WorldWideScience

Sample records for airborne gravity tests

  1. Airborne gravity tests in the Italian area to improve the geoid model of Italy

    DEFF Research Database (Denmark)

    Barzaghi, R; Borghi, A; Keller, K

    2009-01-01

    Airborne gravimetry is an important method for measuring gravity over large unsurveyed areas. This technology has been widely applied in Canada, Antarctica and Greenland to map the gravity fields of these regions and in recent years, in the oil industry. In 2005, two tests in the Italian area were...... performed by ENI in cooperation with the Politecnico di Milano and the Danish National Space Center. To the knowledge of the authors, these were the first experiments of this kind in Italy and were performed over the Ionian coasts of Calabria and the Maiella Mountains. The Calabria test field......, the collocation method applied to compare and merge ground-based and airborne data proved to be efficient and reliable. The standard deviation of the discrepancies between airborne data and collocation upward continued gravity is, in both cases, less than 8 mgal. In the Maiella test, the gravity field obtained...

  2. Merging of airborne gravity and gravity derived from satellite altimetry: Test cases along the coast of greenland

    DEFF Research Database (Denmark)

    Olesen, Arne Vestergaard; Andersen, Ole Baltazar; Tscherning, C.C.

    2002-01-01

    for the use of gravity data especially, when computing geoid models in coastal regions. The presence of reliable marine gravity data for independent control offers an opportunity to study procedures for the merging of airborne and satellite data around Greenland. Two different merging techniques, both based......The National Survey and Cadastre - Denmark (KMS) has for several years produced gravity anomaly maps over the oceans derived from satellite altimetry. During the last four years, KMS has also conducted airborne gravity surveys along the coast of Greenland dedicated to complement the existing...... onshore gravity coverage and fill in new data in the very-near coastal area, where altimetry data may contain gross errors. The airborne surveys extend from the coastline to approximately 100 km offshore, along 6000 km of coastline. An adequate merging of these different data sources is important...

  3. Airborne Gravity: NGS' Gravity Data for EN08 (2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for New York, Vermont, New Hampshire, Massachusettes, Maine, and Canada collected in 2013 over 1 survey. This data set is part of the Gravity...

  4. Airborne Gravity: NGS' Gravity Data for TS01 (2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Puerto Rico and the Virgin Islands collected in 2009 over 1 survey. This data set is part of the Gravity for the Re-definition of the...

  5. Airborne Gravity: NGS' Gravity Data for AN08 (2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2016 over one survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum...

  6. Airborne Gravity: NGS' Gravity Data for CN02 (2013 & 2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Nebraska collected in 2013 & 2014 over 3 surveys. This data set is part of the Gravity for the Re-definition of the American Vertical...

  7. Airborne Gravity: NGS' Gravity Data for EN01 (2011)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for New York, Canada, and Lake Ontario collected in 2011 over 1 survey. This data set is part of the Gravity for the Re-definition of the...

  8. Airborne Gravity: NGS' Gravity Data for AN03 (2010)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2010 and 2012 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American Vertical Datum...

  9. Airborne Gravity: NGS' Gravity Data for EN06 (2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Maine, Canada, and the Atlantic Ocean collected in 2012 over 2 surveys. This data set is part of the Gravity for the Re-definition of the...

  10. Airborne Gravity: NGS' Gravity Data for ES01 (2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Florida, the Bahamas, and the Atlantic Ocean collected in 2013 over 1 survey. This data set is part of the Gravity for the Re-definition of...

  11. Polar gravity fields from GOCE and airborne gravity

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Yidiz, Hasan

    2011-01-01

    Airborne gravity, together with high-quality surface data and ocean satellite altimetric gravity, may supplement GOCE to make consistent, accurate high resolution global gravity field models. In the polar regions, the special challenge of the GOCE polar gap make the error characteristics...... of combination models especially sensitive to the correct merging of satellite and surface data. We outline comparisons of GOCE to recent airborne gravity surveys in both the Arctic and the Antarctic. The comparison is done to new 8-month GOCE solutions, as well as to a collocation prediction from GOCE gradients...... in Antarctica. It is shown how the enhanced gravity field solutions improve the determination of ocean dynamic topography in both the Arctic and in across the Drake Passage. For the interior of Antarctica, major airborne gravity programs are currently being carried out, and there is an urgent need...

  12. Airborne Gravity: NGS' Airborne Gravity Data for AN01 (2009-2010)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2009-2010 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American Vertical Datum...

  13. Airborne Gravity: NGS' Gravity Data for ES03 (2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Maryland, Pennsylvania, New Jersey, West Virginia, Virginia, Delaware, and the Atlantic Ocean collected in 2013 over 1 survey. This data...

  14. Airborne Gravity: NGS' Gravity Data for EN10 (2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for New York, Pennsylvania, New Jersey, Connecticut and the Atlantic Ocean collected in 2013 over 1 survey. This data set is part of the...

  15. Airborne Gravity: NGS' Gravity Data for EN09 (2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Massachusetts, Connecticut, Rhode Island, New Hampshire, New York, and the Atlantic Ocean collected in 2012 over 1 survey. This data set is...

  16. Airborne Gravity Data Denoising Based on Empirical Mode Decomposition: A Case Study for SGA-WZ Greenland Test Data

    DEFF Research Database (Denmark)

    Zhao, Lei; Wu, Meiping; Forsberg, René

    2015-01-01

    Surveying the Earth's gravity field refers to an important domain of Geodesy, involving deep connections with Earth Sciences and Geo-information. Airborne gravimetry is an effective tool for collecting gravity data with mGal accuracy and a spatial resolution of several kilometers. The main obstacle......-WZ carried out in Greenland. Comparing to the solutions of using finite impulse response filter (FIR), the new results are improved by 40% and 10% of root mean square (RMS) of internal consistency and external accuracy, respectively....

  17. Airborne Gravity: NGS' Gravity Data for AN05 (2011)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2011 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  18. Airborne Gravity: NGS' Gravity Data for AN06 (2011)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2011 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  19. Airborne Gravity: NGS' Gravity Data for CS08 (2015)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for CS08 collected in 2006 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  20. Airborne Gravity: NGS' Gravity Data for AS02 (2010)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2010 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  1. Airborne Gravity: NGS' Gravity Data for ES02 (2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Florida and the Gulf of Mexico collected in 2013 over 1 survey. This data set is part of the Gravity for the Re-definition of the American...

  2. Airborne Gravity: NGS' Gravity Data for AN04 (2010)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2010 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  3. Airborne Gravity: NGS' Gravity Data for CS05 (2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Texas collected in 2014 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  4. Airborne Gravity: NGS' Gravity Data for CS07 (2014 & 2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Texas collected in 2014 & 2016 over 3 surveys,TX14-2, TX16-1 and TX16-2. This data set is part of the Gravity for the Re-definition of...

  5. Airborne Gravity: NGS' Gravity Data for AS01 (2008)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2008 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  6. Airborne Gravity: NGS' Gravity Data for CS04 (2009)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Texas collected in 2009 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  7. Airborne Gravity: NGS' Gravity Data for AN02 (2010)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2010 over 1 survey. This data set is part of the Gravity for the Re-definition of the American Vertical Datum (GRAV-D)...

  8. Geoid of Nepal from airborne gravity survey

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Einarsson, Indriði

    2011-01-01

    An airborne gravity survey of Nepal was carried out December 2010 in a cooperation between DTU-Space, Nepal Survey Department, and NGA, USA. The entire country was flown with survey lines spaced 6 nm with a King Air aircraft, with a varying flight altitude from 4 to 10 km. The survey operations...... as well as recent GPS-heights of Mt. Everest. The new airborne data also provide an independent validation of GOCE gravity field results at the local ~100 km resolution scale....

  9. Airborne Gravity: NGS' Gravity Data for MS02 (2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data over southern Arizona and New Mexico overlapping into Mexico collected in 2016 over 2 surveys, AZ16-1 and AZ16-2. This data set is part of the...

  10. Geological Mapping of Sabah, Malaysia, Using Airborne Gravity Survey

    DEFF Research Database (Denmark)

    Fauzi Nordin, Ahmad; Jamil, Hassan; Noor Isa, Mohd

    2016-01-01

    Airborne gravimetry is an effective tool for mapping local gravity fields using a combination of airborne sensors, aircraft and positioning systems. It is suitable for gravity surveys over difficult terrains and areas mixed with land and ocean. This paper describes the geological mapping of Sabah...... using airborne gravity surveys. Airborne gravity data over land areas of Sabah has been combined with the marine airborne gravity data to provide a seamless land-to-sea gravity field coverage in order to produce the geological mapping. Free-air and Bouguer anomaly maps (density 2.67 g/cm3) have been...... derived from the airborne data both as simple ad-hoc plots (at aircraft altitude), and as final plots from the downward continued airborne data, processed as part of the geoids determination. Data are gridded at 0.025 degree spacing which is about 2.7 km and the data resolution of the filtered airborne...

  11. Airborne Test Bed Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Laboratory operates the main hangar on the Hanscom Air Force Base flight line. This very large building (~93,000sqft) accommodates the Laboratory's airborne test...

  12. Urine specific gravity test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003587.htm Urine specific gravity test To use the sharing features on this page, please enable JavaScript. Urine specific gravity is a laboratory test that shows the concentration ...

  13. Airborne Gravity: NGS' Gravity Data for EN07 (2012-2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Maine and Canada collected in 2012 and 2013 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American...

  14. Airborne Gravity: NGS' Gravity Data for AS03 (2010-2012)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2010 and 2012 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American Vertical Datum...

  15. Airborne Gravity: NGS' Gravity Data for CS02 (2008-2009)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Louisana and Mississippi collected in 2008-2009 over 2 surveys. This data set is part of the Gravity for the Re-definition of the American...

  16. Space-Wise approach for airborne gravity data modelling

    Science.gov (United States)

    Sampietro, D.; Capponi, M.; Mansi, A. H.; Gatti, A.; Marchetti, P.; Sansò, F.

    2017-05-01

    Regional gravity field modelling by means of remove-compute-restore procedure is nowadays widely applied in different contexts: it is the most used technique for regional gravimetric geoid determination, and it is also used in exploration geophysics to predict grids of gravity anomalies (Bouguer, free-air, isostatic, etc.), which are useful to understand and map geological structures in a specific region. Considering this last application, due to the required accuracy and resolution, airborne gravity observations are usually adopted. However, due to the relatively high acquisition velocity, presence of atmospheric turbulence, aircraft vibration, instrumental drift, etc., airborne data are usually contaminated by a very high observation error. For this reason, a proper procedure to filter the raw observations in both the low and high frequencies should be applied to recover valuable information. In this work, a software to filter and grid raw airborne observations is presented: the proposed solution consists in a combination of an along-track Wiener filter and a classical Least Squares Collocation technique. Basically, the proposed procedure is an adaptation to airborne gravimetry of the Space-Wise approach, developed by Politecnico di Milano to process data coming from the ESA satellite mission GOCE. Among the main differences with respect to the satellite application of this approach, there is the fact that, while in processing GOCE data the stochastic characteristics of the observation error can be considered a-priori well known, in airborne gravimetry, due to the complex environment in which the observations are acquired, these characteristics are unknown and should be retrieved from the dataset itself. The presented solution is suited for airborne data analysis in order to be able to quickly filter and grid gravity observations in an easy way. Some innovative theoretical aspects focusing in particular on the theoretical covariance modelling are presented too

  17. Analysis of Alabama Airborne Gravity at Three Altitudes: Expected Accuracy and Spatial Resolution from a Future Tibetan Airborne Gravity Survey

    Directory of Open Access Journals (Sweden)

    Chi-Hsun Huang

    2013-01-01

    Full Text Available In situ airborne gravity data at altitudes of 11, 6.3, and 1.7 km over a smooth area of Alabama are used to assess gravity accuracy and errors in upward and downward continuations. Analysis of the Alabama free-air anomaly gravity data at crossover points at the three altitudes suggests 1 - 2 mgal accuracy for the dataset. Gravity data at each altitude are then expanded into local 3D Fourier series, to prepare for continuation. This Fourier representation results in continuation errors at few-mgal level in Alabama, even in the extreme case of downward continuation from 11 km to sea level. The result in Alabama inspires an airborne gravity survey over the rough, inaccessible terrain of Tibet. Similar investigations as in Alabama are made in Tibet using EGM08-derived airborne gravity data at flight altitudes of 10, 5, and 0 km. Bouguer anomalies at the 10-km altitude preserve the major tectonic features of Tibet. Downward continuation errors increase with terrain roughness, but the survey can enhance local tectonic features. This study highlights the value of a future Tibetan airborne gravity survey and points out the expected gravity accuracy and spatial resolution from this survey.

  18. Airborne Gravity: NGS' Gravity Data for ES04 (2013-2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for North Carolina, South Carolina, Virginia, and the Atlantic Ocean collected in 2013 and 2014 over two surveys. This data set is part of the...

  19. Airborne Gravity: NGS' Gravity Data for EN02 (2011-2012)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for New York, Pennsylvania, Ohio, Michigan, Canada and Lake Erie collected in 2011 and 2012 over 3 surveys. This data set is part of the...

  20. The Effects of Lever Arm (Instrument Offset) Error on GRAV-D Airborne Gravity Data

    Science.gov (United States)

    Johnson, J. A.; Youngman, M.; Damiani, T.

    2017-12-01

    High quality airborne gravity collection with a 2-axis, stabilized platform gravity instrument, such as with a Micro-g LaCoste Turnkey Airborne Gravity System (TAGS), is dependent on the aircraft's ability to maintain "straight and level" flight. However, during flight there is constant rotation about the aircraft's center of gravity. Standard practice is to install the scientific equipment close to the aircraft's estimated center of gravity to minimize the relative rotations with aircraft motion. However, there remain small offsets between the instruments. These distance offsets, the lever arm, are used to define the rigid-body, spatial relationship between the IMU, GPS antenna, and airborne gravimeter within the aircraft body frame. The Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project, which is collecting airborne gravity data across the U.S., uses a commercial software package for coupled IMU-GNSS aircraft positioning. This software incorporates a lever arm correction to calculate a precise position for the airborne gravimeter. The positioning software must do a coordinate transformation to relate each epoch of the coupled GNSS-IMU derived position to the position of the gravimeter within the constantly-rotating aircraft. This transformation requires three inputs: accurate IMU-measured aircraft rotations, GNSS positions, and lever arm distances between instruments. Previous studies show that correcting for the lever arm distances improves gravity results, but no sensitivity tests have been done to investigate how error in the lever arm distances affects the final airborne gravity products. This research investigates the effects of lever arm measurement error on airborne gravity data. GRAV-D lever arms are nominally measured to the cm-level using surveying equipment. "Truth" data sets will be created by processing GRAV-D flight lines with both relatively small lever arms and large lever arms. Then negative and positive incremental

  1. Airborne Gravity: NGS' Gravity Data for ES05 (2015-2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Florida and the Atlantic Ocean collected in two surveys, FL15-1 and FL15-2. This data set is part of the Gravity for the Re-definition of...

  2. Airborne Gravity: NGS' Gravity Data for AS04 (2015-2016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne gravity data for Alaska collected in 2015 and 2016 over 2 surveys, AK15 and AK16. This data set is part of the Gravity for the Re-definition of the American...

  3. A comparison of stable platform and strapdown airborne gravity

    DEFF Research Database (Denmark)

    Glennie, C.L.; Schwarz, K.P.; Bruton, A.M.

    2000-01-01

    To date, operational airborne gravity results have been obtained using either a damped two-axis stable platform gravimeter system such as the LaCoste and Romberg (LCR) S-model marine gravimeter or a strapdown inertial navigation system (INS), showing comparable accuracies. In June 1998 three flight...

  4. Airborne gravity field Measurements - status and developments

    DEFF Research Database (Denmark)

    Olesen, Arne Vestergaard; Forsberg, René

    2016-01-01

    English Abstract:DTU-Space has since 1996 carried out large area airborne surveys over both polar, tropical and temperate regions, especially for geoid determination and global geopotential models. Recently we have started flying two gravimeters (LCR and Chekan-AM or inertial navigation systems) ...

  5. Cosmological Tests of Gravity

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Extensions of Einstein’s theory of General Relativity are under investigation as a potential explanation of the accelerating expansion rate of the universe. I’ll present a cosmologist’s overview of attempts to test these ideas in an efficient and unbiased manner. I’ll start by introducing the bestiary of alternative gravity theories that have been put forwards. This proliferation of models motivates us to develop model-independent, agnostic tools for comparing the theory space to cosmological data. I’ll introduce the effective field theory for cosmological perturbations, a framework designed to unify modified gravity theories in terms of a manageable set of parameters. Having outlined the formalism, I’ll talk about the current constraints on this framework, and the improvements expected from the next generation of large galaxy clustering, weak lensing and intensity mapping experiments.

  6. The alpine Swiss-French airborne gravity survey

    Science.gov (United States)

    Verdun, Jérôme; Klingelé, Emile E.; Bayer, Roger; Cocard, Marc; Geiger, Alain; Kahle, Hans-Gert

    2003-01-01

    In February 1998, a regional-scale, airborne gravity survey was carried out over the French Occidental Alps within the framework of the GéoFrance 3-D research program.The survey consisted of 18 NS and 16 EW oriented lines with a spacing of 10 and 20 km respectively, covering the whole of the Western French Alps (total area: 50 000 km2; total distance of lines flown: 10 000 km). The equipment was mounted in a medium-size aircraft (DeHavilland Twin Otter) flowing at a constant altitude of 5100 m a.s.l, and at a mean ground speed of about 280 km h-1. Gravity was measured using a LaCoste & Romberg relative, air/sea gravimeter (type SA) mounted on a laser gyro stabilized platform. Data from 5 GPS antennae located on fuselage and wings and 7 ground-based GPS reference stations were used to determine position and aircraft induced accelerations.The gravimeter passband was derived by comparing the vertical accelerations provided by the gravimeter with those estimated from the GPS positions. This comparison showed that the gravimeter is not sensitive to very short wavelength aircraft accelerations, and therefore a simplified formulation for computing airborne gravity measurements was developed. The intermediate and short wavelength, non-gravitational accelerations were eliminated by means of digital, exponential low-pass filters (cut-off wavelength: 16 km). An important issue in airborne gravimetry is the reliability of the airborne gravity surveys when compared to ground surveys. In our studied area, the differences between the airborne-acquired Bouguer anomaly and the ground upward-continued Bouguer anomaly of the Alps shows a good agreement: the rms of these differences is equal to 7.68 mGal for a spatial resolution of 8 km. However, in some areas with rugged topography, the amplitudes of those differences have a striking correlation with the topography. We then argue that the choice of an appropriate density (reduction by a factor of 10 per cent) for computing the

  7. Functional Testing Airborne Radars

    Science.gov (United States)

    1981-03-27

    recorded, and presented in accordance with this TOP? Yes No Comment : 2. Were the facilities, test equipment, instrumentation, and support accommo- dations...adequate to accomplish the test objectives? Yes No Comment : 3. Have all data collected been reviewed for correctness and completeness? Yes No ... Comment : 4. Were the test results compromised in any way due to insufficient test planning? Yes No . Comment : 5. Were the test results compromised in any

  8. Modelling airborne gravity data by means of adapted Space-Wise approach

    Science.gov (United States)

    Sampietro, Daniele; Capponi, Martina; Hamdi Mansi, Ahmed; Gatti, Andrea

    2017-04-01

    Regional gravity field modelling by means of remove - restore procedure is nowadays widely applied to predict grids of gravity anomalies (Bouguer, free-air, isostatic, etc.) in gravimetric geoid determination as well as in exploration geophysics. Considering this last application, due to the required accuracy and resolution, airborne gravity observations are generally adopted. However due to the relatively high acquisition velocity, presence of atmospheric turbulence, aircraft vibration, instrumental drift, etc. airborne data are contaminated by a very high observation error. For this reason, a proper procedure to filter the raw observations both in the low and high frequency should be applied to recover valuable information. In this work, a procedure to predict a grid or a set of filtered along track gravity anomalies, by merging GGM and airborne dataset, is presented. The proposed algorithm, like the Space-Wise approach developed by Politecnico di Milano in the framework of GOCE data analysis, is based on a combination of along track Wiener filter and Least Squares Collocation adjustment and properly considers the different altitudes of the gravity observations. Among the main differences with respect to the satellite application of the Space-Wise approach there is the fact that, while in processing GOCE data the stochastic characteristics of the observation error can be considered a-priori well known, in airborne gravimetry, due to the complex environment in which the observations are acquired, these characteristics are unknown and should be retrieved from the dataset itself. Some innovative theoretical aspects focusing in particular on the theoretical covariance modelling are presented too. In the end, the goodness of the procedure is evaluated by means of a test on real data recovering the gravitational signal with a predicted accuracy of about 0.25 mGal.

  9. Tests of chameleon gravity

    Science.gov (United States)

    Burrage, Clare; Sakstein, Jeremy

    2018-03-01

    Theories of modified gravity, where light scalars with non-trivial self-interactions and non-minimal couplings to matter—chameleon and symmetron theories—dynamically suppress deviations from general relativity in the solar system. On other scales, the environmental nature of the screening means that such scalars may be relevant. The highly-nonlinear nature of screening mechanisms means that they evade classical fifth-force searches, and there has been an intense effort towards designing new and novel tests to probe them, both in the laboratory and using astrophysical objects, and by reinterpreting existing datasets. The results of these searches are often presented using different parametrizations, which can make it difficult to compare constraints coming from different probes. The purpose of this review is to summarize the present state-of-the-art searches for screened scalars coupled to matter, and to translate the current bounds into a single parametrization to survey the state of the models. Presently, commonly studied chameleon models are well-constrained but less commonly studied models have large regions of parameter space that are still viable. Symmetron models are constrained well by astrophysical and laboratory tests, but there is a desert separating the two scales where the model is unconstrained. The coupling of chameleons to photons is tightly constrained but the symmetron coupling has yet to be explored. We also summarize the current bounds on f( R) models that exhibit the chameleon mechanism (Hu and Sawicki models). The simplest of these are well constrained by astrophysical probes, but there are currently few reported bounds for theories with higher powers of R. The review ends by discussing the future prospects for constraining screened modified gravity models further using upcoming and planned experiments.

  10. Cosmological tests of modified gravity.

    Science.gov (United States)

    Koyama, Kazuya

    2016-04-01

    We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.

  11. Geodetic and geophysical results from a Taiwan airborne gravity survey: Data reduction and accuracy assessment

    DEFF Research Database (Denmark)

    Hwang, C.W.; Hsiao, Y.S.; Shih, H.C.

    2007-01-01

    [ 1] An airborne gravity survey was conducted over Taiwan using a LaCoste and Romberg (LCR) System II air-sea gravimeter with gravity and global positioning system (GPS) data sampled at 1 Hz. The aircraft trajectories were determined using a GPS network kinematic adjustment relative to eight GPS ...... using airborne and surface gravity data and the other using surface data only, and the former yields a better agreement with the GPS-derived geoidal heights. Bouguer anomalies derived from airborne gravity by a rigorous numerical integration reveal important tectonic features....

  12. On the use of airborne gravimetry in gravity field modelling: Experiences from the AGMASCO project

    DEFF Research Database (Denmark)

    Bastos, L.; Cunha, S.; Forsberg, René

    2000-01-01

    of the vertical accelerations acting on the airborne platform from the natural gravity signal. With the advances in DGPS techniques new prospects arise for gravity field recovery which are of great importance for geodesy, geophysics oceanography and satellite navigation. Furthermore, airborne gravimetric...... and the methods validated. Recovery of the gravity values directly from measurements with the Lacoste & Romberg air/sea gravimeter and from measurements with the inertial sensors was analysed. The potential of these sensors to recover gravity and the experience gained within this project are reported here....

  13. Experimental tests of relativistic gravity

    International Nuclear Information System (INIS)

    Damour, Thibault

    2000-01-01

    The confrontation between Einstein's gravitation theory and experimental results, notably binary pulsar data, is summarized and its significance discussed. Experiment and theory agree at the 10 -3 level or better. All the basic structures of Einstein's theory (coupling of gravity matter; propagation and self-interaction of the gravitational field, including in strong field conditions) have been verified. However, the theoretical possibility that scalar couplings be naturally driven toward zero by the cosmological expansion suggests that the present agreement between Einstein's theory and experiment might be compatible with the existence of a long-range scalar contribution to gravity (such as the dilation field, or a moduli field, of string theory). This provides a new theoretical paradigm, and new motivations for improving the experimental tests of gravity

  14. Observational tests of modified gravity

    International Nuclear Information System (INIS)

    Jain, Bhuvnesh; Zhang Pengjie

    2008-01-01

    Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the Universe. Modified gravity theories have richer observational consequences for large-scale structures than conventional dark energy models, in that different observables are not described by a single growth factor even in the linear regime. We examine the relationships between perturbations in the metric potentials, density and velocity fields, and discuss strategies for measuring them using gravitational lensing, galaxy cluster abundances, galaxy clustering/dynamics, and the integrated Sachs-Wolfe effect. We show how a broad class of gravity theories can be tested by combining these probes. A robust way to interpret observations is by constraining two key functions: the ratio of the two metric potentials, and the ratio of the gravitational 'constant' in the Poisson equation to Newton's constant. We also discuss quasilinear effects that carry signatures of gravity, such as through induced three-point correlations. Clustering of dark energy can mimic features of modified gravity theories and thus confuse the search for distinct signatures of such theories. It can produce pressure perturbations and anisotropic stresses, which break the equality between the two metric potentials even in general relativity. With these two extra degrees of freedom, can a clustered dark energy model mimic modified gravity models in all observational tests? We show with specific examples that observational constraints on both the metric potentials and density perturbations can in principle distinguish modifications of gravity from dark energy models. We compare our result with other recent studies that have slightly different assumptions (and apparently contradictory conclusions).

  15. Strapdown Airborne Gravimetry Using a Combination of Commercial Software and Stable-Platform Gravity Estimates

    DEFF Research Database (Denmark)

    Jensen, Tim E.; Nielsen, J. Emil; Olesen, Arne V.

    2017-01-01

    into the long-wavelengths of the gravity estimates. This has made the stable-platform approach the preferred method for geodetic applications. In the summer of 2016, during a large airborne survey in Malaysia, a SIMU system was flown alongside a traditional LaCoste&Romberg (LCR) gravimeter. The SIMU......For the past two decades, airborne gravimetry using a Strapdown Inertial Measurement Unit (SIMU) has been producing gravity estimates comparable to the traditional stable-platform single-axis gravimeters. The challenge has been to control the long term drift of the IMU sensors, propagating...

  16. Upward continuation of Dome-C airborne gravity and comparison with GOCE gradients at orbit altitude in east Antarctica

    DEFF Research Database (Denmark)

    Yildiz, Hasan; Forsberg, René; Tscherning, Carl Christian

    2017-01-01

    spherical harmonic models confirmed the quality of the airborne data and that they contain more high-frequency signal than the global models. First, the airborne gravity data were upward continued to GOCE altitude to predict gravity gradients in the local North-East-Up reference frame. In this step...

  17. Marine Geoid Undulation Assessment Over South China Sea Using Global Geopotential Models and Airborne Gravity Data

    Science.gov (United States)

    Yazid, N. M.; Din, A. H. M.; Omar, K. M.; Som, Z. A. M.; Omar, A. H.; Yahaya, N. A. Z.; Tugi, A.

    2016-09-01

    Global geopotential models (GGMs) are vital in computing global geoid undulations heights. Based on the ellipsoidal height by Global Navigation Satellite System (GNSS) observations, the accurate orthometric height can be calculated by adding precise and accurate geoid undulations model information. However, GGMs also provide data from the satellite gravity missions such as GRACE, GOCE and CHAMP. Thus, this will assist to enhance the global geoid undulations data. A statistical assessment has been made between geoid undulations derived from 4 GGMs and the airborne gravity data provided by Department of Survey and Mapping Malaysia (DSMM). The goal of this study is the selection of the best possible GGM that best matches statistically with the geoid undulations of airborne gravity data under the Marine Geodetic Infrastructures in Malaysian Waters (MAGIC) Project over marine areas in Sabah. The correlation coefficients and the RMS value for the geoid undulations of GGM and airborne gravity data were computed. The correlation coefficients between EGM 2008 and airborne gravity data is 1 while RMS value is 0.1499.In this study, the RMS value of EGM 2008 is the lowest among the others. Regarding to the statistical analysis, it clearly represents that EGM 2008 is the best fit for marine geoid undulations throughout South China Sea.

  18. Airborne gravity survey of Lincoln Sea and Wandel Sea, north Greenland

    DEFF Research Database (Denmark)

    Olesen, Arne Vestergaard; Forsberg, René; Keller, K.

    2000-01-01

    In June 1998 National Survey and Cadastre Denmark (KMS) carried out an airborne gravity survey over the Polar Sea to the north of Greenland. A Twin Otter from Greenlandair, equipped with autopilot and additional fuel tanks, was employed for the survey. A modified marine LaCoste & Romberg gravimet...

  19. Downward continuation of airborne gravity data by means of the change of boundary approach

    Science.gov (United States)

    Mansi, A. H.; Capponi, M.; Sampietro, D.

    2018-03-01

    Within the modelling of gravity data, a common practice is the upward/downward continuation of the signal, i.e. the process of continuing the gravitational signal in the vertical direction away or closer to the sources, respectively. The gravity field, being a potential field, satisfies the Laplace's equation outside the masses and this means that it allows to unambiguously perform this analytical continuation only in a source-free domain. The analytical continuation problem has been solved both in the space and spectral domains by exploiting different algorithms. As well known, the downward continuation operator, differently from the upward one, is an unstable operator, due to its spectral characteristics similar to those of a high-pass filter, and several regularization methods have been proposed in order to stabilize it. In this work, an iterative procedure to downward/upward continue the gravity field observations, acquired at different altitudes, is proposed. This methodology is based on the change of boundary principle and it has been expressively thought for aerogravimetric observations for geophysical exploration purposes. Within this field of application, usually several simplifications can be applied, basically due to the specific characteristics of the airborne surveys which are usually flown at almost constant altitude as close as possible to the terrain. For instance, these characteristics, as shown in the present work, allow to perform the downward continuation without the need of any regularization. The goodness of the proposed methodology has been evaluated by means of a numerical test on real data, acquired in the South of Australia. The test shows that it is possible to move the aerogravimetric data, acquired along tracks with a maximum height difference of about 250 m, with accuracies of the order of 10^{-3} mGal.

  20. Far-zone contributions of airborne gravity anomalies' upward/downward continuation

    Directory of Open Access Journals (Sweden)

    Boyang Zhou

    2016-11-01

    Full Text Available Airborne gravimetry has become a vital technique in local gravity field approximation, and upward/downward continuation of gravity data is a key process of airborne gravimetry. In these procedures, the integral domain is divided into two parts, namely the near-zone and the far-zone. The far-zone contributions are approximated by the truncation coefficients and a global geo-potential model, and their values are controlled by several issues. This paper investigates the effects of flight height, the size of near-zone cap, and Remove-Compute-Restore (RCR technique upon far-zone contributions. Results show that at mountainous area the far-zone contributions can be ignored when EIGEN-6C of 360 degree is removed from the gravity data, together with a near-zone cap of 1° and a flight height less than 10 km, while at flat area EIGEN-6C of 180 degree is feasible.

  1. Using an Optionally Piloted Aircraft for Airborne Gravity Observations with the NOAA GRAV-D Project

    Science.gov (United States)

    Youngman, M.; Johnson, J. A.; van Westrum, D.; Damiani, T.

    2017-12-01

    The U.S. National Geodetic Survey's (NGS) Gravity for the Redefintion of the American Vertical Datum (GRAV-D) project is collecting airborne gravity data to support a 1 cm geoid. Started in 2008, this project will collect airborne gravity data over the entire U.S. and territories by 2022. As of June 30, 2017, the project was almost 62% complete. With recent technological developments, NGS has been exploring using unmanned aircraft for airborne gravity measurements. This presentation will focus on results from two surveys over the U.S. Appalachian and Rocky Mountains using the Aurora Centaur Optionally Piloted Aircraft and the Micro-g Lacoste Turnkey Airborne Gravimeter System 7 (TAGS7). Collecting high quality data as well as dealing with remote locations has been a challenge for the GRAV-D project and the field of airborne gravity in general. Unmanned aircraft could potentially improve data quality, handle hard to reach locations, and reduce pilot fatigue. The optionally piloted Centaur aircraft is an attractive option because it is not restricted in U.S. airspace and delivers high quality gravity data. Specifically, the Centaur meets U.S. Federal Aviation Administration regulations for Unmanned Aircraft Systems (UAS) by using a safety pilot on board to maintain line of sight and the ability to take control in the event of an emergency. Even though this is a sizeable UAS, most traditional gravimeters are too large and heavy for the platform. With a smaller and lighter design, the TAGS7 was used for its ability to conform to the aircraft's size restrictions, with the added benefit of upgraded performance capabilities. Two surveys were performed with this aircraft and gravimeter, one in April and one in August to September of 2017. Initial results indicate that the high-gain, fast response of the Centaur autopilot (optimized for flights without passengers), coupled with the full-force feedback sensor of the TAGS7, provides superior performance in all conditions, and

  2. Airborne Gravity: NGS' Gravity Data for the US and Territories (2008-2022) - National Geospatial Data Asset (NGDA) Airborne Gravity (GRAV-D)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gravity for the Re-definition of the American Vertical Datum (GRAV-D) is a project initiated by NOAA's National Geodetic Survey to collect and monitor gravity data...

  3. Testing Gravity Using Dwarf Stars

    OpenAIRE

    Sakstein, Jeremy

    2015-01-01

    Generic scalar-tensor theories of gravity predict deviations from Newtonian physics inside astrophysical bodies. In this paper, we point out that low mass stellar objects, red and brown dwarf stars, are excellent probes of these theories. We calculate two important and potentially observable quantities: the radius of brown dwarfs and the minimum mass for hydrogen burning in red dwarfs. The brown dwarf radius can differ significantly from the GR prediction and upcoming surveys that probe the m...

  4. Gravity changes in mid-west Greenland from GOCE gravity model and gradient data using ground and airborne gravity

    DEFF Research Database (Denmark)

    Tscherning, Carl Christian; Herceg, Matija; Fredenslund Levinsen, Joanna

    GOCE TRF (terrestrial reference frame) vertical anomalous gradients (Tzz) from two periods have been used to determine gravity anomalies changes in mid-west Greenland, where a large mass-loss has been detected using GRACE (Fig. 1). As additional data were used the GOCE DIR-3 model and ground...... gravity at the coast on solid rock, where no mass loss is expected. The methods of Least-Squares Collocation (LSC) and the Reduced Point Mass (RPM) methods have been used, however only LSC included the ground data....

  5. Testing quantum gravity through dumb holes

    Energy Technology Data Exchange (ETDEWEB)

    Pourhassan, Behnam, E-mail: b.pourhassan@du.ac.ir [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of); Faizal, Mir, E-mail: f2mir@uwaterloo.ca [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada); Irving K. Barber School of Arts and Sciences, University of British Columbia - Okanagan, Kelowna, BC V1V 1V7 (Canada); Capozziello, Salvatore, E-mail: capozzie@na.infn.it [Dipartimento di Fisica, Università di Napoli ”Frederico II” Complesso Universitario di Monte S. Angelo, Edificio G, Via Cinthia, I-80126 Napoli (Italy); Gran Sasso Science Institute (INFN), Via F. Crispi 7, I-67100 L’ Aquila (Italy)

    2017-02-15

    We propose a method to test the effects of quantum fluctuations on black holes by analyzing the effects of thermal fluctuations on dumb holes, the analogs for black holes. The proposal is based on the Jacobson formalism, where the Einstein field equations are viewed as thermodynamical relations, and so the quantum fluctuations are generated from the thermal fluctuations. It is well known that all approaches to quantum gravity generate logarithmic corrections to the entropy of a black hole and the coefficient of this term varies according to the different approaches to the quantum gravity. It is possible to demonstrate that such logarithmic terms are also generated from thermal fluctuations in dumb holes. In this paper, we claim that it is possible to experimentally test such corrections for dumb holes, and also obtain the correct coefficient for them. This fact can then be used to predict the effects of quantum fluctuations on realistic black holes, and so it can also be used, in principle, to experimentally test the different approaches to quantum gravity.

  6. [Development of a microenvironment test chamber for airborne microbe research].

    Science.gov (United States)

    Zhan, Ningbo; Chen, Feng; Du, Yaohua; Cheng, Zhi; Li, Chenyu; Wu, Jinlong; Wu, Taihu

    2017-10-01

    One of the most important environmental cleanliness indicators is airborne microbe. However, the particularity of clean operating environment and controlled experimental environment often leads to the limitation of the airborne microbe research. This paper designed and implemented a microenvironment test chamber for airborne microbe research in normal test conditions. Numerical simulation by Fluent showed that airborne microbes were evenly dispersed in the upper part of test chamber, and had a bottom-up concentration growth distribution. According to the simulation results, the verification experiment was carried out by selecting 5 sampling points in different space positions in the test chamber. Experimental results showed that average particle concentrations of all sampling points reached 10 7 counts/m 3 after 5 minutes' distributing of Staphylococcus aureus , and all sampling points showed the accordant mapping of concentration distribution. The concentration of airborne microbe in the upper chamber was slightly higher than that in the middle chamber, and that was also slightly higher than that in the bottom chamber. It is consistent with the results of numerical simulation, and it proves that the system can be well used for airborne microbe research.

  7. The Effect of Pitch, Roll, and Yaw on Airborne Gravity Observations of the NOAA GRAV-D Project

    Science.gov (United States)

    Childers, V. A.; Kanney, J.; Youngman, M.

    2017-12-01

    Aircraft turbulence can wreak havoc on the gravity measurementby beam-style gravimeters. Prior studies have confirmed the correlation of poor quality airborne gravity data collection to amplified aircraft motion. Motion in the aircraft is the combined effect of the airframe design, the autopilot and its performance, and the weather/wind regime. NOAA's National Geodetic Survey has launched the Gravity for the Redefinition of the American Vertical Datum project (GRAV-D) to provide the foundation for a new national vertical datum by 2022. This project requires collecting airborne gravity data covering the entire country and its holdings. The motion of the aircraft employed in this project is of prime importance because we use a beam-style gravimeter mounted on a gyro-stabilized platform to align the sensor to a time-averaged local vertical. Aircraft turbulence will tend to drive the platform off-level, allowing horizontal forces to map into the vertical gravity measurement. Recently, the GRAV-D project has experimented with two new factors in airborne gravity data collection. The first aspect is the use of the Aurora optionally piloted Centaur aircraft. This aircraft can be flown either with or without a pilot, but the autopilot is specifically designed to be very accurate. Incorporated into the much smaller frame of this aircraft is a new gravimeter developed by Micro-g LaCoste, called the Turnkey Airborne Gravimeter System 7 (TAGS7). This smaller, lighter instrument also has a new design whereby the beam is held fixed in an electromagnetic force field. The result of this new configuration is notably improved data quality in wind conditions higher than can be tolerated by our current system. So, which caused the improvement, the aircraft motion or the new meter? This study will start to tease apart these two effects with recently collected survey data. Specifically, we will compare the motion profile of the Centaur aircraft with other aircraft in the GRAV-D portfolio

  8. OPG nuclear - deaerator gravity flow test

    International Nuclear Information System (INIS)

    Davidge, E.; Sanchez, R.; Misra, A.; Vecchiarelli, J.

    2013-01-01

    Following a total loss of all AC power, preexisting SG and SGECS are consumed to maintain fuel cooling. These inventories last ~3.5 hours. Additional time is needed to establish offsite Emergency Mitigating Equipment (EME). EME are portable generators/pumps which pump screened lake water directly to boilers, moderator, HTS, vault, etc., as required. Deaerator storage tank inventory can provide water to SGs by gravity draining (additional ~5.5 hours). Deaerator and deaerator storage tank are the highest points in the feedwater system and are normally used to remove air and impurities from the secondary side and store demineralized water. Calculations were done to determine minimum flow requirements to steam generators in a Beyond Design Basis Accident (BDBA). Additional calculations were performed to determine how long deaerator water can achieve this minimum flow rate. A validation test was required to demonstrate that the required flow rates could be achieved, and interim heat sink could be established. Tests were performed on shut-down units during planned outages. Tests successfully demonstrated capability of the interim deaerator gravity drain heat sink. Tests results were very close to analytical predictions. As expected, actual flow rate was slightly higher than predicted since conservative assumptions were used.

  9. Testing chameleon gravity with the Coma cluster

    International Nuclear Information System (INIS)

    Terukina, Ayumu; Yamamoto, Kazuhiro; Lombriser, Lucas; Bacon, David; Koyama, Kazuya; Nichol, Robert C.

    2014-01-01

    We propose a novel method to test the gravitational interactions in the outskirts of galaxy clusters. When gravity is modified, this is typically accompanied by the introduction of an additional scalar degree of freedom, which mediates an attractive fifth force. The presence of an extra gravitational coupling, however, is tightly constrained by local measurements. In chameleon modifications of gravity, local tests can be evaded by employing a screening mechanism that suppresses the fifth force in dense environments. While the chameleon field may be screened in the interior of the cluster, its outer region can still be affected by the extra force, introducing a deviation between the hydrostatic and lensing mass of the cluster. Thus, the chameleon modification can be tested by combining the gas and lensing measurements of the cluster. We demonstrate the operability of our method with the Coma cluster, for which both a lensing measurement and gas observations from the X-ray surface brightness, the X-ray temperature, and the Sunyaev-Zel'dovich effect are available. Using the joint observational data set, we perform a Markov chain Monte Carlo analysis of the parameter space describing the different profiles in both the Newtonian and chameleon scenarios. We report competitive constraints on the chameleon field amplitude and its coupling strength to matter. In the case of f(R) gravity, corresponding to a specific choice of the coupling, we find an upper bound on the background field amplitude of |f R0 | < 6 × 10 −5 , which is currently the tightest constraint on cosmological scales

  10. Testing chameleon gravity with the Coma cluster

    Energy Technology Data Exchange (ETDEWEB)

    Terukina, Ayumu; Yamamoto, Kazuhiro [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Kagamiyama 1-3-1, 739-8526 (Japan); Lombriser, Lucas; Bacon, David; Koyama, Kazuya; Nichol, Robert C., E-mail: telkina@theo.phys.sci.hiroshima-u.ac.jp, E-mail: lucas.lombriser@port.ac.uk, E-mail: kazuhiro@hiroshima-u.ac.jp, E-mail: david.bacon@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk, E-mail: bob.nichol@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom)

    2014-04-01

    We propose a novel method to test the gravitational interactions in the outskirts of galaxy clusters. When gravity is modified, this is typically accompanied by the introduction of an additional scalar degree of freedom, which mediates an attractive fifth force. The presence of an extra gravitational coupling, however, is tightly constrained by local measurements. In chameleon modifications of gravity, local tests can be evaded by employing a screening mechanism that suppresses the fifth force in dense environments. While the chameleon field may be screened in the interior of the cluster, its outer region can still be affected by the extra force, introducing a deviation between the hydrostatic and lensing mass of the cluster. Thus, the chameleon modification can be tested by combining the gas and lensing measurements of the cluster. We demonstrate the operability of our method with the Coma cluster, for which both a lensing measurement and gas observations from the X-ray surface brightness, the X-ray temperature, and the Sunyaev-Zel'dovich effect are available. Using the joint observational data set, we perform a Markov chain Monte Carlo analysis of the parameter space describing the different profiles in both the Newtonian and chameleon scenarios. We report competitive constraints on the chameleon field amplitude and its coupling strength to matter. In the case of f(R) gravity, corresponding to a specific choice of the coupling, we find an upper bound on the background field amplitude of |f{sub R0}| < 6 × 10{sup −5}, which is currently the tightest constraint on cosmological scales.

  11. A flight test of the strapdown airborne gravimeter SGA-WZ in Greenland

    DEFF Research Database (Denmark)

    Zhao, Lei; Forsberg, René; Wu, Meiping

    2015-01-01

    -WZ strapdown airborne gravimeter in Greenland, in an area with good gravity coverage from earlier marine and airborne surveys. An overview of this new system SGA-WZ is given, including system design, sensor performance and data processing. The processing of the SGA-WZ includes a 160 s length finite impulse...

  12. Testing Einstein's Gravity on Large Scales

    Science.gov (United States)

    Prescod-Weinstein, Chandra

    2011-01-01

    A little over a decade has passed since two teams studying high redshift Type Ia supernovae announced the discovery that the expansion of the universe was accelerating. After all this time, we?re still not sure how cosmic acceleration fits into the theory that tells us about the large-scale universe: General Relativity (GR). As part of our search for answers, we have been forced to question GR itself. But how will we test our ideas? We are fortunate enough to be entering the era of precision cosmology, where the standard model of gravity can be subjected to more rigorous testing. Various techniques will be employed over the next decade or two in the effort to better understand cosmic acceleration and the theory behind it. In this talk, I will describe cosmic acceleration, current proposals to explain it, and weak gravitational lensing, an observational effect that allows us to do the necessary precision cosmology.

  13. Crustal structure beneath the Paleozoic Parnaíba Basin revealed by airborne gravity and magnetic data, Brazil

    Science.gov (United States)

    de Castroa, David L.; Fuck, Reinhardt A.; Phillips, Jeffrey D.; Vidotti, Roberta M.; Bezerra, Francisco H. R.; Dantas, Elton L.

    2014-01-01

    The Parnaíba Basin is a large Paleozoic syneclise in northeastern Brazil underlain by Precambrian crystalline basement, which comprises a complex lithostructural and tectonic framework formed during the Neoproterozoic–Eopaleozoic Brasiliano–Pan African orogenic collage. A sag basin up to 3.5 km thick and 1000 km long formed after the collage. The lithologic composition, structure, and role in the basin evolution of the underlying basement are the focus of this study. Airborne gravity and magnetic data were modeled to reveal the general crustal structure underneath the Parnaíba Basin. Results indicate that gravity and magnetic signatures delineate the main boundaries and structural trends of three cratonic areas and surrounding Neoproterozoic fold belts in the basement. Triangular-shaped basement inliers are geophysically defined in the central region of this continental-scale Neoproterozoic convergence zone. A 3-D gravity inversion constrained by seismological data reveals that basement inliers exhibit a 36–40.5 km deep crustal root, with borders defined by a high-density and thinner crust. Forward modeling of gravity and magnetic data indicates that lateral boundaries between crustal units are limited by Brasiliano shear zones, representing lithospheric sutures of the Amazonian and São Francisco Cratons, Tocantins Province and Parnaíba Block. In addition, coincident residual gravity, residual magnetic, and pseudo-gravity lows indicate two complex systems of Eopaleozoic rifts related to the initial phase of the sag deposition, which follow basement trends in several directions.

  14. STELLAR STRUCTURE AND TESTS OF MODIFIED GRAVITY

    International Nuclear Information System (INIS)

    Chang, Philip; Hui, Lam

    2011-01-01

    Theories that attempt to explain cosmic acceleration by modifying gravity typically introduces a long-range scalar force that needs to be screened on small scales. One common screening mechanism is the chameleon, where the scalar force is screened in environments with a sufficiently deep gravitational potential, but acts unimpeded in regions with a shallow gravitational potential. This leads to a variation in the overall gravitational G with environment. We show that such a variation can occur within a star itself, significantly affecting its evolution and structure, provided that the host galaxy is unscreened. The effect is most pronounced for red giants, which would be smaller by a factor of tens of percent and thus hotter by hundreds of Kelvin, depending on the parameters of the underlying scalar-tensor theory. Careful measurements of these stars in suitable environments (nearby dwarf galaxies not associated with groups or clusters) would provide constraints on the chameleon mechanism that are four orders of magnitude better than current large-scale structure limits and two orders of magnitude better than present solar system tests.

  15. Integrated Automatic Test System for Airborne Optoelectronic Pods

    International Nuclear Information System (INIS)

    Zhang, Z M; Ding, M J; Wang, L

    2006-01-01

    Based on the introduction of the construction and basic principle of the airborne optoelectronic pod, in accordance with the performance standards of the pod, the total solution scheme of the automatic test system used for testing the combination property is proposed in this paper. The main structure, hardware and software design of the system based on the virtual instruments technology are also discussed in detail. The result of the true run proves the practicality, efficiency, high accuracy and other characteristics of the computer aided testing system based on virtual instruments

  16. Testing a Dilaton Gravity Model Using Nucleosynthesis

    International Nuclear Information System (INIS)

    Boran, S.; Kahya, E. O.

    2014-01-01

    Big bang nucleosynthesis (BBN) offers one of the most strict evidences for the Λ-CDM cosmology at present, as well as the cosmic microwave background (CMB) radiation. In this work, our main aim is to present the outcomes of our calculations related to primordial abundances of light elements, in the context of higher dimensional steady-state universe model in the dilaton gravity. Our results show that abundances of light elements (primordial D, 3 He, 4 He, T, and 7 Li) are significantly different for some cases, and a comparison is given between a particular dilaton gravity model and Λ-CDM in the light of the astrophysical observations

  17. Putting the Scanning Laser Environmental Airborne Fluorosensor through its paces : initial test results

    International Nuclear Information System (INIS)

    Brown, C.E.; Fingas, M.F.; Mullin, J.V.; Dick, R.; Giroud, C.

    1998-01-01

    The development and construction of a remote sensing system used to detect and map oil and related petroleum products in complex marine and shoreline environments was reviewed. The Scanning Laser Environmental Airborne Fluorosensor (SLEAF) system will be integrated into Environment Canada's DC-3 aircraft and will be undergoing extensive testing to verify its functionality in an airborne environment. Laser fluorosensors are the only sensors that can successfully detect oil in most environments including snow and ice. One of the roles of SLEAF will be to confirm or reject suspected oil contamination sites that have been targeted by infrared or visible spectral cameras. The ability of the SLEAF system to detect, classify and estimate oil coverage has been tested using a total of twenty-one oils ranging from light refined crude through to heavy refined oils. The aromatic content of the oils varied between 13 and 52 per cent and the API gravities of the oils tested varied from 11.9 to 48.6. 10 refs., 2 tabs., 2 figs

  18. Laboratory experiments to test relativistic gravity

    International Nuclear Information System (INIS)

    Braginsky, V.B.; Caves, C.M.; Thorne, K.S.

