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Sample records for bow mountains southeastern

  1. Drill-hole data, drill-site geology, and geochemical data from the study of Precambrian uraniferous conglomerates of the Medicine Bow Mountains and Sierra Madre of southeastern Wyoming

    International Nuclear Information System (INIS)

    This volume is presented as a companion to Volume 1: The Geology and Uranium Potential of Precambrian Conglomerates in the Medicine Bow Mountains and Sierra Madre of Southeastern Wyoming; and to Volume 3: Uranium Assessment for Precambrian Pebble Conglomerates in Southeastern Wyoming. Volume 1 summarized the geologic setting and geologic and geochemical characteristics of uranium-bearing conglomerates in Precambrian metasedimentary rocks of southeastern Wyoming. Volume 3 is a geostatistical resource estimate of U and Th in quartz-pebble conglomerates. This volume contains supporting geochemical data, lithologic logs from 48 drill holes in Precambrian rocks of the Medicine Bow Mountains and Sierra Madre, and drill site geologic maps and cross-sections from most of the holes

  2. Depositional environments of the coal-bearing Mist Mountain formation, Eagle Mountain, southeastern Canadian Rocky mountains

    Energy Technology Data Exchange (ETDEWEB)

    Dunlop, R.L.; Bustin, R.M. (University of British Columbia, Vancouver, BC (Canada). Department of Geological Sciences)

    1987-12-01

    Fifteen major coal seams have been identified at the Mist Mountain formation at Eagle Mountain in southeastern British Columbia. In this paper a detailed three-dimensional analysis of the sedimentology of the Mist Mountain formation is undertaken, with particular reference to factors controlling lateral and vertical distribution of major coal seams and coal quality. Data was based on examination of 200 drill hole samples. 32 refs., 20 figs.

  3. Bowing in the Right Direction: Hiland Mountain Correctional Center Women's String Orchestra Programme

    Science.gov (United States)

    Warfield, Duane

    2010-01-01

    The Hiland Mountain Correctional Center, a 400-bed facility for multi-level adult female offenders in Eagle River, Alaska, offers a unique educational programme to its prisoners: an orchestra. Founded in 2003, by volunteer Pati Crofut, orchestra membership grew from eight to 22 female offenders between 2003 and 2009. Crofut has devoted her time…

  4. Paleoseismic investigations of Stagecoach Road fault, southeastern Yucca Mountain, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Menges, C.M.; Oswald, J.A.; Coe, J.A.; Lundstrom, S.C.; Paces, J.B.; Mahan, S.A.; Widmann, B.; Murray, M.

    1998-04-01

    This report summarizes the results of paleoseismic investigations at two trenches (SCR-T1 and SCR-T3) excavated across the Stagecoach Road (SCR) fault at the southeastern margin of Yucca Mountain. The results of these studies are based on detailed mapping or logging of geologic and structural relationships exposed in trench walls, combined with descriptions of lithologic units, associated soils, and fault-related deformation. The ages of trench deposits are determined directly from geochronologic dating of selected units and soils, supplemented by stratigraphic and soil correlations with other surficial deposits in the Yucca Mountain area. The time boundaries used in this report for subdivision of the Quaternary period are listed in a table. These data and interpretations are used to identify the number, amounts, timing, and approximately lengths of late to middle Quaternary (less than 200 ka) surface-faulting events associated with paleoearthquakes at the trench sites. This displacement history forms the basis for calculating paleoearthquake recurrence intervals and fault-slip rates for the Stagecoach Road fault and allows comparison with fault behavior on other Quaternary faults at or near Yucca Mountain.

  5. Altitudinal distribution of birds in a mountainous region in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Francisco Mallet-Rodrigues

    2010-08-01

    Full Text Available We studied the altitudinal distribution of 426 bird species in the Serra dos Órgãos, a mountainous region in southeastern Brazil. Thirty-four localities were visited between 1991 and 2009. Our study revealed a decline in bird species richness with elevation, although a smaller number of species was recorded at lower altitudes (below 300 m possibly due to local extinctions caused by the intense human occupation of the region. A less diverse avifauna was found above 2,000 m, with only one species (Caprimulgus longirostris recorded exclusively in this altitudinal range. Most endemic species were found between 300 and 1,200 m, but the endemism was more significant at higher altitudes. Nearly half of the birds found above 1,400 m were endemic species. Most of the threatened species from the state of Rio de Janeiro recorded in our study were found below 1,200 m, but no significant difference was found between the proportions of threatened species among different altitudinal ranges. Species of seventeen genera have exhibited some replacement (sometimes with partial overlap along altitudinal gradients.

  6. New inventory of glaciers in southeastern part of the Eastern Sayan Mountains

    Directory of Open Access Journals (Sweden)

    E. Yu. Osipov

    2013-01-01

    Full Text Available Satellite images with high (Quick Bird, 2006, WorldView-1, 2008, 0.5–0.6 m and middle (Landsat-7 ETM +, 2001, 15–30 m resolution were used to map contemporary glaciers on two mountain peaks of south-eastern part of East Sayan Ridge – Munky Sardyk (3491 m a.s.l. and Topographov (3089 m a.s.l.. Topographic maps of 1978 and 1981 and Landsat-7 images (summer 2001 were used to assess glacier changes during second half of XX century. Modern terminal and lateral moraines near glacier snouts were used to reconstruct former outlines during the end of the Little Ice Age (middle of XIX century. Also SRTM data and GPS-surveys in Munku-Sardyk area were applied to measure glacier altitudes. GIS technologies allowed forming digital glacier data base with attribute information and new inventory was made. Totally 13 glaciers with area of 5.1 km² were investigated and mapped. Glaciers are located in vertical range from 2800–3490 m a.s.l. (Munku-Sardyk area and 2340–2950 m a.s.l. (Topographov area. Firn line on glaciers vary from 2540 to 3110 m a.s.l., rising to the southeast. On average, over the past 160 years (since the end of the Little Ice Age glaciers have significantly decreased. Ice area has decreased by 49%, length has diminished by 570 m, the glacier snouts has risen by 124 m. Analysis of regional climate data shows that the rate of deglaciation is well correlated with summer temperatures increasing in the second half of XX century, especially in 1980–1990s. A tendency to recover glacier mass balance was revealed during the last decade based on climatic data.

  7. Application of multi-temporal landform analysis in landslide susceptibility assessment for mountainous highway - a case study in southeastern Taiwan

    Science.gov (United States)

    Liu-Xuan, Jian; Wei-Kai, Huang; Po-Shen, Lin

    2016-04-01

    This study divided a coastal mountainous highway into small sections with slope unit, plot the multi-temporal landslide inventories, and analyze the relationships between the revegetation areas of the existing landslide and newly activated landslide to calculate landslide status Index (LSI). The RI represents the multi-temporal status of landslide status in each slope unit; three statuses and their representing colors were defined in this study. Red representing slope unit with continuously landslides, yellow for those with previous landslide but stable and revegetating, green are those without landslides. The regression lines became one of the parameters in establishing landslide status map. The study area, 407K to 439K of Provincial Highway No. 9, located in southeastern Taiwan and is the most important transport corridor connecting southern Taiwan and the east coast. In 2009 this mountainous highway was hit by Typhoon Morakot and several landslides, debris slides were triggered in the study area. The debris blocked the traffic and residential communities alone the highway became isolated. To this date some section of the highway still suffer from landslide hazard and transportation had to be temporarily interrupted during some occasions. The landslide status map of this transport corridor was established combining the result of field investigation, remote sensing interpretation, and the regression lines of LSI. The preliminary result shows that out of the 258 slope units, 13 (5%) showing continuous landslides, 44 (17%) became stable and revegetating. The result of this study could provide better information for mountainous highway safety management.

  8. Field-trip guide to the southeastern foothills of the Santa Cruz Mountains in Santa Clara County, California

    Science.gov (United States)

    Stoffer, Philip W.; Messina, Paula

    2002-01-01

    This field trip is an introduction to the geology of the southeastern foothills of the Santa Cruz Mountains in southern Santa Clara County. Seven stops include four short hikes to access rock exposures and views of the foothills east of Loma Prieta Peak between Gilroy and San José. Field-trip destinations highlight the dominant rock types of the "Franciscan assemblage" including outcrops of serpentinite, basalt, limestone, ribbon chert, graywacke sandstone, and shale. General discussions include how the rocks formed, and how tectonism and stream erosion have changed the landscape through time. All field trip stops are on public land; most are near reservoir dams of the Santa Clara Valley Water District. In addition, stops include examination of an Ohlone Indian heritage site and the New Almaden Mining Museum.

  9. Ship bow waves

    Institute of Scientific and Technical Information of China (English)

    NOBLESSE Francis; DELHOMMEAU Gerard; LIU Hua; WAN De-cheng; YANG Chi

    2013-01-01

    The bow wave generated by a ship hull that advances at constant speed in calm water is considered.The bow wave only depends on the shape of the ship bow (not on the hull geometry aft of the bow wave).This basic property makes it possible to determine the bow waves generated by a canonical family of ship bows defined in terms of relatively few parameters.Fast ships with fine bows generate overturning bow waves that consist of detached thin sheets of water,which are mostly steady until they hit the main free surface and undergo turbulent breaking up and diffusion.However,slow ships with blunt bows create highly unsteady and turbulent breaking bow waves.These two alternative flow regimes are due to a nonlinear constraint related to the Bernoulli relation at the free surface.Recent results about the overturning and breaking bow wave regimes,and the boundary that divides these two basic flow regimes,are reviewed.Questions and conjectures about the energy of breaking ship bow waves,and free-surface effects on flow circulation,are also noted.

  10. Fuel rod bowing

    International Nuclear Information System (INIS)

    The purpose of this investigation was to quantify the extent of fuel rod bowing in Westinghouse pressurized water reactors and to assess the effects of fuel rod bowing on plant safety and reliability. An empirical bow correlation was developed based on data from irradiated assemblies. Analyses conducted with these conservative empirical predictions show that: (1) generically identified DNBR margins are adequate to offset DNBR reductions due to rod bow, (2) the present design practice of increasing the highest calculated core peaking factor is sufficient to account for all deviations, including the effects of rod bow, and (3) fretting and corrosion of bowed rods are negligible. These conclusions indicate that fuel rod bowing results in no impact on plant safety or reliability

  11. In situ cosmogenic 10Be dating of the Quaternary glaciations in the southern Shaluli Mountain on the Southeastern Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    WANG; Jian; Raisbeck; Grand; XU; Xiaobin; Yiou; Francios; BAI; Shibiao

    2006-01-01

    It is generally considered that four-times ice age happened during the Quaternary epoch on the Tibetan Plateau.However,the research on the chronology of the four-times ice age is far from enough.The Shaluli Mountain on the Southeastern Tibetan Plateau is an ideal place for plaeo-glacier study,because there are abundant Quaternary glacial remains there.This paper discusses the ages of the Quaternary glaciations,based on the exposure dating of roche moutonnée,moraines and glacial erosion surfaces using in situ cosmogenic isotopes 10Be.It is found that the exposure age of the roche moutonnée at Tuershan is 15 ka,corresponding to Stage 2 of the deep-sea oxygen isotope,suggesting that the roche moutonnée at Tuershan is formed in the last glacial maximum.The exposure age of glacial erosion surface at Laolinkou is 130-160 ka,corresponding to Stage 6 of the deep-sea oxygen isotope.The oldest end moraine at Kuzhaori may form at 421-766 kaBP,corresponding to Stages 12-18 of the deep-sea oxygen isotope.In accordance with the climate characteristic of stages 12,14,16 and 18 reflected by the deep-sea oxygen isotope,polar ice cores and loess sequence,the oldest end moraine at Kuzhaori may form at stage 12 or stage 16,the latter is more possible.

  12. Diagenesis of Viola Limestone (Middle and Upper Ordovician), southeastern Arbuckle Mountains, Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Grammer, G.M.

    1983-03-01

    The Viola Limestone in the Arbuckle Mountains was deposited on a carbonate ramp within the southern Oklahoma aulacogen. A complex diagenetic history has occluded virtually all primary porosity within the Viola. Petrographic evidence suggests that the following approximate sequence of diagenetic events has occurred; (1) microboring and subsequent micritization of bioclasts to form micrite envelopes; (2) very early submarine cementation that bound the loosely sorted allochems and partly occluded porosity, characterized by drusy overgrowths on trilobite and brachiopod fragments, bladed, void-filling cement, and turbid, inclusion-rich syntaxial overgrowths on pelmatozoan fragments; (3) initial compaction evidenced by local fracturing of elongate bioclasts; (4) neomorphism, including the inversion of aragonitic allochems to calcite and the recrystallization of micrite to microspar and pseudospar in the presence of low-salinity pore fluids; (5) freshwater cementation that filled virtually all remaining pore space; (6) selective dolomitization; (7) silicification, including the formation of chert nodules and the replacement of bioclasts and calcite cements by microgranular quartz and/or lutecite; (8) compaction and pressure solution, probably due to deep burial, characterized by nonsutured seam stylolites, sutured seam stylolites oriented subparallel to bedding, and sutured grain boundaries; and (9) tectonically imposed pressure solution indicated by sutured seam stylolites oriented at high angles to bedding that developed during the late Paleozoic deformation of the Arbuckle Mountain. The Viola Limestone is known as a reservoir rock and possible source unit for hydrocarbons throughout much of south-central Oklahoma.

  13. Accelerated loss of alpine glaciers in the Kodar Mountains, south-eastern Siberia

    Science.gov (United States)

    Stokes, Chris R.; Shahgedanova, Maria; Evans, Ian S.; Popovnin, Victor V.

    2013-02-01

    The recession of mountain glaciers around the world has been linked to anthropogenic climate change and small glaciers (e.g. change can be modulated by non-climatic factors such as topography and debris cover and there remain a number of regions where their recent change has evaded scrutiny. This paper presents results of the first multi-year remote sensing survey of glaciers in the Kodar Mountains, the only glaciers in SE Siberia, which we compare to previous glacier inventories from this continental setting that reported total glacier areas of 18.8 km2 in ca. 1963 (12.6 km2 of exposed ice) and 15.5 km2 in 1974 (12 km2 of exposed ice). Mapping their debris-covered termini is difficult but delineation of debris-free ice on Landsat imagery reveals 34 glaciers with a total area of 11.72 ± 0.72 km2 in 1995, followed by a reduction to 9.53 ± 0.29 km2 in 2001 and 7.01 ± 0.23 km2 in 2010. This represents a ~ 44% decrease in exposed glacier ice between ca. 1963 and 2010, but with 40% lost since 1995 and with individual glaciers losing as much as 93% of their exposed ice. Thus, although continental glaciers are generally thought to be less sensitive than their maritime counterparts, a recent acceleration in shrinkage of exposed ice has taken place and we note its coincidence with a strong summer warming trend in the region initiated at the start of the 1980s. Whilst smaller and shorter glaciers have, proportionally, tended to shrink more rapidly, we find no statistically significant relationship between shrinkage and elevation characteristics, aspect or solar radiation. This is probably due to the small sample size, limited elevation range, and topographic setting of the glaciers in deep valleys-heads. Furthermore, many of the glaciers possess debris-covered termini and it is likely that the ablation of buried ice is lagging the shrinkage of exposed ice, such that a growth in the proportion of debris cover is occurring, as observed elsewhere. If recent trends continue

  14. Logs and paleoseismic interpretations from trenches 14C and 14D on the Bow Ridge fault, northeastern Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Detailed studies of trenches 14D and 14C on the Bow Ridge fault indicate two to three displacements and long recurrence intervals during the middle to late Quaternary. The main trace of the fault is marked by a thick (20--40 centimeters wide) subvertical shear zone coated with multiple carbonate-silica laminae and several generations of fine-grained fissure-fill debris. Exposed in the trenches is a vertically stacked sequence of thin (0.3--1.5 meters thick) fine-grained colluvial, alluvial, and eolian deposits that commonly contain smaller wedge-shaped units or several weakly to strongly developed buried paleosols, or both. The two to three surface-rupture events are recognized at discrete stratigraphic intervals in the sequence based on (1) incremental up-section decreases in offset of marker horizons, (b) upward terminations of shear zones, fissure fills, and fractures, and (c) the position of small scarp-derived colluvial wedges deposited adjacent to the fault above downfaulted marker horizons. Preferred estimates of the vertical displacement per event are 12 and 40 centimeters. Left-oblique striations are observed on carbonate fault laminae, which, if tectonic in origin, increase the vertical displacement by factors of 1.1 to 1.7, yielding preferred net slip displacements per event of 13 to 70 centimeters. Thermoluminescence ages of 48 ± 20 and 132 ± 23 thousand years bracket the ages of the events, which probably occurred near the bounding ages of the time interval. These age constraints suggest long, average recurrence intervals between the three events of 75 to 210 ky; the preferred values range between 100 to 140 ky. The small net cumulative displacement of two dated reference horizons yield very low fault slip rates of 0.002 to 0.007 millimeters per year; the preferred value is 0.003 millimeters per year

  15. Logs and paleoseismic interpretations from trenches 14C and 14D on the Bow Ridge fault, northeastern Yucca Mountain, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Menges, C.M.; Taylor, E.M.; Vadurro, G.; Oswald, J.A.; Cress, R.; Murray, M.; Lundstrom, S.C.; Paces, J.B.; Mahan, S.A.

    1997-12-31

    Detailed studies of trenches 14D and 14C on the Bow Ridge fault indicate two to three displacements and long recurrence intervals during the middle to late Quaternary. The main trace of the fault is marked by a thick (20--40 centimeters wide) subvertical shear zone coated with multiple carbonate-silica laminae and several generations of fine-grained fissure-fill debris. Exposed in the trenches is a vertically stacked sequence of thin (0.3--1.5 meters thick) fine-grained colluvial, alluvial, and eolian deposits that commonly contain smaller wedge-shaped units or several weakly to strongly developed buried paleosols, or both. The two to three surface-rupture events are recognized at discrete stratigraphic intervals in the sequence based on (1) incremental up-section decreases in offset of marker horizons, (b) upward terminations of shear zones, fissure fills, and fractures, and (c) the position of small scarp-derived colluvial wedges deposited adjacent to the fault above downfaulted marker horizons. Preferred estimates of the vertical displacement per event are 12 and 40 centimeters. Left-oblique striations are observed on carbonate fault laminae, which, if tectonic in origin, increase the vertical displacement by factors of 1.1 to 1.7, yielding preferred net slip displacements per event of 13 to 70 centimeters. Thermoluminescence ages of 48 {+-} 20 and 132 {+-} 23 thousand years bracket the ages of the events, which probably occurred near the bounding ages of the time interval. These age constraints suggest long, average recurrence intervals between the three events of 75 to 210 ky; the preferred values range between 100 to 140 ky. The small net cumulative displacement of two dated reference horizons yield very low fault slip rates of 0.002 to 0.007 millimeters per year; the preferred value is 0.003 millimeters per year.

  16. Bow Crushing Forces

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1996-01-01

    The purpose of these notes is to present a basis for the estimation of the internal collision forces between conventinal merchant vessels and large volume offshore structures in the form of gravity-supported offshore installations and bridges crossing international shipping routes.The main emphas...... is on the presentation of impact loads on fixed offshore structures due to bow collisions. The crushing forces are determined as functions of vessels size, vessels speed, bow profile, collision angles and eccentric impacts....

  17. Status of aeromagnetic survey coverage of Yucca Mountain and vicinity to a radius of about 140 kilometers, southwestern Nevada and southeastern California, 1992

    International Nuclear Information System (INIS)

    Fifty aeromagnetic surveys in the southwestern part of Nevada and the southeastern part of California have been evaluated to assess the quality and coverage of aeromagnetic data within 140 kilometers (km) of a potential nuclear waste repository at Yucca Mountain, Nevada. The compilation shows that all the study area is covered by aeromagnetic surveys, but in some areas, particularly in the Death Valley region, new surveys flown with closer flight line spacing and lower elevations than the existing coverage are needed. In addition, the California part of the study area needs to be analytically continued downward to 305 meters (m) above ground level to provide a consistent data set for interpretation of subsurface geologic structures

  18. Bow shock: Power aspects

    Science.gov (United States)

    Sedykh, P. A.

    2014-07-01

    It is clear that the primary energy source for magnetospheric processes is the solar wind, but the process of energy transfer from the solar wind into the magnetosphere, or rather, to convecting magnetospheric plasma, appears to be rather complicated. Bow shock is a powerful transformer of the solar wind kinetic energy into the gas dynamic and electromagnetic energy. A jump of the magnetic field tangential component at front crossing means that the front carries an electric current. The solar wind kinetic energy partly transforms to gas kinetic and electromagnetic energy during its passage through the bow shock front. The transition layer (magnetosheath) can use part of this energy for accelerating of plasma, but can conversely spend part its kinetic energy on the electric power generation, which afterwards may be used by the magnetosphere. Thereby, transition layer can be both consumer (sink) and generator (source) of electric power depending upon special conditions. The direction of the current behind the bow shock front depends on the sign of the IMF Bz-component. It is this electric current which sets convection of plasma in motion.

  19. Mountaineering

    Institute of Scientific and Technical Information of China (English)

    潘步东

    2005-01-01

    Most young people enjoy some forms of physical activities.It may be walking,cycling or swimming,or in wither,skating or skiing.It may be a game of some kind,football,hockey(曲棍球),golf,or tennis.Perhaps it may be mountaineering.

  20. Measurement of ambient aerosol hydration state at Great Smoky Mountains National Park in the southeastern United States

    Directory of Open Access Journals (Sweden)

    N. F. Taylor

    2011-12-01

    Full Text Available We present results from two field deployments of a unique tandem differential mobility analyzer (TDMA configuration with two primary capabilities: identifying alternative stable or meta-stable ambient aerosol hydration states associated with hysteresis in aerosol hydration behavior and determining the actual Ambient hydration State (AS-TDMA. This data set is the first to fully classify the ambient hydration state of aerosols despite recognition that hydration state significantly impacts the roles of aerosols in climate, visibility and heterogeneous chemistry. The AS-TDMA was installed at a site in eastern Tennessee on the border of Great Smoky Mountains National Park for projects during the summer of 2006 and winter of 2007–2008. During the summer, 12% of the aerosols sampled in continuous AS-TDMA measurements were found to posses two possible hydration states under ambient conditions. In every case, the more hydrated of the possible states was occupied. The remaining 88% did not posses multiple possible states. In continuous measurements during the winter, 49% of the aerosols sampled possessed two possible ambient hydration states; the remainder possessed only one. Of those aerosols with multiple possible ambient hydration states, 65% occupied the more hydrated state; 35% occupied the less hydrated state. This seasonal contrast is supported by differences in the fine particulate (PM2.5 composition and ambient RH as measured during the two study periods. In addition to seasonal summaries, this work includes case studies depicting the variation of hydration state with changing atmospheric conditions.

  1. Post-glacial landscape response to climate variability in the southeastern San Juan Mountains of Colorado, USA

    Science.gov (United States)

    Johnson, Bradley G.; Eppes, Martha Cary; Diemer, John A.; Jiménez-Moreno, Gonzalo; Layzell, Anthony L.

    2011-11-01

    Geomorphic mapping in the upper Conejos River Valley of the San Juan Mountains has shown that three distinct periods of aggradation have occurred since the end of the last glacial maximum (LGM). The first occurred during the Pleistocene-Holocene transition (~ 12.5-9.5 ka) and is interpreted as paraglacial landscape response to deglaciation after the LGM. Evidence of the second period of aggradation is limited but indicates a small pulse of sedimentation at ~ 5.5 ka. A third, more broadly identifiable period of sedimentation occurred in the late Holocene (~ 2.2-1 ka). The latest two periods of aggradation are concurrent with increases in the frequency of climate change in the region suggesting that Holocene alpine and sub-alpine landscapes respond more to rapid changes in climate than to large singular climatic swings. Soil development and radiocarbon dating indicate that hillslopes were stable during the Holocene even while aggradation was occurring in valley bottoms. Thus, we can conclude that erosion does not occur equally throughout the landscape but is focused upslope of headwater streams, along tributary channels, or on ridge tops. This is in contrast to some models which assume equal erosion in headwater basins.

  2. Uranium in Precambrian granitic rocks of the St. Francois Mountains, southeastern Missouri, with comments on uranium resource potential

    International Nuclear Information System (INIS)

    Red granites of the St. Francois Mountains are highly radioactive and contain 4 to 34 ppM uranium. The most radioactive is the Graniteville Granite which contains an average of 16.9 ppM U and 42.6 ppM Th. The Butler Hill and Breadtray Granites also contain anomalous amounts, averaging 6.2 and 5.6 ppM U and 23.5 and 20.5 ppM Th respectively. Other Precambrian granitic rocks have normal concentrations of U and Th. Fission track ''maps'' indicate that high concentrations of uranium are associated with magnetite in the red granites; this uranium is presumed to be readily leachable by hydrothermal or supergene solutions. No uranium minerals or ore grade concentrations of uranium were observed in or near the granites, but there are conceptual reasons for the possible existence of uranium deposits in intragranitic veins and onlapping Cambrian-Ordovician sedimentary rocks. Although the red granites constitute a good potential source of uranium, there is not much evidence for uranium having been mobilized. Identification of features such as lamprophyre dikes and ''episyenite'' alteration, or sedimentary rocks containing reductants, would be of value for exploration and would permit more favorable resource appraisal

  3. Measurement of ambient aerosol hydration state at Great Smoky Mountains National Park in the Southeastern United States

    Directory of Open Access Journals (Sweden)

    N. F. Taylor

    2011-08-01

    Full Text Available We present results from two field deployments of a unique tandem differential mobility analyzer (TDMA configuration with two primary capabilities: identifying alternative stable or meta-stable ambient aerosol hydration states associated with hysteresis in aerosol hydration behavior and determining the actual Ambient hydration State (AS-TDMA. This data set is the first to fully classify the ambient hydration state of aerosols despite recognition that hydration state significantly impacts the roles of aerosols in climate, visibility and heterogeneous chemistry. The AS-TDMA was installed at a site in eastern Tennessee on the border of Great Smoky Mountains National Park for projects during the summer of 2006 and winter of 2007–2008. During the summer, 12 % of the aerosols sampled in continuous AS-TDMA measurements were found to posses two possible hydration states under ambient conditions. In every case, the more hydrated of the possible states was occupied. The remaining 88 % did not posses multiple possible states. In continuous measurements during the winter, 49 % of the aerosols sampled possessed two possible ambient hydration states; the remainder possessed only one. Of those aerosols with multiple possible ambient hydration states, 65 % occupied the more hydrated state; 35 % occupied the less hydrated state. This seasonal contrast is supported by differences in the fine particulate (PM2.5 composition and ambient RH as measured during the two study periods. In addition to seasonal summaries, this work includes case studies depicting the variation of hydration state with changing atmospheric conditions.

  4. The Early Jurassic Bokan Mountain peralkaline granitic complex (southeastern Alaska): geochemistry, petrogenesis and rare-metal mineralization

    Science.gov (United States)

    Dostal, Jaroslav; Kontak, Daniel J.; Karl, Susan M.

    2014-01-01

    The Early Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska, cross-cuts Paleozoic igneous and metasedimentary rocks of the Alexander terrane of the North American Cordillera and was emplaced during a rifting event. The complex is a circular body (~3 km in diameter) of peralkaline granitic composition that has a core of arfvedsonite granite surrounded by aegirine granite. All the rock-forming minerals typically record a two-stage growth history and aegirine and arfvedsonite were the last major phases to crystalize from the magma. The Bokan granites and related dikes have SiO2 from 72 to 78 wt. %, high iron (FeO (tot) ~3-4.5 wt. %) and alkali (8-10 wt.%) concentrations with high FeO(tot)/(FeO(tot)+MgO) ratios (typically >0.95) and the molar Al2O3/(Na2O+K2O) ratio Nd values which are indicative of a mantle signature. The parent magma is inferred to be derived from an earlier metasomatized lithospheric mantle by low degrees of partial melting and generated the Bokan granitic melt through extensive fractional crystallization. The Bokan complex hosts significant rare-metal (REE, Y, U, Th, Nb) mineralization that is related to the late-stage crystallization history of the complex which involved the overlap of emplacement of felsic dikes, including pegmatite bodies, and generation of orthomagmatic fluids. The abundances of REE, HFSE, U and Th as well as Pb and Nd isotopic values of the pluton and dikes were modified by orthomagmatic hydrothermal fluids highly enriched in the strongly incompatible trace elements, which also escaped along zones of structural weakness to generate rare-metal mineralization. The latter was deposited in two stages: the first relates to the latest stage of magma emplacement and is associated with felsic dikes that intruded along the faults and shear deformations, whereas the second stage involved ingress of hydrothermal fluids that both remobilized and enriched the initial

  5. The Early Jurassic Bokan Mountain peralkaline granitic complex (southeastern Alaska): Geochemistry, petrogenesis and rare-metal mineralization

    Science.gov (United States)

    Dostal, Jaroslav; Kontak, Daniel J.; Karl, Susan M.

    2014-08-01

    The Early Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska, cross-cuts Paleozoic igneous and metasedimentary rocks of the Alexander terrane of the North American Cordillera and was emplaced during a rifting event. The complex is a circular body (~ 3 km in diameter) of peralkaline granitic composition that has a core of arfvedsonite granite surrounded by aegirine granite. All the rock-forming minerals typically record a two-stage growth history and aegirine and arfvedsonite were the last major phases to crystallize from the magma. The Bokan granites and related dikes have SiO2 from 72 to 78 wt.%, high iron (FeO (tot) ~ 3-4.5 wt.%) and alkali (8-10 wt.%) concentrations with high FeO(tot)/(FeO(tot) + MgO) ratios (typically > 0.95) and the molar Al2O3/(Na2O + K2O) ratio metal (REE, Y, U, Th, Nb) mineralization that is related to the late-stage crystallization history of the complex which involved the overlap of emplacement of felsic dikes, including pegmatite bodies, and generation of orthomagmatic fluids. The abundances of REE, HFSE, U and Th as well as Pb and Nd isotopic values of the pluton and dikes were modified by orthomagmatic hydrothermal fluids highly enriched in the strongly incompatible trace elements, which also escaped along zones of structural weakness to generate rare-metal mineralization. The latter was deposited in two stages: the first relates to the latest stage of magma emplacement and is associated with felsic dikes that intruded along the faults and shear deformations, whereas the second stage involved ingress of hydrothermal fluids that both remobilized and enriched the initial magmatic mineralization. Mineralization is mostly composed of “new” minerals. Fluorine complexing played a role during the transportation of REE and HFSE in hydrothermal fluids and oxygen isotopes in the granites and quartz veins negate the significant incursion of an external fluid and support a

  6. Statistical modeling of violin bowing parameter contours

    OpenAIRE

    Maestre G??mez, Esteban

    2009-01-01

    We present a framework for modeling right-hand gestures in bowed-string instrument playing, applied to violin. Nearly non-intrusive sensing techniques allow for accurate acquisition of relevant timbre-related bowing gesture parameter cues. We model the temporal contour of bow transversal velocity, bow pressing force, and bow-bridge distance as sequences of short segments, in particular B??ezier cubic curve segments. Considering different articulations, dynamics, and contexts, a number of n...

  7. Earth's bow shock: Power aspects.

    Science.gov (United States)

    Sedykh, Pavel

    2012-07-01

    The process of energy transfer from the solar wind into the magnetosphere, or rather, to convecting magnetospheric plasma, appears to be rather complicated. The bow shock front is the main converter of solar wind kinetic energy into electromagnetic energy [Ponomarev, Sedykh, J. of Atm. Solar-Terr. Phys. V. 68. 2006; Ponomarev, Sedykh et al., Geomagn. and Aeron., 2009]. Solar wind undergoes significant changes in its parameters during its passing through the bow shock front. Indeed, at the bow point, when crossing the front, the magnetic field tangential component and magnetic energy density increase by factors of almost 4 and approximately 15, respectively. In describing the bow shock, we followed [Whang, 1987; Ponomarev et al., 2006]. A jump of the magnetic field tangential component when crossing the bow shock front means that the front carries an electric current. It is possible to show that electric current is diverging in this layer, that is the front is the generator of the current. Since plasma with magnetic field passes through the bow shock front, electric field arises in the front reference system. Thus, the bow shock front is a source of electric power. The direction of electric current behind the bow shock front depends on the sign of the IMF Bz-component. It is this current which sets convection in motion. Energetically, this external current is necessary for maintaining convection of plasma in the inhomogeneous system (geomagnetosphere). The generator at the bow shock front can be a sufficient source of power for supplying energy to substorm processes [Sedykh, Sun and Geosphere, 2011]. The sign of power does not depend on the IMF sign, and energy flux is always directed into the magnetosphere. The magnitude of the power is different and is realized in different regions of the magnetosphere depending on the IMF direction. When the Bz-component is negative, the electric convection field is larger, with the anticonvection field being smaller, than for

  8. Stability Analysis of Bow Shocks

    Science.gov (United States)

    Buren, David Van

    1995-01-01

    We present a linear stability analysis of bow shocks created by the interaction of a spherical wind moving with respect to its surrounding medium. The bounding shocks are assumed isothermal and with Mach number M = infinity. Following Soker (1990) we study the evolution of short wavelength perturbations. We find that the motion is unstable in this limit. Moreover, the ratio of the wind velocity v(sub w) to the star velocity v(sub *) characterizes the stability properties. Bow shocks with fast winds for which v(sub *)/v(sub w)>1.

  9. Some aspects of vocal fold bowing.

    Science.gov (United States)

    Tanaka, S; Hirano, M; Chijiwa, K

    1994-05-01

    Bowing of the vocal fold frequently occurs in patients with vocal fold paralysis (VFP), those with sulcus vocalis, and those who have had laser surgery. Additionally, there are vocal folds that present bowing with no noticeable organic lesion. For the purpose of investigating the causes and mechanisms of vocal fold bowing, consecutive fiberscopic videorecordings of 127 patients with VFP, 33 with sulcus vocalis, 33 with laser surgery, and 33 with dysphonia having no clinically noticeable organic lesion were reviewed. Sixty-nine percent of the paralyzed vocal folds had bowing, and the occurrence of bowing was significantly related to the activity of the thyroarytenoid muscle as measured by electromyography. The cricothyroid activity had no significant relationship to vocal fold bowing. All vocal folds with sulcus presented with bowing. Thirty-five percent of the vocal folds that had had laser surgery had bowing. The extent of tissue removal was closely related to the occurrence of bowing. Twelve cases with no organic lesion had vocal fold bowing. Of these 12 patients, 8 were male and 9 were older than 60 years. Some aging process in the mucosa was presumed to be the cause of the bowing in this age group of patients without clinically noticeable organic lesions. Causes of vocal fold bowing in the younger group of patients without organic lesions were not determined in this study.

  10. Dielectric Bow-tie Nanocavity

    CERN Document Server

    Lu, Qijing; Zou, Chang-Ling

    2013-01-01

    We propose a novel dielectric bow-tie nanocavity consisting of two tip-to-tip opposite triangle semiconductor nanowires, whose end faces are coated by silver nanofilms. Based on the advantages of the dielectric slot and tip structures, and the high reflectivity from the silver mirror, light can be confined in this nanocavity with low loss. We demonstrate that the mode excited in this nanocavity has a deep subwavelength mode volume of 2.8*10^-4 um3 and a high quality factor of 4.9*10^4 (401.3), consequently an ultrahigh Purcell factor of 1.6*10^7 (1.36*10^5), at 4.5 K (300 K) around the resonance wavelength of 1550 nm. This dielectric bow-tie nanocavity may find applications for integrated nanophotonic circuits, such as high-efficiency single photon source, thresholdless nanolaser, and cavity QED strong coupling experiments.

  11. Astrospheres and Stellar Bow shocks

    Science.gov (United States)

    Van Marle, Allard Jan

    2016-07-01

    As stars evolve, they deliver feedback to the surrounding medium in the form of stellar wind and radiation. These shape the surrounding matter, forming what is called an astrosphere, a sphere of influence in which the star dominates the morphology and composition of the surrounding medium. Astrospheres are fascinating objects. Because they are formed through the interaction between the stellar feedback and the interstellar gas, they can tell us a great deal about both. Furthermore, because they are shaped over time they provide us with a window into the past. This is of particular interest for the study of stellar evolution, because the astrosphere reflects changes in the properties of the stellar wind, which relate directly to the properties of the star. A special sub-class of astrospheres, the stellar bow shocks, occur when the progenitor star moves through the surrounding medium at supersonic speed. Because the properties of the bow shock relate directly to both the stellar wind and the interstellar medium, the shape and size of the bow shock can be used to determine these properties. Using state-of-the-art numerical codes, it is possible to simulate the interaction between the stellar wind and radiation and the interstellar medium. These results can then be compared to observations. They can also be used to predict the type of observations that are best suited to study these objects. In this fashion computational and observational astronomy can support each other in their efforts to gain a better understanding of stars and their environment.

  12. Regeneration after 8 years in artificial canopy gaps in mountain ash (Eucalyptus regnans F. Muell.) forest in south-eastern Australia

    NARCIS (Netherlands)

    Meer, van der P.J.; Dignan, P.

    2007-01-01

    We report on a study of regeneration of Mountain Ash (Eucalyptus regnans) forest in S.E. Australia in artificially created canopy gaps (0.01¿2 ha) and clearfelled coupes (4¿27 ha) with different seedbed treatments. Treatments were applied in 1988, 1989, and 1990. Our results are based on measurement

  13. Dielectric Bow-tie Nanocavity

    OpenAIRE

    Lu, Qijing; Shu, Fang-Jie; Zou, Chang-Ling

    2013-01-01

    We propose a novel dielectric bow-tie nanocavity consisting of two tip-to-tip opposite triangle semiconductor nanowires, whose end faces are coated by silver nanofilms. Based on the advantages of the dielectric slot and tip structures, and the high reflectivity from the silver mirror, light can be confined in this nanocavity with low loss. We demonstrate that the mode excited in this nanocavity has a deep subwavelength mode volume of 2.8*10^-4 um3 and a high quality factor of 4.9*10^4 (401.3)...

  14. Ground-Dwelling Arthropod Communities of a Sky Island Mountain Range in Southeastern Arizona, USA: Obtaining a Baseline for Assessing the Effects of Climate Change.

    Directory of Open Access Journals (Sweden)

    Wallace M Meyer

    Full Text Available The few studies that have addressed past effects of climate change on species distributions have mostly focused on plants due to the rarity of historical faunal baselines. However, hyperdiverse groups like Arthropoda are vital to monitor in order to understand climate change impacts on biodiversity. This is the first investigation of ground-dwelling arthropod (GDA assemblages along the full elevation gradient of a mountain range in the Madrean Sky Island Region, establishing a baseline for monitoring future changes in GDA biodiversity. To determine how GDA assemblages relate to elevation, season, abiotic variables, and corresponding biomes, GDA were collected for two weeks in both spring (May and summer (September 2011 in the Santa Catalina Mountains, Arizona, using pitfall traps at 66 sites in six distinct upland (non-riparian/non-wet canyon biomes. Four arthropod taxa: (1 beetles (Coleoptera, (2 spiders (Araneae, (3 grasshoppers and crickets (Orthoptera, and (4 millipedes and centipedes (Myriapoda were assessed together and separately to determine if there are similar patterns across taxonomic groups. We collected 335 species of GDA: 192/3793 (species/specimens Coleoptera, 102/1329 Araneae, 25/523 Orthoptera, and 16/697 Myriapoda. GDA assemblages differed among all biomes and between seasons. Fifty-three percent (178 species and 76% (254 species of all GDA species were found in only one biome and during only one season, respectively. While composition of arthropod assemblages is tied to biome and season, individual groups do not show fully concordant patterns. Seventeen percent of the GDA species occurred only in the two highest-elevation biomes (Pine and Mixed Conifer Forests. Because these high elevation biomes are most threatened by climate change and they harbor a large percentage of unique arthropod species (11-25% depending on taxon, significant loss in arthropod diversity is likely in the Santa Catalina Mountains and other isolated

  15. Ground-Dwelling Arthropod Communities of a Sky Island Mountain Range in Southeastern Arizona, USA: Obtaining a Baseline for Assessing the Effects of Climate Change.

    Science.gov (United States)

    Meyer, Wallace M; Eble, Jeffrey A; Franklin, Kimberly; McManus, Reilly B; Brantley, Sandra L; Henkel, Jeff; Marek, Paul E; Hall, W Eugene; Olson, Carl A; McInroy, Ryan; Bernal Loaiza, Emmanuel M; Brusca, Richard C; Moore, Wendy

    2015-01-01

    The few studies that have addressed past effects of climate change on species distributions have mostly focused on plants due to the rarity of historical faunal baselines. However, hyperdiverse groups like Arthropoda are vital to monitor in order to understand climate change impacts on biodiversity. This is the first investigation of ground-dwelling arthropod (GDA) assemblages along the full elevation gradient of a mountain range in the Madrean Sky Island Region, establishing a baseline for monitoring future changes in GDA biodiversity. To determine how GDA assemblages relate to elevation, season, abiotic variables, and corresponding biomes, GDA were collected for two weeks in both spring (May) and summer (September) 2011 in the Santa Catalina Mountains, Arizona, using pitfall traps at 66 sites in six distinct upland (non-riparian/non-wet canyon) biomes. Four arthropod taxa: (1) beetles (Coleoptera), (2) spiders (Araneae), (3) grasshoppers and crickets (Orthoptera), and (4) millipedes and centipedes (Myriapoda) were assessed together and separately to determine if there are similar patterns across taxonomic groups. We collected 335 species of GDA: 192/3793 (species/specimens) Coleoptera, 102/1329 Araneae, 25/523 Orthoptera, and 16/697 Myriapoda. GDA assemblages differed among all biomes and between seasons. Fifty-three percent (178 species) and 76% (254 species) of all GDA species were found in only one biome and during only one season, respectively. While composition of arthropod assemblages is tied to biome and season, individual groups do not show fully concordant patterns. Seventeen percent of the GDA species occurred only in the two highest-elevation biomes (Pine and Mixed Conifer Forests). Because these high elevation biomes are most threatened by climate change and they harbor a large percentage of unique arthropod species (11-25% depending on taxon), significant loss in arthropod diversity is likely in the Santa Catalina Mountains and other isolated

  16. Ground-Dwelling Arthropod Communities of a Sky Island Mountain Range in Southeastern Arizona, USA: Obtaining a Baseline for Assessing the Effects of Climate Change.

    Science.gov (United States)

    Meyer, Wallace M; Eble, Jeffrey A; Franklin, Kimberly; McManus, Reilly B; Brantley, Sandra L; Henkel, Jeff; Marek, Paul E; Hall, W Eugene; Olson, Carl A; McInroy, Ryan; Bernal Loaiza, Emmanuel M; Brusca, Richard C; Moore, Wendy

    2015-01-01

    The few studies that have addressed past effects of climate change on species distributions have mostly focused on plants due to the rarity of historical faunal baselines. However, hyperdiverse groups like Arthropoda are vital to monitor in order to understand climate change impacts on biodiversity. This is the first investigation of ground-dwelling arthropod (GDA) assemblages along the full elevation gradient of a mountain range in the Madrean Sky Island Region, establishing a baseline for monitoring future changes in GDA biodiversity. To determine how GDA assemblages relate to elevation, season, abiotic variables, and corresponding biomes, GDA were collected for two weeks in both spring (May) and summer (September) 2011 in the Santa Catalina Mountains, Arizona, using pitfall traps at 66 sites in six distinct upland (non-riparian/non-wet canyon) biomes. Four arthropod taxa: (1) beetles (Coleoptera), (2) spiders (Araneae), (3) grasshoppers and crickets (Orthoptera), and (4) millipedes and centipedes (Myriapoda) were assessed together and separately to determine if there are similar patterns across taxonomic groups. We collected 335 species of GDA: 192/3793 (species/specimens) Coleoptera, 102/1329 Araneae, 25/523 Orthoptera, and 16/697 Myriapoda. GDA assemblages differed among all biomes and between seasons. Fifty-three percent (178 species) and 76% (254 species) of all GDA species were found in only one biome and during only one season, respectively. While composition of arthropod assemblages is tied to biome and season, individual groups do not show fully concordant patterns. Seventeen percent of the GDA species occurred only in the two highest-elevation biomes (Pine and Mixed Conifer Forests). Because these high elevation biomes are most threatened by climate change and they harbor a large percentage of unique arthropod species (11-25% depending on taxon), significant loss in arthropod diversity is likely in the Santa Catalina Mountains and other isolated

  17. 75 FR 40820 - City of Broken Bow, Oklahoma; Project No. 12470-001-Oklahoma Broken Bow Re-Regulation Dam...

    Science.gov (United States)

    2010-07-14

    ... Energy Regulatory Commission City of Broken Bow, Oklahoma; Project No. 12470-001--Oklahoma Broken Bow Re... included in, or eligible for inclusion in, the National Register of Historic Places at the Broken Bow Re..., 2010, for the Broken Bow Re-Regulation Dam Hydroelectric Project No. 12470 is revised to add...

  18. 75 FR 33802 - City of Broken Bow, OK; Broken Bow Re-Regulation Dam; Hydropower Project; Notice of Proposed...

    Science.gov (United States)

    2010-06-15

    ... Energy Regulatory Commission City of Broken Bow, OK; Broken Bow Re-Regulation Dam; Hydropower Project... eligible for inclusion in, the National Register of Historic Places at the Broken Bow Re-Regulation Dam... the Broken Bow Re-Regulation Dam Hydropower Project would be fulfilled through the...

  19. Dielectric bow-tie nanocavity.

    Science.gov (United States)

    Lu, Qijing; Shu, Fang-Jie; Zou, Chang-Ling

    2013-12-15

    We propose a novel dielectric bow-tie (DBT) nanocavity consisting of two opposing tip-to-tip triangle semiconductor nanowires, whose end faces are coated by silver nanofilms. Based on the advantages of the dielectric slot and tip structures, and the high reflectivity of the silver mirror, light can be confined in this nanocavity with low loss. We demonstrate that at 4.5 K (300 K) around the resonance wavelength of 1550 nm, the mode excited in this nanocavity has a deep subwavelength mode volume of 2.8×10(-4) μm³ and a high quality factor of 4.9×10(4) (401.3), corresponding to an ultrahigh Purcell factor of 1.6×10(7) (1.36×10(5)). This DBT nanocavity may find applications for integrated nanophotonic circuits, such as high-efficiency single photon sources, thresholdless nanolasers, and strong coupling in cavity quantum electrodynamics experiments. PMID:24322245

  20. 鄂东南低山丘陵区五节芒防除试验%Experiment on Control of Miscanthus floridulus in the Low Mountains and Hilly Area in Southeastern Hubei

    Institute of Scientific and Technical Information of China (English)

    孙拥康; 汤景明; 冯祥成; 陈文武

    2015-01-01

    为筛选出防除五节芒效果较好的除草剂,利用农达(41%草甘膦)、百草枯、精喹禾灵三种除草剂,开展鄂东南低山丘陵区五节芒防除试验,结果表明:三种除草剂除草效果与施药剂量、施药时间呈正比时,三种除草剂均可有效控制五节芒生长;但综合施药和成本情况,确定出农达(41%草甘膦)为防治五节芒优选除草剂,施药剂量以3000 mL•hm-2为宜。%In order to select better herbicide for Control Miscanthus floridulus ,we carried out the experiments on controlling Miscanthus floridulus control experiments with roundu (41% glyphosate),paraquat and 10% quizalofop-p-ethyl in the low mountains and hilly area in southeastern Hubei.The results showed that the weed control effect of these three kinds of herbicide were proportional to their dose and spraying duration.Three kinds of herbicide could all control its growth.And the pesticide dose and the cost synthetically determined that roundu(41% glyphosate)and within the application dosage in 3 000 mL•hm-2 was the optimal selection.

  1. Assessment of potential migration of radionuclides and trace elements from the White Mesa uranium mill to the Ute Mountain Ute Reservation and surrounding areas, southeastern Utah

    Science.gov (United States)

    Naftz, David L.; Ranalli, Anthony J.; Rowland, Ryan C.; Marston, Thomas M.

    2011-01-01

    In 2007, the Ute Mountain Ute Tribe requested that the U.S. Environmental Protection Agency and U.S. Geological Survey conduct an independent evaluation of potential offsite migration of radionuclides and selected trace elements associated with the ore storage and milling process at an active uranium mill site near White Mesa, Utah. Specific objectives of this study were (1) to determine recharge sources and residence times of groundwater surrounding the mill site, (2) to determine the current concentrations of uranium and associated trace elements in groundwater surrounding the mill site, (3) to differentiate natural and anthropogenic contaminant sources to groundwater resources surrounding the mill site, (4) to assess the solubility and potential for offsite transport of uranium-bearing minerals in groundwater surrounding the mill site, and (5) to use stream sediment and plant material samples from areas surrounding the mill site to identify potential areas of offsite contamination and likely contaminant sources. The results of age-dating methods and an evaluation of groundwater recharge temperatures using dissolved-gas samples indicate that groundwater sampled in wells in the surficial aquifer in the vicinity of the mill is recharged locally by precipitation. Tritium/helium age dating methods found a "modern day" apparent age in water samples collected from springs in the study area surrounding the mill. This apparent age indicates localized recharge sources that potentially include artificial recharge of seepage from constructed wildlife refuge ponds near the mill. The stable oxygen isotope-ratio, delta oxygen-18, or δ(18O/16O), known as δ18O, and hydrogen isotope-ratio, delta deuterium, or δ(2H/1H), known as δD, data indicate that water discharging from Entrance Spring is isotopically enriched by evaporation and has a similar isotopic fingerprint as water from Recapture Reservoir, which is used as facilities water on the mill site. Water from Recapture

  2. Modelling the bending/bowing of composite beams such as nuclear fuel: The BOW code

    Energy Technology Data Exchange (ETDEWEB)

    Tayal, M. (Atomic Energy of Canada Ltd., Sheridan Park, Ontario. CANDU Operations)

    1989-09-01

    Arrays of tubes are used in many engineered structures, such as in nuclear fuel bundles and in steam generators. The tubes are bend (bow) due to in-service temperatures and loads. Assessments of bowing of nuclear fuel elements can help demonstrate the integrity of fuel and of surrounding components, as a function of operating conditions such as channel power. The BOW code calculates the bending of composite beams such as fuel elements, due to gradients of temperature and due to hydraulic forces. The deflections and rotations are calculated in both lateral directions, for given conditions of temperatures. Wet and dry operation of the sheath can be simulated. BOW accounts for the following physical phenomena: circumferential and axial variations in the temperatures of the sheath and of the pellet; cracking of pellets; grip and slip between the pellets and the sheath; hydraulic drag; restraints from endplates, from neighbouring elements, and from the pressure-tube; gravity; concentric or eccentric welds between endcaps and endplate; neutron flux gradients; and variations of material properties with temperature. The code is based on fundamental principles of mechanics. The governing equations are solved numerically using the finite element method. Several comparisons with closed-form equations show that the solutions of BOW are accurate. BOW's predictions for initial in-reactor bow are also consistent with two post-irradiation measurements. (orig.).

  3. Assessment of potential migration of radionuclides and trace elements from the White Mesa uranium mill to the Ute Mountain Ute Reservation and surrounding areas, southeastern Utah

    Science.gov (United States)

    Naftz, David L.; Ranalli, Anthony J.; Rowland, Ryan C.; Marston, Thomas M.

    2011-01-01

    In 2007, the Ute Mountain Ute Tribe requested that the U.S. Environmental Protection Agency and U.S. Geological Survey conduct an independent evaluation of potential offsite migration of radionuclides and selected trace elements associated with the ore storage and milling process at an active uranium mill site near White Mesa, Utah. Specific objectives of this study were (1) to determine recharge sources and residence times of groundwater surrounding the mill site, (2) to determine the current concentrations of uranium and associated trace elements in groundwater surrounding the mill site, (3) to differentiate natural and anthropogenic contaminant sources to groundwater resources surrounding the mill site, (4) to assess the solubility and potential for offsite transport of uranium-bearing minerals in groundwater surrounding the mill site, and (5) to use stream sediment and plant material samples from areas surrounding the mill site to identify potential areas of offsite contamination and likely contaminant sources. The results of age-dating methods and an evaluation of groundwater recharge temperatures using dissolved-gas samples indicate that groundwater sampled in wells in the surficial aquifer in the vicinity of the mill is recharged locally by precipitation. Tritium/helium age dating methods found a "modern day" apparent age in water samples collected from springs in the study area surrounding the mill. This apparent age indicates localized recharge sources that potentially include artificial recharge of seepage from constructed wildlife refuge ponds near the mill. The stable oxygen isotope-ratio, delta oxygen-18, or δ(18O/16O), known as δ18O, and hydrogen isotope-ratio, delta deuterium, or δ(2H/1H), known as δD, data indicate that water discharging from Entrance Spring is isotopically enriched by evaporation and has a similar isotopic fingerprint as water from Recapture Reservoir, which is used as facilities water on the mill site. Water from Recapture

  4. The Statics of the Traditional Hungarian Composite Reflex Bow

    Directory of Open Access Journals (Sweden)

    Sándor Horváth

    2006-04-01

    Full Text Available The operation of the Hungarian bow raises several fascinating mechanicalquestions. To answer these questions a good number of experiments and calculations needto be made, moreover the mechanical model of the bow is needed to be prepared whichappropriately confirm the results of experiments. Teachers in the Bánki Donát MechanicalEngineering College of Budapest Polytechnic set up a small laboratory in 1997 in order tostudy and measure the physical characteristics of traditional bows. The mechanicalanalysis of bows is based on the experiments gained in the laboratory and the results ofmeasurements. The knowledge acquired about the mechanical model of bows facilitates notonly the analysis of the traditional Hungarian bow, but also provides a good foundation forthe comparison from the technical point of view of various composite reflex bows belongingto different historic ethnic groups.

  5. Suprathermal electrons at Saturn's bow shock

    CERN Document Server

    Masters, A; Sergis, N; Stawarz, L; Fujimoto, M; Coates, A J; Dougherty, M K

    2016-01-01

    The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless plasma shocks frequently encountered by spacecraft in the solar wind are generally far weaker (lower Mach number) than these SNR shocks. However, the Cassini spacecraft has shown that the shock standing in the solar wind sunward of Saturn (Saturn's bow shock) can occasionally reach this high-Mach number astrophysical regime. In this regime Cassini has provided the first in situ evidence for electron acceleration under quasi-parallel upstream magnetic conditions. Here we present the full picture of suprathermal electrons at Saturn's bow shock revealed by Cassini. The downstream thermal electron distribution is resolved in all data taken by the low-energy electron detector (CAPS-ELS, 18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically onl...

  6. Bow shock formation in a complex plasma.

    Science.gov (United States)

    Saitou, Y; Nakamura, Y; Kamimura, T; Ishihara, O

    2012-02-10

    A bow shock is observed in a two-dimensional supersonic flow of charged microparticles in a complex plasma. A thin conducting needle is used to make a potential barrier as an obstacle for the particle flow in the complex plasma. The flow is generated and the flow velocity is controlled by changing a tilt angle of the device under the gravitational force. A void, microparticle-free region, is formed around the potential barrier surrounding the obstacle. The flow is bent around the leading edge of the void and forms an arcuate structure when the flow is supersonic. The structure is characterized by the bow shock as confirmed by a polytropic hydrodynamic theory as well as numerical simulation. PMID:22401079

  7. A survey for Hα pulsar bow shocks

    International Nuclear Information System (INIS)

    We report on a survey for Hα bow shock emission around nearby γ-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around Fermi pulsar PSR J1741–2054, we now report Hα structures around two additional γ-ray pulsars, PSR J2030+4415 and PSR J1509–5850. These are the first known examples of Hα nebulae with pre-ionization halos. With new measurements, we show that a simple analytic model can account for the angular size and flux of the bow shocks' apices. The latter, in particular, provides a new pulsar probe and indicates large moments of inertia and smaller distances than previously assumed in several cases. In particular, we show that the re-measured PSR J0437–4715 shock flux implies I = (1.7 ± 0.2) × 1045/(f HIsin i) g cm2. We also derive a distance d ≈ 0.72 kpc for the γ-ray only pulsar PSR J2030+4415 and revised distances for PSRs J1959+2048 (1.4 kpc) and J2555+6535 (∼1 kpc), smaller than the conventional DM-estimated values. Finally, we report upper limits for 94 additional LAT pulsars. An estimate of the survey sensitivity indicates that for a warm neutral medium filling factor φWNM ∼ 0.3 there should be a total of approximately nine Hα bow shocks in our LAT-targeted survey; given that seven such objects are now known, a much larger φWNM seems problematic.

  8. SHRIMP Geochronology of Volcanics of the Zhangjiakou and Yixian Formations, Northern Hebei Province, with a Discussion on the Age of the Xing'anling Group of the Great Hinggan Mountains and Volcanic Strata of the Southeastern Coastal Area of China

    Institute of Scientific and Technical Information of China (English)

    NIU Baogui; HE Zhengjun; SONG Biao; REN Jishun; XIAO Liwei

    2004-01-01

    A zircon U-Pb geochronological study on the volcanic rocks reveals that both of the Zhangjiakou and Yixian Formations, northern Hebei Province, are of the Early Cretaceous, with ages of 135-130 Ma and 129-120 Ma,respectively. It is pointed out that the ages of sedimentary basins and volcanism in the northern Hebei -western Liaoning area become younger from west to east, i. e. the volcanism of the Luanping Basin commenced at c. 135 Ma, the Luotuo Mount area of the Chengde Basin c. 130 Ma, and western Liaoning c. 128 Ma. With a correlation of geochronological stratigraphy and biostratigraphy, we deduce that the Xing'anling Group, which comprises the Great Hinggan Mountains volcanic rock belt in eastern China, is predominantly of the early-middle Early Cretaceous, while the Jiande and Shimaoshan Groups and their equivalents, which form the volcanic rock belt in the southeastern coast area of China, are of the mid-late Early Cretaceous, and both the Jehol and Jiande Biotas are of the Early Cretaceous, not Late Jurassic or Late Jurassic-Early Cretaceous. Combining the characteristics of the volcanic rocks and, in a large area, hiatus in the strata of the Late Jurassic or Late Jurassic-early Early Cretaceous between the formations mentioned above and the underlying sequences, we can make the conclusion that, in the Late Jurassic-early Early Cretaceous, the eastern China region was of high relief or plateau, where widespread post-orogenic volcanic series of the Early Cretaceous obviously became younger from inland in the west to continental margin in the east. This is not the result of an oceanward accretion of the subduction belt between the Paleo-Pacific ocean plate and the Asian continent, but rather reflects the extension feature, i.e. after the closure of the Paleo-Pacific ocean, the Paleo-Pacific ancient continent collided with the Asian continent and reached the peak of orogenesis, and then the compression waned and resulted in the retreating of the post

  9. Rotationnal and translational waves in a bowed string

    CERN Document Server

    Bavu, E; Placais, P Y; Smith, J; Wolfe, J; Bavu, Eric; Yew, Manfred; Placais, Pierre-Yves; Smith, John; Wolfe, Joe

    2005-01-01

    We measure and compare the rotational and transverse velocity of a bowed string. When bowed by an experienced player, the torsional motion is phase-locked to the transverse waves, producing highly periodic motion. The spectrum of the torsional motion includes the fundamental and harmonics of the transverse wave, with strong formants at the natural frequencies of the torsional standing waves in the whole string. Volunteers with no experience on bowed string instruments, however, often produced non-periodic motion. We present sound files of both the transverse and torsional velocity signals of well-bowed strings. The torsional signal has not only the pitch of the transverse signal, but it sounds recognisably like a bowed string, probably because of its rich harmonic structure and the transients and amplitude envelope produced by bowing.

  10. The sacred weapon: bow and arrow combat in Iran

    Directory of Open Access Journals (Sweden)

    Manouchehr Moshtagh Khorasani

    2012-07-01

    Full Text Available The following article presents the development of the bow and arrow, and its important role in the history of Iran. The bow always played an important role not only on the battlefield, but also in hunting. It was also considered as a sacred weapon and additionally a royal symbol. Bow and arrow were considered as a superior weapon in comparison with other types of weapons because one could fight with them at a safer distance as one offered by swords, maces and axes. The first part of the article presents a short history of the bow in Iran. Based on historical Persian manuscripts, the next part explains the structure of the composite bow and the materials used for making it. The third part describes some types of bows based on the material, place of production, the usage, and bow type based on the length of the bow and the arrows. The following part talks about different types of arrows based on morphology of arrowheads, the type of plume/feather, the material of the shaft, the material of the arrowhead, the length of arrows, the target of arrows, the place of production of arrowheads and terms for describing its different features of an arrowhead. Then, the article talks about different types of thumb rings, bowstrings, quivers and bow cases and arrow guides for shooting short arrows. The next part discusses different principles of archery as explained in Persian manuscripts. Finally the article describes different archery targets.

  11. Discovery of a bow shock around Vela X-1

    CERN Document Server

    Kaper, L; Augusteijn, T; Goudfrooij, P; Patat, N; Zijlstra, A A; Waters, R; Kaper, Lex; Loon, Jacco van; Augusteijn, Thomas; Goudfrooij, Paul; Patat, Nando; Zijlstra, Albert; Waters, Rens

    1996-01-01

    We report the discovery of a symmetric bow shock around the well-known high-mass X-ray binary (HMXB) Vela X-1. Wind bow shocks are a ubiquitous phenomenon around OB-runaway stars, but now such a structure is found around a HMXB. The presence of a bow shock indicates that the system has a high (supersonic) velocity with respect to the interstellar medium. From the symmetry of the bow shock, the direction of motion and, moreover, the origin and age of the system can be derived. Our observation supports Blaauw's scenario for the formation of an OB-runaway star by the supernova explosion of the binary companion.

  12. Coordination in fast repetitive violin-bowing patterns.

    Directory of Open Access Journals (Sweden)

    Erwin Schoonderwaldt

    Full Text Available We present a study of coordination behavior in complex violin-bowing patterns involving simultaneous bow changes (reversal of bowing direction and string crossings (changing from one string to another. Twenty-two violinists (8 advanced amateurs, 8 students with violin as major subject, and 6 elite professionals participated in the experiment. We investigated the influence of a variety of performance conditions (specific bowing patterns, dynamic level, tempo, and transposition and level of expertise on coordination behavior (a.o., relative phase and amplitude and stability. It was found that the general coordination behavior was highly consistent, characterized by a systematic phase lead of bow inclination over bow velocity of about 15° (i.e., string crossings were consistently timed earlier than bow changes. Within similar conditions, a high individual consistency was found, whereas the inter-individual agreement was considerably less. Furthermore, systematic influences of performance conditions on coordination behavior and stability were found, which could be partly explained in terms of particular performance constraints. Concerning level of expertise, only subtle differences were found, the student and professional groups (higher level of expertise showing a slightly higher stability than the amateur group (lower level of expertise. The general coordination behavior as observed in the current study showed a high agreement with perceptual preferences reported in an earlier study to similar bowing patterns, implying that complex bowing trajectories for an important part emerge from auditory-motor interaction.

