Science.gov

Sample records for high gravity levels

  1. The GRAVITY instrument software/high-level software

    NASA Astrophysics Data System (ADS)

    Burtscher, Leonard; Wieprecht, Ekkehard; Ott, Thomas; Kok, Yitping; Yazici, Senol; Anugu, Narsireddy; Dembet, Roderick; Fedou, Pierre; Lacour, Sylvestre; Ott, Jürgen; Paumard, Thibaut; Lapeyrere, Vincent; Kervella, Pierre; Abuter, Roberto; Pozna, Eszter; Eisenhauer, Frank; Blind, Nicolas; Genzel, Reinhard; Gillessen, Stefan; Hans, Oliver; Haug, Marcus; Haussmann, Frank; Kellner, Stefan; Lippa, Magdalena; Pfuhl, Oliver; Sturm, Eckhard; Weber, Johannes; Amorim, Antonio; Brandner, Wolfgang; Rousselet-Perraut, Karine; Perrin, Guy S.; Straubmeier, Christian; Schöller, Markus

    2014-07-01

    GRAVITY is the four-beam, near-infrared, AO-assisted, fringe tracking, astrometric and imaging instrument for the Very Large Telescope Interferometer (VLTI). It is requiring the development of one of the most complex instrument software systems ever built for an ESO instrument. Apart from its many interfaces and interdependencies, one of the most challenging aspects is the overall performance and stability of this complex system. The three infrared detectors and the fast reflective memory network (RMN) recorder contribute a total data rate of up to 20 MiB/s accumulating to a maximum of 250 GiB of data per night. The detectors, the two instrument Local Control Units (LCUs) as well as the five LCUs running applications under TAC (Tools for Advanced Control) architecture, are interconnected with fast Ethernet, RMN fibers and dedicated fiber connections as well as signals for the time synchronization. Here we give a simplified overview of all subsystems of GRAVITY and their interfaces and discuss two examples of high-level applications during observations: the acquisition procedure and the gathering and merging of data to the final FITS file.

  2. High-frequency analysis of Earth gravity field models based on terrestrial gravity and GPS/levelling data: a case study in Greece

    NASA Astrophysics Data System (ADS)

    Papanikolaou, T. D.; Papadopoulos, N.

    2015-06-01

    The present study aims at the validation of global gravity field models through numerical investigation in gravity field functionals based on spherical harmonic synthesis of the geopotential models and the analysis of terrestrial data. We examine gravity models produced according to the latest approaches for gravity field recovery based on the principles of the Gravity field and steadystate Ocean Circulation Explorer (GOCE) and Gravity Recovery And Climate Experiment (GRACE) satellite missions. Furthermore, we evaluate the overall spectrum of the ultra-high degree combined gravity models EGM2008 and EIGEN-6C3stat. The terrestrial data consist of gravity and collocated GPS/levelling data in the overall Hellenic region. The software presented here implements the algorithm of spherical harmonic synthesis in a degree-wise cumulative sense. This approach may quantify the bandlimited performance of the individual models by monitoring the degree-wise computed functionals against the terrestrial data. The degree-wise analysis performed yields insight in the short-wavelengths of the Earth gravity field as these are expressed by the high degree harmonics.

  3. Off-level corrections for gravity meters

    NASA Astrophysics Data System (ADS)

    Niebauer, T. M.; Blitz, Thomas; Constantino, Andy

    2016-04-01

    Gravity meters must be aligned with the local gravity at any location on the surface of the earth in order to measure the full amplitude of the gravity vector. The gravitational force on the sensitive component of the gravity meter decreases by the cosine of the angle between the measurement axis and the local gravity vector. Most gravity meters incorporate two horizontal orthogonal levels to orient the gravity meter for a maximum gravity reading. In order to calculate a gravity correction it is often necessary to estimate the overall angular deviation between the gravity meter and the local gravity vector using two measured horizontal tilt meters. Typically this is done assuming that the two horizontal angles are independent and that the product of the cosines of the horizontal tilts is equivalent to the cosine of the overall deviation. These approximations, however, break down at large angles. This paper derives analytic formulae to transform angles measured by two orthogonal tilt meters into the vertical deviation of the third orthogonal axis. The equations can be used to calibrate the tilt sensors attached to the gravity meter or provide a correction for a gravity meter used in an off-of-level condition.

  4. High-precision gravity network to monitor temporal variations in gravity across Yucca Mountain, Nevada

    SciTech Connect

    Harris, R.N.; Ponce, D.A.

    1988-12-31

    Repeatable high-precision gravity surveys provide a method of monitoring temporal variations in the gravity field. Fluctuations in the gravity field may indicate water table changes, crustal deformation, or precursors to volcanism and earthquakes. This report describes a high-precision gravity loop which has been established across Yucca Mountain, Nevada in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) program. The purpose of this gravity loop is to monitor temporal variations in gravity across Yucca Mountain in an effort to interpret and predict the stability of the tectonic framework and changes in the subsurface density field. Studies of the tectonic framework which include volcanic hazard seismicity, and faulting studies are in progress. Repeat high-precision gravity surveys are less expensive and can be made more rapidly than a corresponding leveling survey. High-precision gravity surveys are capable of detecting elevation changes of 3 to 5 cm, and thus can be employed as an efficient tool for monitoring vertical crustal movements while supplementing or partially replacing leveling data. The Yucca Mountain gravity network has been tied to absolute gravity measurements established in southern Nevada. These ties provide an absolute datum for comparing repeat occupations of the gravity network, and provide a method of monitoring broad-scale changes in gravity. Absolute gravity measurements were also made at the bottom and top of the Charleston Peak calibration loop in southern Nevada. These absolute gravity measurements provide local control of calibrating gravity meters over the gravity ranges observed at Yucca Mountain. 13 refs., 7 figs., 3 tabs.

  5. Monitoring the influence of high-gravity brewing and fermentation temperature on flavour formation by analysis of gene expression levels in brewing yeast.

    PubMed

    Saerens, S M G; Verbelen, P J; Vanbeneden, N; Thevelein, J M; Delvaux, F R

    2008-10-01

    During fermentation, the yeast Saccharomyces cerevisiae produces a broad range of aroma-active substances, which are vital for the complex flavour of beer. In order to obtain insight into the influence of high-gravity brewing and fermentation temperature on flavour formation, we analysed flavour production and the expression level of ten genes (ADH1, BAP2, BAT1, BAT2, ILV5, ATF1, ATF2, IAH1, EHT1 and EEB1) during fermentation of a lager and an ale yeast. Higher initial wort gravity increased acetate ester production, while the influence of higher fermentation temperature on aroma compound production was rather limited. In addition, there is a good correlation between flavour production and the expression level of specific genes involved in the biosynthesis of aroma compounds. We conclude that yeasts with desired amounts of esters and higher alcohols, in accordance with specific consumer preferences, may be identified based on the expression level of flavour biosynthesis genes. Moreover, these results demonstrate that the initial wort density can determine the final concentration of important volatile aroma compounds, thereby allowing beneficial adaptation of the flavour of beer. PMID:18751696

  6. An Improved Platform Levelling System for Airborne Gravity Meters.

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2014-12-01

    Recent advances in sensor technology have enabled Lacoste and Romberg type relative gravity meters to improve in accuracy to the point where other non-sensor related sources of error serve to limit the overall accuracy of the system. One of these sources of error is derived from the inability of the platform, in which the sensor is mounted, to keep the sensor perfectly level during survey flight. Off level errors occur when the aircraft is unable to maintain straight and level flight along a survey line. The levelling platform of a typical Lacoste and Romberg type dynamic gravity meter utilizes a complex feedback loop involving both accelerometers and gyroscopes with an output connected to torque motors mounted to the platform to sense an off level situation and correct for it. The current system is limited by an inability of the platform to distinguish between an acceleration of the platform due to a change in heading, altitude or speed of the aircraft and a true change in the local gravity vertical. Both of these situations cause the platform to tilt in reponse however the aircraft acceleration creates an error in the gravity measurement. These off level errors can be corrected for to a limited degree depending on the algorithm used and the size and duration of the causal acceleration. High precision GPS now provides accurate real time position information which can be used to determine if an accleration is a real level change or due to an anomalous acceleration. The correct implementation of the GPS position can significantly improve the accuracy of the platform levelling including keeping the platform level during course reversals or drape flying during a survey. This can typically improve the quality of the gravity data before any processing corrections. The enhanced platform also reduces the time taken to stabilize the platform at the beginning of a survey line therefore improving the efficiency of the data collection. This paper discusses the method and results of tests of the new GPS aided platform system developed by Dynamic Gravity Systems

  7. Effects of wort gravity and nitrogen level on fermentation performance of brewer's yeast and the formation of flavor volatiles.

    PubMed

    Lei, Hongjie; Zhao, Haifeng; Yu, Zhimin; Zhao, Mouming

    2012-03-01

    Normal gravity wort and high gravity wort with different nitrogen levels were used to examine their effects on the fermentation performance of brewer's yeast and the formation of flavor volatiles. Results showed that both the wort gravity and nitrogen level had significant impacts on the growth rate, viability, flocculation, and gene expression of brewer's yeast and the levels of flavor volatiles. The sugar (glucose, maltose, and maltotriose) consumption rates and net cell growth decreased when high gravity worts were used, while these increased with increasing nitrogen level. Moreover, high gravity resulted in lower expression levels of ATF1, BAP2, BAT1, HSP12, and TDH, whereas the higher nitrogen level caused higher expression levels for these genes. Furthermore, the lower nitrogen level resulted in increases in the levels of higher alcohols and esters at high wort gravity. All these results demonstrated that yeast physiology and flavor balance during beer brewing were significantly affected by the wort gravity and nitrogen level. PMID:22281783

  8. Micro-Gal level gravity measurements with cold atom interferometry

    NASA Astrophysics Data System (ADS)

    Zhou, Min-Kang; Duan, Xiao-Chun; Chen, Le-Le; Luo, Qin; Xu, Yao-Yao; Hu, Zhong-Kun

    2015-05-01

    Developments of the micro-Gal level gravimeter based on atom interferometry are reviewed, and the recent progress and results of our group are also presented. Atom interferometric gravimeters have shown high resolution and accuracy for gravity measurements. This kind of quantum sensor has excited world-wide interest for both practical applications and fundamental research. Project supported by the National Natural Science Foundation of China (Grant Nos.41127002, 11204094, 11205064, and 11474115) and the National High Technology Research and Development Program of China (Grant No.2011AA060503).

  9. High-Resolution Gravity and Time-Varying Gravity Field Recovery using GRACE and CHAMP

    NASA Technical Reports Server (NTRS)

    Shum, C. K.

    2002-01-01

    This progress report summarizes the research work conducted under NASA's Solid Earth and Natural Hazards Program 1998 (SENH98) entitled High Resolution Gravity and Time Varying Gravity Field Recovery Using GRACE (Gravity Recovery and Climate Experiment) and CHAMP (Challenging Mini-satellite Package for Geophysical Research and Applications), which included a no-cost extension time period. The investigation has conducted pilot studies to use the simulated GRACE and CHAMP data and other in situ and space geodetic observable, satellite altimeter data, and ocean mass variation data to study the dynamic processes of the Earth which affect climate change. Results from this investigation include: (1) a new method to use the energy approach for expressing gravity mission data as in situ measurements with the possibility to enhance the spatial resolution of the gravity signal; (2) the method was tested using CHAMP and validated with the development of a mean gravity field model using CHAMP data, (3) elaborate simulation to quantify errors of tides and atmosphere and to recover hydrological and oceanic signals using GRACE, results show that there are significant aliasing effect and errors being amplified in the GRACE resonant geopotential and it is not trivial to remove these errors, and (4) quantification of oceanic and ice sheet mass changes in a geophysical constraint study to assess their contributions to global sea level change, while the results improved significant over the use of previous studies using only the SLR (Satellite Laser Ranging)-determined zonal gravity change data, the constraint could be further improved with additional information on mantle rheology, PGR (Post-Glacial Rebound) and ice loading history. A list of relevant presentations and publications is attached, along with a summary of the SENH investigation generated in 2000.

  10. The Gravity Model for High School Students

    ERIC Educational Resources Information Center

    Tribble, Paul; Mitchell, William A.

    1977-01-01

    The authors suggest ways in which the gravity model can be used in high school geography classes. Based on Newton's Law of Molecular Gravitation, the law states that gravitation is in direct ratio to mass and inverse ratio to distance. One activity for students involves determination of zones of influence of cities of various sizes. (Author/AV)

  11. Improved Source Parameter Constraints for Recent Large Undersea Earthquakes from High-degree GRACE Gravity and Gravity Gradient Change Measurements

    NASA Astrophysics Data System (ADS)

    Dai, C.; Shum, C. K.; Wang, R.; Guo, J.; Shang, K.; Tapley, B. D.; Wang, L.

    2014-12-01

    The north component of gravity and gravity gradient changes from the high degree (up to degree 96) data products of the Gravity Recovery And Climate Experiment (GRACE) are used to study the coseismic gravity change for five earthquakes over the last decade including the 2004 Sumatra-Andaman and 2005 Nias earthquakes, the 2010 Maule, Chile earthquake, the 2011 Tohoku earthquake, the 2012 Indian Ocean earthquakes, and the 2007 Bengkulu earthquake. We demonstrate the advantage of these components to reduce north-south stripes and preserve higher spatial resolution signal in GRACE Level 2 (L2) data, revealing gravity change up to -33 ?Gal for the 2004 Sumatra-Andaman and 2005 Nias earthquakes, which is by far the highest coseismic signal achievable by innovative GRACE data processing, and revealing the detectability of earthquakes as small as Mw 8.6 (e.g., the 2012 Indian Ocean earthquakes). The localized spectral analysis is applied as an efficient method to determine the practical spherical harmonic truncation degree leading to acceptable signal-to-noise ratio, and to evaluate the noise level for each component of gravity and gravity gradient change of the seismic deformations. For each of the earthquakes, the centroid moment tensor parameters, in particular the centroid location, depth, and slip rake angle are estimated via forward modeling inversions using the improved GRACE gravity and gravity gradient data.

  12. The gravity field of the level triaxial ellipsoid

    NASA Astrophysics Data System (ADS)

    Panou, Georgios; Delikaraoglou, Demitris

    2013-04-01

    Geodetic research has traditionally been motivated by the need to approximate closer and closer the physical reality. Several investigations have shown that the earth is approximated better by a triaxial ellipsoid rather than a biaxial one. Furthermore, non-spherical celestial bodies such as planets, physical satellites, asteroids and comets can be modeled by a triaxial ellipsoid. Also, the present day accuracy requirements and the modern computational capabilities push toward the study on the triaxial ellipsoid as a geometrical and a physical model in geodesy and related interdisciplinary sciences. From the viewpoint of its physical characteristics, it is assumed that the triaxial ellipsoid has mass and rotates with constant angular velocity. Also, this ellipsoid is a level (or equipotential) surface of its own gravity field. In this paper, the gravity field of the level triaxial ellipsoid is presented. An ellipsoidal coordinate system and the ellipsoidal harmonics are introduced. The gravitational potential is determined by solving an exterior Dirichlet's boundary-value problem. Hence, the gravity potential is completely and uniquely determined outside the triaxial ellipsoid. From the gravity potential the gravity vector is consequently obtained in the exterior space and on the surface of the level ellipsoid. The gravity field of the level biaxial ellipsoid is included as a degenerate case.

  13. Aircraft center of gravity and fuel level advisory system

    SciTech Connect

    Adelson, R.L.; Nusbaum, F.D. Jr.

    1986-11-11

    This patent describes an aircraft center of gravity and fuel level advisory system for fixed wing aircraft connected to the aircraft's fuel gauges and operated by one of the aircraft's personnel, the system comprising: a control panel processor unit connected to the aircraft's power source and fuel gauges. The processor unit includes a computer and memory for storing and calculating aircraft weight, center of gravity, fuel consumption and transfer, the weight and center of gravity shift of internal and external payload items as they are expended; a keyboard mounted on the processor unit and connected thereto, the keyboard having a power on/off switch, a fuel level switch, a load switch and a weight switch; and a remote display unit connected to the processor.

  14. Antarctic marine gravity field from high-density satellite altimetry

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.

    1992-01-01

    High-density (about 2-km profile spacing) Geosat/GM altimetry profiles were obtained for Antarctic waters (6-deg S to 72 deg S) and converted to vertical gravity gradient, using Laplace's equation to directly calculate gravity gradient from vertical deflection grids and Fourier analysis to construct gravity anomalies from two vertical deflection grids. The resultant gravity grids have resolution and accuracy comparable to shipboard gravity profiles. The obtained gravity maps display many interesting and previously uncharted features, such as a propagating rift wake and a large 'leaky transform' along the Pacific-Antarctic Rise.

  15. The role of new terrestrial gravity/GPS/levelling data, GRACE geopotential model and SRTM elevations on the earth gravity field modelling and its changes in Iran

    NASA Astrophysics Data System (ADS)

    Hatam Chavari, Yaghoub; Bayer, Roger; Djamour, Yahya; Vanicek, Petr

    2010-05-01

    In order to model the earth gravity field and its temporal variations, different gravity data with terrestrial, airborne and satellite gathered kinds are necessary. It is possible to recover by them the short, medium and long wavelengths of the gravity field respectively. Terrestrial gravity data, especially for the regions with highly variations, are useful for different purposes, i.e. to estimate the actual gravity range in the country, to extend the gravity calibration line, to study the isostasy status (Aboghasem et al., EGU10), to modify the numerical density models, to ameliorate the local geoid models, to prepare a background for geodynamical researches, and so on. The Multi-purpose Physical Geodesy and Geodynamics Network of Iran has recently established over Iran with 700 stations of 30' by 30' distribution (MPGGNI05, Hatam et al., EGU08). About 2000 precise relative gravity measurements gathered between the neighbour stations are prepared the possibility to compute the accurate, confident and homogeneous gravity values for the mentioned network. The MPGGNI is connected to the new 24-stations established national absolute gravity base network of Iran (NGBI09, Hatam et al., EGU09) to unify the reference system and to strengthen the accuracy and confident over the country. All 6 used relative gravimeters were regularly calibrated by the recently established tele cabin/ land national gravity calibration line (TC/L NGCLI, Hatam et al., EGU07). In addition, precise levelling measurements have tied the MPGGNI stations and have connected the new network to the existed national precise levelling network of Iran. Also, precise GPS measurements have been done at each station of MPGGNI with 24 hours duration. The MPGGNI can be understood typically as a precise gravity and GPS/Levelling network, and by repeating it, it is possible to model the changes of different components of the gravity field. In order to improve the precision of old gravity data, each station of MPGGNI was tied to the existed levelling bench marks by relative gravity measurements. The already existed gravity data in Iran are about 22,000 points which half of them are at precise levelling stations. In order to choose an optimum geopotential model for Iran, to compute the long wavelengths part of the gravity field, a study has been followed based on different satellite only and combined global models, e.g., EIGEN-GRACE02S and EGM08, up to maximum degree and order of 360/360. The SRTM and GTOPO30 elevation data have used for the evaluation of topographical effects for near and far zones respectively. A new built density model with lateral variations, based on 1:250,000 geological maps (Cheraghi, EGU07), has used together with the mentined elevation models to ameliorate the results. The GRAVSOFT and SHGEO softwares are used for the computation of earth gravity field over Iran, typically the gravimetric geoid. A comparison was made between the gravimetric geoid and GPS/levelling points. An adjustment was finally made between the two mentioned kind models. To improve the gravity field model locally in the highest mountain of Iran, (Damavand 5610 m, Hatam et al., EGU09), the data of a profile containing gravity, gps, and trigonometric levelling from down to the summit have used. Several absolute gravity stations were measured repeatedly each year since 2000. A study is made to understand the possible correlations between the gravity changes, underground water level changes, repeated precise levelling measurements, permanent GPS stations and geoidal suface varations.

  16. Effects of gravity level on bubble formation and rise in low-viscosity liquids

    NASA Astrophysics Data System (ADS)

    Suñol, Francesc; González-Cinca, Ricard

    2015-05-01

    We present an experimental analysis of the effects of gravity level on the formation and rise dynamics of bubbles. Experiments were carried out with millimeter-diameter bubbles in the hypergravity environment provided by the large-diameter centrifuge of the European Space Agency. Bubble detachment from a nozzle is determined by buoyancy and surface tension forces regardless of the gravity level. Immediately after detachment, bubble trajectory is deviated by the Coriolis force. Subsequent bubble rise is dominated by inertial forces and follows a zig-zag trajectory with amplitude and frequency dependent on the gravity level. Vorticity production is enhanced as gravity increases, which destabilizes the flow and therefore the bubble path.

  17. A high frequency resonance gravity gradiometer

    SciTech Connect

    Bagaev, S. N.; Kvashnin, N. L.; Skvortsov, M. N.; Bezrukov, L. B.; Krysanov, V. A.; Oreshkin, S. I.; Motylev, A. M.; Popov, S. M.; Samoilenko, A. A.; Yudin, I. S.; Rudenko, V. N.

    2014-06-15

    A new setup OGRANthe large scale opto-acoustical gravitational detector is described. As distinguished from known gravitational bar detectors it uses the optical interferometrical readout for registering weak variations of gravity gradient at the kilohetz frequency region. At room temperature, its sensitivity is limited only by the bar Brownian noise at the bandwidth close to 100 Hz. It is destined for a search for rare eventsgravitational pulses coincident with signals of neutrino scintillator (BUST) in the deep underground of Baksan Neutrino Observatory of INR RAS.

  18. A high frequency resonance gravity gradiometer.

    PubMed

    Bagaev, S N; Bezrukov, L B; Kvashnin, N L; Krysanov, V A; Oreshkin, S I; Motylev, A M; Popov, S M; Rudenko, V N; Samoilenko, A A; Skvortsov, M N; Yudin, I S

    2014-06-01

    A new setup OGRAN--the large scale opto-acoustical gravitational detector is described. As distinguished from known gravitational bar detectors it uses the optical interferometrical readout for registering weak variations of gravity gradient at the kilohetz frequency region. At room temperature, its sensitivity is limited only by the bar Brownian noise at the bandwidth close to 100 Hz. It is destined for a search for rare events--gravitational pulses coincident with signals of neutrino scintillator (BUST) in the deep underground of Baksan Neutrino Observatory of INR RAS. PMID:24985859

  19. Superalloy microstructural variations induced by gravity level during directional solidification

    NASA Technical Reports Server (NTRS)

    Johnston, M. H.; Curreri, P. A.; Parr, R. A.; Alter, W. S.

    1985-01-01

    The Ni-base superalloy MAR-M246 (Hf) was directionally solidified during low gravity maneuvers aboard a NASA KC-135 aircraft. Gravity force variations during this process yielded a concomitant variation in microstructure and microsegregation. Secondary dendrite arm spacings are noted to be larger in the low-g portion; this, in turn, decreases the extent of interdendritic segregation. The amount of Hf in both the carbides and interdendritic eutectic increases as the gravity force diminishes. Fewer carbides are present in the low-g regions.

  20. Nucleate pool boiling: High gravity to reduced gravity; liquid metals to cryogens

    NASA Technical Reports Server (NTRS)

    Merte, Herman, Jr.

    1988-01-01

    Requirements for the proper functioning of equipment and personnel in reduced gravity associated with space platforms and future space station modules introduce unique problems in temperature control; power generation; energy dissipation; the storage, transfer, control and conditioning of fluids; and liquid-vapor separation. The phase change of boiling is significant in all of these. Although both pool and flow boiling would be involved, research results to date include only pool boiling because buoyancy effects are maximized for this case. The effective application of forced convection boiling heat transfer in the microgravity of space will require a well grounded and cogent understanding of the mechanisms involved. Experimental results are presented for pool boiling from a single geometrical configuration, a flat surface, covering a wide range of body forces from a/g = 20 to 1 to a/g = 0 to -1 for a cryogenic liquid, and from a/g = 20 to 1 for water and a liquid metal. Similarities in behavior are noted for these three fluids at the higher gravity levels, and may reasonably be expected to continue at reduced gravity levels.

  1. Transformation between gravimetric and GPS/leveling derived geoids using additional gravity information

    NASA Astrophysics Data System (ADS)

    Grebenitcharsky, R.; Rangelova, E.; Sideris, M. G.

    2003-04-01

    The transformation between gravimetric and GPS/leveling derived geoids using additional gravity data for the covariance function of geoid undulation differences has been investigated in a test area in Eastern Canada. A corrector surface model, which accounts for datum inconsistencies, long-wavelength geoid errors and vertical network distortions, has been constructed using least-squares collocation (LSC). The usual procedure assumes that the local covariance function of geoid undulation differences has been determined from the residuals of GPS/leveling geoid heights with respect to the gravimetric geoid, after a preliminary elimination of all systematic effects. If additional gravity data are available, the covariance function of geoid undulation residuals can be separately determined in the following steps: (1) transformation of GPS/leveling derived geoid heights into gravity anomalies; (2) substracting the measured gravity anomalies from the transformed anomalies; (3) determination of the parameters of the local gravity covariance function of the gravity anomaly differences; and (4) constructing a new analytical covariance function for geoid undulation differences from the covariance function of the gravity anomaly differences. using the parameters derived in previous step. The main advantages of the proposed method are the greater number of gravity data available and the fact that gravity data themselves do not contain some systematic effects typical for geoid heights. Analytical covariance models, commonly used in local gravity field modeling, have been used to compare the proposed transformation procedure with the standard method for corrector surface determination using LSC. Furthermore, in view of the small area, the systematic component of the corrector surface has been modeled using linear polynomial regression. GPS/leveling points which are different from the points used for corrector surface determination have been used as external control points. Conclusions regarding the advantages of proposed approach have been drawn.

  2. Effects of gravity level on bubble formation and rise in low-viscosity liquids.

    PubMed

    Suñol, Francesc; González-Cinca, Ricard

    2015-05-01

    We present an experimental analysis of the effects of gravity level on the formation and rise dynamics of bubbles. Experiments were carried out with millimeter-diameter bubbles in the hypergravity environment provided by the large-diameter centrifuge of the European Space Agency. Bubble detachment from a nozzle is determined by buoyancy and surface tension forces regardless of the gravity level. Immediately after detachment, bubble trajectory is deviated by the Coriolis force. Subsequent bubble rise is dominated by inertial forces and follows a zig-zag trajectory with amplitude and frequency dependent on the gravity level. Vorticity production is enhanced as gravity increases, which destabilizes the flow and therefore the bubble path. PMID:26066251

  3. Investigating High Field Gravity using Astrophysical Techniques

    SciTech Connect

    Bloom, Elliott D.; /SLAC

    2008-02-01

    The purpose of these lectures is to introduce particle physicists to astrophysical techniques. These techniques can help us understand certain phenomena important to particle physics that are currently impossible to address using standard particle physics experimental techniques. As the subject matter is vast, compromises are necessary in order to convey the central ideas to the reader. Many general references are included for those who want to learn more. The paragraphs below elaborate on the structure of these lectures. I hope this discussion will clarify my motivation and make the lectures easier to follow. The lectures begin with a brief review of more theoretical ideas. First, elements of general relativity are reviewed, concentrating on those aspects that are needed to understand compact stellar objects (white dwarf stars, neutron stars, and black holes). I then review the equations of state of these objects, concentrating on the simplest standard models from astrophysics. After these mathematical preliminaries, Sec. 2(c) discusses 'The End State of Stars'. Most of this section also uses the simplest standard models. However, as these lectures are for particle physicists, I also discuss some of the more recent approaches to the equation of state of very dense compact objects. These particle-physics-motivated equations of state can dramatically change how we view the formation of black holes. Section 3 focuses on the properties of the objects that we want to characterize and measure. X-ray binary systems and Active Galactic Nuclei (AGN) are stressed because the lectures center on understanding very dense stellar objects, black hole candidates (BHCs), and their accompanying high gravitational fields. The use of x-ray timing and gamma-ray experiments is also introduced in this section. Sections 4 and 5 review information from x-ray and gamma-ray experiments. These sections also discuss the current state of the art in x-ray and gamma-ray satellite experiments and plans for future experiments.

  4. Gravity and cyclic GMP levels in melanocytic cells.

    PubMed

    Ivanova, Krassimira; Zadeh, Nahid Hamidi; Block, Ingrid; Das, Pranab K; Gerzer, Rupert

    2002-07-01

    Guanosine 3',5'-cyclic monophosphate (cyclic GMP) is a major second messenger molecule, that is believed to play a role in various physiological and pathophysiological processes. Here we report that hypergravity induces differential effects on cyclic GMP turnover in melanocytic cells. Nonmetastatic melanoma cells responded to long-time exposure (24 h) of hypergravity (up to 5 x g) with decrease in intracellular cyclic GMP accumulation in the presence of an universal inhibitor of phosphodiesterases (IBMX), whereas the extracellular cyclic GMP increase. In contrast, there were no changes in cyclic GMP turnover in metastatic melanocytes. The expression of the guanylyl cyclases appeared to be not affected. These results suggest that cyclic GMP signaling may be involved in adaptation of human melanocytes to altered gravity conditions. PMID:15002576

  5. Effect of additives on the properties of polyaniline nanofibers prepared by high gravity chemical oxidative polymerization.

    PubMed

    Zhao, Yibo; Arowo, Moses; Wu, Wei; Chen, Jianfeng

    2015-05-12

    Polyaniline (PANI) nanofibers with improved properties were prepared by high gravity chemical oxidative polymerization in a rotating packed bed with the assistance of p-aminodiphenylamine (AD) and p-phenylenediamine (AP). The effects of reactor type, additive dosage, reaction temperature, and high-gravity level on the properties of products were investigated in detail. Three conclusions were made: (1) a small amount of additive can significantly improve some properties of the nanofibers such as uniformity, specific surface area, and specific capacitance; (2) in order to obtain high-quality nanofibers, the high-gravity level should coordinate with the reaction rate; (3) the molecular weight and conductivity of PANI decrease with the increase of additive dosage. The products have larger specific surface areas of up to 73.9 and 68.4 m(2)/g and consequently improved specific capacitance of up to 527.5 and 552 F/g for the PANI nanofibers prepared with AD and AP, respectively. However, the specific surface area and specific capacitance of pure PANI are only 49.1 m(2)/g and 333.3 F/g, respectively. This research provides a simple, reliable, and scalable method to produce PANI nanofibers of high performances. PMID:25879305

  6. High-Resolution Infra-Red Imaging Studies of Mesospheric Gravity Waves (Invited)

    NASA Astrophysics Data System (ADS)

    Taylor, M. J.; Pautet, P.; Zhao, Y.; Pendleton, W. R.; Yuan, T.; Esplin, R.; McLain, D.; Fritts, D. C.; Stober, G.

    2013-12-01

    This presentation highlights new research capabilities and recent results focusing on polar latitudes using two new infra-red imaging systems operating at the ALOMAR Arctic Observatory, Norway and at the Amundsen-Scott Base, South Pole, Antarctica. The Advanced Mesospheric Temperature Mapper (AMTM) is a novel infrared digital imaging system that measures selected emission lines in the mesospheric OH (3,1) band (at ~1.5?m) to create high-quality intensity and temperature maps of a broad spectrum of mesospheric gravity waves (with periods ranging from several minutes to many hours). The data are obtained with an unprecedented spatial (~0.5 km) and temporal (typically 30 sec) resolution over a large 120 field of view enabling detailed measurements of wave propagation and dissipation at the ~87 km level, even in the presence of strong aurora. Several new results will be presented and discussed, including high-resolution imaging studies of gravity wave breaking, first evidence of gravity wave 'self-acceleration' and new coordinated lidar, radar and AMTM measurements of gravity wave propagation and ducting at mid-latitudes.

  7. Evaporation dynamics of ethanol drops under terrestrial and reduced gravity levels

    NASA Astrophysics Data System (ADS)

    Carle, Florian; Sobac, Benjamin; Brutin, David

    2012-11-01

    This experimental study, performed under microgravity conditions, focuses on the evaporation dynamics of ethanol drops and the formation and behaviour of the hydrothermal waves (HTWs) that spontaneously develop on the drops' surfaces. The aim of this study is to compare our results to a similar study performed under normal gravity conditions to confirm the purely thermocapillary origin of these instabilities. Under normal gravity conditions, a temperature gradient develops during the evaporation from the apex of the drop and the contact line, resulting in a gradient of surface tension, generating instabilities. HTWs flow radially around the apex where most of the evaporation takes place. In microgravity, the temperature gradient isn't as much defined as the one in normal gravity, but the apex maintains a temperature below the one of triple line. For different substrate temperatures and different levels of gravity, the HTWs follow a power law decay of the number of instabilities. Microgravity experiments show the same power law evolution. A scaling law succeed to predict with a good agreement the number of instabilities that form, regardless of the drop diameters, the substrate temperatures and the gravity levels. We would like to thank the ``Centre National d'tudes Spatiales'' for their financial support for parabolic flights campaigns.

  8. High energy scattering in QCD and in quantum gravity

    NASA Astrophysics Data System (ADS)

    Lipatov, L. N.

    2014-06-01

    The theory of the high energy scattering in QCD is based on the BFKL equation for the Pomeron wave function and on its generalization for composite multi-gluon states in the crossing channel. At a large number of colors the equations for the gluon composite states have remarkable mathematical properties including their Mbius invariance, holomorphic separability, duality symmetry and integrability. High energy QCD interactions local in the particle rapidities are formulated in the form of the gauge invariant effective action. In the maximally extended N = 4 super-symmetry the Pomeron turns out to be dual to the reggeized graviton in the 10-dimensional anti-de-Sitter space. As a result, the Gribov calculus for the Pomeron interactions should be reformulated here as a generally covariant effective field theory for the reggeized gravitons. We construct the corresponding effective action, which gives a possibility to calculate their trajectory and couplings. The graviton trajectory in the leading order contains an ultraviolet divergency meaning the presence of the double-logarithmic (DL) terms. We sum the DL contributions in all orders of the perturbation theory in the Einstein-Hilbert gravity and in its super-symmetric generalizations. In the N = 8 super gravity the ratio of the scattering amplitude in the DL approximation to the Born expression tends to zero at large energies.

  9. High pressure droplet burning experiments in reduced gravity

    NASA Technical Reports Server (NTRS)

    Chauveau, Christian; Goekalp, Iskender

    1995-01-01

    A parametric investigation of single droplet gasification regimes is helpful in providing the necessary physical ideas for sub-grid models used in spray combustion numerical prediction codes. A research program has been initiated at the LCSR to explore the vaporization regimes of single and interacting hydrocarbon and liquid oxygen droplets under high pressure conditions. This paper summarizes the status of the LCSR program on the high pressure burning of single fuel droplets; recent results obtained under normal and reduced gravity conditions with suspended droplets are presented. In the work described here, parabolic flights of the CNES Caravelle is used to create a reduced gravity environment of the order of 10(exp -2) g(sub O). For all the droplet burning experiments reported here, the suspended droplet initial diameters are scattered around 1.5 mm; and the ambient air temperature is 300 K. The ambient pressure is varied between 0.1 MPa and 12 MPa. Four fuels are investigated: methanol (Pc = 7.9 MPa), n-heptane (Pc = 2.74 MPa), n-hexane (Pc = 3.01 MPa) and n-octane (Pc = 2.48 MPa).

  10. Harmonic Analysis of GPS/Leveling for Validation of GRACE-/GOCE-Based Gravity Models.

    NASA Astrophysics Data System (ADS)

    Holmes, S. A.; Li, X.; Roman, D. R.

    2012-12-01

    Satellite gravity models from the GRACE and GOCE missions provide much of the long-wavelength structure of all modern gravimetric geoid models. At the same time, such gravimetric geoid models are tested and verified through comparisons with independent data, such as GPS/Leveling [GPSL] data. As part of its efforts to move the United States and its territories to a geoid-based vertical height system by 2020, the National Geodetic Survey will be working with both satellite gravity, and GPSL information, to compute the most accurate gravimetric geoid model from the available data. In this study, we seek to achieve something of a cross-validation between these two complimentary data types. Specifically, we compare various GOCE-/GRACE-based gravity models with latest NGS GPSL data over the Contiguous United States [CONUS]. EGM2008 is included in these comparisons. For meaningful 'degree (n) -wise' analysis over non-global (regional) extent, one approach which has proven useful is to first create a 'hybrid' Earth Gravitational Model [EGM] which is supported solely by the NGS GPSL inside CONUS, and by an average of the GOCE-/GRACE-based gravity models everywhere else. Careful treatment of this hybrid EGM yields, inside CONUS, degree-wise discrepancies between the GPSL and the various gravity models. These degree-wise discrepancies, in turn, provide insight into the regional error spectrum for each of the gravity models tested, thereby informing the final combination of satellite gravity with terrestrial- and airborne- gravimetry to yield an optimal gravimetric geoid model. Early results from this work are presented. Statewide biases and tilts in the NGS GPSL are also considered and discussed.

  11. Influence of gravity level and interfacial energies on dispersion-forming tendencies in hypermonotectic Cu-Pb-Al alloys

    NASA Technical Reports Server (NTRS)

    Andrews, J. B.; Curreri, P. A.; Sandlin, A. C.

    1988-01-01

    Results on the nondirectional solidification of several hypermonotectic Cu-Pb-Al alloys were obtained aboard NASA's KC-135 zero-gravity aircraft in order to determine the influence of interfacial energies and gravity levels on dispersion-forming tendencies. The Al content was systematially varied in the alloys. The dispersion-forming ability is correlated with gravity level during solidification, the interfacial energy between the immiscible phases, and the tendency for the minority immiscible phase to wet the walls of the crucible.

  12. High potassium level

    MedlinePLUS

    ... disease Take medications to treat heart disease or high blood pressure Use salt substitutes ... if you are asked to eat a low-salt diet Your doctor may make the ... and high blood pressure Take a certain type of water pill to ...

  13. Completing Lorentz violating massive gravity at high energies

    NASA Astrophysics Data System (ADS)

    Blas, D.; Sibiryakov, S.

    2015-03-01

    Theories with massive gravitons are interesting for a variety of physical applications, ranging from cosmological phenomena to holographic modeling of condensed matter systems. To date, they have been formulated as effective field theories with a cutoff proportional to a positive power of the graviton mass m g and much smaller than that of the massless theory ( M P ? 1019 GeV in the case of general relativity). In this paper, we present an ultraviolet completion for massive gravity valid up to a high energy scale independent of the graviton mass. The construction is based on the existence of a preferred time foliation combined with spontaneous condensation of vector fields. The perturbations of these fields are massive and below their mass, the theory reduces to a model of Lorentz violating massive gravity. The latter theory possesses instantaneous modes whose consistent quantization we discuss in detail. We briefly study some modifications to gravitational phenomenology at low-energies. The homogeneous cosmological solutions are the same as in the standard cosmology. The gravitational potential of point sources agrees with the Newtonian one at distances small with respect to m {/g -1}. Interestingly, it becomes repulsive at larger distances.

  14. Regional lunar gravity anomaly recovery with the GRAIL Level-1b data, and pin-point crustal density estimation with the GRAIL Level-2 and LRO topography data

    NASA Astrophysics Data System (ADS)

    Hashimoto, M.; Heki, K.

    2014-12-01

    We report the lunar gravity anomaly recovery using the GRAIL Level-1b and Level-2 data, downloaded from the PDS Geoscience Node at the Washington University. First, we used the GNV1b (satellite position data) and KBR1b (inter-satellite ranging data) files of the Level-1b data to estimate the surface mass distribution on the Moon following the method of Sugano and Heki (EPS 2004; GRL 2005). We confirmed that we could recover the gravity anomalies similar to the Level-2 data with spatial resolution of ~0.8 degrees using low altitude portions of the data. Next, we downloaded the GRAIL Level-2 data set (spherical harmonics with degree/order complete to 660) together with the topography data by LRO laser altimetry, and tried to estimate the pin-point surface crustal density. First, we selected a certain square as large as ~60 km, and compared the gravity and topography values at grid points within the square. They are roughly proportional, and the slope provides information on the density of the material making the topography. This method, however, causes apparent positive correlation between density and average topographic height of about 0.2 g/cm^3/km. We (wrongly) assume that the mass anomalies lie on the reference surface. Then, the mass above (below) the reference surface is interpreted heavier/lighter than its real density. We performed a-posteriori correction of the altitude-dependent errors in the estimated density. We finally focus on a few positive gravity anomalies on the nearside (such as those close to the Copernicus crater) that are not associated with any topographic high. We will try to constrain the subsurface structure of the dense material responsible for the anomaly using both Level-1b and -2 data.

  15. Inversion of multi-level gravity data to improve lithospheric modelling - A case study for the North Atlantic region

    NASA Astrophysics Data System (ADS)

    Haase, Claudia; Bouman, Johannes; Ebbing, Jörg; Gradmann, Sofie; Lieb, Verena

    2014-05-01

    Modelling of the structure of the lithosphere is often affected by uncertainties in the sub-lithospheric mantle structure. For example, in the North Atlantic region both the gravity field and geoid are strongly affected by a regional component, which reflects the presence of density changes associated with the Iceland plume and the thermal structure of the upper mantle. Typically, the ultra-long wavelengths are therefore omitted in density modelling, but with a high degree of uncertainties of which wavelength to ignore. Satellite gravity gradient data are less affected by such a regional trend, and are mainly sensitive to intra-lithospheric sources. Due to their orbit height they are on the other hand little sensitive to near-surface structures. This makes them a useful addition to optimize model parameters and to increase confidence in the modelled structures. In addition, the isostatic state of the lithosphere can be evaluated to verify the model. For the North Atlantic region different crustal thickness compilations exist, which we can evaluate with the use of multi-level data. Such data sets are based on compilation of previous studies and/or interpolation between seismic profiles. For example in areas where no seismic profile exists, the uncertainty of such compilations can be up to 8 km. The combined use of gravity field and satellite gradients helps to evaluate these seismic compilations and to optimize the compilations within their error bounds. Furthermore, the oceanic crust and mantle have densities that are strongly temperature-dependent and vary with distance from the spreading ridge. This is a challenge for conventional gravity modelling, but we show how the non-vertical gravity tensor components can be used to estimate the density contrast between the lower crust and upper mantle.

  16. Paleozoic carbonate gravity-flow deposits, and relationships to changes of relative sea level, Southernmost Appalachians

    SciTech Connect

    Gilbert, O.E. Jr.

    1988-01-01

    The Jumbo Dolomite, deposited during a sea level fall at the end of the Early Ordovician, consists of lenticular carbonate masses embedded in the Mount Zion Formation, basinal shales deposited seaward of a Cambrian-Early Ordovician carbonate shelf. Stacked gravity-flow deposits include: (1) early massive debris-flow beds, with allogenic carbonate, chert, and sandstone clasts in a micritic matrix; (2) thick to massive debris-flow beds, with authigenic clasts in an argillaceous micritic matrix; and (3) late, fine-grained carbonate turbidites with partial Bouma sequences. Interbedded basinal shales (Bouma E) are more numerous in the upper part of this third unit. Gravity-flow deposits in the Athens (Middle Ordovician) and Floyd (mid-Mississippian) Shales were deposited during sea level rises. Argillaceous micrite turbidities in the Athens were derived from shallower bathymetric levels of a carbonate ramp. Gravity-flow deposits in the Floyd are individual tabular debris flows of skeletal debris and authigenic shale clasts in a micritic argillaceous matrix. Discrete gravity-flow beds deposited during sea level rises may be attributed to platform margin collapses. Stacking of flow deposits in the Jumbo indicates point-sourced flows localized by channels. The succession in the Jumbo represents stages in the fall, stabilization, and rise of sea level relative to the shelf; unit 1 represents early exposure and erosion of the shelf, and units 2 and 3 indicate the cessation of coarse debris input as a low-relief subaerial surface developed and sea level stabilized. Interbedded shales near the top of unit 3 represent sediment starvation associated with the subsequent rise of relative sea level.

  17. How unimodular gravity theories differ from general relativity at quantum level

    NASA Astrophysics Data System (ADS)

    Bufalo, R.; Oksanen, M.; Tureanu, A.

    2015-10-01

    We investigate path integral quantization of two versions of unimodular gravity. First a fully diffeomorphism-invariant theory is analyzed, which does not include a unimodular condition on the metric, while still being equivalent to other unimodular gravity theories at the classical level. The path integral has the same form as in general relativity (GR), except that the cosmological constant is an unspecified value of a variable, and it thus is unrelated to any coupling constant. When the state of the universe is a superposition of vacuum states, the path integral is extended to include an integral over the cosmological constant. Second, we analyze the standard unimodular theory of gravity, where the metric determinant is fixed by a constraint. Its path integral differs from the one of GR in two ways: the metric of spacetime satisfies the unimodular condition only in average over space, and both the Hamiltonian constraint and the associated gauge condition have zero average over space. Finally, the canonical relation between the given unimodular theories of gravity is established.

  18. Regulation by gravity of the transcript levels of MAP65 in azuki bean epicotyls

    NASA Astrophysics Data System (ADS)

    Soga, Kouichi; Hoson, Takayuki; Wakabayashi, Kazuyuki; Kotake, Toshihisa

    2012-07-01

    Development of a short and thick body by reorientation of cortical microtubules is required for the resistance of plants to the gravitational force. The 65 kDa microtubule-associated protein (MAP65) has microtubule bundling activity and is involved in the reorientation of cortical microtubules. Here, we investigated the relation between the orientation of cortical microtubules and the transcript levels of VaMAP65-1 under centrifugal hypergravity conditions in azuki bean epicotyls. The percentage of cells with transverse microtubules was decreased, while that with longitudinal microtubules was increased, in proportion to the logarithm of the magnitude of gravity. The orientation of microtubules was restored to the original direction after removal of the hypergravity stimulus. The transcript level of VaMAP65-1 was down-regulated in proportion to the logarithm of the magnitude of gravity (R=-0.99). By removal of hypergravity stimulus, expression of VaMAP65-1 was increased to control levels. Strong correlations were observed between the percentage of cells with longitudinal or transverse microtubules and the transcript levels of VaMAP65-1 (R=-0.93, 0.91). These results suggest that down-regulation of VaMAP65-1 expression is involved in the regulation by gravity of the orientation of cortical microtubules in azuki bean epicotyls. Lanthanum and gadolinium ions, potential blockers of mechanosensitive calcium ion-permeable channels (mechanoreceptors), nullified the down-regulation of expression of VaMAP65-1 gene, suggesting that mechanoreceptors are responsible for regulation by gravity of VaMAP65-1 expression.

  19. On the benefit of next-generation gravity missions for sea level and ocean mass applications

    NASA Astrophysics Data System (ADS)

    Kusche, J.; Lcher, A.; Rietbroek, R.; Eicker, A.; Flechtner, F.; Raimondo, J.-C.; Fenoglio-Marc, L.; Schrter, J.

    2012-04-01

    Today, the analysis of the Earth's time-variable gravity field plays a key role in Earth system research. The GRACE observables provide an almost direct measurement of the mass that is redistributed at or near the surface of the planet. Yet, important questions such as closing the sea level budget from GRACE, altimetry and steric data still pose a challenge, even after 9 years of GRACE. Promising approaches have been developed that combine multisensor data and/or model output, e.g. to estimate ocean warming/cooling, calibrate hydrological models or to improve geo-centre motion estimates. However, in the view of the authors, the biggest challenge in climate applications such as sea level studies is the problem of signal separation. This problem involves separating signal and noise stemming from the measurement systems and/or background modelling, as well as separating mass flux patterns originating from different or the same compartments of the Earth system (the leakage problem in ice sheet mass balance from GRACE, sea level rise partitioning, teleconnections in the hydrological cycle, trends in continental hydrology vs. GIA). Here we will first review the state of the art in addressing the signal separation problem after 10 years of GRACE. Then, we will discuss the potential of a number of candidate schemes for future gravity missions that were investigated in the recent ESA-funded Next Generation Gravity Mission (NG2) study.

  20. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    The use is studied of tether systems to improve the lowest possible steady gravity level on the Space Station. Particular emphasis is placed by the microgravity community on the achievement of high quality microgravity conditions. The tether capability is explored for active control of the center of gravity and the analysis of possible tethered configurations.

  1. Probing Gravity in the High-Redshift Universe with HETDEX

    NASA Astrophysics Data System (ADS)

    Malz, A. I.; Shandera, S.

    2014-01-01

    The addition of dark matter and dark energy to general relativity is degenerate with a modification of the dependence of curvature on the stress-energy tensor in the absence of exotic sources of matter and energy; it is thus valuable to explore the latter as a potential improvement over the former. Though it is inherently difficult to distinguish existing evidence for the general relativity paradigm from that of its more promising alternatives, such theories are associated with different histories for the largely unexplored growth of structure. Zhang, et al. (2007) have enabled discrimination of these possibilities via a new observable parameter EG and have predicted the efficacy of several future astronomical surveys to determine its value. In this work, we examine the ability of the Hobby Eberly Telescope Dark Energy Experiment (HETDEX) to contribute to calculations of this indicator of gravity at the highest redshifts (1.9 < z < 3.5). We show that a prerequisite of such a measurement is a deeper understanding of the nature of Lyman-? emitting galaxies (LAEs). If HETDEX can constrain the statistical properties of the typical LAE velocity dispersion, then it will not be necessary to wait for the (as yet unplanned) next generation of high-resolution spectrographs to obtain a test of general relativity in the high-redshift universe.

  2. Effects of Varying Gravity Levels in Parabolic Flight on the Size-Mass Illusion

    PubMed Central

    Clment, Gilles

    2014-01-01

    When an observer lifts two objects with the same weight but different sizes, the smaller object is consistently reported to feel heavier than the larger object even after repeated trials. Here we explored the effect of reduced and increased gravity on this perceptual size-mass illusion. Experiments were performed on board the CNES Airbus A300 Zero-G during parabolic flights eliciting repeated exposures to short periods of zero g, 0.16 g, 0.38 g, one g, and 1.8 g. Subjects were asked to assess perceived heaviness by actively oscillating objects with various sizes and masses. The results showed that a perceptual size-mass illusion was clearly present at all gravity levels. During the oscillations, the peak arm acceleration varied as a function of the gravity level, irrespective of the mass and size of the objects. In other words we did not observe a sensorimotor size-mass illusion. These findings confirm dissociation between the sensorimotor and perceptual systems for determining object mass. In addition, they suggest that astronauts on the Moon or Mars with the eyes closed will be able to accurately determine the relative difference in mass between objects. PMID:24901519

  3. Effects of varying gravity levels in parabolic flight on the size-mass illusion.

    PubMed

    Clment, Gilles

    2014-01-01

    When an observer lifts two objects with the same weight but different sizes, the smaller object is consistently reported to feel heavier than the larger object even after repeated trials. Here we explored the effect of reduced and increased gravity on this perceptual size-mass illusion. Experiments were performed on board the CNES Airbus A300 Zero-G during parabolic flights eliciting repeated exposures to short periods of zero g, 0.16 g, 0.38 g, one g, and 1.8 g. Subjects were asked to assess perceived heaviness by actively oscillating objects with various sizes and masses. The results showed that a perceptual size-mass illusion was clearly present at all gravity levels. During the oscillations, the peak arm acceleration varied as a function of the gravity level, irrespective of the mass and size of the objects. In other words we did not observe a sensorimotor size-mass illusion. These findings confirm dissociation between the sensorimotor and perceptual systems for determining object mass. In addition, they suggest that astronauts on the Moon or Mars with the eyes closed will be able to accurately determine the relative difference in mass between objects. PMID:24901519

  4. Introducing a high gravity field to enhance infiltration of small molecules into polyelectrolyte multilayers.

    PubMed

    Liu, Xiaolin; Zhao, Kun; Jiang, Chao; Wang, Yue; Shao, Lei; Zhang, Yajun; Shi, Feng

    2015-07-28

    Loading functional small molecules into nano-thin films is fundamental to various research fields such as membrane separation, molecular imprinting, interfacial reaction, drug delivery etc. Currently, a general demand for enhancing the loading rate without affecting the film structures exists in most infiltration phenomena. To handle this issue, we have introduced a process intensification method of a high gravity technique, which is a versatile energy form of mechanical field well-established in industry, into the investigations on diffusion/infiltration at the molecular level. By taking a polyelectrolyte multilayer as a model thin film and a photo-reactive molecule, 4,4'-diazostilbene-2,2'-disulfonic acid disodium salt (DAS), as a model small functional molecule, we have demonstrated remarkably accelerated adsorption/infiltration of DAS into a poly(allylamine hydrochloride) (PAH)/poly(acrylic acid) (PAA) multilayer by as high as 20-fold; meanwhile, both the film property of the multilayer and photoresponsive-crosslinking function of DAS were not disturbed. Furthermore, the infiltration of DAS and the surface morphology of the multilayer could be tuned based on their high dependence on the intensity of the high gravity field regarding different rotating speeds. The mechanism of the accelerated adsorption/infiltration under the high gravity field was interpreted by the increased turbulence of the diffusing layer with the thinned laminar boundary layer and the stepwise delivery of the local concentration gradient from the solution to the interior of the multilayer. The introduction of mechanical field provides a simple and versatile strategy to address the paradox of the contradictory loading amount and loading rate, and thus to promote applications of various membrane processes. PMID:26086776

  5. Very extended E8 and A8 at low levels, gravity and supergravity

    NASA Astrophysics Data System (ADS)

    West, Peter

    2003-06-01

    We define a level for a large class of Lorentzian Kac-Moody algebras. Using this we find the representation content of very extended AD-3 and E8 (i.e., E11) at low levels in terms of AD-1 and A10 representations, respectively. The results are consistent with the conjectured very extended A8 and E11 symmetries of gravity and maximal supergravity theories given respectively in preprints hep-th/0104081 and hep-th/0107209. We explain how these results provided further evidence for these conjectures.

  6. Superrotation induced by critical-level absorption of gravity waves on Venus - An assessment

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.; Farrell, Brian F.

    1987-01-01

    Critical-level absorption of a continuous spectrum of vertically propagating gravity waves is proposed as the mechanism for supporting the superrotation in the deep Venus atmosphere (below the cloud deck). It is shown that the observed westerly zonal wind effectively separates regions where waves of opposite phase speeds are absorbed, leading to westerly mean-flow acceleration below the clouds and easterly above. Using the diagnostic results of Hou and Goody (1985), a quantitative assessment of the required wave spectrum and fluxes of energy and momentum is obtained, and it is shown that they are compatible with observational constraints.

  7. Evaluation of EIGEN-6C4 by means of various functions of the gravity potential, and by GPS/Leveling

    NASA Astrophysics Data System (ADS)

    Klokocnik, Jaroslav; Kostelecky, Jan; Bucha, Blazej; Bezdek, Ales; Foerste, Christoph

    2015-04-01

    The combined gravity field model EIGEN-6C4 (Foerste et al., 2014) is the latest combined global gravity field model of GFZ Potsdam and GRGS Toulouse. EIGEN-6C4 has been generated including the satellite gravity gradiometry data of the entire GOCE mission (November 2009 till October 2013) and is of maximum spherical degree and order 2190. In this study EIGEN-6C4 has been compared with EGM 2008 to its maximum degree and order via gravity disturbancies, the Marussi tensor of the second derivatives of the disturbing potential, the invariants of the gravity field, their specific combinations, strike angles and virtual deformations over the whole world. The emphasis is put on such areas where GOCE data (complete set of gradiometry measurements after reductions) in EIGEN-6C4 obviously contributes to an improvement of the gravity field description. GNSS/Leveling geoid heights are independent data source for the evaluation of gravity field models. Therefore, we use the GNSS/Leveling data sets over the territories of several countries in Europe, Brazil, the USA, Canada and Japan for the evaluation of EIGEN-6C4 w.r.t. EGM 2008.

  8. High pressure liquid level monitor

    DOEpatents

    Bean, Vern E. (Frederick, MD); Long, Frederick G. (Ijamsville, MD)

    1984-01-01

    A liquid level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

  9. Mars gravity: high-resolution results from viking orbiter 2.

    PubMed

    Sjogren, W L

    1979-03-01

    Doppler radio-tracking data have provided detailed measurements for a martian gravity map extending from 30 degrees S to 65 degrees N in latitude and through 360 degrees of longitude. The feature resolution is approximately 500 kilometers, revealing a huge anomaly associated with Olympus Mons, a mascon in Isidis Planitia, and other anomalies correlated with volcanic structure. Olympus Mons has been modeled with a 600-kilometer surface disk having a mass of 8.7 x 1021grams. PMID:17811123

  10. Scotia Sea tectonics from high-resolution satellite gravity

    NASA Astrophysics Data System (ADS)

    Livermore, Roy; McAdoo, David; Marks, Karen

    1994-05-01

    The release of altimetric data from the Geosat Geodetic Mission by the US Navy [1] is leading to a much-improved understanding of tectonics in the Southern Ocean, a region in which remoteness and adverse physical conditions have limited the acquisition of geophysical data by research ships. The Scotia Sea is an outstanding example of back-arc spreading, which is revealed in some detail by free-air gravity anomaly maps derived from the latest release of data acquired south of 30S [2]. Sea surface height data for this region have been reduced to a grid of free-air gravity anomalies, and are illustrated here by means of colour shaded relief and contour maps. The new data confirm the existence of a number of inactive spreading ridges within the Scotia Sea and surrounding small basins. The amplitudes and wavelengths of gravity anomalies over these ridges conform, in general, to the expected relationship with spreading rate, except in the central Scotia Sea, where a proposed Miocene slow-spreading ridge appears to have left no clear signature. The spreading ridge axis in the east Scotia Sea comprises seven or more segments, separated by small, mainly sinistral, offsets and exhibits a median valley with depths of 200-1000 m that is reflected in free-air lows of 10-40 mGal. Near both its northern and southern termini, the gravity signature of the ridge becomes less distinct, with a less pronounced axial low. The northernmost segments of the ridge are displaced in a right-lateral sense by a feature which appears to represent a southward migrating non-transform offset. Whereas the process of spreading in Drake Passage and the east Scotia Sea was comparable to mid-ocean ridges, that in the central Scotia Sea may have been disorganized, as observed in some western Pacific back-arc basins.

  11. High-resolution gravity and seismic-refraction surveys of the Smoke Tree Wash area, Joshua Tree National Park, California

    USGS Publications Warehouse

    Langenheim, Victoria E.; Rymer, Michael J.; Catchings, Rufus D.; Goldman, Mark R.; Watt, Janet T.; Powell, Robert E.; Matti, Jonathan C.

    2016-01-01

    We describe high-resolution gravity and seismic refraction surveys acquired to determine the thickness of valley-fill deposits and to delineate geologic structures that might influence groundwater flow beneath the Smoke Tree Wash area in Joshua Tree National Park. These surveys identified a sedimentary basin that is fault-controlled. A profile across the Smoke Tree Wash fault zone reveals low gravity values and seismic velocities that coincide with a mapped strand of the Smoke Tree Wash fault. Modeling of the gravity data reveals a basin about 2–2.5 km long and 1 km wide that is roughly centered on this mapped strand, and bounded by inferred faults. According to the gravity model the deepest part of the basin is about 270 m, but this area coincides with low velocities that are not characteristic of typical basement complex rocks. Most likely, the density contrast assumed in the inversion is too high or the uncharacteristically low velocities represent highly fractured or weathered basement rocks, or both. A longer seismic profile extending onto basement outcrops would help differentiate which scenario is more accurate. The seismic velocities also determine the depth to water table along the profile to be about 40–60 m, consistent with water levels measured in water wells near the northern end of the profile.

  12. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and…

  13. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and

  14. High Resolution Measurement of Gravity Deflections from the Vertical over Long Baselines

    NASA Astrophysics Data System (ADS)

    Sander, S.; Ferguson, S.; Sander, L.; Elieff, S. H.

    2011-12-01

    Sander Geophysics has operated its AIRGrav system for over ten years and has worked to continually improve the accuracy and resolution of the entire system. New data processing techniques have allowed the extraction of the gravity deflections from the vertical (horizontal components of the airborne gravity data) in addition to the traditionally used scalar gravity measurement, and operations have expanded to acquisition speeds ranging from 15 km/hr to over 1000 km/hr. The gravimeter is based on an assembly of gyroscopes and accelerometers held in a stable spatial orientation, and has horizontal accelerometers of sufficient accuracy that it is possible to estimate the horizontal components of the gravity vector. "Geodetic quality" GPS receivers are used to collect data at a high rate, and these data are post-processed with the recorded gravimeter data to produce estimates of the three gravity vector components. The estimates of the gravity deflections from the vertical are very sensitive to initial settings of sensor parameters, unmodelled gyro and other sensor errors, as well as unpredictable changes in the sensor errors. As a consequence, it is necessary to constrain the long-wavelength errors using some external source of data. All three components of gravity can be measured to sub-mGal resolution, providing the horizontal components can be constrained in a long-wavelength sense. Data recorded during several flights each consisting of a single long line will be presented, showing the estimates of the gravity deflections from the vertical and comparing them with the best available reference data. Figure 1 illustrates the extent of the long lines. The examples will demonstrate that the horizontal gravity components can be measured with high repeatability, and agree with geoid models of the highest order available. Results from airborne and marine surveys acquired at a wide range of speeds will also be presented to illustrate the resolution attained using these varied platforms.

  15. Ocean contribution to seismic gravity changes: the sea level equation for seismic perturbations revisited

    NASA Astrophysics Data System (ADS)

    Broerse, Taco; Riva, Riccardo; Vermeersen, Bert

    2014-11-01

    During megathrust earthquakes, great ruptures are accompanied by large scale mass redistribution inside the solid Earth and by ocean mass redistribution due to bathymetry changes. These large scale mass displacements can be detected using the monthly gravity maps of the GRACE satellite mission. In recent years it has become increasingly common to use the long wavelength changes in the Earth's gravity field observed by GRACE to infer seismic source properties for large megathrust earthquakes. An important advantage of space gravimetry is that it is independent from the availability of land for its measurements. This is relevant for observation of megathrust earthquakes, which occur mostly offshore, such as the M_{text{w}} 9 2004 Sumatra-Andaman, 2010 Maule (Chile) and 2011 Tohoku-Oki (Japan) events. In Broerse et al., we examined the effect of the presence of an ocean above the rupture on long wavelength gravity changes and showed it to be of the first order. Here we revisit the implementation of an ocean layer through the sea level equation and compare the results with approximated methods that have been used in the literature. One of the simplifications usually lies in the assumption of a globally uniform ocean layer. We show that especially in the case of the 2010 Maule earthquake, due to the closeness of the South American continent, the uniform ocean assumption is not valid and causes errors up to 57 per cent for modelled peak geoid height changes (expressed at a spherical harmonic truncation degree of 40). In addition, we show that when a large amount of slip occurs close to the trench, horizontal motions of the ocean floor play a mayor role in the ocean contribution to gravity changes. Using a slip model of the 2011 Tohoku-Oki earthquake that places the majority of slip close to the surface, the peak value in geoid height change increases by 50 per cent due to horizontal ocean floor motion. Furthermore, we test the influence of the maximum spherical harmonic degree at which the sea level equation is performed for sea level changes occurring along coastlines, which shows to be important for relative sea level changes occurring along the shore. Finally, we demonstrate that ocean floor loading, self-gravitation of water and conservation of water mass are of second order importance for coseismic gravity changes. When GRACE observations are used to determine earthquake parameters such as seismic moment or source depth, the uniform ocean layer method introduces large biases, depending on the location of the rupture with respect to the continent. The same holds for interpreting shallow slip when horizontal motions are not properly accounted for in the ocean contribution. In both cases the depth at which slip occurs will be underestimated.

  16. Ocean Contribution to Seismic Gravity Changes: the Sea Level Equation for Seismic Perturbations Revisited

    NASA Astrophysics Data System (ADS)

    Broerse, T.; Riva, R.; Vermeersen, B. L. A.

    2014-12-01

    During megathrust earthquakes, great ruptures are accompanied by large scale mass redistribution inside the solid Earth and by ocean mass redistribution due to bathymetry changes. These large scale mass displacements can be detected using the monthly gravity maps of the GRACE satellite mission. In recent years it has become increasingly common to use the long wavelength changes in the Earth's gravity field observed by GRACE to infer seismic source properties for large megathrust earthquakes, such as the Mw ~ 9 2004 Sumatra-Andaman, 2010 Maule (Chile) and 2011 Tohoku-Oki (Japan) events. In Broerse et al. (2011) we examined the effect of the presence of an ocean above the rupture on long wavelength gravity changes and showed it to be of the first order. Here we revisit the implementation of an ocean layer through the sea level equation and compare the results with approximated methods that have been used in the literature. One of the simplifications usually lies in the assumption of a globally uniform ocean layer. We show that especially in the case of the 2010 Maule earthquake, due to the closeness of the South American continent, the uniform ocean assumption causes errors up to 57% for modeled peak geoid height changes (expressed at a spherical harmonic truncation degree of 40). In addition, we show that when a large amount of slip occurs close to the trench, horizontal motions of the ocean floor play a mayor role in the ocean contribution to gravity changes. Using a slip model of the 2011 Tohoku-Oki earthquake that places the majority of slip close to the surface, the peak value in geoid height change increases by 50% due to horizontal ocean floor motion. When GRACE observations are used to determine earthquake parameters such as seismic moment or source depth, the uniform ocean layer method introduces large biases, depending on the location of the rupture with respect to the continent. The same holds for interpreting shallow slip when horizontal motions are not properly accounted for in the ocean contribution. In both cases the depth at which slip occurs will be underestimated.

  17. Reply to "Comment on `Highly relativistic spin-gravity coupling for fermions' "

    NASA Astrophysics Data System (ADS)

    Plyatsko, Roman; Fenyk, Mykola

    2016-01-01

    In the context of results presented in [S. A. Hojman and F. A. Asenjo, Classical Quantum Gravity 30, 025008 (2013)], we discuss different formulations of equations which are used to describe motions of a spinning test body (particle) in general relativity. The specific features of the spin-gravity interaction for highly relativistic spinning particles in Schwarzschild's background according to the Mathisson-Papapetrou equations are stressed.

  18. High-degree Gravity Models from GRAIL Primary Mission Data

    NASA Technical Reports Server (NTRS)

    Lemoine, Frank G.; Goossens, Sander J.; Sabaka, Terence J.; Nicholas, Joseph B.; Mazarico, Erwan; Rowlands, David D.; Loomis, Bryant D.; Chinn, Douglas S.; Caprette, Douglas S.; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.

    2013-01-01

    We have analyzed Ka?band range rate (KBRR) and Deep Space Network (DSN) data from the Gravity Recovery and Interior Laboratory (GRAIL) primary mission (1 March to 29 May 2012) to derive gravity models of the Moon to degree 420, 540, and 660 in spherical harmonics. For these models, GRGM420A, GRGM540A, and GRGM660PRIM, a Kaula constraint was applied only beyond degree 330. Variance?component estimation (VCE) was used to adjust the a priori weights and obtain a calibrated error covariance. The global root?mean?square error in the gravity anomalies computed from the error covariance to 320×320 is 0.77 mGal, compared to 29.0 mGal with the pre?GRAIL model derived with the SELENE mission data, SGM150J, only to 140×140. The global correlations with the Lunar Orbiter Laser Altimeter?derived topography are larger than 0.985 between l = 120 and 330. The free?air gravity anomalies, especially over the lunar farside, display a dramatic increase in detail compared to the pre?GRAIL models (SGM150J and LP150Q) and, through degree 320, are free of the orbit?track?related artifacts present in the earlier models. For GRAIL, we obtain an a posteriori fit to the S?band DSN data of 0.13 mm/s. The a posteriori fits to the KBRR data range from 0.08 to 1.5 micrometers/s for GRGM420A and from 0.03 to 0.06 micrometers/s for GRGM660PRIM. Using the GRAIL data, we obtain solutions for the degree 2 Love numbers, k20=0.024615+/-0.0000914, k21=0.023915+/-0.0000132, and k22=0.024852+/-0.0000167, and a preliminary solution for the k30 Love number of k30=0.00734+/-0.0015, where the Love number error sigmas are those obtained with VCE.

  19. High-resolution gravity and geoid models in Tahiti obtained from new airborne and land gravity observations: data fusion by spectral combination

    NASA Astrophysics Data System (ADS)

    Shih, Hsuan-Chang; Hwang, Cheinway; Barriot, Jean-Pierre; Mouyen, Maxime; Corréia, Pascal; Lequeux, Didier; Sichoix, Lydie

    2015-08-01

    For the first time, we carry out an airborne gravity survey and we collect new land gravity data over the islands of Tahiti and Moorea in French Polynesia located in the South Pacific Ocean. The new land gravity data are registered with GPS-derived coordinates, network-adjusted and outlier-edited, resulting in a mean standard error of 17 μGal. A crossover analysis of the airborne gravity data indicates a mean gravity accuracy of 1.7 mGal. New marine gravity around the two islands is derived from Geosat/GM, ERS-1/GM, Jason-1/GM, and Cryosat-2 altimeter data. A new 1-s digital topography model is constructed and is used to compute the topographic gravitational effects. To use EGM08 over Tahiti and Moorea, the optimal degree of spherical harmonic expansion is 1500. The fusion of the gravity datasets is made by the band-limited least-squares collocation, which best integrates datasets of different accuracies and spatial resolutions. The new high-resolution gravity and geoid grids are constructed on a 9-s grid. Assessments of the grids by measurements of ground gravity and geometric geoidal height result in RMS differences of 0.9 mGal and 0.4 cm, respectively. The geoid model allows 1-cm orthometric height determination by GPS and Lidar and yields a consistent height datum for Tahiti and Moorea. The new Bouguer anomalies show gravity highs and lows in the centers and land-sea zones of the two islands, allowing further studies of the density structure and volcanism in the region.

