Sample records for calvert bluff formation

  1. Stratigraphy of the Calvert Bluff Formation of the Wilcox Group, Brazos County, Texas

    E-print Network

    May, Audrey Gail

    1994-01-01

    Wilcox Group sediments are classified into three main formations: a lower Hooper Formation, a middle Simsboro Formation, and an upper Calvert Bluff Formation. The Calvert Bluff and Simsboro formations have been interpreted as fluvial...

  2. Hydrogeology and groundwater modeling of a Calvert Bluff aquifer

    E-print Network

    Lawrence, James

    1989-01-01

    P? pluviat pluvial Det t ai c Deltaic Reklaw Carrizo sand Calvert Bluff ctay . . . . . gimsboro . . . . . . X 0 D Hooper; Q Major Lignite 4s Occurrences MIDWAY GROUP Figure 2. Stratigraphic section in the Eocene of East Texas (Kennedy, 1981). 10...

  3. 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 of the coal bed was very wet with minimal detrital input. Relatively high concentrations of crypto-humotelinite were found in samples from the top and base of the coal bed. The presence of abundant crypto-humotelinite in this part of the coal bed suggests the accumulation of wood-rich peat under conditions conducive to a high degree of tissue preservation in the peat mire. Although several of the trace elements (Be, Co, Ni, and Sb) exhibit enrichment in these samples, they are not necessarily chemically associated with humotelinite. We infer that these elements, with the exception of Be, are possibly associated with deposition of the roof and floor rock of the coal bed; however, further analytical work would be necessary to confirm this hypothesis. Beryllium may have an organic origin. ?? 1997 Elsevier Science B.V.

  4. 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.

  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. 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.

  7. Depositional environments and reservoir properties of the upper Queen Formation, Concho Bluff and Concho Bluff North fields, Midland basin, Texas

    SciTech Connect

    Mazzullo, J.; Newsom, D.; Harper, J.; McKone, C.; Price, B. (Texas A and M Univ., College Station (United States))

    1992-04-01

    The upper Queen Formation (Upper Permian) in Concho Bluff and Concho Bluff North fields (Crane, Upton, and Ector counties, Texas) consists of four thick (6-11 m) clastic members separated by evaporite members, and contains several major sandstone reservoirs. A study of cores and logs from the upper Queen was done to determine its depositional environments and the properties of its sandstone reservoirs. Four facies are present in the upper Queen. Facies 1 consists of planar- and wavy-laminated fine and very fine sandstones and silty sandstones deposited in fluvial sandflats and delta-plains. Facies 2 consists of wavy-laminated siltstones and haloturbated mudstones with anhydrite nodules deposited in subaqueous prodelta environments and subaerial saline mudflats. Facies 3 consists of well-sorted fine to very fine sandstones with horizontal and inclined planar laminae deposited in eolian sand sheets. Facies 4 consists of massive to laminated halite and anhydrite deposited in hypersaline playas. The vertical sequence of these facies indicates that the upper Queen was deposited during four cycles of fan-delta progradation into and retreat from coastal-plain playas during a sea level lowstand in the Midland basin. The sandstones of the fluvial sandflat and eolian sand-sheet facies constitute the reservoirs of the upper Queen in the fields. The average cumulative thickness of these facies is 8 m, and the fields average 16% porosity and 40-50 md of permeability. The remaining facies are all nonproductive with averagge porosities of less than 10% and average permeabilities of less than 1 md.

  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. Facies architecture of the upper Calvert Bluff Formation exposed in the highwall of Big Brown Mine, Fairfield, Texas

    E-print Network

    Sturdy, Michael Dale

    2006-10-30

    of Big Brown Mine, near Fairfield, Texas. Observed bedding and facies architecture are interpreted in terms of temporal changes, depositional environments and sequence stratigraphic setting. A three dimensional grid of 89 subsurface logs is correlated...

  10. Facies architecture of the upper Calvert Bluff Formation exposed in the highwall of Big Brown Mine, Fairfield, Texas 

    E-print Network

    Sturdy, Michael Dale

    2006-10-30

    this highwall exposure records more recent erosion, followed by development of modern soil horizons. The Big Brown Mine highwall exposes a relatively complete high-frequency Paleocene stratigraphic sequence developed in an area landward of the shoreline position...

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

    SciTech Connect

    Rovey, C.W. II (Southwest Missouri State Univ., Springfield, MO (United States))

    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.

  12. 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.

  13. 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.

  14. Ray Lemoine, Cedar Bluffs Public Schools, Cedar Bluffs, NE 2008 Geologic Time

    E-print Network

    Frank, Tracy D.

    Ray Lemoine, Cedar Bluffs Public Schools, Cedar Bluffs, NE © 2008 Geologic Time Materials: Geologic Time Scale Map of Nebraska Bedrock Geology Web access Background: This would make a great introductory lesson to Geologic Time. Students should understand rock formation and weathering. The primary

  15. Paleoecology of the Quarry 9 vertebrate assemblage from Como Bluff, Wyoming (Morrison Formation, Late Jurassic)

    Microsoft Academic Search

    Matthew T. Carrano; Jorge Velez-Juarbe

    2006-01-01

    Quarry 9 is among the richest microvertebrate localities in the Morrison Formation, having thus far produced the remains of dozens of Late Jurassic taxa. Because this lenticular claystone deposit records such a high diversity of contemporaneous species, it provides an exceptionally detailed view of their paleoecology and local paleoenvironment. In this study, we reexamined the entire Quarry 9 collection, totaling

  16. Calvert: an historical geography

    E-print Network

    McMillan, Frank N

    1984-01-01

    , Alabama, Georgia, and South Carolina. The plantation system, with its emphasis on a single crop for production and export, was the chief economic base of this world. The system was supported by slave labor and slave ownership was therefore...-Axtell-Tabor series in the northwest, and Patilo-Stedham series in the southeast. Soils at Calvert and in the surrounding uplands belong to the Lufkin-Axtell-Tabor series. These soils are characterized by loamy surface layers and mottled gray and red or yellow...

  17. Calvert Cliffs tiger beetle

    NSDL National Science Digital Library

    Johns Hopkins University. Center for Technology in Education (CTE)

    2004-01-01

    This video clip, viewable in Windows Media Player, introduces students to the rare puritan tiger beetles that live in Maryland's Calvert Cliffs. The two and a half-minute clip addresses the beetle's lifecycle, focusing on its dependence on the area's beachside cliffs. A discussion of the beetle's reproduction and feeding behaviors is accompanied by footage of adult beetles on the shore and of larvae tunneling holes into the cliffs. An entomologist lists the conservation actions that need to be taken to remove the beetle from the state list of endangered species. Copyright 2005 Eisenhower National Clearinghouse

  18. From Bluff to Backwater

    USGS Multimedia Gallery

    This is an aerial view of Pool 7 of the Mississippi River south of Trempealeau, WI. This photo highlights the different habitats for plants and wildlife from the bluffs that parallel the river to its quiet backwaters. Balanced with that is the fact that the Mississippi River is a commercial highway ...

  19. 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

  20. 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 the toes of slopes from wave action. Once shoreline retreat ends, sloughing of sediment from bluff faces gives way to longer-term landslide processes. The bluff top recedes until a stable 35-degree slope is attained. Thus, simple shoreline protection methods may not preserve property at the bluff edge.

  1. Instructions for submitting your application for the University Libraries Lance & Elena Calvert Undergraduate Research Award

    E-print Network

    Hemmers, Oliver

    Instructions for submitting your application for the University Libraries Lance & Elena Calvert abbreviations. c. When you click the Sign Up button you will be instructed that an email will be sent to you/project. Copy/paste if you like. Check formatting of characters 2. Authors: For group projects enter names

  2. Calvert Cliffs zooplankton entrainment study. Final report

    SciTech Connect

    Bradley, B.P.

    1980-01-01

    Entrainment studies to evaluate plant effects on zooplankton were conducted at the Calvert Cliffs Nuclear Plant. Specific effects tested were (a) the spatial and temporal variation of zooplankton density; (b) pump sampling efficiency; (c) delayed mortality; (d) vital staining as an indicator of mortality.

  3. 77 FR 70431 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-26

    ...Federal Energy Regulatory Commission [Docket No. PR13-10-000] 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...

  4. 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.

  5. 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.

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

    Microsoft Academic Search

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

    1991-01-01

    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

  7. Paleomagnetic and rock magnetic evidence for a secondary yet early magnetization in large sandstone pipes and host Late Middle Jurassic (Callovian) Summerville Formation and Bluff Sandstone near Mesita, west central New Mexico

    NASA Astrophysics Data System (ADS)

    Geissman, John W.; Harlan, Stephen S.

    2004-07-01

    Processes responsible for the acquisition of ancient yet secondary magnetizations are important facets of the geologic history of rocks and, when the age of such magnetizations can be estimated with confidence, provide useful information on the ancient geomagnetic field. In west central New Mexico near Mesita, on the Colorado Plateau, hematitic sandstone and siltstone beds of the Middle Jurassic (Callovian) Summerville Formation and overlying Bluff Sandstone are host to numerous large (up to 100 m2 in map area) pipe-like sandstone bodies. The pipes are as strongly cemented by hematite (colors range from 10R 6/6 to 10R 3/4) as the host strata; paleomagnetic data from them and their host strata are interpreted to indicate that these rocks have been remagnetized, probably in association with sandstone pipe formation. Reverse polarity magnetizations isolated in both alternating field and thermal demagnetization from pipes are well grouped and are similar to, and not statistically distinct from, those in adjacent host strata. The grand-mean direction for 16 sites (7 sites in sandstone pipes and 9 in host strata), corrected for slight (5°) west-northwest tilt of the strata, is D = 163.0°, I = -44.3° (?95 = 2.7°, k = 169). This direction yields a pole position of 72.8°N, 135.7°E (dp = 2.1°, dm = 3.4°). Assuming a modest (i.e., ˜5°) clockwise rotation of the Colorado Plateau, the pole lies at 68.7°N, 143.8°E. Median destructive fields for the remanence in pipes and host strata are typically 40-50 mT; over 90% of the remanence is "unblocked" or removed during changes in the magnetic mineralogy by temperatures of ˜400-450°C. Isothermal remanent magnetization (IRM) acquisition data, and thermal demagnetization of "saturation" IRM, however, demonstrate that the dominant magnetic phase is of high coercivity and relatively high (above 600°C) laboratory unblocking temperatures in both sandstone pipes and host strata, yet it does not appear to contribute significantly to the characteristic remanent magnetization. The similarity in demagnetization properties between pipes and adjacent host strata, the absence of a well-defined high unblocking temperature remanence that is more typical of hematite-cemented detrital strata, and the essentially uniform reverse polarity of the remanence are all interpreted to indicate that pipes and host strata contain secondary, yet early acquired magnetizations and that magnetization acquisition continued after pipe injection. We propose that acquisition of the secondary magnetization took place in the presence of alkaline, high pH brines formed by the dissolution of the underlying gypsum-dominated Lower Jurassic Todilto Formation strata and therefore the remanence is early in age. On the basis of a comparison with Summerville and Morrison (Middle and Late Jurassic) paleomagnetic poles from rocks on the Colorado Plateau, we interpret the secondary remanence in Summerville strata and sandstone pipes near Laguna to be latest Middle to Late Jurassic in age. If realistic, this interpretation further emphasizes the importance of fluid-rock interaction in the acquisition of secondary magnetizations.

  8. The Interaction Vortex Flow Around Two Bluff Cylinders

    NASA Astrophysics Data System (ADS)

    Yokoi, Y.; Hirao, K.

    2013-04-01

    In this study, the interaction vortex flow features around a pair of parallel arranged bluff cylinders were observed by visualizing water flow experiment at the range of the gap ratio G/d=0~3. It was obtained that the result of established wind tunnel test and the result of this water tank test agreed about the characteristics of vortex shedding when varying the distance of circular cylinder gap. The flow pattern and vortex shedding frequency of another type bluff cylinder (triangular and square cylinder) were also investigated. As a result of the experiment, it was shown that the flow pattern of wake flow was divided into three kinds (coupled vortex streets, biased gap flow and single vortex street) regardless of the cylinder section shape and cylinder size. Then, the region of the appearance of flow pattern was shown about each case. In the case where two each other independent vortex streets were formed, three typical flow patterns of vortex formation (in-phase coupled vortex streets, out-of-phase coupled vortex streets and complication coupled vortex streets) were observed. It was known that three configuration of vortex formation appear intermittently and alternatively.

  9. 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…

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ...Operation Regulation; Arkansas Waterway, Pine Bluff, AR AGENCY: Coast Guard, DHS...the Arkansas Waterway at Mile 67.4 at Pine Bluff, Arkansas. Vessel operators shall...Operation Regulation; Arkansas Waterway, Pine Bluff, AR in the Federal Register...

  12. Investigation on flame stability of bluff-body and slitted bluff-body burner in diesel fog combustion

    Microsoft Academic Search

    Tang Wenhua; Qian Renzhang

    2011-01-01

    In order to determine the bluff body and slitted bluff body flame stability and combustion performance, atmospheric low-speed experimental platform is used to carry out diesel fog combustion experiment for comparison of two types of bluff body, which are respectively streamlined V-form added straight channel and triangle V-form added straight channel. Results have shown that under the same condition, nonslit

  13. 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.

  14. 76 FR 10581 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-25

    ...DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR11-87-000] 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...

  15. 78 FR 21930 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ...DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR13-45-000] 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...

  16. 78 FR 41397 - Moss Bluff Hub, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ...Moss Bluff) filed a revised Statement of Operating Conditions (SOC) pursuant to sections 284.123 and 284.224 of the Commission's...CFR 284.123 and 284.224). Moss Bluff states the revised SOC reflects modifications to Section 22 (Electronic...

  17. 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

    ...Regulatory Commission [Docket No. ER11-2954-000] DTE Calvert City, LLC; Supplemental Notice that Initial Market- Based...supplemental notice in the above-referenced proceeding of DTE Calvert City, LLC's application for market-based rate...

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

    Microsoft Academic Search

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

    1991-01-01

    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

  19. GPU accelerated simulations of bluff body flows using vortex particle methods

    E-print Network

    Cottet, Georges-Henri

    GPU accelerated simulations of bluff body flows using vortex particle methods Diego Rossinelli in press as: D. Rossinelli et al., GPU accelerated simulations of bluff body flows using vortex particle Penalization Bluff body flows a b s t r a c t We present a GPU accelerated solver for simulations of bluff body

  20. 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.

  1. Scotts Bluff: Shared Heritage Travel Itinerary

    NSDL National Science Digital Library

    Located along the North Platte River Valley in Nebraska, the Scotts Bluff region is rich in history. The area was traversed by settlers on their way West throughout the 19th century, and it is the subject of this Shared Heritage Travel Itinerary created by the National Park Service. This Itinerary was produced in cooperation with the city of Scottsbluff, the city of Gering, the Nebraska State Historic Preservation Office, and the National Conference of State Historic Preservation Officers. As with the other itineraries in the series, this one includes a "List of Sites" (complete with information about their significance), maps, and thematic essays like "Trappers, Traders, and Travelers" and "Cultivation, Irrigation, and Urbanization". There are many highlights here, but visitors shouldn't miss the sections on the Morrill County Courthouse or the Marquis Opera House in Scottsbluff.

  2. 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

  3. 76 FR 53426 - Moss Bluff Hub, LLC; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ...ENERGY Federal Energy Regulatory Commission [Docket No. PR11-123-000] 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,...

  4. Ray Lemoine, Cedar Bluffs Public Schools, Cedar Bluffs, NE 2008 Understanding Geologic Formations

    E-print Network

    Frank, Tracy D.

    guage) Background: Students should know the rock cycle and the three main types of rocks; sedimentary Materials: Bedded rock samples (or pictures) Fossilized rock samples (or pictures) Pictures from Geology Field Course, or equivalent Rock I.D. flow charts Rock test kits (hardness test, acid test, grain size

  5. 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.

  6. 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.

  7. The lithology, environment of deposition, and reservoir evaluation of sandstones in the Upper Queen Formation (Guadalupian, Permian) at Concho Bluff North and Jennifer Fields, Upton and Ector Counties, Texas 

    E-print Network

    Harper, James Broox

    1990-01-01

    Committee) R. R. Berg (Member) Steve Poston (Member) John Sp g (Head of Department) May 1990 ABSTRACT The Lithology, Environment of Deposition, and Reservoir Evaluation of Sandstones in the Upper Queen Formation (Guadalupian, Permain) at North.... Finally, I would like to thank my parents for their boundless love and support throughout my pursuits. vz TABLE OF CONTENTS ABSTRACT. ACKNOWLEDGEMENTS. TABLE OF CONTENTS LIST OF FIGURES. Page vi ~ ~ ~ V11i INTRODUCTION. GEOLOGIC HISTORY...

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

    Microsoft Academic Search

    R. O. VanAtta; K. B. Kelty

    1985-01-01

    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

  9. Research on flow around bluff bodies, flow induced vibrations

    Microsoft Academic Search

    Tianfeng Sun; Erjie Cui

    1987-01-01

    The flow around bluff bodies and the related flow induced vibrations are reviewed. The emphasis is placed on investigations of the flow around a circular cylinder and rectangular prism, and the interference between the two cylinders in various arrangements. The effects of body oscillation, incident shear and flow turbulence are discussed in detail. Some specific problems remaining to be solved

  10. Gosses bluff — diapir, crypto?volcanic structure or astrobleme?

    Microsoft Academic Search

    K. A. W. Crook; P. J. Cook

    1966-01-01

    Gosses Bluff, west of Alice Springs, Northern Territory, comprises a roughly circular rim of steeply dipping sandstone, locally overturned with downward facing folds, surrounding a topographically lower core of steeply dipping faulted sandstone, shale, and limestone. Abundant shattercones occur both in outcrop and to depths of 1,000 m. The structure lies on an’ anticlinal trend?Structural, gravity, seismic and drill hole

  11. 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

  12. 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

  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. 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

  15. 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

  16. 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

  17. 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

    ...52-016; NRC-2008-0250] UniStar Nuclear Energy, Combined License Application for Calvert...3, Exemption 1.0 Background UniStar Nuclear Energy (UNE), on behalf of Calvert Cliffs Nuclear Project, LLC and UniStar Nuclear...

  18. Trace fossils from the Rock Bluff Limestone (Pennsylvanian, Kansas)

    E-print Network

    Maerz, R. H., Jr.; Kaesler, R. L.; Hakes, W. G.

    1976-01-15

    of bottom sediments. Brachi- opod-pelecypod and upper crystalline microfacies occupied the upper part, with deposition judged to have been in "rather shallow water." At the locality studied, the lower one-third of the unit consists of a fusulinid... Limestone could be preserved. Un- fortunately, no ophiuroid remains have yet been found in either the Oskaloosa Shale or the Rock Bluff Limestone. The burrows were found to contain a variety of biotic constituents, including fusulinids, brachi- opod...

  19. Modelling of turbulent diffusion flames stabilized on a bluff body

    Microsoft Academic Search

    Chang E. Lee; Ok Y. Yang; Yoshiaki Onuma

    1992-01-01

    The present authors previously proposed a modification of the k-epsilon turbulence model in the modeling of jet diffusion flames to represent the so-called laminarization phenomenon, caused by combustion in the low-turbulence region, and recently found, in experiments on diffusion flames stabilized on a bluff body, that this phenomenon also exerts an important influence on the structure of these flames with

  20. UNLV University Libraries Lance & Elena Calvert Undergraduate Research Award Scoring Rubric Essay (20 pts)

    E-print Network

    Hemmers, Oliver

    in the research process, even if it challenges student's value system or counters their thesis argumentUNLV University Libraries Lance & Elena Calvert Undergraduate Research Award Scoring Rubric 1 Search strategies omitted or very general, for example: Does not describe transferable or reproducible

  1. Comparing classes of finite structures W. Calvert, D. Cummins, J. F. Knight, and S. Miller

    E-print Network

    Calvert, Wesley

    Comparing classes of finite structures W. Calvert, D. Cummins, J. F. Knight, and S. Miller February], [14]. In this work, each class consists of structures with the same countable universe, say #, and with the same language, usually finite. For a given finite language L, the class of all L

  2. Comparing classes of finite structures W. Calvert, D. Cummins, J. F. Knight, and S. Miller

    E-print Network

    Calvert, Wesley

    language, usually finite. For a given finite language L, the class of all L-structures with universe hasComparing classes of finite structures W. Calvert, D. Cummins, J. F. Knight, and S. Miller February]. In this work, each class consists of structures with the same countable universe, say , and with the same

  3. Comparing classes of finite structures W. Calvert, D. Cummins, J. F. Knight, and S. Miller

    E-print Network

    Calvert, Wesley

    with the same countable universe, say !, and with the same language, usually finite. For a given finite language Comparing classes of finite structures W. Calvert, D. Cummins, J. F. Knight L, the class of * *all L-structures with universe ! has a natural topological structure

  4. Indicator tests for the creep of rock salt from borehole Moss Bluff 2, Moss Bluff Dome, Texas

    SciTech Connect

    Wawersik, W.R.

    1992-11-01

    Creep tests were performed on a representative sample of rock salt from borehole Moss Bluff 2 (MB2), Moss Bluff dome near Houston, Texas. Moss Bluff 2 is located at the site of a compressed gas storage cavern of Tejas Power Corporation. Four triaxial experiments were conducted at two values of principal stress difference and two representative temperatures. The minimum observed creep rates at the end of each test varied between 5.2[times]10[sup [minus]9] 1/s and 2.14[times]10[sup [minus]8] 1/s. Comparisons of the present results with existing data for rock salt from other locations suggest that the steadystate creep characteristics of MB2 salt, depth 3349 ft (1098.8 m), are intermediate to those measured for the US Strategic Petroleum Reserve at West Hackberry and Bryan Hound, which included the most creep resistant rock salt ever tested at Sandia National Laboratories. Creep parameters are suggested for first-order sensitivity calculations.

  5. Indicator tests for the creep of rock salt from borehole Moss Bluff 2, Moss Bluff Dome, Texas

    SciTech Connect

    Wawersik, W.R.

    1992-11-01

    Creep tests were performed on a representative sample of rock salt from borehole Moss Bluff 2 (MB2), Moss Bluff dome near Houston, Texas. Moss Bluff 2 is located at the site of a compressed gas storage cavern of Tejas Power Corporation. Four triaxial experiments were conducted at two values of principal stress difference and two representative temperatures. The minimum observed creep rates at the end of each test varied between 5.2{times}10{sup {minus}9} 1/s and 2.14{times}10{sup {minus}8} 1/s. Comparisons of the present results with existing data for rock salt from other locations suggest that the steadystate creep characteristics of MB2 salt, depth 3349 ft (1098.8 m), are intermediate to those measured for the US Strategic Petroleum Reserve at West Hackberry and Bryan Hound, which included the most creep resistant rock salt ever tested at Sandia National Laboratories. Creep parameters are suggested for first-order sensitivity calculations.

  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

    ...2013-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation...REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

  7. 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

    ...2011-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation...REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

  8. 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

    ...2010-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation...REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

  9. 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

    ...2012-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation...REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

  10. 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

    ...2014-07-01 false Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and navigation...REGULATIONS § 207.169 Oklawaha River, navigation lock and dam at Moss Bluff, Fla.; use, administration, and...

  11. Numerical and physical modeling of bluff body flow and dispersion in urban street canyons

    Microsoft Academic Search

    Cheng-Hsin Chang; Robert N. Meroney

    2001-01-01

    To develop reliable computer models for the bluff body flow and transport of pollutants or chemical and biological (CB) agents in urban environments requires accurate measurements of the basic flow fields for carefully controlled, well-known conditions. Fluid modeling in an industrial wind tunnel provides an opportunity to produce accurate simulations of the bluff body flow and transport of urban pollution

  12. 75 FR 33799 - Moss Bluff Hub, LLC; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ...ENERGY Federal Energy Regulatory Commission [Docket No. PR10-28-000] 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...

  13. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla...NAVIGATION REGULATIONS § 207.170 Federal Dam, Oklawaha River, Moss Bluff, Fla...times of high water, the discharge past the dam shall be regulated in such manner as...

  14. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla...NAVIGATION REGULATIONS § 207.170 Federal Dam, Oklawaha River, Moss Bluff, Fla...times of high water, the discharge past the dam shall be regulated in such manner as...

  15. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla...NAVIGATION REGULATIONS § 207.170 Federal Dam, Oklawaha River, Moss Bluff, Fla...times of high water, the discharge past the dam shall be regulated in such manner as...

  16. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla...NAVIGATION REGULATIONS § 207.170 Federal Dam, Oklawaha River, Moss Bluff, Fla...times of high water, the discharge past the dam shall be regulated in such manner as...

  17. 33 CFR 207.170 - Federal Dam, Oklawaha River, Moss Bluff, Fla.; pool level.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Federal Dam, Oklawaha River, Moss Bluff, Fla...NAVIGATION REGULATIONS § 207.170 Federal Dam, Oklawaha River, Moss Bluff, Fla...times of high water, the discharge past the dam shall be regulated in such manner as...

  18. An immersed boundary finite difference method for LES of flow around bluff shapes

    Microsoft Academic Search

    C. W. Li; L. L. Wang

    2004-01-01

    A three-dimensional numerical model using large eddy simulation (LES) technique and incorporating the immersed boundary (IMB) concept has been developed to compute flow around bluff shapes. A fractional step finite differences method with rectilinear non-uniform collocated grid is employed to solve the governing equations. Bluff shapes are treated in the IMB method by introducing artificial force terms into the momentum

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

    Microsoft Academic Search

    Brian D. Collins; Nicholas Sitar

    2008-01-01

    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

  20. 80 FR 21269 - UniStar Nuclear Energy; Combined License Application for Calvert Cliffs Nuclear Power Plant, Unit 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2015-04-17

    The U.S. Nuclear Regulatory Commission (NRC) is issuing an exemption in response to a December 31, 2014, letter from UniStar Nuclear Energy (UNE), on behalf of Calvert Cliffs Nuclear Project, LLC, and UniStar Operating Services, LLC, co-applicants for the combined license (COL) application for the Calvert Cliffs Nuclear Power Plant Unit 3 (CCNPP3), which requested an exemption to delay the......

  1. Carbonate turbidites in volcaniclastic metasedimentary rocks of the Mineral Bluff, Fm, Murphy, NC

    SciTech Connect

    Fritz, W.J.; La Tour, T.E.; Stakes, D.S.

    1985-01-01

    Outcrops of the metasedimentary Mineral Bluff Fm near Murphy, North Carolina contain thin lenses to discontinuous layers of calc-silicate in volcaniclastic mudstone. Despite the metamorphism, sedimentary structures preserved in the mudstones include: ripple cross laminations, scour surfaces, crossbedding and graded beds. The calc-silicate layers vary from 2-25cm thick and are zoned from carbonate-rich center to silicate-rich margins. May layers have no carbonate center preserved. Major calc-silicate minerals are carbonate, plagioclase, hornblende, Ca-garnet, and quartz; accessory minerals are clinozoisite, apatite, Fe-Ti oxides, and pyrite. Siltstone immediately adjacent to calc-silicate layers contains much biotite whose abundance decreases away from the calc-silicate layers. Greater original carbonate in siltstone nearest carbonate layers would have facilitated biotite growth. Within calc-silicate layers, hornblende is concentrated near both margins, but in greater concentration near stratigraphic tops. The authors also interpret this as grading within original muddy carbonate turbidites. The calc-silicate turbidite layers may have been derived from the nearby Murphy Marble, a large time-equivalent late Proterozoic or early Paleozoic carbonate unit. The Murphy Marble was a large shallow water carbonate reef associated with an island arc. Other time-equivalent, nearshore rock units in the area are the beach sandstone of the Nottely Quartzite and the locally carbonate-rich volcaniclastic Brasstown Formation. The authors envisage the depositional environment for the Mineral Bluff Fm as a deep basin, distal from the island arc, that received fine-grained volcaniclastic debris from the arc, episodically interrupted by a carbonate turbidity flow.

  2. 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.

  3. 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. [Univ. of Chicago, IL (United States). Dept. of Geophysical Sciences

    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.

  4. 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.

  5. 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.

  6. The Role of Bluff-Body Roughness Elements on Turbulent Evaporative Fluxes from Porous Surfaces: Momentum and Energy Partitioning

    NASA Astrophysics Data System (ADS)

    Or, D.; Haghighi, E.; Lagüela, S.; Aminzadeh, M.

    2014-12-01

    Bluff body obstacles in turbulent flows are common in many natural and engineering applications (from desert pavement and boulders to shrubs). The deceivingly simple geometry of a surface-mounted obstacle in a boundary layer induces a complex and unsteady flow field that affect the surface drag partitioning and transport of scalars form surrounding evaporating surfaces. The readily observable spatio-temporal distribution of localized evaporation rates from infrared measured thermal signatures provide the impetus for a simple zonation scheme that enables estimates of evaporative fluxes around an obstacle. Results from evaporation experiments from sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. The results show consistent enhancement of evaporating fluxes relative to a smooth surface to formation of vortices that induce thinner boundary layers. We also considered effects of obstacles on (solar) short wave radiation and energy partitioning over surfaces and successfully represented zonation of surface exchange due to momentum (drag partitioning) and variable surface energy balance on localized evaporation. A scheme for upscaling the results to evaporation from surfaces with multiple obstacles will be presented.

  7. 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 the wedge ice was exposed. This block-fall affected the area of approximately 800 m2, and the volume of frozen soil and ice involved in the block-fall was about 15,000 m3. The riverbank retreat due to thermal erosion and/or thermal denudation, measured from August 2007 to August 2011, varied from less than 10 to almost 100 m. An estimated retreat rate average for the whole 680 m long bluff was 11.4 m/year, but for the most actively eroded central part of the bluff (150 m long) it was 20.3 m/year, ranging from 16 to 24 m/year. During these 4 years, about 650,000 m3 of ice and organic-rich frozen soil were transported to the river from the retreating bank (more than 160,000 m3/year). Analysis of aerial photographs (1948-1979) and satellite images (1974-2013) showed that the riverbank was relatively stable till July 1995, when the Itkillik River changed its course and triggered extremely active thermal erosion. The total retreat of the riverbank in 1995-2010 varied from 180 to 280 m, which means that the average retreat rate for the most actively eroded part of the riverbank reached almost 19 m/year. Such a high rate of riverbank erosion over a long time period has not been reported before for any permafrost regions of Eurasia and North America.

  8. 40 CFR 81.50 - Metropolitan Omaha-Council Bluffs Interstate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Omaha-Council Bluffs Interstate Air Quality Control Region (Nebraska-Iowa) consists of the territorial area encompassed by the boundaries...Nebraska: Douglas County, Sarpy County. In the State of Iowa: Pottawattamie...

  9. 78 FR 20942 - Niobrara Confluence and Ponca Bluffs Conservation Areas, NE and SD; Draft Environmental Impact...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-08

    ...the Great Plains to the Eastern deciduous forest. It drains one-sixth of the...also experience scenic bluffs, forests, grasslands, and traditional...natural floodplain and upland forest communities, pastureland,...

  10. Energy Engineering Analysis Program. Lighting survey of selected buildings, Pine Bluff Arsenal, Pine Bluff, Arkansas. Executive summary. Final report

    SciTech Connect

    NONE

    1995-06-01

    The Energy Engineering Analysis Program (EEAP), Lighting Survey of Selected Buildings at Pine Bluff, Arsenal, was authorized by the U.S. Army, Little Rock District, Corps of Engineers, under Contract Number DACAO1-94-D-0038. Delivery Order Number 0001, dated 29 September 1994. The objectives of this Delivery Order (D.O.) are as follows: (A) Perform a site survey of 45 buildings selected by Arsenal personnel. The purpose of the site survey is to gather sufficient data to permit evaluation of possible Energy Conservation Opportunities (ECOs). (B) Evaluate possible and new ECOs. (C) Combine ECOs into recommended projects. (D) Prepare a comprehensive report to document the work performed, the results and the recommendations. The final report is to contain funds programming documentation.

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

    USGS Publications Warehouse

    Collins, B.D.; Sitar, N.

    2008-01-01

    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.

  12. Bluff evolution and long-term recession rates, southwestern Lake Michigan

    NASA Astrophysics Data System (ADS)

    Rovey, C. W.; Borucki, M. K.

    1994-06-01

    Where eroding cohesive sediments are present, Lake Michigan bluffs range up to 40 m in height, exposing multiple glacial stratigraphic units. Following 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 produce progressively higher bluffs and expose successively older units at the toe and beneath the lake. This process was 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 four offshore seismic and bottom-sampling profiles. It was picked as an inflection point in the lake bed, occurring offshore of dipping reflectors intersecting the lake bottom. The calculated average recession rate over a 2500-year duration of the modern stage is 1.5 m/yr in contrast to average rates of approximately 0.6 m/yr measured over the last century. Thus rates decrease through time as the terrace widens and wave energy is dampened. By correlating bluff height to recession distance, a third rate of approximately 2.7 m/yr for the first 940 years of recession is calculated from relict Nipissing bluffs. The three rates define a steeply decaying exponential curve in early stages of bluff retreat, flattening into a nearly linear function after 1000 years.

  13. 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.

  14. Experimental study on the interactions for bluff-body and swirl in stabilized flame process

    NASA Astrophysics Data System (ADS)

    Ge, Bing; Zang, Shu-Sheng

    2012-02-01

    This paper focuses on investigating the interaction effects for swirl and bluff-body in stabilized flame process. Particle image velocimetry was used to measure velocity fields in three burners. First, the comparison of flames in bluff-body stabilized burners with and without swirl is presented. The results of the experiments present the variations of bluff-body stabilized flame when swirl is added into burner: the maximum reverse flow velocity and the maximum mean average radial velocity decrease; the maximum radial root-mean squared fluctuating (rms) velocity increases; the values of the axial velocity peak on the side of nozzle axis are lower, and the distance between the peak and centerline is bigger; the location of the maximum radial rms velocity moves to the outlet of annular air-flow from central recirculation zone (CRZ). Then, the comparison of flames in swirl burners with and without bluff-body is provided. The results of the experiments show the changes of swirling flame when bluff-body is added into swirl burner: the air vortex in the CRZ moves to the burner; the peak values of axial mean and rms velocity decrease; the distance between centerline and the mean axial and rms velocity peak increase; the peak of mean radial velocity decreases, and the peak of rms raidial velocity increase. The data from this experiment can also be established as benchmarks for the development and validation of combustion numerical simulations.

  15. Alteration of volcaniclastic deposits at Minna Bluff: Geochemical insights on mineralizing environment and climate during the Late Miocene in Antarctica

    NASA Astrophysics Data System (ADS)

    Antibus, Joanne V.; Panter, Kurt S.; Wilch, Thomas I.; Dunbar, Nelia; McIntosh, William; Tripati, Aradhna; Bindeman, Ilya; Blusztajn, Jerzy

    2014-08-01

    minerals in volcaniclastic deposits at Minna Bluff, a 45 km long peninsula in the Ross Sea, are used to infer processes of alteration and environmental conditions in the Late Miocene. Glassy volcaniclastic deposits are altered and contain phillipsite and chabazite, low to high-Mg carbonates, chalcedony, and clay. The ?18O of carbonates and chalcedony is variable, ranging from -0.50 to 21.53‰ and 0.68 to 10.37‰, respectively, and ?D for chalcedony is light (-187.8 to -220.6‰), corresponding to Antarctic meteoric water. A mean carbonate 87Sr/86Sr ratio of 0.70327 ± 0.0009 (1?, n = 12) is comparable to lava and suggests freshwater, as opposed to seawater, caused the alteration. Minerals were precipitated at elevated temperatures (91 and 104°C) based on quartz-calcite equilibrium, carbonate 13C-18C thermometry (?47 derived temperature = 5° to 43°C) and stability of zeolites in geothermal systems (>10 to ˜100°C). The alteration was a result of isolated, ephemeral events involving the exchange between heated meteoric water and glass during or soon after the formation of each deposit. Near-surface evaporative distillation can explain 18O-enriched compositions for some Mg-rich carbonates and chalcedony. The ?18Owater calculated for carbonates (-15.8 to -22.9‰) reveals a broad change, becoming heavier between ˜12 and ˜7 Ma, consistent with a warming climate. These findings are independently corroborated by the interpretation of Late Miocene sedimentary sequences recovered from nearby sediment cores. However, in contrast to a cold-based thermal regime proposed for ice flow at core sites, wet-based conditions prevailed at Minna Bluff; a likely consequence of high heat flow associated with an active magma system.

  16. 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.

  17. 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.

  18. Brackish water in unsaturated confining beds at a Texas lignite mine

    Microsoft Academic Search

    2009-01-01

    Deposits of low permeability are hydrologic barriers between reclaimed land and juxtaposed aquifers and should limit the impact of mining on ground-water quality. Claystone and mudstone in argillaceous facies of the Calvert Bluff Formation (lower Eocene, Wilcox Group) function as confining beds in the East Texas Basin. In the subsurface and at the outcrop, water in argillaceous deposits is brackish

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

    SciTech Connect

    Abbott, L [ed.

    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.

  20. Return to Coalsack Bluff and the Permian Triassic boundary in Antarctica

    Microsoft Academic Search

    Gregory J. Retallack; Tara Greaver; A. Hope Jahren

    2007-01-01

    Coalsack Bluff was the first discovery site in Antarctica for the latest Permian to earliest Triassic reptile Lystrosaurus. This together with discovery of Permian Glossopteris leaves during the heroic age of Antarctic exploration, indicated not only that Antarctica was part of Gondwanaland, but also that Antarctic rocks recorded faunas from the greatest of all mass extinctions at the Permian Triassic

  1. Monitoring of Coastal Bluffs Using 3-D Laser Scanning and Conventional Mapping

    Microsoft Academic Search

    B. D. Collins; N. Sitar

    2002-01-01

    The coastal bluffs located south of San Francisco, California attract continuous attention due to the size and nature of their episodic failures both from large winter storms and from seismic shaking. Observations made by numerous researchers coupled with recent failures have led to a renewed interest in establishing proper set-back distances for future construction. However, data describing the size, volume,

  2. Experimental investigation of the aerodynamic noise radiated by a three-dimensional bluff body

    E-print Network

    Paris-Sud XI, Université de

    Experimental investigation of the aerodynamic noise radiated by a three-dimensional bluff body J.fischer@univ-poitiers.fr Proceedings of the Acoustics 2012 Nantes Conference 23-27 April 2012, Nantes, France 2335 #12;Aerodynamic. The present work is an experimental study of the aerodynamic noise radiated by a three-dimensional simplified

  3. Blowoff behavior of bluff body stabilized flames in vitiated and partially premixed flows

    Microsoft Academic Search

    Steven G. Tuttle

    2010-01-01

    Turbulent flame holding and blowoff characteristics of bluff body stabilized flames were measured in an enclosed rectangular duct with a triangular flame holder in vitiated, premixed and unvitiated, asymmetrically stratified flows. Blowoff stability margins were characterized, with chemiluminescence measurements performed by high-speed imaging to capture flame dynamics during blow off. As the equivalence ratio was decreased, local extinction along the

  4. Water Balance, Salt Loading, and Salinity Control Options of Red Bluff Reservoir, Texas 

    E-print Network

    Miyamoto, S.; Yuan, Fasong; Anand, Shilpa

    2007-01-01

    Red Bluff is the main reservoir of the Pecos River in Texas, and its maximum storage capacity adjusted to sediment accumulation is estimated at 357 million m3 (289,600 acre-ft.). Aside from the shortage of water entering ...