    1977-01-01

    Advancing technology will soon make possible a new class of gravitation experiments: pure laboratory experiments with laboratory sources of non-Newtonian gravity and laboratory detectors. This paper proposes seven such experiments; and for each one it describes, briefly, the dominant sources of noise and the technology required. Three experiments would utilize a high-Q torque balance as the detector. They include (i) an ''Ampere-type'' experiment to measure the gravitational spin-spin coupling of two rotating bodies, (ii) a search for time changes of the gravitation constant, and (iii) a measurement of the gravity produced by magnetic stresses and energy. Three experiments would utilize a high-Q dielectric crystal as the detector. They include (i) a ''Faraday-type'' experiment to measure the ''electric-type'' gravity produced by a time-changing flux of ''magnetic-type'' gravity, (ii) a search for ''preferred-frame'' and ''preferred-orientation'' effects in gravitational coupling, and (iii) a measurement of the gravitational field produced by protons moving in a storage ring at nearly the speed of light. One experiment would use a high-Q toroidal microwave cavity as detector to search for the dragging of inertial frames by a rotating body

  19. Superconducting gravity gradiometer and a test of inverse square law

    International Nuclear Information System (INIS)

    Moody, M.V.; Paik, H.J.

    1989-01-01

    The equivalence principle prohibits the distinction of gravity from acceleration by a local measurement. However, by making a differential measurement of acceleration over a baseline, platform accelerations can be cancelled and gravity gradients detected. In an in-line superconducting gravity gradiometer, this differencing is accomplished with two spring-mass accelerometers in which the proof masses are confined to motion in a single degree of freedom and are coupled together by superconducting circuits. Platform motions appear as common mode accelerations and are cancelled by adjusting the ratio of two persistent currents in the sensing circuit. The sensing circuit is connected to a commercial SQUID amplifier to sense changes in the persistent currents generated by differential accelerations, i.e., gravity gradients. A three-axis gravity gradiometer is formed by mounting six accelerometers on the faces of a precision cube, with the accelerometers on opposite faces of the cube forming one of three in-line gradiometers. A dedicated satellite mission for mapping the earth's gravity field is an important one. Additional scientific goals are a test of the inverse square law to a part in 10(exp 10) at 100 km, and a test of the Lense-Thirring effect by detecting the relativistic gravity magnetic terms in the gravity gradient tensor for the earth

  20. Hardware Design for a Fixed-Wing Airborne Gravity Measurement System

    Science.gov (United States)

    1986-12-22

    worldwide navigation system currently available that is sufficiently accurate for deter- mining Eotvos correction in airborne gravimetry is the Global...better in defining the strength of precipitation . The radar display is compact enough to be mounted on the cockpit, thus giving the pilots better...of the proposed AGMS version 3 MISCELLANEOUS AIRCRAFT CONSIDERATIONS Autopilot One of the most important considerations in airborne gravimetry is

  1. Thermosyphon Flooding in Reduced Gravity Environments Test Results

    Science.gov (United States)

    Gibson, Marc A.; Jaworske, Donald A.; Sanzi, Jim; Ljubanovic, Damir

    2013-01-01

    The condenser flooding phenomenon associated with gravity aided two-phase thermosyphons was studied using parabolic flights to obtain the desired reduced gravity environment (RGE). The experiment was designed and built to test a total of twelve titanium water thermosyphons in multiple gravity environments with the goal of developing a model that would accurately explain the correlation between gravitational forces and the maximum axial heat transfer limit associated with condenser flooding. Results from laboratory testing and parabolic flights are included in this report as part I of a two part series. The data analysis and correlations are included in a follow on paper.

  2. Characterization of airborne uranium from test firing of XM774 ammunition

    International Nuclear Information System (INIS)

    Glissmeyer, J.A.; Mishima, J.

    1979-11-01

    Pacific Northwest Laboratory conducted experiments at Aberdeen Proving Grounds, Maryland, to characterize the airborne depleted uranium (DU) resulting from the test firings of 105-mm, APFSDS-T XM774 ammunition. The goal was to obtain data pertinent to evaluations of human inhalation exposure to the airborne DU. Data was desired concerning the following: (1) size distribution of airborne DU; (2) quantity of airborne DU; (3) dispersion of airborne DU from the target vicinity; (4) amount of DU deposited on the ground; (5) solubility of airborne DU compounds in lung fluid; and (6) oxide forms of airborne and fallout DU. The experiments involved extensive air sampling for total airborne DU particulates and respirable DU particles both above the targets and at distances downwind. Fallout and fragments were collected around the target area. High-speed movies of the smoke generated from the impact of the penetrators were taken to estimate the cloud volumes. Results of the experiments are presented

  3. statistical tests for frequency distribution of mean gravity anomalies

    African Journals Online (AJOL)

    ES Obe

    1980-03-01

    Mar 1, 1980 ... STATISTICAL TESTS FOR FREQUENCY DISTRIBUTION OF MEAN. GRAVITY ANOMALIES. By ... approach. Kaula [1,2] discussed the method of applying statistical techniques in the ..... mathematical foundation of physical ...

  4. Tests and comparisons of gravity models.

    Science.gov (United States)

    Marsh, J. G.; Douglas, B. C.

    1971-01-01

    Optical observations of the GEOS satellites were used to obtain orbital solutions with different sets of geopotential coefficients. The solutions were compared before and after modification to high order terms (necessary because of resonance) and were then analyzed by comparing subsequent observations with predicted trajectories. The most important source of error in orbit determination and prediction for the GEOS satellites is the effect of resonance found in most published sets of geopotential coefficients. Modifications to the sets yield greatly improved orbits in most cases. The results of these comparisons suggest that with the best optical tracking systems and gravity models, satellite position error due to gravity model uncertainty can reach 50-100 m during a heavily observed 5-6 day orbital arc. If resonant coefficients are estimated, the uncertainty is reduced considerably.

  5. Testing the weak gravity-cosmic censorship connection

    Science.gov (United States)

    Crisford, Toby; Horowitz, Gary T.; Santos, Jorge E.

    2018-03-01

    A surprising connection between the weak gravity conjecture and cosmic censorship has recently been proposed. In particular, it was argued that a promising class of counterexamples to cosmic censorship in four-dimensional Einstein-Maxwell-Λ theory would be removed if charged particles (with sufficient charge) were present. We test this idea and find that indeed if the weak gravity conjecture is true, one cannot violate cosmic censorship this way. Remarkably, the minimum value of charge required to preserve cosmic censorship appears to agree precisely with that proposed by the weak gravity conjecture.

  6. Theoretical frameworks for testing relativistic gravity: A review

    Science.gov (United States)

    Thorne, K. S.; Will, C. M.; Ni, W.

    1971-01-01

    Metric theories of gravity are presented, including the definition of metric theory, evidence for its existence, and response of matter to gravity with test body trajectories, gravitational red shift, and stressed matter responses. Parametrized post-Newtonian framework and interpretations are reviewed. Gamma, beta and gamma, and varied other parameters were measured. Deflection of electromagnetic waves, radar time delay, geodetic gyroscope precession, perihelion shifts, and periodic effects in orbits are among various studies carried out for metric theory experimentation.

  7. Airborne Turbulence Detection and Warning ACLAIM Flight Test Results

    Science.gov (United States)

    Hannon, Stephen M.; Bagley, Hal R.; Soreide, Dave C.; Bowdle, David A.; Bogue, Rodney K.; Ehernberger, L. Jack

    1999-01-01

    The Airborne Coherent Lidar for Advanced Inflight Measurements (ACLAIM) is a NASA/Dryden-lead program to develop and demonstrate a 2 micrometers pulsed Doppler lidar for airborne look-ahead turbulence detection and warning. Advanced warning of approaching turbulence can significantly reduce injuries to passengers and crew aboard commercial airliners. The ACLAIM instrument is a key asset to the ongoing Turbulence component of NASA's Aviation Safety Program, aimed at reducing the accident rate aboard commercial airliners by a factor of five over the next ten years and by a factor of ten over the next twenty years. As well, the advanced turbulence warning capability can prevent "unstarts" in the inlet of supersonic aircraft engines by alerting the flight control computer which then adjusts the engine to operate in a less fuel efficient, and more turbulence tolerant, mode. Initial flight tests of the ACLAIM were completed in March and April of 1998. This paper and presentation gives results from these initial flights, with validated demonstration of Doppler lidar wind turbulence detection several kilometers ahead of the aircraft.

  8. Preliminary testing of the Scanning Laser Environmental Airborne Fluorosensor

    International Nuclear Information System (INIS)

    Brown, C.E.; Marois, R.; Fingas, M.F.; Mullin, J.V.

    2000-01-01

    The installation and testing program of the Scanning Laser Environmental Airborne Fluorosensor (SLEAF) on Environment Canada's DC-3 aircraft was described and the capabilities of the new system were presented. SLEAF is a new generation of laser fluorosensor designed to provide prompt reliable detection and mapping of oil pollution in different marine and terrestrial environments. It consists of a high-power excimer laser, high-resolution range-gated intensified diode-array spectrometer, and a pair of variable speed and angular displacement scanning mirrors. SLEAF is capable of detecting narrow bands of oil that can pile up along the high tide lines of beaches and shorelines, including those that contain ice and snow. It also has the added benefit of providing real-time detection. SLEAF will be declared operational for emergency response personnel when the initial test flight program will be completed in the near future. 9 refs., 2 figs

  9. Sensor integration and testing in an airborne environment

    Science.gov (United States)

    Ricks, Timothy P.; Streling, Julie T.; Williams, Kirk W.

    2005-11-01

    The U.S. Army Redstone Technical Test Center (RTTC) has been supporting captive flight testing of missile sensors and seekers since the 1980's. Successful integration and test of sensors in an airborne environment requires attention to a broad range of disciplines. Data collection requirements drive instrumentation and flight profile configurations, which along with cost and airframe performance factors influence the choice of test aircraft. Installation methods used for instrumentation must take into consideration environmental and airworthiness factors. In addition, integration of test equipment into the aircraft will require an airworthiness release; procedures vary between the government for military aircraft, and the Federal Aviation Administration (FAA) for the use of private, commercial, or experimental aircraft. Sensor mounting methods will depend on the type of sensor being used, both for sensor performance and crew safety concerns. Pilots will require navigation input to permit the execution of accurate and repeatable flight profiles. Some tests may require profiles that are not supported by standard navigation displays, requiring the use of custom hardware/software. Test locations must also be considered in their effect on successful data collection. Restricted airspace may also be required, depending on sensor emissions and flight profiles.

  10. Black holes a laboratory for testing strong gravity

    CERN Document Server

    Bambi, Cosimo

    2017-01-01

    This textbook introduces the current astrophysical observations of black holes, and discusses the leading techniques to study the strong gravity region around these objects with electromagnetic radiation. More importantly, it provides the basic tools for writing an astrophysical code and testing the Kerr paradigm. Astrophysical black holes are an ideal laboratory for testing strong gravity. According to general relativity, the spacetime geometry around these objects should be well described by the Kerr solution. The electromagnetic radiation emitted by the gas in the inner part of the accretion disk can probe the metric of the strong gravity region and test the Kerr black hole hypothesis. With exercises and examples in each chapter, as well as calculations and analytical details in the appendix, the book is especially useful to the beginners or graduate students who are familiar with general relativity while they do not have any background in astronomy or astrophysics.

  11. Geoid Model and Altitude at Mount Aconcagua Region (Argentina) from Airborne Gravity Survey

    DEFF Research Database (Denmark)

    Cristina Pacino, M.; Jaeger, Eric; Forsberg, René

    2014-01-01

    Aconcagua is part of the Southern Andes in the Argentine Province of Mendoza and it is the highest mountain in the Americas. The Aconcagua region is mostly inaccessible for land surveys. The existing gravity data are sparsely distributed, and mainly along the route currently used to climb the mou...

  12. Statistical Tests for Frequency Distribution of Mean Gravity Anomalies

    African Journals Online (AJOL)

    The hypothesis that a very large number of lOx 10mean gravity anomalies are normally distributed has been rejected at 5% Significance level based on the X2 and the unit normal deviate tests. However, the 50 equal area mean anomalies derived from the lOx 10data, have been found to be normally distributed at the same ...

  13. Planck-scale gravity test at PETRA. Letter of intent

    Energy Technology Data Exchange (ETDEWEB)

    Gharibyan, V.; Balewski, K.

    2016-02-15

    Quantum or torsion gravity models predict unusual properties of space- time at very short distances. In particular, near the Planck length, around 10{sup -35} m, empty space may behave as a crystal, singly or doubly refractive. This hypothesis, however, remains uncheckable for any direct measurement since the smallest distance accessible in experiment is about 10{sup -19} m at the LHC. Here we propose a laboratory test to measure space birefringence or refractivity induced by gravity. A sensitivity 10{sup -31} m for doubly and 10{sup -28} m for singly refractive vacuum could be reached with PETRA 6 GeV beam exploring UV laser Compton scattering.

  14. Planck-scale gravity test at PETRA. Letter of intent

    International Nuclear Information System (INIS)

    Gharibyan, V.; Balewski, K.

    2016-02-01

    Quantum or torsion gravity models predict unusual properties of space- time at very short distances. In particular, near the Planck length, around 10 -35 m, empty space may behave as a crystal, singly or doubly refractive. This hypothesis, however, remains uncheckable for any direct measurement since the smallest distance accessible in experiment is about 10 -19 m at the LHC. Here we propose a laboratory test to measure space birefringence or refractivity induced by gravity. A sensitivity 10 -31 m for doubly and 10 -28 m for singly refractive vacuum could be reached with PETRA 6 GeV beam exploring UV laser Compton scattering.

  15. Testing gravity with EG: mapping theory onto observations

    Science.gov (United States)

    Leonard, C. Danielle; Ferreira, Pedro G.; Heymans, Catherine

    2015-12-01

    We present a complete derivation of the observationally motivated definition of the modified gravity statistic EG. Using this expression, we investigate how variations to theory and survey parameters may introduce uncertainty in the general relativistic prediction of EG. We forecast errors on EG for measurements using two combinations of upcoming surveys, and find that theoretical uncertainties may dominate for a futuristic measurement. Finally, we compute predictions of EG under modifications to general relativity in the quasistatic regime, and comment on the pros and cons of using EG to test gravity with future surveys.

  16. Unraveling gravity beyond Einstein with extended test bodies

    International Nuclear Information System (INIS)

    Puetzfeld, Dirk; Obukhov, Yuri N.

    2013-01-01

    The motion of test bodies in gravity is tightly linked to the conservation laws. This well-known fact in the context of General Relativity is also valid for gravitational theories which go beyond Einstein's theory. Here we derive the equations of motion for test bodies for a very large class of gravitational theories with a general nonminimal coupling to matter. These equations form the basis for future systematic tests of alternative gravity theories. Our treatment is covariant and generalizes the classic Mathisson–Papapetrou–Dixon result for spinning (extended) test bodies. The equations of motion for structureless test bodies turn out to be surprisingly simple, despite the very general nature of the theories considered.

  17. GLM Post Launch Testing and Airborne Science Field Campaign

    Science.gov (United States)

    Goodman, S. J.; Padula, F.; Koshak, W. J.; Blakeslee, R. J.

    2017-12-01

    The Geostationary Operational Environmental Satellite (GOES-R) series provides the continuity for the existing GOES system currently operating over the Western Hemisphere. The Geostationary Lightning Mapper (GLM) is a wholly new instrument that provides a capability for total lightning detection (cloud and cloud-to-ground flashes). The first satellite in the GOES-R series, now GOES-16, was launched in November 2016 followed by in-orbit post launch testing for approximately 12 months before being placed into operations replacing the GOES-E satellite in December. The GLM will map total lightning continuously throughout day and night with near-uniform spatial resolution of 8 km with a product latency of less than 20 sec over the Americas and adjacent oceanic regions. The total lightning is very useful for identifying hazardous and severe thunderstorms, monitoring storm intensification and tracking evolution. Used in tandem with radar, satellite imagery, and surface observations, total lightning data has great potential to increase lead time for severe storm warnings, improve aviation safety and efficiency, and increase public safety. In this paper we present initial results from the post-launch in-orbit performance testing, airborne science field campaign conducted March-May, 2017 and assessments of the GLM instrument and science products.

  18. Test field for airborne laser scanning in Finland

    Science.gov (United States)

    Ahokas, E.; Kaartinen, H.; Kukko, A.; Litkey, P.

    2014-11-01

    Airborne laser scanning (ALS) is a widely spread operational measurement tool for obtaining 3D coordinates of the ground surface. There is a need for calibrating the ALS system and a test field for ALS was established at the end of 2013. The test field is situated in the city of Lahti, about 100 km to the north of Helsinki. The size of the area is approximately 3.5 km × 3.2 km. Reference data was collected with a mobile laser scanning (MLS) system assembled on a car roof. Some streets were measured both ways and most of them in one driving direction only. The MLS system of the Finnish Geodetic Institute (FGI) consists of a navigation system (NovAtel SPAN GNSS-IMU) and a laser scanner (FARO Focus3D 120). In addition to the MLS measurements more than 800 reference points were measured using a Trimble R8 VRS-GNSS system. Reference points are along the streets, on parking lots, and white pedestrian crossing line corners which can be used as reference targets. The National Land Survey of Finland has already used this test field this spring for calibrating their Leica ALS-70 scanner. Especially it was easier to determine the encoder scale factor parameter using this test field. Accuracy analysis of the MLS points showed that the point height RMSE is 2.8 cm and standard deviation is 2.6 cm. Our purpose is to measure both more MLS data and more reference points in the test field area to get a better spatial coverage. Calibration flight heights are planned to be 1000 m and 2500 m above ground level. A cross pattern, southwest-northeast and northwest-southeast, will be flown both in opposite directions.

  19. Tests of Gravity Using Lunar Laser Ranging

    Directory of Open Access Journals (Sweden)

    Stephen M. Merkowitz

    2010-11-01

    Full Text Available Lunar laser ranging (LLR has been a workhorse for testing general relativity over the past four decades. The three retroreflector arrays put on the Moon by the Apollo astronauts and the French built arrays on the Soviet Lunokhod rovers continue to be useful targets, and have provided the most stringent tests of the Strong Equivalence Principle and the time variation of Newton’s gravitational constant. The relatively new ranging system at the Apache Point 3.5 meter telescope now routinely makes millimeter level range measurements. Incredibly, it has taken 40 years for ground station technology to advance to the point where characteristics of the lunar retroreflectors are limiting the precision of the range measurements. In this article, we review the gravitational science and technology of lunar laser ranging and discuss prospects for the future.

  20. Cosmological consistency tests of gravity theory and cosmic acceleration

    Science.gov (United States)

    Ishak-Boushaki, Mustapha B.

    2017-01-01

    Testing general relativity at cosmological scales and probing the cause of cosmic acceleration are among the important objectives targeted by incoming and future astronomical surveys and experiments. I present our recent results on consistency tests that can provide insights about the underlying gravity theory and cosmic acceleration using cosmological data sets. We use statistical measures, the rate of cosmic expansion, the growth rate of large scale structure, and the physical consistency of these probes with one another.

  1. Gravity

    CERN Document Server

    Gamow, George

    2003-01-01

    A distinguished physicist and teacher, George Gamow also possessed a special gift for making the intricacies of science accessible to a wide audience. In Gravity, he takes an enlightening look at three of the towering figures of science who unlocked many of the mysteries behind the laws of physics: Galileo, the first to take a close look at the process of free and restricted fall; Newton, originator of the concept of gravity as a universal force; and Einstein, who proposed that gravity is no more than the curvature of the four-dimensional space-time continuum.Graced with the author's own draw

  2. Frameworks for analyzing and testing theories of gravity

    International Nuclear Information System (INIS)

    Lee, D.L.

    1974-01-01

    Theoretical frameworks are presented for the analysis and testing of gravitation theories--both metric and nonmetric. For nonmetric theories, the high precision Eotvos--Dicke--Braginskii (EBD) experiments are demonstrated to be powerful tests of their gravitational coupling to electromagnetic interactions. All known nonmetric theories are ruled out to within the precision of the EDB experiments. A new metric theory of gravity is presented that cannot be distinguished from general relativity in all current and planned solar system experiments. However, this theory has very different gravitational-wave properties. Hence, the need for further tests of metric theories beyond the Parametrized Post--Newtonian formalism is pointed out and the importance of the observation of gravitational waves as a tool for testing relativistic gravity in the future is emphasized. A theory-independent formalism delineating the properties of weak, plane gravitational waves in metric theories is set up. General conservation laws that follow from variational principles in metric theories of gravity are investigated. (U.S.)

  3. Sensitive Superconducting Gravity Gradiometer Constructed with Levitated Test Masses

    Science.gov (United States)

    Griggs, C. E.; Moody, M. V.; Norton, R. S.; Paik, H. J.; Venkateswara, K.

    2017-12-01

    We demonstrate basic operations of a two-component superconducting gravity gradiometer (SGG) that is constructed with a pair of magnetically levitated test masses coupled to superconducting quantum-interference devices. A design that gives a potential sensitivity of 1.4 ×10-4 E Hz-1 /2 (1 E ≡10-9 s-2 ) in the frequency band of 1 to 50 mHz and better than 2 ×10-5 E Hz-1 /2 between 0.1 and 1 mHz for a compact tensor SGG that fits within a 22-cm-diameter sphere. The SGG has the capability of rejecting the platform acceleration and jitter in all 6 degrees of freedom to one part in 109 . Such an instrument has applications in precision tests of fundamental laws of physics, earthquake early warning, and gravity mapping of Earth and the planets.

  4. Pulsar timing arrays and gravity tests in the radiative regime

    Science.gov (United States)

    Lee, K. J.

    2013-11-01

    In this paper, we focus on testing gravity theories in the radiative regime using pulsar timing array observations. After reviewing current techniques to measure the dispersion and alternative polarization of gravitational waves, we extend the framework to the most general situations, where the combinations of a massive graviton and alternative polarization modes are considered. The atlas of the Hellings-Downs functions is completed by the new calculations for these dispersive alternative polarization modes. We find that each mode and corresponding graviton mass introduce characteristic features in the Hellings-Downs function. Thus, in principal, we can not only detect each polarization mode, measure the corresponding graviton mass, but also discriminate the different scenarios. In this way, we can test gravity theories in the radiative regime in a generalized fashion, and such method is a direct experiment, where one can address the gauge symmetry of the gravity theories in their linearized limits. Although current pulsar timing still lacks enough stable pulsars and sensitivity for such practices, we expect that future telescopes with larger collecting areas could make such experiments feasible.

  5. Testing Quantum Gravity Induced Nonlocality via Optomechanical Quantum Oscillators.

    Science.gov (United States)

    Belenchia, Alessio; Benincasa, Dionigi M T; Liberati, Stefano; Marin, Francesco; Marino, Francesco; Ortolan, Antonello

    2016-04-22

    Several quantum gravity scenarios lead to physics below the Planck scale characterized by nonlocal, Lorentz invariant equations of motion. We show that such nonlocal effective field theories lead to a modified Schrödinger evolution in the nonrelativistic limit. In particular, the nonlocal evolution of optomechanical quantum oscillators is characterized by a spontaneous periodic squeezing that cannot be generated by environmental effects. We discuss constraints on the nonlocality obtained by past experiments, and show how future experiments (already under construction) will either see such effects or otherwise cast severe bounds on the nonlocality scale (well beyond the current limits set by the Large Hadron Collider). This paves the way for table top, high precision experiments on massive quantum objects as a promising new avenue for testing some quantum gravity phenomenology.

  6. Testing Modified Gravity Theories via Wide Binaries and GAIA

    Science.gov (United States)

    Pittordis, Charalambos; Sutherland, Will

    2018-06-01

    The standard ΛCDM model based on General Relativity (GR) including cold dark matter (CDM) is very successful at fitting cosmological observations, but recent non-detections of candidate dark matter (DM) particles mean that various modified-gravity theories remain of significant interest. The latter generally involve modifications to GR below a critical acceleration scale ˜10-10 m s-2. Wide-binary (WB) star systems with separations ≳ 5 kAU provide an interesting test for modified gravity, due to being in or near the low-acceleration regime and presumably containing negligible DM. Here, we explore the prospects for new observations pending from the GAIA spacecraft to provide tests of GR against MOND or TeVes-like theories in a regime only partially explored to date. In particular, we find that a histogram of (3D) binary relative velocities, relative to equilibrium circular velocity predicted from the (2D) projected separation predicts a rather sharp feature in this distribution for standard gravity, with an 80th (90th) percentile value close to 1.025 (1.14) with rather weak dependence on the eccentricity distribution. However, MOND/TeVeS theories produce a shifted distribution, with a significant increase in these upper percentiles. In MOND-like theories without an external field effect, there are large shifts of order unity. With the external field effect included, the shifts are considerably reduced to ˜0.04 - 0.08, but are still potentially detectable statistically given reasonably large samples and good control of contaminants. In principle, followup of GAIA-selected wide binaries with ground-based radial velocities accurate to ≲ 0.03 { km s^{-1}} should be able to produce an interesting new constraint on modified-gravity theories.

  7. Development of new test procedures for measuring fine and coarse aggregates specific gravity.

    Science.gov (United States)

    2009-09-01

    The objective of the research is to develop and evaluate new test methods at determining the specific gravity and absorption of both fine and coarse aggregates. Current methods at determining the specific gravity and absorption of fine and coarse agg...

  8. Testing Gravity via Lunar Laser Ranging: Maximizing Data Quality

    Science.gov (United States)

    Murphy, Thomas

    We propose to continue leading-edge observations with the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO), in an effort to subject gravity to the most stringent tests yet. APOLLO has delivered a dramatic improvement in the measurement of the lunar orbit: now at the millimeter level. Yet incomplete models are thus far unable to confirm the accuracy. We therefore seek to build a calibration system to ensure that APOLLO meets its millimeter measurement goal. Gravity--the most evident force of nature--is in fact the weakest of the fundamental forces, and consequently the most poorly tested. Einstein’s general relativity, which is currently our best description of gravity, is fundamentally incompatible with quantum mechanics and is likely to be replaced by a more complete theory in the future. A modified theory would predict small deviations in the solar system that could have profound consequences for our understanding of the Universe as a whole. Lunar laser ranging (LLR), in which short laser pulses launched from a telescope are bounced off of reflectors placed on the Moon by U.S. astronauts and Soviet landers, has for decades produced some of the leading tests of gravity by mapping the shape of the lunar orbit to high precision. These include tests of the strong equivalence principle, the time-rate-ofchange of Newton’s gravitational constant, gravitomagnetism, the inverse-square law, and many others. Among the attributes that contribute to APOLLO’s superior observations, routine ranging to all five lunar reflectors on timescales of minutes dramatically improves our ability to gauge lunar orientation and body distortion. This information produces insights into the interior structure and dynamics of the Moon, allowing a more precise determination of the path for the Moon’s center of mass, lending to tests of fundamental gravity. Simultaneously, higher precision range measurements, together with data from a superconducting gravimeter at the

  9. gravity

    Indian Academy of Sciences (India)

    We study the cosmological dynamics for R p exp( λ R ) gravity theory in the metric formalism, using dynamical systems approach. Considering higher-dimensional FRW geometries in case of an imperfect fluid which has two different scale factors in the normal and extra dimensions, we find the exact solutions, and study its ...

  10. Tests of gravity with future space-based experiments

    Science.gov (United States)

    Sakstein, Jeremy

    2018-03-01

    Future space-based tests of relativistic gravitation—laser ranging to Phobos, accelerometers in orbit, and optical networks surrounding Earth—will constrain the theory of gravity with unprecedented precision by testing the inverse-square law, the strong and weak equivalence principles, and the deflection and time delay of light by massive bodies. In this paper, we estimate the bounds that could be obtained on alternative gravity theories that use screening mechanisms to suppress deviations from general relativity in the Solar System: chameleon, symmetron, and Galileon models. We find that space-based tests of the parametrized post-Newtonian parameter γ will constrain chameleon and symmetron theories to new levels, and that tests of the inverse-square law using laser ranging to Phobos will provide the most stringent constraints on Galileon theories to date. We end by discussing the potential for constraining these theories using upcoming tests of the weak equivalence principle, and conclude that further theoretical modeling is required in order to fully utilize the data.

  11. Precision Gravity Tests with Atom Interferometry in Space

    Energy Technology Data Exchange (ETDEWEB)

    Tino, G.M.; Sorrentino, F. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Aguilera, D. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Battelier, B.; Bertoldi, A. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Bodart, Q. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Bongs, K. [Midlands Ultracold Atom Research Centre School of Physics and Astronomy University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Bouyer, P. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Braxmaier, C. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Cacciapuoti, L. [European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Gaaloul, N. [Institute of Quantum Optics, Leibniz Universitaet Hannover, Welfengarten 1, D 30167 Hannover (Germany); Gürlebeck, N. [University of Bremen, Centre of Applied Space Technology and Microgravity (ZARM), Am Fallturm, D - 29359 Bremen (Germany); Hauth, M. [Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); and others

    2013-10-15

    Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual {sup 85}Rb-{sup 87}Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments.

  12. Testing strong gravity with gravitational waves and Love numbers

    International Nuclear Information System (INIS)

    Franzin, E; Cardoso, V; Raposo, G; Pani, P

    2017-01-01

    The LIGO observation of GW150914 has inaugurated the gravitational-wave astronomy era and the possibility of testing gravity in extreme regimes. While distorted black holes are the most convincing sources of gravitational waves, similar signals might be produced also by other compact objects. In particular, we discuss what the gravitational-wave ringdown could tell us about the nature of the emitting object, and how measurements of the tidal Love numbers could help us in understanding the internal structure of compact dark objects. (paper)

  13. Testing the gravity p-median model empirically

    Directory of Open Access Journals (Sweden)

    Kenneth Carling

    2015-12-01

    Full Text Available Regarding the location of a facility, the presumption in the widely used p-median model is that the customer opts for the shortest route to the nearest facility. However, this assumption is problematic on free markets since the customer is presumed to gravitate to a facility by the distance to and the attractiveness of it. The recently introduced gravity p-median model offers an extension to the p-median model that account for this. The model is therefore potentially interesting, although it has not yet been implemented and tested empirically. In this paper, we have implemented the model in an empirical problem of locating vehicle inspections, locksmiths, and retail stores of vehicle spare-parts for the purpose of investigating its superiority to the p-median model. We found, however, the gravity p-median model to be of limited use for the problem of locating facilities as it either gives solutions similar to the p-median model, or it gives unstable solutions due to a non-concave objective function.

  14. More human, more humane: a new approach for testing airborne pollutants.

    Science.gov (United States)

    Potera, Carol

    2007-03-01

    People not only inhale airborne contaminants but also absorb them through the skin. Both routes can set off localized toxic reactions or damage internal organs such as the liver, kidney, and brain. Conventional tests of the toxicity of gases and vapors, in which laboratory animals are exposed to lethal or sub-lethal doses of chemicals, have been criticized as expensive, unethical, inhumane, and time-consuming. Now researchers at the University of New South Wales (UNSW) in Sydney, Australia, have developed an animal-free alternative that uses human cells to test the effects of exposure to airborne toxicants.

  15. Towards strong field tests of beyond Horndeski gravity theories

    Science.gov (United States)

    Sakstein, Jeremy; Babichev, Eugeny; Koyama, Kazuya; Langlois, David; Saito, Ryo

    2017-03-01

    Theories of gravity in the beyond Horndeski class encompass a wide range of scalar-tensor theories that will be tested on cosmological scales over the coming decade. In this work, we investigate the possibility of testing them in the strong field regime by looking at the properties of compact objects—neutron, hyperon, and quark stars—embedded in an asymptotically de Sitter space-time, for a specific subclass of theories. We extend previous works to include slow rotation and find a relation between the dimensionless moment of inertia (I ¯ =I c2/GNM3 ) and the compactness C =GNM /R c2 (an I ¯-C relation), independent of the equation of state, that is reminiscent of but distinct from the general relativity prediction. Several of our equations of state contain hyperons and free quarks, allowing us to revisit the hyperon puzzle. We find that the maximum mass of hyperon stars can be larger than 2 M⊙ for small values of the beyond Horndeski parameter, thus providing a resolution of the hyperon puzzle based on modified gravity. Moreover, stable quark stars exist when hyperonic stars are unstable, which means that the phase transition from hyperon to quark stars is predicted just as in general relativity (GR), albeit with larger quark star masses. Two important and potentially observable consequences of some of the theories we consider are the existence of neutron stars in a range of masses significantly higher than in GR and I ¯-C relations that differ from their GR counterparts. In the former case, we find objects that, if observed, could not be accounted for in GR because they violate the usual GR causality condition. We end by discussing several difficult technical issues that remain to be addressed in order to reach more realistic predictions that may be tested using gravitational wave searches or neutron star observations.

  16. Quantum light in coupled interferometers for quantum gravity tests.

    Science.gov (United States)

    Ruo Berchera, I; Degiovanni, I P; Olivares, S; Genovese, M

    2013-05-24

    In recent years quantum correlations have received a lot of attention as a key ingredient in advanced quantum metrology protocols. In this Letter we show that they provide even larger advantages when considering multiple-interferometer setups. In particular, we demonstrate that the use of quantum correlated light beams in coupled interferometers leads to substantial advantages with respect to classical light, up to a noise-free scenario for the ideal lossless case. On the one hand, our results prompt the possibility of testing quantum gravity in experimental configurations affordable in current quantum optics laboratories and strongly improve the precision in "larger size experiments" such as the Fermilab holometer; on the other hand, they pave the way for future applications to high precision measurements and quantum metrology.

  17. Airborne geoid determination

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Bastos, L.

    2000-01-01

    Airborne geoid mapping techniques may provide the opportunity to improve the geoid over vast areas of the Earth, such as polar areas, tropical jungles and mountainous areas, and provide an accurate "seam-less" geoid model across most coastal regions. Determination of the geoid by airborne methods...... relies on the development of airborne gravimetry, which in turn is dependent on developments in kinematic GPS. Routine accuracy of airborne gravimetry are now at the 2 mGal level, which may translate into 5-10 cm geoid accuracy on regional scales. The error behaviour of airborne gravimetry is well......-suited for geoid determination, with high-frequency survey and downward continuation noise being offset by the low-pass gravity to geoid filtering operation. In the paper the basic principles of airborne geoid determination are outlined, and examples of results of recent airborne gravity and geoid surveys...

  18. SGA-WZ: A New Strapdown Airborne Gravimeter

    DEFF Research Database (Denmark)

    Huang, Yangming; Olesen, Arne Vestergaard; Wu, Meiping

    2012-01-01

    Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance......, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter...... and discussion of the airborne field test results are also given....

  19. Completed Gravity Probe B Undergoes Thermal Vacuum Testing

    Science.gov (United States)

    2000-01-01

    The Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. In this photograph, the completed space vehicle is undergoing thermal vacuum environment testing. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation.)

  20. Time delays across saddles as a test of modified gravity

    International Nuclear Information System (INIS)

    Magueijo, João; Mozaffari, Ali

    2013-01-01

    Modified gravity theories can produce strong signals in the vicinity of the saddles of the total gravitational potential. In a sub-class of these models, this translates into diverging time delays for echoes crossing the saddles. Such models arise from the possibility that gravity might be infrared divergent or confined, and if suitably designed they are very difficult to rule out. We show that Lunar Laser Ranging during an eclipse could probe the time-delay effect within metres of the saddle, thereby proving or excluding these models. Very Large Baseline Interferometry, instead, could target delays across the Jupiter–Sun saddle. Such experiments would shed light on the infrared behaviour of gravity and examine the puzzling possibility that there might be well-hidden regions of strong gravity and even singularities inside the solar system. (fast track communication)

  1. 7 CFR 51.3417 - Optional test for specific gravity.

    Science.gov (United States)

    2010-01-01

    ... be corrected for temperature variations using Table I. (2) A hydrometer specifically designed for determining the specific gravity of potatoes. 3 3 The hydrometer is available from the Potato Chip/Snack Food...

  2. Airborne Wear Particles Emissions fromCommercial Disc Brake Materials– Passenger Car Field Test

    OpenAIRE

    Wahlström, Jens; Olofsson, Ulf; Jansson, Anders; Olander, Lars

    2008-01-01

    Most modern passenger cars have disc brakes on the front wheels, which unlike drum brakes are not sealed off to the ambient air. During braking, there is wear to both the rotor and the pads. This wear process generates particles, which may become airborne. In field tests it is difficult to distinguish these particles from others in the surrounding environment. It may be preferable to use laboratory test stands where the cleanness of the surrounding air can be controlled. The validity of these...

  3. Principal facts for about 16,000 gravity stations in the Nevada Test Site and vicinity

    International Nuclear Information System (INIS)

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

    1989-01-01

    The Nevada Test Site (NTS) and vicinity includes portions of the Goldfield, Caliente, Death Valley, and Las Vegas. This report documents and consolidates previously published and recently compiled gravity data to establish a gravity data base of about 16,000 stations for the NTS and vicinity. While compiling data sets, redundant stations and stations having doubtful locations or gravity values were excluded. Details of compiling the gravity data sets are discussed in later sections. Where feasible, an accuracy code has been assigned to each station so that the accuracy or reliability of each station can be evaluated. This data base was used in preparing complete Bouguer and isostatic gravity maps of the NTS and vicinity. Since publication of the complete Bouguer gravity map, additional data were incorporated into the isostatic gravity map. Gravity data were compiled from five sources: 14,183 stations from the US Geological Survey (USGS), 326 stations from Exploration Data Consultants (EDCON) of Denver, Colorado, 906 stations from the Los Alamos National Laboratory (LANL), 212 stations from the University of Texas at Dallas (UTD), and 48 stations from the Defense Mapping Agency (DMA). This investigation is an effort to study several areas for potential storage of high-level radioactive waste. Gravity stations established under YMP are shown. The objective of this gravity survey was to explore for the presence of plutons. 33 refs., 24 figs., 9 tabs

  4. Principal facts for about 16,000 gravity stations in the Nevada Test Site and vicinity

    International Nuclear Information System (INIS)

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

    1989-01-01

    The Nevada Test Site (NTS) and vicinity includes portions of the Goldfield, Caliente, Death Valley, and Las Vegas. This report documents and consolidates previously published and recently compiled gravity data to establish a gravity data base of about 16,000 stations for the NTS and vicinity. While compiling data sets, redundant stations and stations having doubtful locations or gravity values were excluded. Details of compiling the gravity data sets are discussed in later sections. Where feasible, an accuracy code has been assigned to each station so that the accuracy or reliability of each station can be evaluated. This data base was used in preparing complete Bouguer and isostatic gravity maps of the NTS and vicinity. Since publication of the complete Bouguer gravity map, additional data were incorporated into the isostatic gravity map. Gravity data were compiled from five sources: 14,183 stations from the US Geological Survey (USGS), 326 stations from Exploration Data Consultants (EDCON) of Denver, Colorado, 906 stations from the Los Alamos National Laboratory (LANL), 212 stations from the University of Texas at Dallas (UTD), and 48 stations from the Defense Mapping Agency (DMA). This investigation is an effort to study several areas for potential storage of high-level radioactive waste. Gravity stations established under YMP are shown. The objective of this gravity survey was to explore for the presence of plutons. This volume contains only compiled data

  5. Principal facts of gravity stations with gravity and magnetic profiles from the southwest Nevada Test Site, Nye County, Nevada, as of January 1982

    International Nuclear Information System (INIS)

    Jansma, P.E.; Snyder, D.B.; Ponce, D.A.

    1983-01-01

    Three gravity profiles and principal facts of 2604 gravity stations in the southwest quadrant of the Nevada Test Site are documented in this data report. The residual gravity profiles show the gravity measurements and the smoothed curves derived from these points that were used in geophysical interpretations. The principal facts include station label, latitude, longitude, elevation, observed gravity value, and terrain correction for each station as well as the derived complete Bouguer and isostatic anomalies, reduced at 2.67 g/cm 3 . Accuracy codes, where available, further document the data

  6. Atom-Interferometry Tests of the Isotropy of Post-Newtonian Gravity

    International Nuclear Information System (INIS)

    Mueller, Holger; Chiow, Sheng-wey; Herrmann, Sven; Chu, Steven; Chung, Keng-Yeow

    2008-01-01

    We present a test of the local Lorentz invariance of post-Newtonian gravity by monitoring Earth's gravity with a Mach-Zehnder atom interferometer that features a resolution of up to 8x10 -9 g/√(Hz), the highest reported thus far. Expressed within the standard model extension (SME) or Nordtvedt's anisotropic universe model, the analysis limits four coefficients describing anisotropic gravity at the ppb level and three others, for the first time, at the 10 ppm level. Using the SME we explicitly demonstrate how the experiment actually compares the isotropy of gravity and electromagnetism

  7. Proposal for testing quantum gravity in the lab

    International Nuclear Information System (INIS)

    Ali, Ahmed Farag; Das, Saurya; Vagenas, Elias C.

    2011-01-01

    Attempts to formulate a quantum theory of gravitation are collectively known as quantum gravity. Various approaches to quantum gravity such as string theory and loop quantum gravity, as well as black hole physics and doubly special relativity theories predict a minimum measurable length, or a maximum observable momentum, and related modifications of the Heisenberg Uncertainty Principle to a so-called generalized uncertainty principle (GUP). We have proposed a GUP consistent with string theory, black hole physics, and doubly special relativity theories and have showed that this modifies all quantum mechanical Hamiltonians. When applied to an elementary particle, it suggests that the space that confines it must be quantized, and in fact that all measurable lengths are quantized in units of a fundamental length (which can be the Planck length). On the one hand, this may signal the breakdown of the spacetime continuum picture near that scale, and on the other hand, it can predict an upper bound on the quantum gravity parameter in the GUP, from current observations. Furthermore, such fundamental discreteness of space may have observable consequences at length scales much larger than the Planck scale. Because this influences all the quantum Hamiltonians in an universal way, it predicts quantum gravity corrections to various quantum phenomena. Therefore, in the present work we compute these corrections to the Lamb shift, simple harmonic oscillator, Landau levels, and the tunneling current in a scanning tunneling microscope.

  8. Exploring the Recovery Lakes region and interior Dronning Maud Land, East Antarctica, with airborne gravity, magnetic and radar measurements

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Ferraccioli, Fausto

    2017-01-01

    for major Dronning Maud Land ice stream systems, from the grounding lines up to the Recovery Lakes drainage basin, and filled in major data voids in Antarctic data compilations, such as AntGP for gravity data, ADMAP for magnetic data and BEDMAP2 for ice thickness data and the sub-ice topography. We present...

  9. More Human, More Humane: A New Approach for Testing Airborne Pollutants

    OpenAIRE

    Potera, Carol

    2007-01-01

    People not only inhale airborne contaminants but also absorb them through the skin. Both routes can set off localized toxic reactions or damage internal organs such as the liver, kidney, and brain. Conventional tests of the toxicity of gases and vapors, in which laboratory animals are exposed to lethal or sub-lethal doses of chemicals, have been criticized as expensive, unethical, inhumane, and time-consuming. Now researchers at the University of New South Wales (UNSW) in Sydney, Australia, h...

  10. Type I Shell Galaxies as a Test of Gravity Models

    Energy Technology Data Exchange (ETDEWEB)

    Vakili, Hajar; Rahvar, Sohrab [Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran, Islamic Republic of); Kroupa, Pavel, E-mail: vakili@physics.sharif.edu [Helmholtz-Institut für Strahlen-und Kernphysik, Universität Bonn, Nussallee 14-16, D-53115 Bonn (Germany)

    2017-10-10

    Shell galaxies are understood to form through the collision of a dwarf galaxy with an elliptical galaxy. Shell structures and kinematics have been noted to be independent tools to measure the gravitational potential of the shell galaxies. We compare theoretically the formation of shells in Type I shell galaxies in different gravity theories in this work because this is so far missing in the literature. We include Newtonian plus dark halo gravity, and two non-Newtonian gravity models, MOG and MOND, in identical initial systems. We investigate the effect of dynamical friction, which by slowing down the dwarf galaxy in the dark halo models limits the range of shell radii to low values. Under the same initial conditions, shells appear on a shorter timescale and over a smaller range of distances in the presence of dark matter than in the corresponding non-Newtonian gravity models. If galaxies are embedded in a dark matter halo, then the merging time may be too rapid to allow multi-generation shell formation as required by observed systems because of the large dynamical friction effect. Starting from the same initial state, the observation of small bright shells in the dark halo model should be accompanied by large faint ones, while for the case of MOG, the next shell generation patterns iterate with a specific time delay. The first shell generation pattern shows a degeneracy with the age of the shells and in different theories, but the relative distance of the shells and the shell expansion velocity can break this degeneracy.

  11. Astrophysical tests of scale-covariant gravity theories

    International Nuclear Information System (INIS)

    Mansfield, V.N.; Malin, S.

    1980-01-01

    Starting from the most general form of the conservation laws in scale-covariant gravitation theory, a conservation of energy equation appropriate for stars is derived. Applications to white dwarfs and neutron stars reveal serious difficulties for some choices of gauge that have been frequently employed in the literature on scale-covariant gravity. We also show how to restrict some of the possible gauges that result from theories which are independent of the Large Numbers Hypothesis

  12. The role of satellite altimetry in gravity field modelling in coastal areas

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per

    2000-01-01

    global uniform gravity information with very high resolution, and these global marine gravity fields are registered on a two by two minute grid corresponding to 4 by 4 kilometres at the equator. In this presentation several coastal complications in deriving the marine gravity field from satellite...... altimetry will be investigated using the KMS98 gravity field. Comparison with other sources of gravity field information like airborne and marine gravity observations will be carried out and two fundamentally different test areas (Azores and Skagerak) will be studied to investigated the different role...

  13. Modified Gravity and its test on galaxy clusters

    Science.gov (United States)

    Nieuwenhuizen, Theodorus M.; Morandi, Andrea; Limousin, Marceau

    2018-05-01

    The MOdified Gravity (MOG) theory of J. Moffat assumes a massive vector particle which causes a repulsive contribution to the tensor gravitation. For the galaxy cluster A1689 new data for the X-ray gas and the strong lensing properties are presented. Fits to MOG are possible by adjusting the galaxy density profile. However, this appears to work as an effective dark matter component, posing a serious problem for MOG. New gas and strong lensing data for the cluster A1835 support these conclusions and point at a tendency of the gas alone to overestimate the lensing effects in MOG theory.

  14. Test Equal Bending by Gravity for Space and Time

    Science.gov (United States)

    Sweetser, Douglas

    2009-05-01

    For the simplest problem of gravity - a static, non-rotating, spherically symmetric source - the solution for spacetime bending around the Sun should be evenly split between time and space. That is true to first order in M/R, and confirmed by experiment. At second order, general relativity predicts different amounts of contribution from time and space without a physical justification. I show an exponential metric is consistent with light bending to first order, measurably different at second order. All terms to all orders show equal contributions from space and time. Beautiful minimalism is Nature's way.

  15. Topology and dark energy: testing gravity in voids.

    Science.gov (United States)

    Spolyar, Douglas; Sahlén, Martin; Silk, Joe

    2013-12-13

    Modified gravity has garnered interest as a backstop against dark matter and dark energy (DE). As one possible modification, the graviton can become massive, which introduces a new scalar field--here with a Galileon-type symmetry. The field can lead to a nontrivial equation of state of DE which is density and scale dependent. Tension between type Ia supernovae and Planck could be reduced. In voids, the scalar field dramatically alters the equation of state of DE, induces a soon-observable gravitational slip between the two metric potentials, and develops a topological defect (domain wall) due to a nontrivial vacuum structure for the field.

  16. A nanonewton force facility to test Newton's law of gravity at micro- and submicrometer distances

    International Nuclear Information System (INIS)

    Nesterov, Vladimir; Buetefisch, Sebastian; Koenders, Ludger

    2013-01-01

    An experiment to test Newton's law of gravity at micro- and submicrometer distances using a nanonewton force facility at PTB and modern microtechnologies is proposed. It is anticipated that the proposed method can advance the search for non-Newtonian gravity forces via an enhanced sensitivity of 10 3 to 10 4 in comparison to current experiments at the micrometer length scale. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Testing universal relations of neutron stars with a nonlinear matter-gravity coupling theory

    International Nuclear Information System (INIS)

    Sham, Y.-H.; Lin, L.-M.; Leung, P. T.

    2014-01-01

    Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.

  18. Testing Universal Relations of Neutron Stars with a Nonlinear Matter-Gravity Coupling Theory

    Science.gov (United States)

    Sham, Y.-H.; Lin, L.-M.; Leung, P. T.

    2014-02-01

    Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.

  19. Ground-based self-gravity tests for LISA Pathfinder and LISA

    International Nuclear Information System (INIS)

    Trenkel, C; Warren, C; Wealthy, D

    2009-01-01

    Gravitational coupling between the free-falling test masses and the surrounding spacecraft is one of the dominant noise sources for both LISA Pathfinder and LISA. At present, there are no plans to verify any of the self-gravity requirements by test, on the ground. Here, we explore the possibilities of conducting such tests, using a customised torsion balance. We discuss the main sources of systematic and statistical uncertainty present in such a set-up. Our preliminary assessment indicates that the sensitivity is sufficient to carry out meaningful self-gravity tests.

  20. New error calibration tests for gravity models using subset solutions and independent data - Applied to GEM-T3

    Science.gov (United States)

    Lerch, F. J.; Nerem, R. S.; Chinn, D. S.; Chan, J. C.; Patel, G. B.; Klosko, S. M.

    1993-01-01

    A new method has been developed to provide a direct test of the error calibrations of gravity models based on actual satellite observations. The basic approach projects the error estimates of the gravity model parameters onto satellite observations, and the results of these projections are then compared with data residual computed from the orbital fits. To allow specific testing of the gravity error calibrations, subset solutions are computed based on the data set and data weighting of the gravity model. The approach is demonstrated using GEM-T3 to show that the gravity error estimates are well calibrated and that reliable predictions of orbit accuracies can be achieved for independent orbits.

  1. LINKING TESTS OF GRAVITY ON ALL SCALES: FROM THE STRONG-FIELD REGIME TO COSMOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Tessa [Astrophysics, Denys Wilkinson Building, Keble Road, University of Oxford, Oxford, OX1 3RH (United Kingdom); Psaltis, Dimitrios [Astronomy Department, University of Arizona, 933 North Cherry Avenue., Tucson, AZ 85721 (United States); Skordis, Constantinos, E-mail: tessa.baker@astro.ox.ac.uk, E-mail: dpsaltis@email.arizona.edu, E-mail: skordis@ucy.ac.cy [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2015-03-20

    The current effort to test general relativity (GR) employs multiple disparate formalisms for different observables, obscuring the relations between laboratory, astrophysical, and cosmological constraints. To remedy this situation, we develop a parameter space for comparing tests of gravity on all scales in the universe. In particular, we present new methods for linking cosmological large-scale structure, the cosmic microwave background, and gravitational waves with classic PPN tests of gravity. Diagrams of this gravitational parameter space reveal a noticeable untested regime. The untested window, which separates small-scale systems from the troubled cosmological regime, could potentially hide the onset of corrections to GR.