  20. Centrifugal Sieve for Gravity-Level-Independent Size Segregation of Granular Materials

    NASA Technical Reports Server (NTRS)

    Walton, Otis R.; Dreyer, Christopher; Riedel, Edward

    2013-01-01

    Conventional size segregation or screening in batch mode, using stacked vibrated screens, is often a time-consuming process. Utilization of centrifugal force instead of gravity as the primary body force can significantly shorten the time to segregate feedstock into a set of different-sized fractions. Likewise, under reduced gravity or microgravity, a centrifugal sieve system would function as well as it does terrestrially. When vibratory and mechanical blade sieving screens designed for terrestrial conditions were tested under lunar gravity conditions, they did not function well. The centrifugal sieving design of this technology overcomes the issues that prevented sieves designed for terrestrial conditions from functioning under reduced gravity. These sieves feature a rotating outer (cylindrical or conical) screen wall, rotating fast enough for the centrifugal forces near the wall to hold granular material against the rotating screen. Conventional centrifugal sieves have a stationary screen and rapidly rotating blades that shear the granular solid near the stationary screen, and effect the sieving process assisted by the airflow inside the unit. The centrifugal sieves of this new design may (or may not) have an inner blade or blades, moving relative to the rotating wall screen. Some continuous flow embodiments would have no inner auger or blades, but achieve axial motion through vibration. In all cases, the shearing action is gentler than conventional centrifugal sieves, which have very high velocity differences between the stationary outer screen and the rapidly rotating blades. The new design does not depend on airflow in the sieving unit, so it will function just as well in vacuum as in air. One advantage of the innovation for batch sieving is that a batch-mode centrifugal sieve may accomplish the same sieving operation in much less time than a conventional stacked set of vibrated screens (which utilize gravity as the primary driving force for size separation). In continuous mode, the centrifugal sieves can provide steady streams of fine and coarse material separated from a mixed feedstock flow stream. The centrifugal sieves can be scaled to any desired size and/or mass flow rate. Thus, they could be made in sizes suitable for small robotic exploratory missions, or for semi-permanent processing of regolith for extraction of volatiles of minerals. An advantage of the continuous-mode system is that it can be made with absolutely no gravity flow components for feeding material into, or for extracting the separated size streams from, the centrifugal sieve. Thus, the system is capable of functioning in a true microgravity environment. Another advantage of the continuous-mode system is that some embodiments of the innovation have no internal blades or vanes, and thus, can be designed to handle a very wide range of feedstock sizes, including occasional very large oversized pieces, without jamming or seizing up.

  1. Effect of Gravity Level on the Particle Shape and Size During Zeolite Crystal Growth

    NASA Technical Reports Server (NTRS)

    Song, Hong-Wei; Ilebusi, Olusegun J.; Sacco, Albert, Jr.

    2003-01-01

    A microscopic diffusion model is developed to represent solute transport in the boundary layer of a growing zeolite crystal. This model is used to describe the effect of gravity on particle shape and solute distribution. Particle dynamics and crystal growth kinetics serve as the boundary conditions of flow and convection-diffusion equations. A statistical rate theory is used to obtain the rate of solute transport across the growing interface, which is expressed in terms of concentration and velocity of solute species. Microgravity can significantly decrease the solute velocity across the growing interface compared to its earth-based counterpart. The extent of this reduction highly depends on solute diffusion constant in solution. Under gravity, the flow towards the crystal enhances solute transport rate across the growing interface while the flow away from crystals reduces this rate, suggesting a non-uniform growth rate and thus an elliptic final shape. However, microgravity can significantly reduce the influence of flow and obtain a final product with perfect spherical shape. The model predictions compare favorably with the data of space experiment of zeolites grown in space.

  2. High Degree and Order Gravity Fields of the Moon Derived from GRAIL Data

    NASA Technical Reports Server (NTRS)

    Lemoine, F. G.; Goossens, S. J.; Sabaka, T. J.; Nicholas, J. B.; Mazarico, E.; Rowlands, D. D.; Loomis, B. D.; Chinn, D. S.; Caprette, D. S.; McCarthy, J. J.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

    2012-01-01

    The Gravity Recovery and Interior Laboratory (GRAIL) spacecraft conducted the mapping of the gravity field of the Moon from March 1, 2012 to May 29, 2012. The twin spacecraft acquired highly precise K Band range-rate (KBRR) intersatellite ranging data and Deep Space Network (DSN) data during this prime mission phase from altitudes of 15 to 75 km above the lunar surface over three lunar months. We have processed these data using the NASA GSFC GEODYN orbit determination and geodetic parameter estimation program, and we have determined gravity fields up to degree and order 420 in spherical harmonics. The new gravity solutions show improved correlations with LOLA-derived topography to high degree and order and resolve many lunar features in the geopotential with a resolution of less than 30 km, including for example the central peak of the crater Tycho. We discuss the methodology used for the processing of the GRAIL data, the quality of the orbit determination on the GRAIL satellites and the derivation of the solutions, and their evaluation with independent data, including Lunar Prospector. We show that with these new GRAIL gravity solutions, we can now fit the low altitude, extended mission Lunar Prospector tracking data better than with any previous gravity model that included the LP data.

  3. Figuring large optics at the sub-nanometer level: compensation for coating and gravity distortions.

    PubMed

    Gensemer, Stephen; Gross, Mark

    2015-11-30

    Large, precision optics can now be manufactured with surface figures specified at the sub-nanometer level. However, coatings and gravity deform large optics, and there are limits to what can be corrected by clever compensation. Instead, deformations caused by stress from optical mounts and deposited coatings must be incorporated into the optical design. We demonstrate compensation of coating stress on a 370mm substrate to ?/200 by a process of coating and annealing. We also model the same process and identify the leading effects that must be anticipated in fabrication of optics for future gravitational wave detectors and other applications of large, precisely figured optics, and identify the limitations inherent in using coatings to compensate for these deformations. PMID:26698746

  4. Importance of terrestrial surface density information and satellite-aided global gravity field models for high precision regional geoid computation

    NASA Astrophysics Data System (ADS)

    Pock, Christian; Mayer-Grr, Torsten; Rieser, Daniel; Khtreiber, Norbert

    2015-04-01

    High precision regional geoid determination is a challenging task. Besides the quality of the input data, the quality of the global gravity field data and the density information is essential for a consistent treatment of the gravity field quantities within the remove-compute-restore procedure. In this investigation a surface density model based on geological observations is introduced, replacing the constant standard crustal density. The long-wavelength component of the gravity field is represented by the GOCO05s global gravity field model. The geoid computation is based on a Gauss-Markov model with radial basis function parametrization. The achieved improvements are remarkable and lead to an unprecedented accuracy of the pure gravimetric geoid in Austria. As final outcomes a new geoid solution and a map for the xi and eta components of deflections of the vertical are computed. The achieved results are primarily validated with independent GPS/leveling observations. Secondly validation has been carried out through deflections of the vertical, obtained from precise zenith camera and astronomical measurements. Furthermore, differences between the current official Austrian geoid solution based on data from 2008 and the new estimated geoid are shown. An overview about the achieved improvements and the validation is given in the presentation.

  5. Lunar Prospector Orbit Determination Uncertainties Using the High Resolution Lunar Gravity Models

    NASA Technical Reports Server (NTRS)

    Carranza, Eric; Konopliv, Alex; Ryne, Mark

    1999-01-01

    The Lunar Prospector (LP) mission began on January 6, 1998, when the LP spacecraft was launched from Cape Canaveral, Florida. The objectives of the mission were to determine whether water ice exists at the lunar poles, generate a global compositional map of the lunar surface, detect lunar outgassing, and improve knowledge of the lunar magnetic and gravity fields. Orbit determination of LP performed at the Jet Propulsion Laboratory (JPL) is conducted as part of the principal science investigation of the lunar gravity field. This paper will describe the JPL effort in support of the LP Gravity Investigation. This support includes high precision orbit determination, gravity model validation, and data editing. A description of the mission and its trajectory will be provided first, followed by a discussion of the orbit determination estimation procedure and models. Accuracies will be examined in terms of orbit-to-orbit solution differences, as a function of oblateness model truncation, and inclination in the plane-of-sky. Long term predictions for several gravity fields will be compared to the reconstructed orbits to demonstrate the accuracy of the orbit determination and oblateness fields developed by the Principal Gravity Investigator.

  6. Testing Plate Reconstructions For The High Arctic Using Crustal Thickness Mapping From Gravity Inversion

    NASA Astrophysics Data System (ADS)

    Alvey, A. D.; Gaina, C.; Kusznir, N. J.; Torsvik, T. H.

    2006-12-01

    The plate tectonic history of the Amerasia Basin (High Arctic) and its distribution of oceanic and continental lithosphere is poorly known. A new method of gravity inversion with an embedded lithosphere thermal gravity anomaly correction has been applied to the NGA (U) Arctic Gravity Project data to predict crustal thickness and to test different plate reconstructions within the Arctic region. Two end member plate reconstruction models have been tested: in one model the Mendeleev Ridge is rifted from the Canadian margin while in the other it is rifted from the Lomonosov Ridge. The inversion of gravity data to map crustal thickness variation within oceanic and rifted continental margin lithosphere requires the incorporation of a lithosphere thermal gravity anomaly correction for both oceanic and continental lithosphere. Oceanic lithosphere and stretched continental margin lithosphere produce a large negative residual thermal gravity anomaly (up to -380 mGal), for which a correction must be made in order to determine realistic Moho depth by gravity anomaly inversion. The lithosphere thermal model used to predict the lithosphere thermal gravity anomaly correction may be conditioned using plate reconstruction models to provide the age and location of oceanic lithosphere. Two end- member plate reconstruction models have been constructed for the opening of the Amerasia Basin and used to determine lithosphere thermal gravity anomaly corrections: in one model the (presumably) continental Mendeleev Ridge is rifted from the Canadian margin in the Jurassic while in the other it is rifted off the Lomonosov Ridge (Eurasia Basin) in the Late-Cretaceous. Crustal thickness predicted by gravity anomaly inversion for the two plate reconstructions is significantly different in the Makarov Basin because of their different lithosphere thermal gravity corrections. The plate reconstruction with younger Makarov Basin ages gives a crustal thickness of the order 6-8 km thinner than the older Makarov Basin model. A crustal thickness of approximately 20 km has been obtained from seismic refraction data (Lebedeva-Ivanova et al., 2006) which would imply a Late Mid-Cretaceous age for the Makarov Basin. In this case plume-related forces may have contributed to the opening of this basin, as regional plate tectonics predict compression and not extension in the Makarov Basin area at this time.

  7. On the concentration structure of high-concentration constant-volume fluid mud gravity currents

    NASA Astrophysics Data System (ADS)

    Jacobson, M. R.; Testik, F. Y.

    2013-01-01

    An exhaustive laboratory experimental campaign was undertaken in order to elucidate the concentration structure of two-dimensional constant-volume non-Newtonian fluid mud gravity currents. Two sets of experiments were conducted in a lock-exchange tank. The first set of experiments involved measuring the vertical concentration profiles using a siphoning technique; the second set involved auxiliary visual observations. The first set of experiments consisted of 32 experimental runs for four different experimental conditions, with an array of siphoned samples being withdrawn throughout the head and body of the gravity current. From these samples, vertical concentration profiles occurring in constant-volume fluid mud gravity currents were classified and the underlying physical processes that led to the occurrence of observed profiles were discussed. Furthermore, the functional form of the vertical concentration profiles within the head of relatively low-initial-concentration gravity currents was proposed. The relatively high-initial-concentration gravity currents revealed the presence of a lutocline in the current head and body, the presence of which was observed for constant-flux release gravity currents. To our knowledge, this is the first measurement of a lutocline in constant-volume gravity currents. Abrupt transitions, a phenomenon in which the bulk of the suspended sediment in the propagating gravity current drops out, were observed through the concentration profiles and through 15 auxiliary visual experimental runs. It was found that abrupt transitions were caused by the presence of a lutocline. The entrainment of ambient water resulting in the dilution of the gravity current at different concentration contours has been quantified. In a previous work by the authors of this study, it was shown that the initial reduced gravity is directly proportional to the growth rate of the visual area of the two-dimensional current. The analysis of our experimental observations presented in this study, however, showed the initial reduced gravity to be inversely proportional to the growth rate of the area enclosed by concentration contours with higher values than that of the visual area. These seemingly opposing conclusions are rationalized and the considerable practical impacts are discussed.

  8. Glacier mass balance in high-arctic areas with anomalous gravity

    NASA Astrophysics Data System (ADS)

    Sharov, A.; Rieser, D.; Nikolskiy, D.

    2012-04-01

    All known glaciological models describing the evolution of Arctic land- and sea-ice masses in changing climate treat the Earth's gravity as horizontally constant, but it isn't. In the High Arctic, the strength of the gravitational field varies considerably across even short distances under the influence of a density gradient, and the magnitude of free air gravity anomalies attains 100 mGal and more. On long-term base, instantaneous deviations of gravity can have a noticeable effect on the regime and mass budget of glaciological objects. At best, the gravity-induced component of ice mass variations can be determined on topographically smooth, open and steady surfaces, like those of arctic planes, regular ice caps and landfast sea ice. The present research is devoted to studying gravity-driven impacts on glacier mass balance in the outer periphery of four Eurasian shelf seas with a very cold, dry climate and rather episodic character of winter precipitation. As main study objects we had chosen a dozen Russia's northernmost insular ice caps, tens to hundreds of square kilometres in extent, situated in a close vicinity of strong gravity anomalies and surrounded with extensive fields of fast and/or drift ice for most of the year. The supposition about gravitational forcing on glacioclimatic settings in the study region is based on the results of quantitative comparison and joint interpretation of existing glacier change maps and available data on the Arctic gravity field and solid precipitation. The overall mapping of medium-term (from decadal to half-centennial) changes in glacier volumes and quantification of mass balance characteristics in the study region was performed by comparing reference elevation models of study glaciers derived from Russian topographic maps 1:200,000 (CI = 20 or 40 m) representing the glacier state as in the 1950s-1980s with modern elevation data obtained from satellite radar interferometry and lidar altimetry. Free-air gravity anomalies were graphically represented in the reference model geometry using Russian gravimetric maps 1:1000000 (1980s), ArcGP grid (2008) and GOCE gravity field data (Release 3, 2009-2011). 25-year long records of daily precipitation obtained from 38 coastal stations were involved in the causality analysis. Strong positive distance-weighted correlation was discovered between the magnitude of geopotential and gravity gradient on one hand and the precipitation amount, annual number of precipitation "events" and glacier elevation changes on the other, while it was noted that the correlation decreases in humid and mountainous areas. Relevant analytical and geophysical explanations were provided and tested using the basic concepts of hydrostatic stress, lapse rate and non-orographic gradient precipitation. It was concluded that the gravitational impact on the mass balance of arctic maritime ice caps is threefold. 1) Lateral variations of gravity influence directly the ambient lapse rate thereby modulating the atmospheric stability and leading to the increased intensity and frequency of heavy snowfalls over the areas with positive gravity anomalies. 2) Glacier ice deformation, flow, calving and meltwater runoff are gravity-driven phenomena, and the removal of glacier ice is closely interrelated with geopotential variations nearby. 3) Gravity anomalies affect processes of sea ice grow, drift and consolidation resulting in generally lower concentration and lesser thickness of the sea ice found in the aquatories with positive gravity. The advection of moist air to insular ice caps facilitates sea-effect snow events and makes glacier mass balance more positive. The effect is enhanced when the air mass advects toward the centre of positive anomaly. The idea about gradient (deviatoric) precipitation and related cryogravic processes does not contradict to the concept of gravity waves and has some analogy with the hypothesis on "ice lichens" devised by E.Gernet 80 years ago. Further analogies can be learned from another industry, e.g. technical chemistry. Several quest

  9. Virtuous trees at five- and six-point levels for Yang-Mills theory and gravity

    SciTech Connect

    Broedel, Johannes; Carrasco, John Joseph M.

    2011-10-15

    We present a particularly nice D-dimensional graph-based representation of the full color-dressed five-point tree-level gluon amplitude. It possesses the following virtues: (1) it satisfies the color-kinematic correspondence, and thus trivially generates the associated five-point graviton amplitude, (2) all external-state information is encoded in color-ordered partial amplitudes, and (3) one function determines the kinematic contribution of all graphs in the Yang-Mills amplitude, so the associated gravity amplitude is manifestly permutation symmetric. The third virtue, while shared among all known loop-level correspondence-satisfying representations, is novel for tree-level representations sharing the first two virtues. This new D-dimensional representation makes contact with the recently found multiloop five-point representations, suggesting all-loop, all-multiplicity ramifications through unitarity. Additionally we present a slightly less virtuous representation of the six-point maximally helicity-violating (MHV) and MHV amplitudes that holds only in four dimensions.

  10. Gain of balance and critical level absorption for inertio gravity waves

    NASA Astrophysics Data System (ADS)

    Lott, Francois; Millet, Christophe; Vanneste, Jacques

    2014-05-01

    The absorption of an inertio gravity wave (IGW) at critical levels is analyzed in the rotating linear case, and for a constant vertically sheared flow. We give for the first time an exact solution valid over the entire domain, and check its validity by deriving from it the classical values of the transmission and reflection coefficients of the wave |T| = exp( ) - ?J-(1+-?2)-0.25- and |R| = 0, respectively. Here J is the Richardson number and ? the ratio between the horizontal transverse and along shear wavenumbers. For large J, a WKB analysis permits to interpret this classical result in term of tunneling. In this interpretation, the wave as it arrives to the lowest inertial critical level becomes evanescent (there is a turning point very near the critical level), and the transmitted signal is just the amplitude of this evanescent disturbance at the upper inertial level where it becomes an IGW again. As this evanescent solution is near a quasi-geostrophic solution between the inertial levels we see that it is a gain of balance there that explain the exponential smallness of the transmitted wave. The exact and approximate solutions also permit to describe how the "valve" effect, which amplify the disturbances with phase line tilted in the direction of the isentropes, is only significant when the flow is inertially unstable (when J < 1). In this case, a small incident asymmetric transverse wave can result in a very large disturbance between the inertial levels, a result that establish a correspondence between the absoptive properties of the shear layer and the criteria for flow stability.

  11. ALTURAS: A MULTI-PURPOSE RUSSET POTATO CULTIVAR WITH HIGH YIELD AND SPECIFIC GRAVITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alturas, a late- maturing, high-yielding, russet potato cultivar with high tuber specific gravity, was released in 2002 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington. Originally selected for dehydration processing, its cold-sweetening resistance also make...

  12. Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions

    NASA Technical Reports Server (NTRS)

    Wang, Y.; Gupta, A. K.

    2001-01-01

    The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

  13. High gravity and high cell density mitigate some of the fermentation inhibitory effects of softwood hydrolysates

    PubMed Central

    2013-01-01

    After steam pretreatment of lignocellulosic substrates the fermentation of the biomass derived sugars to ethanol is typically problematic because of both the generally low sugar concentrations that can be supplied and the presence of naturally occurring and process derived inhibitors. As the majority of the inhibitory materials are usually associated with the hemicellulose rich, water soluble component, this fraction was supplemented with glucose to simulate high solids, un-detoxified substrate to see if a high gravity/high cell consistency approach might better cope with inhibition. Several yeast strains were assessed, with the Tembec T1, T2 and Lallemand LYCC 6469 strains showing the greatest ethanol productivity and yield. The addition of supplemental glucose enabled the faster and quantitatively higher removal of hydroxymethylfurfural (HMF). High cell density could provide effective fermentation at high sugar concentrations while enhancing inhibitor reduction. A 77% ethanol yield could be achieved using strain LYCC 6469 after 48 h at high cell density. It was apparent that a high cell density approach improved ethanol production by all of the evaluated yeast strains. PMID:23410516

  14. Very high gravity (VHG) ethanolic brewing and fermentation: a research update.

    PubMed

    Puligundla, Pradeep; Smogrovicova, Daniela; Obulam, Vijaya Sarathi Reddy; Ko, Sanghoon

    2011-09-01

    There have been numerous developments in ethanol fermentation technology since the beginning of the new millennium as ethanol has become an immediate viable alternative to fast-depleting crude reserves as well as increasing concerns over environmental pollution. Nowadays, although most research efforts are focused on the conversion of cheap cellulosic substrates to ethanol, methods that are cost-competitive with gasoline production are still lacking. At the same time, the ethanol industry has engaged in implementing potential energy-saving, productivity and efficiency-maximizing technologies in existing production methods to become more viable. Very high gravity (VHG) fermentation is an emerging, versatile one among such technologies offering great savings in process water and energy requirements through fermentation of higher concentrations of sugar substrate and, therefore, increased final ethanol concentration in the medium. The technology also allows increased fermentation efficiency, without major alterations to existing facilities, by efficient utilization of fermentor space and elimination of known losses. This comprehensive research update on VHG technology is presented in two main sections, namely VHG brewing, wherein the effects of nutrients supplementation, yeast pitching rate, flavour compound synthesis and foam stability under increased wort gravities are discussed; and VHG bioethanol fermentation studies. In the latter section, aspects related to the role of osmoprotectants and nutrients in yeast stress reduction, substrates utilized/tested so far, including saccharide (glucose, sucrose, molasses, etc.) and starchy materials (wheat, corn, barley, oats, etc.), and mash viscosity issues in VHG bioethanol production are detailed. Thereafter, topics common to both areas such as process optimization studies, mutants and gene level studies, immobilized yeast applications, temperature effect, reserve carbohydrates profile in yeast, and economic aspects are discussed and future prospects are summarized. PMID:21695540

  15. Venus gravity

    NASA Technical Reports Server (NTRS)

    Reasenberg, Robert D.

    1993-01-01

    The anomalous gravity field of Venus shows high correlation with surface features revealed by radar. We extract gravity models from the Doppler tracking data from the Pioneer Venus Orbiter (PVO) by means of a two-step process. In the first step, we solve the nonlinear spacecraft state estimation problem using a Kalman filter-smoother. The Kalman filter was evaluated through simulations. This evaluation and some unusual features of the filter are discussed. In the second step, we perform a geophysical inversion using a linear Bayesian estimator. To allow an unbiased comparison between gravity and topography, we use a simulation technique to smooth and distort the radar topographic data so as to yield maps having the same characteristics as our gravity maps. The maps presented cover 2/3 of the surface of Venus and display the strong topography-gravity correlation previously reported. The topography-gravity scatter plots show two distinct trends.

  16. High-resolution simulations of non-Boussinesq downslope gravity currents in the acceleration phase

    NASA Astrophysics Data System (ADS)

    Dai, Albert; Huang, Yu-lin

    2016-02-01

    Gravity currents generated from an instantaneous buoyancy source of density contrast in the density ratio range of 0.3 ≤ γ ≤ 0.998 propagating downslope in the slope angle range of 0° ≤ θ < 90° have been investigated in the acceleration phase by means of high-resolution two-dimensional simulations of the incompressible variable-density Navier-Stokes equations. For all density contrasts considered in this study, front velocity history shows that, after the heavy fluid is released from rest, the gravity currents go through the acceleration phase, reaching a maximum front velocity Uf,max, followed by the deceleration phase. It is found that Uf,max increases as the density contrast increases and such a relationship is, for the first time, quantitatively described by the improved thermal theory considering the non-Boussinesq effects. Energy budgets show that, as the density contrast increases, the heavy fluid retains more fraction of potential energy loss while the ambient fluid receives less fraction of potential energy loss in the process of energy transfer during the propagation of downslope gravity currents. Previously, it was reported that for the Boussinesq case, the downslope gravity currents have a maximum of Uf,max at θ ≈ 40°. It is found, as is also confirmed by the energy budgets in this study, that the slope angle at which the downslope gravity currents have a maximum of Uf,max may increase beyond 40° as the density contrast increases.

  17. On the recovery of gravity anomalies from high precision altimeter data

    NASA Technical Reports Server (NTRS)

    Lelgemann, D.

    1976-01-01

    A model for the recovery of gravity anomalies from high precision altimeter data is derived which consists of small correction terms to the inverse Stokes' formula. The influence of unknown sea surface topography in the case of meandering currents such as the Gulf Stream is discussed. A formula was derived in order to estimate the accuracy of the gravity anomalies from the known accuracy of the altimeter data. It is shown that for the case of known harmonic coefficients of lower order the range of integration in Stokes inverse formula can be reduced very much.

  18. A high-resolution gravimetric geoid model for Japan from EGM2008 and local gravity data

    NASA Astrophysics Data System (ADS)

    Odera, Patroba Achola; Fukuda, Yoichi; Kuroishi, Yuki

    2012-05-01

    A high-resolution geoid model covering the four main islands of Japan has been developed on a 1 by 1.5 arc-minute grid from EGM2008 and terrestrial gravity data. The Stokes-Helmert scheme in a modified form is applied for the determination of the geoid using an empirically-determined optimal spherical cap, and Kriging is used for gridding the residual gravity anomalies. In comparison with the previous geoid model for Japan (JGEOID2008), there is a slight improvement in the standard deviation from 8.44 cm to 8.29 cm. It is noted that although the determined gravimetric geoid model represents the geoid over Japan fairly well, there is still a need for more gravity data especially in the northern parts of Japan.

  19. Evidence of high frequency gravity wave forcing on the meridional residual circulation at the mesopause region

    NASA Astrophysics Data System (ADS)

    Vargas, Fabio; Swenson, Gary; Liu, Alan

    2015-11-01

    Data of high frequency gravity wave propagation direction from globally distributed stations indicate a meridional preference of mesospheric gravity waves to be globally oriented toward the summer pole. This orientation is opposite to the mean residual circulation (from summer to winter pole) at mesospheric altitudes. We discuss here a number of dynamic mechanisms including filtering that may be responsible for the preferential wave orientation, and the effects of the gravity wave forcing imposed on the meridional flow due to dissipative waves. Using nightglow image data recorded in three distinct latitude stations, we have estimated the meridional wave drag (i.e, deceleration) of about - 4.6 0.2 m/s/day during the summer, and 3.8 0.2 m/s/day during the winter, which is significant because the meridional flow has small magnitude. This is a component of dynamic forcing in the mesopause region, not heretofore recognized.

  20. Evaluation of EGM2008 Earth Gravitational Model in Algeria using gravity and GPS/levelling data

    NASA Astrophysics Data System (ADS)

    Benahmed Daho, S. A.

    2009-04-01

    The present work focuses on the evaluation of the EGM2008 geopotential model that was recently released by the NGA (National Geospatial-Intelligence Agency, U.S)/EGM-development team, in Algeria using the free air gravity anomalies supplied by BGI and GETECH, some of the precise GPS data collected from the international TYRGEONET (TYRhenian GEOdynamical NETwork) and ALGEONET (ALGerian GEOdynamical NETwork) projects and the last Algerian local gravimetric geoid model. Additional comparisons of the terrestrial point data with the corresponding values obtained from other geopotential models were made. Five global geopotential models were used in this comparison: the Preliminary Earth Gravitational Model PGM2007A, the combined CHAMP and GRACE model EIGEN-CG01C, the combined GRACE and LAGEOS model EIGEN-GL04C, OSU91A and EGM96. The study shows that all tested models are an improvement over OSU91A geopotential model used in all previous Algerian geoid computations and that new released combined model (EGM2008) is relatively superior to other tested models in the Algerian region. According to our numerical results, the new EGM2008 model fits better the observed values used in this investigation. Its standard deviations fit with GPS/levelling data are 21.4cm and 18.7cm before and after fitting using four-parameters transformation model. We strongly recommend the use of this new model in the remove-restore technique for the computation of the improved geoid for Algeria. In addition to these more general investigations, special GPS campaign has been performed for altimetric auscultation of a storage tank in which we wanted to test the possibilities to replace levelling by GPS measurements. The evaluation revealed promising results but also that much attention has to be paid on the GPS evaluation method. Key words: Geopotential model, TYRGEONET and ALGEONET projects, GPS/levelling data.

  1. Optimizing High Level Waste Disposal

    SciTech Connect

    Dirk Gombert

    2005-09-01

    If society is ever to reap the potential benefits of nuclear energy, technologists must close the fuel-cycle completely. A closed cycle equates to a continued supply of fuel and safe reactors, but also reliable and comprehensive closure of waste issues. High level waste (HLW) disposal in borosilicate glass (BSG) is based on 1970s era evaluations. This host matrix is very adaptable to sequestering a wide variety of radionuclides found in raffinates from spent fuel reprocessing. However, it is now known that the current system is far from optimal for disposal of the diverse HLW streams, and proven alternatives are available to reduce costs by billions of dollars. The basis for HLW disposal should be reassessed to consider extensive waste form and process technology research and development efforts, which have been conducted by the United States Department of Energy (USDOE), international agencies and the private sector. Matching the waste form to the waste chemistry and using currently available technology could increase the waste content in waste forms to 50% or more and double processing rates. Optimization of the HLW disposal system would accelerate HLW disposition and increase repository capacity. This does not necessarily require developing new waste forms, the emphasis should be on qualifying existing matrices to demonstrate protection equal to or better than the baseline glass performance. Also, this proposed effort does not necessarily require developing new technology concepts. The emphasis is on demonstrating existing technology that is clearly better (reliability, productivity, cost) than current technology, and justifying its use in future facilities or retrofitted facilities. Higher waste processing and disposal efficiency can be realized by performing the engineering analyses and trade-studies necessary to select the most efficient methods for processing the full spectrum of wastes across the nuclear complex. This paper will describe technologies being evaluated at Idaho National Laboratory and the facilities weve designed to evaluate options and support optimization.

  2. High-resolution global and local lunar gravity field models using GRAIL mission data

    NASA Astrophysics Data System (ADS)

    Goossens, S. J.; Lemoine, F. G.; Sabaka, T. J.; Nicholas, J. B.; Mazarico, E.; Rowlands, D. D.; Neumann, G. A.; Loomis, B.; Chinn, D. S.; Smith, D. E.; Zuber, M. T.

    2014-12-01

    The Gravity Recovery and Interior Laboratory (GRAIL) spacecraft were designed to map the structure of the Moon through high-precision global gravity mapping. The mission consisted of two spacecraft with Ka-band inter-satellite tracking complemented by tracking from Earth. The mission had two phases: (1) a primary mapping mission from March 1 until May 29, 2012 at an average altitude of 50 km; (2) an extended mission from August 30 until December 14, 2012, with an average altitude of 23 km before November 18, and between 11-20 km through December 14. Both the primary and the extended mission data have been processed into global models of the lunar gravity field at NASA/GSFC using the GEODYN software. Here we present our latest global model, an expansion in spherical harmonics of degree and order 1080. We discuss this new solution in terms of its power spectrum, its free-air and Bouguer anomalies, its associated error spectrum, and its correlations with topography-induced gravity. In addition to global models we also estimated local gravity adjustments in areas of particular interest such as Mare Orientale and the south pole area. We express gravity in terms of anomalies, and estimate them with respect to a global background model. We apply neighbor-smoothing in our estimation procedure. We present a local solution over the south pole area in a resolution of 1/6 by 1/6 of a degree, equivalent to degree and order 1080, and we compare this local solution to our global model.

  3. Cell recycling during repeated very high gravity bio-ethanol fermentations using the industrial Saccharomyces cerevisiae strain PE-2.

    PubMed

    Pereira, Francisco B; Gomes, Daniel G; Guimares, Pedro M R; Teixeira, Jos A; Domingues, Luclia

    2012-01-01

    A very high gravity (VHG) repeated-batch fermentation system using an industrial strain of Saccharomyces cerevisiae PE-2 (isolated from sugarcane-to-ethanol distillery in Brazil) and mimicking industrially relevant conditions (high inoculation rates and low O(2) availability) was successfully operated during fifteen consecutive fermentation cycles, attaining ethanol at 17.1 0.2% (v/v) with a batch productivity of 3.5 0.04 g l(-1) h(-1). Moreover, this innovative operational strategy (biomass refreshing step) prevented critical decreases on yeast viability levels and promoted high accumulation of intracellular glycerol and trehalose, which can provide an adaptive advantage to yeast cells under harsh industrial environments. This study contributes to the improvement of VHG fermentation processes by exploring an innovative operational strategy that allows attaining very high ethanol titres without a critical decrease of the viability level thus minimizing the production costs due to energy savings during the distillation process. PMID:21898130

  4. Development of high accuracy and resolution geoid and gravity maps

    NASA Technical Reports Server (NTRS)

    Gaposchkin, E. M.

    1986-01-01

    Precision satellite to satellite tracking can be used to obtain high precision and resolution maps of the geoid. A method is demonstrated to use data in a limited region to map the geopotential at the satellite altitude. An inverse method is used to downward continue the potential to the Earth surface. The method is designed for both satellites in the same low orbit.

  5. High temperature liquid level sensor

    DOEpatents

    Tokarz, Richard D. (West Richland, WA)

    1983-01-01

    A length of metal sheathed metal oxide cable is perforated to permit liquid access to the insulation about a pair of conductors spaced close to one another. Changes in resistance across the conductors will be a function of liquid level, since the wetted insulation will have greater electrical conductivity than that of the dry insulation above the liquid elevation.

  6. Gravity gradiometry on high-T{sub c} superconducting sensors

    SciTech Connect

    Kraus, R.; Cogbill, A.; Stettler, M.

    1996-09-01

    This is the final report of a 1-y LDRD project at LANL. Earth`s gravitational field has minuscule local variations that are difficult to observe with any but the most sensitive instruments. These variations are caused by local variations in the earth`s crust density such as voids or high density material. Such anomalies can be observed directly by mapping the magnitude of the gravitational field (gravimetry) or by measuring the gradient of the gravitational field (gradiometry). It is believed that gradiometry is potentially superior to gravimetry because measurement and interpretation is simpler and less susceptible to masking by other effects, e.g. accelerations. This method introduces no energy or radiation into the region of interest, can be adapted to moving platforms and the capability to take real-time data over large areas is feasible. Scope of this work was to examine feasiiblity and performance of a fieldable gradiometer using high-{Tc} materials.

  7. Exploration of Anomalous Gravity Effects by rf-Pumped Magnetized High-T(c) Superconducting Oxides

    NASA Technical Reports Server (NTRS)

    Robertson, Tony; Litchford, Ron; Peters, Randall; Thompson, Byran; Rodgers, Stephen L. (Technical Monitor)

    2001-01-01

    A number of anomalous gravitational effects have been reported in the scientific literature during recent years, but there has been no independent confirmation with regard to any of these claims. Therefore, the NASA Marshall Space Flight Center, in response to the propulsion challenges specified by NASA's Breakthrough Propulsion Physics (BPP) program, proposed to explore the possibility of observing anomalous gravitation behavior through the manipulation of Josephson junction effects in magnetized high-Tc superconducting oxides. The technical goal was to critically test this revolutionary physical claim and provide a rigorous, independent, empirical confirmation (or refutation) of anomalous effects related to the manipulation of gravity by radio frequency (rf)-pumped magnetized type-2 superconductors. Because the current empirical evidence for gravity modification is anecdotal, our objective was to design, construct, and meticulously implement a discriminating experiment, which would put these observations on a more firm footing within the scientific community. Our approach is unique in that we advocate the construction of an extremely sensitive torsion balance with which to measure gravity modification effects by rf-pumped type-2 superconductor test masses. This paper reviews the anecdotal evidence for anomalous gravity effects, describes the design and development of a simplified torsion balance experiment for empirically investigating these claims, and presents the results of preliminary experiments.

  8. High Sensitivity Gravity Measurements in the Adverse Environment of Oil Wells

    NASA Astrophysics Data System (ADS)

    Pfutzner, Harold

    2014-03-01

    Bulk density is a primary measurement within oil and gas reservoirs and is the basis of most reserves calculations by oil companies. The measurement is performed with a gamma-ray source and two scintillation gamma-ray detectors from within newly drilled exploration and production wells. This nuclear density measurement, while very precise is also very shallow and is therefore susceptible to errors due to any alteration of the formation and fluids in the vicinity of the borehole caused by the drilling process. Measuring acceleration due to gravity along a well provides a direct measure of bulk density with a very large depth of investigation that makes it practically immune to errors from near-borehole effects. Advances in gravity sensors and associated mechanics and electronics provide an opportunity for routine borehole gravity measurements with comparable density precision to the nuclear density measurement and with sufficient ruggedness to survive the rough handling and high temperatures experienced in oil well logging. We will describe a borehole gravity meter and its use under very realistic conditions in an oil well in Saudi Arabia. The density measurements will be presented. Alberto Marsala (2), Paul Wanjau (1), Olivier Moyal (1), and Justin Mlcak (1); (1) Schlumberger, (2) Saudi Aramco.

  9. Influence of high gravity process conditions on the environmental impact of ethanol production from wheat straw.

    PubMed

    Janssen, Matty; Tillman, Anne-Marie; Cannella, David; Jrgensen, Henning

    2014-12-01

    Biofuel production processes at high gravity are currently under development. Most of these processes however use sugars or first generation feedstocks as substrate. This paper presents the results of a life cycle assessment (LCA) of the production of bio-ethanol at high gravity conditions from a second generation feedstock, namely, wheat straw. The LCA used lab results of a set of 36 process configurations in which dry matter content, enzyme preparation and loading, and process strategy were varied. The LCA results show that higher dry matter content leads to a higher environmental impact of the ethanol production, but this can be compensated by reducing the impact of enzyme production and use, and by polyethylene glycol addition at high dry matter content. The results also show that the renewable and non-renewable energy use resulting from the different process configurations ultimately determine their environmental impact. PMID:25299491

  10. Comment on "Highly relativistic spin-gravity coupling for fermions"

    NASA Astrophysics Data System (ADS)

    Hojman, Sergio A.; Asenjo, Felipe A.

    2016-01-01

    We exhibit difficulties of different sorts which appear when using the Mathisson-Papapetrou equations, in particular in the description of highly relativistic particles presented in R. Plyatsko and M. Fenyk [Phys. Rev. D 91, 064033 (2015), 10.1103/PhysRevD.91.064033]. We compare some results of this theory and of the aforementioned work with the ones obtained using a Lagrangian formulation for massive spinning particles and show that the issues mentioned in the preceding sentence do not appear in the Lagrangian treatment.

  11. Monitoring yeast physiology during very high gravity wort fermentations by frequent analysis of gene expression.

    PubMed

    Rautio, Jari J; Huuskonen, Anne; Vuokko, Heikki; Vidgren, Virve; Londesborough, John

    2007-09-01

    Brewer's yeast experiences constantly changing environmental conditions during wort fermentation. Cells can rapidly adapt to changing surroundings by transcriptional regulation. Changes in genomic expression can indicate the physiological condition of yeast in the brewing process. We monitored, using the transcript analysis with aid of affinity capture (TRAC) method, the expression of some 70 selected genes relevant to wort fermentation at high frequency through 9-10 day fermentations of very high gravity wort (25 degrees P) by an industrial lager strain. Rapid changes in expression occurred during the first hours of fermentations for several genes, e.g. genes involved in maltose metabolism, glycolysis and ergosterol synthesis were strongly upregulated 2-6 h after pitching. By the time yeast growth had stopped (72 h) and total sugars had dropped by about 50%, most selected genes had passed their highest expression levels and total mRNA was less than half the levels during growth. There was an unexpected upregulation of some genes of oxygen-requiring pathways during the final fermentation stages. For five genes, expression of both the Saccharomyces cerevisiae and S. bayanus components of the hybrid lager strain were determined. Expression profiles were either markedly different (ADH1, ERG3) or very similar (MALx1, ILV5, ATF1) between these two components. By frequent analysis of a chosen set of genes, TRAC provided a detailed and dynamic picture of the physiological state of the fermenting yeast. This approach offers a possible way to monitor and optimize the performance of yeast in a complex process environment. PMID:17605133

  12. Proof of concept and performance optimization of high gravity batch type centrifuge for dewatering fine coal

    SciTech Connect

    Smith, L.B.; Durney, T.E. Jr.

    1991-04-23

    Coal Technology Corporation (CTC) believes that the new CTC high gravity, high production, batch type centrifugal dryer technology can play a significant role in improving the product quality as well as costs of operation in coal processing plants. It is further believed that the new centrifugal dryer technology can form an important part in systems used to clean up millions of tons of coal fines in refuse piles and ponds. It is anticipated that the new centrifuge can become an important ancillary to the advanced deep cleaning processes for coal. Because of these convictions, CTC has been engaged in a pioneering research effort into the new art of drying fine clean coal in high gravity, high production, batch type of centrifuge, since 1981. This work has progressed to the point where the new centrifugal dryer technology is nearly ready for commercialization. It promises to provide needed fine coal drying capability at somewhat lower capital costs and at substantially lower operating costs than competitive systems. It also promises to do so with no detrimental effects on either the coal quality or the environment. The primary objective of this project is to prove the concept of a high gravity batch centrifuge for drying coal fines in a commercial coal processing plant environment. The proof of concept tests also include testing with a variety of coals from different regions. A further objective is to optimize the efficiency and the cost effectiveness of the new centrifugal dryer technology. 2 figs., 3 tabs.

  13. Gravity investigations

    SciTech Connect

    Healey, D.L.

    1983-12-31

    A large density contrast exists between the Paleozoic rocks (including the rocks of Climax stock) and less dense, Tertiary volcanic rocks and alluvium. This density contrast ranges widely, and herein for interpretive purposes, is assumed to average 0.85 Mg/m{sup 3} (megagrams per cubic meter). The large density contrast makes the gravity method a useful tool with which to study the interface between these rock types. However, little or no density contrast is discernible between the sedimentary Paleozoic rocks that surround the Climax stock and the intrusive rocks of the stock itself. Therefore the gravity method can not be used to define the configuration of the stock. Gravity highs coincide with outcrops of the dense Paleozoic rocks, and gravity lows overlie less-dense Tertiary volcanic rocks and Quaternary alluvium. The positions of three major faults (Boundary, Yucca, and Butte faults) are defined by steep gravity gradients. West of the Climax stock, the Tippinip fault has juxtaposed Paleozoic rocks of similar density, and consequently, has no expression in the gravity data in that area. The gravity station spacing, across Oak Spring Butte, is not sufficient to adequately define any gravity expression of the Tippinip fault. 18 refs., 5 figs.

  14. A Comparison of Airborne Gravity Data with High Quality Ground Truth over the Kauring Test Range

    NASA Astrophysics Data System (ADS)

    Ferguson, S.

    2013-12-01

    Airborne gravity measurements have been continually improving over the last decade, however direct comparison with ground gravity data has proven to be problematic due largely to inconsistencies in the ground data. There exists now however a test range in Western Australia, the Kauring Airborne Gravity Test Site, which has been very carefully surveyed with land gravimeters (among other measurements) for the purpose of making comparisons between airborne gravimetry and gradiometry results and the ground data. Sander Geophysics Limited (SGL) conducted a fixed-wing high-resolution gravimetric survey over this test site for the Victoria State Department of Primary Industries as part of the CarbonNet Project. The survey was flown using SGL's airborne gravity system, AIRGrav (Airborne Inertially Referenced Gravimeter). The survey area is divided into an approximately 5 Km by 5 Km inner "AGG" area and a surrounding 20 Km by 20 Km "AG" area. The area is gently rolling with elevations ranging from approximately 200 to 400 m. For the SGL survey the AG area was covered by lines flown North-South at a spacing of 200 m with control lines at a 2 Km spacing, while the AGG area was covered by lines flown Northwest-Southeast at a spacing of 50 m. The survey followed a draped elevation model with a target ground clearance of 80 m, and the target ground speed was 45 m/sec. In this presentation, the airborne gravity results will be compared with the ground data, including a comparison of the horizontal components (or deflections of the vertical) obtained from the AIRGrav system with the latest available Australian geoid model. Techniques to combine the horizontal components with the vertical to improve resolution will also be presented.

  15. Fuel alcohol production: Optimization of temperature for efficient very-high-gravity fermentation

    SciTech Connect

    Jones, A.M.; Ingledew, M.M. )

    1994-03-01

    The time required to end ferment wheat mash decreased as the temperature was increased from 17 to 33[degrees]C, but it increased as the concentration of dissolved solids was raised from 14.0 to 36.5 g/100 ml. Ethanol yield was not appreciably affected. Over the range of fermentation temperature tested, the addition of urea accelerated the rate of fermentation, decreased the time required to complete fermentation at all dissolved-solid concentrations, and stimulated the production of slightly more ethanol than was produced by the corresponding unsupplemented control mashes. The optimum temperature for maximum ethanol production in urea-supplemented very-high-gravity wheat mash was 27[degrees]C. These data are important for the industrial assessment of very-high-gravity fermentation technology. 19 refs., 2 figs.

  16. Mass changes at different levels revealed by micro-gravity and deformation measurements at Kilauea Volcano, Hawai'i. (Invited)

    NASA Astrophysics Data System (ADS)

    Bagnardi, M.; Poland, M. P.; Battaglia, M.; Carbone, D.; Baker, S.; Amelung, F.

    2013-12-01

    Using campaign micro-gravity measurements collected at Kilauea Volcano, Hawai'i (United States), between December 2009 and November 2012, we document significant mass variations at the summit of the volcano. These variations produce a maximum residual gravity change of +370 14 ?Gal near the east margin of Halema'uma'u Crater, within Kilauea's summit caldera, where in March 2008 a new eruptive vent opened. This vent has progressively enlarged through several collapses and now forms a 210x160 m elliptical cavity that is currently occupied by a lava lake whose surface fluctuates between 25 and 200 meters below the vent rim. Five micro-gravity surveys were performed using two Scintrex CG-5 gravimeters. Each survey was completed following a double-looping procedure, and each measurement was corrected for earth-tides, ocean loading, and instrument drift. Gravity changes at each station were then corrected for the free-air effect using vertical displacements calculated from combined ascending and descending InSAR measurements. InSAR data are from both the German Space Agency (DLR) TerraSAR-X satellite and the Italian Space Agency (ASI) Cosmo-SkyMed satellite-constellation. The spatial distribution of the gravity changes suggests that they are predominantly caused by the enlargement of the vent and variations in the height of the summit lava lake. The contribution to the gravity measurements caused by changes in lava level within the conduit feeding the lava lake is therefore estimated using a numerical model that takes into account its geometry, as inferred from visual and remotely sensed (LiDAR) observations, and lava height at the time of each gravity survey, determined from thermal camera data. These results can be used to make inferences on the density of the magma filling the lava lake, which we compare to values obtained using independent data from continuous gravimeters located near the campaign stations. Estimates of the lava level effect on the gravity allow us to compensate for it and assess changes measured across Kilauea's summit that may be due to mass variations caused by subsurface magma accumulation or withdrawal. We observe that a positive anomaly (which magnitude varies depending on the density of the material used for the fluid filling the lava lake) is still present after this correction in the 20-month-long period following the March 5-9, 2011, east rift zone (ERZ) fissure eruption. InSAR data spanning the same interval show that these positive changes are associated with uplift of the summit area, which we model as the inflation of a shallow magma reservoir at ~1.5 km depth. The contemporary increase in volume, inferred from the deformation data, and in mass, inferred from the micro-gravity measurement, suggest that, after the 2011 ERZ fissure eruption, magma has been accumulating beneath the summit of Kilauea.

  17. Microstructural variations induced by gravity level during directional solidification of near-eutectic iron-carbon type alloys

    NASA Technical Reports Server (NTRS)

    Stefanescu, Doru M.; Fiske, Michael R.; Curreri, Peter A.

    1986-01-01

    The effects of gravity on the microstructure of directionally solidified near-eutectic cast irons are studied, using a Bridgman-type automatic directional solidification furnace aboard a NASA KC-135 aircraft which flies parabolic arcs and generates alternating periods of low-g (0.01 to 0.001 g, 30 seconds long) and high-g (1.8 g, 1.5 minutes long). Results show a refinement of the interlamellar spacing of the eutectic during low-g processing of metastable Fe-C eutectic alloys. Low-g processing of stable Fe-C-Si eutectic alloys (lamellar or spheroidal graphic) results in a coarsening of the eutectic grain structure. Secondary dendrite arm spacing of austenite increases in low-g and decreases in high-g. The effectiveness of low-gravity in the removal of buoyancy-driven graphite phase segregation is demonstrated.

  18. High-Level Data Races

    NASA Technical Reports Server (NTRS)

    Artho, Cyrille; Havelund, Klaus; Biere, Armin; Koga, Dennis (Technical Monitor)

    2003-01-01

    Data races are a common problem in concurrent and multi-threaded programming. They are hard to detect without proper tool support. Despite the successful application of these tools, experience shows that the notion of data race is not powerful enough to capture certain types of inconsistencies occurring in practice. In this paper we investigate data races on a higher abstraction layer. This enables us to detect inconsistent uses of shared variables, even if no classical race condition occurs. For example, a data structure representing a coordinate pair may have to be treated atomically. By lifting the meaning of a data race to a higher level, such problems can now be covered. The paper defines the concepts view and view consistency to give a notation for this novel kind of property. It describes what kinds of errors can be detected with this new definition, and where its limitations are. It also gives a formal guideline for using data structures in a multi-threading environment.

  19. Bed Topography of Store Glacier and Fjord, Greenland from High-Resolution Gravity Data and Multi-Beam Echo Sounding

    NASA Astrophysics Data System (ADS)

    An, L.; Rignot, E. J.; Muto, A.; Morlighem, M.; Kemp, C.

    2014-12-01

    Store Glacier is a major west Greenland outlet tidewater glacier draining an area of 30,000 square km into Uummannaq Fjord, and flowing at a speed of 4.8 km per year at its terminus. The bed topography of the glacier is poorly known and the fjord bathymetry was partially surveyed for the first time in August 2012. In this study, we present a new approach for the inference of the glacier bed topography, ice thickness and sea floor bathymetry using high-resolution airborne gravity data combined with other data. In August 2012, we acquired a 250 m spacing grid of free-air gravity data at a speed of 50 knots with accuracy at sub-milligal level much higher accuracy than NASA Operation IceBridge (OIB) gravity campaign with approximate 5.2 km resolution at 290 knots flying speed. In August 2012 and 2013, we used multi-beam echo sounding to survey the sea floor bathymetry in front of the glacier, extending to the calving face of the glacier. Inland, we combined radar-derived ice thickness with ice motion vectors to reconstruct the bed topography at a high resolution. Using a 3D inversion of the gravity data, we reconstruct seamless bed topography across the ice front boundary that matches interior data and sea floor bathymetry, and provides information about sediment thickness beneath and in front of the glacier. Comparison of the results with prior maps reveals vast differences. IBCAO3 bathymetry suggests an ice front grounded at sea level while the measured ice front is grounded 550 m below sea level. The seamless topography obtained across the grounding line reveals the presence of a previously unknown sill, which explains why the glacier has been so stable in the last 50 years. The results have important impacts on the interpretation of the glacier stability, and sensitivity to thermal forcing from the ocean and surface melt. This work was conducted at UCI under a contract with the Gordon and Betty More Foundation and with NASA.

  20. A laboratory model of post-Newtonian gravity with high power lasers and 4th generation light sources

    NASA Astrophysics Data System (ADS)

    Gregori, G.; Levy, M. C.; Wadud, M. A.; Crowley, B. J. B.; Bingham, R.

    2016-04-01

    Using the post-Newtonian formalism of gravity, we attempt to calculate the x-ray Thomson scattering cross section of electrons that are accelerated in the field of a high intensity optical laser. We show that our results are consistent with previous calculations, suggesting that the combination of high power laser and 4th generation light sources may become a powerful platform to test models exploring high order corrections to the Newtonian gravity.

  1. High-resolution airborne gravity imaging over James Ross Island (West Antarctica)

    USGS Publications Warehouse

    Jordan, T.A.; Ferraccioli, F.; Jones, P.C.; Smellie, J.L.; Ghidella, M.; Corr, H.; Zakrajsek, A.F.

    2007-01-01

    James Ross Island (JRI) exposes a Miocene-Recent alkaline basaltic volcanic complex that developed in a back-arc, east of the northern Antarctic Peninsula. JRI has been the focus of several geological studies because it provides a window on Neogene magmatic processes and paleoenvironments. However, little is known about its internal structure. New airborne gravity data were collected as part of the first high-resolution aerogeophysical survey flown over the island and reveal a prominent negative Bouguer gravity anomaly over Mt Haddington. This is intriguing as basaltic volcanoes are typically associated with positive Bouguer anomalies, linked to underlying mafic intrusions. The negative Bouguer anomaly may be associated with a hitherto unrecognised low-density sub-surface body, such as a breccia-filled caldera, or a partially molten magma chamber.

  2. Bombay gravity high and eruption of Deccan flood basalts (India) from a shallow secondary plume

    NASA Astrophysics Data System (ADS)

    Negi, J. G.; Agrawal, P. K.; Singh, A. P.; Pandey, O. P.

    1992-06-01

    The western margin of India, especially the area surrounding the gravity high of Bombay, is covered by a thick pile of Deccan flood basalts. The massive eruption is one of the largest continental volcanic events at the Cretaceous/Tertiary biological mass extinction boundary ( 65 Ma ago). The area is characterized by several hidden tectonic features, and their origin and evolution have remained controversial. In the search for magma source structure, attention was focused on an unusual oval-shaped positive gravity anomaly over the Bombay coastal zone. The gravity analysis indicates the presence of two subsurface structures at depths of 4.5 0.5 km and 18 2 km. These depths correspond to the top of the crustal basaltic layer and an upwarped Moho discontinuity, respectively. The positive gravity anomaly in three-dimensional analysis reveals a possible magma conduit structure and the near absence of the granitic layer. The unusually shallow Moho layer coincides with the region of a broad high heat flow anomaly (average heat flow more than 80 mW/m 2). The geophysical signatures from the neighborhood show that the asthenosphere has welled up considerably and is located at a depth of about 40 km. High heat flow and asthenospheric depth estimates suggest melting conditions at very shallow depths. It is suggested that the highly differentiated magma associated with the major eruptive phase of Deccan Traps did not originate at the D'' layer. It is hypothesized that magma was brought to the surface by a major secondary plume at a much shallower depth within the lithosphere and possibly at the crust-mantle boundary, as a consequence of subcrustal erosion and secondary melting caused by the extreme velocity of India during the late Cretaceous and early Tertiary. Substantial melting of the base of the lithosphere due to frictional heating might have resulted in the accumulation of a large quantity of magma below the thinned lithosphere at the pre-existing fracture zone near the continental margin. The presence of a magmatic conduit structure above the Moho, derived from the inversion of gravity data and other tectonic conditions, suggests a possible triggering of the magma reservoir by a large bolide impact ( 10 km diameter) at the Cretaceous/Tertiary boundary near Bombay.

  3. Uncertainties in the mass balances of Greenland and Antarctica reconstructed from monthly GRACE level 2 temporal gravity solutions

    NASA Astrophysics Data System (ADS)

    Schrama, E.

    2012-04-01

    With the availability of monthly GRACE level 2 temporal gravity solutions since 2002 we are able to reconstruct the mass balances of the main ice sheets on earth. The reconstruction procedure of the mass balance graphs is however not trivial and depends on at least four assumptions which are discussed in this paper. The first assumption is that our reconstruction procedure is based on an elastic loading theory, which is applied to the potential coefficients observed by GRACE, whereby we remark that gravity flattening of the Earth (due to coefficient C20) requires us to import knowledge from satellite laser ranging. The second assumption is that there is a glacial isostatic adjustment model that describes the visco-elastic rebound of the Earth due to paleo ice sheet loading. A third assumption is that the degree 1 terms of the temporal gravity solutions follow from present day exchanges of mass on Earth which affect the definition of the geocenter. The third assumption imports knowledge from the geocenter for which different possibilities exist. The fourth assumption is that we can undo the consequence of observing the mass changes on Earth with a band limited system such as GRACE which offers a spatial resolution no better than 300 km. The consequence of all above mentioned steps directly affects the outcome of the reconstructed rates of mass change for Greenland and Antarctica. We will show a comprehensive overview of these steps in an attempt to explain the possible limitations and capabilities of the current GRACE system.

  4. Coal Ash Contains High Levels of Radioactivity

    MedlinePLUS

    ... 154590.html Coal Ash Contains High Levels of Radioactivity: Study End product from coal-fired plants may ... 2015 (HealthDay News) -- Coal ash contains levels of radioactivity that raise concern about the environment and human ...

  5. Accurate Gravities of F, G, and K stars from High Resolution Spectra Without External Constraints

    NASA Astrophysics Data System (ADS)

    Brewer, John M.; Fischer, Debra A.; Basu, Sarbani; Valenti, Jeff A.; Piskunov, Nikolai

    2015-06-01

    We demonstrate a new procedure to derive accurate and precise surface gravities from high resolution spectra without the use of external constraints. Our analysis utilizes Spectroscopy Made Easy with robust spectral line constraints and uses an iterative process to mitigate degeneracies in the fitting process. We adopt an updated radiative transfer code, a new treatment for neutral perturber broadening, a line list with multiple gravity constraints and separate fitting for global stellar properties and abundance determinations. To investigate the sources of temperature dependent trends in determining log {\\mkern 1mu} g noted in previous studies, we obtained Keck HIRES spectra of 42 Kepler asteroseismic stars. In comparison to asteroseismically determined log {\\mkern 1mu} g our spectroscopic analysis has a constant offset of 0.01 dex with a rms scatter of 0.05 dex. We also analyzed 30 spectra which had published surface gravities determined using the a/{{R}*} technique from planetary transits and found a constant offset of 0.06 dex and rms scatter of 0.07 dex. The two samples covered effective temperatures between 5000 and 6700 K with log {\\mkern 1mu} g between 3.7 and 4.6.

  6. Updated f(T) gravity constraints from high-redshift cosmography

    NASA Astrophysics Data System (ADS)

    Piedipalumbo, Ester; Moglie, Enrica Della; Cianci, Roberto

    2015-09-01

    In the last dozen years, a wide and variegated mass of observational data revealed that the universe is now expanding at an accelerated rate. In the absence of a well-based theory to interpret the observations, cosmography provides information about the evolution of the universe from measured distances, only assuming that the geometry can be described by the Friedmann-Lemaitre-Robertson-Walker metric. In this paper, we perform a high-redshift analysis which allows us to put constraints on the cosmographic parameters up to the fifth-order, thus inducing indirect constraints on any gravity theory. Here, we are interested in the so-called teleparallel gravity theory, f(T). Actually, we use the analytical expressions of the present day values of f(T) and its derivatives as functions of the cosmographic parameters to map the cosmography region of confidences into confidence ranges for f(T) and its derivative. Moreover, we show how these can be used to test some teleparallel gravity models without solving the dynamical equations. Our analysis is based on the Union2 Type Ia supernovae (SNIa) data set, a set of 28 measurements of the Hubble parameter, the Hubble diagram constructed from some gamma ray bursts (GRB) luminosity distance indicators and Gaussian priors on the distance from the baryon acoustic oscillations (BAOs) and the Hubble constant h. To perform our statistical analysis and to explore the probability distributions of the cosmographic parameters, we use the Markov chain Monte Carlo (MCMC) method.

  7. High-order discontinuous Galerkin methods for coupled thermoconvective flows under gravity modulation

    NASA Astrophysics Data System (ADS)

    Papanicolaou, N. C.; Aristotelous, A. C.

    2015-10-01

    In this work, we develop a High-Order Symmetric Interior Penalty (SIP) Discontinuous Galerkin (DG) Finite Element Method (FEM) to investigate convective flows in a rectangular cavity subject to both vertical and horizontal temperature gradients. The whole cavity is subject to gravity modulation (g-jitter), simulating a microgravity environment. The sensitivity of the bifurcation problem makes the use of a high-order accurate and efficient technique essential. Our method is validated by solving the plane-parallel flow problem and the results were found to be in good agreement with published results. The numerical method was designed to be easily extendable to even more complex flows.

  8. Probing low-scale quantum gravity with high-energy neutrinos

    SciTech Connect

    Ennadifi, Salah Eddine

    2013-05-15

    Motivated by the quantum structure of space-time at high scales M{sub QG}, we study the propagation behavior of the high-energy neutrino within the quantum gravity effect. We consider the possible induced dispersive effect and derive the resulting vacuum refraction index {eta}{sub vac}(E{sub {nu}}) Asymptotically-Equal-To 1 + E{sub {nu}}{sup 2}/M{sub QG}{sup 2}. Then, by referring to the SN1987A and basing on the recorded neutrino data we approach the corresponding scale M{sub QG} Asymptotically-Equal-To 10{sup 4} GeV.

  9. Research on reaction zone structure of high-press gravity-independent singlet oxygen generator

    NASA Astrophysics Data System (ADS)

    Liu, Yushi; Chen, Wenwu; Wang, Jinglong; Xu, Xiaobo; Liu, Zhendong; Ke, Changchun; Guo, Jingwei; Zhang, Shaoqian; Jin, Yuqi; Sang, Fengting

    2015-02-01

    High press, gravity-independent, singlet oxygen generator (HGSOG) [1] with small reaction zone and high chemical efficiency was designed and fabricated. The mixing, reaction and separation processes happened simultaneously in the reaction zone of HGSOG. The size and the configuration of reaction zone are very important for HGSOG. In this paper, p-? value was calculated to determine the upper limit of the volume of reaction zone. The condition of gas-liquid separation was calculated to determine the lower limit of the volume of reaction zone. The utilization rate of Cl2 achieved 90% and the yield of O2(1?) reached 70%.

  10. High-resolution Gravity Field Models of the Moon Using GRAIL mission Data

    NASA Astrophysics Data System (ADS)

    Lemoine, Frank G.; Goossens, Sander; Sabaka, Terrence J.; Nicholas, Joseph B.; Mazarico, Erwan; Rowlands, David D.; Loomis, Bryant D.; Chinn, Douglas S.; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.

    2015-04-01

    The Gravity Recovery and Interior Laboratory (GRAIL) mission was designed to map the structure of the lunar interior from crust to core and to advance the understanding of the Moon's thermal evolution by producing a high-quality, high-resolution map of the gravitational field of the Moon. GRAIL consisted of two spacecraft, with Ka-band tracking between the two satellites as the single science instrument, with the addition of Earth-based tracking using the Deep Space Network. The science mission was divided into two phases: a primary mission from March 1, 2012 to May 29, 2012, and an extended mission from August 30, 2012 to December 14, 2012. The altitude varied from 3 km to 94 km above the lunar surface during both mission phases. Both the primary and the extended mission data have been processed into global models of the lunar gravity field at NASA/GSFC using the GEODYN software up to 1080 x 1080 in spherical harmonics. In addition to the high-resolution global models, local models have also been developed. Due to varying spacecraft altitude and ground track spacing, the actual resolution of the global models varies geographically. Information beyond the current resolution is still present in the data, as indicated by relatively higher fits in the last part of the extended mission, where the satellites achieved their lowest altitude above lunar surface. Local models of the lunar gravitational field at high resolution were thus estimated to accommodate this signal. Here, we present the current status of GRAIL gravity modeling at NASA/GSFC, for both global and local models. We discuss the methods we used for the processing of the GRAIL data, and evaluate these solutions with respect to the derived power spectra, Bouguer anomalies, and fits with independent data (such as from the low-altitude phase of the Lunar Prospector mission). We also evaluate the prospects for extending the resolution of our current models

  11. Viscosity Measurement of Highly Viscous Liquids Using Drop Coalescence in Low Gravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.; Ethridge, Edwin; Maxwell, Daniel

    1999-01-01

    The method of drop coalescence is being investigated for use as a method for determining the viscosity of highly viscous undercooled liquids. Low gravity environment is necessary in this case to minimize the undesirable effects of body forces and liquid motion in levitated drops. Also, the low gravity environment will allow for investigating large liquid volumes which can lead to much higher accuracy for the viscosity calculations than possible under 1 - g conditions. The drop coalescence method is preferred over the drop oscillation technique since the latter method can only be applied for liquids with vanishingly small viscosities. The technique developed relies on both the highly accurate solution of the Navier-Stokes equations as well as on data from experiments conducted in near zero gravity environment. In the analytical aspect of the method two liquid volumes are brought into contact which will coalesce under the action of surface tension alone. The free surface geometry development as well as its velocity during coalescence which are obtained from numerical computations are compared with an analogous experimental model. The viscosity in the numerical computations is then adjusted to bring into agreement of the experimental results with the calculations. The true liquid viscosity is the one which brings the experiment closest to the calculations. Results are presented for method validation experiments performed recently on board the NASA/KC-135 aircraft. The numerical solution for this validation case was produced using the Boundary Element Method. In these tests the viscosity of a highly viscous liquid, in this case glycerine at room temperature, was determined to high degree of accuracy using the liquid coalescence method. These experiments gave very encouraging results which will be discussed together with plans for implementing the method in a shuttle flight experiment.

  12. Satellite borne gravity gradiometer study

    NASA Technical Reports Server (NTRS)

    Metzger, E.; Jircitano, A.; Affleck, C.

    1976-01-01

    Gravity gradiometry is recognized to be a very difficult instrumentation problem because extremely small differential acceleration levels have to be measured, 0.1 EU corresponds to an acceleration of 10 to the minus 11th power g at two points 1 meter apart. A feasibility model of a gravity gradiometer is being developed for airborne applications using four modified versions of the proven Model VII accelerometers mounted on a slowly rotating fixture. Gravity gradients are being measured to 1.07 EU in a vertical rotation axis orientation. Equally significant are the outstanding operational characteristics such as fast reaction time, low temperature coefficients and high degree of bias stability over long periods of time. The rotating accelerometer gravity gradiometer approach and its present status is discussed and it is the foundation for the orbital gravity gradiometer analyzed. The performance levels achieved in a 1 g environment of the earth and under relatively high seismic disturbances, lend the orbital gravity gradiometer a high confidence level of success.

  13. Proof of concept and performance optimization of high gravity batch type centrifuge for dewatering fine coal

    SciTech Connect

    Smith, L.B.; Durney, T.E. Jr.

    1990-07-24

    Coal Technology Corporation (CTC) believes that the new CTC high gravity, high production, batch type centrifugal dryer technology can play a significant role in improving the product quality as well as costs of operation in coal processing plants. It is further believed that the new centrifugal dryer technology can form an important part in systems used to clean up the millions of tons of coal fines in refuse piles and ponds. It is anticipated that the new centrifuge can become an important ancillary to the advanced deep cleaning processes for coal. Because of these convictions, CTC has been engaged in a pioneering research effort into the new art of drying fine clean coal in high gravity, high production, batch type centrifuges, since 1981. This work has progressed to the point where the new centrifugal dryer technology is nearly ready for commercialization. It promises to provide needed fine coal drying capability at somewhat lower capital costs and at substantially lower operating costs than competitive systems. It also promises to do so with no detrimental effects on either the coal quality or the evironment. The primary objective of this project is to prove the concept in a commercial coal processing plant environment. The proof of concept tests will also include testing with a variety of coals from different regions. A further objective will be to optimize the efficiency and the cost effectiveness of the new centrifugal dryer technology.

  14. High-frequency driven capillary flows speed up the gas-liquid phase transition in zero-gravity conditions.

    PubMed

    Beysens, Daniel; Chatain, Denis; Evesque, Pierre; Garrabos, Yves

    2005-07-15

    Under weightlessness conditions, the phase transition of fluids is driven only by slow capillary flows. We investigate the effect of high-frequency vibrations to reproduce some features of gravity effects and show that such vibrations can greatly modify the phase transition kinetics. The investigation is performed in H2 near its critical point (critical temperature 33 K) where critical slowing down enables the phase transition process to be carefully studied. Gravity effects are compensated in a strong magnetic field gradient. PMID:16090746

  15. A simulation for gravity fine structure recovery from high-low GRAVSAT SST data

    NASA Technical Reports Server (NTRS)

    Estes, R. H.; Lancaster, E. R.

    1976-01-01

    Covariance error analysis techniques were applied to investigate estimation strategies for the high-low SST mission for accurate local recovery of gravitational fine structure, considering the aliasing effects of unsolved for parameters. Surface density blocks of 5 deg x 5 deg and 2 1/2 deg x 2 1/2 deg resolution were utilized to represent the high order geopotential with the drag-free GRAVSAT configured in a nearly circular polar orbit at 250 km. altitude. GEOPAUSE and geosynchronous satellites were considered as high relay spacecraft. It is demonstrated that knowledge of gravitational fine structure can be significantly improved at 5 deg x 5 deg resolution using SST data from a high-low configuration with reasonably accurate orbits for the low GRAVSAT. The gravity fine structure recoverability of the high-low SST mission is compared with the low-low configuration and shown to be superior.

  16. Gravity waves and high-altitude CO2 ice cloud formation in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Yi?it, Erdal; Medvedev, Alexander S.; Hartogh, Paul

    2015-06-01

    We present the first general circulation model simulations that quantify and reproduce patches of extremely cold air required for CO2 condensation and cloud formation in the Martian mesosphere. They are created by subgrid-scale gravity waves (GWs) accounted for in the model with the interactively implemented spectral parameterization. Distributions of GW-induced temperature fluctuations and occurrences of supersaturation conditions are in a good agreement with observations of high-altitude CO2 ice clouds. Our study confirms the key role of GWs in facilitating CO2 cloud formation, discusses their tidal modulation, and predicts clouds at altitudes higher than have been observed to date.

  17. Finite volume numerical scheme for high-resolution gravity field modelling and its parallel implementation

    NASA Astrophysics Data System (ADS)

    Fašková, Z.; Macák, M.; Čunderlík, R.; Mikula, K.

    2012-04-01

    The paper discusses a numerical solution of the geodetic boundary value problem (GBVP) by the finite volume method (FVM). The FVM is a numerical method where numerical flux is conserved from one discretization cell to its neighbour, so it's very appropriate for solving GBVP with the Neumann and the Dirichlet BCs. Our numerical scheme is developed for 3D computational domain above an ellipsoid. It is shown that a refinement of the discretization in height's direction leads to more precise numerical results. In order to achieve high-resolution numerical results, parallel implementations of algorithms using the MPI procedures were developed and computations on parallel computers were successfully performed. This basis includes the splitting of all arrays in meridian's direction, usage of an implementation of the Bi-CGSTAB non-stationary iterative solver instead of the standard SOR and an optimization of communications on parallel computers with the NUMA architecture. This gives us higher speed up in comparison to standard approaches and enables us to develop an efficient tool for high-resolution global or regional gravity field modelling in huge areas. Numerical experiments present global modelling with the resolution comparable with EGM2008 and detailed regional modelling in the Pacific Ocean with the resolution 2x2 arc min. Input gravity disturbances are generated from the DTU10-GRAV gravity field model and the disturbing potential is computed from the GOCE_DIR2 satellite geopotential model up to degree 240. Finally, the obtained disturbing potential is used to evaluate the geopotential on the DTU10 mean sea surface and the achieved mean dynamic topography is compared with the ECCO oceanographic model.

  18. Application of precise altimetry to the study of precise leveling of the sea surface, the Earth's gravity field, and the rotation of the Earth

    NASA Technical Reports Server (NTRS)

    Segawa, J.; Ganeko, Y.; Sasaki, M.; Mori, T.; Ooe, M.; Nakagawa, I.; Ishii, H.; Hagiwara, Y.