  13. Size effects in band gap bowing in nitride semiconducting alloys

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede;

    2011-01-01

    Chemical and size contributions to the band gap bowing of nitride semiconducting alloys (InxGa1-xN, InxAl1-xN, and AlxGa1-xN) are analyzed. It is shown that the band gap deformation potentials of the binary constituents determine the gap bowing in the ternary alloys. The particularly large gap...

  14. Evolution of bow-tie architectures in biology.

    Directory of Open Access Journals (Sweden)

    Tamar Friedlander

    2015-03-01

    Full Text Available Bow-tie or hourglass structure is a common architectural feature found in many biological systems. A bow-tie in a multi-layered structure occurs when intermediate layers have much fewer components than the input and output layers. Examples include metabolism where a handful of building blocks mediate between multiple input nutrients and multiple output biomass components, and signaling networks where information from numerous receptor types passes through a small set of signaling pathways to regulate multiple output genes. Little is known, however, about how bow-tie architectures evolve. Here, we address the evolution of bow-tie architectures using simulations of multi-layered systems evolving to fulfill a given input-output goal. We find that bow-ties spontaneously evolve when the information in the evolutionary goal can be compressed. Mathematically speaking, bow-ties evolve when the rank of the input-output matrix describing the evolutionary goal is deficient. The maximal compression possible (the rank of the goal determines the size of the narrowest part of the network-that is the bow-tie. A further requirement is that a process is active to reduce the number of links in the network, such as product-rule mutations, otherwise a non-bow-tie solution is found in the evolutionary simulations. This offers a mechanism to understand a common architectural principle of biological systems, and a way to quantitate the effective rank of the goals under which they evolved.

  15. Evolution of bow-tie architectures in biology.

    Science.gov (United States)

    Friedlander, Tamar; Mayo, Avraham E; Tlusty, Tsvi; Alon, Uri

    2015-03-01

    Bow-tie or hourglass structure is a common architectural feature found in many biological systems. A bow-tie in a multi-layered structure occurs when intermediate layers have much fewer components than the input and output layers. Examples include metabolism where a handful of building blocks mediate between multiple input nutrients and multiple output biomass components, and signaling networks where information from numerous receptor types passes through a small set of signaling pathways to regulate multiple output genes. Little is known, however, about how bow-tie architectures evolve. Here, we address the evolution of bow-tie architectures using simulations of multi-layered systems evolving to fulfill a given input-output goal. We find that bow-ties spontaneously evolve when the information in the evolutionary goal can be compressed. Mathematically speaking, bow-ties evolve when the rank of the input-output matrix describing the evolutionary goal is deficient. The maximal compression possible (the rank of the goal) determines the size of the narrowest part of the network-that is the bow-tie. A further requirement is that a process is active to reduce the number of links in the network, such as product-rule mutations, otherwise a non-bow-tie solution is found in the evolutionary simulations. This offers a mechanism to understand a common architectural principle of biological systems, and a way to quantitate the effective rank of the goals under which they evolved. PMID:25798588

  16. Suprathermal Electrons at Saturn's Bow Shock

    Science.gov (United States)

    Masters, A.; Sulaiman, A. H.; Sergis, N.; Stawarz, L.; Fujimoto, M.; Coates, A. J.; Dougherty, M. K.

    2016-07-01

    The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless plasma shocks frequently encountered by spacecraft in the solar wind are generally far weaker (lower Mach number) than these SNR shocks. However, the Cassini spacecraft has shown that the shock standing in the solar wind sunward of Saturn (Saturn's bow shock) can occasionally reach this high-Mach number astrophysical regime. In this regime Cassini has provided the first in situ evidence for electron acceleration under quasi-parallel upstream magnetic conditions. Here we present the full picture of suprathermal electrons at Saturn's bow shock revealed by Cassini. The downstream thermal electron distribution is resolved in all data taken by the low-energy electron detector (CAPS-ELS, 18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically only the lowest energy channels (whistler waves at the shock front, and becomes possible for all upstream magnetic field orientations at high Mach numbers like those of the strong shocks around young SNRs. A future dedicated study will analyze the rare crossings with evidence for relativistic electrons (up to ˜1 MeV).

  17. Parmotrema hydrium, a new species of Parmeliaceae in southeastern Brazil

    OpenAIRE

    Michel Navarro Benatti; Maria Gernert; Imke Schmitt

    2013-01-01

    Parmotrema hydrium is a new lichen species discovered during a survey of Parmeliaceae in the Cantareira mountain range of southeastern Brazil. In its medullary chemistry, the species contains several fatty acids and other substances, including small amounts of atranorin, typically restricted to the soralia and young lobes.

  18. Parmotrema hydrium, a new species of Parmeliaceae in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Michel Navarro Benatti

    2013-12-01

    Full Text Available Parmotrema hydrium is a new lichen species discovered during a survey of Parmeliaceae in the Cantareira mountain range of southeastern Brazil. In its medullary chemistry, the species contains several fatty acids and other substances, including small amounts of atranorin, typically restricted to the soralia and young lobes.

  19. A Study on the Pometia tomentosa Community of Tropical Seasonal Rain Forest in Dahei Mountain, Lixian River Watershed,Southeastern Yunnan%滇东南李仙江大黑山热带季节性雨林番龙眼群落研究

    Institute of Scientific and Technical Information of China (English)

    周虹霞; 朱华; 王洪; 肖文祥

    2001-01-01

    滇东南绿春县李仙江大黑山番龙眼群落以无患子科的番龙眼和苏木科的无忧花为乔木层优势种,外貌以单叶、纸质、全缘、渐尖、中叶为主的常绿大、中高位芽植物组成为特征,层间木质藤本较丰富,属一种热带北缘的热带季节性雨林类型。该群落物种组成复杂,动态结构稳定,处于生长期。%The Pometia tomentosa forest in Dahei Mountain, Lixian RiverWatershed, southeastern Yunnan,is dominated by Pometia tomentosa and Saraca dives, and is charactered by evergreen megaphaenerophytes and mesophaenerophytes with simple ,chartaceous and entire mesophylls. With the conspicuous similarity on ecological and floristic characters to tropical rain forest of SE Asia, the forest in Dahei Mountain is considered as a type of tropical seasonal rain forest in the northern margin of tropical Asia. Furthermore, the distribution of trees in DBH class, the individual/ tree species relation and the frequency of tree species are enumerated.

  20. Mini Mountain Wear

    Institute of Scientific and Technical Information of China (English)

    PHOTOCOME

    2005-01-01

    THE depths of the southeastern Guizhou Province mountains are inhabited by a branch of the Miao ethnic group known as the “Shortskirt” Miao. They number 50,000 to 60,000.Some live in Langdong, Kongshen, and Konglie villages of Rongjiang County, while others may be found living in the Datang area of Leishan County. Their clothing is distinct and colorful for both casual and holiday wear, which consists of a tunic top decorated with silver ornaments and handembroidered designs, and a hand-knitted skirt no more than 20 centimeters long.

  1. Effect of Buffer Bow Structure in Ship-Ship Collision

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Endo, Hisayoshi; Pedersen, Preben Terndrup

    2008-01-01

    A disastrous oil spill from a struck oil tanker has become one of the major problems in view of conservation of maritime environment. So far double hulls (D/H) have been introduced to reduce the consequences of collision and grounding events In order to further reduce the oil spill from struck oi......) and the forward velocity of the struck ship on the collapse mode of the bow of the striking vessel are investigated. Collapse modes, contact forces and energy absorption capabilities of the buffer bows are compared with those of conventional bows....

  2. The sacred weapon: bow and arrow combat in Iran

    OpenAIRE

    Manouchehr Moshtagh Khorasani

    2012-01-01

    The following article presents the development of the bow and arrow, and its important role in the history of Iran. The bow always played an important role not only on the battlefield, but also in hunting. It was also considered as a sacred weapon and additionally a royal symbol. Bow and arrow were considered as a superior weapon in comparison with other types of weapons because one could fight with them at a safer distance as one offered by swords, maces and axes. The first part of the artic...

  3. 滇西腾冲地块东南缘高黎贡山群片麻岩LA-ICP-MS锆石U-Pb年龄及其地质意义%LA-ICP-MS zircon U-Pb age of gneiss from Gaoligong Mountain Group on the southeastern margin of Tengchong block in western Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    林仕良; 丛峰; 高永娟; 邹光富

    2012-01-01

    分布于腾冲地块东南缘的高黎贡山群片麻岩经历了多期变质作用,深熔和糜棱岩化作用表现得十分明显,片麻岩中的锆石具有深熔锆石的特征.在取得的15个锆石年龄数据中,14个数据的206Pb/238U年龄为454.4~546.7Ma,平均年龄为489Ma±16Ma,仅1个数据为261.9Ma.测试结果表明,腾冲地块东南缘的高黎贡山群岩石在早古生代遭受强烈的区域变质作用(包括混合岩化),而这正是泛非事件在腾冲地块上的反映.%Gaoligong gneiss from southeastern Tengchong block has experienced multi-stage metamorphism, and hence shows evident anatexis and mylonitization. 14 of the 15 zircon points yielded **Pb/?[J age of 454.4-546.7Ma, with the average age of 489Ma± 16Ma. The result suggests that the Gaoligong Mountain Group in southeastern Tengchong block underwent intense regional metamorphism including migmatizarion in Early Paleozoic, which reflected the Pan-African event in the Tengchong block.

  4. An approach to predicting bowing control parameter contours in violin performance

    OpenAIRE

    Maestre E.; Ramirez R.

    2010-01-01

    We present a machine learning approach to modeling bowing control parameter contours in violin performance. Using accurate sensing techniques we obtain relevant timbre-related bowing control parameters such as bow transversal velocity, bow pressing force, and bow-bridge distance of each performed note. Each performed note is represented by a curve parameter vector and a number of note classes are defined. The principal components of the data represented by the set of curve p...

  5. Anatomy of wood for bows of string instruments

    OpenAIRE

    Čufar, Katarina; Demšar, Blaž; Zupančič, Martin; Koch, Gerald; Oven, Primož

    2007-01-01

    Four specimens of wood originating from string instrument bows or from the material intended to be used for the repair of bows were obtained from the string instrument workshop "Atelje Demšar". Foreign wood traders supplied the specimens under their commercial names: (1) pernambouc, (2) horse flesh, (3) brasil, and (4) snakewood. Macroscopic and microscopic wood anatomical investigations were carried out in order to verify the nomenclature of the traded specimens. The microscopic identificati...

  6. Dual-Frequency Operation of Bow-Tie Microstrip Antenna

    Institute of Scientific and Technical Information of China (English)

    钟顺时; 张需溥

    2005-01-01

    Characteristics of a single-feed dual-frequency bow-tie microstrip antenna are studied. By using the variation method, simple formulas for resonant frequencies of the bow-tie microstrip antenna are derived. It is shown that the dual-frequency ratio can be controlled easily by choosing the parameters of the antenna. This design gives compact antenna size and simple antenna structure. Experimental results are presented, verifying the validity of the design.

  7. Evolution of bow-tie architectures in biology.

    OpenAIRE

    Tamar Friedlander; Mayo, Avraham E.; Tsvi Tlusty; Uri Alon

    2015-01-01

    Bow-tie or hourglass structure is a common architectural feature found in biological and technological networks. A bow-tie in a multi-layered structure occurs when intermediate layers have much fewer components than the input and output layers. Examples include metabolism where a handful of building blocks mediate between multiple input nutrients and multiple output biomass components, and signaling networks where information from numerous receptor types passes through a small set of signalin...

  8. Bow-shock Pulsar Wind Nebulae Passing Through Density Discontinuities

    CERN Document Server

    Yoon, Doosoo

    2016-01-01

    Bow-shock pulsar wind nebulae are a subset of pulsar wind nebulae that form when the pulsar has high velocity due to the natal kick during the supernova explosion. The interaction between the relativistic wind from the fast-moving pulsar and the interstellar medium produces a bow-shock and a trail, which are detectable in H$_{\\alpha}$ emission. Among such bow-shock pulsar wind nebulae, the Guitar Nebula stands out for its peculiar morphology, which consists of a prominent bow-shock head and a series of bubbles further behind. We present a scenario in which multiple bubbles can be produced when the pulsar encounters a series of density discontinuities in the ISM. We tested the scenario using 2-D and 3-D hydrodynamic simulations. The shape of the guitar nebula can be reproduced if the pulsar traversed a region of declining low density. We also show that if a pulsar encounters an inclined density discontinuity, it produces an asymmetric bow-shock head, consistent with observations of the bow-shock of the millise...

  9. BowTieBuilder: modeling signal transduction pathways

    Directory of Open Access Journals (Sweden)

    Schröder Adrian

    2009-06-01

    Full Text Available Abstract Background Sensory proteins react to changing environmental conditions by transducing signals into the cell. These signals are integrated into core proteins that activate downstream target proteins such as transcription factors (TFs. This structure is referred to as a bow tie, and allows cells to respond appropriately to complex environmental conditions. Understanding this cellular processing of information, from sensory proteins (e.g., cell-surface proteins to target proteins (e.g., TFs is important, yet for many processes the signaling pathways remain unknown. Results Here, we present BowTieBuilder for inferring signal transduction pathways from multiple source and target proteins. Given protein-protein interaction (PPI data signaling pathways are assembled without knowledge of the intermediate signaling proteins while maximizing the overall probability of the pathway. To assess the inference quality, BowTieBuilder and three alternative heuristics are applied to several pathways, and the resulting pathways are compared to reference pathways taken from KEGG. In addition, BowTieBuilder is used to infer a signaling pathway of the innate immune response in humans and a signaling pathway that potentially regulates an underlying gene regulatory network. Conclusion We show that BowTieBuilder, given multiple source and/or target proteins, infers pathways with satisfactory recall and precision rates and detects the core proteins of each pathway.

  10. Numerical simulations of Mach stem formation via intersecting bow shocks

    Science.gov (United States)

    Hansen, E. C.; Frank, A.; Hartigan, P.; Yirak, K.

    2015-12-01

    Hubble Space Telescope observations show bright knots of Hα emission within outflowing young stellar jets. Velocity variations in the flow create secondary bow shocks that may intersect and lead to enhanced emission. When the bow shocks intersect at or above a certain critical angle, a planar shock called a Mach stem is formed. These shocks could produce brighter Hα emission since the incoming flow to the Mach stem is parallel to the shock normal. In this paper we report first results of a study using 2-D numerical simulations designed to explore Mach stem formation at the intersection of bow shocks formed by hypersonic "bullets" or "clumps". Our 2-D simulations show how the bow shock shapes and intersection angles change as the adiabatic index γ changes. We show that the formation or lack of a Mach stem in our simulations is consistent with the steady-state Mach stem formation theory. Our ultimate goal, which is part of an ongoing research effort, is to characterize the physical and observational consequences of bow shock intersections including the formation of Mach stems.

  11. Southeastern Science Policy Colloquium

    Energy Technology Data Exchange (ETDEWEB)

    Humphries, F.

    1995-06-22

    This conference covers four main topics: (1) Southeastern Labor Market and its Impact on Corporate/Industry Development; (2) New Issues for Science and Technology in the Year 2000 and Beyond; (3) The Role of Academia in Developing the Labor Force of the Southeast; and (4) K-12 Education: Challenges for the 21st Century.

  12. Bow and Oblique Shock Formation in Soap Film

    Science.gov (United States)

    Kim, Ildoo; Mandre, Shreyas; Sane, Aakash

    2015-11-01

    In recent years, soap films have been exploited primarily to approximate two-dimensional flows while their three-dimensional character is relatively unattended. An example of the three-dimensional character of the flow in a soap film is the observed Marangoni shock wave when the flow speed exceeds the wave speed. In this study, we investigated the formation of bow and oblique shocks in soap films generated by wedges with different deflection angles. When the wedge deflection angle is small and the film flows fast, oblique shocks are observed. When the oblique shock cannot exists, bow shock is formed upstream the wedge. We characterized the oblique shock angle as a function of the wedge deflection angle and the flow speed, and we also present the criteria for transition between bow and oblique Marangoni shocks in soap films.

  13. Planetary Embryo Bow Shocks as a Mechanism for Chondrule Formation

    CERN Document Server

    Mann, Christopher R; Morris, Melissa M

    2016-01-01

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo's eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adia...

  14. Foreshock ions observed behind the Martian bow shock

    Science.gov (United States)

    Frahm, R. A.; Yamauchi, M.; Winningham, J. D.; Lundin, R.; Sharber, J. R.; Nilsson, H.; Coates, A. J.

    2016-08-01

    The Mars Express Analyzer of Space Plasmas and Energetic Atoms experiment contains ion and electron instruments for conducting plasma measurements. On January 23, 2012, during in-bound travel of Mars Express in the southern hemisphere of Mars from its dawn side toward periapsis at dusk, the plasma instruments measured foreshock-like ion beams extending from outside the bow shock and into the magnetosphere, continuing to a distance of about a proton gyroradius from the bow shock. These ion beams were mostly protons, were observed to have energies greater than solar wind protons, and were not gyrating, in agreement with reflections of the solar wind proton beam. Furthermore, in the foreshock region the ion energy gradually decreased toward the magnetosheath, in agreement with an acceleration by outward-directed electric field in the bowshock. The observations also suggest that this electric field exists even inside the magnetosheath within the distance of a proton gyroradius from the bow shock.

  15. [Forensic medical characteristics of the injuries inflicted by modern sport bow].

    Science.gov (United States)

    Babakhanian, R V; Isakov, V D; Gusev, N Iu; Lebedev, V N

    2006-01-01

    Modern bows are classified as representatives of darts. Construction characteristics of bows and arrows, damage to experimental cotton targets from shooting distance of 1-15 m are described. PMID:16826840

  16. Smashing the Guitar: An Evolving Neutron Star Bow Shock

    OpenAIRE

    S Chatterjee; Cordes, J. M.

    2003-01-01

    The Guitar nebula is a spectacular example of an H-alpha bow shock nebula produced by the interaction of a neutron star with its environment. The radio pulsar B2224+65 is traveling at ~800--1600 km/s (for a distance of 1--2 kpc), placing it on the high-velocity tail of the pulsar velocity distribution. Here we report time evolution in the shape of the Guitar nebula, the first such observations for a bow shock nebula, as seen in H-alpha imaging with the Hubble Space Telescope. The morphology o...

  17. Understanding CANDU fuel bowing in dryout: an industry approach

    International Nuclear Information System (INIS)

    Fuel element bow induced by dryout could potentially perturb the coolant flow distribution and heat transfer from the fuel element to the coolant. Some accident scenarios leading to dryout of the fuel element are: loss of power regulation pump trip, pump seizure, small and large break loss of coolant accidents. In these accidents, it is desirable to show with confidence that the fuel remains sufficiently cooled to maintain its geometry, even if it is in dryout. This can be demonstrated if fuel elements are separated from each other and from the pressure tube, with a sufficient (and stable) gap. Therefore, the prediction of the amount of bow, and its effect on heat transfer conditions is required for the assessments. The utilities have joined force in launching an experimental investigation at Stern Laboratories to characterize the bowing phenomena. This program will investigate the amount of deflection, transient and permanent, that results from accident conditions which cause a dry patch on one side of the sheath. This is expected to bound the consequences of fuel bowing due to dryout. Since the accident transients begin at full power and high coolant pressure (about 10 MPa) they generate sharp thermal gradients (dry patch) and it is necessary to develop a simulation with representative dry fuel sheath conditions initiated from a normal full power and coolant state. The amount of bow is driven by thermal gradients in both the fuel pellets and the sheath, therefore, the thermal gradients should be representative. This program is structured in a series of tests progressing from simple representation to complex simulation. It is divided into 3 experimental phases: Phase 1 - Thermalhydraulic simulation of fuel element bow by a heated tube; Phase 2 - Thermal and mechanical bow with a simulator which accounts for pellet / fuel sheath interaction with internal pellet temperature distributions; and Phase 3 - Fuel element bow with a simulator using Zircaloy-4 fuel sheath

  18. A Multichannel THz Detector Using Integrated Bow-Tie Antennas

    OpenAIRE

    Hairui Liu; Junsheng Yu; Peter Huggard; Byron Alderman

    2013-01-01

    This paper presents a kind of a multichannel THz detector using lens-based bow-tie array. A hyperhemispherical silicon lens is employed to provide a focal plane; 8 bow-tie elements are arranged on the focal plane with careful design to show a performance of broadband, high gain, well compact, and easy assembling. These characteristics of the detector are preferred for detecting weak THz signal. Measured far field shows that the radiation pattern of each element is shifted angularly, by ≈9°, w...

  19. Crushing of ship bows in head-on collision

    DEFF Research Database (Denmark)

    Ocakli, H.; Zhang, S.; Pedersen, Preben Terndrup

    2004-01-01

    Semi-analytical methods for analysis of plate crushing and ship bow damage in head-on collisions are developed in this paper. Existing experimental and theoretical studies for crushing analysis of plated structures are summarized and compared. Simple formulae for determining the crushing force...... approach developed can be used easily to determine the crushing resistance and damage extent of the ship bow when ship length and collision speed are known. The method can be used in probabilistic analysis of damage extents in ship collisions where a large number of calculations are generally required....

  20. Multispacecraft observations of the terrestrial bow shock and magnetopause during extreme solar wind disturbances

    DEFF Research Database (Denmark)

    Tatrallyay, M.; Erdos, G.; Nemeth, Z.;

    2012-01-01

    by the Cluster spacecraft were best predicted by the 3-D model of Lin et al. (2010). The applied empirical bow shock models and the 3-D semi-empiric bow shock model combined with magnetohydrodynamic (MHD) solution proved to be insufficient for predicting the observed unusual bow shock locations during large...

  1. 77 FR 19661 - City of Broken Bow, OK; Notice of Technical Conference

    Science.gov (United States)

    2012-04-02

    ... Energy Regulatory Commission City of Broken Bow, OK; Notice of Technical Conference March 21, 2012. Take.... Forest Service on November 16, 2007 for the Broken Bow Re-Regulation Dam Hydroelectric Project No. 12470.... Forest Service's Hochatown Office, Route 4, Broken Bow, OK 74728. All local, state, and federal...

  2. Ion acoustic stability analysis of the earth's bow shock

    Science.gov (United States)

    Greenstadt, E. W.; Scarf, F. L.; Formisano, V.; Russell, C. T.; Neugebauer, M.

    1978-01-01

    A marginal stability criterion for ion acoustic waves is applied to the analysis of five thin bow shock crossings observed by OGO-5; the observations began with the satellite in the magnetosheath. The assumption of marginally stable ion acoustic wave generation in the shock ramp provides the basis for determining the thickness of the magnetic gradients for subcritical, quasi-perpendicular shock features.

  3. Application of Bow-tie methodology to improve patient safety.

    Science.gov (United States)

    Abdi, Zhaleh; Ravaghi, Hamid; Abbasi, Mohsen; Delgoshaei, Bahram; Esfandiari, Somayeh

    2016-05-01

    Purpose - The purpose of this paper is to apply Bow-tie methodology, a proactive risk assessment technique based on systemic approach, for prospective analysis of the risks threatening patient safety in intensive care unit (ICU). Design/methodology/approach - Bow-tie methodology was used to manage clinical risks threatening patient safety by a multidisciplinary team in the ICU. The Bow-tie analysis was conducted on incidents related to high-alert medications, ventilator associated pneumonia, catheter-related blood stream infection, urinary tract infection, and unwanted extubation. Findings - In total, 48 potential adverse events were analysed. The causal factors were identified and classified into relevant categories. The number and effectiveness of existing preventive and protective barriers were examined for each potential adverse event. The adverse events were evaluated according to the risk criteria and a set of interventions were proposed with the aim of improving the existing barriers or implementing new barriers. A number of recommendations were implemented in the ICU, while considering their feasibility. Originality/value - The application of Bow-tie methodology led to practical recommendations to eliminate or control the hazards identified. It also contributed to better understanding of hazard prevention and protection required for safe operations in clinical settings. PMID:27142951

  4. Hierarchical modularity of nested bow-ties in metabolic networks

    Directory of Open Access Journals (Sweden)

    Luo Jian-Hua

    2006-08-01

    Full Text Available Abstract Background The exploration of the structural topology and the organizing principles of genome-based large-scale metabolic networks is essential for studying possible relations between structure and functionality of metabolic networks. Topological analysis of graph models has often been applied to study the structural characteristics of complex metabolic networks. Results In this work, metabolic networks of 75 organisms were investigated from a topological point of view. Network decomposition of three microbes (Escherichia coli, Aeropyrum pernix and Saccharomyces cerevisiae shows that almost all of the sub-networks exhibit a highly modularized bow-tie topological pattern similar to that of the global metabolic networks. Moreover, these small bow-ties are hierarchically nested into larger ones and collectively integrated into a large metabolic network, and important features of this modularity are not observed in the random shuffled network. In addition, such a bow-tie pattern appears to be present in certain chemically isolated functional modules and spatially separated modules including carbohydrate metabolism, cytosol and mitochondrion respectively. Conclusion The highly modularized bow-tie pattern is present at different levels and scales, and in different chemical and spatial modules of metabolic networks, which is likely the result of the evolutionary process rather than a random accident. Identification and analysis of such a pattern is helpful for understanding the design principles and facilitate the modelling of metabolic networks.

  5. Numerical Simulations of Mach Stem Formation via Intersecting Bow Shocks

    CERN Document Server

    Hansen, Edward C; Hartigan, Patrick

    2014-01-01

    Hubble Space Telescope observations show bright knots of H$\\alpha$ emission within outflowing young stellar jets. Velocity variations in the flow create secondary bow shocks that may intersect and lead to enhanced emission. When the bow shocks intersect at or above a certain critical angle, a planar shock called a Mach stem is formed. These shocks could produce brighter H$\\alpha$ emission since the incoming flow to the Mach stem is parallel to the shock normal. In this paper we report first results of a study using 2-D numerical simulations designed to explore Mach stem formation at the intersection of bow shocks formed by hypersonic "bullets" or "clumps". Our 2-D simulations show how the bow shock shapes and intersection angles change as the adiabatic index $\\gamma$ changes. We show that the formation or lack of a Mach stem in our simulations is consistent with the steady-state Mach stem formation theory. Our ultimate goal, which is part of an ongoing research effort, is to characterize the physical and obse...

  6. THE JET-DRIVEN BOW SHOCK IN OUTFLOWS

    Institute of Scientific and Technical Information of China (English)

    ZhangQing; ZhengXingwu

    1999-01-01

    Recent high resolution observations show the high collimated bipolar molecular outflows from young stellar objects, such as NGC 2 264G and NGC 2 024. Existing models can not yet give complete interpretations of the structure and properties of the observed flow. Here, we propose a jet-driven bow

  7. Modeling non-thermal emission from stellar bow shocks

    CERN Document Server

    Pereira, V; Miceli, M; Bonito, R; de Castro, E

    2016-01-01

    Runaway O- and early B-type stars passing throughout the interstellar medium at supersonic velocities and characterized by strong stellar winds may produce bow shocks that can serve as particle acceleration sites. Previous theoretical models predict the production of high energy photons by non-thermal radiative processes, but their efficiency is still debated. We aim to test and explain the possibility of emission from the bow shocks formed by runaway stars traveling through the interstellar medium by using previous theoretical models. We apply our model to AE Aurigae, the first reported star with an X-ray detected bow shock, to BD+43 3654, in which the observations failed in detecting high energy emission, and to the transition phase of a supergiant star in the late stages of its life.From our analysis, we confirm that the X-ray emission from the bow shock produced by AE Aurigae can be explained by inverse Compton processes involving the infrared photons of the heated dust. We also predict low high energy fl...

  8. Fatigue analysis of the bow structure of FPSO

    Institute of Scientific and Technical Information of China (English)

    HU Zhi-qiang; GAO Zhen; GU Yong-ning

    2003-01-01

    The bow structure of FPSO moored by the single mooring system is rather complicated. There are many potential hot spots in connection parts of structures between the mooring support frame and the forecastle. Mooring forces, which are induced by wave excitation and transferred by the YOKE and the mooring support frame, may cause fatigue damage to the bow structure. Different from direct wave-induced-forces, the mooring force consists of wave frequency force (WF) and 2nd draft low frequency force (LF)[3], which are represented by two sets of short-term distribution respectively. Based on two sets of short-term distribution of mooring forces obtained by the model test, the fatigue damage of the bow structure of FPSO is analyzed, with emphasis on two points. One is the procedure and position selection for fatigue check, and the other is the application of new formulae for the calculation of accumulative fatigue damage caused by two sets of short-term distribution of hot spot stress range. From the results distinguished features of fatigue damage to the FPSO's bow structure can be observed.

  9. Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas: Chapter B in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming

    Science.gov (United States)

    Vikre, Peter G.; Benson, Mary Ellen; Bleiwas, Donald I.; Colgan, Joseph P.; Cossette, Pamela M.; DeAngelo, Jacob; Dicken, Connie L.; Drake, Ronald M.; du Bray, Edward A.; Fernette, Gregory L.; Glen, Jonathan M.G.; Haacke, Jon E.; Hall, Susan M.; Hofstra, Albert H.; John, David A.; Ludington, Stephen; Mihalasky, Mark J.; Rytuba, James J.; Shaffer, Brian N.; Stillings, Lisa L.; Wallis, John C.; Williams, Colin F.; Yager, Douglas B.; Zürcher, Lukas

    2016-10-04

    This report is temporarily unavailableSummaryThe U.S. Department of the Interior has proposed to withdraw approximately 10 million acres of Federal lands from mineral entry (subject to valid existing rights) from 12 million acres of lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming (for further discussion on the lands involved see Scientific Investigations Report 2016–5089–A). The purpose of the proposed action is to protect the greater sage-grouse (Centrocercus urophasianus) and its habitat from potential adverse effects of locatable mineral exploration and mining. The U.S. Geological Survey Sagebrush Mineral-Resource Assessment (SaMiRA) project was initiated in November 2015 and supported by the Bureau of Land Management to (1) assess locatable mineral-resource potential and (2) to describe leasable and salable mineral resources for the seven SFAs and Nevada additions.This chapter summarizes the current status of locatable, leasable, and salable mineral commodities and assesses the potential of selected locatable minerals in lands proposed for withdrawal that span the Nevada, Oregon, Idaho, and Utah borders. In this report, the four study areas evaluated were (1) the Sheldon-Hart Mountain National Wildlife Refuge Complex SFA in Washoe County, Nevada, and Harney and Lake Counties, Oregon; (2) the Southeastern Oregon and North-Central Nevada SFA in Humboldt County, Nevada, and Harney and Malheur Counties, Oregon; (3) the Southern Idaho and Northern Nevada SFA in Cassia, Owyhee, and Twin Falls Counties, Idaho, Elko County, Nevada, and Box Elder County, Utah; and (4) the Nevada additions in Humboldt and Elko Counties, Nevada.

  10. Study on Development and Realization Path of Smart Medical Logistics System of Southeastern Mountainous Regions in Jilin%吉林省东南部山区智能医药物流建设研究及实践路径

    Institute of Scientific and Technical Information of China (English)

    葛金辉; 王洪珍; 张仁忠

    2014-01-01

    In this paper, in view of the problems of the medical logistics system of the southeastern mountainous regions in Jilin, on the basis of a discussion of the characteristics of medical logistics processes, we studied the measures to integrate the medical enterprises, improve their brand value and optimize their resources and at the end proposed to build the smart medical logistics system and integrate the green logistics and supply chain mode into the development of the medical logistics system of these regions.%针对吉林省东南部山区医药物流集散度较低、企业管理模式陈旧、医药物流管理比较粗放等情况,在探讨了医药物流特征的基础上,研究了智能医药物流的特征,并提出整合医药企业、提升品牌,优化企业资源,构建完善的医药物流管理系统,培养一批专业化的物流管理和技术人才,建设专业化的医药物流服务商,强化绿色物流理念,构建绿色物流供应链及将智能医药物流与医药电子商务有机融合的发展模式等实践路径。

  11. Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas: Chapter B in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming

    Science.gov (United States)

    Vikre, Peter G.; Benson, Mary Ellen; Bleiwas, Donald I.; Colgan, Joseph P.; Cossette, Pamela M.; DeAngelo, Jacob; Dicken, Connie L.; Drake, Ronald M.; du Bray, Edward A.; Fernette, Gregory L.; Glen, Jonathan M.G.; Haacke, Jon E.; Hall, Susan M.; Hofstra, Albert H.; John, David A.; Ludington, Stephen; Mihalasky, Mark J.; Rytuba, James J.; Shaffer, Brian N.; Stillings, Lisa L.; Wallis, John C.; Williams, Colin F.; Yager, Douglas B.; Zürcher, Lukas

    2016-10-04

    SummaryThe U.S. Department of the Interior has proposed to withdraw approximately 10 million acres of Federal lands from mineral entry (subject to valid existing rights) from 12 million acres of lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming (for further discussion on the lands involved see Scientific Investigations Report 2016–5089–A). The purpose of the proposed action is to protect the greater sage-grouse (Centrocercus urophasianus) and its habitat from potential adverse effects of locatable mineral exploration and mining. The U.S. Geological Survey Sagebrush Mineral-Resource Assessment (SaMiRA) project was initiated in November 2015 and supported by the Bureau of Land Management to (1) assess locatable mineral-resource potential and (2) to describe leasable and salable mineral resources for the seven SFAs and Nevada additions.This chapter summarizes the current status of locatable, leasable, and salable mineral commodities and assesses the potential of selected locatable minerals in lands proposed for withdrawal that span the Nevada, Oregon, Idaho, and Utah borders. In this report, the four study areas evaluated were (1) the Sheldon-Hart Mountain National Wildlife Refuge Complex SFA in Washoe County, Nevada, and Harney and Lake Counties, Oregon; (2) the Southeastern Oregon and North-Central Nevada SFA in Humboldt County, Nevada, and Harney and Malheur Counties, Oregon; (3) the Southern Idaho and Northern Nevada SFA in Cassia, Owyhee, and Twin Falls Counties, Idaho, Elko County, Nevada, and Box Elder County, Utah; and (4) the Nevada additions in Humboldt and Elko Counties, Nevada.

  12. Double tibial osteotomy for bow leg patients: A case series

    Directory of Open Access Journals (Sweden)

    Khalilollah Nazem

    2013-01-01

    Full Text Available Background: High tibia osteotomy (HTO is a common surgical operation for correction of genu varum deformity. In some patients, there are concurrent tibia vara and genu varum (bow leg. This study aimed to consider the possibility of better correction of bow leg deformity after double level tibial osteotomy (DLTO. Materials and Methods: A case series of 10 patients of genu varum in addition to tibia vara (bow leg deformity who were referred to orthopedic ward of an academic hospital of Isfahan- Iran during 2009-2011 were included in the study. The mean age was 17.3 ± 3.1 years and all of them underwent DLTO. The results of treatment have been assessed based on clinical and radiological parameters before and after surgery. Results: The mean pre- and post operative values for Tibia-Femoral Angle, Medial Proximal of Tibia Angle (MPTA, and Lateral Distal of Tibia Angle (LDTA were 18.13 ± 3.05° vs. 3.93 ± 0.66°, 79.13 ± 3.4° vs. 89.7 ± 1.8° and 96.40 ± 1.8° vs. 88.73 ± 3.0° respectively (P < 0.05. Improvement of all radiological parameters was meaningful. Seventy three percent of patients had normal mechanical axis of limb after surgery. The remaining cases had varus deformity in distal femur that was corrected by valgus supracondylar osteotomy in an additional operation. Limited range of motion (ROM near knee and ankle was not observed. Conclusion : DLTO correct bow leg deformity in the point of alignment of limb and paralleling of knee and ankle joint more effectively. This method can be used in metabolic and congenital bow leg which deformities are present in throughout of the lower limb. We described this technique for the first time.

  13. Reconnaissance geology and geochronology of the Precambrian of the Granite Mountains, Wyoming

    Science.gov (United States)

    Peterman, Zell E.; Hildreth, Robert A.

    1978-01-01

    The Precambrian of the western part of the Granite Mountains, Wyoming, contains a metamorphic complex of gneisses, schists, and amphibolites that were derived through amphibolite-grade metamorphism from a sedimentary-volcanic sequence perhaps similar to that exposed in the southeastern Wind River Mountains. Whole-rock Rb-Sr dating places the time of metamorphism at 2,860?80 million years. A high initial 87Sr/ 86 S r ratio of 0.7048 suggests that either the protoliths or the source terrane of the sedimentary component is several hundred million years older than the time of metamorphism. Following an interval of 300:t100 million years for which the geologic record is lacking or still undeciphered, the metamorphic complex was intruded by a batholith and satellite bodies of medium- to coarse-grained, generally massive biotite granite and related pegmatite and aplite. The main body of granite is dated at 2,550?60 million years by the Rb-Sr method. Limited data suggest that diabase dikes were emplaced and nephrite veins were formed only shortly after intrusion of the granite. Emplacement of the granite at about 2,550 million years ago appears to be related to a major period of regional granitic plutonism in the Precambrian of southern and western Wyoming. Granites, in the strict sense, that are dated between 2,450 and 2,600 million years occur in the Teton Range, the Sierra Madre, the Medicine Bow Mountains and the Laramie Range. This episode of granitic plutonism occured some 50 to 100 million years later than the major tonalitic to granitic plutonism in the Superior province of northern Minnesota and adjacent Ontario-the nearest exposed Precambrian W terrane that is analogous to the Wyoming province. Initial 87Sr / 86Sr ratios of some of the Wyoming granites are higher than expected if the rocks had been derived from juvenile magmas and it is likely that older crustal rocks were involved to some degree in the generation of these granites. Slightly to highly disturbed

  14. A Multichannel THz Detector Using Integrated Bow-Tie Antennas

    Directory of Open Access Journals (Sweden)

    Hairui Liu

    2013-01-01

    Full Text Available This paper presents a kind of a multichannel THz detector using lens-based bow-tie array. A hyperhemispherical silicon lens is employed to provide a focal plane; 8 bow-tie elements are arranged on the focal plane with careful design to show a performance of broadband, high gain, well compact, and easy assembling. These characteristics of the detector are preferred for detecting weak THz signal. Measured far field shows that the radiation pattern of each element is shifted angularly, by ≈9°, which can be used for THz imaging. Tested responsivity of the detector shows a good spectral performance from 260 to 400 GHz: respective values were ≥220 V/W, and the best NEP is achieved at about 60 pW/. Besides that, the proposed antenna has advantages of simple structure, easy fabrication, and low cost.

  15. Breaking the BOWS Watermarking System: Key Guessing and Sensitivity Attacks

    Directory of Open Access Journals (Sweden)

    Comesaña Pedro

    2007-01-01

    Full Text Available From December 15, 2005 to June 15, 2006, the watermarking community was challenged to remove the watermark from 3 different 512×512 watermarked images while maximizing the peak signal-to-noise ratio (PSNR measured by comparing the watermarked signals with their attacked counterparts. This challenge, which bore the inviting name of Break Our Watermarking System (BOWS, had as its main objective to enlarge the current knowledge on attacks to watermarking systems. In this paper, the main results obtained by the authors when attacking the BOWS system are presented and compared with strategies followed by other groups. Essentially, two different approaches have been followed: exhaustive search of the secret key and blind sensitivity attacks.

  16. Cluster Close Separation at the Bow Shock Campaign: Initial Results.

    Science.gov (United States)

    Balikhin, M. A.; Sagdeev, R.; Walker, S. N.; Malkov, M.; Krasnoselskikh, V.; Khotyaintsev, Y. V.; Fazakerley, A. N.; Doss, N.

    2015-12-01

    The Cluster close separation at the terrestrial bow shock campaign was aimed at probing the terrestrial bow shock front using multi-scale spacecraft separations. The closest separation (structure of the magnetic ramp. It is shown that the magnetic field perturbations observed within the ramp along the shock normal possess spatial scales a few times shorter than the ramp region itself, and are accompanied by variations in the electric field with magnitudes of a few tens mV/m. Using dual spacecraft measurements enables us to show that in the plane of the shock front the characteristic width of these structures corresponds to electron scales. Comparison of the magnetic field profile obtained from Cluster 3 and 4 indicates possibility that the initial stage of the front reformation is observed. However alternative explanations ( kinetic instabilities, corrugation instability) are also discussed.

  17. Mass-loading of bow shock pulsar wind nebulae

    CERN Document Server

    Morlino, G; Vorster, M J

    2015-01-01

    We investigate the dynamics of bow shock nebulae created by pulsars moving supersonically through a partially ionized interstellar. A fraction of interstellar neutrals penetrating into the tail region of a pulsar wind will undergo photo-ionization due to the UV light emitted by the nebula, with the resulting mass loading dramatically changing the flow dynamics of the light leptonic pulsar wind. Using a quasi 1-D hydrodynamic model of both non-relativistic and relativistic flow, and focusing on scales much larger than the stand-off distance, we find that a relatively small density of neutrals, as low as $n_{\\rm ISM}=10^{-4}\\,\\text{cm}^{-3}$, is sufficient to strongly affect the tail flow. Mass loading leads to the fast expansion of the pulsar wind tail, making the tail flow intrinsically non-stationary. The shapes predicted for the bow shock nebulae compare well with observations, both in H$\\alpha$ and X-rays.

  18. Face bow and articulator for planning orthognathic surgery: 2 articulator.

    Science.gov (United States)

    Walker, Fraser; Ayoub, Ashraf F; Moos, Khursheed F; Barbenel, Joseph

    2008-10-01

    Patients who require orthognathic surgery may have asymmetry of the position of the temporomandibular joints relative to the maxilla, which is impossible to reproduce on the current semiadjustable articulators used for surgical planning. We describe a highly-adjustable spirit level orthognathic face bow that allows records to be made of patients with asymmetrical maxillae. The orthognathic articulator also allows the position of the condylar components of the articulator to be adjusted in three dimensions. The use of the new face bow and articulator made it possible to mount the dental casts of asymmetrical faces to reproduce their clinical appearance. The devices were evaluated by comparing the measurements of anatomical variables obtained from cephalometric radiographs with equivalent values obtained from the orthognathic articulator and casts mounted on the articulator. Although the measurements showed significant intersubject variability, the angle between the horizontal and maxillary occlusal plane, occlusal cant angle, and intercondylar widths, were not significantly different.

  19. Mass-loading of bow shock pulsar wind nebulae

    CERN Document Server

    Morlino, G; Vorster, M

    2016-01-01

    We investigate the dynamics of bow shock nebulae created by pulsars moving supersonically through a partially ionized interstellar medium. A fraction of interstellar neutral hydrogen atoms penetrating into the tail region of a pulsar wind will undergo photo-ionization due to the UV light emitted by the nebula, with the resulting mass loading dramatically changing the flow dynamics of the light leptonic pulsar wind. Using a quasi 1-D hydrodynamic model of relativistic flow we find that if a relatively small density of neutral hydrogen, as low as $10^{-4}$ cm$^{-3}$, penetrate inside the pulsar wind, this is sufficient to strongly affect the tail flow. Mass loading leads to the fast expansion of the pulsar wind tail, making the tail flow intrinsically non-stationary. The shapes predicted for the bow shock nebulae compare well with observations, both in H$\\alpha$ and X-rays.

  20. Arctic Bowyery – the Use of Compression Wood in Bows in the Subarctic and Arctic Regions of Eurasia and America

    Directory of Open Access Journals (Sweden)

    Marcus Lepola

    2015-06-01

    Full Text Available This paper is a study of the traditional use of a special kind of wood in bow construction in Eurasia and North America. This special kind of wood, called compression wood and coming from coniferous trees, has unique qualities that makes it suitable for bow construction. Bows made using this special wood have been referred to as Finno-Ugric bows, Sámi bows, Two-Wood bows and Eurasia laminated bows. These bows appear to have developed from archaic forms of compression wood self bows that were made from a single piece of wood. Recently features similar to the Eurasian compression wood bows have been discovered in bows originating from Alaska, and the use of compression wood for bow manufacture has been known to some Canadian Inuit groups. This paper addresses the origin and possible diffusion pattern of this innovation in bow technology in Eurasia and suggests a timeframe and a possible source for the transfer of this knowledge to North America. This paper also discusses the role of the Asiatic composite bow in the development of bows in Eurasia.

  1. Organizing learning processes on risks by using the bow-tie representation.

    Science.gov (United States)

    Chevreau, F R; Wybo, J L; Cauchois, D

    2006-03-31

    The Aramis method proposes a complete and efficient way to manage risk analysis by using the bow-tie representation. This paper shows how the bow-tie representation can also be appropriate for experience learning. It describes how a pharmaceutical production plant uses bow-ties for incident and accident analysis. Two levels of bow-ties are constructed: standard bow-ties concern generic risks of the plant whereas local bow-ties represent accident scenarios specific to each workplace. When incidents or accidents are analyzed, knowledge that is gained is added to existing local bow-ties. Regularly, local bow-ties that have been updated are compared to standard bow-ties in order to revise them. Knowledge on safety at the global and at local levels is hence as accurate as possible and memorized in a real time framework. As it relies on the communication between safety experts and local operators, this use of the bow-ties contributes therefore to organizational learning for safety. PMID:16125315

  2. Statistical modeling of bowing control applied to violin sound synthesis

    OpenAIRE

    Maestre E.; Blaauw M.; Bonada J.; Guaus E.; Perez A.

    2010-01-01

    Excitation-continuous music instrument control patterns are often not explicitly represented in current sound synthesis techniques when applied to automatic performance. Both physical model-based and sample-based synthesis paradigms would benefit from a flexible and accurate instrument control model, enabling the improvement of naturalness and realism. We present a framework for modeling bowing control parameters in violin performance. Nearly non-intrusive sensing techniques allow fo...

  3. BowTieBuilder: modeling signal transduction pathways

    OpenAIRE

    Schröder Adrian; Dräger Andreas; Planatscher Hannes; Spangenberg Lucía; Supper Jochen; Zell Andreas

    2009-01-01

    Abstract Background Sensory proteins react to changing environmental conditions by transducing signals into the cell. These signals are integrated into core proteins that activate downstream target proteins such as transcription factors (TFs). This structure is referred to as a bow tie, and allows cells to respond appropriately to complex environmental conditions. Understanding this cellular processing of information, from sensory proteins (e.g., cell-surface proteins) to target proteins (e.g...

  4. Performance Characterization of Radial Stub Microstrip Bow-Tie Antenna

    OpenAIRE

    B.T.P.Madhav; S.S. Mohan Reddy; Neha Sharma; J. Ravindranath Chowdary; Bala Rama Pavithra; K.N.V.S. Kishore; G Sriram; B. Sachin Kumar

    2013-01-01

    In this paper a novel radial stub feeding microstrip bow-tie antenna is designed to operate between C and X band and its performance characterization is presented. This antenna is having simple structure and topology over other stub loaded antennas. In addition the proposed antenna adjusts to the desired frequency easily. Antenna output parameters like radiation pattern, axial ratio, directive gain andquality factor are simulated and presented in this current work.

  5. Performance Characterization of Radial Stub Microstrip Bow-Tie Antenna

    Directory of Open Access Journals (Sweden)

    B.T.P.Madhav

    2013-04-01

    Full Text Available In this paper a novel radial stub feeding microstrip bow-tie antenna is designed to operate between C and X band and its performance characterization is presented. This antenna is having simple structure and topology over other stub loaded antennas. In addition the proposed antenna adjusts to the desired frequency easily. Antenna output parameters like radiation pattern, axial ratio, directive gain andquality factor are simulated and presented in this current work.

  6. Broadband bow-tie antenna with tapered balun

    OpenAIRE

    Jaafar, Hussein Mohammed

    2014-01-01

    ABSTRACT: In microwave applications spectrum Industrial, Scientific and Medical (ISM) band, especially in wireless communication systems applications such as GSM, 3G, Wi-Fi and Wi-MAX applications, high antenna characteristics such as high gain and wide bandwidth are required. In this thesis, a broadband Bow Tie Antenna (BTA) with high performance characteristics has been designed, to cover the wireless application requirements. One of the fundamental problems of the transmission line in the ...

  7. Planetary Embryo Bow Shocks as a Mechanism for Chondrule Formation

    OpenAIRE

    Mann, Christopher R.; Boley, Aaron C.; Morris, Melissa M.

    2016-01-01

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo's eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting t...

  8. Polarization of circumstellar bow shocks due to electron scattering

    Science.gov (United States)

    Shrestha, Manisha; Hoffman, J. L.; Neilson, H.; Ignace, R.

    2014-01-01

    Circumstellar material (CSM) provides a link between interacting supernovae and their massive progenitor stars. This CSM arises from stellar winds, outflows, or eruptions from a massive star before it explodes and can be detected around stars or supernovae with polarimetric observations. We use a Monte Carlo based radiative transfer code (SLIP) to investigate the polarization created by different models for the CSM surrounding a central source such as supernovae or massive stars. We vary parameters such as the shape, optical depth, temperature, and brightness of the CSM and compare the simulated flux and polarization behavior with observational data. We present results from new simulations that assume a bow shock shape for the CSM. Bow shocks are commonly observed around massive stars; this shape forms when a star moving more quickly than the speed of sound in the local interstellar medium emits a stellar wind that drives a shock wave into the ISM. Since a bow shock projects an aspherical shape onto the sky, light from the central source that scatters in the shock region becomes polarized. We present electron-scattering polarization maps for this geometry and discuss the behavior of observed polarization with viewing angle in the unresolved case.

  9. A Survey for H$\\alpha$ Pulsar Bow Shocks

    CERN Document Server

    Brownsberger, Sasha

    2014-01-01

    We report on a survey for H$\\alpha$ bow shock emission around nearby $\\gamma$-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around {\\it Fermi} pulsar PSR J1741$-$2054, we now report H$\\alpha$ structures around two additional $\\gamma$-ray pulsars, PSR J2030+4415 and PSR J1509$-$5850. These are the first known examples of H$\\alpha$ nebulae with pre-ionization halos. With new measurements, we show that a simple analytic model can account for the angular size and flux of the bow shocks' apices. The latter, in particular, provides a new pulsar probe and indicates large moments of inertia and smaller distances than previously assumed, in several cases. In particular we show that the re-measured PSR J0437$-$4715 shock flux implies $I = (1.7\\pm 0.2) \\times 10^{45}/(f_{HI} {\\rm sin}i) {\\rm g\\,cm^2}$. We also derive a distance $d\\approx 0.72$kpc for the $\\gamma$-ray only pulsar PSR J2030+4415 and revised dis...

  10. PLANETARY EMBRYO BOW SHOCKS AS A MECHANISM FOR CHONDRULE FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Christopher R.; Boley, Aaron C. [Department of Physics and Astronomy University of British Columbia Vancouver, BC V6T 1Z1 (Canada); Morris, Melissa A. [Physics Department State University of New York at Cortland Cortland, NY 13045 (United States)

    2016-02-20

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo’s eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adiabatic and radiative conditions, with multiple treatments for the local opacities. Shock speeds of 5, 6, and 7 km s{sup −1} are explored. We find that a high-mass atmosphere and inefficient radiative conditions can produce peak temperatures and cooling rates that are consistent with the constraints set by chondrule furnace studies. For most conditions, the derived cooling rates are potentially too high to be consistent with chondrule formation.

  11. Planetary Embryo Bow Shocks as a Mechanism for Chondrule Formation

    Science.gov (United States)

    Mann, Christopher R.; Boley, Aaron C.; Morris, Melissa A.

    2016-02-01

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo’s eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adiabatic and radiative conditions, with multiple treatments for the local opacities. Shock speeds of 5, 6, and 7 km s-1 are explored. We find that a high-mass atmosphere and inefficient radiative conditions can produce peak temperatures and cooling rates that are consistent with the constraints set by chondrule furnace studies. For most conditions, the derived cooling rates are potentially too high to be consistent with chondrule formation.

  12. Mountain research

    Science.gov (United States)

    The newly incorporated International Mountain Society (IMS) will in May begin publication of an interdisciplinary scientific journal, Mountain Research and Development. The quarterly will be copublished with the United National University; additional support will come from UNESCO.A primary objective of IMS is to ‘help solve mountain land-use problems by developing a foundation of scientific and technical knowledge on which to base management decisions,’ according to Jack D. Ives, president of the Boulder-based organization. ‘The Society is strongly committed to the belief that a rational worldwide approach to mountain problems must involve a wide range of disciplines in the natural and human sciences, medicine, architecture, engineering, and technology.’

  13. Sinogram bow-tie filtering in FBP PET reconstruction.

    Science.gov (United States)

    Abella, M; Vaquero, J J; Soto-Montenegro, M L; Lage, E; Desco, M

    2009-05-01

    Low-pass filtering of sinograms in the radial direction is the most common practice to limit noise amplification in filtered back projection (FBP) reconstruction of positron emission tomography studies. Other filtering strategies have been proposed to prevent the loss in resolution due to low-pass radial filters, although results have been diverse. Using the well-known properties of the Fourier transform of a sinogram, the authors defined a binary mask that matches the expected shape of the support region in the Fourier domain of the sinogram ("bow tie"). This mask was smoothed by a convolution with a ten-point Gaussian kernel which not only avoids ringing but also introduces a pre-emphasis at low frequencies. A new filtering scheme for FBP is proposed, comprising this smoothed bow-tie filter combined with a standard radial filter and an axial filter. The authors compared the performance of the bow-tie filtering scheme with that of other previously reported methods: Standard radial filtering, angular filtering, and stackgram-domain filtering. All the quantitative data in the comparisons refer to a baseline reconstruction using a ramp filter only. When using the smallest size of the Gaussian kernel in the stackgram domain, the authors achieved a noise reduction of 33% at the cost of degrading radial and tangential resolutions (14.5% and 16%, respectively, for cubic interpolation). To reduce the noise by 30%, the angular filter produced a larger degradation of contrast (3%) and tangential resolution (46% at 10 mm from the center of the field of view) and showed noticeable artifacts in the form of circular blurring dependent on the distance to the center of the field of view. For a similar noise reduction (33%), the proposed bow-tie filtering scheme yielded optimum results in resolution (gain in radial resolution of 10%) and contrast (1% increase) when compared with any of the other filters alone. Experiments with rodent images showed noticeable image quality

  14. Dependence of sound characteristics on the bowing position in a violin

    Science.gov (United States)

    Roh, YuJi; Kim, Young H.

    2014-12-01

    A quantitative analysis of violin sounds produced for different bowing positions over the full length of a violin string has been carried out. An automated bowing machine was employed in order to keep the bowing parameters constant. A 3-dimensional profile of the frequency spectrum was introduced in order to characterize the violin's sound. We found that the fundamental frequency did not change for different bowing positions, whereas the frequencies of the higher harmonics were different. Bowing the string at 30 mm from the bridge produced musical sounds. The middle of the string was confirmed to be a dead zone, as reported in previous works. In addition, the quarter position was also found to be a dead zone. Bowing the string 90 mm from the bridge dominantly produces a fundamental frequency of 864 Hz and its harmonics.

  15. Asymmetries in the location of the Venus and Mars bow shock

    International Nuclear Information System (INIS)

    An examination of observations of the position of the terminator bow shock at Venus and Mars shows that the terminator bow shock varies with the angle between the local bow shock normal and the upstream magnetic field, θBN. The part of the shock on the quasi-parallel side is closer to the planet than the part on the quasi-perpendicular side, a result which had been sggested by an earlier computer simulation by Thomas and Winske [1990]. This bow shock asymmetry is observed to be larger at Mars than at Venus

  16. Interaction between an interplanetary magnetic cloud and the Earth's magnetosphere: Motions of the bow shock

    Science.gov (United States)

    Wu, D. J.; Chao, J. K.; Lepping, R. P.

    2000-06-01

    An interplanetary magnetic cloud (IMC) is an important solar-terrestrial connection event. It is an ideal object for the study of solar-terrestrial relations and space weather because the Earth's space environment can be affected considerably during an IMC passage. An IMC was observed to pass the Earth during October 18-20, 1995. Wind recorded its interplanetary characteristics at ~175RE upstream of the Earth's bow shock, and ~45 min later, Geotail, being near the nominal location of the dawn bow shock, detected IMC-related multiple bow shock crossings. Using simultaneous measurements from Wind and Geotail, we analyzed, with a semiempirical bow shock model with two parameters, the bow shock motion caused by the interaction of the IMC with the magnetosphere during the passage. We also compared the bow shock motion predicted by the model, and hence the predicted Geotail bow shock crossings, with Geotail observations of the actual crossings. The results showed that the observed multiple bow shock crossings, which were obviously due to temporal variations of the upstream solar wind, can be well explained by the model-predicted bow shock motion.

  17. Southeastern Coastal Plain aquifer system

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Southeastern Coastal Plain aquifer system in Kentucky, Tennessee, Mississippi, Alabama, Georgia, and South Carolina.

  18. Successful Female Mountaineers

    Institute of Scientific and Technical Information of China (English)

    TANSIYIN

    2004-01-01

    The Third Mountaineering Meet took place from September 26 to October 8, 2003. It was sponsored by the Tibet Association for Mountaineers and undertaken by the Tibet Mountaineering Team and the Tibet Mountaineering School.

  19. Tibial bowing in children - what is normal? A radiographic study

    International Nuclear Information System (INIS)

    To define osseous landmarks on tibia radiographs in order to establish age-related normal values characterizing physiological tibial bowing in children. Five hundred and twenty-six patients aged 0-17 years with normal radiographs of the lower legs were identified and retrospectively reviewed by two blinded radiologists. In anteroposterior (ap)/lateral (lat)-views, 3 lines defined tibial length and angulation. Line-A connecting proximal to distal corner of tibial metaphysic, lines B and C corresponding to corners of tibial metaphysis. Angle A/B defines proximal, A/C distal tibial-angulation. Tibial curvature is defined by distance of line-D parallel to A and tangential to tibial cortex. Normal values were calculated with linear-regression. Intra-/Interreader agreement were tested with a Bland-Altman-plot. Intrareader-agreement: Reader 1 showed a bias of -0.1, standard-deviation of bias was 1.9 and 95 %-limits-of-agreement -3.9- 3.7. Reader 2: -0.01, 2.4 and -4.7- 4.7. Interreader: 0.2, 1.6 and -2.9- 3.3. Angle-A/B ap was 80-100 , increasing with age (86.5-88); angle-AC ap was 82-107 (96.8-90.5), angle-AB lat was 81-107 (93.0-98.0); angle-AC lat was 76-102 (89.5-86.5); depth of curve ap was 0-11 % (8-3.5) and lat 2-13 %, (8.5-3.5). Age dependent tibial bowing can be assessed with this new measurement system and age-related normal-values characterizing physiological tibial bowing in children is established. (orig.)

  20. Tibial bowing in children - what is normal? A radiographic study

    Energy Technology Data Exchange (ETDEWEB)

    Zbinden, Isabella [University of Basel, Department of Radiology, Basel (Switzerland); Rutz, Erich [University Children' s Hospital, Department of Orthopedic Surgery, Basel (Switzerland); Jacobson, Jon A. [University of Michigan, Department of Radiology, Ann Arbor, MI (United States); Magerkurth, Olaf [University Children' s Hospital, Department of Radiology, Basel (Switzerland); Kantonsspital Baden, Department of Radiology, Baden (Switzerland)

    2015-12-15

    To define osseous landmarks on tibia radiographs in order to establish age-related normal values characterizing physiological tibial bowing in children. Five hundred and twenty-six patients aged 0-17 years with normal radiographs of the lower legs were identified and retrospectively reviewed by two blinded radiologists. In anteroposterior (ap)/lateral (lat)-views, 3 lines defined tibial length and angulation. Line-A connecting proximal to distal corner of tibial metaphysic, lines B and C corresponding to corners of tibial metaphysis. Angle A/B defines proximal, A/C distal tibial-angulation. Tibial curvature is defined by distance of line-D parallel to A and tangential to tibial cortex. Normal values were calculated with linear-regression. Intra-/Interreader agreement were tested with a Bland-Altman-plot. Intrareader-agreement: Reader 1 showed a bias of -0.1, standard-deviation of bias was 1.9 and 95 %-limits-of-agreement -3.9- 3.7. Reader 2: -0.01, 2.4 and -4.7- 4.7. Interreader: 0.2, 1.6 and -2.9- 3.3. Angle-A/B ap was 80-100 , increasing with age (86.5-88); angle-AC ap was 82-107 (96.8-90.5), angle-AB lat was 81-107 (93.0-98.0); angle-AC lat was 76-102 (89.5-86.5); depth of curve ap was 0-11 % (8-3.5) and lat 2-13 %, (8.5-3.5). Age dependent tibial bowing can be assessed with this new measurement system and age-related normal-values characterizing physiological tibial bowing in children is established. (orig.)

  1. Trends and correlation analysis in diagnosing turbine rotor bow

    Directory of Open Access Journals (Sweden)

    Tomasz GAŁKA

    2009-01-01

    Full Text Available Permanent rotor bow in a steam turbine is a serious failure which usually demands a time-consuming and costly repair. Its vibration-related symptoms are not specific and qualitative diagnosis typically has to employ results obtained during transients.In a 230 MW power steam turbine, gradual dynamic behavior deterioration was observed, immediately after commissioning. Increase of the fundamental component of rear intermediate-pressure turbine bearing vertical vibration was detected, with the time constant of the order of months. Permanent rotor bow, exceeding 200 m, turned out to be the cause. Rotor repair resulted in a dramatic improvement of dynamic behavior, which, however, soon began to deteriorate again. Vibration spectra had been detected in the off-line mode since commissioning, which allowed to determine vibration time histories.Vibration trends analysis does not provide sufficient information to determine root cause, but allows for eliminating a number of possible malfunctions that give similar symptoms. In particular, the possibility of a sudden random-type damage due to human error is eliminated, which in fact is the most common cause of a permanent bow.Analysis of vibration amplitude correlation between vertical and axial directions reveals very strong correlation between fundamental components in the turbine under consideration, as well in the other one, in which similar failure has been observed. Third unit of the same type, apart from qualitatively different vibration trends, is characterized by correlation factors lower by a few times.This particular case is indicative of the importance of evolutionary symptoms (vibration amplitude time dependence and increase rate, as well as correlation factors in qualitative diagnosis. Such symptoms can be very useful in distinguishing between possible failures which result in similar changes of machine vibration behavior.

  2. Relative locations of the bow shocks of the terrestrial planets

    International Nuclear Information System (INIS)

    The observed bow shock encounters at Mercury, Venus and Mars are least square fit using the same technique so that their sizes and shapes can be intercompared. The shock front of Mercury most resembles the terrestrial shock in shape, and the shock stand off distance is consistent with the observed moment. The shapes of the Venus and Mars shock fronts more resemble each other than the earth's and the stand off distances are consistent with direct interaction of the solar wind with the ionosphere on the dayside. The Venus shock is closer to the planet than the Mars shock suggesting more absorption of the solar wind at Venus

  3. Design of Compact Trapezoidal Bow-Tie Chipless RFID Tag

    OpenAIRE

    Lei Xu; Kama Huang

    2015-01-01

    This paper presents a novel compact design of a low cost fully printable slot-loaded bowtie chipless RFID tag. The tag consists of two trapezoidal metallic patches loaded with multiple slot resonators. Slots with similar size or adjacent frequencies are loaded alternately on two bow-tie patches to double the number of data bits within the UWB frequency band without increasing the mutual coupling between slots. A coding capacity of 12 bits is obtained with 12 slots within a reasonable size of ...

