharge late in the dry season, and then dropping dramatically to values less than 3 during the first-flush period. Values of pH were fairly constant in the range of 3.1 to 3.8 throughout the wet season and into the beginning of the dry season, but rose to values between 4.5 and 5.6 during the period of

  11. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Final report

    SciTech Connect

    1995-11-01

    The National Energy Strategy Plan (NES) has called for 900,000 barrels/day production of heavy oil in the mid-1990s to meet our national needs. To achieve this goal, it is important that the Alaskan heavy oil fields be brought to production. Alaska has more than 25 billion barrels of heavy oil deposits. Conoco, and now BP Exploration have been producing from Schrader Bluff Pool, which is part of the super heavy oil field known as West Sak Field. Schrader Bluff reservoir, located in the Milne Point Unit, North Slope of Alaska, is estimated to contain up to 1.5 billion barrels of (14 to 21{degrees}API) oil in place. The field is currently under production by primary depletion; however, the primary recovery will be much smaller than expected. Hence, waterflooding will be implemented earlier than anticipated. The eventual use of enhanced oil recovery (EOR) techniques, such as hydrocarbon miscible solvent slug injection process, is vital for recovery of additional oil from this reservoir. The purpose of this research project was to determine the nature of miscible solvent slug which would be commercially feasible, to evaluate the performance of the hydrocarbon miscible solvent slug process, and to assess the feasibility of this process for improved recovery of heavy oil from Schrader Bluff reservoir. The laboratory experimental work includes: slim tube displacement experiments and coreflood experiments. The components of solvent slug includes only those which are available on the North Slope of Alaska.

  12. Analysis of river planforms in the New Madrid region and possible relations to tectonic warping across the loess bluffs and within the meander belt of the Mississippi River

    SciTech Connect

    Johnson, K.A.; Mayer, L. . Dept. of Geology)

    1993-03-01

    Stream channel planforms measured from such streams as the Hatchie (H), L'Anguille (LA), St. Francis, White (W) and Little Red (LR) rivers provide a way to study influences of topographic warping between the loess bluffs that bound the Mississippi river valley. Planforms are analyzed using sinuosity, Richardson analysis, and pattern. Pattern changes include transitions from braided to meandering and meandering to straight. Sinuosities of the W and LR rivers show a transition from low sinuosity, [1.3, 1.4] to higher sinuosity [2.6, 2.8], over a short distance, as they cross the bluffs from the uplands to the Western Lowlands. On the east, the Hatchie changes from a braided to meandering pattern upon crossing the bluffs. Its sinuosity varies from a low of about 1.4 to a high of 2.2, coincident with a marsh area. The LA river flows on the west side of Crowley's Ridge and is paralleled by the St. Francis river on the east. These rivers, with very different drainage areas and sinuosities, show matching meander bends at similar wavelengths along Crowley's Ridge. The bends are about 10 km in 1/2 wavelength suggesting some extraordinary influence on pattern perpendicular to the ridge. Richardson analysis indicates that features with a 1/2 wavelength of 2 km may control several rivers' bending patterns. These features are analyzed to determine their spatial relations with one another.

  13. Pulsed Eruptions of the Sentinel Bluffs Member, Grande Ronde Basalt, Determined from Geochemical and Paleomagnetic Characterizations of Lava Flows

    NASA Astrophysics Data System (ADS)

    Sawlan, M. G.; Hagstrum, J. T.

    2015-12-01

    The identification of compositionally distinct lava flows is essential to determining the stratigraphy, number of lavas, and hence timing and frequency of eruptions in flood basalt provinces. Here, we address this issue using paired geochemical and paleomagnetic sampling of lavas comprising the Sentinel Bluffs Member (SB), the youngest member of the Grande Ronde Basalt (GRB). We develop the SB stratigraphy using geochemical characterizations of lavas based on ratios and mass-normalized abundances of immobile elements, together with an integrated stratigraphy of sections containing continuous exposures of multiple SB flows. Mass normalization is part of a mass analysis methodology that enables precise determinations of magmatic immobile element abundances of lavas variably enriched by alteration-generated mass loss (see Sawlan, M.G., 2013, Alteration, mass conservation, and magmatic compositions of lavas of the Columbia River flood basalt province: Insights from the Sentinel Bluffs Member, Grande Ronde Basalt: AGU Fall Meeting, V13F-2689). Within the SB chemical stratigraphy five chemical series, each of which includes three or four more precisely defined chemical groups, are recognized. Paleomagnetic directions, averaged by chemical series, show distinct differences between lavas of Series I (I=64.8°, D=351.2°, N=9, α95=3.8°), Series II-IV (I=56.5°, D=4.8°, N=29, α95=1.7°), and Series V (I=71.4°, D=326.0°, N=9, α95=4.6°). These differences in paleomagnetic directions of chemical series indicate SB eruptions occurred in pulsed eruptive episodes during which multiple, closely related, and geochemically distinct magmas erupted. Directions for Series II-IV lavas, near the geomagnetic dipole direction, are indistinguishable from one another (Series II: I=53.4°, D=2.0°, N=5, α95=4.4°; Series III: I=55.7°, D=5.6°, N=15, α95=1.8°; Series IV: I=59.6°, D=5.2°, N=9, α95=4.1°) and indicate that these lavas erupted either closely spaced in time or within

  14. Preliminary assessment of the health and environmental impacts of incinerating M55 rockets stored at Pine Bluff Arsenal, Lexington-Blue Grass Depot Activity, and/or Anniston Army Depot at Pine Bluff Arsenal

    SciTech Connect

    Boyette, J.A.; Breck, J.E.; Coleman, P.R.; Griffin, G.D.; Hillsman, E.L.; Johnson, P.E.; Kornegay, F.C.; Schweitzer, M.; Sigal, L.L.; Thomas, G.A.

    1986-03-01

    The purpose is to provide an assessment of the potential health and environmental impacts associated with converting and operating an incineration facility currently under construction at Pine Bluff Arsenal (PBA) in Arkansas. The plant is currently designed to dispose of the incapacitating agent BZ, and the converted plant would be designed to incinerate M55 rockets containing the nerve agent GB or VX. For the purposes of this study, the rockets to be incinerated at PBA are those currently stored at PBA and possibly those currently stored at Lexington-Blue Grass Depot Activity in Kentucky and/or at Anniston Army Depot in Alabama. The assessment considers impacts on air quality, ground and surface water, aquatic ecology, terrestrial ecology, human health, and cultural and socioeconomic resources at PBA and its host region. The assessment considers three basic scenarios during plant operations: normal operations, a minor spill of agent (i.e., the nerve-agent contents of one rocket being released to the biosphere), and an onsite transport accident (i.e., vaporization or aerosolization of the contents of two rockets and a spill of the remaining 13 rockets from an M55 rocket pallet) during disposal operations. For our assessment of accident impacts, we considered two separate sets of meteorological conditions: (1) conservative most likely and (2) worst-case.