  5. 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

  6. Research on the flow around the bluff bodies and flow induced vibrations

    Microsoft Academic Search

    Tianfeng Sun; Erjie Cui

    1987-01-01

    The flow around bluff bodies and the related flow-induced vibrations are reviewed. The emphasis is placed on investigations of the flow around circular cylinders and rectangular prisms and the interference between two cylinders in various arrangements. The effects of body oscillation, incident shear, and flow turbulence are discussed in detail. Some specific problems which remain to be solved are also

  7. Estimation of bluff body transient aerodynamics using an oscillating model rig

    Microsoft Academic Search

    S. Mansor; M. A. Passmore

    2008-01-01

    A method for the estimation of transient aerodynamic derivatives from dynamic wind tunnel tests using time response data is presented in this paper. For the purposes of the study, the aerodynamic derivatives are considered to act as a stiffness and damping to the model motion. The experimental set-up consists of a simple bluff body (Davis model) constrained to oscillate with

  8. 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.

  9. Modelling finite-rate chemistry effects in nonpremixed turbulent combustion: Test on the bluff-body stabilized flame

    Microsoft Academic Search

    M. Gonzalez; R. Elamraoui; M. Obounou

    1997-01-01

    The validity of the turbulent combustion M.I.L. model has been investigated in the case of an unconfined bluff-body burner. This model allows for a distribution of turbulent timescales and makes use of a chemical delay time library; it is specially directed toward nonpremixed combustion with finite-rate chemistry effects. Because of the extreme complexity of the bluff-body flow, the study focuses

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

    DOEpatents

    Ortega, Jason M. (Pacifica, CA); Salari, Kambiz (Livermore, CA)

    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.

  11. A quasi-steady 3 degree-of-freedom model for the determination of the onset of bluff body galloping instability

    Microsoft Academic Search

    H. Gjelstrup; C. T. Georgakis

    2011-01-01

    In this paper, a quasi-steady three degree-of-freedom (3-dof) flow-induced galloping instability model for bluff-bodies is proposed. The proposed model can be applied generally for the prediction of onset of galloping instability due to negative aerodynamic damping of any prismatic compact bluff body in a fluidic medium. The three degrees of freedom refer to the bluff body's two orthogonal displacements perpendicular

  12. 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. It demonstrates that for low aspect ratio 3D bluff-bodies, like road vehicles, the flow control strategy is much different from the one used on airfoils: an early separation of the boundary layer can lead to a significant drag reduction if the circulation of the trailing vortices is reduced.

  13. Energy Engineering Analysis Program. Lighting survey of selected buildings, Pine Bluff Arsenal, Pine Bluff, Arkansas. Volume I, narrative report. Final report

    SciTech Connect

    NONE

    1995-06-01

    The Energy Engineering Analysis Program (EEAP), Lighting Survey of Selected Buildings at Pine Bluff, Arsenal, was authorized by the U.S. Army, Little Rock District, Corps of Engineers, under Contract Number DACAOl-94-D-0038. Delivery Order Number 0001, dated 29 September 1994. Objectives The objectives of this Delivery Order (D.O.), as shown in the Detailed Scope of Work (Appendix A, Volume II) are as follows: (A) Perform a site survey of 45 buildings selected by Arsenal personnel. The purpose of the site survey is to gather sufficient data to permit evaluation of possible Energy Conservation Opportunities (ECOs). (B) Evaluate possible and new ECOs. (C) Combine ECOs into recommended projects. (D) Prepare a comprehensive report to document the work performed, the results and the recommendations. The final report is to contain funds programming documentation.

  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. 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

  16. Hydrology and water quality of the Eocene Wilcox Group: significance for lignite development in East Texas

    Microsoft Academic Search

    C. D. Henry; J. M. Basciano; T. W. Duex

    1980-01-01

    Lignite development will place major demands on ground-water supplies. The Simsboro Formation and the Calvert Bluff Formation (a major lignite-bearing unit) of the Wilcox Group between the Colorado and Trinity Rivers constituted a test case to evaluate the availability and quality of ground water. Aquifer geometry (sand) was determined by comparing environmental geologic maps with subsurface sand-percent and net-sand maps

  17. 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)

  18. The composition and diagenesis of the Upper Queen Formation (Guadalupian, Permian) at Concho Bluff North and Concho Bluff Queen Fields, Upton and Crane Counties, Texas 

    E-print Network

    McKone, Charles Joseph

    1991-01-01

    ) potassium feldspar overgrowths, and (4) pore-filling anhydrite, dolomite, and halite cements during an early diagenetic phase. Subsequent dissolution of the anhydrite, dolomite, and halite by acidic pore-waters created high porosities (mean=15/o...-matrix and silt content of these sandflat deposits. In contrast, the finer grain size and higher clay-matrix and silt content prevented similar dissolution of cements within the mudflat facies, which have significantly lower porosities (mean&10/o...

  19. An experimental investigation of interference effects for high blockage bluff bodies in a slotted-wall wind tunnel test section

    Microsoft Academic Search

    C. A. Broughton; W. J. Rainbird; R. K. Kind

    1995-01-01

    This paper reports on an experimental investigation of interference effects when large area and large volume bluff bodies are tested in wind tunnels having longitudinally slotted testsection sidewalls and ceiling and a solid groundplane. Open area ratios of 30% and 45% were utilized. Three body shapes were tested at zero yaw and pitch angle: flat plates normal to the flow,

  20. Time-resolved blowoff transition measurements for two-dimensional bluff body-stabilized flames in vitiated flow

    Microsoft Academic Search

    Steven G. Tuttle; Swetaprovo Chaudhuri; Stanislav Kostka; Kristin M. Kopp-Vaughan; Trevor R. Jensen; Baki M. Cetegen; Michael W. Renfro

    Flame holding and blowoff characteristics of bluff-body stabilized, turbulent flames were measured in an enclosed rectangular duct with a triangular flame holder in vitiated, premixed flows. Blowoff stability margins were characterized with chemiluminescence measurements performed by high-speed imaging to capture flame dynamics during the approach to flame blow off. As the equivalence ratio was decreased, local extinctions along the flames

  1. Wind Sheltering of a Lake by a Tree Canopy or Bluff Topography Corey D. Markfort1,2

    E-print Network

    Porté-Agel, Fernando

    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

  2. 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

  3. Alteration and geochemical zoning in Bodie Bluff, Bodie mining district, eastern California

    USGS Publications Warehouse

    Herrera, P.A.; Closs, L.G.; Silberman, M.L.

    1993-01-01

    Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 million ounces of silver from the Bodie mining district, eastern California. The veins cut dacitic lava flows, pyroclastic rocks and intrusions. Sinter boulders occur in a graben structure at the top of Bodie Bluff and fragments of sinter and mineralized quartz veins occur in hydrothermal breccias nearby. Explosive venting evidently was part of the evolution of the ore-forming geothermal systems which, at one time, must had reached the paleosurface. Previous reconnaissance studies at Bodie Bluff suggested that the geometry of alteration mineral assemblages and distribution of some of the major and trace elements throughout the system correspond to those predicted by models of hot-spring, volcanic rock hosted precious metal deposits (Silberman, 1982; Silberman and Berger, 1985). The current study was undertaken to evaluate these sugestions further. About 500 samples of quartz veins and altered rocks, including sinter, collected over a vertical extent of 200 meters within Bodie Bluff were petrographically examined and chemically analyzed for trace elements by emission spectrographic and atomic absorption methods. Sixty-five samples were analyzed for major elements by X-ray fluorescence methods. The results of these analyses showed that, in general, alteration mineral assemblage and vertical geochemical zoning patterns follow those predicted for hot-spring deposits, but that geochemical zoning patterns for sinter and quartz veins (siliceous deposits), and altered wall rocks are not always similar. The predicted depth-concentration patterns for some elements, notably Au, Ag, Hg, and Tl in quartz veins, and Hg, As and Ag in wall rocks were not as expected, or were perturbed by the main ore producing zone. For both quartz veins and altered wall rocks, the main ore zone had elevated metal contents. Increased concentration of many of these elements could indicate proximity to this zone. However, irregularities in the distribution of some key elements, such as Au and Ag, relative to the predictive models suggest that a larger suite of elements be considered for exploration for ore zones within the district. ?? 1993.

  4. Drag reduction of a 3D bluff body using coherent streamwise streaks

    NASA Astrophysics Data System (ADS)

    Pujals, G.; Depardon, S.; Cossu, C.

    2010-11-01

    Separation on the rear-end of an Ahmed body is suppressed by means of large-scale coherent streaks forced on the roof of the model. These streaks originate from an array of suitably shaped cylindrical roughness elements and are amplified by the mean shear through the lift-up effect. Interacting with the mean velocity field at leading order, they induce a strong controlled spanwise modulation. The resulting streaky base flow is observed to sustain the adverse pressure gradient since PIV measurements as well as static wall pressure distributions show that the re-circulation bubble completely vanishes. These modifications of the topology of the flow are associated with a substantial drag reduction, which can be of about 10% when the roughness array is optimally placed on the roof of the bluff body.

  5. 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.

  6. Experimental investigation of galloping piezoelectric energy harvesters with square bluff bodies

    NASA Astrophysics Data System (ADS)

    Ewere, Felix; Wang, Gang; Cain, Brian

    2014-10-01

    In this paper, both a baseline galloping piezoelectric energy harvester (GPEH) with a square bluff body and an improved GPEH with an impact bump stop are tested in a wind tunnel in order to determine the system damping, electrical response and limit cycle oscillation (LCO) amplitude. In the baseline GPEH, harvested voltage, LCO amplitude and damping ratio vary with wind velocity and electrical load. They all increase with increasing wind velocity under the same electrical load. Under each wind velocity, the damping ratio increases from the short circuit load, reaches a peak value at the electrical load resulting in a maximum voltage, and reduces the value at the open circuit load. The LCO amplitude shows the opposite trend compared to the damping case. It decreases as the electrical resistance load increases and reaches the minimum value when the damping ratio is highest. A resistance load of 100 k? yields a maximum peak power output. The impact stop is introduced to reduce bending stresses and improve the fatigue life of the baseline GPEH. The performance of the improved GPEH depends on the stop design parameters such as gap size, stop location and contact area. Comprehensive tests were conducted to investigate the effect of each parameter on the performance of the improved GPEH and an optimal bump stop configuration was determined. Compared to the expected proportional reduction in both electrical and structural responses, a maximum 70% reduction in LCO amplitude and only a maximum 20% reduction in harvested voltage are achieved in our optimal improved GPEH. The time variable and motion dependent aerodynamic forces acting on the bluff body could contribute to this. In summary, comprehensive experimental evaluations were conducted to characterize the performance of both baseline GPEHs and improved GPEHs. The baseline GPEH service life can be significantly improved by incorporating an impact bump stop. The improved GPEH design provides a practical solution to harvest electricity from wind-induced vibration.

  7. Large-eddy simulation of a bluff-body stabilized nonpremixed flame

    SciTech Connect

    Kempf, A.; Lindstedt, R.P. [Thermofluids Division, Department of Mechanical Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Janicka, J. [Chair for Energy and Powerplant Technology, Department of Mechanical Engineering, Darmstadt Technical University, Petersenstr. 30, 64287 Darmstadt (Germany)

    2006-01-01

    Large-eddy simulations have been performed for a turbulent nonpremixed bluff-body stabilized CH{sub 4}:H{sub 2} (50:50 vol.) flame at a Reynolds number of 15,800. The corresponding isothermal flow has also been computed. The Sydney bluff-body burner under consideration has been investigated experimentally by Masri and co-workers, who obtained velocity and scalar statistics. The focus of the current work is on flow and mixing effects with the thermochemistry evaluated using a steady-state laminar flamelet approach. The incompressible (low-Mach-number) governing equations for mass, momentum, and mixture-fraction have been solved on a structured cylindrical grid and resolution effects investigated using up to 3.643x10{sup 6} nodes. The corresponding nonreactive case was resolved by 5.76x10{sup 5} nodes, resulting in a resolution of more than 80% of the turbulence kinetic energy. The reacting case yields a resolution in excess of 75% on the finest grid--arguably sufficient to permit conclusions regarding the accuracy of submodels. Comparisons with experimental data show that for high resolutions comparatively good agreement is obtained for the flow field and for species other than nitric oxide. However, resolution effects are important and results obtained with 4.51x10{sup 5} nodes show that a resolution of less than 70% of the turbulent kinetic energy is insufficient in the context of the Smagorinsky subgrid model combined with the dynamic procedure of Germano. The latter result is consistent with the analysis of Pope.

  8. 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.

  9. 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.

  10. The stratigraphy and environment of deposition of productive Wilcox clays in west central Freestone and southeast Limestone Counties, Texas 

    E-print Network

    Shelvey, Stephanie Anne

    1986-01-01

    C. Mathewson The Wilcox Group of east central Texas in Freestone and Limestone Counties has been known as a sour ce of high plasticity clays that have been used 1n the production of refractories, ceramics, brick, and tile. Productive clay... coincident w1th that contact. A cross section constructed through a portion of the study area shows an erosional Simsboro surface beneath the Calvert Bluff, with subsequent erosion and faulting modifying the topographic expression of the two formations...

  11. A quasi-steady 3 degree-of-freedom model for the determination of the onset of bluff body galloping instability

    NASA Astrophysics Data System (ADS)

    Gjelstrup, H.; Georgakis, C. T.

    2011-10-01

    In this paper, a quasi-steady three degree-of-freedom (3-dof) flow-induced galloping instability model for bluff-bodies is proposed. The proposed model can be applied generally for the prediction of onset of galloping instability due to negative aerodynamic damping of any prismatic compact bluff body in a fluidic medium. The three degrees of freedom refer to the bluff body's two orthogonal displacements perpendicular to its length axis and the rotation about its length axis. The model incorporates inertial coupling between the three degrees of freedom and is capable of estimating the onset of galloping instability due changes in drag, lift and moment, assuming that the bluff body is subject to uniform flow and motion. The changes may be a function of wind angle of attack ( ? ) perpendicular to bluff body's length axis, Reynolds number and a skew wind angle ( ? ) in relation to the length axis of the bluff body. An analytical solution of the instability criterion is obtained by applying the Routh-Hurwitz criterion.

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

    Microsoft Academic Search

    Elsik

    1993-01-01

    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

  13. Simulations of local extinction phenomena in bluff-body stabilized diffusion flames with a Lagrangian reactedness model

    Microsoft Academic Search

    D. Papailiou; P. Koutmos; C. Mavridis; A. Bakrozis

    1999-01-01

    Two-dimensional large-eddy simulations of bluff-body stabilized flames of methane and propane, exhibiting significant finite-rate chemistry effects, are presented. A partial equilibrium\\/two-scalar exponential probability density function (PDF) combustion submodel is applied at the subgrid level. Subgrid scale motions are modelled with a first-order closure employing an anisotropic subgrid eddy-viscosity and two equations for the subgrid turbulent kinetic and scalar energies. Statistical

  14. A RETRAN model of the Calvert Cliffs-1 pressurized water reactor for assessing the safety implications of control systems

    SciTech Connect

    Renier, J P.A.; Smith, O L

    1987-03-01

    The failure mode and effects analysis of Calvert Cliffs-1 identified sequences of events judged sufficiently complex to merit further analysis in detailed dynamic simulations. This report describes the RETRAN model developed for this purpose and the results obtained. The mathematical tool was RETRAN2/Mod3, the latest version of a widely used and extensively validated thermal-hydraulics production code obtained by license agreement with the developer, Electric Power Research Institute, and installed on the ORNL BM-3033 computers. RETRAN2 is based on a first-principles methodology that treats two-phase flow with slip. Thermal equilibrium of phases is assumed except in the pressurizer, where non-equilibrium processes are important and special methodology is used. Heat transfer in solids is obtained from the conventional conduction equation. Point or 1-D kinetics is available for the reactor core. The fundamental methodology is supplemented with a broad list of process submodels that calculate heat transfer coefficients, fluid and metal state properties, choked flow, form and wall friction losses, and other parameters. Also supplied are component submodels for various types of valves and pumps, the latter of which incorporate four-quadrant characteristics for components in which two-phase or reverse flow may be expected, and head versus flow curves for others. Extensive input allows the code to be highly particularized to a specific plant. The major investment in time and manpower occurs in setting up the base case; changes are comparatively easy to implement.

  15. On the stabilization of bluff-body wakes by low-density base bleed

    NASA Astrophysics Data System (ADS)

    Martinez-Bazan, Carlos; Sevilla, Alejandro

    2006-11-01

    Base bleed is a simple and well-known means of stabilizing bluff-body wakes at supercritical Reynolds numbers. In the present research we consider a generalization of previous works by studying the effect of the bleed-to-freestream density ratio, S=?b/??, on the stability properties of the wake behind an axisymmetric, slender body with a blunt trailing edge. Since a lower density in the slow stream is known to inhibit absolute instability, here we restrict our attention to the case of light bleed fluid, S<1. This mechanism is shown to inhibit the wake for values of the bleed coefficient, defined as the bleed-to-freestream velocity ratio Cb=ub/u?, smaller than those obtained in the homogeneous case of S=1. Our approach consists of obtaining the basic, axisymmetric flow by integration of the full set of Navier-Stokes and species conservation equations in cylindrical coordinates, and calculating its linear, local, spatio-temporal stability downstream of the body base. The analysis predicts a critical bleed coefficient Cb^*, which decreases with the density ratio according to the linear law Cb^*˜0.01+0.05, for 0.1<=S<=1.

  16. A note on the stabilization of bluff-body wakes by low density base bleed

    NASA Astrophysics Data System (ADS)

    Sevilla, A.; Martínez-Bazán, C.

    2006-09-01

    Base blowing is a simple and well-known means of stabilizing both two-dimensional and axisymmetric bluff-body wakes at supercritical Reynolds numbers. In the present Brief Communication we consider a generalization of previous works by studying the effect of the bleed-to-freestream density ratio, S =?b/??, on the stability properties of the wake behind an axisymmetric, slender body with a blunt trailing edge. Since a lower density in the slow stream is known to inhibit absolute instability, here we restrict our attention to the case of light bleed fluid, S <1. This mechanism is shown to inhibit the wake for values of the bleed coefficient, defined as the bleed-to-freestream velocity ratio Cb=ub/u?, smaller than those obtained in the homogeneous case of S =1. Our approach consists of obtaining the basic, axisymmetric flow by integration of the full set of Navier-Stokes and species conservation equations in cylindrical coordinates, and calculating its linear, local, spatio-temporal stability downstream of the body base. The analysis predicts a critical bleed coefficient Cb*, which decreases with the density ratio according to the linear law Cb*?0.01+0.05S for 0.1?S?1.

  17. Multi-Point Velocity Correlations in the Wake of a Three-Dimensional Bluff Body

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Glauser, Mark

    2013-11-01

    Three-dimensional bluff-bodies known as turrets are commonly used for housing optical systems on airborne platforms. These geometries generate highly turbulent wakes that decrease the performance of the optical systems and the aircraft. The current experimental study used dynamic suction in both open and closed-loop control configurations to actively control the wake turret. The experiments were carried out at a Reynolds number of 5 × 105, and the flow field was characterized using stereoscopic PIV measurements acquired in the wake of the turret. These data were processed using traditional single-point statistics which showed that the active control system was able to significantly alter the wake of the turret. Using multi-point correlations, turbulent characteristics such as the integral length scale can be calculated. For the turret wake, estimates of the integral length scales were found to be highly dependent upon the region of the flow that was evaluated, especially when comparing the shear layers to the center of the wake. With the application of the active control, the integral length scales were generally found to increase.

  18. Self-excited oscillations in the wake of two-dimensional bluff bodies and their control

    NASA Astrophysics Data System (ADS)

    Schumm, Michael; Berger, Eberhard; Monkewitz, Peter A.

    1994-07-01

    The onset of Karman-vortex shedding is studied experimentally in the wake of different two-dimensional bluff bodies, namely an oblong cylinder, circular cylinders, and plates of rectangular cross section. Different control measures, such as wake heating, transverse body oscillations, and base bleed are investigated. As the steady-periodic Karman shedding has previously been identified as a limit-cycle, i.e. as self-excited oscillations, the experiments are interpreted in the framework of the Stuart-Landau model. The coefficients of the Stuart-Landau equation for the characteristic vortex shedding amplitude, i.e. the linear temporal growth rate, linear frequency, and the Landau constant, are fully determined for the two cylinders and in part for the plate. For this purpose transients are generated by suddenly switching transverse body oscillations or base bleed on or off. The analysis of these transients by a refined method based on complex demodulation provides reliable estimates of the model coefficients and yields an experimental validation of the concept that a global instability mode grows or decays as a whole. Also, it is demonstrated that the coefficients of the Stuart-Landau equation are independent of the experimental technique used to produce the transients.

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

    PubMed

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

    2011-01-01

    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 ?m. 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

  20. On the Euler stage of turbulent separation near the trailing edge of a bluff body

    NASA Astrophysics Data System (ADS)

    Scheichl, Bernhard

    2013-10-01

    A novel self-consistent description of time-mean two-dimensional turbulent-boundary-layer flow separating from a bluff body at arbitrarily large globally formed Reynolds numbers is presented. Contrasting with previous approaches, the theory deals with a sufficient delay of flow detachment or, correspondingly, increase of the turbulence intensity so as to both settle the question of the actual position of separation and trigger a turbulent boundary layer exhibiting a large relative streamwise velocity deficit. At separation, a generic variation of the velocity profile close to the body surface with the third power of the distance from it is detected. The Euler stage resulting from the breakdown of the incident boundary layer and governed by its vorticity is envisaged in detail. Specifically, an analytical solution to the central linear vortex-flow problem could be established. This represents the essential ingredient for the understanding of the multi-layered substructure of the flow more close to the surface, which completes the picture of gross separation at the Euler scale. Most important, the analysis does not resort to any specific turbulence closure. Concerning the canonical situation of circular-cylinder flow, a first comparison between the predicted and publicly available experimentally obtained values of the separation angle is encouraging.

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

    SciTech Connect

    Merci, Bart [Department of Flow, Heat and Combustion Mechanics, Ghent University-UGent, Ghent (Belgium); Roekaerts, Dirk [Department of Multi-Scale Physics, Delft University of Technology, Delft (Netherlands); Naud, Bertrand [CIEMAT, Madrid (Spain); Pope, Stephen B. [Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY (United States)

    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)

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

    SciTech Connect

    Subramanian, V.; Domingo, P.; Vervisch, L. [CORIA-CNRS and INSA de Rouen, Technopole du Madrillet, BP 8, 76801 Saint-Etienne-du-Rouvray (France)

    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)

  3. 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 incorporated into detailed glacier and ice-sheet models of the McMurdo Sound region, a critical area in the Ross Ice Sheet and global climate system.

  4. 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.

  5. Monitoring channel morphology and bluff erosion at two installations of flow-deflecting vanes, North Fish Creek, Wisconsin, 2000-03

    USGS Publications Warehouse

    Fitzpatrick, Faith A.; Peppler, Marie C.; Schwar, Heather E.; Hoopes, John A.; Diebel, Matthew W.

    2005-01-01

    Flow-deflecting vanes were installed in the streambed along two meander bends with eroding bluffs in 2000 and 2001 in the upper main stem of North Fish Creek, a tributary to Lake Superior in Wisconsin. About 45 vanes were arranged in 15 arrays at each site to deflect the flow away from the eroding toe or base of the bluff (outside of a bend) and toward the point bar (inside of a bend). Channel cross-section and bluff-erosion surveys were done and streamflow and stage were measured before, during, and after vane installation to monitor changes in channel morphology and bluff erosion in the context of hydrologic conditions. There were two large floods in the study area in spring 2001 (recurrence interval of approximately 100 years) and in spring 2002 (recurrence intervals of approximately 50 years). Some maintenance and replacement of vanes were needed after the floods. Most of the channel-morphology changes resulted from the large floods, and fewer changes resulted from near-bankfull or at-bankfull flows (one in October 2002 and four in April and May 2003). At the bluff located 16.4 river miles upstream of the creek mouth (site 16.4), the vanes deflected flow and caused the channel to migrate away from the base of the bluff and toward the point bar, allowing sediment to deposit along the bluff base. The 361-foot reach at site 16.4 had a net gain of 6,740 cubic feet of sediment over the entire monitoring period (2000?03). Deposition (10,660 cubic feet) occurred mainly along the base of the bluff in the downstream part of the bend. Erosion occurred at site 16.4 along the streambed, the point bar side of the channel, and along a midchannel bar (1,220, 1,610, and 1,090 cubic feet, respectively). Less channel migration was observed during 2001-03 at another bluff located 12.2 river miles upstream of the creek mouth (site 12.2), which had a net loss of sediment through the 439-foot reach of 2,800 cubic feet over the monitored time period. The main volume of sediment was lost from the bluff toe in the downstream part of the bend (7,100 cubic feet). Monitored channel-morphology changes at site 12.2 were less than at site 16.4, most likely because installation was done after the April 2001 flood, which caused major changes in channel morphology at site 16.4, and because the monitoring period was shorter than at site 16.4. Bluff-erosion data from both sites indicate that mass wasting and block failures from the bluff top occur episodically and will continue to occur for decades or more.

  6. Turbulence effects on the flow and pressure distributions around three-dimensional bluff bodies

    NASA Astrophysics Data System (ADS)

    Sitheeq, Mohamed K.

    Effect of turbulence on the pressure distributions on two surface mounted square prism models, one with dimensions twice the other, are investigated. Mean and fluctuating pressure distributions on the front, side, wake and roof faces of the three-dimensional bluff bodies exposed to a simulated neutral urban boundary layer flow in the wind tunnel are presented. All the measurements were carried out for 0 degree approach wind except for the roof face. For the roof face, measurements were conducted for both 0 and 45 degree wind. Simultaneous pressure measurements at typical locations on the same face of the model as well as on different faces were carried out to obtain pressure correlations. The pressure distributions on the side and roof faces of both models showed reattachment of the flow. The trends of the pressure distributions including the peak pressure distributions were the same for both models. The pressure coefficients for the smaller model was lower than for the taller one due to the different ratios of the heights of model and boundary layer. Side face cross correlation measurements showed clearly side flow reattachment. Smoke flow and sand erosion visualization study also corroborated very well the flow reattachment. From the analysis of pressure spectra, no vortex shedding was observed on the side face. Changing the Reynolds number did not change the small scale content of the turbulence. The characteristics of the boundary layer measured in the wind tunnel were compared with atmospheric data and a model scale of around 1:400 was obtained. A simple cost effective common sample and hold computer controlled data acquisition set-up for simultaneous pressure and velocity measurements was devised. A simple and accurate dynamic calibration technique was developed to determine the optimum upper limit of flat frequency response of pressure transducer-tube systems.

  7. Health assessment for Scrdi - Bluff Road, Columbia, South Carolina, Region 4. CERCLIS No. SCD000622787. Preliminary report

    SciTech Connect

    Not Available

    1989-04-10

    The Bluff Road Site (BRS) is in Columbia, South Carolina. Approximately 7,000 drums containing a wide variety of toxic, flammable and reactive wastes were removed from BRS. Preliminary on-site soil and groundwater sampling results have identified various metals, volatile organic compounds, and pesticides. Maximum concentrations found in pre-remediation groundwater sampling include trichlorofluoromethane, dieldrin, lead, and selenium. Based on available information, the site is considered to be of public health concern because of the risk to human health caused by the possibility of human exposure to hazardous substances.

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

    SciTech Connect

    Chaparro, Andres; Landry, Eric; Cetegen, Baki M. [Mechanical Engineering Department, University of Connecticut, 191 Auditorium Road, Storrs, CT 06269-3139 (United States)

    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)

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

    SciTech Connect

    NONE

    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).

  10. Technology resource document for the assembled chemical weapons assessment environmental impact statement. Vol. 3 : assembled systems for weapons destruction at Pine Bluff Arsenal

    Microsoft Academic Search

    T. Kimmell; S. Folga; G. Frey; J. Molberg; P. Kier; B. Templin; M. Goldberg

    2001-01-01

    This volume of the Technical Resource Document (TRD) for the Environmental Impact Statement (EIS) for the ''Design, Construction and Operation of One or More Pilot Test Facilities for Assembled Chemical Weapons Destruction Technologies at One or More Sites'' (PMACWA 2001g) pertains to the destruction of assembled chemical weapons (ACW) stored in the U.S. Army's unitary chemical stockpile at Pine Bluff

  11. 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.

  12. Calvert Marine Museum

    NSDL National Science Digital Library

    Facility in Solomons, MD, interprets regional paleontology, estuarine ecosystem, maritime history. Natural history exhibits: shark, whale and other fossils; aquariums, displays and outdoor trails introducing life of marshes, oyster bars, the Patuxent River and Chesapeake Bay. Maritime history exhibits include woodcarving and boatbuilding shed, oyster house, lighthouse, and traditional Chesapeake Bay wooden sailing vessel. Educational programs for school groups, Elderhostel and the public include: field trips, lectures, cruises, classes, and demonstrations. Admission and program fees apply.

  13. Calvert: an historical geography 

    E-print Network

    McMillan, Frank N

    1984-01-01

    8, in map pocket). Robertson County includes 877 square miles (Texas Almanac 1981, 357) and the landscape may be described as relatively flat savanna country with gently rolling hills dissected by rivers and creek bottoms. Surface drainage... Antonio Road at Benchley, the landscape is characterized by gently rolling hills. If a right turn is made to the east onto Highway 79 from Hearne the incline is very apparent, and the vista presents an undulating landscape rising to the horizon. As one...

  14. "Frog" Walker & Jim Calvert 

    E-print Network

    Unknown

    2011-08-17

    The purpose of this study was to assess learning in sixth grade students? by gain scores in science and mathematics while participating in the integrative curriculum modules developed by the Partnership for Environmental ...

  15. Technology resource document for the assembled chemical weapons assessment environmental impact statement. Vol. 3 : assembled systems for weapons destruction at Pine Bluff Arsenal.

    SciTech Connect

    Kimmell, T.; Folga, S., Frey, G.; Molberg, J.; Kier, P.; Templin, B.; Goldberg, M.

    2001-05-04

    This volume of the Technical Resource Document (TRD) for the Environmental Impact Statement (EIS) for the ''Design, Construction and Operation of One or More Pilot Test Facilities for Assembled Chemical Weapons Destruction Technologies at One or More Sites'' (PMACWA 2001g) pertains to the destruction of assembled chemical weapons (ACW) stored in the U.S. Army's unitary chemical stockpile at Pine Bluff Arsenal (PBA), located outside Pine Bluff, Arkansas. This volume presents technical and process information on each of the destruction technologies applicable to treatment of the specific ACW stored at PBA. The destruction technologies described are those that have been demonstrated as part of the Assembled Chemical Weapons Assessment (ACWA) selection process (see Volume 1).

  16. 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

    NONE

    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.

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

    SciTech Connect

    Triantafyllidis, A.; Mastorakos, E. [Hopkinson Laboratory, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom); Eggels, R.L.G.M. [Rolls Royce Deutschland, Blankenfelde-Mahlow (Germany)

    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)

  18. 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.

  19. Technical evaluation of the adequacy of station electric distribution systems voltages for the Calvert Cliffs Nuclear Power Plant, Units 1 and 2. Docket Nos. 50-317, 50-318

    SciTech Connect

    Selan, J. C.

    1982-04-09

    This report documents the technical evaluation of the adequacy of the station electric distribution system voltages for the Calvert Cliffs Nuclear Power Plant, Units 1 and 2. The evaluation is to determine if the onsite distribution system in conjunction with the offsite power sources has sufficient capacity to automatically start and operate all Class 1E loads within the equipment voltage ratings under certain conditions established by the Nuclear Regulatory Commission. The analyses submitted demonstrate that adequate voltage will be supplied to the Class 1E equipment under worst case conditions.

  20. 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.

  1. 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, but more complex models that account for 3D effects and the dynamic movements of aerial undulation are required to fully understand the gliding performance of flying snakes. PMID:24477611

  2. Three-dimensional topology and dynamical modelling of vortex shedding from finite surface-mounted bluff bodies

    NASA Astrophysics Data System (ADS)

    Bourgeois, Jason A.

    While the dynamically rich behaviour of fully turbulent wakes is very high dimensional, the most energetic, large scale coherent structures generated through instability processes are typically low dimensional and are thereby conducive to reduced order modeling procedures. These large scale eddies associated with the flow instability have the most anisotropic and geometry dependent topology and act as a source of kinetic energy in the cascade process, making them the most important to characterize. Dissipative small scale structure can then be modelled with reasonable accuracy by traditional means. The present study experimentally educes the coherent structures in the complex three-dimensional wake of a wall-mounted finite square-cross-section cylinder of aspect ratio h/d = 4 and 8 immersed in boundary layers of thickness delta/d = 0.72 and 2.6 at a Reynolds number of 12,000. Coherent structure eduction is carried out using phase averaging and a novel generalized phase averaging technique that incorporates proper orthogonal decomposition (POD) modes that are most important in the nonlinear instability saturation process. Global flow estimation and mode construction is undertaken using linear pressure-POD coefficient correlations, applicable to experimental investigations where practicality demands that subdomains of the global field are measured asynchronously. The large-scale coherent structures of the wakes investigated are analyzed in terms of their topology, their turbulent kinetic energy (amounting to roughly half the total fluctuation energy), and their influence on turbulence production. The educed coherent vortical structures are found to have either full-loop or half-loop topological structure depending on the boundary layer thickness, showing vortical connector strands connecting alternately shed vortices from either side of the obstacle. The structure provides an explanation of the dipole and quadrupole distributions of streamwise vorticity that have previously been observed in these types of three-dimensional wakes. The reduced order nonlinear Galerkin models derived for the dynamics of the coherent structures using the generalized phase average are shown to successfully account for the slow base flow transients, the instability saturation mechanism, and the excitation of the second harmonic modes. KEYWORDS: Full-loop vortex shedding, Half-loop vortex shedding, Finite wall-mounted bluff-bodies, Coherent structures, Trailing vortices, Reduced order modelling, Proper orthogonal decomposition, Linear stochastic estimation, Particle image velocimetry.

  3. 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.

  4. 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.

  5. 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.

  6. Study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from Schrader Bluff Pool, Milne Point Unit, Alaska. [Quarterly] report, January 1, 1993--March 31, 1993

    SciTech Connect

    Sharma, G.D.

    1993-06-01

    The ultimate objective of this three-year research project is to evaluate the performance of the hydrocarbon miscible solvent slug process and to assess the feasibility of this process for improving recovery of heavy oil from Schrader Bluff reservoir. This will be accomplished through measurement of PVT and fluid properties of Schrader Bluff oil, determination of phase behavior of Schrader Bluff oil solvent mixtures, asphaltene precipitation tests, slim tube displacement tests, core flood experiments and reservoir simulation studies. The expected results from this project include: determination of optimum hydrocarbon solvent composition suitable for hydrocarbon miscible solvent slug displacement process, optimum slug sizes of solvent needed, solvent recovery factor, solvent requirements, extent and timing of solvent recycle, displacement and sweep efficiency to be achieved and oil recovery. Work performed during quarter includes preliminary reservoir fluid characterization and multiple contact test runs using equation-of-state (EOS) simulator. Reservoir fluid samples are being acquired from Conoco Inc., and the process is expected to continue through the next quarter. Also, the experimental apparatus for the displacement study was set up.

  7. The lithology, environment of deposition, and reservoir properties of sandstones in the Upper Queen Formation (Guadalupian, Permian) at Concho Bluff Queen Field, Crane County, Texas 

    E-print Network

    Newsom, Douglas Floyd

    1989-01-01

    the best method to detect early signs of bone disease when compaxed to QCT. In the 1960's, researchers expressed optimism xegarding use of the technique of neutron activation analysis to determine trace amounts of chlorine, sodium, calcium, nitrogen... skeleton surrounded by tissue equivalent liquid. The subject was irradiated with 2 MeV neutrons produced from the &Be(d, n) t B reaction, and 14 MeV neutxons produced fmm a Van de Graff positive ion accelemtor (Palmer et aL 1968). 'Ihese studies found...

  8. The lithology, environment of deposition, and reservoir properties of sandstones in the Upper Queen Formation (Guadalupian, Permian) at Concho Bluff Queen Field, Crane County, Texas

    E-print Network

    Newsom, Douglas Floyd

    1989-01-01

    A COMPARISON OF DIFFERING TECHNIQUES FOR THE DEIERMINATION OF MINHbtd. CONTENT IN BONE SAMUEL EVERETI' NARROW III Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the retluitements for the degree... of MASTER OF SCIENCE December 1989 Major Subject: Health Physics A COMPARISON OF DIFFERING TECHNIQUES FOR THE DETERMINATION OF MINERAL CONTENT IN BONE A Thesis by SAMUEL EVERETT NARROW III Apprrved as to style and content by: Gerald A. Schlap...

  9. 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

    Lava channels, tubes and sheets are transport structures that deliver flowing lava to a flow front. The type of structure can vary within a flow field and evolve throughout an eruption. The 18.0 × 1.0 ka Twin Craters lava flow in the Zuni-Bandera lava field provides a unique opportunity to study morphological changes of a lava flow partly attributable to interaction with a topographic obstacle. Facies mapping and airborne image analysis were performed on an area of the Twin Craters flow that includes a network of channels, lava tubes, shatter features, and disrupted pahoehoe flows surrounding a 45 m tall limestone bluff. The bluff is 1000 m long (oriented perpendicular to flow.) The general flow characteristics upstream from the bluff include smooth, lobate pahoehoe flows and a >2.5 km long lava tube (see Samuels et al., this meeting.) Emplacement characteristics change abruptly where the flow encountered the bluff, to include many localized areas of disrupted pahoehoe and several pahoehoe-floored depressions. Each depression is fully or partly surrounded by a raised rim of blocky material up to 4 m higher than the surrounding terrain. The rim is composed of 0.05 - 4 m diameter blocks, some of which form a breccia that is welded by lava, and some of which exhibit original flow textures. The rim-depression features are interpreted as shatter rings based on morphological similarity to those described by Orr (2011.Bul Volcanol.73.335-346) in Hawai';i. Orr suggests that shatter rings develop when fluctuations in the lava supply rate over-pressurize the tube, causing the tube roof to repeatedly uplift and subside. A rim of shattered blocks and breccias remains surrounding the sunken tube roof after the final lava withdraws from the system. One of these depressions in the Twin Craters flow is 240 m wide and includes six mounds of shattered material equal in height to the surrounding undisturbed terrain. Several mounds have depressed centers floored with rubbly pahoehoe. 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.

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

    SciTech Connect

    Elsik, W.C. (MycoStrat Connection, Houston, TX (United States))

    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.

  11. 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.

  12. Wake Instabilities Behind Bluff Bodies

    Microsoft Academic Search

    Michel Provansal

    \\u000a The observation by Bénard of a vortex street in the wake of a circular cylinder has been commonly associated with the stability\\u000a analysis of the double alternate street proposed by von Kármán. After a short historical review of these studies, we present\\u000a the main progress in understanding this instability during the last decade. New experiments and the control of two-dimensional

  13. 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.

  14. Galaxy Formation

    E-print Network

    Eric Gawiser

    2005-12-15

    I summarize current knowledge of galaxy formation with emphasis on the initial conditions provided by the Lambda CDM cosmology, integral constraints from cosmological quantities, and the demographics of high-redshift protogalaxies. Tables are provided summarizing the number density, star formation rate and stellar mass per object, cosmic star formation rate and stellar mass densities, clustering length and typical dark matter halo masses for Lyman break galaxies, Lyman alpha emitting galaxies, Distant red galaxies, Sub-millimeter galaxies, and Damped Lyman alpha absorption systems. I also discuss five key unsolved problems in galaxy formation and prognosticate advances that the near future will bring.