  4. Power aspects of processes in the bow shock region

    Science.gov (United States)

    Sedykh, Pavel

    Bow shock is a powerful transformer of the solar wind kinetic energy into the gas dynamic and electromagnetic energy. The solar wind energy also feeds the ion acceleration process, the generation of waves in the region of bow shock, and the energy necessary to build up the foreshock. A jump of the magnetic field tangential component at front crossing means that the front carries an electric current. The solar wind kinetic energy partly transforms to gas kinetic and electromagnetic energy during its passage through the bow shock front. The transition layer (magnetosheath) can use part of this energy for accelerating of plasma, but can conversely spend part its kinetic energy on the electric power generation, which afterwards may be used by the magnetosphere. Thereby, transition layer can be both consumer (sink) and generator (source) of electric power depending upon special conditions. The direction of the current behind the bow shock front depends on the sign of the IMF B _{z}-component. It is this electric current which sets convection of plasma in motion. The process of current penetration into the magnetosphere is two-step. First, a polarization field is formed that penetrates layer-by-layer into the magnetosphere. More exactly, a pulse corresponding to this field penetrates into the plasma. Then, if the system is inhomogeneous, the flow may redistribute the pressure so that gradients appearing in the plasma induce an electric current. In power terms, this electric current is required to maintain convection in the inhomogeneous system. Any change in the external current through the magnetosphere causes a convection restructuring within a time on the order of travel time of the magnetosonic wave from the magnetopause to the center of the system, because the restructuring wave comes from both flanks. Using the expressions obtained in this paper for normal components of the electric current, the flow of matter brought into the magnetosphere can be estimated. A

  5. Properties of bow-shock sources at the Galactic center

    Science.gov (United States)

    Sanchez-Bermudez, J.; Schödel, R.; Alberdi, A.; Muzić, K.; Hummel, C. A.; Pott, J.-U.

    2014-07-01

    Context. There exists an enigmatic population of massive stars around the Galactic center (GC) that were formed some Myr ago. A fraction of these stars has been found to orbit the supermassive black hole, Sgr A*, in a projected clockwise disk-like structure, which suggests that they were formed in a formerly existing dense disk around Sgr A*. Aims: We focus on a subgroup of objects, the extended, near-infrared (NIR) bright sources IRS 1W, IRS 5, IRS 10W, and IRS 21, that have been suggested to be young, massive stars that form bow shocks through their interaction with the interstellar medium (ISM). Their nature has impeded accurate determinations of their orbital parameters. We aim at establishing their nature and kinematics to test whether they form part of the clockwise disk. Methods: We performed NIR multiwavelength imaging with NACO/VLT using direct adaptive optics (AO) and AO-assisted sparse aperture masking (SAM). We introduce a new method for self-calibration of the SAM point spread function in dense stellar fields. The emission mechanism, morphology, and kinematics of the targets were examined via 3D models, combined with existing models of the gas flow in the central parsec. Results: We confirm previous findings that IRS 21, IRS 1W, and IRS 5 are bow-shocks created by the interaction between mass-losing stars and the interstellar gas. The nature of IRS 10W remains unclear. Our modeling shows that the bow-shock emission is caused by thermal emission, while the scattering of stellar light does not play a significant role. IRS 1W shows a morphology that is consistent with a bow shock produced by an anisotropic stellar wind or by locally inhomogeneous ISM density. Our best-fit models provide estimates of the local proper motion of the ISM in the Northern Arm that agree with previously published models that were based on radio interferometry and NIR spectroscopy. Assuming that all of the sources are gravitationally tied to Sagittarius A*, their orbital planes

  6. Bird species richness and diversity at montane Important Bird Area (IBA) sites in south-eastern Nigeria

    OpenAIRE

    Manu, S; Imong, I.S.; Cresswell, Will

    2010-01-01

    The mountains of south-eastern Nigeria are a western extension of the Cameroon mountain range, which is classified as an endemic bird area (EBA). Unlike its eastern extension in Cameroon, most of the ornithological surveys in the western extension of the Cameroon highlands in Nigeria have produced only limited checklists and inventories. There is a clear need for quantitative baseline data so that conservation problems can be identified. Twenty line transects covering a total transect length ...

  7. 75 FR 59706 - Medicine Bow Hydro, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Science.gov (United States)

    2010-09-28

    ... Bow Pumped Storage Project (Medicine Bow Project) to be located in Carbon County, Idaho. The sole...-foot-high earth and rockfill or concrete-face rockfill dam; creating an 121-acre lower reservoir with a...-long concrete-lined low pressure tunnel; (4) a 19-foot-diameter, 5,060-foot-long high pressure...

  8. 76 FR 65717 - City of Broken Bow, OK; Notice of Availability of Final Environmental Assessment

    Science.gov (United States)

    2011-10-24

    ... Commission's (Commission or FERC) regulations, 18 CFR part 380 (Order No. 486, 52 FR 47897), the Office of Energy Projects has reviewed the application for an Original Major License for the Broken Bow Re... Energy Regulatory Commission City of Broken Bow, OK; Notice of Availability of Final...

  9. 75 FR 33290 - City of Broken Bow, OK; Notice of Availability of Environmental Assessment

    Science.gov (United States)

    2010-06-11

    ... Regulatory Commission's (Commission) regulations, 18 CFR part 380 (Order No. 486, 52 FR 47897), the Office of Energy Projects has reviewed the application for an Original Major License for the Broken Bow Re... Energy Regulatory Commission City of Broken Bow, OK; Notice of Availability of Environmental...

  10. Far-UV bow shock nebula around PSR J0437-4715

    CERN Document Server

    Rangelov, Blagoy; Kargaltsev, Oleg; Durant, Martin; Bykov, Andrei M; Krassilchtchikov, Alexandre

    2016-01-01

    Pulsars traveling at supersonic speeds are often accompanied by cometary bow shocks seen in Halpha. We report on the first detection of a pulsar bow shock in the far-ultraviolet (FUV). We detected it in FUV images of the nearest millisecond pulsar J0437-4715 obtained with the Hubble Space Telescope. The images reveal a bow-like structure positionally coincident with part of the previously detected Halpha bow shock, with an apex at 10'' ahead of the moving pulsar. Its FUV luminosity, L(1250-2000 A) ~ 5x10^28 erg/s, exceeds the Halpha luminosity from the same area by a factor of 10. The FUV emission could be produced by the shocked ISM matter or, less likely, by relativistic pulsar wind electrons confined by strong magnetic field fluctuations in the bow shock. In addition, in the FUV images we found a puzzling extended (~3'' in size) structure overlapping with the limb of the bow shock. If related to the bow shock, it could be produced by an inhomogeneity in the ambient medium or an instability in the bow shock...

  11. Smashing the Guitar: An Evolving Neutron Star Bow Shock

    CERN Document Server

    Chatterjee, S

    2003-01-01

    The Guitar nebula is a spectacular example of an H-alpha bow shock nebula produced by the interaction of a neutron star with its environment. The radio pulsar B2224+65 is traveling at ~800--1600 km/s (for a distance of 1--2 kpc), placing it on the high-velocity tail of the pulsar velocity distribution. Here we report time evolution in the shape of the Guitar nebula, the first such observations for a bow shock nebula, as seen in H-alpha imaging with the Hubble Space Telescope. The morphology of the nebula provides no evidence for anisotropy in the pulsar wind, nor for fluctuations in the pulsar wind luminosity. The nebula shows morphological changes over two epochs spaced by seven years that imply the existence of significant gradients and inhomogeneities in the ambient interstellar medium. These observations offer astrophysically unique, in situ probes of length scales between 5E-4 pc and 0.012 pc. Model fitting suggests that the nebula axis -- and thus the three-dimensional velocity vector -- lies within 20 ...

  12. Quasilinear simulations of interplanetary shocks and Earth's bow shock

    Science.gov (United States)

    Afanasiev, Alexandr; Battarbee, Markus; Ganse, Urs; Vainio, Rami; Palmroth, Minna; Pfau-Kempf, Yann; Hoilijoki, Sanni; von Alfthan, Sebastian

    2016-04-01

    We have developed a new self-consistent Monte Carlo simulation model for particle acceleration in shocks. The model includes a prescribed large-scale magnetic field and plasma density, temperature and velocity profiles and a self-consistently computed incompressible ULF foreshock under the quasilinear approximation. Unlike previous analytical treatments, our model is time dependent and takes full account of the anisotropic particle distributions and scattering in the wave-particle interaction process. We apply the model to the problem of particle acceleration at traveling interplanetary (IP) shocks and Earth's bow shock and compare the results with hybrid-Vlasov simulations and spacecraft observations. A qualitative agreement in terms of spectral shape of the magnetic fluctuations and the polarization of the unstable mode is found between the models and the observations. We will quantify the differences of the models and explore the region of validity of the quasilinear approach in terms of shock parameters. We will also compare the modeled IP shocks and the bow shock, identifying the similarities and differences in the spectrum of accelerated particles and waves in these scenarios. The work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324 (HESPERIA). The Academy of Finland is thanked for financial support. We acknowledge the computational resources provided by CSC - IT Centre for Science Ltd., Espoo.

  13. Design and Analysis of the First BOWS Contest

    Directory of Open Access Journals (Sweden)

    Barni M

    2007-01-01

    Full Text Available The break our watermarking system (BOWS contest was launched in the framework of the activities carried out by the European Network of Excellence for Cryptology ECRYPT. The aim of the contest was to investigate how and when an image watermarking system can be broken while preserving the highest possible quality of the content, in the case the watermarking system is subject to a massive worldwide attack. The great number of participants and the echo that the contest has had in the watermarking community contributed to make BOWS a great success. From a scientific point of view, many insights into the problems attackers have to face with when operating in a practical scenario have been obtained, confirming the threat posed by the sensitivity attack, which turned out to be the most successful attack. At the same time, several interesting modifications of such an attack have been proposed to make it work in a real scenario under limited communication and time resources. This paper describes how the contest has been designed and analyzes the general progress of the attacks during the contest.

  14. Bow Shock Leads the Way for a Speeding Hot Jupiter

    Science.gov (United States)

    Kohler, Susanna

    2015-09-01

    As hot Jupiters whip around their host stars, their speeds can exceed the speed of sound in the surrounding material, theoretically causing a shock to form ahead of them. Now, a study has reported the detection of such a shock ahead of transiting exoplanet HD 189733b, providing a potential indicator of the remarkably strong magnetic field of the planet.Rushing PlanetsDue to their proximity to their hosts, hot Jupiters move very quickly through the stellar wind and corona surrounding the star. When this motion is supersonic, the material ahead of the planet can be compressed by a bow shock and for a transiting hot Jupiter, this shock will cross the face of the host star in advance of the planets transit.In a recent study, a team of researchers by Wilson Cauley of Wesleyan University report evidence of just such a pre-transit. The teams target is exoplanet HD 189733b, one of the closest hot Jupiters to our solar system. When the authors examined high-resolution transmission spectra of this system, they found that prior to the optical transit of the planet, there was a large dip in the transmission of the first three hydrogen Balmer lines. This could well be the absorption of an optically-thick bow shock as it moves past the face of the star.Tremendous MagnetismOperating under this assumption, the authors create a model of the absorption expected from a hot Jupiter transiting with a bow shock ahead of it. Using this model, they show that a shock leading the planet at a distance of 12.75 times the planets radius reproduces the key features of the transmission spectrum.This stand-off distance is surprisingly large. Assuming that the location of the bow shock is set by the point where the planets magnetospheric pressure balances the pressure of the stellar wind or corona that it passes through, the planetary magnetic field would have to be at least 28 Gauss. This is seven times the strength of Jupiters magnetic field!Understanding the magnetic fields of exoplanets is

  15. Zircon U-Pb age and geochemical characteristics of the granites in Chenming area,southeastern Xiao Hinggan mountains%小兴安岭东南部晨明地区早古生代花岗岩锆石U-Pb年龄及岩石地球化学特征

    Institute of Scientific and Technical Information of China (English)

    魏连喜; 孙丰月; 薛明轩; 于晓飞; 孙乃权

    2013-01-01

    Chenming pluton is located in the southeastern Xiao Hinggan mountains,composed of monzonitic granite and granodiorite.Combined with the Th/U ratios of zircons in all samples which possess oscillatory growth ring,it suggests that these zircons are magmatic in origin.LA-ICP MS U-Pb dating results show that the forming age is 432.8±1.2 and 431.9±1.7Ma,which indicates the Early Silurian.According to its geochemical characteristics,the Chenming pluton belongs to high potassium calc-alkaline series in category.Its ACNK value is ranging between 1.16~1.40,which indicates to be peraluminous granite in nature.The trace elements are enriched by LILE(Rb,Ba,U and Th)and LREE,with loss of HFSE(Nb,Ta,Ti),P,Sr and HREE,which implies that the Chenming pluton originated mainly from the partial melting of lower crust material,and its peraluminous characteristics suggested its forming in the environment of continental crust thickening.Combined with the results of previous researches,the Chenming pluton formed in the collision backgroud of Songnen massif with Jiamusi massif,that means the collision of Songnen massif and Jiamusi massif may occur in the Early Silurian.%晨明岩体位于小兴安岭东南段,其岩石组合为花岗闪长岩和二长花岗岩.所测定样品中的锆石均具有振荡生长环带,结合Th/U比值,表明这些锆石为岩浆成因,LA-ICP MS U-Pb测年结果显示,其形成时代分别为432.8±1.2 Ma和431.9±1.7Ma,即早志留世.晨明岩体的地球化学特征显示,其属于高钾钙碱性系列,ACNK值为1.16~1.40,属于过铝质花岗岩;微量元素表现出富集大离子亲石元素(Rb、Ba、U和Th)和轻稀土元素,亏损高场强元素(Nb、Ta、Ti)和P、Sr以及重稀土元素.上述地球化学特征暗示其主要来源于下地壳物质的部分熔融,样品的过铝质特征暗示其形成于陆壳加厚环境.结合前人研究成果,认为晨明岩体形成于松嫩地块和佳木斯地块的碰撞拼合环境,即松嫩地块

  16. Simulation of the oscillation regimes of bowed bars: a non-linear modal approach

    Science.gov (United States)

    Inácio, Octávio; Henrique, Luís.; Antunes, José

    2003-06-01

    It is still a challenge to properly simulate the complex stick-slip behavior of multi-degree-of-freedom systems. In the present paper we investigate the self-excited non-linear responses of bowed bars, using a time-domain modal approach, coupled with an explicit model for the frictional forces, which is able to emulate stick-slip behavior. This computational approach can provide very detailed simulations and is well suited to deal with systems presenting a dispersive behavior. The effects of the bar supporting fixture are included in the model, as well as a velocity-dependent friction coefficient. We present the results of numerical simulations, for representative ranges of the bowing velocity and normal force. Computations have been performed for constant-section aluminum bars, as well as for real vibraphone bars, which display a central undercutting, intended to help tuning the first modes. Our results show limiting values for the normal force FN and bowing velocity ẏbow for which the "musical" self-sustained solutions exist. Beyond this "playability space", double period and even chaotic regimes were found for specific ranges of the input parameters FN and ẏbow. As also displayed by bowed strings, the vibration amplitudes of bowed bars also increase with the bow velocity. However, in contrast to string instruments, bowed bars "slip" during most of the motion cycle. Another important difference is that, in bowed bars, the self-excited motions are dominated by the system's first mode. Our numerical results are qualitatively supported by preliminary experimental results.

  17. The bowed catheter sign: a risk for pericardial tamponade

    Energy Technology Data Exchange (ETDEWEB)

    Towbin, Richard [Phoenix Children' s Hospital, Department of Radiology, Phoenix, AZ (United States)

    2008-03-15

    The use of a central venous catheter (CVC) has become commonplace in the care of children with a wide variety of medical and surgical problems. Complications resulting from the insertion of these catheters are well recognized and can be life-threatening. When a temporary CVC or other catheter is inserted into the central venous system it is secured to the skin with a combination of sutures and sterile dressing. This fixes the catheter in place and does not allow it to retract, thereby putting pressure on the right atrial wall via the catheter tip if it is too long. The probability of wall penetration is increased if a catheter or device is tapered at the point of contact. The purpose of this case report is to present the bowed catheter sign and to review the anatomy of the cavotricuspid isthmus, a possible predisposing factor to cardiac perforation and tamponade. (orig.)

  18. On the peculiar shapes of some pulsar bow-shock nebulae

    Science.gov (United States)

    Bandiera, Rino

    Pulsar bow-shock nebulae are pulsar-wind nebulae formed by the direct interaction of pulsar relativistic winds with the interstellar medium. The bow-shock morphology, well outlined in Hα for some objects, is an effect of the supersonic pulsar motion with respect to the ambient medium. However, in a considerable fraction of cases (e.g. the nebulae associated to PSR B2224+65, PSR B0740-28, PSR J2124-3358) clear deviations from the classical bow shock shape are observed. Such deviations are usually interpreted as due to ambient density gradients and/or to pulsar-wind anisotropies. Here I present a different interpretation, aiming at explaining deviations from the standard morphology as signs of the peculiar physical conditions present in these objects. Using dimensional arguments, I show that, unlike normal pulsar-wind nebulae, in pulsar bow-shock nebulae the mean free path of the highest-energy particles may be comparable with the bow-shock head. I then investigate whether this may affect the shape of the bow-shock; for instance, whether a conical bow shock (like that observed in the "Guitar", the nebula associated to PSR B2224+65) does really imply an ambient density gradient. Finally, I discuss some other possible signatures of these high-energy, long mean-free-path particles.

  19. On the shape and motion of the Earth's bow shock

    Science.gov (United States)

    Meziane, K.; Alrefay, T. Y.; Hamza, A. M.

    2014-04-01

    Multipoint-measurements by the magnetic field Cluster-FGM (Flux Gate Magnetometer) are used to determine the local shock normal, and in turn allow the study of shock location shape and the velocity of the Earth's bow shock. The shock crossings cover orbits in which the spacecraft separation is of the order of ~600 km or less. A data selection of 133 bow shock crossings, ranging from quasi-steady perpendicular to moderately noisy oblique geometries, have been analyzed using a standard timing analysis. Prior to applying the timing technique, the magnetic field fluctuations, when present, are suppressed using low band-pass filtering. The present study contributes to similar studies conducted in the past and available in the literature through the inclusion of a larger data set. The shock standoff distance is determined conjointly with a paraboloid model and the results from a timing analysis. A statistical study reveals a standoff distance well in agreement with the standard gas dynamics model prediction for high Mach number MA. We have also found that for about half the crossings, the timing shock normals agree, within 11°, with a conic-based shock model. Our results strongly indicate that the motion of the shock is predominantly along the Sun-Earth direction; a departure from this direction is not related to the shock-crossing location. Shock velocities below ~80 km/s satisfactorily follow a nearly Gaussian distribution with zero mean and a standard deviation of ~42 km/s. Finally, we show that high speed motions are correlated with sharp increases in the solar wind upstream ram pressure, and are consistent with gas dynamics model predictions.

  20. Land changes and their driving forces in the Southeastern United States

    Science.gov (United States)

    Napton, D.E.; Auch, R.F.; Headley, R.; Taylor, J.L.

    2010-01-01

    The ecoregions of the Middle Atlantic Coastal Plain, Southeastern Plains, Piedmont, and Blue Ridge provide a continuum of land cover from the Atlantic Ocean to the highest mountains in the East. From 1973 to 2000, each ecoregion had a unique mosaic of land covers and land cover changes. The forests of the Blue Ridge Mountains provided amenity lands. The Piedmont forested area declined, while the developed area increased. The Southeastern Plains became a commercial forest region, and most agricultural lands that changed became forested. Forests in the Middle Atlantic Coastal Plain declined, and development related to recreation and retirement increased. The most important drivers of land conversion were associated with commercial forestry, competition between forest and agriculture, and economic and population growth. These and other drivers were modified by each ecoregion's unique suitability and land use legacies with the result that the same drivers often produced different land changes in different ecoregions. ?? Springer-Verlag 2009.

  1. Clause Types in Southeastern Tepehuan.

    Science.gov (United States)

    Willett, Thomas L.

    The clause in Southeastern Tepehuan consists of a predicate, its associated arguments, and other modifying elements. This paper seeks to show the various types of semantic and surface clauses and the relation between them. The semantic clause consists of various semantic components, both nuclear and peripheral, semantic prosodies, and certain…

  2. Sentence Components in Southeastern Tepehuan.

    Science.gov (United States)

    Willett, Thomas L.

    This paper explores the intra-clausal relations of minimal locutionary and illocutionary force in Southeastern Tepehuan. It surveys the semantic and syntactic sentence types with primary reference to grammatical relations. The semantic propositional structures, along with their modal parameters and other semantic prosodies are discussed in Section…

  3. Bow shock fragmentation driven by a thermal instability in laboratory-astrophysics experiments

    OpenAIRE

    Suzuki-Vidal, F.; Lebedev, S. V.; Ciardi, A.; Pickworth, L. A.; Rodriguez, R.; Gil, J. M.; Espinosa, G. (Gaudencio); Hartigan, P.; Swadling, G. F.; Skidmore, J.; Hall, G. N.; Bennett, M; Bland, S. N.; Burdiak, G.; de Grouchy, P.

    2015-01-01

    The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counter-streaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame and the exper...

  4. The geology and tectonic significance of the Big Creek Gneiss, Sierra Madre, southeastern Wyoming

    Science.gov (United States)

    Jones, Daniel S.

    The Big Creek Gneiss, southern Sierra Madre, southeastern Wyoming, is a heterogeneous suite of upper-amphibolite-facies metamorphic rocks intruded by post-metamorphic pegmatitic granite. The metamorphic rocks consist of three individual protolith suites: (1) pre- to syn-1780-Ma supracrustal rocks including clastic metasedimentary rocks, calc-silicate paragneiss, and metavolcanic rocks; (2) a bimodal intrusive suite composed of metagabbro and granodiorite-tonalite gneiss; and (3) a younger bimodal suite composed of garnet-bearing metagabbronorite and coarse-grained granitic gneiss. Zircons U-Pb ages from the Big Creek Gneiss demonstrate that: (1) the average age of detrital zircons in the supracrustal rocks is ~1805 Ma, requiring a significant source of 1805-Ma (or older) detritus during deposition, possibly representing an older phase of arc magmatism; (2) the older bimodal igneous suite crystallized at ~1780 Ma, correlative with arc-derived rocks of the Green Mountain Formation; (3) the younger bimodal igneous suite crystallized at ~1763 Ma, coeval with the extensional(?) Horse Creek anorthosite complex in the Laramie Mountains and Sierra Madre Granite batholith in the southwestern Sierra Madre; (4) Big Creek Gneiss rocks were tectonically buried, metamorphosed, and partially melted at ~1750 Ma, coeval with the accretion of the Green Mountain arc to the Wyoming province along the Cheyenne belt; (5) the posttectonic granite and pegmatite bodies throughout the Big Creek Gneiss crystallized at ~1630 Ma and are correlative with the 'white quartz monzonite' of the south-central Sierra Madre. Geochemical analysis of the ~1780-Ma bimodal plutonic suite demonstrates a clear arc-affinity for the mafic rocks, consistent with a subduction environment origin. The granodioritic rocks of this suite were not derived by fractional crystallization from coeval mafic magmas, but are instead interpreted as melts of lower-crustal mafic material. This combination of mantle

  5. Bow-tie topological features of metabolic networks and the functional significance

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jing; TAO Lin; YU Hong; LUO JianHua; GAO ZhiWei; LI YiXue

    2007-01-01

    Exploring the structural topology of genome-based large-scale metabolic network is essential for in vestigating possible relations between structure and functionality. Visualization would be helpful for obtaining immediate information about structural organization. In this work, metabolic networks of 75 organisms were investigated from a topological point of view. A spread bow-tie model was proposed to give a clear visualization of the bow-tie structure for metabolic networks. The revealed topological pattern helps to design more efficient algorithm specifically for metabolic networks. This coarsegrained graph also visualizes the vulnerable connections in the network, and thus could have important implication for disease studies and drug target identifications. In addition, analysis on the reciprocal links and main cores in the GSC part of bow-tie also reveals that the bow-tie structure of metabolic networks has its own intrinsic and significant features which are significantly different from those of random networks.

  6. The Effect of Buffer Bow Structures on Collision Damages of Oil Tankers

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Pedersen, Preben Terndrup; Friis-Hansen, Peter

    2007-01-01

    In order to investigate the effectiveness of buffer bow structures on prevention of oil spills in tanker collisions, probabilistic collision damage analyses were performed using a newly developed Simplified Ship Collision Analysis Tool (SSCAT). Monte Carlo Simulation (MCS) was carried out using...... the striking ships use conventional bulbous bows. The probability of oil spill from the VLCC, given a collision, is estimated and the risk reducing effect of introducing buffer bow structures is discussed....... SSCAT for collision scenarios where striking ships at various speeds, sizes and bulb shapes collide perpendicularly with a VLCC in fully loaded condition. The probability of oil spill from the struck VLCC in cases where all the striking ships use buffer bulbous bows was compared with the case where all...

  7. Effect of Ship Bow Overhang on Water Shipping for Ship Advancing in Regular Head Waves

    Institute of Scientific and Technical Information of China (English)

    Abdeljalil Benmansour; Benameur Hamoudi; Lahouari Adjlout

    2016-01-01

    This paper presents the results of an experimental investigation dealing with the effect of bow overhang extensions on the quantity of shipping water over the foredeck in case of ships advancing in regular head waves. To perform this investigation, a series of free-running tests was conducted in regular waves using an experimental model of a multipurpose cargo ship to quantify the amount of shipping water. The tests were performed on five bow overhang variants with several combinations of wavelength and ship speed conditions. It was observed that the quantity of shipping water was affected by some parameters such as wavelength, ship speed, and bow shape in terms of an overhang extension. The results show the significant influence of an overhang extension, which is associated with the bow flare shape, on the occurrence of water shipping. These results involve the combined incoming regular waves and model speed.

  8. Trade-off between leaf size and number in current-year twigs of deciduous broad-leaved woody species at different altitudes on Qingliang Mountain, southeastern China%清凉峰不同海拔木本植物小枝内叶大小-数量权衡关系

    Institute of Scientific and Technical Information of China (English)

    杨冬梅; 占峰; 张宏伟

    2012-01-01

    Aims Trade-offs are fundamental to life-history strategies theory, and the leaf size and number trade-off is an important determinant of leaf-size evolution. It also has been proposed that this trade-off is dependent on habitat, but this is not well tested. Our objectives were to test whether the negative, isometric relationship between leaf size and number is conserved in different habitats and to explore the effects of altitude change on the relationship between the leaf size and number.Methods Leaf area, mass and number and twig mass and stem mass of current-year twigs were measured for 61 deciduous broad-leaved woody species within three altitude-based habitats on Qingliang Mountain, southeastern China. The standardized major axis estimation method and the phylogenetically independent contrast method were used to examine the scaling relationship between leaf size (leaf mass and leaf area) and leafing intensity (twig mass and stem mass) within current-year twigs.Important findings Significantly negative and isometric scaling relationships between leaf size and leafing intensity were found to be consistent in all three altitude-based habitats, regardless of whether leaf/twig size was expressed as area or mass. However, the intercepts of these relationships significantly decreased with increasing altitude, suggesting that habitats constrain the leaf size that can be supported by a given leafing intensity. The middle-attitude species usually had significant upper shifts along the common slopes relative to the high-altitude species. This suggested that the middle altitude is a more suitable habitat with high nutrients and moderate climate conditions for plants, compared to the high altitude with low temperatures and nutrients.%权衡关系是生活史对策理论的基础,叶大小-数量的权衡关系对理解叶大小进化具有重要的意义.该研究以单叶面积和单叶片干重表示叶大小,用小枝干重和小枝茎干重

  9. Highly modular bow-tie gene circuits with programmable dynamic behavior

    OpenAIRE

    Prochazka, Laura; Angelici, Bartolomeo; Haefliger, Benjamin; Benenson, Yaakov

    2014-01-01

    Synthetic gene circuits often require extensive mutual optimization of their components for successful operation, while modular and programmable design platforms are rare. A possible solution lies in the “bow-tie” architecture, which stipulates a focal component - a “knot” - uncoupling circuits’ inputs and outputs, simplifying component swapping, and introducing additional layer of control. Here we construct, in cultured human cells, synthetic bow-tie circuits that transduce microRNA inputs i...

  10. Bow-tie topological features of metabolic networks and the functional significance

    OpenAIRE

    Jing, Zhao; Lin, Tao; Hong, Yu; Jian-Hua, Luo; Cao, Z W; Yixue, Li

    2006-01-01

    Exploring the structural topology of genome-based large-scale metabolic network is essential for investigating possible relations between structure and functionality. Visualization would be helpful for obtaining immediate information about structural organization. In this work, metabolic networks of 75 organisms were investigated from a topological point of view. A spread bow-tie model was proposed to give a clear visualization of the bow-tie structure for metabolic networks. The revealed top...

  11. Numerical and experimantal analysis of a shaft bow influence on a rotor to stator contact dynamics:

    OpenAIRE

    Braut, Sanjin; Butković, Mirko; Žigulić, Roberto

    2008-01-01

    The shaft bow problem presents a real situation especially in case of slender rotors. This paper investigates the shaft bow influence on the rotor-stator contact dynamics. For this purpose the rotor is described as a simple Jeffcott model and the stator as an elastically suspended rigid ring. To test the numerical model, except a usual run down analysis, an emergency shut down after the sudden rotor unbalance increase is also analyzed. Numerical integration is carried out by the fourth-order ...

  12. Development of the Joyo MK-II core bowing reactivity calculation code

    Energy Technology Data Exchange (ETDEWEB)

    Tabuchi, Shiro; Torimaru, Tadahiko; Yoshida, Akihiro; Aoyama, Takafumi [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1999-09-01

    The study on the passive safety test by using the Experimental Fast Reactor Joyo has been performed to demonstrate the inherent safety of fast breeder reactors. In this study, emphasis was placed on the improvement on the accuracy of the feedback reactivity analysis. As a bowing reactivity might play a significant roll in ATWS analysis because of its effectively short time constant and relatively large magnitude, an emphasis was placed upon the evaluation of the analysis precision of bowing reactivity. Taking into account of the refueling and irradiation history of the individual core component, the core bowing behavior in Joyo has been analyzed by using the MK-II core management code system MAGI, the interface code TETRAS which interpolate neutron flux and coolant temperature at the position of wrapper tube, and the core bowing calculation code BEACON. Calculation accuracy of above mentioned system was evaluated through the comparison of calculated and measured permanent distortion of subassemblies. In 1996, core bowing reactivity was calculated by AURORA code using the above calculated bowing behavior of individual core component as input. But because an approximate two dimensional material reactivity worth map was utilized in AURORA, it was made clear that some amount of error caused by extrapolation could not be neglected. Therefore calculation code ARCHCOM (Analysis of Reactivity Change due to Core Mechanics) which utilize three dimensional material reactivity worth map as input was developed for the Joyo MK-II core bowing reactivity calculation. This code reduces above mentioned extrapolation error that used to be occurred at isolated core component, such as control rod or irradiation rig and at the interface region between fuel and reflector which had sharp bowing reactivity worth gradient. (author)

  13. On the observability of bow shocks of Galactic runaway OB stars

    CERN Document Server

    Meyer, D M -A; Kuiper, R; Kley, W

    2016-01-01

    Massive stars that have been ejected from their parent cluster and supersonically sailing away through the interstellar medium (ISM) are classified as exiled. They generate circumstellar bow shock nebulae that can be observed. We present two-dimensional, axisymmetric hydrodynamical simulations of a representative sample of stellar wind bow shocks from Galactic OB stars in an ambient medium of densities ranging from n_ISM=0.01 up to 10.0/cm3. Independently of their location in the Galaxy, we confirm that the infrared is the most appropriated waveband to search for bow shocks from massive stars. Their spectral energy distribution is the convenient tool to analyze them since their emission does not depend on the temporary effects which could affect unstable, thin-shelled bow shocks. Our numerical models of Galactic bow shocks generated by high-mass (~40 Mo) runaway stars yield H$\\alpha$ fluxes which could be observed by facilities such as the SuperCOSMOS H-Alpha Survey. The brightest bow shock nebulae are produc...

  14. Geologic map of the Paintbrush Canyon Area, Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, R.P. [Geological Survey, Denver, CO (United States); Drake, R.M. II [Pacific Western Technologies, Ltd., Lakewood, CO (United States)

    1998-11-01

    This geologic map is produced to support site characterization studies of Yucca Mountain, Nevada, site of a potential nuclear waste storage facility. The area encompassed by this map lies between Yucca Wash and Fortymile Canyon, northeast of Yucca Mountain. It is on the southern flank of the Timber Mountain caldera complex within the southwest Nevada volcanic field. Miocene tuffs and lavas of the Calico Hills Formation, the Paintbrush Group, and the Timber Mountain Group crop out in the area of this map. The source vents of the tuff cones and lava domes commonly are located beneath the thickest deposits of pyroclastic ejecta and lava flows. The rocks within the mapped area have been deformed by north- and northwest-striking, dominantly west-dipping normal faults and a few east-dipping normal faults. Faults commonly are characterized by well developed fault scarps, thick breccia zones, and hanging-wall grabens. Latest movement as preserved by slickensides on west-dipping fault scarps is oblique down towards the southwest. Two of these faults, the Paintbrush Canyon fault and the Bow Ridge fault, are major block-bounding faults here and to the south at Yucca Mountain. Offset of stratigraphic units across faults indicates that faulting occurred throughout the time these volcanic units were deposited.

  15. Whistler wave bursts upstream of the Uranian bow shock

    Science.gov (United States)

    Smith, Charles W.; Goldstein, Melvyn L.; Wong, Hung K.

    1989-01-01

    Observations of magnetic field wave bursts upstream of the Uranian bow shock are reported which were recorded prior to the inbound shock crossing. Three wave types are identified. One exhibits a broad spectral enhancement from a few millihertz to about 50 mHz and is seen from 17 to 10 hr prior to the inbound shock crossing. It is argued that these waves are whistler waves that have propagated upstream from the shock. A second wave type has a spacecraft frame frequency between 20 and 40 mHz, is seen only within or immediately upstream of the shock pedestal, is right-hand polarized in the spacecraft frame, and has a typical burst duration of 90 s. The third wave type has a spacecraft frame frequency of about 0.15 Hz, is seen exclusively within the shock pedestal, is left-hand polarized in the spacecraft frame, and has a burst duration lasting up to 4 min. It is argued that the low-frequency bursts are whistler waves with phase speed comparable to, but in excess of, the solar wind speed.

  16. Whistler waves associated with the Uranian bow shock - Outbound observations

    Science.gov (United States)

    Smith, Charles W.; Wong, Hung K.; Goldstein, Melvyn L.

    1991-01-01

    High-resolution magnetic field measurements from the first outbound crossing of the Uranian bowshock by the Voyager 2 spacecraft between January 27 and 30, 1986, are examined. Evidence is found of enhanced whistler wave activity in the vicinity of three shock crossings but little or no evidence of such activity elsewhere. Two wave events display two separate and simultaneous wave enhancements each. From an investigation of these events using high-resolution field data, it is concluded that they are analogous to those whistler waves upstream of the earth's bow shock that are driven by beams of electrons. An instability analysis is presented to show that a single electron beam with reasonable parameters can penetrate both of the upstream and downstream of a shock crossing. This event displays only one relatively broad spectral enhancement in the same frequency regime and is left-hand polarized in the spacecraft frame. It is argued that this event is the result of a gyrating proton distribution associated with the oblique shock.

  17. Motion Prediction of Catamaran with a Semisubmersible Bow in Wave

    Directory of Open Access Journals (Sweden)

    Sun Hanbing

    2016-01-01

    Full Text Available Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a short-term irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion.

  18. Multi-Spacecraft Investigation of Terrestrial Bow Shock: Cluster Observations

    Science.gov (United States)

    Kruparova, O.; Krupar, V.; Santolik, O.; Soucek, J.; Safrankova, J.; Nemecek, Z.; Nemec, F.; Maksimovic, M.

    2015-12-01

    Due to the interaction of the solar wind with the Earth's magnetosphere, a permanent collisionless bow shock (BS) is formed in front of the nose of the magnetopause. We investigate a large number of BS crossings observed by the Cluster spacecraft between years 2001 and 2015. The FGM instruments provide us with magnetic field measurements sampled at 22 Hz, which is sufficient for a precise identification of BS crossings. We compare observed BS locations with distances predicted by gas dynamical models based on upstream plasma parameters in the solar wind. We achieve a very good agreement in a case of a paraboloid with the Earth fixed in a focus point. We use a simple timing method for the estimation of a BS normal and velocity along this normal. We found that the deviations of calculated BS normals from the paraboloid shape are within 20 degrees. We compare calculated BS velocities with several upstream parameters. We also investigate BS ramp thickness which is comparable to the Larmor radius in the case of quasi-perpendicular BS crossings.

  19. Design of Compact Trapezoidal Bow-Tie Chipless RFID Tag

    Directory of Open Access Journals (Sweden)

    Lei Xu

    2015-01-01

    Full Text Available This paper presents a novel compact design of a low cost fully printable slot-loaded bowtie chipless RFID tag. The tag consists of two trapezoidal metallic patches loaded with multiple slot resonators. Slots with similar size or adjacent frequencies are loaded alternately on two bow-tie patches to double the number of data bits within the UWB frequency band without increasing the mutual coupling between slots. A coding capacity of 12 bits is obtained with 12 slots within a reasonable size of 35 mm × 33 mm. RCS of the tag has been given by simulation. Measurements have been done using a bistatic radar configuration in the frequency domain and transmission coefficient is measured. The agreement between the simulation and measurement validates this new concept of design. This tag has high data capacity and low cost and can be directly printed on product such as personal ID, credit cards, paper, and textile because it needs only one conductive layer.

  20. Comparison of accelerated ion populations observed upstream of the bow shocks at Venus and Mars

    Directory of Open Access Journals (Sweden)

    M. Yamauchi

    2011-03-01

    Full Text Available Foreshock ions are compared between Venus and Mars at energies of 0.6~20 keV using the same ion instrument, the Ion Mass Analyser, on board both Venus Express and Mars Express. Venus Express often observes accelerated protons (2~6 times the solar wind energy that travel away from the Venus bow shock when the spacecraft location is magnetically connected to the bow shock. The observed ions have a large field-aligned velocity compared to the perpendicular velocity in the solar wind frame, and are similar to the field-aligned beams and intermediate gyrating component of the foreshock ions in the terrestrial upstream region. Mars Express does not observe similar foreshock ions as does Venus Express, indicating that the Martian foreshock does not possess the intermediate gyrating component in the upstream region on the dayside of the planet. Instead, two types of gyrating protons in the solar wind frame are observed very close to the Martian quasi-perpendicular bow shock within a proton gyroradius distance. The first type is observed only within the region which is about 400 km from the bow shock and flows tailward nearly along the bow shock with a similar velocity as the solar wind. The second type is observed up to about 700 km from the bow shock and has a bundled structure in the energy domain. A traversal on 12 July 2005, in which the energy-bunching came from bundling in the magnetic field direction, is further examined. The observed velocities of the latter population are consistent with multiple specular reflections of the solar wind at the bow shock, and the ions after the second reflection have a field-aligned velocity larger than that of the de Hoffman-Teller velocity frame, i.e., their guiding center has moved toward interplanetary space out from the bow shock. To account for the observed peculiarity of the Martian upstream region, finite gyroradius effects of the solar wind protons compared to the radius of the bow shock curvature and

  1. Exploiting biomechanical degrees of freedom for fast and accurate changes in movement direction: coordination underlying quick bow reversals during continuous cello bowing

    Directory of Open Access Journals (Sweden)

    Julius eVerrel

    2013-04-01

    Full Text Available Theoretical and empirical evidence suggests that accurate and efficient motor performance may be achieved by task-specific exploitation of biomechanical degrees of freedom. We investigate coordination of the right arm in a task requiring a sudden yet precisely controlled reversal of movement direction: bow reversals during continuous (legato tone production on a stringed instrument. Ten advanced or professional cello players (at least ten years of practice and ten age-matched novice players took part in the study. Kinematic data from the bow and the right arm were analyzed in terms of velocity and acceleration profiles, as well as temporal coordination along the arm. As expected, experts’ bow velocity and acceleration profiles differed markedly from those of novice participants, with higher peak accelerations and quicker direction changes. Importantly, experts achieved the change in movement direction with a single acceleration peak while novices tended to use multiple smaller acceleration peaks. Experts moreover showed a proximal-distal gradient in timing and amplitudes of acceleration peaks, with earlier and lower-amplitude reversals at more proximal joints. We suggest that this coordination pattern allows generating high accelerations at the end effector while reducing the required joint torques at the proximal joints. This may underlie experts’ ability to produce fast bow reversals efficiently and with high spatiotemporal accuracy. The findings are discussed in terms of motor control theory as well as potential implications for musicians’ performance and health.

  2. Ship Bow Force-Deformation Curves for Ship-Impact Demand of Bridges considering Effect of Pile-Cap Depth

    OpenAIRE

    Wei Fan; Wancheng Yuan

    2014-01-01

    Since static analysis procedures in the vessel impact-resistant design codes neglect dynamic amplification effects related to bridge mass, ship-impact responses of bridges may be potentially underestimated. For this reason, several dynamic vessel-impact analysis techniques had been recently proposed, where a force-deformation curve was employed to model the vessel bow stiffness. Most of the recent works mainly focused on the force-deformation curves of the barge bows rather than the ship bows...

  3. A bow-shaped thermal structure traveling upstream of the zonal wind flow of Venus atmosphere

    Science.gov (United States)

    Taguchi, Makoto; Fukuhara, Tetsuya; Imamura, Takeshi; Kouyama, Toru; Nakamura, Masato; Sato, Takao M.; Ueno, Munetaka; Suzuki, Makoto; Iwagami, Naomoto; Sato, Mitsuteru; Hashimoto, George L.; Takagi, Seiko; Akatsuki Science Team

    2016-10-01

    The Longwave Infrared Camera (LIR) onboard the Japanese Venus orbiter Akatsuki acquires a snap shot of Venus in the middle infrared region, and provides a brightness temperature distribution at the cloud-top altitudes of about 65 km. Hundreds of images taken by LIR have been transferred to the ground since the successful Venus orbit insertion of Akatsuki on Dec. 7, 2015. Here we report that a bow shaped thermal structure extending from the northern high latitudes to the southern high latitudes was found in the brightness temperature map on Dec. 7, 2015, and that it lasted for four days at least surprisingly at almost same geographical position. The bow shape structure looks symmetrical with the equator, and consists of a high temperature region in east or upstream of the background strong westward wind or the super rotation of the Venus atmosphere followed by a low temperature region in west with an amplitude of 5 K. It appeared close to the evening terminator in the dayside, and seems not to have stayed in the same local time rather to have co-rotated with the slowly rotating ground where the western part of Aphrodite Continent was below the center of the bow shape. Meridionally aligned dark filaments similar to the bow shape structure in shape but in much smaller scale were also identified in the brightness temperature map on Dec. 7, and they propagated upstream of the zonal wind as well. The bow shape structure disappeared when LIR observed the same local time and longitude in the earliest opportunity on Jan. 16, 2016. Similar events, though their amplitudes were less than 1 K, were found on Apr. 15 and 26, 2016, but they appeared in different local times and longitudes. A simulation of a gravity wave generated in the lower atmosphere and propagating upward reproduces the observed bow shape structure. The bow shape structure could be a signature of transferring momentum from the ground to the upper atmosphere.

  4. Possible generation mechanisms of low-frequency waves /less than about 50 Hz/ with application to the bow shock plasma

    Science.gov (United States)

    Dangelo, N.

    1979-01-01

    Generation mechanisms of waves observed at the earth's bow shock or in its vicinity within the frequency range extending up to about 50 Hz are reviewed. Observations and theories regarding waves in the solar wind upstream of the bow shock (both low-frequency 0.01-0.05 Hz and high-frequency 0.5-4 Hz waves), waves in the bow shock itself and magnetosheath waves arising from processes of generation or amplification in the bow shock are considered. Hydromagnetic, ion-acoustic and whistler type waves are discussed.

  5. Oxygen foreshock of Mars and its implication on ion acceleration in the bow shock

    Science.gov (United States)

    Yamauchi, Masatoshi; Lundin, Rickard; Frahm, Rudy; Sauvaud, Jean-Andre; Holmstrom, Mats; Barabash, Stas

    2016-04-01

    Ion acceleration inside the bow shock is one of the poorly understood phenomena that has been observed for more than 30 years as the foreshock phenomena. While the Fermi-acceleration mechanism explains the diffuse component of foreshock ions, we still do not know the detailed mechanism that produces the discrete intense ions flowing along the local magnetic field direction (with and without gyration). One of the reasons for such difficulty is that majority of the bow shock study was performed for the Earth's case where Oxygen ions cannot be used to understand the acceleration mechanisms. The planetary oxygen ions that reach the Earth's bow shock have already been significantly accelerated, and are not adequate for such a study. In this sense the Martian bow shock is an ideal place to study the acceleration mechanisms leading to foreshock ions, although the nature of the bow shock is slightly different between the Earth and Mars (Yamauchi et al., 2011). On 21 September 2008, the Mars Express (MEX) Ion Mass Analyser (IMA) detected foreshock-like discrete distributions of oxygen ions at around 1 keV in the solar wind attached to the bow shock. This was the first time that a substantial amount of planetary oxygen was observed upstream of the bow shock. The oxygen energy increased from low energy (location from the oxygen by about 1000 km, at a slightly higher energy, and flowing in a slightly different direction than the oxygen ions. Both protons and oxygen ions are flowing anti-sunward at different angles with respect to the solar wind direction. The observation is consistent with an electric potential barrier at the bow shock that simultaneously accelerates the planetary oxygen ions outward (to form the foreshock oxygen ions) and reflects a portion of the solar wind (to form the foreshock protons). Yamauchi, M., et al. (2011): Comparison of accelerated ion populations observed upstream of the bow shocks at Venus and Mars, Ann. Geophys., 29(3), 511-528, doi:10

  6. Scattering of field-aligned beam ions upstream of Earth's bow shock

    Directory of Open Access Journals (Sweden)

    A. Kis

    2007-03-01

    Full Text Available Field-aligned beams are known to originate from the quasi-perpendicular side of the Earth's bow shock, while the diffuse ion population consists of accelerated ions at the quasi-parallel side of the bow shock. The two distinct ion populations show typical characteristics in their velocity space distributions. By using particle and magnetic field measurements from one Cluster spacecraft we present a case study when the two ion populations are observed simultaneously in the foreshock region during a high Mach number, high solar wind velocity event. We present the spatial-temporal evolution of the field-aligned beam ion distribution in front of the Earth's bow shock, focusing on the processes in the deep foreshock region, i.e. on the quasi-parallel side. Our analysis demonstrates that the scattering of field-aligned beam (FAB ions combined with convection by the solar wind results in the presence of lower-energy, toroidal gyrating ions at positions deeper in the foreshock region which are magnetically connected to the quasi-parallel bow shock. The gyrating ions are superposed onto a higher energy diffuse ion population. It is suggested that the toroidal gyrating ion population observed deep in the foreshock region has its origins in the FAB and that its characteristics are correlated with its distance from the FAB, but is independent on distance to the bow shock along the magnetic field.

  7. Application of high-turning bowed compressor stator to redesign of highly loaded fan stage

    Institute of Scientific and Technical Information of China (English)

    Shaobin LI; Jiexian SU; Zhongqi WANG

    2008-01-01

    A redesign of a highly loaded fan stage by using high-turning bowed compressor stator was conducted. The original tandem stator was replaced by the highly loaded bowed stator which was applicable to highly sub-sonic flow conditions. 3D contouring technique and local modification of blade were applied to the design of the bowed blade in order to improve the aerodynamic per-formance and the matching of the rotor and stator blade rows. Performance curves at different rotating speeds and performances at different operating points for both the original fan stage and redesigned fan stage were obtained by numerical simulations. The results show that the highly loaded bowed stator can be used not only to improve the structure and the aerodynamic performances at various operating points of the compressor stage but also to pro-vide high performances at off-design conditions. It is believed that the highly loaded bowed stator can advance the design of high-performance compressor.

  8. Bow shock fragmentation driven by a thermal instability in laboratory-astrophysics experiments

    CERN Document Server

    Suzuki-Vidal, F; Ciardi, A; Pickworth, L A; Rodriguez, R; Gil, J M; Espinosa, G; Hartigan, P; Swadling, G F; Skidmore, J; Hall, G N; Bennett, M; Bland, S N; Burdiak, G; de Grouchy, P; Music, J; Suttle, L; Hansen, E; Frank, A

    2015-01-01

    The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counter-streaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame and the experiments are driven over many times the characteristic cooling time-scale. The initially smooth bow shock rapidly develops small-scale non-uniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with...

  9. Global explicit particle-in-cell simulations of the nonstationary bow shock and magnetosphere

    CERN Document Server

    Yang, Zhongwei; Liu, Ying D; Parks, George K; Wang, Rui; Lu, Quanming; Hu, Huidong

    2016-01-01

    We carry out two-dimensional global particle-in-cell simulations of the interaction between the solar wind and a dipole field to study the formation of the bow shock and magnetosphere. A self-reforming bow shock ahead of a dipole field is presented by using relatively high temporal-spatial resolutions. We find that (1) the bow shock and the magnetosphere are formed and reach a quasi-stable state after several ion cyclotron periods, and (2) under the Bz southward solar wind condition the bow shock undergoes a self-reformation for low \\b{eta}i and high MA. Simultaneously, a magnetic reconnection in the magnetotail is found. For high \\b{eta}i and low MA, the shock becomes quasi-stationary, and the magnetotail reconnection disappears. In addition, (3) the magnetopause deflects the magnetosheath plasmas. The sheath particles injected at the quasi-perpendicular region of the bow shock can be convected to downstream of an oblique shock region. A fraction of these sheath particles can leak out from the magnetosheath ...

  10. Unilateral Outer Bow Expanded Cervical Headgear Force System: 3D Analysis Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Allahyar Geramy

    2015-10-01

    Full Text Available Objectives: Headgears are among the effective orthodontic appliances to achieve treatment goals. Unilateral molar distal movement is sometimes needed during an orthodontic treat- ment, which can be achieved by an asymmetric headgear. Different unilateral headgears have been introduced. The main goal of this study was to analyze the force system of uni- lateral expanded outer bow asymmetric headgears by the finite element method (FEM.Materials and Methods: Six 3D finite element models of a mesiodistal slice of the maxilla containing upper first molars, their periodontal ligaments (PDLs, cancellous bone, cortical bone, and a cervical headgear with expanded outer bow attached to maxillary first molars were designed in SolidWorks 2010 and meshed in ANSYS Workbench ver. 12.1. The mod- els were the same except for the degree of outer bow expansion. The outer bow ends were loaded with 2-Newton force. The distal driving force and the net moment were evaluated.Results: A decrease in the distalizing force in the normal side molar from 1.69 N to 1.37 N was shown by increasing the degree of unilateral expansion. At the same time, the force increased from 2.19 N to 2.49 N in the expanded side molar. A net moment increasing from 2.26 N.mm to 4.64 N.mm was also shown.Conclusion: Unilateral outer bow expansion can produce different distalizing forces in mo- lars, which increase by increasing the expansion.

  11. Bow Shocks from Neutron Stars Scaling Laws and HST Observations of the Guitar Nebula

    CERN Document Server

    Chatterjee, S

    2002-01-01

    The interaction of high-velocity neutron stars with the interstellar medium produces bow shock nebulae, where the relativistic neutron star wind is confined by ram pressure. We present multi-wavelength observations of the Guitar Nebula, including narrow-band H-alpha imaging with HST/WFPC2, which resolves the head of the bow shock. The HST observations are used to fit for the inclination of the pulsar velocity vector to the line of sight, and to determine the combination of spindown energy loss, velocity, and ambient density that sets the scale of the bow shock. We find that the velocity vector is most likely in the plane of the sky. We use the Guitar Nebula and other observed neutron star bow shocks to test scaling laws for their size and H-alpha emission, discuss their prevalence, and present criteria for their detectability in targeted searches. The set of H-alpha bow shocks shows remarkable consistency, in spite of the expected variation in ambient densities and orientations. Together, they support the ass...

  12. BOW SHOCK FRAGMENTATION DRIVEN BY A THERMAL INSTABILITY IN LABORATORY ASTROPHYSICS EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki-Vidal, F.; Lebedev, S. V.; Pickworth, L. A.; Swadling, G. F.; Skidmore, J.; Hall, G. N.; Bennett, M.; Bland, S. N.; Burdiak, G.; De Grouchy, P.; Music, J.; Suttle, L. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Ciardi, A. [Sorbonne Universités, UPMC Univ. Paris 6, UMR 8112, LERMA, F-75005, Paris (France); Rodriguez, R.; Gil, J. M.; Espinosa, G. [Departamento de Fisica de la Universidad de Las Palmas de Gran Canaria, E-35017 Las Palmas de Gran Canaria (Spain); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Hansen, E.; Frank, A., E-mail: f.suzuki@imperial.ac.uk [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

    2015-12-20

    The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counterstreaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame, and the experiments are driven over many times the characteristic cooling timescale. The initially smooth bow shock rapidly develops small-scale nonuniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with the radiative packages ABAKO/RAPCAL.

  13. Bow-tie antennas on a dielectric half-space - Theory and experiment

    Science.gov (United States)

    Compton, Richard C.; Mcphedran, Ross C.; Popovic, Zorana; Rebeiz, Gabriel M.; Tong, Peter P.

    1987-01-01

    A new formulation is discussed for the rigous calculation of the radiation pattern of a bow-tie antenna of finite length and infinitesimal thickness, placed on a lossless dielectric substrate. The analysis is based on a representation of the current density on the metal surface of the antenna as a sum of an imposed (quasistatic) term and a set of current modes with unknown amplitudes. Free-space fields that are expressed in terms of continuous spectra of symmetrized plane waves are matched to the current modes using the method of moments. The resulting set of equations are solved for the unknown current amplitudes. The calculations show that for increasing bow length the antenna impedance spirals rapidly to a value predicted by transmission line theory. The theory also shows that the E-plane pattern of a two-wavelength, 60-deg bow-tie antenna is dominated by low-loss current modes propagating at the dielectric wavenumber. As the bow tie narrows, the loss of the modes increases, and the dominant wavenumber tends to the quasi-static value. Pattern measurements made at 94 GHz are shown to agree well with theoretical predictions. Measurements for a long-wire antenna, a linear array of bow-tie elements, and a log-periodic antenna are also presented.

  14. On the role of the bow shock in power of magnetospheric disturbances

    Science.gov (United States)

    Sedykh, P. A.

    2011-11-01

    Bow shock is a powerful transformer of the solar wind kinetic energy into the gas dynamic and electromagnetic energy. Indeed, the magnetic field tangential component and magnetic energy density increase by factors of almost 4 and approximately 15, respectively, at the bow point when the front is crossed. A jump of the magnetic field tangential component at front crossing means that the front carries an electric current. The solar wind kinetic energy partly transforms to gas kinetic and electromagnetic energy when passage through the bow shock front. The transition layer (magnetosheath) can use the part of this energy for accelerating of plasma, but can conversely spend the part its kinetic energy on the electric power generation, which afterwards may be used by the magnetosphere. Thereby, transition layer can be both consumer and generator of electric power depending upon special conditions. The direction of current behind the bow shock front depends on the sign of the IMF Bz-component. It is this current which sets plasma convection in motion. Energetically, this external current is necessary for maintaining convection of plasma in the inhomogeneous system (magnetosphere). The generator at the bow shock front can be a sufficient source of power for supplying energy to substorm processes in the geomagnetosphere.

  15. Flow separation control by using bowed blade in highly loaded turbine cascades

    Institute of Scientific and Technical Information of China (English)

    YAMAMOTO; Atsumasa

    2009-01-01

    Due to the serious flow separations and centralized vortices,there are high secondary losses in highly loaded turbines.It is imperative to find measures to control the flow separation and vortices hence improve the turbine performance.This paper reports our recent progress on flow separation and vor-tices control in highly loaded turbine cascades by using bowed blades.Two sets of highly loaded tur-bine cascades with the turning angles of 113° and 160°,and each with 7 bowed blade angles 0°(straight),±10°,±20° and ±30° were experimentally investigated.Both internal flow field measurement and flow visualization on the blade surfaces were conducted,and the effects of blade bowing on the flow topology,distribution of vorticity and the flow energy loss were discussed.The results show that,for the cascade with the turning angle of 113°,the appropriately positive bow angle could reduce the flow energy loss;whereas for the cascade with the turning angle of 160°,the well selected negative bow angle can give the better aerodynamic performance.

  16. Flow separation control by using bowed blade in highly loaded turbine cascades

    Institute of Scientific and Technical Information of China (English)

    TAN ChunQing; ZHANG HuaLiang; CHEN HaiSheng; DONG XueZhi; ZHAO HongLei; YAMAMOTO Atsumasa

    2009-01-01

    Due to the serious flow separations and centralized vortices, there are high secondary losses in highly loaded turbines. It is imperative to find measures to control the flow separation and vortices hence improve the turbine performance. This paper reports our recent progress on flow separation and vor-tices control in highly loaded turbine cascades by using bowed blades. Two sets of highly loaded tur-bine cascades with the turning angles of 113°and 160°, and each with 7 bowed blade angles 0°(straight),±10°, ±20° and ±30° were experimentally investigated. Both internal flow field measurement and flow visualization on the blade surfaces were conducted, and the effects of blade bowing on the flow topology, distribution of vorticity and the flow energy loss were discussed. The results show that, for the cascade with the turning angle of 113°, the appropriately positive bow angle could reduce the flow energy loss; whereas for the cascade with the turning angle of 160°, the well selected negative bow angle can give the better aerodynamic performance.

  17. Lithology, fault displacement, and origin of secondary calcium carbonate and opaline silica at Trenches 14 and 14D on the Bow Ridge Fault at Exile Hill, Nye County, Nevada

    International Nuclear Information System (INIS)

    Yucca Mountain, a proposed site for a high-level nuclear-waste repository, is located in southern Nevada, 20 km east of Beatty, and adjacent to the southwest comer of the Nevada Test Site (NTS) (fig. 1). Yucca Mountain is located within the Basin and Range province of the western United States. The climate is semiarid, and the flora is transitional between that of the Mojave Desert to the south and the Great Basin Desert to the north. As part of the evaluation, hydrologic conditions, especially water levels, of Yucca Mountain and vicinity during the Quaternary, and especially the past 20,000 years, are being characterized. In 1982, the US Geological Survey, in cooperation with the US Department of Energy (under interagency agreement DE-A104-78ET44802), excavated twenty-six bulldozer and backhoe trenches in the Yucca Mountain region to evaluate the nature and frequency of Quaternary faulting (Swadley and others, 1984). The trenches were oriented perpendicular to traces of suspected Quaternary faults and across projections of known bedrock faults into Quaternary deposits. Trench 14 exposes the Bow Ridge Fault on the west side of Exile Hill. Although the original purpose of the excavation of trench 14 was to evaluate the nature and frequency of Quaternary faulting on the Bow Ridge Fault, concern arose as to whether or not the nearly vertical calcium carbonate (the term ''carbonate'' in this study refers to calcium carbonate) and opaline silica veins in the fault zone were deposited by ascending waters (ground water). These veins resemble in gross morphology veins commonly formed by hydrothermal processes

  18. Acute mountain sickness

    Science.gov (United States)

    High altitude cerebral edema; Altitude anoxia; Altitude sickness; Mountain sickness; High altitude pulmonary edema ... Acute mountain sickness is caused by reduced air pressure and lower oxygen levels at high altitudes. The faster you ...

  19. Transport of Solar Wind H+ and He++ Ions across Earth’s Bow Shock

    Science.gov (United States)

    Parks, G. K.; Lee, E.; Fu, S. Y.; Kim, H. E.; Ma, Y. Q.; Yang, Z. W.; Liu, Y.; Lin, N.; Hong, J.; Canu, P.; Dandouras, I.; Rème, H.; Goldstein, M. L.

    2016-07-01

    We have investigated the dependence of mass, energy, and charge of solar wind (SW) transport across Earth’s bow shock. An examination of 111 crossings during quiet SW in both quasi-perpendicular and quasi-parallel shock regions shows that 64 crossings had various degrees of heating and thermalization of SW. We found 22 crossings where the SW speed was flat top distribution is ∼50 Volts. We find that the temperatures of H+ and He++ beams that penetrate the shock can sometimes be nearly the same in the upstream and downstream regions, indicating little or no heating had occurred crossing the bow shock. None of the models predict that the SW can cross the bow shock without heating. Our observations are important constraints for new models of collisionless shocks.

  20. A matched Bow-tie antenna at 433MHz for use in underwater wireless sensor networks

    International Nuclear Information System (INIS)

    Electromagnetic (EM) wave propagation underwater is been disregarded because of attenuation at high frequencies, however the theory predicts that propagation is possible at some useful distance in the lower Industrial, Scientific and Medical (ISM) band. Common transceivers rely on narrowband antennas and matching circuit. The aim of this paper is to design a broadband 433MHz bow-tie antenna and experiment it in air and water without a matching circuit. This antenna could be attached to wireless transceivers and form a Wireless Sensor Network for deployment in various underwater applications. The bow-tie antennas were designed, simulated and constructed in laboratory. Experiments were setup carefully by using a completely isolated transmitter from electronics to avoid airborne transmission. The 433MHz. bow-tie proved its suitability for use in Underwater.

  1. An Analytical Method for Calculating the Satellite Bow Shock/Magnetopause Interception Positions and Times

    CERN Document Server

    Atanassov, Atanas Marinov

    2010-01-01

    This paper contains a presentation of analytical solution of the problem of calculating the places and moments of intersection of satellite trajectories with elements of the Earth's magnetosphere (bow shock and magnetopause). The satellite motion is presented in a Kepler's approximation. Magnetopause and bow shock are described by second-order surfaces- elliptic paraboloides. These surfaces are employed as situational conditions for determining the points of intersection they have (if any) with the satellite trajectory. The situational condition is herein transformed into the plane of Kepler's orbit, thereafter it is reduced to a second-order plane curve- quadric (ellipse or parabola). The solution of this system, containing the equation of this curve and Kepler's ellipse equation, allows determining the places where orbits intersect with the magnetopause or the bow shock. The solution of this system is suggested to be given by reducing the system to a fourth-order equation.