  15. Prediction of turbulent recirculating flow field behind a V-shaped bluff body using a nonlinear low Reynolds number k-epsilon model

    NASA Astrophysics Data System (ADS)

    Gu, Zhan

    1998-09-01

    A new localized smoothing filter based on the least squares is proposed in this study. It has been found the use of an appropriate smoothing method is critical to the success of numerical prediction of separating flow problems with nonlinear turbulence models. The new smoothing filter effectively eliminated numerical fluctuations due to the nonlineality of the turbulence model and the higher order approximation. The efficiency of using this scheme is very attractive; less than 20% more CPU time is needed for the extra computation in simulations. Modification has been made to the nonlinear model to take into consideration of low Reynolds number effects. The two-dimensional turbulent recirculating flow field behind a V-shaped bluff body has been investigated numerically. Similar bluff bodies are used in combustion chambers for flame stabilization. The study helps to gain a comprehensive understanding of the mechanism of the flame stability and major factors that affect this stability, and thereby establishes a more reasonable physical model. The validation test of turbulent flow over a backward facing step shows that the modified nonlinear turbulence model significantly improved the overall prediction. Predicted results for both mean flow field and turbulence quantities agreed very well experimental results. The prediction error for the characteristic reattachment length has been reduced from 18% to 4% compared with the experimental data. The results of simulation of flow field behind the bluff body are also improved by using this model. The degree of improvement varies for different flow variables. Parametric investigation of the flow field by varying the shape and size of the bluff body is also performed. It has been found that the axial distributions of normalized reverse mass flow rate for different configurations are similar. The maximum reverse mass flow rate increases monotonically with the base height as well as with the included angle of the bluff body, but

  16. Large Eddy Simulations of forced ignition of a non-premixed bluff-body methane flame with Conditional Moment Closure

    SciTech Connect

    Triantafyllidis, A.; Mastorakos, E.; Eggels, R.L.G.M.

    2009-12-15

    Large Eddy Simulations (LES) of forced ignition of a bluff-body stabilised non-premixed methane flame using the Conditional Moment Closure (CMC) turbulent combustion model have been performed. The aim is to investigate the feasibility of the use of CMC/LES for ignition problems and to examine which, if any, of the characteristics already observed in related experiments could be predicted. A three-dimensional formulation of the CMC equation was used with simple and detailed chemical mechanisms, and sparks with different parameters (location, size) were used. It was found that the correct pattern of flame expansion and overall flame appearance were predicted with reasonable accuracy with both mechanisms, but the detailed mechanism resulted in expansion rates closer to the experiment. Moreover, the distribution of OH was predicted qualitatively accurately, with patches of high and low concentration in the recirculation zone during the ignition transient, consistent with experimental data. The location of the spark relative to the recirculation zone was found to determine the pattern of the flame propagation and the total time for the flame stabilisation. The size was also an important parameter, since it was found that the flame extinguishes when the spark is very small, in agreement with expectations from experiment. The stabilisation mechanism of the flame was dominated by the convection and sub-grid scale diffusion of hot combustion products from the recirculation zone to the cold gases that enter the burner, as revealed by analysis of the CMC equation. (author)

  17. Classification of gas-liquid flow patterns by the norm entropy of wavelet decomposed pressure fluctuations across a bluff body

    NASA Astrophysics Data System (ADS)

    Sun, Zhiqiang; Chen, Yanping; Gong, Hui

    2012-12-01

    Identification of gas-liquid flow patterns remains one of the paramount needs in multiphase flow metering. It is hardly possible to realize accurate measurement and control of parameters in a gas-liquid flow system without a clear understanding of its flow pattern. Here we explore the characterization of gas-liquid flow patterns using the norm entropy extracted from the wavelet decomposed pressure fluctuations across a bluff body. Experiments on air-water two-phase flow at ambient temperature and atmospheric pressure are carried out in the bubble, plug, slug and annular flow patterns. On the basis of the experimental results, two original flow-pattern maps are constructed: one is coordinated with the average norm entropy versus the total mass flow rate, and the other is the average norm entropy versus the volumetric void fraction. Verification tests demonstrate that the overall identification rates of the flow-pattern maps developed exceed 95%. This approach provides an effective and simple solution to the classification of gas-liquid flow patterns.

  18. Paleoenvironment of the Ogallala (Neogene) Formation in west-central Kansas

    SciTech Connect

    Twiss, P.C.; McCahon, T.J.; Oviatt, C.G. . Geology Dept.)

    1993-02-01

    At Lake Scott (Scott County) in west-central Kansas, the Ogallala Formation unconformably overlies the Niobrara Formation (Cretaceous) and forms the bluffs of the north-trending Ladder Creek valley. Two sections (Devil's Backbone, 23 m thick; Suicide Bluff, 45 m thick) contain fluvial sands that grade upward into probable eolian sands. The lower sections contain poorly cemented, moderately sorted, arkosic sand, some mud gravel, and poorly defined fluvial channels. In the lower part of Devil's Backbone, cross-bedded sand is capped by mud drapes. At Suicide Bluff, beds of cross-bedded and better sorted sand occur high in the section. Paleosols and secondary calcite and opal dominate the sections. Pedogenic calcretes with more than 52% CaCO[sub 3] are especially abundant and range up to morphologic Stage VI. The [delta][sup 13]C and [delta][sup 18]O in the calcretes range from [minus]4.8 to [minus]6.5 and [minus]8.2 to [minus]6.7 per mil (PDB), respectively. Opal-A has replaced most rhizoliths of the Ogallala. Silicified fossil seeds (Celtis sp., Biorbia sp.) and probable fossil mammal burrows also occur in the sections. Rhyolitic tephra, about 10 Ma, occurs 12 m below the calcrete caprock of Suicide Bluff. A massive layer of opal occurs about 8 m above the tephra and below a diatomaceous bed. Siliceous cement occurs throughout each section, possibly originating from opal phytoliths, tephra, and/or diatoms. These sections afford the potential for understanding the stratigraphic succession and paleoclimate during the late Miocene to possibly early Pliocene in the central High Plains region.

  19. Blowoff characteristics of bluff-body stabilized conical premixed flames with upstream spatial mixture gradients and velocity oscillations

    SciTech Connect

    Chaudhuri, Swetaprovo; Cetegen, Baki M.

    2008-06-15

    This experimental study concerns determination of blowoff equivalence ratios for lean premixed conical flames for different mixture approach velocities ranging from 5 to 16 m/s in the presence of spatial mixture gradients and upstream velocity modulation. Conical flames were anchored on a disk-shaped bluff body that was attached to a central rod in the burner nozzle. A combustible propane-air mixture flowed through a converging axisymmetric nozzle with a concentric insert, allowing radial mixture variation by tailoring the composition in the inner and outer parts of the nozzle. The radial mixture profiles were characterized near the location of the flame holder by laser Rayleigh light scattering. Additionally, a loudspeaker at the nozzle base allowed introduction of periodic velocity oscillations with an amplitude of 9% of the mean flow velocity up to a frequency of 350 Hz. The flame blowoff equivalence ratio was experimentally determined by continuously lowering the fuel flow rates and determining the flame detachment point from the flame holder. Flame detachment was detected by a rapid reduction of CH* emission from the flame base imaged by a photomultiplier detector. It was found that the flame blowoff is preceded by progressive narrowing of the flame cone for the case of higher inner jet equivalence ratios. In this case, the fuel-lean outer flow cannot sustain combustion, and clearly this is not a good way of operating a combustor. Nevertheless, the overall blowoff equivalence ratio is reduced by inner stream fuel enrichment. A possible explanation for this behavior is given based on the radial extent of the variable-equivalence-ratio mixture burning near the flame stabilization region. Fuel enrichment in the outer flow was found to have no effect on blowoff as compared to the case of uniform mixture. The results were similar for the whole range of mean flow velocities and upstream excitation frequencies. (author)

  20. Two-stage growth of the Late Miocene Minna Bluff Volcanic Complex, Ross Embayment, Antarctica: implications for ice-sheet and volcanic histories

    NASA Astrophysics Data System (ADS)

    Wilch, T. I.; McIntosh, W. C.; Panter, K. S.; Dunbar, N. W.; Smellie, J.; Fargo, A. J.; Ross, J. I.; Antibus, J. V.; Scanlan, M. K.