    1991-01-01

    Our program includes five research items: (1) determination of a precision geoid and gravity anomaly field; (2) precise leveling and detection of tidal changes of the sea surface and study of the role of the tide in the global energy exchange; (3) oceanic effect on the Earth's rotation and polar motion; (4) geological and geophysical interpretation of the altimetry gravity field; and (5) evaluation of the effectiveness of local tracking of TOPEX/POSEIDON by use of a laser tracker.

  19. Adjusting the Ion Permeability of Polyelectrolyte Multilayers through Layer-by-Layer Assembly under a High Gravity Field.

    PubMed

    Jiang, Chao; Luo, Caijun; Liu, Xiaolin; Shao, Lei; Dong, Youqing; Zhang, Yingwei; Shi, Feng

    2015-05-27

    The layer-by-layer (LbL) assembled multilayer has been widely used as good barrier film or capsule due to the advantages of its flexible tailoring of film permeability and compactness. Although many specific systems have been proposed for film design, developing a versatile strategy to control film compactness remains a challenge. We introduced the simple mechanical energy of a high gravity field to the LbL assembly process to tailor the multilayer permeability through adjusting film compactness. By taking poly(diallyldimethylammonium chloride) (PDDA) and poly{1-4[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl sodium salt} (PAzo) as a model system, we investigated the LbL assembly process under a high gravity field. The results showed that the high gravity field introduced effectively accelerated the multilayer deposition process by 20-fold compared with conventional dipping assembly; the adsorption rate was positively dependent on the rotating speed of the high gravity equipment and the concentration of the building block solutions. More interestingly, the film compactness of the PDDA/PAzo multilayer prepared under the high gravity field increased remarkably with the growing rotational speed of the high gravity equipment, as demonstrated through comparisons of surface morphology, cyclic voltammetry curves, and photoisomerization kinetics of PDDA/PAzo multilayers fabricated through the conventional dipping method and through LbL assembly under a high gravity field, respectively. In this way, we have introduced a simple and versatile external form of mechanical energy into the LbL assembling process to improve film compactness, which should be useful for further applications in controlled ion permeability, anticorrosion, and drug loading. PMID:25951984

  20. Dynamic equilibrium under vibrations of H₂ liquid-vapor interface at various gravity levels.

    PubMed

    Gandikota, G; Chatain, D; Lyubimova, T; Beysens, D

    2014-06-01

    Horizontal vibration applied to the support of a simple pendulum can deviate from the equilibrium position of the pendulum to a nonvertical position. A similar phenomenon is expected when a liquid-vapor interface is subjected to strong horizontal vibration. Beyond a threshold value of vibrational velocity the interface should attain an equilibrium position at an angle to the initial horizontal position. In the present paper experimental investigation of this phenomenon is carried out in a magnetic levitation device to study the effect of the vibration parameters, gravity acceleration, and the liquid-vapor density on the interface position. The results compare well with the theoretical expression derived by Wolf [G. H. Wolf, Z. Phys. B 227, 291 (1969)]. PMID:25019875

  1. The seasonal cycle of gravity wave momentum flux and forcing in the high latitude northern hemisphere mesopause region

    NASA Astrophysics Data System (ADS)

    de Wit, R. J.; Hibbins, R. E.; Espy, P. J.

    2015-05-01

    A new generation all-sky SKiYMET meteor radar, optimized to measure high-frequency gravity wave momentum flux, was installed in Trondheim, Norway (63.4N, 10.5E), and has been providing near-continuous measurements since September 2012. Using the system's first full calendar year of observations the seasonal cycle of gravity wave momentum flux and forcing in the mesopause region is studied. The vertical flux of zonal momentum is observed to change from westward to eastward with increasing altitude in winter, and from eastward to westward in summer. This vertical divergence results in westward gravity wave forcing in winter, and eastward forcing in summer. It is shown that the seasonal cycle in gravity wave momentum flux and forcing can be interpreted in terms of selective filtering of a uniform spectrum of vertically propagating GWs between the surface and the mesopause region.

  2. High-resolution Local Gravity Model of the South Pole of the Moon from GRAIL Extended Mission Data

    NASA Technical Reports Server (NTRS)

    Goossens, Sander Johannes; Sabaka, Terence J.; Nicholas, Joseph B.; Lemoine, Frank G.; Rowlands, David D.; Mazarico, Erwan; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.

    2014-01-01

    We estimated a high-resolution local gravity field model over the south pole of the Moon using data from the Gravity Recovery and Interior Laboratory's extended mission. Our solution consists of adjustments with respect to a global model expressed in spherical harmonics. The adjustments are expressed as gridded gravity anomalies with a resolution of 1/6deg by 1/6deg (equivalent to that of a degree and order 1080 model in spherical harmonics), covering a cap over the south pole with a radius of 40deg. The gravity anomalies have been estimated from a short-arc analysis using only Ka-band range-rate (KBRR) data over the area of interest. We apply a neighbor-smoothing constraint to our solution. Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models.

  3. Effects of Varying Gravity Levels on fNIRS Headgear Performance and Signal Recovery

    NASA Technical Reports Server (NTRS)

    Mackey, Jeffrey R.; Harrivel, Angela R.; Adamovsky, Grigory; Lewandowski, Beth E.; Gotti, Daniel J.; Tin, Padetha; Floyd, Bertram M.

    2013-01-01

    This paper reviews the effects of varying gravitational levels on functional Near-Infrared Spectroscopy (fNIRS) headgear. The fNIRS systems quantify neural activations in the cortex by measuring hemoglobin concentration changes via optical intensity. Such activation measurement allows for the detection of cognitive state, which can be important for emotional stability, human performance and vigilance optimization, and the detection of hazardous operator state. The technique depends on coupling between the fNIRS probe and users skin. Such coupling may be highly susceptible to motion if probe-containing headgear designs are not adequately tested. The lack of reliable and self-applicable headgear robust to the influence of motion artifact currently inhibits its operational use in aerospace environments. Both NASAs Aviation Safety and Human Research Programs are interested in this technology as a method of monitoring cognitive state of pilots and crew.

  4. Ethanol Production from Extruded Thermoplastic Maize Meal by High Gravity Fermentation with Zymomonas mobilis

    PubMed Central

    Peralta-Contreras, Mayeli; Aguilar-Zamarripa, Edna; Pérez-Carrillo, Esther; Escamilla-García, Erandi; Serna-Saldívar, Sergio Othon

    2014-01-01

    A comparative study of extruded and ground maize meals as raw materials for the production of regular (12°P) and high gravity (20°P) worts was devised. Extruded water solubility index (WSI) was higher (9.8 percentage units) and crude fat was lower (2.64 percentage units) compared to ground maize. Free-amino nitrogen compounds (FAN), pH, and glucose were evaluated in regular and high gravity worts produced from ground or extruded maize. Extrusion improved glucose content and ethanol yield. In 20°P mashes, extrusion is enhanced by 2.14% initial glucose compared with regular ground mashes. The 12°P and 20°P extruded treatments averaged 12.2% and 8.4% higher ethanol, respectively, compared to the uncooked counterpart. The 20°P worts fermented with Zymomonas mobilis produced 9.56% more ethanol than the 12°P counterpart. The results show that the combination of extrusion and fermentation of 20°P worts improved ethanol yield per kg flour until 20.93%. This pretreatment stimulates Z. mobilis fermentation efficiency. PMID:25530885

  5. Evaluation of an enhanced gravity-based fine-coal circuit for high-sulfur coal

    SciTech Connect

    Mohanty, M.K.; Samal, A.R.; Palit, A.

    2008-02-15

    One of the main objectives of this study was to evaluate a fine-coal cleaning circuit using an enhanced gravity separator specifically for a high sulfur coal application. The evaluation not only included testing of individual unit operations used for fine-coal classification, cleaning and dewatering, but also included testing of the complete circuit simultaneously. At a scale of nearly 2 t/h, two alternative circuits were evaluated to clean a minus 0.6-mm coal stream utilizing a 150-mm-diameter classifying cyclone, a linear screen having a projected surface area of 0.5 m{sup 2}, an enhanced gravity separator having a bowl diameter of 250 mm and a screen-bowl centrifuge having a bowl diameter of 500 mm. The cleaning and dewatering components of both circuits were the same; however, one circuit used a classifying cyclone whereas the other used a linear screen as the classification device. An industrial size coal spiral was used to clean the 2- x 0.6-mm coal size fraction for each circuit to estimate the performance of a complete fine-coal circuit cleaning a minus 2-mm particle size coal stream. The 'linear screen + enhanced gravity separator + screen-bowl circuit' provided superior sulfur and ash-cleaning performance to the alternative circuit that used a classifying cyclone in place of the linear screen. Based on these test data, it was estimated that the use of the recommended circuit to treat 50 t/h of minus 2-mm size coal having feed ash and sulfur contents of 33.9% and 3.28%, respectively, may produce nearly 28.3 t/h of clean coal with product ash and sulfur contents of 9.15% and 1.61 %, respectively.

  6. High Throughput Fluorescent Screening of Membrane Potential under Variable Gravity Conditions

    NASA Astrophysics Data System (ADS)

    Kohn, F. P. M.

    2013-02-01

    In bilayer and patch-clamp experiments it was shown that the electrophysiological parameters of neuronal cells, as there are ion channel activity, intracellular ion concentrations and membrane potential, respond to gravity changes. Due to technical limitations (e.g. time-consuming manual operations) of electrophysiological techniques the amount of acquired data is limited. Optical techniques as fluorescence and fluorometric measurements can also be used to investigate electrophysiological properties of cells as sensitive fluorescent probes for these properties have been developed. On ground various high-throughput fluorometric systems are commercially available. Such a high throughput system would significantly increase the possible data yield and facilitate a lot of future experiments in micro- and hypergravity research. Therefore a FlexStation® 1 from Molecular Devices, a high-throughput multiwell reader, was adapted to parabolic flight conditions. In a first series of experiments the membrane potential of neuronal cells was investigated to verify the system.

  7. Low Gravity Improves Welds

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Kaukler, William F.; Plaster, Teresa C.

    1993-01-01

    Hardnesses and tensile strengths greater. Welds made under right conditions in low gravity appear superior to those made under high gravity. Conclusion drawn from results of welding experiments conducted during low- and high-gravity-simulating maneuvers of KC-135 airplane. Results have implications not only for welding in outer space but also for repeated rapid welding on Earth or in airplanes under simulated low gravity to obtain unusually strong joints.

  8. Crystallization in High-Level Waste Glasses

    SciTech Connect

    Hrma, Pavel R. ); Dane R Spearing, Gary L Smith, SK Sundaram

    2002-01-01

    This review outlines important aspects of crystallization in HLW glasses, such as equilibrium, nucleation, growth, and dissolution. The impact of crystallization on continuous melters and the chemical durability of high-level waste glass are briefly discussed.

  9. High-density particulate gravity currents and their internal density stratifications

    NASA Astrophysics Data System (ADS)

    Cartigny, Matthieu J. B.; Eggenhuisen, Joris T.; Hansen, Ernst W. M.; Postma, George

    2013-04-01

    High-density particulate gravity currents exhibit internal density stratifications. In the basal part of these stratified flows, high-sediment concentrations cause rheological deviations from the Newtonian turbulent flow that dominates clear water and low density conditions. Previous studies have distinguished different types of basal layers on the basis of concentration dependent differences in grain interactions. Field studies have classically linked crude stratification bands, spaced laminations, and/or abundant internal erosion surfaces to high-density particulate gravity currents. Studies of the deposits of such flows have proposed various mechanisms for this variation in depositional characteristics; however, none of these propositions has been thoroughly tested by experiments or theory. This study presents experiments of high-density turbidity currents (varying in initial sediment concentration between 9-26 vol%) moving quasi steady on an inclined bed surface in a 4 x 0.5 x 0.07 m tank. Three distinct internal flow layers were distinguished on the basis of their observed behaviour as captured by a high-speed camera. Ultrasonic velocity profiler (UVP) probes were used to measure the overall velocity and turbulent intensity profiles of the flows, and the change therein as a result of different stacking patterns of internal flow layers. The relation between maximum velocity, shear stress and equilibrium slope for different types of high-density layers were investigated in the experiments. Velocity and camera data were combined to study the interactions between the different flow layers over time. Small-scale fluctuations (0.2-2 seconds) were observed to have a clear control on the depositional behaviour of the flow. However, the influence of these fluctuations gradually decreased with increasing sediment concentrations as function of the different types of basal flow layers. By combining these observations with theoretical grain size sorting mechanism previous experimental results, the different flow layers were linked to distinct depositional expressions known from the rock record.

  10. Physics of Artificial Gravity

    NASA Technical Reports Server (NTRS)

    Bukley, Angie; Paloski, William; Clement, Gilles

    2006-01-01

    This chapter discusses potential technologies for achieving artificial gravity in a space vehicle. We begin with a series of definitions and a general description of the rotational dynamics behind the forces ultimately exerted on the human body during centrifugation, such as gravity level, gravity gradient, and Coriolis force. Human factors considerations and comfort limits associated with a rotating environment are then discussed. Finally, engineering options for designing space vehicles with artificial gravity are presented.

  11. Gravity wave transmission diagram

    NASA Astrophysics Data System (ADS)

    Tomikawa, Y.

    2015-12-01

    A new method of obtaining power spectral distribution of gravity waves as a function of ground-based horizontal phase speed and propagation direction from airglow observations has recently been proposed. To explain gravity wave power spectrum anisotropy, a new gravity wave transmission diagram was developed in this study. Gravity wave transmissivity depends on the existence of critical and turning levels for waves that are determined by background horizontal wind distributions. Gravity wave transmission diagrams for different horizontal wavelengths in simple background horizontal winds with constant vertical shear indicate that the effects of the turning level reflection are significant and strongly dependent on the horizontal wavelength.

  12. Parallel Processing at the High School Level.

    ERIC Educational Resources Information Center

    Sheary, Kathryn Anne

    This study investigated the ability of high school students to cognitively understand and implement parallel processing. Data indicates that most parallel processing is being taught at the university level. Instructional modules on C, Linux, and the parallel processing language, P4, were designed to show that high school students are highly…

  13. Cineradiographic Analysis of Mouse Postural Response to Alteration of Gravity and Jerk (Gravity Deceleration Rate)

    PubMed Central

    Hasegawa, Katsuya; de Campos, Priscila S.; Zeredo, Jorge L.; Kumei, Yasuhiro

    2014-01-01

    The ability to maintain the body relative to the external environment is important for adaptation to altered gravity. However, the physiological limits for adaptation or the disruption of body orientation are not known. In this study, we analyzed postural changes in mice upon exposure to various low gravities. Male C57BL6/J mice (n = 6) were exposed to various gravity-deceleration conditions by customized parabolic flight-maneuvers targeting the partial-gravity levels of 0.60, 0.30, 0.15 and ? g (<0.001 g). Video recordings of postural responses were analyzed frame-by-frame by high-definition cineradiography and with exact instantaneous values of gravity and jerk. As a result, the coordinated extension of the neck, spine and hindlimbs was observed during the initial phase of gravity deceleration. Joint angles widened to 120%200% of the reference g level, and the magnitude of the thoracic-curvature stretching was correlated with gravity and jerk, i.e., the gravity deceleration rate. A certain range of jerk facilitated mouse skeletal stretching efficiently, and a jerk of ?0.3~?0.4 j (g/s) induced the maximum extension of the thoracic-curvature. The postural response of animals to low gravity may undergo differential regulation by gravity and jerk. PMID:25370191

  14. High-Level Application Framework for LCLS

    SciTech Connect

    Chu, P; Chevtsov, S.; Fairley, D.; Larrieu, C.; Rock, J.; Rogind, D.; White, G.; Zalazny, M.; /SLAC

    2008-04-22

    A framework for high level accelerator application software is being developed for the Linac Coherent Light Source (LCLS). The framework is based on plug-in technology developed by an open source project, Eclipse. Many existing functionalities provided by Eclipse are available to high-level applications written within this framework. The framework also contains static data storage configuration and dynamic data connectivity. Because the framework is Eclipse-based, it is highly compatible with any other Eclipse plug-ins. The entire infrastructure of the software framework will be presented. Planned applications and plug-ins based on the framework are also presented.

  15. Local gravity disturbance estimation from multiple-high-single-low satellite-to-satellite tracking

    NASA Technical Reports Server (NTRS)

    Jekeli, Christopher

    1989-01-01

    The idea of satellite-to-satellite tracking in the high-low mode has received renewed attention in light of the uncertain future of NASA's proposed low-low mission, Geopotential Research Mission (GRM). The principal disadvantage with a high-low system is the increased time interval required to obtain global coverage since the intersatellite visibility is often obscured by Earth. The U.S. Air Force has begun to investigate high-low satellite-to-satellite tracking between the Global Positioning System (GPS) of satellites (high component) and NASA's Space Transportation System (STS), the shuttle (low component). Because the GPS satellites form, or will form, a constellation enabling continuous three-dimensional tracking of a low-altitude orbiter, there will be no data gaps due to lack of intervisibility. Furthermore, all three components of the gravitation vector are estimable at altitude, a given grid of which gives a stronger estimate of gravity on Earth's surface than a similar grid of line-of-sight gravitation components. The proposed Air Force mission is STAGE (Shuttle-GPS Tracking for Anomalous Gravitation Estimation) and is designed for local gravity field determinations since the shuttle will likely not achieve polar orbits. The motivation for STAGE was the feasibility to obtain reasonable accuracies with absolutely minimal cost. Instead of simulating drag-free orbits, STAGE uses direct measurements of the nongravitational forces obtained by an inertial package onboard the shuttle. The sort of accuracies that would be achievable from STAGE vis-a-vis other satellite tracking missions such as GRM and European Space Agency's POPSAT-GRM are analyzed.

  16. GOCE long-wavelength gravity field recovery from high-low satellite-to-satellite-tracking using the acceleration approach

    NASA Astrophysics Data System (ADS)

    Reubelt, T.; Baur, O.; Weigelt, M.; Roth, M.; Sneeuw, N.

    2012-04-01

    The restricted sensitivity of the GOCE (Gravity field and steady-state Ocean Circulation Explorer) gradiometer instrument requires satellite gravity gradiometry to be supplemented by orbit analysis in order to resolve long-wavelength features of the geopotential. In this context, the energy conservation method gained particular interest to exploit GPS-based satellite-to-satellite tracking (SST) information. This method has been adopted within official ESA products. On the other hand, various investigations showed the energy conservation principle to be a sub-optimal choice. For this reason, we propose to estimate the low-frequency part of the gravity field by the acceleration approach, which proved to be an efficient and accurate tool in high-low-SST data analysis of former satellite data. This approach balances the gravitational vector with satellite accelerations by means of Newton's law of motion, and hence is characterized by (second-order) numerical differentiation of the kinematic orbit. However, the application of this method to GOCE-SST data, given with a 1s-sampling, showed that serious problems arise due to strong noise amplification of high frequency noise. In order to mitigate this problem, tailored processing strategies with regard to low-pass filtering, variance-covariance information handling, and robust parameter estimation have been adopted. By comparison of our GIWF (Geodetic Institute (GI), Space Research Institute (Institut fr Weltraumforschung, IWF)) solutions and the official GOCE models with a state-of-the-art gravity field solution derived from GRACE (Gravity Recovery And Climate Experiment), we conclude that the acceleration approach is better suited for GOCE-only gravity field determination as opposed to the energy conservation method. Comparisons with solutions from other algorithms, e.g. the variational approach, show that the acceleration approach is able to estimate gravity fields of similar quality.

  17. Gravity, Time, and Lagrangians

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2010-01-01

    Feynman mentioned to us that he understood a topic in physics if he could explain it to a college freshman, a high school student, or a dinner guest. Here we will discuss two topics that took us a while to get to that level. One is the relationship between gravity and time. The other is the minus sign that appears in the Lagrangian. (Why would one…

  18. Gravity, Time, and Lagrangians

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2010-01-01

    Feynman mentioned to us that he understood a topic in physics if he could explain it to a college freshman, a high school student, or a dinner guest. Here we will discuss two topics that took us a while to get to that level. One is the relationship between gravity and time. The other is the minus sign that appears in the Lagrangian. (Why would one

  19. High level performance estimate of relational queries

    SciTech Connect

    Wong, H.K.T.

    1980-08-01

    Performance estimate of queries is a necessary part of any efficient database design methodology. A high-level performance estimator for relational queries is presented which is different from conventional evaluators such as SYSTEM R (Selinger, Proc. SIGMOD 79) in that performance is predicted without the details of the low-level constructs such as links and indices. Rather, abstractions and reasonable assumptions of these low-level constructs are used in a set of formulas to estimate the performance of a set of queries against a schema. The major results of the paper are the realization and motivation of the need of high-level performance estimators of this kind, and a fast way to estimate the cost of N-way joins. The second result is interesting in that the algorithm for N-way joins is found to be similar to matrix multiplication optimization, with straightforward extensions.

  20. Case hardenability at high carbon levels

    SciTech Connect

    Walton, H.W.

    1995-02-01

    Loss of hardenability in the case was thought to be responsible for a lower than specified hardness found on a large carburized bushing. Pseudo Jominy testing on several high hardenability carburizing grades confirmed that hardenability fade was present at carbon levels above 0.65% and particularly for those steels containing molybdenum. Analysis of previous work provided a formula for calculating Jominy hardenability at various carbon levels. Again the results confirmed that the loss of hardenability was more severe in steels containing molybdenum.

  1. Future high sea levels in south Sweden

    SciTech Connect

    Blomgren, S.H.; Hanson, H.

    1997-12-31

    An estimation of future mean high water levels in Oeresund and the southwest Baltic Sea is presented together with a discussion of probable consequences for Falsterbo Peninsula, a trumpet-shaped sandy formation of some 25 km{sup 2} size situated in the very southwest corner of Sweden. A literature review coupled with sea-level measurements and observations made in the area every four hours since October 1945 are given and comprise the base for the present analysis.

  2. High-level waste processing and disposal

    NASA Astrophysics Data System (ADS)

    Crandall, J. L.; Drause, H.; Sombret, C.; Uematsu, K.

    The national high level waste disposal plans for France, the Federal Republic of Germany, Japan, and the United States are covered. Three conclusions are reached. The first conclusion is that an excellent technology already exists for high level waste disposal. With appropriate packaging, spent fuel seems to be an acceptable waste form. Borosilicate glass reprocessing waste forms are well understood, in production in France, and scheduled for production in the next few years in a number of other countries. For final disposal, a number of candidate geological repository sites have been identified and several demonstration sites opened. The second conclusion is that adequate financing and a legal basis for waste disposal are in place in most countries. Costs of high level waste disposal will probably and about 5 to 10% to the costs of nuclear electric power. Third conclusion is less optimistic.

  3. A Software Architecture for High Level Applications

    SciTech Connect

    Shen,G.

    2009-05-04

    A modular software platform for high level applications is under development at the National Synchrotron Light Source II project. This platform is based on client-server architecture, and the components of high level applications on this platform will be modular and distributed, and therefore reusable. An online model server is indispensable for model based control. Different accelerator facilities have different requirements for the online simulation. To supply various accelerator simulators, a set of narrow and general application programming interfaces is developed based on Tracy-3 and Elegant. This paper describes the system architecture for the modular high level applications, the design of narrow and general application programming interface for an online model server, and the prototype of online model server.

  4. The effects of shrinkage flow and gravity level on the onset of convection during vertical directional dendritic solidification of NH4Cl-H2O

    NASA Technical Reports Server (NTRS)

    Hopkins, J. A.; Mccay, T. D.; Mccay, M. H.

    1993-01-01

    A numerical investigation of the conditions influencing the onset of convection during Bridgman vertical directional solidification of NH4Cl- 72 wt percent H2O has been made using a linear stability model. The effects of shrinkage flow and gravity level on the transition from diffusion-dominated to convection-dominated solidification are shown to be significant. Both shrinkage flow opposite the direction of growth and increased gravity levels tend to decrease the stability limits defining the onset of convection for the solidifying NH4Cl-H2O system.

  5. Physiological characterization of brewer's yeast in high-gravity beer fermentations with glucose or maltose syrups as adjuncts.

    PubMed

    Piddocke, Maya P; Kreisz, Stefan; Heldt-Hansen, Hans Peter; Nielsen, Kristian Fog; Olsson, Lisbeth

    2009-09-01

    High-gravity brewing, which can decrease production costs by increasing brewery yields, has become an attractive alternative to traditional brewing methods. However, as higher sugar concentration is required, the yeast is exposed to various stresses during fermentation. We evaluated the influence of high-gravity brewing on the fermentation performance of the brewer's yeast under model brewing conditions. The lager brewer's strain Weihenstephan 34/70 strain was characterized at three different gravities by adding either glucose or maltose syrups to the basic wort. We observed that increased gravity resulted in a lower specific growth rate, a longer lag phase before initiation of ethanol production, incomplete sugar utilization, and an increase in the concentrations of ethyl acetate and isoamyl acetate in the final beer. Increasing the gravity by adding maltose syrup as opposed to glucose syrup resulted in more balanced fermentation performance in terms of higher cell numbers, respectively, higher wort fermentability and a more favorable flavor profile of the final beer. Our study underlines the effects of the various stress factors on brewer's yeast metabolism and the influence of the type of sugar syrups on the fermentation performance and the flavor profile of the final beer. PMID:19343343

  6. High-resolution local gravity model of the south pole of the Moon from GRAIL extended mission data

    PubMed Central

    Goossens, Sander; Sabaka, Terence J; Nicholas, Joseph B; Lemoine, Frank G; Rowlands, David D; Mazarico, Erwan; Neumann, Gregory A; Smith, David E; Zuber, Maria T

    2014-01-01

    We estimated a high-resolution local gravity field model over the south pole of the Moon using data from the Gravity Recovery and Interior Laboratory's extended mission. Our solution consists of adjustments with respect to a global model expressed in spherical harmonics. The adjustments are expressed as gridded gravity anomalies with a resolution of 1/6° by 1/6° (equivalent to that of a degree and order 1080 model in spherical harmonics), covering a cap over the south pole with a radius of 40°. The gravity anomalies have been estimated from a short-arc analysis using only Ka-band range-rate (KBRR) data over the area of interest. We apply a neighbor-smoothing constraint to our solution. Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models. Key Points We present a high-resolution gravity model of the south pole of the Moon Improved correlations with topography to higher degrees than global models Improved fits to the data and reduced striping that is present in global models PMID:26074637

  7. Simultaneous dewatering and reconstitution in a high-gravity solid-bowl centrifuge

    SciTech Connect

    Wen, W.W.; Gray, M.L.; Killmeyer, R.P.; Finseth, D.H.

    1994-12-31

    The Pittsburgh Energy Technology Center has developed a dewatering and reconstitution process in which bitumen emulsion is added to a fine clean coal slurry ahead of the dewatering device. The process simultaneously improves dewatering efficiency and reduces dustiness of the fine coal product during subsequent handling. This paper describes the test results from dewatering and reconstitution of fine coal in a 500 lb. per hour continuous bench scale high-gravity solid-bowl centrifuge in PETC`s Coal Preparation Process Research Facility. Test results will be evaluated in terms of type and dosage of emulsion, product moisture and strength, and product handling and dust reduction efficiency. A preliminary cost analysis will also be included.

  8. High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models

    NASA Technical Reports Server (NTRS)

    Stecker, Floyd W.

    2011-01-01

    High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10-35 m. I will discuss here the possible signatures of Lorentz invariance violation (LIV) from observations of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations ofthe spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) to the amount of LIV at a proton Lorentz factor of -2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space based detection techniques to improve searches for LIV in the future.

  9. Effect of Coriolis force on flow instabilities during solidification of alloys in high gravity

    NASA Astrophysics Data System (ADS)

    Okhuysen, B. S.; Riahi, D. N.

    2001-11-01

    During the solidification of an alloy,convective instabilities induced by solutal gradients may lead to columns of fluid flow in the mushy layer(chimneys).Chimneys convection may lead to the formation of imperfections such as freckles in the resulting solid.Since freckles reduce the quality of the solid material,it is desirable to suppress the modes of convection that lead to chimney formation.Effect of Coriolis force on the solidifying alloys is investigated under a high gravity condition.A linear stability analysis of the flow instabilities of the liquid and mushy regions is performed ,and the neutral stability results are determined computationally for different values of the parameters.Non-trivial effects of the Coriolis force on the most critical convective modes, the resulting flow structure and on the solid fraction and chimney formation within the mushy zone are discussed.

  10. Propagation and Breaking at High Altitudes of Gravity Waves Excited by Tropospheric Forcing

    NASA Technical Reports Server (NTRS)

    Prusa, Joseph M.; Smolarkiewicz, Piotr K.; Garcia, Rolando R.

    1996-01-01

    An anelastic approximation is used with a time-variable coordinate transformation to formulate a two-dimensional numerical model that describes the evolution of gravity waves. The model is solved using a semi-Lagrangian method with monotone (nonoscillatory) interpolation of all advected fields. The time-variable transformation is used to generate disturbances at the lower boundary that approximate the effect of a traveling line of thunderstorms (a squall line) or of flow over a broad topographic obstacle. The vertical propagation and breaking of the gravity wave field (under conditions typical of summer solstice) is illustrated for each of these cases. It is shown that the wave field at high altitudes is dominated by a single horizontal wavelength; which is not always related simply to the horizontal dimension of the source. The morphology of wave breaking depends on the horizontal wavelength; for sufficiently short waves, breaking involves roughly one half of the wavelength. In common with other studies, it is found that the breaking waves undergo "self-acceleration," such that the zonal-mean intrinsic frequency remains approximately constant in spite of large changes in the background wind. It is also shown that many of the features obtained in the calculations can be understood in terms of linear wave theory. In particular, linear theory provides insights into the wavelength of the waves that break at high altitudes, the onset and evolution of breaking. the horizontal extent of the breaking region and its position relative to the forcing, and the minimum and maximum altitudes where breaking occurs. Wave breaking ceases at the altitude where the background dissipation rate (which in our model is a proxy for molecular diffusion) becomes greater than the rate of dissipation due to wave breaking, This altitude, in effect, the model turbopause, is shown to depend on a relatively small number of parameters that characterize the waves and the background state.

  11. Deep Crustal Seismic Investigation Across the Silkeborg Gravity High, Central Denmark

    NASA Astrophysics Data System (ADS)

    Sandrin, A.; Thybo, H.; Nielsen, L.; Lyngsie, S. B.; Keller, G. R.

    2004-12-01

    We recently completed a seismic refraction study across northwestern Denmark (the Jutland Peninsula) as part of our efforts to understand the origin and evolution of the Danish Basin. We were testing the hypothesis that the origin of the Mesozoic sedimentary basins in Denmark is related to extensional regimes and intensive magmatic activity during the Carboniferous and early Permian. Potential field data and existing seismic studies indicate that a large batholith is present within the lower crust below the Silkeborg Gravity High (Central Jutland). The goal of project ESTRID (Explosion Seismic Transect across a Rift In Denmark) is to define the shape and size of this batholith. Our main profile (more 140 km long) was laid out along the strike direction of the Silkeborg anomaly. Around 240 Texan instruments were deployed on this profile and ca. 150 more instruments where deployed in arcuate fan geometries, whose centres of curvature were located at the two extreme shotpoints on each end of the profile. These two shots were detonated in water, in the North Sea (shot 1) and in the Arhus Bay (shot 6). Additionally, 4 shots were fired at regular distances along the main profile. Preliminary analysis with seismic tomography locates the top of the crystalline crust at approximately 9 to 11 km depth, below a thick package of sedimentary rocks of Mesozoic and Palaeozoic age. This result is also confirmed by 1D modelling of the data. The tomographic study also defines the extension and depth to the top (ca. 12 km) of the supposed batholith and the depth to the Moho (ca. 30 km). The PmP (Moho reflection) signal is clearly identified along most of the profile, but not in a ca. 30 km long window at the centre of the gravity high. The Pn (diving waves in the upper mantle) is recognizable at the end of the profile. The reflection from the Moho shows a ringing which is interpreted as indicating a layered structure in the lower crust.

  12. Terrestrial Gravity Fluctuations

    NASA Astrophysics Data System (ADS)

    Harms, Jan

    2015-12-01

    Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10^-23 Hz^-1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of terrestrial gravity fluctuations will have great impact on the future development of GW detectors and high-precision gravimetry in general, and many open questions need to be answered still as emphasized in this article.

  13. Updated Hungarian Gravity Field Solution Based on Fifth Generation GOCE Gravity Field Models

    NASA Astrophysics Data System (ADS)

    Toth, Gyula; Foldvary, Lorant

    2015-03-01

    With the completion of the ESA's GOCE satellite's mission fifth generation gravity field models are available from the ESA's GOCE High Processing Facility. Our contribution is an updated gravity field solution for Hungary using the latest DIR R05 GOCE gravity field model. The solution methodology is least squares gravity field parameter estimation using Spherical Radial Base Functions (SRBF). Regional datasets include deflections of the vertical (DOV), gravity anomalies and quasigeoid heights by GPS/levelling. The GOCE DIR R05 model has been combined with the EGM20008 model and has been evaluated in comparison with the EGM2008 and EIGEN-6C3stat models to assess the performance of our regional gravity field solution.

  14. Acceleration levels on board the Space Station and a tethered elevator for micro and variable-gravity applications

    NASA Technical Reports Server (NTRS)

    Lorenzini, E. C.; Cosmo, M.; Vetrella, S.; Moccia, A.

    1988-01-01

    This paper investigates the dynamics and acceleration levels of a new tethered system for micro and variable-gravity applications. The system consists of two platforms tethered on opposite sides to the Space Station. A fourth platform, the elevator, is placed in between the Space Station and the upper platform. Variable-g levels on board the elevator are obtained by moving this facility along the upper tether, while micro-g experiments are carried out on board the Space Station. By controlling the length of the lower tether the position of the system CM can be maintained on board the Space Station despite variations of the station's distribution of mass. The paper illustrates the mathematical model, the environmental perturbations and the control techniques which have been adopted for the simulation and control of the system dynamics. Two sets of results from two different simulation runs are shown. The first set shows the system dynamics and the acceleration spectra on board the Space Station and the elevator during station-keeping. The second set of results demonstrates the capability of the elevator to attain a preselected g-level.

  15. PAIRWISE BLENDING OF HIGH LEVEL WASTE (HLW)

    SciTech Connect

    CERTA, P.J.

    2006-02-22

    The primary objective of this study is to demonstrate a mission scenario that uses pairwise and incidental blending of high level waste (HLW) to reduce the total mass of HLW glass. Secondary objectives include understanding how recent refinements to the tank waste inventory and solubility assumptions affect the mass of HLW glass and how logistical constraints may affect the efficacy of HLW blending.

  16. High-level radioactive wastes. Supplement 1

    SciTech Connect

    McLaren, L.H.

    1984-09-01

    This bibliography contains information on high-level radioactive wastes included in the Department of Energy's Energy Data Base from August 1982 through December 1983. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. 1452 citations.

  17. Do we understand high-level vision?

    PubMed

    Cox, David Daniel

    2014-04-01

    'High-level' vision lacks a single, agreed upon definition, but it might usefully be defined as those stages of visual processing that transition from analyzing local image structure to analyzing structure of the external world that produced those images. Much work in the last several decades has focused on object recognition as a framing problem for the study of high-level visual cortex, and much progress has been made in this direction. This approach presumes that the operational goal of the visual system is to read-out the identity of an object (or objects) in a scene, in spite of variation in the position, size, lighting and the presence of other nearby objects. However, while object recognition as a operational framing of high-level is intuitive appealing, it is by no means the only task that visual cortex might do, and the study of object recognition is beset by challenges in building stimulus sets that adequately sample the infinite space of possible stimuli. Here I review the successes and limitations of this work, and ask whether we should reframe our approaches to understanding high-level vision. PMID:24552691

  18. Comparison of various isostatic marine gravity disturbances

    NASA Astrophysics Data System (ADS)

    Tenzer, Robert; Bagherbandi, Mohammad; Sjöberg, Lars E.

    2015-08-01

    We present and compare four types of the isostatic gravity disturbances compiled at sea level over the world oceans and marginal seas. These isostatic gravity disturbances are computed by applying the Airy-Heiskanen (AH), Pratt-Hayford (PH) and Vening Meinesz-Moritz (VMM) isostatic models. In addition, we compute the complete crust-stripped (CCS) isostatic gravity disturbances which are defined based on a principle of minimizing their spatial correlation with the Moho geometry. We demonstrate that each applied compensation scheme yields a distinctive spatial pattern in the resulting isostatic marine gravity field. The AH isostatic gravity disturbances provide the smoothest gravity field (by means of their standard deviation). The AH and VMM isostatic gravity disturbances have very similar spatial patterns due to the fact that the same isostatic principle is applied in both these definitions expect for assuming a local (in the former) instead of a global (in the latter) compensation mechanism. The PH isostatic gravity disturbances are highly spatially correlated with the ocean-floor relief. The CCS isostatic gravity disturbances reveal a signature of the ocean-floor spreading characterized by an increasing density of the oceanic lithosphere with age.

  19. Aeromagrnetic study of the midcontinent gravity high of central United States

    USGS Publications Warehouse

    King, Elizabeth R.; Zietz, Isidore

    1971-01-01

    A composite map of detailed aeromagnetic surveys over the midcontinent gravity high provides coverage of the 600-mi-long buried belt of mafic rocks of the Keweenawan Series from their outcrop localities in Minnesota and Wisconsin through Iowa and Nebraska. A map of the subsurface extent of the mafic rocks, based on the intricate magnetic patterns, shows that the rocks form a long, semicontinuous block, averaging 40 mi wide and consisting mainly of a sequence of layered flows. This sequence is probably fault-bounded and has been tilted up along the margins, where the linearity of the anomalies indicates steeper dips. The associated clastic rocks, indicated by a smoother magnetic pattern, occur in basins along both sides of the mafic belt and in grabens and a series of axial basins on the upper surface of the block. The well-defined outliers of flows marginal to the main block and the truncation of some of the outermost flow units along a diagonal boundary striking at an angle to them suggest that the present boundaries of the block are postdepositional structural features. The basins and the edges of the block appear to have controlled later, largely vertical movement in the overlying Paleozoic and younger sedimentary cover. Calculated models based on coincident magnetic and detailed gravity profiles along typical cross sections of the midcontinent gravity high show that the block of mafic rocks is steep-sided and as much as several miles thick. The free-air gravity anomaly, which consists of a large positive maximum flanked by minima, averages very close to zero, indicating that this major crustal feature is regionally compensated, although locally each of its components shows a large departure from equilibrium. Remanent magnetization is a primary factor in the interpretation of the magnetic data. Magnetic property studies of Keweenawan mafic rocks in the Lake Superior region show that remanent magnetization may be five times the magnetization induced by the present Earth's field and differs from it radically in direction. This magnetization was acquired before the flows were tilted into their present positions. A computed magnetic profile shows that a trough of flows with such a magnetization and inward-dipping limbs can account for the observed persistent lows along the western edge of the block, the relatively low magnetic values along the axis of the block, and the large positive anomaly along the eastern side of the block. Flows as much as 1 mi thick near the base of the sequence have a remanent magnetization with a nearly opposite polarity. This reverse polarity has been measured on both sides of Lake Superior and is probably also present farther south, particularly in Iowa where the outer units of the block in an area north of Des Moines give rise to a prominent magnetic low. The axis of this long belt of Keweenawan mafic rocks cuts discordantly through the prevailing east-west-trending fabric of the older Precambrian terrane from southern Kansas to Lake Superior. This belt has several major left-lateral offsets, one of which produces a complete hiatus in the vicinity of the 40th parallel where an east-west transcontinental rift or fracture zone has been proposed. The axial basins of clastic rocks are outlined by linear magnetic anomalies and show a concordant relation to the structure of the mafic flows. These basins are oriented at an angle to the main axis, suggesting that the entire feature originated as a major rift composed of a series of short, linear, en echelon segments with offsets similar to the transform faults characterizing the present mid-ocean rift system. This midcontinent rift may well have been part of a Keweenawan global rift system with initial offsets consisting of transform faults along pre-existing fractures, but apparently it never fully developed laterally into an ocean basin, and the upwelling mafic material was localized along a relatively narrow belt.

  20. Aeromagnetic study of the midcontinent gravity high of central United States

    USGS Publications Warehouse

    King, Elizabeth R.; Zietz, Isidore

    1971-01-01

    A composite map of detailed aeromagnetic surveys over the midcontinent gravity high provides coverage of the 600-mi-long buried belt of mafic rocks of the Keweenawan Series from their outcrop localities in Minnesota and Wisconsin through Iowa and Nebraska. A map of the subsurface extent of the mafic rocks, based on the intricate magnetic patterns, shows that the rocks form a long, semicontinuous block, averaging 40 mi wide and consisting mainly of a sequence of layered flows. This sequence is probably fault-bounded and has been tilted up along the margins, where the linearity of the anomalies indicates steeper dips. The associated clastic rocks, indicated by a smoother magnetic pattern, occur in basins along both sides of the mafic belt and in grabens and a series of axial basins on the upper surface of the block. The well-defined outliers of flows marginal to the main block and the truncation of some of the outermost flow units along a diagonal boundary striking at an angle to them suggest that the present boundaries of the block are postdepositional structural features. The basins and the edges of the block appear to have controlled later, largely vertical movement in the overlying Paleozoic and younger sedimentary cover. Calculated models based on coincident magnetic and detailed gravity profiles along typical cross sections of the midcontinent gravity high show that the block of mafic rocks is steep-sided and as much as several miles thick. The free-air gravity anomaly, which consists of a large positive maximum flanked by minima, averages very close to zero, indicating that this major crustal feature is regionally compensated, although locally each of its components shows a large departure from equilibrium. Remanent magnetization is a primary factor in the interpretation of the magnetic data. Magnetic property studies of Keweenawan mafic rocks in the Lake Superior region show that remanent magnetization may be five times the magnetization induced by the present Earth's field and differs from it radically in direction. This magnetization was acquired before the flows were tilted into their present positions. A computed magnetic profile shows that a trough of flows with such a magnetization and inward-dipping limbs can account for the observed persistent lows along the western edge of the block, the relatively low magnetic values along the axis of the block, and the large positive anomaly along the eastern side of the block. Flows as much as 1 mi thick near the base of the sequence have a remanent magnetization with a nearly opposite polarity. This reverse polarity has been measured on both sides of Lake Superior and is probably also present farther south, particularly in Iowa where the outer units of the block in an area north of Des Moines give rise to a prominent magnetic low. The axis of this long belt of Keweenawan mafic rocks cuts discordantly through the prevailing east-west-trending fabric of the older Precambrian terrane from southern Kansas to Lake Superior. This belt has several major left-lateral offsets, one of which produces a complete hiatus in the vicinity of the 40th parallel where an east-west transcontinental rift or fracture zone has been proposed. The axial basins of clastic rocks are outlined by linear magnetic anomalies and show a concordant relation to the structure of the mafic flows. These basins are oriented at an angle to the main axis, suggesting that the entire feature originated as a major rift composed of a series of short, linear, en echelon segments with offsets similar to the transform faults characterizing the present mid-ocean rift system. This midcontinent rift may well have been part of a Keweenawan global rift system with initial offsets consisting of transform faults along pre-existing fractures, but apparently it never fully developed laterally into an ocean basin, and the upwelling mafic material was localized along a relatively narrow belt.

  1. Features of Propagation of the Acoustic-Gravity Waves Generated by High-Power Periodic Radiation

    NASA Astrophysics Data System (ADS)

    Chernogor, L. F.; Frolov, V. L.

    2013-09-01

    We present the results of the bandpass filtering of temporal variations of the Doppler frequency shift of radio signals from a vertical-sounding Doppler radar located near the city of Kharkov when the ionosphere was heated by high-power periodic (with 10 and 15-min periods) radiation from the Sura facility. The filtering was done in the ranges of periods that are close to the acoustic cutoff period and the BruntVisl period (4-6, 8-12, and 13-17 min). Oscillations with periods of 4-6 min and amplitudes of 50-100 mHz were not recorded in fact. Oscillations with periods of 8-12 and 13-17 min and amplitudes of 60-100 mHz were detected in almost all the sessions. In the former and the latter oscillations, the time of delay with respect to the heater switch-on was close to 100 min and about 40-50 min, respectively. These values correspond to group propagation velocities of about 160 and 320-400 m/s. The Doppler shift oscillations were caused by the acoustic-gravity waves which led to periodic variations in the electron number density with a relative amplitude of about 0.1-1.0%. It was demonstrated that the acoustic-gravity waves were not recorded when the effective power of the Sura facility was equal to 50 MW and they were confidently observed when the effective power was increased up to 130 MW. It is shown that the period of the wave processes was determined by the period of the heating-pause cycles, and the duration of the wave trains did not depend on the duration of the series of heating-pause cycles. The data suggest that the generation mechanism of recorded wave disturbances is different from the mechanism proposed in 1970-1990.

  2. High degree gravitational sensitivity from Mars orbiters for the GMM-1 gravity model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Smith, D. E.; Chan, J. C.; Patel, G. B.; Chinn, D. S.

    1994-01-01

    Orbital sensitivity of the gravity field for high degree terms (greater than 30) is analyzed on satellites employed in a Goddard Mars Model GMM-1, complete in spherical harmonics through degree and order 50. The model is obtained from S-band Doppler data on Mariner 9 (M9), Viking Orbiter 1 (VO1), and Viking Orbiter 2 (VO2) spacecraft, which were tracked by the NASA Deep Space Network on seven different highly eccentric orbits. The main sensitivity of the high degree terms is obtained from the VO1 and VO2 low orbits (300 km periapsis altitude), where significant spectral sensitivity is seen for all degrees out through degree 50. The velocity perturbations show a dominant effect at periapsis and significant effects out beyond the semi-latus rectum covering over 180 degrees of the orbital groundtrack for the low altitude orbits. Because of the wideband of periapsis motion covering nearly 180 degrees in w and +39 degrees in latitude coverage, the VO1 300 km periapsis altitude orbit with inclination of 39 degrees gave the dominant sensitivity in the GMM-1 solution for the high degree terms. Although the VO2 low periapsis orbit has a smaller band of periapsis mapping coverage, it strongly complements the VO1 orbit sensitivity for the GMM-1 solution with Doppler tracking coverage over a different inclination of 80 degrees.

  3. Efficient and accurate high-degree spherical harmonic synthesis of gravity field functionals at the Earth's surface using the gradient approach

    NASA Astrophysics Data System (ADS)

    Hirt, Christian

    2012-09-01

    Spherical harmonic synthesis (SHS) of gravity field functionals at the Earth's surface requires the use of heights. The present study investigates the gradient approach as an efficient yet accurate strategy to incorporate height information in SHS at densely spaced multiple points. Taylor series expansions of commonly used functionals quasigeoid heights, gravity disturbances and vertical deflections are formulated, and expressions of their radial derivatives are presented to arbitrary order. Numerical tests show that first-order gradients, as introduced by Rapp (J Geod 71(5):282-289, 1997) for degree 360 models, produce cm- to dm-level RMS approximation errors over rugged terrain when applied with EGM2008 to degree 2190. Instead, higher-order Taylor expansions are recommended that are capable of reducing approximation errors to insignificance for practical applications. Because the height information is separated from the actual synthesis, the gradient approach can be applied along with existing highly efficient SHS routines to compute surface functionals at arbitrarily dense grid points. This confers considerable computational savings (above or well above one order of magnitude) over conventional point-by-point SHS. As an application example, an ultra-high resolution model of surface gravity functionals (EurAlpGM2011) is constructed over the entire European Alps that incorporates height information in the SHS at 12,000,000 surface points. Based on EGM2008 and residual topography data, quasigeoid heights, gravity disturbances and vertical deflections are estimated at ~200m resolution. As a conclusion, the gradient approach is efficient and accurate for high-degree SHS at multiple points at the Earth's surface.

  4. High-altitude gravity waves in the Martian thermosphere observed by MAVEN/NGIMS and modeled by a gravity wave scheme

    NASA Astrophysics Data System (ADS)

    Yi?it, Erdal; England, Scott L.; Liu, Guiping; Medvedev, Alexander S.; Mahaffy, Paul R.; Kuroda, Takeshi; Jakosky, Bruce M.

    2015-11-01

    First high-altitude observations of gravity wave (GW)-induced CO2 density perturbations in the Martian thermosphere retrieved from NASA's Neutral Gas Ion Mass Spectrometer (NGIMS) instrument on board the Mars Atmosphere Volatile EvolutioN (MAVEN) satellite are presented and interpreted using the extended GW parameterization of Yi?it et al. (2008) and the Mars Climate Database as an input. Observed relative density perturbations between 180 and 220 km of 20-40% demonstrate appreciable local time, latitude, and altitude variations. Modeling for the spatiotemporal conditions of the MAVEN observations suggests that GWs can directly propagate from the lower atmosphere to the thermosphere, produce appreciable dynamical effects, and likely contribute to the observed fluctuations. Modeled effects are somewhat smaller than the observed, but their highly variable nature is in qualitative agreement with observations. Possible reasons for discrepancies between modeling and measurements are discussed.

  5. Complete Bouguer gravity map of the Nevada Test Site and vicinity, Nevada

    SciTech Connect

    Healey, D.L.; Harris, R.N.; Ponce, D.A.; Oliver, H.W.

    1987-12-31

    About 15,000 gravity stations were used to create the gravity map. Gravity studies at the Nevada Test Site were undertaken to help locate geologically favorable areas for underground nuclear tests and to help characterize potential high-level nuclear waste storage sites. 48 refs. (TEM)

  6. Python based high-level synthesis compiler

    NASA Astrophysics Data System (ADS)

    Cieszewski, Rados?aw; Pozniak, Krzysztof; Romaniuk, Ryszard

    2014-11-01

    This paper presents a python based High-Level synthesis (HLS) compiler. The compiler interprets an algorithmic description of a desired behavior written in Python and map it to VHDL. FPGA combines many benefits of both software and ASIC implementations. Like software, the mapped circuit is flexible, and can be reconfigured over the lifetime of the system. FPGAs therefore have the potential to achieve far greater performance than software as a result of bypassing the fetch-decode-execute operations of traditional processors, and possibly exploiting a greater level of parallelism. Creating parallel programs implemented in FPGAs is not trivial. This article describes design, implementation and first results of created Python based compiler.

  7. Optical Mass Gauging System for Measuring Liquid Levels in a Reduced Gravity Environment

    NASA Technical Reports Server (NTRS)

    Sullenberger, Ryan M.; Munoz, Wesley M.; Lyon, Matt P.; Vogel, Kenny; Yalin, Azer P.; Korman, Valentin; Polzin, Kurt A.

    2010-01-01

    A compact and rugged fiber-coupled liquid volume sensor designed for flight on a sounding rocket platform is presented. The sensor consists of a Mach-Zehnder interferometer capable of measuring the amount of liquid contained in a tank under any gravitational conditions, including a microgravity environment, by detecting small changes in the index of refraction of the gas contained within a sensing region. By monitoring changes in the interference fringe pattern as the system undergoes a small compression provided by a piston, the ullage volume of a tank can be directly measured allowing for a determination of the liquid volume. To demonstrate the technique, data are acquired using two tanks containing different volumes of liquid, which are representative of the levels of liquid in a tank at different time periods during a mission. The two tanks are independently exposed to the measurement apparatus, allowing for a determination of the liquid level in each. In a controlled, laboratory test of the unit, the system demonstrated a capability of measuring a liquid level in an individual tank of 10.53 mL with a 2% error. The overall random uncertainty for the flight system is higher than that one test, at +/- 1.5 mL.

  8. The Grace Mission: The Challenges of Using Micron-Level Satellite-to-Satellite Ranging to Measure the Earth's Gravity Field

    NASA Technical Reports Server (NTRS)

    Watkins, M.; Bettadpur, S.

    2000-01-01

    The GRACE Mission, to be launched in mid-2001, will provide an unprecedented map of the Earth's gravity field every month. In this paper, we outline the challenges associated with this micron-level satellite-to-satellite ranging, the solutions used by the GRACE project, and the expected science applications of the data.

  9. Validation of GOCE gravity field models using GPS-leveling data and EGM08: a case study in Brazil

    NASA Astrophysics Data System (ADS)

    Ferreira, V. G.; Zhang, Y.; de Freitas, S. R. C.

    2013-09-01

    Validation of geopotential models derived from Gravity field and steady-state Ocean Circulation Explorer (GOCE) observations is a challenging task in regions with less advanced geodetic infrastructure such as Brazil. In order to assess the current performance of these models, 262 GPS-leveling sites, Earth Gravitational Model 2008 (EGM08) and Residual Terrain Model (RTM) are employed. The validation is based on the differences between GPS-leveling and GOCE-derived models. For the former, the spectral content beyond the GOCE-derived models' maximum degree is removed by using EGM08 and RTM. The results indicate that the GOCE-based models: DGM-1S, SPW (Releases 1 and 2), TIM (Releases 1, 2, 3 and 4), and DIR (Releases 2, 3 and 4), at their maximum degrees have a worse performance than EGM08 while DIR-R1 shows an improvement of 11%. Furthermore, from the steepness of the slopes of the root mean square error (RMSE), it is observed that the optimal combination between DIR-R1 and EGM08 occurs at degree 230 (RMSE of 0.201 m). For the satellite-only models, DIR-R3 reduces the RMSE by ~1.4% compared to TIM-R4 at degree 190. These results are important for Brazil where the accuracy of the current geoid model is approximately 0.28 m.

  10. On the Numerical Solution of High-Order Gravity Modes in Rapidly Rotating Stars

    NASA Astrophysics Data System (ADS)

    Clement, Maurice J.

    1996-05-01

    The slowly pulsating B stars and the line-profile variables on the upper main sequence are now believed to involve nonradial gravity modes of high radial order (n > 15) and be driven by the ionization zones of mainly iron group metals. This paper is a progress report on efforts to compute numerically the eigenfunctions of these particular modes, including the effects of rapid rotation. This computational problem is very challenging for several reasons: (i) high radial orders require very small integration stepsizes to achieve acceptable numerical accuracy and stability, (ii) for a given azimuthal symmetry m, rotation couples or mixes components of different latitudinal symmetry l, each having quite different radial orders, and (iii) in the long-period limit (high n), the g-mode spectrum is so ``rich'' (due in part to rotational mixing) that convergence is possible only if the trial eigenfrequency and the trial eigenfunction boundary values are very close to being the correct ones. Moreover, Murphy's Laws apply here in that the modes of greatest observational interest -- the sectorial or l = m ones -- are the most difficult to compute because for a given radial order they have the longest periods and, therefore, lie in the richest part of mode-space. Nevertheless, I have been successful so far in computing sectorial modes up to radial order n ~ 10 and tesseral ones (l > m) up to n ~ 20. Some examples will be presented.

  11. High-Level Waste Melter Review

    SciTech Connect

    Ahearne, J.; Gentilucci, J.; Pye, L. D.; Weber, T.; Woolley, F.; Machara, N. P.; Gerdes, K.; Cooley, C.

    2002-02-26

    The U.S. Department of Energy (DOE) is faced with a massive cleanup task in resolving the legacy of environmental problems from years of manufacturing nuclear weapons. One of the major activities within this task is the treatment and disposal of the extremely large amount of high-level radioactive (HLW) waste stored at the Hanford Site in Richland, Washington. The current planning for the method of choice for accomplishing this task is to vitrify (glassify) this waste for disposal in a geologic repository. This paper describes the results of the DOE-chartered independent review of alternatives for solidification of Hanford HLW that could achieve major cost reductions with reasonable long-term risks, including recommendations on a path forward for advanced melter and waste form material research and development. The potential for improved cost performance was considered to depend largely on increased waste loading (fewer high-level waste canisters for disposal), higher throughput, or decreased vitrification facility size.

  12. High-Level Waste Melter Study Report

    SciTech Connect

    Perez, Joseph M.; Bickford, Dennis F.; Day, Delbert E.; Kim, Dong-Sang; Lambert, Steven L.; Marra, Sharon L.; Peeler, David K.; Strachan, Denis M.; Triplett, Mark B.; Vienna, John D.; Wittman, Richard S.

    2001-07-13

    At the Hanford Site in Richland, Washington, the path to site cleanup involves vitrification of the majority of the wastes that currently reside in large underground tanks. A Joule-heated glass melter is the equipment of choice for vitrifying the high-level fraction of these wastes. Even though this technology has general national and international acceptance, opportunities may exist to improve or change the technology to reduce the enormous cost of accomplishing the mission of site cleanup. Consequently, the U.S. Department of Energy requested the staff of the Tanks Focus Area to review immobilization technologies, waste forms, and modifications to requirements for solidification of the high-level waste fraction at Hanford to determine what aspects could affect cost reductions with reasonable long-term risk. The results of this study are summarized in this report.

  13. Commissioning of the CMS High Level Trigger

    SciTech Connect

    Agostino, Lorenzo; et al.

    2009-08-01

    The CMS experiment will collect data from the proton-proton collisions delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to 14 TeV. The CMS trigger system is designed to cope with unprecedented luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger architecture only employs two trigger levels. The Level-1 trigger is implemented using custom electronics, while the High Level Trigger (HLT) is based on software algorithms running on a large cluster of commercial processors, the Event Filter Farm. We present the major functionalities of the CMS High Level Trigger system as of the starting of LHC beams operations in September 2008. The validation of the HLT system in the online environment with Monte Carlo simulated data and its commissioning during cosmic rays data taking campaigns are discussed in detail. We conclude with the description of the HLT operations with the first circulating LHC beams before the incident occurred the 19th September 2008.

  14. Very high gravity ethanol fermentation by flocculating yeast under redox potential-controlled conditions

    PubMed Central

    2012-01-01

    Background Very high gravity (VHG) fermentation using medium in excess of 250 g/L sugars for more than 15% (v) ethanol can save energy consumption, not only for ethanol distillation, but also for distillage treatment; however, stuck fermentation with prolonged fermentation time and more sugars unfermented is the biggest challenge. Controlling redox potential (ORP) during VHG fermentation benefits biomass accumulation and improvement of yeast cell viability that is affected by osmotic pressure and ethanol inhibition, enhancing ethanol productivity and yield, the most important techno-economic aspect of fuel ethanol production. Results Batch fermentation was performed under different ORP conditions using the flocculating yeast and media containing glucose of 201??3.1, 252??2.9 and 298??3.8 g/L. Compared with ethanol fermentation by non-flocculating yeast, different ORP profiles were observed with the flocculating yeast due to the morphological change associated with the flocculation of yeast cells. When ORP was controlled at ?100 mV, ethanol fermentation with the high gravity (HG) media containing glucose of 201??3.1 and 252??2.9 g/L was completed at 32 and 56 h, respectively, producing 93.0??1.3 and 120.0??1.8 g/L ethanol, correspondingly. In contrast, there were 24.0??0.4 and 17.0??0.3 g/L glucose remained unfermented without ORP control. As high as 131.0??1.8 g/L ethanol was produced at 72 h when ORP was controlled at ?150 mV for the VHG fermentation with medium containing 298??3.8 g/L glucose, since yeast cell viability was improved more significantly. Conclusions No lag phase was observed during ethanol fermentation with the flocculating yeast, and the implementation of ORP control improved ethanol productivity and yield. When ORP was controlled at ?150 mV, more reducing power was available for yeast cells to survive, which in turn improved their viability and VHG ethanol fermentation performance. On the other hand, controlling ORP at ?100 mV stimulated yeast growth and enhanced ethanol production under the HG conditions. Moreover, the ORP profile detected during ethanol fermentation with the flocculating yeast was less fluctuated, indicating that yeast flocculation could attenuate the ORP fluctuation observed during ethanol fermentation with non-flocculating yeast. PMID:22917193

  15. Chiral gravity, log gravity, and extremal CFT

    SciTech Connect

    Maloney, Alexander; Song Wei; Strominger, Andrew

    2010-03-15

    We show that the linearization of all exact solutions of classical chiral gravity around the AdS{sub 3} vacuum have positive energy. Nonchiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity--the theory with logarithmically relaxed boundary conditions--has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic conformal field theories (CFT). Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We formally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.

  16. Optimization of low-cost medium for very high gravity ethanol fermentations by Saccharomyces cerevisiae using statistical experimental designs.

    PubMed

    Pereira, Francisco B; Guimares, Pedro M R; Teixeira, Jos A; Domingues, Luclia

    2010-10-01

    Statistical experimental designs were used to develop a medium based on corn steep liquor (CSL) and other low-cost nutrient sources for high-performance very high gravity (VHG) ethanol fermentations by Saccharomyces cerevisiae. The critical nutrients were initially selected according to a Plackett-Burman design and the optimized medium composition (44.3 g/L CSL; 2.3 g/L urea; 3.8 g/L MgSO?7H?O; 0.03 g/L CuSO?5H?O) for maximum ethanol production by the laboratory strain CEN.PK 113-7D was obtained by response surface methodology, based on a three-level four-factor Box-Behnken design. The optimization process resulted in significantly enhanced final ethanol titre, productivity and yeast viability in batch VHG fermentations (up to 330 g/L glucose) with CEN.PK113-7D and with industrial strain PE-2, which is used for bio-ethanol production in Brazil. Strain PE-2 was able to produce 18.60.5% (v/v) ethanol with a corresponding productivity of 2.40.1g/L/h. This study provides valuable insights into cost-effective nutritional supplementation of industrial fuel ethanol VHG fermentations. PMID:20627715

  17. Performance of the CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Perrotta, Andrea

    2015-12-01

    The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level is the so-called High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increases in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. The increase in the number of interactions per bunch crossing, on average 25 in 2012, and expected to be around 40 in Run II, will be an additional complication. We present here the expected performance of the main triggers that will be used during the 2015 data taking campaign, paying particular attention to the new approaches that have been developed to cope with the challenges of the new run. This includes improvements in HLT electron and photon reconstruction as well as better performing muon triggers. We will also present the performance of the improved tracking and vertexing algorithms, discussing their impact on the b-tagging performance as well as on the jet and missing energy reconstruction.

  18. High precision gravity analysis and hydrological modeling from the Lunar Laser Ranging Observatory at Apache Point, New Mexico

    NASA Astrophysics Data System (ADS)

    Liang, Jiahao

    The NASA-supported Lunar Laser Ranging project (LLR) is located at Apache Point, New Mexico, which strives to precisely measure the orbital distance between the Earth and the Moon in an accuracy of a few millimeters. To archive this objective, LLR project requires precise data on local ground deformation, which is difficult to measure directly. However, the high precision gravity data is the reflection of vertical ground deformation of the Earth, therefore the gravity data is able to contribute to the LLR project. Gravity time series is affected by Earth tides, atmospheric pressure, polar motion, and the most critical effect, local hydrology. In order to isolate pure geodetic variation, these effects must be removed from the data. Thus, the goal of this research is to create models of above effects, especially local hydrology model, in order to isolate the vertical deformation signal. The Earth tides, atmospheric pressure and polar motion effects have been modeled and subtracted from gravity data (2009~2012). The local hydrological model has been created based on the in-situ data, which are rainfall, snowfall and temperature. The correlation coefficient and RMS misfit between the hydrological model and gravity residual (2010~2012) is 0.92 and 1.26 microGal. The instrument drift corrections in 2009 have been reanalyzed after comparing with some global hydrological models. The gravity residual from new corrections showed a correlation coefficient of 0.76 and RMS misfit of 1.25 microGal. The isolated deformation signal was obtained after we subtracted the hydrological effects, and the results can be used for further modeling.

  19. Robust industrial Saccharomyces cerevisiae strains for very high gravity bio-ethanol fermentations.

    PubMed

    Pereira, Francisco B; Guimares, Pedro M R; Teixeira, Jos A; Domingues, Luclia

    2011-08-01

    The application and physiological background of two industrial Saccharomyces cerevisiae strains, isolated from harsh industrial environments, were studied in Very High Gravity (VHG) bio-ethanol fermentations. VHG laboratory fermentations, mimicking industrially relevant conditions, were performed with PE-2 and CA1185 industrial strains and the CEN.PK113-7D laboratory strain. The industrial isolates produced remarkable high ethanol titres (>19%, v/v) and accumulated an increased content of sterols (2 to 5-fold), glycogen (2 to 4-fold) and trehalose (1.1-fold), relatively to laboratory strain. For laboratory and industrial strains, a sharp decrease in the viability and trehalose concentration was observed above 90 g l? and 140 g l? ethanol, respectively. PE-2 and CA1185 industrial strains presented important physiological differences relatively to CEN.PK113-7D strain and showed to be more prepared to cope with VHG stresses. The identification of a critical ethanol concentration above which viability and trehalose concentration decrease significantly is of great importance to guide VHG process engineering strategies. This study contributes to the improvement of VHG processes by identifying yeast isolates and gathering yeast physiological information during the intensified fermentation process, which, besides elucidating important differences between these industrial and laboratory strains, can drive further process optimization. PMID:21543257

  20. Evaluation of theories of complex movement planning in different levels of gravity.

    PubMed

    Tagliabue, M; Pedrocchi, A; Baroni, G; Pedotti, A; Ferrigno, G

    2005-01-01

    Due to high redundancy of degrees of freedom in the human body, we can perform any movement, from the simplest to the most complex, in many different ways. Several studies are still trying to identify the motor strategies that master this redundancy and generate the movements whose characteristics are highly stereotyped. The aim of this work is to build a simulator that is able to evaluate different motor planning hypotheses. The most interesting applications of this tool occur in studies of the motor strategy in microgravity conditions. The comparison between simulated movements and kinematics data recorded both on Earth, and during a 5-month mission on board the Mir station shows that for a complex whole-body movement (such as trunk bending) a single planning criterion cannot explain all movement aspects. However, the simulator allows an understanding of the motor planning adaptation of astronauts. In space, the lack of equilibrium constraint (which on Earth brings about the center of mass control) leads to a new motor strategy that minimizes dynamic interactions with the floor. PMID:15835041

  1. GravityCam: ground-based wide-field high-resolution imaging and high-speed photometry

    NASA Astrophysics Data System (ADS)

    Dominik, Martin; Mackay, Craig; Steele, Iain; Snodgrass, Colin; Hirsch, Michael; Gråe Jørgensen, Uffe; Hundertmark, Markus; Rebolo, Rafael; Horne, Keith; Bridle, Sarah; Sicardy, Bruno; Bramich, Daniel; Alsubai, Khalid

    2015-12-01

    The image blurring by the Earth's atmosphere generally poses a substantial limitation to ground-based observations. While opportunities in space are scarce, lucky imaging can correct over a much larger patch of sky and with much fainter reference stars. We propose the first of a new kind of versatile instruments, "GravityCam", composed of ~100 EMCCDs, that will open up two entirely new windows to ground-based astronomy: (1) wide-field high-resolution imaging, and (2) wide-field high-speed photometry. Potential applications include (a) a gravitational microlensing survey going 4 magnitudes deeper than current efforts, and thereby gaining a factor 100 in mass at the same sensitivity, which means probing down to Lunar mass or even below, (b) extra-solar planet hunting via transits in galactic bulge fields, with high time resolution well-suited for transit timing variation studies, (c) variable stars in crowded fields, with sensitivity to very short periods, (d) asteroseismology with many bright stars in one pointing, (e) serendipitous occultations of stars by small solar system bodies, giving access to the small end of the Kuiper Belt size distribution and potentially leading to the first detection of true Oort cloud objects, while predicted occultations at high time resolution can reveal atmospheres, satellites, or rings, (f) general data mining of the high-speed variable sky (down to 40 ms cadence).

  2. Observing coseismic gravity change from the Japan Tohoku-Oki 2011 earthquake with GOCE gravity gradiometry

    NASA Astrophysics Data System (ADS)

    Fuchs, Martin J.; Bouman, Johannes; Broerse, Taco; Visser, Pieter; Vermeersen, Bert

    2013-10-01

    Japan Tohoku-Oki earthquake (9.0 Mw) of 11 March 2011 has left signatures in the Earth's gravity field that are detectable by data of the Gravity field Recovery and Climate Experiment (GRACE) mission. Because the European Space Agency's (ESA) satellite gravity mission Gravity field and steady-state Ocean Circulation Explorer (GOCE)launched in 2009aims at high spatial resolution, its measurements could complement the GRACE information on coseismic gravity changes, although time-variable gravity was not foreseen as goal of the GOCE mission. We modeled the coseismic earthquake geoid signal and converted this signal to vertical gravity gradients at GOCE satellite altitude. We combined the single gradient observations in a novel way reducing the noise level, required to detect the coseismic gravity change, subtracted a global gravity model, and applied tailored outlier detection to the resulting gradient residuals. Furthermore, the measured gradients were along-track filtered using different gradient bandwidths where in the space domain Gaussian smoothing has been applied. One-year periods before and after earthquake occurrence have been compared with the modeled gradients. The comparison reveals that the earthquake signal is well above the accuracy of the vertical gravity gradients at orbital height. Moreover, the obtained signal from GOCE shows a 1.3 times higher amplitude compared with the modeled signal. Besides the statistical significance of the obtained signal, it has a high spatial correlation of ~0.7 with the forward modeled signal. We conclude therefore that the coseismic gravity change of the Japan Tohoku-Oki earthquake left a statistically significant signal in the GOCE measured gravity gradients.

  3. Analysis of the influence of coupled diffusion on transport in protein crystal growth for different gravity levels.

    PubMed

    Castagnolo, D; Vergara, A; Paduano, L; Sartorio, R; Annunziata, O

    2002-10-01

    Diffusion has a central role in protein crystal growth both in microgravity conditions and on ground. Recently several reports have been focused on the importance to use the generalized Fick's equations in n-component systems where crystals grow. In these equations the total flux of each component is produced by the own concentration gradient (main flow) and by the concentration gradient of the other components (cross-flow) present in the system. However in literature the latter effect is often neglected, and the so-called pseudo-binary approximation is used. Lin et al. (1995) proposed a mathematical model to evaluate the concentration profile of the species present around a growing protein crystal. Although the model is reliable, it suffers of the pseudo-binary approximation (neglecting cross term diffusion coefficients and using binary diffusion coefficients), probably because of the lack of multicomponent diffusion data. The present model is based on the experimental set-up proposed by Lin et al. (1995). Nevertheless we have included the coupled diffusion effects, according to the correct description of the matter transport through the generalized Fick's equations. The crystal growth rate is calculated for different gravity levels. The model has been applied to the ternary lysozyme-NaCl-water and quaternary lysozyme-poly(ethylene glycol) (PEG)-NaCl-water systems using recent diffusion data. PMID:12351876

  4. Assimilation of TOPEX Sea Level Measurements with a Reduced-Gravity, Shallow Water Model of the Tropical Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Fukumori, Ichiro

    1995-01-01

    Sea surface height variability measured by TOPEX is analyzed in the tropical Pacific Ocean by way of assimilation into a wind-driven, reduced-gravity, shallow water model using an approximate Kalman filter and smoother. The analysis results in an optimal fit of the dynamic model to the observations, providing it dynamically consistent interpolation of sea level and estimation of the circulation. Nearly 80% of the expected signal variance is accounted for by the model within 20 deg of the equator, and estimation uncertainty is substantially reduced by the voluminous observation. Notable features resolved by the analysis include seasonal changes associated with the North Equatorial Countercurrent and equatorial Kelvin and Rossby waves. Significant discrepancies are also found between the estimate and TOPEX measurements, especially near the eastern boundary. Improvements in the estimate made by the assimilation are validated by comparisons with independent tide gauge and current meter observations. The employed filter and smoother are based on approximately computed estimation error covariance matrices, utilizing a spatial transformation and an symptotic approximation. The analysis demonstrates the practical utility of a quasi-optimal filter and smoother.