  15. Soil Formation

    NSDL National Science Digital Library

    Humans use soil for their daily needs but do not sufficiently take account of its slow formation and fast loss. Discover the amazing geology of soil formation and the basic rock and soil types.Although soil seems the end product from weathering rocks, it is merely a stage in the gigantic cycle of mineral recycling by the movement of tectonic plates.

  16. Drop Formation

    NSDL National Science Digital Library

    This site from the University of Bristolâ??s Mathematics department contains an explanation of drop formation and its applications. A description of studies of drop separation and its applications in medicine and technology are provided. The site also contains photographs, including a series of images showing the formation of a satellite drop.

  17. PREFERENCE FORMATION

    Microsoft Academic Search

    James N. Druckman; Arthur Lupia

    2000-01-01

    ? Abstract This review concerns political preferences—what they are and where they come from. We begin by documenting the close relationship between processes of preference formation and change. Rather than suddenly appearing, most preferences emerge from interactions between individuals and their environment. This aspect of preference formation poses a concrete challenge: to uncover the mechanics of these interactions in important

  18. Godiva Rim Member: A new stratigraphic unit of the Green River Formation in southwest Wyoming and northwest Colorado. Geology of the Eocene Wasatch, Green River, and Bridger (Washakie) Formations, Greater Green River Basin, Wyoming, Utah, and Colorado. Professional paper

    SciTech Connect

    Roehler, H.W.

    1991-01-01

    The report names and describes the Godiva Rim Member of the Green River Formation in the eastern part of the Washakie basin in southwest Wyoming and the central part of the Sand Wash basin in northwest Colorado. The Godiva Rim Member comprises lithofacies of mixed mudflat and lacustrine origin situated between the overlying lacustrine Laney Member of the Green River Formation and the underlying fluvial Cathedral Bluffs Tongue of the Wasatch Formation. The Godiva Rim Member is laterally equivalent to and grades westward into the LaClede Bed of the Laney Member. The Godiva Rim Member of the Green River Formation was deposited along the southeast margins of Lake Gosiute and is correlated to similar lithologic units that were deposited along the northeast margins of Lake Uinta in the Parachute Creek Member of the Green River Formation. The stratigraphic data presented provide significant evidence that the two lakes were periodically connected around the east end of the Uinta Mountains during the middle Eocene.

  19. Regolith Formation

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about the formation of regolith, the loose fragmental material on the Moon's surface. Learners will engage in a series of hands-on activities comparing and contrasting regolith formation processes on the Moon and on Earth. This activity is in Unit 2 of the Exploring the Moon teachers guide and is designed for use especially, but not exclusively, with the Lunar Sample Disk program.

  20. The lithology, environment of deposition, and reservoir evaluation of sandstones in the Upper Queen Formation (Guadalupian, Permian) at Concho Bluff North and Jennifer Fields, Upton and Ector Counties, Texas

    E-print Network

    Harper, James Broox

    1990-01-01

    (Subsurface) Y T TATES SHELF-EDGE TAN SILL BASIN m re EL ~ t O e Z O Ir Z O lal III oj I- o. ' SEVEN RIVERS OUEEN GRAYBURG SAN ANORES YESO SEVEN RIVERS qh c& Gf'@~'d Cherry Cooyoo T olro ono? Victorio Peoh o~ or CASTILLE BELL...

  1. Paleomagnetic and rock magnetic evidence for a secondary yet early magnetization in large sandstone pipes and host Late Middle Jurassic (Callovian) Summerville Formation and Bluff Sandstone near Mesita, west central New Mexico

    Microsoft Academic Search

    John W. Geissman; Stephen S. Harlan

    2004-01-01

    Processes responsible for the acquisition of ancient yet secondary magnetizations are important facets of the geologic history of rocks and, when the age of such magnetizations can be estimated with confidence, provide useful information on the ancient geomagnetic field. In west central New Mexico near Mesita, on the Colorado Plateau, hematitic sandstone and siltstone beds of the Middle Jurassic (Callovian)

  2. Galaxy formation

    NASA Technical Reports Server (NTRS)

    Silk, J.

    1984-01-01

    Implications of the isotropy of the cosmic microwave background on large and small angular scales for galaxy formation are reviewed. In primeval adiabatic fluctuations, a universe dominated by cold, weakly interacting nonbaryonic matter, e.g., the massive photino is postulated. A possible signature of photino annihilation in our galactic halo involves production of cosmic ray antiprotons. If the density is near its closure value, it is necessary to invoke a biasing mechanism for suppressing galaxy formation throughout most of the universe in order to reconcile the dark matter density with the lower astronomical determinations of the mean cosmological density. A mechanism utilizing the onset of primordial massive star formation to strip gaseous protogalaxies is described. Only the densest, early collapsing systems form luminous galaxies.

  3. Planet formation

    Microsoft Academic Search

    Jack J. Lissauer

    1993-01-01

    Models of planetary formation are developed using the present single example of a planetary system, supplemented by limited astrophysical observations of star-forming regions and circumstellar disks. The solar nebula theory and the planetesimal hypothesis are discussed. The latter is found to provide a viable theory of the growth of the terrestrial planets, the cores of the giant planets, and the

  4. Galaxy formation

    PubMed Central

    Peebles, P. J. E.

    1998-01-01

    It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z ? 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation. PMID:9419326

  5. Planet Formation

    Microsoft Academic Search

    Thomas Quinn

    2005-01-01

    Motivating the study of planet formation is not difficult for any curious audience. One of the fundamental human questions\\u000a is that of origins: “where did I come from?„. Breaking this down into constituents produces a series of questions. How did\\u000a the Universe begin? How did stars form? How did planets form? How did life begin? How did intelligent life develop?

  6. Amphiplex Formation

    NASA Astrophysics Data System (ADS)

    Petersen, Shannon; Laaser, Jennifer; Lodge, Timothy

    2015-03-01

    Polymer-micelle complexes are currently under heavy investigation due to their potential applications in targeted drug delivery and gene therapy, yet the dynamics of the complex formation is still relatively unstudied. By varying the ratios of poly(styrene sulfonate) chains and cationic poly(dimethylaminoethyl methacrylate)-b-poly(styrene) micelles and the ionic strength of the system, we created a variety of complex configurations of different sizes and charges. The complexes were characterized dynamic light scattering and zeta potential measurements which provided information regarding the hydrodynamic radius, distribution of sizes, and effective charge.

  7. Ground-water hydrogeology and geochemistry of a reclaimed lignite surface mine 

    E-print Network

    Pollock, Clifford Ralph

    1982-01-01

    ' (HeadWf Department) August 1982 ABSTRACT Ground-Water Hydrogeology and Geochemistry of a Reclaimed Lignite Surface Mine (August 1982) Clifford Ralph Pollock, B. S. , Colorado School of Mines Chairman of Advisory Committee: Dr. Christopher C... in intermediate-depth Calvert Bluff sand aquifers. ACKNOWLEDGMENTS I would like to thank the members of my thesis committee, Dr. Wayne A. Dunlap, Dr, Steven J. Fritz and Dr. Brann Johnson, for their support, helpful suggestions and critical review of my...

  8. Formation Scenarios

    E-print Network

    Rosemary F. G. Wyse

    1999-11-18

    I discuss various proposed formation scenarios for the metal-poor components of the Milky Way Galaxy, emphasising the stellar halo and the thick disk. Interactions and accretion played a significant role in Galactic evolution, in particular at earlier epochs. The present observations favour a scenario by which the thick disk formed through the heating of a pre-existing thin stellar disk, with the heating mechanism being the merging of a satellite galaxy. A remnant `moving group' of the satellite would provide strong support for this scenario, and may have been detected. The field stars in the stellar halo probably formed in early small-scale star-forming regions, which subsequently disrupted. Late accretion is not important for the bulk of the stellar halo. The stellar initial mass function shows no evidence of variations, and indeed shows evidence of being invariant, even in companion satellite galaxies.

  9. A model for heavy mineral deposit formation within Pleistocene to Holocene shoreline sequences in Georgia

    SciTech Connect

    Cocker, M.D. (Georgia Geologic Survey, Atlanta, GA (United States))

    1993-03-01

    The forms and locations of heavy mineral (HM) deposits, and the geomorphologies and HM suites of the six major Pleistocene paleobarrier island complexes on the Georgia coastal plain and the Holocene shoreline deposits may be the result of physical conditions prevalent during the development of two distinct shoreline sequences. The older Wicomico, Penholoway and Talbot complexes are typified by large, linear, undissected sand bodies and long, linear HM deposits and may have been strongly influenced by a greater sediment supply, a wave-dominated energy regime, and a steeper continental shelf than the younger Pamlico, Princess Anne, Silver Bluff and Holocene complexes. The younger complexes which consist of small, stubby and complexly dissected sand bodies may be the result of a tidal dominated energy regime and a more restricted sediment source. In the younger complexes, HM deposits are short and stubby and are commonly located immediately south of a source river. These relations indicate that only a relatively minor amount of longshore transport has occurred. Location of the HM deposits in the older shoreline sequences at a considerably greater distance south of a source river indicates that a greater degree of transport was involved. The development of stronger and more consistent longshore currents and winds during the earlier part of the Pleistocene may account for the differences in sediment transport and HM deposit formation in the older shoreline sequences. These physical differences may be related to the steeper continental shelf and different climatic conditions during the warmer, interglacial period.

  10. Water-Quality Data, 1999-2005, and Ground-Water Level Data, 2004-2005, for McBaine Bottoms, Including the Eagle Bluffs Conservation Area, Columbia, Missouri

    USGS Publications Warehouse

    Smith, Brenda J.; Richards, Joseph M.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the city of Columbia, Missouri, and the Missouri Department of Conservation, collected ground-water quality data from June 1999 through August 2005, surface-water quality data from August 1999 through August 2003, and water-level data from February 2004 through August 2005 in McBaine Bottoms, southwest of Columbia. McBaine Bottoms, adjacent to the Missouri River, is the location of the municipal-supply well field for the city of Columbia, the city of Columbia wastewater-treatment wetlands, and the Missouri Department of Conservation Eagle Bluffs Conservation Area. This report presents water-quality data, which include water-quality analyses of samples collected from 36 water-quality sampling sites (31 were wells and 5 were surface-water sites), and ground-water level data, which include water-level measurements from more than 80 wells. Water samples were analyzed for physical properties, inorganic chemical constituents, nutrients, and dissolved iron. Selected samples were analyzed for trace elements, wastewater organic compounds, and pesticides. In samples from monitoring wells, chloride concentrations ranged from 2.41 to 259 mg/L (milligrams per liter), sodium concentrations ranged from 1.08 to 175 mg/L, and sulfate concentrations ranged from less than 0.2 to 271 mg/L (all concentrations were dissolved). Dissolved nitrite plus nitrate as nitrogen concentrations ranged from less than 0.05 to 0.46 mg/L. Total phosphorous concentrations ranged from less than 0.04 to 1.68 mg/L, dissolved phosphorous concentrations ranged from less than 0.04 to 1.50 mg/L, and dissolved orthophosphorous concentrations ranged from less than 0.01 to 1.83 mg/L. Dissolved iron concentrations ranged from less than 6 to 42,900 g/L (micrograms per liter). Dissolved arsenic concentrations in samples from two monitoring wells ranged from 11 to 37 g/L. In samples from surface-water sampling sites, chloride concentrations ranged from 8.67 to 289 mg/L, sodium concentrations ranged from 6.18 to 219 mg/L, and sulfate concentrations ranged from 33.4 to 119 mg/L. All of the minimum concentrations were detected in samples from Perche Creek. Dissolved nitrite plus nitrate as nitrogen concentrations ranged from less than 0.05 to 1.53 mg/L. Total phosphorous concentrations ranged from 0.07 to 3.06 mg/L, dissolved phosphorous concentrations ranged from less than 0.05 to 2.88 mg/L, and dissolved orthophosphorous concentrations ranged from less than 0.01 to 2.86 mg/L. Most of the maximum concentrations were detected in samples from the city outflow. More than 35 wastewater organic compounds and pesticides were detected in samples from the city outflow. However, most concentrations were estimated or their presence verified, but not quantified. Water levels in monitoring wells ranged from 548.54 to 576.55 ft (feet) above the National Geodetic Vertical Datum of 1929 (NGVD 29). The difference in water levels from February 2004 to August 2005 ranged from 0.13 ft to 10.97 ft.

  11. Pattern Formation

    NASA Astrophysics Data System (ADS)

    Hoyle, Rebecca

    2006-03-01

    From the stripes of a zebra and the spots on a leopard's back to the ripples on a sandy beach or desert dune, regular patterns arise everywhere in nature. The appearance and evolution of these phenomena has been a focus of recent research activity across several disciplines. This book provides an introduction to the range of mathematical theory and methods used to analyse and explain these often intricate and beautiful patterns. Bringing together several different approaches, from group theoretic methods to envelope equations and theory of patterns in large-aspect ratio-systems, the book also provides insight behind the selection of one pattern over another. Suitable as an upper-undergraduate textbook for mathematics students or as a fascinating, engaging, and fully illustrated resource for readers in physics and biology, Rebecca Hoyle's book, using a non-partisan approach, unifies a range of techniques used by active researchers in this growing field. Accessible description of the mathematical theory behind fascinating pattern formation in areas such as biology, physics and materials science Collects recent research for the first time in an upper level textbook Features a number of exercises - with solutions online - and worked examples

  12. CO2 Sequestration Potential of Texas Low-Rank Coals

    SciTech Connect

    Duane A. McVay; Walter B. Ayers Jr; Jerry L. Jensen

    2006-07-01

    The objectives of this project are to evaluate the feasibility of carbon dioxide (CO{sub 2}) sequestration in Texas low-rank coals and to determine the potential for enhanced coalbed methane (ECBM) recovery as an added benefit of sequestration. The main objectives for this reporting period were to (1) estimate the potential for CO{sub 2} sequestration in, and methane production from, low-rank coals of the Lower Calvert Bluff Formation of the Wilcox Group in the east-central Texas region, (2) quantify uncertainty associated with these estimates, (3) conduct reservoir and economic analyses of CO{sub 2} sequestration and ECBM production using horizontal wells, and (4) compare the results with those obtained from previous studies of vertical wells. To estimate the total volumes of CO{sub 2} that may be sequestered in, and total volumes of methane that can be produced from, the Wilcox Group low-rank coals in east-central Texas, we used data provided by Anadarko Petroleum Corporation, data obtained during this research, and results of probabilistic simulation modeling studies we conducted. For the analysis, we applied our base-case coal seam characteristics to a 2,930-mi{sup 2} (1,875,200-ac) area where Calvert Bluff coal seams range between 4,000 and 6,200 ft deep. Results of the probabilistic analysis indicate that potential CO{sub 2} sequestration capacity of the coals ranges between 27.2 and 49.2 Tcf (1.57 and 2.69 billion tons), with a mean value of 38 Tcf (2.2 billion tons), assuming a 72.4% injection efficiency. Estimates of recoverable methane resources, assuming a 71.3% recovery factor, range between 6.3 and 13.6 Tcf, with a mean of 9.8 Tcf. As part of the technology transfer for this project, we presented the paper SPE 100584 at the 2006 SPE Gas Technology Symposium held in Calgary, Alberta, Canada, on May 15-18, 2006. Also, we submitted an abstract to be considered for inclusion in a special volume dedicated to CO{sub 2} sequestration in geologic media, which is planned for publication by the American Association of Petroleum Geologists.

  13. Formate Formation and Formate Conversion in Biological Fuels Production

    PubMed Central

    Crable, Bryan R.; Plugge, Caroline M.; McInerney, Michael J.; Stams, Alfons J. M.

    2011-01-01

    Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production. PMID:21687599

  14. Paleosols and paleoenvironments of the middle Miocene, Maboko Formation, Kenya.

    PubMed

    Retallack, Gregory J; Wynn, Jonathan G; Benefit, Brenda R; Mccrossin, Monte L

    2002-06-01

    The middle Miocene (15 Ma) Maboko Formation of Maboko Island and Majiwa Bluffs, southwestern Kenya, has yielded abundant fossils of the earliest known cercopithecoid monkey (Victoriapithecus macinnesi), and of a kenyapithecine hominoid (Kenyapithecus africanus), as well as rare proconsuline (Simiolus leakeyorum, cf. Limnopithecus evansi) and oreopithecine apes (Mabokopithecus clarki, M. pickfordi), and galagids (Komba winamensis). Specific habitat preferences can be interpreted from large collections of primate fossils in different kinds of paleosols (pedotypes). Fossiliferous drab-colored paleosols with iron-manganese nodules (Yom pedotype) are like modern soils of seasonally waterlogged depressions (dambo). Their crumb structure and abundant fine root-traces, as well as scattered large calcareous rhizoconcretions indicate former vegetation of seasonally wet, wooded grassland. Other fossiliferous paleosols are evidence of nyika bushland (Ratong), and early-successional riparian woodland (Dhero). No fossils were found in Mogo paleosols interpreted as saline scrub soils. Very shallow calcic horizons (in Yom, Ratong, and Mogo paleosols) and Na-montmorillonite (in Mogo) are evidence of dry paleoclimate (300-500 mm MAP=mean annual precipitation). This is the driest paleoclimate and most open vegetation yet inferred as a habitat for any Kenyan Miocene apes or monkeys. Victoriapithecus was abundant in dambo wooded grassland (Yom) and riparian woodland (Dhero), a distribution like that of modern vervet monkeys. Kenyapithecus ranged through all these paleosols, but was the most common primate in nyika bushland paleosols (Ratong), comparable to baboons and macaques today. Mabokopithecus was virtually restricted to riparian woodland paleosols (Dhero), and Simiolus had a similar, but marginally wider, distribution. Habitat preferences of Mabokopithecus and Simiolus were like those of modern colobus monkeys and mangabeys. A single specimen of Komba was found in dambo wooded grassland paleosol (Yom), a habitat more like that of the living Senegal bushbaby than of rainforest galagids. A shift to non-forest habitats may explain the terrestrial adaptations of Victoriapithecus, basal to the cercopithecid radiation, and of Kenyapithecus, basal to the hominoid radiation. Both taxa are distinct from earlier Miocene arboreal proconsulines, oreopithecines and galagids. PMID:12069506

  15. Hydrologic and geochemical data for the Big Brown lignite mine area, Freestone County, Texas

    USGS Publications Warehouse

    Dorsey, M.E.

    1985-01-01

    Lignite mining in east and east-central Texas is increasing in response to increased energy needs throughout the State. Associated with the increase in mining activities is a greater need to know the effects of mining activities on the water quantity and quality of near surface aquifers. The near surface lignite beds mined at the Big Brown Lignite Mine are from the Calvert Bluff Formation of the Wilcox Group of Eocene age, which is a minor aquifer generally having water suitable for all uses, in eastern Freestone County, Texas. One of the potential hydrologic effects of surface coal mining is a change in the quality of groundwater associated with replacement of aquifer materials by mine spoils. The purpose of this report is to compile and categorize geologic, mineralogic, geochemical, and hydrologic data for the Big Brown Lignite Mine and surrounding area in east-central Texas. Included are results of paste-extract analyses, constituent concentrations in water from batch-mixing experiments, sulfur analyses, and minerals or mineral groups detected by X-ray diffraction in 12 spoil material samples collected from 3 locations at the mine site. Also, common-constituent and trace-constituent concentrations in water from eight selected wells, located updip and downdip from the mine, are presented. Dissolved solids concentrations in water from batch-mixing experiments vary from 12 to 908 mg/L. Water from selected wells contains dissolved solids concentrations ranging from 75 to 510 mg/L. (Author 's abstract)

  16. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2011-02-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  17. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2009-01-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  18. Humidity effects on photochemical aerosol formation in the SO 2-NO-C 3H 6-air system

    NASA Astrophysics Data System (ADS)

    Izumi, Katsuyuki; Mizuochi, Motoyuki; Murano, Kentaro; Fukuyama, Tsutomu

    In order to investigate the effects of humidity on the gas-phase oxidation of SO 2 in polluted air and on the subsequent aerosol formation process, photoirradiation experiments were carried out by means of a 4-m 3 chamber, in which mixtures containing SO 2, NO and C 3H 6 with concentrations in the ppm range were exposed to simulated solar radiation in different relative humidity (r.h.) conditions. The total amount of oxidized SO 2 was quantified from the SO 42- yield determined by the chemical analysis of the aerosol product, and a part due to the oxidation by the OH radical was evaluated by estimating the OH concentration from the decay rate of C 3H 6. The remaining part was assigned to the oxidation by the Criegee intermediate, as it had a good correlation with the progress of the O 3 + C 3H 6 reaction. The contributions of the two oxidizing species to the total conversion and the oxidation rate of SO 2 were measured as functions of r.h. As a result, experimental evidence was obtained for the prediction of Calvert and Stockwell's (1983, Envir. Sci. Technol. 17, 428A-443A) simulation that the oxidation due to the Criegee intermediate was retarded by the increase in humidity. The OH contribution, on the other hand, was almost independent of r.h. It was observed consequently that the total oxidized amount of SO 2 considerably decreased as r.h. was higher. The humidity effect on the aerosol formation process was found to be more complicated than the effect on the gas-phase chemistry. The maximum rate of increase in the particle number concentration rose linearly with increasing r.h., but the number concentration itself measured at its maximum or at the end of the irradiation reached a ceiling value around r.h. = 30% and went down for higher r.h. The average panicle size in the final stage of the reaction showed a minimum around the same r.h. at which the number concentration was maximum. The H 2SO 4 concentration in the mist particles, however, decreased monotonically as r.h. got higher. It was suggested that these different responses against the increase in humidity resulted from the cooperation of several processes such as the H 2SO 4 monomer formation, the H 2O condensation, the particle coagulation, etc., which had different dependences on r.h.

  19. Scenarios for galaxy formation

    NASA Technical Reports Server (NTRS)

    Silk, Joseph

    1997-01-01

    The gravitational instability theory and its application to the origin of large scale structure are reviewed. The modeling of galaxy formation is described, from forwards and backwards perspectives. The emphasis is on the interactions between stellar and galactic formation.

  20. Star Formation in Galaxies

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Topics addressed include: star formation; galactic infrared emission; molecular clouds; OB star luminosity; dust grains; IRAS observations; galactic disks; stellar formation in Magellanic clouds; irregular galaxies; spiral galaxies; starbursts; morphology of galactic centers; and far-infrared observations.

  1. The formation of galaxies

    NASA Technical Reports Server (NTRS)

    Efstathiou, G.; Silk, J.

    1983-01-01

    Current models of galaxy formation are examined in a review of recent observational and theoretical studies. Observational data on elliptical galaxies, disk galaxies, luminosity functions, clustering, and angular fluctuations in the cosmic microwave background are summarized. Theoretical aspects discussed include the origin and early evolution of small fluctuations, matter and radiation fluctuations, the formation of large-scale structure, dissipationless galaxy formation, galaxy mergers, dissipational galaxy formation, and the implications of particle physics (GUTs, massive neutrinos, and gravitinos) for cosmology.

  2. Portable Executable File Format

    Microsoft Academic Search

    Abhishek Singh

    PE stands for 'portable executable' file format. As the name suggests, the format can be portable across all the 32-bit operating\\u000a system and can be executed on any version of windows. The format is also being used by 32-bit dlls and Windows NT device derivers.\\u000a The WINNT.H header file defines the structure definition representation for the PE file format.\\u000a \\u000a Understanding

  3. When Efficient Star Formation Drives Cluster Formation

    Microsoft Academic Search

    G. Parmentier; U. Fritze

    2009-01-01

    We investigate the impact of the star-formation efficiency (SFE) in cluster-forming cores (i.e., local SFE) on the evolution of mass in star clusters (SCs) over the age range 1-100 Myr, when SCs undergo their infant weight-loss\\/mortality phase. Our model builds on the N-body simulation grid of Baumgardt & Kroupa. Assuming a constant formation rate of gas-embedded clusters and a weak

  4. Calvert versus Carroll: The Quitrent Controversy between Maryland's Founding Families

    Microsoft Academic Search

    Garrett Power

    2005-01-01

    This essay examines the historical background behind the 1826 U.S. Supreme Court case of Cassell v. Carroll. The legal merits in the case concerned arcane questions of feudal property law which the Court avoided and left unanswered. Today the case is of little jurisprudential significance. It is the historical record behind Cassell v. Carroll that tells a story that continues

  5. Estuarine stream piracy: Calvert County US Atlantic coastal plain

    SciTech Connect

    Vogt, P.R. (Naval Research Lab., Washington, DC (United States))

    1991-07-01

    The topography of Maryland's western shore of the Chesapeake Bay shows that five steams now flowing eastward into the bay comprise the pirated (and inverted) headwaters of streams previously flowing westward from a varnished Pliocene upland now occupied by the central Chesapeake. Estuarine shoreline erosion during Pleistocene interglaciations removed the upland, exposing the upper reaches of west-flowing stream valleys. Headward (westward) erosion by east-flowing streams then occurred along existing valleys, facilitated by steep eastward gradients and easily eroded valley-floor sediments. Stream inversion may be more common than previously recognized, since any eroding shoreline causes consumption of seaward-draining watershed and steepening of gradients, thus setting the stage for eventual stream inversion.

  6. Globular Cluster Formation

    E-print Network

    Keith M. Ashman

    2002-10-27

    The discovery of young globular clusters in merging galaxies and other environments provides an opportunity to study directly the process of globular cluster formation. Empirically it appears that globular cluster formation occurs preferentially in regions in which star formation occurs at a high rate and efficiency. Further, the interstellar medium in such regions is likely to be at a higher pressure than less active star-forming environments. An additional observational clue to the globular cluster formation process is that young globular clusters have little or no mass-radius relationship. In this paper I argue that high pressure and high star-formation efficiency are responsible for current globular cluster formation. I suggest that the precursors to globular clusters are molecular clouds and that the mass-radius relationship exhibited by such clouds is wiped out by a variable star formation efficiency.

  7. 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

    (2) Persons desiring to transit the area of the security zone may contact the Captain of the Port at telephone number 410-576-2693 or on VHF channel 16 (156.8 MHz) to seek permission to transit the...

  8. 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

    ...available online in the NRC Library at http://www.nrc...organized under the laws of France, which is, in turn, a wholly-owned...subsidiary of Electricite de France SA, a French limited company...electronically from the NRC Library on the NRC Web site...

  9. 76 FR 1469 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-10

    ...licensee to use M5, an advanced alloy fuel cladding material for pressurized-water...that contain fuel consisting of uranium oxide pellets enclosed in zircaloy...cladding material. M5 is an alloy comprised primarily of zirconium...composition of the M5 advanced alloy differs from the...

  10. Stratigraphy and depositional environments of the upper Pleistocene Chemehuevi Formation along the lower Colorado River

    USGS Publications Warehouse

    Malmon, Daniel V.; Howard, Keith A.; House, P. Kyle; Lundstrom, Scott C.; Pearthree, Philip A.; Sarna-Wojcicki, Andrei M.; Wan, Elmira; Wahl, David B.

    2011-01-01

    The Chemehuevi Formation forms a conspicuous, widespread, and correlative set of nonmarine sediments lining the valleys of the Colorado River and several of its larger tributaries in the Basin and Range geologic province. These sediments have been examined by geologists since J. S. Newberry visited the region in 1857 and are widely cited in the geologic literature; however their origin remains unresolved and their stratigraphic context has been confused by inconsistent nomenclature and by conflicting interpretations of their origin. This is one of the most prominent stratigraphic units along the river below the Grand Canyon, and the formation records an important event or set of events in the history of the Colorado River. Here we summarize what is known about these deposits throughout their range, present new stratigraphic, sedimentologic, topographic, and tephrochronologic data, and formally define them as a lithostratigraphic unit. The Chemehuevi Formation consists primarily of a bluff-forming mud facies, consisting of gypsum-bearing, horizontally bedded sand, silt, and clay, and a slope-forming sand facies containing poorly bedded, well sorted, quartz rich sand and scattered gravel. The sedimentary characteristics and fossil assemblages of the two facies types suggest that they were deposited in flood plain and channel environments, respectively. In addition to these two primary facies, we identify three other mappable facies in the formation: a thick-bedded rhythmite facies, now drowned by Lake Mead; a valley-margin facies containing abundant locally derived sediment; and several tributary facies consisting of mixed fluvial and lacustrine deposits in the lower parts of major tributary valleys. Observations from the subsurface and at outcrops near the elevation of the modern flood plain suggest that the formation also contains a regional basal gravel member. Surveys of numerous outcrops using high-precision GPS demonstrate that although the sand facies commonly overlies the mud facies where the two are found together, contacts between the two occur over a range in elevation, and as a consequence, the sand and mud facies are similarly distributed both horizontally and vertically throughout the valley. Collectively, the outcrops of the formation lie below a smooth elevation envelope that slopes 50 percent more steeply than the historic (pre-Hoover Dam) valley, from nearly 150 m above the historic flood plain near the mouth of the Grand Canyon to less than 30 m above the flood plain at the head of the flood plain near Yuma, Arizona. The steepness of the valley at the peak of aggradation probably represents a depositional slope. Layers of fine grained volcanic tephra have been found below and within the Chemehuevi Formation at five widely separated sites, one of which is now submerged beneath Lake Mead. Major element geochemistry of glass shards from the four accessible tephra sites were analyzed. Three of the sampled tephra layers are interbedded within the Chemehuevi Formation, and a fourth tephra conformably underlies the formation. The three interbedded tephra layers are similar enough to one another that they are probably from the same eruptive unit, hereafter referred to as the Monkey Rock tephra bed. The other sample, which locally underlies the formation, is similar enough to the Monkey Rock tephra bed to suggest it is from the same volcanic source area; however, it may not be from the same eruption, and thus may not be the same age. On the basis of the stratigraphic contexts of chemically similar tephra layers found elsewhere in the Basin and Range, we suspect that the source area is the Mammoth Mountain dome complex in Long Valley, east-central California. Two samples of proximal Mammoth Mountain pumice were analyzed and produced geochemical signatures similar to all four of the Chemehuevi Formation tephra, supporting Mammoth Mountain as a possible source area. The Mammoth Mountain volcanic center produced eruptions between about 111±2 and 57±2 ka and was most active in the later part of this time

  11. Differentiated Teacher Evaluation.

    ERIC Educational Resources Information Center

    Glatthorn, Allan A.; Holler, Richard L.

    1987-01-01

    Calvert County School District, Maryland, has developed a differentiated teacher evaluation system that promotes collaboration among supervisors and administrators in rating teacher performance. Methods involve informal observation, rating observation, and nonrating observation. Implementation is accompanied by extensive formative evaluation by…

  12. Data format translation routines

    SciTech Connect

    Burris, R.D.

    1981-02-01

    To enable the effective connection of several dissimilar computers into a network, modification of the data being passed from one computer to another may become necessary. This document describes a package of routines which permit the translation of data in PDP-8 formats to PDP-11 or DECsystem-10 formats or from PDP-11 format to DECsystem-10 format. Additional routines are described which permit the effective use of the translation routines in the environment of the Fusion Energy Division (FED) network and the Elmo Bumpy Torus (EBT) data base.

  13. Flash Open File Format

    NSDL National Science Digital Library

    Macromedia has released the file format specification for its Flash (discussed in the April 11, 1997 Scout Report) multimedia web tool. Flash allows web developers to create vector based graphics and animation. By making the format (.swf) available, Macromedia hopes to establish it as a standard for vector graphics and animation. The company claims it will "submit the format specification to a recognized Internet standards organization." In addition to providing the file format specification, the site provides Flash related news releases, a Flash FAQ, and a vector graphics white paper.

  14. layout formats sectioneight

    E-print Network

    Derisi, Joseph

    layout formats 69 sectioneight contents about the grid..........................................................................................................70 layout and the grid POSSIBLE SUB-HEAD POSITION UCSF basic brochure layout structure University of California San Francisco

  15. When efficient star formation drives cluster formation

    E-print Network

    G. Parmentier; U. Fritze

    2008-09-14

    We investigate the impact of the star formation efficiency in cluster forming cores on the evolution of the mass in star clusters over the age range 1-100Myr, when star clusters undergo their infant weight-loss/mortality phase. Assuming a constant formation rate of gas-embedded clusters and a weak tidal field, we show that the ratio between the total mass in stars bound to the clusters over that age range and the total mass in stars initially formed in gas-embedded clusters is a strongly increasing function of the averaged local SFE, with little influence from any assumed core mass-radius relation. Our results suggest that, for young starbursts with estimated tidal field strength and known recent star formation history, observed cluster-to-star mass ratios, once corrected for the undetected clusters, constitute promising probes of the local SFE, without the need of resorting to gas mass estimates. Similarly, the mass ratio of stars which remain in bound clusters at the end of the infant mortality/weight-loss phase depends sensitively on the mean local SFE, although the impacts of the width of the SFE distribution function and of the core mass-radius relation require more careful assessment in this case. Following the recent finding by Bastian (2008) that galaxies form, on the average, 8% of their stars in bound clusters regardless of their star formation rate, we raise the hypothesis that star formation in the present-day Universe is characterized by a near-universal distribution for the local SFE. A related potential application of our model consists in tracing the evolution of the local SFE over cosmological lookback times by comparing the age distribution of the total mass in star clusters to that in field stars. We describe model aspects which are still to be worked out before achieving this goal.

  16. Star formation Simon Goodwin

    E-print Network

    Crowther, Paul

    Star formation Simon Goodwin Dept Physics & Astronomy, University of Sheffield, Hounsfield Road, Sheffield, S3 7RH, UK. s.goodwin@sheffield.ac.uk 1 Abstract Stars are one of the most important consituents of the Universe, and understanding their formation is crucial to many areas of astrophysics. Stars form from dense

  17. TRIHALOMETHANE REMOVAL AND FORMATION

    E-print Network

    District of Columbia, University of the

    --------------------------------------------------- 53 iii #12;Introduction Drinking water is chlorinated to inactivate the bacteria in order to prevent in water to give rise to haloform reactions and produce THMs. The organics that lead to the formation#12;TRIHALOMETHANE REMOVAL AND FORMATION MECHANISM IN WATER R.C. Chawla, M. M. Varma, A. BaIram, M

  18. Formative Assessment Probes

    ERIC Educational Resources Information Center

    Eberle, Francis; Keeley, Page

    2008-01-01

    Formative assessment probes can be effective tools to help teachers build a bridge between students' initial ideas and scientific ones. In this article, the authors describe how using two formative assessment probes can help teachers determine the extent to which students make similar connections between developing a concept of matter and a…

  19. Factors Affecting Clay Formation

    Microsoft Academic Search

    Isaac Barshad

    1957-01-01

    Barshad's method of calculating clay formation from the chemical analyses of the whole soil, the clay fraction, the nonclay fraction, and the mechanical analysis was applied to a large number of soils to determine the effect of climate, topography, parent material, vegetation and time on al~ount of clay formation. The amount of clay formed from )00 g of the nonclay

  20. Star Formation Ralf Klessen

    E-print Network

    Klessen,Ralf

    need to explain dynamic star formation theory gravity vs. turbulence (and all the rest) examples, green radio: blue Star formation in interacting galaxies: (from the Chandra Webpage) #12;(HST. The Trapezium cluster is only visible in the IR and contains about 2000 newly born stars. Orion molecular cloud

  1. Delayed ettringite formation

    Microsoft Academic Search

    H. F. W Taylor; C Famy; K. L Scrivener

    2001-01-01

    Delayed ettringite formation (DEF) can damage concrete that has experienced a temperature above about 70°C. Claims that slow release of sulfate from the clinker can have a similar effect in concrete not thus heated are unsupported. Chemical and microstructural aspects of DEF are reviewed. Expansion results from formation of ettringite crystals of submicrometre size in the paste, the larger crystals

  2. International Exchange Formats.

    ERIC Educational Resources Information Center

    Hopkinson, Alan

    This paper focuses on the establishment of three standard international formats for the exchange of bibliographic data--UNIMARC, CCF, and the UNISIST Reference Manual--and outlines their common and differing features. The development of the UNIMARC manual as the standard international MARC network exchange format is traced, and its salient…

  3. Star Formation Thresholds

    NASA Astrophysics Data System (ADS)

    Schaye, Joop

    2008-05-01

    To make predictions for the existence of “dark galaxies”, it is necessary to understand what determines whether a gas cloud will form stars. Star formation thresholds are generally explained in terms of the Toomre criterion for gravitational instability. I contrast this theory with the thermo-gravitational instability hypothesis of Schaye (2004), in which star formation is triggered by the formation of a cold gas phase and which predicts a nearly constant surface density threshold. I argue that although the Toomre analysis is useful for the global stability of disc galaxies, it relies on assumptions that break down in the outer regions, where star formation thresholds are observed. The thermo-gravitational instability hypothesis can account for a number of observed phenomena, some of which were thought to be unrelated to star formation thresholds.

  4. Formate production through biocatalysis

    PubMed Central

    Alissandratos, Apostolos; Kim, Hye-Kyung; Easton, Christopher J

    2013-01-01

    The generation of formate from CO2 provides a method for sequestration of this greenhouse gas as well as the production of a valuable commodity chemical and stabilized form of hydrogen fuel. Formate dehydrogenases are enzymes with the potential to catalyze this reaction; however they generally favor the reverse process, i.e., formate oxidation. By contrast, the formate dehydrogenase of the acetogen Clostridium carboxidivorans has been found to preferentially catalyze the reduction of CO2. This is in accord with its natural role to introduce CO2 as a carbon source in the Wood-Ljungdahl pathway. The direction of catalysis derives from the enzyme’s low affinity for formate. This enzyme is therefore an excellent candidate for biotechnological applications aimed at producing formic acid and derivative chemicals from CO2. PMID:23841981

  5. When efficient star formation drives cluster formation

    E-print Network

    Parmentier, G

    2008-01-01

    We investigate the impact of the star formation efficiency in cluster forming cores on the evolution of the mass in star clusters over the age range 1-100Myr, when star clusters undergo their infant weight-loss/mortality phase. Assuming a constant formation rate of gas-embedded clusters and a weak tidal field, we show that the ratio between the total mass in stars bound to the clusters over that age range and the total mass in stars initially formed in gas-embedded clusters is a strongly increasing function of the averaged local SFE, with little influence from any assumed core mass-radius relation. Our results suggest that, for young starbursts with estimated tidal field strength and known recent star formation history, observed cluster-to-star mass ratios, once corrected for the undetected clusters, constitute promising probes of the local SFE, without the need of resorting to gas mass estimates. Similarly, the mass ratio of stars which remain in bound clusters at the end of the infant mortality/weight-loss ...

  6. Urethral seam formation and hypospadias

    Microsoft Academic Search

    Laurence S. Baskin; Ali Erol; Priya Jegatheesan; Yingwu Li; Wenhui Liu; Gerald R. Cunha

    2001-01-01

    Knowledge of the formation of the normal male urethra may elucidate the etiology of hypospadias. We describe urethral formation in the mouse, show the similarities and relevance to human urethral development, and introduce the concept of the epithelial seam formation and remodeling during urethral formation. Three mechanisms may account for epithelial seam formation: (1) epithelial-mesenchymal transformation similar to that described

  7. Formation of Hurricanes

    NSDL National Science Digital Library

    Amber Morgan

    2012-08-10

    This is a picture inquiry based lesson for students to explore the formation of hurricanes. Groups of three students will observe and explain trends found in a picture and share ideas with their peers.

  8. Essays on Network Formation 

    E-print Network

    Mueller, William Graham

    2012-10-19

    This dissertation contains two essays which examine the roles that individual incentives, competition, and information play in network formation. In the first essay, I examine a model in which two competing groups offer ...