    2011-12-01

    Minna Bluff, a 45km long, 5km wide Late Miocene alkaline volcanic peninsula that extends SE into the Ross Ice Shelf, is a major obstruction to ice flow from the south into the McMurdo Sound region. Interpretations of the abundant paleoclimate and glacial history archives, including the ANDRILL records, need to account for the effects of paleogeography on past ice-flow configurations and sediment transport. Mapping and 40Ar/39Ar dating of volcanic sequences indicate that Minna Bluff was constructed between 12 and 4 Ma. The volcanic complex first emerged as an isolated island in the Ross Sea at about 12 Ma. The edifice, here named Minna Hook Island, was constructed between 12 and 8 Ma. During this first stage of growth, regional ice was able to flow through a ~40 km gap between the island and mainland. The second stage of volcanism built the main arm of Minna Bluff, now called McIntosh Cliffs, between 8 and 4 Ma. The second stage resulted in the eruption of exclusively subaerial cinder cones and lava flows. By approximately 5 Ma the peninsula had fully emerged above sea level, fully obstructing ice flow. Evidence for volcano-ice interaction is common in Minna Hook stratigraphic sequences. Well exposed cliff sections exhibit alternations between rocks erupted in subaerial and subaqueous conditions; these sequences are interpreted to represent syneruptive interactions between lava flows and glacial ice and provide evidence for periodic glaciations between 12 and 8 Ma. The lack of coherent horizontal passage zones between subglacial and subaerial lithofacies and the alternating nature of the deposits suggest that the eruptions did not occur in a large stable ice sheet but instead occurred in a more ephemeral local ice cap or rapidly drained ice sheet. At least two widespread, undulating glacial unconformities mantled by glacial and fluvial sediments are exposed near the base of the Minna Hook sequences. These unconformities record broad scale Antarctic Ice Sheet events

  1. Suppression of vortex shedding from bluff bodies with a fixed wavy separation line

    NASA Astrophysics Data System (ADS)

    Darekar, R. M.; Sherwin, S. J.

    1998-11-01

    A numerical investigation has been performed of flow past rectangular cylinders with a three dimensional geometric perturbation on the front stagnation face which results in the suppression of the von Kármán shedding frequency. The perturbation is applied in the form of a sinusoidal spanwise waviness as experimentally studied by Bearman and Owen. The computations were performed using a spectral/hp element solver, Nektar at a Reynolds number of Re=100 and are in good agreement with experiments. After a transient time period where shedding is observed the near wake stabilises to a near time-independent state. Once vortex shedding is suppressed, the detached shear layer from the upper and lower fixed separations points is observed to have a spanwise form which has a maximum displacement at the valleys of the geometry and a minimum displacement at the peaks. The vortex suppression is associated with a drag reduction and corresponding increase in base pressure as compared with the straight cylinder of about 14% at Re=100. Furthermore, the computations clearly show two counter-rotating cells in the near wake. Using the coherent structure identification proposed by Jeong and Hussain, the vortical structure of the near wake has been extracted and a distorted vortex ring is observed in the near wake connecting the upper and lower shear layers. Current investigation are focused towards understanding the stabilising nature and formation of the vortical structures.

  2. A petrographic, geochemical and isotopic (O, H, C and Sr) investigation of secondary minerals in volcaniclastic rocks at Minna Bluff, Antarctica: Petrogenesis of alteration and implications for paleoenvironmental conditions

    NASA Astrophysics Data System (ADS)

    Antibus, J. V.; Panter, K. S.; Wilch, T. I.; Dunbar, N. W.; McIntosh, W. C.; Blusztajn, J.; Tripati, A. K.; Bindeman, I. N.

    2012-12-01

    exchange between meteoric water (ice and snow) and glass-rich volcaniclastics during or soon after the formation of each deposit. Changing conditions between anoxic and oxic environments are indicated by variations in the intensity of luminescence and Fe2+/Mn ratios measured in zoned carbonates. Secondary minerals were formed at elevated temperatures based on the stability of the zeolites (10°-99°C) and refined further using estimates from carbonate 13C-18O paleothermometry (5°-43°C). Evaporative distillation, possibly from steam vents, can explain enriched 18O compositions of some Mg-rich carbonates and chalcedony. The results may provide a record of climate variability during the growth of Minna Bluff. Using the estimated temperatures of formation and published fractionation factors, the δ18O of meteoric water in equilibrium with carbonates is calculated. In conjunction with estimates for the timing of alteration constrained by lavas dated above and below each deposit, these data reveal a broad shift from lighter (-24‰) to heavier (-16‰) values between ~11 and ~8.5 Ma, consistent with a period of climate warming. These findings are independently corroborated by the interpretation of Late Miocene sedimentary sequences recovered from the nearby AND-1B core.

  3. Computational fluid dynamic studies of certain ducted bluff-body flowfields relevant to turbojet combustors. Volume 2: Time-averaged flowfield predictions for a proposed centerbody combustor

    NASA Astrophysics Data System (ADS)

    Raju, M. S.; Krishnamurthy, L.

    1986-07-01

    The near-wake region in a ducted bluff-body combustor was investigated by finite-difference computations. The numerical predictions are based upon the time-independent, Reynolds-averaged Navier-Stokes equations and the k-epsilon turbulence model. The steady-state calculations address both nonreacting and reacting flowfields in a novel configuration to more realistically simulate some of the essential features of the primary zone of a gas turbine combustion chamber. This configuration is characterized by turbulent mixing and combustion in the recirculating near-wake region downstream of an axisymmetric bluff body due to two annular air streams--an outer swirl-free flow and an inner swirling flow--and a central fuel jet. The latter contains propane for reacting flows and carbon dioxide for nonreacting flows. In view of the large number of geometrical and flow parameters involved, the reported results are concerned with only a limited parametric examination with the major emphasis being on nonreacting flows. Questions addressed for a particular set of geometric parameters include the effects of variation of mass flow rates in all three streams and the influence of swirl in the middle stream. Reacting computations investigate the influence of swirl on combustion, as well as that of combustion on the flowfield.

  4. Interglacial Extension of the Boreal Forest Limit in the Noatak Valley, Northwest Alaska: Evidence from an Exhumed River-Cut Bluff and Debris Apron

    USGS Publications Warehouse

    Edwards, M.E.; Hamilton, T.D.; Elias, S.A.; Bigelow, N.H.; Krumhardt, A.P.

    2003-01-01

    Numerous exposures of Pleistocene sediments occur in the Noatak basin, which extends for 130 km along the Noatak River in northwestern Alaska. Nk-37, an extensive bluff exposure near the west end of the basin, contains a record of at least three glacial advances separated by interglacial and interstadial deposits. An ancient river-cut bluff and associated debris apron is exposed in profile through the central part of Nk-37. The debris apron contains a rich biotic record and represents part of an interglaciation that is probably assignable to marine-isotope stage 5. Pollen spectra from the lower part of the debris apron closely resemble modern samples taken from the Noatak floodplain in spruce gallery forest, and macrofossils of spruce are also present at this level. Fossil bark beetles and carpenter ants occur higher in the debris apron. Mutual Climatic Range (MCR) estimates from the fossil beetles suggest temperatures similar to or warmer than today. Together, these fossils indicate the presence of an interglacial spruce forest in the western part of the Noatak Basin, which lies about 80 km upstream of the modern limit of spruce forest.