  2. Prenatal diagnosis of metatropic dysplasia: beware of the pseudo-bowing sign

    Energy Technology Data Exchange (ETDEWEB)

    Garel, Catherine [Trousseau Hospital, University Hospitals of the East of Paris, Department of Radiology, Paris (France); Hopital d' Enfants Armand-Trousseau, Department of Radiology, Paris (France); Dhouib, Amira; Sileo, Chiara; Ducou le Pointe, Hubert [Trousseau Hospital, University Hospitals of the East of Paris, Department of Radiology, Paris (France); Cormier-Daire, Valerie [Paris Descartes University, Sorbonne Paris Cite, Necker-Enfants-Malades Hospital, Department of Genetics, Paris (France)

    2014-03-15

    Metatropic dysplasia is a very rare form of osteochondrodysplasia with only one case of prenatal diagnosis described in the literature. It is characterized by marked shortening of the long bones with severe platyspondyly and dumbbell-shape metaphyses. We report a case of metatropic dysplasia that was diagnosed prenatally and describe the findings on US and CT. The pregnancy was terminated and the post-mortem radiographs are shown. The woman had been referred for short and bowed long bones. Severe metaphyseal enlargement was a misleading finding because it had been misinterpreted as limb bowing. Thus when abnormal curvature of the long bones is observed at prenatal US, attention should be drawn not only to the diaphyses but also to the metaphyses because severe metaphyseal enlargement might be responsible for pseudo-bowing. (orig.)

  3. Numerical Study on the Effect of Buffer Bow Structure in Ship-to-ship Collisions

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Endo, Hisayoshi; Pedersen, Preben Terndrup

    2005-01-01

    A disastrous oil spill from a struck oil tanker has become one of the major problems in view of conservation of maritime environment. So far double hulls (D/H) have been introduced to reduce the consequences of collision and grounding events In order to further reduce the oil spill from struck oil...... a very large crude oil carrier (VLCC) in ballast condition collides with the midship region of a D/H VLCC in a laden condition. Fracture of fillet welds, elastic-plastic material properties and strain rate effects, are taken into account in the simulations. The effect of the equivalent failure strain (FS...... tankers, the introduction of buffer bulbous bows has been proposed. Relatively soft buffer bows absorb part of the kinetic energy of the striking ship before penetrating the inner hull of the struck vessel. The purpose of the present paper is to verify the effectiveness of a prototype buffer bulbous bow...

  4. Transport of Solar Wind H+ and He++ Ions across Earth’s Bow Shock

    Science.gov (United States)

    Parks, G. K.; Lee, E.; Fu, S. Y.; Kim, H. E.; Ma, Y. Q.; Yang, Z. W.; Liu, Y.; Lin, N.; Hong, J.; Canu, P.; Dandouras, I.; Rème, H.; Goldstein, M. L.

    2016-07-01

    We have investigated the dependence of mass, energy, and charge of solar wind (SW) transport across Earth’s bow shock. An examination of 111 crossings during quiet SW in both quasi-perpendicular and quasi-parallel shock regions shows that 64 crossings had various degrees of heating and thermalization of SW. We found 22 crossings where the SW speed was flat top distribution is ˜50 Volts. We find that the temperatures of H+ and He++ beams that penetrate the shock can sometimes be nearly the same in the upstream and downstream regions, indicating little or no heating had occurred crossing the bow shock. None of the models predict that the SW can cross the bow shock without heating. Our observations are important constraints for new models of collisionless shocks.

  5. A numerical study on bow shocks around the lightning return stroke channel

    International Nuclear Information System (INIS)

    Bow shock structures are important to various hydrodynamics and magnetohydrodynamics (MHD) phenomena in geophysics and astrophysics. The formation and propagation of bow shocks around the lightning return stroke channel are investigated based on the self-similar motion theory and simulated with a two-dimensional Eulerian finite volume resistive radiation MHD code. In this framework, as verification of theoretical models, the evolving structures of many quantities, such as the plasma density, temperature, pressure, shock velocity, and magnetic field, can be obtained, which present all the characteristics of bow shocks in the lightning return stroke processes. The evolution characteristics and the configuration of the curved return stroke channels, e.g., the non-ideal effects and the scaling laws, are discussed in detail. The results may have applications for some observed features of the return stroke channels and other phenomena in the lightning discharge plasmas

  6. A numerical study on bow shocks around the lightning return stroke channel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qiang, E-mail: cq0405@126.com; Chen, Bin, E-mail: emcchen@163.com; Yi, Yun [National Key Laboratory of Electromagnetic Environment and Electro-Optical Engineering, PLA University of Science and Technology, Nanjing 210007 (China); Chen, P. F., E-mail: chenpf@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China); Mao, Yunfei [The China Satellite Maritime Tracking and Control Department, Yuan Wang III, Jiangyin 214400 (China); Xiong, Run [Engineer Academy of PLA, Xuzhou 221004 (China)

    2015-03-15

    Bow shock structures are important to various hydrodynamics and magnetohydrodynamics (MHD) phenomena in geophysics and astrophysics. The formation and propagation of bow shocks around the lightning return stroke channel are investigated based on the self-similar motion theory and simulated with a two-dimensional Eulerian finite volume resistive radiation MHD code. In this framework, as verification of theoretical models, the evolving structures of many quantities, such as the plasma density, temperature, pressure, shock velocity, and magnetic field, can be obtained, which present all the characteristics of bow shocks in the lightning return stroke processes. The evolution characteristics and the configuration of the curved return stroke channels, e.g., the non-ideal effects and the scaling laws, are discussed in detail. The results may have applications for some observed features of the return stroke channels and other phenomena in the lightning discharge plasmas.

  7. Bow shock nebulae of hot massive stars in a magnetized medium

    CERN Document Server

    Meyer, D M -A; Kuiper, R; Raga, A; Kley, W

    2016-01-01

    A significant fraction of OB-type, main-sequence massive stars are classified as runaway and move supersonically through the interstellar medium (ISM). Their strong stellar winds interact with their surroundings where the typical strength of the local ISM magnetic field is about 3.5-7 micro-G, which can result in the formation of bow shock nebulae. We investigate the effects of such magnetic fields, aligned with the motion of the flow, on the formation and emission properties of these circumstellar structures. Our axisymmetric, magneto-hydrodynamical simulations with optically-thin radiative cooling, heating and anisotropic thermal conduction show that the presence of the background ISM magnetic field affects the projected optical emission our bow shocks at Ha and [OIII] lambda 5007 which become fainter by about 1-2 orders of magnitude, respectively. Radiative transfer calculations against dust opacity indicate that the magnetic field slightly diminishes their projected infrared emission and that our bow shoc...

  8. Effect of coarse woody debris manipulation on soricid and herpetofaunal communities in upland pine stands of the southeastern coastal plain.

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Justin, Charles

    2009-04-01

    Abstract -The majority of studies investigating the importance of coarse woody debris (CWD) to forest- floor vertebrates have taken place in the Pacific Northwest and southern Appalachian Mountains, while comparative studies in the southeastern Coastal Plain are lacking. My study was a continuation of a long-term project investigating the importance of CWD as a habitat component for shrew and herpetofaunal communities within managed pine stands in the southeastern Coastal Plain. Results suggest that addition of CWD can increase abundance of southeastern and southern short-tailed shrews. However, downed wood does not appear to be a critical habitat component for amphibians and reptiles. Rising petroleum costs and advances in wood utilization technology have resulted in an emerging biofuels market with potential to decrease CWD volumes left in forests following timber harvests. Therefore, forest managers must understand the value of CWD as an ecosystem component to maintain economically productive forests while conserving biological diversity.

  9. Post-Palaeozoic uplift history of southeastern Australia revisited: results from a process-based mode of landscape evolution

    International Nuclear Information System (INIS)

    Developments over the last decade in the debate concerning the geomorphic evolution of the south-eastern Australian highlands are reviewed, taking as a starting point the model of passive denudation and isostatic rebound of a Palaeozoic mountain belt presented by Lambeck and Stephenson (1986). This model has been popular in the geomorphological community because it provides a quantitative framework to explain the very low rates of landscape evolution inferred from most geomorphological studies. The model has, however, also been criticised for its treatment of erosion as being linearly dependent on elevation, as well as for its predictions of regional uplift and denudation patterns that are not in accord with inferences from fission-track thermochronological data. Part of controversy stems from conceptual misunderstandings on the interpretation of data and from insufficient consideration of questions of spatial and temporal scale. First results of a new physical process-based model for large-scale long-term landscape evolution in the south-eastern highlands are presented. These show that the denudation history and drainage development of south-eastern Australia can be explained to a first order without invoking large-scale mid-Cretaceous or Tertiary uplift events. The model predicts drainage patterns in southeastern Australia to have evolved by rearrangement of an initially north-westerly directed drainage net, caused by drops in base-level during Mesozoic rifting along the southern and eastern margins of the study region. The geomorphology and available fission-track data in the Snowy Mountains region (and possibly also in the Bathurst - Blue Mountains region) do require renewed (mid Cretaceous?) uplift to have taken place. The model results are discussed in the light of recent controversies surrounding the southeastern highlands-their uplift history, denudation rates, depth of denudation of the coastal strip and inferred Mesozoic drainage patterns. Copyright (1999

  10. Intervention of laser periphery iridectomy to posterior iris bowing in high myopic eyes

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-tao; WANG Ning-li; LI Shu-ning

    2012-01-01

    Background For some high myopic patients with posterior iris bowing,laser periphery iridectomy should be performed pre-operation to prevent pupil block glaucoma if these patients would have phakic intraocular lens implantation to correct high myopia.So we had the opportunity to analysis the influence of laser iridectomy on posterior iris bowing.Methods Eighteen high myopic patients with posterior iris bowing (11 males and 7 females) were involved in the study in Beijing Tongren Eye Center from March 2008 to July 2008.Phakic intraocular lens were implanted to correct their ametropia.The mean age was (32±6) years (range,25-40 years).The center anterior chamber depth,the pupil diameter,the posterior iris bowing depth and the anterior chamber angle were measured with anterior segment coherence tomography (AS-OCT) under the normal condition,myosis condition induced by 2% pilocarpine,laser periphery iridectomy after myosis,and 2% pilocarpine eluting condition respectively.Results There was no significant difference of center anterior chamber depth under the four conditions (P=0.512).The pupil constricted after pilocarpine (P=0.001).After laser iridectomy performed and pilocarpine eluted,posterior iris bowing depth reduced more than that in normal condition (P=0.003).The anterior chamber angle reduced significantly after laser periphery iridectomy and pilocarpine eluted (P=0.012).Conclusion Laser periphery iridectomy can reduce the posterior iris bowing,which might be due to the change in aqueous circulate pathway.

  11. Asymmetric Outer Bow Length and Cervical Headgear Force System: 3D Analysis Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Allahyar Geramy

    2015-10-01

    Full Text Available Objectives: This study sought to assess distal and lateral forces and moments of asymmetric headgears by variable outer bow lengths.Materials and Methods: Four 3D finite element method (FEM models of a cer- vical headgear attached to the maxillary first molars were designed in SolidWorks2010 software and transferred to ANSYS Workbench ver. 11 software. Modelscontained the first molars, their periodontal ligament (PDL, cancellous and cor- tical bones, a mesiodistal slice of the maxillae and the headgear. Models were the same except for the outer bow length in headgears. The headgear was symmetric in model 1. In models 2 to 4, the headgears were asymmetric in length with dif- ferences of 5mm, 10mm and 15mm, respectively. A 2.5 N force in horizontal plane was applied and the loading manner of each side of the outer bow was cal- culated trigonometrically using data from a volunteer.Results: The 15mm difference in outer bow length caused the greatest difference in lateral (=0.21 N and distal (= 1.008 N forces and also generated moments (5.044 N.mm.Conclusion: As the difference in outer bow length became greater, asymmetric effects increased. Greater distal force in the longer arm side was associated with greater lateral force towards the shorter arm side and more net yawing moment. Clinical Relevance:A difference range of 1mm to 15 mm of length in cervical headgear can be consi-dered as a safe length of outer bow shortening in clinical use.

  12. Accuracy of two face-bow/semi-adjustable articulator systems in transferring the maxillary occlusal cant

    Directory of Open Access Journals (Sweden)

    Nazia Nazir

    2012-01-01

    Full Text Available Context: The precision of an arbitrary face-bow in accurately transferring the orientation of the maxillary cast to the articulator has been questioned because the maxillary cast is mounted in relation to arbitrary measurements and anatomic landmarks that vary among individuals. Aim: This study was intended to evaluate the sagittal inclination of mounted maxillary casts on two semi-adjustable articulator/face-bow systems in comparison to the occlusal cant on lateral cephalograms. Materials and Methods: Maxillary casts were mounted on the Hanau and Girrbach semi-adjustable articulators following face-bow transfer with their respective face-bows. The sagittal inclination of these casts was measured in relation to the fixed horizontal reference plane using physical measurements. Occlusal cant was measured on lateral cephalograms. SPSS software (version 11.0, Chicago, IL, USA was used for statistical analysis. Repeated measures analysis of variance and Tukey′s tests were used to evaluate the results (P < 0.05. Results: Comparison of the occlusal cant on the articulators and cephalogram revealed statistically significant differences. Occlusal plane was steeper on Girrbach Artex articulator in comparison to the Hanau articulator. Conclusion: Within the limitations of this study, it was found that the sagittal inclination of the mounted maxillary cast achieved with Hanau articulator was closer to the cephalometric occlusal cant as compared to that of the Girrbach articulator. Among the two articulators and face-bow systems, the steepness of sagittal inclination was greater on Girrbach semi-adjustable articulator. Different face-bow/articulator systems could result in different orientation of the maxillary cast, resulting in variation in stability, cuspal inclines and cuspal heights.

  13. 77 FR 16028 - Broken Bow Wind, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Science.gov (United States)

    2012-03-19

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

  14. 75 FR 19936 - Medicine Bow-Routt National Forests, Brush Creek/Hayden Ranger District Saratoga, WY

    Science.gov (United States)

    2010-04-16

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Medicine Bow-Routt National Forests, Brush Creek/Hayden Ranger... actions within the Savery Analysis Area of the Brush Creek/Hayden Ranger District of the Medicine Bow-Routt National Forests within Carbon County, Wyoming. Proposed actions include prescribed burning...

  15. Corporate-Feed Multilayer Bow-Tie Antenna Array Design Using a Simple Transmission Line Model

    OpenAIRE

    Didouh, S.; Abri, M.; F. T. Bendimerad

    2012-01-01

    A transmission line model is used to design corporate-fed multilayered bow-tie antennas arrays; the simulated antennas arrays are designed to resonate at the frequencies 2.4 GHz, 5 GHz, and 8 GHz corresponding to RFID, WIFI, and radars applications. The contribution of this paper consists of modeling multilayer bow-tie antenna array fed through an aperture using transmission line model. The transmission line model is simple and precise and allows taking into account the whole geometrical, ele...

  16. Method for evaluating bow tie filter angle-dependent attenuation in CT: Theory and simulation results

    OpenAIRE

    Boone, John M.

    2009-01-01

    Purpose: Dosimetry in computed tomography (CT) is increasingly based on Monte Carlo studies that define the dose in the patient (in mGy) as a function of air kerma (free in air) at isocenter (mGy). The accuracy of Monte Carlo studies depends in part on the accuracy of the characterization of the bow tie filter for a given CT scanner model. A simple method for characterizing the bow tie filter attenuation profile in CT scanners would therefore be very useful. The theory behind such a method is...

  17. Ground-state magnetic phase diagram of bow-tie graphene nanoflakes in external magnetic field

    OpenAIRE

    Szałowski, Karol

    2013-01-01

    The magnetic phase diagram of a ground state is studied theoretically for graphene nanoflakes of bow-tie shape and various size in external in-plane magnetic field. The tight-binding Hamiltonian supplemented with Hubbard term is used to model the electronic structure of the systems in question. The existence of the antiferromagnetic phase with magnetic moments localized at the sides of the bow-tie is found for low field and a field-induced spin-flip transition to ferromagnetic state is predic...

  18. Analysis of Silver Ink Bow-Tie RFID Tag Antennas Printed on Paper Substrates

    OpenAIRE

    Sari Merilampi; Leena Ukkonen; Lauri Sydänheimo; Pekka Ruuskanen; Markku Kivikoski

    2007-01-01

    In this study, polymeric silver inks, paper substrates, and screen printing were used to produce prototype Bow-Tie tags. Because of increasing interest in applying passive UHF-RFID systems in paper industry, the Bow-Tie antenna used in this study was designed to work through paper. The maximum reliable read ranges of the tags were measured thorough stacked paper and also in air. The analysis and functioning of the antenna design are also discussed. All inks and paper substrates were suitable ...

  19. A benchmark study of procedures for analysis of axial crushing of bulbous bows

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Pedersen, Preben Terndrup

    2008-01-01

    Simplified methods to estimate mean axial crushing forces of plated structures are reviewed and applied to a series of experimental results for axial crushing of large-scale bulbous bow models. Methods based on intersection unit elements such as L-, T- and X-type elements as well as methods based...... on plate unit elements are employed in the analyses. The crushing forces and the total absorbed energy obtained by the simplified analyses are compared with those obtained from large-scale bulbous bow experiments. The accuracy and the applicability of these methods are discussed in detail....

  20. Comparison of accelerated ion populations observed upstream of the bow shocks at Venus and Mars

    OpenAIRE

    Yamauchi, M.; Y. Futaana; Fedorov, A.; Frahm, R. A.; Winningham, J. D.; Dubinin, E.; R. Lundin; Barabash, S.; Holmström, M.; Mazelle, C.; Sauvaud, J.-A.; T. L. Zhang; W. Baumjohann; A. J. Coates; Fraenz, M.

    2011-01-01

    Foreshock ions are compared between Venus and Mars at energies of 0.6 similar to 20 keV using the same ion instrument, the Ion Mass Analyser, on board both Venus Express and Mars Express. Venus Express often observes accelerated protons (2 similar to 6 times the solar wind energy) that travel away from the Venus bow shock when the spacecraft location is magnetically connected to the bow shock. The observed ions have a large field-aligned velocity compared to the perpendicular velocity in the ...

  1. Towards a real-time system for teaching novices good violin bowing technique

    OpenAIRE

    van der Linden, Janet; Schoonderwaldt, Erwin; Bird, Jon

    2009-01-01

    We describe the ongoing development of a system to support the teaching of good posture and bowing technique to novice violin players. Using an inertial motion capture system we can track in real-time: i) a player’s bowing action (and measure how it deviates from a target trajectory); ii) whether the player is holding their violin correctly. We detail some initial experiments that show that vibrotactile feedback can guide arm movements in one and two dimensions. We then present some prelimina...

  2. Diversity and composition of Trichoptera (Insecta) larvae assemblages in streams with different environmental conditions at Serra da Bocaina, Southeastern Brazil

    OpenAIRE

    Ana Lucia Henriques-Oliveira; Jorge Luiz Nessimian; Darcílio Fernandes Baptista

    2015-01-01

    Abstract: Aim The goal of this study is to examine the composition and richness of caddisfly assemblages in streams at the Serra da Bocaina Mountains, Southeastern Brazil, and to identify the main environmental variables, affecting caddisfly assemblages at the streams with different conditions of land use. Methods The sampling was conducted in 19 streams during September and October 2007. All sites were characterized physiographically by application of environmental assessment protocol to At...

  3. Cherkis bow varieties and Coulomb branches of quiver gauge theories of affine type $A$

    CERN Document Server

    Nakajima, Hiraku

    2016-01-01

    We show that Coulomb branches of quiver gauge theories of affine type $A$ are Cherkis bow varieties, which have been introduced as ADHM type description of moduli space of instantons on the Taub-NUT space equivariant under a cyclic group action.

  4. X-ray Emission Line Profiles from Wind Clump Bow Shocks in Massive Stars

    CERN Document Server

    Ignace, R; Cassinelli, J P

    2012-01-01

    The consequences of structured flows continue to be a pressing topic in relating spectral data to physical processes occurring in massive star winds. In a preceding paper, our group reported on hydrodynamic simulations of hypersonic flow past a rigid spherical clump to explore the structure of bow shocks that can form around wind clumps. Here we report on profiles of emission lines that arise from such bow shock morphologies. To compute emission line profiles, we adopt a two component flow structure of wind and clumps using two "beta" velocity laws. While individual bow shocks tend to generate double horned emission line profiles, a group of bow shocks can lead to line profiles with a range of shapes with blueshifted peak emission that depends on the degree of X-ray photoabsorption by the interclump wind medium, the number of clump structures in the flow, and the radial distribution of the clumps. Using the two beta law prescription, the theoretical emission measure and temperature distribution throughout the...

  5. Application of the Bow Tie method for evaluation of safety in the procedure of logging wells

    International Nuclear Information System (INIS)

    This work consists of an assessment of security in the practice of logging of oil wells, using the method of Bow Tie for being a simple method of evaluation of the risk, which makes it possible in a structured way to set priorities to manage risk

  6. Fuzzy Bayesian Network-Bow-Tie Analysis of Gas Leakage during Biomass Gasification

    Science.gov (United States)

    Yan, Fang; Xu, Kaili; Yao, Xiwen; Li, Yang

    2016-01-01

    Biomass gasification technology has been rapidly developed recently. But fire and poisoning accidents caused by gas leakage restrict the development and promotion of biomass gasification. Therefore, probabilistic safety assessment (PSA) is necessary for biomass gasification system. Subsequently, Bayesian network-bow-tie (BN-bow-tie) analysis was proposed by mapping bow-tie analysis into Bayesian network (BN). Causes of gas leakage and the accidents triggered by gas leakage can be obtained by bow-tie analysis, and BN was used to confirm the critical nodes of accidents by introducing corresponding three importance measures. Meanwhile, certain occurrence probability of failure was needed in PSA. In view of the insufficient failure data of biomass gasification, the occurrence probability of failure which cannot be obtained from standard reliability data sources was confirmed by fuzzy methods based on expert judgment. An improved approach considered expert weighting to aggregate fuzzy numbers included triangular and trapezoidal numbers was proposed, and the occurrence probability of failure was obtained. Finally, safety measures were indicated based on the obtained critical nodes. The theoretical occurrence probabilities in one year of gas leakage and the accidents caused by it were reduced to 1/10.3 of the original values by these safety measures. PMID:27463975

  7. Beacon: A three-dimensional structural analysis code for bowing history of fast breeder reactor cores

    International Nuclear Information System (INIS)

    The core elements of an LMFBR are bowed due to radial gradients of both temperature and neutron flux in the core. Since all hexagonal elements are multiply supported by adjacent elements or the restraint system, restraint forces and bending stresses are induced. In turn, these forces and stresses are relaxed by irradiation enhanced creep of the material. The analysis of the core bowing behavior requires a three-dimensional consideration of the mechanical interactions among the core elements, because the core consists of different kinds of elements and of fuel assemblies with various burnup histories. A new computational code BEACON has been developed for analyzing the bowing behavior of an LMFBR's core in three dimensions. To evaluate mechanical interactions among core elements, the code uses the analytical method of the earlier SHADOW code. BEACON analyzes the mechanical interactions in three directions, which form angles of 600 with one another. BEACON is applied to the 600 sector of a typical LMFBR's core for analyzing the bowing history during one equilibrium cycle. 120 core elements are treated, assuming the boundary condition of rotational symmetry. The application confirms that the code can be an effective tool for parametric studies as well as for detailed structural analysis of LMFBR's core. (orig.)

  8. 26 CFR 48.4161(b)-1 - Imposition and rates of tax; bows and arrows.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Imposition and rates of tax; bows and arrows. 48.4161(b)-1 Section 48.4161(b)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) MISCELLANEOUS EXCISE TAXES MANUFACTURERS AND RETAILERS EXCISE TAXES Sporting Goods §...

  9. Double-sided printed bow-tie antenna with notch filter for UWB applications

    OpenAIRE

    Hirata, Akimasa; ヒラタ, アキマサ; 平田, 晃正

    2009-01-01

    This letter proposes a double-sided printed bow-tie antenna with a notch band. The notch filter is based on a grounded patch inserted into the feeding microstrip line. The advantage of the structure is its tunability of the notch band.

  10. Fuzzy Bayesian Network-Bow-Tie Analysis of Gas Leakage during Biomass Gasification.

    Directory of Open Access Journals (Sweden)

    Fang Yan

    Full Text Available Biomass gasification technology has been rapidly developed recently. But fire and poisoning accidents caused by gas leakage restrict the development and promotion of biomass gasification. Therefore, probabilistic safety assessment (PSA is necessary for biomass gasification system. Subsequently, Bayesian network-bow-tie (BN-bow-tie analysis was proposed by mapping bow-tie analysis into Bayesian network (BN. Causes of gas leakage and the accidents triggered by gas leakage can be obtained by bow-tie analysis, and BN was used to confirm the critical nodes of accidents by introducing corresponding three importance measures. Meanwhile, certain occurrence probability of failure was needed in PSA. In view of the insufficient failure data of biomass gasification, the occurrence probability of failure which cannot be obtained from standard reliability data sources was confirmed by fuzzy methods based on expert judgment. An improved approach considered expert weighting to aggregate fuzzy numbers included triangular and trapezoidal numbers was proposed, and the occurrence probability of failure was obtained. Finally, safety measures were indicated based on the obtained critical nodes. The theoretical occurrence probabilities in one year of gas leakage and the accidents caused by it were reduced to 1/10.3 of the original values by these safety measures.

  11. Double bow shocks around young, runaway red supergiants: application to Betelgeuse

    CERN Document Server

    Mackey, Jonathan; Neilson, Hilding R; Langer, Norbert; Meyer, Dominique M -A

    2012-01-01

    A significant fraction of massive stars are moving supersonically through the interstellar medium (ISM), either due to disruption of a binary system or ejection from their parent star cluster. The interaction of their wind with the ISM produces a bow shock. In late evolutionary stages these stars may undergo rapid transitions from red to blue and vice versa on the Hertzsprung-Russell diagram, with accompanying rapid changes to their stellar winds and bow shocks. Recent 3D simulations of the bow shock produced by the nearby runaway red supergiant (RSG) Betelgeuse, under the assumption of a constant wind, indicate that the bow shock is very young (<30000 years old), hence Betelgeuse may have only recently become a RSG. To test this possibility, we have calculated stellar evolution models for single stars which match the observed properties of Betelgeuse in the RSG phase. The resulting evolving stellar wind is incorporated into 2D hydrodynamic simulations in which we model a runaway blue supergiant (BSG) as i...

  12. Turbulence at quasi-parallel and quasi-perpendicular bow shocks

    Science.gov (United States)

    Pitna, Alexander; Zastenker, Georgy; Nemecek, Zdenek; Safrankova, Jana

    2016-07-01

    A solar wind is a highly turbulent medium carrying various modes of magnetohydrodynamic and kinetic instabilities. During its supersonic expansion, it meets obstacles like planetary magnetospheres and bow shocks are formed. Depending on the orientation of the ambient magnetic field with respect to the local shock normal, either quasi-parallel or quasi-perpendicular shocks can be formed. Particles reflected at the ramp of the quasi-parallel shock are streaming far upstream along the magnetic field lines, giving rise to all sorts of instabilities like SLAMS and ULF waves. In the case of the quasi-perpendicular bow shock, the reflected particles influence only a narrow upstream region of the order of the proton gyroradius but the downstream plasma becomes highly turbulent regardless of the shock type. We analyze the high cadence (31 ms) data from the BMSW instrument onboard the Spektr-R spacecraft and compare the frequency spectra of observed turbulence in MHD and kinetic ranges in upstream and downstream regions of the supercritical quasi-parallel and quasi-perpendicular bow shocks. We found that the change in the fluctuation level (from upstream to downstream) as well as the spectral indices differ substantially in the MHD and kinetic ranges for both types of bow shock.

  13. Further evidence for a dynamically generated secondary bow in $^{13}$C+$^{12}$C rainbow scattering

    CERN Document Server

    Ohkubo, S; Ogloblin, A A

    2015-01-01

    The existence of a secondary bow is confirmed for 13C+12C nuclear rainbow scattering in addition to the 16O+12C system. This is found by studying the experimental angular distribution of 13C+12C scattering at the incident 13C energy $E_L$=250 MeV with an extended double folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for 12C using a density-dependent nucleon-nucleon force. The Airy minimum at \\theta$ $\\approx$70$^\\circ$, which is not reproduced by a conventional folding potential, is revealed to be a secondary bow generated dynamically by a coupling to the excited state 2+ (4.44 MeV) of 12C. The essential importance of the quadruple {\\it Y2} term (reorientation term) of potential of the excited state 2+ of 12C for the emergence of a secondary bow is found. The mechanism of the secondary bow is intuitively explained by showing how the trajectories are refracted dynamically into the classically forbidden angular region beyond t...

  14. Fuzzy Bayesian Network-Bow-Tie Analysis of Gas Leakage during Biomass Gasification.

    Science.gov (United States)

    Yan, Fang; Xu, Kaili; Yao, Xiwen; Li, Yang

    2016-01-01

    Biomass gasification technology has been rapidly developed recently. But fire and poisoning accidents caused by gas leakage restrict the development and promotion of biomass gasification. Therefore, probabilistic safety assessment (PSA) is necessary for biomass gasification system. Subsequently, Bayesian network-bow-tie (BN-bow-tie) analysis was proposed by mapping bow-tie analysis into Bayesian network (BN). Causes of gas leakage and the accidents triggered by gas leakage can be obtained by bow-tie analysis, and BN was used to confirm the critical nodes of accidents by introducing corresponding three importance measures. Meanwhile, certain occurrence probability of failure was needed in PSA. In view of the insufficient failure data of biomass gasification, the occurrence probability of failure which cannot be obtained from standard reliability data sources was confirmed by fuzzy methods based on expert judgment. An improved approach considered expert weighting to aggregate fuzzy numbers included triangular and trapezoidal numbers was proposed, and the occurrence probability of failure was obtained. Finally, safety measures were indicated based on the obtained critical nodes. The theoretical occurrence probabilities in one year of gas leakage and the accidents caused by it were reduced to 1/10.3 of the original values by these safety measures. PMID:27463975

  15. Beam-Steerable Microstrip-Fed Bow-Tie Antenna Array for Fifth Generation Cellular Communications

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert Frølund

    2016-01-01

    of bow-tie antennas have been used at the top-edge region of mobile phone PCB. The antenna elements fed by microstrip lines are designed to operate at 17 GHz. The simulated results give good performances in terms of different antenna parameters. In addition, an investigation on the distance between...

  16. Observed Foreshock Ions which are Actually Behind the Martian Bow Shock

    Science.gov (United States)

    Frahm, Rudy A.; Yamauchi, Masatoshi; Winningham, J. David; Lundin, Rickard; Sharber, James R.; Nilsson, Hans; Coates, Andrew J.; Mukherjee, Joey

    2016-04-01

    The Mars Express (MEx) Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment contains ion and electron instruments for conducting plasma measurements. On January 23, 2012, during in-bound travel of MEx in the southern hemisphere of Mars traveling from its dawn side toward periapsis at dusk, the plasma instruments measured foreshock-like ion beams extending from outside the bow shock and into the magnetosphere, continuing to a distance of about a proton gyroradius from the bow shock. These ion beams were mostly protons, were observed to have energies greater than solar wind protons, and were not gyrating, in agreement with reflections of the solar wind proton beam. Furthermore, in the foreshock region, the ion energy gradually decreased toward the magnetosheath, in agreement with an acceleration by an outward-directed electric field in the bow shock. The observations also suggest that this electric field exists even inside the magnetosheath, within the distance of a proton gyroradius from the bow shock.

  17. Butterfly Surveys in Southeastern North Dakota : 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The goal of this study was to inventory butterflies and skippers on a number of wetland prairie sites in southeastern North Dakota, and pinpoint the location and...

  18. Butterfly Surveys in Southeastern North Dakota : 1996

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The goal of this study was to inventory butterflies and skippers on a number of wetland prairie sites in southeastern North Dakota, and pinpoint the location and...

  19. Meltwater runoff from Haig Glacier, Canadian Rocky Mountains, 2002–2013

    Directory of Open Access Journals (Sweden)

    S. J. Marshall

    2014-07-01

    Full Text Available Observations of high-elevation meteorological conditions, glacier mass balance, and glacier runoff are sparse in western Canada and the Canadian Rocky Mountains, leading to uncertainty about the importance of glaciers to regional water resources. This needs to be quantified so that the impacts of ongoing glacier recession can be evaluated with respect to alpine ecology, hydroelectric operations, and water resource management. I assess the seasonal evolution of glacier runoff in an alpine watershed on the continental divide in the Canadian Rocky Mountains. Analysis is based on meteorological, snowpack and surface energy balance data collected at Haig Glacier from 2002–2013. The study area is one of several glacierized headwaters catchments of the Bow River, which flows eastward to provide an important supply of water to the Canadian prairies. Annual specific discharge from snow- and ice-melt on Haig Glacier averaged 2350 mm water equivalent (w.e. from 2002–2013, with 42% of the runoff derived from melting of glacier ice and firn, i.e. water stored in the glacier reservoir. This is an order of magnitude greater than the annual specific discharge from non-glacierized parts of the Bow River basin. From 2002–2013, meltwater derived from the glacier storage was equivalent to 5–6% of the flow of the Bow River in Calgary in late summer and 2–3% of annual discharge. The basin is typical of most glacier-fed mountains rivers, where the modest and declining extent of glacierized area in the catchment limits the glacier contribution to annual runoff.

  20. Experimental Investigation of the Effect of Bow Profiles on Resistance of an Underwater Vehicle in Free Surface Motion

    Institute of Scientific and Technical Information of China (English)

    Mehran Javadi; Mojtaba Dehghan Manshadi; Saeid Kheradmand; Mohammad Moonesun

    2015-01-01

    In this paper, towing tank experiments are conducted to study the behavior of flow on a model of the underwater vehicle with various shapes of bows, i.e. tango and standard bows in free surface motion tests. The total resistances for different Froude numbers are considered experimentally. The towing tank is equipped with a trolley that can operate in through 0.05–6 m/s speed with ±0.02 m/s accuracy. Furthermore, the study is done on hydrodynamic coefficients i.e. total, residual and friction resistance coefficients, and the results are compared. Finally, the study on flow of wave fields around bows is done and wave filed around two bows are compared. The Froude number interval is between 0.099 and 0.349. Blockage fraction for the model is fixed to 0.005 3. The results showed that the residual resistance of the standard bow in 0.19 to 0.3 Froude number is more than the tango bow in surface motion which causes more total resistance for the submarine. Finally, details of wave generated by the bow are depicted and the effects of flow pattern on resistance drag are discussed.

  1. Using noble gases to investigate mountain-front recharge

    Science.gov (United States)

    Manning, A.H.; Solomon, D.K.

    2003-01-01

    Mountain-front recharge is a major component of recharge to inter-mountain basin-fill aquifers. The two components of mountain-front recharge are (1) subsurface inflow from the mountain block (subsurface inflow), and (2) infiltration from perennial and ephemeral streams near the mountain front (stream seepage). The magnitude of subsurface inflow is of central importance in source protection planning for basin-fill aquifers and in some water rights disputes, yet existing estimates carry large uncertainties. Stable isotope ratios can indicate the magnitude of mountain-front recharge relative to other components, but are generally incapable of distinguishing subsurface inflow from stream seepage. Noble gases provide an effective tool for determining the relative significance of subsurface inflow, specifically. Dissolved noble gas concentrations allow for the determination of recharge temperature, which is correlated with recharge elevation. The nature of this correlation cannot be assumed, however, and must be derived for the study area. The method is applied to the Salt Lake Valley Principal Aquifer in northern Utah to demonstrate its utility. Samples from 16 springs and mine tunnels in the adjacent Wasatch Mountains indicate that recharge temperature decreases with elevation at about the same rate as the mean annual air temperature, but is on average about 2??C cooler. Samples from 27 valley production wells yield recharge elevations ranging from the valley elevation (about 1500 m) to mid-mountain elevation (about 2500 m). Only six of the wells have recharge elevations less than 1800 m. Recharge elevations consistently greater than 2000 m in the southeastern part of the basin indicate that subsurface inflow constitutes most of the total recharge in this area. ?? 2003 Published by Elsevier Science B.V.

  2. A comparative analysis of 3D flow fields between straight and bowed blades in a steam turbine

    Institute of Scientific and Technical Information of China (English)

    M.HASSANVAND; WANG Zhong-qi 王仲奇; WANG Song-tao 王松涛

    2004-01-01

    A commercial Navier-Stokes flow solver has been employed tor simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stator of a high pressure steam turbine. For comparison, we have studied the effects of bowed blades on the wakes of stator trailing edge and horse shoe vortex in the rotor. It was found that the position of wakes for bowed blades is shifted toward the blade suction side. Also, we have discussed and compared the entropy generation and energy loss caused by dissipation mechanism within the boundary layers on the hub and shroud; and temperature gradient in meridional plane.

  3. Bow shock specularly reflected ions in the presence of low-frequency electromagnetic waves: a case study

    OpenAIRE

    K. Meziane; Mazelle, C.; Wilber, M.; Lequéau, D.; J. P. Eastwood; H. Rème; Dandouras, I.; J. A. Sauvaud; Bosqued, J. M.; Parks, G. K.; Kistler, L. M.; McCarthy, M.; Klecker, B.; Korth, A.; M.-B. Bavassano-Cattaneo

    2004-01-01

    An energetic ion (E≤40) event observed by the CLUSTER/CIS experiment upstream of the Earth's bow shock is studied in detail. The ion event is observed in association with quasi-monochromatic ULF MHD-like waves, which we show modulate the ion fluxes. According to three statistical bow shock position models, the Cluster spacecrafts are located at ~0.5 Re from the shock and the averaged bow shock θ

  4. THE ROLE OF PICKUP IONS ON THE STRUCTURE OF THE VENUSIAN BOW SHOCK AND ITS IMPLICATIONS FOR THE TERMINATION SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Lu Quanming; Shan Lican; Zhang Tielong; Wu Mingyu; Wang Shui [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei 230026 (China); Zank, Gary P. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Yang Zhongwei [SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai (China); Du Aimin, E-mail: qmlu@ustc.edu.cn [Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

    2013-08-20

    The recent crossing of the termination shock by Voyager 2 has demonstrated the important role of pickup ions (PUIs) in the physics of collisionless shocks. The Venus Express (VEX) spacecraft orbits Venus in a 24 hr elliptical orbit that crosses the bow shock twice a day. VEX provides a unique opportunity to investigate the role of PUIs on the structure of collisionless shocks more generally. Using VEX observations, we find that the strength of the Venusian bow shock is weaker when solar activity is strong. We demonstrate that this surprising anti-correlation is due to PUIs mediating the Venusian bow shock.

  5. Mountain Plover [ds109

    Data.gov (United States)

    California Department of Resources — Point locations representing observations of mountain plover (Charadrius montanus) feeding and roosting flocks (and occasional individuals) documented during an...

  6. Assessing habitat quality of the mountain nyala Tragelaphus buxtoni in the Bale Mountains, Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Paul H.EVANGELISTA; John NORMAN Ⅲ; Paul SWARTZINKI; Nicholas E.YOUNG

    2012-01-01

    Populations of the endangered mountain nyala Tragelaphus buxtoni are significantly threatened by the loss of critical habitat.Population estimates are tentative,and information on the species' distribution and available habitat is required for formulating immediate management and conservation strategies.To support management decisions and conservation priorities,we integrated information from a number of small-scale observational studies,interviews and reports from multiple sources to define habitat parameters and create a habitat quality model for mountain nyala in the Bale Mountains.For our analysis,we used the FunConn model,an expertise-based model that considers spatial relationships (i.e,patch size,distance) between the species and vegetation type,topography and disturbance to create a habitat quality surface.The habitat quality model showed that approximately 18,610 km2 (82.7% of our study area) is unsuitable or poor habitat for the mountain nyala,while 2,857 km2 (12.7%) and 1,026 km2 (4.6%) was ranked as good or optimal habitat,respectively.Our results not only reflected human induced habitat degradation,but also revealed an extensive area of intact habitat on the remote slopes of the Bale Mountain's southern and southeastern escarpments.This study provides an example of the roles that expert knowledge can still play in modem geospatial modeling of wildlife habitat.New geospatial tools,such as the FunConn model,are readily available to wildlife managers and allow them to perform spatial analyses with minimal software,data and training requirements.This approach may be especially useful for species that are obscure to science or when field surveys are not practical.

  7. Contributions to the Dart versus Arrow Debate: New Data from Holocene Projectile Points from Southeastern and Southern Brazil

    Directory of Open Access Journals (Sweden)

    Mercedes Okumura

    2015-12-01

    Full Text Available Lithic bifacial points are very common in the southern and southeastern regions of the Brazilian territory. Dated from Early to Late Holocene, these artifacts have not been studied in terms of their propulsion system. Given the characteristics of the bow and arrow compared to the atlatl and dart, there are important differences in the size and weight of arrowheads and dart points. Applying the techniques proposed by Shott (1997, Bradbury (1997, Fenenga (1953, Hughes (1998, and Hildebrandt and King (2012 to specimens recovered from eight sites dating from the early to the late Holocene, this work aims to present preliminary results to better understand the potential presence of darts and arrows in southeastern and southern Brazil. There was a variation in the results according to the application of different techniques. At least one set of points, dated from the Early Holocene, presented quite a high proportion of specimens classified as arrows, indicating the presence of points that could be used as arrowheads.

  8. Half-bow sliding knot: modified suture technique for scleral fixation using the corneoscleral pocket.

    Science.gov (United States)

    Chee, Soon-Phaik

    2011-09-01

    A modified suture technique for precise knot placement in the Hoffman corneoscleral pocket technique of scleral fixation is described. Both loops of the polypropylene suture passing from the intraocular device through the sclera and conjunctiva are retrieved from the pocket. A loop of suture is pulled through 3 suture throws made using the second suture loop, forming a half bow. Centration of the intraocular lens (IOL)-capsular bag is checked. If the suture tension is too tight, the surgeon can easily undo the knot of the half-bow knot by pulling it free and can then retie the sliding knot. When the IOL-capsular bag is centered, the suture loop is cut and the free end removed. The second suture end is retrieved from the pocket, and knot tying is completed without further adjustment to the tension. Posterior pressure on the intraocular device centers it and settles the knot within the sclera at the fixation point.

  9. A Study of Near-Field Radiation Pattern of Bow-Tie Dipole on Ground

    Institute of Scientific and Technical Information of China (English)

    ZHAN Yi; LIANG Changhong; FANG Guangyou; YUAN Hongwei

    2001-01-01

    The study of bow-tie antenna forpulse'radiation in a ground penetrating radar systemis complicated due to the existence of reflections fromthe feed,the far end of the antenna,the air-groundinterface and their interactions.The FDTD methodsare applied in this paper by incorporating a trans-parent source,a bow-tie antenna above the ground,and a lossy soil to investigate the issues.Numeri-cal verifications are conducted to check the accuracyof the method.The radiation properties are demon-strated by near-field radiation patterns and time do-main waveforms at different positions.The influencesdue to different antenna heights and soil parametersare also discussed in detail.

  10. Diagnosis of the Thermal Bow of a Shaft in a Three Stage Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In practice many turbo-machines driven by motors are started up to operational speed within a very short time, i.e. in less than 20 seconds. For this type of machines the compatibility of thermal deformation of the rotor structure must be taken into account in the machine design, or the thermal deformation will be constrained and a huge resultant force can cause the shaft bending and consequently resulting in violent vibrations. In this paper, detection of thermal bow of a shaft in a three stage centrifugal compressor in a petrochemical plant is presented. The diagnostic results show that the thermal bow was induced by the incompatibility of axial thermal deformation of the rotor structure. A remedial action allowing free axial thermal expansion of the outer parts of the rotor is suggested.

  11. Intensity and energy spectrum of electrons accelerated in the earth's bow shock

    Science.gov (United States)

    Anderson, K. A.

    1974-01-01

    Shock waves accelerate charged particles in the solar atmosphere, in interplanetary space and around the earth's magnetosphere. Acceleration of both electrons and protons occurs in the earth's bow-shock. The acceleration of protons up to 100 keV appears to be a steady state process and may even occur upstream from the bow shock due to waves generated by reflected solar wind protons. The electrons, on the other hand, are known to be accelerated in or near the shock. The intensity of these electrons ranges from about 100 to 2,000 per sr-sq cm-sec-keV at 14 keV. The energy spectrum is not a simple power low and is highly variable. If segments of the spectra are fitted to a power low, slopes ranging from -2 to -4.5 result over the energy range 0.5 to 100 keV.

  12. Analysis of Silver Ink Bow-Tie RFID Tag Antennas Printed on Paper Substrates

    Directory of Open Access Journals (Sweden)

    Sari Merilampi

    2007-01-01

    Full Text Available In this study, polymeric silver inks, paper substrates, and screen printing were used to produce prototype Bow-Tie tags. Because of increasing interest in applying passive UHF-RFID systems in paper industry, the Bow-Tie antenna used in this study was designed to work through paper. The maximum reliable read ranges of the tags were measured thorough stacked paper and also in air. The analysis and functioning of the antenna design are also discussed. All inks and paper substrates were suitable as antenna material and the prototype tag antennas had good reading performance. The maximum reliable read ranges were quite the same as for copper and aluminum tags studied elsewhere. This means that printed UHF tags are competitive solutions for the identification of simple mass products.

  13. Highly modular bow-tie gene circuits with programmable dynamic behaviour.

    Science.gov (United States)

    Prochazka, Laura; Angelici, Bartolomeo; Haefliger, Benjamin; Benenson, Yaakov

    2014-01-01

    Synthetic gene circuits often require extensive mutual optimization of their components for successful operation, while modular and programmable design platforms are rare. A possible solution lies in the 'bow-tie' architecture, which stipulates a focal component-a 'knot'-uncoupling circuits' inputs and outputs, simplifying component swapping, and introducing additional layer of control. Here we construct, in cultured human cells, synthetic bow-tie circuits that transduce microRNA inputs into protein outputs with independently programmable logical and dynamic behaviour. The latter is adjusted via two different knot configurations: a transcriptional activator causing the outputs to track input changes reversibly, and a recombinase-based cascade, converting transient inputs into permanent actuation. We characterize the circuits in HEK293 cells, confirming their modularity and scalability, and validate them using endogenous microRNA inputs in additional cell lines. This platform can be used for biotechnological and biomedical applications in vitro, in vivo and potentially in human therapy. PMID:25311543

  14. Comparison of plasma wave measurements in the bow shocks at Earth, Jupiter, Saturn, Uranus and Neptune

    International Nuclear Information System (INIS)

    The authors present plasma wave measurements from the Voyager 2 crossing of Neptune's bow shock and compare them with measurements from the bow shocks of Earth, Jupiter, Saturn and Uranus. The wave amplitudes above 0.01fp, when normalized to the solar wind ion thermal energy density at each planet, are significantly higher at the outer planets than at Earth. Despite the differences in amplitude the shock spectra of all the planets can be fitted to curves of similar form in this frequency range. The total normalized electric field energy densities exhibit an exponential dependence on ion thermal Mach number. Magnetosheath wave energies are comparable at all of the planets when normalized to the downstream plasma pressure

  15. Characterization of Saturn's bow shock: Magnetic field observations of quasi-perpendicular shocks

    CERN Document Server

    Sulaiman, A H; Dougherty, M K

    2016-01-01

    Collisionless shocks vary drastically from terrestrial to astrophysical regimes resulting in radically different characteristics. This poses two complexities. Firstly, separating the influences of these parameters on physical mechanisms such as energy dissipation. Secondly, correlating observations of shock waves over a wide range of each parameter, enough to span across different regimes. Investigating the latter has been restricted since the majority of studies on shocks at exotic regimes (such as supernova remnants) have been achieved either remotely or via simulations, but rarely by means of in-situ observations. Here we present the parameter space of MA bow shock crossings from 2004-2014 as observed by the Cassini spacecraft. We find that Saturn's bow shock exhibits characteristics akin to both terrestrial and astrophysical regimes (MA of order 100), which is principally controlled by the upstream magnetic field strength. Moreover, we determined the {\\theta}Bn of each crossing to show that Saturn's (days...

  16. Comparison of plasma wave measurements in the bow shocks at Earth, Jupiter, Saturn, Uranus and Neptune

    Science.gov (United States)

    Moses, S. L.; Coroniti, F. V.; Kennel, C. F.; Kurth, W. S.; Gurnett, D. A.

    1990-01-01

    Plasma wave measurements from the Voyager 2 crossing of Neptune's bow shock are presented and compared with measurements from the bow shocks of Earth, Jupiter, Saturn, and Uranus. The wave amplitudes above 0.01fp, when normalized to the solar wind ion thermal energy density at each planet, are significantly higher at the outer planets than at Earth. Despite the differences in amplitude, the shock spectra of all the planets can be fitted to curves of similar form in this frequency range. The total normalized electric field energy densities exhibit an exponential dependence on ion thermal Mach number, Magnetosheath wave energies are comparable at all of the planets when normalized to the downstream plasma pressure.

  17. Modelling multi-wavelength observational characteristics of bow shocks from runaway early type stars

    CERN Document Server

    Acreman, David M; Harries, Tim J

    2015-01-01

    We assess the multi-wavelength observable properties of the bow shock around a runaway early type star using a combination of hydrodynamical modelling, radiative transfer calculations and synthetic imaging. Instabilities associated with the forward shock produce dense knots of material which are warm, ionised and contain dust. These knots of material are responsible for the majority of emission at far infra-red, H alpha and radio wavelengths. The large scale bow shock morphology is very similar and differences are primarily due to variations in the assumed spatial resolution. However infra-red intensity slices (at 22 microns and 12 microns) show that the effects of a temperature gradient can be resolved at a realistic spatial resolution for an object at a distance of 1 kpc.

  18. UWB Bi-directional Bow-tie antenna loaded by rings

    Science.gov (United States)

    Peng, Lin; Sun, Kai; Xie, Ji-yang; Qiu, Yu-jie; Jiang, Xing

    2016-07-01

    Performances of bow-tie antennae can be improved by loading a ring. Specially, the distorted radiation patterns of the reference bow-tie antenna (RBA) at high frequencies become less distorted when a ring is added. That is due to the disciplined current flows trained by the ring. Furthermore, when more rings are loaded, which act as reflectors, higher directivities are obtained and, patterns become bi-directional. Antennae with no ring (RBA), one ring, two rings (three cases), three rings, and four rings are investigated. Research find that loading more rings means better directivity. The directivity of the RBA varies from 2.29 dB to 3.66 dB for the frequency band from 2.5 to 7.5 GHz while the directivity for the four-ring-loaded case varies from 4.27 dB to 7.61 dB in that frequency band.

  19. FAILURES AND DEFECTS IN THE BUILDING PROCESS – APPLYING THE BOW-TIE APPROACH

    DEFF Research Database (Denmark)

    Jørgensen, Kirsten

    2009-01-01

    Function failures, defects, mistakes and poor communication are major problems for the construction sector. A Danish research project focusing on failures and defects in building processes has been carried out over the last 2 years. As the empirical element in the research, a large construction...... site was observed from the very start to the very end and all failures and defects of a certain size were recorded and analysed. The methodological approach used in this analysis was the bow-tie model from the area of safety research. It combines critical-event analysis for both causes and effects...... with event-tree analysis. The paper describes this analytical approach as an introduction to a new concept for understanding failures and defects in construction. Analysing the many critical events in the building process with the bow-tie model visualises the complexity of causes. This visualisation offers...

  20. Mapping the Structure of Directed Networks: Beyond the "Bow-tie" Diagram

    OpenAIRE

    Timár, G.; Goltsev, A. V.; Dorogovtsev, S. N.; Mendes, J. F. F.

    2016-01-01

    We reveal a hierarchical organization of finite directed components---tendrils---around the giant components represented by the celebrated "bow-tie" diagram for directed networks. We develop an efficient algorithm to find tendril layers. It is used together with the message passing technique, generalized to directed graphs, to find the structure and attack tolerance of complex networks, such as the World Wide Web, the neural network of Caenorhabditis elegans, and others. We introduce a genera...

  1. [A drill-bow in Horace, Odes 3.6.7].

    Science.gov (United States)

    Moog, Ferdinand Peter

    2004-01-01

    With the short poem Odes 3.26 Horaces says--ostensibly--farewell to the subject of love. A symbol of his retreat is the order given to his followers: they ought to lay in the Temple of Venus the three objects which he has used in his night escapades struggling for the girls' love: lucida funalia (torches), vectis (jemmies), and arcus. The last words has been puzzling the scholars for centuries. Many took offence at the transmitted text and offered conjectures of their own. Some, however, defended arcus using different arguemtns, for instance that arcus refers to bows and arrows as weapons of the lascivious night-reveller. Also the author of this article retains arcus in the text. The context and grammatical construction let assume that also this noun denotes a tool of a burglar, preferably a drill driven by a fiddle-bow. Such instruments were use by carpenters, joiners, and surgeons. Apart from this, gigantic drill-bows were known among military machines. These were frequently applied in sieges. Horace might have seen descriptions and drawings of them in military handbooks which he presumably read in order to prepare himself for his short and rather inglorious career as an officer in the army of Caesar's murderers. For Romans without military experience who suddenly obtained a high rank at war this was a typical way of making good their shortcomings. The parallel between the siege of a town and the attack upon the beloved girl's house must be regarded as a poetic exaggeration; the reader should be amused by an impracticable idea. Furthermore, a possible connection between Horace's poem and the Heracles of Euripides is pointed out here for the first time. In Heracles 942-6 the hero, driven insane by Lyssa's work, asks for his bow, his arrows and siege instruments to take Mycenae, the fortress of his tormentor Eurystheus. In fact he brakes into his own bedroom and kills his spouse and his son.

  2. Deflection Reduction of GaN Wafer Bowing by Coating or Cutting Grooves in the Substrates

    Institute of Scientific and Technical Information of China (English)

    SUN Tao; WANG Ming-Qing; SUN Yong-Jian; WANG Bo-Ping; ZHANG Guo-Yi; TONG Yu-Zhen; DUAN Hui-Ling

    2011-01-01

    @@ GaN films on sapphire substrates are obtained using the metal-organic chemical vapor deposition growth technique.We present two methods to reduce the GaN wafer bowing caused by the mismatch of the thermal expansion coefficients(TECs)between the film and the substrate.The first method is to use coating materials on the back side of the substrate whose TECs are smaller than that of the GaN films.The second is to cut grooves on the back side of the sapphire substrate and filling the grooves with appropriate materials(e.g., tungsten, silicon nitride).For each method, we minimize wafer bowing and even reduce it to zero.Moreover, the two methods can reduce stress concentration and suppress the propagation of cracks in the GaN/sapphire structure.%GaN films on sapphire substrates are obtained using the metal-organic chemical vapor deposition growth technique. We present two methods to reduce the GaN wafer bowing caused by the mismatch of the thermal expansion coefficients (TECs) between the film and the substrate. The first method is to use coating materials on the back side of the substrate whose TECs are smaller than that of the GaN films. The second is to cut grooves on the back side of the sapphire substrate and filling the grooves with appropriate materials (e.g., tungsten, silicon nitride).For each method, we minimize wafer bowing and even reduce it to zero. Moreover, the two methods can reduce stress concentration and suppress the propagation of cracks in the GaN/sapphire structure.

  3. Potts critical frontiers of inhomogeneous and asymmetric bow-tie lattices

    OpenAIRE

    Scullard, Christian R.; Jacobsen, Jesper Lykke

    2012-01-01

    We study the critical frontiers of the Potts model on two-dimensional bow-tie lattices with fully inhomogeneous coupling constants. Generally, for the Potts critical frontier to be found exactly, the underlying lattice must be a 3-uniform hypergraph. A more general class of lattices are the 4-uniform ones, with unit cells contained within four boundary vertices. We demonstrate that in some cases, such lattices can be decomposed into triangular cells, and solved using a modification of standar...

  4. Bow-tie nano-antenna assisted generation of extreme ultraviolet radiation

    OpenAIRE

    Pfullmann, N.; Waltermann, C.; Noack, M.; Rausch, S.; Nagy, T.; Reinhardt, C.; Kovacev, M.; Knittel, V.; Bratschitsch, R.; Akemeier, D.; Huetten, A.; Leitenstorfer, A.; Morgner, Uwe

    2013-01-01

    We report on the generation of extreme ultraviolet radiation utilizing the plasmonic field enhancement in arrays of bow-tie gold optical antennae. Furthermore, their suitability to support high-order harmonic generation is examined by means of finite-difference time-domain calculations and experiments. Particular emphasis is paid to the thermal properties, which become significant at the employed peak intensities. A damage threshold depending on the antenna length is predict...

  5. Self-assembled silver nanoparticles in a bow-tie antenna configuration.

    Science.gov (United States)

    Eskelinen, Antti-Pekka; Moerland, Robert J; Kostiainen, Mauri A; Törmä, Päivi

    2014-03-26

    The self-assembly of silver nanoparticles into a bow-tie antenna configuration is achieved with the DNA origami method. Instead of complicated particle geometries, spherical silver nanoparticles are used. Formation of the structures in high yields is verified with transmission electron microscopy and agarose gel electrophoresis. According to finite-difference time-domain simulations, the antenna configuration could be used as a DNA sensor. PMID:24659271

  6. Bow-tie wobble artifact: Effect of source assembly motion on cone-beam CT

    OpenAIRE

    Zheng, Dandan; John C. Ford; Lu, Jun; Lazos, Dimitrios; Hugo, Geoffrey D.; Pokhrel, Damodar; Zhang, Lisha; Williamson, Jeffrey F.

    2011-01-01

    Purpose: To investigate the cause of a bow-tie wobble artifact (BWA) discovered on Varian OBI CBCT images and to develop practical correction strategies.Method and Materials: The dependence of the BWA on phantom geometry, phantom position, specific system, and reconstruction algorithm was investigated. Simulations were conducted to study the dependence of the BWA on scatter and beam hardening corrections. Geometric calibration was performed to rule out other gantry-angle dependent mechanical ...

  7. Note: auto-relock system for a bow-tie cavity for second harmonic generation.

    Science.gov (United States)

    Haze, Shinsuke; Hata, Sousuke; Fujinaga, Munekazu; Mukaiyama, Takashi

    2013-02-01

    This Note reports on the implementation of an automatic relocking system for a bow-tie cavity for second harmonic generation to produce an ultra-violet laser source. The system is based on a sample-and-hold technique for controlling the cavity length using simple servo electronics. Long-term stabilization of the cavity output power is successfully achieved, which makes this system suitable for designing stable atomic physics experiments. PMID:23464273

  8. The critical manifolds of inhomogeneous bond percolation on bow-tie and checkerboard lattices

    OpenAIRE

    Ziff, Robert M.; Scullard, Christian R.; Wierman, John C.; Sedlock, Matthew R. A.

    2012-01-01

    We give a conditional derivation of the inhomogeneous critical percolation manifold of the bow-tie lattice with five different probabilities, a problem that does not appear at first to fall into any known solvable class. Although our argument is mathematically rigorous only on a region of the manifold, we conjecture that the formula is correct over its entire domain, and we provide a non-rigorous argument for this that employs the negative probability regime of the triangular lattice critical...

  9. Failures and Defects in the Building Process:Applying the Bow-Tie Approach

    OpenAIRE

    Jørgensen, Kirsten

    2009-01-01

    Function failures, defects, mistakes and poor communication are major problems for the construction sector. A Danish research project focusing on failures and defects in building processes has been carried out over the last 2 years. As the empirical element in the research, a large construction site was observed from the very start to the very end and all failures and defects of a certain size were recorded and analysed. The methodological approach used in this analysis was the bow-tie model ...

  10. Variation of the ratio of specific heats across a detached bow shock

    Science.gov (United States)

    Chao, J. K.; Wiskerchen, M. J.

    1974-01-01

    Equations are derived which allow the ratio of specific heats behind the earth's bow shock to be evaluated if several pre-shock parameters (the specific-heat ratio, the Alfvenic Mach number, the sonic Mach number, and the angle between the shock normal at the stagnation point and the magnetic field) and the density jump across the shock are known. Numerical examples show that the dependence of the post-shock ratio on the pre-shock ratio is weak.

  11. Ship Bow Force-Deformation Curves for Ship-Impact Demand of Bridges considering Effect of Pile-Cap Depth

    Directory of Open Access Journals (Sweden)

    Wei Fan

    2014-01-01

    Full Text Available Since static analysis procedures in the vessel impact-resistant design codes neglect dynamic amplification effects related to bridge mass, ship-impact responses of bridges may be potentially underestimated. For this reason, several dynamic vessel-impact analysis techniques had been recently proposed, where a force-deformation curve was employed to model the vessel bow stiffness. Most of the recent works mainly focused on the force-deformation curves of the barge bows rather than the ship bows. In this paper, a high-resolution finite element model is developed to obtain the ship bow force-deformation curves. The global and local characteristics of the ship bow force-deformation curves are discussed based on the finite element crush analyses between the ship bows and the rigid walls. Effect of pile-cap depth on the force-deformation curves (rather than only impact forces is studied in detail, and the corresponding empirical equations are developed using an energy ratio method. Finally, a practical example of ship-bridge collision is investigated to validate the force-deformation curves considering the effect of pile-cap depth. It is found from the case study that the effect of pile-cap depth plays an important role in quantifying structural demand under impact loads. The case study also indicates that the developed equations are reasonable in practical applications.