  5. (abstract) Venus Gravity Field

    NASA Technical Reports Server (NTRS)

    Konopliv, A. S.; Sjogren, W. L.

    1995-01-01

    A global gravity field model of Venus to degree and order 75 (5772 spherical harmonic coefficients) has been estimated from Doppler radio tracking of the orbiting spacecraft Pioneer Venus Orbiter (1979-1992) and Magellan (1990-1994). After the successful aerobraking of Magellan, a near circular polar orbit was attained and relatively uniform gravity field resolution (approximately 200 km) was obtained with formal uncertainties of a few milligals. Detailed gravity for several highland features are displayed as gravity contours overlaying colored topography. The positive correlation of typography with gravity is very high being unlike that of the Earth, Moon, and Mars. The amplitudes are Earth-like, but have significantly different gravity-topography ratios for different features. Global gravity, geoid, and isostatic anomaly maps as well as the admittance function are displayed.

  6. The high-level trigger of ALICE

    NASA Astrophysics Data System (ADS)

    Tilsner, H.; Alt, T.; Aurbakken, K.; Grastveit, G.; Helstrup, H.; Lindenstruth, V.; Loizides, C.; Nystrand, J.; Roehrich, D.; Skaali, B.; Steinbeck, T.; Ullaland, K.; Vestbo, A.; Vik, T.

    One of the main tracking detectors of the forthcoming ALICE Experiment at the LHC is a cylindrical Time Projection Chamber (TPC) with an expected data volume of about 75 MByte per event. This data volume, in combination with the presumed maximum bandwidth of 1.2 GByte/s to the mass storage system, would limit the maximum event rate to 20 Hz. In order to achieve higher event rates, online data processing has to be applied. This implies either the detection and read-out of only those events which contain interesting physical signatures or an efficient compression of the data by modeling techniques. In order to cope with the anticipated data rate, massive parallel computing power is required. It will be provided in form of a clustered farm of SMP-nodes, based on off-the-shelf PCs, which are connected with a high bandwidth low overhead network. This High-Level Trigger (HLT) will be able to process a data rate of 25 GByte/s online. The front-end electronics of the individual sub-detectors is connected to the HLT via an optical link and a custom PCI card which is mounted in the clustered PCs. The PCI card is equipped with an FPGA necessary for the implementation of the PCI-bus protocol. Therefore, this FPGA can also be used to assist the host processor with first-level processing. The first-level processing done on the FPGA includes conventional cluster-finding for low multiplicity events and local track finding based on the Hough Transformation of the raw data for high multiplicity events. PACS: 07.05.-t Computers in experimental physics - 07.05.Hd Data acquisition: hardware and software - 29.85.+c Computer data analysis

  7. EAP high-level product architecture

    NASA Astrophysics Data System (ADS)

    Gudlaugsson, T. V.; Mortensen, N. H.; Sarban, R.

    2013-04-01

    EAP technology has the potential to be used in a wide range of applications. This poses the challenge to the EAP component manufacturers to develop components for a wide variety of products. Danfoss Polypower A/S is developing an EAP technology platform, which can form the basis for a variety of EAP technology products while keeping complexity under control. High level product architecture has been developed for the mechanical part of EAP transducers, as the foundation for platform development. A generic description of an EAP transducer forms the core of the high level product architecture. This description breaks down the EAP transducer into organs that perform the functions that may be present in an EAP transducer. A physical instance of an EAP transducer contains a combination of the organs needed to fulfill the task of actuator, sensor, and generation. Alternative principles for each organ allow the function of the EAP transducers to be changed, by basing the EAP transducers on a different combination of organ alternatives. A model providing an overview of the high level product architecture has been developed to support daily development and cooperation across development teams. The platform approach has resulted in the first version of an EAP technology platform, on which multiple EAP products can be based. The contents of the platform have been the result of multi-disciplinary development work at Danfoss PolyPower, as well as collaboration with potential customers and research institutions. Initial results from applying the platform on demonstrator design for potential applications are promising. The scope of the article does not include technical details.

  8. The effects of high level infrasound

    SciTech Connect

    Johnson, D.L.

    1980-02-01

    This paper will attempt to survey the current knowledge on the effects of relative high levels of infrasound on humans. While this conference is concerned mainly about hearing, some discussion of other physiological effects is appropriate. Such discussion also serves to highlight a basic question, 'Is hearing the main concern of infrasound and low frequency exposure, or is there a more sensitive mechanism'. It would be comforting to know that the focal point of this conference is indeed the most important concern. Therefore, besides hearing loss and auditory threshold of infrasonic and low frequency exposure, four other effects will be provided. These are performance, respiration, annoyance, and vibration.

  9. Service Oriented Architecture for High Level Applications

    SciTech Connect

    Chu, Chungming; Chevtsov, Sergei; Wu, Juhao; Shen, Guobao; /Brookhaven

    2012-06-28

    Standalone high level applications often suffer from poor performance and reliability due to lengthy initialization, heavy computation and rapid graphical update. Service-oriented architecture (SOA) is trying to separate the initialization and computation from applications and to distribute such work to various service providers. Heavy computation such as beam tracking will be done periodically on a dedicated server and data will be available to client applications at all time. Industrial standard service architecture can help to improve the performance, reliability and maintainability of the service. Robustness will also be improved by reducing the complexity of individual client applications.

  10. Investigating why recycling gravity harvested algae increases harvestability and productivity in high rate algal ponds.

    PubMed

    Park, J B K; Craggs, R J; Shilton, A N

    2013-09-15

    It has previously been shown that recycling gravity harvested algae promotes Pediastrum boryanum dominance and improves harvestability and biomass production in pilot-scale High Rate Algal Ponds (HRAPs) treating domestic wastewater. In order to confirm the reproducibility of these findings and investigate the mechanisms responsible, this study utilized twelve 20 L outdoor HRAP mesocosms operated with and without algal recycling. It then compared the recycling of separated solid and liquid components of the harvested biomass against un-separated biomass. The work confirmed that algal recycling promoted P. boryanum dominance, improved 1 h-settleability by >20% and increased biomass productivity by >25% compared with controls that had no recycling. With regard to the improved harvestability, of particular interest was that recycling the liquid fraction alone caused a similar improvement in settleability as recycling the solid fraction. This may be due to the presence of extracellular polymeric substances in the liquid fraction. While there are many possible mechanisms that could account for the increased productivity with algal recycling, all but two were systematically eliminated: (i) the mean cell residence time was extended thereby increasing the algal concentration and more fully utilizing the incident sunlight and, (ii) the relative proportions of algal growth stages (which have different specific growth rates) was changed, resulting in a net increase in the overall growth rate of the culture. PMID:23866138

  11. Preparation and characterization of zinc sulfide nanoparticles under high-gravity environment

    SciTech Connect

    Chen Jianfeng; Li Yaling; Wang Yuhong; Yun, Jimmy; Cao Dapeng

    2004-02-02

    Nanosized ZnS particles were prepared under high-gravity environment generated by the rotating packed bed reactor (RPBR) using zinc nitrate solution and hydrogen sulfide gas as raw materials. The effects of experimental conditions such as reactant concentration, reaction temperature, rotating speed of the RPBR and aging time, on the preparation of nanosized ZnS particles were investigated. A set of suitable operating parameters (the aging time of 48 h, concentration of zinc nitrate of 0.1 mol/l, reaction temperature of 45 deg. C and rotating speed of the RPBR of 1500-1800 rotation/min) for the preparation of nanosized ZnS were recommended. Under these optimum conditions, well-dispersed ZnS nanoparticles was obtained. The crystal structure, optical properties, size and morphology of the product were also characterized by XRD, UV-Vis spectrophotometer, and TEM, respectively. Results indicate that the prepared ZnS has a good absorption for light in the wavelength range of 200-330 nm. XRD analysis also shows the prepared ZnS is in a sphalerite crystal phase. The process has great potential of commercialization.

  12. High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models

    NASA Technical Reports Server (NTRS)

    Stecker, Floyd W.

    2012-01-01

    High energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approx.10(exp -35) m. I will discuss the possible signatures of Lorentz invariance violation (LIV) that can be manifested by observing of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) on the fraction of LIV at a Lorentz factor of approx. 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space-based detection techniques to improve searches for LIV in the future. I will also discuss how the LIV formalism casts doubt on the OPERA superluminal neutrino claim.

  13. High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    2011-01-01

    High energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10(exp -35)m. I will discuss the possible signatures of Lorentz invariance violation (LIV) that can be manifested by observing of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and y-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) on the fraction of LIV at a Lorentz factor of approximately 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space-based detection techniques to improve searches for LIV in the future.

  14. Nanohertz frequency determination for the gravity probe B high frequency superconducting quantum interference device signal.

    PubMed

    Salomon, M; Conklin, J W; Kozaczuk, J; Berberian, J E; Keiser, G M; Silbergleit, A S; Worden, P; Santiago, D I

    2011-12-01

    In this paper, we present a method to measure the frequency and the frequency change rate of a digital signal. This method consists of three consecutive algorithms: frequency interpolation, phase differencing, and a third algorithm specifically designed and tested by the authors. The succession of these three algorithms allowed a 5 parts in 10(10) resolution in frequency determination. The algorithm developed by the authors can be applied to a sampled scalar signal such that a model linking the harmonics of its main frequency to the underlying physical phenomenon is available. This method was developed in the framework of the gravity probe B (GP-B) mission. It was applied to the high frequency (HF) component of GP-B's superconducting quantum interference device signal, whose main frequency f(z) is close to the spin frequency of the gyroscopes used in the experiment. A 30 nHz resolution in signal frequency and a 0.1 pHz/s resolution in its decay rate were achieved out of a succession of 1.86 s-long stretches of signal sampled at 2200 Hz. This paper describes the underlying theory of the frequency measurement method as well as its application to GP-B's HF science signal. PMID:22225252

  15. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed.

    PubMed

    Chang, E-E; Pan, Shu-Yuan; Chen, Yi-Hung; Tan, Chung-Sung; Chiang, Pen-Chi

    2012-08-15

    Carbon dioxide (CO(2)) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO(2) sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min(-1) of a pure CO(2) stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate. PMID:22633879

  16. The High Level Data Reduction Library

    NASA Astrophysics Data System (ADS)

    Ballester, P.; Gabasch, A.; Jung, Y.; Modigliani, A.; Taylor, J.; Coccato, L.; Freudling, W.; Neeser, M.; Marchetti, E.

    2015-09-01

    The European Southern Observatory (ESO) provides pipelines to reduce data for most of the instruments at its Very Large telescope (VLT). These pipelines are written as part of the development of VLT instruments, and are used both in the ESO's operational environment and by science users who receive VLT data. All the pipelines are highly specific geared toward instruments. However, experience showed that the independently developed pipelines include significant overlap, duplication and slight variations of similar algorithms. In order to reduce the cost of development, verification and maintenance of ESO pipelines, and at the same time improve the scientific quality of pipelines data products, ESO decided to develop a limited set of versatile high-level scientific functions that are to be used in all future pipelines. The routines are provided by the High-level Data Reduction Library (HDRL). To reach this goal, we first compare several candidate algorithms and verify them during a prototype phase using data sets from several instruments. Once the best algorithm and error model have been chosen, we start a design and implementation phase. The coding of HDRL is done in plain C and using the Common Pipeline Library (CPL) functionality. HDRL adopts consistent function naming conventions and a well defined API to minimise future maintenance costs, implements error propagation, uses pixel quality information, employs OpenMP to take advantage of multi-core processors, and is verified with extensive unit and regression tests. This poster describes the status of the project and the lesson learned during the development of reusable code implementing algorithms of high scientific quality.

  17. GRAIL gravity field determination using the Celestial Mechanics Approach

    NASA Astrophysics Data System (ADS)

    Arnold, Daniel; Bertone, Stefano; Jäggi, Adrian; Beutler, Gerhard; Mervart, Leos

    2015-11-01

    The NASA mission GRAIL (Gravity Recovery and Interior Laboratory) inherited its concept from the GRACE (Gravity Recovery and Climate Experiment) mission to determine the gravity field of the Moon. We present lunar gravity fields based on the data of GRAIL's primary mission phase. Gravity field recovery is realized in the framework of the Celestial Mechanics Approach, using a development version of the Bernese GNSS Software along with Ka-band range-rate data series as observations and the GNI1B positions provided by NASA JPL as pseudo-observations. By comparing our results with the official level-2 GRAIL gravity field models we show that the lunar gravity field can be recovered with a high quality by adapting the Celestial Mechanics Approach, even when using pre-GRAIL gravity field models as a priori fields and when replacing sophisticated models of non-gravitational accelerations by appropriately spaced pseudo-stochastic pulses (i.e., instantaneous velocity changes). We present and evaluate two lunar gravity field solutions up to degree and order 200 - AIUB-GRL200A and AIUB-GRL200B. While the first solution uses no gravity field information beyond degree 200, the second is obtained by using the official GRAIL field GRGM900C up to degree and order 660 as a priori information. This reduces the omission errors and demonstrates the potential quality of our solution if we resolved the gravity field to higher degree.

  18. Adsorption behavior of pesticide methomyl on activated carbon in a high gravity rotating packed bed reactor.

    PubMed

    Chang, Chiung-Fen; Lee, Shu-Chi

    2012-06-01

    High gravity rotating packed bed (HGRPB) reactor possesses the property of high mass transfer rate, which is expected to promote the adsorption rate for the process. In this study, HGRPB has been applied on adsorption removal of methomyl from solution, adopting the adsorbent of activated carbon F400. The influence of operating parameters of HGRPB on mass transfer such as the rotating speed (N(R)), the flow rate of solution (F(L)) and initial concentration of methomyl (C(b0)) were examined. The traditionally internal mass transfer models combined with Freundlich isotherm were used to predict the surface and effective diffusion coefficients. In addition, the results have also been compared with those obtained from the traditional basket stirred batch reactor (BBR). The results showed that the larger values of N(R) and F(L) enhanced the effective intraparticle diffusion and provided more accessible adsorption sites so as to result in lower equilibrium concentration in HGRPB system when compared to SBR system. The results of adsorption kinetics demonstrated that surface and effective diffusions were both significantly greater in HGRPB system instead of BBR system. Furthermore, the values of Bi(S) also manifested less internal mass transfer resistance in HGRPB system. The contribution ratio (R(F)) of the surface to pore diffusion mass transport showed that the larger contribution resulted from the surface diffusion in HGRPB system. Therefore, the results reasonably led to the conclusion that when the HGRPB system applied on the adsorption of methomyl on F400, the lower equilibrium concentration and faster internal mass transfer can be obtained so as to highly possess great potential to match the gradually stricter environmental standard. PMID:22482495

  19. CMS High Level Trigger Timing Measurements

    NASA Astrophysics Data System (ADS)

    Richardson, Clint

    2015-12-01

    The two-level trigger system employed by CMS consists of the Level 1 (L1) Trigger, which is implemented using custom-built electronics, and the High Level Trigger (HLT), a farm of commercial CPUs running a streamlined version of the offline CMS reconstruction software. The operational L1 output rate of 100 kHz, together with the number of CPUs in the HLT farm, imposes a fundamental constraint on the amount of time available for the HLT to process events. Exceeding this limit impacts the experiment's ability to collect data efficiently. Hence, there is a critical need to characterize the performance of the HLT farm as well as the algorithms run prior to start up in order to ensure optimal data taking. Additional complications arise from the fact that the HLT farm consists of multiple generations of hardware and there can be subtleties in machine performance. We present our methods of measuring the timing performance of the CMS HLT, including the challenges of making such measurements. Results for the performance of various Intel Xeon architectures from 2009-2014 and different data taking scenarios are also presented.

  20. Exposure to unusually high indoor radon levels

    SciTech Connect

    Rasheed, F.N. )

    1993-03-27

    Unusually high indoor radon concentrations were reported in a small village in western Tyrol, Austria. The authors have measured the seasonal course of indoor radon concentrations in 390 houses of this village. 71% of houses in winter and 33% in summer, showed radon values on the ground floor above the Austrian action level of 400 Bq/cm[sup 3]. This proportion results in an unusually high indoor radon exposure of the population. The radon source was an 8,700-year-old rock slide of granite gneiss, the largest of the alpine crystalline rocks. It has a strong emanating power because its rocks are heavily fractured and show a slightly increased uranium content. Previous reports show increased lung cancer mortality, myeloid leukemia, kidney cancer, melanoma, and prostate cancer resulting from indoor radon exposure. However, many studies fail to provide accurate information on indoor radon concentrations, classifying them merely as low, intermediate, and high, or they record only minor increases in indoor radon concentrations. Mortality data for 1970-91 were used to calculate age and sex standardized mortality rates (SMR) for 51 sites of carcinoma. The total population of Tyrol were controls. A significantly higher risk was recorded for lung cancer. The high SMR for lung cancer in female subjects is especially striking. Because the numbers were low for the other cancer sites, these were combined in one group to calculate the SMR. No significant increase in SMR was found for this group.

  1. High Level Waste Disposal System Optimization

    SciTech Connect

    Dirk Gombert; M. Connolly; J. Roach; W. Holtzscheiter

    2005-02-01

    The high level waste (HLW) disposal system consists of the Yucca Mountain Facility (YMF) and waste product (e.g. glass) generation facilities. Responsibility for management is shared between the U. S. Department of Energy (DOE) Offices of Civilian Radioactive Waste Management (DOE-RW) and Environmental Management (DOE-EM). The DOE-RW license application and the Waste Acceptance System Requirements Document (WASRD), as well as the DOE-EM Waste Acceptance Product Specification for Vitrified High Level Waste Forms (WAPS) govern the overall performance of the system. This basis for HLW disposal should be reassessed to consider waste form and process technology research and development (R&D), which have been conducted by DOE-EM, international agencies (i.e. ANSTO, CEA), and the private sector; as well as the technical bases for including additional waste forms in the final license application. This will yield a more optimized HLW disposal system to accelerate HLW disposition, more efficient utilization of the YMF, and overall system cost reduction.

  2. Technetium Chemistry in High-Level Waste

    SciTech Connect

    Hess, Nancy J.

    2006-06-01

    Tc contamination is found within the DOE complex at those sites whose mission involved extraction of plutonium from irradiated uranium fuel or isotopic enrichment of uranium. At the Hanford Site, chemical separations and extraction processes generated large amounts of high level and transuranic wastes that are currently stored in underground tanks. The waste from these extraction processes is currently stored in underground High Level Waste (HLW) tanks. However, the chemistry of the HLW in any given tank is greatly complicated by repeated efforts to reduce volume and recover isotopes. These processes ultimately resulted in mixing of waste streams from different processes. As a result, the chemistry and the fate of Tc in HLW tanks are not well understood. This lack of understanding has been made evident in the failed efforts to leach Tc from sludge and to remove Tc from supernatants prior to immobilization. Although recent interest in Tc chemistry has shifted from pretreatment chemistry to waste residuals, both needs are served by a fundamental understanding of Tc chemistry.

  3. High accuracy electronic material level sensor

    DOEpatents

    McEwan, Thomas E.

    1997-01-01

    The High Accuracy Electronic Material Level Sensor (electronic dipstick) is a sensor based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line or guide wire that is partially immersed in the material being measured; a launcher plate is positioned at the beginning of the guide wire. Reflected pulses are produced at the material interface due to the change in dielectric constant. The time difference of the reflections at the launcher plate and at the material interface are used to determine the material level. Improved performance is obtained by the incorporation of: 1) a high accuracy time base that is referenced to a quartz crystal, 2) an ultrawideband directional sampler to allow operation without an interconnect cable between the electronics module and the guide wire, 3) constant fraction discriminators (CFDs) that allow accurate measurements regardless of material dielectric constants, and reduce or eliminate errors induced by triple-transit or "ghost" reflections on the interconnect cable. These improvements make the dipstick accurate to better than 0.1%.

  4. High accuracy electronic material level sensor

    DOEpatents

    McEwan, T.E.

    1997-03-11

    The High Accuracy Electronic Material Level Sensor (electronic dipstick) is a sensor based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line or guide wire that is partially immersed in the material being measured; a launcher plate is positioned at the beginning of the guide wire. Reflected pulses are produced at the material interface due to the change in dielectric constant. The time difference of the reflections at the launcher plate and at the material interface are used to determine the material level. Improved performance is obtained by the incorporation of: (1) a high accuracy time base that is referenced to a quartz crystal, (2) an ultrawideband directional sampler to allow operation without an interconnect cable between the electronics module and the guide wire, (3) constant fraction discriminators (CFDs) that allow accurate measurements regardless of material dielectric constants, and reduce or eliminate errors induced by triple-transit or ``ghost`` reflections on the interconnect cable. These improvements make the dipstick accurate to better than 0.1%. 4 figs.

  5. Feeling Gravity's Pull: Gravity Modeling. The Gravity Field of Mars

    NASA Technical Reports Server (NTRS)

    Lemoine, Frank; Smith, David; Rowlands, David; Zuber, Maria; Neumann, G.; Chinn, Douglas; Pavlis, D.

    2000-01-01

    Most people take the constant presence of gravitys pull for granted. However, the Earth's gravitational strength actually varies from location to location. This variation occurs because mass, which influences an object's gravitational pull, is not evenly distributed within the planet. Changes in topography, such as glacial movement, an earthquake, or a rise in the ocean level, can subtly affect the gravity field. An accurate measurement of the Earth's gravity field helps us understand the distribution of mass beneath the surface. This insight can assist us in locating petroleum, mineral deposits, ground water, and other valuable substances. Gravity mapping can also help notice or verify changes in sea surface height and other ocean characteristics. Such changes may indicate climate change from polar ice melting and other phenomena. In addition, gravity mapping can indicate how land moves under the surface after earthquakes and other plate tectonic processes. Finally, changes in the Earth's gravity field might indicate a shift in water distribution that could affect agriculture, water supplies for population centers, and long-term weather prediction. Scientists can map out the Earth's gravity field by watching satellite orbits. When a satellite shifts in vertical position, it might be passing over an area where gravity changes in strength. Gravity is only one factor that may shape a satellite's orbital path. To derive a gravity measurement from satellite movement, scientists must remove other factors that might affect a satellite's position: 1. Drag from atmospheric friction. 2. Pressure from solar radiation as it heads toward Earth and. as it is reflected off the surface of the Earth 3. Gravitational pull from the Sun, the Moon, and other planets in the Solar System. 4. The effect of tides. 5. Relativistic effects. Scientists must also correct for the satellite tracking process. For example, the tracking signal must be corrected for refraction through the atmosphere of the Earth. Supercomputers can calculate the effect of gravity for specific locations in space following a mathematical process known as spherical harmonics, which quantifies the gravity field of a planetary body. The process is based on Laplace's fundamental differential equation of gravity. The accuracy of a spherical harmonic solution is rated by its degree and order. Minute variations in gravity are measured against the geoid, a surface of constant gravity acceleration at mean sea level. The geoid reference gravity model strength includes the central body gravitational attraction (9.8 m/sq s) and a geopotential variation in latitude partially caused by the rotation of the Earth. The rotational effect modifies the shape of the geoid to be more like an ellipsoid, rather than a perfect, circle. Variations of gravity strength from the ellipsoidal reference model are measured in units called milli-Galileos (mGals). One mGal equals 10(exp -5) m/sq s. Research projects have also measured the gravity fields of other planetary bodies, as noted in the user profile that follows. From this information, we may make inferences about our own planet's internal structure and evolution. Moreover, mapping the gravity fields of other planets can help scientists plot the most fuel-efficient course for spacecraft expeditions to those planets.

  6. A novel strategy to construct yeast Saccharomyces cerevisiae strains for very high gravity fermentation.

    PubMed

    Tao, Xianglin; Zheng, Daoqiong; Liu, Tianzhe; Wang, Pinmei; Zhao, Wenpeng; Zhu, Muyuan; Jiang, Xinhang; Zhao, Yuhua; Wu, Xuechang

    2012-01-01

    Very high gravity (VHG) fermentation is aimed to considerably increase both the fermentation rate and the ethanol concentration, thereby reducing capital costs and the risk of bacterial contamination. This process results in critical issues, such as adverse stress factors (ie., osmotic pressure and ethanol inhibition) and high concentrations of metabolic byproducts which are difficult to overcome by a single breeding method. In the present paper, a novel strategy that combines metabolic engineering and genome shuffling to circumvent these limitations and improve the bioethanol production performance of Saccharomyces cerevisiae strains under VHG conditions was developed. First, in strain Z5, which performed better than other widely used industrial strains, the gene GPD2 encoding glycerol 3-phosphate dehydrogenase was deleted, resulting in a mutant (Z5?GPD2) with a lower glycerol yield and poor ethanol productivity. Second, strain Z5?GPD2 was subjected to three rounds of genome shuffling to improve its VHG fermentation performance, and the best performing strain SZ3-1 was obtained. Results showed that strain SZ3-1 not only produced less glycerol, but also increased the ethanol yield by up to 8% compared with the parent strain Z5. Further analysis suggested that the improved ethanol yield in strain SZ3-1 was mainly contributed by the enhanced ethanol tolerance of the strain. The differences in ethanol tolerance between strains Z5 and SZ3-1 were closely associated with the cell membrane fatty acid compositions and intracellular trehalose concentrations. Finally, genome rearrangements in the optimized strain were confirmed by karyotype analysis. Hence, a combination of genome shuffling and metabolic engineering is an efficient approach for the rapid improvement of yeast strains for desirable industrial phenotypes. PMID:22363590

  7. Detection method and observed data of high-energy gamma rays under the influence of quantum gravity

    SciTech Connect

    Kifune, T.

    2014-05-20

    The interaction of high-energy particles affected by quantum gravity is argued from the experimental viewpoint of raising a question, 'our detection method for high-energy γ-rays supplies trustworthy observation data and we are now seeing the true image of the universe through high-energy γ-rays?' The modified dispersion relation (MDR) for particles' energy and momentum is applied to the equation of energy-momentum conservation in particle reactions, to study the restriction imposed on the kinematic state of high-energy particles by the Lorentz invariance violation (LIV) due to quantum gravity, as a function of the incident particle energy of the reaction. The result suggests that the interaction utilized for γ-ray detection is not free from the effect of quantum gravity when γ-ray energy is higher than 10{sup 13} ∼ 10{sup 17} eV depending on models of MDR. Discussion is presented on the prospect of finding clear evidence of the LIV effect from γ-ray observations, as well as on the radiation and propagation mechanism of γ-rays under the influence of the LIV effect.

  8. Fast fabrication of W-Cu functionally graded material by high-gravity combustion synthesis and melt-infiltration

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Guo, S. B.; Liu, G. H.; Chen, Y. X.; Li, J. T.

    2014-02-01

    W-Cu functionally graded material (FGM, 75 wt% W + 25 wt% Cu-40 wt% W + 60 wt% Cu) has been prepared by a method of high-gravity combustion synthesis and melt-infiltration in a short time (?5 min). The infiltration mechanism in the high-gravity field was investigated. The W-Cu FGM showed an overall relative density of ?97% and gradually-varying properties in terms of density, micro hardness, coefficient of thermal expansion. Especially, the W-Cu FGM exhibited a coefficient of thermal expansion between those of W and Cu, and thus could be used as a transition layer between W and Cu to relax the thermal stresses.

  9. The effects of gravity level during directional solidification on the microstructure of hypermonotectic Al-In-Sn alloys

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Kaukler, W. F.

    1986-01-01

    Five hypermonotectic Al-In-Sn compositions were directionally solidified in a Bridgman-type furnace at normal gravity and during aircraft low-gravity maneuvers. The tendency of the Al-30In alloy to form an indium-rich band at the start of unidirectional growth (SUG) made it difficult to study the integration of L sub 2 into the solidification interface. Hypermonotectic compositions closer to monotectic slightly hypermonotectic caused only a partial band on L sub 2 to form at SUG and allowed the study of such variables as gravity, composition, and monotectic dome height on integration of excess L sub 2 into the solid plus L sub 2 interface. It was found that formation of aligned composite structures for the Al-In-Sn system is not only a function of G and R but also of the degree to which the composition varies from monotectic. Most of the aligned fibrous structures formed from hypermonotectic Al-In-Sn had spacings that were of the order of irregular fibrous structures reported for on monotectic Al-In-Sn. The spacings for the large fibers and aligned globules found for ground and low-gravity processed Al-In-18-Sn-22, respectively, were significantly larger than the others measured and were of the order expected for cell spacings under the growth conditions utilized. It was found that the integration into the solidification front of excess L sub 2 in low gravity was a function of the Sn composition of the alloy.

  10. Gravity effects obtained from global hydrology models in comparison with high precision gravimetric time series

    NASA Astrophysics Data System (ADS)

    Wziontek, Hartmut; Wilmes, Herbert; Güntner, Andreas; Creutzfeldt, Benjamin

    2010-05-01

    Water mass changes are a major source of variations in residual gravimetric time series obtained from the combination of observations with superconducting and absolute gravimeters. Changes in the local water storage are the main influence, but global variations contribute to the signal significantly. For three European gravity stations, Bad Homburg, Wettzell and Medicina, different global hydrology models are compared. The influence of topographic effects is discussed and due to the long-term stability of the combined gravity time series, inter-annual signals in model data and gravimetric observations are compared. Two sources of influence are discriminated, i.e., the effect of a local zone with an extent of a few kilometers around the gravimetric station and the global contribution beyond 50km. Considering their coarse resolution and uncertainties, local effects calculated from global hydrological models are compared with the in-situ gravity observations and, for the station Wettzell, with local hydrological monitoring data.

  11. Umbra's High Level Architecture (HLA) Interface

    SciTech Connect

    GOTTLIEB, ERIC JOSEPH; MCDONALD, MICHAEL J.; OPPEL III, FRED J.

    2002-04-01

    This report describes Umbra's High Level Architecture HLA library. This library serves as an interface to the Defense Simulation and Modeling Office's (DMSO) Run Time Infrastructure Next Generation Version 1.3 (RTI NG1.3) software library and enables Umbra-based models to be federated into HLA environments. The Umbra library was built to enable the modeling of robots for military and security system concept evaluation. A first application provides component technologies that ideally fit the US Army JPSD's Joint Virtual Battlespace (JVB) simulation framework for Objective Force concept analysis. In addition to describing the Umbra HLA library, the report describes general issues of integrating Umbra with RTI code and outlines ways of building models to support particular HLA simulation frameworks like the JVB.

  12. High-level connectionist models. Semiannual report

    SciTech Connect

    Pollack, J.B.

    1989-08-01

    The major achievement of this semiannum was the significant revision and extension of the Recursive Auto-Associative Memory (RAAM) work for publication in the journal Artificial Intelligence. Included as an appendix to this report, the article includes several new elements: (1) Background - The work was more clearly set into the area of recursive distributed representations, machine learning, and the adequacy of the connectionist approach for high-level cognitive modeling; (2) New Experiment - RAAM was applied to finding compact representations for sequences of letters; (3) Analysis - The developed representations were analyzed as features which range from categorical to distinctive. Categorical features distinguish between conceptual categories while distinctive features vary within categories and discriminate or label the members. The representations were also analyzed geometrically; and (4) Applications - Feasibility studies were performed and described on inference by association, and on using RAAM-generated patterns along with cascaded networks for natural language parsing. Both of these remain long-term goals of the project.

  13. Gravity fed Hg heat pipe - Its use in the production of a high purity, fixed density of Hg atoms

    NASA Astrophysics Data System (ADS)

    Schlie, L. A.; Jusinski, L. E.; Rathge, R. D.

    1980-04-01

    A modified heat pipe employing Hg as the working fluid and utilizing gravity to return the liquid Hg from the condensative to the evaporative zone is described. This device provides an easy and rapid means of producing a fixed density of Hg atoms of high purity for any test cell configuration without employing elaborate Hg distillation techniques. Densities from 10 to the 16th to 10 to the 20th/cu cm can be easily acquired with a variable inert gas density.

  14. Global observations of gravity waves from High Resolution Dynamics Limb Sounder temperature measurements: A yearlong record of temperature amplitude and vertical wavelength

    NASA Astrophysics Data System (ADS)

    Yan, Xiuping; Arnold, Neil; Remedios, John

    2010-05-01

    Global observations of gravity waves have been performed using the High Resolution Dynamics Limb Sounder (HIRDLS) temperature data. A background field that was derived by dynamically calculating 31 day (15 day) means to block the stationary component and the slowly varying planetary-scale waves, was first subtracted from the HIRDLS temperature measurements. An additional step was then taken to remove rapidly moving planetary-scale waves by developing an along-track temperature filter, which was created by averaging the profiles within a 1000 km along-track window. Finally, each individual temperature perturbation vertical profile was analyzed using a fast Fourier transform to estimate gravity wave temperature amplitudes and vertical wavelengths. The investigation of the monthly mean gravity wave temperature amplitudes for the year 2006 found that gravity wave activity in the stratosphere is highly variable with season and can be very orographically dependent, especially in the winter extratropics. The monthly zonal means show that the peak vertical wavelengths correspond closely to the peak amplitudes. The increasing amplitudes and vertical wavelengths are faster and generated at lower altitudes in the winter extratropical and high-latitude stratosphere than those in the summer tropical stratosphere. This is consistent with the lower source altitudes of orographic gravity waves in the extratropics and high latitudes and the higher source altitudes of convectively generated gravity waves in the tropics. Three cases were studied for the observed gravity waves over large mountain ranges using the European Centre for Medium-Range Weather Forecasts wind data. Investigations of episodes of enhanced gravity wave activity over the southern Andes, the Cascade Range, and the Rockies in winter months of 2006 indicate that orographic gravity waves refract downwind from the mountains and propagate along the direction of the intense winds. By way of contrast, observations of gravity waves around the Himalayas show a strong relationship with the cyclones in that region.

  15. Time-dependent convective flows with high viscosity contrasts under micro gravity conditions.

    NASA Astrophysics Data System (ADS)

    Zaussinger, Florian; Egbers, Christoph; Krebs, Andreas; Schwarzbach, Felix; Kunze, Christian

    2015-04-01

    Thermal driven convection in spherical geometry is of main interest in geo- and astrophysical research. To capture certain aspects of temperature dependent viscosity we investigate the micro-gravity experiment GeoFlow-IIb, located on the ISS. This unique experimental setup consists of a bottom heated and top cooled spherical gap, filled with the silicon oil 1-Nonanol. However, rotation and varying temperature gradients can be applied, to spread the experimental parameter space. The main focus of the current mission is the investigation of time dependent convective flow structures. Since the ISS requirements makes it impossible to use tracer particles, the flow structures are captured by interferometry, whose outcome is analysed by an ground based adapted image processing technique. To guarantee valid results the experimental time of each parameter is in the order of the thermal time scale, which is about 40 min. We are presenting latest results of plume-like and sheet-like time-dependent convective patterns in the spherical shell, their evolution and temporal behaviour under high viscosity contrasts. Due to an unexpected nonlinear coupling between the temperature dependent viscosity of the working fluid and the applied dielectrophoretic force field, we are able to maintain a viscosity contrast of 50 and more. This gives the chance to compare cautiously our experimental results with theoretical assumptions of the mantle convection theory. Besides, numerical simulations in the same parameter regime are performed, which give the opportunity to deduce the internal structure of the experimental flow flied. The main focus of the presented results are the long time temporal evolution of convective plumes in the spherical gap, image capturing- and processing techniques and the deduction of the internal flow field based on planar interferometry pictures.

  16. Sensorimotor aspects of high-speed artificial gravity: III. Sensorimotor adaptation

    NASA Technical Reports Server (NTRS)

    DiZio, Paul; Lackner, James R.; Young, L. R. (Principal Investigator)

    2002-01-01

    As a countermeasure to the debilitating physiological effects of weightlessness, astronauts could live continuously in an artificial gravity environment created by slow rotation of an entire spacecraft or be exposed to brief daily "doses" in a short radius centrifuge housed within a non-rotating spacecraft. A potential drawback to both approaches is that head movements made during rotation may be disorienting and nauseogenic. These side effects are more severe at higher rotation rates, especially upon first exposure. Head movements during rotation generate aberrant vestibular stimulation and Coriolis force perturbations of the head-neck motor system. This article reviews our progress toward distinguishing vestibular and motor factors in side effects of rotation, and presents new data concerning the rates of rotation up to which adaptation is possible. We have studied subjects pointing to targets during constant velocity rotation, because these movements generate Coriolis motor perturbations of the arm but do not involve unusual vestibular stimulation. Initially, reaching paths and endpoints are deviated in the direction of the transient lateral Coriolis forces generated. With practice, subjects soon move in straighter paths and land on target once more. If sight of the arm is permitted, adaptation is more rapid than in darkness. Initial arm movement trajectory and endpoint deviations are proportional to Coriolis force magnitude over a range of rotation speeds from 5 to 20 rpm, and there is rapid, complete motor adaptation at all speeds. These new results indicate that motor adaptation to high rotation rates is possible. Coriolis force perturbations of head movements also occur in a rotating environment but adaptation gradually develops over the course of many head movements.

  17. Sensorimotor aspects of high-speed artificial gravity: III. Sensorimotor adaptation.

    PubMed

    DiZio, Paul; Lackner, James R

    As a countermeasure to the debilitating physiological effects of weightlessness, astronauts could live continuously in an artificial gravity environment created by slow rotation of an entire spacecraft or be exposed to brief daily "doses" in a short radius centrifuge housed within a non-rotating spacecraft. A potential drawback to both approaches is that head movements made during rotation may be disorienting and nauseogenic. These side effects are more severe at higher rotation rates, especially upon first exposure. Head movements during rotation generate aberrant vestibular stimulation and Coriolis force perturbations of the head-neck motor system. This article reviews our progress toward distinguishing vestibular and motor factors in side effects of rotation, and presents new data concerning the rates of rotation up to which adaptation is possible. We have studied subjects pointing to targets during constant velocity rotation, because these movements generate Coriolis motor perturbations of the arm but do not involve unusual vestibular stimulation. Initially, reaching paths and endpoints are deviated in the direction of the transient lateral Coriolis forces generated. With practice, subjects soon move in straighter paths and land on target once more. If sight of the arm is permitted, adaptation is more rapid than in darkness. Initial arm movement trajectory and endpoint deviations are proportional to Coriolis force magnitude over a range of rotation speeds from 5 to 20 rpm, and there is rapid, complete motor adaptation at all speeds. These new results indicate that motor adaptation to high rotation rates is possible. Coriolis force perturbations of head movements also occur in a rotating environment but adaptation gradually develops over the course of many head movements. PMID:14501105

  18. Reflection surveys conducted on the western side of the mid-continental gravity high

    SciTech Connect

    Taylor, R.W.; Fromm, A.J. ); Okita, P. )

    1992-01-01

    The few spatially isolated deeper drill holes available on the western side of the mid-continental gravity high have established elevation changes in the Sioux quartzite that exceed 500m within a few hundred kilometers. Thirteen, 12-fold, CMP, reflection surveys were conducted within this area to supplement the limited drilling data. These surveys used an elastic wave generator as the energy source and a digital 24 channel IFP system for recording. The survey locations were selected to best supplement the existing drill hole data. Phone spacings and near offsets were selected on the basis of walk-out surveys conducted at each reflection site. No velocity control was available and the stacking velocities were selected based on graded velocity stacks. Interval velocities, constrained by general stratigraphic considerations, were calculated from the stacking velocities. For the near surface, interval velocities were extracted from the first arrivals. The lack of velocity control did not appear to seriously degrade the interpretation of gross structural features. Both the Sioux quartzite and a deeper interface, assumed to be the top of igneous basement, were reliably mapped. The two-way times of the basement reflector varied from 400m sec to 200m sec, approximately 500m to 300m respectively. The two-way times to the top of the quartzite varied from 300 m secs to 135m secs, approximately 350m to 160m respectively. The results suggest a major northeast, southwest trending basement fault with displacements exceeding 100m. The structure of both the basement and the quartzite appear to be a faulted anticline or dome. The reflection surveys provided a cost effective method for reconnaissance studies required to establish gross structural features.

  19. Cyclone separates close gravities

    SciTech Connect

    Liller, D.I.

    1982-01-01

    The Liller patented high capacity centrifugal cyclone separator separates coals with small differences in specific gravities. The equipment operates at high throughput capacities in order to segregate high and low-grade coals in a minimum number of beneficiating steps.

  20. High-resolution residual geoid and gravity anomaly data of the northern Indian Ocean - An input to geological understanding

    NASA Astrophysics Data System (ADS)

    Sreejith, K. M.; Rajesh, S.; Majumdar, T. J.; Srinivasa Rao, G.; Radhakrishna, M.; Krishna, K. S.; Rajawat, A. S.

    2013-01-01

    Geoid data are more sensitive to density distributions deep within the Earth, thus the data are useful for studying the internal processes of the Earth leading to formation of geological structures. In this paper, we present much improved version of high resolution (1' 1') geoid anomaly map of the northern Indian Ocean generated from the altimeter data obtained from Geodetic Missions of GEOSAT and ERS-1 along with ERS-2, TOPEX/POSIDEON and JASON satellites. The geoid map of the Indian Ocean is dominated by a significant low of -106 m south of Sri Lanka, named as the Indian Ocean Geoid Low (IOGL), whose origin is not clearly known yet. The residual geoid data are retrieved from the geoid data by removing the long-wavelength core-mantle density effects using recent spherical harmonic coefficients of Earth Gravity Model 2008 (EGM2008) up to degree and order 50 from the observed geoid data. The coefficients are smoothly rolled off between degrees 30-70 in order to avoid artifacts related to the sharp truncation at degree 50. With this process we observed significant improvement in the residual geoid data when compared to the previous low-spatial resolution maps. The previous version was superposed by systematic broad regional highs and lows (like checker board) with amplitude up to 12 m, though the trends of geoid in general match in both versions. These methodical artifacts in the previous version may have arisen due to the use of old Rapp's geo-potential model coefficients, as well as sharp truncation of reference model at degree and order 50. Geoid anomalies are converted to free-air gravity anomalies and validated with cross-over corrected ship-borne gravity data of the Arabian Sea and Bay of Bengal. The present satellite derived gravity data matches well with the ship-borne data with Root Mean Square Error (RMSE) of 5.1-7.8 mGal, and this is found to be within the error limits when compared with other globally available satellite data. Spectral analysis of ship-borne and satellite data suggested that the satellite gravity data have a resolution down to 16-18 km. Further, the geoid, residual geoid and gravity anomalies are integrated with seismic data along two profiles in the Bay of Bengal and Arabian Sea, and inferences have been made in terms of density distributions at different depths. The new residual geoid anomaly map shows excellent correlation with regional tectonic features such as Sunda subduction zone, volcanic traces (Chagos-Laccadive, Ninetyeast and 85E ridges) and mid-ocean ridge systems (Central Indian and Carlsberg ridges).

  1. Impact of time variable Earth global gravity field models on precise orbits of altimetry satellites, global and regional mean sea level trends

    NASA Astrophysics Data System (ADS)

    Rudenko, Sergei; Dettmering, Denise; Esselborn, Saskia; Schöne, Tilo; Förste, Christoph; Lemoine, Jean-Michel; Neumayer, Karl-Hans

    2014-05-01

    Significant progress has been reached in the last decade in the investigation of the global gravity field of the Earth. Besides static, also time variable gravity field models have been recently developed. In this paper we study the influence of the recently developed time variable Earth global gravity field models on altimetry satellite orbits as well as on global and regional mean sea level trends computed using these orbits. We included in our analysis six gravity field models jointly developed by GFZ German Research Centre for Geosciences and Space Geodesy Research Group (CNES/GRGS) Toulouse: the stationary model EIGEN-GL04S, a stationary version of EIGEN-6S (EIGEN-6S_stat), a corrected version of EIGEN-6S and three enhanced versions of EIGEN-6S called EIGEN-6S2, EIGEN-6S2A and EIGEN-6S2B. Based on the analysis of precise orbits of the radar altimetry satellites ERS-1 (1991-1996), TOPEX/Poseidon (1992-2005), ERS-2 (1995-2006) and Envisat (2002-2011) computed by us totally over 20 years at the time periods shown for each satellite, the single-mission and multi-mission altimetry crossover analysis we found that the time variable models EIGEN-6S_corrected, EIGEN-6S2 and its two precursors EIGEN-6S2A/B perform notably better than the stationary models for the GRACE period from 2003 onwards. Thus, the use of the EIGEN-6S2 and EIGEN-6S2A/B models reduces the root-mean-square fits of satellite laser ranging observations for Envisat by 3.6%, as compared to the use of the EIGEN-GL04S model. However, for the pre-GRACE period (1991 - 2003) the stationary gravity field models EIGEN-GL04S and EIGEN-6S_stat and the EIGEN-6S2 model containing no drift terms for the degree 3-50 terms at this time interval perform superior to the ones containing drift terms for this period (EIGEN-6S_correct and EIGEN-6S2A/B). We also found, that the time variable gravity field models have low (0.1-0.2 mm/yr) impact on the global mean sea level trend. However, strong East/West differences up to 3 mm/yr were found in the regional mean sea level trends, while using orbits of all four satellites based on time variable and stationary gravity field models. We show a relation of these differences to the relative drifts of the centers-of-origin between the orbit solutions based on the time variable and stationary gravity field models. From the results of our detailed study, we conclude that the final version of the time variable gravity field model EIGEN-6S2 performs best for the four satellites tested. This model provides the most reliable and consistent sea level estimates for the whole time period from 1992 to 2011. This model is of the maximum spherical harmonic degree and order 260 and contains time series for drifts as well as annual and semiannual variations of the spherical harmonic coefficients up to degree 50.

  2. Effect of Melt Convection at Various Gravity Levels and Orientations on the Forces Acting on a Large Spherical Particle in the Vicinity of a Solidification Interface

    NASA Technical Reports Server (NTRS)

    Bune, Andris V.; Sen, Subhayu; Mukherjee, Sundeep; Catalina, Adrian; Stefanescu, Doru M.

    2000-01-01

    Numerical modeling was Undertaken to analyze the influence of both radial and axial thermal gradients on convection patterns and velocities claiming solidification of pure Al and an Al-4 wt% Cu alloy. The objective of the numerical task was to predict the influence of convective velocity on an insoluble particle near a solid/liquid (s/l) interface. These predictions were then be used to define the minimum gravity level (q) required to investigate the fundamental physics of interactions between a particle and a s/l interface. This is an ongoing NASA founded flight experiment entitled "particle engulfment and pushing by solidifying interfaces (PEP)". Steady-state calculations were performed for different gravity levels and orientations with respect to the gravity vector The furnace configuration used in this analysis is the quench module insert (QMI-1) proposed for the Material Science Research Facility (MSRF) on board the International Space Station (ISS). The general model of binary alloy solidification was based on the finite element code FIDAP. At a low g level of 10(exp -4) g(sub o) (g(sub o) = 9.8 m/square s) maximum melt convection was obtained for an orientation of 90 deg. Calculations showed that even for this worst case orientation the dominant forces acting on the particle are the fundamental drag and interfacial forces.

  3. Evaluation of the fermentation of high gravity thick sugar beet juice worts for efficient bioethanol production

    PubMed Central

    2013-01-01

    Background Sugar beet and intermediates of sugar beet processing are considered to be very attractive feedstock for ethanol production due to their content of fermentable sugars. In particular, the processing of the intermediates into ethanol is considerably facilitated because it does not require pretreatment or enzymatic treatment in contrast to production from starch raw materials. Moreover, the advantage of thick juice is high solid substance and saccharose content which eliminates problems with the storability of this feedstock. Results The objective of this study were to investigate bioethanol production from thick juice worts and the effects of their concentration, the type of mineral supplement, as well as the dose of yeast inoculum on fermentation dynamics and ethanol yield. The obtained results show that to ensure efficient ethanolic fermentation of high gravity thick juice worts, one needs to use a yeast strain with high ethanol tolerance and a large amount of inoculum. The highest ethanol yield (94.9??2.8% of the theoretical yield) and sugars intake of 96.5??2.9% were obtained after the fermentation of wort with an extract content of 250 g/kg supplemented with diammonium hydrogen phosphate (0.3 g/L of wort) and inoculated with 2 g of Ethanol Red dry yeast per L of wort. An increase in extract content in the fermentation medium from 250 g/L to 280 g/kg resulted in decreased efficiency of the process. Also the distillates originating from worts with an extract content of 250 g/kg were characterized by lower acetaldehyde concentration than those obtained from worts with an extract content of 280 g/kg. Conclusions Under the favorable conditions determined in our experiments, 38.9??1.2 L of 100% (v/v) ethyl alcohol can be produced from 100 kg of thick juice. The obtained results show that the selection of process conditions and the yeast for the fermentation of worts with a higher sugar content can improve the economic performance of the alcohol-distilling industry due to more efficient ethanol production, reduced consumption of cooling water, and energy for ethanol distillation, as well as a decreased volume of fermentation stillage. PMID:24206573

  4. Lunar gravity - Apollo 17

    NASA Technical Reports Server (NTRS)

    Sjogren, W. L.; Wimberly, R. N.; Wollenhaupt, W. R.

    1974-01-01

    Gravity results are displayed as a band of contours about 60 km wide spanning 140 deg of frontside longitude. The contours traverse Grimaldi, Mare Procellarum, Copernicus, Apennines, Mare Serenitatis, Littrow, and Mare Crisium. Redundant gravity areas previously mapped by Apollos 14, 15, 16, and the Apollo subsatellites are tabulated and show excellent consistency. Modeling of Grimaldi reveals a loading greater than the known mascons and thus makes Grimaldi the smallest known mascon feature. Copernicus' gravity profile is best modeled with a mass defect for the basin and a mass excess for the rim. Mare Serenitatis has an irregular mass distribution with central gravity highs shifted approximately 3 deg in latitude.

  5. HIGH LEVEL RF FOR THE SNS RING.

    SciTech Connect

    ZALTSMAN,A.; BLASKIEWICZ,M.; BRENNAN,J.; BRODOWSKI,J.; METH,M.; SPITZ,R.; SEVERINO,F.

    2002-06-03

    A high level RF system (HLRF) consisting of power amplifiers (PA's) and ferrite loaded cavities is being designed and built by Brookhaven National Laboratory (BNL) for the Spallation Neutron Source (SNS) project. It is a fixed frequency, two harmonic system whose main function is to maintain a gap for the kicker rise time. Three cavities running at the fundamental harmonic (h=l) will provide 40 kV and one cavity at the second harmonic (h=2) will provide 20 kV. Each cavity has two gaps with a design voltage of 10 kV per gap and will be driven by a power amplifier (PA) directly adjacent to it. The PA uses a 600kW tetrode to provide the necessary drive current. The anode of the tetrode is magnetically coupled to the downstream cell of the cavity. Drive to the PA will be provided by a wide band, solid state amplifier located remotely. A dynamic tuning scheme will be implemented to help compensate for the effect of beam loading.

  6. Decontamination of high-level waste canisters

    SciTech Connect

    Nesbitt, J.F.; Slate, S.C.; Fetrow, L.K.

    1980-12-01

    This report presents evaluations of several methods for the in-process decontamination of metallic canisters containing any one of a number of solidified high-level waste (HLW) forms. The use of steam-water, steam, abrasive blasting, electropolishing, liquid honing, vibratory finishing and soaking have been tested or evaluated as potential techniques to decontaminate the outer surfaces of HLW canisters. Either these techniques have been tested or available literature has been examined to assess their applicability to the decontamination of HLW canisters. Electropolishing has been found to be the most thorough method to remove radionuclides and other foreign material that may be deposited on or in the outer surface of a canister during any of the HLW processes. Steam or steam-water spraying techniques may be adequate for some applications but fail to remove all contaminated forms that could be present in some of the HLW processes. Liquid honing and abrasive blasting remove contamination and foreign material very quickly and effectively from small areas and components although these blasting techniques tend to disperse the material removed from the cleaned surfaces. Vibratory finishing is very capable of removing the bulk of contamination and foreign matter from a variety of materials. However, special vibratory finishing equipment would have to be designed and adapted for a remote process. Soaking techniques take long periods of time and may not remove all of the smearable contamination. If soaking involves pickling baths that use corrosive agents, these agents may cause erosion of grain boundaries that results in rough surfaces.

  7. Effects of gravity level during directional solidification on the microstructure of hypermonotectic Al-In-Sn alloys

    SciTech Connect

    Curreri, P.A.; Kaukler, W.F.

    1986-11-01

    Five hypermonotectic Al-In-Sn compositions were directionally solidified in a Bridgman-type furnace at normal gravity and during aircraft low-gravity maneuvers. The tendency of the Al-30In alloy to form an indium-rich band at the start of unidirectional growth (SUG) made it difficult to study the integration of L/sub 2/into the solidification interface. Hypermonotectic compositions closer to monotectic slightly hypermonotectic caused only a partial band on L/sub 2/to form at SUG and allowed the study of such variables as gravity, composition, and monotectic dome height on integration of excess L /sub 2/into the solid plus L/sub 2/interface. It was found that formation of aligned composite structures for the Al-In-Sn system is not only a function of G and R but also of the degree to which the composition varies from monotectic. Most of the aligned fibrous structures formed from hypermonotectic Al-In-Sn had spacings that were of the order of irregular fibrous structures reported for on monotectic Al-In-Sn. The spacings for the large fibers and aligned globules found for ground and low-gravity processed Al-In-18-Sn-22, respectively, were significantly larger than the others measured and were of the order expected for cell spacings under the growth conditions utilized. It was found that the integration into the solidification front of excess L/sub 2/in low gravity was a function of the Sn composition of the alloy.

  8. Dynamics of three-level ?-type atom interacting with one mode cavity field with both classical gravity and quantum radiation: Lie algebra approach

    NASA Astrophysics Data System (ADS)

    Abd El-Wahab, N. H.; Abdel Rady, A. S.; Osman, Abdel-Nasser A.; Salah, Ahmed

    2015-10-01

    In this paper, a model is introduced to investigate the interaction between a three-level atom and one-mode of the radiation field. The atomic motion and the classical homogenous gravitational field are taken into consideration. For this purpose, we first introduce a set of new atomic operators obeying an su(3) algebraic structure to derive an effective Hamiltonian for the system under consideration. By solving the Schrdinger equation in the interaction picture, the exact solution is given when the atom and the field are initially prepared in excited state and coherent state, respectively. The influences of the gravity parameter on the collapses-revivals phenomena, the atomic momentum diffusion, the Mandel Q-parameter, the normal squeezing phenomena and the coherent properties for the considered system are examined. It is found that the gravity parameter has important effects on the properties of these phenomena.

  9. DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

    SciTech Connect

    W. Ebert

    2001-09-20

    The purpose of this Analysis/Model Report (AMR) is to document the analyses that were done to develop models for radionuclide release from high-level waste (HLW) glass dissolution that can be integrated into performance assessment (PA) calculations conducted to support site recommendation and license application for the Yucca Mountain site. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M&O 2000a). It specifically addresses the item, ''Defense High Level Waste Glass Degradation'', of the product technical work plan. The AP-3.15Q Attachment 1 screening criteria determines the importance for its intended use of the HLW glass model derived herein to be in the category ''Other Factors for the Postclosure Safety Case-Waste Form Performance'', and thus indicates that this factor does not contribute significantly to the postclosure safety strategy. Because the release of radionuclides from the glass will depend on the prior dissolution of the glass, the dissolution rate of the glass imposes an upper bound on the radionuclide release rate. The approach taken to provide a bound for the radionuclide release is to develop models that can be used to calculate the dissolution rate of waste glass when contacted by water in the disposal site. The release rate of a particular radionuclide can then be calculated by multiplying the glass dissolution rate by the mass fraction of that radionuclide in the glass and by the surface area of glass contacted by water. The scope includes consideration of the three modes by which water may contact waste glass in the disposal system: contact by humid air, dripping water, and immersion. The models for glass dissolution under these contact modes are all based on the rate expression for aqueous dissolution of borosilicate glasses. The mechanism and rate expression for aqueous dissolution are adequately understood; the analyses in this AMR were conducted to provide models and parameter values that can be used to calculate the dissolution rates for the different modes of water contact. The analyses were conducted to identify key aspects of the mechanistic model for glass dissolution to be included in the abstracted models used for PA calculations, evaluate how the models can be used to calculate bounding values of the glass dissolution rates under anticipated water contact modes in the disposal. system, and determine model parameter values for the range of potential waste glass compositions and anticipated environmental conditions. The analysis of a bounding rate also considered the effects of the buildup of glass corrosion products in the solution contacting the glass and potential effects of alteration phase formation. Note that application of the models and model parameter values is constrained to the anticipated range of HLW glass compositions and environmental conditions. The effects of processes inherent to exposure to humid air and dripping water were not modeled explicitly. Instead, the impacts of these processes on the degradation rate were taken into account by using empirically measured parameter values. These include the rates at which water sorbs onto the glass, drips onto the glass, and drips off of the glass. The dissolution rates of glasses that were exposed to humid air and dripping water measured in laboratory tests are used to estimate model parameter values for contact by humid air and dripping water in the disposal system.

  10. Numerical solution of the altimetry-gravimetry BVP for high-resolution modelling of the altimetry-derived gravity data

    NASA Astrophysics Data System (ADS)

    ?underlk, Rbert; Mack, Marek; Minarechov, Zuzana; Mikula, Karol

    2015-04-01

    We present a numerical solution of the altimetry-gravimetry boundary-value problem using the finite volume method, which discretizes the 3D computational domain between an ellipsoidal approximation of the Earth's surface and an upper boundary given at the mean altitude of the GOCE orbits. A parallel implementation of the finite volume numerical scheme and large-scale parallel computations on clusters with distributed memory allow high-resolution modelling of the altimetry-derived gravity disturbances over oceans. Here the Dirichlet boundary conditions in form of the disturbing potential are prescribed. They are obtained by nonlinear diffusion filtering of the geopotential generated on the mean sea surface from the GRACE/GOCE-based satellite-only geopotential model. On the upper boundary, the Dirichlet boundary conditions generated from the same model are prescribed as well. Numerical experiments present the detailed gravity disturbances derived over oceans from the DTU13 mean sea surface model and the GO_CONS_GCF_2_DIR_R5 geopotential model. Their comparison with the DTU13_GRAV altimetry-derived gravity data indicates an importance of a-priori information about the mean dynamic topography for achieved accuracy, especially in zones of main ocean geosprophic surface currents.

  11. Application of low-cost algal nitrogen source feeding in fuel ethanol production using high gravity sweet potato medium.

    PubMed

    Shen, Yu; Guo, Jin-Song; Chen, You-Peng; Zhang, Hai-Dong; Zheng, Xu-Xu; Zhang, Xian-Ming; Bai, Feng-Wu

    2012-08-31

    Protein-rich bloom algae biomass was employed as nitrogen source in fuel ethanol fermentation using high gravity sweet potato medium containing 210.0 g l(-1) glucose. In batch mode, the fermentation could not accomplish even in 120 h without any feeding of nitrogen source. While, the feeding of acid-hydrolyzed bloom algae powder (AHBAP) notably promoted fermentation process but untreated bloom algae powder (UBAP) was less effective than AHBAP. The fermentation times were reduced to 96, 72, and 72 h if 5.0, 10.0, and 20.0 g l(-1) AHBAP were added into medium, respectively, and the ethanol yields and productivities increased with increasing amount of feeding AHBAP. The continuous fermentations were performed in a three-stage reactor system. Final concentrations of ethanol up to 103.2 and 104.3 g l(-1) with 4.4 and 5.3 g l(-1) residual glucose were obtained using the previously mentioned medium feeding with 20.0 and 30.0 g l(-1) AHBAP, at dilution rate of 0.02 h(-1). Notably, only 78.5 g l(-1) ethanol and 41.6 g l(-1) residual glucose were obtained in the comparative test without any nitrogen source feeding. Amino acids analysis showed that approximately 67% of the protein in the algal biomass was hydrolyzed and released into the medium, serving as the available nitrogen nutrition for yeast growth and metabolism. Both batch and continuous fermentations showed similar fermentation parameters when 20.0 and 30.0 g l(-1) AHBAP were fed, indicating that the level of available nitrogen in the medium should be limited, and an algal nitrogen source feeding amount higher than 20.0 g l(-1) did not further improve the fermentation performance. PMID:22387426

  12. Goose Bay radar observations of Earth-reflected, atmospheric gravity waves in the high-latitude ionosphere

    SciTech Connect

    Samson, J.C.; Greenwald, R.A.; Ruohoniemi, J.M.; Frey, A.; Baker, K.B. )

    1990-06-01

    In the late fall and early winter, The Johns Hopkins University HF radar at Goose Bay, Labrador, observes the effects of atmospheric gravity waves on radar transmissions that are obliquely reflected from the ionosphere and subsequently backscattered from the Earth's surface. The waves exist under a wide variety of geomagnetic conditions; however, they are particularly noticeable under quiet conditions (O {le} Kp {le} 1 +). The clearest signatures of the waves are spatially localized enhancements in the backscattered power and quasi-periodic fluctuations in the backscatter powers, Doppler velocities, and reflection heights. The waves are generally observed during daylight hours and propagate equatorward from regions of high-latitude ionospheric backscatter that are located near the ionospheric convection reversal boundary. The gravity waves appear to be generated just equatorward of the dayside flow-reversal boundary in the vicinity of the auroral electrojet at altitudes of 115 to 135 km and propagate approximately perpendicular to the boundary along azimuths ranging from 156{degree} to 180{degree}. The waves propagate obliquely downward through the lower atmosphere until they are reflected by the Earth's surface back into the upper atmosphere. The frequencies associated with these gravity waves cover the range of 0.3 to 0.6 mHz, with wavelengths of 300 to 500 km, and with average phase velocities of 110 to 180 m/s. The maximum phase speeds are 270 to 300 m/s, which is slightly less than the speed of sound in the lower atmosphere. Poleward-propagating gravity waves are sometimes observed under disturbed conditions when the polar cap and convection reversal boundary have expanded equatorward.

  13. F2-region atmospheric gravity waves due to high-power HF heating and subauroral polarization streams

    NASA Astrophysics Data System (ADS)

    Mishin, E.; Sutton, E.; Milikh, G.; Galkin, I.; Roth, C.; Frster, M.

    2012-06-01

    We report the first evidence of atmospheric gravity waves (AGWs) generated in the F2 region by high-power HF heating and subauroral polarization streams. Data come from the CHAMP and GRACE spacecraft overflying the High-frequency Active Auroral Research Program (HAARP) heating facility. These observations facilitate a new method of studying the ionosphere-thermosphere coupling in a controlled fashion by using various HF-heating regimes. They also reveal the subauroral F2 region to be a significant source of substorm AGWs, in addition to the well-known auroral E region.

  14. On the facet-skeletal transition of snow crystals - Experiments in high and low gravity

    NASA Technical Reports Server (NTRS)

    Alena, T.; Hallett, J.; Saunders, C. P. R.

    1990-01-01

    A laboratory investigation of the influence of air velocity on the growth of columnar ice crystals from the vapor over the range -3 to -5 C shows that the linear growth velocity increases and that columns transform to sheath crystals or needles as air velocity increases from a few cm/s to 40 cm/s. Comparison with a similar transition of plates to dendrites shows that, macroscopically, in both cases the facets sprout rounded tips at a critical velocity which is lower for higher ambient supersaturation. Studies in low gravity show that chamber scale convection under normal gravity may have significant influence on growth even in the absence of an imposed air velocity. Falling snow crystals become more skeletal in shape as they grow and fall with increasing velocity. This development depends critically on temperature (+ or - 0.5 C) and demonstrates that the snow crystal shape is even more dependent on environmental growth conditions that previously thought.

  15. Gravity Current - Submarine Structure Interaction: Hazard Analysis via High-Resolution Flow Simulations

    NASA Astrophysics Data System (ADS)

    Gonzales-Juez, Esteban; Constantinescu, George; Meiburg, Eckart

    2006-11-01

    Two-dimensional large eddy simulations of a compositional lock-release gravity-current interacting with a submerged square cylinder are performed in order to investigate the governing physical mechanisms. The effect of the Reynolds and Schmidt numbers, and of the gap separating the floor and the cylinder, are investigated for both full- and partial-depth release gravity currents. The results are validated with available experimental measurements. The transient forces during the initial impact stage are seen to be several times higher than the forces encountered during the later quasi-steady stage. The density stratification, which is time dependent and can be stable or unstable, has a clear influence on the flow structures that develop. Such flow structures are described in detail and related to the time variation of flow forces and floor shear stresses. The latter are discussed in the context of potential erosional patterns near the structure.

  16. The Current Status of the Space Station Biological Research Project: a Core Facility Enabling Multi-Generational Studies under Slectable Gravity Levels

    NASA Astrophysics Data System (ADS)

    Santos, O.

    2002-01-01

    The Space Station Biological Research Project (SSBRP) has developed a new plan which greatly reduces the development costs required to complete the facility. This new plan retains core capabilities while allowing for future growth. The most important piece of equipment required for quality biological research, the 2.5 meter diameter centrifuge capable of accommodating research specimen habitats at simulated gravity levels ranging from microgravity to 2.0 g, is being developed by NASDA, the Japanese space agency, for the SSBRP. This is scheduled for flight to the ISS in 2007. The project is also developing a multi-purpose incubator, an automated cell culture unit, and two microgravity habitat holding racks, currently scheduled for launch in 2005. In addition the Canadian Space Agency is developing for the project an insect habitat, which houses Drosophila melanogaster, and provides an internal centrifuge for 1 g controls. NASDA is also developing for the project a glovebox for the contained manipulation and analysis of biological specimens, scheduled for launch in 2006. This core facility will allow for experimentation on small plants (Arabidopsis species), nematode worms (C. elegans), fruit flies (Drosophila melanogaster), and a variety of microorganisms, bacteria, yeast, and mammalian cells. We propose a plan for early utilization which focuses on surveys of changes in gene expression and protein structure due to the space flight environment. In the future, the project is looking to continue development of a rodent habitat and a plant habitat that can be accommodated on the 2.5 meter centrifuge. By utilizing the early phases of the ISS to broadly answer what changes occur at the genetic and protein level of cells and organisms exposed to the ISS low earth orbit environment, we can generate interest for future experiments when the ISS capabilities allow for direct manipulation and intervention of experiments. The ISS continues to hold promise for high quality, long term, multi-generational biological studies with large sample sizes and appropriate controls.

  17. Estimating gravity wave parameters from oblique high-frequency backscatter: Modeling and analysis

    NASA Technical Reports Server (NTRS)

    Bristow, W. A.; Greenwald, R. A.

    1995-01-01

    A new technique for estimating electron density perturbation amplitudes of traveling ionospheric disturbances (TIDs), using HF radar data, is presented. TIDs are observed in HF radar data as enhancements of the ground-scattered power which propagate through the radar's field of view. These TIDs are the ionospheric manifestation of atmospheric acoustic-gravity waves. TID electron density perturbation amplitudes were estimated by simulating the radar returns, using HF ray tracing through a model ionosphere perturbed by a model gravity wave. The simulation determined the return power in the ground-scattered portion of the signal as a function of range, and this was compared to HF radar data from the Goose Bay HF radar at a time when evidence of gravity waves was present in the data. By varying the amplitude of the electron density perturbation in the model it was possible to estimate the perturbation of the actual wave. It was found that the perturbations that are observed by the Goose Bay HF radar are of the order of 20% to 35%. It was also found that the number of observable power enhancements, and the relative amplitudes of these enhancements, depended on the vertical thickness of the gravity wave's source region. From the simulations and observations it was estimated that the source region for the case presented here was approximately 20 km thick. In addition, the energy in the wave packet was calculated and compared to an estimate of the available energy in the source region. It was found that the wave energy was about 0.2% of the estimated available source region energy.

  18. Gravity Waves

    Atmospheric Science Data Center

    2013-04-19

    article title:  Gravity Waves Ripple over Marine Stratocumulus Clouds ... Imaging SpectroRadiometer (MISR), a fingerprint-like gravity wave feature occurs over a deck of marine stratocumulus clouds. Similar ... that occur when a pebble is thrown into a still pond, such "gravity waves" sometimes appear when the relatively stable and stratified air ...

  19. Integration of P- and SH-wave high-resolution seismic reflection and micro-gravity techniques to improve interpretation of shallow subsurface structure: New Madrid seismic zone

    USGS Publications Warehouse

    Bexfield, C.E.; McBride, J.H.; Pugin, Andre J.M.; Ravat, D.; Biswas, S.; Nelson, W.J.; Larson, T.H.; Sargent, S.L.; Fillerup, M.A.; Tingey, B.E.; Wald, L.; Northcott, M.L.; South, J.V.; Okure, M.S.; Chandler, M.R.

    2006-01-01

    Shallow high-resolution seismic reflection surveys have traditionally been restricted to either compressional (P) or horizontally polarized shear (SH) waves in order to produce 2-D images of subsurface structure. The northernmost Mississippi embayment and coincident New Madrid seismic zone (NMSZ) provide an ideal laboratory to study the experimental use of integrating P- and SH-wave seismic profiles, integrated, where practicable, with micro-gravity data. In this area, the relation between "deeper" deformation of Paleozoic bedrock associated with the formation of the Reelfoot rift and NMSZ seismicity and "shallower" deformation of overlying sediments has remained elusive, but could be revealed using integrated P- and SH-wave reflection. Surface expressions of deformation are almost non-existent in this region, which makes seismic reflection surveying the only means of detecting structures that are possibly pertinent to seismic hazard assessment. Since P- and SH-waves respond differently to the rock and fluid properties and travel at dissimilar speeds, the resulting seismic profiles provide complementary views of the subsurface based on different levels of resolution and imaging capability. P-wave profiles acquired in southwestern Illinois and western Kentucky (USA) detect faulting of deep, Paleozoic bedrock and Cretaceous reflectors while coincident SH-wave surveys show that this deformation propagates higher into overlying Tertiary and Quaternary strata. Forward modeling of micro-gravity data acquired along one of the seismic profiles further supports an interpretation of faulting of bedrock and Cretaceous strata. The integration of the two seismic and the micro-gravity methods therefore increases the scope for investigating the relation between the older and younger deformation in an area of critical seismic hazard. ?? 2006 Elsevier B.V. All rights reserved.