  5. Aerodynamics of the flying snake Chrysopelea paradisi: how a bluff body cross-sectional shape contributes to gliding performance.

    PubMed

    Holden, Daniel; Socha, John J; Cardwell, Nicholas D; Vlachos, Pavlos P

    2014-02-01

    A prominent feature of gliding flight in snakes of the genus Chrysopelea is the unique cross-sectional shape of the body, which acts as the lifting surface in the absence of wings. When gliding, the flying snake Chrysopelea paradisi morphs its circular cross-section into a triangular shape by splaying its ribs and flattening its body in the dorsoventral axis, forming a geometry with fore-aft symmetry and a thick profile. Here, we aimed to understand the aerodynamic properties of the snake's cross-sectional shape to determine its contribution to gliding at low Reynolds numbers. We used a straight physical model in a water tunnel to isolate the effects of 2D shape, analogously to studying the profile of an airfoil of a more typical flyer. Force measurements and time-resolved (TR) digital particle image velocimetry (DPIV) were used to determine lift and drag coefficients, wake dynamics and vortex-shedding characteristics of the shape across a behaviorally relevant range of Reynolds numbers and angles of attack. The snake's cross-sectional shape produced a maximum lift coefficient of 1.9 and maximum lift-to-drag ratio of 2.7, maintained increases in lift up to 35 deg, and exhibited two distinctly different vortex-shedding modes. Within the measured Reynolds number regime (Re=3000-15,000), this geometry generated significantly larger maximum lift coefficients than many other shapes including bluff bodies, thick airfoils, symmetric airfoils and circular arc airfoils. In addition, the snake's shape exhibited a gentle stall region that maintained relatively high lift production even up to the highest angle of attack tested (60 deg). Overall, the cross-sectional geometry of the flying snake demonstrated robust aerodynamic behavior by maintaining significant lift production and near-maximum lift-to-drag ratios over a wide range of parameters. These aerodynamic characteristics help to explain how the snake can glide at steep angles and over a wide range of angles of attack

  6. Experimental study of compressibility effects on entrainment and mixing in supersonic planar turbulent bluff-body wakes

    NASA Astrophysics Data System (ADS)

    Nakagawa, Masaki

    2001-07-01

    Understanding effects of compressibility on the entrainment and mixing properties of supersonic turbulent shear flows is a key to successful development of the next generation of high-speed airbreathing propulsion systems. Previous studies have focused largely on supersonic mixing layers, and have shown dramatic reductions in the entrainment and mixing rates with increasing compressibility which has been widely believed to be a generic effect of compressibility in supersonic turbulent shear flows. The present dissertation reports results from an experimental investigation of entrainment and mixing in supersonic, planar, turbulent, bluff-body wakes to clarify the generic effects of compressibility in turbulent shear flows. The experimental techniques, including conventional pressure measurements, shadowgraph and planar laser Mie scattering (PLMS) visualizations, and particle image velocimetry (PIV), were used to study instantaneous and mean velocity fields, scaling properties, turbulence statistics, and large-scale structure in instantaneous and phase-averaged vorticity fields over a range of relative Mach numbers. These were compared with corresponding results from incompressible wakes and from supersonic mixing layers. Results indicate that the classical vortex street-like large scale structure of incompressible planar turbulent wakes is recovered in supersonic wakes where the local relative Mach number Mr(x) has decreased to sufficiently small values, but no comparable large-scale organized structure is evident where the relative Mach number is large. Moreover, at downstream locations where Mr(x) is large, a reduction in the growth rate of the flow is observed due to compressibility, but this reduction is significantly smaller than that reported from studies of supersonic mixing layers. Results also show that the wake undergoes a self-induced forcing where it passes through reflected expansion waves produced by the wake generator. This local forcing alters the

  7. Water-resources appraisal of the Camp Swift lignite area, central Texas

    USGS Publications Warehouse

    Gaylord, J.L.; Slade, R.M.; Ruiz, L.M.; Welborn, C.T.; Baker, E.T.

    1985-01-01

    The Camp Swift area, Texas was studied to describe the hydrogeology and to provide baseline data of the groundwater and surface water resources that would be affected by the strip mining of lignite. The investigation was centered on the 18-square mile Camp Swift Military Reservation where a reported 80 to 100 million short tons of commercially mineable lignite occurs within 200 feet of the land surface. Groundwater data showed that water levels in observation wells changed only slightly and that the water quality in the Calvert Bluff Formation, which contains the lignite, and in the Simsboro Formation, which is the major aquifer beneath the Calvert Bluff, is suitable for most uses. Big Sandy Creek, which crosses Camp Swift generally has a base flow of less than 0.5 cu ft/sec and infrequently is dry. Dogwood Creek, which originates on Camp Swift, usually is dry. The flow of both streams changes rapidly in response to rainfall in the watersheds. The quality of the water in both streams generally is suitable for most uses. A lithologic examination of 255 feet of cored section that represents the overburden and the lignite showed cyclic layering of fine sand, silt, clay, and lignite. Chemical analyses indicate that the pyritic sulfur concentration is small but variable. (USGS)

  8. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Annual report, December 1, 1992--December 31, 1993

    SciTech Connect

    Sharma, G.D.

    1994-01-01

    The shallow Cretaceous sands of the Schrader Bluff Reservoir occur between depths of 4,000 and 4,800 feet below surface and are estimated to contain up to 1.5 billion barrels of oil in place. The field is currently under production by primary depletion. Initial production indicated that primary recovery will fall short of earlier estimates and waterflooding will have to be employed much earlier than expected. A large portion of the oil-in-place thus would still be left behind in this reservoir after primary and secondary recovery methods have been applied. Enhanced oil recovery (EOR) techniques will be needed to recover the additional portion of remaining oil in this huge reservoir and to add significant additional reserves. Slim tube displacement studies, PVT data and asphaltene precipitation studies are needed for Schrader Bluff heavy oil to define possible hydrocarbon solvent suitable for miscible solvent slug displacement process. Such studies are essential because the API gravity of the crude in Schrader Bluff reservoir varies significantly from well to well. Coreflood experiments are also needed to determine effect of solvent slug size, WAG ratio and solvent composition on the oil recovery and solvent breakthrough. A compositional reservoir simulation study will be conducted later to evaluate the complete performance of the hydrocarbon solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir. This report contains the following: reservoir description; slim tube displacement studies; and coreflood experiments.

  9. Vortex Formation in Shallow Flows

    NASA Astrophysics Data System (ADS)

    Rockwell, Donald

    2006-11-01

    Vortical structures having a scale much larger than the depth of the flow, which arise in bluff body wakes, jets, and mixing layers generated in shallow layers, show distinctive features due to the influence of bed friction. Cinema techniques of high-image-density particle image velocimetry are employed to characterize quasi-two-dimensional and three-dimensional aspects of the vortex development in terms of: patterns of vorticity; flow topology involving definition of critical points; and global spectral and cross-spectral analyses, based on simultaneous time records at thousands of grid points of the cinema imaging. Taken together, these representations lead to an understanding of the relationship between coherent vortex development and unsteadiness along the bed and, furthermore, provide a basis for exploration of concepts generic to separated shear layers in shallow flows. These concepts include: suppression of a primary mode of vortex formation due to bed friction and emergence of another mode; resonant coupling between a gravity wave of the shallow layer and vortex formation, leading to large-scale vortices; and passive and active (open loop) control, which can either retard or enhance the onset of vortex formation. These studies suggest opportunities for further investigation on both experimental and numerical fronts. Collaboration with Haojun Fu, Alis Ekmekci, Jung-Chang Lin, and Muammer Ozgoren is gratefully acknowledged.