  9. Biomarker variations in relation to paleogeography in the Saltos Shale member of the Monterey Formation, Cuyama basin, California

    SciTech Connect

    Lillis, P.G. (Geological Survey, Denver, CO (USA))

    1990-05-01

    The Miocene stratigraphy of the Cuyama basin provides an excellent opportunity to correlate geology with molecular organic geochemistry (e.g., biomartker compounds) because the paleogeography and paleobathymetry of the basin are well constrained by surface and subsurface geologic mapping and detailed micropaleontology. The Monterey Formation is composed of biogenous and terrigenous sediments that accumulated in a deep marine borderland basin adjacent to a Miocene shoreline. the lower member, the Saltos Shale, is predominately terrigenous sediment interbedded with impure carbonates that consist of foraminifera and calcareous nannofossils. The upper member, the Whiterock Bluff Shale, is composed of highly biogenous (siliceous and carbonate) sediments. The biomarker composition of the Saltos Shale is dependent on the relative contributions of planktonic and benthonic organisms, bacteria, and terrigenous organic matter transported from the nearby landmass. A general trend in biomarker distribution is observed in relation to paleogeography (i.e. proximity to shoreline). Pristane/phytane ratios, hopane/sterane ratios, oleanane/hopane ratios, and diasterane/sterane ratios are higher near the shoreline (to the east) because of increased terrigenous input. The more distal western basin sediments contain biomarkers that were predominately derived from marine phytoplankton and bacteria. Submarine fan sediments in the Saltos Shale were deposited in the eastern basin east of the penecontemporaneous Cox fault. Ponding of terrigenous organic matter at the base of slope is reflected by high ratios of pristane/phytane (2.7), oleanane/hopane (0.79), C{sub 29}/C{sub 27} {alpha}{alpha}{alpha}2OR steranes (1.56), and relatively large amounts of waxy n-alkanes (C{sub 27}, C{sub 29}, C{sub 31}). In contrast, the prefan and postfan sediments contain lower concentrations of these terrigenous biomarkers.

  10. Vascular Lumen Formation

    PubMed Central

    Lammert, Eckhard; Axnick, Jennifer

    2012-01-01

    The vascular system developed early in evolution. It is required in large multicellular organisms for the transport of nutrients, oxygen, and waste products to and from tissues. The vascular system is composed of hollow tubes, which have a high level of complexity in vertebrates. Vasculogenesis describes the de novo formation of blood vessels, e.g., aorta formation in vertebrate embryogenesis. In contrast, angiogenesis is the formation of blood vessels from preexisting ones, e.g., sprouting of intersomitic blood vessels from the aorta. Importantly, the lumen of all blood vessels in vertebrates is lined and formed by endothelial cells. In both vasculogenesis and angiogenesis, lumen formation takes place in a cord of endothelial cells. It involves a complex molecular mechanism composed of endothelial cell repulsion at the cell–cell contacts within the endothelial cell cords, junctional rearrangement, and endothelial cell shape change. As the vascular system also participates in the course of many diseases, such as cancer, stroke, and myocardial infarction, it is important to understand and make use of the molecular mechanisms of blood vessel formation to better understand and manipulate the pathomechanisms involved. PMID:22474612

  11. Constraints on Exomoon Formation

    NASA Astrophysics Data System (ADS)

    Nakajima, Miki; Genda, Hidenori; Asphaug, Erik; Ida, Shigeru

    2014-11-01

    It has been widely accepted that the Earth’s moon formed by a giant impact during the late stage of the planetary formation process. The giant impact led to the formation of a debris disk around the Earth from which the Moon accreted. This type of satellite formation is considered to be common not only in the solar system (e.g., the Pluto-Charon system) but also in extrasolar systems (e.g. Ogihara & Ida 2009). However, no detailed research has been conducted on impact-induced exomoon formation. Wada et al. (2006) suggest that a vapor-rich disk is dynamically unstable and that it may not be suitable for moon formation. If this is the case, the mass and composition of a planet may affect the satellite formation process. Here, we show results from giant impact simulations of planets with various masses and compositions. We use the model suggested by Nakajima & Stevenson (2014) to estimate the vapor mass fractions of the disks. We find that the more massive and the more ice-rich the planet is, the higher the vapor mass fraction of the disk becomes. This indicates there is an upper limit of the planetary mass to form an impact-induced moon and the limit depends on the planetary composition. This upper limit is a few Earth masses for a rocky planet, and about an Earth mass for an icy planet. These results are consistent with the models that Earth’s and Pluto’s satellites formed by impacts. Although no exomoon has been detected yet, our model may be used to predict whether an observed terrestrial exoplanet could potentially have one or multiple impact-induced exomoons.

  12. Wotsit's File Format Collection

    NSDL National Science Digital Library

    Wotsit's File Format Collection, provided by Paul Oliver, features a very large number of file formats. These include JPEG image files, wave sound files, Rich Text files, and common database and word-processing files such as Paradox and Wordperfect. Documents collected or linked at the site are primarily either original specifications from the creator or an improved version of the original. All of the specifications are very technical and are directed towards programmers. Users can subscribe to a mailing list for notification of site updates.

  13. Gaussian entanglement of formation

    SciTech Connect

    Wolf, M.M. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, Garching, D-85748 (Germany); Institut fuer Mathematische Physik, Mendelssohnstrasse. 3, D-38106 Braunschweig (Germany); Giedke, G. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, Garching, D-85748 (Germany); Institut fuer Quantenelektronik, ETH Zuerich, Wolfgang-Pauli-Strasse 16, CH-8093 Zurich (Switzerland); Krueger, O.; Werner, R. F. [Institut fuer Mathematische Physik, Mendelssohnstrasse. 3, D-38106 Braunschweig (Germany); Cirac, J.I. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, Garching, D-85748 (Germany)

    2004-05-01

    We introduce a Gaussian version of the entanglement of formation adapted to bipartite Gaussian states by considering decompositions into pure Gaussian states only. We show that this quantity is an entanglement monotone under Gaussian operations and provide a simplified computation for states of arbitrary many modes. For the case of one mode per site the remaining variational problem can be solved analytically. If the considered state is in addition symmetric with respect to interchanging the two modes, we prove additivity of the considered entanglement measure. Moreover, in this case and considering only a single copy, our entanglement measure coincides with the true entanglement of formation.

  14. Formation of Galactic Disks

    E-print Network

    S. Michael Fall

    2002-03-27

    We review progress in understanding the formation of galactic disks in the standard cosmogonic scenario involving gravitational clustering of baryons and dark matter and dissipative collapse of the baryons. This scenario accounts remarkably well for the observed properties of galactic disks if they have retained most of the specific angular momentum they acquired by tidal torques. Early simulations, which included cooling of the gas but not star formation and the associated feedback, indicated instead that most of the angular momentum of the baryons would be transferred to the dark matter. Recent simulations indicate that this angular-momentum problem can be solved partially, and in some cases entirely, by feedback and other effects.

  15. Cave Formation: Kane Cave

    NSDL National Science Digital Library

    This video documents an experiment conducted in Kane Cave, Wyoming, to see if microbes that inhabit the cave could actually be contributing to the cave-formation process. Adapted from a NOVA broadcast, the segment is four minutes and twelve seconds in length.

  16. Formation-flying interferometry

    Microsoft Academic Search

    Oliver P. Lay; Gary H. Blackwood

    2003-01-01

    There are many advantages to space-based interferometry, but monolithic, single-spacecraft platforms set limits on the collecting area and baseline length. These constraints can be overcome by distributing the optical elements of the interferometer over a system of multiple spacecraft flying in precise formation, opening up new realms of angular resolution and sensitivity. While the principles of interferometry are the same

  17. Peculiar Ice Formation

    Microsoft Academic Search

    W. B. Wright

    1906-01-01

    As the question of earth-bearing ice-pillars has been recently raised in your columns (pp. 464, 485), there are one or two points to which I should like to direct attention, as they may be of interest to your readers. While working in company with a colleague on Divis Mountain, Belfast, in 1902, our attention was attracted by the peculiar formation

  18. Wound-Periderm Formation

    Microsoft Academic Search

    Idit Ginzberg

    Herbivores, and particularly chewing insects, cause substantial damage to the plant. In addition to lost tissue, there are great concerns of pathogen invasion and water loss at the site of the attack. One of the plant’s defense strategies is the formation of wound periderm at the boundaries of the invaded or damaged region to isolate it from non-wounded healthy tissue.

  19. Revision lecture Exam format

    E-print Network

    Alechina, Natasha

    1 Revision lecture · Exam format · Some topics: time and space complexity, big-O, hash tables choice, covers the whole course). · The other three out of five are up to you. Multiple choice · Multiple[i/2]; arr1[i+1] = arr[i/2]; } return arr1; } s(n) = 2nc + c Big O · Big O notation is used to classify

  20. Revision lecture Exam format

    E-print Network

    Alechina, Natasha

    1 Revision lecture · Exam format · Some topics: time and space complexity, big-O, hash tables course). · The other three out of five are up to you. Multiple choice · Multiple choice]; arr2[i+1] = arr[i/2]; } return arr1; } s(n) = 2nc + c Big O · Big O notation is used to classify time

  1. Revision lecture Exam format

    E-print Network

    Alechina, Natasha

    1 Revision lecture · Exam format · Some topics: time and space complexity, big-O, hash tables of five are up to you. Multiple choice · Multiple choice is straightforward `select one correct option]; } return arr1; } s(n) = 2nc + c Big O · Big O notation is used to classify time/space growth functions

  2. Formation of Freirian Facilitators.

    ERIC Educational Resources Information Center

    Noble, Phyllis

    This paper is written for people who are already familiar with the philosophy and methodology of Paulo Freire's liberatory education and are interested in creating a formation program for adult education facilitators using his ideas. The author describes the paper as "a collection of thoughts, of things to consider," when organizing such a…

  3. FORMATION OF PHOTOCHEMICAL AEROSOLS

    EPA Science Inventory

    The objective was to develop a better understanding of smog aerosol formation with particular reference to haze in the Southern California area. This study combined laboratory work with ambient air studies. Counting of particles by light scattering was the principle physical tech...

  4. CO2 SEQUESTRATION POTENTIAL OF TEXAS LOW-RANK COALS

    SciTech Connect

    Duane A. McVay; Walter B. Ayers Jr.; Jerry L. Jensen

    2003-10-01

    The objectives of this project are to evaluate the feasibility of carbon dioxide (CO{sub 2}) sequestration in Texas low-rank coals and to determine the potential for enhanced coalbed methane (CBM) recovery as an added benefit of sequestration. The main objective for this reporting period was to further characterize the three areas selected as potential CO{sub 2} sequestration sites. Well-log data are critical for defining depth, thickness, number, and grouping of coal seams at the proposed sequestration sites. Thus, we purchased 12 hardcopy well logs (in addition to 15 well logs obtained during previous quarter) from a commercial source and digitized them to make coal-occurrence maps and cross sections. Detailed correlation of coal zones is important for reservoir analysis and modeling. Thus, we correlated and mapped Wilcox Group subdivisions--the Hooper, Simsboro and Calvert Bluff formations, as well as the coal-bearing intervals of the Yegua and Jackson formations in well logs. To assess cleat properties and describe coal characteristics, we made field trips to Big Brown and Martin Lake coal mines. This quarter we also received CO{sub 2} and methane sorption analyses of the Sandow Mine samples, and we are assessing the results. GEM, a compositional simulator developed by the Computer Modeling Group (CMG), was selected for performing the CO{sub 2} sequestration and enhanced CBM modeling tasks for this project. This software was used to conduct preliminary CO{sub 2} sequestration and methane production simulations in a 5-spot injection pattern. We are continuing to pursue a cooperative agreement with Anadarko Petroleum, which has already acquired significant relevant data near one of our potential sequestration sites.

  5. Pattern formation during vasculogenesis

    PubMed Central

    Czirok, Andras; Little, Charles D.

    2012-01-01

    Vasculogenesis, the assembly of the first vascular network, is an intriguing developmental process that yields the first functional organ system of the embryo. In addition to being a fundamental part of embryonic development, vasculogenic processes also have medical importance. To explain the organizational principles behind vascular patterning, we must understand how morphogenesis of tissue level structures can be controlled through cell behavior patterns that, in turn, are determined by biochemical signal transduction processes. Mathematical analyses and computer simulations can help conceptualize how to bridge organizational levels and thus help in evaluating hypotheses regarding the formation of vascular networks. Here we discuss the ideas that have been proposed to explain the formation of the first vascular pattern: cell motility guided by extracellular matrix alignment (contact guidance), chemotaxis guided by paracrine and autocrine morphogens, and sprouting guided by cell-cell contacts. PMID:22692888

  6. Energetics of chondrule formation

    NASA Technical Reports Server (NTRS)

    Levy, E. H.

    1988-01-01

    Meteorite chondrules apparently were formed as a result of localized, transient heating events in the protoplanetary nebula. Such transient events, which seem to have heated the chondrules to temperatures in excess of 1500 C for not more than a few minutes, are not easily explicable in terms of the canonically accepted evolutionary processes of the nebular disk. Thus the occurrence of extraordinary dynamical processes may be indicated by the presence of chondrules and, consequently, the existence of chondrules poses questions fundamental to the understanding of protoplanetary and protostellar systems. This chapter briefly considers the gross energetics, as well as some related questions, of chondrule formation and the implications for several previously proposed sources of chondrule formation energy, including gravitational infall of the nebula, energy derived from solid-body impacts within the nebula, and energy liberated by dissipative evolution of the nebula itself.

  7. Format( )MEDIC( )Input

    NASA Astrophysics Data System (ADS)

    Foster, K.

    1994-09-01

    This document is a description of a computer program called Format( )MEDIC( )Input. The purpose of this program is to allow the user to quickly reformat wind velocity data in the Model Evaluation Database (MEDb) into a reasonable 'first cut' set of MEDIC input files (MEDIC.nml, StnLoc.Met, and Observ.Met). The user is cautioned that these resulting input files must be reviewed for correctness and completeness. This program will not format MEDb data into a Problem Station Library or Problem Metdata File. A description of how the program reformats the data is provided, along with a description of the required and optional user input and a description of the resulting output files. A description of the MEDb is not provided here but can be found in the RAS Division Model Evaluation Database Description document.

  8. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Petruzzo, Charles; Guzman, Jose

    2004-01-01

    This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include (1) targeting to a fixed tetrahedron location and orientation, and (2) rotating and translating the tetrahedron. The number of impulsive maneuvers can also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the NASA Goddard Magnetospheric Multi-Scale (MMS) mission to compute preliminary formation control fuel requirements.

  9. The Star Formation Camera

    Microsoft Academic Search

    Paul A. Scowen; Rolf Jansen; Matthew Beasley; Daniela Calzetti; Steven Desch; Alex Fullerton; John Gallagher; Doug Lisman; Steve Macenka; Sangeeta Malhotra; Mark McCaughrean; Shouleh Nikzad; Robert O'Connell; Sally Oey; Deborah Padgett; James Rhoads; Aki Roberge; Oswald Siegmund; Stuart Shaklan; Nathan Smith; Daniel Stern; Jason Tumlinson; Rogier Windhorst; Robert Woodruff

    2009-01-01

    The Star Formation Camera (SFC) is a wide-field (~15'x19, >280 arcmin^2), high-resolution (18x18 mas pixels) UV\\/optical dichroic camera designed for the Theia 4-m space-borne space telescope concept. SFC will deliver diffraction-limited images at lambda > 300 nm in both a blue (190-517nm) and a red (517-1075nm) channel simultaneously. Our aim is to conduct a comprehensive and systematic study of the

  10. Formation of interpolymer complexes

    Microsoft Academic Search

    Eishun Tsuchida; Yoshihito Osada; Hiroyuki Ohno

    1980-01-01

    Interpolymer complex formations of poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) with oligocations as well as poly(ethylene oxide) (PEO), and poly-(N-vinyl-2-pyrrolidone of various chain lengths were studied. For the case of complexation between PMAA and oligocations, the standard free energy change for the complexation ?G° was found to be linearly dependent on the number of interacting sites, n. The stability

  11. Flocks and Formations

    Microsoft Academic Search

    J. J. P. Veerman; G. Lafferriere; J. S. Caughman; A. Williams

    2005-01-01

    Given a large number (the “flock”) of moving physical objects, we investigate physically reasonable mechanisms of influencing\\u000a their orbits in such a way that they move along a prescribed course and in a prescribed and fixed configuration (or “in formation”).\\u000a Each agent is programmed to see the position and velocity of a certain number of others. This flow of information

  12. Quasars and galaxy formation

    E-print Network

    Andrea Cattaneo

    1999-07-23

    Quasars are widely believed to be powered by accretion onto supermassive black holes and there is now considerable evidence for a link between mergers, quasars and the formation of spheroids. Cattaneo, Haehnelt & Rees (1999) have demonstrated that a very simple model in which supermassive black holes form and accrete most of their mass in mergers of galaxies of comparable masses can reproduce the observed relation of black hole mass to bulge luminosity. Here we show that this simple model can account for the luminosity function of quasars and for the redshift evolution of the quasar population provided a few additional assumptions are made. We use the extended Press-Schechter formalism to simulate the formation of galaxies in hierarchical models of the formation of structures and we assume that, when two galaxies of comparable masses merge, their central black holes coalesce and a fraction of the gas in the merger remnant is accreted by the supermassive black hole over a time-scale of about 10^7 yr. We find that the decrease in the merging rate with cosmic time and the depletion in the amount of cold gas available due to the formation of stars are not sufficient to explain the strong decline in the space density of bright quasars between z=2 and z=0, since larger and larger structures form, which can potentially host brighter and brighter quasars. To explain the redshift evolution of the space density of bright quasars between z=2 and z=0 we need to assume that there is a dependence on redshift either in the fraction of available gas accreted or in the time-scale for accretion.

  13. Hail Formation in Florida

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    Hail poses a substantial threat to life and property in the state of Florida. These losses could be minimized through better understanding of the relationships between atmospheric variables that impact hail formation in Florida. Improving hail forecasting in Florida requires analyzing a number of meteorological parameters and synoptic data related to hail formation. NOAA archive data was retrieved to create a database that was used to categorize text files of hail days. The text files were entered into the National Oceanic and Atmospheric Administration Earth System Research Laboratory website to create National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis maps of atmospheric variables for Florida hail days as well as days leading to the hail event. These data were then analyzed to determine the relationship between variables that affect hail formation, in general, across different regions and seasons in Florida using Statistical Product and Service Solutions. The reasoning for the differing factors affecting hail formation between regions, seasons and hail sizes were discussed, as well as forecasting suggestions relating to region and month in Florida. The study found that the majority of all hail that occurs in Florida is during the wet season. A low Lifted Index, high Precipitable Water and lower than average Sea Level Pressure, in most cases, is present during hail days in Florida. Furthermore, results show that Vector Wind magnitude increases as hail size increases. Additionally, several atmospheric variables useful to studying hail events, such as Lifted Index, Precipitable Water, Sea Level Pressure, Vector Wind and Temperature have significant correlations with each other depending on the region and season being observed. Strong correlations between low Lifted Index, high Precipitable Water values and the occurrence of hail events are discussed, as well as the relationship between temperature anomalies at various pressure levels and the occurrence of hail events.

  14. Drumlin Formation Library Work

    NSDL National Science Digital Library

    Alison M Anders

    Students will individually produce a written introduction for a paper about the presence of drumlins on Mars - this introduction describes different models for drumlin formation on earth. To prepare for this assignment, students work in groups to do library research to find and read articles. The groups summarize their findings for each other. Each student then writes an introduction incorporating material from all the groups. Designed for a geomorphology course Uses geomorphology to solve problems in other fields

  15. Cave Formation: Biogeochemical Cycles

    NSDL National Science Digital Library

    This video explores the role of biogeochemical cycles in the formation of caves. It discusses a radical new theory that identifies sulfuric acid as a cave-forming agent. The video, adapted from a NOVA broadcast, identifies the source of the sulfuric acid, which, unlike carbonic acid, the typical cave-forming agent, does not readily form in nature. The segment is 5 minutes and forty seconds in length.

  16. Anaphylatoxin formation in sepsis.

    PubMed

    Bengtson, A; Heideman, M

    1988-05-01

    Complement activation and anaphylatoxin formation were studied in 27 septic patients. The patients were treated with antibiotics and high-dose corticosteroids. Blood samples were drawn on admission and every week thereafter. Plasma levels of complement components C1INH, C3, C4, and C5 were low before the start of treatment but were above normal one week later in both successfully and unsuccessfully treated patients. In contrast, plasma levels of anaphylatoxins C3a/C3adesArg and C5a/C5adesArg were elevated on admission. After successful treatment, plasma levels of C3a/C3adesArg and C5a/C5adesArg returned to normal within one week. Nine patients had ongoing sepsis one week after the start of treatment and a persistent rise in anaphylatoxin concentration. They developed multisystem organ failure with respiratory, hepatic, and renal insufficiency. In vitro studies of Escherichia coli incubation in fresh serum indicated a dose-related formation of C3a/C3adesArg and C5a/C5adesArg. High concentrations of methylprednisolone inhibited the anaphylatoxin formation in vitro. PMID:3282496

  17. Formation of Lunar Swirls

    E-print Network

    Bamford, R A; Cruz, F; Kellett, B J; Fonseca, R A; Silva, L O; Trines, R M G M; Halekas, J S; Kramer, G; Harnett, E; Cairns, R A; Bingham, R

    2015-01-01

    In this paper we show a plausible mechanism that could lead to the formation of the Dark Lanes in Lunar Swirls, and the electromagnetic shielding of the lunar surface that results in the preservation of the white colour of the lunar regolith. We present the results of a fully self-consistent 2 and 3 dimensional particle-in-cell simulations of mini-magnetospheres that form above the lunar surface and show that they are consistent with the formation of `lunar swirls' such as the archetypal formation Reiner Gamma. The simulations show how the microphysics of the deflection/shielding of plasma operates from a kinetic-scale cavity, and show that this interaction leads to a footprint with sharp features that could be the mechanism behind the generation of `dark lanes'. The physics of mini-magnetospheres is described and shown to be controlled by space-charge fields arising due to the magnetized electrons and unmagnetized ions. A comparison between model and observation is shown for a number of key plasma parameters...

  18. Chemistry of planet formation

    NASA Astrophysics Data System (ADS)

    Robinson, Sarah Elaine

    2008-02-01

    This thesis explores how the chemical environment in which planets develop influences planet formation. The total solid mass, gas/solid ratio, and specific ice inventory of protoplanetary disks can dramatically alter the planet's formation timescale, core/atmosphere mass ratio, and atmosphere composition. We present the results of three projects that probe the links between solar nebula composition and giant planet formation. The first project offers evidence that stars with planets exhibit statistically significant silicon and nickel enrichment over the general metal-rich population. To test whether this prediction is compatible with the core accretion theory of planet formation, we construct new numerical simulations of planet formation by core accretion that establish the timescale on which a planet forming at 5 AU reaches rapid gas accretion, t rga , as a function of solid surface density s solid : ( t rga /1 Myr) = (s solid /25.0 g cm -2 ) - 1.44 . This relation enables us to construct Monte Carlo simulations that predict the fraction of star-disk systems that form planets as a function of [Fe/H], [Si/Fe], disk mass, outer disk radius and disk lifetime. Our simulations reproduce both the known planet-metallicity correlation and the planet-silicon correlation reported in this paper. The simulations predict that 15% of Solar-type stars form Jupiter-mass planets, in agreement with 12% predicted from extrapolation of the observed planet frequency-semimajor axis distribution. Despite the success of our Monte Carlo simulation of the planet-silicon correlation at predicting the properties of extrasolar Jovian planets, there is still no in situ core accretion simulation that can successfully account for the formation of Saturn, Uranus or Neptune within the observed 2-3 Myr lifetimes of protoplanetary disks. Since solid accretion rate is directly proportional to the available planetesimal surface density, one way to speed up planet formation is to take a full inventory of all the solids present in the solar nebula. In Project 2 (Chapter 3) we combine a viscously evolving protostellar disk with a kinetic model of ice formation, which includes not just water but methane, ammonia, CO and 54 minor ices. We use this combined dynamical+chemical simulation to calculate the planetesimal composition and solid surface density in the solar nebula as a function of heliocentric distance and time. We find three effects that strongly favor giant planet formation: (1) a decretion flow that brings mass from the inner solar nebula to the giant planet-forming region, (2) recent lab results (Collings et al. 2004) showing that the ammonia and water ice lines should coincide, and (3) the presence of a substantial amount of methane ice in the trans-Saturnian region. Our results show higher solid surface densities than assumed in the core accretion models of Pollack et al. (1996) by a factor of 3-4 throughout the trans-Saturnian region. We also discuss the location of ice lines and their movement through the solar nebula, and provide new constraints on the possible initial disk configurations from gravitational stability arguments. Finally, we present a core accretion simulation of Saturn with a planet formation timescale of 3.37 Myr, consistent with observed protostellar disk lifetimes. The protostellar disk model underlying this simulation is also capable of forming Jupiter within 2.5 Myr. We observe a new manifestation of the core accretion theory, in which Saturn's solid core does not reach isolation mass, and argue that this paradigm should apply to Uranus and Neptune as well. The planet formation timescale is then governed primarily by the solid accretion rate instead of the gas contraction efficiency. Our model predicts a core mass of 44 M (+) for Saturn, heavier than inferred from observations by a factor of at least 2. We discuss possible mechanisms for reducing the core size without slowing down formation and comment on the similarity between our core- heavy Saturn model and the exoplanet HD 149026 b .

  19. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  20. Terrestrial planet formation

    PubMed Central

    Righter, K.; O’Brien, D. P.

    2011-01-01

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (?106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  1. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Guzman, Jose J.

    2003-01-01

    Spacecraft flying in tetrahedron formations are excellent instrument platforms for electromagnetic and plasma studies. A minimum of four spacecraft - to establish a volume - is required to study some of the key regions of a planetary magnetic field. The usefulness of the measurements recorded is strongly affected by the tetrahedron orbital evolution. This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include targeting to a fixed tetrahedron orientation, rotating and translating the tetrahedron and/or varying the initial and final times. The number of impulsive maneuvers citn also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the Magnetospheric Multiscale Mission (MMS) to compute preliminary formation control fuel requirements.

  2. Massive Star Formation

    E-print Network

    Tan, Jonathan C; Caselli, Paola; Fontani, Francesco; Fuente, Asuncion; Krumholz, Mark R; McKee, Christopher F; Stolte, Andrea

    2014-01-01

    The enormous radiative and mechanical luminosities of massive stars impact a vast range of scales and processes, from the reionization of the universe, to the evolution of galaxies, to the regulation of the interstellar medium, to the formation of star clusters, and even to the formation of planets around stars in such clusters. Two main classes of massive star formation theory are under active study, Core Accretion and Competitive Accretion. In Core Accretion, the initial conditions are self-gravitating, centrally concentrated cores that condense with a range of masses from the surrounding, fragmenting clump environment. They then undergo relatively ordered collapse via a central disk to form a single star or a small-N multiple. In this case, the pre-stellar core mass function has a similar form to the stellar initial mass function. In Competitive Accretion, the material that forms a massive star is drawn more chaotically from a wider region of the clump without passing through a phase of being in a massive,...

  3. Primordial Planet Formation

    NASA Astrophysics Data System (ADS)

    Schild, Rudolph E.; Gibson, Carl H.

    Recent spacecraft observations exploring solar system properties impact standard paradigms of the formation of stars, planets and comets. We stress the unexpected cloud of microscopic dust resulting from the DEEP IMPACT mission, and the existence of molten nodules in STARDUST samples. And the theory of star formation does not explain the common occurrence of binary and multiple star systems in the standard gas fragmentation scenario. No current theory of planet formation can explain the iron core of the earth, under oceans of water. These difficulties are avoided in a scenario where the planet mass objects form primordially and are today the baryonic dark matter. They have been detected in quasar microlensing and anomalous quasar radio brightening bursts. The primordial planets often concentrate together to form a star, with residual matter seen in pre-stellar accretion discs around the youngest stars. These primordial planet mass bodies were formed of hydrogen-helium, aggregated in dense clumps of a trillion at the time of plasma neutralization 380,000 years after the big bang. Most have been frozen and invisible, but are now manifesting themselves in numerous ways as sensitive modern space telescopes become operational. Their key detection signature is their thermal emission spectrum, pegged at the 13.8 degrees Kelvin triple point of hydrogen, the baryonic dark matter (Staplefeldt et al. 1999).

  4. VIRTUAL STRUCTURE BASED SPACECRAFT FORMATION CONTROL WITH FORMATION FEEDBACK

    E-print Network

    Ren, Wei

    VIRTUAL STRUCTURE BASED SPACECRAFT FORMATION CONTROL WITH FORMATION FEEDBACK Wei Ren Randal W. Beard Department of Electrical and Computer Engineering Brigham Young University Provo, UT 84602 fweiren, beardg@ee.byu.edu Abstract Formation control for multiple vehicles has become an active research area

  5. Flexible formation configuration for terrain following flight: Formation keeping constraints

    NASA Astrophysics Data System (ADS)

    Latyshev, Simon

    This work suggests a control method for the terrain-following formation motion of a group of communicating autonomous agents. The presented approach centers on defining a suitable set of constraints for formation keeping task that shall be fulfilled while agents are negotiating an unknown terrain toward the predefined goal location. It allows agents to maintain a general geometric formation shape, while allowing each individual formation member freedom of maneuver, required for terrain collision free motion. Formation structure is defined with the use of virtual leader. Formation keeping constraints are defined with plane surfaces, specified relative to position and navigation vector of the virtual leader. Formation navigation and guidance constraints are defined using navigation vectors of formation members and the virtual leader. Alternative designs for the constraints derived with parabolic, cone, and cylindrical surfaces are considered. Formation control is derived using the Udwadia-Kalaba equation, following corresponding approach to the development of control methods for constraint based dynamical systems, including leader-follower systems defined using geometric constraints. Approach to terrain following motion requiring agents to stay within bounds of cylindrical corridor volumes built around their respective navigation vectors is assumed. Individual formation primitives and multi-level, hierarchical, formation structures are considered. Simulations, based on three degrees of freedom nonlinear model of an agent, performed using Mathematica and specifically developed combined Maya-Mathematica modeling and simulation system, demonstrate that a flexible terrain following formation motion is achieved with the presented sets of constraints.

  6. Star Formation in Irregular Galaxies.

    ERIC Educational Resources Information Center

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  7. Geology of the Little Bluff Creek Area, Mason County, Texas 

    E-print Network

    Mangum, Charles Roland

    1960-01-01

    and schiats respectively. 2. 8. Terr {18/0) concluded Chat the pxesent drainage system in Cho ~no region was superimposed on the ancient Precaxguian and Paleosoic rocks dux ing Tertiary time. Pcige (1/11) named and described Che Cap Mountain... redefined by Paige (1912) who concluded Chat these units vere Algonkian (Proteroaoic) 1n age. Sellarda (l932, p. 33) defined the Packsaddle schist as a thick unit of metamorphosed sediments, ox'lginally con- sisting of ah?les w1th lesser amounts...

  8. Bluff body drag manipulation using pulsed jets and Coanda effect

    E-print Network

    Barros, Diogo; Noack, Bernd R; Spohn, Andreas; Ruiz, Tony

    2015-01-01

    We analyze the effects of unsteady forcing on the wake and drag of a square back blunt body. In combination with a Coanda effect, shear-layer forcing by periodic blowing of wall bounded jets allows to recover over 30 % of the base pressure. The actuation frequency is an order of magnitude higher than the natural shear-layer instabilities. High frequency Coanda blowing leads to a thinner time-averaged wake. The effect of this form shaping is analyzed by pressure taps on the rear side of the model in combination with PIV measurements. Velocity components of the mean field indicate a pressure recovery and favorable mean curvature effects across the separated shear layers in the region close to the rear end of the blunt body when actuation is applied. The wake dynamics further downstream, however, remains very similar to the unforced oscillatory wake mode.

  9. Computing Bluff Body Flows Using Commercial CFD Software

    NASA Astrophysics Data System (ADS)

    Kirpekar, Sujit

    2005-11-01

    Commercial CFD codes are increasingly being used to simulate complex engineering flows. Three commercial codes: CFD-ACE v2004, Fluent 6.2.16 and CFX 5.7.1 are examined for their ability to compute the separated flow over a square cylinder. Large Eddy Simulation (LES) results are presented using four SGS models implemented in these commercial codes: the Smagorinsky's model, the dynamic model (Germano et al., 1991), the localized dynamic model (Kim and Menon, 1995) and the WALE model (Nicoud and Ducros, 1999). Global simulation results, time averaged quantities and phase averaged quantities are benchmarked against the experimental results of Lyn and Rodi (Journal of Fluid Mechanics, 1994). All simulations predict the Strouhal number accurately, and simulations employing the dynamic model are excellent in predicting the mean recirculation length and the r.m.s. of the lift coefficient on the cylinder. In terms of flow fluctuations, all simulations over-predict the streamwise component, but under-predict the vertical component. Velocity fluctuations in the wake correlate well with the fluctuation of forces on the cylinder. An examination of the streamlines of the flow indicates that CFD-ACE and Fluent's implementation of the dynamic model offers the best prediction of the vertical displacement of the wake and the size of the shed vortex. Finally, the addition of 10% upwind differencing to the convective terms is also investigated.

  10. Bluff Your Way in the Second Law of Thermodynamics

    Microsoft Academic Search

    Jos Uffink

    2001-01-01

    The aim of this article is to analyse the relation between the second law of thermodynamics and the so-called arrow of time. For this purpose, a number of different aspects in this arrow of time are distinguished, in particular those of time-reversal (non-)invariance and of (ir)reversibility. Next I review versions of the second law in the work of Carnot, Clausius,

  11. Bluff your way in the second law of thermodynamics

    Microsoft Academic Search

    Jos Uffink

    2000-01-01

    The aim of this article is to analyze the relation between the second law of thermodynamics and the so-called arrow of time. For this purpose, a number of different aspects in this arrow of time are distinguished, in particular those of time-(a)symmetry and of (ir)reversibility. Next I review versions of the second law in the work of Carnot, Clausius, Kelvin,

  12. Large-format holography

    NASA Astrophysics Data System (ADS)

    Ratcliffe, David

    1998-02-01

    A review of the techniques and systems used and developed at Australian Holographics to make large format CW reflection (to 1.1. m X 1.1 m) and rainbow (to 1.1 m X 2.2 m) holograms will be given. Topics such as film holding, optical table design, optical schemes and geometries, the construction of large mirror towers, laser choice and installation, object choice and design, the use of unstable curtains, chemistry, drying and final product mounting will be covered. Pulsed holography as used by Australian Holographics will be briefly mentioned and its relative advantages and disadvantages compared to CW.

  13. Galaxy formation and evolution

    NASA Technical Reports Server (NTRS)

    Cowie, Lennox L.

    1991-01-01

    The presence of high z quasars and radio galaxies tells us that galaxy formation began at z greater than 5, but leaves unanswered the question of when the bulk of galaxies formed. Recent near infrared number counts of galaxies strongly favor a cosmological geometry with q(sub 0) = 0.5 and lambda = 0. Such a model grossly underpredicts blue galaxy counts. Spectroscopy shows that the excess blue galaxies at B = 24 are dwarfs at z approximately equals 0.4 which are no longer seen at the present time. These dwarfs must contain a large amount of baryonic matter which is not included in current estimates of baryonic omega .

  14. Star Cluster Formation and Star Formation: The Role of Environment and Star Formation Efficiencies

    E-print Network

    Uta Fritze

    2008-01-15

    Analyzing global starburst properties in various kinds of starburst and post-starburst galaxies and relating them to the properties of the star cluster populations they form, I explore the conditions for the formation of massive, compact, long-lived star clusters. The aim is to find out whether the relative amount of star formation that goes into star cluster formation as opposed to field star formation, and into the formation of massive long-lived clusters in particular, is universal or scales with star formation rate, burst strength, star formation efficiency, galaxy or gas mass, and whether or not there are special conditions or some threshold for the formation of star clusters that merit to be called globular clusters a few gigayears later.

  15. Urbanization and Slum Formation

    PubMed Central

    Phua, Kai Hong

    2007-01-01

    The formation of slums need not be inevitable with rapid urbanization. Such an argument appears to be contradicted by evidence of large slum populations in a large number of developing countries and particularly in rapidly urbanizing regions like Asia. The evidence discussed suggests that city authorities faced with rapid urban development lack the capacity to cope with the diverse demands for infrastructural provision to meet economic and social needs. Not only are strategic planning and intervention major issues in agenda to manage rapid urbanization, but city governments are not effectively linking the economic development trajectory to implications for urban growth and, hence, housing needs. In the following discussion, a case study is presented in support of the argument that city governments have to first recognize and then act to establish the link that is crucial between economic development, urban growth, and housing. This is the agendum that has been largely neglected by city and national governments that have been narrowly focused on economic growth with the consequent proliferation of slum formation as a housing solution. PMID:17387618

  16. Deep Water Formation

    NASA Technical Reports Server (NTRS)

    Killworth, P. D.

    1984-01-01

    Some simple arguments on plumes of dense water and filling boxes were given. What determines the time for a large-scale environment to be modified by the injection of dense water at its edge is the mass flux, not the buoyancy flux. However, it is the denser buoyancy flux, when there are several competing plumes (e.g., the Mediterranean outflow versus the Denmark Strait outflow) that determines which plume will provide the bottom water for that ocean basin. It was noted that the obvious laboratory experiment (rotate a pie-shaped annulus, and heat/cool it on the surface) had never been performed. Thus, to some extent our belief that deep convection is somehow automatic at high latitudes to close off some ill-defined meridional circulation has never been tested. A summary of deep convection was given. The two fundamental formation mechanisms were shown. Of the two, it is open-ocean convection which forms the water which supplies the Denmark Strait overflow -- in all likelihood, as formation in the Greenland Sea remains stubbornly unobserved. But it is the slope convection which finally creates North Atlantic deep water, following the Denmark Strait overspill.

  17. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1994-01-01

    Two KC-135 flight campaigns have been conducted to date which are specifically dedicated to study bubble formation in microgravity. The first flight was conducted during March 14-18, 1994, and the other during June 20-24, 1994. The results from the June 1994 flight have not been analyzed yet, while the results from the March flight have been partially analyzed. In the first flight three different experiments were performed, one with the specific aim at determining whether or not cavitation can take place during any of the fluid handling procedures adopted in the shuttle bioprocessing experiments. The other experiments were concerned with duplicating some of the procedures that resulted in bubble formation, namely the NCS filling procedure and the needle scratch of a solid surface. The results from this set of experiments suggest that cavitation did not take place during any of the fluid handling procedures. The results clearly indicate that almost all were generated as a result of the breakup of the gas/liquid interface. This was convincingly demonstrated in the scratch tests as well as in the liquid fill tests.

  18. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W. [Naval Research Lab., Washington, DC (United States)

    1996-04-05

    Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than a decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.