  20. Generation of Acoustic Gravity Waves by Periodic Radio Transmissions from a High-Power Ionospheric Heater

    NASA Astrophysics Data System (ADS)

    Frolov, Vladimir; Chernogor, Leonid; Rozumenko, Victor

    The Radiophysical Research Institute (Nizhny Novgorod, Russia) and Kharkiv V. N. Karazin National University (Kharkiv, Ukraine) have studied opportunities for the effective generation of acoustic gravity waves (AGWs) in 3 - 180-min period range. The excitation of such waves was conducted for the last several years using the SURA heating facility (Nizhny Novgorod). The detection of the HF-induced AGWs was carried out in the Radiophysical Observatory located near Kharkiv City at a distance of about 960 km from the SURA. A coherent radar for vertical sounding, an ionosonde, and magnetometer chains were used in our measurements. The main results are the following (see [1-5]): 1. Infrasound oscillation trains with a period of 6 min are detected during periodic SURA heater turn-on and -off. Similar oscillation trains are detected after long time pumping, during periodic transmissions with a period of 20 s, as well as after pumping turn-off. The train recordings begin 28 - 54 min after the heater turn-on or -off, and the train propagation speeds are about 300 - 570 m/s, the value of which is close to the sound speed at upper atmospheric altitudes. The amplitude of the Doppler shift frequency is of 10 - 40 mHz, which fits to the 0.1 - 0.3% electron density disturbances at ionospheric altitudes. The amplitude of the infrasound oscillations depends on the SURA mode of operation and the state of the upper atmosphere and ionosphere. 2. High-power radio transmissions stimulate the generation (or enhancement) of waves at ionospheric altitudes in the range of internal gravity wave periods. The HF-induced waves propagate with speeds of 360 - 460 m/s and produce changes in electron density with amplitudes of 2 - 3%. The generation of such periodic perturbations is more preferable with periods of 10 - 60 minutes. Their features depend significantly on the heater mode of operation. It should be stressed that perturbation intensity increases when a pumping wave frequency approaches the F _{_2} layer critical frequency. High-power periodic radio transmissions are capable of enhancing/damping natural wave perturbations generated by the solar terminator. 3. The study has demonstrated that the generation and propagation of AGWs with periods close to the natural oscillation periods of the atmosphere is possible. The duration of AGW oscillation trains does not dependent on the duration of turn-on/-off trains, but it is determined by changes in the current state of the atmosphere-ionosphere-magnetosphere system in general. The period of the AGW oscillation trains is determined by the period or semi-period of the pumping. It means that the mechanism of AGW generation in this case is distinct from the agreed-upon mechanism developed earlier. The AGWs, whose periods are 5 - 10% greater than the Brunt-Vaisala period, exhibit group velocities less than the speed of sound that is of about 80 - 160 m/s. They induce electron density perturbations of about 1.1 - 1.5%. The AGW generation has the following features. When the effective radiated power (ERP) is 50 MW or less, AGWs are not detected; they are reliably observed when the ERP is equal or larger than about 100 MW. Geomagnetic storms play a dual role in the AGW generation because they: (i) increase amplitudes of AGWs with 4 - 6-min and 8 - 12-min periods and (ii) yet enhance background oscillations. The latter hampers the identification of the HF-induced oscillations. Moderate magnetic storms do not markedly exert an influence on the amplitudes of oscillations with 13 - 17-min periods. 4. The quasi-periodic variations in the horizontal components of the geomagnetic field with 8 - 12-min periods become observable near Kharkiv 35 - 45 min after the beginning of pumping. Their speeds are 355 - 460 m/s, and they form trains 40 - 90 min in duration when the [5-min on, 5-min off] or [10-min on, 10-min off] heater timing is used. The 12 - 18-min period variations become observable 35 - 45 min after the beginning of pumping. Their speeds are 355 - 460 m/s, and they form trains 55 - 90 min in duration when the [15-min on, 15-min off] heater timing is used. The revealed HF-induced geomagnetic pulsations are associated with the modulation of the ionospheric dynamo current system over Kharkiv by the AGWs produced by the periodic HF pumping of the ionosphere. References: 1. Chernogor L.F. and Frolov V.L. // Radiophys. Quant. Electron., Engl. Transl., 2012. Vol. 55(1-2), p.14. 2. Chernogor L.F., Frolov, and Pushin V.F. // Radiophys. Quant. Electron., Engl. Transl., 2012. Vol. 55(5), p.327. 3. Chernogor L.F. and Frolov V.L. // Radiophys. Quant. Electron., Engl. Transl., 2013. Vol. 56(4), p.219. 4. Chernogor L.F. and Frolov V.L. // Radiophys. Quant. Electron., Engl. Transl., 2013. Vol. 56(5), p.307. 5. Chernogor L.F. and Frolov V.L. // Radiophys. Quant. Electron., Engl. Transl., 2014. Vol. 57 (submitted for publication).

  1. High Ozone Levels Dangerous for Critically Ill

    MedlinePLUS

    ... this is the first study to associate ozone pollution with the disease. However, the study did not ... suggesting the need to reduce levels of ozone pollution, according to a news release from the journal. ...

  2. The effects of winds and atmospheric structure on long-range gravity wave propagation at high latitudes

    NASA Astrophysics Data System (ADS)

    Heale, C. J.; Snively, J. B.; Hickey, M. P.

    2013-12-01

    Recent studies of waves over Halley, Antarctica by Nielsen et al. [JASTP, 71,8 2009; JGR, 117, D5, 2012] suggest that gravity waves at high latitude sites are less likely to exhibit narrow ducting in the mesosphere and lower thermosphere (MLT) region than at mid-to-low latitude sites, and thus may be less likely to travel large horizontal distances. These studies estimate that 82% of the wave events are freely propagating (not ducted), when compared to ~25% in some mid/low-latitude studies [Isler et al., JGR, 102, D22, 1997]. This is due to relatively weak meridional winds at high latitudes, which are typically not strong enough to provide a Doppler ducted environment. However, thermal reflection of gravity waves may still occur in the lower thermosphere, which may lead to deep non-ideal thermal ducting between the thermosphere and ground, providing another mechanism for long range propagation that would not necessarily be identifiable in measurements at OH airglow heights. In general, the horizontal propagation of gravity waves is highly dependent on the wave parameters and background atmosphere/wind structure. This complex interaction will determine dissipation processes, propagation trajectories, packet spatial extents and spectral evolutions, among other things. We use a 2D, nonlinear, compressible model [e.g., Snively et al., JGR, 113, A06303, 2008] to study specific cases of long-range propagation of atmospheric gravity waves in high-latitude atmospheric conditions, and a 1D steady-state compressible full-wave model [e.g., Hickey et al., JGR, 102, A6 1997] to study effects of varying atmospheric parameters. We investigate possible conditions which are (or are not) conducive to sustained propagation via reflections, and how these conditions may vary in space or time. Background temperature and wind structure are specified to represent profiles over Halley, Antarctica, in order to compare with observations at the same location and to assess the effects of ambient atmospheric structure and dynamics on the long-range propagation of waves. We find in particular that the thermospheric winds can facilitate strong reflection or filtering effects depending on wave propagation direction at high latitudes, and that the dissipation height relative to the reflection height determines whether a wave is likely to sustain its amplitude over large horizontal distances.

  3. Statistics of high-level scene context

    PubMed Central

    Greene, Michelle R.

    2013-01-01

    Context is critical for recognizing environments and for searching for objects within them: contextual associations have been shown to modulate reaction time and object recognition accuracy, as well as influence the distribution of eye movements and patterns of brain activations. However, we have not yet systematically quantified the relationships between objects and their scene environments. Here I seek to fill this gap by providing descriptive statistics of object-scene relationships. A total of 48, 167 objects were hand-labeled in 3499 scenes using the LabelMe tool (Russell et al., 2008). From these data, I computed a variety of descriptive statistics at three different levels of analysis: the ensemble statistics that describe the density and spatial distribution of unnamed “things” in the scene; the bag of words level where scenes are described by the list of objects contained within them; and the structural level where the spatial distribution and relationships between the objects are measured. The utility of each level of description for scene categorization was assessed through the use of linear classifiers, and the plausibility of each level for modeling human scene categorization is discussed. Of the three levels, ensemble statistics were found to be the most informative (per feature), and also best explained human patterns of categorization errors. Although a bag of words classifier had similar performance to human observers, it had a markedly different pattern of errors. However, certain objects are more useful than others, and ceiling classification performance could be achieved using only the 64 most informative objects. As object location tends not to vary as a function of category, structural information provided little additional information. Additionally, these data provide valuable information on natural scene redundancy that can be exploited for machine vision, and can help the visual cognition community to design experiments guided by statistics rather than intuition. PMID:24194723

  4. High-Gravity Carbonation Process for Enhancing CO2 Fixation and Utilization Exemplified by the Steelmaking Industry.

    PubMed

    Pan, Shu-Yuan; Chen, Yi-Hung; Chen, Chun-Da; Shen, Ai-Lin; Lin, Michael; Chiang, Pen-Chi

    2015-10-20

    The high-gravity carbonation process for CO2 mineralization and product utilization as a green cement was evaluated using field operation data from the steelmaking industry. The effect of key operating factors, including rotation speed, liquid-to-solid ratio, gas flow rate, and slurry flow rate, on CO2 removal efficiency was studied. The results indicated that a maximal CO2 removal of 97.3% was achieved using basic oxygen furnace slag at a gas-to-slurry ratio of 40, with a capture capacity of 165 kg of CO2 per day. In addition, the product with different carbonation conversions (i.e., 0%, 17%, and 48%) was used as supplementary cementitious materials in blended cement at various substitution ratios (i.e., 0%, 10%, and 20%). The performance of the blended cement mortar, including physicochemical properties, morphology, mineralogy, compressive strength, and autoclave soundness, was evaluated. The results indicated that the mortar with a high carbonation conversion of slag exhibited a higher mechanical strength in the early stage than pure portland cement mortar, suggesting its suitability for use as a high early strength cement. It also possessed superior soundness compared to the mortar using fresh slag. Furthermore, the optimal operating conditions of the high-gravity carbonation were determined by response surface models for maximizing CO2 removal efficiency and minimizing energy consumption. PMID:26397167

  5. Numerical study of high frequency vibration influence on measurement of Soret and diffusion coefficients in low gravity conditions

    NASA Astrophysics Data System (ADS)

    Lyubimova, T.; Shklyaeva, E.; Legros, J.-C.; Shevtsova, V.; Roux, B.

    The paper deals with the numerical investigation of the influence of static and vibrational acceleration on the measurement of diffusion and Soret coefficients in binary mixtures, in low gravity conditions. In space experiments, liquids with inhomogeneous composition are prepared by Soret diffusion under an imposed temperature gradient. So, the process under consideration consists of two stages. First, a mixture is maintained at a fixed temperature gradient which results in a thermal diffusion separation of the components - the value of the Soret coefficient is calculated from the steady-state characteristics. The second stage corresponds to the diffusion process under isothermal external conditions and permits calculation of the diffusion coefficient. The modeling is made for a rectangular cavity subjected to static acceleration (normal gravity) and/or vibrational accelerations with different levels and orientations. In the last cases, the vibration period is assumed to be small in comparison with hydrodynamical time scales and the product of their amplitude; in addition, the Boussinesq parameter is small compared to the cavity size. This allows to decompose the processes into slowly varying (time-average) and quickly oscillating (pulsational) components and to implement appropriate equations for the vibrational convection. The influence of acceleration level on transient process and steady-state characteristics is identified for various binary mixtures that are candidates for space experiments.

  6. Numerical study of high frequency vibration influence on measurement of Soret and diffusion coefficients in low gravity conditions

    NASA Astrophysics Data System (ADS)

    Legros, J.-C.; Shevtsova, V.; Lyubimova, T.; Shklyaeva, E. V.; Roux, B.

    The paper deals with the numerical investigation of static and vibrational acceleration influence on the measurement of diffusion and Soret coefficients in binary mixtures, in low gravity conditions. In space experiments, the states with inhomogeneous composition are prepared by the diffusion due to the Soret effect under imposed temperature gradient. So, the process under consideration consists of two stages: at the first stage a mixture is maintained at a fixed temperature gradient which results in a thermal diffusion separation of the components - the value of the Soret coefficient is calculated from the steady-state characteristics, the second stage corresponds to the diffusion process under isothermal external conditions and allows to calculate the diffusion coefficient. The modeling is made for a rectangular cavity subjected to static acceleration (normal gravity) and/or vibrational accelerations with different levels and orientations. In the last cases, the vibration period is assumed to be small in comparison with hydrodynamical time scales and the product of their amplitude; in addition, the Boussinesq parameter is small compared to the cavity size. This allows to decompose the processes into slowly varying (time-average) and quickly oscillating (pulsational) components and to implement appropriate equations for the vibrational convection [1]. The influence of acceleration level on transient process and steady-state characteristics is identified for various binary mixtures being candidates for space experiments. References 1. G.Z.Gershuni, D.V.Lyubimov. Thermal Vibrational Convection. Wiley: N.Y. et al., 1998, 358 p.

  7. Proof of concept and performance optimization of high gravity batch-type centrifugal dryer for dewatering fine coal

    SciTech Connect

    Smith, L.B.; Durney, T.

    1991-01-01

    The primary objective of the project was to assemble, analyze and make use of those data that could help to clearly identify, optimize and confirm the technical and economic advantages that the new high gravity centrifugal dryer technology can provide to the coal industry and to end users. Other objectives were: to confirm the feasibility of the dryer for drying coals from a number of different seams; to use the data base for optimizing the dryer's systems, and: to produce projected technical and economic comparisons with thermal dryers as applied to an existing coal processing plant flow sheet. (JL)

  8. Network congestion analysis of gravity generated models

    NASA Astrophysics Data System (ADS)

    Maniadakis, Dimitris; Varoutas, Dimitris

    2014-07-01

    The network topology has lately proved to be critical to the appearance of traffic congestion, with scale-free networks being the less affected at high volumes of traffic. Here, the congestion dynamics are investigated for a class of networks that has experienced a resurgence of interest, the networks based on the gravity model. In addition, supplementary to the standard paradigm of uniform traffic volumes between randomly interacting node pairs, more realistic gravity traffic patterns are used to simulate the flows in the network. Results indicate that depending on the traffic pattern, the networks have different tolerance to congestion. Experiment simulation shows that the topologies created on the basis of the gravity model suffer less from congestion than the random, the scale-free or the Jackson-Rogers ones under both random and gravity traffic patterns. The congestion level is found to be approximately correlated with the network clustering coefficient in the case of random traffic, whereas in the case of gravity traffic such a correlation is not a trivial one. Other basic network properties such as the average shortest path and the diameter are seen to correlate fairly well with the congestion level. Further investigation on the adjustment of the gravity model parameters indicates particular sensitivity to network congestion. This work may have practical implications for designing traffic networks with both reasonable budget and good performance.

  9. High-Accuracy Measurements of the Centre of Gravity of Avalanches in Proportional Chambers

    DOE R&D Accomplishments Database

    Charpak, G.; Jeavons, A.; Sauli, F.; Stubbs, R.

    1973-09-24

    In a multiwire proportional chamber the avalanches occur close to the anode wires. The motion of the positive ions in the large electric fields at the vicinity of the wires induces fast-rising positive pulses on the surrounding electrodes. Different methods have been developed in order to determine the position of the centre of the avalanches. In the method we describe, the centre of gravity of the pulse distribution is measured directly. It seems to lead to an accuracy which is limited only by the stability of the spatial distribution of the avalanches generated by the process being measured.

  10. Selection from Industrial Lager Yeast Strains of Variants with Improved Fermentation Performance in Very-High-Gravity Worts?

    PubMed Central

    Huuskonen, Anne; Markkula, Tuomas; Vidgren, Virve; Lima, Luis; Mulder, Linda; Geurts, Wim; Walsh, Michael; Londesborough, John

    2010-01-01

    There are economic and other advantages if the fermentable sugar concentration in industrial brewery fermentations can be increased from that of currently used high-gravity (ca. 14 to 17P [degrees Plato]) worts into the very-high-gravity (VHG; 18 to 25P) range. Many industrial strains of brewer's yeast perform poorly in VHG worts, exhibiting decreased growth, slow and incomplete fermentations, and low viability of the yeast cropped for recycling into subsequent fermentations. A new and efficient method for selecting variant cells with improved performance in VHG worts is described. In this new method, mutagenized industrial yeast was put through a VHG wort fermentation and then incubated anaerobically in the resulting beer while maintaining the ?-glucoside concentration at about 10 to 20 gliter?1 by slowly feeding the yeast maltose or maltotriose until most of the cells had died. When survival rates fell to 1 to 10 cells per 106 original cells, a high proportion (up to 30%) of survivors fermented VHG worts 10 to 30% faster and more completely (residual sugars lower by 2 to 8 gliter?1) than the parent strains, but the sedimentation behavior and profiles of yeast-derived flavor compounds of the survivors were similar to those of the parent strains. PMID:20081007

  11. Selection from industrial lager yeast strains of variants with improved fermentation performance in very-high-gravity worts.

    PubMed

    Huuskonen, Anne; Markkula, Tuomas; Vidgren, Virve; Lima, Luis; Mulder, Linda; Geurts, Wim; Walsh, Michael; Londesborough, John

    2010-03-01

    There are economic and other advantages if the fermentable sugar concentration in industrial brewery fermentations can be increased from that of currently used high-gravity (ca. 14 to 17 degrees P [degrees Plato]) worts into the very-high-gravity (VHG; 18 to 25 degrees P) range. Many industrial strains of brewer's yeast perform poorly in VHG worts, exhibiting decreased growth, slow and incomplete fermentations, and low viability of the yeast cropped for recycling into subsequent fermentations. A new and efficient method for selecting variant cells with improved performance in VHG worts is described. In this new method, mutagenized industrial yeast was put through a VHG wort fermentation and then incubated anaerobically in the resulting beer while maintaining the alpha-glucoside concentration at about 10 to 20 g.liter(-1) by slowly feeding the yeast maltose or maltotriose until most of the cells had died. When survival rates fell to 1 to 10 cells per 10(6) original cells, a high proportion (up to 30%) of survivors fermented VHG worts 10 to 30% faster and more completely (residual sugars lower by 2 to 8 g.liter(-1)) than the parent strains, but the sedimentation behavior and profiles of yeast-derived flavor compounds of the survivors were similar to those of the parent strains. PMID:20081007

  12. Investigating Zigzag Film Growth Behaviors in Layer-by-Layer Self-Assembly of Small Molecules through a High-Gravity Technique.

    PubMed

    Cheng, Mengjiao; Jiang, Chao; Luo, Caijun; Zhang, Yajun; Shi, Feng

    2015-08-26

    The zigzag film growth behavior in the layer-by-layer (LbL) assembly method is a ubiquitous phenomenon for which the growth mechanism was rarely investigated, especially for small molecules. To interpret the zigzag increasing manner, we hypothesized that the desorption kinetics of small molecules was dominant for the film growth behavior and demonstrated this hypotheis by introducing the high-gravity technique into the LbL assembly of a typical polyelectrolyte/small molecule system of polyethylenimine (PEI) and meso-tetra(4-carboxyphenyl)porphine (Por). The results showed that the high-gravity technique remarkably accelerated the desorption process of Por; the high-gravity LbL assembly provides a good platform to reveal the desorption kinetics of Por, which is tedious to study in conventional situation. We found that as much as 50 min is required for Por molecules to reach desorption equilibrium from the substrate to the bulk PEI solution for the conventional dipping method; however, the process could be accelerated and require only 100 s if a high-gravity field is used. Nonequilibrated desorption at 10 min for normal dipping and at 30 s for high-gravity-field-assisted assembly both exhibited a zigzag film growth, but after reaching desorption equilibrium at 100 s under a high-gravity field, film growth began to cycle between assembly and complete disassembly instead of LbL assembly. For the first time we have proven that the high-gravity technique can also accelerate the desorption process and demonstrated the desorption-dependent mechanism of small molecules for zigzag film growth behaviors. PMID:26258488

  13. 46 CFR 119.530 - Bilge high level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bilge high level alarms. 119.530 Section 119.530... Bilge and Ballast Systems 119.530 Bilge high level alarms. (a) Each vessel must be provided with a visual and audible alarm at the operating station to indicate a high water level in each of the...

  14. 46 CFR 182.530 - Bilge high level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Bilge high level alarms. 182.530 Section 182.530... TONS) MACHINERY INSTALLATION Bilge and Ballast Systems 182.530 Bilge high level alarms. (a) On a... operating station to indicate a high water level in each of the following normally unmanned spaces: (1)...

  15. 46 CFR 119.530 - Bilge high level alarms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Bilge high level alarms. 119.530 Section 119.530... Bilge and Ballast Systems 119.530 Bilge high level alarms. (a) Each vessel must be provided with a visual and audible alarm at the operating station to indicate a high water level in each of the...

  16. 46 CFR 153.409 - High level alarms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false High level alarms. 153.409 Section 153.409 Shipping... Systems 153.409 High level alarms. When Table 1 refers to this section or requires a cargo to have a closed gauging system, the cargo's containment system must have a high level alarm: (a) That gives...

  17. 46 CFR 153.409 - High level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false High level alarms. 153.409 Section 153.409 Shipping... Systems 153.409 High level alarms. When Table 1 refers to this section or requires a cargo to have a closed gauging system, the cargo's containment system must have a high level alarm: (a) That gives...

  18. 46 CFR 182.530 - Bilge high level alarms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Bilge high level alarms. 182.530 Section 182.530... TONS) MACHINERY INSTALLATION Bilge and Ballast Systems 182.530 Bilge high level alarms. (a) On a... operating station to indicate a high water level in each of the following normally unmanned spaces: (1)...

  19. Kelvin and Rossby gravity wave packets in the lower stratosphere of some high-top CMIP5 models

    NASA Astrophysics Data System (ADS)

    Lott, Francois; Denvil, Sbastien; Butchard, Neal; Cagnazzo, Chiara; Giorgetta, Marco; Hardiman, Steven; Manzini, Elisa; Krismer, Thomas; Duvel, Jean-Philippe; Maury, Pauline; Scinocca, John

    2015-04-01

    We analyse the stratospheric Kelvin and Rossby-gravity wave packets with periods of a few days in nine high-top (i.e. with stratosphere) models of the fifth Coupled Model Intercomparison Project (CMIP5). These models simulate realistic aspects of these waves, and represent them better than the tropospheric convectively coupled waves analyzed in previous studies. There is nevertheless a large spread among the models, and those with a Quasi-biennial Oscillation (QBO) produce larger amplitude waves than the models without a QBO. For the Rossby-gravity waves this is explained by the fact that models without a QBO never have positive zonal mean zonal winds in the lower stratosphe re, a situation that is favorable to the propagation of Rossby-gravity waves. For the Kelvin waves, larger amplitudes in the presence of a QBO is counter intuitive because Kelvin waves are expected to have larger amplitude when the zonal mean zonal wind is negative, and this is always satisfied in models without a QBO. We attribute the larger amplitude to the fact that models tuned to have a QBO require finer vertical resolution in the stratosphere. We also find that models with large precipitation variability tend to produce larger amplitude waves. However, the effect is not as pronounced as was found in previous studies. In fact, even models with weak precipitation variability still have quite realistic stratospheric waves, indicating either that (i) other sources can be significant or that (ii) the dynamical filtering mitigates the differences in the sources between models.

  20. Infrared Thermography in High Level Waste

    SciTech Connect

    GLEATON, DAVIDT.

    2004-08-24

    The Savannah River Site is a Department of Energy, government-owned, company-operated industrial complex built in the 1950s to produce materials used in nuclear weapons. Five reactors were built to support the production of nuclear weapons material. Irradiated materials were moved from the reactors to one of the two chemical separation plants. In these facilities, known as ''canyons,'' the irradiated fuel and target assemblies were chemically processed to separate useful products from waste. Unfortunately, the by-product waste of nuclear material production was a highly radioactive liquid that had to be stored and maintained. In 1993 a strategy was developed to implement predictive maintenance technologies in the Liquid Waste Disposition Project Division responsible for processing the liquid waste. Responsibilities include the processing and treatment of 51 underground tanks designed to hold 750,000 to1,300,000 gallons of liquid waste and operation of a facility that vitrifies highly radioactive liquid waste into glass logs. Electrical and mechanical equipment monitored at these facilities is very similar to that found in non-nuclear industrial plants. Annual inspections are performed on electrical components, roof systems, and mechanical equipment. Troubleshooting and post installation and post-maintenance infrared inspections are performed as needed. In conclusion, regardless of the industry, the use of infrared thermography has proven to be an efficient and effective method of inspection to help improve plant safety and reliability through early detection of equipment problems.

  1. Exploring medium gravity icy planetary bodies: an opportunity in the Inner System by landing at Ceres high latitudes

    NASA Astrophysics Data System (ADS)

    Poncy, J.; Grasset, O.; Martinot, V.; Tobie, G.

    2009-04-01

    With potentially up to 25% of its mass as H2O and current indications of a differentiated morphology, 950km-wide "dwarf planet" Ceres is holding the promise to be our closest significant icy planetary body. Ceres is within easier reach than the icy moons, allowing for the use of solar arrays and not lying inside the deep gravity well of a giant planet. As such, it would represent an ideal step stone for future in-situ exploration of other airless icy bodies of major interest such as Europa or Enceladus. But when NASA's Dawn orbits Ceres and maps it in 2015, will we be ready to undertake the next logical step: landing? Ceres' gravity at its poles, at about one fifth of the Moon's gravity, is too large for rendezvous-like asteroid landing techniques to apply. Instead, we are there fully in the application domain of soft precision landing techniques such as the ones being developed for ESA's MoonNext mission. These latter require a spacecraft architecture akin to robotic lunar Landers or NASA's Phoenix, and differing from missions to comets and asteroids. If Dawn confirms the icy nature of Ceres under its regolith-covered surface, the potential presence of some ice spots on the surface would call for specific attention. Such spots would indeed be highly interesting landing sites. They are more likely to lie close to the poles of Ceres where cold temperatures should prevent exposed ice from sublimating and/or may limit the thickness of the regolith layer. Also the science and instruments suite should be fitted to study a large body that has probably been or may still be geologically active: its non-negligible gravity field combined with its high volatile mass fraction would then bring Ceres closer in morphology and history to an "Enceladus" or a frozen or near-frozen "Europa" than to a rubble-pile-structured asteroid or a comet nucleus. Thales Alenia Space and the "Laboratoire de Planétologie et Géodynamique" of the University of Nantes have carried out a preliminary assessment of a mission to Ceres high latitudes. We present here why we think an in-situ mission to the polar areas of Ceres should be of interest in the near future. We dwell on the environmental factors and challenges for a Lander, both as specificities of Ceres and as a consequence of the high latitude targeted. Factors such as day duration, fine regolith, terrain hazards, optical contrasts, thermal gradients, planetary contamination... are reviewed. We then assess how the soft precision landing technologies being developed for other missions would apply in such an environment. We present a preliminary mission analysis and a concept for the Lander, with preliminary evaluation of mass and power resources for a fixed payload or for a mini-rover. The resulting mission design combines technological maturity and a launch mass that is found compatible with the moderate cost of a Soyuz launcher. Finally we conclude that a Ceres Polar Lander mission should be feasible, covered by automatic missions to the Moon in terms of difficulty of landing and by Dawn for the cruise. Lander missions to medium gravity bodies such as Ceres, Enceladus, Europa, Ganymede, Callisto, Iapetus, Triton… in the [0.01-0.15g] range should be accounted for in the development roadmaps of landing techniques and be considered in their return on investment. The synergies with the soft landing missions to come on Mars and Moon should then make a Ceres lander affordable for the agencies within the end of the next decade and pave the way for in-situ missions to more distant icy bodies.

  2. Precision gravity detection - Gradiometry and/or radiometry

    NASA Technical Reports Server (NTRS)

    Ananda, M.

    1977-01-01

    Current knowledge concerning the earth's gravity field is limited to about 1500-2000 km resolution. However, the resolution of gravity anomalies having a spatial extent of 100-1000 km over the entire globe is needed for important geophysical and geodetic applications. In the near future satellite altimetry will be used to determine the ocean geoid at the 10 cm - 1 m level. In order to provide a similar level of resolutions over the land regions, there exists a need for utilizing new promising techniques such as gravity gradiometry and new radiometric measurements, viz., satellite-to-satellite tracking. Satellite-to-satellite tracking techniques have shown potential for improving the medium wavelength component of the gravity field. The gravity gradiometer has not yet been tested on board a satellite. The reported analysis includes a simplified theoretical model to compare the effectiveness of the gradiometer measurements and radiometric measurements for high resolution gravity field determination, and the direct estimation of local gravity anomalies represented by point masses using a simulated gravity gradiometer and satellite-to-satellite tracking data.

  3. New Antarctic gravity anomaly grid for enhanced geodetic and geophysical studies in Antarctica

    NASA Astrophysics Data System (ADS)

    Scheinert, M.; Ferraccioli, F.; Schwabe, J.; Bell, R.; Studinger, M.; Damaske, D.; Jokat, W.; Aleshkova, N.; Jordan, T.; Leitchenkov, G.; Blankenship, D. D.; Damiani, T. M.; Young, D.; Cochran, J. R.; Richter, T. D.

    2016-01-01

    Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne, and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated leveling of the different gravity data sets with respect to an Earth gravity model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth gravity models to be derived and represent a major step forward toward solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.

  4. Clear and measurable signature of modified gravity in the galaxy velocity field.

    PubMed

    Hellwing, Wojciech A; Barreira, Alexandre; Frenk, Carlos S; Li, Baojiu; Cole, Shaun

    2014-06-01

    The velocity field of dark matter and galaxies reflects the continued action of gravity throughout cosmic history. We show that the low-order moments of the pairwise velocity distribution v_{12} are a powerful diagnostic of the laws of gravity on cosmological scales. In particular, the projected line-of-sight galaxy pairwise velocity dispersion ?_{12}(r) is very sensitive to the presence of modified gravity. Using a set of high-resolution N-body simulations, we compute the pairwise velocity distribution and its projected line-of-sight dispersion for a class of modified gravity theories: the chameleon f(R) gravity and Galileon gravity (cubic and quartic). The velocities of dark matter halos with a wide range of masses would exhibit deviations from general relativity at the (5-10)? level. We examine strategies for detecting these deviations in galaxy redshift and peculiar velocity surveys. If detected, this signature would be a "smoking gun" for modified gravity. PMID:24949751

  5. Al2O3/ZrO2 (Y2O3) Prepared by Combustion Synthesis Under High Gravity

    NASA Astrophysics Data System (ADS)

    Zhang, Long; Zhao, Zhongmin; Song, Yigang; Wang, Weiguo; Liu, Hongbo

    By introducing ZrO2 (4Y) powder into the thermit, Al2O3/ZrO2 (4Y) composite ceramics of different composition and microstructures were prepared through combustion synthesis under high gravity, and the correlations of composition, microstructures and mechanical properties of composite ceramics were investigated. The results of XRD, SEM and EDS showed that Al2O3/33%ZrO2 (4Y) were composed of random-orientated rod-shaped colonies consisting of a triangular dispersion of orderly submicron-nanometer t-ZrO2 fibers, surrounded by inter-colony regions consisting of spherically-shaped micronmeter t-ZrO2 grains; meanwhile, Al2O3/45%ZrO2 (4Y) were comprised of spherically-shaped micron-meter t-ZrO2 grains. Similar to the international directionally solidified Al2O3/ZrO2 (Y2O3), the EDS results also indicated that there are no impurities, amorphous phases and grain boundaries but clean phase interfaces in two ceramic composites. Compared to the international directionally solidified Al2O3/ZrO2 (Y2O3), the increase in hardness and flexural strength of Al2O3/33%ZrO2 (4Y) in the experiment was due to small-size defect and high fracture toughness induced by compressive residual stress effect and transformation toughening mechanisms; meanwhile, high flexural strength of Al2O3/45%ZrO2 (4Y) was considered to be a result of the fine spherically-shaped t-ZrO2 grains separated from the melt under high gravity, and high fracture toughness induced by transformation toughening and micro-crack toughening mechanisms.

  6. Bumblebee Pupae Contain High Levels of Aluminium

    PubMed Central

    Exley, Christopher; Rotheray, Ellen; Goulson, David

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD) value of 51.0 (33.0) μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer’s disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline. PMID:26042788

  7. Bumblebee pupae contain high levels of aluminium.

    PubMed

    Exley, Christopher; Rotheray, Ellen; Goulson, David

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 ?g/g dry wt. and a mean (SD) value of 51.0 (33.0) ?g/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer's disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline. PMID:26042788

  8. Impacts of Thermal and Wind structures on Mesospheric Short-period Gravity Wave Propagation at High Latitudes

    NASA Astrophysics Data System (ADS)

    Nielsen, Kim; Taylor, Michael J.; Siskind, David; Collins, Richard; Harvey, V. Lynn; Russell, James; Irving, Brita; Negale, Michael

    2012-07-01

    Mesospheric short-period (<1-hr) gravity waves are of great importance for dynamics in the mesosphere-lower thermosphere (MLT) region, and are typically measured by instruments capable of high temporal and/or spatial resolutions, such as lidars and airglow imagers. These waves have been studied extensively at low- and mid-latitudes where known wave sources are well established. The results show strong dependence on the background wind and temperature fields, which can act as a barrier prohibiting vertical propagation of the waves, as well as providing a ducted environment in which the waves can travel large horizontal distances. In fact, results show that up to 75% of these waves may exhibit ducted wave motion. Recent efforts to quantify the existence and nature of these waves over the Antarctic continent have lead to a long-term (10 years) data set obtained with airglow imagers. Our results suggest that these southern polar waves are predominantly freely propagating in the airglow region, in stark contrast to results at other latitudes. A new study in the Arctic enables a comparison between the two data sets. In this work, we investigate the propagation nature of the observed wave field and attempt to identify dominant source regions and potential sources of polar gravity waves through ray tracing.

  9. Future lunar gravity measurements

    NASA Technical Reports Server (NTRS)

    Forward, R. L.

    1980-01-01

    Future missions to the moon should include a detailed high-resolution global gravity survey from a low (15-30 km) polar orbiting spacecraft. The use of gravity gradiometer instruments on board the spacecraft will give higher-resolution data at lower total mission cost than the present Doppler tracking technique. Simulations show that although a three axis gradiometer system is preferred, and can even be used to estimate spacecraft attitude and altitude variation, a properly oriented single rotating gravity gradiometer can be used to resolve closely spaced mascons in both the along-track and cross-track directions.

  10. Gravity waves in Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Friedson, A. James

    1994-05-01

    Scintillations (high frequency variations) observed in the radio signal during the occultation of Voyager 1 by Titan (Hinson and Tyler, 1983) provide information concerning neutral atmospheric density fluctuations on scales on hundreds of meters to a few kilometers. Those seen at altitudes higher than 25 km above the surface were interpreted by Hinson and Tyler as being caused by linear, freely propagating (energy-conserving) gravity waves, but this interpretation was found to be inconsistent with the scintillation data below the 25-km altitude level. Here an attempt is made to interpret the entire scintillation profile between the surface and the 90-km altitude level in terms of gravity waves generated at the surface. Numerical calculations of the density fluctuations caused by two-dimensional, nonhydrostatic, finite-amplitude gravity waves propagating vertically through Titan's atmosphere are performed to produce synthetic scintillation profiles for comparison with the observations. The numerical model accurately treats the effects of wave transience, nonlinearity, and breakdown due to convective instability in the overturned part of the wave. The high-altitude scintillation data were accurately recovered with a freely propagating wave solution, confirming the analytic model of Hinson and Tyler. It is found that the low-altitude scintillation data can be fit by a model where a component of the gravity waves becomes convectively unstable and breaks near the 15 km level. The large-scale structure of the observed scintillation profile in the entire altitude range between 5 and 85 km can be simulated by a model where the freely propagating and breaking waves are forced at the surface simultaneously. Further analysis of the Voyager 1 Titan low-altitude scintillation data, using inversion theory appropriate for strong scattering, could potentially remove some of the ambiguities remaining in this analysis and allow a better determination of the strength and source of the waves.

  11. Gravity waves in Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Friedson, A. James

    1994-01-01

    Scintillations (high frequency variations) observed in the radio signal during the occultation of Voyager 1 by Titan (Hinson and Tyler, 1983) provide information concerning neutral atmospheric density fluctuations on scales on hundreds of meters to a few kilometers. Those seen at altitudes higher than 25 km above the surface were interpreted by Hinson and Tyler as being caused by linear, freely propagating (energy-conserving) gravity waves, but this interpretation was found to be inconsistent with the scintillation data below the 25-km altitude level. Here an attempt is made to interpret the entire scintillation profile between the surface and the 90-km altitude level in terms of gravity waves generated at the surface. Numerical calculations of the density fluctuations caused by two-dimensional, nonhydrostatic, finite-amplitude gravity waves propagating vertically through Titan's atmosphere are performed to produce synthetic scintillation profiles for comparison with the observations. The numerical model accurately treats the effects of wave transience, nonlinearity, and breakdown due to convective instability in the overturned part of the wave. The high-altitude scintillation data were accurately recovered with a freely propagating wave solution, confirming the analytic model of Hinson and Tyler. It is found that the low-altitude scintillation data can be fit by a model where a component of the gravity waves becomes convectively unstable and breaks near the 15 km level. The large-scale structure of the observed scintillation profile in the entire altitude range between 5 and 85 km can be simulated by a model where the freely propagating and breaking waves are forced at the surface simultaneously. Further analysis of the Voyager 1 Titan low-altitude scintillation data, using inversion theory appropriate for strong scattering, could potentially remove some of the ambiguities remaining in this analysis and allow a better determination of the strength and source of the waves.

  12. Lunar gravity field recovery: GRAIL simulation studies

    NASA Astrophysics Data System (ADS)

    Klinger, Beate; Baur, Oliver; Mayer-Grr, Torsten; Yan, Jianguo

    2013-04-01

    The NASA mission GRAIL (Gravity Recovery and Interior Laboratory) makes use of low-low Satellite-to-Satellite Tracking (ll-SST) between the two spacecraft GRAIL-A and GRAIL-B to determine a high-resolution gravity field solution of the Moon. The mission concept is inherited from the GRACE (Gravity Recovery and Climate Experiment) project, a space gravimetry mission mapping the terrestrial gravity field. Since the Moon is in synchronous rotation with the Earth, direct (radio) tracking of the satellites on the farside is impossible, but GRAIL provides global coverage of inter-satellite tracking data. Furthermore, ll-SST observations are much more sensitive to gravitational features than ground-based orbit tracking. Therefore, compared to previous missions, GRAIL enables a more accurate estimation of the lunar gravity field, with a much higher spectral and spatial resolution. The accurate knowledge of the lunar nearside and farside gravity is essential to improve the understanding of the Moon's interior structure and its thermal evolution. We conducted a series of sensitivity studies based on simulated orbit information (positions) and ll-SST measurements (ranges, range rates, range accelerations). Observations are simulated on the nearside as well as on the farside (1) during the time span of the GRAIL science phase, (2) for different orbit altitudes and varying separation distances, (3) for different orbit/ll-SST noise levels. Based on the simulated observations the spherical harmonic coefficients, which represent the lunar gravity field, are estimated using an integral equation approach. Observation simulation and parameter estimation is accomplished using the GROOPS (Gravity Recovery Object Orientated Programming System) software package.

  13. Analysis of Cyberbullying Sensitivity Levels of High School Students and Their Perceived Social Support Levels

    ERIC Educational Resources Information Center

    Akturk, Ahmet Oguz

    2015-01-01

    Purpose: The purpose of this paper is to determine the cyberbullying sensitivity levels of high school students and their perceived social supports levels, and analyze the variables that predict cyberbullying sensitivity. In addition, whether cyberbullying sensitivity levels and social support levels differed according to gender was also

  14. Analysis of Cyberbullying Sensitivity Levels of High School Students and Their Perceived Social Support Levels

    ERIC Educational Resources Information Center

    Akturk, Ahmet Oguz

    2015-01-01

    Purpose: The purpose of this paper is to determine the cyberbullying sensitivity levels of high school students and their perceived social supports levels, and analyze the variables that predict cyberbullying sensitivity. In addition, whether cyberbullying sensitivity levels and social support levels differed according to gender was also…

  15. Lunar gravity - Apollo 16

    NASA Technical Reports Server (NTRS)

    Sjogren, W. L.; Wimberly, R. N.; Wollenhaupt, W. R.

    1974-01-01

    Reduction of Doppler radio tracking of the orbiting spacecraft has shown consistency with Apollo 14 data results and has revealed new gravity anomalies. Large craters are negative anomalies while wrinkle ridge regions are positive. The Central highlands are mostly a positive anomaly except for the Apollo 16 landing site, which is in a negative area. A gravity high northwest of Theophilus is not easily explained.

  16. High frequency gravity waves observed in OH airglow at Starfire Optical Range, NM: Seasonal variations in momentum flux

    NASA Astrophysics Data System (ADS)

    Tang, Jing; Liu, Alan Z.; Swenson, Gary R.

    2002-10-01

    Airglow imager and Na wind/temperature lidar measurements at Starfire Optical Range, New Mexico (35°N, 107°W) are used to estimate the seasonal variation of the vertical fluxes of horizontal momentum carried by high frequency Atmospheric Gravity Waves (AGWs). The cross-correlation coefficients between the vertical and horizontal wind perturbations were calculated from the OH airglow imager data collected during 32 nights in 1998, 1999 and 2000. The RMS wind velocities were deduced from the lidar measurements. The combined information was used to estimate the upper limit of the momentum flux. The meridional component of the vertical flux of horizontal momentum was observed to be towards the summer pole. The zonal component had westward preference in winter and weak preference in summer. The unanticipated large meridional component may act to regulate the summer to winter circulation in the mesosphere.

  17. A global view of gravity waves in the Martian atmosphere inferred from a high-resolution general circulation model

    NASA Astrophysics Data System (ADS)

    Kuroda, Takeshi; Medvedev, Alexander S.; Yi?it, Erdal; Hartogh, Paul

    2015-11-01

    Global characteristics of the small-scale gravity wave (GW) field in the Martian atmosphere obtained from a high-resolution general circulation model (GCM) are presented for the first time. The simulated GW-induced temperature variances are in a good agreement with available radio occultation data in the lower atmosphere between 10 and 30 km. The model reveals a latitudinal asymmetry with stronger wave generation in the winter hemisphere and two distinctive sources of GWs: mountainous regions and the meandering winter polar jet. Orographic GWs are filtered, while propagating upward, and the mesosphere is primarily dominated by harmonics with faster horizontal phase velocities. Wave fluxes are directed mainly against the local wind. GW dissipation in the upper mesosphere generates body forces of tens of m s-1 per Martian solar day (sol-1), which tend to close the simulated jets. The results represent a realistic surrogate for missing observations, which can be used for constraining GW parameterizations and validating GCM simulations.

  18. Effects of Body Orientation and Retinal Image Pitch on the Perception of Gravity-Referenced Eye Level (GREL)

    NASA Technical Reports Server (NTRS)

    Cohen, Malcolm M.; Guzy, Larry T.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    It has been asserted that the pitch orientation of a visual array and of an observer's body jointly determine the perception of GREL. The current study formally tests this assertion over an extended range with multiple combinations of visual and body pitch orientations. Ten subjects were individually secured in a Circolectric bed surrounded by a room (pitchroom) with walls that could be pitched at various angles with respect to gravity. The bed and the walls of the room were independently adjusted to each of five positions relative to gravitational vertical: -15, -7.5, 0, +7.5, and +15 degrees, yielding 25 combinations of body x room pitch angles, and retinal image pitch (RIP) conditions ranging from -30 to +30 degrees. Each subject set a target to apparent GREL while viewing it against a background of two electroluminescent strips on the outer edges of the far wall of the room. As determined by ANOVA, the orientation of the room, and its interaction with that of the observer, significantly altered GREL (p less than 0.01). Regression analysis showed that GREL was best described as a linear summation of the weighted independent contributions from a body-referenced mechanism (B) and a visual mechanism given by the orientation of the background array on the retina (RIP). The equation for this relationship is: GREL = .74 (B) +.64 (RIP) - 1.42; r-squared = .994.

  19. GOCE gravity field models following the time-wise approach

    NASA Astrophysics Data System (ADS)

    Brockmann, Jan Martin; Höck, Eduard; Loth, Ina; Mayer-Gürr, Torsten; Pail, Roland; Schuh, Wolf-Dieter; Zehentner, Norbert

    2015-04-01

    Since the launch of the European Space Agency's (ESA) Gravity field and Ocean Circulation Explorer (GOCE) satellite in 2009 and its end in 2013, a sequence of official GOCE gravity field models was released. One of the series of models follows the so called time-wise approach (EGM_TIM). They are purely based on GOCE observations such that they are independent of any other gravity field information available and describe the Earth's gravity field as seen by GOCE. Recently, the fifth release, EGM_TIM_RL05, was computed and made available to users. The models of the time-wise series were computed within the ESA funded High-level Processing Facility (HPF) and are part of the official ESA GOCE products. Calibrated gravity gradients in the gradiometer reference frame and the satellites position as derived by GPS measurements entered the solutions as observations. Together with the spherical harmonic coefficients, a realistic the full covariance matrix is provided reflecting the model quality. This contribution summarizes the gravity field models derived with the time-wise approach. The method is summarized and the progress along the five releases is highlighted. Special focus is put on the final release 5, the gravity field model which includes all data collected during the entire GOCE mission. This model, parametrized as 78,957 spherical harmonic coefficients (spatial resolution of 71 km), was determined from 4*109,799,264 gravity gradient measurements and 108,754,709 three dimensional positions within a joint least squares adjustment procedure. As this gravity field models only depend on GOCE observations, the gain of GOCE compared to other missions and other gravity field products can be clearly demonstrated. With release 5 of the time-wise model, a pure GOCE based model with a mean global accuracy of 2.4 cm at a spatial resolution of 100 km for the geoid is available (0.7 mGal for gravity anomalies).

  20. Cascading gravity is ghost free

    SciTech Connect

    Rham, Claudia de; Khoury, Justin; Tolley, Andrew J.

    2010-06-15

    We perform a full perturbative stability analysis of the 6D cascading gravity model in the presence of 3-brane tension. We demonstrate that for sufficiently large tension on the (flat) 3-brane, there are no ghosts at the perturbative level, consistent with results that had previously only been obtained in a specific 5D decoupling limit. These results establish the cascading gravity framework as a consistent infrared modification of gravity.

  1. Basement Aquifers : How Useful Are Gravity Data ?

    NASA Astrophysics Data System (ADS)

    Genthon, P.; Mouhouyouddine, A. H.; Hinderer, J.; Hector, B.; Yameogo, S.

    2014-12-01

    Gravity data with a few microgal precision were proved to be able to constrain the specific yield of various kinds of aquifer in West Africa from annual fluctuations of both the gravimetric and piezometric signals (Pfeffer et al., Geophys. J. Int., 2011; Hector et al., Geophys. J. Int., 2013). However some recent papers reported a disappointing potential of gravity measurements during a pumping experiment in a sandy aquifer (Blainey et al., WRR, 2007; Herckenrath et al., WRR, 2012) and their poor ability in constraining the transmissity and specific yield of the aquifer, which are the parameters to which pumping tests give access. Fresh basement rocks present generally a null porosity and the structure of basement aquifers is given by the weathering profile. In tropical climate, this profile consists of a few tens meter thick saprolite layer, with noticeable porosity but low permeability overlying the weathering front. This weathering front includes in many instances a fractured medium and presents a high permeability with variable porosity. It is hardly sampled in coring experiments. We present some numerical simulation results on the ability of gravity to constrain the transmissivity of this medium. Due to poroelasticity of clay minerals in the saprolite, soil subsidence is expected to occur during pumping with a significant gravity effect. Gravity measurements have therefore to be completed with leveling data at a millimetric precision. We present first the results of numerical modeling of the gravity and subsidence for a theoretical horizontally stratified basement aquifer, and show that gravity and leveling are able to provide independently the poroelasticity coefficient and a single transmissivity coefficient for the bottom of the aquifer, if the properties of the upper saprolites are known. We will discuss then the general case, where the aquifer presents a vertical fracture where the weathering profile thickens.

  2. DOE HIGH-LEVEL VITRIFIED WASTE DOSE CALCULATION

    SciTech Connect

    J.A. Ziegler

    1999-08-26

    The purpose of this engineering calculation is to provide the radiological dose at 5,000 meters from the surface facilities of the Monitored Geologic Repository (MGR) resulting from a drop of one High-Level Waste (HLW) canister containing vitrified high-level waste glass during handling operations in the Waste Handling Building (WHB). High-level vitrified wastes from Savannah River Site (SRS), Hanford Works, West Valley, New York, and Idaho National Engineering and Environmental Laboratory (INEEL) are evaluated. This calculation will provide input data for future safety analyses for handling of Department of Energy (DOE) high-level waste in the MGR.

  3. Gravity model studies of Newberry Volcano, Oregon

    SciTech Connect

    Gettings, M.E.; Griscom, A.

    1988-09-10

    Newberry, Volcano, a large Quaternary volcano located about 60 km east of the axis of the High Cascades volcanoes in central Oregon, has a coincident positive residual gravity anomaly of about 12 mGals. Model calculations of the gravity anomaly field suggest that the volcano is underlain by an intrusive complex of mafic composition of about 20-km diameter and 2-km thickness, at depths above 4 km below sea level. However, uplifted basement in a northwest trending ridge may form part of the underlying excess mass, thus reducing the volume of the subvolcanic intrusive. A ring dike of mafic composition is inferred to intrude to near-surface levels along the caldera ring fractures, and low-density fill of the caldera floor probably has a thickness of 0.7--0.9 km. The gravity anomaly attributable to the volcano is reduced to the east across a north-northwest trending gravity anomaly gradient through Newberry caldera and suggests that normal, perhaps extensional, faulting has occurred subsequent to caldera formation and may have controlled the location of some late-stage basaltic and rhyolitic eruptions. Significant amounts of felsic intrusive material may exist above the mafic intrusive zone but cannot be resolved by the gravity data.

  4. Interactions between Artificial Gravity, the Affected Physiological Systems, and Nutrition

    NASA Technical Reports Server (NTRS)

    Heer, Martina; Baecker, Nathalie; Zwart, Sara; Smith, Scott

    2006-01-01

    Malnutrition, either by insufficient supply of some nutrients or by overfeeding, has a profound effect on the health of an organism. Therefore, optimal nutrition is a necessity in normal gravity on Earth, in microgravity, and when applying artificial gravity to the human system. Reduced physical activity, such as observed in microgravity or bed rest, has an effect on many physiological systems, such as the cardiovascular, musculoskeletal, immune, and body fluids regulation systems. There is currently no countermeasure that is effective to counteract both the cardiovascular and musculoskeletal deconditioning when applied for a short duration (see Chapter 1). Artificial gravity therefore seems the simplest physiological approach to keep these systems intact. The application of intermittent daily dose of artificial gravity by means of centrifugation has often been proposed as a potential countermeasure against the physiological deconditioning induced by spaceflight. However, neither the optimal gravity level, nor its optimal duration of exposure have been enough studied to recommend a validated, effective, and efficient artificial gravity application. As discussed in previous chapters, artificial gravity has a very high potential to counteract any changes caused by reduced physical activity. The nutrient supply, which ideally should match the actual needs, will interact with these changes and therefore has also to be taken into account. This chapter reviews the potential interactions between these nutrients (energy intake, vitamins, minerals) and the other physiological systems affected by artificial gravity generated by an on-board short-radius centrifuge.

  5. High Resolution Simulation of Gravity Currents and Internal Bores on the Continental Shelf

    NASA Astrophysics Data System (ADS)

    Piacsek, S.; Gallacher, P.; Dietrich, D.

    2003-12-01

    The propagation of gravity currents and internal bores was investigated over the flat and sloping portions of the continental shelf. The generation of the bores was effected by the collapse of a lock-exchange configuration, with the heavier fluid initially in the shallow region. Interest was focused on the 5-50 km coastal dynamic scales, as many motions on these scales exhibited nonhydrostatic effects. Model resolutions ranged from 1-5 m in the vertical and 1 to 50 m in the horizontal. Besides the standard shallow ocean (H) and standard nonhydrostatic (NH) deep convection models, we also examined a type of so-called quasi-hydrostatic (QH) model in which the vertical pressure gradient is balanced by a sum of the buoyancy and inertial terms. The final vertical velocity and pressure are determined by an iteration procedure. The simulated Froude numbers and Richardson numbers agreed within 10 % of those found in applicable laboratory experiments. In general, the NH models tended to exhibit the full spectrum and amplitude of the Kelvin-Helmholtz (K-H) instabilities that grow on the plume- ambient fluid interface, and treated the advancing bore front and the rotor situated behind it correctly. The QH model developed K-H instabilities for smaller diffusivities and further back behind the front, with little rotor action behind the bore edge. Both the NH and QH models were found to be sensitive to the grid ratio r = dx/dz and behaved like hydrostatic models for r > 5. In addition, all three classes of models have exhibited strong sensitivity to the size of the time step and diffusivity.

  6. High-gravity-assisted pulsed laser ablation system for the fabrication of functionally graded material thin film.

    PubMed

    Nishiyama, T; Morinaga, S; Nagayama, K

    2009-03-01

    This paper describes a novel method for the fabrication of a thin film deposited on an appropriate substrate having a continuous composition gradient. The composition gradient was achieved by a combination of pulsed laser ablation (PLA) of the target material with a very strong acceleration field generated on a moving disk rotating at a very high speed. The PLA process was used to produce a cloud of high-energy particles of the target material that will be deposited on a substrate placed on the rotating disk. After deposition, the particles will diffuse on the surface of the thin film under a strong acceleration field. The high energy of the particles and their diffusion on the substrate surface in a high-vacuum environment produces a macroscopic composition distribution in the thin film. We have constructed an experimental apparatus consisting of a vacuum chamber in which a circular disk made of titanium is driven by a high-frequency inductive motor. An acceleration field of up to 10,000 G can be generated by this apparatus. Functionally graded material thin films of FeSi(2) with a continuous concentration gradient were successfully fabricated by this method under a gravity field of 5400 G. A significant advantage of this method is that it allows us to fabricate graded thin films with a very smooth surface covered by few droplets. PMID:19334931

  7. A Framework for Translating a High Level Security Policy into Low Level Security Mechanisms

    NASA Astrophysics Data System (ADS)

    Hassan, Ahmed A.; Bahgat, Waleed M.

    2010-01-01

    Security policies have different components; firewall, active directory, and IDS are some examples of these components. Enforcement of network security policies to low level security mechanisms faces some essential difficulties. Consistency, verification, and maintenance are the major ones of these difficulties. One approach to overcome these difficulties is to automate the process of translation of high level security policy into low level security mechanisms. This paper introduces a framework of an automation process that translates a high level security policy into low level security mechanisms. The framework is described in terms of three phases; in the first phase all network assets are categorized according to their roles in the network security and relations between them are identified to constitute the network security model. This proposed model is based on organization based access control (OrBAC). However, the proposed model extend the OrBAC model to include not only access control policy but also some other administrative security policies like auditing policy. Besides, the proposed model enables matching of each rule of the high level security policy with the corresponding ones of the low level security policy. Through the second phase of the proposed framework, the high level security policy is mapped into the network security model. The second phase could be considered as a translation of the high level security policy into an intermediate model level. Finally, the intermediate model level is translated automatically into low level security mechanism. The paper illustrates the applicability of proposed approach through an application example.

  8. Monthly gravity field models derived from GRACE Level 1B data using a modified short-arc approach

    NASA Astrophysics Data System (ADS)

    Chen, Qiujie; Shen, Yunzhong; Zhang, Xingfu; Hsu, Houze; Chen, Wu; Ju, Xiaolei; Lou, Lizhi

    2015-03-01

    In this study, a new time series of Gravity Recovery and Climate Experiment (GRACE) monthly solutions, complete to degree and order 60 spanning from January 2003 to August 2011, has been derived based on a modified short-arc approach. Our models entitled Tongji-GRACE01 are available on the website of International Centre for Global Earth Models http://icgem.gfz-potsdam.de/ICGEM/. The traditional short-arc approach, with no more than 1 h arcs, requires the gradient corrections of satellite orbits in order to reduce the impact of orbit errors on the final solution. Here the modified short-arc approach has been proposed, which has three major differences compared to the traditional one: (1) All the corrections of orbits and range rate measurements are solved together with the geopotential coefficients and the accelerometer biases using a weighted least squares adjustment; (2) the boundary position parameters are not required; and (3) the arc length can be extended to 2 h. The comparisons of geoid degree powers and the mass change signals in the Amazon basin, the Antarctic, and Antarctic Peninsula demonstrate that our model is comparable with the other existing models, i.e., the Centre for Space Research RL05, Jet Propulsion Laboratory RL05, and GeoForschungsZentrum RL05a models. The correlation coefficients of the mass change time series between our model and the other models are better than 0.9 in the Antarctic and Antarctic Peninsula. The mass change rates in the Antarctic and Antarctic Peninsula derived from our model are -92.7 ± 38.0 Gt/yr and -23.9 ± 12.4 Gt/yr, respectively, which are very close to those from other three models and with similar spatial patterns of signals.

  9. The 3-D motion of the centre of gravity of the human body during level walking. II. Lower limb amputees.

    PubMed

    Tesio, L; Lanzi, D; Detrembleur, C

    1998-03-01

    OBJECTIVE: To analyse the motion of the centre of gravity (CG) of the body during gait in unilateral lower limb amputees with good kinematic patterns. DESIGN: Three transtibial (below-knee, BK) and four transfemoral (above-knee, AK) amputees were required to perform successive walks over a 2.4 m long force plate, at freely chosen cadence and speed. BACKGROUND: In previous studies it has been shown that in unilateral lower limb amputee gait, the motion of the CG can be more asymmetric than might be suspected from kinematic analysis. METHODS: The mechanical energy changes of the CG due to its motion in the vertical, forward and lateral direction were measured. Gait speed ranged 0.75-1.32 m s(-1) in the different subjects. This allowed calculation of (a) the positive work done by muscles to maintain the motion of the CG with respect to the ground ('external' work, W(ext)) and (b) the amount of the pendulum-like, energy-saving transfer between gravitational potential energy and kinetic energy of the CG during each step (percent recovery, R). Step length and vertical displacement of the CG were also measured. RESULTS: The recorded variables were kept within the normal limits, calculated in a previous work, when an average was made of the steps performed on the prosthetic (P) and on the normal (N) limb. Asymmetries were found, however, between the P and the N step. In BK amputees, the P step R was 5% greater and W(ext) was 21% lower than in the N step; in AK amputees, in the P step R was 54% greater and W(ext) was 66% lower than in the N step. Asymmetries were also found in the relative magnitude of the external work provided by each lower limb during the single stance as compared with the double stance: a marked deficit of work occurred at the P to N transition. PMID:11415775

  10. Transient increase in the transcript levels of gamma-tubulin complex genes during reorientation of cortical microtubules by gravity in azuki bean (Vigna angularis) epicotyls.

    PubMed

    Soga, Kouichi; Kotake, Toshihisa; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki

    2008-09-01

    By hypergravity treatment, the percentage of cells with transverse microtubules was decreased, while that with longitudinal microtubules was increased in azuki bean (Vigna angularis) epicotyls. The expression of genes encoding gamma-tubulin complex (VaTUG and VaGCP3) was increased transiently in response to changes in the gravitational conditions. Lanthanum and gadolinium ions, potential blockers of mechanosensitive calcium ion-permeable channels (mechanoreceptors), nullified reorientation of microtubules as well as up-regulation of expression of VaTUG and VaGCP3 by hypergravity. These results suggest that mechanoreceptors may perceive the gravity signal, which leads to a transient increase in the transcript levels of gamma-tubulin complex genes and reorientation of cortical microtubules. PMID:18661197

  11. Geographic distribution of zonal wind and UV albedo at cloud top level from VMC camera on Venus Express: Influence of Venus topography through stationary gravity waves vertical propagation

    NASA Astrophysics Data System (ADS)

    Bertaux, J.-L.; Khatunstsev, I. V.; Hauchecorne, A.; Markiewicz, W.; Marcq, E.; Lebonnois, S.; Patsaeva, M. V.; Turin, A. V.

    2015-10-01

    Based on the analysis of UV images (at 365 nm) of Venus cloud top collected with VMC camera on board Venus Express[4,5], it is found that the zonal wind speed south of the equator (from 5°S to 15°s) shows a conspicuous variation with geographic longitude of Venus, correlated with underlying relief of Aphrodite Terra. We interpret this pattern as the result of stationary gravity waves produced at ground level by the up lift of air when the horizontal wind encounters a mountain slope. The cloud albedo map at 365 nm varies also in longitude and latitude, perhaps the result of increased vertical mixing associated to wave breaking, and decreased abundance of the UV absorber which makes the contrast in images.

  12. Gravity brake

    DOEpatents

    Lujan, Richard E. (Santa Fe, NM)

    2001-01-01

    A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.

  13. Magma and fluid migration at Yellowstone Caldera in the last three decades inferred from InSAR, leveling, and gravity measurements

    NASA Astrophysics Data System (ADS)

    Tizzani, P.; Battaglia, M.; Castaldo, R.; Pepe, A.; Zeni, G.; Lanari, R.

    2015-04-01

    We studied the Yellowstone caldera geological unrest between 1977 and 2010 by investigating temporal changes in differential Interferometric Synthetic Aperture Radar (InSAR), precise spirit leveling and gravity measurements. The analysis of the 1992-2010 displacement time series, retrieved by applying the SBAS InSAR technique, allowed the identification of three areas of deformation: (i) the Mallard Lake (ML) and Sour Creek (SC) resurgent domes, (ii) a region close to the Northern Caldera Rim (NCR), and (iii) the eastern Snake River Plain (SRP). While the eastern SRP shows a signal related to tectonic deformation, the other two regions are influenced by the caldera unrest. We removed the tectonic signal from the InSAR displacements, and we modeled the InSAR, leveling, and gravity measurements to retrieve the best fitting source parameters. Our findings confirmed the existence of different distinct sources, beneath the brittle-ductile transition zone, which have been intermittently active during the last three decades. Moreover, we interpreted our results in the light of existing seismic tomography studies. Concerning the SC dome, we highlighted the role of hydrothermal fluids as the driving force behind the 1977-1983 uplift; since 1983-1993 the deformation source transformed into a deeper one with a higher magmatic component. Furthermore, our results support the magmatic nature of the deformation source beneath ML dome for the overall investigated period. Finally, the uplift at NCR is interpreted as magma accumulation, while its subsidence could either be the result of fluids migration outside the caldera or the gravitational adjustment of the source from a spherical to a sill-like geometry.

  14. Physical Activity Levels in Portuguese High School Physical Education

    ERIC Educational Resources Information Center

    Marmeleira, Jose Francisco Filipe; Aldeias, Nuno Micael Carrasqueira; da Graca, Pedro Miguel dos Santos Medeira

    2012-01-01

    The main aim of this study was to evaluate the physical activity (PA) levels of high school Portuguese students during physical education (PE) and investigate the association of PA levels with students' goal orientation and intrinsic motivation. Forty-six students from three high schools participated. Heart rate telemetry and pedometry were used

  15. Predictors of Placement in Lower Level versus Higher Level High School Mathematics

    ERIC Educational Resources Information Center

    Archbald, Doug; Farley-Ripple, Elizabeth N.

    2012-01-01

    Educators and researchers have long been interested in determinants of access to honors level and college prep courses in high school. Factors influencing access to upper level mathematics courses are particularly important because of the hierarchical and sequential nature of this subject and because students who finish high school with only lower

  16. High temperature testing of the EDCON borehole gravity housing system conducted at Los Alamos National Laboratories, January 12-18, 1986

    SciTech Connect

    Not Available

    1986-01-01

    A series of tests were conducted on the EDCON borehole gravity meter (BHGM) high temperature sonde. The tests were conducted to determine the suitability of this sonde for logging operations in the Department of Energy Salton Trough test well. 1 ref., 3 figs., 4 tabs.

  17. Using continuous GPS and absolute gravity to separate vertical land movements and changes in sea-level at tide-gauges in the UK.

    PubMed

    Teferle, F N; Bingley, R M; Williams, S D P; Baker, T F; Dodson, A H

    2006-04-15

    Researchers investigating climate change have used historical tide-gauge measurements from all over the world to investigate the changes in sea-level that have occurred over the last century or so. However, such estimates are a combination of any true sea-level variations and any vertical movements of the land at the specific tide-gauge. For a tide- gauge record to be used to determine the climate related component of changes in sea-level, it is therefore necessary to correct for the vertical land movement component of the observed change in sea-level.In 1990, the Institute of Engineering Surveying and Space Geodesy and Proudman Oceanographic Laboratory started developing techniques based on the Global Positioning System (GPS) for measuring vertical land movements (VLM) at tide-gauges in the UK. This paper provides brief details of these early developments and shows how they led to the establishment of continuous GPS (CGPS) stations at a number of tide-gauges. The paper then goes on to discuss the use of absolute gravity (AG), as an independent technique for measuring VLM at tide-gauges. The most recent results, from CGPS time-series dating back to 1997 and AG time-series dating back to 1995/1996, are then used to demonstrate the complementarity of these two techniques and their potential for providing site-specific estimates of VLM at tide-gauges in the UK. PMID:16537148

  18. Induced gravity Mars transportation systems configuration and hardware penalties

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Fowler, Robert; Appleby, Matthew

    1991-01-01

    The need for an induced gravity environment in-transit to Mars is assessed based on current knowledge. Two possible alternatives to constant in-transit spinning, periodic spinning and Mars surface reconditioning are discussed and compared. Four propulsion options: cryogenic/aerobraking, solid core nuclear thermal, solar electric and nuclear electric are evaluated for concept adaptability to induced gravity, and salient differences from their microgravity counterparts are assessed. Configurations to the systems level are presented and accompanied by mass estimates. Hardware subsystems required for induced gravity vehicles, such as tether crawlers, tether reels, high-power roll-ring assemblies, etc., have been defined to a sufficient level of detail to confidently determine mass penalties. Results of this study show the mass penalties and complexity involved in producing an induced gravity environment.

  19. Born-Infeld-Horava gravity

    SciTech Connect

    Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram

    2010-05-15

    We define various Born-Infeld gravity theories in 3+1 dimensions which reduce to Horava's model at the quadratic level in small curvature expansion. In their exact forms, our actions provide z{yields}{infinity} extensions of Horava's gravity, but when small curvature expansion is used, they reproduce finite z models, including some half-integer ones.

  20. Lunar gravity gradiometry and requirement analysis

    NASA Astrophysics Data System (ADS)

    Cai, Lin; Zhou, Zebing; Gao, Fang; Luo, Jun

    2013-08-01

    The current lunar gravity field models are mostly concluded from lunar exploration programs either by observations of satellite orbit perturbations or by intersatellite ranging and ranging rate measurements between two low-orbiting spacecrafts. Especially, the measurements from the Gravity Recovery and Interior Laboratory (GRAIL) have been used to produce the Moons gravity field models with spatial resolutions up to spherical harmonic degree 420 and 660 for the primary mission and extended mission, respectively. This paper presents a method using satellite gravity gradiometry, which not only can determine a moons gravity field model with a higher resolution, but also can obtain the medium and short wavelength components information with a higher accuracy. This advantage is still obvious in comparison with the results from GRAILs extended mission even though the maximum degree of the model derived from the mission is close to that achieved by the satellite gradiometry discussed in this study. Based on the simulations and analysis, a mission with the hypothesis of an orbit height of about 20 km, a mission duration of about 14 days, and a gradiometer accuracy level of about 30 mE/?{Hz} is proposed, and it permits determination of a lunar gravity field model with a high accuracy of 14 mGal and a geoid with an accuracy of 20.5 cm, both at a spatial resolution of 7 km, corresponding to spherical harmonic degree and order 789. The effects of gravity gradient measurement errors, orbit height, tracking accuracy, mission duration and sampling rate are analytically investigated by the direct relationship between the satellite gravimetry measurements and coefficients of the Moons gravitational potential, which is verified by the least-squares method.

  1. Partial gravity - Human impacts on facility design

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Moore, Nathan

    1990-01-01

    Partial gravity affects the body differently than earth gravity and microgravity environments. The main difference from earth gravity is human locomotion; while the main dfference from microgravity is the specific updown orientation and reach envelopes which increase volume requirements. Much data are available on earth gravity and microgravity design; however, very little information is available on human reactions to reduced gravity levels in IVA situations (without pressure suits). Therefore, if humans commit to permanent lunar habitation, much research should be conducted in the area of partial gravity effects on habitat design.

  2. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1990-01-01

    The scope of the study is to investigate ways of controlling the microgravity environment of the International Space Station by means of a tethered system. Four main study tasks were performed. First, researchers analyzed the utilization of the tether systems to improve the lowest possible steady gravity level on the Space Station and the tether capability to actively control the center of gravity position in order to compensate for activities that would upset the mass distribution of the Station. The purpose of the second task was to evaluate the whole of the experiments performable in a variable gravity environment and the related beneficial residual accelerations, both for pure and applied research in the fields of fluid, materials, and life science, so as to assess the relevance of a variable g-level laboratory. The third task involves the Tethered Variable Gravity Laboratory. The use of the facility that would crawl along a deployed tether and expose experiments to varying intensities of reduced gravity is discussed. Last, a study performed on the Attitude Tether Stabilizer concept is discussed. The stabilization effect of ballast masses tethered to the Space Station was investigated as a means of assisting the attitude control system of the Station.