  10. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. Annual report, January 1, 1994--December 31, 1994

    SciTech Connect

    Sharma, G.D.

    1995-07-01

    Alaska is the second largest oil producing state in the nation and currently contributes nearly 24% of the nations oil production. It is imperative that Alaskan heavy oil fields be brought into production. Schrader Bluff reservoir, located in the Milne Point Unit, which is part of the heavy oil field known as West Sak is estimated to contain 1.5 billion barrels of (14 to 21 degree API) oil-in-place. The field is currently under production by primary depletion. The eventual implementation of enhanced oil recovery (EOR) techniques will be vital for the recovery of additional oil from this reservoir. The availability of hydrocarbon gases (solvents) on the Alaska North Slope make the hydrocarbon miscible solvent injection process an important consideration for the EOR project in Schrader Bluff reservoir. Since Schrader Bluff oil is heavy and viscous, a water-alternating-gas (WAG) type of process for oil recovery is appropriate since such a process tends to derive synergetic benefits from both water injection (which provides mobility control and improvement in sweep efficiency) and miscible gas injection (which provides improved displacement efficiency). A miscible solvent slug injection process rather than continuous solvent injection is considered appropriate. Slim tube displacement studies, PVT data and asphaltene precipitation studies are needed for Schrader bluff heavy oil to define possible hydrocarbon solvent suitable for miscible solvent slug displacement process. Coreflood experiments are also needed to determine the effect of solvent slug size, WAG ratio and solvent composition on the recovery and solvent breakthrough. A compositional reservoir simulation study will be conducted later to evaluate the complete performance of the hydrocarbon solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir.

  11. The Knowledge Bluff

    ERIC Educational Resources Information Center

    Vanderburg, Willem H.

    2007-01-01

    Our knowledge "system" is built up from disciplines and specialties as its components, which are "wired" by patterns of collaboration that constitute its organization. The intellectual autonomy of these components prevents this knowledge system from adequately accounting for what we have gradually discovered during the past 50 years: In human…

  12. High altitude flight test of a disk gap band parachute deployed behind a bluff body at a Mach number of 2.69

    NASA Technical Reports Server (NTRS)

    Eckstrom, C.; Branscome, D. R.

    1972-01-01

    A flight test was conducted with a 55-foot diameter disk-gap-band parachute located at a trailing distance of 4.4 forebody diameters behind a 15-foot diameter bluff-body planetary entry aeroshell and attached instrumented payload. At the time of parachute deployment the aeroshell-payload combination was oscillating through an angle-of-attack range of plus or minus 40 deg. Continued oscillatory motion of the aeroshell-payload combination and similar motion of the parachute caused rapid changes in parachute shape and loading which resulted in extensive cloth damage in the band and outer disk-edge areas of the parachute canopy. During steady-state descent the damage parachute provided an effective-drag coefficient of about 0.33 which was about 60 percent of that expected.

  13. Hydrology, Water Quality, and Causes of Changes in Vegetation in the Vicinity of the Spring Bluff Nature Preserve, Lake County, Illinois, May 2007-August 2008

    USGS Publications Warehouse

    Kay, Robert T.; Miner, James J.; Maurer, Debbie A.; Knight, Charles W.

    2010-01-01

    Agriculture and urbanization have altered the hydrology and water quality of the coastal wetland complex along the shore of Lake Michigan at the Spring Bluff Nature Preserve and Illinois Beach State Park in northeastern Lake County, Ill., and the adjacent Chiwaukee Prairie State Natural Area in southeastern Wisconsin. Culverts, roads, ditches, and berms installed within the wetland complex have altered the natural directions of surface-water flow and likely have increased the natural hydroperiod in the Spring Bluff Nature Preserve and decreased it in the northern part of the Illinois Beach State Park. Relative to presettlement conditions, surface-water runoff into the wetlands likely is greater in quantity and higher in concentrations of several constituents, including chloride, nitrate, phosphorous, and suspended sediment. These constituent concentrations are affected by a variety of factors, including the amount of agricultural and urban land use in the watersheds. Hydrologic, chemical, and biologic processes within the wetland communities reduce the concentrations of these constituents in surface water before the water discharges to Lake Michigan by as much as 75 percent for chloride, 85 percent for nitrate, 66 percent for phosphorous, and more than an order of magnitude for suspended sediment. However, concentrations of phosphorous and suspended sediment in surface water increased within parts of the wetland complex. Given these changes, the floristic quality of these wetlands has been altered from the historic condition. Specifically, Typha spp. and Phragmites australis occur in greater numbers and over a larger area than in the past. The spread of Typha spp. and Phragmites australis appears to be enhanced by anthropogenic alterations within the wetland complex, such as increased water levels and duration of inundation and, possibly, increases in the total concentration of dissolved constituents in water.

  14. Forced sea-level change in a forearc basin related to subduction of a spreading ridge: the Fossil Bluff Group (Jurassic-Cretaceous), Alexander Island, Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Macdonald, David

    2015-04-01

    During the Mesozoic, the Antarctic Peninsula was the site of an active volcanic arc related to the eastwards subduction of proto-Pacific oceanic crust. Alexander Island is the largest of the many islands that lie on the western (fore-arc) side of the Antarctic Peninsula; it forms one of the best-exposed ancient fore-arcs in the world. The pre-Tertiary rocks can be divided into two main units. The LeMay Group (Jurassic-Tertiary) forms the structural basement to Alexander Island and comprises greenschist-facies metasedimentary rocks. It is interpreted as a Mesozoic accretionary prism. The Fossil Bluff Group unconformably overlies and is faulted against the LeMay Group; it represents the sedimentary fill of a coeval fore-arc basin. Subduction ceased due to a series of Cenozoic ridge-trench collisions which began off Alexander Island at 50 Ma and got progressively younger to the north. However, the approach of the ridge can be inferred from the Mesozoic deposits of the Fossil Bluff Group (Jurassic-Cretaceous) in Alexander Island. In this paper, I will show that the ocean floor being subducted became progressively shallower through Jurassic and Cretaceous time (by at least 1,000 m). The result in the forearc basin was a sudden shallowing in water depths from at least 1,000 m at 125 Ma, to emergent at 100 Ma. This forced shallowing ended sedimentation in the basin and resulted in considerable topography on Alexander Island that persists to the present day.

  15. Superfund Record of Decision (EPA Region 7): Mid-America Tanning site, Sergeant bBluff, IA. (First remedial action), September 1991

    SciTech Connect

    Not Available

    1991-09-24

    The 98.7-acre Mid-America Tanning site is a former leather tannery in Sergeant Bluff, Woodbury County, Iowa. Surrounding land use is mixed industrial and agricultural. A portion of the site is bordered by Oxbow Lake and lies within the 100-year floodplain. The Missouri River is approximately 1.5 miles to the southwest of the site and receives discharges from Oxbow Lake. The facility began onsite processing of animal hides in 1970. In 1980, the State confirmed the onsite burial of chromium-containing sludge in trenches, and the company was cited for permit violations. A 1985 EPA investigation identified excessive chromium contamination in onsite soil, sediment, and ground water. In 1990, EPA conducted a removal action that included excavating and consolidating onsite 1,290 cubic yards of sludge from the trench disposal area. The Record of Decision (ROD) addresses the contaminated soil, impoundment sediment and water, and the excavated trench material. A future ROD will address onsite ground water contamination. The primary contaminant of concern affecting the soil, sediment, debris, sludge, and surface water are metals including chromium and lead. The selected remedial action for the site is included.