  19. CO2 Sequestration Potential of Texas Low-Rank Coals

    SciTech Connect

    Duane A. McVay; Walter B. Ayers, Jr; Jerry L. Jensen

    2006-05-01

    The objectives of this project are to evaluate the feasibility of carbon dioxide (CO{sub 2}) sequestration in Texas low-rank coals and to determine the potential for enhanced coalbed methane (ECBM) recovery as an added benefit of sequestration. The main objectives for this reporting period were to (1) determine the effects of permeability anisotropy on performance of CO{sub 2} sequestration and ECBM production in the Lower Calvert Bluff Formation (LCB) of the Wilcox Group coals in east-central Texas, and (2) begin reservoir and economic analyses of CO{sub 2} sequestration and ECBM production using horizontal wells. To evaluate the effects of permeability anisotropy on CO{sub 2} sequestration and ECBM in LCB coal beds, we conducted deterministic reservoir modeling studies of 100% CO{sub 2} gas injection for the 6,200-ft depth base case (Case 1b) using the most likely values of the reservoir parameters. Simulation results show significant differences in the cumulative volumes of CH{sub 4} produced and CO{sub 2} injected due to permeability anisotropy, depending on the orientation of injection patterns relative to the orientation of permeability anisotropy. This indicates that knowledge of the magnitude and orientation of permeability anisotropy will be an important consideration in the design of CO{sub 2} sequestration and ECBM projects. We continued discussions with Anadarko Petroleum regarding plans for additional coal core acquisition and laboratory work to further characterize Wilcox low-rank coals. As part of the technology transfer for this project, we submitted the paper SPE 100584 for presentation at the 2006 SPE Gas Technology Symposium to be held in Calgary, Alberta, Canada on May 15-18, 2006.

  20. Gas formation. Formation temperatures of thermogenic and biogenic methane.

    PubMed

    Stolper, D A; Lawson, M; Davis, C L; Ferreira, A A; Santos Neto, E V; Ellis, G S; Lewan, M D; Martini, A M; Tang, Y; Schoell, M; Sessions, A L; Eiler, J M

    2014-06-27

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models. PMID:24970083

  1. Petroleum Formation and Occurrence

    NASA Astrophysics Data System (ADS)

    Philp, R. P.

    Organic geochemistry, or to be more specific for the purposes of this review, petroleum geochemistry, is an area of research that has been developing extremely rapidly in the last few years. Many of the concepts developed in research laboratories in the late 1970s are now routinely used by petroleum companies in investigating exploration problems. The second edition of Petroleum Formation and Occurrence reflects many of the changes that have occurred in the field since the first edition of this book was published in 1978. The new chapters that have been added and the parts of the text that have been updated are a clear indication of the areas in which most work has been done in the past 6 years.

  2. Pine Island Iceberg Formation

    NSDL National Science Digital Library

    Lori Perkins

    2002-01-10

    This animation is a sequence showing the formation of the Pine Island iceberg and the glacial seaward flow upstream from the crack. It is a series of MISR images from the Terra satellite on top of the continental Radarsat view of Antarctica. The Pine Island Glacier is the largest discharger of ice in Antarctica and the continents fastest moving glacier. Even so, when a large crack formed across the glacier in mid 2000, it was surprising how fast the crack expanded, 15 meters per day, and how soon the resulting iceberg broke off, mid-November, 2001. This iceberg, called B-21, is 42 kilometers by 17 kilometers and contains seven years of glacier outflow released to the sea in a single event.

  3. Cosmological Structure Formation

    E-print Network

    Primack, Joel R

    2015-01-01

    LCDM is remarkably successful in predicting the cosmic microwave background and large-scale structure, and LCDM parameters have been determined with only mild tensions between different types of observations. Hydrodynamical simulations starting from cosmological initial conditions are increasingly able to capture the complex interactions between dark matter and baryonic matter in galaxy formation. Simulations with relatively low resolution now succeed in describing the overall galaxy population. For example, the EAGLE simulation in volumes up to 100 cubic Mpc reproduces the observed local galaxy mass function nearly as well as semi-analytic models. It once seemed that galaxies are pretty smooth, that they generally grow in size as they evolve, and that they are a combination of disks and spheroids. But recent HST observations combined with high-resolution hydrodynamic simulations are showing that most star-forming galaxies are very clumpy; that galaxies often undergo compaction which reduces their radius and ...

  4. Transitions in biofilm formation

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Thatcher, Travis; Cooley, Benjamin

    2011-03-01

    Biofilms are multicellular, dynamic communities formed by interacting unicellular organisms bound to a surface. Forming a biofilm is a developmental process, characterized by sequential changes in gene expression and behavior as bacteria and yeast progress from discrete, free-swimming cells though stages that arrive at a mature biofilm. We are developing automated metrics to identify key transitions in early biofilm formation as cells attach to a surface, populate that surface, and adhere to each other to form early microcolonies. Our metrics use high-throughput tracking and analysis of microscopy movies to localize these transitions in space and time. Each of these transitions is associated with a loss of entropy in the bacterial system and, therefore, with biological activity that drives this loss of entropy. Better understanding of these transitions will allow automated determination of the strength and turn-on of attractive cell-surface and cell-cell interactions as biofilm development progresses.

  5. Galaxy formation by dust

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Field, Goerge B.

    1989-01-01

    It has been known since the early 1940's that radiation can cause an instability in the interstellar medium. Absorbing dust particles in an isotropic radiation field shadow each other by a solid angle which is inversely proportional to the square of the distance between the two particles, leading to an inverse-square attractive force - mock gravity. The effect is largest in an optically thin medium. Recently Hogan and White (HW, hereafter) proposed that if the pre-galactic universe contained suitable sources of radiation and dust, instability in the dust distribution caused by mock gravity may have led to the formation of galaxies and galaxy clusters. In their picture of a well-coupled dust-gas medium, HW show that mock gravity begins to dominate gravitational instability when the perturbation becomes optically thin, provided that the radiation field at the time is strong enough. The recent rocket observation of the microwave background at submillimeter wavelengths by Matsumoto et al. might be from pre-galactic stars, the consequence of the absorption of ultraviolet radiation by dust, and infrared reemission which is subsequently redshifted. HW's analysis omits radiative drag, incomplete collisional coupling of gas and dust, finite dust albedo, and finite matter pressure. These effects could be important. In a preliminary calculation including them, the authors have confirmed that mock gravitational instability is effective if there is a strong ultraviolet radiation at the time, but any galaxies that form would be substantially enriched in heavy elements because the contraction of the dust is more rapid than that of the gas. Moreover, since the dust moves with supersonic velocity through the gas soon after the perturbation becomes optically thin, the sputtering of dust particles by gas is significant, so the dust could disappear before the instability develops significantly. They conclude that the mock gravity by dust is not important in galaxy formations.

  6. The KEA image file format

    NASA Astrophysics Data System (ADS)

    Bunting, Peter; Gillingham, Sam

    2013-08-01

    There are a large number of image formats already in use within the remote sensing community but currently there is no format that provides the features of: compression, support for large file sizes, ground control points, raster attribute tables and inbuilt image pyramids. Therefore, a new image format, named KEA, after the New Zealand bird, has been proposed. The KEA format provides a full implementation of the GDAL data model and is implemented within a HDF5 file. A software library with a GDAL driver have been freely provided to the community allowing use through any GDAL based software. The new format has comparable performance with existing formats while producing smaller file sizes and is already within active use for a number of projects within Landcare Research, New Zealand, and the wider community.

  7. Gaining Insight into Star Formation: Resolved Star Formation Laws

    NASA Astrophysics Data System (ADS)

    Liebst, Kelley; Scowen, Paul A.

    2014-06-01

    Until recently astronomers have used star formation laws to measure the star formation rate and star formation efficiency of galaxies only on global scales because of the poor resolution of available data. What I am now capable of producing is a spatially resolved star formation law that can provide direct insight into the physical processes that govern star formation and assess the short-term nature of bursts of star formation and the longer-term nature of larger-scale events that can dictate the global distribution of stars and the ultimate fate of a galaxy as a whole. I am using exquisite narrowband optical data from a variety of sources, including the Hubble Space Telescope, and Kitt Peak National Observatory, etc., in conjunction with infrared data from the Spitzer Infrared Nearby Galaxy Survey and the Spitzer Local Volume Legacy survey, neutral gas data from The HI Nearby Galaxy Survey, and molecular gas data from the Berkeley-Illinois-Maryland Association Survey of Nearby Galaxies, to provide star formation rates and star formation efficiencies on previously inaccessible small spatial scales across a suite of galaxies that represent a range of star formation environments and scales. My sample includes 18 spiral galaxies ranging from 2.1 to 15.1 Mpc in distance and offers a large range of morphological types (i.e. a large range of star formation environments). I am using these data to test different models of star formation modes under a variety of physical conditions and relate the variations I observe to the known local physical conditions and the associated star formation histories for each locale within each galaxy.This is the heart of the matter - that the nature and evolution of the local physical environment intimately influences how stars can form, how quickly and how massive those stars are allowed to form, and as a result how they shape the local conditions for subsequent star formation. It is this tracking of the stellar ecology that is vital for insight into the star formation process, but also to understand the conditions that can result in star and planet formation, or conversely what conditions prevent this. Such an analysis is only possible with the kind of datasets I am producing.

  8. Formation and Research in Hydrography Formation et recherche en hydrographie

    E-print Network

    Santerre, Rock

    Formation and Research in Hydrography Formation et recherche en hydrographie ROCK SANTERRE, Ph Programs in Geomatics · Hydrography = Marine Geomatics · Research in Navigation and Hydrography · History of Hydrography Teaching - at Laval University - in New France (Nouvelle-France) R. Santerre, CHC 2010 ­ Québec

  9. Nuclear ``pasta'' formation

    NASA Astrophysics Data System (ADS)

    Schneider, A. S.; Horowitz, C. J.; Hughto, J.; Berry, D. K.

    2013-12-01

    The formation of complex nonuniform phases of nuclear matter, known as nuclear pasta, is studied with molecular dynamics (MD) simulations containing 51200 nucleons. A phenomenological nuclear interaction is used that reproduces the saturation binding energy and density of nuclear matter. Systems are prepared at an initial density of 0.10fm-3 and then the density is decreased by expanding the simulation volume at different rates to densities of 0.01fm-3 or less. An originally uniform system of nuclear matter is observed to form spherical bubbles (“swiss cheese”), hollow tubes, flat plates (“lasagna”), thin rods (“spaghetti”) and, finally, nearly spherical nuclei with decreasing density. We explicitly observe nucleation mechanisms, with decreasing density, for these different pasta phase transitions. Topological quantities known as Minkowski functionals are obtained to characterize the pasta shapes. Different pasta shapes are observed depending on the expansion rate. This indicates nonequilibrium effects. We use this to determine the best ways to obtain lower energy states of the pasta system from MD simulations and to place constraints on the equilibration time of the system.

  10. Bead lightning formation

    SciTech Connect

    Ludwig, G.O.; Saba, M.M.F. [Associated Plasma Laboratory, National Space Research Institute, 12227-010, Sao Jose dos Campos, SP (Brazil); Division of Space Geophysics, National Space Research Institute, 12227-010, Sao Jose dos Campos, SP (Brazil)

    2005-09-15

    Formation of beaded structures in triggered lightning discharges is considered in the framework of both magnetohydrodynamic (MHD) and hydrodynamic instabilities. It is shown that the space periodicity of the structures can be explained in terms of the kink and sausage type instabilities in a cylindrical discharge with anomalous viscosity. In particular, the fast growth rate of the hydrodynamic Rayleigh-Taylor instability, which is driven by the backflow of air into the channel of the decaying return stroke, dominates the initial evolution of perturbations during the decay of the return current. This instability is responsible for a significant enhancement of the anomalous viscosity above the classical level. Eventually, the damping introduced at the current channel edge by the high level of anomalous viscous stresses defines the final length scale of bead lightning. Later, during the continuing current stage of the lightning flash, the MHD pinch instability persists, although with a much smaller growth rate that can be enhanced in a M-component event. The combined effect of these instabilities may explain various aspects of bead lightning.

  11. Formation of "bound

    NASA Astrophysics Data System (ADS)

    Nowak, K.; Kästner, M.; Miltner, A.

    2009-04-01

    During degradation of organic pollutants in soil, metabolites, microbial biomass, CO2and "bound" residues ("non-extractable" residues in soil organic matter) are formed. Enhanced transformation of these contaminants into "bound" residues has been proposed as an alternative remediation method for polluted soils. However, this kind of residues may pose a potential risk for the environment due to their chemical structure and possible remobilization under different conditions. Therefore particular attention is given actually to "bound" residues. Part of these non-extractable residues may be "biogenic," because microorganisms use the carbon from the pollutant to form their biomass components (fatty acids, amino acids, amino sugars), which subsequently may be incorporated into soil organic matter. Furthermore, the CO2 originating from mineralization of xenobiotics, can be re-assimilated by microorganisms and also incorporated into "biogenic residue". The hazard posed by "bound" residues may be overestimated because they are "biogenic" (contain microbial fatty acids and amino acids). The knowledge about the pathways of "biogenic residue" formation is necessary for a proper assessment of the fate of tested pollutants and their turnover in the soil environment. Moreover, these data are needed to establish the realistic degradation rates of the contaminants in soil. The main objectives of this study are: to quantify the extent of "biogenic residue" (fatty acids, amino acids, amino sugars) formation during the degradation of a model pollutant (2,4-dichlorophenoxyacetic acid = 2,4-D) and during CO2 assimilation by microorganisms and to evaluate which components are mainly incorporated into "bound" residues. To investigate the extent of "biogenic residue" formation in soil during the degradation of 2,4-D, experiments with either 14C-U-ring and 13C6-2,4-D or carboxyl-14C 2,4-D were performed. The incubation experiments were performed according to OECD test guideline 307, in the dark, at constant temp 20Ë? C (+/-2Ë? C) and with intermittent aeration. During incubation, the mineralization was quantified and soil samples were analyzed for the presence of both "biogenic residues" and remaining 2,4-D. Mineralization of 2,4-D in both experiments was very high. However, the 14CO2 evolution was higher from carboxyl-14C 2,4-D than from 14C-ring 2,4-D. After 7 days of incubation, 30% of initial amount of 14C in soil contaminated with 14C-ring 2,4-D was mineralized, whereas 40% of total radioactivity was evolved as CO2after 4 days from soil incubated with 14C-carboxyl 2,4-D. The amount of extractable 2,4-D residues was very low in both experiments (14C-ring 2,4-D: 2% and 14C-carboxyl 2,4-D: 1%). The soil incubated with 14C-ring 2,4-D contained 60% of "non-extractable" residues of 2,4-D after 7 days, while the amount of these residues in soil contaminated with 14C-carboxyl 2,4-D reached 50% of the initial radioactivity in the tested system 4 days after application. More "biogenic residues" were formed in soil spiked with 14C-U-ring 2,4-D (10%) than in soil with carboxyl 14C 2,4-D (7%). Both 2,4-D and CO2-derived C were incorporated mainly into microbial amino acids (9.5% at day 7 and 7.0% at day 4, respectively). After 7 days of incubation, 0.5% of initial applied radioactivity in system was found in microbial lipids in the soil contaminated with 14C-ring 2,4-D. Only 0.1% of the total radioactivity was incorporated into lipids in soil treated with 14C-carboxyl 2,4-D on day 4 after application. Thin Layer Chromatography identified the microbial lipids containing the radioactivity as phosphatidylethanolamine, a phospholipid typical for microorganisms. The amount of microbial lipids (which corresponds to phospholipids) in both cases decreased with time; this can be explained by the death of the microbial biomass. To the best of our knowledge, this is the first report on the formation of &qu

  12. Prominence formation and oscillations

    NASA Astrophysics Data System (ADS)

    Chen, P. F.

    Prominences, or filaments, are a striking phenomenon in the solar atmosphere. Besides their own rich features and dynamics, they are related to many other activities, such as solar flares and coronal mass ejections (CMEs). In the past several years we have been investigating the prominence formation, oscillations, and eruptions through both data analysis and radiative hydrodynamic and magnetohydrodynamic (MHD) simulations. This paper reviews our progress on these topics, which includes: (1) With updated radiative cooling function, the coronal condensation becomes a little faster than previous work; (2) Once a seed condensation is formed, it can grow via siphon flow spontaneously even if the evaporation stops; (3) A scaling law was obtained to relate the length of the prominence thread to various parameters, indicating that higher prominences tend to have shorter threads, which is consistent with the fact that threads are long in active region prominences and short in quiescent prominences; (4) It was proposed that long-time prominence oscillations out of phase might serve as a precursor for prominence eruptions and CMEs; (5) An ensemble of oscillating prominence threads may explain the counter-streaming motion.

  13. Formation of caking coals

    SciTech Connect

    Liotta, R.

    1981-03-31

    Highly caking coals are formed by selective oxygen-alkylation or oxygen-acylation of moderately, weakly or non-caking coals, employing a phase transfer reaction which chemically alters phenolic and carboxylic functional substituents. These two very polar functional groups are converted to relatively non-polar ethers and esters, respectively. The o-alkylation or o-acylation is carried out in a binary liquid phase solution (Organic and water phases with a solid phase suspended in the medium). A quaternary ammonium or phosphonium salt is reacted with alkali or alkaline earth base to produce the corresponding quaternary ammonium or phosphonium base (An example of a phase transfer reagent). This quaternary base is non-nucleophilic and readily removes the phenolic and carboxylic protons but does little else to the coal structures. After the removal of the weakly acidic protons by the quaternary base, the phenoxides and carboxylates which are produced then undergo o-alkylation or o-acylation. The alkylating or acylating agent comprises a carbon-bearing functional group and a displaceable leaving group. The process of the invention produces caking properties in noncaking subbituminous coals and increases the caking ability of weakly or moderately caking coals. An important aspect of this invention concerns the coal liquids and gases which are produced during coke formation. The pyrolysis which forms the coke of the o-alkylated or o-acylated coal also produces higher quality coal liquids and gases.

  14. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment. PMID:20069645

  15. THE FORMATION OF PUBLIC OPINION

    Microsoft Academic Search

    Moses A. Boudourides

    Our aim is to review the network concept and its relevance on theories of public opinion formation. For this purpose, after discussing social and policy networks, we are reviewing certain network theories of (i) collective action and (ii) voting choices and preferred modes of political participation. Finally, we are presenting a network simulation of public opinion formation that generalizes Axelrod's

  16. Formative Assessment: A Critical Review

    ERIC Educational Resources Information Center

    Bennett, Randy Elliot

    2011-01-01

    This paper covers six interrelated issues in formative assessment (aka, "assessment for learning"). The issues concern the definition of formative assessment, the claims commonly made for its effectiveness, the limited attention given to domain considerations in its conceptualisation, the under-representation of measurement principles in that…

  17. Organic chemistry of coke formation

    Microsoft Academic Search

    M Guisnet; P Magnoux

    2001-01-01

    The modes of formation of carbonaceous deposits (“coke”) during the transformation of organic compounds over acid and over bifunctional noble metal-acid catalysts are described. At low reaction temperatures, (350°C), the coke components are polyaromatic. Their formation involves hydrogen transfer (acid catalysts) and dehydrogenation (bifunctional catalysts) steps in addition to condensation and rearrangement steps. On microporous catalysts, the retention of coke

  18. Formation stability after hydraulic fracturing

    Microsoft Academic Search

    Panos Papanastasiou

    1999-01-01

    This paper investigates stress changes resulting from fracturing in a weak formation and estimates the reduced risk of formation failure. The analysis is based on fracture propagation and closure of a plane strain elasto-plastic fracture. It is shown that during fracture propagation the area near the fracture tip undergoes plastic deformation, with the result that the in situ stresses there

  19. Formation of the solar system

    Microsoft Academic Search

    C. Hayashi; K. Nakazawa; Y. Nakagawa

    1985-01-01

    The overall evolution of the solar system is discussed in terms of what is called the Kyoto model. Starting from the formation of the solar nebula, a multistep process is followed in detail, including growth and sedimentation of dust grains in the nebula, formation of planetesimals due to fragmentation of a dust layer, radial migration and accumulation of planetesimals to

  20. Professional Development through Formative Evaluation

    ERIC Educational Resources Information Center

    Nsibande, Rejoice; Garraway, James

    2011-01-01

    Formative evaluation and its associated methodology of reflection on practice are used extensively in academic staff development. In reflecting on formative evaluation processes in both more traditional and newer programmes conducted at a university of technology, a number of variables reported in the literature were observed to have influenced…

  1. Distributed Formation Control with Omnidirectional

    Microsoft Academic Search

    Omid Shakernia; Shankar Sastry

    We consider the problem of distributed leader-follower formation control for nonholonomic mobile robots equipped with central-panoramic cameras. By specifying the desired formation in the image plane, we translate the control problem into a separate visual servoing task for each follower. We use a rank constraint on the omni- directional optical ows across multiple frames to estimate the position and velocities

  2. Flowstone Formations in Jewel Cave

    USGS Multimedia Gallery

    Jewel Cave is currently the 3rd most extensive cave network in the world. It is believed to have formed completely underwater, thus leading to the extensive coating of calcite crystals. In the center of the image, a formation known as flowstone can be seen. Flowstone is a type of calcite formation ...

  3. Bibliography Formatting Software: An Update.

    ERIC Educational Resources Information Center

    Stigleman, Sue

    1993-01-01

    Discusses software used for formatting bibliographies and describes 52 programs. Information provided includes type of operating system required, publication formats, citation styles, ability to arrange by subject, use of downloaded references, network versions, costs, and plans for future changes. A directory of the programs and producers is…

  4. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As ...

  5. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As w...

  6. Informatique Nature de la formation

    E-print Network

    Sart, Remi

    Informatique Nature de la formation : Diplôme national de l'Enseignement Supérieur Durée des études formation : Campus des Cézeaux (Aubière) #12;2 Informatique UFR Sciences et Technologies PRÉSENTATION Objectifs L'objectif de la licence Informatique est de donner une connaissance approfondie des systèmes

  7. ASDF: AUDIO SCENE DESCRIPTION FORMAT

    Microsoft Academic Search

    Matthias Geier; Sascha Spors

    The Audio Scene Description Format (ASDF) is an col- laboratively evolving format for the storage and inter- change of static, dynamic and interactive spatial audio content. This position paper briefly describes the current status and raises a list of open questions which shall be addressed in the panel discussion.

  8. Science Sampler: Formative assessment guideposts

    NSDL National Science Digital Library

    Carlos Ayala

    2005-01-01

    A formative assessment can provide a snapshot of what a student knows and is able to do. Use this approach to close the gap between what is known and what needs to be known through informative feedback. Explore the use of formative assessments with navigational help from these six guideposts.

  9. Treating fines containing earthen formations

    Microsoft Academic Search

    D. R. Watkins; L. J. Kalfayan; R. K. Knight; D. C. Young

    1985-01-01

    Method for treating earthen formations which contain water-sensitive, finely divided particulate matter wherein there is injected into the formation steam or a mixture of steam and hot water containing an effective fines-stabilizing amount of a compound containing ammoniacal nitrogen selected from the group consisting of ammonium hydroxide, an ammonium salt of an inorganic acid, an ammonium salt of a carboxylic

  10. FORMATION OF SECONDARY ORGANIC AEROSOL

    EPA Science Inventory

    (1) Gas-phase chemistry. With the clear and profound effect of the VOC/NOx ratio on SOA formation, we will augment gas-phase VOC oxidation mechanisms in atmospheric models to account for the effect of NOx level on the mechanism of SOA formation; (2) Revis...

  11. Formation depths of Fraunhofer lines

    E-print Network

    Gurtovenko, E A

    2015-01-01

    We have summed up our investigations performed in 1970--1993. The main task of this paper is clearly to show processes of formation of spectral lines as well as their distinction by validity and by location. For 503 photospheric lines of various chemical elements in the wavelength range 300--1000 nm we list in Table the average formation depths of the line depression and the line emission for the line centre and on the half-width of the line, the average formation depths of the continuum emission as well as the effective widths of the layer of the line depression formation. Dependence of average depths of line depression formation on excitation potential, equivalent widths, and central line depth are demonstrated by iron lines.

  12. Plasmapause formation at Saturn

    NASA Astrophysics Data System (ADS)

    Thomsen, M. F.; Mitchell, D. G.; Jia, X.; Jackman, C. M.; Hospodarsky, G.; Coates, A. J.

    2015-04-01

    Cassini observations during a rapid, high-latitude, dawnside pass from Saturn's lobe to inner magnetosphere on 25 June 2009 provide strong evidence for the formation of a "plasmapause" at Saturn by Vasyliunas-type nightside reconnection of previously mass-loaded flux tubes. A population of hot, tenuous plasma that lies between the lobe and the dense inner magnetospheric plasma is consistent with a region formed by very recent injection from a reconnection region in the tail, including low density, high temperature, supercorotational flow, a significant O+ content, and the near-simultaneous observation of enhanced Saturn kilometric radiation emissions. The sharp boundary between that region and the cool dense inner magnetospheric plasma thus separates flux tubes that were involved in the reconnection from those that successfully traversed the nightside without mass loss. This event demonstrates that tail reconnection can strip off inner magnetospheric plasma in to at least dipole L = 8.6. Clear evidence of flux tube interchange driven by the sharp boundary is found, both inward moving flux tubes of hotter plasma and, for the first time, the outward moving cool population. The outward moving cool regions have azimuthal sizes less than 1 RS, were probably created within the past 1.2 h, and have outflow speeds greater than about 5 km/s. At the outer edge of the reconnected region, there is also a possible signature of Dungey-type lobe reconnection following the initial Vasyliunas-type reconnection. Observations from this event are entirely consistent with previously described global MHD simulations of tail reconnection, plasmoid departure, and Saturnward injection of reconnected flux.

  13. Light meromyosin paracrystal formation

    PubMed Central

    Chowrashi, PK; Pepe, FA

    1977-01-01

    Studies of paracrystal formation by column purified light meromyosin (LMM) prepared in a variety of ways led to the following conclusions: (a) different portions of the myosin rod may be coded for different stagger relationships. This was concluded from observations that paracrystals with different axial repeat periodicities could be obtained either with LMM framents of different lengths prepared with the same enzyme, or with LMM fragments of identical lengths but prepared with different enzymes. (b) Paracrystals with a 14-nm axial repeat periodicity are most likely formed by the aggregation of sheets with a 44-nm axial repeat within the sheets which are staggered by 14 nm. All of the axial repeat patterns expected from one sheet or aggregates of more than one sheet, on this basis, were observed in the same electron micrograph. (c) C-protein binding probably occurs preferentially to LMM molecules related in some specific way. This was concluded from the observation that the same axial repeat pattern was obtained in paracrystals formed from different LMM preparations in the presence of C-protein, regardless of differences in the axial repeat obtained in the absence of C-protein. (d) Nucleic acid is responsible for the 43-nm axial repeat patterns observed in paracrystals formed by the ethanol-resistant fraction of LMM. In the absence of nuclei acid, paracrystals with a 14nm axial repeat are obtained. (e) The 43-nm axial repeat pattern observed with the ethanol-resistant fraction of LMM is different for LMM preparations obtained by trypsin and papain digestions. PMID:326798

  14. The formation of Pangea

    NASA Astrophysics Data System (ADS)

    Stampfli, G. M.; Hochard, C.; Vérard, C.; Wilhem, C.; vonRaumer, J.

    2013-05-01

    The making of Pangea is the result of large-scale amalgamation of continents and micro-continents, which started at the end of the Neoproterozoic with the formation of Gondwana. As pieces were added to Gondwana on its South-American, Antarctica and Australia side, ribbon-like micro-continents were detached from its African and South-Chinese side: Cadomia in the late Neoproterozoic, Avalonia and Hunia in the Ordovician, Galatia in the Devonian and Cimmeria in the Permian. Cadomia was re-accreted to Gondwana, but the other ribbon-continents were accreted to Baltica, North-China, Laurussia or Laurasia. Finding the origin of these numerous terranes is a major geological challenge. Recently, a global plate tectonic model was developed together with a large geological/geodynamic database, at the Lausanne University, covering the last 600 Ma of the Earth's history. Special attention was given to the placing of Gondwana derived terranes in their original position, using all possible constraints. We propose here a solution for the Variscan terranes, another paper deals with the Altaids. The Galatian super-terrane was detached from Gondwana in the Devonian, during the opening of Paleotethys, and was quickly separated into four sub-terranes that started to by-pass each other. The leading terranes collided at the end of the Devonian with the Hanseatic terrane detached from Laurussia. In the Carboniferous, Gondwana started to impinge onto the amalgamated terranes, creating the Variscan chain and the Pangean super-continent. East of Spain Paleotethys remained opened until the Triassic, subducting northward under Laurasia. Roll-back of the Paleotethyan slab triggered the collapse of most of the European Variscan orogen, which was replaced by series of Permian rifts, some of them becoming oceanized back-arc basins during the Triassic. Major force changes at the Pangean plate limits at the end of the Triassic provoked its break-up, through the opening of the proto-Caribbean, central-Atlantic, Alpine-Tethys oceanic seaways.

  15. Jet Formation and Collimation

    NASA Astrophysics Data System (ADS)

    Sauty, Christophe; Tsinganos, Kanaris; Trussoni, Edoardo

    We briefly review our current understanding for the formation, acceleration and collimation of winds to jets associated with compact astrophysical objects such as AGN and µQuasars.All such outflows may be considered to a first approximation as ideal MHD plasmas escaping from a rotating and magnetized accretion disk with a magnetosphere around a central black hole. A crucial ingredient for a correct modelling of the steady state problem is to place the appropriate boundary conditions, by taking into account how information can propagate through the outflow and ensuring, e.g., that shocks produced via the interaction of the flow with the external medium do not affect the overall structure. As an example underlining the role of setting the correct boundary conditions, we make the analogy of the critical surfaces in the steady and axisymmetric MHD problem with the event horizon and ergosphere of a rotating black hole in relativity.We discuss the acceleration of the outflow, by gas, radiation, or wave pressure gradients and also by magnetic mechanisms, showing the important role played by the disk corona in the vicinity of the black hole. Pressure and magnetic confinement both may also play a role in confining the outflow, although magnetic hoop stress confinement is likely to be a rather dominant process in tightly collimated outflows. The possible asymptotical morphology that jets achieve and the instabilities which are likely to explain the observed structures but do not prevent jets to possess toroidal magnetic fields are also reviewed.Finally, it is proposed that in a space where the two main variables are the energy of the magnetic rotator and the angle between the line of sight and the ejection axis, some observed characteristics of AGN jets can be understood. A criterion for the transition of the morphologies of the outflows from highly collimated jets to uncollimated winds is given. It is based on the analysis of a particular class of exact solutions and may somehow generalize other earlier suggestions, such as the spinning of the black hole, the fueling of the central object, or the effects of the environment.Thus, while the horizontal AGN classification from Type 0 to Types 1 and 2 may well be an orientation effect - i.e. a dependence on the viewing angle between the source axis and the observer as in the standard model - the vertical AGN classification with uncollimated outflows (radio-quiet sources) and collimated outflows (radio-loud sources) depends both on the efficiency of the magnetic rotator and the environment in which the outflows propagate.

  16. Dynamics of Earth orbiting formations

    NASA Technical Reports Server (NTRS)

    Ploen, Scott R.; Scharf, Daniel P.; Hadaegh, Fred Y.; Acikmese, Ahmed B.

    2004-01-01

    In this paper the equations of motion of a formation consisting of n spacecraft in Earth orbit are derived via Lagrange's equations. The equations of motion of the formation are developed with respect to both (1) a bound Keplerian reference orbit, and (2) a specific spacecraft in the formation. The major orbital perturbations acting on a formation in low Earth orbit are also included in the analysis. In contrast to the traditional approach based on the balance of linear momentum, the use of Lagrange's equations leads to a high-level matrix derivation of the formation equations of motion. The matrix form of the nonlinear motion equations is then linearized about a bound Keplerian reference orbit. Next, it is demonstrated that under the assumption of a circular reference orbit, the linearized equations of motion reduce to the well-known Hill-Clohessy-Wiltshire equations. The resulting linear and nonlinear dynamic equations lead to maximal physical insight into the structure of formation dynamics, and are ideally suited for use in the design and validation of formation guidance and control laws.

  17. Dissipative processes in galaxy formation.

    PubMed Central

    Silk, J

    1993-01-01

    A galaxy commences its life in a diffuse gas cloud that evolves into a predominantly stellar aggregation. Considerable dissipation of gravitational binding energy occurs during this transition. I review here the dissipative processes that determine the critical scales of luminous galaxies and the generation of their morphology. The universal scaling relations for spirals and ellipticals are shown to be sensitive to the history of star formation. Semiphenomenological expressions are given for star-formation rates in protogalaxies and in starbursts. Implications are described for elliptical galaxy formation and for the evolution of disk galaxies. PMID:11607396

  18. Dissipative processes in galaxy formation.

    PubMed

    Silk, J

    1993-06-01

    A galaxy commences its life in a diffuse gas cloud that evolves into a predominantly stellar aggregation. Considerable dissipation of gravitational binding energy occurs during this transition. I review here the dissipative processes that determine the critical scales of luminous galaxies and the generation of their morphology. The universal scaling relations for spirals and ellipticals are shown to be sensitive to the history of star formation. Semiphenomenological expressions are given for star-formation rates in protogalaxies and in starbursts. Implications are described for elliptical galaxy formation and for the evolution of disk galaxies. PMID:11607396

  19. Positronium beams: Formation and applications

    SciTech Connect

    Weber, M.; Berko, S.; Brown, B.L.; Canter, K.F.; Lynn, K.G.; Mills, A.P. Jr.; Roellig, L.O.; Tang, S.; Viescas, A.

    1985-01-01

    A beam of positronium, Ps, atoms has been constructed by using the high intensity, low energy, monoenergetic positron beam at the Brookhaven National Laboratory. The process of formation and uses of positronium are discussed in this paper. 3 figs. (LSP)

  20. Sandstone Formations in Capitol Reef

    USGS Multimedia Gallery

    Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  1. Lecture Notes on Pattern Formation

    E-print Network

    Schmeiser, Christian

    the existence of morphogenes as the carriers of structural information. Pattern formation is then described. We have three main options: Either the grid speed s := x/t tends to zero, to infinity, or we keep

  2. Use-driven concept formation

    E-print Network

    Roberts, Jennifer M. (Jennifer Marie)

    2010-01-01

    When faced with a complex task, humans often identify domain-specific concepts that make the task more tractable. In this thesis, I investigate the formation of domain-specific concepts of this sort. I propose a set of ...

  3. Dynamics of interfacial pattern formation

    Microsoft Academic Search

    E. Ben-Jacob; Nigel Goldenfeld; J. S. Langer; G. Schoen

    1983-01-01

    A phenomenological model of dendritic solidification incorporating interfacial kinetics, crystalline anisotropy, and a local approximation for the dynamics of the thermal diffusion field is proposed. The preliminary results are in qualitative agreement with natural dendrite-like pattern formation.

  4. Formation of the Solar System

    NSDL National Science Digital Library

    Joshua Barnes

    This chapter from an online astronomy course briefly describes the formation of the solar system from an accretionary disk. Links to additional resources, a homework assignment, and a quiz are included.

  5. Study of the Morrison Formation

    Microsoft Academic Search

    Charles Craig Mook

    1916-01-01

    Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints

  6. The multifaceted planetesimal formation process

    E-print Network

    Johansen, Anders; Tanaka, Hidekazu; Ormel, Chris; Bizzarro, Martin; Rickman, Hans

    2014-01-01

    Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans-Neptunian objects and comets provide a unique record of the physical conditions in the solar nebula. Debris from planetesimal collisions around other stars signposts that the planetesimal formation process, and hence planet formation, is ubiquitous in the Galaxy. The planetesimal formation stage extends from micrometer-sized dust and ice to bodies which can undergo run-away accretion. The latter ranges in size from 1 km to 1000 km, dependent on the planetesimal eccentricity excited by turbulent gas density fluctuations. Particles face many barriers during this growth, arising mainly from inefficient sticking, fragmentation and radial drift. Two promising growth pathways are mass transfer, where small aggregates transfer u...

  7. Cosmic strings and galaxy formation

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund

    1989-01-01

    The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

  8. Thiol isomerases in thrombus formation

    PubMed Central

    Furie, Bruce; Flaumenhaft, Robert

    2014-01-01

    Protein disulfide isomerase, ERp5 and ERp57, among perhaps other thiol isomerases, are important for the initiation of thrombus formation. Using the laser injury thrombosis model in mice to induce in vivo arterial thrombus formation, it was shown that thrombus formation is associated with PDI secretion by platelets, that inhibition of PDI blocked platelet thrombus formation and fibrin generation, and that endothelial cell activation leads to PDI secretion. Similar results using this and other thrombosis models in mice have demonstrated the importance of ERp5 and ERp57 in the initiation of thrombus formation. The integrins ?IIb?3 and ?V?3 play a key role in this process and interact directly with PDI, ERp5 and ERp57. The mechanism by which thiol isomerases participate in thrombus generation is being evaluated using trapping mutant forms to identify substrates of thiol isomerases that participate in the network pathways linking thiol isomerases, platelet receptor activation and fibrin generation. Protein disulfide isomerase as an antithrombotic target is being explored using isoquercetin and quercetin 3-rutinoside, inhibitors of PDI identified by high throughput screening. Regulation of thiol isomerase expression, analysis of the storage and secretion of thiol isomerases and determination of the electron transfer pathway are key issues to understanding this newly discovered mechanism of regulation of the initiation of thrombus formation. PMID:24677236

  9. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  10. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  11. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  12. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  13. 47 CFR 64.2329 - Format.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...telephone exchange service to a requesting directory publisher in the format the publisher...subscriber list information in the format the directory publisher specifies, the carrier shall...the publisher's request, inform the directory publisher that the requested format...

  14. Gypsum Layer in Spearfish Formation, SD

    USGS Multimedia Gallery

    Spearfish Formation near Spearfish, SD. The Spearfish Formation is a red, silty shale with interbedded red sandstone and siltstone. The formation contains massive gypsum deposits, which is the white layer in the photograph....

  15. Micromachining and Burr Formation for Precision Components

    E-print Network

    Hartnett, Jeffrey; Min, Sangkee; Dornfeld, David

    2006-01-01

    Formation and Minimization through Process Control", Precision Engineering,Formation for Precision Component Jeffrey Hartnett, Sangkee Min, David Dornfeld Laboratory for Manufacturing and Sustainability, Department of Mechanical Engineering

  16. Micromachining and Burr Formation for Precision Components

    E-print Network

    Hartnett, Jeffrey; Min, Sangkee; Dornfeld, David

    2007-01-01

    formation and minimization through process control, Precision Engineering,Engineering University of California at Berkeley Berkeley, California USA 94720-1740 Abstract An understanding of burr formation

  17. Resolving the Formation of Protogalaxies

    E-print Network

    John H. Wise

    2008-04-25

    Cosmic structure originated from minute density perturbations in an almost homogeneous universe. The first stars are believed to be very massive and luminous, providing the first ionizing radiation and heavy elements to the universe and forming 100 million years after the Big Bang. The impact from primordial stellar radiation is far reaching and affects subsequent star and galaxy formation. In this thesis, we present results from adaptive mesh refinement calculations of the formation of the first galaxies. We gradually introduce important physical processes, such as molecular hydrogen cooling and stellar feedback, to base models that only consider atomic hydrogen and helium cooling. In these base models, we find that gas in dark matter halos with masses ~10^8 solar masses centrally collapse before multiple fragmentation occurs in a global disc. We then investigate the importance of molecular hydrogen cooling in early structure formation in the presence of a soft ultraviolet radiation background. We find that molecular hydrogen plays an important role in star formation in halos well below a virial temperature of 10,000 K even in the most extreme assumptions of negative radiative feedback. We also present results from the first radiation hydrodynamics calculations of early dwarf galaxy formation. We develop a novel technique, adaptive ray tracing, to accurately transport radiation from primordial stars. We find primordial stellar feedback alters the landscape of early galaxy formation in that its angular momentum is increased and baryon fractions are decreased. We also describe the metal enrichment of the intergalactic medium and early dwarf galaxies. Finally we explore cosmological reionization by these massive, metal-free stars and its effects on star formation in early galaxies.

  18. Numerical Simulations of Galaxy Formation: Cooling, Heating, Star \\\\ Formation

    NASA Astrophysics Data System (ADS)

    Klypin, A. A.