  3. Regeneration of eye tissues is modulated by altered levels of gravity at 1g, 2g, and in microgravity during spaceflight

    NASA Astrophysics Data System (ADS)

    Grigoryan, Eleonora; Almeida, Eduardo; Mitashov, Victor

    The pursuit of human space exploration requires detailed knowledge of microgravity-related changes in fundamental biological processes, and their effects on health. Normal regeneration of organs and tissues is one such fundamental process that allows maintenance of vitality and function of living organisms. Animal models of tissue regeneration include the newt (Pleurodeles waltl, Urodela) eye, which has been extensively used by our team in Russian Bion and Foton microgravity experiments since 1985, and in recent NASA 2.5 meter diameter centrifuge hypergravity experiments. In total, these experiments allow us to draw several broad conclusions: Newt lens regeneration is significantly altered in microgravity and hypergravity relative to 1g controls. Lenses formed in microgravity are larger and more developed than those regenerated in 1g controls; Microgravity alterations of lens regeneration can persist after spaceflight, and continue to affect repeated removal and regeneration of the lens after return to 1g; Microgravity increases the numbers of early stage regenerative proliferating BrdU-labeled cells in dorsal iris progenitors and in the lens regenerate. Regeneration under hypergravity conditions at 2g inhibits lens regeneration, and often causes retinal detachment. Molecular mechanisms regulating lens regeneration rate include FGF2 signaling, (a key pathway for eye tissue development and regeneration), and an expression of stress-related proteins - HSPs. In conclusion, regeneration of lens and other eye tissues in the newt is sensitive to, and regulated by the level of gravity mechanotransduction and developmental signaling pathways, with microgravity favoring stem cell progenitor proliferation, and gravity at 1g promoting terminal differentiation, while hypergravity at 2g often causes damage of delicate regenerating tissues.

  4. Reference commercial high-level waste glass and canister definition.

    SciTech Connect

    Slate, S.C.; Ross, W.A.; Partain, W.L.

    1981-09-01

    This report presents technical data and performance characteristics of a high-level waste glass and canister intended for use in the design of a complete waste encapsulation package suitable for disposal in a geologic repository. The borosilicate glass contained in the stainless steel canister represents the probable type of high-level waste product that will be produced in a commercial nuclear-fuel reprocessing plant. Development history is summarized for high-level liquid waste compositions, waste glass composition and characteristics, and canister design. The decay histories of the fission products and actinides (plus daughters) calculated by the ORIGEN-II code are presented.

  5. Evaluating Material Flammability in Microgravity and Martian Gravity Compared to the NASA Standard Normal Gravity Test

    NASA Technical Reports Server (NTRS)

    Oslon, Sandra. L.; Ferkul, Paul

    2012-01-01

    Drop tower tests are conducted at Martian gravity to determine the flammability of three materials compared to previous tests in other normal gravity and reduced gravity environments. The comparison is made with consideration of a modified NASA standard test protocol. Material flammability limits in the different gravity and flow environments are tabulated to determine the factor of safety associated with normal gravity flammability screening. Previous testing at microgravity and Lunar gravity indicated that some materials burned to lower oxygen concentrations in low gravity than in normal gravity, although the low g extinction limit criteria are not the same as 1g due to time constraints in drop testing. Similarly, the data presented in this paper for Martian gravity suggest that there is a gravity level below Earth s at which materials burn more readily than on Earth. If proven for more materials, this may indicate the need to include a factor of safety on 1g flammability limits.

  6. The ATLAS high level trigger region of interest builder.;

    SciTech Connect

    Blair, R.; Dawson, J.; Drake, G.; Haberichter, W.; Schlereth, J.; Zhang, J.; Ermoline, Y.; Pope, B.; Aboline, M.; High Energy Physics; Michigan State Univ.

    2008-04-01

    This article describes the design, testing and production of the ATLAS Region of Interest Builder (RoIB). This device acts as an interface between the Level 1 trigger and the high level trigger (HLT) farm for the ATLAS LHC detector. It distributes all of the Level 1 data for a subset of events to a small number of (16 or less) individual commodity processors. These processors in turn provide this information to the HLT. This allows the HLT to use the Level 1 information to narrow data requests to areas of the detector where Level 1 has identified interesting objects.

  7. Retrieving mesospheric winds and gravity waves using high resolution radar measurements of polar mesospheric summer echoes with MAARSY

    NASA Astrophysics Data System (ADS)

    Stober, G.; Sommer, S.; Schult, C.; Chau, J. L.; Latteck, R.

    2013-12-01

    The Middle Atmosphere Alomar Radar System (MAARSY) located at the northern Norwegian island of Andya (69.3 N, 16 E) observes polar mesosphere summer echoes (PMSE) on a regular basis. This backscatter turned out to be an ideal tracer of atmospheric dynamics and to investigate the wind field at the mesosphere/lower thermosphere (MLT) at high spatial and temporal scales. MAARSY is dedicated to explore the polar mesosphere at such high resolution and employs an active phased array antenna with the capability to steer the beam on a pulse-to-pulse basis, which permits to perform systematic scanning of PMSE and to investigate the horizontal structure of the backscatter. The radar also uses a 16 channel receiver system for interferometric applications e.g. mean angle of arrival analysis or coherent radar imaging. Here we present measurements using these features of MAARSY to study the wind field at the MLT applying sophisticated wind analysis algorithms such as velocity azimuth display or volume velocity processing to derive gravity wave parameters such as horizontal wave length, phase speed and propagation direction. Further, we compare the interferometrically corrected and uncorrected wind measurements to emphasize the importance to account for likely edge effects using PMSE as tracer of the dynamics. The observations indicate huge deviations from the nominal beam pointing direction at the upper and lower edges of the PMSE altering the wind analysis.

  8. Verifications of the high-resolution numerical model and polarization relations of atmospheric acoustic-gravity waves

    NASA Astrophysics Data System (ADS)

    Gavrilov, N. M.; Kshevetskii, S. P.; Koval, A. V.

    2015-06-01

    Comparisons of amplitudes of wave variations of atmospheric characteristics obtained using direct numerical simulation models with polarization relations given by conventional theories of linear acoustic-gravity waves (AGWs) could be helpful for testing these numerical models. In this study, we performed high-resolution numerical simulations of nonlinear AGW propagation at altitudes 0-500 km from a plane wave forcing at the Earth's surface and compared them with analytical polarization relations of linear AGW theory. After some transition time te (increasing with altitude) subsequent to triggering the wave source, the initial wave pulse disappears and the main spectral components of the wave source dominate. The numbers of numerically simulated and analytical pairs of AGW parameters, which are equal with confidence of 95 %, are largest at altitudes 30-60 km at t > te. At low and high altitudes and at t < te, numbers of equal pairs are smaller, because of the influence of the lower boundary conditions, strong dissipation and AGW transience making substantial inclinations from conditions, assumed in conventional theories of linear nondissipative stationary AGWs in the free atmosphere. Reasonable agreements between simulated and analytical wave parameters satisfying the scope of the limitations of the AGW theory prove the adequacy of the used wave numerical model. Significant differences between numerical and analytical AGW parameters reveal circumstances when analytical theories give substantial errors and numerical simulations of wave fields are required. In addition, direct numerical AGW simulations may be useful tools for testing simplified parameterizations of wave effects in the atmosphere.

  9. [Biology of size and gravity].

    PubMed

    Yamashita, Masamichi; Baba, Shoji A

    2004-03-01

    Gravity is a force that acts on mass. Biological effects of gravity and their magnitude depend on scale of mass and difference in density. One significant contribution of space biology is confirmation of direct action of gravity even at the cellular level. Since cell is the elementary unit of life, existence of primary effects of gravity on cells leads to establish the firm basis of gravitational biology. However, gravity is not limited to produce its biological effects on molecules and their reaction networks that compose living cells. Biological system has hierarchical structure with layers of organism, group, and ecological system, which emerge from the system one layer down. Influence of gravity is higher at larger mass. In addition to this, actions of gravity in each layer are caused by process and mechanism that is subjected and different in each layer of the hierarchy. Because of this feature, summing up gravitational action on cells does not explain gravity for biological system at upper layers. Gravity at ecological system or organismal level can not reduced to cellular mechanism. Size of cells and organisms is one of fundamental characters of them and a determinant in their design of form and function. Size closely relates to other physical quantities, such as mass, volume, and surface area. Gravity produces weight of mass. Organisms are required to equip components to support weight and to resist against force that arise at movement of body or a part of it. Volume and surface area associate with mass and heat transport process at body. Gravity dominates those processes by inducing natural convection around organisms. This review covers various elements and process, with which gravity make influence on living systems, chosen on the basis of biology of size. Cells and biochemical networks are under the control of organism to integrate a consolidated form. How cells adjust metabolic rate to meet to the size of the composed organism, whether is gravity responsible for this feature, are subject we discuss in this article. Three major topics in gravitational and space biology are; how living systems have been adapted to terrestrial gravity and evolved, how living systems respond to exotic gravitational environment, and whether living systems could respond and adapt to microgravity. Biology of size can contribute to find a way to answer these question, and answer why gravity is important in biology, at explaining why gravity has been a dominant factor through the evolutional history on the earth. PMID:15173628

  10. Time dependent corrections to absolute gravity determinations in the establishment of modern gravity control

    NASA Astrophysics Data System (ADS)

    Dykowski, Przemyslaw; Krynski, Jan

    2015-04-01

    The establishment of modern gravity control with the use of exclusively absolute method of gravity determination has significant advantages as compared to the one established mostly with relative gravity measurements (e.g. accuracy, time efficiency). The newly modernized gravity control in Poland consists of 28 fundamental stations (laboratory) and 168 base stations (PBOG14 - located in the field). Gravity at the fundamental stations was surveyed with the FG5-230 gravimeter of the Warsaw University of Technology, and at the base stations - with the A10-020 gravimeter of the Institute of Geodesy and Cartography, Warsaw. This work concerns absolute gravity determinations at the base stations. Although free of common relative measurement errors (e.g. instrumental drift) and effects of network adjustment, absolute gravity determinations for the establishment of gravity control require advanced corrections due to time dependent factors, i.e. tidal and ocean loading corrections, atmospheric corrections and hydrological corrections that were not taken into account when establishing the previous gravity control in Poland. Currently available services and software allow to determine high accuracy and high temporal resolution corrections for atmospheric (based on digital weather models, e.g. ECMWF) and hydrological (based on hydrological models, e.g. GLDAS/Noah) gravitational and loading effects. These corrections are mostly used for processing observations with Superconducting Gravimeters in the Global Geodynamics Project. For the area of Poland the atmospheric correction based on weather models can differ from standard atmospheric correction by even 2 Gal. The hydrological model shows the annual variability of 8 Gal. In addition the standard tidal correction may differ from the one obtained from the local tidal model (based on tidal observations). Such difference at Borowa Gora Observatory reaches the level of 1.5 Gal. Overall the sum of atmospheric and hydrological effects and tidal model uncertainty easily exceeds the Total Uncertainty of the A10-020 gravimeter which makes these effects vital for current and future absolute gravity determinations for the needs of the gravity control. This work presents the variability of the atmospheric, hydrological and tidal corrections based on selected models for the area of Poland, especially for the time period of the survey of base stations of the gravity control in Poland in 2012 and 2013. The discrepancies between simplified corrections and the advanced ones are presented showing the importance of the use of advanced corrections. Additionally a time series of 5 years of absolute gravity determinations with the A10-020 gravimeter on laboratory and field stations at Borowa Gora Observatory test network has been analyzed to access the observed variation of gravity with the use of advanced correction models. Also gravity measured in two epochs on a few PBOG14 stations were used to examine the determined gravity difference. The analysis of the A10-020 data includes metrological calibrations as well as traceability to the ICAG and ECAG campaigns.

  11. Crustal architecture of the Faroe-Shetland Margin: insights from a newly merged high resolution gravity and magnetic dataset

    NASA Astrophysics Data System (ADS)

    Rippington, Stephen; Mazur, Stan; Anderson, Chris

    2014-05-01

    The Faroe-Shetland region is geologically complex; it has undergone several phases of extension and rifting since the middle Palaeozoic (Ritchie et al., 2011; Coward et al., 2003), culminating in the Eocene with continental breakup between Northwest Europe and Greenland (Gernigon et al., 2012). Final breakup may have been facilitated by the presence of the Iceland Plume and was accompanied by the emplacement of voluminous basaltic rocks, attributed to the North Atlantic Igneous Province (White and McKenzie, 1989). It is difficult to image beneath the thick Paleogene basalts in the region using conventional seismic methods, because the high impedance contrast between the sediments and shallow basalts causes strong reflections. These mask deeper and weaker reflections and cause prominent inter-bed multiples (White et al., 1999). Consequently, determining the location and shape of basins and basement highs, and elucidating the timing and manner of their formation, remains a major cause of uncertainty in the appraisal of the hydrocarbon potential of the region. Gravity and magnetic data record variations in the density and susceptibility of the entire crust. Consequently, the thick basalt piles that are shallow in the section do not hinder the ability to detect deeper features. Instead, the principal challenge is distinguishing superposed bodies, with different densities and susceptibilities, from the combined gravity and magnetic anomalies. In this study, seismic data and horizons from the shallow section are used in combination with gravity and magnetic data to produce map view interpretations, and 2D and 3D models of the crust in the Faroe-Shetland region. These models help distinguish important variations in timing of rifting in different basins, and reveal the crustal architecture of the Faroe-Shetland Basin from the seabed to the Moho. We present a new structural and kinematic interpretation of the geology of the region, and propose an asymmetric simple shear model for the Faroe-Shetland segment of the UK Atlantic Margin. The authors would like to acknowledge the management at ARKeX and PGS for giving permission to present this work. Coward, M.., Dewey, J.F., Hempton, M., and Holroyd, J., 2003, Tectonic evolution, in Evans, D., Graham, C.G., Armour, A., and P, B. eds., Millenium Atlas: petroleum geology of the central and northern North Sea, Geological Society of London. Gernigon, L., Gaina, C., Olesen, O., Ball, P.J., Péron-Pinvidic, G., and Yamasaki, T., 2012, The Norway Basin revisited: From continental breakup to spreading ridge extinction: Marine and Petroleum Geology, v. 35, no. 1, p. 1-19. Ritchie, J.D., Ziska, H., Johnson, H., and Evans, D., 2011, Structure, in Ritchie, J.D., Ziska, H., Johnson, H., and Evans, D. eds., Geology of the Faroe-Shetland Basin and adjacent areas, British Geological Survey, Faroeses Earth and Energy Directorate, p. 9-70. White, R.S., Fruehn, J., Richardson, K.R., Cullen, E., Kirk, W., and Latkiewicz, C., 1999, Faeroes Large Aperture Research Experiment ( FLARE ): imaging through basalt, in Fleet, A.J. and Boldy, S.A.R. eds., Petroleum Geology of Northwest Europe and Global Perspectives: Proceedings of the 5th Conference, Geological Society of London, p. 1243-1252. White, R., and McKenzie, D., 1989, Magmatism at Rift Zones: The Generation of Volcanic Continental Margins: Journal of Geophysical Research, v. 94, no. B6, p. 7685-7729.

  12. Secondary arm coarsening and microsegregation in superalloy PWA-1480 single crystals: Effect of low gravity

    NASA Technical Reports Server (NTRS)

    Vijayakumar, M.; Tewari, S. N.; Lee, J. E.; Curreri, P. A.

    1990-01-01

    Single crystal specimens of nickel base superalloy PWA-1480 were directionally solidified on ground and during low gravity (20 sec) and high gravity (90 sec) parabolic maneuver of KC-135 aircraft. Thermal profiles were measured during solidification by two in-situ thermocouples positioned along the sample length. The samples were quenched during either high or low gravity cycles so as to freeze the structures of the mushy zone developing under different gravity levels. Microsegregation was measured by examining the solutal profiles on several transverse cross-sections across primary dendrites along their length in the quenched mushy zone. Effect of gravity level on secondary arm coarsening kinetics and microsegregation have been investigated. The results indicate that there is no appreciable difference in the microsegregation and coarsening kinetics behavior in the specimens grown under high or low gravity. This suggests that short duration changes in gravity/levels (0.02 to 1.7 g) do not influence convection in the interdendritic region. Examination of the role of natural convection, in the melt near the primary dendrite tips, on secondary arm spacings requires low gravity periods longer than presently available on KC-135. Secondary arm coarsening kinetics show a reasonable fit with the predictions from a simple analytical model proposed by Kirkwood for a binary alloy.

  13. Neptunium estimation in dissolver and high-level-waste solutions

    SciTech Connect

    Pathak, P.N.; Prabhu, D.R.; Kanekar, A.S.; Manchanda, V.K.

    2008-07-01

    This papers deals with the optimization of the experimental conditions for the estimation of {sup 237}Np in spent-fuel dissolver/high-level waste solutions using thenoyltrifluoroacetone as the extractant. (authors)

  14. Holism and High Level Wellness in the Treatment of Alcoholism.

    ERIC Educational Resources Information Center

    Bartha, Robert; Davis, Tom

    1982-01-01

    Discusses how a holistic and wellness philosophy is a viable alternative in the treatment of alcoholism. Describes five major dimensions of high-level wellness: nutritional awareness, physical fitness, stress management, environmental sensitivity, and self-responsibility. (RC)

  15. High Uric-Acid Levels, Lower Risk of Parkinson's?

    MedlinePLUS

    ... html High Uric-Acid Levels, Lower Risk of Parkinson's? Link found only in men, researchers say To ... their blood may be less likely to develop Parkinson's disease, a new study suggests. Researchers compared about ...

  16. Separation of Iron Phase and P-Bearing Slag Phase from Gaseous-Reduced, High-Phosphorous Oolitic Iron Ore at 1473 K (1200 C) by Super Gravity

    NASA Astrophysics Data System (ADS)

    Gao, Jintao; Zhong, Yiwei; Guo, Lei; Guo, Zhancheng

    2016-01-01

    In situ observation on the morphology evolution and phosphorous migration of gaseous-reduced, high-phosphorous oolitic iron ore during the melting process was carried out with a high-temperature confocal scanning laser microscope. The results showed that 1473 K (1200 C) was a critical temperature at which the gangue minerals started to form into the slag phase while the iron grains remained in a solid state; in addition, the phosphorus remained in the slag phase. Since the separation of iron grains and P-bearing slag was not achieved at the low temperature under the conventional conditions, separate experiments of the iron phase and the P-bearing slag phase from gaseous-reduced, high-phosphorous oolitic iron ore at 1473 K (1200 C) by super gravity were carried out in this study. Based on the iron-slag separation by super gravity, phosphorus was removed effectively from the iron phase at the temperature below the melting point of iron. Iron grains moved along the super-gravity direction, joined, and concentrated as the iron phase on the filter, whereas the slag phase containing apatite crystals broke through the barriers of the iron grains and went through the filter. Consequently, increasing the gravity coefficient was definitely beneficial for the separation of the P-bearing slag phase from the iron phase. With the gravity coefficient of G = 1200, the mass fractions of separated slag and iron phases were close to their respective theoretical values, and the mass fraction of MFe in the separated iron phase was up to 98.09 wt pct and that of P was decreased to 0.083 wt pct. The recovery of MFe in the iron phase and that of P in the slag phase were up to 99.19 and 95.83 pct, respectively.

  17. Field Trips as Cognitive Motivators for High Level Science Learning

    ERIC Educational Resources Information Center

    Hurley, Marlene M.

    2006-01-01

    Using a composite example of field trips from several years of traveling to Yellowstone with high school biology students, the author illustrates how to raise the cognitive level of science instruction and student learning through science field trips. The author examines what teachers can do to raise the level of both teaching and learning in all

  18. High-Level Waste System Process Interface Description

    SciTech Connect

    d'Entremont, P.D.

    1999-01-14

    The High-Level Waste System is a set of six different processes interconnected by pipelines. These processes function as one large treatment plant that receives, stores, and treats high-level wastes from various generators at SRS and converts them into forms suitable for final disposal. The three major forms are borosilicate glass, which will be eventually disposed of in a Federal Repository, Saltstone to be buried on site, and treated water effluent that is released to the environment.

  19. Gravity, Magnetism, and "Down": Non-Physics College Students' Conceptions of Gravity

    ERIC Educational Resources Information Center

    Asghar, Anila; Libarkin, Julie C.

    2010-01-01

    This study investigates how students enrolled in entry-level geology, most of whom would graduate from college without university-level physics courses, thought about and applied the concept of gravity while solving problems concerning gravity. The repercussions of students' gravity concepts are then considered in the context of non-physics…

  20. Highly efficient and flexible electrospun carbon-silica nanofibrous membrane for ultrafast gravity-driven oil-water separation.

    PubMed

    Tai, Ming Hang; Gao, Peng; Tan, Benny Yong Liang; Sun, Darren D; Leckie, James O

    2014-06-25

    A novel free-standing and flexible electrospun carbon-silica composite nanofibrous membrane is newly introduced. The characterization results suggest that the electrospun composite nanofibers are constructed by carbon chains interpenetrated through a linear network of 3-dimensional SiO2. Thermogravimetric analysis indicates that the presence of insulating silica further improve the thermal resistance of the membrane. Additionally, the mechanical strength test shows that the membrane's toughness and flexibility can be enhanced if the concentration of SiO2 is maintained below 2.7 wt %. Thermal and chemical stability test show that the membrane's wettability properties can be sustained at an elevated temperature up to 300 C and no discernible change in wettability was observed under highly acidic and basic conditions. After surface-coating with silicone oil for 30 mins, the composite membrane exhibits ultra-hydrophobic and superoleophilic properties with water and oil contact angles being 144.2 1.2 and 0, respectively. The enhanced flexibility and selective wetting property enables the membrane to serve as an effective substrate for separating free oil from water. Lab-scale oil-water separation test indicates that the membrane possesses excellent oil-water separation efficiency. In addition, its inherent property of high porosity allows oil-water separation to be performed in a gravity-driven process with high-flux. We anticipate that this study will open up a new avenue for fabrication of free-standing carbonaceous composite membrane with tunable flexibility for energy efficient and high-throughput production of clean water. PMID:24867399

  1. Tongji-GRACE01: A GRACE-only static gravity field model recovered from GRACE Level-1B data using modified short arc approach

    NASA Astrophysics Data System (ADS)

    Chen, Qiujie; Shen, Yunzhong; Zhang, Xingfu; Chen, Wu; Hsu, Houze

    2015-09-01

    The modified short arc approach, where the position vector in force model are regarded as pseudo observation, is implemented in the SAtellite Gravimetry Analysis Software (SAGAS) developed by Tongji university. Based on the SAGAS platform, a static gravity field model (namely Tongji-GRACE01) complete to degree and order 160 is computed from 49 months of real GRACE Level-1B data spanning the period 2003-2007 (including the observations of K-band range-rate, reduced dynamic orbits, non-conservative accelerations and altitudes). The Tongji-GRACE01 model is compared with the recent GRACE-only models (such as GGM05S, AIUB-GRACE03S, ITG-GRACE03, ITG-GRACE2010S, and ITSG-GRACE2014S) and validated with GPS-leveling data sets in different countries. The results show that the Tongji-GRACE01 model has a considered quality as GGM05S, AIUB-GRACE03S and ITG-GRACE03. The Tongji-GRACE01 model is available at the International Centre for Global Earth Models (ICGEM) web page (http://icgem.gfz-potsdam.de/ICGEM/).

  2. Exploring Gravity Wave Predictability and Dynamics in Deepwave

    NASA Astrophysics Data System (ADS)

    Doyle, J. D.; Fritts, D. C.; Smith, R. B.; Eckermann, S. D.; Taylor, M. J.; Drnbrack, A.; Uddstrom, M.; Reynolds, C. A.; Reinecke, A.; Jiang, Q.

    2014-12-01

    The DEEP propagating gravity WAVE program (DEEPWAVE) is a comprehensive, airborne and ground-based measurement and modeling program centered on New Zealand and focused on providing a new understanding of gravity wave dynamics and impacts from the troposphere through the mesosphere and lower thermosphere (MLT). This program employed the NSF/NCAR GV (NGV) research aircraft from a base in New Zealand in a 6-week field measurement campaign in June-July 2014. During the field phase, the NGV was equipped with new lidar and airglow instruments, as well as dropwindsondes and a full suite of flight level instruments including the microwave temperature profiler (MTP), providing temperatures and vertical winds spanning altitudes from immediately above the NGV flight altitude (~13 km) to ~100 km. The region near New Zealand was chosen since all the relevant GW sources (e.g., mountains, cyclones, jet streams) occur strongly here, and upper-level winds in austral winter permit gravity waves to propagate to very high altitudes. The COAMPS adjoint modeling system provided forecast sensitivity in real time during the six-week DEEPWAVE field phase. Five missions were conducted using the NGV to observe regions of high forecast sensitivity, as diagnosed using the COAMPS adjoint model. In this presentation, we provide a summary of the sensitivity characteristics and explore the implications for predictability of low-level winds crucial for gravity wave launching, as well as predictability of gravity wave characteristics in the stratosphere. In general, the sensitive regions were characterized by localized strong dynamics, often involving intense baroclinic systems with deep convection. The results of the adjoint modeling system suggest that gravity wave launching and the characteristics of the gravity waves can be linked to these sensitive regions near frontal zones within baroclinic systems. The predictability links between the tropospheric fronts, cyclones, jet regions, and gravity waves that vertically propagate upward through the stratosphere will be addressed further in the presentation.

  3. Gravity and Biology

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily R.

    1996-01-01

    Gravity has been the most constant environmental factor throughout the evolution of biological species on Earth. Organisms are rarely exposed to other gravity levels, either increased or decreased, for prolonged periods. Thus, evolution in a constant 1G field has historically prevented us from appreciating the potential biological consequences of a multi-G universe. To answer the question 'Can terrestrial life be sustained and thrive beyond our planet?' we need to understand the importance of gravity on living systems, and we need to develop a multi-G, rather than a 1G, mentality. The science of gravitational biology took a giant step with the advent of the space program, which provided the first opportunity to examine living organisms in gravity environments lower than could be sustained on Earth. Previously, virtually nothing was known about the effects of extremely low gravity on living organisms, and most of the initial expectations were proven wrong. All species that have flown in space survive in microgravity, although no higher organism has ever completed a life cycle in space. It has been found, however, that many systems change, transiently or permanently, as a result of prolonged exposure to microgravity.

  4. Global gene expression analysis of Saccharomyces cerevisiae grown under redox potential-controlled very-high-gravity conditions.

    PubMed

    Liu, Chen-Guang; Lin, Yen-Han; Bai, Feng-Wu

    2013-11-01

    Redox potential (ORP) plays a pivotal role in yeast viability and ethanol production during very-high-gravity (VHG) ethanol fermentation. In order to identify the correlation between redox potential profiles and gene expression patterns, global gene expression of Saccharomyces cerevisiae was investigated. Results indicated that significant changes in gene expression occurred at the periods of 0 - 6 h and 30 - 36 h, respectively. Changes noted in the period of 0 - 6 h were mainly related to carbohydrate metabolism. In contrast, gene expression variation at 30 - 36 h could be attributed primarily to stress response. Although CDC19 was down-regulated, expression of PYK2, PDC6 and ADH2 correlated inversely with ORP. Meanwhile, expression of GPD1 decreased due to the depletion of dissolved oxygen in the fermentation broth, but expression of GPD2 correlated with ORP. Transcription of genes encoding heat shock proteins was characterized by uphill, downhill, valley and plateau expression profiles, accordingly to specific function in stress response. These results highlight the role of ORP in modulating yeast physiology and metabolism under VHG conditions. PMID:23625881

  5. Toward the AdS/CFT gravity dual for high energy collisions. I. Falling into the AdS space

    SciTech Connect

    Lin Shu; Shuryak, Edward

    2008-04-15

    In the context of the AdS/CFT correspondence we discuss the gravity dual of a high energy collision in a strongly coupled N=4 SYM gauge theory. We suggest a setting in which two colliding objects are made of nondynamical heavy quarks and antiquarks, which allows one to treat the process in classical string approximation. Collision 'debris' consist of closed as well as open strings. If the latter have ends on two outgoing charges, they are being 'stretched' along the collision axes. We discuss motion in AdS of some simple objects first--massless and massive particles--and then focus on open strings. We study the latter in considerable detail, concluding that they rapidly become 'rectangular' in proper time-spatial rapidity {tau}-y coordinates with well separated fragmentation part and a near-free-falling rapidity-independent central part. Assuming that in the collisions of 'walls' of charges multiple stretching strings are created, we also consider the motion of a 3D stretching membrane. We then argue that a complete solution can be approximated by two different vacuum solutions of Einstein equations, with matter membrane separating them. We identify one of these solutions with a Janik-Peschanski stretching black hole solution, and show that all objects approach its (retreating) horizon in a universal manner.

  6. On the impact of airborne gravity data to fused gravity field models

    NASA Astrophysics Data System (ADS)

    Bolkas, Dimitrios; Fotopoulos, Georgia; Braun, Alexander

    2016-03-01

    In gravity field modeling, fused models that utilize satellite, airborne and terrestrial gravity observations are often employed to deal with erroneous terrestrially derived gravity datasets. These terrestrial datasets may suffer from long-wavelength systematic errors and inhomogeneous data coverage, which are not prevalent in airborne and satellite datasets. Airborne gravity acquisition plays an essential role in gravity field modeling, providing valuable information of the Earth's gravity field at medium and short wavelengths. Thus, assessing the impact of airborne gravity data to fused gravity field models is important for identifying problematic regions. Six study regions that represent different gravity field variability and terrestrial data point-density characteristics are investigated to quantify the impact of airborne gravity data to fused gravity field models. The numerical assessments of these representative regions resulted in predictions of airborne gravity impact for individual states and provinces in the USA and Canada, respectively. Prediction results indicate that, depending on the terrestrial data point-density and gravity field variability, the expected impact of airborne gravity can reach up to 3mGal (in terms of standard deviation) in Canada and Alaska (over areas of 1° × 1°). However, in the mainland US region, small changes are expected (0.2-0.4 mGal over areas of 1° × 1°) due to the availability of high spatial resolution terrestrial data. These results can serve as a guideline for setting airborne gravity data acquisition priorities and for improving future planning of airborne gravity surveys.

  7. An overview of very high level software design methods

    NASA Technical Reports Server (NTRS)

    Asdjodi, Maryam; Hooper, James W.

    1988-01-01

    Very High Level design methods emphasize automatic transfer of requirements to formal design specifications, and/or may concentrate on automatic transformation of formal design specifications that include some semantic information of the system into machine executable form. Very high level design methods range from general domain independent methods to approaches implementable for specific applications or domains. Applying AI techniques, abstract programming methods, domain heuristics, software engineering tools, library-based programming and other methods different approaches for higher level software design are being developed. Though one finds that a given approach does not always fall exactly in any specific class, this paper provides a classification for very high level design methods including examples for each class. These methods are analyzed and compared based on their basic approaches, strengths and feasibility for future expansion toward automatic development of software systems.

  8. Geographic distribution of zonal wind and UV albedo at cloud top level from VMC camera on Venus Express: Influence of Venus topography through stationary gravity waves vertical propagation.

    NASA Astrophysics Data System (ADS)

    Bertaux, Jean-Loup; Khatunstsev, Igor; Hauchecorne, Alain; Markiewicz, Wojciech; Marcq, Emmanuel; Lebonnois, Sébastien; Patsaeva, Marina; Turin, Alexander

    2015-04-01

    UV images (at 365 nm) of Venus cloud top collected with VMC camera on board Venus Express allowed to derive a large number of wind measurements at altitude 67±2 km from tracking of cloud features in the period 2006-2012. Both manual (45,600) and digital (391,600) individual wind measurements over 127 orbits were analyzed showing various patterns with latitude and local time. A new longitude-latitude geographic map of the zonal wind shows a conspicuous region of strongly decreased zonal wind, a remarkable feature that was unknown up to now. While the average zonal wind near equator (from 5°S to 15°s) is -100.9 m/s in the longitude range 200-330°, it reaches -83.4 m/s in the range 60-100°, a difference of 17.5 m/s. When compared to the altimetry map of Venus, it is found that the zonal wind pattern is well correlated with the underlying relief in the region of Aphrodite Terra, with a downstream shift of about 30° (˜3,200 km). We interpret this pattern as the result of stationary gravity waves produced at ground level by the up lift of air when the horizontal wind encounters a mountain slope. These waves can propagate up to cloud top level, break there and transfer their momentum to the zonal flow. A similar phenomenon is known to operate on Earth with an influence on mesospheric winds. The LMD-GCM for Venus was run with or without topography, with and without a parameterization of gravity waves and does not display such an observed change of velocity near equator. The cloud albedo map at 365 nm varies also in longitude and latitude. We speculate that it might be the result of increased vertical mixing associated to wave breaking, and decreased abundance of the UV absorber which makes the contrast in images. The impact of these new findings on current super rotation theories remains to be assessed. This work was triggered by the presence of a conspicuous peak at 117 days in a time series of wind measurements. This is the length of the solar day as seen at the ground of Venus. Since VMC measurements are done preferably in a local time window centred on the sub-solar point, any parameter having a geographic longitude dependence will show a peak at 117 days.

  9. GRAIL Gravity Field Determination Using the Celestial Mechanics Approach

    NASA Astrophysics Data System (ADS)

    Arnold, Daniel; Jggi, Adrian; Bertone, Stefano; Beutler, Gerhard; Meyer, Ulrich; Mervart, Leos; Bock, Heike

    2014-05-01

    To determine the gravity field of the Moon, the NASA mission GRAIL (Gravity Recovery and Interior Laboratory) inherits its concept from the GRACE (Gravity Recovery and Climate Experiment) mission. The use of inter-satellite Ka-band range-rate (KBRR) observations enables data acquisition even when the spacecraft are not tracked from the Earth. The data allows for a highly accurate estimation of the lunar gravity field on both sides of the Moon, which is crucial to improve the understanding of its internal structure and thermal evolution. In this presentation we discuss GRAIL-based lunar gravity fields generated with the Celestial Mechanics Approach. KBRR observations and position data (GNI1B products) are used to solve for the lunar gravity field parameters in a generalized orbit determination problem. Apart from normalized spherical harmonic coefficients up to degrees n ? 200, also arc- and satellite-specific parameters, like initial state vectors and pseudo-stochastic pulses, are set up as common parameters for all measurement types. The latter shall compensate for imperfect models of non-gravitational accelerations, e.g., caused by solar radiation pressure. In addition, especially for the data of the primary mission phase, it is essential to estimate time bias parameters for the KBRR observations. We compare our results from the nominal and from the extended mission phase with the official Level 2 gravity field models first released in October 2013. Our results demonstrate that the lunar gravity field can be recovered with a high quality by adapting the Celestial Mechanics Approach, even when using pre-GRAIL or pre-SELENE gravity field models as a priori fields and when replacing sophisticated models of non-gravitational accelerations by appropriately spaced and constrained pseudo-stochastic pulses.

  10. Effect of tapioca starch and amyloglucosidase concentration on very high gravity simultaneous saccharification and fermentation (VHG-SSF) of bioethanol

    NASA Astrophysics Data System (ADS)

    Sugih, A. K.; Santoso, I. V.; Kristijarti, A. P.

    2015-12-01

    Tapioca starch is isolated from the root of cassava plant (Manihot esculenta). It is produced in a large quantity in Indonesia and other south east Asian countries. Tapioca starch has been commonly used as a feedstock for food as well as non-food industries. Due to its high carbohydrate content, tapioca starch has the potentiality to be used as a raw material for bioethanol production. In this research, a novel approach (Very High Gravity Simultaneous Sacharification and Fermentation/ VHG-SSF) to synthesise highly concentrated ethanol from tapioca starch was investigated. Tapioca starch suspension was first gelatinised for two hours at 90°C and hydrolised at the same temperature for another two hours using commercial α- amylase (Liquozyme Supra, 0.16%-v/ w starch). The pretreated suspension was sterilised and mixed with nitrogenous supplement. In order to start the fermentation, Saccharomyces cereviseae NRRL Y-132 inoculum (10%-v/v; 107 cells/ ml) and commercial amyloglucosidase (Dextrozyme GA, 35-105 AGU/ g starch) were added to the mixture. The initial total carbohydrate, yeast extract, and peptone concentrations of the fermentation broths were 30-40 %-w/v, 1%-w/v, and 2%-w/v, respectively. VHG-SSF was allowed to proceed for 6 days at 30°C with rotary shaker speed of 100 rpm. The concentration of glucose and ethanol during fermentation was monitored using HPLC. The experimental result shows that tapioca starch has been successfully converted to ethanol with a final concentration of 10.12-16.14 %-w/v, which is corresponding to yield of 34.68-56.83 %-w ethanol/ w-converted sugar. The result suggests that VHG-SSF is a prospective method to synthesise bioethanol from tapioca starch.

  11. A Testing Instrument for High School Arabic, Level III.

    ERIC Educational Resources Information Center

    Wolowelsky, Joel B.

    The Arabic language examination was designed for Jewish immigrants from Syria wishing to satisfy New York State language requirements for high school graduation by indicating their proficiency in Arabic. The test is essentially a translation of a state test of Hebrew, and is intended to test Arabic at the third-year high school level. The

  12. Predicting gravity and sediment thickness in Afghanistan

    NASA Astrophysics Data System (ADS)

    Jung, W.; Brozena, J.; Peters, M.

    2013-02-01

    The US Naval Research Laboratory conducted comprehensive high-altitude (7 km above mean sea level) aero-geophysical surveys over Afghanistan in 2006 (Rampant Lion I). The surveys were done in collaboration with the US Geological Survey and upon the request of Islamic Republic of Afghanistan Ministry of Mines. In this study, we show that a best fitting admittance between topography and airborne gravity in western Afghanistan can be used to predict airborne gravity for the no-data area of eastern Afghanistan where the mountains are too high to conduct airborne surveys, due to the threat of ground fire. The differences between the airborne and the predicted gravity along a tie-track through the no-data area were found to be within 12 mGal range with rms difference 7.3 mGal, while those between the predicted gravity from a simple Airy model (with compensation depth of 32 km and crustal density of 2.67 g cm-3) and the airborne gravity were within 22 mGal range with rms difference 10.3 mGal. A combined airborne free-air anomaly has been constructed by merging the predicted gravity with the airborne data. We also demonstrate that sediment thickness can be estimated for basin areas where surface topography and airborne free-air anomaly profiles do not show a correlation presumably because of thick sediments. In order to estimate sediment thickness, we first determine a simple linear relationship from a scatter plot of the airborne gravity points and the interpolated Shuttle Radar Topography Mission (SRTM) topography along the Rampant Lion I tracks, and computed corresponding quasi-topography tracks by multiplying the linear relationship with the airborne free-air anomalies. We then take the differences between the SRTM and quasi-topography as a first-order estimate of sediment thickness. A global gravity model (GOCO02S), upward continued to the same altitude (7 km above mean sea level) as the data collection, was compared with the low-pass filtered (with cutoff wavelength 132 km which is approximately equivalent to the reported safe degree and order 250 of GOCO02S at 34 N) combined airborne free-air anomalies. The rms difference between the two data sets was 12.4 mGal. The observed admittance in the western Afghanistan mountains appears to be best fit to a theoretical elastic plate compensation model (with an effective elastic thickness of 5 km and crustal thickness of 22 km) where the ratio between surface load and subsurface load is equal.

  13. The effects of high presentation levels on consonant feature transmission

    NASA Astrophysics Data System (ADS)

    Hornsby, Benjamin W. Y.; Trine, Timothy D.; Ohde, Ralph N.

    2005-09-01

    The effect of high speech presentation levels on consonant recognition and feature transmission was assessed in eight participants with normal hearing. Consonant recognition in noise (0 dB signal-to-noise ratio) was measured at five overall speech levels ranging from 65 to 100 dB SPL. Consistent with the work of others, overall percent correct performance decreased as the presentation level of speech increased [e.g., G. A. Studebaker, R. L. Sherbecoe, D. M. McDaniel, and C. A. Gwaltney, J. Acoust. Soc. Am. 105(4), 2431-2444 (1999)]. Confusion matrices were analyzed in terms of relative percent information transmitted at each speech presentation level, as a function of feature. Six feature sets (voicing, place, nasality, duration, frication, and sonorance) were analyzed. Results showed the feature duration (long consonant duration fricatives) to be most affected by increases in level, while the voicing feature was relatively unaffected by increases in level. In addition, alveolar consonants were substantially affected by level, while palatal consonants were not. While the underlying mechanisms responsible for decreases in performance with level increases are unclear, an analysis of common error patterns at high levels suggests that saturation of the neural response and/or a loss of neural synchrony may play a role.

  14. High Power MPD Nuclear Electric Propulsion (NEP) for Artificial Gravity HOPE Missions to Callisto

    NASA Astrophysics Data System (ADS)

    McGuire, Melissa L.; Borowski, Stanley K.; Mason, Lee M.; Gilland, James

    2003-01-01

    The following paper documents the results of a one-year multi-center NASA study on the prospect of sending humans to Jupiter's moon, Callisto, using an all Nuclear Electric Propulsion (NEP) space transportation system architecture with magnetoplasmadynamic (MPD) thrusters. The fission reactor system utilizes high temperature uranium dioxide (UO2) in tungsten (W) metal matrix ``cermet'' fuel and electricity is generated using advanced dynamic Brayton power conversion technology. The mission timeframe assumes on-going human Moon and Mars missions and existing space infrastructure to support launch of cargo and crewed spacecraft to Jupiter in 2041 and 2045, respectively.

  15. High Power MPD Nuclear Electric Propulsion (NEP) for Artificial Gravity HOPE Missions to Callisto

    NASA Technical Reports Server (NTRS)

    McGuire, Melissa L.; Borowski, Stanley K.; Mason, Lee M.; Gilland, James

    2003-01-01

    This documents the results of a one-year multi-center NASA study on the prospect of sending humans to Jupiter's moon, Callisto, using an all Nuclear Electric Propulsion (NEP) space transportation system architecture with magnetoplasmadynamic (MPD) thrusters. The fission reactor system utilizes high temperature uranium dioxide (UO2) in tungsten (W) metal matrix cermet fuel and electricity is generated using advanced dynamic Brayton power conversion technology. The mission timeframe assumes on-going human Moon and Mars missions and existing space infrastructure to support launch of cargo and crewed spacecraft to Jupiter in 2041 and 2045, respectively.

  16. Simulating Gravity

    ERIC Educational Resources Information Center

    Pipinos, Savas

    2010-01-01

    This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity…

  17. Simulating Gravity

    ERIC Educational Resources Information Center

    Pipinos, Savas

    2010-01-01

    This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity

  18. Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    2009-11-01

    The continuing search for quantum gravity and never ending attempts to unify gravity with other forces of nature represent tremendous waste of public and private funds directing students' energy towards non-creative manipulative work instead of learning from the scientific creativity in Einstein's 1919 paper that unifies gravity with nuclear force. It reflects Einstein's 1919 jump beyond his own 1915 theory of gravity, including that of Newton as implicitly demanded by Newton in 1686. Einstein corrected and retracted his 1917 introduction of cosmological constant in 1919. Dislike of the fact that Einstein did not use quantum mechanics to prove his point has no real value now, because we will use key ingredients (Planck scale and probabilistic aspect) of quantum mechanics and show that they reach the same conclusion. Newton explained the solar system known after Kepler. Likewise, our quantum mechanical approach explains the strong coupling as well the solar system and shows new horizons, otherwise unexplained. Explanation of unexplained observations need no prediction per Hawking, and obviously otherwise.

  19. Effect of water immersion on cardiopulmonary physiology at high gravity (+Gz)

    NASA Technical Reports Server (NTRS)

    Arieli, R.; Boutellier, U.; Farhi, L. E.

    1986-01-01

    The cardiopulmonary responses of eight male subject between 21-31 years exposed to 1, 2, and 3 Gz during immersion at 35 + or - 0.5 C to heart level and during control dry rides are studied. Ventilation, O2 consumption, the end-tidal pressure of CO2, heart frequency, cardiac output, functional residual capacity, and the arterial pressure of CO2 were measured. It is observed that as Gz increases ventilation, heart frequency, and O2 consumption increase, and the end-tidal and arterial pressures of CO2 decrease during dry rides, but are not altered during immersion. It is detected that the functional residual capacity is lower during immersion and decreases in both the dry and immersed state as Gz increases, and cardiac output decreases as Gz increases in dry rides. It is noted that changes produced by acceleration in a Gz direction are due to the effect on the systemic circulation rather than to the effect on the lungs.

  20. Proof of concept and performance optimization of high gravity batch type centrifuge for dewatering fine coal

    SciTech Connect

    Smith, L.B.; Durney, T.E. Jr.

    1991-01-28

    The objectives of this project is to generate and record a data base with the prototype centrifuge and to use the data base to determine the appropriateness of the system for coal processing and to determine how the more vital systems can be balanced so that the centrifuge can achieve optimum performance. Task 2 included the upgrading and testing of both the hardware and software of the data logging system. It also included improving and testing the data transducers as well as those support hardware systems which were preventing the logging of the primary data in real time. The first sub-task in Task 3, consists of feasibility tests of the technology. In particular it is designed to demonstrate the ability of the non-blinding filter system to operate successfully over extended periods of time. The second subtask in Task 3, demonstrates the ability of the system to dry a variety of coals from various coal fields to satisfactory moisture levels. Task 3 has been completed. Task 4 is designed to optimize the operation and the interactions of the six most important systems in the new centrifugal dryers. The work plan schedule called for this task to begin at the completion of Task 3. However, during the testing in Tasks 2 and 3, it became evident that it would be necessary to perform some of the Task 4 optimization ahead of schedule. The earlier test work had uncovered serious problems with some of the systems scheduled to be optimized during Task 4, and so it was deemed to be appropriate to move ahead and address the problems earlier to enhance the value of Task 3. Results from the completed tasks as well as preliminary results from Task 4 are presented. 8 figs.

  1. Venus Gravity Handbook

    NASA Technical Reports Server (NTRS)

    Konopliv, Alexander S.; Sjogren, William L.

    1996-01-01

    This report documents the Venus gravity methods and results to date (model MGNP90LSAAP). It is called a handbook in that it contains many useful plots (such as geometry and orbit behavior) that are useful in evaluating the tracking data. We discuss the models that are used in processing the Doppler data and the estimation method for determining the gravity field. With Pioneer Venus Orbiter and Magellan tracking data, the Venus gravity field was determined complete to degree and order 90 with the use of the JPL Cray T3D Supercomputer. The gravity field shows unprecedented high correlation with topography and resolution of features to the 2OOkm resolution. In the procedure for solving the gravity field, other information is gained as well, and, for example, we discuss results for the Venus ephemeris, Love number, pole orientation of Venus, and atmospheric densities. Of significance is the Love number solution which indicates a liquid core for Venus. The ephemeris of Venus is determined to an accuracy of 0.02 mm/s (tens of meters in position), and the rotation period to 243.0194 +/- 0.0002 days.

  2. Attenuation of high-level acoustic impulses by earplugs

    NASA Astrophysics Data System (ADS)

    Zera, Jan; Mlynski, Rafal

    2001-05-01

    Attenuation of acoustic impulses by various models of foam, premolded, formable and semi-insert earplugs was measured. The impulses were generated by a loudspeaker system in the 115-130 range of levels, and by a blast of air expanding from a cylinder in the 150-170 level range. Transmission loss method was used to determine the difference between the peak level under the earplug and outside the earplug. The earplugs were inserted into in-house designed cylindrical or conical couplers attached to an artificial test fixture. The measurements showed that attenuation of high-level impulses depends on the type of coupler and the depth of earplug insertion. Attenuation measured using a conical coupler was consistently about 5 dB lower than for cylindrical coupler. Decreasing the depth of earplug insertion from 75% to 50% was especially critical at high level impulses and lowered attenuation by about 6 dB. For various models of foam and premolded earplugs, attenuation of high-level impulses varies by more than 20 dB. Particularly high attenuation was obtained for formable earplug made of modified wax. [Work supported by the State Committee for Scientific Research Grant No. III-7.03, III-6.07.

  3. Sensorimotor aspects of high-speed artificial gravity: II. The effect of head position on illusory self motion

    NASA Technical Reports Server (NTRS)

    Mast, F. W.; Newby, N. J.; Young, L. R.

    2002-01-01

    The effects of cross-coupled stimuli on the semicircular canals are shown to be influenced by the position of the subject's head with respect to gravity and the axis of rotation, but not by the subject's head position relative to the trunk. Seventeen healthy subjects made head yaw movements out of the horizontal plane while lying on a horizontal platform (MIT short radius centrifuge) rotating at 23 rpm about an earth-vertical axis. The subjects reported the magnitude and duration of the illusory pitch or roll sensations elicited by the cross-coupled rotational stimuli acting on the semicircular canals. The results suggest an influence of head position relative to gravity. The magnitude estimation is higher and the sensation decays more slowly when the head's final position is toward nose-up (gravity in the subject's head x-z-plane) compared to when the head is turned toward the side (gravity in the subject's head y-z-plane). The results are discussed with respect to artificial gravity in space and the possible role of pre-adaptation to cross-coupled angular accelerations on earth.

  4. Identification of candidate genes for yeast engineering to improve bioethanol production in very high gravity and lignocellulosic biomass industrial fermentations

    PubMed Central

    2011-01-01

    Background The optimization of industrial bioethanol production will depend on the rational design and manipulation of industrial strains to improve their robustness against the many stress factors affecting their performance during very high gravity (VHG) or lignocellulosic fermentations. In this study, a set of Saccharomyces cerevisiae genes found, through genome-wide screenings, to confer resistance to the simultaneous presence of different relevant stresses were identified as required for maximal fermentation performance under industrial conditions. Results Chemogenomics data were used to identify eight genes whose expression confers simultaneous resistance to high concentrations of glucose, acetic acid and ethanol, chemical stresses relevant for VHG fermentations; and eleven genes conferring simultaneous resistance to stresses relevant during lignocellulosic fermentations. These eleven genes were identified based on two different sets: one with five genes granting simultaneous resistance to ethanol, acetic acid and furfural, and the other with six genes providing simultaneous resistance to ethanol, acetic acid and vanillin. The expression of Bud31 and Hpr1 was found to lead to the increase of both ethanol yield and fermentation rate, while Pho85, Vrp1 and Ygl024w expression is required for maximal ethanol production in VHG fermentations. Five genes, Erg2, Prs3, Rav1, Rpb4 and Vma8, were found to contribute to the maintenance of cell viability in wheat straw hydrolysate and/or the maximal fermentation rate of this substrate. Conclusions The identified genes stand as preferential targets for genetic engineering manipulation in order to generate more robust industrial strains, able to cope with the most significant fermentation stresses and, thus, to increase ethanol production rate and final ethanol titers. PMID:22152034

  5. High dispersion spectroscopy of solar-type superflare stars. I. Temperature, surface gravity, metallicity, and vsin i

    NASA Astrophysics Data System (ADS)

    Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Nogami, Daisaku; Shibata, Kazunari

    2015-06-01

    We conducted high-dispersion spectroscopic observations of 50 superflare stars with Subaru High Dispersion Spectrograph (HDS), and measured the stellar parameters of them. These 50 targets were selected from the solar-type (G-type main sequence) superflare stars that we had discovered from the Kepler photometric data. As a result of these spectroscopic observations, we found that more than half (34) of our 50 targets have no evidence of binary systems. We then estimated the effective temperature (Teff), surface gravity (log g), metallicity ([Fe/H]), and projected rotational velocity (vsin i) of these 34 superflare stars on the basis of our spectroscopic data. The accuracy of our estimations is higher than that of the Kepler Input Catalog (KIC) values, and the differences between our values and KIC values [(ΔTeff)rms ˜ 219 K, (Δlog g)rms ˜ 0.37 dex, and (Δ[Fe/H])rms ˜ 0.46 dex] are comparable to the large uncertainties and systematic differences of KIC values reported by the previous researchers. We confirmed that the estimated Teff and log g values of the 34 superflare stars are roughly in the range of solar-type stars. In particular, these parameters and the brightness variation period (P0) of nine of the stars are in the range of "Sun-like" stars (5600 ≤ Teff ≤ 6000 K, log g ≥ 4.0, and P0 > 10 d). Five of the 34 target stars are fast rotators (vsin i ≥ 10 km s-1), while 22 stars have relatively low vsin i values (vsin i < 5 km s-1). These results suggest that stars that have spectroscopic properties similar to the Sun can have superflares, and this supports the hypothesis that the Sun might cause a superflare.

  6. Sensorimotor aspects of high-speed artificial gravity: I. Sensory conflict in vestibular adaptation

    NASA Technical Reports Server (NTRS)

    Brown, Erika L.; Hecht, Heiko; Young, Laurence R.

    2002-01-01

    Short-radius centrifugation offers a promising and affordable countermeasure to the adverse effects of prolonged weightlessness. However, head movements made in a fast rotating environment elicit Coriolis effects, which seriously compromise sensory and motor processes. We found that participants can adapt to these Coriolis effects when exposed intermittently to high rotation rates and, at the same time, can maintain their perceptual-motor coordination in stationary environments. In this paper, we explore the role of inter-sensory conflict in this adaptation process. Different measures (vertical nystagmus, illusory body tilt, motion sickness) react differently to visual-vestibular conflict and adapt differently. In particular, proprioceptive-vestibular conflict sufficed to adapt subjective parameters and the time constant of nystagmus decay, while retinal slip was required for VOR gain adaptation. A simple correlation between the strength of intersensory conflict and the efficacy of adaptation fails to explain the data. Implications of these findings, which differ from existing data for low rotation rates, are discussed.

  7. First test of high frequency Gravity Waves from inflation using Advanced LIGO

    SciTech Connect

    Lopez, Alejandro; Freese, Katherine E-mail: ktfreese@umich.edu

    2015-01-01

    Inflation models ending in a first order phase transition produce gravitational waves (GW) via bubble collisions of the true vacuum phase. We demonstrate that these bubble collisions can leave an observable signature in Advanced LIGO, an upcoming ground-based GW experiment. These GW are dependent on two parameters of the inflationary model: ε represents the energy difference between the false vacuum and the true vacuum of the inflaton potential, and χ measures how fast the phase transition ends (χ ∼ the number of e-folds during the actual phase transition). Advanced LIGO will be able to test the validity of single-phase transition models within the parameter space 10{sup 7} GeV∼< ε{sup 1/4} ∼< 10{sup 10} GeV and 0.19 ∼< χ ∼< 1. If inflation occurred through a first order phase transition, then Advanced LIGO could be the first to discover high frequency GW from inflation.

  8. Asymptotically Safe Lorentzian Gravity

    SciTech Connect

    Manrique, Elisa; Rechenberger, Stefan; Saueressig, Frank

    2011-06-24

    The gravitational asymptotic safety program strives for a consistent and predictive quantum theory of gravity based on a nontrivial ultraviolet fixed point of the renormalization group (RG) flow. We investigate this scenario by employing a novel functional renormalization group equation which takes the causal structure of space-time into account and connects the RG flows for Euclidean and Lorentzian signature by a Wick rotation. Within the Einstein-Hilbert approximation, the {beta} functions of both signatures exhibit ultraviolet fixed points in agreement with asymptotic safety. Surprisingly, the two fixed points have strikingly similar characteristics, suggesting that Euclidean and Lorentzian quantum gravity belong to the same universality class at high energies.

  9. Asymptotically safe Lorentzian gravity.

    PubMed

    Manrique, Elisa; Rechenberger, Stefan; Saueressig, Frank

    2011-06-24

    The gravitational asymptotic safety program strives for a consistent and predictive quantum theory of gravity based on a nontrivial ultraviolet fixed point of the renormalization group (RG) flow. We investigate this scenario by employing a novel functional renormalization group equation which takes the causal structure of space-time into account and connects the RG flows for Euclidean and Lorentzian signature by a Wick rotation. Within the Einstein-Hilbert approximation, the β functions of both signatures exhibit ultraviolet fixed points in agreement with asymptotic safety. Surprisingly, the two fixed points have strikingly similar characteristics, suggesting that Euclidean and Lorentzian quantum gravity belong to the same universality class at high energies. PMID:21770628

  10. Lunar gravity - A harmonic analysis

    NASA Technical Reports Server (NTRS)

    Ferrari, A. J.

    1977-01-01

    A sixteenth-degree and sixteenth-order spherical harmonic lunar gravity field has been derived from the long-term Keplerian variations in the orbits of the Apollo subsatellites and Lunar Orbiter 5. This model resolves the major mascon gravity anomalies of the lunar near side and is in very good agreement with line-of-sight acceleration results. The far-side map shows the major ringed basins to be strong localized negative anomalies located in broad regions of positive gravity which correspond closely to the highlands. The rms pressure levels calculated from equivalent-surface height variations show that the moon and earth support nearly equal pressures, whereas Mars is appreciably stronger. The moon appears to support larger loads than earth owing to its weaker central gravity field and perhaps a colder upper lithosphere. Significant differences between the low-degree gravity and topography spectra indicate that the longer-wavelength topographic features are isostatically compensated.

  11. Combustion Synthesis of TiB2-TiC/42CrMo4 Composites with Gradient Joint Prepared in Different High-Gravity Fields

    NASA Astrophysics Data System (ADS)

    Huang, Xuegang; Huang, Jie; Zhao, Zhongmin; Yin, Chun; Zhang, Long; Wu, Junyan

    2015-12-01

    The novel TiB2-TiC/42CrMo4-laminated composite materials were successfully fabricated by combustion synthesis in different high-gravity fields. This ceramic/metal composite material possesses continuously graded composition, and multilevel gradient microstructure, which is composed of TiB2-TiC ceramic substrate, ceramic-based intermediate layer, metal-based intermediate layer, and 42CrMo4 substrate. The ceramic-based intermediate layer is the main gradient transition region in the joint which shows that the TiB2 and TiC grains decrease gradually in size and volume fraction from the ceramic substrate to metal substrate. The experiment reveals that the increased high-gravity field not only leads to the higher combustion temperature and the remarkable thermal explosion mode, but also attributes to the enhanced interdiffusion and convection between the molten steel surface and liquid TiB2-based ceramic. So, the reliable fusion bonding of TiB2-TiC/42CrMo4 composite materials is achieved. Moreover, the phase separation and forced filling effect of high-gravity field is the key to improve the densification and bond performance of the joint. The ceramic/metal joint in the continuous gradient composition and microstructure represents not only the transitional change of Vickers hardness, but also the high shear bond strength of 420 25 MPa.

  12. Numerical simulation of the long-range propagation of gravity wave packets at high latitudes

    NASA Astrophysics Data System (ADS)

    Heale, C. J.; Snively, J. B.; Hickey, M. P.

    2014-10-01

    We use a 2-D, nonlinear, time-dependent numerical model to simulate the propagation of wave packets under average high latitude, winter conditions. We investigate the ability of waves to propagate large horizontal distances, depending on their direction of propagation relative to the average modeled ambient winds. Wave sources were specified to represent the following: (1) the most common wave parameters inferred from observations of Nielsen et al. (2009) (18 km ?x, 7.5 min period), (2) waves consistent with the average phase speed observed (40 m/s) but outlying horizontal wavelength and period values (40 km ?x, 17 min period), and (3) waves which would be subject to strong ducting as suggested by Snively et al. (2013) (25 km ?x, 6.7 min period). We find that wave energy density was sustained over large horizontal distances for waves ducted in the stratosphere. Waves traveling against winds in the upper stratosphere/lower mesosphere are more likely to be effectively ducted in the stratosphere and travel large horizontal distances, while waves which escape in the form of leakage are more likely to be freely propagating above 80 km altitude. Waves propagating principally in the direction of the stratopause winds are subject to weaker stratospheric ducting and thus increased leakage of wave energy density from the stratosphere. However, these waves are more likely to be subject to reflection and ducting at altitudes above 80 km based upon the average winds chosen. The wave periods that persist at late times in both the stratosphere and the mesosphere and lower thermosphere (MLT) range from 6.8 to 8 min for cases (1) and (3). Shorter-period waves tend to become trapped in the stratosphere, while longer-period waves can dissipate in the thermosphere with little reflection or trapping. It is suggested that the most common scenario is of partial ducting, where waves are observed in the airglow after they leak out of the stratosphere, especially at large horizontal distances from the source. Stratospheric ducting and associated leakage can contribute to a periodic and horizontally distributed forcing of the MLT.

  13. Crustal vertical motion along a profile crossing the Rhine graben from the Vosges to the Black Forest Mountains: Results from absolute gravity, GPS and levelling observations

    NASA Astrophysics Data System (ADS)

    Amalvict, M.; Hinderer, J.; Rzsa, S.

    2006-01-01

    The Rhine plain is oriented north-south and limited by the Vosges Mountains (France) to the West and the Black Forest Mountains (Germany) to the East. The present-day tectonic evolution of this system is not well known and many questions are still pending: is the graben subsiding? Are the mountains uplifting? What is the relative behaviour of the three different geological components? In attempting to answer these questions, we compare for the first time in this region time series of absolute gravity (AG) measurements to the available GPS observations at three sites along a profile crossing the Rhine graben. Our reference station is the gravimetric observatory near Strasbourg (J9), located in the Rhine plain where AG measurements are performed regularly since 1997 and where superconducting gravimeter (SG) observations are available almost continuously for 17 years. The secondary sites are the Welschbruch station in the Vosges Mountains where six AG measurements have been conducted since 1997 and the Black Forest Observatory (BFO) where three AG measurements are available. GPS permanent receivers are collocated at the Strasbourg-J9 site since 1999, at the Welschbruch station since 2000, and at BFO since 2002. Levelling data are only available in the BFO region. We compare the long term content of two types of geodetic measurements with special emphasis on the trend despite the limited duration of our data sets. Assuming that the gravity changes are linear in time, we obtain g?=1.90.2 ?Gal/yr at Strasbourg-J9, g?=-0.960.2 ?Gal/yr at Welschbruch site and g?=2.50.5 ?Gal/yr at BFO. The trends according to GPS observations are, respectively: -1.51 0.07 and -0.74 0.10 mm/yr at Strasbourg-J9 and Welschbruch site, respectively; there is no GPS result available at BFO. The AG results for BFO are very questionable, as well as the GPS observations at the Welschbruch station. Nonetheless, Strasbourg-J9 and Welschbruch AG measurements lead to subsidence and uplift, respectively, which are expected results in agreement with GPS at Strasbourg-J9.

  14. Solidifying Cast Iron in Low Gravity

    NASA Technical Reports Server (NTRS)

    Hendrix, J. C.; Curreri, P. A.; Stefanescu, D. M.

    1986-01-01

    Report describes study of solidification of cast iron in low and normal gravity. Because flotation, sedimentation, and convection suppressed, alloys that solidify at nearly zero gravity have unusual and potentially useful characteristics. Study conducted in airplane that repeatedly flew along parabolic trajectories. Appears iron/carbon alloys made at low gravity have greater carbon content (as high as 5 to 10 percent) than those made of Earth gravity because carbon particles do not float to top of melt.

  15. High-level simulation of an electrostatic micromotor

    NASA Astrophysics Data System (ADS)

    Endemano, Aitor; Dunnigan, Matthew; Desmulliez, Marc P.

    2001-04-01

    To date, electrostatic microactuators have mostly bee simulated using tools that involve accurate but complex finite element analysis methods. When such an analysis forms part of a full electro-mechanical simulation, the quantity of computations necessary is excessively demanding whenever rapid results are required. High-level simulation of electrostatic actuation that includes closed-form expressions of the static and dynamic behaviors of the device, seems a best alternative for rapid prototyping. The work presented in this article is focused on the high-level simulation of a particular class of actuators, the wobble electrostatic micromotor. The high-level simulation of the motor and its surrounding electronics (control loop, power supply, sensory circuitry) shows aspects of its performance that cannot be seen by any other means. As in conventional electronic systems, this approach also offers a faster and cheaper way of designing and debugging system models, by exchanging Intellectual Property blocks across different designer teams.

  16. Imaging and Analysis of Void-defects in Solder Joints Formed in Reduced Gravity using High-Resolution Computed Tomography

    NASA Technical Reports Server (NTRS)

    Easton, John W.; Struk, Peter M.; Rotella, Anthony

    2008-01-01

    As a part of efforts to develop an electronics repair capability for long duration space missions, techniques and materials for soldering components on a circuit board in reduced gravity must be developed. This paper presents results from testing solder joint formation in low gravity on a NASA Reduced Gravity Research Aircraft. The results presented include joints formed using eutectic tin-lead solder and one of the following fluxes: (1) a no-clean flux core, (2) a rosin flux core, and (3) a solid solder wire with external liquid no-clean flux. The solder joints are analyzed with a computed tomography (CT) technique which imaged the interior of the entire solder joint. This replaced an earlier technique that required the solder joint to be destructively ground down revealing a single plane which was subsequently analyzed. The CT analysis technique is described and results presented with implications for future testing as well as implications for the overall electronics repair effort discussed.

  17. Gravity Modeling for Variable Fidelity Environments

    NASA Technical Reports Server (NTRS)

    Madden, Michael M.

    2006-01-01

    Aerospace simulations can model worlds, such as the Earth, with differing levels of fidelity. The simulation may represent the world as a plane, a sphere, an ellipsoid, or a high-order closed surface. The world may or may not rotate. The user may select lower fidelity models based on computational limits, a need for simplified analysis, or comparison to other data. However, the user will also wish to retain a close semblance of behavior to the real world. The effects of gravity on objects are an important component of modeling real-world behavior. Engineers generally equate the term gravity with the observed free-fall acceleration. However, free-fall acceleration is not equal to all observers. To observers on the sur-face of a rotating world, free-fall acceleration is the sum of gravitational attraction and the centrifugal acceleration due to the world's rotation. On the other hand, free-fall acceleration equals gravitational attraction to an observer in inertial space. Surface-observed simulations (e.g. aircraft), which use non-rotating world models, may choose to model observed free fall acceleration as the gravity term; such a model actually combines gravitational at-traction with centrifugal acceleration due to the Earth s rotation. However, this modeling choice invites confusion as one evolves the simulation to higher fidelity world models or adds inertial observers. Care must be taken to model gravity in concert with the world model to avoid denigrating the fidelity of modeling observed free fall. The paper will go into greater depth on gravity modeling and the physical disparities and synergies that arise when coupling specific gravity models with world models.

  18. Radon action level for high-rise buildings.

    PubMed

    Leung, J K; Tso, M Y; Ho, C W

    1999-05-01

    Radon and its progeny are the major contributors to the natural radiation dose received by human beings. Many countries and radiological authorities have recommended radon action levels to limit the indoor radon concentrations and, hence, the annual doses to the general public. Since the sources of indoor radon and the methods for reducing its concentration are different for different types of buildings, social and economic factors have to be considered when setting the action level. But so far no action levels are specifically recommended for cities that have dwellings and offices all housed in high-rise buildings. In this study, an optimization approach was used to determine an action level for high-rise buildings based on data obtained through previous territory-wide radon surveys. A protection cost of HK$0.044 per unit fresh air change rate per unit volume and a detriment cost of HK$120,000 per person-Sv were used, which gave a minimum total cost at an action level of 200 Bq m(-3). The optimization analyses were repeated for different simulated radon distributions and living environment, which resulted in quite significantly different action levels. Finally, an action level of 200 Bq m(-3) was recommended for existing buildings and 150 Bq m(-3) for newly built buildings. PMID:10201568

  19. Time variable Earth's gravity field from SLR satellites

    NASA Astrophysics Data System (ADS)

    So?nica, Krzysztof; Jggi, Adrian; Meyer, Ulrich; Thaller, Daniela; Beutler, Gerhard; Arnold, Daniel; Dach, Rolf

    2015-10-01

    The time variable Earth's gravity field contains information about the mass transport within the system Earth, i.e., the relationship between mass variations in the atmosphere, oceans, land hydrology, and ice sheets. For many years, satellite laser ranging (SLR) observations to geodetic satellites have provided valuable information of the low-degree coefficients of the Earth's gravity field. Today, the Gravity Recovery and Climate Experiment (GRACE) mission is the major source of information for the time variable field of a high spatial resolution. We recover the low-degree coefficients of the time variable Earth's gravity field using SLR observations up to nine geodetic satellites: LAGEOS-1, LAGEOS-2, Starlette, Stella, AJISAI, LARES, Larets, BLITS, and Beacon-C. We estimate monthly gravity field coefficients up to degree and order 10/10 for the time span 2003-2013 and we compare the results with the GRACE-derived gravity field coefficients. We show that not only degree-2 gravity field coefficients can be well determined from SLR, but also other coefficients up to degree 10 using the combination of short 1-day arcs for low orbiting satellites and 10-day arcs for LAGEOS-1/2. In this way, LAGEOS-1/2 allow recovering zonal terms, which are associated with long-term satellite orbit perturbations, whereas the tesseral and sectorial terms benefit most from low orbiting satellites, whose orbit modeling deficiencies are minimized due to short 1-day arcs. The amplitudes of the annual signal in the low-degree gravity field coefficients derived from SLR agree with GRACE K-band results at a level of 77 %. This implies that SLR has a great potential to fill the gap between the current GRACE and the future GRACE Follow-On mission for recovering of the seasonal variations and secular trends of the longest wavelengths in gravity field, which are associated with the large-scale mass transport in the system Earth.

  20. High Level Waste (HLW) Feed Process Control Strategy

    SciTech Connect

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  1. High level radioactive waste management facility design criteria

    SciTech Connect

    Sheikh, N.A.; Salaymeh, S.R.

    1993-10-01

    This paper discusses the engineering systems for the structural design of the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). At the DWPF, high level radioactive liquids will be mixed with glass particles and heated in a melter. This molten glass will then be poured into stainless steel canisters where it will harden. This process will transform the high level waste into a more stable, manageable substance. This paper discuss the structural design requirements for this unique one of a kind facility. A special emphasis will be concentrated on the design criteria pertaining to earthquake, wind and tornado, and flooding.

  2. Final report on cermet high-level waste forms

    SciTech Connect

    Kobisk, E.H.; Quinby, T.C.; Aaron, W.S.

    1981-08-01

    Cermets are being developed as an alternate method for the fixation of defense and commercial high level radioactive waste in a terminal disposal form. Following initial feasibility assessments of this waste form, consisting of ceramic particles dispersed in an iron-nickel base alloy, significantly improved processing methods were developed. The characterization of cermets has continued through property determinations on samples prepared by various methods from a variety of simulated and actual high-level wastes. This report describes the status of development of the cermet waste form as it has evolved since 1977. 6 tables, 18 figures.