  2. Could quantum gravity phenomenology be tested with high intensity lasers?

    International Nuclear Information System (INIS)

    Magueijo, Joao

    2006-01-01

    In phenomenological quantum gravity theories, Planckian behavior is triggered by the energy of elementary particles approaching the Planck energy, E P , but it is also possible that anomalous behavior strikes systems of particles with total energy near E P . This is usually perceived to be pathological and has been labeled 'the soccer ball problem'. We point out that there is no obvious contradiction with experiment if coherent collections of particles with bulk energy of order E P do indeed display Planckian behavior, a possibility that would open a new experimental window. Unfortunately, field theory realizations of 'doubly' (or deformed) special relativity never exhibit a soccer ball problem; we present several formulations where this is undeniably true. Upon closer scrutiny we discover that the only chance for Planckian behavior to be triggered by large coherent energies involves the details of second quantization. We find a formulation where the quanta have their energy-momentum (mass-shell) relations deformed as a function of the bulk energy of the coherent packet to which they belong, rather than the frequency. Given ongoing developments in laser technology, such a possibility would be of great experimental interest

  3. Tests of local Lorentz invariance violation of gravity in the standard model extension with pulsars.

    Science.gov (United States)

    Shao, Lijing

    2014-03-21

    The standard model extension is an effective field theory introducing all possible Lorentz-violating (LV) operators to the standard model and general relativity (GR). In the pure-gravity sector of minimal standard model extension, nine coefficients describe dominant observable deviations from GR. We systematically implemented 27 tests from 13 pulsar systems to tightly constrain eight linear combinations of these coefficients with extensive Monte Carlo simulations. It constitutes the first detailed and systematic test of the pure-gravity sector of minimal standard model extension with the state-of-the-art pulsar observations. No deviation from GR was detected. The limits of LV coefficients are expressed in the canonical Sun-centered celestial-equatorial frame for the convenience of further studies. They are all improved by significant factors of tens to hundreds with existing ones. As a consequence, Einstein's equivalence principle is verified substantially further by pulsar experiments in terms of local Lorentz invariance in gravity.

  4. A test of Newton's Law of Gravity using the BREN Tower, Nevada

    International Nuclear Information System (INIS)

    Kasameyer, P.; Thomas, J.; Fackler, O.; Mugge, M.; Kammeraad, J.; Millett, M.; Harris, B.; Felske, D.

    1989-01-01

    We predicted gravity values on a tower by upward continuing an extensive set of surface data in order to test the 1/r 2 dependence of Newton's Law of Universal Gravitation. We measured gravity at 12 heights up to 454 m on a tower at the Nevada Test Site, and at 91 locations on the surface of the earth within 2.5 kilometers of the tower. These data have been combined with 60,000 surface gravity measurements within 300 kilometers of the tower and have been used to predict the gravitational field on the tower via a solution of Laplace's equation. A discrepancy between the observed gravity values and the prediction could suggest a breakdown of Newtonian Gravity, but we observe none. Our preliminary results are consistent with the Newtonian hypothesis to within 93 +- 95 μgals at the top of the tower, a result which conflicts with the previously reported 500 μgal non-Newtonian signal seen at 562 meters above the earth. 24 refs., 2 figs

  5. TESTING OF LAND COVER CLASSIFICATION FROM MULTISPECTRAL AIRBORNE LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    K. Bakuła

    2016-06-01

    Full Text Available Multispectral Airborne Laser Scanning provides a new opportunity for airborne data collection. It provides high-density topographic surveying and is also a useful tool for land cover mapping. Use of a minimum of three intensity images from a multiwavelength laser scanner and 3D information included in the digital surface model has the potential for land cover/use classification and a discussion about the application of this type of data in land cover/use mapping has recently begun. In the test study, three laser reflectance intensity images (orthogonalized point cloud acquired in green, near-infrared and short-wave infrared bands, together with a digital surface model, were used in land cover/use classification where six classes were distinguished: water, sand and gravel, concrete and asphalt, low vegetation, trees and buildings. In the tested methods, different approaches for classification were applied: spectral (based only on laser reflectance intensity images, spectral with elevation data as additional input data, and spectro-textural, using morphological granulometry as a method of texture analysis of both types of data: spectral images and the digital surface model. The method of generating the intensity raster was also tested in the experiment. Reference data were created based on visual interpretation of ALS data and traditional optical aerial and satellite images. The results have shown that multispectral ALS data are unlike typical multispectral optical images, and they have a major potential for land cover/use classification. An overall accuracy of classification over 90% was achieved. The fusion of multi-wavelength laser intensity images and elevation data, with the additional use of textural information derived from granulometric analysis of images, helped to improve the accuracy of classification significantly. The method of interpolation for the intensity raster was not very helpful, and using intensity rasters with both first and

  6. A general framework to test gravity using galaxy clusters - I. Modelling the dynamical mass of haloes in f(R) gravity

    Science.gov (United States)

    Mitchell, Myles A.; He, Jian-hua; Arnold, Christian; Li, Baojiu

    2018-06-01

    We propose a new framework for testing gravity using cluster observations, which aims to provide an unbiased constraint on modified gravity models from Sunyaev-Zel'dovich (SZ) and X-ray cluster counts and the cluster gas fraction, among other possible observables. Focusing on a popular f(R) model of gravity, we propose a novel procedure to recalibrate mass scaling relations from Λ cold dark matter (ΛCDM) to f(R) gravity for SZ and X-ray cluster observables. We find that the complicated modified gravity effects can be simply modelled as a dependence on a combination of the background scalar field and redshift, fR(z)/(1 + z), regardless of the f(R) model parameter. By employing a large suite of N-body simulations, we demonstrate that a theoretically derived tanh fitting formula is in excellent agreement with the dynamical mass enhancement of dark matter haloes for a large range of background field parameters and redshifts. Our framework is sufficiently flexible to allow for tests of other models and inclusion of further observables, and the one-parameter description of the dynamical mass enhancement can have important implications on the theoretical modelling of observables and on practical tests of gravity.

  7. Coupling of linearized gravity to nonrelativistic test particles: Dynamics in the general laboratory frame

    International Nuclear Information System (INIS)

    Speliotopoulos, A.D.; Chiao, Raymond Y.

    2004-01-01

    The coupling of gravity to matter is explored in the linearized gravity limit. The usual derivation of gravity-matter couplings within the quantum-field-theoretic framework is reviewed. A number of inconsistencies between this derivation of the couplings and the known results of tidal effects on test particles according to classical general relativity are pointed out. As a step towards resolving these inconsistencies, a general laboratory frame fixed on the worldline of an observer is constructed. In this frame, the dynamics of nonrelativistic test particles in the linearized gravity limit is studied, and their Hamiltonian dynamics is derived. It is shown that for stationary metrics this Hamiltonian reduces to the usual Hamiltonian for nonrelativistic particles undergoing geodesic motion. For nonstationary metrics with long-wavelength gravitational waves present (GWs), it reduces to the Hamiltonian for a nonrelativistic particle undergoing geodesic deviation motion. Arbitrary-wavelength GWs couple to the test particle through a vector-potential-like field N a , the net result of the tidal forces that the GW induces in the system, namely, a local velocity field on the system induced by tidal effects, as seen by an observer in the general laboratory frame. Effective electric and magnetic fields, which are related to the electric and magnetic parts of the Weyl tensor, are constructed from N a that obey equations of the same form as Maxwell's equations. A gedankin gravitational Aharonov-Bohm-type experiment using N a to measure the interference of quantum test particles is presented

  8. Breaking diffeomorphism invariance and tests for the emergence of gravity

    International Nuclear Information System (INIS)

    Anber, Mohamed M.; Aydemir, Ufuk; Donoghue, John F.

    2010-01-01

    If general relativity is an emergent phenomenon, there may be small violations of diffeomorphism invariance. We propose a phenomenology of perturbatively small violations of general relativity by the inclusion of terms which break general covariance. These can be tested by matching to the parameterized post-Newtonian formalism. The most sensitive tests involve pulsar timing and provide an extremely strong bound, with a dimensionless constraint of order 10 -20 relative to gravitational strength.

  9. Testing the master constraint programme for loop quantum gravity: V. Interacting field theories

    International Nuclear Information System (INIS)

    Dittrich, B; Thiemann, T

    2006-01-01

    This is the fifth and final paper in our series of five in which we test the master constraint programme for solving the Hamiltonian constraint in loop quantum gravity. Here we consider interacting quantum field theories, specifically we consider the non-Abelian Gauss constraints of Einstein-Yang-Mills theory and 2 + 1 gravity. Interestingly, while Yang-Mills theory in 4D is not yet rigorously defined as an ordinary (Wightman) quantum field theory on Minkowski space, in background-independent quantum field theories such as loop quantum gravity (LQG) this might become possible by working in a new, background-independent representation. While for the Gauss constraint the master constraint can be solved explicitly, for the 2 + 1 theory we are only able to rigorously define the master constraint operator. We show that the, by other methods known, physical Hilbert is contained in the kernel of the master constraint, however, to systematically derive it by only using spectral methods is as complicated as for 3 + 1 gravity and we therefore leave the complete analysis for 3 + 1 gravity

  10. The New Era of Precision Cosmology: Testing Gravity at Large Scales

    Science.gov (United States)

    Prescod-Weinstein, Chanda

    2011-01-01

    Cosmic acceleration may be the biggest phenomenological mystery in cosmology today. Various explanations for its cause have been proposed, including the cosmological constant, dark energy and modified gravities. Structure formation provides a strong test of any cosmic acceleration model because a successful dark energy model must not inhibit the development of observed large-scale structures. Traditional approaches to studies of structure formation in the presence of dark energy ore modified gravity implement the Press & Schechter formalism (PGF). However, does the PGF apply in all cosmologies? The search is on for a better understanding of universality in the PGF In this talk, I explore the potential for universality and talk about what dark matter haloes may be able to tell us about cosmology. I will also discuss the implications of this and new cosmological experiments for better understanding our theory of gravity.

  11. TOPOLOGY OF A LARGE-SCALE STRUCTURE AS A TEST OF MODIFIED GRAVITY

    International Nuclear Information System (INIS)

    Wang Xin; Chen Xuelei; Park, Changbom

    2012-01-01

    The genus of the isodensity contours is a robust measure of the topology of a large-scale structure, and it is relatively insensitive to nonlinear gravitational evolution, galaxy bias, and redshift-space distortion. We show that the growth of density fluctuations is scale dependent even in the linear regime in some modified gravity theories, which opens a new possibility of testing the theories observationally. We propose to use the genus of the isodensity contours, an intrinsic measure of the topology of the large-scale structure, as a statistic to be used in such tests. In Einstein's general theory of relativity, density fluctuations grow at the same rate on all scales in the linear regime, and the genus per comoving volume is almost conserved as structures grow homologously, so we expect that the genus-smoothing-scale relation is basically time independent. However, in some modified gravity models where structures grow with different rates on different scales, the genus-smoothing-scale relation should change over time. This can be used to test the gravity models with large-scale structure observations. We study the cases of the f(R) theory, DGP braneworld theory as well as the parameterized post-Friedmann models. We also forecast how the modified gravity models can be constrained with optical/IR or redshifted 21 cm radio surveys in the near future.

  12. Astrophysical tests of modified gravity: Constraints from distance indicators in the nearby universe

    International Nuclear Information System (INIS)

    Jain, Bhuvnesh; Vikram, Vinu; Sakstein, Jeremy

    2013-01-01

    We use distance measurements in the nearby universe to carry out new tests of gravity, surpassing other astrophysical tests by over two orders of magnitude for chameleon theories. The three nearby distance indicators—cepheids, tip of the red giant branch (TRGB) stars, and water masers—operate in gravitational fields of widely different strengths. This enables tests of scalar-tensor gravity theories because they are screened from enhanced forces to different extents. Inferred distances from cepheids and TRGB stars are altered (in opposite directions) over a range of chameleon gravity theory parameters well below the sensitivity of cosmological probes. Using published data, we have compared cepheid and TRGB distances in a sample of unscreened dwarf galaxies within 10 Mpc. We use a comparable set of screened galaxies as a control sample. We find no evidence for the order unity force enhancements expected in these theories. Using a two-parameter description of the models (the coupling strength and background field value), we obtain constraints on both the chameleon and symmetron screening scenarios. In particular we show that f(R) models with background field values f R0 above 5 × 10 –7 are ruled out at the 95% confidence level. We also compare TRGB and maser distances to the galaxy NGC 4258 as a second test for larger field values. While there are several approximations and caveats in our study, our analysis demonstrates the power of gravity tests in the local universe. We discuss the prospects for additional improved tests with future observations.

  13. Astrophysical tests of modified gravity: Constraints from distance indicators in the nearby universe

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Bhuvnesh; Vikram, Vinu [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Sakstein, Jeremy [Department of Applied Mathematics and Theoretical Physics, Cambridge CB3 0WA (United Kingdom)

    2013-12-10

    We use distance measurements in the nearby universe to carry out new tests of gravity, surpassing other astrophysical tests by over two orders of magnitude for chameleon theories. The three nearby distance indicators—cepheids, tip of the red giant branch (TRGB) stars, and water masers—operate in gravitational fields of widely different strengths. This enables tests of scalar-tensor gravity theories because they are screened from enhanced forces to different extents. Inferred distances from cepheids and TRGB stars are altered (in opposite directions) over a range of chameleon gravity theory parameters well below the sensitivity of cosmological probes. Using published data, we have compared cepheid and TRGB distances in a sample of unscreened dwarf galaxies within 10 Mpc. We use a comparable set of screened galaxies as a control sample. We find no evidence for the order unity force enhancements expected in these theories. Using a two-parameter description of the models (the coupling strength and background field value), we obtain constraints on both the chameleon and symmetron screening scenarios. In particular we show that f(R) models with background field values f {sub R0} above 5 × 10{sup –7} are ruled out at the 95% confidence level. We also compare TRGB and maser distances to the galaxy NGC 4258 as a second test for larger field values. While there are several approximations and caveats in our study, our analysis demonstrates the power of gravity tests in the local universe. We discuss the prospects for additional improved tests with future observations.

  14. An Airborne Parachute Compartment Test Bed for the Orion Parachute Test Program

    Science.gov (United States)

    Moore, James W.; Romero, Leah M.

    2013-01-01

    The test program developing parachutes for the Orion/MPCV includes drop tests with parachutes deployed from an Orion-like parachute compartment at a wide range of dynamic pressures. Aircraft and altitude constraints precluded the use of an Orion boilerplate capsule for several test points. Therefore, a dart-shaped test vehicle with a hi-fidelity mock-up of the Orion parachute compartment has been developed. The available aircraft options imposed constraints on the test vehicle development and concept of operations. Delivery of this test vehicle to the desired velocity, altitude, and orientation required for the test is a di cult problem involving multiple engineering disciplines. This paper describes the development of the test technique. The engineering challenges include extraction from an aircraft, reposition of the extraction parachute, and mid-air separation of two vehicles, neither of which has an active attitude control system. The desired separation behavior is achieved by precisely controlling the release point using on-board monitoring of the motion. The design of the test vehicle is also described. The trajectory simulations and other analyses used to develop this technique and predict the behavior of the test vehicle are reviewed in detail. The application of the technique on several successful drop tests is summarized.

  15. Tonopah Test Range Air Monitoring: CY2015 Meteorological, Radiological, and Airborne Particulate Observations

    International Nuclear Information System (INIS)

    Nikolich, George; Shadel, Craig; Chapman, Jenny; McCurdy, Greg; Etyemezian, Vicken; Miller, Julianne J.; Mizell, Steve

    2016-01-01

    In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). The operation resulted in radionuclide-contaminated soils at the Clean Slate I, II, and III sites. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III, and at the TTR Sandia National Laboratories (SNL) Range Operations Control (ROC) center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soil beyond the physical and administrative boundaries of the sites. Radionuclide assessment of airborne particulates in 2015 found the gross alpha and gross beta values of dust collected from the filters at the monitoring stations are consistent with background conditions. The meteorological and particle monitoring indicate that conditions for wind-borne contaminant movement exist at the Clean Slate sites and that, although the transport of radionuclide-contaminated soil by suspension has not been detected, movement by saltation is occurring.

  16. Tonopah Test Range Air Monitoring: CY2015 Meteorological, Radiological, and Airborne Particulate Observations

    Energy Technology Data Exchange (ETDEWEB)

    Nikolich, George [Nevada University, Reno, NV (United States). Desert Research Inst.; Shadel, Craig [Nevada University, Reno, NV (United States). Desert Research Inst.; Chapman, Jenny [Nevada University, Reno, NV (United States). Desert Research Inst.; McCurdy, Greg [Nevada University, Reno, NV (United States). Desert Research Inst.; Etyemezian, Vicken [Nevada University, Reno, NV (United States). Desert Research Inst.; Miller, Julianne J. [Nevada University, Reno, NV (United States). Desert Research Inst.; Mizell, Steve [Nevada University, Reno, NV (United States). Desert Research Inst.

    2016-09-01

    In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). The operation resulted in radionuclide-contaminated soils at the Clean Slate I, II, and III sites. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III, and at the TTR Sandia National Laboratories (SNL) Range Operations Control (ROC) center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soil beyond the physical and administrative boundaries of the sites. Radionuclide assessment of airborne particulates in 2015 found the gross alpha and gross beta values of dust collected from the filters at the monitoring stations are consistent with background conditions. The meteorological and particle monitoring indicate that conditions for wind-borne contaminant movement exist at the Clean Slate sites and that, although the transport of radionuclide-contaminated soil by suspension has not been detected, movement by saltation is occurring.

  17. Testing modified gravity with globular clusters: the case of NGC 2419

    Science.gov (United States)

    Llinares, Claudio

    2018-05-01

    The dynamics of globular clusters has been studied in great detail in the context of general relativity as well as with modifications of gravity that strongly depart from the standard paradigm such as Modified Newtonian Dynamics. However, at present there are no studies that aim to test the impact that less extreme modifications of gravity (e.g. models constructed as alternatives to dark energy) have on the behaviour of globular clusters. This Letter presents fits to the velocity dispersion profile of the cluster NGC 2419 under the symmetron-modified gravity model. The data show an increase in the velocity dispersion towards the centre of the cluster which could be difficult to explain within general relativity. By finding the best-fitting solution associated with the symmetron model, we show that this tension does not exist in modified gravity. However, the best-fitting parameters give a model that is inconsistent with the dynamics of the Solar system. Exploration of different screening mechanisms should give us the chance to understand if it is possible to maintain the appealing properties of the symmetron model when it comes to globular clusters and at the same time recover the Solar system dynamics properly.

  18. Extreme gravity tests with gravitational waves from compact binary coalescences: (II) ringdown

    Science.gov (United States)

    Berti, Emanuele; Yagi, Kent; Yang, Huan; Yunes, Nicolás

    2018-05-01

    The LIGO/Virgo detections of binary black hole mergers marked a watershed moment in astronomy, ushering in the era of precision tests of Kerr dynamics. We review theoretical and experimental challenges that must be overcome to carry out black hole spectroscopy with present and future gravitational wave detectors. Among other topics, we discuss quasinormal mode excitation in binary mergers, astrophysical event rates, tests of black hole dynamics in modified theories of gravity, parameterized "post-Kerr" ringdown tests, exotic compact objects, and proposed data analysis methods to improve spectroscopic tests of Kerr dynamics by stacking multiple events.

  19. Astrophysical tests of gravity: a screening map of the nearby universe

    Energy Technology Data Exchange (ETDEWEB)

    Cabré, Anna; Vikram, Vinu; Jain, Bhuvnesh [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104-6396 (United States); Zhao, Gong-Bo; Koyama, Kazuya, E-mail: annanusca@gmail.com, E-mail: vinu@sas.upenn.edu, E-mail: gong-bo.zhao@port.ac.uk, E-mail: bjain@physics.upenn.edu, E-mail: Kazuya.Koyama@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)

    2012-07-01

    Astrophysical tests of modified gravity theories in the nearby universe have been emphasized recently by Hui 2009 and Jain 2011. A key element of such tests is the screening mechanism whereby general relativity is restored in massive halos or high density environments like the Milky Way. In chameleon theories of gravity, including all f(R) models, field dwarf galaxies may be unscreened and therefore feel an extra force, as opposed to screened galaxies. The first step to study differences between screened and unscreened galaxies is to create a 3D screening map. We use N-body simulations to test and calibrate simple approximations to determine the level of screening in galaxy catalogs. Sources of systematic errors in the screening map due to observational inaccuracies are modeled and their contamination is estimated. We then apply our methods to create a map out to 200 Mpc in the Sloan Digital Sky Survey footprint using data from the Sloan survey and other sources. In two companion papers this map will be used to carry out new tests of gravity using distance indicators and the disks of dwarf galaxies. We also make our screening map publicly available.

  20. Advances in the testing and evaluation of airborne radar through realtime simulation of synthetic clutter

    CSIR Research Space (South Africa)

    Strydom, JJ

    2011-11-01

    Full Text Available and Evaluation of Airborne Radar through Realtime Simulation of Synthetic Clutter Presenter: Jurgen Strydom Systems Engineer & Signal Analyst Experimental EW Systems, CSIR Email: jjstrydom@csir.co.za Co-authors: Jacques Cilliers, CSIR 48th AOC Conference... environment simulation domain ? CSIR 2011 Slide 2 ? Technological advancements and challenges in the simulation of clutter for an airborne radar platform is discussed Where we are from: South Africa ? CSIR 2011 Slide 3 Health Natural Environment...

  1. Astrophysical tests for the Novello-De Lorenci-Luciane theory of gravity

    International Nuclear Information System (INIS)

    Mosquera Cuesta, H.J.

    2001-01-01

    The Novello-DeLorenci-Luciane (NDL) field theory of gravitation predicts that gravitational waves (GWs) follow geodesics of a modified (effective) geometry with a speed lower than the velocity of light. The theory also demonstrates that GWs exhibit the phenomenon of birefringence, formerly believed to be exclusive of electromagnetic waves. Here prospective astrophysical tests of these predictions are proposed. I point out that future measurements of gravitational waves in coincidence with a non-gravitational process such as a neutrino burst (and likely a burst of gamma-rays) may prove useful to discriminate among all the existing theories of gravity. It is also stressed that microlensing of gravitational waves emitted by known galactic sources (i.e., pulsars) in the bulge, lensed by either the Galaxy's central black hole (Sgr A*) or a MACHO object adrift among the Milky Way's stars, may provide a clean test of the birefringence phenomenon implied by the NDL gravity theory. (author)

  2. Analysis of Properties of Reflectance Reference Targets for Permanent Radiometric Test Sites of High Resolution Airborne Imaging Systems

    Directory of Open Access Journals (Sweden)

    Eero Ahokas

    2010-08-01

    Full Text Available Reliable and optimal exploitation of rapidly developing airborne imaging methods requires geometric and radiometric quality assurance of production systems in operational conditions. Permanent test sites are the most promising approach for cost-efficient performance assessment. Optimal construction of permanent radiometric test sites for high resolution airborne imaging systems is an unresolved issue. The objective of this study was to assess the performance of commercially available gravels and painted and unpainted concrete targets for permanent, open-air radiometric test sites under sub-optimal climate conditions in Southern Finland. The reflectance spectrum and reflectance anisotropy and their stability were characterized during the summer of 2009. The management of reflectance anisotropy and stability were shown to be the key issues for better than 5% reflectance accuracy.

  3. Airborne radionuclides of concern and their measurement in monitoring a Comprehensive Test Ban Treaty

    International Nuclear Information System (INIS)

    Perkins, R.W.; Miley, H.S.; Hensley, W.K.; Abel, K.H.

    1995-01-01

    The U.S. Department of Energy (DOE) is conducting radioanalytical developmental programs with the goal of providing near-real-time analysis technology for airborne signature radionuclides which are indicative of a nuclear weapons test in any of the earth's environments. If a test were conducted in the atmosphere or above the atmosphere, then the full spectrum of fission and activation products, together with residues from the device would be dispersed in the atmosphere. However, if a nuclear test were conducted underground or under water, the emission could range from a major to a very minor vent, and the material released would likely consist mainly of noble gas radionuclides and the radioiodines. Since many of the noble gases decay to form particulate radionuclides, these may serve as the more sensitive signatures. For example, Ba-140 is a daughter of Xe-140 (13.6 s), and Cs-137 is a daughter of Xe-137 (3.82 min). Both of these have been observed in large amounts relative to other fission products in dynamic venting of U.S. underground nuclear detonations. Large amounts of radionuclides are produced from even a comparatively small nuclear detonation. For example, a 10-KT fission device will produce approximately a megacurie of Ba-140 and of several other radionuclides with half-lives of days to weeks. If such a device were detonated in the atmosphere at midlatitude, it would easily be observable at downwind monitoring sites during its first and subsequent circumnavigations of the earth. Efficient and practical methods for the near-real-time analysis of both particulate and gaseous radionuclides are important to an effective monitoring and attribution program in support of a Comprehensive Test Ban Treaty (CTBT); methods for this purpose are being pursued

  4. Live Coral Cover Index Testing and Application with Hyperspectral Airborne Image Data

    Directory of Open Access Journals (Sweden)

    Karen E. Joyce

    2013-11-01

    Full Text Available Coral reefs are complex, heterogeneous environments where it is common for the features of interest to be smaller than the spatial dimensions of imaging sensors. While the coverage of live coral at any point in time is a critical environmental management issue, image pixels may represent mixed proportions of coverage. In order to address this, we describe the development, application, and testing of a spectral index for mapping live coral cover using CASI-2 airborne hyperspectral high spatial resolution imagery of Heron Reef, Australia. Field surveys were conducted in areas of varying depth to quantify live coral cover. Image statistics were extracted from co-registered imagery in the form of reflectance, derivatives, and band ratios. Each of the spectral transforms was assessed for their correlation with live coral cover, determining that the second derivative around 564 nm was the most sensitive to live coral cover variations(r2 = 0.63. Extensive field survey was used to transform relative to absolute coral cover, which was then applied to produce a live coral cover map of Heron Reef. We present the live coral cover index as a simple and viable means to estimate the amount of live coral over potentially thousands of km2 and in clear-water reefs.

  5. Preliminary results of absolute and high-precision gravity measurements at the Nevada Test Site and vicinity, Nevada

    International Nuclear Information System (INIS)

    Zumberge, M.A.; Harris, R.N.; Oliver, H.W.; Sasagawa, G.S.; Ponce, D.A.

    1988-01-01

    Absolute gravity measurements were made at 4 sites in southern Nevada using the absolute gravity free-fall apparatus. Three of the sites are located on the Nevada Test Site at Mercury, Yucca Pass, and in northern Jackass Flats. The fourth site is at Kyle Canyon ranger station near Charleston Park where observed gravity is 216.19 mGal lower than at Mercury. Although there is an uncertainty of about 0.02 mGal in the absolute measured values, their gravity differences are considered accurate to about 0.03 mGal. Therefore, the absolute measurements should provide local control for the calibration of gravity meters between Mercury and Kyle Canyon ranger station to about 1 to 2 parts in 10,000. The average gravity differences between Mercury and Kyle Canyon obtained using LaCoste and Romberg gravity meters is 216.13 mGal, 0.06 mGal lower, or 3 parts in 10,000 lower than using the absolute gravity meter. Because of the discrepancy between the comparison of the absolute and relative gravity meters, more absolute and relative gravity control in southern Nevada, as well as the Mt. Hamilton area where the LaCoste and Romberg instruments were calibrated, is needed. Multiple gravity meter ties were also made between each of the four absolute stations to nearby base stations located on bedrock. These stations were established to help monitor possible real changes in gravity at the absolute sites that could result from seasonal variations in the depth to the water table or other local mass changes. 8 refs., 16 figs., 7 tabs

  6. Testing effective quantum gravity with gravitational waves from extreme mass ratio inspirals

    International Nuclear Information System (INIS)

    Yunes, N; Sopuerta, C F

    2010-01-01

    Testing deviation of GR is one of the main goals of the proposed Laser Interferometer Space Antenna. For the first time, we consistently compute the generation of gravitational waves from extreme-mass ratio inspirals (stellar compact objects into supermassive black holes) in a well-motivated alternative theory of gravity, that to date remains weakly constrained by double binary pulsar observations. The theory we concentrate on is Chern-Simons (CS) modified gravity, a 4-D, effective theory that is motivated both from string theory and loop-quantum gravity, and which enhances the Einstein-Hilbert action through the addition of a dynamical scalar field and the parity-violating Pontryagin density. We show that although point particles continue to follow geodesics in the modified theory, the background about which they inspiral is a modification to the Kerr metric, which imprints a CS correction on the gravitational waves emitted. CS modified gravitational waves are sufficiently different from the General Relativistic expectation that they lead to significant dephasing after 3 weeks of evolution, but such dephasing will probably not prevent detection of these signals, but instead lead to a systematic error in the determination of parameters. We end with a study of radiation-reaction in the modified theory and show that, to leading-order, energy-momentum emission is not CS modified, except possibly for the subdominant effect of scalar-field emission. The inclusion of radiation-reaction will allow for tests of CS modified gravity with space-borne detectors that might be two orders of magnitude larger than current binary pulsar bounds.

  7. Toxicity assessment of industrial chemicals and airborne contaminants: transition from in vivo to in vitro test methods: a review.

    Science.gov (United States)

    Bakand, S; Winder, C; Khalil, C; Hayes, A

    2005-12-01

    Exposure to occupational and environmental contaminants is a major contributor to human health problems. Inhalation of gases, vapors, aerosols, and mixtures of these can cause a wide range of adverse health effects, ranging from simple irritation to systemic diseases. Despite significant achievements in the risk assessment of chemicals, the toxicological database, particularly for industrial chemicals, remains limited. Considering there are approximately 80,000 chemicals in commerce, and an extremely large number of chemical mixtures, in vivo testing of this large number is unachievable from both economical and practical perspectives. While in vitro methods are capable of rapidly providing toxicity information, regulatory agencies in general are still cautious about the replacement of whole-animal methods with new in vitro techniques. Although studying the toxic effects of inhaled chemicals is a complex subject, recent studies demonstrate that in vitro methods may have significant potential for assessing the toxicity of airborne contaminants. In this review, current toxicity test methods for risk evaluation of industrial chemicals and airborne contaminants are presented. To evaluate the potential applications of in vitro methods for studying respiratory toxicity, more recent models developed for toxicity testing of airborne contaminants are discussed.

  8. First test results of the airborne dispersive pushbroom imaging spectrometer APEX

    Science.gov (United States)

    Meuleman, K.; Itten, K.; Schaepman, M.

    2009-04-01

    APEX, ESA-Prodex "Airborne Prism Experiment" comprises the development of an airborne dispersive pushbroom imaging spectrometer and has originally been designed as flexible hyperspectral mission simulator and calibrator for existing and upcoming or planned future space missions. The APEX project is co-funded by Switzerland and Belgium and built by a Belgian-Swiss industrial team under the prime RUAG Aerospace (CH), responsible for the total system and the mechanical components, OIP (Oudenaarde, BE) contributing the spectrometer, and Netcetera (Zurich, CH) being responsible for the electronics. RSL (University of Zurich, CH) acts as scientific PI together with the Co-PI VITO (Mol, BE). The APEX sensor is operating between 380 nm and 2500 nm in more than 300 freely configurable bands (up to 512 bands in full spectral mode), by means of two dispersive spectrometer channels. 1000 pixels across track and a total field of view of 28° define the ground pixel size (e.g. 2,5 m from 5000 m AGL). A stabilized platform (Leica PAV-30) reduces major geometric distortions due to aircraft instabilities while a GPS/IMU system (Applanix PosAV 410) measures continuously the sensors' position and orientation allowing direct georeferencing of the acquired data . The system is currently is phase D, the calibration and test phase, and first testflights have been performed on a Do-228 in cooperation of DLR while the acquired data is currently under evaluation. Discussions are ongoing to fly APEX on the new DLR High Altitude Research Aircraft (HALO) as well. The system is currently in phase D, the calibration and test phase, and will deliver first scientific data to users by mid 2009. The APEX processing and archiving facility (PAF) is hosted by VITO in the APEX Operations Center (AOC) at Mol, Belgium . A specific level 0-1 processing software module producing uniform, radiometrically calibrated data has been developed by RSL and is integrated into the PAF by VITO. An APEX Calibration

  9. Testing modified gravity at large distances with the HI Nearby Galaxy Survey's rotation curves

    Science.gov (United States)

    Mastache, Jorge; Cervantes-Cota, Jorge L.; de la Macorra, Axel

    2013-03-01

    Recently a new—quantum motivated—theory of gravity has been proposed that modifies the standard Newtonian potential at large distances when spherical symmetry is considered. Accordingly, Newtonian gravity is altered by adding an extra Rindler acceleration term that has to be phenomenologically determined. Here we consider a standard and a power-law generalization of the Rindler modified Newtonian potential. The new terms in the gravitational potential are hypothesized to play the role of dark matter in galaxies. Our galactic model includes the mass of the integrated gas, and stars for which we consider three stellar mass functions (Kroupa, diet-Salpeter, and free mass model). We test this idea by fitting rotation curves of seventeen low surface brightness galaxies from the HI Nearby Galaxy Survey (THINGS). We find that the Rindler parameters do not perform a suitable fit to the rotation curves in comparison to standard dark matter profiles (Navarro-Frenk-White and Burkert) and, in addition, the computed parameters of the Rindler gravity show a high spread, posing the model as a nonacceptable alternative to dark matter.

  10. Ultra faint dwarf galaxies: an arena for testing dark matter versus modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Weikang; Ishak, Mustapha, E-mail: wxl123830@utdallas.edu, E-mail: mishak@utdallas.edu [Department of Physics, University of Texas at Dallas, Richardson, TX 75083 (United States)

    2016-10-01

    The scenario consistent with a wealth of observations for the missing mass problem is that of weakly interacting dark matter particles. However, arguments or proposals for a Newtonian or relativistic modified gravity scenario continue to be made. A distinguishing characteristic between the two scenarios is that dark matter particles can produce a gravitational effect, in principle, without the need of baryons while this is not the case for the modified gravity scenario where such an effect must be correlated with the amount of baryonic matter. We consider here ultra-faint dwarf (UFD) galaxies as a promising arena to test the two scenarios based on the above assertion. We compare the correlation of the luminosity with the velocity dispersion between samples of UFD and non-UFD galaxies, finding a significant loss of correlation for UFD galaxies. For example, we find for 28 non-UFD galaxies a strong correlation coefficient of −0.688 which drops to −0.077 for the 23 UFD galaxies. Incoming and future data will determine whether the observed stochasticity for UFD galaxies is physical or due to systematics in the data. Such a loss of correlation (if it is to persist) is possible and consistent with the dark matter scenario for UFD galaxies but would constitute a new challenge for the modified gravity scenario.

  11. Gravity and magnetic data of Fortymile Wash, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    Ponce, D.A.; Kohrn, S.B.; Waddell, S.

    1992-01-01

    Gravity and ground magnetic data collected along six traverses across Fortymile Wash, in the southwest quadrant of the Nevada Test Site suggest that there are no significant vertical offsets below Fortymile Wash. The largest gravity and magnetic anomaly, in the vicinity of Fortymile Wash, is produced by the Paintbrush fault, on the west flank of Fran Ridge. Inferred vertical offset is about 250 ± 60 m (800 ± 200 ft). Geophysical data indicate that the fault is about 300 m (1,000 ft) east of its mapped, but concealed location. North of Busted Butte, near Fran Ridge, geophysical data do not preclude the existence of small vertical offsets bounding Fortymile Wash. However, gravity and magnetic profiles south of Busted Butte show little correlation to those to the north and suggest that vertical offsets, comparable in size to the Paintbrush fault, are not present. Density profiling, a technique used to determine the average density of small topographic features, suggests that the density of near-surface material in the vicinity of Fortymile Wash is 1.80 to 2.00 g/cm 3

  12. The current ability to test theories of gravity with black hole shadows

    Science.gov (United States)

    Mizuno, Yosuke; Younsi, Ziri; Fromm, Christian M.; Porth, Oliver; De Laurentis, Mariafelicia; Olivares, Hector; Falcke, Heino; Kramer, Michael; Rezzolla, Luciano

    2018-04-01

    Our Galactic Centre, Sagittarius A*, is believed to harbour a supermassive black hole, as suggested by observations tracking individual orbiting stars1,2. Upcoming submillimetre very-long baseline interferometry images of Sagittarius A* carried out by the Event Horizon Telescope collaboration (EHTC)3,4 are expected to provide critical evidence for the existence of this supermassive black hole5,6. We assess our present ability to use EHTC images to determine whether they correspond to a Kerr black hole as predicted by Einstein's theory of general relativity or to a black hole in alternative theories of gravity. To this end, we perform general-relativistic magnetohydrodynamical simulations and use general-relativistic radiative-transfer calculations to generate synthetic shadow images of a magnetized accretion flow onto a Kerr black hole. In addition, we perform these simulations and calculations for a dilaton black hole, which we take as a representative solution of an alternative theory of gravity. Adopting the very-long baseline interferometry configuration from the 2017 EHTC campaign, we find that it could be extremely difficult to distinguish between black holes from different theories of gravity, thus highlighting that great caution is needed when interpreting black hole images as tests of general relativity.

  13. The Santiago-Harvard-Edinburgh-Durham void comparison - I. SHEDding light on chameleon gravity tests

    Science.gov (United States)

    Cautun, Marius; Paillas, Enrique; Cai, Yan-Chuan; Bose, Sownak; Armijo, Joaquin; Li, Baojiu; Padilla, Nelson

    2018-05-01

    We present a systematic comparison of several existing and new void-finding algorithms, focusing on their potential power to test a particular class of modified gravity models - chameleon f(R) gravity. These models deviate from standard general relativity (GR) more strongly in low-density regions and thus voids are a promising venue to test them. We use halo occupation distribution (HOD) prescriptions to populate haloes with galaxies, and tune the HOD parameters such that the galaxy two-point correlation functions are the same in both f(R) and GR models. We identify both three-dimensional (3D) voids and two-dimensional (2D) underdensities in the plane of the sky to find the same void abundance and void galaxy number density profiles across all models, which suggests that they do not contain much information beyond galaxy clustering. However, the underlying void dark matter density profiles are significantly different, with f(R) voids being more underdense than GR ones, which leads to f(R) voids having a larger tangential shear signal than their GR analogues. We investigate the potential of each void finder to test f(R) models with near-future lensing surveys such as EUCLID and LSST. The 2D voids have the largest power to probe f(R) gravity, with an LSST analysis of tunnel (which is a new type of 2D underdensity introduced here) lensing distinguishing at 80 and 11σ (statistical error) f(R) models with parameters, |fR0| = 10-5 and 10-6, from GR.

  14. Low-gravity homogenization and solidification of aluminum antimonide. [Apollo-Soyuz test project

    Science.gov (United States)

    Ang, C.-Y.; Lacy, L. L.

    1976-01-01

    The III-V semiconducting compound AlSb shows promise as a highly efficient solar cell material, but it has not been commercially exploited because of difficulties in compound synthesis. Liquid state homogenization and solidification of AlSb were carried out in the Apollo-Soyuz Test Project Experiment MA-044 in the hope that compositional homogeneity would be improved by negating the large density difference between the two constituents. Post-flight analysis and comparative characterization of the space-processed and ground-processed samples indicate that there are major homogeneity improvements in the low-gravity solidified material.

  15. Tonopah Test Range Air Monitoring: CY2012 Meteorological, Radiological, and Airborne Particulate Observations

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A; Nikolich, George; Shadel, Craig; McCurdy, Greg; Miller, Julianne J

    2013-07-01

    In 1963, the Atomic Energy Commission (AEC), predecessor to the US Department of Energy (DOE), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range (NAFR)). Operation Roller Coaster consisted of four tests in which chemical explosions were detonated in the presence of nuclear devices to assess the dispersal of radionuclides and evaluate the effectiveness of storage structures to contain the ejected radionuclides. These tests resulted in dispersal of plutonium over the ground surface downwind of the test ground zero. Three tests, Clean Slate 1, 2, and 3, were conducted on the TTR in Cactus Flat; the fourth, Double Tracks, was conducted in Stonewall Flat on the NTTR. DOE is working to clean up and close all four sites. Substantial cleaned up has been accomplished at Double Tracks and Clean Slate 1. Cleanup of Clean Slate 2 and 3 is on the DOE planning horizon for some time in the next several years. The Desert Research Institute installed two monitoring stations, number 400 at the Sandia National Laboratories Range Operations Center and number 401 at Clean Slate 3, in 2008 and a third monitoring station, number 402 at Clean Slate 1, in 2011 to measure radiological, meteorological, and dust conditions. The primary objectives of the data collection and analysis effort are to (1) monitor the concentration of radiological parameters in dust particles suspended in air, (2) determine whether winds are re-distributing radionuclides or contaminated soil material, (3) evaluate the controlling meteorological conditions if wind transport is occurring, and (4) measure ancillary radiological, meteorological, and environmental parameters that might provide insight to the above assessments. The following observations are based on data collected during CY2012. The mean annual concentration of gross alpha and gross beta is highest at Station 400 and lowest at Station

  16. NASA SMD Airborne Science Capabilities for Development and Testing of New Instruments

    Science.gov (United States)

    Fladeland, Matthew

    2015-01-01

    The SMD NASA Airborne Science Program operates and maintains a fleet of highly modified aircraft to support instrument development, satellite instrument calibration, data product validation and earth science process studies. This poster will provide an overview of aircraft available to NASA researchers including performance specifications and modifications for instrument support, processes for requesting aircraft time and developing cost estimates for proposals, and policies and procedures required to ensure safety of flight.

  17. Results and Lessons Learned from Performance Testing of Humans in Spacesuits in Simulated Reduced Gravity

    Science.gov (United States)

    Chappell, Steven P.; Norcross, Jason R.; Gernhardt, Michael L.

    2009-01-01

    NASA's Constellation Program has plans to return to the Moon within the next 10 years. Although reaching the Moon during the Apollo Program was a remarkable human engineering achievement, fewer than 20 extravehicular activities (EVAs) were performed. Current projections indicate that the next lunar exploration program will require thousands of EVAs, which will require spacesuits that are better optimized for human performance. Limited mobility and dexterity, and the position of the center of gravity (CG) are a few of many features of the Apollo suit that required significant crew compensation to accomplish the objectives. Development of a new EVA suit system will ideally result in performance close to or better than that in shirtsleeves at 1 G, i.e., in "a suit that is a pleasure to work in, one that you would want to go out and explore in on your day off." Unlike the Shuttle program, in which only a fraction of the crew perform EVA, the Constellation program will require that all crewmembers be able to perform EVA. As a result, suits must be built to accommodate and optimize performance for a larger range of crew anthropometry, strength, and endurance. To address these concerns, NASA has begun a series of tests to better understand the factors affecting human performance and how to utilize various lunar gravity simulation environments available for testing.

  18. Theoretical frameworks for testing relativistic gravity. IV - A compendium of metric theories of gravity and their post-Newtonian limits.

    Science.gov (United States)

    Ni, W.-T.

    1972-01-01

    Metric theories of gravity are compiled and classified according to the types of gravitational fields they contain, and the modes of interaction among those fields. The gravitation theories considered are classified as (1) general relativity, (2) scalar-tensor theories, (3) conformally flat theories, and (4) stratified theories with conformally flat space slices. The post-Newtonian limit of each theory is constructed and its Parametrized Post-Newtonian (PPN) values are obtained by comparing it with Will's version of the formalism. Results obtained here, when combined with experimental data and with recent work by Nordtvedt and Will and by Ni, show that, of all theories thus far examined by our group, the only currently viable ones are general relativity, the Bergmann-Wagoner scalar-tensor theory and its special cases (Nordtvedt; Brans-Dicke-Jordan), and a recent, new vector-tensor theory by Nordtvedt, Hellings, and Will.

  19. Test of Relativistic Gravity for Propulsion at the Large Hadron Collider

    Science.gov (United States)

    Felber, Franklin

    2010-01-01

    A design is presented of a laboratory experiment that could test the suitability of relativistic gravity for propulsion of spacecraft to relativistic speeds. An exact time-dependent solution of Einstein's gravitational field equation confirms that even the weak field of a mass moving at relativistic speeds could serve as a driver to accelerate a much lighter payload from rest to a good fraction of the speed of light. The time-dependent field of ultrarelativistic particles in a collider ring is calculated. An experiment is proposed as the first test of the predictions of general relativity in the ultrarelativistic limit by measuring the repulsive gravitational field of bunches of protons in the Large Hadron Collider (LHC). The estimated `antigravity beam' signal strength at a resonant detector of each proton bunch is 3 nm/s2 for 2 ns during each revolution of the LHC. This experiment can be performed off-line, without interfering with the normal operations of the LHC.

  20. Testing theories of gravity and supergravity with inflation and observations of the cosmic microwave background

    Science.gov (United States)

    Chakravarty, G. K.; Mohanty, S.; Lambiase, G.

    theories when applied to inflation (a rapid expansion of early universe in which primordial gravitational waves might be generated and might still be detectable by the imprint they left or by the ripples that persist today) can have distinct signatures in the Cosmic Microwave Background radiation temperature and polarization anisotropies. We give a review of ΛCDM cosmology and survey the theories of gravity beyond Einstein’s General Relativity, specially which arise from SUGRA, and study the consequences of these theories in the context of inflation and put bounds on the theories and the parameters therein from the observational experiments like PLANCK, Keck/BICEP, etc. The possibility of testing these theories in the near future in CMB observations and new data coming from colliders like the LHC, provides an unique opportunity for constructing verifiable models of particle physics and General Relativity.

  1. Gravity measurement, processing and evaluation: Test cases de Peel and South Limburg

    Science.gov (United States)

    Nohlmans, Ron

    1990-05-01

    A general overview of the process of the measurement and the adjustment of a gravity network and the computation of some output parameters of gravimetry, gravity values, gravity anomalies and mean block anomalies, is given. An overview of developments in gravimetry, globally and in the Netherlands, until now is given. The basic theory of relative gravity measurements is studied and a description of the most commonly used instrument, the LaCoste and Romberg gravimeter is given. The surveys done in the scope of this study are descibed. A more detailed impression of the adjustment procedure and the results of the adjustment are given. A closer look is taken at the more geophysical side of gravimetry: gravity reduction, the computation of anomalies and the correlation with elevation. The interpolation of gravity and the covariance of gravity anomalies are addressed.

  2. The development of an airborne information management system for flight test

    Science.gov (United States)

    Bever, Glenn A.

    1992-01-01

    An airborne information management system is being developed at the NASA Dryden Flight Research Facility. This system will improve the state of the art in management data acquisition on-board research aircraft. The design centers around highly distributable, high-speed microprocessors that allow data compression, digital filtering, and real-time analysis. This paper describes the areas of applicability, approach to developing the system, potential for trouble areas, and reasons for this development activity. System architecture (including the salient points of what makes it unique), design philosophy, and tradeoff issues are also discussed.

  3. The emission of Gamma Ray Bursts as a test-bed for modified gravity

    Directory of Open Access Journals (Sweden)

    S. Capozziello

    2015-11-01

    Full Text Available The extreme physical conditions of Gamma Ray Bursts can constitute a useful observational laboratory to test theories of gravity where very high curvature regimes are involved. Here we propose a sort of curvature engine capable, in principle, of explaining the huge energy emission of Gamma Ray Bursts. Specifically, we investigate the emission of radiation by charged particles non-minimally coupled to the gravitational background where higher order curvature invariants are present. The coupling gives rise to an additional force inducing a non-geodesic motion of particles. This fact allows a strong emission of radiation by gravitationally accelerated particles. As we will show with some specific model, the energy emission is of the same order of magnitude of that characterizing the Gamma Ray Burst physics. Alternatively, strong curvature regimes can be considered as a natural mechanism for the generation of highly energetic astrophysical events. Possible applications to cosmology are discussed.

  4. Testing of a Spray-Bar Zero Gravity Cryogenic Vent System for Upper Stages

    Science.gov (United States)

    Lak, Tibor; Flachbart, Robin; Nguyen, Han; Martin, James

    1999-01-01

    The capability to vent in zero gravity without resettling is a fundamental technology need that involves practically all uses of subcritical cryogenics in space. Venting without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule- Thomson (J-T) valve to extract then-nal energy from the propellant. In a cooperative effort, Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (N4HTB) was used to test a unique "spray bar" TVS system developed by Boeing. A schematic of this system is included in Figure 1. The system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it radially into the tank liquid, ullage, and exposed tank surfaces. When energy extraction is required, a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the spray bar heat exchanger element, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. Figure 2 is a plot of ullage pressure (P4) and liquid vapor pressure (PSAI) versus time. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point, the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating boil-off losses. The primary advantage of the

  5. Gamma-Ray, Cosmic Ray and Neutrino Tests of Lorentz Invariance and Quantum Gravity Models

    Science.gov (United States)

    Stecker, Floyd

    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 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 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) to the amount of LIV of at a proton 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.

  6. Gravity Probe B: final results of a space experiment to test general relativity.

    Science.gov (United States)

    Everitt, C W F; DeBra, D B; Parkinson, B W; Turneaure, J P; Conklin, J W; Heifetz, M I; Keiser, G M; Silbergleit, A S; Holmes, T; Kolodziejczak, J; Al-Meshari, M; Mester, J C; Muhlfelder, B; Solomonik, V G; Stahl, K; Worden, P W; Bencze, W; Buchman, S; Clarke, B; Al-Jadaan, A; Al-Jibreen, H; Li, J; Lipa, J A; Lockhart, J M; Al-Suwaidan, B; Taber, M; Wang, S

    2011-06-03

    Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein's theory of general relativity (GR), the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection started 28 August 2004 and ended 14 August 2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6601.8±18.3  mas/yr and a frame-dragging drift rate of -37.2±7.2  mas/yr, to be compared with the GR predictions of -6606.1  mas/yr and -39.2  mas/yr, respectively ("mas" is milliarcsecond; 1  mas=4.848×10(-9)  rad).