  16. Multispectral remote sensing of the Gosses Bluff impact crater, central Australia (N.T.) by using Landsat-TM and ERS-1 data

    NASA Astrophysics Data System (ADS)

    Prinz, Torsten

    Remote sensing techniques offer a unique chance to analyse and to map planetary impact craters in a relatively short time and at low cost. In the past, studies were mainly restricted to the search for possible impact sites (e.g. Earth) or for age determinations (crater statistics). On the basis of Landsat-TM 5 and ERS-1 data the lithological and structural characteristics of the complex Gosses Bluff impact crater (Australia) has been analysed in order to obtain reasonable lithological classification approaches. The fundamental statistical selection rule for pure colour composites of original TM-data was the calculation of the optimum index factor (OIF), or for hybrid colour composites (e.g. a combination of a original TM-band with a principal component and a ratio) using the widest statistical variance for each dataset. Additional spectral measurements were carried out for each representative rock unit of the crater specific zones in order to estimate the quality of supervised maximum-likelihood computer classifications for geological mapping. Complementary ERS-1 altimetric data were utilized to study the resulting crater morphology as an expression of the displacement effects and some structural features of the target caused by the cratering process (e.g. diameter, fracture pattern, ejecta displacement, etc.).

  17. PDF model based on Langevin equation for polydispersed two-phase flows applied to a bluff-body gas-solid flow

    NASA Astrophysics Data System (ADS)

    Minier, Jean-Pierre; Peirano, Eric; Chibbaro, Sergio

    2004-07-01

    The aim of the paper is to discuss the main characteristics of a complete theoretical and numerical model for turbulent polydispersed two-phase flows, pointing out some specific issues. The theoretical details of the model have already been presented [Minier and Peirano, Phys. Rep. 352, 1 (2001)]. Consequently, the present work is mainly focused on complementary aspects that are often overlooked and that require particular attention. In particular, the following points are analyzed: the necessity to add an extra term in the equation for the velocity of the fluid seen in the case of two-way coupling, the theoretical and numerical evaluations of particle averages and the fulfillment of the particle mass-continuity constraint. The theoretical model is developed within the probability density function (PDF) formalism. The important physical choice of the state vector variables is first discussed and the model is then expressed as a stochastic differential equation written in continuous time (Langevin equations) for the velocity of the fluid seen. The interests and limitations of Langevin equations, compared to the single-phase case, are reviewed. From the numerical point of view, the model corresponds to a hybrid Eulerian/Lagrangian approach where the fluid and particle phases are simulated by different methods. Important aspects of the Monte Carlo particle/mesh numerical method are emphasized. Finally, the complete model is validated and its performance is assessed by simulating a bluff-body case with an important recirculation zone and in which two-way coupling is noticeable.

  18. Invertebrate fossils (Insecta: Trichoptera, Diptera, Coleoptera) from the Pleistocene Scarborough Formation at Toronto, Ontario, and their paleoenvironmental significance

    NASA Astrophysics Data System (ADS)

    Williams, Nancy E.; Westgate, John A.; Williams, D. Dudley; Morgan, Anne; Morgan, Alan V.

    1981-09-01

    Larval caddisfly, chironomid, and beetle remains have been recovered from the Pleistocene Scarborough Formation in the Toronto region of southern Ontario. Three stratigraphic levels were sampled at the northeastern end of the Scarborough Bluffs; the youngest horizon yielded 16 chironomid taxa, 33 caddisfly taxa, and 28 beetle taxa, whereas the two older levels yielded somewhat less diverse assemblages. Only one taxon in each of the caddisfly and chironomid groups was identified from the presumed correlative beds at Woodbridge, Ontario, but numerous beetle fragments were recovered, several of which have been specifically identified and match species found previously in the upper part of the Scarborough Formation. The youngest sampled assemblage in the Scarborough Formation at the northeastern end of the Scarborough Bluffs is interpreted as indicating cool climatic conditions in a boreal forest environment, given the present-day distributions and feeding habits of these river, lake, and terrestrial taxa. The mean July temperature at this time was probably about 15°C, as compared to the present-day value of 20.5°C. The forest was poorer in deciduous species during deposition of the older part of the formation as preserved here. These results agree well with previous interpretations based on plant remains. We suggest that both aquatic and terrestrial insects are good indicators of macroclimate.

  19. Preliminary Image Map of the 2007 Ammo Fire Perimeter, San Onofre Bluff Quadrangle, San Diego County, California

    USGS Publications Warehouse

    Clark, Perry S.; Scratch, Wendy S.; Bias, Gaylord W.; Stander, Gregory B.; Sexton, Jenne L.; Krawczak, Bridgette J.

    2008-01-01

    In the fall of 2007, wildfires burned out of control in southern California. The extent of these fires encompassed large geographic areas that included a variety of landscapes from urban to wilderness. The U.S. Geological Survey National Geospatial Technical Operations Center (NGTOC) is currently (2008) developing a quadrangle-based 1:24,000-scale image map product. One of the concepts behind the image map product is to provide an updated map in electronic format to assist with emergency response. This image map is one of 55 preliminary image map quadrangles covering the areas burned by the southern California wildfires. Each map is a layered, geo-registered Portable Document Format (.pdf) file. For more information about the layered geo-registered .pdf, see the readme file (http://pubs.usgs.gov/of/2008/1029/downloads/CA_Agua_Dulce_of2008-1029_README.txt). To view the areas affected and the quadrangles mapped in this preliminary project, see the map index (http://pubs.usgs.gov/of/2008/1029/downloads/CA_of2008_1029-1083_index.pdf) provided with this report.

  20. Shatter Complex Formation in the Twin Craters Lava Flow, Zuni-Bandera Field, New Mexico

    NASA Astrophysics Data System (ADS)

    von Meerscheidt, H. C.; Bleacher, J. E.; Brand, B. D.; deWet, A.; Samuels, R.; Hamilton, C.; Garry, W. B.; Bandfield, J. L.

    2013-12-01

    . Prominent ';a';a channels travel around the bluff, leaving a 'wake' of uncovered ground on the downstream side. We interpret this shatter area to have been a branching tube network within an active sheet. The limestone bluff acted as an obstacle that caused a backup of lava within the tubes, driving episodes of shattering. The mounds likely represent earlier solidified sections between active, possibly braided, tube branches, which remained as mounds within the shatter area after the adjacent crust subsided. When lava broke out from the pressurized sheet-like lobe, it formed the ';a';a channels. This section of the flow field is interpreted using inferences from shatter ring formation, but is perhaps better termed a shatter sheet or shatter complex. This study has implications for understanding lava flow dynamics at constriction points, as well as the evolution and morphology of shatter rings.