  12. Southeastern Power Administration 2012 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-01

    Dear Secretary Moniz: I am pleased to submit Southeastern Power Administration’s (Southeastern) fiscal year (FY) 2012 Annual Report for your review. This report reflects our agency’s programs, accomplishments, operational, and financial activities for the 12-month period beginning October 1, 2011, and ending September 30, 2012. This past year, Southeastern marketed approximately 5.4 billion kilowatt-hours of energy to 487 wholesale customers in 10 southeastern states. Revenues from the sale of this power totaled about $263 million. With the financial assistance and support of Southeastern’s customers, funding for capitalized equipment purchases and replacements at hydroelectric facilities operated by the U.S. Army Corps of Engineers (Corps) continued in FY 2012. Currently, there are more than 214 customers participating in funding infrastructure renewal efforts of powerplants feeding the Georgia-Alabama-South Carolina, Kerr-Philpott, and Cumberland Systems. This funding, which totaled more than $71 million, provided much needed repairs and maintenance for aging projects in Southeastern’s marketing area. Drought conditions continued in the southeastern region of the United States this past year, particularly in the Savannah River Basin. Lack of rainfall strained our natural and financial resources. Power purchases for FY 2012 in the Georgia-Alabama-South Carolina System totaled approximately $29 million. About $8 million of this amount was for replacement power, which is purchased only during adverse water conditions in order to meet Southeastern’s customer contract requirements. Southeastern’s goal is to maximize the benefits of our region’s water resources. Competing uses of these resources will present another challenging year for Southeastern’s employees. With the cooperation and communication among the Department of Energy (DOE), preference customers, and Corps, I am certain Southeastern is positioned to meet these challenges in the future. We

  13. Southeastern Power Administration 2011 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2011-12-31

    Dear Secretary Chu: I am pleased to submit Southeastern Power Administration’s (Southeastern) fiscal year (FY) 2011 Annual Report for your review. This report reflects our agency’s programs, accomplishments, operational, and financial activities for the 12-month period beginning October 1, 2010, and ending September 31, 2011. This past year, Southeastern marketed approximately 6.2 billion kilowatt-hours of energy to 489 wholesale customers in 10 southeastern states. Revenues from the sale of this power totaled more than $264 million. With the financial assistance and support of Southeastern’s customers, funding for capitalized equipment purchases and replacements at hydroelectric facilities operated by the U.S. Army Corps of Engineers (Corps) continued in FY 2011. This funding, which totaled more than $45 million, provided much needed repairs and maintenance for aging projects in Southeastern’s marketing area. Currently, there are more than 214 customers participating in the funding efforts in the Georgia-Alabama-South Carolina, Kerr-Philpott, and Cumberland Systems of projects. Drought conditions continued in the southeastern region of the United States this past year, particularly in the Savannah River Basin. Lack of rain placed strains on our natural and financial resources. Power purchases for FY 2011 totaled approximately $38 million. About $9 million of this amount was for replacement power, which is purchased only during adverse water conditions in order to meet Southeastern’s customer contract requirements. Southeastern’s goal is to maximize the benefits of our region’s water resources. Competing uses of these resources will present another challenging year for Southeastern’s employees. With the cooperation and communication among the Department of Energy (DOE), preference customers, and Corps, I am certain Southeastern is positioned to meet these challenges in the future. We are committed to providing reliable hydroelectric power to

  14. Bow-shock instability induced by Helmholtz resonator-like feedback in slipstream

    Science.gov (United States)

    Ohnishi, Naofumi; Sato, Yosuke; Kikuchi, Yuta; Ohtani, Kiyonobu; Yasue, Kanako

    2015-06-01

    Bow-shock instability has been experimentally observed in a low-γ flow. To clarify its mechanism, a parametric study was conducted with three-dimensional numerical simulations for specific heat ratio γ and Mach number M. A critical boundary of the instability was found in the γ-M parametric space. The bow shock tends to be unstable with low γ and high M, and the experimental demonstration was designed based on this result. The experiments were conducted with the ballistic range of the single-stage powder gun mode using HFC-134a of γ = 1.12 at Mach 9.6. Because the deformation of the shock front was observed in a shadowgraph image, the numerical prediction was validated to some extent. The theoretical estimation of vortex formation in a curved shock wave indicates that the generated vorticity is proportional to the density ratio across the shock front and that the critical density ratio can be predicted as ˜10. A strong slipstream from the surface edge generates noticeable acoustic waves because it can be deviated by the upstream flow. The acoustic waves emitted by synchronizing the vortex formation can propagate upstream and may trigger bow-shock instability. This effect should be emphasized in terms of unstable shock formation around an edged flat body.

  15. Numerical Simulation of Star Formation by the Bow Shock of the Centaurus A Jet

    CERN Document Server

    Gardner, Carl L; Scannapieco, Evan; Windhorst, Rogier A

    2016-01-01

    Recent Hubble Space Telescope (HST) observations of the extragalactic radio source Centaurus A (Cen A) display a young stellar population around the southwest tip of the inner filament 8.5 kpc from the Cen A galactic center, with ages in the range of 1-3 Myr. Crockett et al. (2012) argue that the transverse bow shock of the Cen A jet triggered this star formation as it impacted dense molecular cores of clouds in the filament. To test this hypothesis, we perform three-dimensional numerical simulations of induced star formation by the jet bow shock in the inner filament of Cen A, using a positivity preserving WENO method to solve the equations of gas dynamics with radiative cooling. We find that star clusters form inside a bow-shocked molecular cloud when the maximum initial density of the cloud is > 40 H2 molecules/cm^3. In a typical molecular cloud of mass 10^6 M_sun and diameter 200 pc, approximately 20 star clusters of mass 10^3 M_sun are formed, matching the HST images.

  16. AKARI/FIS Mapping of the ISM-Wind Bow Shock around Alpha Ori

    CERN Document Server

    Ueta, Toshiya; Yamamura, Issei; Nakada, Yoshikazu; Matsuura, Mikako; Ita, Yoshifusa; Tanabe, Toshihiko; Fukushi, Hinako; Matsunaga, Noriyuki; Mito, Hiroyuki

    2008-01-01

    We present 10' x 50' scan maps around an M supergiant Alpha Ori at 65, 90, 140 and 160 microns obtained with the AKARI Infrared Astronomy Satellite. Higher spatial resolution data with the exact analytic solution permit us to fit the de-projected shape of the stellar wind bow shock around Alpha Ori to have the stand-off distance of 4.8', position angle of 55 degrees and inclination angle of 56 degrees. The shape of the bow shock suggests that the peculiar velocity of Alpha Ori with respect to the local medium is v_* = 40 (n_H)^(-1/2), where n_H is the hydrogen nucleus density at Alpha Ori. We find that the local medium is of n_H = 1.5 to 1.9 cm^(-3) and the velocity of the local flow is at 11 km s^(-1) by using the most recent astrometric solutions for Alpha Ori under the assumption that the local medium is moving away from the Orion OB 1 association. AKARI images may also reveal a vortex ring due to instabilities on the surface of the bow shock as demonstrated by numerical models. This research exemplifies t...

  17. The propagation and growth of whistler mode waves generated by electron beams in earth's bow shock

    Science.gov (United States)

    Tokar, R. L.; Gurnett, D. A.

    1985-01-01

    In this study, the propagation and growth of whistler mode waves generated by electron beams within earth's bow shock is investigated using a planar model for the bow shock and a model electron distribution function. Within the shock, the model electron distribution function possesses a field-aligned T greater than T beam that is directed toward the magnetosheath. Waves with frequencies between about 1 and 100 Hz with a wide range of wave normal angles are generated by the beam via Landau and anomalous cyclotron resonances. However, because the growth rate is small and because the wave packets traverse the shock quickly, these waves do not attain large amplitudes. Waves with frequencies between about 30 and 150 Hz with a wide range of wave normal angles are generated by the beam via the normal cyclotron resonance. The ray paths for most of these waves are directed toward the solar wind although some wave packets, due to plasma convection travel transverse to the shock normal. These wave packets grow to large amplitudes because they spend a long time in the growth region. The results suggest that whistler mode noise within the shock should increase in amplitude with increasing upstream theta sub Bn. The study provides an explanation for the origin of much of the whistler mode turbulence observed at the bow shock.

  18. Anomalous flow deflection at planetary bow shocks in the low Alfven Mach number regime

    Science.gov (United States)

    Nishino, Masaki N.; Fujimoto, Masaki; Tai, Phan-Duc; Mukai, Toshifumi; Saito, Yoshifumi; Kuznetsova, Masha M.; Rastaetter, Lutz

    A planetary magnetosphere is an obstacle to the super-sonic solar wind and the bow shock is formed in the front-side of it. In ordinary hydro-dynamics, the flow decelerated at the shock is diverted around the obstacle symmetrically about the planet-Sun line, which is indeed observed in the magnetosheath most of the time. Here we show a case under a very low density solar wind in which duskward flow was observed in the dawnside magnetosheath of the Earth's magnetosphere. A Rankine-Hugoniot test across the bow shock shows that the magnetic effect is crucial for this "wrong flow" to appear. A full three-dimensional Magneto- Hydro-Dynamics (MHD) simulation of the situation in this previously unexplored parameter regime is also performed. It is illustrated that in addition to the "wrong flow" feature, various peculiar characteristics appear in the global picture of the MHD flow interaction with the obstacle. The magnetic effect at the bow shock should become more conspicuously around the Mercury's magnetosphere, because stronger interplanetary magnetic field and slower solar wind around the Mercury let the Alfven Mach number low. Resultant strong deformation of the magnetosphere induced by the "wrong flow" will cause more complex interaction between the solar wind and the Mercury.

  19. Origins of bandgap bowing in compound-semiconductor common-cation ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tit, Nacir; Obaidat, Ihab M [Department of Physics, UAE University, PO Box 17551, Al-Ain (United Arab Emirates); Alawadhi, Hussain [Department of Applied Physics, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates)], E-mail: ntit@uaeu.ac.ae

    2009-02-18

    We present an investigation into the existence and origins of bandgap bowing in compound-semiconductor common-cation ternary alloys. As examples, we consider CdSe{sub x}Te{sub 1-x} and ZnSe{sub 1-x}Te{sub x} alloys. A calculation, based on the sp{sup 3}s* tight-binding method including spin-orbit coupling within the framework of the virtual crystal approximation, is employed to determine the bandgap energy, local density of states and atomic charge states versus composition and valence-band offset. The results show that (i) in the valence band, the top states are mainly contributed by Te atoms. The degree of ionicity of all atoms is found to vary linearly with mole fraction x. (ii) There is a strong competition between the anions (Se and Te) in trapping/losing charges and this competition is the main reason for the bandgap bowing character. (iii) There is a reasonable agreement between the calculated results and the available photoluminescence data. (iv) The bowing parameter is found to increase with increasing valence-band offset and increasing lattice mismatch.

  20. Reconstructing the Guitar: Blowing Bubbles with a Pulsar Bow Shock Backflow

    Science.gov (United States)

    van Kerkwijk, Marten H.; Ingle, Ashleigh

    2008-08-01

    The Guitar Nebula is an Hα nebula produced by the interaction of the relativistic wind of a very fast pulsar, PSR B2224+65, with the interstellar medium. It consists of a ram-pressure confined bow shock near its head and a series of semicircular bubbles further behind, the two largest of which form the body of the Guitar. We present a scenario in which this peculiar morphology is due to instabilities in the backflow from the pulsar bow shock. From simulations, these backflows appear similar to jets and their kinetic energy is a large fraction of the total energy in the pulsar's relativistic wind. We suggest that, like jets, these flows become unstable some distance downstream, leading to rapid dissipation of the kinetic energy into heat, and the formation of an expanding bubble. We show that in this scenario the sizes, velocities, and surface brightnesses of the bubbles depend mostly on observables, and that they match roughly what is seen for the Guitar. Similar instabilities may account for features seen in other bow shocks.

  1. Corporate-Feed Multilayer Bow-Tie Antenna Array Design Using a Simple Transmission Line Model

    Directory of Open Access Journals (Sweden)

    S. Didouh

    2012-01-01

    Full Text Available A transmission line model is used to design corporate-fed multilayered bow-tie antennas arrays; the simulated antennas arrays are designed to resonate at the frequencies 2.4 GHz, 5 GHz, and 8 GHz corresponding to RFID, WIFI, and radars applications. The contribution of this paper consists of modeling multilayer bow-tie antenna array fed through an aperture using transmission line model. The transmission line model is simple and precise and allows taking into account the whole geometrical, electrical, and technological characteristics of the antennas arrays. The proposed transmission line model showed its interest in the design of different multilayered bow-tie antennas and predicted the correct resonance frequency for different applications in telecommunications. To validate the proposed transmission line model, the simulation results obtained are compared with those obtained by the method of moments. The results of simulations are presented and discussed. Using this transmission line approach, the resonant frequency, input impedance, and return loss can be determined simultaneously. The paper reports several simulation results that confirm the validity of the developed model. The obtained results are then presented and discussed.

  2. A search for systemic mass loss in Algols with bow shocks

    CERN Document Server

    Mayer, Andreas; Jorissen, Alain

    2016-01-01

    Aims. Various studies indicate that interacting binary stars of Algol type evolve non-conservatively. However, direct detection of systemic mass loss in Algols has been scarce so far. We aim at studying the systemic mass loss in Algols by looking for the presence of infrared excesses originating from the thermal emission of dust grains, which is linked to the presence of a stellar wind. Methods. In contrast to previous studies, we make use of the fact that stellar and interstellar material is piled up at the edge of the asterosphere where the stellar wind interacts with the interstellar medium. We analyse WISE W3 $12\\,\\mu$m and WISE W4 $22\\,\\mu$m data of Algol-type binary Be and B[e] stars and the properties of their bow shocks. From the stand-off distance of the bow shock we are able to determine the mass loss rate of the binary system. Results. Although the velocities of the stars with respect to the interstellar medium are quite low, we find bow shocks to be present in two systems, namely $\\pi$ Aqr, and $\\...

  3. Comparative Study of Electromagnetic Waves at the Bow Shocks of Venus and Earth

    Science.gov (United States)

    Wei, Hanying; Russell, Christopher T.; Strangeway, Robert J.; Schwartz, Steven J.; Zhang, Tielong

    2016-04-01

    Although the solar interactions with Venus and Earth are quite different in many ways, they both have bow shocks formed upstream of the planet where the solar wind decelerates from a super- to sub- magnetosonic flow. In the upstream foreshock region, there is abundant wave activity generated by the shock or by the back-streaming ions and electrons from the shock. In the downstream magnetosheath region, there is also abundant wave activity either locally generated by the heated electrons or ions from the shock or transported from the shock or foreshock regions by the solar wind. The magnetometers of Venus Express and Magnetospheric Multiscale missions both occasionally record 128 Hz data during their shock crossing, which allow us the search for and analyze waves at such high frequencies. We have found short-duration wave bursts around both Venus and Earth bow shocks, with certain similarities. These waves are mostly quasi-perpendicular propagating and have amplitude and occurrence rate decreasing with distance from the bow shock. In this paper we perform statistical and comparative studies on wave properties to understand their generation mechanisms and their effects to the shock or magnetosheath plasmas.

  4. Stable-isotope studies of groundwaters in southeastern New Mexico

    International Nuclear Information System (INIS)

    Oxygen-18/16 and deuterium/hydrogen ratio measurements have been made on groundwaters sampled according to specific field criteria applied during pump tests of the Rustler Formation in Nash Draw, a solution-subsidence valley west of the WIPP site in the northern Delaware Basin of southeastern New Mexico. Comparison of these data with similar measurements on other groundwaters from the northern Delaware Basin indicates two nonoverlapping populations of meteoric groundwaters. Most of the Rustler waters in Nash Draw and at the WIPP site and older waters from the eastern two-thirds of the Capitan Limestone constitute one population, while unconfined groundwaters originating as observable modern surface recharge to alluvium, the near-surface Rustler in southwestern Nash Draw, and the Capitan in the Guadalupe Mountains (Carlsbad Caverns) constitute the other. The isotopic distinction suggests that Rustler groundwater in most of Nash Draw and at the WIPP site is not receiving significant modern meteoric recharge. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. 25 refs., 4 figs., 2 tabs

  5. 75 FR 65624 - Southeastern Power Administration; Notice of Filing

    Science.gov (United States)

    2010-10-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Southeastern Power Administration; Notice of Filing October 19, 2010. Take... Southeastern Power Administration (Southeastern) Rate Order No. SEPA- 53, for the sale of power...

  6. Ephemeroptera, Plecoptera and Trichoptera assemblages in litter in a mountain stream of the Atlantic Rainforest from Southeastern Brazil Comunidades de Ephemeroptera, Plecoptera e Trichoptera em folhiço de um riacho de montanha da Mata Atlântica do Sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    Vera L. Crisci-Bispo

    2007-01-01

    Full Text Available The study of Ephemeroptera, Plecoptera and Trichoptera associated with litter in southeastern Brazil streams aimed to answer the following questions: 1 Does richness and composition of EPT fauna differ between riffle and pool mesohabitats despite being associated to the same substratum, litter? 2 Does the similarity of the EPT fauna between both mesohabitats change with time? 3 Does the EPT functional feeding structure differ between both mesohabitats (riffles-pools? In order to answer these questions, monthly collections, from November 1999 to June 2000, were done in Ribeirão (Stream Bocaina with a D-net (10 litter patches in riffles and 10 in pools. The EPT fauna at Ribeirão Bocaina was more diversified and more abundant in the litter in riffles than in the litter in pools, although, when richness was standardized for the same number of individuals it became similar in both conditions. EPT fauna was very different between both mesohabitats in terms of faunal composition as well as in terms of function. Probably it was due to differences in water speed, in the time of litter residence and in the concentration of dissolved oxygen between both mesohabitats.A fauna de Ephemeroptera, Plecoptera e Trichoptera associadas ao folhiço em um riacho do sudeste do Brasil foi estudada com o objetivo de responder às seguintes questões: 1 A riqueza e a composição faunística de EPT difere entre os dois mesohabitats (corredeira-remanso mesmo quando associadas ao mesmo substrato, folhiço? 2 A similaridade da fauna de EPT entre os dois mesohabitas muda temporalmente? 3 A estrutura funcional de EPT difere entre os dois mesohabitats (corredeira-remanso? Para responder essas questões, coletas mensais, de novembro de 1999 a junho de 2000, foram feitas no Ribeirão Bocaina com rede D (10 acúmulos de folhas em remanso e 10 em corredeira. A fauna de EPT do Ribeirão Bocaina foi mais diversificada e mais abundante no folhiço em corredeira do que no folhi

  7. Measurement of bow tie profiles in CT scanners using a real-time dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Whiting, Bruce R., E-mail: whitingbrucer@gmail.com [Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 (United States); Evans, Joshua D.; Williamson, Jeffrey F. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Dohatcu, Andreea C. [University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213 (United States); Politte, David G. [Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63110 (United States)

    2014-10-15

    Purpose: Several areas of computed tomography (CT) research require knowledge about the intensity profile of the x-ray fan beam that is introduced by a bow tie filter. This information is considered proprietary by CT manufacturers, so noninvasive measurement methods are required. One method using real-time dosimeters has been proposed in the literature. A commercially available dosimeter was used to apply that method, and analysis techniques were developed to extract fan beam profiles from measurements. Methods: A real-time ion chamber was placed near the periphery of an empty CT gantry and the dose rate versus time waveform was recorded as the x-ray source rotated about the isocenter. In contrast to previously proposed analysis methods that assumed a pointlike detector, the finite-size ion chamber received varying amounts of coverage by the collimated x-ray beam during rotation, precluding a simple relationship between the source intensity as a function of fan beam angle and measured intensity. A two-parameter model for measurement intensity was developed that included both effective collimation width and source-to-detector distance, which then was iteratively solved to minimize the error between duplicate measurements at corresponding fan beam angles, allowing determination of the fan beam profile from measured dose-rate waveforms. Measurements were performed on five different scanner systems while varying parameters such as collimation, kVp, and bow tie filters. On one system, direct measurements of the bow tie profile were collected for comparison with the real-time dosimeter technique. Results: The data analysis method for a finite-size detector was found to produce a fan beam profile estimate with a relative error between duplicate measurement intensities of <5%. It was robust over a wide range of collimation widths (e.g., 1–40 mm), producing fan beam profiles that agreed with a relative error of 1%–5%. Comparison with a direct measurement technique on

  8. Synoptic Variability of Extreme Snowfall in the St. Elias Mountains, Yukon, Canada

    OpenAIRE

    Andin, Caroline

    2015-01-01

    Glaciers of southwestern Yukon (Canada) and southeastern Alaska (USA) are presently experiencing high rates of annual mass loss. These high melt rates have mainly been investigated with respect to regional temperature trends, but comparatively little is known about how climate variations regulate snow accumulation on these glaciers. This study examines the synoptic weather patterns and air flow trajectories associated with extreme snowfall events in the central St. Elias Mountains (Yukon). Th...

  9. Assessing habitat quality of the mountain nyala Tragelaphus buxtoni in the Bale Mountains, Ethiopia

    Directory of Open Access Journals (Sweden)

    Paul H. EVANGELISTA, John NORMAN III, Paul SWARTZINKI, Nicholas E. YOUNG

    2012-08-01

    Full Text Available Populations of the endangered mountain nyala Tragelaphus buxtoni are significantly threatened by the loss of critical habitat. Population estimates are tentative, and information on the species’ distribution and available habitat is required for formulating immediate management and conservation strategies. To support management decisions and conservation priorities, we integrated information from a number of small-scale observational studies, interviews and reports from multiple sources to define habitat parameters and create a habitat quality model for mountain nyala in the Bale Mountains. For our analysis, we used the FunConn model, an expertise-based model that considers spatial relationships (i.e., patch size, distance between the species and vegetation type, topography and disturbance to create a habitat quality surface. The habitat quality model showed that approximately 18,610 km2 (82.7% of our study area is unsuitable or poor habitat for the mountain nyala, while 2,857 km2 (12.7% and 1,026 km2 (4.6% was ranked as good or optimal habitat, respectively. Our results not only reflected human induced habitat degradation, but also revealed an extensive area of intact habitat on the remote slopes of the Bale Mountain’s southern and southeastern escarpments. This study provides an example of the roles that expert knowledge can still play in modern geospatial modeling of wildlife habitat. New geospatial tools, such as the FunConn model, are readily available to wildlife managers and allow them to perform spatial analyses with minimal software, data and training requirements. This approach may be especially useful for species that are obscure to science or when field surveys are not practical [Current Zoology 58 (4: 525–535, 2012].

  10. Southeastern Library Network (SOLINET) General Information.

    Science.gov (United States)

    Southeastern Library Network, Inc., Atlanta, GA.

    The computer and telecommunications services of the Southeastern Library Network (SOLINET) are specified in this introduction to the Network. Since members of SOLINET may participate in the services of the Ohio College Library Center (OCLC), a description of these services is included. Membership requirements, fees and dues, and charges to SOLINET…

  11. Emerging Energy Alternatives for the Southeastern States

    Science.gov (United States)

    Stefanakos, E. K. (Editor)

    1978-01-01

    The proceedings of the first symposium on emerging energy alternatives for the Southeastern States are presented. Some topics discussed are: (1) solar energy, (2) wood energy, (3) novel energy sources, (4) agricultural and industrial process heat, (5) waste utilization, (6) energy conservation and (7) ocean thermal energy conversion.

  12. Recreational mountain biking injuries.

    Science.gov (United States)

    Aitken, S A; Biant, L C; Court-Brown, Charles M

    2011-04-01

    Mountain biking is increasing in popularity worldwide. The injury patterns associated with elite level and competitive mountain biking are known. This study analysed the incidence, spectrum and risk factors for injuries sustained during recreational mountain biking. The injury rate was 1.54 injuries per 1000 biker exposures. Men were more commonly injured than women, with those aged 30-39 years at highest risk. The commonest types of injury were wounding, skeletal fracture and musculoskeletal soft tissue injury. Joint dislocations occurred more commonly in older mountain bikers. The limbs were more commonly injured than the axial skeleton. The highest hospital admission rates were observed with head, neck and torso injuries. Protective body armour, clip-in pedals and the use of a full-suspension bicycle may confer a protective effect. PMID:20659880

  13. Mountain-Top Science

    Science.gov (United States)

    Cussen, John P.

    1976-01-01

    Described is the Talcott Mountain Science Center for Student Involvement, Inc., near Hartford, Connecticut, and the programs in natural science offered at the facility and by center personnel in local schools. (SL)

  14. Rocky Mountain spotted fever

    Science.gov (United States)

    ... Mountain spotted fever is caused by the bacteria Rickettsia rickettsii (R. Rickettsii) , which is carried by ticks. ... Saunders; 2014:chap 212. Walker DH, Blaton LS. Rickettsia rickettsii and other spotted fever group rickettsiae (Rocky ...

  15. Diurnal variation of mountain waves

    Directory of Open Access Journals (Sweden)

    R. M. Worthington

    2006-11-01

    Full Text Available Mountain waves could be modified as the boundary layer varies between stable and convective. However case studies show mountain waves day and night, and above e.g. convective rolls with precipitation lines over mountains. VHF radar measurements of vertical wind (1990–2006 confirm a seasonal variation of mountain-wave amplitude, yet there is little diurnal variation of amplitude. Mountain-wave azimuth shows possible diurnal variation compared to wind rotation across the boundary layer.

  16. YUCCA MOUNTAIN SITE DESCRIPTION

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Simmons

    2004-04-16

    The ''Yucca Mountain Site Description'' summarizes, in a single document, the current state of knowledge and understanding of the natural system at Yucca Mountain. It describes the geology; geochemistry; past, present, and projected future climate; regional hydrologic system; and flow and transport within the unsaturated and saturated zones at the site. In addition, it discusses factors affecting radionuclide transport, the effect of thermal loading on the natural system, and tectonic hazards. The ''Yucca Mountain Site Description'' is broad in nature. It summarizes investigations carried out as part of the Yucca Mountain Project since 1988, but it also includes work done at the site in earlier years, as well as studies performed by others. The document has been prepared under the Office of Civilian Radioactive Waste Management quality assurance program for the Yucca Mountain Project. Yucca Mountain is located in Nye County in southern Nevada. The site lies in the north-central part of the Basin and Range physiographic province, within the northernmost subprovince commonly referred to as the Great Basin. The basin and range physiography reflects the extensional tectonic regime that has affected the region during the middle and late Cenozoic Era. Yucca Mountain was initially selected for characterization, in part, because of its thick unsaturated zone, its arid to semiarid climate, and the existence of a rock type that would support excavation of stable openings. In 1987, the United States Congress directed that Yucca Mountain be the only site characterized to evaluate its suitability for development of a geologic repository for high-level radioactive waste and spent nuclear fuel.

  17. YUCCA MOUNTAIN SITE DESCRIPTION

    International Nuclear Information System (INIS)

    The ''Yucca Mountain Site Description'' summarizes, in a single document, the current state of knowledge and understanding of the natural system at Yucca Mountain. It describes the geology; geochemistry; past, present, and projected future climate; regional hydrologic system; and flow and transport within the unsaturated and saturated zones at the site. In addition, it discusses factors affecting radionuclide transport, the effect of thermal loading on the natural system, and tectonic hazards. The ''Yucca Mountain Site Description'' is broad in nature. It summarizes investigations carried out as part of the Yucca Mountain Project since 1988, but it also includes work done at the site in earlier years, as well as studies performed by others. The document has been prepared under the Office of Civilian Radioactive Waste Management quality assurance program for the Yucca Mountain Project. Yucca Mountain is located in Nye County in southern Nevada. The site lies in the north-central part of the Basin and Range physiographic province, within the northernmost subprovince commonly referred to as the Great Basin. The basin and range physiography reflects the extensional tectonic regime that has affected the region during the middle and late Cenozoic Era. Yucca Mountain was initially selected for characterization, in part, because of its thick unsaturated zone, its arid to semiarid climate, and the existence of a rock type that would support excavation of stable openings. In 1987, the United States Congress directed that Yucca Mountain be the only site characterized to evaluate its suitability for development of a geologic repository for high-level radioactive waste and spent nuclear fuel

  18. Southeastern Power Administration 2008 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-29

    Dear Secretary Chu: I am pleased to submit Southeastern Power Administration’s (Southeastern’s) fiscal year (FY) 2008 Annual Report for your review. The information included in this document reflects our agency’s programs, accomplishments, operational and financial activities for the 12-month period beginning October 1, 2007 and ending September 30, 2008. Southeastern marketed more than 4.5 billion kilowatt-hours of energy to 491 wholesale customers in ten southeastern states this past year. Revenues from the sale of this power totaled approximately $263 million. Drought conditions persisted in the southeastern region of the United States during FY 2008 placing strains on our natural and financial resources. Power purchases for FY 2008 totaled $91 million. Approximately $44 million of this amount was for replacement power which is paid only during adverse water conditions in order to meet our customers’ contract requirements. With the continued financial assistance and support of our Federal power customers, funding for capitalized equipment purchases and replacements at U.S. Army Corps of Engineers’ (Corps) hydroelectric projects provided much needed repairs and maintenance for these aging facilities. Southeastern’s cyber and physical security programs continued to be reviewed and updated to meet Department of Energy (DOE), Homeland Security, and North American Electric Reliability Corporation (NERC) standards and requirements. In the coming year, Southeastern will continue open communication and cooperation with DOE, the Federal power customers, and the Corps to maximize the benefits of our region’s water resources. Although competing uses of water and the prolonged drought conditions will present another challenging year for our agency, Southeastern’s employees will meet these challenges and continue to provide reliable hydroelectric power to the people in the southeast. Sincerely, Kenneth E.Legg Administrator

  19. Effect of bow-type initial imperfection on the buckling load and mass of graphite-epoxy blade-stiffened panels

    Science.gov (United States)

    Stroud, W. J.; Anderson, M. S.; Hennessy, K. W.

    1977-01-01

    A structural synthesis computer code which accounts for first order effects of an initial bow and which can be used for sizing stiffened composite panels having an arbitrary cross section is used to study graphite blade-stiffened panels. The effect of a small initial bow on both the load carrying ability of panels and on the mass of panels designed to carry a specified load is examined. Large reductions in the buckling load caused by a small initial bow emphasize the need for considering a bow when a panel is designed.

  20. Social-value maps for Arapaho, Roosevelt, Medicine Bow, Routt, and White River National Forests, Colorado and Wyoming

    Science.gov (United States)

    Ancona, Zachary H.; Semmens, Darius J.; Sherrouse, Benson C.

    2016-03-25

    Executive SummaryThe continued pressures of population growth on the life-sustaining, economic, and cultural ecosystem services provided by our national forests, particularly those located near rapidly growing urban areas, present ongoing challenges to forest managers. Achieving an effective assessment of these ecosystem services includes a proper accounting of the ecological, economic, and social values attributable to them. However, assessments of ecosystem goods and services notably lack information describing the spatial distribution and relative intensity of social values—the perceived, nonmarket values derived particularly from cultural ecosystem services. A geographic information system (GIS) tool developed to fill this need, Social Values for Ecosystem Services (SolVES; http://solves.cr.usgs.gov), now provides the capability to generate social-value maps at a range of spatial scales. This report presents some of the methods behind SolVES, procedures needed to apply the tool, the first formal map products resulting from its application at a regional scale, and a discussion of the management implications associated with this type of information.In this study, we use SolVES to identify the location and relative intensity of social values as derived from survey responses gathered from residents living in counties adjacent to Arapaho, Roosevelt, Medicine Bow, Routt, and White River National Forests. The results, presented as a series of social-value maps, represent the first publicly available spatial data on social-value intensity for the southern Rocky Mountain region. Our analysis identified high-value areas for social values including aesthetic, biodiversity, and life sustaining within wilderness areas. Other values, like recreation, show high-value areas both within wilderness and throughout the general forest areas, which can be attributed to people using the forests for a diverse set of recreational activities. The economic social-value type was lower

  1. Macroscopic polarization and bowing constant of Al{sub x}Ga{sub 1−x}N

    Energy Technology Data Exchange (ETDEWEB)

    Pansari, A.; Gedam, V.; Sahoo, B.K., E-mail: bksahoo.phy@nitrr.ac.in

    2015-01-01

    In this work, we have theoretically investigated the effect of macroscopic polarization (sum of spontaneous and piezoelectric polarization) on various thermal parameters of Al{sub x}Ga{sub 1−x}N alloy. The macroscopic polarization contributes to the effective elastic constant of Al{sub x}Ga{sub 1−x}N alloy. This contribution modifies the phonon group velocity, Debye temperature and Debye frequency of the alloy. The revised values of these thermal parameters have been estimated as a function of Al composition. Our calculation shows that these thermal parameters are enhanced and vary non-linearly with Al composition i.e., they show bowing. The cause of this bowing is the non linear dependence of spontaneous and piezoelectric polarization on Al composition. The bowing constant of above thermal parameters (with and without polarization) has been theoretically predicted by method of best fit. The results show that polarization mechanism not only enhances the parameters but also contribute significantly to bowing constant. The macroscopic polarization contributes around 48% to bowing constant of above thermal parameters. The obtained result will be useful for simulation of nitride optoelectronics devices to predict the effect of polarization mechanism on thermoelectric properties of Al{sub x}Ga{sub 1−x}N alloy.

  2. Effect of an isotropic outflow from the Galactic centre on the bow-shock evolution along the orbit

    CERN Document Server

    Zajacek, Michal; Karas, Vladimir; Kunneriath, Devaky; Shahzamanian, Banafsheh; Sabha, Nadeen; Muzic, Koraljka; Valencia-Schneider, Monica

    2015-01-01

    Motivated by the observations of several infrared-excess bow-shock sources and proplyd-like objects near the Galactic centre, we analyse the effect of a potential outflow from the centre on bow shock properties. We show that due to the non-negligible isotropic central outflow the bow-shock evolution along the orbit becomes asymmetric between the pre-peribothron and post-peribothron phases. This is demonstrated by the calculation of the bow-shock size evolution, the velocity along the shocked layer, the surface density of the bow-shock, and by emission-measure maps close to the peribothron passage. Within the ambient velocity range of $\\lesssim 2000\\,{\\rm km\\, s^{-1}}$ the asymmetry is profound and the changes are considerable for different outflow velocities. As a case study we perform model calculations for the Dusty S-cluster Object (DSO/G2) as a potential young stellar object that is currently being monitored and has passed the pericentre at $\\sim 2000$ Schwarzschild radii from the supermassive black hole ...

  3. Statistical analysis of diffuse ion events upstream of the Earth's bow shock

    Science.gov (United States)

    Trattner, K. J.; Mobius, E.; Scholer, M.; Klecker, B.; Hilchenbach, M.; Luehr, H.

    1994-01-01

    A statistical study of diffuse energetic ion events and their related waves upstream of the Earth's bow shock was performed using data from the Active Magnetospheric Particle Tracer Explorers/Ion Release Module (AMPTE/IRM) satellite over two 5-month periods in 1984 and 1985. The data set was used to test the assumption in the self-consistent model of the upstream wave and particle populations by Lee (1982) that the particle acceleration through hydromagnetic waves and the wave generation are directly coupled. The comparison between the observed wave power and the wave power predicted on the observed energetic particle energy density and solar wind parameters results in a high correlation coefficient of about 0.89. The intensity of diffuse ions falls off approximately exponentially with the distance upstream from the bow shock parallel to the magnetic field with e-folding distances which vary from approximately 3.3 R(sub E) to approximately 11.7 R(sub E) over the energy range from 10 keV/e to 67.3 keV/e for both protons and alpha particles. After normalizing the upstream particle densities to zero bow shock distance by using these exponential variations, a good correlation (0.7) of the density of the diffuse ions with the solar wind density was found. This supports the suggestion that the solar wind is the source of the diffuse ions. Furthermore, the spectral slope of the diffuse ions correlates well with the solar wind velocity component in the direction of the interplanetary magnetic field (0.68 and 0.66 for protons and alpha particles) which concurs with the notion that the solar wind plays an important role in the acceleration of the upstream particles.

  4. GYROSURFING ACCELERATION OF IONS IN FRONT OF EARTH's QUASI-PARALLEL BOW SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Kis, Arpad; Lemperger, Istvan; Wesztergom, Viktor [Research Centre for Astronomy and Earth Sciences, Geodetic and Geophysical Institute, Sopron (Hungary); Agapitov, Oleksiy; Krasnoselskikh, Vladimir [LPC2E/CNRS, F-45071 Orleans (France); Khotyaintsev, Yuri V. [Swedish Institute of Space Physics, SE- 751 21 Uppsala (Sweden); Dandouras, Iannis, E-mail: akis@ggki.hu, E-mail: Kis.Arpad@csfk.mta.hu [CESR, F-31028 Toulouse (France)

    2013-07-01

    It is well known that shocks in space plasmas can accelerate particles to high energies. However, many details of the shock acceleration mechanism are still unknown. A critical element of shock acceleration is the injection problem; i.e., the presence of the so called seed particle population that is needed for the acceleration to work efficiently. In our case study, we present for the first time observational evidence of gyroresonant surfing acceleration in front of Earth's quasi-parallel bow shock resulting in the appearance of the long-suspected seed particle population. For our analysis, we use simultaneous multi-spacecraft measurements provided by the Cluster spacecraft ion (CIS), magnetic (FGM), and electric field and wave instrument (EFW) during a time period of large inter-spacecraft separation distance. The spacecraft were moving toward the bow shock and were situated in the foreshock region. The results show that the gyroresonance surfing acceleration takes place as a consequence of interaction between circularly polarized monochromatic (or quasi-monochromatic) transversal electromagnetic plasma waves and short large amplitude magnetic structures (SLAMSs). The magnetic mirror force of the SLAMS provides the resonant conditions for the ions trapped by the waves and results in the acceleration of ions. Since wave packets with circular polarization and different kinds of magnetic structures are very commonly observed in front of Earth's quasi-parallel bow shock, the gyroresonant surfing acceleration proves to be an important particle injection mechanism. We also show that seed ions are accelerated directly from the solar wind ion population.

  5. Study of the Combination of FTA, ETA and Bow-tie Evaluation Methods and Its Application%基于FTA、ETA、Bow-tie三种评价方法的结合及其应用研究

    Institute of Scientific and Technical Information of China (English)

    李婷婷; 赵姚峰

    2013-01-01

    在FTA与ETA分析方法结合的基础上引入蝴蝶结分析法(Bow-tie法)能很好的克服FTA和ETA的局限性。本文将ETA、FTA及Bow-tie法进行结合并将其应用到燃气管道泄漏的安全评价及分析中。%Introducing Bow-tie analytical method into the combination of FTA and ETA can well overcome the limitation of FTA and ETA. This article combines ETA, FTA and Bon-tie method and apply it into the safety evaluation and analysis of gas pipeline leakage.

  6. Determination of main rational biomechanical characteristics in shooting from a bow

    OpenAIRE

    Adashevskiy V.M.; Iermakov S.S.; Shabashov V.A.

    2012-01-01

    The aim is to build rational parameters of technical actions of sportsman in shooting from a bow. It is worked out and decided mathematical model and the task of dynamics. Influence on having a special purpose exactness of corners of flight of arrow with an account and without the account of force of resistance of air environment is certain. It is distinguished the basic technical run-time errors of sportsman exercises. It is set that for successful realization of descriptions of target exact...

  7. Bi-Band Bow-Tie Antennas Array Design Using a Simple Equivalent Transmission Line Model

    Directory of Open Access Journals (Sweden)

    M. Abri

    2012-08-01

    Full Text Available In this paper we propose a simple equivalent and accurate transmission line model for bi-band bow-tie antennas array design over a band of frequencies for satellite communications. This model uses the resistance of a square element that appears at the edges of the antenna (radiating slots. To test this model, two antennas array were simulated and results were compared with those obtained by a rigorous method (moment’s method of the simulator ADS/Momentum. Using this transmission line approach the resonant frequency, return loss, VSWR, reflected phase, input impedance can be determined simultaneously. The results confirm the validity of the proposed model.

  8. Near-field enhanced ultraviolet resonance Raman spectroscopy using aluminum bow-tie nano-antenna.

    Science.gov (United States)

    Li, Ling; Fang Lim, Shuang; Puretzky, Alexander A; Riehn, Robert; Hallen, H D

    2012-09-10

    An aluminum bow-tie nano-antenna is combined with the resonance Raman effect in the deep ultraviolet to dramatically increase the sensitivity of Raman spectra to a small volume of material, such as benzene used here. We further demonstrate gradient-field Raman peaks for several strong infrared modes. We achieve a gain of [Formula: see text] in signal intensity from the near field enhancement due to the surface plasmon resonance in the aluminum nanostructure. The on-line resonance enhancement contributes another factor of several thousands, limited by the laser line width. Thus, an overall gain of hundreds of million is achieved. PMID:23066168

  9. Bi-Band Bow-Tie Antennas Array Design Using a Simple Equivalent Transmission Line Model

    OpenAIRE

    Abri, M.; H. Abri Badaoui; Dib, H; A.S.E. Gharnaout

    2012-01-01

    In this paper we propose a simple equivalent and accurate transmission line model for bi-band bow-tie antennas array design over a band of frequencies for satellite communications. This model uses the resistance of a square element that appears at the edges of the antenna (radiating slots). To test this model, two antennas array were simulated and results were compared with those obtained by a rigorous method (moment’s method) of the simulator ADS/Momentum. Using this transmission line appro...

  10. Near-field enhanced ultraviolet resonance Raman spectroscopy using aluminum bow-tie nano-antenna

    OpenAIRE

    Li, Ling; Fang Lim, Shuang; Puretzky, Alexander A.; Riehn, Robert; Hallen, H. D.

    2012-01-01

    An aluminum bow-tie nano-antenna is combined with the resonance Raman effect in the deep ultraviolet to dramatically increase the sensitivity of Raman spectra to a small volume of material, such as benzene used here. We further demonstrate gradient-field Raman peaks for several strong infrared modes. We achieve a gain of ∼105 in signal intensity from the near field enhancement due to the surface plasmon resonance in the aluminum nanostructure. The on-line resonance enhancement contributes ano...

  11. Liquid Crystal Bow-Tie Microstrip antenna for Wireless Communication Applications

    Directory of Open Access Journals (Sweden)

    B.T.P.Madhav

    2014-06-01

    Full Text Available In this paper we presented the design and analysis of Bow-Tie antenna on liquid crystal substrate, which is suitable for the Bluetooth/WLAN-2.4/WiBree/ZigBee applications. The Omni-directional radiation patterns along with moderate gain make the proposed antenna suitable for above mentioned applications. Details of the antenna design and simulated results Return loss, Input impedance, Radiation Patterns, E-Field, H-Field and Current Distributions, VSWR are presented and discussed. The proposed antenna is simulated at 2.4 GHz using Ansoft HFSS-11.

  12. Liquid Crystal Bow-Tie Microstrip antenna for Wireless Communication Applications

    OpenAIRE

    B.T.P.Madhav; VGKM Pisipati; Habibulla Khan; V.G.N.S Prasad; K. Praveen Kumar; KVL Bhavani; M. Ravi Kumar

    2014-01-01

    In this paper we presented the design and analysis of Bow-Tie antenna on liquid crystal substrate, which is suitable for the Bluetooth/WLAN-2.4/WiBree/ZigBee applications. The Omni-directional radiation patterns along with moderate gain make the proposed antenna suitable for above mentioned applications. Details of the antenna design and simulated results Return loss, Input impedance, Radiation Patterns, E-Field, H-Field and Current Distributions, VSWR are presented and discussed. The propose...

  13. Bow-tie optical antenna probes for single-emitter scanning near-field optical microscopy

    OpenAIRE

    Farahani, Javad N.; Eisler, Hans-Jürgen; Pohl, Dieter W; Pavius, Michaël; Flückiger, Philippe; Gasser, Philippe; Hecht, Bert

    2007-01-01

    A method for the fabrication of bow-tie optical antennas at the apex of pyramidal Si3N4 atomic force microscopy tips is described. We demonstrate that these novel optical probes are capable of sub-wavelength imaging of single quantum dots at room temperature. The enhanced and confined optical near-field at the antenna feed gap leads to locally enhanced photoluminescence (PL) of single quantum dots. Photoluminescence quenching due to the proximity of metal is found to be insignificant. The met...

  14. Millimeter-wave near-field imaging with bow-tie antennas.

    Science.gov (United States)

    Omarouayache, Rachid; Payet, Pierre; Raoult, Jérémy; Chusseau, Laurent

    2015-05-01

    A near-field reflectometry experiment operating at 60 GHz is built in view of material and circuit inspection. Experiments are always obtained in constant height mode of operation. The bow-tie near-field probe acts mostly as a linearly-polarized electric dipole and allows strongly subwavelength resolution of ≈ λ/130. Its interaction with sample is shown polarization dependent and sensitive to both the local topography and the local dielectric constant or metal conductivity. Resonant and non-resonant probes are both evaluated. PMID:25969302

  15. Printed Modified Bow-Tie Dipole Antenna for DVB/WLAN Applications

    Directory of Open Access Journals (Sweden)

    Ching-Chih Hung

    2013-01-01

    Full Text Available A printed modified bow-tie dipole antenna which consists of asymmetric-feed and inserted slots is presented to apply to the DVB and WLAN systems. This antenna combines omnidirectional radiation pattern, broad bandwidth, and band rejection in an easy way to fabricate. Experimental results of the constructed prototype indicate that the VSWR 2.5 : 1 bandwidths achieve 166.7%, 28.57%, and 23.63% at 660 MHz, 2450 MHz, and 5500 MHz, respectively.

  16. Printed Modified Bow-Tie Dipole Antenna for DVB/WLAN Applications

    OpenAIRE

    Ching-Chih Hung; Chia-Mei Peng; I-Fong Chen

    2013-01-01

    A printed modified bow-tie dipole antenna which consists of asymmetric-feed and inserted slots is presented to apply to the DVB and WLAN systems. This antenna combines omnidirectional radiation pattern, broad bandwidth, and band rejection in an easy way to fabricate. Experimental results of the constructed prototype indicate that the VSWR 2.5 : 1 bandwidths achieve 166.7%, 28.57%, and 23.63% at 660 MHz, 2450 MHz, and 5500 MHz, respectively.

  17. Beam-Steerable Microstrip-Fed Bow-Tie Antenna Array for Fifth Generation Cellular Communications

    OpenAIRE

    Ojaroudiparchin, Naser; Shen, Ming; Gert F. Pedersen

    2016-01-01

    The design and performance of mm-wave phased array antenna for 5G mobile broadband communication systems has been provided in this manuscript. The antenna is designed on a N9000 PTFE substrate with 0.787 mm thickness and 2.2 dielectric constant and 65×130 mm2 overall dimension. Eight elements of bow-tie antennas have been used at the top-edge region of mobile phone PCB. The antenna elements fed by microstrip lines are designed to operate at 17 GHz. The simulated results give good performances...

  18. Analytic MHD Theory for Earth's Bow Shock at Low Mach Numbers

    Science.gov (United States)

    Grabbe, Crockett L.; Cairns, Iver H.

    1995-01-01

    A previous MHD theory for the density jump at the Earth's bow shock, which assumed the Alfven M(A) and sonic M(s) Mach numbers are both much greater than 1, is reanalyzed and generalized. It is shown that the MHD jump equation can be analytically solved much more directly using perturbation theory, with the ordering determined by M(A) and M(s), and that the first-order perturbation solution is identical to the solution found in the earlier theory. The second-order perturbation solution is calculated, whereas the earlier approach cannot be used to obtain it. The second-order terms generally are important over most of the range of M(A) and M(s) in the solar wind when the angle theta between the normal to the bow shock and magnetic field is not close to 0 deg or 180 deg (the solutions are symmetric about 90 deg). This new perturbation solution is generally accurate under most solar wind conditions at 1 AU, with the exception of low Mach numbers when theta is close to 90 deg. In this exceptional case the new solution does not improve on the first-order solutions obtained earlier, and the predicted density ratio can vary by 10-20% from the exact numerical MHD solutions. For theta approx. = 90 deg another perturbation solution is derived that predicts the density ratio much more accurately. This second solution is typically accurate for quasi-perpendicular conditions. Taken together, these two analytical solutions are generally accurate for the Earth's bow shock, except in the rare circumstance that M(A) is less than or = 2. MHD and gasdynamic simulations have produced empirical models in which the shock's standoff distance a(s) is linearly related to the density jump ratio X at the subsolar point. Using an empirical relationship between a(s) and X obtained from MHD simulations, a(s) values predicted using the MHD solutions for X are compared with the predictions of phenomenological models commonly used for modeling observational data, and with the predictions of a

  19. A benchmark study of procedures for analysis of axial crushing of bulbous bows

    OpenAIRE

    Yamada, Yasuhira; Pedersen, Preben Terndrup

    2008-01-01

    Simplified methods to estimate mean axial crushing forces of plated structures are reviewed and applied to a series of experimental results for axial crushing of large-scale bulbous bow models. Methods based on intersection unit elements such as L-, T- and X-type elements as well as methods based on plate unit elements are employed in the analyses. The crushing forces and the total absorbed energy obtained by the simplified analyses are compared with those obtained from large-scale bulbous bo...

  20. Bowing effect in elastic constants of dilute Ga(As,N) alloys

    Science.gov (United States)

    Berggren, Jonas; Hanke, Michael; Trampert, Achim

    2016-05-01

    We study the elastic properties of dilute Ga(As,N) thin films grown on GaAs(001) by means of nano-indentation and complementary dynamic finite element calculations. The experimental results of indentation modulus are compared with simulations in order to extract the cubic elastic constants cij as a function of nitrogen content of the Ga(As,N) alloys. Both, indentation modulus and elastic constants decrease with increasing nitrogen content, which proves a strong negative bowing effect in this system in contrast to Vegard's law.

  1. Free-hanging bow measurements of LWBR fuel rods (LWBR Development Program)

    International Nuclear Information System (INIS)

    Special inspection equipment was developed to ensure that the fuel rods for the Light Water Breeder Reactor met the required straightness criteria. The fuel rods were hung in a vertical position and the free-hanging shape was measured. These data were then used analytically to predict both the forces required to constrain the rods in a grid array and the resultant restrained shape. The development of a computerized system which was used for measuring the free-hanging bow of fuel rods used in the LWBR core is described in this paper

  2. Asymptotic Steady State Solution to a Bow Shock with an Infinite Mach Number

    CERN Document Server

    Yalinewich, Almog

    2015-01-01

    The problem of a cold gas flowing past a stationary object is considered. It is shown that at large distances from the obstacle the shock front forms a parabolic solid of revolution. The interior of the shock front is obtained by solution of the hydrodynamic equations in parabolic coordinates. The results are verified with a hydrodynamic simulation. The drag force and expected spectra are calculated for such shock, both in case of an optically thin and thick media. Finally, relations to astrophysical bow shocks and other analytic works on oblique shocks are discussed.

  3. Broadband millimeter-wave GaAs transmitters and receivers using planar bow-tie antennas

    Science.gov (United States)

    Konishi, Y.; Kamegawa, M.; Case, M.; Yu, R.; Rodwell, M. J. W.; York, R. A.; Rutledge, D. B.

    1992-01-01

    We report broadband monolithic transmitters and receivers IC's for mm-wave electromagnetic measurements. The IC's use nonlinear transmission lines (NLTL) and sampling circuits as picosecond pulse generators and detectors. The pulses are radiated and received by planar monolithic bow-tie antennas, collimated with silicon substrate lenses and off-axis parabolic reflectors. Through Fourier transformation of the received pulse, 30-250 GHz free space gain-frequency measurements are demonstrated with an accuracy approximately = 0.17 dB, RMS.

  4. Mapping the Structure of Directed Networks: Beyond the "Bow-tie" Diagram

    CERN Document Server

    Timár, G; Dorogovtsev, S N; Mendes, J F F

    2016-01-01

    We reveal a hierarchical organization of finite directed components---tendrils---around the giant components represented by the celebrated "bow-tie" diagram for directed networks. We develop an efficient algorithm to find tendril layers. It is used together with the message passing technique, generalized to directed graphs, to find the structure and attack tolerance of complex networks, such as the World Wide Web, the neural network of Caenorhabditis elegans, and others. We introduce a generalized susceptibility characterizing the response of directed networks to damage.

  5. Southeastern Power Administration 2007 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2007-12-28

    Dear Secretary Chu: I am proud to submit Southeastern Power Administration’s (Southeastern’s) fiscal year (FY) 2007 Annual Report for your review. The information included in this report reflects Southeastern’s programs, accomplishments, and financial activities for the 12-month period beginning October 1, 2006 and ending September 30, 2007. Southeastern marketed more than 5 billion kilowatt-hours of energy to 492 wholesale Federal power customers in an 11-state marketing area in FY 2007. Revenues from the sale of this power totaled approximately $219 million. Drought conditions continued to plague the southeast region of the United States during 2007 placing strains on our natural and financial resources. Southeastern purchased more than $40 million in replacement power to meet customer contract requirements to ensure the continued reliability of our nation’s power grid. With the financial assistance and support of our Federal power customers, continued funding for capitalized equipment replacements at various Corps of Engineers’ (Corps) hydroelectric projects provided much needed repairs and maintenance for aging facilities. Southeastern’s cyber and physical security program continued to be reviewed and updated to meet Department of Energy (DOE), Homeland Security, and North American Electric Reliability Corporation standards and requirements. Plans for the upcoming year include communication and cooperation with DOE, Federal power customers, and the Corps to maximize the benefits of our nation’s water resources. Competition for the use of water and the prolonged drought conditions will present another challenging year for our agency. The employees at Southeastern will be proactive in meeting these challenges and providing reliable hydroelectric power to the people in the southeast. Sincerely, Kenneth E. Legg Administrator

  6. Fire ecology in the southeastern United States

    Science.gov (United States)

    ,

    2000-01-01

    Fire has played an important role in the structure of natural ecosystems throughout North America. As a natural process, fire helps clear away dead and dying plant matter and increases the production of native species that occur in fire prone habitats. It also reduces the invasion of exotic species and the succession to woody species in pitcher plant bogs, pine savannas, coastal prairies, marshes, and other natural plant communities of the southeastern United States.

  7. Assessment of Genitourinary Trauma in Southeastern Iran

    OpenAIRE

    Sabzi Sarvestani, Amene; Zamiri, Mehdi

    2013-01-01

    Background To survey genitourinary (GU) organ injury following general trauma, we performed an epidemiologic study of urogenital injuries in trauma patients referred to our hospital (a teaching hospital affiliated with the Zahedan University of Medical Sciences). Objectives We aimed to assess the epidemiology of urogenital system injuries in southeastern Iran. Patients and Methods From April 2009 to November 2011, all patients with GU injuries referred to our hospital were studied. The data i...

  8. Finite-element procedure for calculating the three-dimensional inelastic bowing of fuel rods (AWBA development program)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, S E

    1982-05-01

    An incremental finite element procedure is developed for calculating the in-pile lateral bowing of nuclear fuel rods. The fuel rod is modeled as a viscoelastic beam whose material properties are derived as perturbations of the results of an axisymmetric stress analysis of the fuel rod. The effects which are taken into account in calculating the rod's lateral bowing include: (a) lateral, axial, and rotational motions and forces at the rod supports, (b) transverse gradients of temperature, fast-neutron flux, and fissioning rate, and (c) cladding circumferential wall thickness variation. The procedure developed in this report could be used to form the basis for a computer program to calculate the time-dependent bowing as a function of the fuel rod's operational and environmental history.

  9. High-Temperature Processing of Solids Through Solar Nebular Bow Shocks: 3D Radiation Hydrodynamics Simulations with Particles

    CERN Document Server

    Boley, A C; Desch, S J

    2013-01-01

    A fundamental, unsolved problem in Solar System formation is explaining the melting and crystallization of chondrules found in chondritic meteorites. Theoretical models of chondrule melting in nebular shocks has been shown to be consistent with many aspects of thermal histories inferred for chondrules from laboratory experiments; but, the mechanism driving these shocks is unknown. Planetesimals and planetary embryos on eccentric orbits can produce bow shocks as they move supersonically through the disk gas, and are one possible source of chondrule-melting shocks. We investigate chondrule formation in bow shocks around planetoids through 3D radiation hydrodynamics simulations. A new radiation transport algorithm that combines elements of flux-limited diffusion and Monte Carlo methods is used to capture the complexity of radiative transport around bow shocks. An equation of state that includes the rotational, vibrational, and dissociation modes of H$_2$ is also used. Solids are followed directly in the simulati...

  10. A new technique to characterize CT scanner bow-tie filter attenuation and applications in human cadaver dosimetry simulations

    International Nuclear Information System (INIS)

    Purpose: To present a noninvasive technique for directly measuring the CT bow-tie filter attenuation with a linear array x-ray detector. Methods: A scintillator based x-ray detector of 384 pixels, 307 mm active length, and fast data acquisition (model X-Scan 0.8c4-307, Detection Technology, FI-91100 Ii, Finland) was used to simultaneously detect radiation levels across a scan field-of-view. The sampling time was as short as 0.24 ms. To measure the body bow-tie attenuation on a GE Lightspeed Pro 16 CT scanner, the x-ray tube was parked at the 12 o’clock position, and the detector was centered in the scan field at the isocenter height. Two radiation exposures were made with and without the bow-tie in the beam path. Each readout signal was corrected for the detector background offset and signal-level related nonlinear gain, and the ratio of the two exposures gave the bow-tie attenuation. The results were used in the GEANT4 based simulations of the point doses measured using six thimble chambers placed in a human cadaver with abdomen/pelvis CT scans at 100 or 120 kV, helical pitch at 1.375, constant or variable tube current, and distinct x-ray tube starting angles. Results: Absolute attenuation was measured with the body bow-tie scanned at 80–140 kV. For 24 doses measured in six organs of the cadaver, the median or maximum difference between the simulation results and the measurements on the CT scanner was 8.9% or 25.9%, respectively. Conclusions: The described method allows fast and accurate bow-tie filter characterization

  11. A new technique to characterize CT scanner bow-tie filter attenuation and applications in human cadaver dosimetry simulations

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xinhua; Shi, Jim Q.; Zhang, Da; Singh, Sarabjeet; Padole, Atul; Otrakji, Alexi; Kalra, Mannudeep K.; Liu, Bob, E-mail: bliu7@mgh.harvard.edu [Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Xu, X. George [Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-11-15

    Purpose: To present a noninvasive technique for directly measuring the CT bow-tie filter attenuation with a linear array x-ray detector. Methods: A scintillator based x-ray detector of 384 pixels, 307 mm active length, and fast data acquisition (model X-Scan 0.8c4-307, Detection Technology, FI-91100 Ii, Finland) was used to simultaneously detect radiation levels across a scan field-of-view. The sampling time was as short as 0.24 ms. To measure the body bow-tie attenuation on a GE Lightspeed Pro 16 CT scanner, the x-ray tube was parked at the 12 o’clock position, and the detector was centered in the scan field at the isocenter height. Two radiation exposures were made with and without the bow-tie in the beam path. Each readout signal was corrected for the detector background offset and signal-level related nonlinear gain, and the ratio of the two exposures gave the bow-tie attenuation. The results were used in the GEANT4 based simulations of the point doses measured using six thimble chambers placed in a human cadaver with abdomen/pelvis CT scans at 100 or 120 kV, helical pitch at 1.375, constant or variable tube current, and distinct x-ray tube starting angles. Results: Absolute attenuation was measured with the body bow-tie scanned at 80–140 kV. For 24 doses measured in six organs of the cadaver, the median or maximum difference between the simulation results and the measurements on the CT scanner was 8.9% or 25.9%, respectively. Conclusions: The described method allows fast and accurate bow-tie filter characterization.

  12. STRAWBERRY MOUNTAIN WILDERNESS, OREGON.

    Science.gov (United States)

    Thayer, T.P.; Stotelmeyer, Ronald B.

    1984-01-01

    The Strawberry Mountain Wilderness extends 18 mi along the crest of the Strawberry Range and comprises about 53 sq mi in the Malheur National Forest, Grant County, Oregon. Systematic geologic mapping, geochemical sampling and detailed sampling of prospect workings was done. A demonstrated copper resource in small quartz veins averaging at most 0. 33 percent copper with traces of silver occurs in shear zones in gabbro. Two small areas with substantiated potential for chrome occur near the northern edge of the wilderness. There is little promise for the occurrence of additional mineral or energy resources in the Strawberry Mountain Wilderness.

  13. The spin-1/2 Ising model on the bow-tie lattice as an exactly soluble free-fermion model

    OpenAIRE

    Strecka, Jozef; Canova, Lucia

    2007-01-01

    The spin-1/2 Ising model on the bow-tie lattice is exactly solved by establishing a precise mapping relationship with its corresponding free-fermion eight-vertex model. Ground-state and finite-temperature phase diagrams are obtained for the anisotropic bow-tie lattice with three different exchange interactions along three different spatial directions.

  14. Elastic analysis of thermal gradient bowing in rod-type fuel elements subjected to axial thrust (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Newman, J.B.

    1968-01-01

    Thermal radient bowing of rod type fuel elements can be analyzed in terms of the deflections of a precurved beam. The fundamental aspects of an analysis of axially compressed multispan beams are given. Elasticity of supports in both axial and transverse directions is considered; the technique is applicable to problems in which the axial thrust depends on the transverse deflection as well as problems with prescribed axial thrust. The formulas presented constitute the theory for a computer program of broad applicability, not only in the analysis of fuel rod bowing, but also to almost any multispan beam, particularly when the effects of axial loads cannot be neglected. 17 references. (NSA 22: 22866)

  15. Recent H-alpha Results on Pulsar B2224+65's Bow-Shock Nebula, the "Guitar"

    Science.gov (United States)

    Dolch, Timothy; Chatterjee, Shami; Clemens, Dan P.; Cordes, James M.; Cashmen, Lauren R.; Taylor, Brian W.

    2016-09-01

    We used the 4 m Discovery Channel Telescope (DCT) at Lowell observatory in 2014 to observe the Guitar Nebula, an Hα bow-shock nebula around the high-velocity radio pulsar B2224+65. Since the nebula's discovery in 1992, the structure of the bow-shock has undergone significant dynamical changes. We have observed the limb structure, targeting the “body” and “neck” of the guitar. Comparing the DCT observations to 1995 observations with the Palomar 200-inch Hale telescope, we found changes in both spatial structure and surface brightness in the tip, head, and body of the nebula.

  16. Offset semi-parabolic nanoantenna made of a photonic crystal parabolic mirror and a plasmonic bow-tie antenna.

    Science.gov (United States)

    Hattori, Haroldo T

    2014-10-10

    In a parabolic mirror, light coming parallel to the antenna passes through its focal point. In this work, a waveguide feeds a semi-parabolic photonic crystal mirror and the emerging beam feeds a bow-tie antenna placed at the mirror's focal point-it is shown that the antenna system can not only feed a bow-tie antenna (producing a localized moderately high electric field) but also produces a directional radiation beam. The semi-parabolic mirror is also modified to reduce reflection back to the feeding waveguide. PMID:25322381

  17. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    OpenAIRE

    Seung-Hyun Eom; Yunsik Seo; Sungjoon Lim

    2015-01-01

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antenn...

  18. Experimental validation of a method characterizing bow tie filters in CT scanners using a real-time dose probe

    OpenAIRE

    McKenney, Sarah E.; Nosratieh, Anita; Gelskey, Dale; Yang, Kai; Huang, Shin-ying; Chen, Lin; Boone, John M.

    2011-01-01

    Purpose: Beam-shaping or “bow tie” (BT) filters are used to spatially modulate the x-ray beam in a CT scanner, but the conventional method of step-and-shoot measurement to characterize a beam’s profile is tedious and time-consuming. The theory for characterization of bow tie relative attenuation (COBRA) method, which relies on a real-time dosimeter to address the issues of conventional measurement techniques, was previously demonstrated using computer simulations. In this study, the feasibili...

  19. Offset semi-parabolic nanoantenna made of a photonic crystal parabolic mirror and a plasmonic bow-tie antenna.

    Science.gov (United States)

    Hattori, Haroldo T

    2014-10-10

    In a parabolic mirror, light coming parallel to the antenna passes through its focal point. In this work, a waveguide feeds a semi-parabolic photonic crystal mirror and the emerging beam feeds a bow-tie antenna placed at the mirror's focal point-it is shown that the antenna system can not only feed a bow-tie antenna (producing a localized moderately high electric field) but also produces a directional radiation beam. The semi-parabolic mirror is also modified to reduce reflection back to the feeding waveguide.