  7. Astrophysical Tests of Kinematical Conformal Cosmology in Fourth-Order Conformal Weyl Gravity

    Directory of Open Access Journals (Sweden)

    Gabriele U. Varieschi

    2014-12-01

    Full Text Available In this work we analyze kinematical conformal cosmology (KCC, an alternative cosmological model based on conformal Weyl gravity (CG, and test it against current type Ia supernova (SNIa luminosity data and other astrophysical observations. Expanding upon previous work on the subject, we revise the analysis of SNIa data, confirming that KCC can explain the evidence for an accelerating expansion of the Universe without using dark energy or other exotic components. We obtain an independent evaluation of the Hubble constant, H0 = 67:53 kms-1 Mpc-1, very close to the current best estimates. The main KCC and CG parameters are re-evaluated and their revised values are found to be close to previous estimates. We also show that available data for the Hubble parameter as a function of redshift can be fitted using KCC and that this model does not suffer from any apparent age problem. Overall,

  8. Tests of Low Scale Gravity via Gauge Boson Pair Production in γγ Collisions

    International Nuclear Information System (INIS)

    Rizzo, Thomas G.

    1999-01-01

    Arkani-Hamed, Dimopoulos and Dvali have recently proposed that gravity may become strong at energies near 1 TeV thus removing the hierarchy problem. This scenario can be tested in several ways at present and future colliders. In this paper we examine the exchange of towers of Kaluza-Klein gravitons and their influence on the production of pairs of massive gauge bosons in γγ collisions. These tower exchanges are shown to lead to a new dimension-8 operator that can significant alter the Standard Model expectations for these processes. The role of polarization for both the initial state photons and the final state gauge bosons in improving sensitivity to graviton exchange is emphasized. We find that the discovery reach for graviton tower exchange in the γγ r a rrow W + W - channel to be significantly greater than for any other process so far examined

  9. Airborne Evaluation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — AFRL's Airborne Evaluation Facility (AEF) utilizes Air Force Aero Club resources to conduct test and evaluation of a variety of equipment and concepts. Twin engine...

  10. Moving base Gravity Gradiometer Survey System (GGSS) program

    Science.gov (United States)

    Pfohl, Louis; Rusnak, Walter; Jircitano, Albert; Grierson, Andrew

    1988-04-01

    The GGSS program began in early 1983 with the objective of delivering a landmobile and airborne system capable of fast, accurate, and economical gravity gradient surveys of large areas anywhere in the world. The objective included the development and use of post-mission data reduction software to process the survey data into solutions for the gravity disturbance vector components (north, east and vertical). This document describes the GGSS equipment hardware and software, integration and lab test procedures and results, and airborne and land survey procedures and results. Included are discussions on test strategies, post-mission data reduction algorithms, and the data reduction processing experience. Perspectives and conclusions are drawn from the results.

  11. Design and testing of a unique randomized gravity, continuous flow bioreactor

    Science.gov (United States)

    Lassiter, Carroll B.

    1993-01-01

    A rotating, null gravity simulator, or Couette bioreactor was successfully used for the culture of mammalian cells in a simulated microgravity environment. Two limited studies using Lipomyces starkeyi and Streptomyces clavuligerus were also conducted under conditions of simulated weightlessness. Although these studies with microorganisms showed promising preliminary results, oxygen limitations presented significant limitations in studying the biochemical and cultural characteristics of these cell types. Microbial cell systems such as bacteria and yeast promise significant potential as investigative models to study the effects of microgravity on membrane transport, as well as substrate induction of inactive enzyme systems. Additionally, the smaller size of the microorganisms should further reduce the gravity induced oscillatory particle motion and thereby improve the microgravity simulation on earth. Focus is on the unique conceptual design, and subsequent development of a rotating bioreactor that is compatible with the culture and investigation of microgravity effects on microbial systems. The new reactor design will allow testing of highly aerobic cell types under simulated microgravity conditions. The described reactor affords a mechanism for investigating the long term effects of reduced gravity on cellular respiration, membrane transfer, ion exchange, and substrate conversions. It offers the capability of dynamically altering nutrients, oxygenation, pH, carbon dioxide, and substrate concentration without disturbing the microgravity simulation, or Couette flow, of the reactor. All progeny of the original cell inoculum may be acclimated to the simulated microgravity in the absence of a substrate or nutrient. The reactor has the promise of allowing scientists to probe the long term effects of weightlessness on cell interactions in plants, bacteria, yeast, and fungi. The reactor is designed to have a flow field growth chamber with uniform shear stress, yet transfer

  12. Mutagenic and recombinagenic activity of airborne particulates, PM10 and TSP, organic extracts in the Drosophila wing-spot test

    International Nuclear Information System (INIS)

    Rodrigues Dihl, Rafael; Grazielli Azevedo da Silva, Carla; Souza do Amaral, Viviane; Reguly, Maria Luiza; Rodrigues de Andrade, Heloisa Helena

    2008-01-01

    The genotoxicity associated with air pollution in the city of Canoas, Rio Grande do Sul (Brazil), was assessed in November (spring) and January (summer). We applied the somatic mutation and recombination test (SMART) in Drosophila melanogaster in its standard version with normal bioactivation (ST) and in its variant with increased cytochrome P450-dependent biotransformation capacity (HB). The data indicated the genotoxicity of TSP and PM10 collected in November, in both ST and HB crosses. The genotoxic activity of the PM10 material in the spring sample was exclusively associated with the induction of mitotic recombination, whereas the TSP genetic toxicity was due to both recombinational as well as point and/or chromosomal mutation events. Considering PM10 collected in January, a positive response-100% (17.10 m 3 /ml) concentration-was observed in the HB cross, which was not detected in the ST cross. - Drosophila Wing-Spot Test can be used for detection of airborne particulates mutagenesis

  13. Formalism for testing theories of gravity using lensing by compact objects. II. Probing post-post-Newtonian metrics

    International Nuclear Information System (INIS)

    Keeton, Charles R.; Petters, A.O.

    2006-01-01

    We study gravitational lensing by compact objects in gravity theories that can be written in a post-post-Newtonian (PPN) framework: i.e., the metric is static and spherically symmetric, and can be written as a Taylor series in m /r, where m is the gravitational radius of the compact object. Working invariantly, we compute corrections to standard weak-deflection lensing observables at first and second order in the perturbation parameter ε=θ/θ E , where θ is the angular gravitational radius and θ E is the angular Einstein ring radius of the lens. We show that the first-order corrections to the total magnification and centroid position vanish universally for gravity theories that can be written in the PPN framework. This arises from some surprising, fundamental relations among the lensing observables in PPN gravity models. We derive these relations for the image positions, magnifications, and time delays. A deep consequence is that any violation of the universal relations would signal the need for a gravity model outside the PPN framework (provided that some basic assumptions hold). In practical terms, the relations will guide observational programs to test general relativity, modified gravity theories, and possibly the cosmic censorship conjecture. We use the new relations to identify lensing observables that are accessible to current or near-future technology, and to find combinations of observables that are most useful for probing the spacetime metric. We give explicit applications to the galactic black hole, microlensing, and the binary pulsar J0737-3039

  14. Are we close to putting the anomalous perihelion precessions from Verlinde's emergent gravity to the test?

    Science.gov (United States)

    Iorio, Lorenzo

    2017-03-01

    In the framework of the emergent gravity scenario by Verlinde, it was recently observed by Liu and Prokopec that, among other things, an anomalous pericenter precession would affect the orbital motion of a test particle orbiting an isolated central body. Here, it is shown that, if it were real, its expected magnitude for the inner planets of the Solar System would be at the same level of the present-day accuracy in constraining any possible deviations from their standard perihelion precessions as inferred from long data records spanning about the last century. The most favorable situation for testing the Verlinde-type precession seems to occur for Mars. Indeed, according to recent versions of the EPM and INPOP planetary ephemerides, non-standard perihelion precessions, of whatsoever physical origin, which are larger than some ≈ 0.02-0.11 milliarcseconds per century are not admissible, while the putative precession predicted by Liu and Prokopec amounts to 0.09 milliarcseconds per century. Other potentially interesting astronomical and astrophysical scenarios like, e.g., the Earth's LAGEOS II artificial satellite, the double pulsar system PSR J0737-3039A/B and the S-stars orbiting the Supermassive Black Hole in Sgr A^* are, instead, not viable because of the excessive smallness of the predicted precessions for them.

  15. Timing system design and tests for the Gravity Probe B relativity mission

    International Nuclear Information System (INIS)

    Li, J; Keiser, G M; Ohshima, Y; Shestople, P; Lockhart, J M

    2015-01-01

    In this paper, we discuss the timing system design and tests for the NASA/Stanford Gravity Probe B (GP-B) relativity mission. The primary clock of GP-B, called the 16f o clock, was an oven-controlled crystal oscillator that produced a 16.368 MHz master frequency 3 . The 16f o clock and the 10 Hz data strobe, which was divided down from the 16f o clock, provided clock signals to all GP-B components and synchronized the data collection, transmission, and processing. The sampled data of science signals were stamped with the vehicle time, a counter of the 10 Hz data strobe. The time latency between the time of data sampling and the stamped vehicle time was compensated in the ground data processing. Two redundant global positioning system receivers onboard the GP-B satellite supplied an external reference for time transfer between the vehicle time and coordinated universal time (UTC), and the time conversion was established in the ground preprocessing of the telemetry timing data. The space flight operation showed that the error of time conversion between the vehicle time and UTC was less than 2 μs. Considering that the constant timing offsets were compensated in the ground processing of the GP-B science data, the time latency between the effective sampling time of GP-B science signals and the stamped vehicle time was verified to within 1 ms in the ground tests. (paper)

  16. The gravity field and GGOS

    DEFF Research Database (Denmark)

    Forsberg, René; Sideris, M.G.; Shum, C.K.

    2005-01-01

    The gravity field of the earth is a natural element of the Global Geodetic Observing System (GGOS). Gravity field quantities are like spatial geodetic observations of potential very high accuracy, with measurements, currently at part-per-billion (ppb) accuracy, but gravity field quantities are also...... unique as they can be globally represented by harmonic functions (long-wavelength geopotential model primarily from satellite gravity field missions), or based on point sampling (airborne and in situ absolute and superconducting gravimetry). From a GGOS global perspective, one of the main challenges...... is to ensure the consistency of the global and regional geopotential and geoid models, and the temporal changes of the gravity field at large spatial scales. The International Gravity Field Service, an umbrella "level-2" IAG service (incorporating the International Gravity Bureau, International Geoid Service...

  17. Test of Gravity on Large Scales with Weak Gravitational Lensing and Clustering Measurements of SDSS Luminous Red Galaxies

    Science.gov (United States)

    Reyes, Reinabelle; Mandelbaum, R.; Seljak, U.; Gunn, J.; Lombriser, L.

    2009-01-01

    We perform a test of gravity on large scales (5-50 Mpc/h) using 70,000 luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) DR7 with redshifts 0.16gravity and is largely independent of galaxy bias and sigma_8. In particular, E_G is sensitive to the relation between the spatial and temporal scalar perturbations in the space-time metric. While these two potentials are equivalent in concordance cosmology (GR+LCDM) in the absence of anisotropic stress, they are not equivalent in alternative theories of gravity in general, so that different models make different predictions for E_G. We find E_G=0.37±0.05 averaged over scales 5gravity theories, including f(R), DGP, and TeVeS. This work serves as a proof of concept for the application of this test in future galaxy surveys such as LSST, for which a very high signal-to-noise measurement will be possible.

  18. Results on the gravity of quantum Fermi pressure of localized matter: A new test of general relativity

    International Nuclear Information System (INIS)

    Unnikrishnan, C.S.; Gillies, G.T.

    2006-01-01

    Recently Ehlers, Ozsvath, and Schucking discussed whether pressure contributes to active gravitational mass as required by general relativity. They pointed out that there is no experimental information on this available, though precision measurement of the gravitational constant should provide a test of this foundational aspect of gravity. We had used a similar argument earlier to test the contribution of leptons to the active gravitational mass. In this paper we use the result from the Zuerich gravitational constant experiment to provide the first adequate experimental input regarding the active gravitational mass of Fermi pressure. Apart from confirming the equality of the passive and active gravitational roles of the pressure term in general relativity within an accuracy of 5%, our results are consistent with the theoretical expectation of the cancellation of the gravity of pressure by the gravity of the surface tension of confined matter. This result on the active gravitational mass of the quantum zero-point Fermi pressure in the atomic nucleus is also interesting from the point of view of studying the interplay between quantum physics and classical gravity

  19. Test of gauge invariance and unitarity of the quantized Einstein theory of gravity

    International Nuclear Information System (INIS)

    Hsu, J.P.; Underwood, J.A.

    1975-01-01

    Explicit calculations at the 1-loop level verify that the usual quantized Einstein theory of gravity is indeed gauge independent and unitary for all values of the gauge parameter α. This lends nontrivial support to a general formal proof

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

    Science.gov (United States)

    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.

  1. Tests Results of the Electrostatic Accelerometer Flight Models for Gravity Recovery and Climate Experiment Follow-On Mission (GRACE FO)

    Science.gov (United States)

    Perrot, E.; Boulanger, D.; Christophe, B.; Foulon, B.; Lebat, V.; Huynh, P. A.; Liorzou, F.

    2015-12-01

    The GRACE FO mission, led by the JPL (Jet Propulsion Laboratory), is an Earth-orbiting gravity mission, continuation of the GRACE mission, which will produce an accurate model of the Earth's gravity field variation providing global climatic data during five years at least. The mission involves two satellites in a loosely controlled tandem formation, with a micro-wave link measuring the inter-satellites distance variation. Earth's mass distribution non-uniformities cause variations of the inter-satellite distance. This variation is measured to recover gravity, after subtracting the non-gravitational contributors, as the residual drag. ONERA (the French Aerospace Lab) is developing, manufacturing and testing electrostatic accelerometers measuring this residual drag applied on the satellites. The accelerometer is composed of two main parts: the Sensor Unit (including the Sensor Unit Mechanics - SUM - and the Front-End Electronic Unit - FEEU) and the Interface Control Unit - ICU. In the Accelerometer Core, located in the Sensor Unit Mechanics, the proof mass is levitated and maintained at the center of an electrode cage by electrostatic forces. Thus, any drag acceleration applied on the satellite involves a variation on the servo-controlled electrostatic suspension of the mass. The voltage on the electrodes providing this electrostatic force is the output measurement of the accelerometer. The impact of the accelerometer defaults (geometry, electronic and parasitic forces) leads to bias, misalignment and scale factor error, non-linearity and noise. Some of these accelerometer defaults are characterized by tests with micro-gravity pendulum bench on ground and with drops in ZARM catapult. The Critical Design Review was achieved successfully on September 2014. The Engineering Model (EM) was integrated and tested successfully, with ground levitation, drops, Electromagnetic Compatibility and thermal vacuum. The integration of the two Flight Models was done on July 2015. The

  2. Equation of Motion of a Mass Point in Gravitational Field and Classical Tests of Gauge Theory of Gravity

    International Nuclear Information System (INIS)

    Wu Ning; Zhang Dahua

    2007-01-01

    A systematic method is developed to study the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the traditional Schwarzschild solution. Combining the principle of gauge covariance and Newton's second law of motion, the equation of motion of a mass point in gravitational field is deduced. Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field, we can discuss classical tests of gauge theory of gravity, including the deflection of light by the sun, the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun. It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity.

  3. Standard Test Method for Water Absorption, Bulk Density, Apparent Porosity, and Apparent Specific Gravity of Fired Whiteware Products

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method covers procedures for determining water absorption, bulk density, apparent porosity, and apparent specific gravity of fired unglazed whiteware products. 1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Development and Preliminary Tests of an Open-Path Airborne Diode Laser Absorption Instrument for Carbon Dioxide

    Science.gov (United States)

    Diskin, Glenn S.; DiGangi, Joshua P.; Yang, Melissa; Slate, Thomas A.; Rana, Mario

    2015-01-01

    Carbon dioxide (CO2) is well known for its importance as an atmospheric greenhouse gas, with many sources and sinks around the globe. Understanding the fluxes of carbon into and out of the atmosphere is a complex and daunting challenge. One tool applied by scientists to measure the vertical flux of CO2 near the surface uses the eddy covariance technique, most often from towers but also from aircraft flying specific patterns over the study area. In this technique, variations of constituents of interest are correlated with fluctuations in the local vertical wind velocity. Measurement requirements are stringent, particularly with regard to precision, sensitivity to small changes, and temporal sampling rate. In addition, many aircraft have limited payload capability, so instrument size, weight, and power consumption are also important considerations. We report on the development and preliminary application of an airborne sensor for the measurement of atmospheric CO2. The instrument, modeled on the successful DLH (Diode Laser Hygrometer) series of instruments, has been tested in the laboratory and on the NASA DC-8 aircraft. Performance parameters such as accuracy, precision, sensitivity, specificity, and temporal response are discussed in the context of typical atmospheric variability and suitability for flux measurement applications. On-aircraft, in-flight data have been obtained and are discussed as well. Performance of the instrument has been promising, and continued flight testing is planned during 2016.

  5. Mutagenic and recombinagenic activity of airborne particulates, PM10 and TSP, organic extracts in the Drosophila wing-spot test

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues Dihl, Rafael [Programa de Pos Graduacao em Genetica e Biologia Molecular (PPGBM), Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Grazielli Azevedo da Silva, Carla [Instituto de Quimica, Departamento de Quimica Organica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Souza do Amaral, Viviane; Reguly, Maria Luiza [Laboratorio de Diagnostico da Toxicidade Genetica (TOXIGEN), Programa de Pos Graduacao em Genetica e Toxicologia Aplicada (PPGGTA), Universidade Luterana do Brasil - ULBRA, Avenida Farroupilha 8001, 92420280 Canoas, RS (Brazil); Rodrigues de Andrade, Heloisa Helena [Laboratorio de Diagnostico da Toxicidade Genetica (TOXIGEN), Programa de Pos Graduacao em Genetica e Toxicologia Aplicada (PPGGTA), Universidade Luterana do Brasil -ULBRA, Avenida Farroupilha 8001, 92420280 Canoas, RS (Brazil)], E-mail: heloisa@ulbra.br

    2008-01-15

    The genotoxicity associated with air pollution in the city of Canoas, Rio Grande do Sul (Brazil), was assessed in November (spring) and January (summer). We applied the somatic mutation and recombination test (SMART) in Drosophila melanogaster in its standard version with normal bioactivation (ST) and in its variant with increased cytochrome P450-dependent biotransformation capacity (HB). The data indicated the genotoxicity of TSP and PM10 collected in November, in both ST and HB crosses. The genotoxic activity of the PM10 material in the spring sample was exclusively associated with the induction of mitotic recombination, whereas the TSP genetic toxicity was due to both recombinational as well as point and/or chromosomal mutation events. Considering PM10 collected in January, a positive response-100% (17.10 m{sup 3}/ml) concentration-was observed in the HB cross, which was not detected in the ST cross. - Drosophila Wing-Spot Test can be used for detection of airborne particulates mutagenesis.

  6. SGA-WZ: A New Strapdown Airborne Gravimeter

    Directory of Open Access Journals (Sweden)

    Kaidong Zhang

    2012-07-01

    Full Text Available Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter taking full advantage of the inertial navigation system is described with improved mechanical design, high precision time synchronization, better thermal control and optimized sensor modeling. Apart from the general usage, the Global Positioning System (GPS after differentiation is integrated to the inertial navigation system which provides not only more precise altitude information along with the navigation aiding, but also an effective way to calculate the vehicle acceleration. Design description and test results on the performance of the gyroscopes and accelerations will be emphasized. Analysis and discussion of the airborne field test results are also given.

  7. Airborne Laser Systems Testing and Analysis (essals et analyse des systemes laser embarques)

    Science.gov (United States)

    2010-04-01

    Pyroelectric Probe PG Proportional Guidance PILASTER PISQ LASer Test and Evaluation Range PIM Pixel Intensity Matrix PISQ Poligono Interforze del Salto di...requirements for upgrading the PISQ test/ training range ( Poligono Interforze del Salto di Quirra – Sardinia – Italy), adding new facilities for...INTRODUCTION This chapter describes the requirements for upgrading the PISQ ( Poligono Interforze del Salto di Quirra – Sardinia, Italy), adding new facilities

  8. Modeling and Testing Dark Energy and Gravity with Galaxy Cluster Data

    Science.gov (United States)

    Rapetti, David; Cataneo, Matteo; Heneka, Caroline; Mantz, Adam; Allen, Steven W.; Von Der Linden, Anja; Schmidt, Fabian; Lombriser, Lucas; Li, Baojiu; Applegate, Douglas; Kelly, Patrick; Morris, Glenn

    2018-06-01

    The abundance of galaxy clusters is a powerful probe to constrain the properties of dark energy and gravity at large scales. We employed a self-consistent analysis that includes survey, observable-mass scaling relations and weak gravitational lensing data to obtain constraints on f(R) gravity, which are an order of magnitude tighter than the best previously achieved, as well as on cold dark energy of negligible sound speed. The latter implies clustering of the dark energy fluid at all scales, allowing us to measure the effects of dark energy perturbations at cluster scales. For this study, we recalibrated the halo mass function using the following non-linear characteristic quantities: the spherical collapse threshold, the virial overdensity and an additional mass contribution for cold dark energy. We also presented a new modeling of the f(R) gravity halo mass function that incorporates novel corrections to capture key non-linear effects of the Chameleon screening mechanism, as found in high resolution N-body simulations. All these results permit us to predict, as I will also exemplify, and eventually obtain the next generation of cluster constraints on such models, and provide us with frameworks that can also be applied to other proposed dark energy and modified gravity models using cluster abundance observations.

  9. Utilization of ISS to Develop and Test Operational Concepts and Hardware for Low-Gravity Terrestrial EVA

    Science.gov (United States)

    Gast, Matthew A.

    2010-01-01

    NASA has considerable experience in two areas of Extravehicular Activities (EVA). The first can be defined as microgravity, orbital EVAs. This consists of everything done in low Earth orbit (LEO), from the early, proof of concept EVAs conducted during the Gemini program of the 1960s, to the complex International Space Station (ISS) assembly tasks of the first decade of the 21st century. The second area of expertise is comprised of those EVAs conducted on the lunar surface, under a gravitational force one-sixth that of Earth. This EVA expertise encapsulates two extremes - microgravity and Earthlike gravitation - but is insufficient as humans expand their exploration purview, most notably with respect to spacewalks conducted on very low-gravity bodies, such as near- Earth objects (NEO) and the moons of Mars. The operational and technical challenges of this category of EVA have yet to be significantly examined, and as such, only a small number of operational concepts have been proposed thus far. To ensure mission success, however, EVA techniques must be developed and vetted to allow the selection of operational concepts that can be utilized across an assortment of destinations whose physical characteristics vary. This paper examines the utilization of ISS-based EVAs to test operational concepts and hardware in preparation for a low-gravity terrestrial EVA. While the ISS cannot mimic some of the fundamental challenges of a low-gravity terrestrial EVA - such as rotation rate and surface composition - it may be the most effective test bed available.

  10. A new airborne Polar Nephelometer for the measurement of optical and microphysical cloud properties. Part II: Preliminary tests

    Directory of Open Access Journals (Sweden)

    O. Crépel

    Full Text Available A new optical sensor, the airborne Polar Nephelometer, has been tested in an open wind tunnel. The wind tunnel was operated in cloudy conditions including either cloud water droplets or ice crystals, or a mixture of these particles. The sensor is designed to measure the optical and microphysical parameters of cloud particles sized from a few micrometers to about 500 µm diameter. Basically, the probe measures the scattering phase function of an ensemble of cloud particles which intersect a collimated laser beam near the focal point of a paraboloidal mirror. From the measured scattering phase function the retrieval of the droplet-size spectra and subsequent derived quantities such as liquid water content and size parameters can be calculated using an inversion method. The particle phase discrimination (water droplets/ice particles can be derived from the shape of the scattering phase function and the sensitivity of the probe allows the detection of small ice crystals (typically of 5 µm diameter. The paper describes the preliminary results obtained by the prototype version of the Polar Nephelometer in various cloudy conditions. These results are compared with direct microphysical measurements obtained by usual PMS probes also mounted in the wind tunnel. Complementary results obtained in a cold chamber are presented in order to illustrate the reliability of the Polar Nephelometer in the presence of small ice crystals.

  11. Disentangling dark energy and cosmic tests of gravity from weak lensing systematics

    Science.gov (United States)

    Laszlo, Istvan; Bean, Rachel; Kirk, Donnacha; Bridle, Sarah

    2012-06-01

    We consider the impact of key astrophysical and measurement systematics on constraints on dark energy and modifications to gravity on cosmic scales. We focus on upcoming photometric ‘stage III’ and ‘stage IV’ large-scale structure surveys such as the Dark Energy Survey (DES), the Subaru Measurement of Images and Redshifts survey, the Euclid survey, the Large Synoptic Survey Telescope (LSST) and Wide Field Infra-Red Space Telescope (WFIRST). We illustrate the different redshift dependencies of gravity modifications compared to intrinsic alignments, the main astrophysical systematic. The way in which systematic uncertainties, such as galaxy bias and intrinsic alignments, are modelled can change dark energy equation-of-state parameter and modified gravity figures of merit by a factor of 4. The inclusion of cross-correlations of cosmic shear and galaxy position measurements helps reduce the loss of constraining power from the lensing shear surveys. When forecasts for Planck cosmic microwave background and stage IV surveys are combined, constraints on the dark energy equation-of-state parameter and modified gravity model are recovered, relative to those from shear data with no systematic uncertainties, provided fewer than 36 free parameters in total are used to describe the galaxy bias and intrinsic alignment models as a function of scale and redshift. While some uncertainty in the intrinsic alignment (IA) model can be tolerated, it is going to be important to be able to parametrize IAs well in order to realize the full potential of upcoming surveys. To facilitate future investigations, we also provide a fitting function for the matter power spectrum arising from the phenomenological modified gravity model we consider.

  12. MSFC Doppler Lidar Science experiments and operations plans for 1981 airborne test flight

    Science.gov (United States)

    Fichtl, G. H.; Bilbro, J. W.; Kaufman, J. W.

    1981-01-01

    The flight experiment and operations plans for the Doppler Lidar System (DLS) are provided. Application of DLS to the study of severe storms and local weather penomena is addressed. Test plans involve 66 hours of flight time. Plans also include ground based severe storm and local weather data acquisition.

  13. Small-sized test of gravity separation and preliminary assessment of technology and economics in Guangshigou granite pegmatite type uranium deposit

    Energy Technology Data Exchange (ETDEWEB)

    Zhifu, Sun; Mingyue, Feng; Jiashu, Rong; Ziyang, Xu [Beijing Research Inst. of Uranium Geology (China)

    1994-11-01

    The small-sized test of gravity separation in Guangshigou granite pegmatite type uranium deposit has found a new avenue for the industrial utilization of ores from such uranium deposit, especially those low grade ones. The test has proved that the gravity separation is superior to hydrometallurgy in the aspect of uranium recovery from ores of the granite pegmatite type uranium deposit, by-product recovery and protection against environmental pollution.

  14. Small-sized test of gravity separation and preliminary assessment of technology and economics in Guangshigou granite pegmatite type uranium deposit

    International Nuclear Information System (INIS)

    Sun Zhifu; Feng Mingyue; Rong Jiashu; Xu Ziyang

    1994-01-01

    The small-sized test of gravity separation in Guangshigou granite pegmatite type uranium deposit has found a new avenue for the industrial utilization of ores from such uranium deposit, especially those low grade ones. The test has proved that the gravity separation is superior to hydrometallurgy in the aspect of uranium recovery from ores of the granite pegmatite type uranium deposit, by-product recovery and protection against environmental pollution

  15. Tonopah Test Range Air Monitoring. CY2014 Meteorological, Radiological, and Airborne Particulate Observations

    Energy Technology Data Exchange (ETDEWEB)

    Nikoloch, George [Desert Research Inst. (DRI), Las Vegas, NV (United States); Shadel, Craig [Desert Research Inst. (DRI), Las Vegas, NV (United States); Chapman, Jenny [Desert Research Inst. (DRI), Las Vegas, NV (United States); Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, Greg [Desert Research Inst. (DRI), Las Vegas, NV (United States); Etyemezian, Vicken [Desert Research Inst. (DRI), Las Vegas, NV (United States); Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2015-10-01

    In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This test resulted in radionuclide-contaminated soils at Clean Slate I, II, and III. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III and at the TTR Range Operations Control center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soils beyond both the physical and administrative boundaries of the sites. Results for the calendar year (CY) 2014 monitoring are: (1) the gross alpha and gross beta values from the monitoring stations are approximately equivalent to the highest values observed during the CY2014 reporting at the surrounding Community Environmental Monitoring Program (CEMP) stations; (2) only naturally occurring radionuclides were identified in the gamma spectral analyses; (3) the ambient gamma radiation measurements indicate that the average annual gamma exposure is similar at all three monitoring stations and periodic intervals of increased gamma values appear to be associated with storm fronts passing through the area; and (4) the concentrations of both resuspended dust and saltated sand particles generally increase with increasing wind speed. Differences in the observed dust concentrations are likely the result of differences in the soil characteristics immediately adjacent to the monitoring stations. Neither the resuspended particulate radiological analyses nor the ambient gamma radiation measurements suggest wind transport of radionuclide-contaminated soils.

  16. Tonopah Test Range Air Monitoring: CY2013 Meteorological, Radiological, and Airborne Particulate Observations

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A [DRI; Nikolich, George [DRI; Shadel, Craig [DRI; McCurdy, Greg [DRI; Etyemezian, Vicken [DRI; Miller, Julianne J [DRI

    2014-10-01

    In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This test resulted in radionuclide-contaminated soils at Clean Slate I, II, and III. This report documents observations made during on-going monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to Clean Slate I and Clean Slate III and at the TTR Range Operations Control center. The primary objective of the monitoring effort is to determine if winds blowing across the Clean Slate sites are transporting particles of radionuclide-contaminated soils beyond both the physical and administrative boundaries of the sites. Results for the calendar year (CY) 2013 monitoring include: (1) the gross alpha and gross beta values from the monitoring stations are approximately equivalent to the highest values observed during the CY2012 reporting at the surrounding Community Environmental Monitoring Program (CEMP) stations (this was the latest documented data available at the time of this writing); (2) only naturally occurring radionuclides were identified in the gamma spectral analyses; (3) the ambient gamma radiation measurements indicate that the average annual gamma exposure is similar at all three monitoring stations and periodic intervals of increased gamma values appear to be associated with storm fronts passing through the area; and (4) the concentrations of both resuspended dust and saltated sand particles generally increase with increasing wind speed. However, differences in the observed dust concentrations are likely due to differences in the soil characteristics immediately adjacent to the monitoring stations. Neither the resuspended particulate radiological analyses nor the ambient gamma radiation measurements suggest wind transport of radionuclide-contaminated soils.

  17. Testing a Novel Method to Approximate Wood Specific Gravity of Trees

    Science.gov (United States)

    Michael C. Wiemann; G. Bruce. Williamson

    2012-01-01

    Wood specific gravity (SG) has long been used by foresters as an index for wood properties. More recently, SG has been widely used by ecologists as a plant functional trait and as a key variable in estimates of biomass. However, sampling wood to determine SG can be problematic; at present, the most common method is sampling with an increment borer to extract a bark-to-...

  18. Testing the inverse-square law of gravity: Error and design with the upward continuation integral

    International Nuclear Information System (INIS)

    Thomas, J.

    1989-01-01

    It has been reported that the inverse-square law of gravity is violated over a range of a few hundred meters. I present a different method for the analysis of the data from that experiment. In this method, the experimental error can be evaluated analytically and I confirm the previous analysis but show that it is a 2σ effect. The method can also be used to design new experiments that will yield minimum errors for a fixed number of data points

  19. Airborne mapping of radioactive contamination. Results from a test in Finland, RESUME95

    Energy Technology Data Exchange (ETDEWEB)

    Roenning, S.; Smethurst, M.A. [Geological Survey of Norway (Norway)

    1997-12-31

    The Geological Survey of Norway participated in the exercise RESUME95 (Rapid Environmental Surveying Using Mobile Equipment 95) in Finland, during August 1995. The purpose of the exercise was to 1) test preparedness in the Nordic countries for accidents involving the release and dispersal of radioactive material, 2) compare results from the different teams participating in the exercise, 3) establish routines for the exchange of data and 4) investigate the possibility of international assistance in the event of nuclear accidents. The Geological Survey of Norway carried out a survey over three test areas (area I, II and III). All three areas were contaminated with man made radionuclides in the days following the Chernobyl nuclear reactor accident. The Cesium-137 contamination level was reported to be about 50 kBq/m{sup 2} in area I, and this area was used for calibration. In area II mapping of Cesium-137 ground concentration was carried out. Detection of hidden artificial radiation sources were the main purpose in area III. This report describes the exercise - RESUME95, field operations, calibration, mapping of Cesium-137 ground concentration and detection of hidden point sources. Results are presented as colour maps. (au).

  20. Airborne mapping of radioactive contamination. Results from a test in Finland, RESUME95

    Energy Technology Data Exchange (ETDEWEB)

    Roenning, S; Smethurst, M A [Geological Survey of Norway (Norway)

    1998-12-31

    The Geological Survey of Norway participated in the exercise RESUME95 (Rapid Environmental Surveying Using Mobile Equipment 95) in Finland, during August 1995. The purpose of the exercise was to 1) test preparedness in the Nordic countries for accidents involving the release and dispersal of radioactive material, 2) compare results from the different teams participating in the exercise, 3) establish routines for the exchange of data and 4) investigate the possibility of international assistance in the event of nuclear accidents. The Geological Survey of Norway carried out a survey over three test areas (area I, II and III). All three areas were contaminated with man made radionuclides in the days following the Chernobyl nuclear reactor accident. The Cesium-137 contamination level was reported to be about 50 kBq/m{sup 2} in area I, and this area was used for calibration. In area II mapping of Cesium-137 ground concentration was carried out. Detection of hidden artificial radiation sources were the main purpose in area III. This report describes the exercise - RESUME95, field operations, calibration, mapping of Cesium-137 ground concentration and detection of hidden point sources. Results are presented as colour maps. (au).

  1. Quantum-gravity-motivated Lorentz-symmetry tests with laser interferometers

    International Nuclear Information System (INIS)

    Amelino-Camelia, Giovanni; Laemmerzahl, Claus

    2004-01-01

    We consider the implications for laser interferometry of the quantum-gravity-motivated modifications in the laws of particle propagation, which are presently being considered in attempts to explain puzzling observations of ultra-high-energy cosmic rays. We show that there are interferometric set-ups in which the Planck-scale effect on propagation leads to a characteristic signature. A naive estimate is encouraging with respect to the possibility of achieving Planck-scale sensitivity, but we also point out some severe technological challenges which would have to be overcome in order to achieve this sensitivity

  2. Airborne gravimetry used in precise geoid computations by ring integration

    DEFF Research Database (Denmark)

    Kearsley, A.H.W.; Forsberg, René; Olesen, Arne Vestergaard

    1998-01-01

    Two detailed geoids have been computed in the region of North Jutland. The first computation used marine data in the offshore areas. For the second computation the marine data set was replaced by the sparser airborne gravity data resulting from the AG-MASCO campaign of September 1996. The results...... of comparisons of the geoid heights at on-shore geometric control showed that the geoid heights computed from the airborne gravity data matched in precision those computed using the marine data, supporting the view that airborne techniques have enormous potential for mapping those unsurveyed areas between...

  3. Development of a new generation gravity map of Antarctica: ADGRAV Antarctic Digital Gravity Synthesis

    Directory of Open Access Journals (Sweden)

    R. A. Arko

    1999-06-01

    Full Text Available The U.S. National Science Foundation (NSF has agreed to support the development of a new generation gravity map of Antarctica (ADGRAV - Antarctic Digital Gravity Synthesis, funding the development of a web based access tool. The goal of this project is the creation of an on-line Antarctic gravity database which will facilitate access to improved high resolution satellite gravity models, in conjunction with shipboard, airborne, and land based gravity measurements for the continental regions. This database will complement parallel projects underway to develop new continental bedrock (BEDMAP and magnetic (ADMAP maps of Antarctica.

  4. Testing a generalized cubic Galileon gravity model with the Coma Cluster

    Energy Technology Data Exchange (ETDEWEB)

    Terukina, Ayumu; Yamamoto, Kazuhiro; Okabe, Nobuhiro [Department of Physical Sciences, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Matsushita, Kyoko; Sasaki, Toru, E-mail: telkina@theo.phys.sci.hiroshima-u.ac.jp, E-mail: kazuhiro@hiroshima-u.ac.jp, E-mail: okabe@hiroshima-u.ac.jp, E-mail: matusita@rs.kagu.tus.ac.jp, E-mail: j1213703@ed.tus.ac.jp [Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

    2015-10-01

    We obtain a constraint on the parameters of a generalized cubic Galileon gravity model exhibiting the Vainshtein mechanism by using multi-wavelength observations of the Coma Cluster. The generalized cubic Galileon model is characterized by three parameters of the turning scale associated with the Vainshtein mechanism, and the amplitude of modifying a gravitational potential and a lensing potential. X-ray and Sunyaev-Zel'dovich (SZ) observations of the intra-cluster medium are sensitive to the gravitational potential, while the weak-lensing (WL) measurement is specified by the lensing potential. A joint fit of a complementary multi-wavelength dataset of X-ray, SZ and WL measurements enables us to simultaneously constrain these three parameters of the generalized cubic Galileon model for the first time. We also find a degeneracy between the cluster mass parameters and the gravitational modification parameters, which is influential in the limit of the weak screening of the fifth force.

  5. Theoretical frameworks for testing relativistic gravity. V - Post-Newtonian limit of Rosen's theory

    Science.gov (United States)

    Lee, D. L.; Ni, W.-T.; Caves, C. M.; Will, C. M.

    1976-01-01

    The post-Newtonian limit of Rosen's theory of gravity is evaluated and is shown to be identical to that of general relativity, except for the post-Newtonian parameter alpha sub 2 (which is related to the difference in propagation speeds for gravitational and electromagnetic waves). Both the value of alpha sub 2 and the value of the Newtonian gravitational constant depend on the present cosmological structure of the Universe. If the cosmological structure has a specific (but presumably special) form, the Newtonian gravitational constant assumes its current value, alpha sub 2 is zero, the post-Newtonian limit of Rosen's theory is identical to that of general relativity - and standard solar system experiments cannot distinguish between the two theories.

  6. Theoretical frameworks for testing relativistic gravity. 5: Post-Newtonian limit of Rosen's theory

    Science.gov (United States)

    Lee, D. L.; Caves, C. M.

    1974-01-01

    The post-Newtonian limit of Rosen's theory of gravity is evaluated and is shown to be identical to that of general relativity, except for the PPN parameter alpha sub 2, which is related to the difference in propagation speeds for gravitational and electromagnetic waves. Both the value of alpha sub 2 and the value of the Newtonian gravitational constant depend on the present cosmological structure of the Universe. If the cosmological structure has a specific but presumably special form, the Newtonian gravitational constant assumes its current value, alpha sub 2 is zero, the post-Newtonian limit of Rosen's theory is identical to that of general relativity--and standard solar system experiments cannot distinguish between the two theories.

  7. A Combined Gravity Compensation Method for INS Using the Simplified Gravity Model and Gravity Database.

    Science.gov (United States)

    Zhou, Xiao; Yang, Gongliu; Wang, Jing; Wen, Zeyang

    2018-05-14

    In recent decades, gravity compensation has become an important way to reduce the position error of an inertial navigation system (INS), especially for a high-precision INS, because of the extensive application of high precision inertial sensors (accelerometers and gyros). This paper first deducts the INS's solution error considering gravity disturbance and simulates the results. Meanwhile, this paper proposes a combined gravity compensation method using a simplified gravity model and gravity database. This new combined method consists of two steps all together. Step 1 subtracts the normal gravity using a simplified gravity model. Step 2 first obtains the gravity disturbance on the trajectory of the carrier with the help of ELM training based on the measured gravity data (provided by Institute of Geodesy and Geophysics; Chinese Academy of sciences), and then compensates it into the error equations of the INS, considering the gravity disturbance, to further improve the navigation accuracy. The effectiveness and feasibility of this new gravity compensation method for the INS are verified through vehicle tests in two different regions; one is in flat terrain with mild gravity variation and the other is in complex terrain with fierce gravity variation. During 2 h vehicle tests, the positioning accuracy of two tests can improve by 20% and 38% respectively, after the gravity is compensated by the proposed method.

  8. Gravity inversion code

    International Nuclear Information System (INIS)

    Burkhard, N.R.

    1979-01-01

    The gravity inversion code applies stabilized linear inverse theory to determine the topography of a subsurface density anomaly from Bouguer gravity data. The gravity inversion program consists of four source codes: SEARCH, TREND, INVERT, and AVERAGE. TREND and INVERT are used iteratively to converge on a solution. SEARCH forms the input gravity data files for Nevada Test Site data. AVERAGE performs a covariance analysis on the solution. This document describes the necessary input files and the proper operation of the code. 2 figures, 2 tables

  9. Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

    Science.gov (United States)

    Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam; hide

    2013-01-01

    Flow boiling and condensation have been identified as two key mechanisms for heat transport that are vital for achieving weight and volume reduction as well as performance enhancement in future space systems. Since inertia driven flows are demanding on power usage, lower flows are desirable. However, in microgravity, lower flows are dominated by forces other than inertia (like the capillary force). It is of paramount interest to investigate limits of low flows beyond which the flow is inertial enough to be gravity independent. One of the objectives of the Flow Boiling and Condensation Flight Experiment sets to investigate these limits for flow boiling and condensation. A two-phase flow loop consisting of a Flow Boiling Module and two Condensation Modules has been developed to experimentally study flow boiling condensation heat transfer in the reduced gravity environment provided by the reduced gravity platform. This effort supports the development of a flow boiling and condensation facility for the International Space Station (ISS). The closed loop test facility is designed to deliver the test fluid, FC-72 to the inlet of any one of the test modules at specified thermodynamic and flow conditions. The zero-g-aircraft tests will provide subcooled and saturated flow boiling critical heat flux and flow condensation heat transfer data over wide range of flow velocities. Additionally, these tests will verify the performance of all gravity sensitive components, such as evaporator, condenser and accumulator associated with the two-phase flow loop. We will present in this paper the breadboard development and testing results which consist of detailed performance evaluation of the heater and condenser combination in reduced and normal gravity. We will also present the design of the reduced gravity aircraft rack and the results of the ground flow boiling heat transfer testing performed with the Flow Boiling Module that is designed to investigate flow boiling heat transfer and

  10. Freqüência de positividade em teste cutâneo para aeroalérgenos Frequency of positive skin tests for airborne allergic agents

    Directory of Open Access Journals (Sweden)

    Ricardo Godinho

    2003-12-01

    frequency of positive skin tests for specific airborne allergic agents, we assessed medical records of 398 patients with nasal symptoms suggestive of allergy or other otolaryngologic complaints which required skin testing to aid in the diagnosis. RESULTS: The most frequently found allergic agents were house dust (74,9%, dermatophagoides farinae (58,4% and mold (36,5%, followed by dog hair (32,7%, grass (22,4%, cat hair (16,9%, feathers (16,4% and wool (15,6%. Only 3,5% were positive for lovebird feathers and 1,5% for flowers. 39 patients (9,8% had negative skin tests, 10 (2,5% had reactions to the solution extract and 8 (2% did not react to histamine. We did not have complications in performing the test. CONCLUSION: House dust was the most frequently found allergic agent. Skin tests must be performed based on the clinical history, and their results may guide us towards the correct diagnosis and treatment of nose diseases.

  11. Gravity wave and neutrino bursts from stellar collapse: A sensitive test of neutrino masses

    International Nuclear Information System (INIS)

    Arnaud, N.; Barsuglia, M.; Bizouard, M.A.; Cavalier, F.; Davier, M.; Hello, P.; Pradier, T.

    2002-01-01

    New methods are proposed with the goal to determine absolute neutrino masses from the simultaneous observation of the bursts of neutrinos and gravitational waves emitted during a stellar collapse. It is shown that the neutronization electron neutrino flash and the maximum amplitude of the gravitational wave signal are tightly synchronized with the bounce occurring at the end of the core collapse on a time scale better than 1 ms. The existing underground neutrino detectors (SuperKamiokande, SNO,...) and the gravity wave antennas soon to operate (LIGO, VIRGO,...) are well matched in their performance for detecting galactic supernovae and for making use of the proposed approach. Several methods are described, which apply to the different scenarios depending on neutrino mixing. Given the present knowledge on neutrino oscillations, the methods proposed are sensitive to a mass range where neutrinos would essentially be mass degenerate. The 95% C.L. upper limit which can be achieved varies from 0.75 eV/c 2 for large ν e survival probabilities to 1.1 eV/c 2 when in practice all ν e 's convert into ν μ 's or ν τ 's. The sensitivity is nearly independent of the supernova distance

  12. Testing feasibility of scalar-tensor gravity by scale dependent mass and coupling to matter

    International Nuclear Information System (INIS)

    Mota, D. F.; Salzano, V.; Capozziello, S.

    2011-01-01

    We investigate whether there is any cosmological evidence for a scalar field with a mass and coupling to matter which change accordingly to the properties of the astrophysical system it ''lives in,'' without directly focusing on the underlying mechanism that drives the scalar field scale-dependent-properties. We assume a Yukawa type of coupling between the field and matter and also that the scalar-field mass grows with density, in order to overcome all gravity constraints within the Solar System. We analyze three different gravitational systems assumed as ''cosmological indicators'': supernovae type Ia, low surface brightness spiral galaxies and clusters of galaxies. Results show (i) a quite good fit to the rotation curves of low surface brightness galaxies only using visible stellar and gas-mass components is obtained; (ii) a scalar field can fairly well reproduce the matter profile in clusters of galaxies, estimated by x-ray observations and without the need of any additional dark matter; and (iii) there is an intrinsic difficulty in extracting information about the possibility of a scale-dependent massive scalar field (or more generally about a varying gravitational constant) from supernovae type Ia.

  13. Airborne Video Surveillance

    National Research Council Canada - National Science Library

    Blask, Steven

    2002-01-01

    The DARPA Airborne Video Surveillance (AVS) program was established to develop and promote technologies to make airborne video more useful, providing capabilities that achieve a UAV force multiplier...

  14. Status of the planar electrostatic gradiometer GREMLIT for airborne geodesy

    Science.gov (United States)

    Lebat, V.; Foulon, B.; Christophe, B.; Huynh, P. A.; Liorzou, F.; Boulanger, D.

    2017-12-01

    Taking advantage of technologies, developed by ONERA for the GRACE, GOCE and GRACE FOLLOW-ON space missions, the GREMLIT airborne gravity gradiometer is based of a planar electrostatic gradiometer configuration. The feasibility of the instrument and of its performance was proved by realistic simulations, based on actual data and recorded environmental aircraft perturbations, with performance of about one Eötvös along the two horizontal components of the gravity gradient. The performance of the gradiometer is directly linked to the stabilized platform, controlled by the common mode outputs of the instrument itself, in order to reject the perturbations induced by the airborne environment in the horizontal directions. After the definition of the architecture of the stabilized platform to achieve the global performance of the gradiometer, the platform has been manufactured and integrated. In order to assess the operation of the electrostatic gradiometer on its associated stabilized platform, a one axis prototype has also been built. The poster will emphasize the status of realization and first tests of the instrument and of its stabilized platform.

  15. TRACG prediction of gravity-driven cooling system response in the SBWR/GIST facility LOCA tests

    International Nuclear Information System (INIS)

    Alamgir, M.; Andersen, J.G.M.; Yang, A.I.; Shiralkar, B.S.

    1990-01-01

    General Electric (BE) Nuclear Energy has initiated work on technology programs in support of the advanced light water reactor (ALWR) plants under contract to the U.S. Department of Energy (DOE). Work has been performed under the advanced boiling water reactor (ABWT) design verification program and the simplified boiling water reactor (SBWR) program. The objective of the SBWR program is to develop the key features of a simplified reactor design. The gravity-driven cooling system (GDCS) is an important feature of the SBWR design. The main objectives of the GDCS test program at GE were to demonstrate the technical feasibility of the GDCS concept by performing a section-scaled integrated systems test of the SBWR design and to provide a data base to qualify the TRACG computer code for use in SBWR accident analysis. This paper describes the qualification of TRACG for GDCS applications. The calculational capability and analytical models of TRACG are tested by performing assessment analysis for five loss-of-coolant-accident (LOCA) tests in the GDCS Integrated Systems Test (GIST) facility. The results of the qualification comparisons are presented and TRACG application ranges are discussed

  16. Massive Gravity

    OpenAIRE

    de Rham, Claudia

    2014-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware–Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...

  17. Evaluation of the Thermophysical Properties of Poly(MethylMethacrylate): A Reference Material for the Development of a flammability Test for Micro-Gravity Environments

    OpenAIRE

    Steinhaus, Thomas

    1999-01-01

    A study has been conducted using PMMA (Poly(methyl methacrylate)) as a reference material in the development process of the Forced Flow and flame Spread Test (FIST). This test attempts to establish different criteria for material flammability for micro-gravity environments. The FIST consists of two tests, ignition and flame spread tests, that provide a series of material “fire” properties that jointly provide important information on the flammability of a material. This work de...

  18. Diagnostic accuracy of the gravity stress test and clinical signs in cases of isolated supination-external rotation-type lateral malleolar fractures.

    Science.gov (United States)

    Nortunen, S; Flinkkilä, T; Lantto, I; Kortekangas, T; Niinimäki, J; Ohtonen, P; Pakarinen, H

    2015-08-01

    We prospectively assessed the diagnostic accuracy of the gravity stress test and clinical findings to evaluate the stability of the ankle mortise in patients with supination-external rotation-type fractures of the lateral malleolus without widening of the medial clear space. The cohort included 79 patients with a mean age of 44 years (16 to 82). Two surgeons assessed medial tenderness, swelling and ecchymosis and performed the external rotation (ER) stress test (a reference standard). A diagnostic radiographer performed the gravity stress test. For the gravity stress test, the positive likelihood ratio (LR) was 5.80 with a 95% confidence interval (CI) of 2.75 to 12.27, and the negative LR was 0.15 (95% CI 0.07 to 0.35), suggesting a moderate change from the pre-test probability. Medial tenderness, both alone and in combination with swelling and/or ecchymosis, indicated a small change (positive LR, 2.74 to 3.25; negative LR, 0.38 to 0.47), whereas swelling and ecchymosis indicated only minimal changes (positive LR, 1.41 to 1.65; negative LR, 0.38 to 0.47). In conclusion, when gravity stress test results are in agreement with clinical findings, the result is likely to predict stability of the ankle mortise with an accuracy equivalent to ER stress test results. When clinical examination suggests a medial-side injury, however, the gravity stress test may give a false negative result. ©2015 The British Editorial Society of Bone & Joint Surgery.