  1. Habitat quality and recruitment success of cui-ui in the Truckee River downstream of Marble Bluff Dam, Pyramid Lake, Nevada

    USGS Publications Warehouse

    Scoppettone, G. Gary; Rissler, Peter H.; Salgado, J. Antonio; Harry, Beverly

    2013-01-01

    We compared cui-ui (Chasmistes cujus) recruitment from two reaches of the Truckee River with histories of severe erosional downcutting caused by a decline in Pyramid Lake surface elevation. In 1975, Marble Bluff Dam (MBD) was constructed 5 kilometers upstream of the extant mouth of the Truckee River to stabilize the upstream reach of the river; the downstream reach of the river remained unstable and consequently unsuitable for cui-ui recruitment. By the early 2000s, there was a decrease in the Truckee River’s slope from MBD to Pyramid Lake after a series of wet years in the 1990s. This was followed by changes in river morphology and erosion abatement. These changes led to the question as to cui-ui recruitment potential in the Truckee River downstream of MBD. In 2012, more than 7,000 cui-ui spawners were passed upstream of MBD, although an indeterminate number of cui-ui spawned downstream of MBD. In this study, we compared cui-ui recruitment upstream and downstream of MBD during a Truckee River low-flow year (2012). Cui-ui larvae emigration to Pyramid Lake began earlier and ended later downstream of MBD. A greater number of cui-ui larvae was produced downstream of MBD than upstream. This also was true for native Tahoe sucker (Catostomus tahoensis) and Lahontan redside (Richardsonius egregius). The improved Truckee River stability downstream of MBD and concomitant cui-ui recruitment success is attributed to a rise in Pyramid Lake's surface elevation. A decline in lake elevation may lead to a shift in stream morphology and substrate composition to the detriment of cui-ui reproductive success as well as the reproductive success of other native fishes.

  2. Integrating Near-Real Time Hydrologic-Response Monitoring and Modeling for Improved Assessments of Slope Stability Along the Coastal Bluffs of the Puget Sound Rail Corridor, Washington State

    NASA Astrophysics Data System (ADS)

    Mirus, B. B.; Baum, R. L.; Stark, B.; Smith, J. B.; Michel, A.

    2015-12-01

    Previous USGS research on landslide potential in hillside areas and coastal bluffs around Puget Sound, WA, has identified rainfall thresholds and antecedent moisture conditions that correlate with heightened probability of shallow landslides. However, physically based assessments of temporal and spatial variability in landslide potential require improved quantitative characterization of the hydrologic controls on landslide initiation in heterogeneous geologic materials. Here we present preliminary steps towards integrating monitoring of hydrologic response with physically based numerical modeling to inform the development of a landslide warning system for a railway corridor along the eastern shore of Puget Sound. We instrumented two sites along the steep coastal bluffs - one active landslide and one currently stable slope with the potential for failure - to monitor rainfall, soil-moisture, and pore-pressure dynamics in near-real time. We applied a distributed model of variably saturated subsurface flow for each site, with heterogeneous hydraulic-property distributions based on our detailed site characterization of the surficial colluvium and the underlying glacial-lacustrine deposits that form the bluffs. We calibrated the model with observed volumetric water content and matric potential time series, then used simulated pore pressures from the calibrated model to calculate the suction stress and the corresponding distribution of the factor of safety against landsliding with the infinite slope approximation. Although the utility of the model is limited by uncertainty in the deeper groundwater flow system, the continuous simulation of near-surface hydrologic response can help to quantify the temporal variations in the potential for shallow slope failures at the two sites. Thus the integration of near-real time monitoring and physically based modeling contributes a useful tool towards mitigating hazards along the Puget Sound railway corridor.

  3. Quaternary geology of the Duck Hawk Bluffs, southwest Banks Island, Arctic Canada: a re-investigation of a critical terrestrial type locality for glacial and interglacial events bordering the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Evans, David J. A.; England, John H.; La Farge, Catherine; Coulthard, Roy D.; Lakeman, Thomas R.; Vaughan, Jessica M.

    2014-05-01

    Duck Hawk Bluffs, southwest Banks Island, is a primary section (8 km long and 60 m high) in the western Canadian Arctic Archipelago exposing a long record of Quaternary sedimentation adjacent to the Arctic Ocean. A reinvestigation of Duck Hawk Bluffs demonstrates that it is a previously unrecognized thrust-block moraine emplaced from the northeast by Laurentide ice. Previous stratigraphic models of Duck Hawk Bluffs reported a basal unit of preglacial fluvial sand and gravel (Beaufort Fm, forested Arctic), overlain by a succession of three glaciations and at least two interglacials. Our observations dismiss the occurrence of preglacial sediments and amalgamate the entire record into three glacial intervals and one prominent interglacial. The first glacigenic sedimentation is recorded by an ice-contact sandur containing redeposited allochthonous organics previously assigned to the Beaufort Fm. This is overlain by fine-grained sediments with ice wedge pseudomorphs and well-preserved bryophyte assemblages corresponding to an interglacial environment similar to modern. The second glacial interval is recorded by ice-proximal mass flows and marine rhythmites that were glacitectonized when Laurentide ice overrode the site from Amundsen Gulf to the south. Sediments of this interval have been reported to be magnetically reversed (>780 ka). The third interval of glacigenic sedimentation includes glacifluvial sand and gravel recording the arrival of Laurentide ice that overrode the site from the northeast (island interior) depositing a glacitectonite and constructing the thrust block moraine that comprises Duck Hawk Bluffs. Sediments of this interval have been reported to be magnetically normal (<780 ka). The glacitectonite contains a highly deformed melange of pre-existing sediments that were previously assigned to several formally named, marine and interglacial deposits resting in an undeformed sequence. In contrast, the tectonism associated with the thrust block moraine

  4. Sequential palynostratigraphy of the Queen City and Weches formations (Middle Eocene Claiborne Group), southeast central Texas

    SciTech Connect

    Elsik, W.C. )

    1993-02-01

    Palynomorph sequences of several orders of magnitude were found in the Queen City and Weches formations respectively at Six Mile and Burleson bluffs on the Brazos River, Milam and Burleson counties, Texas. The long term development of the subtropical to tropical Claibornian palynoflora included Engelhardtia spp., Friedrichipollis claibornensis, Nudopollis terminalis, Pollenites laesius and Symplocoipollenites spp. Shorter term fluctuations in sea level were reflected by common herbaceous pollen in the Queen City, and common mangrove pollen in the Weches. Paleoenvironments were marginally to fully marine; dinocysts occurred throughout. The Wetzeliella group of dinocysts were present only in the Queen City at Six Mile Bluff. Late Paleocene to Early Eocene pollen, and Early Middle Eocene pollen with last effective occurrences near the Queen City and Weches boundary included Aesculiidites circumstriatus, Annona foveoreticulata and a new species of Platycarya. Five short term warmer-cooler couplet events were represented by successive abundance peaks of Juglandaceae followed by Ulmus; Alnus supports the three upper Ulmus peaks. One deep water event was recorded by an abundance of fresh water Pediastrum at the Queen City and Weches boundary. That boundary event was bracketed by two of the Alnus and Ulmus peaks.

  5. Vadose-zone recharge and weathering in an Eocene sand deposit, East Texas, U.S.A.

    NASA Astrophysics Data System (ADS)

    Dutton, A. R.

    1990-03-01

    Weathering of terrigenous sand in the vadose zone of the Eocene Calvert Bluff Formation in Freestone County, Texas, appears to be controlled by vadose-water flow rate and kinetics of dissolution and precipitation of silicate minerals. Feldspar grains more commonly appear corroded by surface-reaction-controlled dissolution than argillized in situ. Kaolinite and smectite, which most likely precipitated from silica-rich vadose water, coat remaining framework grains. Where those grains are later dissolved, delicate clay molds remain. The relative abundances of feldspar and clay minerals are inversely related and vary with depth, reflecting the cumulative effect of feldspar weathering. Concentrations of dissolved and adsorbed cations generally are near massaction equilibrium. Recharge occurs from March to May (spring) and from October to November (autumn) when there is a net excess of water in the vadose zone. Dissolved ionic concentrations fluctuate seasonally with vadose-water residence time, suggesting that mass flux is close to mineral dissolution rate.