  20. Absence of the bowing character in the common-anion II-VI ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tit, Nacir [Department of Physics, UAE University, P.O. Box 17551, Al-Ain (United Arab Emirates)], E-mail: ntit@uaeu.ac.ae; Obaidat, Ihab M. [Department of Physics, UAE University, P.O. Box 17551, Al-Ain (United Arab Emirates); Alawadhi, Hussain [Department of Applied Physics, University of Sharjah, P.O. Box 27272, Sharjah (United Arab Emirates)

    2009-07-29

    The absence of bandgap bowing in the common-anion II-VI semiconductor ternary alloys is investigated. As examples, we consider the Cd{sub 1-x}Zn{sub x}Te and Cd{sub 1-x}Zn{sub x}Se alloys. The sp{sup 3}s* tight-binding method with the inclusion of spin-orbit interactions is employed to calculate the alloy's band structure and its corresponding constituents' charge states (ionicities) as a function of composition. The variation is found to be nearly linear. The vanishingly small valence-band offset (VBO{approx_equal}0) in common-anion compounds would yield a linear scaling of bandgap energy with composition, especially as the conduction-band edge state being a singlet state with spherical symmetry. Furthermore, the two cation atoms (Cd and Zn) are found not to compete in changing their charge states as the composition is varied. The absence of such competition is believed to be the main reason for the absence of bowing. The theoretical results are compared to the available experimental data and found to be in good agreement.

  1. Ground-state magnetic phase diagram of bow-tie graphene nanoflakes in external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Szałowski, Karol, E-mail: kszalowski@uni.lodz.pl, E-mail: kszalowski@wp.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, ul. Pomorska 149/153, 90-236 Łódź (Poland)

    2013-12-28

    The magnetic phase diagram of a ground state is studied theoretically for graphene nanoflakes of bow-tie shape and various sizes in external in-plane magnetic field. The tight-binding Hamiltonian supplemented with Hubbard term is used to model the electronic structure of the systems in question. The existence of the antiferromagnetic phase with magnetic moments localized at the sides of the bow-tie is found for low field and a field-induced spin-flip transition to ferromagnetic state is predicted to occur in charge-undoped structures. For small nanoflake doped with a single charge carrier, the low-field phase is ferrimagnetic and a metamagnetic transition to ferromagnetic ordering can be forced by the field. The critical field is found to decrease with increasing size of the nanoflake. The influence of diagonal and off-diagonal disorder on the mentioned magnetic properties is studied. The effect of off-diagonal disorder is found to be more important than that of diagonal disorder, leading to significantly widened distribution of critical fields for disordered population of nanoflakes.

  2. The excitation conditions of magnetospheric convection by the electric current generated in the bow shock

    Science.gov (United States)

    Sedykh, P. A.; Ponomarev, E. A.

    The solar wind undergoes the greatest change of its parameters during the passage through the bow shock front Its density in this case increases by the factor of four and gas and magnetic pressure increase more than by an order of magnitude In this paper we re-examine the consequences of the fact of electric current generation at the bow shock front that we considered at an earlier date and the dependence of the direction of this current on the sign of IMF Bz-component The first consequence is the closure of the aforementioned current through the magnetosphere It was found that this process is a two-stage one Initially the electric field penetrates and establishes in the medium a new convective regime After that depending on the degree of flow inhomogeneity a plasma density distribution can be established which corresponds to the electric current equal to the external current The new steady state to which the new convection velocity field and the new plasma pressure field correspond is established within the time of the order of the transit time taken by the magnetosonic wave to propagate through the entire system Also a linkage between the power dissipated inside the magnetosphere and the parameters of plasma convection existing therein is shown

  3. Accelerated cometary ions observed downstream of the Comet Halley bow shock

    Science.gov (United States)

    Kecskemety, K.; Cravens, T. E.

    1992-01-01

    Results are presented of fluxes of energetic ions with energies exceeding 100 keV that were detected upstream of the bow shock of Comet Halley by the Tuende instrument on board the VEGA 1 spacecraft. Downstream of the shock, ion fluxes in the energy range 100 to 180 keV were observed. The measured ion fluxes were transformed into distribution functions in the solar wind frame using a variety of assumptions concerning the energy dependence of the distribution function and the identity of the ion species. The derived distribution function upstream of the shock falls off steeply with energy between 100 and 150 keV, with an effective temperature of about 7 keV or spectral index of about -15. The distribution function increases with decreasing cometocentric distance, on average, reaching a maximum at the bow shock. The measured distribution functions are compared with those obtained by similar instruments on Giotto and ICE as well as with the predictions of several theoretical models that employ different acceleration mechanisms.

  4. The properties of bow-shock sources at the Galactic Center

    CERN Document Server

    Sanchez-Bermudez, J; Alberdi, A; Muzic, K; Hummel, C A; Pott, J -U

    2014-01-01

    There are an enigmatic population of massive stars around the Galactic Center (GC) that were formed some Ma ago. A fraction of these stars has been found to orbit the supermassive black hole, SgrA*, in a projected clockwise disk, which suggests that they were formed in a formerly existing dense disk around SgrA*. We focus on the extended, near-infrared (NIR) sources IRS1W, IRS5, IRS10W, and IRS21 that have been suggested to be young, massive stars that form bow-shocks through their interaction with the ISM. Their nature has impeded accurate determination of their orbital parameters. We aim at establishing their nature and kinematics to test whether they form part of the clockwise disk. We performed NIR multi-wavelength imaging using adaptive optics (AO) and sparse aperture masking (SAM). We introduce a new method for self-calibration of the SAM PSF in dense stellar fields. The emission mechanism, morphology and kinematics of the targets were examined via 3D bow-shock models. We confirm previous findings that ...

  5. O+ ion beams reflected below the Martian bow shock: MAVEN observations

    Science.gov (United States)

    Masunaga, K.; Seki, K.; Brain, D. A.; Fang, X.; Dong, Y.; Jakosky, B. M.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.

    2016-04-01

    We investigate a generation mechanism of O+ ion beams observed above the Martian bow shock by analyzing ion velocity distribution functions (VDFs) measured by the Suprathermal and Thermal Ion Composition instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. In the solar wind near Mars, MAVEN often observes energetic O+ ion beams (~10 keV or higher). Accompanied with the O+ ion beam events, we sometimes observe characteristic ion VDFs in the magnetosheath: a partial ring distribution. The partial ring distribution corresponds to pickup ions with a finite initial velocity (i.e., not newborn pickup ions), and its phase space density is much smaller than that of local pickup O+ ions of the magnetosheath. Thus, the partial ring distribution is most likely produced by the reflection of pickup O+ ions precipitating from the upstream solar wind below the bow shock. After being injected into the magnetosheath from the solar wind, the precipitating O+ ions are subject to the significantly enhanced magnetic field in this region and start to gyrate around the guiding center of the plasma frame in the magnetosheath. Consequently, a part of precipitating O+ ions are reflected back to the solar wind, generating O+ beams in the solar wind. The beams direct quasi-sunward near the subsolar region but have large angle with respect to the sunward direction at high solar zenith angles (>50°). The reflected O+ beams are accelerated by the convection electric field of the solar wind and may escape Mars.

  6. Optical hydrogen absorption consistent with a thin bow shock leading the hot Jupiter HD 189733b

    CERN Document Server

    Cauley, P Wilson; Jensen, Adam G; Barman, Travis; Endl, Michael; Cochran, William D

    2015-01-01

    Bow shocks are ubiquitous astrophysical phenomena resulting from the supersonic passage of an object through a gas. Recently, pre-transit absorption in UV metal transitions of the hot Jupiter exoplanets HD 189733b and WASP12-b have been interpreted as being caused by material compressed in a planetary bow shock. Here we present a robust detection of a time-resolved pre-transit, as well as in-transit, absorption signature around the hot Jupiter exoplanet HD 189733b using high spectral resolution observations of several hydrogen Balmer lines. The line shape of the pre-transit feature and the shape of the time series absorption provide the strongest constraints on the morphology and physical characteristics of extended structures around an exoplanet. The in-transit measurements confirm the previous exospheric H-alpha detection although the absorption depth measured here is ~50% lower. The pre-transit absorption feature occurs 125 minutes before the predicted optical transit, a projected linear distance from the ...

  7. Reconstructing the Guitar: Blowing Bubbles with a Pulsar Bow Shock Back Flow

    CERN Document Server

    van Kerkwijk, Marten H

    2008-01-01

    The Guitar Nebula is an H-alpha nebula produced by the interaction of the relativistic wind of a very fast pulsar, PSR B2224+65, with the interstellar medium. It consists of a ram-pressure confined bow shock near its head and a series of semi-circular bubbles further behind, the two largest of which form the body of the Guitar. We present a scenario in which this peculiar morphology is due to instabilities in the back flow from the pulsar bow shock. From simulations, these back flows appear similar to jets and their kinetic energy is a large fraction of the total energy in the pulsar's relativistic wind. We suggest that, like jets, these flows become unstable some distance down-stream, leading to rapid dissipation of the kinetic energy into heat, and the formation of an expanding bubble. We show that in this scenario the sizes, velocities, and surface brightnesses of the bubbles depend mostly on observables, and that they match roughly what is seen for the Guitar. Similar instabilities may account for feature...

  8. PKS B1545-321: Bow shocks of a relativistic jet?

    CERN Document Server

    Safouris, V; Bicknell, G; Saripalli, L

    2008-01-01

    Sensitive, high resolution images of the double-double radio galaxy PKS B1545-321 reveal detailed structure, which we interpret in the light of previous work on the interaction of restarted jets with pre-existing relict cocoons. We have also examined the spectral and polarization properties of the source, the color distribution in the optical host and the environment of this galaxy in order to understand its physical evolution. We propose that the restarted jets generate narrow bow shocks and that the inner lobes are a mixture of cocoon plasma reaccelerated at the bow shock and new jet material reaccelerated at the termination shock. The dynamics of the restarted jets implies that their hot spots advance at mildly relativistic speeds with external Mach numbers of at least 5. The existence of supersonic hot spot Mach numbers and bright inner lobes is the result of entrainment causing a reduction in the sound speed of the pre-existing cocoon. The interruption to jet activity in PKS B1545-321 has been brief - la...

  9. Technical Note: Measurement of bow tie profiles in CT scanners using radiochromic film

    Energy Technology Data Exchange (ETDEWEB)

    Whiting, Bruce R., E-mail: whitingbrucer@gmail.com [Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 (United States); Dohatcu, Andreea C. [University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213 (United States); Evans, Joshua D.; Williamson, Jeffrey F. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Politte, David G. [Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63110 (United States)

    2015-06-15

    Purpose: To provide a noninvasive technique to measure the intensity profile of the fan beam in a computed tomography (CT) scanner that is cost effective and easily implemented without the need to access proprietary scanner information or service modes. Methods: The fabrication of an inexpensive aperture is described, which is used to expose radiochromic film in a rotating CT gantry. A series of exposures is made, each of which is digitized on a personal computer document scanner, and the resulting data set is analyzed to produce a self-consistent calibration of relative radiation exposure. The bow tie profiles were analyzed to determine the precision of the process and were compared to two other measurement techniques, direct measurements from CT gantry detectors and a dynamic dosimeter. Results: The radiochromic film method presented here can measure radiation exposures with a precision of ∼6% root-mean-square relative error. The intensity profiles have a maximum 25% root-mean-square relative error compared with existing techniques. Conclusions: The proposed radiochromic film method for measuring bow tie profiles is an inexpensive (∼$100 USD + film costs), noninvasive method to measure the fan beam intensity profile in CT scanners.

  10. Investigation of radiative bow-shocks in magnetically accelerated plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Bott-Suzuki, S. C., E-mail: sbottsuzuki@ucsd.edu; Caballero Bendixsen, L. S.; Cordaro, S. W. [University of California San Diego, La Jolla, California 92093 (United States); Blesener, I. C.; Hoyt, C. L.; Cahill, A. D.; Kusse, B. R.; Hammer, D. A.; Gourdain, P. A.; Seyler, C. E.; Greenly, J. B. [Cornell University, Ithaca, New York 14850 (United States); Chittenden, J. P.; Niasse, N.; Lebedev, S. V. [Imperial College London, South Kensington, London SW7 2BW (United Kingdom); Ampleford, D. J. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    2015-05-15

    We present a study of the formation of bow shocks in radiatively cooled plasma flows. This work uses an inverse wire array to provide a quasi-uniform, large scale hydrodynamic flow accelerated by Lorentz forces to supersonic velocities. This flow impacts a stationary object placed in its path, forming a well-defined Mach cone. Interferogram data are used to determine a Mach number of ∼6, which may increase with radial position suggesting a strongly cooling flow. Self-emission imaging shows the formation of a thin (<60 μm) strongly emitting shock region, where T{sub e} ∼ 40–50 eV, and rapid cooling behind the shock. Emission is observed upstream of the shock position which appears consistent with a radiation driven phenomenon. Data are compared to 2-dimensional simulations using the Gorgon MHD code, which show good agreement with the experiments. The simulations are also used to investigate the effect of magnetic field in the target, demonstrating that the bow-shocks have a high plasma β, and the influence of B-field at the shock is small. This consistent with experimental measurement with micro bdot probes.

  11. Compound semiconductor alloys: From atomic-scale structure to bandgap bowing

    Energy Technology Data Exchange (ETDEWEB)

    Schnohr, C. S., E-mail: c.schnohr@uni-jena.de [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany)

    2015-09-15

    Compound semiconductor alloys such as In{sub x}Ga{sub 1−x}As, GaAs{sub x}P{sub 1−x}, or CuIn{sub x}Ga{sub 1−x}Se{sub 2} are increasingly employed in numerous electronic, optoelectronic, and photonic devices due to the possibility of tuning their properties over a wide parameter range simply by adjusting the alloy composition. Interestingly, the material properties are also determined by the atomic-scale structure of the alloys on the subnanometer scale. These local atomic arrangements exhibit a striking deviation from the average crystallographic structure featuring different element-specific bond lengths, pronounced bond angle relaxation and severe atomic displacements. The latter, in particular, have a strong influence on the bandgap energy and give rise to a significant contribution to the experimentally observed bandgap bowing. This article therefore reviews experimental and theoretical studies of the atomic-scale structure of III-V and II-VI zincblende alloys and I-III-VI{sub 2} chalcopyrite alloys and explains the characteristic findings in terms of bond length and bond angle relaxation. Different approaches to describe and predict the bandgap bowing are presented and the correlation with local structural parameters is discussed in detail. The article further highlights both similarities and differences between the cubic zincblende alloys and the more complex chalcopyrite alloys and demonstrates that similar effects can also be expected for other tetrahedrally coordinated semiconductors of the adamantine structural family.

  12. Woods with physical, mechanical and acoustic properties similar to those of Caesalpinia echinata have high potential as alternative woods for bow makers

    Directory of Open Access Journals (Sweden)

    Eduardo Luiz Longui

    2014-09-01

    Full Text Available For nearly two hundred years, Caesalpinia echinata wood has been the standard for modern bows. However, the threat of extinction and the enforcement of trade bans have required bow makers to seek alternative woods. The hypothesis tested was that woods with physical, mechanical and acoustic properties similar to those of C. echinata would have high potential as alternative woods for bows. Accordingly, were investigated Handroanthus spp., Mezilaurus itauba, Hymenaea spp., Dipteryx spp., Diplotropis spp. and Astronium lecointei. Handroanthus and Diplotropis have the greatest number of similarities with C. echinata, but only Handroanthus spp. showed significant results in actual bow manufacture, suggesting the importance of such key properties as specific gravity, speed of sound propagation and modulus of elasticity. In practice, Handroanthus and Dipteryx produced bows of quality similar to that of C. echinata.

  13. Source rock geochemistry and liquid and solid petroleum occurrences of the Ouachita Mountains, Oklahoma

    Science.gov (United States)

    Curiale, J. A.

    Crude oils, solid bitumens and potential oil source rocks of the frontal and central Ouachita Mountains of southeastern Oklahoma are examined. The organic matter in each of these materials is characterized, and oils are correlated to potential source rocks in the Ouachita Mountains. Four Ouachita Mountain oils and seven solid bitumens (grahamite and impsonite) are analyzed. The oils are paraffinic and range from 31.8 to 43.1 API gravity. The oils are thermally mature and generally unaltered. All four oils are commonly sourced, by n-alkane, sterane and hopane distributions, stable isotope ratios, infrared spectra and vanadium/nickel ratios. A common source for the solid bitumens is also suggested by isotope ratios and pyrolyzate characteristics. An origin due to crude oil biodegradation is suggested for these solids, based on carbon isotope ratios, elemental analyses, and sterane distributions of the solid bitumen pyrolyzates.

  14. Rocky Mountain Perspectives.

    Science.gov (United States)

    Dutkiewicz, Jody Steiner, Ed.

    This publication features articles detailing the state of educational programs in the Rocky Mountain area. The articles address: 1) the impact of physical geography on culture, education, and lifestyle; 2) the education of migrant and/or agricultural workers and their children; 3) educational needs of children in rural areas; 4) outdoor education;…

  15. Xiuhua Mountain Museum

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    XIUHUA Mountain Museum,a building nestled amongthe hills,is the first private museum of the Tujiaethnicity.Its name is an amalgamation of the names ofthe couple who run it,Gong Daoxiu and her husband ChenChuhua.According to Chen,the reason that he put his wife’s

  16. [Mountaineering and altitude sickness].

    Science.gov (United States)

    Maggiorini, M

    2001-06-01

    Almost every second trekker or climber develops two to three symptoms of the high altitude illness after a rapid ascent (> 300 m/day) to an altitude above 4000 m. We distinguish two forms of high altitude illness, a cerebral form called acute mountain sickness and a pulmonary form called high altitude pulmonary edema. Essentially, acute mountain sickness is self-limiting and benign. Its symptoms are mild to moderate headache, loss of appetite, nausea, dizziness and insomnia. Nausea rarely progresses to vomiting, but if it does, this may anticipate a progression of the disease into the severe form of acute mountain sickness, called high altitude cerebral edema. Symptoms and signs of high altitude cerebral edema are severe headache, which is not relieved by acetaminophen, loss of movement coordination, ataxia and mental deterioration ending in coma. The mechanisms leading to acute mountain sickness are not very well understood; the loss of cerebral autoregulation and a vasogenic type of cerebral edema are being discussed. High altitude pulmonary edema presents in roughly twenty percent of the cases with mild symptoms of acute mountain sickness or even without any symptoms at all. Symptoms associated with high altitude pulmonary edema are incapacitating fatigue, chest tightness, dyspnoe at the minimal effort that advances to dyspnoe at rest and orthopnoe, and a dry non-productive cough that progresses to cough with pink frothy sputum due to hemoptysis. The hallmark of high altitude pulmonary edema is an exaggerated hypoxic pulmonary vasoconstriction. Successful prophylaxis and treatment of high altitude pulmonary edema using nifedipine, a pulmonary vasodilator, indicates that pulmonary hypertension is crucial for the development of high altitude pulmonary edema. The primary treatment of high altitude illness consists in improving hypoxemia and acclimatization. For prophylaxis a slow ascent at a rate of 300 m/day is recommended, if symptoms persist, acetazolamide at a

  17. Application of the Bow Tie method for evaluation of safety in the procedure of logging wells; Aplicacion del metodo de Bow Tie para la evaluacion de seguridad en la practica de perfilaje de pozos

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso Pallares, C; Perez Reyes, Y.; Sarabia Molina, I.I. [Centro Nacional de Seguridad Nuclear (CNSN), La Habana (Cuba)

    2013-07-01

    This work consists of an assessment of security in the practice of logging of oil wells, using the method of Bow Tie for being a simple method of evaluation of the risk, which makes it possible in a structured way to set priorities to manage risk.

  18. Digital mountains: toward development and environment protection in mountain regions

    Science.gov (United States)

    Jiang, Xiaobo

    2007-06-01

    Former studies on mountain system are focused on the department or subject characters, i.e. different department and branches of learning carry out researches only for their individual purposes and with individual characters of the subject of interests. As a whole, their investigation is lacking of comprehensive study in combination with global environment. Ecological environment in mountain regions is vulnerable to the disturbance of human activities. Therefore, it is a key issue to coordinate economic development and environment protection in mountain regions. On the other hand, a lot of work is ongoing on mountain sciences, especially depending on the application of RS and GIS. Moreover, the development of the Digital Earth (DE) provides a clue to re-understand mountains. These are the background of the emergence of the Digital Mountains (DM). One of the purposes of the DM is integrating spatial related data and information about mountains. Moreover, the DM is a viewpoint and methodology of understanding and quantifying mountains holistically. The concept of the DM is that, the spatial and temporal data related to mountain regions are stored and managed in computers; moreover, manipulating, analyzing, modeling, simulating and sharing of the mountain information are implemented by utilizing technologies of RS, GIS, GPS, Geo-informatic Tupu, computer, virtual reality (VR), 3D simulation, massive storage, mutual operation and network communication. The DM aims at advancing mountain sciences and sustainable mountain development. The DM is used to providing information and method for coordinating the mountain regions development and environment protection. The fundamental work of the DM is the design of the scientific architecture. Furthermore, construct and develop massive databases of mountains are the important steps these days.

  19. Oil and gas prospecting beneath Precambrian of Foreland thrust plates in Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Gries, R.

    1983-01-01

    Only 16 wells in the Rocky Mountain region have drilled through precambrian rocks to test the 3 to 6 million acres of sedimentary rocks concealed and virtually unexplored beneath mountain-front thrust. One recent test is a major gas discovery, another a development oil well, and over half of the unsuccessful tests had oil or gas shows. These wells have helped define the structural geometry of the mountain-front thrusts, including angle of the thrust, amount of horizontal displacement, and presence or absence of fault silvers containing overturned Mesozoic or Paleozoic rocks. Important for further geophysical exploration, these wells have provided data on seismic velocities in Precambrian rocks. Analysis of these data has stimulated further exploration along the fronts already drilled: in Wyoming, the Emigrant Trail, Washakie, and Wind River thrusts, the thrust at the north end of the Laramie Range, and the Casper arch; in Utah and Colorado, the Uncompahgre and Uinta uplits. The geologic success of these wells has encouraged leasing and seismic acquisition on every other mountain-front thrust in the Rockies. An unsuccessful attempt to drill through the Arlington thrust of the Medicine Bow Range will probably only momentarily daunt that play, and attempted penetration of the Axial arch in Colorado has not condemned that area; in fact, another well is being drilled at this time. Untested areas that will be explored in the near furture are: in Wyoming, south flank of the Owl Creek Range, southwest flank of the Gros Ventre Range, east and west flanks of the Big Horn Mountains, west flank of the Big Horn basin, north flank of the Hanna basin; in Utah, south flank of the Uinta Mountains; in Colorado, White River uplift, the north flank of North Park basin, and the Front Range.

  20. Oil and gas prospecting beneath Precambrian of foreland thrust plates in Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Gries, R.

    1983-01-01

    Only 16 wells in the Rocky Mountain region have drilled through Precambrian rocks to test the 3 to 6 million acres of sedimentary rocks that are concealed and virtually unexplored beneath mountain-front thrusts. One recent test is a major gas discovery, another a development oil well, and over half of the unsuccessful tests had oil or gas shows. These wells have not only set up an exciting play, they have also helped define the structural geometry of the mountain-front thrusts including the angle of the thrust, the amount of horizontal displacement, and the presence or absence of fault silvers containing overturned Mesozoic or Paleozoic rocks. Important for further geophysical exploration, these wells have provided vital data on seismic velocities in Precambrian rocks. Analysis of these data has stimulated further exploration along the fronts already drilled in Wyoming, the Emigrant Trail thrust, the Washakie thrust, the Wind River thrust, the thrust at the north end of the Laramie Range, and the Casper arch; in Utah and Colorado, the Uncompahgre and Uinta uplifts. The geologic success of these wells has encouraged leasing and seismic acquisition on every other mountain-front thrust in the Rockies. An unsuccessful attempt to drill through the Arlington thrust of the Medicine Bow Range will probably only momentarily daunt that play, and the attempted penetration of the Axial arch in Colorado has not condemned that area; in fact, another well is being drilled at this time. Untested areas that will be explored in the near future are: in Wyoming, the south flank of the Owl Creek Range, the southwest flank of the Gros Ventre Range, the east and west flanks of the Big Horn Mountains, the west flank of the Big Horn basin, the north flank of the Hanna basin; in Utah, the south flank of the Uinta Mountains; and in Colorado, the White River uplift, the north flank of North Park basin, and the Front Range.

  1. A Review of Density Holes Upstream of Earth's Bow Shock%A Review of Density Holes Upstream of Earth's Bow Shock

    Institute of Scientific and Technical Information of China (English)

    G K Parks; E Lee; N Lin; J B Cao; S Y Fu; J K Shi

    2011-01-01

    Larmor size transient structures with density depletions as large as 99% of ambient solar wind density levels occur commonly upstream of Earth's collisionless bow shock. These "density holes" have a mean duration of 17.9±10.4s but holes as short as 4 s have been observed. The average fractional density depletion (Sn/n) inside the holes is 0.68±0.14. The density of the upstream edge moving in the sunward direction can be enhanced by five or more times the solar wind density. Particle distributions show the steepened edge can behave like a shock, and measured local field geometries and Mach number support this view. Similarly shaped magnetic holes accompany the density holes indicating strong coupling between fields and particles. Current densities as large as 150 nA·m^-2 are observed at the leading compressed edge. The waves are elliptically polarized and rotating in the sense of ions (left hand) in the plasma frame. The waves appear to grow and steepen as the density holes convect with the solar wind toward the Earth. The transient nature of density holes suggests that the temporal features could represent the different stages of nonlinear evolutionary processes that produce a shock-like structure. The density holes are only observed with upstream particles, suggesting that back-streaming particles interacting with the solar wind are important. The significance of these observations is still being investigated.

  2. Analysis of Biomass Gasification Poisoning Accident Based on BN-bow-tie%基于BN-bow-tie的生物质气化中毒事故分析

    Institute of Scientific and Technical Information of China (English)

    闫放; 许开立; 姚锡文; 王延瞳

    2015-01-01

    通过将故障树转化为贝叶斯网络,计算生物质气化中毒事故发生的概率为1.202 98×10-4/d,利用贝叶斯网络双向推导与诊断的功能计算基本事件的后验概率及重要度,从而分析出系统中导致事故发生的薄弱环节.结合bow-tie法同时分析导致薄弱环节失效的因素及失效后可能会出现的后果,基于此得出防止薄弱环节失效的预防措施以及失效后采取的控制措施,进而降低事故发生的概率;对薄弱环节阀门泄漏采取措施后,可使得中毒事故发生概率降低20.92%,最终达到降低事故发生概率的目的.

  3. Two new species of the sharpshooter genus Oragua Melichar, 1926 from Southeastern Brazil (Hemiptera: Cicadellidae: Cicadellini).

    Science.gov (United States)

    Mejdalani, Gabriel; Silva, Cristiane M F Da; Takiya, Daniela M

    2016-01-01

    Two very similar new species of Oragua Melichar, 1926, O. linnavuorii sp. nov. and O. flavolineata sp. nov., are described and illustrated from the Atlantic Forest of Southeastern Brazil (Mantiqueira mountain range). The new species share the presence of a large dentiform process located posteroventrally on the male pygofer, a unique feature within the genus. They can be distinguished from each other by the paraphyses with a pair of elongate, slender asymmetrical rami in O. linnavuorii and with two pairs of short, spiniform apical processes in O. flavolineata. The male of O. linnavuorii is macropterous but the female is submacropterous and thus smaller than the former when specimens are measured from the apex of the crown to the tips of the forewings at rest. The female of O. flavolineata is not known. Male holotypes are deposited in DZRJ. A key to males of the five Oragua species recorded from Southeastern Brazil is provided [O. maculifera Young, 1977, O. discoidula (Osborn, 1926), O. triplehorni Young, 1977, O. linnavuorii, and O. flavolineata]. The superficially similar genera Oragua and Aguana Melichar, 1926 are briefly compared. PMID:27395683

  4. Two new species of the sharpshooter genus Oragua Melichar, 1926 from Southeastern Brazil (Hemiptera: Cicadellidae: Cicadellini).

    Science.gov (United States)

    Mejdalani, Gabriel; Silva, Cristiane M F Da; Takiya, Daniela M

    2016-01-01

    Two very similar new species of Oragua Melichar, 1926, O. linnavuorii sp. nov. and O. flavolineata sp. nov., are described and illustrated from the Atlantic Forest of Southeastern Brazil (Mantiqueira mountain range). The new species share the presence of a large dentiform process located posteroventrally on the male pygofer, a unique feature within the genus. They can be distinguished from each other by the paraphyses with a pair of elongate, slender asymmetrical rami in O. linnavuorii and with two pairs of short, spiniform apical processes in O. flavolineata. The male of O. linnavuorii is macropterous but the female is submacropterous and thus smaller than the former when specimens are measured from the apex of the crown to the tips of the forewings at rest. The female of O. flavolineata is not known. Male holotypes are deposited in DZRJ. A key to males of the five Oragua species recorded from Southeastern Brazil is provided [O. maculifera Young, 1977, O. discoidula (Osborn, 1926), O. triplehorni Young, 1977, O. linnavuorii, and O. flavolineata]. The superficially similar genera Oragua and Aguana Melichar, 1926 are briefly compared.

  5. Numerical Analysis of Interaction Between Single-Pulse Laser-Induced Plasma and Bow Shock in a Supersonic Flow

    Institute of Scientific and Technical Information of China (English)

    FANG Juan; HONG Yanji; LI Qian

    2012-01-01

    The interaction of laser-induced plasma and bow shock over a blunt body is inves- tigated numerically in an M∞ =6.5 supersonic flow. A ray-tracing method is used for simulating the process of laser focusing. The gas located at the focused zone is ionized and broken down and transformed into plasma. In a supersonic flow the plasma moves downstream and begins to interact with the bow shock when it approaches the surface of the blunt body. The parameters of flowfield and blunt body surface are changed due to the interaction. By analyzing phenomena occurring in the complex unsteady flowfield during the interaction in detail, we can better under- stand the change of pressure on the blunt body surface and the mechanism of drag reduction by laser energy deposition. The results show that the bow shock is changed into an oblique shock due to the interaction of the laser-induced low-density zone with the bow shock, so the wave drag of the blunt body is reduced.

  6. Is "Bow" for an Arrow or for Hair? A Classroom Demonstration on Gender Differences in Interpreting Ambiguous Information

    Science.gov (United States)

    Fa-Kaji, Naomi; Nguyen, Linda; Hebl, Mikki; Skorinko, Jeanine

    2016-01-01

    This article details a classroom demonstration of how gender differences in cognitive schemas can result in men and women differentially interpreting the same information. Students heard a series of six homonyms (e.g., bow and nail) spoken aloud and wrote down the first word with which they free-associated each homonym. When hearing the words…

  7. Role of In-segregation in anomalously large band-gap bowings of (In,Al,Ga)N

    DEFF Research Database (Denmark)

    Gorczyka, I.; Suski, T.; Christensen, Niels Egede;

    2011-01-01

    Large bowings of the band gap and its pressure coefficient in In-containing nitride semiconductor alloys are observed. Photoluminescence measurements for InxGa1-xN and InxAl1-xN combined with other experimental data show large scatter of the results. A comparison with ab-initio calculations sugge...

  8. Can the magnetic field in the Orion arm inhibit the growth of instabilities in the bow shock of Betelgeuse?

    CERN Document Server

    van Marle, Allard Jan; Meliani, Zakaria

    2013-01-01

    Many evolved stars travel through space at supersonic velocities, which leads to the formation of bow shocks ahead of the star where the stellar wind collides with the interstellar medium (ISM). Herschel observations of the bow shock of $\\alpha$-Orionis show that the shock is almost free of instabilities, despite being, at least in theory, subject to both Kelvin-Helmholtz and Rayleigh-Taylor instabilities. A possible explanation for the lack of instabilities lies in the presence of an interstellar magnetic field. We wish to investigate whether the magnetic field of the interstellar medium (ISM) in the Orion arm can inhibit the growth of instabilities in the bow shock of $\\alpha$-Orionis. We used the code MPI-AMRVAC to make magneto-hydrodynamic simulations of a circumstellar bow shock, using the wind parameters derived for $\\alpha$-Orionis and interstellar magnetic field strengths of $B\\,=\\,1.4,\\, 3.0$, and $5.0\\, \\mu$G, which fall within the boundaries of the observed magnetic field strength in the Orion arm ...

  9. Bow-tie risk assessment combining causes and effects applied to gasoil storage in an abandoned salt cavern,

    NARCIS (Netherlands)

    Visser, K; Hendriks, D.; Wildenborg, T.; Duijne, H.

    2014-01-01

    A semi-quantitative risk assessment is presented for the storage of gas oil in depleted salt caverns in the Twente region, the Netherlands. It is based on a bow-tie model, in which an incident, leakage of gas oil from the storage system (cavern and wells), is evaluated by assessing its possible caus

  10. Lateralization of horizontal semicircular canal canalolithiasis and cupulopathy using bow and lean test and head-roll test.

    Science.gov (United States)

    Kim, Chang-Hee; Kim, Yong Gyu; Shin, Jung Eun; Yang, Young Soo; Im, Donghyuk

    2016-10-01

    Accurate lateralization is important to improve treatment outcomes in horizontal semicircular canal (HSCC) benign paroxysmal positional vertigo (BPPV). To determine the involved side in HSCC-BPPV, the intensity of nystagmus has been compared in a head-roll test (HRT) and the direction of nystagmus was evaluated in a bow and lean test (BLT). The aim of this study is to compare the results of a BLT with those of a HRT for lateralization of HSCC-canalolithiasis and cupulopathy (heavy cupula and light cupula), and evaluate treatment outcomes in patients with HSCC-canalolithiasis. We conducted retrospective case reviews in 66 patients with HSCC-canalolithiasis and 63 patients with HSCC-cupulopathy. The affected side was identified as the direction of bowing nystagmus on BLT in 55 % (36 of 66) of patients with canalolithiasis, which was concordant with the HRT result in 67 % (24 of 36) of cases (concordant group). Lateralization was determined by comparison of nystagmus intensity during HRT in 30 patients who did not show bowing or leaning nystagmus. The remission rate after the first treatment was 71 % (17 of 24) in the concordant group and 45 % (5 of 11) in the discordant group. Both bowing and leaning nystagmus were observed in all patients with cupulopathy, and the side of the null plane was identified as the affected side. In conclusion, bowing and/or leaning nystagmus were observed in only 55 % of patients with HSCC-canalolithiasis, and the first treatment based on the result of BLT alone was effective in only 45 % of the patients in whom the BLT and HRT were discordant, which may suggest that the usefulness of BLT in lateralizing the HSCC-canalolithiasis may be limited.

  11. HIGH-TEMPERATURE PROCESSING OF SOLIDS THROUGH SOLAR NEBULAR BOW SHOCKS: 3D RADIATION HYDRODYNAMICS SIMULATIONS WITH PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    Boley, A. C. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Morris, M. A. [Center for Meteorite Studies, Arizona State University, P.O. Box 876004, Tempe, AZ 88287-6004 (United States); Desch, S. J. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States)

    2013-10-20

    A fundamental, unsolved problem in solar system formation is explaining the melting and crystallization of chondrules found in chondritic meteorites. Theoretical models of chondrule melting in nebular shocks have been shown to be consistent with many aspects of thermal histories inferred for chondrules from laboratory experiments; but, the mechanism driving these shocks is unknown. Planetesimals and planetary embryos on eccentric orbits can produce bow shocks as they move supersonically through the disk gas, and are one possible source of chondrule-melting shocks. We investigate chondrule formation in bow shocks around planetoids through three-dimensional radiation hydrodynamics simulations. A new radiation transport algorithm that combines elements of flux-limited diffusion and Monte Carlo methods is used to capture the complexity of radiative transport around bow shocks. An equation of state that includes the rotational, vibrational, and dissociation modes of H{sub 2} is also used. Solids are followed directly in the simulations and their thermal histories are recorded. Adiabatic expansion creates rapid cooling of the gas, and tail shocks behind the embryo can cause secondary heating events. Radiative transport is efficient, and bow shocks around planetoids can have luminosities ∼few× 10{sup –8} L{sub ☉}. While barred and radial chondrule textures could be produced in the radiative shocks explored here, porphyritic chondrules may only be possible in the adiabatic limit. We present a series of predicted cooling curves that merit investigation in laboratory experiments to determine whether the solids produced by bow shocks are represented in the meteoritic record by chondrules or other solids.

  12. Juvenile Cerebral Infarction Caused by Bow Hunter's Syndrome during Sport: Two Case Reports.

    Science.gov (United States)

    Kageyama, Hiroto; Yoshimura, Shinichi; Iida, Tomoko; Shirakawa, Manabu; Uchida, Kazutaka; Tomogane, Yusuke; Miyaji, Yuki

    2016-09-15

    We report two cases of juvenile cerebral infarction caused by bow hunter's syndrome (BHS) during sport. Case 1 was a 17-year-old male who developed a partial visual field defect after playing basketball. BHS was diagnosed because cervical ultrasonography demonstrated occlusion of the vertebral artery when the neck was rotated. After C1-2 posterior fixation was performed, his symptoms resolved. Case 2 was an 18-year-old male with recurrent visual disturbance after playing handball. Cerebral infarction occurred repeatedly despite antiplatelet therapy. After 3 years, vertebral artery dissection was diagnosed and stenting was performed, but his symptoms did not resolve. BHS was diagnosed when he was examined at our department. C1-2 posterior fixation was performed and his symptoms resolved. In these two cases, BHS was caused by sporting activity. For accurate diagnosis and treatment of BHS, neuroimaging with cervical rotation is mandatory. PMID:27053329

  13. Quantitative spectroscopy on individual wire, slot, bow-tie, rectangular, and square-shaped optical antennas.

    Science.gov (United States)

    Husnik, Martin; Niegemann, Jens; Busch, Kurt; Wegener, Martin

    2013-11-15

    By using a recently introduced approach combining a focus-modulation technique with a common-path interferometer, we measure quantitatively the extinction, scattering, and absorption cross-section spectra of individual optical antennas. The experimental results on thin-wire antennas, slot antennas, bow-tie antennas, rectangular antennas, and square-shaped antennas resonating at around 1.4 μm wavelength are discussed. We find increased resonant scattering cross sections for the latter four antennas compared to the thin-wire antenna, both in absolute terms and relative to the absorption cross section. The square-shaped antenna's resonant extinction cross section approaches the limit of a coherent point dipole. However, the ratio of the resonant extinction cross section to the geometrical cross section of 38 is largest for the simple thin-wire antenna.

  14. Pseudomorphic GeSn/Ge(001) quantum wells: Examining indirect band gap bowing

    Energy Technology Data Exchange (ETDEWEB)

    Tonkikh, Alexander A. [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); Institute for Physics of Microstructures RAS, GSP-105, Nizhniy Novgorod (Russian Federation); Eisenschmidt, Christian; Schmidt, Georg [Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3 D-01620, Halle (Saale) (Germany); Talalaev, Vadim G. [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); ZIK SiLi-Nano, Martin Luther University Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3 D-06120, Halle (Saale) (Germany); Zakharov, Nikolay D.; Werner, Peter [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); Schilling, Joerg [ZIK SiLi-Nano, Martin Luther University Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3 D-06120, Halle (Saale) (Germany)

    2013-07-15

    A study of the bandgap character of compressively strained GeSn{sub 0.060-0.091}/Ge(001) quantum wells grown by molecular beam epitaxy is reported. The built-in strain in GeSn wells leads to an increased separation between L and {Gamma} conduction band minima. The prevalent indirect interband transitions in GeSn were probed by photoluminescence spectroscopy. As a result we could simulate the L-valley bowing parameter in GeSn alloys, b{sub L} = 0.80 {+-} 0.06 eV at 10 K. From this we conclude that even compressively strained GeSn/Ge(001) alloys could become direct band gap semiconductors at the Sn-fraction higher than 17.0 at. %.

  15. Oxidation of graphene 'bow tie' nanofuses for permanent, write-once-read-many data storage devices.

    Science.gov (United States)

    Pearson, A C; Jamieson, S; Linford, M R; Lunt, B M; Davis, R C

    2013-04-01

    We have fabricated nanoscale fuses from CVD graphene sheets with a 'bow tie' geometry for write-once-read-many data storage applications. The fuses are programmed using thermal oxidation driven by Joule heating. Fuses that were 250 nm wide with 2.5 μm between contact pads were programmed with average voltages and powers of 4.9 V and 2.1 mW, respectively. The required voltages and powers decrease with decreasing fuse sizes. Graphene shows extreme chemical and electronic stability; fuses require temperatures of about 400 °C for oxidation, indicating that they are excellent candidates for permanent data storage. To further demonstrate this stability, fuses were subjected to applied biases in excess of typical read voltages; stable currents were observed when a voltage of 10 V was applied to the devices in the off state and 1 V in the on state for 90 h each. PMID:23478811

  16. Band gap bowing in NixMg1‑xO

    Science.gov (United States)

    Niedermeier, Christian A.; Råsander, Mikael; Rhode, Sneha; Kachkanov, Vyacheslav; Zou, Bin; Alford, Neil; Moram, Michelle A.

    2016-08-01

    Epitaxial transparent oxide NixMg1‑xO (0 ≤ x ≤ 1) thin films were grown on MgO(100) substrates by pulsed laser deposition. High-resolution synchrotron X-ray diffraction and high-resolution transmission electron microscopy analysis indicate that the thin films are compositionally and structurally homogeneous, forming a completely miscible solid solution. Nevertheless, the composition dependence of the NixMg1‑xO optical band gap shows a strong non-parabolic bowing with a discontinuity at dilute NiO concentrations of x  0.074 and account for the anomalously large band gap narrowing in the NixMg1‑xO solid solution system.

  17. Band gap bowing and electron localization of (GaxIn1-x)N

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byounghak; Wang, Lin-Wang

    2006-05-09

    The band gap bowing and the electron localization ofGaxIn1-xN are calculated using both the local density approximation (LDA)and screened-exchange local density functional (sX-LDA) methods. Thecalculated sX-LDA band gaps are in good agreement with the experimentallyobserved values, with errors of -0.26 and 0.09 eV for bulk GaN and InN,respectively. The LDA band gap errors are 1.33 and 0.81 eV for GaN andInN, in order. In contrast to the gap itself, the band gap bowingparameter is found to be very similar in sX-LDA and LDA. We identify thelocalization of hole states in GaxIn1-xN alloys along In-N-In chains. Thepredicted localizationis stronger in sX-LDA.

  18. On the proper Mach number and ratio of specific heats for modeling the Venus bow shock

    Science.gov (United States)

    Tatrallyay, M.; Russell, C. T.; Luhmann, J. G.; Barnes, A.; Mihalov, J. D.

    1984-01-01

    Observational data from the Pioneer Venus Orbiter are used to investigate the physical characteristics of the Venus bow shock, and to explore some general issues in the numerical simulation of collisionless shocks. It is found that since equations from gas-dynamic (GD) models of the Venus shock cannot in general replace MHD equations, it is not immediately obvious what the optimum way is to describe the desired MHD situation with a GD code. Test case analysis shows that for quasi-perpendicular shocks it is safest to use the magnetospheric Mach number as an input to the GD code. It is also shown that when comparing GD predicted temperatures with MHD predicted temperatures total energy should be compared since the magnetic energy density provides a significant fraction of the internal energy of the MHD fluid for typical solar wind parameters. Some conclusions are also offered on the properties of the terrestrial shock.

  19. From Bows to Sound-Chests: Tracing the Ancestry of the Violin

    Directory of Open Access Journals (Sweden)

    Janelle R. Finley

    2016-04-01

    Full Text Available The ancestry of the violin is a subject that has been studied, researched, debated, and written about in great detail. However, despite all of the research and study, the ancestry of the violin is still not certain. This paper presents two schools of thought that propose different theories as to how the ancestry of the violin should be determined and what instruments should be included in the ancestry of the violin. The first school of thought proposes that the violin’s ancestry should be traced through the bow. The second theory proposes that the violin’s ancestry should be traced through the sound-chest of the violin. This paper also presents the different arguments for and against each theory, the importance of this topic, and the paper’s position on this topic. Research for this paper was accomplished through the use of scholarly books on the subject of the history of the violin.

  20. Quantitative spectroscopy on individual wire, slot, bow-tie, rectangular, and square-shaped optical antennas.

    Science.gov (United States)

    Husnik, Martin; Niegemann, Jens; Busch, Kurt; Wegener, Martin

    2013-11-15

    By using a recently introduced approach combining a focus-modulation technique with a common-path interferometer, we measure quantitatively the extinction, scattering, and absorption cross-section spectra of individual optical antennas. The experimental results on thin-wire antennas, slot antennas, bow-tie antennas, rectangular antennas, and square-shaped antennas resonating at around 1.4 μm wavelength are discussed. We find increased resonant scattering cross sections for the latter four antennas compared to the thin-wire antenna, both in absolute terms and relative to the absorption cross section. The square-shaped antenna's resonant extinction cross section approaches the limit of a coherent point dipole. However, the ratio of the resonant extinction cross section to the geometrical cross section of 38 is largest for the simple thin-wire antenna. PMID:24322083

  1. On the origin of hot diamagnetic cavities near the earth's bow shock

    Science.gov (United States)

    Thomsen, M. F.; Gosling, J. T.; Bame, S. J.; Quest, K. B.; Russell, C. T.

    1988-01-01

    The origin of hot diamagnetic cavities (HDCs) observed occasionally upstream from the earth's bow shock is investigated by examining the results of November 16, 1977, observation, when four of these events occurred on a single day, as well as plasma and field data from that day. The results suggest that HDCs may form as a result of an unusually strong interaction between shock-reflected ions and the incoming solar wind. It is proposed that this interaction stems from a temporary and localized reflection of a larger-than-normal fraction of the incident ions, which is stimulated by sudden changes in the upstream field orientation; the consequences of such a temporary overreflection are found to be consistent with many of the observed features of HDCs, including the strong slowing, deflection, and heating of the flow, as well as the localization, internal recoveries, and occasional formation upstream from the shock itself.

  2. Observational evidence on the origin of ions upstream of the earth's bow shock

    Science.gov (United States)

    Thomsen, M. F.; Gosling, J. T.; Schwartz, S. J.

    1983-01-01

    The kinematic formalism described by Schwartz et al. (1983) is used to quantitatively compare the zeroth order predicted energies for four different source hypotheses for ions detected upstream of the earth's bow shock with previously published observations of upstream field-aligned beams and gyrating ion events. Specular reflection of a fraction of the incident solar wind is found to be the most credible explanation of gyrating ion events observed upstream of shocks ranging from quasi-parallel to nearly perpendicular. The recent hypothesis that field-aligned beams are the result of leakage from the magnetosheath of ions which were originally specularly reflected at quasi-perpendicular portions of the shock provides good agreement with observed energies of many field-aligned beams. Only magnetic moment conserving reflection of solar wind ions is capable of accounting for two very energetic beam events.

  3. Determination of main rational biomechanical characteristics in shooting from a bow

    Directory of Open Access Journals (Sweden)

    Adashevskiy V.M.

    2012-03-01

    Full Text Available The aim is to build rational parameters of technical actions of sportsman in shooting from a bow. It is worked out and decided mathematical model and the task of dynamics. Influence on having a special purpose exactness of corners of flight of arrow with an account and without the account of force of resistance of air environment is certain. It is distinguished the basic technical run-time errors of sportsman exercises. It is set that for successful realization of descriptions of target exactness and minimum values of deviations from an aim on different distances of shooting, sportsman must provide: maintenance of scene and rational pose, implementation of rational technical actions. It is shown directions of choice of necessary biomechanics descriptions that a sportsman can realize for providing target exactness and minimum values of deviations from aim on different distances of shooting.

  4. VASCULAR PLANTS OF SOUTHEASTERN OKLAHOMA FROM THE SANS BOIS TO THE KIAMICHI MOUNTAINS

    Directory of Open Access Journals (Sweden)

    Francis Hobart Means, Jr.

    2009-12-01

    Full Text Available The author grew up in the prairie region of Kay County where he learned to appreciate proper management of the soil and the native grass flora. After graduation from college, he moved to Eastern Oklahoma State College where he took a position as Instructor in Botany and Agronomy. In the course of conducting botany field trips and working with local residents on their plant problems, the author became increasingly interested in the flora of that area and of the State of Oklahoma. This led to an extensive study of the northern portion of the Oauchita Highlands with collections currently numbering approximately 4,200. The specimens have been processed according to standard herbarium procedures. The first set has been placed in the Herbarium of Oklahoma State University with the second set going to Eastern Oklahoma State College at Wilburton.

  5. Upward flow of magmatic fluids from the Old Woman granodiorite, Old Woman Mountains southeastern California

    Science.gov (United States)

    Morrison, Jean; Hoisch, Thomas D.

    1994-05-01

    Isotopic compositions, mineral equilibrium, and field relations at the contact between the midcrustal Cretaceous Old Woman granodiorite and Paleozoic carbonates indicate that water-rich, silica-saturated magmatic fluids were transported upward, away from the pluton, across an impermeable 30- to 40-m thick marble which caps the granodiorite, to higher structural levels along a complex network of hydrologically induced fractures. Within the fractures, fluids reacted to form symmetrical radiating splays of wollastonite with minor amounts of diopside, vesuvianite, and quartz. In many cases, pegmatites are found in the center of these calc-silicate skarns. Cross-cutting pegmatites and wollastonite veins in the aureole indicate that during late stages of crystallization of the granodiorite there were multiple episodes of fluid expulsion. Above the marble layer at higher structural levels, magmatic fluids flowed both laterally and vertically, interacting with lithologies in a more pervasive manner. Values of delta O-18 for calcite in the vein skarns average 11.8% and pegmatite whole rock silicate delta O-18 values average 9.4%. Thus oxygen isotopic compositions are consistent with a magmatic origin for the skarn-forming fluids. Away from the vein skarns, values of delta O-18 for the capping marble range from 18.7 to 22.1% (avg. = 21%) and values of delta C-13 range from -3.8 to -3.0% (avg. = -3.4%). The high delta O-18 values provide evidence that the marble largely retained its premetamorphic isotopic composition, indicating that fluids from the granodiorite did not flow pervasively across the unit. Lithologies at higher structural levels show evidence of more pervasive interaction with magmatic fluids: forsterite-bearing calc-silicates have delta O-18 values down to 11.8% and coarse-grained vesuvianite- and wollastonite-bearing skarns have delta O-18 values of approximately 13%.

  6. Hydrology of area 54, Northern Great Plains, and Rocky Mountain coal provinces, Colorado and Wyoming

    Science.gov (United States)

    Kuhn, Gerhard; Daddow, P.D.; Craig, G.S.; ,

    1983-01-01

    A nationwide need for information characterizing hydrologic conditions in mined and potential mine areas has become paramount with the enactment of the Surface Mining Control and Reclamation Act of 1977. This report, one in a series covering the coal provinces nationwide, presents information thematically by describing single hydrologic topics through the use of brief texts and accompanying maps, graphs, or other illustrations. The summation of the topical discussions provides a description of the hydrology of the area. Area 54, in north-central Colorado and south-central Wyoming, is 1 of 20 hydrologic reporting areas of the Northern Great Plains and Rocky Mountain coal provinces. Part of the Southern Rocky Mountains and Wyoming Basin physiographic provinces, the 8,380-square-mile area is one of contrasting geology, topography, and climate. This results in contrasting hydrologic characteristics. The major streams, the North Platte, Laramie, and Medicine Bow Rivers, and their principal tributaries, all head in granitic mountains and flow into and through sedimentary basins between the mountain ranges. Relief averages 2,000 to 3,000 feet. Precipitation in the mountains may exceed 40 inches annually, much of it during the winter, which produces deep snowpacks. Snowmelt in spring and summer provides most streamflow. Precipitation in the basins averages 10 to 16 inches annually, insufficient for sustained streamflow; thus, streams originating in the basins are ephemeral. Streamflow quality is best in the mountains where dissolved-solids concentrations generally are least. These concentrations increase as streams flow through sedimentary basins. The increases are mainly natural, but some may be due to irrigation in and adjacent to the flood plains. In the North Platte River, dissolved-solids concentrations are usually less than 300 milligrams per liter; in the Laramie and the Medicine Bow Rivers, the concentrations may average 500 to 850 milligrams per liter. However

  7. The CHESS survey of the L1157-B1 bow-shock: Dissecting the water content

    Science.gov (United States)

    Busquet, Gemma; Lefloch, Bertrand; Benedettini, Milena; Ceccarelli, Cecilia; Codella, Claudio; Cabrit, Sylvie; Nisini, Brunella; Viti, Serena; Gómez-Ruiz, Arturo; Gusdorf, Antoine; Di Giorgio, Anna Maria; Wiesenfeld, Laurent

    2013-07-01

    Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks, resulting in an increase of the abundance of several species. In particular, water is a powerful tracer of shocked material due to its sensitivity to both physical conditions and chemical processes. The observations of the "Chemical Herschel Survey of Star forming regions" (CHESS) key program towards the shock region L1157-B1 offered a unique and comprehensive view of the water emission in a typical protostellar bow shock across the submillimeter and far-infrared window. A grand total of 13 water lines have been detected with the PACS and HIFI instruments, probing a wide range of excitation conditions and providing us with a detailed picture on both the kinematics and the spatial distribution of water emission. Several gas components have been identified coexisting in the L1157-B1 shock region. Large Velocity Gradient (LVG) analysis reveals that these components have different excitation conditions: i) a warm (T~250 K) and dense (n(H2)~10^6 cm-3) gas component seen also with the CO lines and associated with the partly dissociative shock produced by the impact of the protostellar jet against the bow shock; ii) a compact (size~5''), hot (T~700 K), and less dense (n(H2)~10^4 cm-3) gas component, and iii) an extended component associated with the B1 outflow cavity. These three components present clear differences in terms of water enrichment. Finally, we confront the physical and chemical properties of the H2O emission to the predictions of current shock models.

  8. ION ACCELERATION AT THE QUASI-PARALLEL BOW SHOCK: DECODING THE SIGNATURE OF INJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, Torbjörn; Haynes, Christopher T.; Burgess, D. [School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS (United Kingdom); Mazelle, Christian X. [IRAP, Université Paul Sabatier Toulouse III-CNRS, 31028 Toulouse Cedex 4 (France)

    2016-03-20

    Collisionless shocks are efficient particle accelerators. At Earth, ions with energies exceeding 100 keV are seen upstream of the bow shock when the magnetic geometry is quasi-parallel, and large-scale supernova remnant shocks can accelerate ions into cosmic-ray energies. This energization is attributed to diffusive shock acceleration; however, for this process to become active, the ions must first be sufficiently energized. How and where this initial acceleration takes place has been one of the key unresolved issues in shock acceleration theory. Using Cluster spacecraft observations, we study the signatures of ion reflection events in the turbulent transition layer upstream of the terrestrial bow shock, and with the support of a hybrid simulation of the shock, we show that these reflection signatures are characteristic of the first step in the ion injection process. These reflection events develop in particular in the region where the trailing edge of large-amplitude upstream waves intercept the local shock ramp and the upstream magnetic field changes from quasi-perpendicular to quasi-parallel. The dispersed ion velocity signature observed can be attributed to a rapid succession of ion reflections at this wave boundary. After the ions’ initial interaction with the shock, they flow upstream along the quasi-parallel magnetic field. Each subsequent wavefront in the upstream region will sweep the ions back toward the shock, where they gain energy with each transition between the upstream and the shock wave frames. Within three to five gyroperiods, some ions have gained enough parallel velocity to escape upstream, thus completing the injection process.

  9. On nonstationarity and rippling of the quasiperpendicular zone of the Earth bow shock: Cluster observations

    Directory of Open Access Journals (Sweden)

    V. V. Lobzin

    2008-09-01

    Full Text Available A new method for remote sensing of the quasiperpendicular part of the bow shock surface is presented. The method is based on analysis of high frequency electric field fluctuations corresponding to Langmuir, upshifted, and downshifted oscillations in the electron foreshock. Langmuir waves usually have maximum intensity at the upstream boundary of this region. All these waves are generated by energetic electrons accelerated by quasiperpendicular zone of the shock front. Nonstationary behavior of the shock, in particular due to rippling, should result in modulation of energetic electron fluxes, thereby giving rise to variations of Langmuir waves intensity. For upshifted and downshifted oscillations, the variations of both intensity and central frequency can be observed. For the present study, WHISPER measurements of electric field spectra obtained aboard Cluster spacecraft are used to choose 48 crossings of the electron foreshock boundary with dominating Langmuir waves and to perform for the first time a statistical analysis of nonstationary behavior of quasiperpendicular zone of the Earth's bow shock. Analysis of hidden periodicities in plasma wave energy reveals shock front nonstationarity in the frequency range 0.33 fBiBi, where fBi is the proton gyrofrequency upstream of the shock, and shows that the probability to observe such a nonstationarity increases with Mach number. The profiles observed aboard different spacecraft and the dominating frequencies of the periodicities are usually different. Hence nonstationarity and/or rippling seem to be rather irregular both in space and time rather than resembling a quasiregular wave propagating on the shock surface.

  10. Post-irradiation examination of a bowed PWR fuel rod with contact

    International Nuclear Information System (INIS)

    During reactor operation in the Ringhals 2 PWR a fuel rod bowed and as a result came in contact with an adjacent rod. The rod contact in one of the lower grid spans was observed during visual inspection at the end of life. The visual appearance suggested that there was possibly increased cladding corrosion on both the contacting rods at and close to the position of contact. One of the contacting rods was sent to Studsvik’s Hot Cell Laboratory for investigation where fission gas analysis, gamma scanning, EC oxide thickness, metallography (optical microscopy) and cladding microhardness measurements were performed in order to verify the impact of the bow and the contact on the fuel rod performance, with particular focus on the local cladding corrosion. The influence of the reduction of moderator in the region of the contact point was seen in the Cs-137 axial gamma scanning and in the Ce-144 rotational gamma scanning, which show a local reduction of both the pellet-average power, in the contact region, and specifically on the side with the contact. Visual inspection revealed increased corrosion in the rod-rod contact position. Metallographic examination of a cross-section at the elevation with the contact showed that increased corrosion and loss of material had occurred at the contact position. Outside of the immediate vicinity of the contact region the corrosion was not affected. The cladding microhardness was measured at different radial positions both at the contact position and at other positions around the cladding circumference. Based on the relationship between the microhardness and local temperature during operation on fully wetted cladding, it was possible to estimate the cladding surface temperature at the contact point to approximately 360°C. This local overheating and conditions arising from the local overheating can explain the higher local oxidation of the cladding observed in the visual inspection and metallography. (author)

  11. Diffusive Shock Acceleration Simulations: Comparison with Particle Methods and Bow Shock Measurements

    Science.gov (United States)

    Kang, Hyesung; Jones, T. W.

    1995-07-01

    Direct comparisons of diffusive particle acceleration numerical simulations have been made against Monte Carlo and hybrid plasma simulations by Ellison et al. (1993) and against observations at the Earth's bow shock presented by Ellison et al. (1990). Toward this end we have introduced a new numerical scheme for injection of cosmic-ray particles out of the thermal plasma, modeled by way of the diffusive scattering process itself; that is, the diffusion and acceleration across the shock front of particles out of the suprathermal tail of the Maxwellian distribution. Our simulations take two forms. First, we have solved numerically the timedependent diffusion-advection equation for the high-energy (cosmic-ray) protons in one-dimensional quasiparallel shocks. Dynamical feedback between the particles and thermal plasma is included. The proton fluxes on both sides of the shock derived from our method are consistent with those calculated by Ellison et al. (1993). A similar test has compared our methods to published measurements at the Earth's bow shock when the interplanetary magnetic field was almost parallel to the solar wind velocity (Ellison et al. 1990). Again our results are in good agreement. Second, the same shock conditions have been simulated with the two-fluid version of diffusive shock acceleration theory by adopting injection rates and the closure parameters inferred from the diffusion-advection equation calculations. The acceleration efficiency and the shock structure calculated with the two-fluid method are in good agreement with those computed with the diffusion-advection method. Thus, we find that all of these computational methods (diffusion-advection, two-fluid, Monte Carlo, and hybrid) are in substantial agreement on the issues they can simultaneously address, so that the essential physics of diffusive particle acceleration is adequately contained within each. This is despite the fact that each makes what appear to be very different assumptions or

  12. Zoonotic Leprosy in the Southeastern United States.

    Science.gov (United States)

    Sharma, Rahul; Singh, Pushpendra; Loughry, W J; Lockhart, J Mitchell; Inman, W Barry; Duthie, Malcolm S; Pena, Maria T; Marcos, Luis A; Scollard, David M; Cole, Stewart T; Truman, Richard W

    2015-12-01

    Nine-banded armadillos (Dasypus novemcinctus) are naturally infected with Mycobacterium leprae and have been implicated in zoonotic transmission of leprosy. Early studies found this disease mainly in Texas and Louisiana, but armadillos in the southeastern United States appeared to be free of infection. We screened 645 armadillos from 8 locations in the southeastern United States not known to harbor enzootic leprosy for M. leprae DNA and antibodies. We found M. leprae-infected armadillos at each location, and 106 (16.4%) animals had serologic/PCR evidence of infection. Using single-nucleotide polymorphism variable number tandem repeat genotyping/genome sequencing, we detected M. leprae genotype 3I-2-v1 among 35 armadillos. Seven armadillos harbored a newly identified genotype (3I-2-v15). In comparison, 52 human patients from the same region were infected with 31 M. leprae types. However, 42.3% (22/52) of patients were infected with 1 of the 2 M. leprae genotype strains associated with armadillos. The geographic range and complexity of zoonotic leprosy is expanding. PMID:26583204

  13. Based on Bow-Tie Model of the Hanger Failure Analysis of Light-liner Cementing%基于Bow-Tie模型的轻尾管固井中悬挂器失效分析

    Institute of Scientific and Technical Information of China (English)

    孙泽秋; 金磊; 马锦明; 李强

    2015-01-01

    Light-liner Cementing is a dynamic systems with clearly technological process and com-plex construction.For failure research of light-liner hanger cementing process,the hanger failure of Bow-Tie model is constructed,which combine FTA with ETA analysis method.By using fault-tree analytic method,the failure reasons of hanger are induced in this paper,the failure cause of the accident after the whole process is studied,through event-tree analysis,which can understand light liner hanger cementing failure intuitively in the whole development process.Combined with certain oilfield accident analysis of Y well,Bow-Tie model is viable for the hanger failure issue based on the analysis of light-liner cementing.Studies show that Bow-Tie model is of great signifi-cance to prevent the hanger failure,and has a guiding significance for light-liner on-site cementing operation.%轻尾管固井是一个工艺流程清晰、施工较复杂的动态系统。针对轻尾管固井中的悬挂器失效问题,采用事故树和事件树相结合的分析方法,构建了悬挂器失效的Bow-Tie 模型。利用事故树分析法得到了诱发悬挂器失效的原因,通过事件树分析法研究了悬挂器失效后引起事故的全过程,直观地了解轻尾管固井中悬挂器失效的整个发展过程。结合某油田 Y 井的事故分析,验证了Bow-Tie模型在分析轻尾管固井中悬挂器失效方面是可行的。研究得出的悬挂器失效Bow-Tie模型对于防止悬挂器失效的发生具有重要意义,对于轻尾管固井的现场施工具有指导作用。

  14. Patient-centred mountain medicine.

    Science.gov (United States)

    Szawarski, Piotr; Hillebrandt, David

    2016-08-01

    Venturing into the mountains, doctors have accompanied expeditions to provide routine care to the teams, undertake research and occasionally take on a rescue role. The role of doctors practicing mountain medicine is evolving. Public health issues involving concepts of health and safety have become necessary with the coming of commercial and youth expeditions. Increasingly individuals with a disability or a medical diagnosis choose to ascend to high altitudes. Doctors become involved in assessment of risk and providing advice for such individuals. The field of mountain medicine is perhaps unique in that acceptance of risk is part of the ethos of climbing and adventure. The pursuit of mountaineering goals may represent the ultimate conquest of a disability. Knowledge of mountain environment is essential in facilitating mountain ascents for those who choose to undertake them, in spite of a disability or medical condition. PMID:27234206

  15. A Breath of Mountain Air

    Institute of Scientific and Technical Information of China (English)

    YU LINTAO

    2011-01-01

    Mountains are everywhere,and rivers flow in almost every valley.This is the Qinling Mountains,a major eastto-west range in southern Shaanxi Province,bordering Hubei and Henan provinces.Because of its huge forest coverage,the Qinling Mountains are also known as one of the lungs of China.Expectations for travelling are changing in China as the lifestyle of city dwellers has become fast-paced and demanding.That provides the Qirding Mountain area a great opportunity to develop leisure tourism.