  19. Airborne gravimetry for geoid and GOCE

    DEFF Research Database (Denmark)

    Forsberg, R.; Olesen, A. V.; Nielsen, E.

    2014-01-01

    DTU-Space has since 1996 carried out large area airborne surveys over both polar, tropical and temperate regions, especially for geoid determination and global geopotential models. Recently we have started flying two gravimeters (LCR and Chekan-AM) side by side for increased reliability and redun......DTU-Space has since 1996 carried out large area airborne surveys over both polar, tropical and temperate regions, especially for geoid determination and global geopotential models. Recently we have started flying two gravimeters (LCR and Chekan-AM) side by side for increased reliability...... in Antarctica and Tanzania based on DTU-Space aerogravity and GOCE. In both cases the airborne data validate GOCE to very high degrees, and confirms the synergy of airborne gravity and GOCE. For Antarctica, the deep interior Antarctic survey (continued in 2013 from a remote field camp), shows...... that it is possible efficiently to cover even the most remote regions on the planet with good aerogravity. With the recent termination of the GOCE mission, it is therefore timely to initiate a coordinated, preferably international, airborne gravity effort to cover the polar gap south of 83° S; such a survey can...

  20. CLASH-VLT: testing the nature of gravity with galaxy cluster mass profiles

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuti, L.; Sartoris, B.; Borgani, S.; Girardi, M. [Dipartimento di Fisica, Sezione di Astronomia, Università di Trieste, Via Tiepolo 11, I-34143 Trieste (Italy); Amendola, L. [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany); Umetsu, K. [5 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Biviano, A.; Balestra, I.; Nonino, M. [INAF—Osservatorio Astronomico di Trieste, Via Tiepolo 11, I-34143 Trieste (Italy); Rosati, P. [University Observatory Munich, Scheinerstrasse 1, D-81679 Mu\\' nchen (Germany); Caminha, G.B. [Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via Saragat 1, I-44122 Ferrara (Italy); Frye, B. [Steward Observatory/Department of Astronomy, University of Arizona, 933 N Cherry Ave, Tucson, AZ 85721 (United States); Koekemoer, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Grillo, C. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Lombardi, M. [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, I-20133 Milan (Italy); Mercurio, A., E-mail: pizzuti@oats.inaf.it, E-mail: barbara.sartoris@gmail.com, E-mail: borgani@oats.inaf.it, E-mail: l.amendola@thphys.uniheidelberg.de [Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-80131 Napoli (Italy)

    2016-04-01

    We use high-precision kinematic and lensing measurements of the total mass profile of the dynamically relaxed galaxy cluster MACS J1206.2-0847 at z=0.44 to estimate the value of the ratio η=Ψ/Φ between the two scalar potentials in the linear perturbed Friedmann-Lemaitre-Robertson-Walker metric. An accurate measurement of this ratio, called anisotropic stress, could show possible, interesting deviations from the predictions of the theory of General Relativity, according to which Ψ should be equal to Φ. Complementary kinematic and lensing mass profiles were derived from exhaustive analyses using the data from the Cluster Lensing And Supernova survey with Hubble (CLASH) and the spectroscopic follow-up with the Very Large Telescope (CLASH-VLT). Whereas the kinematic mass profile tracks only the time-time part of the perturbed metric (i.e. only Φ), the lensing mass profile reflects the contribution of both time-time and space-space components (i.e. the sum Φ+Ψ). We thus express η as a function of the mass profiles and perform our analysis over the radial range 0.5 Mpc≤ r≤ r{sub 200}=1.96 Mpc. Using a spherical Navarro-Frenk-White mass profile, which well fits the data, we obtain η(r{sub 200})=1.01 {sub −0.28}{sup +0.31} at the 68% C.L. We discuss the effect of assuming different functional forms for mass profiles and of the orbit anisotropy in the kinematic reconstruction. Interpreting this result within the well-studied f(R) modified gravity model, the constraint on η translates into an upper bound to the interaction length (inverse of the scalaron mass) smaller than 2 Mpc. This tight constraint on the f(R) interaction range is however substantially relaxed when systematic uncertainties in the analysis are considered. Our analysis highlights the potential of this method to detect deviations from general relativity, while calling for the need of further high-quality data on the total mass distribution of clusters and improved control on systematic

  1. Z-2 Suit Support Stand and MKIII Suit Center of Gravity Test

    Science.gov (United States)

    Nguyen, Tuan Q.

    2014-01-01

    NASA's next generation spacesuits are the Z-Series suits, made for a range of possible exploration missions in the near future. The prototype Z-1 suit has been developed and assembled to incorporate new technologies that has never been utilized before in the Apollo suits and the Extravehicular Mobility Unit (EMU). NASA engineers tested the Z-1 suit extensively in order to developed design requirements for the new Z-2 suit. At the end of 2014, NASA will be receiving the new Z-2 suit to perform more testing and to further develop the new technologies of the suit. In order to do so, a suit support stand will be designed and fabricated to support the Z-2 suit during maintenance, sizing, and structural leakage testing. The Z-2 Suit Support Stand (Z2SSS) will be utilized for these purposes in the early testing stages of the Z-2 suit.

  2. Airborne testing and demonstration of a new flight system based on an Aerodyne N2O-CO2-CO-H2O mini-spectrometer

    Science.gov (United States)

    Gvakharia, A.; Kort, E. A.; Smith, M. L.; Conley, S.

    2017-12-01

    Nitrous oxide (N2O) is a powerful greenhouse gas and ozone depleting substance. With high atmospheric backgrounds and small relative signals, N2O emissions have been challenging to observe and understand on regional scales with traditional instrumentation. Fast-response airborne measurements with high precision and accuracy can potentially bridge this observational gap. Here we present flight assessments of a new flight system based on an Aerodyne mini-spectrometer as well as a Los Gatos N2O/CO analyzer during the Fertilizer Emissions Airborne Study (FEAST). With the Scientific Aviation Mooney aircraft, we conducted test flights for both analyzers where a known calibration gas was sampled throughout the flight (`null' tests). Clear altitude/cabin-pressure dependencies were observed for both analyzers if operated in an "off-the-shelf' manner. For the remainder of test flights and the FEAST campaign we used a new flight system based on an Aerodyne mini-spectrometer with the addition of a custom pressure control/calibration system. Instead of using traditional approaches with spectral-zeros and infrequent in-flight calibrations, we employ a high-flow system with stable flow control to enable high frequency (2 minutes), short duration (15 seconds) sampling of a known calibration gas. This approach, supported by the null test, enables correction for spectral drift caused by a variety of factors while maintaining a 90% duty cycle for 1Hz sampling from an aircraft. Preliminary in-flight precisions are estimated at 0.05 ppb, 0.1 ppm, 1 ppb, and 10 ppm for N2O, CO2, CO, and H2O respectively. We also present a further 40 hours of inter-comparison in flight with a Picarro 2301-f ring-down spectrometer demonstrating consistency between CO2 and H2O measurements and no altitude dependent error.

  3. RELAP4/MOD6 analysis of forced- and gravity-feed reflood tests

    International Nuclear Information System (INIS)

    Chen, T.H.; Fletcher, C.D.

    1980-01-01

    The RELAP4/MOD6 computer code is used for the analysis of the reactor core heat transfer during the reflooding phase of a postulated loss-of-coolant accident (LOCA) in a pressurized water reactor (PWR). The code requires the user to specify input parameters for the reflood heat transfer models. Results of previous comparisons of code calculations with experimental data have indicated no single selection of input parameters is adequate for a spectrum of tests and test facilities. This paper presents the development of revised quidelines and assesses the effect of those modifications on RELAP4/MOD6 data comparisons using previously analyzed reflood experiments. The paper also presents an assessment of the revised guidelines and the original guidelines against experimental data significantly different from previously analyzed tests

  4. Study on Viscoelastic Deformation Monitoring Index of an RCC Gravity Dam in an Alpine Region Using Orthogonal Test Design

    Directory of Open Access Journals (Sweden)

    Yaoying Huang

    2018-01-01

    Full Text Available The main objective of this study is to present a method of determining viscoelastic deformation monitoring index of a Roller-compacted concrete (RCC gravity dam in an alpine region. By focusing on a modified deformation monitoring model considering frost heave and back analyzed mechanical parameters of the dam, the working state of viscoelasticity for the dam is illustrated followed by an investigation and designation of adverse load cases using orthogonal test method. Water pressure component is then calculated by finite element method, while temperature, time effect, and frost heave components are obtained through deformation statistical model considering frost heave. The viscoelastic deformation monitoring index is eventually determined by small probability and maximum entropy methods. The results show that (a with the abnormal probability 1% the dam deformation monitoring index for small probability and maximum entropy methods is 23.703 mm and 22.981 mm, respectively; thus the maximum measured displacement of the dam is less than deformation monitoring index, which indicates that the dam is currently in a state of safety operation and (b the obtained deformation monitoring index using orthogonal test method is more accurate due to the full consideration of more random factors; the method gained from this study will likely be of use to diagnose the working state for those RCC dams in alpine regions.

  5. Are we close to putting the anomalous perihelion precessions from Verlinde's emergent gravity to the test?

    Energy Technology Data Exchange (ETDEWEB)

    Iorio, Lorenzo [Ministero dell' Istruzione, Universita e della Ricerca (M.I.U.R.)-Istruzione, Bari, BA (Italy)

    2017-03-15

    In the framework of the emergent gravity scenario by Verlinde, it was recently observed by Liu and Prokopec that, among other things, an anomalous pericenter precession would affect the orbital motion of a test particle orbiting an isolated central body. Here, it is shown that, if it were real, its expected magnitude for the inner planets of the Solar System would be at the same level of the present-day accuracy in constraining any possible deviations from their standard perihelion precessions as inferred from long data records spanning about the last century. The most favorable situation for testing the Verlinde-type precession seems to occur for Mars. Indeed, according to recent versions of the EPM and INPOP planetary ephemerides, non-standard perihelion precessions, of whatsoever physical origin, which are larger than some ∼ 0.02-0.11 milliarcseconds per century are not admissible, while the putative precession predicted by Liu and Prokopec amounts to 0.09 milliarcseconds per century. Other potentially interesting astronomical and astrophysical scenarios like, e.g., the Earth's LAGEOS II artificial satellite, the double pulsar system PSR J0737-3039A/B and the S-stars orbiting the Supermassive Black Hole in Sgr A* are, instead, not viable because of the excessive smallness of the predicted precessions for them. (orig.)

  6. Mobile work station concept for assembly of large space structures (zero gravity simulation tests)

    Science.gov (United States)

    Heard, W. L., Jr.; Bush, H. G.; Wallsom, R. E.; Jensen, J. K.

    1982-03-01

    The concept presented is intended to enhance astronaut assembly of truss structure that is either too large or complex to fold for efficient Shuttle delivery to orbit. The potential of augmented astronaut assembly is illustrated by applying the result of the tests to a barebones assembly of a truss structure. If this structure were assembled from the same nestable struts that were used in the Mobile Work Station assembly tests, the spacecraft would be 55 meters in diameter and consist of about 500 struts. The struts could be packaged in less than 1/2% of the Shuttle cargo bay volume and would take up approximately 3% of the mass lift capability. They could be assembled in approximately four hours. This assembly concept for erectable structures is not only feasible, but could be used to significant economic advantage by permitting the superior packaging feature of erectable structures to be exploited and thereby reduce expensive Shuttle delivery flights.

  7. Miniaturised Gravity Sensors for Remote Gravity Surveys.

    Science.gov (United States)

    Middlemiss, R. P.; Bramsiepe, S. G.; Hough, J.; Paul, D. J.; Rowan, S.; Samarelli, A.; Hammond, G.

    2016-12-01

    Gravimetry lets us see the world from a completely different perspective. The ability to measure tiny variations in gravitational acceleration (g), allows one to see not just the Earth's gravitational pull, but the influence of smaller objects. The more accurate the gravimeter, the smaller the objects one can see. Gravimetry has applications in many different fields: from tracking magma moving under volcanoes before eruptions; to locating hidden tunnels. The top commercial gravimeters weigh tens of kg and cost at least $100,000, limiting the situations in which they can be used. By contrast, smart phones use a MEMS (microelectromechanical system) accelerometer that can measure the orientation of the device. These are not nearly sensitive or stable enough to be used for the gravimetry but they are cheap, light-weight and mass-producible. At Glasgow University we have developed a MEMS device with both the stability and sensitivity for useful gravimetric measurements. This was demonstrated by a measurement of the Earth tides - the first time this has been achieved with a MEMS sensor. A gravimeter of this size opens up the possiblility for new gravity imaging modalities. Thousands of gravimeters could be networked over a survey site, storing data on an SD card or communicating wirelessly to a remote location. These devices could also be small enough to be carried by a UAVs: airborne gravity surveys could be carried out at low altitude by mulitple UAVs, or UAVs could be used to deliver ground based gravimeters to remote or inaccessible locations.

  8. Laboratory testing of rock and salt samples for determination of specific gravity and total porosity of the Zeeck No. 1 well (PD-7), Palo Duro Basin, Texas: unanalyzed data

    International Nuclear Information System (INIS)

    1984-07-01

    This report contains the specific gravity and total porosity determinations for rock and salt samples from Zeeck No. 1 Well of the Permian Basin. The laboratory test samples were measured for water content, apparent specific gravity, specific gravity of solids, total porosity and effective porosity. Specimen descriptions including specimen number, formation/group, and lithologic description as well as typical data sheets are included in the appendices. These data are preliminary. They have been neither analyzed nor evaluated

  9. The Future of Gravity

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Of the four fundamental forces, gravity has been studied the longest, yet gravitational physics is one of the most rapidly developing areas of science today. This talk will give a broad brush survey of the past achievements and future prospects of general relativistic gravitational physics. Gravity is a two frontier science being important on both the very largest and smallest length scales considered in contemporary physics. Recent advances and future prospects will be surveyed in precision tests of general relativity, gravitational waves, black holes, cosmology and quantum gravity. The aim will be an overview of a subject that is becoming increasingly integrated with experiment and other branches of physics.

  10. Constraints on LISA Pathfinder's Self-Gravity: Design Requirements, Estimates and Testing Procedures

    Science.gov (United States)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, M.; Brandt, Nico; Bursi, Alessandro; Slutsky. J.; hide

    2016-01-01

    LISA Pathfinder satellite was launched on 3 December 2015 toward the Sun Earth first Lagrangian point (L1) where the LISA Technology Package (LTP), which is the main science payload, will be tested. LTP achieves measurements of differential acceleration of free-falling test masses (TMs) with sensitivity below 3 x 10(exp -14) m s(exp -2) Hz(exp - 1/2) within the 130 mHz frequency band in one dimension. The spacecraft itself is responsible for the dominant differential gravitational field acting on the two TMs. Such a force interaction could contribute a significant amount of noise and thus threaten the achievement of the targeted free-fall level. We prevented this by balancing the gravitational forces to the sub nm s(exp -2) level, guided by a protocol based on measurements of the position and the mass of all parts that constitute the satellite, via finite element calculation tool estimates. In this paper, we will introduce the gravitational balance requirements and design, and then discuss our predictions for the balance that will be achieved in flight.

  11. Gravity gradiometer system for Earth Exploration

    NARCIS (Netherlands)

    Cuperus, R.; Flokstra, F.F.; Droogendijk, H.; Wiegerink, Remco J.; Flokstra, Jakob; Flokstra, Jan

    2009-01-01

    We develop a gravity gradiometer (GG) for use on planetary missions to planets like Mars and Jupiter. With some modifications this development is extended to include (airborne) applications for the Dutch exploratory industry. We adapt key technology of the space based GG for the use in an

  12. The effects of gravity on human walking: a new test of the dynamic similarity hypothesis using a predictive model.

    Science.gov (United States)

    Raichlen, David A

    2008-09-01

    The dynamic similarity hypothesis (DSH) suggests that differences in animal locomotor biomechanics are due mostly to differences in size. According to the DSH, when the ratios of inertial to gravitational forces are equal between two animals that differ in size [e.g. at equal Froude numbers, where Froude = velocity2/(gravity x hip height)], their movements can be made similar by multiplying all time durations by one constant, all forces by a second constant and all linear distances by a third constant. The DSH has been generally supported by numerous comparative studies showing that as inertial forces differ (i.e. differences in the centripetal force acting on the animal due to variation in hip heights), animals walk with dynamic similarity. However, humans walking in simulated reduced gravity do not walk with dynamically similar kinematics. The simulated gravity experiments did not completely account for the effects of gravity on all body segments, and the importance of gravity in the DSH requires further examination. This study uses a kinematic model to predict the effects of gravity on human locomotion, taking into account both the effects of gravitational forces on the upper body and on the limbs. Results show that dynamic similarity is maintained in altered gravitational environments. Thus, the DSH does account for differences in the inertial forces governing locomotion (e.g. differences in hip height) as well as differences in the gravitational forces governing locomotion.

  13. Testing the Equivalence Principle in an Einstein Elevator: Detector Dynamics and Gravity Perturbations

    Science.gov (United States)

    Hubbard, Dorthy (Technical Monitor); Lorenzini, E. C.; Shapiro, I. I.; Cosmo, M. L.; Ashenberg, J.; Parzianello, G.; Iafolla, V.; Nozzoli, S.

    2003-01-01

    We discuss specific, recent advances in the analysis of an experiment to test the Equivalence Principle (EP) in free fall. A differential accelerometer detector with two proof masses of different materials free falls inside an evacuated capsule previously released from a stratospheric balloon. The detector spins slowly about its horizontal axis during the fall. An EP violation signal (if present) will manifest itself at the rotational frequency of the detector. The detector operates in a quiet environment as it slowly moves with respect to the co-moving capsule. There are, however, gravitational and dynamical noise contributions that need to be evaluated in order to define key requirements for this experiment. Specifically, higher-order mass moments of the capsule contribute errors to the differential acceleration output with components at the spin frequency which need to be minimized. The dynamics of the free falling detector (in its present design) has been simulated in order to estimate the tolerable errors at release which, in turn, define the release mechanism requirements. Moreover, the study of the higher-order mass moments for a worst-case position of the detector package relative to the cryostat has led to the definition of requirements on the shape and size of the proof masses.

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

    International Nuclear Information System (INIS)

    Lopez, Alejandro; Freese, Katherine

    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 7  GeV∼< ε 1/4  ∼< 10 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

  15. Minimally modified theories of gravity: a playground for testing the uniqueness of general relativity

    Science.gov (United States)

    Carballo-Rubio, Ra{úl; Di Filippo, Francesco; Liberati, Stefano

    2018-06-01

    In a recent paper [1], it was introduced a new class of gravitational theories with two local degrees of freedom. The existence of these theories apparently challenges the distinctive role of general relativity as the unique non-linear theory of massless spin-2 particles. Here we perform a comprehensive analysis of these theories with the aim of (i) understanding whether or not these are actually equivalent to general relativity, and (ii) finding the root of the variance in case these are not. We have found that a broad set of seemingly different theories actually pass all the possible tests of equivalence to general relativity (in vacuum) that we were able to devise, including the analysis of scattering amplitudes using on-shell techniques. These results are complemented with the observation that the only examples which are manifestly not equivalent to general relativity either do not contain gravitons in their spectrum, or are not guaranteed to include only two local degrees of freedom once radiative corrections are taken into account. Coupling to matter is also considered: we show that coupling these theories to matter in a consistent way is not as straightforward as one could expect. Minimal coupling, as well as the most straightforward non-minimal couplings, cannot be used. Therefore, before being able to address any issues in the presence of matter, it would be necessary to find a consistent (and in any case rather peculiar) coupling scheme.

  16. Advances and Best Practices in Airborne Gravimetry from the U.S. GRAV-D Project

    Science.gov (United States)

    Diehl, Theresa; Childers, Vicki; Preaux, Sandra; Holmes, Simon; Weil, Carly

    2013-04-01

    The Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project, an official policy of the U.S. National Geodetic Survey as of 2007, is working to survey the entire U.S. and its holdings with high-altitude airborne gravimetry. The goal of the project is to provide a consistent, high-quality gravity dataset that will become the cornerstone of a new gravimetric geoid and national vertical datum in 2022. Over the last five years, the GRAV-D project has surveyed more than 25% of the country, accomplishing almost 500 flights on six different aircraft platforms and producing more than 3.7 Million square km of data thus far. This wealth of experience has led to advances in the collection, processing, and evaluation of high-altitude (20,000 - 35,000 ft) airborne gravity data. This presentation will highlight the most important practical and theoretical advances of the GRAV-D project, giving an introduction to each. Examples of innovation include: 1. Use of navigation grade inertial measurement unit data and precise lever arm measurements for positioning; 2. New quality control tests and software for near real-time analysis of data in the field; 3. Increased accuracy of gravity post-processing by reexamining assumptions and simplifications that were inconsistent with a goal of 1 mGal precision; and 4. Better final data evaluation through crossovers, additional statistics, and inclusion of airborne data into harmonic models that use EGM08 as a base model. The increases in data quality that resulted from implementation of the above advances (and others) will be shown with a case study of the GRAV-D 2008 southern Alaska survey near Anchorage, over Cook Inlet. The case study's statistics and comparisons to global models illustrate the impact that these advances have had on the final airborne gravity data quality. Finally, the presentation will summarize the best practices identified by the project from its last five years of experience.

  17. Testing Einstein's gravity and dark energy with growth of matter perturbations: Indications for new physics?

    Science.gov (United States)

    Basilakos, Spyros; Nesseris, Savvas

    2016-12-01

    The growth index of matter fluctuations is computed for ten distinct accelerating cosmological models and confronted by the latest growth-rate data via a two-step process. First, we implement a joint statistical analysis in order to place constraints on the free parameters of all models using solely background data. Second, using the observed growth rate of clustering from various galaxy surveys we test the performance of the current cosmological models at the perturbation level while either marginalizing over σ8 or having it as a free parameter. As a result, we find that at a statistical level, i.e., after considering the best-fit χ2 or the value of the Akaike information criterion, most models are in very good agreement with the growth-rate data and are practically indistinguishable from Λ CDM . However, when we also consider the internal consistency of the models by comparing the theoretically predicted values of (γ0,γ1), i.e., the value of the growth index γ (z ) and its derivative today, with the best-fit ones, we find that the predictions of three out of ten dark energy models are in mild tension with the best-fit ones when σ8 is marginalized over. When σ8 is free we find that most models are not only in mild tension, but also predict low values for σ8. This could be attributed to either a systematic problem with the growth-rate data or the emergence of new physics at low redshifts, with the latter possibly being related to the well-known issue of the lack of power at small scales. Finally, by utilizing mock data based on an large synoptic survey telescope-like survey we show that with future surveys and by using the growth index parametrization, it will be possible to resolve the issue of the low σ8 but also the tension between the fitted and theoretically predicted values of (γ0,γ1).

  18. Nonlocal gravity

    CERN Document Server

    Mashhoon, Bahram

    2017-01-01

    Relativity theory is based on a postulate of locality, which means that the past history of the observer is not directly taken into account. This book argues that the past history should be taken into account. In this way, nonlocality---in the sense of history dependence---is introduced into relativity theory. The deep connection between inertia and gravitation suggests that gravity could be nonlocal, and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein's theory of gravitation has recently been developed. A significant consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. According to nonlocal gravity theory, what astronomers attribute to dark matter should instead be due to the nonlocality of gravitation. Nonlocality dominates on the scale of galaxies and beyond. Memory fades with time; therefore, the nonlocal aspect of gravity becomes wea...

  19. Optical Airborne Tracker System

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Airborne Tracker System (OATS) is an airborne dual-axis optical tracking system capable of pointing at any sky location or ground target.  The objectives...

  20. Massive gravity from bimetric gravity

    International Nuclear Information System (INIS)

    Baccetti, Valentina; Martín-Moruno, Prado; Visser, Matt

    2013-01-01

    We discuss the subtle relationship between massive gravity and bimetric gravity, focusing particularly on the manner in which massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure is more delicate than currently appreciated. Specifically, this limiting procedure should not unnecessarily constrain the background metric, which must be externally specified by the theory of massive gravity itself. The fact that in bimetric theories one always has two sets of metric equations of motion continues to have an effect even in the massive gravity limit, leading to additional constraints besides the one set of equations of motion naively expected. Thus, since solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true, there is no complete continuity in the parameter space of the theory. In particular, we study the massive cosmological solutions which are continuous in the parameter space, showing that many interesting cosmologies belong to this class. (paper)

  1. Gravity brake

    Science.gov (United States)

    Lujan, Richard E.

    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.

  2. Analogue Gravity

    Directory of Open Access Journals (Sweden)

    Barceló Carlos

    2005-12-01

    Full Text Available Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.

  3. Quantum Gravity

    OpenAIRE

    Alvarez, Enrique

    2004-01-01

    Gravitons should have momentum just as photons do; and since graviton momentum would cause compression rather than elongation of spacetime outside of matter; it does not appear that gravitons are compatible with Swartzchild's spacetime curvature. Also, since energy is proportional to mass, and mass is proportional to gravity; the energy of matter is proportional to gravity. The energy of matter could thus contract space within matter; and because of the inter-connectedness of space, cause the...

  4. A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model. Measurement of Earth's dragging of inertial frames

    Energy Technology Data Exchange (ETDEWEB)

    Ciufolini, Ignazio [Universita del Salento, Dipartimento Ingegneria dell' Innovazione, Lecce (Italy); Sapienza Universita di Roma, Scuola di Ingegneria Aerospaziale, Rome (Italy); Paolozzi, Antonio; Paris, Claudio [Sapienza Universita di Roma, Scuola di Ingegneria Aerospaziale, Rome (Italy); Museo della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome (Italy); Pavlis, Erricos C. [University of Maryland, Joint Center for Earth Systems Technology (JCET), Baltimore County (United States); Koenig, Rolf [GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam (Germany); Ries, John [University of Texas at Austin, Center for Space Research, Austin (United States); Gurzadyan, Vahe; Khachatryan, Harutyun; Mirzoyan, Sergey [Alikhanian National Laboratory and Yerevan State University, Center for Cosmology and Astrophysics, Yerevan (Armenia); Matzner, Richard [University of Texas at Austin, Theory Center, Austin (United States); Penrose, Roger [University of Oxford, Mathematical Institute, Oxford (United Kingdom); Sindoni, Giampiero [Sapienza Universita di Roma, DIAEE, Rome (Italy)

    2016-03-15

    We present a test of general relativity, the measurement of the Earth's dragging of inertial frames. Our result is obtained using about 3.5 years of laser-ranged observations of the LARES, LAGEOS, and LAGEOS 2 laser-ranged satellites together with the Earth gravity field model GGM05S produced by the space geodesy mission GRACE. We measure μ = (0.994 ± 0.002) ± 0.05, where μ is the Earth's dragging of inertial frames normalized to its general relativity value, 0.002 is the 1-sigma formal error and 0.05 is our preliminary estimate of systematic error mainly due to the uncertainties in the Earth gravity model GGM05S. Our result is in agreement with the prediction of general relativity. (orig.)

  5. A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model: Measurement of Earth's dragging of inertial frames.

    Science.gov (United States)

    Ciufolini, Ignazio; Paolozzi, Antonio; Pavlis, Erricos C; Koenig, Rolf; Ries, John; Gurzadyan, Vahe; Matzner, Richard; Penrose, Roger; Sindoni, Giampiero; Paris, Claudio; Khachatryan, Harutyun; Mirzoyan, Sergey

    2016-01-01

    We present a test of general relativity, the measurement of the Earth's dragging of inertial frames. Our result is obtained using about 3.5 years of laser-ranged observations of the LARES, LAGEOS, and LAGEOS 2 laser-ranged satellites together with the Earth gravity field model GGM05S produced by the space geodesy mission GRACE. We measure [Formula: see text], where [Formula: see text] is the Earth's dragging of inertial frames normalized to its general relativity value, 0.002 is the 1-sigma formal error and 0.05 is our preliminary estimate of systematic error mainly due to the uncertainties in the Earth gravity model GGM05S. Our result is in agreement with the prediction of general relativity.

  6. Steps towards a quantum theory of gravity

    International Nuclear Information System (INIS)

    Unruh, W.G.

    1984-01-01

    The paper concerns simple experiments in quantum gravity. 'Schroedinger's Cat' experiment to test semiclassical quantum gravity, and the gravitational single slit experiment to demonstrate the wave-particle duality for photons, are both described and discussed. (U.K.)

  7. Arctic Ocean gravity, geoid and sea-ice freeboard heights from ICESat and GRACE

    DEFF Research Database (Denmark)

    Forsberg, René; Skourup, Henriette

    2005-01-01

    Gravity Project in combination with GRACE gravity field models to derive an improved Arctic geoid model. This model is then used to convert ICESat measurements to sea-ice freeboard heights with a coarse lowest-level surface method. The derived freeboard heights show a good qualitative agreement...... all major tectonic features of the Arctic Ocean, and has an accuracy of 6 mGal compared to recent airborne gravity data, illustrating the usefulness of ICESat data for gravity field determination....

  8. CALIOPE airborne CO{sub 2} DIAL (CACDI) system design

    Energy Technology Data Exchange (ETDEWEB)

    Mietz, D.; Archuleta, B.; Archuleta, J. [and others

    1997-09-01

    Los Alamos National Laboratory is currently developing an airborne CO{sub 2} Differential Absorption Lidar (DIAL) system based on second generation technology demonstrated last summer at NTS. The CALIOPE Airborne CO{sub 2} DIAL (CACDI) system requirements have been compiled based on the mission objectives and SONDIAL model trade studies. Subsystem designs have been developed based on flow down from these system requirements, as well as experience gained from second generation ground tests and N-ABLE (Non-proliferation AirBorne Lidar Experiments) airborne experiments. This paper presents the CACDI mission objectives, system requirements, the current subsystem design, and provides an overview of the airborne experimental plan.

  9. Analogue Gravity

    Directory of Open Access Journals (Sweden)

    Carlos Barceló

    2011-05-01

    Full Text Available Analogue gravity is a research programme which investigates analogues of general relativistic gravitational fields within other physical systems, typically but not exclusively condensed matter systems, with the aim of gaining new insights into their corresponding problems. Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.

  10. Trace Gas Measurements from the GeoTASO and GCAS Airborne Instruments: An Instrument and Algorithm Test-Bed for Air Quality Observations from Geostationary Orbit

    Science.gov (United States)

    Nowlan, C. R.; Liu, X.; Janz, S. J.; Leitch, J. W.; Al-Saadi, J. A.; Chance, K.; Cole, J.; Delker, T.; Follette-Cook, M. B.; Gonzalez Abad, G.; Good, W. S.; Kowalewski, M. G.; Loughner, C.; Pickering, K. E.; Ruppert, L.; Soo, D.; Szykman, J.; Valin, L.; Zoogman, P.

    2016-12-01

    The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) and the GEO-CAPE Airborne Simulator (GCAS) instruments are pushbroom sensors capable of making remote sensing measurements of air quality and ocean color. Originally developed as test-bed instruments for the Geostationary Coastal and Air Pollution Events (GEO-CAPE) decadal survey, these instruments are now also part of risk reduction for the upcoming Tropospheric Emissions: Monitoring of Pollution (TEMPO) and Geostationary Environment Monitoring Spectrometer (GEMS) geostationary satellite missions, and will provide validation capabilities after the satellite instruments are in orbit. GeoTASO and GCAS flew on two different aircraft in their first intensive air quality field campaigns during the DISCOVER-AQ missions over Texas in 2013 and Colorado in 2014. GeoTASO was also deployed in 2016 during the KORUS-AQ field campaign to make measurements of trace gases and aerosols over Korea. GeoTASO and GCAS collect spectra of backscattered solar radiation in the UV and visible that can be used to derive 2-D maps of trace gas columns below the aircraft at spatial resolutions on the order of 250 x 500 m. We present spatially resolved maps of trace gas retrievals of ozone, nitrogen dioxide, formaldehyde and sulfur dioxide over urban areas and power plants from flights during the field campaigns, and comparisons with data from ground-based spectrometers, in situ monitoring instruments, and satellites.

  11. Tumbleweeds and airborne gravitational noise sources for LIGO

    International Nuclear Information System (INIS)

    Creighton, Teviet

    2008-01-01

    The relative positions of the test masses in gravitational-wave detectors will be influenced not only by astrophysical gravitational waves, but also by the fluctuating Newtonian gravitational forces of moving masses in the ground and air around the detector. These effects are often referred to as gravity gradient noise. This paper considers the effects of gravity gradients from density perturbations in the atmosphere, and from massive airborne objects near the detector. These have been discussed previously by Saulson (1984 Phys. Rev. D 30 732), who considered the effects of background acoustic pressure waves and of massive objects moving smoothly past the interferometer; the gravity gradients he predicted would be too small to be of serious concern even for advanced interferometric gravitational-wave detectors. In this paper, I revisit these phenomena, considering transient atmospheric shocks, and estimating the effects of sound waves or objects colliding with the ground or buildings around the test masses. I also consider another source of atmospheric density fluctuations: temperature perturbations that are advected past the detector by the wind. I find that background acoustic noise and temperature fluctuations still produce gravity gradient noise that is below the noise floor even of advanced interferometric detectors, although temperature perturbations carried along non-laminar streamlines could produce noise that is within an order of magnitude of the projected noise floor at 10 Hz. A definitive study of this effect may require better models of the wind flow past a given instrument. I also find that transient shockwaves in the atmosphere could potentially produce large spurious signals, with signal-to-noise ratios in the hundreds in an advanced interferometric detector. These signals could be vetoed by means of acoustic sensors outside of the buildings. Massive wind-borne objects such as tumbleweeds could also produce gravity gradient signals with signal

  12. Preliminary appraisal of gravity and magnetic data at Syncline Ridge, Western Yucca Flat, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    Ponce, D.A.; Hanna, W.F.

    1982-01-01

    A gravity and magnetic study of the Syncline Ridge area was conducted as part of an investigation of argillite rocks of the Eleana Formation under consideration as a medium for the possible storage of high-level radioactive waste. Bouguer gravity anomaly, low-level aeromagnetic anomaly, density, and magnetization data collectively indicate the following, relative to the Eleana Formation, the principal target of the investigation: (1) in an area extending northwestward from Mine Mountain, through Syncline Ridge, to the Eleana Range, the Eleana Formation, where not exposed, occurs at depths of less than approx. 200 m, except for a small region of exposed older Paleozoic rocks; (2) in the region of shallowly buried Eleana Formation, occurrences of volcanic rock cover are delineated by low-level aeromagnetic anomaly data, which also discriminate normally polarized from reversely polarized tuff units; and (3) selective detection of high-quartz argillite relative to low-quartz argillite using surface gravity data is not feasible if the high-quartz and low-quartz varieties are intimately interbedded, as observed in boreholes. 4 figures, 2 tables

  13. Quantum Gravity

    International Nuclear Information System (INIS)

    Giribet, G E

    2005-01-01

    Claus Kiefer presents his book, Quantum Gravity, with his hope that '[the] book will convince readers of [the] outstanding problem [of unification and quantum gravity] and encourage them to work on its solution'. With this aim, the author presents a clear exposition of the fundamental concepts of gravity and the steps towards the understanding of its quantum aspects. The main part of the text is dedicated to the analysis of standard topics in the formulation of general relativity. An analysis of the Hamiltonian formulation of general relativity and the canonical quantization of gravity is performed in detail. Chapters four, five and eight provide a pedagogical introduction to the basic concepts of gravitational physics. In particular, aspects such as the quantization of constrained systems, the role played by the quadratic constraint, the ADM decomposition, the Wheeler-de Witt equation and the problem of time are treated in an expert and concise way. Moreover, other specific topics, such as the minisuperspace approach and the feasibility of defining extrinsic times for certain models, are discussed as well. The ninth chapter of the book is dedicated to the quantum gravitational aspects of string theory. Here, a minimalistic but clear introduction to string theory is presented, and this is actually done with emphasis on gravity. It is worth mentioning that no hard (nor explicit) computations are presented, even though the exposition covers the main features of the topic. For instance, black hole statistical physics (within the framework of string theory) is developed in a pedagogical and concise way by means of heuristical arguments. As the author asserts in the epilogue, the hope of the book is to give 'some impressions from progress' made in the study of quantum gravity since its beginning, i.e., since the end of 1920s. In my opinion, Kiefer's book does actually achieve this goal and gives an extensive review of the subject. (book review)

  14. Airborne Gravimetry Survey for the Marine Area of the United Arab Emirates

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Alshamsi, Adel

    2012-01-01

    The Military Survey Department (MSD) of the United Arab Emirates (UAE) undertook an airborne gravity survey project for the marine area of the country in 2009, especially to strengthen the marine and coastal geoid in the near-shore regions. For the airborne gravity survey, 5 km spacing coast...... flight speed of 170 knots and a typical flight elevation of 900-1500 m, depending on weather conditions and topography. Gravity was measured with a ZLS-modified LaCoste and Romberg gravimeter (S-99), augmented with a Honeywell strap-down inertial navigation system unit. The estimated accuracy...

  15. Airborne Compositae dermatitis

    DEFF Research Database (Denmark)

    Christensen, Lars Porskjær; Jakobsen, Henrik Byrial; Paulsen, E.

    1999-01-01

    The air around intact feverfew (Tanacetum parthenium) plants was examined for the presence of airborne parthenolide and other potential allergens using a high-volume air sampler and a dynamic headspace technique. No particle-bound parthenolide was detected in the former. Among volatiles emitted f...... for airborne Compositae dermatitis. Potential allergens were found among the emitted monoterpenes and their importance in airborne Compositae dermatitis is discussed....

  16. Is Gravity an Entropic Force?

    Directory of Open Access Journals (Sweden)

    Shan Gao

    2011-04-01

    Full Text Available The remarkable connections between gravity and thermodynamics seem to imply that gravity is not fundamental but emergent, and in particular, as Verlinde suggested, gravity is probably an entropic force. In this paper, we will argue that the idea of gravity as an entropic force is debatable. It is shown that there is no convincing analogy between gravity and entropic force in Verlinde’s example. Neither holographic screen nor test particle satisfies all requirements for the existence of entropic force in a thermodynamics system. Furthermore, we show that the entropy increase of the screen is not caused by its statistical tendency to increase entropy as required by the existence of entropic force, but in fact caused by gravity. Therefore, Verlinde’s argument for the entropic origin of gravity is problematic. In addition, we argue that the existence of a minimum size of spacetime, together with the Heisenberg uncertainty principle in quantum theory, may imply the fundamental existence of gravity as a geometric property of spacetime. This may provide a further support for the conclusion that gravity is not an entropic force.

  17. Simulating Gravity

    Science.gov (United States)

    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. Cellular gravity

    NARCIS (Netherlands)

    F.C. Gruau; J.T. Tromp (John)

    1999-01-01

    textabstractWe consider the problem of establishing gravity in cellular automata. In particular, when cellular automata states can be partitioned into empty, particle, and wall types, with the latter enclosing rectangular areas, we desire rules that will make the particles fall down and pile up on

  19. Airborne Tactical Crossload Planner

    Science.gov (United States)

    2017-12-01

    Regiment AGL above ground level AO area of operation APA American psychological association ASOP airborne standard operating procedure A/C aircraft...awarded a research contract to develop a tactical crossload tool. [C]omputer assisted Airborne Planning Application ( APA ) that provides a

  20. Testing general relativity and alternative theories of gravity with space-based atomic clocks and atom interferometers

    Directory of Open Access Journals (Sweden)

    Bondarescu Ruxandra

    2015-01-01

    Full Text Available The successful miniaturisation of extremely accurate atomic clocks and atom interferometers invites prospects for satellite missions to perform precision experiments. We discuss the effects predicted by general relativity and alternative theories of gravity that can be detected by a clock, which orbits the Earth. Our experiment relies on the precise tracking of the spacecraft using its observed tick-rate. The spacecraft’s reconstructed four-dimensional trajectory will reveal the nature of gravitational perturbations in Earth’s gravitational field, potentially differentiating between different theories of gravity. This mission can measure multiple relativistic effects all during the course of a single experiment, and constrain the Parametrized Post-Newtonian Parameters around the Earth. A satellite carrying a clock of fractional timing inaccuracy of Δ f / f ∼ 10−16 in an elliptic orbit around the Earth would constrain the PPN parameters |β − 1|, |γ − 1| ≲ 10−6. We also briefly review potential constraints by atom interferometers on scalar tensor theories and in particular on Chameleon and dilaton models.

  1. Quantum gravity

    International Nuclear Information System (INIS)

    Isham, C.

    1989-01-01

    Gravitational effects are seen as arising from a curvature in spacetime. This must be reconciled with gravity's apparently passive role in quantum theory to achieve a satisfactory quantum theory of gravity. The development of grand unified theories has spurred the search, with forces being of equal strength at a unification energy of 10 15 - 10 18 GeV, with the ''Plank length'', Lp ≅ 10 -35 m. Fundamental principles of general relativity and quantum mechanics are outlined. Gravitons are shown to have spin-0, as mediators of gravitation force in the classical sense or spin-2 which are related to the quantisation of general relativity. Applying the ideas of supersymmetry to gravitation implies partners for the graviton, especially the massless spin 3/2 fermion called a gravitino. The concept of supersymmetric strings is introduced and discussed. (U.K.)

  2. Quantum gravity

    International Nuclear Information System (INIS)

    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

  3. Is nonrelativistic gravity possible?

    International Nuclear Information System (INIS)

    Kocharyan, A. A.

    2009-01-01

    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.

  4. Airborne Deployment of a High Resolution PTR-ToF-MS to Characterize Non-methane Organic Gases in Wildfire Smoke: A Pilot Study During WE-CAN Test Flights

    Science.gov (United States)

    Permar, W.; Hu, L.; Fischer, E. V.

    2017-12-01

    Despite being the second largest primary source of tropospheric volatile organic compounds (VOCs), biomass burning is poorly understood relative to other sources due in part to its large variability and the difficulty inherent to sampling smoke. In light of this, several field campaigns are planned to better characterize wildfire plume emissions and chemistry through airborne sampling of smoke plumes. As part of this effort, we will deploy a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) on the NSF/NCAR C-130 research aircraft during the collaborative Western wildfire Experiment for Cloud chemistry, Aerosol absorption and Nitrogen (WE-CAN) mission. PTR-ToF-MS is well suited for airborne measurements of VOC in wildfire smoke plumes due to its ability to collect real time, high-resolution data for the full mass range of ionizable organic species, many of which remain uncharacterized or unidentified. In this work, we will report on our initial measurements from the WE-CAN test flights in September 2017. We will also discuss challenges associated with deploying the instrument for airborne missions targeting wildfire smoke and goals for further study in WE-CAN 2018.

  5. Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory

    International Nuclear Information System (INIS)

    Chan, H.A.; Paik, H.J.

    1987-01-01

    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. Noncommutative gravity

    International Nuclear Information System (INIS)

    Schupp, P.

    2007-01-01

    Heuristic arguments suggest that the classical picture of smooth commutative spacetime should be replaced by some kind of quantum / noncommutative geometry at length scales and energies where quantum as well as gravitational effects are important. Motivated by this idea much research has been devoted to the study of quantum field theory on noncommutative spacetimes. More recently the focus has started to shift back to gravity in this context. We give an introductory overview to the formulation of general relativity in a noncommutative spacetime background and discuss the possibility of exact solutions. (author)

  7. Mars - Hellas Planitia gravity analysis

    Science.gov (United States)

    Sjogren, W. L.; Wimberley, R. N.

    1981-01-01

    Doppler radio tracking data from Viking Orbiter 1 has provided new detailed observations of gravity variations over Hellas Planitia. Line-of-sight Bouguer gravity definitely indicates that isostatic adjustment has occurred. Two theoretical models were tested to obtain fits to the gravity data. Results for a surface deficit model, and a model with a surface deficit and a mass excess at depth are displayed. The mass-at-depth model produced very marked improvement in the data fit as compared to the surface deficit model. The optimum depth for the mass excess is 130 km.

  8. Airborne Magnetic Trackline Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) receive airborne magnetic survey data from US and non-US...

  9. Conformal Gravity

    International Nuclear Information System (INIS)

    Hooft, G.

    2012-01-01

    The dynamical degree of freedom for the gravitational force is the metric tensor, having 10 locally independent degrees of freedom (of which 4 can be used to fix the coordinate choice). In conformal gravity, we split this field into an overall scalar factor and a nine-component remainder. All unrenormalizable infinities are in this remainder, while the scalar component can be handled like any other scalar field such as the Higgs field. In this formalism, conformal symmetry is spontaneously broken. An imperative demand on any healthy quantum gravity theory is that black holes should be described as quantum systems with micro-states as dictated by the Hawking-Bekenstein theory. This requires conformal symmetry that may be broken spontaneously but not explicitly, and this means that all conformal anomalies must cancel out. Cancellation of conformal anomalies yields constraints on the matter sector as described by some universal field theory. Thus black hole physics may eventually be of help in the construction of unified field theories. (author)

  10. Airborne Particulate Threat Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  11. Southern Africa Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data base (14,559 records) was received in January 1986. Principal gravity parameters include elevation and observed gravity. The observed gravity values are...

  12. NGS Absolute Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NGS Absolute Gravity data (78 stations) was received in July 1993. Principal gravity parameters include Gravity Value, Uncertainty, and Vertical Gradient. The...

  13. Granular Superconductors and Gravity

    Science.gov (United States)

    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.

  14. Air ICP uses for instantaneous monitoring of airborne pollutants

    International Nuclear Information System (INIS)

    Thouzeau, F.; Birolleau, J.C.; Fieni, J.M.; Bergey, C.

    1987-01-01

    Recently the development of a pure AIR-ICP which breathes in and excites the analysed air without sample dilution, allowed the application of this technique to the real time analysis of airborne metallic pollutants. First results obtained on airborne Beryllium in a laboratory and a test-site apparatus are presented in this paper

  15. Newtonian gravity in loop quantum gravity

    OpenAIRE

    Smolin, Lee

    2010-01-01

    We apply a recent argument of Verlinde to loop quantum gravity, to conclude that Newton's law of gravity emerges in an appropriate limit and setting. This is possible because the relationship between area and entropy is realized in loop quantum gravity when boundaries are imposed on a quantum spacetime.

  16. Full Tensor Gradient of Simulated Gravity Data for Prospect Scale Delineation

    Directory of Open Access Journals (Sweden)

    Hendra Grandis

    2014-07-01

    Full Text Available Gravity gradiometry measurement allows imaging of anomalous sources in more detail than conventional gravity data. The availability of this new technique is limited to airborne gravity surveys using very specific instrumentation. In principle, the gravity gradients can be calculated from the vertical component of the gravity commonly measured in a ground-based gravity survey. We present a calculation of the full tensor gradient (FTG of the gravity employing the Fourier transformation. The calculation was applied to synthetic data associated with a simple block model and also with a more realistic model. The latter corresponds to a 3D model in which a thin coal layer is embedded in a sedimentary environment. Our results show the utility of the FTG of the gravity for prospect scale delineation.

  17. Modeling hurricane evacuation traffic : testing the gravity and intervening opportunity models as models of destination choice in hurricane evacuation.

    Science.gov (United States)

    2006-09-01

    The test was conducted by estimating the models on a portion of evacuation data from South Carolina following Hurricane Floyd, and then observing how well the models reproduced destination choice at the county level on the remaining data. The tests s...

  18. Testing joint inversion techniques of gravity data and cosmic ray muon flux at a well-characterized site for use in the detection of subsurface density structures beneath volcanoes.

    Science.gov (United States)

    Cosburn, K.; Roy, M.; Rowe, C. A.; Guardincerri, E.

    2017-12-01

    Obtaining accurate static and time-dependent shallow subsurface density structure beneath volcanic, hydrogeologic, and tectonic targets can help illuminate active processes of fluid flow and magma transport. A limitation of using surface gravity measurements for such imaging is that these observations are vastly underdetermined and non-unique. In order to hone in on a more accurate solution, other data sets are needed to provide constraints, typically seismic or borehole observations. The spatial resolution of these techniques, however, is relatively poor, and a novel solution to this problem in recent years has been to use attenuation of the cosmic ray muon flux, which provides an independent constraint on density. In this study we present a joint inversion of gravity and cosmic ray muon flux observations to infer the density structure of a target rock volume at a well-characterized site near Los Alamos, New Mexico, USA. We investigate the shallow structure of a mesa formed by the Quaternary ash-flow tuffs on the Pajarito Plateau, flanking the Jemez volcano in New Mexico. Gravity measurements were made using a Lacoste and Romberg D meter on the surface of the mesa and inside a tunnel beneath the mesa. Muon flux measurements were also made at the mesa surface and at various points within the same tunnel using a muon detector having an acceptance region of 45 degrees from the vertical and a track resolution of several milliradians. We expect the combination of muon and gravity data to provide us with enhanced resolution as well as the ability to sense deeper structures in our region of interest. We use Bayesian joint inversion techniques on the gravity-muon dataset to test these ideas, building upon previous work using gravity inversion alone to resolve density structure in our study area. Both the regional geology and geometry of our study area is well-known and we assess the inferred density structure from our gravity-muon joint inversion within this known

  19. DenInv3D: a geophysical software for three-dimensional density inversion of gravity field data

    Science.gov (United States)

    Tian, Yu; Ke, Xiaoping; Wang, Yong

    2018-04-01

    This paper presents a three-dimensional density inversion software called DenInv3D that operates on gravity and gravity gradient data. The software performs inversion modelling, kernel function calculation, and inversion calculations using the improved preconditioned conjugate gradient (PCG) algorithm. In the PCG algorithm, due to the uncertainty of empirical parameters, such as the Lagrange multiplier, we use the inflection point of the L-curve as the regularisation parameter. The software can construct unequally spaced grids and perform inversions using such grids, which enables changing the resolution of the inversion results at different depths. Through inversion of airborne gradiometry data on the Australian Kauring test site, we discovered that anomalous blocks of different sizes are present within the study area in addition to the central anomalies. The software of DenInv3D can be downloaded from http://159.226.162.30.