  3. Particulate pollution levels in Katowice, a highly industrialized polish city

    NASA Astrophysics Data System (ADS)

    Pastuszka, Jozef; Hlawiczka, Stanislaw; Willeke, Klaus

    Particulate measurements made in Katowice, Poland, in 1989 (prior to political changes in Eastern Europe and the resulting decrease in industrial production) indicate total suspended particulate levels that are 3-10 times higher than in other European cities. The concentrations of cadmium, nickel and manganese were also significantly higher than in other places in Europe. However, lead concentrations were comparable to European cities with high automobile traffice. The modes and concentration levels of the Katowice aerosol were highly direction dependent, which indicates that most of the sampled particles were locally or regionally emitted into the atmosphere.

  4. Selection of artificial gravity by animals during suborbital rocket flights

    NASA Technical Reports Server (NTRS)

    Lange, K. O.; Belleville, R. E.; Clark, F. C.

    1975-01-01

    White rats selected preferred artificial gravity levels by locomotion in centrifuges consisting of two runways mounted in the nose of sounding rockets. Roll rate of the Aerobee 150A rocket was designed to produce an angular velocity of 45 rpm during 5 min of free-fall, providing a gravity range from 0.3 to 1.5 G depending on a subject's runway position. One animal was released at the high and one at the low gravity position in each flight. Animal positions were continuously recorded. Locomotion patterns during these flights were similar. All four animals explored the entire available G-range. One rat settled at 0.4 G after 2 min; the others crossed the 1-G location in progressively narrower excursions and were near earth gravity at the end of the test period. Tentatively, the data suggest that normal earth-reared rats select earth gravity when available magnitudes include values above and below 1 G. Modification of gravity preference by prolonged exposure to higher or lower levels remains a possibility.

  5. Heat and Momentum Transfer Studies in High Reynolds Number Wavy Films at Normal and Reduced Gravity Conditions

    NASA Technical Reports Server (NTRS)

    Balakotaiah, V.

    1996-01-01

    We examined the effect of the gas flow on the liquid film when the gas flows in the countercurrent direction in a vertical pipe at normal gravity conditions. The most dramatic effect of the simultaneous flow of gas and liquid in pipes is the greatly increased transport rates of heat, mass, and momentum. In practical situations this enhancement can be a benefit or it can result in serious operational problems. For example, gas-liquid flow always results in substantially higher pressure drop and this is usually undesirable. However, much higher heat transfer coefficients can be expected and this can obviously be of benefit for purposes of design. Unfortunately, designers know so little of the behavior of such two phase systems and as a result these advantages are not utilized. Due to the complexity of the second order boundary model as well as the fact that the pressure variation across the film is small compared to the imposed gas phase pressure, the countercurrent gas flow affect was studied for the standard boundary layer model. A different stream function that can compensate the shear stress affect was developed and this stream function also can predict periodic solutions. The discretized model equations were transformed to a traveling wave coordinate system. A stability analysis of these sets of equations showed the presence of a Hopf bifurcation for certain values of the traveling wave velocity and the shear stress. The Hopf celerity was increased due to the countercurrent shear. For low flow rate the increases of celerity are more than for the high flow rate, which was also observed in experiments. Numerical integration of a traveling wave simplification of the model also predicts the existence of chaotic large amplitude, nonperiodic waves as observed in the experiments. The film thickness was increased by the shear.

  6. A controlled-source seismic and gravity study of the High Lava Plains (HLP) of Eastern Oregon

    NASA Astrophysics Data System (ADS)

    Cox, Catherine; Keller, G. Randy; Harder, Steven H.

    2013-12-01

    This study employs data collected during the High Lava Plains (HLP) controlled-source seismic experiment conducted in September 2008. In this experiment, 2612 short-period seismic recorders and 120 3-component recorders were deployed across eastern Oregon and adjacent parts of Nevada and Idaho to record 15 seismic sources. Seismic and gravity data were integrated to create 2-D crustal scale P-wave velocity and density models for the 400 km long NW-SE and N-S profiles to provide a better understanding of the crustal and upper mantle structure and ultimately the magmatic and tectonic evolution of the region. These models are the first high-resolution images beneath the path of migratory, bi-modal volcanism that dotted the High Lava Plains beginning at 16 Ma. Our models show that the crustal structure across the HLP region is similar to that of the northern Basin and Range which has experienced extension since 35 Ma but with moderate magmatic modification of the crust. A thick layer (5-7 km) of sediments and volcanics extends over most of the area and is thickest in the Harney Basin area. We interpret denser/faster material in the lower to middle crust under the southern Harney Basin area to be mafic intraplating. We have also identified a region of denser/faster material in the upper crust in the vicinity of Oregon-Idaho border. The crust thickens from 34 to 37 km, and the lower crust increases in density (2.8-2.85 g/cm3), from west to east across eastern Oregon in close proximity to the interpreted position of the 0.706 Sr isotope line, suggesting a decrease in extension. In the lowermost crust below the southeastern HLP, there is relatively high velocity (7.2-7.4 km/s) and density (2.95 g/cm3) that suggests the presence of underplating. The HLP region has undergone moderate extension, and the average crustal velocity is somewhat higher than in the adjacent Basin and Range, suggesting some magmatic modification in the lower crust, but not as much as might be expected given the voluminous surface volcanism.

  7. Low voltage to high voltage level shifter and related methods

    NASA Technical Reports Server (NTRS)

    Mentze, Erik J. (Inventor); Hess, Herbert L. (Inventor); Buck, Kevin M. (Inventor); Cox, David F. (Inventor)

    2006-01-01

    A shifter circuit comprises a high and low voltage buffer stages and an output buffer stage. The high voltage buffer stage comprises multiple transistors arranged in a transistor stack having a plurality of intermediate nodes connecting individual transistors along the stack. The transistor stack is connected between a voltage level being shifted to and an input voltage. An inverter of this stage comprises multiple inputs and an output. Inverter inputs are connected to a respective intermediate node of the transistor stack. The low voltage buffer stage has an input connected to the input voltage and an output, and is operably connected to the high voltage buffer stage. The low voltage buffer stage is connected between a voltage level being shifted away from and a lower voltage. The output buffer stage is driven by the outputs of the high voltage buffer stage inverter and the low voltage buffer stage.

  8. Cohomological gravity

    SciTech Connect

    Birmingham, D. ); Rakowski, M. )

    1993-07-01

    In the present work, the authors construct a theory of cohomological gravity in arbitrary dimensions based upon a local vector supersymmetry algebra. The observables in this theory are polynomial, but generally non-local operators, and have a natural interpretation in terms of a universal bundle for gravity. As such, their correlation functions correspond to cohomology classes on moduli spaces of Riemannian connections. In this uniformization approach, different moduli spaces are obtained by introducing curvature singularities on codimension two submanifolds via a puncture operator. This puncture operator is constructed from a naturally occurring differential form of co-degree two in the theory, and the authors are led to speculate on connections between this continuum quantum field theory, and the discrete Regge calculus. 16 refs.

  9. Quantum gravity

    SciTech Connect

    Markov, M.A.; West, P.C.

    1984-01-01

    This book discusses the state of the art of quantum gravity, quantum effects in cosmology, quantum black-hole physics, recent developments in supergravity, and quantum gauge theories. Topics considered include the problems of general relativity, pregeometry, complete cosmological theories, quantum fluctuations in cosmology and galaxy formation, a new inflationary universe scenario, grand unified phase transitions and the early Universe, the generalized second law of thermodynamics, vacuum polarization near black holes, the relativity of vacuum, black hole evaporations and their cosmological consequences, currents in supersymmetric theories, the Kaluza-Klein theories, gauge algebra and quantization, and twistor theory. This volume constitutes the proceedings of the Second Seminar on Quantum Gravity held in Moscow in 1981.

  10. Modeling future high-resolution dynamic sea level change

    NASA Astrophysics Data System (ADS)

    Brunnabend, Sandra-Esther; Dijkstra, Henk A.; Kliphuis, Michael A.; van Werkhoven, Ben; Bal, Henri E.; van Meersbergen, Maarten; Seinstra, Frank; Maassen, Jason

    2015-04-01

    Different studies have shown that resolving ocean eddies and representing boundary currents are of major importance when simulating changes in dynamic sea level on regional scale. Therefore, we use the strongly eddying global model version of the Parallel Ocean Program to simulate high-resolution future (up to the year 2100) sea surface height variations (SSH) under the SRES-A1B atmospheric forcing scenario. Results show dynamic sea level changes in the Southern Ocean that are caused by the southward shift in the westerly winds. The warming ocean (global mean sea surface temperature rises by about 2C over the period 2000-2100) leads to a strong reduction of the Atlantic Meridional Overturning Circulation (AMOC). The magnitude of this reduction is affected by a feedback involving the heat transport to the sub-polar gyre region and evaporation over the North Atlantic region. The ocean circulation changes cause regional deviations from global mean sea level change in the North Atlantic. At coastal regions of eastern North America, dynamic sea level change leads to a positive deviation from global mean sea level change in the order of several decimeters. In the sub-polar gyre region a negative deviation from global mean sea level occurs. In the western North Atlantic, not only mean regional sea level is changed but also its variability, caused by shifted eddy pathways. This leads to a change in the frequency distribution of SSH anomalies, which has important consequences for regional sea level extremes.

  11. The tracking of high level waste shipments-TRANSCOM system

    SciTech Connect

    Johnson, P.E.; Joy, D.S.; Pope, R.B.

    1995-12-31

    The TRANSCOM (transportation tracking and communication) system is the U.S. Department of Energy`s (DOE`s) real-time system for tracking shipments of spent fuel, high-level wastes, and other high-visibility shipments of radioactive material. The TRANSCOM system has been operational since 1988. The system was used during FY1993 to track almost 100 shipments within the US.DOE complex, and it is accessed weekly by 10 to 20 users.

  12. High levels of fluctuating asymmetry in isolated stickleback populations

    PubMed Central

    2012-01-01

    Background Fluctuating asymmetry (FA), defined as small random deviations from the ideal bilateral symmetry, has been hypothesized to increase in response to both genetic and environmental stress experienced by a population. We compared levels of FA in 12 bilateral meristic traits (viz. lateral-line system neuromasts and lateral plates), and heterozygosity in 23 microsatellite loci, among four marine (high piscine predation risk) and four pond (zero piscine predation risk) populations of nine-spined sticklebacks (Pungitius pungitius). Results Pond sticklebacks had on average three times higher levels of FA than marine fish and this difference was highly significant. Heterozygosity in microsatellite markers was on average two times lower in pond (HE ? 0.3) than in marine (HE ? 0.6) populations, and levels of FA and heterozygosity were negatively correlated across populations. However, after controlling for habitat effect on heterozygosity, levels of FA and heterozygosity were uncorrelated. Conclusions The fact that levels of FA in traits likely to be important in the context of predator evasion were elevated in ponds compared to marine populations suggests that relaxed selection for homeostasis in ponds lacking predatory fish may be responsible for the observed habitat difference in levels of FA. This inference also aligns with the observation that the levels of genetic variability across the populations did not explain population differences in levels of FA after correcting for habitat effect. Hence, while differences in strength of selection, rather than in the degree of genetic stress could be argued to explain habitat differences in levels of FA, the hypothesis that increased FA in ponds is caused by genetic stress cannot be rejected. PMID:22788717

  13. Gravity quantized: Loop quantum gravity with a scalar field

    SciTech Connect

    Domagala, Marcin; Kaminski, Wojciech; Giesel, Kristina; Lewandowski, Jerzy

    2010-11-15

    ...''but we do not have quantum gravity.'' This phrase is often used when analysis of a physical problem enters the regime in which quantum gravity effects should be taken into account. In fact, there are several models of the gravitational field coupled to (scalar) fields for which the quantization procedure can be completed using loop quantum gravity techniques. The model we present in this paper consists of the gravitational field coupled to a scalar field. The result has similar structure to the loop quantum cosmology models, except that it involves all the local degrees of freedom of the gravitational field because no symmetry reduction has been performed at the classical level.

  14. Is nonrelativistic gravity possible?

    SciTech Connect

    Kocharyan, A. A.

    2009-07-15

    We study nonrelativistic gravity using the Hamiltonian formalism. For the dynamics of general relativity (relativistic gravity) the formalism is well known and called the Arnowitt-Deser-Misner (ADM) formalism. We show that if the lapse function is constrained correctly, then nonrelativistic gravity is described by a consistent Hamiltonian system. Surprisingly, nonrelativistic gravity can have solutions identical to relativistic gravity ones. In particular, (anti-)de Sitter black holes of Einstein gravity and IR limit of Horava gravity are locally identical.

  15. Typewriter Modifications for Persons Who Are High-Level Quadriplegics.

    ERIC Educational Resources Information Center

    O'Reagan, James R.; And Others

    Standard, common electric typewriters are not completely suited to the needs of a high-level quadriplegic typing with a mouthstick. Experiences show that for complete control of a typewriter a mouthstick user needs the combined features of one-button correction, electric forward and reverse indexing, and easy character viewing. To modify a…

  16. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.30...

  17. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.30...

  18. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.30...

  19. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true High-level radioactive waste. 227.30 Section 227.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.30...

  20. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Definitions § 227.30...

  1. MIXING PROCESSES IN HIGH-LEVEL WASTE TANKS

    EPA Science Inventory

    Flammable gases can be generated in DOE high-level waste tanks, including radiolytic hydrogen, and during cesium precipitation from salt solutions, benzene. Under normal operating conditions the potential for deflagration or detonation from these gases is precluded by purging and...

  2. Equity-Focused Schools Carry All Students to High Levels

    ERIC Educational Resources Information Center

    WestEd, 2014

    2014-01-01

    Despite decades of experience supporting efforts from local to state levels to improve learning for underserved students, Sonia Caus Gleason and WestEd's Nancy Gerzon could not point to examples of entire schools accomplishing what they believed was possible: high-poverty public schools personalizing learning for all students to consistently reach…

  3. High-Level waste process and product data annotated bibliography

    SciTech Connect

    Stegen, G.E.

    1996-02-13

    The objective of this document is to provide information on available issued documents that will assist interested parties in finding available data on high-level waste and transuranic waste feed compositions, properties, behavior in candidate processing operations, and behavior on candidate product glasses made from those wastes. This initial compilation is only a partial list of available references.

  4. Device enables calibration of microphones at high sound pressure levels

    NASA Technical Reports Server (NTRS)

    Gillen, A.

    1967-01-01

    Coupling device accurately calibrates microphones at high sound pressure intensities. The system which uses a liquid as the coupling medium can operate in an automatic mode by using a standard microphone as a control sensor. Feedback from the standard microphone controls the calibration signal level.

  5. THE XAL INFRASTRUCTURE FOR HIGH LEVEL CONTROL ROOM APPLICATIONS

    SciTech Connect

    Shishlo, Andrei P; Allen, Christopher K; Chu, Paul; Galambos, John D; Pelaia II, Tom

    2009-01-01

    XAL is a Java programming framework for building high-level control applications related to accelerator physics. The structure, details of implementation, and interaction between components, auxiliary XAL packages, and the latest modifications are discussed. A general overview of XAL applications created for the SNS project is presented.

  6. High level cognitive information processing in neural networks

    NASA Technical Reports Server (NTRS)

    Barnden, John A.; Fields, Christopher A.

    1992-01-01

    Two related research efforts were addressed: (1) high-level connectionist cognitive modeling; and (2) local neural circuit modeling. The goals of the first effort were to develop connectionist models of high-level cognitive processes such as problem solving or natural language understanding, and to understand the computational requirements of such models. The goals of the second effort were to develop biologically-realistic model of local neural circuits, and to understand the computational behavior of such models. In keeping with the nature of NASA's Innovative Research Program, all the work conducted under the grant was highly innovative. For instance, the following ideas, all summarized, are contributions to the study of connectionist/neural networks: (1) the temporal-winner-take-all, relative-position encoding, and pattern-similarity association techniques; (2) the importation of logical combinators into connection; (3) the use of analogy-based reasoning as a bridge across the gap between the traditional symbolic paradigm and the connectionist paradigm; and (4) the application of connectionism to the domain of belief representation/reasoning. The work on local neural circuit modeling also departs significantly from the work of related researchers. In particular, its concentration on low-level neural phenomena that could support high-level cognitive processing is unusual within the area of biological local circuit modeling, and also serves to expand the horizons of the artificial neural net field.

  7. The Estuary Guide. Level 3: High School. Draft.

    ERIC Educational Resources Information Center

    Alexander, Glen; And Others

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

  8. Teaching for Higher Cognitive Level Learning in High School Science.

    ERIC Educational Resources Information Center

    Fraser, Barry J.

    Designed to focus on teaching for higher-level cognitive learning, this study measured student perceptions of psychosocial aspects of their classroom learning and involved a team of six researchers. The study consisted of an intensive 10-week investigation of two above-average science teachers in a suburban high school in Perth, Western Australia.

  9. Airborne Gravity Gradiometry Resolves a Full Range of Gravity Frequencies

    NASA Astrophysics Data System (ADS)

    Mataragio, J.; Brewster, J.; Mims, J.

    2007-12-01

    Airborne Full Tensor Gradiometry (Air\\-FTGR) was flown at high altitude coincident with Airborne Gravity (AG) flown in 2003 in West Arnhem Land, Australia. A preliminary analysis of two data sets indicates that the Air\\-FTGR system has the capability of resolving intermediate to long wavelengths features that may be associated with relatively deeper geological structures. A comparison of frequency filtered slices and power spectral density (PSD) for both data sets using the short (> 5 km), intermediate (10 km) and long (20 km) wavelengths reveals that high altitude Air\\-FTGR data show greater response in high frequency anomalies than a conventional Airborne Gravity and matches well with the AG even at the longest wavelengths anomalies. The effect of line spacing and target resolution was examined between the two data sets. Reprocessed gradient and AG data at 2, 4 and 6 km line spacing suggest that Air\\-FTGR could be effectively flown at a comparatively wider line spacing to resolve similar targets the AG would resolve with tighter line spacing. Introduction Airborne Full Tensor Gradiometry (Air\\-FTGR) data have been available to the mining industry since 2002 and their use for geologic applications is well established. However, Air\\-FTGR data has been mostly considered and used in mapping and delineation of near surface geological targets. This is due to the fact that gravity gradiometer measurements are well suited to capture the high frequency signal associated with near\\-surface targets ( Li, 2001). This is possible because the gradiometer signal strength falls off with the cube of the distance to the target. Nonetheless, in recent years there has been an increasing demand from the mining, oil, and gas industry in utilizing Full Tensor Gravity Gradiometer as a mapping tool for both regional and prospect level surveys. Air\\-FTGR as a Regional Mapping Tool Several, relatively low altitude surveys have been successfully flown in Brazil, Canada and Australia mostly targeting large, regional\\- scale crustal structures as well as regional mapping of both lithology and regolith. Air\\-FTGR mapping is especially effective in areas of thick lateritic and/or clay cover where other geophysical methods such as airborne magnetics or electromagnetics become less effective. For instance, an Air\\-FTGR survey was successfully flown in Brazil in the Province of Minas Gerais, where several crustal\\-scale structures associated with iron oxide mineralization were identified ( Mataragio et. al., 2006). In addition, in 2006 Air\\-FTGR had good success in the regional mapping of structures associated with Iron Oxide Copper Gold (IOCG) and uranium mineralization in the Wernecke Mountains in the Yukon, and Northwest Territories, Canada. On the basis of these successful surveys, Bell Geospace has initiated a number of high altitude test surveys aiming at evaluating the performance of the Air\\-FTGR system in capturing low frequency signal that may be associated with regional\\-scale, deeper structures. One of the test surveys was conducted in December of 2006 in Australia, where the performance of Air\\-FTGR and the conventional Airborne Gravity were evaluated. Airborne gravity is currently considered well suited for capturing low frequency signal.

  10. Model studies of time-dependent ducting for high-frequency gravity waves and associated airglow responses in the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Yu, Yonghui

    This doctoral dissertation has mainly concentrated on modeling studies of shorter period acoustic-gravity waves propagating in the upper atmosphere. Several cases have been investigated in the literature, which are focusing on the propagation characteristics of highfrequency gravity wave packets. The dissertation consists of five main divisions of which each has its own significance to be addressed, and these five chapters are also bridged in order with each other to present a theme about gravity wave ducting dynamics, energetics, and airglows. The first chapter is served as an introduction of the general topic about atmospheric acoustic-gravity waves. Some of the historical backgrounds are provided as an interesting refreshment and also as a motivation reasoning this scientific research for decades. A new 2-D, time-dependent, and nonlinear model is introduced in the second chapter (the AGE-TIP model, acronymically named atmospheric gravity waves for the Earth plus tides and planetary waves). The model is developed during this entire doctoral study and has carried out almost all research results in this dissertation. The third chapter is a model application for shorter period gravity waves ducted in a thermally stratified atmosphere. In spite of mean winds the thermal ducting occurs because ducted waves are fairly common occurrences in airglow observations. One-dimensional Fourier analysis is applied to identify the ducted wave modes that reside within multiple thermal ducts. Besides, the vertical energy flux and the wave kinetic energy density are derived as wave diagnostic variables to better understand the time-resolved vertical transport of wave energy in the presence of multiple thermal ductings. The fourth chapter is also a model application for shorter period gravity waves, but it instead addresses the propagation of high-frequency gravity waves in the presence of mean background wind shears. The wind structure acts as a significant directional filter to the wave spectra and hence causes noticeable azimuthal variations at higher altitudes. In addition to the spectral analysis applied previously the wave action has been used to interpret the energy coupling between the waves and the mean flow among some atmospheric regions, where the waves are suspected to extract energy from the mean flow at some altitudes and release it to other altitudes. The fifth chapter is a concrete and substantial step connecting theoretical studies and realistic observations through nonlinearly coupling wave dynamic model with airglow chemical reactions. Simulated O (1S) (557.7 nm) airglow images are provided so that they can be compared with observational airglow images. These simulated airglow brightness variations response accordingly with minor species density fluctuations, which are due to propagating and ducting nonlinear gravity waves within related airglow layers. The thermal and wind structures plus the seasonal and geographical variabilities could significantly influence the observed airglow images. By control modeling studies the simulations can be used to collate with concurrent observed data, so that the incoherencies among them could be very useful to discover unknown physical processes behind the observed wave scenes.

  11. Directional solidification of Cu-Pb and Bi-Ga monotectic alloys under normal gravity and during parabolic flight

    NASA Technical Reports Server (NTRS)

    Dhindaw, B. K.; Stefanescu, D. M.; Singh, A. K.; Curreri, P. A.

    1988-01-01

    Cu-Pb and Bi-Ga monotectic alloys of nominal hypermonotectic compositions were directionally solidified under various furnace translation rates, temperature gradients, and gravity levels. Gravity was varied by solidifying the alloys under ground conditions and in the furnace aboard NASA KC-135 aircraft, flying on parabolic trajectories. High translation rates, high gradients, high gravity levels, and higher density and lower thermal conductivity of the L2 phase favored the formation of fiber composite structure, while the opposite conditions resulted in structures consisting of L2 droplets in alpha matrix. A modified particle engulfment theory as originally enunciated by Ulhmann et al. (1964) is proposed to explain these observations.

  12. Geoid for Austria - Regional gravity FIELD improved

    NASA Astrophysics Data System (ADS)

    Rieser, Daniel; Pock, Christian; Mayer-Gürr, Torsten; Kühtreiber, Norbert

    2013-04-01

    The project 'Geoid for Austria - Regional gravity FIELD improved' (GARFIELD) is a current initiative for the generation of a new high-quality gravity field solution for the Austrian region, which overcomes the inconsistencies between previous geoid solutions and geoid heights from GPS/leveling campaigns. The optimum combination of the complementary data types of satellite observations and all available terrestrial gravity field measurements in Austria and neighbouring countries will be essential. The Least Squares Collocation (LSC) approach will serve as reference method for the gravity field computation. In this context, GOCE gradients should be used as in-situ observations. Alternatively to LSC, a Gauss-Markov model with parametrization as Radial Basis Functions will be implemented. For a successful data combination, the Remove-Compute-Restore technique will be revised to avoid a double consideration of the topographic masses when performing long- and short-wavelength signal reductions. This contribution should give an overview about methods, developments and the current status of the project GARFIELD.

  13. High-accurate optical fiber liquid level sensor

    NASA Astrophysics Data System (ADS)

    Sun, Dexing; Chen, Shouliu; Pan, Chao; Jin, Henghuan

    1991-08-01

    A highly accurate optical fiber liquid level sensor is presented. The single-chip microcomputer is used to process and control the signal. This kind of sensor is characterized by self-security and is explosion-proof, so it can be applied in any liquid level detecting areas, especially in the oil and chemical industries. The theories and experiments about how to improve the measurement accuracy are described. The relative error for detecting the measurement range 10 m is up to 0.01%.

  14. Overview of high-level waste management accomplishments

    SciTech Connect

    Lawroski, H; Berreth, J R; Freeby, W A

    1980-01-01

    Storage of power reactor spent fuel is necessary at present because of the lack of reprocessing operations particularly in the U.S. By considering the above solidification and storage scenario, there is more than reasonable assurance that acceptable, stable, low heat generation rate, solidified waste can be produced, and safely disposed. The public perception of no waste disposal solutions is being exploited by detractors of nuclear power application. The inability to even point to one overall system demonstration lends credibility to the negative assertions. By delaying the gathering of on-line information to qualify repository sites, and to implement a demonstration, the actions of the nuclear power detractors are self serving in that they can continue to point out there is no demonstration of satisfactory high-level waste disposal. By maintaining the liquid and solidified high-level waste in secure above ground storage until acceptable decay heat generation rates are achieved, by producing a compatible, high integrity, solid waste form, by providing a second or even third barrier as a compound container and by inserting the enclosed waste form in a qualified repository with spacing to assure moderately low temperature disposal conditions, there appears to be no technical reason for not progressing further with the disposal of high-level wastes and needed implementation of the complete nuclear power fuel cycle.

  15. High levels of molecular chlorine in the Arctic atmosphere

    NASA Astrophysics Data System (ADS)

    Liao, Jin; Huey, L. Gregory; Liu, Zhen; Tanner, David J.; Cantrell, Chris A.; Orlando, John J.; Flocke, Frank M.; Shepson, Paul B.; Weinheimer, Andrew J.; Hall, Samuel R.; Ullmann, Kirk; Beine, Harry J.; Wang, Yuhang; Ingall, Ellery D.; Stephens, Chelsea R.; Hornbrook, Rebecca S.; Apel, Eric C.; Riemer, Daniel; Fried, Alan; Mauldin, Roy L.; Smith, James N.; Staebler, Ralf M.; Neuman, J. Andrew; Nowak, John B.

    2014-02-01

    Chlorine radicals can function as a strong atmospheric oxidant, particularly in polar regions, where levels of hydroxyl radicals are low. In the atmosphere, chlorine radicals expedite the degradation of methane and tropospheric ozone, and the oxidation of mercury to more toxic forms. Here we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We report high levels of molecular chlorine, of up to 400 pptv. Concentrations peaked in the early morning and late afternoon, and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimate that the chlorine radicals produced from the photolysis of molecular chlorine oxidized more methane than hydroxyl radicals, on average, and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyses mercury oxidation and the breakdown of tropospheric ozone. We therefore suggest that molecular chlorine exerts a significant effect on the atmospheric chemistry of the Arctic.

  16. Spatiotemporal Variations in the Diagnostics of Gravity Waves Associated with Jet/Front System and Their Correlations with GWs Revealed in High-Resolution Global Reanalysis Data

    NASA Astrophysics Data System (ADS)

    Chun, Hye-Yeong; Shin, Seok-Woo; Kim, Young-Ha

    2014-05-01

    Jet/Front system is one of the major sources of atmospheric gravity waves (GWs) that contribute significantly to global circulation in the middle atmosphere. Nevertheless, there is no comprehensive parameterization of GW drag (GWD) associated with Jet/Front system based on the formulation of the GW momentum flux at launch levels, unlike for mountain and convective GWD parameterizaitons, due primarily to uncertainties in their generation mechanisms. Although several attempts have been made to parameterize Jet/Front GWs, at this moment, only one GWD scheme that launches GWs at which the frontogenesis function (FF) is over certain threshold at mid-troposphere is utilized in a climate model (WACCM) that takes into account GWD associated with three major sources (mountain, convection, and Jet/Front) individually. In this study, we evaluate two major diagnostics of Jet/Front GWs, FF and residual of the nonlinear balance equation ( ) by examing their spatiotemporal variations using two global reanalysis data sets (MERRA and ERA-Interim) during 32 years (1980-2011), and by exmaining correlations between the diagnostics and GW momentum fluxes at 300, 70, and 5 hPa that are explicitly resolved from high-resolution (0.25o x 0.25o) reanalysis data (ECMWF) in January and July of 2007. It is found that FF and have maximum values in the mid-to-high latitudes of winter hemisphere with local maximums in Greenland, East Asia, West of North America, and Anthes Mountains in both reanalysis data sets. The GW momentum fluxes calcualted from ECMWF revealed two source regions in the upper troposphere : (i) poleward of 30o in both hemisphere with larger values in the winter hemisphere and (ii) tropical and subtropical regions in both hemispheres. The FF and are well correlated with GWs in mid-to-high latitudes follwing their seasonal variations, and this can successfully separate GWs in tropics and subtroics generated by convective sources, implicating for that the diagnostics are feasible. In the four regions of local maximums of FF and , GW momentum flux near the launch level (300 hPa) is correlated better with than FF for both January and July, except in East Asia. A parameterization of Jet/Front GWs based on the diagnotiscs of is implimented in WACCM, and a climate simulation result is compared with that of the original WACCM with a FF-based Jet/Front GWD parameterization. This also will be presented in the conference.

  17. Exponential gravity

    SciTech Connect

    Linder, Eric V.

    2009-12-15

    We investigate a f(R) modification of gravity that is exponential in the Ricci scalar R to explain cosmic acceleration. The steepness of this dependence provides extra freedom to satisfy solar system and other curvature regime constraints. With a parameter to alleviate the usual fine-tuning of having the modification strengthen near the present, the total number of parameters is only one more than {lambda}CDM. The resulting class of solutions asymptotes to w=-1 but has no cosmological constant. We calculate the dynamics in detail, examine the effect on the matter power spectrum, and provide a simple fitting form relating the two.

  18. High-level waste management technology program plan

    SciTech Connect

    Harmon, H.D.

    1995-01-01

    The purpose of this plan is to document the integrated technology program plan for the Savannah River Site (SRS) High-Level Waste (HLW) Management System. The mission of the SRS HLW System is to receive and store SRS high-level wastes in a see and environmentally sound, and to convert these wastes into forms suitable for final disposal. These final disposal forms are borosilicate glass to be sent to the Federal Repository, Saltstone grout to be disposed of on site, and treated waste water to be released to the environment via a permitted outfall. Thus, the technology development activities described herein are those activities required to enable successful accomplishment of this mission. The technology program is based on specific needs of the SRS HLW System and organized following the systems engineering level 3 functions. Technology needs for each level 3 function are listed as reference, enhancements, and alternatives. Finally, FY-95 funding, deliverables, and schedules are s in Chapter IV with details on the specific tasks that are funded in FY-95 provided in Appendix A. The information in this report represents the vision of activities as defined at the beginning of the fiscal year. Depending on emergent issues, funding changes, and other factors, programs and milestones may be adjusted during the fiscal year. The FY-95 SRS HLW technology program strongly emphasizes startup support for the Defense Waste Processing Facility and In-Tank Precipitation. Closure of technical issues associated with these operations has been given highest priority. Consequently, efforts on longer term enhancements and alternatives are receiving minimal funding. However, High-Level Waste Management is committed to participation in the national Radioactive Waste Tank Remediation Technology Focus Area. 4 refs., 5 figs., 9 tabs.

  19. High-Precise Gravity Observations at Archaeological Sites: How We Can Improve the Interpretation Effectiveness and Reliability?

    NASA Astrophysics Data System (ADS)

    Eppelbaum, Lev

    2015-04-01

    Microgravity investigations are comparatively rarely used for searching of hidden ancient targets (e.g., Eppelbaum, 2013). It is caused mainly by small geometric size of the desired archaeological objects and various types of noise complicating the observed useful signal. At the same time, development of modern generation of field gravimetric equipment allows to register microGal (10-8 m/s2) anomalies that offer a new challenge in this direction. Correspondingly, an accuracy of gravity variometers (gradientometers) is also sharply increased. How we can improve the interpretation effectiveness and reliability? Undoubtedly, it must be a multi-stage process. I believe that we must begin since nonconventional methodologies for reducing topographic effect and terrain correction computation. Topographic effect reducing The possibilities of reducing topographic effects by grouping the points of additional gravimetric observations around the central point located on the survey network were demonstrated in (Khesin et al., 1996). A group of 4 to 8 additional points is located above and below along the relief approximately symmetrically and equidistant from the central point. The topographic effect is reduced to the obtained difference between the gravity field in the center of the group and its mean value for the whole group. Application of this methodology in the gold-pyrite deposit Gyzyl-Bulakh (Lesser Caucasus, western Azerbaijan) indicated its effectiveness. Computation of terrain correction Some geophysicists compare the new ideas in the field of terrain correction (TC) in gravimetry with the 'perpetuum mobile' invention. However, when we speak about very detailed gravity observations, the problem of most optimal computation of surrounding relief influence is of a great importance. Let us will consider two approaches applied earlier in ore geophysics. First approach A first method was applied in the Gyzyl-Bulakh gold-pyrite deposit situated in the Mekhmana ore region of the Lesser Caucasus (western Azerbaijan) under conditions of rugged relief and complex geology. This deposit is well investigated by mining and drilling operations and therefore was used as a reference field polygon for testing this approach. A special scheme for obtaining the Bouguer anomalies has been employed to suppress the terrain relief effects dampening the anomaly effects from the objects of prospecting. The scheme is based on calculating the difference between the free-air anomaly and the gravity field determined from a 3D model of a uniform medium with a real topography. 3-D terrain relief model with an interval of its description of 80 km (the investigated 6 profiles of 800 m length are in the center of this interval) was employed to compute (by the use of GSFC software (Khesin et al., 1996)) the gravitational effect of the medium (σ = 2670 kg/m3). With applying such a scheme the Bouguer anomalies were obtained with accuracy in two times higher than that of TC received by the conventional methods. As a result, on the basis of the improved Bouguer gravity with the precise TC data, the geological structure of the deposit was defined (Khesin et al., 1996). Second approach Second approach was employed at the complex Katekh pyrite-polymetallic deposit, which is located at the southern slope of the Greater Caucasus (northern Azerbaijan). The main peculiarities of this area are very rugged topography of SW-NE trend, complex geology and severe tectonics. Despite the availability of conventional ΔgB (TC far zones were computed up to 200 km), for the enhanced calculation of surrounding terrain topography a digital terrain relief model was created (Eppelbaum and Khesin, 2004). The SW-NE regional topography trend in the area of the Katekh deposit occurrence was computed as a rectangular digital terrain relief model (DTRM) of 20 km long and 600 m wide (our interpretation profile with a length of 800 m was located in the geometrical center of the DTRM). As a whole, about 1000 characteristic points were used to describe the DTRM (most frequently points were focused in the center of the DTRM and more rarely - on the margins). Thus, in the interactive 3D ΔgB modeling (by the use of GSFC software) was computed effect not only from geological bodies occurring in this area, but also from surrounding DTRM. In the issue of this scheme application, two new ore bodies were discovered. Quantitative analysis of gravity anomalies The trivial formulas of quantitative analysis (based on simple relationships between the gravity field intensity and geometrical parameters of the anomalous body) are widely presented in the geophysical literature (e.g., Telford et al., 1993; Parasnis, 1997). However, absence of reliable information about the normal gravity field in the studied areas strongly limits practical application of these methods. Gravity field intensity F is expressed as F = - gradW, (1) where W is the gravity potential. For anomalous magnetic field Ua we can write (when magnetic susceptibility ≤ 0.1 SI unit) (Khesin et al., 1996): Ua = - gradV, (2) where V represents the magnetic potential. Let's consider analytical expressions of some typical models employed in magnetic and gravity fields (Table 1). Table 1. Comparison of some analytical expressions for magnetic and gravity fields Field Analytical expression MagneticThin bed (TB) z Zv = 2I2b-2--2 x + z (3) Point source (rod) mz Zv = ----3/2 (x2 + z2) (4) Gravity Horizontal Circular Cylinder (HCC) -z-- Δg = 2Gσ x2 + z2 (5) Sphere --z--- Δg = GM (x2 + z2)3/2 (6)

  20. RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS

    SciTech Connect

    Fox, K.

    2010-09-07

    High level radioactive wastes are being vitrified at the Savannah River Site for long term disposal. Many of the wastes contain sulfate at concentrations that can be difficult to retain in borosilicate glass. This study involves efforts to optimize the composition of a glass frit for combination with the waste to improve sulfate retention while meeting other process and product performance constraints. The fabrication and characterization of several series of simulated waste glasses are described. The experiments are detailed chronologically, to provide insight into part of the engineering studies used in developing frit compositions for an operating high level waste vitrification facility. The results lead to the recommendation of a specific frit composition and a concentration limit for sulfate in the glass for the next batch of sludge to be processed at Savannah River.

  1. Review of High Level Waste Tanks Ultrasonic Inspection Data

    SciTech Connect

    Wiersma, B

    2006-03-09

    A review of the data collected during ultrasonic inspection of the Type I high level waste tanks has been completed. The data was analyzed for relevance to the possibility of vapor space corrosion and liquid/air interface corrosion. The review of the Type I tank UT inspection data has confirmed that the vapor space general corrosion is not an unusually aggressive phenomena and correlates well with predicted corrosion rates for steel exposed to bulk solution. The corrosion rates are seen to decrease with time as expected. The review of the temperature data did not reveal any obvious correlations between high temperatures and the occurrences of leaks. The complex nature of temperature-humidity interaction, particularly with respect to vapor corrosion requires further understanding to infer any correlation. The review of the waste level data also did not reveal any obvious correlations.

  2. Management of data quality of high level waste characterization

    SciTech Connect

    Winters, W.I., Westinghouse Hanford

    1996-06-12

    Over the past 10 years, the Hanford Site has been transitioning from nuclear materials production to Site cleanup operations. High-level waste characterization at the Hanford Site provides data to support present waste processing operations, tank safety programs, and future waste disposal programs. Quality elements in the high-level waste characterization program will be presented by following a sample through the data quality objective, sampling, laboratory analysis and data review process. Transition from production to cleanup has resulted in changes in quality systems and program; the changes, as well as other issues in these quality programs, will be described. Laboratory assessment through quality control and performance evaluation programs will be described, and data assessments in the laboratory and final reporting in the tank characterization reports will be discussed.

  3. Nondestructive examination of DOE high-level waste storage tanks

    SciTech Connect

    Bush, S.; Bandyopadhyay, K.; Kassir, M.; Mather, B.; Shewmon, P.; Streicher, M.; Thompson, B.; van Rooyen, D.; Weeks, J.

    1995-05-01

    A number of DOE sites have buried tanks containing high-level waste. Tanks of particular interest am double-shell inside concrete cylinders. A program has been developed for the inservice inspection of the primary tank containing high-level waste (HLW), for testing of transfer lines and for the inspection of the concrete containment where possible. Emphasis is placed on the ultrasonic examination of selected areas of the primary tank, coupled with a leak-detection system capable of detecting small leaks through the wall of the primary tank. The NDE program is modelled after ASME Section XI in many respects, particularly with respects to the sampling protocol. Selected testing of concrete is planned to determine if there has been any significant degradation. The most probable failure mechanisms are corrosion-related so that the examination program gives major emphasis to possible locations for corrosion attack.

  4. Multipurpose optimization models for high level waste vitrification

    SciTech Connect

    Hoza, M.

    1994-08-01

    Optimal Waste Loading (OWL) models have been developed as multipurpose tools for high-level waste studies for the Tank Waste Remediation Program at Hanford. Using nonlinear programming techniques, these models maximize the waste loading of the vitrified waste and optimize the glass formers composition such that the glass produced has the appropriate properties within the melter, and the resultant vitrified waste form meets the requirements for disposal. The OWL model can be used for a single waste stream or for blended streams. The models can determine optimal continuous blends or optimal discrete blends of a number of different wastes. The OWL models have been used to identify the most restrictive constraints, to evaluate prospective waste pretreatment methods, to formulate and evaluate blending strategies, and to determine the impacts of variability in the wastes. The OWL models will be used to aid in the design of frits and the maximize the waste in the glass for High-Level Waste (HLW) vitrification.

  5. Life Extension of Aging High-Level Waste Tanks

    SciTech Connect

    Bryson, D.; Callahan, V.; Ostrom, M.; Bryan, W.; Berman, H.

    2002-02-26

    The Double Shell Tanks (DSTs) play a critical role in the Hanford High-Level Waste Treatment Complex, and therefore activities are underway to protect and better understand these tanks. The DST Life Extension Program is focused on both tank life extension and on evaluation of tank integrity. Tank life extension activities focus on understanding tank failure modes and have produced key chemistry and operations controls to minimize tank corrosion and extend useful tank life. Tank integrity program activities have developed and applied key technologies to evaluate the condition of the tank structure and predict useful tank life. Program results to date indicate that DST useful life can be extended well beyond the original design life and allow the existing tanks to fill a critical function within the Hanford High-Level Waste Treatment Complex. In addition the tank life may now be more reliably predicted, facilitating improved planning for the use and possible future replacement of these tanks.

  6. Evaluation and selection of candidate high-level waste forms

    SciTech Connect

    Bernadzikowski, T. A.; Allender, J. S.; Butler, J. L.; Gordon, D. E.; Gould, Jr., T. H.; Stone, J. A.

    1982-03-01

    Seven candidate waste forms being developed under the direction of the Department of Energy's National High-Level Waste (HLW) Technology Program, were evaluated as potential media for the immobilization and geologic disposal of high-level nuclear wastes. The evaluation combined preliminary waste form evaluations conducted at DOE defense waste-sites and independent laboratories, peer review assessments, a product performance evaluation, and a processability analysis. Based on the combined results of these four inputs, two of the seven forms, borosilicate glass and a titanate based ceramic, SYNROC, were selected as the reference and alternative forms for continued development and evaluation in the National HLW Program. Both the glass and ceramic forms are viable candidates for use at each of the DOE defense waste-sites; they are also potential candidates for immobilization of commercial reprocessing wastes. This report describes the waste form screening process, and discusses each of the four major inputs considered in the selection of the two forms.

  7. High Level Information Fusion (HLIF) with nested fusion loops

    NASA Astrophysics Data System (ADS)

    Woodley, Robert; Gosnell, Michael; Fischer, Amber

    2013-05-01

    Situation modeling and threat prediction require higher levels of data fusion in order to provide actionable information. Beyond the sensor data and sources the analyst has access to, the use of out-sourced and re-sourced data is becoming common. Through the years, some common frameworks have emerged for dealing with information fusion—perhaps the most ubiquitous being the JDL Data Fusion Group and their initial 4-level data fusion model. Since these initial developments, numerous models of information fusion have emerged, hoping to better capture the human-centric process of data analyses within a machine-centric framework. 21st Century Systems, Inc. has developed Fusion with Uncertainty Reasoning using Nested Assessment Characterizer Elements (FURNACE) to address challenges of high level information fusion and handle bias, ambiguity, and uncertainty (BAU) for Situation Modeling, Threat Modeling, and Threat Prediction. It combines JDL fusion levels with nested fusion loops and state-of-the-art data reasoning. Initial research has shown that FURNACE is able to reduce BAU and improve the fusion process by allowing high level information fusion (HLIF) to affect lower levels without the double counting of information or other biasing issues. The initial FURNACE project was focused on the underlying algorithms to produce a fusion system able to handle BAU and repurposed data in a cohesive manner. FURNACE supports analyst's efforts to develop situation models, threat models, and threat predictions to increase situational awareness of the battlespace. FURNACE will not only revolutionize the military intelligence realm, but also benefit the larger homeland defense, law enforcement, and business intelligence markets.

  8. Third-order development of shape, gravity, and moment of inertia for highly flattened celestial bodies. Application to Ceres

    NASA Astrophysics Data System (ADS)

    Rambaux, N.; Chambat, F.; Castillo-Rogez, J. C.

    2015-12-01

    Context. We investigate the hydrostatic shape and gravitational potential coefficients of self-gravitating and rotating bodies large enough to have undergone internal differentiation and chemical stratification. Quantifying these properties under the assumption of hydrostatic equilibrium forms the basis for interpreting shape and gravity data in terms of interior structure and infer deviations from hydrostaticity that can bring information on the thermal and chemical history of the objects. Aims: The main purpose is to show the importance of developing the reference hydrostatic shape for relatively fast rotating bodies up to third order to reach an accuracy of a few tens of meters. This paper especially focuses on Ceres, for which high-resolution shape data are being obtained by the Dawn spacecraft, with a projected accuracy better than 200 m/pixel. Methods: To improve the accuracy on the determination of geodetic parameters, we numerically integrated Clairaut's equations of rotational equilibrium expanded up to third order in a small parameter m, the geodetic parameter. Results: Previous studies of Ceres have been based on shape models developed to first order. However, we show that the first-order theory underestimates (a-c) (where a and c are the equatorial and polar radii) by 1.8 km, which leads to underestimating the extent of mass concentration and is insufficient to interpret the upcoming observations by Dawn space mission. Instead, by using the third-order theory, we obtain an accuracy of 25 meters that is better than the accuracy expected from Dawn. Then, we derive the following geodetical quantities: flattening and other shape parameters, gravitational potential coefficients, and moments of inertia, by using the Ceres models constrained by observations obtained with the Hubble Space Telescope and ground-based adaptive optics telescopes. The difference in equatorial and polar radii for a large parametric space of interior models is investigated, and the large (a-c) corresponds to a model with a low density contrast. Conclusions: This type of modeling will also prove instrumental to infer non-hydrostatic contributions to Ceres' shape that are to be measured by Dawn.

  9. FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL

    SciTech Connect

    Williams, M

    2008-05-09

    Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form.

  10. Cosmological tests of gravity

    SciTech Connect

    Jain, Bhuvnesh; Khoury, Justin

    2010-07-15

    Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the universe. We review recent developments in modified gravity theories, focusing on higher-dimensional approaches and chameleon/f(R) theories. We classify these models in terms of the screening mechanisms that enable such theories to approach general relativity on small scales (and thus satisfy solar system constraints). We describe general features of the modified Friedman equation in such theories. The second half of this review describes experimental tests of gravity in light of the new theoretical approaches. We summarize the high precision tests of gravity on laboratory and solar system scales. We describe in some detail tests on astrophysical scales ranging from {approx} kpc (galaxy scales) to {approx} Gpc (large-scale structure). These tests rely on the growth and inter-relationship of perturbations in the metric potentials, density and velocity fields which can be measured using gravitational lensing, galaxy cluster abundances, galaxy clustering and the integrated Sachs-Wolfe effect. A robust way to interpret observations is by constraining effective parameters, such as the ratio of the two metric potentials. Currently tests of gravity on astrophysical scales are in the early stages - we summarize these tests and discuss the interesting prospects for new tests in the coming decade.

  11. Local acceptance of a high-level nuclear waste repository.

    PubMed

    Sjberg, Lennart

    2004-06-01

    The siting of nuclear waste facilities has been very difficult in all countries. Recent experience in Sweden indicates, however, that it may be possible, under certain circumstances, to gain local support for the siting of a high-level nuclear waste (HLNW) repository. The article reports on a study of attitudes and risk perceptions of people living in four municipalities in Sweden where HLNW siting was being intensely discussed at the political level, in media, and among the public. Data showed a relatively high level of consensus on acceptability of at least further investigation of the issue; in two cases local councils have since voted in favor of a go-ahead, and in one case only a very small majority defeated the issue. Models of policy attitudes showed that these were related to attitude to nuclear power, attributes of the perceived HLNW risk, and trust. Factors responsible for acceptance are discussed at several levels. One is the attitude to nuclear power, which is becoming more positive, probably because no viable alternatives are in sight. Other factors have to do with the extensive information programs conducted in these municipalities, and with the logical nature of the conclusion that they would be good candidates for hosting the national HLNW repository. PMID:15209942

  12. Mixing Processes in High-Level Waste Tanks - Final Report

    SciTech Connect

    Peterson, P.F.

    1999-05-24

    The mixing processes in large, complex enclosures using one-dimensional differential equations, with transport in free and wall jets is modeled using standard integral techniques. With this goal in mind, we have constructed a simple, computationally efficient numerical tool, the Berkeley Mechanistic Mixing Model, which can be used to predict the transient evolution of fuel and oxygen concentrations in DOE high-level waste tanks following loss of ventilation, and validate the model against a series of experiments.

  13. [Corrosion testing of high level radioactive waste. Final report

    SciTech Connect

    1996-06-01

    Alloys under consideration as candidates for the high level nuclear waste containers at Yucca Mountain were exposed to a range of corrosion conditions and their performance measured. The alloys tested were Incoloy 825, 70/30 Copper-Nickel, Monel 400, Hastelloy C- 22, and low carbon steel. The test conditions varied were: temperature, concentration, agitation, and crevice simulation. Only in the case of carbon steel was significant attack noted. This attack appeared to be transport limited.

  14. Automatic rule generation for high-level vision

    NASA Technical Reports Server (NTRS)

    Rhee, Frank Chung-Hoon; Krishnapuram, Raghu

    1992-01-01

    Many high-level vision systems use rule-based approaches to solving problems such as autonomous navigation and image understanding. The rules are usually elaborated by experts. However, this procedure may be rather tedious. In this paper, we propose a method to generate such rules automatically from training data. The proposed method is also capable of filtering out irrelevant features and criteria from the rules.

  15. Case for retrievable high-level nuclear waste disposal

    USGS Publications Warehouse

    Roseboom, Eugene H., Jr.

    1994-01-01

    Plans for the nation's first high-level nuclear waste repository have called for permanently closing and sealing the repository soon after it is filled. However, the hydrologic environment of the proposed site at Yucca Mountain, Nevada, should allow the repository to be kept open and the waste retrievable indefinitely. This would allow direct monitoring of the repository and maintain the options for future generations to improve upon the disposal methods or use the uranium in the spent fuel as an energy resource.

  16. Quantitative interpretation of airborne gravity gradiometry data for mineral exploration

    NASA Astrophysics Data System (ADS)

    Martinez, Cericia D.

    In the past two decades, commercialization of previously classified instrumentation has provided the ability to rapidly collect quality gravity gradient measurements for resource exploration. In the near future, next-generation instrumentation are expected to further advance acquisition of higher-quality data not subject to pre-processing regulations. Conversely, the ability to process and interpret gravity gradiometry data has not kept pace with innovations occurring in data acquisition systems. The purpose of the research presented in this thesis is to contribute to the understanding, development, and application of processing and interpretation techniques available for airborne gravity gradiometry in resource exploration. In particular, this research focuses on the utility of 3D inversion of gravity gradiometry for interpretation purposes. Towards this goal, I investigate the requisite components for an integrated interpretation workflow. In addition to practical 3D inversions, components of the workflow include estimation of density for terrain correction, processing of multi-component data using equivalent source for denoising, quantification of noise level, and component conversion. The objective is to produce high quality density distributions for subsequent geological interpretation. I then investigate the use of the inverted density model in orebody imaging, lithology differentiation, and resource evaluation. The systematic and sequential approach highlighted in the thesis addresses some of the challenges facing the use of gravity gradiometry as an exploration tool, while elucidating a procedure for incorporating gravity gradient interpretations into the lifecycle of not only resource exploration, but also resource modeling.

  17. TESTING ALTERNATIVE THEORIES OF GRAVITY USING THE SUN

    SciTech Connect

    Casanellas, Jordi; Pani, Paolo; Lopes, Ilidio; Cardoso, Vitor E-mail: paolo.pani@ist.utl.pt E-mail: vitor.cardoso@ist.utl.pt

    2012-01-20

    We propose a new approach to test possible corrections to Newtonian gravity using solar physics. The high accuracy of current solar models and new precise observations allow us to constrain corrections to standard gravity at unprecedented levels. Our case study is Eddington-inspired gravity, an attractive modified theory of gravity which results in non-singular cosmology and collapse. The theory is equivalent to standard gravity in vacuum, but it sensibly differs from it within matter. For instance, it affects the evolution and the equilibrium structure of the Sun, giving different core temperature profiles, and deviations in the observed acoustic modes and in solar neutrino fluxes. Comparing the predictions from a modified solar model with observations, we constrain the coupling parameter of the theory, |{kappa}{sub g}| {approx}< 3 Multiplication-Sign 10{sup 5} m{sup 5} s{sup -2} kg{sup -1}. Our results show that the Sun can be used to efficiently constrain alternative theories of gravity.

  18. Executive functions in kindergarteners with high levels of disruptive behaviours.

    PubMed

    Monette, Sbastien; Bigras, Marc; Guay, Marie-Claude

    2015-11-01

    Executive function (EF) deficits have yet to be demonstrated convincingly in children with disruptive behaviour disorders (DBD), as only a few studies have reported these. The presence of EF weaknesses in children with DBD has often been contested on account of the high comorbidity between DBD and attention-deficit/hyperactivity disorder (ADHD) and of methodological shortcomings regarding EF measures. Against this background, the link between EF and disruptive behaviours in kindergarteners was investigated using a carefully selected battery of EF measures. Three groups of kindergarteners were compared: (1) a group combining high levels of disruptive behaviours and ADHD symptoms (COMB); (2) a group presenting high levels of disruptive/aggressive behaviours and low levels of ADHD symptoms (AGG); and (3) a normative group (NOR). Children in the COMB and AGG groups presented weaker inhibition capacities compared with normative peers. Also, only the COMB group showed weaker working memory capacities compared with the NOR group. Results support the idea that preschool children with DBD have weaker inhibition capacities and that this weakness could be common to both ADHD and DBD. PMID:26198079

  19. Materials Science of High-Level Nuclear Waste Immobilization

    SciTech Connect

    Weber, William J.; Navrotsky, Alexandra; Stefanovsky, S. V.; Vance, E. R.; Vernaz, Etienne Y.

    2009-01-09

    With the increasing demand for the development of more nuclear power comes the responsibility to address the technical challenges of immobilizing high-level nuclear wastes in stable solid forms for interim storage or disposition in geologic repositories. The immobilization of high-level nuclear wastes has been an active area of research and development for over 50 years. Borosilicate glasses and complex ceramic composites have been developed to meet many technical challenges and current needs, although regulatory issues, which vary widely from country to country, have yet to be resolved. Cooperative international programs to develop advanced proliferation-resistant nuclear technologies to close the nuclear fuel cycle and increase the efficiency of nuclear energy production might create new separation waste streams that could demand new concepts and materials for nuclear waste immobilization. This article reviews the current state-of-the-art understanding regarding the materials science of glasses and ceramics for the immobilization of high-level nuclear waste and excess nuclear materials and discusses approaches to address new waste streams.

  20. Handbook of high-level radioactive waste transportation

    SciTech Connect

    Sattler, L.R.

    1992-10-01

    The High-Level Radioactive Waste Transportation Handbook serves as a reference to which state officials and members of the general public may turn for information on radioactive waste transportation and on the federal government`s system for transporting this waste under the Civilian Radioactive Waste Management Program. The Handbook condenses and updates information contained in the Midwestern High-Level Radioactive Waste Transportation Primer. It is intended primarily to assist legislators who, in the future, may be called upon to enact legislation pertaining to the transportation of radioactive waste through their jurisdictions. The Handbook is divided into two sections. The first section places the federal government`s program for transporting radioactive waste in context. It provides background information on nuclear waste production in the United States and traces the emergence of federal policy for disposing of radioactive waste. The second section covers the history of radioactive waste transportation; summarizes major pieces of legislation pertaining to the transportation of radioactive waste; and provides an overview of the radioactive waste transportation program developed by the US Department of Energy (DOE). To supplement this information, a summary of pertinent federal and state legislation and a glossary of terms are included as appendices, as is a list of publications produced by the Midwestern Office of The Council of State Governments (CSG-MW) as part of the Midwestern High-Level Radioactive Waste Transportation Project.

  1. [Kinetic theory and boundary conditions for flows of highly inelastic spheres: Application to gravity driven granular flows down bumpy inclines

    SciTech Connect

    Richman, M.W.

    1992-01-01

    In this quarter, we extended our study of the effects of isotropic boundary vibrations to steady, gravity driven, inclined granular flows. These flows are more complex than those considered last quarter because of the presence of slip and mean velocity gradients at the boundary. Consequently, it was first necessary to modify the boundary conditions derived by Richman (1992) to account for corrections to the flow particle velocity distribution function from velocity gradients. In what follows we only summarize the results obtained.

  2. High Levels of Molecular Chlorine found in the Arctic Atmosphere

    NASA Astrophysics Data System (ADS)

    Liao, J.; Huey, L. G.; Liu, Z.; Tanner, D.; Cantrell, C. A.; Orlando, J. J.; Flocke, F. M.; Shepson, P. B.; Weinheimer, A. J.; Hall, S. R.; Beine, H.; Wang, Y.; Ingall, E. D.; Thompson, C. R.; Hornbrook, R. S.; Apel, E. C.; Fried, A.; Mauldin, L.; Smith, J. N.; Staebler, R. M.; Neuman, J. A.; Nowak, J. B.

    2014-12-01

    Chlorine radicals are a strong atmospheric oxidant, particularly in polar regions where levels of hydroxyl radicals can be quite low. In the atmosphere, chlorine radicals expedite the degradation of methane and tropospheric ozone and the oxidation of mercury to more toxic forms. Here, we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We detected high levels of molecular chlorine of up to 400 pptv. Concentrations peaked in the early morning and late afternoon and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimated that the chlorine radicals produced from the photolysis of molecular chlorine on average oxidized more methane than hydroxyl radicals and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyzed mercury oxidation and the breakdown of tropospheric ozone. Therefore, we propose that molecular chlorine exerts a significant effect on the atmospheric chemistry in the Arctic. While the formation mechanisms of molecular chlorine are not yet understood, the main potential sources of chlorine include snowpack, sea salt, and sea ice. There is recent evidence of molecular halogen (Br2 and Cl2) formation in the Arctic snowpack. The coverage and composition of the snow may control halogen chemistry in the Arctic. Changes of sea ice and snow cover in the changing climate may affect air-snow-ice interaction and have a significant impact on the levels of radicals, ozone, mercury and methane in the Arctic troposphere.

  3. Improved GRACE preprocessing methodologies: impact on monthly gravity field solutions

    NASA Astrophysics Data System (ADS)

    Klinger, Beate; Mayer-Guerr, Torsten

    2015-04-01

    The GRACE (Gravity Recovery and Climate Experiment) satellite mission provides K-band ranging (KBR) measurements between the two twin satellites GRACE-A and GRACE-B for the purpose of gravity field recovery. Although the accuracy of gravity field solutions has evolved considerably during the last years, there still remains an offset between the present error level and the predicted GRACE baseline accuracy. Efforts are made to identify the remaining error sources. Both unmodeled errors within the Level-1B data products related to the alignment and outliers within the GRACE observations are potential contributors to the error budget. As the precise inter-satellite pointing is one of the essential requirements for the KBR ranging, we combine both angular accelerometer and star camera data (ACC1B, SCA1B) in a least squares approach to improve the satellites' attitude determination. As a result, the high frequent noise of the attitude data is decreased significantly. In order to benefit from the improvements on the sensor data level, other error sources and disturbances within the GRACE observations have to be identified. Based on these results, we show that even after more than 12 years of mission operation, improved modeling and preprocessing methodologies (e.g.: sensor fusion, outlier detection within the ACC1B data) contribute substantially to the overall accuracy of the recovered monthly gravity field solutions. The purpose of the presented work is to understand and reduce the impact of possible error sources on the GRACE gravity field recovery.

  4. Investigating Propagation of Short-period Gravity Waves at High Altitudes Utilizing Re-analysis and Ray Tracing Models

    NASA Astrophysics Data System (ADS)

    Nielsen, K.; Pautet, P.; Taylor, M. J.; Broutman, D.; Collins, R. L.; Irving, B.; Negale, M.; Siskind, D. E.; Eckermann, S. D.; Hoppel, K.; Martin, T.; Harvey, V.

    2012-12-01

    Short-period gravity waves exhibiting periods <1 hour are of great interest as these waves propagate near vertically and transport large amount of momentum flux into the mesosphere and lower thermosphere (MLT) region. They have preponderance for propagation against the background flow and, when breaking and depositing the momentum flux decrease or even reverse this flow. The propagation nature and sources of short-period mesospheric gravity waves have been studied extensively at low and mid-latitudes, while their extent and nature at the Polar Regions are less known. During the last decade, observations from select sites on the Antarctic continent have revealed a significant presence of short-period gravity waves over the southern Polar Region as well as shown unexpected dynamical behavior. A most recent study from Halley, Antarctica, have shown the majority of the waves to be vertically propagating in the MLT region, which is in stark contrast to similar studies at mid-latitudes, where the waves are prone to ducted motion. In this presentation, we elaborate on the propagation characteristics throughout the middle atmosphere of waves observed over the Polar Regions by using global scale reanalysis and ray tracing models.

  5. Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory

    SciTech Connect

    Chan, H.A.; Paik, H.J.

    1987-06-15

    Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with very high sensitivity and stability. A superconducting gravity gradiometer has been developed for a null test of the gravitational inverse-square law and space-borne geodesy. Here we present a complete theoretical model of this instrument. Starting from dynamical equations for the device, we derive transfer functions, a common mode rejection characteristic, and an error model of the superconducting instrument. Since a gradiometer must detect a very weak differential gravity signal in the midst of large platform accelerations and other environmental disturbances, the scale factor and common mode rejection stability of the instrument are extremely important in addition to its immunity to temperature and electromagnetic fluctuations. We show how flux quantization, the Meissner effect, and properties of liquid helium can be utilized to meet these challenges.

  6. Validation of GOCE gravity gradient grids for geophysical applications

    NASA Astrophysics Data System (ADS)

    Fecher, Thomas; Pail, Roland; Rexer, Moritz

    2015-04-01

    In addition to global gravity models parameterized in spherical harmonic coefficients, gravity functionals such as gravity gradients, as they have been measured by the GOCE satellite, are an important data product for many user groups. Exemplarily, in geophysical modelling, the directional information contained in the gravity gradients can further constrain the inversion problem. Global and regional gravity gradient grids have been computed in the frame of the ESA STSE GOCE+ project GeoExplore in a local north-oriented frame in two altitudes of 225 km and 255 km, basically as a combination of GOCE and GRACE information in a regional combination approach. In parallel, in the frame of the project GOCE High-level Processing Facility (HPF) global grids based purely on GOCE information have been produced by applying the space-wise approach. Following a recommendation of the ESA GOCE User Workshop (Paris, November 2014), these grids have to be validated externally before they can be reliably used for geophysical applications. In this paper, these grid products are validated against external gravity information, by applying global gravity field models and terrestrial data bases in well-surveyed areas. By comparing the gravity gradient grid products against reference values computed from the global satellite-only model GOCO05S (both the official as well as an unregularized version of it), it shall be evaluated if systematic effects show up, which might be related to the specific features of the combination strategy. The differences shall be analysed applying statistical test methods, and the error estimates associated with the grid products shall be evaluated. In parallel, it shall be investigated whether the gravity gradient grid product indeed contains more (high-frequency) signals than global models. This shall further be elaborated on by a validation against a combined gravity field model, which also includes terrestrial gravity and satellite altimetry data, as well as against terrestrial data in well-surveyed areas. In this presentation, the validation method shall be briefly outlined, the evaluation results for the recent global and regional grid products that are available shall be discussed, and a recommendation for the optimum use of these products shall be derived.

  7. Preliminary results of gravity investigations at Yucca Mountain and vicinity, Southern Nye County, Nevada

    SciTech Connect

    Snyder, D.B.; Carr, W.J.

    1982-12-31

    Exploration for a high-level-nuclear-waste-repository site in the Yucca Mountain area, Nevada, resulted in the addition of 423 new gravity stations during the past 2 years to the 934 existing stations to form the data base of this study. About 100 surface-rock samples, three borehole gamma-gamma logs, and one borehole gravity study provide excellent density control. A linear increase in density of 0.26 g/cm{sup 3} per km is indicated in the tuff sequences makes the density contrast across the basal contact of the tuff the only strong source of gravity fluctuations. Isostatic and 2.0g/cm{sup 3} Bouguer corrections were applied to the observed gravity values to remove deep-crust-related regional gradients and topographic effects, respectively. The resulting residual-gravity plot shows significant gravity anomalies that correlate closely with the structures inferred from drill-hole and surface geologic studies. Gravity highs over the three Paleozoic rock outcrops within the study area - Bare Mountain, the Calico Hills, and the Striped Hills - served as reference points for the gravity models. At least 3000 m of tuff fills a large steep-sided depression in the prevolcanic rocks beneath Yucca Mountain and Crater Flat. The gravity low and thick tuff section probably lie within a large collapse area comprising the Crater Flat-Timber Mountain-Silent Canyon caldera complexes. Gravity lows in Crater Flat itself are thought to coincide with the source areas of the Prow Pass Member, the Bullfrog Member, and the unnamed member of the Crater Flat Tuff. Southward extension of the broad gravity low associated with Crater Flat into the Amargosa Desert is evidence for sector graben-type collapse segments related to the Timber Mountain caldera and superimposed on the other structures within Crater Flat. 13 figures, 4 tables.

  8. High illness loads (physical and social) do not always force high levels of mass religiosity.

    PubMed

    Paul, Gregory S

    2012-04-01

    The hypothesis that high levels of religiosity are partly caused by high disease loads is in accord with studies showing that societal dysfunction promotes mass supernaturalism. However, some cultures suffering from high rates of disease and other socioeconomic dysfunction exhibit low levels of popular religiosity. At this point, it appears that religion is hard pressed to thrive in healthy societies, but poor conditions do not always make religion popular, either. PMID:22289444

  9. Antarctic outlet glacier mass change resolved at basin scale from satellite gravity gradiometry

    NASA Astrophysics Data System (ADS)

    Bouman, J.; Fuchs, M.; Ivins, E.; Wal, W.; Schrama, E.; Visser, P.; Horwath, M.

    2014-08-01

    The orbit and instrumental measurement of the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) satellite mission offer the highest ever resolution capabilities for mapping Earth's gravity field from space. However, past analysis predicted that GOCE would not detect changes in ice sheet mass. Here we demonstrate that GOCE gravity gradiometry observations can be combined with Gravity Recovery and Climate Experiment (GRACE) gravity data to estimate mass changes in the Amundsen Sea Sector. This refined resolution allows land ice changes within the Pine Island Glacier (PIG), Thwaites Glacier, and Getz Ice Shelf drainage systems to be measured at respectively -67 ± 7, -63 ± 12, and -55 ± 9 Gt/yr over the GOCE observing period of November 2009 to June 2012. This is the most accurate pure satellite gravimetry measurement to date of current mass loss from PIG, known as the "weak underbelly" of West Antarctica because of its retrograde bed slope and high potential for raising future sea level.

  10. A note on classical and quantum unimodular gravity

    NASA Astrophysics Data System (ADS)

    Padilla, Antonio; Saltas, Ippocratis D.

    2015-11-01

    We discuss unimodular gravity at a classical level, and in terms of its extension into the UV through an appropriate path integral representation. Classically, unimodular gravity is locally a gauge fixed version of general relativity (GR), and as such it yields identical dynamics and physical predictions. We clarify this and explain why there is no sense in which it can "bring a new perspective" to the cosmological constant problem. The quantum equivalence between unimodular gravity and GR is more of a subtle question, but we present an argument that suggests one can always maintain the equivalence up to arbitrarily high momenta. As a corollary to this, we argue, whenever inequivalence is seen at the quantum level, that just means we have defined two different quantum theories that happen to share a classical limit. We also present a number of alternative formulations for a covariant unimodular action, some of which have not appeared, to our knowledge, in the literature before.

  11. Radiative Lifetimes for High Levels of Neutral Fe

    NASA Astrophysics Data System (ADS)

    Lawler, James E.; Den Hartog, E.; Guzman, A.

    2013-01-01

    New radiative lifetime measurements for ~ 50 high lying levels of Fe I are reported. Laboratory astrophysics faces a challenge to provide basic spectroscopic data, especially reliable atomic transition probabilities, in the IR region for abundance studies. The availability of HgCdTe (HAWAII) detector arrays has opened IR spectral regions for extensive new spectroscopic studies. The SDSS III APOGEE project in the H-Band is an important example which will penetrate the dust obscuring the Galactic bulge. APOGEE will survey elemental abundances of 100,000 red giant stars in the bulge, bar, disk, and halo of the Milky Way. Many stellar spectra in the H-Band are, as expected, dominated by transitions of Fe I. Most of these IR transitions connect high levels of Fe. Our program has started an effort to meet this challenge with new radiative lifetime measurements on high lying levels of Fe I using time resolved laser induced fluorescence (TRLIF). The TRLIF method is typically accurate to 5% and is efficient. Our goal is to combine these accurate, absolute radiative lifetimes with emission branching fractions [1] to determine log(gf) values of the highest quality for Fe I lines in the UV, visible, and IR. This method was used very successfully by O’Brian et al. [2] on lower levels of Fe I. This method is still the best available for all but very simple spectra for which ab-initio theory is more accurate. Supported by NSF grant AST-0907732. [1] Branching fractions are being measured by M. Ruffoni and J. C. Pickering at Imperial College London. [2] O'Brian, T. R., Wickliffe, M. E., Lawler, J. E., Whaling, W., & Brault, J. W. 1991, J. Opt. Soc. Am. B 8, 1185

  12. ALICE: Project Overview and High Level Science Products

    NASA Astrophysics Data System (ADS)

    Soummer, Remi; Choquet, Elodie; Pueyo, Laurent; Brendan Hagan, J.; Gofas-Salas, Elena; Rajan, Abhijith; Perrin, Marshall D.; Chen, Christine; Debes, John H.; Golimowski, David A.; Hines, Dean C.; Schneider, Glenn; N'Diaye, Mamadou; Mawet, Dimitri; Marois, Christian; Barman, Travis

    2015-01-01

    We report on the status of the ALICE project (Archival Legacy Investigation of Circumstellar Environments), which consists in a consistent reanalysis of the entire HST-NICMOS coronagraphic archive. Over the last two years, we have developed a sophisticated pipeline able to handle the data of the 400 stars of the archive. This pipeline builds on the Karhunen-Loeve Image Projection (KLIP) algorithm, and was completed in the fall of 2014. We discuss the first processing and analysis results of the overall reduction campaign. As we will deliver high-level science products to the STScI MAST archive, we are defining a new standard format for high-contrast science products, which will be compatible with every new high-contrast imaging instrument (GPI, SPHERE, P1640, CHARIS, etc.) and used by the JWST coronagraphs. We present here the specifications of this standard.

