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Sample records for bow ridge fault

  1. 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)

    Taylor, E.M.; Huckins, H.E.

    1995-01-01

    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

  2. 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)

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

    1997-01-01

    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

  3. Dynamical instability produces transform faults at mid-ocean ridges.

    Science.gov (United States)

    Gerya, Taras

    2010-08-27

    Transform faults at mid-ocean ridges--one of the most striking, yet enigmatic features of terrestrial plate tectonics--are considered to be the inherited product of preexisting fault structures. Ridge offsets along these faults therefore should remain constant with time. Here, numerical models suggest that transform faults are actively developing and result from dynamical instability of constructive plate boundaries, irrespective of previous structure. Boundary instability from asymmetric plate growth can spontaneously start in alternate directions along successive ridge sections; the resultant curved ridges become transform faults within a few million years. Fracture-related rheological weakening stabilizes ridge-parallel detachment faults. Offsets along the transform faults change continuously with time by asymmetric plate growth and discontinuously by ridge jumps.

  4. Exploring tectonomagmatic controls on mid-ocean ridge faulting and morphology with 3-D numerical models

    Science.gov (United States)

    Howell, S. M.; Ito, G.; Behn, M. D.; Olive, J. A. L.; Kaus, B.; Popov, A.; Mittelstaedt, E. L.; Morrow, T. A.

    2016-12-01

    Previous two-dimensional (2-D) modeling studies of abyssal-hill scale fault generation and evolution at mid-ocean ridges have predicted that M, the ratio of magmatic to total extension, strongly influences the total slip, spacing, and rotation of large faults, as well as the morphology of the ridge axis. Scaling relations derived from these 2-D models broadly explain the globally observed decrease in abyssal hill spacing with increasing ridge spreading rate, as well as the formation of large-offset faults close to the ends of slow-spreading ridge segments. However, these scaling relations do not explain some higher resolution observations of segment-scale variability in fault spacing along the Chile Ridge and the Mid-Atlantic Ridge, where fault spacing shows no obvious correlation with M. This discrepancy between observations and 2-D model predictions illuminates the need for three-dimensional (3-D) numerical models that incorporate the effects of along-axis variations in lithospheric structure and magmatic accretion. To this end, we use the geodynamic modeling software LaMEM to simulate 3-D tectono-magmatic interactions in a visco-elasto-plastic lithosphere under extension. We model a single ridge segment subjected to an along-axis gradient in the rate of magma injection, which is simulated by imposing a mass source in a plane of model finite volumes beneath the ridge axis. Outputs of interest include characteristic fault offset, spacing, and along-axis gradients in seafloor morphology. We also examine the effects of along-axis variations in lithospheric thickness and off-axis thickening rate. The main objectives of this study are to quantify the relative importance of the amount of magmatic extension and the local lithospheric structure at a given along-axis location, versus the importance of along-axis communication of lithospheric stresses on the 3-D fault evolution and morphology of intermediate-spreading-rate ridges.

  5. Magnetic anomalies across the southern Central Indian Ridge: evidence for a new transform fault

    Digital Repository Service at National Institute of Oceanography (India)

    Chaubey, A.K.; Krishna, K.S.; SubbaRaju, L.V.; Rao, D.G.

    , Vol. 37. No. 4. pp. MT-~a56, 1990. 0198-.0149/90 $3.(gl + 0.00 Pnnled in Great Britain. (~ 1990 Pergartma Ptes6 pie Magnetic anomalies across the southern Central Indian Ridge: evidence for a new transform fault A. K. CHAUBEY,* K. S. KRISHNA,* L. V... to the ridge are identified as sea-floor spreading lineations 2.2A,3.3A and 4. A half spreading rate of 2.2 cm y- t is estimated for the last I0 Ma. The ridge jump between the anomalies 2-2A (approx. 2.5 Ma) and a new left lateral transform fault offsetting...

  6. Faults and ridges - Historical development in Tempe Terra and Ulysses Patera regions of Mars

    International Nuclear Information System (INIS)

    Scott, D.H.; Dohm, J.M.

    1990-01-01

    Tempe Terra and the area north of Ulysses Patera are selected to demonstrate the various stages of faulting and ridge development in local areas. This work is accomplished by using Viking photomosaics to determine crosscutting relations of structures as well as their morphology and trend orientations. Results show that from the Early Noachian through the Early Amazonian Epochs, at least eight episodes of faulting occurred at Tempe Terra and six at Ulysses Patera. Tectonic activity at Tempe Terra was expressed mainly by densely spaced faults along the northeast extension of the Tharsis rise; faulting culminated in the Middle and Late Noachian and was superseded by transverse fault systems from the Alba Patera region during the Hesperian. Ridge formation, however, was most active in the Early Hesperian. At Ulysses Patera, an early history of tectonism is recorded by complex arrays of faults in a relatively small area of Noachian rocks. 14 refs

  7. Large fault fabric of the Ninetyeast Ridge implies near-spreading ridge formation

    Digital Repository Service at National Institute of Oceanography (India)

    Sager, W.W.; Paul, C.F.; Krishna, K.S.; Pringle, M.S.; Eisin, A.E.; Frey, F.A.; Rao, D.G.; Levchenko, O.V.

    of the high ridge. At 26°S, prominent NE-SW 97 oriented lineations extend southwest from the ridge. Some appear to connect with N-S fracture 98 zone troughs east of NER, implying that the NE-SW features are fracture zone scars formed after 99 the change... to the 105 ridge (Fig. 3). This is especially true for NER south of ~4°S. Where KNOX06RR crossed a 106 gravity lineation, negative gradient features correspond to troughs whereas positive gradient 107 features result from igneous basement highs (Fig. 3...

  8. Direct evidence of hydration into mantle during shearing below a trasform fault: Prince Edward transform fault, Southwest Indian Ridge

    Science.gov (United States)

    Michibayashi, K.; Kakihata, Y.; Dick, H. J.

    2017-12-01

    Southwest Indian Ridge (SWIR) is located to the southwest of Rodriguez Triple Junction, where three Indian ocean ridges meet (Zhou & Dick, 2013, Nature). SWIR is one of the slowest spreading ocean ridges in the world. In this study, we studied microstructural development of 21 peridotite samples obtained from Prince Edward transform fault of SWIR by PROTEA5 cruise in 1983. The peridotites consist dominantly of olivine, orthopyroxene and clinopyroxene with minor amounts of amphibole and plagioclase as well as secondary minerals such as serpentine and magnetite. The peridotites were classified into four groups based on their microstructures: 3 ultramylonites mostly consisting of extremely fine crystals (3-5µm), 13 heterogeneous tectonites consisting of coarse-grained crystals and fine-grained matrix, 1 cataclasite and 4 intensely serpentinized peridotites. Olivine Mg# is 0.90-0.91 and spinel Cr# is 0.1-0.35. Amphibole crystals have chemical compositions of tremolite and magnesio-hornblende and they were intensely deformed within the ultramylonites and the heterogeneous tectonites, indicating that they have occurred before or during intense shearing in mantle. Moreover, extremely fine grain sizes of olivine and microboudin textures in both pyroxene and spinel crystals suggest that these peridotites have been sheared under high stress conditions. Furthermore, olivine crystal-fabrics within the amphibole bearing peridotites have B and E types that could be developed under hydrous conditions, whereas olivine fabrics within the other peridotites have A and D types that could be developed under anhydrous conditions (Karato et al., 2008, Annu. Rev. Earth Planet. Sci.). Consequently, the petrophysical characteristics of peridotites in this study indicate that the uppermost mantle below the Prince Edward transform fault has been locally but intensely hydrated during shearing due to transform movement.

  9. Slip on Ridge Transform Faults: Insights From Earthquakes and Laboratory Experiments

    Science.gov (United States)

    2005-06-01

    the volume of continental crust [Turcotte, release reported by the CMT catalog for each RTF. The1986; Aviles et al., 1987; King et al., 1988; Hirata...faults, Teconophyslcs, 118, 313-327. 30(12), 1618, doi:10.1029/2002GL016454. King , G. C. P., R. S. Stein, and J. B. Rundle (1988), The growth of Fnrncis...with temperatures of T < 600’C. Mylonites collected from the Shaka fracture zone on the South West Indian Ridge provide additional evidence for

  10. Bowed Strings

    Science.gov (United States)

    Rossing, Thomas D.; Hanson, Roger J.

    In the next eight chapters, we consider some aspects of the science of bowed string instruments, old and new. In this chapter, we present a brief discussion of bowed strings, a subject that will be developed much more thoroughly in Chap. 16. Chapters 13-15 discuss the violin, the cello, and the double bass. Chapter 17 discusses viols and other historic string instruments, and Chap. 18 discusses the Hutchins-Schelleng violin octet.

  11. Multi-type Tectonic Responses to Plate Motion Changes of Mega-Offset Transform Faults at the Pacific-Antarctic Ridge

    Science.gov (United States)

    Zhang, F.; Lin, J.; Yang, H.; Zhou, Z.

    2017-12-01

    Magmatic and tectonic responses of a mid-ocean ridge system to plate motion changes can provide important constraints on the mechanisms of ridge-transform interaction and lithospheric properties. Here we present new analysis of multi-type responses of the mega-offset transform faults at the Pacific-Antarctic Ridge (PAR) system to plate motion changes in the last 12 Ma. Detailed analysis of the Heezen, Tharp, and Udintsev transform faults showed that the extensional stresses induced by plate motion changes could have been released through a combination of magmatic and tectonic processes: (1) For a number of ridge segments with abundant magma supply, plate motion changes might have caused the lateral transport of magma along the ridge axis and into the abutting transform valley, forming curved "hook" ridges at the ridge-transform intersection. (2) Plate motion changes might also have caused vertical deformation on steeply-dipping transtensional faults that were developed along the Heezen, Tharp, and Udintsev transform faults. (3) Distinct zones of intensive tectonic deformation, resembling belts of "rift zones", were found to be sub-parallel to the investigated transform faults. These rift-like deformation zones were hypothesized to have developed when the stresses required to drive the vertical deformation on the steeply-dipping transtensional faults along the transform faults becomes excessive, and thus deformation on off-transform "rift zones" became favored. (4) However, to explain the observed large offsets on the steeply-dipping transtensional faults, the transform faults must be relatively weak with low apparent friction coefficient comparing to the adjacent lithospheric plates.

  12. Depth-varying seismogenesis on an oceanic detachment fault at 13°20‧N on the Mid-Atlantic Ridge

    Science.gov (United States)

    Craig, Timothy J.; Parnell-Turner, Ross

    2017-12-01

    Extension at slow- and intermediate-spreading mid-ocean ridges is commonly accommodated through slip on long-lived faults called oceanic detachments. These curved, convex-upward faults consist of a steeply-dipping section thought to be rooted in the lower crust or upper mantle which rotates to progressively shallower dip-angles at shallower depths. The commonly-observed result is a domed, sub-horizontal oceanic core complex at the seabed. Although it is accepted that detachment faults can accumulate kilometre-scale offsets over millions of years, the mechanism of slip, and their capacity to sustain the shear stresses necessary to produce large earthquakes, remains subject to debate. Here we present a comprehensive seismological study of an active oceanic detachment fault system on the Mid-Atlantic Ridge near 13°20‧N, combining the results from a local ocean-bottom seismograph deployment with waveform inversion of a series of larger teleseismically-observed earthquakes. The unique coincidence of these two datasets provides a comprehensive definition of rupture on the fault, from the uppermost mantle to the seabed. Our results demonstrate that although slip on the deep, steeply-dipping portion of detachment faults is accommodated by failure in numerous microearthquakes, the shallow, gently-dipping section of the fault within the upper few kilometres is relatively strong, and is capable of producing large-magnitude earthquakes. This result brings into question the current paradigm that the shallow sections of oceanic detachment faults are dominated by low-friction mineralogies and therefore slip aseismically, but is consistent with observations from continental detachment faults. Slip on the shallow portion of active detachment faults at relatively low angles may therefore account for many more large-magnitude earthquakes at mid-ocean ridges than previously thought, and suggests that the lithospheric strength at slow-spreading mid-ocean ridges may be concentrated

  13. Using bathymetry and reflective seismic profiles to tests a suspected link between melt flux and cumulative fault heave at mid-ocean ridges

    Science.gov (United States)

    Haughton, G.; Murton, B. J.; Le Bas, T.; Henstock, T.

    2017-12-01

    The interplay between magma supply and spreading rate is believed to play a major role in determining large scale seafloor morphology. Here we use bathymetry to test this relationship in areas with similar spreading rates and differing magma supplies. By using open source bathymetry data we have developed a repeatable, automated method for categorising seafloor cumulative fault heave and then attempt to identify the controlling variables. We measure the total apparent fault heave along axis and off-axis at 29°N and 60°N on the Mid-Atlantic Ridge then compare this to proxies for deformation and magma supply. Two approaches are adopted for identifying faults: one using bathymetry and the other spreading-parallel seismic reflection data. The first re-examines the orthogonally spreading Broken Spur segment (26°N) spreading at 23 mm yr-1 (full rate). The other examines the Reykjanes Ridge (60°N) spreading obliquely at 21 mm yr-1 (full rate), which may be influenced by the Icelandic hotspot. Each have contrasting residual depth and structure, with the former being typical of slow spreading ridges, with marked axial valleys, whereas the latter is more typical of fast spreading ridge morphology, with smooth axial rise. We find that high total heave (indicating high tectonic spreading) on the Broken Spur segment does not correlate with high mantle Bouguer anomalies (indicating thin crust and low melt flux). From this we hypothesise that total heave on the large scale at the Broken Spur segment is not controlled by crustal thickness or melt supply. At the Raykjanes Ridge, V-shaped ridges have thicker crust (measured seismically) which converge south of Iceland. These are thought to reflect transient (every 4-6 Myrs) pulses of hot mantle radiating away from the Iceland plume. We find ridge-symmetrical variation in fault heave but with a lower frequency (6-8 Myrs) and longer wavelength (3-7 Myrs) than the V-shaped ridges. Our analysis shows that plume pulses do not

  14. Magmatic controls on axial relief and faulting at mid-ocean ridges

    Science.gov (United States)

    Liu, Zhonglan; Buck, W. Roger

    2018-06-01

    Previous models do not simultaneously reproduce the observed range of axial relief and fault patterns at plate spreading centers. We suggest that this failure is due to the approximation that magmatic dikes open continuously rather than in discrete events. During short - lived events, dikes open not only in the strong axial lithosphere but also some distance into the underlying weaker asthenosphere. Axial valley relief affects the partitioning of magma between the lithosphere and asthenosphere during diking events. The deeper the valley, the more magma goes into lithospheric dikes in each event and so the greater the average opening rate of those dikes. The long-term rate of lithospheric dike opening controls faulting rate and axial depth. The feedback between axial valley depth D and lithospheric dike opening rate allows us to analytically relate steady-state values of D to lithospheric thickness HL and crustal thickness HC. A two-dimensional model numerical model with a fixed axial lithospheric structure illustrates the analytic model implications for axial faulting. The predictions of this new model are broadly consistent with global and segment-scale trends of axial depth and fault patterns with HL and HC.

  15. Off-fault ground ruptures in the Santa Cruz Mountains, California: Ridge-top spreading versus tectonic extension during the 1989 Loma Prieta earthquake

    Science.gov (United States)

    Ponti, Daniel J.; Wells, Ray E.

    1991-01-01

    The Ms 7.1 Loma Prieta earthquake of 18 October 1989 produced abundant ground ruptures in an 8 by 4 km area along Summit Road and Skyland Ridge in the Santa Cruz Mountains. Predominantly extensional fissures formed a left-stepping, crudely en echelon pattern along ridges of the hanging-wall block southwest of the San Andreas fault, about 12 km northwest of the epicenter. The fissures are subparallel to the San Andreas fault and appear to be controlled by bedding planes, faults, joints, and other weak zones in the underlying Tertiary sedimentary strata of the hanging-wall block. The pattern of extensional fissures is generally consistent with tectonic extension across the crest of the uplifted hanging-wall block. Also, many displacements in Laurel Creek canyon and along the San Andreas and Sargent faults are consistent with right-lateral reverse faulting inferred for the mainshock. Additional small tensile failures along the axis of the Laurel anticline may reflect growth of the fold during deep-seated compression. However, the larger ridge-top fissures commonly have displacements that are parallel to the north-northeast regional slope directions and appear inconsistent with east-northeast extension expected from this earthquake. Measured cumulative displacements across the ridge crests are at least 35 times larger than that predicted by the geodetically determined surface deformation. These fissures also occur in association with ubiquitous landslide complexes that were reactivated by the earthquake to produce the largest concentration of co-seismic slope failures in the epicentral region. The anomalously large displacements and the apparent slope control of the geometry and displacement of many co-seismic surface ruptures lead us to conclude that gravity is an important driving force in the formation of the ridge-top fissures. Shaking-induced gravitational spreading of ridges and downslope movement may account for 90¿ or more of the observed displacements on

  16. Segmentation along the Queen Charlotte Fault: The long-lived influence of plate-motion rotation and Explorer Ridge fracture zones

    Science.gov (United States)

    Miller, N. C.; Walton, M. A. L.; Brothers, D. S.; Haeussler, P. J.; Ten Brink, U. S.; Conrad, J. E.; Kluesner, J.; Andrews, B. D.

    2017-12-01

    The Queen Charlotte Fault (QCF) generally tracks the flow line for Pacific/North America (Pa/NA) relative motion since 20 Ma, indicating that the plate boundary localized along an optimally oriented small circle geometry. Rotation in Pa/NA motion at 10—12 Ma caused the QCF south of 53 N to be oblique to plate motion by 10—20. This oblique convergence appears to be accommodated in part by underthrusting of the Pacific Plate beneath Haida Gwaii and in part by slip on faults west of the QCF. On the west side of the QCF, a series of ridges and small basins oriented subparallel to either the QCF or relative plate motion form a 40-km-wide terrace. New high-resolution seismic reflection data image the seaward edge of the ridges as a vertical contact between horizontal or sometimes downwarped deep-sea sediments and west-vergent anticlinal structures within the ridges, supporting earlier interpretations that these ridges have accommodated some component of oblique motion. We argue that the ridges originated as step overs from fracture zones on Explorer Ridge, analogous to the current fault geometry at the southernmost end of the QCF. There, the Revere-Dellwood Fracture Zone (RDFZ) overlaps the QCF for 120 km and connects to the QCF via a more-optimally oriented extensional right step. 3.9—6.4 Mw strike-slip earthquakes along the RDFZ and a lack of contractional seafloor morphologies along the QCF south of the RDFZ-QCF right step suggest that the step over and reactivation along the RDFZ accommodates a majority of plate motion in this region. Kinematic reconstruction of ridges from 54—56 N indicates that they also originated in a similar location, potentially as right steps from either the RDFZ or Sovanco Fracture Zone. Similarly, the RDFZ flow path is coincident with a truncation of seafloor magnetic anomalies and the outer edge of the ridge-bounded terrace, which both parallel the QCF since at least the onset of Explorer Ridge spreading at 8 Ma. The RDFZ-QCF right

  17. Bulbous Bow Shape Optimization

    OpenAIRE

    Blanchard , Louis; Berrini , Elisa; Duvigneau , Régis; Roux , Yann; Mourrain , Bernard; Jean , Eric

    2013-01-01

    International audience; The aim of this study is to prove the usefulness of a bulbous bow for a fishing vessel, in terms of drag reduction, using an automated shape optimization procedure including hydrodynamic simulations. A bulbous bow is an appendage that is known to reduce the drag, thanks to its influence on the bow wave system. However, the definition of the geometrical parameters of the bulb, such as its length and thickness, is not intuitive, as both parameters are coupled with regard...

  18. Preliminary U-series disequilibrium and thermoluminescence ages of surficial deposits and paleosols associated with Quaternary fault, Eastern Yucca Mountain

    International Nuclear Information System (INIS)

    Paces, J.B.; Menges, C.M.; Bush, C.A.; Futa, K.; Millard, H.T.; Maat, P.B.; Whitney, J.W.; Widmann, B.; Wesling, J.R.

    1994-01-01

    Geochronological control is an essential component of paleoseismic evaluation of faults in the Yucca Mountain region. New U-series disequilibrium and thermoluminescence age estimates for pedogenic deposits that bracket surface-rupture events are presented from four sites exposing the Paintbrush Canyon, Bow Ridge and Stagecoach Road faults. Ages show an internal consistency with stratigraphic relationships as well as an overall concordancy between the two independent geochronometers. Age estimates are therefore interpreted to date depositional events or episodes of pedogenic carbonate mobility that can be used to establish a paleoseismic fault chronology. Ultimately, this type of chronological information will be used to evaluate seismic hazards at Yucca Mountain

  19. Complex Tectono-Magmatic Interaction along the George V Transform Fault, South-East Indian Ridge, 140°E, and Implications for Mantle Dynamics

    Science.gov (United States)

    Briais, A.; Ruellan, E.; Ceuleneer, G.; Maia, M.

    2017-12-01

    The 300 km-offset George V Transform Fault (TF) is the westernmost of the major, right-stepping transform faults that offset the South-East Indian Ridge between 140°E and 155°E. All these TFs have multiple shear zones with intra-transform ridge segments (ITRS), mostly unmapped yet. We present the results of the analysis of geophysical and petrological data collected during the STORM cruise (South Tasmania Ocean Ridge and Mantle). The data cover the western shear zone and part of two ITRSs. They reveal a complex interaction between tectonic processes at the plate boundary and near-axis volcanic activity along and across the transform fault. The western TF shear zone consists of two segments offset by a 50 km-long, 15 km-wide, up to 2000 m-high serpentinite massif. We infer that the massif is a push-up resulting from transpression along the transform, due to the lengthening of the western ITRS, with a mechanism similar to the processes currently uplifting the mylonitic massif along the St. Paul TF in the Equatorial Atlantic (1). The western ITRS is relatively shallow and magmatically robust, which is unexpected in a TF system. The bathymetric and backscatter maps also reveal a series of recent off-axis oblique volcanic ridges. Rocks dredged on one of these ridges consist of picrites (i.e. basalts rich in olivine phenocrysts). These observations suggest that the TF there is not magma starved like many mid-ocean ridge transforms, but is the locus of significant primitive melt supply. Such an unexpected production of high-Mg melt might be related to the presence of a mantle thermal anomaly beneath the easternmost SEIR, and/or to a western flow of mantle across the TF. *STORM cruise scientific party: A. Briais, F. Barrere, C. Boulart, D. Brunelli, G. Ceuleneer, N. Ferreira, B. Hanan, C. Hémond, S. Macleod, M. Maia, A. Maillard, S. Merkuryev, S.H. Park, S. Révillon, E. Ruellan, A. Schohn, S. Watson, and Y.S. Yang. (1) Maia et al. 2016 Nature Geo. doi:10.1038/ngeo2759

  20. Geochemistry, mineralization, structure, and permeability of a normal-fault zone, Casino mine, Alligator Ridge district, north central Nevada

    Science.gov (United States)

    Hammond, K. Jill; Evans, James P.

    2003-05-01

    We examine the geochemical signature and structure of the Keno fault zone to test its impact on the flow of ore-mineralizing fluids, and use the mined exposures to evaluate structures and processes associated with normal fault development. The fault is a moderately dipping normal-fault zone in siltstone and silty limestone with 55-100 m of dip-slip displacement in north-central Nevada. Across-strike exposures up to 180 m long, 65 m of down-dip exposure and 350 m of along-strike exposure allow us to determine how faults, fractures, and fluids interact within mixed-lithology carbonate-dominated sedimentary rocks. The fault changes character along strike from a single clay-rich slip plane 10-20 mm thick at the northern exposure to numerous hydrocarbon-bearing, calcite-filled, nearly vertical slip planes in a zone 15 m wide at the southern exposure. The hanging wall and footwall are intensely fractured but fracture densities do not vary markedly with distance from the fault. Fault slip varies from pure dip-slip to nearly pure strike-slip, which suggests that either slip orientations may vary on faults in single slip events, or stress variations over the history of the fault caused slip vector variations. Whole-rock major, minor, and trace element analyses indicate that Au, Sb, and As are in general associated with the fault zone, suggesting that Au- and silica-bearing fluids migrated along the fault to replace carbonate in the footwall and adjacent hanging wall rocks. Subsequent fault slip was associated with barite and calcite and hydrocarbon-bearing fluids deposited at the southern end of the fault. No correlation exists at the meter or tens of meter scale between mineralization patterns and fracture density. We suggest that the fault was a combined conduit-barrier system in which the fault provides a critical connection between the fluid sources and fractures that formed before and during faulting. During the waning stages of deposit formation, the fault behaved as

  1. Medicine Bow wind project

    Science.gov (United States)

    Nelson, L. L.

    1982-05-01

    The Bureau of Reclamation (Bureau) conducted studies for a wind turbine field of 100 MW at a site near Medicine Bow, WY, one of the windiest areas in the United States. The wind turbine system would be electrically interconnected to the existing Federal power grid through the substation at Medicine Bow. Power output from the wind turbines would thus be integrated with the existing hydroelectric system, which serves as the energy storage system. An analysis based on 'willingness to pay' was developed. Based on information from the Department of Energy's Western Area Power Administration (Western), it was assumed that 90 mills per kWh would represent the 'willingness to pay' for onpeak power, and 45 mills per kWh for offpeak power. The report concludes that a 100-MW wind field at Medicine Bow has economic and financial feasibility. The Bureau's construction of the Medicine Bow wind field could demonstrate to the industry the feasibility of wind energy.

  2. InRidge program: Preliminary results from the first cruise

    Digital Repository Service at National Institute of Oceanography (India)

    Mukhopadhyay, R.; Murthy, K.S.R.; Iyer, S.D.; Rao, M.M.M.; Banerjee, R.; Subrahmanyam, A.S.; Shirodkar, P.V.; Ghose, I.

    The first cruise under India's own Ridge research initiative, InRidge collected new data on bathymetry, free-air gravity and magnetic anomalies across the ridge axis between the Vema and Zhivago transform faults in the Central Indian Ridge...

  3. Seafloor Tectonic Fault Fabric and the Evolution of the Walvis Ridge-Rio Grande Rise Hot Spot Twins in the South Atlantic

    Science.gov (United States)

    Sager, W. W.; Engfer, D.; Thoram, S.; Koppers, A. A. P.; Class, C.

    2015-12-01

    Walvis Ridge (WR) and Rio Grande Rise (RGR) are Cretaceous-Cenozoic large igneous provinces (LIPs) formed by the Tristan-Gough hot spot interacting with the Mid-Atlantic Ridge (MAR). Although hot spot-ridge interaction has long been considered a primary factor controlling WR-RGR morphology, details are fuzzy owing to sparse geophysical data. We examined tectonic fabric revealed in satellite altimetry-derived gravity data to infer details about RGR-WR evolution. Plate tectonic reconstructions indicate that the main RGR plateau and large N-S plateau in the eastern WR erupted at the same point at ~90 Ma. Over the next ~8 Myr, these conjunct LIPs formed a "V" shape with a basin in between. Curved fracture zones within the basin imply the two LIPs formed around a microplate. The prominent rift in the middle of RGR formed nearly perpendicular to the RGR-WR intersection, suggesting an extensional microplate boundary. Hot spot eruptions continued at the MAR, emplacing the eastern WR and two main RGR plateaus until ~60 Ma. During this period, the N-S trending Eastern Rio Grande Rise (ERGR) was erupted along the MAR. Both the ERGR and WR formed bathymetric lineaments parallel to seafloor fault fabric and were likely connected. This resulted in WR seamounts with a "tadpole" shape, the head being small to medium seamounts on the WR track and the tails being low, spreading-fabric-parallel ridges extending up to ~150 km northward. Similar, small seamounts are found in the contemporaneous ERGR. Another critical observation is that the WR-RGR formed at a large crustal discontinuity (~700 km at anomaly C33, ~84 Ma) at one or more fracture zone offsets. By late Cenozoic time (anomaly C5, ~10 Ma), the offset was reduced by half while several new fracture zones formed at the junction between RGR and WR. This implies a connection between ridge reorganization and RGR-WR volcanism that may have resulted from the fracture zones becoming oblique to the spreading direction as Euler poles

  4. Fuel pin bowing in CAGR

    International Nuclear Information System (INIS)

    Crossland, I.G.

    1982-01-01

    Some of the more important mechanisms by which pin bowing can occur in Advanced Gas Cooled Reactors are examined. These include creep relaxation of the stresses which occur when thermal bowing is restrained and asymmetric axial clad creep. The clad temperature changes which accompany such bowing are also investigated and the theoretical results briefly compared with the empirical behaviour. (author)

  5. Active faulting on the Ninetyeast Ridge and its relation to deformation of the Indo-Australian plate

    Digital Repository Service at National Institute of Oceanography (India)

    Sager, W.W.; Bull, J.M.; Krishna, K.S.

    Southampton, University of Southampton, Southampton SO14 3ZH, UK , bull@noc.soton.ac.uk 4CSIR - National Institute of Oceanography, Dona Paula, Goa 403004, India, krishna@nio.org Abstract The ~4500 km-long Ninetyeast Ridge (NER) in the northeastern...

  6. Cenozoic tectono-thermal history of the Tordrillo Mountains, Alaska: Paleocene-Eocene ridge subduction, decreasing relief, and late Neogene faulting

    Science.gov (United States)

    Benowitz, Jeff A.; Haeussler, Peter J.; Layer, Paul W.; O'Sullivan, Paul B.; Wallace, Wes K.; Gillis, Robert J.

    2012-01-01

    Topographic development inboard of the continental margin is a predicted response to ridge subduction. New thermochronology results from the western Alaska Range document ridge subduction related orogenesis. K-feldspar thermochronology (KFAT) of bedrock samples from the Tordrillo Mountains in the western Alaska Range complement existing U-Pb, 40Ar/39Ar and AFT (apatite fission track) data to provide constraints on Paleocene pluton emplacement, and cooling as well as Late Eocene to Miocene vertical movements and exhumation along fault-bounded blocks. Based on the KFAT analysis we infer rapid exhumation-related cooling during the Eocene in the Tordrillo Mountains. Our KFAT cooling ages are coeval with deposition of clastic sediments in the Cook Inlet, Matanuska Valley and Tanana basins, which reflect high-energy depositional environments. The Tordrillo Mountains KFAT cooling ages are also the same as cooling ages in the Iliamna Lake region, the Kichatna Mountains of the western Alaska Range, and Mt. Logan in the Wrangell-St. Elias Mountains, thus rapid cooling at this time encompasses a broad region inboard of, and parallel to, the continental margin extending for several hundred kilometers. We infer these cooling events and deposition of clastic rocks are related to thermal effects that track the eastward passage of a slab window in Paleocene-Eocene time related to the subduction of the proposed Resurrection-Kula spreading ridge. In addition, we conclude that the reconstructed KFATmax negative age-elevation relationship is likely related to a long period of decreasing relief in the Tordrillo Mountains.

  7. Atelier Bow-Wow DELIGHTS

    DEFF Research Database (Denmark)

    Kajita, Masashi

    2011-01-01

    Atelier Bow-Wow bruger det engelske ord 'delights' til at beskrive en arkitektonisk kvalitet, der dækker over fornøjelse, nydelse og glæde. Interviewet med Yoshiharu Tskukamoto, der sammen med Momoyo Kaijima leder Atelier Bow-Wow, udforsker baggrunden for begrebet 'delights', hvordan det spiller...

  8. Analysis of PWR assembly bow

    International Nuclear Information System (INIS)

    Fetterman, Robert J.; Franceschini, Fausto

    2008-01-01

    Excessive out of core assembly bow has been observed during refueling outages of certain PWRs. Assembly bow can take on a rather complex S-shape, and in other cases C-shape bow is prevalent. Concerns have been raised regarding the impact of the observed assembly bow on the in-core power distribution and the safety analyses supporting the plant operations. In response to these concerns, Westinghouse has developed a comprehensive analysis process for determining the effects of assembly bow on core power distributions and plant operating margins. This methodology has been applied to a particular reactor as part of an overall safety reanalysis completed in support of plant modifications. This paper provides a brief description of the methods used and a summary of the pertinent results. (authors)

  9. Analysis of PWR assembly bow

    Energy Technology Data Exchange (ETDEWEB)

    Fetterman, Robert J.; Franceschini, Fausto [Westinghouse Electric Company LLC, Pittsburgh, PA (United States)

    2008-07-01

    Excessive out of core assembly bow has been observed during refueling outages of certain PWRs. Assembly bow can take on a rather complex S-shape, and in other cases C-shape bow is prevalent. Concerns have been raised regarding the impact of the observed assembly bow on the in-core power distribution and the safety analyses supporting the plant operations. In response to these concerns, Westinghouse has developed a comprehensive analysis process for determining the effects of assembly bow on core power distributions and plant operating margins. This methodology has been applied to a particular reactor as part of an overall safety reanalysis completed in support of plant modifications. This paper provides a brief description of the methods used and a summary of the pertinent results. (authors)

  10. Bow shock data analysis

    Science.gov (United States)

    Zipf, Edward C.; Erdman, Peeter W.

    1994-08-01

    The University of Pittsburgh Space Physics Group in collaboration with the Army Research Office (ARO) modeling team has completed a systematic organization of the shock and plume spectral data and the electron temperature and density measurements obtained during the BowShock I and II rocket flights which have been submitted to the AEDC Data Center, has verified the presence of CO Cameron band emission during the Antares engine burn and for an extended period of time in the post-burn plume, and have adapted 3-D radiation entrapment codes developed by the University of Pittsburgh to study aurora and other atmospheric phenomena that involve significant spatial effects to investigate the vacuum ultraviolet (VUV) and extreme ultraviolet (EUV) envelope surrounding the re-entry that create an extensive plasma cloud by photoionization.

  11. Preliminary results of paleoseismic investigations of Quaternary faults on eastern Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Menges, C.M.; Oswald, J.A.; Coe, J.A.

    1995-01-01

    Site characterization of the potential nuclear waste repository at Yucca Mountain, Nevada, requires detailed knowledge of the displacement histories of nearby Quaternary faults. Ongoing paleoseismic studies provide data on the amount and rates of Quaternary activity on the Paintbrush Canyon, Bow Ridge, and Stagecoach Road faults along the eastern margin of the mountain over varying time spans of 0-700 ka to perhaps 0-30 ka, depending on the site. Preliminary stratigraphic interpretations of deposits and deformation at many logged trenches and natural exposures indicate that each of these faults have experienced from 3 to 8 surface-rupturing earthquakes associated with variable dip-slip displacements per event ranging from 5 to 115 cm, and commonly in the range of 20 to 85 cm. Cumulative dip-slip offsets of units with broadly assigned ages of 100-200 ka are typically less than 200 cm, although accounting for the effects of possible left normal-oblique slip could increase these displacements by factors of 1.1 to 1.7. Current age constraints indicate recurrence intervals of 10 4 to 10 5 years (commonly between 30 and 80 k.y.) and slip rates of 0.001 to 0.08 mm/yr (typically 0.01-0.02 mm/yr). Based on available timing data, the ages of the most recent ruptures varies among the faults; they appear younger on the Stagecoach Road Fault (∼5-20 ka) relative to the southern Paintbrush Canyon and Bow Ridge faults (∼30-100 ka)

  12. The player and the bowed string: coordination of bowing parameters in violin and viola performance.

    Science.gov (United States)

    Schoonderwaldt, E

    2009-11-01

    An experiment was conducted with four violin and viola players, measuring their bowing performance using an optical motion capture system and sensors on the bow. The measurements allowed for a detailed analysis of the use and coordination of the main bowing parameters bow velocity, bow force, and bow-bridge distance. An analysis of bowing strategies in detache playing of notes of three durations (0.2, 2, and 4 s) at three dynamic levels (pp, mf, and f) on all four strings is presented, focusing on the "steady" part of the notes. The results revealed clear trends in the coordinated variations of the bowing parameters depending on the constraints of the task, reflecting a common behavior as well as individual strategies. Furthermore, there were clear indications that the players adapted the bowing parameters to the physical properties of the string and the instrument, respecting the limits of the playable control parameter space.

  13. Evaluation of the location and recency of faulting near prospective surface facilities in Midway Valley, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

    2002-01-17

    Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern

  14. Evaluation of the location and recency of faulting near prospective surface facilities in Midway Valley, Nye County, Nevada

    International Nuclear Information System (INIS)

    Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

    2002-01-01

    Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern

  15. Evaluation of the Location and Recency of Faulting Near Prospective Surface Facilities in Midway Valley, Nye County, Nevada

    Science.gov (United States)

    Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

    2001-01-01

    Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern

  16. Simple analytical relations for ship bow waves

    Science.gov (United States)

    Noblesse, Francis; Delhommeau, G.?Rard; Guilbaud, Michel; Hendrix, Dane; Yang, Chi

    Simple analytical relations for the bow wave generated by a ship in steady motion are given. Specifically, simple expressions that define the height of a ship bow wave, the distance between the ship stem and the crest of the bow wave, the rise of water at the stem, and the bow wave profile, explicitly and without calculations, in terms of the ship speed, draught, and waterline entrance angle, are given. Another result is a simple criterion that predicts, also directly and without calculations, when a ship in steady motion cannot generate a steady bow wave. This unsteady-flow criterion predicts that a ship with a sufficiently fine waterline, specifically with waterline entrance angle 2, may generate a steady bow wave at any speed. However, a ship with a fuller waterline (25E) can only generate a steady bow wave if the ship speed is higher than a critical speed, defined in terms of αE by a simple relation. No alternative criterion for predicting when a ship in steady motion does not generate a steady bow wave appears to exist. A simple expression for the height of an unsteady ship bow wave is also given. In spite of their remarkable simplicity, the relations for ship bow waves obtained in the study (using only rudimentary physical and mathematical considerations) are consistent with experimental measurements for a number of hull forms having non-bulbous wedge-shaped bows with small flare angle, and with the authors' measurements and observations for a rectangular flat plate towed at a yaw angle.

  17. Entropy Generation Across Earth's Bow Shock

    Science.gov (United States)

    Parks, George K.; McCarthy, Michael; Fu, Suiyan; Lee E. s; Cao, Jinbin; Goldstein, Melvyn L.; Canu, Patrick; Dandouras, Iannis S.; Reme, Henri; Fazakerley, Andrew; hide

    2011-01-01

    Earth's bow shock is a transition layer that causes an irreversible change in the state of plasma that is stationary in time. Theories predict entropy increases across the bow shock but entropy has never been directly measured. Cluster and Double Star plasma experiments measure 3D plasma distributions upstream and downstream of the bow shock that allow calculation of Boltzmann's entropy function H and his famous H-theorem, dH/dt O. We present the first direct measurements of entropy density changes across Earth's bow shock. We will show that this entropy generation may be part of the processes that produce the non-thermal plasma distributions is consistent with a kinetic entropy flux model derived from the collisionless Boltzmann equation, giving strong support that solar wind's total entropy across the bow shock remains unchanged. As far as we know, our results are not explained by any existing shock models and should be of interests to theorists.

  18. Primary shield displacement and bowing

    International Nuclear Information System (INIS)

    Scott, K.V.

    1978-01-01

    The reactor primary shield is constructed of high density concrete and surrounds the reactor core. The inlet, outlet and side primary shields were constructed in-place using 2.54 cm (1 in) thick steel plates as the forms. The plates remained as an integral part of the shields. The elongation of the pressure tubes due to thermal expansion and pressurization is not moving through the inlet nozzle hardware as designed but is accommodated by outward displacement and bowing of the inlet and outlet shields. Excessive distortion of the shields may result in gas seal failures, intolerable helium gas leaks, increased argon-41 emissions, and shield cooling tube failures. The shield surveillance and testing results are presented

  19. Energetics of the terrestrial bow shock

    Science.gov (United States)

    Hamrin, Maria; Gunell, Herbert; Norqvist, Patrik

    2017-04-01

    The solar wind is the primary energy source for the magnetospheric energy budget. Energy can enter through the magnetopause both as kinetic energy (plasma entering via e.g. magnetic reconnection and impulsive penetration) and as electromagnetic energy (e.g. by the conversion of solar wind kinetic energy into electromagnetic energy in magnetopause generators). However, energy is extracted from the solar wind already at the bow shock, before it encounters the terrestrial magnetopause. At the bow shock the supersonic solar wind is slowed down and heated, and the region near the bow shock is known to host many complex processes, including the accelerating of particles and the generation of waves. The processes at and near the bow shock can be discussed in terms of energetics: In a generator (load) process kinetic energy is converted to (from) electromagnetic energy. Bow shock regions where the solar wind is decelerated correspond to generators, while regions where particles are energized (accelerated and heated) correspond to loads. Recently, it has been suggested that currents from the bow shock generator should flow across the magnetosheath and connect to the magnetospause current systems [Siebert and Siscoe, 2002; Lopez et al., 2011]. In this study we use data from the Magnetospheric MultiScale (MMS) mission to investigate the energetics of the bow shock and the current closure, and we compare with the MHD simulations of Lopez et al., 2011.

  20. Viols and Other Historic Bowed String Instruments

    Science.gov (United States)

    Campbell, Murray; Campbell, Patsy

    While plucked strings have been used for musical purposes since at least the third millennium BCE, the idea of sounding a string by bowing it is a much more recent development. Bowed string instruments seem to have originated in Asia toward the end of the first millennium CE, and were in widespread use in Western Europe by the end of the eleventh century. For the next three centuries many different types of bowed instrument, with a bewildering variety of names, were in common use throughout Europe.

  1. Stratigraphic and structural data for the Conasauga Group and the Rome Formation on the Copper Creek fault block near Oak Ridge, Tennessee: preliminary results from test borehole ORNL-JOY No. 2

    International Nuclear Information System (INIS)

    Haase, C.S.; Walls, E.C.; Farmer, C.D.

    1985-06-01

    To resolve long-standing problems with the stratigraphy of the Conasauga Group and the Rome Formation on the Copper Creek fault block near Oak Ridge National Laboratory (ORNL), an 828.5-m-deep test borehole was drilled. Continuous rock core was recovered from the 17.7- to 828.5-m-deep interval; temperature, caliper, neutron, gamma-ray, and acoustic (velocity and televiewer) logs were obtained. The Conasauga Group at the study site is 572.4 m thick and comprises six formations that are - in descending stratigraphic order - Maynardville Limestone (98.8 m), Nolichucky Shale (167.9 m), Maryville Limestone (141.1 m), Rogersville Shale (39.6 m), Rutledge Limestone (30.8 m), and Pumpkin Valley Shale (94.2 m). The formations are lithologically complex, ranging from clastics that consist of shales, mudstones, and siltstones to carbonates that consist of micrites, wackestones, packstones, and conglomerates. The Rome Formation is 188.1 m thick and consists of variably bedded mudstones, siltstones, and sandstones. The Rome Formation thickness represents 88.1 m of relatively undeformed section and 100.0 m of highly deformed, jumbled, and partially repeated section. The bottom of the Rome Formation is marked by a tectonic disconformity that occurs within a 46-m-thick, intensely deformed interval caused by motion along the Copper Creek fault. Results from this study establish the stratigraphy and the lithology of the Conasauga Group and the Rome Formation near ORNL and, for the first time, allow for the unambiguous correlation of cores and geophysical logs from boreholes elsewhere in the ORNL vicinity. 45 refs., 26 figs., 2 tabs

  2. Comparative review of bow shocks and magnetopauses

    International Nuclear Information System (INIS)

    Lepping, R.P.

    1984-04-01

    Bow shock and magnetopauses formation is discussed. Plasma and magnetic field environments of all the planets from Mercury to Saturn were measured. It was found that all the planets have bow shocks and almost all have a magnetopause. Venus is the only planet with no measurable intrinsic magnetic field and the solar wind interacts directly with Venus ionosphere. The bow shock characteristics depend on the changing solar wind conditions. The shape of a magnetopause or any obstacle to flow depends on the three dimensional pressure profile that it presents to the solar wind. Jupiter is unusual because of the considerable amount of plasma which is contained in its magnetosphere. Magentopause boundaries in ecliptic plane projection are modelled by segments of ellipses, matched to straight lines for the magnetotool boundaries or parabolas. Specific properties of known planetary bow shocks and magnetopauses are reviewed

  3. Bow-shaped toroidal field coils

    International Nuclear Information System (INIS)

    Bonanos, P.

    1981-05-01

    Design features of Bow-Shaped Toroidal Field Coils are described and compared with circular and D shaped coils. The results indicate that bow coils can produce higher field strengths, store more energy and be made demountable. The design offers the potential for the production of ultrahigh toroidal fields. Included are representative coil shapes and their engineering properties, a suggested structural design and an analysis of a specific case

  4. True versus apparent shapes of bow shocks

    Science.gov (United States)

    Tarango-Yong, Jorge A.; Henney, William J.

    2018-06-01

    Astrophysical bow shocks are a common result of the interaction between two supersonic plasma flows, such as winds or jets from stars or active galaxies, or streams due to the relative motion between a star and the interstellar medium. For cylindrically symmetric bow shocks, we develop a general theory for the effects of inclination angle on the apparent shape. We propose a new two-dimensional classification scheme for bow shapes, which is based on dimensionless geometric ratios that can be estimated from observational images. The two ratios are related to the flatness of the bow's apex, which we term planitude, and the openness of its wings, which we term alatude. We calculate the expected distribution in the planitude-alatude plane for a variety of simple geometrical and physical models: quadrics of revolution, wilkinoids, cantoids, and ancantoids. We further test our methods against numerical magnetohydrodynamical simulations of stellar bow shocks and find that the apparent planitude and alatude measured from infrared dust continuum maps serve as accurate diagnostics of the shape of the contact discontinuity, which can be used to discriminate between different physical models. We present an algorithm that can determine the planitude and alatude from observed bow shock emission maps with a precision of 10 to 20 per cent.

  5. Channel Bow in Boiling Water Reactors - Hot Cell Examination Results and Correlation to Measured Bow

    International Nuclear Information System (INIS)

    Mahmood, S.T.; Lin, Y.P.; Dubecky, M.A.; Edsinger, K.; Mader, E.V.

    2007-01-01

    An increase in frequency of fuel channel-control blade interference has been observed in Boiling Water Reactors (BWR) in recent years. Many of the channels leading to interference were found to bow towards the control blade in a manner that was inconsistent with the expected bow due to other effects. The pattern of bow appeared to indicate a new channel bow mechanism that differed from the predominant bow mechanism caused by differential growth due to fast-fluence gradients. In order to investigate this new type of channel bow, coupons from several channels with varying degrees of bow were returned to the GE Vallecitos Nuclear Center (VNC) for Post-Irradiation Examination (PIE). This paper describes the characteristics of channel corrosion and hydrogen pickup observed, and relates the observations to the channel exposure level, control history, and measured channel bow. The channels selected for PIE had exposures in the range of 36-48 GWd/MTU and covered a wide range of measured bow. The coupons were obtained at 4 elevations from opposing channel sides adjacent and away from the control blade. The PIE performed on these coupons included visual examination, metallography, and hydrogen concentration measurements. A new mechanism of control-blade shadow corrosion-induced channel bow was found to correlate with differences in the extent of corrosion and corresponding differences in the hydrogen concentration between opposite sides of the channels. The increased corrosion on the control blade sides was found to be dependent on the level of control early in the life of the channel. The contributions of other potential factors leading to increased channel bow and channel-control blade interference are also discussed in this paper. (authors)

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    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......) 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....

  7. Stress relaxation of thermally bowed fuel pins

    International Nuclear Information System (INIS)

    Crossland, I.G.; Speight, M.V.

    1983-01-01

    The presence of cross-pin temperature gradients in nuclear reactor fuel pins produces differential thermal expansion which, in turn, causes the fuel pin to bow elastically. If the pin is restrained in any way, such thermal bowing causes the pin to be stressed. At high temperatures these stresses can relax by creep and it is shown here that this causes the pin to suffer an additional permanent deflection, so that when the cross-pin temperature difference is removed the pin remains bowed. By representing the cylindrical pin by an equivalent I-beam, the present work examines this effect when it takes place by secondary creep. Two restraint systems are considered, and it is demonstrated that the rate of relaxation depends mainly upon the creep equation, and hence the temperature, and also the magnitude of the initial stresses. (author)

  8. Traumatic bowing of forearm and lower leg in children

    International Nuclear Information System (INIS)

    Stenstroem, R.; Gripenberg, L.; Bergius, A.-R.

    1978-01-01

    Traumatic bowing of the forearm or lower leg is reported in 31 children. It is a relatively rare condition. Bowing occurs most frequently in combination with fracture of the other bone in the same extremity. In a minority of cases a bowing deformity is a single lesion. Age distribution, degree of deformity, mechanism of origin and therapy are presented and discussed. (Auth.)

  9. Extraction of bowing parameters from violin performance combining motion capture and sensors.

    Science.gov (United States)

    Schoonderwaldt, E; Demoucron, M

    2009-11-01

    A method is described for measurement of a complete set of bowing parameters in violin performance. Optical motion capture was combined with sensors for accurate measurement of the main bowing parameters (bow position, bow velocity, bow acceleration, bow-bridge distance, and bow force) as well as secondary control parameters (skewness, inclination, and tilt of the bow). In addition, other performance features (moments of on/off in bow-string contact, string played, and bowing direction) were extracted. Detailed descriptions of the calculations of the bowing parameters, features, and calibrations are given. The described system is capable of measuring all bowing parameters without disturbing the player, allowing for detailed studies of musically relevant aspects of bow control and coordination of bowing parameters in bowed-string instrument performance.

  10. The earth's foreshock, bow shock, and magnetosheath

    Science.gov (United States)

    Onsager, T. G.; Thomsen, M. F.

    1991-01-01

    Studies directly pertaining to the earth's foreshock, bow shock, and magnetosheath are reviewed, and some comparisons are made with data on other planets. Topics considered in detail include the electron foreshock, the ion foreshock, the quasi-parallel shock, the quasi-perpendicular shock, and the magnetosheath. Information discussed spans a broad range of disciplines, from large-scale macroscopic plasma phenomena to small-scale microphysical interactions.

  11. The earth's foreshock, bow shock, and magnetosheath

    International Nuclear Information System (INIS)

    Onsager, T.G.; Thomsen, M.F.

    1991-01-01

    Studies directly pertaining to the earth's foreshock, bow shock, and magnetosheath are reviewed, and some comparisons are made with data on other planets. Topics considered in detail include the electron foreshock, the ion foreshock, the quasi-parallel shock, the quasi-perpendicular shock, and the magnetosheath. Information discussed spans a broad range of disciplines, from large-scale macroscopic plasma phenomena to small-scale microphysical interactions. 184 refs

  12. The Bowed Tube : a Virtual Violin

    OpenAIRE

    Carrillo, Alfonso P.; Bonada, Jordi

    2010-01-01

    This paper presents a virtual violin for real-time performances consisting of two modules: a violin spectral modeland a control interface. The interface is composed by asensing bow and a tube with drawn strings in substitutionof a real violin. The spectral model is driven by the bowingcontrols captured with the control interface and it is ableto predict spectral envelopes of the sound corresponding tothose controls. The envelopes are filled with harmonic andnoisy content and given to an addit...

  13. Plastic bowing of the ribs in children

    Energy Technology Data Exchange (ETDEWEB)

    Caro, P.A.; Borden, S. IV

    1988-06-01

    Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture.

  14. Plastic bowing of the ribs in children

    International Nuclear Information System (INIS)

    Caro, P.A.; Borden, S. IV

    1988-01-01

    Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture. (orig.)

  15. Radiological assessment of the femoral bowing in Japanese population

    Directory of Open Access Journals (Sweden)

    Abdelaal Ahmed Hamed Kassem

    2016-01-01

    Full Text Available Introduction: Differences in the magnitude of bowing between races are well-known characteristics of the femur. Asian races have an increased magnitude of femoral bowing but most of the orthopedic implants designed for the femur do not match this exaggerated bowing. We calculated the sagittal and coronal femoral bowing in the Japanese population at different levels of the femur and addressed its surgical significance. Material and methods: We calculated the sagittal and coronal bowing of 132 Japanese femora using CT scan of the femur. A mathematical calculation of the radius of curvature at proximal, middle, and distal regions of the femur was used to determine the degree of femoral bowing. Results: Mean sagittal bowing of the femur was 581, 188, and 161 mm for the proximal, middle, and distal thirds of the femur and mean lateral bowing was 528, 5092, and 876 mm, respectively. Mean sagittal and coronal bowing for the whole femur was 175 and 2640 mm, respectively. No correlation was found between age, gender, length of femur, and the degree of bowing. Conclusion: Our study reveals that femoral bowing in the Japanese population is 175 mm in the sagittal plane and 2640 mm in the coronal plane; these values are greater than the femoral bowing in other ethnic groups studied in the literature. This may result in varying degrees of mismatch between the western-manufactured femoral intramedullary implants and the Japanese femur. We recommend that orthopedic surgeons to accurately perform preoperative evaluation of the femoral bowing to avoid potential malalignment, rotation, and abnormal stresses between the femur and implant.

  16. Coordination in fast repetitive violin-bowing patterns.

    Science.gov (United States)

    Schoonderwaldt, Erwin; Altenmüller, Eckart

    2014-01-01

    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.

  17. 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.

  18. 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.

  19. The Evolution from Late Miocene West Salton Detachment Faulting to Cross-Cutting Pleistocene Oblique Strike-Slip Faults in the SW Salton Trough, Southern California

    OpenAIRE

    Steely, Alexander N.

    2006-01-01

    Field studies in the southwest Salton Trough between Yaqui Ridge and Borrego Mountain show that the West Salton detachment fault was active during the Pliocene and may have initiated during the latest Miocene. At Yaqui Ridge dominantly east-directed extension is recorded by slickenlines on the NW-striking detachment fault, and shows that the fault is actually a low-angle dextral oblique strike-slip fault. Crustal inheritance is responsible for the position of the fault at Yaqui Ridge, which r...

  20. Diagnosis and Fault-tolerant Control for Ship Station Keeping

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2005-01-01

    design for systems of high complexity, and also analyse the cases of cascaded or multiple faults. The paper takes as example a ship with two CP propellers, rudders and a bow thruster as actuators, and instrumentation with a suite of global position sensors, inertial navigation units and conventional gyro...

  1. A Possible Buried Impact Structure Near Bow City, Alberta

    Science.gov (United States)

    Xie, W.; Glombick, P.; Schmitt, D. R.; Bown, T. D.

    2012-12-01

    In recent years, improved exploration techniques have resulted in the serendipitous discoveries of increasing numbers of extraterrestrial impact structures in sedimentary basins around the world. Following in this tradition, a new potential impact structure centered near 50.4°N, 112.35°N in SE Alberta has been identified. The first indications of this structure appeared in careful systematic mapping of Cretaceous age sediments using public domain well log information that showed overturned and missing components in what regionally is a simple layered stratigraphy. This motivated the examination of legacy 2D seismic profiles over the area that confirmed the stratigraphic anomalies and provided new details that further supported interpretation of a potential impact structure. Further, the existence of unexpected faults through the Cretaceous Bearpaw formation had been noted as early as the 1940's in the limited outcrop available in coulees, and these as well as other complex fault structures along the Bow River outcrops were confirmed in recent field visits to the site. The 2D seismic data displays a number of listric and rose-petal faulting consistent with late stage collapse of the impact crater. Further, a seismically transparent central uplift peak is visible. Based on the results, the structure is recognized as a complex crater with a diameter of approximately 8 kilometers and, today, bottoming at a depth of 900 meters from the current surface. Currently, the age of the feature is grossly estimated to be less than 70 my on the basis of underlying undisturbed seismic reflectors. The structure may be somewhat unique in that weak coals surrounding the feature are clearly thickened indicating outward lateral sliding along shear planes through weaker layers. Work in progress includes acquisition of a high resolution seismic profile and detailed mapping of the magnetic and gravity potential fields. More detailed mapping will include searches for shock metamorphism

  2. 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.

  3. Unfaulting the Sardarapat Ridge, Southwest Armenia

    Science.gov (United States)

    Wetmore, P.; Connor, C.; Connor, L. J.; Savov, I. P.; Karakhanyan, A.

    2012-12-01

    Armenia is located near the core of contractional deformation associated with the collision between the Arabian and Eurasian tectonic plates. Several studies of this region, including portions of adjacent Georgia, Iran, and Turkey, have indicated that 1-2 mm/yr of intra-plate, north-south shortening is primarily accommodated by a network of E-W trending thrust faults, and NW-trending (dextral) and NE-trending (sinistral) strike-slip faults. One proposed fault in this network, the Sardarapat Fault (SF), was investigated as part of a regional seismic hazard assessment ahead of the installation of a replacement reactor at the Armenian Nuclear Power Plant (ANPP). The SF is primarily defined by the Sardarapat Ridge (SR), which is a WNW-trending, 40-70 m high topographic feature located just north of the Arax River and the Turkey-Armenia border. The stratigraphy comprising this ridge includes alluvium overlying several meters of lacustrine deposits above a crystal-rich basaltic lava flow that yields an Ar-Ar age of 0.9 +/- 0.02 Ma. The alluvial sediments on the ridge contain early Bronze age (3832-3470 BP) artifacts at an elevation 25 m above those of the surrounding alluvial plane. This has lead to the suggestion that the SR is bound to the south (the steepest side) by the SF, which is uplifting the ridge at a rate of 0.7 mm/yr. However, despite the prominence and trend of the ridge there are no unequivocal observations, such as scarps or exposures of fault rocks, to support the existence of the SF. The goal of the investigation of the SR area was to test various models for the formation of the ridge including faulting and combined volcanic and erosional processes. We therefore collected gravimetric, magnetic, magneto-tellurics (MT), and transient electromagnetic (TEM) data across an area of ~400 km2, and used correlations of stratigraphic data from coreholes drilled proximal to the study area to define the geometry of the contact between the basement and basin fill to

  4. H2 emission from non-stationary magnetized bow shocks

    Science.gov (United States)

    Tram, L. N.; Lesaffre, P.; Cabrit, S.; Gusdorf, A.; Nhung, P. T.

    2018-01-01

    When a fast moving star or a protostellar jet hits an interstellar cloud, the surrounding gas gets heated and illuminated: a bow shock is born that delineates the wake of the impact. In such a process, the new molecules that are formed and excited in the gas phase become accessible to observations. In this paper, we revisit models of H2 emission in these bow shocks. We approximate the bow shock by a statistical distribution of planar shocks computed with a magnetized shock model. We improve on previous works by considering arbitrary bow shapes, a finite irradiation field and by including the age effect of non-stationary C-type shocks on the excitation diagram and line profiles of H2. We also examine the dependence of the line profiles on the shock velocity and on the viewing angle: we suggest that spectrally resolved observations may greatly help to probe the dynamics inside the bow shock. For reasonable bow shapes, our analysis shows that low-velocity shocks largely contribute to H2 excitation diagram. This can result in an observational bias towards low velocities when planar shocks are used to interpret H2 emission from an unresolved bow. We also report a large magnetization bias when the velocity of the planar model is set independently. Our 3D models reproduce excitation diagrams in BHR 71 and Orion bow shocks better than previous 1D models. Our 3D model is also able to reproduce the shape and width of the broad H2 1-0S(1) line profile in an Orion bow shock (Brand et al. 1989).

  5. Faults Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Through the study of faults and their effects, much can be learned about the size and recurrence intervals of earthquakes. Faults also teach us about crustal...

  6. Structural changes in cuticles on violin bow hair caused by wear.

    Science.gov (United States)

    Yamamoto, Tomoko; Sugiyama, Shigeru

    2010-01-01

    A bow with horse tail hair is used to play the violin. New and worn-out bow hairs were observed by atomic force microscopy. The cuticles of the new bow hair were already damaged by bleach and delipidation, however the worn-out bow hairs were much more damaged and broken off by force, which relates to wearing out.

  7. Laser vibrometry measurements of vibration and sound fields of a bowed violin

    Science.gov (United States)

    Gren, Per; Tatar, Kourosh; Granström, Jan; Molin, N.-E.; Jansson, Erik V.

    2006-04-01

    Laser vibrometry measurements on a bowed violin are performed. A rotating disc apparatus, acting as a violin bow, is developed. It produces a continuous, long, repeatable, multi-frequency sound from the instrument that imitates the real bow-string interaction for a 'very long bow'. What mainly differs is that the back and forward motion of the real bow is replaced by the rotating motion with constant velocity of the disc and constant bowing force (bowing pressure). This procedure is repeatable. It is long lasting and allows laser vibrometry techniques to be used, which measure forced vibrations by bowing at all excited frequencies simultaneously. A chain of interacting parts of the played violin is studied: the string, the bridge and the plates as well as the emitted sound field. A description of the mechanics and the sound production of the bowed violin is given, i.e. the production chain from the bowed string to the produced tone.

  8. Fault finder

    Science.gov (United States)

    Bunch, Richard H.

    1986-01-01

    A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master unit for processing to determine an accurate fault distance calculation.

  9. Improvements, verifications and validations of the BOW code

    International Nuclear Information System (INIS)

    Yu, S.D.; Tayal, M.; Singh, P.N.

    1995-01-01

    The BOW code calculates the lateral deflections of a fuel element consisting of sheath and pellets, due to temperature gradients, hydraulic drag and gravity. the fuel element is subjected to restraint from endplates, neighboring fuel elements and the pressure tube. Many new features have been added to the BOW code since its original release in 1985. This paper outlines the major improvements made to the code and verification/validation results. (author)

  10. Mesoscale Surface Pressure and Temperature Features Associated with Bow Echoes

    Science.gov (United States)

    2010-01-01

    contain several bowing segments. These multiple segments could occur at the same time and be located within the same bow, such as the serial derecho ...Examination of derecho environments using proximity soundings. Wea. Forecasting, 16, 329–342. Fovell, R. G., 2002: Upstream influence of numerically...Se- vere Local Storms, Hyannis, MA, Amer. Meteor. Soc., 4.6. Johns, R. H., and W. D. Hirt, 1987: Derechos : Widespread con- vectively induced

  11. Geology along the Blue Ridge Parkway in Virginia

    Science.gov (United States)

    Carter, Mark W.; Southworth, C. Scott; Tollo, Richard P.; Merschat, Arthur J.; Wagner, Sara; Lazor, Ava; Aleinikoff, John N.

    2017-01-01

    Detailed geologic mapping and new SHRIMP (sensitive high-resolution ion microprobe) U-Pb zircon, Ar/Ar, Lu-Hf, 14C, luminescence (optically stimulated), thermochronology (fission-track), and palynology reveal the complex Mesoproterozoic to Quaternary geology along the ~350 km length of the Blue Ridge Parkway in Virginia. Traversing the boundary of the central and southern Appalachians, rocks along the parkway showcase the transition from the para-autochthonous Blue Ridge anticlinorium of northern and central Virginia to the allochthonous eastern Blue Ridge in southern Virginia. From mile post (MP) 0 near Waynesboro, Virginia, to ~MP 124 at Roanoke, the parkway crosses the unconformable to faulted boundary between Mesoproterozoic basement in the core of the Blue Ridge anticlinorium and Neoproterozoic to Cambrian metasedimentary and metavolcanic cover rocks on the western limb of the structure. Mesoproterozoic basement rocks comprise two groups based on SHRIMP U-Pb zircon geochronology: Group I rocks (1.2-1.14 Ga) are strongly foliated orthogneisses, and Group II rocks (1.08-1.00 Ga) are granitoids that mostly lack obvious Mesoproterozoic deformational features.Neoproterozoic to Cambrian cover rocks on the west limb of the anticlinorium include the Swift Run and Catoctin Formations, and constituent formations of the Chilhowee Group. These rocks unconformably overlie basement, or abut basement along steep reverse faults. Rocks of the Chilhowee Group are juxtaposed against Cambrian rocks of the Valley and Ridge province along southeast- and northwest-dipping, high-angle reverse faults. South of the James River (MP 64), Chilhowee Group and basement rocks occupy the hanging wall of the nearly flat-lying Blue Ridge thrust fault and associated splays.South of the Red Valley high-strain zone (MP 144.5), the parkway crosses into the wholly allochthonous eastern Blue Ridge, comprising metasedimentary and meta-igneous rocks assigned to the Wills Ridge, Ashe, and Alligator

  12. IRC -10414: a bow-shock-producing red supergiant star

    Science.gov (United States)

    Gvaramadze, V. V.; Menten, K. M.; Kniazev, A. Y.; Langer, N.; Mackey, J.; Kraus, A.; Meyer, D. M.-A.; Kamiński, T.

    2014-01-01

    Most runaway OB stars, like the majority of massive stars residing in their parent clusters, go through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Betelgeuse and μ Cep, are known to date. In this paper, we report the discovery of an arc-like nebula around the late M-type star IRC -10414 using the SuperCOSMOS H-alpha Survey. Our spectroscopic follow-up of IRC -10414 with the Southern African Large Telescope (SALT) showed that it is a M7 supergiant, which supports previous claims on the RSG nature of this star based on observations of its maser emission. This was reinforced by our new radio- and (sub)millimetre-wavelength molecular line observations made with the Atacama Pathfinder Experiment 12-m telescope and the Effelsberg 100-m radio telescope, respectively. The SALT spectrum of the nebula indicates that its emission is the result of shock excitation. This finding along with the arc-like shape of the nebula and an estimate of the space velocity of IRC -10414 (≈70 ± 20 km s-1) imply the bow shock interpretation for the nebula. Thus, IRC -10414 represents the third case of a bow-shock-producing RSG and the first one with a bow shock visible at optical wavelengths. We discuss the smooth appearance of the bow shocks around IRC -10414 and Betelgeuse and propose that one of the necessary conditions for stability of bow shocks generated by RSGs is the ionization of the stellar wind. Possible ionization sources of the wind of IRC -10414 are proposed and discussed.

  13. X-ray study of bow shocks in runaway stars

    Science.gov (United States)

    De Becker, M.; del Valle, M. V.; Romero, G. E.; Peri, C. S.; Benaglia, P.

    2017-11-01

    Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bow shock runaways, which constitutes a significant improvement of the sample of bow shock runaways studied in X-rays so far. A careful analysis of the data did not reveal any X-ray emission related to the bow shocks. However, X-ray emission from the stars is detected, in agreement with the expected thermal emission from stellar winds. On the basis of background measurements we derive conservative upper limits between 0.3 and 10 keV on the bow shocks emission. Using a simple radiation model, these limits together with radio upper limits allow us to constrain some of the main physical quantities involved in the non-thermal emission processes, such as the magnetic field strength and the amount of incident infrared photons. The reasons likely responsible for the non-detection of non-thermal radiation are discussed. Finally, using energy budget arguments, we investigate the detectability of inverse Compton X-rays in a more extended sample of catalogued runaway star bow shocks. From our analysis we conclude that a clear identification of non-thermal X-rays from massive runaway bow shocks requires one order of magnitude (or higher) sensitivity improvement with respect to present observatories.

  14. High resolution bathymetric and sonar images of a ridge southeast of Terceira Island (Azores plateau)

    Science.gov (United States)

    Lourenço, N.; Miranda, J. M.; Luis, J.; Silva, I.; Goslin, J.; Ligi, M.

    2003-04-01

    The Terceira rift is a oblique ultra-slow spreading system where a transtensive regime results from differential movement between Eurasian and African plates. So far no classical ridge segmentation pattern has here been observed. The predominant morphological features are fault controlled rhombic shaped basins and volcanism related morphologies like circular seamounts and volcanic ridges. We present SIMRAD EM300 (bathymetry + backscatter) images acquired over one of these ridges located SE of Terceira Island, during the SIRENA cruise (PI J. Goslin), which complements previous TOBI mosaics performed over the same area during the AZZORRE99 cruise (PI M. Ligi). The ridge presents a NW-SE orientation, it is seismically active (a seismic crisis was documented in 1997) and corresponds to the southern branch of a V shape bathymetric feature enclosing the Terceira Island and which tip is located west of the Island near the 1998 Serreta ridge eruption site. NE of the ridge, the core of the V, corresponds to the North Hirondelle basin. All this area corresponds mainly to Brunhes magnetic epoch. The new bathymetry maps reveal a partition between tectonic processes, centred in the ridge, and volcanism present at the bottom of the North Hirondelle basin. The ridge high backscatter surface is cut by a set of sub-parallel anastomosed normal faults striking between N130º and N150º. Some faults present horse-tail terminations. Fault splays sometimes link to neighbour faults defining extensional duplexes and fault wedge basins and highs of rhombic shape. The faulting geometry suggests that a left-lateral strike slip component should be present. The top of the ridge consists on an arched demi-.horst, and it is probably a volcanic structure remnant (caldera system?), existing prior to onset of the tectonic stage in the ridge. Both ridge flanks display gullies and mass wasting fans at the base of the slope. The ridge vicinities are almost exclusively composed of a grayish homogeneous

  15. Volcanism and hydrothermalism on a hotspot-influenced ridge: Comparing Reykjanes Peninsula and Reykjanes Ridge, Iceland

    Science.gov (United States)

    Pałgan, Dominik; Devey, Colin W.; Yeo, Isobel A.

    2017-12-01

    Current estimates indicate that the number of high-temperature vents (one of the primary pathways for the heat extraction from the Earth's mantle) - at least 1 per 100 km of axial length - scales with spreading rate and should scale with crustal thickness. But up to present, shallow ridge axes underlain by thick crust show anomalously low incidences of high-temperature activity. Here we compare the Reykjanes Ridge, an abnormally shallow ridge with thick crust and only one high-temperature vent known over 900 km axial length, to the adjacent subaerial Reykjanes Peninsula (RP), which is characterized by high-temperature geothermal sites confined to four volcanic systems transected by fissure swarms with young (Holocene) volcanic activity, multiple faults, cracks and fissures, and continuous seismic activity. New high-resolution bathymetry (gridded at 60 m) of the Reykjanes Ridge between 62°30‧N and 63°30‧N shows seven Axial Volcanic Ridges (AVR) that, based on their morphology, geometry and tectonic regime, are analogues for the volcanic systems and fissure swarms on land. We investigate in detail the volcano-tectonic features of all mapped AVRs and show that they do not fit with the previously suggested 4-stage evolution model for AVR construction. Instead, we suggest that AVR morphology reflects the robust or weak melt supply to the system and two (or more) eruption mechanisms may co-exist on one AVR (in contrast to 4-stage evolution model). Our interpretations indicate that, unlike on the Reykjanes Peninsula, faults on and around AVRs do not cluster in orientation domains but all are subparallel to the overall strike of AVRs (orthogonal to spreading direction). High abundance of seamounts shows that the region centered at 62°47‧N and 25°04‧W (between AVR-5 and -6) is volcanically robust while the highest fault density implies that AVR-1 and southern part of AVR-6 rather undergo period of melt starvation. Based on our observations and interpretations we

  16. Microgravity survey of the Oak Ridge K-25 Site, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Kaufmann, R.D.

    1996-05-01

    Karst features are known to exist within the carbonate bedrock of the Oak Ridge K-25 Site and may play an important role in groundwater flow and contaminant migration. This report discusses the results of a microgravity survey of the Oak Ridge K-25 Site. The main objective of the survey is to identify areas containing bedrock cavities. Secondary objectives included correlating the observed gravity to the geology and to variations in overburden thickness. The analysis includes 11 profile lines that are oriented perpendicular to the geologic strike and major structures throughout the K-25 Site. The profile lines are modeled in an effort to relate gravity anomalies to karst features such as concentrations of mud-filled cavities. Regolith thickness and density data provided by boreholes constrain the models. Areally distributed points are added to the profile lines to produce a gravity contour map of the site. In addition, data from the K-901 area are combined with data from previous surveys to produce a high resolution map of that site. The K-25 Site is located in an area of folded and faulted sedimentary rocks within the Appalachian Valley and Ridge physiographic province. Paleozoic age rocks of the Rome Formation, Knox Group, and Chickamauga Supergroup underlie the K-25 Site and contain structures that include the Whiteoak Mountain Fault, the K-25 Fault, a syncline, and an anticline. The mapped locations of the rock units and complex structures are currently derived from outcrop and well log analysis

  17. 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

    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......) 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....

  18. Bowing behavior of subassemblies in experimental fast reactor ''JOYO''

    International Nuclear Information System (INIS)

    Ikegami, T.; Mizoo, N.; Matsuno, Y.; Watari, Y.

    1984-01-01

    In JOYO, the measured power coefficients in the beginning of the operation cycle of MK-I and MK-II cores showed power dependence, while the calculation without taking account of bowing predicted little power dependence. The bowing analysis was performed in order to investigate the power dependence observed in the measured power coefficients and the following conclusions were obtained. (1) The evaluated power coefficients taking account of bowing effect agree better with measured ones than the calculated ones without taking account of bowing effect in MK-I core. (2) In MK-II core, although the analytical results show not so good agreement quantitatively with the measured power coefficients, it is suggested that they agree better depending on the uncertain parameters such as the heat generation in the reflector region, the threshold moment for leaning and the stiffness of the inner reflector. (3) It becomes clear from these results that the power dependence observed in the measured power coefficients in JOYO is due to the bowing effect. (author)

  19. Runaways and weathervanes: The shape of stellar bow shocks

    Science.gov (United States)

    Henney, W. J.; Tarango-Yong, J. A.

    2017-11-01

    Stellar bow shocks are the result of the supersonic interaction between a stellar wind and its environment. Some of these are "runaways": high-velocity stars that have been ejected from a star cluster. Others are "weather vanes", where it is the local interstellar medium itself that is moving, perhaps as the result of a champagne flow of ionized gas from a nearby HII region. We propose a new two-dimensional classification scheme for bow shapes, which is based on dimensionless geometric ratios that can be estimated from observational images. The two ratios are related to the flatness of the bow’s apex, which we term "planitude" and the openness of its wings, which we term "alatude". We calculate the inclination-dependent tracks on the planitude-alatude plane that are predicted by simple models for the bow shock shape. We also measure the shapes of bow shocks from three different observational datasets: mid-infrared arcs around hot main-sequence stars, far-infrared arcs around luminous cool stars, and emission-line arcs around proplyds and other young stars in the Orion Nebula. Clear differences are found between the different datasets in their distributions on the planitude-alatude plane, which can be used to constrain the physics of the bow shock interaction and emission mechanisms in the different classes of object.

  20. Transpressive mantle uplift at large offset oceanic transform faults

    Science.gov (United States)

    Maia, M.; Briais, A.; Brunelli, D.; Ligi, M.; Sichel, S. E.; Campos, T.

    2017-12-01

    Large-offset transform faults deform due to changes in plate motions and local processes. At the St. Paul transform, in the Equatorial Atlantic, a large body of ultramafic rocks composed of variably serpentinized and mylonitized peridotites is presently being tectonically uplifted. We recently discovered that the origin of the regional mantle uplift is linked to long-standing compressive stresses along the transform fault (1). A positive flower structure, mainly made of mylonitized mantle rocks, can be recognized on the 200 km large push-up ridge. Compressive earthquakes mechanisms reveal seismically active thrust faults on the southern flank of the ridge . The regional transpressive stress field affects a large portion of the ridge segment south of the transform, as revealed by the presence of faults and dykes striking obliquely to the direction of the central ridge axis. A smaller thrust, affecting recent sediments, was mapped south of this segment, suggesting a regional active compressive stress field. The transpressive stress field is interpreted to derive from the propagation of the Mid-Atlantic Ridge (MAR) segment into the transform domain as a response to the enhanced melt supply at the ridge axis. The propagation forced the migration and segmentation of the transform fault southward and the formation of restraining step-overs. The process started after a counterclockwise change in plate motion at 11 Ma initially resulting in extensive stress of the transform domain. A flexural transverse ridge formed in response. Shortly after plate reorganization, the MAR segment started to propagate southwards due to the interaction of the ridge and the Sierra Leone thermal anomaly. 1- Maia et al., 2016. Extreme mantle uplift and exhumation along a transpressive transform fault Nat. Geo. doi:10.1038/ngeo2759

  1. Spreading rate dependence of gravity anomalies along oceanic transform faults.

    Science.gov (United States)

    Gregg, Patricia M; Lin, Jian; Behn, Mark D; Montési, Laurent G J

    2007-07-12

    Mid-ocean ridge morphology and crustal accretion are known to depend on the spreading rate of the ridge. Slow-spreading mid-ocean-ridge segments exhibit significant crustal thinning towards transform and non-transform offsets, which is thought to arise from a three-dimensional process of buoyant mantle upwelling and melt migration focused beneath the centres of ridge segments. In contrast, fast-spreading mid-ocean ridges are characterized by smaller, segment-scale variations in crustal thickness, which reflect more uniform mantle upwelling beneath the ridge axis. Here we present a systematic study of the residual mantle Bouguer gravity anomaly of 19 oceanic transform faults that reveals a strong correlation between gravity signature and spreading rate. Previous studies have shown that slow-slipping transform faults are marked by more positive gravity anomalies than their adjacent ridge segments, but our analysis reveals that intermediate and fast-slipping transform faults exhibit more negative gravity anomalies than their adjacent ridge segments. This finding indicates that there is a mass deficit at intermediate- and fast-slipping transform faults, which could reflect increased rock porosity, serpentinization of mantle peridotite, and/or crustal thickening. The most negative anomalies correspond to topographic highs flanking the transform faults, rather than to transform troughs (where deformation is probably focused and porosity and alteration are expected to be greatest), indicating that crustal thickening could be an important contributor to the negative gravity anomalies observed. This finding in turn suggests that three-dimensional magma accretion may occur near intermediate- and fast-slipping transform faults.

  2. 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....... The 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....

  3. Wrinkle Ridges and Young Fresh Crater

    Science.gov (United States)

    2002-01-01

    (Released 10 May 2002) The Science Wrinkle ridges are a very common landform on Mars, Mercury, Venus, and the Moon. These ridges are linear to arcuate asymmetric topographic highs commonly found on smooth plains. The origin of wrinkle ridges is not certain and two leading hypotheses have been put forth by scientists over the past 40 years. The volcanic model calls for the extrusion of high viscosity lavas along linear conduits. This thick lava accumulated over these conduits and formed the ridges. The other model is tectonic and advocates that the ridges are formed by compressional faulting and folding. Today's THEMIS image is of the ridged plains of Lunae Planum located between Kasei Valles and Valles Marineris in the northern hemisphere of the planet. Wrinkle ridges are found mostly along the eastern side of the image. The broadest wrinkle ridges in this image are up to 2 km wide. A 3 km diameter young fresh crater is located near the bottom of the image. The crater's ejecta blanket is also clearly seen surrounding the sharp well-defined crater rim. These features are indicative of a very young crater that has not been subjected to erosional processes. The Story The great thing about the solar system is that planets are both alike and different. They're all foreign enough to be mysterious and intriguing, and yet familiar enough to be seen as planetary 'cousins.' By comparing them, we can learn a lot about how planets form and then evolve geologically over time. Crinkled over smooth plains, the long, wavy raised landforms seen here are called 'wrinkle ridges,' and they've been found on Mars, Mercury, Venus, and the Moon - that is, on rocky bodies that are a part of our inner solar system. We know from this observation that planets (and large-enough moons) follow similar processes. What we don't know for sure is HOW these processes work. Scientists have been trying to understand how wrinkle ridges form for 40 years, and they still haven't reached a conclusion. That

  4. Fault diagnosis

    Science.gov (United States)

    Abbott, Kathy

    1990-01-01

    The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to

  5. Ridge Regression Signal Processing

    Science.gov (United States)

    Kuhl, Mark R.

    1990-01-01

    The introduction of the Global Positioning System (GPS) into the National Airspace System (NAS) necessitates the development of Receiver Autonomous Integrity Monitoring (RAIM) techniques. In order to guarantee a certain level of integrity, a thorough understanding of modern estimation techniques applied to navigational problems is required. The extended Kalman filter (EKF) is derived and analyzed under poor geometry conditions. It was found that the performance of the EKF is difficult to predict, since the EKF is designed for a Gaussian environment. A novel approach is implemented which incorporates ridge regression to explain the behavior of an EKF in the presence of dynamics under poor geometry conditions. The basic principles of ridge regression theory are presented, followed by the derivation of a linearized recursive ridge estimator. Computer simulations are performed to confirm the underlying theory and to provide a comparative analysis of the EKF and the recursive ridge estimator.

  6. Fault tectonics and earthquake hazards in parts of southern California. [penninsular ranges, Garlock fault, Salton Trough area, and western Mojave Desert

    Science.gov (United States)

    Merifield, P. M. (Principal Investigator); Lamar, D. L.; Gazley, C., Jr.; Lamar, J. V.; Stratton, R. H.

    1976-01-01

    The author has identified the following significant results. Four previously unknown faults were discovered in basement terrane of the Peninsular Ranges. These have been named the San Ysidro Creek fault, Thing Valley fault, Canyon City fault, and Warren Canyon fault. In addition fault gouge and breccia were recognized along the San Diego River fault. Study of features on Skylab imagery and review of geologic and seismic data suggest that the risk of a damaging earthquake is greater along the northwestern portion of the Elsinore fault than along the southeastern portion. Physiographic indicators of active faulting along the Garlock fault identifiable in Skylab imagery include scarps, linear ridges, shutter ridges, faceted ridges, linear valleys, undrained depressions and offset drainage. The following previously unrecognized fault segments are postulated for the Salton Trough Area: (1) An extension of a previously known fault in the San Andreas fault set located southeast of the Salton Sea; (2) An extension of the active San Jacinto fault zone along a tonal change in cultivated fields across Mexicali Valley ( the tonal change may represent different soil conditions along opposite sides of a fault). For the Skylab and LANDSAT images studied, pseudocolor transformations offer no advantages over the original images in the recognition of faults in Skylab and LANDSAT images. Alluvial deposits of different ages, a marble unit and iron oxide gossans of the Mojave Mining District are more readily differentiated on images prepared from ratios of individual bands of the S-192 multispectral scanner data. The San Andreas fault was also made more distinct in the 8/2 and 9/2 band ratios by enhancement of vegetation differences on opposite sides of the fault. Preliminary analysis indicates a significant earth resources potential for the discrimination of soil and rock types, including mineral alteration zones. This application should be actively pursued.

  7. Study on seismic hazard assessment of large active fault systems. Evolution of fault systems and associated geomorphic structures: fault model test and field survey

    International Nuclear Information System (INIS)

    Ueta, Keichi; Inoue, Daiei; Miyakoshi, Katsuyoshi; Miyagawa, Kimio; Miura, Daisuke

    2003-01-01

    Sandbox experiments and field surveys were performed to investigate fault system evolution and fault-related deformation of ground surface, the Quaternary deposits and rocks. The summary of the results is shown below. 1) In the case of strike-slip faulting, the basic fault sequence runs from early en echelon faults and pressure ridges through linear trough. The fault systems associated with the 2000 western Tottori earthquake are shown as en echelon pattern that characterize the early stage of wrench tectonics, therefore no thoroughgoing surface faulting was found above the rupture as defined by the main shock and aftershocks. 2) Low-angle and high-angle reverse faults commonly migrate basinward with time, respectively. With increasing normal fault displacement in bedrock, normal fault develops within range after reverse fault has formed along range front. 3) Horizontal distance of surface rupture from the bedrock fault normalized by the height of the Quaternary deposits agrees well with those of model tests. 4) Upward-widening damage zone, where secondary fractures develop, forms in the handing wall side of high-angle reverse fault at the Kamioka mine. (author)

  8. Fatigue analysis of the bow structure of FPSO

    Science.gov (United States)

    Hu, Zhi-Qiang; Gao, Zhen; Gu, Yong-Ning

    2003-06-01

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

    Science.gov (United States)

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

    2016-05-09

    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.

  10. Active current sheets near the earth's bow shock

    International Nuclear Information System (INIS)

    Schwartz, S.J.; Kessel, R.L.; Brown, C.C.; Woolliscroft, L.J.C.; Dunlop, M.W.; Farrugia, C.J.; Hall, D.S.

    1988-01-01

    The authors present here an investigation of active current sheets observed by the AMPTE UK spacecraft near the Earth's bow shock, concentrating on their macroscopic features and geometry. Events selected primarily by flow directions which deviate substantially from the Sun-Earth line show similar characteristics, including their association with an underlying macroscopic current sheet and a hot central region whose flow direction is organized, at least in part, by location relative to the inferred initial intersection point between the current sheet and the bow shock. This region is flanked by edges which, according to a Rankine-Hugoniot analysis, are often fast shocks whose orientation is consistent with that expected if a bulge on the bow shock convected past the spacecraft. They have found the magnetosheath manifestations of these events which they study in detail. They suggest that these events are the direct result of the disruption and reformation of the bow shock by the passage of an interplanetary current sheet, most probably a tangential discontinuity

  11. Giotto observations of the bow shock at Comet Halley

    International Nuclear Information System (INIS)

    Formisano, V.; Amata, E.; Wilken, B.

    1986-01-01

    Preliminary results from the JPA instrument on Giotto indicate that Comet Halley, even on the flanks, has a bow shock which moves backwards and forwards over the spacecraft. To understand the structure properly will require more detailed investigation of the relationships between three particle populations, cometary ions, solar wind ions and electrons

  12. Glacial Meltwater Contirbutions to the Bow River, Alberta, Canada

    Science.gov (United States)

    Bash, E. A.; Marshall, S. J.; White, E. C.

    2009-12-01

    Assessment of glacial melt is critical for water resource management in areas which rely on glacier-fed rivers for agricultural and municipal uses. Changes in precipitation patterns coupled with current glacial retreat are altering the glacial contribution to river flow in areas such as the Andes of South America and the high ranges of Asia, as well as the Rockies of Western Canada. Alberta’s Bow River has its headwaters in the eastern slopes of the Canadian Rockies and contributes to the Nelson drainage system feeding into Hudson Bay. The Bow River basin contains several population centers, including the City of Calgary, and is heavily taxed for agricultural use. The combined effects of rapid glacial retreat in the Canadian Rockies, higher drought frequency, and increased demand are likely to heighten water stress in Southern Alberta. However, there has been little focus to date on the extent and importance of glacial meltwater in the Bow River. The Bow River contains 74.5 km2 of glacier ice, which amounts to only 0.29% of the basin. While this number is not high compared to some glacierized areas, Hopkinson and Young (1998) report that in dry years, glacier melt can provide up to 50% of late summer flows at a station in the upper reaches of the river system. We extend this work with an assessment of monthly and annual glacial contributions to the Bow River farther downstream in Calgary. Our analysis is based on mass balance, meteorological, and hydrological data that has been collected at the Haig Glacier since 2001. This data is used in conjunction with glacier coverage and hypsometric data for the remainder of the basin to estimate seasonal snow and glacial meltwater contributions to the Bow River from the glacierized fraction of the catchment. The results of this study show the percentage of total flow attributed to glacial melt to be highly variable. Glacier runoff contributes up to an order of magnitude more water to the Bow River per unit area of

  13. Small Arms of the Scythians. On the Time of Sigmoid Bow Appearance in Eastern Europe

    Directory of Open Access Journals (Sweden)

    Lukyashko Sergey Ivanovich

    2015-12-01

    Full Text Available Horse archers well-known in the ancient world used composite sigmoid bows for shooting (archery, the specific constructive features of which have been studied by the researchers. This type of a bow was convergently formed in Eastern China in the middle of the 2nd millennium B.C. and in the North Caucasus in the middle of the 4th millennium B.C. It gets transferred to the Northern Black Sea Region by the Scythians in the late 7th - early 6th centuries B.C. that resulted in the dramatic transformation of arrowheads’ types. The Greeks became aware of this weapon in the last third of the 6th century B.C. Bows can be divided into simple and complex ones. The simple bows are made from one solid bar, while the complex bows are made of several layers of different wood species. Composite bows are constructed from a few consequently connected bars. These types also include a reinforced bow – the bow springing qualities of which are reinforced by bone or tendon plates. Since the ancient masters combined different production methods, the definition of a composite reinforced bow can be found in the literature. European small arms development was focused on improving a simple bow. The strength of such bow was achieved by its size. However, massive bows are unsuitable for firing from a horse. Therefore, in cultures associated with the development of riding the search of methods of bow strength increase at the condition of reducing its size, was going on. In Asia, the focus was made on the material rather than shoulders design. As a result, complex composite bows appear in the East, which were made from several pieces of wood, connected with the central part of the handle at an angle. After the appearance of the Scythians in the middle East the angular design of bows was replaced by a sigmoid shape (scythicus acrus.

  14. Mid Ocean Ridge Processes at Very Low Melt Supply : Submersible Exploration of Smooth Ultramafic Seafloor at the Southwest Indian Ridge, 64 degree E

    Science.gov (United States)

    Cannat, M.; Agrinier, P.; Bickert, M.; Brunelli, D.; Hamelin, C.; Lecoeuvre, A.; Lie Onstad, S.; Maia, M.; Prampolini, M.; Rouméjon, S.; Vitale Brovarone, A.; Besançon, S.; Assaoui, E. M.

    2017-12-01

    Mid-ocean ridges are the Earth's most extensive and active volcanic chains. They are also, particularly at slow spreading rates, rift zones, where plate divergence is in part accommodated by faults. Large offset normal faults, also called detachments, are characteristic of slow-spreading ridges, where they account for the widespread emplacement of mantle-derived rocks at the seafloor. In most cases, these detachments occur together with ridge magmatism, with melt injection and faulting interacting to shape the newly formed oceanic lithosphere. Here, we seek to better understand these interactions and their effects on oceanic accretion by studying the end-member case of a ridge where magmatism is locally almost absent. The portion of the Southwest Indian ridge we are studying has an overal low melt supply, focused to discrete axial volcanoes, leaving almost zero melt to intervening sections of the axial valley. One of these nearly amagmatic section of the ridge, located at 64°E, has been the focus of several past cruises (sampling, mapping and seismic experiments). Here we report on the most recent cruise to the area (RV Pourquoi Pas? with ROV Victor; dec-jan 2017), during which we performed high resolution mapping, submersible exploration and sampling of the ultramafic seafloor and of sparse volcanic formations. Our findings are consistent with the flip-flop detachment hypothesis proposed for this area by Sauter et al. (Nature Geosciences, 2013; ultramafic seafloor forming in the footwall of successive detachment faults, each cutting into the footwall of the previous fault, with an opposite polarity). Our observations also document the extent and geometry of deformation in the footwall of a young axial detachment, the role of mass-wasting for the evolution of this detachment, and provide spectacular evidence for serpentinization-related hydrothermal circulation and for spatial links between faults and volcanic eruptions.

  15. Segmentation and morphology of the Central Indian Ridge between 3°S and 11°S, Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    KameshRaju, K.A.; Samudrala, K.; Drolia, R.K.; Amarnath, D.; Ramachandran, R.; Mudholkar, A.V.

    that are separated by well defined transform faults and non-transform discontinuities. Magnetic model studies qualify the ridge as a slow spreading ridge with average full spreading rates varying from 26 to 38 mm/yr. The disposition of the magnetic anomalies suggests...

  16. Magnetic field fluctuations across the Earth’s bow shock

    Directory of Open Access Journals (Sweden)

    A. Czaykowska

    Full Text Available We present a statistical analysis of 132 dayside (LT 0700-1700 bow shock crossings of the AMPTE/IRM spacecraft. We perform a superposed epoch analysis of low frequency, magnetic power spectra some minutes up-stream and downstream of the bow shock. The events are devided into categories depending on the angle θBn between bow shock normal and interplanetary magnetic field, and on plasma-β. In the foreshock upstream of the quasi-parallel bow shock, the power of the magnetic fluctuations is roughly 1 order of magnitude larger (δB ~ 4 nT for frequencies 0.01–0.04 Hz than upstream of the quasi-perpendicular shock. There is no significant difference in the magnetic power spectra upstream and downstream of the quasi-parallel bow shock; only at the shock itself, is the magnetic power enhanced by a factor of 4. This enhancement may be due to either an amplification of convecting upstream waves or to wave generation at the shock interface. On the contrary, downstream of the quasi-perpendicular shock, the magnetic wave activity is considerably higher than upstream. Down-stream of the quasi-perpendicular low-β bow shock, we find a dominance of the left-hand polarized component at frequencies just below the ion-cyclotron frequency, with amplitudes of about 3 nT. These waves are identified as ion-cyclotron waves, which grow in a low-β regime due to the proton temperature anisotropy. We find a strong correlation of this anisotropy with the intensity of the left-hand polarized component. Downstream of some nearly perpendicular (θBn ≈ 90° high-β crossings, mirror waves are identified. However, there are also cases where the conditions for mirror modes are met downstream of the nearly perpendicular shock, but no mirror waves are observed.

    Key words. Interplanetary physics (plasma waves and turbulence – Magnetospheric physics (magnetosheath; plasma waves and

  17. Magnetic field fluctuations across the Earth’s bow shock

    Directory of Open Access Journals (Sweden)

    A. Czaykowska

    2001-03-01

    Full Text Available We present a statistical analysis of 132 dayside (LT 0700-1700 bow shock crossings of the AMPTE/IRM spacecraft. We perform a superposed epoch analysis of low frequency, magnetic power spectra some minutes up-stream and downstream of the bow shock. The events are devided into categories depending on the angle θBn between bow shock normal and interplanetary magnetic field, and on plasma-β. In the foreshock upstream of the quasi-parallel bow shock, the power of the magnetic fluctuations is roughly 1 order of magnitude larger (δB ~ 4 nT for frequencies 0.01–0.04 Hz than upstream of the quasi-perpendicular shock. There is no significant difference in the magnetic power spectra upstream and downstream of the quasi-parallel bow shock; only at the shock itself, is the magnetic power enhanced by a factor of 4. This enhancement may be due to either an amplification of convecting upstream waves or to wave generation at the shock interface. On the contrary, downstream of the quasi-perpendicular shock, the magnetic wave activity is considerably higher than upstream. Down-stream of the quasi-perpendicular low-β bow shock, we find a dominance of the left-hand polarized component at frequencies just below the ion-cyclotron frequency, with amplitudes of about 3 nT. These waves are identified as ion-cyclotron waves, which grow in a low-β regime due to the proton temperature anisotropy. We find a strong correlation of this anisotropy with the intensity of the left-hand polarized component. Downstream of some nearly perpendicular (θBn ≈ 90° high-β crossings, mirror waves are identified. However, there are also cases where the conditions for mirror modes are met downstream of the nearly perpendicular shock, but no mirror waves are observed.Key words. Interplanetary physics (plasma waves and turbulence – Magnetospheric physics (magnetosheath; plasma waves and instabilities

  18. Ridge and Furrow Fields

    DEFF Research Database (Denmark)

    Møller, Per Grau

    2016-01-01

    Ridge and furrow is a specific way of ploughing which makes fields of systematic ridges and furrows like a rubbing washboard. They are part of an overall openfield system, but the focus in this paper is on the functionality of the fields. There are many indications that agro-technological reasons...... systems and the establishment of basic structures like villages (with churches) and townships and states (in northern Europe). The fields can be considered as a resilient structure lasting for 800 years, along with the same basic physical structures in society....

  19. Shipborne Magnetic Survey of San Pablo Bay and Implications on the Hayward-Rodgers Creek Fault Junction

    Science.gov (United States)

    Ponce, D. A.; Athens, N. D.; Denton, K.

    2012-12-01

    A shipborne magnetic survey of San Pablo Bay reveals a steep magnetic gradient as well as several prominent magnetic anomalies along the offshore extension of the Hayward Fault. The Hayward Fault enters San Pablo Bay at Pinole Point and potentially extends beneath San Pablo Bay for 15 km. About 1,000 line-km of shipborne magnetometer data were collected in San Pablo Bay along approximately north-east and north-west trending traverses. Shiptrack lines were spaced 200-m apart in a N55oE direction and tie-lines were spaced 500- and 1,000-m apart in a N145oE direction. Magnetometer and Geographic Positioning System (GPS) data were collected simultaneously at one-second intervals using a Geometrics G858 cesium vapor magnetometer with the sensor attached to a nonmagnetic pole extended about 2 m over the bow. Diurnal variations of the Earth's magnetic field were recorded at a ground magnetic base station and shipborne data were corrected for diurnal variations, International Geomagnetic Reference Field, cultural noise, heading errors, and leveling errors. The heading correction applied to the shipborne magnetic data accounts for a systematic shift in the magnetic readings due to the magnetic field produced by the boat and the orientation of the boat. The heading correction was determined by traversing several shiptrack lines in various azimuths in opposite directions. Magnetic measurements off the main survey lines (e.g., turns) were removed from the survey. After applying the heading correction, crossing values or the difference in values where two survey lines intersect were compared and the survey was leveled. Shipborne magnetic data reveal a prominent magnetic anomaly immediately offshore of Point Pinole that probably reflects ultramafic rocks (e.g. serpentinite), similar to those exposed in the northern part of the onshore Hayward Fault. Further to the northwest, shipborne magnetic data enhance two prominent aeromagnetic anomalies along the Hayward Fault in the

  20. Electrostatic and electromagnetic turbulence associated with the Earth's bow shock

    International Nuclear Information System (INIS)

    Rodriguez, P.

    1974-01-01

    The electric and magnetic field spectral densities of plasma waves in the earth's bow shock have been measured in the frequency range 20 Hz to 200 kHz using two 16-channel spectrum analyzers on the IMP-6 spacecraft. Electrostatic noise with a spectrum similar to the turbulence in the shock, but with lower intensities, is observed throughout the magnetosheath region, downstream of the shock. The intensity of the electrostatic component of turbulence in the bow shock increases as the upstream electron to ion temperature ratio increases, and decreases as the upstream sound velocity increases; both of these variations for the electrostatic component are consistent with ion sound wave turbulence. (U.S.)

  1. H2 profiles of C-type bow shocks

    International Nuclear Information System (INIS)

    Smith, M.D.; Brand, P.W.J.L.

    1990-01-01

    We present emission-line profiles of molecular hydrogen from curved C-shocks within molecular clouds. Shock configurations arising from the supersonic motion of jets and bullets within a dense cloud are chosen. Bow shock speeds in the range υ w = 40-200 km s -1 are investigated. Breakdown through dissociation and self-ionization restricts the C-shock section to the bow tail. We find that profiles are essentially single-peaked and narrow with full widths (at 10 per cent maximum intensity, deconvolved) of up to about 50, 40 and 30 km s -1 for cones, hemispherical caps and paraboloids, respectively. Exceptional field alignments can produce lines as wide as 75 km s -1 in the conical shock model. (author)

  2. Accretion mode of oceanic ridges governed by axial mechanical strength

    Science.gov (United States)

    Sibrant, A. L. R.; Mittelstaedt, E.; Davaille, A.; Pauchard, L.; Aubertin, A.; Auffray, L.; Pidoux, R.

    2018-04-01

    Oceanic spreading ridges exhibit structural changes as a function of spreading rate, mantle temperature and the balance of tectonic and magmatic accretion. The role that these or other processes have in governing the overall shape of oceanic ridges is unclear. Here, we use laboratory experiments to simulate ridge spreading in colloidal aqueous dispersions whose rheology evolves from purely viscous to elastic and brittle when placed in contact with a saline water solution. We find that ridge shape becomes increasingly linear with spreading rate until reaching a minimum tortuosity. This behaviour is predicted by the axial failure parameter ΠF, a dimensionless number describing the balance of brittle and plastic failure of axial lithosphere. Slow-spreading, fault-dominated and fast-spreading, fluid intrusion-dominated ridges on Earth and in the laboratory are separated by the same critical ΠF value, suggesting that the axial failure mode governs ridge geometry. Values of ΠF can also be calculated for different mantle temperatures and applied to other planets or the early Earth. For higher mantle temperatures during the Archaean, our results preclude the predicted formation of large tectonic plates at high spreading velocity.

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chevreau, F.R. [Ecole des Mines de Paris, 06904 Sophia-Antipolis (France)]. E-mail: chevreau@cindy.ensmp.fr; Wybo, J.L. [Ecole des Mines de Paris, 06904 Sophia-Antipolis (France)]. E-mail: wybo@cindy.ensmp.fr; Cauchois, D. [Process Safety Department, Sanofi-Aventis, Site de Production de Vitry sur Seine, 9 Quai Jules Guesdes, 94400 Vitry sur Seine (France)]. E-mail: didier.cauchois@sanofi-aventis.com

    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.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

    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

  6. Thermally-induced bowing of CANDU fuel elements

    International Nuclear Information System (INIS)

    Suk, H.C.; Sim, K.S.; Park, J.H.; Park, G.S.

    1995-01-01

    Considering only the thermally-induced bending moments which are generated both within the sheath and between the fuel and sheath by an asymmetric temperature distribution with respect to the axis of an element, a generalized and explicit analytical formula for the thermally-induced bending is developed in this paper, based on the cases of 1) the bending of an empty tube treated by neglecting of the fuel/sheath mechanical interaction and 2) the fuel/sheath interaction due to the pellet and sheath temperature variations. In each of the cases, the temperature asymmetries in sheath are modelled to be caused by the combined effects of (i) non-uniform coolant temperature due to imperfect coolant mixing, (ii) variable sheath/coolant heat transfer coefficient, (iii) asymmetric heat generation due to neutron flux gradients across an element and so as to inclusively cover the uniform temperature distributions within the fuel and sheath with respect to the axial centerline. Investigating the relative importance of the various parameters affecting fuel element bowing, the element bowing is found to be greatly affected with the variations of element length, sheath diameter, pellet/sheath mechanical interaction and neutron flux depression factors, pellet thermal expansion coefficient, pellet/sheath heat transfer coefficient in comparison with those of other parameters such as sheath thickness, film heat transfer coefficient, sheath thermal expansion coefficient, and sheath and pellet thermal conductivities. Also, the element bowing of the standard 37-element bundle and CANFLEX 43-element bundle for the use in CANDU-6 reactors was analyzed with the formula, which could help to demonstrate the integrity of the fuel. All the required input data for the analyses were generated in terms of the reactor operation conditions on the reactor physics, thermal hydraulics and fuel performance by using various CANDU computer codes. The analysis results indicate that the CANFLEX 43-element

  7. Bowing to the Dharma: Japanese Buddhist Women Leaders & Healers

    Directory of Open Access Journals (Sweden)

    Paula Arai

    2017-11-01

    Full Text Available The prodigious stream of Japanese Buddhist women in roles of leadership and healing extends the length of Japanese Buddhist history. This article will highlight the transformative power of bowing that helped galvanize Sōtō Zen nuns on the eve of the twentieth century and feature twentieth-century leaders who institutionalized their disciplined commitments. It will also offer a window into the creative healing practices that characterizes women’s activity in the home.

  8. Plasma waves in the Earth's foreshock, bow shock, and magnetosheath

    International Nuclear Information System (INIS)

    Onsager, T.G.

    1988-01-01

    The research presented in this dissertation is a detailed analysis of electrostatic waves in the Earth's foreshock, bow shock, and magnetosheath. The wave modes measured in these regions, the possible generation mechanisms, and the process which drive the plasma to its unstable state are investigated. The measurements used in this study were obtained from the plasma wave receiver, the particle instrument, and the magnetometer on board the Active Magnetospheric Particle Tracer Explorer (AMPTE) Ion Release Module (IRM). Electron beam mode waves have been identified in the Earth's foreshock. A technique is developed which allows the rest frame frequency and wave number of the electron beam mode waves to be determined from the measurements. The experimentally determined values are compared with theoretical predictions, and approximate limits are put on the beam temperatures. It is demonstrated that electrostatic waves are present in the bow shock and magnetosheath with frequencies above the maximum frequency for Doppler shifted ion acoustic waves, yet below the Langmuir frequency. Waves in this frequency range are tentatively identified as electron beam mode waves. This identification is based on the measured frequencies and electric field polarization directions. Data from 45 bow shock crossings are then used to investigate possible correlations between the electron beam mode waves and the near shock plasma parameters. The best correlations are found with Alfven Mach number and electron beta. Possible mechanism which might produce electron beams in the shock and magnetosheath are discussed in terms of the correlation study results

  9. 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.

  10. 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.

  11. Origins and Driving Mechanisms for Shallow Methane Accumulations on the Svyatogor Ridge, Fram Strait

    Science.gov (United States)

    Waghorn, K. A.; Bunz, S.; Plaza-Faverola, A. A.; Westvig, I. M.; Johnson, J. E.

    2015-12-01

    The Svyatogor Ridge, located west of the Knipovich Spreading Ridge (KR) and south of the Molloy Transform Fault (MTF), is hypothesized to have once been the south tip of Vestnesa Ridge; a large sediment drift that was offset during the last 2 Ma along the MTF. The sedimentary cover across Svyatogor Ridge is limited, compared to Vestnesa Ridge, and basement outcrops are identified ~850 mbsf on the apex of the ridge. Despite the limited sedimentation, and its unique location at the intersection between the KR and MTF, Svyatogor Ridge has evidence of shallow gas accumulations; a strong BSR indicating a gas hydrate and underlying free gas system, and fluid flow pathways to the seafloor culminating in pockmarks. Using a high-resolution P-Cable 3D seismic survey, 2D seismic, and multibeam bathymetry data, we investigate how tectonic and sedimentary regimes have influenced the formation of a well-developed gas hydrate system. Sedimentation related with the Vestnesa drift on Svyatogor Ridge is interpreted to have begun ~2-3 Ma. The young age of the underlying oceanic crust, and subsequent synrift sediments below drift strata, suggests gas production from early Miocene aged hydrocarbon source identified in ODP Site 909 to the west, is unlikely in this region. Additionally, given the ultra-slow, magma limited spreading regime of the KR, we do not expect significant thermogenic methane generation from shallow magmatic sources. Therefore, in addition to some microbial gas production, Johnson et al. (2015) hypothesize a contribution from an abiotic source may explain the well-developed gas hydrate system. Large-scale basement faults identified in the seismic data are interpreted as detachment faults, which have exhumed relatively young ultramafic rocks. These detachment faults act as conduits for fluid flow, allowing circulation of seawater to drive serpentinization and subsequently act as pathways for fluids and abiotic methane to reach the shallow subsurface. This work aims

  12. On the stability of bow shocks generated by red supergiants: the case of IRC -10414

    Science.gov (United States)

    Meyer, D. M.-A.; Gvaramadze, V. V.; Langer, N.; Mackey, J.; Boumis, P.; Mohamed, S.

    2014-03-01

    In this Letter, we explore the hypothesis that the smooth appearance of bow shocks around some red supergiants (RSGs) might be caused by the ionization of their winds by external sources of radiation. Our numerical simulations of the bow shock generated by IRC -10414 (the first-ever RSG with an optically detected bow shock) show that the ionization of the wind results in its acceleration by a factor of 2, which reduces the difference between the wind and space velocities of the star and makes the contact discontinuity of the bow shock stable for a range of stellar space velocities and mass-loss rates. Our best-fitting model reproduces the overall shape and surface brightness of the observed bow shock and suggests that the space velocity and mass-loss rate of IRC -10414 are ≈50 km s-1 and ≈10-6 M⊙ yr-1, respectively, and that the number density of the local interstellar medium is ≈3 cm-3. It also shows that the bow shock emission comes mainly from the shocked stellar wind. This naturally explains the enhanced nitrogen abundance in the line-emitting material, derived from the spectroscopy of the bow shock. We found that photoionized bow shocks are ≈15-50 times brighter in optical line emission than their neutral counterparts, from which we conclude that the bow shock of IRC -10414 must be photoionized.

  13. Subsurface precambrian ridge on the continental shelf of western India between Coondapoor and Kasaragod

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, V.; Rao, M.G.; SubbaRaju, L.V.

    -positions of India which are sheared by the ENE-WSW fault F1 since its breakup from Africa. The interpreted (perhaps Precambrian), are of the same age or models are shown in Fig. 8. predates the fault F1. The reactivation of some of ~0 > > Z 3o' 73* 3d 7~ 31... type and Precambrian in age. ment ridge with the Prathap Ridge (Subrahmanyam, 1989) in the slope area further Acknowledgments north of the study area suggest that these two features probably evolved at the same period. The We thank Dr. B.N. Desai...

  14. Optimal fault signal estimation

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Niemann, H.H.; Saberi, A.; Sannuti, P.

    2002-01-01

    We consider here both fault identification and fault signal estimation. Regarding fault identification, we seek either exact or almost fault identification. On the other hand, regarding fault signal estimation, we seek either $H_2$ optimal, $H_2$ suboptimal or Hinfinity suboptimal estimation. By

  15. Effective Maxillary Protraction with Tandem Traction Bow Appliance

    Directory of Open Access Journals (Sweden)

    Pravin Kumar S Marure

    2014-01-01

    Full Text Available Tandem traction bow appliance (TTBA promotes patient compliance, because it is more esthetic and comfortable than extraoral appliances. TTBA should be used only in case where maxillary deficiency and normal mandible is present. Advantages of it includes good oral hygiene, early treatment of any Class III malocclusion, optimal retention, distribution of the forces for protraction to all maxillary teeth, free mandibular movement. It can be used in conjunction with fixed appliances if necessary. This paper includes two case reports. The treatment results in both the cases demonstrated significant skeletal and dental response to TTBA therapy. Skeletal change was primarily a result of anterior movement of the maxilla.

  16. Electromagnetic ion beam instability upstream of the earth's bow shock

    International Nuclear Information System (INIS)

    Gary, S.P.; Gosling, J.T.; Forslund, D.W.

    1981-01-01

    The linear theory of the electromagnetic ion beam instability for arbitrary angles of propagation has been studied. The parameters considered in the theory are typical of the solar wind upstream of the earth's bow shock when a 'reflected' proton beam is present. Maximum growth occurs for propagation parallel to the ambient field B, but this instability also displays significant growth at wave-vectors oblique to B, Oblique, unstable modes seem to be the likely source of the compressive magnetic fluctuations recently observed in conjunction with 'diffuse' ion population. An energetic ion beam does not directly give rise to linear growth of either ion acoustic or whistler mode instabilities

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

    International Nuclear Information System (INIS)

    Russell, C.T.

    1977-01-01

    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

  18. The Role of Near-Fault Relief in Creating and Maintaining Strike-Slip Landscape Features

    Science.gov (United States)

    Harbert, S.; Duvall, A. R.; Tucker, G. E.

    2016-12-01

    Geomorphic landforms, such as shutter ridges, offset river terraces, and deflected stream channels, are often used to assess the activity and slip rates of strike-slip faults. However, in some systems, such as parts of the Marlborough Fault System (South Island, NZ), an active strike-slip fault does not leave a strong landscape signature. Here we explore the factors that dampen or enhance the landscape signature of strike-slip faulting using the Channel-Hillslope Integrated Landscape Development model (CHILD). We focus on variables affecting the length of channel offsets, which enhance the signature of strike-slip motion, and the frequency of stream captures, which eliminate offsets and reduce this signature. We model a strike-slip fault that passes through a mountain ridge, offsetting streams that drain across this fault. We use this setup to test the response of channel offset length and capture frequency to fault characteristics, such as slip rate and ratio of lateral to vertical motion, and to landscape characteristics, such as relief contrasts controlled by erodibility. Our experiments show that relief downhill of the fault, whether generated by differential uplift across the fault or by an erodibility contrast, has the strongest effect on offset length and capture frequency. This relief creates shutter ridges, which block and divert streams while being advected along a fault. Shutter ridges and the streams they divert have long been recognized as markers of strike-slip motion. Our results show specifically that the height of shutter ridges is most responsible for the degree to which they create long channel offsets by preventing stream captures. We compare these results to landscape metrics in the Marlborough Fault System, where shutter ridges are common and often lithologically controlled. We compare shutter ridge length and height to channel offset length in order to assess the influence of relief on offset channel features in a real landscape. Based on our

  19. The bowing potential of granitic rocks: rock fabrics, thermal properties and residual strain

    Science.gov (United States)

    Siegesmund, S.; Mosch, S.; Scheffzük, Ch.; Nikolayev, D. I.

    2008-10-01

    The bowing of natural stone panels is especially known for marble slabs. The bowing of granite is mainly known from tombstones in subtropical humid climate. Field inspections in combination with laboratory investigations with respect to the thermal expansion and the bowing potential was performed on two different granitoids (Cezlak granodiorite and Flossenbürg granite) which differ in the composition and rock fabrics. In addition, to describe and explain the effect of bowing of granitoid facade panels, neutron time-of-flight diffraction was applied to determine residual macro- and microstrain. The measurements were combined with investigations of the crystallographic preferred orientation of quartz and biotite. Both samples show a significant bowing as a function of panel thickness and destination temperature. In comparison to marbles the effect of bowing is more pronounced in granitoids at temperatures of 120°C. The bowing as well as the thermal expansion of the Cezlak sample is also anisotropic with respect to the rock fabrics. A quantitative estimate was performed based on the observed textures. The effect of the locked-in stresses may also have a control on the bowing together with the thermal stresses related to the different volume expansion of the rock-forming minerals.

  20. Quasi-perpendicular/quasi-parallel divisions of Earth's bow shock

    International Nuclear Information System (INIS)

    Greenstadt, E.W.

    1991-01-01

    Computer-drawn diagrams of the boundaries between quasi-perpendicular and quasi-parallel areas of Earth's bow shock are displayed for a few selected cone angles of static interplanetary magnetic field (IMF). The effect on the boundary of variable IMF in the foreshock is also discussed and shown for one nominal case. The boundaries demand caution in applying them to the realistic, dynamic conditions of the solar wind and in interpreting the effects of small cone angles on the distributions of structures at the shock. However, the calculated, first-order boundaries are helpful in defining areas of the shock where contributions from active structures inherent in quasi-parallel geometry may be distinguishable from those derived secondarily from upstream reflected ion dynamics. The boundaries are also compatible with known behavior of daytime ULF geomagnetic waves and pulsations according to models postulating that cone angle-controlled, time-dependent ULF activity around the subsolar point of the bow shock provides the source of geomagnetic excitation

  1. 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.

  2. Lunar Surface Potential Increases during Terrestrial Bow Shock Traversals

    Science.gov (United States)

    Collier, Michael R.; Stubbs, Timothy J.; Hills, H. Kent; Halekas, Jasper; Farrell, William M.; Delory, Greg T.; Espley, Jared; Freeman, John W.; Vondrak, Richard R.; Kasper, Justin

    2009-01-01

    Since the Apollo era the electric potential of the Moon has been a subject of interest and debate. Deployed by three Apollo missions, Apollo 12, Apollo 14 and Apollo 15, the Suprathermal Ion Detector Experiment (SIDE) determined the sunlit lunar surface potential to be about +10 Volts using the energy spectra of lunar ionospheric thermal ions accelerated toward the Moon. We present an analysis of Apollo 14 SIDE "resonance" events that indicate the lunar surface potential increases when the Moon traverses the dawn bow shock. By analyzing Wind spacecraft crossings of the terrestrial bow shock at approximately this location and employing current balancing models of the lunar surface, we suggest causes for the increasing potential. Determining the origin of this phenomenon will improve our ability to predict the lunar surface potential in support of human exploration as well as provide models for the behavior of other airless bodies when they traverse similar features such as interplanetary shocks, both of which are goals of the NASA Lunar Science Institute's Dynamic Response of the Environment At the Moon (DREAM) team.

  3. Electron velocity distributions near the earth's bow shock

    International Nuclear Information System (INIS)

    Feldman, W.C.; Anderson, R.C.; Bame, S.J.; Gary, S.P.; Gosling, J.T.; McComas, D.J.; Thomsen, M.F.; Paschmann, G.; Hoppe, M.M.

    1983-01-01

    A survey of two-dimensional electron velocity distributions, f(V), measured near the earth's bow shock using Los Alamos/Garching plasma instrumentation aboard ISEE 2 is presented. This survey provides clues to the mechanisms of electron thermalization within the shock and the relaxation of both the upsteam and downstream velocity distributions. First, near the foreshock boundary, fluxes of electrons having a power law shape at high energies backstream from the shock. Second, within the shock, cuts through f(V) along B. f(V), often show single maxima offset toward the magnetosheath by speeds comparable to, but larger than, the upstream thermal speed.Third, magnetosheath distributions generally have flat tops out to an energy, E 0 , with maxima substantially lower than that in the solar wind. Occasionally, cuts through f(V) along B show one and sometimes two small peaks at the edge of the flat tops making them appear concave upward. The electron distributions characteristic of these three regions are interpreted as arising from the effects of macroscopic (scale size comparable to or larger than the shock width) electric and magnetic fields and the subsequent effects of microscopic (scale size small in comparison with the shock width) fields. In particular, our results suggest that field-aligned instabilities are likely to be present in the earth's bow shock

  4. Dynamic risk analysis using bow-tie approach

    International Nuclear Information System (INIS)

    Khakzad, Nima; Khan, Faisal; Amyotte, Paul

    2012-01-01

    Accident probability estimation is a common and central step to all quantitative risk assessment methods. Among many techniques available, bow-tie model (BT) is very popular because it represent the accident scenario altogether including causes and consequences. However, it suffers a static structure limiting its application in real-time monitoring and probability updating which are key factors in dynamic risk analysis. The present work is focused on using BT approach in a dynamic environment in which the occurrence probability of accident consequences changes. In this method, on one hand, failure probability of primary events of BT, leading to the top event, are developed using physical reliability models, and constantly revised as physical parameters (e.g., pressure, velocity, dimension, etc) change. And, on the other hand, the failure probability of safety barriers of the BT are periodically updated using Bayes’ theorem as new information becomes available over time. Finally, the resulting, updated BT is used to estimate the posterior probability of the consequences which in turn results in an updated risk profile. - Highlights: ► A methodology is proposed to make bow-tie method adapted for dynamic risk analysis. ► Physical reliability models are used to revise the top event. ► Bayes’ theorem is used to update the probability of safety barriers. ► The number of accidents in sequential time intervals is used to form likelihood function. ► The risk profile is updated for varying physical parameters and for different times.

  5. Dissipation Mechanisms and Particle Acceleration at the Earth's Bow Shock

    Science.gov (United States)

    Desai, M. I.; Burch, J. L.; Broll, J. M.; Genestreti, K.; Torbert, R. B.; Ergun, R.; Wei, H.; Giles, B. L.; Russell, C. T.; Phan, T.; Chen, L. J.; Lai, H.; Wang, S.; Schwartz, S. J.; Allen, R. C.; Mauk, B.; Gingell, I.

    2017-12-01

    NASA's Magnetospheric Multiscale (MMS) mission has four spacecraft equipped with identical state-of-the-art instruments that acquire magnetic and electric field, plasma wave, and particle data at unprecedented temporal resolution to study the fundamental physics of magnetic reconnection in the Earth's magnetosphere. During Phase 1a, MMS also encountered and crossed the Earth's bow shock more than 300 times. We use burst data during 2 bow shock crossings to shed new light on key open questions regarding the formation, evolution, and dissipation mechanisms at collisionless shocks. Specifically, we focus on two events that exhibit clear differences in the ion and electron properties, the associated wave activity, and, therefore in the nature of the dissipation. In the case of a quasi-perpendicular, low beta shock crossing, we find that the dissipation processes are most likely associated with field-aligned electron beams that are coincident with high frequency electrostatic waves. On the other hand, the dissipation processes at an oblique, high beta shock crossing are largely governed by the quasi-static electric field and generation of magnetosonic whistler waves that result in perpendicular temperature anisotropy for the electrons. We also discuss the implications of these results for ion heating, reflection, and particle acceleration.

  6. Tectonics of ridge-transform intersections at the Kane fracture zone

    Science.gov (United States)

    Karson, J. A.; Dick, H. J. B.

    1983-03-01

    The Kane Transform offsets spreading-center segments of the Mid-Atlantic Ridge by about 150 km at 24° N latitude. In terms of its first-order morphological, geological, and geophysical characteristics it appears to be typical of long-offset (>100 km), slow-slipping (2 cm yr-1) ridge-ridge transform faults. High-resolution geological observations were made from deep-towed ANGUS photographs and the manned submersible ALVIN at the ridge-transform intersections and indicate similar relationships in these two regions. These data indicate that over a distance of about 20 km as the spreading axes approach the fracture zone, the two flanks of each ridge axis behave in very different ways. Along the flanks that intersect the active transform zone the rift valley floor deepens and the surface expression of volcanism becomes increasingly narrow and eventually absent at the intersection where only a sediment-covered ‘nodal basin’ exists. The adjacent median valley walls have structural trends that are oblique to both the ridge and the transform and have as much as 4 km of relief. These are tectonically active regions that have only a thin (young volcanics passes laterally into median valley walls with a simple block-faulted character where only volcanic rocks have been found. Along strike toward the fracture zone, the youngest volcanics form linear constructional volcanic ridges that transect the entire width of the fracture zone valley. These volcanics are continuous with the older-looking, slightly faulted volcanic terrain that floors the non-transform fracture zone valleys. These observations document the asymmetric nature of seafloor spreading near ridge-transform intersections. An important implication is that the crust and lithosphere across different portions of the fracture zone will have different geological characteristics. Across the active transform zone two lithosphere plate edges formed at ridge-transform corners are faulted against one another. In the non

  7. 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...... interplanetary disturbances. The results of a global 3-D MHD model were in good agreement with the Cluster observations on 17 January 2005, but they did not predict the bow shock crossings on 31 October 2003....... of three magnetopause and four bow shock models which describe them in considerably different ways using statistical methods based on observations. A new 2-D magnetopause model is introduced (based on Verigin et al., 2009) which takes into account the pressure of the compressed magnetosheath field raised...

  8. 76 FR 78234 - Medicine Bow-Routt National Forests and Thunder Basin National Grassland, Campbell County, WY...

    Science.gov (United States)

    2011-12-16

    ... DEPARTMENT OF AGRICULTURE Forest Service Medicine Bow-Routt National Forests and Thunder Basin... Supervisor, Medicine Bow-Routt National Forests and Thunder Basin National Grassland, 2250 East Richards.... Responsible Official Richard Cooksey, Deputy Forest Supervisor, Medicine Bow-Routt National Forests and...

  9. Measuring mandibular ridge reduction

    International Nuclear Information System (INIS)

    Steen, W.H.A.

    1984-01-01

    This thesis investigates the mandibular reduction in height of complete denture wearers and overdenture wearers. To follow this reduction in the anterior region as well as in the lateral sections of the mandible, an accurate and reproducible measuring method is a prerequisite. A radiologic technique offers the best chance. A survey is given of the literature concerning the resorption process after the extraction of teeth. An oblique cephalometric radiographic technique is introduced as a promising method to measure mandibular ridge reduction. The reproducibility and the accuracy of the technique are determined. The reproducibility in the positioning of the mandible is improved by the introduction of a mandibular support which permits a precise repositioning of the edentulous jaw, even after long periods of investigation. (Auth.)

  10. Information Based Fault Diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2008-01-01

    Fault detection and isolation, (FDI) of parametric faults in dynamic systems will be considered in this paper. An active fault diagnosis (AFD) approach is applied. The fault diagnosis will be investigated with respect to different information levels from the external inputs to the systems. These ...

  11. Evolution of strike-slip fault systems and associated geomorphic structures. Model test

    International Nuclear Information System (INIS)

    Ueta, Keichi

    2003-01-01

    Sandbox experiments were performed to investigate evolution of fault systems and its associated geomorphic structures caused by strike-slip motion on basement faults. A 200 cm long, 40 cm wide, 25 cm high sandbox was used in a strike-slip fault model test. Computerized X-ray tomography applied to the sandbox experiments made it possible to analyze the kinematic evaluation, as well as the three-dimensional geometry, of the faults. The deformation of the sand pack surface was analyzed by use of a laser method 3D scanner, which is a three-dimensional noncontact surface profiling instrument. A comparison of the experimental results with natural cases of active faults reveals the following: In the left-lateral strike-slip fault experiments, the deformation of the sand pack with increasing basement displacement is observed as follows. 1) In three dimensions, the right-stepping shears that have a cirque'/'shell'/'shipbody' shape develop on both sides of the basement fault. The shears on one side of the basement fault join those on the other side, resulting in helicoidal shaped shear surfaces. Shears reach the surface of the sand near or above the basement fault and en echelon Riedel shears are observed at the surface of the sand. The region between two Riedels is always an up-squeezed block. 2) lower-angle shears generally branch off from the first Riedel shears. 3) Pressure ridges develop within the zone defined by the right-stepping helicoidal shaped lower-angle shears. 4) Grabens develop between the pressure ridges. 5) Y-shears offset the pressure ridges. 6) With displacement concentrated on the central throughgoing fault zone, a liner trough developed directly above the basement fault. R1 shear and P foliation are observed in the liner trough. Such evolution of the shears and its associated structures in the fault model tests agrees well with that of strike-slip fault systems and its associated geomorphic structures. (author)

  12. Hybrid simulation techniques applied to the earth's bow shock

    Science.gov (United States)

    Winske, D.; Leroy, M. M.

    1985-01-01

    The application of a hybrid simulation model, in which the ions are treated as discrete particles and the electrons as a massless charge-neutralizing fluid, to the study of the earth's bow shock is discussed. The essentials of the numerical methods are described in detail; movement of the ions, solution of the electromagnetic fields and electron fluid equations, and imposition of appropriate boundary and initial conditions. Examples of results of calculations for perpendicular shocks are presented which demonstrate the need for a kinetic treatment of the ions to reproduce the correct ion dynamics and the corresponding shock structure. Results for oblique shocks are also presented to show how the magnetic field and ion motion differ from the perpendicular case.

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

    International Nuclear Information System (INIS)

    Towbin, Richard

    2008-01-01

    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.)

  14. 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.)

  15. Violin Pedagogy and the Physics of the Bowed String

    Science.gov (United States)

    McLeod, Alexander Rhodes

    The paper describes the mechanics of violin tone production using non-specialist language, in order to present a scientific understanding of tone production accessible to a broad readership. As well as offering an objective understanding of tone production, this model provides a powerful tool for analyzing the technique of string playing. The interaction between the bow and the string is quite complex. Literature reviewed for this study reveals that scientific investigations have provided important insights into the mechanics of string playing, offering explanations for factors which both contribute to and limit the range of tone colours and dynamics that stringed instruments can produce. Also examined in the literature review are significant works of twentieth century violin pedagogy exploring tone production on the violin, based on the practical experience of generations of teachers and performers. Hermann von Helmholtz described the stick-slip cycle which drives the string in 1863, which replaced earlier ideas about the vibration of violin strings. Later, scientists such as John Schelleng and Lothar Cremer were able to demonstrate how the mechanics of the bow-string interaction can create different tone colours. Recent research by Anders Askenfelt, Knut Guettler, and Erwin Schoonderwaldt have continued to refine earlier research in this area. The writings of Lucien Capet, Leopold Auer, Carl Flesch, Paul Rolland, Kato Havas, Ivan Galamian, and Simon Fischer are examined and analyzed. Each author describes a different approach to tone production on the violin, representing a different understanding of the underlying mechanism. Analyzing these writings within the context of a scientific understanding of tone production makes it possible to compare these approaches more consistently, and to synthesize different concepts drawn from the diverse sources evaluated.

  16. SUPRATHERMAL ELECTRONS AT SATURN'S BOW SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Masters, A.; Dougherty, M. K. [The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Sulaiman, A. H. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Sergis, N. [Office of Space Research and Technology, Academy of Athens, Soranou Efesiou 4, 11527 Athens (Greece); Stawarz, L. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Fujimoto, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Coates, A. J., E-mail: a.masters@imperial.ac.uk [Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom)

    2016-07-20

    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, <28 keV) during shock crossings, but the higher energy channels were at (or close to) background. The high-energy electron detector (MIMI-LEMMS, >18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically only the lowest energy channels (<100 keV) were above background. We show that these results are consistent with the theory in which the “injection” of thermal electrons into an acceleration process involves interaction with 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. SUPRATHERMAL ELECTRONS AT SATURN'S BOW SHOCK

    International Nuclear Information System (INIS)

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

    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, <28 keV) during shock crossings, but the higher energy channels were at (or close to) background. The high-energy electron detector (MIMI-LEMMS, >18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically only the lowest energy channels (<100 keV) were above background. We show that these results are consistent with the theory in which the “injection” of thermal electrons into an acceleration process involves interaction with 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).

  18. SPITZER OBSERVATIONS OF BOW SHOCKS AND OUTFLOWS IN RCW 38

    Energy Technology Data Exchange (ETDEWEB)

    Winston, E. [ESA-ESTEC (SRE-SA), Keplerlaan 1, 2201 AZ Noordwijk ZH (Netherlands); Wolk, S. J.; Bourke, T. L.; Spitzbart, B. [Harvard Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Megeath, S. T. [Ritter Observatory, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Ave., Toledo, OH 43606 (United States); Gutermuth, R., E-mail: ewinston@rssd.esa.int [Five Colleges Astronomy Department, Smith College, Northampton, MA 01027 (United States)

    2012-01-10

    We report Spitzer observations of five newly identified bow shocks in the massive star-forming region RCW 38. Four are visible at Infrared Array Camera (IRAC) wavelengths, the fifth is only visible at 24 {mu}m. Chandra X-ray emission indicates that winds from the central O5.5 binary, IRS 2, have caused an outflow to the northeast and southwest of the central subcluster. The southern lobe of hot ionized gas is detected in X-rays; shocked gas and heated dust from the shock front are detected with Spitzer at 4.5 and 24 {mu}m. The northern outflow may have initiated the present generation of star formation, based on the filamentary distribution of the protostars in the central subcluster. Further, the bow-shock driving star, YSO 129, is photo-evaporating a pillar of gas and dust. No point sources are identified within this pillar at near- to mid-IR wavelengths. We also report on IRAC 3.6 and 5.8 {mu}m observations of the cluster DBS2003-124, northeast of RCW 38, where 33 candidate young stellar objects (YSOs) are identified. One star associated with the cluster drives a parsec-scale jet. Two Herbig-Haro objects associated with the jet are visible at IRAC and Multiband Imaging Photometer for Spitzer (MIPS) wavelengths. The jet extends over a distance of {approx}3 pc. Assuming a velocity of 100 km s{sup -1} for the jet material gives an age of 3 Multiplication-Sign 10{sup 4} yr, indicating that the star (and cluster) are likely to be very young, with a similar or possibly younger age than RCW 38, and that star formation is ongoing in the extended RCW 38 region.

  19. SPITZER OBSERVATIONS OF BOW SHOCKS AND OUTFLOWS IN RCW 38

    International Nuclear Information System (INIS)

    Winston, E.; Wolk, S. J.; Bourke, T. L.; Spitzbart, B.; Megeath, S. T.; Gutermuth, R.

    2012-01-01

    We report Spitzer observations of five newly identified bow shocks in the massive star-forming region RCW 38. Four are visible at Infrared Array Camera (IRAC) wavelengths, the fifth is only visible at 24 μm. Chandra X-ray emission indicates that winds from the central O5.5 binary, IRS 2, have caused an outflow to the northeast and southwest of the central subcluster. The southern lobe of hot ionized gas is detected in X-rays; shocked gas and heated dust from the shock front are detected with Spitzer at 4.5 and 24 μm. The northern outflow may have initiated the present generation of star formation, based on the filamentary distribution of the protostars in the central subcluster. Further, the bow-shock driving star, YSO 129, is photo-evaporating a pillar of gas and dust. No point sources are identified within this pillar at near- to mid-IR wavelengths. We also report on IRAC 3.6 and 5.8 μm observations of the cluster DBS2003-124, northeast of RCW 38, where 33 candidate young stellar objects (YSOs) are identified. One star associated with the cluster drives a parsec-scale jet. Two Herbig-Haro objects associated with the jet are visible at IRAC and Multiband Imaging Photometer for Spitzer (MIPS) wavelengths. The jet extends over a distance of ∼3 pc. Assuming a velocity of 100 km s –1 for the jet material gives an age of 3 × 10 4 yr, indicating that the star (and cluster) are likely to be very young, with a similar or possibly younger age than RCW 38, and that star formation is ongoing in the extended RCW 38 region.

  20. Modelling the bending/bowing of composite beams such as nuclear fuel

    International Nuclear Information System (INIS)

    Tayal, M.

    1989-01-01

    Arrays of tubes are used in many engineered structures, such as in nuclear fuel bundles and in steam generators. The tubes can 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; restraint 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 shoe that the solutions of BOW are accurate. BOW's predictions for initial in-reactor bow are also consistent with two post-irradiation measurements

  1. Dominant acceleration processes of ambient energetic protons (E>= 50 keV) at the bow shock: conditions and limitations

    International Nuclear Information System (INIS)

    Anagnostopoulos, G.C.; Sarris, E.T.

    1983-01-01

    Energetic proton (Esub(p)>= 50 keV) and magnetic field observations during crossings of the Earth's Bow Shock by the IMP-7 and 8 spacecraft are incorporated in this work in order to examine the effect of the Bow Shock on a pre-existing proton population under different ''interplanetary magnetic field-Bow Shock'' configurations, as well as the conditions for the presence of the Bow Shock associated energetic proton intensity enhancements. The presented observations indicate that the dominant process for the efficient acceleration of ambient energetic particles to energies exceeding approximately 50 keV is by ''gradient-B'' drifting parallel to the induced electric field at quasi-perpendicular Bow Shocks under certain well defined limitations deriving from the finite and curved Bow Shock surface. It is shown that the proton acceleration at the Bow Shock is most efficient for high values of the upstream magnetic field (in general B 1 > 8#betta#), high upstream plasma speed and expanded Bow Shock fronts, as well as for direction of the induced electric field oriented almost parallel to the flanks of the Bow Shock, i.e. when the drift distance of protons parallel to the electric field at the shock front is considerably smaller than the local radius of curvature of the Bow Shock. The implications of the presented observations of Bow Shock crossings as to the source of the energetic proton intensity enhancements are discussed. (author)

  2. Square and bow-tie configurations in the cyclic evasion problem

    Science.gov (United States)

    Arnold, M. D.; Golich, M.; Grim, A.; Vargas, L.; Zharnitsky, V.

    2017-05-01

    Cyclic evasion of four agents on the plane is considered. There are two stationary shapes of configurations: square and degenerate bow-tie. The bow-tie is asymptotically attracting while the square is of focus-center type. Normal form analysis shows that square is nonlinearly unstable. The stable manifold consists of parallelograms that all converge to the square configuration. Based on these observations and numerical simulations, it is conjectured that any non-parallelogram non-degenerate configuration converges to the bow-tie.

  3. Bowing-reactivity trends in EBR-II assuming zero-swelling ducts

    International Nuclear Information System (INIS)

    Meneghetti, D.

    1994-01-01

    Predicted trends of duct-bowing reactivities for the Experimental Breeder Reactor II (EBR-II) are correlated with predicted row-wise duct deflections assuming use of idealized zero-void-swelling subassembly ducts. These assume no irradiation induced swellings of ducts but include estimates of the effects of irradiation-creep relaxation of thermally induced bowing stresses. The results illustrate the manners in which at-power creeps may affect subsequent duct deflections at zero power and thereby the trends of the bowing component of a subsequent power reactivity decrement

  4. Familial congenital bowing with short thick bones and metaphyseal changes, a distinct entity

    International Nuclear Information System (INIS)

    Rezza, E.; Lendvai, D.; Iannaccone, G.

    1984-01-01

    The authors describe two siblings, a male and a female, with disproportionate short stature, rhizomelic-mesomelic shortening of the limb bones, marked bowing of the femora, moderate bowing of the humeri, radii and ulnae, straight tibiae and fibulae, normal hands, flared cupped metaphyses of the tibiae, ulnae, raddi and ribs, and narrow chest. There was some improvement of the bone changes with advancing age. These two patients are similar to five other cases from the literature and strongly support Hall and Spranger's view that this pseudocampomelic condition most likely represents a distinct familial bowing syndrome. The differential diagnosis and the hereditary aspects in the two patients, are also briefly discussed. (orig.)

  5. Ocean Ridges and Oxygen

    Science.gov (United States)

    Langmuir, C. H.

    2014-12-01

    The history of oxygen and the fluxes and feedbacks that lead to its evolution through time remain poorly constrained. It is not clear whether oxygen has had discrete steady state levels at different times in Earth's history, or whether oxygen evolution is more progressive, with trigger points that lead to discrete changes in markers such as mass independent sulfur isotopes. Whatever this history may have been, ocean ridges play an important and poorly recognized part in the overall mass balance of oxidants and reductants that contribute to electron mass balance and the oxygen budget. One example is the current steady state O2 in the atmosphere. The carbon isotope data suggest that the fraction of carbon has increased in the Phanerozoic, and CO2 outgassing followed by organic matter burial should continually supply more O2 to the surface reservoirs. Why is O2 not then increasing? A traditional answer to this question would relate to variations in the fraction of burial of organic matter, but this fraction appears to have been relatively high throughout the Phanerozoic. Furthermore, subduction of carbon in the 1/5 organic/carbonate proportions would contribute further to an increasingly oxidized surface. What is needed is a flux of oxidized material out of the system. One solution would be a modern oxidized flux to the mantle. The current outgassing flux of CO2 is ~3.4*1012 moles per year. If 20% of that becomes stored organic carbon, that is a flux of .68*1012 moles per year of reduced carbon. The current flux of oxidized iron in subducting ocean crust is ~2*1012 moles per year of O2 equivalents, based on the Fe3+/Fe2+ ratios in old ocean crust compared to fresh basalts at the ridge axis. This flux more than accounts for the incremental oxidizing power produced by modern life. It also suggests a possible feedback through oxygenation of the ocean. A reduced deep ocean would inhibit oxidation of ocean crust, in which case there would be no subduction flux of oxidized

  6. Summary: beyond fault trees to fault graphs

    International Nuclear Information System (INIS)

    Alesso, H.P.; Prassinos, P.; Smith, C.F.

    1984-09-01

    Fault Graphs are the natural evolutionary step over a traditional fault-tree model. A Fault Graph is a failure-oriented directed graph with logic connectives that allows cycles. We intentionally construct the Fault Graph to trace the piping and instrumentation drawing (P and ID) of the system, but with logical AND and OR conditions added. Then we evaluate the Fault Graph with computer codes based on graph-theoretic methods. Fault Graph computer codes are based on graph concepts, such as path set (a set of nodes traveled on a path from one node to another) and reachability (the complete set of all possible paths between any two nodes). These codes are used to find the cut-sets (any minimal set of component failures that will fail the system) and to evaluate the system reliability

  7. Displacement-length ratios and contractional strains of lunar wrinkle ridges in Mare Serenitatis and Mare Tranquillitatis

    Science.gov (United States)

    Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian; Ni, Yuheng; Liu, Chunli

    2018-04-01

    Wrinkle ridges are complex thrust faults commonly found in lunar mare basalts and caused by compressional stresses from both local basin and global Moon. In this paper, we select 59 single wrinkle ridges in Mare Serenitatis and 39 single wrinkle ridges in Mare Tranquillitatis according to WAC mosaic image. For each wrinkle ridge, several topographic profiles near its midpoint are generated to measure its height and maximum displacement (Dmax) through LOLA DEM data. Then we make 2D plots of displacement-length (L) for ridge population in the two maria. The Dmax-L ratios (γ) are derived by a linear fit method according to the D-L data. The γ value (2.13 × 10-2) of ridges in Mare Tranquillitatis is higher than the γ value (1.73 × 10-2) of ridges in Mare Serenitatis. In the last, the contractional strains (ε) in Mare Serenitatis and Mare Tranquillitatis are estimated to be ∼0.36% and 0.14% (assuming the fault plane dip θ is 25°). The values of the free-air gravity anomalies in Mare Serenitatis range from 78 to 358 mGal higher than those of the gravity anomalies in Mare Tranquillitatis which range from -70 to 120 mGal. The average thickness of basalts in Mare Tranquillitatis is 400 m, while that of basalts in Mare Serenitatis is 798 m. Moreover, the average age for ridge group in Mare Serenitatis is bigger than the wrinkle ridge's age in Mare Tranquillitatis. The formation of ridge group in Mare Serenitatis takes longer time than that in Mare Serenitatis. Therefore, we think the higher value of gravity anomalies, thicker basaltic units and longer formation time for wrinkle ridge in Mare Serenitatis maybe result in the higher value of contractional strain, although the formation of Tranquillitatis basin is earlier than that of Serenitatis basin.

  8. Fault tree handbook

    International Nuclear Information System (INIS)

    Haasl, D.F.; Roberts, N.H.; Vesely, W.E.; Goldberg, F.F.

    1981-01-01

    This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation

  9. "3D_Fault_Offsets," a Matlab Code to Automatically Measure Lateral and Vertical Fault Offsets in Topographic Data: Application to San Andreas, Owens Valley, and Hope Faults

    Science.gov (United States)

    Stewart, N.; Gaudemer, Y.; Manighetti, I.; Serreau, L.; Vincendeau, A.; Dominguez, S.; Mattéo, L.; Malavieille, J.

    2018-01-01

    Measuring fault offsets preserved at the ground surface is of primary importance to recover earthquake and long-term slip distributions and understand fault mechanics. The recent explosion of high-resolution topographic data, such as Lidar and photogrammetric digital elevation models, offers an unprecedented opportunity to measure dense collections of fault offsets. We have developed a new Matlab code, 3D_Fault_Offsets, to automate these measurements. In topographic data, 3D_Fault_Offsets mathematically identifies and represents nine of the most prominent geometric characteristics of common sublinear markers along faults (especially strike slip) in 3-D, such as the streambed (minimum elevation), top, free face and base of channel banks or scarps (minimum Laplacian, maximum gradient, and maximum Laplacian), and ridges (maximum elevation). By calculating best fit lines through the nine point clouds on either side of the fault, the code computes the lateral and vertical offsets between the piercing points of these lines onto the fault plane, providing nine lateral and nine vertical offset measures per marker. Through a Monte Carlo approach, the code calculates the total uncertainty on each offset. It then provides tools to statistically analyze the dense collection of measures and to reconstruct the prefaulted marker geometry in the horizontal and vertical planes. We applied 3D_Fault_Offsets to remeasure previously published offsets across 88 markers on the San Andreas, Owens Valley, and Hope faults. We obtained 5,454 lateral and vertical offset measures. These automatic measures compare well to prior ones, field and remote, while their rich record provides new insights on the preservation of fault displacements in the morphology.

  10. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2001-01-01

    An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...... of the nominal feedback con-troller....

  11. An empirical model of the Earth's bow shock based on an artificial neural network

    Science.gov (United States)

    Pallocchia, Giuseppe; Ambrosino, Danila; Trenchi, Lorenzo

    2014-05-01

    All of the past empirical models of the Earth's bow shock shape were obtained by best-fitting some given surfaces to sets of observed crossings. However, the issue of bow shock modeling can be addressed by means of artificial neural networks (ANN) as well. In this regard, here it is presented a perceptron, a simple feedforward network, which computes the bow shock distance along a given direction using the two angular coordinates of that direction, the bow shock predicted distance RF79 (provided by Formisano's model (F79)) and the upstream alfvénic Mach number Ma. After a brief description of the ANN architecture and training method, we discuss the results of the statistical comparison, performed over a test set of 1140 IMP8 crossings, between the prediction accuracies of ANN and F79 models.

  12. 76 FR 13666 - Pitney Bowes, Inc., Mailing Solutions Management, Global Engineering Group, Including On-Site...

    Science.gov (United States)

    2011-03-14

    ...., Mailing Solutions Management, Global Engineering Group, Including On-Site Leased Workers From Guidant... workers and former workers of Pitney Bowes, Inc., Mailing Solutions Management Division, Engineering... reviewed the certification to clarify the subject worker group's identity. Additional information revealed...

  13. On numerical simulation of fuel assembly bow in pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Horváth, Ákos, E-mail: akoshorvath@t-online.hu [AREVA, AREVA NP GmbH, Paul-Gossen-Str. 100, 91052 Erlangen (Germany); Budapest University of Technology and Economics, Department of Aircraft and Ships, Stoczek Street 6, Building J, H-1111 Budapest (Hungary); Dressel, Bernd [AREVA, AREVA NP GmbH, Paul-Gossen-Str. 100, 91052 Erlangen (Germany)

    2013-12-15

    Highlights: • Simulation of fuel assembly bow by coupled CFD and finite element method. • Comparison of calculated and experimentally measured bow shapes. • Investigation of boundary condition effect on bow pattern of a fuel assembly row. • Highlighting importance of consideration of fluid–structure interaction. • Assessment of flow redistribution within the fuel assembly row model. - Abstract: Fuel assembly bow in pressurized water reactor cores is largely triggered by lateral hydraulic forces together with creep processes generated by neutron flux. A detailed understanding of the flow induced bow behaviour is, therefore, an important issue. The experimental feedbacks and laboratory tests on fuel assembly bow show that it is characterized to a high degree by fluid–structure interaction (FSI) effects, therefore, consideration of FSI is essential and indispensable in full comprehension of the bow mechanism. In the present study, coupled computational fluid dynamics (CFD) and finite element simulations are introduced, calculating fuel assembly deformation under different conditions as a quasi-stationary phenomenon. The aim has been, on the one hand, to develop such a simplified fuel assembly CFD model, which allows set up of fuel assembly rows without loosing its main hydraulic characteristic; on the other hand, to investigate the bow pattern of a given fuel assembly row under different boundary conditions. The former one has been achieved by comparing bow shapes obtained with different fuel assembly (spacer grid) modelling approaches and mesh resolutions with experimental data. In the second part of the paper a row model containing 7.5 fuel assemblies is introduced, investigating the effect of flow distribution at inlet and outlet boundary regions on fuel assembly bow behaviour. The post processing has been focused on the bow pattern, lateral hydraulic forces, and horizontal flow distribution. The results have revealed importance of consideration of

  14. Sulfide geochronlogy along the Southwest Indian Ridge

    Science.gov (United States)

    Yang, W.; Tao, C.; Li, H.; Liang, J.; Liao, S.

    2017-12-01

    Dragon Flag and Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones in the ultraslow-spreading Southwest Indian Ridge (SWIR). Ten subsamples from active and inactive vents of Dragon Flag hydrothermal field and twenty-eight subsamples from Duanqiao hydrothermal field were dated using the 230Th/238U method. Four main episodes of hydrothermal activity of Duanqiao were determined according to the restricted results: 68.9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. And sulfide samples from the nearby Dragon Flag filed at the same time and the results show that the ages of most sulfides from Dragon Flag field range from 1.496(±0.176) to 5.416 (±0.116) kyrs with the oldest age estimated at 15.997 (±0.155) kyrs Münch et al. (2001) reconstructed the evolution history of Mt. Jourdanne hydrothermal field. The age dating results indicate activity in two episodes, at 70-40 and 27-13 kyrs. The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. All these results suggest that hydrothermal activity of Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. Mt. Jourdanne is situated on an axial volcanic ridge which has both volcanic and tectonic activity. This is necessary to develop the heat source and pathways for the fluid convection, which enables the hydrothermal circulation. Hydrothermal activity in Dragon Flag Field is located next to the detachment fault termination. The detachment fault system provides a pathway for hydrothermal convection. Such style of heat source can contribute to continuous hydrothermal activity for over 1000 years. Duanqiao field is located near the central volcano and there is a hot

  15. Morphotectonics of the Carlsberg Ridge between 62 degrees 20 minutes and 66 degrees 20 minutes E, northwest Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    KameshRaju, K.A.; Chaubey, A.K.; Amarnath, D.; Mudholkar, A.

    with dominance of tectonic extension. © 2008 Elsevier B.V. All rights reserved. 1. Introduction The Carlsberg Ridge, the northwestern limb of the Indian Ocean Ridge system, defines the plate boundary between the Indian and Somalian plates. The Owen fracture zone... of the spreading centre The Carlsberg ridge is characterised by rugged topography, steep valley walls and wide rift valley floor, all characteristics of a slow spreadingridge.Thereisonlyonefirstordersegmentcausedbyawell- defined transform fault and fracture zone along...

  16. Effect of loading pattern on longitudinal bowing in flexible roll forming

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hyun; Woo, Young Yun; Hwang, Tae Woo; Han, Sang Wook; Moon, Young Hoon [School of Mechanical Engineering, Engineering Research Center for Net Shape and Die Manufacturing, Pusan National University,Busan (Korea, Republic of)

    2016-12-15

    The flexible roll forming process can be used to fabricate products with a variable cross-section profile in the longitudinal direction. Transversal nonuniformity of the longitudinal strain is one of the fundamental characteristics of blank deformation in flexible roll forming. Longitudinal bowing is a shape defect caused by transversal nonuniformity of the longitudinal strain. In this study, loading patterns in flexible roll forming are investigated in order to reduce the longitudinal bowing in a roll-formed blank. To analyze the effects of loading patterns on longitudinal bowing, two different forming schedules are implemented. In schedule 1, loading patterns with different bending angle increments are designed under fixed initial and final bending angles. In schedule 2, loading patterns with different initial bending angles under the fixed final bending angle are designed. Our results show that the bowing heights are significantly affected by the loading patterns. The bowing susceptibilities vary with blank shape such as trapezoid, convex, and concave shapes. In addition to the peak longitudinal strain at the respective roll stands, the cumulative longitudinal strain from the initial to final stands is shown to be a reliable index in predicting the tendency of longitudinal bowing.

  17. Flow performance of highly loaded axial fan with bowed rotor blades

    International Nuclear Information System (INIS)

    Chen, L; Liu, X J; Yang, A L; Dai, R

    2013-01-01

    In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved

  18. Flow performance of highly loaded axial fan with bowed rotor blades

    Science.gov (United States)

    Chen, L.; Liu, X. J.; Yang, A. L.; Dai, R.

    2013-12-01

    In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved.

  19. Anterior Femoral Bow and Possible Effect on the Stifle Joint: A Comparison between Humans and Dogs.

    Science.gov (United States)

    Ocal, M K; Sabanci, S S; Cobanoglu, M; Enercan, M

    2017-08-01

    The aim of the study was to compare the anterior bow of the femur between dogs and humans in terms of the possible impact on the stifle joint. The femoral radiographs obtained retrospectively were used to determine the angles and positions of the anterior bow in both dogs (n = 135) and humans (n = 57). Descriptive statistics and Pearson's correlation analysis were used for the statistical analyses of the variables. The mean anterior bow angle (ABA) was 18.3 ± 2.02° and 4.88 ± 1.24° in dogs and humans, respectively. The bow position was at the distal shaft in dogs (64.9 ± 2.04%) and almost at the mid-shaft of the bone (46.5 ± 5.52%) in humans. The ABA was related to the bow position in both humans and dogs. Additionally, the angle correlated with age in humans, while it was correlated with weight and breed in dogs. In conclusion, it is suggested that the anterior bow should be used as a landmark on the femoral axis for the biomechanical research of stifle joint, and dog stifle could be used as a suitable model for human knee in experimental studies for clinicians, while making sure that ethical principles are fully respected. © 2017 Blackwell Verlag GmbH.

  20. Design of fault simulator

    Energy Technology Data Exchange (ETDEWEB)

    Gabbar, Hossam A. [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology (UOIT), Ontario, L1H 7K4 (Canada)], E-mail: hossam.gabbar@uoit.ca; Sayed, Hanaa E.; Osunleke, Ajiboye S. [Okayama University, Graduate School of Natural Science and Technology, Division of Industrial Innovation Sciences Department of Intelligent Systems Engineering, Okayama 700-8530 (Japan); Masanobu, Hara [AspenTech Japan Co., Ltd., Kojimachi Crystal City 10F, Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan)

    2009-08-15

    Fault simulator is proposed to understand and evaluate all possible fault propagation scenarios, which is an essential part of safety design and operation design and support of chemical/production processes. Process models are constructed and integrated with fault models, which are formulated in qualitative manner using fault semantic networks (FSN). Trend analysis techniques are used to map real time and simulation quantitative data into qualitative fault models for better decision support and tuning of FSN. The design of the proposed fault simulator is described and applied on experimental plant (G-Plant) to diagnose several fault scenarios. The proposed fault simulator will enable industrial plants to specify and validate safety requirements as part of safety system design as well as to support recovery and shutdown operation and disaster management.

  1. Iowa Bedrock Faults

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This fault coverage locates and identifies all currently known/interpreted fault zones in Iowa, that demonstrate offset of geologic units in exposure or subsurface...

  2. Layered Fault Management Architecture

    National Research Council Canada - National Science Library

    Sztipanovits, Janos

    2004-01-01

    ... UAVs or Organic Air Vehicles. The approach of this effort was to analyze fault management requirements of formation flight for fleets of UAVs, and develop a layered fault management architecture which demonstrates significant...

  3. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1999-01-01

    The problem of fault detection and isolation of parametric faults is considered in this paper. A fault detection problem based on parametric faults are associated with internal parameter variations in the dynamical system. A fault detection and isolation method for parametric faults is formulated...

  4. Fault tolerant computing systems

    International Nuclear Information System (INIS)

    Randell, B.

    1981-01-01

    Fault tolerance involves the provision of strategies for error detection damage assessment, fault treatment and error recovery. A survey is given of the different sorts of strategies used in highly reliable computing systems, together with an outline of recent research on the problems of providing fault tolerance in parallel and distributed computing systems. (orig.)

  5. Fault zone hydrogeology

    Science.gov (United States)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and address remaining challenges by co-locating study areas, sharing approaches and fusing data, developing conceptual models from hydrogeologic data, numerical modeling, and training interdisciplinary scientists.

  6. Performance based fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2002-01-01

    Different aspects of fault detection and fault isolation in closed-loop systems are considered. It is shown that using the standard setup known from feedback control, it is possible to formulate fault diagnosis problems based on a performance index in this general standard setup. It is also shown...

  7. 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

  8. Geochemical implications of gabbro from the slow-spreading Northern Central Indian Ocean Ridge, Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ray, Dwijesh; Misra, S.; Banerjee, R.; Weis, D.

    ., 1989) and the dynamics of crystallization of plutonic rocks (Bloomer et al., 1989; Meyer et al., 1989). The recovery of gabbroic rocks is mostly restricted to major transform faults or fracture zones transecting mid-ocean ridges, e.g., Mid... gabbro of Indian Ocean Ridge System (Fig 1) is ODP leg 118 from SWIR (Dick et al., 2002; Coogan et al, 2001). Gabbro from Leg 179 (ODP Hole 735B from Atlantis II fracture zone, Dick et al., 2000) and Leg 179 (Hole 1105A) near Leg 118 have also been...

  9. Polarized bow shocks reveal features of the winds and environments of massive stars

    Science.gov (United States)

    Shrestha, Manisha

    2018-01-01

    Massive stars strongly affect their surroundings through their energetic stellar winds and deaths as supernovae. The bow shock structures created by fast-moving massive stars contain important information about the winds and ultimate fates of these stars as well as their local interstellar medium (ISM). Since bow shocks are aspherical, the light scattered in the dense shock material becomes polarized. Analyzing this polarization reveals details of the bow shock geometry as well as the composition, velocity, density, and albedo of the scattering material. With these quantities, we can constrain the properties of the stellar wind and thus the evolutionary state of the star, as well as the dust composition of the local ISM.In my dissertation research, I use a Monte Carlo radiative transfer code that I optimized to simulate the polarization signatures produced by both resolved and unresolved stellar wind bow shocks (SWBS) illuminated by a central star and by shock emission. I derive bow shock shapes and densities from published analytical calculations and smooth particle hydrodynamic (SPH) models. In the case of the analytical SWBS and electron scattering, I find that higher optical depths produce higher polarization and position angle rotations at specific viewing angles compared to theoretical predictions for low optical depths. This is due to the geometrical properties of the bow shock combined with multiple scattering effects. For dust scattering, the polarization signature is strongly affected by wavelength, dust grain properties, and viewing angle. The behavior of the polarization as a function of wavelength in these cases can distinguish among different dust models for the local ISM. In the case of SPH density structures, I investigate how the polarization changes as a function of the evolutionary phase of the SWBS. My dissertation compares these simulations with polarization data from Betelgeuse and other massive stars with bow shocks. I discuss the

  10. Kinematics of Post-obduction Deformation of the Tertiary Ridge at Al-Khod Village (Muscat, Oman

    Directory of Open Access Journals (Sweden)

    Andreas Scharf

    2016-11-01

    Full Text Available Structural investigations in post-obductional Paleocene to Eocene limestones of the Tertiary Ridge reveal a ~1 km long WNW-ESE striking strike-slip fault system within the ridge, consisting of two main sub-parallel, strike-slip faults. Considering the geometry of the Harding Strain Ellipse, the orientation of structures between the two strike-slip faults (e.g., Riedel shears, folds, reverse faults point to left-lateral motion. The abundance of large-scale folds (up to 100 m in wave length and amplitude between the two strike-slip faults led us to the interpretation of transpressive conditions in a first approximation. Moreover, the Tertiary Ridge of the study area consists of three distinct structural domains. The faults of Domain A and C are oriented WNW-ESE, but the trend of the faults in the central Domain B differs by ~10°. The left-lateral strike-slip fault system exists only in Domain B. We propose that the direction of greatest stress during Miocene plate convergence (sigma 1 was oriented 032°/212°. Considering the trend of the strike-slip zone and the orientation of sigma 1, the left-lateral motion must have been transpressive. Sigma 1 is perpendicularly oriented to the domains A and C. Prior to the Miocene D2 compressional event the study area was affected by a D1 extensional event, related to the opening of the Red Sea and the Gulf of Aden or to gravity-driven normal faulting. The D2 compressional/transpressional structures of the Miocene are reactivating the D1 structures of the Oligocene.

  11. The existence and nature of the interstellar bow shock

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Jaffel, Lotfi [UPMC Univ Paris 06, UMR7095, Institut d' Astrophysique de Paris, F-75014, Paris (France); Strumik, M.; Ratkiewicz, R.; Grygorczuk, J., E-mail: bjaffel@iap.fr [Space Research Centre, Polish Academy of Sciences, Bartycka 18A, 00-716 Warsaw (Poland)

    2013-12-20

    We report a new diagnosis of two different states of the local interstellar medium (LISM) near our solar system by using a sensitivity study constrained by several distinct and complementary observations of the LISM, solar wind, and inner heliosphere. Assuming the Interstellar Boundary Explorer (IBEX) He flow parameters for the LISM, we obtain a strength of ∼2.7 ± 0.2 μG and a direction pointing away from galactic coordinates (28, 52) ± 3° for the interstellar magnetic field as a result of fitting Voyager 1 and Voyager 2 in situ plasma measurements and IBEX energetic neutral atoms ribbon. When using Ulysses parameters for the LISM He flow, we recently reported the same direction but with a strength of 2.2 ± 0.1 μG. First, we notice that with Ulysses He flow, our solution is in the expected hydrogen deflection plane (HDP). In contrast, for the IBEX He flow, the solution is ∼20° away from the corresponding HDP plane. Second, the long-term monitoring of the interplanetary H I flow speed shows a value of ∼26 km s{sup –1} measured upwind from the Doppler shift in the strong Lyα sky background emission line. All elements of the diagnosis seem therefore to support Ulysses He flow parameters for the interstellar state. In that frame, we argue that reliable discrimination between superfast, subfast, or superslow states of the interstellar flow should be based on most existing in situ and remote observations used together with global modeling of the heliosphere. For commonly accepted LISM ionization rates, we show that a fast interstellar bow shock should be standing off upstream of the heliopause.

  12. Electric field measurements at subcritical, oblique bow shock crossings

    International Nuclear Information System (INIS)

    Wygant, J.R.; Bensadoun, M.; Mozer, F.S.

    1987-01-01

    Electric field measurements at oblique, subcritical bow shock crossings are presented from the ISEE 1 University of California, Berkeley, double-probe electric field experiment. The measurements averaged over the 3-s spin period of the spacecraft provide the first observations of the large-scale (100 km) laminar oscillations in the longitudinal component of the electric field associated with the whistler precursor which is characteristic of these dispersive shocks. The amplitude of the oscillations increases from ∼0.5 mV/m to a maximum of 6 mV/m across the magnetic ramp of the shock (directed along the shock normal). The calculated electric potential drops across the shocks varied from 340 to 550 volts, which is 40-60% of the observed loss of kinetic energy associated with the bulk flow of the ions. These measurements suggest that at these shocks the additional deceleration of incident ions is due to the Lorentz force. The contributions to the normal component of the large-scale electric field at the shock due to the parallel and perpendicular components (relative to the magnetic field) of the electric field are evaluated. It is shown that the perpendicular component of the electric field dominates, accounting for most of the cross-shock potential, but that there is a nonnegligible parallel component. This large-scale parallel component has a magnitude of 1-2 mV/m which sometimes results in a potential well for electrons with a depth of ∼150 eV. It is experimentally demonstrated that the dominance of the perpendicular over the parallel component of the electric field resulted in a correlation between the longitudinal component of the large-scale electric field and the fluctuations in the magnetic field component perpendicular to the coplanarity plane

  13. 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.

  14. 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.

  15. Blade bowing effects on radial equilibrium of inlet flow in axial compressor cascades

    Directory of Open Access Journals (Sweden)

    Han XU

    2017-10-01

    Full Text Available The circumferentially averaged equation of the inlet flow radial equilibrium in axial compressor was deduced. It indicates that the blade inlet radial pressure gradient is closely related to the radial component of the circumferential fluctuation (CF source item. Several simplified cascades with/without aerodynamic loading were numerically studied to investigate the effects of blade bowing on the inlet flow radial equilibrium. A data reduction program was conducted to obtain the CF source from three-dimensional (3D simulation results. Flow parameters at the passage inlet were focused on and each term in the radial equilibrium equation was discussed quantitatively. Results indicate that the inviscid blade force is the inducement of the inlet CF due to geometrical asymmetry. Blade bowing induces variation of the inlet CF, thus changes the radial pressure gradient and leads to flow migration before leading edge (LE in the cascades. Positive bowing drives the inlet flow to migrate from end walls to mid-span and negative bowing turns it to the reverse direction to build a new equilibrium. In addition, comparative studies indicate that the inlet Mach number and blade loading can efficiently impact the effectiveness of blade bowing on radial equilibrium in compressor design.

  16. Multispacecraft observations of energetic ions upstream and downstream of the bow shock

    International Nuclear Information System (INIS)

    Scholer, M.; Mobius, E.; Kistler, L.M.; Klecker, B.; Ipavich, F.M.; Department of Physics and Astronomy, University of Maryland, College Park)

    1989-01-01

    We present simultaneous measurements of energetic protons and alpha particles inside and outside of the magnetopause, immediately upstream, and downstream as well as further upstream of the bow shock. A comparison between the intensity at the bow shock and further upstream results in an e-folding distance at 30 keV of similar to 6.2 R/sub E/. After transformation of the angular distribution into the solar wind frame a diffusion coefficeint of κ/sub parallel/similar to 3 R/sub E/ is obtained from the anisotropy and the intensity gradient. Immediately downstream of the bow shock the anisotropy in the shock frame is directed toward the magnetopause. After transformation into the plasma rest frame the distribution is isotropic. The intensity in the magnetosheath just outside the magnetopause is smaller than the intensity behind the bow shock. Thus, in the magnetosheath there is no gradient or streaming in the upstream direction. The spectra, intensities, and relative abundances in the magnetosheath and inside the magnetosphere are totally different. These observations are consistent with first order Fermi acceleration at the bow shock and subsequent downstream convection, and exclude a magnetospheric source for these particles. Copyright American Geophysical Union 1989

  17. BOWS (bioinformatics open web services) to centralize bioinformatics tools in web services.

    Science.gov (United States)

    Velloso, Henrique; Vialle, Ricardo A; Ortega, J Miguel

    2015-06-02

    Bioinformaticians face a range of difficulties to get locally-installed tools running and producing results; they would greatly benefit from a system that could centralize most of the tools, using an easy interface for input and output. Web services, due to their universal nature and widely known interface, constitute a very good option to achieve this goal. Bioinformatics open web services (BOWS) is a system based on generic web services produced to allow programmatic access to applications running on high-performance computing (HPC) clusters. BOWS intermediates the access to registered tools by providing front-end and back-end web services. Programmers can install applications in HPC clusters in any programming language and use the back-end service to check for new jobs and their parameters, and then to send the results to BOWS. Programs running in simple computers consume the BOWS front-end service to submit new processes and read results. BOWS compiles Java clients, which encapsulate the front-end web service requisitions, and automatically creates a web page that disposes the registered applications and clients. Bioinformatics open web services registered applications can be accessed from virtually any programming language through web services, or using standard java clients. The back-end can run in HPC clusters, allowing bioinformaticians to remotely run high-processing demand applications directly from their machines.

  18. 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.

  19. The Milky Way Project: A Citizen Science Catalog of Infrared Bow Shock Nebulae

    Science.gov (United States)

    Dixon, Don; Jayasinghe, Tharindu; Povich, Matthew S.

    2017-01-01

    We present preliminary results from the first citizen-science search for infrared stellar-wind bow shock candidates. This search uses the Milky Way project, hosted by the Zooniverse, an online platform with over 1 million volunteer citizen scientists. Milky Way Project volunteers examine 77,000 randomly-distributed Spitzer image cutouts at varying zoom levels. Volunteers mark the infrared arc of potential bow shock candidates as well as the star likely driving the nebula. We produce lists of candidates from bow shocks flagged by multiple volunteers, which after merging and final visual review form the basis for our catalog. Comparing our new catalog to a recently-published catalog of 709 infrared bow shock candidates identified by a small team of (primarily undergraduate) researchers will allow us to assess the effectiveness of citizen science for this type of search and should yield a more complete catalog. Planned studies using these large catalogs will improve constraints on the mass-loss rates for the massive stars that create these bow shock nebulae. Mass-loss rates are highly uncertain but are a critical component of evolutionary models for massive stars. This work is supported by the National Science Foundation under grants CAREER-1454334, AST-1411851 (RUI) and AST-1412845.

  20. Fluid flow and permeabilities in basement fault zones

    Science.gov (United States)

    Hollinsworth, Allan; Koehn, Daniel

    2017-04-01

    Fault zones are important sites for crustal fluid flow, specifically where they cross-cut low permeability host rocks such as granites and gneisses. Fluids migrating through fault zones can cause rheology changes, mineral precipitation and pore space closure, and may alter the physical and chemical properties of the host rock and deformation products. It is therefore essential to consider the evolution of permeability in fault zones at a range of pressure-temperature conditions to understand fluid migration throughout a fault's history, and how fluid-rock interaction modifies permeability and rheological characteristics. Field localities in the Rwenzori Mountains, western Uganda and the Outer Hebrides, north-west Scotland, have been selected for field work and sample collection. Here Archaean-age TTG gneisses have been faulted within the upper 15km of the crust and have experienced fluid ingress. The Rwenzori Mountains are an anomalously uplifted horst-block located in a transfer zone in the western rift of the East African Rift System. The north-western ridge is characterised by a tectonically simple western flank, where the partially mineralised Bwamba Fault has detached from the Congo craton. Mineralisation is associated with hydrothermal fluids heated by a thermal body beneath the Semliki rift, and has resulted in substantial iron oxide precipitation within porous cataclasites. Non-mineralised faults further north contain foliated gouges and show evidence of leaking fluids. These faults serve as an analogue for faults associated with the Lake Albert oil and gas prospects. The Outer Hebrides Fault Zone (OHFZ) was largely active during the Caledonian Orogeny (ca. 430-400 Ma) at a deeper crustal level than the Ugandan rift faults. Initial dry conditions were followed by fluid ingress during deformation that controlled its rheological behaviour. The transition also altered the existing permeability. The OHFZ is a natural laboratory in which to study brittle fault

  1. Oak Ridge Leadership Computing Facility (OLCF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Oak Ridge Leadership Computing Facility (OLCF) was established at Oak Ridge National Laboratory in 2004 with the mission of standing up a supercomputer 100 times...

  2. Oak Ridge Geochemical Reconnaissance Program

    International Nuclear Information System (INIS)

    Arendt, J.W.

    1977-03-01

    The Oak Ridge reconnaissance program is responsible for the geochemical survey in a 12-state area covering Texas, Oklahoma, Kansas, Nebraska, South Dakota, North Dakota, Minnesota, Wisconsin, Michigan, Iowa, Indiana, and Illinois as part of the National Uranium Resource Evaluation Program. The program concept is outlined and the planning and organization of the program is discussed

  3. Fault tolerant control for uncertain systems with parametric faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2006-01-01

    A fault tolerant control (FTC) architecture based on active fault diagnosis (AFD) and the YJBK (Youla, Jarb, Bongiorno and Kucera)parameterization is applied in this paper. Based on the FTC architecture, fault tolerant control of uncertain systems with slowly varying parametric faults...... is investigated. Conditions are given for closed-loop stability in case of false alarms or missing fault detection/isolation....

  4. AMPLITUDES OF DISJUNCTIVE DISLOCATIONS IN THE KNIPOVICH RIDGE FLANKS (NORTHERN ATLANTIC AS AN INDICATOR OF MODERN REGIONAL GEODYNAMICS

    Directory of Open Access Journals (Sweden)

    S. Yu. Sokolov

    2017-01-01

    Full Text Available This article presents the first map showing the vertical amplitudes of modern disjunctive dislocations inNorthern Atlantic, based on the estimated phase shifts of reflected waves recorded by high-frequency seismic acoustic surveys. The amplitude distribution pattern is mosaic with alternating areas of compression and extension in the flanks of the Knipovich rift system. The modern structure of the Knipovich Ridge, including two strike-slip faults, represents a local rift in the pull-apart setting. The asymmetry of stresses and the presence of compression in the ridge flanks is evidenced by the distribution of the focal mechanisms of strong earthquakes related to reverse faults. In the southeastern Knipovich Ridge, tectonic activity is marked by the asymmetric pattern of the epicenters of small earthquakes.

  5. Motion in the north Iceland volcanic rift zone accommodated by bookshelf faulting

    Science.gov (United States)

    Green, Robert G.; White, Robert S.; Greenfield, Tim

    2014-01-01

    Along mid-ocean ridges the extending crust is segmented on length scales of 10-1,000km. Where rift segments are offset from one another, motion between segments is accommodated by transform faults that are oriented orthogonally to the main rift axis. Where segments overlap, non-transform offsets with a variety of geometries accommodate shear motions. Here we use micro-seismic data to analyse the geometries of faults at two overlapping rift segments exposed on land in north Iceland. Between the rift segments, we identify a series of faults that are aligned sub-parallel to the orientation of the main rift. These faults slip through left-lateral strike-slip motion. Yet, movement between the overlapping rift segments is through right-lateral motion. Together, these motions induce a clockwise rotation of the faults and intervening crustal blocks in a motion that is consistent with a bookshelf-faulting mechanism, named after its resemblance to a tilting row of books on a shelf. The faults probably reactivated existing crustal weaknesses, such as dyke intrusions, that were originally oriented parallel to the main rift and have since rotated about 15° clockwise. Reactivation of pre-existing, rift-parallel weaknesses contrasts with typical mid-ocean ridge transform faults and is an important illustration of a non-transform offset accommodating shear motion between overlapping rift segments.

  6. Structural character of the northern segment of the Paintbrush Canyon fault, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Dickerson, R.P.; Spengler, R.W.

    1994-01-01

    Detailed mapping of exposed features along the northern part of the Paintbrush Canyon fault was initiated to aid in construction of the computer-assisted three-dimensional lithostratigraphic model of Yucca Mountain, to contribute to kinematic reconstruction of the tectonic history of the Paintbrush Canyon fault, and to assist in the interpretation of geophysical data from Midway Valley. Yucca Mountain is segmented into relatively intact blocks of east-dipping Miocene volcanic strata, bounded by north-striking, west-dipping high-angle normal faults. The Paintbrush Canyon fault, representing the easternmost block-bounding normal fault, separates Fran Ridge from Midway Valley and continues northward across Yucca Wash to at least the southern margin of the Timber Mountain Caldera complex. South of Yucca Wash, the Paintbrush Canyon Fault is largely concealed beneath thick Quaternary deposits. Bedrock exposures to the north reveal a complex fault, zone, displaying local north- and west-trending grabens, and rhombic pull-apart features. The fault scarp, discontinuously exposed along a mapped length of 8 km north of Yucca Wash, dips westward by 41 degrees to 74 degrees. Maximum vertical offset of the Rhyolite of Comb Peak along the fault measures about 210 m in Paintbrush Canyon and, on the basis of drill hole information, vertical offset of the Topopoah Spring Tuff is about 360 m near the northern part of Fran Ridge. Observed displacement along the fault in Paintbrush Canyon is down to the west with a component of left-lateral oblique slip. Unlike previously proposed tectonic models, strata adjacent to the fault dip to the east. Quaternary deposits do not appear displaced along the fault scarp north of Yucca Wash, but are displaced in trenches south of Yucca Wash

  7. Hydrothermal activity at slow-spreading ridges: variability and importance of magmatic controls

    Science.gov (United States)

    Escartin, Javier

    2016-04-01

    Hydrothermal activity along mid-ocean ridge axes is ubiquitous, associated with mass, chemical, and heat exchanges between the deep lithosphere and the overlying envelopes, and sustaining chemiosynthetic ecosystems at the seafloor. Compared with hydrothermal fields at fast-spreading ridges, those at slow spreading ones show a large variability as their location and nature is controlled or influenced by several parameters that are inter-related: a) tectonic setting, ranging from 'volcanic systems' (along the rift valley floor, volcanic ridges, seamounts), to 'tectonic' ones (rift-bounding faults, oceanic detachment faults); b) the nature of the host rock, owing to compositional heterogeneity of slow-spreading lithosphere (basalt, gabbro, peridotite); c) the type of heat source (magmatic bodies at depth, hot lithosphere, serpentinization reactions); d) and the associated temperature of outflow fluids (high- vs.- low temperature venting and their relative proportion). A systematic review of the distribution and characteristics of hydrothermal fields along the slow-spreading Mid-Atlantic Ridge suggests that long-lived hydrothermal activity is concentrated either at oceanic detachment faults, or along volcanic segments with evidence of robust magma supply to the axis. A detailed study of the magmatically robust Lucky Strike segment suggests that all present and past hydrothermal activity is found at the center of the segment. The association of these fields to central volcanos, and the absence of indicators of hydrothermal activity along the remaining of the ridge segment, suggests that long-lived hydrothermal activity in these volcanic systems is maintained by the enhanced melt supply and the associated magma chamber(s) required to build these volcanic edifices. In this setting, hydrothermal outflow zones at the seafloor are systematically controlled by faults, indicating that hydrothermal fluids in the shallow crust exploit permeable fault zones to circulate. While

  8. Sensitivity of seafloor bathymetry to climate-driven fluctuations in mid-ocean ridge magma supply.

    Science.gov (United States)

    Olive, J-A; Behn, M D; Ito, G; Buck, W R; Escartín, J; Howell, S

    2015-10-16

    Recent studies have proposed that the bathymetric fabric of the seafloor formed at mid-ocean ridges records rapid (23,000 to 100,000 years) fluctuations in ridge magma supply caused by sealevel changes that modulate melt production in the underlying mantle. Using quantitative models of faulting and magma emplacement, we demonstrate that, in fact, seafloor-shaping processes act as a low-pass filter on variations in magma supply, strongly damping fluctuations shorter than about 100,000 years. We show that the systematic decrease in dominant seafloor wavelengths with increasing spreading rate is best explained by a model of fault growth and abandonment under a steady magma input. This provides a robust framework for deciphering the footprint of mantle melting in the fabric of abyssal hills, the most common topographic feature on Earth. Copyright © 2015, American Association for the Advancement of Science.

  9. The beach ridges of India: A review

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.; Wagle, B.G.

    , and is presented in a consolidated form. Beach ridges of the east and west coast of India are grouped in thirteen-beach ridge complexes based on their association. Review indicates that the beach ridges of India are not older than the Holocene age...

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

    International Nuclear Information System (INIS)

    Abdou, A A; Shaw, A; Mason, A; Al-Shamma'a, A; Cullen, J; Wylie, S; Diallo, M

    2013-01-01

    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.

  11. Sedentism, social change, warfare, and the bow in the ancient Pueblo Southwest.

    Science.gov (United States)

    Reed, Paul F; Geib, Phil R

    2013-01-01

    In the ancient American Southwest, use of the bow developed relatively rapidly among Pueblo people by the fifth century AD. This new technology replaced the millennia-old atlatl and dart weaponry system. Roughly 150 years later in the AD 600s, Pueblo socioeconomic organization began to evolve rapidly, as many groups adopted a much more sedentary life. Multiple factors converged to allow this sedentary pattern to emerge, but the role of the bow in this process has not been fully explored. In this paper, we trace the development of the bow and discuss its role as sedentism emerged and social changes occurred in ancient Puebloan society from the fifth through seventh centuries AD. Copyright © 2013 Wiley Periodicals, Inc.

  12. Reliability of the input admittance of bowed-string instruments measured by the hammer method.

    Science.gov (United States)

    Zhang, Ailin; Woodhouse, Jim

    2014-12-01

    The input admittance at the bridge, measured by hammer testing, is often regarded as the most useful and convenient measurement of the vibrational behavior of a bowed string instrument. However, this method has been questioned, due especially to differences between human bowing and hammer impact. The goal of the research presented here is to investigate the reliability and accuracy of this classic hammer method. Experimental studies were carried out on cellos, with three different driving conditions and three different boundary conditions. Results suggest that there is nothing fundamentally different about the hammer method, compared to other kinds of excitation. The third series of experiments offers an opportunity to explore the difference between the input admittance measuring from one bridge corner to another and that of single strings. The classic measurement is found to give a reasonable approximation to that of all four strings. Some possible differences between the hammer method and normal bowing and implications of the acoustical results are also discussed.

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

    International Nuclear Information System (INIS)

    Chen, Qiang; Chen, Bin; Yi, Yun; Chen, P. F.; Mao, Yunfei; Xiong, Run

    2015-01-01

    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

  14. An IRAS/ISSA Survey of Bow Shocks Around Runaway Stars

    Science.gov (United States)

    Buren, David Van

    1995-01-01

    We searched for bow shock-like objects like those known around Oph and a Cam near the positions of 183 runaway stars. Based primarily on the presence and morphology of excess 60 micron emission we identify 56 new candidate bow shocks, for which we determine photometric and morphological parameters. Previously only a dozen or so were known. Well resolved structures are present around 25 stars. A comparison of the distribution of symmetry axes of the infrared nebulae with that of their proper motion vectors indicates that these two directions are very significantly aligned. The observed alignment strongly suggests that the structures we see arise from the interaction of stellar winds with the interstellar medium, justifying the identification of these far-infrared objects as stellar wind bow shocks.

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

    International Nuclear Information System (INIS)

    Garel, Catherine; Dhouib, Amira; Sileo, Chiara; Ducou le Pointe, Hubert; Cormier-Daire, Valerie

    2014-01-01

    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.)

  16. 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.)

  17. Improved bow shock models for Herbig-Haro objects - application to HH 2A-prime

    International Nuclear Information System (INIS)

    Raymond, J.C.; Hartmann, L.; Hartigan, P.

    1988-01-01

    An improved version of the bow shock theory previously applied to Herbig-Haro objects is presented. The modifications provide a more accurate calculation of the ionization state of material entering the bow shock. The revised preionization does not drastically affect the emission-line predictions for a 200 km/s bow shock model, though the effects will be more severe for slower shock velocities. The line profiles of the new models resemble the observed profiles somewhat more closely, and the relative emission-line intensities typically differ by 30 percent from those predicted by the older models. The models agree well with new IUE spectra and existing optical data for HH 2A-prime. 32 references

  18. Liquefaction along Late Pleistocene to early Holocene Faults as Revealed by Lidar in Northwest Tasmania, Australia

    Science.gov (United States)

    Webb, J.; Gardner, T.

    2016-12-01

    In northwest Tasmania well-preserved mid-Holocene beach ridges with maximum radiocarbon ages of 5.25 ka occur along the coast; inland are a parallel set of lower relief beach ridges of probable MIS 5e age. The latter are cut by northeast-striking faults clearly visible on LIDAR images, with a maximum vertical displacement (evident as difference in topographic elevation) of 3 m. Also distinct on the LIDAR images are large sand boils along the fault lines; they are up to 5 m in diameter and 2-3 m high and mostly occur on the hanging wall close to the fault traces. Without LIDAR it would have been almost impossible to distinguish either the fault scarps or the sand boils. Excavations through the sand boils show that they are massive, with no internal structure, suggesting that they formed in a single event. They are composed of well-sorted, very fine white sand, identical to the sand in the underlying beach ridges. The sand boils overlie a peaty paleosol; this formed in the tea-tree swamp that formerly covered the area, and has been offset along the faults. Radiocarbon dating of the buried organic-rich paleosol gave ages of 14.8-7.2 ka, suggesting that the faulting is latest Pleistocene to early Holocene in age; it occurred prior to deposition of the mid-Holocene beach ridges, which are not offset. The beach ridge sediments are up to 7 m thick and contain an iron-cemented hard pan 1-3 m below the surface. The water table is very shallow and close to the ground surface, so the sands of the beach ridges are mostly saturated. During faulting these sands experienced extensive liquefaction. The resulting sand boils rose to a substantial height of 2-3 m, probably possibly reflecting the elevation of the potentiometric surface within the confined part of the beach ridge sediments below the iron-cemented hard pan. Motion on the faults was predominantly dip slip (shown by an absence of horizontal offset) and probably reverse, which is consistent with the present-day northwest

  19. Hydrothermal plume anomalies over the southwest Indian ridge: magmatic control

    Science.gov (United States)

    Yue, X.; Li, H.; Tao, C.; Ren, J.; Zhou, J.; Chen, J.; Chen, S.; Wang, Y.

    2017-12-01

    Here we firstly reported the extensive survey results of the hydrothermal activity along the ultra-slow spreading southwest Indian ridge (SWIR). The study area is located at segment 27, between the Indomed and Gallieni transform faults, SWIR. The seismic crustal thickness reaches 9.5km in this segment (Li et al., 2015), which is much thicker than normal crustal. The anomaly thickened crust could be affected by the Crozet hotspot or highly focused melt delivery from the mantle. The Duanqiao hydrothermal field was reported at the ridge valley of the segment by Tao et al (2009). The Deep-towed Hydrothermal Detection System (DHDS) was used to collect information related with hydrothermal activity, like temperature, turbidity, oxidation-reduction potential (ORP) and seabed types. There are 15 survey lines at the interval of 2 to 3 km which are occupied about 1300 km2 in segment 27. After processing the raw data, including wiping out random noise points, 5-points moving average processing and subtracting the ambient, we got anomalous Nephelometric Turbidity Units values (ΔNTU). And dE/dt was used to identify the ORP anomalous as the raw data is easily influenced by electrode potentials drifting (Baker et al., 2016). According to the results of water column turbidity and ORP distributions, we confirmed three hydrothermal anomaly fields named A1, A2 and A3. The three fields are all located in the western part of the segment. The A1 field lies on the ridge valley, west side of Duanqiao field. The A2 and A3 field lie on the northern and southern of the ridge valley, respectively. We propose that recent magmatic activity probably focus on the western part of segment 27.And the extensive distribution of hydrothermal plume in the segment is the result of the discrete magma intrusion. References Baker E T, et al. How many vent fields? New estimates of vent field populations on ocean ridges from precise mapping of hydrothermal discharge locations. EPSL, 2016, 449:186-196. Li J

  20. Magnetic field fluctuations across the Earth's bow shock

    Energy Technology Data Exchange (ETDEWEB)

    Czaykowska, A.; Bauer, T.M. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany); Treumann, R.A. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany); Centre for Interdisciplinary Plasma Science, Garching (Germany); International Space Science Inst. (ISSI), Bern (Switzerland); Baumjohann, W. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany); Inst. fuer Weltraumforschung der Oesterreichischen Akademie der Wissenschaften, Graz (Austria)

    2001-03-01

    We present a statistical analysis of 132 dayside (LT 0700-1700) bow shock crossings of the AMPTE/IRM spacecraft. We perform a superposed epoch analysis of low frequency, magnetic power spectra some minutes upstream and downstream of the bow shock. The events are devided into categories depending on the angle {theta}{sub Bn} between bow shock normal and interplanetary magnetic field, and on plasma-{beta}. In the foreshock upstream of the quasi-parallel bow shock, the power of the magnetic fluctuations is roughly 1 order of magnitude larger ({delta}B {proportional_to} 4 nT for frequencies 0.01-0.04 Hz) than upstream of the quasi-perpendicular shock. There is no significant difference in the magnetic power spectra upstream and downstream of the quasi-parallel bow shock; only at the shock itself, is the magnetic power enhanced by a factor of 4. This enhancement may be due to either an amplification of convecting upstream waves or to wave generation at the shock interface. On the contrary, downstream of the quasi-perpendicular shock, the magnetic wave activity is considerably higher than upstream. Downstream of the quasi-perpendicular low-{beta} bow shock, we find a dominance of the left-hand polarized component at frequencies just below the ion-cyclotron frequency, with amplitudes of about 3 nT. These waves are identified as ion-cyclotron waves, which grow in a low-{beta} regime due to the proton temperature anisotropy. We find a strong correlation of this anisotropy with the intensity of the left-hand polarized component. Downstream of some nearly perpendicular ({theta}{sub Bn} {approx} 90 ) high-{beta} crossings, mirror waves are identified. However, there are also cases where the conditions for mirror modes are met downstream of the nearly perpendicular shock, but no mirror waves are observed. (orig.)

  1. NUMERICAL SIMULATION OF THE SVS 13 MICROJET AND BOW SHOCK BUBBLE

    International Nuclear Information System (INIS)

    Gardner, Carl L.; Jones, Jeremiah R.; Hodapp, Klaus W.

    2016-01-01

    Numerical simulations of the SVS 13 microjet and bow shock bubble are performed using the WENO method that reproduces the main features and dynamics of data from the Keck Telescope/OSIRIS velocity-resolved integral field spectrograph: an expanding, cooler bow shock bubble, with the bubble center moving at approximately 50 km s −1 with a radial expansion velocity of 11 km s −1 , surrounding the fast, hotter jet, which is propagating at 156 km s −1 . Contact and bow shock waves are visible in the simulations both from the initial short jet pulse that creates the nearly spherical bow shock bubble and from the fast microjet, while a terminal Mach disk shock is visible near the tip of the continuous microjet, which reduces the velocity of the jet gas down to the flow velocity of the contact discontinuity at the leading edge of the jet. At 21.1 years after the launch of the initial bubble pulse, the jet has caught up with and penetrated almost all the way across the bow shock bubble of the slower initial pulse. At times later than about 22 years, the jet has penetrated through the bubble and thereafter begins to subsume its spherical form. Emission maps from the simulations of the jet—traced by the emission of the shock-excited 1.644 μ m [Fe ii] line—and the bow shock bubble—traced in the lower excitation 2.122 μ m H 2 1–0 S(1) line—projected onto the plane of the sky are presented, and are in good agreement with the Keck observations.

  2. Numerical Simulation of the SVS 13 Microjet and Bow Shock Bubble

    Science.gov (United States)

    Gardner, Carl L.; Jones, Jeremiah R.; Hodapp, Klaus W.

    2016-10-01

    Numerical simulations of the SVS 13 microjet and bow shock bubble are performed using the WENO method that reproduces the main features and dynamics of data from the Keck Telescope/OSIRIS velocity-resolved integral field spectrograph: an expanding, cooler bow shock bubble, with the bubble center moving at approximately 50 km s-1 with a radial expansion velocity of 11 km s-1, surrounding the fast, hotter jet, which is propagating at 156 km s-1. Contact and bow shock waves are visible in the simulations both from the initial short jet pulse that creates the nearly spherical bow shock bubble and from the fast microjet, while a terminal Mach disk shock is visible near the tip of the continuous microjet, which reduces the velocity of the jet gas down to the flow velocity of the contact discontinuity at the leading edge of the jet. At 21.1 years after the launch of the initial bubble pulse, the jet has caught up with and penetrated almost all the way across the bow shock bubble of the slower initial pulse. At times later than about 22 years, the jet has penetrated through the bubble and thereafter begins to subsume its spherical form. Emission maps from the simulations of the jet—traced by the emission of the shock-excited 1.644 μm [Fe II] line—and the bow shock bubble—traced in the lower excitation 2.122 μm H2 1-0 S(1) line—projected onto the plane of the sky are presented, and are in good agreement with the Keck observations.

  3. 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.

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

    Science.gov (United States)

    Nazir, Nazia; Sujesh, M; Kumar, Ravi; Sreenivas, P

    2012-01-01

    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. 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. 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 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. 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.

  5. Active spreading processes at ultraslow mid-ocean ridges: The 1999-2001 seismo-volcanic episode at 85°E Gakkel ridge, Arctic Ocean

    Science.gov (United States)

    Schlindwein, Vera; Riedel, Carsten; Korger, Edith; Läderach, Christine

    2010-05-01

    seismicity migration, the swarm activated the rift valley boundary faults in a large area. Along the entire Gakkel ridge, normal fault earthquakes occur predominantly at volcanic centres pointing to strong tectonomagmatic interplay. - unusual change in swarm characteristics: Following 2-3 months of predominantly tectonic faulting, the swarm displays increasing non-double couple character events and an abrupt change in event rate preceded by three conspicuous events of high similarity located in the vicinity of potentially active volcanic structures. Brittle faulting may thus trigger later volcanic discharge or it could be in turn triggered by rising melts. - unusual volcanic discharge: In 2007, Sohn et al. (2008) discovered abundant pyroclastic deposits containing limu o Pele at the 85°E volcanic complex and therefore postulated recent deep submarine explosive volcanism at this site. In order to drive these explosive eruptions at 4 km water depth, high volume fractions of magmatic volatiles must be accumulated locally, for example at the top of a magma chamber under a thick and stable lithospheric roof. Together with the Strombolian eruptions which we inferred from the seismoacoustic explosion signals recorded in 2001, this indicates that an explosive eruption style may be common for volcanic spreading events at ultraslow spreading ridges. Sohn et al. (2008), Explosive volcanism on the ultraslow-spreading Gakkel Ridge, Arctic Ocean, Nature, 453,doi:10.1038/nature07075.

  6. Model-based monitoring of rotors with multiple coexisting faults

    International Nuclear Information System (INIS)

    Rossner, Markus

    2015-01-01

    Monitoring systems are applied to many rotors, but only few monitoring systems can separate coexisting errors and identify their quantity. This research project solves this problem using a combination of signal-based and model-based monitoring. The signal-based part performs a pre-selection of possible errors; these errors are further separated with model-based methods. This approach is demonstrated for the errors unbalance, bow, stator-fixed misalignment, rotor-fixed misalignment and roundness errors. For the model-based part, unambiguous error definitions and models are set up. The Ritz approach reduces the model order and therefore speeds up the diagnosis. Identification algorithms are developed for the different rotor faults. Hereto, reliable damage indicators and proper sub steps of the diagnosis have to be defined. For several monitoring problems, measuring both deflection and bearing force is very useful. The monitoring system is verified by experiments on an academic rotor test rig. The interpretation of the measurements requires much knowledge concerning the dynamics of the rotor. Due to the model-based approach, the system can separate errors with similar signal patterns and identify bow and roundness error online at operation speed. [de

  7. 76 FR 2710 - Pitney Bowes, Inc., Mailing Solutions Management Division Including On-Site Leased Workers of...

    Science.gov (United States)

    2011-01-14

    ...., Mailing Solutions Management Division Including On-Site Leased Workers of Guidant Group, and Teleworkers... Bowes, Inc., Mailing Solutions Management Division, Engineering Quality Assurance, Shelton, Connecticut... identity of the subject worker group. The worker group consists of workers of Pitney Bowes, Inc., the...

  8. Gondwana subduction-modified mantle domain prevents magmatic seafloor generation in the Central Indian Ridge

    Science.gov (United States)

    Morishita, T.; Nakamura, K.; Senda, R.; Suzuki, K.; Kumagai, H.; Sato, H.; Sato, T.; Shibuya, T.; Minoguchi, K.; Okino, K.

    2013-12-01

    The creation of oceanic crust at mid-ocean ridges is essential to understanding the genesis of oceanic plate and the evolution of the Earth. Detailed bathymetric measurements coupled with dense sample recovery at mid-ocean ridge revealed a wide range of variations in the ridge and seafloor morphologies, which cannot be simply explained by a spreading rate, but also by ridge geometry, mantle compositions and thermal structure (Dick et al., 2003 Nature; Cannat et al. 2006 Geology). It is now widely accepted that very limited magmatic activity with tectonic stretching generates oceanic core complex and/or smooth seafloor surface in the slow to ultraslow-spreading ridges, where serpentinized peridotite and gabbros are expected to be exposed associated with detachment faults (Cann et al., 1997 Nature; Cannat et al., 2006), although magmatism might be an essential role for the formation of oceanic core complexes (Buck et al., 2005 Nature; Tucholke et al 2008 JGR). A rising question is why magmatic activity is sometimes prevented during the oceanic plate formation. Ancient melting domain, that are too refractory to melt even in adiabatically upwelling to the shallow upper mantle, might cause the amagmatic spreading ridges (Harvey et al., 2006 EPSL, Liu et al.,2008 Nature). Its origin and effect on seafloor generations are, however, not well understood yet. We report an oceanic hill as an example of an ancient subduction-modified mantle domain, probably formed at continental margin of the Gondwanaland~Pangea supercontinent, existing beneath the Central Indian Ridge. This domain is the most likely to have prevented magmatic seafloor generation, resulting in creation of very deep oceanic valley and serpentine diaper (now the studied oceanic hill) at the present Central Indian ridge.

  9. Wrist muscle activity of khatrah approach in Mameluke technique using traditional bow archery

    Science.gov (United States)

    Ariffin, Muhammad Shahimi; Rambely, Azmin Sham; Ariff, Noratiqah Mohd

    2018-04-01

    An investigation of khatrah technique in archery was carried out. An electromyography (EMG) experiment was conducted towards six wrist muscles which are flexor carpi radialis, extensor carpi ulnaris and extensor digitorum communis for both arms. The maximum voluntary contraction (MVC) and activity data were recorded. The bow arm produced a higher muscle force compared to draw arm muscles during release phase. However, the muscle forces produced by bow arm had a consistency in term of pattern throughout the phases. In conclusion, the forces generated by the professional archer produced a force benchmark at the wrist joint to alleviate the risk of injury.

  10. ASYMPTOTIC STEADY-STATE SOLUTION TO A BOW SHOCK WITH AN INFINITE MACH NUMBER

    Energy Technology Data Exchange (ETDEWEB)

    Yalinewich, Almog; Sari, Re’em [Racah Institute of Physics, the Hebrew University, 91904, Jerusalem (Israel)

    2016-08-01

    The problem of a cold gas flowing past a stationary obstacle is considered. We study the bow shock that forms around the obstacle and show that at large distances from the obstacle the shock front forms a parabolic solid of revolution. The profiles of the hydrodynamic variables in the interior of the shock are obtained by solution of the hydrodynamic equations in parabolic coordinates. The results are verified with a hydrodynamic simulation. The drag force on the obstacle is also calculated. Finally, we use these results to model the bow shock around an isolated neutron star.

  11. Bathymetric Signatures of Oceanic Detachment Faulting and Potential Ultramafic Lithologies at Outcrop or in the Shallow Subseafloor

    Science.gov (United States)

    Cann, J. R.; Smith, D. K.; Escartin, J.; Schouten, H.

    2008-12-01

    For ten years, domal bathymetric features capped by corrugated and striated surfaces have been recognized as exposures of oceanic detachment faults, and hence potentially as exposures of plutonic rocks from lower crust or upper mantle. Associated with these domes are other bathymetric features that indicate the presence of detachment faulting. Taken together these bathymetric signatures allow the mapping of large areas of detachment faulting at slow and intermediate spreading ridges, both at the axis and away from it. These features are: 1. Smooth elevated domes corrugated parallel to the spreading direction, typically 10-30 km wide parallel to the axis; 2. Linear ridges with outward-facing slopes steeper than 20°, running parallel to the spreading axis, typically 10-30 km long; 3. Deep basins with steep sides and relatively flat floors, typically 10-20 km long parallel to the spreading axis and 5-10 km wide. This characteristic bathymetric association arises from the rolling over of long-lived detachment faults as they spread away from the axis. The faults dip steeply close to their origin at a few kilometers depth near the spreading axis, and rotate to shallow dips as they continue to evolve, with associated footwall flexure and rotation of rider blocks carried on the fault surface. The outward slopes of the linear ridges can be shown to be rotated volcanic seafloor transported from the median valley floor. The basins may be formed by the footwall flexure, and may be exposures of the detachment surface. Critical in this analysis is that the corrugated domes are not the only sites of detachment faulting, but are the places where higher parts of much more extensive detachment faults happen to be exposed. The fault plane rises and falls along axis, and in some places is covered by rider blocks, while in others it is exposed at the sea floor. We use this association to search for evidence for detachment faulting in existing surveys, identifying for example an area

  12. Width of surface rupture zone for thrust earthquakes: implications for earthquake fault zoning

    Science.gov (United States)

    Boncio, Paolo; Liberi, Francesca; Caldarella, Martina; Nurminen, Fiia-Charlotta

    2018-01-01

    The criteria for zoning the surface fault rupture hazard (SFRH) along thrust faults are defined by analysing the characteristics of the areas of coseismic surface faulting in thrust earthquakes. Normal and strike-slip faults have been deeply studied by other authors concerning the SFRH, while thrust faults have not been studied with comparable attention. Surface faulting data were compiled for 11 well-studied historic thrust earthquakes occurred globally (5.4 ≤ M ≤ 7.9). Several different types of coseismic fault scarps characterize the analysed earthquakes, depending on the topography, fault geometry and near-surface materials (simple and hanging wall collapse scarps, pressure ridges, fold scarps and thrust or pressure ridges with bending-moment or flexural-slip fault ruptures due to large-scale folding). For all the earthquakes, the distance of distributed ruptures from the principal fault rupture (r) and the width of the rupture zone (WRZ) were compiled directly from the literature or measured systematically in GIS-georeferenced published maps. Overall, surface ruptures can occur up to large distances from the main fault ( ˜ 2150 m on the footwall and ˜ 3100 m on the hanging wall). Most of the ruptures occur on the hanging wall, preferentially in the vicinity of the principal fault trace ( > ˜ 50 % at distances guidelines). In the absence of such a very detailed study (basic SM, i.e. Level 1 SM of Italian guidelines) a width of ˜ 840 m (90 % probability from "simple thrust" database of distributed ruptures, excluding B-M, F-S and Sy fault ruptures) is suggested to be sufficiently precautionary. For more detailed SM, where the fault is carefully mapped, one must consider that the highest SFRH is concentrated in a narrow zone, ˜ 60 m in width, that should be considered as a fault avoidance zone (more than one-third of the distributed ruptures are expected to occur within this zone). The fault rupture hazard zones should be asymmetric compared to the trace

  13. Seismic-reflection surveys of the Blake Ridge, R/V Cape Hatteras, 1992 and 1995; data acquisition, navigation and processing

    Science.gov (United States)

    Taylor, Michael H.; Dillon, William P.; Anton, Christopher H.; Danforth, William W.

    1999-01-01

    As part of an ongoing study, seismic-reflection profiles were collected over the Blake Ridge in 1992 and 1995, in order to map the volume and distribution of methane hydrate. Faulting and seafloor instabilities appear to be related to methane hydrate processes at the Blake Ridge. Seismic profiles display a prominent collapse structure at the crest, which is inferred to have resulted from the mobilization of sediment that was associated with methane hydrate dissociation.

  14. Structure and Dynamics of the Southeast Indian Ridge, 129°E to 140°E, and Off-axis Volcanism: Preliminary Results of the STORM Cruise

    Science.gov (United States)

    Briais, Anne; Barrère, Fabienne; Boulart, Cédric; Ceuleneer, Georges; Ferreira, Nicolas; Hanan, Barry; Hémond, Christophe; Macleod, Sarah; Maia, Marcia; Maillard, Agnès; Merkuryev, Sergey; Park, Sung-Hyun; Révillon, Sidonie; Ruellan, Etienne; Schohn, Alexandre; Watson, Sally; Yang, Yun-Seok

    2016-04-01

    We present observations of the South-East Indian Ridge (SEIR) collected during the STORM cruise (South Tasmania Ocean Ridge and Mantle) on the N/O L'Atalante early 2015. The SEIR between Australia and Antarctica displays large variations of axial morphology despite an almost constant intermediate spreading rate. The Australia-Antarctic Discordance (AAD) between 120°E and 128°E is a section of the mid-ocean ridge where the magma budget is abnormally low, and which marks the boundary between Indian and Pacific mantle domains with distinct geochemical isotopic compositions. The STORM project focuses on the area east of the discordance from 128 to 140°E, where gravity highs observed on satellite-derived maps of the flanks of the SEIR reveal numerous volcanic seamounts. A major objective of the STORM cruise was to test the hypothesis of a mantle flow from the Pacific to the Indian domains. We collected multibeam bathymetry and magnetic data between 136 and 138°E to map off-axis volcanic ridges up to 10 Ma-old crust. We mapped the SEIR axis between 129 and 140°E, and the northern part of the George V transform fault. We collected rock samples on seamounts and in the transform fault, basaltic glass samples along the ridge axis, and near-bottom samples and in-situ measurements in the water column. Our observations reveal that the off-axis seamounts form near the SEIR axis, are not associated to off-axis deformation of the ocean floor, and are often located near the traces of ridge axis discontinuities. We also observe a general shallowing of the ridge axis from the AAD to the George V TF and the presence of robust axial segments near the transform fault. Our new data allow us to describe the complex evolution of the transform fault system. They also permit to locate new hydrothermal systems along the ridge axis.

  15. Closure of the Africa-Eurasia-North America plate motion circuit and tectonics of the Gloria fault

    Science.gov (United States)

    Argus, Donald F.; Gordon, Richard G.; Demets, Charles; Stein, Seth

    1989-01-01

    The current motions of the African, Eurasian, and North American plates are examined. The problems addressed include whether there is resolvable motion of a Spitsbergen microplate, the direction of motion between the African and North American plates, whether the Gloria fault is an active transform fault, and the implications of plate circuit closures for rates of intraplate deformation. Marine geophysical data and magnetic profiles are used to construct a model which predicts about 4 mm/yr slip across the Azores-Gibraltar Ridge, and west-northwest convergence near Gibraltar. The analyzed data are consistent with a rigid plate model with the Gloria fault being a transform fault.

  16. Seismic reflection profile of the Blake Ridge near sites 994, 995, and 997: Chapter 4

    Science.gov (United States)

    Dillon, William P.; Hutchinson, Deborah R.; Drury, Rebecca M.

    1996-01-01

    Seismic reflection profiles near Sites 994, 995, and 997 were collected with seismic sources that provide maximum resolution with adequate power to image the zone of gas hydrate stability and the region direction beneath it. The overall structure of the sediment drift deposit that constitutes the Blake Ridge consists of southwestward-dipping strata. These strata are approximately conformal to the seafloor on the southwest side of the ridge and are truncated by erosion on the northeast side. A bottom-simulating reflection (BSR) marks the velocity contrast between gas hydrate-bearing sediment and regions containing free gas beneath the zone of gas hydrate stability. The BSR is strong and continuous near the ridge crest but becomes discontinuous on the flanks, where concentration of gas is reduced and dipping strata pass through the level of the base o fgas hydrate stability or the strata are disrupted by faults. Seismic reflection amplitudes appear to be reduced in the region of gas hydrate formation compared to normal amplitudes. A faulted zone ~0.5-0.6 s thick parallels reflections from strata. We infer that this may represent a formerly gas hydrate-bearing zone that was faulted because of a breakdown of hydrate near its phase limit (at the base of the zone). Strong reflections at the top of the faulted zone are caused by free-gas acccumulation at Site 994. Similar strong reflections probably are caused by free-gas accumulations where the top of the faulted zone rises above the BSR, although this would require local free gas within the hydrate-stable zone.

  17. Fault tree graphics

    International Nuclear Information System (INIS)

    Bass, L.; Wynholds, H.W.; Porterfield, W.R.

    1975-01-01

    Described is an operational system that enables the user, through an intelligent graphics terminal, to construct, modify, analyze, and store fault trees. With this system, complex engineering designs can be analyzed. This paper discusses the system and its capabilities. Included is a brief discussion of fault tree analysis, which represents an aspect of reliability and safety modeling

  18. Bose enhancement and the ridge

    Energy Technology Data Exchange (ETDEWEB)

    Altinoluk, Tolga [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain); Armesto, Néstor, E-mail: nestor.armesto@usc.es [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain); Beuf, Guillaume [Department of Physics, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel); Kovner, Alex [Physics Department, University of Connecticut, 2152 Hillside Road, Storrs, CT 06269-3046 (United States); Lublinsky, Michael [Department of Physics, Ben-Gurion University of the Negev, Beer Sheva 84105 (Israel)

    2015-12-17

    We point out that Bose enhancement in a hadronic wave function generically leads to correlations between produced particles. We show explicitly, by calculating the projectile density matrix in the Color Glass Condensate approach to high-energy hadronic collisions, that the Bose enhancement of gluons in the projectile leads to azimuthal collimation of long range rapidity correlations of the produced particles, the so-called ridge correlations.

  19. Bose enhancement and the ridge

    Directory of Open Access Journals (Sweden)

    Tolga Altinoluk

    2015-12-01

    Full Text Available We point out that Bose enhancement in a hadronic wave function generically leads to correlations between produced particles. We show explicitly, by calculating the projectile density matrix in the Color Glass Condensate approach to high-energy hadronic collisions, that the Bose enhancement of gluons in the projectile leads to azimuthal collimation of long range rapidity correlations of the produced particles, the so-called ridge correlations.

  20. Oak Ridge National Laboratory Review

    Energy Technology Data Exchange (ETDEWEB)

    Krause, C.; Pearce, J.; Zucker, A. (eds.)

    1992-01-01

    This report presents brief descriptions of the following programs at Oak Ridge National Laboratory: The effects of pollution and climate change on forests; automation to improve the safety and efficiency of rearming battle tanks; new technologies for DNA sequencing; ORNL probes the human genome; ORNL as a supercomputer research center; paving the way to superconcrete made with polystyrene; a new look at supercritical water used in waste treatment; and small mammals as environmental monitors.

  1. Factors for simultaneous rupture assessment of active fault. Part 1. Fault geometry and slip-distribution based on tectonic geomorphological and paleoseismological investigations

    International Nuclear Information System (INIS)

    Sasaki, Toshinori; Ueta, Keiichi

    2012-01-01

    It is important to evaluate the magnitude of an earthquake caused by multiple active faults, taking into account the simultaneous effects. The simultaneity of adjacent active faults is often decided on the basis of geometric distances except for the cases in which paleoseismic records of these faults are well known. We have been studying the step area between the Nukumi fault and the Neodani fault, which appeared as consecutive ruptures in the 1891 Nobi earthquake, since 2009. The purpose of this study is to establish innovation in valuation technique of the simultaneity of adjacent active faults in addition to the techniques based on the paleoseismic record and the geometric distance. The present work is intended to clarify the distribution of tectonic geomorphology along the Nukumi fault and the Neodani fault by high-resolution interpretations of airborne LiDAR DEM and aerial photograph, and the field survey of outcrops and location survey. As a result of topographic survey, we found consecutive tectonic topography which is left lateral displacement of ridge and valley lines and reverse scarplets along these faults in dense vegetation area. We have found several new outcrops in this area where the surface ruptures of the 1891 Nobi earthquake have not been known. At the several outcrops, humic layer whose age is from 14th century to 19th century by 14C age dating was deformed by the active fault. We conclude that the surface rupture of Nukumi fault in the 1891 Nobi earthquake is continuous to 12km southeast of Nukumi village. In other words, these findings indicate that there is 10-12km parallel overlap zone between the surface rupture of the southeastern end of Nukumi fault and the northwestern end of Neodani fault. (author)

  2. How do normal faults grow?

    OpenAIRE

    Blækkan, Ingvild; Bell, Rebecca; Rotevatn, Atle; Jackson, Christopher; Tvedt, Anette

    2018-01-01

    Faults grow via a sympathetic increase in their displacement and length (isolated fault model), or by rapid length establishment and subsequent displacement accrual (constant-length fault model). To test the significance and applicability of these two models, we use time-series displacement (D) and length (L) data extracted for faults from nature and experiments. We document a range of fault behaviours, from sympathetic D-L fault growth (isolated growth) to sub-vertical D-L growth trajectorie...

  3. Characterization of leaky faults

    International Nuclear Information System (INIS)

    Shan, Chao.

    1990-05-01

    Leaky faults provide a flow path for fluids to move underground. It is very important to characterize such faults in various engineering projects. The purpose of this work is to develop mathematical solutions for this characterization. The flow of water in an aquifer system and the flow of air in the unsaturated fault-rock system were studied. If the leaky fault cuts through two aquifers, characterization of the fault can be achieved by pumping water from one of the aquifers, which are assumed to be horizontal and of uniform thickness. Analytical solutions have been developed for two cases of either a negligibly small or a significantly large drawdown in the unpumped aquifer. Some practical methods for using these solutions are presented. 45 refs., 72 figs., 11 tabs

  4. Solar system fault detection

    Science.gov (United States)

    Farrington, R.B.; Pruett, J.C. Jr.

    1984-05-14

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  5. Seismic Slip on an Oblique Detachment Fault at Low Angles

    Science.gov (United States)

    Janecke, S. U.; Steely, A. N.; Evans, J. P.

    2008-12-01

    Pseudotachylytes are one of the few accepted indicators of seismic slip along ancient faults. Low-angle normal faults have produced few large earthquakes in historic times and low-angle normal faults (detachment faults) are typically severely misoriented relative to a vertical maximum compressive stress. As a result many geoscientists question whether low-angle normal faults produce earthquakes at low angles. Relationships in southern California show that a major low-angle normal-oblique fault slipped at low angles and produced large earthquakes. The exhumed Late Cenozoic West Salton detachment fault preserves spectacular fault- related pseudotachylytes along its fault plane and injected into its hanging wall and footwall. Composite pseudotachylyte zones are up to 1.25 m thick and persists over lateral distances of at least 10's of meters. Pseudotachylyte is common in most thin sections of damaged fault rocks with more than 20% (by volume) of cataclasite. We recognized the presence of original melt using numerous criteria: abundant spherulites in thin sections, injection structures at both the thin-section and outcrop scale, black aphanitic textures, quenched vein margins, variations in microcrystallite textures and/or size with respect to the vein margin, and glassy textures in hand sample. Multiple earthquakes are inferred to produce the layered "stratigraphy" in some exposures of pseudotachylytes. We infer that the West Salton detachment fault formed and slipped at low angles because it nearly perfectly reactivates a Cretaceous ductile thrust system at the half km scale and dips between 10 and 45 degrees. The about 30 degree NNE dip of the detachment fault on the north side of Yaqui Ridge is likely steeper than its dip during detachment slip because there is local steepening on the flanks of the Yaqui Ridge antiform in a contractional stepover of a crosscutting Quaternary San Felipe dextral fault zone. These relationships indicate a low dip on the detachment

  6. Deformation, Fluid Flow and Mantle Serpentinization at Oceanic Transform Faults

    Science.gov (United States)

    Rupke, L.; Hasenclever, J.

    2017-12-01

    Oceanic transform faults (OTF) and fracture zones have long been hypothesized to be sites of enhanced fluid flow and biogeochemical exchange. In this context, the serpentine forming interaction between seawater and cold lithospheric mantle rocks is particularly interesting. The transformation of peridotite to serpentinite not only leads to hydration of oceanic plates and is thereby an important agent of the geological water cycle, it is also a mechanism of abiotic hydrogen and methane formation, which can support archeal and bacterial communities at the seafloor. Inferring the likely amount of mantle undergoing serpentinization reactions therefore allows estimating the amount of biomass that may be autotrophically produced at and around oceanic transform faults and mid-ocean ridges Here we present results of 3-D geodynamic model simulations that explore the interrelations between deformation, fluid flow, and mantle serpentinization at oceanic transform faults. We investigate how slip rate and fault offset affect the predicted patterns of mantle serpentinization around oceanic transform faults. Global rates of mantle serpentinization and associated H2 production are calculated by integrating the modeling results with plate boundary data. The global additional OTF-related production of H2 is found to be between 6.1 and 10.7 x 1011 mol per year, which is comparable to the predicted background mid-ocean ridge rate of 4.1 - 15.0 x 1011 mol H2/yr. This points to oceanic transform faults as potential sites of intense fluid-rock interaction, where chemosynthetic life could be sustained by serpentinization reactions.

  7. Reconsidering the process for bow-stave removal from juniper trees in the Great Basin

    Science.gov (United States)

    Constance I. Millar; Kevin T. Smith

    2017-01-01

    We question the growth arrestment hypothesis for bow stave removal used by indigenous people in the western Great Basin. Using modern understanding of tree growth and wound response, we suggest that growth would not be arrested by one or two transverse notches along a juniper stem. Rather these would trigger compartmentalization, which limits cambial death to within 10...

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

    International Nuclear Information System (INIS)

    Miki, K.

    1979-01-01

    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 60 0 with one another. BEACON is applied to the 60 0 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.)

  9. 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 § 48.4161(b)-1...

  10. Computing the Dust Distribution in the Bow Shock of a Fast-moving, Evolved Star

    NARCIS (Netherlands)

    van Marle, A. -J; Meliani, Z.; Keppens, R.; Decin, L.

    2011-01-01

    We study the hydrodynamical behavior occurring in the turbulent interaction zone of a fast-moving red supergiant star, where the circumstellar and interstellar material collide. In this wind–interstellar-medium collision, the familiar bow shock, contact discontinuity, and wind termination shock

  11. The role of the umrhubhe bow as transmitter of cultural knowledge ...

    African Journals Online (AJOL)

    The focus is also on Madosini's responses to several questions regarding her method of playing umrhubhe, with a view to understanding the indigenous use of technical language in its description of the process of producing musical sound on an unbraced,4 mouth-resonated bow. Journal of Musical Arts in Africa Vol.

  12. Historic range of variability for upland vegetation in the Medicine Bow National Forest, Wyoming

    Science.gov (United States)

    Gregory K. Dillon; Dennis H. Knight; Carolyn B. Meyer

    2005-01-01

    An approach for synthesizing the results of ecological research pertinent to land management is the analysis of the historic range of variability (HRV) for key ecosystem variables that are affected by management activities. This report provides an HRV analysis for the upland vegetation of the Medicine Bow National Forest in southeastern Wyoming. The variables include...

  13. Photo series for quantifying forest residues in managed lands of the Medicine Bow National Forest

    Science.gov (United States)

    John B. Popp; John E. Lundquist

    2006-01-01

    This photo series presents a visual representation of a range of fuel loading conditions specifically found on the Medicine Bow National Forest. The photos are grouped by forest type and past management practices. This field guide describes the distribution of different types of woody fuels and includes some vegetation data.

  14. Transient bowing of core assemblies in advanced liquid metal fast reactors

    International Nuclear Information System (INIS)

    Kamal, S.A.; Orechwa, Y.

    1986-01-01

    Two alternative core restraint concepts are considered for a conceptual design of a 900 MWth liquid metal fast reactor core with a heterogeneous layout. The two concepts, known as limited free bowing and free flowering, are evaluated based on core bowing criteria that emphasize the enhancement of inherent reactor safety. The core reactivity change during a postulated loss of flow transient is calculated in terms of the lateral displacements and displacement-reactivity-worths of the individual assemblies. The NUBOW-3D computer code is utilized to determine the assembly deformations and interassembly forces that arise when the assemblies are subjected to temperature gradients and irradiation induced creep and swelling during the reactor operation. The assembly ducts are made of the ferritic steel HT-9 and remain in the reactor core for four-years at full power condition. Whereas both restraint systems meet the bowing criteria, a properly designed limited free bowing system appears to be more advantageous than a free flowering system from the point of view of enhancing the reactor inherent safety

  15. Modelling of bow-tie microstrip antennas using modified locally conformal FDTD method

    NARCIS (Netherlands)

    George, J.

    2000-01-01

    An analysis of bow-tie microstrip antennas is presented based on the use of the modified locally conformal finite-difference time-domain (FDTD) method. This approach enables the number of cells along the antenna length and width to be chosen independently of the antenna central width, which helps to

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

    International Nuclear Information System (INIS)

    Alfonso Pallares, C; Perez Reyes, Y.; Sarabia Molina, I.I.

    2013-01-01

    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

  17. Calculation modelling of the RCCA movement through bowed FA guide tubes

    International Nuclear Information System (INIS)

    Razoumovsky, D.V.; Lihkachev, Yu.I.; Troyanov, V.M.

    2000-01-01

    Rod control cluster assembly movement through the bowed guide tubes is considered. The movement equation is presented with some of the assumptions and special attention is paid to the determination of the mechanical friction force. The numerical algorithm is described and some results of parametric studies are presented. (author)

  18. 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...

  19. Time-dependent bow shocks and the condensation structure of Herbig-Haro objects

    International Nuclear Information System (INIS)

    Raga, A.C.; Bohm, K.H.

    1987-01-01

    Some Herbig-Haro objects show a structure which appears to look like a bow shock, but also show a number of condensations superposed on this bow-shaped structure. In the case of HH 1 and HH 2 considerably different proper motions have been measured for the individual condensations. It is, however, very hard to explain why the condensations remain so close to each other if they are indeed separate entities. In this paper it is shown that an interpretation of the whole Herbig-Haro object as a single, time-dependent bow shock provides a natural explanation for the occurrence of condensations (which in numerical calculations appear to be associated with thermal instabilities in the postshock flow) with different proper motions. To this effect, time-dependent, axisymmetric, nonadiabatic bow shock models have been developed from which predictions were obtained for spatially resolved H-alpha intensity maps, and then these predictions are compared qualitatively with observations of a few Herbig-Haro objects. 57 references

  20. Modification of the ANC Nodal Code for analysis of PWR assembly bow

    International Nuclear Information System (INIS)

    Franceschini, Fausto; Fetterman, Robert J.; Little, David C.

    2008-01-01

    Refueling operations at certain PWR cores have revealed fuel assemblies with assembly bow that was higher than expected. As the fuel assemblies bow, the gaps between assemblies change from the uniform nominal configuration. This causes a change in the water volume which affects neutron moderation and thereby power distribution, fuel depletion history, rod internal pressure, etc., with non-trivial impacts on the safety analysis. Westinghouse has developed a new methodology for incorporation of assembly bow in its reload safety analysis package. As part of the new process, the standard Westinghouse reactor physics tool for core analysis, the Advanced Nodal Code ANC, has been modified. The modified ANC, ANCGAP, enables explicit treatment of three-dimensional gap distributions in its neutronic calculations; its accuracy is similar to that of the standard ANC, as demonstrated through an extensive benchmark campaign conducted over a variety of fuel compositions and challenging gap configurations. These features make ANCGAP a crucial tool in the Westinghouse assembly bow package. (authors)

  1. Modification of the ANC Nodal Code for analysis of PWR assembly bow

    Energy Technology Data Exchange (ETDEWEB)

    Franceschini, Fausto; Fetterman, Robert J.; Little, David C. [Westinghouse Electric Company LLC, Pittsburgh PA (United States)

    2008-07-01

    Refueling operations at certain PWR cores have revealed fuel assemblies with assembly bow that was higher than expected. As the fuel assemblies bow, the gaps between assemblies change from the uniform nominal configuration. This causes a change in the water volume which affects neutron moderation and thereby power distribution, fuel depletion history, rod internal pressure, etc., with non-trivial impacts on the safety analysis. Westinghouse has developed a new methodology for incorporation of assembly bow in its reload safety analysis package. As part of the new process, the standard Westinghouse reactor physics tool for core analysis, the Advanced Nodal Code ANC, has been modified. The modified ANC, ANCGAP, enables explicit treatment of three-dimensional gap distributions in its neutronic calculations; its accuracy is similar to that of the standard ANC, as demonstrated through an extensive benchmark campaign conducted over a variety of fuel compositions and challenging gap configurations. These features make ANCGAP a crucial tool in the Westinghouse assembly bow package. (authors)

  2. Variational Ridging in Sea Ice Models

    Science.gov (United States)

    Roberts, A.; Hunke, E. C.; Lipscomb, W. H.; Maslowski, W.; Kamal, S.

    2017-12-01

    This work presents the results of a new development to make basin-scale sea ice models aware of the shape, porosity and extent of individual ridges within the pack. We have derived an analytic solution for the Euler-Lagrange equation of individual ridges that accounts for non-conservative forces, and therefore the compressive strength of individual ridges. Because a region of the pack is simply a collection of paths of individual ridges, we are able to solve the Euler-Lagrange equation for a large-scale sea ice field also, and therefore the compressive strength of a region of the pack that explicitly accounts for the macro-porosity of ridged debris. We make a number of assumptions that have simplified the problem, such as treating sea ice as a granular material in ridges, and assuming that bending moments associated with ridging are perturbations around an isostatic state. Regardless of these simplifications, the ridge model is remarkably predictive of macro-porosity and ridge shape, and, because our equations are analytic, they do not require costly computations to solve the Euler-Lagrange equation of ridges on the large scale. The new ridge model is therefore applicable to large-scale sea ice models. We present results from this theoretical development, as well as plans to apply it to the Regional Arctic System Model and a community sea ice code. Most importantly, the new ridging model is particularly useful for pinpointing gaps in our observational record of sea ice ridges, and points to the need for improved measurements of the evolution of porosity of deformed ice in the Arctic and Antarctic. Such knowledge is not only useful for improving models, but also for improving estimates of sea ice volume derived from altimetric measurements of sea ice freeboard.

  3. Fault Management Metrics

    Science.gov (United States)

    Johnson, Stephen B.; Ghoshal, Sudipto; Haste, Deepak; Moore, Craig

    2017-01-01

    This paper describes the theory and considerations in the application of metrics to measure the effectiveness of fault management. Fault management refers here to the operational aspect of system health management, and as such is considered as a meta-control loop that operates to preserve or maximize the system's ability to achieve its goals in the face of current or prospective failure. As a suite of control loops, the metrics to estimate and measure the effectiveness of fault management are similar to those of classical control loops in being divided into two major classes: state estimation, and state control. State estimation metrics can be classified into lower-level subdivisions for detection coverage, detection effectiveness, fault isolation and fault identification (diagnostics), and failure prognosis. State control metrics can be classified into response determination effectiveness and response effectiveness. These metrics are applied to each and every fault management control loop in the system, for each failure to which they apply, and probabilistically summed to determine the effectiveness of these fault management control loops to preserve the relevant system goals that they are intended to protect.

  4. Fault isolability conditions for linear systems with additive faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

    In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...

  5. Transition from strike-slip faulting to oblique subduction: active tectonics at the Puysegur Margin, South New Zealand

    Science.gov (United States)

    Lamarche, Geoffroy; Lebrun, Jean-Frédéric

    2000-01-01

    South of New Zealand the Pacific-Australia (PAC-AUS) plate boundary runs along the intracontinental Alpine Fault, the Puysegur subduction front and the intraoceanic Puysegur Fault. The Puysegur Fault is located along Puysegur Ridge, which terminates at ca. 47°S against the continental Puysegur Bank in a complex zone of deformation called the Snares Zone. At Puysegur Trench, the Australian Plate subducts beneath Puysegur Bank and the Fiordland Massif. East of Fiordland and Puysegur Bank, the Moonlight Fault System (MFS) represents the Eocene strike-slip plate boundary. Interpretation of seafloor morphology and seismic reflection profiles acquired over Puysegur Bank and the Snares Zone allows study of the transition from intraoceanic strike-slip faulting along the Puysegur Ridge to oblique subduction at the Puysegur Trench and to better understand the genetic link between the Puysegur Fault and the MFS. Seafloor morphology is interpreted from a bathymetric dataset compiled from swath bathymetry data acquired during the 1993 Geodynz survey, and single beam echo soundings acquired by the NZ Royal Navy. The Snares Zone is the key transition zone from strike-slip faulting to subduction. It divides into three sectors, namely East, NW and SW sectors. A conspicuous 3600 m-deep trough (the Snares Trough) separates the NW and East sectors. The East sector is characterised by the NE termination of Puysegur Ridge into right-stepping en echelon ridges that accommodate a change of strike from the Puysegur Fault to the MFS. Between 48°S and 47°S, in the NW sector and the Snares Trough, a series of transpressional faults splay northwards from the Puysegur Fault. Between 49°50'S and 48°S, thrusts develop progressively at Puysegur Trench into a decollement. North of 48°S the Snares Trough develops between two splays of the Puysegur Fault, indicating superficial extension associated with the subsidence of Puysegur Ridge. Seismic reflection profiles and bathymetric maps show a

  6. The value of the absent bow tie sign in MRI of bucket-handle tears

    International Nuclear Information System (INIS)

    Watt, Andrew J.B.; Halliday, Tonya; Raby, Nigel

    2000-01-01

    AIM: To assess the accuracy of the absent bow tie sign in diagnosing bucket handle meniscal tears (BHT) of the knee menisci. MATERIALS AND METHODS: During a 3-year period, we correlated the MRI and arthroscopic findings and the presence of the various signs. One hundred and seven knees were reviewed: 74 where either MRI or arthroscopy had identified a BHT and 33 which were either normal (31), or a simple tear was identified (2). All cases were reviewed by a single radiologist with a musculoskeletal interest blinded to the original results. Each was assessed for the presence of (1) a central meniscal fragment, (2) the double posterior cruciate ligament (PCL) sign, (3) the bow tie sign and (4) the contribution of a 3D-volume sequence. RESULTS: Optimal results were obtained using standard sequences and a 3D-volume sequence, giving a sensitivity of 74% and positive predictive value of 89%. The bow tie sign gave a sensitivity of 71% and positive predictive value of 76%, significantly less than previous reports. The 18 BHTs diagnosed by arthroscopy but missed by MRI showed other abnormal findings at MRI and were not reported as normal. CONCLUSION: We were not able to reproduce the previously reported high sensitivity and specificity of the absent bow tie sign. Despite optimization of all factors, the accurate diagnosis of a bucket handle tear remains difficult, and is most reliably made by identifying a central meniscal fragment, rather than relying on secondary signs such as the absent bow tie sign. Watt, A.J.B. (2000)

  7. THEMIS satellite observations of hot flow anomalies at Earth's bow shock

    Directory of Open Access Journals (Sweden)

    C. Chu

    2017-03-01

    Full Text Available Hot flow anomalies (HFAs at Earth's bow shock were identified in Time History of Events and Macroscale Interactions During Substorms (THEMIS satellite data from 2007 to 2009. The events were classified as young or mature and also as regular or spontaneous hot flow anomalies (SHFAs. The dataset has 17 young SHFAs, 49 mature SHFAs, 15 young HFAs, and 55 mature HFAs. They span a wide range of magnetic local times (MLTs from approximately 7 to 16.5 MLT. The largest ratio of solar wind to HFA core density occurred near dusk and at larger distances from the bow shock. In this study, HFAs and SHFAs were observed up to 6.3 RE and 6.1 RE (Earth radii, respectively, upstream from the model bow shock. HFA–SHFA occurrence decreases with distance upstream from the bow shock. HFAs of the highest event core ion temperatures were not seen at the flanks. The ratio of HFA ion temperature increase to HFA electron temperature increase is highest around 12 MLT and slightly duskward. For SHFAs, (Tihfa∕Tisw/(Tehfa∕Tesw generally increased with distance from the bow shock. Both mature and young HFAs are more prevalent when there is an approximately radial interplanetary magnetic field. HFAs occur most preferentially for solar wind speeds from 550 to 600 km s−1. The correlation coefficient between the HFA increase in thermal energy density from solar wind values and the decrease in kinetic energy density from solar wind values is 0.62. SHFAs and HFAs do not show major differences in this study.

  8. Fault Analysis in Cryptography

    CERN Document Server

    Joye, Marc

    2012-01-01

    In the 1970s researchers noticed that radioactive particles produced by elements naturally present in packaging material could cause bits to flip in sensitive areas of electronic chips. Research into the effect of cosmic rays on semiconductors, an area of particular interest in the aerospace industry, led to methods of hardening electronic devices designed for harsh environments. Ultimately various mechanisms for fault creation and propagation were discovered, and in particular it was noted that many cryptographic algorithms succumb to so-called fault attacks. Preventing fault attacks without

  9. Bookshelf faulting and transform motion between rift segments of the Northern Volcanic Zone, Iceland

    Science.gov (United States)

    Green, R. G.; White, R. S.; Greenfield, T. S.

    2013-12-01

    Plate spreading is segmented on length scales from 10 - 1,000 kilometres. Where spreading segments are offset, extensional motion has to transfer from one segment to another. In classical plate tectonics, mid-ocean ridge spreading centres are offset by transform faults, but smaller 'non-transform' offsets exist between slightly overlapping spreading centres which accommodate shear by a variety of geometries. In Iceland the mid-Atlantic Ridge is raised above sea level by the Iceland mantle plume, and is divided into a series of segments 20-150 km long. Using microseismicity recorded by a temporary array of 26 three-component seismometers during 2009-2012 we map bookshelf faulting between the offset Askja and Kverkfjöll rift segments in north Iceland. The micro-earthquakes delineate a series of sub-parallel strike-slip faults. Well constrained fault plane solutions show consistent left-lateral motion on fault planes aligned closely with epicentral trends. The shear couple across the transform zone causes left-lateral slip on the series of strike-slip faults sub-parallel to the rift fabric, causing clockwise rotations about a vertical axis of the intervening rigid crustal blocks. This accommodates the overall right-lateral transform motion in the relay zone between the two overlapping volcanic rift segments. The faults probably reactivated crustal weaknesses along the dyke intrusion fabric (parallel to the rift axis) and have since rotated ˜15° clockwise into their present orientation. The reactivation of pre-existing rift-parallel weaknesses is in contrast with mid-ocean ridge transform faults, and is an important illustration of a 'non-transform' offset accommodating shear between overlapping spreading segments.

  10. Fault tolerant control based on active fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2005-01-01

    An active fault diagnosis (AFD) method will be considered in this paper in connection with a Fault Tolerant Control (FTC) architecture based on the YJBK parameterization of all stabilizing controllers. The architecture consists of a fault diagnosis (FD) part and a controller reconfiguration (CR......) part. The FTC architecture can be applied for additive faults, parametric faults, and for system structural changes. Only parametric faults will be considered in this paper. The main focus in this paper is on the use of the new approach of active fault diagnosis in connection with FTC. The active fault...... diagnosis approach is based on including an auxiliary input in the system. A fault signature matrix is introduced in connection with AFD, given as the transfer function from the auxiliary input to the residual output. This can be considered as a generalization of the passive fault diagnosis case, where...

  11. Quaternary Fault Lines

    Data.gov (United States)

    Department of Homeland Security — This data set contains locations and information on faults and associated folds in the United States that are believed to be sources of M>6 earthquakes during the...

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

    International Nuclear Information System (INIS)

    Lu Quanming; Shan Lican; Zhang Tielong; Wu Mingyu; Wang Shui; Zank, Gary P.; Yang Zhongwei; Du Aimin

    2013-01-01

    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

  13. Fault lubrication during earthquakes.

    Science.gov (United States)

    Di Toro, G; Han, R; Hirose, T; De Paola, N; Nielsen, S; Mizoguchi, K; Ferri, F; Cocco, M; Shimamoto, T

    2011-03-24

    The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved.

  14. Vipava fault (Slovenia

    Directory of Open Access Journals (Sweden)

    Ladislav Placer

    2008-06-01

    Full Text Available During mapping of the already accomplished Razdrto – Senožeče section of motorway and geologic surveying of construction operations of the trunk road between Razdrto and Vipava in northwestern part of External Dinarides on the southwestern slope of Mt. Nanos, called Rebrnice, a steep NW-SE striking fault was recognized, situated between the Predjama and the Ra{a faults. The fault was named Vipava fault after the Vipava town. An analysis of subrecent gravitational slips at Rebrnice indicates that they were probably associated with the activity of this fault. Unpublished results of a repeated levelling line along the regional road passing across the Vipava fault zone suggest its possible present activity. It would be meaningful to verify this by appropriate geodetic measurements, and to study the actual gravitational slips at Rebrnice. The association between tectonics and gravitational slips in this and in similar extreme cases in the areas of Alps and Dinarides points at the need of complex studying of geologic proceses.

  15. Effects of Cocos Ridge Collision on the Western Caribbean: Is there a Panama Block?

    Science.gov (United States)

    Kobayashi, D.; La Femina, P. C.; Geirsson, H.; Chichaco, E.; Abrego M, A. A.; Fisher, D. M.; Camacho, E. I.

    2011-12-01

    earthquake relocation and geologic data are used to define block boundaries and fault geometries. We invert the three-dimensional GPS velocity vectors and earthquake slip vectors to estimate the magnitude and spatial distribution of interplate mechanical coupling on active plate and block boundaries around the Panama block; the Middle America Trench - South Panama Deformed Belt, the Central Costa Rican Deformed Belt, and the North Panama Deformed Belt in particular, and the rates of relative plate motion between the Panama block and the adjacent Cocos, Nazca, and Caribbean plates. This study tests whether the Panama block responds to the ridge collision as a rigid tectonic block or as a deforming zone consisting of multiple blocks.

  16. RCRA Facility investigation report for Waste Area Grouping 6 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1991-09-01

    This report describes the borehole geophysical logging performed at selected monitoring wells at waste area grouping (WAG) 6 of Oak Ridge National Laboratory in support of the WAG 6 Resource Conservation and Recovery Act Facility Investigation (RFI). It identifies the locations and describes the methods, equipment used in the effort, and the results of the activity. The actual logs for each well logged are presented in Attachment 1 through 4 of the TM. Attachment 5 provide logging contractor service literature and Attachment 6 is the Oak Ridge National Laboratory (ORNL) Procedure for Control of a Nuclear Source Utilized in Geophysical logging. The primary objectives of the borehole geophysical logging program were to (1) identify water-bearing fractured bedrock zones to determine the placement of the screen and sealed intervals for subsequent installation, and (2) further characterize local bedrock geology and hydrogeology and gain insight about the deeper component of the shallow bedrock aquifer flow system. A secondary objective was to provide stratigraphic and structural correlations with existing logs for Hydraulic Head Monitoring Station (HHMS) wells, which display evidence of faulting

  17. Fault morphology of the lyo Fault, the Median Tectonic Line Active Fault System

    OpenAIRE

    後藤, 秀昭

    1996-01-01

    In this paper, we investigated the various fault features of the lyo fault and depicted fault lines or detailed topographic map. The results of this paper are summarized as follows; 1) Distinct evidence of the right-lateral movement is continuously discernible along the lyo fault. 2) Active fault traces are remarkably linear suggesting that the angle of fault plane is high. 3) The lyo fault can be divided into four segments by jogs between left-stepping traces. 4) The mean slip rate is 1.3 ~ ...

  18. Emergency preparedness at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Skipper, M.N.

    1990-03-01

    Emergency preparedness for industry was commonly believed to be an essential responsibility on the part of management. Therefore, this study was conducted to research and accumulate information and data on emergency preparedness at Oak Ridge National Laboratory (ORNL). The objective of this study was to conduct a thorough evaluation of emergency preparedness knowledge among employees to determine if they were properly informed or if they needed more training. Also, this study was conducted to provide insight to management as to what their responsibility was concerning this training. To assess employee emergency preparedness knowledge, a questionnaire was developed and administered to 100 employees at ORNL. The data was analyzed using frequencies and percentages of response and was displayed through the use of graphs within the report. 22 refs., 22 figs

  19. Emergency preparedness at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Skipper, M.N.

    1990-03-01

    Emergency preparedness for industry was commonly believed to be an essential responsibility on the part of management. Therefore, this study was conducted to research and accumulate information and data on emergency preparedness at Oak Ridge National Laboratory (ORNL). The objective of this study was to conduct a thorough evaluation of emergency preparedness knowledge among employees to determine if they were properly informed or if they needed more training. Also, this study was conducted to provide insight to management as to what their responsibility was concerning this training. To assess employee emergency preparedness knowledge, a questionnaire was developed and administered to 100 employees at ORNL. The data was analyzed using frequencies and percentages of response and was displayed through the use of graphs within the report. 22 refs., 22 figs.

  20. HYDROLOGIC CHARACTERISTICS OF FAULTS AT YUCCA MOUNTAIN, NEVADA

    International Nuclear Information System (INIS)

    R.P. Dickerson

    2000-01-01

    Yucca Mountain comprises a series of north-trending ridges composed of tuffs within the southwest Nevada volcanic field, 120 km northwest of Las Vegas, Nevada. These ridges are formed of east-dipping blocks of interbedded welded and nonwelded tuff that are offset along steep, mostly west-dipping faults that have tens to hundreds of meters of vertical separation. Yucca Mountain is currently under study as a potential site for underground storage of high-level radioactive waste, with the principle goal being the safe isolation of the waste from the accessible environment. To this end, an understanding of the behavior of ground-water flow through the mountain in the unsaturated zone and beneath the mountain in the saturated zone is critical. The percolation of water through the mountain and into the ground-water flow system beneath the potential repository site is predicated on: (1) the amount of water available at the surface as a result of the climatic conditions, (2) the hydrogeologic characteristics of the volcanic strata that compose the mountain. and (3) the hydrogeologic characteristics of the structures, particularly fault zones and fracture networks, that disrupt these strata. This paper addresses the hydrogeologic characteristics of the fault zones at Yucca Mountain, focusing primarily on the central part of the mountain where the potential repository block is located

  1. Metallogenesis along the Indian Ocean Ridge System

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Ray, Dwijesh

    including India. Among these studies majority were concentrated around the Central Indian Ridge and the Southwest Indian Ridge areas, while a few observations were made around the rest of the areas in the IORS. The findings of these studies are discussed...

  2. Sex Determination from Fingerprint Ridge Density | Gungadin ...

    African Journals Online (AJOL)

    This study was conducted with an aim to establish a relationship between sex and fingerprint ridge density. The fingerprints were taken from 500 subjects (250 males and 250 females) in the age group of 18-60 years. After taking fingerprints, the ridges were counted in the upper portion of the radial border of each print for all ...

  3. Systematic search for very-high-energy gamma-ray emission from bow shocks of runaway stars

    Science.gov (United States)

    H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Coffaro, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'C.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Richter, S.; Rieger, F.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stycz, K.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.

    2018-04-01

    Context. Runaway stars form bow shocks by ploughing through the interstellar medium at supersonic speeds and are promising sources of non-thermal emission of photons. One of these objects has been found to emit non-thermal radiation in the radio band. This triggered the development of theoretical models predicting non-thermal photons from radio up to very-high-energy (VHE, E ≥ 0.1 TeV) gamma rays. Subsequently, one bow shock was also detected in X-ray observations. However, the data did not allow discrimination between a hot thermal and a non-thermal origin. Further observations of different candidates at X-ray energies showed no evidence for emission at the position of the bow shocks either. A systematic search in the Fermi-LAT energy regime resulted in flux upper limits for 27 candidates listed in the E-BOSS catalogue. Aim. Here we perform the first systematic search for VHE gamma-ray emission from bow shocks of runaway stars. Methods: Using all available archival H.E.S.S. data we search for very-high-energy gamma-ray emission at the positions of bow shock candidates listed in the second E-BOSS catalogue release. Out of the 73 bow shock candidates in this catalogue, 32 have been observed with H.E.S.S. Results: None of the observed 32 bow shock candidates in this population study show significant emission in the H.E.S.S. energy range. Therefore, flux upper limits are calculated in five energy bins and the fraction of the kinetic wind power that is converted into VHE gamma rays is constrained. Conclusions: Emission from stellar bow shocks is not detected in the energy range between 0.14 and 18 TeV.The resulting upper limits constrain the level of VHE gamma-ray emission from these objects down to 0.1-1% of the kinetic wind energy.

  4. Ridge interaction features of the Line Islands

    Science.gov (United States)

    Konter, J. G.; Koppers, A. A. P.; Storm, L. P.

    2016-12-01

    The sections of Pacific absolute plate motion history that precede the Hawaii-Emperor and Louisville chains are based on three chains: the Line Islands-Mid-Pacific Mountains, the Hess Rise-Shatsky Rise, and the Marshall Islands-Wake Islands (Rurutu hotspot). Although it has been clear that the Line Islands do not define a simple age progression (e.g. Schlanger et al., 1984), the apparent similarity to the Emperor Seamount geographic trend has been used to extend the overall Hawaii-Emperor track further into the past. However, we show here that plate tectonic reconstructions suggest that the Mid-Pacific Mountains (MPMs) and Line Islands (LIs) were erupted near a mid-ocean ridge, and thus these structures do not reflect absolute plate motion. Moverover, the morphology and geochemistry of the volcanoes show similarities with Pukapuka Ridge (e.g. Davis et al., 2002) and the Rano Rahi seamounts, presumed to have a shallow origin. Modern 40Ar/39Ar ages show that the LIs erupted at various times along the entire volcanic chain. The oldest structures formed within 10 Ma of plate formation. Given the short distance to the ridge system, large aseismic volcanic ridges, such as Necker Ridge and Horizon Guyot may simply reflect a connection between MPMs and the ridge, similar to the Pukapuka Ridge. The Line Islands to the south (including Karin Ridge) define short subchains of elongated seamounts that are widespread, resembling the Rano Rahi seamount field. During this time, the plate moved nearly parallel to the ridge system. The change from few large ridges to many subchains may reflect a change in absolute plate motion, similar to the Rano Rahi field. Here, significant MPMs volcanism is no longer connected to the ridge along plate motion. Similar to Pukapuka vs. Rano Rahi, the difference in direction between plate motion and the closest ridge determines whether larger ridges or smaller seamount subchains are formed. The difference between the largest structures (MPMs and LIs

  5. Ion distributions in the Earth's foreshock upstream from the bow shock

    Science.gov (United States)

    Fuselier, S. A.

    1995-01-01

    A variety of suprathermal and energetic ion distributions are found upstream from shocks. Some distributions, such as field-aligned beams, are generated directly at the shock either through reflection processes or through leakage from the hotter downstream region. Other distributions, such as intermediate distributions, evolve from these parent distributions through wave-particle interactions. This paper reviews our current understanding of the creation and evolution of suprathermal distributions at shocks. Examples of suprathermal ion distributions are taken from observations at the Earth's bow shock. Particular emphasis is placed on the creation of field-aligned beams and specularly reflected ion distributions and on the evolution of these distributions in the Earth's ion foreshock. However, the results from this heavily studied region are applicable to interplanetary shocks, bow shocks at other planets, and comets.

  6. Ion distributions upstream and downstream of the Earth's bow shock: first results from Vlasiator

    Directory of Open Access Journals (Sweden)

    D. Pokhotelov

    2013-12-01

    Full Text Available A novel hybrid-Vlasov code, Vlasiator, is developed for global simulations of magnetospheric plasma kinetics. The code is applied to model the collisionless bow shock on scales of the Earth's magnetosphere in two spatial dimensions and three dimensions in velocity space retrieving ion distribution functions over the entire foreshock and magnetosheath regions with unprecedented detail. The hybrid-Vlasov approach produces noise-free uniformly discretized ion distribution functions comparable to those measured in situ by spacecraft. Vlasiator can reproduce features of the ion foreshock and magnetosheath well known from spacecraft observations, such as compressional magnetosonic waves generated by backstreaming ion populations in the foreshock and mirror modes in the magnetosheath. An overview of ion distributions from various regions of the bow shock is presented, demonstrating the great opportunities for comparison with multi-spacecraft observations.

  7. 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.

  8. Predictions of lithium interactions with earth's bow shock in the presence of wave activity

    Science.gov (United States)

    Decker, R. B.; Lui, A. T. Y.; Vlahos, L.

    1984-01-01

    The results of a test-particle simulation studying the movement of a lithium tracer ion injected upstream of the bow shock are reported. Wave activity consists of parallel and antiparallel propagating Alfven waves characterized by a frequency power spectrum within a frequency or range of amplitudes defined separately in the upstream and downstream regions. The results show that even a moderate level of wave activity can substantially change the results obtained in the absence of waves. Among the effects observed are: (1) increased ion transmission; (2) both the average energy gain and spread about the average are increased for transmitted and reflected particles; (3) the average final pitch angle for transmitted particles tends to 90 deg, and the spread of reflected particles is reduced; and (4) the spatial dispersion of the ions on the bow shock after a single encounter is increased.

  9. Sensitivity of reactivity feedback due to core bowing in a metallic-fueled core

    International Nuclear Information System (INIS)

    Nakagawa, Masatoshi; Kawashima, Masatoshi; Endo, Hiroshi; Nishimura, Tomohiro

    1991-01-01

    A sensitivity study has been carried out on negative reactivity feedback caused by core bowing to assess the potential effectiveness of FBR passive safety features in regard to withstanding an anticipated transient without scram (ATWS). In the present study, an analysis has been carried to obtain the best material and geometrical conditions concerning the core restraint system out for several power to flow rates (P/F), up to 2.0 for a 300 MWe metallic-fueled core. From this study, it was clarified that the pad stiffness at an above core loading pads (ACLP) needs to be large enough to ensure negative reactivity feedback against ATWS. It was also clarified that there is an upper limit for the clearances between ducts at ACLP. A new concept, in regard to increasing the absolute value for negative reactivity feedback due to core bowing at ATWS, is proposed and discussed. (author)

  10. Nonthermal ions and associated magnetic field behavior at a quasi-parallel earth's bow shock

    Science.gov (United States)

    Wilkinson, W. P.; Pardaens, A. K.; Schwartz, S. J.; Burgess, D.; Luehr, H.; Kessel, R. L.; Dunlop, M.; Farrugia, C. J.

    1993-01-01

    Attention is given to ion and magnetic field measurements at the earth's bow shock from the AMPTE-UKS and -IRM spacecraft, which were examined in high time resolution during a 45-min interval when the field remained closely aligned with the model bow shock normal. Dense ion beams were detected almost exclusively in the midst of short-duration periods of turbulent magnetic field wave activity. Many examples of propagation at large elevation angles relative to the ecliptic plane, which is inconsistent with reflection in the standard model shock configuration, were discovered. The associated waves are elliptically polarized and are preferentially left-handed in the observer's frame of reference, but are less confined to the maximum variance plane than other previously studied foreshock waves. The association of the wave activity with the ion beams suggests that the former may be triggered by an ion-driven instability, and possible candidates are discussed.

  11. Bimanual coordination of bowing and fingering in violinists--effects of position changes and string changes.

    Science.gov (United States)

    Kazennikov, Oleg; Wiesendanger, Mario

    2009-07-01

    Music performance is based on demanding motor control with much practice from young age onward. We have chosen to investigate basic bimanual movements played by violin amateurs and professionals. We posed the question whether position and string changes, two frequent mechanisms, may influence the time interval bowing (right)-fingering (left) coordination. The objective was to measure bimanual coordination, i.e., with or without position changes and string changes. The tendency was that the bimanual coordination was statistically only slightly increased or even unchanged but not perceptible. We conclude that the coordination index is limited up to 100 ms intervals, without any erroneous perception. Although the mentioned position changes and string changes are movements with their timing, they are executed in parallel rather than in series with the bow-fingering coordination.

  12. Observations of two distinct populations of bow shock ions in the upstream solar wind

    International Nuclear Information System (INIS)

    Gosling, J.T.; Asbridge, J.; Bame, S.J.; Paschmann, G.; Sckopke, N.

    1978-01-01

    Observations upstream of the earth's bow shock with the LASL/MPI fast plasma experiments on ISEE 1 and 2 reveal the presence of two distinct and mutually exclusive populations of low energy (< or approx. =40keV) ions apparently accelerated at the bow shock. The first of these, the ''reflected'' population, is characterized by 1) sharply peaked spectra seldom extending much above approx. 10 keV/ion and 2) relatively collimated flow coming from the direction of the shock. On the other hand, the ''diffuse'' ions are distinguished by relatively flat energy spectra above approx. 10 keV and broad angular distributions. They are by far the most commonly observed upstream ion event. A close causal association is suggested between the diffuse ion population in the upstream solar wind and energetic plasma ions observed within the magnetosheath

  13. MMS Observation of Shock-Reflected He++ at Earth's Quasi-Perpendicular Bow Shock

    Science.gov (United States)

    Broll, Jeffrey Michael; Fuselier, S. A.; Trattner, K. J.; Schwartz, S. J.; Burch, J. L.; Giles, B. L.; Anderson, B. J.

    2018-01-01

    Specular reflection of protons at Earth's supercritical quasi-perpendicular bow shock has long been known to lead to the thermalization of solar wind particles by velocity-space dispersion. The same process has been proposed for He++ but could not be confirmed previously due to insufficient time resolution for velocity distribution measurements. We present observations and simulations of a bow shock crossing by the Magnetospheric Multiscale (MMS) mission on 20 November 2015 indicating that a very similar reflection process for He++ is possible, and further that the part of the incoming distribution with the highest probability of reflecting is the same for H+ and He++. However, the reflection process for He++ is accomplished by deeper penetration into the downstream magnetic fields.

  14. The electron density and temperature distributions predicted by bow shock models of Herbig-Haro objects

    International Nuclear Information System (INIS)

    Noriega-Crespo, A.; Bohm, K.H.; Raga, A.C.

    1990-01-01

    The observable spatial electron density and temperature distributions for series of simple bow shock models, which are of special interest in the study of Herbig-Haro (H-H) objects are computed. The spatial electron density and temperature distributions are derived from forbidden line ratios. It should be possible to use these results to recognize whether an observed electron density or temperature distribution can be attributed to a bow shock, as is the case in some Herbig-Haro objects. As an example, the empirical and predicted distributions for H-H 1 are compared. The predicted electron temperature distributions give the correct temperature range and they show very good diagnostic possibilities if the forbidden O III (4959 + 5007)/4363 wavelength ratio is used. 44 refs

  15. Oak Ridge Reservation environmental report for 1991

    International Nuclear Information System (INIS)

    Mucke, P.C.

    1992-10-01

    The Oak Ridge Reservation Environmental Report for 1991 is the 21st in a series that began in 1971. The report documents the annual results of a comprehensive program to estimate the impact of the US Department of Energy (DOE) Oak Ridge operations upon human health and the environment. The report is organized into ten sections that address various aspects of effluent monitoring, environmental surveillance, dose assessment, waste management, and quality assurance. A compliance summary gives a synopsis of the status of each facility relative to applicable state and federal regulations. Data are included for the following: Oak Ridge Y-12 Plant; Oak Ridge National Laboratory (ORNL); and Oak Ridge K-25 Site. Effluent monitoring and environmental surveillance programs are intended to serve as effective indicators of contaminant releases and ambient contaminant concentrations that have the potential to result in adverse impacts to human health and the environment

  16. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated......Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...

  17. Risk assessment in gas and oil pipelines based on the fuzzy Bow-tie technique

    OpenAIRE

    P. Heyrani; A. Baghaei

    2016-01-01

    Introduction: Nowadays, gas and oil account for 60 percent of world energy resources. Transporting crude oil and its products are accomplished through a number of ways among which pipelines are of the utmost significance. Considering the extent of pipelines in installation and residential areas and also high potential for damage, the safety of these pipes and application of risk management principles have undeniable importance. Bow-tie risk assessment method is one of the ways to determine sa...

  18. Coupled hydromagnetic wave excitation and ion acceleration upstream of the earth's bow shock

    International Nuclear Information System (INIS)

    Lee, M.A.

    1982-01-01

    A self-consistent theory is presented for the excitation of hydromagnetic waves and the acceleration of diffuse ions upstream of the earth's bow shock in the quasi-equilibrium that results when the solar wind velocity and the interplanetary magnetic field are nearly parallel. For the waves the quasi-equilibrium results from a balance between excitation by the ions, which stream relative to the solar wind plasma, and convective loss to the magnetosheath. For the diffuse ions the quasi-equilibrium results from a balance between injection at the shock front, confinement to the foreshock by pitch angle scattering on the waves, acceleration by compression at the shock front, loss to the magnetosheath, loss due to escape upstream of the foreshock, and loss via diffusion perpendicular to the average magnetic field onto field lines that do not connect to the shock front. Diffusion equations describing the ion transport and wave kinetic equations describing the hydromagnetic wave transport are solved self-consistently to yield analytical expressions for the differential wave intensity spectrum as a function of frequency and distance from the bow shock z and for the ion omnidirectional distribution functions and anisotropies as functions of energy and z, In quantitative agreement with observations, the theory predicts (1) exponential spectra at the bow shock in energy per charge, (2) a decrease in intensity and hardening of the ion spectra with increasing z, (3) a 30-keV proton anisotropy parallel to z increasing from -0.28 at the bow shock to +0.51 as z→infinity (4) a linearly polarized wave intensity spectrum with a minimum at approx.6 x 10 -3 Hz and a maximum at approx.2--3 x 10 -2 Hz, (5) a decrease in the wave intensity spectrum with increasing z, (6) a total energy density in protons with energies >15 keV about eight times that in the hydromagnetic waves

  19. Observation of Motion of Bowed Strings and Resonant Strings in Violin Performances

    Science.gov (United States)

    Matsutani, Akihiro

    2013-10-01

    The motion of a bowed string and a resonant string of a violin were simultaneously observed for the first time. The results of the direct observation of string motion in double stops and harmonics are also presented. The importance of the resonance was experimentally demonstrated from these observations. It is suggested that players should take account of the resonance and ideal Helmholtz motion in violin performances.

  20. The Fruits of Adversity: Technical Refinements of the Turkish Composite Bow during the Crusading Era

    Science.gov (United States)

    1991-01-01

    period. Depictions of these two bows are found in the detailed reproductions of sculptures, architectural reliefs, metalworkings, bone carvings, ivory...34 Ecclesiastical History of 12 In European battles at this time, heavy cavalry was unchallenged as the offensive arm in battle.4 Since the time of...Marzial, Great Britain: Aldine Press, 1965. Vitalis, Ordericus, The Ecclesiastical History of England and Normandy, trans. by Thomas Forester, London

  1. Laboratory studies of stagnating plasma flows with applications to inner solar system and stellar bow shocks

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2016-10-01

    Supercritical magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe by converting flow kinetic energy to other forms such as thermal and supra-thermal populations, magnetic field enhancement, turbulence, and energetic particles. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those of inner solar system and stellar bow shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to 100s of km/s; resulting in β 1, collisionless plasma flows with Msonic and MAlfvén 10. The drifting FRC can be made to impinge upon a variety of static obstacles including: a strong mirror or cusp magnetic field (mimicking magnetically excited shocks such as the Earth's bow shock), plasma pileup from a solid obstacle (similar to the bow shocks of Mercury and the Moon), and a neural gas puff (bow shocks of Venus or the comets). Characteristic shock length and time scales that are both large enough to observe yet small enough to fit within the experiment, enabling study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental program will be presented, including recent results. This work is supported by the U.S. DOE, Office of Science, Office of Fusion Energy Sciences under Contract No. DE-AC52-06NA25369.

  2. Serendipitous discovery of an infrared bow shock near PSR J1549–4848 with Spitzer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhongxiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Kaplan, David L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Slane, Patrick [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Morrell, Nidia [Las Campanas Observatory, Observatories of the Carnegie Institution of Washington, La Serena (Chile); Kaspi, Victoria M. [Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada)

    2013-06-01

    We report on the discovery of an infrared cometary nebula around PSR J1549–4848 in our Spitzer survey of a few middle-aged radio pulsars. Following the discovery, multi-wavelength imaging and spectroscopic observations of the nebula were carried out. We detected the nebula in Spitzer Infrared Array Camera 8.0, Multiband Imaging Photometer for Spitzer 24 and 70 μm imaging, and in Spitzer IRS 7.5-14.4 μm spectroscopic observations, and also in the Wide-field Infrared Survey Explorer all-sky survey at 12 and 22 μm. These data were analyzed in detail, and we find that the nebula can be described with a standard bow shock shape, and that its spectrum contains polycyclic aromatic hydrocarbon and H{sub 2} emission features. However, it is not certain which object drives the nebula. We analyze the field stars and conclude that none of them can be the associated object because stars with a strong wind or mass ejection that usually produce bow shocks are much brighter than the field stars. The pulsar is approximately 15'' away from the region in which the associated object is expected to be located. In order to resolve the discrepancy, we suggest that a highly collimated wind could be emitted from the pulsar and produce the bow shock. X-ray imaging to detect the interaction of the wind with the ambient medium- and high-spatial resolution radio imaging to determine the proper motion of the pulsar should be carried out, which will help verify the association of the pulsar with the bow shock nebula.

  3. Controls on intrusion of near-trench magmas of the Sanak-Baranof Belt, Alaska, during Paleogene ridge subduction, and consequences for forearc evolution

    Science.gov (United States)

    Kusky, Timothy M.; Bradley, Dwight C.; Donely, D. Thomas; Rowley, David; Haeussler, Peter J.

    2003-01-01

    A belt of Paleogene near-trench plutons known as the Sanak-Baranof belt intruded the southern Alaska convergent margin. A compilation of isotopic ages of these plutons shows that they range in age from 61 Ma in the west to ca. 50 Ma in the east. This migrating pulse of magmatism along the continental margin is consistent with North Pacific plate reconstructions that suggests the plutons were generated by migration of a trench-ridge-trench triple junction along the margin. On the Kenai Peninsula the regional lower greenschist metamorphic grade of the turbiditic host rocks, texture of the plutons, contact-metamorphic assemblage, and isotopic and fluid inclusion studies suggest that the plutons were emplaced at pressures of 1.5–3.0 kbars (5.2–10.5 km) into a part of the accretionary wedge with an ambient temperature of 210–300 °C. The presence of kyanite, garnet, and cordierite megacrysts in the plutons indicates that the melts were generated at a depth greater than 20 km and minimum temperature of 650 °C. These megacrysts are probably xenocrystic remnants of a restitic or contact metamorphic phase entrained by the melt during intrusion. However, it is also possible that they are primary magmatic phases crystallized from the peraluminous melt.Plutons of the Sanak-Baranof belt serve as time and strain markers separating kinematic regimes that predate and postdate ridge subduction. Pre-ridge subduction structures are interpreted to be related to the interaction between the leading oceanic plate and the Chugach terrane. These include regional thrust faults, NE-striking map-scale folds with associated axial planar foliation, type-1 mélanges, and an arrayof faults within the contact aureole indicating shortening largely accommodated by layer-parallel extension. Syn-ridge subduction features include the plutons, dikes, and ductile shear zones within contact aureoles with syn-kinematic metamorphic mineral growth and foliation development. Many of the studied plutons

  4. Wafer bowing control of free-standing heteroepitaxial diamond (100) films grown on Ir(100) substrates via patterned nucleation growth

    International Nuclear Information System (INIS)

    Yoshikawa, Taro; Kodama, Hideyuki; Kono, Shozo; Suzuki, Kazuhiro; Sawabe, Atsuhito

    2015-01-01

    The potential of patterned nucleation growth (PNG) technique to control the wafer bowing of free-standing heteroepitaxial diamond films was investigated. The heteroepitaxial diamond (100) films were grown on an Ir(100) substrate via PNG technique with different patterns of nucleation regions (NRs), which were dot-arrays with 8 or 13 μm pitch aligned to < 100 > or < 110 > direction of the Ir(100) substrate. The wafer bows and the local stress distributions of the free-standing films were measured using a confocal micro-Raman spectrometer. For each NR pattern, the stress evolutions within the early stage of diamond growth were also studied together with a scanning electron microscopic observation of the coalescing diamond particles. These investigations revealed that the NR pattern, in terms of pitch and direction of dot-array, strongly affects the compressive stress on the nucleation side of the diamond film and dominantly contributes to the elastic deformation of the free-standing film. This indicates that the PNG technique with an appropriate NR pattern is a promising solution to fabricate free-standing heteroepitaxial diamond films with extremely small bows. - Highlights: • Wafer bowing control of free-standing heteroepitaxial diamond (100) films • Effect of patterned nucleation and growth (PNG) technique on wafer bowing reduction • Influence of nucleation region patterns of PNG on wafer bowing • Internal stress analysis of PNG films via confocal micro-Raman spectroscopy

  5. The Procedure for Determination of Special Margin Factors to Account for a Bow of the VVER-1000 Fuel Assemblies

    International Nuclear Information System (INIS)

    Tsyganov, Sergey V.; Marin, Stanislav V.; Shishkov, Lev K.

    2008-01-01

    Starting from 1980's, the problem of bow of the VVER-1000 reactor FAs and the effect of that on the operational safety is being discussed. At the initial period of time, the extension of time for dropping control rods of the control and protection system associated with this bow posed the highest threat. Later on, new more rigid structures were developed for FAs that eliminated the problems of control rods. However, bow of the VVER-1000 reactor FAs is observed up to now. The scale of this bow reduced significantly but it still effects safety. Even a minor bow available may lead to the noticeable increase of power of individual fuel pins associated with the local variation of the coolant amount. This effect must be taken into account on designing fuel loadings to eliminate the exceeding of set limitations. The introduction of additional special margins is the standard method for taking this effect into account. The present paper describes the conservative technique for the assessment of additional margins for bow of FAs of state-of-the-art designs. This technique is employed in the VVER-1000 reactor designing. The chosen conservatism degree is discussed as well as the method for its assurance and acceptable ways for its slackening. The example of the margin evaluation for the up-to-date fuel loading is given. (authors)

  6. The procedure for determination of special margin factors to account for a bow of the WWER-1000 fuel assemblies

    International Nuclear Information System (INIS)

    Tsyganov, S. V.; Marin, S. V.; Shishkov, L. K.

    2008-01-01

    Starting from 1980s, the problem of bow of the WWER-1000 reactor fuel assemblies and the effect of that on the operational safety is being discussed. At the initial period of time, the extension of time for dropping control rods of the control and protection system associated with this bow posed the highest threat. Later on, new more rigid structures were developed for fuel assemblies that eliminated the problems of control rods. However, bow of the WWER-1000 reactor fuel assemblies is observed up to now. The scale of this bow reduced significantly but it still effects safety. Even a minor bow available may lead to the noticeable increase of power of individual fuel pins associated with the local variation of the coolant amount. This effect must be taken into account on designing fuel loadings to eliminate the exceeding of set limitations. The introduction of additional special margins is the standard method for taking this effect into account. The present paper describes the conservative technique for the assessment of additional margins for bow of fuel assemblies of state-of-the-art designs. This technique is employed in the WWER-1000 reactor designing. The chosen conservatism degree is discussed as well as the method for its assurance and acceptable ways for its slackening. The example of the margin evaluation for the up-to-date fuel loading is given. (authors)

  7. The Procedure for Determination of Special Margin Factors to Account for a Bow of the VVER-1000 Fuel Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Tsyganov, Sergey V.; Marin, Stanislav V.; Shishkov, Lev K. [Russian Research Center ' Kurchatov Institute' , 1., Kurchatov sq., 123182 Moscow (Russian Federation)

    2008-07-01

    Starting from 1980's, the problem of bow of the VVER-1000 reactor FAs and the effect of that on the operational safety is being discussed. At the initial period of time, the extension of time for dropping control rods of the control and protection system associated with this bow posed the highest threat. Later on, new more rigid structures were developed for FAs that eliminated the problems of control rods. However, bow of the VVER-1000 reactor FAs is observed up to now. The scale of this bow reduced significantly but it still effects safety. Even a minor bow available may lead to the noticeable increase of power of individual fuel pins associated with the local variation of the coolant amount. This effect must be taken into account on designing fuel loadings to eliminate the exceeding of set limitations. The introduction of additional special margins is the standard method for taking this effect into account. The present paper describes the conservative technique for the assessment of additional margins for bow of FAs of state-of-the-art designs. This technique is employed in the VVER-1000 reactor designing. The chosen conservatism degree is discussed as well as the method for its assurance and acceptable ways for its slackening. The example of the margin evaluation for the up-to-date fuel loading is given. (authors)

  8. Fault Detection for Industrial Processes

    Directory of Open Access Journals (Sweden)

    Yingwei Zhang

    2012-01-01

    Full Text Available A new fault-relevant KPCA algorithm is proposed. Then the fault detection approach is proposed based on the fault-relevant KPCA algorithm. The proposed method further decomposes both the KPCA principal space and residual space into two subspaces. Compared with traditional statistical techniques, the fault subspace is separated based on the fault-relevant influence. This method can find fault-relevant principal directions and principal components of systematic subspace and residual subspace for process monitoring. The proposed monitoring approach is applied to Tennessee Eastman process and penicillin fermentation process. The simulation results show the effectiveness of the proposed method.

  9. Structural Evolution of Transform Fault Zones in Thick Oceanic Crust of Iceland

    Science.gov (United States)

    Karson, J. A.; Brandsdottir, B.; Horst, A. J.; Farrell, J.

    2017-12-01

    Spreading centers in Iceland are offset from the regional trend of the Mid-Atlantic Ridge by the Tjörnes Fracture Zone (TFZ) in the north and the South Iceland Seismic Zone (SISZ) in the south. Rift propagation away from the center of the Iceland hotspot, has resulted in migration of these transform faults to the N and S, respectively. As they migrate, new transform faults develop in older crust between offset spreading centers. Active transform faults, and abandoned transform structures left in their wakes, show features that reflect different amounts (and durations) of slip that can be viewed as a series of snapshots of different stages of transform fault evolution in thick, oceanic crust. This crust has a highly anisotropic, spreading fabric with pervasive zones of weakness created by spreading-related normal faults, fissures and dike margins oriented parallel to the spreading centers where they formed. These structures have a strong influence on the mechanical properties of the crust. By integrating available data, we suggest a series of stages of transform development: 1) Formation of an oblique rift (or leaky transform) with magmatic centers, linked by bookshelf fault zones (antithetic strike-slip faults at a high angle to the spreading direction) (Grimsey Fault Zone, youngest part of the TFZ); 2) broad zone of conjugate faulting (tens of km) (Hreppar Block N of the SISZ); 3) narrower ( 20 km) zone of bookshelf faulting aligned with the spreading direction (SISZ); 4) mature, narrow ( 1 km) through-going transform fault zone bounded by deformation (bookshelf faulting and block rotations) distributed over 10 km to either side (Húsavík-Flatey Fault Zone in the TFZ). With progressive slip, the transform zone becomes progressively narrower and more closely aligned with the spreading direction. The transform and non-transform (beyond spreading centers) domains may be truncated by renewed propagation and separated by subsequent spreading. This perspective

  10. Risk analysis of urban gas pipeline network based on improved bow-tie model

    Science.gov (United States)

    Hao, M. J.; You, Q. J.; Yue, Z.

    2017-11-01

    Gas pipeline network is a major hazard source in urban areas. In the event of an accident, there could be grave consequences. In order to understand more clearly the causes and consequences of gas pipeline network accidents, and to develop prevention and mitigation measures, the author puts forward the application of improved bow-tie model to analyze risks of urban gas pipeline network. The improved bow-tie model analyzes accident causes from four aspects: human, materials, environment and management; it also analyzes the consequences from four aspects: casualty, property loss, environment and society. Then it quantifies the causes and consequences. Risk identification, risk analysis, risk assessment, risk control, and risk management will be clearly shown in the model figures. Then it can suggest prevention and mitigation measures accordingly to help reduce accident rate of gas pipeline network. The results show that the whole process of an accident can be visually investigated using the bow-tie model. It can also provide reasons for and predict consequences of an unfortunate event. It is of great significance in order to analyze leakage failure of gas pipeline network.

  11. Upstream pressure variations associated with the bow shock and their effects on the magnetosphere

    International Nuclear Information System (INIS)

    Fairfield, D.H.; Baumjohann, W.; Paschmann, G.; Luehr, H.; Sibeck, D.G.

    1990-01-01

    Magnetic field enhancements and depressions on the time scales of minutes were frequently observed simultaneously by the AMPTE CCE, GOES 5, and GOES 6 spacecraft in the subsolar magnetosphere. The source of these perturbations has been detected in the high time resolution AMPTE IRM measurements of the kinetic pressure of the solar wind upstream of the bow shock. It is argued that these upstream pressure variations are not inherent in the solar wind but rather are associated with the bow shock. This conclusion follows from the facts that (1) the upstream field strength and the density associated with the perturbations are highly correlated with each other whereas these quantities tend to be anticorrelated in the undisturbed solar wind, and (2) the upstream perturbations occur within the foreshock or at its boundary. The results imply a mode of interaction between the solar wind and the magnetosphere whereby density changes produced in the foreshock subsequently convect through the bow shock and impinge on the magnetosphere. Also velocity decreases deep within the foreshock sometimes reach many tens of kilometers per second and may be associated with further pressure variations as a changing interplanetary field direction changes the foreshock geometry. Upstream pressure perturbations should create significant effects on the magnetopause and at the foot of nearby field lines that lead to the polar cusp ionosphere

  12. Upstream region, foreshock and bow shock wave at Halley's Comet from plasma electron measurements

    International Nuclear Information System (INIS)

    Anderson, K.A.; Carlson, C.W.; Curtis, D.W.

    1986-01-01

    Halley plasma electron parameters from 2.7 million km from the comet nucleus to the bow shock wave at 1.1 million km and beyond are surveyed. The features of the electron foreshock lying outside the shock to a distance of 230,000 km are described. It is a region of intense solar wind-comet plasma interaction in which energetic electrons are prominent. Several spikes of electrons whose energies extend to 2.5 keV appear in front of the shock. These energetic electrons may be accelerated in the same way electrons are accelerated at the Earth's bow shock to energies of 1 to 10 keV. The direction of the electron bulk flow direction changes abruptly between 1920 and 1922 UT, and the flow speed begins a sharp decline at the same time. It is suggested that the spacecraft entered the bow shock wave between 1920 and 1922 UT. Electron density variations at Halley are very much smaller than those at Giacobini-Zinner

  13. Interaction of single-pulse laser energy with bow shock in hypersonic flow

    Directory of Open Access Journals (Sweden)

    Hong Yanji

    2014-04-01

    Full Text Available Pressure sensing and schlieren imaging with high resolution and sensitivity are applied to the study of the interaction of single-pulse laser energy with bow shock at Mach 5. An Nd:YAG laser operated at 1.06 μm, 100 mJ pulse energy is used to break down the hypersonic flow in a shock tunnel. Three-dimensional Navier–Stokes equations are solved with an upwind scheme to simulate the interaction. The pressure at the stagnation point on the blunt body is measured and calculated to examine the pressure variation during the interaction. Schlieren imaging is used in conjunction with the calculated density gradients to examine the process of the interaction. The results show that the experimental pressure at the stagnation point on the blunt body and schlieren imaging fit well with the simulation. The pressure at the stagnation point on the blunt body will increase when the transmission shock approaches the blunt body and decrease with the formation of the rarefied wave. Bow shock is deformed during the interaction. Quasi-stationary waves are formed by high rate laser energy deposition to control the bow shock. The pressure and temperature at the stagnation point on the blunt body and the wave drag are reduced to 50%, 75% and 81% respectively according to the simulation. Schlieren imaging has provided important information for the investigation of the mechanism of the interaction.

  14. Recoil and Vibration in an Archery Bow Equipped with a Multi-Rod Stabilizer

    Directory of Open Access Journals (Sweden)

    Igor Zaniewski

    2012-01-01

    Full Text Available The aim of this research is to create a mechanical and mathematical model of a multi-rod stabilizer for the sport archery bow and to analyze its capability to damp disagreeable recoil and vibration of the bow during internal ballistic motion. The research methods are based on the Euler-Bernoulli theory of beam bending, Lagrange equations of the second kind, the Cauchy problem, and the Runge-Kutta method. A mathematical software package was used to analyze the problem. The approach to the problem of sport-bow stabilization in the vertical plane that is proposed in this paper addresses the practical needs both of applied engineering mechanics and of the sport of archery. Numerical results from computer simulation are presented in both tabular and graphical form. The common motion of the string and arrow (internal ballistic motion is accompanied by intense vibration which is caused by disruption of the static force balance at the moment of string release.

  15. PSR J2124-3358: A Bow Shock Nebula with an X-ray Tail

    Science.gov (United States)

    Chatterjee, S.; Gaensler, B. M.; Vigelius, M.; Cordes, J. M.; Arzoumanian, Z.; Stappers, B.; Ghavamian, P.; Melatos, A.

    2005-12-01

    As neutron stars move supersonically through the interstellar medium, their relativistic winds are confined by the ram pressure of the interstellar medium. The outer shocked layers may emit in Hα , producing a visible bow shock nebula, while the confined relativistic wind may produce radio or X-ray emission. The Hα bow shock nebula powered by the recycled pulsar J2124-3358 is asymmetric about the velocity vector and shows a marked kink. In recent observations with the Chandra X-ray Observatory, we have detected a long, curved X-ray tail associated with the pulsar. The tail is not aligned with the pulsar velocity, but is confined within the optical bow shock. The X-ray spectrum of the tail is well-fit by a power law, consistent with synchrotron emission from the wind termination shock and the post-shock flow. The presence of Hα and X-ray emission allows us to trace both the external ambient medium and the confined wind. In magnetohydrodynamic simulations, we verify that a bulk flow and non-uniformities in the ambient medium can produce the observed shape of the nebula, possibly in combination with an anisotropic pulsar wind. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO5-6075X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.

  16. New test of bow-shock models of Herbig-Haro objects

    International Nuclear Information System (INIS)

    Raga, A.C.; Bohm, K.H.; Solf, J.; Max-Planck-Institut fuer Astronomie, Heidelberg, West Germany)

    1986-01-01

    Long-slit, high-resolution spectroscopy of the Herbig-Haro oject HH 32 has shown that the emission-line profiles in all four condensations A, B, C, and D show high- and low-velocity components. The spatial maxima of these two components are always arranged in a double-layer pattern, with the maximum of the high-velocity component 0.6-1.0 arcsecs closer to the central star (AS 353A) than the low-velocity maximum. A study of the emission-line profiles predicted from a model of a radiating bow shock shows that such a double-layer structure appears naturally for this type of flow. In this case both the high-velocity and the low-velocity components come from the post-shock gas, in agreement with the theoretical prediction that it should be very difficult to detect the pre-shock gas observationally. The present results agree qualitatively well with observations of HH 32, strengthening the case for a bow-shock interpretation of this Herbig-Haro object. It is shown that the double-layer effect will be more easily observable for bow shocks which move at a relatively large angle with respect to the plane of the sky (i.e., for Herbig-Haro objects which have large radial velocities). 31 references

  17. Fault tree analysis

    International Nuclear Information System (INIS)

    1981-09-01

    Suggestion are made concerning the method of the fault tree analysis, the use of certain symbols in the examination of system failures. This purpose of the fault free analysis is to find logical connections of component or subsystem failures leading to undesirable occurrances. The results of these examinations are part of the system assessment concerning operation and safety. The objectives of the analysis are: systematical identification of all possible failure combinations (causes) leading to a specific undesirable occurrance, finding of reliability parameters such as frequency of failure combinations, frequency of the undesirable occurrance or non-availability of the system when required. The fault tree analysis provides a near and reconstructable documentation of the examination. (orig./HP) [de

  18. Deformation patterns in the southwestern part of the Mediterranean Ridge (South Matapan Trench, Western Greece)

    Science.gov (United States)

    Andronikidis, Nikolaos; Kokinou, Eleni; Vafidis, Antonios; Kamberis, Evangelos; Manoutsoglou, Emmanouil

    2017-12-01

    Seismic reflection data and bathymetry analyses, together with geological information, are combined in the present work to identify seabed structural deformation and crustal structure in the Western Mediterranean Ridge (the backstop and the South Matapan Trench). As a first step, we apply bathymetric data and state of art methods of pattern recognition to automatically detect seabed lineaments, which are possibly related to the presence of tectonic structures (faults). The resulting pattern is tied to seismic reflection data, further assisting in the construction of a stratigraphic and structural model for this part of the Mediterranean Ridge. Structural elements and stratigraphic units in the final model are estimated based on: (a) the detected lineaments on the seabed, (b) the distribution of the interval velocities and the presence of velocity inversions, (c) the continuity and the amplitudes of the seismic reflections, the seismic structure of the units and (d) well and stratigraphic data as well as the main tectonic structures from the nearest onshore areas. Seabed morphology in the study area is probably related with the past and recent tectonics movements that result from African and European plates' convergence. Backthrusts and reverse faults, flower structures and deep normal faults are among the most important extensional/compressional structures interpreted in the study area.

  19. Computer hardware fault administration

    Science.gov (United States)

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-09-14

    Computer hardware fault administration carried out in a parallel computer, where the parallel computer includes a plurality of compute nodes. The compute nodes are coupled for data communications by at least two independent data communications networks, where each data communications network includes data communications links connected to the compute nodes. Typical embodiments carry out hardware fault administration by identifying a location of a defective link in the first data communications network of the parallel computer and routing communications data around the defective link through the second data communications network of the parallel computer.

  20. Fault Tolerant Computer Architecture

    CERN Document Server

    Sorin, Daniel

    2009-01-01

    For many years, most computer architects have pursued one primary goal: performance. Architects have translated the ever-increasing abundance of ever-faster transistors provided by Moore's law into remarkable increases in performance. Recently, however, the bounty provided by Moore's law has been accompanied by several challenges that have arisen as devices have become smaller, including a decrease in dependability due to physical faults. In this book, we focus on the dependability challenge and the fault tolerance solutions that architects are developing to overcome it. The two main purposes

  1. Fault tolerant linear actuator

    Science.gov (United States)

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  2. Three dimensional investigation on the oceanic active fault. A demonstration survey

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Seizo; Kishimoto, Kiyoyuki; Okamoto, Yukinobu; Ikehara, Ken; Kuramoto, Shinichi; Sato, Mikio; Arai, Kosaku [Geological Survey of Japan, Tsukuba, Ibaraki (Japan)

    2000-02-01

    In order to upgrade activity and likelihood ratio on active potential evaluation of the water active fault with possibility of severe effect on nuclear facilities, by generally applying the conventional procedures to some areas and carrying out a demonstration survey, a qualitative upgrading on survey to be conducted by the executives was planned. In 1998 fiscal year, among the water active faults classified to the trench and the inland types, three dimensional survey on the inland type water active fault. The survey was carried out at the most southern part of aftershock area in the 1983 Nihonkai-Chubu earthquake, which is understood to be a place changing shallow geological structure (propagation of fault) from an old report using the sonic survey. As a result, a geological structure thought to be an active fault at a foot of two ridge topographies was found. Each fault was thought to be a reverse fault tilt to its opposite direction and an active fault cutting to its sea bottom. (G.K.)

  3. Three dimensional investigation on the oceanic active fault. A demonstration survey

    International Nuclear Information System (INIS)

    Nakao, Seizo; Kishimoto, Kiyoyuki; Okamoto, Yukinobu; Ikehara, Ken; Kuramoto, Shinichi; Sato, Mikio; Arai, Kosaku

    2000-01-01

    In order to upgrade activity and likelihood ratio on active potential evaluation of the water active fault with possibility of severe effect on nuclear facilities, by generally applying the conventional procedures to some areas and carrying out a demonstration survey, a qualitative upgrading on survey to be conducted by the executives was planned. In 1998 fiscal year, among the water active faults classified to the trench and the inland types, three dimensional survey on the inland type water active fault. The survey was carried out at the most southern part of aftershock area in the 1983 Nihonkai-Chubu earthquake, which is understood to be a place changing shallow geological structure (propagation of fault) from an old report using the sonic survey. As a result, a geological structure thought to be an active fault at a foot of two ridge topographies was found. Each fault was thought to be a reverse fault tilt to its opposite direction and an active fault cutting to its sea bottom. (G.K.)

  4. Wind turbine fault detection and fault tolerant control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Johnson, Kathryn

    2013-01-01

    In this updated edition of a previous wind turbine fault detection and fault tolerant control challenge, we present a more sophisticated wind turbine model and updated fault scenarios to enhance the realism of the challenge and therefore the value of the solutions. This paper describes...

  5. Oceanic Lithosphere Magnetization: Marine Magnetic Investigations of Crustal Accretion and Tectonic Processes in Mid-Ocean Ridge Environments

    Science.gov (United States)

    2007-09-01

    9’ 25’N on the EPR, along the northern section of the ridge bounded by the Clipperton and Siqueiros Transform Faults (TF) (Fig. 2-la). As with other...and encompasses the entire segment of the EPR from the Clipperton TF to the Siqueiros TF. The Carbotte and Macdonald [ 1992] grid was continued...al. [1996], Nicolas et al. [1996]; Kelemen et al.[1997]; Le Mee et al. [2004]), Bay of Islands ophiolite (Canada) [Swift and Johnson, 1984] and

  6. The San Andreas Fault and a Strike-slip Fault on Europa

    Science.gov (United States)

    1998-01-01

    The mosaic on the right of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, the size of the California portion of the San Andreas fault on Earth which runs from the California-Mexico border north to the San Francisco Bay. The left mosaic shows the portion of the San Andreas fault near California's san Francisco Bay that has been scaled to the same size and resolution as the Europa image. Each covers an area approximately 170 by 193 kilometers(105 by 120 miles). The red line marks the once active central crack of the Europan fault (right) and the line of the San Andreas fault (left). A strike-slip fault is one in which two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. The overall motion along the Europan fault seems to have followed a continuous narrow crack along the entire length of the feature, with a path resembling stepson a staircase crossing zones which have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. Opposite sides of the fault can be reconstructed like a puzzle, matching the shape of the sides as well as older individual cracks and ridges that had been broken by its movements. Bends in the Europan fault have allowed the surface to be pulled apart. This pulling-apart along the fault's bends created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, and in Death Valley and the Dead Sea. In those cases, the pulled apart regions can include upwelled materials, but may

  7. The gas-hydrate-related seabed features in the Palm Ridge off southwest Taiwan

    Science.gov (United States)

    Su, Zheng-Wei; Hsu, Shu-Kun; Tsai, Ching-Hui; Chen, Song-Chuen; Lin, Hsiao-Shan

    2016-04-01

    The offshore area of the SW Taiwan is located in the convergence zone between the northern continental margin of the South China Sea and the Manila subduction complex. Our study area, the Palm Ridge, is located in the passive continental margin. According to the geophysical, geochemical and geothermal data, abundant gas hydrate may exist in the offshore area of SW Taiwan. In this study, we will study the relation between the seabed features and the gas hydrate formation of the Palm Ridge. The data used in this study include high-resolution sidescan sonar images, sub-bottom profiles, echo sounder system, multi-beam bathymetric data, multi-channel reflection seismic and submarine photography in the Palm Ridge. Our results show the existing authigenic carbonates, gas seepages and gas plumes are mainly distributed in the bathymetric high of the Palm Ridge. Numerous submarine landslides have occurred in the place where the BSR distribution is not continuous. We suggest that it may be because of rapid slope failure, causing the change of the gas hydrate stability zone. We also found several faults on the R3.1 anticline structure east of the deformation front. These features imply that abundant deep methane gases have migrated to shallow strata, causing submarine landslides or collapse. The detailed relationship of gas migration and submarine landslides need further studies.

  8. Fault management and systems knowledge

    Science.gov (United States)

    2016-12-01

    Pilots are asked to manage faults during flight operations. This leads to the training question of the type and depth of system knowledge required to respond to these faults. Based on discussions with multiple airline operators, there is agreement th...

  9. ESR dating of fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon

    2002-03-01

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene

  10. Fault diagnosis of induction motors

    CERN Document Server

    Faiz, Jawad; Joksimović, Gojko

    2017-01-01

    This book is a comprehensive, structural approach to fault diagnosis strategy. The different fault types, signal processing techniques, and loss characterisation are addressed in the book. This is essential reading for work with induction motors for transportation and energy.

  11. ESR dating of fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2002-03-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene.

  12. Dynamics of intraoceanic subduction initiation : 1. Oceanic detachment fault inversion and the formation of supra-subduction zone ophiolites

    NARCIS (Netherlands)

    Maffione, Marco; Thieulot, Cedric; van Hinsbergen, Douwe J.J.; Morris, Antony; Plümper, Oliver; Spakman, Wim

    Subduction initiation is a critical link in the plate tectonic cycle. Intraoceanic subduction zones can form along transform faults and fracture zones, but how subduction nucleates parallel to mid-ocean ridges, as in e.g., the Neotethys Ocean during the Jurassic, remains a matter of debate. In

  13. Introduction to fault tree analysis

    International Nuclear Information System (INIS)

    Barlow, R.E.; Lambert, H.E.

    1975-01-01

    An elementary, engineering oriented introduction to fault tree analysis is presented. The basic concepts, techniques and applications of fault tree analysis, FTA, are described. The two major steps of FTA are identified as (1) the construction of the fault tree and (2) its evaluation. The evaluation of the fault tree can be qualitative or quantitative depending upon the scope, extensiveness and use of the analysis. The advantages, limitations and usefulness of FTA are discussed

  14. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    In the recent years the wind turbine industry has focused on optimizing the cost of energy. One of the important factors in this is to increase reliability of the wind turbines. Advanced fault detection, isolation and accommodation are important tools in this process. Clearly most faults are deal...... scenarios. This benchmark model is used in an international competition dealing with Wind Farm fault detection and isolation and fault tolerant control....

  15. Deformed Fluvial Terraces of Little Rock Creek Capture Off-Fault Strain Adjacent to the Mojave Section of the San Andreas Fault

    Science.gov (United States)

    Moulin, A.; Scharer, K. M.; Cowgill, E.

    2017-12-01

    Examining discrepancies between geodetic and geomorphic slip-rates along major strike-slip faults is essential for understanding both fault behavior and seismic hazard. Recent work on major strike-slip faults has highlighted off-fault deformation and its potential impact on fault slip rates. However, the extent of off-fault deformation along the San Andreas Fault (SAF) remains largely uncharacterized. Along the Mojave section of the SAF, Little Rock Creek drains from south to north across the fault and has cut into alluvial terraces abandoned between 15 and 30 ka1. The surfaces offer a rare opportunity to both characterize how right-lateral slip has accumulated along the SAF over hundreds of seismic cycles, and investigate potential off-fault deformation along secondary structures, where strain accumulates at slower rates. Here we use both field observations and DEM analysis of B4 lidar data to map alluvial and tectonic features, including 9 terrace treads that stand up to 80 m above the modern channel. We interpret the abandonment and preservation of the fluvial terraces to result from episodic capture of Little Rock Creek through gaps in a shutter ridge north of the fault, followed by progressive right deflection of the river course during dextral slip along the SAF. Piercing lines defined by fluvial terrace risers suggest that the amount of right slip since riser formation ranges from 400m for the 15-ka-riser to 1200m for the 30-ka-riser. Where they are best-preserved NE of the SAF, terraces are also cut by NE-facing scarps that trend parallel to the SAF in a zone extending up to 2km from the main fault. Exposures indicate these are fault scarps, with both reverse and normal stratigraphic separation. Geomorphic mapping reveals deflections of both channel and terrace risers (up to 20m) along some of those faults suggesting they could have accommodated a component of right-lateral slip. We estimated the maximum total amount of strike-slip motion recorded by the

  16. Row fault detection system

    Science.gov (United States)

    Archer, Charles Jens [Rochester, MN; Pinnow, Kurt Walter [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian Edward [Rochester, MN

    2008-10-14

    An apparatus, program product and method checks for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

  17. Fault isolation techniques

    Science.gov (United States)

    Dumas, A.

    1981-01-01

    Three major areas that are considered in the development of an overall maintenance scheme of computer equipment are described. The areas of concern related to fault isolation techniques are: the programmer (or user), company and its policies, and the manufacturer of the equipment.

  18. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S. A.

    This thesis considered the development of fault tolerant control systems. The focus was on the category of automated processes that do not necessarily comprise a high number of identical sensors and actuators to maintain safe operation, but still have a potential for improving immunity to component...

  19. Fault-Related Sanctuaries

    Science.gov (United States)

    Piccardi, L.

    2001-12-01

    Beyond the study of historical surface faulting events, this work investigates the possibility, in specific cases, of identifying pre-historical events whose memory survives in myths and legends. The myths of many famous sacred places of the ancient world contain relevant telluric references: "sacred" earthquakes, openings to the Underworld and/or chthonic dragons. Given the strong correspondence with local geological evidence, these myths may be considered as describing natural phenomena. It has been possible in this way to shed light on the geologic origin of famous myths (Piccardi, 1999, 2000 and 2001). Interdisciplinary researches reveal that the origin of several ancient sanctuaries may be linked in particular to peculiar geological phenomena observed on local active faults (like ground shaking and coseismic surface ruptures, gas and flames emissions, strong underground rumours). In many of these sanctuaries the sacred area is laid directly above the active fault. In a few cases, faulting has affected also the archaeological relics, right through the main temple (e.g. Delphi, Cnidus, Hierapolis of Phrygia). As such, the arrangement of the cult site and content of relative myths suggest that specific points along the trace of active faults have been noticed in the past and worshiped as special `sacred' places, most likely interpreted as Hades' Doors. The mythological stratification of most of these sanctuaries dates back to prehistory, and points to a common derivation from the cult of the Mother Goddess (the Lady of the Doors), which was largely widespread since at least 25000 BC. The cult itself was later reconverted into various different divinities, while the `sacred doors' of the Great Goddess and/or the dragons (offspring of Mother Earth and generally regarded as Keepers of the Doors) persisted in more recent mythologies. Piccardi L., 1999: The "Footprints" of the Archangel: Evidence of Early-Medieval Surface Faulting at Monte Sant'Angelo (Gargano, Italy

  20. Geology of the Syncline Ridge area related to nuclear waste disposal, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    Hoover, D.L.; Morrison, J.N.

    1980-01-01

    The Syncline Ridge area is in the western part of Yucca Flat, Nye Co., Nev. Drill holes, geophysical surveys, mapping, and laboratory studies during 1976 through 1978 were used to investigate argillite in unit J (Mississippian) of the Eleana Formation (Devonian and Mississippian) as a possible nuclear waste repository site. Argillite in unit J has a minimum stratigraphic thickness of at least 700 m. The argillite underlies most of the Syncline Ridge area east of the Eleana Range, and is overlain by Quaternary alluvium and the Tippipah Limestone of Syncline Ridge. At the edges of the Syncline Ridge area, alluvium and volcanic rocks overlie the argillite. The argillite is underlain by more than 1000 m of quartzite, siliceous argillite, and minor limestone in older units of the Eleana Formation. These older units crop out in the Eleana Range. The area is divided into southern, central, and northern structural blocks by two lateral faults. The southern and central blocks either have volumes of argillite too small for a repository site, or have irregular-shaped volumes caused by Mesozoic high-angle faults that make the structure too complex for a repository site. The northern block appears to contain thick argillite within an area of 6 to 8 km 2 . The postvolcanic history of the Syncline Ridge area indicates that the area has undergone less deformation than other areas in Yucca Flat. Most of the late Tertiary and Quaternary deformation consisted of uplift and eastward tilting in the Syncline Ridge area. Preliminary engineering geology investigations indicate that although the competency of the argillite is low, the argillite may be feasible for construction of a nuclear waste disposal facility. Physical, thermal, chemical, and mineralogical properties of the argillite appear to be within acceptable limits for a nuclear waste repository

  1. Martian Bow Shock and Magnetic Pile-Up Barrier Formation Due to the Exosphere Ion Mass-Loading

    Directory of Open Access Journals (Sweden)

    Eojin Kim

    2011-03-01

    Full Text Available Bow shock, formed by the interaction between the solar wind and a planet, is generated in different patterns depending on the conditions of the planet. In the case of the earth, its own strong magnetic field plays a critical role in determining the position of the bow shock. However, in the case of Mars of which has very a small intrinsic magnetic field, the bow shock is formed by the direct interaction between the solar wind and the Martian ionosphere. It is known that the position of the Martian bow shock is affected by the mass loading-effect by which the supersonic solar wind velocity becomes subsonic as the heavy ions originating from the planet are loaded on the solar wind. We simulated the Martian magnetosphere depending on the changes of the density and velocity of the solar wind by using the three-dimensional magnetohydrodynamic model built by modifying the comet code that includes the mass loading effect. The Martian exosphere model of was employed as the Martian atmosphere model, and only the photoionization by the solar radiation was considered in the ionization process of the neutral atmosphere. In the simulation result under the normal solar wind conditions, the Martian bow shock position in the subsolar point direction was consistent with the result of the previous studies. The three-dimensional simulation results produced by varying the solar wind density and velocity were all included in the range of the Martian bow shock position observed by Mariner 4, Mars 2, 3, 5, and Phobos 2. Additionally, the simulation result also showed that the change of the solar wind density had a greater effect on the Martian bow shock position than the change of the solar wind velocity. Our result may be useful in analyzing the future observation data by Martian probes.

  2. LAMPF first-fault identifier for fast transient faults

    International Nuclear Information System (INIS)

    Swanson, A.R.; Hill, R.E.

    1979-01-01

    The LAMPF accelerator is presently producing 800-MeV proton beams at 0.5 mA average current. Machine protection for such a high-intensity accelerator requires a fast shutdown mechanism, which can turn off the beam within a few microseconds of the occurrence of a machine fault. The resulting beam unloading transients cause the rf systems to exceed control loop tolerances and consequently generate multiple fault indications for identification by the control computer. The problem is to isolate the primary fault or cause of beam shutdown while disregarding as many as 50 secondary fault indications that occur as a result of beam shutdown. The LAMPF First-Fault Identifier (FFI) for fast transient faults is operational and has proven capable of first-fault identification. The FFI design utilized features of the Fast Protection System that were previously implemented for beam chopping and rf power conservation. No software changes were required

  3. Oak Ridge rf Test Facility

    International Nuclear Information System (INIS)

    Gardner, W.L.; Hoffman, D.J.; McCurdy, H.C.; McManamy, T.J.; Moeller, J.A.; Ryan, P.M.

    1985-01-01

    The rf Test Facility (RFTF) of Oak Ridge National Laboratory (ORNL) provides a national facility for the testing and evaluation of steady-state, high-power (approx.1.0-MW) ion cyclotron resonance heating (ICRH) systems and components. The facility consists of a vacuum vessel and two fully tested superconducting development magnets from the ELMO Bumpy Torus Proof-of-Principle (EBT-P) program. These are arranged as a simple mirror with a mirror ratio of 4.8. The axial centerline distance between magnet throat centers is 112 cm. The vacuum vessel cavity has a large port (74 by 163 cm) and a test volume adequate for testing prototypic launchers for Doublet III-D (DIII-D), Tore Supra, and the Tokamak Fusion Test Reactor (TFTR). Attached to the internal vessel walls are water-cooled panels for removing the injected rf power. The magnets are capable of generating a steady-state field of approx.3 T on axis in the magnet throats. Steady-state plasmas are generated in the facility by cyclotron resonance breakdown using a dedicated 200-kW, 28-GHz gyrotron. Available rf sources cover a frequency range of 2 to 200 MHz at 1.5 kW and 3 to 18 MHz at 200 kW, with several sources at intermediate parameters. Available in July 1986 will be a >1.0-MW, cw source spanning 40 to 80 MHz. 5 figs

  4. Sepentinized Peridotite Spinel Composition: Northern Central Indian Ridge at 6°39

    Science.gov (United States)

    Ray, D.; Banerjee, R.; Iyer, S. D.; Balaram, V.; Speakman, J.

    2005-12-01

    Exposures of serpentinized peridotites on the seafloor at slow-spreading ridges have been interpreted either as accretion of ridge segments in a magma-starved condition along the non-transform setting or as preferential outcrops at ridge offsets in transform fault setting. Here we present the mineral chemistry and geochemistry of serpentinites and serpentinized spinel peridotites recovered from an off axis region (corner high) at south of Vityaz transform fault (6°39'S), Northern Central Indian Ridge. Our purpose is to use mineral chemical data of serpentine and spinel to investigate the effect of low temperature alteration processes and degree of partial melting. Serpentine composition shows presence of high Mg-rich lizardite and chrysotile pseudomorphs and these rocks mostly preserve `mesh rim', `window' and `hourglass' textures, representing extensive hydration during low temperature hydrothermal alteration. In thin section, serpentine veins (mainly lensoidal, pinch and swell or anastomosing) are common, sometime crosscutting the `mesh rim' textures to attest to the intensity of serpentinization process. In one sample, a 1.9 cm-thick feldspathic vein crosscut the serpentinite as a porphyroblast and this indicates discontinuity in magmatic crust caused due to less magma input at off-axis region facilitate the intrusion of short-living feeder dykes of highly fractionated late magmatic liquids within the peridotite. In addition, in hand specimen, presence of smaller-scale striations analogous to slickenlines on serpentinite surfaces suggests low-angle faulting, which could have enhanced pervasive serpentinization during their subsequent emplacement. Individual serpentine grain displays very low Ca content (0.01 wt%) suggesting possible absence of any secondary Ca-rich phases also verified by very low Sr content (connotation. Limited data on composition of individual spinel porphyroclast exhibits substantial variation in their Mg# (mole [Mg/ Mg+Fe2]) and Cr# (mole

  5. Magdalena Ridge Observatory Interferometer: Status Update

    National Research Council Canada - National Science Library

    Creech-Eakman, M. J; Bakker, E. J; Buscher, D. F; Coleman, T. A; Haniff, C. A; Jurgenson, C. A; Klinglesmith, III, D. A; Parameswariah, C. B; Romero, V. D; Shtromberg, A. V; Young, J. S

    2006-01-01

    The Magdalena Ridge Observatory Interferometer (MROI) is a ten element optical and near-infrared imaging interferometer being built in the Magdalena mountains west of Socorro, NM at an altitude of 3230 m...

  6. A deep structural ridge beneath central India

    Science.gov (United States)

    Agrawal, P. K.; Thakur, N. K.; Negi, J. G.

    A joint-inversion of magnetic satellite (MAGSAT) and free air gravity data has been conducted to quantitatively investigate the cause for Bouguer gravity anomaly over Central Indian plateaus and possible fold consequences beside Himalayan zone in the Indian sub-continent due to collision between Indian and Eurasian plates. The appropriate inversion with 40 km crustal depth model has delineated after discriminating high density and magnetisation models, for the first time, about 1500 km long hidden ridge structure trending NW-SE. The structure is parallel to Himalayan fold axis and the Indian Ocean ridge in the Arabian Sea. A quantitative relief model across a representative anomaly profile confirms the ridge structure with its highest point nearly 6 km higher than the surrounding crustal level in peninsular India. The ridge structure finds visible support from the astro-geoidal contours.

  7. Fault-tolerant computing systems

    International Nuclear Information System (INIS)

    Dal Cin, M.; Hohl, W.

    1991-01-01

    Tests, Diagnosis and Fault Treatment were chosen as the guiding themes of the conference. However, the scope of the conference included reliability, availability, safety and security issues in software and hardware systems as well. The sessions were organized for the conference which was completed by an industrial presentation: Keynote Address, Reconfiguration and Recover, System Level Diagnosis, Voting and Agreement, Testing, Fault-Tolerant Circuits, Array Testing, Modelling, Applied Fault Tolerance, Fault-Tolerant Arrays and Systems, Interconnection Networks, Fault-Tolerant Software. One paper has been indexed separately in the database. (orig./HP)

  8. Fault rocks and uranium mineralization

    International Nuclear Information System (INIS)

    Tong Hangshou.

    1991-01-01

    The types of fault rocks, microstructural characteristics of fault tectonite and their relationship with uranium mineralization in the uranium-productive granite area are discussed. According to the synthetic analysis on nature of stress, extent of crack and microstructural characteristics of fault rocks, they can be classified into five groups and sixteen subgroups. The author especially emphasizes the control of cataclasite group and fault breccia group over uranium mineralization in the uranium-productive granite area. It is considered that more effective study should be made on the macrostructure and microstructure of fault rocks. It is of an important practical significance in uranium exploration

  9. Network Fault Diagnosis Using DSM

    Institute of Scientific and Technical Information of China (English)

    Jiang Hao; Yan Pu-liu; Chen Xiao; Wu Jing

    2004-01-01

    Difference similitude matrix (DSM) is effective in reducing information system with its higher reduction rate and higher validity. We use DSM method to analyze the fault data of computer networks and obtain the fault diagnosis rules. Through discretizing the relative value of fault data, we get the information system of the fault data. DSM method reduces the information system and gets the diagnosis rules. The simulation with the actual scenario shows that the fault diagnosis based on DSM can obtain few and effective rules.

  10. San Andreas-sized Strike-slip Fault on Europa

    Science.gov (United States)

    1998-01-01

    This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay. In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements. [figure removed for brevity, see original site] The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart. Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above. One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension opens the fault and

  11. New Evidence for Quaternary Strain Partitioning Along the Queen Charlotte Fault System, Southeastern Alaska

    Science.gov (United States)

    Walton, M. A. L.; Miller, N. C.; Brothers, D. S.; Kluesner, J.; Haeussler, P. J.; Conrad, J. E.; Andrews, B. D.; Ten Brink, U. S.

    2017-12-01

    The Queen Charlotte Fault (QCF) is a fast-moving ( 53 mm/yr) transform plate boundary fault separating the Pacific Plate from the North American Plate along western Canada and southeastern Alaska. New high-resolution bathymetric data along the fault show that the QCF main trace accommodates nearly all strike-slip plate motion along a single narrow deformation zone, though questions remain about how and where smaller amounts of oblique convergence are accommodated along-strike. Obliquity and convergence rates are highest in the south, where the 2012 Haida Gwaii, British Columbia MW 7.8 thrust earthquake was likely caused by Pacific underthrusting. In the north, where obliquity is lower, aftershocks from the 2013 Craig, Alaska MW 7.5 strike-slip earthquake also indicate active convergent deformation on the Pacific (west) side of the plate boundary. Off-fault structures previously mapped in legacy crustal-scale seismic profiles may therefore be accommodating part of the lesser amounts of Quaternary convergence north of Haida Gwaii. Between 2015 and 2017, the USGS acquired more than 8,000 line-km of offshore high-resolution multichannel seismic (MCS) data along the QCF to better understand plate boundary deformation. The new MCS data show evidence for Quaternary deformation associated with a series of elongate ridges located within 30 km of the QCF main trace on the Pacific side. These ridges are anticlinal structures flanked by growth faults, with recent deformation and active fluid flow characterized by seafloor scarps and seabed gas seeps at ridge crests. Structural and morphological evidence for contractional deformation decreases northward along the fault, consistent with a decrease in Pacific-North America obliquity along the plate boundary. Preliminary interpretations suggest that plate boundary transpression may be partitioned into distinctive structural domains, in which convergent stress is accommodated by margin-parallel thrust faulting, folding, and ridge

  12. Oak Ridge Reservation environmental report for 1989

    International Nuclear Information System (INIS)

    Jacobs, V.A.; Wilson, A.R.

    1990-10-01

    This two-volume report, the Oak Ridge Reservation Environmental Report for 1989, is the nineteenth in an annual series that began in 1971. It reports the results of a comprehensive, year-round program to monitor the impact of operations at the three major US Department of Energy (DOE) production and research installations in Oak Ridge on the immediate areas' and surrounding region's groundwater and surface waters, soil, air quality, vegetation and wildlife, and through these multiple and varied pathways, the resident human population. Information is presented for the environmental monitoring Quality Assurance (QA) Program, audits and reviews, waste management activities, land special environmental studies. Data are included for the Oak Ridge Y-12 Plant, Oak Ridge National Laboratory (ORNL), and Oak Ridge Gaseous Diffusion Plant (ORGDP). Volume 1 presents narratives, summaries, and conclusions based on environmental monitoring at the three DOE installations and in the surrounding environs during calendar year (CY) 1989. Volume 1 is intended to be a ''stand-alone'' report about the Oak Ridge Reservation (ORR) for the reader who does not want an in-depth review of 1989 data. Volume 2 presents the detailed data from which these conclusions have been drawn and should be used in conjunction with Volume 1

  13. Oak Ridge Reservation environmental report for 1989

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, V.A.; Wilson, A.R. (eds.)

    1990-10-01

    This two-volume report, the Oak Ridge Reservation Environmental Report for 1989, is the nineteenth in an annual series that began in 1971. It reports the results of a comprehensive, year-round program to monitor the impact of operations at the three major US Department of Energy (DOE) production and research installations in Oak Ridge on the immediate areas' and surrounding region's groundwater and surface waters, soil, air quality, vegetation and wildlife, and through these multiple and varied pathways, the resident human population. Information is presented for the environmental monitoring Quality Assurance (QA) Program, audits and reviews, waste management activities, land special environmental studies. Data are included for the Oak Ridge Y-12 Plant, Oak Ridge National Laboratory (ORNL), and Oak Ridge Gaseous Diffusion Plant (ORGDP). Volume 1 presents narratives, summaries, and conclusions based on environmental monitoring at the three DOE installations and in the surrounding environs during calendar year (CY) 1989. Volume 1 is intended to be a stand-alone'' report about the Oak Ridge Reservation (ORR) for the reader who does not want an in-depth review of 1989 data. Volume 2 presents the detailed data from which these conclusions have been drawn and should be used in conjunction with Volume 1.

  14. Holocene and latest Pleistocene oblique dextral faulting on the southern Inyo Mountains fault, Owens Lake basin, California

    Science.gov (United States)

    Bacon, S.N.; Jayko, A.S.; McGeehin, J.P.

    2005-01-01

    The Inyo Mountains fault (IMF) is a more or less continuous range-front fault system, with discontinuous late Quaternary activity, at the western base of the Inyo Mountains in Owens Valley, California. The southern section of the IMF trends ???N20??-40?? W for at least 12 km at the base of and within the range front near Keeler in Owens Lake basin. The southern IMF cuts across a relict early Pliocene alluvial fan complex, which has formed shutter ridges and northeast-facing scarps, and which has dextrally offset, well-developed drainages indicating long-term activity. Numerous fault scarps along the mapped trace are northeast-facing, mountain-side down, and developed in both bedrock and younger alluvium, indicating latest Quaternary activity. Latest Quaternary multiple- and single-event scarps that cut alluvium range in height from 0.5 to 3.0 m. The penultimate event on the southern IMF is bracketed between 13,310 and 10,590 cal years B.P., based on radiocarbon dates from faulted alluvium and fissure-fill stratigraphy exposed in a natural wash cut. Evidence of the most recent event is found at many sites along the mapped fault, and, in particular, is seen in an ???0.5-m northeast-facing scarp and several right-stepping en echelon ???0.5-m-deep depressions that pond fine sediment on a younger than 13,310 cal years B.P. alluvial fan. A channel that crosses transverse to this scarp is dextrally offset 2.3 ?? 0.8 m, providing a poorly constrained oblique slip rate of 0.1-0. 3 m/ k.y. The identified tectonic geomorphology and sense of displacement demonstrate that the southern IMF accommodates predominately dextral slip and should be integrated into kinematic fault models of strain distribution in Owens Valley.

  15. New Seismic Monitoring Station at Mohawk Ridge, Valles Caldera

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Peter Morse [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-20

    Two new broadband digital seismic stations were installed in the Valles Caldera in 2011 and 2012. The first is located on the summit of Cerros del Abrigo (station code CDAB) and the second is located on the flanks of San Antonio Mountain (station code SAMT). Seismic monitoring stations in the caldera serve multiple purposes. These stations augment and expand the current coverage of the Los Alamos Seismic Network (LASN), which is operated to support seismic and volcanic hazards studies for LANL and northern New Mexico (Figure 1). They also provide unique continuous seismic data within the caldera that can be used for scientific studies of the caldera’s substructure and detection of very small seismic signals that may indicate changes in the current and evolving state of remnant magma that is known to exist beneath the caldera. Since the installation of CDAB and SAMT, several very small earthquakes have already been detected near San Antonio Mountain just west of SAMT (Figure 2). These are the first events to be seen in that area. Caldera stations also improve the detection and epicenter determination quality for larger local earthquakes on the Pajarito Fault System east of the Preserve and the Nacimiento Uplift to the west. These larger earthquakes are a concern to LANL Seismic Hazards assessments and seismic monitoring of the Los Alamos region, including the VCNP, is a DOE requirement. Currently the next closest seismic stations to the caldera are on Pipeline Road (PPR) just west of Los Alamos, and Peralta Ridge (PER) south of the caldera. There is no station coverage near the resurgent dome, Redondo Peak, in the center of the caldera. Filling this “hole” is the highest priority for the next new LASN station. We propose to install this station in 2018 on Mohawk Ridge just east of Redondito, in the same area already occupied by other scientific installations, such as the MCON flux tower operated by UNM.

  16. Observational test of shock drift and Fermi acceleration on a seed particle population upstream of earth's bow shock

    Science.gov (United States)

    Anagnostopoulos, G. C.; Sarris, E. T.; Krimigis, S. M.

    1988-01-01

    The efficiency of proposed shock acceleration mechanisms as they operate at the bow shock in the presence of a seed energetic particle population was examined using data from simultaneous observations of energetic solar-origin protons, carried out by the IMP 7 and 8 spacecraft in the vicinity of the quasi-parallel (dawn) and quasi-perpendicular (dusk) regions of the earth's bow shock, respectively. The results of observations (which include acceleration effects in the intensities of the energetic protons with energies as high as 4 MeV observed at the vicinity of the dusk bow shock, but no evidence for any particle acceleration at the energy equal to or above 50 keV at the dawn side of the bow shock) indicate that the acceleration of a seed particle population occurs only at the quasi-perpendicular bow shock through shock drift acceleration and that the major source of observed upstream ion populations is the leakage of magnetospheric ions of energies not less than 50 keV, rather than in situ acceleration.

  17. Ionospheric Bow Wave Induced by the Moon Shadow Ship Over the Continent of United States on 21 August 2017

    Science.gov (United States)

    Sun, Yang-Yi; Liu, Jann-Yenq; Lin, Charles Chien-Hung; Lin, Chi-Yen; Shen, Ming-Hsueh; Chen, Chieh-Hung; Chen, Chia-Hung; Chou, Min-Yang

    2018-01-01

    A moon shadow of the total solar eclipse swept through the continent of United States (CONUS) from west to east on 21 August 2017. Massive total electron content (integration of electron density from 0 km to 20,200 km altitude) observations from 2,255 ground-based Global Navigation Satellite System receivers show that the moon shadow ship generates a great ionospheric bow wave front which extends 1,500 km away from the totality path covering the entire CONUS. The bow wave front consists of the acoustic shock wave due to the supersonic/near-supersonic moon shadow ship and the significant plasma recombination due to the reduction in solar irradiation within the shadow area. The deep bow wave trough (-0.02 total electron content unit (1 TECU = 1016 el m-2) area) nearly coincides with the 100% obscuration moving along the totality path over the CONUS through the entire eclipse period. The supersonic moon shadow ship induces a bow wave crest in front of the ship ( 80% obscuration). It is the first time to find the acoustic shock wave-formed bow wave trough and crest near the totality.

  18. Thermal/hydraulic bowing stability analysis of grid-supported multi-pin bundles with differential swelling and irradiation creep

    International Nuclear Information System (INIS)

    McAreavey, G.

    1977-01-01

    Azimuthal variations of clad temperature in fuel pin bundles leads to pin bowing by differential thermal expansion. During irradiation in a fast flux further possibly more severe bowing is caused by differential neutron induced voidage swelling, which, being temperature sensitive, will also vary azimuthally. The problem of pin bowing in a fuel element cluster involves consideration of the thermal/hydraulic behaviour, allowing for both inherent and induced clad temperature non-uniformities, coupled with the restrained bowing behaviour, including differential thermal expansion, differential swelling, and irradiation creep. All pins must be considered simultaneously. In the temperature and stress ranges of interest thermal creep may be neglected. An existing computer code, IAMBIC solves the zero time thermal bowing problem for a cluster of up to 61 pins on hexagonal pitch, with up to 21 supports at arbitrary axial spacing. The present paper describes the basis of TRIAMBIC, a time dependent code which analyses the irradiation induced effects in fuel pin bunbles due to fast neutrons. (Auth.)

  19. On the failure behaviour to striking bow penetration of impacted marine-steel structures

    Science.gov (United States)

    Prabowo, Aditya Rio; Muttaqie, Teguh; Sohn, Jung Min; Bae, Dong Myung; Setiyawan, Agus

    2018-04-01

    Demands for water transportation modes are continuously increasing as rapid economic and industrial growths in the recent decade. Ship as representative of the water transportation is generally needed to carry various products from one location to another. Besides as product carrier, ship also acts as public facility to transport human across islands for number of reasons, such as tourism and vehicle. Considering its importance, structural damage due to accidental loads or so-called impact can cause unacceptable casualties which threat ship passenger, shipping industry and maritime environment in same time. The most frequent impact phenomena occur in forms of collision and grounding, which are targeting side structure and double bottom consecutively. However, since responses of the impacts on structure are highly nonlinear and vary due to development of ship structures, sustainable analysis as an update of pioneer calculation can be beneficial as rational reference for improving safety and navigational instruments. This work aims to assess failures of the side structures subjected to penetration of striking bow in ship-ship collision scenario. Locations of impact are idealized to happen on after-end, midsection and fore-end to provide complete assessment. Striking bow is to be deployed by varying input velocity to observe significance of the fractures on the side structure. This configuration is implemented on the designed collision scenario, and later calculated using nonlinear finite element method (NLFEM). Summary of the solution indicated that the midsection produced the highest resistance against side collision. Breaching of the inner shell was successfully avoided on the fore-end, but the critical damage to the cargo was observed during bow penetration to the after-end region. This location was recommended to be added by longitudinal framing to increase its resistance against ship collision.

  20. On the failure behaviour to striking bow penetration of impacted marine-steel structures

    Directory of Open Access Journals (Sweden)

    Prabowo Aditya Rio

    2018-04-01

    Full Text Available Demands for water transportation modes are continuously increasing as rapid economic and industrial growths in the recent decade. Ship as representative of the water transportation is generally needed to carry various products from one location to another. Besides as product carrier, ship also acts as public facility to transport human across islands for number of reasons, such as tourism and vehicle. Considering its importance, structural damage due to accidental loads or so-called impact can cause unacceptable casualties which threat ship passenger, shipping industry and maritime environment in same time. The most frequent impact phenomena occur in forms of collision and grounding, which are targeting side structure and double bottom consecutively. However, since responses of the impacts on structure are highly nonlinear and vary due to development of ship structures, sustainable analysis as an update of pioneer calculation can be beneficial as rational reference for improving safety and navigational instruments. This work aims to assess failures of the side structures subjected to penetration of striking bow in ship-ship collision scenario. Locations of impact are idealized to happen on after-end, midsection and fore-end to provide complete assessment. Striking bow is to be deployed by varying input velocity to observe significance of the fractures on the side structure. This configuration is implemented on the designed collision scenario, and later calculated using nonlinear finite element method (NLFEM. Summary of the solution indicated that the midsection produced the highest resistance against side collision. Breaching of the inner shell was successfully avoided on the fore-end, but the critical damage to the cargo was observed during bow penetration to the after-end region. This location was recommended to be added by longitudinal framing to increase its resistance against ship collision.

  1. Plasma electron signature of magnetic connection to the earth's bow shock: ISEE 3

    International Nuclear Information System (INIS)

    Feldman, W.C.; Anderson, R.C.; Asbridge, J.R.; Bame, S.J.; Gosling, J.T.; Zwickl, R.D.

    1982-01-01

    Enhanced fluxes of low-energy electrons backstreaming from the earth's bow shock have been identified at ISEE 3. When present, these fluxes modify ambient solar wind electron velocity distributions f(v) in characteristic ways that depends on whether ISEE 3 is near the edge, or within the interior of the earth's electron foreshock. Near the edge, energy peaks in f(v) are observed. Such distributions should be locally unstable to electron plasma oscillations. Well within the interior of the foreshock, enhanced fluxes of electrons with energies up to the maximum detected by the Los Alamos electron analyzer (approx.1 keV) are observed over the full backward hemisphere. These electrons can be modelled with an asymptotic power law distribution having index in the range 4< or approx. =p/sub b/s< or approx. =6. At intermediate energies (approx.20--50 eV), twin angular peaks are observed centered on the magnetic field direction B. Also observed at these times are depressions in f(v) at energies less than approx.20 eV that are centered on B. Such distributions having a perpendicular temperature greater than their parallel temperature may be locally unstable to the generation of whistler waves. Analysis of a particularly clean example of connection to the bow shock is consistent with the possiblility that the observed electron fluxes emerge from the forward foot of the electron heating region within bow shock where the electron density and temperature are larger than that of the uperturbed upstream solar wind by a factor of approx.1.2. This analysis also indicates that the electrostatic potential within the forward foot of the shock is between approx.5 and 50 V more positive than that within plasma far upstream at ISEE 3. However, these interpretations depend on the assumption of nearly scatter-free propagation, which may not hold

  2. Anomalous band-gap bowing of AlN1−xPx alloy

    International Nuclear Information System (INIS)

    Winiarski, M.J.; Polak, M.; Scharoch, P.

    2013-01-01

    Highlights: •Structural and electronic properties of AlN 1−x P x from first principles. •The supercell and the virtual crystall approximation methods applied and compared. •Anomalously high band-gap bowing found. •Similarities of band-gap behavior to that in BN 1−x P x noticed. •Performance of MBJLDA with the pseudopotential approach discussed. -- Abstract: Electronic structure of zinc blende AlN 1−x P x alloy has been calculated from first principles. Structural optimization has been performed within the framework of LDA and the band-gaps calculated with the modified Becke–Jonson (MBJLDA) method. Two approaches have been examined: the virtual crystal approximation (VCA) and the supercell-based calculations (SC). The composition dependence of the lattice parameter obtained from the SC obeys Vegard’s law whereas the volume optimization in the VCA leads to an anomalous bowing of the lattice constant. A strong correlation between the band-gaps and the structural parameter in the VCA method has been observed. On the other hand, in the SC method the supercell size and atoms arrangement (clustered vs. uniform) appear to have a great influence on the computed band-gaps. In particular, an anomalously big band-gap bowing has been found in the case of a clustered configuration with relaxed geometry. Based on the performed tests and obtained results some general features of MBJLDA are discussed and its performance for similar systems predicted

  3. Reflection of the solar wind ions at the earth's bow shock: energization

    International Nuclear Information System (INIS)

    Bonifazi, C.; Moreno, G.; Russell, C.T.

    1983-01-01

    The energies of the field-aligned proton beams observed upstream of the earth's bow shock are tested, on a statistical basis, against a simple reflection model. The comparison is carried out using both plasma and magnetic field data collected by the ISEE 2 spacecraft. The observations refer to the period from November 5 to December 20, 1977. According to this model, some of the solar wind protons incident upon the earth's shock front when reflected upstream gain energy by displacement parallel to the interplanetary electric field. The energy gained in the reflection can be described as a function of the angles between the interplanetary magnetic field, the solar wind bulk velocity, and the local shock normal. The task of finding these angles, i.e., the expected source point of the reflected ions at the earth's shock front, has been resolved using both the measured magnetic field direction and actual beam trajectory. The latter method, which takes into account the ion drift velocity, leads to a better agreement between theory and observations when far from the shock. In particular, it allows us to check the energies of the field-aligned beams even when they are observed far from the earth's bow shock (at distances up to 10-15 R/sub E/). We confirm, on a statistical basis, the test of the model recently carried out using the Los Alamos National Laboratory/Max-Planck-extraterrestrische observations on ISEE 1 and 2. We infer that reflected beams can sometimes propagate far upstream of the earth's bow shock without changing their energy properties

  4. Astrophysically relevant radiatively cooled hypersonic bow shocks in nested wire arrays

    Science.gov (United States)

    Ampleford, David

    2009-11-01

    We have performed laboratory experiments which introduce obstructions into hypersonic plasma flows to study the formation of shocks. Astrophysical observations have demonstrated many examples of equivalent radiatively cooled bow shocks, for example the head of protostellar jets or supernova remnants passing through the interstellar medium or between discrete clumps in jets. Wire array z-pinches allow us to study quasi-planar radiatively cooled flows in the laboratory. The early stage of a wire array z-pinch implosion consists of a steady flow of the wire material towards the axis. Given a high rate of radiative cooling, these flows reach high sonic- Mach numbers, typically up to 5. The 2D nature of this configuration allows the insertion of obstacles into the flow, such as a concentric ``inner'' wire array, as has previously been studied for ICF research. Here we study the application of such a nested array to laboratory astrophysics where the inner wires act as obstructions perpendicular to the flow, and induce bow shocks. By varying the wire array material (W/Al), the significance of radiative cooling on these shocks can be controlled, and is shown to change the shock opening angle. As multiple obstructions are present, the experiments show the interaction of multiple bow shocks. It is also possible to introduce a magnetic field around the static object, increasing the opening angle of the shocks. Further experiments can be designed to control the flow density, magnetic field structure and obstruction locations. In collaboration with: S.V. Lebedev, M.E. Cuneo, C.A. Jennings, S.N. Bland, J.P. Chittenden, A. Ciardi, G.N. Hall, S.C. Bott, M. Sherlock, A. Frank, E. Blackman

  5. Survey of coherent ion reflection at the quasi-parallel bow shock

    International Nuclear Information System (INIS)

    Onsager, T.G.; Thomsen, M.F.; Gosling, J.T.; Bame, S.J.; Russell, C.T.

    1990-01-01

    Ions coherently reflected off the Earth's bow shock have previously been observed both when the upstream geometry is quasi-perpendicular and when it is quasi-parallel. In the case of quasiperpendicular geometry, the ions are reflected in a nearly specular manner and are quickly carried back into the shock by the convecting magnetic field. In the quasi-parallel geometry, however, near-specularly reflected ions' guiding center velocities would on the average be directed away from the shock, allowing the ions to escape into the upstream region. The conditions under which coherent reflection occurs and the subsequent coupling of the reflected ions to the incoming solar wind plasma are important factors when assessing the contribution of the reflected ions to the downstream temperature increase and the shock structure. The survey presented in this paper, along with previously reported observations, suggests that near-specularly reflected ions are indeed an important aspect of energy dissipation at the Earth's quasi-parallel bow shock. The authors find that (1) cool, coherent, near-specularly reflected ion beams are detected over nearly the full range of upstream plasma paraameters commonly found at the Earth's bow shock; (2) the beams are typically observed only near the shock ramp or some shock-like feature; and (3) the observed beam velocities are almost always consistent with what one would expect for near-specularly reflected ions after only a small fraction of a gyroperiod following reflection. The second and third points indicate that the beams spread very quickly in velocity space. This spread in velocities could be due either to interactions between the beam and incoming solar wind ions or to some initially small velocity spread in the beam

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

    International Nuclear Information System (INIS)

    Kis, Arpad; Lemperger, Istvan; Wesztergom, Viktor; Agapitov, Oleksiy; Krasnoselskikh, Vladimir; Khotyaintsev, Yuri V.; Dandouras, Iannis

    2013-01-01

    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.

  7. 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.

  8. Surface faults in the gulf coastal plain between Victoria and Beaumont, Texas

    Science.gov (United States)

    Verbeek, Earl R.

    1979-01-01

    Displacement of the land surface by faulting is widespread in the Houston-Galveston region, an area which has undergone moderate to severe land subsidence associated with fluid withdrawal (principally water, and to a lesser extent, oil and gas). A causative link between subsidence and fluid extraction has been convincingly reported in the published literature. However, the degree to which fluid withdrawal affects fault movement in the Texas Gulf Coast, and the mechanism(s) by which this occurs are as yet unclear. Faults that offset the ground surface are not confined to the large (>6000-km2) subsidence “bowl” centered on Houston, but rather are common and characteristic features of Gulf Coast geology. Current observations and conclusions concerning surface faults mapped in a 35,000-km2 area between Victoria and Beaumont, Texas (which area includes the Houston subsidence bowl) may be summarized as follows: (1) Hundreds of faults cutting the Pleistocene and Holocene sediments exposed in the coastal plain have been mapped. Many faults lie well outside the Houston-Galveston region; of these, more than 10% are active, as shown by such features as displaced, fractured, and patched road surfaces, structural failure of buildings astride faults, and deformed railroad tracks. (2) Complex patterns of surface faults are common above salt domes. Both radial patterns (for example, in High Island, Blue Ridge, Clam Lake, and Clinton domes) and crestal grabens (for example, in the South Houston and Friendswood-Webster domes) have been recognized. Elongate grabens connecting several known and suspected salt domes, such as the fault zone connecting Mykawa, Friendswood-Webster, and Clear Lake domes, suggest fault development above rising salt ridges. (3) Surface faults associated with salt domes tend to be short (10 km), occur singly or in simple grabens, have gently sinuous traces, and tend to lie roughly parallel to the ENE-NE “coastwise” trend common to regional growth

  9. 3-D Hybrid Simulation of Quasi-Parallel Bow Shock and Its Effects on the Magnetosphere

    International Nuclear Information System (INIS)

    Lin, Y.; Wang, X.Y.

    2005-01-01

    A three-dimensional (3-D) global-scale hybrid simulation is carried out for the structure of the quasi-parallel bow shock, in particular the foreshock waves and pressure pulses. The wave evolution and interaction with the dayside magnetosphere are discussed. It is shown that diamagnetic cavities are generated in the turbulent foreshock due to the ion beam plasma interaction, and these compressional pulses lead to strong surface perturbations at the magnetopause and Alfven waves/field line resonance in the magnetosphere

  10. 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

  11. Critical experiment tests of bowing and expansion reactivity calculations for LMRS

    International Nuclear Information System (INIS)

    Schaefer, R.W.

    1988-01-01

    Experiments done in several LMR-type critical assemblies simulated core axial expansion, core radial expansion and bowing, coolant expansion, and control driveline expansion. For the most part new experimental techniques were developed to do these experiments. Calculations of the experiments basically used design-level methods, except when it was necessary to investigate complexities peculiar to the experiments. It was found that these feedback reactivities generally are overpredicted, but the predictions are within 30% of the experimental values. 14 refs., 2 figs., 4 tabs

  12. 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

    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 in terms of different antenna parameters. In addition, an investigation on the distance between...

  13. Estimation of violin bowing features from Audio recordings with Convolutional Networks

    DEFF Research Database (Denmark)

    Perez-Carillo, Alfonso; Purwins, Hendrik

    The acquisition of musical gestures and particularly of instrument controls from a musical performance is a field of increasing interest with applications in many research areas. In the last years, the development of novel sensing technologies has allowed the fine measurement of such controls...... and low-cost of the acquisition and its nonintrusive nature. The main challenge is designing robust detection algorithms to be as accurate as the direct approaches. In this paper, we present an indirect acquisition method to estimate violin bowing controls from audio signal analysis based on training...

  14. Do we really observe a bow shock in N157B...?

    OpenAIRE

    van der Swaluw, Eric

    2003-01-01

    I present a model of a pulsar wind interacting with its associated supernova remnant. I will use the model to argue that one can explain the morphology of the pulsar wind nebula inside N157B, a supernova remnant in the Large Magellanic Cloud, without the need for a bow shock interpretation. The model uses a hydrodynamics code which simulates the evolution of a pulsar wind nebula, when the pulsar is moving at a high velocity (1000 km/sec) through the expanding supernova remnant. The simulation...

  15. Discovery of an optical bow-shock around pulsar B0740-28

    OpenAIRE

    Jones, D.H.; Stappers, B.W.; Gaensler, B.M.

    2002-01-01

    We report the discovery of a faint H-alpha pulsar wind nebula (PWN) powered by the radio pulsar B0740-28. The characteristic bow-shock morphology of the PWN implies a direction of motion consistent with the previously measured velocity vector for the pulsar. The PWN has a flux density more than an order of magnitude lower than for the PWNe seen around other pulsars, but, for a distance 2 kpc, it is consistent with propagation through a medium of atomic density n_H ~ 0.25 cm^{-3}, and neutral ...

  16. 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.

  17. Faults in Linux

    DEFF Research Database (Denmark)

    Palix, Nicolas Jean-Michel; Thomas, Gaël; Saha, Suman

    2011-01-01

    In 2001, Chou et al. published a study of faults found by applying a static analyzer to Linux versions 1.0 through 2.4.1. A major result of their work was that the drivers directory contained up to 7 times more of certain kinds of faults than other directories. This result inspired a number...... of development and research efforts on improving the reliability of driver code. Today Linux is used in a much wider range of environments, provides a much wider range of services, and has adopted a new development and release model. What has been the impact of these changes on code quality? Are drivers still...... a major problem? To answer these questions, we have transported the experiments of Chou et al. to Linux versions 2.6.0 to 2.6.33, released between late 2003 and early 2010. We find that Linux has more than doubled in size during this period, but that the number of faults per line of code has been...

  18. The Sorong Fault Zone, Indonesia: Mapping a Fault Zone Offshore

    Science.gov (United States)

    Melia, S.; Hall, R.

    2017-12-01

    The Sorong Fault Zone is a left-lateral strike-slip fault zone in eastern Indonesia, extending westwards from the Bird's Head peninsula of West Papua towards Sulawesi. It is the result of interactions between the Pacific, Caroline, Philippine Sea, and Australian Plates and much of it is offshore. Previous research on the fault zone has been limited by the low resolution of available data offshore, leading to debates over the extent, location, and timing of movements, and the tectonic evolution of eastern Indonesia. Different studies have shown it north of the Sula Islands, truncated south of Halmahera, continuing to Sulawesi, or splaying into a horsetail fan of smaller faults. Recently acquired high resolution multibeam bathymetry of the seafloor (with a resolution of 15-25 meters), and 2D seismic lines, provide the opportunity to trace the fault offshore. The position of different strands can be identified. On land, SRTM topography shows that in the northern Bird's Head the fault zone is characterised by closely spaced E-W trending faults. NW of the Bird's Head offshore there is a fold and thrust belt which terminates some strands. To the west of the Bird's Head offshore the fault zone diverges into multiple strands trending ENE-WSW. Regions of Riedel shearing are evident west of the Bird's Head, indicating sinistral strike-slip motion. Further west, the ENE-WSW trending faults turn to an E-W trend and there are at least three fault zones situated immediately south of Halmahera, north of the Sula Islands, and between the islands of Sanana and Mangole where the fault system terminates in horsetail strands. South of the Sula islands some former normal faults at the continent-ocean boundary with the North Banda Sea are being reactivated as strike-slip faults. The fault zone does not currently reach Sulawesi. The new fault map differs from previous interpretations concerning the location, age and significance of different parts of the Sorong Fault Zone. Kinematic

  19. Rapid cooling rates at an active mid-ocean ridge from zircon thermochronology

    Science.gov (United States)

    Schmitt, Axel K.; Perfit, Michael R.; Rubin, Kenneth H.; Stockli, Daniel F.; Smith, Matthew C.; Cotsonika, Laurie A.; Zellmer, Georg F.; Ridley, W. Ian

    2011-01-01

    Oceanic spreading ridges are Earth's most productive crust generating environment, but mechanisms and rates of crustal accretion and heat loss are debated. Existing observations on cooling rates are ambiguous regarding the prevalence of conductive vs. convective cooling of lower oceanic crust. Here, we report the discovery and dating of zircon in mid-ocean ridge dacite lavas that constrain magmatic differentiation and cooling rates at an active spreading center. Dacitic lavas erupted on the southern Cleft segment of the Juan de Fuca ridge, an intermediate-rate spreading center, near the intersection with the Blanco transform fault. Their U–Th zircon crystallization ages (29.3-4.6+4.8 ka; 1δ standard error s.e.) overlap with the (U–Th)/He zircon eruption age (32.7 ± 1.6 ka) within uncertainty. Based on similar 238U-230Th disequilibria between southern Cleft dacite glass separates and young mid-ocean ridge basalt (MORB) erupted nearby, differentiation must have occurred rapidly, within ~ 10–20 ka at most. Ti-in-zircon thermometry indicates crystallization at 850–900 °C and pressures > 70–150 MPa are calculated from H2O solubility models. These time-temperature constraints translate into a magma cooling rate of ~ 2 × 10-2 °C/a. This rate is at least one order-of-magnitude faster than those calculated for zircon-bearing plutonic rocks from slow spreading ridges. Such short intervals for differentiation and cooling can only be resolved through uranium-series (238U–230Th) decay in young lavas, and are best explained by dissipating heat convectively at high crustal permeability.

  20. Corridors of crestal and radial faults linking salt diapirs in the Espírito Santo Basin, SE Brazil

    Science.gov (United States)

    Mattos, Nathalia H.; Alves, Tiago M.

    2018-03-01

    This work uses high-quality 3D seismic data to assess the geometry of fault families around salt diapirs in SE Brazil (Espírito Santo Basin). It aims at evaluating the timings of fault growth, and suggests the generation of corridors for fluid migration linking discrete salt diapirs. Three salt diapirs, one salt ridge, and five fault families were identified based on their geometry and relative locations. Displacement-length (D-x) plots, Throw-depth (T-z) data and structural maps indicate that faults consist of multiple segments that were reactivated by dip-linkage following a preferential NE-SW direction. This style of reactivation and linkage is distinct from other sectors of the Espírito Santo Basin where the preferential mode of reactivation is by upwards vertical propagation. Reactivation of faults above a Mid-Eocene unconformity is also scarce in the study area. Conversely, two halokinetic episodes dated as Cretaceous and Paleogene are interpreted below a Mid-Eocene unconformity. This work is important as it recognises the juxtaposition of permeable strata across faults as marking the generation of fault corridors linking adjacent salt structures. In such a setting, fault modelling shows that fluid will migrate towards the shallower salt structures along the fault corridors first identified in this work.

  1. Preliminary confirmation of a surface faulting based on geological and earthquake data in the Puspiptek Serpong area

    International Nuclear Information System (INIS)

    Hadi Suntoko; Supartoyo

    2016-01-01

    BAPETEN regulation No. 8/2013 present the requirement that the site of the nuclear industry should not be a fault capable in a radius of 5 km. It is known that the RDE site composed of sandstones, clay stone, conglomerates and pumice rework the age of Pliocene, there straightness river valley hypothesized as a fault. Potential faults are identified using morphological observation, remote sensing using DEM rock outcrops, and seismic interpretation results that aims to confirm capable faults in a radius of 5 km. Traces defence surface is focused on the observation of the appearance of the terrain (land form), in the form of straightness morphology or valleys, fault scarp (fault scarp), shift or offset (river or hill), depression formed along fault zones, saddle, pressure ridge, and the shape of the river as well as earthquake monitoring. The results showed that there was no fault capable also a surface faulting that prove the presence in the RDE site radius of 5 km. (author)

  2. The Guadalquivir Diapiric Ridge: Deep Tectonics and Related Gas Structures

    Science.gov (United States)

    Fernández-Puga, M. C.; Somoza, L.; Pinheiro, L. M.; Magalhães, V.; Vázquez, J. T.; Díaz-del-Río, V.; Ivanov, M.

    Cooperation between the Spanish TASYO project during the cruises Tasyo/2000, Anastasya/99, Anastasya/00 and Anastasya/01 and the UNESCO-IOC Trainning Trough Research Programme during the TTR9, TTR10 and TTR-11 cruises have per- mitted to identify numerous structures related to hydrocarbon seepages in the Gulf of Cadiz, located between the Africa and Eurasia plate. The interpretation of multibeam bathymetry and a large database of reflection seismic profiles shows two important morphotectonics structures: the Cadiz Diapiric Ridge (CDR) and the Guadalquivir Di- apiric Ridge (GDR). The CDR is a diapiric elongate structure located between 400 and 700m water depth, with a N-S direction. The GDR is an elongated ridge, situated west- ward of this structure and located along the shelf and slope between 300-1100m depth. This highly deformed ridge, formed by several diapirs oriented in NE-SW direction, has been mapped using industrial multifold seismic, core logs, gravity cores, dredge samples and photographs, obtained during the ANASTASYA 01/09 cruise. This data has shown that it is composed of early-middle Miocene blue marls (Maldonado et al, 1999), mud breccias and calcarenites. In fact, this diapiric structure is associated with a complex tectono-sedimentary history related to along slope gravity gliding and tec- tonic compression westward the fronts of the deformed wedges of the SOlistostromic & cedil;allochtonous unitsT (Somoza et al., 1999). According to the observed and sampled structures along the GDR, this ridge can be divided in three areas: (a) The NE area is characterized by the existence of a series of wide single sub-circular mud volcanoes (Anastasya, Tarsis and Pipoca), surrounded by a ring shaped seafloor depression. Mud breccia has been collected from these mud volcanoes (ANAS00-TG5,TG6,TG7,TG8 and ANAS01-TG2); (b) a central sector with long rounded-like crater structures, of unknown origin, from which calcarenites were collected (ANAS01-DA13); and (c) a SW

  3. ESR dating of fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon

    2003-02-01

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene

  4. Large earthquakes and creeping faults

    Science.gov (United States)

    Harris, Ruth A.

    2017-01-01

    Faults are ubiquitous throughout the Earth's crust. The majority are silent for decades to centuries, until they suddenly rupture and produce earthquakes. With a focus on shallow continental active-tectonic regions, this paper reviews a subset of faults that have a different behavior. These unusual faults slowly creep for long periods of time and produce many small earthquakes. The presence of fault creep and the related microseismicity helps illuminate faults that might not otherwise be located in fine detail, but there is also the question of how creeping faults contribute to seismic hazard. It appears that well-recorded creeping fault earthquakes of up to magnitude 6.6 that have occurred in shallow continental regions produce similar fault-surface rupture areas and similar peak ground shaking as their locked fault counterparts of the same earthquake magnitude. The behavior of much larger earthquakes on shallow creeping continental faults is less well known, because there is a dearth of comprehensive observations. Computational simulations provide an opportunity to fill the gaps in our understanding, particularly of the dynamic processes that occur during large earthquake rupture and arrest.

  5. ESR dating of fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2003-02-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene.

  6. Comparison of theory with atomic oxygen 130.4 nm radiation data from the Bow Shock ultraviolet 2 rocket flight

    Science.gov (United States)

    Levin, Deborah A.; Candler, Graham V.; Collins, Robert J.; Howlett, Carl L.; Espy, Patrick; Whiting, Ellis; Park, Chul

    1993-01-01

    Comparison is made between the results obtained from a state-of-the-art flow and radiative model and bow shock vacuum ultraviolet (VUV) data obtained the recent Bow Shock 2 Flight Experiment. An extensive data set was obtained from onboard rocket measurements at a reentry speed of 5 km/sec between the altitudes of approximately 65-85 km. A description of the NO photoionization cell used, the data, and the interpretation of the data will be presented. The primary purpose of the analyses is to assess the utility of the data and to propose a radiation model appropriate to the flight conditions of Bow Shock 2. Theoretical predictions based on flow modeling discussed in earlier work and a new radiation model are compared with data.

  7. Terahertz-wave near-field imaging with subwavelength resolution using surface-wave-assisted bow-tie aperture

    Science.gov (United States)

    Ishihara, Kunihiko; Ohashi, Keishi; Ikari, Tomofumi; Minamide, Hiroaki; Yokoyama, Hiroyuki; Shikata, Jun-ichi; Ito, Hiromasa

    2006-11-01

    We demonstrate the terahertz-wave near-field imaging with subwavelength resolution using a bow-tie shaped aperture surrounded by concentric periodic structures in a metal film. A subwavelength aperture with concentric periodic grooves, which are known as a bull's eye structure, shows extremely large enhanced transmission beyond the diffraction limit caused by the resonant excitation of surface waves. Additionally, a bow-tie aperture exhibits extraordinary field enhancement at the sharp tips of the metal, which enhances the transmission and the subwavelength spatial resolution. We introduced a bow-tie aperture to the bull's eye structure and achieved high spatial resolution (˜λ/17) in the near-field region. The terahertz-wave near-field image of the subwavelength metal pattern (pattern width=20μm) was obtained for the wavelength of 207μm.

  8. [Development Of 25-Year Imp 8 Bow Shock Crossing "List, Ingestion Of This List To Cdaweb, & Enhancement"

    Science.gov (United States)

    Merka, J.; Szabo, A.; Narock, T. W.; King, J. H.; Paularena, K. I.; Richardson, J. D.

    2003-01-01

    The MIT portion of this project was to use the plasma data from IMP 8 to identify bow shock crossings for construction of a bow shock data base. In collaboration with Goddard, we determined which shock parameters would be included in the catalog and developed a set of flags for characterizing the data. IMP 8 data from 1973-2001 were surveyed for bow shock crossings; the crossings apparent in the plasma data were compared to a list of crossing chosen in the magnetometer data by Goddard. Differences were reconciled to produce a single list. The data were then provided to the NSSDC for archiving. All the work ascribed to MIT in the proposal was completed.

  9. Preliminary results from the first InRidge cruise to the central Indian Ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Mukhopadhyay, R.; Murthy, K.S.R.; Iyer, S.D.; Rao, M.M.M.; Banerjee, R.; Subrahmanyam, A.S.; Shirodkar, P.V.; Ghose, I.; Ganesan, P.; Rao, A.K.; Suribabu, A.; Ganesh, C.; Naik, G.P.

    stream_size 1 stream_content_type text/plain stream_name Inter_Ridge_News_7_40.pdf.txt stream_source_info Inter_Ridge_News_7_40.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  10. An aerial radiological survey of the Oak Ridge Reservation, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Maurer, R.J.

    1993-04-01

    An aerial radiological survey of the Oak Ridge Reservation (ORR) and surrounding area in Oak Ridge, Tennessee, was conducted during the period March 30 to April 14,1992. The purpose of the survey was to measure and document the terrestrial radiological environment of the Oak Ridge Reservation for use in environmental management programs and emergency response planning. The aerial survey was flown at an altitude of 150 feet (46 meters) along a series of parallel lines 250 feet (76 meters) apart and included X-10 (Oak Ridge National Laboratory), K-25 (former Gaseous Diffusion Plant), Y-12 (Weapons Production Plant), the Freels Bend Area and Oak Ridge Institute for Science and Education, the East Fork Poplar Creek (100-year floodplain extending from K-25 to Y-12), Elza Gate (former uranium ore storage site located in the city of Oak Ridge), Parcel A, the Clinch River (river banks extending from Melton Hill Dam to the city of Kingston), and the CSX Railroad Tracks (extending from Y-12 to the city of Oak Ridge). The survey encompassed approximately 55 square miles (1 41 square kilometers) of the Oak Ridge Reservation and surrounding area

  11. Real-time fault diagnosis and fault-tolerant control

    OpenAIRE

    Gao, Zhiwei; Ding, Steven X.; Cecati, Carlo

    2015-01-01

    This "Special Section on Real-Time Fault Diagnosis and Fault-Tolerant Control" of the IEEE Transactions on Industrial Electronics is motivated to provide a forum for academic and industrial communities to report recent theoretic/application results in real-time monitoring, diagnosis, and fault-tolerant design, and exchange the ideas about the emerging research direction in this field. Twenty-three papers were eventually selected through a strict peer-reviewed procedure, which represent the mo...

  12. Gravimetric structure for the abyssal mantle massif of Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean, and its relation to active uplift

    Directory of Open Access Journals (Sweden)

    KENJI F. MOTOKI

    2014-06-01

    Full Text Available This paper presents gravimetric and morphologic analyses based on the satellite-derived data set of EGM2008 and TOPEX for the area of the oceanic mantle massif of the Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean. The free-air anomaly indicates that the present plate boundary is not situated along the longitudinal graben which cuts peridotite ridge, but about 20 km to the north of it. The high Bouguer anomaly of the peridotite ridge suggests that it is constituted mainly by unserpentinised ultramafic rocks. The absence of isostatic compensation and low-degree serpentinisation of the ultramafic rocks indicate that the peridotite ridge is sustained mainly by active tectonic uplift. The unparallel relation between the transform fault and the relative plate motion generates near north-south compression and the consequent tectonic uplift. In this sense, the peridotite massif is a pressure ridge due to the strike-slip displacement of the Saint Paul Transform Fault.

  13. Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

    KAUST Repository

    Metwally, Ahmed Mohsen Hassan

    2017-05-31

    We propose a novel method for imaging shallow faults by migration of transmitted refraction arrivals. The assumption is that there is a significant velocity contrast across the fault boundary that is underlain by a refracting interface. This procedure, denoted as refraction migration with fault flooding, largely overcomes the difficulty in imaging shallow faults with seismic surveys. Numerical results successfully validate this method on three synthetic examples and two field-data sets. The first field-data set is next to the Gulf of Aqaba and the second example is from a seismic profile recorded in Arizona. The faults detected by refraction migration in the Gulf of Aqaba data were in agreement with those indicated in a P-velocity tomogram. However, a new fault is detected at the end of the migration image that is not clearly seen in the traveltime tomogram. This result is similar to that for the Arizona data where the refraction image showed faults consistent with those seen in the P-velocity tomogram, except it also detected an antithetic fault at the end of the line. This fault cannot be clearly seen in the traveltime tomogram due to the limited ray coverage.

  14. Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

    KAUST Repository

    Metwally, Ahmed Mohsen Hassan; Hanafy, Sherif; Guo, Bowen; Kosmicki, Maximillian Sunflower

    2017-01-01

    We propose a novel method for imaging shallow faults by migration of transmitted refraction arrivals. The assumption is that there is a significant velocity contrast across the fault boundary that is underlain by a refracting interface. This procedure, denoted as refraction migration with fault flooding, largely overcomes the difficulty in imaging shallow faults with seismic surveys. Numerical results successfully validate this method on three synthetic examples and two field-data sets. The first field-data set is next to the Gulf of Aqaba and the second example is from a seismic profile recorded in Arizona. The faults detected by refraction migration in the Gulf of Aqaba data were in agreement with those indicated in a P-velocity tomogram. However, a new fault is detected at the end of the migration image that is not clearly seen in the traveltime tomogram. This result is similar to that for the Arizona data where the refraction image showed faults consistent with those seen in the P-velocity tomogram, except it also detected an antithetic fault at the end of the line. This fault cannot be clearly seen in the traveltime tomogram due to the limited ray coverage.

  15. Multicentre randomised double bind crossover trial on contamination of conventional ties and bow ties in routine obstetric and gynaecological practice.

    Science.gov (United States)

    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 saline was taken from specific area on ties at end of first and third working days and sent in transport medium for culture on chocolatised blood and MacConkey agar for 48 hours. MAIN OUTCOME MEASURES--Level of bacteriological growth assessed semiquantitatively (0 for no contamination; for heavy contamination) after swabs had been cultured. At end of study the participants completed a questionnaire to assess their attitude toward wearing different types of necktie. RESULTS--12 doctors (80%) completed the study. Although bow ties were significantly less contaminated at end of first working day (z = -2.354, p = 0.019), this difference was not maintained; there was no difference in level of contamination on third day. Level of contamination did not increase between first and third day of wearing the same garment. One of the 10 doctors who returned the questionnaire found the bow tie very uncomfortable. All participants would consider wearing a bow tie if it proved to be less contaminated than a conventional tie. CONCLUSIONS--Although a significant difference in contamination was established between conventional and bow ties on first day of study, this difference was not confirmed on third day and there is unlikely to be any real association between tie type and bacterial contamination. Because of its negative image and difficulty to tie, the bow tie will probably remain a minority fashion. Images p1583-a PMID:8292945

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

    Science.gov (United States)

    Li, Xinhua; Shi, Jim Q.; Zhang, Da; Singh, Sarabjeet; Padole, Atul; Otrakji, Alexi; Kalra, Mannudeep K.; Xu, X. George; Liu, Bob

    2015-01-01

    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. PMID:26520720

  17. Uranium-lead isotopic ages of the Samail ophiolite, Oman, with applicatons to Tethyan ocean ridge tectonics

    International Nuclear Information System (INIS)

    Tilton, G.R.; Hopson, C.A.; Wright, J.E.

    1981-01-01

    Plagiogranites are a minor but widespread component of the Samail ophiolite plutonic member. They crystallized from the most fractionated melts generated by magmatic crystallization and differentiation of a steady state magma chamber beneath the Tethyan spreading ocean ridge, and their ages are thought to mark the time of ocean crust formation. Isotopic U--Pb ages of zircons from 13 plagiogranites collected along a 270-km segment of the Samail ophiolite subparallel to the regional trend of the sheeted dike complex (the former spreading ridge axis direction) define a narrow time interval of 93.5--97.9 m.y., with a pronounced clustering about 95 m.y. The zircon ages of the plagiogranites agree remarkably well with the early Cenomanian to early Turonian biostratigraphic ages of sediments that are intercalated within the ophiolite pillow lavas and that lie just above them (Tippit et al., 1981). The agreement of radiometric and biostratigraphic ages provides strong support for the conclusion that the plagiogranite U--Pb ages closely date the time span of ocean crust formation. No step changes in age patterns are observed along the ridge axis (sheeted dike) direction, suggesting that there are no major internal offsets of the ophiolite by transform or other faults along most of the traverse. One possible exception occurs at the southeastern end of the sampled interval (Ibra area), where a 3 m.y. discontinuity might be caused by an unmapped fault. Assuming that the regional trend of the sheeted dikes (N10 0 --25 0 W) marks the direction of the former spreading ridge axis, the present array of sample localities spans a distance of 130 to 195 km normal to that axis (i.e., in the spreading direction). The data as a whole do not define a clear-cut age trend normal to the spreading axis, but by eliminating samples that may be aberrant due to faulting, the data array suggests a pattern of increasing ages from east to west

  18. Gas Migration Processes through the Gas Hydrate Stability Zone at Four-Way Closure Ridge Offshore SW Taiwan

    Science.gov (United States)

    Kunath, P.; Chi, W. C.; Berndt, C.; Liu, C. S.

    2016-12-01

    We have used 3D P-Cable seismic data from Four-Way-Closure Ridge, a NW-SE trending anticlinal ridge within the lower slope domain of accretionary wedge, to investigate the geological constraints influencing the fluid migration pattern in the shallow marine sediments. In the seismic data, fluid migration feature manifests itself as high reflection layers of dipping strata, which originate underneath a bottom simulating reflector (BSR) and extend towards the seafloor. Shoaling of the BSR near fluid migration pathways indicates a focused fluid flux, perturbing the temperature field. Furthermore, seafloor video footage confirmed the presence of recent methane seepage above seismically imaged fluid migration pathways. We plan to test two hypotheses for the occurrence of these fluid migration pathways: 1) the extensional regime under the anticlinal ridge crest caused the initiation of localized fault zones, acting as fluid conduits in the gas hydrate stability zone (GHSZ). 2) sediment deformation induced by focused fluid flow and massive growth and dissolution of gas hydrate, similar to processes controlling the evolution of pockmarks on the Nigerian continental margin. We suggest that these processes may be responsible for the formation of a massive hydrate core in the crest of the anticline, as inferred from other geophysical datasets. Triggering process for fluid migration cannot be clearly defined. However, the existence of blind thrust faults may help to advect deep-seated fluids. This may be augmented by biogenic production of shallow gas underneath the ridge, where the excess of gas enables the coexistence of gas, water, and gas hydrate within the GHSZ. Fluid migration structures may exists because of the buoyancy of gas-bearing fluids. This study shows a potential model on how gas-bearing fluids migrate upward towards structural highs, which might occur in other anticlinal structures around the world. Keywords: P-Cable, gas-hydrate, fluid flow, fault-related fold

  19. BOW. A computer code to predict lateral deflections of composite beams. A computer code to predict lateral deflections of composite beams

    Energy Technology Data Exchange (ETDEWEB)

    Tayal, M.

    1987-08-15

    Arrays of tubes are used in many engineered structures, such as in nuclear fuel bundles and in steam generators. The tubes can 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 endcap 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.

  20. Remedial Investigation Work Plan for Chestnut Ridge Operable Unit 1 (Chestnut Ridge Security Pits) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1994-03-01

    This document outlines the activities necessary to conduct a Remedial Investigation (RI) of the Chestnut Ridge Security Pits (CRSP) at the Oak Ridge Y-12 Plant. The CRSP, also designated Chestnut Ridge Operable Unit (OU) 1, is one of four OUs along Chestnut Ridge on the Oak Ridge Reservation (ORR). The purpose of the RI is to collect data to (1) evaluate the nature and extent of known and suspected contaminants, (2) support an Ecological Risk Assessment (ERA) and a Human Health Risk Assessment (HHRA), (3) support the feasibility study in the development and analysis of remedial alternatives, and (4) ultimately, develop a Record of Decision (ROD) for the site. This chapter summarizes the regulatory background of environmental investigation on the ORR and the approach currently being followed and provides an overview of the RI to be conducted at the CRSP. Subsequent chapters provide details on site history, sampling activities, procedures and methods, quality assurance (QA), health and safety, and waste management related to the RI

  1. Remedial Investigation Work Plan for Chestnut Ridge Operable Unit 1 (Chestnut Ridge Security Pits) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1994-03-01

    This document outlines the activities necessary to conduct a Remedial Investigation (RI) of the Chestnut Ridge Security Pits (CRSP) at the Oak Ridge Y-12 Plant. The CRSP, also designated Chestnut Ridge Operable Unit (OU) 1, is one of four OUs along Chestnut Ridge on the Oak Ridge Reservation (ORR). The purpose of the RI is to collect data to (1) evaluate the nature and extent of known and suspected contaminants, (2) support an Ecological Risk Assessment (ERA) and a Human Health Risk Assessment (HHRA), (3) support the feasibility study in the development and analysis of remedial alternatives, and (4) ultimately, develop a Record of Decision (ROD) for the site. This chapter summarizes the regulatory background of environmental investigation on the ORR and the approach currently being followed and provides an overview of the RI to be conducted at the CRSP. Subsequent chapters provide details on site history, sampling activities, procedures and methods, quality assurance (QA), health and safety, and waste management related to the RI.

  2. TH-CD-207B-05: Measurement of CT Bow-Tie Profiles Using a Linear Array Detector

    Energy Technology Data Exchange (ETDEWEB)

    Yang, K; Li, X; Liu, B [Massachusetts General Hospital, Boston, MA (United States)

    2016-06-15

    Purpose: To accurately measure CT bow-tie profiles from various manufacturers and to provide non-proprietary information for CT system modeling. Methods: A GOS-based linear detector (0.8 mm per pixel and 51.2 cm in length) with a fast data sampling speed (0.24 ms/sample) was used to measure the relative profiles of bow-tie filters from a collection of eight CT scanners by three different vendors, GE (LS Xtra, LS VCT, Discovery HD750), Siemens (Sensation 64, Edge, Flash, Force), and Philips (iBrilliance 256). The linear detector was first calibrated for its energy response within typical CT beam quality ranges and compared with an ion chamber and analytical modeling (SPECTRA and TASMIP). A geometrical calibration process was developed to determine key parameters including the distance from the focal spot to the linear detector, the angular increment of the gantry at each data sampling, the location of the central x-ray on the linear detector, and the angular response of the detector pixel. Measurements were performed under axial-scan modes for most representative bow-tie filters and kV selections from each scanner. Bow-tie profiles were determined by re-binning the measured rotational data with an angular accuracy of 0.1 degree using the calibrated geometrical parameters. Results: The linear detector demonstrated an energy response as a solid state detector, which is close to the CT imaging detector. The geometrical calibration was proven to be sufficiently accurate (< 1mm in error for distances >550 mm) and the bow-tie profiles measured from rotational mode matched closely to those from the gantry-stationary mode. Accurate profiles were determined for a total of 21 bow-tie filters and 83 filter/kV combinations from the abovementioned scanner models. Conclusion: A new improved approach of CT bow-tie measurement was proposed and accurate bow-tie profiles were provided for a broad list of CT scanner models.

  3. Wilshire fault: Earthquakes in Hollywood?

    Science.gov (United States)

    Hummon, Cheryl; Schneider, Craig L.; Yeats, Robert S.; Dolan, James F.; Sieh, Kerry E.; Huftile, Gary J.

    1994-04-01

    The Wilshire fault is a potentially seismogenic, blind thrust fault inferred to underlie and cause the Wilshire arch, a Quaternary fold in the Hollywood area, just west of downtown Los Angeles, California. Two inverse models, based on the Wilshire arch, allow us to estimate the location and slip rate of the Wilshire fault, which may be illuminated by a zone of microearthquakes. A fault-bend fold model indicates a reverse-slip rate of 1.5-1.9 mm/yr, whereas a three-dimensional elastic-dislocation model indicates a right-reverse slip rate of 2.6-3.2 mm/yr. The Wilshire fault is a previously unrecognized seismic hazard directly beneath Hollywood and Beverly Hills, distinct from the faults under the nearby Santa Monica Mountains.

  4. What is Fault Tolerant Control

    DEFF Research Database (Denmark)

    Blanke, Mogens; Frei, C. W.; Kraus, K.

    2000-01-01

    Faults in automated processes will often cause undesired reactions and shut-down of a controlled plant, and the consequences could be damage to the plant, to personnel or the environment. Fault-tolerant control is the synonym for a set of recent techniques that were developed to increase plant...... availability and reduce the risk of safety hazards. Its aim is to prevent that simple faults develop into serious failure. Fault-tolerant control merges several disciplines to achieve this goal, including on-line fault diagnosis, automatic condition assessment and calculation of remedial actions when a fault...... is detected. The envelope of the possible remedial actions is wide. This paper introduces tools to analyze and explore structure and other fundamental properties of an automated system such that any redundancy in the process can be fully utilized to enhance safety and a availability....

  5. Detailed study of electron plasma waves upstream of the earth's bow shock

    International Nuclear Information System (INIS)

    Etcheto, J.; Faucheux, M.

    1984-01-01

    A detailed study of electron plasma waves observed upstream of the earth's bow shock and of their relationships to the position of the satellite in the foreshock and to the electron measurements has been carried out. The wave characteristics depend on the position in the electron foreshock: a narrow-bnd (a few percent) and intense (a few millivolts per meter) noise is observed at the plasma frequency at the edge of the foreshock while the spectrum widens (Δf/fapprox. =0.3) at the same time as the power decreases (hundreds of microvolts per meter) deeper (a few earth radii) inside the foreshock. Signals below the plasma frequency are also observed. These waves are polarized along the magnetic field, with long wavelengths below and at the plasma frequency and short wavelengths above it. They appear as short bursts, the duration of which depends on the frequency: longer close to the plasma frequency (50 ms), they shorten with increasing separation from the plasma frequency, the usual duration being 15 ms. While the correlation of the wave characteristics with the reflected electrons is good as the satellite moves inside the foreshock, no evolution is found with the distance to the bow shock, neither for the noise nor for the particles. These results are discussed in the frame of various mechanisms which have been proposed to explain these upstream waves but no satisfactory agreement is found with any of them

  6. Structure of oblique subcritical bow shocks: ISEE 1 and 2 observations

    International Nuclear Information System (INIS)

    Mellott, M.M.; Greenstadt, E.W.

    1984-01-01

    We have studied the structural elements, including shock ramps and precursor wave trains, of a series of oblique low-Mach number terrestrial bow shocks. We used magnetic field data from the dual ISEE 1 and 2 spacecraft to determine the scale lengths of various elements of shock structure as well as wavelengths and wave polarizations. Bow shocks structure under these conditions is esstentially that of a large-amplitude damped whistler mode wave which extends upstream in the form of a precursor wave train. Shock thicknesses, which are determined by the dispersive properties of the ambient plasma, are too broad to support current-driven electrostatic waves, ruling out such turbulence as the source of dissipation in these shocks. Dissipative processes are reflected in the damping of the precursors, and dissipative scale lengths are approx.200--800 km (several times greater than shock thicknesses). Precursor damping is not related to shock normal angle or Mach number, but is correlated with T/sub e//T/sub t/. The source of the dissipation in the shocks does not appear to be wave-wave decay of the whistlers, for which no evidence is found. We cannot rule out the possibility of contribution to the dissipation from ion acoustic and, or lower hybrid mode turbulence, but interaction of the whistler itself with upstream electrons offers a simpler and more self-consistent explanation for the observed wave train damping

  7. COMPUTING THE DUST DISTRIBUTION IN THE BOW SHOCK OF A FAST-MOVING, EVOLVED STAR

    International Nuclear Information System (INIS)

    Van Marle, A. J.; Meliani, Z.; Keppens, R.; Decin, L.

    2011-01-01

    We study the hydrodynamical behavior occurring in the turbulent interaction zone of a fast-moving red supergiant star, where the circumstellar and interstellar material collide. In this wind-interstellar-medium collision, the familiar bow shock, contact discontinuity, and wind termination shock morphology form, with localized instability development. Our model includes a detailed treatment of dust grains in the stellar wind and takes into account the drag forces between dust and gas. The dust is treated as pressureless gas components binned per grain size, for which we use 10 representative grain size bins. Our simulations allow us to deduce how dust grains of varying sizes become distributed throughout the circumstellar medium. We show that smaller dust grains (radius <0.045 μm) tend to be strongly bound to the gas and therefore follow the gas density distribution closely, with intricate fine structure due to essentially hydrodynamical instabilities at the wind-related contact discontinuity. Larger grains which are more resistant to drag forces are shown to have their own unique dust distribution, with progressive deviations from the gas morphology. Specifically, small dust grains stay entirely within the zone bound by shocked wind material. The large grains are capable of leaving the shocked wind layer and can penetrate into the shocked or even unshocked interstellar medium. Depending on how the number of dust grains varies with grain size, this should leave a clear imprint in infrared observations of bow shocks of red supergiants and other evolved stars.

  8. The upstream escape of energized solar wind protons from the bow shock

    International Nuclear Information System (INIS)

    Greenstadt, E.W.

    1975-01-01

    Recently, there have been some systematic observations of backstreaming protons at the Earth's bow shock with parallel velocity components and total energies much too high to be associated with the usual long-period upstream waves or to be produced by Sonnerup's simple reflection process (Lin et al., 1974), and these protons (30-100keV) were attributed to some unknown acceleration mechanism in the upstream region. The observations of Lof et al. involved protons in high pitch angle, and, although their reasons for favoring an upstream acceleration were quite different, it may seem intuitive that high pitch angle particles would have difficulty escaping the shock, especially at large field-normal angles. Such an inference would superficially support the notion of energization outside the bow shock. It seems worthwhile therefore to examine the extent to which the geometry of individual particle motion alone might select among reflected particles those that can escape upstream and those that cannot. In this paper the geometry of escape is described and some simple numerical examples are worked out for a few special cases. It is found that protons with rather high energies and pitch angles can escape the shock at only marginally quasi-parallel field orientations (i.e., thetasub(nB) approximately 50 0 ), even if they have quite moderate speeds parallel to B. (Auth.)

  9. Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse

    Science.gov (United States)

    Zhang, Shun-Rong; Erickson, Philip J.; Goncharenko, Larisa P.; Coster, Anthea J.; Rideout, William; Vierinen, Juha

    2017-12-01

    During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including not only the stratosphere but also the thermosphere and ionosphere. The eclipse shadow has a supersonic motion which is theoretically expected to generate atmospheric bow waves, similar to a fast-moving river boat, with waves starting in the lower atmosphere and propagating into the ionosphere. However, previous geographically limited observations have had difficulty detecting these weak waves within the natural background atmospheric variability, and the existence of eclipse-induced ionospheric waves and their evolution in a complex coupling system remain controversial. During the 21 August 2017 eclipse, high fidelity and wide coverage ionospheric observations provided for the first time an oversampled set of eclipse data, using a dense network of Global Navigation Satellite System receivers at ˜2,000 sites in North America. We show the first unambiguous evidence of ionospheric bow waves as electron content disturbances over central/eastern United States, with ˜1 h duration, 300-400 km wavelength and 280 m/s phase speed emanating from and tailing the totality region. We also identify large ionospheric perturbations moving at the supersonic speed of the maximum solar obscuration which are too fast to be associated with known gravity wave or large-scale traveling ionospheric disturbance processes. This study reveals complex interconnections between the Sun, Moon, and Earth's neutral atmosphere and ionosphere and demonstrates persistent coupling processes between different components of the Earth's atmosphere, a topic of significant community interest.

  10. High-order harmonics from bow wave caustics driven by a high-intensity laser

    International Nuclear Information System (INIS)

    Pirozhkov, A.S.; Kando, M.; Esirkepov, T.Zh.

    2012-01-01

    We propose a new mechanism of high-order harmonic generation during an interaction of a high-intensity laser pulse with underdense plasma. A tightly focused laser pulse creates a cavity in plasma pushing electrons aside and exciting the wake wave and the bow wave. At the joint of the cavity wall and the bow wave boundary, an annular spike of electron density is formed. This spike surrounds the cavity and moves together with the laser pulse. Collective motion of electrons in the spike driven by the laser field generates high-order harmonics. A strong localization of the electron spike, its robustness to oscillations imposed by the laser field and, consequently, its ability to produce high-order harmonics is explained by catastrophe theory. The proposed mechanism explains the experimental observations of high-order harmonics with the 9 TW J-KAREN laser (JAEA, Japan) and the 120 TW Astra Gemini laser (CLF RAL, UK) [A. S. Pirozhkov, et al., arXiv:1004.4514 (2010); A. S. Pirozhkov et al, AIP Proceedings, this volume]. The theory is corroborated by high-resolution two-and three-dimensional particle-in-cell simulations.

  11. Bow Shock Generator Current Systems: MMS Observations of Possible Current Closure

    Science.gov (United States)

    Hamrin, M.; Gunell, H.; Lindkvist, J.; Lindqvist, P.-A.; Ergun, R. E.; Giles, B. L.

    2018-01-01

    We use data from the first two dayside seasons of the Magnetospheric Multiscale (MMS) mission to study current systems associated with quasi-perpendicular bow shocks of generator type. We have analyzed 154 MMS bow shock crossings near the equatorial plane. We compute the current density during the crossings and conclude that the component perpendicular to the shock normal (J⊥) is consistent with a pileup of the interplanetary magnetic field (IMF) inside the magnetosheath. For predominantly southward IMF, we observe a component Jn parallel (antiparallel) to the normal for GSM Y > 0 (MMS probing region. For IMF clock angles near 90∘, we find indications of the current system being tilted toward the north-south direction, obtaining a significant Jz component, and we suggest that the current closes off the equatorial plane at higher latitudes where the spacecraft are not probing. The observations are complicated for several reasons. For example, variations in the solar wind and the magnetospheric currents and loads affect the closure, and Jn is distributed over large regions, making it difficult to resolve inside the magnetosheath proper.

  12. The cometary H II regions of DR 21: Bow shocks or champagne flows or both?

    Science.gov (United States)

    Immer, K.; Cyganowski, C.; Reid, M. J.; Menten, K. M.

    2014-03-01

    We present deep Very Large Array H66α radio recombination line (RRL) observations of the two cometary H II regions in DR 21. With these sensitive data, we test the "hybrid" bow shock/champagne flow model previously proposed for the DR 21 H II regions. The ionized gas down the tail of the southern H II region is redshifted by up to ~30 km s-1 with respect to the ambient molecular gas, as expected in the hybrid scenario. The RRL velocity structure, however, reveals the presence of two velocity components in both the northern and southern H II regions. This suggests that the ionized gas is flowing along cone-like shells, swept-up by stellar winds. The observed velocity structure of the well-resolved southern H II region is most consistent with a picture that combines a stellar wind with stellar motion (as in bow shock models) along a density gradient (as in champagne flow models). The direction of the implied density gradient is consistent with that suggested by maps of dust continuum and molecular line emission in the DR 21 region. The image cubes are only available as a FITS file at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A39Table 2, Fig. 4, and Appendices A and B are available in electronic form at http://www.aanda.org

  13. Cooling rates and the depth of detachment faulting at oceanic core complexes: Evidence from zircon Pb/U and (U-Th)/He ages

    Science.gov (United States)

    Grimes, Craig B.; Cheadle, Michael J.; John, Barbara E.; Reiners, P.W.; Wooden, J.L.

    2011-01-01

    Oceanic detachment faulting represents a distinct mode of seafloor spreading at slow spreading mid-ocean ridges, but many questions persist about the thermal evolution and depth of faulting. We present new Pb/U and (U-Th)/He zircon ages and combine them with magnetic anomaly ages to define the cooling histories of gabbroic crust exposed by oceanic detachment faults at three sites along the Mid-Atlantic Ridge (Ocean Drilling Program (ODP) holes 1270D and 1275D near the 15??20???N Transform, and Atlantis Massif at 30??N). Closure temperatures for the Pb/U (???800??C-850??C) and (U-Th)/He (???210??C) isotopic systems in zircon bracket acquisition of magnetic remanence, collectively providing a temperature-time history during faulting. Results indicate cooling to ???200??C in 0.3-0.5 Myr after zircon crystallization, recording time-averaged cooling rates of ???1000??C- 2000??C/Myr. Assuming the footwalls were denuded along single continuous faults, differences in Pb/U and (U-Th)/He zircon ages together with independently determined slip rates allow the distance between the ???850??C and ???200??C isotherms along the fault plane to be estimated. Calculated distances are 8.4 ?? 4.2 km and 5.0 2.1 km from holes 1275D and 1270D and 8.4 ?? 1.4 km at Atlantis Massif. Estimating an initial subsurface fault dip of 50 and a depth of 1.5 km to the 200??C isotherm leads to the prediction that the ???850??C isotherm lies ???5-7 km below seafloor at the time of faulting. These depth estimates for active fault systems are consistent with depths of microseismicity observed beneath the hypothesized detachment fault at the TAG hydrothermal field and high-temperature fault rocks recovered from many oceanic detachment faults. Copyright 2011 by the American Geophysical Union.

  14. Alpine Fault, New Zealand, SRTM Shaded Relief and Colored Height

    Science.gov (United States)

    2005-01-01

    The Alpine fault runs parallel to, and just inland of, much of the west coast of New Zealand's South Island. This view was created from the near-global digital elevation model produced by the Shuttle Radar Topography Mission (SRTM) and is almost 500 kilometers (just over 300 miles) wide. Northwest is toward the top. The fault is extremely distinct in the topographic pattern, nearly slicing this scene in half lengthwise. In a regional context, the Alpine fault is part of a system of faults that connects a west dipping subduction zone to the northeast with an east dipping subduction zone to the southwest, both of which occur along the juncture of the Indo-Australian and Pacific tectonic plates. Thus, the fault itself constitutes the major surface manifestation of the plate boundary here. Offsets of streams and ridges evident in the field, and in this view of SRTM data, indicate right-lateral fault motion. But convergence also occurs across the fault, and this causes the continued uplift of the Southern Alps, New Zealand's largest mountain range, along the southeast side of the fault. Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast (image top to bottom) direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data

  15. Hydrology of Alkali Creek and Castle Valley Ridge coal-lease tracts, central Utah, and potential effects of coal mining

    Science.gov (United States)

    Seiler, R.L.; Baskin, R.L.

    1988-01-01

    The Alkali Creek coal-lease tract includes about 2,150 acres in the Book Cliffs coal field in central Utah, and the Castle Valley Ridge coal-lease tract includes about 3,360 acres in the Wasatch Plateau coal field, also in central Utah. Both the Alkali Creek and Castle Valley Ridge coal-lease tracts are near areas where coal is currently (1987) mined by underground methods from the Cretaceous Blackhawk Formation. The Alkali Creek and Castle Valley Ridge areas have intermittent streams in which flow after snowmelt runoff is locally sustained into midsummer by springflow. The only perennial stream is South Fork Corner Canyon Creek in the Castle Valley Ridge area. Peak flow in both areas generally is from snowmelt runoff; however, peak flow from thunderstorm runoff in the Alkali Creek area can exceed that from snowmelt runoff. Estimated annual source-area sediment yield was 0.5 acre-ft/sq mi in the Alkali Creek lease tract and it was 0.3 acre-ft/sq mi in the Castle Valley Ridge lease tract. Groundwater in the Alkali Creek area occurs in perched aquifers in the Flagstaff Limestone and in other formations above the coal-bearing Blackhawk Formation. The principal source of recharge to the aquifers is snowmelt on outcrops. Faults may be major conduits and control the movement of groundwater. Groundwater discharges at formation contacts, between zones of differing permeability within a formation, near faults and into mines. Water sampled from 13 springs in the Alkali Creek area contained dissolved solids at concentrations ranging from 273 to 5,210 mg/L. Water sampled from 17 springs in the Castle Valley Ridge area contained dissolved solids at concentrations ranging from 208 to 579 mg/L. The composition of water from a recently abandoned part of an active mine the Wasatch Plateau closely resembles that of water discharging from a nearby mine that has been abandoned for more than 30 years. Mining of the Alkali Creek and Castle Valley Ridge coal-lease tracts likely will

  16. Fault Activity in the Terrebonne Trough, Southeastern Louisiana: A Continuation of Salt-Withdrawal Fault Activity from the Miocene into the late Quaternary and Implication for Subsidence Hot-Spots

    Science.gov (United States)

    Akintomide, A. O.; Dawers, N. H.

    2017-12-01

    The observed displacement along faults in southeastern Louisiana has raised questions about the kinematic history of faults during the Quaternary. The Terrebonne Trough, a Miocene salt withdrawal basin, is bounded by the Golden Meadow fault zone on its northern boundary; north dipping, so-called counter-regional faults, together with a subsurface salt ridge, define its southern boundary. To date, there are relatively few published studies on fault architecture and kinematics in the onshore area of southeastern Louisiana. The only publically accessible studies, based on 2d seismic reflection profiles, interpreted faults as mainly striking east-west. Our interpretation of a 3-D seismic reflection volume, located in the northwestern Terrebonne Trough, as well as industry well log correlations define a more complex and highly-segmented fault architecture. The northwest striking Lake Boudreaux fault bounds a marsh on the upthrown block from Lake Boudreaux on the downthrown block. To the east, east-west striking faults are located at the Montegut marsh break and north of Isle de Jean Charles. Portions of the Lake Boudreaux and Isle de Jean Charles faults serve as the northern boundary of the Madison Bay subsidence hot-spot. All three major faults extend to the top of the 3d seismic volume, which is inferred to image latest Pleistocene stratigraphy. Well log correlation using 11+ shallow markers across these faults and kinematic techniques such as stratigraphic expansion indices indicate that all three faults were active in the middle(?) and late Pleistocene. Based on expansion indices, both the Montegut and Isle de Jean Charles faults were active simultaneously at various times, but with different slip rates. There are also time intervals when the Lake Boudreaux fault was slipping at a faster rate compared to the east-west striking faults. Smaller faults near the margins of the 3d volume appear to relate to nearby salt stocks, Bully Camp and Lake Barre. Our work to date

  17. 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.

  18. Advanced cloud fault tolerance system

    Science.gov (United States)

    Sumangali, K.; Benny, Niketa

    2017-11-01

    Cloud computing has become a prevalent on-demand service on the internet to store, manage and process data. A pitfall that accompanies cloud computing is the failures that can be encountered in the cloud. To overcome these failures, we require a fault tolerance mechanism to abstract faults from users. We have proposed a fault tolerant architecture, which is a combination of proactive and reactive fault tolerance. This architecture essentially increases the reliability and the availability of the cloud. In the future, we would like to compare evaluations of our proposed architecture with existing architectures and further improve it.

  19. Final Technical Report: PV Fault Detection Tool.

    Energy Technology Data Exchange (ETDEWEB)

    King, Bruce Hardison [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

  20. Fault current limiter

    Science.gov (United States)

    Darmann, Francis Anthony

    2013-10-08

    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  1. Width of surface rupture zone for thrust earthquakes: implications for earthquake fault zoning

    Directory of Open Access Journals (Sweden)

    P. Boncio

    2018-01-01

    Full Text Available The criteria for zoning the surface fault rupture hazard (SFRH along thrust faults are defined by analysing the characteristics of the areas of coseismic surface faulting in thrust earthquakes. Normal and strike–slip faults have been deeply studied by other authors concerning the SFRH, while thrust faults have not been studied with comparable attention. Surface faulting data were compiled for 11 well-studied historic thrust earthquakes occurred globally (5.4 ≤ M ≤ 7.9. Several different types of coseismic fault scarps characterize the analysed earthquakes, depending on the topography, fault geometry and near-surface materials (simple and hanging wall collapse scarps, pressure ridges, fold scarps and thrust or pressure ridges with bending-moment or flexural-slip fault ruptures due to large-scale folding. For all the earthquakes, the distance of distributed ruptures from the principal fault rupture (r and the width of the rupture zone (WRZ were compiled directly from the literature or measured systematically in GIS-georeferenced published maps. Overall, surface ruptures can occur up to large distances from the main fault ( ∼ 2150 m on the footwall and  ∼  3100 m on the hanging wall. Most of the ruptures occur on the hanging wall, preferentially in the vicinity of the principal fault trace ( >   ∼  50 % at distances  <   ∼  250 m. The widest WRZ are recorded where sympathetic slip (Sy on distant faults occurs, and/or where bending-moment (B-M or flexural-slip (F-S fault ruptures, associated with large-scale folds (hundreds of metres to kilometres in wavelength, are present. A positive relation between the earthquake magnitude and the total WRZ is evident, while a clear correlation between the vertical displacement on the principal fault and the total WRZ is not found. The distribution of surface ruptures is fitted with probability density functions, in order to define a criterion to

  2. Alveolar Ridge Carcinoma. Two Cases Report

    International Nuclear Information System (INIS)

    Pupo Triguero, Raul J; Vivar Bauza, Miriam; Alvarez Infante, Elisa

    2008-01-01

    Two cases with alveolar ridge carcinoma due to prosthetist traumatism are discussed in this paper, after 9 and 10 years of using dental prosthesis. Both patients began with disturbance in the alveolar ridge. The clinical examination and biopsy showed a well differenced carcinoma. The treatment was radical surgery and radiotherapy in the first patient, and conservative surgery with radiotherapy in the second case .The patients had xerostomia after radiotherapy and the woman had difficulties with mastication. The advantages and disadvantages of the treatment were discussed, focused on the prevention and treatment for oral

  3. ORLANDO - Oak Ridge Large Neutrino Detector

    International Nuclear Information System (INIS)

    Bugg, W.; Cohn, H.; Efremenko, Yu.; Fazely, A.; Gabriel, T.; Kamyshkov, Yu.; Plasil, F.; Svoboda, R.

    1999-01-01

    We discuss a proposal for construction of an Oak Ridge LArge Neutrino DetectOr (ORLANDO) to search for neutrino oscillations at the Spallation Neutron Source (SNS). A 4 MW SNS is proposed to be built at the Oak Ridge National Laboratory with the first stage to be operative around 2006. It will have two target stations, which makes it possible with a single detector to perform a neutrino oscillation search at two different distances. Initial plans for the placement of the detector and the discovery potential of such a detector are discussed

  4. 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.

  5. Seismofocal zones and mid-ocean ridges - look outside of the plate paradigm

    Science.gov (United States)

    Anokhin, Vladimir; Kholmianskii, Mikhail

    2014-05-01

    Seismofocal zones and mid-ocean ridges - look outside of the plate paradigm Vladimir M. Anokhin, Mikhail A. Kholmianskii Configuration of the seismofocal zones (SFZ), visible in a real position of the focuses of earthquakes, has a significant step component (jagged) expressed by the presence of several sub-horizontal "seismoplanes", which concentrates focuses of earthquakes (depths 10, 35 km and other). Orientation of seismolines inside of SFZ tends to 4 main directions: 0-5 dgr, 120-145 dgr, 40-55 dgr, 85-90 dgr. These facts suggest significantly block, a terraced structure of the body of Benioff zone. The borders of blocks have orientation according directions regmatic net of the Earth. In accordance with this, SFZ can be presented as the most active segments of the border of the crossing: «continent-ocean», having the following properties: - block (terraced) structure; - in some sites - dive under the continental crust (in present time); - prevailing compression (in present time), perhaps, as the period of the oscillatory cycle; Infinite "subduction" in SFZ is unlikely. One of the areas where there is proof of concept of far "spreading" is the southernmost tip of the mid-oceanic Gakkel ridge in the Laptev sea (Arctic ocean). Here active "spreading" ridge normal approaches to the boundary of the continental crust - the shelf of the Laptev sea. On the shelf there are a number of subparallel NW grabens. NE fault zone Charlie, controlling the continental slope is established stepped fault without shift component. This means that the amount of extending of the offshore grabens does not significantly differ from the scale of spreading in the Gakkel ridge. However, the total spreads grabens (50-100 km) 6-10 times less than the width of the oceanic crust (600 km) in the surrounding area. Conclusion: the oceanic crust in the Laptev sea was formed mainly not due to "spreading". It is very likely that here was sinking and the processing of continental crust in the ocean

  6. Volcano-tectonic evolution of a linear volcanic ridge (Pico-Faial Ridge, Azores Triple Junction) assessed by paleomagnetic studies

    Science.gov (United States)

    Silva, Pedro F.; Henry, Bernard; Marques, Fernando O.; Hildenbrand, Anthony; Lopes, Ana; Madureira, Pedro; Madeira, José; Nunes, João C.; Roxerová, Zuzana

    2018-02-01

    The morphology of volcanic oceanic islands results from the interplay between constructive and destructive processes, and tectonics. In this study, the analysis of the paleomagnetic directions obtained on well-dated volcanic rocks is used as a tool to assess tilting related to tectonics and large-scale volcano instability along the Pico-Faial linear volcanic ridge (Azores Triple Junction, Central-North Atlantic). For this purpose, 530 specimens from 46 lava flows and one dyke from Pico and Faial islands were submitted to thermal and alternating magnetic fields demagnetizations. Detailed rock magnetic analyses, including thermomagnetic analyses and classical high magnetic field experiments revealed titanomagnetites with different Ti-content as the primary magnetic carrier, capable of recording stable remanent magnetizations. In both islands, the paleomagnetic analysis yields a Characteristic Remanent Magnetization, which presents island mean direction with normal and reversed polarities in agreement with the islands location and the age of the studied lava flows, indicating a primary thermo-remanent magnetization. Field observations and paleomagnetic data show that lava flows were emplaced on pre-existing slopes and were later affected by significant tilting. In Faial Island, magmatic inflation and normal faults making up an island-scale graben, can be responsible for the tilting. In Pico Island, inflation related to magma intrusion during flow emplacement can be at the origin of the inferred tilting, whereas gradual downward movement of the SE flank by slumping processes appears mostly translational.

  7. Normalization Ridge Regression in Practice I: Comparisons Between Ordinary Least Squares, Ridge Regression and Normalization Ridge Regression.

    Science.gov (United States)

    Bulcock, J. W.

    The problem of model estimation when the data are collinear was examined. Though the ridge regression (RR) outperforms ordinary least squares (OLS) regression in the presence of acute multicollinearity, it is not a problem free technique for reducing the variance of the estimates. It is a stochastic procedure when it should be nonstochastic and it…

  8. Fault Management Design Strategies

    Science.gov (United States)

    Day, John C.; Johnson, Stephen B.

    2014-01-01

    Development of dependable systems relies on the ability of the system to determine and respond to off-nominal system behavior. Specification and development of these fault management capabilities must be done in a structured and principled manner to improve our understanding of these systems, and to make significant gains in dependability (safety, reliability and availability). Prior work has described a fundamental taxonomy and theory of System Health Management (SHM), and of its operational subset, Fault Management (FM). This conceptual foundation provides a basis to develop framework to design and implement FM design strategies that protect mission objectives and account for system design limitations. Selection of an SHM strategy has implications for the functions required to perform the strategy, and it places constraints on the set of possible design solutions. The framework developed in this paper provides a rigorous and principled approach to classifying SHM strategies, as well as methods for determination and implementation of SHM strategies. An illustrative example is used to describe the application of the framework and the resulting benefits to system and FM design and dependability.

  9. Ridge regression estimator: combining unbiased and ordinary ridge regression methods of estimation

    Directory of Open Access Journals (Sweden)

    Sharad Damodar Gore

    2009-10-01

    Full Text Available Statistical literature has several methods for coping with multicollinearity. This paper introduces a new shrinkage estimator, called modified unbiased ridge (MUR. This estimator is obtained from unbiased ridge regression (URR in the same way that ordinary ridge regression (ORR is obtained from ordinary least squares (OLS. Properties of MUR are derived. Results on its matrix mean squared error (MMSE are obtained. MUR is compared with ORR and URR in terms of MMSE. These results are illustrated with an example based on data generated by Hoerl and Kennard (1975.

  10. Mid-late Holocene paleoseismicity of the eastern Clarence Fault, Marlborough, New Zealand

    International Nuclear Information System (INIS)

    Van Dissen, R.J.; Nicol, A.

    2009-01-01

    The middle Clarence valley, or eastern, section of the active Clarence Fault bounds the steep southeast flank of the Inland Kaikoura Range, Marlborough, New Zealand. This section of the fault extends c. 45 km northeastwards from its junction with the Elliott Fault to Mead Stream, where the active trace of the fault appears to abruptly end. Along the active trace, 41 separate right-lateral offsets of c. 3-40 m were recorded with uncertainties of 10-50% (mean 25%) using tape measurement of displaced topographic features (e.g., gully walls, landslide margins, and ridge crests). Single-event right-lateral displacements of 7 ± 2 m are inferred and indicate earthquake magnitudes of Mw 7.2-7.9. Probable rupture lengths have been in excess of 45 km, which suggests that rupture of the middle Clarence valley (eastern) section of the fault extended to the west onto the central Clarence and/or Elliott faults. Stream incision through the uphill-facing fault scarp at Ravine Stream and Dead Horse Gully has exposed progressively faulted peat and charcoal horizons. Elsewhere, there are several exposures of unfaulted sediments. Twelve radiocarbon samples dated from these horizons constrain the timing of the four most recent surface-rupture earthquakes on the Clarence Fault in the study area. The most recent surface rupture took place at c. 1700-1900 cal. yr BP (rounded to the nearest hundred years), with two surface ruptures since c. 3400 cal. yr BP, three since 6700 cal. yr BP, and most likely a fourth surface rupture at c. 6600-6900 cal. yr BP. These data suggest a recurrence interval for surface-rupture earthquakes of c. 1700 yr, and imply a lateral slip rate of c. 4 mm/yr (i.e., c. 7 m of slip every c. 1700 yr). (author). 45 refs., 9 figs., 3 tabs.

  11. Fault structure, properties and activity of the Makran Accretionary Prism and implications for seismogenic potential

    Science.gov (United States)

    Smith, G. L.; McNeill, L. C.; Henstock, T.; Bull, J. M.

    2011-12-01

    The Makran subduction zone is the widest accretionary prism in the world (~400km), generated by convergence between the Arabian and Eurasian tectonic plates. It represents a global end-member, with a 7km thick incoming sediment section. Accretionary prisms have traditionally been thought to be aseismic due to the presence of unconsolidated sediment and elevated basal pore pressures. The seismogenic potential of the Makran subduction zone is unclear, despite a Mw 8.1 earthquake in 1945 that may have been located on the plate boundary beneath the prism. In this study, a series of imbricate landward dipping (seaward verging) thrust faults have been interpreted across the submarine prism (outer 70 km) using over 6000km of industry multichannel seismic data and bathymetric data. A strong BSR (bottom simulating reflector) is present throughout the prism (excluding the far east). An unreflective décollement is interpreted from the geometry of the prism thrusts. Two major sedimentary units are identified in the input section, the lower of which contains the extension of the unreflective décollement surface. Between 60%-100% of the input section is currently being accreted. The geometry of piggy-back basin stratigraphy shows that the majority of thrusts, including those over 50km from the trench, are recently active. Landward thrusts show evidence for reactivation after periods of quiescence. Negative polarity fault plane reflectors are common in the frontal thrusts and in the eastern prism, where they may be related to increased fault activity and fluid expulsion, and are rarer in older landward thrusts. Significant NE-SW trending basement structures (The Murray Ridge and Little Murray Ridge) on the Arabian plate intersect the deformation front and affect sediment input to the subduction zone. Prism taper and structure are apparently primarily controlled by sediment supply and the secondary influence of subducting basement ridges. The thick, likely distal, sediment

  12. Bow tie methodology: a tool to enhance the visibility and understanding of nuclear safety cases

    International Nuclear Information System (INIS)

    Vannerem, Marc

    2013-01-01

    There is much common ground between the nuclear industry and other major hazard industries such as those subject to the Seveso II regulations, e.g. oil, gas and chemicals. They are all subject to legal requirements to identify and control hazards, and to demonstrate that all necessary measures have been taken to minimise risks posed by the site with regard to people and the environment. This places a requirement on the Operators of major hazard installations, whether nuclear or conventional, to understand and identify the hazards of their operations, the initiating events, the consequences, the prevention and mitigation measures. However, in the UK, nuclear and 'Seveso' type facilities seem to adopt a different approach to the presentation of their safety cases. Given the magnitude of the hazards, safety cases developed for nuclear fuel cycle facilities are rigorous, detailed and complex, which can have the effect of reducing the visibility of the key hazards and corresponding protective measures. In contrast, on installations in the oil and gas and chemical industries, a real attempt has been made over recent years to improve the visibility and accessibility of the safety case to all operating personnel, through the use of visual aids / diagrams. In particular, many Operators are choosing to use 'bow tie methodology', in which very simple overview diagrams are produced to illustrate, in a form understandable by all: - what the key hazards are; - the initiating events; - the consequences of an incident; - the barriers or 'Layers of Protection' which prevent an initiating event from developing into an incident; - the barriers or 'Layers of Defence' which mitigate the consequences of an incident, i.e. which prevent the incident from escalating into major consequences. The bow tie method is one of a number of methodologies that can be used to make safety cases more accessible. It is used in this paper to illustrate ways to

  13. Source parameters of the Bay of Bengal earthquake of 21 May 2014 and related seismotectonics of 85°E and 90°E ridges

    Science.gov (United States)

    Prakash, Rajesh; Prajapati, Sanjay Kumar; Srivastava, Hari Narain

    2018-01-01

    Source parameters of the Bay of Bengal earthquake of 21 May 2014 have been studied using full waveform inversion. Its source mechanism thus determined the orientation of the strike slip faulting as NW-SE/NE-SW. The occurrence of past earthquakes along the NE-SW nodal plane suggested its preference as the main fault which could result from the transmission of stresses from the Indian plate boundary. High stress drop of this earthquake (216 bar) is attributed to its location in the intraplate region, strike slip faulting and focus in the colder upper mantle. Comparison of the stress drop of deeper focus Hindukush earthquakes with that of the Bay of Bengal earthquake showed a smaller felt radius due to fractured lithosphere in the Himalayas vis-a-vis more efficient propagation of seismic waves in the peninsular region from the source region of this recent earthquake. The seismological evidence presented for the 85°E and 90°E ridges shows the predominance of strike slip faulting with thrusting on both the ridges. Integrating their source mechanism with that of the May 2014 earthquake, it could be inferred that the Bay of Bengal region (excluding Andaman Sumatra subduction zone) is characterised predominantly by strike slip faulting in the region north of latitude 20°N and strike slip with thrusting in the remaining portion.

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

    Czech Academy of Sciences Publication Activity Database

    Zajaček, Michal; Eckart, A.; Karas, Vladimír; Kunneriath, Devaky; Shahzamanian, B.; Sabha, N.; Muzic, K.; Valencia-S, M.

    2016-01-01

    Roč. 455, č. 2 (2016), s. 1257-1274 ISSN 0035-8711 R&D Projects: GA ČR(CZ) GC13-00070J Institutional research plan: CEZ:AV0Z1003909 Institutional support: RVO:67985815 Keywords : galactic centre * black hole * bow-shock Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.961, year: 2016

  15. Atelier Bow-Wow on the Representation of Behaviorology: Yosiharu Tsukamoto in conversation with Anne Elisabeth Toft and Christina Capetillo

    DEFF Research Database (Denmark)

    Toft, Anne Elisabeth; Capetillo, Christina

    2015-01-01

    Yoshiharu Tsukamoto discussing the representational practices of Atelier Bow-Wow and its work on “Behaviorology”: How do you represent the seemingly un-representable? How do you depict and illustrate what is not tangible? How do you represent social practices, time-based processes, situations...

  16. 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...

  17. Accelerometer having integral fault null

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-08-01

    An improved accelerometer is introduced. It comprises a transducer responsive to vibration in machinery which produces an electrical signal related to the magnitude and frequency of the vibration; and a decoding circuit responsive to the transducer signal which produces a first fault signal to produce a second fault signal in which ground shift effects are nullified.

  18. Identification of the nonlinear excitation force acting on a bowed string using the dynamical responses at remote locations

    International Nuclear Information System (INIS)

    Debut, V.; Antunes, J.; Delaune, X.

    2010-01-01

    For achieving realistic numerical simulations of bowed string instruments, based on physical modeling, a good understanding of the actual friction interaction phenomena is of great importance. Most work published in the field including our own has assumed that bow/string frictional forces behave according to the classical Coulomb stick-slip model, with an empirical velocity-dependent sliding friction coefficient. Indeed, the basic self-excited string motions (such as the Helmholtz regime) are well captured using such friction model. However, recent work has shown that the tribological behavior of the bow/string rosin interface is rather complex, therefore the basic velocity-dependent Coulomb model may be an over-simplistic representation of the friction force. More specifically, it was suggested that a more accurate model of the interaction force can be achieved by coupling the system dynamical equations with a thermal model which encapsulates the complex interface phenomena. In spite of the interesting work performed by Askenfelt, a direct measurement of the actual dynamical friction forces without disturbing the string motion is quite difficult. Therefore, in this work we develop a modal-based identification technique making use of inverse methods and optimization techniques, which enables the identification of the interface force, as well as the string self-excited motion, from the dynamical reactions measured at the string end supports. The method gives convincing results using simulated data originated from nonlinear computations of a bowed string. Furthermore, in cases where the force identifications are very sensitive to errors in the transfer function modal parameters, we suggest a method to improve the modal frequencies used for the identifications. Preliminary experimental results obtained using a basic bowing device, by which the string is excited with the stick of the bow, are then presented. Our identifications, from the two dynamical string reactions

  19. Internal doses in Oak Ridge. The Internet beams

    International Nuclear Information System (INIS)

    Passchier, W.F.

    1997-01-01

    A brief overview is given of the information, presented by the Radiation Internal Dose Information Center (RIDIC) of the Oak Ridge Associated Universities in Oak Ridge, TN, USA, via Internet (www.orau.gov/ehsd/ridic.htm)

  20. Efficiency of local surface plasmon polariton excitation on ridges

    DEFF Research Database (Denmark)

    Radko, Ilya; Bozhevolnyi, Sergey I.; Boltasseva, Alexandra

    2008-01-01

    We investigate experimentally and numerically the efficiency of surface plasmon polariton excitation by a focused laser beam using gold ridges. The dependence of the efficiency on geometrical parameters of ridges and wavelength dependence are examined. The experimental measurements accomplished...

  1. DEVELOPMENT OF A RIDGE PROFILE WEEDER

    African Journals Online (AJOL)

    ES Obe

    1980-03-01

    driven rotating horizontal short shaft which is connected by universal joints to two gangs of rotary hoe weeders. With the short shaft nearly at the bottom of a furrow between two ridges, the gangs of weeders lie on the sides of ...

  2. Oak Ridge Reservation Waste Management Plan

    International Nuclear Information System (INIS)

    Turner, J.W.

    1995-02-01

    This report presents the waste management plan for the Oak Ridge Reservation facilities. The primary purpose is to convey what facilities are being used to manage wastes, what forces are acting to change current waste management systems, and what plans are in store for the coming fiscal year

  3. Remedial Investigation Work Plan for Chestnut Ridge Operable Unit 1 (Chestnut Ridge Security Pits) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    This Remedial Investigation (RI) Work Plan specifically addresses Chestnut Ridge Operable Unit 1, (OU1) which consists of the Chestnut Ridge Security Pits (CRSP). The CRSP are located {approximately}800 ft southeast of the central portion of the Y-12 Plant atop Chestnut Ridge, which is bounded to the northwest by Bear Creek Valley and to the southeast by Bethel Valley. Operated from 1973 to 1988, the CRSP consisted of a series of trenches used for the disposal of classified hazardous and nonhazardous waste materials. Disposal of hazardous waste materials was discontinued in December 1984, while nonhazardous waste disposal ended on November 8, 1988. An RI is being conducted at this site in response to CERCLA regulations. The overall objectives of the RI are to collect data necessary to evaluate the nature and extent of contaminants of concern (COC), support an ecological risk assessment (ERA) and a human health risk assessment (HHRA), support the evaluation of remedial alternatives, and ultimately develop a Record of Decision for the site. The purpose of this Work Plan is to outline RI activities necessary to define the nature and extent of suspected contaminants at Chestnut Ridge OU1. Potential migration pathways also will be investigated. Data collected during the RI will be used to evaluate the overall risk posed to human health and the environment by OU1.

  4. Alveolar ridge augmentation by osteoinduction in rats

    DEFF Research Database (Denmark)

    Pinholt, E M; Bang, G; Haanaes, H R

    1990-01-01

    The purpose of this study was to evaluate bone substitutes for alveolar ridge augmentation by osteoinduction. Allogenic, demineralized, and lyophilized dentin and bone was tested for osteoinductive properties in order to establish an experimental model for further studies. Implantations were perf...

  5. Oak Ridge Reservation Waste Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.W. [ed.

    1995-02-01

    This report presents the waste management plan for the Oak Ridge Reservation facilities. The primary purpose is to convey what facilities are being used to manage wastes, what forces are acting to change current waste management systems, and what plans are in store for the coming fiscal year.

  6. 25 MV tandem accelerator at Oak Ridge

    International Nuclear Information System (INIS)

    Jones, C.M.

    1980-01-01

    A new heavy-ion accelerator facility is under construction at the Oak Ridge National Laboratory. A brief description of the scope and status of this project is presented with emphasis on the first operational experience with the 25 MV tandem accelerator

  7. Oak Ridge reservation land-use plan

    Energy Technology Data Exchange (ETDEWEB)

    Bibb, W. R.; Hardin, T. H.; Hawkins, C. C.; Johnson, W. A.; Peitzsch, F. C.; Scott, T. H.; Theisen, M. R.; Tuck, S. C.

    1980-03-01

    This study establishes a basis for long-range land-use planning to accommodate both present and projected DOE program requirements in Oak Ridge. In addition to technological requirements, this land-use plan incorporates in-depth ecological concepts that recognize multiple uses of land as a viable option. Neither environmental research nor technological operations need to be mutually exclusive in all instances. Unique biological areas, as well as rare and endangered species, need to be protected, and human and environmental health and safety must be maintained. The plan is based on the concept that the primary use of DOE land resources must be to implement the overall DOE mission in Oak Ridge. This document, along with the base map and overlay maps, provides a reasonably detailed description of the DOE Oak Ridge land resources and of the current and potential uses of the land. A description of the land characteristics, including geomorphology, agricultural productivity and soils, water courses, vegetation, and terrestrial and aquatic animal habitats, is presented to serve as a resource document. Essentially all DOE land in the Oak Ridge area is being fully used for ongoing DOE programs or has been set aside as protected areas.

  8. Remedial Investigation Work Plan for Chestnut Ridge Operable Unit 1 (Chestnut Ridge Security Pits) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1993-09-01

    This Remedial Investigation (RI) Work Plan specifically addresses Chestnut Ridge Operable Unit 1, (OU1) which consists of the Chestnut Ridge Security Pits (CRSP). The CRSP are located ∼800 ft southeast of the central portion of the Y-12 Plant atop Chestnut Ridge, which is bounded to the northwest by Bear Creek Valley and to the southeast by Bethel Valley. Operated from 1973 to 1988, the CRSP consisted of a series of trenches used for the disposal of classified hazardous and nonhazardous waste materials. Disposal of hazardous waste materials was discontinued in December 1984, while nonhazardous waste disposal ended on November 8, 1988. An RI is being conducted at this site in response to CERCLA regulations. The overall objectives of the RI are to collect data necessary to evaluate the nature and extent of contaminants of concern (COC), support an ecological risk assessment (ERA) and a human health risk assessment (HHRA), support the evaluation of remedial alternatives, and ultimately develop a Record of Decision for the site. The purpose of this Work Plan is to outline RI activities necessary to define the nature and extent of suspected contaminants at Chestnut Ridge OU1. Potential migration pathways also will be investigated. Data collected during the RI will be used to evaluate the overall risk posed to human health and the environment by OU1

  9. Petrography of basalts from the Carlsberg ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D.

    Petrographic characteristics of basalts collected from a segment of the Carlsberg Ridge (lat. 3 degrees 35'N to 3 degrees 41'N; long. 64 degrees 05'E to 64 degrees 09'E) show typical pillow lava zonations with variable concentrations of plagioclase...

  10. An adaptive and tacholess order analysis method based on enhanced empirical wavelet transform for fault detection of bearings with varying speeds

    Science.gov (United States)

    Hu, Yue; Tu, Xiaotong; Li, Fucai; Li, Hongguang; Meng, Guang

    2017-11-01

    The order tracking method based on time-frequency representation is regarded as an effective tool for fault detection of bearings with varying rotating speeds. In the traditional order tracking methods, a tachometer is required to obtain the instantaneous speed which is hardly satisfied in practice due to the technical and economical limitations. Some tacholess order tracking methods have been developed in recent years. In these methods, the instantaneous frequency ridge extraction is one of the most important parts. However, the current ridge extraction methods are sensitive to noise and may easily get trapped in a local optimum. Due to the presence of noise and other unrelated components of the signal, bearing fault features are difficult to be detected from the envelope spectrum or envelope order spectrum. To overcome the abovementioned drawbacks, an adaptive and tacholess order analysis method is proposed in this paper. In this method, a novel ridge extraction algorithm based on dynamic path optimization is adopted to estimate the instantaneous frequency. This algorithm can overcome the shortcomings of the current ridge extraction algorithms. Meanwhile, the enhanced empirical wavelet transform (EEWT) algorithm is applied to extract the bearing fault features. Both simulated and experimental results demonstrate that the proposed method is robust to noise and effective for bearing fault detection under variable speed conditions.

  11. Fault isolatability conditions for linear systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Henrik

    2006-01-01

    In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...... the faults have occurred. The last step is a fault isolation (FI) of the faults occurring in a specific fault set, i.e. equivalent with the standard FI step. A simple example demonstrates how to turn the algebraic necessary and sufficient conditions into explicit algorithms for designing filter banks, which...

  12. ESR dating of the fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon

    2005-01-01

    We carried out ESR dating of fault rocks collected near the nuclear reactor. The Upcheon fault zone is exposed close to the Ulzin nuclear reactor. The space-time pattern of fault activity on the Upcheon fault deduced from ESR dating of fault gouge can be summarised as follows : this fault zone was reactivated between fault breccia derived from Cretaceous sandstone and tertiary volcanic sedimentary rocks about 2 Ma, 1.5 Ma and 1 Ma ago. After those movements, the Upcheon fault was reactivated between Cretaceous sandstone and fault breccia zone about 800 ka ago. This fault zone was reactivated again between fault breccia derived form Cretaceous sandstone and Tertiary volcanic sedimentary rocks about 650 ka and after 125 ka ago. These data suggest that the long-term(200-500 k.y.) cyclic fault activity of the Upcheon fault zone continued into the Pleistocene. In the Ulzin area, ESR dates from the NW and EW trend faults range from 800 ka to 600 ka NE and EW trend faults were reactivated about between 200 ka and 300 ka ago. On the other hand, ESR date of the NS trend fault is about 400 ka and 50 ka. Results of this research suggest the fault activity near the Ulzin nuclear reactor fault activity continued into the Pleistocene. One ESR date near the Youngkwang nuclear reactor is 200 ka

  13. The geometry of the active strike-slip El Tigre Fault, Precordillera of San Juan, Central-Western Argentina: integrating resistivity surveys with structural and geomorphological data

    Science.gov (United States)

    Fazzito, Sabrina Y.; Cortés, José M.; Rapalini, Augusto E.; Terrizzano, Carla M.

    2013-07-01

    The geometry and related geomorphological features of the right-lateral strike-slip El Tigre Fault, one of the main morphostructural discontinuities in the Central-Western Precordillera of Argentina, were investigated. Achievements of this survey include: recognition of structural and geometrical discontinuities along the fault trace, identification and classification of landforms associated with local transpressional and transtensional sectors, observation of significant changes in the fault strike and detection of right and left bends of different wavelength. In the Central Segment of the El Tigre Fault, 2D electrical resistivity tomography surveys were carried out across the fault zone. The resistivity imaging permitted to infer the orientation of the main fault surface, the presence of blind fault branches along the fault zone, tectonic tilting of the Quaternary sedimentary cover, subsurface structure of pressure ridges and depth to the water table. Based on this information, it is possible to characterize the El Tigre Fault also as an important hydro-geological barrier. Our survey shows that the main fault surface changes along different segments from a high-angle to a subvertical setting whilst the vertical-slip component is either reverse or normal, depending on the local transpressive or transtensive regime induced by major bends along the trace. These local variations are expressed as sections of a few kilometres in length with relatively homogeneous behaviour and frequently separated by oblique or transversal structures.

  14. The Northern Central Indian Ridge: Geology and tectonics of fracture zones-dominated spreading ridge segments

    Digital Repository Service at National Institute of Oceanography (India)

    Drolia, R.K.; Iyer, S.D.; Chakraborty, B.; Kodagali, V.N.; Ray, Dwijesh; Misra, S.; Andrade, R.; Sarma, K.V.L.N.S.; Rajasekhar, R.P.; Mukhopadhyay, R.

    Multi-beam and single-beam bathymetric, gravity and magnetic data, across seven ridge segments (length varying between 37 and 84 km), offset by six transform discontinuities (ranging in dislocation length between 48 and 344 km) of the Northern...

  15. A revisit to vityaz transform fault area, Central Indian Ridge: Isotopic evidence of probable hydrothermal activity.

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Banerjee, R.; Xiao, Y.K.

    at the Institute of Salt Lakes, China by +ve thermal ionisation mass spectrometry of Cs2BO4+ and Cs2Cl+ ions respectively, using a VG 354 model TIMS [14]. The measured isotopic ratios were expressed as del values relative to their standard reference materials.... 37.5 38 38.5 39 39.5 40 Del 11B 2000 1600 1200 800 400 0 W at er d ep th (m ) -0.2 0 0.2 0.4 0.6 0.8 Del 37Cl 2000 1600 1200 800 400 0 Figure 2: Vertical profiles of δ11B and δ37Cl in water column at Stn.VM3 in the CIR. Stn. No. Latitude Longitude...

  16. Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

    Directory of Open Access Journals (Sweden)

    Fan Xiao

    2015-09-01

    Full Text Available During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive and negative sequence components. In these cases, the dynamic response of a rotor-side converter (RSC and the notch filters have a large influence on the fault current characteristics of the DFIG. In this paper, the influence of the notch filters on the proportional integral (PI parameters is discussed and the simplified calculation models of the rotor current are established. Then, the dynamic performance of the stator flux linkage under asymmetrical fault conditions is also analyzed. Based on this, the fault characteristics of the stator current under asymmetrical fault conditions are studied and the corresponding analytical expressions of the stator fault current are obtained. Finally, digital simulation results validate the analytical results. The research results are helpful to meet the requirements of a practical short-circuit calculation and the construction of a relaying protection system for the power grid with penetration of DFIGs.

  17. 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.

  18. Short term memory bowing effect is consistent with presentation rate dependent decay.

    Science.gov (United States)

    Tarnow, Eugen

    2010-12-01

    I reanalyze the free recall data of Murdock, J Exp Psychol 64(5):482-488 (1962) and Murdock and Okada, J Verbal Learn and Verbal Behav 86:263-267 (1970) which show the famous bowing effect in which initial and recent items are recalled better than intermediate items (primacy and recency effects). Recent item recall probabilities follow a logarithmic decay with time of recall consistent with the tagging/retagging theory. The slope of the decay increases with increasing presentation rate. The initial items, with an effectively low presentation rate, decay with the slowest logarithmic slope, explaining the primacy effect. The finding that presentation rate limits the duration of short term memory suggests a basis for memory loss in busy adults, for the importance of slow music practice, for long term memory deficiencies for people with attention deficits who may be artificially increasing the presentation rates of their surroundings. A well-defined, quantitative measure of the primacy effect is introduced.

  19. ULF/ELF electromagnetic waves associated with the quasi-perpendicular earth's bow shock crossings

    International Nuclear Information System (INIS)

    Nozdrachev, M.N.; Petrukovich, A.A.

    1992-01-01

    The present paper is dedicated to the analysis of electromagnetic turbulence in the frequency range 0.1-75 Hz, associated with crossing of Earth's Bow Shock recorded by the Prognoz-8 and -10 satellites. The quasimonochromatic waves are identified in the shock transition region. Their frequencies, laying in the range from 2 Hz to 6 Hz upstream the shock ramp shift to the values less than 1 Hz in the downstream region. The amplitudes of these narrow emissions are high enough to provide the dissipation in the flow of the solar wind plasma. It is argued that spectra shapes in this frequency range 0.1-75 Hz are strongly affected by the Doppler shift

  20. Ion acceleration at the earth's bow shock: A review of observations in the upstream region

    International Nuclear Information System (INIS)

    Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

    1979-01-01

    Positive ions are accelerated at or near the earth's bow shock and propagate into the upstream region. Two distinctly different population of these ions, distinguished by their greatly different spectral and angular widths, can be identified there. The type of ion population observed in the upstream region is strongly correlated with the presence or absence of long-period compresive waves in the solar wind. Very few ions are accelerated in the vicinity of the shock to energies much above about 100 keV. It is not yet clear whether the most energetic ions (i.e. those near 100 keV) are accelerated at the shock or in the broad disturbed region upstream from the shock. In either case stochastic acceleration by turbulent electrostatic fields seems to be the most viable candidate for the acceleration of the most energetic particles

  1. First-order Fermi acceleration of the diffuse ion population near the earth's bow shock

    Science.gov (United States)

    Forman, M. A.

    1981-01-01

    The flux of 30-65 keV particles observed by the ISEE-3 200 earth radii upstream is shown to be an upstream escape of the energetic ions in the earth's bow shock. A formal solution to the transport equation for the distribution function of energetic particles upstream from an isotropic monoenergetic source of particles/sq cm at a plane shock where the plasma changes speed is found, and escape conditions are defined. The efficiency of the acceleration is calculated to depend on the charge/particle, and fluxes near and far upstream of the shock are described analytically. Any model which takes into account shock acceleration by diffusive scattering with significant escape losses produces the observed spectrum close to the shock. The escape loss upstream is demonstrated to control the spectrum and the variation of flux and anisotropy with distance from the shock.

  2. 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

    2013-04-05

    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.

  3. Electron bulk acceleration and thermalization at Earth's quasi-perpendicular bow shock

    Science.gov (United States)

    Chen, L.-J.; Wang, S.; Wilson, L. B., III; Schwartz, S. J.; Bessho, N.; Moore, T. E.; Gershman, D. J.; Giles, B. L.; Malaspina, D. M.; Wilder, F. D.; Ergun, R. E.; Hesse, M.; Lai, H.; Russell, C. T.; Strangeway, R. J.; Torbert, R. B.; Vinas, A. F.-; Burch, J. L.; Lee, S.; Pollock, C.; Dorelli, J.; Paterson, W. R.; Ahmadi, N.; Goodrich, K. A.; Lavraud, B.; Le Contel, O.; Khotyaintsev, Yu. V.; Lindqvist, P.-A.; Boardsen, S.; Wei, H.; Le, A.; Avanov, L. A.

    2018-05-01

    Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.

  4. Method for measuring violin sound radiation based on bowed glissandi and its application to sound synthesis.

    Science.gov (United States)

    Perez Carrillo, Alfonso; Bonada, Jordi; Patynen, Jukka; Valimaki, Vesa

    2011-08-01

    This work presents a method for measuring and computing violin-body directional frequency responses, which are used for violin sound synthesis. The approach is based on a frame-weighted deconvolution of excitation and response signals. The excitation, consisting of bowed glissandi, is measured with piezoelectric transducers built into the bridge. Radiation responses are recorded in an anechoic chamber with multiple microphones placed at different angles around the violin. The proposed deconvolution algorithm computes impulse responses that, when convolved with any source signal (captured with the same transducer), produce a highly realistic violin sound very similar to that of a microphone recording. The use of motion sensors allows for tracking violin movements. Combining this information with the directional responses and using a dynamic convolution algorithm, helps to improve the listening experience by incorporating the violinist motion effect in stereo.

  5. High time resolution characteristics of intermediate ion distributions upstream of the earth's bow shock

    Science.gov (United States)

    Potter, D. W.

    1985-01-01

    High time resolution particle data upstream of the bow shock during time intervals that have been identified as having intermediate ion distributions often show high amplitude oscillations in the ion fluxes of energy 2 and 6 keV. These ion oscillations, observed with the particle instruments of the University of California, Berkeley, on the ISEE 1 and 2 spacecraft, are at the same frequency (about 0.04 Hz) as the magnetic field oscillations. Typically, the 6-keV ion flux increases then the 2-keV flux increases followed by a decrease in the 2-keV flux and then the 6-keV flux decreases. This process repeats many times. Although there is no entirely satisfactory explanation, the presence of these ion flux oscillations suggests that distributions often are misidentified as intermediate ion distributions.

  6. Nowcasting and forecasting of the magnetopause and bow shock—A status update

    Science.gov (United States)

    Petrinec, S. M.; Redmon, R. J.; Rastaetter, L.

    2017-01-01

    There has long been interest in knowing the shape and location of the Earth's magnetopause and of the standing fast-mode bow shock upstream of the Earth's magnetosphere. This quest for knowledge spans both the research and operations arenas. Pertinent to the latter, nowcasting and near-term forecasting are important for determining the extent to which the magnetosphere is compressed or expanded due to the influence of the solar wind bulk plasma and fields and the coupling to other magnetosphere-ionosphere processes with possible effects on assets. This article provides an update to a previous article on the same topic published 15 years earlier, with focus on studies that have been conducted, the current status of nowcasting and forecasting of geophysical boundaries, and future endeavors.

  7. A Multi-wavelength Study of an Isolated MSP Bow Shock

    Science.gov (United States)

    Romani, Roger W.; Slane, Patrick; Green, Andrew

    2017-08-01

    PSR J2124-3358 is the only single MSP known to sport an Halpha bow shock. This shock, now also seen in the UV, encloses an unusual X-ray pulsar wind nebula (PWN) with a long off-axis trail. Combining the X-ray and UV images with AAT/KOALA integral field spectroscopy of the Halpha emission, we have an unusually complete picture of the pulsar's (101 km/s transverse) motion and the latitudinal distribution of its wind flux. These images reveal the 3-D orientation of a hard-spectrum PWN jet and a softer equatorial outflow. Within the context of a thin shock model, we can constrain the total energy output of the pulsar and the neutron star moment of inertia. The IFU spectra show extreme Balmer dominance, which also constrains the nature of the UV shock emission.

  8. Ion acceleration at the earth's bow shock: a review of observations in the upstream region

    International Nuclear Information System (INIS)

    Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

    1979-01-01

    Positive ions are accelerated at or near the earth's bow shock and propagate into the upstream region. Two distinctly different populations of these ions, distinguished by their greatly different spectral and angular widths, can be identified there. The type of ion population observed in the upstream region is strongly correlated with the presence or absence of long-period compressive waves in the solar wind. Very few ions are accelerated in the vicinity of the shock to energies much above about 100 keV. It is not yet clear whether the most energetic ions (i.e., those near 100 keV) are accelerated at the shock or in broad disturbed region upstream from the shock. In either case stochastic acceleration by turbulent electrostatic fields seems to be the most viable candidate for the acceleration of the most energetic particles

  9. Arc fault detection system

    Science.gov (United States)

    Jha, K.N.

    1999-05-18

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  10. Arc fault detection system

    Science.gov (United States)

    Jha, Kamal N.

    1999-01-01

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

  11. Probabilistic assessment of faults

    International Nuclear Information System (INIS)

    Foden, R.W.

    1987-01-01

    Probabilistic safety analysis (PSA) is the process by which the probability (or frequency of occurrence) of reactor fault conditions which could lead to unacceptable consequences is assessed. The basic objective of a PSA is to allow a judgement to be made as to whether or not the principal probabilistic requirement is satisfied. It also gives insights into the reliability of the plant which can be used to identify possible improvements. This is explained in the article. The scope of a PSA and the PSA performed by the National Nuclear Corporation (NNC) for the Heysham II and Torness AGRs and Sizewell-B PWR are discussed. The NNC methods for hazards, common cause failure and operator error are mentioned. (UK)

  12. Design assessment for the Bethel Valley FFA Upgrades at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1995-09-01

    This report describes the proposed upgrades to Building 3025 and the Evaporator Area at Oak Ridge National Laboratory. Design assessments, specifications and drawings are provided. Building 3025 is a general purpose research facility utilized by the Materials and Ceramics Division to conduct research on irradiated materials. The Evaporator Area, building 2531, serves as the collection point for all low-level liquid wastes generated at the Oak Ridge National Laboratory

  13. 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.

  14. 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 fBi

  15. 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.

  16. 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.

  17. Injection and acceleration of H+ and He2+ at Earth's bow shock

    Directory of Open Access Journals (Sweden)

    K.-H. Trattner

    Full Text Available We have performed a number of one-dimensional hybrid simulations (particle ions, massless electron fluid of quasi-parallel collisionless shocks in order to investigate the injection and subsequent acceleration of part of the solar wind ions at the Earth's bow shock. The shocks propagate into a medium containing magnetic fluctuations, which are initially superimposed on the background field, as well as generated or enhanced by the electromagnetic ion/ion beam instability between the solar wind and backstreaming ions. In order to study the mass (M and charge (Q dependence of the acceleration process He2+ is included self-consistently. The upstream differential intensity spectra of H+ and He2+ can be well represented by exponentials in energy. The e-folding energy Ec is a function of time: Ec increases with time. Furthermore the e-folding energy (normalized to the shock ramming energy Ep increases with increasing Alfvén Mach number of the shock and with increasing fluctuation level of the initially superimposed turbulence. When backstreaming ions leave the shock after their first encounter they exhibit already a spectrum which extends to more than ten times the shock ramming energy and which is ordered in energy per charge. From the injection spectrum it is concluded that leakage of heated downstream particles does not contribute to ion injection. Acceleration models that permit thermal particles to scatter like the non-thermal population do not describe the correct physics.Key words. Interplanetary physics (planetary bow shocks · Space plasma physics (charged particle motion and acceleration; numerical simulation studies

  18. Injection and acceleration of H+ and He2+ at Earth's bow shock

    Directory of Open Access Journals (Sweden)

    M. Scholer

    1999-05-01

    Full Text Available We have performed a number of one-dimensional hybrid simulations (particle ions, massless electron fluid of quasi-parallel collisionless shocks in order to investigate the injection and subsequent acceleration of part of the solar wind ions at the Earth's bow shock. The shocks propagate into a medium containing magnetic fluctuations, which are initially superimposed on the background field, as well as generated or enhanced by the electromagnetic ion/ion beam instability between the solar wind and backstreaming ions. In order to study the mass (M and charge (Q dependence of the acceleration process He2+ is included self-consistently. The upstream differential intensity spectra of H+ and He2+ can be well represented by exponentials in energy. The e-folding energy Ec is a function of time: Ec increases with time. Furthermore the e-folding energy (normalized to the shock ramming energy Ep increases with increasing Alfvén Mach number of the shock and with increasing fluctuation level of the initially superimposed turbulence. When backstreaming ions leave the shock after their first encounter they exhibit already a spectrum which extends to more than ten times the shock ramming energy and which is ordered in energy per charge. From the injection spectrum it is concluded that leakage of heated downstream particles does not contribute to ion injection. Acceleration models that permit thermal particles to scatter like the non-thermal population do not describe the correct physics.Key words. Interplanetary physics (planetary bow shocks · Space plasma physics (charged particle motion and acceleration; numerical simulation studies

  19. Plasma and wave properties downstream of Martian bow shock: Hybrid simulations and MAVEN observations

    Science.gov (United States)

    Dong, Chuanfei; Winske, Dan; Cowee, Misa; Bougher, Stephen W.; Andersson, Laila; Connerney, Jack; Epley, Jared; Ergun, Robert; McFadden, James P.; Ma, Yingjuan; Toth, Gabor; Curry, Shannon; Nagy, Andrew; Jakosky, Bruce

    2015-04-01

    Two-dimensional hybrid simulation codes are employed to investigate the kinetic properties of plasmas and waves downstream of the Martian bow shock. The simulations are two-dimensional in space but three dimensional in field and velocity components. Simulations show that ion cyclotron waves are generated by temperature anisotropy resulting from the reflected protons around the Martian bow shock. These proton cyclotron waves could propagate downward into the Martian ionosphere and are expected to heat the O+ layer peaked from 250 to 300 km due to the wave-particle interaction. The proton cyclotron wave heating is anticipated to be a significant source of energy into the thermosphere, which impacts atmospheric escape rates. The simulation results show that the specific dayside heating altitude depends on the Martian crustal field orientations, solar cycles and seasonal variations since both the cyclotron resonance condition and the non/sub-resonant stochastic heating threshold depend on the ambient magnetic field strength. The dayside magnetic field profiles for different crustal field orientation, solar cycle and seasonal variations are adopted from the BATS-R-US Mars multi-fluid MHD model. The simulation results, however, show that the heating of O+ via proton cyclotron wave resonant interaction is not likely in the relatively weak crustal field region, based on our simplified model. This indicates that either the drift motion resulted from the transport of ionospheric O+, or the non/sub-resonant stochastic heating mechanism are important to explain the heating of Martian O+ layer. We will investigate this further by comparing the simulation results with the available MAVEN data. These simulated ion cyclotron waves are important to explain the heating of Martian O+ layer and have significant implications for future observations.

  20. Some improved classification-based ridge parameter of Hoerl and ...

    African Journals Online (AJOL)

    Some improved classification-based ridge parameter of Hoerl and Kennard estimation techniques. ... This assumption is often violated and Ridge Regression estimator introduced by [2]has been identified to be more efficient than ordinary least square (OLS) in handling it. However, it requires a ridge parameter, K, of which ...

  1. Does the lateral intercondylar ridge disappear in ACL deficient patients?

    NARCIS (Netherlands)

    van Eck, C.F.; Martins, C.A.Q.; Vyas, S.M.; Celentano, U.; van Dijk, C.N.; Fu, F.H.

    2010-01-01

    The aim of this study was to determine whether there is a difference in the presence of the lateral intercondylar ridge and the lateral bifurcate ridge between patients with sub-acute and chronic ACL injuries. We hypothesized that the ridges would be present less often with chronic ACL deficiency.

  2. Seismic Velocity Variation and Evolution of the Upper Oceanic Crust across the Mid-Atlantic Ridge at 1.3°S

    Science.gov (United States)

    Jian, H.; Singh, S. C.

    2017-12-01

    The oceanic crust that covers >70% of the solid earth is formed at mid-ocean ridges, but get modified as it ages. Understanding the evolution of oceanic crust requires investigations of crustal structures that extend from zero-age on the ridge axis to old crust. In this study, we analyze a part of a 2000-km-long seismic transect that crosses the Mid-Atlantic Ridge segment at 1.3°S, south of the Chain transform fault. The seismic data were acquired using a 12-km-long multi-sensor streamer and dense air-gun shots. Using a combination of downward continuation and seismic tomography methods, we have derived a high-resolution upper crustal velocity structure down to 2-2.5 km depth below the seafloor, from the ridge axis to 3.5 Ma on both sides of the ridge axis. The results demonstrate that velocities increase at all depths in the upper crust as the crust ages, suggesting that hydrothermal precipitations seal the upper crustal pore spaces. This effect is most significant in layer 2A, causing a velocity increase of 0.5-1 km/s after 1-1.5 Ma, beyond which the velocity increase is very small. Furthermore, the results exhibit a significant decrease in both the frequency and amplitude of the low-velocity anomalies associated with faults beyond 1-1.5 Ma, when faults become inactive, suggesting a linkage between the sealing of fault space and the extinction of hydrothermal activity. Besides, the off-axis velocities are systematically higher on the eastern side of the ridge axis compared to on the western side, suggesting that a higher hydrothermal activity should exist on the outside-corner ridge flank than on the inside-corner flank. While the tomography results shown here cover 0-3.5 Ma crust, the ongoing research will further extend the study area to older crust and also incorporating pre-stack migration and full waveform inversion methods to improve the seismic structure.

  3. Structure and Dynamics of the Southeast Indian Ridge and Off-axis Volcanism, 129°E to 140°E: Preliminary Results of the STORM Cruise

    Science.gov (United States)

    Maia, M.; Briais, A.; Barrere, F.; Boulart, C.; Ceuleneer, G.; Ferreira, N.; Hanan, B. B.; Hemond, C.; MacLeod, S.; Maillard, A. L.; Merkuryev, S. A.; Park, S. H.; Revillon, S.; Ruellan, E.; Schohn, A.; Watson, S. J.; Yang, Y. S.

    2015-12-01

    We present observations of the South-East Indian Ridge (SEIR) collected during the STORM cruise (South Tasmania Ocean Ridge and Mantle) on the N/O L'Atalante early 2015. The SEIR between Australia and Antarctica displays large variations of axial morphology despite an almost constant intermediate spreading rate. The Australia-Antarctic Discordance (AAD) between 120°E and 128°E is a section of the mid-ocean ridge where the magma budget is abnormally low, and which marks the boundary between Indian and Pacific mantle domains with distinct geochemical isotopic compositions. The STORM project focuses on the area east of the discordance from 128 to 140°E, where gravity highs observed on satellite-derived maps of the flanks of the SEIR reveal numerous volcanic seamounts. A major objective of the STORM cruise was to test the hypothesis of a mantle flow from the Pacific to the Indian domains. We collected multibeam bathymetry and magnetic data between 136 and 138°E to map off-axis volcanic ridges up to 10 Ma-old crust. We mapped the SEIR axis between 129 and 140°E, and the northern part of the George V transform fault. We collected rock samples on seamounts and in the transform fault, basaltic glass samples along the ridge axis, and near-bottom samples and in-situ measurements in the water column. Our observations reveal that the off-axis seamounts form near the SEIR axis, and are not associated to off-axis deformation of the ocean floor. They show a general shallowing of the ridge axis from the AAD to the George V TF and the presence of robust axial segments near the transform fault. They allow us to describe the complex evolution of the transform fault system. They also permit to locate new hydrothermal systems along the ridge axis. STORM cruise scientific party: F. Barrere, C. Boulart, G. Ceuleneer, N. Ferreira, B. Hanan, C. Hémond, S. Macleod, M. Maia, A. Maillard, S. Merkuryev, S.H. Park, S. Révillon, E. Ruellan, A. Schohn, S. Watson, and Y.S. Yang.

  4. Thickness of Knox Group overburden on Central Chestnut Ridge, Oak Ridge Reservation

    International Nuclear Information System (INIS)

    Staub, W.P.; Hopkins, R.A.

    1984-05-01

    The thickness of residual soil overlying the Knox Group along Central Chestnut Ridge was estimated by a conventional seismic refraction survey. The purpose of this survey was to identify sites on the Department of Energy's Oak Ridge Reservation where ample overburden exists above the water table for the shallow land burial of low-level radioactive waste. The results of the survey suggest that the upper slopes of the higher ridges in the area have a minimum of 16 to 26 m (52 to 85 ft) of overburden and that the crests of these ridges may have more than 30 m (100 ft). Therefore, it is unlikely that sound bedrock would be encountered during trench excavation [maximum of 10 m (32 ft)] along Central Chestnut Ridge. Also, the relatively low seismic wave velocities measured in the overburden suggest that the water table is generally deep. On the basis of these preliminary results, Central Chestnut Ridge appears to be suitable for further site characterization for the shallow land burial of low-level radioactive waste. 3 references, 5 figures, 1 table

  5. Radiogenic isotopes in enriched mid-ocean ridge basalts from Explorer Ridge, northeast Pacific Ocean

    Science.gov (United States)

    Cousens, Brian; Weis, Dominique; Constantin, Marc; Scott, Steve

    2017-09-01

    Extreme gradients in topography related to variations in magma supply are observed on the Southern Explorer Ridge (SER), part of the northern Juan de Fuca ridge system. We report radiogenic isotope (Pb, Sr, Nd, Hf) and geochemical data for twenty-four basalt whole-rock and glass samples collected from the length of the SER and from Explorer Deep, a rift to the north of the SER. Lavas from the SER form a north-south geochemical gradient, dominated by E-MORB at the northern axial high, and range from T-MORB to N-MORB towards the southern deepest part of the ridge. Linear relationships between incompatible element ratios and isotopic ratios in MORB along the ridge are consistent with mixing of magmas beneath the ridge to generate the geographic gradient from E- to N-MORB. The E-MORB have high Sr and Pb, and low Nd and Hf isotopic ratios, typical of enriched mantle that includes a FOZO or HIMU isotopic component. The West Valley and Endeavour segments of the northern Juan de Fuca ridge also include this isotopic component, but the proportion of the FOZO or HIMU component is more extreme in the SER basalts. The FOZO or HIMU component may be garnet-bearing peridotite, or a garnet pyroxenite embedded in peridotite. Recycled garnet pyroxenite better explains the very shallow SER axial high, high Nb/La and La/Sm, and the ;enriched; isotopic compositions.

  6. Absolute age determination of quaternary faults

    International Nuclear Information System (INIS)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik

    2000-03-01

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results

  7. Absolute age determination of quaternary faults

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2000-03-15

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results.

  8. Comparison of Cenozoic Faulting at the Savannah River Site to Fault Characteristics of the Atlantic Coast Fault Province: Implications for Fault Capability

    International Nuclear Information System (INIS)

    Cumbest, R.J.

    2000-01-01

    This study compares the faulting observed on the Savannah River Site and vicinity with the faults of the Atlantic Coastal Fault Province and concludes that both sets of faults exhibit the same general characteristics and are closely associated. Based on the strength of this association it is concluded that the faults observed on the Savannah River Site and vicinity are in fact part of the Atlantic Coastal Fault Province. Inclusion in this group means that the historical precedent established by decades of previous studies on the seismic hazard potential for the Atlantic Coastal Fault Province is relevant to faulting at the Savannah River Site. That is, since these faults are genetically related the conclusion of ''not capable'' reached in past evaluations applies.In addition, this study establishes a set of criteria by which individual faults may be evaluated in order to assess their inclusion in the Atlantic Coast Fault Province and the related association of the ''not capable'' conclusion

  9. Subaru FATS (fault tracking system)

    Science.gov (United States)

    Winegar, Tom W.; Noumaru, Junichi

    2000-07-01

    The Subaru Telescope requires a fault tracking system to record the problems and questions that staff experience during their work, and the solutions provided by technical experts to these problems and questions. The system records each fault and routes it to a pre-selected 'solution-provider' for each type of fault. The solution provider analyzes the fault and writes a solution that is routed back to the fault reporter and recorded in a 'knowledge-base' for future reference. The specifications of our fault tracking system were unique. (1) Dual language capacity -- Our staff speak both English and Japanese. Our contractors speak Japanese. (2) Heterogeneous computers -- Our computer workstations are a mixture of SPARCstations, Macintosh and Windows computers. (3) Integration with prime contractors -- Mitsubishi and Fujitsu are primary contractors in the construction of the telescope. In many cases, our 'experts' are our contractors. (4) Operator scheduling -- Our operators spend 50% of their work-month operating the telescope, the other 50% is spent working day shift at the base facility in Hilo, or day shift at the summit. We plan for 8 operators, with a frequent rotation. We need to keep all operators informed on the current status of all faults, no matter the operator's location.

  10. Why the 2002 Denali fault rupture propagated onto the Totschunda fault: implications for fault branching and seismic hazards

    Science.gov (United States)

    Schwartz, David P.; Haeussler, Peter J.; Seitz, Gordon G.; Dawson, Timothy E.

    2012-01-01

    The propagation of the rupture of the Mw7.9 Denali fault earthquake from the central Denali fault onto the Totschunda fault has provided a basis for dynamic models of fault branching in which the angle of the regional or local prestress relative to the orientation of the main fault and branch plays a principal role in determining which fault branch is taken. GeoEarthScope LiDAR and paleoseismic data allow us to map the structure of the Denali-Totschunda fault intersection and evaluate controls of fault branching from a geological perspective. LiDAR data reveal the Denali-Totschunda fault intersection is structurally simple with the two faults directly connected. At the branch point, 227.2 km east of the 2002 epicenter, the 2002 rupture diverges southeast to become the Totschunda fault. We use paleoseismic data to propose that differences in the accumulated strain on each fault segment, which express differences in the elapsed time since the most recent event, was one important control of the branching direction. We suggest that data on event history, slip rate, paleo offsets, fault geometry and structure, and connectivity, especially on high slip rate-short recurrence interval faults, can be used to assess the likelihood of branching and its direction. Analysis of the Denali-Totschunda fault intersection has implications for evaluating the potential for a rupture to propagate across other types of fault intersections and for characterizing sources of future large earthquakes.

  11. Architecture of thrust faults with alongstrike variations in fault-plane dip: anatomy of the Lusatian Fault, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Coubal, Miroslav; Adamovič, Jiří; Málek, Jiří; Prouza, V.

    2014-01-01

    Roč. 59, č. 3 (2014), s. 183-208 ISSN 1802-6222 Institutional support: RVO:67985831 ; RVO:67985891 Keywords : fault architecture * fault plane geometry * drag structures * thrust fault * sandstone * Lusatian Fault Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.405, year: 2014

  12. A deep hydrothermal fault zone in the lower oceanic crust, Samail ophiolite Oman

    Science.gov (United States)

    Zihlmann, B.; Mueller, S.; Koepke, J.; Teagle, D. A. H.

    2017-12-01

    Hydrothermal circulation is a key process for the exchange of chemical elements between the oceans and the solid Earth and for the extraction of heat from newly accreted crust at mid-ocean ridges. However, due to a dearth of samples from intact oceanic crust, or continuous samples from ophiolites, there remain major short comings in our understanding of hydrothermal circulation in the oceanic crust, especially in the deeper parts. In particular, it is unknown whether fluid recharge and discharge occurs pervasively or if it is mainly channeled within discrete zones such as faults. Here, we present a description of a hydrothermal fault zone that crops out in Wadi Gideah in the layered gabbro section of the Samail ophiolite of Oman. Field observations reveal a one meter thick chlorite-epidote normal fault with disseminated pyrite and chalcopyrite and heavily altered gabbro clasts at its core. In both, the hanging and the footwall the gabbro is altered and abundantly veined with amphibole, epidote, prehnite and zeolite. Whole rock mass balance calculations show enrichments in Fe, Mn, Sc, V, Co, Cu, Rb, Zr, Nb, Th and U and depletions of Si, Ca, Na, Cr, Zn, Sr, Ba and Pb concentrations in the fault rock compared to fresh layered gabbros. Gabbro clasts within the fault zone as well as altered rock from the hanging wall show enrichments in Na, Sc, V, Co, Rb, Zr, Nb and depletion of Cr, Ni, Cu, Zn, Sr and Pb. Strontium isotope whole rock data of the fault rock yield 87Sr/86Sr ratios of 0.7046, which is considerably more radiogenic than fresh layered gabbro from this locality (87Sr/86Sr = 0.7030 - 0.7034), and similar to black smoker hydrothermal signatures based on epidote, measured elsewhere in the ophiolite. Altered gabbro clasts within the fault zone show similar values with 87Sr/86Sr ratios of 0.7045 - 0.7050, whereas hanging wall and foot wall display values only slightly more radiogenic than fresh layered gabbro.The secondary mineral assemblages and strontium isotope

  13. Fault Features Extraction and Identification based Rolling Bearing Fault Diagnosis

    International Nuclear Information System (INIS)

    Qin, B; Sun, G D; Zhang L Y; Wang J G; HU, J

    2017-01-01

    For the fault classification model based on extreme learning machine (ELM), the diagnosis accuracy and stability of rolling bearing is greatly influenced by a critical parameter, which is the number of nodes in hidden layer of ELM. An adaptive adjustment strategy is proposed based on vibrational mode decomposition, permutation entropy, and nuclear kernel extreme learning machine to determine the tunable parameter. First, the vibration signals are measured and then decomposed into different fault feature models based on variation mode decomposition. Then, fault feature of each model is formed to a high dimensional feature vector set based on permutation entropy. Second, the ELM output function is expressed by the inner product of Gauss kernel function to adaptively determine the number of hidden layer nodes. Finally, the high dimension feature vector set is used as the input to establish the kernel ELM rolling bearing fault classification model, and the classification and identification of different fault states of rolling bearings are carried out. In comparison with the fault classification methods based on support vector machine and ELM, the experimental results show that the proposed method has higher classification accuracy and better generalization ability. (paper)

  14. Three-Dimensional Seismic Structure of the Mid-Atlantic Ridge: An Investigation of Tectonic, Magmatic, and Hydrothermal Processes in the Rainbow Area

    Science.gov (United States)

    Dunn, Robert A.; Arai, Ryuta; Eason, Deborah E.; Canales, J. Pablo; Sohn, Robert A.

    2017-12-01

    To test models of tectonic, magmatic, and hydrothermal processes along slow-spreading mid-ocean ridges, we analyzed seismic refraction data from the Mid-Atlantic Ridge INtegrated Experiments at Rainbow (MARINER) seismic and geophysical mapping experiment. Centered at the Rainbow area of the Mid-Atlantic Ridge (36°14'N), this study examines a section of ridge with volcanically active segments and a relatively amagmatic ridge offset that hosts the ultramafic Rainbow massif and its high-temperature hydrothermal vent field. Tomographic images of the crust and upper mantle show segment-scale variations in crustal structure, thickness, and the crust-mantle transition, which forms a vertical gradient rather than a sharp boundary. There is little definitive evidence for large regions of sustained high temperatures and melt in the lower crust or upper mantle along the ridge axes, suggesting that melts rising from the mantle intrude as small intermittent magma bodies at crustal and subcrustal levels. The images reveal large rotated crustal blocks, which extend to mantle depths in some places, corresponding to off-axis normal fault locations. Low velocities cap the Rainbow massif, suggesting an extensive near-surface alteration zone due to low-temperature fluid-rock reactions. Within the interior of the massif, seismic images suggest a mixture of peridotite and gabbroic intrusions, with little serpentinization. Here diffuse microearthquake activity indicates a brittle deformation regime supporting a broad network of cracks. Beneath the Rainbow hydrothermal vent field, fluid circulation is largely driven by the heat of small cooling melt bodies intruded into the base of the massif and channeled by the crack network and shallow faults.

  15. Serpentinization of mantle-derived peridotites at mid-ocean ridges: Mesh texture development in the context of tectonic exhumation

    Science.gov (United States)

    Rouméjon, Stéphane; Cannat, Mathilde

    2014-06-01

    At slow spreading ridges, axial detachment faults exhume mantle-derived peridotites and hydrothermal alteration causes serpentinization in a domain extending more than 1 km next to the fault. At the microscopic scale, serpentinization progresses from a microfracture network toward the center of olivine relicts and forms a mesh texture. We present a petrographic study (SEM, EBSD, and Raman) of the serpentine mesh texture in a set of 278 abyssal serpentinized peridotites from the Mid-Atlantic and Southwest Indian Ridges. We show that serpentinization initiated along two intersecting sets of microfractures that have consistent orientations at the sample scale, and in at least one studied location, at the 100 m scale. We propose that these microfractures formed in fresh peridotites due to combined thermal and tectonic stresses and subsequently served as channels for serpentinizing fluids. Additional reaction-induced cracks developed for serpentinization extents <20%. The resulting microfracture network has a typical spacing of ˜60 µm but most serpentinization occurs next to a subset of these microfractures that define mesh cells 100-400 µm in size. Apparent mesh rim thickness is on average 33 ± 19 µm corresponding to serpentinization extents of 70-80%. Published laboratory experiments suggest that mesh rims formation could be completed in a few years (i.e., quasi instantaneous at the plate tectonic timescale). The depth and extent of the serpentinization domain in the detachment fault's footwall are probably variable in time and space and as a result we expect that the serpentine mesh texture at slow spreading ridges forms at variable rates with a spatially heterogeneous distribution.

  16. 20 CFR 410.561b - Fault.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Fault. 410.561b Section 410.561b Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, TITLE IV-BLACK LUNG BENEFITS (1969- ) Payment of Benefits § 410.561b Fault. Fault as used in without fault (see § 410...

  17. Fault Detection for Diesel Engine Actuator

    DEFF Research Database (Denmark)

    Blanke, M.; Bøgh, S.A.; Jørgensen, R.B.

    1994-01-01

    Feedback control systems are vulnerable to faults in control loop sensors and actuators, because feedback actions may cause abrupt responses and process damage when faults occur.......Feedback control systems are vulnerable to faults in control loop sensors and actuators, because feedback actions may cause abrupt responses and process damage when faults occur....

  18. 22 CFR 17.3 - Fault.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fault. 17.3 Section 17.3 Foreign Relations...) § 17.3 Fault. A recipient of an overpayment is without fault if he or she performed no act of... agency may have been at fault in initiating an overpayment will not necessarily relieve the individual...

  19. Active fault diagnosis by temporary destabilization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

    An active fault diagnosis method for parametric or multiplicative faults is proposed. The method periodically adds a term to the controller that for a short period of time renders the system unstable if a fault has occurred, which facilitates rapid fault detection. An illustrative example is given....

  20. From fault classification to fault tolerance for multi-agent systems

    CERN Document Server

    Potiron, Katia; Taillibert, Patrick

    2013-01-01

    Faults are a concern for Multi-Agent Systems (MAS) designers, especially if the MAS are built for industrial or military use because there must be some guarantee of dependability. Some fault classification exists for classical systems, and is used to define faults. When dependability is at stake, such fault classification may be used from the beginning of the system's conception to define fault classes and specify which types of faults are expected. Thus, one may want to use fault classification for MAS; however, From Fault Classification to Fault Tolerance for Multi-Agent Systems argues that

  1. Model selection in kernel ridge regression

    DEFF Research Database (Denmark)

    Exterkate, Peter

    2013-01-01

    Kernel ridge regression is a technique to perform ridge regression with a potentially infinite number of nonlinear transformations of the independent variables as regressors. This method is gaining popularity as a data-rich nonlinear forecasting tool, which is applicable in many different contexts....... The influence of the choice of kernel and the setting of tuning parameters on forecast accuracy is investigated. Several popular kernels are reviewed, including polynomial kernels, the Gaussian kernel, and the Sinc kernel. The latter two kernels are interpreted in terms of their smoothing properties......, and the tuning parameters associated to all these kernels are related to smoothness measures of the prediction function and to the signal-to-noise ratio. Based on these interpretations, guidelines are provided for selecting the tuning parameters from small grids using cross-validation. A Monte Carlo study...

  2. Differential Fault Analysis on CLEFIA

    Science.gov (United States)

    Chen, Hua; Wu, Wenling; Feng, Dengguo

    CLEFIA is a new 128-bit block cipher proposed by SONY corporation recently. The fundamental structure of CLEFIA is a generalized Feistel structure consisting of 4 data lines. In this paper, the strength of CLEFIA against the differential fault attack is explored. Our attack adopts the byte-oriented model of random faults. Through inducing randomly one byte fault in one round, four bytes of faults can be simultaneously obtained in the next round, which can efficiently reduce the total induce times in the attack. After attacking the last several rounds' encryptions, the original secret key can be recovered based on some analysis of the key schedule. The data complexity analysis and experiments show that only about 18 faulty ciphertexts are needed to recover the entire 128-bit secret key and about 54 faulty ciphertexts for 192/256-bit keys.

  3. Fault Tolerant External Memory Algorithms

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund; Brodal, Gerth Stølting; Mølhave, Thomas

    2009-01-01

    Algorithms dealing with massive data sets are usually designed for I/O-efficiency, often captured by the I/O model by Aggarwal and Vitter. Another aspect of dealing with massive data is how to deal with memory faults, e.g. captured by the adversary based faulty memory RAM by Finocchi and Italiano....... However, current fault tolerant algorithms do not scale beyond the internal memory. In this paper we investigate for the first time the connection between I/O-efficiency in the I/O model and fault tolerance in the faulty memory RAM, and we assume that both memory and disk are unreliable. We show a lower...... bound on the number of I/Os required for any deterministic dictionary that is resilient to memory faults. We design a static and a dynamic deterministic dictionary with optimal query performance as well as an optimal sorting algorithm and an optimal priority queue. Finally, we consider scenarios where...

  4. Cell boundary fault detection system

    Science.gov (United States)

    Archer, Charles Jens [Rochester, MN; Pinnow, Kurt Walter [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian Edward [Rochester, MN

    2009-05-05

    A method determines a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  5. Oak Ridge National Laboratory Waste Management Plan

    International Nuclear Information System (INIS)

    1992-12-01

    The objective of the Oak Ridge National Laboratory Waste Management Plan is to compile and to consolidate information annually on how the ORNL Waste Management Program is conducted, which waste management facilities are being used to manage wastes, what forces are acting to change current waste management systems, what activities are planned for the forthcoming fiscal year (FY), and how all of the activities are documented

  6. ORNL (Oak Ridge National Laboratory) 89

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, T.D.; Appleton, B.R.; Jefferson, J.W.; Merriman, J.R.; Mynatt, F.R.; Richmond, C.R.; Rosenthal, M.W.

    1989-01-01

    This is the inaugural issues of an annual publication about the Oak Ridge National Laboratory. Here you will find a brief overview of ORNL, a sampling of our recent research achievements, and a glimpse of the directions we want to take over the next 15 years. A major purpose of ornl 89 is to provide the staff with a sketch of the character and dynamics of the Laboratory.

  7. ORNL [Oak Ridge National Laboratory] 89

    International Nuclear Information System (INIS)

    Anderson, T.D.; Appleton, B.R.; Jefferson, J.W.; Merriman, J.R.; Mynatt, F.R.; Richmond, C.R.; Rosenthal, M.W.

    1989-01-01

    This is the inaugural issues of an annual publication about the Oak Ridge National Laboratory. Here you will find a brief overview of ORNL, a sampling of our recent research achievements, and a glimpse of the directions we want to take over the next 15 years. A major purpose of ornl 89 is to provide the staff with a sketch of the character and dynamics of the Laboratory

  8. Oak Ridge National Laboratory Waste Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-01

    The objective of the Oak Ridge National Laboratory Waste Management Plan is to compile and to consolidate information annually on how the ORNL Waste Management Program is conducted, which waste management facilities are being used to manage wastes, what forces are acting to change current waste management systems, what activities are planned for the forthcoming fiscal year (FY), and how all of the activities are documented.

  9. Testing Pixel Translation Digital Elevation Models to Reconstruct Slip Histories: An Example from the Agua Blanca Fault, Baja California, Mexico

    Science.gov (United States)

    Wilson, J.; Wetmore, P. H.; Malservisi, R.; Ferwerda, B. P.; Teran, O.

    2012-12-01

    We use recently collected slip vector and total offset data from the Agua Blanca fault (ABF) to constrain a pixel translation digital elevation model (DEM) to reconstruct the slip history of this fault. This model was constructed using a Perl script that reads a DEM file (Easting, Northing, Elevation) and a configuration file with coordinates that define the boundary of each fault segment. A pixel translation vector is defined as a magnitude of lateral offset in an azimuthal direction. The program translates pixels north of the fault and prints their pre-faulting position to a new DEM file that can be gridded and displayed. This analysis, where multiple DEMs are created with different translation vectors, allows us to identify areas of transtension or transpression while seeing the topographic expression in these areas. The benefit of this technique, in contrast to a simple block model, is that the DEM gives us a valuable graphic which can be used to pose new research questions. We have found that many topographic features correlate across the fault, i.e. valleys and ridges, which likely have implications for the age of the ABF, long term landscape evolution rates, and potentially provide conformation for total slip assessments The ABF of northern Baja California, Mexico is an active, dextral strike slip fault that transfers Pacific-North American plate boundary strain out of the Gulf of California and around the "Big Bend" of the San Andreas Fault. Total displacement on the ABF in the central and eastern parts of the fault is 10 +/- 2 km based on offset Early-Cretaceous features such as terrane boundaries and intrusive bodies (plutons and dike swarms). Where the fault bifurcates to the west, the northern strand (northern Agua Blanca fault or NABF) is constrained to 7 +/- 1 km. We have not yet identified piercing points on the southern strand, the Santo Tomas fault (STF), but displacement is inferred to be ~4 km assuming that the sum of slip on the NABF and STF is

  10. Deformation around basin scale normal faults

    International Nuclear Information System (INIS)

    Spahic, D.

    2010-01-01

    Faults in the earth crust occur within large range of scales from microscale over mesoscopic to large basin scale faults. Frequently deformation associated with faulting is not only limited to the fault plane alone, but rather forms a combination with continuous near field deformation in the wall rock, a phenomenon that is generally called fault drag. The correct interpretation and recognition of fault drag is fundamental for the reconstruction of the fault history and determination of fault kinematics, as well as prediction in areas of limited exposure or beyond comprehensive seismic resolution. Based on fault analyses derived from 3D visualization of natural examples of fault drag, the importance of fault geometry for the deformation of marker horizons around faults is investigated. The complex 3D structural models presented here are based on a combination of geophysical datasets and geological fieldwork. On an outcrop scale example of fault drag in the hanging wall of a normal fault, located at St. Margarethen, Burgenland, Austria, data from Ground Penetrating Radar (GPR) measurements, detailed mapping and terrestrial laser scanning were used to construct a high-resolution structural model of the fault plane, the deformed marker horizons and associated secondary faults. In order to obtain geometrical information about the largely unexposed master fault surface, a standard listric balancing dip domain technique was employed. The results indicate that for this normal fault a listric shape can be excluded, as the constructed fault has a geologically meaningless shape cutting upsection into the sedimentary strata. This kinematic modeling result is additionally supported by the observation of deformed horizons in the footwall of the structure. Alternatively, a planar fault model with reverse drag of markers in the hanging wall and footwall is proposed. Deformation around basin scale normal faults. A second part of this thesis investigates a large scale normal fault

  11. Global survey of lunar wrinkle ridge formation times

    Science.gov (United States)

    Yue, Z.; Michael, G. G.; Di, K.; Liu, J.

    2017-11-01

    Wrinkle ridges are a common feature of the lunar maria and record subsequent contraction of mare infill. Constraining the timing of wrinkle ridge formation from crater counts is challenging because they have limited areal extent and it is difficult to determine whether superposed craters post-date ridge formation or have alternatively been uplifted by the deformation. Some wrinkle ridges do allow determination to be made. This is possible where a ridge shows a sufficiently steep boundary or scarp that can be identified as deforming an intersecting crater or the crater obliterates the relief of the ridge. Such boundaries constitute only a small fraction of lunar wrinkle ridge structures yet they are sufficiently numerous to enable us to obtain statistically significant crater counts over systems of structurally related wrinkle ridges. We carried out a global mapping of mare wrinkle ridges, identifying appropriate boundaries for crater identification, and mapping superposed craters. Selected groups of ridges were analyzed using the buffered crater counting method. We found that, except for the ridges in mare Tranquilitatis, the ridge groups formed with average ages between 3.5 and 3.1 Ga ago, or 100-650 Ma after the oldest observable erupted basalts where they are located. We interpret these results to suggest that local stresses from loading by basalt fill are the principal agent responsible for the formation of lunar wrinkle ridges, as others have proposed. We find a markedly longer interval before wrinkle ridge formation in Tranquilitatis which likely indicates a different mechanism of stress accumulation at this site.

  12. Qademah Fault Passive Data

    KAUST Repository

    Hanafy, Sherif M.

    2014-01-01

    OBJECTIVE: In this field trip we collect passive data to 1. Convert passive to surface waves 2. Locate Qademah fault using surface wave migration INTRODUCTION: In this field trip we collected passive data for several days. This data will be used to find the surface waves using interferometry and then compared to active-source seismic data collected at the same location. A total of 288 receivers are used. A 3D layout with 5 m inline intervals and 10 m cross line intervals is used, where we used 12 lines with 24 receivers at each line. You will need to download the file (rec_times.mat), it contains important information about 1. Field record no 2. Record day 3. Record month 4. Record hour 5. Record minute 6. Record second 7. Record length P.S. 1. All files are converted from original format (SEG-2) to matlab format P.S. 2. Overlaps between records (10 to 1.5 sec.) are already removed from these files

  13. Exposing the faults

    International Nuclear Information System (INIS)

    Richardson, P.J.

    1989-01-01

    UK NIREX, the body with responsibility for finding an acceptable strategy for deposition of radioactive waste has given the impression throughout its recent public consultation that the problem of nuclear waste is one of public and political acceptability, rather than one of a technical nature. However the results of the consultation process show that it has no mandate from the British public to develop a single, national, deep repository for the burial of radioactive waste. There is considerable opposition to this method of managing radioactive waste and suspicion of the claims by NIREX concerning the supposed integrity and safety of this deep burial option. This report gives substance to those suspicions and details the significant areas of uncertainty in the concept of effective geological containment of hazardous radioactive elements, which remain dangerous for tens of thousands of years. Because the science of geology is essentially retrospective rather than predictive, NIREX's plans for a single, national, deep 'repository' depend heavily upon a wide range of assumptions about the geological and hydrogeological regimes in certain areas of the UK. This report demonstrates that these assumptions are based on a limited understanding of UK geology and on unvalidated and simplistic theoretical models of geological processes, the performance of which can never be directly tested over the long time-scales involved. NIREX's proposals offer no guarantees for the safe and effective containment of radioactivity. They are deeply flawed. This report exposes the faults. (author)

  14. Fault-tolerant rotary actuator

    Science.gov (United States)

    Tesar, Delbert

    2006-10-17

    A fault-tolerant actuator module, in a single containment shell, containing two actuator subsystems that are either asymmetrically or symmetrically laid out is provided. Fault tolerance in the actuators of the present invention is achieved by the employment of dual sets of equal resources. Dual resources are integrated into single modules, with each having the external appearance and functionality of a single set of resources.

  15. Static Decoupling in fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    1998-01-01

    An algebraic approach is given for a design of a static residual weighting factor in connection with fault detection. A complete parameterization is given of the weighting factor which will minimize a given performance index......An algebraic approach is given for a design of a static residual weighting factor in connection with fault detection. A complete parameterization is given of the weighting factor which will minimize a given performance index...

  16. Diagnosis and fault-tolerant control

    CERN Document Server

    Blanke, Mogens; Lunze, Jan; Staroswiecki, Marcel

    2016-01-01

    Fault-tolerant control aims at a gradual shutdown response in automated systems when faults occur. It satisfies the industrial demand for enhanced availability and safety, in contrast to traditional reactions to faults, which bring about sudden shutdowns and loss of availability. The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process that can be used to ensure fault tolerance. It also introduces design methods suitable for diagnostic systems and fault-tolerant controllers for continuous processes that are described by analytical models of discrete-event systems represented by automata. The book is suitable for engineering students, engineers in industry and researchers who wish to get an overview of the variety of approaches to process diagnosis and fault-tolerant contro...

  17. Alveolar ridge keratosis - a retrospective clinicopathological study

    Science.gov (United States)

    2013-01-01

    Background Alveolar ridge keratosis (ARK) is a distinct, benign clinicopathological entity, characterized by a hyperkeratotic plaque or patch that occurs on the alveolar edentulous ridge or on the retromolar trigone, considered to be caused by chronic frictional trauma. The aim of this retrospective study is to present the clinicopathological features of 23 consecutive cases of ARK. Material and methods The 23 biopsy samples of ARK were selected and pathological features were revised (keratosis, acanthosis, surface architecture, and inflammation). Factors such as the patient’s gender, age, anatomical location, tobacco and alcohol use were analyzed. Results Sixteen out of the 23 cases studied were men and 7 women with a mean age of 55.05 (age ranged from 17 to 88 years). Thirteen cases had a history of tobacco habit, amongst whom, 4 also presented alcohol consumption. All the cases presented only unilateral lesions. Nineteen cases involved the retromolar trigone while 4 cases involved edentulous alveolar ridges. When observed microscopically, the lesions were mainly characterized by moderate to important hyperorthokeratosis. Inflammation was scanty or absent. In four of the cases, the presence of melanin pigment in the superficial corium or in the cytoplasm of macrophages was detected. None of the cases showed any features of dysplasia. Conclusion Our results reveal that ARK is a benign lesion. However, the high prevalence of smokers amongst the patients might suggest that some potentially malignant disorders such as tobacco associated leukoplakia may clinically mimic ARK. PMID:23587097

  18. 3D seismic expression of fluid migration and mud remobilization on the Gjallar Ridge, offshore mid-Norway

    DEFF Research Database (Denmark)

    Hansen, J.P.V.; Cartwright, J.A.; Huuse, M.

    2005-01-01

    This paper presents a three-dimensional (3D) seismic analysis of sediment remobilization and fluid migration in a 2000-km2 area above the Gjallar Ridge located in the Vøring Basin, offshore Norway. Three distinct types of mounded structures have been identified as resulting from focused fluid......-seated normal faults. Type B structures comprise relatively steep-sided mounds and are restricted to the pre-Miocene interval. They are often located above narrow zones of discontinuous low-amplitude reflections resembling gas chimneys. Some of the Type B structures are associated with stacked amplitude...

  19. Continentward-dipping detachment fault system and asymmetric rift structure of the Baiyun Sag, northern South China Sea

    Science.gov (United States)

    Zhou, Zhichao; Mei, Lianfu; Liu, Jun; Zheng, Jinyun; Chen, Liang; Hao, Shihao

    2018-02-01

    The rift architecture and deep crustal structure of the distal margin at the mid-northern margin of the South China Sea have been previously investigated by using deep seismic reflection profiles. However, one fundamental recurring problem in the debate is the extensional fault system and rift structure of the hyperextended rift basins (Baiyun Sag and Liwan Sag) within the distal margin because of the limited amount of seismic data. Based on new 3D seismic survey data and 2D seismic reflection profiles, we observe an array of fault blocks in the Baiyun Sag, which were tilted towards the ocean by extensional faulting. The extensional faults consistently dip towards the continent. Beneath the tilted fault blocks and extensional faults, a low-angle, high-amplitude and continuous reflection has been interpreted as the master detachment surface that controls the extension process. During rifting, the continentward-dipping normal faults evolved in a sequence from south to north, generating the asymmetric rift structure of the Baiyun Sag. The Baiyun Sag is separated from the oceanic domain by a series of structural highs that were uplifted by magmatic activity in response to the continental breakup at 33 Ma and a ridge jump to the south at 26-24 Ma. Therefore, we propose that magmatism played a significant role in the continental extension and final breakup in the South China Sea.

  20. Aeromagnetic anomalies over faulted strata

    Science.gov (United States)

    Grauch, V.J.S.; Hudson, Mark R.

    2011-01-01

    High-resolution aeromagnetic surveys are now an industry standard and they commonly detect anomalies that are attributed to faults within sedimentary basins. However, detailed studies identifying geologic sources of magnetic anomalies in sedimentary environments are rare in the literature. Opportunities to study these sources have come from well-exposed sedimentary basins of the Rio Grande rift in New Mexico and Colorado. High-resolution aeromagnetic data from these areas reveal numerous, curvilinear, low-amplitude (2–15 nT at 100-m terrain clearance) anomalies that consistently correspond to intrasedimentary normal faults (Figure 1). Detailed geophysical and rock-property studies provide evidence for the magnetic sources at several exposures of these faults in the central Rio Grande rift (summarized in Grauch and Hudson, 2007, and Hudson et al., 2008). A key result is that the aeromagnetic anomalies arise from the juxtaposition of magnetically differing strata at the faults as opposed to chemical processes acting at the fault zone. The studies also provide (1) guidelines for understanding and estimating the geophysical parameters controlling aeromagnetic anomalies at faulted strata (Grauch and Hudson), and (2) observations on key geologic factors that are favorable for developing similar sedimentary sources of aeromagnetic anomalies elsewhere (Hudson et al.).