    Formation of luminous matter in the Universe is a complicated process, which includes many processes and components. It is the vastly different scales involved in the process (from star formation on few parsec scales to galaxy clusters and superclusters on megaparsecs scales) and numerous ill-understood processes, which make the whole field a maze of unsolved, but exciting problems. We present new approximations for numerical treatment of multiphase ISM forming stars. The approximations were tested and calibrated using N-body+fluid numerical simulations. We specifically target issues related with effects of unresolved lumpinesses of the gas.

  19. Formation of Molecular Clouds and Global Conditions for Star Formation

    E-print Network

    Dobbs, Clare L; Ballesteros-Paredes, Javier; Bolatto, Alberto D; Fukui, Yasuo; Heyer, Mark; Mac Low, Mordecai-Mark; Ostriker, Eve C; Vázquez-Semadeni, Enrique

    2013-01-01

    Giant molecular clouds (GMCs) are the primary reservoirs of cold, star-forming molecular gas in the Milky Way and similar galaxies, and thus any understanding of star formation must encompass a model for GMC formation, evolution, and destruction. These models are necessarily constrained by measurements of interstellar molecular and atomic gas, and the emergent, newborn stars. Both observations and theory have undergone great advances in recent years, the latter driven largely by improved numerical simulations, and the former by the advent of large-scale surveys with new telescopes and instruments. This chapter offers a thorough review of the current state of the field.

  20. An XML portable chart format.

    PubMed Central

    Chueh, H. C.; Raila, W. F.; Berkowicz, D. A.; Barnett, G. O.

    1998-01-01

    The clinical chart remains the fundamental record of outpatient clinical care. As this information migrates to electronic form, there is an opportunity to create standard formats for transmitting these charts. This paper describes work toward a Portable Chart Format (PCF) that can represent the relevant aspects of an outpatient chart. The main goal of the format is to provide a packaging medium for outpatient clinical charts in a transfer of care scenario. A secondary goal is to support the aggregation of comparable clinical data for outcomes analysis. The syntax used for PCF is Extended Markup Language (XML), a W3C standard. The structure of the PCF is based on a clinically relevant view of the data. The data definitions and nomenclature used are based primarily on existing clinical standards. PMID:9929315

  1. Biofilm formation by Clostridium difficile

    PubMed Central

    Dapa, Tanja; Unnikrishnan, Meera

    2013-01-01

    Clostridium difficile infection (CDI) is a major healthcare-associated disease worldwide. Recurring infections and increasing antibiotic resistance have complicated treatment of CDI. While C. difficile spores are important for transmission and persistence of CDI, other factors such as gut colonization and formation of bacterial communities in the gut may also contribute to pathogenesis and persistence, but have not been well investigated. Recently, we reported that important clinical C. difficile strains are able to form composite biofilms in vitro. C. difficile biofilm formation is a complex process, modulated by several different factors, including cell surface components and regulators. We also reported that bacteria within biofilms are more resistant to high concentrations of vancomycin, the antibiotic of choice for treatment of CDI. Here we summarize our recent findings and discuss the implications of biofilm formation by this anaerobic gut pathogen in disease pathogenesis and treatment. PMID:23892245

  2. International bilateral water treaty formation

    NASA Astrophysics Data System (ADS)

    Espey, Molly; Towfique, Basman

    2004-05-01

    A logistic model is estimated to determine factors that have influenced the formation of bilateral international water treaties over the last 60 years. Results indicate that the larger a water basin is as a percent of a country's size, the more likely the country is to form a treaty regarding its management. On the other hand, the more control over the water basin any given country has, the less likely it will be involved in a treaty. The results also support aspects of two competing theories about the role of country differences, that in some cases they serve as obstacles to treaty formation yet in other cases they encourage treaty formation to formalize management when informal arrangements are not adequate.

  3. Pattern formation in multiplex networks

    PubMed Central

    Kouvaris, Nikos E.; Hata, Shigefumi; Guilera, Albert Díaz-

    2015-01-01

    The advances in understanding complex networks have generated increasing interest in dynamical processes occurring on them. Pattern formation in activator-inhibitor systems has been studied in networks, revealing differences from the classical continuous media. Here we study pattern formation in a new framework, namely multiplex networks. These are systems where activator and inhibitor species occupy separate nodes in different layers. Species react across layers but diffuse only within their own layer of distinct network topology. This multiplicity generates heterogeneous patterns with significant differences from those observed in single-layer networks. Remarkably, diffusion-induced instability can occur even if the two species have the same mobility rates; condition which can never destabilize single-layer networks. The instability condition is revealed using perturbation theory and expressed by a combination of degrees in the different layers. Our theory demonstrates that the existence of such topology-driven instabilities is generic in multiplex networks, providing a new mechanism of pattern formation. PMID:26042606

  4. Paleoenvironmental and paleoclimatic significance of freshwater bivalves in the Upper Jurassic Morrison Formation, Western Interior, USA

    NASA Astrophysics Data System (ADS)

    Good, Steven C.

    2004-05-01

    Freshwater unionid bivalves are spatially and temporally distributed throughout the Morrison depositional basin, and locally dominate the biomass of many aquatic depositional environments. Two bivalve assemblages are identified. Within-channel assemblages are death assemblages that have been transported and may represent mixed assemblages from multiple communities. These assemblages are predominately disarticulated, in current stable orientations, and composed of higher stream velocity ecophenotypes (medium size, lanceolate form, and very thick shells). The floodplain-pond assemblages are disturbed neighborhood assemblages in the mudstones inhabited during life. The bivalves are predominately articulated, variable in size, and composed of low stream velocity ecophenotypes (large maximum sizes, ovate shell shapes, and thinner shells). The glochidial parasitic larval stage of unionid bivalves provides an effective means of dispersing species throughout drainage basins. These larvae attach to fish and are carried through the fluvial drainage where the larvae detach and establish new bivalve communities. Preliminary paleobiogeographic analyses are drawn at the genus level because of the need to reevaluate bivalve species of the Morrison. Unio spp. and Vetulonaia spp. are widespread throughout the Morrison depositional basin, but Hadrodon spp. are restricted to the eastern portion of the Colorado Plateau during Salt Wash Member deposition, suggesting that Salt Wash drainage was isolated from other contemporaneous regions of the basin. Bivalves from five localities in the Morrison Formation were thin-sectioned for growth band analysis. Growth bands of modern unionid bivalves are produced when the valves are forced to close. Closure can produce annual growth bands in response to seasonal variation, such as temperature-induced hibernation, or precipitation-induced aestivation or turbidity. Pseudoannual growth bands form from non-cyclical events such as predation attacks or isolated storm turbidity. Vetulonaia sp. from the Tidwell Member, Green River, Utah, and from Tidwell-equivalent beds at Como Bluff, Wyoming, exhibits continuous growth with no annual banding, suggesting that seasonality of climate and discharge did not vary appreciable during the year. Hadrodon sp. from the Salt Wash Member in Colorado National Monument, Colorado, exhibits annual banding with subequal light and dark bands indicating seasonal cyclicity. Vetulonaia sp. from the Cleveland-Lloyd locality, Utah, exhibits complex banding that indicates a combination of annual and pseudoannual bands. This suggests seasonal cyclicity and intermittent periods of environmental stress (predation, storm-produced turbidity and/or volcanic ash falls). Specimens of Vetulonaia sp. from Dinosaur National Monument, Utah, are replaced by chert with faint ghosts of bands that are too poorly preserved for environmental interpretations. Preliminary growth band studies suggest a change from a uniform optimum habitat in the Tidwell Member to strongly developed annual growth banding in the Salt Wash Member, suggesting cyclic annual precipitation, and finally to irregular banding produced by a complex interaction of weakly developed annual growth bands and pseudoannual bands in the Brushy Basin Member.

  5. Formation of the first stars.

    PubMed

    Bromm, Volker

    2013-11-01

    Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signalled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the ? cold dark matter (?CDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial star formation, the so-called minihalos, having total masses of ~10(6) M? and collapsing at redshifts z ? 20-30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Foremost among them are predictions for the upcoming James Webb space telescope (JWST), to be launched ~2018, and for 'stellar archaeology', which probes the abundance pattern in the oldest, most-metal poor stars in our cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae. PMID:24168986

  6. Formation of the first stars

    NASA Astrophysics Data System (ADS)

    Bromm, Volker

    2013-11-01

    Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signalled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the ? cold dark matter (?CDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial star formation, the so-called minihalos, having total masses of ˜106 M? and collapsing at redshifts z ? 20-30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Foremost among them are predictions for the upcoming James Webb space telescope (JWST), to be launched ˜2018, and for ‘stellar archaeology’, which probes the abundance pattern in the oldest, most-metal poor stars in our cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae.

  7. Conductive Anodic Filament (CAF) Formation

    NASA Astrophysics Data System (ADS)

    Caputo, Antonio

    Conductive anodic filament (CAF) is a failure mode in printed wiring boards (PWBs) which occurs under high humidity and high voltage gradient conditions. The filament, a copper salt, grows from anode to cathode along the epoxy-glass interface. Ready and Turbini (2000) identified this copper salt as the Cu 2(OH)3Cl, atacamite compound. This work has investigated the influence of polyethylene glycol (PEG) and polyethylene propylene glycol (PEPG) fluxing agents on the chemical nature of CAF. For coupons processed with PEPG flux, with and without chloride, a copper-chloride containing compound was formed in the polymer matrix. This compound was characterized using x-ray photoelectron spectroscopy (XPS) as CuCl and an electrochemical mechanism for the formation of the chloride-containing CAF has been proposed. For PEG flux, with and without chloride, it has been shown that CAF only formed, but no copper containing compound formed in the matrix. It appears for PEG fluxed coupons, a PEG-Cu-Cl complex forms, binds the available Cu and acts as a barrier to the formation of CuCl in the polymer matrix. Meeker and Lu Valle (1995) have previously proposed that CAF failure is best represented by two competing reactions -- the formation of a copper chloride corrosion compound (now identified as Cu2(OH)3Cl) and the formation of innocuous trapped chlorine compounds. Since no evidence of any trapped chloride compounds has been found, we propose that the formation of CAF is best represented by a single non-reversible reaction. For coupons processed with a high bromide-containing flux, bromide containing CAF was created and characterized using transmission electron microscopy (TEM) to be Cu2(OH)3Br. In addition, a copper-containing compound was formed in the polymer matrix and characterized using XPS as CuBr. An electrochemical mechanism for the formation of bromide-containing CAF has been proposed based on the XPS data.

  8. Biofilm formation, cleaning, re-formation on polyamide composite membranes

    Microsoft Academic Search

    Arun Subramani; Eric M. V. Hoek

    2010-01-01

    Bacterial adhesion and biofilm formation were studied in a continuous flow annular biofilm reactor using two commercial polyamide composite membranes — a relatively hydrophilic and smooth nanofiltration (NF) membrane and a relatively hydrophobic and rough reverse osmosis (RO) membrane. Multiple probe-liquid contact angle analyses confirmed that both membrane surfaces had nearly identical chemical properties after exposure to bacteria-free nutrient media

  9. Formation Flying In Highly Elliptical Orbits Initializing the Formation

    NASA Technical Reports Server (NTRS)

    Mailhe, Laurie; Schiff, Conrad; Hughes, Steven

    2000-01-01

    In this paper several methods are examined for initializing formations in which all spacecraft start in a common elliptical orbit subsequent to separation from the launch vehicle. The tetrahedron formation used on missions such as the Magnetospheric Multiscale (MMS), Auroral Multiscale Midex (AMM), and Cluster is used as a test bed Such a formation provides full three degrees-of-freedom in the relative motion about the reference orbit and is germane to several missions. The type of maneuver strategy that can be employed depends on the specific initial conditions of each member of the formation. Single-impulse maneuvers based on a Gaussian variation-of-parameters (VOP) approach, while operationally simple and intuitively-based, work only in a limited sense for a special class of initial conditions. These 'tailored' initial conditions are characterized as having only a few of the Keplerian elements different from the reference orbit. Attempts to achieve more generic initial conditions exceed the capabilities of the single impulse VOP. For these cases, multiple-impulse implementations are always possible but are generally less intuitive than the single-impulse case. The four-impulse VOP formalism discussed by Schaub is examined but smaller delta-V costs are achieved in our test problem by optimizing a Lambert solution.

  10. Functions of coccolith formation1

    Microsoft Academic Search

    C. Steven; Karl M. Wilbur

    Abstract Measurements,of discrimination,in fixation,of stable carbon,isotopes,by two,species,of coccolithophorids support the concept that coccolith formation depends on a supply of HCO,- hut that CO, is the principal substrate of photosynthesis. This in turn suggests that coccolith formation,and,photosynthesis,are linked,through,their complementary,influence,on,the in- ternal equilibrium of dissolved inorganic carbon. Measurements,of osmotic responses and transmcmbranc,potential,differences,of calcified and noncalcified,cells showed,that although coccolithophorids behaved as if they

  11. Core formation by giant impacts

    NASA Technical Reports Server (NTRS)

    Tonks, W. B.; Melosh, H. J.

    1992-01-01

    The present model for the timing and mechanisms of planetary core formation argues that once a planet reaches a certain minimum mass, the large impacts that are typical of late accretion can trigger core formation. This model circumvents the difficulties posed by the large-scale segregation of molten iron into diapirs, and the displacement of the cold, elastic interior of the planet by the iron. The analytical melting model used is based on the Hugoniot equations, the empirical relationship for the decline of particle velocity with distance, and the linear shock-particle velocity relationship.

  12. Pattern formation in the geosciences

    PubMed Central

    Goehring, Lucas

    2013-01-01

    Pattern formation is a natural property of nonlinear and non-equilibrium dynamical systems. Geophysical examples of such systems span practically all observable length scales, from rhythmic banding of chemical species within a single mineral crystal, to the morphology of cusps and spits along hundreds of kilometres of coastlines. This article briefly introduces the general principles of pattern formation and argues how they can be applied to open problems in the Earth sciences. Particular examples are then discussed, which summarize the contents of the rest of this Theme Issue. PMID:24191107

  13. Isocurvature mechanism for structure formation

    NASA Astrophysics Data System (ADS)

    Hu, Wayne

    1999-01-01

    We examine a novel mechanism for structure formation involving initial number density fluctuations between relativistic species, one of which then undergoes a temporary downward variation in its equation of state and generates superhorizon-scale density fluctuations. Isocurvature decaying dark matter (IDDM) models provide concrete examples. This mechanism solves the phenomenological problems of traditional isocurvature models, allowing IDDM models to fit the current cosmic microwave background and large-scale structure data, while still providing novel behavior. We characterize the decaying dark matter and its decay products as a single component of ``generalized dark matter.'' This simplifies calculations in decaying dark matter models and others that utilize this mechanism for structure formation.

  14. A Synopsis of Format-Preserving Encryption

    E-print Network

    Rogaway, Phillip

    A Synopsis of Format-Preserving Encryption Phillip Rogaway Department of Computer Science University of California, Davis, USA March 27, 2010 Abstract Format-preserving encryption (FPE) encrypts a plaintext of some specified format into a ciphertext of the same format--for example, encrypting a social

  15. Star formation in active dwarf galaxies

    Microsoft Academic Search

    C. M. Telesco

    1986-01-01

    Star formation and the ISM in active dwarf galaxies are studied based on data from the IRAS Point Source Catalog. The dwarf galaxies that show evidence of recent energetic star formation are generally also strong far-infrared emitters; thus, active current star formation is associated with a history of energetic star formation. A fraction of the galaxies considered here have a

  16. Towards the Rosetta Stone of planet formation

    Microsoft Academic Search

    G. Maciejewski; R. Neuhäuser; R. Errmann; M. Mugrauer; Ch. Adam; A. Berndt; T. Eisenbeiss; S. Fiedler; Ch. Ginski; M. Hohle; U. Kramm; C. Marka; M. Moualla; T. Pribulla; St. Raetz; T. Roell; T. O. B. Schmidt; M. Seeliger; I. Spaleniak; N. Tetzlaff; L. Trepl

    2011-01-01

    Transiting exoplanets (TEPs) observed just ~10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger

  17. Star formation across galactic environments

    NASA Astrophysics Data System (ADS)

    Young, Jason

    I present here parallel investigations of star formation in typical and extreme galaxies. The typical galaxies are selected to be free of active galactic nuclei (AGN), while the extreme galaxies host quasars (the most luminous class of AGN). These two environments are each insightful in their own way; quasars are among the most violent objects in the universe, literally reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to small galaxies which are forming stars at unsustainably high rates. The current paradigm of galaxy formation and evolution suggests that extreme circumstances are key stepping stones in the assembly of galaxies like our Milky Way. To test this paradigm and fully explore its ramifications, this dual approach is needed. My sample of AGN-free galaxies is drawn from the KPNO International Spectroscopic Survey. This Halpha-selected, volume-limited survey was designed to detect star-forming galaxies without a bias toward continuum luminosity. This type of selection ensures that this sample is not biased toward galaxies that are large or nearby. My work studies the KISS galaxies in the mid- and far-infrared using photometry from the IRAC and MIPS instruments aboard the Spitzer Space Telescope. These infrared bands are particularly interesting for star formation studies because the ultraviolet light from young stars is reprocessed into thermal emission in the far-infrared (24mum MIPS) by dust and into vibrational transitions features in the mid-infrared (8.0mum IRAC) by polycyclic aromatic hydrocarbons (PAHs). The work I present here examines the efficiencies of PAH and thermal dust emission as tracers of star-formation rates over a wide range of galactic stellar masses. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has a highly variable efficiency that does not systematically depend on galactic stellar mass. Complementing this study of normal star-forming galaxies, my study of quasar host galaxies utilizes narrow- and medium-band images of eight Palomar-Green (PG) quasars from the WFPC2 and NICMOS instruments aboard the Hubble Space Telescope. Using images of a point-spread function (PSF) star in the same filters, I subtract the PSF of the quasar from each of the target images. The residual light images clearly show the host galaxies of the respective quasars. The narrow-band images were chosen to be centered on the Hbeta, [O II ], [O III], and Paalpha emission lines, allowing the use of line ratios and luminosities to create extinction and star formation maps. Additionally, I utilize the line-ratio maps to distinguish AGN-powered line emission from star formation powered line emission with line-diagnostic diagrams. I find star formation in each of the eight quasar host galaxies in my study. The bulk star-formation rates are lower than expected, suggesting that quasar host galaxies may be dynamically more advanced than previously believed. Seven of the eight quasar host galaxies in this study have higher-than-typical mass-specific star-formation rates. Additionally, I see evidence of shocked gas, supporting the hypotheses presented in earlier works that suggest that AGN activity quenches star formation in its host galaxy by disrupting its gas reservoir.

  18. Pattern formation outside of equilibrium

    Microsoft Academic Search

    M. C. Cross; P. C. Hohenberg

    1993-01-01

    A comprehensive review of spatiotemporal pattern formation in systems driven away from equilibrium is presented, with emphasis on comparisons between theory and quantitative experiments. Examples include patterns in hydrodynamic systems such as thermal convection in pure fluids and binary mixtures, Taylor-Couette flow, parametric-wave instabilities, as well as patterns in solidification fronts, nonlinear optics, oscillatory chemical reactions and excitable biological media.

  19. Predicting DXAA Formation During Chloramination

    E-print Network

    and Sean Raymond New England Water Treatment Technology Assistance Center (NEWTTAC) University of New Source Metedeconk River Lake Austin Water Type 1. Raw 2. Coagulated 3. Membrane Filtered 4. Biodegraded 5 on DXAA formation as a function of water characteristics and chloramination conditions 3. Develop

  20. Sedimentary pyrite formation: An update

    Microsoft Academic Search

    Robert A. Berner

    1984-01-01

    Sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time. The amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter, dissolved sulfate, and reactive detrital iron minerals. Organic matter appears to be

  1. Solids formation on filtrate neutralization

    Microsoft Academic Search

    1988-01-01

    The Separations Technology Laboratory was requested to study what happens when a filtrate solution, which will be a F B-Line product, is neutralized with sodium hydroxide. The primary concern was the formation of solids that could cause damage in pump seals, resulting in their failure. The results of these experiments indicate that under process conditions, granular, crystalline sodium fluoride will

  2. Multiresolution FOPEN SAR image formation

    Microsoft Academic Search

    Robert C. Dipietro; Ronald L. Fante; Richard P. Perry; Mehrdad Soumekh; Laurens D. Tromp

    1999-01-01

    This paper presents a new technique for FOPEN SAR (foliage penetration synthetic aperture radar) image formation of Ultra Wideband UHF radar data. Planar Subarray Processing (PSAP) has successfully demonstrated the capability of forming multi- resolution images for X and Ka band radar systems under MITRE IR&D and the DARPA IBC program. We have extended the PSAP algorithm to provide the

  3. Reflexive Expectation Formation Timo Ehrig

    E-print Network

    Jost, Jürgen

    , and macroeconomic quantities, agents need not only take into account their belief regarding fundamental values there is a fundamental uncertainty about the market process, like after financial crises? How does the formation entertain higher order beliefs regarding the expectations of other economic agents, which are the basis

  4. Introduction Application Layer Message Formats

    E-print Network

    Soltys, Michael

    Definition (Network Packet) A network packet is a formatted unit of data carried by a computer network Packet Header The header contains overhead information about the data carried by the packet Structure of A Network Packet Payload The payload refers to the actual data that the packet is delivering

  5. Batch calcination studies: melt formation

    Microsoft Academic Search

    Shefcik

    1961-01-01

    It is shown that the formation of a meltable calcine by batch calcination of an acidic waste solution containing primary sodium, iron, and aluminum sulfate and nitrate can be predicted. Calcine melting at temperatures less than 900°C can be correlated with the sodium to metal ion ratio and the sulfate to salt nitrate ratio. The minor constituents present in the

  6. Formation of Clastic Sedimentary Rocks

    NSDL National Science Digital Library

    2010-01-01

    This animation traces the formation of sedimentary rock. It starts at a beach environment where sea water minerals cement sand grains together. The animation concludes with a real microscopic image of sandstone showing both mineral grains and cement. The animation can be paused and rewound to stress important points.

  7. Formation of the Giant Planets

    Microsoft Academic Search

    Hiroshi Mizuno

    1980-01-01

    The structure of a gaseous envelope surrounding a protoplanet has been investigated in connection with the formation of the giant planets. Under the assumptions of spherical symmetry and hydrostatic equilibrium, the structure has been calculated for the regions of Jupiter, Saturn, Uranus and Neptune. Energy transfer in the envelope has been taken into account precisely. When the core mass increases

  8. Signal Formation in Various Detectors

    E-print Network

    Manolis Dris; Theo Alexopoulos

    2014-08-15

    In this write up we present the general theory of the signal formation in various detectors. We follow a pedagogical analysis and presentation such that the results could easily understood and applied by the interested reader to the different detector configurations. We include few applications to gaseous detectors, namely, Monitored Drift Tubes (MDT) and microstrip pattern detector of the micromegas type.

  9. Program Evaluation: A Workable Format

    Microsoft Academic Search

    Thomas Matczynski; Joseph Rogus

    1979-01-01

    Evaluation models are abundant but many are complex, say these authors, who present in this article a format for translating theory into practice in a common sense manner. The material is structured around a series of questions which can be addressed in any situation.

  10. Formative Assessment: A Cybernetic Viewpoint

    ERIC Educational Resources Information Center

    Roos, Bertil; Hamilton, David

    2005-01-01

    This paper considers alternative assessment, feedback and cybernetics. For more than 30 years, debates about the bi-polarity of formative and summative assessment have served as surrogates for discussions about the workings of the mind, the social implications of assessment and, as important, the role of instruction in the advancement of learning.…

  11. Formation of Cosmic Dust Bunnies

    Microsoft Academic Search

    Lorin S. Matthews; Ryan L. Hayes; Michael S. Freed; Truell W. Hyde

    2007-01-01

    Planetary formation is an efficient process now thought to take place on a relatively short astronomical time scale. Recent observations have shown that the dust surrounding a protostar emits more efficiently at longer wavelengths as the protoplanetary disk evolves, suggesting that the dust particles are coagulating into fluffy aggregates, \\

  12. Star Formation in NGC 4631

    Microsoft Academic Search

    A. M. Smith; N. R. Collins; R. Bohlin; M. N. Fanelli; S. G. Neff; R. W. O'Connell; M. S. Roberts; T. P. Stecher; W. H. Waller

    1997-01-01

    The group of galaxies including NGC 4631 provides an outstanding example of a galaxy interaction accompanied by intensive star formation. FUV imagery, recorded by the Ultraviolet Imaging Telescope (UIT), exhibits very bright far- ultraviolet (FUV) emission corresponding to the H II regions cataloged by Crillon and Monet (1969). This data is, in our experience, extraordinary in that NCG 4631 is

  13. Stereotype Formation: Biased by Association

    ERIC Educational Resources Information Center

    Le Pelley, Mike E.; Reimers, Stian J.; Calvini, Guglielmo; Spears, Russell; Beesley, Tom; Murphy, Robin A.

    2010-01-01

    We propose that biases in attitude and stereotype formation might arise as a result of learned differences in the extent to which social groups have previously been predictive of behavioral or physical properties. Experiments 1 and 2 demonstrate that differences in the experienced predictiveness of groups with respect to evaluatively neutral…

  14. Compositional Balancing Before Moon Formation

    Microsoft Academic Search

    G. J. Taylor

    2008-01-01

    A striking feature in the compositions of the Earth and Moon is their identical abundances of oxygen isotopes. Most planetary scientists agree that the Moon formed as the result of a giant impact with the proto-Earth. It explains some important characteristics about the Earth and Moon, such as why the Moon has a small metallic iron core, but planetary formation

  15. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying the data. They can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). ...

  16. Formative Assessment in Primary Science

    ERIC Educational Resources Information Center

    Loughland, Tony; Kilpatrick, Laetitia

    2015-01-01

    This action learning study in a year three classroom explored the implementation of five formative assessment principles to assist students' understandings of the scientific topic of liquids and solids. These principles were employed to give students a greater opportunity to express their understanding of the concepts. The study found that…

  17. Mechanisms of polymeric film formation.

    PubMed

    Felton, Linda A

    2013-12-01

    Polymeric films are applied to solid dosage forms for decorative, protective, and functional purposes. These films are generally applied by a spray atomization process, where the polymer is sprayed onto the solid substrate. The mechanism by which films are formed is dependent on whether the polymer is in the dissolved or dispersed state. For solutions, film formation occurs as the solvent evaporates, since the polymer chains are intimately mixed. Film formation from polymeric dispersions, however, requires the coalescence of individual polymer spheres and interpenetration of the polymer chains. Films prepared from polymeric dispersions exhibit a minimum film forming temperature and processing conditions must exceed this temperature in order to form the film. In addition, these systems generally require post-coating storage in temperature and humidity controlled environments to ensure complete polymer coalescence. Incomplete coalescence can lead to significant changes in drug release over time. This review article highlights the basic science principles involved in film formation from both polymeric solutions and dispersions and the variables that influence these film formation processes. PMID:23305867

  18. A standard audit trail format

    SciTech Connect

    Bishop, M. [Univ. of California, Davis, CA (United States). Dept. of Computer Science

    1995-02-01

    The central role of audit trails, or (more properly) logs, in security monitoring needs little description, for it is too well known for any to doubt it. Auditing, or the analysis of logs, is a central part of security not only in computer system security but also in analyzing financial and other non-technical systems. As part of this process, it is often necessary to reconcile logs from different sources. This speaks of a need for a standard logging format. A standard log format robust enough to meet the needs of heterogeneity, transportability across various network protocols, and flexibility sufficient to meet a variety of needs in very different environments must satisfy two basic properties: extensibility and portability. This report presents the author`s proposed format for a standard log record. In section 3, he shows how and where the translation should be done, and in section 4 he demonstrates how log records from several disparate systems would be put into this format. Section 5 concludes with some observations and suggestions for future work.

  19. Biofilm formation in Streptococcus pneumoniae

    PubMed Central

    Domenech, Mirian; García, Ernesto; Moscoso, Miriam

    2012-01-01

    Summary Biofilm?grown bacteria are refractory to antimicrobial agents and show an increased capacity to evade the host immune system. In recent years, studies have begun on biofilm formation by Streptococcus pneumoniae, an important human pathogen, using a variety of in vitro model systems. The bacterial cells in these biofilms are held together by an extracellular matrix composed of DNA, proteins and, possibly, polysaccharide(s). Although neither the precise nature of these proteins nor the composition of the putative polysaccharide(s) is clear, it is known that choline?binding proteins are required for successful biofilm formation. Further, many genes appear to be involved, although the role of each appears to vary when biofilms are produced in batch or continuous culture. Prophylactic and therapeutic measures need to be developed to fight S.?pneumoniae biofilm formation. However, much care needs to be taken when choosing strains for such studies because different S.?pneumoniae isolates can show remarkable genomic differences. Multispecies and in vivo biofilm models must also be developed to provide a more complete understanding of biofilm formation and maintenance. PMID:21906265

  20. Reverse hydrotropy by complex formation.

    PubMed

    Wojciechowski, Kamil; Gutberlet, Thomas; Raghuwanshi, Vikram Singh; Terry, Ann

    2015-01-14

    Self-aggregation of three di-N-alkylated diaza-18-crown-6 ethers (ACEs) was studied in non-polar solvents. The three ACEs differed by the length of the alkyl chain: n-decyl (ACE-10), n-hexadecyl (ACE-16) and n-tetracosane (ACE-24). From the previously reported interfacial tension isotherms, the formation of reverse micelles was expected above ACE concentrations of ?10(-3) M. However, the water content analysis in conjunction with Dynamic Light Scattering (DLS), Fluorescence Correlation Spectroscopy (FCS) and (1)H NMR Diffusion Ordered Spectroscopy (DOSY) do not provide any clear proof of the existence of aggregates. Only the Small Angle Neutron Scattering (SANS) of concentrated toluene ACE solutions reveals the existence of small reverse micelles (probably ACE dimers forming small cages hosting 1-2 water molecules). On the other hand, spectrophotometric and fluorescence dye dissolution studies using eosin Y, tropaeolin OO and methyl orange suggest that ACEs can dissolve these dyes without requiring the formation of aggregates. This discrepancy was interpreted assuming the dye-ACE complexation as the driving force for dye solubilisation, providing a possible mechanism of reverse hydrotropy ("lipotropy") in non-polar solvents. This example shows that special care should be taken when dye solubilisation is used to probe self-aggregation of an amphiphile in non-polar solvents. The amphiphile-dye complex formation might be responsible for false positive results and the aggregate formation should always be confirmed with other methods. PMID:25415596

  1. Brain gangliosides and memory formation

    Microsoft Academic Search

    Hinrich Rahmann

    1995-01-01

    It is generally accepted that the process of molecular facilitation of neuronal circuits by means of stabilization of synaptic contacts represents the structural basis for memory formation. At the distinct zone of synaptic contact the following basic events occur: alterations of the electrical field strength at the outer surface of synaptic membranes, conformational changes of membrane-bound functional proteins (ion channels,

  2. Cave Formations in Wind Cave

    USGS Multimedia Gallery

    Wind Cave is the first cave national park and currently, the 6th most extensive cave network in the world. It's most famous for its large concentration of a fairly rare cave formation known as boxwork. Boxwork is formed when dissolved calcium carbonate crystallized in cracks in surrounding rock. The...

  3. Tourism motivation and expectation formation

    Microsoft Academic Search

    Juergen Gnoth

    1997-01-01

    This theoretical study introduces a model of tourism motivation and expectation formation. It is based on a discussion and operationalization of both the behaviorist notion of drive reduction and the cognitivist constructs of attitudes and values. While the satisfaction of inner-directed values and motivations depends on classes of objects, outer-directed values target specific objects. In the case of trying to

  4. Sedimentary pyrite formation: An update

    NASA Astrophysics Data System (ADS)

    Berner, Robert A.

    1984-04-01

    Sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time. The amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter, dissolved sulfate, and reactive detrital iron minerals. Organic matter appears to be the major control on pyrite formation in normal (non-euxinic) terrigenous marine sediments where dissolved sulfate and iron minerals are abundant. By contrast, pyrite formation in non-marine, freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic-rich fresh water shales from marine shales. Under marine euxinic conditions sufficient H 2S is produced that the dominant control on pyrite formation is the availability of reactive iron minerals. Calculations, based on a sulfur isotope model, indicate that over Phanerozoic time the worldwide average organic carbon-to-pyrite sulfur ratio of sedimentary rocks has varied considerably. High C/S ratios during Permo-Carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time. Low C/S ratios, compared to today, during the early Paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean. The latter could have been due to lower oceanic oxygen levels and/or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time.

  5. Star Formation in Satellite Galaxies

    E-print Network

    C. M. Gutierrez; M. S. Alonso; J. G. Funes; M. B. Ribeiro

    2006-04-14

    We present narrow-band observations of the H$\\alpha$ emission in a sample of 31 satellite orbiting isolated giant spiral galaxies. The sample studied spans the range $-19formation rates are 0.68 and 3.66 M$_\\sun$ yr$^{-1}$ respectively. Maps of the spatial distribution of ionized gas are presented. The star-forming regions show a rich structure in which frequently discrete complexes are imposed over more diffuse structures. In general, the current star formation rates are smaller that the mean values in the past obtained from the current stellar content; this probably indicates a declining rhythm with time in the generation of new stars. However, the reserve of gas is enough to continue fueling the current levels of star formation activity for at least another Hubble time. Four of the objects (NGC 2718b, NGC 4541e, NGC 5965a$_1$ and NGC 5965a$_2$) with higher current star formation rates show clear signs of interaction with close companions of comparable brightness at projected distances of 25, 20 and 2 kpc respectively. The only two galaxies in our sample that do not show star formation activity are members of these interacting systems, and it is unclear if this is a consequence of intrinsic properties (both are Hubble early types) or if it is related with possible disruption of the external parts due to the interaction. In the case of the pair NGC 2718a-b there are indications of gas transport between both galaxies.

  6. Peripheral Leptin Regulates Bone Formation

    PubMed Central

    Turner, Russell T.; Kalra, Satya P.; Wong, Carmen P.; Philbrick, Kenneth A.; Lindenmaier, Laurence B.; Boghossian, Stephane; Iwaniec, Urszula T.

    2012-01-01

    Substantial evidence does not support the prevailing view that leptin, acting through a hypothalamic relay, decreases bone accrual by inhibiting bone formation. To clarify the mechanisms underlying regulation of bone architecture by leptin, we evaluated bone growth and turnover in wild type (WT) mice, leptin receptor-deficient db/db mice, leptin-deficient ob/ob mice and ob/ob mice treated with leptin. We also performed hypothalamic leptin gene therapy to determine the effect of elevated hypothalamic leptin levels on osteoblasts. Finally, to determine the effects of loss of peripheral leptin signaling on bone formation and energy metabolism, we used bone marrow (BM) from WT or db/db donor mice to reconstitute the hematopoietic and mesenchymal stem cell compartments in lethally irradiated WT recipient mice. Decreases in bone growth, osteoblast-lined bone perimeter and bone formation rate were observed in ob/ob mice and greatly increased in ob/ob mice following subcutaneous administration of leptin. Similarly, hypothalamic leptin gene therapy increased osteoblast-lined bone perimeter in ob/ob mice. In spite of normal osteoclast-lined bone perimeter, db/db mice exhibited a mild but generalized osteopetrotic-like (calcified cartilage encased by bone) skeletal phenotype and greatly reduced serum markers of bone turnover. Tracking studies and histology revealed quantitative replacement of BM cells following BM transplantation. WT mice engrafted with db/db BM did not differ in energy homeostasis from untreated WT mice or WT mice engrafted with WT BM. Bone formation in WT mice engrafted with WT BM did not differ from WT mice, whereas bone formation in WT mice engrafted with db/db cells did not differ from the low rates observed in untreated db/db mice. In summary, our results indicate that leptin, acting primarily through peripheral pathways, increases osteoblast number and activity. PMID:22887758

  7. Inside-out planet formation

    SciTech Connect

    Chatterjee, Sourav [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Tan, Jonathan C., E-mail: s.chatterjee@astro.ufl.edu, E-mail: jt@astro.ufl.edu [Departments of Astronomy and Physics, University of Florida, Gainesville, FL 32611 (United States)

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, ?, profiles similar to the minimum mass solar nebula but boosted in normalization by factors ? 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (?cm-m size) 'pebbles', drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ('dead zone') region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ?1 M {sub ?} planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  8. Leader-formation Navigation Using Dynamic Formation Pattern Yangmin Li and Xin Chen

    E-print Network

    Li, Yangmin

    Leader-formation Navigation Using Dynamic Formation Pattern Yangmin Li and Xin Chen Abstract-- Formation navigation is an interesting topic in robotic community. In this paper, we focus on two aspects of formation navigation, leader-formation keeping and obstacle avoidance. A local control strategy based

  9. Formation of quasiparallel Alfven solitons

    NASA Technical Reports Server (NTRS)

    Hamilton, R. L.; Kennel, C. F.; Mjolhus, E.

    1992-01-01

    The formation of quasi-parallel Alfven solitons is investigated through the inverse scattering transformation (IST) for the derivative nonlinear Schroedinger (DNLS) equation. The DNLS has a rich complement of soliton solutions consisting of a two-parameter soliton family and a one-parameter bright/dark soliton family. In this paper, the physical roles and origins of these soliton families are inferred through an analytic study of the scattering data generated by the IST for a set of initial profiles. The DNLS equation has as limiting forms the nonlinear Schroedinger (NLS), Korteweg-de-Vries (KdV) and modified Korteweg-de-Vries (MKdV) equations. Each of these limits is briefly reviewed in the physical context of quasi-parallel Alfven waves. The existence of these limiting forms serves as a natural framework for discussing the formation of Alfven solitons.

  10. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  11. CEA Studies on Halo Formation

    NASA Astrophysics Data System (ADS)

    Pichoff, N.; Beauvais, P.-Y.; Duperrier, R.; Haouat, G.; Lagniel, J.-M.; Uriot, D.

    2003-12-01

    Beginning with the TRISPAL project, halo formation has been extensively studied at CEA last 10 years. Effect of mismatching, non-linear forces, resonances, longitudinal-transverse coupling, intrabeam scattering, and interaction with the residual gas have been explored. They have been studied theoretically from both analytical models and dedicated simulation codes and, for some of them, experimentally from proton beam profile measurements over a high dynamic range in a 26 periods FODO channel. Our knowledge, strongly improved through collaborations with our worldwide colleagues, has been applied to the design of several linac projects, whose last are SPIRAL2 and RX2. The goal of this presentation is to summarise the contribution of the CEA teams to the understanding of the halo formation.

  12. Engineering biofilm formation and dispersal

    PubMed Central

    Wood, Thomas K.; Hong, Seok Hoon; Ma, Qun

    2011-01-01

    Anywhere water is in the liquid state, bacteria will exist as biofilms, which are complex communities of cells cemented together. Although frequently associated with disease and biofouling, biofilms are also important for engineering applications, such as bioremediation, biocatalysis and microbial fuel cells. Here we review approaches to alter genetic circuits and cell signaling toward controlling biofilm formation, and emphasize utilizing these tools for engineering applications. Based on a better understanding of the genetic basis of biofilm formation, we find that biofilms may be controlled by manipulating extracellular signals and that they may be dispersed using conserved intracellular signals and regulators. Biofilms could also be formed at specific locations where they might be engineered to make chemicals or treat human disease. PMID:21131080

  13. The dynamics of city formation*

    PubMed Central

    Henderson, J. Vernon; Venables, Anthony J.