  16. An analysis of a typical bow echo%一次下击暴流显著弓形回波特征

    Institute of Scientific and Technical Information of China (English)

    李胜山; 张殿江; 胡玲; 吴强; 于莉莉

    2012-01-01

    利用天气图、卫星云图和天津新一代天气雷达资料对2007年7月31日凌晨发生在蓟县的强风过程进行分析。结果表明:此次过程是弓形回波与超级单体在合并过程中产生的下击暴流过程而并非龙卷过程。2007年7月30日夜间至31日凌晨,一条自西南向东北方向移动的弓形回波,先后影响天津地区的6个区县产生雷阵雨短时暴雨天气,最大雨强为37.6 mm.h-1,但6个气象站均未出现飑、冰雹和地面大风。对连续观测的雷达资料分析发现,反射率因子图上,显示一条维持了5 h多的弓形回波在移动过程中与一个预先存在低质心的超级单体在蓟县山区合并,产生了下击暴流;反射率因子图上弱回波缺口出现;同时弓形回波形态发生改变,2.4°仰角以上产生断裂;最大雷达反射率因子为53 dBz。在相对径向速度图上,早期呈现为明显的后侧入流急流,后期有中气旋生成并伴有中低层辐散;高层出现强反气旋特征。风暴发展高度较高,回波顶高超过15 km,随着下击暴流的发生,反射率因子核有一个3 km的急降。%Based on the weather charts,satellite cloud images and the new generation weather radar data,a strong wind process on July 31,2007 was analyzed.The results indicate that the process is downburst but not tornadoes,and it is produced by the merger process of the bow echo and supercell.A bow echo moves from southwest to northeast during the night on July 30 to wee hours on July 31,2007,and it makes six districts and counties of Tianjin generating thunder shower and short-time rainstorm.The maximum precipitation intensity reaches 37.6 mm · h-1,while squall,hail and ground gale do not occur in six weather stations.By analyzing the radar data,it shows that the moving bow echo maintaining more than 5 hours merges with a pre-existing supercell in mountain area of Jixian and produces downburst.The weak echo region gap appears in the reflectivity

  17. "Christ is the Mountain"

    Directory of Open Access Journals (Sweden)

    Carl Hallencreutz

    1979-01-01

    Full Text Available In this paper the author focuses on the religious function of symbols in the encounter and interaction of Christianity and other religions. Some observations on the religious function of the symbol of the Holy Mountain in different African contexts are presented. These contexts are a traditional Kikuyu religion, b a Christian hymn from Northern Tanzania, and c the New Year's Fiest of the independent Nazaretha Church among Zulu in South Africa. The examples of how the symbol of the holy mountain is used in different religious contexts in Africa are, of course, too limited to provide a basis for far-reaching generalizations on how symbols function religiously in the encounter of Christianity and other religions. However, this kind of analysis can be applied also when studying other encounters of religions inside and outside Africa. The symbol functions both as a carrier of a new religious message and as an indigenous means to appropriate this message locally and give it adequate form in different milieus. The symbols, which most likely have the religious functions are those which are of a general nature; light, way, living water, and which some are tempted to speak of as archetypes. Yet the comparison between the Chagga-hymn to the holy mountain and Shembe's interpretation of the blessing of the New Year's Fiest on Inhlangakozi indicates, that in the encounter of Christianity and other religions it is not only the symbols as such which produce the local appropriation of the new religious message and give it adequate localized form. Not even in the encounter of Christianity and other religions the symbols function religiously without human beings as actors in the historical process.

  18. Major results of gravity and magnetic studies at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    About 4000 gravity stations have been obtained at Yucca Mountain and vicinity since the beginning of radioactive-waste studies there in 1978. These data have been integrated with data from about 29,000 stations previously obtained in the surrounding region to produce a series of Bouguer and isostatic-residual-gravity maps of the Nevada Test Site and southeastern Nevada. Yucca Mountain is characterized by a WNW-dipping gravity gradient whereby residual values of -10 mGal along the east edge of Yucca Mountain decrease to about -38 mGal over Crater Flat. Using these gravity data, two-dimensional modeling predicted the depth to pre-Cenozoic rocks near the proposed repository to be about 1220 ± 150 m, an estimate that was subsequently confirmed by drilling to be 1244 m. Three-dimensional modeling of the gravity low over Crater Flat indicates the thickness of Cenozoic volcanic rocks and alluvial cover to be about 3000 m. Considerable aeromagnetic coverage of southwestern Nevada was obtained in 1978--1979 to help characterize Yucca Mountain and vicinity. One significant result is the discovery of a series of circular magnetic anomalies in Crater Flat and the northern Amargosa Desert that suggest the presence of buried volcanic centers there. Elongate magnetic highs and associated lows over Yucca Mountain correlate with mapped faults, some of which are only partially exposed. Thus, the data provide inforamtion on the extent and continuity of these faults. 31 refs., 3 figs

  19. MODIS-based air temperature estimation in the southeastern Tibetan Plateau and neighboring areas

    Institute of Scientific and Technical Information of China (English)

    YAO Yonghui; ZHANG Baiping

    2012-01-01

    Climatic conditions are difficult to obtain in high mountain regions due to few meteorological stations and,if any,their poorly representative location designed for convenient operation.Fortunately,it has been shown that remote sensing data could be used to estimate near-surface air temperature (Ta) and other climatic conditions.This paper makes use of recorded meteorological data and MODIS data on land surface temperature (Ts) to estimate monthly mean air temperatures in the southeastern Tibetan Plateau and its neighboring areas.A total of 72 weather stations and 84 MODIS images for seven years (2001 to 2007) are used for analysis.Regression analysis and spatio-temporal analysis of monthly mean Ts vs.monthly mean Ta are carried out,showing that recorded Ta is closely related to MODIS Ts in the study region.The regression analysis of monthly mean Ts vs.Ta for every month of all stations shows that monthly mean Ts can be rather accurately used to estimate monthly mean Ta (R2 ranging from 0.62 to 0.90 and standard error between 2.25 ℃ and 3.23℃).Thirdly,the retrieved monthly mean Ta for the whole study area varies between 1.62℃ (in January,the coldest month) and 17.29 ℃ (in July,the warmest month),and for the warm season (May-September),it is from 13.1 ℃ to 17.29℃.Finally,the elevation of isotherms is higher in the central mountain ranges than in the outer margins; the 0℃ isotherm occurs at elevation of about 4500±500 m in October,dropping to 3500±500 m in January,and ascending back to 4500±500 m in May next year.This clearly shows that MODIS Ts data combining with observed data could be used to rather accurately estimate air temperature in mountain regions.

  20. 基于模糊Bow-tie模型的深水海底管道定量风险评价研究%Quantitative Risk Assessment of Deepwater Submarine Pipeline Based on Fuzzy Bow-tie Model

    Institute of Scientific and Technical Information of China (English)

    胡显伟; 段梦兰; 官耀华

    2012-01-01

    In order to effectively assess risk of deepwater submarine pipeline, a new quantitative risk assessment method based on fuzzy bow - tie model, was therefore proposed. Firstly, leakage possibility of oil/gas was quantitatively analyzed using Bow-tie model, Fuzzy Sets and Delphi method. Moreover, leakage consequence was analyzed by analytic hierarchy process, and weighting coefficients of consequence-influencing factors were obtained. Accordingly, quantitative risk assessment was completed by risk matrix. In the end, the above-mentioned assessment method was applied to a certain submarine pipeline. Leakage possibility level of target submarine pipeline belongs to A and leakage consequence level, Ⅲ, and risk level , high, agreeing well with the reality.%为有效评价深水海底管道风险,提出一种新的模糊Bow-tie模型定量风险评价方法.综合运用Bow-tie图、模糊集以及德尔菲法,定量分析油气泄漏概率.进一步利用层次分析法(AHP)研究油气泄漏后果的严重程度,给出泄漏后果因素的权重系数选择方案.同时,结合风险矩阵,实现对高风险深水海底管道的定量风险评价.将上述方法用到具体海底管道工程中,得出目标海底管道泄漏概率属于A级,泄漏后果属于Ⅲ级,泄漏风险为高风险,这一结果与实际情况较为符合.

  1. Human impacts to mountain streams

    Science.gov (United States)

    Wohl, Ellen

    2006-09-01

    Mountain streams are here defined as channel networks within mountainous regions of the world. This definition encompasses tremendous diversity of physical and biological conditions, as well as history of land use. Human effects on mountain streams may result from activities undertaken within the stream channel that directly alter channel geometry, the dynamics of water and sediment movement, contaminants in the stream, or aquatic and riparian communities. Examples include channelization, construction of grade-control structures or check dams, removal of beavers, and placer mining. Human effects can also result from activities within the watershed that indirectly affect streams by altering the movement of water, sediment, and contaminants into the channel. Deforestation, cropping, grazing, land drainage, and urbanization are among the land uses that indirectly alter stream processes. An overview of the relative intensity of human impacts to mountain streams is provided by a table summarizing human effects on each of the major mountainous regions with respect to five categories: flow regulation, biotic integrity, water pollution, channel alteration, and land use. This table indicates that very few mountains have streams not at least moderately affected by land use. The least affected mountainous regions are those at very high or very low latitudes, although our scientific ignorance of conditions in low-latitude mountains in particular means that streams in these mountains might be more altered than is widely recognized. Four case studies from northern Sweden (arctic region), Colorado Front Range (semiarid temperate region), Swiss Alps (humid temperate region), and Papua New Guinea (humid tropics) are also used to explore in detail the history and effects on rivers of human activities in mountainous regions. The overview and case studies indicate that mountain streams must be managed with particular attention to upstream/downstream connections, hillslope

  2. Bowing and expansion of natural stone panels: marble and limestone testing and assessment

    Directory of Open Access Journals (Sweden)

    Grelk, Bent

    2008-06-01

    Full Text Available Natural stone has been used as a building material for centuries. In the past, load bearing members were made of entirely of stone, but in the last 50 years new processing techniques have made the production and use of thin facade cladding a profitable venture. Unfortunately however, marble facades on buildings in Europe and elsewhere have undergone severe deterioration. The EC-financed TEAM project (2000-2005 studied the bowing observed on marble facades in both cold and warm climates. TEAM’s main objectives were to understand and explain the expansion, bowing, and strength loss mechanisms governing the decay of marble- and limestone-clad facades, and to draft new European standards to prevent the use of marble and limestone poorly suited to outdoor cladding. A survey of some 200 buildings afforded a clear picture of the geographical, geological and climatic scope of the problem. Detailed case studies of six buildings resulted in a facade assessment methodology that included a monitoring system and risk assessment. Both laboratory and field research was conducted on almost 100 different types of stone from different countries and in place in different climates. The outcome was the determination of the decay mechanisms and critical factors. Two test methods and respective precision statements, one for bowing and the other for irreversible thermal expansion in high humidity conditions, were prepared for submission to CEN TC 246.La piedra natural se ha empleado como material de construcción durante siglos. En el pasado, se solía utilizar en elementos de carga, pero en los últimos 50 años las nuevas técnicas de procesamiento han permitido que sea comercialmente rentable producir y utilizar revestimientos para fachadas de espesor reducido. Desafortunadamente, numerosas fachadas de mármol de edificios tanto en Europa como fuera de ella han sufrido graves problemas derivados del deterioro de la piedra. El proyecto TEAM (2000

  3. Protection layer analysis based on bow-tie applying in risk analysis%基于bow-tie的保护层分析法在风险分析中的应用研究

    Institute of Scientific and Technical Information of China (English)

    王旭; 张可旺

    2015-01-01

    充分考虑石化装置的复杂工艺特点,建立了基于领结分析(bow-tie)的保护层(LOPA)风险分析法,能够在相互关联的工艺装置体系中,明确“关系”并客观的进行量化分析.首先运用HAZOP辨识工艺过程中的危险,并对识别出的危险所导致的事故后果进行定性评估,找出事故后果等级较高的危险;然后运用bow-tie-LOPA集成分析对该风险的关键事件进行全面分析,确定事故可能发生的概率,以及保护措施是否将风险降低到可接受水平;若剩余风险等级超过容许标准,则需进行bow-tie分析辨识出使保护层持续有效的关键活动,进而控制后果严重事故的发生.

  4. Application of Bow-tie Technology in the Risk Management of Urban Gas Pipeline%Bow-tie技术在城镇燃气管道风险管理中的应用

    Institute of Scientific and Technical Information of China (English)

    贾朋美; 於孝春; 宋前甫

    2014-01-01

    为完善燃气管道安全评价体系,首次将Bow-tie技术引入到城镇燃气管道的风险管理中,通过Bow-tie图将故障树与事件树结合起来,定性分析了导致燃气管道泄漏的原因和后果,针对性地提出预防减缓措施.Bow-tie技术将风险辨识、风险分析、风险评估、风险控制和风险管理在图形中完整地展现出来,具有广泛的适用性,既可用于事前预防,又能指导事后响应,最大程度杜绝管道事故的发生,为燃气管道完整性管理提供实用的技术支撑.

  5. Dual-Frequency Operation of Bow-Tie Microstrip Antenna%蝶形微带天线的双频工作

    Institute of Scientific and Technical Information of China (English)

    钟顺时; 张需溥

    2005-01-01

    Characteristics of a single-feed dual-frequency bow-tie microstrip antenna are studied. By using the variation method, simple formulas for resonant frequencies of the bow-tie microstrip antenna are derived. It is shown that the dual-frequency ratio can be controlled easily by choosing the parameters of the antenna. This design gives compact antenna size and simple antenna structure. Experimental results are presented, verifying the validity of the design.

  6. Study on the effect of the CANFLEX-NU fuel element bowing on the critical heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Suk, Ho Chun; Cho, Moon Sung; Jeon, Ji Su

    2001-01-01

    The effect of the CANFLEX-NU fuel element bowing on the critical heat flux is reviewed and analyzed, which is requested by KINS as the Government design licensing condition for the use of the fuel bundles in CANDU power reactors. The effect of the gap between two adjacent fuel elements on the critical heat flux and onset-of-dryout power is studied. The reduction of the width of a single inter-rod gap from its nominal size to the minimum manufacture allowance of 1 mm has a negligible effects on the thermal-hydraulic performance of the bundle for the given set of boundary conditions applied to the CANFLEX-43 element bundle in an uncrept channel. As expected, the in-reactor irradiation test results show that there are no evidence of the element bow problems on the bundle performance.

  7. Band gap bowings and anomalous pressure effects in III–V nitride alloys: Role of In-segregation

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede;

    2011-01-01

    Using ab initio calculations a comparison between InxGa1-xN, InxAl1-xN and GaxAl1-xN is performed to examine the role of indium in nitride alloys. The band gap, Eg, as well as its pressure coefficient, dEg/dp, are studied as functions of chemical composition, x. Following theoretical and...... experimental suggestions about the crucial role of In-segregation in InxGa1-xN and InxAl1-xN, different arrangements of In atoms, uniform and clustered are considered. The presence of In and its clustering introduces a significant reduction of both Eg and dEg/dp, as well as strong bowings. These effects are...... responsible for the enhancements of bowings in the case of clustered distribution of indium atoms....

  8. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

    Science.gov (United States)

    Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

    2015-01-01

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch. PMID:26690443

  9. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    Directory of Open Access Journals (Sweden)

    Seung-Hyun Eom

    2015-12-01

    Full Text Available In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT switch and a balun element. A double-sided parallel-strip line (DSPSL is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  10. X-ray Observations of Bow Shocks around Runaway O Stars. The case of $\\zeta$ Oph and BD+433654

    CERN Document Server

    Toalá, J A; González-Gaán, A; Guerrero, M A; Ignace, R; Pohl, M

    2016-01-01

    Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations towards the runaway stars $\\zeta$ Oph (Chandra and Suzaku) and BD+433654 (XMM-Newton) to search for the presence of non-thermal X-ray emission. We found no evidence of non-thermal emission spatially coincident with the bow shocks, nonetheless, diffuse emission is detected in the vicinity of $\\zeta$ Oph. After a careful analysis of its spectral characteristics we conclude that this emission has a thermal nature with a plasma temperature of $T \\approx 2 \\times10^{6}$ K. The cometary shape of this emission seems to be in line with recent predictions of radiation-hydrodynamic models of runaway stars. The case of BD+433654 is puzzling as non-thermal emission has been reported in a previous work for this source.

  11. Band gap energy and bowing parameter of In-rich InAlN films grown by magnetron sputtering

    International Nuclear Information System (INIS)

    The crystal structure, band gap energy and bowing parameter of In-rich InxAl1-xN (0.7 xAl1-xN films were obtained from absorption spectra. Band gap tailing due to compositional fluctuation in the films was observed. The band gap of the as-grown InN measured by optical absorption method is 1.34 eV, which is larger than the reported 0.7 eV for pure InN prepared by molecular beam epitaxy (MBE) method. This could be explained by the Burstein-Moss effect under carrier concentration of 1020 cm-3 of our sputtered films. The bowing parameter of 3.68 eV is obtained for our InxAl1-xN film which is consistent with the previous experimental reports and theoretical calculations.

  12. Enhanced diffusive ion scattering in front of the Earth's quasi-parallel bow shock: a case study

    Science.gov (United States)

    Kis, Arpad; Scholer, Manfred; Klecker, Berndt; Lucek, Elisabeth; Dandouras, Iannis; Lemperger, István; Wesztergom, Viktor; Novák, Attila; Szalai, Sándor

    2014-05-01

    In our study we report on observations of energetic ions upstream of the Earth's quasi-parallel bow shock by Cluster at times of large inter-spacecraft separation distance. For the analysis we use the ion data provided by the CIS-HIA in the 10-32 keV energy range and the magnetic data recorded by the FGM instrument. We determine the spatial gradient of partial energetic ion densities at various distances from the bow shock. The gradient in all energy channels decreases exponentially with distance and the e-folding distance of the gradients depends approximately linearly on energy but there is a significant difference in their values obtained at the observed three upstream ion events. We demonstrate for the first time that under specific interplanetary conditions the mechanism of the diffuse ion scattering can change significantly and results in an anomalous diffusive process charactized by an unusually small e-folding distance.

  13. Non-thermal X-rays from bow shock runaways: a legacy programme for XMM-Newton

    Science.gov (United States)

    De Becker, Michael

    2013-10-01

    Massive stars ejected from their birth place, the so-called runaway massive stars, are likely to produce strong bow shocks through the interaction of the their stellar winds with the interstellar medium. Such shocks have been proven to be efficient at accelerating particles, as revealed by the identification of non-thermal radiation in a couple of objects. This large programme aims at obtaining measurements of the non-thermal X-ray flux of a carefully selected sample of bow shock runaways (BSRs), to quantify their capability to accelerate particles, in relation with their potential contribution to the production of Galactic cosmic-rays. Such an unprecedented collection of data is aimed at constituting some kind of legacy programme for XMM-Newton, before the advent of future generation X-ray observatories.

  14. Fire history of southeastern Glacier National Park: Missouri River Drainage

    Science.gov (United States)

    Barrett, Stephen W.

    1993-01-01

    In 1982, Glacier National Park (GNP) initiated long-term studies to document the fire history of all forested lands in the 410,000 ha. park. To date, studies have been conducted for GNP west of the Continental Divide (Barrett et al. 1991), roughly half of the total park area. These and other fire history studies in the Northern Rockies (Arno 1976, Sneck 1977, Arno 1980, Romme 1982, Romme and Despain 1989, Barrett and Arno 1991, Barrett 1993a, Barrett 1993b) have shown that fire history data can be an integral element of fire management planning, particularly wen natiral fire plans are being developed for parks and wilderness. The value of site specific fire history data is apparent when considering study results for lodgepole pin (Pinus contorta var. latifolia) forests. Lodgepole pine is a major subalpine type in the Northern Rockies and such stands experiences a wide range of presettlement fire patterns. On relatively warm-dry sites at lower elevations, such as in GNP's North Fork drainage (Barrett et al. 1991), short to moderately long interval (25-150 yr) fires occurred in a mixed severity pattern ranging from non-lethal underburns to total stand replacement (Arno 1976, Sneck 1977, Barrett and Arno 1991). Markedly different fire history occurred at high elevation lodgepole pine stands on highly unproductive sites, such as on Yellowstone National Park's (YNP) subalpine plateau. Romme (1982) found that, on some sites, stand replacing fires recurred after very long intervals (300-400 yr), and that non-lethal surface fires were rare. For somewhat more productive sites in the Absaroka Mountains in YNP, Barrett (1993a) estimated a 200 year mean replacement interval, in a pattern similar to that found in steep mountain terrain elsewhere, such as in the Middle Fork Flathead River drainage (Barrett et al. 1991, Sneck 1977). Aside from post-1900 written records (ayres 1900; fire atlas data on file, GNP Archives Div. and GNP Resources Mgt. Div.), little fire history

  15. Dispersion of low frequency plasma waves upstream of the quasi-perpendicular terrestrial bow shock

    Directory of Open Access Journals (Sweden)

    A. P. Dimmock

    2013-08-01

    Full Text Available Low frequency waves in the foot of a supercritical quasi-perpendicular shock front have been observed since the very early in situ observations of the terrestrial bow shock (Guha et al., 1972. The great attention that has been devoted to these type of waves since the first observations is explained by the key role attributed to them in the processes of energy redistribution in the shock front by various theoretical models. In some models, these waves play the role of the intermediator between the ions and electrons. It is assumed that they are generated by plasma instability that exist due to the counter-streaming flows of incident and reflected ions. In the second type of models, these waves result from the evolution of the shock front itself in the quasi-periodic process of steepening and overturning of the magnetic ramp. However, the range of the observed frequencies in the spacecraft frame are not enough to distinguish the origin of the observed waves. It also requires the determination of the wave vectors and the plasma frame frequencies. Multipoint measurements within the wave coherence length are needed for an ambiguous determination of the wave vectors. In the main multi-point missions such as ISEE, AMPTE, Cluster and THEMIS, the spacecraft separation is too large for such a wave vector determination and therefore only very few case studies are published (mainly for AMPTE UKS AMPTE IRM pair. Here we present the observations of upstream low frequency waves by the Cluster spacecraft which took place on 19 February 2002. The spacecraft separation during the crossing of the bow shock was small enough to determine the wave vectors and allowed the identification of the plasma wave dispersion relation for the observed waves. Presented results are compared with whistler wave dispersion and it is shown that contrary to previous studies based on the AMPTE data, the phase velocity in the shock frame is directed downstream. The consequences of this

  16. Quantified Energy Dissipation Rates in the Terrestrial Bow Shock. 2; Waves and Dissipation

    Science.gov (United States)

    Wilson, L. B., III; Sibeck, D. G.; Breneman, A. W.; Le Contel, O.; Cully, C.; Turner, D. L.; Angelopoulos, V.; Malaspina, D. M.

    2014-01-01

    We present the first quantified measure of the energy dissipation rates, due to wave-particle interactions, in the transition region of the Earth's collision-less bow shock using data from the Time History of Events and Macro-Scale Interactions during Sub-Storms spacecraft. Our results show that wave-particle interactions can regulate the global structure and dominate the energy dissipation of collision-less shocks. In every bow shock crossing examined, we observed both low-frequency (less than 10 hertz) and high-frequency (approximately or greater than10 hertz) electromagnetic waves throughout the entire transition region and into the magnetosheath. The low-frequency waves were consistent with magnetosonic-whistler waves. The high-frequency waves were combinations of ion-acoustic waves, electron cyclotron drift instability driven waves, electrostatic solitary waves, and whistler mode waves. The high-frequency waves had the following: (1) peak amplitudes exceeding delta B approximately equal to 10 nanoteslas and delta E approximately equal to 300 millivolts per meter, though more typical values were delta B approximately equal to 0.1-1.0 nanoteslas and delta E approximately equal to 10-50 millivolts per meter (2) Poynting fluxes in excess of 2000 microWm(sup -2) (micro-waves per square meter) (typical values were approximately 1-10 microWm(sup -2) (micro-waves per square meter); (3) resistivities greater than 9000 omega meters; and (4) associated energy dissipation rates greater than 10 microWm(sup -3) (micro-waves per cubic meter). The dissipation rates due to wave-particle interactions exceeded rates necessary to explain the increase in entropy across the shock ramps for approximately 90 percent of the wave burst durations. For approximately 22 percent of these times, the wave-particle interactions needed to only be less than or equal to 0.1 percent efficient to balance the nonlinear wave steepening that produced the shock waves. These results show that wave

  17. Mountains and Tropical Circulation

    Science.gov (United States)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  18. Protected areas in mountains

    Directory of Open Access Journals (Sweden)

    Hamilton, L. S.

    2006-12-01

    Full Text Available

    The importance of a global Protected Areas Network in sustaining appropriate mountain development is presented in this paper. Present status of the world’s “official” Protected Areas in the UN List, and the proportion that are in mountain areas, and including international designations (World Heritage and Biosphere Reserves. Current and future challenges in the management of these special areas are also commented.



    El autor destaca la importancia de una Red Mundial de Espacios Protegidos para el desarrollo sostenible de las montañas. Comenta luego el estatus actual de las Áreas Protegidas “oficiales” del Mundo en la Lista de las Naciones Unidas y qué proporción de ellas forma parte de las montañas, sin olvidar las figuras internacionales de protección como Patrimonio de la Humanidad y Reservas de Biosfera. Para terminar, se discuten los problemas de gestión actuales y futuros de estas áreas tan especiales

  19. Bow shock studies at Mercury, Venus, Earth, and Mars with applications to the solar-planetary interaction problem

    International Nuclear Information System (INIS)

    A series of bow shock studies conducted for the purpose of investigating the interaction between the solar wind and the terrestrial planets is presented. Toward this end appropriate modeling techniques have been developed and applied to the bow wave observations at Venus, Earth, and Mars. For Mercury the measurements are so few in number that no accurate determination of shock shape was deemed possible. Flow solutions generated using the observed bow wave surface as a boundary condition in a single fluid variable obstacle shape gasdynamic model produced excellent fits to the measured width and shape of the earth's magnetosheath. This result and the observed ordering of shock shape and position by upstream sonic Mach number provide strong support for the validity of the gasdynamic approximation. At Mercury the application of earth type models to the individual Mariner 10 boundry crossings has led to the determination of an effective planetary magnetic moment of 6+-2 x 1022 G-cm3. Consistent with the presence of a small terrestrial style magnetosphere, southward interplanetary magnetic fields were found to significantly reduce the solar wind stand-off distance most probably through the effects of dayside magnetic reconnection. For Venus the low altitude solar wind flow field derived from gasdynamic modeling of bow shock location and shape indicates that a fraction of the incident streamlines are absorbed by the neutral atmosphere near the ionopause; approximately 1% and 8%, respectively, in the solar maximum Pioneer Venus and solar minimum Venera measurements. Accordingly, it appears that cometary processes must be included in model calculations of the solar wind flow about Venus. At Mars the moderate height of the gasdynamic solar wind-obstacle interface and the weakness of the Martian ionosphere/atmosphere are found to be incompatible with a Venus type interaction

  20. Bond order wave (BOW) phase of the extended Hubbard model: Electronic solitons, paramagnetism, coupling to Peierls and Holstein phonons

    OpenAIRE

    Kumar, Manoranjan; Soos, Zolt'an G.

    2011-01-01

    The bond order wave (BOW) phase of the extended Hubbard model (EHM) in one dimension (1D) is characterized at intermediate correlation $U = 4t$ by exact treatment of $N$-site systems. Linear coupling to lattice (Peierls) phonons and molecular (Holstein) vibrations are treated in the adiabatic approximation. The molar magnetic susceptibility $\\chi_M(T)$ is obtained directly up to $N = 10$. The goal is to find the consequences of a doubly degenerate ground state (gs) and finite magnetic gap $E_...

  1. Multicentre randomised double bind crossover trial on contamination of conventional ties and bow ties in routine obstetric and gynaecological practice.

    OpenAIRE

    Biljan, M M; Hart, C. A.; Sunderland, D; Manasse, P R; Kingsland, C R

    1993-01-01

    OBJECTIVE--To assess level of contamination of neckwear worn by gynaecologists and obstetricians during routine working week. DESIGN--Multicentre randomised double blind crossover trial. Participants wore the same conventional ties for three days in one week and bow ties for the same period in second week. SETTING--Two teaching and three district general hospitals in the midlands, Wales, and north England. SUBJECTS--15 registrars and senior registrars. INTERVENTIONS--A swab soaked in sterile ...

  2. Investigation on Ring/Split-Ring Loaded Bow-Tie Antenna for Compactness and Notched-Band

    Science.gov (United States)

    Peng, Lin; Xie, Ji-yang; Jiang, Xing; Li, Si-min

    2016-03-01

    In this paper, a Bow-tie antenna with size reduction, impedance matching and radiation pattern improvement characteristics is designed with an encircling ring. Moreover, further size reduction is achieved by utilizing two symmetric split rings with more frequency tuning flexibility. Research found the ring loaded Bow-tie antenna (RLBA) shows better performance than the referenced Bow-tie antenna (RBA), and the mechanisms of performance improvements are also investigated and found to be the loading ring acts as two symmetric dipoles in the direction of the antenna's polarization. Then, using two symmetric split rings on the opposite side of the substrate as replacement of the encircling ring will prolong the length of the dipoles, and achieves further size reduction. The antenna is denoted as dual split ring loaded Bow-tie antenna (DSRBA). The low cutoff frequencies of RBA, RLBA and DSRBA with identical antenna size are 2.65 GHz, 2.27 GHz and 2.06 GHz, respectively. Then, the corresponding diameters of the antennas are 0.353 λc, 0.303 λc, and 0.275 λc, where λc are their corresponding wavelength of the lower cutoff frequencies. Furthermore, a notched-band is generated as a byproduct of the split rings, and it is owing to the new resonance of the overlap areas of the split rings. The notch can be used to alleviate interference of WiMAX band by carefully choosing the split rings' size. Radiation patterns of RLBA and DSRBA are also improved as current distributions of the high frequencies are trained in order by the ring/split-rings. Measurements are performed to verify the designs.

  3. Quasiparticle self-consistent GW theory of III-V nitride semiconductors: Bands, gap bowing, and effective masses

    DEFF Research Database (Denmark)

    Svane, Axel; Christensen, Niels Egede; Gorczyca, I.;

    2010-01-01

    The electronic band structures of InN, GaN, and a hypothetical ordered InGaN2 compound, all in the wurtzite crystal structure, are calculated using the quasiparticle self-consistent GW approximation. This approach leads to band gaps which are significantly improved compared to gaps calculated....... The band gap of InGaN2 is considerably smaller than what would be expected by linear interpolation implying a significant band gap bowing in InGaN alloys....

  4. YUCCA MOUNTAIN PROJECT - A BRIEFING -

    International Nuclear Information System (INIS)

    This report has the following articles: Nuclear waste--a long-term national problem; Spent nuclear fuel; High-level radioactive waste; Radioactivity and the environment; Current storage methods; Disposal options; U.S. policy on nuclear waste; The focus on Yucca Mountain; The purpose and scope of the Yucca Mountain Project; The approach for permanently disposing of waste; The scientific studies at Yucca Mountain; The proposed design for a repository at Yucca Mountain; Natural and engineered barriers would work together to isolate waste; Meticulous science and technology to protect people and the environment; Licensing a repository; Transporting waste to a permanent repository; The Environmental Impact Statement for a repository; Current status of the Yucca Mountain Project; and Further information available on the Internet

  5. YUCCA MOUNTAIN PROJECT - A BRIEFING --

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2003-08-05

    This report has the following articles: Nuclear waste--a long-term national problem; Spent nuclear fuel; High-level radioactive waste; Radioactivity and the environment; Current storage methods; Disposal options; U.S. policy on nuclear waste; The focus on Yucca Mountain; The purpose and scope of the Yucca Mountain Project; The approach for permanently disposing of waste; The scientific studies at Yucca Mountain; The proposed design for a repository at Yucca Mountain; Natural and engineered barriers would work together to isolate waste; Meticulous science and technology to protect people and the environment; Licensing a repository; Transporting waste to a permanent repository; The Environmental Impact Statement for a repository; Current status of the Yucca Mountain Project; and Further information available on the Internet.

  6. Search for Diffuse X-rays from the Bow Shock Region of Runaway Star BD+43$^\\circ$3654 with Suzaku

    CERN Document Server

    Terada, Yukikatsu; Bamba, Aya; Yamazaki, Ryo; Kouzu, Tomomi; Koyama, Shu; Seta, Hiromi

    2012-01-01

    The bow shocks of runaway stars with strong stellar winds of over 2000 km s$^{-1}$ can serve as particle acceleration sites. The conversion from stellar wind luminosity into particle acceleration power has an efficiency of the same order of magnitude as those in supernova remnants, based on the radio emission from the bow shock region of runaway star BD+43$^\\circ$3654 \\citep{Benaglia10}.If this object exhibits typical characteristics, then runaway star systems can contribute a non-negligible fraction of Galactic cosmic-ray electrons. To constrain the maximum energy of accelerated particles from measurements of possible non-thermal emissions in the X-ray band, Suzaku observed BD+43$^\\circ$3654 in April 2011 with an exposure of 99 ks. Because the onboard instruments have a stable and low background level, Suzaku detected a possible enhancement over the background of $7.6\\pm 3.4$ cnt arcmin$^{-2}$ at the bow shock region, where the error represents the 3 sigma statistics only. However, the excess is not signific...

  7. Numerical simulation of protection range in exploiting the upper protective layer with a bow pseudo-incline technique

    Institute of Scientific and Technical Information of China (English)

    HU Guo-zhong; WANG Hong-tu; LI Xiao-hong; FAN Xiao-gang; YUAN Zhi-gang

    2009-01-01

    The developing processes of stress and deformation fields of a protected layer after mining an upper-protective layer with a bow pseudo-incline technique were simulated to locate the protection region. The pressure relief of the protected layer was analyzed after mining the upper-protective layer. The pressure relief angle along the strike and incline were located according to the rules of protection of the deformation and stress pressure-relief of the protective layer after mining. This results show that the up-per-protective layer with the bow pseudo-incline technique have an upper and downside pressure relief angle of 85 and 68 degrees respectively; the distribution of strike pressure relief angles along the pseudo-incline working face is uneven and their values range from 38.3 to 51 degrees. The pressure relief angle of the inclined middle location was the largest. The distribution of the protection region of the upper-protective layer with the bow pseudo-incline technique located by practical tests and numerical simulation is essentially consistent, compared with the results obtained by these methods.

  8. IR-excesses around nearby Lambda Boo stars are caused by debris disks rather than ISM bow waves

    CERN Document Server

    Draper, Zachary H; Kennedy, Grant M; Wyatt, Mark C; Venn, Kim A; Sibthorpe, Bruce

    2015-01-01

    Lambda Boo stars are predominately A-type stars with solar abundant C, N, O, and S, but up to 2 dex underabundances of refractory elements. The stars' unusual surface abundances could be due to a selective accretion of volatile gas over dust. It has been proposed that there is a correlation between the Lambda Boo phenomenon and IR-excesses which are the result of a debris disk or interstellar medium (ISM) interaction providing the accreting material. We observe 70 or 100 and 160 $\\mu$m excess emission around 9 confirmed Lambda Boo stars with the Herschel Space Observatory, to differentiate whether the dust emission is from a debris disk or an ISM bow wave. We find that 3/9 stars observed host well resolved debris disks. While the remaining 6/9 are not resolved, they are inconsistent with an ISM bow wave based on the dust emission being more compact for its temperature and predicted bow wave models produce hotter emission than what is observed. We find the incidence of bright IR-excesses around Lambda Boo star...

  9. Deceleration of the solar wind upstream from the earth's bow shock and the origin of diffuse upstream ions

    Science.gov (United States)

    Bame, S. J.; Asbridge, J. R.; Feldman, W. C.; Gosling, J. T.; Paschmann, G.; Skopke, N.

    1980-01-01

    Observations with the Los Alamos Scientific Laboratory/Max-Planck-Institut crossed-fan solar wind ion experiment on ISEE I reveal that the solar wind is decelerated and deflected away from the direction of the earth's bow shock as it enters that portion of the upstream region populated by diffuse bow shock ions and long-period (10-60 s) waves. Typically, the average directed velocity vector changes by 7-10 km/s as it enters the wave region. At times, average speed changes as large as 25-40 km/s are observed. Superposed upon these changes in average flow speed are large amplitude (+ or - 15) fluctuations in flow speed associated with the waves themselves. The observations suggest that the solar wind deceleration is the result of momentum transfer from reflected bow shock ions to the wind via the long-period waves as the reflected ion beams go unstable. The broad angular distributions of the diffuse ions thus appear to be produced as a consequence of the disruption of reflected ion beams.

  10. Southeastern Cooperative Wildlife Disease Study, Santee National Wildlife Refuge, 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is an unpublished report by the Southeastern Cooperative Wildlife Disease Study of the Parasitology College of Veterinary Medicine, The University of Georgia....

  11. Southeastern Cooperative Wildlife Disease Study, 1998 and 2004

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Southeastern Cooperative Wildlife Disease Study for white-tailed deer, performed in 1998 and 2004 by the College of Veterinary Medicine of The University of Georgia.

  12. The potential of energy farming in the southeastern California desert

    Science.gov (United States)

    Lew, V.

    1980-04-01

    The use of energy forms to provide future sources of energy for California is considered. Marginal desert lands in southeastern California are proposed for the siting of energy farms using acacia, eucalyptus, euphorbia, guayule, jojoba, mesquite, or tamarisk.

  13. European mountain biodiversity

    Directory of Open Access Journals (Sweden)

    Nagy, Jennifer

    1998-12-01

    Full Text Available This paper, originally prepared as a discussion document for the ESF Exploratory Workshop «Trends in European Mountain Biodiversity - Research Planning Workshop», provides an overview of current mountain biodiversity research in Europe. It discusses (a biogeographical trends, (b the general properties of biodiversity, (c environmental factors and the regulation of biodiversity with respect to ecosystem function, (d the results of research on mountain freshwater ecosystems, and (e climate change and air pollution dominated environmental interactions.- The section on biogeographical trends highlights the importance of altitude and latitude on biodiversity. The implications of the existence of different scales over the different levels of biodiversity and across organism groups are emphasised as an inherent complex property of biodiversity. The discussion on ecosystem function and the regulation of biodiversity covers the role of environmental factors, productivity, perturbation, species migration and dispersal, and species interactions in the maintenance of biodiversity. Regional and long-term temporal patterns are also discussed. A section on the relatively overlooked topic of mountain freshwater ecosystems is presented before the final topic on the implications of recent climate change and air pollution for mountain biodiversity.

    [fr] Ce document a été préparé à l'origine comme une base de discussion pour «ESF Exploratory Workshop» intitulé «Trends in European Mountain Biodiversity - Research Planning Workshop»; il apporte une vue d'ensemble sur les recherches actuelles portant sur la biodiversité des montagnes en Europe. On y discute les (a traits biogéographiques, (b les caractéristiques générales- de la biodiversité, (c les facteurs environnementaux et la régulation de la biodiversité par rapport à la fonction des écosystèmes, (d les résultats des études sur les écosystèmes aquatiques des montagnes et (e les

  14. Petrographic and EMP study of metamorphic rocks from the Variscan basement of Dinarides (Vranica Mountains, Bosnia and Herzegovina)

    International Nuclear Information System (INIS)

    The Vranica Mountains are located in the middle part of Bosnia and Herzegovina or in the southeastern part of the Mid - Bosnian schist Mountains (MBSM). The Mid - Bosnian schist Mountains represent one of the largest allochtonous Paleozoic terranes in the Dinarides. This region is characterized by a multistage geodynamic evolution. The presented results concern Variscan metamorphism of the Silur-Devonian protolith formations that occurred mainly during the Early Carboniferous in LT/MP greenschist facies. Petrographical description of metamorphic rocks is completed by EMPA of muscovite, chlorite and chloritoid. The Early Alpine metamorphic overprint is related to the closure of a Tethyan Basin and Early Cretaceous collision of the Adria microplate with the Tissia-Moesia continental Blocks. The Neo-Alpine metamorphic overprint occurred due to the collision of the African and Euroasian Plates. (authors)

  15. Cherchez la Femme en The Ox-Bow Incident de Wellman: analizando fractales

    Directory of Open Access Journals (Sweden)

    Rose Lema

    2009-01-01

    Full Text Available Se presenta una definición sucinta de conceptos generales provenientes de la Teoría del Caos, empleados particularmente en termodinámica: fractal, autosimilaridad, bifurcación (Mandelbrot y se describe brevemente el principio de Poincaré en torno a la Teoría de los Tres cuerpos. Un método similar con las correspondientes variantes ha sido aplicado por varios estudiosos de las Humanidades, con el fin de demostrar que se puede atravesar un puente entre ideas de éstas y las demás ciencias. Segundo, se aplicó el método para estudiar los personajes femeninos del filme The Ox-Bow Incident de William Wellman, que ganara el Óscar por la mejor película en el mismo año de su producción. Por último, se argumenta que la Geometría Fractal de la Naturaleza conduce a descentralizar el rol de los cowboys que llevan a cabo el linchamiento, mientras que se centra el papel de las mujeres, y, en especial, a visualizar dos personajes femeninos virtuales, gesto que rompe con la aparente linearidad de la trama.

  16. Particle injection and acceleration at earth's bow shock - Comparison of upstream and downstream events

    Science.gov (United States)

    Ellison, Donald C.; Moebius, Eberhard; Paschmann, Goetz

    1990-01-01

    The injection and acceleration of thermal solar wind ions at the quasi-parallel earth's bow shock during radial interplanetary magnetic field conditions is investigated. Active Magnetospheric Particle Tracer Explorers/Ion Release Module satellite observations of complete proton spectra, and of heavy ion spectra above 10 keV/Q, made on September 12, 1984 near the nose of the shock, are presented and compared to the predictions of a Monte Carlo shock simulation which includes diffusive shock acceleration. It is found that the spectral observations are in good agreement with the predictions of the simulation when it is assumed that all accelerated ions originate in the solar wind and are injected into the acceleration mechanism by thermal leakage from the downstream plasma. The efficiency, which is determined directly from the downstream observations, is high, with at least 15 percent of the solar wind energy flux going into accelerated particles. The comparisons allow constraints to be placed on the rigidity dependence of the scattering mean free path and suggest that the upstream solar wind must be slowed substantially by backstreaming accelerated ions prior to undergoing a sharp transition in the viscous subshock.

  17. Prey fish escape by sensing the bow wave of a predator.

    Science.gov (United States)

    Stewart, William J; Nair, Arjun; Jiang, Houshuo; McHenry, Matthew J

    2014-12-15

    Prey fish possess a remarkable ability to sense and evade an attack from a larger fish. Despite the importance of these events to the biology of fishes, it remains unclear how sensory cues stimulate an effective evasive maneuver. Here, we show that larval zebrafish (Danio rerio) evade predators using an escape response that is stimulated by the water flow generated by an approaching predator. Measurements of the high-speed responses of larvae in the dark to a robotic predator suggest that larvae respond to the subtle flows in front of the predator using the lateral line system. This flow, known as the bow wave, was visualized and modeled with computational fluid dynamics. According to the predictions of the model, larvae direct their escape away from the side of their body exposed to more rapid flow. This suggests that prey fish use a flow reflex that enables predator evasion by generating a directed maneuver at high speed. These findings demonstrate a sensory-motor mechanism that underlies a behavior that is crucial to the ecology and evolution of fishes. PMID:25520384

  18. Quantified Energy Dissipation Rates: Electromagnetic Wave Observations in the Terrestrial Bow Shock

    CERN Document Server

    Wilson, L B; Breneman, A W; Contel, O Le; Cully, C; Turner, D L; Angelopoulos, V

    2013-01-01

    We present the first quantified measure of the rate of energy dissipated per unit volume by high frequency electromagnetic waves in the transition region of the Earth's collisionless bow shock using data from the THEMIS spacecraft. Every THEMIS shock crossing examined with available wave burst data showed both low frequency ( 10 Hz) electromagnetic and electrostatic waves throughout the entire transition region and into the magnetosheath. The waves in both frequency ranges had large amplitudes, but the higher frequency waves, which are the focus of this study, showed larger contributions to both the Poynting flux and the energy dissipation rates. The higher frequency waves were identified as combinations of ion-acoustic waves, electron cyclotron drift instability driven waves, electrostatic solitary waves, and whistler mode waves. These waves were found to have: (1) amplitudes capable of exceeding dB ~ 10 nT and dE ~ 300 mV/m, though more typical values were dB ~ 0.1-1.0 nT and dE ~ 10-50 mV/m; (2) energy flu...

  19. Experimental demonstration of bow-shock instability and its numerical analysis

    Science.gov (United States)

    Kikuchi, Y.; Ohnishi, N.; Ohtani, K.

    2016-07-01

    An experimental demonstration was carried out in a ballistic range at high Mach numbers with the low specific heat ratio gas hydrofluorocarbon HFC-134a to observe the unstable bow-shock wave generated in front of supersonic blunt objects. The shadowgraph images obtained from the experiments showed instability characteristics, in which the disturbances grow and flow downstream and the wake flow appears wavy because of the shock oscillation. Moreover, the influence of the body shape and specific heat ratio on the instability was investigated for various experimental conditions. Furthermore, the observed features, such as wave structure and disturbance amplitude, were captured by numerical simulations, and it was demonstrated that computational fluid dynamics could effectively simulate the physical instability. In addition, it was deduced that the shock instability is induced by sound emissions from the edge of the object. This inference supports the dependence of the instability on the specific heat ratio and Mach number because the shock stand-off distance is affected by these parameters and limits the sound wave propagation.

  20. A Novel Design of Circular Edge Bow-Tie Nano Antenna for Energy Harvesting

    Science.gov (United States)

    Haque, Ahasanul; Reza, Ahmed Wasif; Kumar, Narendra

    2015-11-01

    In this study, a novel nano antenna is designed in order to convert the high frequency solar energy, thermal energy or earth re-emitted sun's energy into electricity. The proposed antenna is gold printed on a SiO2 layer, designed as a circular edge bow-tie with a ground plane at the bottom of the substrate. The Lorentz-Drude model is used to analyze the behavior of gold at the infrared band of frequencies. The proposed antenna is designed by 3D-electromagnetic solver, and analyzed for optimization of metal thickness, gap size, and antenna's geometrical length. Simulations are conducted in order to investigate the behavior of the antenna illuminated by the circularly polarized plane wave. The numerical simulations are studied for improving the harvesting E-field of the antenna within 5 THz-40 THz frequency range. The proposed antenna offers multiple resonance frequency and better return loss within the frequency bands of 23.2 THz to 27 THz (bandwidth 3.8 THz) and 31 THz to 35.9 THz (bandwidth 4.9 THz). An output electric field of 0.656 V/µm is simulated at 25.3 THz. The best fitted gap size at the feed point is achieved as 50 nm with the substrate thickness of 1.2 µm.

  1. Development of Flow Forecasting Models in the Bow River at Calgary, Alberta, Canada

    Directory of Open Access Journals (Sweden)

    Victor B. Veiga

    2014-12-01

    Full Text Available River flow forecasting is critical for flood forecasting, reservoir operations, and water resources management. However, flow forecasting can be difficult, challenging and time consuming due to the spatial and temporal variability of climatic conditions and watershed characteristics. From a practical point of view, a simple and intuitive approach might be more preferable than a complex modeling approach. In this study, our objective was to develop short-term (i.e., daily flow forecasting models in the Bow River at the city of Calgary, Alberta, Canada. Here, we evaluated the performance of several regression models, along with a newly proposed “base difference” model, by using antecedent daily river flow values from three gauge stations (i.e., Banff, Seebe, and Calgary. Our analyses revealed that using a multivariable linear regression formulated as a function of upstream gauge stations (i.e., Banff or Seebe and the station of interest (i.e., Calgary using antecedent flows demonstrated strong relationships (i.e., having r2 (coefficient of determination and RMSE (root-mean-square deviation of approximately 0.93 and 14 m3/s, respectively. As such, we opted to suggest that the use of Banff and Calgary stations in forecasting the flows at Calgary could be considered as it would require a relatively lower number of gauge stations.

  2. Computational Fluid Dynamics Based Bulbous Bow Optimization Using a Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    Shahid Mahmood; Debo Huang

    2012-01-01

    Computational fluid dynamics (CFD) plays a major role in predicting the flow behavior of a ship.With the development of fast computers and robust CFD software,CFD has become an important tool for designers and engineers in the ship industry.In this paper,the hull form of a ship was optimized for total resistance using CFD as a calculation tool and a genetic algorithm as an optimization tool.CFD based optimization consists of major steps involving automatic generation of geometry based on design parameters,automatic generation of mesh,automatic analysis of fluid flow to calculate the required objective/cost function,and finally an optimization tool to evaluate the cost for optimization.In this paper,integration of a genetic algorithm program,written in MATLAB,was carried out with the geometry and meshing software GAMBIT and CFD analysis software FLUENT.Different geometries of additive bulbous bow were incorporated in the original hull based on design parameters.These design variables were optimized to achieve a minimum cost function of “total resistance”.Integration of a genetic algorithm with CFD tools proves to be effective for hull form optimization.

  3. Rayleigh Laser Guide Star Systems UnISIS Bow Tie Shutter and CCD39 Wavefront Camera

    CERN Document Server

    Thompson, L A; Crawford, S L; Leach, R W; Thompson, Laird A.; Teare, Scott W.; Crawford, Samuel L.; Leach, Robert W.

    2002-01-01

    Laser guide star systems based on Rayleigh scattering require some means to deal with the flash of low altitude laser light that follows immediately after each laser pulse. These systems also need a fast shutter to isolate the high altitude portion of the focused laser beam to make it appear star-like to the wavefront sensor. We describe how these tasks are accomplished with UnISIS, the Rayleigh laser guided adaptive optics system at the Mt. Wilson Observatory 2.5-m telescope. We use several methods: a 10,000 RPM rotating disk, dichroics, a fast sweep and clear mode of the CCD readout electronics on a 10 $\\mu$s timescale, and a Pockel's cell shutter system. The Pockel's cell shutter would be conventional in design if the laser light were naturally polarized, but the UnISIS 351 nm laser is unpolarized. So we have designed and put into operation a dual Pockel's cell shutter in a unique bow tie arrangement.

  4. Application of Single Spacecraft Methods to Study the Motion of the Venusian Bow Shock

    Science.gov (United States)

    Giagkiozis, Stefanos; Pope, Simon

    2016-07-01

    Collisionless shockwaves are associated with a plethora of processes throughout the universe. Supernova remnant shocks are considered one of the main mechanisms that are capable to accelerate particles at high enough energies as the ones observed in cosmic rays. It is still unknown how these shocks accelerate particle to such high energies. By studying shocks in the heliosphere in order to define as much as possible of their parameter space, we could find the answer to this question. One important collisionless shock parameter is the velocity that the shock is travelling. This velocity can be used to define the spatial scales of the shock. The spatial scale in turn is closely related to the processes that govern the energy dissipation and in turn the nature of the shock. The use of multi-spacecraft measurements are the most reliable method to determine the shock velocity. However single spacecraft measurements are often only available, particularly for planetary missions. In a previous study we examined the accuracy of some of the single spacecraft methods that have been developed. Here we apply these approaches to a series of observations of the Venusian bow shock at different locations using Venus Express magnetic field data.

  5. ANALISA PENGARUH BENTUK LAMBUNG AXE BOW PADA KAPAL HIGH SPEED CRAFT TERHADAP HAMBATAN TOTAL

    Directory of Open Access Journals (Sweden)

    Romadhoni Oni

    2015-06-01

    Full Text Available Hambatan merupakan salah satu faktor utama yang mempengaruhi proses perancangan sebuah kapal. Kapal dengan bentuk lambung yang baik akan menghasilkan hambatan yang efisiensi sehingga operasional kapal dan pergerakan kapal lebih baik. Pada ini penelitian dilakukan dengan memodelkan kapal high speed craft tipe Crew boat panjang 38 meter, lebar 7.6 meter, tinggi 3.65 meter dan draft 1.89 meter. Selanjutnya diselidiki model lambung kapal yang menghasilkan hambatan total paling kecil menggunakan pendekatan studi numerik software (maxsuft hullspeed metode savitsky dan holtrop dan software Computational Fluid Dynamics (CFD. Hasil penelitian berdasarkan analisa numerik (Maxsuft –Hullspeed dan CFD menujukkan pada kecepatan sevice bentuk lambung model AXE Bow memiliki nilai hambatan yang lebih kecil dibandingkan model kapal planing hull chine (HPC dan rounded hull (RH. Hasil perhitungan numerik dan CFD memiliki nilai yang hampir sama pada setiap variasi model. Hasil komparisi yang dilakukan didapatkan selisih total hambatan pada kecepatan 25 knot yaitu  model HPC 1.8 kN, model HPCAB 5.2 kN, model RH 4.8 kN dan model 5.1 kN. Dari perbandingan kedua metode tersebut memiliki selisih cukup kecil yaitu  kurang dari 5%. Selain mendapatkan nilai hambatan Software CFD akan menghasilkan nilai  perbandingan gaya angkat (lift force, dan total pressure yang terdistribusi  pada permukaan model setiap variasi kecepatan.

  6. Hydrology of the Upper Malad River basin, southeastern Idaho

    Science.gov (United States)

    Pluhowski, Edward J.

    1970-01-01

    The report area comprises 485 square miles in the Basin and Range physiographic province. It includes most of eastern' Oneida County and parts of Franklin, Bannock, and Power Counties of southeastern Idaho. Relief is about 5,000 feet; the floor of the Malad Valley is at an average altitude of about 4,400 feet. Agriculture is, by far, ,the principal economic .activity. In 1960 the population of the upper Malad River basin was about 3,600, of which about 60 percent resided in Malad City, the county seat of Oneida County. The climate is semiarid throughout the Malad Valley and its principal tributary valleys; ,above 6,500 feet the climate is subhumid. Annual precipitation ranges from about 13 inches in the lower Malad Valley to more than 30 inches on the highest peaks of the Bannock and Malad ranges. Owing to ,the normally clear atmospheric conditions, large daily and seasonal temperature fluctuations are common. Topography, distance from the Pacific Ocean, .and the general atmospheric circulation are the principal factors governing the climate of the Malad River basin. The westerlies transport moisture from the P.acific Ocean toward southeastern Idaho. The north-south tren4ing mountains flanking the basin are oriented orthogonally to the moisture flux so that they are very effective in removing precipitable water from the air. A minimum uplift of 6,000 feet is required to transport moisture from the Pacific source region; accordingly, most air masses are desiccated long before they reach the Malad basin. Heaviest precipitation is generally associated with steep pressure gradients in the midtroposphere that are so oriented as to cause a deep landward penetration of moisture from the Pacific Ocean. Annual water yields in the project area range from about 0.8 inch in the, lower Malad Valley to more than 19 inches on the high peaks north and east of Malad City. The mean annual water yield for the entire basin is 4 inches, or about 115,000 acre-feet. Evaporation is

  7. Geology at Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-05-01

    Both advocates and critics disagree on the significance and interpretation of critical geological features which bear on the safety and suitability of Yucca Mountain as a site for the construction of a high-level radioactive waste repository. Critics believe that there is sufficient geological evidence to rule the site unsuitable for further investigation. Some advocates claim that there is insufficient data and that investigations are incomplete, while others claim that the site is free of major obstacles. We have expanded our efforts to include both the critical evaluations of existing geological and geochemical data and the collection of field data and samples for the purpose of preparing scientific papers for submittal to journals. Summaries of the critical reviews are presented in this paper.

  8. Variation and Trends of Landscape Dynamics, Land Surface Phenology and Net Primary Production of the Appalachian Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yeqiao; Zhao, Jianjun; Zhou, Yuyu; Zhang, Hongyan

    2012-12-15

    The gradients of the Appalachian Mountains in elevations and latitudes provide a unique regional perspective of landscape variations in the eastern United States and a section of the southeastern Canada. This study reveals patterns and trends of landscape dynamics, land surface phenology and ecosystem production along the Appalachian Mountains using time series data from Global Inventory Modeling and Mapping Studies (GIMMS) and AVHRR Global Production Efficiency Model (GloPEM) datasets. We analyzed the spatial and temporal patterns of Normalized Difference Vegetation Index (NDVI), length of growing season (LOS) and net primary production (NPP) of selected ecoregions along the Appalachian Mountains regions. We compared the results out of the Appalachian Mountains regions in different spatial contexts including the North America and the Appalachian Trail corridor area. To reveal latitudinal variations we analyzed data and compared the results between 30°N-40°N and 40°N-50°N latitudes. The result revealed significant decreases in annual peak NDVI in the Appalachian Mountains regions. The trend for the Appalachian Mountains regions was -0.0018 (R2=0.55, P<0.0001) NDVI unit decrease per year during 25 years between 1982 and 2006. The LOS had prolonged 0.3 day yr-1 during 25 years over the Appalachian Mountains regions. The NPP increased by 2.68 gC m-2yr-2 in Appalachian Mountains regions from 1981 to 2000. The comparison with the North America reveals the effects of topography and ecosystem compositions of the Appalachian Mountains. The comparison with the Appalachian Trail corridor area provides a regional mega-transect view of the measured variables.

  9. The seed plant flora of the Mount Jinggangshan region, southeastern China.

    Directory of Open Access Journals (Sweden)

    Lei Wang

    Full Text Available The Mount Jinggangshan region is located between Jiangxi and Hunan provinces in southeastern China in the central section of the Luoxiao Mountains. A detailed investigation of Mount Jinggangshan region shows that the seed plant flora comprises 2,958 species in 1,003 genera and 210 families (Engler's system adjusted according to Zhengyi Wu's concept. Among them, 23 species of gymnospermae belong to 17 genera and 9 families, and 2,935 species of angiosperms are in 986 genera and 201 families. Moreover, they can also be sorted into woody plants (350 genera and 1,295 species and herbaceous plants (653 genera and 1,663 species. The dominant families are mainly Fagaceae, Lauraceae, Theaceae, Hamamelidaceae, Magnoliaceae, Ericaceae, Styracaceae, Aquifoliaceae, Elaeocarpaceae, Aceraceae, Rosaceae, Corylaceae, Daphniphyllaceae, Symplocaceae, Euphorbiaceae, Pinaceae, Taxodiaceae, Cupressaceae and Taxaceae. Ancient and relic taxa include Ginkgo biloba, Fokieniahodginsii, Amentotaxusargotaenia, Disanthuscercidifolia subsp. longipes, Hamamelismollis, Manglietiafordiana, Magnoliaofficinalis, Tsoongiodendronodorum, Fortuneariasinensis, Cyclocaryapaliurus, Eucommiaulmoides, Sargentodoxacuneata, Bretschneiderasinensis, Camptothecaacuminata, Tapisciasinensis, etc. The flora of Mount Jinggangshan region includes 79 cosmopolitan genera and 924 non-cosmopolitan genera, which are 7.88% and 92.12% of all genera. The latter includes 452 tropical genera (48.92% and 472 temperate genera (51.08%. The temperate elements include 44 genera endemic to China, accounting for 4.76% of all genera. Among 1,003 genera, 465 have only a single species and 401 are oligotypic genera (with 2-5 species. These genera account for 86.34% of all genera. The floristic analysis indicates that the flora of Mount Jinggangshan region is closely related to the flora of Mount Wuyishan region in southeastern China. The flora of Mount Jinggangshan region also contains many elements of central and

  10. Potential high resolution paleoclimate and palaeoecology variations on the southeastern Tibetan Plateau

    Science.gov (United States)

    Wang, Y.; Herzschuh, U.; Liu, X.

    2013-12-01

    Varve analysis is a commonly used method to infer high resolution records from lacustrine sediments, which has been applied to northeastern and southeastern China for crater lakes. However, limited by appropriate archive, it has not yet been widely investigated on the Tibetan Plateau, an area that was recognized with significant influences on climate changes over the Eurasian continent and even the whole globe. Lake Basom Co (approximately 30° N and 94° E) is an alpine mountainous lake situated about 3500 m a.s.l. in the southeastern part of the Tibetan Plateau, covering an area of 26 km2, with maximum water depth of over 120 meters. This area is dominated by the Indian Summer Monsoon, and thus has responded sensitively to the climate change. Furthermore, the lake locates at the transitional zone from alpine forest to the alpine steppe/meadow, which is also an ideal site to infer the past vegetation changes in this region. In summer and autumn 2012, several short cores and two ca. 4-m long sediment cores were recovered under about 80 m water depth. Continuously thin laminations were persevered in both the short cores and the long core fragments. Preliminary analyses on the short cores and Pb/Cs dating results indicate that the upmost 20 cm sediments probably consist of annually formed laminations, i.e. varves. The laminations preserved in the long cores need to be further proved whether they are annually formed. Nevertheless, such record could provide us an opportunity to infer high resolution variations in paleoclimate and palaeoecology histories over this region. Lithology of the upper 14 cm sediment recovered from Lake Basom Co under 60 meters water depth

  11. Ecosystem analysis in the southeastern Bering sea

    Science.gov (United States)

    Walsh, John J.; Peter McRoy, C.

    During a 7-year study of the food-chain dynamics of the outer and middle shelves of the southeastern Bering Sea, numerical models were developed to test ecological hypotheses posed at the event, seasonal, and annual scales of habitat variability. Interannual variations in year class strength of Alaska pollock between warm and cold years are attributed to an order of magnitude decline in prey availability during larval drift in cold years. In cold years delayed increases in seasonal abundance of copepod nauplii, the prey of these larval fish, are attributed to low temperature effects on crustacean metabolism rather than to changes in food availability (phytoplankton). Sinking diatoms, uneaten by the zooplankton in the water column during warm or cold years, are resuspended by wind events and advected seaward every 3 to 5 days during the spring. The ungrazed phytoplankton from the outer shelf are moved offshore and deposited on the adjacent slope. Because of the unusual width of the Bering shelf (˜500km) and a seasonal decline in the number of upwelling, favorable wind events, diatoms of the middle shelf are not exported. They are consumed instead by the benthos, with 10-fold larger infaunal biomass found here than on the outer shelf. An annual carbon budget for the middle shelf suggests consumption of all the primary production in this regime, compared to an apparent export of 48% of the outer shelf primary production to the continental slope.