  6. Bluff and Bull in Education

    ERIC Educational Resources Information Center

    Sassoon, David

    2005-01-01

    Telling a lie, according to Harry G. Frankfurt, is different from engaging in bullshit because, while a lie is designed to insert a particular falsehood at a specific point in a set or system of beliefs in order to avoid the consequences of having that occupied by truth, bullshit neither misrepresents the state of affairs to which it refers nor…

  7. Ab initio studies of the formation of a Y1-xNi2 superstructure with ordered Y vacancies

    NASA Astrophysics Data System (ADS)

    Lindbaum, A.; Hafner, J.; Gratz, E.

    1999-02-01

    Ab initio total-energy calculations have been performed to study the structural stability of Y1-xNi2. In the literature (Villars P and Calvert L D 1985 Pearson's Handbook of Crystallographic Data for Intermetallic Phases (Materials Park, OH: American Society for Metals)) YNi2 is often considered to show the cubic Laves phase structure, but x-ray diffraction experiments of Latroche et al ( J. Less-Common Met. 161 L27) showed that YNi2 crystallizes in a superstructure of C15 with ordered Y vacancies with a stoichiometry of approximately Y0.95Ni2. The total-energy calculations for the superstructure and for the ideal C15 structure, as well as for the neighbouring phases in the Y-Ni phase diagram YNi and YNi3, confirm that the formation of the superstructure with Y vacancies is favoured against the formation of the pure C15 compound YNi2. The calculated relaxation of the atoms around the vacancies is also in good agreement with the experimental results (Latroche et al), demonstrating that the relaxation of strains in the Y sublattice is the driving mechanism for formation of vacancies. In addition, the electronic properties of the vacancy superstructure have been examined.

  8. Alteration, mass conservation, and magmatic compositions of lavas of the Columbia River flood basalt province: Insights from the Sentinel Bluffs Member, Grande Ronde Basalt

    NASA Astrophysics Data System (ADS)

    Sawlan, M. G.

    2013-12-01

    Understanding magmatic processes involved in flood basalt volcanism, and the ability to correlate flows within the voluminous, widespread lava fields requires accurate characterization of their magmatic geochemistry. Although evidence of alteration is widespread, modifications to lava chemistry by secondary processes are poorly understood. This results in uncertainty in the interpretation of geochemical analyses of Columbia River Basalt Group lava flows, particularly those of the Grande Ronde Basalt (GRB), in which chemical differences between the lavas are subtle. This problem is addressed here using major and trace element analyses (XRF) of samples of the Sentinel Bluffs Member (SB) of the GRB collected from multiple stratigraphic sections within the Columbia Plateau, Columbia River Gorge and Coast Ranges. Sixteen chemical groups, comprising 1-3 flows each, are recognized among multiple SB lava compositions. Flows assigned to three or four successive chemical groups are, in turn, assigned to more broadly defined chemical series based on shared characteristics such as immobile element ratios. Magmatic and alteration trends among SB compositions are clearly distinguished in Al-Ti variations. Magmatic trends are defined by inverse correlation of Al2O3 and TiO2. Alteration trends, extending from the magmatic array to higher abundances, are characterized by constant Al2O3/TiO2. Paired enrichments in Al and Ti, as well as other immobile elements, result from concentration in the residuum of altered rock that has lost mass due to soluble cation removal. Such enrichments are inversely proportional to mass loss. A mass conservation index (MCI), derived from Al-Ti systematics, quantifies mass retention and has multiple applications. MCI normalization eliminates residual concentration accompanying mass loss such that MCI-normalized immobile element abundances in altered rock agree with those in high-MCI rock. Compositions filtered to high-MCI values more closely reflect

  9. High-resolution, paired geochemical-paleomagnetic stratigraphy of the Sentinel Bluffs Member of the Grande Ronde Basalt, Columbia River Basalt Group

    NASA Astrophysics Data System (ADS)

    Sawlan, M. G.; Hagstrum, J. T.

    2012-12-01

    The Sentinel Bluffs Member (SB) of the Grande Ronde Basalt (GRB) is the youngest stratigraphic unit of the GRB, and is distinguished from other lava flows within the GRB's upper normal polarity magnetozone (N2) by its relatively high MgO content. We collected co-located samples in SB lava flows for major and trace element (XRF) geochemical and paleomagnetic analyses from 7 stratigraphic sections in the central and eastern Columbia River Gorge, on the southwestern Columbia Plateau, at Sentinel Gap on the western Plateau, and at Patrick Grade in the northern Blue Mountains of eastern WA. For the Sentinel Gap section we have adopted the paleomagnetic data from Coe et al. [1978, Rockwell Hanford report RHO-BWI-ST-2], except for our sampling of the Levering flow (not previously sampled) and resampling of their SB flow "H". Paleomagnetic directions for SB flows define 7 stratigraphically controlled groups (I-VII) varying primarily in inclination. Groups I, III, and V have moderate inclinations (means of 55°-57°), groups II and IV have steeper inclinations (67°-69°), and groups VI and VII have the steepest inclinations (72°-78°). SB lava flows exhibit relatively large chemical variations, spanning nearly 1 wt% MgO. Within this span, we recognize 11 discrete chemical groups (1-11, numbered in stratigraphic order) mainly on the basis of TiO2-MgO variations. Early SB eruptions include low- and high-Cr subgroups, and chemical groups 1 and 2 (paleomagnetic groups I-III) are subdivided on the basis of a ~2x difference in Cr abundances (e.g., 16-20 ppm Cr in groups 1a and 2a, 32-38 ppm Cr in groups 1b and 2b). Low-Cr flows are observed only in the lower parts of the SB stratigraphy. Three group 1 (I-II) lava flows that are the lowest SB flows in three sections have similar major element abundances, but differ from each other either in trace element abundances and/or paleomagnetic direction. We infer that the earliest SB flows have moderate inclinations (56°) and include

  10. Formation of lunar basin rings

    USGS Publications Warehouse

    Hodges, C.A.; Wilhelms, D.E.

    1978-01-01

    The origin of the multiple concentric rings that characterize lunar impact basins, and the probable depth and diameter of the transient crater have been widely debated. As an alternative to prevailing "megaterrace" hypotheses, we propose that the outer scarps or mountain rings that delineate the topographic rims of basins-the Cordilleran at Orientale, the Apennine at Imbrium, and the Altai at Nectaris-define the transient cavities, enlarged relatively little by slumping, and thus are analogous to the rim crests of craters like Copernicus; inner rings are uplifted rims of craters nested within the transient cavity. The magnitude of slumping that occurs on all scarps is insufficient to produce major inner rings from the outer. These conclusions are based largely on the observed gradational sequence in lunar central uplifts:. from simple peaks through somewhat annular clusters of peaks, peak and ring combinations and double ring basins, culminating in multiring structures that may also include peaks. In contrast, belts of slump terraces are not gradational with inner rings. Terrestrial analogs suggest two possible mechanisms for producing rings. In some cases, peaks may expand into rings as material is ejected from their cores, as apparently occurred at Gosses Bluff, Australia. A second process, differential excavation of lithologically diverse layers, has produced nested experimental craters and is, we suspect, instrumental in the formation of terrestrial ringed impact craters. Peak expansion could produce double-ring structures in homogeneous materials, but differential excavation is probably required to produce multiring and peak-in-ring configurations in large lunar impact structures. Our interpretation of the representative lunar multiring basin Orientale is consistent with formation of three rings in three layers detected seismically in part of the Moon-the Cordillera (basin-bounding) ring in the upper crust, the composite Montes Rook ring in the underlying