    2013-01-01

    This paper examines city formation in a country whose urban population is growing steadily over time, with new cities required to accommodate this growth. In contrast to most of the literature there is immobility of housing and urban infrastructure, and investment in these assets is taken on the basis of forward-looking behavior. In the presence of these fixed assets cities form sequentially, without the population swings in existing cities that arise in current models, but with swings in house rents. Equilibrium city size, absent government, may be larger or smaller than is efficient, depending on how urban externalities vary with population. Efficient formation of cities with internalization of externalities involves local government intervention and borrowing to finance development. The paper explores the institutions required for successful local government intervention. PMID:25089087

  14. Molecule Formation on Interstellar Grains

    NASA Astrophysics Data System (ADS)

    Vidali, G.

    2011-05-01

    The first experiments that were expressively designed to be applicable to hydrogen formation reactions in the ISM measured the efficiency of formation of molecular hydrogen on a polycrystalline olivine (Pirronello et al. (1997a)). It soon turned out that more was needed, and research began on the mechanism of reaction, on the in uence of the surface morphology, and on the excitation of the just- ormed molecule. In this review, I summarize what we learned from these and other experiments, and where more work is needed: in the elementary steps of reaction, in the bridging of the laboratory-ISM gap (large ux/large surface - small ux/small grain) using simulations, and in using realistic samples of dust grains. Understanding what experiments can and cannot deliver will help in designing and targeting observations, and vice-versa.

  15. Shock Formation in Lovelock Theories

    E-print Network

    Harvey S. Reall; Norihiro Tanahashi; Benson Way

    2014-09-12

    We argue that Lovelock theories of gravity suffer from shock formation, unlike General Relativity. We consider the propagation of (i) a discontinuity in curvature, and (ii) weak, high frequency, gravitational waves. Such disturbances propagate along characteristic hypersurfaces of a "background" spacetime and their amplitude is governed by a transport equation. In GR the transport equation is linear. In Lovelock theories, it is nonlinear and its solutions can blow up, corresponding to the formation of a shock. We show that this effect is absent in some simple cases e.g. a flat background spacetime, and demonstrate its presence for a plane wave background. We comment on weak cosmic censorship, the evolution of shocks, and the nonlinear stability of Minkowski spacetime, in Lovelock theories.

  16. Hail Formation via Microphysical Recycling.

    NASA Astrophysics Data System (ADS)

    Pflaum, John C.

    1980-01-01

    It is suggested that alternation of low-density riming and wet growth processes play a role in hailstone formation. Such alternation of growth processes, which has been called microphysical recycling, is envisioned to operate in the following manner. During low-density riming growth, hailstones require reduced updraft velocities as compared to hailstones growing via classical high-density ice acquisition. During subsequent wet growth, water soaks into the previously acquired porous rime and on freezing produces hard, dense hailstones compatible with samples collected at the surface. Such a two-stage process lessens the dynamical requirements of hail formation.This article elucidates the microphysical recycling mechanism, cloud conditions necessary to initiate it, evidence that it is operational in the atmosphere, and the possible consequences of its existence with regard to hail suppression.

  17. New Paradigms For Asteroid Formation

    E-print Network

    Johansen, Anders; Cuzzi, Jeffrey N; Morbidelli, Alessandro; Gounelle, Matthieu

    2015-01-01

    Asteroids and meteorites provide key evidence on the formation of planetesimals in the Solar System. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially km-scale planetesimals. However, new models challenge this idea by demonstrating that asteroids of sizes from 100 to 1000 km can form directly from the gravitational collapse of small particles which have organised themselves in dense filaments and clusters in the turbulent gas. Particles concentrate passively between eddies down to the smallest scales of the turbulent gas flow and inside large-scale pressure bumps and vortices. The streaming instability causes particles to take an active role in the concentration, by piling up in dense filaments whose friction on the gas reduces the radial drift compared to that of isolated particles. In this chapter we review new paradigms for asteroid formation and compare critically against the observed properties of asteroids as well as constraints from meteo...

  18. Formation of polar ring galaxies

    E-print Network

    F. Bournaud; F. Combes

    2003-02-04

    Polar ring galaxies are peculiar systems in which a gas rich, nearly polar ring surrounds an early-type or elliptical host galaxy. Two formation scenarios for these objects have been proposed: they are thought to form either in major galaxy mergers or by tidal accretion of the polar material from a gas rich donor galaxy. Both scenarios are studied through N-body simulations including gas dynamics and star formation. Constraints on physical parameters are drawn out, in order to determine which scenario is the most likely to occur. Polar ring galaxies from each scenario are compared with observations and we discuss whether the accretion scenario and the merging scenario account for observational properties of polar ring galaxies. The conclusion of this study is that the accretion scenario is both the most likely and the most supported by observations. Even if the merging scenario is rather robust, most polar ring galaxies are shown to be the result of tidal gas accretion events.

  19. Star formation in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Espinosa, J. M. Rodriguez; Rudy, Richard J.; Jones, Barbara

    1987-01-01

    An analysis of the IRAS data for a sample of classical (optically selected) Seyfert galaxies is presented. The IRAS fluxes at 25 micron, 60 micron, and 100 micron are found to be uncorrelated or only very weakly correlated with the UV/Optical continuum flux and the near and mid IR flux at 3.5 and 10 microns. To investigate the possibility that star formation accounts for the far IR flux, the IRAS measurements for the Seyfert galaxies are compared to IRAS observations of a sample of normal spiral galaxies, and a sample of Starburst galaxies. It is shown that the far IR luminosities and far IR colors of Seyfert galaxies are indistinguishable from those of the Starburst galaxies. Besides, normal galaxies are an order of magnitude less luminous than both the Seyfert and the Starburst galaxies. This indicates that star formation produces the bulk of the far infrared emission in Seyfert galaxies.

  20. Star Cluster Formation and Feedback

    E-print Network

    Krumholz, Mark R; Arce, Hector G; Dale, James E; Gutermuth, Robert; Klein, Richard I; Li, Zhi-Yun; Nakamura, Fumitaka; Zhang, Qizhou

    2014-01-01

    Stars do not generally form in isolation. Instead, they form in clusters, and in these clustered environments newborn stars can have profound effects on one another and on their parent gas clouds. Feedback from clustered stars is almost certainly responsible for a number of otherwise puzzling facts about star formation: that it is an inefficient process that proceeds slowly when averaged over galactic scales; that most stars disperse from their birth sites and dissolve into the galactic field over timescales $\\ll 1$ Gyr; and that newborn stars follow an initial mass function (IMF) with a distinct peak in the range $0.1 - 1$ $M_\\odot$, rather than an IMF dominated by brown dwarfs. In this review we summarize current observational constraints and theoretical models for the complex interplay between clustered star formation and feedback.

  1. Equilibrium cluster formation and gelation

    E-print Network

    Rodrigo Sanchez; Paul Bartlett

    2005-06-22

    We study the formation and growth of equilibrium clusters in a suspension of weakly-charged colloidal particles and small non-adsorbing polymers. The effective potential is characterised by a short-range attraction and a long-range repulsion. The size, shape and local structure of the clusters are studied using three-dimensional particle microscopy. We observe a rapid growth in the mean cluster size and the average number of nearest neighbours approaching the gel boundary.

  2. Union formation in fragile families

    Microsoft Academic Search

    Marcia Carlson; Sara Mclanahan; Paula England

    2004-01-01

    In this article, we use data from a new longitudinal survey—the Fragile Families and Child Wellbeing Study—to examine union\\u000a formation among unmarried parents who have just had a child together. We used multinomial logistic regression to estimate\\u000a the effects of economic, cultural\\/interpersonal, and other factors on whether (relative to having no romantic relationship)\\u000a parents are romantically involved and living apart,

  3. Molecular mechanisms of memory formation

    Microsoft Academic Search

    K. T. Ng; M. E. Gibbs; S. F. Crowe; G. L. Sedman; F. Hua; W. Zhao; B. O'Dowd; N. Rickard; C. L. Gibbs; E. Syková; J. Svoboda; P. Jendelová

    1991-01-01

    Studies with neonate chicks, trained on a passive avoidance task, suggest that at least two shorter-term memory stages precede\\u000a long-term, protein synthesis-dependent memory consolidation. Posttetanic neuronal hyperpolarization arising from two distinct\\u000a mechanisms is postulated to underlie formation of these two early memory stages. Maintenance of the second of these stages\\u000a may involve a prolonged period of hyperpolarization brought about by

  4. Hierarchical Clustering and Galaxy Formation

    E-print Network

    Simon D. M. White

    1996-02-12

    I review the theory of hierarchical clustering, starting with an historical overview and moving on to a discussion of those aspects of dissipationless clustering under gravity which are most relevant to galaxy formation. I conclude with some comments on the additional problems which arise when including all the other physics needed to build a realistic picture for the origin and evolution of the galaxy population.

  5. Pyrazines: occurrence, formation and biodegradation

    Microsoft Academic Search

    Rudolf Müller; Sugima Rappert

    2010-01-01

    Pyrazines are a class of compounds that occur almost ubiquitously in nature. Pyrazines can be synthesised chemically or biologically,\\u000a and are used as flavouring additives. The major formation of pyrazines occurs during heating of food. There is very little\\u000a information available on the degradation of these compounds. In humans and animals, pyrazines are excreted as glucuronates\\u000a or bound to glutathione

  6. Hydrodynamics of catheter biofilm formation

    E-print Network

    Sotolongo-Costa, Oscar; Rodriguez-Perez, Daniel; Martinez-Escobar, Sergio; Fernandez-Barbero, Antonio

    2009-01-01

    A hydrodynamic model is proposed to describe one of the most critical problems in intensive medical care units: the formation of biofilms inside central venous catheters. The incorporation of approximate solutions for the flow-limited diffusion equation leads to the conclusion that biofilms grow on the internal catheter wall due to the counter-stream diffusion of blood through a very thin layer close to the wall. This biological deposition is the first necessary step for the subsequent bacteria colonization.

  7. Predicting struvite formation in digestion

    Microsoft Academic Search

    K. N. Ohlinger; T. M. Young; E. D. Schroeder

    1998-01-01

    The solubility constant for struvite (MgNH4PO4·6H2O) was measured in formation and dissolution equilibrium experiments. The proposed solubility constant (pKSO=13.26) accurately predicted struvite precipitation in sludge handling facilities at the Sacramento Regional Wastewater Treatment Plant, whereas the solubility constant in common use did not. An improved method was developed for predicting struvite precipitation potential in anaerobic digestion and post-digestion processes. Method

  8. Hydrogen sulfide inhibits amyloid formation.

    PubMed

    Rosario-Alomar, Manuel F; Quiñones-Ruiz, Tatiana; Kurouski, Dmitry; Sereda, Valentin; Ferreira, Eduardo B; Jesús-Kim, Lorraine De; Hernández-Rivera, Samuel; Zagorevski, Dmitri V; López-Garriga, Juan; Lednev, Igor K

    2015-01-29

    Amyloid fibrils are large aggregates of misfolded proteins, which are often associated with various neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and vascular dementia. The amount of hydrogen sulfide (H2S) is known to be significantly reduced in the brain tissue of people diagnosed with Alzheimer's disease relative to that of healthy individuals. These findings prompted us to investigate the effects of H2S on the formation of amyloids in vitro using a model fibrillogenic protein hen egg white lysozyme (HEWL). HEWL forms typical ?-sheet rich fibrils during the course of 70 min at low pH and high temperatures. The addition of H2S completely inhibits the formation of ?-sheet and amyloid fibrils, as revealed by deep UV resonance Raman (DUVRR) spectroscopy and ThT fluorescence. Nonresonance Raman spectroscopy shows that disulfide bonds undergo significant rearrangements in the presence of H2S. Raman bands corresponding to disulfide (RSSR) vibrational modes in the 550-500 cm(-1) spectral range decrease in intensity and are accompanied by the appearance of a new 490 cm(-1) band assigned to the trisulfide group (RSSSR) based on the comparison with model compounds. The formation of RSSSR was proven further using a reaction with TCEP reduction agent and LC-MS analysis of the products. Intrinsic tryptophan fluorescence study shows a strong denaturation of HEWL containing trisulfide bonds. The presented evidence indicates that H2S causes the formation of trisulfide bridges, which destabilizes HEWL structure, preventing protein fibrillation. As a result, small spherical aggregates of unordered protein form, which exhibit no cytotoxicity by contrast with HEWL fibrils. PMID:25545790

  9. Germanide phase formation and texture

    Microsoft Academic Search

    S. Gaudet; C. Lavoie; C. Detavernier; P. Desjardins

    2006-01-01

    The aim of the present study was to complete a systematic investigation of metal-germanium reactions to isolate promising candidates for contacting Ge-based microelectronic devices. Based on their low formation temperature, low resistivity, limited film roughness, sufficient morphological stability, and limited sensitivity to oxidation, NiGe and PdGe were found to be the most promising candidates. These materials are, however, subject to

  10. Supernova Feedback in Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Dubois, Y.; Teyssier, R.

    2008-06-01

    The hierarchical model of galaxy formation is known to suffer from the ``over-cooling'' problem: the high efficiency of radiative cooling results in too much baryonic matter in a condensed phase (namely, cold gas or stars) when compared to observations. A solution proposed by many authors (see Springel & Hernquist 2003; Fujita et al. 2004; Rasera & Teyssier 2005) is feedback due to supernova (SN) driven winds or active galactic nuclei. Modeling SN feedback by direct injection of thermal energy usually turns out to be inefficient in galaxy-scale simulations, due to the quasi-instantaneous radiation of the SN energy. To avoid this effect, we have developed a new method to incorporate SN feedback in cosmological simulations: using temporary test particles, we reproduce explicitly a local Sedov blast wave solution in the gas distribution. We have performed several self-consistent runs of isolated Navarro, Frenk, & White (1996, hereafter NFW) halos with radiative cooling, star formation, SN feedback and metal enrichment using the adaptive mesh refinement code RAMSES (Teyssier 2002). We have explored the influence of SN feedback on the formation and the evolution of galaxies with different masses. We have studied the efficiency of the resulting galactic winds, as a function of the mass of the parent halo.

  11. Illusory contour formation survives crowding.

    PubMed

    Lau, Jonathan Siu Fung; Cheung, Sing-Hang

    2012-01-01

    Flanked objects are difficult to identify using peripheral vision due to visual crowding, which limits conscious access to target identity. Nonetheless, certain types of visual information have been shown to survive crowding. Such resilience to crowding provides valuable information about the underlying neural mechanism of crowding. Here we ask whether illusory contour formation survives crowding of the inducers. We manipulated the presence of illusory contours through the (mis)alignment of the four inducers of a Kanizsa square. In the inducer-aligned condition, the observers judged the perceived shape (thin vs. fat) of the illusory Kanizsa square, manipulated by small rotations of the inducers. In the inducer-misaligned condition, three of the four inducers (all except the upper-left) were rotated 90°. The observers judged the orientation of the upper-left inducer. Crowding of the inducers worsened observers' performance significantly only in the inducer-misaligned condition. Our findings suggest that information for illusory contour formation survives crowding of the inducers. Crowding happens at a stage where the low-level featural information is integrated for inducer orientation discrimination, but not at a stage where the same information is used for illusory contour formation. PMID:22693333

  12. Galaxies within hierarchical structure formation

    NASA Astrophysics Data System (ADS)

    Munoz, Joseph Antonio

    2010-12-01

    While the structure of the Universe can typically be studied only by observing the light from luminous galaxies, the distribution of the galaxies themselves is ultimately a product of the formation of the dark matter halos that host them. This thesis explores the relationship between galaxies and the hierarchical growth of the cosmic web. Employing analytic and numerical techniques, we investigate the effects of the structure formation on observations of galaxies and use galaxy observations to constrain the underlying theoretical models. On large scales, the Lagrangian-based excursion-set formalism calculates the statistics of halos in a given survey volume, with any Eulerian evolution away from the Hubble flow described by the spherical collapse model. However, we also rely on high-resolution N-body simulations of dark matter to treat the nonlinear behavior on small-scales. We consider how the clustering of massive halos and the rapid evolution of their abundance with redshift informs the interpretation of high-redshift galaxy surveys with the Hubble Space Telescope. We further calculate the density and dynamics of the Shapley Supercluster from X-ray observations of galaxy clusters, primarily from the ROSAT satellite, and place constraints on reionization and the formation of first stars using Sloan Digital Sky Survey data from relics of the early Universe orbiting the Milky Way.

  13. Theory of Planetary System Formation

    NASA Technical Reports Server (NTRS)

    Cassen, Patrick

    1996-01-01

    Observations and theoretical considerations support the idea that the Solar System formed by the collapse of tenuous interstellar matter to a disk of gas and dust (the primitive solar nebula), from which the Sun and other components separated under the action of dissipative forces and by the coagulation of solid material. Thus, planets are understood to be contemporaneous byproducts of star formation. Because the circumstellar disks of new stars are easier to observe than mature planetary systems, the possibility arises that the nature and variety of planets might be studied from observations of the conditions of their birth. A useful theory of planetary system formation would therefore relate the properties of circumstellar disks both to the initial conditions of star formation and to the consequent properties of planets to those of the disk. Although the broad outlines of such a theory are in place, many aspects are either untested, controversial, or otherwise unresolved; even the degree to which such a comprehensive theory is possible remains unknown.

  14. Bubble migration during hydrate formation

    NASA Astrophysics Data System (ADS)

    Shagapov, V. Sh.; Chiglintseva, A. S.; Rusinov, A. A.

    2015-03-01

    A model of the process of migration of methane bubbles in water under thermobaric conditions of hydrate formation is proposed. The peculiarities of the temperature field evolution, migration rate, and changes in the radius and volume fraction of gas hydrate bubbles are studied. It is shown that, with a constant mass flow of gas from the reservoir bottom, for all parameters of the surfacing gas hydrate disperse system, there is a quasistationary pattern in the form of a "step"-like wave. Depending on the relationship of the initial gas bubble density with the average gas density in the hydrate composition determined by the depth from which bubbles rise to the surface, the final radius of hydrate particles may be larger or smaller than the initial gas bubble radii. It is established that the speed at which gas hydrate inclusions rise to the surface decreases by several times due to an increase in their weight during hydrate formation. The influence of the depth of the water reservoir whose bottom is a gas flow source on the dynamics of hydrate formation is studied.

  15. Gas-Phase Infrared; JCAMP Format

    National Institute of Standards and Technology Data Gateway

    SRD 35 NIST/EPA Gas-Phase Infrared; JCAMP Format (PC database for purchase)   This data collection contains 5,228 infrared spectra in the JCAMP-DX (Joint Committee for Atomic and Molecular Physical Data "Data Exchange") format.

  16. Distributed simulation for formation flying applications

    NASA Technical Reports Server (NTRS)

    Sohl, Garett A.; Udomkesmalee, Santi; Kellogg, Jennifer L.

    2005-01-01

    High fidelity engineering simulation plays a key role in the rapidly developing field of space-based formation flying. This paper describes the design and implementation of the Formation Algorithms and Simulation Testbed (FAST).

  17. SHARAD Observations of the Medusae Fossae Formation

    Microsoft Academic Search

    L. M. Carter; B. A. Campbell; T. R. Watters; R. Seu; R. J. Phillips; D. Biccari; J. W. Holt; C. J. Leuschen; J. J. Plaut; A. Safaeinili; R. Orosei; S. E. Smrekar; G. Picardi; N. E. Putzig; A. F. Egan; F. Bernardini

    2007-01-01

    The SHARAD instrument on Mars Reconnaissance Orbiter can be used to look for layering within the Medusae Fossae Formation. We will show current results, including subsurface interfaces beneath thin deposits on the northern boundary of the formation.

  18. 48 CFR 415.204 - Contract format.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 false Contract format. 415.204 Section...Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION...Information 415.204 Contract format. The Senior...

  19. 48 CFR 415.204 - Contract format.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 false Contract format. 415.204 Section...Regulations System DEPARTMENT OF AGRICULTURE CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION...Information 415.204 Contract format. The Senior...

  20. SAR polar format implementation with MATLAB.

    SciTech Connect

    Martin, Grant D.; Doerry, Armin Walter

    2005-11-01

    Traditional polar format image formation for Synthetic Aperture Radar (SAR) requires a large amount of processing power and memory in order to accomplish in real-time. These requirements can thus eliminate the possible usage of interpreted language environments such as MATLAB. However, with trapezoidal aperture phase history collection and changes to the traditional polar format algorithm, certain optimizations make MATLAB a possible tool for image formation. Thus, this document's purpose is two-fold. The first outlines a change to the existing Polar Format MATLAB implementation utilizing the Chirp Z-Transform that improves performance and memory usage achieving near realtime results for smaller apertures. The second is the addition of two new possible image formation options that perform a more traditional interpolation style image formation. These options allow the continued exploration of possible interpolation methods for image formation and some preliminary results comparing image quality are given.

  1. Dynamics and control of electromagnetic satellite formations

    E-print Network

    Ahsun, Umair, 1972-

    2007-01-01

    Satellite formation flying is an enabling technology for many space missions, especially for space-based telescopes. Usually there is a tight formation-keeping requirement that may need constant expenditure of fuel or at ...

  2. 48 CFR 227.7012 - Contract format.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING REQUIREMENTS PATENTS, DATA, AND COPYRIGHTS Infringement Claims, Licenses, and Assignments 227.7012 Contract format. The format at 252.227-7012...

  3. XML Format for SESAME and LEOS

    SciTech Connect

    Durrenberger, J K; Neely, J R; Sterne, P A

    2009-04-29

    The objective of this document is to describe the XML format used by LLNL and LANL to represent the equation-of-state and related material information in the LEOS and SESAME data libraries. The primary purpose of this document is to describe a specific XML format for representing EOS data that is tailored to the nature of the underlying data and is amenable to conversion to both legacy SESAME and LEOS binary formats. The secondary purpose is to describe an XML format that lends itself to a 'natural' representation in a binary file format of the SESAME, pdb or hdf5 form so that this format and related tools can be used for the rapid and efficient development and implementation of prototype data structures. This document describes the XML format only. A working knowledge of LEOS and SESAME formats is assumed.

  4. Treating nahcolite containing formations and saline zones

    DOEpatents

    Vinegar, Harold J

    2013-06-11

    A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

  5. String Formatting Considered Harmful for Novice Programmers

    ERIC Educational Resources Information Center

    Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the…

  6. Secondary Organic Aerosol Formation: New Insights

    Microsoft Academic Search

    R. M. Kamens; M. Jang; S. Lee; N. Czoschke; S. Leungsakul; D. Hu

    2003-01-01

    A discussion of some of the important issues related to secondary organic aerosol (SOA) formation is presented, and SOA formation is placed in a context of global fine aerosol sources. Outdoor smog chamber experiments are described for the purposes of exploring the effects of different types of background aerosols on SOA formation from the reaction of alpha -pinene with NOx

  7. Interchange Format for Hybrid Systems: Abstract Semantics

    E-print Network

    Carloni, Luca

    Interchange Format for Hybrid Systems: Abstract Semantics Alessandro Pinto1 , Luca P. Carloni3] we advocated the need for an interchange format for hybrid systems that enables the integration interchange format. In doing so, we clearly separate the structure of a hybrid system from the semantics

  8. In situ chemical stimulation of diatomite formations

    SciTech Connect

    Davis, B.W.

    1989-05-09

    A method is described of recovering hydrocarbon from a subsurface diatomite formation comprising the steps of: a. introducing an aqueous surface solution into the diatomite formation, the aqueous surface active solution comprising (i) a diatomite/oil/ water wettability improving agent, and (ii) an oil/water interfacial tension lowering agent; and b. producing oil from the diatomite formation.

  9. Distributed Circular Formation Stabilization for Dynamic Unicycles

    E-print Network

    Maggiore, Manfredi

    of understanding the flocking and swarming behavior. On the Engineering side, interest in formation controlDistributed Circular Formation Stabilization for Dynamic Unicycles Mohamed I. El-Hawwary, Member in a desired direction. The vehicles are required to converge to a formation on the circle, expressed

  10. GXL: Toward a Standard Exchange Format

    Microsoft Academic Search

    Richard C. Holt; Andreas Winter; Andy Schiirr

    2000-01-01

    This paper describes ongoing work toward the devel- opment of a standard software exchange format (SEF), for exchanging information among tools that analyze com- puter programs. A particular exchange format called GXL (Graph Exchange Language) is proposed. GXL can be viewed as a merger of well known formats (e. g. GraX, PRO- GRES, RPA, RSF, and TA) for exchanging typed,

  11. SENSOR CONSIDERATIONS FOR DEEP SPACE FORMATION FLYING

    Microsoft Academic Search

    Greg Holt; E. G. Lightsey

    An investigation was performed to evaluate sensor suitability and perfor- mance for formation flying in a variety of spaceborne environments. This was done as a precursor to the development of strategies for novel uses of satel- lite formations in environments other than Low Earth Orbit. A number of sensors were analyzed for noise characteristics and performance. A formation simulation environment

  12. Research on missile formation control system

    Microsoft Academic Search

    Naigang Cui; Changzhu Wei; Jifeng Guo; Biao Zhao

    2009-01-01

    The control system of missile formation flight is described. In this paper, the missile formation flight controller and BTT intelligence missile outer-loop controller are interested. A combination of proportion and differential control of the position error is used in the designing of the missile formation flight controller to generate the control command for the single missile. The missile outer-loop controller

  13. Formative Assessment: Responding to Your Students

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover

    2009-01-01

    This "how-to" book on formative assessment is filled with practical suggestions for teachers who want to use formative assessment in their classrooms. With practical strategies, tools, and examples for teachers of all subjects and grade levels, this book shows you how to use formative assessment to promote successful student learning. Topics…

  14. Electromagnetic Formation Flight of Satellite Arrays

    E-print Network

    Electromagnetic Formation Flight of Satellite Arrays Daniel W. Kwon and David W. Miller February 2005 SSL # 2-05 #12;#12;Electromagnetic Formation Flight of Satellite Arrays By DANIEL W. KWON S;#12;Electromagnetic Formation Flight of Satellite Arrays by DANIEL W. KWON Submitted to the Department of Aeronautics

  15. Formative Assessment: Guidance for Early Childhood Policymakers

    ERIC Educational Resources Information Center

    Riley-Ayers, Shannon

    2014-01-01

    This policy report provides a guide and framework to early childhood policymakers considering formative assessment. The report defines formative assessment and outlines its process and application in the context of early childhood. The substance of this document is the issues for consideration in the implementation of the formative assessment…

  16. Transfer of Training with Formation Flight Trainer.

    ERIC Educational Resources Information Center

    Reid, Gary B.; Cyrus, Michael L.

    The present research was conducted to determine transfer of practice from a formation simulator to actual aircraft flight for the wing aircraft component of the formation flying task. Evidence in support of positive transfer was obtained by comparing students trained in the formation simulator with students who were essentially untrained and with…

  17. Kinetics of Film Formation by Interfacial Polycondensation

    E-print Network

    Freger, Viatcheslav "Slava"

    Kinetics of Film Formation by Interfacial Polycondensation Viatcheslav Freger* Zuckerberg Institute An approximate analytical model of film formation by interfacial polycondensation is presented. The analysis (insipient film formation, slowdown, and diffusion-limited growth) sets a different pattern of local polymer

  18. Successful Student Writing through Formative Assessment

    ERIC Educational Resources Information Center

    Tuttle, Harry Grover

    2010-01-01

    Use formative assessment to dramatically improve your students' writing. In "Successful Student Writing Through Formative Assessment", educator and international speaker Harry G. Tuttle shows you how to guide middle and high school students through the prewriting, writing, and revision processes using formative assessment techniques that work.…

  19. A new PICL trace file format

    SciTech Connect

    Worley, P.H.

    1992-10-01

    A trace file format is described that will be used in future releases of the Portable Instrumented Communication Library (PICL) and ParaGraph. The new format provides improved support for tracing and profiling PICL communication primitives and user-defined events. The new format is also easily extended and may be useful in other instrumentation packages and performance visualization tools.

  20. Nonlinear formation control of marine craft

    Microsoft Academic Search

    Roger Skjetne; Sonja Moi; Thor I. Fossen

    2002-01-01

    This paper investigates formation control of a fleet of ships. The control objective for each ship is to maintain its position in the formation while a (virtual) Formation Reference Point (FRP) tracks a predefined path. This is obtained by using vectorial backstepping to solve two subproblems; a geometric task, and a dynamic task. The former guarantees that the FRP, and

  1. 77 FR 34093 - License Renewal for Calvert Cliffs Nuclear Power Plant, LLC's

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ...resource areas in its evaluation: land use; transportation; socioeconomics; air quality; water quality and use; geology and soils; ecology...construction or expansion of the existing ISFSI footprint beyond that previously approved by the...

  2. Estuarine stream piracy: Calvert County, U.S. Atlantic coastal plain

    NASA Astrophysics Data System (ADS)

    Vogt, Peter R.

    1991-07-01

    The topography of Maryland's western shore of the Chesapeake Bay shows that five streams now flowing eastward into the bay comprise the pirated (and inverted) headwaters of streams previously flowing westward from a vanished Pliocene upland now occupied by the central Chesapeake. Estuarine shoreline erosion during Pleistocene interglaciations removed the upland, exposing the upper reaches of west-flowing stream valleys. Headward (westward) erosion by east-flowing streams then occurred along existing valleys, facilitated by steep eastward gradients and easily eroded valley-floor sediments. Stream inversion may be more common than previously recognized, since any eroding shoreline causes consumption of seaward-draining watershed and steepening of gradients, thus setting the stage for eventual stream inversion.

  3. The formation of cluster galaxies

    NASA Astrophysics Data System (ADS)

    Mancone, Conor L.

    In this work I sought to understand the formation and evolution of galaxies. Specifically, I studied three key aspects of galaxy formation: star formation, mass assembly, and structural evolution. Past research has shown that the formation of a galaxy is strongly coupled to its local environment (i.e. the local galaxy density). Therefore, I studied the evolution of cluster galaxies because clusters are the highest density environments that exist in the universe. In turn, the observational results found herein form a foundation upon which to test theories of galaxy formation in the densest environments. I used the latest sample of galaxy clusters from the Bootes region to measure the near-infrared luminosity function (NIR LF) of cluster galaxies from 0 < z < 2 and estimate the primary epoch of star formation for massive cluster galaxies. I found that massive cluster galaxies formed the bulk of their stars at zf ˜ 2.5, that they evolved passively at z ? 1.3, and that they deviated from passive evolution at higher redshifts. This latter observation suggested that massive cluster galaxies were actively assembling their final stellar masses at z > 1.3. I used deeper IRAC imaging to study the NIR LF of high redshift cluster galaxies (1 < z < 1.5) with focus on the properties of faint (i.e. low mass) galaxies. I found no evidence for evolution of the LF for low mass cluster galaxies out to the highest redshifts studied, which suggested that the cluster galaxy population was in place at high redshift. Finally, I calculated the evolution of the size-mass relationship (SMR) of cluster galaxies as a function of morphology for the high redshift cluster sample. I found that apparent evolution of the SMR can be partially explained by the progenitor bias, but that there was a missing population of large, massive cluster galaxies. These galaxies were either be accreted by clusters at lower redshifts, or the cluster galaxy population underwent size-evolution to account for their presence at low redshift. I developed two new programs to aid in my research as well as future research in this field. I created EzGal, a program which extracts observables (magnitudes, k-corrections, stellar masses, mass-to-light ratios, etc...) from standard stellar population synthesis (SPS) models. This simplified comparisons of observations to many different model sets, and simplified comparison of different model sets to each other. I used EzGal to quantitatively compare various model sets and estimate SPS model uncertainty, and recovered the well known result that SPS models agree best in the optical for old stellar populations, but disagree substantially for intermediate age stellar populations in the NIR. The latter uncertainty was caused by the presence of thermally pulsating AGB stars, which are poorly understood observationally but contribute substantially to the NIR light of a stellar population. I also created the Python Galaxy Fitter (PyGFit), a program which measures PSF matched photometry from crowded imaging with disparate PSFs and resolutions. This enabled accurate measurement of spectral energy distributions (SEDs) in crowded cluster fields.

  4. Testing Magnetic Star Formation Theory

    E-print Network

    Richard M. Crutcher; Nicholas Hakobian; Thomas H. Troland

    2008-10-17

    We report here observations of the Zeeman effect in the 18-cm lines of OH in the envelope regions surrounding four molecular cloud cores toward which detections of B(LOS) have been achieved in the same lines, and evaluate the ratio of mass to magnetic flux, M/Phi, between the cloud core and envelope. This relative M/Phi measurement reduces uncertainties in previous studies, such as the angle between B and the line of sight and the value of [OH/H]. Our result is that for all four clouds, the ratios R of the core to the envelope values of M/Phi are less than 1. Stated another way, the ratios R' of the core to the total cloud M/Phi are less than 1. The extreme case or idealized (no turbulence) ambipolar diffusion theory of core formation requires the ratio of the central to total M/Phi to be approximately equal to the inverse of the original subcritical M/Phi, or R' > 1. The probability that all four of our clouds have R' > 1 is 3 x 10^{-7}; our results are therefore significantly in contradiction with the hypothesis that these four cores were formed by ambipolar diffuson. Highly super-Alfvenic turbulent simulations yield a wide range of relative M/Phi, but favor a ratio R < 1, as we observe. Our experiment is limited to four clouds, and we can only directly test the predictions of the extreme-case "idealized" models of ambipolar-diffusion driven star formation that have a regular magnetic field morphology. Nonetheless, our experimental results are not consistent with the "idealized" strong field, ambipolar diffusion theory of star formation.

  5. Transcriptional regulation in wood formation.

    PubMed

    Demura, Taku; Fukuda, Hiroo

    2007-02-01

    Wood (i.e. xylem tissue) in trees is mainly composed of two types of cells, fibres and tracheary elements. Recent molecular studies of various trees, as well as the non-tree species Arabidopsis thaliana and Zinnia elegans, have revealed coordinated gene expression during differentiation of these cells in wood and the presence of several transcription factors that might govern the complex networks of transcriptional regulation. This article reviews recent findings concerning the regulation of genes by transcription factors involved in wood formation such as AUXIN RESPONSE FACTOR (ARF), CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIPIII), KANADI (KAN), MYB and NAM/ATAF/CUC (NAC). PMID:17224301

  6. Petrophysical evaluation of subterranean formations

    DOEpatents

    Klein, James D; Schoderbek, David A; Mailloux, Jason M

    2013-05-28

    Methods and systems are provided for evaluating petrophysical properties of subterranean formations and comprehensively evaluating hydrate presence through a combination of computer-implemented log modeling and analysis. Certain embodiments include the steps of running a number of logging tools in a wellbore to obtain a variety of wellbore data and logs, and evaluating and modeling the log data to ascertain various petrophysical properties. Examples of suitable logging techniques that may be used in combination with the present invention include, but are not limited to, sonic logs, electrical resistivity logs, gamma ray logs, neutron porosity logs, density logs, NRM logs, or any combination or subset thereof.

  7. Dark Matter and Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Primack, Joel R.

    2009-12-01

    The four lectures that I gave in the XIII Ciclo de Cursos Especiais at the National Observatory of Brazil in Rio in October 2008 were (1) a brief history of dark matter and structure formation in a ?CDM universe; (2) challenges to ?CDM on small scales: satellites, cusps, and disks; (3) data on galaxy evolution and clustering compared with simulations; and (4) semi-analytic models. These lectures, themselves summaries of much work by many people, are summarized here briefly. The slides [1] contain much more information.

  8. Formation of Po@ C60

    NASA Astrophysics Data System (ADS)

    Ohtsuki, T.; Ohno, K.

    2005-10-01

    Radioactive endohedral fullerenes, Po210@C60 and the dimers, are detected by using radiochemical and radiochromatographic techniques. The results show that a Po atom can be inserted into C60 by a recoil process following a nuclear reaction. Using ab initio molecular dynamics simulations based on the all-electron mixed-basis approach, we also theoretically showed that the formation of a Po doped fullerene is possible. These findings may be useful for several nuclear applications such as nuclear medicine and/or nuclear waste disposal.

  9. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, Anthony F. (Berkeley, CA)

    1999-01-01

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area.

  10. Formation Flying and Deformable Instruments

    SciTech Connect

    Rio, Yvon [CEA/IRFU/Sap, CEA Saclay, 91191 Gif sur Yvette (France)

    2009-05-11

    Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

  11. Zonal flow as pattern formation

    SciTech Connect

    Parker, Jeffrey B.; Krommes, John A. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2013-10-15

    Zonal flows are well known to arise spontaneously out of turbulence. We show that for statistically averaged equations of the stochastically forced generalized Hasegawa-Mima model, steady-state zonal flows, and inhomogeneous turbulence fit into the framework of pattern formation. There are many implications. First, the wavelength of the zonal flows is not unique. Indeed, in an idealized, infinite system, any wavelength within a certain continuous band corresponds to a solution. Second, of these wavelengths, only those within a smaller subband are linearly stable. Unstable wavelengths must evolve to reach a stable wavelength; this process manifests as merging jets.

  12. Multi-Robot Formations based on the Queue-Formation Scheme with Limited Communications

    E-print Network

    Ge, Shuzhi Sam

    Multi-Robot Formations based on the Queue-Formation Scheme with Limited Communications Cheng, IEEE Abstract-- In this paper, we investigate the operation of the Queue-formation structure (or Q into formation. It provides greater control over the distance between robots on the same queue for better

  13. Autonomous Formation Flight: Project Overview

    NASA Technical Reports Server (NTRS)

    Cole, Jennifer; Cobleigh, Brent; Vachon, Jake; Ray, Ronald J.; Ennix, Kimberly; Walsh, Kevin

    2008-01-01

    Objectives: a) Map the vortex effects; b) Formation Auto-Pilot Requirements. Two NASA F/A-18 aircraft in formation: a) NASA 845 Systems Research Aircraft; b) NASA 847 Support Aircraft. Flight Conditions: M = 0.56, 25000 feet (Subsonic condition); b) M = 0.86, 36000 feet (Transonic condition). Nose-To-Tail (N2T) Distances: 20, 55, 110 and 190 feet. Lessons learned: a) Controllable flight in vortex is possible with pilot feedback (displays); b) Position hold at best C(sub D), is attainable; c) Best drag location is close to max rolling moment; e) Drag reductions demonstrated up to 22% (WFE up to 20%); f) Induced drag results compare favorably with simple prediction model; g) "Sweet Spot" (lateral & vertical area > 25%) is larger than predicted; h) Larger wing overlaps result in sign reversals in roll, yaw; i) As predicted, favorable effects degrade gradually with increased nose-to-tail distances after peaking at 3 span lengths aft; and j) Demonstrated - over 100 N mi (>15%) range improvement and 650 lbs (14%) fuel savings on actual simulated F/A-18 cruise mission.

  14. Abundance gradients and galaxy formation

    NASA Astrophysics Data System (ADS)

    Stiavelli, M.; Matteucci, F.

    1991-08-01

    A three-dimensional collisionless code is used to simulate the formation of elliptical galaxies with a time scale for star formation comparable to the collapse time. A one-zone chemical evolution scheme is used to compute the evolution of the abundances of several chemical elements. The initial 'clumpy' system is made of gas and, in some cases, of warm dark matter. In the latter case, it is shown that abundance gradients are produced. For a galaxy of 10 to the 11th solar mass of gas and 3 x 10 to the 11th solar mass of warm dark matter, the predicted gradients of Fe and Mg are d(Fe/H)/d log r = -0.11 and d(Mg/H)/d log r = -0.05, respectively. In the absence of dark matter a greater amount of dissipation is required to produce abundance gradients. The mechanism proposed here should be relevant for bright and extended objects where there is evidence for the presence of dark matter.