  20. Apollo-Soyuz test project. Volume 1: Astronomy, earth atmosphere and gravity field, life sciences, and materials processing

    Science.gov (United States)

    1977-01-01

    The joint U.S.-USSR experiments and the U.S. conducted unilateral experiments performed during the Apollo Soyuz Test Project are described. Scientific concepts and experiment design and operation are discussed along with scientific results of postflight analysis.

  1. Active airborne contamination control using electrophoresis

    International Nuclear Information System (INIS)

    Veatch, B.D.

    1994-01-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ''cold,'' or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications

  2. Cosmological footprints of loop quantum gravity.

    Science.gov (United States)

    Grain, J; Barrau, A

    2009-02-27

    The primordial spectrum of cosmological tensor perturbations is considered as a possible probe of quantum gravity effects. Together with string theory, loop quantum gravity is one of the most promising frameworks to study quantum effects in the early universe. We show that the associated corrections should modify the potential seen by gravitational waves during the inflationary amplification. The resulting power spectrum should exhibit a characteristic tilt. This opens a new window for cosmological tests of quantum gravity.

  3. Superconducting gravity gradiometer for sensitive gravity measurements. II. Experiment

    International Nuclear Information System (INIS)

    Chan, H.A.; Moody, M.V.; Paik, H.J.

    1987-01-01

    A sensitive superconducting gravity gradiometer has been constructed and tested. Coupling to gravity signals is obtained by having two superconducting proof masses modulate magnetic fields produced by persistent currents. The induced electrical currents are differenced by a passive superconducting circuit coupled to a superconducting quantum interference device. The experimental behavior of this device has been shown to follow the theoretical model closely in both signal transfer and noise characteristics. While its intrinsic noise level is shown to be 0.07 E Hz/sup -1/2/ (1 Eequivalent10/sup -9/ sec/sup -2/), the actual performance of the gravity gradiometer on a passive platform has been limited to 0.3--0.7 E Hz/sup -1/2/ due to its coupling to the environmental noise. The detailed structure of this excess noise is understood in terms of an analytical error model of the instrument. The calibration of the gradiometer has been obtained by two independent methods: by applying a linear acceleration and a gravity signal in two different operational modes of the instrument. This device has been successfully operated as a detector in a new null experiment for the gravitational inverse-square law. In this paper we report the design, fabrication, and detailed test results of the superconducting gravity gradiometer. We also present additional theoretical analyses which predict the specific dynamic behavior of the gradiometer and of the test

  4. Orion Crew Module / Service Module Structural Weight and Center of Gravity Simulator and Vehicle Motion Simulator Hoist Structure for Orion Service Module Umbilical Testing

    Science.gov (United States)

    Ascoli, Peter A.; Haddock, Michael H.

    2014-01-01

    An Orion Crew Module Service Module Structural Weight and Center of Gravity Simulator and a Vehicle Motion Simulator Hoist Structure for Orion Service Module Umbilical Testing were designed during a summer 2014 internship in Kennedy Space Centers Structures and Mechanisms Design Branch. The simulator is a structure that supports ballast, which will be integrated into an existing Orion mock-up to simulate the mass properties of the Exploration Mission-1 flight vehicle in both fueled and unfueled states. The simulator mimics these configurations through the use of approximately 40,000 lbf of steel and water ballast, and a steel support structure. Draining four water tanks, which house the water ballast, transitions the simulator from the fueled to unfueled mass properties. The Ground Systems Development and Operations organization will utilize the simulator to verify and validate equipment used to maneuver and transport the Orion spacecraft in its fueled and unfueled configurations. The second design comprises a cantilevered tripod hoist structure that provides the capability to position a large Orion Service Module Umbilical in proximity to the Vehicle Motion Simulator. The Ground Systems Development and Operations organization will utilize the Vehicle Motion Simulator, with the hoist structure attached, to test the Orion Service Module Umbilical for proper operation prior to installation on the Mobile Launcher. Overall, these two designs provide NASA engineers viable concepts worthy of fabricating and placing into service to prepare for the launch of Orion in 2017.

  5. The Cause of Gravity

    OpenAIRE

    Byrne, Michael

    1999-01-01

    Einstein said that gravity is an acceleration like any other acceleration. But gravity causes relativistic effects at non-relativistic speeds; so gravity could have relativistic origins. And since the strong force is thought to cause most of mass, and mass is proportional to gravity; the strong force is therefore also proportional to gravity. The strong force could thus cause relativistic increases of mass through the creation of virtual gluons; along with a comparable contraction of space ar...

  6. Antimatter, the SME, and gravity

    Energy Technology Data Exchange (ETDEWEB)

    Tasson, Jay D., E-mail: jtasson@carleton.edu [Whitman College, Department of Physics (United States)

    2012-12-15

    A general field-theoretic framework for the analysis of CPT and Lorentz violation is provided by the Standard-Model Extension (SME). This work discusses a number SME-based proposals for tests of CPT and Lorentz symmetry, including antihydrogen spectroscopy and antimatter gravity tests.

  7. Antimatter, the SME, and gravity

    International Nuclear Information System (INIS)

    Tasson, Jay D.

    2012-01-01

    A general field-theoretic framework for the analysis of CPT and Lorentz violation is provided by the Standard-Model Extension (SME). This work discusses a number SME-based proposals for tests of CPT and Lorentz symmetry, including antihydrogen spectroscopy and antimatter gravity tests.

  8. Field tests of a new, extractive, airborne 1.4 μm -TDLAS hygrometer (SEALDH-I) on a Learjet 35A

    Science.gov (United States)

    Buchholz, Bernhard; Ebert, Volker

    2013-04-01

    A highly accurate and precise quantification of atmospheric humidity is a prerequisite for cloud studies as well as for environmental models in order to get a deeper understanding of physical processes and effects. On the one hand numerous trace gases measurements in airborne "laboratories" have to be corrected for water vapor influence; on the other hand satellite measurements have to be validated by in-situ H2O measurements on aircrafts. The vast majority of the airborne hygrometers require a precise and frequent sensor calibration in order to ensure a sufficient performance. UT/LS sensors in particular are often calibrated before and after each individual flight. But even this might not be sufficient which explains why recently in-flight calibrations are becoming more common. Nevertheless all calibrated sensors completely depend on the performance of the water standard used for calibration. Therefore it remains an open question if in-flight calibrations are the way to go: They also might suffer from inflight disturbances and they would need validation during flight conditions. Water calibrations at low humidity are even more complicated due to the strong water adsorption and the resulting sampling problems. An abstention from calibration would avoid many of these problems. In addition, calibration free sensors are much easier to debug as they can hardly have errors which can be hidden by calibration parameters (such as leaks, etc.). Robust cal-free sensors should therefore perform more stable in flight when the sensors boundary conditions might change. The situation can be improved further with extractive cal-free sensors as the boundary condition in measurement volume (pressure, temperature, path length, flow pattern, etc.), i.e. in an extractive cell, are much better controlled than for an open path sensor. Further cal-free extractive sensors can be designed maintain its integrity when attaching and detaching it from the carrier (airplane). This makes it much

  9. New approach to airborne monitoring of radioactive pollution

    International Nuclear Information System (INIS)

    Hoeschl, V.; Jurza, P.; Pavlik, B.

    1997-01-01

    The use of remote sensing methods in the monitoring of an environment is increasing. The best results are obtained when various types of exploration methods are available. This paper presents the use of airborne gamma ray methods, which can be included in a wide scope of works related to environmental problems. It may concern uranium mining areas, areas surrounding various nuclear facilities or areas of Chernobyl fallout. Gamma ray spectrometry data can be combined with airborne magnetic, surface gravity and satellite imagery data to obtain maximum information in data output. Airborne geophysics is able to detect and delineate radioactive contamination and to find important geological trends defining the geological structure of the monitored area. Our company PICODAS Prague Ltd. introduces new sophisticated airborne instrumentation as well as up-to-date data processing and data presentation techniques. In the Czech Cretaceous, a long term project, ''The Structurally-tectonic Survey of the South-West Foreland of the Straz Deposit'' has been undertaken, concerning the ecological load on the environment, especially the pollution of the underground water level horizons due to uranium mining in that area. The major interest is the complicated tectonic structure which interferes heavily with the hydrogeological situation of the region. The paper presents the results of airborne surveys and the interpretation of other geophysical data from the surroundings of Straz pod Ralskem and from Karlovy Vary. (author)

  10. Topics in quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Lamon, Raphael

    2010-06-29

    . Furthermore, we succeed in solving the quantum Gauss constraint. In the second part of the thesis we introduce some aspects of phenomenological quantum gravity and their possible detectable signatures. The goal of phenomenological quantum gravity is to derive conclusions and make predictions from expected characteristics of a full theory of quantum gravity. One possibility is an energy-dependent speed of light arising from a quantized space such that the propagation time of two photons differs. However, the amount of these corrections is very small such that only cosmological distances can be considered. Gamma-ray bursts (GRB) are ideal candidates as they are short but very luminous bursts of gamma-rays taking place at distances billions of light-years away. We study GRBs detected by the European satellite INTEGRAL and develop a new method to analyze unbinned data. A {chi}{sup 2}-test will provide a lower bound for quantum gravity corrections, which will be nevertheless well below the Planck mass. Then we shall study the sensibility of NASA's new satellite Fermi Gamma-ray Space Telescope and conclude that it is well suited to detect corrections. This prediction has just been confirmed when Fermi detected a very energetic photon emanating from GRB 090510 which highly constrains models with linear corrections to the speed of light. However, as it is shown at the end of this thesis, more bursts are needed in order to definitely falsify such models. (orig.)

  11. Topics in quantum gravity

    International Nuclear Information System (INIS)

    Lamon, Raphael

    2010-01-01

    succeed in solving the quantum Gauss constraint. In the second part of the thesis we introduce some aspects of phenomenological quantum gravity and their possible detectable signatures. The goal of phenomenological quantum gravity is to derive conclusions and make predictions from expected characteristics of a full theory of quantum gravity. One possibility is an energy-dependent speed of light arising from a quantized space such that the propagation time of two photons differs. However, the amount of these corrections is very small such that only cosmological distances can be considered. Gamma-ray bursts (GRB) are ideal candidates as they are short but very luminous bursts of gamma-rays taking place at distances billions of light-years away. We study GRBs detected by the European satellite INTEGRAL and develop a new method to analyze unbinned data. A χ 2 -test will provide a lower bound for quantum gravity corrections, which will be nevertheless well below the Planck mass. Then we shall study the sensibility of NASA's new satellite Fermi Gamma-ray Space Telescope and conclude that it is well suited to detect corrections. This prediction has just been confirmed when Fermi detected a very energetic photon emanating from GRB 090510 which highly constrains models with linear corrections to the speed of light. However, as it is shown at the end of this thesis, more bursts are needed in order to definitely falsify such models. (orig.)

  12. Evaluation and Comparison of the Processing Methods of Airborne Gravimetry Concerning the Errors Effects on Downward Continuation Results: Case Studies in Louisiana (USA) and the Tibetan Plateau (China).

    Science.gov (United States)

    Zhao, Qilong; Strykowski, Gabriel; Li, Jiancheng; Pan, Xiong; Xu, Xinyu

    2017-05-25

    Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The

  13. Evaluation and Comparison of the Processing Methods of Airborne Gravimetry Concerning the Errors Effects on Downward Continuation Results: Case Studies in Louisiana (USA) and the Tibetan Plateau (China)

    Science.gov (United States)

    Zhao, Q.

    2017-12-01

    Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The

  14. In what sense a neutron star-black hole binary is the holy grail for testing gravity?

    International Nuclear Information System (INIS)

    Bagchi, Manjari; Torres, Diego F.

    2014-01-01

    Pulsars in binary systems have been very successful to test the validity of general relativity in the strong field regime [1-4]. So far, such binaries include neutron star-white dwarf (NS-WD) and neutron star-neutron star (NS-NS) systems. It is commonly believed that a neutron star-black hole (NS-BH) binary will be much superior for this purpose. But in what sense is this true? Does it apply to all possible deviations?

  15. Global Earth Structure Recovery from State-of-the-art Models of the Earth's Gravity Field and Additional Geophysical Information

    NARCIS (Netherlands)

    Hamayun, H.

    2014-01-01

    Currently, a tremendous improvement is observed in the accuracy and spatial resolution of global Earth’s gravity field models. This improvement is achieved due to using various new data, including those from satellite gravimetry missions (CHAMP, GRACE, and GOCE); terrestrial and airborne gravity

  16. South African Airborne Operations

    African Journals Online (AJOL)

    South Africa carried out numerous airborne operations during the latter part .... It was a lesson the French had learned and were learning in Indo-China and ..... South African government, concerned that the conflict would spill across their northern border, ...... the Super Frelon and it was an outstanding helicopter at sea level.

  17. Chiral gravity, log gravity, and extremal CFT

    International Nuclear Information System (INIS)

    Maloney, Alexander; Song Wei; Strominger, Andrew

    2010-01-01

    We show that the linearization of all exact solutions of classical chiral gravity around the AdS 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.

  18. New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica.

    Science.gov (United States)

    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

    2016-01-28

    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 km 2 , which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated levelling of the different gravity datasets 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 towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.

  19. Spin Entanglement Witness for Quantum Gravity.

    Science.gov (United States)

    Bose, Sougato; Mazumdar, Anupam; Morley, Gavin W; Ulbricht, Hendrik; Toroš, Marko; Paternostro, Mauro; Geraci, Andrew A; Barker, Peter F; Kim, M S; Milburn, Gerard

    2017-12-15

    Understanding gravity in the framework of quantum mechanics is one of the great challenges in modern physics. However, the lack of empirical evidence has lead to a debate on whether gravity is a quantum entity. Despite varied proposed probes for quantum gravity, it is fair to say that there are no feasible ideas yet to test its quantum coherent behavior directly in a laboratory experiment. Here, we introduce an idea for such a test based on the principle that two objects cannot be entangled without a quantum mediator. We show that despite the weakness of gravity, the phase evolution induced by the gravitational interaction of two micron size test masses in adjacent matter-wave interferometers can detectably entangle them even when they are placed far apart enough to keep Casimir-Polder forces at bay. We provide a prescription for witnessing this entanglement, which certifies gravity as a quantum coherent mediator, through simple spin correlation measurements.

  20. Geophex Airborne Unmanned Survey System

    International Nuclear Information System (INIS)

    Won, I.L.; Keiswetter, D.

    1995-01-01

    Ground-based surveys place personnel at risk due to the proximity of buried unexploded ordnance (UXO) items or by exposure to radioactive materials and hazardous chemicals. The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide stand-off capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected. The Geophex Airborne Unmanned Survey System (GAUSS) is designed to detect and locate small-scale anomalies at hazardous sites using magnetic and electromagnetic survey techniques. The system consists of a remotely-piloted, radio-controlled, model helicopter (RCH) with flight computer, light-weight geophysical sensors, an electronic positioning system, a data telemetry system, and a computer base-station. The report describes GAUSS and its test results

  1. Geophex Airborne Unmanned Survey System

    Energy Technology Data Exchange (ETDEWEB)

    Won, I.L.; Keiswetter, D.

    1995-12-31

    Ground-based surveys place personnel at risk due to the proximity of buried unexploded ordnance (UXO) items or by exposure to radioactive materials and hazardous chemicals. The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide stand-off capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected. The Geophex Airborne Unmanned Survey System (GAUSS) is designed to detect and locate small-scale anomalies at hazardous sites using magnetic and electromagnetic survey techniques. The system consists of a remotely-piloted, radio-controlled, model helicopter (RCH) with flight computer, light-weight geophysical sensors, an electronic positioning system, a data telemetry system, and a computer base-station. The report describes GAUSS and its test results.

  2. ngVLA Key Science Goal 4: Using Pulsars in the Galactic Center as Fundamental Tests of Gravity

    Science.gov (United States)

    Bower, Geoffrey C.; Chatterjee, Shami; Cordes, James; Demorest, Paul; Dexter, Jason; Kramer, Michael; Lazio, Joseph; Ransom, Scott; Wharton, Robert; ngVLA Science Working Group 4

    2018-01-01

    Pulsars in the Galactic Center (GC) are important probes of general relativity (GR), star formation, stellar dynamics, stellar evolution, and the interstellar medium. A pulsar in orbit around the massive black hole in the GC, Sgr A*, has the power to provide a high-precision measurement of the black hole mass and spin in a unique regime of GR. It is sufficient to find and time a normal, slowly rotating pulsar in a reasonable orbit, in order to measure the mass of Sgr A* with a precision of 1 solar mass, to test the cosmic censorship conjecture to a precision of 0.1%, and to test the no-hair theorem to a precision of 1%. The pulsar population in the GC on scales from the inner parsec to the edge of the Central Molecular Zone (250 parsecs in diameter) can provide fresh insight into the complex processes at work in this region: the characteristic age distribution of the discovered pulsars will give insight into the star formation history; millisecond pulsars can be used as acceleratormeters to probe the local gravitational potential; the observed dispersion and scattering measures (and their variability) will allow us to probe the distribution, clumpiness and other properties of the central interstellar medium, including characterization of the central magnetic field using Faraday rotation. Proper motions of young pulsars can be used to point back to regions of recent star formation and/or supernova remnants.Despite years of searching, only a handful of pulsars in the central 0.5 degrees are known. This is likely the result of strong interstellar scattering along the line of sight, which broadens individual pulses to greater width than the pulse period. Scattering effects decline as wavelength to the fourth power, implying that we require observation at higher frequencies than are typical for typical pulsar searches. The characteristic steep spectrum of pulsars, however, implies the need for greater instrumental sensitivity at higher frequencies in order to detect and

  3. Quantum W3 gravity

    International Nuclear Information System (INIS)

    Schoutens, K.; van Nieuwenhuizen, P.; State Univ. of New York, Stony Brook, NY

    1991-11-01

    We briefly review some results in the theory of quantum W 3 gravity in the chiral gauge. We compare them with similar results in the analogous but simpler cases of d = 2 induced gauge theories and d = 2 induced gravity

  4. Cadiz, California Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (32 records) were gathered by Mr. Seth I. Gutman for AridTech Inc., Denver, Colorado using a Worden Prospector gravity meter. This data base...

  5. Andes 1997 Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...

  6. DNAG Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Decade of North American Geology (DNAG) gravity grid values, spaced at 6 km, were used to produce the Gravity Anomaly Map of North America (1987; scale...

  7. Gravity wave astronomy

    International Nuclear Information System (INIS)

    Pinheiro, R.

    1979-01-01

    The properties and production of gravitational radiation are described. The prospects for their detection are considered including the Weber apparatus and gravity-wave telescopes. Possibilities of gravity-wave astronomy are noted

  8. Northern Oklahoma Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (710 records) were compiled by Professor Ahern. This data base was received in June 1992. Principal gravity parameters include latitude,...

  9. Idaho State Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (24,284 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity...

  10. Cosmological acceleration. Dark energy or modified gravity?

    International Nuclear Information System (INIS)

    Bludman, S.

    2006-05-01

    We review the evidence for recently accelerating cosmological expansion or ''dark energy'', either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any constituent Dark Energy. If constituent Dark Energy does not exist, so that our universe is now dominated by pressure-free matter, Einstein gravity must be modified at low curvature. The vacuum symmetry of any Robertson-Walker universe then characterizes Dark Gravity as low- or high-curvature modifications of Einstein gravity. The dynamics of either kind of ''dark energy'' cannot be derived from the homogeneous expansion history alone, but requires also observing the growth of inhomogeneities. Present and projected observations are all consistent with a small fine tuned cosmological constant, but also allow nearly static Dark Energy or gravity modified at cosmological scales. The growth of cosmological fluctuations will potentially distinguish between static and ''dynamic'' ''dark energy''. But, cosmologically distinguishing the Concordance Model ΛCDM from modified gravity will require a weak lensing shear survey more ambitious than any now projected. Dvali-Gabadadze-Porrati low-curvature modifications of Einstein gravity may also be detected in refined observations in the solar system (Lue and Starkman) or at the intermediate Vainstein scale (Iorio) in isolated galaxy clusters. Dark Energy's epicyclic character, failure to explain the original Cosmic Coincidence (''Why so small now?'') without fine tuning, inaccessibility to laboratory or solar system tests, along with braneworld theories, now motivate future precision solar system, Vainstein-scale and cosmological-scale studies of Dark Gravity. (Orig.)

  11. Cosmological acceleration. Dark energy or modified gravity?

    Energy Technology Data Exchange (ETDEWEB)

    Bludman, S

    2006-05-15

    We review the evidence for recently accelerating cosmological expansion or ''dark energy'', either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any constituent Dark Energy. If constituent Dark Energy does not exist, so that our universe is now dominated by pressure-free matter, Einstein gravity must be modified at low curvature. The vacuum symmetry of any Robertson-Walker universe then characterizes Dark Gravity as low- or high-curvature modifications of Einstein gravity. The dynamics of either kind of ''dark energy'' cannot be derived from the homogeneous expansion history alone, but requires also observing the growth of inhomogeneities. Present and projected observations are all consistent with a small fine tuned cosmological constant, but also allow nearly static Dark Energy or gravity modified at cosmological scales. The growth of cosmological fluctuations will potentially distinguish between static and ''dynamic'' ''dark energy''. But, cosmologically distinguishing the Concordance Model {lambda}CDM from modified gravity will require a weak lensing shear survey more ambitious than any now projected. Dvali-Gabadadze-Porrati low-curvature modifications of Einstein gravity may also be detected in refined observations in the solar system (Lue and Starkman) or at the intermediate Vainstein scale (Iorio) in isolated galaxy clusters. Dark Energy's epicyclic character, failure to explain the original Cosmic Coincidence (''Why so small now?'') without fine tuning, inaccessibility to laboratory or solar system tests, along with braneworld theories, now motivate future precision solar system, Vainstein-scale and cosmological-scale studies of Dark Gravity. (Orig.)

  12. Airborne wireless communication systems, airborne communication methods, and communication methods

    Science.gov (United States)

    Deaton, Juan D [Menan, ID; Schmitt, Michael J [Idaho Falls, ID; Jones, Warren F [Idaho Falls, ID

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  13. Strings and quantum gravity

    International Nuclear Information System (INIS)

    Vega, H.J. de

    1990-01-01

    One of the main challenges in theoretical physics today is the unification of all interactions including gravity. At present, string theories appear as the most promising candidates to achieve such a unification. However, gravity has not completely been incorporated in string theory, many technical and conceptual problems remain and a full quantum theory of gravity is still non-existent. Our aim is to properly understand strings in the context of quantum gravity. Attempts towards this are reviewed. (author)

  14. Light fermions in quantum gravity

    International Nuclear Information System (INIS)

    Eichhorn, Astrid; Gies, Holger

    2011-01-01

    We study the impact of quantum gravity, formulated as a quantum field theory of the metric, on chiral symmetry in a fermionic matter sector. Specifically we address the question of whether metric fluctuations can induce chiral symmetry breaking and bound state formation. Our results based on the functional renormalization group indicate that chiral symmetry is left intact even at strong gravitational coupling. In particular, we found that asymptotically safe quantum gravity where the gravitational couplings approach a non-Gaußian fixed point generically admits universes with light fermions. Our results thus further support quantum gravity theories built on fluctuations of the metric field such as the asymptotic-safety scenario. A study of chiral symmetry breaking through gravitational quantum effects may also serve as a significant benchmark test for other quantum gravity scenarios, since a completely broken chiral symmetry at the Planck scale would not be in accordance with the observation of light fermions in our universe. We demonstrate that this elementary observation already imposes constraints on a generic UV completion of gravity. (paper)

  15. Geometric Liouville gravity

    International Nuclear Information System (INIS)

    La, H.

    1992-01-01

    A new geometric formulation of Liouville gravity based on the area preserving diffeo-morphism is given and a possible alternative to reinterpret Liouville gravity is suggested, namely, a scalar field coupled to two-dimensional gravity with a curvature constraint

  16. Covariant w∞ gravity

    NARCIS (Netherlands)

    Bergshoeff, E.; Pope, C.N.; Stelle, K.S.

    1990-01-01

    We discuss the notion of higher-spin covariance in w∞ gravity. We show how a recently proposed covariant w∞ gravity action can be obtained from non-chiral w∞ gravity by making field redefinitions that introduce new gauge-field components with corresponding new gauge transformations.

  17. Induced quantum conformal gravity

    International Nuclear Information System (INIS)

    Novozhilov, Y.V.; Vassilevich, D.V.

    1988-11-01

    Quantum gravity is considered as induced by matter degrees of freedom and related to the symmetry breakdown in the low energy region of a non-Abelian gauge theory of fundamental fields. An effective action for quantum conformal gravity is derived where both the gravitational constant and conformal kinetic term are positive. Relation with induced classical gravity is established. (author). 15 refs

  18. Quantum Gravity Phenomenology

    OpenAIRE

    Amelino-Camelia, Giovanni

    2003-01-01

    Comment: 9 pages, LaTex. These notes were prepared while working on an invited contribution to the November 2003 issue of Physics World, which focused on quantum gravity. They intend to give a non-technical introduction (accessible to readers from outside quantum gravity) to "Quantum Gravity Phenomenology"

  19. Gravity is Geometry.

    Science.gov (United States)

    MacKeown, P. K.

    1984-01-01

    Clarifies two concepts of gravity--those of a fictitious force and those of how space and time may have geometry. Reviews the position of Newton's theory of gravity in the context of special relativity and considers why gravity (as distinct from electromagnetics) lends itself to Einstein's revolutionary interpretation. (JN)

  20. Universality of quantum gravity corrections.

    Science.gov (United States)

    Das, Saurya; Vagenas, Elias C

    2008-11-28

    We show that the existence of a minimum measurable length and the related generalized uncertainty principle (GUP), predicted by theories of quantum gravity, influence all quantum Hamiltonians. Thus, they predict quantum gravity corrections to various quantum phenomena. We compute such corrections to the Lamb shift, the Landau levels, and the tunneling current in a scanning tunneling microscope. We show that these corrections can be interpreted in two ways: (a) either that they are exceedingly small, beyond the reach of current experiments, or (b) that they predict upper bounds on the quantum gravity parameter in the GUP, compatible with experiments at the electroweak scale. Thus, more accurate measurements in the future should either be able to test these predictions, or further tighten the above bounds and predict an intermediate length scale between the electroweak and the Planck scale.

  1. Two-dimensional coherence analysis of magnetic and gravity data from the Cascer Quadrangle, Wyoming. Final report

    International Nuclear Information System (INIS)

    QEB, Inc. has completed a two-dimensional coherence analysis of gravity and magnetic data from the Casper, Wyoming NTMS quadrangle. Magnetic data from an airborne survey were reduced to produce a Residual Magnetic map, and gravity data obtained from several sources were reduced to produce a Complete Bouguer Gravity map. Both sets of data were upward continued to a plane one kilometer above the surface; and then, to make the magnetic and gravity data comparable, the magnetic data were transformed to pseudo-gravity data by the application of Poisson's relationship for rocks that are both dense and magnetic relative to the surrounding rocks. A pseudo-gravity map was then produced and an analysis made of the two-dimensional coherence between the upward continued Bouguer gravity and the pseudo-gravity data. Based on the results of the coherence analysis, digital filters were designed to either pass or reject wavelength bands with high coherence

  2. Gravity and antimatter

    International Nuclear Information System (INIS)

    Goldman, T.; Hughes, R.J.; Nieto, M.M.

    1988-01-01

    No one has ever dropped a single particle of antimatter. Yet physicists assume that it would fall to the ground just like ordinary matter. Their arguments are based on two well established ideas: the equivalence principle of gravitation and the quantum-mechanical symmetry between matter and antimatter. Today this line of reasoning is being undermined by the possibility that the first of these ideas, the principle of equivalence, may not be true. Indeed all modern attempts to include gravity with the other forces of nature in a consistent, unified quantum theory predict the existence of new gravitational-strength forces, that among other things, will violate the principle. Such effects have been seen already in recent experiments. Hence, an experiment to measure the gravitational acceleration of antimatter could be of great importance to the understanding of quantum gravity. An international team has been formed to measure the graviational acceleration of antiprotons. Such an experiment would provide an unambiquous test, if new gravitational interactions do exist. 10 figs

  3. Scales of gravity

    International Nuclear Information System (INIS)

    Dvali, Gia; Kolanovic, Marko; Nitti, Francesco; Gabadadze, Gregory

    2002-01-01

    We propose a framework in which the quantum gravity scale can be as low as 10 -3 eV. The key assumption is that the standard model ultraviolet cutoff is much higher than the quantum gravity scale. This ensures that we observe conventional weak gravity. We construct an explicit brane-world model in which the brane-localized standard model is coupled to strong 5D gravity of infinite-volume flat extra space. Because of the high ultraviolet scale, the standard model fields generate a large graviton kinetic term on the brane. This kinetic term 'shields' the standard model from the strong bulk gravity. As a result, an observer on the brane sees weak 4D gravity up to astronomically large distances beyond which gravity becomes five dimensional. Modeling quantum gravity above its scale by the closed string spectrum we show that the shielding phenomenon protects the standard model from an apparent phenomenological catastrophe due to the exponentially large number of light string states. The collider experiments, astrophysics, cosmology and gravity measurements independently point to the same lower bound on the quantum gravity scale, 10 -3 eV. For this value the model has experimental signatures both for colliders and for submillimeter gravity measurements. Black holes reveal certain interesting properties in this framework

  4. Inactivation of an enterovirus by airborne disinfectants

    Science.gov (United States)

    2013-01-01

    Background The activity of airborne disinfectants on bacteria, fungi and spores has been reported. However, the issue of the virucidal effect of disinfectants spread by fogging has not been studied thoroughly. Methods A procedure has been developed to determine the virucidal activity of peracetic acid-based airborne disinfectants on a resistant non-enveloped virus poliovirus type 1. This virus was laid on a stainless carrier. The products were spread into the room by hot fogging at 55°C for 30 minutes at a concentration of 7.5 mL.m-3. Poliovirus inoculum, supplemented with 5%, heat inactivated non fat dry organic milk, were applied into the middle of the stainless steel disc and were dried under the air flow of a class II biological safety cabinet at room temperature. The Viral preparations were recovered by using flocked swabs and were titered on Vero cells using the classical Spearman-Kärber CPE reading method, the results were expressed as TCID50.ml-1. Results The infectious titer of dried poliovirus inocula was kept at 105 TCID50.mL-1 up to 150 minutes at room temperature. Dried inocula exposed to airborne peracetic acid containing disinfectants were recovered at 60 and 120 minutes post-exposition and suspended in culture medium again. The cytotoxicity of disinfectant containing medium was eliminated through gel filtration columns. A 4 log reduction of infectious titer of dried poliovirus inocula exposed to peracetic-based airborne disinfectant was obtained. Conclusion This study demonstrates that the virucidal activity of airborne disinfectants can be tested on dried poliovirus. PMID:23587047

  5. Forage: a sensitive indicator of airborne radioactivity

    International Nuclear Information System (INIS)

    Jackson, W.M.; Noakes, J.E.; Spaulding, J.D.

    1981-01-01

    This paper presents the results of using Ge(Li) γ-ray spectroscopy to measure radioactivity concentration of forage in the vicinity of the Joseph M. Farley Nuclear Plant, Houston County, AL., over a 31/2 yr period. The report period includes 2 yr of pre-operational and 11/2 yr of operational sampling. Although the objective of forage sampling was the measurement of manmade airborne fallout radioactivity, several natural radioisotopes were also found to be present. A summary of natural radioactivity data for all samples measured during the period from August 1975 to December 1978 is given. Approximately 10 days after each of four Chinese atmospheric nuclear tests conducted during the sampling period fresh fission product fallout was measured on the forage. The information from these nuclear tests shows forage sampling to be a convenient and sensitive monitoring tool for airborne fallout radioactivity. (author)

  6. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  7. Einstein gravity emerging from quantum weyl gravity

    International Nuclear Information System (INIS)

    Zee, A.

    1983-01-01

    We advocate a conformal invariant world described by the sum of the Weyl, Dirac, and Yang-Mills action. Quantum fluctuations bring back Einstein gravity so that the long-distance phenomenology is as observed. Formulas for the induced Newton's constant and Eddington's constant are derived in quantized Weyl gravity. We show that the analogue of the trace anomaly for the Weyl action is structurally similar to that for the Yang-Mills action

  8. Airborne monitoring system

    International Nuclear Information System (INIS)

    Kadmon, Y.; Gabovitch, A.; Tirosh, D.; Ellenbogen, M.; Mazor, T.; Barak, D.

    1997-01-01

    A complete system for tracking, mapping, and performing a composition analysis of a radioactive plume and contaminated area was developed at the NRCN. The system includes two major units : An airborne unit for monitoring and a ground station for analyzing. The airborne unit is mounted on a helicopter and includes file following. Four radiation sensor, two 2'' x 2'' Nal (Tl) sensors horizontally separated by lead shield for mapping and spectroscopy, and two Geiger Mueller (GM) tubes as part of the safety system. A multichannel analyzer card is used for spectroscopy. A navigation system, based on GPS and a barometric altitude meter, is used to locate the plume or ground data. The telemetry system, consisting of a transceiver and a modem, transfers all the data in real time to the ground station. An industrial PC (Field Works) runs a dedicated C++ Windows application to manage the acquired data. An independent microprocessor based backup system includes a recorder, display, and key pad. The ground station is based on an industrial PC, a telemetry system, a color printer and a modem to communicate with automatic meteorology stations in the relevant area. A special software controls the ground station. Measurement results are analyzed in the ground station to estimate plume parameters including motion, location, size, velocity, and perform risk assessment. (authors)

  9. Alternative gravity theories

    International Nuclear Information System (INIS)

    Francaviglia, M.

    1990-01-01

    Although general relativity is a well-established discipline the theory deserves efforts aimed at producing alternative or more general frameworks for investigating the classical properties of gravity. These are either devoted to producing alternative viewpoints or interpretations of standard general relativity, or at constructing, discussing and proposing experimental tests for alternative descriptions of the dynamics of the gravitational field and its interaction (or unification) with external matter fields. Classical alternative theories of gravitation can roughly classified as follows; theories based on a still 4-dimensional picture, under the assumption that the dynamics of the gravitational field is more complicated than Einstein's and theories based on higher-dimensional pictures. This leads to supergravity and strings which are not included here. Theories based on higher-dimensional pictures on the assumption that space-time is replaced by a higher-dimensional manifold. Papers on these classifications are reviewed. (author)

  10. Airborne chemicals cause respiratory symptoms in individuals with contact allergy

    DEFF Research Database (Denmark)

    Elberling, J; Linneberg, A; Mosbech, H

    2005-01-01

    Exposure to fragrance chemicals causes various eye and airway symptoms. Individuals with perfume contact allergy report these symptoms more frequently than individuals with nickel allergy or no contact allergies. However, the associations between contact allergy and respiratory symptoms elicited...... by airborne chemicals other than perfumes are unclear. The study aimed to investigate the association between eye and airway symptoms elicited by airborne chemicals (other than perfumes) and contact allergy in a population-based sample. A questionnaire on respiratory symptoms was posted, in 2002, to 1189...... individuals who participated in 1997/1998 in a Danish population-based study of allergic diseases. Questions about eye and airway symptoms elicited by different airborne chemicals and airborne proteins were included in the questionnaire. Data from the questionnaire were compared with data on patch testing...

  11. Lower dimensional gravity

    International Nuclear Information System (INIS)

    Brown, J.D.

    1988-01-01

    This book addresses the subject of gravity theories in two and three spacetime dimensions. The prevailing philosophy is that lower dimensional models of gravity provide a useful arena for developing new ideas and insights, which are applicable to four dimensional gravity. The first chapter consists of a comprehensive introduction to both two and three dimensional gravity, including a discussion of their basic structures. In the second chapter, the asymptotic structure of three dimensional Einstein gravity with a negative cosmological constant is analyzed. The third chapter contains a treatment of the effects of matter sources in classical two dimensional gravity. The fourth chapter gives a complete analysis of particle pair creation by electric and gravitational fields in two dimensions, and the resulting effect on the cosmological constant

  12. Gravity interpretation via EULDPH

    International Nuclear Information System (INIS)

    Ebrahimzadeh Ardestani, V.

    2003-01-01

    Euler's homogeneity equation for determining the coordinates of the source body especially to estimate the depth (EULDPH) is discussed at this paper. This method is applied to synthetic and high-resolution real data such as gradiometric or microgravity data. Low-quality gravity data especially in the areas with a complex geology structure has rarely been used. The Bouguer gravity anomalies are computed from absolute gravity data after the required corrections. Bouguer anomaly is transferred to residual gravity anomaly. The gravity gradients are estimated from residual anomaly values. Bouguer anomaly is the gravity gradients, using EULDPH. The coordinates of the perturbing body will be determined. Two field examples one in the east of Tehran (Mard Abad) where we would like to determine the location of the anomaly (hydrocarbon) and another in the south-east of Iran close to the border with Afghanistan (Nosrat Abad) where we are exploring chromite are presented

  13. Anomalies and gravity

    International Nuclear Information System (INIS)

    Mielke, Eckehard W.

    2006-01-01

    Anomalies in Yang-Mills type gauge theories of gravity are reviewed. Particular attention is paid to the relation between the Dirac spin, the axial current j5 and the non-covariant gauge spin C. Using diagrammatic techniques, we show that only generalizations of the U(1)- Pontrjagin four-form F and F = dC arise in the chiral anomaly, even when coupled to gravity. Implications for Ashtekar's canonical approach to quantum gravity are discussed

  14. influence of gravity

    Directory of Open Access Journals (Sweden)

    Animesh Mukherjee

    1991-01-01

    Full Text Available Based upon Biot's [1965] theory of initial stresses of hydrostatic nature produced by the effect of gravity, a study is made of surface waves in higher order visco-elastic media under the influence of gravity. The equation for the wave velocity of Stonely waves in the presence of viscous and gravitational effects is obtained. This is followed by particular cases of surface waves including Rayleigh waves and Love waves in the presence of viscous and gravity effects. In all cases the wave-velocity equations are found to be in perfect agreement with the corresponding classical results when the effects of gravity and viscosity are neglected.

  15. Classical Weyl transverse gravity

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Ichiro [University of the Ryukyus, Department of Physics, Faculty of Science, Nishihara, Okinawa (Japan)

    2017-05-15

    We study various classical aspects of the Weyl transverse (WTDiff) gravity in a general space-time dimension. First of all, we clarify a classical equivalence among three kinds of gravitational theories, those are, the conformally invariant scalar tensor gravity, Einstein's general relativity and the WTDiff gravity via the gauge-fixing procedure. Secondly, we show that in the WTDiff gravity the cosmological constant is a mere integration constant as in unimodular gravity, but it does not receive any radiative corrections unlike the unimodular gravity. A key point in this proof is to construct a covariantly conserved energy-momentum tensor, which is achieved on the basis of this equivalence relation. Thirdly, we demonstrate that the Noether current for the Weyl transformation is identically vanishing, thereby implying that the Weyl symmetry existing in both the conformally invariant scalar tensor gravity and the WTDiff gravity is a ''fake'' symmetry. We find it possible to extend this proof to all matter fields, i.e. the Weyl-invariant scalar, vector and spinor fields. Fourthly, it is explicitly shown that in the WTDiff gravity the Schwarzschild black hole metric and a charged black hole one are classical solutions to the equations of motion only when they are expressed in the Cartesian coordinate system. Finally, we consider the Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology and provide some exact solutions. (orig.)

  16. Water Mapping Using Multispectral Airborne LIDAR Data

    Science.gov (United States)

    Yan, W. Y.; Shaker, A.; LaRocque, P. E.

    2018-04-01

    This study investigates the use of the world's first multispectral airborne LiDAR sensor, Optech Titan, manufactured by Teledyne Optech to serve the purpose of automatic land-water classification with a particular focus on near shore region and river environment. Although there exist recent studies utilizing airborne LiDAR data for shoreline detection and water surface mapping, the majority of them only perform experimental testing on clipped data subset or rely on data fusion with aerial/satellite image. In addition, most of the existing approaches require manual intervention or existing tidal/datum data for sample collection of training data. To tackle the drawbacks of previous approaches, we propose and develop an automatic data processing workflow for land-water classification using multispectral airborne LiDAR data. Depending on the nature of the study scene, two methods are proposed for automatic training data selection. The first method utilizes the elevation/intensity histogram fitted with Gaussian mixture model (GMM) to preliminarily split the land and water bodies. The second method mainly relies on the use of a newly developed scan line elevation intensity ratio (SLIER) to estimate the water surface data points. Regardless of the training methods being used, feature spaces can be constructed using the multispectral LiDAR intensity, elevation and other features derived from these parameters. The comprehensive workflow was tested with two datasets collected for different near shore region and river environment, where the overall accuracy yielded better than 96 %.

  17. Modeling for Airborne Contamination

    International Nuclear Information System (INIS)

    F.R. Faillace; Y. Yuan

    2000-01-01

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

  18. Bringing Artificial Gravity into the Classroom

    Science.gov (United States)

    Thompson, Grant; Aning, Isaac

    2018-01-01

    We recently conducted an experimental test of artificial gravity by placing various species of plants in centrifuges and analyzed the plants’ germination and growth. This research project incorporated several topics covered in undergraduate astronomy, biology, and physics courses. Given the interest of introductory astronomy students in artificial gravity and their pre-existing images of applications such as rotating spacecraft from pop culture, the results of the experiment may provide a gateway to discuss artificial gravity beyond teaching the traditional examples of Newton’s laws. We will discuss the experiment in detail and provide suggestions for how the experiment could be incorporated into your classroom.

  19. Lanczos–Lovelock models of gravity

    International Nuclear Information System (INIS)

    Padmanabhan, T.; Kothawala, D.

    2013-01-01

    Lanczos–Lovelock models of gravity represent a natural and elegant generalization of Einstein’s theory of gravity to higher dimensions. They are characterized by the fact that the field equations only contain up to second derivatives of the metric even though the action functional can be a quadratic or higher degree polynomial in the curvature tensor. Because these models share several key properties of Einstein’s theory they serve as a useful set of candidate models for testing the emergent paradigm for gravity. This review highlights several geometrical and thermodynamical aspects of Lanczos–Lovelock models which have attracted recent attention

  20. Gravity Probe B Inspection

    Science.gov (United States)

    2000-01-01

    The space vehicle Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. In this photograph, engineer Gary Reynolds is inspecting the inside of the probe neck during probe thermal repairs. GP-B is scheduled for launch in April 2004 and managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Leese, Gravity Probe B, Stanford University)

  1. airborne data analysis/monitor system

    Science.gov (United States)

    Stephison, D. B.

    1981-01-01

    An Airborne Data Analysis/Monitor System (ADAMS), a ROLM 1666 computer based system installed onboard test airplanes used during experimental testing is evaluated. In addition to the 1666 computer, the ADAMS hardware includes a DDC System 90 fixed head disk and a Miltape DD400 floppy disk. Boeing designed a DMA interface to the data acquisition system and an intelligent terminal to reduce system overhead and simplify operator commands. The ADAMS software includes RMX/RTOS and both ROLM FORTRAN and assembly language are used. The ADAMS provides real time displays that enable onboard test engineers to make rapid decisions about test conduct thus reducing the cost and time required to certify new model airplanes, and improved the quality of data derived from the test, leading to more rapid development of improvements resulting in quieter, safer, and more efficient airplanes. The availability of airborne data processing removes most of the weather and geographical restrictions imposed by telemetered flight test data systems. A data base is maintained to describe the airplane, the data acquisition system, the type of testing, and the conditions under which the test is performed.

  2. Airborne Cloud Computing Environment (ACCE)

    Science.gov (United States)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  3. Interior Alaska Bouguer Gravity Anomaly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 1 kilometer Complete Bouguer Anomaly gravity grid of interior Alaska. Only those grid cells within 10 kilometers of a gravity data point have gravity values....

  4. Consistency of orthodox gravity

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, S. [INFN, Frascati (Italy). Laboratori Nazionali di Frascati; Shiekh, A. [International Centre for Theoretical Physics, Trieste (Italy)

    1997-01-01

    A recent proposal for quantizing gravity is investigated for self consistency. The existence of a fixed-point all-order solution is found, corresponding to a consistent quantum gravity. A criterion to unify couplings is suggested, by invoking an application of their argument to more complex systems.

  5. Generalized pure Lovelock gravity

    Science.gov (United States)

    Concha, Patrick; Rodríguez, Evelyn

    2017-11-01

    We present a generalization of the n-dimensional (pure) Lovelock Gravity theory based on an enlarged Lorentz symmetry. In particular, we propose an alternative way to introduce a cosmological term. Interestingly, we show that the usual pure Lovelock gravity is recovered in a matter-free configuration. The five and six-dimensional cases are explicitly studied.

  6. Generalized pure Lovelock gravity

    Directory of Open Access Journals (Sweden)

    Patrick Concha

    2017-11-01

    Full Text Available We present a generalization of the n-dimensional (pure Lovelock Gravity theory based on an enlarged Lorentz symmetry. In particular, we propose an alternative way to introduce a cosmological term. Interestingly, we show that the usual pure Lovelock gravity is recovered in a matter-free configuration. The five and six-dimensional cases are explicitly studied.

  7. Weak lensing probes of modified gravity

    International Nuclear Information System (INIS)

    Schmidt, Fabian

    2008-01-01

    We study the effect of modifications to general relativity on large-scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the Dvali-Gabadadze-Porrati model, and tensor-vector-scalar theory. Weak lensing is sensitive to the growth of structure and the relation between matter and gravitational potentials, both of which will in general be affected by modified gravity. Restricting ourselves to linear scales, we compare the predictions for galaxy-shear and shear-shear correlations of each modified gravity cosmology to those of an effective dark energy cosmology with the same expansion history. In this way, the effects of modified gravity on the growth of perturbations are separated from the expansion history. We also propose a test which isolates the matter-potential relation from the growth factor and matter power spectrum. For all three modified gravity models, the predictions for galaxy and shear correlations will be discernible from those of dark energy with very high significance in future weak lensing surveys. Furthermore, each model predicts a measurably distinct scale dependence and redshift evolution of galaxy and shear correlations, which can be traced back to the physical foundations of each model. We show that the signal-to-noise for detecting signatures of modified gravity is much higher for weak lensing observables as compared to the integrated Sachs-Wolfe effect, measured via the galaxy-cosmic microwave background cross-correlation.

  8. Human Performance in Simulated Reduced Gravity Environments

    Science.gov (United States)

    Cowley, Matthew; Harvill, Lauren; Rajulu, Sudhakar

    2014-01-01

    NASA is currently designing a new space suit capable of working in deep space and on Mars. Designing a suit is very difficult and often requires trade-offs between performance, cost, mass, and system complexity. Our current understanding of human performance in reduced gravity in a planetary environment (the moon or Mars) is limited to lunar observations, studies from the Apollo program, and recent suit tests conducted at JSC using reduced gravity simulators. This study will look at our most recent reduced gravity simulations performed on the new Active Response Gravity Offload System (ARGOS) compared to the C-9 reduced gravity plane. Methods: Subjects ambulated in reduced gravity analogs to obtain a baseline for human performance. Subjects were tested in lunar gravity (1.6 m/sq s) and Earth gravity (9.8 m/sq s) in shirt-sleeves. Subjects ambulated over ground at prescribed speeds on the ARGOS, but ambulated at a self-selected speed on the C-9 due to time limitations. Subjects on the ARGOS were given over 3 minutes to acclimate to the different conditions before data was collected. Nine healthy subjects were tested in the ARGOS (6 males, 3 females, 79.5 +/- 15.7 kg), while six subjects were tested on the C-9 (6 males, 78.8 +/- 11.2 kg). Data was collected with an optical motion capture system (Vicon, Oxford, UK) and was analyzed using customized analysis scripts in BodyBuilder (Vicon, Oxford, UK) and MATLAB (MathWorks, Natick, MA, USA). Results: In all offloaded conditions, variation between subjects increased compared to 1-g. Kinematics in the ARGOS at lunar gravity resembled earth gravity ambulation more closely than the C-9 ambulation. Toe-off occurred 10% earlier in both reduced gravity environments compared to earth gravity, shortening the stance phase. Likewise, ankle, knee, and hip angles remained consistently flexed and had reduced peaks compared to earth gravity. Ground reaction forces in lunar gravity (normalized to Earth body weight) were 0.4 +/- 0.2 on

  9. ICESat-2 simulated data from airborne altimetery

    Science.gov (United States)

    Brunt, K. M.; Neumann, T.; Markus, T.; Brenner, A. C.; Barbieri, K.; Field, C.; Sirota, M.

    2010-12-01

    Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) is scheduled to launch in 2015 and will carry onboard the Advanced Topographic Laser Altimeter System (ATLAS), which represents a new approach to spaceborne determination of surface elevations. Specifically, the current ATLAS design is for a micropulse, multibeam, photon-counting laser altimeter with lower energy, a shorter pulse width, and a higher repetition rate relative to the Geoscience Laser Altimeter (GLAS), the instrument that was onboard ICESat. Given the new and untested technology associated with ATLAS, airborne altimetry data is necessary (1) to test the proposed ATLAS instrument geometry, (2) to validate instrument models, and (3) to assess the atmospheric effects on multibeam altimeters. We present an overview of the airborne instruments and datasets intended to address the ATLAS instrument concept, including data collected over Greenland (July 2009) using an airborne SBIR prototype 100 channel, photon-counting, terrain mapping altimeter, which addresses the first of these 3 scientific concerns. Additionally, we present the plan for further simulator data collection over vegetated and ice covered regions using Multiple Altimeter Beam Experimental Lidar (MABEL), intended to address the latter two scientific concerns. As the ICESAT-2 project is in the design phase, the particular configuration of the ATLAS instrument may change. However, we expect this work to be relevant as long as ATLAS pursues a photon-counting approach.

  10. Spatial variability in airborne pollen concentrations.

    Science.gov (United States)

    Raynor, G S; Ogden, E C; Hayes, J V

    1975-03-01

    Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.

  11. Airborne geophysical radon hazard mapping

    International Nuclear Information System (INIS)

    Walker, P.