  13. High level language-based robotic control system

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo (Inventor); Kreutz, Kenneth K. (Inventor); Jain, Abhinandan (Inventor)

    1996-01-01

    This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages.

  14. High level language-based robotic control system

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo (Inventor); Kruetz, Kenneth K. (Inventor); Jain, Abhinandan (Inventor)

    1994-01-01

    This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages.

  15. Space augmentation of military high-level waste disposal

    NASA Technical Reports Server (NTRS)

    English, T.; Lees, L.; Divita, E.

    1979-01-01

    Space disposal of selected components of military high-level waste (HLW) is considered. This disposal option offers the promise of eliminating the long-lived radionuclides in military HLW from the earth. A space mission which meets the dual requirements of long-term orbital stability and a maximum of one space shuttle launch per week over a period of 20-40 years, is a heliocentric orbit about halfway between the orbits of earth and Venus. Space disposal of high-level radioactive waste is characterized by long-term predictability and short-term uncertainties which must be reduced to acceptably low levels. For example, failure of either the Orbit Transfer Vehicle after leaving low earth orbit, or the storable propellant stage failure at perihelion would leave the nuclear waste package in an unplanned and potentially unstable orbit. Since potential earth reencounter and subsequent burn-up in the earth's atmosphere is unacceptable, a deep space rendezvous, docking, and retrieval capability must be developed.

  16. Permitting plan for the high-level waste interim storage

    SciTech Connect

    Deffenbaugh, M.L.

    1997-04-23

    This document addresses the environmental permitting requirements for the transportation and interim storage of solidified high-level waste (HLW) produced during Phase 1 of the Hanford Site privatization effort. Solidified HLW consists of canisters containing vitrified HLW (glass) and containers that hold cesium separated during low-level waste pretreatment. The glass canisters and cesium containers will be transported to the Canister Storage Building (CSB) in a U.S. Department of Energy (DOE)-provided transportation cask via diesel-powered tractor trailer. Tri-Party Agreement (TPA) Milestone M-90 establishes a new major milestone, and associated interim milestones and target dates, governing acquisition and/or modification of facilities necessary for: (1) interim storage of Tank Waste Remediation Systems (TWRS) immobilized HLW (IHLW) and other canistered high-level waste forms; and (2) interim storage and disposal of TWRS immobilized low-activity tank waste (ILAW). An environmental requirements checklist and narrative was developed to identify the permitting path forward for the HLW interim storage (HLWIS) project (See Appendix B). This permitting plan will follow the permitting logic developed in that checklist.

  17. Characterization of Transducers and Resonators under High Drive Levels

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Bao, X.; Sigel, D. A.; Gradziel, M. J.; Askins, S. A.; Dolgin, B. P.; Bar-Cohen, Y.

    2001-01-01

    In many applications, piezoelectric transducers are driven at AC voltage levels well beyond the level for which the material was nominally characterized. In this paper we describe an experimental setup that allows for the determination of the main transducer or resonator properties under large AC drive. A sinusoidal voltage from a waveform generator is amplified and applied across the transducer/resonator in series with a known high power resistor. The amplitude of applied voltage and the amplitude and the relative phase of the current through the resistor are monitored on a digital scope. The frequency of the applied signal is swept through resonance and the voltage/current signals are recorded. After corrections for the series resistance and parasitic elements the technique allows for the determination of the complex impedance spectra of the sample as a function of frequency. In addition, access to the current signal allows for the direct investigation of non-linear effects through the application of Fourier transform techniques on the current signal. Our results indicate that care is required when interpreting impedance data at high drive level due to the frequency dependence of the dissipated power. Although the transducer/resonator at a single frequency and after many cycles may reach thermal equilibrium, the spectra as a whole cannot be considered an isothermal measurement due to the temperature change with frequency. Methods to correct for this effect will be discussed. Results determined from resonators of both soft and hard PZT and a ultrasonic horn transducer are presented.

  18. Gravity change observed in a local gravity network and its implication to seasonal precipitation in Dali county, Yunnan province, China

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; Sun, Wenke; Li, Hui; Okubo, Shuhei; Sun, Shaoan; Xing, Lelin; Liu, Dongzhi; Shen, Chongyang

    2014-02-01

    This study investigates data-processing methods and examines the precipitation effect on gravity measurements at the Dali gravity network, established in 2005. High-quality gravity data were collected during four measurement campaigns. To use the gravity data validly, some geophysical corrections must be considered carefully. We first discuss data-processing methods using weighted least-squares adjustment with the constraint of the absolute gravity datum. Results indicate that the gravity precision can be improved if all absolute gravity data are used as constraints and if calibration functions of relative gravimeters are modeled within the observation function. Using this data-processing scheme, the mean point gravity precision is better than 12 ?gal. After determining the best data-processing scheme, we then process the gravity data obtained in the four measurement campaigns, and obtain gravity changes in three time periods. Results show that the gravity has a remarkable change of more than 50 ?gal in the first time period from Apr-May of 2005 to Aug-Sept of 2007. To interpret the large gravity change, a mean water mass change (0.6 m in height) is assumed in the ETOPO1 topographic model. Calculations of the precipitation effect on gravity show that it can reach the same order of the observed gravity change. It is regarded as a main source of the remarkable gravity change in the Dali gravity network, suggesting that the precipitation effect on gravity measurements must be considered carefully.

  19. University-Level Research Projects for High School Students

    NASA Technical Reports Server (NTRS)

    McConnell, Mark L.

    2000-01-01

    The goal of this project was to provide an opportunity for high school students to participate in university-level research projects. In this case, students from Pinkerton Academy (Derry, New Hampshire) were invited to participate in efforts to catalog data from the COMPTEL experiment on NASA's Compton Gamma-Ray Observatory (CGRO). These activities were part of a senior level honors course at Pinkerton. Although the success of this particular program was rather limited, we feel that the general concept is a sound one. In principle, the concept of partnerships between local schools and university researchers is one that could be especially attractive to soft money researchers. Programs can be carefully designed to benefit both the students and the research program.

  20. Effects of high vs low-level radiation exposure

    SciTech Connect

    Bond, V.P.

    1983-01-01

    In order to appreciate adequately the various possible effects of radiation, particularly from high-level vs low-level radiation exposure (HLRE, vs LLRE), it is necessary to understand the substantial differences between (a) exposure as used in exposure-incidence curves, which are always initially linear and without threshold, and (b) dose as used in dose-response curves, which always have a threshold, above which the function is curvilinear with increasing slope. The differences are discussed first in terms of generally familiar nonradiation situations involving dose vs exposure, and then specifically in terms of exposure to radiation, vs a dose of radiation. Examples are given of relevant biomedical findings illustrating that, while dose can be used with HLRE, it is inappropriate and misleading the LLRE where exposure is the conceptually correct measure of the amount of radiation involved.

  1. Online testbench for LHCb High Level Trigger validation

    NASA Astrophysics Data System (ADS)

    Frank, M.; Garnier, J.; Gaspar, C.; Liu, G.; Neufeld, N.; Varela, A. S.

    2010-04-01

    The High Level Trigger (HLT) and Data Acquisition (DAQ) system selects about 2 kHz of events out of the 40 MHz of beam crossings. The selected events are consolidated into files on an onsite storage and then sent to permanent storage for subsequent analysis on the Grid. For local and full-chain tests a method to exercise the data-flow through the High Level Trigger when there are no actual data is needed. In order to test the system as much as possible under identical conditions as for data-taking the solution is to inject data at the input of the HLT at a minimum rate of 2 kHz. This is done via a software implementation of the trigger system which sends data to the HLT. The application has to simulate that the data it sends come from real LHCb readout-boards. Both simulation data and previously recorded real data can be re-played through the system in this manner. As the data rate is high (100 MB/s), care has been taken to optimise the emulator for throughput from the Storage Area Network (SAN). The emulator can be run in stand-alone mode or run as a pseudo-subdetector of LHCb, allowing for use of all the standard run-control tools. The architecture, implementation and performance of the emulator will be presented.

  2. High-level expression of Camelid nanobodies in Nicotiana benthamiana.

    PubMed

    Teh, Yi-Hui Audrey; Kavanagh, Tony A

    2010-08-01

    Nanobodies (or VHHs) are single-domain antigen-binding fragments derived from Camelid heavy chain-only antibodies. Their small size, monomeric behaviour, high stability and solubility, and ability to bind epitopes not accessible to conventional antibodies make them especially suitable for many therapeutic and biotechnological applications. Here we describe high-level expression, in Nicotiana benthamiana, of three versions of an anti-hen egg white lysozyme (HEWL) nanobody which include the original VHH from an immunized library (cAbLys3), a codon-optimized derivative, and a codon-optimized hybrid nanobody comprising the CDRs of cAbLys3 grafted onto an alternative 'universal' nanobody framework. His6- and StrepII-tagged derivatives of each nanobody were targeted for accumulation in the cytoplasm, chloroplast and apoplast using different pre-sequences. When targeted to the apoplast, intact functional nanobodies accumulated at an exceptionally high level (up to 30% total leaf protein), demonstrating the great potential of plants as a nanobody production system. PMID:19862637

  3. Engineering Escherichia coli for high-level production of propionate.

    PubMed

    Akawi, Lamees; Srirangan, Kajan; Liu, Xuejia; Moo-Young, Murray; Perry Chou, C

    2015-07-01

    Mounting environmental concerns associated with the use of petroleum-based chemical manufacturing practices has generated significant interest in the development of biological alternatives for the production of propionate. However, biological platforms for propionate production have been limited to strict anaerobes, such as Propionibacteria and select Clostridia. In this work, we demonstrated high-level heterologous production of propionate under microaerobic conditions in engineered Escherichia coli. Activation of the native Sleeping beauty mutase (Sbm) operon not only transformed E. coli to be propionogenic (i.e., propionate-producing) but also introduced an intracellular "flux competition" between the traditional C2-fermentative pathway and the novel C3-fermentative pathway. Dissimilation of the major carbon source of glycerol was identified to critically affect such "flux competition" and, therefore, propionate synthesis. As a result, the propionogenic E. coli was further engineered by inactivation or overexpression of various genes involved in the glycerol dissimilation pathways and their individual genetic effects on propionate production were investigated. Generally, knocking out genes involved in glycerol dissimilation (except glpA) can minimize levels of solventogenesis and shift more dissimilated carbon flux toward the C3-fermentative pathway. For optimal propionate production with high C3:C2-fermentative product ratios, glycerol dissimilation should be channeled through the respiratory pathway and, upon suppressed solventogenesis with minimal production of highly reduced alcohols, the alternative NADH-consuming route associated with propionate synthesis can be critical for more flexible redox balancing. With the implementation of various biochemical and genetic strategies, high propionate titers of more than 11g/L with high yields up to 0.4g-propionate/g-glycerol (accounting for ~50% of dissimilated glycerol) were achieved, demonstrating the potential for industrial application. To our knowledge, this represents the most effective engineered microbial system for propionate production with titers and yields comparable to those achieved by anaerobic batch cultivation of various native propionate-producing strains of Propionibacteria. PMID:25948049

  4. Identifying high-level features of texture perception

    NASA Astrophysics Data System (ADS)

    Rao, A. Ravishankar; Lohse, Gerald L.

    1992-08-01

    A fundamental issue in texture analysis is that of deciding what textural features are important in texture perception, and how they are used. Experiments on human pre-attentive vision have identified several low-level features (such as orientation on blobs, and size of line segments), which are used in texture perception. However, the question of what higher level features of texture are used has not been adequately addressed. We designed an experiment to help identify the relevant higher order features of texture perceived by humans. We used twenty subjects, who were asked to perform an unsupervised classification of thirty pictures from Brodatz's album on texture. Each subject was asked to group these pictures into as many classes as desired. Both hierarchical cluster analysis and non-metric MDS were applied to the pooled similarity matrix generated from the subjects' groupings. A surprising outcome is that the MDS solutions fit the data very well. The stress in the two dimensional case is 0.10, and in the three dimensional case is 0.045. We rendered the original textures in these coordinate systems, and interpreted the (rotated) axes. It appears that the axes in the 2D case correspond to periodicity versus irregularity, and directional versus non-directional. In the 3D case, the third dimension represents the structural complexity of the texture. Furthermore, the clusters identified by the hierarchical cluster analysis remain virtually intact in the MDS solution. The results of our experiment indicate that people use three high level features for texture perception. Future studies are needed to determine the appropriateness of these high-level features for computational texture analysis and classification.

  5. Quantum gravity and charge renormalization

    SciTech Connect

    Toms, David J.

    2007-08-15

    We study the question of the gauge dependence of the quantum gravity contribution to the running gauge coupling constant for electromagnetism. The calculations are performed using dimensional regularization in a manifestly gauge-invariant and gauge-condition-independent formulation of the effective action. It is shown that there is no quantum gravity contribution to the running charge, and hence there is no alteration to asymptotic freedom at high energies as predicted by Robinson and Wilczek.

  6. Bubble Formation and Detachment in Reduced Gravity Under the Influence of Electric Fields

    NASA Technical Reports Server (NTRS)

    Herman, Cila; Iacona, Estelle; Chang, Shinan

    2002-01-01

    The objective of the study is to investigate the behavior of individual air bubbles injected through an orifice into an electrically insulating liquid under the influence of a static electric field. Both uniform and nonuniform electric field configurations were considered. Bubble formation and detachment were recorded and visualized in reduced gravity (corresponding to gravity levels on Mars, on the Moon as well as microgravity) using a high-speed video camera. Bubble volume, dimensions and contact angle at detachment were measured. In addition to the experimental studies, a simple model, predicting bubble characteristics at detachment was developed. The model, based on thermodynamic considerations, accounts for the level of gravity as well as the magnitude of the uniform electric field. Measured data and model predictions show good agreement and indicate that the level of gravity and the electric field magnitude significantly affect bubble shape, volume and dimensions.

  7. Bubble Detachment in Variable Gravity Under the Influence of Electric Fields

    NASA Technical Reports Server (NTRS)

    Herman, Cila; Chang, Shinan; Iacona, Estelle

    2002-01-01

    The objective of the research is to investigate the behavior of individual air bubbles injected through an orifice into an electrically insulating liquid under the influence of a static electric field. Situations were considered with both uniform and nonuniform electric fields. Bubble formation and detachment were visualized in terrestrial gravity as well as for several levels of reduced gravity (lunar, martian and microgravity) using a high-speed video camera. Bubble volume, dimensions and contact angles at detachment were measured. In addition to the experimental studies, a simple model, predicting bubble characteristics at detachment in an initially uniform electric field was developed. The model, based on thermodynamic considerations, accounts for the level of gravity as well as the magnitude of the uniform electric field. The results of the study indicate that the level of gravity and the electric field magnitude significantly affect bubble behavior as well as shape, volume and dimensions.

  8. Salivary Fluoride Levels after Use of High-Fluoride Dentifrice

    PubMed Central

    Vale, Glauber Campos; Cruz, Priscila Figueiredo; Bohn, Ana Clarissa Cavalcante Elvas; de Moura, Marcoeli Silva

    2015-01-01

    The aim of the study was to evaluate salivary fluoride (F) availability after toothbrushing with a high-F dentifrice. Twelve adult volunteers took part in this crossover and blind study. F concentration in saliva was determined after brushing with a high-F dentifrice (5000?g?F/g) or with a conventional F concentration dentifrice (1100?g?F/g) followed by a 15?mL distilled water rinse. Samples of nonstimulated saliva were collected on the following times: before (baseline), and immediately after spit (time = 0) and after 1, 2, 3, 4, 5, 10, 15, 20, 30, 45, 60, 90, and 120?min. F analysis was performed with a fluoride-sensitive electrode and the area under curve of F salivary concentration time (g?F/mL min?1) was calculated. At baseline, no significant difference was found among dentifrices (P > 0.05). After brushing, both dentifrices caused an elevated fluoride level in saliva; however salivary F concentration was significantly higher at all times, when high-F dentifrice was used (P < 0.01). Even after 120?min, salivary F concentration was still higher than the baseline values for both dentifrices (P < 0.001). High-F dentifrice enhanced the bioavailability of salivary F, being an option for caries management in patients with high caries risk. PMID:25821849

  9. CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315

    SciTech Connect

    Langton, C.; Burns, H.; Stefanko, D.

    2012-01-10

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. The closure will also fill, physically stabilize and isolate ancillary equipment abandoned in the tanks. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and chemically reduction potential (Eh) of -200 to -400 to stabilize selected potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted, respectively, to support the mass placement strategy developed by closure operations. Subsequent down selection was based on compressive strength and saturated hydraulic conductivity results. Fresh slurry property results were used as the first level of screening. A high range water reducing admixture and a viscosity modifying admixture were used to adjust slurry properties to achieve flowable grouts. Adiabatic calorimeter results were used as the second level screening. The third level of screening was used to design mixes that were consistent with the fill material parameters used in the F-Tank Farm Performance Assessment which was developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closures.

  10. High level secretion of cellobiohydrolases by Saccharomyces cerevisiae

    PubMed Central

    2011-01-01

    Background The main technological impediment to widespread utilization of lignocellulose for the production of fuels and chemicals is the lack of low-cost technologies to overcome its recalcitrance. Organisms that hydrolyze lignocellulose and produce a valuable product such as ethanol at a high rate and titer could significantly reduce the costs of biomass conversion technologies, and will allow separate conversion steps to be combined in a consolidated bioprocess (CBP). Development of Saccharomyces cerevisiae for CBP requires the high level secretion of cellulases, particularly cellobiohydrolases. Results We expressed various cellobiohydrolases to identify enzymes that were efficiently secreted by S. cerevisiae. For enhanced cellulose hydrolysis, we engineered bimodular derivatives of a well secreted enzyme that naturally lacks the carbohydrate-binding module, and constructed strains expressing combinations of cbh1 and cbh2 genes. Though there was significant variability in the enzyme levels produced, up to approximately 0.3 g/L CBH1 and approximately 1 g/L CBH2 could be produced in high cell density fermentations. Furthermore, we could show activation of the unfolded protein response as a result of cellobiohydrolase production. Finally, we report fermentation of microcrystalline cellulose (Avicel) to ethanol by CBH-producing S. cerevisiae strains with the addition of beta-glucosidase. Conclusions Gene or protein specific features and compatibility with the host are important for efficient cellobiohydrolase secretion in yeast. The present work demonstrated that production of both CBH1 and CBH2 could be improved to levels where the barrier to CBH sufficiency in the hydrolysis of cellulose was overcome. PMID:21910902

  11. Development of a High Level Waste Tank Inspection System

    SciTech Connect

    Appel, D.K.; Loibl, M.W.; Meese, D.C.

    1995-03-21

    The Westinghouse Savannah River Technology Center was requested by it`s sister site, West Valley Nuclear Service (WVNS), to develop a remote inspection system to gather wall thickness readings of their High Level Waste Tanks. WVNS management chose to take a proactive approach to gain current information on two tanks t hat had been in service since the early 70`s. The tanks contain high level waste, are buried underground, and have only two access ports to an annular space between the tank and the secondary concrete vault. A specialized remote system was proposed to provide both a visual surveillance and ultrasonic thickness measurements of the tank walls. A magnetic wheeled crawler was the basis for the remote delivery system integrated with an off-the-shelf Ultrasonic Data Acquisition System. A development program was initiated for Savannah River Technology Center (SRTC) to design, fabricate, and test a remote system based on the Crawler. The system was completed and involved three crawlers to perform the needed tasks, an Ultrasonic Crawler, a Camera Crawler, and a Surface Prep Crawler. The crawlers were computer controlled so that their operation could be done remotely and their position on the wall could be tracked. The Ultrasonic Crawler controls were interfaced with ABB Amdata`s I-PC, Ultrasonic Data Acquisition System so that thickness mapping of the wall could be obtained. A second system was requested by Westinghouse Savannah River Company (WSRC), to perform just ultrasonic mapping on their similar Waste Storage Tanks; however, the system needed to be interfaced with the P-scan Ultrasonic Data Acquisition System. Both remote inspection systems were completed 9/94. Qualifications tests were conducted by WVNS prior to implementation on the actual tank and tank development was achieved 10/94. The second inspection system was deployed at WSRC 11/94 with success, and the system is now in continuous service inspecting the remaining high level waste tanks at WSRC.

  12. Artificial gravity.

    PubMed

    Scott, William B

    2005-04-25

    NASA's Artificial Gravity program consists of a team of researchers from Wyle Laboratories, NASA Johnson Space Center, and the University of Texas Medical Branch (UTMB). The short-radius centrifuge (SRC), built by Wyle Laboratories, will be integrated with UTMB's conducted bedrest studies, which mimic the detrimental effects of weightlessness (or microgravity). Bedrest subjects will be spun on the SRC at various accelerations and for various time periods, while being monitored medically. Parameters such as bone loss, muscle atrophy, balance control, and oxygen consumption will then be compared in order to research ways of mitigating the impact on astronauts' physiology. Other potential benefits from these studies extend to population groups on Earth, such as bedridden patients. PMID:15852559

  13. Stagnation Region Heat Transfer Augmentation at Very High Turbulence Levels

    SciTech Connect

    Ames, Forrest; Kingery, Joseph E.

    2015-06-17

    A database for stagnation region heat transfer has been extended to include heat transfer measurements acquired downstream from a new high intensity turbulence generator. This work was motivated by gas turbine industry heat transfer designers who deal with heat transfer environments with increasing Reynolds numbers and very high turbulence levels. The new mock aero-combustor turbulence generator produces turbulence levels which average 17.4%, which is 37% higher than the older turbulence generator. The increased level of turbulence is caused by the reduced contraction ratio from the liner to the exit. Heat transfer measurements were acquired on two large cylindrical leading edge test surfaces having a four to one range in leading edge diameter (40.64 cm and 10.16 cm). Gandvarapu and Ames [1] previously acquired heat transfer measurements for six turbulence conditions including three grid conditions, two lower turbulence aero-combustor conditions, and a low turbulence condition. The data are documented and tabulated for an eight to one range in Reynolds numbers for each test surface with Reynolds numbers ranging from 62,500 to 500,000 for the large leading edge and 15,625 to 125,000 for the smaller leading edge. The data show augmentation levels of up to 136% in the stagnation region for the large leading edge. This heat transfer rate is an increase over the previous aero-combustor turbulence generator which had augmentation levels up to 110%. Note, the rate of increase in heat transfer augmentation decreases for the large cylindrical leading edge inferring only a limited level of turbulence intensification in the stagnation region. The smaller cylindrical leading edge shows more consistency with earlier stagnation region heat transfer results correlated on the TRL (Turbulence, Reynolds number, Length scale) parameter. The downstream regions of both test surfaces continue to accelerate the flow but at a much lower rate than the leading edge. Bypass transition occurs in these regions providing a useful set of data to ground the prediction of transition onset and length over a wide range of Reynolds numbers and turbulence intensity and scales.

  14. The 3-D motion of the centre of gravity of the human body during level walking. I. Normal subjects at low and intermediate walking speeds.

    PubMed

    Tesio, L; Lanzi, D; Detrembleur, C

    1998-03-01

    OBJECTIVE: To measure the mechanical energy changes of the centre of gravity (CG) of the body in the forward, lateral and vertical direction during normal level walking at intermediate and low speeds. DESIGN: Eight healthy adults performed successive walks at speeds ranging from 0.25 to 1.75 m s(-1) over a dedicated force platform system. BACKGROUND: In previous studies, it was shown that the motion of the CG during gait can be altered more than the motion of individual segments. However, more detailed normative data are needed for clinical analysis. METHODS: The positive work done during the step to accelerate the body CG in the forward direction, W(f), to lift it, W(v), to accelerate it in the lateral direction, W(I), and the actual work done by the muscles to maintain its motion with respect to the ground ('external' work), W(ext), were measured. This allowed the calculation of the pendulum-like transfer between gravitational potential energy and kinetic energy of the CG, (percentage recovery, R). At the optimal speed of about 1.3 m s(-1), this transfer allows saving of as much as 65% of the muscular work which would have been otherwise needed to keep the body in motion with respect to the ground. The distance covered by the CG at each step either forward (step length, S(I)), or vertically (vertical displacement, S(v)) was also recorded. RESULTS: W(I) was, as a median, only 1.6-5.9% of W(ext). This ratio was higher, the lower the speed. At each step, W(ext) is needed to sustain two distinct increments of the total mechanical energy of the CG, E(tot). The increment a takes place during the double stance phase; the increment b takes place during the single stance phase. Both of these increments increased with speed. Over the speed range analyzed, the power spent to to sustain the a increment was 2.8-3.9 times higher than the power spent to sustain the b increment. PMID:11415774

  15. HIGH LEVELS OF URANIUM IN GROUNDWATER OF ULAANBAATAR, MONGOLIA

    PubMed Central

    Nriagu, Jerome; Nam, Dong-Ha; Ayanwola, Titilayo A.; Dinh, Hau; Erdenechimeg, Erdenebayar; Ochir, Chimedsuren; Bolormaa, Tsend-Ayush

    2011-01-01

    Water samples collected from 129 wells in seven of the nine sub-divisions of Ulaanbaatar were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using Clean Lab methods. The levels of many trace elements were found to be very low with the average concentrations (ranges in brackets) being 0.9 (<0.1-7.9) ?g/L for As; 7.7 (0.12-177) ?g/L for Mn; 0.2 (<0.05-1.9) ?g/L for Co; 16 (<0.1-686) ?g/L for Zn; 0.7 (<0.1-1.8) ?g/L for Se; <0.1 (<0.02-0.69) ?g/L for Cd; and 1.3 (<0.02-32) ?g/L for Pb. The levels of uranium were surprisingly elevated (mean, 4.6 ?g/L; range <0.01-57 ?g/L, with the values for many samples exceeding the World Health Organization's guideline of 15 ?g/L for uranium in drinking water. Local rocks and soils appear to be the natural source of the uranium. The levels of uranium in Ulaanbaatar's groundwater are in the range that has been associated with nephrotoxicity, high blood pressure, bone dysfunction and likely reproductive impairment in human populations. We consider the risk associated with drinking the groundwater with elevated levels of uranium in Ulaanbaatar to be a matter for some public health concern and conclude that the paucity of data on chronic effects of low level exposure is a risk factor for continuing the injury to many people in this city. PMID:22142646

  16. Proof of concept and performance optimization of high gravity batch-type centrifugal dryer for dewatering fine coal. Final report, September 20, 1989--September 21, 1991

    SciTech Connect

    Smith, L.B.; Durney, T.

    1991-12-31

    The primary objective of the project was to assemble, analyze and make use of those data that could help to clearly identify, optimize and confirm the technical and economic advantages that the new high gravity centrifugal dryer technology can provide to the coal industry and to end users. Other objectives were: to confirm the feasibility of the dryer for drying coals from a number of different seams; to use the data base for optimizing the dryer`s systems, and: to produce projected technical and economic comparisons with thermal dryers as applied to an existing coal processing plant flow sheet. (JL)

  17. High-level neutron coincidence counter maintenance manual

    SciTech Connect

    Swansen, J.; Collinsworth, P.

    1983-05-01

    High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included.

  18. Corrosion and failure processes in high-level waste tanks

    SciTech Connect

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L.

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  19. High-level wastes: DOE names three sites for characterization

    SciTech Connect

    1986-07-01

    DOE announced in May 1986 that there will be there site characterization studies made to determine suitability for a high-level radioactive waste repository. The studies will include several test drillings to the proposed disposal depths. Yucca Mountain, Nevada; Deaf Smith Country, Texas, and Hanford, Washington were identified as the study sites, and further studies for a second repository site in the East were postponed. The affected states all filed suits in federal circuit courts because they were given no advance warning of the announcement of their selection or the decision to suspend work on a second repository. Criticisms of the selection process include the narrowing or DOE options.

  20. Market Designs for High Levels of Variable Generation: Preprint

    SciTech Connect

    Milligan, M.; Holttinen, H.; Kiviluoma, J.; Orths, A.; Lynch, M.; Soder, L.

    2014-10-01

    Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. Because the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations that ensure the efficient integration of renewable generation is a significant challenge. This papers reviews the state of play of market designs for high levels of variable generation in the United States and Europe and considers new developments in both regions.

  1. Modern Alchemy: Solidifying high-level nuclear waste

    SciTech Connect

    Newton, C.C.

    1997-07-01

    The U.S. Department of Energy is putting a modern version of alchemy to work to produce an answer to a decades-old problem. It is taking place at the Savannah River Site (SRS) in Aiken, South Carolina and at the West Valley Demonstration Project (WVDP) near Buffalo, New York. At both locations, contractor Westinghouse Electric Corporation is applying technology that is turning liquid high-level radioactive waste (HLW) into a stabilized, durable glass for safer and easier management. The process is called vitrification. SRS and WVDP are now operating the nation`s first full-scale HLW vitrification plants.

  2. First results from a high-speed infrared imaging system for the observation of gravity waves in OH airglow

    NASA Astrophysics Data System (ADS)

    Bittner, Michael; Hannawald, Patrick; Schmidt, Carsten; Wst, Sabine

    2015-04-01

    The OH-airglow-layer is concentrated at a height of about 87 km with a half-width of approximately 3 km. Observing the infrared emissions of the vibrational-rotational excited OH moelcules offers a unique possibility for studying atmospheric dynamics. Especially, atmospheric gravity waves are prominent features in the measurements. Since December 2013 the new imaging system FAIm (Fast Infrared Imager) for the study of smaller-scale features (both in space and time)is operational at the NDMC (Network for the Detection of Mesospheric Change, http://wdc.dlr.de/ndmc)station Oberpfaffenhofen. Covering the brightest OH vibrational bands between 1.3 and 1.7micrometer, the imaging system can acquire 2 frames per second. The field of view is approximately 50 km x 60 km at the mesopause height with a mean spatial resolution of 200 m. More than 370 nights of observation have successfully been performed already. The observations show a large variety of atmospheric waves with horizontal wavelengths down to less than 3km, different directions of propagation and phase velocities varying from nearly 0 m/s (quasi stationary waves) to more than 50 m/s. We present the experimental setup and will show first results. Especially, spatio-temporal sequences of the generation of smaller scale gravity wave fields as well as their turbulent dissipation will be shown. An outlook will be given to planned future simultaneous measurements from different stations in the alpine region in order to achieve some stereoscopic information about gravity wave fields.

  3. High-level waste melter alternatives assessment report

    SciTech Connect

    Calmus, R.B.

    1995-02-01

    This document describes the Tank Waste Remediation System (TWRS) High-Level Waste (HLW) Program`s (hereafter referred to as HLW Program) Melter Candidate Assessment Activity performed in fiscal year (FY) 1994. The mission of the TWRS Program is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and encapsulated strontium and cesium isotopic sources) in an environmentally sound, safe, and cost-effective manner. The goal of the HLW Program is to immobilize the HLW fraction of pretreated tank waste into a vitrified product suitable for interim onsite storage and eventual offsite disposal at a geologic repository. Preparation of the encapsulated strontium and cesium isotopic sources for final disposal is also included in the HLW Program. As a result of trade studies performed in 1992 and 1993, processes planned for pretreatment of tank wastes were modified substantially because of increasing estimates of the quantity of high-level and transuranic tank waste remaining after pretreatment. This resulted in substantial increases in needed vitrification plant capacity compared to the capacity of original Hanford Waste Vitrification Plant (HWVP). The required capacity has not been finalized, but is expected to be four to eight times that of the HWVP design. The increased capacity requirements for the HLW vitrification plant`s melter prompted the assessment of candidate high-capacity HLW melter technologies to determine the most viable candidates and the required development and testing (D and T) focus required to select the Hanford Site HLW vitrification plant melter system. An assessment process was developed in early 1994. This document describes the assessment team, roles of team members, the phased assessment process and results, resulting recommendations, and the implementation strategy.

  4. Laser welding in a reduced gravity environment

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Kaukler, William F.

    1992-01-01

    Preliminary results on the effects of reduced gravity on laser welding of stainless steel and other materials are reported. Laser welding experiments using a low power (10-18 watts) Nd-YAG laser have been performed on the NASA KC-135, which flies parabolic maneuvers to simulate reduced gravity conditions. Experiments on 0.005-0.010 inch thick stainless steel samples displayed a pronounced change in weld bead width, depth of penetration and surface ripple with changes in gravity level.

  5. Thermosyphon Flooding in Reduced Gravity Environments

    NASA Technical Reports Server (NTRS)

    Gibson, Marc Andrew

    2013-01-01

    An innovative experiment to study the thermosyphon flooding limits was designed and flown on aparabolic flight campaign to achieve the Reduced Gravity Environments (RGE) needed to obtainempirical data for analysis. Current correlation models of Faghri and Tien and Chung do not agreewith the data. A new model is presented that predicts the flooding limits for thermosyphons inearths gravity and lunar gravity with a 95 confidence level of +- 5W.

  6. Threshold Gravity Determination and Artificial Gravity Studies Using Magnetic Levitation

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F.

    2005-01-01

    What is the threshold gravity (minimum gravity level) required for the nominal functioning of the human system? What dosage is required (magnitude and duration)? Do human cell lines behave differently in microgravity in response to an external stimulus? The critical need for a variable gravity simulator is emphasized by recent experiments on human epithelial cells and lymphocytes on the Space Shuttle clearly showing that cell growth and function are markedly different from those observed terrestrially. Those differences are also dramatic between cells grown in space and those in Rotating Wall Vessels (RWV), or NASA bioreactor often used to simulate microgravity, indicating that although morphological growth patterns (three dimensional growth) can be successfully simulated using RWVs, cell function performance is not reproduced - a critical difference. If cell function is dramatically affected by gravity off-loading, then cell response to stimuli such as radiation, stress, etc. can be very different from terrestrial cell lines. Yet, we have no good gravity simulator for use in study of these phenomena. This represents a profound shortcoming for countermeasures research. We postulate that we can use magnetic levitation of cells and tissue, through the use of strong magnetic fields and field gradients, as a terrestrial microgravity model to study human cells. Specific objectives of the research are: 1. To develop a tried, tested and benchmarked terrestrial microgravity model for cell culture studies; 2. Gravity threshold determination; 3. Dosage (magnitude and duration) of g-level required for nominal functioning of cells; 4. Comparisons of magnetic levitation model to other models such as RWV, hind limb suspension, etc. and 5. Cellular response to reduced gravity levels of Moon and Mars.

  7. Climatology of gravity waves over Poker Flat, Alaska for 1983

    NASA Technical Reports Server (NTRS)

    Balsley, B. B.; Garello, R.

    1986-01-01

    An analysis of short-period wind fluctuations over Poker Flat, Alaska, obtained using the Poker Flat mesosphere-stratosphere-troposphere radar is presented. Results are shown for the troposphere and lower stratosphere as well as for the upper mesosphere and lower thermosphere. Contours depict various levels of wind variance (m2s-2). These results pertain only to wind fluctuation periods lying between one and six hours. These particular fluctuations are generally considered to arise primarily from atmospheric gravity waves. Insofar as this is true, the figure thus describes a general climatology of gravity waves at high latitudes.

  8. Cellular basis of gravity resistance in plants

    NASA Astrophysics Data System (ADS)

    Hoson, Takayuki; Matsumoto, Shouhei; Inui, Kenichi; Zhang, Yan; Soga, Kouichi; Wakabayashi, Kazuyuki; Hashimoto, Takashi

    Mechanical resistance to the gravitational force is a principal gravity response in plants distinct from gravitropism. In the final step of gravity resistance, plants increase the rigidity of their cell walls via modifications to the cell wall metabolism and apoplastic environment. We studied cellular events that are related to the cell wall changes under hypergravity conditions produced by centrifugation. Hypergravity induced reorientation of cortical microtubules from transverse to longitudinal directions in epidermal cells of stem organs. In Arabidopsis tubulin mutants, the percentage of cells with longitudinal microtubules was high even at 1 g, and it was further increased by hypergravity. Hypocotyls of tubulin mutants also showed either left-handed or right-handed helical growth at 1 g, and the degree of twisting phenotype was intensified under hypergravity conditions. The left-handed helical growth mutants had right-handed microtubule arrays, whereas the right-handed mutant had left-handed arrays. There was a close correlation between the alignment angle of epidermal cell files and the alignment of cortical microtubules. Gadolinium ions suppressed both the twisting phenotype and reorientation of microtubules in tubulin mutants. These results support the hypothesis that cortical microtubules play an es-sential role in maintenance of normal growth phenotype against the gravitational force, and suggest that mechanoreceptors are involved in modifications to morphology and orientation of microtubule arrays by hypergravity. Actin microfilaments, in addition to microtubules, may be involved in gravity resistance. The nucleus of epidermal cells of azuki bean epicotyls, which is present almost in the center of the cell at 1 g, was displaced to the cell bottom by increasing the magnitude of gravity. Cytochalasin D stimulated the sedimentation by hypergravity of the nu-cleus, suggesting that the positioning of the nucleus is regulated by actin microfilaments, which is affected by gravity. We also examined the effects of hypergravity on the osmotic properties of azuki bean epicotyls, and found that epicotyls were capable of maintaining osmoregulation even under hypergravity conditions at least for a short period. The increase in level of total osmotic solutes was suppressed by long-term hypergravity treatment, which was accounted by suppres-sion of translocation of organic solutes such as sugars and amino acids. These various cellular events may contribute to sustaining the cell wall changes or cooperate with the cell wall in gravity resistance. Space experiments on the International Space Station will confirm whether this view is applicable to plant resistance to 1 g gravity, as to the resistance to hypergravity.

  9. Pupil responses to high-level image content.

    PubMed

    Naber, Marnix; Nakayama, Ken

    2013-01-01

    The link between arousal and pupil dilation is well studied, but it is less known that other cognitive processes can trigger pupil responses. Here we present evidence that pupil responses can be induced by high-level scene processing, independent of changes in low-level features or arousal. In Experiment 1, we recorded changes in pupil diameter of observers while they viewed a variety of natural scenes with or without a sun that were presented either upright or inverted. Image inversion had the strongest effect on the pupil responses. The pupil constricted more to the onset of upright images as compared to inverted images. Furthermore, the amplitudes of pupil constrictions to viewing images containing a sun were larger relative to control images. In Experiment 2, we presented cartoon versions of upright and inverted pictures that included either a sun or a moon. The image backgrounds were kept identical across conditions. Similar to Experiment 1, upright images triggered pupil constrictions with larger amplitudes than inverted images and images of the sun evoked greater pupil contraction than images of the moon. We suggest that the modulations of pupil responses were due to higher-level interpretations of image content. PMID:23685390

  10. Unexpectedly high mercury level in pelleted commercial fish feed

    SciTech Connect

    Choi, M.H.; Cech, J.J. Jr.

    1998-10-01

    An unexpectedly high mercury (Hg) level was found in a pelleted commercial fish feed used to feed fish in laboratory and fish farm settings. Mean total Hg (T-Hg) concentration in the commercial fish pellets was 66 ppb. Mean total selenium (T-Se) concentration in the pellets was 1,120 ppb (ranging from 790 to 1,360 ppb). Total Hg and Se in the whole blood of Sacramento blackfish and in the fish feed were determined by inductively coupled plasma-mass spectrometry (ICP-MS). During a 10-week sampling period T-Hg in blood fluctuated between 35 and 56 ppb. A highly significant, positive correlation was found between T-Hg in the fish blood and in the fish feed through the sampling period. On the other hand, no correlation was found between T-Se in the fish feed and T-Hg or T-Se blood level. Researchers working with fish in Hg studies need to know that fish pellets may contain Hg and to consider the influence of these pellets in their results.

  11. Spent fuel and high-level radioactive waste transportation report

    SciTech Connect

    Not Available

    1989-11-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by the Southern States Energy Board (SSEB) in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste issues. In addition, this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages sew be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  12. Spent Fuel and High-Level Radioactive Waste Transportation Report

    SciTech Connect

    Not Available

    1992-03-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by SSEB in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste Issues. In addition. this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages will be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  13. Spent fuel and high-level radioactive waste transportation report

    SciTech Connect

    Not Available

    1990-11-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by the Southern States Energy Board (SSEB) in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste issues. In addition, this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages will be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  14. How to achieve high-level expression of microbial enzymes

    PubMed Central

    Liu, Long; Yang, Haiquan; Shin, Hyun-dong; Chen, Rachel R.; Li, Jianghua; Du, Guocheng; Chen, Jian

    2013-01-01

    Microbial enzymes have been used in a large number of fields, such as chemical, agricultural and biopharmaceutical industries. The enzyme production rate and yield are the main factors to consider when choosing the appropriate expression system for the production of recombinant proteins. Recombinant enzymes have been expressed in bacteria (e.g., Escherichia coli, Bacillus and lactic acid bacteria), filamentous fungi (e.g., Aspergillus) and yeasts (e.g., Pichia pastoris). The favorable and very advantageous characteristics of these species have resulted in an increasing number of biotechnological applications. Bacterial hosts (e.g., E. coli) can be used to quickly and easily overexpress recombinant enzymes; however, bacterial systems cannot express very large proteins and proteins that require post-translational modifications. The main bacterial expression hosts, with the exception of lactic acid bacteria and filamentous fungi, can produce several toxins which are not compatible with the expression of recombinant enzymes in food and drugs. However, due to the multiplicity of the physiological impacts arising from high-level expression of genes encoding the enzymes and expression hosts, the goal of overproduction can hardly be achieved, and therefore, the yield of recombinant enzymes is limited. In this review, the recent strategies used for the high-level expression of microbial enzymes in the hosts mentioned above are summarized and the prospects are also discussed. We hope this review will contribute to the development of the enzyme-related research field. PMID:23686280

  15. ATW system impact on high-level waste

    SciTech Connect

    Arthur, E.D.

    1992-12-01

    This report discusses the Accelerator Transmutation of Waste (ATW) concept which aims at destruction of key long-lived radionuclides in high-level nuclear waste (HLW), both fission products and actinides. This focus makes it different from most other transmutation concepts which concentrate primarily on actinide burning. The ATW system uses an accelerator-driven, sub-critical assembly to create an intense thermal neutron environment for radionuclide transmutation. This feature allows rapid transmutation under low-inventory system conditions, which in turn, has a direct impact on the size of chemical separations and materials handling components of the system. Inventories in ATW are factors of eight to thirty times smaller than reactor systems of equivalent thermal power. Chemical separations systems are relatively small in scale and can be optimized to achieve high decontamination factors and minimized waste streams. The low-inventory feature also directly impacts material amounts remaining in the system at its end of life. In addition to its low-inventory operation, the accelerator-driven neutron source features of ATW are key to providing a sufficient level of neutrons to allow transmutation of long-lived fission products.

  16. Predicting high levels of multitasking reduces between-tasks interactions.

    PubMed

    Fischer, Rico; Dreisbach, Gesine

    2015-12-01

    The simultaneous handling of 2 tasks requires shielding of the prioritized primary task (T1) from interference caused by the secondary task (T2) processing. Such interactions between tasks (e.g., between-task interference, or crosstalk) depend on the similarity of both tasks and are especially pronounced when both tasks overlap strongly in time. In the present study we investigated whether between-tasks interference can be reduced when specific items do not predict the level of interference but instead the degree of temporal proximity between both tasks. We implemented an item-specific proportion manipulation of temporal task overlap (stimulus onset asynchrony [SOA]). Selected stimuli of T1 predicted high temporal task overlap (short SOAs) in 80% of trials, whereas other stimuli of T1 predicted low temporal task overlap (long SOAs) in 80% of trials. Results showed that the predictive value of T1 stimuli determined the adjustment of T1 shielding. That is, interference from the secondary task was significantly reduced for items predicting high temporal task overlap compared to items predicting low temporal task overlap. It is important to note that task shielding was not initiated by predicting the actual conflict level (i.e., whether T1 and T2 required compatible/incompatible responses) between tasks but by specific items predicting conditions in which 2 tasks are likely to interact (i.e., short vs. long SOA). These findings offer new insights into the specificity of contextual bottom-up regulations of cognitive control. PMID:26480246

  17. High metabolic level in patients with familial amyotrophic lateral sclerosis.

    PubMed

    Funalot, Benoit; Desport, Jean-Claude; Sturtz, Franck; Camu, William; Couratier, Philippe

    2009-04-01

    An abnormally elevated level of resting energy expenditure (REE, measured by indirect calorimetry) has been reported in a subset of patients with sporadic amyotrophic lateral sclerosis (SALS). Hypermetabolism (measured REE/calculated REE (cREE)> or =1.1, or 110%) has also been observed in transgenic mice harbouring ALS-causing mutations in the SOD1 gene. By contrast, the REE of patients with familial amyotrophic lateral sclerosis (FALS) has never been assessed. Our objective was to evaluate the metabolic and nutritional parameters of FALS patients and to compare them with those of SALS patients, and search for correlations with clinical parameters. Eleven patients with FALS (from 10 different families, none carrying a SOD1 mutation) were evaluated by indirect calorimetry in our centre. As a control group, we used a sample of 33 patients with SALS, matched for age and sex with the FALS patients. 11/11 (100%) patients with FALS were hypermetabolic, compared to 17/33 (52%) patients with SALS (p=0.009). Measured REE (mREE) and mREE/cREE (metabolic level) were significantly higher in FALS patients than in SALS patients (p=0.03 and p=0.0008, respectively). No correlation was found between metabolic measures and neurological or respiratory parameters. In conclusion, hypermetabolism appears to be a common feature of subjects with FALS, suggesting that this impairment of energy homeostasis may be genetically driven. The high metabolic level of FALS patients should be taken into account for their nutritional management (need for a high-energy diet to prevent malnutrition). PMID:18792852

  18. Department of Energy pretreatment of high-level and low-level wastes

    SciTech Connect

    McGinnis, C.P.; Hunt, R.D.

    1995-12-31

    The remediation of the 1 {times} 10{sup 8} gal of highly radioactive waste in the underground storage tanks (USTs) at five US Department of Energy (DOE) sites is one of DOE`s greatest challenges. Therefore, the DOE Office of Environmental Management has created the Tank Focus Area (TFA) to manage an integrated technology development program that results in the safe and efficient remediation of UST waste. The TFA has divided its efforts into five areas, which are safety, characterization, retrieval/closure, pretreatment, and immobilization. All DOE pretreatment activities are integrated by the Pretreatment Technical Integration Manager of the TFA. For FY 1996, the 14 pretreatment tasks are divided into 3 systems: supernate separations, sludge treatment, and solid/liquid separation. The plans and recent results of these TFA tasks, which include two 25,000-gal demonstrations and two former TFA tasks on Cs removal, are presented. The pretreatment goals are to minimize the volume of high-level waste and the radioactivity in low-level waste.

  19. Confidence Level and Sensitivity Limits in High Contrast Imaging

    SciTech Connect

    Marois, C; LaFreniere, D; Macintosh, B; Doyon, R

    2008-06-02

    In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3 x 10{sup -7} confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

  20. Confidence Level and Sensitivity Limits in High Contrast Imaging

    SciTech Connect

    Marois, C

    2007-11-07

    In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3 x 10{sup -7} confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

  1. High-Level Microsatellite Instability in Appendiceal Carcinomas

    PubMed Central

    Taggart, Melissa W.; Galbincea, John; Mansfield, Paul F.; Fournier, Keith F.; Royal, Richard E.; Overman, Michael J.; Rashid, Asif; Abraham, Susan C.

    2014-01-01

    High-level microsatellite instability (MSI-high) is found in approximately 15% of all colorectal adenocarcinomas (CRCs) and in at least 20% of right-sided cancers. It is most commonly due to somatic hypermethylation of the MLH1 gene promoter region, with familial cases (Lynch syndrome) representing only 23% of CRCs overall. In contrast to CRC, MSI-high in appendiceal adenocarcinomas is rare. Only four MSI-high appendiceal carcinomas and one MSI-high appendiceal serrated adenoma have been previously reported, and the prevalence of MSI in the appendix is unknown. We identified 108 appendiceal carcinomas from M. D. Anderson Cancer Center in which MSI status had been assessed by immunohistochemistry for the DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 (n=83), polymerase chain reaction (n=7), or both (n=18). Three cases (2.8%) were MSI-high and one was MSI-low. The three MSI-high cases included: 1) a poorly differentiated nonmucinous adenocarcinoma with loss of MLH1/PMS2 expression, lack of MLH1 promoter methylation, and lack of BRAF gene mutation, but no detected germline mutation in MLH1 from a 39-year-old man; 2) an undifferentiated carcinoma with loss of MSH2/MSH6, but no detected germline mutation in MSH2 or TACSTD1, from a 59-year-old woman; and 3) a moderately differentiated mucinous adenocarcinoma arising in a villous adenoma with loss of MSH2/MSH6 expression, in a 38-year-old man with a strong family history of CRC who declined germline testing. When the overall group of appendiceal carcinomas was classified according to histologic features and precursor lesions, the frequencies of MSI-high were: 3 of 108 (2.8%) invasive carcinomas, 3 of 96 (3.1%) invasive carcinomas that did not arise from a background of goblet cell carcinoid, and 0 of 12 (0%) signet ring and mucinous carcinomas arising in goblet cell carcinoid tumors. These findings, in conjunction with the previously reported MSI-high appendiceal carcinomas, highlight the low prevalence of MSI in the appendix as compared to the right colon and suggest that MLH1 promoter methylation is not a mechanism for microsatellite instability in this location. PMID:23648460

  2. Granular Superconductors and Gravity

    NASA Technical Reports Server (NTRS)

    Noever, David; Koczor, Ron

    1999-01-01

    As a Bose condensate, superconductors provide novel conditions for revisiting previously proposed couplings between electromagnetism and gravity. Strong variations in Cooper pair density, large conductivity and low magnetic permeability define superconductive and degenerate condensates without the traditional density limits imposed by the Fermi energy (approx. 10(exp -6) g cu cm). Recent experiments have reported anomalous weight loss for a test mass suspended above a rotating Type II, YBCO superconductor, with a relatively high percentage change (0.05-2.1%) independent of the test mass' chemical composition and diamagnetic properties. A variation of 5 parts per 104 was reported above a stationary (non-rotating) superconductor. In experiments using a sensitive gravimeter, bulk YBCO superconductors were stably levitated in a DC magnetic field and exposed without levitation to low-field strength AC magnetic fields. Changes in observed gravity signals were measured to be less than 2 parts in 108 of the normal gravitational acceleration. Given the high sensitivity of the test, future work will examine variants on the basic magnetic behavior of granular superconductors, with particular focus on quantifying their proposed importance to gravity.

  3. AIRS high-resolution stratospheric temperature retrievals evaluated with operational Level-2 data and ERA-Interim

    NASA Astrophysics Data System (ADS)

    Meyer, Catrin I.; Hoffmann, Lars

    2015-04-01

    The Atmospheric InfraRed Sounder (AIRS) aboard NASA's Aqua satellite provides stratospheric temperature observations for a variety of scientific tasks. However, the horizontal resolution of the operational temperature retrievals is generally not sufficient for studies of gravity waves. The retrieval discussed here provides stratospheric temperature profiles for each individual AIRS footprint and therefore has nine times better horizontal sampling than the operational data. The retrieval configuration is optimized so that the results provide a trade-off between spatial resolution and retrieval noise which is considered optimal for gravity wave analysis. Here the quality of the high-resolution data is assessed by comparing a nine-year record (2003 - 2011) of stratospheric temperatures with results from the AIRS operational Level-2 data and the ERA-Interim meteorological reanalysis. Due to the large amount of data we performed a statistical comparison of the high-resolution retrieval and reference data sets based on zonal averages and time-series. The temperature data sets are split into day and night, because the AIRS high-resolution retrieval uses different configurations for day- and night-time conditions to cope with non-LTE effects. The temperature data are averaged on a latitudinal grid with a resolution of one degree. The zonal averages are calculated on a daily basis and show significant day-to-day variability. To further summarize the data we calculated monthly averages from the daily averaged data and also computed zonal means. Additionally, the standard deviation of the three data sets was computed. The comparisons show that the high-resolution temperature data are in good agreement with the reference data sets. The bias in the zonal averages is mostly within ± 2 K and reaches a maximum of 7 K to ERA-Interim and 4 K to the AIRS operational data at the stratopause, which is related to the different resolutions of the data sets. Variability is nearly the same in all three data sets, having maximum standard deviations around the polar vortex in the mid and upper stratosphere. The evaluation presented here indicates that the high-resolution temperature retrievals are well-suited for scientific studies and that they will become a valuable asset for further studies of stratospheric gravity waves. Reference: Meyer, C. I. and L. Hoffmann, Validation of AIRS high-resolution stratospheric temperature retrievals, Proc. SPIE 9242, Remote Sensing of Clouds and the Atmosphere XIX; and Optics in Atmospheric Propagation and Adaptive Systems XVII, 92420L (17 October 2014); doi: 10.1117/12.2066967

  4. Unscreening Modified Gravity in the Matter Power Spectrum.

    PubMed

    Lombriser, Lucas; Simpson, Fergus; Mead, Alexander

    2015-06-26

    Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure and limit the constraints that can be inferred on these gravity models from cosmology. We find that by suppressing the contribution of the screened high-density regions in the matter power spectrum, allowing a greater contribution of unscreened low densities, modified gravity models can be more readily discriminated from the concordance cosmology. Moreover, by variation of density thresholds, degeneracies with other effects may be dealt with more adequately. Specializing to chameleon gravity as a worked example for screening in modified gravity, employing N-body simulations of f(R) models and the halo model of chameleon theories, we demonstrate the effectiveness of this method. We find that a percent-level measurement of the clipped power at k<0.3h/Mpc can yield constraints on chameleon models that are more stringent than what is inferred from Solar System tests or distance indicators in unscreened dwarf galaxies. Finally, we verify that our method is also applicable to the Vainshtein mechanism. PMID:26197114

  5. Unscreening Modified Gravity in the Matter Power Spectrum

    NASA Astrophysics Data System (ADS)

    Lombriser, Lucas; Simpson, Fergus; Mead, Alexander

    2015-06-01

    Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure and limit the constraints that can be inferred on these gravity models from cosmology. We find that by suppressing the contribution of the screened high-density regions in the matter power spectrum, allowing a greater contribution of unscreened low densities, modified gravity models can be more readily discriminated from the concordance cosmology. Moreover, by variation of density thresholds, degeneracies with other effects may be dealt with more adequately. Specializing to chameleon gravity as a worked example for screening in modified gravity, employing N -body simulations of f (R ) models and the halo model of chameleon theories, we demonstrate the effectiveness of this method. We find that a percent-level measurement of the clipped power at k <0.3 h /Mpc can yield constraints on chameleon models that are more stringent than what is inferred from Solar System tests or distance indicators in unscreened dwarf galaxies. Finally, we verify that our method is also applicable to the Vainshtein mechanism.

  6. High-Voltage-Input Level Translator Using Standard CMOS

    NASA Technical Reports Server (NTRS)

    Yager, Jeremy A.; Mojarradi, Mohammad M.; Vo, Tuan A.; Blalock, Benjamin J.

    2011-01-01

    proposed integrated circuit would translate (1) a pair of input signals having a low differential potential and a possibly high common-mode potential into (2) a pair of output signals having the same low differential potential and a low common-mode potential. As used here, "low" and "high" refer to potentials that are, respectively, below or above the nominal supply potential (3.3 V) at which standard complementary metal oxide/semiconductor (CMOS) integrated circuits are designed to operate. The input common-mode potential could lie between 0 and 10 V; the output common-mode potential would be 2 V. This translation would make it possible to process the pair of signals by use of standard 3.3-V CMOS analog and/or mixed-signal (analog and digital) circuitry on the same integrated-circuit chip. A schematic of the circuit is shown in the figure. Standard 3.3-V CMOS circuitry cannot withstand input potentials greater than about 4 V. However, there are many applications that involve low-differential-potential, high-common-mode-potential input signal pairs and in which standard 3.3-V CMOS circuitry, which is relatively inexpensive, would be the most appropriate circuitry for performing other functions on the integrated-circuit chip that handles the high-potential input signals. Thus, there is a need to combine high-voltage input circuitry with standard low-voltage CMOS circuitry on the same integrated-circuit chip. The proposed circuit would satisfy this need. In the proposed circuit, the input signals would be coupled into both a level-shifting pair and a common-mode-sensing pair of CMOS transistors. The output of the level-shifting pair would be fed as input to a differential pair of transistors. The resulting differential current output would pass through six standoff transistors to be mirrored into an output branch by four heterojunction bipolar transistors. The mirrored differential current would be converted back to potential by a pair of diode-connected transistors, which, by virtue of being identical to the input transistors, would reproduce the input differential potential at the output

  7. Do Highly Effective Principals Also Have High Levels of Cultural Intelligence?

    ERIC Educational Resources Information Center

    Naughton, Whitney Michelle

    2010-01-01

    Purpose: The purpose of this study was to determine if elementary school principals who exhibit characteristics of highly effective principals also possess high levels of cultural intelligence. Methodology: Three instruments were used in this study, combining both qualitative and quantitative approaches to the collection of data. The first

  8. LIQUIDUS TEMPERATURE AND PRIMARY CRYSTALLIZATION PHASES IN HIGH-ZIRCONIA HIGH-LEVEL WASTE BOROSILICATE GLASSES

    EPA Science Inventory

    Liquidus temperature (TL) studies of high-Zr high-level waste (HLW) borosilicate glasseshave identified three primary phases: baddelyite (ZrO2), zircon (ZrSiO4), and alkali-zirconiumsilicates, such as parakeldyshite (Na2ZrSi2O7). Using published TL data for HLW glasses withthe...

  9. Modeling and optimization of defense high level waste removal sequencing

    NASA Astrophysics Data System (ADS)

    Paul, Pran Krishna

    A novel methodology has been developed which makes possible a very fast running computational tool, capable of performing 30 to 50 years of simulation of the entire Savannah River Site (SRS) high level waste complex in less than 2 minutes on a work station. The methodology has been implemented in the Production Planning Model (ProdMod) simulation code which uses Aspen Technology's dynamic simulation software development package SPEEDUP. ProdMod is a pseudo-dynamic simulation code solely based on algebraic equations, using no differential equations. The dynamic nature of the plant process is captured using linear constructs in which the time dependence is implicit. Another innovative approach implemented in ProdMod development is the mapping of event-space on to time-space and vice versa, which accelerates the computation without sacrificing the necessary details in the event-space. ProdMod uses this approach in coupling the time-space continuous simulation with the event-space batch simulation, avoiding the discontinuities inherent in dynamic simulation batch processing. In addition, a general purpose optimization scheme has been devised based on the pseudo-dynamic constructs and the event- and time-space algorithms of ProdMod. The optimization scheme couples a FORTRAN based stand-alone optimization driver with the SPEEDUP based ProdMod simulator to perform dynamic optimization. The scheme is capable of generating single or multiple optimal input conditions for different types of objective functions over single or multiple years of operations depending on the nature of the objective function and operating constraints. The resultant optimal inputs are then interfaced with ProdMod to simulate the dynamic behavior of the waste processing operations. At the conclusion on an optimized advancement step, the simulation parameters are then passed to the optimization driver to generate the next set of optimized parameters. An optimization algorithm using linear programming has been successfully implemented with this general scheme to sequence wastes from different waste tanks for precipitate production and provide optimized sequences to ProdMod for simulating the behavior of the SRS waste complex. Parametric studies using this optimization methodology demonstrate that the devised scheme is appropriate for the real life operations of the SRS waste complex. The computational planning tool based on the coupled simulation and optimization methodology developed in this work is in current use to help planners process the SRS's 34 million gallons of high level radioactive waste efficiently and economically all the way to clean up of all the tanks. This methodology can also be directly applicable to the Hanford Site and aid in the final design and operation of its facilities to process 55 million gallons of high level radioactive waste.

  10. Study of the Earth's short-scale gravity field using the ERTM2160 gravity model

    NASA Astrophysics Data System (ADS)

    Hirt, Christian; Kuhn, Michael; Claessens, Sten; Pail, Roland; Seitz, Kurt; Gruber, Thomas

    2014-12-01

    This paper describes the computation and analysis of the Earth's short-scale gravity field through high-resolution gravity forward modelling using the Shuttle Radar Topography Mission (SRTM) global topography model. We use the established residual terrain modelling technique along with advanced computational resources and massive parallelisation to convert the high-pass filtered SRTM topography - complemented with bathymetric information in coastal zones - to implied short-scale gravity effects. The result is the ERTM2160 model (Earth Residual Terrain Modelled-gravity field with the spatial scales equivalent to spherical-harmonic coefficients up to degree 2160 removed). ERTM2160, used successfully for the construction of the GGMplus gravity maps, approximates the short-scale (i.e., ~10 km down to ~250 m) gravity field in terms of gravity disturbances, quasi/geoid heights and vertical deflections at ~3 billion gridded points within 60 latitude. ERTM2160 reaches maximum values for the quasi/geoid height of ~30 cm, gravity disturbance in excess of 100 mGal, and vertical deflections of ~30? over the Himalaya mountains. Analysis of the ERTM2160 field as a function of terrain roughness shows in good approximation a linear relationship between terrain roughness and gravity effects, with values of ~1.7 cm (quasi/geoid heights), ~11 mGal (gravity disturbances) and 1.5? (vertical deflections) signal strength per 100 m standard deviation of the terrain. These statistics can be used to assess the magnitude of omitted gravity signals over various types of terrain when using degree-2160 gravity models such as EGM2008. Applications for ERTM2160 are outlined including its use in gravity smoothing procedures, augmentation of EGM2008, fill-in for future ultra-high resolution gravity models in spherical harmonics, or calculation of localised or global power spectra of Earth's short-scale gravity field. ERTM2160 is freely available via

  11. High level radioactive waste vitrification process equipment component testing

    NASA Astrophysics Data System (ADS)

    Siemens, D. H.; Health, W. C.; Larson, D. E.; Craig, S. N.; Berger, D. N.; Goles, R. W.

    1985-04-01

    Remote operability and maintainability of vitrification equipment were assessment under shielded cell conditions. The equipment tested will be applied to immobilize high level and transuranic liquid waste slurries that resulted from plutonium production for defense weapons. Equipment tested included: a turntable for handling waste canisters under the melter; a removable discharge cone in the melter overflow section; a thermocouple jumper that extends into a shielded cell; remote instrument and electrical connectors; remote, mechanical, and heat transfer aspects of the melter glass overflow section; a reamer to clean out plugged nozzles in the melter top; a closed circuit camera to view the melter interior; and a device to retrieve samples of the glass product. A test was also conduucted to evaluate liquid metals for use in a liquid metal sealing system.

  12. High level radioactive waste vitrification process equipment component testing

    SciTech Connect

    Siemens, D.H.; Heath, W.O.; Larson, D.E.; Craig, S.N.; Berger, D.N.; Goles, R.W.

    1985-04-01

    Remote operability and maintainability of vitrification equipment were assessed under shielded-cell conditions. The equipment tested will be applied to immobilize high-level and transuranic liquid waste slurries that resulted from plutonium production for defense weapons. Equipment tested included: a turntable for handling waste canisters under the melter; a removable discharge cone in the melter overflow section; a thermocouple jumper that extends into a shielded cell; remote instrument and electrical connectors; remote, mechanical, and heat transfer aspects of the melter glass overflow section; a reamer to clean out plugged nozzles in the melter top; a closed circuit camera to view the melter interior; and a device to retrieve samples of the glass product. A test was also conducted to evaluate liquid metals for use in a liquid metal sealing system.

  13. SIMULANT DEVELOPMENT FOR SAVANNAH RIVER SITE HIGH LEVEL WASTE

    SciTech Connect

    Stone, M; Russell Eibling, R; David Koopman, D; Dan Lambert, D; Paul Burket, P

    2007-09-04

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The HLW is processed in large batches through DWPF; DWPF has recently completed processing Sludge Batch 3 (SB3) and is currently processing Sludge Batch 4 (SB4). The composition of metal species in SB4 is shown in Table 1 as a function of the ratio of a metal to iron. Simulants remove radioactive species and renormalize the remaining species. Supernate composition is shown in Table 2.

  14. Sandia National Laboratories' new high level acoustic test facility

    SciTech Connect

    Rogers, J. D.; Hendrick, D. M.

    1989-01-01

    A high intensity acoustic test facility has been designed and is under construction at Sandia National Laboratories in Albuquerque, NM. The chamber is designed to provide an acoustic environment of 154dB (re 20 {mu}Pa) overall sound pressure level over the bandwidth of 50 Hz to 10,000 Hz. The chamber has a volume of 16,000 cubic feet with interior dimensions of 21.6 ft {times} 24.6 ft {times} 30 ft. The construction of the chamber should be complete by the summer of 1990. This paper discusses the design goals and constraints of the facility. The construction characteristics are discussed in detail, as are the acoustic performance design characteristics. The authors hope that this work will help others in designing acoustic chambers. 12 refs., 6 figs.

  15. Respiratory physiology: adaptations to high-level exercise.

    PubMed

    McKenzie, Donald C

    2012-05-01

    Most exercise scientists would agree that the physiological determinants of peak endurance performance include the capacity to transport oxygen to the working muscle, diffusion from the muscle to the mitochondria, energy production and force generation, all influenced by signals from the central nervous system. In general, the capacity of the pulmonary system far exceeds the demands required for ventilation and gas exchange during exercise. Endurance training induces large and significant adaptations within the cardiovascular, musculoskeletal and haematological systems. However, the structural and functional properties of the lung and airways do not change in response to repetitive physical activity and, in elite athletes, the pulmonary system may become a limiting factor to exercise at sea level and altitude. As a consequence to this respiratory paradox, highly trained athletes may develop intrathoracic and extrathoracic obstruction, expiratory flow limitation, respiratory muscle fatigue and exercise-induced hypoxaemia. All of these maladaptations may influence performance. PMID:22267571

  16. A High-Level Language for Rule-Based Modelling

    PubMed Central

    Pedersen, Michael; Phillips, Andrew; Plotkin, Gordon D.

    2015-01-01

    Rule-based languages such as Kappa excel in their support for handling the combinatorial complexities prevalent in many biological systems, including signalling pathways. But Kappa provides little structure for organising rules, and large models can therefore be hard to read and maintain. This paper introduces a high-level, modular extension of Kappa called LBS-?. We demonstrate the constructs of the language through examples and three case studies: a chemotaxis switch ring, a MAPK cascade, and an insulin signalling pathway. We then provide a formal definition of LBS-? through an abstract syntax and a translation to plain Kappa. The translation is implemented in a compiler tool which is available as a web application. We finally demonstrate how to increase the expressivity of LBS-? through embedded scripts in a general-purpose programming language, a technique which we view as generally applicable to other domain specific languages. PMID:26043208

  17. High Level Waste System Impacts from Acid Dissolution of Sludge

    SciTech Connect

    KETUSKY, EDWARD

    2006-04-20

    This research evaluates the ability of OLI{copyright} equilibrium based software to forecast Savannah River Site High Level Waste system impacts from oxalic acid dissolution of Tank 1-15 sludge heels. Without further laboratory and field testing, only the use of oxalic acid can be considered plausible to support sludge heel dissolution on multiple tanks. Using OLI{copyright} and available test results, a dissolution model is constructed and validated. Material and energy balances, coupled with the model, identify potential safety concerns. Overpressurization and overheating are shown to be unlikely. Corrosion induced hydrogen could, however, overwhelm the tank ventilation. While pH adjustment can restore the minimal hydrogen generation, resultant precipitates will notably increase the sludge volume. OLI{copyright} is used to develop a flowsheet such that additional sludge vitrification canisters and other negative system impacts are minimized. Sensitivity analyses are used to assess the processability impacts from variations in the sludge/quantities of acids.

  18. High Level Nuclear Waste: Status of Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Craig, Paul

    1998-03-01

    The United States, along with other nuclear nations, is committed to storing high-level nuclear waste so as to protect people living many thousands of years hence. Such transgenerational commitment is without precedent. The time scales involved dwarf those associated with the current global climate change debate. The US Department of Energy is exploring a candidate site at Yucca Mountain, NV. A recommendation on the site's suitability is to be made to the President in 2002. I will describe the DoE's ``Total System Performance Assessment'' analytical methodology, and discuss recommendations concerning Yucca Mountain and surrounding issues made by the Nuclear Waste Technical Review Board. ppcraig@ucdavis.edu

  19. Control of high level radioactive waste-glass melters

    SciTech Connect

    Bickford, D.F.; Coleman, C.J.; Hsu, C.L.W.; Eibling, R.E.

    1990-01-01

    A necessary step in Defense Waste Processing Facility (DWPF) melter feed preparation for the immobilization of High Level Radioactive Waste (HLW) is reduction of Hg(II) to Hg(0), permitting steam stripping of the Hg. Denitrition and associated NOx evolution is a secondary effect of the use of formic acid as the mercury-reducing agent. Under certain conditions the presence of transition or noble metals can result in significant formic acid decomposition, with associated CO{sub 2} and H{sub 2} evolution. These processes can result in varying redox properties of melter feed, and varying sequential gaseous evolution of oxidants and hydrogen. Electrochemical methods for monitoring the competing processes are discussed. Laboratory scale techniques have been developed for simulating the large-scale reactions, investigating the relative effectiveness of the catalysts, and the effectiveness of catalytic poisons. The reversible nitrite poisoning of formic acid catalysts is discussed.

  20. Calculates Neutron Production in Canisters of High-level Waste

    Energy Science and Technology Software Center (ESTSC)

    1993-01-15

    ALPHN calculates the (alpha,n) neutron production rate of a canister of vitrified high-level waste. The user supplies the chemical composition of the glass or glass-ceramic and the curies of the alpha-emitting actinides present. The output of the program gives the (alpha,n) neutron production of each actinide in neutrons per second and the total for the canister. The (alpha,n) neutron production rates are source terms only; that is, they are production rates within the glass andmore » do not take into account the shielding effect of the glass. For a given glass composition, the user can calculate up to eight cases simultaneously; these cases are based on the same glass composition but contain different quantities of actinides per canister.« less