  12. Seismic risk map for Southeastern Brazil

    International Nuclear Information System (INIS)

    During the last few years, some studies regarding seismic risk were prepared for three regions of Brazil. They were carried on account of two basic interests: first, toward the seismic history and recurrence of Brazilian seismic events; second, in a way as to provide seismic parameters for the design and construction of hydro and nuclear power plants. The first seismic risk map prepared for the southeastern region was elaborated in 1979 by 6he Universidade de Brasilia (UnB-Brasilia Seismological Station). In 1981 another seismic risk map was completed on the basis of seismotectonic studies carried out for the design and construction of the Nuclear power plants of Itaorna Beach (Angra dos Reis, Rio de Janeiro) by IPT (Mining and Applied Geology Division). In Brazil, until 1984, seismic studies concerning hydro and nuclear power plants and other civil construction of larger size did not take into account the seismic events from the point of view of probabilities of seismic recurrences. Such analysis in design is more important than the choice of a level of intensity or magnitude, or adoption of a seismicity level ased on deterministic methods. In this way, some considerations were made, concerning the use of seisms in Brazilian designs of hydro and nuclear power plants, as far as seismic analysis is concerned, recently altered over the current seismic risk panorama. (D.J.M.)

  13. Characterization of contemporary aeolian dust deposition on mountain glaciers of western China

    Institute of Scientific and Technical Information of China (English)

    JianZhong Xu; ShiChang Kang; ShuGui Hou; QiangGong Zhang; Jie Huang; CunDe Xiao; JiaWen Ren; DaHe Qin

    2016-01-01

    From 2008 to 2010, a total of 15 snow pit samples were collected from 13 mountain glaciers in western China. In this study these samples are used to determine the spatial distribution of insoluble particle concentrations and dust deposition fluxes in western China. The results show that the mass concentrations of insoluble particles exhibit high spatial variation and strongly decrease (by a factor of approximately 50) from the north (Tienshan Mountains) to the south (Himalayas). However, the insoluble particles concentrations at the southeastern Tibetan Plateau (TP) sites are also high and ap-proximately 30 times greater than those in the Himalayas. The spatial distribution of the dust flux is similar to that of the mass concentrations; however, the high dust deposition rate in the southeastern TP is very significant as a result of the extensive snow accumulation (precipitation) in this region. The average sizes of the insoluble particles at each site generally exhibit bimodal distributions with peaks at approximately 5 µm and 10 µm, which can be explained as re-sulting from dust emissions from regional and local sources, respectively. The enrichment factors for most of the ele-ments measured in insoluble particles are less than 10 at all of the study sites, indicating primarily crustal sources. However, the sites located in the peripheral mountains of western China, such as the Tienshan Mountains and the Himalayas, are characterized by high levels of certain enrichment elements (e.g., Cu, Zn, Cr, and V) indicative of sources related to the long-range transport of pollutants.

  14. 27 CFR 9.80 - York Mountain.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false York Mountain. 9.80... Mountain. (a) Name. The name of the viticultural area described in this section is “York Mountain.” (b) Approved map. The approved map for the York Mountain viticultural area is the U.S.G.S. map entitled...

  15. 27 CFR 9.55 - Bell Mountain.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bell Mountain. 9.55... Mountain. (a) Name. The name of the viticultural area described in this section is “Bell Mountain.” (b) Approved map. The appropriate map for determining the boundaries of the Bell Mountain viticultural area...

  16. 27 CFR 9.167 - Red Mountain

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Red Mountain 9.167 Section... Mountain (a) Name. The name of the viticultural area described in this section is “Red Mountain.” (b) Approved maps. The appropriate map for determining the boundaries of the Red Mountain viticultural area...

  17. The Dilemma of Mountain Roads

    Science.gov (United States)

    Mountain roads and trails are proliferating throughout developing Southeast Asia with severe but largely unrecognized long-term consequences related to effects of landslides and surface erosion on communities and downstream resources.

  18. The Table Mountain Field Site

    Data.gov (United States)

    Federal Laboratory Consortium — The Table Mountain Field Site, located north of Boulder, Colorado, is designated as an area where the magnitude of strong, external signals is restricted (by State...

  19. H2S in the L1157-B1 bow shock

    Science.gov (United States)

    Holdship, Jonathan; Viti, Serena; Jimenez-Serra, Izaskun; Lefloch, Bertrand; Codella, Claudio; Podio, Linda; Benedettini, Milena; Fontani, Francesco; Bachiller, Rafael; Tafalla, Mario; Ceccarelli, Cecilia

    2016-11-01

    Sulphur-bearing molecules are highly reactive in the gas phase of the interstellar medium. However, the form in which most of the sulphur is locked on to interstellar dust grains is unknown. By taking advantage of the short time-scales of shocks in young molecular outflows, one could track back the main form of sulphur in the ices. In this paper, six transitions of H2S and its isotopologues in the L1157-B1 bow shock have been detected using data from the Herschel-Chemical HErschel Surveys of Star forming regions survey and the IRAM-30m Astrochemical Surveys At IRAM large programme. These detections are used to calculate the properties of H2S gas in L1157-B1 through use of a rotation diagram and to explore the possible carriers of sulphur on the grains. The isotopologue detections allow the first calculation of the H2S deuteration fraction in an outflow from a low-mass protostar. The fractional abundance of H2S in the region is found to be 6.0 × 10-7 and the deuteration fraction is 2 × 10-2. In order to investigate the form of sulphur on the grains, a chemical model is run with four different networks, each with different branching ratios for the freeze out of sulphur-bearing species into molecules such as OCS and H2S. It is found that the model best fits the data when at least half of each sulphur-bearing species hydrogenates when freezing. We therefore conclude that a significant fraction of sulphur in L1157-B1 is likely to be locked in H2S on the grains.

  20. Nonlinear wave-particle interaction upstream from the Earth's bow shock

    Directory of Open Access Journals (Sweden)

    C. Mazelle

    2000-01-01

    Full Text Available Well-defined ring-like backstreaming ion distributions have been recently reported from observations made by the 3DP/PESA-High analyzer onboard the WIND spacecraft in the Earth's foreshock at large distances from the bow shock, which suggests a local production mechanism. The maximum phase space density for these distributions remains localized at a nearly constant pitch-angle value for a large number of gyroperiods while the shape of the distribution remains very steady. These distributions are also observed in association with quasi-monochromatic low frequency (~ 50 mHz waves with substantial amplitude (δB/B>0.2. The analysis of the magnetic field data has shown that the waves are propagating parallel to the background field in the right-hand mode. Parallel ion beams are also often observed in the same region before the observation of both the ring-like distributions and the waves. The waves appear in cyclotron resonance with the ion parallel beams. We investigate first the possibility that the ion beams could provide the free energy source for driving an ion/ion instability responsible for the ULF wave occurrence. For that, we solve the wave dispersion relation with the observed parameters. Second, we show that the ring-like distributions could then be produced by a coherent nonlinear wave-particle interaction. It tends to trap the ions into narrow cells in velocity space centered on a well-defined pitch-angle, directly related to the saturation wave amplitude in the analytical theory. The theoretical predictions are in good quantitative agreement with the observations

  1. Magnetic Field Orientation Effects on the Standoff Distance of Earth's Bow Shock

    Science.gov (United States)

    Cairns, Iver H.; Lyon, J. G.

    1996-01-01

    Three-dimensional, global MHD simulations of solar wind flow onto a prescribed magnetopause obstacle are used to show that a bow shock's nose location a(sub s), and the relative subsolar magnetosheath thickness Delta(sub ms)/a(sub mp) are strong functions of the IMF cone angle theta (between v(sub sw) and B(sub sw)) and the Alfven Mach number M(sub A). For a given M(sub A) the shock is more distant for higher theta (restricted to the interval 0-90deg by symmetries), while a(sub s)/a(sub mp) and Delta(sub ms/a(sub mp) increase with decreasing M(sub A) for theta greater than or approximately 20deg but decrease with decreasing M(sub A) for theta approximately Odeg. Large differences in Delta(sub ms/a(sub mp) are predicted between theta = Odeg and 90deg at low M(sub A), with smaller differences remaining even at M(sub A) approximately 10. The theta = Odeg results confirm and extend the previous work of Spreiter and Rizzi [1974]. The simulations show that successful models for the subsolar shock location cannot subsume the dependences on M(sub A) and theta into a sole dependence on M(ms). Instead, they confirm a recent prediction [Cairns and Grabbe, 1994] that a(sub s)/a(sub mp) and Delta(sub ms)/a(sub mp) should depend strongly on theta and M(sub A) for M(sub A) less than or approximately 10 (as well as on other MHD variables). Detailed comparisons between theory and data remain to be done. However, preliminary comparisons show good agreement, with distant shock locations found for low M(sub A) and large theta greater than or approximately 45deg and closer locations found for theta less than or approximately 20deg even at M/A approximately 8.

  2. Yucca Mountain Project public interactions

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) is committed to keeping the citizens of Nevada informed about activities that relate to the high-level nuclear waste repository program. This paper presents an overview of the Yucca Mountain Project's public interaction philosophy, objectives, activities and experiences during the two years since Congress directed the DOE to conduct site characterization activities only for the Yucca Mountain site

  3. Mesozoic denudation and cooling events of the Yinshan Mountains, southern Mongolian Plateau

    Science.gov (United States)

    Feng, Li-Xia; Han, Bao-Fu; Wang, Zeng-Zhen; Liu, Bo; Brown, Roderick

    2016-04-01

    ABASTRACT The Yinshan Mountains are south boundary of the Mongolian Plateau, occupying the north part of North China Craton. 18 granitoid samples were conducted by apatite fission track method in order to unravel its Mesozoic denudation and cooling history and relationship with the Mongolian Plateau. They obtain Jurassic to Cretaceous AFT ages. 3 main phases of rapid cooling events during Mesozoic are recognized and could probably be caused by denudation. Combined with local geological conditions, denudations are more likely controlled by the local thrust faulting. The Early Jurassic denudation event occurred in the transition area to the Mongolian Plateau. The Late Jurassic to Early Cretaceous denudation events occurred in the interior mountains and are more likely provoked by the distant effect of the Mongol-Okhotsk Orogeny based on their propagation directions. The Late Cretaceous denudation event occurred in the southeastern flank of the mountain. Finally, the activity time of thrust faults are constrained by 130-90 Ma according to the uplift and denudation relationship in the thrust system and their modeling T-t paths. Key words Apatite Fission track; Uplift and denudation; Mesozoic reactivation; Mountain Langshan

  4. Application of the improved Bow-tie risk analysis technology in civil airport safety%基于Bow-Tie技术的民用机场安全风险分析应用研究

    Institute of Scientific and Technical Information of China (English)

    孙殿阁; 孙佳; 王淼; 秦康

    2010-01-01

    民用运输机场具有运行环境复杂、事故成因复杂、驻场单位众多等特点,其事故成因更具有动态性、隐蔽性、综合性和因果连带性.因此,机场的日常运行安全风险分析一般需要借助多种工具才能完成.本文系统的介绍了一种实用的风险分析方法-Bow-tie风险技术,Bow-tie是一种风险分析和风险管理的工具,通过识别和评估风险、分析风险因素、设置风险屏障、采取风险控制和(减缓)恢复措施,有效预防事故发生.该方法可以对危害事件发生的原因、后果、屏障建立是否充足提供一个可视化的评估.本文就Bow-tie技术在民用机场安全风险中的具体实施步骤进行了描述,最后给出了其在民用机场风险分析中应用的一个实例,并就其可行性和实际应用进行了系统的研究.Bow-tie风险技术是集故障树、事件树和圆葱图理论相结合的系统风险分析及量化技术,对组织缺陷以及人为失误占主导因素的民用机场运行安全风险分析,具有较高的应用价值.

  5. 基于 Bow-tie模型的城镇输油管道风险评价方法研究%Study on risk assessment method of urban oil pipeline based on Bow-tie model

    Institute of Scientific and Technical Information of China (English)

    陈玉超; 蒋宏业; 吴瑶晗; 姚安林; 韩晓瑜

    2016-01-01

    According to the leakage and explosion accidents of urban oil pipeline frequently occurred in recent years, it was proposed to introduce Bow-tie model into risk evaluation.Through the combination of Bow-tie model with the improved ana-lytic hierarchy process method, the weights of each influence factor were obtained and sorted.Then the risk evaluation was conducted on pipeline so as to put forward reasonable safety management schemes and reduce the occurrence of accidents. The calculation results showed that the third party factor dominates in the influence factors of pipeline failure, while in the a-nalysis of accident consequence, the safety consequence and environment consequence factors have the largest influence, which basically accord with the actual situation of accident.It has certain guiding significance and practical value for the risk analysis of urban oil pipeline.%根据近年来不断发生的城镇输油管道泄漏爆炸事故,提出将Bow-tie模型引入到风险评价中,将Bow-tie模型和改进的层次分析法相结合得出各影响因素的权重并排序,对管道进行风险评价,便于提出合理的安全管理方案,减少事故的发生。通过计算得到第三方因素在管道失效影响因素中占主导,而在事故后果分析中安全后果和环境后果因素影响较大,基本符合事故实际状况,说明该方法对于城镇输油管道风险分析有一定的指导意义和实用价值。

  6. Bow-Tie分析技术在FPSO建造项目中的应用研究%Application research on Bow-Tie analysis technology in FPSO fabrication project

    Institute of Scientific and Technical Information of China (English)

    杨轶; 孙美芳; 窦林华

    2012-01-01

    @@%系统分析了海洋石油115 FPSO建造项目应用Bow-Tie分析技术,构建“蝴蝶结模型”,对建造施工作业有关的危险因素、控制措施及日常管理工作之间的联系进行研究,对各种顶上事件的起因和后果进行系统分析,此方法用于FPSO建造项目的现场安全管理非常有效.

  7. Bow shock specularly reflected ions in the presence of low-frequency electromagnetic waves: a case study

    Directory of Open Access Journals (Sweden)

    K. Meziane

    2004-07-01

    Full Text Available An energetic ion (E≤40 event observed by the CLUSTER/CIS experiment upstream of the Earth's bow shock is studied in detail. The ion event is observed in association with quasi-monochromatic ULF MHD-like waves, which we show modulate the ion fluxes. According to three statistical bow shock position models, the Cluster spacecrafts are located at ~0.5 Re from the shock and the averaged bow shock θBn0 is about ~30°. The analysis of the three-dimensional angular distribution indicates that ions propagating roughly along the magnetic field direction are observed at the onset of the event. Later on, the angular distribution is gyrophase-bunched and the pitch-angle distribution is peaked at α0Bn0, consistent with the specular reflection production mechanism. The analysis of the waves shows that they are left-handed in the spacecraft frame of reference (right-handed in the solar wind frame and propagate roughly along the ambient magnetic field; we have found that they are in cyclotron-resonance with the field-aligned beam observed just upstream. Using properties of the waves and particles, we explain the observed particle flux-modulation in the context of θBn changes at the shock caused by the convected ULF waves. We have found that the high count rates coincide with particles leaving the shock when θBn angles are less than ~40°, consistent with the specular reflection hypothesis as the production mechanism of ions.

  8. Significance of the 'bow and lean test' for the diagnosis of benign horizontal semicircular canal paroxysmal positional vertigo

    Directory of Open Access Journals (Sweden)

    Ying CHEN

    2012-10-01

    Full Text Available Objective To observe and assess the positive rate and accuracy of 'bow and lean test' in the horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV. Methods Ninety-two HSC-BPPV patients who were diagnosed by head roll test (HRT were enrolled, and then further tested with 'bow and lean test' (BLT between Oct 1, 2010 and Sep 30, 2011. They were treated by Barbecue maneuver or Brandt-Daroff exercise on the basis of HRT and BLT tests. The positive rate of BLT test was analyzed, and its accuracy for diagnosis and success rate for treatment of HSC-BPPV were compared between HRT and BLT. Results Among the 92 patients, 83(90.2% of them showed BLT nystagmus. Fifty-seven of 83 (68.7% patients showed both bowing nystagmus and leaning nystagmus, and 18(21.7% and 8(9.6% respectively showed bowing nystagmus alone or leaning nystagmus alone. Among 92 patients, 74(80.4% of them the affected side could be determined by HRT with 69 BLT positive and 5 BLT negative. Among the 69 BLT-positive patients, 60 patients showed the same result of HRT, and successful result was achieved by manipulation. 9 patients showed different result between BLT and HRT, in whom manipulation failed according to the result of HRT, but succeeded when manipulation was performed according to BLT. In 18 patients(19.6% it was not able to determine the affected side by HRT, but in 14 patients manipulation was successful when BLT result was applied. In 4 patients BLT failed to evoke nystagmus, but after practicing Brandt-Daroff exercise, vertigo and HRT nystagmus disappeared 3 days later. Among the 92 patients, 65(70.7% were cured according to HRT, while 83(90.2% got successful result according to BLT(P < 0.05. Conclusion The positive rate and accuracy for HSC-BPPV by BLT are high. It is a useful method for determining the affected side in HSC-BPPV, and to provide the basis for selecting effective manipulation treatment.

  9. Localized radiative energy transfer from a plasmonic bow-tie nano-antenna to a magnetic thin film stack

    OpenAIRE

    Sendur, K.; Kosar, A.; Mengüç, M. Pınar

    2011-01-01

    Localized radiative energy transfer from a near-field emitter to a magnetic thin film structure is investigated. A magnetic thin film stack is placed in the near-field of the plasmonic nano-antenna to utilize the evanescent mode coupling between the nano-antenna and magnetic thin film stack. A bow-tie nano-optical antenna is excited with a tightly focused beam of light to improve near-field radiative energy transfer from the antenna to the magnetic thin film structure. A tightly focused incid...

  10. Localized radiative energy transfer from a plasmonic bow-tie nanoantenna to a magnetic thin film stack

    OpenAIRE

    Şendur, Kürşat; Sendur, Kursat; Koşar, Ali; Kosar, Ali; Mengüç, Pınar; Menguc, Pinar

    2010-01-01

    Localized radiative energy transfer from a near-field emitter to a magnetic thin film structure is investigated. A magnetic thin film stack is placed in the near-field of the plasmonic nanoantenna to utilize the evanescent mode coupling between the nanoantenna and magnetic thin film stack. A bow-tie nano-optical antenna is excited with a tightly focused beam of light to improve near-field radiative energy transfer from the antenna to the magnetic thin film structure. A tightly focused inci...

  11. Multilayered BOW-TIE Antennas Design for RFID and Radar Applications Using a Simple Equivalent Transmission Line Model

    OpenAIRE

    Didouh, S.; Abri, M.; F. T. Bendimerad

    2012-01-01

    In this paper we propose the design of bow-tie antenna based on a simple modified transmission line model. The developed model is simple, accurate and takes into account all the antenna characteristics.The simulated antennas are designed to resonate at the frequencies 2.4 GHz and 8 GHz corresponding to RFID and Radars applications. To validate this last the obtained simulation results are compared to those obtained by the moment’s method (Agilent Momentum software). Using this transmission li...

  12. Radiometric dating of Precambrian rock in Smaaland southeastern Sweden

    International Nuclear Information System (INIS)

    Dating of zircons with the U-Pb method in southeastern Sweden gives ages of 1837 Ma on volcanics, considered as postorogenic to the Svecokarelian, and 1825 Ma on an arkose (possibly a sheared synorogenic granite). These figures coincide with previous U-Pb ages in southeastern Sweden. Zircons from an older preorogenic gneis and a metasediment do not fit a U-Pb discordia line but imply a previous history back to 2500 Ma ago. Zircons from a dike porphyry intruding the younger volcanics do not yield a meaningful age, probably due to contamination. When compiling the presented U-Pb data with previous Rb-Sr and K-Ar ages the orogenic activity from synorogenic through postorogenic times seems to be continuous in southeastern Sweden. (authors)

  13. Chinese tallow: Invading the southeastern Coastal Plain

    Science.gov (United States)

    ,

    2000-01-01

    Chinese tallow is an ornamental tree with colorful autumn foliage that can survive full sunlight and shade, flooding, drought, and in some cases fire. To horticulturists this kind of tree sounds like a dream, but to ecologists, land managers, and land owners this kind of tree can be a nightmare, especially when it invades an area and takes over native vegetation. Chinese tallow (Triadica sebifera), a nonnative tree from China, is currently transforming the southeastern Coastal Plain.Over the last 30 years, Chinese tallow has become a common tree in old fields and bottomland swamps of coastal Louisiana. Several studies at the U.S. Geological Survey’s National Wetlands Research Center (NWRC), Lafayette, Louisiana, are aimed at understanding the factors that contribute to Chinese tallow growth, spread, and management.When tallow invades, it eventually monopolizes an area, creating a forest without native animal or plant species. This tree exhibits classic traits of most nonnative invaders: it is attractive so people want to distribute it, it has incredible resiliency, it grows quickly and in a variety of soils, and it is resistant to pests.In the coastal prairie of Louisiana and Texas, Chinese tallow can grow up to 30 feet and shade out native sun-loving prairie species. The disappearing of prairie species is troublesome because less than 1% of original coastal prairie remains, and in Louisiana, less than 500 of the original 2.2 million acres still exist.Tallow reproduces and grows quickly and can cause large-scale ecosystem modification (fig. 1). For example, when it completely replaces native vegetation, it has a negative effect on birds by degrading the habitat. Besides shading out grasses that cattle like to eat, it can also be potentially harmful to humans and animals because of its berries (fig. 2) and plant sap that contain toxins. There is some concern its leaves may shed toxins that change the soil chemistry and make it difficult for other plants to grow.

  14. Tectonic history of the southeastern North America

    Energy Technology Data Exchange (ETDEWEB)

    Hatcher, R.D. Jr. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences Oak Ridge National Lab., TN (United States))

    1993-03-01

    The present-day configuration of the crust of southeastern North America (SENA) is the product of a lengthy history traceable through more than 1 billion yr. of geologic time. The Appalachians (AP) record complete Wilson cycles of opening and closing of several oceans from ca. 690 Ma to 245 M. The final event forming the AP was the collision of SENA with Gondwana to form the supercontinent Pangaea. The Ouachitas (OA) had a somewhat different history culminating with island-arc collision during the Pennsylvanian--before the final collision began in the AP. SENA faced the open lapetos ocean no earlier than the Early Cambrian. The AP and OA were built on an earlier margin formed by rifting of the Rodonia super-continent formed by construction of the 1.2 to 1.0 Ga Grenville orogen, and farther west, a crust formed by still earlier (1.3 and 1.8 Ga) events. Recent suggestions that part of the AP platform is in Argentina raises the possibility that a fragment was rifted from between the AP and OA during the early Paleozoic. The crust beneath the Mississippi Embayment is atypical of continental crust, and would have been rifted during the Neoproterozoic and early Paleozoic. The Argentine fragment may have been removed along a transform that was reactivated several times since. Northern Pangaea was rifted during the Late Triassic and Early Jurassic and SENA once again faced open ocean-the nascent present Atlantic (AT) when spreading began. The Gulf of Mexico (GOM) also opened then forming extensive salt deposits. The AT opened partly along the old suture, but produced a failed rift in GA and FL leaving a piece of Africa forming the crust beneath the Coastal Plain as far south as central FL. The overlying sediments record recurrent uplift and decay of the AP and OA, cooling of new AT oceanic crust, eustatic sea-level changes during the Mesozoic and Cenozoic, and uplift of the Rockies providing a new source of voluminous detritus that is still being deposited in the GOM.

  15. Southeastern Regional Environmental Characterization Report: executive summary. Final report

    International Nuclear Information System (INIS)

    This Executive Summary of the final ''Southeastern Regional Environmental Characterization Report'' (RECR) is issued primarily for public information purposes and provides a general overview of the report. The complete RECR presents available regional environmental information pertinent to siting a repository or high-level nuclear waste in crystalline rock in central Maryland; noncoastal Virginia, North Carolina, and South Carolina; and northern Georgia. For each of the states within the Southeastern Region, information is provided on the environmental disqualifying factors and the environmental regional screening variables to be used in region-to-area screening

  16. The foreign investments phenomena in south-eastern European countries

    Directory of Open Access Journals (Sweden)

    Teodora ALECU

    2010-01-01

    Full Text Available The south-eastern Europe countries have all the common history of the communism policy and economy, which from the foreign investments perspective meant a radical approach, which promoted a nationalism view against foreign capital interference. Similar to China, perhaps India and other countries, the governments of the south-eastern Europe’s countries expressed a rejection to foreign investments, emphasizing the negative effects of such operations, arguing that any foreign capital inflow is followed by a foreign capital outflow which at the end will destabilize the balance of external payments and will overall result in no favorable effect upon the economy of their countries.

  17. Southeastern Regional Geologic Characterization Report. Executive summary. Final report

    International Nuclear Information System (INIS)

    This Executive Summary of the final Southeastern Regional Geologic Characterization Report (RGCR) is issued primarily for public information purposes, and provides a general overview of the report. The complete RGCR presents available regional geologic information pertinent to siting a repository for high-level nuclear waste in crystalline rock in central Maryland; noncoastal Virginia, North Carolina, and South Carolina; and northern Georgia. For each of the states within the Southeastern Region, information is provided on the geologic disqualifying factor and the geologic regional screening variables to be used in region-to-area screening

  18. Bat assemblages from three Atlantic Forest fragments in Rio de Janeiro state, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Roberto Leonan Novaes

    2015-01-01

    Full Text Available Bat species richness in Neotropical localities is generally higher than that of any other group of mammals, and surveys of local bat assemblages may provide useful data for conservation management plans. Although the bat fauna of the Rio de Janeiro state is currently one of the best known in Brazil, there are several localities not adequately surveyed yet, and most of them are in the mountainous regions and in the northern portion of the state. From January 2008 to November 2009, we conducted surveys of bats in three localities in the state of Rio de Janeiro (municipalities of Varre-Sai, Sumidouro, and Cantagalo, and our fieldwork constitutes the first assessment of the bat assemblages of these localities. Surveys were conducted using mist nets in four different habitat types in each locality (forest interior, forest edge, riparian forest, and open areas [pastures]. We captured a total of 148 individuals in 17 species, 14 genera and 3 families. Among them, 11 species were recorded in Sumidouro, seven in Cantagalo, and nine in Varre-Sai. Although species richness was low compared with previous surveys in other close localities, we recorded species that have been rarely sampled in Southeastern Brazil (e.g., Macrophyllum macrophyllum [Phyllostomidae]. The results reinforce the importance of sampling different habitats in short surveys to improve the number of species registered.

  19. Landscape Trends in Mid-Atlantic and Southeastern United States Ecoregions

    Science.gov (United States)

    Griffith, J.A.; Stehman, S.V.; Loveland, T.R.

    2003-01-01

    Landscape pattern and composition metrics are potential indicators for broad-scale monitoring of change and for relating change to human and ecological processes. We used a probability sample of 20-km ?? 20-km sampling blocks to characterize landscape composition and pattern in five US ecoregions: the Middle Atlantic Coastal Plain, Southeastern Plains, Northern Piedmont, Piedmont, and Blue Ridge Mountains. Land use/land cover (LULC) data for five dates between 1972 and 2000 were obtained for each sample block. Analyses focused on quantifying trends in selected landscape pattern metrics by ecoregion and comparing trends in land cover proportions and pattern metrics among ecoregions. Repeated measures analysis of the landscape pattern documented a statistically significant trend in all five ecoregions towards a more fine-grained landscape from the early 1970s through 2000. The ecologically important forest cover class also became more fine-grained with time (i.e., more numerous and smaller forest patches). Trends in LULC, forest edge, and forest percent like adjacencies differed among ecoregions. These results suggest that ecoregions provide a geographically coherent way to regionalize the story of national land use and land cover change in the United States. This study provides new information on LULC change in the southeast United States. Previous studies of the region from the 1930s to the 1980s showed a decrease in landscape fragmentation and an increase in percent forest, while this study showed an increase in forest fragmentation and a loss of forest cover.

  20. Holocene tephra stratigraphy in four lakes in southeastern Oregon and northwestern Nevada, USA

    Science.gov (United States)

    Foit, Franklin F.; Mehringer, Peter J.

    2016-03-01

    To better understand the regional tephra stratigraphy and chronology of northern Nevada and southern Oregon, tephras in archived cores, taken as part of the Steens Mountain Prehistory Project from four lakes, Diamond Pond, Fish and Wildhorse lakes in southeastern Oregon and Blue Lake in northwestern Nevada, were reexamined using more advanced electron microprobe analytical technology. The best preserved and most complete core from Fish Lake along with Wildhorse Lake hosted two tephras from Mt. Mazama (Llao Rock and the Climactic Mazama), a mid-Holocene basaltic tephra from Diamond Craters, Oregon, two Medicine Lake tephras and an unexpected late Holocene Chaos Crags (Mt. Lassen volcanic center) tephra which was also found in the other lakes. Blue Lake was the only lake that hosted a Devils Hill tephra from the Three Sisters volcano in west central Oregon. Another tephra from the Three Sisters Volcano previously reported in sediments of Twin Lakes in NE Oregon, has now been confirmed as Rock Mesa tephra. The Chaos Crags, Devils Hill and Rock Mesa tephras are important late Holocene stratigraphic markers for central and eastern Oregon and northwestern Nevada.

  1. Rock glaciers, protalus ramparts and pronival ramparts in the south-eastern Alps

    Science.gov (United States)

    Colucci, R. R.; Boccali, C.; Žebre, M.; Guglielmin, M.

    2016-09-01

    Rock glaciers and protalus ramparts are characteristic landforms of the periglacial domain often used as markers for the occurrence of permafrost in mountain terrains. As such, relict rock glaciers can be used for paleoclimate reconstructions. We present here the first previously unreported rock glacier inventory of the south-eastern Alps (including the north-eastern-most region of Italy and Slovenia), interpreted from high resolution orthophotos and a high resolution digital terrain model interpolated from airborne laser scanning (LiDAR). We mapped 53 rock glaciers covering a total area of 3.45 km2. The majority of rock glaciers are classified as relict and distributed between 1708 and 1846 m a.s.l. with slope ranging between 19° and 27°. In addition to rock glaciers we observed 66 protalus (pronival) ramparts, having median elevation of 1913 m a.s.l. and covering 0.48 km2. More than half of the inventoried protalus ramparts are located in the more maritime area of the Alps with higher precipitation compared to the location of rock glaciers. Using paleoclimate reconstruction based on the 1981-2010 climatological record of the area, we infer that the rock glaciers formed during one of the dry and cold periods of the late Pleistocene and early Holocene. Possible evolution of the active pronival forms observed in the most maritime area of this alpine sector is also discussed.

  2. Conceptual model of recharge to southeastern Badain Jaran Desert groundwater and lakes from environmental tracers

    International Nuclear Information System (INIS)

    Sources of groundwater recharge to the Badain Jaran Desert in China have been investigated using geochemical and isotopic techniques. Stable isotope compositions (δ18O and δ2H) of shallow groundwater and surface water from oasis lakes evolve from a starting composition considerably depleted compared to local unsaturated zone moisture, confirming inferences from chloride mass balance that direct infiltration of precipitation is not a volumetrically important source of recharge to the shallow aquifer in the study area. Shallow phreatic and deeper confined groundwater bodies appear unconnected based on chemical composition and radiocarbon activities. Hydrogeologic evidence points toward a bordering mountain range (Yabulai) as a likely recharge zone, which is consistent with tracer results. A mean residence time in the range of 1-2 ka for the desert's southeastern margin is inferred from radiocarbon. These results reveal that some replenishment to the desert aquifer is occurring but at a rate much lower than previously suggested, which is relevant for water resources planning in this ecologically sensitive area

  3. Ion distribution dynamics near the Earth's bow shock: first measurements with the 2D ion energy spectrometer CORALL on the INTERBALL/Tail-probe satellite

    Directory of Open Access Journals (Sweden)

    Yu. I. Yermolaev

    Full Text Available The dynamics of the ion distribution function near the Earth's bow shock is studied on the basis of quasi-3D measurements of ion energy spectra in the range of 30–24200 eV/q with the Russian-Cuban CORALL instrument on the INTERBALL/Tail-probe satellite. The instrument was designed for observations of magnetospheric plasma and measures ions, in an angular range of 36°–144° from the Earth-Sun direction. Ion populations generated by the Earth bow shock are often observed upstream from the bow shock. In the solar-wind stream compressed and heated by the passing of very dense magnetic cloud (CME, two types of these ion populations were measured upstream and before the bow shock crossing on 25 August 1995 at 07:37 UT. Both populations were observed in the energy range above 2 keV. At ~06:20 UT, when the angle between the direction of the interplanetary magnetic field and normal to the bow shock VBn was ≃ 43° the instrument observed a narrow, fast (~800 km/s field-aligned beam moving from the Earth. At ~07:30, when Bn ≃ 28°, the wide ion pitch-angle distribution was observed. A similar suprathermal ion population is observed in the magnetosheath simultaneously with the solar-wind ion population being heated and deflected from the Sun-Earth direction. The similarity of observations during the mentioned time-interval and under usual solar-wind conditions allows us to conclude that types of suprathermal ion populations upstream and downstream from the bow shock do not depend on the solar-wind disturbance generated by magnetic cloud.

  4. Variation and trends of landscape dynamics, land surface phenology and net primary production of the Appalachian Mountains

    Science.gov (United States)

    Wang, Yeqiao; Zhao, Jianjun; Zhou, Yuyu; Zhang, Hongyan

    2012-01-01

    The gradients of elevations and latitudes in the Appalachian Mountains provide a unique regional perspective on landscape variations in the eastern United States and southeastern Canada. We reveal patterns and trends of landscape dynamics, land surface phenology, and ecosystem production along the Appalachian Mountains using time series data from Global Inventory Modeling and Mapping Studies and Advanced Very High Resolution Radiometer Global Production Efficiency Model datasets. We analyze the spatial and temporal patterns of the normalized difference vegetation index (NDVI), length of growing season (LOS), and net primary production (NPP) of selected ecoregions along the Appalachian Mountains regions. We compare the results in different spatial contexts, including North America and the Appalachian Trail corridor area. To reveal latitudinal variations, we analyze data and compare the results between the 30°-to-40°N and the 40°-to-50°N latitudes. The result reveal significant decreases in annual peak NDVI in the Appalachian Mountains regions. The trend for the Appalachian Mountains regions was a -0.0018 (R2=0.55, Punit decrease per year during 25 years from 1982 to 2006. The LOS was prolonged by 0.3 days per year-1 during the 25-year percent. The NPP increased by 2.68 g Cm-2 yr-2 from 1981 to 2000.

  5. A Precipitation Climatology of the Snowy Mountains, Australia

    Science.gov (United States)

    Theobald, Alison; McGowan, Hamish; Speirs, Johanna

    2014-05-01

    The precipitation that falls in the Snowy Mountains region of southeastern Australia provides critical water resources for hydroelectric power generation. Water storages in this region are also a major source of agricultural irrigation, environmental flows, and offer a degree of flood protection for some of the major river systems in Australia. Despite this importance, there remains a knowledge gap regarding the long-term, historic variability of the synoptic weather systems that deliver precipitation to the region. This research aims to increase the understanding of long-term variations in precipitation-bearing weather systems resulting in runoff into the Snowy Mountains catchments and reservoirs, and the way in which these are influenced by large-scale climate drivers. Here we present initial results on the development of a climatology of precipitation-bearing synoptic weather systems (synoptic typology), spanning a period of over 100 years. The synoptic typology is developed from the numerical weather model re-analysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), in conjunction with regional precipitation and temperature data from a network of private gauges. Given the importance of surface, mid- and upper-air patterns on seasonal precipitation, the synoptic typing will be based on a range of meteorological variables throughout the depth of the troposphere, highlighting the importance of different atmospheric levels on the development and steering of synoptic precipitation bearing systems. The temporal and spatial variability of these synoptic systems, their response to teleconnection forcings and their contribution to inflow generation in the headwater catchments of the Snowy Mountains will be investigated. The resulting climatology will provide new understanding of the drivers of regional-scale precipitation variability at inter- and intra-annual timescales. It will enable greater understanding of how variability in synoptic scale

  6. Estimation of the Effect of Green Water and Bow Flare Slamming on the Wave-Induced Vertical Bending Moment Using Closed-Form Ex-pressions

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Mansour, A. E.

    2003-01-01

    ABSTRACT: The effect of impulsive loads like slamming and green water on deck on the wave-induced bending mo-ment is estimated by a semi-analytical approach. The impulse loads leading to transient vibrations are described in terms of magnitude, phase lag relative to the wave-induced peak and decay...... rate. These loads can be due to bow flare slamming, bottom slamming or green water loads as they all can be characterised by a short duration relative to the wave cycle. The magnitude of the bow flare slamming loads is estimated using accurate results from wedge-shaped sections, Zhao and Faltinsen...

  7. Network, degeneracy and bow tie integrating paradigms and architectures to grasp the complexity of the immune system

    Directory of Open Access Journals (Sweden)

    Tieri Paolo

    2010-08-01

    Full Text Available Abstract Recently, the network paradigm, an application of graph theory to biology, has proven to be a powerful approach to gaining insights into biological complexity, and has catalyzed the advancement of systems biology. In this perspective and focusing on the immune system, we propose here a more comprehensive view to go beyond the concept of network. We start from the concept of degeneracy, one of the most prominent characteristic of biological complexity, defined as the ability of structurally different elements to perform the same function, and we show that degeneracy is highly intertwined with another recently-proposed organizational principle, i.e. 'bow tie architecture'. The simultaneous consideration of concepts such as degeneracy, bow tie architecture and network results in a powerful new interpretative tool that takes into account the constructive role of noise (stochastic fluctuations and is able to grasp the major characteristics of biological complexity, i.e. the capacity to turn an apparently chaotic and highly dynamic set of signals into functional information.

  8. Flux-based classification of reactions reveals a functional bow-tie organization of complex metabolic networks.

    Science.gov (United States)

    Singh, Shalini; Samal, Areejit; Giri, Varun; Krishna, Sandeep; Raghuram, Nandula; Jain, Sanjay

    2013-05-01

    Unraveling the structure of complex biological networks and relating it to their functional role is an important task in systems biology. Here we attempt to characterize the functional organization of the large-scale metabolic networks of three microorganisms. We apply flux balance analysis to study the optimal growth states of these organisms in different environments. By investigating the differential usage of reactions across flux patterns for different environments, we observe a striking bimodal distribution in the activity of reactions. Motivated by this, we propose a simple algorithm to decompose the metabolic network into three subnetworks. It turns out that our reaction classifier, which is blind to the biochemical role of pathways, leads to three functionally relevant subnetworks that correspond to input, output, and intermediate parts of the metabolic network with distinct structural characteristics. Our decomposition method unveils a functional bow-tie organization of metabolic networks that is different from the bow-tie structure determined by graph-theoretic methods that do not incorporate functionality. PMID:23767567

  9. Occurrence of high-beta superthermal plasma events in the close environment of Jupiter's bow shock as observed by Ulysses

    International Nuclear Information System (INIS)

    The ratio of the plasma pressure to the magnetic field pressure (or of their energy densities) which is known as the plasma parameter 'beta'(β) has important implications to the propagation of energetic particles and the interaction of the solar wind with planetary magnetospheres. Although in the scientific literature the contribution of the superthermal particles to the plasma pressure is generally assumed negligible, we deduced, by analyzing energetic particles and magnetic field measurements recorded by the Ulysses spacecraft, that in a series of events, the energy density contained in the superthermal tail of the particle distribution is comparable to or even higher than the energy density of the magnetic field, creating conditions of high-beta plasma. More explicitly, in this paper we analyze Ulysses/HI-SCALE measurements of the energy density ratio (parameter βep) of the energetic ions'(20 keV to ∼5 MeV) to the magnetic field's in order to find occurrences of high-beta (βep>1) superthermal plasma conditions in the environment of the Jovian magnetosphere, which is an interesting plasma laboratory and an important source of emissions in our solar system. In particular, we examine high-beta ion events close to Jupiter's bow shock, which are produced by two processes: (a) bow shock ion acceleration and (b) ion leakage from the magnetosphere.

  10. Large Scale Earth's Bow Shock with Northern IMF as simulated by PIC code in parallel with MHD model

    CERN Document Server

    Baraka, Suleiman M

    2016-01-01

    In this paper, we propose a 3D kinetic model (Particle-in-Cell PIC ) for the description of the large scale Earth's bow shock. The proposed version is stable and does not require huge or extensive computer resources. Because PIC simulations work with scaled plasma and field parameters, we also propose to validate our code by comparing its results with the available MHD simulations under same scaled Solar wind ( SW ) and ( IMF ) conditions. We report new results from the two models. In both codes the Earth's bow shock position is found to be ~14.8 RE along the Sun-Earth line, and ~ 29 RE on the dusk side. Those findings are consistent with past in situ observations. Both simulations reproduce the theoretical jump conditions at the shock. However, the PIC code density and temperature distributions are inflated and slightly shifted sunward when compared to the MHD results. Kinetic electron motions and reflected ions upstream may cause this sunward shift. Species distributions in the foreshock region are depicted...

  11. Timber Mountain Precipitation Monitoring Station

    International Nuclear Information System (INIS)

    A precipitation monitoring station was placed on the west flank of Timber Mountain during the year 2010. It is located in an isolated highland area near the western border of the Nevada National Security Site (NNSS), south of Pahute Mesa. The cost of the equipment, permitting, and installation was provided by the Environmental Monitoring Systems Initiative (EMSI) project. Data collection, analysis, and maintenance of the station during fiscal year 2011 was funded by the U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office Environmental Restoration, Soils Activity. The station is located near the western headwaters of Forty Mile Wash on the Nevada Test and Training Range (NTTR). Overland flows from precipitation events that occur in the Timber Mountain high elevation area cross several of the contaminated Soils project CAU (Corrective Action Unit) sites located in the Forty Mile Wash watershed. Rain-on-snow events in the early winter and spring around Timber Mountain have contributed to several significant flow events in Forty Mile Wash. The data from the new precipitation gauge at Timber Mountain will provide important information for determining runoff response to precipitation events in this area of the NNSS. Timber Mountain is also a groundwater recharge area, and estimation of recharge from precipitation was important for the EMSI project in determining groundwater flowpaths and designing effective groundwater monitoring for Yucca Mountain. Recharge estimation additionally provides benefit to the Underground Test Area Sub-project analysis of groundwater flow direction and velocity from nuclear test areas on Pahute Mesa. Additionally, this site provides data that has been used during wild fire events and provided a singular monitoring location of the extreme precipitation events during December 2010 (see data section for more details). This letter report provides a summary of the site location, equipment, and data collected in

  12. The jumps of physical quantities at fast shocks under pressure anisotropy: theory versus observations at the bow shock

    International Nuclear Information System (INIS)

    The interaction of the solar wind with magnetized planets leads to the formation of the so-called magnetosphere, a cavity generated by the geomagnetic field. The supersonic, superalfvenic, and magnetized solar wind flow interacting with blunt bodies produces a detached bow shock, separating the solar wind from the magnetosheath, the region between the shock wave and the magnetopause. On approach to a planetary obstacle, the solar wind becomes subsonic at the bow shock and then flows past the planet in the magnetosheath. At the bow shock, the plasma parameters and the magnetic field strength change from upstream to downstream, i.e., an increase of plasma density, temperature, pressure, and magnetic field strength, and a decrease of the velocity across the shock. In this PhD thesis we mainly concentrate on the variations of all physical quantities across the bow shock taking into account pressure anisotropy, which is an important feature in space plasma physics and observed by various spacecraft missions in the solar wind as well as in the magnetosheath. Dealing with anisotropic plasma conditions, one has to introduce the so-called pressure tensor, characterized by two scalar pressures, the pressure perpendicular (Pperp) and the pressure parallel (Pparallel) with respect to the magnetic field and in general one speaks of anisotropic conditions for Pperp is not Pparallel. Many spacecraft observations of the solar wind show Pparallel > Pperp, whereas observations of the magnetosheath show the opposite case, Pparallel perp. Therefore, dissipation of kinetic energy into thermal energy plays an important role in studying the variations of the relevant physical quantities across the shock. It has to be mentioned that planetary bow shocks are good examples for fast MHD shock waves. Therefore, the basic equations for describing the changes across the shock can be obtained by integrating the MHD equations in conservative form. We note that these equations, the so

  13. Yearly report, Yucca Mountain project

    Energy Technology Data Exchange (ETDEWEB)

    Brune, J.N.

    1992-09-30

    We proposed to (1) Develop our data logging and analysis equipment and techniques for analyzing seismic data from the Southern Great Basin Seismic Network (SGBSN), (2) Investigate the SGBSN data for evidence of seismicity patterns, depth distribution patterns, and correlations with geologic features (3) Repair and maintain our three broad band downhole digital seismograph stations at Nelson, nevada, Troy Canyon, Nevada, and Deep Springs, California (4) Install, operate, and log data from a super sensitive microearthquake array at Yucca Mountain (5) Analyze data from micro-earthquakes relative to seismic hazard at Yucca Mountain.

  14. Life in the Taihang Mountains

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    THE Taihang Mountain Range meanders for 500 kilometers across the territories of Henan, Shanxi and Hebei provinces. It is an important ecological screen for the North China Plain and source of water. In Hebei’s Shexian County sits Wangjinzhuang, a 300-year-old stone village nestled in the mountains.The village is a stone world-lanes, houses, court-yard walls, towers, pavilions, tables, benches and mills are all hewn fom ancient rock. Streets and lanes are paved in stones of various shapes and sizes whose sur-

  15. WHITE MOUNTAIN WILDERNESS, NEW MEXICO.

    Science.gov (United States)

    Segerstrom, Kenneth; Stotelmeyer, R.B.

    1984-01-01

    On the basis of a mineral survey the White Mountain Wilderness, which constitutes much of the western and northern White Mountains, New Mexico, is appraised to have six areas of probable mineral potential for base and precious metals. If mineral deposits exist in the wilderness, the potential is for small deposits of base and precious metals in veins and breccia pipes or, more significanlty, the possibility for large low-grade disseminated porphyry-type molybdenum deposits. There is little promise for the occurrence of geothermal energy resources in the area.

  16. Late Quaternary vegetation, fire and climate history reconstructed from two cores at Cerro Toledo, Podocarpus National Park, southeastern Ecuadorian Andes

    Science.gov (United States)

    Brunschön, Corinna; Behling, Hermann

    2009-11-01

    The last ca. 20,000 yr of palaeoenvironmental conditions in Podocarpus National Park in the southeastern Ecuadorian Andes have been reconstructed from two pollen records from Cerro Toledo (04°22'28.6"S, 79°06'41.5"W) at 3150 m and 3110 m elevation. Páramo vegetation with high proportions of Plantago rigida characterised the last glacial maximum (LGM), reflecting cold and wet conditions. The upper forest line was at markedly lower elevations than present. After ca. 16,200 cal yr BP, páramo vegetation decreased slightly while mountain rainforest developed, suggesting rising temperatures. The trend of increasing temperatures and mountain rainforest expansion continued until ca. 8500 cal yr BP, while highest temperatures probably occurred from 9300 to 8500 cal yr BP. From ca. 8500 cal yr BP, páramo vegetation re-expanded with dominance of Poaceae, suggesting a change to cooler conditions. During the late Holocene after ca. 1800 cal yr BP, a decrease in páramo indicates a change to warmer conditions. Anthropogenic impact near the study site is indicated for times after 2300 cal yr BP. The regional environmental history indicates that through time the eastern Andean Cordillera in South Ecuador was influenced by eastern Amazonian climates rather than western Pacific climates.

  17. Altitude, Acute Mountain Sickness and Headache

    Science.gov (United States)

    ... Follow us on Instagram DONATE TODAY Altitude, Acute Mountain Sickness and Headache Abuse, Maltreatment, and PTSD and Their Relationship to Migraine Altitude, Acute Mountain Sickness and Headache Alcohol and Migraine Anxiety and ...

  18. Rocky Mountain Spotted Fever: Statistics and Epidemiology

    Science.gov (United States)

    ... The CDC Cancel Submit Search The CDC Rocky Mountain Spotted Fever (RMSF) Note: Javascript is disabled or ... please visit this page: About CDC.gov . Rocky Mountain Spotted Fever (RMSF) Symptoms, Diagnosis, and Treatment Statistics ...

  19. Some Spatial Aspects of Southeastern United States Climatology.

    Science.gov (United States)

    Soule, Peter T.

    1998-01-01

    Focuses on the climatology of an eight-state region in the southern and southeastern United States. Discusses general controls of climate and spatial patterns of various climatic averages. Examines mapped extremes as a means of fostering increased awareness of the variability that exists for climatic conditions in the region. (CMK)

  20. Rabies in the insectivorous bat Tadarida brasiliensis in Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Uieda Wilson

    1998-01-01

    Full Text Available This is the first recorded case of rabies in the insectivorous bat Tadarida brasiliensis in the State of S. Paulo, Southeastern Brazil. The infected bat was found in the afternoon while hanging on the internal wall of an urban building. This observation reinforces the notion as to the caution one must exercise regarding bats found in unusual situations.

  1. Social Compact in Electricity Privatization in Southeastern Turkey

    OpenAIRE

    Darendeliler, Zeynep; Aydin, Cansu

    2015-01-01

    About 70 percent of electricity users in Southeastern Turkey are not used to paying for electricity, partially due to the protracted situation of conflict and lack of trust between citizens and the government in the region. Historic tension throughout the 1990s caused an inability for the government to invest in electricity infrastructure and has resulted in low service quality. A large po...

  2. Economics of conservation systems research in the Southeastern United States

    Science.gov (United States)

    The use of conservation systems in crop production is not a new concept in the southeastern United States. In 1978, researchers from across the Southeast met in Griffin, Georgia for the first annual Southern Conservation Agricultural Systems Conference. Four of the ten presentations specifically men...

  3. Effects of organophosphorus insecticides on sage grouse in southeastern Idaho

    Science.gov (United States)

    Blus, L.J.; Staley, C.S.; Henny, C.J.; Pendleton, G.W.; Craig, T.H.; Craig, E.H.; Halford, D.K.

    1989-01-01

    Unverified reports indicated die-offs of sage grouse have occurred since the 1970s in southeastern Idaho. Some verification that organophosphorus insecticides were involved was obtained in 1981 and 1983. A radio telemetry study indicated that dimethoate was responsible for most mortality. Methamidophos also acounted for mortality. Sage grouse populations may be adversely affected by organophosphorus insecticides.

  4. 27 CFR 9.102 - Sonoma Mountain.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Sonoma Mountain. 9.102... Sonoma Mountain. (a) Name. The name of the viticultural area described in this section is “Sonoma Mountain.” (b) Approved maps. The approved maps for determining the boundary of the Sonoma...

  5. 49 CFR 71.8 - Mountain zone.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  6. 27 CFR 9.94 - Howell Mountain.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Howell Mountain. 9.94... Howell Mountain. (a) Name. The name of the viticultural area described in this section is “Howell Mountain.” (b) Approved maps. The appropriate maps for determining the boundaries of the Howell...

  7. Anatomy of a Mountain Range.

    Science.gov (United States)

    Chew, Berkeley

    1993-01-01

    Provides written tour of Colorado Rockies along San Juan Skyway in which the geological features and formation of the mountain range is explored. Discusses evidence of geologic forces and products such as plate tectonic movement and the Ancestral Rockies; subduction and the Laramide Orogeny; volcanism and calderas; erosion, faulting, land…

  8. A mountain of millipedes I

    DEFF Research Database (Denmark)

    Enghoff, Henrik

    2014-01-01

    Twenty new species of the millipede genus Chaleponcus Attems, 1914, are described from the Udzungwa Mountains: C. netus sp. nov., C. quasimodo sp. nov., C. malleolus sp. nov., C. scopus sp. nov., C. nikolajscharffi sp. nov., C. mwanihanensis sp. nov., C. basiliscus sp. nov., C. krai sp. nov., C...

  9. 基于Bow-Tie模型的航空事故分析及适航条款生成方法%Analysing Aviation Accident and Generating Airworthiness Provisions using Bow-Tie Model

    Institute of Scientific and Technical Information of China (English)

    崔利杰; 任恒; 李泽

    2015-01-01

    随着航空器需求量的不断增加,人们对航空器安全性水平提出了更高的要求.适航法规作为保证航空器安全性水平的重要依据,其主要来源于航空飞行事故.通过运用Bow-Tie方法模型对民用航空事故进行深入细致分析,找出事故危险源以及相关影响因素,基于分析结果,运用风险管理的理念,提出一种适航条款生成的思路.

  10. 屏蔽罩高度对bow-tie天线性能影响的分析%Numerical and Experimental Analysis of Bow-tie Antennas With Changing of Shield's Height

    Institute of Scientific and Technical Information of China (English)

    周凯; 张文吉; 张晓娟

    2008-01-01

    本文研究了一种终端加载的bow-tie天线,计算所加载的电阻值,并改变其屏蔽罩高度,对其辐射特性和驻波比(VSWR),用软件进行了仿真分析,同时进行了实际测试,并将仿真和实验结果进行了对比.结果表明,仿真和实验的结果基本吻合,为今后进一步的研究工作打下了一定的基础.

  11. AE AURIGAE: FIRST DETECTION OF NON-THERMAL X-RAY EMISSION FROM A BOW SHOCK PRODUCED BY A RUNAWAY STAR

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Santiago, J.; Pereira, V.; De Castro, E. [Dpto. de Astrofisica y CC. de la Atmosfera, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Miceli, M.; Bonito, R. [Dipartimento di Fisica, Universita di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy); Del Valle, M. V.; Romero, G. E. [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina); Albacete-Colombo, J. F. [Centro Universitario Regional Zona Atlantica (CURZA), Universidad Nacional del COMAHUE, Monsenor Esandi y Ayacucho, 8500 Viedma, Rio Negro (Argentina); Damiani, F. [INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy)

    2012-09-20

    Runaway stars produce shocks when passing through interstellar medium at supersonic velocities. Bow shocks have been detected in the mid-infrared for several high-mass runaway stars and in radio waves for one star. Theoretical models predict the production of high-energy photons by non-thermal radiative processes in a number sufficiently large to be detected in X-rays. To date, no stellar bow shock has been detected at such energies. We present the first detection of X-ray emission from a bow shock produced by a runaway star. The star is AE Aur, which was likely expelled from its birthplace due to the encounter of two massive binary systems and now is passing through the dense nebula IC 405. The X-ray emission from the bow shock is detected at 30'' northeast of the star, coinciding with an enhancement in the density of the nebula. From the analysis of the observed X-ray spectrum of the source and our theoretical emission model, we confirm that the X-ray emission is produced mainly by inverse Compton upscattering of infrared photons from dust in the shock front.

  12. Laser resonators with several mirrors and lenses with the bow-tie laser resonator with compensation for astigmatism and thermal lens enects as an example

    DEFF Research Database (Denmark)

    Abitan, Haim; Skettrup, Torben

    2005-01-01

    Laser resonators with several mirrors (lenses) have been investigated in a systematic fashion. They have been grouped into classes according to their number n of mirrors/lenses. Stability polynomials, beam waist radii and locations have been obtained for each group up to n = 4. The bow-tie laser...

  13. Mountain potentials in aid of tourism

    Directory of Open Access Journals (Sweden)

    Stanković Stevan M.

    2002-01-01

    Full Text Available Mountains are distinguished by specific characteristics according to a series of elements, occurrences, processes, shapes, significance for human society and influence on the hydrosphere, atmosphere, and biosphere. In the world as well as in this country, many mountain tourist regions have become affirmed, with developed winter, summer and whole year tourism. They have important recreational, health, sport-manifestation and cultural-manifestation significance. The best economic effects based on the development of mountain tourism are accomplished where mountains are appropriately evaluated. This must be truly expressed in the year 2002, which has been named the year for protection of mountains.

  14. Climate variability in the Carpathian Mountains Region over 1961-2010

    Science.gov (United States)

    Cheval, Sorin; Birsan, Marius-Victor; Dumitrescu, Alexandru

    2014-07-01

    The Carpathian Mountains Region (CMR) lies over parts of the territories of seven Central and Southeastern European countries, and the mountain chain induces major changes in the temperate climate specific to the latitudes between 43° and 49°N. Different administrations govern the long-term meteorological networks; the infrastructure, collection protocols, and storage capacities are specific to each country, so that a comprehensive study on the climate of the area has met considerable difficulties along time. Climate of the Carpathian Region (CARPATCLIM) is a regional initiative developed between 2010 and 2013 aiming to enhance the climatic information in the area by providing comprehensive, temporally and spatially homogenous data sets of the main meteorological variables. Based on daily data aggregated to a monthly scale at 10-km resolution, this study exploits and promotes the results of the CARPATCLIM project, documenting the variability of the main climatic variables over 1961-2010. For each month, the significant increasing or decreasing trends were identified, mapped and placed in the context of previous studies and climate change perspectives. The study has revealed several patterns in the climatic variability, i.e., positive or negative trends prevailing over the entire area, very distinct delineation between various trends induced by the Carpathian Mountain chain, and pledges for further scientific approaches, i.e., causes of the variability and applications in other domains.

  15. Submarine-fan sedimentation, Ouachita Mountains, Arkansas and Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Moiola, R.J.; Shanmugam, G.

    1984-09-01

    More than 10,000 m (32,808 ft) of interbedded sandstones and shales comprise the Upper Mississippian and Lower Pennsylvanian flysch succession (Stanley, Jackfork, Johns Valley, Atoka) in the Ouachita Mountains of Arkansas and Oklahoma. Deposited primarily by turbidity current and hemipelagic processes in bathyal and abyssal water depths, these strata formed major submarine-fan complexes that prograded in a westward direction along the axis of an elongate remnant ocean basin that was associated with the collision and suturing of the North American and African-South American plates. A longitudinal fan system is visualized as the depositional framework for these strata, which were deposited in a setting analogous to the modern Bengal fan of the Indian Ocean. Facies analysis of the Jackfork formation indicates that inner fan deposits are present in the vicinity of Little Rock, Arkansas; middle fan channel and interchannel deposits occur at DeGray Dam and Friendship, Arkansas; and outer fan depositional-lobe deposits are present in southeastern Oklahoma. Boulder-bearing units (olistostromes), many with exotic clasts, were shed laterally into the Ouachita basin. They occur throughout the flysch succession and in all fan environments (i.e., inner, middle, and outer). This relationship may serve as a useful criterion for recognizing analogous longitudinal fan systems in the rock record.

  16. 斧艏船加附体改善耐波性的研究%Research on Sea Keeping Performance of an AXE Bow Ship with Appendages

    Institute of Scientific and Technical Information of China (English)

    施军; 曾青; 武庆威; 高霄鹏; 董祖舜

    2015-01-01

    斧艏船型是一种适用于高速排水船的性能优良船型。无论与高速圆舭型船还是常规深 V 型船相比,它在阻力和耐波性能上均有其优势。研究发现,斧艏船在阻力及耐波性方面仍有进一步改善的余地。为此作者对斧艏船进行了加附体的试验研究。通过加防溅条、尾分水踵、尾压浪板、球鼻艏及首部水翼等手段,使斧艏船的阻力和耐波性有了进一步的改善。研究表明,对于不同的航速范围,可以采用不同的附体组合,以达到较理想的效果。%The hull form with AXE bow has good performance for high speed displacement ships. Both performances of resistance and sea keeping are superior to the round bilge or deep-V hull. A series of model tests of a hull with AXE bow, with various appendages added including spray strip, transom plate, skeg, bow-bulb, bow-bulb with fin and hydrofoil, has been carried out. It is indicated that the appendages can improve the performance of the ship with AXE bow, and different composition of appendages should be adopted for various speed ranges.

  17. Acceleration of solar wind ions to 1 MeV by electromagnetic structures upstream of the Earth's bow shock

    CERN Document Server

    Stasiewicz, K; Eliasson, B; Strumik, M; Yamauchi, M

    2013-01-01

    We present measurements from the ESA/NASA Cluster mission that show in situ acceleration of ions to energies of 1 MeV outside the bow shock. The observed heating can be associated with the presence of electromagnetic structures with strong spatial gradients of the electric field that lead to ion gyro-phase breaking and to the onset of chaos in ion trajectories. It results in rapid, stochastic acceleration of ions in the direction perpendicular to the ambient magnetic field. The electric potential of the structures can be compared to a field of moguls on a ski slope, capable of accelerating and ejecting the fast running skiers out of piste. This mechanism may represent the universal mechanism for perpendicular acceleration and heating of ions in the magnetosphere, the solar corona and in astrophysical plasmas. This is also a basic mechanism that can limit steepening of nonlinear electromagnetic structures at shocks and foreshocks in collisionless plasmas.

  18. Feasibility evaluation of x-ray imaging for measurement of fuel rod bowing in CFTL test bundles

    International Nuclear Information System (INIS)

    The Core Flow Test Loop (CFTL) is a high temperature, high pressure, out-of-reactor helium-circulating system. It is designed for detailed study of the thermomechanical performance, at prototypic steady-state and transient operating conditions, of electrically heated rods that simulate segments of core assemblies in the Gas-Cooled Fast Breeder reactor demonstration plant. Results are presented of a feasibility evaluation of x-ray imaging for making measurements of the displacement (bowing) of fuel rods in CFTL test bundles containing electrically heated rods. A mock-up of a representative CFTL test section consisting of a test bundle and associated piping was fabricated to assist in this evaluation

  19. H2O masers in a jet-driven bow shock: episodic ejection from a massive young stellar object

    Science.gov (United States)

    Burns, R. A.; Handa, T.; Nagayama, T.; Sunada, K.; Omodaka, T.

    2016-07-01

    We report the results of VERA (VLBI Exploration of Radio Astrometry) multi-epoch VLBI (very long baseline interferometry) 22 GHz water maser observations of S255IR-SMA1, a massive young stellar object located in the S255 star-forming region. By annual parallax the source distance was measured as D = 1.78^{+0.12}_{-0.11} kpc and the source systemic motion was (μαcos δ, μδ) = (-0.13 ± 0.20, -0.06 ± 0.27) mas yr-1. Masers appear to trace a U-shaped bow shock whose morphology and proper motions are well reproduced by a jet-driven outflow model with a jet radius of about 6 au. The maser data, in the context of other works in the literature, reveal ejections from S255IR-SMA1 to be episodic, operating on time-scales of ˜1000 yr.

  20. Multilayered BOW-TIE Antennas Design for RFID and Radar Applications Using a Simple Equivalent Transmission Line Model

    Directory of Open Access Journals (Sweden)

    S. Didouh

    2012-06-01

    Full Text Available In this paper we propose the design of bow-tie antenna based on a simple modified transmission line model. The developed model is simple, accurate and takes into account all the antenna characteristics.The simulated antennas are designed to resonate at the frequencies 2.4 GHz and 8 GHz corresponding to RFID and Radars applications. To validate this last the obtained simulation results are compared to those obtained by the moment’s method (Agilent Momentum software. Using this transmission line approach the resonant frequency, input impedance, return loss can be determined simultaneously. The paper reports several simulation results that confirm the validity of the developed model. The obtained results are then presented and discussed.