    1993-01-01

    Shales containing uranium pose a radon health hazard even when covered by several meters of overburden. Such an alum shale in southern Norway has been mapped with a joint helicopter borne electromagnetic (HEM) and radiometric survey. Results are compared with ground spectrometer, radon emanometer and radon gas measurements in dwellings, and a model to predict radon gas concentrations from the airborne data is developed. Since the shale is conductive, combining the HEM data with the radiometric channel allows the shale to be mapped with greater reliability than if the radiometric channel were used alone. Radiometrically more active areas which do not pose a radon gas hazard can thus be separated from the shales which do. The ground follow-up work consisted of spectrometer and radon emanometer measurements over a uranium anomaly coinciding with a conductor. The correlation between the airborne uranium channel, the ground uranium channel and emanometry is extremely good, indicating that airborne geophysics can, in this case, be used to predict areas having a high radon potential. Contingency tables comparing both radon exhalation and concentration in dwellings with the airborne uranium data show a strong relationship exists between exhalation and the airborne data and while a relationship between concentration and the airborne data is present, but weaker

  12. How much gravity is needed to establish the perceptual upright?

    Science.gov (United States)

    Harris, Laurence R; Herpers, Rainer; Hofhammer, Thomas; Jenkin, Michael

    2014-01-01

    Might the gravity levels found on other planets and on the moon be sufficient to provide an adequate perception of upright for astronauts? Can the amount of gravity required be predicted from the physiological threshold for linear acceleration? The perception of upright is determined not only by gravity but also visual information when available and assumptions about the orientation of the body. Here, we used a human centrifuge to simulate gravity levels from zero to earth gravity along the long-axis of the body and measured observers' perception of upright using the Oriented Character Recognition Test (OCHART) with and without visual cues arranged to indicate a direction of gravity that differed from the body's long axis. This procedure allowed us to assess the relative contribution of the added gravity in determining the perceptual upright. Control experiments off the centrifuge allowed us to measure the relative contributions of normal gravity, vision, and body orientation for each participant. We found that the influence of 1 g in determining the perceptual upright did not depend on whether the acceleration was created by lying on the centrifuge or by normal gravity. The 50% threshold for centrifuge-simulated gravity's ability to influence the perceptual upright was at around 0.15 g, close to the level of moon gravity but much higher than the threshold for detecting linear acceleration along the long axis of the body. This observation may partially explain the instability of moonwalkers but is good news for future missions to Mars.

  13. Measurement analysis and quantum gravity

    International Nuclear Information System (INIS)

    Albers, Mark; Kiefer, Claus; Reginatto, Marcel

    2008-01-01

    We consider the question of whether consistency arguments based on measurement theory show that the gravitational field must be quantized. Motivated by the argument of Eppley and Hannah, we apply a DeWitt-type measurement analysis to a coupled system that consists of a gravitational wave interacting with a mass cube. We also review the arguments of Eppley and Hannah and of DeWitt, and investigate a second model in which a gravitational wave interacts with a quantized scalar field. We argue that one cannot conclude from the existing gedanken experiments that gravity has to be quantized. Despite the many physical arguments which speak in favor of a quantum theory of gravity, it appears that the justification for such a theory must be based on empirical tests and does not follow from logical arguments alone.

  14. Gravity in 2+ 1 dimensions

    International Nuclear Information System (INIS)

    Gerbert, P.S.

    1989-01-01

    A review of 2+1-dimensional gravity, and recent results concerning the quantum scattering of Klein-Gordon and Dirac test particles in background of point sources with and without spin are presented. The classical theory and general remarks of 2+1 dimensional gravity are reviewed. The space-time in presence of point sources is described. The classical scattering and applications to (Spinning) cosmic strings are discussed. The quantum theory is considered analysing the two body scattering problem. The scattering of spinless particles is discussed including spin-effects. Some classifying remarks about three-dimensional analogue of hte Weyl tensor and Chern-Simons theories of gravitation are also presented. (M.C.K.)

  15. Characterization of airborne bacteria at an underground subway station.

    Science.gov (United States)

    Dybwad, Marius; Granum, Per Einar; Bruheim, Per; Blatny, Janet Martha

    2012-03-01

    The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization-time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers.

  16. Factors contributing to airborne particle dispersal in the operating room.

    Science.gov (United States)

    Noguchi, Chieko; Koseki, Hironobu; Horiuchi, Hidehiko; Yonekura, Akihiko; Tomita, Masato; Higuchi, Takashi; Sunagawa, Shinya; Osaki, Makoto

    2017-07-06

    Surgical-site infections due to intraoperative contamination are chiefly ascribable to airborne particles carrying microorganisms. The purpose of this study is to identify the actions that increase the number of airborne particles in the operating room. Two surgeons and two surgical nurses performed three patterns of physical movements to mimic intraoperative actions, such as preparing the instrument table, gowning and donning/doffing gloves, and preparing for total knee arthroplasty. The generation and behavior of airborne particles were filmed using a fine particle visualization system, and the number of airborne particles in 2.83 m 3 of air was counted using a laser particle counter. Each action was repeated five times, and the particle measurements were evaluated through one-way analysis of variance multiple comparison tests followed by Tukey-Kramer and Bonferroni-Dunn multiple comparison tests for post hoc analysis. Statistical significance was defined as a P value ≤ .01. A large number of airborne particles were observed while unfolding the surgical gown, removing gloves, and putting the arms through the sleeves of the gown. Although numerous airborne particles were observed while applying the stockinet and putting on large drapes for preparation of total knee arthroplasty, fewer particles (0.3-2.0 μm in size) were detected at the level of the operating table under laminar airflow compared to actions performed in a non-ventilated preoperative room (P airborne particles near a sterile area and that laminar airflow has the potential to reduce the incidence of bacterial contamination.

  17. Characterization of Airborne Bacteria at an Underground Subway Station

    Science.gov (United States)

    Dybwad, Marius; Granum, Per Einar; Bruheim, Per

    2012-01-01

    The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization–time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers. PMID:22247150

  18. Karoo airborne geophysical survey

    International Nuclear Information System (INIS)

    Cole, D.J.; Stettler, E.H.

    1984-01-01

    Thirty four uranium anomalies were selected for ground follow-up from the analogue spectrometer records of Block 4 of the Karoo Airborne Geophysical Survey. The anomalies were plotted on 1:50 000 scale topographic maps and to 1:250 000 scale maps which are included in this report. The anomaly co-ordinates are tabulated together with the farms on which they occur. Results of the ground follow-up of the aerial anomalies are described. Twenty two anomalies are related to uranium mineralisation of which seventeen occur over baked mudstone adjacent to a dolerite intrusion. Five are located over fluvial channel sandstone of the Beaufort Group and subsurface mineralised sandstone may be present. The other twelve anomalies are spurious. Of the anomalies located over baked mudstone, fifteen emanate from ferruginous mudstone of the Whitehill Formation west of longitude 21 degrees 15 minutes. One of the two remaining anomalies over baked mudstone occurs over the Prince Albert Formation and the other anomaly is over baked mudstone and calcareous nodules of the Beaufort Group. The general low uranium values (less than 355 ppm eU3O8) render the occurrences uneconomic

  19. Lattice gravity and strings

    International Nuclear Information System (INIS)

    Jevicki, A.; Ninomiya, M.

    1985-01-01

    We are concerned with applications of the simplicial discretization method (Regge calculus) to two-dimensional quantum gravity with emphasis on the physically relevant string model. Beginning with the discretization of gravity and matter we exhibit a discrete version of the conformal trace anomaly. Proceeding to the string problem we show how the direct approach of (finite difference) discretization based on Nambu action corresponds to unsatisfactory treatment of gravitational degrees. Based on the Regge approach we then propose a discretization corresponding to the Polyakov string. In this context we are led to a natural geometric version of the associated Liouville model and two-dimensional gravity. (orig.)

  20. Scaling in quantum gravity

    Directory of Open Access Journals (Sweden)

    J. Ambjørn

    1995-07-01

    Full Text Available The 2-point function is the natural object in quantum gravity for extracting critical behavior: The exponential falloff of the 2-point function with geodesic distance determines the fractal dimension dH of space-time. The integral of the 2-point function determines the entropy exponent γ, i.e. the fractal structure related to baby universes, while the short distance behavior of the 2-point function connects γ and dH by a quantum gravity version of Fisher's scaling relation. We verify this behavior in the case of 2d gravity by explicit calculation.

  1. Towards unification of terrestrial gravity data sets in Estonia

    Directory of Open Access Journals (Sweden)

    Ellmann, Artu

    2009-12-01

    Full Text Available Gravity data in Estonia have been collected by different institutions over many decades. This study assesses the suitability of available gravity data for ensuring a 1 cm geoid modelling accuracy over Estonia and in the Baltic Sea region in general. The main focus of this study is on the determination and elimination of discrepancies between three nationwide datasets. It was detected that one tested historic gravity dataset contained inadmissible systematic biases with respect to other tested datasets. Possible ways of gravity data improvement are discussed. More specifically, new field observation campaigns and aspects of using their outcomes in subsequent regional geoid modelling are suggested.

  2. Airborne soil particulates as vehicles for Salmonella contamination of tomatoes.

    Science.gov (United States)

    Kumar, Govindaraj Dev; Williams, Robert C; Al Qublan, Hamzeh M; Sriranganathan, Nammalwar; Boyer, Renee R; Eifert, Joseph D

    2017-02-21

    The presence of dust is ubiquitous in the produce growing environment and its deposition on edible crops could occur. The potential of wind-distributed soil particulate to serve as a vehicle for S. Newport transfer to tomato blossoms and consequently, to fruits, was explored. Blossoms were challenged with previously autoclaved soil containing S. Newport (9.39log CFU/g) by brushing and airborne transfer. One hundred percent of blossoms brushed with S. Newport-contaminated soil tested positive for presence of the pathogen one week after contact (PCompressed air was used to simulate wind currents and direct soil particulates towards blossoms. Airborne soil particulates resulted in contamination of 29% of the blossoms with S. Newport one week after contact. Biophotonic imaging of blossoms post-contact with bioluminescent S. Newport-contaminated airborne soil particulates revealed transfer of the pathogen on petal, stamen and pedicel structures. Both fruits and calyxes that developed from blossoms contaminated with airborne soil particulates were positive for presence of S. Newport in both fruit (66.6%) and calyx (77.7%). Presence of S. Newport in surface-sterilized fruit and calyx tissue tested indicated internalization of the pathogen. These results show that airborne soil particulates could serve as a vehicle for Salmonella. Hence, Salmonella contaminated dust and soil particulate dispersion could contribute to pathogen contamination of fruit, indicating an omnipresent yet relatively unexplored contamination route. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Gravity Data for Egypt

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (71 records) were gathered by various governmental organizations (and academia) using a variety of methods. This data base was received in...

  4. New massive gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Hohm, Olaf; Townsend, Paul K.

    2012-01-01

    We present a brief review of New Massive Gravity, which is a unitary theory of massive gravitons in three dimensions obtained by considering a particular combination of the Einstein-Hilbert and curvature squared terms.

  5. DMA Antarctic Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (65,164 records) were gathered by various governmental organizations (and academia) using a variety of methods. The data base was received...

  6. Gravity Data for Minnesota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (55,907 records) were gathered by various governmental organizations (and academia) using a variety of methods. This data base was received...

  7. Stability in designer gravity

    International Nuclear Information System (INIS)

    Hertog, Thomas; Hollands, Stefan

    2005-01-01

    We study the stability of designer gravity theories, in which one considers gravity coupled to a tachyonic scalar with anti-de Sitter (AdS) boundary conditions defined by a smooth function W. We construct Hamiltonian generators of the asymptotic symmetries using the covariant phase space method of Wald et al and find that they differ from the spinor charges except when W = 0. The positivity of the spinor charge is used to establish a lower bound on the conserved energy of any solution that satisfies boundary conditions for which W has a global minimum. A large class of designer gravity theories therefore have a stable ground state, which the AdS/CFT correspondence indicates should be the lowest energy soliton. We make progress towards proving this by showing that minimum energy solutions are static. The generalization of our results to designer gravity theories in higher dimensions involving several tachyonic scalars is discussed

  8. Carroll versus Galilei gravity

    Energy Technology Data Exchange (ETDEWEB)

    Bergshoeff, Eric [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Gomis, Joaquim [Departament de Física Cuàntica i Astrofísica and Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, E-08028 Barcelona (Spain); Rollier, Blaise [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Rosseel, Jan [Faculty of Physics, University of Vienna,Boltzmanngasse 5, A-1090 Vienna (Austria); Veldhuis, Tonnis ter [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands)

    2017-03-30

    We consider two distinct limits of General Relativity that in contrast to the standard non-relativistic limit can be taken at the level of the Einstein-Hilbert action instead of the equations of motion. One is a non-relativistic limit and leads to a so-called Galilei gravity theory, the other is an ultra-relativistic limit yielding a so-called Carroll gravity theory. We present both gravity theories in a first-order formalism and show that in both cases the equations of motion (i) lead to constraints on the geometry and (ii) are not sufficient to solve for all of the components of the connection fields in terms of the other fields. Using a second-order formalism we show that these independent components serve as Lagrange multipliers for the geometric constraints we found earlier. We point out a few noteworthy differences between Carroll and Galilei gravity and give some examples of matter couplings.

  9. Discrete quantum gravity

    International Nuclear Information System (INIS)

    Williams, Ruth M

    2006-01-01

    A review is given of a number of approaches to discrete quantum gravity, with a restriction to those likely to be relevant in four dimensions. This paper is dedicated to Rafael Sorkin on the occasion of his sixtieth birthday

  10. Gravity Probe B Encapsulated

    Science.gov (United States)

    2004-01-01

    In this photo, the Gravity Probe B (GP-B) space vehicle is being encapsulated atop the Delta II launch vehicle. The GP-B is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation).

  11. The earth's shape and gravity

    CERN Document Server

    Garland, G D; Wilson, J T

    2013-01-01

    The Earth's Shape and Gravity focuses on the progress of the use of geophysical methods in investigating the interior of the earth and its shape. The publication first offers information on gravity, geophysics, geodesy, and geology and gravity measurements. Discussions focus on gravity measurements and reductions, potential and equipotential surfaces, absolute and relative measurements, and gravity networks. The text then elaborates on the shape of the sea-level surface and reduction of gravity observations. The text takes a look at gravity anomalies and structures in the earth's crust; interp

  12. Streaming gravity mode instability

    International Nuclear Information System (INIS)

    Wang Shui.

    1989-05-01

    In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

  13. On higher derivative gravity

    International Nuclear Information System (INIS)

    Accioly, A.J.

    1987-01-01

    A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the framework of this higher-derivative gravity. This very peculiar and rare result is the first known vcuum solution of the fourth-order gravity theory that is not a solution of the corresponding Einstein's equations.(Author) [pt

  14. What Is Gravity?

    Science.gov (United States)

    Nelson, George

    2004-01-01

    Gravity is the name given to the phenomenon that any two masses, like you and the Earth, attract each other. One pulls on the Earth and the Earth pulls on one the same amount. And one does not have to be touching. Gravity acts over vast distances, like the 150 million kilometers (93 million miles) between the Earth and the Sun or the billions of…

  15. Automated borehole gravity meter system

    International Nuclear Information System (INIS)

    Lautzenhiser, Th.V.; Wirtz, J.D.

    1984-01-01

    An automated borehole gravity meter system for measuring gravity within a wellbore. The gravity meter includes leveling devices for leveling the borehole gravity meter, displacement devices for applying forces to a gravity sensing device within the gravity meter to bring the gravity sensing device to a predetermined or null position. Electronic sensing and control devices are provided for (i) activating the displacement devices, (ii) sensing the forces applied to the gravity sensing device, (iii) electronically converting the values of the forces into a representation of the gravity at the location in the wellbore, and (iv) outputting such representation. The system further includes electronic control devices with the capability of correcting the representation of gravity for tidal effects, as well as, calculating and outputting the formation bulk density and/or porosity

  16. Extrasolar planets as a probe of modified gravity

    OpenAIRE

    Vargas dos Santos, Marcelo; Mota, David F.

    2017-01-01

    We propose a new method to test modified gravity theories, taking advantage of the available data on extrasolar planets. We computed the deviations from the Kepler third law and use that to constrain gravity theories beyond General Relativity. We investigate gravity models which incorporate three screening mechanisms: the Chameleon, the Symmetron and the Vainshtein. We find that data from exoplanets orbits are very sensitive to the screening mechanisms putting strong constraints in the parame...

  17. Gravity Before Einstein and Schwinger Before Gravity

    Science.gov (United States)

    Trimble, Virginia L.

    2012-05-01

    Julian Schwinger was a child prodigy, and Albert Einstein distinctly not; Schwinger had something like 73 graduate students, and Einstein very few. But both thought gravity was important. They were not, of course, the first, nor is the disagreement on how one should think about gravity that is being highlighted here the first such dispute. The talk will explore, first, several of the earlier dichotomies: was gravity capable of action at a distance (Newton), or was a transmitting ether required (many others). Did it act on everything or only on solids (an odd idea of the Herschels that fed into their ideas of solar structure and sunspots)? Did gravitational information require time for its transmission? Is the exponent of r precisely 2, or 2 plus a smidgeon (a suggestion by Simon Newcomb among others)? And so forth. Second, I will try to say something about Scwinger's lesser known early work and how it might have prefigured his "source theory," beginning with "On the Interaction of Several Electrons (the unpublished, 1934 "zeroth paper," whose title somewhat reminds one of "On the Dynamics of an Asteroid," through his days at Berkeley with Oppenheimer, Gerjuoy, and others, to his application of ideas from nuclear physics to radar and of radar engineering techniques to problems in nuclear physics. And folks who think good jobs are difficult to come by now might want to contemplate the couple of years Schwinger spent teaching elementary physics at Purdue before moving on to the MIT Rad Lab for war work.

  18. Extended Theories of Gravity

    International Nuclear Information System (INIS)

    Capozziello, Salvatore; De Laurentis, Mariafelicia

    2011-01-01

    Extended Theories of Gravity can be considered as a new paradigm to cure shortcomings of General Relativity at infrared and ultraviolet scales. They are an approach that, by preserving the undoubtedly positive results of Einstein’s theory, is aimed to address conceptual and experimental problems recently emerged in astrophysics, cosmology and High Energy Physics. In particular, the goal is to encompass, in a self-consistent scheme, problems like inflation, dark energy, dark matter, large scale structure and, first of all, to give at least an effective description of Quantum Gravity. We review the basic principles that any gravitational theory has to follow. The geometrical interpretation is discussed in a broad perspective in order to highlight the basic assumptions of General Relativity and its possible extensions in the general framework of gauge theories. Principles of such modifications are presented, focusing on specific classes of theories like f(R)-gravity and scalar–tensor gravity in the metric and Palatini approaches. The special role of torsion is also discussed. The conceptual features of these theories are fully explored and attention is paid to the issues of dynamical and conformal equivalence between them considering also the initial value problem. A number of viability criteria are presented considering the post-Newtonian and the post-Minkowskian limits. In particular, we discuss the problems of neutrino oscillations and gravitational waves in extended gravity. Finally, future perspectives of extended gravity are considered with possibility to go beyond a trial and error approach.

  19. Estimating Gravity Biases with Wavelets in Support of a 1-cm Accurate Geoid Model

    Science.gov (United States)

    Ahlgren, K.; Li, X.

    2017-12-01

    Systematic errors that reside in surface gravity datasets are one of the major hurdles in constructing a high-accuracy geoid model at high resolutions. The National Oceanic and Atmospheric Administration's (NOAA) National Geodetic Survey (NGS) has an extensive historical surface gravity dataset consisting of approximately 10 million gravity points that are known to have systematic biases at the mGal level (Saleh et al. 2013). As most relevant metadata is absent, estimating and removing these errors to be consistent with a global geopotential model and airborne data in the corresponding wavelength is quite a difficult endeavor. However, this is crucial to support a 1-cm accurate geoid model for the United States. With recently available independent gravity information from GRACE/GOCE and airborne gravity from the NGS Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project, several different methods of bias estimation are investigated which utilize radial basis functions and wavelet decomposition. We estimate a surface gravity value by incorporating a satellite gravity model, airborne gravity data, and forward-modeled topography at wavelet levels according to each dataset's spatial wavelength. Considering the estimated gravity values over an entire gravity survey, an estimate of the bias and/or correction for the entire survey can be found and applied. In order to assess the accuracy of each bias estimation method, two techniques are used. First, each bias estimation method is used to predict the bias for two high-quality (unbiased and high accuracy) geoid slope validation surveys (GSVS) (Smith et al. 2013 & Wang et al. 2017). Since these surveys are unbiased, the various bias estimation methods should reflect that and provide an absolute accuracy metric for each of the bias estimation methods. Secondly, the corrected gravity datasets from each of the bias estimation methods are used to build a geoid model. The accuracy of each geoid model

  20. A comment on ''A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model'', by I. Ciufolini et al

    Energy Technology Data Exchange (ETDEWEB)

    Iorio, Lorenzo [Ministero dell' Istruzione Univ. della Ricerca (M.I.U.R.), Bari (Italy)

    2017-02-15

    Recently, Ciufolini et al. reported on a test of the general relativistic gravitomagnetic Lense-Thirring effect by analyzing about 3.5 years of laser ranging data to the LAGEOS, LAGEOS II, LARES geodetic satellites orbiting the Earth. By using the GRACE-based GGM05S Earth's global gravity model and a linear combination of the nodes Ω of the three satellites designed to remove the impact of errors in the first two even zonal harmonic coefficients J{sub 2}, J{sub 4} of the multipolar expansion of the Newtonian part of the Earth's gravitational potential, they claimed an overall accuracy of 5% for the Lense-Thirring caused node motion. We show that the scatter in the nominal values of the uncancelled even zonals of degree l = 6, 8, 10 from some of the most recent global gravity models does not yet allow to reach unambiguously and univocally the expected ∼1% level, being large up to

  1. Airborne geoid mapping of land and sea areas of East Malaysia

    Science.gov (United States)

    Jamil, H.; Kadir, M.; Forsberg, R.; Olesen, A.; Isa, M. N.; Rasidi, S.; Mohamed, A.; Chihat, Z.; Nielsen, E.; Majid, F.; Talib, K.; Aman, S.

    2017-02-01

    This paper describes the development of a new geoid-based vertical datum from airborne gravity data, by the Department of Survey and Mapping Malaysia, on land and in the South China Sea out of the coast of East Malaysia region, covering an area of about 610,000 square kilometres. More than 107,000 km flight line of airborne gravity data over land and marine areas of East Malaysia has been combined to provide a seamless land-to-sea gravity field coverage; with an estimated accuracy of better than 2.0 mGal. The iMAR-IMU processed gravity anomaly data has been used during a 2014-2016 airborne survey to extend a composite gravity solution across a number of minor gaps on selected lines, using a draping technique. The geoid computations were all done with the GRAVSOFT suite of programs from DTU-Space. EGM2008 augmented with GOCE spherical harmonic model has been used to spherical harmonic degree N = 720. The gravimetric geoid first was tied at one tide-gauge (in Kota Kinabalu, KK2019) to produce a fitted geoid, my_geoid2017_fit_kk. The fitted geoid was offset from the gravimetric geoid by +0.852 m, based on the comparison at the tide-gauge benchmark KK2019. Consequently, orthometric height at the six other tide gauge stations was computed from HGPS Lev = hGPS - Nmy_geoid2017_.t_kk. Comparison of the conventional (HLev) and GPS-levelling heights (HGPS Lev) at the six tide gauge locations indicate RMS height difference of 2.6 cm. The final gravimetric geoidwas fitted to the seven tide gauge stations and is known as my_geoid2017_fit_east. The accuracy of the gravimetric geoid is estimated to be better than 5 cm across most of East Malaysia land and marine areas

  2. Detection Range of Airborne Magnetometers in Magnetic Anomaly Detection

    Directory of Open Access Journals (Sweden)

    Chengjing Li

    2015-11-01

    Full Text Available Airborne magnetometers are utilized for the small-range search, precise positioning, and identification of the ferromagnetic properties of underwater targets. As an important performance parameter of sensors, the detection range of airborne magnetometers is commonly set as a fixed value in references regardless of the influences of environment noise, target magnetic properties, and platform features in a classical model to detect airborne magnetic anomalies. As a consequence, deviation in detection ability analysis is observed. In this study, a novel detection range model is proposed on the basis of classic detection range models of airborne magnetometers. In this model, probability distribution is applied, and the magnetic properties of targets and the environment noise properties of a moving submarine are considered. The detection range model is also constructed by considering the distribution of the moving submarine during detection. A cell-averaging greatest-of-constant false alarm rate test method is also used to calculate the detection range of the model at a desired false alarm rate. The detection range model is then used to establish typical submarine search probabilistic models. Results show that the model can be used to evaluate not only the effects of ambient magnetic noise but also the moving and geomagnetic features of the target and airborne detection platform. The model can also be utilized to display the actual operating range of sensor systems.

  3. Airborne Particulate Matter Induces Nonallergic Eosinophilic Sinonasal Inflammation in Mice.

    Science.gov (United States)

    Ramanathan, Murugappan; London, Nyall R; Tharakan, Anuj; Surya, Nitya; Sussan, Thomas E; Rao, Xiaoquan; Lin, Sandra Y; Toskala, Elina; Rajagopalan, Sanjay; Biswal, Shyam

    2017-07-01

    Exposure to airborne particulate matter (PM) has been linked to aggravation of respiratory symptoms, increased risk of cardiovascular disease, and all-cause mortality. Although the health effects of PM on the lower pulmonary airway have been extensively studied, little is known regarding the impact of chronic PM exposure on the upper sinonasal airway. We sought to test the impact of chronic airborne PM exposure on the upper respiratory system in vivo. Mice were subjected, by inhalation, to concentrated fine (2.5 μm) PM 6 h/d, 5 d/wk, for 16 weeks. Mean airborne fine PM concentration was 60.92 μm/m 3 , a concentration of fine PM lower than that reported in some major global cities. Mice were then killed and analyzed for evidence of inflammation and barrier breakdown compared with control mice. Evidence of the destructive effects of chronic airborne PM on sinonasal health in vivo, including proinflammatory cytokine release, and macrophage and neutrophil inflammatory cell accumulation was observed. A significant increase in epithelial barrier dysfunction was observed, as assessed by serum albumin accumulation in nasal airway lavage fluid, as well as decreased expression of adhesion molecules, including claudin-1 and epithelial cadherin. A significant increase in eosinophilic inflammation, including increased IL-13, eotaxin-1, and eosinophil accumulation, was also observed. Collectively, although largely observational, these studies demonstrate the destructive effects of chronic airborne PM exposure on the sinonasal airway barrier disruption and nonallergic eosinophilic inflammation in mice.

  4. On regulation of radioactive airborne discharge

    International Nuclear Information System (INIS)

    Stroganov, A.A.; Kuryndin, A.V.; Shapovalov, A.S.; Orlov, M.Yu.

    2013-01-01

    Authors present the Russian regulatory basis of radioactive airborne discharges which was updated after enactment of the Methodology for airborne discharge limits development. Criteria for establishing of airborne discharge limits, scope and other features of methodology are also considered in the article [ru

  5. Airborne Optical Systems Test Bed (AOSTB)

    Science.gov (United States)

    2016-07-01

    radar sensor to perform data collection. It has enabled low-cost data fusion collections, which involve simultaneously imaging a scene with multiple...successfully completed, and the next milestones involve continuing to market this important capability of The Laboratory, and supporting the various...in how to invent, innovate, and implement engineering projects from concept to market success, and the rest of the Gordon Institute cadre for their

  6. Airborne Data Link Operational Evaluation Test Plan

    Science.gov (United States)

    1993-08-01

    This plan describes an end-to-end study of operational concepts and procedures associated with the introduction of electronic data communications between flight crews and air traffic controllers. Full performance controllers from : terminal facilitie...

  7. Gravity and Extreme Magnetism SMEX

    Science.gov (United States)

    2012-01-01

    The Gravity and Extreme Magnetism SMEX mission will be the first mission to catalogue the X-ray polarisation of many astrophysical objects including black-holes and pulsars. This first of its kind mission is enabled by the novel use of a time projection chamber as an X-ray polarimeter. The detector has been developed over the last 5 years, with the current effort charged toward a demonstration of it's technical readiness to be at level 6 prior to the preliminary design review. This talk will describe the design GEMS polarimeter and the results to date from the engineering test unit.

  8. Gravity settling of precipitated magnetite and ferric floc

    International Nuclear Information System (INIS)

    Holt, N.S.; Loft, P.R.

    1983-06-01

    A comparison is presented of the gravity settling performance of ferric floc and magnetite, both in batch settling tests, and on a continuous gravity settler. The precipitation of magnetite from solution on a continuous basis was also demonstrated, and the process was shown not to be significantly affected by the presence of a wide range of chemical species. (U.K.)

  9. The Effect of Divided Attention on Inhibiting the Gravity Error

    Science.gov (United States)

    Hood, Bruce M.; Wilson, Alice; Dyson, Sally

    2006-01-01

    Children who could overcome the gravity error on Hood's (1995) tubes task were tested in a condition where they had to monitor two falling balls. This condition significantly impaired search performance with the majority of mistakes being gravity errors. In a second experiment, the effect of monitoring two balls was compared in the tubes task and…

  10. Gravity Probe B Assembled

    Science.gov (United States)

    2000-01-01

    In this photo, the Gravity Probe B (GP-B) space vehicle is being assembled at the Sunnyvale, California location of the Lockheed Martin Corporation. The GP-B is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation).

  11. Quantum Gravity Experiments

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2015-10-01

    Full Text Available A new quantum gravity experiment is reported with the data confirming the generali- sation of the Schrödinger equation to include the interaction of the wave function with dynamical space. Dynamical space turbulence, via this interaction process, raises and lowers the energy of the electron wave function, which is detected by observing conse- quent variations in the electron quantum barrier tunnelling rate in reverse-biased Zener diodes. This process has previously been reported and enabled the measurement of the speed of the dynamical space flow, which is consistent with numerous other detection experiments. The interaction process is dependent on the angle between the dynamical space flow velocity and the direction of the electron flow in the diode, and this depen- dence is experimentally demonstrated. This interaction process explains gravity as an emergent quantum process, so unifying quantum phenomena and gravity. Gravitational waves are easily detected.

  12. Gravity and strings

    CERN Document Server

    Ortín, Tomás

    2015-01-01

    Self-contained and comprehensive, this definitive new edition of Gravity and Strings is a unique resource for graduate students and researchers in theoretical physics. From basic differential geometry through to the construction and study of black-hole and black-brane solutions in quantum gravity - via all the intermediate stages - this book provides a complete overview of the intersection of gravity, supergravity, and superstrings. Now fully revised, this second edition covers an extensive array of topics, including new material on non-linear electric-magnetic duality, the electric-tensor formalism, matter-coupled supergravity, supersymmetric solutions, the geometries of scalar manifolds appearing in 4- and 5-dimensional supergravities, and much more. Covering reviews of important solutions and numerous solution-generating techniques, and accompanied by an exhaustive index and bibliography, this is an exceptional reference work.

  13. Solitons in Newtonian gravity

    International Nuclear Information System (INIS)

    Goetz, G.

    1988-01-01

    It is shown that the plane-wave solutions for the equations governing the motion of a self-gravitating isothermal fluid in Newtonian hydrodynamics are generated by a sine-Gordon equation which is solvable by an 'inverse scattering' transformation. A transformation procedure is outlined by means of which one can construct solutions of the gravity system out of a pair of solutions of the sine-Gordon equation, which are interrelated via an auto-Baecklund transformation. In general the solutions to the gravity system are obtained in a parametric representation in terms of characteristic coordinates. All solutions of the gravity system generated by the one-and two-soliton solutions of the sine-Gordon equation can be constructed explicitly. These might provide models for the evolution of flat structures as they are predicted to arise in the process of galaxy formation. (author)

  14. Stochastic quantum gravity

    International Nuclear Information System (INIS)

    Rumpf, H.

    1987-01-01

    We begin with a naive application of the Parisi-Wu scheme to linearized gravity. This will lead into trouble as one peculiarity of the full theory, the indefiniteness of the Euclidean action, shows up already at this level. After discussing some proposals to overcome this problem, Minkowski space stochastic quantization will be introduced. This will still not result in an acceptable quantum theory of linearized gravity, as the Feynman propagator turns out to be non-causal. This defect will be remedied only after a careful analysis of general covariance in stochastic quantization has been performed. The analysis requires the notion of a metric on the manifold of metrics, and a natural candidate for this is singled out. With this a consistent stochastic quantization of Einstein gravity becomes possible. It is even possible, at least perturbatively, to return to the Euclidean regime. 25 refs. (Author)

  15. No slip gravity

    Science.gov (United States)

    Linder, Eric V.

    2018-03-01

    A subclass of the Horndeski modified gravity theory we call No Slip Gravity has particularly interesting properties: 1) a speed of gravitational wave propagation equal to the speed of light, 2) equality between the effective gravitational coupling strengths to matter and light, Gmatter and Glight, hence no slip between the metric potentials, yet difference from Newton's constant, and 3) suppressed growth to give better agreement with galaxy clustering observations. We explore the characteristics and implications of this theory, and project observational constraints. We also give a simple expression for the ratio of the gravitational wave standard siren distance to the photon standard candle distance, in this theory and others, and enable a direct comparison of modified gravity in structure growth and in gravitational waves, an important crosscheck.

  16. The quantization of gravity

    CERN Document Server

    Gerhardt, Claus

    2018-01-01

    A unified quantum theory incorporating the four fundamental forces of nature is one of the major open problems in physics. The Standard Model combines electro-magnetism, the strong force and the weak force, but ignores gravity. The quantization of gravity is therefore a necessary first step to achieve a unified quantum theory. In this monograph a canonical quantization of gravity has been achieved by quantizing a geometric evolution equation resulting in a gravitational wave equation in a globally hyperbolic spacetime. Applying the technique of separation of variables we obtain eigenvalue problems for temporal and spatial self-adjoint operators where the temporal operator has a pure point spectrum with eigenvalues $\\lambda_i$ and related eigenfunctions, while, for the spatial operator, it is possible to find corresponding eigendistributions for each of the eigenvalues $\\lambda_i$, if the Cauchy hypersurface is asymptotically Euclidean or if the quantized spacetime is a black hole with a negative cosmological ...

  17. Potential airborne release from soil-working operations in a contaminated area

    International Nuclear Information System (INIS)

    Sutter, S.L.

    1980-08-01

    Experiments were performed to provide an indication of how much material could be made airborne during soil-working operations in a contaminated area. Approximately 50 kg of contaminated soil were collected, dried, and mixed, and particle size distribution and 137 Cs content were characterized. In four experiments performed in a 2 ft x 2 ft wind tunnel at the Radioactive Aerosol Release Test Facility, soil was pumped into an airstream moving at 3.2, 10.4, 15.2, and 20 mph. These experiments were designed to maximize airborne releases by fluidizing the soil as it was pumped into the wind tunnel. Thus the airborne releases should represent upper limit values for soil-working operations. Airborne concentration and particle size samples were collected and all of the material deposited downstream was collected to calculate a mass balance. The fraction airborne was calculated using these measurements

  18. Surfing surface gravity waves

    Science.gov (United States)

    Pizzo, Nick

    2017-11-01

    A simple criterion for water particles to surf an underlying surface gravity wave is presented. It is found that particles travelling near the phase speed of the wave, in a geometrically confined region on the forward face of the crest, increase in speed. The criterion is derived using the equation of John (Commun. Pure Appl. Maths, vol. 6, 1953, pp. 497-503) for the motion of a zero-stress free surface under the action of gravity. As an example, a breaking water wave is theoretically and numerically examined. Implications for upper-ocean processes, for both shallow- and deep-water waves, are discussed.

  19. Towards a quantum gravity

    International Nuclear Information System (INIS)

    Romney, B.; Barrau, A.; Vidotto, F.; Le Meur, H.; Noui, K.

    2011-01-01

    The loop quantum gravity is the only theory that proposes a quantum description of space-time and therefore of gravitation. This theory predicts that space is not infinitely divisible but that is has a granular structure at the Planck scale (10 -35 m). Another feature of loop quantum gravity is that it gets rid of the Big-Bang singularity: our expanding universe may come from the bouncing of a previous contracting universe, in this theory the Big-Bang is replaced with a big bounce. The loop quantum theory predicts also the huge number of quantum states that accounts for the entropy of large black holes. (A.C.)

  20. Terrestrial gravity data analysis for interim gravity model improvement

    Science.gov (United States)

    1987-01-01

    This is the first status report for the Interim Gravity Model research effort that was started on June 30, 1986. The basic theme of this study is to develop appropriate models and adjustment procedures for estimating potential coefficients from terrestrial gravity data. The plan is to use the latest gravity data sets to produce coefficient estimates as well as to provide normal equations to NASA for use in the TOPEX/POSEIDON gravity field modeling program.

  1. From Discrete Gravity Survey Data to a High-resolution Gravity Field Representation in the Nordic-Baltic Region

    DEFF Research Database (Denmark)

    Märdla, Silja; Ågren, Jonas; Strykowski, Gabriel

    2017-01-01

    The deduction of a regularly spaced gravity anomaly grid from scattered survey data is studied, addressing mainly two aspects: reduction of gravity to anomalies and subsequent interpolation by various methods. The problem is illustrated in a heterogeneous study area and contrasting test areas inc...

  2. Non-allergic cutaneous reactions in airborne chemical sensitivity--a population based study

    DEFF Research Database (Denmark)

    Berg, Nikolaj Drimer; Linneberg, Allan; Thyssen, Jacob Pontoppidan

    2011-01-01

    the relationship between cutaneous reactions from patch testing and self-reported severity of chemical sensitivity to common airborne chemicals. A total of 3460 individuals participating in a general health examination, Health 2006, were patch tested with allergens from the European standard series and screened...... most severe groups of self-reported sensitivity to airborne chemicals. When adjusting for confounding, associations were weakened, and only non-allergic cutaneous reactions were significantly associated with individuals most severely affected by inhalation of airborne chemicals (odds ratio = 2.5, p = 0...

  3. Alternative analysis of airborne laser data collected within conventional multi-parameter airborne geophysical surveys

    Science.gov (United States)

    Ahl, Andreas; Supper, R.; Motschka, K.; Schattauer, I.

    2010-05-01

    For the interpretation of airborne gamma-ray spectrometry as well as airborne electromagnetics it is of great importance to determine the distance between the geophysical sensor and the ground surface. Since radar altimeters do not penetrate vegetation, laser altimeters became popular in airborne geophysics over the past years. Currently the airborne geophysical platform of the Geological Survey of Austria (GBA) is equipped with a Riegl LD90-3800VHS-FLP high resolution laser altimeter, measuring the distances according to the first and the last reflected pulse. The goal of the presented study was to explore the possibilities of deriving additional information about the survey area from the laser data and to determine the accuracy of such results. On one hand the difference between the arrival time of the first and the last reflected pulse can be used to determine the height of the vegetation. This parameter is for example important for the correction of damping effects on airborne gamma-ray measurements caused by vegetation. Moreover especially for groundwater studies at catchment scale, this parameter can also be applied to support the spatial assessment of evapotranspiration. In combination with the altitude above geoid, determined by a GPS receiver, a rough digital elevation model of the survey area can be derived from the laser altimetry. Based on a data set from a survey area in the northern part of Austria, close to the border with the Czech Republic, the reliability of such a digital elevation model and the calculated vegetation height was tested. In this study a mean deviation of -1.4m, with a standard deviation of ±3.4m, between the digital elevation model from Upper Austria (25m spatial resolution) and the determined elevation model was determined. We also found an obvious correlation between the calculated vegetation heights greater 15m and the mapped forest published by the ‘Department of Forest Inventory' of the ‘Federal Forest Office' of Austria

  4. Routing architecture and security for airborne networks

    Science.gov (United States)

    Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

    2009-05-01

    Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

  5. Airborne radionuclide waste-management reference document

    International Nuclear Information System (INIS)

    Brown, R.A.; Christian, J.D.; Thomas, T.R.

    1983-07-01

    This report provides the detailed data required to develop a strategy for airborne radioactive waste management by the Department of Energy (DOE). The airborne radioactive materials of primary concern are tritium (H-3), carbon-14 (C-14), krypton-85 (Kr-85), iodine-129 (I-129), and radioactive particulate matter. The introductory section of the report describes the nature and broad objectives of airborne waste management. The relationship of airborne waste management to other waste management programs is described. The scope of the strategy is defined by considering all potential sources of airborne radionuclides and technologies available for their management. Responsibilities of the regulatory agencies are discussed. Section 2 of this document deals primarily with projected inventories, potential releases, and dose commitments of the principal airborne wastes from the light water reactor (LWR) fuel cycle. In Section 3, dose commitments, technologies, costs, regulations, and waste management criteria are analyzed. Section 4 defines goals and objectives for airborne waste management

  6. Fundamental Structure of Loop Quantum Gravity

    Science.gov (United States)

    Han, Muxin; Ma, Yongge; Huang, Weiming

    In the recent twenty years, loop quantum gravity, a background independent approach to unify general relativity and quantum mechanics, has been widely investigated. The aim of loop quantum gravity is to construct a mathematically rigorous, background independent, non-perturbative quantum theory for a Lorentzian gravitational field on a four-dimensional manifold. In the approach, the principles of quantum mechanics are combined with those of general relativity naturally. Such a combination provides us a picture of, so-called, quantum Riemannian geometry, which is discrete on the fundamental scale. Imposing the quantum constraints in analogy from the classical ones, the quantum dynamics of gravity is being studied as one of the most important issues in loop quantum gravity. On the other hand, the semi-classical analysis is being carried out to test the classical limit of the quantum theory. In this review, the fundamental structure of loop quantum gravity is presented pedagogically. Our main aim is to help non-experts to understand the motivations, basic structures, as well as general results. It may also be beneficial to practitioners to gain insights from different perspectives on the theory. We will focus on the theoretical framework itself, rather than its applications, and do our best to write it in modern and precise langauge while keeping the presentation accessible for beginners. After reviewing the classical connection dynamical formalism of general relativity, as a foundation, the construction of the kinematical Ashtekar-Isham-Lewandowski representation is introduced in the content of quantum kinematics. The algebraic structure of quantum kinematics is also discussed. In the content of quantum dynamics, we mainly introduce the construction of a Hamiltonian constraint operator and the master constraint project. At last, some applications and recent advances are outlined. It should be noted that this strategy of quantizing gravity can also be extended to

  7. Gravity where do we stand ?

    CERN Document Server

    Colpi, Monica; Gorini, Vittorio; Moschella, Ugo

    2016-01-01

    This book presents an overview of the current understanding of gravitation, with a focus on the current efforts to test its theories, especially general relativity. It shows how the quest for a deeper understanding, which would possibly incorporate gravity in the quantum realm, is more than ever an open field. The majority of the contributions deals with the manifold facets of “experimental gravitation”, but the book goes beyond this and covers a broad range of subjects from the foundations of gravitational theories to astrophysics and cosmology. The book is divided into three parts. The first part deals with foundations and Solar System tests. An introductory pedagogical chapter reviews first Newtonian gravitational theory, special relativity, the equivalence principle and the basics of general relativity. Then it focuses on approximation methods, mainly the post-Newtonian formalism and the relaxed Einstein equations, with a discussion on how they are used in treating experimental tests and in the proble...

  8. Nonlinearities in modified gravity cosmology: Signatures of modified gravity in the nonlinear matter power spectrum

    International Nuclear Information System (INIS)

    Cui Weiguang; Zhang Pengjie; Yang Xiaohu

    2010-01-01

    A large fraction of cosmological information on dark energy and gravity is encoded in the nonlinear regime. Precision cosmology thus requires precision modeling of nonlinearities in general dark energy and modified gravity models. We modify the Gadget-2 code and run a series of N-body simulations on modified gravity cosmology to study the nonlinearities. The modified gravity model that we investigate in the present paper is characterized by a single parameter ζ, which determines the enhancement of particle acceleration with respect to general relativity (GR), given the identical mass distribution (ζ=1 in GR). The first nonlinear statistics we investigate is the nonlinear matter power spectrum at k < or approx. 3h/Mpc, which is the relevant range for robust weak lensing power spectrum modeling at l < or approx. 2000. In this study, we focus on the relative difference in the nonlinear power spectra at corresponding redshifts where different gravity models have the same linear power spectra. This particular statistics highlights the imprint of modified gravity in the nonlinear regime and the importance of including the nonlinear regime in testing GR. By design, it is less susceptible to the sample variance and numerical artifacts. We adopt a mass assignment method based on wavelet to improve the power spectrum measurement. We run a series of tests to determine the suitable simulation specifications (particle number, box size, and initial redshift). We find that, the nonlinear power spectra can differ by ∼30% for 10% deviation from GR (|ζ-1|=0.1) where the rms density fluctuations reach 10. This large difference, on one hand, shows the richness of information on gravity in the corresponding scales, and on the other hand, invalidates simple extrapolations of some existing fitting formulae to modified gravity cosmology.

  9. Rates of volcanic CO2 degassing from airborne determinations of SO2 Emission rates and plume CO2SO2: test study at Pu′u ′O′o Cone, Kilauea Volcano, Hawaii

    Science.gov (United States)

    Gerlach, Terrence M.; McGee, Kenneth A.; Sutton, A. Jefferson; Elias, Tamar

    1998-01-01

    We present an airborne method that eliminates or minimizes several disadvantages of the customary plume cross-section sampling method for determining volcanic CO2 emission rates. A LI-COR CO2analyzer system (LICOR), a Fourier transform infrared spectrometer system (FTIR), and a correlation spectrometer (COSPEC) were used to constrain the plume CO2/SO2 and the SO2 emission rate. The method yielded a CO2 emission rate of 300 td−1 (metric tons per day) for Pu′u ′O′o cone, Kilauea volcano, on 19 September 1995. The CO2/SO2 of 0.20 determined from airborne LICOR and FTIR plume measurements agreed with the CO2/SO2 of 204 ground-based samples collected from vents over a 14-year period since the Pu′u ′O′o eruption began in January 1983.

  10. Gravity Data for South America

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (152,624 records) were compiled by the University of Texas at Dallas. This data base was received in June 1992. Principal gravity parameters...

  11. Interior Alaska Gravity Station Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data total 9416 records. This data base was received in March 1997. Principal gravity parameters include Free-air Anomalies which have been...

  12. Gravity Station Data for Spain

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data total 28493 records. This data base was received in April 1997. Principal gravity parameters include Free-air Anomalies which have been...

  13. Gravity Station Data for Portugal

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data total 3064 records. This data base was received in April 1997. Principal gravity parameters include Free-air Anomalies which have been...

  14. Internal model of gravity influences configural body processing.

    Science.gov (United States)

    Barra, Julien; Senot, Patrice; Auclair, Laurent

    2017-01-01

    Human bodies are processed by a configural processing mechanism. Evidence supporting this claim is the body inversion effect, in which inversion impairs recognition of bodies more than other objects. Biomechanical configuration, as well as both visual and embodied expertise, has been demonstrated to play an important role in this effect. Nevertheless, the important factor of body inversion effect may also be linked to gravity orientation since gravity is one of the most fundamental constraints of our biology, behavior, and perception on Earth. The visual presentation of an inverted body in a typical body inversion paradigm turns the observed body upside down but also inverts the implicit direction of visual gravity in the scene. The orientation of visual gravity is then in conflict with the direction of actual gravity and may influence configural processing. To test this hypothesis, we dissociated the orientations of the body and of visual gravity by manipulating body posture. In a pretest we showed that it was possible to turn an avatar upside down (inversion relative to retinal coordinates) without inverting the orientation of visual gravity when the avatar stands on his/her hands. We compared the inversion effect in typical conditions (with gravity conflict when the avatar is upside down) to the inversion effect in conditions with no conflict between visual and physical gravity. The results of our experiment revealed that the inversion effect, as measured by both error rate and reaction time, was strongly reduced when there was no gravity conflict. Our results suggest that when an observed body is upside down (inversion relative to participants' retinal coordinates) but the orientation of visual gravity is not, configural processing of bodies might still be possible. In this paper, we discuss the implications of an internal model of gravity in the configural processing of observed bodies. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Airborne geophysical survey of the catastrophic landslide at Stože, Log pod Mangrtom, as a test of an innovative approach for landslide mapping in steep alpine terrains

    Directory of Open Access Journals (Sweden)

    I. Baroň

    2013-10-01

    Full Text Available Airborne geophysics is a promising method for investigating landslides. Here we present a case study of multisensor airborne geophysical survey at the catastrophic landslide Stože near Log pod Mangrtom in Slovenia, which was conducted in the framework of the European FP7th Project "SafeLand". Based on the survey itself and achieved results, we discuss applicability, limits, and benefits and costs of the method for investigating landslides in steep alpine terrains. Despite of several operational constraints, the airborne electromagnetic survey of the area well presented the lithological pattern and water saturation. The high resistivity regions mostly indicated drained slope scree and landslide mass, drained and loosened material of the moraine deposit in the tension zone of the landslide with present cracks and cavities. The minima of the resistivity pattern were attributed to the outcrop of marls rich in clay, to water-saturated moraine deposit above impermeable marls in the tension zone, and to water-saturated porous alluvial gravel and landslide scree along the Koritnica River. The magnetic survey proved to be inapplicable for such a small and rough area. The Potassium and Thorium maps, on the other hand, both well identified the regions of tension inside the landslide zone, outcrops of marls and dolomite, clay-rich colluvium, weathered zones along a regional tectonic fault, and alluvial deposits and deposits of debris flows, and the minima of the 137Cs clearly revealed the zones of material removal due to recent mass movements.

  16. Gravitational microlensing in Verlinde's emergent gravity

    NARCIS (Netherlands)

    Liu, Leihua; Prokopec, Tom

    2017-01-01

    We propose gravitational microlensing as a way of testing the emergent gravity theory recently proposed by Eric Verlinde [1]. We consider two limiting cases: the dark mass of maximally anisotropic pressures (Case I) and of isotropic pressures (Case II). Our analysis of perihelion advancement of a

  17. Beyond metric gravity: Progress on PS-200

    International Nuclear Information System (INIS)

    Goldman, T.; Brown, R.E.; Camp, J.B.; Darling, T.; Dyer, P.; Holzscheiter, M.H.; Hughes, R.J.; Jarmie, N.; King, N.S.P.; Lizon, D.C.; Nieto, M.M.; Schauer, M.M.M.; Schecker, J.A.; Cornford, S.; Hosea, K.; Kenefick, R.A.; Hoibraaten, S.; Midzor, M.M.; Parry, S.P.; Ristenen, R.A.; Witteborn, F.C.