  15. Computer simulation of bubble formation.

    SciTech Connect

    Insepov, Z.; Bazhirov, T.; Norman, G.; Stegailov, V.; Mathematics and Computer Science; Institute for High Energy Densities of Joint Institute for High Temperatures of RAS

    2007-01-01

    Properties of liquid metals (Li, Pb, Na) containing nanoscale cavities were studied by atomistic Molecular Dynamics (MD). Two atomistic models of cavity simulation were developed that cover a wide area in the phase diagram with negative pressure. In the first model, the thermodynamics of cavity formation, stability and the dynamics of cavity evolution in bulk liquid metals have been studied. Radial densities, pressures, surface tensions, and work functions of nano-scale cavities of various radii were calculated for liquid Li, Na, and Pb at various temperatures and densities, and at small negative pressures near the liquid-gas spinodal, and the work functions for cavity formation in liquid Li were calculated and compared with the available experimental data. The cavitation rate can further be obtained by using the classical nucleation theory (CNT). The second model is based on the stability study and on the kinetics of cavitation of the stretched liquid metals. A MD method was used to simulate cavitation in a metastable Pb and Li melts and determine the stability limits. States at temperatures below critical (T < 0.5Tc) and large negative pressures were considered. The kinetic boundary of liquid phase stability was shown to be different from the spinodal. The kinetics and dynamics of cavitation were studied. The pressure dependences of cavitation frequencies were obtained for several temperatures. The results of MD calculations were compared with estimates based on classical nucleation theory.

  16. Tube Formation in Nanoscale Materials

    PubMed Central

    2008-01-01

    The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gas–solid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquid–solid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities. PMID:20592945

  17. Beaver assisted river valley formation

    USGS Publications Warehouse

    Westbrook, C.J.; Cooper, D.J.; Baker, B.W.

    2011-01-01

    We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. ?? 2010 John Wiley & Sons, Ltd.

  18. Globular Cluster Formation in Mergers

    E-print Network

    Francois Schweizer

    2006-06-01

    Mergers of gas-rich galaxies lead to gravitationally driven increases in gas pressure that can trigger intense bursts of star and cluster formation. Although star formation itself is clustered, most newborn stellar aggregates are unbound associations and disperse. Gravitationally bound star clusters that survive for at least 10-20 internal crossing times (~20-40 Myr) are relatively rare and seem to contain globular clusters formed in present-day mergers exceed omega Cen by an order of magnitude in mass, yet appear to have normal stellar initial mass functions. In the local universe, recent remnants of major gas-rich disk mergers appear as protoelliptical galaxies with subpopulations of typically 100-1000 young metal-rich globular clusters in their halos. The evidence is now strong that these "second-generation" globular clusters formed from giant molecular clouds in the merging disks, squeezed into collapse by large-scale shocks and high gas pressure rather than by high-velocity cloud-cloud collisions. Similarly, first- generation metal-poor globular clusters may have formed during cosmological reionization from low-metallicity giant molecular clouds squeezed by the universal reionization pressure.

  19. Microbubble formation from plasma polymers.

    PubMed

    Shahravan, Anaram; Yelamarty, Srinath; Matsoukas, Themis

    2012-09-27

    We document the formation of liquid-like particles in a toluene glow discharge that subsequently solidify via a process that releases hydrogen to form a solid microbubble with micrometer-size diameter, nanometer-size shell thickness, and high volume fraction, in excess of 90%. Liquid-like particles are produced in a toluene plasma under conditions that promote low degree of cross-linking (low power, high pressure). When these are transferred for observation in TEM, they are seen to transform under irradiation by the electron beam into solid bubbles with diameter of about 3 ?m. This transformation also takes place under laser irradiation of sufficient power and under heating. We present evidence that the formation of these microbubbles is due to solidification of the liquid-like precursor that is accompanied by release of hydrogen. This mechanism is supported by a geometric model that provides a quantitative description of the particle size before and after solidification. These unique stimuli-responsive particles exhibit the potential of using temperature, electron beam, or laser as a source to change their size and structure which may find application in thermal insulators, lightweight materials, and light scattering agents. PMID:22954230

  20. Cepheid Binarity and Star Formation

    NASA Astrophysics Data System (ADS)

    Remage Evans, Nancy

    Classical Cepheids are important for extragalactic distance calibration and star formation studies. A survey the fifty brightest classical Cepheids in our galaxy to search for blue companions will provide the following: An accurate determination of the percentage of Cepheid binaries with companions more massive than 2 MO and with mass ratios as small as M (COMP) / M(cep) - 1/3. This will provide valuable information on star formation for intermediate mass stars in the mass ratio and period ranges poorly sampled by other techniques. An accurate identification of Cepheids with bright companions and hence improved calibrations of temperature, reddening, and luminosity scales. A stringent test of reddening from the visual region for many Cepheids. These results must be determined from a survey of Cepheids in our galaxy since crowding in external galaxies will confuse the detection of physical companions, and orbital radial velocity material will not be available to provide additional information on mass and period distribution. While this survey builds on the 36 Cepheids already observed with IUE, it is vital to observe the 23 other stars on this program in order to obtain unbiased statistics because many of the observations in the archives were made because the stars were suspected of having companions.

  1. Supercoil Formation During DNA Melting

    NASA Astrophysics Data System (ADS)

    Sayar, Mehmet; Avsaroglu, Baris; Kabakcioglu, Alkan

    2009-03-01

    Supercoil formation plays a key role in determining the structure-function relationship in DNA. Biological and technological processes, such as protein synthesis, polymerase chain reaction, and microarrays relys on separation of the two strands in DNA, which is coupled to the unwinding of the supercoiled structure. This problem has been studied theoretically via Peyrard-Bishop and Poland-Scheraga type models, which include a simple representation of the DNA structural properties. In recent years, computational models, which provide a more realtistic representaion of DNA molecule, have been used to study the melting behavior of short DNA chains. Here, we will present a new coarse-grained model of DNA which is capable of simulating sufficiently long DNA chains for studying the supercoil formation during melting, without sacrificing the local structural properties. Our coarse-grained model successfully reproduces the local geometry of the DNA molecule, such as the 3'-5' directionality, major-minor groove structure, and the helical pitch. We will present our initial results on the dynamics of supercoiling during DNA melting.

  2. Dilatational band formation in bone

    PubMed Central

    Poundarik, Atharva A.; Diab, Tamim; Sroga, Grazyna E.; Ural, Ani; Boskey, Adele L.; Gundberg, Caren M.; Vashishth, Deepak

    2012-01-01

    Toughening in hierarchically structured materials like bone arises from the arrangement of constituent material elements and their interactions. Unlike microcracking, which entails micrometer-level separation, there is no known evidence of fracture at the level of bone’s nanostructure. Here, we show that the initiation of fracture occurs in bone at the nanometer scale by dilatational bands. Through fatigue and indentation tests and laser confocal, scanning electron, and atomic force microscopies on human and bovine bone specimens, we established that dilatational bands of the order of 100 nm form as ellipsoidal voids in between fused mineral aggregates and two adjacent proteins, osteocalcin (OC) and osteopontin (OPN). Laser microdissection and ELISA of bone microdamage support our claim that OC and OPN colocalize with dilatational bands. Fracture tests on bones from OC and/or OPN knockout mice (OC?/?, OPN?/?, OC-OPN?/?;?/?) confirm that these two proteins regulate dilatational band formation and bone matrix toughness. On the basis of these observations, we propose molecular deformation and fracture mechanics models, illustrating the role of OC and OPN in dilatational band formation, and predict that the nanometer scale of tissue organization, associated with dilatational bands, affects fracture at higher scales and determines fracture toughness of bone. PMID:23129653

  3. Coke formation in visbreaking process

    SciTech Connect

    Yan, T.Y. (Mobil Research and Development Corp., Princeton, NJ (USA))

    1987-04-01

    Visbreaking is a mild cracking process primarily used to reduce residual oil viscosity and thus decrease the amount of cutter stock required for blending to heavy fuels specification. It can also be used to produce incremental quantities of gasoline, middle distillates and catalytic cracker feeds. This process was widely used in the 1930s and 1940s and became obsolete until a few years ago. When the need for increased conversion of residues to light products became desirable, visbreaking offered economic advantages to many refining schemes - especially in Western Europe. Between 1978-1981, Exxon brought on stream seven visbreakers ranging from 1900 to 9100 tons/SD capacity. In January 1983, the world-wide visbreaking capacity was over 2 MM B/SD. The visbreaking process and its application in refinery operations have been well described. In general, the process economics improve as the process severity is increased but it is limited by coke formation in the process. For this reason, they have studied the kinetics of coke formation in the visbreaking process.

  4. Protoporphyrin formation in Rhizobium japonicum.

    PubMed Central

    Keithly, J H; Nadler, K D

    1983-01-01

    The obligately aerobic soybean root nodule bacterium Rhizobium japonicum produces large amounts of heme (iron protoporphyrin) only under low oxygen tensions, such as exist in the symbiotic root nodule. Aerobically incubated suspensions of both laboratory-cultured and symbiotic bacteria (bacteroids) metabolize delta-aminolevulinic acid to uroporphyrin, coproporphyrin, and protoporphyrin. Under anaerobic conditions, suspensions of laboratory-cultured bacteria form greatly reduced amounts of protoporphyrin from delta-aminolevulinic acid, whereas protoporphyrin formation by bacteroid suspensions is unaffected by anaerobiosis, suggesting that bacteroids form protoporphyrin under anaerobic conditions more readily than do free-living bacteria. Oxygen is the major terminal electron acceptor for coproporphyrinogen oxidation in cell-free extracts of both bacteroids and free-living bacteria. In the absence of oxygen, ATP, NADP, Mg2+, and L-methionine are required for protoporphyrin formation in vitro. In the presence of these supplements, coproporphyrinogenase activity under anaerobic conditions is 5 to 10% of that observed under aerobic conditions. Two mechanisms for coproporphyrinogen oxidation exist in R. japonicum: an oxygen-dependent process and an anaerobic oxidation in which electrons are transferred to NADP. The significance of these findings with regard to heme biosynthesis in the microaerophilic soybean root nodule is discussed. PMID:6841317

  5. An Inhibitor of PIDDosome Formation.

    PubMed

    Thompson, Ruth; Shah, Richa B; Liu, Peter H; Gupta, Yogesh K; Ando, Kiyohiro; Aggarwal, Aneel K; Sidi, Samuel

    2015-06-01

    The PIDDosome-PIDD-RAIDD-caspase-2 complex-is a proapoptotic caspase-activation platform of elusive significance. DNA damage can initiate complex assembly via ATM phosphorylation of the PIDD death domain (DD), which enables RAIDD recruitment to PIDD. In contrast, the mechanisms limiting PIDDosome formation have remained unclear. We identify the mitotic checkpoint factor BubR1 as a direct PIDDosome inhibitor, acting in a noncanonical role independent of Mad2. Following its phosphorylation by ATM at DNA breaks, "primed" PIDD relocates to kinetochores via a direct interaction with BubR1. BubR1 binds the PIDD DD, competes with RAIDD recruitment, and negates PIDDosome-mediated apoptosis after ionizing radiation. The PIDDosome thus sequentially integrates DNA damage and mitotic checkpoint signals to decide cell fate in response to genotoxic stress. We further show that by sequestering PIDD at the kinetochore, BubR1 acts to delay PIDDosome formation until the next cycle, defining a new mechanism by which cells evade apoptosis during mitosis. PMID:25936804

  6. Formation Flying for Distributed InSAR

    NASA Technical Reports Server (NTRS)

    Scharf, Daniel P.; Murray, Emmanuell A.; Ploen, Scott R.; Gromov, Konstantin G.; Chen, Curtis W.

    2006-01-01

    We consider two spacecraft flying in formation to create interferometric synthetic aperture radar (InSAR). Several candidate orbits for such in InSar formation have been previously determined based on radar performance and Keplerian orbital dynamics. However, with out active control, disturbance-induced drift can degrade radar performance and (in the worst case) cause a collision. This study evaluates the feasibility of operating the InSAR spacecraft as a formation, that is, with inner-spacecraft sensing and control. We describe the candidate InSAR orbits, design formation guidance and control architectures and algorithms, and report the (Delta)(nu) and control acceleration requirements for the candidate orbits for several tracking performance levels. As part of determining formation requirements, a formation guidance algorithm called Command Virtual Structure is introduced that can reduce the (Delta)(nu) requirements compared to standard Leader/Follower formation approaches.

  7. Early planet formation as a trigger for further planet formation

    E-print Network

    Philip J. Armitage; Brad M. S. Hansen

    1999-12-08

    Recent discoveries of extrasolar planets at small orbital radii, or with significant eccentricities, indicate that interactions between massive planets and the disks of gas and dust from which they formed are vital for determining the final shape of planetary systems. We show that if this interaction occurs at an early epoch, when the protoplanetary disc was still massive, then rapid planet growth through accretion causes an otherwise stable disc to fragment into additional planetary mass bodies when the planetary mass reaches 4-5 Jupiter masses. We suggest that such catastrophic planet formation could account for apparent differences in the mass function of massive planets and brown dwarfs, and the existence of young stars that appear to have dissipated their discs at an early epoch. Subsequent gravitational interactions will lead to planetary systems comprising a small number of massive planets in eccentric orbits.

  8. Meander formation in supraglacial streams

    NASA Astrophysics Data System (ADS)

    Karlstrom, Leif; Gajjar, Parmesh; Manga, Michael

    2013-09-01

    Meandering streams on the surface of glaciers are similar in planform geometry to meanders in alluvial and bedrock rivers, despite fundamental differences in the mechanisms and timescales of incision. We develop depth-averaged conservation equations for flow in such supraglacial channels with erodible boundaries and solve the linear stability problem for harmonic perturbations to an initially straight channel. Meander formation in supraglacial streams is driven by channel curvature, which enhances heat production and heat transfer to the surrounding ice at bend apexes. This leads to enhanced melting and lateral channel migration, with near constant channel width maintained by the competition of lateral erosion and broadscale ablation of the glacier surface. We find that meandering occurs for a wide but finite range of hydraulic and thermal parameters in both subcritical and supercritical flows and that meanders usually propagate downstream. Predicted meander wavelengths are in general agreement with an empirical scaling between supraglacial channel width and meander wavelength derived from glacial environments worldwide.

  9. Protein folding drives disulfide formation

    PubMed Central

    Kosuri, Pallav; Alegre-Cebollada, Jorge; Feng, Jason; Kaplan, Anna; Inglés-Prieto, Álvaro; Badilla, Carmen L.; Stockwell, Brent R.; Sánchez-Ruiz, José M.; Holmgren, Arne; Fernández, Julio M.

    2012-01-01

    PDI catalyzes the oxidative folding of disulfide-containing proteins. However, the sequence of reactions leading to a natively folded and oxidized protein remains unknown. Here we demonstrate a technique that enables independent measurements of disulfide formation and protein folding. We find that non-native disulfides are formed early in the folding pathway and can trigger misfolding. In contrast, a PDI domain favors native disulfides by catalyzing oxidation at a late stage of folding. We propose a model for co-translational oxidative folding wherein PDI acts as a placeholder that is relieved by the pairing of cysteines caused by substrate folding. This general mechanism can explain how PDI catalyzes oxidative folding in a variety of structurally unrelated substrates. PMID:23141538

  10. Sandpile formation by revolving rivers.

    PubMed

    Altshuler, E; Ramos, O; Martínez, E; Batista-Leyva, A J; Rivera, A; Bassler, K E

    2003-07-01

    Experimental observation of a new mechanism of sandpile formation is reported. As a steady stream of dry sand is poured onto a horizontal surface, a pile forms which has a thin river of sand on one side flowing from the apex of the pile to the edge of its base. The river rotates about the pile, depositing a new layer of sand with each revolution, thereby causing the pile to grow. For small piles the river is steady and the pile formed is smooth. For larger piles, the river becomes intermittent and the surface of the pile becomes undulating. The essential features of the system that produce the phenomenon are discussed, and the robustness of the phenomena is demonstrated with experiments using different boundary conditions and sands. PMID:12906542

  11. A study of coal formation

    SciTech Connect

    Jubert, K.; Stevens, G.; Masudi, H.

    1995-03-01

    Coal is a solid, brittle, more or less distinctly stratified, combustible, carbonaceous rock. It is being rediscovered as a reliable energy source, which, historically provided the resource base for the industrialization of the United States economy. A firm understanding of growth in coal development is important to the national energy scene so that the implications of factors influencing coal growth upon the industry`s ability to realize national energy objectives may be determined. As a result, the future of coal development will be facilitated by compiling basic facts on coal reserves, production, and utilization. In view of this, a review and assessment of facts pertaining to the nature and origin of coal is presented. The various properties and uses of coal are then described, followed by a discussion of the process of coal formation.

  12. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, A.F.

    1999-03-16

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays is disclosed. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area. 12 figs.

  13. Formation of Cosmic Dust Bunnies

    E-print Network

    Matthews, A L S; Freed, M S; Hyde, T W; Matthews, Authors Lorin S.; Hayes, Ryan L.; Freed, Michael S.; Hyde, Truell W.

    2007-01-01

    Planetary formation is an efficient process now thought to take place on a relatively short astronomical time scale. Recent observations have shown that the dust surrounding a protostar emits more efficiently at longer wavelengths as the protoplanetary disk evolves, suggesting that the dust particles are coagulating into fluffy aggregates, "much as dust bunnies form under a bed." One poorly understood problem in this coagulation process is the manner in which micron-sized, charged grains form the fractal aggregate structures now thought to be the precursors of protoplanetary disk evolution. This study examines the characteristics of such fractal aggregates formed by the collision of spherical monomers and aggregates where the charge is distributed over the aggregate structure. The aggregates are free to rotate due to collisions and dipole-dipole electrostatic interactions. Comparisons are made for different precursor size distributions and like-charged, oppositelycharged, and neutral grains.

  14. Formation of Cosmic Dust Bunnies

    E-print Network

    Lorin S. Matthews; Ryan L. Hayes; Michael S. Freed; Truell W. Hyde

    2007-01-12

    Planetary formation is an efficient process now thought to take place on a relatively short astronomical time scale. Recent observations have shown that the dust surrounding a protostar emits more efficiently at longer wavelengths as the protoplanetary disk evolves, suggesting that the dust particles are coagulating into fluffy aggregates, "much as dust bunnies form under a bed." One poorly understood problem in this coagulation process is the manner in which micron-sized, charged grains form the fractal aggregate structures now thought to be the precursors of protoplanetary disk evolution. This study examines the characteristics of such fractal aggregates formed by the collision of spherical monomers and aggregates where the charge is distributed over the aggregate structure. The aggregates are free to rotate due to collisions and dipole-dipole electrostatic interactions. Comparisons are made for different precursor size distributions and like-charged, oppositelycharged, and neutral grains.

  15. Sandpile formation by revolving rivers

    E-print Network

    E. Altshuler; O. Ramos; A. J. Batista-Leyva; A. Rivera; K. E. Bassler

    2002-06-25

    Experimental observation of a new mechanism of sandpile formation is reported. As a steady stream of dry sand is poured onto a horizontal surface, a pile forms which has a thin river of sand on one side flowing from the apex of the pile to the edge of its base. The river rotates about the pile, depositing a new layer of sand with each revolution, thereby growing the pile. For small piles the river is steady and the pile formed is smooth. For larger piles, the river becomes intermittent and the surface of the pile becomes undulating. The frequency of revolution of the river is measured as the pile grows and the results are explained with a simple scaling argument. The essential features of the system that produce the phenomena are discussed.

  16. Adaptive Optics in Star Formation

    E-print Network

    Wolfgang Brandner

    2003-09-29

    Over the past ten years, the concept of adaptive optics has evolved from early experimental stages to a standard observing tool now available at almost all major optical and near-infrared telescope facilities. Adaptive optics will also be essential in exploiting the full potential of the large optical/infrared interferometers currently under construction. Both observations with high-angular resolution and at high contrast, and with a high point source sensitivity are facilitated by adaptive optics. Among the areas which benefit most from the use of adaptive optics are studies of the circumstellar environment (envelopes, disks, outflows), substellar companions and multiple systems, and dense young stellar populations. This contribution highlights some of the recent advances in star formation studies facilitated by adaptive optics, and gives a brief tutorial on optimized observing and data reduction strategies.

  17. Pattern formation in colloidal explosions

    E-print Network

    Arthur V. Straube; Ard A. Louis; Jörg Baumgartl; Clemens Bechinger; Roel P. A. Dullens

    2011-07-23

    We study the non-equilibrium pattern formation that emerges when magnetically repelling colloids, trapped by optical tweezers, are abruptly released, forming colloidal explosions. For multiple colloids in a single trap we observe a pattern of expanding concentric rings. For colloids individually trapped in a line, we observe explosions with a zigzag pattern that persists even when magnetic interactions are much weaker than those that break the linear symmetry in equilibrium. Theory and computer simulations quantitatively describe these phenomena both in and out of equilibrium. An analysis of the mode spectrum allows us to accurately quantify the non-harmonic nature of the optical traps. Colloidal explosions provide a new way to generate well-characterized non-equilibrium behaviour in colloidal systems.

  18. Foam formation in low gravity

    NASA Technical Reports Server (NTRS)

    Wessling, Francis C.; Mcmanus, Samuel P.; Matthews, John; Patel, Darayas

    1990-01-01

    An apparatus that produced the first polyurethane foam in low gravity has been described. The chemicals were mixed together in an apparatus designed for operation in low gravity. Mixing was by means of stirring the chemicals with an electric motor and propeller in a mixing chamber. The apparatus was flown on Consort 1, the first low-gravity materials payload launched by a commercial rocket launch team. The sounding rocket flight produced over 7 min of low gravity during which a polyurethane spheroidal foam of approximately 2300 cu cm was formed. Photographs of the formation of the foam during the flight show the development of the spheroidal form. This begins as a small sphere and grows to approximately a 17-cm-diam spheroid. The apparatus will be flown again on subsequent low-gravity flights.

  19. Myc inhibition impairs autophagosome formation

    PubMed Central

    Toh, Pearl P. C.; Luo, Shouqing; Menzies, Fiona M.; Raskó, Tamás; Wanker, Erich E.; Rubinsztein, David C.

    2013-01-01

    Autophagy, a major clearance route for many long-lived proteins and organelles, has long been implicated in cancer development. Myc is a proto-oncogene often found to be deregulated in many cancers, and thus is an attractive target for design of cancer therapy. Therefore, understanding the relationship between anti-Myc strategies and autophagy will be important for development of effective therapy. Here, we show that Myc depletion inhibits autophagosome formation and impairs clearance of autophagy substrates. Myc suppression has an inhibitory effect on autophagy via reduction of c-Jun N-terminal kinase 1 (JNK1) and B-cell lymphoma 2 (Bcl2) phosphorylation. Additionally, the decrease in JNK1 phosphorylation observed with Myc knockdown is associated with a reduction in ROS production. Our data suggest that targeting Myc in cancer therapy might have the additional benefit of inhibiting autophagy in the case of therapy resistance associated with chemotherapy-induced autophagy. PMID:23933736

  20. Biomineralization: mineral formation by organisms

    NASA Astrophysics Data System (ADS)

    Addadi, Lia; Weiner, Steve

    2014-09-01

    Organisms form many different types of minerals, with diverse shapes and sizes. These minerals fulfill a variety of functions. Inspired by the late H A Lowenstam, Steve Weiner and Lia Addadi have addressed many questions that relate to the mechanisms by which biological organisms produce these mineral phases and how their structures relate to their functions. Addadi and Weiner have explored the manner in which macromolecules extracted from mineralized tissues can interact with some crystal planes and not others, how these macromolecules can be occluded inside the forming crystals residing preferentially on specific crystal planes, and how they can induce one polymorph of calcium carbonate and not another to nucleate. Addadi and Weiner have also identified a novel strategy used by the sea urchin to form its smooth and convoluted mineralized skeletal elements. The strategy involves the initial production by cells of a highly disordered mineral precursor phase in vesicles, and then the export of this so-called amorphous phase to the site of skeletal formation, where it crystallizes. This strategy is now known to be used by many different invertebrate phyla, as well as by vertebrates to build bones and teeth. One of the major current research aims of the Weiner--Addadi group is to understand the biomineralization pathways whereby ions are extracted from the environment, are transported and deposited inside cells within vesicles, how these disordered phases are then transferred to the site of skeletal formation, and finally how the so-called amorphous phase crystallizes. Biology has clearly evolved unique strategies for forming crystalline minerals. Despite more than 300 years of research in this field, many challenging questions still remain unanswered.

  1. Early Preheating and Galaxy Formation

    E-print Network

    A. J. Benson; P. Madau

    2003-07-07

    Winds from pregalactic starbursts and 'miniquasars' may pollute the IGM with metals and raise its temperature to a high adiabat, and so inhibit the formation of early galaxies. We compute the thermal history of the IGM when it experiences a period of rapid, homogeneous "preheating" at high redshifts. Measurements of the temperature of the Lyamn-alpha forest at z~3 constrain the redshift and energy of preheating, and rule out models that preheat too late or to too high a temperature. We predict galaxy luminosity functions in preheated universes. The results depend crucially on whether the baryonic smoothing scale in the IGM is computed globally, or in a local, density-dependent fashion. Using a globally averaged smoothing scale, we find that models with excessive preheating produce too few L_* and fainter galaxies, and are therefore inconsistent with observational data. A density-dependent smoothing scale requires more energetic preheating to achieve the same degree of suppression in the faint-end slope. All models, however, appear unable to explain the sharp cut-off in the luminosity function at bright magnitudes. Supernova-driven preheating scenarios tend to raise the mean metallicity of the universe well above the minimum levels observed in the Lyman-alpha clouds. We find that ionizing photon escape fractions must be significantly higher than 10% in order to explain the low inferred HI fraction at z~6. While early preheating causes strong suppression of dwarf galaxy formation we show that it is not able to reproduce the observed abundance of satellite galaxies in the Local Group in detail.

  2. Engram formation in psychiatric disorders

    PubMed Central

    Gebicke-Haerter, Peter J.

    2014-01-01

    Environmental factors substantially influence beginning and progression of mental illness, reinforcing or reducing the consequences of genetic vulnerability. Often initiated by early traumatic events, “engrams” or memories are formed that may give rise to a slow and subtle progression of psychiatric disorders. The large delay between beginning and time of onset (diagnosis) may be explained by efficient compensatory mechanisms observed in brain metabolism that use optional pathways in highly redundant molecular interactions. To this end, research has to deal with mechanisms of learning and long-term memory formation, which involves (a) epigenetic changes, (b) altered neuronal activities, and (c) changes in neuron-glia communication. On the epigenetic level, apparently DNA-methylations are more stable than histone modifications, although both closely interact. Neuronal activities basically deliver digital information, which clearly can serve as basis for memory formation (LTP). However, research in this respect has long time neglected the importance of glia. They are more actively involved in the control of neuronal activities than thought before. They can both reinforce and inhibit neuronal activities by transducing neuronal information from frequency-encoded to amplitude and frequency-modulated calcium wave patterns spreading in the glial syncytium by use of gap junctions. In this way, they serve integrative functions. In conclusion, we are dealing with two concepts of encoding information that mutually control each other and synergize: a digital (neuronal) and a wave-like (glial) computing, forming neuron-glia functional units with inbuilt feedback loops to maintain balance of excitation and inhibition. To better understand mental illness, we have to gain more insight into the dynamics of adverse environmental impact on those cellular and molecular systems. This report summarizes existing knowledge and draws some outline about further research in molecular psychiatry. PMID:24904262

  3. Star formation in active dwarf galaxies

    NASA Technical Reports Server (NTRS)

    Thronson, Harley A., Jr.; Telesco, C. M.

    1986-01-01

    Star formation and the ISM in active dwarf galaxies are studied based on data from the IRAS Point Source Catalog. The dwarf galaxies that show evidence of recent energetic star formation are generally also strong far-infrared emitters; thus, active current star formation is associated with a history of energetic star formation. A fraction of the galaxies considered here have a star formation rate that is significantly greater than the average rate in the recent past. Available gas is being consumed as efficiently in the presently active dwarfs as in the Milky Way. A primary difference between galaxies that are energetically forming stars and those that are not is the difference in gas mass, as well as the efficiency of star formation. The most important process may be the assembly of large amounts of gaseous material.

  4. Stereoregularity Drives Precipitation in Polyelectrolyte Complex Formation

    NASA Astrophysics Data System (ADS)

    Tirrell, Matthew; Perry, Sarah; Leon, Lorraine; Kade, Matthew; Priftis, Dimitris; Black, Katie; Hoffman, Kyle; Whitmer, Jonathan; Qin, Jian; de Pablo, Juan

    2014-03-01

    This study investigates the effect of stereoregularity on the formation of polypeptide-based complex formation and assembly into micelles, hydrogels and ordered phases. We demonstrate that fluid complex coacervate formation (rather than solid complex precipitation) between oppositely charged polypeptides requires at least one racemic partner in order to disrupt backbone hydrogen bonding networks and prevent the hydrophobic collapse of the polymers into compact, fibrillar secondary structures. Computer simulations bear this out and enable visualization of the molecular structure of the complexes. The ability to choose between conditions of fluid phase formation and solid phase formation is a useful tool in developing new self-assembled materials based on polyelectrolyte complex formation. Support from the Argonne National Laboratory Laboratory Research and Development Program (2011-217) is gratefully acknowledged.

  5. Formation temperatures of thermogenic and biogenic methane

    USGS Publications Warehouse

    Stolper, D.A.; Lawson, M.; Davis, C.L.; Ferreira, A.A.; Santos Neto, E. V.; Ellis, G.S.; Lewan, M.D.; Martini, A.M.; Tang, Y.; Schoell, M.; Sessions, A.L.; Eiler, J.M.

    2014-01-01

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a “clumped isotope” technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

  6. Giant Planet Formation, Evolution, and Internal Structure

    E-print Network

    Helled, Ravit; Podolak, Morris; Boley, Aaron; Meru, Farzana; Nayakshin, Sergei; Fortney, Jonathan J; Mayer, Lucio; Alibert, Yann; Boss, Alan P

    2013-01-01

    The large number of detected giant exoplanets offers the opportunity to improve our understanding of the formation mechanism, evolution, and interior structure of gas giant planets. The two main models for giant planet formation are core accretion and disk instability. There are substantial differences between these formation models, including formation timescale, favorable formation location, ideal disk properties for planetary formation, early evolution, planetary composition, etc. First, we summarize the two models including their substantial differences, advantages, and disadvantages, and suggest how theoretical models should be connected to available (and future) data. We next summarize current knowledge of the internal structures of solar- and extrasolar- giant planets. Finally, we suggest the next steps to be taken in giant planet exploration.

  7. Fibril formation from pea protein and subsequent gel formation.

    PubMed

    Munialo, Claire Darizu; Martin, Anneke H; van der Linden, Erik; de Jongh, Harmen H J

    2014-03-19

    The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20 h at pH 2.0. Following heating of pea proteins, it was observed that all of the proteins were hydrolyzed into peptides and that 50% of these peptides were assembled into fibrils. Changes on a structural level in pea proteins were studied using circular dichroism, transmission electron microscopy, and particle size analysis. During the fibril assembly process, an increase in aggregate size was observed, which coincided with an increase in thioflavin T binding, indicating the presence of ?-sheet aggregates. Fibrils made using pea proteins were more branched and curly. Gel formation of preformed fibrils was induced by slow acidification from pH 7.0 to a final pH of around pH 5.0. The ability of pea protein-based fibrillar gels to fracture during an amplitude sweep was comparable to those of soy protein and whey protein-based fibrillar gels, although gels prepared from fibrils made using pea protein and soy protein were weaker than those of whey protein. The findings show that fibrils can be prepared from pea protein, which can be incorporated into protein-based fibrillar gels. PMID:24564788

  8. Calculations of Aircraft Contrail Formation Critical Temperatures.

    NASA Astrophysics Data System (ADS)

    Schrader, Mark L.

    1997-12-01

    Forecasts of condensation trail (contrail) formation are an extremely important consideration in military aircraft operations, particularly in the operation of stealth aircraft. Some recently published works have claimed improvements in the time-tested forecast technique of H. Appleman, but the results are called into question by errors in the basic physics. This note provides a brief explanation of contrail formation theory and presents a simple derivation of the critical temperature of contrail formation for representative jet engine types.

  9. Polar format algorithm for bistatic SAR

    Microsoft Academic Search

    BRIAN D. RIGLING; RANDOLPH L. MOSES

    2004-01-01

    Matched filtering (MF) of phase history data is a mathematically ideal but computationally expensive approach to bistatic synthetic aperture radar (SAR) image formation. Fast backprojection algorithms (BPAs) for image formation have recently been shown to give improved O(N2 log2N) performance. An O(N2 log2N) bistatic polar format algorithm (PFA) based on a bistatic far-field assumption is derived. This algorithm is a

  10. TRANSIMS and the hierarchical data format

    SciTech Connect

    Bush, B.W.

    1997-06-12

    The Hierarchical Data Format (HDF) is a general-purposed scientific data format developed at the National Center for Supercomputing Applications. It supports metadata, compression, and a variety of data structures (multidimensional arrays, raster images, tables). FORTRAN 77 and ANSI C programming interfaces are available for it and a wide variety of visualization tools read HDF files. The author discusses the features of this file format and its possible uses in TRANSIMS.

  11. Formation of Water on Dust Grains

    NASA Astrophysics Data System (ADS)

    Vidali, G.; Jing, D.; He, J.; Frank, P.; Brucato, J.; de Sio, A.; Tozzetti, L.

    2011-05-01

    We studied the formation of water on dust grain analogs using isotopically labeled atomic hydrogen and oxygen beams. We detect the formation of water and intermediate products. As dust analogs, we used amorphous silicate films; for comparison, experiments done on a single crystal silicate were also carried out. The samples were characterized by in-situ infrared spectroscopy and ex-site atom force microscopy. Implications of these results on the formation of water in ISM environments will be discussed.

  12. Empirical correlation verifies true formation skin

    SciTech Connect

    Kutasov, I.M. [MultiSpectrum Technologies, Santa Monica, CA (United States)

    1995-04-03

    To determine formation (true) skin and the rate-dependent skin, a semi-theoretical equation is proposed for relating the critical value of flow rate (q{sub c}) to formation permeability, formation porosity, and gas/oil dynamic viscosity. An accurate evaluation of skin is important for designing remedial treatments or evaluating gas well productivity. Three examples illustrate the proposed equation. In all cases, the actual gas/oil flow rates are compared with the calculated critical flow rate.

  13. MWD gains as formation-evaluation tool

    SciTech Connect

    Rao, M.V.; Fontenot, J.E.

    1988-02-08

    A comparison of measuring while drilling (MWD) and wire line methods as alternatives for formation evaluation is now pertinent. The recent addition of neutron porosity and formation density logs to the MWD logging sutie has significantly advanced it as a tool for quantitative formation evaluation. Though wire line measurements are far from obsolete, their replacement by MWD is becoming more common, particularly in high-angle holes. This is the second article in a series on MWD.

  14. Towards the Rosetta Stone of planet formation

    Microsoft Academic Search

    G. Maciejewski; R. Neuhaeuser; R. Errmann; M. Mugrauer; Ch. Adam; A. Berndt; T. Eisenbeiss; S. Fiedler; Ch. Ginski; M. Hohle; U. Kramm; C. Marka; M. Moualla; T. Pribulla; St. Raetz; T. Roell; T. O. B. Schmidt; M. Seeliger; I. Spaleniak; N. Tetzlaff; L. Trepl

    2010-01-01

    Transiting exoplanets (TEPs) observed just about 10 Myrs after formation of\\u000atheir host systems may serve as the Rosetta Stone for planet formation\\u000atheories. They would give strong constraints on several aspects of planet\\u000aformation, e.g. time-scales (planet formation would then be possible within 10\\u000aMyrs), the radius of the planet could indicate whether planets form by\\u000agravitational collapse (being

  15. GLOBULAR CLUSTER FORMATION WITHIN A COSMOLOGICAL CONTEXT

    SciTech Connect

    Boley, Aaron C.; Lake, George; Read, Justin; Teyssier, Romain, E-mail: aaron.boley@gmail.co [Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, Zurich, CH-8057 (Switzerland)

    2009-11-20

    We place constraints on the formation redshifts for blue globular clusters (BGCs), independent of the details of hydrodynamics and population III star formation. The observed radial distribution of BGCs in the Milky Way Galaxy suggests that they formed in biased dark matter halos at high redshift. As a result, simulations of a approx1 Mpc box up to z approx 10 must resolve BGC formation in LAMBDACDM. We find that most halo stars could be produced from destroyed BGCs and other low-mass clusters that formed at high redshift. We present a proof-of-concept simulation that captures the formation of globular-like star clusters.

  16. GENESIS finite element mesh file format

    SciTech Connect

    Taylor, L.M.; Flanagan, D.P.; Mills-Curran, W.C.

    1986-05-01

    A new finite element mesh file format which provides a neutral interface from a mesh generation program to a finite element analysis program is described. The file format has been constructed to allow for multiple element types and flexible definition of boundary conditions. It provides for arbitrary element connectivity and attributes, so that continuum and structural elements can easily be accommodated in the same model. Element side boundary conditions as well as nodal point boundary conditions are supported. The file format is applicable to finite element models in any n-dimensional space. Both bandwidth and wavefront optimization schemes can be accommodated with the GENESIS file format. 1 ref.

  17. Dominant diffusing species during cobalt silicide formation

    NASA Astrophysics Data System (ADS)

    Comrie, C. M.; Newman, R. T.

    1996-01-01

    The dominant moving species during cobalt monosilicide and cobalt disilicide formation has been examined using a thin tantalum layer as a metal marker. The marker data obtained following the formation of CoSi from Co2Si showed that monosilicide growth was essentially due Si diffusion only. When used to study CoSi2 formation, the data indicated that silicon was also the dominant moving species during disilicide formation, although a noninsignificant amount of cobalt diffusion was also observed to take place.

  18. Treating tar sands formations with dolomite

    SciTech Connect

    Vinegar, Harold J.; Karanikas, John Michael

    2013-10-15

    A method for treating a karsted formation containing heavy hydrocarbons and dolomite includes providing heat to at least part of one or more karsted layers in the formation from one or more heaters located in the karsted layers. A temperature in at least one of the karsted layers is allowed to reach a decomposition temperature of dolomite in the formation. The dolomite is allowed to decompose and at least some hydrocarbons are produced from at least one of the karsted layers of the formation.

  19. Towards the Rosetta Stone of planet formation

    E-print Network

    Maciejewski, G; Errmann, R; Mugrauer, M; Adam, Ch; Berndt, A; Eisenbeiss, T; Fiedler, S; Ginski, Ch; Hohle, M; Kramm, U; Marka, C; Moualla, M; Pribulla, T; Raetz, St; Roell, T; Schmidt, T O B; Seeliger, M; Spaleniak, I; Tetzlaff, N; Trepl, L

    2010-01-01

    Transiting exoplanets (TEPs) observed just about 10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young) or accretion growth (being smaller when young). We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters.

  20. Towards the Rosetta Stone of planet formation

    NASA Astrophysics Data System (ADS)

    Maciejewski, G.; Neuhäuser, R.; Errmann, R.; Mugrauer, M.; Adam, Ch.; Berndt, A.; Eisenbeiss, T.; Fiedler, S.; Ginski, Ch.; Hohle, M.; Kramm, U.; Marka, C.; Moualla, M.; Pribulla, T.; Raetz, St.; Roell, T.; Schmidt, T. O. B.; Seeliger, M.; Spaleniak, I.; Tetzlaff, N.; Trepl, L.

    2011-02-01

    Transiting exoplanets (TEPs) observed just ~10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young) or accretion growth (being smaller when young). We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters.