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Sample records for taylor dome ice

  1. Beryllium-10 in the Taylor Dome ice core: Applications to Antarctic glaciology and paleoclimatology

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    Steig, E.J.

    1996-12-31

    An ice core was drilled at Taylor dome, East Antarctica, reaching to bedrock at 554 meters. Oxygen-isotope measurements reveal climatic fluctuations through the last interglacial period. To facilitate comparison of the Taylor Dome paleoclimate record with geologic data and results from other deep ice cores, several glaciological issues need to be addressed. In particular, accumulation data are necessary as input for numerical ice-flow-models, for determining the flux of chemical constituents from measured concentrations, and for calculation of the offset in age between ice and trapped air in the core. The analysis of cosmogenic beryllium-10 provides a geochemical method for constraining the accumulation-rate history at Taylor Dome. High-resolution measurements were made in shallow firn cores and snow pits to determine the relationship among beryllium-10 concentrations, wet and dry deposition mechanisms, and snow-accumulation rates. Comparison between theoretical and measured variations in deposition over the last 75 years constrains the relationship between beryllium-10 deposition and global average production rates. The results indicate that variations in geomagnetically-modulated production-rate do not strongly influence beryllium-10 deposition at Taylor Dome. Although solar modulation of production rate is important for time scales of years to centuries, snow-accumulation rate is the dominant control on ice-core beryllium-10 concentrations for longer periods. Results show that the Taylor Dome core can be used to provide new constraints on regional climate over the last 130,000 years, complementing the terrestrial and marine geological record from the Dry Valley, Transantarctic Mountains and western Ross Sea.

  2. The Second Deep Ice Coring Project at Dome Fuji, Antarctica

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    Hideaki Motoyama

    2007-09-01

    Full Text Available Throughout the history of the polar icecaps, dust and aerosols have been transported through the atmosphere to the poles, to be preserved within the annually freezing ice of the growing ice shields. Therefore, the Antarctic ice sheet is a “time capsule" for environmental data, containing information of ancient periods of Earth’s history. To unravel this history and decode cycles in glaciations and global change is among the major goals of the Dome Fuji Ice Coring Project.

  3. Ice crystal precipitation at Dome C site (East Antarctica)

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    Santachiara, G.; Belosi, F.; Prodi, F.

    2016-01-01

    For the first time, falling ice crystals were collected on glass slides covered with a thin layer of 2% formvar in chloroform at the Dome Concordia site (Dome C), Antarctica. Samplings were performed in the framework of the 27th Italian Antarctica expedition of the Italian National Program for Research in Antarctica in the period 21 February-6 August 2012. Events of clear-sky precipitations and precipitations from clouds were considered and the replicas obtained were examined under Scanning Electron Microscope (SEM). Several shapes of ice crystals were identified, including ;diamond dust; (plates, pyramids, hollow and solid columns), and crystal aggregates varying in complexity. Single events often contained both small (10 μm to 50 μm) and large (hundreds of microns) crystals, suggesting that crystals can form simultaneously near the ground (height of a few hundred metres) and at higher layers (height of thousands of metres). Images of sampled crystal replicas showed that single bullets are not produced separately, but by the disintegration of combinations of bullets. Rimed ice crystals were absent in the Dome C samples, i.e. the only mode of crystal growth was water vapour diffusion. On considering the aerosol in the sampled crystals, we reached the conclusion that inertial impaction, interception and Brownian motion were insufficient to explain the scavenged aerosol. We therefore presume that phoretic forces play a role in scavenging during the crystal growth process.

  4. Deep ice coring at Dome Fuji Station, Antarctica

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    Yoshiyuki Fujii

    1999-03-01

    Full Text Available Deep ice coring was carried out at Dome Fuji Station, Antarctica in 1995 and 1996 following a pilot borehole drilled and cased with FRP pipes in 1993,and reached 2503.52m in December 1996. Total numbers of ice coring runs below the pilot borehole and chip collection were 1369 and 837 respectively. The mean coring depths per run and per day were 1.75m and 8.21m respectively. We report the outline of the coring operation, the system, coring method, and troubles encountered during the coring work.

  5. Barnes Ice Cap South Dome Trilateration Net Survey Data 1970-1984, Version 1

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    National Aeronautics and Space Administration — The Barnes Ice Cap data set contains survey measurements of a network of 43 stakes along a 10 km flow line on the northeast flank of the south dome of the Barnes Ice...

  6. Unstable Titan-generated Rayleigh-Taylor Lakes Impact Ice

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    Umurhan, O. M.; Korycansky, D. G.; Zahnle, K. J.

    2014-12-01

    The evolution of surface morphology on Titan, Triton, and other worlds is strongly influenced by the interplay of various fluid dynamical processes. Specifically, overturning instabilities can easily arise due to the special circumstances of landform evolution that probably occurred on these worlds. On Titan, large impacts that formed basins like Menrva crater (and possibly Hotei Regio) would have generated impact-melt ice lakes unstably arranged over less dense ice. Cantaloupe terrains, for example as seen on Triton, may be the result of condensation of volatiles (methane, nitrogen) leading to unstably stratified layers of different compositions and densities. In each of these cases, Rayleigh-Taylor instabilities leading to large scale diapirism may be at play. In addition to the dynamics of these instabilities, other physical effects (e.g. heat diffusion, freezing/melting, porosity, temperature dependent viscosity) likely play an important role in the evolution of these features. In this ongoing study, we examine the properties of unstably stratified fluids in which the lower less-dense ice has a temperature dependent viscosity. Surprisingly, we find that there exists an optimal disturbance length scale corresponding to the fastest growth of the Rayleigh-Taylor instability. For unstably stratified layers of water (low viscosity heavy liquid lying above an ice whose viscosity increases with depth) the fastest growing mode corresponds to 40-60 km scales with overturn times of approximately 100 days. We present a detailed numerical stability analysis in a corresponding Boussinessq model (in the creeping flow limit) incorporating thermal conduction and latent heat release and we examine the stability properties surveying a variety of parameters. We have also developed a two-dimensional numerical code (a hybrid spectral/compact-differencing scheme) to model the evolution of such systems for which we shall present preliminary numerical results depicting the outcome of

  7. Is there 1.5-million-year-old ice near Dome C, Antarctica?

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    F. Parrenin

    2017-11-01

    Full Text Available Ice sheets provide exceptional archives of past changes in polar climate, regional environment and global atmospheric composition. The oldest dated deep ice core drilled in Antarctica has been retrieved at EPICA Dome C (EDC, reaching ∼ 800 000 years. Obtaining an older paleoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we use internal isochrones, identified from airborne radar coupled to ice-flow modelling to estimate the age of basal ice along transects in the Dome C area. Three glaciological properties are inferred from isochrones: surface accumulation rate, geothermal flux and the exponent of the Lliboutry velocity profile. We find that old ice (> 1.5 Myr, 1.5 million years likely exists in two regions: one ∼ 40 km south-west of Dome C along the ice divide to Vostok, close to a secondary dome that we name Little Dome C (LDC, and a second region named North Patch (NP located 10–30 km north-east of Dome C, in a region where the geothermal flux is apparently relatively low. Our work demonstrates the value of combining radar observations with ice flow modelling to accurately represent the true nature of ice flow, and understand the formation of ice-sheet architecture, in the centre of large ice sheets.

  8. Siple Dome ice reveals two modes of millennial CO2 change during the last ice age

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    Ahn, Jinho; Brook, Edward J.

    2014-01-01

    Reconstruction of atmospheric CO2 during times of past abrupt climate change may help us better understand climate-carbon cycle feedbacks. Previous ice core studies reveal simultaneous increases in atmospheric CO2 and Antarctic temperature during times when Greenland and the northern hemisphere experienced very long, cold stadial conditions during the last ice age. Whether this relationship extends to all of the numerous stadial events in the Greenland ice core record has not been clear. Here we present a high-resolution record of atmospheric CO2 from the Siple Dome ice core, Antarctica for part of the last ice age. We find that CO2 does not significantly change during the short Greenlandic stadial events, implying that the climate system perturbation that produced the short stadials was not strong enough to substantially alter the carbon cycle. PMID:24781344

  9. Digital Imaging for Siple Dome Ice Core Analysis, Antarctica, Version 1

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    National Aeronautics and Space Administration — This data set contains high-resolution digital images of thin and thick sections cut from the 1003 meter Siple Dome A main ice core. The images are useful for...

  10. Barnes Ice Cap South Dome Trilateration Net Survey Data 1970-1984

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Barnes Ice Cap data set contains survey measurements of a network of 43 stakes along a 10 km flow line on the northeast flank of the south dome of the Barnes Ice...

  11. Location of a new ice core site at Talos Dome (East Antarctica

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    I. Tabacco

    2006-06-01

    Full Text Available In the frame of glaciology and palaeoclimate research, Talos Dome (72°48lS; 159°06lE, an ice dome on the East Antarctic plateau, represents the new selected site for a new deep ice core drilling. The increasing interest in this region is due to the fact that the ice accumulation is higher here than in other domes in East Antarctica. A new deep drilling in this site could give important information about the climate changes near the coast. Previous papers showed that the dome summit is situated above a sloped bedrock. A new position on a relatively flat bedrock 5-6 km far from here in the SE direction was defined as a possible new ice core site for an European (Italy, France, Swiss and United Kingdom drilling project named as TALDICE (TALos Dome Ice Core Project. This point, named as ID1 (159°11l00mE; 72°49l40mS, became the centre of the Radio Echo Sounding (RES flight plan during the 2003 Italian Antarctic expedition, with the aim of confirming the new drilling site choice. In this paper 2001 and 2003 RES data sets have been used to draw a better resolution of ice thickness, bottom morphology and internal layering of a restricted area around the dome. Based on the final results, point ID1 has been confirmed as the new coring site. Finally, the preliminary operations about the installation of the summer ice core camp (TALDICE at ID1 site carried out during the XX Italian Antarctic expedition (November 2004-December 2005 are briefly described.

  12. Radio Echo Sounding (RES investigations at Talos Dome (East Antarctica: bedrock topography and ice thickness

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    I. E. Tabacco

    2003-06-01

    Full Text Available Radio echo sounding measurements were collected during two Antarctic expeditions to determine the ice thickness and the sub-glacial morphology of Talos Dome in the region around 72°48'S; 159°06'E (about 6400 km2 on the edge of the East Antarctic plateau adjacent to Victoria Land in the western Ross Sea sector. The increasing interest in this region is due to the fact that in this area the ice accumulation is higher than in other sites in East Antarctica. Because of this, Talos Dome could be a new site for a project of a deep ice core drilling to obtain information on climate changes near the coast of Antarctica. In this frame, the knowledge of the bedrock topography is of great importance to choose the best location for the drilling site. In this paper, airborne radio echo sounding results from two Antarctic expeditions (1997 and 1999 are presented. Bedrock topography in bi- and three-dimensions for the Talos Dome region are discussed.

  13. Modeling the Thickness of Perennial Ice Covers on Stratified Lakes of the Taylor Valley, Antarctica

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    Obryk, M. K.; Doran, P. T.; Hicks, J. A.; McKay, C. P.; Priscu, J. C.

    2016-01-01

    A one-dimensional ice cover model was developed to predict and constrain drivers of long term ice thickness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface radiative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 years (between 1996 and 2012) of ice thickness changes for west lobe of Lake Bonney (average ice thickness = 3.53 m; RMSE = 0.09 m, n = 118) and Lake Fryxell (average ice thickness = 4.22 m; RMSE = 0.21 m, n = 128). Long-term ice thickness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of lakes exceeding a liquid water column depth of 20 m can either impede or facilitate ice thickness change depending on the predominant climatic trend (temperature cooling or warming). As such, shallow (< 20 m deep water columns) perennially ice-covered lakes without deep temperature maxima are more sensitive indicators of climate change. The long-term ice thickness trends are a result of surface energy flux and heat flux from the deep temperature maximum in the water column, the latter of which results from absorbed solar radiation.

  14. Where is the 1-million-year-old ice at Dome A?

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    L. Zhao

    2018-05-01

    Full Text Available Ice fabric influences the rheology of ice, and hence the age–depth profile at ice core drilling sites. To investigate the age–depth profile to be expected of the ongoing deep ice coring at Kunlun station, Dome A, we use the depth-varying anisotropic fabric suggested by the recent polarimetric measurements around Dome A along with prescribed fabrics ranging from isotropic through girdle to single maximum in a three-dimensional, thermo-mechanically coupled full-Stokes model of a 70  ×  70 km2 domain around Kunlun station. This model allows for the simulation of the near basal ice temperature and age, and ice flow around the location of the Chinese deep ice coring site. Ice fabrics and geothermal heat flux strongly affect the vertical advection and basal temperature which consequently control the age profile. Constraining modeled age–depth profiles with dated radar isochrones to 2∕3 ice depth, the surface vertical velocity, and also the spatial variability of a radar isochrones dated to 153.3 ka BP, limits the age of the deep ice at Kunlun to between 649 and 831 ka, a much smaller range than previously inferred. The simple interpretation of the polarimetric radar fabric data that we use produces best fits with a geothermal heat flux of 55 mW m−2. A heat flux of 50 mW m−2 is too low to fit the deeper radar layers, and 60 mW m−2 leads to unrealistic surface velocities. The modeled basal temperature at Kunlun reaches the pressure melting point with a basal melting rate of 2.2–2.7 mm a−1. Using the spatial distribution of basal temperatures and the best fit fabric suggests that within 400 m of Kunlun station, 1-million-year-old ice may be found 200 m above the bed, and that there are large regions where even older ice is well above the bedrock within 5–6 km of the Kunlun station.

  15. Where is the 1-million-year-old ice at Dome A?

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    Zhao, Liyun; Moore, John C.; Sun, Bo; Tang, Xueyuan; Guo, Xiaoran

    2018-05-01

    Ice fabric influences the rheology of ice, and hence the age-depth profile at ice core drilling sites. To investigate the age-depth profile to be expected of the ongoing deep ice coring at Kunlun station, Dome A, we use the depth-varying anisotropic fabric suggested by the recent polarimetric measurements around Dome A along with prescribed fabrics ranging from isotropic through girdle to single maximum in a three-dimensional, thermo-mechanically coupled full-Stokes model of a 70 × 70 km2 domain around Kunlun station. This model allows for the simulation of the near basal ice temperature and age, and ice flow around the location of the Chinese deep ice coring site. Ice fabrics and geothermal heat flux strongly affect the vertical advection and basal temperature which consequently control the age profile. Constraining modeled age-depth profiles with dated radar isochrones to 2/3 ice depth, the surface vertical velocity, and also the spatial variability of a radar isochrones dated to 153.3 ka BP, limits the age of the deep ice at Kunlun to between 649 and 831 ka, a much smaller range than previously inferred. The simple interpretation of the polarimetric radar fabric data that we use produces best fits with a geothermal heat flux of 55 mW m-2. A heat flux of 50 mW m-2 is too low to fit the deeper radar layers, and 60 mW m-2 leads to unrealistic surface velocities. The modeled basal temperature at Kunlun reaches the pressure melting point with a basal melting rate of 2.2-2.7 mm a-1. Using the spatial distribution of basal temperatures and the best fit fabric suggests that within 400 m of Kunlun station, 1-million-year-old ice may be found 200 m above the bed, and that there are large regions where even older ice is well above the bedrock within 5-6 km of the Kunlun station.

  16. High-resolution boundary conditions of an old ice target near Dome C, Antarctica

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    Young, Duncan A.; Roberts, Jason L.; Ritz, Catherine; Frezzotti, Massimo; Quartini, Enrica; Cavitte, Marie G. P.; Tozer, Carly R.; Steinhage, Daniel; Urbini, Stefano; Corr, Hugh F. J.; van Ommen, Tas; Blankenship, Donald D.

    2017-08-01

    A high-resolution (1 km line spacing) aerogeophysical survey was conducted over a region near the East Antarctic Ice Sheet's Dome C that may hold a 1.5 Myr climate record. We combined new ice thickness data derived from an airborne coherent radar sounder with unpublished data that was in part unavailable for earlier compilations, and we were able to remove older data with high positional uncertainties. We generated a revised high-resolution digital elevation model (DEM) to investigate the potential for an old ice record in this region, and used laser altimetry to confirm a Cryosat-2 derived DEM for inferring the glaciological state of the candidate area. By measuring the specularity content of the bed, we were able to find an additional 50 subglacial lakes near the candidate site, and by Doppler focusing the radar data, we were able to map out the roughness of the bed at length scales of hundreds of meters. We find that the primary candidate region contains elevated rough topography interspersed with scattered subglacial lakes and some regions of smoother bed. Free subglacial water appears to be restricted from bed overlain by ice thicknesses of less than 3000 m. A site near the ice divide was selected for further investigation. The high resolution of this ice thickness data set also allows us to explore the nature of ice thickness uncertainties in the context of radar geometry and processing.

  17. In search of in-situ radiocarbon in Law Dome ice and firn

    CERN Document Server

    Smith, A M; Etheridge, D M; Lowe, D C; Hua, Q; Trudinger, C M; Zoppi, U; El-Cheikh, A

    2000-01-01

    Results of AMS radiocarbon measurements on CO and CO sub 2 separated from firn air directly pumped from the ice sheet, and on CO sub 2 separated from air extracted from ice cores by a dry grating technique, are presented. The firn air samples and ice cores used in this study were collected from the region of Law Dome, Antarctica. No evidence of in-situ sup 1 sup 4 CO sub 2 was found in the firn air samples or the ice core air samples from one site although a slight enhancement of sup 1 sup 4 CO above expected polar atmospheric concentrations was observed for some firn air samples. A clear in-situ sup 1 sup 4 CO sub 2 signal for ice pre-dating the radiocarbon bomb pulse was found, however, in air samples extracted from an ice core from a second site. We compare these results and propose an hypothesis to explain this apparent contradiction. The degree to which in-situ sup 1 sup 4 C is released from the ice crystals during trapping and bubble formation is considered and discussed. The selectivity of the dry grat...

  18. Air temperature and relative humidity in Dome Fuji Station buildings, East Antarctic ice sheet, in 2003

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    Takao Kameda

    2008-06-01

    Full Text Available In order to clarify the living condition in Dome Fuji Station in 2003, air temperature and relative humidity in the station were measured. Thermocouples with data logger and a ventilated psychrometer were used for the measurements. Average air temperature from February 11, 2003 to January 14, 2004 (missing period: July 19 to August 17 in the Dome Fuji Station buildings were as follows: Generator room 24.7℃, Dining room 23.5℃, Observation room 21.1℃, Dormitory room 18.2℃, Corridor 18.2℃, Food storage 8.2℃ and Old ice coring site -51.3℃. Average outside air temperature (1.5m height from the snow surface during the period was -54.4℃. A remarkable increase of outside air temperature (+30℃ at maximum due to a blocking high event was observed from October 31, 2003 to November 10, 2003 at Dome Fuji, during which increase of air temperature from 5 to 8°C in the station buildings was recorded. Snow on the station buildings was partly melted and some of the melted water penetrated into the station. This was the only time snow melted during the wintering over party's stay at the station. Average relative humidity in the station buildings obtained using a small humidifier was about 25%; the relative humidity without using the humidifier ranged from 9.0 to 22.9%.

  19. Ice Dome

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    National Aeronautics and Space Administration — A Design Study will be performed to assess the various design options, technical risks and cost effectiveness of this shelter concept. Also, detailed cost estimates...

  20. The EDC3 chronology for the EPICA Dome C ice core

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    F. Parrenin

    2007-08-01

    Full Text Available The EPICA (European Project for Ice Coring in Antarctica Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters above bedrock. Here we present the new EDC3 chronology, which is based on the use of 1 a snow accumulation and mechanical flow model, and 2 a set of independent age markers along the core. These are obtained by pattern matching of recorded parameters to either absolutely dated paleoclimatic records, or to insolation variations. We show that this new time scale is in excellent agreement with the Dome Fuji and Vostok ice core time scales back to 100 kyr within 1 kyr. Discrepancies larger than 3 kyr arise during MIS 5.4, 5.5 and 6, which points to anomalies in either snow accumulation or mechanical flow during these time periods. We estimate that EDC3 gives accurate event durations within 20% (2σ back to MIS11 and accurate absolute ages with a maximum uncertainty of 6 kyr back to 800 kyr.

  1. TALDICE-1 age scale of the Talos Dome deep ice core, East Antarctica

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    D. Buiron

    2011-01-01

    Full Text Available A new deep ice core drilling program, TALDICE, has been successfully handled by a European team at Talos Dome, in the Ross Sea sector of East Antarctica, down to 1620 m depth. Using stratigraphic markers and a new inverse method, we produce the first official chronology of the ice core, called TALDICE-1. We show that it notably improves an a priori chronology resulting from a one-dimensional ice flow model. It is in agreement with a posteriori controls of the resulting accumulation rate and thinning function along the core. An absolute uncertainty of only 300 yr is obtained over the course of the last deglaciation. This uncertainty remains lower than 600 yr over Marine Isotope Stage 3, back to 50 kyr BP. The phasing of the TALDICE ice core climate record with respect to the central East Antarctic plateau and Greenland records can thus be determined with a precision allowing for a discussion of the mechanisms at work at sub-millennial time scales.

  2. Construction on a new deep ice coring site at Dome Fuji Station -Operations carried out by the JARE-44 Dome Fuji overwintering team-

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    Takao Kameda

    2005-07-01

    Full Text Available Eight members of the 44th Japanese Antarctic Research Expedition (JARE-44 stayed at Dome Fuji Station (77°19′01″S, 39°42′11″E; 3810 m a.s.l.; ice thickness 3028±15 m; mean air temperature -54.4°C; lowest air temperature -79.7°C from January 19, 2003 to January 25, 2004 for glaciological, meteorological, and upper atmospheric observations, and for construction at a new ice coring site for deep ice coring. The construction was a continuation of the activities of JARE-43; JARE-44 primarily carried out interior work at the ice coring site. The following works were carried out during the overwintering period and are described in this paper: retrieval of casing pipes from the borehole, enlargement of the borehole, insertion of casing pipes into the borehole, movement of the winch system from the old to the new ice coring sites (44.5 m apart, floor construction, construction and preparation of a 10 m depth pit for the rotating mast, construction of stairs between the old and the new ice coring sites, construction of working tables, assembling the mast and the small goliath crane, setting up a lifter, testing the winch system, setting the winch for the chip collector, cable replacement for deep ice coring, assembling of a deep ice core drill, adjustment of a rotating mast, enlargement of caves for ice core storage, and general electrical work in the new ice coring site. The total working time for the above operations was 593.5 person-days. Since the average working time was 6 h/day, the total working time was 3561 person-hours. Preparations for borehole temperature measurements in a 2503 m borehole and the ice coring operation that was mainly conducted by the JARE-45 team are briefly described.

  3. 10Be evidence for the Matuyama-Brunhes geomagnetic reversal in the EPICA Dome C ice core.

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    Raisbeck, G M; Yiou, F; Cattani, O; Jouzel, J

    2006-11-02

    An ice core drilled at Dome C, Antarctica, is the oldest ice core so far retrieved. On the basis of ice flow modelling and a comparison between the deuterium signal in the ice with climate records from marine sediment cores, the ice at a depth of 3,190 m in the Dome C core is believed to have been deposited around 800,000 years ago, offering a rare opportunity to study climatic and environmental conditions over this time period. However, an independent determination of this age is important because the deuterium profile below a depth of 3,190 m depth does not show the expected correlation with the marine record. Here we present evidence for enhanced 10Be deposition in the ice at 3,160-3,170 m, which we interpret as a result of the low dipole field strength during the Matuyama-Brunhes geomagnetic reversal, which occurred about 780,000 years ago. If correct, this provides a crucial tie point between ice cores, marine cores and a radiometric timescale.

  4. A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores

    DEFF Research Database (Denmark)

    Johnsen, Sigfus Johann; Dahl-Jensen, Dorthe; Steffensen, Jørgen Peder

    2008-01-01

    We have proposed a method of deducing the chemical compounds found in deep polar ice cores by analyzing the balance between six major ions (Cl-, NO3 -, SO4 2-, Na+, Mg2+, and Ca2+). The method is demonstrated for the Holocene and last glacial maximum regions of the Dome Fuji and GRIP ice cores...... on individual salt inclusions. The abundances in the ice cores are shown to reflect differences in climatic periods (the acidic environment of the Holocene versus the reductive environment of the last glacial maximum) and regional conditions (the marine environment of Antarctica versus the continental...

  5. Atmospheric CO2 variations over the last three glacial-interglacial climatic cycles deduced from the Dome Fuji deep ice core, Antarctica using a wet extraction technique

    International Nuclear Information System (INIS)

    Kawamura, Kenji; Nakazawa, Takakiyo; Aoki, Shuji

    2003-01-01

    A deep ice core drilled at Dome Fuji, East Antarctica was analyzed for the CO 2 concentration using a wet extraction method in order to reconstruct its atmospheric variations over the past 320 kyr, which includes three full glacial-interglacial climatic cycles, with a mean time resolution of about 1.1 kyr. The CO 2 concentration values derived for the past 65 kyr are very close to those obtained from other Antarctic ice cores using dry extraction methods, although the wet extraction method is generally thought to be inappropriate for the determination of the CO 2 concentration. The comparison between the CO 2 and Ca 2+ concentrations deduced from the Dome Fuji core suggests that calcium carbonate emitted from lands was mostly neutralized in the atmosphere before reaching the central part of Antarctica, or that only a small part of calcium carbonate was involved in CO 2 production during the wet extraction process. The CO 2 concentration for the past 320 kyr deduced from the Dome Fuji core varies between 190 and 300 ppmv, showing clear glacial-interglacial variations similar to the result of the Vostok ice core. However, for some periods, the concentration values of the Dome Fuji core are higher by up to 20 ppmv than those of the Vostok core. There is no clear indication that such differences are related to variations of chemical components of Ca 2+ , microparticle and acidity of the Dome Fuji core

  6. High-resolution 129I bomb peak profile in an ice core from SE-Dome site, Greenland.

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    Bautista, Angel T; Miyake, Yasuto; Matsuzaki, Hiroyuki; Iizuka, Yoshinori; Horiuchi, Kazuho

    2018-04-01

    129 I in natural archives, such as ice cores, can be used as a proxy for human nuclear activities, age marker, and environmental tracer. Currently, there is only one published record of 129 I in ice core (i.e., from Fiescherhorn Glacier, Swiss Alps) and its limited time resolution (1-2 years) prevents the full use of 129 I for the mentioned applications. Here we show 129 I concentrations in an ice core from SE-Dome, Greenland, covering years 1956-1976 at a time resolution of ∼6 months, the most detailed record to date. Results revealed 129 I bomb peaks in years 1959, 1962, and 1963, associated to tests performed by the former Soviet Union, one year prior, in its Novaya Zemlya test site. All 129 I bomb peaks were observed in winter (1958.9, 1962.1, and 1963.0), while tritium bomb peaks, another prominent radionuclide associated with nuclear bomb testing, were observed in spring or summer (1959.3, and 1963.6; Iizuka et al., 2017). These results indicate that 129 I bomb peaks can be used as annual and seasonal age markers for these years. Furthermore, we found that 129 I recorded nuclear fuel reprocessing signals and that these can be potentially used to correct timing of estimated 129 I releases during years 1964-1976. Comparisons with other published records of 129 I in natural archives showed that 129 I can be used as common age marker and tracer for different types of records. Most notably, the 1963 129 I bomb peak can be used as common age marker for ice and coral cores, providing the means to reconcile age models and associated trends from the polar and tropical regions, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Glacier melting during lava dome growth at Nevado de Toluca volcano (Mexico): Evidences of a major threat before main eruptive phases at ice-caped volcanoes

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    Capra, L.; Roverato, M.; Groppelli, G.; Caballero, L.; Sulpizio, R.; Norini, G.

    2015-03-01

    Nevado de Toluca volcano is one of the largest stratovolcanoes in the Trans-Mexican Volcanic Belt. During Late Pleistocene its activity was characterized by large dome growth and subsequent collapse emplacing large block and ash flow deposits, intercalated by Plinian eruptions. Morphological and paleoclimate studies at Nevado de Toluca and the surrounding area evidenced that the volcano was affected by extensive glaciation during Late Pleistocene and Holocene. During the older recognized glacial period (27-60 ka, MIS 3), the glacier was disturbed by the intense magmatic and hydrothermal activity related to two dome extrusion episodes (at 37 ka and 28 ka). Glacier reconstruction indicates maximum ice thickness of 90 m along main valleys, as at the Cano ravines, the major glacial valley on the northern slope of the volcano. Along this ravine, both 37 and 28 ka block-and-ash deposits are exposed, and they directly overlay a fluviatile sequence, up to 40 m-thick, which 14C ages clearly indicate that their emplacement occurred just before the dome collapsed. These evidences point to a clear interaction between the growing dome and its hydrothermal system with the glacier. During dome growth, a large amount of melting water was released along major glacial valleys forming thick fluvioglacial sequences that were subsequently covered by the block-and-ash flow deposits generated by the collapse of the growing dome. Even though this scenario is no longer possible at the Nevado de Toluca volcano, the data presented here indicate that special attention should be paid to the possible inundation areas from fluviatile/lahar activity prior to the main magmatic eruption at ice-capped volcanoes.

  8. Evaluation of aerosol composition changes in the last 60 years around southeastern Greenland by analyzing micro-inclusions in the SE-Dome ice core using Raman spectroscopy.

    Science.gov (United States)

    Ando, T.; Iizuka, Y.; Ohno, H.; Sugiyama, S.

    2017-12-01

    Emission regulation of anthropogenic NOX and SOX since late 90's rather caused excess atmospheric ammonium (NH3) in agricultural regions (Warner et al., 2017, Geophys. Res. Lett.). The Arctic is one of the most sensitive areas for future warming. Aerosols in the Arctic are transported from the Northern Hemisphere and mostly experience wet deposition (Breider et al., 2014, Jour. of Geophys. Res.: Atmos.). Ice cores preserve past water-soluble aerosols. From these viewpoints, ice cores from the Arctic is suitable to evaluate recent variation in aerosol composition due to human activity in the Northern Hemisphere and aerosol transportation. We analyzed ion concentrations in the ice core samples from a southeastern dome in Greenland (SE-Dome). The concentrations increased for NH4+ and decreased for SO42- after late 90's. The NH4+ increasing trend is due to excess NH3 emission in North America. Cloud nuclei formation depends on chemical form of aerosols. Thus, differences in chemical forms of these ammonium aerosols in SE-Dome samples are important to evaluate the effect on climate change in Greenland. In this study, we identified the chemical form of aerosols (water-soluble inclusions) in the SE-Dome ice core by using micro-Raman spectroscopy. SE-Dome ice core samples were collected in 2015 and enabled us to reconstruct seasonal variation owing to extremely higher accumulation rate ( 1m/yr.). The ice samples were sublimated and accumulated inclusions on the Ni sheets in a clean booth under -22 degrees Celsius. We identified CaSO4, Na2SO4, (NH4)2SO4, NaNO3, NH4NO3 by Raman spectra. This is the first report to identify ammonium salts ((NH4)2SO4 and NH4NO3) from ice core sample. In the summer samples, the relative abundances of CaSO4 and NaNO3 are lower but (NH4)2SO4 are higher than those in the spring samples. NH4+ rapidly react with SO24- under higher temperature. Higher concentration of NH3 in the warmest season possibly enhanced the formation of (NH4)2SO4 in North

  9. High-resolution records of the beryllium-10 solar activity proxy in ice from Law Dome, East Antarctica: measurement, reproducibility and principal trends

    Directory of Open Access Journals (Sweden)

    J. B. Pedro

    2011-07-01

    Full Text Available Three near-monthly resolution 10Be records are presented from the Dome Summit South (DSS ice core site, Law Dome, East Antarctica. The chemical preparation and Accelerator Mass Spectrometer (AMS measurement of these records is described. The reproducibility of 10Be records at DSS is assessed through intercomparison of the ice core data with data from two previously published and contemporaneous snow pits. We find generally good agreement between the five records, comparable to that observed between other trace chemical records from the site. This result allays concerns raised by a previous Antarctic study (Moraal et al., 2005 about poor reproducibility of ice core 10Be records. A single composite series is constructed from the three ice cores providing a monthly-resolved record of 10Be concentrations at DSS over the past decade (1999 to 2009. To our knowledge, this is the first published ice core data spanning the recent exceptional solar minimum of solar cycle 23. 10Be concentrations are significantly correlated to the cosmic ray flux recorded by the McMurdo neutron monitor (rxy = 0.64, with 95 % CI of 0.53 to 0.71, suggesting that solar modulation of the atmospheric production rate may explain up to ~40 % of the variance in 10Be concentrations at DSS. Sharp concentration peaks occur in most years during the summer-to-autumn, possibly caused by stratospheric incursions. Our results underscore the presence of both production and meteorological signals in ice core 10Be data.

  10. Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates

    Science.gov (United States)

    Petrenko, Vasilii V.; Severinghaus, Jeffrey P.; Schaefer, Hinrich; Smith, Andrew M.; Kuhl, Tanner; Baggenstos, Daniel; Hua, Quan; Brook, Edward J.; Rose, Paul; Kulin, Robb; Bauska, Thomas; Harth, Christina; Buizert, Christo; Orsi, Anais; Emanuele, Guy; Lee, James E.; Brailsford, Gordon; Keeling, Ralph; Weiss, Ray F.

    2016-03-01

    Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from ;old; carbon sources such as permafrost and marine CH4 clathrates. 14C in trapped carbon dioxide (14CO2) can be used for absolute dating of ice cores. In situ produced cosmogenic 14C in carbon monoxide (14CO) can potentially be used to reconstruct the past cosmic ray flux and past solar activity. Unfortunately, the trapped atmospheric and in situ cosmogenic components of 14C in glacial ice are difficult to disentangle and a thorough understanding of the in situ cosmogenic component is needed in order to extract useful information from ice core 14C. We analyzed very large (≈1000 kg) ice samples in the 2.26-19.53 m depth range from the ablation zone of Taylor Glacier, Antarctica, to study in situ cosmogenic production of 14CH4 and 14CO. All sampled ice is >50 ka in age, allowing for the assumption that most of the measured 14C originates from recent in situ cosmogenic production as ancient ice is brought to the surface via ablation. Our results place the first constraints on cosmogenic 14CH4 production rates and improve on prior estimates of 14CO production rates in ice. We find a constant 14CH4/14CO production ratio (0.0076 ± 0.0003) for samples deeper than 3 m, which allows the use of 14CO for correcting the 14CH4 signals for the in situ cosmogenic component. Our results also provide the first unambiguous confirmation of 14C production by fast muons in a natural setting (ice or rock) and suggest that the 14C production rates in ice commonly used in the literature may be too high.

  11. A refined TALDICE-1a age scale from 55 to 112 ka before present for the Talos Dome ice core based on high-resolution methane measurements

    Directory of Open Access Journals (Sweden)

    S. Schüpbach

    2011-09-01

    Full Text Available A precise synchronization of different climate records is indispensable for a correct dynamical interpretation of paleoclimatic data. A chronology for the TALDICE ice core from the Ross Sea sector of East Antarctica has recently been presented based on methane synchronization with Greenland and the EDC ice cores and δ18Oice synchronization with EDC in the bottom part (TALDICE-1. Using new high-resolution methane data obtained with a continuous flow analysis technique, we present a refined age scale for the age interval from 55–112 thousand years (ka before present, where TALDICE is synchronized with EDC. New and more precise tie points reduce the uncertainties of the age scale from up to 1900 yr in TALDICE-1 to below 1100 yr over most of the refined interval and shift the Talos Dome dating to significantly younger ages during the onset of Marine Isotope Stage 3. Thus, discussions of climate dynamics at sub-millennial time scales are now possible back to 110 ka, in particular during the inception of the last ice age. Calcium data of EDC and TALDICE are compared to show the impact of the refinement to the synchronization of the two ice cores not only for the gas but also for the ice age scale.

  12. Anomalous flow below 2700 m in the EPICA Dome C ice core detected using δ18O of atmospheric oxygen measurements

    Directory of Open Access Journals (Sweden)

    M. Leuenberger

    2007-06-01

    Full Text Available While there are no indications of mixing back to 800 000 years in the EPICA Dome C ice core record, comparison with marine sediment records shows significant differences in the timing and duration of events prior to stage 11 (~430 ka, thousands of years before 1950. A relationship between the isotopic composition of atmospheric oxygen (δ18O of O2, noted δ18Oatm and daily northern hemisphere summer insolation has been observed for the youngest four climate cycles. Here we use this relationship with new δ18O of O2 measurements to show that anomalous flow in the bottom 500 m of the core distorts the duration of events by up to a factor of 2. By tuning δ18Oatm to orbital precession we derive a corrected thinning function and present a revised age scale for the interval corresponding to Marine Isotope Stages 11–20 in the EPICA Dome C ice core. Uncertainty in the phasing of δ18Oatm with respect to insolation variations in the precession band limits the accuracy of this new agescale to ±6 kyr (thousand of years. The previously reported ~30 kyr duration of interglacial stage 11 is unchanged. In contrast, the duration of stage 15.1 is reduced by a factor of 2, from 31 to 16 kyr.

  13. Precipitation and synoptic regime in two extreme years 2009 and 2010 at Dome C, Antarctica – implications for ice core interpretation

    Directory of Open Access Journals (Sweden)

    E. Schlosser

    2016-04-01

    Full Text Available At the East Antarctic deep ice core drilling site Dome C, daily precipitation measurements were initiated in 2006 and are being continued until today. The amounts and stable isotope ratios of the precipitation samples as well as crystal types are determined. Within the measuring period, the two years 2009 and 2010 showed striking contrasting temperature and precipitation anomalies, particularly in the winter seasons. The reasons for these anomalies are analysed using data from the mesoscale atmospheric model WRF (Weather Research and Forecasting Model run under the Antarctic Mesoscale Prediction System (AMPS. 2009 was relatively warm and moist due to frequent warm air intrusions connected to amplification of Rossby waves in the circumpolar westerlies, whereas the winter of 2010 was extremely dry and cold. It is shown that while in 2010 a strong zonal atmospheric flow was dominant, in 2009 an enhanced meridional flow prevailed, which increased the meridional transport of heat and moisture onto the East Antarctic plateau and led to a number of high-precipitation/warming events at Dome C. This was also evident in a positive (negative SAM (Southern Annular Mode index and a negative (positive ZW3 (zonal wave number three index during the winter months of 2010 (2009. Changes in the frequency or seasonality of such event-type precipitation can lead to a strong bias in the air temperature derived from stable water isotopes in ice cores.

  14. Sulphate and chloride aerosols during Holocene and last glacial periods preserved in the Talos Dome Ice Core, a peripheral region of Antarctica

    Directory of Open Access Journals (Sweden)

    Yoshinori Iizuka

    2013-04-01

    Full Text Available Antarctic ice cores preserve the record of past aerosols, an important proxy of past atmospheric chemistry. Here we present the aerosol compositions of sulphate and chloride particles in the Talos Dome (TD ice core from the Holocene and Last Glacial Period. We find that the main salt types of both periods are NaCl, Na2SO4 and CaSO4, indicating that TD ice contains relatively abundant sea salt (NaCl from marine primary particles. By evaluating the molar ratio of NaCl to Na2SO4, we show that about half of the sea salt does not undergo sulphatisation during late Holocene. Compared to in inland Antarctica, the lower sulphatisation rate at TD is probably due to relatively little contact between sea salt and sulphuric acid. This low contact rate can be related to a reduced time of reaction for marine-sourced aerosol before reaching TD and/or to a reduced post-depositional effect from the higher accumulation rate at TD. Many sulphate and chloride salts are adhered to silicate minerals. The ratio of sulphate-adhered mineral to particle mass and the corresponding ratio of chloride-adhered mineral both increase with increasing dust concentration. Also, the TD ice appears to contain Ca(NO32 or CaCO3 particles, thus differing from aerosol compositions in inland Antarctica, and indicating the proximity of peripheral regions to marine aerosols.

  15. Nitrate deposition and preservation in the snowpack along a traverse from coast to the ice sheet summit (Dome A) in East Antarctica

    Science.gov (United States)

    Shi, Guitao; Hastings, Meredith G.; Yu, Jinhai; Ma, Tianming; Hu, Zhengyi; An, Chunlei; Li, Chuanjin; Ma, Hongmei; Jiang, Su; Li, Yuansheng

    2018-04-01

    Antarctic ice core nitrate (NO3-) can provide a unique record of the atmospheric reactive nitrogen cycle. However, the factors influencing the deposition and preservation of NO3- at the ice sheet surface must first be understood. Therefore, an intensive program of snow and atmospheric sampling was made on a traverse from the coast to the ice sheet summit, Dome A, East Antarctica. Snow samples in this observation include 120 surface snow samples (top ˜ 3 cm), 20 snow pits with depths of 150 to 300 cm, and 6 crystal ice samples (the topmost needle-like layer on Dome A plateau). The main purpose of this investigation is to characterize the distribution pattern and preservation of NO3- concentrations in the snow in different environments. Results show that an increasing trend of NO3- concentrations with distance inland is present in surface snow, and NO3- is extremely enriched in the topmost crystal ice (with a maximum of 16.1 µeq L-1). NO3- concentration profiles for snow pits vary between coastal and inland sites. On the coast, the deposited NO3- was largely preserved, and the archived NO3- fluxes are dominated by snow accumulation. The relationship between the archived NO3- and snow accumulation rate can be depicted well by a linear model, suggesting a homogeneity of atmospheric NO3- levels. It is estimated that dry deposition contributes 27-44 % of the archived NO3- fluxes, and the dry deposition velocity and scavenging ratio for NO3- were relatively constant near the coast. Compared to the coast, the inland snow shows a relatively weak correlation between archived NO3- and snow accumulation, and the archived NO3- fluxes were more dependent on concentration. The relationship between NO3- and coexisting ions (nssSO42-, Na+ and Cl-) was also investigated, and the results show a correlation between nssSO42- (fine aerosol particles) and NO3- in surface snow, while the correlation between NO3- and Na+ (mainly associated with coarse aerosol particles) is not

  16. IRON DOME

    African Journals Online (AJOL)

    6 Israeli Navy 'First Arm of the Sea: The Successful Interception of the Iron Dome Rocket .... sky to destroy them whilst in flight to minimise civilian casualties. ..... Including The Moon and Celestial Bodies.53 Demeyere further emphasises the.

  17. A comparison of the present and last interglacial periods in six Antarctic ice cores

    Directory of Open Access Journals (Sweden)

    V. Masson-Delmotte

    2011-04-01

    Full Text Available We compare the present and last interglacial periods as recorded in Antarctic water stable isotope records now available at various temporal resolutions from six East Antarctic ice cores: Vostok, Taylor Dome, EPICA Dome C (EDC, EPICA Dronning Maud Land (EDML, Dome Fuji and the recent TALDICE ice core from Talos Dome. We first review the different modern site characteristics in terms of ice flow, meteorological conditions, precipitation intermittency and moisture origin, as depicted by meteorological data, atmospheric reanalyses and Lagrangian moisture source diagnostics. These different factors can indeed alter the relationships between temperature and water stable isotopes. Using five records with sufficient resolution on the EDC3 age scale, common features are quantified through principal component analyses. Consistent with instrumental records and atmospheric model results, the ice core data depict rather coherent and homogenous patterns in East Antarctica during the last two interglacials. Across the East Antarctic plateau, regional differences, with respect to the common East Antarctic signal, appear to have similar patterns during the current and last interglacials. We identify two abrupt shifts in isotopic records during the glacial inception at TALDICE and EDML, likely caused by regional sea ice expansion. These regional differences are discussed in terms of moisture origin and in terms of past changes in local elevation histories, which are compared to ice sheet model results. Our results suggest that elevation changes may contribute significantly to inter-site differences. These elevation changes may be underestimated by current ice sheet models.

  18. Dome craters on Ganymede

    International Nuclear Information System (INIS)

    Moore, J.M.; Malin, M.C.

    1987-01-01

    Voyager observations reveal impact craters on Ganymede that are characterized by the presence of broad, high albedo, topographic domes situated within a central pit. Fifty-seven craters with central domes were identified in images covering approx. 50% of the surface. Owing to limitations in resolution, and viewing and illumination angles, the features identified are most likely a subset of dome craters. The sample appears to be sufficiently large to infer statistically meaningful trends. Dome craters appear to fall into two distinct populations on plots of the ratio of dome diameter to crater rim diameter, large-dome craters and small-dome craters. The two classes are morphologically distinct from one another. In general, large dome craters show little relief and their constituent landforms appear subdued with respect to fresh craters. The physical attributes of small-dome craters are more sharply defined, a characteristic they share with young impact craters of comparable size observed elsewhere in the solar system. Both types of dome craters exhibit central pits in which the dome is located. As it is difficult to produce domes by impact and/or erosional processes, an endogenic origin for the domes is reasonably inferred. Several hypotheses for their origin are proposed. These hypotheses are briefly reviewed

  19. From Taylor series to Taylor models

    International Nuclear Information System (INIS)

    Berz, Martin

    1997-01-01

    An overview of the background of Taylor series methods and the utilization of the differential algebraic structure is given, and various associated techniques are reviewed. The conventional Taylor methods are extended to allow for a rigorous treatment of bounds for the remainder of the expansion in a similarly universal way. Utilizing differential algebraic and functional analytic arguments on the set of Taylor models, arbitrary order integrators with rigorous remainder treatment are developed. The integrators can meet pre-specified accuracy requirements in a mathematically strict way, and are a stepping stone towards fully rigorous estimates of stability of repetitive systems

  20. From Taylor series to Taylor models

    International Nuclear Information System (INIS)

    Berz, M.

    1997-01-01

    An overview of the background of Taylor series methods and the utilization of the differential algebraic structure is given, and various associated techniques are reviewed. The conventional Taylor methods are extended to allow for a rigorous treatment of bounds for the remainder of the expansion in a similarly universal way. Utilizing differential algebraic and functional analytic arguments on the set of Taylor models, arbitrary order integrators with rigorous remainder treatment are developed. The integrators can meet pre-specified accuracy requirements in a mathematically strict way, and are a stepping stone towards fully rigorous estimates of stability of repetitive systems. copyright 1997 American Institute of Physics

  1. Taylor-Made Libraries

    Science.gov (United States)

    Lonergan, David

    2011-01-01

    Frederick Winslow Taylor (1856-1915) was an efficiency expert whose concerns were less about avoiding worker fatigue and more about increasing profit margins by any means necessary. Taylor was devoted to finding the One Best Way to carry out a task and then training workers to do that task unvaryingly; attempts by employees to improve their own…

  2. Snow precipitation at four ice core sites in East Antarctica: provenance, seasonality and blocking factors

    Energy Technology Data Exchange (ETDEWEB)

    Scarchilli, Claudio [ENEA, Rome (Italy); Universita degli studi di Trieste, Trieste (Italy); Frezzotti, Massimo; Ruti, Paolo Michele [ENEA, Rome (Italy)

    2011-11-15

    Snow precipitation is the primary mass input to the Antarctic ice sheet and is one of the most direct climatic indicators, with important implications for paleoclimatic reconstruction from ice cores. Provenance of precipitation and the dynamic conditions that force these precipitation events at four deep ice core sites (Dome C, Law Dome, Talos Dome, and Taylor Dome) in East Antarctica were analysed with air mass back trajectories calculated using the Lagrangian model and the mean composite data for precipitation, geopotential height and wind speed field data from the European Centre for Medium Range Weather Forecast from 1980 to 2001. On an annual basis, back trajectories showed that the Atlantic-Indian and Ross-Pacific Oceans were the main provenances of precipitation in Wilkes Land (80%) and Victoria Land (40%), respectively, whereas the greatest influence of the ice sheet was on the interior near the Vostok site (80%) and in the Southwest Ross Sea (50%), an effect that decreased towards the coast and along the Antarctic slope. Victoria Land received snowfall atypically with respect to other Antarctica areas in terms of pathway (eastern instead of western), seasonality (summer instead of winter) and velocity (old air age). Geopotential height patterns at 500 hPa at low (>10 days) and high (2-6 days) frequencies during snowfall cycles at two core sites showed large positive anomalies at low frequencies developing in the Tasman Sea-Eastern Indian Ocean at higher latitudes (60-70 S) than normal. This could be considered part of an atmospheric blocking event, with transient eddies acting to decelerate westerlies in a split region area and accelerate the flow on the flanks of the low-frequency positive anomalies. (orig.)

  3. LA-ICP-MS Results: 3 Siple Dome A Glacial Age Archives, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains the results of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) performed on an archive of the Siple Dome A ice core...

  4. Repainting, modifying, smashing Taylorism

    NARCIS (Netherlands)

    H.D. Pruijt (Hans)

    2000-01-01

    textabstractAbstract Survey data show that post-Tayloristic production concepts are not developing to the extent that many researchers had originally expected. It also is inadequate to portray post-Taylorism as a development that is happening, but just slower than expected. This is inadequate

  5. Acoustic of monolithic dome structures

    Directory of Open Access Journals (Sweden)

    Mostafa Refat Ismail

    2018-03-01

    The interior of monolithic domes have perfect, concave shapes to ensure that sound travels through the dome and perfectly collected at different vocal points. These dome structures are utilized for domestic use because the scale allows the focal points to be positioned across daily life activities, thereby affecting the sonic comfort of the internal space. This study examines the various acoustic treatments and parametric configurations of monolithic dome sizes. A geometric relationship of acoustic treatment and dome radius is established to provide architects guidelines on the correct selection of absorption needed to maintain the acoustic comfort of these special spaces.

  6. Repainting, modifying, smashing Taylorism

    OpenAIRE

    Pruijt, Hans

    2000-01-01

    textabstractAbstract Survey data show that post-Tayloristic production concepts are not developing to the extent that many researchers had originally expected. It also is inadequate to portray post-Taylorism as a development that is happening, but just slower than expected. This is inadequate because there are counter-tendencies: the resurgence of the assembly line in the highly paradigmatic automobile assembly; the rise of the McDonalds-type organization; and continuing skills-replacing auto...

  7. Solar radiation on domed roofs

    Energy Technology Data Exchange (ETDEWEB)

    Faghih, Ahmadreza K.; Bahadori, Mehdi N. [School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran)

    2009-11-15

    Solar radiation received and absorbed by four domed roofs was estimated and compared with that of a flat roof. The domed roofs all had the same base areas, and equal to that of the flat roof. One of the roofs considered was the dome of the St. Peter's Church in Rome. Compared with the other roofs considered, this dome had a higher aspect ratio. It was found that all domed roofs received more solar radiation than the flat roof. Considering glazed tiles to cover a selected dome in Iran and the dome of the St. Peter's Church, it was found that the solar radiation absorbed by these roofs is reduced appreciably. In the case of the dome of St. Peter's Church, the amount of radiation absorbed was roughly equal to that absorbed by the comparable flat roof in the warm months. In the case of the glazed reference dome located in Yazd, Iran (a city with very high solar radiation), the radiation absorbed was less than that of flat roof at all times. In addition to aesthetics, this may be a reason for employing glazed tiles to cover the domes of all mosques, shrines, and other large buildings in Iran. (author)

  8. Taylor dispersion of nanoparticles

    Science.gov (United States)

    Balog, Sandor; Urban, Dominic A.; Milosevic, Ana M.; Crippa, Federica; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2017-08-01

    The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced "industrial" particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori.

  9. Iron fluxes to Talos Dome, Antarctica, over the past 200 kyr

    Directory of Open Access Journals (Sweden)

    P. Vallelonga

    2013-03-01

    Full Text Available Atmospheric fluxes of iron (Fe over the past 200 kyr are reported for the coastal Antarctic Talos Dome ice core, based on acid leachable Fe concentrations. Fluxes of Fe to Talos Dome were consistently greater than those at Dome C, with the greatest difference observed during interglacial climates. We observe different Fe flux trends at Dome C and Talos Dome during the deglaciation and early Holocene, attributed to a combination of deglacial activation of dust sources local to Talos Dome and the reorganisation of atmospheric transport pathways with the retreat of the Ross Sea ice shelf. This supports similar findings based on dust particle sizes and fluxes and Rare Earth Element fluxes. We show that Ca and Fe should not be used as quantitative proxies for mineral dust, as they all demonstrate different deglacial trends at Talos Dome and Dome C. Considering that a 20 ppmv decrease in atmospheric CO2 at the coldest part of the last glacial maximum occurs contemporaneously with the period of greatest Fe and dust flux to Antarctica, we confirm that the maximum contribution of aeolian dust deposition to Southern Ocean sequestration of atmospheric CO2 is approximately 20 ppmv.

  10. Editorial: Howard Taylor Ricketts

    Directory of Open Access Journals (Sweden)

    Facultad de Medicina Revista

    1941-05-01

    Full Text Available Howard Taylor Ricketts nació en Findlay (Ohio el 9 de febrero de 1871. Pasó su niñez en Nebraska, recibió su título de bachiller en la Universidad de ese Estado, en 1894 y se graduó de médico en Northwestern University, en 1897. Hizo su internado en el Cook-County de Chicago. Practicó estdios especiales de dermatología en el Rush Medical College durante dos años. En 1900 contrajo matrimonio con Myra Tubbs, inteligente mujer que colaboró en sus trabajos con rara devoción, ardiente interés y constante estímulo.

  11. Atomic Power | Taylor | Zede Journal

    African Journals Online (AJOL)

    Zede Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 3 (1968) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Atomic Power. D Taylor. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT ...

  12. Electrochemical Analysis of Taylor Vortices.

    Czech Academy of Sciences Publication Activity Database

    Wouahbi, F.; Allaf, K.; Sobolík, Václav

    2007-01-01

    Roč. 37, 1 (2007) , s. 57-62 ISSN 0021-891X Institutional research plan: CEZ:AV0Z40720504 Keywords : electrodiffusion method * taylor vortices * three-segment electrode Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.417, year: 2007

  13. Who believes in the Taylor Principle?

    DEFF Research Database (Denmark)

    Stadtmann, Georg; Pierdzioch; Rülke

    2012-01-01

    The Livingston survey data are used to investigate whether economists’ forecasts are consistent with the Taylor principle. Consistency with the Taylor principle is strong for academics and Federal Reserve economists, and less strong for private-sector economists.......The Livingston survey data are used to investigate whether economists’ forecasts are consistent with the Taylor principle. Consistency with the Taylor principle is strong for academics and Federal Reserve economists, and less strong for private-sector economists....

  14. Seasonal variability in the input of lead, barium and indium to Law Dome, Antarctica

    DEFF Research Database (Denmark)

    Burn-Nunes...[], L.J.; Vallelonga, Paul Travis; Loss, R.D.

    2011-01-01

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been determined at monthly resolution in five Law Dome (coastal Eastern Antarctica) ice core sections dated from similar to 1757 AD to similar to 1898 AD. 'Natural' background Pb concentrations...

  15. Site characterization plan: Gulf Coast salt domes

    International Nuclear Information System (INIS)

    1983-12-01

    The National Waste Terminal Storage (NWTS) program of the US Department of Energy (DOE) is responsible for developing technology and providing facilities for safe, environmentally acceptable, permanent disposal of high-level nuclear waste. The Office of Nuclear Waste Isolation has been intensively investigating Gulf Coast Salt Dome Basin salt domes and bedded salt in Texas and Utah since 1978. In the Gulf Coast, the application of screening criteria in the region phase led to selection of eight domes for further study in the location phase. Further screening in the area phase identified four domes for more intensive study in the location phase: Oakwood Dome, Texas; Vacherie Dome, Louisiana; and Richton Dome and Cypress Creek Dome, Mississippi. For each dome, this Site Characterization Plan identifies specific hydrologic, geologic, tectonic, geochemical, and environmental key issues that are related to the DOE/NWTS screening criteria or affect the feasibility of constructing an exploratory shaft. The Site Characterization Plan outlines studies need to: (1) resolve issues sufficiently to allow one or more salt domes to be selected and compared to bedded salt sites in order to determine a prime salt site for an exploratory shaft; (2) conduct issue-related studies to provide a higher level of confidence that the preferred salt dome site is viable for construction of an exploratory shaft; and (3) provide a vehicle for state input to issues. Extensive references, 7 figures, 20 tables

  16. Lunar domes properties and formation processes

    CERN Document Server

    Lena, Raffaello; Phillips, Jim; Chiocchetta, Maria Teresa

    2013-01-01

    Lunar domes are structures of volcanic origin which are usually difficult to observe due to their low heights. The Lunar Domes Handbook is a reference work on these elusive features. It provides a collection of images for a large number of lunar domes, including telescopic images acquired with advanced but still moderately intricate amateur equipment as well as recent orbital spacecraft images. Different methods for determining the morphometric properties of lunar domes (diameter, height, flank slope, edifice volume) from image data or orbital topographic data are discussed. Additionally, multispectral and hyperspectral image data are examined, providing insights into the composition of the dome material. Several classification schemes for lunar domes are described, including an approach based on the determined morphometric quantities and spectral analyses. Furthermore, the book provides a description of geophysical models of lunar domes, which yield information about the properties of the lava from which the...

  17. Taylor Hydro plant goes live

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    The 12.75 MW Taylor Hydroelectric Plant in Magrath, Alberta, synchronized its generator with the Alberta Power Grid and began production in April 2000. The plant is located on Government of Alberta irrigation works and is owned by Canadian Hydro Developers. During the irrigation season the plant will generate approximately 40 million kilowatt hours of zero-emission 'green' power for consumption, enough to power 5,000 homes for a year. The Taylor plant is a joint venture with EPCOR Power Development Corporation, a wholly-owned subsidiary of EPCOR Inc., the City of Edmonton utility. Canadian Hydro Developers also owns a 19 MW wind plant and a 6 MW gas plant in Alberta and five other 'run of river' hydro plants in Ontario and British Columbia. The company is committed to the concept of low-impact power generation; its ownership of wind run-of-river hydro and gas-fired facilities is proof of that commitment

  18. Micromixer based on Taylor dispersion

    International Nuclear Information System (INIS)

    Yang, H; Nguyen, N-T; Huang, X

    2006-01-01

    This paper reports an analytical model, the fabrication and the characterization of a polymeric micromixer based on Taylor dispersion. Due to the distributed velocity field over the channel cross section, the effective dispersion in axial direction in a microchannel is much stronger than the pure molecular diffusion. In our work, squential segmentation was used in the micromixer for improving mixing in a microchannel. The micromixer was designed and fabricated based on lamination of five 100-μm-thick polymer sheets. Rubber valve seats were embedded between the forth and the fifth layers. The polymer layers were machined using a CO 2 laser. The lamination of the five layers was carried out by a commercial hot laminator (Aurora LM-450HC). External solenoid actuators are used for closing the valves at the mixer inlets. The experimental results confirm the effect of Taylor dispersion. Mixing ratio can be adjusted by pulse width modulation of the control signal of the solenoids

  19. Generalization of the Taylor Principle

    International Nuclear Information System (INIS)

    Jensen, T.H.

    1986-01-01

    The usual Taylor Principle can in general only be applied when the system is closed. This paper describes a suggestion of a generalization to cover the case that the plasma is surrounded by a conducting shell with narrow gaps where the external circuits connected to the gaps consist of just inductors. The suggested constraint of the generalized Taylor Principle is that no helicity is absorbed by the plasma. The usual assumption that the stable Taylor Equilibrium is that for which the magnetic energy in the plasma region as well as in the external inductors is minimized subject to the above constraint, again leads to a unique configuration. It is found that this configuration is dependent upon the inductances of the external inductors. For the sake of conceptual simplicity, consider a closed shell of conducting material. The interior of the shell may be divided into various compartments only corrected through narrow gaps in the conducting walls between these compartments. They assume plasma present in only one of the compartments; the neighboring compartments represent the external inductors connected across the gaps of the plasma compartment

  20. Monitoring current rates of salt dome movement

    International Nuclear Information System (INIS)

    Thoms, R.L.; Manning, T.A.

    1977-01-01

    The tectonic stability of salt domes is a major concern for long-term domal storage of noxious wastes. A necessary phase of the many faceted dome storage study includes obtaining a measure of current vertical movement of any potential storage dome. This information then can be combined with data obtained from studies involving geologic time scales so as to provide a history of dome movement that includes present time. A system of instrumentation for monitoring current rates of dome movement is described. Complimentary finite element modelling of plausible dome movement also is presented. The proposed instrumentation system includes tiltmeters, precise levelling, laser ranging, and monitoring of microseisms. Thus, components of rotation and vertical and horizontal movements at the ground surface over a dome can be monitored. In addition, a measure of dome movement also may be obtained acoustically. The finite element modelling furnishes an aid for: (1) locating instrument sites over a dome so as to maximize instrument sensitivity, and (2) interpreting data obtained from the instrumentation system. An example of tiltmeter installation and operation over a dome in northwest Louisiana is included. Typical tiltmeter output is presented and discussed

  1. What factors control superficial lava dome explosivity?

    Science.gov (United States)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J

    2015-09-30

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management.

  2. Thermal influences on spontaneous rock dome exfoliation

    Science.gov (United States)

    Collins, Brian D.; Stock, Greg M.; Eppes, Martha C.; Lewis, Scott W.; Corbett, Skye C.; Smith, Joel B.

    2018-01-01

    Rock domes, with their onion-skin layers of exfoliation sheets, are among the most captivating landforms on Earth. Long recognized as integral in shaping domes, the exact mechanism(s) by which exfoliation occurs remains enigmatic, mainly due to the lack of direct observations of natural events. In August 2014, during the hottest days of summer, a granitic dome in California, USA, spontaneously exfoliated; witnesses observed extensive cracking, including a ~8000 kg sheet popping into the air. Subsequent exfoliation episodes during the following two summers were recorded by instrumentation that captured—for the first time—exfoliation deformation and stress conditions. Here we show that thermal cycling and cumulative dome surface heating can induce subcritical cracking that culminates in seemingly spontaneous exfoliation. Our results indicate that thermal stresses—largely discounted in dome formation literature—can play a key role in triggering exfoliation and therefore may be an important control for shaping domes worldwide.

  3. Dissolution of the Mors salt dome

    International Nuclear Information System (INIS)

    Lindstroem Jensen, K.E.

    1982-01-01

    Regardless of the interpretation of the measured salinity profiles above the Mors salt dome, they can at most be the result of dissolution rates of about 0.004 mm per year. This means that it would take more than 2.5 mill. years to dissolve 10 m of salt. Variations in groun water velocity and cap rock porosity will not significantly change this condition. The stability of the Mors salt dome is therefore not affected by dissolution of the dome. (EG)

  4. PERSIAN DOMES: HISTORY, MORPHOLOGY AND TYPOLOGIES

    Directory of Open Access Journals (Sweden)

    Maryam Ashkan

    2009-11-01

    Full Text Available Persian master builders had introduced an architectural innovation which had an imperishable effect on dome architecture in the Middle East and Central Asia: surmounting a dome on squinches. This paper aims to provide a broader perspective of Persian domes as the most significant feature of Eastern domes in the Middle East. As opposed to previous general historic studies, this paper introduces a new analytical approach directed towards analysis of architectural concepts and stylistic attributes of Persian domes based on an epistemological premise of their space syntax. By analytic reviewing of examples, the paper addresses the origin of Persian domes, their formal morphological constitutions, and their typological forms based on the diversity of the external shell over the specific timeline, from the pre-Islamic era through the Qajar period in Iran. The study of the Persian dome’s characteristics can illustrate undiscovered information about the essences of developing dome constructions in the Middle East. It can also establish new design standards regarding the frameworks of domical building configurations to be used for creating typological diversity in dome design and to renew the morphological principles of the traditional dome compositions in contemporary architectural designs. Finally, the insights gained can inform conservation efforts on domical structures in the region and elsewhere.

  5. Annually-resolved temperature reconstructions of the past 2000 years from Dome-Fuji, East Antarctica

    Science.gov (United States)

    Motizuki, Yuko; Takahashi, Kazuya; Nakai, Yoichi; Motoyama, Hideaki

    2016-04-01

    We present annually-resolved temperature and SST reconstructions of the past 2000 years based on water (oxygen and deuterium) isotope measurement on a shallow ice core drilled in 2010 at Dome Fuji station, East Antarctica. These time series records will be an essential contribution to the PAGES 2k project from sparse data area in Antarctica. Dome Fuji station is located on a summit of Dronning Maud Land at an altitude of 3810 m a.s.l. (above sea level) (77o19'01'' S, 39o42'12'' E) in East Antarctica. The 10 m depth mean snow temperature at Dome Fuji is -57.3oC1). The inland area around Dome Fuji has been recognized to be especially unique: The snow and ice there contain much stratospheric information. The direct evidence for this comes from tritium contents originated from the nuclear bomb tests in the 1960s; the tritium fallout at the Dome Fuji site is outstandingly high among 16 snow pit samples widely collected over Antarctica2). To date the concerned Dome Fuji ice core, we applied volcanic signature matching to transfer the West Antarctic Ice Sheet (WAIS) Divide ice core chronology constructed by annual layer counting as used in the study by Sigl et al. (2014)3). In our presentation, we confine ourselves to discuss the oscillation periodicity that we observed in the oxygen isotope record in our data: The periods of approximately 10, 20, and 200 years were found. We will present the time series analyses for this in detail, and will discuss the origin of this periodicity. References: 1) Kameda, T., Motoyama, H., Fujita, S., and Takahashi, S.: "Past temporal and spatial variability of surface mass balance at Dome Fuji", East Antarctica, by the stake method from 1995 to 2006, J. Glaciol., 54, 107-116, 2008. 2) Fourre, E., Jean-Baptiste, P., Dapoigny, A., Baumier, D., Petit, J.-R., and Jouzel, J.: "Past and recent tritium levels in Arctic and Antarctic polar caps", Earth Planet. Sc. Lett., 245, 56-64, 2006. 3) Sigl, M., J. McConnell, M. Toohey, M. Curran, S. Das, R

  6. Taylor dispersion on a fractal

    International Nuclear Information System (INIS)

    Mazo, R.M.

    1998-01-01

    Taylor dispersion is the greatly enhanced diffusion in the direction of a fluid flow caused by ordinary diffusion in directions orthogonal to the flow. It is essential that the system be bounded in space in the directions orthogonal to the flow. We investigate the situation where the medium through which the flow occurs has fractal properties so that diffusion in the orthogonal directions is anomalous and non-Fickian. The effective diffusion in the flow direction remains normal; its width grows proportionally with the time. However, the proportionality constant depends on the fractal dimension of the medium as well as its walk dimension. (author)

  7. Samuel Taylor Coleridge’s

    Directory of Open Access Journals (Sweden)

    Aslı TEKİNAY

    2000-01-01

    Full Text Available There is a dark strain which can be traced in the poetry of all the major nineteenth century English romantic poets: a scepticism about the ultimate purpose of man's life, a sense of having lost a metaphysical certainty and faith in the presence of a benevolent power who maintains harmony and order in the universe. Samuel Taylor Coleridge is one of them. In "The Rime of the Ancient Mariner" and "Christabel", he reveals a nightmarish vision of the universe where moral order seems to be replaced by a cosmic "hap".

  8. A depositional model for the Taylor coal bed, Martin and Johnson counties, eastern Kentucky

    Science.gov (United States)

    Andrews, W.M.; Hower, J.C.; Ferm, J.C.; Evans, S.D.; Sirek, N.S.; Warrell, M.; Eble, C.F.

    1996-01-01

    This study investigated the Taylor coal bed in Johnson and Martin counties, eastern Kentucky, using field and petrographic techniques to develop a depositional model of the coal bed. Petrography and chemistry of the coal bed were examined. Multiple benches of the Taylor coal bed were correlated over a 10 km distance. Three sites were studied in detail. The coal at the western and eastern sites were relatively thin and split by thick clastic partings. The coal at the central site was the thickest and unsplit. Two major clastic partings are included in the coal bed. Each represents a separate and distinct fluvial splay. The Taylor is interpreted to have developed on a coastal plain with periodic flooding from nearby, structurally-controlled fluvial systems. Doming is unlikely due to the petrographic and chemical trends, which are inconsistent with modern Indonesian models. The depositional history and structural and stratigraphic setting suggest contemporaneous structural influence on thickness and quality of the Taylor coal bed in this area.

  9. Cryovolcanic Emplacement of Domes on Europa

    Science.gov (United States)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Stephen M.

    2016-01-01

    Here we explore the hypothesis that certain domes on Europa may have been produced by the extrusion of viscous cryolavas. A new mathematical method for the emplacement and relaxation of viscous lava domes is presented and applied to putative cryovolcanic domes on Europa. A similarity solution approach is applied to the governing equation for fluid flow in a cylindrical geometry, and dome relaxation is explored assuming a volume of cryolava has been rapidly emplaced onto the surface. Nonphysical sin- gularities inherent in previous models for dome relaxation have been eliminated, and cryolava cooling is represented by a time-variable viscosity. We find that at the onset of relaxation, bulk kinematic viscosities may lie in the range between 10(exp 3) and 10(exp 6) sq m/s, while the actual fluid lava viscosity may be much lower. Plausible relaxation times to form the domes, which are linked to bulk cryolava rheology, are found to range from 3.6 days to 7.5 years. We find that cooling of the cryolava, while dominated by conduction through an icy skin, should not prevent fluids from advancing and relaxing to form domes within the timescales considered. Determining the range of emplacement conditions for putative cryolava domes will shed light on Europa's resurfacing history. In addition, the rheologies and compositions of erupted cryolavas have implications for subsurface cryomagma ascent and local surface stress conditions on Europa.

  10. Environmental assessment: Richton Dome site, Mississippi

    International Nuclear Information System (INIS)

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Richton Dome site in Mississippi as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Richton Dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EAs. The site is in the Gulf interior region, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains two other potentially acceptable sites--the Cypress Creek Dome site in Mississippi and the Vacherie Dome site in Louisiana. Although the Cypress Creek Dome and the Vacherie Dome sites are suitable for site characterization, the DOE has concluded that the Richton Dome site is the preferred site in the Gulf interior region. On the basis of the evaluations reported in this EA, the DOE has found that the Richton Dome site is not disqualified under the guidelines

  11. Environmental assessment: Richton Dome Site, Mississippi

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Richton Dome site in Mississippi as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Richton Dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EAs. The site is in the Gulf interior region, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains two other potentially acceptable sites--the Cypress Creek Dome site in Mississippi and the Vacherie Dome site in Louisiana. Although the Cypress Creek Dome and the Vacherie Dome sites are suitable for site characterization, the DOE has concluded that the Richton Dome site is the preferred site in the Gulf interior region. On the basis of the evaluations reported in this EA, the DOE has found that the Richton Dome site is not disqualified under the guidelines.

  12. Environmental assessment: Richton Dome site, Mississippi

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Richton Dome site in Mississippi as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Richton Dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EAs. The site is in the Gulf interior region, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains two other potentially acceptable sites--the Cypress Creek Dome site in Mississippi and the Vacherie Dome site in Louisiana. Although the Cypress Creek Dome and the Vacherie Dome sites are suitable for site characterization, the DOE has concluded that the Richton Dome site is the preferred site in the Gulf interior region. On the basis of the evaluations reported in this EA, the DOE has found that the Richton Dome site is not disqualified under the guidelines.

  13. Environmental assessment: Richton Dome Site, Mississippi

    International Nuclear Information System (INIS)

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Richton Dome site in Mississippi as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Richton Dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EAs. The site is in the Gulf interior region, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains two other potentially acceptable sites--the Cypress Creek Dome site in Mississippi and the Vacherie Dome site in Louisiana. Although the Cypress Creek Dome and the Vacherie Dome sites are suitable for site characterization, the DOE has concluded that the Richton Dome site is the preferred site in the Gulf interior region. On the basis of the evaluations reported in this EA, the DOE has found that the Richton Dome site is not disqualified under the guidelines

  14. 33 CFR 117.335 - Taylor Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Taylor Creek. 117.335 Section 117.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.335 Taylor Creek. The draw of US441 bridge, mile 0...

  15. Taylorism and the Logic of Learning Outcomes

    Science.gov (United States)

    Stoller, Aaron

    2015-01-01

    This essay examines the shared philosophical foundations of Fredrick W. Taylor's scientific management principles and the contemporary learning outcomes movement (LOM). It analyses the shared philosophical ground between the focal point of Taylor's system--"the task"--and the conceptualization and deployment of "learning…

  16. 33 CFR 117.987 - Taylor Bayou.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Taylor Bayou. 117.987 Section 117.987 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Texas § 117.987 Taylor Bayou. The draws of the Union Pacific...

  17. Taylor instability in rhyolite lava flows

    Science.gov (United States)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  18. RADIATIVE RAYLEIGH-TAYLOR INSTABILITIES

    International Nuclear Information System (INIS)

    Jacquet, Emmanuel; Krumholz, Mark R.

    2011-01-01

    We perform analytic linear stability analyses of an interface separating two stratified media threaded by a radiation flux, a configuration relevant in several astrophysical contexts. We develop a general framework for analyzing such systems and obtain exact stability conditions in several limiting cases. In the optically thin, isothermal regime, where the discontinuity is chemical in nature (e.g., at the boundary of a radiation pressure-driven H II region), radiation acts as part of an effective gravitational field, and instability arises if the effective gravity per unit volume toward the interface overcomes that away from it. In the optically thick a diabaticregime where the total (gas plus radiation) specific entropy of a Lagrangian fluid element is conserved, for example at the edge of radiation pressure-driven bubble around a young massive star, we show that radiation acts like a modified equation of state and derive a generalized version of the classical Rayleigh-Taylor stability condition.

  19. Taylorism given a helping hand

    DEFF Research Database (Denmark)

    Tolsby, June

    2000-01-01

    of the IT system was perceived by some of the employees. Shows how, instead of increasing employees' work engagement, the IT system had the opposite effect. Demonstrates that the new It system contributed to a deskilling of the employees, to a more task-oriented approach to their work, and to increased employees......Illustrates how th implementation of a major information technology (IT) system within the Norwegian Army affected the way the employees perceived their flexibility and personal involvement in their work. By employing Taylor's initial works, this paper illustrates how the introduction......' interdependence. Instead of increasing employees' personal flexibility and involvement in their jobs, the research shows how the new IT system in fact contributed to a reduction in the freedom to choose when and how quickly to do their jobs....

  20. Re-assessment of recent (2008–2013 surface mass balance over Dome Argus, Antarctica

    Directory of Open Access Journals (Sweden)

    Minghu Ding

    2016-04-01

    Full Text Available At Dome Argus, East Antarctica, the surface mass balance (SMB from 2008 to 2013 was evaluated using 49 stakes installed across a 30×30 km area. Spatial analysis showed that at least 12 and 20 stakes are needed to obtain reliable estimates of SMB at local scales (a few hundred square metres and regional scales (tens of square kilometres, respectively. The estimated annual mean SMB was 22.9±5.9 kg m−2 yr−1, including a net loss by sublimation of −2.22±0.02 kg m−2 yr−1 and a mass gain by deposition of 1.37±0.01 kg m−2 yr−1. Therefore, ca. 14.3% of precipitation was modified after deposition, which should be considered when interpreting snow or ice core records produced by future drilling projects. The surface snow density and SMB in the western portion of Dome Argus are higher than in other areas, and these differences are likely related to the katabatic wind, which is strengthened by topography in this sector. A new digital elevation model (DEM of Dome Argus was generated, confirming that both peaks of the dome can be considered as the summit of the East Antarctic Ice Sheet. Findings from this study should be valuable for validating SMB estimates obtained from regional climate models and DEMs established using remote-sensing data.

  1. The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

    International Nuclear Information System (INIS)

    Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

    2013-01-01

    Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

  2. Arc jet testing of a Dynasil dome

    Science.gov (United States)

    Burrell, Jack O.; Strobel, Forrest A.

    1999-07-01

    Arc jet testing of the Hera modified ballistic reentry vehicle - 1E (MBRV-1E) nosetip was conducted in June of 1998. The tests were conducted in the Air Force's Arnold Engineering Development Center HEAT-H1 arc plasma test facility in Tullahoma, Tennessee. The MBRV-1 vehicle is a separating short- to medium-range target. The MBRV-1E nosetip incorporates a custom designed quartz dome that is integrated into the nosetip stagnation region. The dome was bonded to the baseline nosetip material, a well characterized carbon-carbon composite material, using a silica based ceramic bond materials. The objectives of the test were to demonstrate the thermal performance and structural integrity of the nosetip design by exposing tip to arc plasma-heated flow simulating the reentry flight environment. Pre-test analysis of the Dynasil dome performed using finite element analysis predicted the dome would survive the test conditions with no failures. Post-test inspection of the dome revealed a hard, opaque coating on the outer surface of the dome. Once removed, the dome was shown to have numerous surface cracks near the stagnation region. In addition to the surface cracks, significant pitting on the surface was observed through both an optical microscope and a scanning electron microscope. Post-test analyses were performed to determine the cause of these surface cracks. It was concluded that the cracks occurred during cooldown, and were a result of significant strength degradation which was caused by the surface pitting.

  3. Autonomous Dome for a Robotic Telescope

    Science.gov (United States)

    Kumar, A.; Sengupta, A.; Ganesh, S.

    2016-12-01

    The Physical Research Laboratory operates a 50 cm robotic observatory at Mount Abu (Rajsthan, India). This Automated Telescope for Variability Studies (ATVS) makes use of the Remote Telescope System 2 (RTS2) for autonomous operations. The observatory uses a 3.5 m dome from Sirius Observatories. We have developed electronics using Arduino electronic circuit boards with home grown logic and software to control the dome operations. We are in the process of completing the drivers to link our Arduino based dome controller with RTS2. This document is a short description of the various phases of the development and their integration to achieve the required objective.

  4. Pressure Dome for High-Pressure Electrolyzer

    Science.gov (United States)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

  5. Testing and data reduction of the Chinese Small Telescope Array (CSTAR) for Dome A, Antarctica

    International Nuclear Information System (INIS)

    Zhou Xu; Wu Zhenyu; Jiang Zhaoji; Hu Jingyao; Li Qisheng; Ma Jun; Wang Jiali; Wu Jianghua; Yan Jun; Cui Xiangqun; Gong Xuefei; Liu Genrong; Xia Lirong; Yuan Xiangyan; Zhai Fengxiang; Zhang Ru; Feng Longlong; Wang Lifan; Zhu Zhenxi

    2010-01-01

    The Chinese Small Telescope Array (CSTAR) is the first Chinese astronomical instrument on the Antarctic ice cap. The low temperature and low pressure testing of the data acquisition system was carried out in a laboratory refrigerator and on the 4500 m Pamirs high plateau, respectively. The results from the final four nights of test observations demonstrated that CSTAR was ready for operation at Dome A, Antarctica. In this paper, we present a description of CSTAR and the performance derived from the test observations.

  6. Environmental assessment overview: Richton Dome site, Mississippi

    International Nuclear Information System (INIS)

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified the Richton Dome site in Mississippi as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Richton Dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. The site is in the Gulf interior region, which is one of five distinct geohydrologic settings considered for the first repository. On the basis of the evaluations reported in this EA, the DOE has found that the Richton Dome site is not disqualified under the guidelines. On the basis of these findings, the DOE is nominating the Richton Dome site as one of five sites suitable for characterization. 3 figs

  7. Topical reports on Louisiana salt domes

    International Nuclear Information System (INIS)

    1983-09-01

    The Institute for Environmental Studies at Louisiana State University conducted research into the potential use of Louisiana salt domes for disposal of nuclear waste material. Topical reports generated in 1981 and 1982 related to Vacherie and Rayburn's domes are compiled and presented, which address palynological studies, tiltmeter monitoring, precise releveling, saline springs, and surface hydrology. The latter two are basically a compilation of references related to these topics. Individual reports are abstracted

  8. Taylor impact of glass rods

    International Nuclear Information System (INIS)

    Willmott, G.R.; Radford, D.D.

    2005-01-01

    The deformation and fracture behavior of soda-lime and borosilicate glass rods was examined during classic and symmetric Taylor impact experiments for impact pressures to 4 and 10 GPa, respectively. High-speed photography and piezoresistive gauges were used to measure the failure front velocities in both glasses, and for impact pressures below ∼2 GPa the failure front velocity increases rapidly with increasing pressure. As the pressure was increased above ∼3 GPa, the failure front velocities asymptotically approached maximum values between the longitudinal and shear wave velocities of each material; at ∼4 GPa, the average failure front velocities were 4.7±0.5 and 4.6±0.5 mm μs -1 for the soda-lime and borosilicate specimens, respectively. The observed mechanism of failure in these experiments involved continuous pressure-dependent nucleation and growth of microcracks behind the incident wave. As the impact pressure was increased, there was a decrease in the time to failure. The density of cracks within the failed region was material dependent, with the more open-structured borosilicate glass showing a larger fracture density

  9. Geothermal studies of seven interior salt domes

    International Nuclear Information System (INIS)

    1983-06-01

    This report defines and compares the geothermal environments of eight selected Gulf Coast salt domes. The thermal regimes in and around Gulf Coast salt domes are not well documented. The data base used for this study is an accumulation of bottom-hole temperature readings from oil and gas exploration wells and temperature logs run for the National Waste Terminal Storage (NWTS) program. The bottom-hole tempreatures were corrected in order to estimate the actual geothermal environments. Prior thermal studies and models indicate temperatures in and around salt domes are elevated above the norm by 1 0 F to 25 0 F. Using existing geothermal data and accepted theory, geothermal gradients for the selected domes and surrounding sediments were estimated. This study concludes that salt domes within a given basin have similar geothermal gradients, but that the basins differ in average geothermal gradients. This relationship is probably controlled by deep basement structural trends. No evidence of residual heat of emplacement was found associated with any of the selected domes

  10. Dynamics of helicity transport and Taylor relaxation

    International Nuclear Information System (INIS)

    Diamond, P.H.; Malkov, M.

    2003-01-01

    A simple model of the dynamics of Taylor relaxation is derived using symmetry principles alone. No statistical closure approximations are invoked or detailed plasma model properties assumed. Notably, the model predicts several classes of nondiffusive helicity transport phenomena, including traveling nonlinear waves and superdiffusive turbulent pulses. A universal expression for the scaling of the effective magnetic Reynolds number of a system undergoing Taylor relaxation is derived. Some basic properties of intermittency in helicity transport are examined

  11. Non-Taylor magnetohydrodynamic self-organization

    International Nuclear Information System (INIS)

    Zhu, Shao-ping; Horiuchi, Ritoku; Sato, Tetsuya.

    1994-10-01

    A self-organization process in a plasma with a finite pressure is investigated by means of a three-dimensional magnetohydrodynamic simulation. It is demonstrated that a non-Taylor finite β self-organized state is realized in which a perpendicular component of the electric current is generated and the force-free(parallel) current decreases until they reach to almost the same level. The self-organized state is described by an MHD force-balance relation, namely, j perpendicular = B x ∇p/B·B and j parallel = μB where μ is not a constant, and the pressure structure resembles the structure of the toroidal magnetic field intensity. Unless an anomalous perpendicular thermal conduction arises, the plasma cannot relax to a Taylor state but to a non-Taylor (non-force-free) self-organized state. This state becomes more prominent for a weaker resistivity condition. The non-Taylor state has a rather universal property, for example, independence of the initial β value. Another remarkable finding is that the Taylor's conjecture of helicity conservation is, in a strict sense, not valid. The helicity dissipation occurs and its rate slows down critically in accordance with the stepwise relaxation of the magnetic energy. It is confirmed that the driven magnetic reconnection caused by the nonlinearly excited plasma kink flows plays the leading role in all of these key features of the non-Taylor self-organization. (author)

  12. Rayleigh-Taylor mixing in supernova experiments

    International Nuclear Information System (INIS)

    Swisher, N. C.; Abarzhi, S. I.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.

    2015-01-01

    We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order

  13. Geohydrolic studies of Gulf Coast interior salt domes

    International Nuclear Information System (INIS)

    Smith, C.G. Jr.

    1977-01-01

    Disposal of high-level radioactive wastes in Gulf Coast salt domes requires that the cavities be free from groundwater dissolution for 250,000 years. Salinity variations of groundwater near selected domes were investigated. Saline groundwater anomalies (saline plumes) in aquifers pierced or uplifted by the dome may be the result of salt solution by groundwater. In the Northeast Texas salt dome basin electric logs of oil and gas wells have been used to estimate groundwater salinities in aquifers near selected domes. Thus far, the analyses have revealed saline groundwater anomalies around 4 of the 9 domes studied. Estimates of the rate of salt dissolution from domes associated with saline groundwater plumes indicate that less than 30 meters of salt will be removed from the upper surfaces of the dome in 250,000 years. Thus, these preliminary studies show that even apparently unstable domes may be sufficiently stable to serve as waste disposal sites. 6 figures

  14. 76 FR 76689 - Cibola National Forest, Mount Taylor Ranger District, NM, Mount Taylor Combined Exploratory Drilling

    Science.gov (United States)

    2011-12-08

    ... National Forest, Mount Taylor Ranger District, NM, Mount Taylor Combined Exploratory Drilling AGENCY... proposed action is to approve two Plans of Operations for exploratory uranium drilling on the Cibola... San Mateo. In total, there are up to 279 drill holes that would be drilled over a period not to exceed...

  15. Ice Sheets & Ice Cores

    DEFF Research Database (Denmark)

    Mikkelsen, Troels Bøgeholm

    Since the discovery of the Ice Ages it has been evident that Earth’s climate is liable to undergo dramatic changes. The previous climatic period known as the Last Glacial saw large oscillations in the extent of ice sheets covering the Northern hemisphere. Understanding these oscillations known....... The first part concerns time series analysis of ice core data obtained from the Greenland Ice Sheet. We analyze parts of the time series where DO-events occur using the so-called transfer operator and compare the results with time series from a simple model capable of switching by either undergoing...

  16. Status of Gulf Coast salt dome characterization

    International Nuclear Information System (INIS)

    Swanson, O.E.; Gibbons, M.G.; Deyling, M.A.; McPherson, R.B.

    1982-01-01

    Screening and characterization for a potential nuclear waste repository have progressed through the area phase in these Gulf Coast Salt Basins. The domes studied during the area phase are described briefly. The area characterization studies are outlined, and the resulting reports are listed. Geologic and environmental studies resulted in elimination of four domes from further consideration. The remaining domes were judged acceptable and were classified as to their favorability to license. Site characterization planning for location phase activities deals primarily with technical, environmental, and socioeconomic issues of concern to the states and/or to the Office of Nuclear Waste Isolation (ONWI), Department of Energy (DOE). These issues are listed and discussed. 16 references, 9 figures

  17. The research of suspen-dome structure

    Science.gov (United States)

    Gong, Shengyuan

    2017-09-01

    After overcoming the shortcomings of single-layer latticed shell and cable dome structure, the suspen-dome was developed by inheriting the advantages of them, and it was recognized and applied as a new type of prestressed force large span space structure. Based on the analysis of the background and mechanical principle, the researches of suspen-dome are reviewed, including form-finding analysis, the analysis of static force and stability, the dynamic behaviors and the earthquake resistant behavior, the analysis of prestressing force and optimization design, and the research status of the design of the fir-resistant performance etc. This thesis summarizes the methods of various researches, being a reference for further structural performance research and structural engineering application.

  18. Environmental assessment, Richton Dome site, Mississippi (US)

    Energy Technology Data Exchange (ETDEWEB)

    none,

    1986-05-01

    The Nuclear Waste Policy Act of 1982 (42 USC Sections 10101-10226) requires the environmental assessment of a potential site to include a statement of the basis for the nomination of a site as suitable for characterization. Volume 2 of this environmental assessment provides a detailed evaluation of the Richton Dome Site and its suitability as the site for a radioactive waste disposal facility under DOE siting guidelines, as well as a comparison of the Richton Dome site with other proposed sites. Evaluation of the Richton Dome site is based on the reference repository design, but the evaluation will not change if based on the Mission Plan repository concept. The comparative evaluation of proposed sites is required under DOE guidelines, but is not intended to directly support the subsequent recommendation of three sites for characterization as candidate sites. 428 refs., 24 figs., 62 tabs. (MHB)

  19. Environmental assessment, Richton Dome site, Mississippi

    International Nuclear Information System (INIS)

    1986-05-01

    The Nuclear Waste Policy Act of 1982 (42 USC Sections 10101-10226) requires the environmental assessment of a potential site to include a statement of the basis for the nomination of a site as suitable for characterization. Volume 2 of this environmental assessment provides a detailed evaluation of the Richton Dome Site and its suitability as the site for a radioactive waste disposal facility under DOE siting guidelines, as well as a comparison of the Richton Dome site with other proposed sites. Evaluation of the Richton Dome site is based on the reference repository design, but the evaluation will not change if based on the Mission Plan repository concept. The comparative evaluation of proposed sites is required under DOE guidelines, but is not intended to directly support the subsequent recommendation of three sites for characterization as candidate sites. 428 refs., 24 figs., 62 tabs

  20. Interpreting last glacial to Holocene dust changes at Talos Dome (East Antarctica: implications for atmospheric variations from regional to hemispheric scales

    Directory of Open Access Journals (Sweden)

    S. Albani

    2012-04-01

    Full Text Available Central East Antarctic ice cores preserve stratigraphic records of mineral dust originating from remote sources in the Southern Hemisphere, and represent useful indicators of climatic variations on glacial-interglacial time scales. The peripheries of the East Antarctic Ice Sheet, where ice-free areas with the potential to emit dust exist, have been less explored from this point of view. Here, we present a new profile of dust deposition flux and grain size distributions from an ice core drilled at Talos Dome (TALDICE, Northern Victoria Land, East Antarctica, where there is a significant input of dust from proximal Antarctic ice-free areas. We analyze dust and stable water isotopes variations from the Last Glacial Maximum to the Late Holocene, and compare them to the EPICA Dome C profiles from central East Antarctica. The smaller glacial-interglacial variations at Talos Dome compared to Dome C and a distinctive decreasing trend during the Holocene characterize the TALDICE dust profile. By deciphering the composite dust signal from both remote and local sources, we show the potential of this combined proxy of source activity and atmospheric transport to give information on both regional and larger spatial scales. In particular, we show how a regional signal, which we relate to the deglaciation history of the Ross Sea embayment, can be superimposed to the broader scale glacial-interglacial variability that characterizes other Antarctic sites.

  1. Near-dome geologic findings - Richton Dome, Mississippi: annual status report for FY 83

    International Nuclear Information System (INIS)

    1984-10-01

    Basin Analysis is a study of the regional and local stratigraphic, tectonic, and salt-tectonic conditions that influenced the development of the Mississippi Salt Basin and Richton Dome, an element within that basin. During FY 83, work was concentrated on the local area surrounding Richton Dome and included the writing of the Midyear FY 83 Richton Dome Screening and Suitability Review, input to the Site Characterization Plan that is being prepared by the Southern Region Geologic Project Manager, and initial development of a near-dome geologic model. The geologic model was compiled using information from approximately 300 oil and gas well geophysical logs and 128 line km (80 line mi) of seismic-reflection profiles. In addition to analysis and interpretation of the logs and profiles, stratigraphic data from each were assembled in a computer-based file and were used to produce computer-generated structural contour maps. Major findings from the analyses include a new configuration for the northern end of Richton Dome and improved definitions of near-dome faults and the rim syncline on the northern and eastern flanks of Richton Dome. 4 references, 6 figures

  2. Radiation observation at Dome Fuji Station, Antarctica

    Directory of Open Access Journals (Sweden)

    Naohiko Hirasawa

    2008-06-01

    Full Text Available This paper reports radiation observations at Dome Fuji Station from February 1, 2003 to January 20, 2004, carried out by the 44th Japanese Antarctic Research Expedition team. The radiometers which measured the upward longwave radiation (LWu, the downward longwave (LWd and the downward shortwave (SWd were equipped with fans to avoid frosting on the surface of the radiometer dome by air circulation. The upward shortwave radiation (SWu measured by a radiometer without fan needs correction, which we leave as a problem for the future. In addition, as for LWd and LWu in the polar night, a typical radiational cooling case and a suppressed radiational cooling one are shown.

  3. A spherical Taylor-Couette dynamo

    Science.gov (United States)

    Marcotte, Florence; Gissinger, Christophe

    2016-04-01

    We present a new scenario for magnetic field amplification in the planetary interiors where an electrically conducting fluid is confined in a differentially rotating, spherical shell (spherical Couette flow) with thin aspect-ratio. When the angular momentum sufficiently decreases outwards, a primary hydrodynamic instability is widely known to develop in the equatorial region, characterized by pairs of counter-rotating, axisymmetric toroidal vortices (Taylor vortices) similar to those observed in cylindrical Couette flow. We characterize the subcritical dynamo bifurcation due to this spherical Taylor-Couette flow and study its evolution as the flow successively breaks into wavy and turbulent Taylor vortices for increasing Reynolds number. We show that the critical magnetic Reynolds number seems to reach a constant value as the Reynolds number is gradually increased. The role of global rotation on the dynamo threshold and the implications for planetary interiors are finally discussed.

  4. Characteristics and mode of emplacement of gneiss domes and plutonic domes in central-eastern Pyrenees

    Science.gov (United States)

    Soula, Jean-Claude

    Gneiss domes and plutonic granitoid domes make up almost 50% of the pre-Hercynian terrains in the Central and Eastern Pyrenees. From a structural study of the shape and internal structure of the domes and of their relationships with the enclosing rocks, it can be shown that both types of domes were emplaced diapirically during the major regional deformation phase and the peak of regional metamorphism. The study also shows that the internal structure, the overall shape and general behaviour relative to the host rocks are similar for plutonic domes and for gneiss domes. This appears to be in good agreement with H. Ramberg's (1967, Gravity Deformation and the Earth's Crust. Academic Press, London; 1970, Model studies in relation to intrusion of plutonic bodies. In: Mechanisms of Igneous Intrusion (edited by Newall, G. & Rast, N.) Geol. J. Spec. Issue2, 261-286.) model studies showing that dome or mushroom-like structures, similar to those observed, develop when there is a small viscosity ratio between the rising body and its enclosing medium. This implies a high crystal content for the granitoid magma. This crystal content has been estimated by (i) calculating the viscosity and density in natural conditions from petrological data for the magma considered as a suspension, using the model and program of J. P. Carron et al. (1978 Bull Soc. géol. Fr.20, 739-744.); (ii) using the recent results of experimental deformation of partially melted granites of I. van der Molen & M. S. Paterson (1979, Contr. Miner. Petrol.70, 299-318.) and (ii) comparing the preceding results with the data obtained by deformation experiments on rocks similar to those enclosing the domes. The minimum crystal content for the development of a dome-like structure has been, thus, estimated to about 70%, i.e. a value very close to that estimated by van der Molen & Paterson (1979) to be the critical value separating the granular framework flow from suspension-like behaviour. The effect of small

  5. Ice, Ice, Baby!

    Science.gov (United States)

    Hamilton, C.

    2008-12-01

    The Center for Remote Sensing of Ice Sheets (CReSIS) has developed an outreach program based on hands-on activities called "Ice, Ice, Baby". These lessons are designed to teach the science principles of displacement, forces of motion, density, and states of matter. These properties are easily taught through the interesting topics of glaciers, icebergs, and sea level rise in K-8 classrooms. The activities are fun, engaging, and simple enough to be used at science fairs and family science nights. Students who have participated in "Ice, Ice, Baby" have successfully taught these to adults and students at informal events. The lessons are based on education standards which are available on our website www.cresis.ku.edu. This presentation will provide information on the activities, survey results from teachers who have used the material, and other suggested material that can be used before and after the activities.

  6. “What” is Frederick Winslow Taylor

    OpenAIRE

    Andrej Markovic

    2006-01-01

    Raising the issue of Taylor and his scientific management after less than a hundred years seems at first glance to be quite anachronistic. Today we are more likely to find Taylor’s works in antique shops than in the libraries of the schools of management. Has the memory of utilitarian and pragmatic managerial knowledge of a century back faded, or are we in a way ashamed of Taylor, the protagononist of management? How does the research into the origin and nature of management affect the effici...

  7. Towards finite density QCD with Taylor expansions

    International Nuclear Information System (INIS)

    Karsch, F.; Schaefer, B.-J.; Wagner, M.; Wambach, J.

    2011-01-01

    Convergence properties of Taylor expansions of observables, which are also used in lattice QCD calculations at non-zero chemical potential, are analyzed in an effective N f =2+1 flavor Polyakov quark-meson model. A recently developed algorithmic technique allows the calculation of higher-order Taylor expansion coefficients in functional approaches. This novel technique is for the first time applied to an effective N f =2+1 flavor Polyakov quark-meson model and the findings are compared with the full model solution at finite densities. The results are used to discuss prospects for locating the QCD phase boundary and a possible critical endpoint in the phase diagram.

  8. Optimised intake stroke analysis for flat and dome head pistons ...

    African Journals Online (AJOL)

    Optimised intake stroke analysis for flat and dome head pistons. ... in understanding the performance characteristics optioned between flat head and dome head pistons in engine design. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  9. Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr

    Science.gov (United States)

    Cavitte, Marie G. P.; Parrenin, Frédéric; Ritz, Catherine; Young, Duncan A.; Van Liefferinge, Brice; Blankenship, Donald D.; Frezzotti, Massimo; Roberts, Jason L.

    2018-04-01

    We reconstruct the pattern of surface accumulation in the region around Dome C, East Antarctica, since the last glacial. We use a set of 18 isochrones spanning all observable depths of the ice column, interpreted from various ice-penetrating radar surveys and a 1-D ice flow model to invert for accumulation rates in the region. The shallowest four isochrones are then used to calculate paleoaccumulation rates between isochrone pairs using a 1-D assumption where horizontal advection is negligible in the time interval of each layer. We observe that the large-scale (100s km) surface accumulation gradient is spatially stable through the last 73 kyr, which reflects current modeled and observed precipitation gradients in the region. We also observe small-scale (10 s km) accumulation variations linked to snow redistribution at the surface, due to changes in its slope and curvature in the prevailing wind direction that remain spatially stationary since the last glacial.

  10. Drilling comparison in "warm ice" and drill design comparison

    DEFF Research Database (Denmark)

    Augustin, L.; Motoyama, H.; Wilhelms, F.

    2007-01-01

    For the deep ice-core drilling community, the 2005/06 Antarctic season was an exciting and fruitful one. In three different Antarctic locations, Dome Fuji, EPICA DML and Vostok, deep drillings approached bedrock (the ice-water interface in the case of Vostok), emulating what had previously been...... achieved at NorthGRIP, Greenland, (summer 2003 and 2004) and at EPICA Dome C2, Antarctica (season 2004/05). For the first time in ice-core drilling history, three different types of drill (KEMS, JARE and EPICA) simultaneously reached the depth of 'warm ice' under high pressure. After excellent progress...... at each site, the drilling rate dropped and the drilling teams had to deal with refrozen ice on cutters and drill heads. Drills have different limits and perform differently. In this comparative study, we examine depth, pressure, temperature, pump flow and cutting speed. Finally, we compare a few...

  11. Borehole locations on seven interior salt domes

    International Nuclear Information System (INIS)

    Simcox, A.C.; Wampler, S.L.

    1982-08-01

    This report is designed as an inventory of all wells known to have been drilled within a five-mile radius of each of seven salt domes within the Interior Salt Basin in east Texas, northern Louisiana and Mississippi. There are 72 boreholes that entered salt above an elevation of -3000 feet mean sea level. For these, details of location, drilling dates, depth of casing and cement, elevation of top of caprock and salt, etc., are given on tables in the appendix. Of the seven domes, Oakwood has the largest number of boreholes, thirty-eight (including two sidetracked wells) that enter the salt stock above -3000 feet mean sea level; another dome in northeast Texas, Keechi, has eight; in northern Louisiana, Rayburn's has four and Vacherie has five; in southern Mississippi, Cypress Creek has seven, Lampton has one, and Richton has nine. In addition, all wells known outside the supra-domal area, but within a five-mile radius of the center of the 7 domes are separately catalogued

  12. Experiments in connection with Salt Domes

    NARCIS (Netherlands)

    Escher, B.G.; Kuenen, Ph.H.

    1928-01-01

    The different theories concerning the origin of Salt Domes in Roumania, Germany, Texas, Louisiana, Colorado and Utah are discussed. In Roumania the salt occurs in cores of “Diapir” anticlines. The existance of hills of salt indicates, that the salt is still pushing upwards. In Germany the salt

  13. A Case Study of the Vredefort Dome

    African Journals Online (AJOL)

    South Africa became a signatory to and ratified the World Heritage Convention, 1972 (WHC) in 1997. It thereby voluntarily agreed to identify and conserve world heritage areas of universal value for the benefit of mankind. This article presents a case study of the Vredefort Dome, one of South Africa\\'s World Heritage Sites ...

  14. The use of aluminum dome tank roofs

    International Nuclear Information System (INIS)

    Morovich, G.L.

    1992-01-01

    Since the late 1970's the aluminum dome tank roof has gained wide usage for both new and retrofit applications. The increased application for the structure results from a need for maintenance reduction, environmental considerations, concern for product quality and economics. The American Petroleum Institute (API) has approved Standard API 650, Appendix G - Structurally Supported Aluminum Dome Roofs for publication. The aluminum dome was originally used as weather cover for retrofiting external floating roof tanks. The roof was considered for the reduction of maintenance related to draining water from the external floating roofs and problems resulting from freezing of drain lines and snow accumulation. This paper reports that environmental concerns have expanded the value of aluminum dome roofs. Rainwater bypassing the seals of an external floating roof became classified as a hazardous material requiring special and expensive disposal procedures. The marketing terminal facilities typically do not have the capacity for proper treatment of contaminated bottom water. With new fuel additives being water soluble, water contamination not only created a hazardous waste disposal problem, but resulted in reduced product quality

  15. The compression dome concept: the restorative implications.

    Science.gov (United States)

    Milicich, Graeme

    2017-01-01

    Evidence now supports the concept that the enamel on a tooth acts like a compression dome, much like the dome of a cathedral. With an overlying enamel compression dome, the underlying dentin is protected from damaging tensile forces. Disruption of a compression system leads to significant shifts in load pathways. The clinical restorative implications are significant and far-reaching. Cutting the wrong areas of a tooth exposes the underlying dentin to tensile forces that exceed natural design parameters. These forces lead to crack propagation, causing flexural pain and eventual fracture and loss of tooth structure. Improved understanding of the microanatomy of tooth structure and where it is safe to cut teeth has led to a revolution in dentistry that is known by several names, including microdentistry, minimally invasive dentistry, biomimetic dentistry, and bioemulation dentistry. These treatment concepts have developed due to a coalescence of principles of tooth microanatomy, material science, adhesive dentistry, and reinforcing techniques that, when applied together, will allow dentists to repair a compromised compression dome so that it more closely replicates the structure of the healthy tooth.

  16. The Senior Capstone, Dome or Spire?

    Science.gov (United States)

    Heinemann, Robert L.

    This paper examines a basic philosophical issue involved with the purpose of a senior capstone communication course required of all majors. The issue involves two opposites: closure, represented by the dome, and further exploration, represented by the spire. Both approaches have legitimate claims for a capstone course. There is definitely a need…

  17. Mechanical Design of Metal Dome for Industrial Application

    Science.gov (United States)

    Jin-Chee Liu, Thomas; Chen, Li-Wei; Lin, Nai-Pin

    2018-02-01

    In this paper, the mechanical design of metal domes is studied using finite element analysis. The snap-through behavior of a practical button design that uses a metal dome is found. In addition, the individual click ratio and maximum force for a variety of metal domes are determined. This paper provides guidance on button design for industrial engineers.

  18. Type 1 neovascularization with polypoidal lesions complicating dome shaped macula

    OpenAIRE

    Naysan, Jonathan; Dansingani, Kunal K; Balaratnasingam, Chandrakumar; Freund, K Bailey

    2015-01-01

    Dome-shaped macula is described as an inward bulge of the macula within a posterior staphyloma in highly myopic eyes. Choroidal neovascularization is a known complication that can cause visual loss in dome-shaped macula. Herein, we describe a patient who presented with features of polypoidal choroidal neovascularization that developed on a background of high myopia with dome-shaped macula.

  19. Constructions of legitimacy: the Charles Taylor trial

    NARCIS (Netherlands)

    Glasius, M.; Meijers, T.

    2012-01-01

    This article examines the discourses of the prosecution and the defence in the case of Charles Taylor before the Special Court for Sierra Leone. It contributes to current debates about the legitimacy and utility of international criminal justice, which have tended to neglect the examination of

  20. Neo-Taylorism in Educational Administration?

    Science.gov (United States)

    Gronn, Peter C.

    1982-01-01

    Reviews eight recent observational studies of school administrators and criticizes the studies' use of "time and motion" assumptions drawn from Frederick Winslow Taylor's ideas. Outlines an alternate approach based on "thick" description of administrators' work, including their talk, as exemplified in James Boswell's biography…

  1. Dominant Taylor Spectrum and Invariant Subspaces

    Czech Academy of Sciences Publication Activity Database

    Ambrozie, Calin-Grigore; Müller, Vladimír

    2009-01-01

    Roč. 61, č. 1 (2009), s. 101-111 ISSN 0379-4024 R&D Projects: GA ČR(CZ) GA201/06/0128 Institutional research plan: CEZ:AV0Z10190503 Keywords : Taylor spectrum * Scott-Brown technique * dominant spectrum Subject RIV: BA - General Mathematics Impact factor: 0.580, year: 2009

  2. Wall Shear Rates in Taylor Vortex Flow

    Czech Academy of Sciences Publication Activity Database

    Sobolík, V.; Jirout, T.; Havlica, Jaromír; Kristiawan, M.

    2011-01-01

    Roč. 4, č. 3 (2011), s. 25-31 ISSN 1735-3572 Grant - others:ANR:(FR) ANR-08-BLAN-0184-01 Institutional research plan: CEZ:AV0Z40720504 Keywords : taylor-couette flow * electrodiffusion diagnostics * membrane reactors Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.jafmonline.net/modules/journal/journal_browse.php?EJjid=13

  3. Transitions between Taylor vortices and spirals via wavy Taylor vortices and wavy spirals

    International Nuclear Information System (INIS)

    Hoffmann, Ch; Altmeyer, S; Pinter, A; Luecke, M

    2009-01-01

    We present numerical simulations of closed wavy Taylor vortices and of helicoidal wavy spirals in the Taylor-Couette system. These wavy structures appearing via a secondary bifurcation out of Taylor vortex flow and out of spiral vortex flow, respectively, mediate transitions between Taylor and spiral vortices and vice versa. Structure, dynamics, stability and bifurcation behaviour are investigated in quantitative detail as a function of Reynolds numbers and wave numbers for counter-rotating as well as corotating cylinders. These results are obtained by solving the Navier-Stokes equations subject to axial periodicity for a radius ratio η=0.5 with a combination of a finite differences method and a Galerkin method.

  4. 76 FR 18378 - Amendment of Class E Airspace; Taylor, AZ

    Science.gov (United States)

    2011-04-04

    ...-1189; Airspace Docket No. 10-AWP-19] Amendment of Class E Airspace; Taylor, AZ AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action will amend Class E airspace at Taylor Airport, Taylor, AZ, to accommodate aircraft using the CAMBO One Departure, and the Area Navigation (RNAV...

  5. The influence of the synoptic regime on stable water isotopes in precipitation at Dome C, East Antarctica

    Directory of Open Access Journals (Sweden)

    E. Schlosser

    2017-10-01

    Full Text Available The correct derivation of paleotemperatures from ice cores requires exact knowledge of all processes involved before and after the deposition of snow and the subsequent formation of ice. At the Antarctic deep ice core drilling site Dome C, a unique data set of daily precipitation amount, type, and stable water isotope ratios is available that enables us to study in detail atmospheric processes that influence the stable water isotope ratio of precipitation. Meteorological data from both automatic weather station and a mesoscale atmospheric model were used to investigate how different atmospheric flow patterns determine the precipitation parameters. A classification of synoptic situations that cause precipitation at Dome C was established and, together with back-trajectory calculations, was utilized to estimate moisture source areas. With the resulting source area conditions (wind speed, sea surface temperature, and relative humidity as input, the precipitation stable isotopic composition was modeled using the so-called Mixed Cloud Isotope Model (MCIM. The model generally underestimates the depletion of 18O in precipitation, which was not improved by using condensation temperature rather than inversion temperature. Contrary to the assumption widely used in ice core studies, a more northern moisture source does not necessarily mean stronger isotopic fractionation. This is due to the fact that snowfall events at Dome C are often associated with warm air advection due to amplification of planetary waves, which considerably increases the site temperature and thus reduces the temperature difference between source area and deposition site. In addition, no correlation was found between relative humidity at the moisture source and the deuterium excess in precipitation. The significant difference in the isotopic signal of hoarfrost and diamond dust was shown to disappear after removal of seasonality. This study confirms the results of an earlier study

  6. The influence of the synoptic regime on stable water isotopes in precipitation at Dome C, East Antarctica

    Science.gov (United States)

    Schlosser, Elisabeth; Dittmann, Anna; Stenni, Barbara; Powers, Jordan G.; Manning, Kevin W.; Masson-Delmotte, Valérie; Valt, Mauro; Cagnati, Anselmo; Grigioni, Paolo; Scarchilli, Claudio

    2017-10-01

    The correct derivation of paleotemperatures from ice cores requires exact knowledge of all processes involved before and after the deposition of snow and the subsequent formation of ice. At the Antarctic deep ice core drilling site Dome C, a unique data set of daily precipitation amount, type, and stable water isotope ratios is available that enables us to study in detail atmospheric processes that influence the stable water isotope ratio of precipitation. Meteorological data from both automatic weather station and a mesoscale atmospheric model were used to investigate how different atmospheric flow patterns determine the precipitation parameters. A classification of synoptic situations that cause precipitation at Dome C was established and, together with back-trajectory calculations, was utilized to estimate moisture source areas. With the resulting source area conditions (wind speed, sea surface temperature, and relative humidity) as input, the precipitation stable isotopic composition was modeled using the so-called Mixed Cloud Isotope Model (MCIM). The model generally underestimates the depletion of 18O in precipitation, which was not improved by using condensation temperature rather than inversion temperature. Contrary to the assumption widely used in ice core studies, a more northern moisture source does not necessarily mean stronger isotopic fractionation. This is due to the fact that snowfall events at Dome C are often associated with warm air advection due to amplification of planetary waves, which considerably increases the site temperature and thus reduces the temperature difference between source area and deposition site. In addition, no correlation was found between relative humidity at the moisture source and the deuterium excess in precipitation. The significant difference in the isotopic signal of hoarfrost and diamond dust was shown to disappear after removal of seasonality. This study confirms the results of an earlier study carried out at Dome

  7. Screening specifications for Gulf Coast salt domes

    International Nuclear Information System (INIS)

    Brunton, G.D.; Laughon, R.B.; McClain, W.C.

    1978-01-01

    A reconnaissance survey of the salt domes of Mississippi, Louisiana, and east Texas is being planned to identify study areas for potential sites for radioactive waste disposal. Preliminary screening specifications were derived for each of the geological evaluation criteria by application of the significant factors that will have an impact on the reconnaissance survey. The procedure for the derivation of each screening specification is discussed. The screening specifications are the official OWI values to be used for the first-cut acceptance for salt dome study areas along the Gulf Coast. The derivation of the screening specifications is illustrated by (1) a statement of the geological evaluation criterion, (2) a discussion of the pertinent factors affecting the criterion, and (3) the evaluation of the value of the specification

  8. consistencia en dome: un caso de estudio

    Directory of Open Access Journals (Sweden)

    DANIEL CABARCAS

    2006-01-01

    Full Text Available Las herramientas metaCASE ofrecen una funcionalidad similar a la de las herramientas CASE convencionales para notaciones gráficas arbitrarias, una vez estas notaciones le sean especificadas adecuadamente. La principal dificultad de dichas herramientas es la especificación de las diferentes reglas de consistencia, que deben tenerse en cuenta cuando se usa una notación. En este artículo se presenta la especificación de dos reglas de consistencia del diagrama de clases de UML en el metaCASE DOME, codificadas en el lenguaje de programación Alter. Adicionalmente, se hace un análisis comparativo entre las especificaciones de los aspectos estructurales y de las reglas de consistencia en DOME y en la especificación de UML provista por el OMG.

  9. Upheaval Dome, Utah, USA: Impact Origin Confirmed

    OpenAIRE

    Buchner, Elmar; Kenkmann, Thomas

    2008-01-01

    Upheaval Dome is a unique circular structure on the Colorado Plateau in SE Utah, the origin of which has been controversially discussed for decades. It has been interpreted as a crypto volcanic feature, a salt diapir, a pinched-off salt diapir, and an eroded impact crater. While recent structural mapping, modeling, and analyses of deformation mechanisms strongly support an impact origin, ultimate proof, namely the documentation of unambiguous shock features, has yet to be successfully provide...

  10. Functional Balance Training Using a Domed Device

    Science.gov (United States)

    2005-02-01

    people. Exerc. Sport Sci. Rev. 31:182–187. 2003. 17. Roubenoff, R. Sarcopenia and its im- plications for the elderly . Eur. J. Clin. Nutr. 54(Suppl 3):S40–7... elderly and the injured (7, 10, 18). Functional balance training involves skilled body movement patterns that si- multaneously require movement and...important aspect of athletic and occupational perfor- mance, in the elderly , and for injury rehabilitation, where use of a novel domed device can be

  11. Teapot Dome: past, present, and future

    Energy Technology Data Exchange (ETDEWEB)

    Curry, W.H. Jr.

    1977-05-01

    The Teapot Dome field is the 99th largest oil field in the United States with a proved reserve of 42,515,000 bbl, yet the field is sparsely drilled and underdeveloped. The writer credits Naval Petroleum Reserve No. 3 with 38 million bbl of future reserves. The long history of Teapot Dome since the early 1900s, sometimes turbulent, sometimes dormant, was marred by government scandal, akin to Watergate in notoriety, in the 1920s. Harry F. Sinclair's Mammoth Oil Company obtained leases from the Department of the Interior in a fraudulent manner which led to prison sentences for some of the principals. Oil production in the Teapot Dome field is from three formations; the shallow Shannon at depths of 400 to 1,000 ft (122 to 305 m); the Second Wall Creek member of the Frontier Formation at 2,500 to 3,000 ft (362 to 914 m); and the Tensleep Sandstone at 5,500 ft (1,676 m). The Second Wall Creek is the principal producing sandstone and has the greatest future production potential. Current production is small. As of December 1973, each of the 42 Navy wells averaged 4.4 b/d from the Shannon Sandstone, and 49 offset wells averaged 2.2 b/d each. In the Second Wall Creek, each of the 23 Navy wells averaged 10 b/d and 8 offset wells averaged 14.9 b/d each. Total daily production was 416 bbl and grand total for Teapot Dome through December 1975 was 7,762,709 bbl.

  12. MROI Array telescopes: the relocatable enclosure domes

    Science.gov (United States)

    Marchiori, G.; Busatta, A.; Payne, I.

    2016-07-01

    The MROI - Magdalena Ridge Interferometer is a project which comprises an array of up to 10 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. EIE GROUP Srl, Venice - Italy, was awarded the contract for the design, the construction and the erection on site of the MROI by the New Mexico Institute of Mining and Technology. The close-pack array of the MROI - including all 10 telescopes, several of which are at a relative distance of less than 8m center to center from each other - necessitated an original design for the Unit Telescope Enclosure (UTE). This innovative design enclosure incorporates a unique dome/observing aperture system to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). The main characteristics of this Relocatable Enclosure Dome are: a Light insulated Steel Structure with a dome made of composites materials (e.g. glass/carbon fibers, sandwich panels etc.), an aperture motorized system for observation, a series of louvers for ventilation, a series of electrical and plants installations and relevant auxiliary equipment. The first Enclosure Dome is now under construction and the completion of the mounting on site id envisaged by the end of 2016. The relocation system utilizes a modified reachstacker (a transporter used to handle freight containers) capable of maneuvering between and around the enclosures, capable of lifting the combined weight of the enclosure with the telescope (30tons), with minimal impacts due to vibrations.

  13. Underwater Calibration of Dome Port Pressure Housings

    Science.gov (United States)

    Nocerino, E.; Menna, F.; Fassi, F.; Remondino, F.

    2016-03-01

    Underwater photogrammetry using consumer grade photographic equipment can be feasible for different applications, e.g. archaeology, biology, industrial inspections, etc. The use of a camera underwater can be very different from its terrestrial use due to the optical phenomena involved. The presence of the water and camera pressure housing in front of the camera act as additional optical elements. Spherical dome ports are difficult to manufacture and consequently expensive but at the same time they are the most useful for underwater photogrammetry as they keep the main geometric characteristics of the lens unchanged. Nevertheless, the manufacturing and alignment of dome port pressure housing components can be the source of unexpected changes of radial and decentring distortion, source of systematic errors that can influence the final 3D measurements. The paper provides a brief introduction of underwater optical phenomena involved in underwater photography, then presents the main differences between flat and dome ports to finally discuss the effect of manufacturing on 3D measurements in two case studies.

  14. From Taylor to Drucker: Management and Managing

    OpenAIRE

    Primoz Turk

    2008-01-01

    The article discusses the question of management and managing, focusing on the changes which took place in the period from Taylor to Drucker. In this period two turning points dramatically changed the nature of management. Management which started within the organization was at first concerned with the organization’s inner workings. This concern with the organization’s ‘inside’ is gradually projected to the outside, to society as a whole. Simultaneously, changes occur in managing. Managing wh...

  15. Liquidity Trap and Stability of Taylor Rules

    OpenAIRE

    Le Riche , Antoine; Magris , Francesco; Parent , Antoine

    2016-01-01

    We study a productive economy with fractional cash-in-advance constraint on consumption expenditures. Government issues safe bonds and levies taxes to finance public expenditures, while the Central Bank follows a feedback Taylor rules by pegging the nominal interest rate. We show that when the nominal interest rate is bound to be non-negative, under active policy rules a Liquidity Trap steady state does emerge besides the Leeper (1991) equilibrium. The stability of the two steady states depen...

  16. A taylor series approach to survival analysis

    International Nuclear Information System (INIS)

    Brodsky, J.B.; Groer, P.G.

    1984-09-01

    A method of survival analysis using hazard functions is developed. The method uses the well known mathematical theory for Taylor Series. Hypothesis tests of the adequacy of many statistical models, including proportional hazards and linear and/or quadratic dose responses, are obtained. A partial analysis of leukemia mortality in the Life Span Study cohort is used as an example. Furthermore, a relatively robust estimation procedure for the proportional hazards model is proposed. (author)

  17. What factors control the superficial lava dome explosivity?

    Science.gov (United States)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoit; Morgan, Daniel J.

    2015-04-01

    Dome-forming eruption is a frequent eruptive style; lava domes result from intermittent, slow extrusion of viscous lava. Most dome-forming eruptions produce highly microcrystallized and highly- to almost totally-degassed magmas which have a low explosive potential. During lava dome growth, recurrent collapses of unstable parts are the main destructive process of the lava dome, generating concentrated pyroclastic density currents (C-PDC) channelized in valleys. These C-PDC have a high, but localized, damage potential that largely depends on the collapsed volume. Sometimes, a dilute ash cloud surge develops at the top of the concentrated flow with an increased destructive effect because it may overflow ridges and affect larger areas. In some cases, large lava dome collapses can induce a depressurization of the magma within the conduit, leading to vulcanian explosions. By contrast, violent, laterally directed, explosions may occur at the base of a growing lava dome: this activity generates dilute and turbulent, highly-destructive, pyroclastic density currents (D-PDC), with a high velocity and propagation poorly dependent on the topography. Numerous studies on lava dome behaviors exist, but the triggering of lava dome explosions is poorly understood. Here, seven dome-forming eruptions are investigated: in the Lesser Antilles arc: Montagne Pelée, Martinique (1902-1905, 1929-1932 and 650 y. BP eruptions), Soufrière Hills, Montserrat; in Guatemala, Santiaguito (1929 eruption); in La Chaîne des Puys, France (Puy de Dome and Puy Chopine eruptions). We propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by these key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite

  18. Centrifugally Driven Rayleigh-Taylor Instability

    Science.gov (United States)

    Scase, Matthew; Hill, Richard

    2017-11-01

    The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.

  19. Fluctuation scaling, Taylor's law, and crime.

    Directory of Open Access Journals (Sweden)

    Quentin S Hanley

    Full Text Available Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026 while burglary exhibited a greater exponent (α = 1.292 ± 0.029 indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs to 2.094 ± 0081 (Other Crimes. Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

  20. Fluctuation scaling, Taylor's law, and crime.

    Science.gov (United States)

    Hanley, Quentin S; Khatun, Suniya; Yosef, Amal; Dyer, Rachel-May

    2014-01-01

    Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026) while burglary exhibited a greater exponent (α = 1.292 ± 0.029) indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs) to 2.094 ± 0081 (Other Crimes). Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

  1. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling

    Science.gov (United States)

    Passalacqua, Olivier; Ritz, Catherine; Parrenin, Frédéric; Urbini, Stefano; Frezzotti, Massimo

    2017-09-01

    Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF), which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice-bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km × 130 km area, with a N-S gradient and with values ranging from 48 to 60 mW m-2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF.

  2. Outline of surface mass balance at Dome Fuji, East Antarctica, by the stake method from 1995 to 2006

    Directory of Open Access Journals (Sweden)

    Takao Kameda

    2008-06-01

    Full Text Available This paper describes observational results of surface mass balance (SMB at Dome Fuji (77°19'01″S, 39°42'11″E; 3810m a.s.l., East Antarctica from 1995 to 2006. The SMB was estimated using 36 bamboo stakes (grid of 6×6, placed at 20m intervals. The heights of the stake tops from the snow surface were measured at 0.5cm resolution twice monthly in 1995, 1996, 1997, and 2003, and once a year for the rest of the study period. The annual SMB from 1995 to 2006 at Dome Fuji was 27.3±1.5kgm^a^. This result agrees well with the annual SMB from AD 1260 to 1993 (26.4kgm^a^, estimated from volcanic signals in the Dome Fuji ice core. From 1995 to 2006, there were 37 incidences of negative or zero annual SMB, which was 8.6%. Compared with similar studies at Vostok, South Pole and Dome C, we found that a site with SMB over 190kgm^a^ is expected to have annual snow accumulation at the 95% confidence level. Sites from 1500 to 2500m above sea level fit the criteria on the Antarctic ice sheet. According to stake and snow pit observations at Vostok, we estimated that the probability of an annual layer missing (hiatus at Dome Fuji under present-day and glacial conditions are 9.4% and 11.4%, respectively. Variations of SMB measured by 36-stakes for 12 years were also analyzed.

  3. Evidence of calcium carbonates in coastal (Talos Dome and Ross Sea area) East Antarctica snow and firn: Environmental and climatic implications

    Science.gov (United States)

    Sala, M.; Delmonte, B.; Frezzotti, M.; Proposito, M.; Scarchilli, C.; Maggi, V.; Artioli, G.; Dapiaggi, M.; Marino, F.; Ricci, P. C.; De Giudici, G.

    2008-07-01

    Micrometre-sized aeolian dust particles stored in Antarctic firn and ice layers are a useful tool for reconstructing climate and environmental changes in the past. The mineral content, particle concentration and chemical composition of modern dust in firn cores from the peripherycal dome (Talos Dome) and coastal area of East Antarctica (Ross Sea sector) were investigated. During analyses there was a considerable decrease in microparticle concentrations within a few hours of ice sample melting, accompanied by a systematic increase in the concentration of calcium ions (Ca 2+) in solution. Based on mineralogical phase analyses, which reveal the presence of anhydrous and hydrous calcium carbonates such as calcite (CaCO 3), monohydrocalcite (CaCO 3·H 2O) and ikaite (CaCO 3·6H 2O, hexahydrate calcium carbonate), the observed variations in concentrations are ascribed to the partial dissolution of the carbonate content of samples. Soluble carbonate compounds are thus primary aerosols included into the samples along with insoluble aluminosilicate minerals. We hypothesize hydrous carbonates may derive from the sea ice surface, where ikaite typically forms at the early stages of sea ice formation. Back trajectory calculations show that favourable events for air mass advection from the sea ice surface to Talos Dome are rare but likely to occur.

  4. Geohydrology of the Keechi, Mount Sylvan, Oakwood, and Palestine salt domes in the northeast Texas salt-dome basin

    International Nuclear Information System (INIS)

    Carr, J.E.; Halasz, S.J.; Peters, H.B.

    1980-01-01

    The salt within these domes has penetrated as much as 20,000 feet of Mesozoic and Cenozoic strata, and presently extends to within 120 to 800 feet of the land surface. The salt penetrates or closely underlies major freshwater and salinewater aquifers within the basin. To provide a safe repository for radioactive wastes within one or more of these domes, a thorough understanding of the geohydrology needs to be obtained, and the hydrologic stability of the domes needs to be established for the expected life of the storage facility. Dissolution may exist at all four candidate salt domes, possibly through contact with Cretaceous or Tertiary aquifers, or through fault systems in the vicinity of the domes. Strata overlying and surrounding Palestine and Keechi Salt Domes have been arched into steeply-dipping folds that are complexly faulted. Similar conditions exist at Oakwood and Mount Sylvan Domes, except that the Tertiary strata have been only moderately disturbed. Additional problems concerning the hydrologic stability of Oakwood and Palestine Salt Domes have resulted from the disposal of oil-field salinewater in the cap rock at the Oakwood Dome and previous solution mining of salt at the Palestine Dome

  5. Stability of the accumulation pattern around Dome C over the last glacial cycle

    Science.gov (United States)

    Cavitte, Marie; Parrenin, Frédéric; Ritz, Catherine; Blankenship, Donald; Young, Duncan; Frezzotti, Massimo; Roberts, Jason; van Ommen, Tas

    2017-04-01

    The "Candidate A" region, just to the south of Dome C, is one of the climate community's targets for retrieving "old ice", aiming for an ice core bottom age of 1.5 million-years. The region lies along the divide that separates the Byrd and Totten glacier catchments, and thus its position could be sensitive to differential behavior of those two systems. In the winter of 15/16, the University of Texas at Austin Institute for Geophysics (UTIG) collected a detailed airborne radar survey known as OIA (Old Ice A) (Young et al., in review). Seventeen internal radar reflections are mapped through this survey, encompassing both sides of the divide, spanning the last three glacial cycles, from 38 ka and 366 kyrs. Dates are obtained where the internal reflections intersect the EPICA Dome C ice core and the AICC20112 age-depth chronology can be transferred to each individual reflection. These internal reflections are easily traced in the OIA survey for several reasons: (1) Candidate A is a region of relatively stable ice, close to the ice divide, so very little horizontal flow has occurred and the radar reflections exhibit near-horizontal stratigraphy, (2) the gridded geometry of the survey design implies a high number of crossovers which allow regular checks on the accuracy of the reflection mapping, and supports the isochronal character of the reflections. Older airborne UTIG radar surveys in the region augment the dataset to provide constraints further away from the divide, and the same set of isochrones are traced throughout (previously published in Cavitte et al., 2016). We use a 1D inverse model (Parrenin et al., in prep) to reconstruct the patterns of paleo-accumulation through time all the way back to the penultimate interglacial (127 kyr). To do this, we first fit the isochrones' geometries and ages to invert for the steady-state accumulation rate, the basal melting rate and the p exponent in the Lliboutry flow formulation. We then reconstruct paleo-accumulation rates

  6. Site specific study for possible ongoing salt dome movement

    International Nuclear Information System (INIS)

    Thoms, R.L.; Manning, T.A.; Paille, L.K.; Gehle, R.M.

    1977-01-01

    U.S. Gulf Coast salt domes, among other geologic structures, currently are being considered for storage of commercial radioactive wastes. A major concern with dome storage of long lived radioactive wastes lies with the possible tectonic movement of the host dome. Any ongoing movement of a salt dome can be monitored with a site specific complementary system of field instrumentation and finite element modelling. Field instrumentation and accompanying finite element analyses for a study dome in northwest Louisiana are described. Site specific data and early experience associated with tiltmeters over the dome are presented. Also, recommendations are made for modifications and extensions of the field instrumentation and finite element modelling appropriate to the specific site under study

  7. "Kaj" je Frederick Winslow Taylor = “What” is Frederick Winslow Taylor

    OpenAIRE

    Andrej Markovic

    2006-01-01

    Raising the issue of Taylor and his scientific management after less than a hundred years seems at first glance to be quite anachronistic. Today we are more likely to find Taylor’s works in antique shops than in the libraries of the schools of management. Has the memory of utilitarian and pragmatic managerial knowledge of a century back faded, or are we in a way ashamed of Taylor, the protagononist of management? How does the research into the origin and nature of management affect the effici...

  8. Identifying suitable piercement salt domes for nuclear waste storage sites

    International Nuclear Information System (INIS)

    Kehle, R.; e.

    1980-08-01

    Piercement salt domes of the northern interior salt basins of the Gulf of Mexico are being considered as permanent storage sites for both nuclear and chemically toxic wastes. The suitable domes are stable and inactive, having reached their final evolutionary configuration at least 30 million years ago. They are buried to depths far below the level to which erosion will penetrate during the prescribed storage period and are not subject to possible future reactivation. The salt cores of these domes are themselves impermeable, permitting neither the entry nor exit of ground water or other unwanted materials. In part, a stable dome may be recognized by its present geometric configuration, but conclusive proof depends on establishing its evolutionary state. The evolutionary state of a dome is obtained by reconstructing the growth history of the dome as revealed by the configuration of sedimentary strata in a large area (commonly 3,000 square miles or more) surrounding the dome. A high quality, multifold CDP reflection seismic profile across a candidate dome will provide much of the necessary information when integrated with available subsurface control. Additional seismic profiles may be required to confirm an apparent configuration of the surrounding strata and an interpreted evolutionary history. High frequency seismic data collected in the near vicinity of a dome are also needed as a supplement to the CDP data to permit accurate depiction of the configuration of shallow strata. Such data must be tied to shallow drill hole control to confirm the geologic age at which dome growth ceased. If it is determined that a dome reached a terminal configuration many millions of years ago, such a dome is incapable of reactivation and thus constitutes a stable storage site for nuclear wastes

  9. Midyear FY 1983 Richton Dome screening and suitability review

    International Nuclear Information System (INIS)

    1983-08-01

    The NWTS screening of Gulf Coast salt domes for suitable nuclear waste repository sites identified three candidate domes. These are, in order of preference, Richton Dome, Mississippi; Vacherie Dome, Louisiana; and Cypress Creek Dome, Mississippi. A qualitative review of information obtained since this initial ranking gives no basis for revising this ranking. A review of unresolved siting issues at Richton Dome shows siting concerns presently center on the geologic stability and hydrology suitability of Richton Dome and vicinity. Tectonic concerns of regional uplift and faulting are examined, as are salt tectonic concerns related to salt dome movement and dissolution. Both geologic and geodetic data suggest the Mississippi Salt Basin is experiencing uplift. However, uplift rates estimated from geologic evidence are an order of magnitude less than rates estimated from releveling data. Faults are present throughout much of the basin, and most are the result of horizontal and vertical movements of the Louann Salt during the Cretaceous and Early Tertiary. Several faults are present in the sediments surrounding Richton Dome, but current evidence suggests no movements have occurred since the Miocene. Richton Dome's hydrologic suitability is considered in analysis of the regional ground-water flow system. A three-dimensional, ground-water flow model has been utilized to calculate travel paths and travel times for releases of contaminants from various points on the dome. Based on model analyses, a release at repository level would take nearly 39,000 years to reach the upper aquifer and would eventually discharge into the Leaf River or upper reaches of the Pascagoula River over 50 km from the dome. This estimate of travel time greatly exceeds the minimum 1000 year travel time required by proposed Department of Energy (DOE) guidelines. 76 references

  10. Spatial Variability of Perchlorate along a Traverse Route from Zhongshan Station to Dome A, East Antarctica

    Science.gov (United States)

    Jiang, S.; Cole-Dai, J.; Li, Y.; An, C.

    2016-12-01

    Snow deposition and accumulation on the Antarctic ice sheet preserve records of climatic change, as well as those of chemical characteristics of the environment. Chemical composition of snow and ice cores can be used to track the sources of important substances including pollutants and to investigate relationships between atmospheric chemistry and climatic conditions. Recent development in analytical methodology has enabled the determination of ultra-trace levels of perchlorate in polar snow. We have measured perchlorate concentrations in surface snow samples collected along a traverse route from Zhongshan Station to Dome A in East Antarctica to determine the level of atmospheric perchlorate in East Antarctica and to assess the spatial variability of perchlorate along the traverse route. Results show that the perchlorate concentrations vary between 32 and 200 ng kg-1, with an average of 104.3 ng kg-1. And perchlorate concentration profile presents regional variation patterns along the traverse route. In the coastal region, perchlorate concentration displays an apparent decreasing relationship with increasing distance inland; it exhibits no apparent trend in the intermediate region from 200 to 1000 km. The inland region from 1000 to 1244 km presents a generally increasing trend of perchlorate concentration approaching the dome. Different rates of atmospheric production, dilution by snow accumulation and re-deposition of snow-emitted perchlorate (post-depositional change) are the three possible factors influencing the spatial variability of perchlorate over Antarctica.

  11. Richton Dome air quality analysis: Revision 2

    International Nuclear Information System (INIS)

    1985-11-01

    Detailed supporting calculations, methodology and results of the air quality analysis performed for the Richton Dome Environmental Assessment are presented in this report. Maximum emission rates during site characterization and repository construction and operation are analyzed and reported. The major source of emissions is fugitive dust from construction activities. Modeling was performed primarily with the US Environmental Protection Agency Industrial Source Complex (ISC) Model and meteorological data from Jackson, Mississippi. Predicted maximum ground level concentrations off site are presented. Supporting calculations and computer model runs are presented in appendixes. Salt deposition around the site was predicted and results and supporting analyses are presented. 4 refs., 1 fig., 21 tabs

  12. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling

    Directory of Open Access Journals (Sweden)

    O. Passalacqua

    2017-09-01

    Full Text Available Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF, which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice–bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km  ×  130 km area, with a N–S gradient and with values ranging from 48 to 60 mW m−2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF.

  13. Taylor Law in Wind Energy Data

    Directory of Open Access Journals (Sweden)

    Rudy Calif

    2015-10-01

    Full Text Available The Taylor power law (or temporal fluctuation scaling, is a scaling relationship of the form σ ~  (Pλ where !! is the standard deviation and hPi the mean value of a sample of a time series has been observed for power output data sampled at 5 min and 1 s and from five wind farms and a single wind turbine, located at different places. Furthermore, an analogy with the turbulence field is performed, consequently allowing the establishment of a scaling relationship between the turbulent production IP and the mean value (P.

  14. Predictability of Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Viecelli, J.A.

    1986-01-01

    Numerical experiments modeling the Rayleigh Taylor instability are carried out using a two-dimensional incompressible Eulerian hydrodynamic code VFTS. The method of integrating the Navier-Stokes equations including the viscous terms is similar to that described in Kim and Moin, except that Lagrange particles have been added and provision for body forces is given. The Eulerian method is 2nd order accurate in both space and time, and the Poisson equation for the effective pressure field is solved exactly at each time step using a cyclic reduction method. 3 refs., 3 figs

  15. Liquidity Traps with Global Taylor Rules

    OpenAIRE

    Stephanie Schmitt-Grohe; Martin Uribe

    2000-01-01

    A key result of a recent literature that focuses on the global consequences of Taylor-type interest rate feedback rules is that such rules, in combination with the zero-bound on nominal interest rates, can lead to unintended liquidity traps. An immediate question posed by this result is whether the government could avoid liquidity traps by ignoring the zero-bound, that is, by threatening to set the nominal interest rate at a negative value should the inflation rate fall below a certain thresh...

  16. Inward propagating chemical waves in Taylor vortices.

    Science.gov (United States)

    Thompson, Barnaby W; Novak, Jan; Wilson, Mark C T; Britton, Melanie M; Taylor, Annette F

    2010-04-01

    Advection-reaction-diffusion (ARD) waves in the Belousov-Zhabotinsky reaction in steady Taylor-Couette vortices have been visualized using magnetic-resonance imaging and simulated using an adapted Oregonator model. We show how propagating wave behavior depends on the ratio of advective, chemical and diffusive time scales. In simulations, inward propagating spiral flamelets are observed at high Damköhler number (Da). At low Da, the reaction distributes itself over several vortices and then propagates inwards as contracting ring pulses--also observed experimentally.

  17. Nonlinear saturation of the Rayleigh Taylor instability

    International Nuclear Information System (INIS)

    Das, A.; Mahajan, S.; Kaw, P.; Sen, A.; Benkadda, S.; Verga, A.

    1997-01-01

    The problem of the nonlinear saturation of the 2 dimensional Rayleigh Taylor instability is re-examined to put various earlier results in a proper perspective. The existence of a variety of final states can be attributed to the differences in the choice of boundary conditions and initial conditions in earlier numerical modeling studies. Our own numerical simulations indicate that the RT instability saturates by the self consistent generation of shear flow even in situations (with periodic boundaries) where, in principle, an infinite amount of gravitational energy can be tapped. Such final states can be achieved for suitable values of the Prandtl number. (author)

  18. Ice Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice...

  19. A cosmological Slavnov-Taylor identity

    Science.gov (United States)

    Collins, Hael; Holman, R.; Vardanyan, Tereza

    2014-12-01

    We develop a method for treating the consistency relations of inflation that includes the full time-evolution of the state. This approach relies only on the symmetries of the inflationary setting, in particular a residual conformal symmetry in the spatial part of the metric, along with general properties which hold for any quantum field theory. As a result, the consistency relations that emerge, which are essentially the Slavnov-Taylor identities associated with this residual conformal symmetry, apply very generally: they are true of the full Green's functions, hold largely independently of the particular inflationary model, and can be used for arbitrary states. We illustrate these techniques by showing the form assumed by the standard consistency relation between the two and three-point functions for the primordial scalar fluctuations when they are in a Bunch-Davies state. But because we have included the full evolution of the state, this approach works for a general initial state as well and does not need to have assumed that inflation began in the Bunch-Davies state. We explain how the Slavnov-Taylor identity is modified for these more general states.

  20. Saffman-Taylor fingers with kinetic undercooling

    KAUST Repository

    Gardiner, Bennett P. J.

    2015-02-23

    © 2015 American Physical Society. The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularization on the interface is not provided by surface tension but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalize high velocities and prevent blow-up of the unregularized solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this "selection" of 1/2 by kinetic undercooling is qualitatively similar to the well-known analog with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analog with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension and numerically taking the limit that the surface tension vanishes.

  1. Saffman-Taylor fingers with kinetic undercooling

    KAUST Repository

    Gardiner, Bennett P. J.; McCue, Scott W.; Dallaston, Michael C.; Moroney, Timothy J.

    2015-01-01

    © 2015 American Physical Society. The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularization on the interface is not provided by surface tension but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalize high velocities and prevent blow-up of the unregularized solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this "selection" of 1/2 by kinetic undercooling is qualitatively similar to the well-known analog with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analog with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension and numerically taking the limit that the surface tension vanishes.

  2. Slavnov-Taylor constraints for nontrivial backgrounds

    International Nuclear Information System (INIS)

    Binosi, D.; Quadri, A.

    2011-01-01

    We devise an algebraic procedure for the evaluation of Green's functions in SU(N) Yang-Mills theory in the presence of a nontrivial background field. In the ghost-free sector the dependence of the vertex functional on the background is shown to be uniquely determined by the Slavnov-Taylor identities in terms of a certain 1-PI correlator of the covariant derivatives of the ghost and the antighost fields. At nonvanishing background this amplitude is shown to encode the quantum deformations to the tree-level background-quantum splitting. The approach only relies on the functional identities of the model (Slavnov-Taylor identities, b-equation, antighost equation) and thus it is valid beyond perturbation theory, and, in particular, in a lattice implementation of the background field method. As an example of the formalism we analyze the ghost two-point function and the Kugo-Ojima function in an instanton background in SU(2) Yang-Mills theory, quantized in the background Landau gauge.

  3. Ice Cream

    NARCIS (Netherlands)

    Scholten, E.

    2014-01-01

    Ice cream is a popular dessert, which owes its sensorial properties (mouth feel) to its complex microstructure. The microstructure is a result of the combination of the ingredients and the production process. Ice cream is produced by simultaneous freezing and shearing of the ice cream mix, which

  4. Ice targets

    International Nuclear Information System (INIS)

    Pacheco, C.; Stark, C.; Tanaka, N.; Hodgkins, D.; Barnhart, J.; Kosty, J.

    1979-12-01

    This report presents a description of ice targets that were constructed for research work at the High Resolution Spectrometer (HRS) and at the Energetic Pion Channel and Spectrometer (EPICS). Reasons for using these ice targets and the instructions for their construction are given. Results of research using ice targets will be published at a later date

  5. Geology--hydrology of Avery Island Salt Dome

    International Nuclear Information System (INIS)

    Jacoby, C.H.

    1977-07-01

    After a review of the geology of the Gulf Coast salt domes, the geology (geomorphology and tectonics) and hydrology of Avery Island Dome, 10 miles south-southwest of New Iberia, Louisiana, were studied in detail. Rock mechanics were studied using grouts and piezometers. 17 figs

  6. SOLUTION MINING IN SALT DOMES OF THE GULF COAST EMBAYMENT

    Energy Technology Data Exchange (ETDEWEB)

    Griswold, G. B.

    1981-02-01

    Following a description of salt resources in the salt domes of the gulf coast embayment, mining, particularly solution mining, is described. A scenario is constructed which could lead to release of radioactive waste stored in a salt dome via inadvertent solution mining and the consequences of this scenario are analyzed.

  7. Evaluation of the structure and stratigraphy over Richton Dome, Mississippi

    International Nuclear Information System (INIS)

    Werner, M.L.

    1986-05-01

    The structure and stratigraphy over Richton Salt Dome, Mississippi, have been evaluated from 70 borings that were completed to various depths above the dome. Seven lithologic units have been identified and tentatively correlated with the regional Tertiary stratigraphy. Structure-contour and thickness maps of the units show the effects of dome growth from Eocene through early Pliocene time. Growth of the salt stock from late Oligocene through early Pliocene is estimated to have averaged 0.6 to 2.6 centimeters (0.2 to 1.1 inches) per 1000 years. No dome growth has occurred since the early Pliocene. The late Oligocene to early Pliocene strata over and adjacent to the dome reflect arching over the entire salt stock; some additional arching over individual centers may represent pre-Quaternary differential movement in the salt stock. The lithology and structure of the caprock at the Richton Salt Dome indicate that the caprock probably was completely formed by late Oligocene. In late Oligocene, the caprock was fractured by arching and altered by gypsum veining. Since late Oligocene, there are no indications of significant hydrologic connections through the caprock - that is, there are no indications of dissolution collapse or further anhydrite caprock accumulation. This structural and stratigraphic analysis provides insights on dome growth history, dome geometry, and neardome hydrostratigraphy that will aid in planning site characterization field activities, including an exploratory shaft, and in the conceptual design of a high-level waste (HLW) repository

  8. Wide-scan dielectric dome antenna with reduced profile

    NARCIS (Netherlands)

    Gandini, E.; Silvestri, F.; Benini, A.; Gerini, G.; Martini, E.; Maci, S.; Viganò, M.C.; Toso, G.; Monni, S.

    2017-01-01

    In this contribution, a dielectric dome antenna design in Ka-band is presented. The dome antenna is based on the combination of a phased array and a dielectric lens. The goal of the combination of these structures is to enlarge the field of view of the antenna. In particular, the array is considered

  9. Geologic study of Kettle dome, northeast Washington. Final report

    International Nuclear Information System (INIS)

    1980-10-01

    This geologic study of Kettle dome, northeast Washington, encompasses an area of approximately 800 square miles (2048 sq km). The evaluation of uranium occurrences associated with the igneous and metamorphic rocks of the dome and the determination of the relationship between uranium mineralization and stratigraphic, structural, and metamorphic features of the dome are the principal objectives. Evaluation of the validity of a gneiss dome model is a specific objective. The principal sources of data are detailed geologic mapping, surface radiometric surveys, and chemical analyses of rock samples. Uranium mineralization is directly related to the presence of pegmatite dikes and sills in biotite gneiss and amphibolite. Other characteristics of the uranium occurrences include the associated migmatization and high-grade metamorphism of wallrock adjacent to the pegmatite and the abrupt decrease in uranium mineralization at the pegmatite-gneiss contact. Subtle chemical characteristics found in mineralized pegmatites include: (1) U increase as K 2 O increases, (2) U decreases as Na 2 O increases, and (3) U increases as CaO increases at CaO values above 3.8%. The concentration of uranium occurrences in biotite gneiss and amphibolite units results from the preferential intrusion of pegmitites into these well-foliated rocks. Structural zones of weakness along dome margins permit intrusive and migmatitic activity to affect higher structural levels of the dome complex. As a result, uranium mineralization is localized along dome margins. The uranium occurrences in the Kettle dome area are classified as pegmatitic. Sufficient geologic similarities exist between Kettle dome and the Rossing uranium deposit to propose the existence of economic uranium targets within Kettle dome

  10. The Discovery Dome: A Tool for Increasing Student Engagement

    Science.gov (United States)

    Brevik, Corinne

    2015-04-01

    The Discovery Dome is a portable full-dome theater that plays professionally-created science films. Developed by the Houston Museum of Natural Science and Rice University, this inflatable planetarium offers a state-of-the-art visual learning experience that can address many different fields of science for any grade level. It surrounds students with roaring dinosaurs, fascinating planets, and explosive storms - all immersive, engaging, and realistic. Dickinson State University has chosen to utilize its Discovery Dome to address Earth Science education at two levels. University courses across the science disciplines can use the Discovery Dome as part of their curriculum. The digital shows immerse the students in various topics ranging from astronomy to geology to weather and climate. The dome has proven to be a valuable tool for introducing new material to students as well as for reinforcing concepts previously covered in lectures or laboratory settings. The Discovery Dome also serves as an amazing science public-outreach tool. University students are trained to run the dome, and they travel with it to schools and libraries around the region. During the 2013-14 school year, our Discovery Dome visited over 30 locations. Many of the schools visited are in rural settings which offer students few opportunities to experience state-of-the-art science technology. The school kids are extremely excited when the Discovery Dome visits their community, and they will talk about the experience for many weeks. Traveling with the dome is also very valuable for the university students who get involved in the program. They become very familiar with the science content, and they gain experience working with teachers as well as the general public. They get to share their love of science, and they get to help inspire a new generation of scientists.

  11. 78 FR 12307 - Taylor, G. Tom; Notice of Filing

    Science.gov (United States)

    2013-02-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ID-5705-001] Taylor, G. Tom; Notice of Filing Take notice that on February 14, 2013, G. Tom Taylor filed an application to hold interlocking positions pursuant to section 305(b) of the Federal Power Act, 16 U.S.C. 825d(b), Part 45 of the...

  12. DSM-5 and ADHD - an interview with Eric Taylor.

    Science.gov (United States)

    Taylor, Eric

    2013-09-12

    In this podcast we talk to Prof Eric Taylor about the changes to the diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) in DSM-5 and how these changes will affect clinical practice. The podcast for this interview is available at: http://www.biomedcentral.com/sites/2999/download/Taylor.mp3.

  13. G.I. Taylor and the Trinity Test

    Science.gov (United States)

    Deakin, Michael A. B.

    2011-01-01

    The story is often told of the calculation by G.I. Taylor of the yield of the first ever atomic bomb exploded in New Mexico in 1945. It has indeed become a staple of the classroom whenever dimensional analysis is taught. However, while it is true that Taylor succeeded in calculating this figure at a time when it was still classified, most versions…

  14. Animating Nested Taylor Polynomials to Approximate a Function

    Science.gov (United States)

    Mazzone, Eric F.; Piper, Bruce R.

    2010-01-01

    The way that Taylor polynomials approximate functions can be demonstrated by moving the center point while keeping the degree fixed. These animations are particularly nice when the Taylor polynomials do not intersect and form a nested family. We prove a result that shows when this nesting occurs. The animations can be shown in class or…

  15. Upheaval Dome, Utah, USA: Impact origin confirmed

    Science.gov (United States)

    Buchner, Elmar; Kenkmann, Thomas

    2008-03-01

    Upheaval Dome is a unique circular structure on the ColoradoPlateau in SE Utah, the origin of which has been controversiallydiscussed for decades. It has been interpreted as a crypto volcanicfeature, a salt diapir, a pinched-off salt diapir, and an erodedimpact crater. While recent structural mapping, modeling, andanalyses of deformation mechanisms strongly support an impactorigin, ultimate proof, namely the documentation of unambiguousshock features, has yet to be successfully provided. In thisstudy, we document, for the first time, shocked quartz grainsfrom this crater in sandstones of the Jurassic Kayenta Formation.The investigated grains contain multiple sets of decorated planardeformation features. Transmission electron microscopy (TEM)reveals that the amorphous lamellae are annealed and exhibitdense tangles of dislocations as well as trails of fluid inclusions.The shocked quartz grains were found in the periphery of thecentral uplift in the northeastern sector of the crater, whichmost likely represents the cross range crater sector.

  16. The Lifferth Dome for Small Telescopes

    Science.gov (United States)

    Wilson, B. L.; Olsen, C. S.; Iverson, E. P.; Paget, A.; Lifferth, W.; Brown, P. J.; Moody, J. W.

    2004-12-01

    The Lifferth Dome is a pull-off roof designed for small telescopes and other observational equipment. It was specifically designed for the needs of the ROVOR project. The roof itself is completely removed from the observatory housing walls and cranked off to the side below the optical horizon. This is done using two swing arms on either side of the observatory that work in unison to lift the roof off the structure and rotate down and away into a cleared location. The torque is provided by a threaded rod connected to an electric motor at the back of the building. As the motor rotates, the threads turn through a threaded sleeve connected directly to the support arms. Advantages to this design are no lost horizon, no roller surfaces to keep clean, low power and simple limit switches. Operation is by computer control using by National Instruments LabVIEW via the internet. We present its design and construction.

  17. Taylor series maps and their domain of convergence

    International Nuclear Information System (INIS)

    Abell, D.T.; Dragt, A.J.

    1992-01-01

    This paper tries to make clear what limits the validity of a Taylor series map, and how. We describe the concept of a transfer map and quote some theorems that justify not only their existence but also their advantages. Then, we describe the Taylor series representation for transfer maps. Following that, we attempt to elucidate some of the basic theorems from the theory of functions of one and several complex variables. This material forms the core of our understanding of what limits the domain of convergence of Taylor series maps. Lastly, we use the concrete example of a simple anharmonic oscillator to illustrate how the theorems from several complex variable theory affect the domain convergence of Taylor series maps. There we describe the singularities of the anharmonic oscillator in the complex planes of the initial conditions, show how they constrain our use of a Taylor series map, and then discuss our findings

  18. String-theoretic deformation of the Parke-Taylor factor

    Science.gov (United States)

    Mizera, Sebastian; Zhang, Guojun

    2017-09-01

    Scattering amplitudes in a range of quantum field theories can be computed using the Cachazo-He-Yuan (CHY) formalism. In theories with color ordering, the key ingredient is the so-called Parke-Taylor factor. In this paper we give a fully SL (2 ,C )-covariant definition and study the properties of a new integrand called the "string Parke-Taylor" factor. It has an α' expansion whose leading coefficient is the field-theoretic Parke-Taylor factor. Its main application is that it leads to a CHY formulation of open string tree-level amplitudes. In fact, the definition of the string Parke-Taylor factor was motivated by trying to extend the compact formula for the first α' correction found by He and Zhang, while the main ingredient in its definition is a determinant of a matrix introduced in the context of string theory by Stieberger and Taylor.

  19. Taylor dispersion in wind-driven current

    Science.gov (United States)

    Li, Gang; Wang, Ping; Jiang, Wei-Quan; Zeng, Li; Li, Zhi; Chen, G. Q.

    2017-12-01

    Taylor dispersion associated with wind-driven currents in channels, shallow lakes and estuaries is essential to hydrological environmental management. For solute dispersion in a wind-driven current, presented in this paper is an analytical study of the evolution of concentration distribution. The concentration moments are intensively derived for an accurate presentation of the mean concentration distribution, up to the effect of kurtosis. The vertical divergence of concentration is then deduced by Gill's method of series expansion up to the fourth order. Based on the temporal evolution of the vertical concentration distribution, the dispersion process in the wind-driven current is concretely characterized. The uniform shear leads to a special symmetrical distribution of mean concentration free of skewness. The non-uniformity of vertical concentration is caused by convection and smeared out gradually by the effect of diffusion, but fails to disappear even at large times.

  20. Reverse Taylor Tests on Ultrafine Grained Copper

    International Nuclear Information System (INIS)

    Mishra, A.; Meyers, M. A.; Martin, M.; Thadhani, N. N.; Gregori, F.; Asaro, R. J.

    2006-01-01

    Reverse Taylor impact tests have been carried out on ultrafine grained copper processed by Equal Channel Angular Pressing (ECAP). Tests were conducted on an as-received OFHC Cu rod and specimens that had undergone sequential ECAP passes (2 and 8). The average grain size ranged from 30 μm for the initial sample to less than 0.5 μm for the 8-pass samples. The dynamic deformation states of the samples, captured by high speed digital photography were compared with computer simulations run in AUTODYN-2D using the Johnson-Cook constitutive equation with constants obtained from stress-strain data and by fitting to an experimentally measured free surface velocity trace. The constitutive response of copper of varying grain sizes was obtained through quasistatic and dynamic mechanical tests and incorporation into constitutive models

  1. PENGEMBANGAN DESA WISATA RUMAH DOME BERBASIS AGROINDUSTRI PANGAN LOKAL (Kajian Diversifikasi Ketela Pohon di Desa Wisata Rumah Dome Prambanan

    Directory of Open Access Journals (Sweden)

    Susi Wuri Ani

    2013-11-01

    Full Text Available Pangan merupakan kebutuhan utama dalam kehidupan manusia. Pemenuhan kebutuhan pangan baik dari segi jumlah, mutu, gizi maupun keamanan berkaitan dengan Sumberdaya Manusia (SDM. Kualitas konsumsi pangan dan gizi masyarakat menentukan SDM masyarakat tersebut. Agroindustri pangan lokal merupakan kegiatan yang memberdayakan sumberdaya lokal (indigenous resources. Seluruh potensi lokal dimanfaatkan untuk menguatkan agroindustri pangan lokal. Penduduk di kawasan wisata Rumah Dome belum mampu mengolah bahan pangan lokal. Kegiatan ini bertujuan membentuk kelompok usaha produktif Ibu-Ibu PKK di Rumah Dome untuk dapat meningkatkan nilai ekonomis pangan lokal (ketela pohon. Hal yang dilakukan adalah memberikan pelatihan pengolahan ketela pohon menjadi ceriping singkong berbagai rasa, keripik belut daun singkong, membuat brownies berbahan tepung ketela, mengemas produk dengan brand Rumah Dome dan memberikan pelatihan pembukuan sederhana. Dengan kegiatan ini diharapkan akan tumbuh kelompok usaha produktif sehingga dapat mengangkat citra wisata Rumah Dome dan meningkatkan pendapatan masyarakat di Rumah Dome. Abstract Food is a major necessity in human life. Food needs are important for human resource (HR both in terms of quantity and quality. Quality of food consumption and nutrition communities determine the HR community. Local food agroindustry is an activity that empowers local resources (indigenous resources. The whole potential of local food used to strengthen local agroindustry. Residents in the tourist area of Dome House have not been able to process local food. This activity aims to establish productive business of woman group (PKK in Dome House to increase the economic value of local food (cassava. The activities are training for production process, packaging with Dome House’s brand and simple accounting management. The cassava processing training are: (1 making variety flavors of cassava chips; (2 producing eel chips from cassava leaves and (3

  2. Pinch instabilities in Taylor-Couette flow.

    Science.gov (United States)

    Shalybkov, Dima

    2006-01-01

    The linear stability of the dissipative Taylor-Couette flow with an azimuthal magnetic field is considered. Unlike ideal flows, the magnetic field is a fixed function of a radius with two parameters only: a ratio of inner to outer cylinder radii, eta, and a ratio of the magnetic field values on outer and inner cylinders, muB. The magnetic field with 0rotation. The unstable modes are located into some interval of the axial wave numbers for the flow stable without magnetic field. The interval length is zero for a critical Hartmann number and increases with an increasing Hartmann number. The critical Hartmann numbers and length of the unstable axial wave number intervals are the same for every rotation law. There are the critical Hartmann numbers for m=0 sausage and m=1 kink modes only. The sausage mode is the most unstable mode close to Ha=0 point and the kink mode is the most unstable mode close to the critical Hartmann number. The transition from the sausage instability to the kink instability depends on the Prandtl number Pm and this happens close to one-half of the critical Hartmann number for Pm=1 and close to the critical Hartmann number for Pm=10(-5). The critical Hartmann numbers are smaller for kink modes. The flow stability does not depend on magnetic Prandtl numbers for m=0 mode. The same is true for critical Hartmann numbers for both m=0 and m=1 modes. The typical value of the magnetic field destabilizing the liquid metal Taylor-Couette flow is approximately 10(2) G.

  3. Educar na autenticidade em Charles Taylor = Educating in the authenticity in Charles Taylor

    Directory of Open Access Journals (Sweden)

    Foschiera, Rogério

    2009-01-01

    Full Text Available Analiso a perspectiva tayloriana da autencidade através de uma hermenêutica de suas principais obras para propor o significado de educar na autencticidade a partir de Charles Taylor. Com autencidade e ontologia moral Taylor apresenta uma antropologia ancorada na moral e na ontologia. Com autencidade e epistemologia se percebe que a perspectiva da autencidade não exclui o paradigma científico, mas necessita de outros paradigmas, principalmente do hermenêutico. Com autencidade e linguagem evidencio a compreensão de Taylor sobre a natureza da linguagem e o destaque que ele dá á definição de ser humano como "animal portador de logos", bem como o significado e as decorrências da perspectiva expressivista. Duas políticas: a da igualdade de direitos de todos e a do reconhecimento das diferenças estão integradas na perspectiva tayloriana da autencidade. Necessariamente, o ser humano, para ser autêntico, estará em constante referência a horizontes de sentido que transcendem o indivíduo, é o que apresento com autencidade e transcendência

  4. "Kaj" je Frederick Winslow Taylor = “What” is Frederick Winslow Taylor

    Directory of Open Access Journals (Sweden)

    Andrej Markovic

    2006-06-01

    Full Text Available Raising the issue of Taylor and his scientific management after less than a hundred years seems at first glance to be quite anachronistic. Today we are more likely to find Taylor’s works in antique shops than in the libraries of the schools of management. Has the memory of utilitarian and pragmatic managerial knowledge of a century back faded, or are we in a way ashamed of Taylor, the protagononist of management? How does the research into the origin and nature of management affect the efficiency of a particular manager, which seems to be the objective of management education? What is the difference between Taylor's management and contemporary management? Is it merely less scientific in approach? And where is modern management developing, if no longer in the field of exact science? And where do key notions of contemporary management, like ‘mission’ and ‘vision’ belong? Has management since its beginings proved to be only knowledge for managing organizations, or does it go beyond that? In a brief analysis of Taylor’s scientific management the author of the article tries to answer the above mentioned questions. Some of the questions are, however, only touched upon, awaiting an answer in the future.

  5. Gut-associated Lymphoid Tissue (GALT) Carcinoma or Dome Carcinoma?

    Science.gov (United States)

    Rubio, Carlos A; Schmidt, Peter T

    2016-10-01

    The vast majority of colorectal carcinomas (CRCs) evolve from mucosa not associated to lymphoid tissues aggregates via the adenoma-carcinoma sequence or via the serrated pathway. Rarely CRCs evolve from gut mucosa associated to lymphoid tissue (GALT). Based on the presence of a circumscribed elevation in the colorectal mucosa, GALT carcinomas are also referred to as dome carcinomas (DC). Descriptions of the surface mucosa covering 21 GALT-CRCs appearing in pathological reports were reviewed. Three of the 21 GALT-CRCs fulfilled the criteria of dome carcinoma. Of the remaining 18 GALT-CRCs, nine were described as polypoid lesions, five as plaque-like lesions, two as sessile elevated lesions or mass, one as ulcerated and one as histological finding. Hence, only 14.3% (n=3) of the 21 GALT-CRCs displayed a dome configuration, whereas the majority, 85.7% (n=18), exhibited structures other than dome shapes at gross or at histologic examination. It becomes apparent that by using "dome" in addressing carcinomas in the colorectal mucosa, many cases of GALT carcinomas might be overlooked. Another drawback of using the "dome" nomenclature is that dome-like outlines may be detected in small metastatic tumors in the submucosa or in small colorectal carcinomas not arising from GALT mucosa. Instead, by using "GALT carcinoma", that is the histologic diagnosis in addressing these neoplasias, all cases of GALT-CRCs will be included. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  6. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  7. Taylor's series method for solving the nonlinear point kinetics equations

    International Nuclear Information System (INIS)

    Nahla, Abdallah A.

    2011-01-01

    Highlights: → Taylor's series method for nonlinear point kinetics equations is applied. → The general order of derivatives are derived for this system. → Stability of Taylor's series method is studied. → Taylor's series method is A-stable for negative reactivity. → Taylor's series method is an accurate computational technique. - Abstract: Taylor's series method for solving the point reactor kinetics equations with multi-group of delayed neutrons in the presence of Newtonian temperature feedback reactivity is applied and programmed by FORTRAN. This system is the couples of the stiff nonlinear ordinary differential equations. This numerical method is based on the different order derivatives of the neutron density, the precursor concentrations of i-group of delayed neutrons and the reactivity. The r th order of derivatives are derived. The stability of Taylor's series method is discussed. Three sets of applications: step, ramp and temperature feedback reactivities are computed. Taylor's series method is an accurate computational technique and stable for negative step, negative ramp and temperature feedback reactivities. This method is useful than the traditional methods for solving the nonlinear point kinetics equations.

  8. An independently dated 2000-yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the 1450s CE eruption of Kuwae, Vanuatu

    Directory of Open Access Journals (Sweden)

    C. T. Plummer

    2012-11-01

    Full Text Available Volcanic eruptions are an important cause of natural climate variability. In order to improve the accuracy of climate models, precise dating and magnitude of the climatic effects of past volcanism are necessary. Here we present a 2000-yr record of Southern Hemisphere volcanism recorded in ice cores from the high accumulation Law Dome site, East Antarctica. The ice cores were analysed for a suite of chemistry signals and are independently dated via annual layer counting, with 11 ambiguous years at 23 BCE, which has presently the lowest error of all published long Antarctic ice cores. Independently dated records are important to avoid circular dating where volcanic signatures are assigned a date from some external information rather than using the date it is found in the ice core. Forty-five volcanic events have been identified using the sulphate chemistry of the Law Dome record. The low dating error and comparison with the NGRIP (North Greenland Ice Core Project volcanic records (on the GICC05 timescale suggest Law Dome is the most accurately dated Antarctic volcanic dataset, which will improve the dating of individual volcanic events and potentially allow better correlation between ice core records, leading to improvements in global volcanic forcing datasets. One of the most important volcanic events of the last two millennia is the large 1450s CE event, usually assigned to the eruption of Kuwae, Vanuatu. In this study, we review the evidence surrounding the presently accepted date for this event, and make the case that two separate eruptions have caused confusion in the assignment of this event. Volcanic sulphate deposition estimates are important for modelling the climatic response to eruptions. The largest volcanic sulphate events in our record are dated at 1458 CE (Kuwae?, Vanuatu, 1257 and 422 CE (unidentified.

  9. Correlation of Fracture Behavior With Microstructure in Friction Stir Welded, and Spin Formed AI-Li 2195 Domes

    Science.gov (United States)

    Tayon, Wesley A.; Domack, Marcia S.; Hales, Stephen J.

    2012-01-01

    Single-piece, spin-formed domes manufactured from friction stir welded (FSW) plates of Al-Li alloy 2195 have the potential to reduce the cost of fabricating cryogenic propellant tanks. Mechanical properties in the completed domes can be related directly to the final material condition and the microstructures developed. However, these new fabrication techniques have resulted in unexpected material challenges, such as abnormal grain growth in the weld nugget and the propensity for fracture in the adjacent thermo-mechanically affected zone (TMAZ). In this study, the microstructure and texture transformations within the TMAZ are related to fracture location in the vicinity of the weldment. The texture variations in the TMAZ are caused primarily by the varying amounts of shear deformation introduced during the FSW process. Grain morphology and microtexture characteristics are examined as a function of location in the TMAZ via electron backscatter diffraction (EBSD). A strong correlation between fracture location and the presence of texture banding in the TMAZ is observed. The fracture path tends to follow a distinct region of low Taylor Factor (TF) grains.

  10. Building Guastavino dome in China: A historical survey of the dome of the Auditorium at Tsinghua University

    Directory of Open Access Journals (Sweden)

    Yishi Liu

    2014-06-01

    The first part combs up the intellectual origins and precedents of the campus planning by Henry Murphy. As the dome is a focal point of the study, a brief course on the history of dome construction in the West is needed. The third part, based upon field measurement in July 2013, compares the actual dome with its original design featured by the Guastavino method, deducing possible reasons that resulted in the differences, including architect׳s unfamiliarity with Guastavino Company and its parameters, considerations about cost, and local construction tradition.

  11. Dynamic Transition and Pattern Formation in Taylor Problem

    Institute of Scientific and Technical Information of China (English)

    Tian MA; Shouhong WANG

    2010-01-01

    The main objective of this article is to study both dynamic and structural transitions of the Taylor-Couette flow,by using the dynamic transition theory and geometric theory of incompressible flows developed recently by the authors.In particular,it is shown that as the Taylor number crosses the critical number,the system undergoes either a continuous or a jump dynamic transition,dictated by the sign of a computable,nondimensional parameter R.In addition,it is also shown that the new transition states have the Taylor vortex type of flow structure,which is structurally stable.

  12. Effects of shock waves on Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Zhang Yongtao; Shu Chiwang; Zhou Ye

    2006-01-01

    A numerical simulation of two-dimensional compressible Navier-Stokes equations using a high-order weighted essentially nonoscillatory finite difference shock capturing scheme is carried out in this paper, to study the effect of shock waves on the development of Rayleigh-Taylor instability. Shocks with different Mach numbers are introduced ahead or behind the Rayleigh-Taylor interface, and their effect on the transition to instability is demonstrated and compared. It is observed that shock waves can speed up the transition to instability for the Rayleigh-Taylor interface significantly. Stronger shocks are more effective in this speed-up process

  13. Transparent Yttria for IR Windows and Domes - Past and Present

    National Research Council Canada - National Science Library

    Hogan, Patrick; Stefanik, Todd; Willingham, Charles; Gentilman, Richard

    2004-01-01

    ...) atmospheric transmission band at both ambient and elevated temperatures. Current state-of-the-art yttria's thermomechanical properties are adequate for a number of IR window and dome applications, but only marginal for the most demanding missions...

  14. Geological and hydrological exploration of Gulf Coast Salt Domes

    International Nuclear Information System (INIS)

    Laughon, R.B.

    1979-01-01

    The geologic exploration program in the Gulf Coast Salt Dome Region is based on a screening process that includes a series of increasingly detailed studies. The screening procedure takes the following steps: (1) determination of regions for further study (in this case, the salt domes of the interior Gulf Coast); (2) regional surveys and the determination of areas within those regions which are thought to be most suitable and which are recommended for further evaluation (in this case, eight specific salt domes); (3) area characterizations and the determination of locations within the areas which are thought to have a high probability of suitability (in this case, two or three of the eight salt domes); (4) location studies and the determination of a potential repository site, which is thought to be suitable and licensable and which is recommended for completion of site characterization studies

  15. Richton Dome noise analysis: Revision 2

    International Nuclear Information System (INIS)

    1985-11-01

    A study was performed as part of the Civilian Radioactive Waste Management Program to quantify the level and effect of noise from the various major phases of development of the proposed potentially acceptable nuclear waste repository site at Richton Dome, Mississippi. This report contains the results of a predictive noise level study for the site characterization, repository construction, and repository operational phases. Included herein are graphic representations of energy averaged day/night sound levels representing impact zones expected during each phase. Sound levels from onsite and offsite activity including traffic on highways and railroad routes are presented in isopleth maps. A description of the Environmental Noise Prediction Model used for the study, the study basis and methodologies, and actual modeling data are provided. Noise and vibration levels from blasting are also predicted and evaluated. Protective noise criteria containing a margin of safety are used for persons in relation to residences, schools, churches, and agricultural areas. Protective ground motion criteria for residential dwelling and for human annoyance are used in the evaluation. The evaluation provides the bases for assessing the noise impacts from the related activities at the proposed repository. 24 refs., 8 figs., 8 tabs

  16. Dome shaped features on Europa's surface

    Science.gov (United States)

    1997-01-01

    The Solid State Imaging system aboard the spacecraft Galileo took this image of the surface of Europa on February 20, 1997 during its sixth orbit around Jupiter. The image is located near 16 North, 268 West; illumination is from the lower-right. The area covered is approximately 48 miles (80 kilometers) by 56 miles (95 kilometers) across. North is toward the top of the image.This image reveals that the icy surface of Europa has been disrupted by ridges and faults numerous times during its past. These ridges have themselves been disrupted by the localized formation of domes and other features that may be indicative of thermal upwelling of water from beneath the crust. These features provide strong evidence for the presence of subsurface liquid during Europa's recent past.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  17. Analysis of tiltmeter monitoring of Northern Louisiana salt domes

    International Nuclear Information System (INIS)

    Waldon, M.G.; Thoms, R.L.

    1983-01-01

    Data were recorded at several tiltmeter sites in Northern Louisiana in the vicinity of Vacherie and Rayburn's salt domes. The objective of this data recording and subsequent analysis was to determine, if possible, the present rate of dome vertical movement, or to attempt to establish an upper bound to movement if undetectably small. Biaxial tiltmeters utilized were calibrated to detect extremely small tilts about two principal axes. No statistically significant tilting was observed during this survey. 13 references

  18. THEMIS Observations of Domes and Associated Lineaments in Arcadia Planitia

    Science.gov (United States)

    Milam, K. A.; McSween, H. Y.

    2003-12-01

    The northern plains of Mars contain several high concentrations (Acidalia, Utopia, Elysium, etc.) of small (System (THEMIS), visible images from THEMIS and the Mars Orbiter Camera, and elevation data from the Mars Orbiter Laser Altimeter were used to study a 390,000 km 2 area ˜1500 km to the northwest of Elysium Mons. Of interest is a region centered on Tyndall crater and bordered by Phlegras Montes to the west. The area is characterized by gentle, westward-sloping plains, with noticeable slope breaks along several N-S trending wrinkle ridges. Several hundred circular domes dot this area. Domes display features consistent with a volcanic origin. Most are circular to slightly elliptical at their base, with basal diameters ranging from 0.5-6 km. Summits typically rise material (as compared to the coarser-grained summits). Less than 25% of domes appear to have summit depressions and ~ 1% show fractured summit areas. Some domes appear to be randomly distributed, but many are aligned in chains according to wrinkle ridge orientations. Using THEMIS data, we have detected over 165 domes that are aligned with and superimposed upon over 145 lineaments. Most lineaments are cut by lineaments. No laterally extensive flows have been detected as emanating from lineaments, nor have similar lineaments been detected immediately outside the study area. The association of domes and lineaments is consistent with observations of volcanic constructs along open fissures in many terrestrial volcanic fields. Assuming a volcanic origin, the dome-lineament relationship suggests localized, structurally-controlled eruptions along open fissures. Initial extension caused the opening of fractures, which was followed by localized extrusions. Such localized development can provide information about eruption rates, magma compositions, or the physical properties of erupted lava. Either during or after volcanic activity, continued extension led to several domes being dissected by fissures.

  19. Full Dome Development for Interactive Immersive Training Capabilities

    Science.gov (United States)

    2015-04-03

    called the the vDome Player. This application serves as a familiar user interface for direct media playback. Modeled after the widely used VLC ...charrette challenge to task. Below are my notes on where everyone is in planning thei r f inal proj ects . Please let me know (comments or emai l...space with a lot of sound and feeling. What is challenging ? The challenge is how to get depth of field in the dome. Trying to gently allure people into

  20. Susceptibility of lava domes to erosion and collapse by toppling on cooling joints

    Science.gov (United States)

    Smith, John V.

    2018-01-01

    The shape of lava domes typically leads to the formation of radial patterns of cooling joints. These cooling joints define the orientation of the columnar blocks which plunge toward the center of the dome. In the lower parts of the dome the columns plunge into the dome at low angles and are relatively stable. Higher in the dome the columns plunge into the dome at steep angles. These steeply plunging columns are susceptible to toppling and, if the lower part of a dome is partially removed by erosion or collapse, the unstable part of the dome becomes exposed leading to toppling failure. Examples of this process are provided from coastal erosion of lava domes at Katsura Island, Shimane Peninsula, western Japan. An analogue model is presented to demonstrate the mechanism. It is proposed that the mechanism can contribute to collapse of lava domes during or after emplacement.

  1. Kinetic simulations of Rayleigh-Taylor instabilities

    International Nuclear Information System (INIS)

    Sagert, Irina; Bauer, Wolfgang; Colbry, Dirk; Howell, Jim; Staber, Alec; Strother, Terrance

    2014-01-01

    We report on an ongoing project to develop a large scale Direct Simulation Monte Carlo code. The code is primarily aimed towards applications in astrophysics such as simulations of core-collapse supernovae. It has been tested on shock wave phenomena in the continuum limit and for matter out of equilibrium. In the current work we focus on the study of fluid instabilities. Like shock waves these are routinely used as test-cases for hydrodynamic codes and are discussed to play an important role in the explosion mechanism of core-collapse supernovae. As a first test we study the evolution of a single-mode Rayleigh-Taylor instability at the interface of a light and a heavy fluid in the presence of a gravitational acceleration. To suppress small-wavelength instabilities caused by the irregularity in the separation layer we use a large particle mean free path. The latter leads to the development of a diffusion layer as particles propagate from one fluid into the other. For small amplitudes, when the instability is in the linear regime, we compare its position and shape to the analytic prediction. Despite the broadening of the fluid interface we see a good agreement with the analytic solution. At later times we observe the development of a mushroom like shape caused by secondary Kelvin-Helmholtz instabilities as seen in hydrodynamic simulations and consistent with experimental observations.

  2. Slavnov-Taylor identities for primordial perturbations

    International Nuclear Information System (INIS)

    Berezhiani, Lasha; Khoury, Justin

    2014-01-01

    Correlation functions of adiabatic modes in cosmology are constrained by an infinite number of consistency relations, which relate N + 1-point correlation functions with a soft-momentum scalar or tensor mode to a symmetry transformation on N-point correlation functions of hard-momentum modes. They constrain, at each order n, the q n behavior of the soft limits. In this paper we show that all consistency relations derive from a single, master identity, which follows from the Slavnov-Taylor identity for spatial diffeomorphisms. This master identity is valid at any value of q and therefore goes beyond the soft limit. By differentiating it n times with respect to the soft momentum, we recover the consistency relations at each q order. Our approach underscores the role of spatial diffeomorphism invariance at the root of cosmological consistency relations. It also offers new insights on the necessary conditions for their validity: a physical contribution to the vertex functional must satisfy certain analyticity properties in the soft limit in order for the consistency relations to hold. For standard inflationary models, this is equivalent to requiring that mode functions have constant growing-mode solutions. For more exotic models in which modes do not ''freeze'' in the usual sense, the analyticity requirement offers an unambiguous criterion

  3. Manipulating Rayleigh-Taylor Growth Using Adjoints

    Science.gov (United States)

    Kord, Ali; Capecelatro, Jesse

    2017-11-01

    It has been observed that initial interfacial perturbations affect the growth of Rayleigh-Taylor (RT) instabilities. However, it remains to be seen to what extent the perturbations alter the RT growth rate. Direct numerical simulations (DNS) provide a powerful means for studying the effects of initial conditions (IC) on the growth rate. However, a brute-force approach for identifying optimal initial perturbations is not practical via DNS. In addition, identifying sensitivity of the RT growth to the large number of parameters used in defining the IC is computationally expensive. A discrete adjoint is formulated to measure sensitivities of multi-mode RT growth to ICs in a high-order finite difference framework. The sensitivity is used as a search direction for adjusting the initial perturbations to both maximize and suppress the RT growth rate during its non-linear regime. The modes that contribute the greatest sensitivity are identified, and optimized perturbation energy spectrum are reported. PhD Student, Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI.

  4. Geological evolution of the Afro-Arabian dome

    Science.gov (United States)

    Almond, D. C.

    1986-12-01

    The Afro-Arabian dome includes the elevated continental regions enclosing the Red Sea, Gulf of Aden, and the Ethiopian rift system, and extends northwards as far as Jordan. It is more than an order of magnitude larger than other African uplifts. Both the structures and the igneous rocks of the dome appear to be products of the superimposition of two, perhaps three, semi-independent generating systems, initiated at different times but all still active. A strain pattern dominated by NW-trending basins and rifts first became established early in the Cretaceous. By the end of the Oligocene, much of the extensional strain had been taken up along the Red Sea and Gulf of Aden axes, which subsequently developed into an ocean. Palaeogene "trap" volcanism of mildly alkaline to transitional character was related to this horizontal extension rather than to doming. Further west, the East Sahara swell has a history of intermittent alkaline volcanicity which began in the Mesozoic and was independent of magmatism in the Afro-Arabian dome. Volcanicity specifically related to doming began in the Miocene along a N-S zone of uplift extending from Ethiopia to Syria. This elongated swell forms the northern termination of the East African system of domes and rifts, characterized by episodic vertical uplift but very little extension. Superimposition of epeirogenic uplift upon structures formed by horizontal extension took place in the Neogene. Volcanicity related to vertical tectonics is mildly alkaline in character, whereas transitional and tholeiitic magmas are found along the spreading axes.

  5. Observer Kalman Filter Identification of Suspen-Dome

    Directory of Open Access Journals (Sweden)

    Guojun Sun

    2017-01-01

    Full Text Available A number of Suspen-Dome structures have been built, but there is some difficulty in using experimental data to obtain good modal parameters, especially modal damping. In this paper, an ANSYS numerical simulation of the 35.4 m span Suspen-Dome is presented. Firstly, the natural vibration characteristics of Suspen-Dome and dynamic response under some random forces were obtained. Then the results of the numerical simulation established that 60 modes are sufficient for a reasonable dynamic model. This model is used to represent the Suspen-Dome dynamic behavior, and OKID is then used to try to identify a model from simulated data. A 400-order model generated from OKID is shown to contain the 60 modes from ANSYS and is shown to give good predictions of the dynamic behavior of Suspen-Dome. The results of this paper can confirm that it can be a very efficient tool for the identification of models of Suspen-Dome dynamics.

  6. Halogen species record Antarctic sea ice extent over glacial–interglacial periods

    Directory of Open Access Journals (Sweden)

    A. Spolaor

    2013-07-01

    Full Text Available Sea ice is an integral part of the earth's climate system because it affects planetary albedo, sea-surface salinity, and the atmosphere–ocean exchange of reactive gases and aerosols. Bromine and iodine chemistry is active at polar sea ice margins with the occurrence of bromine explosions and the biological production of organoiodine from sea ice algae. Satellite measurements demonstrate that concentrations of bromine oxide (BrO and iodine oxide (IO decrease over sea ice toward the Antarctic interior. Here we present speciation measurements of bromine and iodine in the TALDICE (TALos Dome Ice CorE ice core (159°11' E, 72°49' S; 2315 m a.s.l. spanning the last 215 ky. The Talos Dome ice core is located 250 km inland and is sensitive to marine air masses intruding onto the Antarctic Plateau. Talos Dome bromide (Br− is positively correlated with temperature and negatively correlated with sodium (Na. Based on the Br−/Na seawater ratio, bromide is depleted in the ice during glacial periods and enriched during interglacial periods. Total iodine, consisting of iodide (I− and iodate (IO3−, peaks during glacials with lower values during interglacial periods. Although IO3− is considered the most stable iodine species in the atmosphere it was only observed in the TALDICE record during glacial maxima. Sea ice dynamics are arguably the primary driver of halogen fluxes over glacial–interglacial timescales, by altering the distance between the sea ice edge and the Antarctic plateau and by altering the surface area of sea ice available to algal colonization. Based on our results we propose the use of both halogens for examining Antarctic variability of past sea ice extent.

  7. The Rayleigh-Taylor instability in the spherical pinch

    International Nuclear Information System (INIS)

    Chen, H.B.; Hilko, B.; Panarella, E.

    1994-01-01

    The spherical pinch (SP) concept is an outgrowth of the inertial confinement model (ICF). Unlike the ICF where instabilities, especially the Rayleigh-Taylor instability, have been studied extensively, the instability study of the spherical pinch has just begun. The Raleigh-Taylor instability is investigated for the first time in the SP in the present work. By using the simple condition for the Rayleigh-Taylor instability ∇p · ∇p < O (density and pressure gradients have opposite direction), we have qualitatively identified the regions for development of instabilities in the SP. It is found that the explosion phase (central discharge) is stable and instabilities take place in the imploding phase. However, the growth rate for the instability is not in exponential form, and the appearance of the Rayleigh-Taylor instability does not prevent the main shock wave from converging to the center of the sphere

  8. Techniques for optimizing nanotips derived from frozen taylor cones

    Science.gov (United States)

    Hirsch, Gregory

    2017-12-05

    Optimization techniques are disclosed for producing sharp and stable tips/nanotips relying on liquid Taylor cones created from electrically conductive materials with high melting points. A wire substrate of such a material with a preform end in the shape of a regular or concave cone, is first melted with a focused laser beam. Under the influence of a high positive potential, a Taylor cone in a liquid/molten state is formed at that end. The cone is then quenched upon cessation of the laser power, thus freezing the Taylor cone. The tip of the frozen Taylor cone is reheated by the laser to allow its precise localized melting and shaping. Tips thus obtained yield desirable end-forms suitable as electron field emission sources for a variety of applications. In-situ regeneration of the tip is readily accomplished. These tips can also be employed as regenerable bright ion sources using field ionization/desorption of introduced chemical species.

  9. A design of inverse Taylor projectiles using material simulation

    International Nuclear Information System (INIS)

    Tonks, Michael; Harstad, Eric; Maudlin, Paul; Trujillo, Carl

    2008-01-01

    The classic Taylor cylinder test, in which a right circular cylinder is projected at a rigid anvil, exploits the inertia of the projectile to access strain rates that are difficult to achieve with more traditional uniaxial testing methods. In this work we present our efforts to design inverse Taylor projectiles, in which a tapered projectile becomes a right circular cylinder after impact, from annealed copper and show that the self-correcting geometry leads to a uniform compressive strain in the radial direction. We design projectiles using finite element simulation and optimization that deform as desired in tests with minor deviations in the deformed geometry due to manufacturing error and uncertainty in the initial velocity. The inverse Taylor projectiles designed in this manner provide a simple means of validating constitutive models. This work is a step towards developing a general method of designing Taylor projectiles that provide stress–strain behavior relevant to particular engineering problems

  10. Rayleigh-Taylor instability and mixing in SN 1987A

    International Nuclear Information System (INIS)

    Ebisuzaki, T.; Shigeyama, T.; Nomoto, K.

    1989-01-01

    The stability of the supernova ejecta is compared with the Rayleigh-Taylor instability for a realistic model of SN 1987A. A linear analysis indicates that the layers around the composition interface between the hydrogen-rich and helium zones, and become Rayleigh-Taylor unstable between the helium and metal zones. In these layers, the pressure increases outward because of deceleration due to the reverse shock which forms when the blast shock hits the massive hydrogen-rich envelope. On the contrary, the density steeply decreases outward because of the preexisting nuclear burning shell. Then, these layers undergo the Raleigh-Taylor instability because of the opposite signs of the pressure and density gradients. The estimated growth rate is larger than the expansion rate of the supernova. The Rayleigh-Taylor instability near the composition interface is likely to induce mixing, which has been strongly suggested from observations of SN 1987A. 25 refs

  11. Himalayan gneiss dome formation in the middle crust and exhumation by normal faulting: New geochronology of Gianbul dome, northwestern India

    Science.gov (United States)

    Horton, Forrest; Lee, Jeffrey; Hacker, Bradley; Bowman-Kamaha'o, Meilani; Cosca, Michael A.

    2015-01-01

    A general lack of consensus about the origin of Himalayan gneiss domes hinders accurate thermomechanical modeling of the orogen. To test whether doming resulted from tectonic contraction (e.g., thrust duplex formation, antiformal bending above a thrust ramp, etc.), channel flow, or via the buoyant rise of anatectic melts, this study investigates the depth and timing of doming processes for Gianbul dome in the western Himalaya. The dome is composed of Greater Himalayan Sequence migmatite, Paleozoic orthogneiss, and metasedimentary rock cut by multiple generations of leucogranite dikes. These rocks record a major penetrative D2 deformational event characterized by a domed foliation and associated NE-SW–trending stretching lineation, and they are flanked by the top-down-to-the-SW (normal-sense) Khanjar shear zone and the top-down-to-the-NE (normal sense) Zanskar shear zone (the western equivalent of the South Tibetan detachment system). Monazite U/Th-Pb geochronology records (1) Paleozoic emplacement of the Kade orthogneiss and associated granite dikes; (2) prograde Barrovian metamorphism from 37 to 33 Ma; (3) doming driven by upper-crustal extension and positive buoyancy of decompression melts between 26 and 22 Ma; and (4) the injection of anatectic melts into the upper levels of the dome—neutralizing the effects of melt buoyancy and potentially adding strength to the host rock—by ca. 22.6 Ma on the southwestern flank and ca. 21 Ma on the northeastern flank. As shown by a northeastward decrease in 40Ar/39Ar muscovite dates from 22.4 to 20.2 Ma, ductile normal-sense displacement within the Zanskar shear zone ended by ca. 22 Ma, after which the Gianbul dome was exhumed as part of a rigid footwall block below the brittle Zanskar normal fault, tilting an estimated 5°–10°SW into its present orientation.

  12. An algorithm for symplectic implicit Taylor-map tracking

    International Nuclear Information System (INIS)

    Yan, Y.; Channell, P.; Syphers, M.

    1992-10-01

    An algorithm has been developed for converting an ''order-by-order symplectic'' Taylor map that is truncated to an arbitrary order (thus not exactly symplectic) into a Courant-Snyder matrix and a symplectic implicit Taylor map for symplectic tracking. This algorithm is implemented using differential algebras, and it is numerically stable and fast. Thus, lifetime charged-particle tracking for large hadron colliders, such as the Superconducting Super Collider, is now made possible

  13. The New Taylorism: Hacking at the Philosophy of the University's End

    Science.gov (United States)

    Goodman, Robin Truth

    2012-01-01

    This article looks at the critical writings of Mark C. Taylor. It suggests that Mark C. Taylor is rewriting a global imaginary devoid of the kind of citizenship that Henry Giroux claims as the basis for public education. Instead, Taylor wants to see the university take shape as profit-generating. According to Taylor, in lieu of learning to take…

  14. On truncated Taylor series and the position of their spurious zeros

    DEFF Research Database (Denmark)

    Christiansen, Søren; Madsen, Per A.

    2006-01-01

    A truncated Taylor series, or a Taylor polynomial, which may appear when treating the motion of gravity water waves, is obtained by truncating an infinite Taylor series for a complex, analytical function. For such a polynomial the position of the complex zeros is considered in case the Taylor...

  15. 76 FR 3570 - Proposed Amendment of Class E Airspace; Taylor, AZ

    Science.gov (United States)

    2011-01-20

    ...-1189; Airspace Docket No. 10-AWP-19] Proposed Amendment of Class E Airspace; Taylor, AZ AGENCY: Federal... proposes to modify Class E airspace at Taylor Airport, Taylor, AZ. Controlled airspace is necessary to accommodate aircraft using the CAMBO One Departure Area Navigation (RNAV) out of Taylor Airport. The FAA is...

  16. The Life and Legacy of G. I. Taylor

    Science.gov (United States)

    Batchelor, G. K.

    1996-07-01

    G.I. Taylor, one of the most distinguished physical scientists of this century, used his deep insight and originality to increase our understanding of phenomena such as the turbulent flow of fluids. His interest in the science of fluid flow was not confined to theory; he was one of the early pioneers of aeronautics, and designed a new type of anchor that was inspired by his passion for sailing. Taylor spent most of his working life in the Cavendish Laboratory in Cambridge, where he investigated the mechanics of fluid and solid materials; his discoveries and ideas have had application throughout mechanical, civil, and chemical engineering, meteorology, oceanography and materials science. He was also a noted research leader, and his group in Cambridge became one of the most productive centers for the study of fluid mechanics. How was Taylor able to be innovative in so many different ways? This interesting and unusual biography helps answer that question. Professor Batchelor, himself a student and close collaborator of Taylor, is ideally placed to describe Taylor's life, achievements and background. He does so without introducing any mathematical details, making this book enjoyable reading for a wide range of people--and especially those whose own interests have brought them into contact with the legacy of Taylor.

  17. Experiments on the Taylor system with an axial flow

    International Nuclear Information System (INIS)

    Tsameret, Avraham.

    1993-02-01

    This work is an experimental study of the Taylor system with a superimposed axial flow. The convective and absolute instability lines which are associated with the propagating Taylor vortices are measured. A quantitative agreement is found with the theoretical predictions. Noise-sustained structures are found to exist in the convectively unstable region, above a critical value of the through flow. These structures are propagating Taylor vortices that are characterized by a noisy power spectrum and irregular temporal dynamics of velocity amplitude. At the absolute instability line the power spectrum of the propagating Taylor vortices exhibits transition to a sharp peak, and the amplitude of the propagating Taylor vortices becomes stationary. The mechanism that generates the noise-sustained structures is identified with a process of permanent amplification of noise that is generated mainly near the inlet boundary. The intrinsic noise in the system is studied. This study is motivated by the question of whether the noise which generates the noise-sustained structures is thermal. The intensity of the intrinsic noise is estimated by several methods, which includes a comparison of data with numerical simulations of the amplitude equation with a noise term. It is found that the intrinsic noise is not thermal, although its intensity reaches the thermal noise level at small through-flow velocities. Novel states are manifested in the system as a result of interaction between the propagating Taylor vortices and spiral modes. These states are studied and their spatial and temporal properties are analyzed. (author)

  18. Dynamic response of domes in CANDU 600 MWe containments

    International Nuclear Information System (INIS)

    Aziz, T.S.; Meng, V.; Alizadeh, A.

    1981-01-01

    CANDU reactors of the 600 MWe type are typically housed in a cylindrical prestressed concrete containment structure; rising from a flat slab and ending in a domed roof. The principal components of this structure are: (a) a circular base slab, (b) a vertical cylinder and (c) a spherical dome cap. A unique feature of a CANDU 600 MWe containment structure is the existence of an inner spherical concrete dome, located below the outer spherical dome, which serves as the bottom of a reservoir for the storage of 560,000 imperial gallons of douzing water. The thickness of the prestressed cylinder wall is approximately doubled between the two domes to create a ring beam. Inside the containment there exists an internal concrete structure which is independent of the containment structure except for support on the base slab. The containment boundary is a fully prestressed concrete structure. This paper deals with the seismic behaviour of the CANDU 600 MWe containment structure and the effect of its unique features; such as the lower dome and the douzing water on this behaviour. The objective of the study is to evaluate the interaction (coupling) effects between the different components of the structure. The approach taken is to study each component of the structure individually, then an assembly of the different components, and finally the total containment structure. This presentation is limited to the vertical response of the structure under a vertical earthquake only. Axisymmetric finite elements were used in all models. The vertical responses at selected points of the structure were obtained by the response spectrum method as well as the time-history method. It was observed that the response spectrum method over-estimates the vertical response of the domes and under-estimates the vertical responses of the ring girder and the containment cylinder compared to the time-history method. (orig./RW)

  19. Weather and forecasting at Wilkins ice runway, Antarctica

    International Nuclear Information System (INIS)

    Carpentier, Scott

    2010-01-01

    Aviation forecasts for Wilkins ice runway in East Antarctica are developed within the conceptual framework of flow against a single dome shaped hill. Forecast challenges include the sudden onset of blizzards associated with the formation of an internal gravity wave; frontal weather; transient wake vortices and mesoscale lows; temperature limitations on runway use; and snow and fog events. These key weather aspects are presented within the context of synoptic to local scale climatologies and numerical weather prediction models.

  20. Magma Dynamics in Dome-Building Volcanoes

    Science.gov (United States)

    Kendrick, J. E.; Lavallée, Y.; Hornby, A. J.; Schaefer, L. N.; Oommen, T.; Di Toro, G.; Hirose, T.

    2014-12-01

    The frequent and, as yet, unpredictable transition from effusive to explosive volcanic behaviour is common to active composite volcanoes, yet our understanding of the processes which control this evolution is poor. The rheology of magma, dictated by its composition, porosity and crystal content, is integral to eruption behaviour and during ascent magma behaves in an increasingly rock-like manner. This behaviour, on short timescales in the upper conduit, provides exceptionally dynamic conditions that favour strain localisation and failure. Seismicity released by this process can be mimicked by damage accumulation that releases acoustic signals on the laboratory scale, showing that the failure of magma is intrinsically strain-rate dependent. This character aids the development of shear zones in the conduit, which commonly fracture seismogenically, producing fault surfaces that control the last hundreds of meters of ascent by frictional slip. High-velocity rotary shear (HVR) experiments demonstrate that at ambient temperatures, gouge behaves according to Byerlee's rule at low slip velocities. At rock-rock interfaces, mechanical work induces comminution of asperities and heating which, if sufficient, may induce melting and formation of pseudotachylyte. The viscosity of the melt, so generated, controls the subsequent lubrication or resistance to slip along the fault plane thanks to non-Newtonian suspension rheology. The bulk composition, mineralogy and glass content of the magma all influence frictional behaviour, which supersedes buoyancy as the controlling factor in magma ascent. In the conduit of dome-building volcanoes, the fracture and slip processes are further complicated: slip-rate along the conduit margin fluctuates. The shear-thinning frictional melt yields a tendency for extremely unstable slip thanks to its pivotal position with regard to the glass transition. This thermo-kinetic transition bestows the viscoelastic melt with the ability to either flow or

  1. Geologic study of the interior Salt Domes of Northeast Texas Salt-Dome basin to investigate their suitability for possible storage of radioactive waste material

    International Nuclear Information System (INIS)

    1976-05-01

    The purpose of this study was to investigate the movement and hydrologic stability of the domes, to identify the domes which appear suitable for further study and consideration, and to outline the additional information needed to evaluate these domes. The growth of the interior salt domes appears to have slowed with geologic time and to have halted altogether. The Bullard, Whitehouse, and Keechi domes probably are not subject to significant dissolution at the present time. However, caprock found at Bullard and Whitehouse indicates that salt dissolution occurred at some period during the past 50 million years since Wilcox was deposited. It is recommended that shallow water wells be drilled and tested

  2. 33 CFR 207.170d - Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Taylor Creek, navigation lock (S-193) across the entrance to Taylor Creek at Lake Okeechobee, Okeechobee, Fla.; use, administration..., DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.170d Taylor Creek, navigation lock...

  3. Man in the Arctic, The Changing Nature of His Quest for Food and Water as Related to Snow, Ice, and Permafrost

    Science.gov (United States)

    1962-01-01

    the general dura - tion of freshwater ice approaches ten months, al- though occasionally ice remains in some of the larger lakes throughout the... Marguerite G. "Marooned in the clouds," Atlantic Monthly, CLXXXI, no. 2 (j948), 34-46. Taylor, Andrew. "Snow compaction." SIPRE Report 13 (1953), pp. xxiv

  4. Synchronisation of the EDML and EDC ice cores for the last 52 kyr by volcanic signature matching

    DEFF Research Database (Denmark)

    Severi, M.; Becagli, S.; Castellano, E.

    2007-01-01

    stratigraphic link between EDML and EDC, which was dated by a simpler 1D ice-flow model. The synchronisation between the two EPICA ice cores was done through the identification of several common volcanic signatures. This paper describes the rigorous method, using the signature of volcanic sulfate, which...... to find out which of the models is affected by errors, but assuming that the thinning function at both sites and accumulation history at Dome C (which was drilled on a dome) are correct, this anomaly can be ascribed to a complex spatial accumulation variability (which may be different in the past compared...

  5. An assessment of hydrothermal alteration in the Santiaguito lava dome complex, Guatemala: implications for dome collapse hazards

    Science.gov (United States)

    Ball, Jessica L.; Calder, Eliza S.; Hubbard, Bernard E.; Bernstein, Marc L.

    2013-01-01

    A combination of field mapping, geochemistry, and remote sensing methods has been employed to determine the extent of hydrothermal alteration and assess the potential for failure at the Santiaguito lava dome complex, Guatemala. The 90-year-old complex of four lava domes has only experienced relatively small and infrequent dome collapses in the past, which were associated with lava extrusion. However, existing evidence of an active hydrothermal system coupled with intense seasonal precipitation also presents ideal conditions for instability related to weakened clay-rich edifice rocks. Mapping of the Santiaguito dome complex identified structural features related to dome growth dynamics, potential areas of weakness related to erosion, and locations of fumarole fields. X-ray diffraction and backscattered electron images taken with scanning electron microscopy of dacite and ash samples collected from around fumaroles revealed only minor clay films, and little evidence of alteration. Mineral mapping using ASTER and Hyperion satellite images, however, suggest low-temperature (<150 °C) silicic alteration on erosional surfaces of the domes, but not the type of pervasive acid-sulfate alteration implicated in collapses of other altered edifices. To evaluate the possibility of internal alteration, we re-examined existing aqueous geochemical data from dome-fed hot springs. The data indicate significant water–rock interaction, but the Na–Mg–K geoindicator suggests only a short water residence time, and δ18O/δD ratios show only minor shifts from the meteoric water line with little precipitation of secondary (alteration) minerals. Based on available data, hydrothermal alteration on the dome complex appears to be restricted to surficial deposits of hydrous silica, but the study has highlighted, importantly, that the 1902 eruption crater headwall of Santa María does show more advanced argillic alteration. We also cannot rule out the possibility of advanced alteration

  6. Dome-shaped PDC cutters drill harder rock effectively

    International Nuclear Information System (INIS)

    Moran, D.P.

    1992-01-01

    This paper reports that rock mechanics and sonic travel time log data indicate that bits with convex-shaped polycrystalline diamond compact (PDC) cutters can drill harder rock formations than comparable bits with flat PDC cutters. The Dome-shaped cutters have drilled carbonate formations with sonic travel times as small as 50 μsec/ft, compared to the standard cutoff of 75 μsec/ft for flat PCD cutters. Recent field data from slim hole wells drilled in the Permian basin have shown successful applications of the 3/8-in. Dome cutter in the Grayburg dolomite with its sonic travel times as low as 50-55 μsec/ft and compressive strengths significantly greater than the standard operating range for PDC bit applications. These field data indicate that the Dome cutters can successfully drill hard rock. The convex cutter shape as good impact resistance, cuttings removal, heat dissipation, and wear resistance

  7. High-resolution seismic reflection study, Vacherie Dome

    International Nuclear Information System (INIS)

    1984-06-01

    A high-resolution seismic reflection study, consisting of recording, processing, and interpreting four seismic reflection lines, was made at Vacherie Dome, Louisiana. The presumed shape of the dome, as pictured in the geologic area characterization report by Law Engineering Testing Company in 1982, was based largely on interpretation of gravity data, constrained by a few wells and exploration-type seismic profiles. The purpose of the study was to obtain refined profiles of the dome above -914 m (-3000 ft) elevation. Additional study had been recommended by Louisiana State University in 1967 and the Office of Nuclear Waste Isolation in 1981 because the interpreted size of Vacherie Dome was based on limited seismic and gravity data. Forty-eight traces of seismic data were recorded each time shots were made to generate energy. Twelve-fold, common-depth-point data were obtained using geophone stations spaced at 15-m (50-ft) intervals with shots at 30-m (100-ft) intervals. The time-sampling interval used was 1 ms. Processing intended to enhance resolution included iterative static corrections, deconvolution before stacking, and both time- and depth-migration. The locations of the steep dome sides were inferred primarily from terminations of strong reflections (migrated) from strata near the top of the upper and lower Cretaceous sections. This interpretation agrees closely with the presumed shape from the top of the dome to about -610 m (-2000 ft) elevation, but below this on three of the profiles, this interpretation indicates a steeper salt face than the presumed shape. The area reduction at -914 m (-3000 ft) elevation is estimated to be on the order of 20 percent. 10 references, 11 figures, 4 tables

  8. Toward an integrated ice core chronology using relative and orbital tie-points

    Science.gov (United States)

    Bazin, L.; Landais, A.; Lemieux-Dudon, B.; Toyé Mahamadou Kele, H.; Blunier, T.; Capron, E.; Chappellaz, J.; Fischer, H.; Leuenberger, M.; Lipenkov, V.; Loutre, M.-F.; Martinerie, P.; Parrenin, F.; Prié, F.; Raynaud, D.; Veres, D.; Wolff, E.

    2012-04-01

    Precise ice cores chronologies are essential to better understand the mechanisms linking climate change to orbital and greenhouse gases concentration forcing. A tool for ice core dating (DATICE [developed by Lemieux-Dudon et al., 2010] permits to generate a common time-scale integrating relative and absolute dating constraints on different ice cores, using an inverse method. Nevertheless, this method has only been applied for a 4-ice cores scenario and for the 0-50 kyr time period. Here, we present the bases for an extension of this work back to 800 ka using (1) a compilation of published and new relative and orbital tie-points obtained from measurements of air trapped in ice cores and (2) an adaptation of the DATICE inputs to 5 ice cores for the last 800 ka. We first present new measurements of δ18Oatm and δO2/N2 on the Talos Dome and EPICA Dome C (EDC) ice cores with a particular focus on Marine Isotopic Stages (MIS) 5, and 11. Then, we show two tie-points compilations. The first one is based on new and published CH4 and δ18Oatm measurements on 5 ice cores (NorthGRIP, EPICA Dronning Maud Land, EDC, Talos Dome and Vostok) in order to produce a table of relative gas tie-points over the last 400 ka. The second one is based on new and published records of δO2/N2, δ18Oatm and air content to provide a table of orbital tie-points over the last 800 ka. Finally, we integrate the different dating constraints presented above in the DATICE tool adapted to 5 ice cores to cover the last 800 ka and show how these constraints compare with the established gas chronologies of each ice core.

  9. Jurassic domes in the North Sea - northern North Atlantic region

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1996-12-31

    The stratigraphic and tectonic evolution of the Jurassic of East Greenland, the Norwegian Shelf and the North Sea is remarkably similar. A major Middle Jurassic unconformity occurs in all three areas. In the North Sea it is commonly termed the `Mid-Cimmerian Unconformity` and is characterized by progressive truncation of the underlying section towards a centre at the triple junction between the Central Graben, Viking Graben and Moray Firth. Strata above the unconformity show a progressive Late Aalenian-Early Kimmeridgian onlap in the same direction. These relations have been interpreted as caused by Early Jurassic uplift and of a major thermal dome in the central North Sea, followed by Medial and Late Jurassic rifting, erosion, deflation and transgression of the dome. The East Greenland unconformity shows progressive truncation of underlying strata from south to north, and Bajocian to Callovian onlap in the same direction. The same pattern seems to be developed on the conjugate Norwegian margin. This suggests the possibility that the three unconformities have similar causes for their development. It is proposed that major rift domes formed in the Central North Sea and in the Greenland-Norway seaway in Early Jurassic times. The domes were eroded and gradually deflated during Medial Jurassic times and were finally submerged by the Late Oxfordian-Kimmeridgian. They were associated with volcanism and rifting which was delayed with respect to dome initiation. Roughly contemperaneous domes were present west of Britain, north of the Porcupine Seabight, and in Scania, southern Sweden, as reflected by development of asymmetrical unconformities showing progressive truncation of underlying strata, onlap of overlying Jurassic strata, and associated intrusive and extrusive volcanism. The domes are related to impingement of the heads of transient mantle plumes at the base of the lithosphere. The associated unconformities are thus of non-eustatic nature. Domal uplift and

  10. Predictions of Aerodynamic Heating on Tactical Missile Domes

    Science.gov (United States)

    1979-04-25

    A . Martellucci W. Daskin J. D. Cresswell J. B. Arnaiz L. A . Marshall J. Cassanto R. Hobbs C. Harris F. George P.O. Box 8555 Philadelphia, PA J9101... A LEVELs NSWC TR 79-21 i PREDICTIONS OF AERODYNAMIC HEATING ON TACTICAL MISSILE DOMES A wo BY T. F. ZIEN W. C. RAGSDALE RESEARCH TECHNOLOGY...DOMES SAUTHOR( a ) 8. CONTRACT OR GRANT NUMBER() T. F. ZiendW.C jRagsale 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT. TASK

  11. Visual aesthetics study: Gibson Dome area, Paradox Basin, Utah

    International Nuclear Information System (INIS)

    1984-03-01

    The Visual Aesthetics study was performed as an initial assessment of concerns regarding impacts to visual resources that might be associated with the construction of a geologic nuclear waste repository and associated rail routes in the Gibson Dome location of southeastern Utah. Potential impacts to visual resources were evaluated by predicting visibility of the facility and railway routes using the US Forest Service (USFS) computer program, VIEWIT, and by applying the Bureau of Land Management (BLM) Visual Resource Management (VRM) methodology. Five proposed facility sites in the Gibson Dome area and three proposed railway routes were evaluated for visual impact. 10 references, 19 figures, 5 tables

  12. FLAMMABLE GAS DIFFUSION THROUGH SINGLE SHELL TANK (SST) DOMES

    Energy Technology Data Exchange (ETDEWEB)

    MEACHAM, J.E.

    2003-11-10

    This report quantified potential hydrogen diffusion through Hanford Site Single-Shell tank (SST) domes if the SSTs were hypothetically sealed airtight. Results showed that diffusion would keep headspace flammable gas concentrations below the lower flammability limit in the 241-AX and 241-SX SST. The purpose of this document is to quantify the amount of hydrogen that could diffuse through the domes of the SSTs if they were hypothetically sealed airtight. Diffusion is assumed to be the only mechanism available to reduce flammable gas concentrations. The scope of this report is limited to the 149 SSTs.

  13. Compression of an Accelerated Taylor State in SSX

    Science.gov (United States)

    Shrock, J. E.; Suen-Lewis, E. M.; Barbano, L. J.; Kaur, M.; Schaffner, D. A.; Brown, M. R.

    2017-10-01

    In the Swarthmore Spheromak Experiment (SSX), compact toroidal plasmas are launched from a plasma gun and evolve into minimum energy twisted Taylor states. The plumes initially have a velocity 40 km/s, density 0.4 ×1016 cm-3 , and proton temperature 20 eV . After formation, the plumes are accelerated by pulsed pinch coils with rise times τ1 / 4 = (π / 2) √{ LC } less than 1 μ s and currents Ipeak =V0 / Z =V0 /√{ L / C } on the order of 104 A. The accelerated Taylor States are abruptly stagnated in a copper flux conserver, and over the course of t plasma, the other to particle motion parallel to the field. We observe Taylor state compression most in agreement with the parallel equation of state: d / dt (P∥B2 /n3) = 0 . DOE ARPA-E ALPHA Program.

  14. Rayleigh-Taylor instability of cylindrical jets with radial motion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang M. [GE Nuclear, Wilmington, NC (United States); Schrock, V.E.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States)

    1995-09-01

    Rayleigh-Taylor instability of an interface between fluids with different densities subjected to accelleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed.

  15. Photonic arbitrary waveform generator based on Taylor synthesis method

    DEFF Research Database (Denmark)

    Liao, Shasha; Ding, Yunhong; Dong, Jianji

    2016-01-01

    Arbitrary waveform generation has been widely used in optical communication, radar system and many other applications. We propose and experimentally demonstrate a silicon-on-insulator (SOI) on chip optical arbitrary waveform generator, which is based on Taylor synthesis method. In our scheme......, a Gaussian pulse is launched to some cascaded microrings to obtain first-, second- and third-order differentiations. By controlling amplitude and phase of the initial pulse and successive differentiations, we can realize an arbitrary waveform generator according to Taylor expansion. We obtain several typical...... waveforms such as square waveform, triangular waveform, flat-top waveform, sawtooth waveform, Gaussian waveform and so on. Unlike other schemes based on Fourier synthesis or frequency-to-time mapping, our scheme is based on Taylor synthesis method. Our scheme does not require any spectral disperser or large...

  16. Nonlinear saturation of the Rayleigh endash Taylor instability

    International Nuclear Information System (INIS)

    Das, A.; Mahajan, S.; Kaw, P.; Sen, A.; Benkadda, S.; Verga, A.

    1997-01-01

    A detailed numerical simulation of the nonlinear state of the Rayleigh endash Taylor instability has been carried out. There are three distinct phases of evolution where it is governed by the (i) linear effects, (ii) effects arising from the conventional nonlinear terms and (iii) subtle nonlinear effects arising through the coupling terms. During the third phase of evolution, there is a self-consistent generation of shear flow which saturates the Rayleigh endash Taylor instability even in situations (with periodic boundaries) where, in principle, an infinite amount of gravitational energy can be tapped. The Galerkin approximation is presented to provide an understanding of our numerical findings. Last, there is an attempt to provide a comprehensive understanding of the nonlinear state of the Rayleigh endash Taylor instability by comparing and contrasting this work with earlier studies. copyright 1997 American Institute of Physics

  17. Bubble behavior in a vertical Taylor-Couette flow

    International Nuclear Information System (INIS)

    Murai, Y; Oiwa, H; Takeda, Y

    2005-01-01

    Bubble distributions organized in a vertical Taylor-Couette flow are experimentally investigated. Modification of shear stress due to bubbles is measured with a torque sensor installed on the rotating inner cylinder. The wall shear stress decreases as bubbles are injected in all the tested range of Re from 600 to 4500. The drag reduction ratio per void fraction measured in the present experiment, which indicates net gain of the drag reduction, has been evaluated. The gain was more than unity for Re 4000. The maximum gain achieved was around 10 at Re = 600, at which point the bubbles dispersed widely on the inner cylinder surface and effectively restrict momentum exchange of fluid between the two walls. The expansion of Taylor vortices in the vertical direction by the presence of bubbles was confirmed by flow visualization including particle tracking velocimetry. Such bubble behaviours interacting with Taylor vortices are discussed in detail in this paper

  18. On Using Taylor's Hypothesis for Three-Dimensional Mixing Layers

    Science.gov (United States)

    LeBoeuf, Richard L.; Mehta, Rabindra D.

    1995-01-01

    In the present study, errors in using Taylor's hypothesis to transform measurements obtained in a temporal (or phase) frame onto a spatial one were evaluated. For the first time, phase-averaged ('real') spanwise and streamwise vorticity data measured on a three-dimensional grid were compared directly to those obtained using Taylor's hypothesis. The results show that even the qualitative features of the spanwise and streamwise vorticity distributions given by the two techniques can be very different. This is particularly true in the region of the spanwise roller pairing. The phase-averaged spanwise and streamwise peak vorticity levels given by Taylor's hypothesis are typically lower (by up to 40%) compared to the real measurements.

  19. O salário na obra de Frederick Winslow Taylor Frederick Winslow Taylor's oeuvre: an analysis of wages

    Directory of Open Access Journals (Sweden)

    Victor Paulo Gomes da Silva

    2011-08-01

    Full Text Available O presente artigo analisa e explica a perspectiva de Frederick Winslow Taylor sobre o salário, tal como enunciada em suas duas grandes obras: Shop management (1903 e Principles of scientific management (1911. A primeira parte consubstancia-se na apresentação de aspectos econômicos relevantes que caracterizaram o tempo em que ele viveu e o quanto influenciaram suas obras. Na segunda parte, é efetuada uma análise da forma como o salário é apresentado nas duas obras de F. W. Taylor. O artigo termina com um comentário sobre as obras supracitadas no que se refere à perspectiva taylorista do salário.This paper analyses and explains Frederick Winslow Taylor's perspective on wages, as it is presented in his main literary works: Shop management (1903 and Principles of scientific management (1911. The first part presents the main economic aspects that characterized his lifetime, which undoubtedly influenced his literary works. The second part analyses F. W. Taylor's two main books in which the author's perspective about wages is discussed. The paper concludes with a critical view of F. W. Taylor's view on wages.

  20. PREFACE: The 15th International Couette-Taylor Worskhop

    Science.gov (United States)

    Mutabazi, Innocent; Crumeyrolle, Olivier

    2008-07-01

    The 15th International Couette-Taylor Worskhop (ICTW15) was held in Le Havre, France from 9-12 July 2007. This regular international conference started in 1979 in Leeds, UK when the research interest in simple models of fluid flows was revitalized by systematic investigation of Rayleigh-Bénard convection and the Couette-Taylor flow. These two flow systems are good prototypes for the study of the transition to chaos and turbulence in closed flows. The workshop themes have been expanded from the original Couette-Taylor flow to include other centrifugal instabilities (Dean, Görtler, Taylor-Dean), spherical Couette flows, thermal convection instabilities, MHD, nonlinear dynamics and chaos, transition to turbulence, development of numerical and experimental techniques. The impressive longevity of the ICTW is due to the close interaction and fertile exchanges between international research groups from different disciplines: Physics and Astrophysics, Applied Mathematics, Mechanical Engineering, Chemical Engineering. The present workshop was attended by 100 participants, the program included over 83 contributions with 4 plenary lectures, 68 oral communications and 17 posters. The topics include, besides the classical Couette-Taylor flows, the centrifugal flows with longitudinal vortices, the shear flows, the thermal convection in curved geometries, the spherical Couette-Taylor flow, the geophysical flows, the magneto-hydrodynamic effects including the dynamo effect, the complex flows (viscoelasticity, immiscible fluids, bubbles and migration). Selected papers have been processed through the peer review system and are published in this issue of the Journal of Physics: Conference Series. The Workshop has been sponsored by Le Havre University, the Region Council of Haute-Normandie, Le Havre City Council, CNRS (ST2I, GdR-DYCOEC), and the European Space Agency through GEOFLOW program. The French Ministry of Defense (DGA), the Ministry of Foreign Affairs, the Ministry of

  1. Supporting evidence from the EPICA Dronning Maud Land ice core for atmospheric CO2 changes during the past millennium

    International Nuclear Information System (INIS)

    Siegenthaler, Urs; Monnin, Eric; Kawamura, Kenji; Spahni, Renato; Schwander, Jakob; Stauffer, Bernhard; Stocker, Thomas F.; Fischer, Hubertus

    2005-01-01

    The most direct method of investigating past variations of the atmospheric CO 2 concentration before 1958, when continuous direct atmospheric CO 2 measurements started, is the analysis of air extracted from suitable ice cores. Here we present a new detailed CO 2 record from the Dronning Maud Land (DML) ice core, drilled in the framework of the European Project for Ice Coring in Antarctica (EPICA) and some new measurements on a previously drilled ice core from the South Pole. The DML CO 2 record shows an increase from about 278 to 282 parts per million by volume (ppmv) between ad 1000 and ad 1200 and a fairly continuous decrease to a mean value of about 277 ppmv around ad 1700. While the new South Pole measurements agree well with DML at the minimum at ad 1700 they are on average about 2 ppmv lower during the period ad 1000-1500. Published measurements from the coastal high-accumulation site Law Dome are considered as very reliable because of the reproducibility of the measurements, high temporal resolution and an accurate time scale. Other Antarctic ice cores could not, or only partly, reproduce the pre-industrial measurements from Law Dome. A comparison of the trends of DML and Law Dome shows a general agreement. However we should be able to rule out co-variations caused by the same artefact. Two possible effects are discussed, first production of CO 2 by chemical reactions and second diffusion of dissolved air through the ice matrix into the bubbles. While the first effect cannot be totally excluded, comparison of the Law Dome and DML record shows that dissolved air diffusing to bubbles cannot be responsible for the pre-industrial variation. Therefore, the new record is not a proof of the Law Dome results but the first very strong support from an ice core of the Antarctic plateau

  2. Instabilities with polyacrylamide solution in small and large aspect ratios Taylor-Couette systems

    International Nuclear Information System (INIS)

    Smieszek, M; Egbers, C; Crumeyrolle, O; Mutabazi, I

    2008-01-01

    We have investigated the stability of viscoelastic polyacrylamide solution in Taylor-Couette system with different aspect ratios. The first instability modes observed in a Taylor-Couette system with Γ = 10 were TVF and WVF, as for Newtonian fluid. At higher Taylor numbers moving vortices occur, a wavy mode with non-stationary vortex size. In the Taylor-Couette system with Γ = 45.9 we note a coexistence of various instability modes. In addition to TVF, counterpropagating waves developed at the transition from the base state flow. At higher Taylor number values Taylor vortices of different sizes occurred. Reduced amplitude Wavy vortex flow has also been observed.

  3. Prominence Bubble Shear Flows and the Coupled Kelvin-Helmholtz — Rayleigh-Taylor Instability

    Science.gov (United States)

    Berger, Thomas; Hillier, Andrew

    2017-08-01

    Prominence bubbles are large arched structures that rise from below into quiescent prominences, often growing to heights on the order of 10 Mm before going unstable and generating plume upflows. While there is general agreement that emerging flux below pre-existing prominences causes the structures, there is lack of agreement on the nature of the bubbles and the cause of the instability flows. One hypothesis is that the bubbles contain coronal temperature plasma and rise into the prominence above due to both magnetic and thermal buoyancy, eventually breaking down via a magnetic Rayleigh-Taylor (RT) instability to release hot plasma and magnetic flux and helicity into the overlying coronal flux rope. Another posits that the bubbles are actually just “arcades” in the prominence indicating a magnetic separator line between the bipole and the prominence fields with the observed upflows and downflows caused by reconnection along the separator. We analyze Hinode/SOT, SDO/AIA, and IRIS observations of prominence bubbles, focusing on characteristics of the bubble boundary layers that may discriminate between the two hypotheses. We find speeds on the order of 10 km/s in prominence plasma downflows and lateral shear flows along the bubble boundary. Inflows to the boundary gradually increase the thickness and brightness of the layer until plasma drains from there, apparently around the dome-like bubble domain. In one case, shear flow across the bubble boundary develops Kelvin-Helmholtz (KH) vortices that we use to infer flow speeds in the low-density bubble on the order of 100 km/sec. IRIS spectra indicate that plasma flows on the bubble boundary at transition region temperatures achieve Doppler speeds on the order of 50 km/s, consistent with this inference. Combined magnetic KH-RT instability analysis leads to flux density estimates of 10 G with a field angle of 30° to the prominence, consistent with vector magnetic field measurements. In contrast, we find no evidence

  4. Mud dome, stone dome and mud and stone dome in the rural buildings of vernacular architecture in center of Castilla y León (Spain

    Directory of Open Access Journals (Sweden)

    O. Abril Revuelta

    2017-06-01

    Full Text Available In the center of Castilla y León there are few examples of old rural buildings linked to economic activities that have developed in the agrarian field. These are known chozos and casetas, and they have been built with dome-shaped solutions using autochthon materials: mud and stone. The influence of traditional techniques of both elements has generated a singular typological rarely seen in the rest of the Iberian Peninsula. Different types of domes have been analyzed in situ. And they have been contrasted by documentary sources and it has significantly expanded the information published of them, especially about their typological variety and their construction process. This research aims to provide tools to restore a constructive knowledge that is forgotten in place, to value its architectural wealth, which can encourage their rehabilitation.

  5. Numerical simulation of Rayleigh-Taylor turbulent mixing layers

    International Nuclear Information System (INIS)

    Poujade, O.; Lardjane, N.; Peybernes, M.; Boulet, M.

    2009-01-01

    Accelerations in actual Rayleigh-Taylor instabilities are often variable. This article focuses on a particular class of variable accelerations where g(t) ∝ t n . A reference database is built from high resolution hydrodynamic numerical simulations. The successful comparison with a simple OD analytical model and the statistical 2SFK (2-Structure, 2-Fluid, 2-Turbulence) turbulence model is provided. Moreover, we show the difference between the mechanism at play in the Rayleigh-Taylor turbulent mixing zone and Kolmogorov's in the self similar developed turbulent regime. (authors)

  6. Student understanding of Taylor series expansions in statistical mechanics

    Directory of Open Access Journals (Sweden)

    Trevor I. Smith

    2013-08-01

    Full Text Available One goal of physics instruction is to have students learn to make physical meaning of specific mathematical expressions, concepts, and procedures in different physical settings. As part of research investigating student learning in statistical physics, we are developing curriculum materials that guide students through a derivation of the Boltzmann factor using a Taylor series expansion of entropy. Using results from written surveys, classroom observations, and both individual think-aloud and teaching interviews, we present evidence that many students can recognize and interpret series expansions, but they often lack fluency in creating and using a Taylor series appropriately, despite previous exposures in both calculus and physics courses.

  7. Student understanding of Taylor series expansions in statistical mechanics

    Science.gov (United States)

    Smith, Trevor I.; Thompson, John R.; Mountcastle, Donald B.

    2013-12-01

    One goal of physics instruction is to have students learn to make physical meaning of specific mathematical expressions, concepts, and procedures in different physical settings. As part of research investigating student learning in statistical physics, we are developing curriculum materials that guide students through a derivation of the Boltzmann factor using a Taylor series expansion of entropy. Using results from written surveys, classroom observations, and both individual think-aloud and teaching interviews, we present evidence that many students can recognize and interpret series expansions, but they often lack fluency in creating and using a Taylor series appropriately, despite previous exposures in both calculus and physics courses.

  8. Application of the Asymptotic Taylor Expansion Method to Bistable Potentials

    Directory of Open Access Journals (Sweden)

    Okan Ozer

    2013-01-01

    Full Text Available A recent method called asymptotic Taylor expansion (ATEM is applied to determine the analytical expression for eigenfunctions and numerical results for eigenvalues of the Schrödinger equation for the bistable potentials. Optimal truncation of the Taylor series gives a best possible analytical expression for eigenfunctions and numerical results for eigenvalues. It is shown that the results are obtained by a simple algorithm constructed for a computer system using symbolic or numerical calculation. It is observed that ATEM produces excellent results consistent with the existing literature.

  9. Contexto y pensamiento de Charles Taylor sobre el consenso

    Directory of Open Access Journals (Sweden)

    Doris Elena Ospina Muñoz

    2017-01-01

    Full Text Available El artículo sostiene que el consenso no es un tema de primer orden en la filosofía política de Charles Taylor, pero una lectura orientada al problema puede ofrecer los elementos para establecer una teoría sobre dicha noción e identificar los argumentos para su justificación. Además, se enfatiza en el contexto de discusión que permite introducir la filosofía de Taylor como un modo de pensar sobre el consenso, alternativo al constructivismo.

  10. Rapid Calculation of Spacecraft Trajectories Using Efficient Taylor Series Integration

    Science.gov (United States)

    Scott, James R.; Martini, Michael C.

    2011-01-01

    A variable-order, variable-step Taylor series integration algorithm was implemented in NASA Glenn's SNAP (Spacecraft N-body Analysis Program) code. SNAP is a high-fidelity trajectory propagation program that can propagate the trajectory of a spacecraft about virtually any body in the solar system. The Taylor series algorithm's very high order accuracy and excellent stability properties lead to large reductions in computer time relative to the code's existing 8th order Runge-Kutta scheme. Head-to-head comparison on near-Earth, lunar, Mars, and Europa missions showed that Taylor series integration is 15.8 times faster than Runge- Kutta on average, and is more accurate. These speedups were obtained for calculations involving central body, other body, thrust, and drag forces. Similar speedups have been obtained for calculations that include J2 spherical harmonic for central body gravitation. The algorithm includes a step size selection method that directly calculates the step size and never requires a repeat step. High-order Taylor series integration algorithms have been shown to provide major reductions in computer time over conventional integration methods in numerous scientific applications. The objective here was to directly implement Taylor series integration in an existing trajectory analysis code and demonstrate that large reductions in computer time (order of magnitude) could be achieved while simultaneously maintaining high accuracy. This software greatly accelerates the calculation of spacecraft trajectories. At each time level, the spacecraft position, velocity, and mass are expanded in a high-order Taylor series whose coefficients are obtained through efficient differentiation arithmetic. This makes it possible to take very large time steps at minimal cost, resulting in large savings in computer time. The Taylor series algorithm is implemented primarily through three subroutines: (1) a driver routine that automatically introduces auxiliary variables and

  11. Shapes of Venusian 'pancake' domes imply episodic emplacement and silicic composition

    Science.gov (United States)

    Fink, Jonathan H.; Bridges, Nathan T.; Grimm, Robert E.

    1993-01-01

    The main evidence available for constraining the composition of the large circular 'pancake' domes on Venus is their gross morphology. Laboratory simulations using polyethylene glycol show that the height to diameter (aspect) ratios of domes of a given total volume depend critically on whether their extrusion was continuous or episodic, with more episodes leading to greater cooling and taller domes. Thus without observations of their emplacement, the compositions of Venusian domes cannot be uniquely constrained by their morphology. However, by considering a population of 51 Venusian domes to represent a sampling of many stages during the growth of domes with comparable histories, and by plotting aspect ratio versus total volume, we find that the shapes of the domes are most consistent with episodic emplacement. On Earth this mode of dome growth is found almost exclusively in lavas of dacite to rhyolite composition, strengthening earlier inferences about the presence of evolved magmas on Venus.

  12. Assessment of tectonic hazards to waste storage in interior-basin salt domes

    International Nuclear Information System (INIS)

    Kehle, R.

    1979-01-01

    Salt domes in the northern Gulf of Mexico may make ideal sites for storage of radioactive waste because the area is tectonically quiet. The stability of such salt domes and the tectonic activity are discussed

  13. Oxygen isotope mass balance of atmospheric nitrate at Dome C, East Antarctica, during the OPALE campaign

    Directory of Open Access Journals (Sweden)

    J. Savarino

    2016-03-01

    Full Text Available Variations in the stable oxygen isotope composition of atmospheric nitrate act as novel tools for studying oxidative processes taking place in the troposphere. They provide both qualitative and quantitative constraints on the pathways determining the fate of atmospheric nitrogen oxides (NO + NO2 = NOx. The unique and distinctive 17O excess (Δ17O = δ17O − 0.52 × δ18O of ozone, which is transferred to NOx via oxidation, is a particularly useful isotopic fingerprint in studies of NOx transformations. Constraining the propagation of 17O excess within the NOx cycle is critical in polar areas, where there exists the possibility of extending atmospheric investigations to the glacial–interglacial timescale using deep ice core records of nitrate. Here we present measurements of the comprehensive isotopic composition of atmospheric nitrate collected at Dome C (East Antarctic Plateau during the austral summer of 2011/2012. Nitrate isotope analysis has been here combined for the first time with key precursors involved in nitrate production (NOx, O3, OH, HO2, RO2, etc. and direct observations of the transferrable Δ17O of surface ozone, which was measured at Dome C throughout 2012 using our recently developed analytical approach. Assuming that nitrate is mainly produced in Antarctica in summer through the OH + NO2 pathway and using concurrent measurements of OH and NO2, we calculated a Δ17O signature for nitrate on the order of (21–22 ± 3 ‰. These values are lower than the measured values that ranged between 27 and 31 ‰. This discrepancy between expected and observed Δ17O(NO3− values suggests the existence of an unknown process that contributes significantly to the atmospheric nitrate budget over this East Antarctic region. However, systematic errors or false isotopic balance transfer functions are not totally excluded.

  14. Ice Ages

    Indian Academy of Sciences (India)

    that the precession of the earth's orbit caused ice ages. The precession of the earth's orbit leads to changes in the time of the year at which ... than in the southern hemisphere. ..... small increase in ocean temperature implies a large increase in.

  15. Antarctic Ice Sheet Slope and Aspect Based on Icesat's Repeat Orbit Measurement

    Science.gov (United States)

    Yuan, L.; Li, F.; Zhang, S.; Xie, S.; Xiao, F.; Zhu, T.; Zhang, Y.

    2017-09-01

    Accurate information of ice sheet surface slope is essential for estimating elevation change by satellite altimetry measurement. A study is carried out to recover surface slope of Antarctic ice sheet from Ice, Cloud and land Elevation Satellite (ICESat) elevation measurements based on repeat orbits. ICESat provides repeat ground tracks within 200 meters in cross-track direction and 170 meters in along-track direction for most areas of Antarctic ice sheet. Both cross-track and along-track surface slopes could be obtained by adjacent repeat ground tracks. Combining those measurements yields a surface slope model with resolution of approximately 200 meters. An algorithm considering elevation change is developed to estimate the surface slope of Antarctic ice sheet. Three Antarctic Digital Elevation Models (DEMs) were used to calculate surface slopes. The surface slopes from DEMs are compared with estimates by using in situ GPS data in Dome A, the summit of Antarctic ice sheet. Our results reveal an average surface slope difference of 0.02 degree in Dome A. High resolution remote sensing images are also used in comparing the results derived from other DEMs and this paper. The comparison implies that our results have a slightly better coherence with GPS observation than results from DEMs, but our results provide more details and perform higher accuracy in coastal areas because of the higher resolution for ICESat measurements. Ice divides are estimated based on the aspect, and are weakly consistent with ice divides from other method in coastal regions.

  16. Development of the armoring technique for ITER Divertor Dome

    Energy Technology Data Exchange (ETDEWEB)

    Litunovsky, Nikolay, E-mail: nlitunovsky@sintez.niiefa.spb.su [D.V. Efremov Reseasch Institute, 3, Doroga na Metallostroy, Saint Petersburg (Russian Federation); Alekseenko, Evgeny; Makhankov, Alexey; Mazul, Igor [D.V. Efremov Reseasch Institute, 3, Doroga na Metallostroy, Saint Petersburg (Russian Federation)

    2011-10-15

    This paper describes the current status of the technique for armoring of Plasma Facing Units (PFUs) of the ITER Divertor Dome with flat tungsten tiles planned for application at the procurement stage. Application of high-temperature vacuum brazing for armoring of High Heat Flux (HHF) plasma facing components was traditionally developed at the Efremov Institute and successfully tried out at the ITER R and D stage by manufacturing and HHF testing of a number of W- and Be-armored mock-ups . Nevertheless, the so-called 'fast brazing' technique successfully applied in the past was abandoned at the stage of manufacturing of the Dome Qualification Prototypes (Dome QPs), as it failed to retain the mechanical properties of CuCrZr heat sink of the substrate. Another problem was a substantially increased number of armoring tiles brazed onto one substrate. Severe ITER requirements for the joints quality have forced us to refuse from production of W/Cu joints by brazing in favor of casting. These modifications have allowed us to produce ITER Divertor Dome QPs with high-quality tungsten armor, which then passed successfully the HHF testing. Further preparation to the procurement stage is in progress.

  17. An application of LOTEM around salt dome near Houston, Texas

    Science.gov (United States)

    Paembonan, Andri Yadi; Arjwech, Rungroj; Davydycheva, Sofia; Smirnov, Maxim; Strack, Kurt M.

    2017-07-01

    A salt dome is an important large geologic structure for hydrocarbon exploration. It may seal a porous reservoir of rocks that form petroleum reservoirs. Several techniques such as seismic, gravity, and electromagnetic including magnetotelluric have successfully yielded salt dome interpretation. Seismic has difficulties seeing through the salt because the seismic energy gets trapped by the salt due to its high velocity. Gravity and electromagnetics are more ideal methods. Long Offset Transient Electromagnetic (LOTEM) and Focused Source Electromagnetic (FSEM) were tested over a salt dome near Houston, Texas. LOTEM data were recorded at several stations with varying offset, and the FSEM tests were also made at some receiver locations near a suspected salt overhang. The data were processed using KMS's processing software: First, for assurance, including calibration and header checking; then transmitter and receiver data are merged and microseismic data is separated; Finally, data analysis and processing follows. LOTEM processing leads to inversion or in the FSEM case 3D modeling. Various 3D models verify the sensitivity under the salt dome. In addition, the processing was conducted pre-stack, stack, and post-stack. After pre-stacking, the noise was reduced, but showed the ringing effect due to a low-pass filter. Stacking and post-stacking with applying recursive average could reduce the Gibbs effect and produce smooth data.

  18. Morphometric and rheological study of lunar domes of Marius Hills ...

    Indian Academy of Sciences (India)

    70

    (2013) had given emphasis to the study of the morphology of cones having diameters between 1 to2 km using .... for the dome-35 is marked with a white polygon as shown in Fig.5a. Orthoimage, ..... Geochemical and mineralogical analysis of ...

  19. Determining the coordinates of lamps in an illumination dome

    Science.gov (United States)

    MacDonald, Lindsay W.; Ahmadabadian, Ali H.; Robson, Stuart

    2015-05-01

    The UCL Dome consists of an acrylic hemisphere of nominal diameter 1030 mm, fitted with 64 flash lights, arranged in three tiers of 16, one tier of 12, and one tier of 4 lights at approximately equal intervals. A Nikon D200 digital camera is mounted on a rigid steel frame at the `north pole' of the dome pointing vertically downwards with its optical axis normal to the horizontal baseboard in the `equatorial' plane. It is used to capture sets of images in pixel register for visualisation and surface reconstruction. Three techniques were employed for the geometric calibration of flash light positions in the dome: (1) the shadow cast by a vertical pin onto graph paper; (2) multi-image photogrammetry with retro-reflective targets; and (3) multi-image photogrammetry using the flash lights themselves as targets. The precision of the coordinates obtained by the three techniques was analysed, and it was found that although photogrammetric methods could locate individual targets to an accuracy of 20 μm, the uncertainty of locating the centroids of the flash lights was approximately 1.5 mm. This result was considered satisfactory for the purposes of using the dome for photometric imaging, and in particular for the visualisation of object surfaces by the polynomial texture mapping (PTM) technique.

  20. Dome-shaped macula: a compensatory mechanism in myopic anisometropia?

    Science.gov (United States)

    Keane, Pearse A; Mitra, Arijit; Khan, Imran J; Quhill, Fahd; Elsherbiny, Samer M

    2012-05-31

    The purpose of this article was to describe a patient with dome-shaped macula in the setting of mild myopic anisometropia and to speculate regarding the role of this feature as a compensatory mechanism in ocular development. The clinical records of a 49-year-old woman with this condition were reviewed. Spectral-domain optical coherence tomographic images revealed evidence of a dome-shaped macula. B-scan ultrasonography measured axial lengths of 23.8 mm in the right eye and 22.8 mm in the left eye. Spherical equivalents were -1.375 and +0.375 in the right and left eyes, respectively. Examination of the left eye was unremarkable. Dome-shaped macula has previously only been described in patients with high myopia. These findings support the hypothesis that myopic anisometropia, rather than absolute refractive status, is central to the development of dome-shaped macula and that this feature represents a protective mechanism aimed at reducing the effects of anisometropia. Copyright 2012, SLACK Incorporated.

  1. The Vredefort Dome World Heritage Site: Client satisfaction with ...

    African Journals Online (AJOL)

    Given the substantial growth of whitewater rafting in the Vredefort Dome World Heritage Site (VDWHS), it quickly grew into an unregulated adventure tourism commodity. With the area being a World Heritage Site, concerns have arisen about the impact it could have on the environment, service quality and public safety.

  2. Paradox Basin site characterization report: preparation papers, Gibson Dome location

    International Nuclear Information System (INIS)

    1982-11-01

    This document contains Part C, Identification of Pertinent Issues, of the site characterization report. The site characterization report, preparation papers, includes a description of detailed field studies and efforts to collect data to resolve key geologic and environmental issues in the Gibson Dome location within the Paradox Basin Region of Utah

  3. Instability behavior of stiffened dome liners under construction condition

    International Nuclear Information System (INIS)

    Jefts, A.R.; Guha-Majumdar, S.; Wanchoo, M.K.

    1977-01-01

    The purpose of this paper is to present techniques related to stability analysis, design concepts and behavior of dome liners. Various stiffening systems are examined from economy, schedule and constructablity point of view. The various failure modes can be classified as either buckling due to local instability or to an overall instability of the shell. Local instability may occur due to buckling of liner panel between a pair of rings and stringers or torsional and lateral buckling of the stiffeners. Methods are developed for proportioning stiffening system to preclude local buckling. Overall stability is a function of concrete pour height and thickness, loading distribution, time elapse between successive placements, rate of concrete placement, arrangement of stiffeners and other external supports. A computer program based on system energy minimization is used to study the overall instability of stiffened domes. Modelling techniques, effect of temperature and lack of bond, and their influence on results are discussed. Results for a self-standing stiffened hemispherical dome are presented in the form of mode shapes and buckling loads. Based on the results, a pouring scheme is recommended for an economical stiffening system. Recommendations are made to select the stiffening system and predict the buckling loads for preliminary analysis and design of the dome liner. Existing methods and code provisions related to tolerance, design criteria etc. are examined and recommendations made from practical considerations

  4. Ice age aerosol content from east Antarctic ice core samples and past wind strength

    International Nuclear Information System (INIS)

    Petit, J.R.; Briat, M.; Royer, A.

    1981-01-01

    The possible link between the aerosol content from the 905 deep Dome C ice core (East Antartica) which spans some 32,000 yr (Lorius et al. Nature; 280:644 (1979)) and climate, is considered. No evidence of major global or local volcanic activity was found though large marine and continental inputs (respectively 5 and 20 times higher than present) were observed at the end of the last Glacial stage. It is considered that they reflect glacial age climate with stronger atmospheric circulation, enhanced aridity and faster aerosol transport towards the Antarctic continent. (U.K.)

  5. Sustainable Outreach: Lessons Learned from Space Update and Discovery Dome

    Science.gov (United States)

    Reiff, P. H.; Sumners, C.; Law, C. C.

    2009-12-01

    A sustainable program lives on past its initial funding cycle, and develops a network of users that ensures continued life, either by fees, advertising revenue, or by making the program more successful in later sponsored grants. Teachers like free things, so having a sponsor for products such as lithographs or CD-Roms is key to wide distribution. In 1994 we developed “Space Update®”, under the NASA “Public Use of the Internet” program. It has new editions annually, with over 40,000 distributed so far (many purchased but most free at teacher and student workshops). In 1996 we created a special edition “Space Weather®”, which includes the space weather module from Space Update plus other resources. Initially developed with funding from the IMAGE mission, it is now sponsored by Cluster and MMS. A new edition is published annually and distributed in the “Sun-Earth Day” packet; total distribution now exceeds 180,000. “Earth Update” was created in 1999 under cooperative agreement “Museums Teaching Planet Earth”. It now has a total distribution of over 20,000. Both Earth Update and Space Update were developed to be museum kiosk software, and more than 15 museums have them on display. Over 4,000 users are active in our e-Teacher network and 577 in our museum educator network. Although these can certainly be considered successful because of their longevity and user base, we have had a far more dramatic sustainable program arise in the last six years… the “Discovery Dome®”. Invented at HMNS and developed under NASA Cooperative Agreement “Immersive Earth”, this dome was the first digital portable planetarium that also showed fulldome movies with an interactive interface (first shown to the public at the Dec 2003 AGU meeting). The Discovery Dome network (tinyurl.com/DiscDome) has spun those initial 6 NASA-funded domes into over 90 installations in 22 states and 23 countries. Creating high quality content is quite expensive and so needs

  6. Key variables influencing patterns of lava dome growth and collapse

    Science.gov (United States)

    Husain, T.; Elsworth, D.; Voight, B.; Mattioli, G. S.; Jansma, P. E.

    2013-12-01

    Lava domes are conical structures that grow by the infusion of viscous silicic or intermediate composition magma from a central volcanic conduit. Dome growth can be characterized by repeated cycles of growth punctuated by collapse, as the structure becomes oversized for its composite strength. Within these cycles, deformation ranges from slow long term deformation to sudden deep-seated collapses. Collapses may range from small raveling failures to voluminous and fast-moving pyroclastic flows with rapid and long-downslope-reach from the edifice. Infusion rate and magma rheology together with crystallization temperature and volatile content govern the spatial distribution of strength in the structure. Solidification, driven by degassing-induced crystallization of magma leads to the formation of a continuously evolving frictional talus as a hard outer shell. This shell encapsulates the cohesion-dominated soft ductile core. Here we explore the mechanics of lava dome growth and failure using a two-dimensional particle-dynamics model. This meshless model follows the natural evolution of a brittle carapace formed by loss of volatiles and rheological stiffening and avoids difficulties of hour-glassing and mesh-entangelment typical in meshed models. We test the fidelity of the model against existing experimental and observational models of lava dome growth. The particle-dynamics model follows the natural development of dome growth and collapse which is infeasible using simple analytical models. The model provides insight into the triggers that lead to the transition in collapse mechasnism from shallow flank collapse to deep seated sector collapse. Increase in material stiffness due to decrease in infusion rate results in the transition of growth pattern from endogenous to exogenous. The material stiffness and strength are strongly controlled by the magma infusion rate. Increase in infusion rate decreases the time available for degassing induced crystallization leading to a

  7. Peeking Below the Snow Surface to Explore Amundsen Sea Climate Variability and Locate Optimal Ice-Core Sites

    Science.gov (United States)

    Neff, P. D.; Fudge, T. J.; Medley, B.

    2016-12-01

    Observations over recent decades reveal rapid changes in ice shelves and fast-flowing grounded ice along the Amundsen Sea coast of the West Antarctic Ice Sheet (WAIS). Long-term perspectives on this ongoing ice loss are needed to address a central question of Antarctic research: how much and how fast will Antarctic ice-loss raise sea level? Ice cores can provide insight into past variability of the atmospheric (wind) forcing of regional ocean dynamics affecting ice loss. Interannual variability of snow accumulation on coastal ice domes grounded near or within ice shelves reflects local to regional atmospheric circulation near the ice-ocean interface. Records of snow accumulation inferred from shallow ice cores strongly correlate with reanalysis precipitation and pressure fields, but ice cores have not yet been retrieved along the Amundsen Sea coast. High-frequency airborne radar data (NASA Operation IceBridge), however, have been collected over this region and we demonstrate that these data accurately reflect annual stratigraphy in shallow snow and firn (1 to 2 decades of accumulation). This further validates the agreement between radar snow accumulation records and climate reanalysis products. We then explore regional climate controls on local snow accumulation through comparison with gridded reanalysis products, providing a preview of what information longer coastal ice core records may provide with respect to past atmospheric forcing of ocean circulation and WAIS ice loss.

  8. Horizontally viscous effects in a tidal basin: extending Taylor's problem

    NARCIS (Netherlands)

    Roos, Pieter C.; Schuttelaars, H.M.

    2009-01-01

    The classical problem of Taylor (Proc. Lond. Math. Soc., vol. 20, 1921, pp. 148–181) of Kelvin wave reflection in a semi-enclosed rectangular basin of uniform depth is extended to account for horizontally viscous effects. To this end, we add horizontally viscous terms to the hydrodynamic model

  9. Traveling waves in a magnetized Taylor-Couette flow

    International Nuclear Information System (INIS)

    Liu Wei; Ji Hantao; Goodman, Jeremy

    2007-01-01

    We investigate numerically a traveling wave pattern observed in experimental magnetized Taylor-Couette flow at low magnetic Reynolds number. By accurately modeling viscous and magnetic boundaries in all directions, we reproduce the experimentally measured wave patterns and their amplitudes. Contrary to previous claims, the waves are shown to be transiently amplified disturbances launched by viscous boundary layers, rather than globally unstable magnetorotational modes

  10. Investigation of the Taylor vortices in electrovortex flow

    Science.gov (United States)

    Vinogradov, D. A.; Ivochkin, Yu P.; Teplyakov, I. O.

    2017-10-01

    The structure of the electrovortex flow appearing when the electric current passing through the liquid metal interacts with own and external magnetic fields was investigated numerically. It was shown that axial external magnetic field leads to the rotation of the liquid and generates secondary flow similar to Taylor vortex. Calculations were carried out for various ratios of electrode sizes.

  11. Autenticitet og kritisk sprogfællesskab hos Charles Taylor

    DEFF Research Database (Denmark)

    Crone, Manni

    2002-01-01

    Lever vi i individualistiske samfund, hvor autenticitet og selvrealisering er blevet de højeste værdier? Den canadiske kommunitarist Charles Taylor argumenterer for, at selv om autenticitet og selvrealisering er vigtige værdier for det moderne menneske, kan en excessiv individualisme alligevel...

  12. Taylor dispersion of colloidal particles in narrow channels

    NARCIS (Netherlands)

    Sane, J.; Padding, J.T.; Louis, A.A.

    2015-01-01

    Special issue in Honor of Jean-Pierre Hansen We use a mesoscopic particle-based simulation technique to study the classic convection-diffusion problem of Taylor dispersion for colloidal discs in confined flow. When the disc diameter becomes non-negligible compared to the diameter of the pipe, there

  13. Taylorism, Tylerism, and Performance Indicators: Defending the Indefensible?

    Science.gov (United States)

    Helsby, Gill; Saunders, Murray

    1993-01-01

    Explores the antecedents to the growing interest in the use of educational performance indicators. Discusses this issue in relation to the work of economist F. W. Taylor and evaluator Ralph Tyler. Describes a five-year project that demonstrates the promise of teacher-developed performance indicators. (CFR)

  14. Evidence for mate guarding behavior in the Taylor's checkerspot butterfly

    Science.gov (United States)

    Victoria J. Bennett; Winston P. Smith; Matthew G. Betts

    2011-01-01

    Discerning the intricacies of mating systems in butterflies can be difficult, particularly when multiple mating strategies are employed and are cryptic and not exclusive. We observed the behavior and habitat use of 113 male Taylor's checkerspot butterflies (Euphydryas editha taylori). We confirmed that two distinct mating strategies were...

  15. Rayleigh-Taylor convective overturn in stellar collapse

    International Nuclear Information System (INIS)

    Bruenn, S.W.; Buchler, J.R.; Livio, M.

    1979-01-01

    Rayleigh--Taylor convective overturn in collapsing stellar cores is modeled with a one-dimensional parametrization. The results of a numerical hydrodynamic study are very encouraging and indicate that such an overturn could well be a dominant feature in the supernova explosion mechanism

  16. The Rayleigh–Taylor Instability Among the Stars

    Indian Academy of Sciences (India)

    The Rayleigh–Taylor Instability Among the Stars. Rajaram Nityananda. Rajaram Nityananda works at the School of Liberal. Studies, Azim Premji. University, Bengaluru. Earlier, he spent a decade at the National Centre for Radio. Astrophysics in Pune, and more than two decades at the. Raman Research Institute in.

  17. Using Taylor Expansions to Prepare Students for Calculus

    Science.gov (United States)

    Lutzer, Carl V.

    2011-01-01

    We propose an alternative to the standard introduction to the derivative. Instead of using limits of difference quotients, students develop Taylor expansions of polynomials. This alternative allows students to develop many of the central ideas about the derivative at an intuitive level, using only skills and concepts from precalculus, and…

  18. Liz Taylor : minu van Gogh pole natsidele kuulunud

    Index Scriptorium Estoniae

    2004-01-01

    Elizabeth Taylor palus kohtult otsust, et talle kuuluvat 15 miljonit dollarit maksvat Vincent van Goghi maali "Vaade Saint-Remy varjupaigale" pole natsid Margarete Mauthneri juudiperekonna käest vägivaldselt ära võtnud. E. Taylori isa ostis maali 1963. a. Londonis oksjonilt

  19. Monetary Policy and the Taylor Principle in Open Economies

    NARCIS (Netherlands)

    Linnemann, L.; Schabert, A.

    2006-01-01

    Nowadays, central banks mostly conduct monetary policy by setting nominal interest rates. A widely held view is that central banks can stabilize inflation if they follow the Taylor principle, which requires raising the nominal interest rate more than one-for-one in response to higher inflation. Is

  20. Eulerian Method for Ice Crystal Icing

    NARCIS (Netherlands)

    Norde, Ellen; van der Weide, Edwin Theodorus Antonius; Hoeijmakers, Hendrik Willem Marie

    In this study, an ice accretion method aimed at ice crystal icing in turbofan engines is developed and demonstrated for glaciated as well as mixed-phase icing conditions. The particle trajectories are computed by an Eulerian trajectory method. The effects of heat transfer and phase change on the

  1. Sea ice - Multiyear cycles and white ice

    Science.gov (United States)

    Ledley, T. S.

    1985-01-01

    The multiyear thickness cycles represent one of the interesting features of the sea ice studies performed by Semtner (1976) and Washington et al. (1976) with simple thermodynamic models of sea ice. In the present article, a description is given of results which show that the insulating effect of snow on the surface of the sea ice is important in producing these multiyear cycles given the physics included in the model. However, when the formation of white ice is included, the cycles almost disappear. White ice is the ice which forms at the snow-ice interface when the snow layer becomes thick enough to depress the ice below the water level. Water infiltrates the snow by coming through the ice at leads and generally freezes there, forming white ice.

  2. Application of Taylor-Series Integration to Reentry Problems with Wind

    NARCIS (Netherlands)

    Bergsma, Michiel; Mooij, E.

    2016-01-01

    Taylor-series integration is a numerical integration technique that computes the Taylor series of state variables using recurrence relations and uses this series to propagate the state in time. A Taylor-series integration reentry integrator is developed and compared with the fifth-order

  3. Electrical structure beneath the Hangai Dome, Mongolia, from magnetotelluric data

    Science.gov (United States)

    Comeau, Matthew; Käufl, Johannes; Becken, Michael; Kuvshinov, Alexey; Demberel, Sodnomsambuu; Sukhbaatar, Usnikh; Batmagnai, Erdenechimeg; Tserendug, Shoovdor; Nasan, Ochir

    2017-04-01

    The Hangai Dome in west-central Mongolia is an unusual high-elevation intra-continental plateau located far from tectonic plate boundaries and characterized by dispersed, low-volume, basaltic volcanism. This region is an ideal natural laboratory for studying intra-continental orogenic and magmatic processes resulting from crust-mantle interactions. The processes responsible for developing the Hangai Dome remain unexplained, due in part to a lack of high resolution geophysical data over the area. Here we present newly acquired broadband (0.008 - 3,000 s) magnetotelluric (MT) data from a large-scale ( 200 x 450 km) and high resolution (site spacing > 5 km) survey across the Hangai Dome. A total of 125 sites were collected and include full MT sites and telluric-only sites where inter-station transfer functions were computed. The MT data are used to generate an electrical resistivity model of the crust and upper mantle below the Hangai Dome. The model shows that the lower crust ( 30 - 50 km; below the brittle-ductile transition zone) beneath the Hangai Dome contains anomalous discrete pockets of low-resistivity ( 30 ohm-m) material that indicate the presence of local accumulations of fluids and/or low-percent partial melts. These anomalous regions appear to be spatially associated with the surface expressions of past volcanism, hydrothermal activity, and an increase in heat flow. They also correlate with observed crustal low-density and low-velocity anomalies. However they are in contrast to some geochemical and petrological studies which show long-lived crustal melt storage is impossible below the Hangai due to limited crustal assimilation and crustal contamination, arguing for a single parent-source at mantle depths. The upper mantle ( 6%) at this location. The results are consistent with modern geochemical and geophysical data, which show a thin lithosphere below the Hangai region. Furthermore the results agree with geodynamic models that require a low-heat flux

  4. Geological evaluation of Gulf Coast salt domes: overall assessment of the Gulf Interior Region

    International Nuclear Information System (INIS)

    1981-10-01

    The three major phases in site characterization and selection are regional studies, area studies, and location studies. This report characterizes regional geologic aspects of the Gulf Coast salt dome basins. It includes general information from published sources on the regional geology; the tectonic, domal, and hydrologic stability; and a brief description the salt domes to be investigated. After a screening exercise, eight domes were chosen for further characterization: Keechi, Oakwood, and Palestine Domes in Texas; Vacherie and Rayburn's domes in North Louisiana; and Cypress Creek and Richton domes in Mississippi. A general description of each, maps of the location, property ownership, and surface geology, and a geologic cross section were presented for each dome

  5. Geological evaluation of Gulf Coast salt domes: overall assessment of the Gulf Interior Region

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-10-01

    The three major phases in site characterization and selection are regional studies, area studies, and location studies. This report characterizes regional geologic aspects of the Gulf Coast salt dome basins. It includes general information from published sources on the regional geology; the tectonic, domal, and hydrologic stability; and a brief description the salt domes to be investigated. After a screening exercise, eight domes were chosen for further characterization: Keechi, Oakwood, and Palestine Domes in Texas; Vacherie and Rayburn's domes in North Louisiana; and Cypress Creek and Richton domes in Mississippi. A general description of each, maps of the location, property ownership, and surface geology, and a geologic cross section were presented for each dome.

  6. Forecasting Turbine Icing Events

    DEFF Research Database (Denmark)

    Davis, Neil; Hahmann, Andrea N.; Clausen, Niels-Erik

    2012-01-01

    In this study, we present a method for forecasting icing events. The method is validated at two European wind farms in with known icing events. The icing model used was developed using current ice accretion methods, and newly developed ablation algorithms. The model is driven by inputs from the WRF...... mesoscale model, allowing for both climatological estimates of icing and short term icing forecasts. The current model was able to detect periods of icing reasonably well at the warmer site. However at the cold climate site, the model was not able to remove ice quickly enough leading to large ice...

  7. Volcanic synchronisation of the EPICA-DC and TALDICE ice cores for the last 42 kyr BP

    Science.gov (United States)

    Severi, M.; Udisti, R.; Becagli, S.; Stenni, B.; Traversi, R.

    2012-04-01

    An age scale synchronisation between the Talos Dome and the EPICA Dome C ice cores was carried on through the identification of several common volcanic signatures for the last 42 kyr. Using this tight stratigraphic link we transferred the EDC age scale to the Talos Dome ice core producing a new age scale for the last 12 kyr. We estimated the discrepancies between the modeled TALDICE-1 age scale and the new one during the studied period, by evaluating the ratio R of the apparent duration of temporal intervals between pairs of isochrones. Except for a very few cases, R ranges between 0.8 and 1.2 corresponding to an uncertainty of up to 20% in the estimate of the time duration in at least one of the two ice cores. At this stage our approach does not allow us unequivocally to find out which of the models is affected by errors, but, taking into account only the historically known volcanic events, we found that discrepancies up to 200 years appears in the last two millennia in the TALDICE-1 model, while our new age scale shows a much better agreement with the volcanic absolute horizons. Thus, we propose for the Talos Dome ice core a new age scale (covering the whole Holocene) obtained by a direct transfer, via our stratigraphic link, from the EDC modelled age scale by Lemieux-Dudon et al. (2010).

  8. New phenomena in variable-density Rayleigh-Taylor turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Livescu, D; Ristorcelli, J R; Petersen, M R; Gore, R A, E-mail: livescu@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2010-12-15

    This paper presents several issues related to mixing and turbulence structure in buoyancy-driven turbulence at low to moderate Atwood numbers, A, found from direct numerical simulations in two configurations: classical Rayleigh-Taylor instability and an idealized triply periodic Rayleigh-Taylor flow. Simulations at A up to 0.5 are used to examine the turbulence characteristics and contrast them with those obtained close to the Boussinesq approximation. The data sets used represent the largest simulations to date in each configuration. One of the more remarkable issues explored, first reported in (Livescu and Ristorcelli 2008 J. Fluid Mech. 605 145-80), is the marked difference in mixing between different density fluids as opposed to the mixing that occurs between fluids of commensurate densities, corresponding to the Boussinesq approximation. Thus, in the triply periodic configuration and the non-Boussinesq case, an initially symmetric density probability density function becomes skewed, showing that the mixing is asymmetric, with pure heavy fluid mixing more slowly than pure light fluid. A mechanism producing the mixing asymmetry is proposed and the consequences for the classical Rayleigh-Taylor configuration are discussed. In addition, it is shown that anomalous small-scale anisotropy found in the homogeneous configuration (Livescu and Ristorcelli 2008 J. Fluid Mech. 605 145-80) and Rayleigh-Taylor turbulence at A=0.5 (Livescu et al 2008 J. Turbul. 10 1-32) also occurs near the Boussinesq limit. Results pertaining to the moment closure modelling of Rayleigh-Taylor turbulence are also presented. Although the Rayleigh-Taylor mixing layer width reaches self-similar growth relatively fast, the lower-order terms in the self-similar expressions for turbulence moments have long-lasting effects and derived quantities, such as the turbulent Reynolds number, are slow to follow the self-similar predictions. Since eddy diffusivity in the popular gradient transport hypothesis

  9. Advanced imaging techniques III: a scalable and modular dome illumination system for scientific microphotography on a budget

    Science.gov (United States)

    A scalable and modular LED illumination dome for microscopic scientific photography is described and illustrated, and methods for constructing such a dome are detailed. Dome illumination for insect specimens has become standard practice across the field of insect systematics, but many dome designs ...

  10. Visualisation and Immersion Dome Experience for Inspired Participation

    Directory of Open Access Journals (Sweden)

    Anna P. Gawlikowska

    2018-03-01

    Full Text Available Public protests, which lead to increased administrative and permission procedures, are amongst the most important obstacles in development of wind energy projects. The community’s fears of visual and acoustic impacts of new power plants are commonly recognized as the weakest aspects of public acceptance. To address these issues Visualisation Dome has been designed to better communicate the economic, political, spatial, ecological and social benefits of wind power plants and the associated risks to local communities. The approach combines the experimental and simulation method. The integrated analysis software tool, which allows assessing the impacts of planed wind power plants underpins their 360-degree video and audio simulations. The Visualisation Dome demonstration resulted in 57% of the interviewed participants improving their opinion of wind power following the experience. Visualisation Dome’s novel approach for improving procedural justice of wind energy projects development forms innovative, interactive and streamlined processes, and enables constructive participation of audiences.

  11. Dome-shaped macula associated with Best vitelliform macular dystrophy.

    Science.gov (United States)

    Battaglia Parodi, Maurizio; Zucchiatti, Ilaria; Fasce, Francesco; Cascavilla, Maria Lucia; Cicinelli, Maria Vittoria; Bandello, Francesco

    2015-01-01

    Dome-shaped macula (DSM) has been described recently as an inward convexity of the macula typical of myopic eyes detectable on spectral-domain optical coherence tomography (SD-OCT). The authors describe a case of monolateral DSM associated with Best vitelliform macular dystrophy (VMD). Case report. A 60-year-old man already diagnosed with VMD in vitelliruptive stage underwent SD-OCT that revealed the typical vitelliform material accumulation associated in the left eye with a convex elevation of the macula. No change was registered over a 1-year follow-up. This is the first report describing a monolateral DSM associated with VMD. Dome-shaped macula could be considered as a nonspecific scleral alteration, probably due to increased scleral thickness, which can accompany many retinal disorders.

  12. Assessments of Ali, Dome A, and Summit Camp for mm-wave Observations Using MERRA-2 Reanalysis

    Science.gov (United States)

    Kuo, Chao-Lin

    2017-10-01

    NASA’s latest MERRA-2 reanalysis of the modern satellite measurements has made atmospheric data easily accessible with unprecedented uniformity, fidelity, and completeness. In this paper, these data are used to evaluate five sites for millimeter-wave (mm-wave) observations. These include two established sites (South Pole and Chajnantor, Atacama), and three new sites (Ali in Tibet, Dome A in Antarctica, and Summit Camp in Greenland). Atmospheric properties including precipitable water vapor (PWV), sky brightness temperature fluctuations, and ice and liquid water paths are derived and compared. Dome A emerges to be the best among those evaluated, with PWV and fluctuations smaller than the second-best site, South Pole, by more than a factor of 2. It is found that the higher site in Ali (6100 m) is on par with Cerro Chajnantor (5612 m) in terms of transmission and stability. The lower site in Ali (5250 m) planned for the first stage of observations at 90/150 GHz provides conditions comparable to those on the Chajnantor Plateau. These analyses confirm Ali to be an excellent mm-wave site in the Northern Hemisphere that will complement well-established Southern sites. According to MERRA-2 data, the observing conditions at Summit Camp are also comparable to Cerro Chajnantor. However, it is more affected by the presence of liquid water clouds.

  13. Assessments of Ali, Dome A, and Summit Camp for mm-wave Observations Using MERRA-2 Reanalysis

    International Nuclear Information System (INIS)

    Kuo, Chao-Lin

    2017-01-01

    NASA's latest MERRA-2 reanalysis of the modern satellite measurements has made atmospheric data easily accessible with unprecedented uniformity, fidelity, and completeness. In this paper, these data are used to evaluate five sites for millimeter-wave (mm-wave) observations. These include two established sites (South Pole and Chajnantor, Atacama), and three new sites (Ali in Tibet, Dome A in Antarctica, and Summit Camp in Greenland). Atmospheric properties including precipitable water vapor (PWV), sky brightness temperature fluctuations, and ice and liquid water paths are derived and compared. Dome A emerges to be the best among those evaluated, with PWV and fluctuations smaller than the second-best site, South Pole, by more than a factor of 2. It is found that the higher site in Ali (6100 m) is on par with Cerro Chajnantor (5612 m) in terms of transmission and stability. The lower site in Ali (5250 m) planned for the first stage of observations at 90/150 GHz provides conditions comparable to those on the Chajnantor Plateau. These analyses confirm Ali to be an excellent mm-wave site in the Northern Hemisphere that will complement well-established Southern sites. According to MERRA-2 data, the observing conditions at Summit Camp are also comparable to Cerro Chajnantor. Furthermore, it is more affected by the presence of liquid water clouds.

  14. The Philosophical Genealogy of Taylor's Social Imaginaries: A Complex History of Ideas and Predecessors.

    Science.gov (United States)

    Vanheeswijck, Guido M

    2017-01-01

    The deepest sources of Charles Taylor's use of the concept "social imaginaries" are often related to political philosophy or social anthropology (Anderson, Castoriadis). The purpose of this article is to show that they also form part of Taylor's struggle to overcome the epistemological construal in modern philosophy and culture. Taylor locates the concept "social imaginaries" in the Kantian tradition, identifying their role to that of transcendental schemes. However, there remains a central difference between Kant's transcendental schemes and Taylor's social imaginaries. To elucidate that difference, this article will track the philosophical genealogy of Taylor's concept of "social imaginaries" in three steps.

  15. Kaguyak dome field and its Holocene caldera, Alaska Peninsula

    Science.gov (United States)

    Fierstein, J.; Hildreth, W.

    2008-01-01

    Kaguyak Caldera lies in a remote corner of Katmai National Park, 375??km SW of Anchorage, Alaska. The 2.5-by-3-km caldera collapsed ~ 5.8 ?? 0.2??ka (14C age) during emplacement of a radial apron of poorly pumiceous crystal-rich dacitic pyroclastic flows (61-67% SiO2). Proximal pumice-fall deposits are thin and sparsely preserved, but an oxidized coignimbrite ash is found as far as the Valley of Ten Thousand Smokes, 80??km southwest. Postcaldera events include filling the 150-m-deep caldera lake, emplacement of two intracaldera domes (61.5-64.5% SiO2), and phreatic ejection of lakefloor sediments onto the caldera rim. CO2 and H2S bubble up through the lake, weakly but widely. Geochemical analyses (n = 148), including pre-and post-caldera lavas (53-74% SiO2), define one of the lowest-K arc suites in Alaska. The precaldera edifice was not a stratocone but was, instead, nine contiguous but discrete clusters of lava domes, themselves stacks of rhyolite to basalt exogenous lobes and flows. Four extracaldera clusters are mid-to-late Pleistocene, but the other five are younger than 60??ka, were truncated by the collapse, and now make up the steep inner walls. The climactic ignimbrite was preceded by ~ 200??years by radial emplacement of a 100-m-thick sheet of block-rich glassy lava breccia (62-65.5% SiO2). Filling the notches between the truncated dome clusters, the breccia now makes up three segments of the steep caldera wall, which beheads gullies incised into the breccia deposit prior to caldera formation. They were probably shed by a large lava dome extruding where the lake is today.

  16. Dual Innervation of Neonatal Merkel Cells in Mouse Touch Domes

    Science.gov (United States)

    Luo, Wenqin

    2014-01-01

    Merkel cell-neurite complexes are specialized mechanosensory end organs that mediate discriminative touch sensation. It is well established that type I slowly adapting (SAI) mechanoreceptors, which express neural filament heavy chain (NFH), innervate Merkel cells. It was previously shown that neurotrophic factor NT3 and its receptor TrkC play crucial roles in controlling touch dome Merkel cell innervation of NFH+ fibers. In addition, nerve fibers expressing another neurotrophic tyrosine receptor kinase (NTRK), Ret, innervate touch dome Merkel cells as well. However, the relationship between afferents responsive to NT3/TrkC signaling and those expressing Ret is unclear. It is also controversial if these Ret+ fibers belong to the early or late Ret+ DRG neurons, which are defined based on the co-expression and developmental dependence of TrkA. To address these questions, we genetically traced Ret+ and TrkC+ fibers and analyzed their developmental dependence on TrkA. We found that Merkel cells in neonatal mouse touch domes receive innervation of two types of fibers: one group is Ret+, while the other subset expresses TrkC and NFH. In addition, Ret+ fibers depend on TrkA for their survival and normal innervation whereas NFH+ Merkel cell innervating fibers are almost unaltered in TrkA mutant mice, supporting that Ret+ and NFH+/TrkC+ afferents are two distinct groups. Ret signaling, on the other hand, plays a minor role for the innervation of neonatal touch domes. In contrast, Merkel cells in the glabrous skin are mainly contacted by NFH+/TrkC+ afferents. Taken together, our results suggest that neonatal Merkel cells around hair follicles receive dual innervation while Merkel cells in the glabrous skin are mainly innervated by only SAI mechanoreceptors. In addition, our results suggest that neonatal Ret+ Merkel cell innervating fibers most likely belong to the late but not early Ret+ DRG neurons. PMID:24637732

  17. The effect of Rayleigh-Taylor instabilities on the thickness of undifferentiated crust on Kuiper Belt Objects

    Science.gov (United States)

    Rubin, Mark E.; Desch, Steven J.; Neveu, Marc

    2014-07-01

    Previous calculations of the internal structure and thermal evolution of Kuiper Belt Objects (KBOs) by Desch et al. (Desch, S.J., Cook, J.C., Doggett, T.C., Porter, S.B. [2009]. Icarus 202, 694-714) have predicted that KBOs should only partially differentiate, with rock and ice separating into a rocky core and icy mantle, below an undifferentiated crust of ice and rock. This crust is thermally insulating and enhances the ability of subsurface liquid to persist within KBOs. A dense rock/ice layer resting on an icy mantle is gravitationally unstable and prone to Rayleigh-Taylor (RT) instabilities, and may potentially overturn. Here we calculate the ability of RT instabilities to act in KBOs, and determine the thickness of undifferentiated crusts. We have used previously calculated growth rates of the RT instability to determine the critical viscosity of ice needed for the RT instability to operate. We calculate the viscosity of ice at the cold temperatures and long timescales relevant to KBOs. We find that crustal overturn is only possible where the temperature exceeds about 150 K, and that RT instabilities cannot act on geological timescales within about 60 km of the surfaces of a KBO like Charon. Although this crustal thickness is less than the 85 km previously calculated by Desch et al. (Desch, S.J., Cook, J.C., Doggett, T.C., Porter, S.B. [2009]. Icarus 202, 694-714), it is still significant, representing ≈25% of the mass of the KBO. We conclude that while RT instabilities may act in KBOs, they do not completely overturn their crusts. We calculate that Saturn’s moon Rhea should only partially differentiate, resulting in a moment of inertia C/MR2≈0.38.

  18. Axisymmetric modeling of prestressing tendons in nuclear containment dome

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Se-Jin [DAEWOO E and C, Institute of Construction Technology, 60 Songjook-dong, Jangan-gu, Suwon, Kyonggi 440-210 (Korea, Republic of)]. E-mail: jsj@dwconst.co.kr; Chung, Chul-Hun [Department of Civil and Environmental Engineering, Dankook University, San 8, Hannam-dong, Youngsan-gu, Seoul 140-714 (Korea, Republic of)

    2005-12-15

    Simple axisymmetric modeling of a nuclear containment building has been often employed in practice to estimate structural behavior for the axisymmetric loadings such as internal pressure. In this case, the prestressing tendons placed in the containment dome should be axisymmetrically approximated, since most dome tendons are not arranged in an axisymmetric manner. Some procedures are proposed that can realistically implement the actual three-dimensional tendon stiffness and prestressing effect into the axisymmetric model. Prestressing tendons, which are arranged in two or three ways depending on a containment type, are converted into the equivalent layer to consider the stiffness contribution in meridional and hoop directions. In order to reflect the prestressing effect, the equivalent load method and the initial stress method are devised, respectively, and the corresponding loads or stresses are derived in terms of the axisymmetric model. The proposed schemes are verified through some numerical examples comparing the results of the axisymmetric models to those of the actual three-dimensional model. The examples show that the proper level of the prestressing in the hoop direction of the axisymmetric dome plays an important role in tracing the actual behavior induced by the prestressing. Finally, some correction factors are discussed that can further improve the analysis results.

  19. Axisymmetric modeling of prestressing tendons in nuclear containment dome

    International Nuclear Information System (INIS)

    Jeon, Se-Jin; Chung, Chul-Hun

    2005-01-01

    Simple axisymmetric modeling of a nuclear containment building has been often employed in practice to estimate structural behavior for the axisymmetric loadings such as internal pressure. In this case, the prestressing tendons placed in the containment dome should be axisymmetrically approximated, since most dome tendons are not arranged in an axisymmetric manner. Some procedures are proposed that can realistically implement the actual three-dimensional tendon stiffness and prestressing effect into the axisymmetric model. Prestressing tendons, which are arranged in two or three ways depending on a containment type, are converted into the equivalent layer to consider the stiffness contribution in meridional and hoop directions. In order to reflect the prestressing effect, the equivalent load method and the initial stress method are devised, respectively, and the corresponding loads or stresses are derived in terms of the axisymmetric model. The proposed schemes are verified through some numerical examples comparing the results of the axisymmetric models to those of the actual three-dimensional model. The examples show that the proper level of the prestressing in the hoop direction of the axisymmetric dome plays an important role in tracing the actual behavior induced by the prestressing. Finally, some correction factors are discussed that can further improve the analysis results

  20. Characterization of the two-phase Taylor Couette flow

    International Nuclear Information System (INIS)

    Mehel A; Gabillet B; Djeridi H

    2005-01-01

    The focus of the present study concerns the effects of a dispersed phase on the structure of a quasi periodic Couette Taylor flow. The two phase flow patterns are investigated experimentally for the Taylor number Ta=780. Small bubbles (0.035 times as small as the gap) are generated by agitation of the upper free surface. Larger bubbles (0.15 times as small as the gap) are produced by injection at the bottom of the apparatus associated with a pressure drop. Void fraction, bubble size and velocity are measured, as well as the azimuthal and axial velocity components of the liquid. A premature transition to turbulence is pointed out and discussed according to the bubble size and their localization in the gap. (authors)

  1. Clinical utility of the Taylor spatial frame for limb deformities

    Directory of Open Access Journals (Sweden)

    Keshet D

    2017-05-01

    Full Text Available Doron Keshet, Mark Eidelman Pediatric Orthopedics Unit, Rambam Health Care Center, Haifa, Israel Abstract: The Taylor spatial frame (TSF is a hexapod external fixator that can correct six-axis deformities. The mathematical base of all hexapod systems is projective geometry, which describes complex repositioning of an object in space. The Taylor brothers developed one of the first six-axis correction systems, which is known today as TSF. Over the years, this system has become the most used six-axis deformity correction device. In this review, we describe the history behind TSF development, and describe the principles and clinical utility for application of the TSF in different settings, such as acute trauma, malunions, and various deformities of the lower and upper limb. Keywords: external fixator, deformity correction, hexapod

  2. Rayleigh-Taylor/gravitational instability in dense magnetoplasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S., E-mail: shahid.ali@ncp.edu.p [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad (Pakistan); IPFN, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ahmed, Z. [COMSATS Institute of Information Technology, Department of Physics, Wah Campus (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ahmad, I. [COMSATS Institute of Information Technology, Department of Physics, Islamabad Campus (Pakistan)

    2009-08-10

    The Rayleigh-Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh-Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

  3. Advection and Taylor-Aris dispersion in rivulet flow

    Science.gov (United States)

    Al Mukahal, F. H. H.; Duffy, B. R.; Wilson, S. K.

    2017-11-01

    Motivated by the need for a better understanding of the transport of solutes in microfluidic flows with free surfaces, the advection and dispersion of a passive solute in steady unidirectional flow of a thin uniform rivulet on an inclined planar substrate driven by gravity and/or a uniform longitudinal surface shear stress are analysed. Firstly, we describe the short-time advection of both an initially semi-infinite and an initially finite slug of solute of uniform concentration. Secondly, we describe the long-time Taylor-Aris dispersion of an initially finite slug of solute. In particular, we obtain the general expression for the effective diffusivity for Taylor-Aris dispersion in such a rivulet, and discuss in detail its different interpretations in the special case of a rivulet on a vertical substrate.

  4. Applicability of Taylor's hypothesis in thermally driven turbulence

    Science.gov (United States)

    Kumar, Abhishek; Verma, Mahendra K.

    2018-04-01

    In this paper, we show that, in the presence of large-scale circulation (LSC), Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal convection using real-space probes, a popular experimental tool. We perform numerical simulation of turbulent convection in a cube and observe that the velocity field follows Kolmogorov's spectrum (k-5/3). We also record the velocity time series using real-space probes near the lateral walls. The corresponding frequency spectrum exhibits Kolmogorov's spectrum (f-5/3), thus validating Taylor's hypothesis with the steady LSC playing the role of a mean velocity field. The aforementioned findings based on real-space probes provide valuable inputs for experimental measurements used for studying the spectrum of convective turbulence.

  5. Rayleigh-Taylor/gravitational instability in dense magnetoplasmas

    International Nuclear Information System (INIS)

    Ali, S.; Ahmed, Z.; Mirza, Arshad M.; Ahmad, I.

    2009-01-01

    The Rayleigh-Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh-Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

  6. A Taylor weak-statement algorithm for hyperbolic conservation laws

    Science.gov (United States)

    Baker, A. J.; Kim, J. W.

    1987-01-01

    Finite element analysis, applied to computational fluid dynamics (CFD) problem classes, presents a formal procedure for establishing the ingredients of a discrete approximation numerical solution algorithm. A classical Galerkin weak-statement formulation, formed on a Taylor series extension of the conservation law system, is developed herein that embeds a set of parameters eligible for constraint according to specification of suitable norms. The derived family of Taylor weak statements is shown to contain, as special cases, over one dozen independently derived CFD algorithms published over the past several decades for the high speed flow problem class. A theoretical analysis is completed that facilitates direct qualitative comparisons. Numerical results for definitive linear and nonlinear test problems permit direct quantitative performance comparisons.

  7. Pediatric and adolescent applications of the Taylor Spatial Frame.

    Science.gov (United States)

    Paloski, Michael; Taylor, Benjamin C; Iobst, Christopher; Pugh, Kevin J

    2012-06-01

    Limb deformity can occur in the pediatric and adolescent populations from multiple etiologies: congenital, traumatic, posttraumatic sequelae, oncologic, and infection. Correcting these deformities is important for many reasons. Ilizarov popularized external fixation to accomplish this task. Taylor expanded on this by designing an external fixator in 1994 with 6 telescoping struts that can be sequentially manipulated to achieve multiaxial correction of deformity without the need for hinges or operative frame alterations. This frame can be used to correct deformities in children and has shown good anatomic correction with minimal morbidity. The nature of the construct and length of treatment affects psychosocial factors that the surgeon and family must be aware of prior to treatment. An understanding of applications of the Taylor Spatial Frame gives orthopedic surgeons an extra tool to correct simple and complex deformities in pediatric and adolescent patients. Copyright 2012, SLACK Incorporated.

  8. Influence of velocity shear on the Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Guzdar, P.N.; Satyanarayana, P.; Huba, J.D.; Ossakow, S.L.

    1982-01-01

    The influence of a transverse velocity shear on the Rayleigh-Taylor instability is investigated. It is found that a sheared velocity flow can substantially reduce the growth rate of the Rayleigh-Taylor instability in short wavelength regime (i.e., kL>1 where L is the scale length of the density inhomogeneity), and causes the growth rate to maximize at kL<1.0. Applications of this result to ionospheric phenomena [equatorial spread F (ESF) and ionospheric plasma clouds] are discussed. In particular, the effect of shear could account for, at times, the 100's of km modulation observed on the bottomside of the ESF ionosphere and the km scale size wavelengths observed in barium cloud prompt striation phenomena

  9. Irregular wall roughness in turbulent Taylor-Couette flow

    Science.gov (United States)

    Berghout, Pieter; Zhu, Xiaojue; Verzicco, Roberto; Lohse, Detlef; Stevens, Richard

    2017-11-01

    Many wall bounded flows in nature, engineering and transport are affected by surface roughness. Often, this has adverse effects, e.g. drag increase leading to higher energy costs. A major difficulty is the infinite number of roughness geometries, which makes it impossible to systematically investigate all possibilities. Here we present Direct Numerical Simulations (DNS) of turbulent Taylor-Couette flow. We focus on the transitionally rough regime, in which both viscous and pressure forces contribute to the total wall stress. We investigate the effect of the mean roughness height and the effective slope on the roughness function, ΔU+ . Also, we present simulations of varying Ta (Re) numbers for a constant mean roughness height (kmean+). Alongside, we show the behavior of the large scale structures (e.g. plume ejection, Taylor rolls) and flow structures in the vicinity of the wall.

  10. Great Lakes Ice Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  11. Bias Correction with Jackknife, Bootstrap, and Taylor Series

    OpenAIRE

    Jiao, Jiantao; Han, Yanjun; Weissman, Tsachy

    2017-01-01

    We analyze the bias correction methods using jackknife, bootstrap, and Taylor series. We focus on the binomial model, and consider the problem of bias correction for estimating $f(p)$, where $f \\in C[0,1]$ is arbitrary. We characterize the supremum norm of the bias of general jackknife and bootstrap estimators for any continuous functions, and demonstrate the in delete-$d$ jackknife, different values of $d$ may lead to drastically different behavior in jackknife. We show that in the binomial ...

  12. Parametric modulation in the Taylor-Couette ferrofluid flow

    International Nuclear Information System (INIS)

    Singh, Jitender; Bajaj, Renu

    2008-01-01

    A parametric instability of the Taylor-Couette ferrofluid flow excited by a periodically oscillating magnetic field, has been investigated numerically. The Floquet analysis has been employed. It has been found that the modulation of the applied magnetic field affects the stability of the basic flow. The instability response has been found to be synchronous with respect to the frequency of periodically oscillating magnetic field.

  13. Interpreted Modernity. Weber and Taylor on Values and Modernity

    OpenAIRE

    Reckling, Falk

    2001-01-01

    The writings of Weber and Taylor have some strong affinities. Both start from the anthropological idea that man evaluates his position in the world and constitutes the social world by values. Their analyses of values aim at an understanding of those intersubjective meanings that have constituted western modernity. But, at the same time, their anthropological starting point leads to different interpretations of modernity. Historically, both argue that rationalization (as instrumental rationali...

  14. The Taylor relation in compression deformed Ge single crystals

    International Nuclear Information System (INIS)

    Nyilas, K; Ungar, T; Dupas, C; Martin, J L; Kruml, T

    2010-01-01

    Ge single crystals are deformed in compression at 850K and the same strain rate to various extents of strains. In each sample, the internal stress is measured through stress reduction tests and the dislocation densities by X-ray measurements. Data about these two parameters follow fairly well the Taylor-Saada relation, provided a correction term is added. It probably corresponds to dislocations which are seen by X-rays, though they do not contribute to crystal hardening.

  15. Taylor's Theorem: The Elusive "c" Is Not So Elusive

    Science.gov (United States)

    Kreminski, Richard

    2010-01-01

    For a suitably nice, real-valued function "f" defined on an open interval containing [a,b], f(b) can be expressed as p[subscript n](b) (the nth Taylor polynomial of f centered at a) plus an error term of the (Lagrange) form f[superscript (n+1)](c)(b-a)[superscript (n+1)]/(n+1)! for some c in (a,b). This article is for those who think that not…

  16. Firm-specific investment, sticky prices and the Taylor principle

    OpenAIRE

    Sveen, Tommy; Weinke, Lutz

    2005-01-01

    According to the Taylor principle a central bank should adjust the nominal interest rate by more than one-for-one in response to changes in current inflation. Most of the existing literature supports the view that by following this simple recommendation a central bank can avoid being a source of unnecessary fluctuations in economic activity. The present paper shows that this conclusion is not robust with respect to the modelling of capital accumulation. We use our insights to discuss the desi...

  17. Stochastic model of Rayleigh-Taylor turbulent mixing

    International Nuclear Information System (INIS)

    Abarzhi, S.I.; Cadjan, M.; Fedotov, S.

    2007-01-01

    We propose a stochastic model to describe the random character of the dissipation process in Rayleigh-Taylor turbulent mixing. The parameter alpha, used conventionally to characterize the mixing growth-rate, is not a universal constant and is very sensitive to the statistical properties of the dissipation. The ratio between the rates of momentum loss and momentum gain is the statistic invariant and a robust parameter to diagnose with or without turbulent diffusion accounted for

  18. Rayleigh-Taylor instability in an equal mass plasma

    Energy Technology Data Exchange (ETDEWEB)

    Adak, Ashish, E-mail: ashish-adak@yahoo.com [Department of Instrumentation Science, Jadavpur University, Kolkata 700 032 (India); Ghosh, Samiran, E-mail: sran-g@yahoo.com [Department of Applied Mathematics, University of Calcutta 92, Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Chakrabarti, Nikhil, E-mail: nikhil.chakrabarti@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

    2014-09-15

    The Rayleigh-Taylor (RT) instability in an inhomogeneous pair-ion plasma has been analyzed. Considering two fluid model for two species of ions (positive and negative), we obtain the possibility of the existence of RT instability. The growth rate of the RT instability as usual depends on gravity and density gradient scale length. The results are discussed in context of pair-ion plasma experiments.

  19. Rayleigh-Taylor instability in a visco-plastic fluid

    International Nuclear Information System (INIS)

    Demianov, A Yu; Doludenko, A N; Son, E E; Inogamov, N A

    2010-01-01

    The Rayleigh-Taylor and Richtmyer-Meshkov instabilities of a visco-plastic fluid are discussed. The Bingham model is used as an effective rheological model which takes into account plastic effects. For the purposes of numerical simulation a one-mode disturbance of the contact surface between two fluids is considered. The main goal of this work is to construct numerical 2D and 3D models and to obtain the relationship between yield stress and the development of instability.

  20. Rayleigh-Taylor instability in a visco-plastic fluid

    Science.gov (United States)

    Demianov, A. Yu; Doludenko, A. N.; Inogamov, N. A.; Son, E. E.

    2010-12-01

    The Rayleigh-Taylor and Richtmyer-Meshkov instabilities of a visco-plastic fluid are discussed. The Bingham model is used as an effective rheological model which takes into account plastic effects. For the purposes of numerical simulation a one-mode disturbance of the contact surface between two fluids is considered. The main goal of this work is to construct numerical 2D and 3D models and to obtain the relationship between yield stress and the development of instability.

  1. Boundary effects and the onset of Taylor vortices

    Science.gov (United States)

    Rucklidge, A. M.; Champneys, A. R.

    2004-05-01

    It is well established that the onset of spatially periodic vortex states in the Taylor-Couette flow between rotating cylinders occurs at the value of Reynolds number predicted by local bifurcation theory. However, the symmetry breaking induced by the top and bottom plates means that the true situation should be a disconnected pitchfork. Indeed, experiments have shown that the fold on the disconnected branch can occur at more than double the Reynolds number of onset. This leads to an apparent contradiction: why should Taylor vortices set in so sharply at the Reynolds number predicted by the symmetric theory, given such large symmetry-breaking effects caused by the boundary conditions? This paper offers a generic explanation. The details are worked out using a Swift-Hohenberg pattern formation model that shares the same qualitative features as the Taylor-Couette flow. Onset occurs via a wall mode whose exponential tail penetrates further into the bulk of the domain as the driving parameter increases. In a large domain of length L, we show that the wall mode creates significant amplitude in the centre at parameter values that are O( L-2) away from the value of onset in the problem with ideal boundary conditions. We explain this as being due to a Hamiltonian Hopf bifurcation in space, which occurs at the same parameter value as the pitchfork bifurcation of the temporal dynamics. The disconnected anomalous branch remains O(1) away from the onset parameter since it does not arise as a bifurcation from the wall mode.

  2. Ruptured peroneal aneurysm after infrapopliteal prosthetic bypass with Taylor patch

    Directory of Open Access Journals (Sweden)

    Florian Enzmann

    Full Text Available Introduction: A 45-year-old mailman underwent an implantation of a femoro-peroneal polytetrafluoroethylene (PTFE bypass with a distal Taylor patch six years prior to admission after two failed autologous reconstructions and extensive fasciotomy. The initial pathology was an acute ischemia due to popliteal entrapment with subsequent popliteal thrombectomy. Report: The patient was examined because of pain, reduction of walking distance and development of a palpable mass at the medial fasciotomy site. A 6-cm pseudoaneurysm with complete disruption of the suture line of the vein patch was discovered and resected. Arterial continuity with a vein interposition graft was established using non-reversed cephalic vein. Conclusion: The etiology of the aneurysm is not entirely clear. One may argue that the fourth revascularization could have been performed with an arm vein instead of a prosthetic graft with the probability of a better long term patency in a young patient. 15 months after the procedure the bypass is patent and the patient is without any symptoms. This complication of a Taylor patch has not been reported before. Keywords: Taylor patch, Pseudoaneurysm, Infrapopliteal bypass

  3. Rayleigh-Taylor instability of cylindrical jets with radial motion

    International Nuclear Information System (INIS)

    Chen, X.M.; Schrock, V.E.; Peterson, P.F.

    1997-01-01

    Rayleigh-Taylor instability of an interface between fluids with different densities subjected to acceleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of instability for a cylindrical surface with radial motions. The results of the analysis show that, like the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed. (orig.)

  4. Taylor bubbles at high viscosity ratios: experiments and numerical simulations

    Science.gov (United States)

    Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar

    2015-11-01

    The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor bubble rising in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rising and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor bubble shape and rise velocity are presented, together with numerical results for the dynamics of the bubbles. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  5. Numerical study of Taylor bubbles with adaptive unstructured meshes

    Science.gov (United States)

    Xie, Zhihua; Pavlidis, Dimitrios; Percival, James; Pain, Chris; Matar, Omar; Hasan, Abbas; Azzopardi, Barry

    2014-11-01

    The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube. This type of bubble flow regime often occurs in gas-liquid slug flows in many industrial applications, including oil-and-gas production, chemical and nuclear reactors, and heat exchangers. The objective of this study is to investigate the fluid dynamics of Taylor bubbles rising in a vertical pipe filled with oils of extremely high viscosity (mimicking the ``heavy oils'' found in the oil-and-gas industry). A modelling and simulation framework is presented here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rise and reduce the computational effort without sacrificing accuracy. The numerical framework consists of a mixed control-volume and finite-element formulation, a ``volume of fluid''-type method for the interface capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Numerical examples of some benchmark tests and the dynamics of Taylor bubbles are presented to show the capability of this method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  6. Effective pine bark composting with the Dome Aeration Technology

    International Nuclear Information System (INIS)

    Trois, Cristina; Polster, Andreas

    2007-01-01

    In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treatment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical-biological waste treatment. In: Proceedings of the 7th International Waste Management and Landfill Symposium, Cagliari, 4-8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical-biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vorster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3-4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the material were taken. The process

  7. Experimental Analysis of Sublimation Dynamics for Buried Glacier Ice in Beacon Valley, Antarctica

    Science.gov (United States)

    Ehrenfeucht, S.; Dennis, D. P.; Marchant, D. R.

    2017-12-01

    The age of the oldest known buried ice in Beacon Valley, McMurdo Dry Valleys (MDV) Antarctica is a topic of active debate due to its implications for the stability of the East Antarctic Ice Sheet. Published age estimates range from as young as 300 ka to as old as 8.1 Ma. In the upland MDV, ablation occurs predominantly via sublimation. The relict ice in question (ancient ice from Taylor Glacier) lies buried beneath a thin ( 30-70 cm) layer of sublimation till, which forms as a lag deposit as underlying debris-rich ice sublimes. As the ice sublimates, the debris held within the ice accumulates slowly on the surface, creating a porous boundary between the buried-ice surface and the atmosphere, which in turn influences gas exchange between the ice and the atmosphere. Additionally, englacial debris adds several salt species that are ultimately concentrated on the ice surface. It is well documented the rate of ice sublimation varies as a function of overlying till thickness. However, the rate-limiting dynamics under varying environmental conditions, including the threshold thicknesses at which sublimation is strongly retarded, are not yet defined. To better understand the relationships between sublimation rate, till thickness, and long-term surface evolution, we build on previous studies by Lamp and Marchant (2017) and evaluate the role of till thickness as a control on ice loss in an environmental chamber capable of replicating the extreme cold desert conditions observed in the MDV. Previous work has shown that this relationship exhibits exponential decay behavior, with sublimation rate significantly dampened under less than 10 cm of till. In our experiments we pay particular attention to the effect of the first several cm of till in order to quantify the dynamics that govern the transition from bare ice to debris-covered ice. We also examine this transition for various forms of glacier ice, including ice with various salt species.

  8. Reconnaissance study of the Taylor Mountains pluton, southwestern Alaska

    Science.gov (United States)

    Hudson, Travis L.; Miller, Marti L.; Klimasauskas, Edward P.; Layer, Paul W.

    2010-01-01

    The Taylor Mountains pluton is a Late Cretaceous to early Tertiary (median age 65 + or ? 2 Ma) epizonal, composite biotite granite stock located about 235 km (145 mi) northeast of Dillingham in southwestern Alaska. This 30 km2 (12 mi2) pluton has sharp and discordant contacts with hornfels that developed in Upper Cretaceous clastic sedimentary rocks of the Kuskokwim Group. The three intrusive phases in the Taylor Mountains pluton, in order of emplacement, are (1) porphyritic granite containing large K-feldspar phenocrysts in a coarse-grained groundmass, (2) porphyritic granite containing large K-feldspar and smaller, but still coarse, plagioclase, quartz, and biotite phenocrysts in a fine-grained groundmass, and (3) fine-grained, leucocratic, equigranular granite. The porphyritic granites have different emplacement histories, but similar compositions; averages are 69.43 percent SiO2, 1.62 percent CaO, 5.23 percent FeO+MgO, 3.11 percent Na2O, and 4.50 percent K2O. The fine-grained, equigranular granite is distinctly felsic compared to porphyritic granite; it averages 75.3 percent SiO2, 0.49 percent CaO, 1.52 percent FeO+MgO, 3.31 percent Na2O, and 4.87 percent K2O. Many trace elements including Ni, Cr, Sc, V, Ba, Sr, Zr, Y, Nb, La, Ce, Th, and Nd are strongly depleted in fine-grained equigranular granite. Trace elements are not highly enriched in any of the granites. Known hydrothermal alteration is limited to one tourmaline-quartz replacement zone in porphyritic granite. Mineral deposits in the Taylor Mountains area are primarily placer gold (plus wolframite, cassiterite, and cinnabar); sources for these likely include scattered veins in hornfels peripheral to the Taylor Mountain pluton. The granite magmas that formed the Taylor Mountains pluton are thought to represent melted continental crust that possibly formed in response to high heat flow in the waning stage of Late Cretaceous subduction beneath interior Alaska.

  9. The decorative program of the domes and area under the domes in the church of the monastery Resava

    Directory of Open Access Journals (Sweden)

    Prolović Jadranka

    2008-01-01

    Full Text Available Because the dome is interpreted as a symbol of the heavens, it is reserved for heavenly subjects. The calotte of the dome is seen as a vault of heaven or 'heaven in the heavens' and, as such, as the 'house of Christ'. As the commentator in the 19th century reports, the image of Christ Pantokrator was once located at the zenith of the central dome of Resava. The preserved scenes and figures below the dome, specifically the heavenly liturgy and the prophets, confirm the original existence of this image. Together they build an iconology that was very widespread in late Byzantine art. The composition of the central dome of Resava resembles in its complete appearance, supported by some particularities, the central dome of Ravanica, which served as a model for the artists of Resava. One can find close parallels for the decoration of the side domes in Ravanica. The similar arrangement of heavenly powers in the tambours of the domes in Ravanica and Resava indicate that, like in Ravanica, Christ Emmanuel, the Age of Days, the Mother of God and the Archangel Michael could have been depicted in the zenith of the side domes of Resava. This type of decorative scheme in side domes is common in late Byzantine monumental painting. The remaining fragments with images of angels as deacons positioned in the ring around the zenith of the central dome show that the Heavenly Liturgy was depicted here, specifically the Large Entrance which, aside from the communion, was the only part of the liturgy visible to the faithful. In Resava, the Heavenly Liturgy is completed by the images of crowds of angels, which are portrayed in the tambours of the side domes. The liturgical hymns that accompany these images of angels confirm this order. The rendering of orders of angels in the tambours of the side domes in Resava comply with the traditional program in which these heavenly beings - who being closest to God, who were his first creations and the only to whom a look in the

  10. DomeHaz, a Global Hazards Database: Understanding Cyclic Dome-forming Eruptions, Contributions to Hazard Assessments, and Potential for Future Use and Integration with Existing Cyberinfrastructure

    Science.gov (United States)

    Ogburn, S. E.; Calder, E.; Loughlin, S.

    2013-12-01

    Dome-forming eruptions can extend for significant periods of time and can be dangerous; nearly all dome-forming eruptions have been associated with some level of explosive activity. Large Plinian explosions with a VEI ≥ 4 sometimes occur in association with dome-forming eruptions. Many of the most significant volcanic events of recent history are in this category. The 1902-1905 eruption of Mt. Pelée, Martinique; the 1980-1986 eruption of Mount St. Helens, USA; and the 1991 eruption of Mt. Pinatubo, Philippines all demonstrate the destructive power of VEI ≥ 4 dome-forming eruptions. Global historical analysis is a powerful tool for decision-making as well as for scientific discovery. In the absence of monitoring data or a knowledge of a volcano's eruptive history, global analysis can provide a method of understanding what might be expected based on similar eruptions. This study investigates the relationship between large explosive eruptions and lava dome growth and develops DomeHaz, a global database of dome-forming eruptions from 1000 AD to present. It is currently hosted on VHub (https://vhub.org/groups/domedatabase/), a community cyberinfrastructure for sharing data, collaborating, and modeling. DomeHaz contains information about 367 dome-forming episodes, including duration of dome growth, duration of pauses in extrusion, extrusion rates, and the timing and magnitude of associated explosions. Data sources include the The Smithsonian Institution Global Volcanism Program (GVP), Bulletin of the Global Volcanism Network, and all relevant published review papers, research papers, and reports. This database builds upon previous work (e.g Newhall and Melson, 1983) in light of newly available data for lava dome eruptions. There have been 46 new dome-forming eruptions, 13 eruptions that continued past 1982, 151 new dome-growth episodes, and 8 VEI ≥ 4 events since Newhall and Melson's work in 1983. Analysis using DomeHaz provides useful information regarding the

  11. Repair of manufacturing defects in the armor of plasma facing units of the ITER Divertor Dome

    International Nuclear Information System (INIS)

    Litunovsky, Nikolay; Alekseenko, Evgeny; Kuznetsov, Vladimir; Lyanzberg, Dmitriy; Makhankov, Aleksey; Rulev, Roman

    2013-01-01

    Highlights: • Sporadic manufacturing defects in ITER Divertor Dome PFUs may be repaired. • We have developed a repair technique for ITER Divertor Dome PFUs. • Armor repair technique for ITER Divertor Dome PFUs is successfully tested. -- Abstract: The paper describes the repair procedure developed for removal of manufacturing defects occurring sporadically during armoring of plasma facing units (PFUs) of the ITER Divertor Dome. Availability of armor repair technique is prescribed by the procurement arrangement for the ITER Divertor Dome concluded in 2009 between the ITER Organization and the ITER Domestic Agency of Russia. The paper presents the detailed description of the procedure, data on its effect on the joints of the rest part of the armor and on the grain structure of the PFU heat sink. The results of thermocycling of large-scale Dome PFU mock-ups manufactured with demonstration of armor repair are also given

  12. Conceptual model for regional radionuclide transport from a salt dome repository: a technical memorandum

    International Nuclear Information System (INIS)

    Kier, R.S.; Showalter, P.A.; Dettinger, M.D.

    1980-01-01

    Disposal of high-level radioactive wastes is a major environmental problem influencing further development of nuclear energy in this country. Salt domes in the Gulf Coast Basin are being investigated as repository sites. A major concern is geologic and hydrologic stability of candidate domes and potential transport of radionuclides by groundwater to the biosphere prior to their degradation to harmless levels of activity. This report conceptualizes a regional geohydrologic model for transport of radionuclides from a salt dome repository. The model considers transport pathways and the physical and chemical changes that would occur through time prior to the radionuclides reaching the biosphere. Necessary, but unknown inputs to the regional model involve entry and movement of fluids through the repository dome and across the dome-country rock interface and the effect on the dome and surrounding strata of heat generated by the radioactive wastes

  13. Repair of manufacturing defects in the armor of plasma facing units of the ITER Divertor Dome

    Energy Technology Data Exchange (ETDEWEB)

    Litunovsky, Nikolay, E-mail: nlitunovsky@sintez.niiefa.spb.su; Alekseenko, Evgeny; Kuznetsov, Vladimir; Lyanzberg, Dmitriy; Makhankov, Aleksey; Rulev, Roman

    2013-10-15

    Highlights: • Sporadic manufacturing defects in ITER Divertor Dome PFUs may be repaired. • We have developed a repair technique for ITER Divertor Dome PFUs. • Armor repair technique for ITER Divertor Dome PFUs is successfully tested. -- Abstract: The paper describes the repair procedure developed for removal of manufacturing defects occurring sporadically during armoring of plasma facing units (PFUs) of the ITER Divertor Dome. Availability of armor repair technique is prescribed by the procurement arrangement for the ITER Divertor Dome concluded in 2009 between the ITER Organization and the ITER Domestic Agency of Russia. The paper presents the detailed description of the procedure, data on its effect on the joints of the rest part of the armor and on the grain structure of the PFU heat sink. The results of thermocycling of large-scale Dome PFU mock-ups manufactured with demonstration of armor repair are also given.

  14. The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona

    Science.gov (United States)

    Fuis, Gary S.

    1996-01-01

    The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

  15. Rapid changes in ice core gas records - Part 1: On the accuracy of methane synchronisation of ice cores

    Science.gov (United States)

    Köhler, P.

    2010-08-01

    Methane synchronisation is a concept to align ice core records during rapid climate changes of the Dansgaard/Oeschger (D/O) events onto a common age scale. However, atmospheric gases are recorded in ice cores with a log-normal-shaped age distribution probability density function, whose exact shape depends mainly on the accumulation rate on the drilling site. This age distribution effectively shifts the mid-transition points of rapid changes in CH4 measured in situ in ice by about 58% of the width of the age distribution with respect to the atmospheric signal. A minimum dating uncertainty, or artefact, in the CH4 synchronisation is therefore embedded in the concept itself, which was not accounted for in previous error estimates. This synchronisation artefact between Greenland and Antarctic ice cores is for GRIP and Byrd less than 40 years, well within the dating uncertainty of CH4, and therefore does not calls the overall concept of the bipolar seesaw into question. However, if the EPICA Dome C ice core is aligned via CH4 to NGRIP this synchronisation artefact is in the most recent unified ice core age scale (Lemieux-Dudon et al., 2010) for LGM climate conditions of the order of three centuries and might need consideration in future gas chronologies.

  16. Light, shadows and surface characteristics: the multispectral Portable Light Dome

    Science.gov (United States)

    Watteeuw, Lieve; Hameeuw, Hendrik; Vandermeulen, Bruno; Van der Perre, Athena; Boschloos, Vanessa; Delvaux, Luc; Proesmans, Marc; Van Bos, Marina; Van Gool, Luc

    2016-11-01

    A multispectral, multidirectional, portable and dome-shaped acquisition system is developed within the framework of the research projects RICH (KU Leuven) and EES (RMAH, Brussels) in collaboration with the ESAT-VISICS research group (KU Leuven). The multispectral Portable Light Dome (MS PLD) consists of a hemispherical structure, an overhead camera and LEDs emitting in five parts of the electromagnetic spectrum regularly covering the dome's inside surface. With the associated software solution, virtual relighting and enhancements can be applied in a real-time, interactive manner. The system extracts genuine 3D and shading information based on a photometric stereo algorithm. This innovative approach allows for instantaneous alternations between the computations in the infrared, red, green, blue and ultraviolet spectra. The MS PLD system has been tested for research ranging from medieval manuscript illuminations to ancient Egyptian artefacts. Preliminary results have shown that it documents and measures the 3D surface structure of objects, re-visualises underdrawings, faded pigments and inscriptions, and examines the MS results in combination with the actual relief characteristics of the physical object. Newly developed features are reflection maps and histograms, analytic visualisations of the reflection properties of all separate LEDs or selected areas. In its capacity as imaging technology, the system acts as a tool for the analysis of surface materials (e.g. identification of blue pigments, gold and metallic surfaces). Besides offering support in answering questions of attribution and monitoring changes and decay of materials, the PLD also contributes to the identification of materials, all essential factors when making decisions in the conservation protocol.

  17. Dead-ice environments

    DEFF Research Database (Denmark)

    Krüger, Johannes; Kjær, Kurt H.; Schomacker, Anders

    2010-01-01

    glacier environment. The scientific challenges are to answer the key questions. What are the conditions for dead-ice formation? From which sources does the sediment cover originate? Which melting and reworking processes act in the ice-cored moraines? What is the rate of de-icing in the ice-cored moraines...

  18. Longitudinal biases in the Seychelles Dome simulated by 35 ocean-atmosphere coupled general circulation models

    Science.gov (United States)

    Nagura, Motoki; Sasaki, Wataru; Tozuka, Tomoki; Luo, Jing-Jia; Behera, Swadhin K.; Yamagata, Toshio

    2013-02-01

    Seychelles Dome refers to the shallow climatological thermocline in the southwestern Indian Ocean, where ocean wave dynamics efficiently affect sea surface temperature, allowing sea surface temperature anomalies to be predicted up to 1-2 years in advance. Accurate reproduction of the dome by ocean-atmosphere coupled general circulation models (CGCMs) is essential for successful seasonal predictions in the Indian Ocean. This study examines the Seychelles Dome as simulated by 35 CGCMs, including models used in phase five of the Coupled Model Intercomparison Project (CMIP5). Among the 35 CGCMs, 14 models erroneously produce an upwelling dome in the eastern half of the basin whereas the observed Seychelles Dome is located in the southwestern tropical Indian Ocean. The annual mean Ekman pumping velocity in these models is found to be almost zero in the southern off-equatorial region. This result is inconsistent with observations, in which Ekman upwelling acts as the main cause of the Seychelles Dome. In the models reproducing an eastward-displaced dome, easterly biases are prominent along the equator in boreal summer and fall, which result in shallow thermocline biases along the Java and Sumatra coasts via Kelvin wave dynamics and a spurious upwelling dome in the region. Compared to the CMIP3 models, the CMIP5 models are even worse in simulating the dome longitudes.

  19. Draft environmental assessment: Vacherie Dome site, Louisiana. Nuclear Waste Policy Act (Section 112)

    International Nuclear Information System (INIS)

    1984-12-01

    In February 1983, the US Department of Energy (DOE) identified the Vacherie dome in Louisiana as one of nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Vacherie dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for Nuclear Waste Repositories. These evaluations are reported in this draft environmental assessment (EA), which is being issued for public review and comment. The DOE findings and determinations that are based on these evaluations are preliminary and subject to public review and comment. A final EA will be prepared after considering the comments received. On the basis of the evaluations contained in this draft EA, the DOE has found that the Vacherie dome site is not disqualified under the guidelines. The site is contained in the Gulf Interior Region of the Gulf Coastal Plain, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains two other potentially acceptable sites - the Cypress Creek dome site and the Richton dome site. Although the Vacherie dome site appears to be suitable for site characterization, the DOE has concluded that the Richton dome site is the preferred site in the Gulf Interior Region. On the basis of these findings, the DOE is proposing to nominate the Richton dome site rather than the Vacherie dome site as one of the five sites suitable for characterization

  20. A Planetarium Inside Your Office: Virtual Reality in the Dome Production Pipeline

    Science.gov (United States)

    Summers, Frank

    2018-01-01

    Producing astronomy visualization sequences for a planetarium without ready access to a dome is a distorted geometric challenge. Fortunately, one can now use virtual reality (VR) to simulate a dome environment without ever leaving one's office chair. The VR dome experience has proven to be a more than suitable pre-visualization method that requires only modest amounts of processing beyond the standard production pipeline. It also provides a crucial testbed for identifying, testing, and fixing the visual constraints and artifacts that arise in a spherical presentation environment. Topics adreesed here will include rendering, geometric projection, movie encoding, software playback, and hardware setup for a virtual dome using VR headsets.

  1. Numerical analysis of pressure and porosity evolution in lava domes during periodic degassing conditions

    Science.gov (United States)

    Hyman, D.; Bursik, M. I.; Pitman, E. B.

    2017-12-01

    The collapse or explosive breakup of growing and degassing lava domes presents a significant hazard due to the generation of dense, mobile pyroclastic flows as well as the wide dispersal of dense ballistic blocks. Lava dome stability is in large part governed by the balance of transport and storage of gas within the pore space. Because pore pressurization reduces the effective stress within a dome, the transient distribution of elevated gas pressure is critically important to understanding dome break up. We combine mathematical and numerical analyses to gain a better understanding of the temporal variation in gas flow and storage within the dome system. In doing so, we develop and analyze new governing equations describing nonlinear gas pressure diffusion in a deforming dome with an evolving porosity field. By relating porosity, permeability, and pressure, we show that the flux of gas through a dome is highly sensitive to the porosity distribution and viscosity of the lava, as well as the timescale and magnitude of the gas supply. The numerical results suggest that the diffusion of pressure and porosity variations play an integral role in the cyclic growth and destruction of small domes.The nearly continuous cycles of lava dome growth, pressurization, and failure that have characterized the last two decades of eruptive history at Volcán Popocatépetl, Mexico provide excellent natural data with which to compare new models of transient dome pressurization. At Popocatépetl, periodic pressure increases brought on by changes in gas supply into the base of the dome may play a role in its cyclic growth and destruction behavior. We compare our model of cyclic pressurization with lava dome survival data from Popocatépetl. We show that transient changes in pore pressure explain how small lava domes evolve to a state of criticality before explosion or collapse. Additionally, numerical analyses presented here suggest that short-term oscillations cannot arise within the dome

  2. Spatial variations of growth within domes having different patterns of principal growth directions

    Directory of Open Access Journals (Sweden)

    Jerzy Nakielski

    2014-01-01

    Full Text Available Growth rate variations for two paraboloidal domes: A and B, identical when seen from the outside but differing in the internal pattern of principal growth directions, were modeled by means of the growth tensor and a natural coordinate system. In dome A periclinal trajectories in the axial plane were given by confocal parabolas (as in a tunical dome, in dome B by parabolas converging to the vertex (as in a dome without a tunica. Accordingly, two natural coordinate systems, namely paraboloidal for A and convergent parabolic for B, were used. In both cases, the rate of growth in area on the surfaces of domes was assumed to be isotropic and identical in corresponding points. It appears that distributions of growth rates within domes A and B are similar in their peripheral and central parts and different only in their distal regions. In the latter, growth rates are relatively large; the maximum relative rate of growth in volume is around the geometric focus in dome A, and on the surface around the vertex in dome B.

  3. A Scalable and Modular Dome Illumination System for Scientific Microphotography on a Budget.

    Directory of Open Access Journals (Sweden)

    Ricardo Kawada

    Full Text Available A scalable and modular LED illumination dome for microscopic scientific photography is described and illustrated, and methods for constructing such a dome are detailed. Dome illumination for insect specimens has become standard practice across the field of insect systematics, but many dome designs remain expensive and inflexible with respect to new LED technology. Further, a one-size-fits-all dome cannot accommodate the large breadth of insect size encountered in nature, forcing the photographer to adapt, in some cases, to a less than ideal dome design. The dome described here is scalable, as it is based on a isodecahedron, and the template for the dome is available as a downloaded file from the internet that can be printed on any printer, on the photographer's choice of media. As a result, a photographer can afford, using this design, to produce a series of domes of various sizes and materials, and LED ring lights of various sizes and color temperatures, depending on the need.

  4. Draft environmental assessment: Cypress Creek Dome site, Mississippi. Nuclear Waste Policy Act (Section 112)

    International Nuclear Information System (INIS)

    1984-12-01

    In February 1983, the US Department of Energy (DOE) identified the Cypress Creek dome site in Mississippi as one of nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Cypress Creek dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for Nuclear Waste Repositories. These evaluations are reported in this draft environmental assessment (EA), which is being issued for public review and comment. The DOE findings and determinations that are based on these evaluations are preliminary and subject to public review and comment. A final EA will be prepared after considering the comments received. On the basis of the evaluations contained in this draft EA, the DOE has found that the Cypress Creek dome site is not disqualified under the guidelines. The site is contained in the Gulf Interior Region of the Gulf Coastal Plain, which is one of five distinct geohydrologic settings considered for the first repository. This setting contains two other potentially acceptable sites - the Richton dome site and the Vacherie dome site. Although the Cypress Creek dome site appears to be suitable for site characterization, the DOE has concluded that the Richton dome site is the preferred site in the Gulf Interior Region and is proposing to nominate the Richton dome site rather than the Cypress Creek dome site as one of the three sites suitable for characterization

  5. Rate of ice accumulation during ice storms

    Energy Technology Data Exchange (ETDEWEB)

    Feknous, N. [SNC-Lavalin, Montreal, PQ (Canada); Chouinard, L. [McGill Univ., Montreal, PQ (Canada); Sabourin, G. [Hydro-Quebec, Montreal, PQ (Canada)

    2005-07-01

    The rate of glaze ice accumulation is the result of a complex process dependent on numerous meteorological and physical factors. The aim of this paper was to estimate the distribution rate of glaze ice accumulation on conductors in southern Quebec for use in the design of mechanical and electrical de-icing devices. The analysis was based on direct observations of ice accumulation collected on passive ice meters. The historical database of Hydro-Quebec, which contains observations at over 140 stations over period of 25 years, was used to compute accumulation rates. Data was processed so that each glaze ice event was numbered in a chronological sequence. Each event consisted of the time series of ice accumulations on each of the 8 cylinders of the ice meters, as well as on 5 of its surfaces. Observed rates were converted to represent the average ice on a 30 mm diameter conductor at 30 m above ground with a span of 300 m. Observations were corrected to account for the water content of the glaze ice as evidenced by the presence of icicles. Results indicated that despite significant spatial variations in the expected severity of ice storms as a function of location, the distribution function for rates of accumulation were fairly similar and could be assumed to be independent of location. It was concluded that the observations from several sites could be combined in order to obtain better estimates of the distribution of hourly rates of ice accumulation. However, the rates were highly variable. For de-icing strategies, it was suggested that average accumulation rates over 12 hour periods were preferable, and that analyses should be performed for other time intervals to account for the variability in ice accumulation rates over time. In addition, accumulation rates did not appear to be highly correlated with average wind speed for maximum hourly accumulation rates. 3 refs., 2 tabs., 10 figs.

  6. Bright and durable field emission source derived from refractory taylor cones

    Science.gov (United States)

    Hirsch, Gregory

    2016-12-20

    A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tip end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.

  7. Shear flow stabilization of the hydromagnetic Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Roderick, N.F.; Shumlak, U.; Douglas, M.; Peterkin, R.E. Jr.; Ruden, E.

    1997-01-01

    Numerical simulations have indicated that shear flow may help stabilize the hydromagnetic Rayleigh-Taylor instability in imploding plasma z-pinches. A simple extension to a model presented in Chandrasekhar has been developed to study the linear stability of incompressible plasma subjected to both a shear flow and acceleration. The model has been used to investigate the stability plasma implosion schemes using externally imposed velocity shear which develops from the plasma flow itself. Specific parameters were chosen to represent plasma implosions driven by the Saturn and PBFA-Z, pulsed power generators at Sandia National Laboratories. Results indicate a high shear is necessary to stabilize the z-pinch implosions studied

  8. Rayleigh-Taylor instability in accelerated elastic-solid slabs

    Science.gov (United States)

    Piriz, S. A.; Piriz, A. R.; Tahir, N. A.

    2017-12-01

    We develop the linear theory for the asymptotic growth of the incompressible Rayleigh-Taylor instability of an accelerated solid slab of density ρ2, shear modulus G , and thickness h , placed over a semi-infinite ideal fluid of density ρ110.1007/s000330050121] to arbitrary values of AT and unveil the singular feature of an instability threshold below which the slab is stable for any perturbation wavelength. As a consequence, an accelerated elastic-solid slab is stable if ρ2g h /G ≤2 (1 -AT) /AT .

  9. Identità e riconoscimento in Charles Taylor

    Directory of Open Access Journals (Sweden)

    Francesca Caputo

    2013-06-01

    Full Text Available The model of the politic of difference, proposed by Charles Taylor, in the wake of a conception of liberalism ‘hospitable’, unfolds in a journey aimed to comply with the ontological dimensions of the dignity of different cultures, of cultural traditions and ways of life. Being a self, constructed in terms of dialogue and dialectic of mutual recognition between cultures, refers, in the Charles Taylor’s reflection, to the safeguarding of single, intersubjective or common meanings of specific social, moral, narrative spaces.

  10. The Psychological Concepts in Taylor Swift's "Blank Space"

    OpenAIRE

    Anindhita, Novia Putri

    2016-01-01

    “Blank Space” is a song that is sung by a singer, Taylor Swift. The lyrics tell about the lonely woman who dates a lot but always fails to manage her relationship. However, it does not make her worry to start a new relationship. The purpose of this study is to analyze the elements of the poetry in the lyrics and to show the readers the psychological contents as portrayed in the music video. The study uses intrinsic and extrinsic theories to analyze the data and library research to compile the...

  11. Statistical approach of weakly nonlinear ablative Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Garnier, J.; Masse, L.

    2005-01-01

    A weakly nonlinear model is proposed for the Rayleigh-Taylor instability in presence of ablation and thermal transport. The nonlinear effects for a single-mode disturbance are computed, included the nonlinear correction to the exponential growth of the fundamental modulation. Mode coupling in the spectrum of a multimode disturbance is thoroughly analyzed by a statistical approach. The exponential growth of the linear regime is shown to be reduced by the nonlinear mode coupling. The saturation amplitude is around 0.1λ for long wavelengths, but higher for short instable wavelengths in the ablative regime

  12. Taylor-series method for four-nucleon wave functions

    International Nuclear Information System (INIS)

    Sandulescu, A.; Tarnoveanu, I.; Rizea, M.

    1977-09-01

    Taylor-series method for transforming the infinite or finite well two-nucleon wave functions from individual coordinates to relative and c.m. coordinates, by expanding the single particle shell model wave functions around c.m. of the system, is generalized to four-nucleon wave functions. Also the connections with the Talmi-Moshinsky method for two and four harmonic oscillator wave functions are deduced. For both methods Fortran IV programs for the expansion coefficients have been written and the equivalence of corresponding expressions numerically proved. (author)

  13. Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

    International Nuclear Information System (INIS)

    Lau, Yue Ying; Gilgenbach, Ronald

    2013-01-01

    Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed

  14. On Taylor-Series Approximations of Residual Stress

    Science.gov (United States)

    Pruett, C. David

    1999-01-01

    Although subgrid-scale models of similarity type are insufficiently dissipative for practical applications to large-eddy simulation, in recently published a priori analyses, they perform remarkably well in the sense of correlating highly against exact residual stresses. Here, Taylor-series expansions of residual stress are exploited to explain the observed behavior and "success" of similarity models. Until very recently, little attention has been given to issues related to the convergence of such expansions. Here, we re-express the convergence criterion of Vasilyev [J. Comput. Phys., 146 (1998)] in terms of the transfer function and the wavenumber cutoff of the grid filter.

  15. Lattice QCD for Baryon Rich Matter – Beyond Taylor Expansions

    Energy Technology Data Exchange (ETDEWEB)

    Bornyakov, V. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Boyda, D. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Goy, V. [School of Natural Sciences, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Molochkov, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Nakamura, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka, 567-0047 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako 351-0198 (Japan); Nikolaev, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Zakharov, V.I. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Moscow Inst Phys & Technol, Dolgoprudny, Moscow Region, 141700 (Russian Federation)

    2016-12-15

    We discuss our study for exploring the QCD phase diagram based on the lattice QCD. To go beyond the Taylor expansion and to reach higher density regions, we employ the canonical approach. In order to produce lattice data which meet experimental situation as much as possible, we propose a canonical approach with the charge and baryon number. We present our lattice QCD GPU code for this project which employs the clover improved Wilson fermions and Iwasaki gauge action to investigate pure imaginary chemical potential.

  16. Lattice QCD for Baryon Rich Matter – Beyond Taylor Expansions

    International Nuclear Information System (INIS)

    Bornyakov, V.; Boyda, D.; Goy, V.; Molochkov, A.; Nakamura, A.; Nikolaev, A.; Zakharov, V.I.

    2016-01-01

    We discuss our study for exploring the QCD phase diagram based on the lattice QCD. To go beyond the Taylor expansion and to reach higher density regions, we employ the canonical approach. In order to produce lattice data which meet experimental situation as much as possible, we propose a canonical approach with the charge and baryon number. We present our lattice QCD GPU code for this project which employs the clover improved Wilson fermions and Iwasaki gauge action to investigate pure imaginary chemical potential.

  17. Hydromagnetic Rayleigh-Taylor instability in cylindrical implosions

    International Nuclear Information System (INIS)

    Hwang, C.S.; Roderick, N.F.; Wu, M.W.

    1986-01-01

    Rayleigh-Taylor Instability in the (r,Θ) plane has been solved by the variational approach. Results are compared to the analytical solutions of two-region and three-region problems at the infinite radius. They show the magnetic stabilization effect. Growth rates in this plane are decreased by the effects of plasma shell thickness, plasma shell radius, magnetic tension, magnetic diffusion and finite density gradient of the plasma magnetic field interface. The most unstable mode number decreases when the radius of the plasma shell decreases

  18. Circulation of electrolyte in an electrochemical cell, using Taylor vortices

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, J D

    1990-05-30

    In an electrochemical cell for decomposition of organic waste liquids having an anode compartment and a cathode compartment separated by a porous pot, the anode is driven by a shaft having an axial passage extending from an upper inlet in the vicinity of the liquid level to a lower outlet adjacent a turbine. The rotating anode produces Taylor vortices in annular space and liquid is drawn from layer through passage and emerges to contact the anode. In one use, organic solvent such as tributyl phosphate/odourless kerosene is destroyed. Fresh solvent is added through an inlet. A helical cooler may also be provided. (author).

  19. Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Yue Ying [University of Michigan, Ann Arbor, MI (United States); Gilgenbach, Ronald [University of Michigan, Ann Arbor, MI (United States)

    2013-07-07

    Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed.

  20. Preliminary study of Rayleigh-Taylor instability in wire-array Z-pinch

    International Nuclear Information System (INIS)

    He Kaihui; Feng Kaiming; Li Qiang; Gao Chunming

    2000-01-01

    It is important to research into the MHD Rayleigh-Taylor instability developed in Z-pinch implosion. A snowplough model of the single wire Z-pinch is presented. The perturbation amplitude of Rayleigh-Taylor instability in the wire-array Z-pinch is analyzed quantitatively. Sheared axial flow is put forward to mitigate and reduce the Rayleigh-Taylor instability. And other approaches used to mitigate MHD instability in such a super-fast process are explored

  1. An endogenous Taylor condition in an endogenous growth monetary policy model

    OpenAIRE

    Le, Mai Vo; Gillman, Max; Minford, Patrick

    2007-01-01

    The paper derives a Taylor condition as part of the agent's equilibrium behavior in an endogenous growth monetary economy. It shows the assumptions necessary to make it almost identical to the original Taylor rule, and that it can interchangably take a money supply growth rate form. From the money supply form, simple policy experiments are conducted. A full central bank policy model is derived that includes the Taylor condition along with equations comparable to the standard aggregate-demand/...

  2. Non-vanishing of Taylor coefficients and Poincaré series

    DEFF Research Database (Denmark)

    O'Sullivan, C.; Risager, Morten S.

    2013-01-01

    We prove recursive formulas for the Taylor coefficients of cusp forms, such as Ramanujan's Delta function, at points in the upper half-plane. This allows us to show the non-vanishing of all Taylor coefficients of Delta at CM points of small discriminant as well as the non-vanishing of certain...... Poincaré series. At a "generic" point, all Taylor coefficients are shown to be non-zero. Some conjectures on the Taylor coefficients of Delta at CM points are stated....

  3. The right versus the good? On the right in the Philosophy of Charles Taylor

    Directory of Open Access Journals (Sweden)

    Javier García Caladín

    2013-05-01

    Full Text Available The aim of this article is to analyze the famous confrontation between the right and the good. We start with the analysis of Charles Taylor about the different significances of the good and his criticism to a procedural and restrictive approach of the moral (such as Habermas and Kymlicka. Secondly, we review in depth the ethics of Taylor and we stress the vague remark of «the just» in the use of Taylor. Finally, we evaluate the deontological deficiencies of the ethics of Taylor and try to find other ways to complement it.

  4. High Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

    Science.gov (United States)

    Scott, James R.; Martini, Michael C.

    2008-01-01

    Taylor series integration is implemented in a spacecraft trajectory analysis code-the Spacecraft N-body Analysis Program (SNAP) - and compared with the code s existing eighth-order Runge-Kutta Fehlberg time integration scheme. Nine trajectory problems, including near Earth, lunar, Mars and Europa missions, are analyzed. Head-to-head comparison at five different error tolerances shows that, on average, Taylor series is faster than Runge-Kutta Fehlberg by a factor of 15.8. Results further show that Taylor series has superior convergence properties. Taylor series integration proves that it can provide rapid, highly accurate solutions to spacecraft trajectory problems.

  5. Highly Symmetric and Congruently Tiled Meshes for Shells and Domes

    Science.gov (United States)

    Rasheed, Muhibur; Bajaj, Chandrajit

    2016-01-01

    We describe the generation of all possible shell and dome shapes that can be uniquely meshed (tiled) using a single type of mesh face (tile), and following a single meshing (tiling) rule that governs the mesh (tile) arrangement with maximal vertex, edge and face symmetries. Such tiling arrangements or congruently tiled meshed shapes, are frequently found in chemical forms (fullerenes or Bucky balls, crystals, quasi-crystals, virus nano shells or capsids), and synthetic shapes (cages, sports domes, modern architectural facades). Congruently tiled meshes are both aesthetic and complete, as they support maximal mesh symmetries with minimal complexity and possess simple generation rules. Here, we generate congruent tilings and meshed shape layouts that satisfy these optimality conditions. Further, the congruent meshes are uniquely mappable to an almost regular 3D polyhedron (or its dual polyhedron) and which exhibits face-transitive (and edge-transitive) congruency with at most two types of vertices (each type transitive to the other). The family of all such congruently meshed polyhedra create a new class of meshed shapes, beyond the well-studied regular, semi-regular and quasi-regular classes, and their duals (platonic, Catalan and Johnson). While our new mesh class is infinite, we prove that there exists a unique mesh parametrization, where each member of the class can be represented by two integer lattice variables, and moreover efficiently constructable. PMID:27563368

  6. Dome shaped micro-laser encapsulated in a flexible film

    Science.gov (United States)

    Ioppolo, T.; Manzo, M.

    2014-11-01

    In this paper, we demonstrated multimode laser emission from a dome shaped micro-scale resonator encapsulated in a flexible polymer film. The resonator with a radius of ~60 microns was made of Norland Blocking Adhesive (NBA 107) doped with a solution of rhodamine 6G and ethanol. The dome was encapsulated in a flexible polymeric film made of polydymethylsiloxane (PDMS) with a thickness of 1 mm. The micro-scale laser was optically pumped using a frequency doubled Q-switch Nd:YAG laser with pulse repetition of 10 Hz and pulse duration of 9 ns. Experiments were carried out to investigate the lasing properties of this laser structure. The pumping threshold for multimode laser emission was below 100 µJ cm-2. The average optical quality factor for all observed laser modes was of the order of 104. Using a fluence of 315.8 µJ cm-2 it was observed that the intensity of the laser emission dropped by 62% after 5 min of operation. These results showed that these solid state flexible lasers are easy to fabricate and can be integrated into novel flexible photonic devices and novel photonic sensors.

  7. Thermal responses in underground experiments in a dome salt formation

    International Nuclear Information System (INIS)

    Llewellyn, G.H.

    1977-01-01

    To provide design information for a radwaste repository in dome salt, in-situ experiments with nonradioactive heat sources are planned. Three such experiments using electrical heat sources are scheduled to be carried out in a salt dome. The purpose of these experiments is to acquire rock mechanics data to ascertain the structural deformation due to the thermal load imposed, to study brine migration and corrosion, and to provide thermal data. A data acquisition system is provided with these experiments to monitor temperatues, heat fluxes, stresses, and ground displacement. A thermal analysis was made on models of each of these experiments. The objective of the analysis is to verify the capability of making accurate transient temperature predictions by the use of computer modeling techniques. Another purpose is to measure in-situ thermal conductivity and compare the results with measurements taken from core samples. The HEATING5 computer program was used to predict transient temperatures around the experiments for periods up to 2 years using two-dimensional and three-dimensional heat transfer models. The results of analysis are presented with the associated boundary conditions used in the individual models

  8. Sealing considerations for repository shafts in bedded and dome salt

    International Nuclear Information System (INIS)

    1981-12-01

    The report reviews the geologic and hydrologic data base for penetration seal designs referenced to the Los Medanos bedded salt site in New Mexico and to four candidate salt domes in the Gulf Interior. Experience with existing shafts highlights the importance, for shaft decommissioning as well as operation, of achieving an adequate seal at and immediately below the top of salt. Possible construction procedures for repository shafts are reviewed, noting advantages and disadvantages with respect to repository sealing. At this stage, there does not appear to be a clear preference for excavation by drill and blast or by drilling. If conventional drill and blast methods are used, it may be necessary to grout in permeable zones above the salt. An important consideration with respect to sealing is that grouting operations (or freezing should it be used) should not establish connections between the top of salt and water-bearing zones higher in the stratigraphic section. Generally, it is concluded that Los Medanos and the dome salt sites are favorable candidate repository sites from the point of view of sealing

  9. The Dome C site testing from an atmospheric physicist view

    Science.gov (United States)

    Argentini, S.; Pietroni, I.

    Atmospheric field experiments were made at the French-Italian station of Concordia at Dome C during several years. These experiments were limited to the summer season. In 2005 Concordia has become a permanent base, this allowed to carry out STABLEDC (STudy of the Atmospheric Boundary Layer Environmental at Dome C plateau station) that is an atmospheric field experiment of the duration of one year. The aim of STABLEDC was to study the processes occurring in the long-lived stable and the weak convective atmospheric boundary layers, observed during winter and summer, respectively, and to collect the relevant parameters for the atmospheric models. Both in situ and ground based remote sensing instruments have been used to monitor the meteorological parameters. The first part of the paper gives a brief illustration of the objectives of the field experiment, and a description of site and instrumentation. The second part shows the behaviour of some micrometeorological parameters: temperature, wind speed, sensible heat flux. The surface radiation balance components are also shown. Finally some experimental activities are proposed.

  10. Nonlinear vibration of a hemispherical dome under external water pressure

    International Nuclear Information System (INIS)

    Ross, C T F; McLennan, A; Little, A P F

    2011-01-01

    The aim of this study was to analyse the behaviour of a hemi-spherical dome when vibrated under external water pressure, using the commercial computer package ANSYS 11.0. In order to achieve this aim, the dome was modelled and vibrated in air and then in water, before finally being vibrated under external water pressure. The results collected during each of the analyses were compared to the previous studies, and this demonstrated that ANSYS was a suitable program and produced accurate results for this type of analysis, together with excellent graphical displays. The analysis under external water pressure, clearly demonstrated that as external water pressure was increased, the resonant frequencies decreased and a type of dynamic buckling became likely; because the static buckling eigenmode was similar to the vibration eigenmode. ANSYS compared favourably with the in-house software, but had the advantage that it produced graphical displays. This also led to the identification of previously undetected meridional modes of vibration; which were not detected with the in-house software.

  11. Nonlinear vibration of a hemispherical dome under external water pressure

    Science.gov (United States)

    Ross, C. T. F.; McLennan, A.; Little, A. P. F.

    2011-07-01

    The aim of this study was to analyse the behaviour of a hemi-spherical dome when vibrated under external water pressure, using the commercial computer package ANSYS 11.0. In order to achieve this aim, the dome was modelled and vibrated in air and then in water, before finally being vibrated under external water pressure. The results collected during each of the analyses were compared to the previous studies, and this demonstrated that ANSYS was a suitable program and produced accurate results for this type of analysis, together with excellent graphical displays. The analysis under external water pressure, clearly demonstrated that as external water pressure was increased, the resonant frequencies decreased and a type of dynamic buckling became likely; because the static buckling eigenmode was similar to the vibration eigenmode. ANSYS compared favourably with the in-house software, but had the advantage that it produced graphical displays. This also led to the identification of previously undetected meridional modes of vibration; which were not detected with the in-house software.

  12. Structure-based membrane dome mechanism for Piezo mechanosensitivity.

    Science.gov (United States)

    Guo, Yusong R; MacKinnon, Roderick

    2017-12-12

    Mechanosensitive ion channels convert external mechanical stimuli into electrochemical signals for critical processes including touch sensation, balance, and cardiovascular regulation. The best understood mechanosensitive channel, MscL, opens a wide pore, which accounts for mechanosensitive gating due to in-plane area expansion. Eukaryotic Piezo channels have a narrow pore and therefore must capture mechanical forces to control gating in another way. We present a cryo-EM structure of mouse Piezo1 in a closed conformation at 3.7Å-resolution. The channel is a triskelion with arms consisting of repeated arrays of 4-TM structural units surrounding a pore. Its shape deforms the membrane locally into a dome. We present a hypothesis in which the membrane deformation changes upon channel opening. Quantitatively, membrane tension will alter gating energetics in proportion to the change in projected area under the dome. This mechanism can account for highly sensitive mechanical gating in the setting of a narrow, cation-selective pore. © 2017, Guo et al.

  13. Dome shaped micro-laser encapsulated in a flexible film

    International Nuclear Information System (INIS)

    Ioppolo, T; Manzo, M

    2014-01-01

    In this paper, we demonstrated multimode laser emission from a dome shaped micro-scale resonator encapsulated in a flexible polymer film. The resonator with a radius of ∼60 microns was made of Norland Blocking Adhesive (NBA 107) doped with a solution of rhodamine 6G and ethanol. The dome was encapsulated in a flexible polymeric film made of polydymethylsiloxane (PDMS) with a thickness of 1 mm. The micro-scale laser was optically pumped using a frequency doubled Q-switch Nd:YAG laser with pulse repetition of 10 Hz and pulse duration of 9 ns. Experiments were carried out to investigate the lasing properties of this laser structure. The pumping threshold for multimode laser emission was below 100 µJ cm −2 . The average optical quality factor for all observed laser modes was of the order of 10 4 . Using a fluence of 315.8 µJ cm −2 it was observed that the intensity of the laser emission dropped by 62% after 5 min of operation. These results showed that these solid state flexible lasers are easy to fabricate and can be integrated into novel flexible photonic devices and novel photonic sensors. (paper)

  14. Seismic measurements of explosions in the Tatum Salt Dome, Mississippi

    Science.gov (United States)

    Borcherdt, Roger D.; Healy, J.H.; Jackson, W.H.; Warren, D.R.

    1967-01-01

    Project Sterling provided for the detonation of a nuclear device in the cavity resulting from the Salmon nuclear explosion in the Tatum salt dome in southern Mississippi. It also provided for a high explosive (HE) comparison shot in a nearby drill hole. The purpose of the experiment was to gather information on the seismic decoupling of a nuclear explosion in a cavity by comparing seismic signals from a nuclear shot in the Salmon cavity with seismic signals recorded from Salmon and with seismic signals recorded from a muall (about 2 tons) HE shot in the salt dome. Surface seismic measurements were made by the U.S. Geological Survey, the U.S. Coast and Geodetic Survey, and the Air Force Technical Applications Center with coordination and overall direction by the Lawrence Radiation Laboratory. This report covers only the seismic measurements made by the U. S. Geological Survey. The first objective of this report is to describe the field recording procedures and the data obtained by the U. S. Geological Survey from these events. The second objective is to describe the spectral analyses which have been made on the data and the relative seismic amplitudes which have been determined from these analyses.

  15. Modelling the physical multiphase interactions of HNO3 between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

    Science.gov (United States)

    Chan, Hoi Ga; Frey, Markus M.; King, Martin D.

    2018-02-01

    Emissions of nitrogen oxide (NOx = NO + NO2) from the photolysis of nitrate (NO3-) in snow affect the oxidising capacity of the lower troposphere especially in remote regions of high latitudes with little pollution. Current air-snow exchange models are limited by poor understanding of processes and often require unphysical tuning parameters. Here, two multiphase models were developed from physically based parameterisations to describe the interaction of nitrate between the surface layer of the snowpack and the overlying atmosphere. The first model is similar to previous approaches and assumes that below a threshold temperature, To, the air-snow grain interface is pure ice and above To a disordered interface (DI) emerges covering the entire grain surface. The second model assumes that air-ice interactions dominate over all temperatures below melting of ice and that any liquid present above the eutectic temperature is concentrated in micropockets. The models are used to predict the nitrate in surface snow constrained by year-round observations of mixing ratios of nitric acid in air at a cold site on the Antarctic Plateau (Dome C; 75°06' S, 123°33' E; 3233 m a.s.l.) and at a relatively warm site on the Antarctic coast (Halley; 75°35' S, 26°39' E; 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34) but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that in winter air-snow interactions of nitrate are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain, similar to Bock et al. (2016). In summer, however, the air-snow exchange of nitrate is mainly driven by solvation into liquid micropockets following Henry's law with contributions to total surface snow NO3- concentrations of 75 and 80 % at Dome C and Halley

  16. Rayleigh-Taylor instability in multi-structured spherical targets

    International Nuclear Information System (INIS)

    Gupta, N.K.; Lawande, S.V.

    1986-01-01

    An eigenvalue equation for the exponential growth rate of the Rayleigh-Taylor instability is derived in spherical geometry. The free surface and jump boundary conditions are obtained from the eigenvalue equation. The eigenvalue equation is solved in the cases where the initial fluid density profile has a step function or exponential variation in space and analytical formulae for growth rate of the instability are obtained. The solutions for the step function are generalized for any number N of spherical zones forming an arbitrary fluid density profile. The results of the numerical calculations for N spherical zones are compared with the exact analytical results for exponential fluid density profile with N=10 and a good agreement is observed. The formalism is further used to study the effects of density gradients on Rayleigh-Taylor instability in spherical geometry. Also analytical formulae are presented for a particular case of N=3 and shell targets. The formalism developed here can be used to study the growth of the instability in present day multi-structured shell targets. (author)

  17. Rayleigh-Taylor mixing with time-dependent acceleration

    Science.gov (United States)

    Abarzhi, Snezhana

    2016-10-01

    We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a time-dependent acceleration. The acceleration is a power-law function of time, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical regimes of self-similar RT mixing-acceleration-driven Rayleigh-Taylor-type and dissipation-driven Richtymer-Meshkov-type with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with time-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

  18. Rayleigh-Taylor mixing with space-dependent acceleration

    Science.gov (United States)

    Abarzhi, Snezhana

    2016-11-01

    We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a space-dependent acceleration. The acceleration is a power-law function of space coordinate, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical sub-regimes of self-similar RT mixing - the acceleration-driven Rayleigh-Taylor-type mixing and dissipation-driven Richtymer-Meshkov-type mixing with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with space-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

  19. Inertial migration of particles in Taylor-Couette flows

    Science.gov (United States)

    Majji, Madhu V.; Morris, Jeffrey F.

    2018-03-01

    An experimental study of inertial migration of neutrally buoyant particles in the circular Couette flow (CCF), Taylor vortex flow (TVF) and wavy vortex flow (WVF) is reported. This work considers a concentric cylinder Taylor-Couette device with a stationary outer cylinder and rotating inner cylinder. The device has a radius ratio of η = ri/ro = 0.877, where ri and ro are the inner and outer radii of the flow annulus. The ratio of the annular width between the cylinders (δ = ro - ri) and the particle diameter (dp) is α = δ/dp = 20. For η = 0.877, the flow of a Newtonian fluid undergoes transitions from CCF to TVF and TVF to WVF at Reynolds numbers Re = 120 and 151, respectively, and for the dilute suspensions studied here, these critical Reynolds numbers are almost unchanged. In CCF, particles were observed to migrate, due to the competition between the shear gradient of the flow and the wall interactions, to an equilibrium location near the middle of the annulus with an offset toward the inner cylinder. In TVF, the vortex motion causes the particles to be exposed to the shear gradient and wall interactions in a different manner, resulting in a circular equilibrium region in each vortex. The radius of this circular region grows with increase in Re. In WVF, the azimuthal waviness results in fairly well-distributed particles across the annulus.

  20. Nonlinear interaction of Rayleigh--Taylor and shear instabilities

    International Nuclear Information System (INIS)

    Finn, J.M.

    1993-01-01

    Results on the nonlinear behavior of the Rayleigh--Taylor instability and consequent development of shear flow by the shear instability [Phys. Fluids B 4, 488 (1992)] are presented. It is found that the shear flow is generated at sufficient amplitude to reduce greatly the convective transport. For high viscosity, the time-asymptotic state consists of an equilibrium with shear flow and vortex flow (with islands, or ''cat's eyes''), or a relaxation oscillation involving an interplay between the shear instability and the Rayleigh--Taylor instability in the presence of shear. For low viscosity, the dominant feature is a high-frequency nonlinear standing wave consisting of convective vortices localized near the top and bottom boundaries. The localization of these vortices is due to the smaller shear near the boundary regions. The convective transport is largest around these convective vortices near the boundary and there is a region of good confinement near the center. The possible relevance of this behavior to the H mode and edge-localized modes (ELM's) in the tokamak edge region is discussed

  1. Stochastic ice stream dynamics.

    Science.gov (United States)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-09

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  2. Sea Ice Ecosystems

    Science.gov (United States)

    Arrigo, Kevin R.

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters.

  3. Ross Ice Shelf, Antarctic Ice and Clouds

    Science.gov (United States)

    1991-01-01

    In this view of Antarctic ice and clouds, (56.5S, 152.0W), the Ross Ice Shelf of Antarctica is almost totally clear, showing stress cracks in the ice surface caused by wind and tidal drift. Clouds on the eastern edge of the picture are associated with an Antarctic cyclone. Winds stirred up these storms have been known to reach hurricane force.

  4. Transparent Inflatable Column Film Dome for Nuclear Stations, Stadiums, and Cities

    Directory of Open Access Journals (Sweden)

    Alexander Bolonkin

    2011-01-01

    Full Text Available In a series of previous articles, one of the authors published designs of the AB Dome which can cover a city, important large installations or subregions by a transparent thin film supported by a small additional air overpressure. The AB Dome keeps the outside atmospheric conditions from the interior protecting a city from chemical, bacterial, and radioactive weapons (wastes. The design in this article differs from previous one as this design employs an inflatable columns which does not need an additional pressure (overpressure inside the dome and is cheaper in construction (no powered air pumping station and in operation (no special entrance airlock and permanent pumping expense. When dome is supported by columns, no overpressure is required inside the dome which is important when the dome covers a damaged nuclear reactor. The nuclear reactor may produce radioactive gases and dust, and, as inflatable domes are not typically hermetically sealed, the increased pressure inside the dome can leak out gas and dust into the atmosphere. The suggested design does not have this drawback. Positive pressure gradients expel dust particles—neutral pressure gradients will not. (Negative pressure gradients may even be possible in certain configurations.

  5. Bilateral Dome-Shaped Macula with Serous Macular Detachment in a Child

    OpenAIRE

    Cebeci, Zafer; Kir, Nur

    2015-01-01

    Dome-shaped macula is a structural disorder and optical coherence tomography (OCT) helps us to confirm macular convexity. We describe the first case of bilateral dome-shaped macula in an 8-year-old boy with subretinal fluid. The patient was diagnosed using spectral-domain OCT and received indocyanine green angiography-guided half-fluence photodynamic therapy as treatment.

  6. The mythic structure in the black dome of the Haftpeikar: Study of Hero's journey in the first dome

    Directory of Open Access Journals (Sweden)

    Seyed Kazem Mousavi

    2016-12-01

    Full Text Available Abstract In this paper the Vogler Hero's journey is used for analyzing the mythic structures and hero's journey of the first dome of the Haftpeikar. Vogler Released his founds in the Writer's Journey book. This book that is really dependent on Campbell's Single Myth Theory is a practical guidance for script writing and review of that. The levels of the hero's journey in his book are include: The normal world, invitation to the story, reject the invitation, visit the mentor, passing the first gate, the exams, the allies, the enemies, qualifying to the deepest cave, trial, the reward, the road back, resurrection, return with the elixir.  In this paper, at first the properties of each level of the hero's journey theory are matching with the journey's levels in the black dome story. After that seven useful archetypes including hero, mentor, threshold guardian, herald, shape shifter, the shadow and trickster, are determined in the text.  Black dome has several journeys' cycles. Journey's that are seen in this dome are: (Bahram's journey: A part of the internal journey of Bahram in black dome. (The king's maid journey: Internal journey of the king's maid that wears black clothes after hearing the story. (King of black clothes' journey: The king's journey to the Madhooshan city for exploring the mystery of the black alien. (The reader's journey: This internal journey belongs to the readers of the first dome that learn their lessons through traveling to the character's world. (Nezami's journey: The Nezami's internal journey with composing the text. Checking the reader's journey and black dome's composer is out of this text. While the first and second journey just saying some parts, the black king has completer levels and for affecting on the other journeys is the most important story of the first dome. Therefore at first we check the black king story and we explain the other journeys.  The goal of this paper in addition to the usage of the vogler

  7. Stochastic modelling of basal temperatures in divide regions of the Antarctic ice sheet over the last 1.5 million years

    Science.gov (United States)

    Van Liefferinge, Brice; Pattyn, Frank; Cavitte, Marie G. P.; Young, Duncan A.; Roberts, Jason L.

    2017-04-01

    The quest for oldest ice in Antarctica has recently been launched through an EU H2020 project (Beyond EPICA - Oldest Ice) and aims at identifying suitable areas for a potential future drilling. Retrieving an ice core of such age is essential to understand the relation between orbital changes and atmospheric composition during the mid-Pliocene transition. However, sites for a potential undisturbed record of 1.5 million-year old ice in Antarctica are difficult to find and require slow-moving ice (preferably an ice divide) and basal conditions that are not disturbed by large topographic variations. Furthermore, ice should be sufficiently thick but cold basal conditions should still prevail, since basal melting would destroy the bottom layers. Therefore, ice-flow conditions and thermodynamic characteristics are crucial for identifying potential locations of undisturbed ice. Van Liefferinge and Pattyn (2013) identified suitable areas based on a pan-Antarctic simplified thermodynamic ice sheet model and demonstrated that uncertainty in geothermal conditions remain a major unknown. In order to refine these estimates, and provide uncertainties, we employ a full thermo-mechanically coupled higher-order ice sheet model (Pattyn, 2003; Pattyn et al., 2004). Initial conditions for the calculations are based on an inversion of basal slipperiness, based on observed surface topography (Pollard and DeConto, 2012; Pattyn, in prep.). Uncertainties in geothermal conditions are introduced using the convolution of two Gaussian probability density functions: (a) the reconstruction of the Antarctic ice sheet geometry and testing ice thickness variability over the last 2 million years (Pollard and DeConto, 2009) and (b) the surface temperature reconstruction over the same period (Snyder et al., 2016). The standard deviation, the skewness and the kurtosis of the whole Antarctic ice sheet are analyzed to observe likely probable melt conditions. Finally, we focus on model results in the

  8. A study of the decontamination procedures used for chemical analysis of polar deep ice cores

    Directory of Open Access Journals (Sweden)

    Takayuki Miyake

    2009-11-01

    Full Text Available We investigated the decontamination procedures used on polar deep ice cores before chemical analyses such as measurements of the concentrations of iron species and dust (microparticles. We optimized cutting and melting protocols for decontamination using chemically ultraclean polyethylene bags and simulated ice samples made from ultrapure water. For dust and ion species including acetate, which represented a high level of contamination, we were able to decrease contamination to below several μg l^ for ion concentrations and below 10000 particles ml^ for the dust concentration. These concentration levels of ion species and dust are assumed to be present in the Dome Fuji ice core during interglacial periods. Decontamination of the ice core was achieved by cutting away approximately 3 mm of the outside of a sample and by melting away approximately 30% of a sample's weight. Furthermore, we also report the preparation protocols for chemical analyses of the 2nd Dome Fuji ice core, including measurements of ion and dust concentrations, pH, electric conductivity (EC, and stable isotope ratios of water (δD and δO, based on the results of the investigation of the decontamination procedures.

  9. Effect of Pyramidal Dome Geometry on the Acoustical Characteristics in A Mosque

    Directory of Open Access Journals (Sweden)

    Dg. H. Kassim

    2014-12-01

    Full Text Available As an important symbol in Islam, a mosque is built with architectural grandeur. Among the characteristics is its high ceiling and it is usually constructed with a typical spherical dome shape. Some mosques, however, are influenced by the local culture and the dome can be of a different shape, such as pyramidal, as found in mosques in Malacca, Malaysia. This paper presents an assessment of the internal acoustical characteristics of a mosque having a pyramidal dome. The study is conducted by means of computer simulation using CATT indoor acoustic software. Reverberation time and clarity are taken to evaluate the intelligibility of speech. The effect of the angle and height of the dome on the acoustical parameters is discussed. It is found that a pyramidal dome with a steeper angle contributes to poor acoustic clarity.

  10. Sensitivity of storage field performance to geologic and cavern design parameters in salt domes.

    Energy Technology Data Exchange (ETDEWEB)

    Ehgartner, Brian L. (Sandia National Laboratories, Albuquerque, NM); Park, Byoung Yoon

    2009-03-01

    A sensitivity study was performed utilizing a three dimensional finite element model to assess allowable cavern field sizes for strategic petroleum reserve salt domes. A potential exists for tensile fracturing and dilatancy damage to salt that can compromise the integrity of a cavern field in situations where high extraction ratios exist. The effects of salt creep rate, depth of salt dome top, dome size, caprock thickness, elastic moduli of caprock and surrounding rock, lateral stress ratio of surrounding rock, cavern size, depth of cavern, and number of caverns are examined numerically. As a result, a correlation table between the parameters and the impact on the performance of storage field was established. In general, slower salt creep rates, deeper depth of salt dome top, larger elastic moduli of caprock and surrounding rock, and a smaller radius of cavern are better for structural performance of the salt dome.

  11. Direct north-south synchronization of abrupt climate change record in ice cores using Beryllium 10

    Directory of Open Access Journals (Sweden)

    G. M. Raisbeck

    2007-09-01

    Full Text Available A new, decadally resolved record of the 10Be peak at 41 kyr from the EPICA Dome C ice core (Antarctica is used to match it with the same peak in the GRIP ice core (Greenland. This permits a direct synchronisation of the climatic variations around this time period, independent of uncertainties related to the ice age-gas age difference in ice cores. Dansgaard-Oeschger event 10 is in the period of best synchronisation and is found to be coeval with an Antarctic temperature maximum. Simulations using a thermal bipolar seesaw model agree reasonably well with the observed relative climate chronology in these two cores. They also reproduce three Antarctic warming events observed between A1 and A2.

  12. A natural ice boom

    Energy Technology Data Exchange (ETDEWEB)

    Hopper, H.R. [Manitoba Hydro, Winnipeg, MB (Canada)

    1998-10-01

    Planning for ice jams and ice movements are critical on the Nelson River in northern Manitoba in designing cofferdams. Experience on the St. Lawrence River demonstrated the possibility of exercising some control over ice action by judicious placement of log booms or ice control structures. The success of experiments with man-made controls led to field tests in which an ice sheet of sufficient magnitude and competence was introduced into the open water stream of the Nelson River. The ice sheet was subsequently jammed in a narrow channel, thereby creating a natural ice bridge or boom upstream of a proposed hydro development. Under favourable conditions, this boom would initiate the progression of the ice cover from its location upstream, cutting off the downstream reach from the ice producing potential of the upstream reach. Although ice would still be generated downstream, the length of the reach between the ice boom and the development site would be short enough that ice jamming at the development site would never occur. Although problems in blasting prevented the introduction of a competent ice sheet into the main stream of the river at the location chosen, sufficient confidence in the theory was gained to warrant further consideration. 4 refs., 1 tab., 10 figs.

  13. Expressing the remainder of the Taylor polynomial when the function lacks smoothness

    Czech Academy of Sciences Publication Activity Database

    Hošek, Radim

    2017-01-01

    Roč. 72, č. 3 (2017), s. 126-130 ISSN 0013-6018 Institutional support: RVO:67985840 Keywords : Taylor polynomial * Taylor theorem Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics http://www.ems-ph.org/doi/10.4171/EM/335

  14. Taylor-Made Education: The Influence of the Efficiency Movement on the Testing of Reading Skills.

    Science.gov (United States)

    Allen, JoBeth

    Much of what has developed in the testing of reading harkens back to the days of the "Cult of Efficiency" movement in education that can be largely attributed to Frederick Winslow Taylor. Taylor spent most of his productive years studying time and motion in an attempt to streamline industrial production so that people could work as…

  15. Shapes of an Air Taylor Bubble in Stagnant Liquids Influenced by Different Surface Tensions

    Science.gov (United States)

    Lertnuwat, B.

    2018-02-01

    The aim of this work is to propose an empirical model for predicting shapes of a Taylor bubble, which is a part of slug flows, under different values of the surface tension in stagnant liquids by employing numerical simulations. The k - Ɛ turbulence model was used in the framework of finite volume method for simulating flow fields in a unit of slug flow and also the pressure distribution on a Taylor bubble surface. Assuming that an air pressure distribution inside the Taylor bubble must be uniform, a grid search method was exploited to find an appropriate shape of a Taylor bubble for six values of surface tension. It was found that the shape of a Taylor bubble would be blunter if the surface tension was increased. This was because the surface tension affected the Froude number, controlling the flow around a Taylor bubble. The simulation results were also compared with the Taylor bubble shape, created by the Dumitrescu-and-Taylor model and former studies in order to ensure that they were consistent. Finally, the empirical model was presented from the simulation results.

  16. Disentangling the origins of torque enhancement through wall roughness in Taylor-Couette turbulence

    NARCIS (Netherlands)

    Zhu, Xiaojue; Verzicco, Roberto; Lohse, Detlef

    2017-01-01

    Direct numerical simulations (DNS) are performed to analyse the global transport properties of turbulent Taylor-Couette flow with inner rough wall up to Taylor number Ta = 1010. The dimensionless torque Nuω shows an effective scaling of Nuω ∝ Ta0.42±0.01, which is steeper than the ultimate regime

  17. An Attempt to Extend Taylor-Spence Drive Theory to Vocational Choice Behavior

    Science.gov (United States)

    Sharf, Richard S.

    1972-01-01

    Predictions were made from Taylor-Spence drive theory about vocational choice behavior. Although the results did not specifically support the predictions made from Taylor-Spence theory, they indicated the potential usefulness of certain concepts in this theory and suggested several lines of inquiry for further research. (Author)

  18. An Application of Taylor Models to the Nakao Method on ODEs

    OpenAIRE

    Yamamoto, Nobito; Komori, Takashi

    2009-01-01

    The authors give short survey on validated computaion of initial value problems for ODEs especially Taylor model methods. Then they propose an application of Taylor models to the Nakao method which has been developed for numerical verification methods on PDEs and apply it to initial value problems for ODEs with some numerical experiments.

  19. Further design work on a repository in a salt dome

    International Nuclear Information System (INIS)

    Hamstra, J.; Janssen, L.G.L.

    1985-01-01

    The report presents the cost estimate and the work plan for the construction of a repository, to be mined in a medium-size salt dome for the simultaneous disposal of different categories of solid radioactive wastes. The repository is designed for all categories of waste from 40 years of operation of 25 nuclear power stations of 1000 MWe each, including the decommissioning waste from these stations as well as all the radioactive wastes from the hospitals and laboratories during a hundred-year period. The cost estimate includes preparation of a site, the construction, operation and abandonment of that repository. Moreover, an outline has been presented for a future updating and optimization study of the concept

  20. Exploratory shaft facility preliminary designs - Gulf Interior Region salt domes

    International Nuclear Information System (INIS)

    1983-09-01

    The purpose of the Preliminary Design Report, Gulf Interior Region, is to provide a description of the preliminary design for an Exploratory Shaft Facility on the Richton Dome, Mississippi. This issue of the report describes the preliminary design for constructing the exploratory shaft using the Large Hole Drilling method of construction and outlines the preliminary design and estimates of probable construction cost. The Preliminary Design Report is prepared to complement and summarize other documents that comprise the design at the preliminary stage of completion, December 1982. Other design documents include drawings, cost estimates and schedules. The preliminary design drawing package, which includes the construction schedule drawing, depicts the descriptions in this report. For reference, a list of the drawing titles and corresponding numbers are included in the Appendix. The report is divided into three principal sections: Design Basis, Facility Description and Construction Cost Estimate

  1. The early quaternary sediments above the Gorleben salt dome

    International Nuclear Information System (INIS)

    Mueller, H.

    1986-01-01

    About 1500 borehole samples from the 90 m thick pre-Elsterian Pleistocene sediments above the Gorleben salt dome were studied to establish the palynostratigraphy of the main part of the still poorly known 'Cromerian Complex'. With the exception of two isolated sink holes above the gypsum cap rock, which developed during the early Bavelian, the investigated pre-Elsterian Pleistocene sediments were deposited in a very shallow lake, similar to the present-day Steinhuder Meer (NW Germany). Therefore, subrosion (subsurface erosion of salt) and sedimentation kept pace with each other during this time interval. Small discordances - similar to those in the Holocene sediments of the Steinhuder Meer - are frequent, but do not hamper the close correlation (to within 1 cm) between the different boreholes. (orig.) [de

  2. The early quaternary sediments above the Gorleben salt dome

    International Nuclear Information System (INIS)

    Mueller, H.

    1986-01-01

    About 1500 borehole samples from the 90 m thick pre-Elsterian Pleistocene sediments above the Gorleben salt dome were studied to establish the palynostratigraphy of the main part of the still poorly known 'Cromerian Complex'. With the exception of two isolated sink holes above the gypsum cap rock, which developed during the early Bavelian, the investigated pre-Elsterian Pleistocene sediments were deposited in a very shallow lake, similar to the present-day Steinhuder Meer (NW Germany). Therefore, subrosion (subsurface erosion of salt) and sedimentation kept pace with each other during this time interval. Small discordances - similar to those in the Holocene sediments of the Steinhuder Meer - are frequent, but do not hamper the close correlation (to within 1 cm) between the different boreholes. (orig./PW) [de

  3. Forecast Icing Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Forecast Icing Product (FIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The FIP algorithm uses...

  4. Current Icing Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Current Icing Product (CIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The CIP algorithm combines...

  5. Sputtering of water ice

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Vidal, R.A.; Svendsen, W.; Schou, J.; Shi, M.; Bahr, D.A.; Atteberrry, C.L.

    2003-01-01

    We present results of a range of experiments of sputtering of water ice together with a guide to the literature. We studied how sputtering depends on the projectile energy and fluence, ice growth temperature, irradiation temperature and external electric fields. We observed luminescence from the decay of H(2p) atoms sputtered by heavy ion impact, but not bulk ice luminescence. Radiolyzed ice does not sputter under 3.7 eV laser irradiation

  6. Impact of climate fluctuations on deposition of DDT and hexachlorocyclohexane in mountain glaciers: Evidence from ice core records

    International Nuclear Information System (INIS)

    Wang Xiaoping; Gong Ping; Zhang, Qianggong; Yao Tandong

    2010-01-01

    How do climate fluctuations affect DDT and hexachlorocyclohexane (HCH) distribution in the global scale? In this study, the interactions between climate variations and depositions of DDT and HCH in ice cores from Mt. Everest (the Tibetan Plateau), Mt. Muztagata (the eastern Pamirs) and the Rocky Mountains were investigated. All data regarding DDT/HCH deposition were obtained from the published results. Concentrations of DDT and HCH in an ice core from Mt. Everest were associated with the El Nino-Southern Oscillation. Concentrations of DDT in an ice core from Mt. Muztagata were significantly correlated with the Siberia High pattern. Concentrations of HCH in an ice core from Snow Dome of the Rocky Mountains responded to the North Atlantic Oscillation. These associations suggested that there are some linkages between climate variations and the global distribution of persistent organic pollutants. - Our study approves the potential contribution of ice core records of POPs to transport mechanisms of POPs.

  7. Earth's core formation due to the Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Ida, S.; Nakagawa, Y.; Nakazawa, K.

    1987-01-01

    A protoearth accretion stage configuration consisting of an undifferentiated solid core, an intermediate metal-melt layer, and an outer silicate-melt layer, is presently taken as the initial state in an investigation of Rayleigh-Taylor instability-induced core formation. The Ida et al. (to be published) quantitative results on the instability in a self-gravitating fluid sphere are used. The instability is found to occur through the translational mode on a time-scale of about 10 hr, in the case where the metal-melt layer is greater than about 1 km; this implies that the earth's core formed due to the undifferentiated solid core's translation upon the outer layer's melting. Differentiation would then have occurred in the late accretion stage. 17 references

  8. Pade approximants for entire functions with regularly decreasing Taylor coefficients

    International Nuclear Information System (INIS)

    Rusak, V N; Starovoitov, A P

    2002-01-01

    For a class of entire functions the asymptotic behaviour of the Hadamard determinants D n,m as 0≤m≤m(n)→∞ and n→∞ is described. This enables one to study the behaviour of parabolic sequences from Pade and Chebyshev tables for many individual entire functions. The central result of the paper is as follows: for some sequences {(n,m(n))} in certain classes of entire functions (with regular Taylor coefficients) the Pade approximants {π n,m(n) }, which provide the locally best possible rational approximations, converge to the given function uniformly on the compact set D={z:|z|≤1} with asymptotically best rate

  9. Mode coupling in nonlinear Rayleigh--Taylor instability

    International Nuclear Information System (INIS)

    Ofer, D.; Shvarts, D.; Zinamon, Z.; Orszag, S.A.

    1992-01-01

    This paper studies the interaction of a small number of modes in the two-fluid Rayleigh--Taylor instability at relatively late stages of development, i.e., the nonlinear regime, using a two-dimensional hydrodynamic code incorporating a front-tracking scheme. It is found that the interaction of modes can greatly affect the amount of mixing and may even reduce the width of the mixing region. This interaction is both relatively long range in wave-number space and also acts in both directions, i.e., short wavelengths affect long wavelengths and vice versa. Three distinct stages of interaction have been identified, including substantial interaction among modes some of which may still be in their classical (single mode) ''linear'' phase

  10. Rayleigh-Taylor analysis in a laser-induced plasma

    International Nuclear Information System (INIS)

    Marin, R A; Gonzales, C A; Riascos, H

    2012-01-01

    We report the conditions (plasma parameters) under which the Rayleigh-Taylor Instability (RTI) develops in an Al plasma produced by a Nd:Yag pulsed laser with a fluence range of 1 to 4 J/cm 2 , wavelength of 1064nm and 10Hz repetition rate. The used data correspond to different pressure values of the ambient N atmosphere. From previous works, we took the RTI growth rate form. From the perturbation theory the instability amplitude is proportional to e -ηt . Using the drag model, we calculated the plume dynamics equations integrating the instability term and plotted the instability growth profile with the delay time values to get critical numbers for it, in order to show under which conditions the RTI appears.

  11. Simulation of Rayleigh--Taylor flows using vortex blobs

    International Nuclear Information System (INIS)

    Kerr, R.M.

    1988-01-01

    An inviscid boundary-integral method is modified in order to study the single-scale Rayleigh--Taylor instability for arbitrary Atwood number. The primary modification uses vortex blobs to smooth the Green's function and suppress a finite time singularity in the curvature. Additional modifications to earlier codes such as using second-order central differences along the interface to accommodate spikes in the vorticity and spreading the nodes evenly along the interface to suppress clustering of nodes are designed to maintain resolution and accuracy. To achieve second-order accuracy in time when the nodes are spread, an extra predictor step is needed that shifts the nodes before the variables are advanced. The method successfully follows the development of a single mode to states with asymptotic velocities for the bubble and spike that depend on the Atwood number and are independent of the blob size. Incipient droplet formation is observed. copyright 1988 Academic Press, Inc

  12. Lattice QCD at finite temperature and density from Taylor expansion

    Science.gov (United States)

    Steinbrecher, Patrick

    2017-01-01

    In the first part, I present an overview of recent Lattice QCD simulations at finite temperature and density. In particular, we discuss fluctuations of conserved charges: baryon number, electric charge and strangeness. These can be obtained from Taylor expanding the QCD pressure as a function of corresponding chemical potentials. Our simulations were performed using quark masses corresponding to physical pion mass of about 140 MeV and allow a direct comparison to experimental data from ultra-relativistic heavy ion beams at hadron colliders such as the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN. In the second part, we discuss computational challenges for current and future exascale Lattice simulations with a focus on new silicon developments from Intel and NVIDIA.

  13. Size invariance of the granular Rayleigh-Taylor instability.

    Science.gov (United States)

    Vinningland, Jan Ludvig; Johnsen, Øistein; Flekkøy, Eirik G; Toussaint, Renaud; Måløy, Knut Jørgen

    2010-04-01

    The size scaling behavior of the granular Rayleigh-Taylor instability [J. L. Vinningland, Phys. Rev. Lett. 99, 048001 (2007)] is investigated experimentally, numerically, and theoretically. An upper layer of grains displaces a lower gap of air by organizing into dense fingers of falling grains separated by rising bubbles of air. The dependence of these structures on the system and grain sizes is investigated. A spatial measurement of the finger structures is obtained by the Fourier power spectrum of the wave number k. As the size of the grains increases the wave number decreases accordingly which leaves the dimensionless product of wave number and grain diameter, dk, invariant. A theoretical interpretation of the invariance, based on the scaling properties of the model equations, suggests a gradual breakdown of the invariance for grains smaller than approximately 70 microm or greater than approximately 570 microm in diameter.

  14. Saffman-Taylor Instability for a non-Newtonian fluid

    Science.gov (United States)

    Daripa, Prabir

    2013-11-01

    Motivated by applications, we study classical Saffman-Taylor instability involving displacement of an Oldroyd-B fluid displaced by air in a Hele-Shaw cell. The lubrication approximation is used by neglecting the vertical component of the velocity. We obtain an explicit expression of one of the components of the extra-stress perturbations tensor in terms of the horizontal velocity perturbations. The main result is an explicit formula for the growth constant (in time) of perturbations, given by a ratio in which a term depending on the relaxation and retardation (time) constants appears in the denominator of the ratio. This exact result compares extremely well with known numerical results. It is found that flow is more unstable than the corresponding Newtonian case. This is a joint work with Gelu Pasa. The research has been made possible by an NPRP Grant # 08-777-1-141 from the Qatar National Research Fund (a member of the Qatar Foundation).

  15. Numerical Simulation of Anisotropic Preheating Ablative Rayleigh–Taylor Instability

    International Nuclear Information System (INIS)

    Li-Feng, Wang; Wen-Hua, Ye; Ying-Jun, Li

    2010-01-01

    The linear growth rate of the anisotropic preheating ablative Rayleigh–Taylor instability (ARTI) is studied by numerical simulations. The preheating model κ(T) = κ SH [1 + f(T)] is applied, where f(T) is the preheating function interpreting the preheating tongue effect in the cold plasma ahead of the ablative front. An arbitrary coefficient D is introduced in the energy equation to study the influence of transverse thermal conductivity on the growth of the ARTI. We find that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. Numerical simulations exhibit a significant stabilization of the ablation front by improving the transverse thermal conduction. Our results are in general agreement with the theory analysis and numerical simulations by Masse [Phys. Rev. Lett. 98 (2007) 245001]. (physics of gases, plasmas, and electric discharges)

  16. Numerical simulation of anisotropic preheating ablative Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Wang Lifeng; Ye Wenhua; Li Yingjun

    2010-01-01

    The linear growth rate of the anisotropic preheating ablative Rayleigh-Taylor instability (ARTI) is studied by numerical simulations. The preheating model κ(T)=κ SH [1+f(T)] is applied, where f(T) is the preheating function interpreting the preheating tongue effect in the cold plasma ahead of the ablative front. An arbitrary coefficient D is introduced in the energy equation to study the influence of transverse thermal conductivity on the growth of the ARTI. We find that enhancing diffusion in a plane transverse to the mean longitudinal flow can strongly reduce the growth of the instability. Numerical simulations exhibit a significant stabilization of the ablation front by improving the transverse thermal conduction. Our results are in general agreement with the theory analysis and numerical simulations by Masse. (authors)

  17. Taylor-Lagrange regularization scheme and light-front dynamics

    International Nuclear Information System (INIS)

    Grange, P.; Mathiot, J.-F.; Mutet, B.; Werner, E.

    2010-01-01

    The recently proposed renormalization scheme based on the definition of field operators as operator valued distributions acting on specific test functions is shown to be very convenient in explicit calculations of physical observables within the framework of light-front dynamics. We first recall the main properties of this procedure based on identities relating the test functions to their Taylor remainder of any order expressed in terms of Lagrange's formulae, hence the name given to this scheme. We thus show how it naturally applies to the calculation of state vectors of physical systems in the covariant formulation of light-front dynamics. As an example, we consider the case of the Yukawa model in the simple two-body Fock state truncation.

  18. Observation of Rayleigh - Taylor growth to short wavelengths on Nike

    International Nuclear Information System (INIS)

    Pawley, C.J.; Bodner, S.E.; Dahlburg, J.P.; Obenschain, S.P.; Schmitt, A.J.; Sethian, J.D.; Sullivan, C.A.; Gardner, J.H.; Aglitskiy, Y.; Chan, Y.; Lehecka, T.

    1999-01-01

    The uniform and smooth focal profile of the Nike KrF laser [S. Obenschain et al., Phys. Plasmas 3, 2098 (1996)] was used to ablatively accelerate 40 μm thick polystyrene planar targets with pulse shaping to minimize shock heating of the compressed material. The foils had imposed small-amplitude sinusoidal wave perturbations of 60, 30, 20, and 12.5 μm wavelength. The shortest wavelength is near the ablative stabilization cutoff for Rayleigh - Taylor growth. Modification of the saturated wave structure due to random laser imprint was observed. Excellent agreement was found between the two-dimensional simulations and experimental data for most cases where the laser imprint was not dominant. copyright 1999 American Institute of Physics

  19. The Magnetic Rayleigh-Taylor Instability in Astrophysical Discs

    Science.gov (United States)

    Contopoulos, I.; Kazanas, D.; Papadopoulos, D. B.

    2016-01-01

    This is our first study of the magnetic Rayleigh-Taylor instability at the inner edge of an astrophysical disc around a central back hole. We derive the equations governing small-amplitude oscillations in general relativistic ideal magnetodydrodynamics and obtain a criterion for the onset of the instability. We suggest that static disc configurations where magnetic field is held by the disc material are unstable around a Schwarzschild black hole. On the other hand, we find that such configurations are stabilized by the space-time rotation around a Kerr black hole. We obtain a crude estimate of the maximum amount of poloidal magnetic flux that can be accumulated around the centre, and suggest that it is proportional to the black hole spin. Finally, we discuss the astrophysical implications of our result for the theoretical and observational estimations of the black hole jet power.

  20. Taylor's law and body size in exploited marine ecosystems.

    Science.gov (United States)

    Cohen, Joel E; Plank, Michael J; Law, Richard

    2012-12-01

    Taylor's law (TL), which states that variance in population density is related to mean density via a power law, and density-mass allometry, which states that mean density is related to body mass via a power law, are two of the most widely observed patterns in ecology. Combining these two laws predicts that the variance in density is related to body mass via a power law (variance-mass allometry). Marine size spectra are known to exhibit density-mass allometry, but variance-mass allometry has not been investigated. We show that variance and body mass in unexploited size spectrum models are related by a power law, and that this leads to TL with an exponent slightly <2. These simulated relationships are disrupted less by balanced harvesting, in which fishing effort is spread across a wide range of body sizes, than by size-at-entry fishing, in which only fish above a certain size may legally be caught.

  1. Front propagation in Rayleigh-Taylor systems with reaction

    International Nuclear Information System (INIS)

    Scagliarini, A; Biferale, L; Sbragaglia, M; Mantovani, F; Pivanti, M; Schifano, S F; Tripiccione, R; Pozzati, F; Toschi, F

    2011-01-01

    A special feature of Rayleigh-Taylor systems with chemical reactions is the competition between turbulent mixing and the 'burning processes', which leads to a highly non-trivial dynamics. We studied the problem performing high resolution numerical simulations of a 2d system, using a thermal lattice Boltzmann (LB) model. We spanned the various regimes emerging at changing the relative chemical/turbulent time scales, from slow to fast reaction; in the former case we found numerical evidence of an enhancement of the front propagation speed (with respect to the laminar case), providing a phenomenological argument to explain the observed behaviour. When the reaction is very fast, instead, the formation of sharp fronts separating patches of pure phases, leads to an increase of intermittency in the small scale statistics of the temperature field.

  2. Taylor-Couette flow stability with toroidal magnetic field

    International Nuclear Information System (INIS)

    Shalybkov, D

    2005-01-01

    The linear stability of the dissipative Taylor-Couette flow with imposed azimuthal magnetic field is considered. Unlike to ideal flow, the magnetic field is fixed function of radius with two parameters only: a ratio of inner to outer cylinder radii and a ratio of the magnetic field values on outer and inner cylinders. The magnetic field with boundary values ratio greater than zero and smaller than inverse radii ratio always stabilizes the flow and called stable magnetic field below. The current free magnetic field is the stable magnetic field. The unstable magnetic field destabilizes every flow if the magnetic field (or Hartmann number) exceeds some critical value. This instability survives even without rotation (for zero Reynolds number). For the stable without the magnetic field flow, the unstable modes are located into some interval of the vertical wave numbers. The interval length is zero for critical Hartmann number and increases with increasing Hartmann number. The critical Hartmann numbers and the length of the unstable vertical wave numbers interval is the same for every rotation law. There are the critical Hartmann numbers for m = 0 sausage and m = 1 kink modes only. The critical Hartmann numbers are smaller for kink mode and this mode is the most unstable mode like to the pinch instability case. The flow stability do not depend on the magnetic Prandtl number for m = 0 mode. The same is true for critical Hartmann numbers for m = 0 and m = 1 modes. The typical value of the magnetic field destabilizing the liquid metal Taylor-Couette flow is order of 100 Gauss

  3. Cylindrical Taylor states conserving total absolute magnetic helicity

    Science.gov (United States)

    Low, B. C.; Fang, F.

    2014-09-01

    The Taylor state of a three-dimensional (3D) magnetic field in an upright cylindrical domain V is derived from first principles as an extremum of the total magnetic energy subject to a conserved, total absolute helicity Habs. This new helicity [Low, Phys. Plasmas 18, 052901 (2011)] is distinct from the well known classical total helicity and relative total helicity in common use to describe wholly-contained and anchored fields, respectively. A given field B, tangential along the cylindrical side of V, may be represented as a unique linear superposition of two flux systems, an axially extended system along V and a strictly transverse system carrying information on field-circulation. This specialized Chandrasekhar-Kendall representation defines Habs and permits a neat formulation of the boundary-value problem (BVP) for the Taylor state as a constant-α force-free field, treating 3D wholly-contained and anchored fields on the same conceptual basis. In this formulation, the governing equation is a scalar integro-partial differential equation (PDE). A family of series solutions for an anchored field is presented as an illustration of this class of BVPs. Past treatments of the constant-α field in 3D cylindrical geometry are based on a scalar Helmholtz PDE as the governing equation, with issues of inconsistency in the published field solutions discussed over time in the journal literature. The constant-α force-free equation reduces to a scalar Helmholtz PDE only as special cases of the 3D integro-PDE derived here. In contrast, the constant-α force-free equation and the scalar Helmholtz PDE are absolutely equivalent in the spherical domain as discussed in Appendix. This theoretical study is motivated by the investigation of the Sun's corona but the results are also relevant to laboratory plasmas.

  4. Experimental investigation of turbulent mixing by Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Youngs, D.L.

    1992-01-01

    A key feature of compressible turbulent mixing is the generation of vorticity via the ∇px ∇(1/ρ) term. This source of vorticity is also present in incompressible flows involving the mixing of fluids of different density, for example Rayleigh-Taylor unstable flows. This paper gives a summary of an experimental investigation of turbulent mixing at a plane boundary between two fluids, of densities ρ 1 , and ρ 2 . (ρ 1 > ρ 2 ) due to Rayleigh-Taylor instability. The two fluids are near incompressible and mixing occurs when an approximately constant acceleration, g, is applied normal to the interface with direction from fluid 2 to fluid 1. Full details of the experimental programme are given in a set of three reports. Some of the earlier experiments are also described by Read. Previous experimental work and much of the theoretical research has concentrated on studying the growth of the instability from a single wavelength perturbation rather than turbulent mixing. Notable exceptions are published in the Russian literature. A related process, turbulent mixing induced by the passage of shock waves though an interface between fluids of different density is described by Andronov et al. The major purpose of the experiments described here was to study the evolution of the instability from small random perturbations where it is found that large and larger structures appear as time proceeds. A novel technique was used to provide the desired acceleration. The two fluids were enclosed in a rectangular tank, the lighter fluid 2 initially resting on top of the denser fluid 1. One or more rocket motors were then used to drive the tank vertically downwards. The aim of the experimental programme is to provide data for the calibration of a turbulence model used to predict mixing in real situations

  5. Past temperature reconstructions from deep ice cores: relevance for future climate change

    Directory of Open Access Journals (Sweden)

    V. Masson-Delmotte

    2006-01-01

    Full Text Available Ice cores provide unique archives of past climate and environmental changes based only on physical processes. Quantitative temperature reconstructions are essential for the comparison between ice core records and climate models. We give an overview of the methods that have been developed to reconstruct past local temperatures from deep ice cores and highlight several points that are relevant for future climate change. We first analyse the long term fluctuations of temperature as depicted in the long Antarctic record from EPICA Dome C. The long term imprint of obliquity changes in the EPICA Dome C record is highlighted and compared to simulations conducted with the ECBILT-CLIO intermediate complexity climate model. We discuss the comparison between the current interglacial period and the long interglacial corresponding to marine isotopic stage 11, ~400 kyr BP. Previous studies had focused on the role of precession and the thresholds required to induce glacial inceptions. We suggest that, due to the low eccentricity configuration of MIS 11 and the Holocene, the effect of precession on the incoming solar radiation is damped and that changes in obliquity must be taken into account. The EPICA Dome C alignment of terminations I and VI published in 2004 corresponds to a phasing of the obliquity signals. A conjunction of low obliquity and minimum northern hemisphere summer insolation is not found in the next tens of thousand years, supporting the idea of an unusually long interglacial ahead. As a second point relevant for future climate change, we discuss the magnitude and rate of change of past temperatures reconstructed from Greenland (NorthGRIP and Antarctic (Dome C ice cores. Past episodes of temperatures above the present-day values by up to 5°C are recorded at both locations during the penultimate interglacial period. The rate of polar warming simulated by coupled climate models forced by a CO2 increase of 1% per year is compared to ice

  6. Measurement of air quality within storage domes in technical area 54, areas G and L

    International Nuclear Information System (INIS)

    Anderson, E.

    1994-01-01

    The concentrations of volatile organic compounds (VOCs) and tritium inside of storage domes at TA-54 were measured to assess worker exposure and support the Area G site characterization, including the Radioactive Air Emissions Management (RAEM) program. Samples were collected at 2-3 locations within Domes 48, 49, and 153 on up to six days during the summer of 1994. Samples were collected to evaluate three scenarios: (1) normal working activities with the domes open; (2) after domes were closed overnight; and (3) after domes were closed for three days. Eight-hour integrated samples were collected and analyzed in Radian's Austin laboratories. Tritium activities from 17.1 to 69,900 pCi/m 3 were measured. About two dozen individual VOCs were identified in each sample, but most of the concentration levels were very low (e.g.; 20%) than when the domes were closed only overnight. The data were used to generate estimated annual dome emission rates of 0.3 Ci/yr of tritium and less than 100 lbs/yr of VOCs. The measured VOC concentrations were collected during the warmest months of the year and therefore should represent worst-case air impacts

  7. Antarctic Ice-Sheet Mass Balance from Satellite Altimetry 1992 to 2001

    Science.gov (United States)

    Zwally, H. Jay; Brenner, Anita C.; Cornejo, Helen; Giovinetto, Mario; Saba, Jack L.; Yi, Donghui

    2003-01-01

    A major uncertainty in understanding the causes of the current rate of sea level rise is the potential contributions from mass imbalances of the Greenland and Antarctic ice sheets. Estimates of the current mass balance of the Antarctic ice sheet are derived from surface- elevation changes obtained from 9 years of ERS - 1 & 2 radar altimeter data. Elevation time-series are created from altimeter crossovers among 90-day data periods on a 50 km grid to 81.5 S. The time series are fit with a multivariate linear/sinusoidal function to give the average rate of elevation change (dH/dt). On the major Rome-Filchner, Ross, and Amery ice shelves, the W d t are small or near zero. In contrast, the ice shelves of the Antarctic Peninsula and along the West Antarctic coast appear to be thinning significantly, with a 23 +/- 3 cm per year surface elevation decrease on the Larsen ice shelf and a 65 +/- 4 cm per year decrease on the Dotson ice shelf. On the grounded ice, significant elevation decreases are obtained over most of the drainage basins of the Pine Island and Thwaites glaciers in West Antarctica and inland of Law Dome in East Antarctica. Significant elevation increases are observed within about 200 km of the coast around much of the rest of the ice sheet. Farther inland, the changes are a mixed pattern of increases and decreases with increases of a few centimeters per year at the highest elevations of the East Antarctic plateau. The derived elevation changes are combined with estimates of the bedrock uplift from several models to provide maps of ice thickness change. The ice thickness changes enable estimates of the ice mass balances for the major drainage basins, the overall mass balance, and the current contribution of the ice sheet to global sea level change.

  8. The Svalbard-Barents Sea ice-sheet - Historical, current and future perspectives

    Science.gov (United States)

    Ingólfsson, Ólafur; Landvik, Jon Y.

    2013-03-01

    The history of research on the Late Quaternary Svalbard-Barents Sea ice sheet mirrors the developments of ideas and the shifts of paradigms in glacial theory over the past 150 years. Since the onset of scientific research there in the early 19th Century, Svalbard has been a natural laboratory where ideas and concepts have been tested, and played an important (but rarely acknowledged) role in the break-through of the Ice Age theory in the 1870's. The history of how the scientific perception of the Svalbard-Barents sea ice sheet developed in the mid-20th Century also tells a story of how a combination of fairly scattered and often contradictory observational data, and through both deductive and inductive reasoning, could outline a major ice sheet that had left but few tangible fingerprints. Since the 1980's, with increased terrestrial stratigraphical data, ever more marine geological evidence and better chronological control of glacial events, our perception of the Svalbard-Barents Sea ice sheet has changed. The first reconstructions depicted it as a static, concentric, single-domed ice sheet, with ice flowing from an ice divide over the central northern Barents Sea that expanded and declined in response to large-scale, Late Quaternary climate fluctuations, and which was more or less in tune with other major Northern Hemisphere ice sheets. We now increasingly perceive it as a very dynamic, multidomed ice sheet, controlled by climate fluctuations, relative sea-level change, as well as subglacial topography, substrate properties and basal temperature. In this respect, the Svalbard-Barents Sea ice sheet will increasingly hold the key for understanding the dynamics and processes of how marine-based ice sheets build-up and decay.

  9. Longitudinal Biases in the Seychelles Dome Simulated by 34 Ocean-Atmosphere Coupled General Circulation Models

    Science.gov (United States)

    Nagura, M.; Sasaki, W.; Tozuka, T.; Luo, J.; Behera, S. K.; Yamagata, T.

    2012-12-01

    The upwelling dome of the southern tropical Indian Ocean is examined by using simulated results from 34 ocean-atmosphere coupled general circulation models (CGCMs) including those from the phase five of the Coupled Model Intercomparison Project (CMIP5). Among the current set of the 34 CGCMs, 12 models erroneously produce the upwelling dome in the eastern half of the basin while the observed Seychelles Dome is located in the southwestern tropical Indian Ocean (Figure 1). The annual mean Ekman pumping velocity is almost zero in the southern off-equatorial region in these models. This is in contrast with the observations that show Ekman upwelling as the cause of the Seychelles Dome. In the models that produce the dome in the eastern basin, the easterly biases are prominent along the equator in boreal summer and fall that cause shallow thermocline biases along the Java and Sumatra coasts via Kelvin wave dynamics and result in a spurious upwelling dome there. In addition, these models tend to overestimate (underestimate) the magnitude of annual (semiannual) cycle of thermocline depth variability in the dome region, which is another consequence of the easterly wind biases in boreal summer-fall. Compared to the CMIP3 models (Yokoi et al. 2009), the CMIP5 models are even worse in simulating the dome longitudes and magnitudes of annual and semiannual cycles of thermocline depth variability in the dome region. Considering the increasing need to understand regional impacts of climate modes, these results may give serious caveats to interpretation of model results and help in further model developments.; Figure 1: The longitudes of the shallowest annual-mean D20 in 5°S-12°S. The open and filled circles are for the observations and the CGCMs, respectively.

  10. Draft environmental assessment: Richton Dome site, Mississippi. Nuclear Waste Policy Act (Section 112)

    International Nuclear Information System (INIS)

    1984-12-01

    In February 1983, the US Department of Energy identified the Richton dome site as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Richton dome site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for Nuclear Waste Repositories. These evaluations are reported in this draft (EA), which is being issued for public review and comment. The DOE findings and determinations that are based on these evaluations are preliminary and subject to public review and comment. A final EA will be prepared after considering the comments received. On the basis of the evaluations reported in this draft EA, the DOE has found that the Richton dome site is not disqualified under the guidelines. The site is in the Gulf Interior Region of the Gulf Coastal Plain. This setting contains two other potentially acceptable sites - the Cypress Creek dome site and the Vacherie dome site. Although these other two sites appear to be suitable for site characterization, the DOE has concluded that the Richton dome site is the preferred site in the Gulf Interior Region. Furthermore, the DOE finds that the site is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is proposing to nominate the Richton dome site as one of five sites suitable for characterization. Having compared the Richton dome site with the other four sites proposed for nomination, the DOE has determined that the Richton dome site is not one of the three preferred sites for recommendation to the President as candidates for characterization

  11. Helicopter Icing Review.

    Science.gov (United States)

    1980-09-01

    helicopter (i.e. in an icing tunnel or engine test cell ) and therefore can be subjected to controlled icing where spe- cific problems can be safely...evaluation. 69 2.2.5.2 Ice Protection Systems Demonstration Many of the systems noted in 2.2.5.1 can be evaluated in icing test cells or icing wind tunnels...Figure 2-32 illustrates a typical rotor deice system control arrangement. 104 (N >4 A.dO INaH -E- C4) uo U En 9 E-1 H m I ~z O 04 04iH U 0 El4 E-f C E

  12. Modeling the Physical Multi-Phase Interactions of HNO3 Between Snow and Air on the Antarctic Plateau (Dome C) and coast (Halley)

    Science.gov (United States)

    Chan, Hoi Ga; Frey, Markus M.; King, Martin D.

    2017-04-01

    Nitrogen oxides (NOx = NO + NO2) emissions from nitrate (NO3-) photolysis in snow affect the oxidising capacity of the lower troposphere especially in remote regions of the high latitudes with low pollution levels. The porous structure of snowpack allows the exchange of gases with the atmosphere driven by physicochemical processes, and hence, snow can act as both source and sink of atmospheric chemical trace gases. Current models are limited by poor process understanding and often require tuning parameters. Here, two multi-phase physical models were developed from first principles constrained by observed atmospheric nitrate, HNO3, to describe the air-snow interaction of nitrate. Similar to most of the previous approaches, the first model assumes that below a threshold temperature, To, the air-snow grain interface is pure ice and above To, a disordered interface (DI) emerges assumed to be covering the entire grain surface. The second model assumes that Air-Ice interactions dominate over the entire temperature range below melting and that only above the eutectic temperature, liquid is present in the form of micropockets in grooves. The models are validated with available year-round observations of nitrate in snow and air at a cold site on the Antarctica Plateau (Dome C, 75°06'S, 123°33'E, 3233 m a.s.l.) and at a relatively warm site on the Antarctica coast (Halley, 75°35'S, 26°39'E, 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34), but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites without any tuning (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that air-snow interactions of nitrate in the winter are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain. In summer, however, the air-snow exchange of nitrate is mainly driven by solvation into liquid

  13. 78 FR 43751 - Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor

    Science.gov (United States)

    2013-07-19

    ... National Emergency With Respect to the Former Liberian Regime of Charles Taylor On July 22, 2004, by... regime of Charles Taylor pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706... constituted by the actions and policies of former Liberian President Charles Taylor and other persons, in...

  14. 3 CFR - Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor

    Science.gov (United States)

    2010-01-01

    ... to the Former Liberian Regime of Charles Taylor Presidential Documents Other Presidential Documents... of Charles Taylor On July 22, 2004, by Executive Order 13348, the President declared a national... to the former Liberian regime of Charles Taylor, pursuant to the International Emergency Economic...

  15. 76 FR 43799 - Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor

    Science.gov (United States)

    2011-07-21

    ...--Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor #0; #0; #0... Continuation of the National Emergency With Respect to the Former Liberian Regime of Charles Taylor On July 22... of Charles Taylor, pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706...

  16. 76 FR 24479 - In the Matter of the Taylor Lumber and Treating Superfund Site, Sheridan, Oregon, Amendment to...

    Science.gov (United States)

    2011-05-02

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9300-9] In the Matter of the Taylor Lumber and Treating... Taylor Lumber and Treating Site, which PWPO was acquiring, in exchange for several obligations related to...-553- 0705. Comments should reference the Taylor Lumber and Treating Superfund Site in Sheridan, Oregon...

  17. 75 FR 42281 - Continuation of the National Emergency With Respect To the Former Liberian Regime of Charles Taylor

    Science.gov (United States)

    2010-07-21

    ... National Emergency With Respect To the Former Liberian Regime of Charles Taylor On July 22, 2004, by... Taylor, pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706). The President... States constituted by the actions and policies of former Liberian President Charles Taylor and other...

  18. Ship detection in Sentinel-1 imagery using the h-dome transformation

    CSIR Research Space (South Africa)

    Schwegmann, CP

    2015-07-01

    Full Text Available is then processed to detect cluster centroids which indicate the ships’ positions. The following sections detail this procedure. 3.1. H-dome transform The H-dome transform is a method for finding local maxima, often used in the medical field for finding sub-cellular...) and comparing it to Fig. 2 (d) we no- tice that the brightest section of the ship can be seen much more clearly in (d). This is due to the property of the H- dome transform to highlight structures not typically visible (such as sub-cellular structures in [8...

  19. A history of semi-active laser dome and window materials

    Science.gov (United States)

    Sullivan, Roger M.

    2014-05-01

    Semi-Active Laser (SAL) guidance systems were developed starting in the mid-1960's and today form an important class of precision guided weapons. The laser wavelengths generally fall in the short wave infrared region of the spectrum. Relative to passive, image based, infrared seekers the optical demands placed on the domes or windows of SAL seekers is very modest, allowing the use of low cost, easily manufactured materials, such as polycarbonate. This paper will examine the transition of SAL window and dome science and technology from the laboratory to battlefield, with special emphasis on the story of polycarbonate domes.

  20. Ice slurry applications

    Energy Technology Data Exchange (ETDEWEB)

    Kauffeld, M. [Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133 Karlsruhe (Germany); Wang, M.J.; Goldstein, V. [Sunwell Technologies Inc., 180 Caster Avenue, Woodbridge, L4L 5Y (Canada); Kasza, K.E. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2010-12-15

    The role of secondary refrigerants is expected to grow as the focus on the reduction of greenhouse gas emissions increases. The effectiveness of secondary refrigerants can be improved when phase changing media are introduced in place of single-phase media. Operating at temperatures below the freezing point of water, ice slurry facilitates several efficiency improvements such as reductions in pumping energy consumption as well as lowering the required temperature difference in heat exchangers due to the beneficial thermo-physical properties of ice slurry. Research has shown that ice slurry can be engineered to have ideal ice particle characteristics so that it can be easily stored in tanks without agglomeration and then be extractable for pumping at very high ice fraction without plugging. In addition ice slurry can be used in many direct contact food and medical protective cooling applications. This paper provides an overview of the latest developments in ice slurry technology. (author)

  1. Autonomous Aerial Ice Observation for Ice Defense

    Directory of Open Access Journals (Sweden)

    Joakim Haugen

    2014-10-01

    Full Text Available One of the tasks in ice defense is to gather information about the surrounding ice environment using various sensor platforms. In this manuscript we identify two monitoring tasks known in literature, namely dynamic coverage and target tracking, and motivate how these tasks are relevant in ice defense using RPAS. An optimization-based path planning concept is outlined for solving these tasks. A path planner for the target tracking problem is elaborated in more detail and a hybrid experiment, which consists of both a real fixed-wing aircraft and simulated objects, is included to show the applicability of the proposed framework.

  2. Arctic landfast sea ice

    Science.gov (United States)

    Konig, Christof S.

    Landfast ice is sea ice which forms and remains fixed along a coast, where it is attached either to the shore, or held between shoals or grounded icebergs. Landfast ice fundamentally modifies the momentum exchange between atmosphere and ocean, as compared to pack ice. It thus affects the heat and freshwater exchange between air and ocean and impacts on the location of ocean upwelling and downwelling zones. Further, the landfast ice edge is essential for numerous Arctic mammals and Inupiat who depend on them for their subsistence. The current generation of sea ice models is not capable of reproducing certain aspects of landfast ice formation, maintenance, and disintegration even when the spatial resolution would be sufficient to resolve such features. In my work I develop a new ice model that permits the existence of landfast sea ice even in the presence of offshore winds, as is observed in mature. Based on viscous-plastic as well as elastic-viscous-plastic ice dynamics I add tensile strength to the ice rheology and re-derive the equations as well as numerical methods to solve them. Through numerical experiments on simplified domains, the effects of those changes are demonstrated. It is found that the modifications enable landfast ice modeling, as desired. The elastic-viscous-plastic rheology leads to initial velocity fluctuations within the landfast ice that weaken the ice sheet and break it up much faster than theoretically predicted. Solving the viscous-plastic rheology using an implicit numerical method avoids those waves and comes much closer to theoretical predictions. Improvements in landfast ice modeling can only verified in comparison to observed data. I have extracted landfast sea ice data of several decades from several sources to create a landfast sea ice climatology that can be used for that purpose. Statistical analysis of the data shows several factors that significantly influence landfast ice distribution: distance from the coastline, ocean depth, as

  3. Fluid Mechanics of Taylor Bubbles and Slug Flows in Vertical Channels

    International Nuclear Information System (INIS)

    Anglart, Henryk; Podowski, Michael Z.

    2002-01-01

    Fluid mechanics of Taylor bubbles and slug flows is investigated in vertical, circular channels using detailed, three-dimensional computational fluid dynamics simulations. The Volume of Fluid model with the interface-sharpening algorithm, implemented in the commercial CFX4 code, is used to predict the shape and velocity of Taylor bubbles moving along a vertical channel. Several cases are investigated, including both a single Taylor bubble and a train of bubbles rising in water. It is shown that the potential flow solution underpredicts the water film thickness around Taylor bubbles. Furthermore, the computer simulations that are performed reveal the importance of properly modeling the three-dimensional nature of phenomena governing the motion of Taylor bubbles. Based on the present results, a new formula for the evaluation of bubble shape is derived. Both the shape of Taylor bubbles and the bubble rise velocity predicted by the proposed model agree well with experimental observations. Furthermore, the present model shows good promise in predicting the coalescence of Taylor bubbles

  4. Experimental results on improved JARE deep ice core drill-Experiments in Rikubetsu, Hokkaido in 2002 -

    Directory of Open Access Journals (Sweden)

    Takao Kameda

    2002-07-01

    Full Text Available Deep ice coring to bedrock (3028m in depth at Dome Fuji Station is planned during three successive summer seasons starting from 2003/2004. An improved JARE deep ice core drill (12.2m in length and 3.8m in maximum core length was developed in December 2001 for the ice coring at Dome Fuji. In January/February of 2002,we performed experiments on drill performance using artificial ice blocks in Rikubetsu, Hokkaido. In this paper, we outline the experiment and report the results. It was found through the experiment that an ice core of 3.8m length was smoothly obtained by the improved drill with three screws in the chip chamber and cutting pitch of 5mm/cycle. About 45000 small holes 1.2mm in diameter were made on the surface of the chip chamber. These small holes enabled liquid to circulate between cutters and outside of the drill through the chip chamber in the drill. The dry density of the chips was 440 to 500kg/m^3 and the chip recovery rate during ice coring was 65 to 91%. A check valve installed at the bottom of the chip chamber to prevent outflow of chips from the drill was not tested enough, but more durability is needed for the valve. The newly developed motor system and core catchers of the drill worked perfectly. The average coring speed was 24.5cm/min with cutting pitch of 5mm/cycle. The average power consumption during ice coring was 171W.

  5. Studies of the suitability of salt domes in east Texas basin for geologic isolation of nuclear wastes

    International Nuclear Information System (INIS)

    Kreitler, C.W.

    1979-01-01

    The suitability of salt domes in the east Texas basin (Tyler basin), Texas, for long-term isolation of nulear wastes is being evaluated. The major issues concern hydrogeologic and tectonic stability of the domes and potential natural resources in the basin. These issues are being approached by integration of dome-specific and regional hydrogeolgic, geologic, geomorphic, and remote-sensing investigations. Hydrogeologic studies are evaluating basinal hydrogeology and ground-water flow around the domes in order to determine the degree to which salt domes may be dissolving, their rates of solution, and the orientation of saline plumes in the fresh-water aquifers. Subsurface geologic studies are being conducted: (1) to determine the size and shape of specific salt domes, the geology of the strata immediately surrounding the domes, and the regional geology of the east Texas basin; (2) to understand the geologic history of dome growth and basin infilling; and (3) to evaluate potential natural resources. Geomorphic and surficial geology studies are determining whether there has been any dome growth or tectonic movement in the basin during the Quaternary. Remote-sensing studies are being conducted to determine: (1) if dome uplift has altered regional lineation patterns in Quaternary sediments; and (2) whether drainage density indicates Quaternary structural movement. On the basis of the screening criteria of Brunton et al (1978), Oakwood and Keechi domes have been chosen as possible candidate domes. Twenty-three domes have been eliminated because of insufficient size, too great a depth to salt, major hydrocarbon production, or previous use (such as liquid propane storage or salt mining or brining). Detailed geologic, hydrogeologic, and geomorphic investigations are now being conducted around Oakwood and Keechi salt domes

  6. The Development of M Cells in Peyer’s Patches Is Restricted to Specialized Dome-Associated Crypts

    Science.gov (United States)

    Gebert, Andreas; Fassbender, Susanne; Werner, Kerstin; Weissferdt, Annikka

    1999-01-01

    It is controversial whether the membranous (M) cells of the Peyer’s patches represent a separate cell line or develop from enterocytes under the influence of lymphocytes on the domes. To answer this question, the crypts that produce the dome epithelial cells were studied and the distribution of M cells over the domes was determined in mice. The Ulex europaeus agglutinin was used to detect M cells in mouse Peyer’s patches. Confocal microscopy with lectin-gold labeling on ultrathin sections, scanning electron microscopy, and laminin immuno-histochemistry were combined to characterize the cellular composition and the structure of the dome-associated crypts and the dome epithelium. In addition, the sites of lymphocyte invasion into the dome epithelium were studied after removal of the epithelium using scanning electron microscopy. The domes of Peyer’s patches were supplied with epithelial cells that derived from two types of crypt: specialized dome-associated crypts and ordinary crypts differing not only in shape, size, and cellular composition but also in the presence of M cell precursors. When epithelial cells derived from ordinary crypts entered the domes, they formed converging radial strips devoid of M cells. In contrast to the M cells, the sites where lymphocytes invaded the dome epithelium were not arranged in radial strips, but randomly distributed over the domes. M cell development is restricted to specialized dome-associated crypts. Only dome epithelial cells that derive from these specialized crypts differentiate into M cells. It is concluded that M cells represent a separate cell line that is induced in the dome-associated crypts by still unknown, probably diffusible lymphoid factors. PMID:10329609

  7. Removable cruciform for ice condenser ice basket

    International Nuclear Information System (INIS)

    Scrabis, C.M.; Mazza, G.E.; Golick, L.R.; Pomaibo, P.

    1987-01-01

    A removable cruciform for use in an ice basket having a generally cylindrical sidewall defining a central, vertical axis of the ice basket and plural, generally annular retaining rings secured to the interior of the cylindrical sidewall of the ice basket at predetermined, spaced elevations throughout the axial height of the ice basket is described comprising: a pair of brackets, each comprising a central, base portion having parallel longitudinal edges and a pair of integral legs extending at corresponding angles relative to the base portion from the perspective parallel longitudinal edges thereof; a pair of support plate assemblies secured to and extending in parallel, spaced relationship from one of the pair of brackets; a pair of slide support plates secured to the other of the pair of brackets and extending therefrom in spaced, parallel relationship; and spring means received within the housing and engaging the base portions of the brackets and applying a resilient biasing force thereto for maintaining the spaced relationship thereof

  8. Ice cream structure modification by ice-binding proteins.

    Science.gov (United States)

    Kaleda, Aleksei; Tsanev, Robert; Klesment, Tiina; Vilu, Raivo; Laos, Katrin

    2018-04-25

    Ice-binding proteins (IBPs), also known as antifreeze proteins, were added to ice cream to investigate their effect on structure and texture. Ice recrystallization inhibition was assessed in the ice cream mixes using a novel accelerated microscope assay and the ice cream microstructure was studied using an ice crystal dispersion method. It was found that adding recombinantly produced fish type III IBPs at a concentration 3 mg·L -1 made ice cream hard and crystalline with improved shape preservation during melting. Ice creams made with IBPs (both from winter rye, and type III IBP) had aggregates of ice crystals that entrapped pockets of the ice cream mixture in a rigid network. Larger individual ice crystals and no entrapment in control ice creams was observed. Based on these results a model of ice crystals aggregates formation in the presence of IBPs was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Water-quality data for aquifers, streams, and lakes in the vicinity of Keechi, Mount Sylvan, Oakwood, and Palestine salt domes, northeast Texas salt-dome basin

    International Nuclear Information System (INIS)

    Carr, J.E.; Halasz, S.J.; Liscum, F.

    1980-11-01

    This report contains water-quality data for aquifers, streams, and lakes in the vicinity of Keechi, Mount Sylvan, Oakwood, and Palestine Salt Domes in the northeast Texas salt-dome basin. Water-quality data were compiled for aquifers in the Wilcox Group, the Carrizo Sand, and the Queen City Sand. The data include analyses for dissolved solids, pH, temperature, hardness, calcium, magnesium, sodium, bicarbonate, chloride, and sulfate. Water-quality and streamflow data were obtained from 63 surface-water sites in the vicinity of the domes. These data include water discharge, specific conductance, pH, water temperature, and dissolved oxygen. Samples were collected at selected sites for analysis of principal and selected minor dissolved constituents

  10. Ablation front rayleigh taylor dispersion curve in indirect drive

    International Nuclear Information System (INIS)

    Budil, K.S.; Lasinski, B.; Edwards, M.J.; Wan, A.S.; Remington, B.A.; Weber, S.V.; Glendinning, S.G.; Suter, L.; Stry, P.

    2000-01-01

    The Rayleigh-Taylor (RT) instability, which occurs when a lower-density fluid accelerates a higher-density layer, is common in nature. At an ablation front a sharp reduction in the growth rate of the instability at short wave-lengths can occur, in marked contrast to the classical case where growth rates are highest at the shortest wavelengths. Theoretical and numerical investigations of the ablative RT instability are numerous and differ considerably on the level of stabilization expected. We present here the results of a series of laser experiments designed to probe the roll-over and cutoff region of the ablation-front RT dispersion curve in indirect drive. Aluminum foils with imposed sinusoidal perturbations ranging in wavelength from 10 to 70 pm were ablatively accelerated with a radiation drive generated in a gold cylindrical hohlraum. A strong shock wave compresses the package followed by an ∼2 ns period of roughly constant acceleration and the experiment is diagnosed via face-on radiography. Perturbations with wavelengths (ge) 20 (micro)m experienced substantial growth during the acceleration phase while shorter wavelengths showed a sharp drop off in overall growth. These experimental results compared favorably to calculations with a 2-D radiation-hydrodynamics code, however, the growth is significantly affected by the rippled shock launched by the drive. We performed numerical simulations to elucidate the influence of the rippled shock wave on the eventual growth of the perturbations, allowing comparisons to the analytic model developed by Betti et al. This combination of experiments, simulations and analytic modeling illustrates the qualitative simplicity yet quantitative complexity of the compressible RT instability. We have measured the Rayleigh-Taylor (RT) dispersion curve for a radiatively-driven sample in a series of experiments on the Nova laser facility. Planar aluminum foils were ablatively-accelerated and the subsequent perturbation growth was

  11. The Interpretation Of Metaphor Found In 20 Songs Of Taylor Swift

    OpenAIRE

    Desriani, Shella

    2015-01-01

    This paper entitled The interpretation of metaphor found in 20 of taylor swift. this paper discuss the types and meaning of metaphor in the lyrics of the song taylor swift. The purpose of this paper is to analyze types of metaphor in the form of simile, personification and hyperbole contained in the lyrics of the song taylor swift. In this paper the authors wrote the paper used the method of literature, collect some data from some books, and the internet. the lyric which contained metaphors i...

  12. Quantum effects on the Rayleigh-Taylor instability in a horizontal inhomogeneous rotating plasma

    International Nuclear Information System (INIS)

    Hoshoudy, G. A.

    2009-01-01

    The Rayleigh-Taylor instability is studied analytically in inhomogeneous plasma rotating uniformly in an external transverse magnetic field. The influence of the quantum mechanism is considered. For a stratified layer the linear growth rate is obtained. Some special cases that isolate the effect of various parameters on the growth rate of the Rayleigh-Taylor instability are discussed. It is shown that for some cases, the presence of the external transverse magnetic field beside the quantum effect will bring about more stability on the Rayleigh-Taylor instability.

  13. Effect of FLR correction on Rayleigh -Taylor instability of quantum and stratified plasma

    International Nuclear Information System (INIS)

    Sharma, P.K.; Tiwari, Anita; Argal, Shraddha; Chhajlani, R.K.

    2013-01-01

    The Rayleigh Taylor instability of stratified incompressible fluids is studied in presence of FLR Correction and quantum effects in bounded medium. The Quantum magneto hydrodynamic equations of the problem are solved by using normal mode analysis method. A dispersion relation is carried out for the case where plasma is bounded by two rigid planes z = 0 and z = h. The dispersion relation is obtained in dimensionless form to discuss the growth rate of Rayleigh Taylor instability in presence of FLR Correction and quantum effects. The stabilizing or destabilizing behavior of quantum effect and FLR correction on the Rayleigh Taylor instability is analyzed. (author)

  14. Hyperthyroidism with dome-and-dart T wave: A case report: A care-compliant article.

    Science.gov (United States)

    Lai, Ping; Yuan, Jing-Ling; Xue, Jin-Hua; Qiu, Yue-Qun

    2017-02-01

    Dome-and-dart T waves (or bifid T waves) are a rare phenomenon in the surface electrocardiogram. These wave forms are mainly observed in patients with congenital heart disease such as atrial septal defect and ventricular septal defect. And hyperthyroidism who presented with an electrocardiogram that had dome-and-dart T waves in a precordial lead is never been reported. The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Hyperthyroidism. Methimazole. All symptoms were alleviated. Dome-and-dart or bifid T waves have been reported in the conventional 12-lead electrocardiograms in some patients with congenital heart disease. The case illustrated here, to the best of our knowledge, dome-and-dart or bifid T waves may associate with hyperthyroidism patients.

  15. Hyperthyroidism with dome-and-dart T wave: A case report

    Science.gov (United States)

    Lai, Ping; Yuan, Jing-ling; Xue, Jin-hua; Qiu, Yue-qun

    2017-01-01

    Abstract Rationale: Dome-and-dart T waves (or bifid T waves) are a rare phenomenon in the surface electrocardiogram. These wave forms are mainly observed in patients with congenital heart disease such as atrial septal defect and ventricular septal defect. And hyperthyroidism who presented with an electrocardiogram that had dome-and-dart T waves in a precordial lead is never been reported. Patient concerns: The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Diagnoses: Hyperthyroidism. Interventions: Methimazole. Outcomes: All symptoms were alleviated. Lessons: Dome-and-dart or bifid T waves have been reported in the conventional 12-lead electrocardiograms in some patients with congenital heart disease. The case illustrated here, to the best of our knowledge, dome-and-dart or bifid T waves may associate with hyperthyroidism patients. PMID:28178156

  16. The thermo-mechanical behaviour of a salt dome with a heat-generating waste repository

    International Nuclear Information System (INIS)

    Janssen, L.G.J.; Prij, J.; Kevenaar, J.W.A.M.; Jong, C.J.T.; Klok, J.; Beemsterboer, C.

    1984-01-01

    This report reviews the analytical work on the disposal of radioactive waste in salt domes performed at ECN in the period 1 January 1980 to 31 December 1982. Chapter 4 in the main report covers the global temperature and deformation analyses of the salt dome and the surrounding rocks. The attached three topical reports cover self-contained parts of the study. The computer program TASTE developed to analyse, at acceptable cost and with, for engineering purposes, sufficient accuracies, the temperature rises in the salt dome due to the stored heat-generating waste is described in Annex 1. Annex 2 gives a description of the extended finite element program GOLIA. The program has been extended to make it suitable for the creep analysis of salt domes with repositories of heat-generating waste. The study on the closing and sealing of boreholes wit heat-generating waste is reported in Annex 3

  17. Three Functions of the School Newspaper: The Truth Shop, The Persuasion Podium, The Pleasure Dome.

    Science.gov (United States)

    Campbell, Laurence R.

    This Quill and Scroll Study, which is illustrated with numerous tables, concerns the following subjects: The School Newspaper as a Truth Shop; The School Newspaper as a Pleasure Dome; and The School Newspaper as a Persuasion Podium. (DB)

  18. Dome-shaped High Tibial Osteotomy: A Long-term Follow-up Study

    Directory of Open Access Journals (Sweden)

    Hongsen Chiang

    2006-01-01

    Conclusion: Dome-shaped HTO is a durable time-buying procedure for patients with unicompartmental medial gonarthrosis, and can avoid subsequent development of patella baja that may complicate further prosthetic arthroplasty.

  19. Mud Volcanoes - Analogs to Martian Cones and Domes (by the Thousands!)

    Science.gov (United States)

    Allen, Carlton C.; Oehler, Dorothy

    2010-01-01

    Mud volcanoes are mounds formed by low temperature slurries of gas, liquid, sediments and rock that erupt to the surface from depths of meters to kilometers. They are common on Earth, with estimates of thousands onshore and tens of thousands offshore. Mud volcanoes occur in basins with rapidly-deposited accumulations of fine-grained sediments. Such settings are ideal for concentration and preservation of organic materials, and mud volcanoes typically occur in sedimentary basins that are rich in organic biosignatures. Domes and cones, cited as possible mud volcanoes by previous authors, are common on the northern plains of Mars. Our analysis of selected regions in southern Acidalia Planitia has revealed over 18,000 such features, and we estimate that more than 40,000 occur across the area. These domes and cones strongly resemble terrestrial mud volcanoes in size, shape, morphology, associated flow structures and geologic setting. Geologic and mineralogic arguments rule out alternative formation mechanisms involving lava, ice and impacts. We are studying terrestrial mud volcanoes from onshore and submarine locations. The largest concentration of onshore features is in Azerbaijan, near the western edge of the Caspian Sea. These features are typically hundreds of meters to several kilometers in diameter, and tens to hundreds of meters in height. Satellite images show spatial densities of 20 to 40 eruptive centers per 1000 square km. Many of the features remain active, and fresh mud flows as long as several kilometers are common. A large field of submarine mud volcanoes is located in the Gulf of Cadiz, off the Atlantic coasts of Morocco and Spain. High-resolution sonar bathymetry reveals numerous km-scale mud volcanoes, hundreds of meters in height. Seismic profiles demonstrate that the mud erupts from depths of several hundred meters. These submarine mud volcanoes are the closest morphologic analogs yet found to the features in Acidalia Planitia. We are also conducting

  20. Volcanic synchronisation of the EPICA-DC and TALDICE ice cores for the last 42 kyr BP

    Directory of Open Access Journals (Sweden)

    M. Severi

    2012-03-01

    Full Text Available The age scale synchronisation between the Talos Dome and the EPICA Dome C ice cores was carried on through the identification of several common volcanic signatures. This paper describes the rigorous method, using the signature of volcanic sulphate, which was employed for the last 42 kyr of the record. Using this tight stratigraphic link, we transferred the EDC age scale to the Talos Dome ice core, producing a new age scale for the last 12 kyr. We estimated the discrepancies between the modelled TALDICE-1 age scale and the new scale during the studied period, by evaluating the ratio R of the apparent duration of temporal intervals between pairs of isochrones. Except for a very few cases, R ranges between 0.8 and 1.2, corresponding to an uncertainty of up to 20% in the estimate of the time duration in at least one of the two ice cores. At this stage our approach does not allow us to unequivocally identify which of the models is affected by errors, but, taking into account only the historically known volcanic events, we found that discrepancies up to 200 yr appear in the last two millennia in the TALDICE-1 model, while our new age scale shows a much better agreement with the volcanic absolute horizons. Thus, we propose for the Talos Dome ice core a new age scale (covering the whole Holocene obtained by a direct transfer, via our stratigraphic link, from the EDC modelled age scale by Lemieux-Dudon et al. (2010.

  1. Authentic Astronomical Discovery in Planetariums: Bringing Data to Domes

    Science.gov (United States)

    Wyatt, Ryan Jason; Subbarao, Mark; Christensen, Lars; Emmons, Ben; Hurt, Robert

    2018-01-01

    Planetariums offer a unique opportunity to disseminate astronomical discoveries using data visualization at all levels of complexity: the technical infrastructure to display data and a sizeable cohort of enthusiastic educators to interpret results. “Data to Dome” is an initiative the International Planetarium Society to develop our community’s capacity to integrate data in fulldome planetarium systems—including via open source software platforms such as WorldWide Telescope and OpenSpace. We are cultivating a network of planetarium professionals who integrate data into their presentations and share their content with others. Furthermore, we propose to shorten the delay between discovery and dissemination in planetariums. Currently, the “latest science” is often presented days or weeks after discoveries are announced, and we can shorten this to hours or even minutes. The Data2Dome (D2D) initiative, led by the European Southern Observatory, proposes technical infrastructure and data standards that will streamline content flow from research institutions to planetariums, offering audiences a unique opportunity to access to the latest astronomical data in near real time.

  2. Dome diagnostics system of optical parameters and characteristics of LEDs

    Science.gov (United States)

    Peretyagin, Vladimir S.; Pavlenko, Nikita A.

    2017-09-01

    Scientific and technological progress of recent years in the production of the light emitting diodes (LEDs) has led to the expansion of areas of their application from the simplest systems to high precision lighting devices used in various fields of human activity. However, development and production (especially mass production) of LED lighting devices are impossible without a thorough analysis of its parameters and characteristics. There are many ways and devices for analysis the spatial, energy and colorimetric parameters of LEDs. The most methods are intended for definition only one parameter (for example, luminous flux) or one characteristic (for example, the angular distribution of energy or the spectral characteristics). Besides, devices used these methods are intended for measuring parameters in only one point or plane. This problem can be solved by using a dome diagnostics system of optical parameters and characteristics of LEDs, developed by specialists of the department OEDS chair of ITMO University in Russia. The paper presents the theoretical aspects of the analysis of LED's spatial (angular), energy and color parameters by using mentioned of diagnostics system. The article also presents the results of spatial), energy and color parameters measurements of some LEDs brands.

  3. Basic repository environmental assessment design basis, Richton Dome site

    International Nuclear Information System (INIS)

    1988-01-01

    This study examines the engineering factors and costs associated with the construction, operation, and decommissioning of a high-level nuclear waste repository in salt in the Gulf Interior Region at Richton Dome in Perry County, Mississippi. The study assumes a repository capacity of 36,000 metric tons of heavy metal (MTHM) of unreprocessed spent fuel and 36,000 MTHM of commercial high-level reprocessing waste, along with 7,020 canisters of defense high-level reprocessing waste and associated quantities of remote-and contact-handled transuranic waste (TRU). With the exception of TRU, all the waste forms are placed in 300- to 1,000-year-life carbon-steel waste packages in a collocated waste handling and packaging facility (WHPF), which is also described. The construction, operation, and decommissioning of the proposed repository is estimated to cost approximately $4.49 billion. Costs include those for the WHPF, engineering, and contingency, but exclude waste form assembly and shipment to the site and waste package fabrication and shipment to the site. These costs reflect the relative average wage rates of the region and the relatively easy access to the site. Construction would require an estimated 6.25 years. Engineering factors and costs are not strongly influenced by environmental considerations. 52 refs., 24 figs., 20 tabs

  4. Development and operation of the Above Dome Inspection Rig (ADIR)

    International Nuclear Information System (INIS)

    Dickson, R.P.; Moorby, J.

    1984-01-01

    Hinkley Point 'B' is developing its remote inspection equipment in order to be able to inspect reactor internals adequately without manned vessel entry. The Above Dome Inspection Rig has been built to allow a number of inspection systems to be introduced and operated within the reactor. The ability to introduce, use and remove inspection equipment without the necessity to lift the rig from the reactor is a vital feature in the speed achieved in completing inspections quickly. Television was selected for the A.D.M. because it has significant advantages in terms of operational convenience. However the quality of image obtained in terms of information available compares unfavourably with photography. The sharpness of a photographic image is largely dictated by the chemical structure of the emulsion, whereas video is limited by the picture line structure and bandwidth. The need for a photographic system for in reactor use is therefore essential for high definition inspection requirements. The first inspection system that has been developed for the ADIR is the Telefilm camera. It consists of a Hasselblad photographic camera using an Insight television camera looking through its viewfinder. The characteristics of television and photography have been combined. (author)

  5. Structure and evolution of an active resurgent dome evidenced by geophysical investigations: The Yenkahe dome-Yasur volcano system (Siwi caldera, Vanuatu)

    Science.gov (United States)

    Brothelande, E.; Lénat, J.-F.; Chaput, M.; Gailler, L.; Finizola, A.; Dumont, S.; Peltier, A.; Bachèlery, P.; Barde-Cabusson, S.; Byrdina, S.; Menny, P.; Colonge, J.; Douillet, G. A.; Letort, J.; Letourneur, L.; Merle, O.; Di Gangi, F.; Nakedau, D.; Garaebiti, E.

    2016-08-01

    In this contribution, we focus on one of the most active resurgences on Earth, that of the Yenkahe dome in the Siwi caldera (Tanna Island, Vanuatu), which is associated with the persistently active Yasur volcano. Gravity and magnetic surveys have been carried out over the past few years in the area, as well as electrical methods including electrical resistivity tomography (ERT), time domain electro-magnetics (TDEM) and self-potential (SP). These investigations were completed by thermometry, CO2 soil gas measurements, field observations and sampling. This multi-method approach allows geological structures within the caldera to be identified, as well as associated hydrothermal features. The global structure of the caldera is deduced from gravity data, which shows the caldera rim as a high density structure. Large lava fields, emplaced before and after the onset of resurgence, are evidenced by combined gravity, magnetic and resistivity signals. In the middle of the caldera, the Yenkahe dome apparently results from a combination of volcanic and tectonic events, showing that lava extrusion and resurgence have been operating simultaneously or alternately during the Siwi caldera post-collapse history. There is a clear distinction between the western and eastern parts of the dome. The western part is older and records the growth of an initial volcanic cone and the formation of a small caldera. This small caldera (paleo-Yasur caldera), partially filled with lava flows, is the present-day focus of volcanic activity and associated fluid circulation and alteration. The eastern part of the dome is presumably younger, and is characterized by intense, extensive hydrothermal alteration and activity. Its northern part is covered by lava flow piles and exhibits a shallow hydrothermal zone in ERT. The southern part has hydrothermal alteration and activity extending at least down to the base of the resurgent dome. This part of the dome is built up of low cohesion rock and is thus

  6. DOMe: A deduplication optimization method for the NewSQL database backups.

    Directory of Open Access Journals (Sweden)

    Longxiang Wang

    Full Text Available Reducing duplicated data of database backups is an important application scenario for data deduplication technology. NewSQL is an emerging database system and is now being used more and more widely. NewSQL systems need to improve data reliability by periodically backing up in-memory data, resulting in a lot of duplicated data. The traditional deduplication method is not optimized for the NewSQL server system and cannot take full advantage of hardware resources to optimize deduplication performance. A recent research pointed out that the future NewSQL server will have thousands of CPU cores, large DRAM and huge NVRAM. Therefore, how to utilize these hardware resources to optimize the performance of data deduplication is an important issue. To solve this problem, we propose a deduplication optimization method (DOMe for NewSQL system backup. To take advantage of the large number of CPU cores in the NewSQL server to optimize deduplication performance, DOMe parallelizes the deduplication method based on the fork-join framework. The fingerprint index, which is the key data structure in the deduplication process, is implemented as pure in-memory hash table, which makes full use of the large DRAM in NewSQL system, eliminating the performance bottleneck problem of fingerprint index existing in traditional deduplication method. The H-store is used as a typical NewSQL database system to implement DOMe method. DOMe is experimentally analyzed by two representative backup data. The experimental results show that: 1 DOMe can reduce the duplicated NewSQL backup data. 2 DOMe significantly improves deduplication performance by parallelizing CDC algorithms. In the case of the theoretical speedup ratio of the server is 20.8, the speedup ratio of DOMe can achieve up to 18; 3 DOMe improved the deduplication throughput by 1.5 times through the pure in-memory index optimization method.

  7. Potential for creation of a salt dome following disposal of radioactive waste in a salt layer

    International Nuclear Information System (INIS)

    Charo, L.; Habib, P.

    1987-01-01

    The study aims at quantifying the possibility of creation of a salt dome from a salt layer in which heat-emitting radioactive waste would be buried. Volume 1 describes the results of numerical computer simulations, and of laboratory-scale models in centrifuges. Volume 2 envisages, in a geological perspective, the origin of salt domes, the mechanisms of their formation, and the associated parameters [fr

  8. Design Of a Fixed-Dome Ferrocement Biodigester Built Partiall y Underground

    OpenAIRE

    Marianela de la Caridad Ortiz Alvarez; Hugo Rafael Wainshtok Rivas; Henry Hernández Sotomayor

    2016-01-01

    The analysis, structural design and constructive sequence of a fixed-dome biodigester built partially underground and using ferrocement as construction material under normal work conditions is in this paper developed. The biodigester capacity is 24 m3 and it is composed by a semispherical dome (cover), cylindricalwalls (body) and a circular slab(bottom). The biodigester using ferrocement as construction materialis in agreement with the service guaranty requirements settled for the established...

  9. Potential for creation of a salt dome following disposal of radioactive waste in a salt layer

    International Nuclear Information System (INIS)

    Fries, G.

    1987-01-01

    The study aims at quantifying the possibility of creation of a salt dome from a salt layer in which heat-emitting radioactive waste would be buried. Volume 1 describes the results of numerical computer simulations, and of laboratory-scale models in centrifuges. Volume 2 envisages, in a geological perspective, the origin of salt domes, the mechanisms of thei formation, and the associated parameters [fr

  10. Seismicity associated with dome growth and collapse at the Soufriere Hills Volcano, Montserrat

    Science.gov (United States)

    Miller, A.D.; Stewart, R.C.; White, R.A.; Luckett, R.; Baptie, B.J.; Aspinall, W.P.; Latchman, J.L.; Lynch, L.L.; Voight, B.

    1998-01-01

    Varied seismicity has accompanied growth and collapse of the lava dome of the Soufriere Hills Volcano, Montserrat. Earthquakes have been classified as either volcano-tectonic, long-period or hybrid, and daily variations in the numbers of events have mapped changes in the style of eruption. Repetitive hybrid earthquakes were common during the first months of dome growth. In July 1996 the style of seismicity changed and regular short-lived hybrid earthquake swarms became common. This change was probably caused by an increase in the magma flux. Earthquake swarms have preceded almost all major dome collapses, and have accompanied cyclical deformation, thought to be due to a built-up of pressure in the upper conduit which is later released by magma moving into the dome.Varied seismicity has accompanied growth and collapse of the lava dome of the Soufriere Hills Volcano, Montserrat. Earthquakes have been classified as either volcano-tectonic, long-period or hybrid, and daily variations in the numbers of events have mapped changes in the style of eruption. Repetitive hybrid earthquakes were common during the first months of dome growth. In July 1996 the style of seismicity changed and regular, short-lived hybrid earthquake swarms became common. This change was probably caused by an increase in the magma flux. Earthquake swarms have preceded almost all major dome collapses, and have accompanied cyclical deformation, thought to be due to a build-up of pressure in the upper conduit which is later released by magma moving into the dome.

  11. Direct Numerical Simulations of Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Livescu, D; Wei, T; Petersen, M R

    2011-01-01

    The development of the Rayleigh-Taylor mixing layer is studied using data from an extensive new set of Direct Numerical Simulations (DNS), performed on the 0.5 Petaflops, 150k compute cores BG/L Dawn supercomputer at Lawrence Livermore National Laboratory. This includes a suite of simulations with grid size of 1024 2 × 4608 and Atwood number ranging from 0.04 to 0.9, in order to examine small departures from the Boussinesq approximation as well as large Atwood number effects, and a high resolution simulation of grid size 4096 2 × 4032 and Atwood number of 0.75. After the layer width had developed substantially, additional branched simulations have been run under reversed and zero gravity conditions. While the bulk of the results will be published elsewhere, here we present preliminary results on: 1) the long-standing open question regarding the discrepancy between the numerically and experimentally measured mixing layer growth rates and 2) mixing characteristics.

  12. Regimes of the magnetized Rayleigh endash Taylor instability

    International Nuclear Information System (INIS)

    Winske, D.

    1996-01-01

    Hybrid simulations with kinetic ions and massless fluid electrons are used to investigate the linear and nonlinear behavior of the magnetized Rayleigh endash Taylor instability in slab geometry with the plasma subject to a constant gravity. Three regimes are found, which are determined by the magnitude of the complex frequency ω=ω r +iγ. For |ω| i (Ω i = ion gyrofrequency), one finds the typical behavior of the usual fluid regime, namely the development of open-quote open-quote mushroom-head close-quote close-quote spikes and bubbles in the density and a strongly convoluted boundary between the plasma and magnetic field, where the initial gradient is not relaxed much. A second regime, where |ω|∼0.1Ω i , is characterized by the importance of the Hall term. Linearly, the developing flute modes are more finger-like and tilted along the interface; nonlinearly, clump-like structures form, leading to a significant broadening of the interface. The third regime is characterized by unmagnetized ion behavior, with |ω|∼Ω i . Density clumps, rather than flutes, form in the linear stage, while nonlinearly, longer-wavelength modes that resemble those in fluid regime dominate. Finite Larmor radius stabilization of short-wavelength modes is observed in each regime. copyright 1996 American Institute of Physics

  13. Perioperative versus postoperative measurement of Taylor Spatial Frame mounting parameters.

    Science.gov (United States)

    Sökücü, Sami; Demir, Bilal; Lapçin, Osman; Yavuz, Umut; Kabukçuoğlu, Yavuz S

    2014-01-01

    The aim of this study was to determine the differences, if any, between application parameters for the Taylor Spatial Frame (TSF) system obtained during surgery under fluoroscopy and after surgery from digital radiography. This retrospective study included 17 extremities of 15 patients (8 male, 7 female; mean age: 21.9 years, range: 10 to 55 years) who underwent TSF after deformity and fracture. Application parameters measured by fluoroscopy at the end of surgery after mounting the fixator were compared with parameters obtained from anteroposterior and lateral digital radiographs taken 1 day after surgery. Fixator was applied to the femur in 8 patients, tibia in 6 and radius in 3. Mean time to removal of the frame was 3.5 (range: 3 to 7) months. Mean perioperative anteroposterior, lateral and axial frame offsets of patients were 9.1 (range: 3 to 20) mm, 18.1 (range: 5 to 37) mm and 95.3 (range: 25 to 155) mm, respectively. Mean postoperative anteroposterior, lateral and axial frame offset radiographs were 11.8 (range: 2 to 30) mm, 18 (range: 6 to 47) mm and 109.5 (range: 28 to 195) mm, respectively. There was no statistically significant difference between the groups (p>0.05). While measurements taken during operation may lengthen the duration in the operation room, fluoroscopy may provide better images and is easier to perform than digital radiography. On the other hand, there is no difference between measurements taken during perioperative fluoroscopy and postoperative digital radiography.

  14. New mitigation schemes of the ablative Rayleigh-Taylor instability

    International Nuclear Information System (INIS)

    Azechi, H.; Shiraga, H.; Nakai, M.; Shigemori, K.; Fujioka, S.; Sakaiya, T.; Tamari, Y.; Ohtani, K.; Watari, T.; Murakami, M.; Sunahara, A.; Nagatomo, H.; Nishihara, K.; Miyanaga, N.; Izawa, Y.; Ohnishi, N.

    2005-01-01

    The Rayleigh-Taylor (RT) instability with material ablation through the unstable interface is the key physics that determines success or failure of inertial fusion energy (IFE) generation, as the RT instability potentially quenches ignition and burn by disintegrating the IFE target. We present two suppression schemes of the RT growth without significant degradation of the target density. The first scheme is to generate double ablation structure in high-Z doped plastic targets. In addition to the electron ablation surface, a new ablation surface is created by x-ray radiation from the high-Z ions. Contrary to the previous thought, the electron ablation surface is almost completely stabilized by extremely high flow velocity. On the other hand, the RT instability on the radiative ablation surface is significantly moderated. The second is to enhance the nonlocal nature of the electron heat transport by illuminating the target with long wavelength laser light, whereas the high ablation pressure is generated by irradiating short wavelength laser light. The significant suppression of the RT instability may increase the possibility of impact ignition which uses a high velocity fuel colliding with a preformed main fuel. (author)

  15. Potential Flow Model for Compressible Stratified Rayleigh-Taylor Instability

    Science.gov (United States)

    Rydquist, Grant; Reckinger, Scott; Owkes, Mark; Wieland, Scott

    2017-11-01

    The Rayleigh-Taylor Instability (RTI) is an instability that occurs when a heavy fluid lies on top of a lighter fluid in a gravitational field, or a gravity-like acceleration. It occurs in many fluid flows of a highly compressive nature. In this study potential flow analysis (PFA) is used to model the early stages of RTI growth for compressible fluids. In the localized region near the bubble tip, the effects of vorticity are negligible, so PFA is applicable, as opposed to later stages where the induced velocity due to vortices generated from the growth of the instability dominate the flow. The incompressible PFA is extended for compressibility effects by applying the growth rate and the associated perturbation spatial decay from compressible linear stability theory. The PFA model predicts theoretical values for a bubble terminal velocity for single-mode compressible RTI, dependent upon the Atwood (A) and Mach (M) numbers, which is a parameter that measures both the strength of the stratification and intrinsic compressibility. The theoretical bubble terminal velocities are compared against numerical simulations. The PFA model correctly predicts the M dependence at high A, but the model must be further extended to include additional physics to capture the behavior at low A. Undergraduate Scholars Program - Montana State University.

  16. GRAVITATIONALLY UNSTABLE FLAMES: RAYLEIGH-TAYLOR STRETCHING VERSUS TURBULENT WRINKLING

    International Nuclear Information System (INIS)

    Hicks, E. P.; Rosner, R.

    2013-01-01

    In this paper, we provide support for the Rayleigh-Taylor-(RT)-based subgrid model used in full-star simulations of deflagrations in Type Ia supernovae explosions. We use the results of a parameter study of two-dimensional direct numerical simulations of an RT unstable model flame to distinguish between the two main types of subgrid models (RT or turbulence dominated) in the flamelet regime. First, we give scalings for the turbulent flame speed, the Reynolds number, the viscous scale, and the size of the burning region as the non-dimensional gravity (G) is varied. The flame speed is well predicted by an RT-based flame speed model. Next, the above scalings are used to calculate the Karlovitz number (Ka) and to discuss appropriate combustion regimes. No transition to thin reaction zones is seen at Ka = 1, although such a transition is expected by turbulence-dominated subgrid models. Finally, we confirm a basic physical premise of the RT subgrid model, namely, that the flame is fractal, and thus self-similar. By modeling the turbulent flame speed, we demonstrate that it is affected more by large-scale RT stretching than by small-scale turbulent wrinkling. In this way, the RT instability controls the flame directly from the large scales. Overall, these results support the RT subgrid model.

  17. Wave driven magnetic reconnection in the Taylor problem

    International Nuclear Information System (INIS)

    Fitzpatrick, Richard; Bhattacharjee, Amitava; Ma Zhiwei; Linde, Timur

    2003-01-01

    An improved Laplace transform theory is developed in order to investigate the initial response of a stable slab plasma equilibrium enclosed by conducting walls to a suddenly applied wall perturbation in the so-called Taylor problem. The novel feature of this theory is that it does not employ asymptotic matching. If the wall perturbation is switched on slowly compared to the Alfven time then the plasma response eventually asymptotes to that predicted by conventional asymptotic matching theory. However, at early times there is a compressible Alfven wave driven contribution to the magnetic reconnection rate which is not captured by asymptotic matching theory, and leads to a significant increase in the reconnection rate. If the wall perturbation is switched on rapidly compared to the Alfven time then strongly localized compressible Alfven wave-pulses are generated which bounce backward and forward between the walls many times. Each instance these wave-pulses cross the resonant surface they generate a transient surge in the reconnection rate. The maximum pulse driven reconnection rate can be much larger than that predicted by conventional asymptotic matching theory

  18. Modal model for the nonlinear multimode Rayleigh endash Taylor instability

    International Nuclear Information System (INIS)

    Ofer, D.; Alon, U.; Shvarts, D.; McCrory, R.L.; Verdon, C.P.

    1996-01-01

    A modal model for the Rayleigh endash Taylor (RT) instability, applicable at all stages of the flow, is introduced. The model includes a description of nonlinear low-order mode coupling, mode growth saturation, and post-saturation mode coupling. It is shown to significantly extend the range of applicability of a previous model proposed by Haan, to cases where nonlinear mode generation is important. Using the new modal model, we study the relative importance of mode coupling at late nonlinear stages and resolve the difference between cases in which mode generation assumes a dominant role, leading to the late time inverse cascade of modes and loss of memory of initial conditions, and cases where mode generation is not important and memory of initial conditions is retained. Effects of finite density ratios (Atwood number A<1) are also included in the model and the difference between various measures of the mixing zone penetration depth for A<1 is discussed. copyright 1996 American Institute of Physics

  19. An Instability in Stratified Taylor-Couette Flow

    Science.gov (United States)

    Swinney, Harry

    2015-11-01

    In the late 1950s Russell Donnelly began conducting experiments at the University of Chicago on flow between concentric rotating cylinders, and his experiments together with complementary theory by his collaborator S. Chandrasekhar did much to rekindle interest in the flow instability discovered and studied by G.I. Taylor (1923). The present study concerns an instability in a concentric cylinder system containing a fluid with an axial density gradient. In 2005 Dubrulle et al. suggested that a `stratorotational instability' (SRI) in this system could provide insight into instability and angular momentum transport in astrophysical accretion disks. In 2007 the stratorotational instability was observed in experiments by Le Bars and Le Gal. We have conducted an experiment on the SRI in a concentric cylinder system (radius ratio η = 0 . 876) with buoyancy frequency N / 2 π = 0.25, 0.50, or 0.75 Hz. For N = 0.75 Hz we observe the SRI onset to occur for Ωouter /Ωinner > η , contrary to the prediction of Shalybkov and Rüdiger. Research conducted with Bruce Rodenborn and Ruy Ibanez.

  20. Ion evaporation from the surface of a Taylor cone.

    Science.gov (United States)

    Higuera, F J

    2003-07-01

    An analysis is carried out of the electric field-induced evaporation of ions from the surface of a polar liquid that is being electrosprayed in a vacuum. The high-field cone-to-jet transition region of the electrospray, where ion evaporation occurs, is studied taking advantage of its small size and neglecting the inertia of the liquid and the space charge around the liquid. Evaporated ions and charged drops coexist in a range of flow rates, which is investigated numerically. The structure of the cone-to-jet transition comprises: a hydrodynamic region where the nearly equipotential surface of the liquid departs from a Taylor cone and becomes a jet; a slender region where the radius of the jet decreases and the electric field increases while the pressure and the viscous stress balance the electric stress at the surface; the ion evaporation region of high, nearly constant field; and a charged, continuously strained jet that will eventually break into drops. Estimates of the ion and drop contributions to the total, conduction-limited current show that the first of these contributions dominates for small flow rates, while most of the mass is still carried by the drops.

  1. Distributions of cranial pathologies provide evidence for head-butting in dome-headed dinosaurs (Pachycephalosauridae.

    Directory of Open Access Journals (Sweden)

    Joseph E Peterson

    Full Text Available Pachycephalosaurids are small, herbivorous dinosaurs with domed skulls formed by massive thickening of the cranial roof. The function of the dome has been a focus of debate: the dome has variously been interpreted as the product of sexual selection, as an adaptation for species recognition, or as a weapon employed in intraspecific combat, where it was used in butting matches as in extant ungulates. This last hypothesis is supported by the recent identification of cranial pathologies in pachycephalosaurids, which appear to represent infections resulting from trauma. However, the frequency and distribution of pathologies have not been studied in a systematic fashion. Here, we show that pachycephalosaurids are characterized by a remarkably high incidence of cranial injury, where 22% of specimens have lesions on the dome. Frequency of injury shows no significant difference between different genera, but flat-headed morphs (here interpreted as juveniles or females lack lesions. Mapping of injuries onto a digitial pachycephalosaurid skull shows that although lesions are distributed across the dome, they cluster near the apex, which is consistent with the hypothesis that the dome functioned for intraspecific butting matches.

  2. Atmospheric scintillation at Dome C, Antarctica: implications for photometry and astrometry

    Science.gov (United States)

    Kenyon, S.; Lawrence, J.; Ashley, M. C. B.; Storey, J. W. V.; Tokovinin, A.; Fossat, E.

    2006-08-01

    Night-time turbulence profiles of the atmosphere above Dome C, Antarctica, were measured during 2004, using a MASS instrument. We compare this data with turbulence profiles above Cerro Tololo and Cerro Pachon, also measured with a MASS, and find, with the exception of the owest layer, that Dome C has significantly less turbulence. In addition, the integrated at turbulence 16 km above Dome C is always less than the median values at the two Chilean sites. Using average wind speed profiles, we assess the photometric noise produced by scintillation, and the atmospheric contribution to the error budget in narrow angle differential astrometry. In comparison with the two mid-latitude sites in Chile, Dome C offers a potential gain of about 3.6 in both photometric precision (for long integrations) and narrow-angle astrometry precision. Although the data from Dome C cover a fairly limited time frame, they lend strong support to expectations that Dome C will offer significant advantages for photometric and astrometric studies.

  3. Experimental study and numerical optimization of tensegrity domes - A case study

    Science.gov (United States)

    Winkelmann, Karol; Kłos, Filip; Rąpca, Mateusz

    2018-01-01

    The paper deals with the design, experimental analysis and numerical optimization of tensegrity dome models. Two structures are analyzed - a Geiger system dome (preliminary dome), with PVC-U bars and PA6/PP/PET tendons and a Fuller system dome (target dome), with wooden bars and steel cables as tendons. All used materials are experimentally tested in terms of Young's modulus and yield stress values, the compressed bars are also tested for the limit length demarcating the elastic buckling from plastic failure. The data obtained in experiments is then implemented in SOFiSTiK commercial software FE model. The model's geometrical parameters are considered uniform random variables. Geometrically and materially nonlinear analysis is carried out. Based on the obtained structural response (displacements), a Monte Carlo simulation - based approach is incorporated for both structural design point formulation and the SLS requirements fulfillment analysis. Finally, an attempt is made to erect the Fuller dome model in order to compare the numerical results of an experimentally-derived model with the in situ measurements of an actual structure.

  4. Percutaneous Ethanol Injection via an Artificially Induced Right Hydrothorax for Hepatocellular Carcinoma in the Hepatic Dome

    International Nuclear Information System (INIS)

    Kume, Akimichi; Nimura, Yuji; Kamiya, Junichi; Nagino, Masato; Kito, Yasushi

    2003-01-01

    To evaluate the efficacy of sonographically (US) guided percutaneous ethanol injection (PEI) via an artificially induced right hydrothorax (transthoracic PEI) to treat US-invisible hepatocellular carcinoma (HCC) in the hepatic dome. Five cirrhotic patients with US-invisible HCC in the hepatic dome, who were poor surgical candidates, underwent transthoracic PEI. An artificial right hydrothorax was created by instilling 500 ml saline, and absolute ethanol was injected transhydrothoracically into the hepatic dome lesion under local anesthesia. The success and complications were assessed radiologically. The patients were followed up serologically and radiologically for 12-44 (mean 28.4) months. Twenty-five hydrothoraces were induced. All hydrothoraces enabled US visualization of the entire hepatic dome. Eight of the nine small lesions were treated successfully by the treatment. Two of the three local recurrences were eradicated by repeat transthoracic PEI. One large lesion was treated by a combination of transthoracic and regular PEI. The only complication was one clinically insignificant pneumothorax. Induction of a right hydrothorax is feasible and safe. The hydrothorax enables US visualization of the entire hepatic dome and permits US-guided PEI for HCC in the hepatic dome that otherwise would not be possible

  5. Distributions of cranial pathologies provide evidence for head-butting in dome-headed dinosaurs (Pachycephalosauridae).

    Science.gov (United States)

    Peterson, Joseph E; Dischler, Collin; Longrich, Nicholas R

    2013-01-01

    Pachycephalosaurids are small, herbivorous dinosaurs with domed skulls formed by massive thickening of the cranial roof. The function of the dome has been a focus of debate: the dome has variously been interpreted as the product of sexual selection, as an adaptation for species recognition, or as a weapon employed in intraspecific combat, where it was used in butting matches as in extant ungulates. This last hypothesis is supported by the recent identification of cranial pathologies in pachycephalosaurids, which appear to represent infections resulting from trauma. However, the frequency and distribution of pathologies have not been studied in a systematic fashion. Here, we show that pachycephalosaurids are characterized by a remarkably high incidence of cranial injury, where 22% of specimens have lesions on the dome. Frequency of injury shows no significant difference between different genera, but flat-headed morphs (here interpreted as juveniles or females) lack lesions. Mapping of injuries onto a digitial pachycephalosaurid skull shows that although lesions are distributed across the dome, they cluster near the apex, which is consistent with the hypothesis that the dome functioned for intraspecific butting matches.

  6. Final report on decommissioning boreholes and wellsite restoration, Gulf Coast Interior Salt Domes of Mississippi

    International Nuclear Information System (INIS)

    1989-04-01

    In 1978, eight salt domes in Texas, Louisiana, and Mississippi were identified for study as potential locations for a nuclear waste repository as part of the National Waste Terminal Storage (NWTS) program. Three domes were selected in Mississippi for ''area characterization'' phase study as follows: Lampton Dome near Columbia, Cypress Creek Dome near New Augusta, and Richton Dome near Richton. The purpose of the studies was to acquire geologic and geohydrologic information from shallow and deep drilling investigations to enable selection of sites suitable for more intensive study. Eleven deep well sites were selected for multiple-well installations to acquire information on the lithologic and hydraulic properties of regional aquifers. In 1986, the Gulf Coast salt domes were eliminated from further consideration for repository development by the selection of three candidate sites in other regions of the country. In 1987, well plugging and restoration of these deferred sites became a closeout activity. The primary objectives of this activity are to plug and abandon all wells and boreholes in accordance with state regulations, restore all drilling sites to as near original condition as feasible, and convey to landowners any wells on their property that they choose to maintain. This report describes the activities undertaken to accomplish these objectives, as outlines in Activity Plan 1--2, ''Activity Plan for Well Plugging and Site Restoration of Test Hole Sites in Mississippi.''

  7. A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development.

    Science.gov (United States)

    Xiao, Ying; Thoresen, Daniel T; Miao, Lingling; Williams, Jonathan S; Wang, Chaochen; Atit, Radhika P; Wong, Sunny Y; Brownell, Isaac

    2016-07-01

    The Sonic hedgehog (Shh) signaling pathway regulates developmental, homeostatic, and repair processes throughout the body. In the skin, touch domes develop in tandem with primary hair follicles and contain sensory Merkel cells. The developmental signaling requirements for touch dome specification are largely unknown. We found dermal Wnt signaling and subsequent epidermal Eda/Edar signaling promoted Merkel cell morphogenesis by inducing Shh expression in early follicles. Lineage-specific gene deletions revealed intraepithelial Shh signaling was necessary for Merkel cell specification. Additionally, a Shh signaling agonist was sufficient to rescue Merkel cell differentiation in Edar-deficient skin. Moreover, Merkel cells formed in Fgf20 mutant skin where primary hair formation was defective but Shh production was preserved. Although developmentally associated with hair follicles, fate mapping demonstrated Merkel cells primarily originated outside the hair follicle lineage. These findings suggest that touch dome development requires Wnt-dependent mesenchymal signals to establish reciprocal signaling within the developing ectoderm, including Eda signaling to primary hair placodes and ultimately Shh signaling from primary follicles to extrafollicular Merkel cell progenitors. Shh signaling often demonstrates pleiotropic effects within a structure over time. In postnatal skin, Shh is known to regulate the self-renewal, but not the differentiation, of touch dome stem cells. Our findings relate the varied effects of Shh in the touch dome to the ligand source, with locally produced Shh acting as a morphogen essential for lineage specification during development and neural Shh regulating postnatal touch dome stem cell maintenance.

  8. A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development.

    Directory of Open Access Journals (Sweden)

    Ying Xiao

    2016-07-01

    Full Text Available The Sonic hedgehog (Shh signaling pathway regulates developmental, homeostatic, and repair processes throughout the body. In the skin, touch domes develop in tandem with primary hair follicles and contain sensory Merkel cells. The developmental signaling requirements for touch dome specification are largely unknown. We found dermal Wnt signaling and subsequent epidermal Eda/Edar signaling promoted Merkel cell morphogenesis by inducing Shh expression in early follicles. Lineage-specific gene deletions revealed intraepithelial Shh signaling was necessary for Merkel cell specification. Additionally, a Shh signaling agonist was sufficient to rescue Merkel cell differentiation in Edar-deficient skin. Moreover, Merkel cells formed in Fgf20 mutant skin where primary hair formation was defective but Shh production was preserved. Although developmentally associated with hair follicles, fate mapping demonstrated Merkel cells primarily originated outside the hair follicle lineage. These findings suggest that touch dome development requires Wnt-dependent mesenchymal signals to establish reciprocal signaling within the developing ectoderm, including Eda signaling to primary hair placodes and ultimately Shh signaling from primary follicles to extrafollicular Merkel cell progenitors. Shh signaling often demonstrates pleiotropic effects within a structure over time. In postnatal skin, Shh is known to regulate the self-renewal, but not the differentiation, of touch dome stem cells. Our findings relate the varied effects of Shh in the touch dome to the ligand source, with locally produced Shh acting as a morphogen essential for lineage specification during development and neural Shh regulating postnatal touch dome stem cell maintenance.

  9. Seismic experiments on Showa-Shinzan lava dome using firework shots

    Science.gov (United States)

    Miyamachi, Hiroki; Watanabe, Hidefumi; Moriya, Takeo; Okada, Hiromu

    1987-11-01

    Seismic experiments were conducted on Showa-Shinzan, a parasitic lava dome of volcano Usu, Hokkaido, which was formed during 1943 1945 activity. Since we found that firework shots fired on the ground can effectively produce seismic waves, we placed many seismometers on and around the dome during the summer festivals in 1984 and 1985. The internal structure had been previously studied using a prospecting technique employing dynamite blasts in 1954. The measured interval velocity across the dome in 1984 ranges 1.8 2.2 km/s drastically low compared to the results (3.0 4.0 km/s) in 1954; in addition, the velocity is 0.3 0.5 km/s higher than that in the surrounding area. The variation of the observed first arrival amplitudes can be explained by geometrical spreading in the high velocity lava dome. These observations show a marked change in the internal physical state of the dome corresponding to a drop in the measured highest temperature at fumaroles on the dome from 800°C in 1947 to 310°C in 1986.

  10. Features of Bayou Choctaw SPR caverns and internal structure of the salt dome.

    Energy Technology Data Exchange (ETDEWEB)

    Munson, Darrell E.

    2007-07-01

    The intent of this study is to examine the internal structure of the Bayou Choctaw salt dome utilizing the information obtained from graphical representations of sonar survey data of the internal cavern surfaces. Many of the Bayou Choctaw caverns have been abandoned. Some existing caverns were purchased by the Strategic Petroleum Reserve (SPR) program and have rather convoluted histories and complex cavern geometries. In fact, these caverns are typically poorly documented and are not particularly constructive to this study. Only two Bayou Choctaw caverns, 101 and 102, which were constructed using well-controlled solutioning methods, are well documented. One of these was constructed by the SPR for their use while the other was constructed and traded for another existing cavern. Consequently, compared to the SPR caverns of the West Hackberry and Big Hill domes, it is more difficult to obtain a general impression of the stratigraphy of the dome. Indeed, caverns of Bayou Choctaw show features significantly different than those encountered in the other two SPR facilities. In the number of abandoned caverns, and some of those existing caverns purchased by the SPR, extremely irregular solutioning has occurred. The two SPR constructed caverns suggest that some sections of the caverns may have undergone very regular solutioning to form uniform cylindrical shapes. Although it is not usually productive to speculate, some suggestions that point to the behavior of the Bayou Choctaw dome are examined. Also the primary differences in the Bayou Choctaw dome and the other SPR domes are noted.

  11. Some aspects of the development of NW-German salt domes

    International Nuclear Information System (INIS)

    Jaritz, W.

    1980-01-01

    Aspects of the development of salt structures that may be of some importance to the safety of a final disposal site for radioactive waste are salt ascent and salt dissolution at the surface. The geological history of the salt domes is described in terms of the dissolution of the salt at the dome surface. In many cases it can be distinguished whether dissolution was caused by the ascent of the salt into strata containing groundwater by diapirism or by epeirogenic uplift or both. The salt domes of Wesendorf, Heide, and Marne are used as examples in a discussion of the transition from dissolution to the deposition of a cover of impermeable sediments. Moreover, the development of the Gorleben salt dome is described. The author's studies show the average rate of uplift of the NW-German salt domes in the diapiric stage to have ranged from a little less than 0.1 to about 0.5 mm per year. For salt domes in later stages, the rate of uplift is several hundredths of a millimeter per year at most. (orig.) [de

  12. Aircraft Icing Handbook. (Update)

    Science.gov (United States)

    1993-01-01

    Report 1946-1947, U. S. Air Material Command Tech. Rept. 5676. Findeisen , W., *Meteorological Commentary of D (air) 1209, Icing,* Germany, Reichsamt fur...Wetterdienst, Forschungs-und Krfahrungsberichte, Ser. a, No. 29, 1943. Findeisen , W., *Meteorological-Physical Limitations of Icing on the Atmosphere...Apparatus for Measurement,’ Harvard - Mt. Washington Icing Research Report 1946-1947, U. S. Air Material Command Tech. Rept. 5676.. Findeisen , W., "The

  13. Safe Loads on Ice Sheets (Ice Engineering. Number 13)

    National Research Council Canada - National Science Library

    Haynes, F. D; Carey, Kevin L; Cattabriga, Gioia

    1996-01-01

    Every winter, ice sheets that grow on lakes and rivers in northern states are used for ice roads, ice bridges, construction platforms, airstrips, and recreational activities, It becomes very important...

  14. Solving the riddle of interglacial temperatures over the last 1.5 million years with a future IPICS "Oldest Ice" ice core

    Science.gov (United States)

    Fischer, Hubertus

    2014-05-01

    time period in Antarctica, is not an easy task. Based on a simple ice and heat flow model and glaciological observations (Fischer et al., Climate of the Past, 2013), we conclude that sites in the vicinity of major domes and saddle positions on the East Antarctic Plateau will most likely have such old ice in store and represent the best study areas for dedicated reconnaissance studies in the near future. In contrast to previous ice core drill site selections, however, significantly reduced ice thickness is required to avoid bottom melting. The most critical parameter is the largely unknown geothermal heat flux at the bottom of the ice sheet. For example for the geothermal heat flux and accumulation conditions at Dome C, an ice thickness lower than but close to about 2500 m would be required to find 1.5 My old ice. If sites with lower geothermal heat flux can be found, also a higher ice thickness is allowed, alleviating the problem of potential flow disturbances in the bottom-most ice to affect a 1.5 Myr climate record.

  15. Direct numerical simulation of the Rayleigh-Taylor instability with the spectral element method

    International Nuclear Information System (INIS)

    Zhang Xu; Tan Duowang

    2009-01-01

    A novel method is proposed to simulate Rayleigh-Taylor instabilities using a specially-developed unsteady three-dimensional high-order spectral element method code. The numerical model used consists of Navier-Stokes equations and a transport-diffusive equation. The code is first validated with the results of linear stability perturbation theory. Then several characteristics of the Rayleigh-Taylor instabilities are studied using this three-dimensional unsteady code, including instantaneous turbulent structures and statistical turbulent mixing heights under different initial wave numbers. These results indicate that turbulent structures of Rayleigh-Taylor instabilities are strongly dependent on the initial conditions. The results also suggest that a high-order numerical method should provide the capability of simulating small scale fluctuations of Rayleigh-Taylor instabilities of turbulent flows. (authors)

  16. Slavnov-Taylor1.0: A Mathematica package for computation in BRST formalism

    CERN Document Server

    Picariello, Marco; Picariello, Marco; Torrente-Lujan, Emilio

    2004-01-01

    Slavnov-Taylor1.0 is a Mathematica package which allows us to perform automatic simbolic computation in BRST formalism. This article serves as a self-contained guide to prospective users, and indicates the conventions and approximations used.

  17. Civil-Military Relations and Gen. Maxwell Taylor: Getting It Right and Getting It Wrong

    National Research Council Canada - National Science Library

    Tart, Randal

    1997-01-01

    ... are paid. In the first situation, Taylor got his civil-military relations right, even though he fought a losing battle with President Eisenhower over Ike's dangerous defense strategy of 'massive retaliation...

  18. Rayleigh Taylor instability of two superposed compressible fluids in un-magnetized plasma

    International Nuclear Information System (INIS)

    Sharma, P K; Tiwari, A; Argal, S; Chhajlani, R K

    2014-01-01

    The linear Rayleigh Taylor instability of two superposed compressible Newtonian fluids is discussed with the effect of surface tension which can play important roles in space plasma. As in both the superposed Newtonian fluids, the system is stable for potentially stable case and unstable for potentially unstable case in the present problem also. The equations of the problem are solved by normal mode method and a dispersion relation is obtained for such a system. The behaviour of growth rate is examined in the presence of surface tension and it is found that the surface tension has stabilizing influence on the Rayleigh Taylor instability of two superposed compressible fluids. Numerical analysis is performed to show the effect of sound velocity and surface tension on the growth rate of Rayleigh Taylor instability. It is found that both parameters have stabilizing influence on the growth rate of Rayleigh Taylor instability.

  19. Normalization of the parameterized Courant-Snyder matrix for symplectic factorization of a parameterized Taylor map

    International Nuclear Information System (INIS)

    Yan, Y.T.

    1991-01-01

    The transverse motion of charged particles in a circular accelerator can be well represented by a one-turn high-order Taylor map. For particles without energy deviation, the one-turn Taylor map is a 4-dimensional polynomials of four variables. The four variables are the transverse canonical coordinates and their conjugate momenta. To include the energy deviation (off-momentum) effects, the map has to be parameterized with a smallness factor representing the off-momentum and so the Taylor map becomes a 4-dimensional polynomials of five variables. It is for this type of parameterized Taylor map that a mehtod is presented for converting it into a parameterized Dragt-Finn factorization map. Parameterized nonlinear normal form and parameterized kick factorization can thus be obtained with suitable modification of the existing technique

  20. Direct Numerical Simulation of the Rayleigh−Taylor Instability with the Spectral Element Method

    International Nuclear Information System (INIS)

    Xu, Zhang; Duo-Wang, Tan

    2009-01-01

    A novel method is proposed to simulate Rayleigh−Taylor instabilities using a specially-developed unsteady three-dimensional high-order spectral element method code. The numerical model used consists of Navier–Stokes equations and a transport-diffusive equation. The code is first validated with the results of linear stability perturbation theory. Then several characteristics of the Rayleigh−Taylor instabilities are studied using this three-dimensional unsteady code, including instantaneous turbulent structures and statistical turbulent mixing heights under different initial wave numbers. These results indicate that turbulent structures of Rayleigh–Taylor instabilities are strongly dependent on the initial conditions. The results also suggest that a high-order numerical method should provide the capability of simulating small scale fluctuations of Rayleigh−Taylor instabilities of turbulent flows. (fundamental areas of phenomenology (including applications))