    1993-01-01

    The reconciliation of quantum mechanics and gravity on varying distance scales requires changes to General Relativity that may be testable implications. We briefly review the status of tests with matter of the inverse square law and the principle of equivalence, then report on progress on the drift-tube measurement section of PS- 200, the experiment to measure the gravitational acceleration of antiprotons

  18. Antigravity: Spin-gravity coupling in action

    Science.gov (United States)

    Plyatsko, Roman; Fenyk, Mykola

    2016-08-01

    The typical motions of a spinning test particle in Schwarzschild's background which show the strong repulsive action of the highly relativistic spin-gravity coupling are considered using the exact Mathisson-Papapetrou equations. An approximated approach to choice solutions of these equations which describe motions of the particle's proper center of mass is developed.

  19. Loop quantum gravity: an outside view

    International Nuclear Information System (INIS)

    Nicolai, Hermann; Peeters, Kasper; Zamaklar, Marija

    2005-01-01

    We review aspects of loop quantum gravity in a pedagogical manner, with the aim of enabling a precise but critical assessment of its achievements so far. We emphasize that the off-shell ('strong') closure of the constraint algebra is a crucial test of quantum spacetime covariance, and thereby of the consistency, of the theory. Special attention is paid to the appearance of a large number of ambiguities, in particular in the formulation of the Hamiltonian constraint. Developing suitable approximation methods to establish a connection with classical gravity on the one hand, and with the physics of elementary particles on the other, remains a major challenge. (topical review)

  20. APEX - the Hyperspectral ESA Airborne Prism Experiment

    Directory of Open Access Journals (Sweden)

    Koen Meuleman

    2008-10-01

    Full Text Available The airborne ESA-APEX (Airborne Prism Experiment hyperspectral mission simulator is described with its distinct specifications to provide high quality remote sensing data. The concept of an automatic calibration, performed in the Calibration Home Base (CHB by using the Control Test Master (CTM, the In-Flight Calibration facility (IFC, quality flagging (QF and specific processing in a dedicated Processing and Archiving Facility (PAF, and vicarious calibration experiments are presented. A preview on major applications and the corresponding development efforts to provide scientific data products up to level 2/3 to the user is presented for limnology, vegetation, aerosols, general classification routines and rapid mapping tasks. BRDF (Bidirectional Reflectance Distribution Function issues are discussed and the spectral database SPECCHIO (Spectral Input/Output introduced. The optical performance as well as the dedicated software utilities make APEX a state-of-the-art hyperspectral sensor, capable of (a satisfying the needs of several research communities and (b helping the understanding of the Earth’s complex mechanisms.

  1. Massive Conformal Gravity

    International Nuclear Information System (INIS)

    Faria, F. F.

    2014-01-01

    We construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depends on the metric tensor and a scalar field, which are considered the only field variables. We find the vacuum field equations of the theory and analyze its weak-field approximation and Newtonian limit.

  2. Colossal creations of gravity

    DEFF Research Database (Denmark)

    Skielboe, Andreas

    Gravity governs the evolution of the universe on the largest scales, and powers some of the most extreme objects at the centers of galaxies. Determining the masses and kinematics of galaxy clusters provides essential constraints on the large-scale structure of the universe, and act as direct probes...

  3. A Trick of Gravity

    Science.gov (United States)

    Newburgh, Ronald

    2010-01-01

    It's both surprising and rewarding when an old, standard problem reveals a subtlety that expands its pedagogic value. I realized recently that the role of gravity in the range equation for a projectile is not so simple as first appears. This realization may be completely obvious to others but was quite new to me.

  4. Discrete Lorentzian quantum gravity

    NARCIS (Netherlands)

    Loll, R.

    2000-01-01

    Just as for non-abelian gauge theories at strong coupling, discrete lattice methods are a natural tool in the study of non-perturbative quantum gravity. They have to reflect the fact that the geometric degrees of freedom are dynamical, and that therefore also the lattice theory must be formulated

  5. Loop quantum gravity

    International Nuclear Information System (INIS)

    Pullin, J.

    2015-01-01

    Loop quantum gravity is one of the approaches that are being studied to apply the rules of quantum mechanics to the gravitational field described by the theory of General Relativity . We present an introductory summary of the main ideas and recent results. (Author)

  6. A finite quantum gravity

    International Nuclear Information System (INIS)

    Meszaros, A.

    1984-05-01

    In case the graviton has a very small non-zero mass, the existence of six additional massive gravitons with very big masses leads to a finite quantum gravity. There is an acausal behaviour on the scales that is determined by the masses of additional gravitons. (author)

  7. Venus - Ishtar gravity anomaly

    Science.gov (United States)

    Sjogren, W. L.; Bills, B. G.; Mottinger, N. A.

    1984-01-01

    The gravity anomaly associated with Ishtar Terra on Venus is characterized, comparing line-of-sight acceleration profiles derived by differentiating Pioneer Venus Orbiter Doppler residual profiles with an Airy-compensated topographic model. The results are presented in graphs and maps, confirming the preliminary findings of Phillips et al. (1979). The isostatic compensation depth is found to be 150 + or - 30 km.

  8. Torsion induces gravity

    International Nuclear Information System (INIS)

    Aros, Rodrigo; Contreras, Mauricio

    2006-01-01

    In this work the Poincare-Chern-Simons and anti-de Sitter-Chern-Simons gravities are studied. For both, a solution that can be cast as a black hole with manifest torsion is found. Those solutions resemble Schwarzschild and Schwarzschild-AdS solutions, respectively

  9. Discrete quantum gravity

    International Nuclear Information System (INIS)

    Williams, J.W.

    1992-01-01

    After a brief introduction to Regge calculus, some examples of its application is quantum gravity are described in this paper. In particular, the earliest such application, by Ponzano and Regge, is discussed in some detail and it is shown how this leads naturally to current work on invariants of three-manifolds

  10. Loop Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Rovelli Carlo

    1998-01-01

    Full Text Available The problem of finding the quantum theory of the gravitational field, and thus understanding what is quantum spacetime, is still open. One of the most active of the current approaches is loop quantum gravity. Loop quantum gravity is a mathematically well-defined, non-perturbative and background independent quantization of general relativity, with its conventional matter couplings. Research in loop quantum gravity today forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained are: (i The computation of the physical spectra of geometrical quantities such as area and volume, which yields quantitative predictions on Planck-scale physics. (ii A derivation of the Bekenstein-Hawking black hole entropy formula. (iii An intriguing physical picture of the microstructure of quantum physical space, characterized by a polymer-like Planck scale discreteness. This discreteness emerges naturally from the quantum theory and provides a mathematically well-defined realization of Wheeler's intuition of a spacetime ``foam''. Long standing open problems within the approach (lack of a scalar product, over-completeness of the loop basis, implementation of reality conditions have been fully solved. The weak part of the approach is the treatment of the dynamics: at present there exist several proposals, which are intensely debated. Here, I provide a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.

  11. Massive gravity wrapped in the cosmic web

    International Nuclear Information System (INIS)

    Shim, Junsup; Lee, Jounghun; Li, Baojiu

    2014-01-01

    We study how the filamentary pattern of the cosmic web changes if the true gravity deviates from general relativity (GR) on a large scale. The f(R) gravity, whose strength is controlled to satisfy the current observational constraints on the cluster scale, is adopted as our fiducial model and a large, high-resolution N-body simulation is utilized for this study. By applying the minimal spanning tree algorithm to the halo catalogs from the simulation at various epochs, we identify the main stems of the rich superclusters located in the most prominent filamentary section of the cosmic web and determine their spatial extents per member cluster to be the degree of their straightness. It is found that the f(R) gravity has the effect of significantly bending the superclusters and that the effect becomes stronger as the universe evolves. Even in the case where the deviation from GR is too small to be detectable by any other observables, the degree of the supercluster straightness exhibits a conspicuous difference between the f(R) and the GR models. Our results also imply that the supercluster straightness could be a useful discriminator of f(R) gravity from the coupled dark energy since it is shown to evolve differently between the two models. As a final conclusion, the degree of the straightness of the rich superclusters should provide a powerful cosmological test of large scale gravity.

  12. Massive gravity wrapped in the cosmic web

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Junsup; Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Li, Baojiu, E-mail: jsshim@astro.snu.ac.kr, E-mail: jounghun@astro.snu.ac.kr [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)

    2014-03-20

    We study how the filamentary pattern of the cosmic web changes if the true gravity deviates from general relativity (GR) on a large scale. The f(R) gravity, whose strength is controlled to satisfy the current observational constraints on the cluster scale, is adopted as our fiducial model and a large, high-resolution N-body simulation is utilized for this study. By applying the minimal spanning tree algorithm to the halo catalogs from the simulation at various epochs, we identify the main stems of the rich superclusters located in the most prominent filamentary section of the cosmic web and determine their spatial extents per member cluster to be the degree of their straightness. It is found that the f(R) gravity has the effect of significantly bending the superclusters and that the effect becomes stronger as the universe evolves. Even in the case where the deviation from GR is too small to be detectable by any other observables, the degree of the supercluster straightness exhibits a conspicuous difference between the f(R) and the GR models. Our results also imply that the supercluster straightness could be a useful discriminator of f(R) gravity from the coupled dark energy since it is shown to evolve differently between the two models. As a final conclusion, the degree of the straightness of the rich superclusters should provide a powerful cosmological test of large scale gravity.

  13. A Monte Carlo approach to constraining uncertainties in modelled downhole gravity gradiometry applications

    Science.gov (United States)

    Matthews, Samuel J.; O'Neill, Craig; Lackie, Mark A.

    2017-06-01

    Gravity gradiometry has a long legacy, with airborne/marine applications as well as surface applications receiving renewed recent interest. Recent instrumental advances has led to the emergence of downhole gravity gradiometry applications that have the potential for greater resolving power than borehole gravity alone. This has promise in both the petroleum and geosequestration industries; however, the effect of inherent uncertainties in the ability of downhole gravity gradiometry to resolve a subsurface signal is unknown. Here, we utilise the open source modelling package, Fatiando a Terra, to model both the gravity and gravity gradiometry responses of a subsurface body. We use a Monte Carlo approach to vary the geological structure and reference densities of the model within preset distributions. We then perform 100 000 simulations to constrain the mean response of the buried body as well as uncertainties in these results. We varied our modelled borehole to be either centred on the anomaly, adjacent to the anomaly (in the x-direction), and 2500 m distant to the anomaly (also in the x-direction). We demonstrate that gravity gradiometry is able to resolve a reservoir-scale modelled subsurface density variation up to 2500 m away, and that certain gravity gradient components (Gzz, Gxz, and Gxx) are particularly sensitive to this variation in gravity/gradiometry above the level of uncertainty in the model. The responses provided by downhole gravity gradiometry modelling clearly demonstrate a technique that can be utilised in determining a buried density contrast, which will be of particular use in the emerging industry of CO2 geosequestration. The results also provide a strong benchmark for the development of newly emerging prototype downhole gravity gradiometers.

  14. Airborne Next: Rethinking Airborne Organization and Applying New Concepts

    Science.gov (United States)

    2015-06-01

    9 Kenneth Macksey, Guderian: Panzer General-revised EDITION (South Yorkshire, England: Greenhill Books, 2003), 1–20. 10 Dr. John Arquilla...Airborne Operations: Field Manual 90=26, 1–5. 14 The 1st Special Forces Regiment has five active Special Forces Groups (1st, 3rd, 5th , 7th, 10th...Oxford University Press, 1981). Headrick, in his book, describes the interplay between technology and imperialism. For the purposes of this research

  15. Quantum Gravity Effects in Cosmology

    Directory of Open Access Journals (Sweden)

    Gu Je-An

    2018-01-01

    Full Text Available Within the geometrodynamic approach to quantum cosmology, we studied the quantum gravity effects in cosmology. The Gibbons-Hawking temperature is corrected by quantum gravity due to spacetime fluctuations and the power spectrum as well as any probe field will experience the effective temperature, a quantum gravity effect.

  16. Even-dimensional topological gravity from Chern-Simons gravity

    International Nuclear Information System (INIS)

    Merino, N.; Perez, A.; Salgado, P.

    2009-01-01

    It is shown that the topological action for gravity in 2n-dimensions can be obtained from the (2n+1)-dimensional Chern-Simons gravity genuinely invariant under the Poincare group. The 2n-dimensional topological gravity is described by the dynamics of the boundary of a (2n+1)-dimensional Chern-Simons gravity theory with suitable boundary conditions. The field φ a , which is necessary to construct this type of topological gravity in even dimensions, is identified with the coset field associated with the non-linear realizations of the Poincare group ISO(d-1,1).

  17. Astrophysical black holes in screened modified gravity

    International Nuclear Information System (INIS)

    Davis, Anne-Christine; Jha, Rahul; Muir, Jessica; Gregory, Ruth

    2014-01-01

    Chameleon, environmentally dependent dilaton, and symmetron gravity are three models of modified gravity in which the effects of the additional scalar degree of freedom are screened in dense environments. They have been extensively studied in laboratory, cosmological, and astrophysical contexts. In this paper, we present a preliminary investigation into whether additional constraints can be provided by studying these scalar fields around black holes. By looking at the properties of a static, spherically symmetric black hole, we find that the presence of a non-uniform matter distribution induces a non-constant scalar profile in chameleon and dilaton, but not necessarily symmetron gravity. An order of magnitude estimate shows that the effects of these profiles on in-falling test particles will be sub-leading compared to gravitational waves and hence observationally challenging to detect

  18. Astrophysical black holes in screened modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Anne-Christine; Jha, Rahul; Muir, Jessica [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Gregory, Ruth, E-mail: acd@damtp.cam.ac.uk, E-mail: r.a.w.gregory@durham.ac.uk, E-mail: r.jha@damtp.cam.ac.uk, E-mail: jlmuir@umich.edu [Centre for Particle Theory, South Road, Durham, DH1 3LE (United Kingdom)

    2014-08-01

    Chameleon, environmentally dependent dilaton, and symmetron gravity are three models of modified gravity in which the effects of the additional scalar degree of freedom are screened in dense environments. They have been extensively studied in laboratory, cosmological, and astrophysical contexts. In this paper, we present a preliminary investigation into whether additional constraints can be provided by studying these scalar fields around black holes. By looking at the properties of a static, spherically symmetric black hole, we find that the presence of a non-uniform matter distribution induces a non-constant scalar profile in chameleon and dilaton, but not necessarily symmetron gravity. An order of magnitude estimate shows that the effects of these profiles on in-falling test particles will be sub-leading compared to gravitational waves and hence observationally challenging to detect.

  19. Solar system constraints on disformal gravity theories

    International Nuclear Information System (INIS)

    Ip, Hiu Yan; Schmidt, Fabian; Sakstein, Jeremy

    2015-01-01

    Disformal theories of gravity are scalar-tensor theories where the scalar couples derivatively to matter via the Jordan frame metric. These models have recently attracted interest in the cosmological context since they admit accelerating solutions. We derive the solution for a static isolated mass in generic disformal gravity theories and transform it into the parameterised post-Newtonian form. This allows us to investigate constraints placed on such theories by local tests of gravity. The tightest constraints come from preferred-frame effects due to the motion of the Solar System with respect to the evolving cosmological background field. The constraints we obtain improve upon the previous solar system constraints by two orders of magnitude, and constrain the scale of the disformal coupling for generic models to ℳ ∼> 100 eV. These constraints render all disformal effects irrelevant for cosmology

  20. Virtual Gravity and the Duality of Reality

    CERN Document Server

    Harokopos, E

    2003-01-01

    It is shown that a hypothesis about gravity having a virtual cause implies there are two primary reference frames, a reality and a functional virtual reality and an equivalence principle relating the two is postulated. A mathematical expression relating the primary reference frames to the state of reality provides an explanation of particle-wave duality and resolves the controversy about the speed of gravity. A model for motion, time and particle formation is briefly discussed, in which the hypothesis about the virtual cause of gravity and supporting postulates are valid. It is further shown that such model provides solutions to unsolved paradoxes and a unification of consistent but contradictory ancient theories of matter and motion. Finally, a reference is made about the basis for devising experiments and testing the predictions of the model.

  1. GEODYNAMIC WAVES AND GRAVITY

    Directory of Open Access Journals (Sweden)

    A. V. Vikulin

    2014-01-01

    Full Text Available  Gravity phenomena related to the Earth movements in the Solar System and through the Galaxy are reviewed. Such movements are manifested by geological processes on the Earth and correlate with geophysical fields of the Earth. It is concluded that geodynamic processes and the gravity phenomena (including those of cosmic nature are related.  The state of the geomedium composed of blocks is determined by stresses with force moment and by slow rotational waves that are considered as a new type of movements [Vikulin, 2008, 2010]. It is shown that the geomedium has typical rheid properties [Carey, 1954], specifically an ability to flow while being in the solid state [Leonov, 2008]. Within the framework of the rotational model with a symmetric stress tensor, which is developed by the authors [Vikulin, Ivanchin, 1998; Vikulin et al., 2012a, 2013], such movement of the geomedium may explain the energy-saturated state of the geomedium and a possibility of its movements in the form of vortex geological structures [Lee, 1928]. The article discusses the gravity wave detection method based on the concept of interactions between gravity waves and crustal blocks [Braginsky et al., 1985]. It is concluded that gravity waves can be recorded by the proposed technique that detects slow rotational waves. It is shown that geo-gravitational movements can be described by both the concept of potential with account of gravitational energy of bodies [Kondratyev, 2003] and the nonlinear physical acoustics [Gurbatov et al., 2008]. Based on the combined description of geophysical and gravitational wave movements, the authors suggest a hypothesis about the nature of spin, i.e. own moment as a demonstration of the space-time ‘vortex’ properties.  

  2. Pig Farmers' Homes Harbor More Diverse Airborne Bacterial Communities Than Pig Stables or Suburban Homes.

    Science.gov (United States)

    Vestergaard, Ditte V; Holst, Gitte J; Basinas, Ioannis; Elholm, Grethe; Schlünssen, Vivi; Linneberg, Allan; Šantl-Temkiv, Tina; Finster, Kai; Sigsgaard, Torben; Marshall, Ian P G

    2018-01-01

    Airborne bacterial communities are subject to conditions ill-suited to microbial activity and growth. In spite of this, air is an important transfer medium for bacteria, with the bacteria in indoor air having potentially major consequences for the health of a building's occupants. A major example is the decreased diversity and altered composition of indoor airborne microbial communities as a proposed explanation for the increasing prevalence of asthma and allergies worldwide. Previous research has shown that living on a farm confers protection against development of asthma and allergies, with airborne bacteria suggested as playing a role in this protective effect. However, the composition of this beneficial microbial community has still not been identified. We sampled settled airborne dust using a passive dust sampler from Danish pig stables, associated farmers' homes, and from suburban homes (267 samples in total) and carried out quantitative PCR measurements of bacterial abundance and MiSeq sequencing of the V3-V4 region of bacterial 16S rRNA genes found in these samples. Airborne bacteria had a greater diversity and were significantly more abundant in pig stables and farmers' homes than suburban homes (Wilcoxon rank sum test P < 0.05). Moreover, bacterial taxa previously suggested to contribute to a protective effect had significantly higher relative and absolute abundance in pig stables and farmers' homes than in suburban homes (ALDEx2 with P < 0.05), including Firmicutes, Peptostreptococcaceae, Prevotellaceae, Lachnospiraceae, Ruminococcaceae, Ruminiclostridium , and Lactobacillus . Pig stables had significantly lower airborne bacterial diversity than farmers' homes, and there was no discernable direct transfer of airborne bacteria from stable to home. This study identifies differences in indoor airborne bacterial communities that may be an important component of this putative protective effect, while showing that pig stables themselves do not appear to

  3. Improving Realism in Reduced Gravity Simulators

    Science.gov (United States)

    Cowley, Matthew; Harvil, Lauren; Clowers, Kurt; Clark, Timothy; Rajulu, Sudhakar

    2010-01-01

    Since man was first determined to walk on the moon, simulating the lunar environment became a priority. Providing an accurate reduced gravity environment is crucial for astronaut training and hardware testing. This presentation will follow the development of reduced gravity simulators to a final comparison of environments between the currently used systems. During the Apollo program era, multiple systems were built and tested, with several NASA centers having their own unique device. These systems ranged from marionette-like suspension devices where the subject laid on his side, to pneumatically driven offloading harnesses, to parabolic flights. However, only token comparisons, if any, were made between systems. Parabolic flight allows the entire body to fall at the same rate, giving an excellent simulation of reduced gravity as far as the biomechanics and physical perceptions are concerned. While the effects are accurate, there is limited workspace, limited time, and high cost associated with these tests. With all mechanical offload systems only the parts of the body that are actively offloaded feel any reduced gravity effects. The rest of the body still feels the full effect of gravity. The Partial Gravity System (Pogo) is the current ground-based offload system used to training and testing at the NASA Johnson Space Center. The Pogo is a pneumatic type system that allows for offloaded motion in the z-axis and free movement in the x-axis, but has limited motion in the y-axis. The pneumatic system itself is limited by cylinder stroke length and response time. The Active Response Gravity Offload System (ARGOS) is a next generation groundbased offload system, currently in development, that is based on modern robotic manufacturing lines. This system is projected to provide more z-axis travel and full freedom in both the x and y-axes. Current characterization tests are underway to determine how the ground-based offloading systems perform, how they compare to parabolic

  4. Metastable gravity on classical defects

    International Nuclear Information System (INIS)

    Ringeval, Christophe; Rombouts, Jan-Willem

    2005-01-01

    We discuss the realization of metastable gravity on classical defects in infinite-volume extra dimensions. In dilatonic Einstein gravity, it is found that the existence of metastable gravity on the defect core requires violation of the dominant energy condition for codimension N c =2 defects. This is illustrated with a detailed analysis of a six-dimensional hyperstring minimally coupled to dilaton gravity. We present the general conditions under which a codimension N c >2 defect admits metastable modes, and find that they differ from lower codimensional models in that, under certain conditions, they do not require violation of energy conditions to support quasilocalized gravity

  5. Airborne microorganisms from waste containers.

    Science.gov (United States)

    Jedlicka, Sabrina S; Stravitz, David M; Lyman, Charles E

    2012-01-01

    In physician's offices and biomedical labs, biological waste is handled every day. This waste is disposed of in waste containers designed for holding red autoclave bags. The containers used in these environments are closed hands-free containers, often with a step pedal. While these containers protect the user from surface-borne microorganisms, the containers may allow airborne microorganisms to escape via the open/close mechanism because of the air current produced upon open/close cycles. In this study, the air current was shown to be sufficient to allow airborne escape of microorganisms held in the container, including Aspergillus niger. However, bacterial cultures, such as Escherichia coli and Lactococcus lactis did not escape. This may be due to the choice of bacterial cultures and the absence of solid waste, such as dust or other particulate matter in the waste containers, that such strains of bacteria could travel on during aerosolization. We compared these results to those obtained using a re-designed receptacle, which mimimizes air currents, and detected no escaping microorganisms. This study highlights one potential source of airborne contamination in labs, hospitals, and other environments that dispose of biological waste.

  6. Airborne particulate matter in spacecraft

    Science.gov (United States)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  7. Quantum gravity from noncommutative spacetime

    International Nuclear Information System (INIS)

    Lee, Jungjai; Yang, Hyunseok

    2014-01-01

    We review a novel and authentic way to quantize gravity. This novel approach is based on the fact that Einstein gravity can be formulated in terms of a symplectic geometry rather than a Riemannian geometry in the context of emergent gravity. An essential step for emergent gravity is to realize the equivalence principle, the most important property in the theory of gravity (general relativity), from U(1) gauge theory on a symplectic or Poisson manifold. Through the realization of the equivalence principle, which is an intrinsic property in symplectic geometry known as the Darboux theorem or the Moser lemma, one can understand how diffeomorphism symmetry arises from noncommutative U(1) gauge theory; thus, gravity can emerge from the noncommutative electromagnetism, which is also an interacting theory. As a consequence, a background-independent quantum gravity in which the prior existence of any spacetime structure is not a priori assumed but is defined by using the fundamental ingredients in quantum gravity theory can be formulated. This scheme for quantum gravity can be used to resolve many notorious problems in theoretical physics, such as the cosmological constant problem, to understand the nature of dark energy, and to explain why gravity is so weak compared to other forces. In particular, it leads to a remarkable picture of what matter is. A matter field, such as leptons and quarks, simply arises as a stable localized geometry, which is a topological object in the defining algebra (noncommutative *-algebra) of quantum gravity.

  8. Quantum gravity from noncommutative spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jungjai [Daejin University, Pocheon (Korea, Republic of); Yang, Hyunseok [Korea Institute for Advanced Study, Seoul (Korea, Republic of)

    2014-12-15

    We review a novel and authentic way to quantize gravity. This novel approach is based on the fact that Einstein gravity can be formulated in terms of a symplectic geometry rather than a Riemannian geometry in the context of emergent gravity. An essential step for emergent gravity is to realize the equivalence principle, the most important property in the theory of gravity (general relativity), from U(1) gauge theory on a symplectic or Poisson manifold. Through the realization of the equivalence principle, which is an intrinsic property in symplectic geometry known as the Darboux theorem or the Moser lemma, one can understand how diffeomorphism symmetry arises from noncommutative U(1) gauge theory; thus, gravity can emerge from the noncommutative electromagnetism, which is also an interacting theory. As a consequence, a background-independent quantum gravity in which the prior existence of any spacetime structure is not a priori assumed but is defined by using the fundamental ingredients in quantum gravity theory can be formulated. This scheme for quantum gravity can be used to resolve many notorious problems in theoretical physics, such as the cosmological constant problem, to understand the nature of dark energy, and to explain why gravity is so weak compared to other forces. In particular, it leads to a remarkable picture of what matter is. A matter field, such as leptons and quarks, simply arises as a stable localized geometry, which is a topological object in the defining algebra (noncommutative *-algebra) of quantum gravity.

  9. Design and Implementation of Wideband Exciter for an Ultra-high Resolution Airborne SAR System

    Directory of Open Access Journals (Sweden)

    Jia Ying-xin

    2013-03-01

    Full Text Available According to an ultra-high resolution airborne SAR system with better than 0.1 m resolution, a wideband Linear Frequency Modulated (LFM pulse compression exciter with 14.8 GHz carrier and 3.2 GHz bandwidth is designed and implemented. The selection of signal generation scheme and some key technique points for wideband LFM waveform is presented in detail. Then, an acute test and analysis of the LFM signal is performed. The final airborne experiments demonstrate the validity of the LFM source which is one of the subsystems in an ultra-high resolution airborne SAR system.

  10. Control of airborne microbes in a poultry setting using Dioxy MP 14

    Directory of Open Access Journals (Sweden)

    O Mbamalu

    2015-03-01

    Full Text Available In this study, Dioxy MP 14, a locally developed form of chlorine dioxide, was tested in a commercial chicken pen to determine its effectiveness as an airborne environmental sanitizing agent. The biocide was introduced via an overhead misting system with a variable dosing pump. The extent of airborne microbial control was determined with settle plates. Performance and mortality rate of the chickens in the experimental pen was compared to that in the control pen. Results show a decrease in airborne microbial load and a significantly higher egg productivity rate at a 5% level in the treated pen. However, no significant difference in mortality rates between the two pens was observed.

  11. Monitoring and evaluation techniques for airborne contamination

    Energy Technology Data Exchange (ETDEWEB)

    Yihua, Xia [China Inst. of Atomic Energy, Beijing (China)

    1997-06-01

    Monitoring and evaluation of airborne contamination are of great importance for the purpose of protection of health and safety of workers in nuclear installations. Because airborne contamination is one of the key sources to cause exposure to individuals by inhalation and digestion, and to cause diffusion of contaminants in the environment. The main objectives of monitoring and evaluation of airborne contamination are: to detect promptly a loss of control of airborne material, to help identify those individuals and predict exposure levels, to assess the intake and dose commitment to the individuals, and to provide sufficient documentation of airborne radioactivity. From the viewpoint of radiation protection, the radioactive contaminants in air can be classified into the following types: airborne aerosol, gas and noble gas, and volatile gas. In this paper, the following items are described: sampling methods and techniques, measurement and evaluation, and particle size analysis. (G.K.)

  12. Monitoring and evaluation techniques for airborne contamination

    International Nuclear Information System (INIS)

    Xia Yihua

    1997-01-01

    Monitoring and evaluation of airborne contamination are of great importance for the purpose of protection of health and safety of workers in nuclear installations. Because airborne contamination is one of the key sources to cause exposure to individuals by inhalation and digestion, and to cause diffusion of contaminants in the environment. The main objectives of monitoring and evaluation of airborne contamination are: to detect promptly a loss of control of airborne material, to help identify those individuals and predict exposure levels, to assess the intake and dose commitment to the individuals, and to provide sufficient documentation of airborne radioactivity. From the viewpoint of radiation protection, the radioactive contaminants in air can be classified into the following types: airborne aerosol, gas and noble gas, and volatile gas. In this paper, the following items are described: sampling methods and techniques, measurement and evaluation, and particle size analysis. (G.K.)

  13. New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica

    Science.gov (United States)

    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.

    2018-01-01

    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 levelling of the different gravity datasets 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 towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica. PMID:29326484

  14. Gas-laser behavior in a low-gravity environment

    Science.gov (United States)

    Owen, R. B.

    1981-01-01

    In connection with several experiments proposed for flight on the Space Shuttle, which involve the use of gas lasers, the behavior of a He-Ne laser in a low-gravity environment has been studied theoretically and experimentally in a series of flight tests using a low-gravity-simulation aircraft. No fluctuation in laser output above the noise level of the meter (1 part in 1000 for 1 hr) was observed during the low-gravity portion of the flight tests. The laser output gradually increased by 1.4% during a 1.5-hr test; at no time were rapid variations observed in the laser output. A maximum laser instability of 1 part in 100 was observed during forty low-gravity parabolic maneuvers. The beam remained Gaussian throughout the tests and no lobe patterns were observed.

  15. Unraveling Students' Misconceptions about the Earth's Shape and Gravity.

    Science.gov (United States)

    Sneider, Cary I.; Ohadi, Mark M.

    1998-01-01

    Presents a study designed to test the effectiveness of a constructivist-historical teaching strategy in changing students' misconceptions about the earth's shape and gravity at the upper elementary and middle school levels. Contains 27 references. (DDR)

  16. The relativistic gravity train

    Science.gov (United States)

    Seel, Max

    2018-05-01

    The gravity train that takes 42.2 min from any point A to any other point B that is connected by a straight-line tunnel through Earth has captured the imagination more than most other applications in calculus or introductory physics courses. Brachystochron and, most recently, nonlinear density solutions have been discussed. Here relativistic corrections are presented. It is discussed how the corrections affect the time to fall through Earth, the Sun, a white dwarf, a neutron star, and—the ultimate limit—the difference in time measured by a moving, a stationary and the fiducial observer at infinity if the density of the sphere approaches the density of a black hole. The relativistic gravity train can serve as a problem with approximate and exact analytic solutions and as numerical exercise in any introductory course on relativity.

  17. Antimatter gravity experiment

    International Nuclear Information System (INIS)

    Brown, R.E.; Camp, J.B.; Darling, T.W.

    1990-01-01

    An experiment is being developed to measure the acceleration of the antiproton in the gravitational field of the earth. Antiprotons of a few MeV from the LEAR facility at CERN will be slowed, captured, cooled to a temperature of about 10 K, and subsequently launched a few at a time into a drift tube where the effect of gravity on their motion will be determined by a time-of-flight method. Development of the experiment is proceeding at Los Alamos using normal matter. The fabrication of a drift tube that will produce a region of space in which gravity is the dominant force on moving ions is of major difficulty. This involves a study of methods of minimizing the electric fields produced by spatially varying work functions on conducting surfaces. Progress in a number of areas is described, with stress on the drift-tube development

  18. Lectures on Quantum Gravity

    CERN Document Server

    Gomberoff, Andres

    2006-01-01

    The 2002 Pan-American Advanced Studies Institute School on Quantum Gravity was held at the Centro de Estudios Cientificos (CECS),Valdivia, Chile, January 4-14, 2002. The school featured lectures by ten speakers, and was attended by nearly 70 students from over 14 countries. A primary goal was to foster interaction and communication between participants from different cultures, both in the layman’s sense of the term and in terms of approaches to quantum gravity. We hope that the links formed by students and the school will persist throughout their professional lives, continuing to promote interaction and the essential exchange of ideas that drives research forward. This volume contains improved and updated versions of the lectures given at the School. It has been prepared both as a reminder for the participants, and so that these pedagogical introductions can be made available to others who were unable to attend. We expect them to serve students of all ages well.

  19. Tensor Galileons and gravity

    Energy Technology Data Exchange (ETDEWEB)

    Chatzistavrakidis, Athanasios [Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Khoo, Fech Scen [Department of Physics and Earth Sciences, Jacobs University Bremen,Campus Ring 1, 28759 Bremen (Germany); Roest, Diederik [Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Schupp, Peter [Department of Physics and Earth Sciences, Jacobs University Bremen,Campus Ring 1, 28759 Bremen (Germany)

    2017-03-13

    The particular structure of Galileon interactions allows for higher-derivative terms while retaining second order field equations for scalar fields and Abelian p-forms. In this work we introduce an index-free formulation of these interactions in terms of two sets of Grassmannian variables. We employ this to construct Galileon interactions for mixed-symmetry tensor fields and coupled systems thereof. We argue that these tensors are the natural generalization of scalars with Galileon symmetry, similar to p-forms and scalars with a shift-symmetry. The simplest case corresponds to linearised gravity with Lovelock invariants, relating the Galileon symmetry to diffeomorphisms. Finally, we examine the coupling of a mixed-symmetry tensor to gravity, and demonstrate in an explicit example that the inclusion of appropriate counterterms retains second order field equations.

  20. Simplicial quantum gravity

    International Nuclear Information System (INIS)

    Hartle, J.B.

    1985-01-01

    Simplicial approximation and the ideas associated with the Regge calculus provide a concrete way of implementing a sum over histories formulation of quantum gravity. A simplicial geometry is made up of flat simplices joined together in a prescribed way together with an assignment of lengths to their edges. A sum over simplicial geometries is a sum over the different ways the simplices can be joined together with an integral over their edge lengths. The construction of the simplicial Euclidean action for this approach to quantum general relativity is illustrated. The recovery of the diffeomorphism group in the continuum limit is discussed. Some possible classes of simplicial complexes with which to define a sum over topologies are described. In two dimensional quantum gravity it is argued that a reasonable class is the class of pseudomanifolds

  1. ZPR-9 airborne plutonium monitoring system

    International Nuclear Information System (INIS)

    Rusch, G.K.; McDowell, W.P.; Knapp, W.G.

    1975-01-01

    An airborne plutonium monitoring system which is installed in the ZPR-9 (Zero Power Reactor No. 9) facility at Argonne National Laboratory is described. The design and operational experience are discussed. This monitoring system utilizes particle size and density discrimination, alpha particle energy discrimination, and a background-subtraction techique operating in cascade to separate airborne-plutonium activity from other, naturally occurring, airborne activity. Relatively high sensitivity and reliability are achieved

  2. Instantons and gravity

    International Nuclear Information System (INIS)

    Konopleva, N.P.

    1996-01-01

    The problems of application of nonperturbative quantization methods in the theories of the gauge fields and gravity are discussed. Unification of interactions is considered in the framework of the geometrical gauge fields theory. Vacuum conception in the unified theory of interactions and instantons role in the vacuum structure are analyzed. The role of vacuum solutions of Einstein equations in definition of the gauge field vacuum is demonstrated

  3. Gravity, Time, and Lagrangians

    Science.gov (United States)

    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…

  4. Spontaneously generated gravity

    International Nuclear Information System (INIS)

    Zee, A.

    1981-01-01

    We show, following a recent suggestion of Adler, that gravity may arise as a consequence of dynamical symmetry breaking in a scale- and gauge-invariant world. Our calculation is not tied to any specific scheme of dynamical symmetry breaking. A representation for Newton's coupling constant in terms of flat-space quantities is derived. The sign of Newton's coupling constant appears to depend on infrared details of the symmetry-breaking mechanism

  5. Loop Quantum Gravity.

    Science.gov (United States)

    Rovelli, Carlo

    2008-01-01

    The problem of describing the quantum behavior of gravity, and thus understanding quantum spacetime , is still open. Loop quantum gravity is a well-developed approach to this problem. It is a mathematically well-defined background-independent quantization of general relativity, with its conventional matter couplings. Today research in loop quantum gravity forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained so far are: (i) The computation of the spectra of geometrical quantities such as area and volume, which yield tentative quantitative predictions for Planck-scale physics. (ii) A physical picture of the microstructure of quantum spacetime, characterized by Planck-scale discreteness. Discreteness emerges as a standard quantum effect from the discrete spectra, and provides a mathematical realization of Wheeler's "spacetime foam" intuition. (iii) Control of spacetime singularities, such as those in the interior of black holes and the cosmological one. This, in particular, has opened up the possibility of a theoretical investigation into the very early universe and the spacetime regions beyond the Big Bang. (iv) A derivation of the Bekenstein-Hawking black-hole entropy. (v) Low-energy calculations, yielding n -point functions well defined in a background-independent context. The theory is at the roots of, or strictly related to, a number of formalisms that have been developed for describing background-independent quantum field theory, such as spin foams, group field theory, causal spin networks, and others. I give here a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.

  6. Loop Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Rovelli Carlo

    2008-07-01

    Full Text Available The problem of describing the quantum behavior of gravity, and thus understanding quantum spacetime, is still open. Loop quantum gravity is a well-developed approach to this problem. It is a mathematically well-defined background-independent quantization of general relativity, with its conventional matter couplings. Today research in loop quantum gravity forms a vast area, ranging from mathematical foundations to physical applications. Among the most significant results obtained so far are: (i The computation of the spectra of geometrical quantities such as area and volume, which yield tentative quantitative predictions for Planck-scale physics. (ii A physical picture of the microstructure of quantum spacetime, characterized by Planck-scale discreteness. Discreteness emerges as a standard quantum effect from the discrete spectra, and provides a mathematical realization of Wheeler’s “spacetime foam” intuition. (iii Control of spacetime singularities, such as those in the interior of black holes and the cosmological one. This, in particular, has opened up the possibility of a theoretical investigation into the very early universe and the spacetime regions beyond the Big Bang. (iv A derivation of the Bekenstein–Hawking black-hole entropy. (v Low-energy calculations, yielding n-point functions well defined in a background-independent context. The theory is at the roots of, or strictly related to, a number of formalisms that have been developed for describing background-independent quantum field theory, such as spin foams, group field theory, causal spin networks, and others. I give here a general overview of ideas, techniques, results and open problems of this candidate theory of quantum gravity, and a guide to the relevant literature.

  7. Semiclassical unimodular gravity

    International Nuclear Information System (INIS)

    Fiol, Bartomeu; Garriga, Jaume

    2010-01-01

    Classically, unimodular gravity is known to be equivalent to General Relativity (GR), except for the fact that the effective cosmological constant Λ has the status of an integration constant. Here, we explore various formulations of unimodular gravity beyond the classical limit. We first consider the non-generally covariant action formulation in which the determinant of the metric is held fixed to unity. We argue that the corresponding quantum theory is also equivalent to General Relativity for localized perturbative processes which take place in generic backgrounds of infinite volume (such as asymptotically flat spacetimes). Next, using the same action, we calculate semiclassical non-perturbative quantities, which we expect will be dominated by Euclidean instanton solutions. We derive the entropy/area ratio for cosmological and black hole horizons, finding agreement with GR for solutions in backgrounds of infinite volume, but disagreement for backgrounds with finite volume. In deriving the above results, the path integral is taken over histories with fixed 4-volume. We point out that the results are different if we allow the 4-volume of the different histories to vary over a continuum range. In this ''generalized'' version of unimodular gravity, one recovers the full set of Einstein's equations in the classical limit, including the trace, so Λ is no longer an integration constant. Finally, we consider the generally covariant theory due to Henneaux and Teitelboim, which is classically equivalent to unimodular gravity. In this case, the standard semiclassical GR results are recovered provided that the boundary term in the Euclidean action is chosen appropriately

  8. Venus gravity fields

    Science.gov (United States)

    Sjogren, W. L.; Ananda, M.; Williams, B. G.; Birkeland, P. W.; Esposito, P. S.; Wimberly, R. N.; Ritke, S. J.

    1981-01-01

    Results of Pioneer Venus Orbiter observations concerning the gravity field of Venus are presented. The gravitational data was obtained from reductions of Doppler radio tracking data for the Orbiter, which is in a highly eccentric orbit with periapsis altitude varying from 145 to 180 km and nearly fixed periapsis latitude of 15 deg N. The global gravity field was obtained through the simultaneous estimation of the orbit state parameters and gravity coefficients from long-period variations in orbital element rates. The global field has been described with sixth degree and order spherical harmonic coefficients, which are capable of resolving the three major topographical features on Venus. Local anomalies have been mapped using line-of-sight accelerations derived from the Doppler residuals between 40 deg N and 10 deg S latitude at approximately 300 km spatial resolution. Gravitational data is observed to correspond to topographical data obtained by radar altimeter, with most of the gravitational anomalies about 20-30 milligals. Simulations evaluating the isostatic states of two topographic features indicate that at least partial isostasy prevails, with the possibility of complete compensation.

  9. Determination of airborne nanoparticles from welding operations.

    Science.gov (United States)

    Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

    2012-01-01

    The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers.

  10. Dual channel airborne hygrometer for climate research

    Science.gov (United States)

    Tatrai, David; Gulyas, Gabor; Bozoki, Zoltan; Szabo, Gabor

    2015-04-01

    Airborne hygrometry has an increasing role in climate research and nowadays the determination of cloud content especially of cirrus clouds is gaining high interest. The greatest challenges for such measurements are being used from ground level up to the lower stratosphere with appropriate precision and accuracy the low concentration and varying environment pressure. Such purpose instrument was probably presented first by our research group [1-2]. The development of the system called WaSUL-Hygro and some measurement results will be introduced. The measurement system is based on photoacoustic spectroscopy and contains two measuring cells, one is used to measure water vapor concentration which is typically sampled by a sideward or backward inlet, while the second one measures total water content (water vapor plus ice crystals) after evaporation in a forward facing sampler. The two measuring cells are simultaneously illuminated through with one distributed feedback diode laser (1371 or 1392 nm). Two early versions have been used within the CARIBIC project. During the recent years, efforts were made to turn the system into a more reliable and robust one [3]. The first important development was the improvement of the wavelength stabilization method of the applied laser. As a result the uncertainty of the wavelength is less than 40fm, which corresponds to less than 0.05% of PA signal uncertainty. This PA signal uncertainty is lower than the noise level of the system itself. The other main development was the improvement of the concentration determination algorithm. For this purpose several calibration and data evaluation methods were developed, the combination of the latest ones have made the system traceable to the humidity generator applied during the calibration within 1.5% relative deviation or within noise level, whichever is greater. The improved system was several times blind tested at the Environmental Simulation Facility (Forschungszentrum Jülich, Germany) in

  11. Evaluation and comparison of the processing methods of airborne gravimetry concerning the errors effects on downward continuation results: Case studies in Louisiana (USA) and the Tibetan Plateau (China)

    DEFF Research Database (Denmark)

    Zhao, Qilong; Strykowski, Gabriel; Li, Jiancheng

    2017-01-01

    and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method...... in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA......) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic...

  12. Electrospray Collection of Airborne Contaminants, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In stark contrast to current stagnation-based methods for capturing airborne particulates and biological aerosols, our demonstrated, cost-effective electrospray...

  13. Recent developments in airborne gamma ray surveying

    International Nuclear Information System (INIS)

    Grasty, Robert L.

    1999-01-01

    Standardized procedures have been developed for converting airborne gamma ray measurements to ground concentrations of potassium, uranium and thorium. These procedures make use of an airborne calibration range whose ground concentrations should be measured with a calibrated portable spectrometer rather than by taking geochemical samples. Airborne sensitivities and height attenuation coefficients are normally determined from flights over the calibration range but may not be applicable in mountainous areas. Mathematical techniques have been now developed to reduce statistical noise in the airborne measurements by utilizing up to 256 channels of spectral information. (author)

  14. Challenges and Opportunities of Airborne Metagenomics

    KAUST Repository

    Behzad, H.; Gojobori, Takashi; Mineta, K.

    2015-01-01

    microorganisms. Airborne metagenomic studies could also lead to discoveries of novel genes and metabolic pathways relevant to meteorological and industrial applications, environmental bioremediation, and biogeochemical cycles.

  15. GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings

    Directory of Open Access Journals (Sweden)

    M. Ern

    2018-04-01

    Full Text Available Gravity waves are one of the main drivers of atmospheric dynamics. The spatial resolution of most global atmospheric models, however, is too coarse to properly resolve the small scales of gravity waves, which range from tens to a few thousand kilometers horizontally, and from below 1 km to tens of kilometers vertically. Gravity wave source processes involve even smaller scales. Therefore, general circulation models (GCMs and chemistry climate models (CCMs usually parametrize the effect of gravity waves on the global circulation. These parametrizations are very simplified. For this reason, comparisons with global observations of gravity waves are needed for an improvement of parametrizations and an alleviation of model biases. We present a gravity wave climatology based on atmospheric infrared limb emissions observed by satellite (GRACILE. GRACILE is a global data set of gravity wave distributions observed in the stratosphere and the mesosphere by the infrared limb sounding satellite instruments High Resolution Dynamics Limb Sounder (HIRDLS and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER. Typical distributions (zonal averages and global maps of gravity wave vertical wavelengths and along-track horizontal wavenumbers are provided, as well as gravity wave temperature variances, potential energies and absolute momentum fluxes. This global data set captures the typical seasonal variations of these parameters, as well as their spatial variations. The GRACILE data set is suitable for scientific studies, and it can serve for comparison with other instruments (ground-based, airborne, or other satellite instruments and for comparison with gravity wave distributions, both resolved and parametrized, in GCMs and CCMs. The GRACILE data set is available as supplementary data at https://doi.org/10.1594/PANGAEA.879658.

  16. GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings

    Science.gov (United States)

    Ern, Manfred; Trinh, Quang Thai; Preusse, Peter; Gille, John C.; Mlynczak, Martin G.; Russell, James M., III; Riese, Martin

    2018-04-01

    Gravity waves are one of the main drivers of atmospheric dynamics. The spatial resolution of most global atmospheric models, however, is too coarse to properly resolve the small scales of gravity waves, which range from tens to a few thousand kilometers horizontally, and from below 1 km to tens of kilometers vertically. Gravity wave source processes involve even smaller scales. Therefore, general circulation models (GCMs) and chemistry climate models (CCMs) usually parametrize the effect of gravity waves on the global circulation. These parametrizations are very simplified. For this reason, comparisons with global observations of gravity waves are needed for an improvement of parametrizations and an alleviation of model biases. We present a gravity wave climatology based on atmospheric infrared limb emissions observed by satellite (GRACILE). GRACILE is a global data set of gravity wave distributions observed in the stratosphere and the mesosphere by the infrared limb sounding satellite instruments High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). Typical distributions (zonal averages and global maps) of gravity wave vertical wavelengths and along-track horizontal wavenumbers are provided, as well as gravity wave temperature variances, potential energies and absolute momentum fluxes. This global data set captures the typical seasonal variations of these parameters, as well as their spatial variations. The GRACILE data set is suitable for scientific studies, and it can serve for comparison with other instruments (ground-based, airborne, or other satellite instruments) and for comparison with gravity wave distributions, both resolved and parametrized, in GCMs and CCMs. The GRACILE data set is available as supplementary data at https://doi.org/10.1594/PANGAEA.879658" target="_blank">https://doi.org/10.1594/PANGAEA.879658.

  17. Gravity and Heater Size Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Kim, Jungho; Raj, Rishi

    2014-01-01

    The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

  18. Centrifuge in Free Fall: Combustion at Partial Gravity

    Science.gov (United States)

    Ferkul, Paul

    2017-01-01

    A centrifuge apparatus is developed to study the effect of variable acceleration levels in a drop tower environment. It consists of a large rotating chamber, within which the experiment is conducted. NASA Glenn Research Center 5.18-second Zero-Gravity Facility drop tests were successfully conducted at rotation rates up to 1 RPS with no measurable effect on the overall Zero-Gravity drop bus. Arbitrary simulated gravity levels from zero to 1-g (at a radius of rotation 30 cm) were produced. A simple combustion experiment was used to exercise the capabilities of the centrifuge. A total of 23 drops burning a simulated candle with heptane and ethanol fuel were performed. The effect of gravity level (rotation rate) and Coriolis force on the flames was observed. Flames became longer, narrower, and brighter as gravity increased. The Coriolis force tended to tilt the flames to one side, as expected, especially as the rotation rate was increased. The Zero-Gravity Centrifuge can be a useful tool for other researchers interested in the effects of arbitrary partial gravity on experiments, especially as NASA embarks on future missions which may be conducted in non-Earth gravity.

  19. Assessment of long-range kinematic GPS positioning errors by comparison with airborne laser altimetry and satellite altimetry

    DEFF Research Database (Denmark)

    Zhang, X.H.; Forsberg, René

    2007-01-01

    Long-range airborne laser altimetry and laser scanning (LIDAR) or airborne gravity surveys in, for example, polar or oceanic areas require airborne kinematic GPS baselines of many hundreds of kilometers in length. In such instances, with the complications of ionospheric biases, it can be a real...... challenge for traditional differential kinematic GPS software to obtain reasonable solutions. In this paper, we will describe attempts to validate an implementation of the precise point positioning (PPP) technique on an aircraft without the use of a local GPS reference station. We will compare PPP solutions...... of the Arctic Ocean north of Greenland, near-coincident in time and space with the ICESat satellite laser altimeter. Both of these flights were more than 800 km long. Comparisons between different GPS methods and four different software packages do not suggest a clear preference for any one, with the heights...

  20. Methods of sampling airborne fungi in working environments of waste treatment facilities.

    Science.gov (United States)

    Černá, Kristýna; Wittlingerová, Zdeňka; Zimová, Magdaléna; Janovský, Zdeněk

    2016-01-01

    The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. The total number of colony-forming units (CFU)/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p airborne fungi ranged 2×102-1.7×106 CFU/m3 when using the membrane filters (MF) method, and 3×102-6.4×104 CFU/m3 when using the surface air system (SAS) method. Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.